Low Cost Photon Counting Detector for Synchrotron Applications

认识到同步加速器源提供越来越高的光子通量的能力，以及相应的对时间分辨应用日益增长的苛刻需求，以及当前成像方式的局限性，研究人员和设备制造商都明显需要开发用于x射线成像中光子计数的创新探测器技术。这种理想的新一代探测器必须提供经济的无读噪声和暗噪声操作，准确，灵活的能量识别，以及尽可能高的x射线动态范围。另外重要的品质包括高量子效率在宽范围的x射线能量，和快速，可重复读出高速应用。虽然光子计数的好处是巨大的，但挑战也很重要，目前的系统都没有有效地解决这些挑战。为了满足这些需求，我们建议开发一种新颖且具有成本效益的高分辨率探测器，用于光子计数数字x射线成像系统。该模块将包括一个专门设计的CMOS数字像素传感器（DPS），以及一个低成本的精细像素化闪烁体，其厚度适合高效吸收同步加速器x射线。第一阶段研究的目标是证明为同步加速器应用开发这种探测器的可行性。具体来说，我们将开发技术来制造具有所需性能的新闪烁体，并将该传感器和新开发的CMOS读出器集成在一起，形成一个原型探测器。由此产生的探测器将在我们的实验室以及阿贡国家实验室的先进光子源（APS）光束线进行全面评估，以确定其灵敏度，分辨率和运行速度。除了进行生物系统的关键时间分辨x射线衍射和散射研究外，该探测器将广泛应用于医学成像，高速计算机断层扫描（CT），无损检测和基础物理研究的许多领域。由于其高性能，紧凑的性质和非常低的成本，该探测器将非常适合国土安全应用，从行李扫描到生物制剂的检测，而不会污染探测器系统。

Recognizing the ability of synchrotron sources to deliver increasingly higher photon fluxes and the correspondingly rising, demanding needs of time-resolved applications, along with the limitations of current imaging modalities, the need for the development of an innovative detector technology for photon counting in X-ray imaging has become apparent to researchers and equipment manufacturers alike. This desired new generation of detectors must provide economical read noise- and dark noise-free operation and accurate, flexible energy discrimination, plus the highest possible X-ray dynamic range. Additionally important qualities include high quantum efficiency over wide range of X-ray energies, and fast, repeatable readout for high-speed applications. While the benefits of photon counting are substantial, the challenges are also significant, and none of the current systems effectively address these challenges. To address these needs, we propose to develop a novel and cost-effective, high-resolution detector for use in photon-counting digital X-ray imaging systems. The module will consist of a specially designed CMOS Digital Pixel Sensor (DPS), coupled to a low-cost finely pixelated scintillator of thickness appropriate to absorb synchrotron X-rays with high efficiency. The goal of the Phase I research is to demonstrate the feasibility of developing such a detector for synchrotron applications. Specifically, we will develop technologies to fabricate the new scintillator with the desired properties and integrate this sensor and a newly developed CMOS readout to form a prototype detector. The detector thus produced will be thoroughly evaluated in our laboratory as well as at the Advanced Photon Source (APS) beamline at Argonne National Laboratory to establish its sensitivity, resolution, and speed of operation. Besides performing critical time-resolved X-ray diffraction and scattering studies of biological systems, this detector will find widespread use in many areas of medical imaging, high-speed computed tomography (CT), non-destructive testing, and basic physics research. Due to its high performance, compact nature and very low cost, the proposed detector will be ideally suited for homeland security applications ranging from baggage scanning to the detection of biological agents without contaminating the detector system.