Quasielastic high-resolution direct geometry TOF spectrometers. at steady-state reactors and at spallation sources

Intensity optimization at a given resolution of direct-geometry multi-chopper time-of-flight (MTOF) spectrometers for high-resolution QENS experiments is discussed in view of further developing this technique to allow more-efficient measurements and more-extensive variation of the time scales, on one and the same instrument. We show that the total intensity of a modern MTOF spectrometer as compared to the best existing can be increased by two orders of magnitude at continuous neutron sources and by at least three orders of magnitude at future pulsed neutron sources.