No abstract available

[en] In order to study the irradiation effect on alumina ceramic, electron beam irradiation experiment has been performed in electron beam irradiation facility at JAERI. It is possible to irradiate the electron beam at the maximum peak beam current of 30 mA and the maximum beam energy of 3 MeV in this facility. In the experiment the electron beam at the energy of 2.5 MeV was irradiation on the sample of alumina ceramic. The flexural strength of these samples was measured in accordance with the regulation of the JIS. The dose of the electron beam which corresponds to 300 MGy at the beam energy of 2.5 MeV has been irradiated to the 14 kinds of alumina ceramic. The result showed three patterns of the flexural strength for the absorption dose. (author)

[en] Deuterium retention and desorption properties of SiC/SiC composite after deuterium ion irradiation were investigated by means of thermal desorption spectroscopy. Carbon composition measured by Auger electron spectroscopy was considerably large, 90 at.%, which was due to the special heat treatment to the SiC fiber. X-ray diffraction analysis suggested that the material investigated was amorphous silicon carbide with fine crystalline phases. After deuterium ion irradiation, retained deuterium desorbed in forms of HD, D₂, and CD₄. Thermal desorption spectrum of D₂ had a single peak at 1050 K. The D₂ spectrum was similar to that of CFC rather than that of SiC. Amount of retained deuterium was approximately 5x10²¹ D/m², which was comparable to that of CFC or SiC. Amount of desorbed CD₄ was 5x10¹⁹ CD₄/m², which was approximately 1/4 of the CFC. (author)

[en] Deuterium retention of carbon dust was investigated by two methods, i.e. one is deuterium gas absorption and the other is deuterium ion irradiation. After the gas absorption, retained deuterium desorbed in forms of D₂ and HD. Saturated amount of retained deuterium due to the gas absorption at 100 Pa was approximately 10^-3 in the atomic ratio D/C, when the temperature range was from 973 K to 1173 K. This amount was 10 or 100 larger than that of powdered graphite or bulk graphite, respectively. However, trapping energy of deuterium in the carbon dust was 0.22 eV, almost the same as that of the graphite. After the deuterium ion irradiation to the carbon dust, the retained deuterium desorbed in forms of D₂, HD, CD₄ and C₂D₄. The amount of retained deuterium due to the deuterium ion irradiation was 0.55 in the atomic ratio D/C, almost same as the graphite. (author)

[en] In a nuclear fusion device, plasma facing materials (PFMs) such as graphite are bombarded by extremely high heat and particle fluxes during an abnormal discharge called as disruption. As a result of the disruption, the PFMs are eroded and deposited on the wall. In the case of graphite plasma facing material, carbon dusts are produced. Flaky carbon dust was produced from isotropic graphite by electron beam evaporation. The absorption properties of deuterium in carbon dust were investigated by changing an absorption temperature (773-1173 K), time (10 min-24 hr) and deuterium gas pressure (1-100 Pa). The amount of adsorbed deuterium was evaluated by using thermal desorption spectroscopy. Deuterium was desorbed from the carbon dust at the temperature higher than 873 K in form of HD and D₂. At the absorption temperature of 973 K and the pressure of 100 Pa, the amount of deuterium absorbed in the dust saturated within 5 hr. This saturation level was one or two orders of magnitude larger than that of isotropic graphite. The heat of solution for deuterium was 0.27 eV which was almost the same as that of isotropic graphite. (author)

[en] Steric control of chemical reactions on surface is one of the goals for surface scientists. An oriented-molecular beam which we produce utilizing the Stark effect of molecules is a technique to complete such as mission. This technique allows us to select specific rotational quantum states and orientations of the reagent molecules. Thus, we have designed, built and tuned up the UHV-compatible oriented-molecular-beam machine for the elucidation of the reaction dynamics on well defined surfaces. The newly developed machine consists of four differentially pumped chambers. The base pressure was 5 x 10^-8 and 1 x 10^-8 Pa for the hexapole chamber selecting the quantum state of molecules and the collision chamber for the surface-reaction analysis, respectively. We measured the focusing curve of CH₃Cl beam to check the performance of the machine. We could clearly resolve the peaks corresponding to each rotational quantum state. According to the trajectory simulation including the second-order Stark effect, we assign each peak in the focusing curve to the specific rotational state and also estimate the orientational distribution. We achieved a good resolution for the selection of the states with |JKM> = |111> and |212> state. (author)

No abstract available

[en] By the use of the JIPP T-II torus device (IPP Nagoya), an experiment on ECR discharge cleaning was carried out. The aim was focused to finding the effect of the cleaning on tokamak discherges. To characterize the tokamak discharge property, mean plasma resistivity, intensity of an oxygen ion spectral line and mean electron density without gas puffing were measured. The first cleaning operation for 5 hours drastically i improved the purity of the tokamak discharge plasma. The succeeding 75 hours' cleaning gave the wall surface condition corresponding to Zsub(eff) = 1.0. The cleaning plasma had the electron temperature of 5 eV and the density of about 1 x 10¹⁰ cm^-3 with a hydrogen pressure of 2.9 x 10^-2 pa and a microwave power of 800 W. (author)

[en] The research on ion-induced sputtering has been continued for a long time, since a hundred or more years ago. However, it was only in 1969 by Sigmund that the sputtering phenomena were theoretically arranged into the present form. The reason why the importance of sputtering phenomena have been given a new look recently is the application over wide range. This paper is a review centering around the mechanism of causing sputtering and its characteristics. Sputtering is such a phenomenon that the atoms in the vicinity of a solid surface are emitted into vacuum by receiving a part of ion energy, or in other words, it is a kind of irradiation damage in the vicinity of a solid surface. In this meaning, it can be considered that the sputtering based on the ions located on the clean surface of a single element metal is simple, and has already been basically understood. On the contrary, the phenomena can not be considered to be fully understood in the case of alloys and compounds, because these surface conditions under irradiation are not always clear due to segregation and others. In the paper, the physical of sputtering, single element sputtering, the sputtering in alloys and compounds, and the behaviour of emitted particles are explained. Finally, some recent topics of the sputtering measurement by laser resonant excitation, the sputtering by electron excitation, chemical sputtering, and the sputtering in nuclear fusion reactors are described. (Wakatsuki, Y.)

[en] Various applications of ion beam sputtering to the high resolution electron microscopy have been studied. Ion beam sputter-etching has been used to reduce granularity of carbon film prepared by routine vacuum evaporation. Also, it can be used to remove contamination layer of the organic molecules arising from the dispersion liquid (distilled water) of the imogolite crystals. The resolving power (3.3 nm) of the atomic shadowing which is obtained by the sputter deposition in similar to the routine vacuum shadowing method is obtained by the measurement of width of tungsten shadow-casting appearing at the imogolite crystals with 2 nm diameter of the lod, where shadowing angle phi is 30⁰. Furthermore, the fundamental characteristics of sputter-etching for the casein and ferritin particles are examined with respect to the varying sizes and distributions, which are dependent on both accelerating potential of argon ion beam and bombardment time. It is found that the ion beam sputter-etching is very useful to remove the surface layers contaminated over the rigid sphere protein molecules under the non-thermal working state which is experimentally confirmed from the unaltered latex inserted into the specimen and more clearly reveals intracellular structure of casein and ferritin particles. (author)