Commissioning of the NPDGamma Detector Array: Counting Statistics in Current Mode Operation and Parity Violation in the Capture of Cold Neutrons on B 4 C and (27) Al.
The NPDGamma γ-ray detector has been built to measure, with high accuracy, the size of the small parity-violating asymmetry in the angular distribution of gamma rays from the capture of polarized cold neutrons by protons. The high cold neutron flux at the Los Alamos Neutron Scattering Center (LANSCE) spallation neutron source and control of systematic errors require the use of current mode detection with vacuum photodiodes and low-noise solid-state preamplifiers. We show that the detector array operates at counting statistics and that the asymmetries due to B4C and (27)Al are zero to with- in 2 × 10(-6) and 7 × 10(-7), respectively. Boron and aluminum are used throughout the experiment. The results presented here are preliminary.
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
M T
MT
Gericke
Indiana University, Bloomington, Indiana 47405, USA.
J D
JD
Bowman
Thomas Jefferson National Accelerator Facility, Newport News VA 23606, USA.
R D
RD
Carlini
University of Michigan, Ann Arbor, MI 48104, USA.
T E
TE
Chupp
University of Michigan, Ann Arbor, MI 48104, USA.
K P
KP
Coulter
University of New Hampshire, Durham, NH 03824, USA.
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Dabaghyan
University of Tennessee, Knoxville, TN 37996, USA.
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Desai
University of California, Berkeley, CA 94720-7300, USA.
S J
SJ
Freedman
National Institute of Standards and Technology, Gaithersburg, MD 20899-0001, USA.
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TR
Gentile
University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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RC
Gillis
Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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GL
Greene
University of New Hampshire, Durham, NH 03824, USA.
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FW
Hersman
High Energy Accelerator Research Organization (KEK), Tukubash-shi, 305-0801, Japan.
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Ino
High Energy Accelerator Research Organization (KEK), Tukubash-shi, 305-0801, Japan.
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Ishimoto
Hamilton College, Clinton, NY 13323, USA.
G L
GL
Jones
University of California, Berkeley, CA 94720-7300, USA.
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B
Lauss
Indiana University, Bloomington, Indiana 47405, USA.
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MB
Leuschner
Indiana University, Bloomington, Indiana 47405, USA.
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B
Losowski
University of Tennessee, Knoxville, TN 37996, USA.
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R
Mahurin
High Energy Accelerator Research Organization (KEK), Tukubash-shi, 305-0801, Japan.
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Y
Masuda
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
G S
GS
Mitchell
High Energy Accelerator Research Organization (KEK), Tukubash-shi, 305-0801, Japan.
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S
Muto
Indiana University, Bloomington, Indiana 47405, USA.
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H
Nann
University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.
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Page
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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SI
Penttila
TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
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WD
Ramsay
Indiana University, Bloomington, Indiana 47405, USA.
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S
Santra
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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PN
Seo
Joint Institute for Nuclear Research, Dubna, Russia.
E I
EI
Sharapov
University of Dayton, Dayton, OH 45469, USA.
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TB
Smith
Indiana University, Bloomington, Indiana 47405, USA.
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WM
Snow
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
W S
WS
Wilburn
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
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V
Yuan
University of New Hampshire, Durham, NH 03824, USA.
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Zhu
CsI; current mode; detector; gamma; neutron capture; parity violation