Measurement and analysis of fission rates in depleted uranium and depleted uranium–polyethylene shells with neutrons from D-T reaction

Note: Calibration of majority isotopes for enriched and depleted uranium fission chambers by using the elimination method with fast neutrons

Calibrated miniature pulse fission chambers (MPFCs) can be used for absolute measurement of the fission reaction rate in neutronic experiments. Absolute measurements require the effective number of fissionable atoms (ENFAs) in the coating of the chambers. An elimination method was proposed to calibrate the MPFCs embodying highly enriched and depleted uranium, using 14.75 MeV fast neutrons from the D-T reaction. The ENFAs of ²³⁵U in enriched uranium MPFC and ²³⁸U in depleted uranium MPFC are 8.39 × 10¹⁸ and 9.55 × 10¹⁸, with the uncertainties of 5.27% and 4.76%, respectively.