@article{ullmann_kawano_baramsai_bredeweg_couture_haight_jandel_o'donnell_rundberg_vieira_et al._2017, title={Constraining the calculation of U-234,U-236,U-238(n,gamma) cross sections with measurements of the gamma-ray spectra at the DANCE facility}, volume={96}, ISSN={["2469-9993"]}, DOI={10.1103/physrevc.96.024627}, abstractNote={The cross section for neutron capture in the continuum region has been difficult to calculate accurately. Previous results for $^{238}\mathrm{U}$ show that including an $M1$ scissors-mode contribution to the photon strength function resulted in very good agreement between calculation and measurement. This paper extends that analysis to $^{234,236}\mathrm{U}$ by using $\ensuremath{\gamma}$-ray spectra measured with the Detector for Advanced Neutron Capture Experiments (DANCE) at the Los Alamos Neutron Science Center to constrain the photon strength function used to calculate the capture cross section. Calculations using a strong scissors-mode contribution reproduced the measured $\ensuremath{\gamma}$-ray spectra and were in excellent agreement with the reported cross sections for all three isotopes.}, number={2}, journal={PHYSICAL REVIEW C}, author={Ullmann, J. L. and Kawano, T. and Baramsai, B. and Bredeweg, T. A. and Couture, A. and Haight, R. C. and Jandel, M. and O'Donnell, J. M. and Rundberg, R. S. and Vieira, D. J. and et al.}, year={2017}, month={Aug} }
 @article{valenta_baramsai_bredeweg_couture_chyzh_jandel_kroll_krticka_mitchell_o'donnell_et al._2017, title={Examination of photon strength functions for Dy-162,Dy-164 from radiative capture of resonance neutrons}, volume={96}, ISSN={["2469-9993"]}, DOI={10.1103/physrevc.96.054315}, abstractNote={The $\ensuremath{\gamma}$ rays following radiative neutron capture on $^{161,163}\mathrm{Dy}$ targets were measured with the highly segmented $\ensuremath{\gamma}$-ray calorimeter Detector for Advanced Neutron Capture Experiments at the Los Alamos Neutron Science Center. The $\ensuremath{\gamma}$-ray energy spectra for different multiplicities were gathered for tens of $s$-wave resonances of both possible spins in each nucleus. Analysis of these spectra within the statistical model enabled us to draw conclusions about dipole photon strength functions with emphasis on the scissors mode. The photon strength functions best describing Dy data are very similar to previously published results on even-even Gd isotopes. It was shown that the scissors mode plays a significant role in the decay of highly excited states up to the neutron separation energy. Measurement of multiple resonances allowed us to assess the fluctuations of experimental spectra and to compare the fluctuations with simulated ones. The size of measured fluctuations is on average smaller than predicted from simulations. However, the results are puzzling as the difference between simulations within the statistical model and experiment is not consistent for both nuclei.}, number={5}, journal={PHYSICAL REVIEW C}, author={Valenta, S. and Baramsai, B. and Bredeweg, T. A. and Couture, A. and Chyzh, A. and Jandel, M. and Kroll, J. and Krticka, M. and Mitchell, G. E. and O'Donnell, J. M. and et al.}, year={2017}, month={Nov} }
 @article{walker_krticka_baramsai_becvar_bredeweg_chyzh_haight_jandel_kroll_mitchell_et al._2015, title={Measurement of the Mo-97(n,gamma) reaction with the DANCE gamma calorimeter array}, volume={92}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.92.014324}, abstractNote={Spectra of $\ensuremath{\gamma}$ rays following the $^{97}\mathrm{Mo}(n,\ensuremath{\gamma})$ reaction were measured as a function of incident neutron energy with the DANCE (Detector for Advanced Neutron Capture Experiments) array of $160 {\mathrm{BaF}}_{2}$ scintillation detectors at the Los Alamos Neutron Science Center using an enriched $^{97}\mathrm{Mo}$ target. These spectra were used for the assignment of spins of the $^{97}\mathrm{Mo}$ resonances up to neutron energy ${E}_{n}=1.7$ keV, as well as in the study of photon strength functions (PSFs) in $^{98}\mathrm{Mo}$. Analysis of the spectra with the nuclear statistical model showed that they can be well reproduced with the same PSF models which well described the $\ensuremath{\gamma}$ decay following slow neutron capture in $^{95}\mathrm{Mo}$. On the other hand, the spectra are inconsistent with PSFs describing some other experimental data in $^{98}\mathrm{Mo}$.}, number={1}, journal={PHYSICAL REVIEW C}, author={Walker, C. L. and Krticka, M. and Baramsai, B. and Becvar, F. and Bredeweg, T. A. and Chyzh, A. and Haight, R. C. and Jandel, M. and Kroll, J. and Mitchell, G. E. and et al.}, year={2015}, month={Jul} }
 @article{kroll_valenta_krticka_becvar_tomandl_mitchell_2015, title={Photon Strength Functions from Two-Step gamma Cascades Experiment on Gd155-157}, volume={93}, ISSN={["2100-014X"]}, DOI={10.1051/epjconf/20159301036}, abstractNote={Spectra of two-step γ cascades following neutron capture in 155,157 Gd were measured using the two- HPGe-detector facility installed at a pure subthermal neutron beam of the LVR-15 reactor in ˇež near Prague. The main objective of this experiment was to get new information on photon strength functions with the emphasis put on the role of M 1 scissors mode vibration. An analysis of accumulated γ -ray spectra, made within the statistical model, leads to the conclusion that the scissors mode significantly affects γ decay of all states of studied nuclei. The obtained results for energy, damping width and summed B (M 1) ↑ strength of the scissors mode are compared with what has been deduced from neutron capture experiments performed at DANCE detector installed in Los Alamos National Laboratory, NRF data for the ground state scissors mode and from the data on 3 He-induced reactions using the so-called Oslo method.}, journal={CGS15 - CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS}, author={Kroll, J. and Valenta, S. and Krticka, M. and Becvar, F. and Tomandl, I. and Mitchell, G. E.}, year={2015} }
 @article{baramsai_becvar_bredeweg_haight_jandel_kroll_krticka_mitchell_o'donnell_rundberg_et al._2015, title={Scissors Mode of Dy-162 Studied from Resonance Neutron Capture}, volume={93}, ISSN={["2100-014X"]}, DOI={10.1051/epjconf/20159301037}, abstractNote={Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3He-induced reactions, (n,γ) experiments on Gd isotopes, and (γ,γ’) reactions.}, journal={CGS15 - CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS}, author={Baramsai, B. and Becvar, F. and Bredeweg, T. A. and Haight, R. C. and Jandel, M. and Kroll, J. and Krticka, M. and Mitchell, G. E. and O'Donnell, J. M. and Rundberg, R. S. and et al.}, year={2015} }
 @article{ullmann_kawano_bredeweg_couture_haight_jandel_o'donnell_rundberg_vieira_wilhelmy_et al._2014, title={Cross section and.gamma-ray spectra for U-238(n,gamma) measured with the DANCE detector array at the Los Alamos Neutron Science Center}, volume={89}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.89.034603}, abstractNote={Background: Accurate knowledge of the $^{238}\mathrm{U}$($n$,$\ensuremath{\gamma}$) cross section is important for developing theoretical nuclear reaction models and for applications. However, capture cross sections are difficult to calculate accurately and often must be measured.Purpose: We seek to confirm previous measurements and test cross-section calculations with an emphasis on the unresolved resonance region from 1 to 500 keV.Method: Cross sections were measured from 10 eV to 500 keV using the DANCE detector array at the LANSCE spallation neutron source. The measurements used a thin target, 48 mg/cm${}^{2}$ of depleted uranium. Gamma cascade spectra were also measured to provide an additional constraint on calculations. The data are compared to cross-section calculations using the code CoH${}_{3}$ and cascade spectra calculations made using the code dicebox.Results: This new cross-section measurement confirms the previous data. The measured gamma-ray spectra suggest the need for additional low-lying dipole strength in the radiative strength function. New Hauser-Feshbach calculations including this strength accurately predict the capture cross section without renormalization.Conclusions: The present cross-section data confirm previous measurements. Including additional low-lying dipole strength in the radiative strength function may lead to more accurate cross-section calculations in nuclei where $\ensuremath{\langle}{\ensuremath{\Gamma}}_{\ensuremath{\gamma}}\ensuremath{\rangle}$ has not been measured.}, number={3}, journal={PHYSICAL REVIEW C}, author={Ullmann, J. L. and Kawano, T. and Bredeweg, T. A. and Couture, A. and Haight, R. C. and Jandel, M. and O'Donnell, J. M. and Rundberg, R. S. and Vieira, D. J. and Wilhelmy, J. B. and et al.}, year={2014}, month={Mar} }
 @article{ullmann_mosby_bredeweg_couture_haight_jandel_kawano_o'donnell_rundberg_vieira_et al._2014, title={Neutron Capture Cross Sections and Gamma Emission Spectra from Neutron Capture on U-234,U-236,U-238 Measured with DANCE}, volume={119}, ISSN={["1095-9904"]}, DOI={10.1016/j.nds.2014.08.008}, journal={NUCLEAR DATA SHEETS}, author={Ullmann, J. L. and Mosby, S. and Bredeweg, T. A. and Couture, A. J. and Haight, R. C. and Jandel, M. and Kawano, T. and O'Donnell, J. M. and Rundberg, R. S. and Vieira, D. J. and et al.}, year={2014}, month={May}, pages={22–25} }
 @article{gunsing_fraval_mathelie_valenta_becvar_rusev_tonchev_mitchell_baramsai_altstadt_et al._2014, title={Spin measurements of n+Sr-87 for level density studies}, volume={119}, journal={Nuclear Data Sheets}, author={Gunsing, F. and Fraval, K. and Mathelie, M. and Valenta, S. and Becvar, F. and Rusev, G. and Tonchev, A. P. and Mitchell, G. and Baramsai, B. and Altstadt, S. and et al.}, year={2014}, pages={E132–136} }
 @article{kroll_agvaanluvsan_baramsai_becker_becvar_bredeweg_chyzh_couture_dashdorj_haight_et al._2014, title={Systematics of Scissors Mode in Gd Nuclei from Experiments with the DANCE Detector}, volume={119}, ISSN={["1095-9904"]}, DOI={10.1016/j.nds.2014.08.044}, abstractNote={Multi-step cascade γ-ray spectra from neutron capture at isolated resonances of 152,154−158Gd nuclei were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The main objective of these experiments was to obtain new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. An analysis of the data obtained shows that the scissors mode plays a significant role in the ground state transitions, as well as in the transitions populating all excited states of the studied nuclei. The estimates of the scissors mode strength indicate that for 157,159Gd this strength is significantly higher than in neighboring even–even nuclei 156,158Gd. The results are compared with the (γ,γ′) data for the ground-state scissors mode and the results from 3He-induced reactions.}, journal={NUCLEAR DATA SHEETS}, author={Kroll, J. and Agvaanluvsan, U. and Baramsai, B. and Becker, J. A. and Becvar, F. and Bredeweg, T. A. and Chyzh, A. and Couture, A. and Dashdorj, D. and Haight, R. C. and et al.}, year={2014}, month={May}, pages={158–161} }
 @article{baramsai_mitchell_walker_bredeweg_couture_haight_jandel_mosb_o'donnell_rundberg_et al._2013, title={(n,gamma) Experiments On Tin Isotopes}, volume={1525}, ISSN={["0094-243X"]}, DOI={10.1063/1.4802394}, abstractNote={Neutron capture experiments on highly enriched 117,119Sn isotopes were performed with the DANCE detector array located at the Los Alamos Neutron Science Center. The DANCE detector provides detailed information about the multi-step γ-ray cascade following neutron capture. Analysis of the experimental data provides important information to improve understanding of the neutron capture reaction, including a test of the statistical model, the assignment of spins and parities of neutron resonances, and information concerning the Photon Strength Function (PSF) and Level Density (LD) below the neutron separation energy. Preliminary results for the (n,γ) reaction on 117,119Sn are presented. Resonance spins of the odd-A tin isotopes were almost completely unknown. Resonance spins and parities have been assigned via analysis of the multi-step γ-ray spectra and directional correlations.}, journal={APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY}, author={Baramsai, B. and Mitchell, G. E. and Walker, C. L. and Bredeweg, T. A. and Couture, A. and Haight, R. C. and Jandel, M. and Mosb, S. and O'Donnell, J. M. and Rundberg, R. S. and et al.}, year={2013}, pages={577–580} }
 @article{pogrebnyak_howard_iliadis_longland_mitchell_2013, title={Mean proton and alpha-particle reduced widths of the Porter-Thomas distribution and astrophysical applications}, volume={88}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.88.015808}, abstractNote={The Porter-Thomas distribution is a key prediction of the Gaussian orthogonal ensemble in random matrix theory. It is routinely used to provide a measure for the number of levels that are missing in a given resonance analysis. The Porter-Thomas distribution is also of crucial importance for estimates of thermonuclear reaction 
rates where the contributions of certain unobserved resonances to the total reaction rate need to be taken into account. In order to estimate such contributions by randomly sampling over the Porter-Thomas distribution, 
the mean value of the reduced width must be known. We present mean reduced width values for protons and α particles of compound nuclei in the A = 28–67 mass range. The values are extracted from charged-particle 
elastic scattering and reaction data that weremeasured at the riangle Universities Nuclear Laboratory over several decades. Our new values differ significantly from those previously reported that were based on a preliminary analysis of a smaller data set. As an example for the application of our results, we present new thermonuclear rates for the 40Ca(α,γ)44Ti reaction, which is important for 44Ti production in core-collapse supernovae, and compare with previously reported results.}, number={1}, journal={PHYSICAL REVIEW C}, publisher={American Physical Society (APS)}, author={Pogrebnyak, I. and Howard, C. and Iliadis, C. and Longland, R. and Mitchell, G. E.}, year={2013}, month={Jul} }
 @article{baramsai_kroll_mitchell_agvaanluvsan_becvar_bredeweg_chyzh_couture_dashdorj_haight_et al._2013, title={Photon strength functions of Gd-156 from radiative capture of resonance neutrons}, volume={87}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.87.044609}, abstractNote={The ${}^{155}$Gd($n,\ensuremath{\gamma}$) reaction was measured with the DANCE $\ensuremath{\gamma}$-ray calorimeter (consisting of 160 BaF${}_{2}$ scintillation detectors) at the Los Alamos Neutron Science Center. The $\ensuremath{\gamma}$-ray energy spectra for different multiplicities were obtained for the $s$-wave resonances. The shapes of these spectra were compared with simulations based on the use of the dicebox statistical model code. Simulations showed that the photon strength functions (PSFs) successfully describing the decay of ${}^{156}$Gd are very similar to the PSFs describing the decay of previously published ${}^{158}$Gd results. It was demonstrated that the scissors mode is required not only for the ground-state transitions, but also for transitions between excited states.}, number={4}, journal={PHYSICAL REVIEW C}, author={Baramsai, B. and Kroll, J. and Mitchell, G. E. and Agvaanluvsan, U. and Becvar, F. and Bredeweg, T. A. and Chyzh, A. and Couture, A. and Dashdorj, D. and Haight, R. C. and et al.}, year={2013}, month={Apr} }
 @article{kroll_becvar_krticka_valenta_baramsai_mitchell_walker_bredeweg_couture_haight_et al._2013, title={Scissors mode of Gd nuclei measured, with the DANCE detector}, volume={T154}, ISSN={["1402-4896"]}, DOI={10.1088/0031-8949/2013/t154/014009}, abstractNote={Spectra of γ-rays following the neutron capture at isolated resonances of stable Gd nuclei were measured with the DANCE detector. The objectives were to obtain new information on the photon strength of 153,155−159Gd with emphasis on the role of the M1 scissors-mode vibration. An analysis of the data obtained clearly indicates that the scissors mode is built not only on the ground state, but also on all excited levels of the nuclei studied. Our approach allows estimating the summed scissors-mode strength even for odd product nuclei for which conventional nuclear resonance fluorescence measurements yield only limited information. Our data indicate that for 157,159Gd the strength is significantly higher compared to 156,158Gd.}, journal={PHYSICA SCRIPTA}, author={Kroll, J. and Becvar, F. and Krticka, M. and Valenta, S. and Baramsai, B. and Mitchell, G. E. and Walker, C. L. and Bredeweg, T. A. and Couture, A. and Haight, R. C. and et al.}, year={2013}, month={May} }
