Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507827
A. Groll, D. Anders, R. Stanford-Hill, S. Gambhir, C. Levin
This work presents the initial imaging studies for a large volume CZT preclinical PET system. Two full heads of the final four-headed box-shaped system have been constructed with each head composed of 24 CZT crystals; each crystal is of size 40 × 40 × 5 mm3 with sets of orthogonal anode and cathode electrode strips deposited on opposite sides of the crystals. Crystals are paired to form modules with an anode-cathode-cathode-anode configuration. Each CZT crystal has 39 anode strips and 38 electrodes. Anode strips are 100 µm wide with a 1 mm pitch, and steering electrode are 400 µm wide. The cathode side of the detector module is composed of 8 strips which are 4.9 mm wide with a pitch of 5 mm. Photons enter the crystal in an “edge-on” orientation and pass through the 5×40 mm2 edge, which results in a detection efficiency equivalent to that of 2 cm of LSO scintillator. The readout of the cathode and anode strips are supported by custom front end electronics designed around a readout ASIC. This configuration has 3,456 readout channels with an effective 1,872 anode channels and 384 cathode channels. In this work, we imaged a multi-well multi-isotope phantom composed of various activities of FDG and Co-55 ranging from 50 to 100 µCi. The CNR of a 100 µCi FDG well against background was measured to 33.48.
{"title":"Imaging Studies from a Large Volume High Resolution Cadmium Zinc Telluride Preclinical PET System","authors":"A. Groll, D. Anders, R. Stanford-Hill, S. Gambhir, C. Levin","doi":"10.1109/NSS/MIC42677.2020.9507827","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507827","url":null,"abstract":"This work presents the initial imaging studies for a large volume CZT preclinical PET system. Two full heads of the final four-headed box-shaped system have been constructed with each head composed of 24 CZT crystals; each crystal is of size 40 × 40 × 5 mm3 with sets of orthogonal anode and cathode electrode strips deposited on opposite sides of the crystals. Crystals are paired to form modules with an anode-cathode-cathode-anode configuration. Each CZT crystal has 39 anode strips and 38 electrodes. Anode strips are 100 µm wide with a 1 mm pitch, and steering electrode are 400 µm wide. The cathode side of the detector module is composed of 8 strips which are 4.9 mm wide with a pitch of 5 mm. Photons enter the crystal in an “edge-on” orientation and pass through the 5×40 mm2 edge, which results in a detection efficiency equivalent to that of 2 cm of LSO scintillator. The readout of the cathode and anode strips are supported by custom front end electronics designed around a readout ASIC. This configuration has 3,456 readout channels with an effective 1,872 anode channels and 384 cathode channels. In this work, we imaged a multi-well multi-isotope phantom composed of various activities of FDG and Co-55 ranging from 50 to 100 µCi. The CNR of a 100 µCi FDG well against background was measured to 33.48.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"88 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86054060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9508050
F. Carrió, J. Bernabeu, V. Cindro, A. Gorišek
The ATLAS Phase-II Upgrade will replace the Inner detector with a new all-silicon Inner Tracker (ITk) to accommodate the radiation damage and track density expected at the High-Luminosity LHC (HL-LHC). The all-silicon ITk for the HL-LHC consists of a pixel detector with 5 barrel layers and multiple forward disks at a small radius, and a strip tracking detector at the outermost part with 4 barrel layers and 6-end-cap disks on each side. This contribution presents the design of the flexible circuit (bus tape) for the local support structures of the end-cap region of the strip detector, called petals. The bus tapes provide the electrical interface to common services for all the on-board subsystems including power, control and data interfaces. Connections to external services outside of the petals are carried out through the End-of-Structure (EoS) card using optical fibres and copper wires. The bus tapes are manufactured as a 2-layer printed circuit board using polyimide and adhesive Kapton films, with a total thickness of 185 μm and a total length of 60 cm. The layout design has been focused on achieving good signal and power integrity while keeping low mass and low thermal resistance. A total of 768 end-cap bus tapes are needed between 2021 and 2022 for the production of 384 petals with 6,912 modules, where each end-cap disk will consist of 32 petals.
