Characterization and Comparison of New Concepts in Neutron Detection

1. Characterization and Comparison of New Concepts in Neutron Detection MIDN 2/C Kayla J. Sax Advisers: Professor Martin E. Nelson – Mechanical Engineering Professor Svetlana Avramov-Zamurovic – Systems Engineering CAPT Charles B. Cameron – Electrical Engineering Professor James F. Ziegler – Physics

2. Overview • Objective • Related Work and Support • Background • Method • Analysis • Applications • Contribution • Questions

3. Objective • Premise • Objective: Evaluate both unmodified and modified memory chips for sensitivity to neutrons, comparing them to conventional detection systems, in an effort to establish their potential for general scientific use.

4. Naval Research Laboratory: Related Work and Support • Naval Research Laboratory (NRL) • Point of contact: Dr. Harold Hughes, Solid State Devices Branch • Developing device to be utilized for remote detection of nuclear weapons of mass destruction (WMDs). • Supporting and funding project.

5. Neutron Detection System Applications • Hospitals and Health physics • Nuclear power plants • International nuclear weapons treaty compliance • Homeland security • Military

6. Lithium Fluoride Crystals Conventional Neutron Detection Systems • Non-powered • Thermoluminescent dosimeter (TLD) • Foil activation detector • Bubble detector • Track-etch detector • Powered • BF3 proportional counter • 3He proportional counter

7. Conventional Neutron Detection Systems Non-powered Thermoluminescent dosimeter (TLD) Foil activation detector Bubble detector Track-etch detector Powered BF3 proportional counter 3He proportional counter

8. Conventional Neutron Detection Systems Non-powered Thermoluminescent dosimeter (TLD) Foil activation detector Bubble detector Track-etch detector Powered BF3 proportional counter 3He proportional counter

9. Conventional Neutron Detection Systems Non-powered Thermoluminescent dosimeter (TLD) Foil activation detector Bubble detector Track-etch detector Powered BF3 proportional counter 3He proportional counter

10. Conventional Neutron Detection Systems Non-powered Thermoluminescent dosimeter (TLD) Foil activation detector Bubble detector Track-etch detector Powered BF3 proportional counter 3He proportional counter

11. Conventional Neutron Detection Systems:Advantages and Disadvantages • Non-powered • Advantages: • Require no external energy source and therefore can operate in almost any environment. • Relatively inexpensive compared to more complicated powered detectors. • Disadvantages: • Passive; provide the user no instantaneous information. • Powered • Advantages: • Active; provide information on radiation exposure more quickly and more often. • Disadvantages: • Require a significant amount of power, operating at 900V – 1500V.

12. Detection Methods Based on Integrated Circuit Components • Conventional detection systems that rely on integrated circuit components: • Direct Ion Storage (DIS) Dosimeter • Metal Oxide Semiconductor Field Effect Transistor (MOSFET) Dosimeter • No neutron detection system relying on memory cells is currently competitive with other detectors.

13. Utilizing Static Random Access Memory (SRAM) for Neutron Detection • Metric: Soft Error Rate (SER) • Theory: Technological advances and their result on SER trends. • Result: An SRAM chip with a high SER makes an inferior memory device but an excellent neutron detector.

14. Unmodified Chip Typical Unmodified Memory Chip Dimensions (Cross-Section)

15. Sensitivity-Enhancing Modification of Chips Modified Memory Chip (Cross-Section)

16. Sensitivity-Enhancing Modification of Chips Modified Memory Chip (Isometric View)

17. Method for Evaluation of SRAM Sensitivity

18. Summary of Experimental Plan

19. Summary of Experimental Plan

20. Summary of Experimental Plan

21. Pu-Be Source USNA D-D Neutron Generator USNA D-T Neutron Generator in Exposure Room USNA Sub-Critical Reactor Neutron Sources Available at USNA

22. Summary of Experimental Plan

23. Analysis • Sensitivity of each detection system to a particular incident neutron energy established. • Confidence level for each sensitivity determined. • Minimum dose sensitivity and dose saturation level established.

24. Special Application: Screening Cargo Containers for WMDs • NRL scheduled to produce three additional devices. • Pending successful production, NRL has asked to collaborate with me to extend my research into evaluating the group of new devices. • Expansion of work into developing a new system of nuclear WMD monitors for cargo containers.

25. Timeline • 2/C Spring Semester • Take Reactor Physics I (EM362) • Conduct additional background research • 1/C Summer • Participate in University of Florida Internship • Order bubble detectors and track-etch detectors • Obtain unmodified/modified chips and tester from NRL • 1/C Fall Semester • Ensure operational status of detection systems • Cross-calibrate TLD, bubble, and track-etch detectors against foil activation with 14 MeV source • Test, analyze, and evaluate all detectors with 14 MeV source • Write interim report • 1/C Spring Semester • Test, analyze, and evaluate all detectors with remaining sources • Conduct complete comparative analysis • Write and present final Trident Scholar report • Present final results at a technical conference

26. Contribution • Characterization of a brand new concept in neutron detection. • Establish the potential for detection system to improve existing applications. • Establish the potential for detection system to be implemented as a remote special nuclear material detection system in cargo containers.

27. Characterization and Comparison of New Concepts in Neutron Detection Advisers: Professor Martin E. Nelson – Mechanical Engineering Professor Svetlana Avramov-Zamurovic – Systems Engineering CAPT Charles B. Cameron – Electrical Engineering Professor James F. Ziegler – Physics MIDN 2/C Kayla J. Sax