Position sensitivity of a segmented planar Ge detector

A method to extract depth of interaction information for γ-rays in a segmented planar Ge detector is presented. The method is demonstrated on signals from a segmented detector which were stored by a digital oscilloscope event by event and analysed off-line. Event samples were acquired for different interaction points in the detector. A Compton scatter coincidence detection technique ensured that the event samples were highly enriched in single-interaction events. By analysing pulse shapes and the relative timing between anode pulses and the pulses from the irradiated cathode segment, a position sensitivity of 1–2 mm in the depth direction was deduced. A similar transverse position sensitivity was inferred by studying image charge pulses on neighbouring segments.