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The excess resistivity of niobium foil samples due to doped hydrogen increases with concentration up to 8–12 at.% H, which is almost independent of temperature. The Nb-H structure at room temperature or above is quenched to 77 K or 9.5 K by relatively rapid cooling. The abrupt decrease of resistivity is observed, which corresponds to the precipitation of the ordered orthorhombic hydride phase. The superconducting transition temperature Tc is rather insensitive to hydrogen concentration in α solid solution. Hydride phase, however, shows no sign of superconductivity down to 1.3 K. Hydrogen is found to be reabsorbed in niobium after UHV outgassing by storage in air or by immersion in etchants. This is confirmed by weighing the samples and cross-checked by the proton NMR measurements.

The influence of the solute hydrogen on rf properties of superconducting niobium cavities is investigated experimentally. Chemical polishing and too much electropolishing decrease the energy gap and rfbreakdown fields. High-temperature vacuum firing in a UHV furnace decrease the residual loss and recovers the energy gap. Annealed cavities are, however, easily degraded not only by a short period of exposure to hydrogen, but also by a long term storage in air. Chemically polished cavities also show a great enhancement of the penetration depth Ao. These effects can be ascribed to hydrogen which is picked up from etchants or from atmosphere.

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A spin-frozen polarized target of proton and deuteron was constructed for the measurement of spin dependent parameters of hadron-hadron scatterings at the 12 GeV KEK proton synchrotron. The target was also used for experiments at LAMPF-HRS. As the proton and deuteron targets, 1,2-propanediol and fully deuterated propanediol (D-8) with stable Crv complex (EHBA) were used, respectively. The characteristics and performance of the targets are described. Data on the nuclear spin lattice relaxation time (T ln) with proton beam give us information on the Kapitza resistance between the target material and liquid 3He/4He mixture.

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We present the results of an investigation, both theoretical and experimental, of partially occupied and unoccupied electronic distributions in orthorhombic Al 2 Ru. The occupied Al states near E F are p-d hybridized in interaction with Ru 4d states, whereas they are almost purely s-like in character beyond 6 eV from E F . The Ru 4d states are found close to E F ; their interaction with the Al states produces an important depletion of the Al 3s-d and Al 3p distributions. As a result, the Al edges are somewhat pushed back from E F . Thus a wide range of energy with almost no states is present in the occupied band side. E F lies close to the bottom of the unoccupied band where both unoccupied Al states and unoccupied Ru states are present. These results are compared to previous data for icosahedral quasicrystalline Al 70.5 Pd 21 Re 8.5 .