Effective field integral subtraction by the combination of spin echo and resonance spin echo

Abstract

In contrast to other inelastic neutron scattering methods, neutron spin echo (NSE, F. Mezei, Z. Phys., 1972, 255, 146) tests sample dynamics directly in the time domain. The corresponding energy resolution is the highest one of all neutron scattering methods. In NSE, the spin phase accumulated in magnetic fields before and after the sample is compared. The Neutron Resonance Spin Echo (NRSE) technique (R. Gähler and R. Golub, Z. Phys. B, 1987, 65, 269) relies on a similar principle as NSE. Using additional RF frequency coils allows a significant reduction of the dimensions of the static magnetic field coils. The dynamic range both in NSE and NRSE is restricted to three orders of magnitude, at most. The tuning of an NRSE instrument is, moreover, restricted to few resonance frequencies, predetermined by electrical conditions. In order to increase the flexibility of NSE instruments, and to enable studies of dynamics spread over a wider range of the spin echo time, we combined both methods, NSE and NRSE, in a single setup. A test experiment with the new NSE-NRSE setup at IN11 (Institut Laue Langevin, Grenoble), has demonstrated its high flexibility, and that there are no electrical limitations with respect to energy resolution tuning. Our NSE-NRSE setup overcomes restrictions of the dynamic range of both the NSE and the NRSE method.