 @article{kroll_baramsai_mitchell_agvaanluvsan_becvar_bredeweg_chyzh_couture_dashdorj_haight_et al._2013, title={Strength of the scissors mode in odd-mass Gd isotopes from the radiative capture of resonance neutrons}, volume={88}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.88.034317}, abstractNote={Radiative neutron capture reaction was measured in the resolved resonance region for ${}^{152,154,156,158}$Gd targets with the Detector for Advanced Neutron Capture Experiments $\ensuremath{\gamma}$-ray calorimeter at the Los Alamos Neutron Science Center. The $\ensuremath{\gamma}$-ray energy spectra for different multiplicities were obtained for several $s$-wave resonances in each nucleus. These spectra were analyzed within the extreme statistical model to provide unique information on the photon strength functions and especially on the scissors mode in odd Gd isotopes. The main result of this analysis is that in all nuclei scissors-mode resonances are built on excited levels and not only on their ground states. The strength of the mode found in ${}^{153}$Gd and ${}^{155}$Gd is comparable to the strength observed in well-deformed even-even Gd isotopes while it is substantially higher in ${}^{157,159}$Gd. The difference in observed strengths of the scissors mode indicates an existence of an even-odd effect in this quantity.}, number={3}, journal={PHYSICAL REVIEW C}, author={Kroll, J. and Baramsai, B. and Mitchell, G. E. and Agvaanluvsan, U. and Becvar, F. and Bredeweg, T. A. and Chyzh, A. and Couture, A. and Dashdorj, D. and Haight, R. C. and et al.}, year={2013}, month={Sep} }
 @article{stephenson_crawford_furman_lychagin_muzichka_nekhaev_sharapov_shvetsov_strelkov_levakov_et al._2012, title={Experiment on direct nn scattering - The radiation-induced outgassing complication}, volume={895}, ISSN={["0375-9474"]}, DOI={10.1016/j.nuclphysa.2012.09.005}, abstractNote={The first direct neutron–neutron scattering experiment using the YAGUAR pulsed reactor has yielded initial results. They show a unforeseen significant thermal neutron background as a result of radiation-induced desorption within the scattering chamber. Thermal neutrons are mostly scattering not from other neutrons but instead from the desorbed gas molecules. Analysis of the obtained neutron time-of-flight spectra suggests neutron scattering from H2 molecules. The presented desorption model agrees with our experimental value of the desorption yield ηγ=0.02molecules/gamma. Possible techniques to reduce the effect of the desorption background are presented.}, journal={NUCLEAR PHYSICS A}, author={Stephenson, S. L. and Crawford, B. E. and Furman, W. I. and Lychagin, E. V. and Muzichka, A. Yu. and Nekhaev, G. V. and Sharapov, E. I. and Shvetsov, V. N. and Strelkov, A. V. and Levakov, B. G. and et al.}, year={2012}, month={Dec}, pages={33–43} }
 @article{baramsai_mitchell_walker_bredeweg_couture_haight_jandel_o'donnell_rundberg_ullmann_et al._2012, title={Neutron capture experiments with 4 pi DANCE Calorimeter}, volume={21}, ISSN={["2100-014X"]}, DOI={10.1051/epjconf/20122103002}, abstractNote={In recent years we have performed a series of neutron capture experiments with the DANCE detector array located at the Los Alamos Neutron Science Center. The radiative decay spectrum from the compound nucleus contains important information about nuclear structure and the reaction mechanism. The primary goals of the measure- ments are to obtain improved capture cross sections, to determine properties of the photon strength function, to improve neutron level densities and strength functions by determin- ing the spin and parity of the capturing states. We shall present examples of our recent results.}, journal={CNR*11 - THIRD INTERNATIONAL WORKSHOP ON COMPOUND NUCLEAR REACTIONS AND RELATED TOPICS}, author={Baramsai, B. and Mitchell, G. E. and Walker, C. L. and Bredeweg, T. A. and Couture, A. and Haight, R. C. and Jandel, M. and O'Donnell, J. M. and Rundberg, R. S. and Ullmann, J. and et al.}, year={2012} }
 @article{baramsai_mitchell_agvaanluvsan_becvar_bredeweg_chyzh_couture_dashdorj_haight_jandel_et al._2012, title={Neutron resonance parameters in Gd-155 measured with the DANCE gamma-ray calorimeter array}, volume={85}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.85.024622}, abstractNote={The ${}^{155}$Gd($n$,$\ensuremath{\gamma}$) reaction was measured with the DANCE $\ensuremath{\gamma}$-ray calorimeter at the Los Alamos Neutron Science Center. Spins were determined for the $s$-wave resonances by analysis of the $\ensuremath{\gamma}$-ray multiplicity distributions. The analysis was performed with a pattern recognition method. The resulting level densities for the $J=1$ and 2 resonances are in qualitative agreement with the expected 2$J$ $+$ 1 dependence. The average $s$-wave resonance spacing was determined to be ${D}_{0}=1.62$ $\ifmmode\pm\else\textpm\fi{}$ 0.15 eV. Analysis of the neutron resonances with the code sammy yielded the $s$-wave strength function ${S}_{0}=1.99\ifmmode\pm\else\textpm\fi{}0.28\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and the average total radiative width ${\ensuremath{\Gamma}}_{\ensuremath{\gamma}}$ $=$ 120 $\ifmmode\pm\else\textpm\fi{}$ 3 meV.}, number={2}, journal={PHYSICAL REVIEW C}, author={Baramsai, B. and Mitchell, G. E. and Agvaanluvsan, U. and Becvar, F. and Bredeweg, T. A. and Chyzh, A. and Couture, A. and Dashdorj, D. and Haight, R. C. and Jandel, M. and et al.}, year={2012}, month={Feb} }
 @article{chyzh_baramsai_becker_becvar_bredeweg_couture_dashdorj_haight_jandel_kroll_et al._2011, title={Measurement of the Gd-157(n,gamma) reaction with the DANCE gamma calorimeter array}, volume={84}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.84.014306}, abstractNote={The {sup 157}Gd(n,{gamma}) reaction was measured with the DANCE {gamma} calorimeter (consisting of 160 BaF{sub 2} scintillation detectors) at the Los Alamos Neutron Science Center. The multiplicity distributions of the {gamma} decay were used to determine the resonance spins up to E{sub n}=300 eV. The {gamma}-ray energy spectra for different multiplicities were measured for the s-wave resonances. The shapes of these spectra were compared with simulations based on the use of the DICEBOX statistical model code. Simulations showed that the scissors mode is required not only for the ground-state transitions but also for transitions between excited states.}, number={1}, journal={PHYSICAL REVIEW C}, author={Chyzh, A. and Baramsai, B. and Becker, J. A. and Becvar, F. and Bredeweg, T. A. and Couture, A. and Dashdorj, D. and Haight, R. C. and Jandel, M. and Kroll, J. and et al.}, year={2011}, month={Jul} }
 @article{ullmann_couture_keksis_vieira_o'donnell_wouters_jandel_haight_rundberg_bredeweg_et al._2011, title={Measurement of the U-238 Neutron-capture Cross Section and Gamma-emission Spectra from 10 eV to 100 keV Using the DANCE Detector at LANSCE}, volume={59}, ISSN={["1976-8524"]}, DOI={10.3938/jkps.59.1406}, abstractNote={A careful new measurement of the {sup 238}U(n,{gamma}) cross section from 10 eV to 100 keV has been made using the DANCE detector at LANSCE. DANCE is a 4{pi} calorimetric scintillator array consisting of 160 BaF{sub 2} crystals. Measurements were made on a 48 mg/cm{sup 2} depleted uranium target. The cross sections are in general good agreement with previous measurements. The gamma-ray emission spectra, as a function of gamma multiplicity, were also measured and compared to model calculations.}, number={2}, journal={JOURNAL OF THE KOREAN PHYSICAL SOCIETY}, author={Ullmann, J. L. and Couture, A. J. and Keksis, A. L. and Vieira, D. J. and O'Donnell, J. M. and Wouters, J. M. and Jandel, M. and Haight, R. C. and Rundberg, R. S. and Bredeweg, T. A. and et al.}, year={2011}, month={Aug}, pages={1406–1409} }
 @article{becvar_koehler_krticka_mitchell_ullmann_2011, title={Optimized gamma-multiplicity-based spin assignments of s-wave neutron resonances}, volume={647}, ISSN={["0168-9002"]}, DOI={10.1016/j.nima.2011.04.026}, abstractNote={The multiplicity of γ‐ray emission following neutron capture at isolated resonances carries valuable information on the resonance spin. Several methods utilizing this information have been developed. The latest method was recently introduced for analyzing the data from time-of-flight measurements with 4π γ‐calorimetric detection systems. The present paper describes a generalization of this method. The goal is the separation of the γ‐emission yields belonging to the two neutron capturing state spins of isolated (or even unresolved) s-wave neutron resonances on targets with non-zero spin. The formalism for performing this separation is described and then tested on artificially generated data. This new method was applied to the γ‐multiplicity data obtained for the Sm147(n,γ)Sm148 reaction using the DANCE detector system at the LANSCE facility at Los Alamos National Laboratory. The analyzing power of the upgraded method is supported by combined dicebox and geant4 simulations of the fluctuation properties of the γ‐multiplicity distributions.}, number={1}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Becvar, F. and Koehler, P. E. and Krticka, M. and Mitchell, G. E. and Ullmann, J. L.}, year={2011}, month={Aug}, pages={73–85} }
 @article{dashdorj_mitchell_kawano_devlin_fotiades_nelson_becker_wu_garrett_kuneida_2010, title={(n,2n) and (n,3n) cross-sections of neutron-induced reactions on Sm-150 for E-n=1-35 MeV}, volume={268}, ISSN={["1872-9584"]}, DOI={10.1016/j.nimb.2009.10.189}, abstractNote={Cross-section measurements were made of prompt discrete γ-ray production as a function of incident neutron energy (En=1–135MeV) on a 150Sm sample of 1550mg/cm2 of Sm2O3 enriched to 95.6% in 150Sm. Results are compared with enhanced Hauser–Feshbach model calculations including the pre-equilibrium reactions. Energetic neutrons were delivered by the Los Alamos Neutron Science Center facility. The prompt-reaction γ-rays were detected with the compton-suppressed germanium array for neutron-induced excitations (GEANIE). Incident neutron energies were determined by the time-of-flight technique. Excitation functions for thirteen individual γ-rays up to Ex=0.8MeV in 149Sm and one γ-ray transition between the first excited and ground state in 148Sm were measured. Partial γ-ray cross-sections were calculated using GNASH, an enhanced Hauser–Feshbach statistical nuclear reaction model code, and compared with the experimental results. The particle transmission coefficients were calculated with new systematic “global” optical model potential parameters. A coupled-channels optical model based on a soft rotor model was employed to calculate the particle transmission coefficients. The pre-equilibrium part of the spin-distribution in 150Sm was calculated using the quantum mechanical theory of Feshbach, Kerman, and Koonin (FKK) and incorporated into the GNASH reaction model code. The partial cross-sections for discrete γ-ray cascade paths leading to the ground state in 149Sm and 148Sm have been summed (without double counting) to estimate lower limits for reaction cross-sections. These lower limits are combined with Hauser–Feshbach model calculations to deduce the reaction channel cross-sections. These reaction channel cross-sections agree with previously measured experimental and ENDF/B-VII evaluations.}, number={2}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Dashdorj, D. and Mitchell, G. E. and Kawano, T. and Devlin, M. and Fotiades, N. and Nelson, R. O. and Becker, J. A. and Wu, C. Y. and Garrett, P. E. and Kuneida, S.}, year={2010}, month={Jan}, pages={114–119} }
 @article{toft_larsen_agvaanluvsan_buerger_guttormsen_mitchell_nyhus_schiller_siem_syed_et al._2010, title={Level densities and gamma-ray strength functions in Sn isotopes}, volume={81}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.81.064311}, abstractNote={The nuclear level densities of $^{118,119}\mathrm{Sn}$ and the $\ensuremath{\gamma}$-ray strength functions of $^{116,118,119}\mathrm{Sn}$ below the neutron separation energy are extracted with the Oslo method using the ($^{3}\mathrm{He}$,$\ensuremath{\alpha}\ensuremath{\gamma}$) and ($^{3}\mathrm{He}$,$^{3}\mathrm{He}$${}^{\ensuremath{'}}\ensuremath{\gamma}$) reactions. The level-density function of $^{119}\mathrm{Sn}$ displays steplike structures. The microcanonical entropies are deduced from the level densities, and the single neutron entropy of $^{119}\mathrm{Sn}$ is determined to be $1.7$ $\ifmmode\pm\else\textpm\fi{}$ $0.2$ ${k}_{B}$. Results from a combinatorial model support the interpretation that some of the low-energy steps in the level density function are caused by neutron pair breaking. An enhancement in all the $\ensuremath{\gamma}$-ray strength functions of $^{116\ensuremath{-}119}\mathrm{Sn}$, compared to standard models for radiative strength, is observed for the $\ensuremath{\gamma}$-ray energy region of $\ensuremath{\simeq}$$4\ensuremath{-}11$ MeV. These small resonances all have a centroid energy of $8.0(1)$ MeV and an integrated strength corresponding to $1.7(9)%$ of the classical Thomas-Reiche-Kuhn sum rule. The Sn resonances may be due to electric dipole neutron skin oscillations or to an enhancement of the giant magnetic dipole resonance.}, number={6}, journal={PHYSICAL REVIEW C}, author={Toft, H. K. and Larsen, A. C. and Agvaanluvsan, U. and Buerger, A. and Guttormsen, M. and Mitchell, G. E. and Nyhus, H. T. and Schiller, A. and Siem, S. and Syed, N. U. H. and et al.}, year={2010}, month={Jun} }
 @article{mitchell_richter_weidenmueller_2010, title={Random matrices and chaos in nuclear physics: Nuclear reactions}, volume={82}, ISSN={["1539-0756"]}, DOI={10.1103/revmodphys.82.2845}, abstractNote={The application of random-matrix theory (RMT) to compound-nucleus (CN) reactions is reviewed. An introduction into the basic concepts of nuclear scattering theory is followed by a survey of phenomenological approaches to CN scattering. The implementation of a random-matrix approach into scattering theory leads to a statistical theory of CN reactions. Since RMT applies generically to chaotic quantum systems, that theory is, at the same time, a generic theory of quantum chaotic scattering. It uses a minimum of input parameters (average S matrix and mean level spacing of the CN). Predictions of the theory are derived with the help of field-theoretical methods adapted from condensed-matter physics and compared with those of phenomenological approaches. Thorough tests of the theory are reviewed, as are applications in nuclear physics, with special attention given to violation of symmetries (isospin and parity) and time-reversal invariance.}, number={4}, journal={REVIEWS OF MODERN PHYSICS}, author={Mitchell, G. E. and Richter, A. and Weidenmueller, H. A.}, year={2010}, month={Oct} }
 @article{agvaanluvsan_larsen_chankova_guttormsen_mitchell_schiller_siem_voinov_2009, title={Enhanced Radiative Strength in the Quasicontinuum of Sn-117}, volume={102}, ISSN={["1079-7114"]}, DOI={10.1103/physrevlett.102.162504}, abstractNote={The radiative strength function of 117Sn has been measured up to the neutron separation energy using the (3He, 3He' gamma) reaction. An increase in the slope of the strength function around E gamma=4.5 MeV indicates the onset of a resonancelike structure, giving a significant enhancement of the radiative strength function compared to standard models in the energy region 4.5<or=E gamma<or=8.0 MeV. For the first time, the functional form of this resonancelike structure has been measured in an odd tin nucleus below neutron threshold in the quasicontinuum region.}, number={16}, journal={PHYSICAL REVIEW LETTERS}, author={Agvaanluvsan, U. and Larsen, A. C. and Chankova, R. and Guttormsen, M. and Mitchell, G. E. and Schiller, A. and Siem, S. and Voinov, A.}, year={2009}, month={Apr} }
 @article{agvaanluvsan_larsen_guttormsen_chankova_mitchell_schiller_siem_voinov_2009, title={Evidence for the pair-breaking process in Sn-116,Sn-117}, volume={79}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.79.014320}, abstractNote={The nuclear level densities of {sup 116,117}Sn below the neutron separation energy have been determined experimentally from the ({sup 3}He,{alpha}{gamma}) and ({sup 3}He,{sup 3}He{sup '}{gamma}) reactions, respectively. The level densities show a characteristic exponential increase and a difference in magnitude due to the odd-even effect of the nuclear systems. In addition, the level densities display pronounced step-like structures that are interpreted as signatures of subsequent breaking of nucleon pairs.}, number={1}, journal={PHYSICAL REVIEW C}, author={Agvaanluvsan, U. and Larsen, A. C. and Guttormsen, M. and Chankova, R. and Mitchell, G. E. and Schiller, A. and Siem, S. and Voinov, A.}, year={2009}, month={Jan} }