{"title":"Design of Bus Tapes for the ATLAS Strip End-Cap at the HL-LHC","authors":"F. Carrió, J. Bernabeu, V. Cindro, A. Gorišek","doi":"10.1109/NSS/MIC42677.2020.9508050","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9508050","url":null,"abstract":"The ATLAS Phase-II Upgrade will replace the Inner detector with a new all-silicon Inner Tracker (ITk) to accommodate the radiation damage and track density expected at the High-Luminosity LHC (HL-LHC). The all-silicon ITk for the HL-LHC consists of a pixel detector with 5 barrel layers and multiple forward disks at a small radius, and a strip tracking detector at the outermost part with 4 barrel layers and 6-end-cap disks on each side. This contribution presents the design of the flexible circuit (bus tape) for the local support structures of the end-cap region of the strip detector, called petals. The bus tapes provide the electrical interface to common services for all the on-board subsystems including power, control and data interfaces. Connections to external services outside of the petals are carried out through the End-of-Structure (EoS) card using optical fibres and copper wires. The bus tapes are manufactured as a 2-layer printed circuit board using polyimide and adhesive Kapton films, with a total thickness of 185 μm and a total length of 60 cm. The layout design has been focused on achieving good signal and power integrity while keeping low mass and low thermal resistance. A total of 768 end-cap bus tapes are needed between 2021 and 2022 for the production of 384 petals with 6,912 modules, where each end-cap disk will consist of 32 petals.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"3 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81357520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507754
D. Doering, M. Kwiatkowski, Umanath Kamath, C. Tamma, L. Rota, L. Ruckman, R. Herbst, B. Reese, P. Caragiulo, G. Blaj, C. Kenney, G. Haller, A. Dragone
LCLS-II, a Free Electron Laser (FEL) X-ray light source, started operations at SLAC National lab in 2020. This new machine will produce X-ray pulses with a repetition rate up to 1,000,000 times per second. To take advantage of its high pulse rate, detectors and readout systems that can operate at the same frequency and cope with the generated data volumes are being developed. In this paper, we present the readout system for the first generation of ePixHR high rate detectors including the first readout ASIC, namely, ePixHR10k, the first prototype of this family. This system aims at sustaining readout rates higher than 5,000 frames per second for the matrix of the ePixHR10k sensor/ASIC module (288 rows x 384 columns and 2 bytes per pixel). The proposed electronic system uses an FPGA to perform data capture and transmission to a host computer. The firmware is developed using a custom public library called SURF where building blocks such as ASIC register access, high speed communication links, protocols for data stream, and register configuration exist. The user interface uses a companion framework called ROGUE, which implements the software modules for the elements that exist in SURF. Initial results from X-ray tests using Fe55 source are presented.
{"title":"Readout System for ePixHR X-ray Detectors: A Framework and Case Study","authors":"D. Doering, M. Kwiatkowski, Umanath Kamath, C. Tamma, L. Rota, L. Ruckman, R. Herbst, B. Reese, P. Caragiulo, G. Blaj, C. Kenney, G. Haller, A. Dragone","doi":"10.1109/NSS/MIC42677.2020.9507754","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507754","url":null,"abstract":"LCLS-II, a Free Electron Laser (FEL) X-ray light source, started operations at SLAC National lab in 2020. This new machine will produce X-ray pulses with a repetition rate up to 1,000,000 times per second. To take advantage of its high pulse rate, detectors and readout systems that can operate at the same frequency and cope with the generated data volumes are being developed. In this paper, we present the readout system for the first generation of ePixHR high rate detectors including the first readout ASIC, namely, ePixHR10k, the first prototype of this family. This system aims at sustaining readout rates higher than 5,000 frames per second for the matrix of the ePixHR10k sensor/ASIC module (288 rows x 384 columns and 2 bytes per pixel). The proposed electronic system uses an FPGA to perform data capture and transmission to a host computer. The firmware is developed using a custom public library called SURF where building blocks such as ASIC register access, high speed communication links, protocols for data stream, and register configuration exist. The user interface uses a companion framework called ROGUE, which implements the software modules for the elements that exist in SURF. Initial results from X-ray tests using Fe55 source are presented.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"13 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85158825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507955
Y. Liu, X. Xiao, Z. Zhang, W. Zhou, X. Wang, L. Wei
Compton scatter imaging (CSI) is a useful nondestructive testing technique because of its flexible detection layout and high sensitivity to low-Z but high-density materials such as organics. However, previous CSI methods are limited by their low use of X-rays. Recently, we have devised a novel method called coded aperture push-broom CSI (CAPCSI) to improve the use of X-rays. In this work, we will present our progress on large field-of-view CAPCSI. A fan-beam of X-rays scans objects line-by-line and then the X-rays are scattered backward to two linear array detectors. Each detector consists of 144 scintillators, 96 Silicon photo-multipliers, and a 32-channel readout circuit array. In front of the two detectors, a mask and an anti-mask are placed individually to filter the backscattered X-rays. The coding sequences of the mask and the anti-mask are just opposite so that two complementary images could be recorded simultaneously. After averaging the two images, we finally obtain a better image for low-dose imaging.
