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83 results on '"Pattie, R. W."'

1. YAP:Ce scintillator as an absolute ultracold neutron detector

Author

Krivoš, M., Tang, Z., Floyd, N., Morris, C. L., Blatnik, M., Cude-Woods, C., Clayton, S. M., Holley, A. T., Ito, T. M., Liu, C. -Y., Makela, M., Martinez, I. F., Navazo, A. S. C., O'Shaughnessy, C. M., Renner, E. L., Pattie, R. W., and Young, A. R.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The upcoming UCNProBe experiment at Los Alamos National Laboratory will measure the $\beta$-decay rate of free neutrons with different systematic uncertainties than previous beam-based neutron lifetime experiments. We have developed a new $^{10}$B-coated YAP:Ce scintillator whose properties are presented. The advantage of the YAP:Ce scintillator is its high Fermi potential, which reduces the probability for upscattering of ultracold neutrons, and its short decay time, which is important at high counting rates. Birks' coefficient of YAP:Ce was measured to be ($5.56^{+0.05}_{-0.30})\times 10^{-4}$ cm/MeV and light losses due to 120 nm of $^{10}$B-coating to be about 60%. The loss of light from YAP:Ce due to transmission through deuterated polystyrene scintillator was about 50%. The efficiency for counting neutrons that are captured on the $^{10}$B coating is (86.82 $\pm$ 2.61)%. Measurement with ultracold neutrons showed that YAP:Ce crystal counted 8% to 28% more UCNs compared to ZnS screen. This may be due to an uneven coating of $^{10}$B on the rough surface.

Published
2024

2. Scintillation characteristics of the EJ-299-02H scintillator

Author

Floyd, N., Hassan, Md. T., Tang, Z., Krivos, M., Blatnik, M., Clayton, S. M., Cude-Woods, C., Holley, A. T., Ito, T. M., Johnson, B. A., Liu, C. -Y., Makela, M., Morris, C. L., Navazo, A. S. C., O'Shaughnessy, C. M., Renner, E. L., Pattie, R. W., and Young, A. R.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

A study of the dead layer thickness and quenching factor of a plastic scintillator for use in ultracold neutron (UCN) experiments is described. Alpha spectroscopy was used to determine the thickness of a thin surface dead layer, and the relative light outputs from the decay of $^{241}$Am and Compton scattering of electrons were used to extract the quenching parameter. With these characteristics of the material known, the light yield of the scintillator can be calculated. The ability to make these scintillators deuterated, accompanied by its relatively thin dead layer, make it ideal for use in UCN experiment, where the light yield of decay electrons and alphas from neutron capture are critical for counting events.

Published
2023

3. Demonstration of Sub-micron UCN Position Resolution using Room-temperature CMOS Sensor

Author

Lin, S., Baldwin, J. K., Blatnik, M., Clayton, S. M., Cude-Woods, C., Currie, S. A., Filippone, B., Fries, E. M., Geltenbort, P., Holley, A. T., Li, W., Liu, C. Y., Makela, M., Morris, C. L., Musedinovic, R., O'Shaughnessy, C., Pattie, R. W., Salvat, D. J., Saunders, A., Sharapov, E. I., Singh, M., Sun, X., Tang, Z., Uhrich, W., Wei, W., Wolfe, B., Young, A. R., and Wang, Z.

Subjects
Physics - Instrumentation and Detectors, Physics - Data Analysis, Statistics and Probability
Abstract

High spatial resolution of ultracold neutron (UCN) measurement is of growing interest to UCN experiments such as UCN spectrometers, UCN polarimeters, quantum physics of UCNs, and quantum gravity. Here we utilize physics-informed deep learning to enhance the experimental position resolution and to demonstrate sub-micron spatial resolutions for UCN position measurements obtained using a room-temperature CMOS sensor, extending our previous work [1, 2] that demonstrated a position uncertainty of 1.5 microns. We explore the use of the open-source software Allpix Squared to generate experiment-like synthetic hit images with ground-truth position labels. We use physics-informed deep learning by training a fully-connected neural network (FCNN) to learn a mapping from input hit images to output hit position. The automated analysis for sub-micron position resolution in UCN detection combined with the fast data rates of current and next generation UCN sources will enable improved precision for future UCN research and applications.

Published
2023
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4. Ultracold Neutron Properties of the Eljen-299-02D deuterated scintillator

Author

Tang, Z., Watkins, E. B., Clayton, S. M., Currie, S. A., Fellers, D. E., Hassan, Md. T., Hooks, D. E., Ito, T. M., Lawrence, S. K., MacDonald, S. W. T., Makela, M., Morris, C. L., Neukirch, L. P., Saunders, A., O'Shaughnessy, C. M., Cude-Woods, C., Choi, J. H., Young, A. R., Zeck, B. A., Gonzalez, F., Liu, C. Y., Floyd, N. C., Hickerson, K. P., Holley, A. T., Johnson, B. A., Lambert, J. C., and Pattie, R. W.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

In this paper we report studies of the Fermi potential and loss per bounce of ultracold neutron (UCN) on a deuterated scintillator (Eljen-299-02D). These UCN properties of the scintillator enables a wide variety of applications in fundamental neutron research., Comment: 6 pages, 6 figures

Published
2020
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5. Final results for the neutron $\beta$-asymmetry parameter $A_0$ from the UCNA experiment

Author

Plaster, B., Adamek, E., Allgeier, B., Anaya, J., Back, H. O., Bagdasarova, Y., Berguno, D. B., Blatnik, M., Boissevain, J. G., Bowles, T. J., Broussard, L. J., Brown, M. A. -P., Carr, R., Clark, D. J., Clayton, S., Cude-Woods, C., Currie, S., Dees, E. B., Ding, X., Du, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hasan, S., Hawari, A., Hickerson, K. P., Hill, R., Hino, M., Hoagland, J., Hoedl, S. A., Hogan, G. E., Hona, B., Hong, R., Holley, A. T., Ito, T. M., Kawai, T., Kirch, K., Kitagaki, S., Knecht, A., Lamoreaux, S. K., Liu, C. -Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Meier, N., Melconian, D., Mendenhall, M. P., Moore, S. D., Morris, C. L., Mortensen, R., Nepal, S., Nouri, N., Pattie, R. W., Galvan, A. Perez, Phillips, D. G., Pichlmaier, A., Picker, R., Pitt, M. L., Ramsey, J. C., Rios, R., Russell, R., Sabourov, K., Sallaska, A. L., Salvat, D. J., Saunders, A., Schmid, R., Seestrom, S. J., Servicky, C., Sharapov, E. I., Sjue, S. K. L., Slutsky, S., Smith, D., Sondheim, W. E., Sun, X., Swank, C., Swift, G., Tatar, E., Teasdale, W., Terai, C., Tipton, B., Utsuro, M., Vogelaar, R. B., VornDick, B., Wang, Z., Wehring, B., Wexler, J., Womack, T., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., and Zeck, B. A.

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

The UCNA experiment was designed to measure the neutron $\beta$-asymmetry parameter $A_0$ using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for $A_0$ was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008--2009, 2010, and 2011--2013, which ultimately culminated in a 0.67\% precision result for $A_0$., Comment: 6 pages, 7 figures, to appear in proceedings of the International Workshop on Particle Physics at Neutron Sources 2018

Published
2019
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6. Solid deuterium surface degradation at ultracold neutron sources

Author

Anghel, A., Bailey, T. L., Bison, G., Blau, B., Broussard, L. J., Clayton, S. M., Cude-Woods, C., Daum, M., Hawari, A., Hild, N., Huffman, P., Ito, T. M., Kirch, K., Korobkina, E., Lauss, B., Leung, K., Lutz, E. M., Makela, M., Medlin, G., Morris, C. L., Pattie, R. W., Ries, D., Saunders, A., Schmidt-Wellenburg, P., Talanov, V., Young, A. R., Wehring, B., White, C., Wohlmuther, M., and Zsigmond, G.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract

Solid deuterium (sD_2) is used as an efficient converter to produce ultracold neutrons (UCN). It is known that the sD_2 must be sufficiently cold, of high purity and mostly in its ortho-state in order to guarantee long lifetimes of UCN in the solid from which they are extracted into vacuum. Also the UCN transparency of the bulk sD_2 material must be high because crystal inhomogeneities limit the mean free path for elastic scattering and reduce the extraction efficiency. Observations at the UCN sources at Paul Scherrer Institute and at Los Alamos National Laboratory consistently show a decrease of the UCN yield with time of operation after initial preparation or later treatment (`conditioning') of the sD_2. We show that, in addition to the quality of the bulk sD_2, the quality of its surface is essential. Our observations and simulations support the view that the surface is deteriorating due to a build-up of D_2 frost-layers under pulsed operation which leads to strong albedo reflections of UCN and subsequent loss. We report results of UCN yield measurements, temperature and pressure behavior of deuterium during source operation and conditioning, and UCN transport simulations. This, together with optical observations of sD_2 frost formation on initially transparent sD_2 in offline studies with pulsed heat input at the North Carolina State University UCN source results in a consistent description of the UCN yield decrease., Comment: 15 pages, 22 figures, accepted by EPJ-A

Published
2018
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7. Cerium doped yttrium aluminum perovskite scintillator as an absolute ultracold neutron detector.

