Monte Carlo Simulation of TOF Single Crystal Spectroscopy

Abstract Results of a first Monte Carlo simulation study of constant-q single crystal spectroscopy using a multiwavelength time-of-flight (TOF) technique are presented. We used the time-of-flight wavelength band monochromatization (TOF-monochromator) set-up with an additional fast double chopper just in front of the sample running quasi-asynchronously with the TOF-monochromator and a repetition rate properly chosen for the TOF energy analysis in the secondary spectrometer and independent of the source pulse frequency (repetition rate multiplication). Instead of a single incoming wavelength, we produce a set of short pulses with an array of wavelengths λ1, λ2,…., λ n , with λ(t) and δ λ/λ(t) periodically changing in time. Choosing the ratio of the TOF monochromator and the sample end fast chopper speed to be an adequate rational number we measure TOF spectra with a quasi continuous set of incoming wavelengths. The data sets so obtained in two TOF dimensions contain constant Q = q + τ energy spectra with q ...