Design of Bandwidth Choppers for the High-Pressure Neutron Diffractometer at the CSNS

A bandwidth chopper system was analytically designed in detail for a high-pressure neutron diffractometer at China spallation neutron source. A chopper system with two single-disk choppers and one double-disk chopper was proposed for this diffractometer based on the analysis of neutron time-of-flight method. Two modes, serving two scattering rooms, can be obtained by adjusting the rotational frequencies and the phase angles of the double-disk chopper. These analytically obtained parameters were further assessed by Monte-Carlo simulations via a package of Vitess, and the simulated results were in good agreement with theoretical expectations.