Position Sensitive Gamma Ray Detectors Using Resistive Charge Division Readout

The analysis of an orthogonal strip, two-dimensional position sensitive high purity germanium gamma ray detector is discussed. Position sensitivity is obtained by connecting each electrode strip on the detector to a resistor network and the ends of the network to charge sensitive preamplifiers. The difference of the voltage pulses at the output of each preamplifier is proportional to the position at which the charge entered the resistor network and the sum of the voltage pulses is proportional to the energy of the detected gamma ray. The results of the analysis of the energy and spatial signal noise show that the position resolution is proportional to the square root of the filter amplifier´s output pulse time constant and that for energy measurement the resolution is maximized at the filter amplifier´s noise corner time constant. The electronic noise filtering system and experimental noise measurement results are presented.