DATA-PROCESSING SYSTEM FOR X-RAY FIBER DI FFRACTION PATTERNS OBTAINEDBY USING AN IMAGING PLATE

A new system utilizing an Imaging Plate (IP) was used to take X-ray fi ber diagrams instead of the conventional photographic method. The IP h as a large effective area, wide dynamic range, and high sensitivity. P resented here is an interactive computer program system for processing fiber diffraction data obtained by the IP. The system runs on the gra phics workstation and it consists of three programs. The first program is to obtain the center of the diffraction pattern, the second one is to determine cell constants, and the third one is for intensity measu rement. It was assumed that the shape of reflections is an ellipse and the background intensity along the radial and azimuthal directions ch anges linearly. The integrated intensity was measured by accumulating an intensity at each pixel within the ellipse after subtracting the ba ckground intensity. This system was applied to the structural analysis of a poly[(4,4'-diphenylene) pyromellitimide] fiber. The agreement fa ctors with and without unobserved reflections were R=0.202 and 0.143, respectively. This showed the high quality of the intensity data obtai ned by the new system presented here.