PRODUCT YIELDS OF 232Th PHOTO-FISSION INDUCED BY MONOCHROMATIC GAMMA RAYSInstitute of Atomic Energy P.O. Box 275-46, Beijing, China 13 cummulative yields and 10 mass chain yields from 87Kr to 143Ce were determined absolutely for fission of 232Th induced by 7.64 MeV monochromatic gamma rays. The gamma photons were obtained from the thermal neutron capture gamma source installed at the swimming pool reactor of IAE, by using Fe radiator. The samples used were Th metal disks which were sandwiched between two thin Th foils during irradiation. The fission events of these thin Th foils were detected by solid state nuclear track detectors. In this way the fission rate was determined absolutely. The influence of fast neutrons was investigated and corrected accordingly. Fission product activities of irradiated samples were measured by Ge(Li) gamma ray spectrometry. KEYWORDS: Fission yields, photo-fission, 232Th, thermal neutron capture gamma rays |