HIGH PERFORMANCE, DIRECTIONAL GAMMA RAY DETECTOR SOLUTIONS FOR THE DETECTION AND QUANTIFICATION OF CRITICAL MATERIALS

Year
2009
Author(s)
Steven E. Smith - Oak Ridge National Laboratory
Alexander A. Solodov - Oak Ridge National Laboratory
J. S. Bogard - Oak Ridge National Laboratory
Graham V. Walford - Walford Technologies, Inc.
Abstract
Cost effective creation of a well defined field of view for large gamma ray detectors is typically through the use of large and heavy collimation, often making portable applications impractical. In this work we have overcome this limitation with the use of a multi-plate collimator assembly that can provide “line” or other shaped fields of view with simple and easy manipulation. Of significance is that this collimation approach is highly effective up to 1.5 MeV for a system weight addition of less than 2.5 Kg. Such collimators readily provide 6 degrees (or better) field of view with minimal loss of detection efficiency when measured on the source-detector axis. If necessary, for some portable type applications, once an elevated exposure level had been observed, this collimation assembly may be field installed to help target unidentified source material locations. In this work several measurement examples are discussed.