Neutron spin-echo spectrometer at JRR-3M

Abstract

We have designed and have been constructing at the C 2−2 cold neutron guide port of JRR-3M, JAERI, a neutron spin echo spectrometer (NSE). It is equipped with two optimal-field-shape coils for neutron spin precession, a position-sensitive detector, a converging polarizer and a wide-area analyzer. The dynamic range of scattering vector Q covers from 0.005 Å −1 to 0.2 Å −1 and that of energy E from 10 neV to 30 μeV. In a performance test of the precession coils, the NSE signal amplitude P NSE decreased slightly for the neutron beam cross-section of 30 φ mm as the Fourier time t increases up to 25 ns. We have carried out NSE experiments on complex fluid systems and obtained their diffusion coefficient D eff.