#### College - Author 1

College of Science and Mathematics

#### Department - Author 1

Physics Department

#### Degree Name - Author 1

BS in Physics

#### Date

6-2023

#### Primary Advisor

Tom Bensky, College of Science and Mathematics, Physics Department

#### Abstract/Summary

Gamma rays principally interact with matter through Compton scattering, photoelectric effect, pair production, and triplet production. The focus of this simulation is to study the theoretical energy spectrum created by gamma rays from a Cesium-137 source, which produces gamma photons with an energy of 0.662 MeV. At this energy level, most interactions are results of Compton scatters and the photoelectric effect. Therefore, this simulation only models those two effects on gamma rays. Using Monte Carlo methods and the Metropolis algorithm to sample the probability distributions of the two effects allowed for the simulation of gamma rays in a Sodium Iodide detector. Using these methods produced a theoretical spectrum for Cesium-137 that closely matches those from other simulations, as well as an actual spectrum. The spectrum lacks certain features, such as a backscatter peak and the energy smearing that is seen in an actual spectrum, but it does model the Compton shelf and the principal photopeak. This allows for accurate modeling of different size detectors and gamma rays under one MeV.

**URL:** https://digitalcommons.calpoly.edu/physsp/224