Author

Krivoš, M., Floyd, N. C., Tang, Z., Morris, C. L., Blatnik, M., Clayton, S. M., Cude-Woods, C. B., Holley, A. T., Hooks, D. E., Ito, T. M., Liu, C.-Y., Makela, M., Martinez, I. F., Martinez, M. R., Navazo, A. S. C., O'Shaughnessy, C. M., Pattie, R. W., Renner, E. L., Singh, M., and Surbrook, J.

Abstract

The upcoming UCNProBe experiment at Los Alamos National Laboratory will measure the beta decay rate of free neutrons with different systematic uncertainties than previous beam-based neutron lifetime experiments. We have tested a new 10B-coated Yttrium Aluminum Perovskite (YAP:Ce) scintillator and present its properties. The advantages of the YAP:Ce scintillator include its high Fermi potential, which reduces the probability for upscattering of ultracold neutrons (UCN), and its short decay time, which increases sensitivity at high counting rates. Birks' coefficient of YAP:Ce was measured to be (5.5 6 − 0.30 + 0.05 ) × 1 0 − 4 cm/MeV. The loss of light due to the 120 nm 10B-coating was measured to be about 60%, and the loss of light from YAP:Ce due to transmission through a deuterated polystyrene scintillator was about 50%. The efficiency for neutron capture on the 10B coating was (86.8 ± 2.6)%, and a measurement using UCN showed that the YAP:Ce crystal counted 8%–28% more UCN compared to a ZnS:Ag screen. The difference may be due to the uneven coating of 10B on the rough surface of ZnS:Ag. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Scintillation characteristics of the EJ-299-02H scintillator.

Author

Floyd, N., Hassan, Md. T., Tang, Z., Krivoš, M., Blatnik, M., Cude-Woods, C., Clayton, S. M., Holley, A. T., Ito, T. M., Johnson, B. A., Liu, C.-Y., Makela, M., Morris, C. L., Navazo, A. S. C., O'Shaughnessy, C. M., Renner, E. L., Pattie, R. W., and Young, A. R.

Subjects
SCINTILLATORS, ULTRACOLD neutrons, BETA rays, COMPTON scattering, ELECTRON scattering, THRESHOLD energy
Abstract

A study of the dead layer thickness and quenching factor of a plastic scintillator for use in ultracold neutron (UCN) experiments is described. Alpha spectroscopy was used to determine the thickness of a thin surface dead layer to be 630 ± 110 nm. The relative light outputs from the decay of 241Am and Compton scattering of electrons were used to extract Birks' law coefficient, yielding a kB value of 0.087 ± 0.003 mm/MeV, consistent with some previous reports for other polystyrene-based scintillators. The results from these measurements are incorporated into the simulation to show that an energy threshold of (∼9 keV) can be achieved for the UCNProBe experiment. This low threshold enables high beta particle detection efficiency and the indirect measurement of UCN. The ability to make the scintillator deuterated, accompanied by its relatively thin dead layer, gives rise to unique applications in a wide range of UCN experiments, where it can be used to trap UCN and detect charged particles in situ. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Measurement of the neutron lifetime using a magneto-gravitational trap and in situ detection

Author

Pattie, R. W., Callahan, N. B., Cude-Woods, C., Adamek, E. R., Broussard, L. J., Clayton, S. M., Currie, S. A., Dees, E. B., Ding, X., Engel, E. M., Fellers, D. E., Fox, W., Geltenbort, P., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C.-Y., MacDonald, S. W. T., Makela, M., Morris, C. L., Ortiz, J. D., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, B., Walstrom, P. L., Wang, Z., Wei, W., Weaver, H. L., Wexler, J. W., Womack, T. L., Young, A. R., and Zeck, B. A.

Published
2018

10. Fill and dump measurement of the neutron lifetime using an asymmetric magneto-gravitational trap

Author

Cude-Woods, C., primary, Gonzalez, F. M., additional, Fries, E. M., additional, Bailey, T., additional, Blatnik, M., additional, Callahan, N. B., additional, Choi, J. H., additional, Clayton, S. M., additional, Currie, S. A., additional, Dawid, M., additional, Filippone, B. W., additional, Fox, W., additional, Geltenbort, P., additional, George, E., additional, Hayen, L., additional, Hickerson, K. P., additional, Hoffbauer, M. A., additional, Hoffman, K., additional, Holley, A. T., additional, Ito, T. M., additional, Komives, A., additional, Liu, C.-Y., additional, Makela, M., additional, Morris, C. L., additional, Musedinovic, R., additional, O'Shaughnessy, C., additional, Pattie, R. W., additional, Ramsey, J., additional, Salvat, D. J., additional, Saunders, A., additional, Sharapov, E. I., additional, Slutsky, S., additional, Su, V., additional, Sun, X., additional, Swank, C., additional, Tang, Z., additional, Uhrich, W., additional, Vanderwerp, J., additional, Walstrom, P., additional, Wang, Z., additional, Wei, W., additional, and Young, A. R., additional

Published
2022
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11. A next-generation inverse-geometry spallation-driven ultracold neutron source.

Author

Leung, K. K. H., Muhrer, G., Hügle, T., Ito, T. M., Lutz, E. M., Makela, M., Morris, C. L., Pattie, R. W., Saunders, A., and Young, A. R.

Subjects
ULTRACOLD neutrons, NEUTRON sources, PROTON beams, MAGNITUDE (Mathematics), SUPERFLUIDITY, NEUTRAL beams
Abstract

The physics model of a next-generation spallation-driven high-current ultracold neutron (UCN) source capable of delivering an extracted UCN rate of around an order of magnitude higher than the strongest proposed sources, and around three orders of magnitude higher than existing sources, is presented. This UCN-current-optimized source would dramatically improve cutting-edge UCN measurements that are currently statistically limited. A novel "Inverse Geometry" design is used with 40 l of superfluid 4 He (He-II), which acts as the converter of cold neutrons to UCNs, cooled with state-of-the-art subcooled cryogenic technology to ∼ 1.6 K. Our source design is optimized for a 100 W maximum heat load constraint on the He-II and its vessel. In this paper, we first explore modifying the Lujan Center Mark-3 target for UCN production as a benchmark. In our Inverse Geometry, the spallation target is wrapped symmetrically around the cryogenic UCN converter to permit raster scanning the proton beam over a relatively large volume of tungsten spallation target to reduce the demand on the cooling requirements, which makes it reasonable to assume that water edge-cooling only is sufficient. Our design is refined in several steps to reach a UCN production rate P UCN = 2.1 × 10 9 s − 1 under our other restriction of 1 MW maximum available proton beam power. We then study the effects of the He-II scattering kernel used as well as reductions in P UCN due to pressurization to reach P UCN = 1.8 × 10 9 s − 1 . Finally, we provide a design for the UCN extraction system that takes into account the required He-II heat transport properties and implementation of a He-II containment foil that allows UCN transmission. We estimate a total useful UCN current from our source of R use ≈ 5 × 10 8 s − 1 from an 18 cm diameter guide ∼ 5 m from the source. Under a conservative "no return" (or "single passage") approximation, this rate can produce an extracted density of > --> 1 × 10 4 UCN cm − 3 in < 1000 l external experimental volumes with a 58 Ni (335 neV) cutoff potential. [ABSTRACT FROM AUTHOR]

Published
2019
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12. New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the HIBEAM/NNBAR experiment at the European Spallation Source

Author

Addazi, A, primary, Anderson, K, additional, Ansell, S, additional, Babu, K S, additional, Barrow, J L, additional, Baxter, D V, additional, Bentley, P M, additional, Berezhiani, Z, additional, Bevilacqua, R, additional, Biondi, R, additional, Bohm, C, additional, Brooijmans, G, additional, Broussard, L J, additional, Cedercäll, J, additional, Crawford, C, additional, Dev, P S B, additional, DiJulio, D D, additional, Dolgov, A D, additional, Dunne, K, additional, Fierlinger, P, additional, Fitzsimmons, M R, additional, Fomin, A, additional, Frost, M J, additional, Gardiner, S, additional, Gardner, S, additional, Galindo-Uribarri, A, additional, Geltenbort, P, additional, Girmohanta, S, additional, Golubev, P, additional, Golubeva, E, additional, Greene, G L, additional, Greenshaw, T, additional, Gudkov, V, additional, Hall-Wilton, R, additional, Heilbronn, L, additional, Herrero-Garcia, J, additional, Holley, A, additional, Ichikawa, G, additional, Ito, T M, additional, Iverson, E, additional, Johansson, T, additional, Jönsson, L, additional, Jwa, Y-J, additional, Kamyshkov, Y, additional, Kanaki, K, additional, Kearns, E, additional, Kokai, Z, additional, Kerbikov, B, additional, Kitaguchi, M, additional, Kittelmann, T, additional, Klinkby, E, additional, Kobakhidze, A, additional, Koerner, L W, additional, Kopeliovich, B, additional, Kozela, A, additional, Kudryavtsev, V, additional, Kupsc, A, additional, Lee, Y T, additional, Lindroos, M, additional, Makkinje, J, additional, Marquez, J I, additional, Meirose, B, additional, Miller, T M, additional, Milstead, D, additional, Mohapatra, R N, additional, Morishima, T, additional, Muhrer, G, additional, Mumm, H P, additional, Nagamoto, K, additional, Nepomuceno, A, additional, Nesti, F, additional, Nesvizhevsky, V V, additional, Nilsson, T, additional, Oskarsson, A, additional, Paryev, E, additional, Pattie, R W, additional, Penttil, S, additional, Perrey, H, additional, Pokotilovski, Y N, additional, Potashnikovav, I, additional, Ramic, K, additional, Redding, C, additional, Richard, J-M, additional, Ries, D, additional, Rinaldi, E, additional, Rizzi, N, additional, Rossi, N, additional, Ruggles, A, additional, Rybolt, B, additional, Santoro, V, additional, Sarkar, U, additional, Saunders, A, additional, Senjanovic, G, additional, Serebrov, A P, additional, Shimizu, H M, additional, Shrock, R, additional, Silverstein, S, additional, Silvermyr, D, additional, Snow, W M, additional, Takibayev, A, additional, Tkachev, I, additional, Townsend, L, additional, Tureanu, A, additional, Varriano, L, additional, Vainshtein, A, additional, de Vries, J, additional, Wagner, R, additional, Woracek, R, additional, Yamagata, Y, additional, Yiu, S, additional, Young, A R, additional, Zanini, L, additional, Zhang, Z, additional, and Zimmer, O, additional