 @misc{weidenmueller_mitchell_2009, title={Random matrices and chaos in nuclear physics: Nuclear structure}, volume={81}, ISSN={["1539-0756"]}, DOI={10.1103/revmodphys.81.539}, abstractNote={The authors review the evidence for the applicability of random--matrix theory to nuclear spectra. In analogy to systems with few degrees of freedom, one speaks of chaos (more accurately: quantum chaos) in nuclei whenever random--matrix predictions are fulfilled. An introduction into the basic concepts of random--matrix theory is followed by a survey over the extant experimental information on spectral fluctuations, including a discussion of the violation of a symmetry or invariance property. Chaos in nuclear models is discussed for the spherical shell model, for the deformed shell model, and for the interacting boson model. Evidence for chaos also comes from random--matrix ensembles patterned after the shell model such as the embedded two--body ensemble, the two--body random ensemble, and the constrained ensembles. All this evidence points to the fact that chaos is a generic property of nuclear spectra, except for the ground--state regions of strongly deformed nuclei.}, number={2}, journal={REVIEWS OF MODERN PHYSICS}, author={Weidenmueller, H. A. and Mitchell, G. E.}, year={2009}, pages={539–589} }
 @article{sheets_agvaanluvsan_becker_becvar_bredeweg_haight_jandel_krticka_mitchell_o'donnell_et al._2009, title={Test of the statistical model in Mo-96 with the BaF2 gamma calorimeter DANCE array}, volume={79}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.79.024301}, abstractNote={The {gamma}-ray cascades following the {sup 95}Mo(n,{gamma}){sup 96}Mo reaction were studied with the {gamma} calorimeter DANCE (Detector for Advanced Neutron Capture Experiments) consisting of 160 BaF{sub 2} scintillation detectors at the Los Alamos Neutron Science Center. The {gamma}-ray energy spectra for different multiplicities were measured for s- and p-wave resonances below 2 keV. The shapes of these spectra were found to be in very good agreement with simulations using the DICEBOX statistical model code. The relevant model parameters used for the level density and photon strength functions were identical with those that provided the best fit of the data from a recent measurement of the thermal {sup 95}Mo(n,{gamma}){sup 96}Mo reaction with the two-step-cascade method. The reported results strongly suggest that the extreme statistical model works very well in the mass region near A=100.}, number={2}, journal={PHYSICAL REVIEW C}, author={Sheets, S. A. and Agvaanluvsan, U. and Becker, J. A. and Becvar, F. and Bredeweg, T. A. and Haight, R. C. and Jandel, M. and Krticka, M. and Mitchell, G. E. and O'Donnell, J. M. and et al.}, year={2009}, month={Feb} }
 @article{algin_agvaanluvsan_guttormsen_larsen_mitchell_rekstad_schiller_siem_voinov_2008, title={Thermodynamic properties of Fe-56,Fe-57}, volume={78}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.78.054321}, abstractNote={Nuclear level densities for {sup 56,57}Fe have been extracted from the primary {gamma}-ray spectra using ({sup 3}He, {sup 3}He{sup '}{gamma}) and ({sup 3}He, {alpha}{gamma}) reactions. Nuclear thermodynamic properties for {sup 56}Fe and {sup 57}Fe are investigated using the experimental level densities. These properties include entropy, Helmholtz free energy, caloric curves, chemical potential, and heat capacity. In particular, the breaking of Cooper pairs and single-quasiparticle entropy are discussed and shown to be important concepts for describing nuclear level density. Microscopic model calculations are performed for level densities of {sup 56,57}Fe. The experimental and calculated level densities are compared. The average number of broken Cooper pairs and the parity distribution are extracted as a function of excitation energy for {sup 56,57}Fe from the model calculations.}, number={5}, journal={PHYSICAL REVIEW C}, author={Algin, E. and Agvaanluvsan, U. and Guttormsen, M. and Larsen, A. C. and Mitchell, G. E. and Rekstad, J. and Schiller, A. and Siem, S. and Voinov, A.}, year={2008}, month={Nov} }
 @article{krticka_becvar_tomandl_rusev_agvaanluvsan_mitchell_2008, title={Two-step gamma cascades following thermal neutron capture in Mo-95}, volume={77}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.77.054319}, abstractNote={A strong enhancement of the photon strength function at low {gamma}-ray energies was recently reported for several Mo isotopes. To study this enhancement further we have measured the spectra of two-step {gamma} cascades following thermal neutron capture in {sup 95}Mo. These spectra were compared with simulations of the {gamma} decay of {sup 96}Mo performed with the aid of the dicebox algorithm. Simulations with a large number of model combinations of photon strength functions for E1,M1, and E2 radiation are not consistent with the strong enhancement observed in the {sup 96}Mo({sup 3}He,{sup 3}He{sup '}{gamma}){sup 96}Mo and {sup 97}Mo({sup 3}He,{alpha}{gamma}){sup 96}Mo reactions. Predictions based on a combination of E1,M1, and E2 photon strength functions with no enhancement of the photon strength functions at low {gamma}-ray energies are in good agreement with the two-step {gamma} cascade data.}, number={5}, journal={PHYSICAL REVIEW C}, author={Krticka, M. and Becvar, F. and Tomandl, I. and Rusev, G. and Agvaanluvsan, U. and Mitchell, G. E.}, year={2008}, month={May} }
 @article{shriner_pato_mitchell_tufaile_2007, title={A thermodynamic analysis of energy eigenvalues}, volume={581}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2007.08.171}, abstractNote={The use of the thermodynamic “internal energy” U as a tool for characterizing eigenvalue spectra is examined via Monte Carlo studies. We show that for pure and complete spectra, internal energy provides significant separation between individual Gaussian orthogonal ensemble (GOE) and Poisson spectra for spectra with as few as 30–40 levels. We also demonstrate that internal energy is sensitive to the presence of missing or spurious levels in GOE spectra. Comparison of the behavior of U and Δ3 for imperfect spectra shows that the relative variance of U is smaller; therefore, U is less sensitive to experimental limitations affecting the quality of data than is Δ3.}, number={3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Shriner, J. F., Jr. and Pato, M. P. and Mitchell, G. E. and Tufaile, A. P. B.}, year={2007}, month={Nov}, pages={831–838} }
 @article{muzichka_furman_lychagin_krylov_nekhaev_sharapov_shvetsov_strelkov_levakov_lyzhin_et al._2007, title={Background determination for the neutron-neutron scattering experiment at the reactor YAGUAR}, volume={789}, ISSN={["1873-1554"]}, DOI={10.1016/j.nuclphysa.2007.03.163}, abstractNote={Abstract The motivation and design is outlined for the experiment to measure the neutron–neutron singlet scattering length directly with thermal neutrons at the pulsed reactor YAGUAR. A statistical accuracy of 3% can be reached, though achieving the goal of an overall accuracy of 3–5% for the nn-scattering length depends on the background level. Possible sources of background are discussed in depth and the results of extensive modeling of the background are presented. Measurements performed at YAGUAR to test these background calculations are described. The experimental results indicate an anticipated background level up to 30% relative to the expected nn effect at the maximal energy burst of the reactor. The conclusion is made that the nn experiment at YAGUAR is feasible to produce the first directly measured value for the neutron–neutron scattering length.}, journal={NUCLEAR PHYSICS A}, author={Muzichka, A. Yu. and Furman, W. I. and Lychagin, E. V. and Krylov, A. R. and Nekhaev, G. V. and Sharapov, E. I. and Shvetsov, V. N. and Strelkov, A. V. and Levakov, B. G. and Lyzhin, A. E. and et al.}, year={2007}, month={Jun}, pages={30–45} }
 @article{algin_schiller_voinov_agvaanluvsan_belgya_bernstein_brune_chankova_garrett_grimes_et al._2007, title={Bulk properties of iron isotopes}, volume={70}, ISSN={["1562-692X"]}, DOI={10.1134/S1063778807090232}, abstractNote={Nuclear level densities and radiative strength functions (RSFs) in 56Fe and 57Fe were measured using the 57Fe(3He, αγ) and 57Fe(3He, 3He′γ) reactions, respectively, at the Oslo Cyclotron Laboratory. A low-energy enhancement in the RSF below 4-MeV energy was observed. This finding cannot be explained by common theoretical models. In a second experiment, two-step cascade intensities with soft primary transitions from the 56Fe(n, 2γ) reaction were measured. The agreement between the two experiments confirms the low-energy enhancement in the RSFs. In a third experiment, the neutron evaporation spectrum from the 55Mn(d, n)56Fe reaction was measured at 7-MeV deuteron energy at the John Edwards Accelerator Laboratory at Ohio University. Comparison of the level density of 56Fe obtained from the first and third experiments gives an overall good agreement. Furthermore, observed enhancement for soft γ rays is strengthened by the last experiment.}, number={9}, journal={PHYSICS OF ATOMIC NUCLEI}, author={Algin, E. and Schiller, A. and Voinov, A. and Agvaanluvsan, U. and Belgya, T. and Bernstein, L. A. and Brune, C. R. and Chankova, R. and Garrett, P. E. and Grimes, S. M. and et al.}, year={2007}, month={Sep}, pages={1634–1639} }
 @article{dashdorj_kawano_garrett_becker_agvaanluvsan_bernstein_chadwick_devlin_fotiades_mitchell_et al._2007, title={Effect of preequilibrium spin distribution on Ti-48+n cross sections}, volume={75}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.75.054612}, abstractNote={Nuclear model calculations of discrete {gamma}-ray production cross sections produced in {sup 48}Ti(n,n{sup '}{gamma}{sub i}){sup 48}Ti and {sup 48}Ti(n,2n{gamma}{sub i}){sup 47}Ti reactions were made as a function of incident neutron energy from E{sub n}=1 MeV to 35 MeV and compared with new experimental results using the large-scale Compton-suppressed germanium array for neutron induced excitations (GEANIE) at LANSCE. The Hauser-Feshbach reaction code GNASH, incorporating the spin distribution for the preequilibrium process calculated with the Feshbach-Kerman-Koonin (FKK) quantum-mechanical preequilibrium theory, was used to calculate partial {gamma}-ray transition cross sections. The comparisons of calculated and experimental data demonstrate that, the FKK model for preequilibrium leads a better overall reproduction of the experimental data above E{sub n}=10 MeV, where preequilibrium processes are important. The FKK calculation predicts a strong reduction in the high-spin state population in {sup 48}Ti by inelastic scattering. Population of low-spin states was also affected, however the change in the low-lying 983.5-keV (2{sup +}) state production is small because almost all {gamma}-ray decay cascades feed this transition. In addition, the FKK calculation has a significant impact on the partial {gamma}-ray transition cross sections for the (n,2n) reaction above E{sub n}=15 MeV. The calculated cross sections for high-spin states in {sup 47}Timore » are reduced, and those from the low-spin states are enhanced, in agreement with the experimental cross section data.« less}, number={5}, journal={PHYSICAL REVIEW C}, author={Dashdorj, D. and Kawano, T. and Garrett, P. E. and Becker, J. A. and Agvaanluvsan, U. and Bernstein, L. A. and Chadwick, M. B. and Devlin, M. and Fotiades, N. and Mitchell, G. E. and et al.}, year={2007}, month={May} }
 @article{dashdorj_mitchell_becker_agvaanluvsan_bernstein_younes_garrett_chadwick_devlin_fotiades_et al._2007, title={Gamma-ray production cross sections in multiple channels for neutron-induced reaction on (48)Ti for E(n)=1 to 200 MeV}, volume={157}, ISSN={["0029-5639"]}, DOI={10.13182/NSE07-A2713}, abstractNote={Abstract Prompt γ-ray production cross sections were measured on a 48Ti sample for incident neutron energies from 1 to 200 MeV. Partial γ-ray cross sections for transitions in 45-48Ti, 45-48Sc, and 43-45Ca were determined. The observation of about 130 transitions from 11 different isotopes in the present work provides a demanding test of reaction model calculations, and is the first study in this mass region to extract partial γ-ray cross sections for many different reaction channels over a wide range of incident neutron energies. The neutrons were produced by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center/Weapons Neutron Research facility. The prompt-reaction γ rays were detected with the large-scale Compton-suppressed GErmanium Array for Neutron Induced Excitations (GEANIE). Event neutron energies were determined by the time-of-flight technique. The γ-ray excitation functions were converted to partial γ-ray cross sections and then compared with model calculations using the enhanced GNASH reaction code. Compound nuclear, preequilibrium emission, and direct reaction mechanisms are included. Overall, the model calculations of the partial γ-ray cross sections are in good agreement with measured values.}, number={1}, journal={NUCLEAR SCIENCE AND ENGINEERING}, author={Dashdorj, D. and Mitchell, G. E. and Becker, J. A. and Agvaanluvsan, U. and Bernstein, L. A. and Younes, W. and Garrett, P. E. and Chadwick, M. B. and Devlin, M. and Fotiades, N. and et al.}, year={2007}, month={Sep}, pages={65–77} }
 @article{dashdorj_mitchell_kawano_becker_agvaanluvsan_chadwick_cooper_devlin_fotiades_garrett_et al._2007, title={Neutron induced inelastic cross-sections of Sm-150 for E-n=1-35 MeV}, volume={261}, ISSN={["1872-9584"]}, DOI={10.1016/j.nimb.2007.04.161}, abstractNote={Cross-section measurements were made of prompt γ-ray production as a function of incident neutron energy (En = 1–35 MeV) on an enriched (95.6%) l50Sm sample. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the Los Alamos Neutron Science Center (LANSCE) facility. The prompt-reaction γ-rays were detected with the large-scale Compton-suppressed germanium array for neutron induced excitations (GEANIE). Neutron energies were determined by the time-of-flight technique. The γ-ray excitation functions were converted to partial γ-ray cross-sections taking into account the dead-time correction, target thickness, detector efficiency and neutron flux (monitored with an in-line fission chamber). Partial γ-ray cross-sections were predicted using the Hauser–Feshbach statistical reaction code GNASH. Above En ∼ 8 MeV, the pre-equilibrium reaction process dominates the inelastic reaction. The spin-distribution transferred in pre-equilibrium neutron induced reactions was calculated using the quantum mechanical theory of Feshbach, Kerman and Koonin (FKK). These pre-equilibrium spin distributions were incorporated into a new version of GNASH and the γ-ray production cross-sections were calculated and compared with experimental data. The difference in the partial γ-ray cross-sections using spin-distributions with and without pre-equilibrium effects is discussed.}, number={1-2}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Dashdorj, D. and Mitchell, G. E. and Kawano, T. and Becker, J. A. and Agvaanluvsan, U. and Chadwick, M. B. and Cooper, J. R. and Devlin, M. and Fotiades, N. and Garrett, P. E. and et al.}, year={2007}, month={Aug}, pages={948–952} }
 @article{sheets_agvaanluvsan_becker_becvar_bredeweg_haight_krticka_jandel_mitchell_o'donnell_et al._2007, title={Spin and parity assignments for Mo-94,Mo-95 neutron resonances}, volume={76}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.76.064317}, abstractNote={The {gamma} rays following the {sup 94,95}Mo(n,{gamma}) reactions were measured as a function of incident neutron energy by the time-of-flight method with the DANCE (Detector for Advanced Neutron Capture Experiments) array of 160 BaF{sub 2} scintillation detectors at the Los Alamos Neutron Science Center. The targets were enriched samples: 91.59% {sup 94}Mo and 96.47% {sup 95}Mo. The {gamma}-ray multiplicities and energy spectra for different multiplicities were measured in s- and p-wave resonances up to E{sub n}=10 keV for {sup 94}Mo and up to E{sub n}=2 keV for {sup 95}Mo. Definite spins and parities were assigned in {sup 96}Mo for about 60% of the resonances, and tentative spins and parities were assigned for the remaining resonances. In {sup 95}Mo the parities were determined for the observed resonances, confirming previously known assignments.}, number={6}, journal={PHYSICAL REVIEW C}, author={Sheets, S. A. and Agvaanluvsan, U. and Becker, J. A. and Becvar, F. and Bredeweg, T. A. and Haight, R. C. and Krticka, M. and Jandel, M. and Mitchell, G. E. and O'Donnell, J. M. and et al.}, year={2007}, month={Dec} }
