[en] In the practical use of superconducting magnet, regardless of low or high temperature' superconductor, combination of the superconductor and high conductive matrix of normal metal is now indispensable. This binding property is one of the key points whether superconducting characteristics are fully attained or failed prematurely in the practical magnet. But this binding evaluations is not so easy, because even in the mechanical well-jointed conductor in the room temperature, it often appears poor in electric and magnetic property in cryogenic temperature by the contraction of the conductor. And sometimes, these often happen that critical current change time to time of an every trial of current loading. This must be understood that the binding condition between the metals changes by time to time of heating and re-cooling at/after every quench. So it must become very important to evaluate these bindings' properties at cryogenic temperature and with real current charging. Here we report new technique for evaluating these bindings by observing ultrasonic spectra of acoustic emissions when a normal transition is propagated along the superconductor. We have discovered a simple but important fact that good contacting conductor has an emission of this ultra-sound with sharp resonating frequency peak or peaks at around highest spectrum in near 1.0 MHz area

[en] An advanced slot antenna was developed and the enlargement of surface wave plasma was experimentally investigated using the array configuration of slot antennas for large-area nanocrystalline diamond (NCD) film depositions. An original-geometry slot antenna with an annular shape, designed in this work, permitted broad microwave radiations and vast extent of plasma propagations. Uniform plasmas were produced over a deposition area of 600 x 360 mm² with densities of ∼10¹⁷ m^-3 using hydrogen gas by an array configuration of five slot antennas and four rows of the array. A uniform (thickness variation: 10%) and smooth (Ra: 11 nm) NCD film deposition on a 300 x 300 mm² borosilicate glass plate was achieved using the plasma and a mixed gas of H₂/CH₄/CO₂.

[en] The next generation of compact tandem-type DD or DT neutron generators requires a robust electron stripper with high charge exchange efficiency. In this study, stripping foils of various types were tested, and the H^- to H⁺ conversion efficiency, endurance to the heat load, and durability were investigated in terms of suitability in the tandem-type neutron generator. In the experiments, a H^- beam was accelerated to about 180 keV, passes through a stripping foil, and produces a mixed beam of H^-, H⁰, and H⁺. These ions were separated by an electric field, and detected by a movable Faraday cup to determine the conversion efficiency. The experimental results using thin foils of diamond-like carbon, gold, and carbon nano-tubes revealed issues on the robustness. As a new concept, a H^- beam was injected onto a metal surface with an oblique angle, and reflected H⁺ ions are detected. It was found that the conversion efficiency, H⁺ fraction in the reflected particles, depends on the surface condition, with the maximum value of about 90%.