Published
2021
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13. Improved neutron lifetime measurement with UCN$��$

Author

Gonzalez, F. M., Fries, E. M., Cude-Woods, C., Bailey, T., Blatnik, M., Broussard, L. J., Callahan, N. B., Choi, J. H., Clayton, S. M., Currie, S. A., Dawid, M., Dees, E. B., Filippone, B. W., Fox, W., Geltenbort, P., George, E., Hayen, L., Hickerson, K. P., Hoffbauer, M. A., Hoffman, K., Holley, A. T., Ito, T. M., Komives, A., Liu, C. -Y., Makela, M., Morris, C. L., Musedinovic, R., O'Shaughnessy, C., Pattie, R. W., Ramsey, J., Salvat, D. J., Saunders, A., Sharapov, E. I., Slutsky, S., Su, V., Sun, X., Swank, C., Tang, Z., Uhrich, W., Vanderwerp, J., Walstrom, P., Wang, Z., Wei, W., and Young, A. R.

Subjects
Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We report an improved measurement of the free neutron lifetime $��_{n}$ using the UCN$��$ apparatus at the Los Alamos Neutron Science Center. We counted a total of approximately $38\times10^{6}$ surviving ultracold neutrons (UCN) after storing in UCN$��$'s magneto-gravitational trap over two data acquisition campaigns in 2017 and 2018. We extract $��_{n}$ from three blinded, independent analyses by both pairing long and short storage-time runs to find a set of replicate $��_{n}$ measurements and by performing a global likelihood fit to all data while self-consistently incorporating the $��$-decay lifetime. Both techniques achieve consistent results and find a value $��_{n}=877.75\pm0.28_{\text{ stat}}+0.22/-0.16_{\text{ syst}}$~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., 7 pages, 2 figures, 3 tables

Published
2021
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14. New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the HIBEAM/NNBAR experiment at the European Spallation Source

Author

Addazi, A., Anderson, K., Ansell, S., Babu, K. S., Barrow, J. L., Baxter, D., Bentley, P. M., Berezhiani, Z., Bevilacqua, R., Biondi, R., Bohm, Christian, Brooijmans, G., Broussard, L. J., Cedercäll, J., Crawford, C., Dev, P. S. B., DiJulio, D. D., Dolgov, A. D., Dunne, Katherine, Fierlinger, P., Fitzsimmons, M. R., Fomin, A., Frost, M. J., Gardiner, S., Gardner, S., Galindo-Uribarri, A., Geltenbort, P., Girmohanta, S., Golubev, P., Golubeva, E., Greene, G. L., Greenshaw, T., Gudkov, V, Hall-Wilton, R., Heilbronn, L., Herrero-Garcia, J., Holley, A., Ichikawa, G., Ito, T. M., Iverson, E., Johansson, T., Jönsson, L., Jwa, Y-J, Kamyshkov, Y., Kanaki, K., Kearns, E., Kokai, Z., Kerbikov, B., Kitaguchi, M., Kittelmann, T., Klinkby, E., Kobakhidze, A., Koerner, L. W., Kopeliovich, B., Kozela, A., Kudryavtsev, V., Kupsc, A., Lee, Y. T., Lindroos, M., Makkinje, J., Marquez, J., Meirose, Bernhard, Miller, T. M., Milstead, David, Mohapatra, R. N., Morishima, T., Muhrer, G., Mumm, H. P., Nagamoto, K., Nepomuceno, A., Nesti, F., Nesvizhevsky, V. V., Nilsson, T., Oskarsson, A., Paryev, E., Pattie, R. W., Penttil, S., Perrey, H., Pokotilovski, Y. N., Potashnikovav, I., Ramic, K., Redding, C., Richard, J-M., Ries, D., Rinaldi, E., Rizzi, N., Rossi, N., Ruggles, A., Rybolt, B., Santoro, V., Sarkar, U., Saunders, A., Senjanovic, G., Serebrov, A. P., Shimizu, H. M., Shrock, R., Silverstein, Samuel, Silvermyr, D., Snow, W. M., Takibayev, A., Tkachev, I., Townsend, L., Tureanu, A., Varriano, L., Vainshtein, A., de Vries, J., Wagner, R., Woracek, R., Yamagata, Y., Yiu, Sze Chun, Young, A. R., Zanini, L., Zhang, Z., Zimmer, O., Addazi, A., Anderson, K., Ansell, S., Babu, K. S., Barrow, J. L., Baxter, D., Bentley, P. M., Berezhiani, Z., Bevilacqua, R., Biondi, R., Bohm, Christian, Brooijmans, G., Broussard, L. J., Cedercäll, J., Crawford, C., Dev, P. S. B., DiJulio, D. D., Dolgov, A. D., Dunne, Katherine, Fierlinger, P., Fitzsimmons, M. R., Fomin, A., Frost, M. J., Gardiner, S., Gardner, S., Galindo-Uribarri, A., Geltenbort, P., Girmohanta, S., Golubev, P., Golubeva, E., Greene, G. L., Greenshaw, T., Gudkov, V, Hall-Wilton, R., Heilbronn, L., Herrero-Garcia, J., Holley, A., Ichikawa, G., Ito, T. M., Iverson, E., Johansson, T., Jönsson, L., Jwa, Y-J, Kamyshkov, Y., Kanaki, K., Kearns, E., Kokai, Z., Kerbikov, B., Kitaguchi, M., Kittelmann, T., Klinkby, E., Kobakhidze, A., Koerner, L. W., Kopeliovich, B., Kozela, A., Kudryavtsev, V., Kupsc, A., Lee, Y. T., Lindroos, M., Makkinje, J., Marquez, J., Meirose, Bernhard, Miller, T. M., Milstead, David, Mohapatra, R. N., Morishima, T., Muhrer, G., Mumm, H. P., Nagamoto, K., Nepomuceno, A., Nesti, F., Nesvizhevsky, V. V., Nilsson, T., Oskarsson, A., Paryev, E., Pattie, R. W., Penttil, S., Perrey, H., Pokotilovski, Y. N., Potashnikovav, I., Ramic, K., Redding, C., Richard, J-M., Ries, D., Rinaldi, E., Rizzi, N., Rossi, N., Ruggles, A., Rybolt, B., Santoro, V., Sarkar, U., Saunders, A., Senjanovic, G., Serebrov, A. P., Shimizu, H. M., Shrock, R., Silverstein, Samuel, Silvermyr, D., Snow, W. M., Takibayev, A., Tkachev, I., Townsend, L., Tureanu, A., Varriano, L., Vainshtein, A., de Vries, J., Wagner, R., Woracek, R., Yamagata, Y., Yiu, Sze Chun, Young, A. R., Zanini, L., Zhang, Z., and Zimmer, O.