 @article{kaneko_hasegawa_agvaanluvsan_algin_chankova_guttormsen_larsen_mitchell_rekstad_schiller_et al._2006, title={Breaking of nucleon Cooper pairs at finite temperature in Mo93-98}, volume={74}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.74.024325}, abstractNote={The S shape of the canonical heat-capacity curve is known as a signature of the pairing transition, and along an isotopic chain it is significantly more pronounced for nuclei with an even number of neutrons than for those with an odd number. Although the heat capacities extracted from experimental level densities in {sup 93-98}Mo exhibit a clear S shape, they do not show such an odd-even staggering. To understand the underlying physics, we analyze thermal quantities evaluated from the partition function calculated using the static-path plus random-phase approximation (SPA+RPA) in a monopole pairing model with number-parity projection. The calculated level densities reproduce very well the experimental data, and they also agree with estimates made using the back-shifted Fermi-gas model. We clarify the reason why the heat capacities for Mo isotopes do not show odd-even staggering of the S shape. We also discuss thermal odd-even mass differences in {sup 94-97}Mo that were calculated using the three-, four-, and five-point formulas. These thermal mass differences are regarded as indicators of pairing correlations at finite temperature.}, number={2}, journal={PHYSICAL REVIEW C}, author={Kaneko, K. and Hasegawa, M. and Agvaanluvsan, U. and Algin, E. and Chankova, R. and Guttormsen, M. and Larsen, A. C. and Mitchell, G. E. and Rekstad, J. and Schiller, A. and et al.}, year={2006}, month={Aug} }
 @article{chankova_schiller_agvaanluvsan_algin_bernstein_guttormsen_ingebretsen_lonnroth_messelt_mitchell_et al._2006, title={Level densities and thermodynamical quantities of heated Mo93-98 isotopes}, volume={73}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.73.034311}, abstractNote={Level densities for {sup 93-98}Mo have been extracted using the ({sup 3}He,{alpha}{gamma}) and ({sup 3}He,{sup 3}He{sup '}{gamma}) reactions. From the level densities thermodynamical quantities such as temperature and heat capacity can be deduced. Data have been analyzed by utilizing both the microcanonical and the canonical ensemble. Structures in the microcanonical temperature are consistent with the breaking of nucleon Cooper pairs. The S shape of the heat capacity curves found within the canonical ensemble is interpreted as consistent with a pairing phase transition with a critical temperature for the quenching of pairing correlations at T{sub c}{approx}0.7-1.0MeV.}, number={3}, journal={PHYSICAL REVIEW C}, author={Chankova, R and Schiller, A and Agvaanluvsan, U and Algin, E and Bernstein, LA and Guttormsen, M and Ingebretsen, F and Lonnroth, T and Messelt, S and Mitchell, GE and et al.}, year={2006}, month={Mar} }
 @article{voinov_grimes_agvaanluvsan_algin_belgya_brune_guttormsen_hornish_massey_mitchell_et al._2006, title={Level density of Fe-56 and low-energy enhancement of gamma-strength function}, volume={74}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.74.014314}, abstractNote={The $^{55}$Mn$(d,n)^{56}$Fe differential cross section is measured at $E_d=7$ MeV\@. The $^{56}$Fe level density obtained from neutron evaporation spectra is compared to the level density extracted from the $^{57}$Fe$(^3$He,$\alpha\gamma)^{56}$Fe reaction by the Oslo-type technique. Good agreement is found between the level densities determined by the two methods. With the level density function obtained from the neutron evaporation spectra, the $^{56}$Fe $\gamma$-strength function is also determined from the first-generation $\gamma$ matrix of the Oslo experiment. The good agreement between the past and present results for the $\gamma$-strength function supports the validity of both methods and is consistent with the low-energy enhancement of the $\gamma$ strength below $\sim 4$ MeV first discovered by the Oslo method in iron and molybdenum isotopes.}, number={1}, journal={PHYSICAL REVIEW C}, author={Voinov, A. V. and Grimes, S. M. and Agvaanluvsan, U. and Algin, E. and Belgya, T. and Brune, C. R. and Guttormsen, M. and Hornish, M. J. and Massey, T. and Mitchell, G. E. and et al.}, year={2006}, month={Jul} }
 @article{mitchell_furman_lychagin_muzichka_nekhaev_strelkov_sharapov_shvetsov_levakov_litvin_et al._2005, title={A direct measurement of the neutron-neutron scattering length}, volume={35}, ISSN={["0103-9733"]}, DOI={10.1590/S0103-97332005000500036}, abstractNote={A direct measurement of nn-scattering by colliding free neutrons has never been performed. Indirect measurements continue to provide inconsistent results, leaving the issue of charge symmetry in the nuclear force unresolved. At present the Russian pulsed reactor YAGUAR is the best neutron source for such a measurement. A neutron moderator is installed in the central through channel and the scattered neutrons are detected at a distance of 12 m from the reactor. An instantaneous value of 1.1 × 1018/cm2s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as ISTC project No. 2286.}, number={3B}, journal={BRAZILIAN JOURNAL OF PHYSICS}, author={Mitchell, GE and Furman, WI and Lychagin, EV and Muzichka, AY and Nekhaev, GV and Strelkov, AV and Sharapov, EI and Shvetsov, VN and Levakov, BG and Litvin, VI and et al.}, year={2005}, month={Sep}, pages={850–853} }
 @article{davis_gould_mitchell_sharapov_2005, title={Bounds on time reversal violation from polarized neutron capture with unpolarized targets}, volume={110}, ISSN={1044-677X}, url={http://dx.doi.org/10.6028/jres.110.075}, DOI={10.6028/jres.110.075}, abstractNote={We have analyzed constraints on parity-odd time-reversal noninvariant interactions derived from measurements of the energy dependence of parity-violating polarized neutron capture on unpolarized targets. As previous authors found, a perturbation in energy dependence due to a parity (P)-odd time (T)-odd interaction is present. However, the perturbation competes with T-even terms which can obscure the T-odd signature. We estimate the magnitudes of these competing terms and suggest strategies for a practicable experiment.}, number={4}, journal={Journal of Research of the National Institute of Standards and Technology}, publisher={National Institute of Standards and Technology (NIST)}, author={Davis, E.D. and Gould, C.R. and Mitchell, G.E. and Sharapov, E.I.}, year={2005}, month={Jul}, pages={485} }
 @article{crawford_furman_howell_lychagin_levakov_litvin_lyzhin_magda_mitchell_muzichka_et al._2005, title={Direct nn-scattering at the YAGUAR reactor}, volume={241}, ISSN={["0168-583X"]}, DOI={10.1016/j.nimb.2005.07.023}, abstractNote={The Direct Investigation of ann Association (DIANNA) is finalizing the design of a direct measurement of the nn-scattering length to be performed at the YAGUAR reactor in Snezhinsk, Russia. Extensive modeling of the neutron field, nn-scattering kinematics, and sources of detector background have verified the plan for a 3% measurement of ann. Measurements of the neutron flux support the neutron field modeling. Initial test measurements of the neutron field inside the underground channel have confirmed calculations of the thermal neutron background.}, number={1-4}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Crawford, BE and Furman, WI and Howell, CR and Lychagin, EV and Levakov, BG and Litvin, VI and Lyzhin, AE and Magda, EP and Mitchell, GE and Muzichka, AY and et al.}, year={2005}, month={Dec}, pages={190–194} }
 @article{mitchell_furman_lychagin_muzichka_nekhaev_strelkov_sharapov_shvetsov_chernuhin_levakov_et al._2005, title={Direct nn-scattering measurement with the pulsed reactor YAGUAR}, volume={110}, ISSN={["1044-677X"]}, DOI={10.6028/jres.110.029}, abstractNote={Although crucial for resolving the issue of charge symmetry in the nuclear force, direct measurement of nn-scattering by colliding free neutrons has never been performed. At present the Russian pulsed reactor YAGUAR is the best neutron source for performing such a measurement. It has a through channel where the neutron moderator is installed. The neutrons are counted by a neutron detector located 12 m from the reactor. In preliminary experiments an instantaneous value of 1.1 × 1018/cm2s was obtained for the thermal neutron flux density. The experiment will be performed by the DIANNA Collaboration as International Science & Technology Center (ISTC) project No. 2286.}, number={3}, journal={JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY}, author={Mitchell, GE and Furman, WI and Lychagin, EV and Muzichka, AY and Nekhaev, GV and Strelkov, AV and Sharapov, EI and Shvetsov, VN and Chernuhin, YI and Levakov, BG and et al.}, year={2005}, pages={225–230} }
 @article{agvaanluvsan_algin_becker_guttormsen_mitchell_siem_schiller_voinov_2005, title={Investigation of the radiative strength function}, volume={241}, ISSN={["0168-583X"]}, DOI={10.1016/j.nimb.2005.07.081}, abstractNote={The radiative strength function (RSF) is key for understanding nuclear reaction rates in areas ranging from astrophysics to radiochemical diagnostics. The RSF also provides a tool for understanding the characteristics of gamma-ray cascades. Unresolved transitions in nuclear deexcitation processes are best described by statistical properties such as the radiative strength function. The sequential extraction method developed at the Oslo Cyclotron Laboratory provides data for radiative strength functions for gamma-ray energies from 1 MeV to the neutron binding energy. The data are averaged over about 100 keV energy bin and normalized to the average total radiative width of neutron resonances. The radiative strength functions in all nuclei studied show a characteristic increase with increasing gamma-ray energy. However, the detailed structures in the radiative strength function for various nuclei show different behavior in various mass regions. In rare-earth nuclei, a resonance structure near 3 MeV is observed. For several lighter nuclei (A < 100), a large enhancement for low transition energies is observed. This unexpected phenomenon is not explained by existing theoretical models. Additional investigations using independent measurements are underway. The experiments and analysis methods will be described briefly. Experimental data for Fe, Sn, and Yb will be shown to illustrate the variety of behavior observed for the radiative strength function.}, number={1-4}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS}, author={Agvaanluvsan, U and Algin, E and Becker, JA and Guttormsen, M and Mitchell, GE and Siem, S and Schiller, A and Voinov, A}, year={2005}, month={Dec}, pages={180–184} }
 @article{guttormsen_chankova_agvaanluvsan_algin_bernstein_ingebretsen_lonnroth_messelt_mitchell_rekstad_et al._2005, title={Radiative strength functions in Mo93-98}, volume={71}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.71.044307}, abstractNote={Radiative strength functions (RSFs) in 93-98Mo have been extracted using the (3He,alpha gamma) and (3He,3He' gamma) reactions. The RSFs are U-shaped as function of gamma energy with a minimum at around E_gamma=3 MeV. The minimum values increase with neutron number due to the increase in the low-energy tail of the giant electric dipole resonance with nuclear deformation. The unexpected strong increase in strength below E_gamma=3 MeV, here called soft pole, is established for all 93-98Mo isotopes. The soft pole is present at all initial excitation energies in the 5-8 MeV region.}, number={4}, journal={PHYSICAL REVIEW C}, author={Guttormsen, M and Chankova, R and Agvaanluvsan, U and Algin, E and Bernstein, LA and Ingebretsen, F and Lonnroth, T and Messelt, S and Mitchell, GE and Rekstad, J and et al.}, year={2005}, month={Apr} }
 @article{siem_agavaanluvsan_mitchell_al._2005, title={Soft resonances in hot nuclei}, volume={36}, number={4}, journal={Acta Physica Polonica. B}, author={Siem, S. and Agavaanluvsan, U. and Mitchell, G. and al.}, year={2005}, pages={1089–1093} }
 @article{shriner_mitchell_brown_2005, title={Statistical properties and broken symmetries within the shell model}, volume={71}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.71.024313}, abstractNote={Shell-model calculations in the $s\ensuremath{-}d$ shell have been utilized to examine how the statistical behavior of eigenvalues and reduced transition probabilities are affected by broken isospin symmetry. Calculations have been performed for the nuclides $^{22}\mathrm{Na},^{26}\mathrm{Al}$, and $^{34}\mathrm{Cl}$ and have been compared to existing experimental data for $^{26}\mathrm{Al}$ and $^{30}\mathrm{P}$. The eigenvalue statistics depend on the magnitude of the Coulomb matrix element, and this is reflected in a sensitivity to the choice of single-particle energies. The distributions of reduced transition probabilities are not universal but depend upon the particular transition mode chosen; this behavior is qualitatively similar to experimental results.}, number={2}, journal={PHYSICAL REVIEW C}, author={Shriner, JF and Mitchell, GE and Brown, BA}, year={2005}, month={Feb} }
 @article{lokitz_mitchell_shriner_2005, title={Test of Sc-45 level densities with proton resonances}, volume={71}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.71.064315}, abstractNote={A high resolution measurement of the cross sections of the {sup 44}Ca(p,p{sub 0}) and {sup 44}Ca(p,p{sub 1}) reactions was performed over the energy range E{sub p}=2.50-3.53 MeV. A total of 809 resonances were observed. The purity and completeness of the {sup 45}Sc data were tested with a variety of statistical analyses. These analyses suggest that the 1/2{sup +} and 1/2{sup -} resonance sequences are the most pure and complete ever measured. The resulting level densities are {rho}(1/2){sup +}=127{sub -8}{sup +7} MeV{sup -1} and {rho}(1/2{sup -})=132{sub -9}{sup +8} MeV{sup -1}; there is no evidence of parity dependence of the level density of J=1/2 states at E{sub x}=10 MeV in {sup 45}Sc.}, number={6}, journal={PHYSICAL REVIEW C}, author={Lokitz, SJ and Mitchell, GE and Shriner, JF}, year={2005}, month={Jun} }
 @article{davis_gould_mitchell_sharapov_2004, title={Bounds on P-odd T-odd interactions from polarized neutron capture with unpolarized targets}, volume={69}, ISSN={0556-2813 1089-490X}, url={http://dx.doi.org/10.1103/physrevc.69.015501}, DOI={10.1103/physrevc.69.015501}, abstractNote={We expand on an interesting proposal (by Flambaum and Sushkov) to constrain parity-odd time-reversal noninvariant interactions with measurements of the energy dependence of parity-violating polarized neutron capture on unpolarized targets. We show that the perturbation in energy dependence due a P-odd T-odd interaction is obscured by terms due to electroweak effects. We evaluate for a practicable experiment the influence of these terms on the locations of zeros in a parity-violating asymmetry. Measurements which succeed in putting limits on these shifts of slightly more than the 1 meV or so that we estimate them to be, would constrain the ratio of the rms value of compound nucleus matrix elements of any P-odd T-odd nucleonnucleon interaction to the rms value of compound nucleus matrix elements of the P-odd nucleon-nucleon interaction to be less than of order of 10 ˛2 .}, number={1}, journal={Physical Review C}, publisher={American Physical Society (APS)}, author={Davis, E. D. and Gould, C. R. and Mitchell, G. E. and Sharapov, E. I.}, year={2004}, month={Jan} }
 @article{crawford_stephenson_howell_mitchell_tornow_furman_lychagin_muzichka_nekhaev_strelkov_et al._2004, title={Calculations of neutron spectra after neutron-neutron scattering}, volume={30}, ISSN={["0954-3899"]}, DOI={10.1088/0954-3899/30/9/024}, abstractNote={A direct neutron–neutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the proton–proton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum—Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal–thermal and thermal–epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.}, number={9}, journal={JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS}, author={Crawford, BE and Stephenson, SL and Howell, CR and Mitchell, GE and Tornow, W and Furman, WI and Lychagin, EV and Muzichka, AY and Nekhaev, GV and Strelkov, AV and et al.}, year={2004}, month={Sep}, pages={1269–1285} }
