A New Large Radius Imaging Plate Camera System for the Diffractometer in BL15XU of SPring-8 for High-resolution and High-throughput Powder Diffraction

WEBRAM / SPring8, National Institute for Materials Science* SPring-8 Service Co. Ltd.,**
â—‹Masahiko Tanaka* Yoshio Katsuya** Daisuke Nomoto**

A new large radius imaging plate (IP) system for high-resolution and high-throughput powder X-ray diffraction has been developed for the 2-axis diffractometer at BL-15XU, which is an undulator beamline of SPring-8. An IP cassette that has a cylinder surface shape with a radius of 954.9mm is set on the 2-theta arm of the diffractometer normal to the incident X-ray. This system has Debye-Scherrer geometry and the diffracted X-rays from the sample filled into glass capillary placed at the center of the diffractometer are recorded on the IP. The IP size is 200*400mm and an IP covers 24 degrees of the 2-theta. To collect one data set, several exposures are necessary while changing the 2-theta and overlapping the 2-theta ranges. The separately collected data are translated to 2-theta-intensity format and are connected by comparing the peak intensity included in the overlapped area. The diffraction data is read out by Fuji Film BAS-2500 with pixel resolution of 50 micrometers. One pixel equals 0.003 degrees of the 2-theta. The exposure time is less than 120 seconds for most samples and the readout time is about 3 minutes, thus the total measurement time for one powder diffraction pattern is less than 20 minutes. The 2-theta errors caused by inconsistency of the sample position and rotation center of the 2-theta are corrected by an external standard. The angular resolution of this system was evaluated by comparing the FWHM of 111 reflection of NBS-Si. The observed FWHM was 0.011 degrees and the value is smaller than that of the powder diffractometer with Ge(111) analyzer at a bending magnet beamline of 2nd generation synchrotron. This new system has achieved twenty-times faster powder diffraction improving the high resolution of current synchrotron powder diffractometer.