PULSE HEIGHT TALLY RESPONSE EXPANSION METHOD FOR APPLICATION IN DETECTOR PROBLEMS

A new incident flux response expansion method (IFLEX) is developed to perform on-the-fly detector pulse height spectra calculations with Monte Carlo accuracy. Given the flux incident on the detector window, the method uses pre-computed continuous energy Monte Carlo based response functions to generate the pulse height tallies. B-spline functions are selected for the expansion of the incident flux in the energy phase space. Response functions are generated for a CsI(Na) crystal using an energy dependent B-spline form of the IFLEX method. The method is verified for two incident flux spectra on the crystal. Results of the energy dependent B-spline form of the method are compared to the solutions generated using the direct Monte Carlo code MCNP5. The method is shown to be several orders faster than MCNP5 while maintaining paralleled accuracy.