Abstract

The violation of baryon number, , is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the Universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR program is a proposed two-stage experiment at the European Spallation Source to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron–antineutron oscillation () via mixing, neutron–antineutron oscillation via regeneration from a sterile neutron state (), and neutron disappearance (n → n'); the effective process of neutron regeneration () is also possible. The program can be used to discover and characterize mixing in the neutron, antineutron and sterile neutron sectors. The experiment addre

Published
2021
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15. New high-sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons at the European Spallation Source

Author

Addazi, A., Anderson, K., Ansell, S., Babu, K., Barrow, J., Baxter, D. V., Bentley, P. M., Berezhiani, Z., Bevilacqua, R., Bohm, C., Brooijmans, G., Broussard, J., Biondi, R., Dev, B., Crawford, C., Dolgov, A., Dunne, K., Fierlinger, P., Fitzsimmons, M. R., Fomin, A., Frost, M., Gardner, S., Galindo-Uribarri, A., Golubeva, E., Girmohanta, S., Greene, G. L., Greenshaw, T., Gudkov, V., Hall-Wilton, R., Heilbronn, L., Herrero-Garcia, J., Ito, G. Ichikawa T. M., Iverson, E., Johansson, T., Joensson, L., Jwa, Y-J., Kamyshkov, Y., Kanaki, K., Kearns, E., Kitaguchi, M., Kittelmann, T., Klinkby, E., Koerner, L. W., Kopeliovich, B., Kozela, A., Kudryatsev, V., Kupsc, A., Lee, Y., Lindroos, M., Makkinje, J., Marquez, J. I., Mohapatra, R., Meirose, B., Miller, T. M., Milstead, D., Morishima, T., Muhrer, G., Mumm, H. P., Nagamoto, K., Nesvizhevsky, V. V., Nilsson, T., Oskarsson, A., Paryev, E., Pattie, R. W., Penttil, S., Pokotilovski, Y. N., Potashnikova, I., Redding, C., Richard, J-M, Ries, D., Rinaldi, E., Ruggles, A., Rybolt, B., Santoro, V., Sarkar, U., Saunders, A., Senjanovic, G., Serebrov, A. P., Shimizu, H. M., Shrock, R., Silverstein, S., Silvermyr, D., Snow, W. M., Takibayev, A., Townsend, L., Tkachev, I., Varriano, L., Vainshtein, A., de VRies, J., Woracek, R., Yamagata, Y., Young, A. R., Zanini, L., Zhang, Z., and Zimmer, O.

Subjects
High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, Nuclear Theory, High Energy Physics::Phenomenology, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment, High Energy Physics - Experiment
Abstract

The violation of Baryon Number, $\mathcal{B}$, is an essential ingredient for the preferential creation of matter over antimatter needed to account for the observed baryon asymmetry in the universe. However, such a process has yet to be experimentally observed. The HIBEAM/NNBAR %experiment program is a proposed two-stage experiment at the European Spallation Source (ESS) to search for baryon number violation. The program will include high-sensitivity searches for processes that violate baryon number by one or two units: free neutron-antineutron oscillation ($n\rightarrow \bar{n}$) via mixing, neutron-antineutron oscillation via regeneration from a sterile neutron state ($n\rightarrow [n',\bar{n}'] \rightarrow \bar{n}$), and neutron disappearance ($n\rightarrow n'$); the effective $\Delta \mathcal{B}=0$ process of neutron regeneration ($n\rightarrow [n',\bar{n}'] \rightarrow n$) is also possible. The program can be used to discover and characterise mixing in the neutron, antineutron, and sterile neutron sectors. The experiment addresses topical open questions such as the origins of baryogenesis, the nature of dark matter, and is sensitive to scales of new physics substantially in excess of those available at colliders. A goal of the program is to open a discovery window to neutron conversion probabilities (sensitivities) by up to three orders of magnitude compared with previous searches. The opportunity to make such a leap in sensitivity tests should not be squandered. The experiment pulls together a diverse international team of physicists from the particle (collider and low energy) and nuclear physics communities, while also including specialists in neutronics and magnetics.

Published
2020

16. Final results for the neutron β-asymmetry parameter A₀ from the UCNA experiment

Author

Plaster, B., Adamek, E., Allgeier, B., Anaya, J., Back, H. O., Bagdasarova, Y., Berguno, D. B., Blatnik, M., Boissevain, J. G., Bowles, T. J., Broussard, L. J., Brown, M. A.-P., Carr, R., Clark, D. J., Clayton, S., Cude-Woods, C., Currie, S., Dees, E. B., Ding, X., Du, S., Filippone, B. W., García, A., Geltenbort, P., Hasan, S., Hawari, A., Hickerson, K. P., Hill, R., Hino, M., Hoagland, J., Hoedl, S. A., Hogan, G. E., Hona, B., Hong, R., Holley, A. T., Ito, T. M., Kawai, T., Kirch, K., Kitagaki, S., Knecht, A., Lamoreaux, S. K., Liu, C.-Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Meier, N., Melconian, D., Mendenhall, M. P., Moore, S. D., Morris, C. L., Mortensen, R., Nepal, S., Nouri, N., Pattie, R. W., Pérez Galván, A., Phillips II, D. G., Pichlmaier, A., Picker, R., Pitt, M. L., Ramsey, J. C., Rios, R., Russell, R., Sabourov, K., Sallaska, A. L., Salvat, D. J., Saunders, A., Schmid, R., Seestrom, S. J., Servicky, C., Sharapov, E. I., Sjue, S. K. L., Slutsky, S., Smith, D., Sondheim, W. E., Sun, X., Swank, C., Swift, G., Tatar, E., Teasdale, W., Terai, C., Tipton, B., Utsuro, M., Vogelaar, R. B., VornDick, B., Wang, Z., Wehring, B., Wexler, J., Womack, T., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., and Zeck, B. A.

Subjects
Physics::Instrumentation and Detectors, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A₀.

Published
2019

17. Ultracold neutron properties of the Eljen-299-02D deuterated scintillator

Author

Tang, Z., primary, Watkins, E. B., additional, Clayton, S. M., additional, Currie, S. A., additional, Fellers, D. E., additional, Hassan, Md. T., additional, Hooks, D. E., additional, Ito, T. M., additional, Lawrence, S. K., additional, MacDonald, S. W. T., additional, Makela, M., additional, Morris, C. L., additional, Neukirch, L. P., additional, Saunders, A., additional, O’Shaughnessy, C. M., additional, Cude-Woods, C., additional, Choi, J. H., additional, Young, A. R., additional, Zeck, B. A., additional, Gonzalez, F., additional, Liu, C. Y., additional, Floyd, N. C., additional, Hickerson, K. P., additional, Holley, A. T., additional, Johnson, B. A., additional, Lambert, J. C., additional, and Pattie, R. W., additional

Published
2021
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18. Search for the Neutron Decay n → X + γ, Where X is a Dark Matter Particle

Author

Tang, Z., Blatnik, M., Broussard, L. J., Choi, J. H., Clayton, S. M., Cude-Woods, C., Currie, S., Fellers, D. E., Fries, E. M., Geltenbort, P., Gonzalez, F., Hickerson, K. P., Ito, T. M., Liu, C.-Y., MacDonald, S. W. T., Makela, M., Morris, C. L., O'Shaughnessy, C. M., Pattie, R. W., Jr., Plaster, B., Salvat, D. J., Saunders, A., Wang, Z., Young, A. R., and Zeck, B. A.

Subjects
High Energy Physics::Experiment
Abstract

Fornal and Grinstein recently proposed that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods, can be explained by a previously unobserved dark matter decay mode, n → X + γ. We perform a search for this decay mode over the allowed range of energies of the monoenergetic γray for X to be dark matter. A Compton-suppressed high-purity germanium detector is used to identify γrays from neutron decay in a nickel-phosphorous-coated stainless-steel bottle. A combination of Monte Carlo and radioactive source calibrations is used to determine the absolute efficiency for detecting γ rays arising from the dark matter decay mode. We exclude the possibility of a sufficiently strong branch to explain the lifetime discrepancy with 97% confidence.

Published
2018

19. Search for the Neutron Decay n$\rightarrow$ X+$��$ where X is a dark matter particle

Author

Tang, Z., Blatnik, M., Broussard, L. J., Choi, J. H., Clayton, S. M., Cude-Woods, C., Currie, S., Fellers, D. E., Fries, E. M., Geltenbort, P., Gonzalez, F., Ito, T. M ., Liu, C. -Y., MacDonald, S. W. T., Makela, M., Morris, C. L., O'Shaughnessy, C. M., Pattie, R. W., Plaster, B., Salvat, D. J., Saunders, A., Wang, Z., Young, A. R., and Zeck, B. A.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex)
Abstract

In a recent paper submitted to Physical Review Letters, Fornal and Grinstein have suggested that the discrepancy between two different methods of neutron lifetime measurements, the beam and bottle methods can be explained by a previously unobserved dark matter decay mode, n$\rightarrow$ X+$��$ where X is a dark matter particle. We have performed a search for this decay mode over the allowed range of energies of the monoenergetic gamma ray for X to be a dark matter particle. We exclude the possibility of a sufficiently strong branch to explain the lifetime discrepancy with greater than 4 sigma confidence., 6 pages 3 figures

Published
2018
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20. Monte Carlo Simulations of Trapped Ultracold Neutrons in the UCN�� Experiment

Author

Callahan, Nathan, Liu, Chen-Yu, Gonzalez, Francisco, Adamek, Evan, Bowman, James David, Broussard, Leah, Clayton, S. M., Currie, S., Cude-Woods, C., Dees, E. B., Ding, X., Egnel, E. M., Fellers, D., Fox, W., Geltenbort, P., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., MacDonald, S. W. T., Makela, M., Morris, C. L., Ortiz, J. D., Pattie, R. W., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K. L., Tang, Z., Vanderwerp, J., Vogelaar, B., Walstrom, P. L., Wang, Z., Weaver, H., Wei, W., Wexler, J., Young, A. R., and Zeck, B. A.

