Computer-Based Investigative Techniques: A Comparison of Dose Using the MCNP Code for Optically Stimulated Light Dosimeters

A computer-based investigative technique, using the Los Alamos Monte Carlo code MCNP5 version 1.51 (Radiation Safety Information Computational Center), was completed to assess the shallow dose equivalent (SDE) reported on the Landauer, Inc.,^TM Luxel+ optically stimulated light (OSL) dosimeter. Experimental test irradiations were conducted on 18 OSL dosimeters through various controlled exposures to the source (10 mCi ⁹⁰Sr). The reported SDE for each test irradiation was compared to the results for SDE calculated using MCNP5. All test irradiation experiments were conducted with the ⁹⁰Sr source placed in direct contact with the dosimeter with slight placement changes across the dosimeter face. It was found that these slight adjustments caused vast differences in reported doses by Landauer. The SDE determined in a tissue matrix using MCNP5 was studied for two of the dosimeter badge geometries, and it was found that some qualitative agreement exists between the reported and simulated doses in contradiction with the experimental results. Further simulated analysis was not conducted because precise source-dosimeter geometries and the algorithm used by Landauer to analyze its Luxel+ OSL dosimeters were not known. These results indicate that a future study should be conducted with more rigorous simulated benchmarking to verify these results.