The Backscattering Instrument MUSICAL and Test Experiments

Abstract MUSICAL represxsents a concept for a neutron backscattering instrument designed to be used on a pulsed neutron source. By using many crystals as monochromators, the multiplexing effect should give an intensity gain compared to a conventional single monochromator spectrometer, which is proportional to the number of crystals. A novel multiple silicon crystal is used as the monochromator. Test experiments were performed using 21 unpolished silicon crystals each separated by 4.7 cm and temperature differences δT of 10°C or 20°C between neighbouring crystals. As expected the resolution function has a complicated structure. The energy width is estimated to be 400 neV which is close to the best energy resolution available on current backscattering spectrometers.