High-resolution ionization detector and array of such detectors
First Claim
1. A high-resolution, ionization detector comprising:
- an ionization substrate having a first surface and a second surface opposing the first surface;
a first electrode disposed at the first surface;
a second electrode disposed at the second surface;
a reference pattern of conductive or semiconductive material which divides the ionization substrate into an interaction region, a measurement region and a pervious region which separates the interaction and measurement regions wherein the pervious region defines a reference plane to measure charge carrier movement in the measurement region and directs charge carrier flow within the substrate;
voltage potential circuits for applying voltage potentials to the reference pattern of material and to the first and second electrodes so that a bias voltage is applied across substantially the entire substrate and so the voltage potential applied to the reference pattern is between the voltage potentials applied to the first and second electrodes, wherein charge carriers of a first polarity type move from the interaction region, through the pervious region and into the measurement region; and
a signal measurement circuit for measuring at the second electrode a signal generated by the charge carriers of the first polarity type moving from the interaction region, through the pervious region and within the measurement region between the pervious region and the second surface wherein the substrate also has a third surface and a fourth surface opposing the third surface between the first and second surfaces and wherein the reference pattern includes a first strip disposed at the third surface and a second strip disposed at the fourth surface.
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Abstract
A high-resolution ionization detector and an array of such detectors are described which utilize a reference pattern of conductive or semiconductive material to form interaction, pervious and measurement regions in an ionization substrate of, for example, CdZnTe material. The ionization detector is a room temperature semiconductor radiation detector. Various geometries of such a detector and an array of such detectors produce room temperature operated gamma ray spectrometers with relatively high resolution. For example, a 1 cm3 detector is capable of measuring 137Cs 662 keV gamma rays with room temperature energy resolution approaching 2% at FWHM. Two major types of such detectors include a parallel strip semiconductor Frisch grid detector and the geometrically weighted trapezoid prism semiconductor Frisch grid detector. The geometrically weighted detector records room temperature (24° C.) energy resolutions of 2.68% FWHM for 137Cs 662 keV gamma rays and 2.45% FWHM for 60Co 1.332 MeV gamma rays. The detectors perform well without any electronic pulse rejection, correction or compensation techniques. The devices operate at room temperature with simple commercially available NIM bin electronics and do not require special preamplifiers or cooling stages for good spectroscopic results.
85 Citations
37 Claims
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1. A high-resolution, ionization detector comprising:
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an ionization substrate having a first surface and a second surface opposing the first surface;
a first electrode disposed at the first surface;
a second electrode disposed at the second surface;
a reference pattern of conductive or semiconductive material which divides the ionization substrate into an interaction region, a measurement region and a pervious region which separates the interaction and measurement regions wherein the pervious region defines a reference plane to measure charge carrier movement in the measurement region and directs charge carrier flow within the substrate;
voltage potential circuits for applying voltage potentials to the reference pattern of material and to the first and second electrodes so that a bias voltage is applied across substantially the entire substrate and so the voltage potential applied to the reference pattern is between the voltage potentials applied to the first and second electrodes, wherein charge carriers of a first polarity type move from the interaction region, through the pervious region and into the measurement region; and
a signal measurement circuit for measuring at the second electrode a signal generated by the charge carriers of the first polarity type moving from the interaction region, through the pervious region and within the measurement region between the pervious region and the second surface wherein the substrate also has a third surface and a fourth surface opposing the third surface between the first and second surfaces and wherein the reference pattern includes a first strip disposed at the third surface and a second strip disposed at the fourth surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A high-resolution, ionization detector comprising:
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an ionization substrate having a first surface and a second surface opposing the first surface;
a first electrode disposed at the first surface;
a second electrode disposed at the second surface;
a reference pattern of conductive or semiconductive material which divides the ionization substrate into an interaction region, a measurement region and a pervious region which separates the interaction and measurement regions wherein the pervious region defines a reference plane to measure charge carrier movement in the measurement region and directs charge carrier flow within the substrate;
voltage potential circuits for applying voltage potentials to the reference pattern of material and to the first and second electrodes so that a bias voltage is applied across substantially the entire substrate and so the voltage potential applied to the reference pattern is between the voltage potentials applied to the first and second electrodes, wherein charge carriers of a first polarity type move from the interaction region, through the pervious region and into the measurement region; and
a signal measurement circuit for measuring at the second electrode a signal generated by the charge carriers of the first polarity type moving from the interaction region, through the pervious region and within the measurement region between the pervious region and the second surface wherein the substrate also has a third surface and a fourth surface opposing the third surface between the first and second surfaces and wherein the reference pattern is a Frisch grid ring disposed at the third and fourth surfaces.
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34. A high-resolution, ionization detector comprising:
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an ionization substrate having a first surface and a second surface opposing the first surface;
a first electrode disposed at the first surface;
a second electrode disposed at the second surface;
a reference pattern of conductive or semiconductive material which divides the ionization substrate into an interaction region, a measurement region and a pervious region which separates the interaction and measurement regions wherein the pervious region defines a reference plane to measure charge carrier movement in the measurement region and directs charge carrier flow within the substrate;
voltage potential circuits for applying voltage potentials to the reference pattern of material and to the first and second electrodes so that a bias voltage is applied across substantially the entire substrate and so the voltage potential applied to the reference pattern is between the voltage potentials applied to the first and second electrodes, wherein charge carriers of a first polarity type move from the interaction region, through the pervious region and into the measurement region; and
a signal measurement circuit for measuring at the second electrode a signal generated by the charge carriers of the first polarity type moving from the interaction region, through the pervious region and within the measurement region between the pervious region and the second surface wherein the substrate also has a third surface and a fourth surface opposing the third surface between the first and second surfaces and wherein the reference pattern is a non-contacting Frisch grid spaced away from the third and fourth surfaces. - View Dependent Claims (35, 36, 37)
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Specification