Parity Violation in 232Th Neutron Resonances Above 250 eV

Authors

E I. Sharapov, Joint Institute for Nuclear ResearchFollow
J D. Bowman, Los Alamos National LaboratoryFollow
Bret E. Crawford, Gettysburg CollegeFollow
P P J. Delheij, TRIUMFFollow
C M. Frankle, Los Alamos National LaboratoryFollow
M IInuma, Kyoto UniversityFollow
J N. Knudsen, Los Alamos National LaboratoryFollow
L Y. Lowie, North Carolina State UniversityFollow
J E. Lynch, Gettysburg College
A Masaike, Kyoto UniversityFollow
Y Matsuda, Kyoto UniversityFollow
G E. Mitchell, North Carolina State UniversityFollow
S I. Penttila, Los Alamos National LaboratoryFollow
H Postma, Delft University of TechnologyFollow
N R. Roberson, Duke UniversityFollow
S J. Seestrom, Los Alamos National LaboratoryFollow
Sharon L. Stephenson, Gettysburg CollegeFollow
Y-F Yen, Los Alamos National LaboratoryFollow
V W. Yuan, Los Alamos National LaboratoryFollow

Document Type

Article

Publication Date

1-18-2000

Department 1

Physics

Abstract

The analysis of parity nonconservation (PNC) measurements performed on ²³²Th by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar analysis was performed on the data below 250 eV, for which longitudinal asymmetries were obtained previously. For energies below 250 eV, the p-wave neutron strength functions for the J=1/2 and J=3/2 states were extracted: S_1/2¹=(1.68±0.61)×10^-4 and S_3/2¹=(0.75±0.18)×10^-4. The data provide constraints on the properties of local doorway states proposed to explain the PNC sign effect in thorium.

Copyright Note

This is the publisher's version of the work. This publication appears in Gettysburg College's institutional repository by permission of the copyright owner for personal use, not for redistribution.

Recommended Citation

Sharapov, E.I., et al. Parity violation in 232Th neutron resonances above 250 eV. Physical Review C (2000). 61: 1-7. http://dx.doi.org/10.1103/PhysRevC.61.025501

Required Publisher's Statement

Copyright held by American Physical Society. First published as EI Sharapov et al, Parity violation in 232Th neutron resonances above 250 eV, Physical Review C, 61, 025501, doi: 10.1103/PhysRevC.61.025501.