Direct Deposition of Microcolumnar Scintillator on CMOS SSPM Array: Toward a Photon Counting Detector for X-Ray∕Gamma Ray Imaging

Prekas, G.; Breen, M.; Sabet, Hamid; Bhandari, Harish B.; Derderian, G.; Robertson, F.; Stapels, Christopher J.; Christian, James F.; Cool, Steven; Nagarkar, Vivek V.

doi:10.1063/1.3665323

Cited by 3 publications

(3 citation statements)

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“…The conceptual detector outlined here is different from the scintillator based EIDs used in conventional CT, in that EIDs are typically based on Cadmium Tungstate (CWO) which has comparable stopping power to LYSO:Ce, but much longer decay time, making them unsuitable for operation in pulse mode given the high count rates in clinical CT. While there has been previous efforts in developing microcolumnar scintillator detectors suitable for photon counting CT (Prekas et al 2011, Sabet et al 2012b, these are associated with limitations in count rate and achievable detector thickness which results in low dose efficiency. Furthermore, these microcolumnar detectors were based on CsI:Tl, which similarly to CWO has a long decay time (Lecoq 2016).…”

Section: Discussionmentioning

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: Discussionmentioning

confidence: 99%

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

et al. 2019

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“…The experimental methods, materials and samples used for studying the performance of the detector array have been described in detail elsewhere [27,28]. In this paper we will discuss the highlights and summarize the advantages and disadvantages that rrticrocolumnar films possess over the traditionally used monolithic and/or mechanically structured (pixelated) scintillators, when coupled to an imaging photodetector -in this case, a solid state photomultiplier.…”

Section: A Detector Array; Csi:tl Directly Coupled To Solid State Phmentioning

confidence: 99%

Direct and indirect detectors for X-ray photon counting systems

Prekas

Sabet

Bhandari

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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Most currently available X-ray or gamma ray imaging detectors are based on energy integration over a certain period of time. We have been developing X-ray and gamma ray detectors based on the photon counting (with energy determination) concept using both direct and indirect radiation conversion, together with associated application-specific integrated circuits (ASICs). As an alternative to our ASIC design approach, we are also exploiting the potential of state-of-the-art silicon photomultipliers (SiPMs) and discrete electronics. In this paper we discuss the advantages and disadvantages of these two approaches and we report our latest results on our ASIC design efforts and our achievements on SiPMlCsI:TI detector configurations. We will also discuss the potential uses and advantages that each offers to applications in medicine, imaging, homeland security and industry.

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“…Furthermore, with emerging photodetector technologies such as silicon photomultipliers (SiPMs), development of compact and cost-effective imaging probes are now possible. In this regard, we have been developing detectors using these new photodetectors and combining them with RMD's microcolumnar scintillator technology [20][21][22]. We adapted these technologies to develop high performance detectors for intra-operative imaging -sensitive probe called Imaging Beta probe (IPB).…”

Section: Introductionmentioning

confidence: 99%