3 research outputs found
Recommended from our members
Performance of CdZnTe coplanar-grid gamma-ray detectors
CdZnTe crystals grown using the high-pressure Bridgman method exhibit many properties that are desirable for radiation detector fabrication, such as high resistivity, stable operation, relative ease of processing, and the availability of large volume crystals. However, as is common with other compound semi-conductor materials, currently available CdZnTe crystals have poor charge transport characteristics. This seriously the spectral performance of detectors, especially in gamma-ray detection. The coplanar-grid detection technique was recently developed to address such charge collection problems. This technique was first demonstrated using a 5 mm cube CdZnTe detector, and a dramatic improvement in spectral response has been achieved. These early results verified the effectiveness of this technique and suggested that large-volume gamma-ray detectors with high energy resolution can be realized. To further the development of such detectors, it is important to understand the various factors that affect detector performance. The purpose of this paper is to examine the effects of material properties on the spectral performance of CdZnTe coplanar-grid detectors. Theoretical spectral response is to show the level of performance that can be achieved given the typical carrier mobility-lifetime ({mu}{tau}) properties of present-day materials. Nonuniformity in the charge transport properties of the material, which could limit the energy resolution of the detectors, has been studied experimentally and some of the results are presented here
Recommended from our members
Deep electronic levels in high-pressure Bridgman Cd{sub 1-x}Zn{sub x}Te
The behavior of deep electronic levels was studied as a function of Zn concentration in CdZnTe crystals grown by the high-pressure Bridgman technique using thermoelectric effect spectroscopy. A significant increase of the thermal ionization energies of hole traps was observed with the increasing Zn content of the ternary compound. The effect explains the stronger hole trapping and the resulting much shorter hole lifetime usually observed in CdZnTe as compared to CdTe. The behavior also suggests increased carrier recombination and explains the strong deterioration of electron collection in detectors fabricated from CdZnTe of high Zn concentration
Recommended from our members
A study of the timing properties of Cd{sub 0.9}Zn{sub 0.1}Te
CdZnTe has become a material of great interest in the field of X- and {gamma}-ray imaging, and shows great promise as a highly efficient, room-temperature operation detector. However, data on the timing resolution obtainable with this material is scarce. It is known that CdZnTe, in common with all compound semi-conductors, gives pulses of varying rise-time depending on the interaction location, hence causing a broadening of the time spectrum. We therefore assembled and characterized an appropriate electronic measuring set-up and took data with 2 different sets of detectors, varying the experimental parameters such as bias voltage, threshold and temperature during the course of the experiment. The results obtained with planar detectors of 9 mm{sup 2} {times} 2 mm thick were superior to the results obtained with detectors of 25 mm{sup 2} {times} 10 mm thick, even when the difference in effective bias field strength is considered. Timing resolutions of 5.3 ns and 20.9 ns (FWHM) respectively were obtained. Reducing the temperature to 0{degree}C reduced the resolution to 4.5 ns, thereby indicating that the performance is limited by signal-to-noise ratio considerations