TIME-RESOLVED SMALL-ANGLE AND WIDE-ANGLE X-RAY-SCATTERING APPARATUS USING THE IMAGING PLATE AS A 2-DIMENSIONAL DETECTOR

We report an application of the imaging plate, which contains phosphor crystals photostimulable by an X-ray beam, as a two-dimensional (2D) detector for time-resolved small-angle X-ray scattering (SAXS) and wid e-angle X-ray diffraction (WAXD) studies especially designed for use w ith a rotating anode X-ray generator as an incident X-ray beam source. The detector constructed has the shape of an octahedral cylinder, and to each face is attached an imaging plate of 200 mm width and 100 mm height. Each plate consists of 800 x 1600 pixels with an area of 125 x 125 mu m(2)/pixel. Time-resolved data acquisition of SAXS and WAXD pa tterns on the 2D detector is performed by changing the plate face with lime either by a rotation of the drum or by shifting a face of the pl ate in the drum with respect to the incident beam. The detection (whic h consists of writing and reading) of scattered X-ray intensity distri butions with the plates as well as erasure of the scattering patterns stored on the plates can be continuously performed by rotating the dru m. The reading rate for the scattering patterns recorded onto the plat e is 25 mu s/pixel or 300 s/plate. The time required for changing the plate face from one to another by rotating the drum is 2 s, which corr esponds to a minimum dead lime for the time-resolved study with an eff ective area of 100 x 200 mm(2). When necessary, especially to shorten the dead time for the measurements, each plate can be further divided into N sections by shifting the drum with respect to the incident beam , the time required for the shifting being 25 ms/mm. Thus when the pla te of 200 x 100 mm(2) is divided into sections of (200/N) x 100 mm(2), the minimum dead time is reduced to 25 x (200/N) ms.