A description is given of the prototype polarized neutron reflectometer installed at the intense pulsed neutron source. This instrument is designed for determining the magnetic depth profiles near the surfaces of ferromagnets and superconductors, by measuring the spin-dependent reflectivities of a well-collimated (0.01°) beam of cold neutrons from surfaces of a few cm2. Magnetic profiles can be determined with the spatial resolution of 40 Å, over thicknesses up to 5000 Å. Variations of the magnetic flux of the order of 10−5 G cm2 can be detected.

The momentum density of the quantum solid hep 4 He has been measured at 1.70 K at the molar volumes 18.20 and 19.45 cm 3 . The measurements were made with pulsed incident neutrons of energy 505 meV, and with momentum transfers in the range of 12 to 22.5 A -1 . The momentum density is obtained from the inelastic-scattering spectrum at each of eight scattering angles. The measured distribution is Gaussian and the derived kinetic energies are larger than proposed by existing theories.

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The interdiffusion of Cadmium Arachidate (CdA) in Langmuir-Blodgett films has been studied by neutron reflection at the Intense Pulsed Neutron Source of Argonne National Laboratory. One of the samples consisted of a few layers of perhydro H-CdA deposited on a silicon support, overlayered with a few layers of deuterated D-CdA, for a total thickness of ∼300 Angstroms. In a second sample the layers of perhydro-and deuterated- CdA were separated by two monolayers of Hn-octadecene/co-maleic acid copolymer. When heated for 15 minutes at 70°C, well below the disorder temperature [1], approximately 25% of the D-CdA molecules were replaced by H-CdA molecules, although the overall Langmuir-Blodgett film structure is known to remain unchanged [1]. The presence of copolymer layers limited the interdiffusion process to about 5%.