Accession Number:

ADA413884

Title:

Detection of Special Nuclear Material with High Purity Germanium (HPGe) and Mercuric Iodide (HgI2) Gamma Detectors

Descriptive Note:

Master's thesis Jun 2002-Mar 2003

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT

Personal Author(s):

Report Date:

2003-03-01

Pagination or Media Count:

126.0

Abstract:

The Defense Threat Reduction Agency DTRA contracted for two gamma radiation detectors mercuric iodide HgI2 and electromechanically cooled EMC high purity germanium HPGe to support arms control inspection efforts. This project investigated whether these detectors could measure the quality and quantity of special nuclear material SNM, particularly Pu-239 for the treaty verification mission. The project investigated two areas of detector capabilities 1 HgI2 and HPGe detector performance necessary to characterize the quality of plutonium and the presence of shielding materials and 2 HgI2 and EMC HPGe detector performance degradation by high noise levels and EMC HPGe detector performance degradation caused by electromechanical-cooling. The first area studied the response functions of each of the detectors necessary to meet the detection objectives measure the Pu-239Pu 240 ratio to identify weapons grade plutonium and to identify a phony weapon. The second area of detector performance evaluated was the EMC HPGe detectors cooling capabilities and its effect on the performance of the detector. The results show that neither of the detectors was ideally capable of supporting DTRAs requirements. The HgI2 detector did not have sufficient efficiency or resolution to distinguish between Weapon Grade and Reactor Grade Plutonium. The EMC system suffered from grounding problems that degraded the resolution and efficiency. An initial study, evaluating the ability of detectors to determine the presence of a simulated tamper within the SNM physics package, showed great promise for identifying phony weapons.

Subject Categories:

  • Electromagnetic Shielding

Distribution Statement:

APPROVED FOR PUBLIC RELEASE