CZT is a room temperature semiconductor that directly converts x-ray or gamma-ray photons into electrons. CZT is a unique semiconductor compared with Silicon and Germanium detectors, in that CZT operates at room temperature and can process >10 million photons / second /mm^2. Additionally, CZT's spectroscopic resolution clearly out performs any commercially available Scintallator. The unique combination of spectroscopy and very high count rate capability at room temperature makes CZT an ideal detector solution for Medical, Industrial, Homeland Security and Laboratory applications.
How does CZT work?
CZT detectors are fabricated with very thin metalized electrode geometries deposited on the detector surfaces. These electrodes are then electrically biased creating a difference in electrical potential within the detector volume. When ionizing radiation interacts with the CZT crystal, electron hole pairs are created in proportion to the energy of the incoming radiation. The negatively charged electrons and positively charged holes then migrate to the oppositely charged electrode where they are collected. The resulting charge pulse is then detected by the preamplifier, which produces a voltage pulse whose height is proportional to the incident energy of the incoming photon. The signal from the preamplifier is then fed into a shaping amplifier that converts the signal into a Gaussian pulse and amplifies it. The signal can then be fed into a standard counting system or Multi Channel Analyzer (MCA) to generate the characteristic spectrum for the incoming photons.
Quality assessment (Characterization) of the CZT material is performed at four specific stations (see graphic below) through the standard processing of the CZT detectors. All CZT detector material is tested at these four characterization steps during the processing of the material. Additional testing of mounted detectors, detector assemblies, finished detectors, etc. is performed according to the design specification that is determined jointly by the eV engineering group and our customers.
Characterization of CZT at eV Products
ALL detector products manufactured by eV Products use CZT as the detection material. By carefully measuring the quality of the CZT material early and often in our detector manufacturing process, we are able to eliminate material that does not meet our standards early in the process. Additionally, we are able to ‘mine’ every ingot and every slice within that ingot to match the material produced in our Crystal Growth department to specific customer application needs.
The four numbered areas identify where characterization of the CZT material is performed.