Improved energy-dispersive X-ray scattering system based on polycapillary collimation and a Silicon Drift Detector

We have developed a setup for low angle energy dispersive X-ray scattering measurement employing two key components: i) a Silicon Drift Detector (SDD) which can provide energy resolution close to Fano limit at fast processing times and ii) an X-ray collimator based on parallel polycapillary technology that allows angular resolution in the milli-radiant range. Combining these features an instrument has been developed for fast acquisition of X-ray scattering intensity profiles with resolution in momentum space of few percent. In order to fully assess the achievable performance of the setup with its novel features, a reference sample with known momentum transfer distribution was measured. One key issue studied in detail is the impact of the well-known energy dependence of the acceptance angle of the parallel polycapillary collimator. To this purpose the measured linear scatter coefficient with the polycapillary collimator has been compared with the one obtained (in the same experimental conditions) with a multi-hole brass collimator.