Engineering a High Resolution Scintillator for Next-Generation High Frame Rate Detectors

Recent improvements in synchrotron radiation sources have generated an urgent need for high-performance X-ray detectors. While new imaging devices have been developed that employ high-performance CCD sensors, what is currently lacking in these detectors is an adequate X-ray-to-light converter that will provide high performance in terms of spatial resolution, efficiency and, perhaps most importantly, fast decay of the scintillation light in order to allow the high-speed image acquisition that is necessary for performing dynamic or time- resolved experiments. To address these issues, we propose to develop and manufacture a novel high-speed scintillator, through the band gap engineering of the well-known microcolumnar CsI:Tl screens that are common in advanced X-ray imaging systems. The enhanced, co-doped CsI:Tl will provide all of the benefits of conventional CsI:Tl, but with a 10- to 100-fold reduction in afterglow and negligible hysteresis. The microcolumnar form of the co-doped CsI:Tl scintillator will combine high X-ray absorption, high spatial resolution, and negligible afterglow and hysteresis. The proposed scintillator will enable the realization of the high-speed, large-area, high- resolution detectors needed for important time-resolved X-ray diffraction and other studies. During the Phase I research, we demonstrated the feasibility of developing a manufacturing method to produce co-doped CsI:Tl films that consistently exhibit both low afterglow and superior spatial resolution ranging from several to tens of microns, depending on thickness. These films were characterized in detail in terms of both scintillation properties and imaging performance by integrating them into the latest high-performance camera developed by our commercial collaborator and evaluated at the BioCAT beam line at the Advanced Photon Source (Argonne National Laboratory, Chicago). We have also performed imaging experiments at 1000 frames per second that demonstrate the low afterglow and bright emissions of the films. During the proposed Phase II research, we will undertake efforts to successfully optimize the Phase I process in order to produce and market these screens through our own resources and in collaboration with our commercial partners. The goal of the Phase II will be to produce films up to 2020 cm2 in area, with high light output, low afterglow, and high spatial resolution, to advance the performance of next-generation high frame rate detectors. By working closely with our commercial partners during the Phase II, we will establish a clear path to transition the Phase II research into a Phase III customer-oriented product. Commercial Applications and Other Benefits: Applications for the enhanced scintillator developed here are many, and range from macromolecular crystallography to medical imaging, and from nondestructive testing to polymer research. Due to the extraordinary properties of this scintillator, it will have widespread use in many important synchrotron-based applications.