Development of the Monte Carlo-library least-squares method of analysis for neutron capture prompt gamma ray analyzers.

摘要

A new analysis principle called the Monte Carlo-Library Least-Squares (MCLLS) principle has been identified and investigated in a preliminary way for neutron capture prompt gamma-ray(NCPGR) analyzers. This method consists of: (1) generating the complete gamma-ray spectral response for a sample of known (assumed) composition by Monte Carlo simulation, (2) keeping track of the individual elemental responses within the Monte Carlo simulation for use as library spectra, (3) use of the (linear) library least-squares analysis method to obtain the elemental concentrations for any unknown sample spectrum, and (4) iterating these steps if the unknown concentrations are too far from the assumed composition originally used.;In order to apply the MCLLS method to obtain sample elemental concentrations, the elemental library spectra of the sample elements are required. To accomplish this, an existing Monte Carlo model which simulates the analysis of coal on a conveyor belt using ;By studying with the simulated spectra, the MCLLS method appears to be feasible for a good initial guess of the sample composition; furthermore, the proposed iterative MCLLS algorithm works for poor initial guesses of the major element amounts. Testing of the proposed algorithm on the experimental spectrum showed that for the practical application of the iterative MCLLS method certain guidelines should be used. These are provided in the dissertation. The major problems with the application of MCLLS and their possible solutions are also discussed.