A statistical approach to correct X-ray response non-uniformity in microstrip detectors for high-accuracy and high-resolution total-scattering measurements

An unbiased approach to correct X-ray response non-uniformity in microstrip detectors has been developed based on the statistical estimation that the scattering intensity at a fixed angle from an object is expected to be constant within the Poisson noise. Raw scattering data of SiO2 glass measured by a microstrip detector module was found to show an accuracy of 12 σ PN at an intensity of 106 photons, where σ PN is the standard deviation according to the Poisson noise. The conventional flat-field calibration has failed in correcting the data, whereas the alternative approach used in this article successfully improved the accuracy from 12 σ PN to 2 σ PN. This approach was applied to total-scattering data measured by a gapless 15-modular detector system. The quality of the data is evaluated in terms of the Bragg reflections of Si powder, the diffuse scattering of SiO2 glass, and the atomic pair distribution function of TiO2 nanoparticles and Ni powder.
Source: Journal of Synchrotron Radiation - Category: Physics Authors: Tags: total scattering pair distribution functions microstrip detectors flat-field calibration Poisson noise research papers Source Type: research