Performance measurements of Al/CdTe/Pt pixel diode detectors

We developed Schottky CdTe detectors using Al as an anode electrode and measured their performances. We first fabricated monolithic detectors with four different thicknesses of 0.5, 0.75, 1.0, and 2.0 mm. An Al anode electrode was implemented with a guard-ring structure. For the 0.5 mm thick CdTe detector, an energy resolution of 1.2 keV (FWHM) at 122 keV was achieved at a temperature of −20 °C and a bias voltage of 400 V. Using the same technology, we next developed 8 × 8 pixel CdTe detectors, again with the four different thicknesses. The Al anode electrode was pixelated and the Pt cathode was made as a single plate. Signals from all pixels were successfully obtained and an energy resolution of 1.3 keV and 1.9 keV (FWHM) for 59.5 keV and 122 keV gamma-rays, was achieved at a temperature of −20 °C and a bias voltage of 400 V using the 0.5 mm thick CdTe detector. The energy resolution was nearly the same in each pixel.