Fluorescence-based method for estimating the dead layer thickness of a broad-energy germanium detector

A fluorescence-based method is proposed in this paper to estimate the front dead layer thickness of a broad-energy germanium detector. The germanium fluorescence was induced by the 57Co 14.4 keV gamma radiation incident on the dead layer. The count ratio between germanium fluorescence and the transmitted probe photons was experimentally measured and then compared with a series of Geant4 calculations for thickness determination. The method is sensitive to dead layer thickness owing to direct measurement of the thickness-dependent fluorescence and is independent of probe intensity and materials intervened between the source and the detector by using count ratio. The approach is anticipated to have a general application to surface studies of various types of germanium detectors.