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Neutron cross sections of thorium-232

Journal Article · · Nucl. Sci. Eng.; (United States)
OSTI ID:5404952

The cross sections for neutron interactions with thorium targets were measured at several energies. Capture cross sections at 0.0253 eV and at 2 and 23.4 keV were measured by activation techniques. Transmission measurements were made from 10 to 100 eV, and capture cross sections were determined from 0.03 to 15 eV by recording discrete lines for the (n,..gamma..) spectrum. The measured thermal cross section is 7.41 +- 0.08 b, at 2 keV the cross section is 1.96 +- 0.10 b, and at 24.3 keV it is 0.540 +- 0.014 b. These values are reported relative to an assumed /sup 231/Pa branching ratio of 38.5% for the 311-keV gamma ray, and they do not include the branching ratio error. The results are fitted to R-matrix parameters. The transmission and (n,..gamma..) measurements lead to parameters that give a somewhat higher epithermal capture than previously expected in thorium. This result brings the differential data into better agreement with experiments on subcritical assemblies.

Research Organization:
Brookhaven National Lab., Upton, NY
OSTI ID:
5404952
Journal Information:
Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 72:2; ISSN NSENA
Country of Publication:
United States
Language:
English