Cadmium Telluride Detectors for Gamma Dose-Rate Meters

摘要

The response of a 0.25-mm CdTe detector has been calculated for photon energies ranging from 0.06 to 5.0 MeV using the computer code CYLTRAN. Results show that the response is highly energy dependent, varying by almost three decades over this energy range. The response also depends significantly on the amount of scattering material adjacent to the detector. Some additional calculations show that the response can be made more uniform by using a lead/tin filter and by employing more than one energy-discrimination level, but good uniformity of response is difficult to achieve. At 2 MeV a response of 2.1 x 10.7 counts/(mm squared gray) was found which is essentially the same as for silicon of equivalent thickness. Measurements with a commercial CdTe detector confirmed the results of the calculations, although comparison of measured and calculated results indicated that the detector was not as thick as its specified 0.25 mm.