Charge Division Readout of a Two-dimensional Germanium Strip Detector

Germanium strip detectors combine superior spectroscopy typical of germanium detectors with good spatial resolution. Our work has been to develop a 2-dimensional position readout of a 5 5 strip X-Y detector. The prototype device uses two capacitive charge division strings. Each string is read{out by two 13-bit ADCs, one on each end of the string. The four data channels are stored as an event list for subsequent processing. We form a response map over the detector surface in order to locate the position of each interaction with the spatial resolution of the strip pitch, in our case 9 mm. Cross-talk and non-linearities are removed using the response map. Energy resolution of 5.5 keV FWHM is achieved between 60 and 662 keV across the full surface of the detector.