A NEW CDZNTE DETECTOR SYSTEM FOR LOW-ENERGY GAMMA-RAY MEASUREMENT

The major problems with CdTe-based radiation detectors have been exces s noise and operation instabilities due to poor charge-collection effi ciency. New fabrication methods have removed these problems and made C dZnTe detectors attractive in applications where compact room-temperat ure detectors with high stopping efficiency are required. The improvem ents in this detector technology are demonstrated. The noise performan ce of these detectors is comparable with that of silicon detectors. Ga mma-ray densitometry and tomography are typical applications where fas t and compact detector systems are required. A system based on a delay -line shaping amplifier circuit has been developed for this purpose, b ut is also applicable in other high-count-rate applications. The princ iple of operation and the test results of this system are presented.