Development of CdTe pixel detectors for Compton cameras

We report our development of CdTe pixel detectors for Si/CdTe semiconductor Compton cameras. We have constructed a prototype of a Si/CdTe Compton camera, consisting of six layered double-sided silicon strip detectors and three CdTe pixel detectors. By using this prototype, we have demonstrated the concept of the Si/CdTe Compton cameras. We have successfully obtained Compton reconstructed images for 80–662 keV gamma-rays. The achieved angular resolution is about 4 degrees for 511 keV gamma-rays. The energy resolution is 14 keV (FWHM) at 511 keV. In order to improve the performance of the Compton camera, we have evaluated all CdTe pixel detectors we have constructed. We found that the II–VV curve is helpful to select good detectors.