{"title":"Progress on large field-of-view coded aperture push-broom Compton scatter imaging","authors":"Y. Liu, X. Xiao, Z. Zhang, W. Zhou, X. Wang, L. Wei","doi":"10.1109/NSS/MIC42677.2020.9507955","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507955","url":null,"abstract":"Compton scatter imaging (CSI) is a useful nondestructive testing technique because of its flexible detection layout and high sensitivity to low-Z but high-density materials such as organics. However, previous CSI methods are limited by their low use of X-rays. Recently, we have devised a novel method called coded aperture push-broom CSI (CAPCSI) to improve the use of X-rays. In this work, we will present our progress on large field-of-view CAPCSI. A fan-beam of X-rays scans objects line-by-line and then the X-rays are scattered backward to two linear array detectors. Each detector consists of 144 scintillators, 96 Silicon photo-multipliers, and a 32-channel readout circuit array. In front of the two detectors, a mask and an anti-mask are placed individually to filter the backscattered X-rays. The coding sequences of the mask and the anti-mask are just opposite so that two complementary images could be recorded simultaneously. After averaging the two images, we finally obtain a better image for low-dose imaging.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"42 1","pages":"1-2"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90592546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507967
Seowung Leem, Byeong-Yeol Yu, H. Cha, Kyeyoung Cho, R. Miyaoka, Cheolung Kang, Jongmyoung Lee, Seungbin Bae, Hakjae Lee, Kisung Lee
Crystal area segmentation is one of the critical procedures for decoding the detector module coupled with scintillation crystal. However, the blurring effect makes the decoding procedure challenging. For precise decoding, we propose a crystal area segmentation method based on convolutional neural network (CNN). The method is divided into training stage and evaluation stage. In the training stage, data set was extracted from five flood maps in blocks. These blocks went over preprocessing with bandpass filter (BPF) and thresholding. Then the processed blocks were used to train and test the CNN. In evaluation stage, flood map from 2 positron emission tomography (PET) scanners were tested. The method showed 99.5% and 99.4% of peak detection accuracy for each test samples while existing method achieved 91.1% and 95.4%. The proposed algorithm detected center peaks almost perfectly and improved detectability of boundary peaks. Also, the whole decoding process was done in short amount of time. However, the algorithm proposed in this paper only considered the spatial information of the peaks in flood map. In further studies we will develop improved algorithm with using both spatial and energy information to develop more precise and practical decoding algorithm.
{"title":"Crystal Area Segmentation for a Scintillation Detector based on Convolutional Neural Network","authors":"Seowung Leem, Byeong-Yeol Yu, H. Cha, Kyeyoung Cho, R. Miyaoka, Cheolung Kang, Jongmyoung Lee, Seungbin Bae, Hakjae Lee, Kisung Lee","doi":"10.1109/NSS/MIC42677.2020.9507967","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507967","url":null,"abstract":"Crystal area segmentation is one of the critical procedures for decoding the detector module coupled with scintillation crystal. However, the blurring effect makes the decoding procedure challenging. For precise decoding, we propose a crystal area segmentation method based on convolutional neural network (CNN). The method is divided into training stage and evaluation stage. In the training stage, data set was extracted from five flood maps in blocks. These blocks went over preprocessing with bandpass filter (BPF) and thresholding. Then the processed blocks were used to train and test the CNN. In evaluation stage, flood map from 2 positron emission tomography (PET) scanners were tested. The method showed 99.5% and 99.4% of peak detection accuracy for each test samples while existing method achieved 91.1% and 95.4%. The proposed algorithm detected center peaks almost perfectly and improved detectability of boundary peaks. Also, the whole decoding process was done in short amount of time. However, the algorithm proposed in this paper only considered the spatial information of the peaks in flood map. In further studies we will develop improved algorithm with using both spatial and energy information to develop more precise and practical decoding algorithm.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"12 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89693568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507786
I. D'Adda, M. Carminati, A. Cerrato, A. Morahan, K. Erlandsson, B. Hutton, C. Fiorini
The estimation of the Depth-of-Interaction (DOI) of detected gamma photons is especially challenging for thick scintillators, yet relevant for moderately thin ones (8 mm CsI(Tl) in our case) employed in nuclear imaging. In SPECT, in particular using pinhole or slit-slat collimation, the parallax error produced by photons passing through the collimator holes, with trajectories non orthogonal to the crystal surface, can be reduced by including the DOI information into the tomographic reconstruction. We present an algorithm based on maximum likelihood that classifies into 4 layers the events absorbed in the scintillator. A novel initialization signal (a ring footprint surrounding the channel detecting the highest intensity) is proposed, only requiring a flood field irradiation as training. The algorithm is experimentally validated by means of a tilted collimated beam on a single camera. The DOI information will be applied in a stationary clinical MRI-compatible SPECT insert which is composed of 20 identical modules mounted in a partial ring.