Subjects
FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

In the UCN�� experiment, ultracold neutrons (UCN) are confined by magnetic fields and the Earth's gravitational field. Field-trapping mitigates the problem of UCN loss on material surfaces, which caused the largest correction in prior neutron experiments using material bottles. However, the neutron dynamics in field traps differ qualitatively from those in material bottles. In the latter case, neutrons bounce off material surfaces with significant diffusivity and the population quickly reaches a static spatial distribution with a density gradient induced by the gravitational potential. In contrast, the field-confined UCN -- whose dynamics can be described by Hamiltonian mechanics -- do not exhibit the stochastic behaviors typical of an ideal gas model as observed in material bottles. In this report, we will describe our efforts to simulate UCN trapping in the UCN�� magneto-gravitational trap. We compare the simulation output to the experimental results to determine the parameters of the neutron detector and the input neutron distribution. The tuned model is then used to understand the phase space evolution of neutrons observed in the UCN�� experiment. We will discuss the implications of chaotic dynamics on controlling the systematic effects, such as spectral cleaning and microphonic heating, for a successful UCN lifetime experiment to reach a 0.01% level of precision., 18 pages, 19 figures

Published
2018
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21. Search for dark matter decay of the free neutron from the UCNA experiment: n $\rightarrow ��+ e^+e^-$

Author

Sun, X., Adamek, E., Allgeier, B., Blatnik, M., Bowles, T. J., Broussard, L. J., Brown, M. A. -P., Carr, R., Clayton, S., Cude-Woods, C., Currie, S., Dees, E. B., Ding, X., Filippone, B. W., Garc��a, A., Geltenbort, P., Hasan, S., Hickerson, K. P., Hoagland, J., Hong, R., Hogan, G. E., Holley, A. T., Ito, T. M., Knecht, A., Liu, C. -Y., Liu, J., Makela, M., Mammei, R., Martin, J. W., Melconian, D., Mendenhall, M. P., Moore, S. D., Morris, C. L., Nepal, S., Nouri, N., Pattie, R. W., Galv��n, A. P��rez, Phillips, D. G., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Salvat, D. J., Saunders, A., Sondheim, W., Sjue, S., Slutsky, S., Swank, C., Swift, G., Tatar, E., Vogelaar, R. B., VornDick, B., Wang, Z., Wei, W., Wexler, J., Womack, T., Wrede, C., Young, A. R., and Zeck, B. A.

Subjects
FOS: Physical sciences, High Energy Physics::Experiment, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex)
Abstract

It has been proposed recently that a previously unobserved neutron decay branch to a dark matter particle ($��$) could account for the discrepancy in the neutron lifetime observed in experiments that use two different measurement techniques. One of the possible final states discussed includes a single $��$ along with an $e^{+}e^{-}$ pair. We use data from the UCNA (Ultracold Neutron Asymmetry) experiment to set limits on this decay channel. Coincident electron-like events are detected with $\sim 4��$ acceptance using a pair of detectors that observe a volume of stored Ultracold Neutrons (UCNs). The summed kinetic energy ($E_{e^{+}e^{-}}$) from such events is used to set limits, as a function of the $��$ mass, on the branching fraction for this decay channel. For $��$ masses consistent with resolving the neutron lifetime discrepancy, we exclude this as the dominant dark matter decay channel at $\gg~5��$ level for $100~\text{keV} < E_{e^{+}e^{-}} < 644~\text{keV}$. If the $��+e^{+}e^{-}$ final state is not the only one, we set limits on its branching fraction of $< 10^{-4}$ for the above $E_{e^{+}e^{-}}$ range at $> 90\%$ confidence level., 5 pages, 5 figures

Published
2018
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22. Monte Carlo simulations of trapped ultracold neutrons in the UCNτ experiment

Author

Callahan, Nathan, primary, Liu, Chen-Yu, additional, Gonzalez, Francisco, additional, Adamek, E., additional, Bowman, J. D., additional, Broussard, L., additional, Clayton, S. M., additional, Currie, S., additional, Cude-Woods, C., additional, Dees, E. B., additional, Ding, X., additional, Fox, W., additional, Geltenbort, P., additional, Hickerson, K. P., additional, Hoffbauer, M. A., additional, Holley, A. T., additional, Komives, A., additional, MacDonald, S. W. T., additional, Makela, M., additional, Morris, C. L., additional, Ortiz, J. D., additional, Pattie, R. W., additional, Ramsey, J., additional, Salvat, D. J., additional, Saunders, A., additional, Sharapov, E. I., additional, Sjue, S. K. L., additional, Tang, Z., additional, Vanderwerp, J., additional, Vogelaar, B., additional, Walstrom, P. L., additional, Wang, Z., additional, Weaver, H., additional, Wei, W., additional, Wexler, J., additional, and Young, A. R., additional

Published
2019
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23. Measurement of the neutron lifetime using an asymmetric magneto- gravitational trap and in situ detection

Author

Pattie, R. W., Callahan, N. B., Cude-Woods, C., Adamek, E. R., Broussard, L. J., Clayton, S. M., Currie, S. A., Dees, E. B., Ding, X., Engel, E. M., Fellers, D. E., Fox, W., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C. -Y., MacDonald, S. W. T., Makela, M., Morris, C. L., Ortiz, J. D., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, B., Walstrom, P. L., Wang, Z., Wei, W., Weaver, H. L., Wexler, J. W., Womack, T. L., Young, A. R., and Zeck, B. A.

Subjects
Nuclear Theory (nucl-th), High Energy Physics - Experiment (hep-ex), Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract

The precise value of the mean neutron lifetime, $\tau_n$, plays an important role in nuclear and particle physics and cosmology. It is a key input for predicting the ratio of protons to helium atoms in the primordial universe and is used to search for new physics beyond the Standard Model of particle physics. There is a 3.9 standard deviation discrepancy between $\tau_n$ measured by counting the decay rate of free neutrons in a beam (887.7 $\pm$ 2.2 s) and by counting surviving ultracold neutrons stored for different storage times in a material trap (878.5$\pm$0.8 s). The experiment described here eliminates loss mechanisms present in previous trap experiments by levitating polarized ultracold neutrons above the surface of an asymmetric storage trap using a repulsive magnetic field gradient so that the stored neutrons do not interact with material trap walls and neutrons in quasi-stable orbits rapidly exit the trap. As a result of this approach and the use of a new in situ neutron detector, the lifetime reported here (877.7 $\pm$ 0.7 (stat) +0.4/-0.2 (sys) s) is the first modern measurement of $\tau_n$ that does not require corrections larger than the quoted uncertainties., Comment: 9 pages, 3 figures, 2 tables

Published
2017

24. New result for the neutron $��$-asymmetry parameter $A_0$ from UCNA

Author

Brown, M. A. -P., Dees, E. B., Adamek, E., Allgeier, B., Blatnik, M., Bowles, T. J., Broussard, L. J., Carr, R., Clayton, S., Cude-Woods, C., Currie, S., Ding, X., Filippone, B. W., Garcia, A., Geltenbort, P., Hasan, S., Hickerson, K. P., Hoagland, J., Hong, R., Hogan, G. E., Holley, A. T., Ito, T. M., Knecht, A., Liu, C. -Y., Liu, J., Makela, M., Martin, J. W., Melconian, D., Mendenhall, M. P., Moore, S. D., Morris, C. L., Nepal, S., Nouri, N., Pattie, R. W., Perez-Galvan, A., Phillips, D. G., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Salvat, D. J., Saunders, A., Sondheim, W., Seestrom, S. J., Sjue, S., Slutsky, S., Sun, X., Swank, C., Swift, G., Tatar, E., Vogelaar, R. B., VornDick, B., Wang, Z., Wexler, J., Womack, T., Wrede, C., Young, A. R., and Zeck, B. A.

Subjects
FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The neutron $��$-decay asymmetry parameter $A_0$ defines the correlation between the spin of the neutron and the momentum of the emitted electron, which determines $��=\frac{g_{A}}{g_{V}}$, the ratio of the axial-vector to vector weak coupling constants. The UCNA Experiment, located at the Ultracold Neutron facility at the Los Alamos Neutron Science Center, is the first to measure such a correlation coefficient using ultracold neutrons (UCN). Following improvements to the systematic uncertainties and increased statistics, we report the new result $A_0 = -0.12054(44)_{\mathrm{stat}}(68)_{\mathrm{syst}}$ which yields $��\equiv \frac{g_{A}}{g_{V}}=-1.2783(22)$. Combination with the previous UCNA result and accounting for correlated systematic uncertainties produces $A_0=-0.12015(34)_{\mathrm{stat}}(63)_{\mathrm{syst}}$ and $��\equiv \frac{g_{A}}{g_{V}}=-1.2772(20)$., 9 pages, 7 figures, updated to as-published version

Published
2017
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25. Solid deuterium surface degradation at ultracold neutron sources

Author

Anghel, A., primary, Bailey, T. L., additional, Bison, G., additional, Blau, B., additional, Broussard, L. J., additional, Clayton, S. M., additional, Cude-Woods, C., additional, Daum, M., additional, Hawari, A., additional, Hild, N., additional, Huffman, P., additional, Ito, T. M., additional, Kirch, K., additional, Korobkina, E., additional, Lauss, B., additional, Leung, K., additional, Lutz, E. M., additional, Makela, M., additional, Medlin, G., additional, Morris, C. L., additional, Pattie, R. W., additional, Ries, D., additional, Saunders, A., additional, Schmidt-Wellenburg, P., additional, Talanov, V., additional, Young, A. R., additional, Wehring, B., additional, White, C., additional, Wohlmuther, M., additional, and Zsigmond, G., additional

