ASIC with Multiple Energy Discrimination for High-Rate Photon Counting Applications

Geronimo, Gianluigi; Dragone, A.; Grosholz, J.; O’Connor, Paul; Vernon, E.

doi:10.1109/nssmic.2006.355951

Cited by 7 publications

(6 citation statements)

References 21 publications

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“…The stopping power exceeds that of both CdTe and CZT (see Figure 1) and 2 mm thickness is enough to stop virtually 100% of 70 keV and 87.9% of 140 keV X-ray photons. LYSO:Ce has a decay time of ~40 ns, and with a 5 th order shaping amplifier 95% of the light should be collected with a peaking time of ~140 ns [41,42], which would lead to a theoretical count rate capability of ~7 MHz. Taking into account SNR and Equivalent Noise Charge (ENC) this value would likely be reduced to ~1 MHz.…”

Section: Conceptual Design Of Scintillator-based Pcdmentioning

confidence: 99%

Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application

et al. 2019

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With the goal of developing a low-cost scintillator-based photon counting detector (PCD) with high dose efficiency suitable for CT, the light transport characteristics in LYSO:Ce detectors containing Laser Induced Optical Barriers (LIOB) are simulated. Light confinement and light collection efficiencies (LCE) are studied for a variety of optical barrier patterns and properties (refractive index (RI) and barrier/crystal interface roughness). Up to 80% confinement is achievable with a simple pixel pattern with one barrier wall separating each pixel coupled one-toone to a photodetector (PD) pixel. Confinement is heavily dependent on barrier properties, and rough interfaces and higher RI results in increased cross-talk. Three approaches to enhance performance beyond the basic pattern are explored: 1) Multiple barrier walls separating each crystal pixel. 2) Introduction of long and short range confinement by having multiple crystal pixels per PD pixel. 3) Combination of LIOB and Laser Ablation. 1) Is effective for rough interfaces where confinement can be increased by up to 24% for double compared to single walls. 2) Results in high confinement in the pixel centered on the PD pixel, but lower confinement closer to the PD edge. This feature may be explored to achieve spatial resolution beyond the PD pixel size using light sharing based positioning algorithms. 3) Can increase confinement for smooth interfaces using a smooth ablation in the bottom part of the crystal. A general trend across all configurations is a trade-off between light confinement and LCE. The LCE attainable is found comparable to that for mechanically pixelated arrays. While the confinement achievable with LIOB is always lower compared to a mechanically pixelated array, the former may offer a high level of flexibility in terms of detector design. This, in combination with the possibility to fabricate sub-mm pixels in a cost-effective manner, makes LIOB a promising technology for scintillator-based PCDs.

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Section: Conceptual Design Of Scintillator-based Pcdmentioning

confidence: 99%

Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application

et al. 2019

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“…The HERMES4 ASIC, based upon 350-nm CMOS technology, offers 32 channels of low-noise charge amplification, high-order shaping with baseline stabilisation, and peak detection for various low-noise analogue/digital processing (Fig. 7(a)) [33,34]. For reducing stray capacitance and for suppressing signals stemming from electrical interconnections, each sensor segment in the array is wire-bonded directly to the input of the front-end readout channel (Fig.…”

Section: Readout Electronics and Peripheriesmentioning

confidence: 99%

Customisable X-ray fluorescence photodetector with submicron sensitivity using a ring array of silicon p-i-n diodes

Yoon¹

2018

Sci Rep

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The research and development of silicon-based X-ray fluorescence detectors achieved its submicron sensitivity. Its initial use is intended for in-situ beam monitoring at advanced light-source facilities. The effectively functioning prototype fully leveraged technologies and techniques from a wide array of scientific disciplines: X-ray fluorescence technique, photon scattering and spectroscopy, astronomical photometry, semiconductor physics, materials science, microelectronics, analytical and numerical modelling, and high-performance computing. At the design stage, the systematic two-track approach was taken with the aim of attaining its submicron sensitivity: Firstly, the novel parametric method, devised for system-wide full optimisation, led to a considerable increase in detector’s total solid angle (0.9 steradian), or integrated field-of-view (~3000 deg2), thus, in turn, yielding a substantial enhancement of its photon-detection efficiency. Secondly, the minimisation of all types of limiting noise sources identified resulted in a boost to detector’s signal-to-noise ratio, thereby achieving its targeted range of sensitivity. The subsequent synchrotron-radiation experiment with this X-ray detector demonstrated its capability to respond to 8-keV photon beams with 600-nanometre sensitivity. This Article reports on the innovative and effective design methods, formulated for systematising the process of custom-building ultrasensitive photodetectors, and future directions.

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“…Compared to AC coupling, the non-linear response of the BLH can minimize baseline shifting at high event-rates. Such a BLH was successfully implemented in several different application-specific integrated circuits (ASICs) [5]–[11]. …”

Section: Introductionmentioning

confidence: 99%

Stability of the Baseline Holder in Readout Circuits for Radiation Detectors

Chen

Cui

O’Connor

et al. 2016

IEEE Trans. Nucl. Sci.

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Baseline holder (BLH) circuits are used widely to stabilize the analog output of application-specific integrated circuits (ASICs) for high-count-rate applications. The careful design of BLH circuits is vital to the overall stability of the analog-signal-processing chain in ASICs. Recently, we observed self-triggered fluctuations in an ASIC in which the shaping circuits have a BLH circuit in the feedback loop. In fact, further investigations showed that methods of enhancing small-signal stabilities cause an even worse situation. To resolve this problem, we used large-signal analyses to study the circuit’s stability. We found that a relatively small gain for the error amplifier and a small current in the non-linear stage of the BLH are required to enhance stability in large-signal analysis, which will compromise the properties of the BLH. These findings were verified by SPICE simulations. In this paper, we present our detailed analysis of the BLH circuits, and propose an improved version of them that have only minimal self-triggered fluctuations. We summarize the design considerations both for the stability and the properties of the BLH circuits.

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ASIC with Multiple Energy Discrimination for High-Rate Photon Counting Applications

Cited by 7 publications

References 21 publications

Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application

Exploring light confinement in laser-processed LYSO:Ce for photon counting CT application

Customisable X-ray fluorescence photodetector with submicron sensitivity using a ring array of silicon p-i-n diodes

Stability of the Baseline Holder in Readout Circuits for Radiation Detectors

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