Optimization of a focusing monochromator for neutron strain-scanning diffractometer

Comparison of mosaic and elastically deformed crystals as possible candidates for horizontally focusing monochromators at a high-resolution powder diffractometer is presented. The comparison is based on Monte Carlo simulations used to optimize instrument performance for several variants of configuration. The results show that elastically deformed crystals can be optimized better than the mosaic ones in a wide range of wavelengths, except for the case when focusing in momentum space requires a nearly flat monochromator. A set of diffraction profiles measured at a strain-scanning diffractometer configured with an elastically bent Si monochromator is compared with simulations in order to validate the simulations.NRC publication: Ye