skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Interim report on the ORNL absolute measureoffoments of anti. nu. /sub p/ for /sup 252/Cf

Technical Report ·
DOI:https://doi.org/10.2172/5938627· OSTI ID:5938627

An initial effort was made to measure absolutely the average number of prompt neutrons, anti ..nu../sub p/, emitted in spontaneous fission of /sup 252/Cf to an unprecedented accuracy of +- 0.25%. Fission neutrons were counted with a large, gadolinium poisoned, liquid scintillator. A white source of neutrons from the ORELA was used to calibrate the detector efficiency as a function of neutron energy. Source neutrons were scattered into the large scintillator by a thin NE-213 proton-recoil detector which employed pulse shape discrimination to eliminate unwanted ..gamma..-ray background. The resulting neutron-energy and scattering angle-dependent efficiencies were used to normalize a Monte Carlo calculation of the scintillator efficiency for fission neutrons. Under the assumptions that the effects of parasitic charged particle reactions and multiple neutron scattering in the proton-recoil counter have negligible influence on the efficiency calibration, the value of the average number of prompt neutrons emitted per /sup 252/Cf fission was found to be 3.783 +- 0.010. This report is intended as a documentary and guide for future measurements incorporating improvements suggested by the analysis of this first determination. 31 references.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
5938627
Report Number(s):
ORNL/TM-6805; TRN: 79-020516
Country of Publication:
United States
Language:
English