 @article{shriner_mitchell_brown_2004, title={Isospin symmetry breaking and the nuclear shell model}, volume={586}, ISSN={["1873-2445"]}, DOI={10.1016/j.physletb.2004.02.062}, abstractNote={Abstract The effect of isospin symmetry breaking on level statistics has been examined with the nuclear shell model. The eigenvalues and electromagnetic transitions were calculated with the program OXBASH for the nuclide 26 Al for conserved isospin and for broken isospin. The long-range correlations of the eigenvalues, as measured by Δ 3 , show good agreement between the experimental results and the calculations. However, there are discrepancies between data and calculations for the short-range correlations of the eigenvalues.}, number={3-4}, journal={PHYSICS LETTERS B}, author={Shriner, JF and Mitchell, GE and Brown, BA}, year={2004}, month={Apr}, pages={232–238} }
 @article{aberg_heine_mitchell_richter_2004, title={Isospin symmetry brealdng in Tc-93 and statistical properties}, volume={598}, DOI={10.1016/j.physleth.2004.07.051}, number={02-Jan}, journal={Physics Letters. B}, author={Aberg, S. and Heine, A. and Mitchell, G. E. and Richter, A.}, year={2004}, pages={42–46} }
 @article{voinov_algin_agvaanluvsan_belgya_chankova_guttormsen_mitchell_rekstad_schiller_siem_2004, title={Large enhancement of radiative strength for soft transitions in the quasicontinuum}, volume={93}, ISSN={["1079-7114"]}, DOI={10.1103/physrevlett.93.142504}, abstractNote={Radiative strength functions (RSFs) for the (56,57)Fe nuclei below the separation energy are obtained from the 57Fe(3He,alphagamma)56Fe and 57Fe(3He,3He'gamma)57Fe reactions, respectively. An enhancement of more than a factor of 10 over common theoretical models of the soft (E(gamma) less than or approximately equal 2 MeV) RSF for transitions in the quasicontinuum (several MeV above the yrast line) is observed. Two-step cascade intensities with soft primary transitions from the 56Fe(n,2gamma)57Fe reaction confirm the enhancement.}, number={14}, journal={PHYSICAL REVIEW LETTERS}, author={Voinov, A and Algin, E and Agvaanluvsan, U and Belgya, T and Chankova, R and Guttormsen, M and Mitchell, GE and Rekstad, J and Schiller, A and Siem, S}, year={2004}, month={Oct} }
 @article{agvaanluvsan_schiller_becker_bernstein_garrett_guttormsen_mitchell_rekstad_siem_voinov_et al._2004, title={Level densities and gamma-ray strength functions in Yb-170,Yb-171,Yb-172}, volume={70}, number={5}, journal={Physical Review. C, Nuclear Physics}, author={Agvaanluvsan, U. and Schiller, A. and Becker, J. A. and Bernstein, L. A. and Garrett, P. E. and Guttormsen, M. and Mitchell, G. E. and Rekstad, J. and Siem, S. and Voinov, A. and et al.}, year={2004} }
 @article{lokitz_mitchell_shriner_2004, title={Parity dependence of Sc-45 level densities}, volume={599}, ISSN={["1873-2445"]}, DOI={10.1016/j.physletb.2004.08.039}, abstractNote={The parity dependence of nuclear level densities provides a detailed test of the predictions of level density models. Proton resonances are extremely well suited for such studies. A high-resolution measurement of resonances in the 44Ca(p, p0) and 44Ca(p, p1) reactions determined resonance parameters for ≈800 resonances. Statistical analyses to evaluate the number of missing levels and of misassignments suggest that the 1/2+ and 1/2− data sets are the most pure and complete ever obtained. The resulting level densities are ρ(1/2+)=127−8+7MeV−1 and ρ(1/2−)=132−9+8MeV−1. There is no evidence of parity dependence of J=1/2 levels at Ex≈10MeV in 45Sc.}, number={3-4}, journal={PHYSICS LETTERS B}, author={Lokitz, SJ and Mitchell, GE and Shriner, JF}, year={2004}, month={Oct}, pages={223–229} }
 @article{mitchell_shriner_2004, title={Statistical behavior and symmetry tests}, volume={34}, ISSN={["1678-4448"]}, DOI={10.1590/S0103-97332004000500023}, abstractNote={Symmetries and statistical properties in nuclei are closely related. The most striking example is the extremely large enhancement of parity violation in neutron resonances. Statistical distributions can provide information about the underlying character of nuclear properties. Level statistics and electromagnetic transition distributions have been used successfully to provide unique tests of predictions of random matrix theory.}, number={3A}, journal={BRAZILIAN JOURNAL OF PHYSICS}, author={Mitchell, GE and Shriner, JF}, year={2004}, month={Sep}, pages={796–799} }
 @article{kilcoyne_tyliszczak_steele_fakra_hitchcock_franck_anderson_harteneck_rightor_mitchell_et al._2003, title={Interferometer-controlled scanning transmission X-ray microscopes at the Advanced Light Source}, volume={10}, ISSN={["1600-5775"]}, DOI={10.1107/S0909049502017739}, abstractNote={Two new soft X-ray scanning transmission microscopes located at the Advanced Light Source (ALS) have been designed, built and commissioned. Interferometer control implemented in both microscopes allows the precise measurement of the transverse position of the zone plate relative to the sample. Long-term positional stability and compensation for transverse displacement during translations of the zone plate have been achieved. The interferometer also provides low-distortion orthogonal x, y imaging. Two different control systems have been developed: a digital control system using standard VXI components at beamline 7.0, and a custom feedback system based on PC AT boards at beamline 5.3.2. Both microscopes are diffraction limited with the resolution set by the quality of the zone plates. Periodic features with 30 nm half period can be resolved with a zone plate that has a 40 nm outermost zone width. One microscope is operating at an undulator beamline (7.0), while the other is operating at a novel dedicated bending-magnet beamline (5.3.2), which is designed specifically to illuminate the microscope. The undulator beamline provides count rates of the order of tens of MHz at high-energy resolution with photon energies of up to about 1000 eV. Although the brightness of a bending-magnet source is about four orders of magnitude smaller than that of an undulator source, photon statistics limited operation with intensities in excess of 3 MHz has been achieved at high energy resolution and high spatial resolution. The design and performance of these microscopes are described.}, number={2003 Mar}, journal={JOURNAL OF SYNCHROTRON RADIATION}, author={Kilcoyne, ALD and Tyliszczak, T and Steele, WF and Fakra, S and Hitchcock, P and Franck, K and Anderson, E and Harteneck, B and Rightor, EG and Mitchell, GE and et al.}, year={2003}, month={Mar}, pages={125–136} }
 @article{schiller_algin_bernstein_garrett_guttormsen_hjorth-jensen_johnson_mitchell_rekstad_siem_et al._2003, title={Level densities in Fe-56,Fe-57 and Mo-96,Mo-97}, volume={68}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.68.054326}, abstractNote={Level densities have been extracted from primary gamma spectra for 56,57-Fe and 96,97-Mo nuclei using (3-He,alpha gamma) and (3-He,3-He') reactions on 57-Fe and 97-Mo targets. The level density curves reveal step structures above the pairing gap due to the breaking of nucleon Cooper pairs. The location of the step structures in energy and their shapes arise from the interplay between single-particle energies and seniority-conserving and seniority-non-conserving interactions.}, number={5}, journal={PHYSICAL REVIEW C}, author={Schiller, A and Algin, E and Bernstein, LA and Garrett, PE and Guttormsen, M and Hjorth-Jensen, M and Johnson, CW and Mitchell, GE and Rekstad, J and Siem, S and et al.}, year={2003}, month={Nov} }
 @article{agvaanluvsan_mitchell_shriner_pato_2003, title={Missing level corrections in nuclear resonances}, volume={498}, ISSN={["1872-9576"]}, DOI={10.1016/S0168-9002(02)02144-7}, abstractNote={Neutron and proton resonances provide detailed level density information. Due to experimental limitations some fraction of the resonances are not observed, and this missing fraction must be determined. The standard correction for missing levels uses the experimental widths and the Porter–Thomas distribution. Analysis of the spacing distribution should yield equivalent information. A general expression for an imperfect spacing distribution (with a fraction of levels randomly missing) was obtained with the maximum entropy principle. This formulation was tested extensively with numerical data and then applied to proton and neutron resonance data sets. Since in Random Matrix Theory the widths and spacings are not correlated, this method complements the conventional approach that considers only the widths. The two analysis methods are compared.}, number={1-3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Agvaanluvsan, U and Mitchell, GE and Shriner, JF and Pato, MP}, year={2003}, month={Feb}, pages={459–469} }
 @article{agvaanluvsan_mitchell_shriner_pato_2003, title={Parity dependence of nuclear level densities}, volume={67}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.67.064608}, abstractNote={High resolution proton resonance data have been examined for a possible parity dependence of nuclear level densities. Five spin-parity ${\mathrm{combinations}\mathrm{---}1/2}^{+},$ ${1/2}^{\ensuremath{-}},$ ${3/2}^{\ensuremath{-}},$ ${3/2}^{+},$ and ${5/2}^{+}$---have been analyzed for three ${\mathrm{datasets}\mathrm{---}}^{44}\mathrm{Ca}(p,p),$ ${}^{48}\mathrm{Ti}(p,p),$ and ${}^{56}\mathrm{Fe}(p,p).$ Much of the uncertainty in the level density arises from the determination of the fraction of levels that are not observed. The missing fraction of levels was determined by (a) the standard width analysis method that assumes a Porter-Thomas distribution for the reduced widths and (b) a recently developed method that analyzes the spacing distribution and assumes the Wigner distribution for the nearest-neighbor spacings. There are indications of parity dependence of the level densities for several of the spin-parity combinations.}, number={6}, journal={PHYSICAL REVIEW C}, author={Agvaanluvsan, U and Mitchell, GE and Shriner, JF and Pato, M}, year={2003}, month={Jun} }
 @article{furman_lychagin_muzichka_nekhaev_safronov_strelkov_sharapov_shvetsov_levakov_litvin_et al._2002, title={Direct measurement of the neutron-neutron scattering cross section at the reactor YAGUAR}, volume={28}, ISSN={["0954-3899"]}, DOI={10.1088/0954-3899/28/10/308}, abstractNote={We propose to perform the first measurement of the neutron–neutron scattering cross section in the through-channel of the pulsed aperiodic reactor YAGUAR (Snezhinsk, Russia). Such a measurement directly determines the neutron–neutron scattering length, and by comparison with the proton–proton scattering length bears upon the issue of charge symmetry of the nuclear force. The proposed experimental set-up, as well as modelling of the neutron density and of the frequency of neutron–neutron collisions is described. Experimental results are reported on the formation and optimization of the thermal neutron field inside the through-channel of the reactor YAGUAR. The instantaneous value of 1.1 × 1018 cm−2 s−1 obtained for the thermal neutron flux density is large enough to perform the first direct neutron–neutron scattering length measurement.}, number={10}, journal={JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS}, author={Furman, WI and Lychagin, EV and Muzichka, AY and Nekhaev, GV and Safronov, YV and Strelkov, AV and Sharapov, EI and Shvetsov, VN and Levakov, BG and Litvin, VI and et al.}, year={2002}, month={Oct}, pages={2627–2641} }
 @article{smith_bowman_crawford_grossmann_haseyama_masaike_matsuda_mitchell_penttila_roberson_et al._2002, title={Neutron resonance spectroscopy of Pd-104, Pd-105, and Pd-110}, volume={65}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.65.024607}, abstractNote={We have measured neutron resonances in the palladium isotopes 104, 105, and 110 for neutron energies from 1 to 2100 eV. Many new p-wave resonances have been observed. Their neutron widths and, in several cases, the radiative widths were measured. The average level spacings and the s-wave and p-wave neutron strength functions were determined. The time-of-flight method was used for both neutron total cross section measurements and total (n,γ) reaction yield measurements at the pulsed spallation neutron source of Los Alamos Neutron Science Center. Well established resonance spectroscopy for these isotopes is essential for the analysis of parity violation data that were recently measured in palladium. Disciplines Atomic, Molecular and Optical Physics | Physics Authors J D. Bowman, D A. Smith, Bret E. Crawford, T Haseyama, C A. Grossmann, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, V W. Yuan, and A M. Sukhovoj This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/7 Neutron resonance spectroscopy of Pd, Pd, and Pd D. A. Smith,* J. D. Bowman, B. E. Crawford, C. A. Grossmann, T. Haseyama, A. Masaike, Y. Matsuda, G. E. Mitchell, S. I. Penttila, N. R. Roberson, S. J. Seestrom, E. I. Sharapov, S. L. Stephenson, A. M. Sukhovoj, and V. W. Yuan Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Physics Department, Kyoto University, Kyoto 606-01, Japan Joint Institute for Nuclear Research, RU-141980 Dubna, Russia ~Received 25 August 2000; revised manuscript received 30 August 2001; published 16 January 2002! We have measured neutron resonances in the palladium isotopes 104, 105, and 110 for neutron energies from 1 to 2100 eV. Many new p-wave resonances have been observed. Their neutron widths and, in several cases, the radiative widths were measured. The average level spacings and the s-wave and p-wave neutron strength functions were determined. The time-of-flight method was used for both neutron total cross section measurements and total ~n ,g) reaction yield measurements at the pulsed spallation neutron source of Los Alamos Neutron Science Center. Well established resonance spectroscopy for these isotopes is essential for the analysis of parity violation data that were recently measured in palladium. DOI: 10.1103/PhysRevC.65.024607 PACS number~s!: 25.40.Ny, 24.80.1y, 27.60.1j}, number={2}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and Roberson, NR and et al.}, year={2002}, month={Feb} }
 @article{smith_bowman_crawford_grossmann_haseyama_masaike_matsuda_mitchell_penttila_roberson_et al._2002, title={Parity violation in neutron resonances of palladium}, volume={65}, ISSN={["2469-9993"]}, DOI={10.1103/physrevc.65.035503}, abstractNote={Parity violation in p-wave neutron resonances of the palladium isotopes 104, 105, 106, and 108 has been measured by transmission of a longitudinally polarized neutron beam through a natural palladium target. The measurements were performed at the pulsed spallation neutron source of Los Alamos Neutron Science Center. The rms weak interaction matrix elements and the corresponding spreading widths were determined for 104 Pd, 105 Pd, and 106 Pd Disciplines Atomic, Molecular and Optical Physics | Physics Authors D A. Smith, J D. Bowman, Bret E. Crawford, C A. Grossmann, T Haseyama, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/6 Parity violation in neutron resonances of palladium D. A. Smith,* J. D. Bowman, B. E. Crawford, C. A. Grossmann, T. Haseyama, A. Masaike, Y. Matsuda, G. E. Mitchell, S. I. Penttila, N. R. Roberson, S. J. Seestrom, E. I. Sharapov, S. L. Stephenson, and V. W. Yuan Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Physics Department, Kyoto University, Kyoto 606-01, Japan Joint Institute for Nuclear Research, 141980 Dubna, Russia ~Received 3 November 2001; published 4 March 2002! Parity violation in p-wave neutron resonances of the palladium isotopes 104, 105, 106, and 108 has been measured by transmission of a longitudinally polarized neutron beam through a natural palladium target. The measurements were performed at the pulsed spallation neutron source of Los Alamos Neutron Science Center. The rms weak interaction matrix elements and the corresponding spreading widths were determined for Pd, Pd, and Pd. DOI: 10.1103/PhysRevC.65.035503 PACS number~s!: 24.80.1y, 11.30.Er, 25.40.Ny, 27.60.1j}, number={3}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Masaike, A and Matsuda, Y and Mitchell, GW and Penttila, SI and Roberson, NR and et al.}, year={2002}, month={Mar} }
 @article{mitchell_wilson_dineen_urquhart_hayes_rightor_hitchcock_ade_2002, title={Quantitative characterization of microscopic variations in the cross-link density of gels}, volume={35}, ISSN={["1520-5835"]}, DOI={10.1021/ma010840d}, abstractNote={We report the visualization and quantitative analysis of the cross-link structure in model core/shell hydrogel polymers on the microscopic scale, in a fully swollen state, using soft X-ray microscopy. The cross-link density in these materials and their microscopic or even nanoscopic variation critically influence materials characteristics, yet the cross-link density is difficult to characterize by conventional methods. By the use of soft X-ray microscopy, one can investigate these materials in a fully swollen state and thus directly visualize and quantitatively determine the cross-link structure on a microscopic scale. Materials that were cross-linked by different methods were shown to give rise to differently shaped profiles. Abrupt and gradient cross-link density profiles have been investigated, and the spatial variation in their cross-link density has been determined quantitatively.}, number={4}, journal={MACROMOLECULES}, author={Mitchell, GE and Wilson, LR and Dineen, MT and Urquhart, SG and Hayes, F and Rightor, EG and Hitchcock, AP and Ade, H}, year={2002}, month={Feb}, pages={1336–1341} }
