Polarimetric neutron spin echo

Neutron spin echo INSE) spectroscopy inherently involves polarization analy sis features. Thus, the very principle of paramagnetic NSE used for the stu dy of magnetically isotropic systems is based on the vector properties of t he neutron polarization change in the scattering, which implies that the in coming and outgoing neutron spin directions are not parallel. Another, conv entional polarization analysis feature is the opposite sign of the NSE sign al for nuclear and nuclear-spin incoherent scattering, or the signal parall el and perpendicular magnetic fluctuations in the presence of a strong magn etizing field. In these cases the measured NSE spectra are the algebraic su ms of two components. In its actual form, however, NSE does not allow one t o investigate spin-flip and non-spin-Rip scattering channels independently from each other. At the expense of rather moderate loss of signal it is, ho wever, possible to generalize the NSE technique for the study of a given ch annel of spin-dependent scattering processes in the most general sense of n eutron polarimetry. This means to perform inelastic NSE analysis on the par tial scattering cross-section corresponding to the transition from any inco ming spin direction P to any outgoing spin direction P'. A method of combin ing NSE with neutron polarimetry will be described together with a simple e xample of experimental realization. (C) 2001 Elsevier Science B.V. All righ ts reserved.