Monte Carlo optimisation of SANS spectrometer at IBR-2 reactor

The operation of the YuMO small-angle neutron scattering time-of-flight spectrometer at the IBR-2 pulsed reactor has proved to be highly efficient for solving different structural problems in chemistry, biology and materials science. At the same time, it has become obvious that further development of the spectrometer may raise its performance to an even higher level. In particular, this concerns the background reduction and obtaining Qmin∼10-3 A-1 (in contrast to presently available 7x10-3 A-1) for a sample of 1 cm in diameter. To design an optimum configuration of the instrument, Monte Carlo simulations were performed. Several options of a virtual instrument consisting of a bender and/or neutron guide (curved, straight, focussing), collimation system, sample and detector were investigated. An optimum configuration of the small-angle scattering spectrometer at IBR-2 is proposed. (author)