Investigation of the response function of the Schottky CdTe detector with guard-ring cathode through Monte Carlo calculation and measurement

We investigated the response function of a Schottky CdTe detector with a guard-ring cathode through Monte Carlo calculation using the MCNP code and measurement in order to apply the detector for the analysis of X-and γ-ray spectra in medical radio-diagnostic units for quality assurance and quality control of the systems. The CdTe detector has high potential as an X- and γ-ray spectrometer owing to compactness due to a large photon absorption cross section and high energy resolution. We measured the detector response function for various operating conditions, i.e., bias voltage and shaping time using an ²⁴¹Am source to find the optimum operating condition, and then measured the detector responses and full energy absorption efficiency for ²⁴¹Am, ¹⁵²Eu, ¹³³Ba and finally compared with the calculation. The experimental response functions are well reproduced by the MCNP code except for the part of the low energy tail due to charge trapping effect. (author)