Parity nonconservation in neutron resonances in {sup 232}Th

Journal Article · Sat Aug 01 00:00:00 EDT 1998 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.58.1236· OSTI ID:639198

Stephenson, S L; Lowie, L Y; Mitchell, G E ^[1]; Bowman, J D; Frankle, C M; Knudson, J N; Penttilae, S I; Seestrom, S J; Yen, Y; Yuan, V W ^[2]; Crawford, B E; Roberson, N R ^[3]; Delheij, P P ^[4]; Iinuma, M; Masaike, A; Matsuda, Y ^[5]; Postma, H ^[6]; Sharapov, E I ^[7]

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1. North Carolina State University, Raleigh, North Carolina 27695-8202 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 (United States)
2. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
3. Duke University, Durham, North Carolina 27708 and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 (United States)
4. TRIUMF, Vancouver, British Columbia, V6T 2A3 (CANADA)
5. Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)
6. University of Technology, Delft, 2600 GA (The Netherlands)
7. Joint Institute for Nuclear Research, 141980 Dubna (Russia)

Parity nonconservation (PNC) was measured for 24 p-wave resonances from 8 to 300 eV in {sup 232}Th by measuring the helicity dependence of the total neutron cross section for epithermal neutrons with an improved experimental system. Ten resonances show statistically significant parity violation. For these ten resonances the analyzing powers are all positive, thus confirming the previously observed sign correlation. The data are fit to the sum of two terms, a constant asymmetry and a fluctuating asymmetry. With this ansatz the root-mean-square PNC matrix element M=1.12 meV, which corresponds to a weak spreading width {Gamma}{sub w}=4.7{times}10{sup {minus}7} eV. For the neighboring nuclide {sup 238}U there is no constant offset, suggesting that the sign correlation is specific to {sup 232}Th. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 639198
• Journal Information: Physical Review, C, Vol. 58, Issue 2; Other Information: PBD: Aug 1998
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
RESONANCE NEUTRONS
THORIUM 232
PARITY
P WAVES
HELICITY
TOTAL CROSS SECTIONS
FLUCTUATIONS
URANIUM 238
CORRELATIONS
NEUTRON REACTIONS