 @article{mitchell_shriner_2001, title={Effect of symmetry breaking on statistical distributions}, volume={T90}, ISSN={["1402-4896"]}, DOI={10.1238/physica.topical.090a00105}, abstractNote={The quantum numbers of states in 30P have been determined for over 100 states from the ground state to 8 MeV. Previous measurements had provided complete spectroscopy for over 150 states in 26Al in a similar energy region. These N = Z = odd nuclei have the property that states of isospin T = 0 and T = 1 coexist from the ground state. Isospin is approximately conserved in these nuclei. Since the energy E, spin J, parity π, and isospin T are known for every level, these data provide a unique opportunity to test the effect of symmetry breaking on the level statistics and on the transition strength distributions. The level statistics are strongly affected by the small symmetry breaking, in agreement with predictions of Random Matrix Theory (RMT). In 26Al the transition strength distributions differ from the standard Porter-Thomas distribution; deviations at a weaker level also appear in 30P. Until very recently there were no theoretical predictions for the effect of symmetry breaking on the transitions. Recent RMT calculations predict a deviation from the Porter-Thomas distribution, in qualitative agreement with the measurements.}, journal={PHYSICA SCRIPTA}, author={Mitchell, GE and Shriner, JF}, year={2001}, pages={105–111} }
 @article{hitchcock_koprinarov_tyliszczak_rightor_mitchell_dineen_hayes_lidy_priester_urquhart_et al._2001, title={Optimization of scanning transmission X-ray microscopy for the identification and quantitation of reinforcing particles in polyurethanes}, volume={88}, ISSN={["1879-2723"]}, DOI={10.1016/S0304-3991(00)00113-3}, abstractNote={The morphology, size distributions, spatial distributions, and quantitative chemical compositions of co-polymer polyol-reinforcing particles in a polyurethane have been investigated with scanning transmission X-ray microscopy (STXM). A detailed discussion of microscope operating procedures is presented and ways to avoid potential artifacts are discussed. Images at selected photon energies in the C 1s, N 1s and O 1s regions allow unambiguous identification of styrene-acrylonitrile-based (SAN) copolymer and polyisocyanate polyaddition product-based (PIPA) reinforcing particles down to particle sizes at the limit of the spatial resolution (50 nm). Quantitative analysis of the chemical composition of individual reinforcing particles is achieved by fitting C 1s spectra to linear combinations of reference spectra. Regression analyses of sequences of images recorded through the chemically sensitive ranges of the C 1s, N 1s and O 1s spectra are used to generate quantitative compositional maps, which provide a fast and effective means of investigating compositional distributions over a large number of reinforcing particles. The size distribution of all particles determined by STXM is shown to be similar to that determined by TEM. The size distributions of each type of reinforcing particle, which differ considerably, were obtained by analysis of STXM images at chemically selective energies.}, number={1}, journal={ULTRAMICROSCOPY}, author={Hitchcock, AP and Koprinarov, I and Tyliszczak, T and Rightor, EG and Mitchell, GE and Dineen, MT and Hayes, F and Lidy, W and Priester, RD and Urquhart, SG and et al.}, year={2001}, month={Jun}, pages={33–49} }
 @article{postma_bowman_corvi_crawford_delheij_frankle_grossmann_gunsing_haseyama_knudson_et al._2001, title={Parity violation at neutron resonances and related neutron spectroscopy experiments}, volume={51}, ISSN={["0011-4626"]}, DOI={10.1007/s10582-001-0036-2}, journal={CZECHOSLOVAK JOURNAL OF PHYSICS}, author={Postma, H and Bowman, JD and Corvi, F and Crawford, BE and Delheij, PPJ and Frankle, CM and Grossmann, CA and Gunsing, F and Haseyama, T and Knudson, JN and et al.}, year={2001}, pages={A289–A298} }
 @misc{mitchell_bowman_penttila_sharapov_2001, title={Parity violation in compound nuclei: experimental methods and recent results}, volume={354}, ISSN={["1873-6270"]}, DOI={10.1016/S0370-1573(01)00016-3}, abstractNote={The TRIPLE Collaboration studies of space-parity symmetry in the compound nucleus show numerous examples of parity violation in Br, Rh, Pd, Ag, Cd, In, Sn, Sb, I, Cs, Xe, La, U, and Th. The longitudinal cross section asymmetries have measured values in the range of 10−3–10−1 for neutron energies from several eV up to 300–2000eV, depending on the target. The high density of states leads to enhancement of the parity violation by factors as large as 106 relative to parity violation in pp scattering. The high degree of complexity of the levels permits the use of statistical methods for determination of the root mean square weak matrix element M for each nucleus. This report is focused on the experimental results of the TRIPLE Collaboration studies. Parity violation has been observed in 75 resonances of 18 nuclides. The experimental data and analysis are presented for each nuclide studied. A nonstatistical anomaly (the sign correlation effect) was observed in thorium. Statistical analysis techniques were developed and successfully applied to determine the rms weak matrix elements and the weak spreading widths Γw. The value of Γw obtained from our analysis is about 1.8×10−7eV, which is in qualitative agreement with theoretical expectations. The individual weak spreading widths are consistent with a constant or slowly varying mass dependence and there is evidence for local fluctuations.}, number={3}, journal={PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS}, author={Mitchell, GE and Bowman, JD and Penttila, SI and Sharapov, EI}, year={2001}, month={Nov}, pages={157–241} }
 @article{smith_bowman_crawford_grossmann_haseyama_johnson_masaike_matsuda_mitchell_nazarenko_et al._2001, title={Parity violation in neutron resonances of Sn-117}, volume={64}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.64.015502}, abstractNote={Parity nonconservation (PNC) was studied in p-wave neutron resonances of {sup 103}Rh in the neutron energy range 30 to 490 eV. The helicity dependence of the neutron total cross section of rhodium was determined by capture measurements with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at the Los Alamos National Laboratory. A total of 32 p-wave resonances were studied and statistically significant longitudinal asymmetries were observed for resonances at E{sub n}=44.5, 110.8, 321.6, and 432.9 eV. A statistical analysis treating the PNC matrix elements as random variables yields a weak spreading width {Gamma}{sub w}=(1.42{sub {minus}0.59}{sup +1.21}){times}10{sup {minus}7}heV. {copyright} {ital 1999} {ital The American Physical Society}}, number={1}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Johnson, MB and Masaike, A and Matsuda, Y and Mitchell, GE and Nazarenko, VA and et al.}, year={2001}, month={Jul} }
 @article{matsuda_bowman_crawford_delheij_haseyama_knudsen_lowie_masaike_masuda_mitchell_et al._2001, title={Parity violation in neutron resonances of antimony and iodine}, volume={64}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.64.015501}, abstractNote={Parity violation in p-wave neutron resonances of ${}^{121}\mathrm{Sb},$ ${}^{123}\mathrm{Sb},$ and ${}^{127}\mathrm{I}$ has been measured by transmission of a longitudinally polarized neutron beam through natural antimony and iodine targets. The measurements were performed at the pulsed spallation neutron source of the Los Alamos Neutron Science Center. Five statistically significant parity violation effects were observed in ${}^{121}\mathrm{Sb},$ one effect in ${}^{123}\mathrm{Sb},$ and seven effects in ${}^{127}\mathrm{I}.$ The weak interaction rms matrix elements and the corresponding spreading widths were determined.}, number={1}, journal={PHYSICAL REVIEW C}, author={Matsuda, Y and Bowman, JD and Crawford, BE and Delheij, PPJ and Haseyama, T and Knudsen, JN and Lowie, LY and Masaike, A and Masuda, Y and Mitchell, GE and et al.}, year={2001}, month={Jul} }
 @article{sharapov_bowman_penttila_mitchell_2001, title={Parity violation in p-wave neutron resonances}, volume={32}, number={2001}, journal={Physics of Particles and Nuclei}, author={Sharapov, E. I. and Bowman, J. D. and Penttila, S. I. and Mitchell, G. E.}, year={2001}, pages={S129–131} }
 @article{tavukcu_bernstein_hauschild_becker_garrett_mcgrath_mcnabb_younes_chadwick_nelson_et al._2001, title={Pt-196(n,x n yp gamma) reactions using spallation neutrons from E-n=1 to 250 MeV}, volume={64}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.64.054614}, number={5}, journal={PHYSICAL REVIEW C}, author={Tavukcu, E and Bernstein, LA and Hauschild, K and Becker, JA and Garrett, PE and McGrath, CA and McNabb, DP and Younes, W and Chadwick, MB and Nelson, RO and et al.}, year={2001}, month={Nov} }
 @article{mitchell_2001, title={Tests of random matrix theory in nuclei}, volume={9}, ISSN={["1873-1759"]}, DOI={10.1016/S1386-9477(00)00239-3}, abstractNote={The fluctuation properties of nuclear states and transitions are now used as a signature for chaos. We review the status of these properties in nuclei.}, number={3}, journal={PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES}, author={Mitchell, GE}, year={2001}, month={Mar}, pages={424–428} }
 @article{smith_urquhart_winesett_mitchell_ade_2001, title={Use of near edge X-ray absorption fine structure spectromicroscopy to characterize multicomponent polymeric systems}, volume={55}, DOI={10.1366/0003702011954008}, abstractNote={ The merits of a polymer characterization technique, near edge X-ray absorption fine structure (NEXAFS) spectromicroscopy, are demonstrated through the characterization of a multilayer polymer film with partially unknown chemical composition. The combination of chemical speciation through NEXAFS spectroscopy with the high spatial resolution available in X-ray microscopy allows the characterization of polymeric materials not possible with conventional techniques. Analysis of a multilayer with layers as thin as 4 μm has yielded results that differ from those previously obtained by infrared microscopy. Layers below the spatial resolution limit of infrared microscopy were characterized. }, number={12}, journal={Applied Spectroscopy}, author={Smith, A. P. and Urquhart, S. G. and Winesett, D. A. and Mitchell, G. and Ade, Harald}, year={2001}, pages={1676–1681} }
 @article{yen_bowman_bolton_crawford_delheij_hart_haseyama_frankle_iinuma_knudson_et al._2000, title={A high-rate (10)B-loaded liquid scintillation detector for parity-violation studies in neutron resonances}, volume={447}, ISSN={["0168-9002"]}, DOI={10.1016/S0168-9002(99)01308-X}, abstractNote={We have developed a large-area 10B-loaded liquid scintillation detector for parity-violation studies in neutron resonances with high instantaneous neutron fluxes from the LANSCE short-pulse spallation source. The detector has an efficiency of 95%, 85% and 71% at neutron energies of 10, 100 and 1000 eV, respectively. The neutron mean capture time in the detector is (416±5)ns. We describe the detector and the current-mode signal processing system, that can handle neutron rates up to 500 MHz.}, number={3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Yen, YF and Bowman, JD and Bolton, RD and Crawford, BE and Delheij, PPJ and Hart, GW and Haseyama, T and Frankle, CM and Iinuma, M and Knudson, JN and et al.}, year={2000}, month={Jun}, pages={476–489} }
 @inbook{mitchell_wilson_rightor_dineen_hayes_urquhart_hitchcock_ade_2000, title={Characterization of microscopic variation in crosslink density in polymer gels using scanning transmission X-ray microscopy}, volume={165}, ISBN={0750306858}, number={2000}, booktitle={Microbeam Analysis 2000: proceedings of the Second Conference of the International Union of Microbeam Analysis Societies held in Kailua-Kona, Hawaii, 9-14 July 2000}, publisher={Bristol: Institute of Physics Publishing}, author={Mitchell, G. and Wilson, L. R. and Rightor, E. G. and Dineen, M. T. and Hayes, F. and Urquhart, S. and Hitchcock, A. and Ade, H.}, editor={Williams, D. B. and Shimizu, R.Editors}, year={2000}, pages={113–114} }
 @article{grossmann_labonte_mitchell_shriner_shriner_vavrina_wallace_2000, title={Complete spectroscopy of P-30}, volume={62}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.62.024323}, abstractNote={The {sup 29}Si(p,{gamma}){sup 30}P reaction was studied for 32 resonances in the energy range E{sub p}=1.0-2.5 MeV. Angular distributions were measured for 230 primary and secondary transitions. Results from the analysis of these data were combined with previous measurements of the {sup 29}Si(p,p{sub 0}){sup 29}Si and {sup 29}Si(p,{gamma}){sup 30}P reactions to determine the spin J, parity {pi}, and isospin T of many levels. Remaining ambiguities were eliminated by comparison with the spectrum of the parent nucleus {sup 30}Si and with the calculated shell-model spectrum. J, {pi}, and T have been assigned for 103 states up to an excitation energy of 8.0 MeV. (c) 2000 The American Physical Society.}, number={2}, journal={PHYSICAL REVIEW C}, author={Grossmann, CA and LaBonte, MA and Mitchell, GE and Shriner, JD and Shriner, JF and Vavrina, GA and Wallace, PM}, year={2000}, month={Aug} }
 @article{shriner_grossmann_mitchell_2000, title={Level statistics and transition distributions of P-30}, volume={62}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.62.054305}, abstractNote={Level statistics and reduced transition probability distributions have been analyzed over the region E{sub x}=0--8014keV in {sup 30}P and compared to previous results from {sup 26}Al. The level statistics in {sup 30}P show clear evidence of broken isospin symmetry and are very similar to those from {sup 26}Al. Transition distributions in the two nuclides are different, but both suggest that the broken symmetry also affects the transitions.}, number={5}, journal={PHYSICAL REVIEW C}, author={Shriner, JF and Grossmann, CA and Mitchell, GE}, year={2000}, month={Nov} }
 @article{mitchell_bowman_crawford_delheij_frankle_iinuma_knudson_lowie_masaike_matsuda_et al._2000, title={New search for parity violation in nonresonant neutron scattering on thorium}, volume={61}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.61.045503}, abstractNote={The parity-violating longitudinal asymmetry of the neutron scattering cross section has been measured for thorium in the off-resonance energy intervals from 30 to 300 eV. The observed result of $(0.5\ifmmode\pm\else\textpm\fi{}1.6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ is compared with theoretical predictions.}, number={4}, journal={PHYSICAL REVIEW C}, author={Mitchell, GE and Bowman, JD and Crawford, BE and Delheij, PPJ and Frankle, CM and Iinuma, M and Knudson, JN and Lowie, LY and Masaike, A and Matsuda, Y and et al.}, year={2000}, month={Apr} }
 @article{sharapov_bowman_crawford_delheij_frankle_iinuma_knudson_lowie_lynch_masaike_et al._2000, title={Parity violation in Th-232 neutron resonances above 250 eV}, volume={61}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.61.025501}, abstractNote={The analysis of parity nonconservation (PNC) measurements performed on {sup 232}Th by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar analysis was performed on the data below 250 eV, for which longitudinal asymmetries were obtained previously. For energies below 250 eV, the p-wave neutron strength functions for the J=1/2 and J=3/2 states were extracted: S{sub 1/2}{sup 1}=(1.68{+-}0.61)x10{sup -4} and S{sub 3/2}{sup 1}=(0.75{+-}0.18)x10{sup -4}. The data provide constraints on the properties of local doorway states proposed to explain the PNC sign effect in thorium. (c) 2000 The American Physical Society.}, number={2}, journal={PHYSICAL REVIEW C}, author={Sharapov, EI and Bowman, JD and Crawford, BE and Delheij, PPJ and Frankle, CM and Iinuma, M and Knudson, JN and Lowie, LY and Lynch, JE and Masaike, A and et al.}, year={2000}, month={Feb} }
