Performance Test of CW 300?GHz Gyrotron FU CW I

A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kV and the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE_22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B _c at the cavity is adjusted at a proper value. However, within a range of B _c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes.     

Polarized proton target for RI Beam experiments

We have constructed a polarized proton solid target system for radioactive nuclear beam experiments at the Center for Nuclear Study, the University of Tokyo. The proton polarization is based on an electron population difference in a photo-excited triplet state of pentacene molecule. The target system was completed in 2003 and applied to a RI beam experiment in 2003 and 2005 by using the projectile fragment separator, RIPS at RIKEN. The maximum polarization reached 20% under the condition of T=100 K and B=0.09 T. Overview of the polarized target and its application in physics experiments at RIPS and RIBF of RIKEN are presented.     

Behaviour in solution of piezoelectric quartz crystals coated with poly(vinylpyridines). Application to the determination of copper(II)

Poly(2-vinylpyridine) or poly(4-vinylpyridine) coated on a piezoelectric quartz crystal adsorbed copper, thus decreasing the oscillation frequency. The bound copper could be removed by EDTA solution. Poly(4-vinylpyridine) is recommended to determine copper (5–35 μM) in a maleate buffer at pH 6.6 flowing over the coated crystal for 5 min. Iron(III) and cadmium interfered.     

Orientational relationship among main and side chains of a polyimide alignment layer, liquid crystals monolayer and bulk pretilt angle

We have determined the orientational distribution of cyano-substituted side chains of a rubbed polyimide film, and a liquid crystal monolayer adsorbed on the film, by means of optical second harmonic generation. With the orientational distribution of a main chain that was measured in a previous study by means of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, we have obtained the correlation of all the orientational distributions contributing to the alignment of LC molecules, i.e. pretilt angle. We find that the side chain plays a role in increasing the pretilt angle, but in the case of rubbing strength dependence, the main chain has stronger correlation with the pretilt angle than has the side chain.     

Modeling of filament discharge development in a XeCl excimer laser

Dynamics of a filament discharge in a discharge-excited XeCl excimer laser medium has been simulated for a sequence of discharge pulses (shots). In the present model a filament discharge is triggered at a microprotrusion on a cathode surface. After the first discharge initiation, a hot spot is created near the cathode, then filament develops toward the anode in the second shot. Images of the filament discharge development and its properties in a XeCl excimer laser are presented