Scintillating films are usually used to improve the sensitivity of CCD-based X-ray imaging detectors. For an optimal spatial resolution and detection efficiency, a tradeoff has to be made on the film thickness. However, these scintillating layers can also be structured to provide a pixellated screen. In this paper, the study of CsI(Tl)-filled pore arrays is reported. The pores are first etched in silicon, then oxidized and finally filled with CsI(Tl) to form scintillating waveguides. The dependence of the detector sensitivity on pore depth, varied from 40 to 400 µm here, follows rather well theoretical predictions. Most of the detectors produced in this work have a detective quantum efficiency of the incoming X-ray photons of about 25%; however, one detector shows that higher efficiency can be achieved. The comparison of its efficiency to a 1-mm thick CsI(Tl) crystal indicates that light collection efficiency in the guides may approach what is theoretically possible. Imaging capabilities of the detectors are demonstrated.
VR-Physics