Detection efficiency for an ultraviolet photon counting imaging system based on the Ge induction readout

The detection efficiency, assumed proportional to the count rate, of an ultraviolet photon counting imaging system based on the Ge induction readout is studied. For the Ge induction readout, the system count rate with different Ge layer resistances, Ge layer thicknesses and ceramic thicknesses are tested under different light intensities. The test results show that the system count rate with a high resistance in the Ge layer is lower than that with a low resistance in the Ge layer; further, the imaging area decreases as the Ge layer resistance increases under high photon flux. Moreover the system count rate with a thick Ge layer is lower than that with a thin Ge layer. In addition, the system count rate with 2-mm ceramic is higher than that with 1.5- and 3-mm ceramic. The above observation should be considered when designing an ultraviolet photon counting imaging detector based on the Ge induction readout.