Development of a very cold neutron spin interferometer at the ILL

Abstract We have developed a very cold neutron spin interferometer (VCNSI) for investigations in neutron optics and spectroscopy. As a first step towards such a powerful spin interferometer, a polarized neutron beam line with a mean wavelength of 5.8 nm has been installed at the PF2/VCN beam position at the ILL. We obtained spin interference with high visibility of about 0.79. We made first tests of its feasibility for neutron spin echo spectrometry.