Kerma Factors of Oxygen, Aluminium, and Silicon for 15 to 20 MeV Neutrons

Abstract

Abstract The previously reported measurements of the kerma factor of carbon have been extended to O, Al, and Si. Cylindrical proportional counters were constructed with walls of Zr, ZrO, Al, and Si. Charged particles produced in the walls deposited energy in the low pressure filling gas. The resulting microdosimetric spectra yielded kerma values. The kerma for O was obtained from the difference between spectra obtained with the ZrO and Zr counters. A similar counter constructed of A-150 tissue-equivalent plastic and an A-150 walled ionisation chamber served to determine the neutron fluence. 15 MeV neutrons were produced with the Lawrence Livermore National Laboratory Rotating Target Neutron Source. 17 to 19 MeV neutrons were obtained by bombarding a tritium gas target with deuterons from the University of Wisconsin electrostatic accelerator.