估计探测到的伽马光子的相互作用深度(DOI)对于厚闪烁体来说尤其具有挑战性，但对于核成像中使用的中等厚度的闪烁体(在我们的情况下为8 mm CsI(Tl))是相关的。在SPECT中，特别是使用针孔或缝条准直时，光子通过准直器孔产生的视差误差可以通过将DOI信息包含到层析重建中来减小，其轨迹与晶体表面不正交。我们提出了一种基于极大似然的算法，将闪烁体吸收的事件划分为4层。提出了一种新的初始化信号(在检测最高强度的通道周围的环形足迹)，只需要洪水场照射作为训练。该算法在单相机上进行了倾斜准直光束的实验验证。DOI信息将应用于固定的临床mri兼容SPECT插入物，该插入物由安装在部分环中的20个相同模块组成。
{"title":"DOI Estimation for a Clinical MRI-Compatible SPECT Insert","authors":"I. D'Adda, M. Carminati, A. Cerrato, A. Morahan, K. Erlandsson, B. Hutton, C. Fiorini","doi":"10.1109/NSS/MIC42677.2020.9507786","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507786","url":null,"abstract":"The estimation of the Depth-of-Interaction (DOI) of detected gamma photons is especially challenging for thick scintillators, yet relevant for moderately thin ones (8 mm CsI(Tl) in our case) employed in nuclear imaging. In SPECT, in particular using pinhole or slit-slat collimation, the parallax error produced by photons passing through the collimator holes, with trajectories non orthogonal to the crystal surface, can be reduced by including the DOI information into the tomographic reconstruction. We present an algorithm based on maximum likelihood that classifies into 4 layers the events absorbed in the scintillator. A novel initialization signal (a ring footprint surrounding the channel detecting the highest intensity) is proposed, only requiring a flood field irradiation as training. The algorithm is experimentally validated by means of a tilted collimated beam on a single camera. The DOI information will be applied in a stationary clinical MRI-compatible SPECT insert which is composed of 20 identical modules mounted in a partial ring.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"19 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84439396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507957
L. Brusaferri, Elise Emond, A. Bousse, R. Twyman, D. Atkinson, B. Hutton, S. Arridge, K. Thielemans
Several groups have considered the option of using multiple-energy window emission data to improve reconstruction accuracy for PET/MR imaging. However, the feasibility of this approach has only been studied with analytic simulations. To be able to handle realistic measurements a remaining challenge is related to the detection efficiencies (“normalisation”) for the different energy windows, which likely differ for scattered and unscattered events given the heterogeneity of photon energies, angles of incidence, and points of origination. In addition, the lower energy windows will potentially contain events that have been affected by scatter in the detector. This manuscript investigates the problem of estimating the normalisation factors for PET data acquired from multiple energy windows.
{"title":"Normalisation Factor Estimation in non-TOF 3D PET from Multiple-Energy Window Data","authors":"L. Brusaferri, Elise Emond, A. Bousse, R. Twyman, D. Atkinson, B. Hutton, S. Arridge, K. Thielemans","doi":"10.1109/NSS/MIC42677.2020.9507957","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507957","url":null,"abstract":"Several groups have considered the option of using multiple-energy window emission data to improve reconstruction accuracy for PET/MR imaging. However, the feasibility of this approach has only been studied with analytic simulations. To be able to handle realistic measurements a remaining challenge is related to the detection efficiencies (“normalisation”) for the different energy windows, which likely differ for scattered and unscattered events given the heterogeneity of photon energies, angles of incidence, and points of origination. In addition, the lower energy windows will potentially contain events that have been affected by scatter in the detector. This manuscript investigates the problem of estimating the normalisation factors for PET data acquired from multiple energy windows.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"55 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88264256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507740
J. Segal, C. Kenney, R. Patti, Benjamin Parpillon, Sangki Hong
Low Gain Avalanche Detectors (LGADs) have recently been studied for applications in high energy physics. They provide the advantages of built-in gain and fast read-out. However, radiation hardness remains a problem, reduced effective boron doping concentration (acceptor removal) after hadron irradiation that dramatically reduces LGAD gain. We propose a new LGAD process flow that allows for creation of a very steep boron profile in the multiplication region, reducing the fractional acceptor removal and resulting performance degradation. The new LGAD process flow requires a low temperature silicon-silicon wafer bonding process, which is currently under development. TCAD process simulations are used to demonstrate feasibility of the new structure, and TCAD device simulations are used to characterize LGAD performance before and after irradiation.
