Characteristic Performance Evaluation of a New SAGe Well Detector for Small and Large Sample Geometries

• Published in: IEEE transactions on nuclear science 2016-06, Vol.63 (3), p.1570-1577
• Main Authors: Adekola, A. S., Colaresi, J., Douwen, J., Jaderstrom, H., Mueller, W. F., Yocum, K. M., Carmichael, K.
• Format: Article
• Language: English
• Subjects: Detectors; Energy measurement; Energy resolution; Environmental application measurements; gamma rays; Geometry; Lead; low capacitance germanium device; minimum detectable activity and concentration; Performance evaluation; radiological; SAGe Well detector; small anode; Thorium; true coincidence summing
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2015.2508676

Environmental scientific research requires a detector that has sensitivity low enough to reveal the radiological content for the presence of potential contaminants in the sample at a reasonable counting time. CANBERRA developed a germanium detector geometry called Small Anode Germanium (SAGe) Well detector. The SAGe Well detector is a new type of low capacitance device manufactured using small anode technology capable of advancing many environmental scientific research applications. The performance of this detector has been evaluated for a range of sample sizes and geometries counted inside the well, and on the end cap of the detector. The detector has energy resolution performance similar to semi-planar detectors, and offers significant improvement over the existing coaxial and Well detectors. Energy resolution performance of 750 eV Full Width at Half Maximum (FWHM) at 122 keV \gamma -ray energy and resolution of 2.0-2.3 keV FWHM at 1332 keV \gamma -ray energy are guaranteed for detector volumes up to 425 ~\hbox{cm}^{3} . The SAGe Well detector offers an optional 28 mm well diameter with the same energy resolution performance as the standard 16 mm well. Such outstanding performance will benefit environmental applications in revealing the detailed radionuclide content of samples, particularly at low energy. The detector is compatible with electric coolers without any sacrifice in performance and supports the CANBERRA Mathematical efficiency calibration method (In situ Object Calibration Software or ISOCS, and Laboratory SOurceless Calibration Software or LabSOCS). In addition, the SAGe Well detector supports true coincidence summing available in the ISOCS/LabSOCS framework. The improved resolution performance of this new device greatly enhances its detection sensitivity for a range of sample sizes and geometries counted inside the well. This results in lower minimum detectable concentrations (MDC) compared to Traditional Well detectors. The SAGe Well detectors are compatible with Marinelli beakers and compete very well with semi-planar and coaxial detectors for large samples in many applications.