@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{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{schiller_voinov_algin_becker_bernstein_garrett_guttormsen_nelson_rekstad_siem_2006, title={Low-energy M1 excitation mode in Yb-172}, volume={633}, DOI={10.1016/j.physletb.2005.12.043}, abstractNote={The multipolarity of a soft (Eγ=3.3(1)MeV) resonance in the total radiative strength function (RSF) of 172Yb is determined. For this reason, the level density and total RSF of 172Yb have been extracted from primary-γ spectra from the 173Yb(3He, αγ)172Yb reaction. In a second experiment, two-step-cascade (TSC) intensities have been measured in the 171Yb(nth,γγ)172Yb reaction. These intensities are compared to statistical-model calculations which are entirely based on experimental values of the level density and RSF from the former experiment. This comparison implies M1 assignment of the soft resonance. The strength of the M1 resonance is B(M1↑)=6.5(15)μN2.}, number={2-3}, journal={Physics Letters. B}, author={Schiller, A. and Voinov, A. V. and Algin, E. and Becker, J. A. and Bernstein, L. A. and Garrett, P. E. and Guttormsen, M. and Nelson, R. O. and Rekstad, J. and Siem, S.}, year={2006}, pages={225–230} }
 @article{schiller_voinov_algin_bernstein_garrett_guttormsen_nelson_rekstad_siem_2006, title={Primary versus secondary gamma intensities in Yb-171(n(th), gamma)}, volume={74}, number={1}, journal={Physical Review. C, Nuclear Physics}, author={Schiller, A. and Voinov, A. V. and Algin, E. and Bernstein, L. A. and Garrett, P. E. and Guttormsen, M. and Nelson, R. O. and Rekstad, J. and Siem, S.}, year={2006} }
 @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} }