Low Cost Photon Counting Detector for Synchrotron Applications

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.