Report on the performance of a large-area, gamma-ray imager for search
We are currently constructing a prototype, large-area, gamma-ray detector for conducting vehicle-mounted, mobile-search operations. The system is unique in that it relies on imaging to discriminate point sources of interest from the natural background variations. In a non-imaging instrument the background fluctuations mimic the signature seen from real sources at a distance and one is limited in sensitivity to detecting only those sources that overwhelm the local background variations --not just the counting statistics associated with a given measurement. The net result is that a larger detector is generally not more sensitive to detecting sources in the world at large. [1, 2] In a previous publication [3] we reported on the detection of a 1-mCi source at more than 80 meters from the detector using a proof-of-principle instrument (see Fig. 1) constructed to demonstrate how imaging removes the size limit on search instruments. In this report we document a systematic effort using the same detector to demonstrate that imaging detectors can reliably detect weak radiation sources at many 10's of meters. Specifically, we collected data on a 1-mCi {sup 137}Cs source 65 m from the path of the search instrument.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 885378
- Report Number(s):
- UCRL-TR-216328; TRN: US0603878
- Country of Publication:
- United States
- Language:
- English
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