@article{gonzalez_fries_cude-woods_bailey_blatnik_broussard_callahan_choi_clayton_currie_et al._2021, title={Improved Neutron Lifetime Measurement with UCN τ}, volume={127}, ISSN={["1079-7114"]}, DOI={10.1103/PhysRevLett.127.162501}, abstractNote={We report an improved measurement of the free neutron lifetime τ_{n} using the UCNτ apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38×10^{6} surviving ultracold neutrons (UCNs) after storing in UCNτ's magnetogravitational trap over two data acquisition campaigns in 2017 and 2018. We extract τ_{n} from three blinded, independent analyses by both pairing long and short storage time runs to find a set of replicate τ_{n} measurements and by performing a global likelihood fit to all data while self-consistently incorporating the β-decay lifetime. Both techniques achieve consistent results and find a value τ_{n}=877.75±0.28_{stat}+0.22/-0.16_{syst}  s. With this sensitivity, neutron lifetime experiments now directly address the impact of recent refinements in our understanding of the standard model for neutron decay.}, number={16}, journal={PHYSICAL REVIEW LETTERS}, author={Gonzalez, F. M. and Fries, E. M. and Cude-Woods, C. and Bailey, T. and Blatnik, M. and Broussard, L. J. and Callahan, N. B. and Choi, J. H. and Clayton, S. M. and Currie, S. A. and et al.}, year={2021}, month={Oct}, pages={162501} }
 @article{kuk_cude-woods_chavez_choi_estrada_hoffbauer_holland_makela_morris_ramberg_et al._2021, title={Projection imaging with ultracold neutrons}, volume={1003}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2021.165306}, abstractNote={Ultracold neutron (UCN) projection imaging is demonstrated using a boron-coated back-illuminated CCD camera and the Los Alamos UCN source. Each neutron is recorded through the capture reactions with 10B. By direct detection at least one of the byproducts α, 7Li and γ (electron recoils) derived from the neutron capture and reduction of thermal noise of the scientific CCD camera, a signal-to-noise improvement on the order of 104 over the indirect detection has been achieved. Sub-pixel position resolution of a few microns is confirmed for individual UCN events. Projection imaging of test objects shows a spatial resolution less than 100μm by an integrated UCN flux one the order of 106 cm−2. The bCCD can be used to build UCN detectors with an area on the order of 1 m2. The combination of micrometer scale spatial resolution, low readout noise of a few electrons, and large area makes bCCD suitable for quantum science of UCN.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Kuk, K. and Cude-Woods, C. and Chavez, C. R. and Choi, J. H. and Estrada, J. and Hoffbauer, M. and Holland, S. E. and Makela, M. and Morris, C. L. and Ramberg, E. and et al.}, year={2021}, month={Jul} }
 @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{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{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{holley_broussard_davis_hickerson_ito_liu_lyles_makela_mammei_mendenhall_et al._2012, title={A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment}, volume={83}, ISSN={0034-6748 1089-7623}, url={http://dx.doi.org/10.1063/1.4732822}, DOI={10.1063/1.4732822}, abstractNote={The UCNA collaboration is making a precision measurement of the β asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be \documentclass[12pt]{minimal}\begin{document}$\overline{\epsilon }=0.9985(4)$\end{document}ε¯=0.9985(4).}, number={7}, journal={Review of Scientific Instruments}, publisher={AIP Publishing}, author={Holley, A. T. and Broussard, L. J. and Davis, J. L. and Hickerson, K. and Ito, T. M. and Liu, C. Y. and Lyles, J. T. M. and Makela, M. and Mammei, R. R. and Mendenhall, M. P. and et al.}, year={2012}, pages={073505} }
 @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{atchison_blau_bodek_brandt_brys_daum_fierlinger_geltenbort_hautle_henneck_et al._2011, title={Production of ultracold neutrons from cryogenic H-2(2), O-2, and (CH4)-H-2 converters}, volume={95}, number={1}, journal={Europhysics Letters}, author={Atchison, F. and Blau, B. and Bodek, K. and Brandt, B. and Brys, T. and Daum, M. and Fierlinger, P. and Geltenbort, P. and Hautle, P. and Henneck, R. and et al.}, year={2011} }
