RESOLUTION ENHANCEMENT IN POWDER DIFFRACTION USING STABLE DECONVOLUTION. Derk Reefman Philips Research, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands

A recently developed method will be presented for enhancing the resolution in powder diffraction to approximately 0.025 degrees 2theta, without loss of intensity. Enhancing the resolution in powder diffraction has always been a driving force for the development of sophisicated optics in the beam path of the X-Rays, like monochromators, mirrors, etc. This equipment has contributed significantly to the improvement of the resolution of todays diffractometers. Nevertheless, the ever-increasing demands set by the increasingly complex materials which have to be characterized, ask for even higher resolution. For that reason, synchrotrons are extensively used nowadays.

However, the time allocation for a particular experiment on a synchrotron is limited and one would like to perform experiments with laboratory-equipment without significant loss of resolution. An approach to achieve this is to obtain the instrument function of the equipment of interest, and to correct the measured pattern for the instrumental aberrations. A classical method used to this end is the fourier approach of Stokes. This method has the drawback of becoming unstable for resolution enhancements by more then a factor of 1.5. Recently, it has been shown that application of Maximum Entropy (ME) deconvolution techniques can be used for resolution enhancements up to a factor of 3. A problem however are the computational resources needed. Nevertheless, continuing effort in this direction has now led to a method which, based on ME as well, provides robust access to a way to enhance the resolution of a complete wide range pattern within minutes.