High speed X-ray imaging camera using a structured CsI(Tl) scintillator

Abstract

New third generation X-ray sources such as the Advanced Photon Source have created a need for a detector that can provide multiple frames of detailed X-ray images on the millisecond time scale. Such detectors will prove invaluable in applications such as time-resolved X-ray diffraction, X-ray microtomography, as well as materials science applications like polymer processing. Currently, detectors capable of acquiring high resolution X-ray images at such high speed do not exist, thus limiting progress in many of these important areas of research. To address these needs we have developed a prototype fast X-ray imaging system, using a structured CsI(Tl) scintillator coupled to a fast-frame 1 K/spl times/1 K CCD. The system has been successfully employed to capture 1024/spl times/64 pixel X-ray images at a rate of 1000 frames per second (fps) with a 12 bit dynamic range. The system exceeds the capabilities of the current high speed X-ray imaging systems which typically operate at the rate of 30 fps. Fabrication of a large area detector is currently underway, using a microstructured CsI(Tl) scintillator coupled to a fast-frame CCD with a 3:1 fiberoptic taper. The camera will operate in a burst mode, acquiring 8 1 K/spl times/1 K images at rates up to 1000 frames per second with 12 bit dynamic range. Higher image capture speeds can be accomplished by reducing the image area. This paper discusses the specific characteristics of the CsI(Tl) screens, experimental details of the prototype and the new design for the large area detector being developed specifically for time-resolved X-ray diffraction experiments in structural biology.