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Title: Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment

Abstract

We report the ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was 184(32) UCN / cm 3, a fourfold increase from the highest previously reported. Finally, the polarized UCN density stored in an external chamber was measured to be 39(7) UCN / cm 3, which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of σ(d n) = 3 × 10 -27 e cm.

Authors:
 [1];  [2];  [2];  [3];  [1];  [4];  [1];  [5];  [1];  [6];  [7];  [8];  [1];  [1];  [1];  [1];  [1];  [2];  [1];  [9] more »;  [1];  [10];  [1];  [1];  [1];  [3] « less
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Indiana Univ., Bloomington, IN (United States)
  3. North Carolina State Univ., Raleigh, NC (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); North Carolina State Univ., Raleigh, NC (United States)
  5. Virginia Polytechnic Institute and State University, Blacksburg, VA (United States)
  6. Institut Laue-Langevin, Grenoble (France)
  7. Yale Univ., New Haven, CT (United States)
  8. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Indiana Univ., Bloomington, IN (United States)
  9. Joint Institute of Nuclear Research, Dubna, Moscow Region (Russia)
  10. Univ. of Kentucky, Lexington, KY (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1422926
Alternate Identifier(s):
OSTI ID: 1418395; OSTI ID: 1481656
Report Number(s):
LA-UR-17-29313
Journal ID: ISSN 2469-9985; PRVCAN; TRN: US1801672
Grant/Contract Number:  
AC52-06NA25396; FG02-97ER41042; 20140015DR; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review C
Additional Journal Information:
Journal Volume: 97; Journal Issue: 1; Journal ID: ISSN 2469-9985
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Atomic and Nuclear Physics

Citation Formats

Ito, Takeyasu M., Adamek, E. R., Callahan, N. B., Choi, J. H., Clayton, S. M., Cude-Woods, C., Currie, S., Ding, X., Fellers, D. E., Geltenbort, P., Lamoreaux, S. K., Liu, C. -Y., MacDonald, S., Makela, M., Morris, C. L., Pattie, R. W., Ramsey, John Clinton, Salvat, D. J., Saunders, A., Sharapov, E. I., Sjue, S., Sprow, A. P., Tang, Z., Weaver, H. L., Wei, W., and Young, A. R. Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment. United States: N. p., 2018. Web. doi:10.1103/PhysRevC.97.012501.
Ito, Takeyasu M., Adamek, E. R., Callahan, N. B., Choi, J. H., Clayton, S. M., Cude-Woods, C., Currie, S., Ding, X., Fellers, D. E., Geltenbort, P., Lamoreaux, S. K., Liu, C. -Y., MacDonald, S., Makela, M., Morris, C. L., Pattie, R. W., Ramsey, John Clinton, Salvat, D. J., Saunders, A., Sharapov, E. I., Sjue, S., Sprow, A. P., Tang, Z., Weaver, H. L., Wei, W., & Young, A. R. Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment. United States. doi:10.1103/PhysRevC.97.012501.
Ito, Takeyasu M., Adamek, E. R., Callahan, N. B., Choi, J. H., Clayton, S. M., Cude-Woods, C., Currie, S., Ding, X., Fellers, D. E., Geltenbort, P., Lamoreaux, S. K., Liu, C. -Y., MacDonald, S., Makela, M., Morris, C. L., Pattie, R. W., Ramsey, John Clinton, Salvat, D. J., Saunders, A., Sharapov, E. I., Sjue, S., Sprow, A. P., Tang, Z., Weaver, H. L., Wei, W., and Young, A. R. Mon . "Performance of the upgraded ultracold neutron source at Los Alamos National Laboratory and its implication for a possible neutron electric dipole moment experiment". United States. doi:10.1103/PhysRevC.97.012501. https://www.osti.gov/servlets/purl/1422926.
@article{osti_1422926,
title = {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, Takeyasu M. and Adamek, E. R. and Callahan, N. B. and Choi, J. H. and Clayton, S. M. and Cude-Woods, C. and Currie, S. and Ding, X. and Fellers, D. E. and Geltenbort, P. and Lamoreaux, S. K. and Liu, C. -Y. and MacDonald, S. and Makela, M. and Morris, C. L. and Pattie, R. W. and Ramsey, John Clinton and Salvat, D. J. and Saunders, A. and Sharapov, E. I. and Sjue, S. and Sprow, A. P. and Tang, Z. and Weaver, H. L. and Wei, W. and Young, A. R.},
abstractNote = {We report the ultracold neutron (UCN) source at Los Alamos National Laboratory (LANL), which uses solid deuterium as the UCN converter and is driven by accelerator spallation neutrons, has been successfully operated for over 10 years, providing UCN to various experiments, as the first production UCN source based on the superthermal process. It has recently undergone a major upgrade. This paper describes the design and performance of the upgraded LANL UCN source. Measurements of the cold neutron spectrum and UCN density are presented and compared to Monte Carlo predictions. The source is shown to perform as modeled. The UCN density measured at the exit of the biological shield was 184(32) UCN / cm3, a fourfold increase from the highest previously reported. Finally, the polarized UCN density stored in an external chamber was measured to be 39(7) UCN / cm3, which is sufficient to perform an experiment to search for the nonzero neutron electric dipole moment with a one-standard-deviation sensitivity of σ(dn) = 3 × 10-27 e cm.},
doi = {10.1103/PhysRevC.97.012501},
journal = {Physical Review C},
number = 1,
volume = 97,
place = {United States},
year = {2018},
month = {1}
}

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Figures / Tables:

FIG. 1 FIG. 1: The layout of the LANL UCN facility. Part of the biological shield is removed in this figure to show the UCN source and guides.

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    Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.