Year
2011
Abstract
This paper describes a mobile gamma ray measurement system concept, to provide high sensitivity detection and location capability of radionuclides. Some experimental characterization is provided. Because radionuclide distributions may be uncertain and ranging from physically small to large area contamination, gamma ray detector assemblies with differing fields of view are utilized. Important considerations for this approach include the maximizing of detection efficiency while minimizing background interference. Because the detector assemblies utilized are both highly efficient and exhibit directional measurement capability, it is possible to exploit their rejection of unwanted directional radiation and mitigate interfering scatter. Scatter fractions may also be used to help identify the presence of radionuclides. Such measurements are considered over the practical range of standoff distances possible with gamma ray detector systems. System simplicity and associated costs are always a critical consideration and this approach is targeted to minimize equipment cost while maintaining maximum sensing performance. The use of supplemental portable equipment (i.e., Infrared, Laser Induced Breakdown Spectroscopy (LIBS)) in the detection procedure is feasible.