The 2004 NPDGamma Commissioning Run-Measurement of Parity-Violating Gamma-Ray Asymmetries in Neutron Capture on Al, Cu, Cl, In, and B

Journal Article · Tue May 24 04:00:00 EDT 2005 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.1945104· OSTI ID:20722657

Seo, P -N; Bowman, J D; Mitchell, G S; Penttilae, S I; Wilburn, W S; Yuan, V ^[1]; Carlini, R D ^[2]; Chupp, T E; Coulter, K P ^[3]; Dabaghyan, M; Hersman, F W; Zhu, H ^[4]; Dawkins, M; Leuschner, M B; Lozowski, B; Nann, H; Santra, S; Snow, W M ^[5]; Desai, D; Mahurin, R ^[6]

---

1. Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2. Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)
3. Department of Physics, University of Michigan, Ann Arbor, MI 48104 (United States)
4. Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)
5. Department of Physics, Indiana University, Bloomington, IN 47405 (United States)
6. Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); and others

The NPDGamma experiment will measure with a high precision, 5x10-9, the small parity-violating gamma-ray asymmetry, A{gamma}, in polarized cold neutron capture in a para-hydrogen target to determine unambiguously the weak pion-nucleon coupling constant H{sub {pi}}{sup 1}. For the experiment the collaboration has built a new high-flux pulsed cold neutron beam line at LANSCE. In 2004, we first commissioned the beam line and then the apparatus with exception of the hydrogen target. The sensitivity of the apparatus was tested by measuring A{gamma} on Al, B, Cl, Cu, and In. The Cl has a well-known large parity-violating gamma-ray asymmetry that was used to verify the performance of the apparatus. The other nuclei that were studied during the commissioning run are present in materials used for construction of the experiment and are, therefore, possible sources of the false asymmetries since backgrounds are expected to be about 10% of the signal from the neutron capture on hydrogen. We measured A{gamma}{approx_equal}0 for these nuclei except for Cl. We report the status of the experiment and preliminary results of the 2004 commissioning run.

• OSTI ID: 20722657
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 769; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALUMINIUM
ASYMMETRY
BORON
CAPTURE
CHLORINE
COLD NEUTRONS
COPPER
GAMMA RADIATION
HYDROGEN
INDIUM
NEUTRON REACTIONS
PARITY
PERFORMANCE
PION-NUCLEON INTERACTIONS
SENSITIVITY