PNNL

Abstract

When processing the results of neutron measurements it is useful in some cases to be able to assess the value of the alpha parameter (ratio of neutron production rate due to (alpha, n) reaction to that due to spontaneous fission) in a sample. The application was developed for the express evaluation of the parameter for plutonium-bearing materials based on the isotopic composition of plutonium and the elemental content of compound. The application exploits a traditional approach using Ziegler’s coefficients to calculate alpha particle stopping powers. However, the application uses weight values instead of atomic ones as input data of elemental content that in turn allows easily evaluate the parameter for any material (both pure “theoretical” compound and real one containing various impurities). A practical advantage is that a user needs to know weight content of elements (as a normal practice) and not chemical formulae for all components of a compound. Some results of comparison between the Alpha Parameter application and the well known code Sources4A are presented. The application was verified and validated by PNNL for its usage in NDA project. Alpha parameter is freeware and available on request from authors.