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U.S. Department of Energy
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THE (n,2n) CROSS-SECTION OF Th$sup 232$ FOR FISSION NEUTRONS

Technical Report ·
OSTI ID:4307615
The mean value of the (n,2n) cross section of Th/sup 232/ for neutrons from U/sup 235/ fission has been determined. Decigram quantities of thorium nitrate were irradiated inside a hollow fuel element in the BEPO reactor. The Th/ sup 233/ formed was allowed to decay into Pa/sup 233/, which was then chemically separated from the thorium together with the fission products. Thc quantity of Th/sup 231/ produced was found by measuring the intensity of the 25.6 kev gamma ray coming from the decay of this isotope using a krypton filled proportional counter. A U/sup 235/ fission foil was used for the intensify calibration of the counter. Animonium sulfate was used as a flux monitor, the activity of the P/sup 32/ from the threshold reaction S/sup 32/ (n,p)P/sup 32/ giving tbe flux. A value of 12.4 plus or minus 0.6 millibarns was obtained for the mean value of the (n,2n) cross section of Th/sup 232/ in a fission spectrum. (auth)
Research Organization:
United Kingdom Atomic Energy Authority. Research Group. Atomic Energy Research Establishment, Harwell, Berks, England
NSA Number:
NSA-12-006221
OSTI ID:
4307615
Report Number(s):
AERE-R/R-2366
Country of Publication:
United Kingdom
Language:
English