THE MEASUREMENT OF Cf-252 SPONTANEOUS FISSION PROMPT NEUTRON SPECTRUM IN THE LOWER ENERGYInstitute of Heavy Ion Physics, Peking University 100871 Beijing, P.R. China Jiangchen Meng, Anli Li, Zhongyu Bao, Shengnian Huang Institute of Atomic Energy, P.O. Box. 275 Beijing, P.R. China The prompt neutron spectrum from Cf-252 spontaneous fission in the low energy has been measured with TOF method. The neutron detectors were the lithium glasses (with different products and thickness). The fragment detector was a mini-ionization chamber. The intensities of the Cf-252 source were different in different run. The flight paths varied from 30 to 50 cm. The prompt neutron detectors' efficiencies were calculated with Monte Carlo method. The absolute efficiencies of the detectors will be determined by experiment, which will be done in CBNM, Geel, Belgium. The experiment was carried out in a 1960 m3 hall, and the corrections were considered. The preliminary result was given. And the last result will be given after the determination of the neutron detector efficiencies. KEYWORDS: neutron spectrum, Cf-252, lithium glass, ionization chamber, preliminary result |