 @article{stephenson_bowman_corvi_crawford_delheij_frankle_iinuma_knudson_lowie_masaike_et al._2000, title={Parity violation in neutron resonances in In-115}, volume={61}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.61.045501}, abstractNote={Parity nonconservation (PNC) was studied in p-wave resonances in indium by measuring the helicity dependence of the neutron total cross section in the neutron energy range 6.0-316 eV with the time-of-flight method at LANSCE. A total of 36 p-wave neutron resonances were studied in {sup 115}In, and statistically significant asymmetries were observed for nine cases. An analysis treating the PNC matrix elements as random variables yields a weak matrix element of M=(0.67{sub -0.12}{sup +0.16}) meV and a weak spreading width of {gamma}{sub w}=(1.30{sub -0.43}{sup +0.76})x10{sup -7} eV. (c) 2000 The American Physical Society.}, number={4}, journal={PHYSICAL REVIEW C}, author={Stephenson, SL and Bowman, JD and Corvi, F and Crawford, BE and Delheij, PPJ and Frankle, CM and Iinuma, M and Knudson, JN and Lowie, LY and Masaike, A and et al.}, year={2000}, month={Apr} }
 @inbook{rightor_urquhart_hitchcock_ade_mitchell_dineen_hayes_priester_lidy_2000, title={Segregated phases in flexible polyurethanes by x-ray spectromicroscopy}, volume={165}, ISBN={0750306858}, number={2000}, booktitle={Microbeam Analysis 2000: proceedings of the Second Conference of the International Union of Microbeam Analysis Societies held in Kailua-Kona, Hawaii, 9-14 July 2000}, publisher={Bristol: Institute of Physics Publishing}, author={Rightor, E. and Urquhart, S. and Hitchcock, A. and Ade, H. and Mitchell, G. and Dineen, M. T. and Hayes, F. and Priester, R. and Lidy, W.}, editor={Williams, D. B. and Shimizu, R.Editors}, year={2000}, pages={111–112} }
 @article{urquhart_hitchcock_smith_ade_lidy_rightor_mitchell_1999, title={NEXAFS spectromicroscopy of polymers: overview and quantitative analysis of polyurethane polymers}, volume={100}, ISSN={["1873-2526"]}, DOI={10.1016/S0368-2048(99)00043-2}, abstractNote={The successful application of X-ray spectromicroscopy to chemical analysis of polymers is reviewed and a detailed application to quantitative analysis of polyurethanes is presented. Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy is the basis of chemical sensitive X-ray imaging, as well as qualitative and quantitative micro-spectroscopy. These capabilities are demonstrated by a review of recent work, and by presentation of new results outlining a methodology for quantitative speciation of polyurethane polymers. C 1s inner-shell excitation spectra of a series of molecular and polymeric model compounds, recorded by gas phase inelastic electron scattering (ISEELS) and solid phase NEXAFS techniques, are used to understand the spectroscopic basis for chemical analysis of polyurethanes. These model species contain the aromatic urea, aromatic urethane (carbamate) and aliphatic ether functionalities that are the main constituents of polyurethane polymers. Ab initio calculations of several of the model molecular compounds are used to support spectral assignments and give insight into the origin and relative intensities of characteristic spectral features. The model polymer spectra provide reference standards for qualitative identification and quantitative analysis of polyurethane polymers. The chemical compositions of three polyurethane test polymers with systematic variation in urea/urethane content are measured using the spectra of model toluene diisocyanate (TDI) urea, TDI-carbamate, and poly(propylene oxide) polymers as reference standards.}, number={1999 Oct.}, journal={JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA}, author={Urquhart, SG and Hitchcock, AP and Smith, AP and Ade, HW and Lidy, W and Rightor, EG and Mitchell, GE}, year={1999}, month={Oct}, pages={119–135} }
 @article{smith_bowman_crawford_grossmann_haseyama_masaike_matsuda_mitchell_penttila_roberson_et al._1999, title={Neutron resonance spectroscopy of Rh-103 from 30 eV to 2 keV}, volume={60}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.60.045502}, abstractNote={Neutron resonances in {sup 103}Rh have been measured for neutron energies from 30 to 2000 eV using the time-of-flight method and the (n,{gamma}) reaction. The rhodium resonance spectroscopy is essential for the analysis of parity violation measurements recently performed on neutron resonances in {sup 103}Rh. Neutron scattering and radiative widths were determined, and orbital angular momentum assignments made with a Bayesian analysis. The s-wave and p-wave strength functions and average level spacings were determined. {copyright} {ital 1999} {ital The American Physical Society}}, number={4}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and Roberson, NR and et al.}, year={1999}, month={Oct} }
 @article{smith_bowman_crawford_grossmann_haseyama_johnson_masaike_matsuda_mitchell_nazarenko_et al._1999, title={Neutron resonance spectroscopy of Sn-117 from 1 eV to 1.5 keV}, volume={59}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.59.2836}, abstractNote={Parity violation has been studied recently for neutron resonances in {sup 117}Sn. The neutron resonance spectroscopy is essential for the analysis of the parity violation data. We have measured neutron resonances in {sup 117}Sn for neutron energies from 1 to 1500 eV using the time-of-flight method and the (n,{gamma}) reaction. The sample was enriched to 87.6{percent} {sup 117}Sn. Neutron scattering and radiative widths were determined, and orbital angular momentum assignments were made with a Bayesian analysis. The {ital s}-wave and {ital p}-wave strength functions and average level spacings were determined. {copyright} {ital 1999} {ital The American Physical Society}}, number={5}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Johnson, MB and Masaike, A and Matsuda, Y and Mitchell, GE and Nazarenko, VA and et al.}, year={1999}, month={May}, pages={2836–2843} }
 @article{crawford_bowman_delheij_haseyama_knudson_lowie_masaike_matsuda_mitchell_penttila_et al._1999, title={Parity nonconservation in Pd-106 and Pd-108 neutron}, volume={60}, ISSN={["2469-9993"]}, DOI={10.1103/physrevc.60.055503}, abstractNote={Parity nonconservation (PNC) has been studied in the neutron {ital p}-wave resonances of {sup 106}Pd and {sup 108}Pd in the energy range of 20 to 2000 eV. Longitudinal asymmetries in {ital p}-wave capture cross sections are measured using longitudinally polarized neutrons incident on {approximately}20-g metal-powder targets at LANSCE. A CsI {gamma}-ray detector array measures capture cross section asymmetries as a function of neutron energy which is determined by the neutron time-of-flight method. A total of 21 {ital p}-wave resonances in {sup 106}Pd and 21 {ital p}-wave resonances in {sup 108}Pd were studied. One statistically significant PNC effect was observed in {sup 106}Pd, and no effects were observed in {sup 108}Pd. For {sup 106}Pd a weak spreading width of {Gamma}{sub w}=34{sub {minus}28}{sup +47}{times}10{sup {minus}7} eV was obtained. For {sup 108}Pd an upper limit on the weak spreading width of {Gamma}{sub w}{lt}12{times}10{sup {minus}7} eV was determined at the 68{percent} confidence level. {copyright} {ital 1999} {ital The American Physical Society}}, number={5}, journal={PHYSICAL REVIEW C}, author={Crawford, BE and Bowman, JD and Delheij, PPJ and Haseyama, T and Knudson, JN and Lowie, LY and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and et al.}, year={1999}, month={Nov} }
 @article{sharapov_bowman_crawford_delheij_haseyama_knudson_lowie_masaike_masuda_matsuda_et al._1999, title={Parity nonconservation in neutron resonances in Cs-133}, volume={59}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.59.1772}, abstractNote={Spatial parity nonconservation (PNC) has been studied in the compound-nuclear states of 134Cs by measuring the helicity dependence of the neutron total cross section. Transmission measurements on a thick 133Cs target were performed by the time-of-flight method at the Manuel Lujan Neutron Scattering Center with a longitudinally polarized neutron beam in the energy range from 5 to 400 eV. A total of 28 new p-wave resonances were found, their neutron widths determined, and the PNC longitudinal asymmetries of the resonance cross sections measured. The value obtained for the root-mean-square PNC element M=(0.06-0.02+0.25) meV in 133Cs is the smallest among all targets studied. This value corresponds to a weak spreading width Γw=(0.006-0.003+0.154)×10-7 eV. Disciplines Atomic, Molecular and Optical Physics | Physics Authors E I. Sharapov, J D. Bowman, Bret E. Crawford, P P J. Delheij, T Haseyama, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, Sharon L. Stephenson, Y-F Yen, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/17 Parity nonconservation in neutron resonances in Cs E. I. Sharapov, J. D. Bowman, B. E. Crawford,* P. P. J. Delheij, T. Haseyama, J. N. Knudson, L. Y. Lowie, A. Masaike, Y. Masuda, Y. Matsuda, G. E. Mitchell, S. I. Penttila, H. Postma, N. R. Roberson, S. J. Seestrom, S. L. Stephenson, Y.-F. Yen, and V. W. Yuan Joint Institute for Nuclear Research, 141980 Dubna, Russia Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 Physics Department, Kyoto University, Kyoto 606-01, Japan North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 National Laboratory of High Energy Physics, Tsukuba-shi, 305, Japan Delft University of Technology, Delft, 2600 GA, The Netherlands ~Received 19 October 1998! Spatial parity nonconservation ~PNC! has been studied in the compound-nuclear states of Cs by measuring the helicity dependence of the neutron total cross section. Transmission measurements on a thick Cs target were performed by the time-of-flight method at the Manuel Lujan Neutron Scattering Center with a longitudinally polarized neutron beam in the energy range from 5 to 400 eV. A total of 28 new p-wave resonances were found, their neutron widths determined, and the PNC longitudinal asymmetries of the resonance cross sections measured. The value obtained for the root-mean-square PNC element M5(0.0620.02 ) meV in Cs is the smallest among all targets studied. This value corresponds to a weak spreading width Gw5(0.00620.003 )31027 eV. @S0556-2813~99!03503-7# PACS number~s!: 24.80.1y, 25.40.Ny, 27.60.1j, 11.30.Er}, number={3}, journal={PHYSICAL REVIEW C}, author={Sharapov, EI and Bowman, JD and Crawford, BE and Delheij, PPJ and Haseyama, T and Knudson, JN and Lowie, LY and Masaike, A and Masuda, Y and Matsuda, Y and et al.}, year={1999}, month={Mar}, pages={1772–1779} }
 @article{lowie_bowman_corvi_crawford_delheij_frankle_iinuma_knudson_masaike_masuda_et al._1999, title={Parity violation in neutron resonances in Ag-107,Ag-109}, volume={59}, DOI={10.1103/physrevc.59.1119}, abstractNote={Parity nonconservation (PNC) was studied in {ital p}-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 {ital p}-wave neutron resonances were studied in {sup 107}Ag and nine {ital p}-wave resonances in {sup 109}Ag. Statistically significant asymmetries were observed for eight resonances in {sup 107}Ag and for four resonances in {sup 109}Ag. An analysis treating the PNC matrix elements as random variables yields a weak spreading width of {Gamma}{sub w}=(2.67{sub {minus}1.21}{sup +2.65}){times}10{sup {minus}7} eV for {sup 107}Ag and {Gamma}{sub w}=(1.30{sub {minus}0.74}{sup +2.49}){times}10{sup {minus}7} eV for {sup 109}Ag. thinsp {copyright} {ital 1999} {ital The American Physical Society}}, number={2}, journal={Physical Review. C, Nuclear Physics}, author={Lowie, L. Y. and Bowman, J. D. and Corvi, F. and Crawford, B. E. and Delheij, P. P. J. and Frankle, C. M. and Iinuma, M. and Knudson, J. N. and Masaike, A. and Masuda, Y. and et al.}, year={1999}, pages={1119–1130} }
 @article{smith_bowman_crawford_grossmann_haseyama_masaike_matsuda_mitchell_penttila_roberson_et al._1999, title={Parity violation in neutron resonances of Rh-103}, volume={60}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.60.045503}, abstractNote={Parity nonconservation (PNC) was studied in p-wave neutron resonances of 103Rh in the neutron energy range 30 to 490 eV. The helicity dependence of the neutron total cross section of rhodium was determined by capture measurements with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at the Los Alamos National Laboratory. A total of 32 p-wave resonances were studied and statistically significant longitudinal asymmetries were observed for resonances at En=44.5, 110.8, 321.6, and 432.9 eV. A statistical analysis treating the PNC matrix elements as random variables yields a weak spreading widthΓw=(1.42-0.59+1.21)×10-7eV. Disciplines Atomic, Molecular and Optical Physics | Physics Authors D A. Smith, J D. Bowman, Bret E. Crawford, C A. Grossmann, T Haseyama, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: https://cupola.gettysburg.edu/physfac/14 Parity violation in neutron resonances of Rh D. A. Smith, J. D. Bowman, 1 B. E. Crawford, 2,* C. A. Grossmann, 3 T. Haseyama, 4 A. Masaike, 4,† Y. Matsuda, 4,‡ G. E. Mitchell, S. I. Penttila, 1 N. R. Roberson, 2 S. J. Seestrom, 1 E. I. Sharapov, 5 S. L. Stephenson, 3,* and V. W. Yuan Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Physics Department, Kyoto University, Kyoto 606-01, Japan Joint Institute for Nuclear Research, Ru-141980 Dubna, Russia ~Received 7 April 1999; published 16 September 1999 ! Parity nonconservation~PNC! was studied inp-wave neutron resonances of Rh in the neutron energy range 30 to 490 eV. The helicity dependence of the neutron total cross section of rhodium was determined by capture measurements with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at the Los Alamos National Laboratory. A total of 32 p-wave resonances were studied and statistically significant longitudinal asymmetries were observed for resonances at En544.5, 110.8, 321.6, and 432.9 eV. A statistical analysis treating the PNC matrix elements as random variables yields a weak spreading width Gw 5(1.4220.59 )31027 eV. @S0556-2813 ~99!06810-7# PACS number ~s!: 25.40.Ny, 11.30.Er, 27.90. 1b}, number={4}, journal={PHYSICAL REVIEW C}, author={Smith, DA and Bowman, JD and Crawford, BE and Grossmann, CA and Haseyama, T and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and Roberson, NR and et al.}, year={1999}, month={Oct} }
 @article{mitchell_bowman_weidenmuller_1999, title={Parity violation in the compound nucleus}, volume={71}, ISSN={["1539-0756"]}, DOI={10.1103/RevModPhys.71.445}, abstractNote={The status of parity violation in the compound nucleus is reviewed. The results of previous experimental results obtained by scattering polarized epithermal neutrons from heavy nuclei in the 3-p and 4-p p-wave strength function peaks are presented. Experimental techniques are presented. The extraction of the mean squared matrix element of the parity-violating interaction, M^2, between compound-nuclear levels and the relationship of M^2 to the coupling strengths in the meson exchange weak nucleon-nucleon potential are discussed. The tendency of measured asymmetries to have a common sign and theoretical implications are discussed. New experimental results are presented that show that the common sign phenomenon is not universal, as theoretical models developed up to now would predict.This talk is dedicated to our friend and colleague Professor Ernest M. Henley, who has done so much to inspire the understanding and study of fundamental symmetries in the nucleus.}, number={1}, journal={REVIEWS OF MODERN PHYSICS}, author={Mitchell, GE and Bowman, JD and Weidenmuller, HA}, year={1999}, month={Jan}, pages={445–457} }
 @article{sharapov_bowman_crawford_delheij_frankle_fukuda_iinuma_knudson_lokitz_lowie_et al._1999, title={Search for parity violation in Nb-93 neutron resonances}, volume={59}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.59.1131}, abstractNote={A new search has been performed for parity violation in the compound nuclear states of ${}^{94}\mathrm{Nb}$ by measuring the helicity dependence of the neutron total cross section. Transmission measurements on a thick niobium target were performed by the time-of-flight method at the Manuel Lujan Neutron Scattering Center with a longitudinally polarized neutron beam in the energy range 32 to 1000 eV. A total of 18 p-wave resonances in ${}^{93}\mathrm{Nb}$ were studied with none exhibiting a statistically significant parity-violating longitudinal asymmetry. An upper limit of $1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ eV (95% confidence level) was obtained for the weak spreading width ${\ensuremath{\Gamma}}_{w}$ in ${}^{93}\mathrm{Nb}.$}, number={2}, journal={PHYSICAL REVIEW C}, author={Sharapov, EI and Bowman, JD and Crawford, BE and Delheij, PPJ and Frankle, CM and Fukuda, K and Iinuma, M and Knudson, JN and Lokitz, SJ and Lowie, LY and et al.}, year={1999}, month={Feb}, pages={1131–1135} }