Published
2018
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26. Search for the Neutron Decay n→X+γ , Where X is a Dark Matter Particle

Author

Tang, Z., primary, Blatnik, M., additional, Broussard, L. J., additional, Choi, J. H., additional, Clayton, S. M., additional, Cude-Woods, C., additional, Currie, S., additional, Fellers, D. E., additional, Fries, E. M., additional, Geltenbort, P., additional, Gonzalez, F., additional, Hickerson, K. P., additional, Ito, T. M., additional, Liu, C.-Y., additional, MacDonald, S. W. T., additional, Makela, M., additional, Morris, C. L., additional, O’Shaughnessy, C. M., additional, Pattie, R. W., additional, Plaster, B., additional, Salvat, D. J., additional, Saunders, A., additional, Wang, Z., additional, Young, A. R., additional, and Zeck, B. A., additional

Published
2018
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27. Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment

Author

Ito, T. M., primary, Adamek, E. R., additional, Callahan, N. B., additional, Choi, J. H., additional, Clayton, S. M., additional, Cude-Woods, C., additional, Currie, S., additional, Ding, X., additional, Fellers, D. E., additional, Geltenbort, P., additional, Lamoreaux, S. K., additional, Liu, C.-Y., additional, MacDonald, S., additional, Makela, M., additional, Morris, C. L., additional, Pattie, R. W., additional, Ramsey, J. C., additional, Salvat, D. J., additional, Saunders, A., additional, Sharapov, E. I., additional, Sjue, S., additional, Sprow, A. P., additional, Tang, Z., additional, Weaver, H. L., additional, Wei, W., additional, and Young, A. R., additional

Published
2018
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28. A new method for measuring the neutron lifetime using an in situ neutron detector

Author

Morris, C. L., Adamek, E. R., Broussard, L. J., Callahan, N. B., Clayton, S. M., Cude-Woods, C., Currie, S. A., Ding, X., Fox, W., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C. Y., Makela, M., Pattie, R. W., Jr., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, R. Bruce, Walstrom, P. L., Wang, Z., Wei, Wanchun, Wexler, J. W., Womack, T. L., Young, A. R., Zeck, B. A., Morris, C. L., Adamek, E. R., Broussard, L. J., Callahan, N. B., Clayton, S. M., Cude-Woods, C., Currie, S. A., Ding, X., Fox, W., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C. Y., Makela, M., Pattie, R. W., Jr., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, R. Bruce, Walstrom, P. L., Wang, Z., Wei, Wanchun, Wexler, J. W., Womack, T. L., Young, A. R., and Zeck, B. A.

Abstract

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. (C) 2017 Author(s).

Published
2017
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29. A new method for measuring the neutron lifetime using an in situ neutron detector

Author

Physics, Morris, C. L., Adamek, E. R., Broussard, L. J., Callahan, N. B., Clayton, S. M., Cude-Woods, C., Currie, S. A., Ding, X., Fox, W., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C. Y., Makela, M., Pattie, R. W., Jr., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, R. Bruce, Walstrom, P. L., Wang, Z., Wei, Wanchun, Wexler, J. W., Womack, T. L., Young, A. R., Zeck, B. A., Physics, Morris, C. L., Adamek, E. R., Broussard, L. J., Callahan, N. B., Clayton, S. M., Cude-Woods, C., Currie, S. A., Ding, X., Fox, W., Hickerson, K. P., Hoffbauer, M. A., Holley, A. T., Komives, A., Liu, C. Y., Makela, M., Pattie, R. W., Jr., Ramsey, J., Salvat, D. J., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sjue, S. K., Tang, Z., Vanderwerp, J., Vogelaar, R. Bruce, Walstrom, P. L., Wang, Z., Wei, Wanchun, Wexler, J. W., Womack, T. L., Young, A. R., and Zeck, B. A.

Abstract

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. (C) 2017 Author(s).

Published
2017

30. Detection System for Neutron $��$ Decay Correlations in the UCNB and Nab experiments

Author

Broussard, L. J., Zeck, B. A., Adamek, E. R., Bae��ler, S., Birge, N., Blatnik, M., Bowman, J. D., Brandt, A. E., Brown, M., Burkhart, J., Callahan, N. B., Clayton, S. M., Crawford, C., Cude-Woods, C., Currie, S., Dees, E. B., Ding, X., Fomin, N., Frlez, E., Fry, J., Gray, F. E., Hasan, S., Hickerson, K. P., Hoagland, J., Holley, A. T., Ito, T. M., Klein, A., Li, H., Liu, C. -Y., Makela, M. F., McGaughey, P. L., Mirabal-Martinez, J., Morris, C. L., Ortiz, J. D., Pattie, R. W., Penttil��, S. I., Plaster, B., Po��ani��, D., Ramsey, J. C., Salas-Bacci, A., Salvat, D. J., Saunders, A., Seestrom, S. J., Sjue, S. K. L., Sprow, A. P., Tang, Z., Vogelaar, R. B., Vorndick, B., Wang, Z., Wei, W., Wexler, J., Wilburn, W. S., Womack, T. L., and Young, A. R.

Subjects
Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We describe a detection system designed for precise measurements of angular correlations in neutron $��$ 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 $��$ 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 $��$ particles and recoil protons from neutron $��$ decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments, to determine the neutron $��$ decay parameters $B$, $a$, and $b$., Copyright 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Published
2016
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31. A new method for measuring the neutron lifetime using anin situneutron detector

Author

Morris, C. L., primary, Adamek, E. R., additional, Broussard, L. J., additional, Callahan, N. B., additional, Clayton, S. M., additional, Cude-Woods, C., additional, Currie, S. A., additional, Ding, X., additional, Fox, W., additional, Hickerson, K. P., additional, Hoffbauer, M. A., additional, Holley, A. T., additional, Komives, A., additional, Liu, C.-Y., additional, Makela, M., additional, Pattie, R. W., additional, Ramsey, J., additional, Salvat, D. J., additional, Saunders, A., additional, Seestrom, S. J., additional, Sharapov, E. I., additional, Sjue, S. K., additional, Tang, Z., additional, Vanderwerp, J., additional, Vogelaar, B., additional, Walstrom, P. L., additional, Wang, Z., additional, Wei, Wanchun, additional, Wexler, J. W., additional, Womack, T. L., additional, Young, A. R., additional, and Zeck, B. A., additional

Published
2017
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32. Total cross sections for ultracold neutrons scattered from gases

Author

Seestrom, S. J., primary, Adamek, E. R., additional, Barlow, D., additional, Blatnik, M., additional, Broussard, L. J., additional, Callahan, N. B., additional, Clayton, S. M., additional, Cude-Woods, C., additional, Currie, S., additional, Dees, E. B., additional, Fox, W., additional, Hoffbauer, M., additional, Hickerson, K. P., additional, Holley, A. T., additional, Liu, C.-Y., additional, Makela, M., additional, Medina, J., additional, Morley, D. J., additional, Morris, C. L., additional, Pattie, R. W., additional, Ramsey, J., additional, Roberts, A., additional, Salvat, D. J., additional, Saunders, A., additional, Sharapov, E. I., additional, Sjue, S. K. L., additional, Slaughter, B. A., additional, Walstrom, P. L., additional, Wang, Z., additional, Wexler, J., additional, Womack, T. L., additional, Young, A. R., additional, Vanderwerp, J., additional, and Zeck, B. A., additional

Published
2017
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33. Measurement of the Half-Life of the T=1/2 Mirror Decay of Ne-19 and its Implication on Physics Beyond the Standard Model

Author

Broussard, L. J., Back, H. O., Boswell, M. S., Crowell, A. S., Dendooven, P., Giri, G. S., Howell, C. R., Kidd, M. F., Jungmann, K., Kruithof, W. L., Mol, A., Onderwater, C. J. G., Pattie, R. W., Shidling, P. D., Sohani, M., van der Hoek, D. J., Rogachevskiy, A, Traykov, E., Versolato, O. O., Willmann, L., Wilschut, H. W., Young, A. R., Research unit Medical Physics, and Precision Frontier

Subjects
LIVES
Abstract

The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.

Published
2014

34. Measurement of the Half-Life of the T = 1 2 Mirror Decay of Ne 19 and its Implication on Physics Beyond the Standard Model

Author

Giri, G. S., Pattie, R. W., Kidd, M. F., Rogachevskiy, A., Sohani, M., Crowell, A. S., Dendooven, P., Versolato, O. O., Young, A. R., Willmann, L., Boswell, M. S., Van Der Hoek, D. J., Back, H. O., Broussard, L. J., Wilschut, H. W., Traykov, E., Mol, A., Shidling, P. D., Kruithof, W. L., Howell, C. R., Onderwater, C. J.G., and Jungmann, K.

