Numerical Simulation of a Beam Divergence Correction for NRSE Spectrometer using Polygonal 2D-focusing Supermirrors

By inserting two-dimensional (2D) elliptical focusing mirrors between each pair of RSFs in neutron resonance spin echo spectrometer, the flight path lengths between the pair of RSFs can be made equal even for any divergent beam. We investigate numerically the feasibility of using polygonal 2D elliptical focusing mirrors as beam correction devices, and we show the relation of the energy resolution and the neutron intensity including effect of gravity.