 @article{berheide_schulte_becker_borucki_buschmann_piel_rolfs_mitchell_schweitzer_1998, title={Average kinetic energy of atoms in a solid measured with resonant nuclear reactions}, volume={58}, ISSN={["1550-235X"]}, DOI={10.1103/physrevb.58.11103}, abstractNote={Solid neon samples at $8\ifmmode\pm\else\textpm\fi{}2$ K and under vapor pressure were used to measure yield curves of the 272-keV nuclear resonance in the ${}^{21}\mathrm{Ne}(p,\ensuremath{\gamma}{)}^{22}\mathrm{Na}$ reaction. The Doppler broadening of the narrow resonance due to target atom motion was determined with very good beam energy resolution. The average kinetic energy of single neon atoms in the solid due to their motion in the beam direction was ${E}_{kin,z}=1.06\ifmmode\pm\else\textpm\fi{}0.2$ meV (corresponding to an average kinetic energy of ${E}_{\mathrm{kin}}/k=37\ifmmode\pm\else\textpm\fi{}7$ K). This value is in good agreement with published values obtained from neutron Compton scattering and from path-integral Monte Carlo calculations.}, number={17}, journal={PHYSICAL REVIEW B}, author={Berheide, M and Schulte, WH and Becker, HW and Borucki, L and Buschmann, M and Piel, N and Rolfs, C and Mitchell, GE and Schweitzer, JS}, year={1998}, month={Nov}, pages={11103–11106} }
 @article{crawford_bowman_delheij_haseyama_knudson_lowie_masaike_matsuda_mitchell_penttila_et al._1998, title={Neutron resonance spectroscopy of Pd-106 and Pd-108 from 20 to 2000 eV}, volume={58}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.58.729}, abstractNote={Parity nonconserving asymmetries have been measured in p-wave resonances of 106Pd and 108Pd. The data analysis requires knowledge of the neutron resonance parameters. Transmission and capture γ-ray yields were measured for En=20–2000 eV with the time-of-flight method at the Los Alamos Neutron Science Center (LANSCE). A total of 28 resonances in 106Pd and 32 resonances in 108Pd were studied. The resonance parameters for 106Pd are new for all except one resonance. In 108Pd six new resonances were observed and the precision improved for many of the resonance parameters. A Bayesian analysis was used to assign orbital angular momentum for the resonances studied. Disciplines Atomic, Molecular and Optical Physics | Physics Authors Bret E. Crawford, J D. Bowman, P P J. Delheij, T Haseyama, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/23 Neutron resonance spectroscopy of Pd and Pd from 20 to 2000 eV B. E. Crawford,* J. D. Bowman, P. P. J. Delheij, T. Haseyama, J. N. Knudson, L. Y. Lowie, A. Masaike, Y. Matsuda, G. E. Mitchell, S. I. Penttila, H. Postma, N. R. Roberson, S. J. Seestrom, E. I. Sharapov, S. L. Stephenson, and V. W. Yuan Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Los Alamos National Laboratory, Los Alamos, New Mexico 87545 TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 Physics Department, Kyoto University, Kyoto 606-01, Japan North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 University of Technology, Delft, 2600 GA, The Netherlands Joint Institute for Nuclear Research, 141980 Dubna, Russia ~Received 23 January 1998! Parity nonconserving asymmetries have been measured in p-wave resonances of Pd and Pd. The data analysis requires knowledge of the neutron resonance parameters. Transmission and capture g-ray yields were measured for En520–2000 eV with the time-of-flight method at the Los Alamos Neutron Science Center ~LANSCE!. A total of 28 resonances in Pd and 32 resonances in Pd were studied. The resonance parameters for Pd are new for all except one resonance. In Pd six new resonances were observed and the precision improved for many of the resonance parameters. A Bayesian analysis was used to assign orbital angular momentum for the resonances studied. @S0556-2813~98!01208-4# PACS number~s!: 24.30.2v, 25.40.Ny, 27.60.1j, 24.80.1y}, number={2}, journal={PHYSICAL REVIEW C}, author={Crawford, BE and Bowman, JD and Delheij, PPJ and Haseyama, T and Knudson, JN and Lowie, LY and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and et al.}, year={1998}, month={Aug}, pages={729–738} }
 @article{seestrom_bowman_crawford_delheij_frankle_gould_haase_linuma_knudson_koehler_et al._1998, title={Parity nonconservation in neutron capture on Cd-113}, volume={58}, number={5}, journal={Physical Review. C, Nuclear Physics}, author={Seestrom, S. J. and Bowman, J. D. and Crawford, B. E. and Delheij, P. P. J. and Frankle, C. M. and Gould, C. R. and Haase, D. G. and Linuma, M. and Knudson, J. N. and Koehler, P. E. and et al.}, year={1998}, pages={2977–2985} }
 @article{stephenson_bowman_crawford_delheij_frankle_iinuma_knudson_lowie_masaike_matsuda_et al._1998, title={Parity nonconservation in neutron resonances in Th-232}, volume={58}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.58.1236}, abstractNote={Parity nonconservation (PNC) was measured for 24 p-wave resonances from 8 to 300 eV in 232Th by measuring the helicity dependence of the total neutron cross section for epithermal neutrons with an improved experimental system. Ten resonances show statistically significant parity violation. For these ten resonances the analyzing powers are all positive, thus confirming the previously observed sign correlation. The data are fit to the sum of two terms, a constant asymmetry and a fluctuating asymmetry. With this ansatz the root-mean-square PNC matrix element M=1.12 meV, which corresponds to a weak spreading widthΓw=4.7×10-7 eV. For the neighboring nuclide 238U there is no constant offset, suggesting that the sign correlation is specific to 232Th. Disciplines Atomic, Molecular and Optical Physics | Physics Authors Sharon L. Stephenson, J D. Bowman, Bret E. Crawford, P P J. Delheij, C M. Frankle, M IInuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, Y-F Yen, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/20 Parity nonconservation in neutron resonances in Th S. L. Stephenson,* J. D. Bowman, B. E. Crawford, P. P. J. Delheij, C. M. Frankle, M. Iinuma, J. N. Knudson, L. Y. Lowie, A. Masaike, Y. Matsuda, G. E. Mitchell, S. I. Penttila, H. Postma, N. R. Roberson, S. J. Seestrom, E. I. Sharapov, Y.-F. Yen, and V. W. Yuan North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 Department of Physics, Kyoto University, Kyoto 606-8502, Japan University of Technology, Delft, 2600 GA, The Netherlands Joint Institute for Nuclear Research, 141980 Dubna, Russia ~Received 6 April 1998! Parity nonconservation ~PNC! was measured for 24 p-wave resonances from 8 to 300 eV in Th by measuring the helicity dependence of the total neutron cross section for epithermal neutrons with an improved experimental system. Ten resonances show statistically significant parity violation. For these ten resonances the analyzing powers are all positive, thus confirming the previously observed sign correlation. The data are fit to the sum of two terms, a constant asymmetry and a fluctuating asymmetry. With this ansatz the root-meansquare PNC matrix element M51.12 meV, which corresponds to a weak spreading width Gw54.7310 27 eV. For the neighboring nuclide U there is no constant offset, suggesting that the sign correlation is specific to Th. @S0556-2813~98!03608-5# PACS number~s!: 25.40.Ny, 24.80.1y, 11.30.Er, 27.90.1b}, number={2}, journal={PHYSICAL REVIEW C}, author={Stephenson, SL and Bowman, JD and Crawford, BE and Delheij, PPJ and Frankle, CM and Iinuma, M and Knudson, JN and Lowie, LY and Masaike, A and Matsuda, Y and et al.}, year={1998}, month={Aug}, pages={1236–1246} }
 @article{crawford_bowman_delheij_frankle_iinuma_knudson_lowie_masaike_matsuda_mitchell_et al._1998, title={Parity nonconservation in neutron resonances in U-238}, volume={58}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.58.1225}, abstractNote={Parity nonconservation (PNC) was studied for 24 p-wave neutron resonances in 238U from 10 to 300 eV by measuring the helicity dependence of the total neutron cross section with an improved experimental apparatus. Six resonances show statistically significant (greater than 2.9σ) parity violation. An analysis treating the PNC matrix elements as random variables yields a root-mean-square PNC matrix element M=0.67-0.16+0.24 meV. The corresponding weak spreading width Γw=(1.35-0.64+0.97)×10-7 eV. Disciplines Atomic, Molecular and Optical Physics | Physics Authors Bret E. Crawford, J D. Bowman, P P J. Delheij, C M. Frankle, M IInuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, Y-F Yen, and V W. Yuan This article is available at The Cupola: Scholarship at Gettysburg College: http://cupola.gettysburg.edu/physfac/22 Parity nonconservation in neutron resonances in U B. E. Crawford,* J. D. Bowman, P. P. J. Delheij, C. M. Frankle, M. Iinuma, J. N. Knudson, L. Y. Lowie, A. Masaike, Y. Matsuda, G. E. Mitchell, S. I. Penttila, H. Postma, N. R. Roberson, S. J. Seestrom, E. I. Sharapov, S. L. Stephenson, Y.-F. Yen, and V. W. Yuan ~TRIPLE Collaboration! Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 Los Alamos National Laboratory, Los Alamos, New Mexico 87545 TRIUMF, Vancouver, British Columbia, Canada V6T 2A3 Department of Physics, Kyoto University, Kyoto 606-8502, Japan North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 University of Technology, Delft, 2600 GA, the Netherlands Joint Institute for Nuclear Research, 141980 Dubna, Russia ~Received 6 April 1998! Parity nonconservation ~PNC! was studied for 24 p-wave neutron resonances in U from 10 to 300 eV by measuring the helicity dependence of the total neutron cross section with an improved experimental apparatus. Six resonances show statistically significant ~greater than 2.9s) parity violation. An analysis treating the PNC matrix elements as random variables yields a root-mean-square PNC matrix element M50.6720.16 10.24 meV. The corresponding weak spreading width Gw5(1.3520.64 )31027 eV. @S0556-2813~98!03708-X# PACS number~s!: 25.40.Ny, 24.80.1y, 11.30.Er, 27.90.1b}, number={2}, journal={PHYSICAL REVIEW C}, author={Crawford, BE and Bowman, JD and Delheij, PPJ and Frankle, CM and Iinuma, M and Knudson, JN and Lowie, LY and Masaike, A and Matsuda, Y and Mitchell, GE and et al.}, year={1998}, month={Aug}, pages={1225–1235} }
 @article{adams_mitchell_shriner_1998, title={Statistical distribution of reduced transition probabilities in Al-26}, volume={422}, ISSN={["0370-2693"]}, DOI={10.1016/S0370-2693(98)00031-8}, abstractNote={Reduced electromagnetic transition matrix elements were determined for levels in 26 Al from the ground state to 8 MeV. In this energy region in 26 Al, states with isospin 0 and 1 coexist, and isospin is approximately 97% conserved. These data provide the first test of the effect of symmetry breaking on the transition matrix element distribution. The experimental distribution deviates significantly from the Porter-Thomas distribution.}, number={1-4}, journal={PHYSICS LETTERS B}, author={Adams, AA and Mitchell, GE and Shriner, JF}, year={1998}, month={Mar}, pages={13–18} }
 @article{yen_bowman_lowie_masuda_mitchell_penttila_1997, title={Determination of the gamma-ray background in a pulsed epithermal neutron beam}, volume={397}, ISSN={["0168-9002"]}, DOI={10.1016/s0168-9002(97)00709-2}, abstractNote={The γ-ray background in the pulsed neutron beam at the Los Alamos Neutron Scattering Center was measured with an array of 10B-loaded liquid scintillators. With the method employed the γ-ray contribution in the neutron beam can be determined without knowledge of the energy spectrum of the γ-rays. The ratio of γ-ray to neutron intensities in the beam was determined during the time interval following the beam burst that corresponds to neutron energies from En = 1 to 340 eV. The γ-ray content in the beam ranges from 2% at 1 eV to 10% at 340 eV.}, number={2-3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Yen, YF and Bowman, JD and Lowie, LY and Masuda, Y and Mitchell, GE and Penttila, SI}, year={1997}, month={Oct}, pages={365–370} }
 @article{adams_mitchell_ormand_shriner_1997, title={Distribution of shell model reduced transition probabilities in Na-22}, volume={392}, ISSN={["0370-2693"]}, DOI={10.1016/S0370-2693(96)01510-9}, abstractNote={The distribution of reduced transition probabilities in 22Na has been studied using the shell model. B(M1) and B(E2) values have been calculated for transitions among the first 25 states with each spin from J = 0 to J = 8, positive parity, and isospins T = 0 or T = 1. No dependence on spin, isospin, electromagnetic character, or excitation energy was found. The results were consistent with a χ2(ν) distribution with ν = 1, suggesting that 22Na is chaotic in the energy range studied.}, number={1-2}, journal={PHYSICS LETTERS B}, author={Adams, AA and Mitchell, GE and Ormand, WE and Shriner, JF}, year={1997}, month={Jan}, pages={1–6} }
 @article{lowie_bowman_crawford_delheij_haseyama_knudson_masaike_matsuda_mitchell_penttila_et al._1997, title={Neutron resonance spectroscopy of Ag-107 and Ag-109}, volume={56}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.56.90}, abstractNote={Parity violation has been observed in a number of previously unreported neutron resonances in silver. Analysis of these parity violation data requires improved neutron resonance spectroscopy. The neutron total cross section for natural silver was measured for E{sub n}=10{endash}800 eV with the time-of-flight method at the Los Alamos Neutron Scattering Center. The neutron capture reaction was studied with both a natural silver target and a highly enriched sample (98.29{percent}) of {sup 107}Ag. A total of 38 previously unreported resonances were observed. The combination of the two measurements allowed assignment of the newly observed resonances to {sup 107}Ag or to {sup 109}Ag. Resonance parameters were determined for almost all of the neutron resonances observed. {copyright} {ital 1997} {ital The American Physical Society}}, number={1}, journal={PHYSICAL REVIEW C}, author={Lowie, LY and Bowman, JD and Crawford, BE and Delheij, PPJ and Haseyama, T and Knudson, JN and Masaike, A and Matsuda, Y and Mitchell, GE and Penttila, SI and et al.}, year={1997}, month={Jul}, pages={90–97} }
 @article{rightor_hitchcock_ade_leapman_urquhart_smith_mitchell_fischer_shin_warwick_1997, title={Spectromicroscopy of poly(ethylene terephthalate): Comparison of spectra and radiation damage rates in x-ray absorption and electron energy loss}, volume={101}, ISSN={["1520-5207"]}, DOI={10.1021/jp9622748}, abstractNote={The C 1s and O 1s X-ray absorption spectra of poly(ethylene terephthalate) (PET) have been recorded using transmission, fluorescence, and electron yield detection. The corresponding electron energy loss spectra (EELS) have been recorded in a scanning transmission electron microscope. These results are compared to the C 1s and O 1s spectra of gas phase 1,4-dimethyl terephthalate (the monomer of PET) recorded using EELS. The comparison of monomer and polymer materials in different phases and with different techniques has aided the understanding of the relative strengths and limitations of each technique as well as assisting the spectral interpretation. Good agreement is found in the overall shape and the energies of the spectral features. Relatively minor differences in intensities can be understood in terms of the properties of the individual spectroscopic techniques. The critical dose for radiation damage by 100 keV electrons incident on PET at 100 K is found to be (1.45 ± 0.15) × 103 eV nm-3. In contrast...}, number={11}, journal={JOURNAL OF PHYSICAL CHEMISTRY B}, author={Rightor, EG and Hitchcock, AP and Ade, H and Leapman, RD and Urquhart, SG and Smith, AP and Mitchell, G and Fischer, D and Shin, HJ and Warwick, T}, year={1997}, month={Mar}, pages={1950–1960} }
 @article{vavrina_bilpuch_bybee_mitchell_moore_shriner_shriner_wallace_westerfeldt_1997, title={Spectroscopy of the Si-29(p,gamma) reaction for E(p)=1.00-1.75 MeV}, volume={55}, ISSN={["1089-490X"]}, DOI={10.1103/physrevc.55.1119}, abstractNote={The ${}^{29}$Si$(p,\ensuremath{\gamma})$ reaction has been studied in the range ${E}_{p}=1.00$--1.75 MeV. Three previously unknown states in ${}^{30}$P were identified, and one state previously assigned to ${}^{30}$P was identified as a state in ${}^{14}$N. Gamma-ray strengths were determined for the three new levels, and branching ratios were measured for 17 resonances. Revised ${J}^{\ensuremath{\pi}};T$ assignments were made for nine of these states.}, number={3}, journal={PHYSICAL REVIEW C}, author={Vavrina, GA and Bilpuch, EG and Bybee, CR and Mitchell, GE and Moore, EF and Shriner, JD and Shriner, JF and Wallace, PM and Westerfeldt, CR}, year={1997}, month={Mar}, pages={1119–1125} }