Abstract

The 1+/2 -> 1+/2 superallowed mixed mirror decay of Ne-19 to F-19 is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T-1/2 = 17.2832 +/- 0.0051((stat)) +/- 0.0066((syst)) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.

Published
2014
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35. Measurement of the half-life of the T=$\frac{1}{2}$ mirror decay of $^{19}$Ne and its implication on physics beyond the standard model

Author

Broussard, L. J., Back, H. O., Boswell, M. S., Crowell, A. S., Dendooven, P., Giri, G. S., Howell, C. R., Kidd, M. F., Jungmann, K., Kruithof, W. L., Mol, A., Onderwater, C. J. G., Pattie, R. W., Shidling, P. D., Sohani, M., van der Hoek, D. J., Rogachevskiy, A., Traykov, E., Versolato, O. O., Willmann, L., Wilschut, H. W., and Young, A. R.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The $\frac{1}{2}^+ \rightarrow \frac{1}{2}^+$ superallowed mixed mirror decay of $^{19}$Ne to $^{19}$F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be $T_{1/2}$ = $17.2832 \pm 0.0051_{(stat)}$ $\pm 0.0066_{(sys)}$ s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed., 5 pages, 3 figures, 1 table

Published
2013

37. Neutron-Antineutron Oscillations: A Snowmass 2013 White Paper

Author

Babu, K., Banerjee, S., Baxter, D. V., Berezhiani, Z., Bergevin, M., Bhattacharya, S., Brice, S., Burgess, T. W., Castellanos, L., Chattopadhyay, S., Chen, M-C., Coppola, C. E., Cowsik, R., Crabtree, J. A., Das, P., Dees, E. B., Dolgov, A., Dvali, G., Ferguson, P., Frost, M., Gabriel, T., Gal, A., Gallmeier, F., Ganezer, K., Golubeva, E., Graves, V. B., Greene, G., Handler, T., Hartfiel, B., Hawari, A., Heilbronn, L., Johnson, C., Kamyshkov, Y., Kerbikov, B., Kitaguchi, M., Kopeliovich, B. Z., Kopeliovich, V. B., Korsch, W., Kuzmin, V., Liu, C-Y., McGaughey, P., Mocko, M., Mohapatra, R., Mokhov, N., Muhrer, G., Mumm, P., Okun, L., Pattie, R. W., Phillips, D. G., Quigg, C., Ramberg, E., Ray, A., Roy, A., Ruggles, A., Sarkar, U., Saunders, A., Serebrov, A. P., Shimizu, H. M., Shrock, R., Sikdar, A. K., Sjue, S., Snow, W. M., Soha, A., Spanier, S., Striganov, S., Townsend, L., Tschirhart, R., Vainshtein, A., Van Kooten, R., Wang, Z., Wehring, B., and Young, A. R.

Subjects
High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex), Nuclear Experiment, High Energy Physics - Experiment
Abstract

This paper summarizes discussions of the theoretical developments and the studies performed by the NNbarX collaboration for the 2013 Snowmass Community Summer Study., A white paper for the 2013 Snowmass Community Summer Study

Published
2013

38. Measurement of the neutron $��$-asymmetry parameter $A_0$ with ultracold neutrons

Author

UCNA Collaboration, Plaster, B., Rios, R., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, R., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Holley, A. T., Ito, T. M., Liu, C. -Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Galvan, A. Perez, Pitt, M. L., Ramsey, J. C., Russell, R., Saunders, A., Schmid, R., Seestrom, S. J., Sjue, S., Sondheim, W. E., Tatar, E., Tipton, B., Vogelaar, R. B., VornDick, B., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., and Yuan, J.

Subjects
Physics::Instrumentation and Detectors, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We present a detailed report of a measurement of the neutron $��$-asymmetry parameter $A_0$, the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T $2 \times 2��$ solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report $A_0 = -0.11966 \pm 0.00089_{-0.00140} ^{+0.00123}$, from which we extract a value for the ratio of the weak axial-vector and vector coupling constants of the nucleon, $��= g_A/g_V = -1.27590 \pm 0.00239_{-0.00377}^{+0.00331}$. Complete details of the analysis are presented., 54 pages, 41 figures, submitted to Phys. Rev. C

Published
2012
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39. First Measurement of the Neutron $��$-Asymmetry with Ultracold Neutrons

Author

Pattie, R. W.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We report the first measurement of angular correlation parameters in neutron $��$-decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for $\sim 30$ s in a Cu decay volume. The $\vec��_n \cdot \vec{B}$ potential of a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage (AFP) spin-flipper and enter a decay volume, situated within a 1 T, $2 \times 2��$ superconducting solenoidal spectrometer. We determine a value for the $��$-asymmetry parameter $A_0$, proportional to the angular correlation between the neutron polarization and the electron momentum, of $A_0 = -0.1138 \pm 0.0051$., 4 pages, 2 figures, 1 table, submitted to Phys. Rev. Lett

Published
2008
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40. Measurement of the Half-Life of theT=12Mirror Decay ofNe19and its Implication on Physics Beyond the Standard Model

Author

Broussard, L. J., primary, Back, H. O., additional, Boswell, M. S., additional, Crowell, A. S., additional, Dendooven, P., additional, Giri, G. S., additional, Howell, C. R., additional, Kidd, M. F., additional, Jungmann, K., additional, Kruithof, W. L., additional, Mol, A., additional, Onderwater, C. J. G., additional, Pattie, R. W., additional, Shidling, P. D., additional, Sohani, M., additional, van der Hoek, D. J., additional, Rogachevskiy, A., additional, Traykov, E., additional, Versolato, O. O., additional, Willmann, L., additional, Wilschut, H. W., additional, and Young, A. R., additional

Published
2014
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41. Precision measurement of the neutron beta-decay asymmetry

Author

Mendenhall, M. P., Pattie, R. W., Bagdasarova, Y., Berguno, D. B., Broussard, L. J., Carr, Rachel E., Currie, S., Ding, X., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Holley, A. T., Hong, R., Ito, T. M., Knecht, A., Liu, C. Y., Liu, J. L., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Moore, S. D., Morris, C. L., Galvan, A. P., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Young, A. R., Zeck, B. A., Ucna Collaboration, Mendenhall, M. P., Pattie, R. W., Bagdasarova, Y., Berguno, D. B., Broussard, L. J., Carr, Rachel E., Currie, S., Ding, X., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Holley, A. T., Hong, R., Ito, T. M., Knecht, A., Liu, C. Y., Liu, J. L., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Moore, S. D., Morris, C. L., Galvan, A. P., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Young, A. R., Zeck, B. A., and Ucna Collaboration

Abstract

A new measurement of the neutron beta-decay asymmetry A(0) has been carried out by the UCNA Collaboration using polarized ultracold neutrons (UCNs) from the solid deuterium UCN source at the Los Alamos Neutron Science Center. Improvements in the experiment have led to reductions in both statistical and systematic uncertainties leading to A(0) = -0.11954(55)(stat)(98)(syst), corresponding to the ratio of axial-vector to vector coupling lambda = g(A)/g(V) = -1.2756(30).

Published
2013
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42. Precision measurement of the neutron beta-decay asymmetry

Author

Physics, Mendenhall, M. P., Pattie, R. W., Bagdasarova, Y., Berguno, D. B., Broussard, L. J., Carr, Rachel E., Currie, S., Ding, X., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Holley, A. T., Hong, R., Ito, T. M., Knecht, A., Liu, C. Y., Liu, J. L., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Moore, S. D., Morris, C. L., Galvan, A. P., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Young, A. R., Zeck, B. A., Ucna Collaboration, Physics, Mendenhall, M. P., Pattie, R. W., Bagdasarova, Y., Berguno, D. B., Broussard, L. J., Carr, Rachel E., Currie, S., Ding, X., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Holley, A. T., Hong, R., Ito, T. M., Knecht, A., Liu, C. Y., Liu, J. L., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Moore, S. D., Morris, C. L., Galvan, A. P., Picker, R., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Saunders, A., Seestrom, S. J., Sharapov, E. I., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Young, A. R., Zeck, B. A., and Ucna Collaboration

Abstract

A new measurement of the neutron beta-decay asymmetry A(0) has been carried out by the UCNA Collaboration using polarized ultracold neutrons (UCNs) from the solid deuterium UCN source at the Los Alamos Neutron Science Center. Improvements in the experiment have led to reductions in both statistical and systematic uncertainties leading to A(0) = -0.11954(55)(stat)(98)(syst), corresponding to the ratio of axial-vector to vector coupling lambda = g(A)/g(V) = -1.2756(30).

