Speaker
Description
Mirion Technologies has developed detectors to cope with the requirements
of low radioactivity measurement: the Specialty Ultra Low Background (S-ULB) detectors. For the construction of a S-ULB detector, each element that enters its composition must be selected carefully to reduce as much as possible the intrinsic radioactivity of the detector itself. The S-ULB detectors achieved a consistent intrinsic radioactivity of the order of a few hundred counts per day and per kg of Ge.
Specific needs for low radioactivity measurements are addressed. For example, the detector orientation of the BEGe unit can be changed and modified to have two detectors facing each other. This configuration increases the solid angle coverage by a factor and provides optimized efficiency for large sample measurement. Increase of the crystal diameter of the BEGe detector up to 105 mm leads to a large surface ideal for large sample measurements. The ratio of active volume over internal radioactivity becomes even better. For measurements of small volume samples, the SAGe™ Well detector with a well diameter of 21 mm provides close to 4PI solid angle coverage. Each detector can have a specific design, low radioactivity material, with similar standard HPGe energy resolution: 600 eV at 122 keV and 1.7 keV at 1332 keV for a 1.2 kg BEGe detector. For low radioactivity techniques, this led to better minimum detection activity or reduction of measurement time. The advantages and the performance of the latest developments of the Mirion S-ULB detectors are presented here.