3D position sensitivity of a highly segmented Ge detector

The 3D position resolution of a planar HPGe detector with a 25-fold segmented cathode contact has been studied. The measurements were performed with a collimated 137Cs γ-ray pencil beam and a coincidence scattering technique that selects single interaction events at well-defined irradiation points. The γ rays scattered at 90∘, depositing 374 keV energy in the detector, were registered and the pulse shapes from the irradiated segment and three neighboring segments were analyzed. The resulting average 3D position sensitivity for single γ-ray interactions is estimated at 0.4 mm