CdTe stacked detectors for gamma-ray detection

We describe a stacked detector made of thin CdTe diode detectors. By using a thin CdTe device, we can overcome the charge loss problem due to the small mobility and short lifetime of holes in CdTe or CdZnTe detectors. However, a CdTe detector with a thickness of more than 5 mm is needed for adequate detection efficiency for gamma-rays of several hundred keV. Good energy resolution and good peak detection efficiency are difficult to obtain using such a thick CdTe detector. The stacked detector enabled us to realize a detector with both high energy resolution (/spl sim/1%) and good efficiencies for gamma-rays up to several hundred keV. In this paper, we report the advantage of CdTe thin detectors and the performance of CdTe stacked detectors made of ten layers of a 0.5 mm thick CdTe diode detectors with a surface area of 21.5 mm/spl times/21.5 mm.