M. Matsuyama
Hydrogen Isotope Research Center, Organization for Promotion of Research, University of Toyama

Abstract
Research and development of technologies for the safe handling of high-level tritium are indispensable for realization of a thermonuclear fusion reactor, and tritium measurement techniques play an important role in this subject. More than 35 years have been spent for the studies in this field at the Hydrogen Isotope Research Center (HRC), University of Toyama. Nuclear fusion systems need new measurement techniques that work in the limited range of conditions with high tritium level, as well as at the environmental level, because nearly pure tritium is used as fuel particles in the fusion system. Therefore, new measurement techniques have been investigated so far at HRC, and some of them have already played a certain role in the research on tritium-material interactions, but they are not enough yet. Further studies on measurement techniques will be required to establish the ability for precise control of concentration, amount, and/or distribution of tritium under various conditions.

Y. Hatano¹, Y. Nobuta^2
1Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan
²Division of Quantum Science and Engineering, Graduate School of Engineering, Hokkaido University Sapporo 060-8628, Japan

Abstract
In fusion devices with plasma-facing components manufactured from carbon-based materials, co-deposition of hydrogen isotopes and carbon takes place in regions where sputtering rate is relatively small. Fuel retention and recycling depend on properties of those deposits. Glow-discharge optical emission spectroscopy (GDOES) is one of attractive techniques to analyze chemical composition and thickness of these deposition layers. However, influence of hydrogen content on sputtering of these layers by glow-discharge plasma is not fully understood. In this study, two different types of carbon layer with quite different hydrogen content were deposited on stainless steel substrate, and sputtering rate during the GDOES measurement was examined for better interpretation of results obtained.

M. Inoue^a,T. Kiriki^a,Y. Honda, K. Shinagawa^b,T. Abe^a
aHydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan
^bYoutech Co., Ltd. Nishihirai 956-1, Nagareyama-shi, Chiba 270-0156, Japan

Abstract
Effects of the angle of the target plate on particle surface modification by the polygonal barrel-sputtering method were investigated by preparing TiO₂-supported Ru (Ru/TiO₂ ) samples. The sputtering with Ru was conducted at the target angles of 0, 20, and 45°. The results showed that the Ru nanoparticles deposited on the TiO₂ particles had small and uniform sizes of ca. 2–4 nm, regardless of the target angle. However, the amount of Ru deposited gradually decreased with the change in the target angle from 0° to 20 and 45°. On the other hand, our sputtering system was redesigned by closing one side of the polygonal barrel and attaching a stainless-steel spring cap to the target holder located on the opposite side of the barrel, in order to avoid the spillage of particles. As a result, we succeeded in an increase in the sample yield (over 90 %), which will be useful for the practical application of the polygonal barrel-sputtering method.

S. Akamaru¹, H. Taka², M. Hara¹, K. Nishimura², M. Matsuyama^1
1Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan
²Faculty of Engineering, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan

Abstract
The thermodynamic properties of the TiFe_0.9Co_0.1–H system and its magnetic properties with various hydrogen contents were examined. The pressure-composition isotherm curves showed a plateau region, and the change in the enthalpy with monohydride formation was similar to that of TiFe. From the conventional magnetic properties examinations, TiFe0.9Co0.1 was found to show no magnetic transition down to 10 K. The magnetic susceptibility of TiFe_0.9Co_0.1 increased with hydrogen uptake, but no ferromagnetic behavior was observed up to the hydrogen content of TiFe_0.9Co_0.1H_0.6 at room temperature. The change in magnetic susceptibility with hydrogen uptake could be explained qualitatively by the band structure calculation.

A. Taguchi, Y. Nagaki, Y. Yoneyama
Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract
Repeated washing with ethanol and hexane of polyvinylpyrrolidone (PVP)-capped Pt nanocolloid could generate an uncovered Pt surface. Pt dispersion was significantly improved by this washing as compared to unwashed Pt. IR spectrometry revealed that PVP-free Pt supported on SiO₂ could be obtained by calcination at 200 ℃, while unwashed Pt required more than 250 ℃.

M. Hara, H. Futagami, S. Abe
Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555, Japan

Abstract

A conventional liquid scintillation analyzer is typically equipped with two photomultiplier tubes to distinguish the signals of disintegration events from the noise of photomultipliers. However, commercially available liquid scintillation analyzers are not designed to provide signal output from each individual photomultiplier. Considering this limitation, the liquid scintillation analyzer was assembled with NIM modules so that it could generate a bifunctional scintillation spectrum from the two photomultipliers. The pulse height of the bifunctional spectrum obtained increased with decreasing the quenching. This change was consistent with the principles of the liquid scintillation counting.