Development and evaluation of a Monte Carlo Code System for analysis of ionization chamber responses

Abstract

This document reports on the development and testing of a Monte Carlo code system for calculating the response of an ionization chamber to mixed neutron and photon radiation environment. The code system, Monte Carlo Ionization Chamber Analysis Package (MICAP), determines the neutron, photon, and total responses of the ionization chamber to the mixed field radiation environment. The Monte Carlo method performs accurate simulations of the physical processes involved in detecting radiation using ionization chambers, and eliminates limitations inherent in approximate methods. To evaluate MICAP, comparisons were made with results obtained using other code systems and with experimental results. Separate comparisons with other code systems verified the validity of the neutron, photon, and charged particle transport processes and the nuclear models used to describe the individual neutron reactions, respectively. Comparisons with mono-energetic photon calibration experiments and with mixed neutron and photon radiation experiments verified the applicability of MICAP for analyzing the response of ionization chambers to mixed field radiation environments. 47 refs., 23 figs., 20 tabs.