@article{sun_adamek_allgeier_bagdasarova_berguno_blatnik_bowles_broussard_brown_carr_et al._2020, title={Improved limits on Fierz interference using asymmetry measurements from the Ultracold Neutron Asymmetry (UCNA) experiment}, volume={101}, ISSN={2469-9985 2469-9993}, url={http://dx.doi.org/10.1103/PhysRevC.101.035503}, DOI={10.1103/PhysRevC.101.035503}, abstractNote={The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the β-decay asymmetry parameter, A₀, for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their β-decay electrons are detected with ≈4π acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to b_n, the Fierz interference term in the neutron β-decay rate. In this work, we determine b_n from the energy dependence of A₀ using the data taken during the UCNA 2011-2013 run. In addition, we present the same type of analysis using the earlier 2010 A dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new b_n measurement using the weighted average of our asymmetry dataset fits, to obtain b_n = 0.066±0.041_(stat)±0.024_(syst) which corresponds to a limit of −0.012 < b_n < 0.144 at the 90% confidence level.}, number={3}, journal={Physical Review C}, publisher={American Physical Society (APS)}, author={Sun, X. and Adamek, E. and Allgeier, B. and Bagdasarova, Y. and Berguno, D. B. and Blatnik, M. and Bowles, T. J. and Broussard, L. J. and Brown, M. A.-P. and Carr, R. and et al.}, year={2020}, month={Mar} }
 @article{broussard_zeck_adamek_baeßler_birge_blatnik_bowman_brandt_brown_burkhart_et al._2017, title={Detection system for neutron beta decay correlations in the UCNB and Nab experiments}, volume={849}, ISSN={0168-9002}, url={http://dx.doi.org/10.1016/J.NIMA.2016.12.030}, DOI={10.1016/j.nima.2016.12.030}, abstractNote={We describe a detection system designed for precise measurements of angular correlations in neutron $\beta$ decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for $\beta$ electron detection with energy thresholds below 10 keV, energy resolution of $\sim$3 keV FWHM, and rise time of $\sim$50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of $\beta$ particles and recoil protons from neutron $\beta$ decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments, to determine the neutron $\beta$ decay parameters $B$, $a$, and $b$.}, journal={Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors, and Associated Equipment}, publisher={Elsevier BV}, author={Broussard, L.J. and Zeck, B.A. and Adamek, E.R. and Baeßler, S. and Birge, N. and Blatnik, M. and Bowman, J.D. and Brandt, A.E. and Brown, M. and Burkhart, J. and et al.}, year={2017}, pages={83–93} }
 @article{hickerson_sun_bagdasarova_bravo-berguno_broussard_brown_carr_currie_ding_filippone_et al._2017, title={First direct constraints on Fierz interference in free-neutron beta decay}, volume={96}, number={4}, journal={Physical Review C}, author={Hickerson, K. P. and Sun, X. and Bagdasarova, Y. and Bravo-Berguno, D. and Broussard, L. J. and Brown, M. A. P. and Carr, R. and Currie, S. and Ding, X. and Filippone, B. W. and et al.}, year={2017} }
 @article{seestrom_adamek_barlow_broussard_callahan_clayton_cude-woods_currie_dees_fox_et al._2015, title={Upscattering of ultracold neutrons from gases}, volume={92}, ISSN={1089-490X}, DOI={10.1103/physrevc.92.065501}, abstractNote={We present measurements of the upscattering cross sections of ultracold neutrons (UCNs) from room-temperature hydrogen, deuterium, neon, argon, xenon, ${\mathrm{C}}_{4}{\mathrm{H}}_{10}, \mathrm{C}{\mathrm{F}}_{4}$, and air. The values of these cross sections are important for estimating the loss rate of trapped neutrons due to residual gas and are therefore of importance for neutron lifetime measurements using UCNs. Cross sections were obtained from a combined analysis of the UCN attenuation in a gas cell and direct measurement of the neutrons upscattered in the cell. The effects of the UCN velocity and path-length distributions were accounted for using a Monte Carlo transport code. Results are compared with measurements at higher neutron energy as well as with calculations.}, number={6}, journal={PHYSICAL REVIEW C}, author={Seestrom, S. J. and Adamek, E. R. and Barlow, D. and Broussard, L. J. and Callahan, N. B. and Clayton, S. M. and Cude-Woods, C. and Currie, S. and Dees, E. B. and Fox, W. and et al.}, year={2015}, month={Dec} }
 @article{salvat_adamek_barlow_bowman_broussard_callahan_clayton_cude-woods_currie_dees_et al._2014, title={Storage of ultracold neutrons in the magneto-gravitational trap of the UCN tau experiment}, volume={89}, ISSN={1089-490X}, DOI={10.1103/physrevc.89.052501}, abstractNote={The UCN experiment is designed to measure the lifetime n of the free neutron by trapping ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach array confines low-field-seeking UCN within the apparatus, and a set of electromagnetic coils in a toroidal geometry provides a background holding field to eliminate depolarization-induced UCN loss caused by magnetic field nodes. We present a measurement of the storage time store of the trap by storing UCN for various times and counting the survivors. The data are consistent with a single exponential decay, and we find store = 860 19 s, within 1 of current global averages for n. The storage time with the holding field deactivated is found to be store = 470 160 s; this decreased storage time is due to the loss of UCN, which undergo Majorana spin flips while being stored. We discuss plans to increase the statistical sensitivity of the measurement and investigate potential systematic effects.}, number={5}, journal={PHYSICAL REVIEW C}, author={Salvat, D. J. and Adamek, E. R. and Barlow, D. and Bowman, J. D. and Broussard, L. J. and Callahan, N. B. and Clayton, S. M. and Cude-Woods, C. and Currie, S. and Dees, E. B. and et al.}, year={2014}, month={May} }
