Low background shielding of HPGe detector.
National Radiation Protection Institute in Prague is equipped with 14 HPGe detectors with relative efficiency up to 150%. Steel shielding with one of these detectors (relative efficiency 100%) was chosen to be rebuilt to decrease minimum detectable activity (MDA). Additional lead and copper shielding was built up inside the original steel shielding to reduce the volume of the inner space and filled with nitrogen by means of evaporating liquid nitrogen. MDA values decreased for Compton background up to 0.67 of original value.
Trnková
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National Radiation Protection Institute, Bartoskova 28, 140 00 Prague 4, Czech Republic. lenka.trnkova@suro.cz
Rulík
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