Portable LN2 gamma-ray spectrometer system

The purpose of this program is to design and demonstrate a highly sensitive , portable spectrometer for detecting and identifying trace amounts of nucl ear materials in a broad range of nonproliferation scenarios. A high-effici ency 100% n-type germanium (Ge) detector is combined with a special liquid nitrogen dewar designed to accommodate an active Compton suppression shield . The added collimation capability is required in order to be able to ident ify localized sources that may be obscured by background radiation. These c omponents are complemented by the addition of a newly developed state-of-th e-art multichannel analyzer (MCA) capable of 64 x 16 000 channel acquisitio n and electronic Compton suppression. The entire system fits into a waterti ght case that could be stored below the seat of commercial airliners. The u nit has 2.74 keV resolution at 1.33 MeV, 8.5 degrees angular resolution, lo w-power, > 25 h full-time battery life, and operations between 35 keV < E < 3 MeV. (C) 1999 Published by Elsevier Science B.V. All rights reserved.