The SuperKEKB, the upgrade of the KEKB, is an electron-positron collider with asymmetric energies, that is, 7.0 GeV electrons and 4.0 GeV positrons, aiming at a luminosity of 8×10³⁵ cm⁻² s⁻¹. The construction of the new vacuum system for the SuperKEKB has been ongoing since 2010, as a key item of the upgrade project. The fabrication of more than 1000 beam pipes, vacuum pumps and bellows chambers in each, and other various vacuum components had almost completed in 2014. Before the installation into the KEKB tunnel, all of the new beam pipes were basically baked. A thin TiN film was coated on the inner surface of the beam pipes for the positron ring as a countermeasure against the electron cloud effect (ECE). Although several problems, such as cracking of the welding lines of the aluminum beam pipes, the relatively high air-leak rate at the connection flanges, occurred during the construction work, approximately 99% of the beam pipes were successfully installed by the end of November 2015. The activation of the NEG pumps in the tunnel fully started at the beginning of 2015, and has also been completed in approximately 97% of the ring. The vacuum system will be ready in this year with the aim of starting the first commissioning in the beginning of 2016.

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 To demonstrate the function of a gas sheet for measuring the 2D profiles of accelerated beams, the following experiments were performed: 1) A gas sheet with a thickness of 1.5 mm and a density of 2×10⁻⁴ Pa was produced by the deep slit, and the shape of the sheet was improved by the thin slit. 2) For an electron beam of 30 keV and a diameter greater than 0.35 mm, the position and the 2D profiles were appropriately measured using the gas sheet.

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 The production of negative ions is one of the key issues in material processing and the neutral beam generation in nuclear fusion devices. Negative ions are known to be produced by the electric charge exchange during the ion scattering on material surfaces. We measured the production of negative ions using stable oxide materials with low work functions, instead of commonly used alkali metals. Negative ions, generated from barium oxide and calcium oxide surface during He⁺ scattering, are successfully detected by newly established detection system by means of pulse counting with wide dynamic range.

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 The surface morphology of KBr (001) irradiated by electrons is observed by first decorating the surface with Au particles and then replicating it with C foils. For the electron irradiation and the subsequent decoration, we integrated an electron-beam gun and a vacuum evaporator. The sample surface was irradiated by a 1.5 keV electron beam; small Au particles were then evaporated onto the surface. Although the decorated sample was prepared in an ultra-high vacuum condition, the C foil was evaporated in a separate high-vacuum evaporator. To avoid deliquescence of the sample surface, contact between the sample and the ambient air was minimized by transporting the sample between the two vacuum chambers in a N₂-gas-filled enclosure. Imaging the surface with a transmission electron microscope revealed many rectangular monolayer pits. The mean area of the pits and the associated standard deviation are presented versus temperature; the mean pit area increases with temperature.

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 We have investigated nano-scale luminescence from multiwalled carbon nanotube (CNT) adsorbed on Au(111) using scanning tunnleing microscopy (STM) light emission spectroscopy. Dry contact transfer (DCT) method was used to deposite an isolated single CNT onto the clean substrate in the ultrahigh vacuum (UHV). We found that the surface density of CNT on Au(111) is increased by presonicating the CNT powder in 1,2-dichloroethane. STM imagings revealed that the cleaness of the surface is maitained at the area where isolated CNTs exist while the surface is likely to be contaminated at the area where the bundled CNTs exist. The STM light emission spectrum obtained from the isolated single CNT on Au(111) exhibits the spike-like peaks observed in the visible light range, which is caused by the electronic transitions between the electronic bands of semiconductive CNT.

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 The influence of relative humidity on the preamp of a quartz-oscillator pressure sensor was investigated because temperature affects the output from the pressure sensor not only through the quartz oscillator but also through the preamp. The pressure sensor used in this study consists of a quartz oscillator, the output of which is less affected by temperature, and a preamp. The relative humidity dependence of the preamp was obtained by varying humidity at the preamp, while keeping humidity at the quartz oscillator constant. It was found that the fluctuation of the output from the pressure sensor at 10, 20, 30, 40, and 50℃ was below 0.16% of the average output at maximum, which is smaller than the minimum detection level when used for hydrogen sensing. These results confirm that the relative humidity does not significantly affect the output through the preamp of the quartz-oscillator pressure sensor.

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 The SuperKEKB, the upgrade of the KEKB, is an electron-positron collider with asymmetric energies, that is, 7.0 GeV electrons and 4.0 GeV positrons, aiming at a luminosity of 8×10³⁵ cm⁻² s⁻¹. The construction of the new vacuum system for the SuperKEKB has been ongoing since 2010. The target vacuum pressure in the main ring is on the order of 10⁻⁷ Pa on average at the designed beam currents. The synchrotron radiation (SR) is received by the beam pipes along the ring. Therefore, the distributed pumping scheme is adopted to effectively evacuate the beam pipes. A linear pumping speed of approximately 0.1 m³ s⁻¹ m⁻¹ is required if we assume a photo-desorption coefficient (η) of 1×10⁻⁶ molecules photon⁻¹. A new built-in pump assembly using the multi-layered non-evaporable getter (NEG) was designed for an antechamber space of the new beam pipes as a main pump at the arc sections. The linear pumping speed combined with an RF-screen is expected as approximately 0.1 and 0.18 m³ s⁻¹ m⁻¹ for N₂ and CO, respectively. The measured effective pumping speed using a real beam pipe was reasonable one for N₂. The NEG activation in the tunnel after installing the beam pipes are ongoing. The vacuum pressures on the order of 10⁻⁸ Pa on average are mostly achieved after the NEG activation.

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 Hydrogen fuel production from methane gas is studied by using the plasma reforming technology using dielectric barrier discharge (DBD) which is eco-friendly method without generating harmful gas of carbon monoxide or carbon dioxide. Hydrogen production properties were evaluated in velocity control of gas flow due to the reactor gaps and gas convection time during DBD plasma reforming. High hydrogen production was attainable by using the plasma reactor having wide gap at higher input power region. Moreover, it was found that hydrogen production was highly reformed at lower input power by making use of the convection effect of induced gas flow by the DBD plasma generated in airtight reactor filled up with the gas.

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 Fabrication process for Spindt-type field emitter arrays with volcano-structured focus electrode was proposed. The material for the emitter, gate, and focus electrode were optimized from the viewpoint of fabrication process. The emitter material is limited to a few kinds of metal by the process using photoresist. However, using a buffer layer or surface coating method expands the species of emitter material. Our process can control the height of gate and focus aperture; therefore, the optimized structure for specific application will be available.

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