Spectrometry of foton radiation (X rays or gamma rays) can be carried out using either a standard Si (Li) detectors (e.g. silicon detectors higly doped with lithium) or HPGe detectors (i.e. detectors produced from high pure germanium). Both types of detectors, needs to be cooled to a temperature of liquid nitrogen, due to the reduction of reverse current and electronic noise. The need to cool detectors is their major disadvantage, which is reflected in the need for mobile measurement.
The main idea of the research of semiconductor fotonic radiation detectors working at room temperature is to use semiconductors with high width of the energy gap. In particular, we research possibilities of use of alloys of two (such as GaAs, CdTe, InP, ...), three (e.g., CdZnTe, InAlP, ...), or up to four different elements, usually with a high proton number. Detectors made of such semiconductors, compared with silicon and germanium detectors, will have lower reverse current and greater detection efficiency for photonic radiation. Reduction of reverse current is less likely to cause by the thermal emission of electrons (or holes) to conduction (or valence) band. Magnification of detection efficiency is connected to the fact that the probability of photoelectric phenomena increases with the fifth power of proton number. Weakness of these detectors is their spectrometric resolution, which in comparison with cryogenic detectors is worse.
Linhart Vladimir | IEAP |