Published
2013

43. Performance of the Los Alamos National Laboratory spallation-driven solid-deuterium ultra-cold neutron source

Author

Physics, Saunders, A., Makela, M., Bagdasarova, Y., Back, H. O., Boissevain, J. G., Broussard, L. J., Bowles, T. J., Carr, Rachel E., Currie, S. A., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hill, R. E., Hoagland, J., Hoedl, S. A., Holley, A. T., Hogan, G., Ito, T. M., Lamoreaux, Steve, Liu, Chen-Yu, Liu, J., Mammei, R. R., Martin, J., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R. N., Pattie, R. W., Jr., Pitt, M., Plaster, B., Ramsey, J., Rios, R., Sallaska, A. L., Seestrom, S. J., Sharapov, E. I., Sjue, S., Sondheim, W. E., Teasdale, W., Young, A. R., VornDick, B., Vogelaar, R. Bruce, Wang, Z., Xu, Yanping, Physics, Saunders, A., Makela, M., Bagdasarova, Y., Back, H. O., Boissevain, J. G., Broussard, L. J., Bowles, T. J., Carr, Rachel E., Currie, S. A., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hill, R. E., Hoagland, J., Hoedl, S. A., Holley, A. T., Hogan, G., Ito, T. M., Lamoreaux, Steve, Liu, Chen-Yu, Liu, J., Mammei, R. R., Martin, J., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R. N., Pattie, R. W., Jr., Pitt, M., Plaster, B., Ramsey, J., Rios, R., Sallaska, A. L., Seestrom, S. J., Sharapov, E. I., Sjue, S., Sondheim, W. E., Teasdale, W., Young, A. R., VornDick, B., Vogelaar, R. Bruce, Wang, Z., and Xu, Yanping

Abstract

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 similar to 1500 cm(3). (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770063]

Published
2013

44. Upscattering of ultracold neutrons from the polymer [C6H12]n

Author

Sharapov, E. I., primary, Morris, C. L., additional, Makela, M., additional, Saunders, A., additional, Adamek, Evan R., additional, Broussard, L. J., additional, Cude-Woods, C. B., additional, Fellers, Deion E., additional, Geltenbort, Peter, additional, Hartl, M., additional, Hasan, S. I., additional, Hickerson, K. P., additional, Hogan, G., additional, Holley, A. T., additional, Lavelle, C. M., additional, Liu, Chen-Yu, additional, Mendenhall, M. P., additional, Ortiz, J., additional, Pattie, R. W., additional, Phillips, D. G., additional, Ramsey, J., additional, Salvat, D. J., additional, Seestrom, S. J., additional, Shaw, E., additional, Sjue, Sky, additional, Sondheim, W. E., additional, VornDick, B., additional, Wang, Z., additional, Womack, T. L., additional, Young, A. R., additional, and Zeck, B. A., additional

Published
2013
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45. Measurement of the neutron beta-asymmetry parameter A(0) with ultracold neutrons

Author

Plaster, B., Rios, R., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Holley, A. T., Ito, T. M., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Galvan, A. P., Pitt, M. L., Ramsey, J. C., Russell, R., Saunders, A., Schmid, R., Seestrom, S. J., Sjue, S., Sondheim, W. E., Tatar, E., Tipton, B., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., Ucna Collaboration, Plaster, B., Rios, R., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Holley, A. T., Ito, T. M., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Galvan, A. P., Pitt, M. L., Ramsey, J. C., Russell, R., Saunders, A., Schmid, R., Seestrom, S. J., Sjue, S., Sondheim, W. E., Tatar, E., Tipton, B., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., and Ucna Collaboration

Abstract

We present a detailed report of a measurement of the neutron beta-asymmetry parameter A(0), the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T 2 x 2 pi solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report A(0) = -0.11966 +/- 0.00089(-0.00140)(+0.00123), from lambda = g(A)/g(V) = -1.27590 +/- 0.00239(-0.00377)(+0.00331). Complete details of the analysis are presented.

Published
2012
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46. Measurement of the neutron beta-asymmetry parameter A(0) with ultracold neutrons

Author

Physics, Plaster, B., Rios, R., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Holley, A. T., Ito, T. M., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Galvan, A. P., Pitt, M. L., Ramsey, J. C., Russell, R., Saunders, A., Schmid, R., Seestrom, S. J., Sjue, S., Sondheim, W. E., Tatar, E., Tipton, B., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., Ucna Collaboration, Physics, Plaster, B., Rios, R., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Holley, A. T., Ito, T. M., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Galvan, A. P., Pitt, M. L., Ramsey, J. C., Russell, R., Saunders, A., Schmid, R., Seestrom, S. J., Sjue, S., Sondheim, W. E., Tatar, E., Tipton, B., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Xu, Y. P., Yan, H., Young, A. R., Yuan, J., and Ucna Collaboration

Abstract

We present a detailed report of a measurement of the neutron beta-asymmetry parameter A(0), the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T 2 x 2 pi solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report A(0) = -0.11966 +/- 0.00089(-0.00140)(+0.00123), from lambda = g(A)/g(V) = -1.27590 +/- 0.00239(-0.00377)(+0.00331). Complete details of the analysis are presented.

Published
2012

47. A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment

Author

Physics, Holley, A. T., Broussard, L. J., Davis, J. L., Hickerson, K., Ito, T. M., Liu, C. Y., Lyles, J. T. M., Makela, M., Mammei, R. R., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Rios, R., Saunders, A., Young, A. R., Physics, Holley, A. T., Broussard, L. J., Davis, J. L., Hickerson, K., Ito, T. M., Liu, C. Y., Lyles, J. T. M., Makela, M., Mammei, R. R., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pattie, R. W., Rios, R., Saunders, A., and Young, A. R.

Abstract

The UCNA collaboration is making a precision measurement of the beta 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 (epsilon) over bar = 0.9985(4). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4732822]

Published
2012

48. Determination of the Axial-Vector Weak Coupling Constant with Ultracold Neutrons

Author

Physics, Liu, J., Mendenhall, M. P., Holley, A. T., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Ito, T. M., Liu, C. Y., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Morris, C. L., Pattie, R. W., Galvan, A. P., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Russell, R., Saunders, A., Seestrom, S. J., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Yan, H., Young, A. R., Ucna Collaboration, Physics, Liu, J., Mendenhall, M. P., Holley, A. T., Back, H. O., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clayton, S., Currie, S., Filippone, B. W., Garcia, A., Geltenbort, P., Hickerson, K. P., Hoagland, J., Hogan, G. E., Hona, B., Ito, T. M., Liu, C. Y., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Morris, C. L., Pattie, R. W., Galvan, A. P., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Russell, R., Saunders, A., Seestrom, S. J., Sondheim, W. E., Tatar, E., Vogelaar, R. Bruce, VornDick, B., Wrede, C., Yan, H., Young, A. R., and Ucna Collaboration

Abstract

A precise measurement of the neutron decay beta asymmetry A(0) has been carried out using polarized ultracold neutrons from the pulsed spallation ultracold neutron source at the Los Alamos Neutron Science Center. Combining data obtained in 2008 and 2009, we report A(0) = -0.119 66 +/- 0.000 89(-0.001 40)(+0.001 23), from which we determine the ratio of the axial- vector to vector weak coupling of the nucleon gA/gV = -1.275 90(-0.004 45)(+0.004 09).

Published
2010

49. First Measurement of the Neutron beta Asymmetry with Ultracold Neutrons

Author

Physics, Pattie, R. W., Anaya, J., Back, H. O., Boissevain, J. G., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clark, D. J., Currie, S., Du, S., Filippone, B. W., Geltenbort, P., Garcia, A., Hawari, A., Hickerson, K. P., Hill, R., Hino, M., Hoedl, S. A., Hogan, G. E., Holley, A. T., Ito, T. M., Kawai, T., Kirch, K., Kitagaki, S., Lamoreaux, S. K., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Meier, N., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pichlmaier, A., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Sabourov, K., Sallaska, A. L., Saunders, A., Schmid, R., Seestrom, S. J., Servicky, C., Sjue, S. K. L., Smith, D., Sondheim, W. E., Tatar, E., Teasdale, W., Terai, C., Tipton, B., Utsuro, M., Vogelaar, R. Bruce, Wehring, B. W., Xu, Y. P., Young, A. R., Yuan, J., Ucna Collaboration, Physics, Pattie, R. W., Anaya, J., Back, H. O., Boissevain, J. G., Bowles, T. J., Broussard, L. J., Carr, Rachel E., Clark, D. J., Currie, S., Du, S., Filippone, B. W., Geltenbort, P., Garcia, A., Hawari, A., Hickerson, K. P., Hill, R., Hino, M., Hoedl, S. A., Hogan, G. E., Holley, A. T., Ito, T. M., Kawai, T., Kirch, K., Kitagaki, S., Lamoreaux, S. K., Liu, C. Y., Liu, J., Makela, M., Mammei, R. R., Martin, J. W., Melconian, D., Meier, N., Mendenhall, M. P., Morris, C. L., Mortensen, R., Pichlmaier, A., Pitt, M. L., Plaster, B., Ramsey, J. C., Rios, R., Sabourov, K., Sallaska, A. L., Saunders, A., Schmid, R., Seestrom, S. J., Servicky, C., Sjue, S. K. L., Smith, D., Sondheim, W. E., Tatar, E., Teasdale, W., Terai, C., Tipton, B., Utsuro, M., Vogelaar, R. Bruce, Wehring, B. W., Xu, Y. P., Young, A. R., Yuan, J., and Ucna Collaboration

Abstract

We report the first measurement of an angular correlation parameter in neutron beta decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for similar to 30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in a 2 x 2 pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A(0) = -0.1138 +/- 0.0046 +/- 0.0021.

Published
2009

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