@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{morris_adamek_broussard_callahan_clayton_cude-woods_currie_ding_fox_hickerson_et al._2017, title={A new method for measuring the neutron lifetime using an in situ neutron detector}, volume={88}, ISSN={1089-7623}, url={http://dx.doi.org/10.1063/1.4983578}, DOI={10.1063/1.4983578}, abstractNote={In this paper, we describe a new method for measuring surviving neutrons in neutron lifetime measurements using bottled ultracold neutrons (UCN), which provides better characterization of systematic uncertainties and enables higher precision than previous measurement techniques. An active detector that can be lowered into the trap has been used to measure the neutron distribution as a function of height and measure the influence of marginally trapped UCN on the neutron lifetime measurement. In addition, measurements have demonstrated phase-space evolution and its effect on the lifetime measurement.}, number={5}, journal={REVIEW OF SCIENTIFIC INSTRUMENTS}, publisher={AIP Publishing}, author={Morris, C. L. and Adamek, E. R. and Broussard, L. J. and Callahan, N. B. and Clayton, S. M. and Cude-Woods, C. and Currie, S. A. and Ding, X. and Fox, W. and Hickerson, K. P. and et al.}, year={2017}, month={May}, pages={053508} }
 @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{broussard_alarcon_baessler_barron palos_birge_bode_bowman_brunst_calarco_caylor_et al._2017, title={Neutron decay correlations in the Nab experiment}, volume={876}, ISSN={1742-6596}, DOI={10.1088/1742-6596/876/1/012005}, abstractNote={The Nab experiment will measure the correlation a between the momenta of the beta particle and antineutrino in neutron decay as well as the Fierz term b which distorts the beta spectrum.}, journal={XL SYMPOSIUM ON NUCLEAR PHYSICS 2017 (COCOYOC2017)}, author={Broussard, L. J. and Alarcon, R. and Baessler, S. and Barron Palos, L. and Birge, N. and Bode, T. and Bowman, J. D. and Brunst, T. and Calarco, J. R. and Caylor, J. and et al.}, year={2017} }
 @article{seestrom_adamek_barlow_blatnik_broussard_callahan_clayton_cude-woods_currie_dees_et al._2017, title={Total cross sections for ultracold neutrons scattered from gases}, volume={95}, ISSN={2469-9993}, DOI={10.1103/physrevc.95.015501}, abstractNote={We have followed up on our previous measurements of upscattering of ultracold neutrons (UCNs) from a series of gases by making measurements of total cross sections on the following gases hydrogen, ethane, methane, isobutene, n-butane, ethylene, water vapor, propane, neopentane, isopropyl alcohol, and ^3He. The values of these cross sections are important for estimating the loss rate of trapped neutrons due to residual gas and are relevant to neutron lifetime measurements using UCNs. The effects of the UCN velocity and path-length distributions were accounted for in the analysis using a Monte Carlo transport code. Results are compared to our previous measurements and with the known absorption cross section for ^3He scaled to our UCN energy. We find that the total cross sections for the hydrocarbon gases are reasonably described by a function linear in the number of hydrogen atoms in the molecule.}, number={1}, journal={PHYSICAL REVIEW C}, author={Seestrom, S. J. and Adamek, E. R. and Barlow, D. and Blatnik, M. 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={2017}, month={Jan} }
 @article{wei_broussard_hoffbauer_makela_morris_tang_adamek_callahan_clayton_cude-woods_et al._2016, title={Position-sensitive detection of ultracold neutrons with an imaging camera and its implications to spectroscopy}, volume={830}, ISSN={0168-9002}, url={http://dx.doi.org/10.1016/j.nima.2016.05.058}, DOI={10.1016/j.nima.2016.05.058}, abstractNote={Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15μm has been achieved, which is equivalent to a UCN energy resolution below 2 pico-electron-volts through the relation δE=m0gδx. Here, the symbols δE, δx, m0 and g are the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This method allows different types of UCN spectroscopy and other applications.}, journal={Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment}, publisher={Elsevier BV}, author={Wei, Wanchun and Broussard, L.J. and Hoffbauer, M.A. and Makela, M. and Morris, C.L. and Tang, Z. and Adamek, E.R. and Callahan, N.B. and Clayton, S.M. and Cude-Woods, C. and et al.}, year={2016}, month={Sep}, pages={36–43} }
 @article{wang_hoffbauer_morris_callahan_adamek_bacon_blatnik_brandt_broussard_clayton_et al._2015, title={A multilayer surface detector for ultracold neutrons}, volume={798}, DOI={10.1016/j.nima.2015.07.010}, abstractNote={A multilayer surface detector for ultracold neutrons (UCNs) is described. The top $^{10}$B layer is exposed to the vacuum chamber and directly captures UCNs. The ZnS:Ag layer beneath the $^{10}$B layer is a few microns thick, which is sufficient to detect the charged particles from the $^{10}$B(n,$\alpha$)$^7$Li neutron-capture reaction, while thin enough so that ample light due to $\alpha$ and $^7$Li escapes for detection by photomultiplier tubes. One-hundred-nm thick $^{10}$B layer gives high UCN detection efficiency, as determined by the mean UCN kinetic energy, detector materials and others. Low background, including negligible sensitivity to ambient neutrons, has also been verified through pulse-shape analysis and comparisons with other existing $^3$He and $^{10}$B detectors. This type of detector has been configured in different ways for UCN flux monitoring, development of UCN guides and neutron lifetime research.}, journal={Nuclear Instruments & Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors, and Associated Equipment}, author={Wang, Z. H. and Hoffbauer, M. A. and Morris, C. L. and Callahan, N. B. and Adamek, E. R. and Bacon, J. D. and Blatnik, M. and Brandt, A. E. and Broussard, L. J. and Clayton, S. M. and et al.}, year={2015}, pages={30–35} }