Developments in High-Performance HPGe Detector Spectrometer Systems for Safeguards Applications

Both fixed and portable safeguards applications place stringent demands on spectrometer systems. Instruments must perform well spectroscopically despite operation in harsh environments. Resolution and stability requirements for Pu isotopic systems hardware are based on the complexity of the spectrum and the necessity for the analysis software codes to use multipeak regions of the spectrum. Better detector resolution and more stable peak shape/position results in improved precision. Higher throughput is an advantage only if the system remains stable across the count-rate range. If this is achieved, usability is enhanced because of reduced count times, increased sample throughput, and less operator exposure. Choice of software platform is important for: 1) ease of operation, 2) the availability of common tools (spreadsheets, word processors, tool-kits) for application developers, and 3) availability of low-cost PC hardware. Data communication to the PC should be convenient, fast, and reliable, via industry-standard hardware. PORTABLE instrument practicality is further enhanced by factors such as small size, light weight, and long battery life. Two new instruments, one portable and one mains-powered for fixed installations, are described. Both use a common Windows 95/Windows NT software platform. The portable instrument matches the best analog spectrometers in performance, weighs under 5.25 lbs, and operates for over 7 hours without changing batteries. The mains-powered unit is DSP-based, featuring extensive setup automation and greatly improved stability over previous analog designs. Performance data are presented.