Abstract: We present the results of a Monte Carlo simulation and analytical calculations for a phase space transformer, which accelerates ultra-cold neutrons (UCNs) to cold or thermal neutron energies. We show that due to the sharp energy distribution of UCN’s this kind of neutron device is able to produce monochromatized neutrons with intensities competing today’s most performing time-of-flight instruments, an energy resolution of the order of δE/E ∼ 0.3%, and a horizontal divergency of ∼2° at the planned spallation source for UCN’s (PSI, Switzerland).
Keywords: Neutron scattering, Ultra-cold neutrons, Phase space transformer, Doppler effect, Monte Carlo simulation
Abstract: We performed a feasibility study for a phase space transformer (PST) instrument to be implemented at a cold neutron guide at SINQ (PSI, Switzerland). The study is based on both analytical calculations and Monte-Carlo simulations with particular accent on the energy resolution and intensity. We show that the PST instrument is able to deliver thermal neutrons by up-scattering, with fluxes comparable to the today’s best thermal time-of-flight spectrometers, but with considerably better energy resolution.
Keywords: Monochromator, Phase-space transformer, Doppler effect, Monte Carlo simulation, Bragg’s law