Measurement of material uniformity using 3-D position sensitive CdZnTe gamma-ray spectrometers

He, Zhong; Li, W.; Knoll, G.F.; Wehe, D.K.; Stahle, C. M.

doi:10.1016/s0168-9002(99)00860-8

Cited by 27 publications

(13 citation statements)

References 7 publications

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“…If the exponential relation of the electron trapping from the cathode to the anode side (excluding the region very close to the anode) is used to calculate the electron mobility-lifetime product [14], the will be overestimated for the peripheral pixels, as can be seen in Fig. 12(a).…”

Section: Weighting Potentialmentioning

confidence: 99%

Analysis of detector response using 3-D position-sensitive CZT gamma-ray spectrometers

Zhang

2004

IEEE Trans. Nucl. Sci.

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Two 2.25-cm 3 CdZnTe gamma-ray spectrometers with three-dimensional (3-D) position sensitivity were constructed and tested. By using 11 11 pixellated anodes and depth-sensing techniques, individual spectral data for each of 4800 voxels were collected throughout the detector volume. Energy resolution of 1.11% and 1.14% FWHM at 662 keV were obtained for single-pixel events from these two detectors, respectively. Spatial variations of electron mobility-lifetime product, energy resolution, photopeak efficiency, and total efficiency have been observed and analyzed. This analysis provides a direct observation on the uniformity of detector response (due to material, weighting potential, and electric field distribution) in 3-D. Possible defects in the detector are identified. The impact of the spatial variation of detector response on a CZT gamma-ray spectrometer is discussed.

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Section: Weighting Potentialmentioning

confidence: 99%

Analysis of detector response using 3-D position-sensitive CZT gamma-ray spectrometers

Zhang

2004

IEEE Trans. Nucl. Sci.

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“…This offers a modular detector configuration with a minimal dead area at the periphery. Thirdly, as demonstrated by He et al [5,6], the depth-of-interaction (DOI) of gamma rays in pixelated CZT detectors can be derived using the ratio between signal amplitudes observed on both the anode and cathode (C/A ratio). For future ERPC detectors with relatively thick (2-4 mm) crystals, a similar scheme can be implemented to provide 3-D position sensitivity at an excellent resolution.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Development of a novel energy-resolved photon-counting detector for gamma ray imaging applications

et al. 2009

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In this paper, we present the design and preliminary performance evaluation of a novel energy-resolved photon-counting (ERPC) detector for gamma ray imaging applications. The prototype ERPC detector has an active area of 4.4 cm u 4.4 cm, which is pixelated into 128 u 128 square pixels with a pitch size of 350 Pm u 350 Pm. The current detector consists of multiple detector hybrids, each with a CdTe crystal of 1.1 cm u 2.2 cm u 1 mm, bump-bonded onto a customdesigned application-specific integrated circuit (ASIC). The ERPC ASIC has 2048 readout channels arranged in a 32u64 array. Each channel is equipped with pre-and shaping-amplifiers, a discriminator, peak/hold circuitry, and an analog-todigital converter (ADC) for digitizing the signal amplitude. In order to compensate for the pixel-to-pixel variation, two 8-bit DACs are implemented into each channel for tuning the gain and offset. The ERPC detector is designed to offer a high spatial resolution, a wide dynamic range of 12-200 keV and a good energy resolution of 3-4 keV. The hybrid detector configuration provides a flexible detection area that can be easily tailored for different imaging applications. The intrinsic performance of a prototype ERPC detector was evaluated with various gamma ray sources, and the results are presented.

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“…If we reduce the thickness by 3 mm we can keep a 3mm spatial resolution at the price of a slight reduction in sensitivity (from 85% to 70%). Another possibility is a direct measure of the DOI which is a Advances in Molecular Imaging fashionable subject with semiconductor detectors [32] [33] [34].…”

Section: The Problem Of Doi and High Count Ratementioning

confidence: 99%

An Alternative Model to Radon Transform for Gamma Ray Emission Tomography

Jeanguillaume¹,

Simonnet²,

Cavaro‐Ménard³

et al. 2017

AMI

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The Radon transform fits badly Single Photon Emission Tomography (SPECT). However, Thin Holes Collimator (THC) and Radon model are widely used. The CACAO project has been proposed to enhance the quality of SPECT images. CACAO is a short hand notation for computer aided collimation tomography. The main idea of this project is to use collimators with much larger holes to increase the sensitivity, and slightly longer holes to increase the spatial resolution. The acquisition sequence includes a translation. The Radon projection is replaced by a 2D sum. A dedicated reconstruction algorithm has been developed. If the physical advantage of the project in terms of sensitivity and spatial resolution is generally admitted, a question remains unanswered: Would the ill-posedness of the inverse problem ruin the quality of the reconstructed images? In this article, a representation of the 2D direct problem matrix is derived. This allows us to compare the two inverse problems (CACAO versus THC). The condition number was used for this comparison. We studied the variation of these condition numbers with several parameters. For a proper set of parameters, the CACAO inverse problem may appear easier to solve and more accurately than the THC one.

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Measurement of material uniformity using 3-D position sensitive CdZnTe gamma-ray spectrometers

Cited by 27 publications

References 7 publications

Analysis of detector response using 3-D position-sensitive CZT gamma-ray spectrometers

Analysis of detector response using 3-D position-sensitive CZT gamma-ray spectrometers

Development of a novel energy-resolved photon-counting detector for gamma ray imaging applications

An Alternative Model to Radon Transform for Gamma Ray Emission Tomography

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