On the use of averaging stopping power of recoiled nuclei for determining maximum neutron energy of 241Am–Be by superheated drop detectors

Abstract

The average stopping power of the recoiled nuclei generated by neutron elastic interactions with the Freon-12 drops in a superheated drop detector has been used to determine the maximum neutron energy of the 241Am–Be source. In an elastic interaction of neutrons with the Freon-12 liquid, the nuclei of 12C, 19F and 35Cl with different values of stopping power are scattered. The stopping power of these scattered nuclei corresponding to the energy transferred to them through the head-on collision was extracted from the SRIM code. The stopping power values were weighted by considering the neutron–nucleus elastic scattering cross section and the number of each nucleus in the Freon-12 molecule and the average stopping power was calculated from known neutron energy.The maximum energy of the 241Am–Be neutron source was estimated as 10.9 ± 3.0 MeV. The consistency between the determined energy and the other reported values confirms the validity of using the average stopping power in the superheated drop detectors. The average stopping power was also used to determine the threshold neutron energy as a function of external applied pressure at different temperatures. Knowing the threshold neutron energy as function of applied pressure, can be used in pressure scanning method for neutron spectrometry by superheated drop detectors.