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Title: Performance Characteristics of Frisch-Ring CdZnTe Detectors

Abstract

The performance characteristics of Frisch-ring CdZnTe (CZT) detectors are described and compared with other types of CZT devices. The Frisch-ring detector is a bar-shaped CZT crystal with a geometrical aspect ratio of /spl sim/1:2. The side surfaces of the detector are coated with an insulating layer followed by a metal layer deposited directly upon the insulator. The simple design operates as a single-carrier device. Despite the simplicity of this approach, its performance depends on many factors that are still not fully understood. We describe results of testing several detectors fabricated from CZT material produced by different vendors and compare the results with numerical simulations of these devices.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914132
Report Number(s):
BNL-78700-2007-JA
Journal ID: ISSN 0018-9499; IETNAE; TRN: US0801565
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Trans. Nucl. Sci.; Journal Volume: 53; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ASPECT RATIO; DESIGN; PERFORMANCE; TESTING; NSLS; national synchrotron light source

Citation Formats

Bolotnikov,A., Camarda, G., Carini, G., Fiederle, M., Li, L., McGregor, D., McNeil, W., Wright, G., and James, R. Performance Characteristics of Frisch-Ring CdZnTe Detectors. United States: N. p., 2006. Web. doi:10.1109/TNS.2006.871509.
Bolotnikov,A., Camarda, G., Carini, G., Fiederle, M., Li, L., McGregor, D., McNeil, W., Wright, G., & James, R. Performance Characteristics of Frisch-Ring CdZnTe Detectors. United States. doi:10.1109/TNS.2006.871509.
Bolotnikov,A., Camarda, G., Carini, G., Fiederle, M., Li, L., McGregor, D., McNeil, W., Wright, G., and James, R. Sun . "Performance Characteristics of Frisch-Ring CdZnTe Detectors". United States. doi:10.1109/TNS.2006.871509.
@article{osti_914132,
title = {Performance Characteristics of Frisch-Ring CdZnTe Detectors},
author = {Bolotnikov,A. and Camarda, G. and Carini, G. and Fiederle, M. and Li, L. and McGregor, D. and McNeil, W. and Wright, G. and James, R.},
abstractNote = {The performance characteristics of Frisch-ring CdZnTe (CZT) detectors are described and compared with other types of CZT devices. The Frisch-ring detector is a bar-shaped CZT crystal with a geometrical aspect ratio of /spl sim/1:2. The side surfaces of the detector are coated with an insulating layer followed by a metal layer deposited directly upon the insulator. The simple design operates as a single-carrier device. Despite the simplicity of this approach, its performance depends on many factors that are still not fully understood. We describe results of testing several detectors fabricated from CZT material produced by different vendors and compare the results with numerical simulations of these devices.},
doi = {10.1109/TNS.2006.871509},
journal = {IEEE Trans. Nucl. Sci.},
number = 2,
volume = 53,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • Frisch-ring CdZnTe detectors have demonstrated both good energy resolution, <1% FWHM at 662 keV, and good efficiency in detecting gamma rays, highlighting the strong potential of CdZnTe materials for such applications. We are designing a hand-held gamma-ray spectrometer based on Frisch-ring detectors at Brookhaven National Laboratory. It employs an 8 times 8 CdZnTe detector array to achieve a high volume of 19.2 cm3, so greatly improving detection efficiency. By using the front-end application-specific integrated circuits (ASICs) developed at BNL, this spectrometer has a small profile and high energy-resolution. It includes a signal processing circuit, digitization and storage circuits, a high-voltagemore » module, and a universal serial bus (USB) interface. In this paper, we detail the system's structure and report the results of our tests with it.« less
  • Semiconductor Frisch grid radiation detectors have been manufactured and tested with encouraging results. Resolution enhancement occurs as a result of combining the geometric weighting effect, the small pixel effect and the Frisch grid effect. The devices are operated at ambient temperature without any pulse shape correction, rejection and compensation techniques. The new devices are manufactured from CdZnTe and do not require any cooling for operation. The geometrically weighted detectors have only one signal output to a standard commercially available Ortec 142A preamplifier. The detectors operate with simple commercially available NIM electronics, hence the device design can be coupled to anymore » typical NIM system without the need for special electronic instruments or circuits. Geometrically weighted detectors that are 1 cubic centimeter in volume were fabricated from counter grade material, yet have shown room temperature energy resolution of 7.5% FWHM (at 29 C) for {sup 57}Co 122 keV gamma rays and 2.68% FWHM (at 23 C) for {sup 137}Cs 662 keV gamma rays.« less
  • CdZnTe wide band gap compound semiconducting material offers promise as a room temperature operated gamma ray spectrometer. Position-dependent free charge carrier losses during transport can prevent efficient charge carrier extraction from semiconductor detectors and severely reduce energy resolution. Hole trapping losses in CdZnTe radiation detectors are far worse than electron trapping losses and resolution degradation in CdZnTe detectors results primarily from severe hole trapping during transport. Coplanar radiation detectors improved energy resolution by sensing the induced charge primarily from the motion of electrons. Demonstrated is an alternative approach to single free charge carrier sensing, in which a parallel strip Frischmore » grid is fabricated on either side of a parallelepiped block. The detectors are three terminal devices, but require only one preamplifier for the output signal. The prototype devices demonstrate a considerable increase in energy resolution when operated in the true Frisch grid mode rather than the planar mode, with a demonstrated room temperature energy resolution for 662 keV gamma rays of 5.91 % at FWHM for a 10 mm x 2 mm x 10 mm device. Presently, high surface leakage currents prevent large voltages from being applied to the devices, which ultimately reduces their maximum achievable energy resolution. Further improvements are expected with the realization of reduced surface leakage currents.« less
  • We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We presentmore » the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less
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