Numerical simulation study of the performance of a small neutron three axis spectrometer

This article describes Monte Carlo computer simulations comparing the performances of a conventional neutron three axis spectrometer (TAS) and a micro-TAS, a μTAS, designed to be as compact as seems practical. The simulations show that the μTAS delivers performance (intensity at equal resolution) equivalent to that of a normal TAS. The μTAS should be very cheap to build and a “farm” of several such small machines at a single conventional instrument position should greatly increase the TAS beam time available from a given source. A μTAS can deliver significantly larger beam angular divergence at the sample and detector, thus extending the accessible resolution-intensity range, whether using flat or curved monochromating crystals.