 @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} }
 @article{rios_tatar_bacon_bowles_hill_green_hogan_ito_makela_morris_et al._2011, title={Sealed drift tube cosmic ray veto counters}, volume={637}, ISSN={0168-9002}, url={http://dx.doi.org/10.1016/J.NIMA.2010.12.098}, DOI={10.1016/j.nima.2010.12.098}, abstractNote={We describe a simple drift tube counter that has been used as a cosmic ray veto for the UCNA experiment, a first-ever measurement of the neutron beta-asymmetry using ultra-cold neutrons. These detectors provide an inexpensive alternative to more conventional scintillation detectors for large area cosmic ray anticoincidence detectors.}, number={1}, journal={Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors, and Associated Equipment}, publisher={Elsevier BV}, author={Rios, R. and Tatar, E. and Bacon, J.D. and Bowles, T.J. and Hill, R. and Green, J.A. and Hogan, G.E. and Ito, T.M. and Makela, M. and Morris, C.L. and et al.}, year={2011}, pages={105–108} }
 @article{sallaska_hoedl_garcia_melconian_young_geltenbort_sjue_holley_2009, title={Characterization of thin-foil ultracold neutron detectors}, volume={603}, ISSN={0168-9002}, DOI={10.1016/j.nima.2009.02.014}, abstractNote={We have fabricated ultracold neutron detectors that consist of silicon charged particle detectors coupled with thin nickel foils coated with either natural LiF or 10 B implanted into vanadium. The foils convert neutrons into energetic, readily detectable, charged particles which are in turn detected by silicon detectors. The detectors were tested at the Institut Laue-Langevin with a gravitational spectrometer. From a rigorous Monte Carlo simulation of the experiment, the minimum detection cutoff velocities (effective potentials) were determined to be 309 � 17 cm=s (49:8 � 2:7 neV) for LiF and 367 � 39 cm=s (70:3 � 7:5 neV) for 10 B/V. Although the result for LiF is consistent with expectations, the result for 10 B/V is significantly higher. We interpret this discrepancy as due to contamination. We also show that while a thicker foil is more efficient for ultracold neutron detection, a thinner foil is more ideal for determining the cutoff velocity. Published by Elsevier B.V.}, number={3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Sallaska, A. L. and Hoedl, S. and Garcia, A. and Melconian, D. and Young, A. R. and Geltenbort, P. and Sjue, S. K. L. and Holley, A. T.}, year={2009}, month={May}, pages={421–428} }
 @article{pattie_anaya_back_boissevain_bowles_broussard_carr_clark_currie_du_et al._2009, title={First measurement of the neutron beta asymmetry with ultracold neutrons}, volume={102}, number={1}, journal={Physical Review Letters}, author={Pattie, R. W. and Anaya, J. and Back, H. O. and Boissevain, J. G. and Bowles, T. J. and Broussard, L. J. and Carr, R. and Clark, D. J. and Currie, S. and Du, S. and et al.}, year={2009} }
 @article{morris_bowles_gonzales_hill_hogan_makela_mortenson_ramsey_saunders_seestrom_et al._2009, title={Multi-wire proportional chamber for ultra-cold neutron detection}, volume={599}, ISSN={0168-9002}, DOI={10.1016/j.nima.2008.11.099}, abstractNote={In this paper we describe the principles that have guided our design and the experience we have gained building multi-wire proportional chambers detectors for the ultra-cold neutron (UCN) source at the Los Alamos Neutron Science Center (LANSCE). Simple robust detectors with 50 cm2 of active area have been designed. These have been used both in ion chamber and proportional mode for the detection of UCN.}, number={2-3}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Morris, C. L. and Bowles, T. J. and Gonzales, J. and Hill, R. and Hogan, G. and Makela, M. and Mortenson, R. and Ramsey, J. and Saunders, A. and Seestrom, S. J. and et al.}, year={2009}, month={Feb}, pages={248–250} }
 @article{atchison_blau_bodek_brandt_brys_daum_fierlinger_frei_geltenbort_hautle_et al._2007, title={Cold neutron energy dependent production of ultracold neutrons in solid deuterium}, volume={99}, number={26}, journal={Physical Review Letters}, author={Atchison, F. and Blau, B. and Bodek, K. and Brandt, B. and Brys, T. and Daum, M. and Fierlinger, P. and Frei, A. and Geltenbort, P. and Hautle, P. and et al.}, year={2007} }