Testing of Mechanically Cooled HPGe Detectors to Determine Composition of U and Pu

Liquid nitrogen cooled high purity germanium (HPGe) detectors with planar configuration have been used for decades to accurately determine uranium and plutonium isotopic composition for safeguards and other purposes. Mechanically cooled HPGe detectors have been shown to have similar performance as liquid nitrogen cooled systems except for low energy resolution below 200kev. This region of the gamma-ray spectra is vital to commonly used analysis algorithms for uranium and plutonium isotopic determination. Recently developed mechanical coolers have shown to have reduced low energy resolution degradation. Testing of these systems has been performed to evaluate their efficacy in common safeguards applications.