GAMMA RAY ATTENUATION OF THE M2/M3

A Thesis Presented to The Academic Faculty

by

Desirée R. Prince

In Partial Fulfillment Of the Requirements for the Degree Master of Science in Nuclear and Radiological Engineering in the Woodruff School of Mechanical Engineering

Georgia Institute of Technology

May 2018

COPYRIGHT © 2018 BY DESIRÉE R. PRINCE GAMMA RAY ATTENUATION OF THE M2/M3 BRADLEY FIGHTING VEHICLE

Approved by:

Dr. Nolan E. Hertel, Advisor The Woodruff School of Mechanical Engineering Georgia Institute of Technology

Dr. Steven Biegalski The Woodruff School of Mechanical Engineering Georgia Institute of Technology

Dr. Paul A. Charp The Woodruff School of Mechanical Engineering Georgia Institute of Technology

Date Approved: April 23, 2018

To my mom, Tina, and my sister and brother, Talia and Shawn. There simply are not

enough words to say what you mean to me, but in a word, “everything.”

ACKNOWLEDGEMENTS

First and foremost, I want to thank my Lord and Savior, Jesus Christ. Through

Him, all things are possible.

Next, I would like to thank my advisor, Dr. Nolan Hertel, for taking me on as his student. Certainly, his support, guidance, and knowledge have made all the difference. I would also like to thank my committee members, Dr. Steven Biegalski and Dr. Paul

Charp, for their support in working through even the most unusual of circumstances.

I would like to say a special thanks to Dr. C-K Chris Wang and Dr. Farzad

Rahnema for their willigness to answer my questions and provide additional guidance on how to proceed on the project.

Many thanks to Dr. Michael Shannon and his team at the Georgia Tech Research

Institute (GTRI) for allowing me to work on this project, and a debt of gratitute to my fellow students John Stooksbury, Caleigh Samuels, and Chad Burns, whose contributions have been invaluable.

Finally, thanks to Nicholas Antonio. As my colleauge, confidant, and “battle buddy,” his support has been indispensible.

iv TABLE OF CONTENTS

ACKNOWLEDGEMENTS iv

LIST OF TABLES vii

LIST OF FIGURES ix

LIST OF SYMBOLS AND ABBREVIATIONS xi

SUMMARY xiii

CHAPTER 1. Introduction 1

CHAPTER 2. Theory and Background 4 2.1 The Linear Attenuation Coefficient 4 2.2 The M2/M3 BFV 5 2.3 The AN/VDR-2 and the 60Co, 137Cs, and 226Ra Sources 9 2.4 The MCNP Transport Code for Computational Modeling 11

CHAPTER 3. Experimental Methodology and Procedures 13

CHAPTER 4. Experimental Data Analysis and Results 16 4.1 The Net Absorbed Dose Rate 16 4.2 Calculating the Experimental Dose Attenuation Coefficient 25 4.3 Calculating the Analytical Dose Attenuation Coefficient 27 4.4 Improvements to the Experiment Design 32 4.4.1 Detector and Source Selection 32 4.4.2 Procedural Considerations 34 4.4.3 Experiment Design Considerations 36

CHAPTER 5. Computational Methodology and Procedures 40

CHAPTER 6. Computational Data Analysis and Results 43 6.1 The Absorbed Dose Rate 43 6.2 Calculating the Computational Dose Attenuation Coefficient 51 6.3 A Comparison of the Experimental, Analytical, and Computational Dose Attenuation Coefficients 53 6.4 Protection Factor 58 6.5 Improvements to the Model 60 6.6 Detector Response in the Simulated Radiation Field 61

CHAPTER 7. Conclusion 63

APPENDIX A. MCNP Input for the Cobalt-60 Source at Position A2 with the AN/VDR-2 Internally Installed 65

v APPENDIX B. MCNP Source Definitions for Sources Positioned around the M2/M3 BFV 71

APPENDIX C. MCNP Input for the Cobalt-60 Simulated Radiation Field with the AN/VDR-2 Internally Installed 74

APPENDIX D. MCNP Source Definitions for the Simulated Radiation Field 80

APPENDIX E. A Revised Comparison of the Experimental, Analytical, and Computational Dose Attenuation Coefficients 81

REFERENCES 85