Hybrid Pixel Detectors for gamma/X-ray imaging

[摘要] Hybrid pixel detectors are made by direct converting high-Z semi-insulating single crystalline material coupled to complementary-metal-oxide semiconductor (CMOS) readout electronics. They are attractive because direct conversion exterminates all the problems of spatial localization related to light diffusion, energy resolution, is far superior from the combination of scintillation crystals and photomultipliers and lithography can be used to pattern electrodes with very fine pitch. We are developing 2-D pixel CMOS ASICs, connect them to pixilated CdTe crystals with the flip chip and bump bonding method and characterize the hybrids. We have designed a series of circuits, whose latest member consists of a 50×25 pixel array with 400um pitch and an embedded controller. In every pixel a full spectroscopic channel with time tagging information has been implemented. The detectors are targeting Compton scatter imaging and they can be used for coded aperture imaging too. Hybridization using CMOS can overcome the limit put on pixel circuit complexity by the use of thin film transistors (TFT) in large flat panels. Hybrid active pixel sensors are used in dental imaging and other applications (e.g. industrial CT etc.). Thus X-ray imaging can benefit from the work done on dynamic range enhancement methods developed initially for visible and infrared CMOS pixel sensors. A 2-D CMOS ASIC with 100um pixel pitch to demonstrate the feasibility of such methods in the context of X-ray imaging has been designed.

[发布机构] Aircarft Engineering Department, Technological Educational Institute of Sterea, Ellada, Greece^1;Ajat Oy Ltd., Finland^2;Broadcom Corporation, United States^3;Department of Electrical and Computer Engineering, National Technical University of Athens, Greece^4;Institute of Nuclear Physics, National Center for Scientific Research Demokritos, Greece^5

[效力级别] 医药卫生 [学科分类] 卫生学

[关键词] Coded aperture imaging;Complementary metal oxide semiconductors;Compton scatter imaging;Embedded controllers;Hybrid pixel detectors;Scintillation crystals;Single-crystalline materials;Spectroscopic channels