 @article{sharapov_morris_makela_saunders_adamek_bagdasarova_broussard_cude-woods_fellers_geltenbort_et al._2013, title={Measurements of ultracold neutron upscattering and absorption in polyethylene and vanadium}, volume={88}, ISSN={1089-490X}, DOI={10.1103/physrevc.88.037601}, abstractNote={The study of neutron cross sections for elements used as efficient “absorbers” of ultracold neutrons (UCN) is crucial for many precision experiments in nuclear and particle physics, cosmology and gravity. In this context, “absorption” includes both the capture and upscattering of neutrons to the energies above the UCN energy region. The available data, especially for hydrogen, do not agree between themselves or with the theory. In this report we describe measurements performed at the Los Alamos National Laboratory UCN facility of the UCN upscattering cross sections for vanadium and for hydrogen in CH_2 using simultaneous measurements of the radiative capture cross sections for these elements. We measured σ_(up)=1972±130 b for hydrogen in CH_2, which is below theoretical expectations, and σ_(up)=25±9 b for vanadium, in agreement with the expectation for the neutron heating by thermal excitations in solids.}, number={3}, journal={PHYSICAL REVIEW C}, author={Sharapov, E. I. and Morris, C. L. and Makela, M. and Saunders, A. and Adamek, Evan R. and Bagdasarova, Y. and Broussard, L. J. and Cude-Woods, C. B. and Fellers, Deion E. and Geltenbort, Peter and et al.}, year={2013}, month={Sep} }
 @article{saunders_makela_bagdasarova_back_boissevain_broussard_bowles_carr_currie_filippone_et al._2013, title={Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source}, volume={84}, ISSN={0034-6748 1089-7623}, url={http://dx.doi.org/10.1063/1.4770063}, DOI={10.1063/1.4770063}, abstractNote={In this paper, we describe the performance of the Los Alamos spallation-driven solid-deuterium ultra-cold neutron (UCN) source. Measurements of the cold neutron flux, the very low energy neutron production rate, and the UCN rates and density at the exit from the biological shield are presented and compared to Monte Carlo predictions. The cold neutron rates compare well with predictions from the Monte Carlo code MCNPX and the UCN rates agree with our custom UCN Monte Carlo code. The source is shown to perform as modeled. The maximum delivered UCN density at the exit from the biological shield is 52(9) UCN/cc with a solid deuterium volume of ∼1500 cm3.}, number={1}, journal={Review of Scientific Instruments}, publisher={AIP Publishing}, author={Saunders, A. and Makela, M. and Bagdasarova, Y. and Back, H. O. and Boissevain, J. and Broussard, L. J. and Bowles, T. J. and Carr, R. and Currie, S. A. and Filippone, B. and et al.}, year={2013}, pages={013304} }
 @article{salvat_morris_wang_adamek_bacon_nickerson_hoagland_holley_liu_makela_et al._2012, title={A boron-coated ionization chamber for ultra-cold neutron detection}, volume={691}, ISSN={1872-9576}, DOI={10.1016/j.nima.2012.06.041}, abstractNote={The design and performance of a boron-coated ionization chamber for the detection of ultra-cold neutrons (UCN) are presented. We detect UCN from the solid deuterium-based UCN source at the Los Alamos Neutron Science Center. Our results indicate comparable efficiency to 3He ionization chambers and proportional counters currently used at the UCN source. In addition, the ion chamber is used to detect thermal neutrons; a comparison of the thermal neutron and UCN pulse-height spectra indicates that UCN mostly capture near the layer surface.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Salvat, D. J. and Morris, C. L. and Wang, Z. and Adamek, E. R. and Bacon, J. and Nickerson, K. P. and Hoagland, J. and Holley, A. T. and Liu, C-Y and Makela, M. and et al.}, year={2012}, month={Nov}, pages={109–112} }
 @article{plaster_rios_back_bowles_broussard_carr_clayton_currie_filippone_garcia_et al._2012, title={Measurement of the neutron beta-asymmetry parameter A(0) with ultracold neutrons}, volume={86}, number={5}, journal={Physical Review. C, Nuclear Physics}, author={Plaster, B. and Rios, R. and Back, H. O. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clayton, S. and Currie, S. and Filippone, B. W. and Garcia, A. and et al.}, year={2012} }
 @article{liu_mendenhall_holley_back_bowles_broussard_carr_clayton_currie_filippone_et al._2010, title={Determination of the axial-vector weak coupling constant with ultracold neutrons}, volume={105}, number={18}, journal={Physical Review Letters}, author={Liu, J. and Mendenhall, M. P. and Holley, A. T. and Back, H. O. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clayton, S. and Currie, S. and Filippone, B. W. and et al.}, year={2010} }