THE NEUTRON REFLECTOMETER (C3-1-2) AT THE JRR-3M REACTOR AT JAERI

A neutron reflectometer has been installed at the cold neutron guide t ube (C3-1-2) of the JRR-3M reactor at JAERI. Incident neutrons for the reflectometer have a long wavelength of 12.6 Angstrom, with a wavelen gth resolution of 3.2%. The reflectometer has the advantage of a large reflection angle which is appropriate for studies of low-q and off-sp ecular phenomena. The neutron intensity reduction due to the long wave length is substantially compensated by the relatively coarse beam dive rgence and wavelength resolution. The reflectometer is mounted in vert ical geometry to yield a beam of 3x40mm(2) and is applicable to measur ements of mirror systems formed on flat substrates. Applications of th e reflectometer to neutron optics and polymer studies are demonstrated and discussed.