Photon sources with minimized absorption for the calibration of semiconductor detectors

Homogeneous solid photon-sources for efficiency calibration of HPGe detectors in the energy range 20–60 keV, with minimized self-absorption and improved handling properties, were fabricated and tested as replacement for the most commonly used liquid and solid standards. The performance of these matrices as calibration sources was studied with three different ultra-low-background gamma spectrometry systems. Results showed reductions in self-absorption of approximately 40% and 360% at 22 keV as well as 15% and 200% at 30 keV in relation to the liquid and solid sources, respectively. The agreement between the experimental data and Monte Carlo simulations was better than 5% for the detectorʹs efficiency even at very low energies.