Microsecond time-resolved 2D X-ray imaging

A method is presented which allows to take two-dimensional X-ray images of repetitive processes with recording times in the sub-microsecond range. Various measurements have been performed with a recently introduced novel two-dimensional single photon counter which has been slightly modified in order to determine the exact arrival time of each detected photon. For this purpose a special clock signal is synchronized with the process and is digitized contemporaneously with each event. This technique can be applied even with rate limited detectors and low flux sources, since-unlike in conventional methods, where chopped beams or gated read out electronics are used-all photons are used for the image formation. For the measurements, rapidly moving mechanical systems and conventional X-ray sources have been used, reaching time resolutions of some 10 mus. The technique presellted here opens a variety of new biological, medical and industrial applications which will be discussed. As a first application example, three dimensional tomographic reconstructions of rapidly rotating objects (4000 turns/min) are presented. (C) 2001 Elsevier Science B.V. All rights reserved.