PROPERTIES OF THRESHOLD DETECTORS FOR TESTING NEUTRON DOSIMETRY CALIBRATIONS

A neutron detector combination based on solid state nuclear track dete ctors, which makes use 0 uranium oxide and LiF converters together wit h cadmium and plastic absorbers was calibrated in a known neutron fiel d of a heavy water moderated Cf-252 source. From the derived equations describing the spectrometer characteristics it is possible to measure the average U-235 neutron fission cross section sigma(I)5BAR in the e nergy interval from 10 to 10(4) eV where there are more than 50 resona nces. Sigma(I)5BAR was obtained from fission track densities in two Ma krofol detectors, a bare one and one with cadmium shielding. The exper imental sigma(I)5BAR values of 5.7 and 20.5 b agree with the calculate d values of 1.3 to 22 b obtained from a nuclear data code. The reporte d average cross section values cannot be considered as new nuclear dat a, but the utility is shown of using them for data analysis.