SMALL-ANGLE SCATTERING WITH POLARIZED NEUTRONS AT VERY-LOW TEMPERATURES - A NEW SPECTROMETER AT ORPHEE

A spectrometer for small-angle scattering with polarized neutrons has been installed at the ORPHEE reactor. It uses a beam of 8.0 +/- 0.5 An gstrom deflected from the cold neutron guide G5 by Ni-Ti multilayers a nd polarized by a supermirror. A superconducting magnet with a homogen eous horizontal field of 3.5 T and a dilution insert which cools a He- 4-filled sample cavity to 0.2 K makes this spectrometer particularly s uited for studies of spin-contrast variation using dynamic nuclear pol arization. Examples of polarization-dependent scattering from polymers are shown to demonstrate the power of this method. Polarized neutrons are also an advantage in studying magnetic nanosize particles, e.g. t o separate the magnetic and nuclear contributions to small-angle scatt ering.