{"title":"New Radiation Tolerant LGAD for High Energy Physics","authors":"J. Segal, C. Kenney, R. Patti, Benjamin Parpillon, Sangki Hong","doi":"10.1109/NSS/MIC42677.2020.9507740","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507740","url":null,"abstract":"Low Gain Avalanche Detectors (LGADs) have recently been studied for applications in high energy physics. They provide the advantages of built-in gain and fast read-out. However, radiation hardness remains a problem, reduced effective boron doping concentration (acceptor removal) after hadron irradiation that dramatically reduces LGAD gain. We propose a new LGAD process flow that allows for creation of a very steep boron profile in the multiplication region, reducing the fractional acceptor removal and resulting performance degradation. The new LGAD process flow requires a low temperature silicon-silicon wafer bonding process, which is currently under development. TCAD process simulations are used to demonstrate feasibility of the new structure, and TCAD device simulations are used to characterize LGAD performance before and after irradiation.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"51 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87024741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507765
Xinyi Cheng, K. Hu, Dongxu Yang, Y. Shao
We report the development of a compact high-resolution detector for a positron emission tomography (PET) insert in small animal irradiator. The detector consists of 4 sub-detectors; each sub-detector consists of a 15×15 array of 1×1×20 mm3 LYSO scintillators with each array end coupled to an 8×8 array of 2×2 mm2 silicon photomultipliers for depth-of-interaction (DOI) measurement; all sides of scintillators were roughed with a 0.03 mm surface lapping for balanced detector performance. Based on row and column signal readout, only 64-ch electronics is required to process 512-ch output of each detector. A compact 96-ch electronics board was developed to measure the charge, timing, and position of each interaction and convert them into digital output pulses for further processing. The detector performance evaluation study shows an average ~26.3% energy resolution, ~3.2 ns coincidence timing resolution, and ~3.2 mm DOI resolution from all crystals. All scintillators are well identified. The maximum throughput of the detector is ~200 K events/s.
{"title":"Design and development of a compact high-resolution detector for PET insert in small animal irradiator","authors":"Xinyi Cheng, K. Hu, Dongxu Yang, Y. Shao","doi":"10.1109/NSS/MIC42677.2020.9507765","DOIUrl":"https://doi.org/10.1109/NSS/MIC42677.2020.9507765","url":null,"abstract":"We report the development of a compact high-resolution detector for a positron emission tomography (PET) insert in small animal irradiator. The detector consists of 4 sub-detectors; each sub-detector consists of a 15×15 array of 1×1×20 mm3 LYSO scintillators with each array end coupled to an 8×8 array of 2×2 mm2 silicon photomultipliers for depth-of-interaction (DOI) measurement; all sides of scintillators were roughed with a 0.03 mm surface lapping for balanced detector performance. Based on row and column signal readout, only 64-ch electronics is required to process 512-ch output of each detector. A compact 96-ch electronics board was developed to measure the charge, timing, and position of each interaction and convert them into digital output pulses for further processing. The detector performance evaluation study shows an average ~26.3% energy resolution, ~3.2 ns coincidence timing resolution, and ~3.2 mm DOI resolution from all crystals. All scintillators are well identified. The maximum throughput of the detector is ~200 K events/s.","PeriodicalId":6760,"journal":{"name":"2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC)","volume":"70 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2020-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86275418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-10-31DOI: 10.1109/NSS/MIC42677.2020.9507877
Jessica Charest, Ryan Tan, Bogdan Dryzhakov, Kate Higgins, Christopher Busch, Bin Hu, M. Ahmadi, E. Lukosi
This report several techniques are under investigation to improve the spectroscopic capability of methylammonium lead tribromide perovskite semiconductors (CH3NH3PbBr3, or MAPB). These techniques include birefringence level measurements used to evaluate the quality of the single crystals and increase fabrication success rate of radiation responsive crystals. In addition, several characterization techniques are performed on a partial cation-substitution of MAPB with lithium-6 to analyze the structure and surface properties of the single crystal produced. Finally, we will present the thermal neutron sensing results from a MAPB crystal substituted with lithium-6.
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