Charge sharing in common-grid pixelated CdZnTe detectors

Kim, Jae Cheon; Anderson, Sandra; Kaye, Willy; Zhang, Feng; Zhu, Yuefeng; Kaye, S.; He, Zhong

doi:10.1016/j.nima.2011.06.038

Cited by 88 publications

(59 citation statements)

References 14 publications

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“…As the maturity of the above-mentioned materials for radiation detection applications ensures a complete charge collection at the electrodes [5,7,12], charge sharing and related effects were naturally ascribed to carriers thermal diffusion in inter-electrode gaps [4,5,13,14] and to an extended charge cloud size [5,12,14,15].…”

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confidence: 99%

“…to study chargesharing effects without the assumption of an extended carriers cloud size [5,12,14,15]. A straightforward consequence of eqs.…”

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confidence: 99%

“…It is worth noting that the geometry under investigation is equivalent, from the point of view of the electric-field topology, to many detectors with segmented electrodes in silicon [1,3,9] and CZT [7,15]. In fact, despite in such works the electric field is mostly perpendicular to the top active area of the detector, the excess charge carriers drift along the electric-field lines, which can be continuously deformed into the configuration shown in fig.…”

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confidence: 99%

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Measurement and modelling of anomalous polarity pulses in a multi-electrode diamond detector

Forneris¹,

Grilj

Jakšić

et al. 2013

EPL

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-In multi-electrode detectors, the motion of excess carriers generated by ionizing radiation induces charge pulses at the electrodes, whose intensities and polarities depend on the geometrical, electrostatic and carriers' transport properties of the device. The resulting chargesharing effects may lead to bipolar currents, pulse height defects and anomalous polarity signals affecting the response of the device to ionizing radiation. This latter effect has recently attracted attention in commonly used detector materials, but different interpretations have been suggested, depending on the material, the geometry of the device and the nature of the ionizing radiation. In this letter, we report on the investigation in the formation of anomalous polarity pulses in a multi-electrode diamond detector with buried graphitic electrodes. In particular, we propose a purely electrostatic model based on the Shockley-Ramo-Gunn theory, providing a satisfactory description of anomalous pulses observed in charge collection efficiency maps measured by means of Ion Beam Induced Charge (IBIC) microscopy, and suitable for a general application in multielectrode devices and detectors.

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mentioning

confidence: 99%

“…to study chargesharing effects without the assumption of an extended carriers cloud size [5,12,14,15]. A straightforward consequence of eqs.…”

mentioning

confidence: 99%

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confidence: 99%

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Measurement and modelling of anomalous polarity pulses in a multi-electrode diamond detector

Forneris¹,

Grilj

Jakšić

et al. 2013

EPL

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“…This phenomenon is also termed charge sharing. 26 This makes difficult to perform scatter and cross talk correction to separate thallium-201 and technetium-99m peak.…”

Section: Discussionmentioning

confidence: 99%

“…The mean injected dose of thallium-201 during stress was 82 ± 19 MBq (range 68-115 MBq) and the mean injected dose of technetium99m-sestamibi at rest was 314 ± 41 MBq (range 265-457 MBq). The DI-HS-MPI protocol was completed in 22.4 ± 4.5 minutes [18][19][20][21][22][23][24][25][26][27]. One hundred percent of the MPI were ranked as being of either good or excellent in quality.…”

Section: Population Characteristicsmentioning

confidence: 99%

Stress thallium-201/rest technetium-99m sequential dual-isotope high-speed myocardial perfusion imaging validation versus invasive coronary angiography

Barone-Rochette

Leclere

Calizzano

et al. 2015

Journal of Nuclear Cardiology

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Feasibility of multi‐contrast imaging on dual‐source photon counting detector (PCD) CT: An initial phantom study

et al. 2019

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Purpose Photon‐counting‐detector‐computed tomography (PCD‐CT) allows separation of multiple, simultaneously imaged contrast agents, such as iodine (I), gadolinium (Gd), and bismuth (Bi). However, PCDs suffer from several technical limitations such as charge sharing, K‐edge escape, and pulse pile‐up, which compromise spectral separation of multi‐energy data and degrade multi‐contrast imaging performance. The purpose of this work was to determine the performance of a dual‐source (DS) PCD‐CT relative to a single‐source (SS) PCD‐CT for the separation of simultaneously imaged I, Gd, and Bi contrast agents. Methods Phantom experiments were performed using a research whole‐body PCD‐CT and head/abdomen‐sized phantoms containing vials of different I, Gd, Bi concentrations. To emulate a DS‐PCD‐CT, the phantoms were scanned twice on the SS‐PCD‐CT using different tube potentials for each scan. A tube potential of 80 kV (energy thresholds = 25/50 keV) was used for low‐energy tube, while the high‐energy tube used Sn140 kV (Sn indicates tin filter) and thresholds of 25/90 keV. The same phantoms were scanned also on the SS‐PCD‐CT using the chess acquisition mode. In chess mode, the 4 × 4 subpixels within a macro detector pixel are split into two sets based on a chess‐board pattern. With each subpixel set having two energy thresholds, chess mode allows four energy‐bin data sets, which permits simultaneous multi‐contrast imaging. Because of this design, only 50% area of each detector pixel is configured to receive photons of a pre‐defined threshold, leading to 50% dose utilization efficiency. To compensate for this dose inefficiency, the radiation dose for this scan was doubled compared to DS‐PCD‐CT. A 140 kV tube potential and thresholds = 25/50/75/90 keV were used. These settings were determined based on the K‐edges of Gd, and Bi, and were found to yield good differentiation of I/Gd/Bi based on phantom experiments and other literature. The energy‐bin images obtained from each scan (scan pair) were used to generate I‐, Gd‐, Bi‐specific image via material decomposition. Root‐mean‐square‐error (RMSE) between the known and measured concentrations was calculated for each scenario. A 20‐cm water cylinder phantom was scanned on both systems, which was used for evaluating the magnitude of noise, and noise power spectra (NPS) of I/Gd/Bi‐specific images. Results Phantom results showed that DS‐PCD‐CT reduced noise in material‐specific images for both head and body phantoms compared to SS‐PCD‐CT. The noise level of SS‐PCD was reduced from 2.55 to 0.90 mg/mL (I), 1.97 to 0.78 mg/mL (Gd), and 0.85 to 0.74 mg/mL (Bi) using DS‐PCD. NPS analysis showed that the noise texture of images acquired on both systems is similar. For the body phantom, the RMSE for SS‐PCD‐CT was reduced relative to DS‐PCD‐CT from 10.52 to 2.76 mg/mL (I), 7.90 to 2.01 mg/mL (Gd), and 1.91 to 1.16 mg/mL (Bi). A similar trend was observed for the head phantom: RMSE reduced from 2.59 (SS‐PCD) to 0.72 (DS‐PCD) mg/mL (I), 2.02 to 0.58 mg/mL (Gd), and 0.85 to 0.57 mg/mL (Bi). Co...

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Charge sharing in common-grid pixelated CdZnTe detectors

Cited by 88 publications

References 14 publications

Measurement and modelling of anomalous polarity pulses in a multi-electrode diamond detector

Measurement and modelling of anomalous polarity pulses in a multi-electrode diamond detector

Stress thallium-201/rest technetium-99m sequential dual-isotope high-speed myocardial perfusion imaging validation versus invasive coronary angiography

Feasibility of multi‐contrast imaging on dual‐source photon counting detector (PCD) CT: An initial phantom study

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