Affiliations: INFM and Dipartimento di Fisica, Università di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy | INFM Operative Group in Grenoble, 6 rue J. Horowitz, F-38042 Grenoble Cedex 9, France | INFM and Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133, Milano, Italy | INFM and Dipartimento di Fisica, Università di Perugia, via A. Pascoli, I-06100 Perugia, Italy
Abstract: Here we report on new results obtained by ad hoc developed McStas simulations of the time-of-flight thermal neutron Brillouin spectrometer BRISP, presently under construction at the ILL. In such a spectrometer a double-curvature focusing monochromator is combined with a multi-beam converging collimator. This configuration, first exploited for BRISP, has been carefully analyzed by developing new specific McStas codes which enable a reliable simulation of the real components, including the detailed features of the monochromator, the background disk-chopper and the honeycomb converging collimator. The present McStas calculations are also used as a guide to refine technical details, such as the optimal arrangement of the crystals on the monochromator surface as a function of the measured mosaic spread. The simulation results are consistent with the expected estimates of both intensity and resolution, and show that BRISP can provide new opportunities for advanced investigations of the low-Q dynamics of disordered and magnetic systems.
Keywords: Neutron scattering, instrumentation, Monte Carlo simulations, time-of-flight, small-angle spectrometer, McStas
