## A Monte Carlo Approach to Calculate Probability Tables for the Unresolved-Resonance Region Using the AMPX Cross-Section Processing System

A new module, PURM (Probability tables for the Unresolved Region using Monte Carlo), has been developed for the AMPX-2000 cross-section processing system. PURM uses a Monte Carlo approach to calculate probability tables on an evaluator-defined energy grid in the unresolved-resonance region. For each probability table, PURM samples a Wigner spacing distribution for pairs of resonances surrounding the reference energy. The resonance distribution is sampled for each spin sequence (i.e., {ell}-J pair), and PURM uses the {Delta}{sub 3}-statistics test to determine the number of resonances to sample for each spin sequence. For each resonance, PURM samples the resonance widths from amore »