Shielding Algorithm System (SAS) Software for the Analysis of Gamma Ray Spectra


  1. Moats, K.
Corporate Authors
Defence Research and Development Canada, Ottawa Research Centre, Ottawa ON (CAN);Zernam Enterprises Inc., Ottawa ON (CAN)
The objective of the Special Nuclear Material (SNM) detection work being conducted at Defence Research and Development Canada (DRDC) is to develop technologies that improve the ability of the Canadian Armed Forces (CAF) to detect, quantify, and determine the threat level of SNM. The Shielding Algorithm System (SAS) software is one such tool, which uses an improved analysis of gamma ray spectra from radiological sources or SNM to determine the quantity and threat level of the material. The existing SAS C++ software was modified, and an improved algorithm was implemented to calculate the shielding factor for several combinations of shielding materials, including self-shielding effects. This algorithm uses a chi-squared minimization routine based on the Minuit code, and was tested using a Ra-226 source shielded with 2 inches of lead, as well as a Pu-239 source of unknown configuration to test the self-shielding calculations. Using the spectrum generated, the activity of the source was determined by the algorithm and found to agree with the expected values in each case. The best-fit materials and thicknesses determined by the program were also found to be as expected. This software tool has demonstrated that an improved estimate of the activity and shielding materials of shielded isotopes is achievable in these relatively simple cases. Further testing of more complicated spectra is underway to implement additional features in the code, and to improve the calculations and user int
radiation detection;special nuclear material;identification;isotope enrichment;gamma-ray;spectrometry;radiation shielding
Report Number
DRDC-RDDC-2017-C101 — Contract Report
Date of publication
01 May 2017
Number of Pages
Electronic Document(PDF)

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