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，以及相应地不断增长的、对时间分辨应用的苛刻需求，以及当前成像方式的局限性，对于研究人员和设备制造商来说，开发用于X射线成像中的光子计数的创新探测器技术的必要性已经变得显而易见。这种理想的新一代探测器必须提供经济实惠的读取噪声和暗噪声无噪声操作，以及准确、灵活的能量识别，以及尽可能高的X射线动态范围。此外，重要的质量包括在广泛的X射线能量范围内的高量子效率，以及用于高速应用的快速、可重复的读出。虽然光子计数的好处是巨大的，但挑战也是巨大的，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，我们建议开发一种用于光子计数数字X射线成像系统的新颖且经济实惠的高分辨率探测器。该模块将包括一个特别设计的CMOS数字像素传感器(DPS)，与一个低成本、像素化的闪烁体相结合，该闪烁体的厚度适合高效率地吸收同步辐射X射线。第一阶段研究的目标是证明开发用于同步加速器应用的这种探测器的可行性。具体地说，我们将开发技术来制造具有所需特性的新闪烁体，并将该传感器与新开发的cmos读数集成以形成原型探测器。这样生产的探测器将在我们的实验室以及阿贡国家实验室的高级光子源(APS)光束线上进行彻底的评估，以确定其灵敏度、分辨率和操作速度。除了对生物系统进行关键的时间分辨X射线衍射和散射研究外，该探测器还将在医学成像、高速计算机层析成像(CT)、无损检测和基础物理研究的许多领域得到广泛应用。由于其高性能、紧凑性和非常低的成本，建议的探测器将非常适合于从行李扫描到生物制剂检测的国土安全应用，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.