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At the Wakasa Wan Energy Research Center (WERC), an accelerator system with a 5 MV tandem accelerator and a 200 MeV proton synchrotron is used for ion beam analyses and irradiation experiments. The study of cancer therapy with a proton beam is also performed. Therefore, the stable operation and efficient sharing of beam time of the system are required, based on the treatment standard. Recent developments and the operation status of the system put stress on the tandem accelerator operation, magnifying the problems.

Hydrogen isotope separation effect by electrolysis of water was theoretically investigated and was compared with experimental results. The separation mechanism was analyzed as the hydrogen isotope exchange reaction between water and diatomic hydride that consists of hydrogen and cathode material. The equilibrium constants of the isotope exchange reaction were calculated from reduced partition function ratio. Using the constants, the separation factor (SF) of the isotopes was calculated according to the two-phase distribution theory for isotopes. Experimentally, light or heavy water spiked with tritiated water was electrolyzed by a device with a solid polymer electrolyte, which equipped with SUS, Ni, or carbon cathode. Thus, the SFs were experimentally obtained. Calculated SFs were well agreed with the experimentally values for SUS and Ni cathodes, and that for carbon cathode was somewhat small then the experimental value.

One of the advantages of Bi-2212 is that a high J/sub c/ value can be obtained in wires with various shapes and filament configurations. Realization of a high J/sub c/ round wire made it possible to fabricate many kinds of cable developed for applications of low temperature superconductors (LTC). We successfully fabricated a 30-strand Rutherford cable using 0.8 mm/sup d/ round wire. Optimization of cabling factor enables to reduce the I/sub c/ degradation at the cable edge. I/sub c/ values were about 650-750 A at 65 K in a noninductive winding condition, which corresponds to 11-13 kA at 4.2 K in self-field.

Recently, superconducting properties of high Tc superconductors (HTS) have been highly improved and using performance of HTS a conceptual design of a fusion device was performed by Japan Atomic Energy Research Institute (JAERI). HTS has a capability to produce a magnetic field of higher than 16 T, which is required in such a fusion power reactor. Aiming at development of the conductor, a trial fabrication of a 10-kA 12-T conductor was started using round Ag-alloy sheathed Bi-2212 strands, which has best performance at 4.2 K, 16 T at present. The conductor has about 34-mm diameter, and is composed of 729 HTS strands. Operating temperature is designed at not only 4 K but also 20 K. The cable of the conductor is solder-coated on the surface to use specific heat of the lead as much as possible, which at 20 K is almost comparable with specific heat of SHe at 4.5 K, 0.6 MPa. From the tests of the conductor, the fabrication of large HTS conductor and 10 kA operation at 12 T, 18 K /spl sim/ 20 K were successfully performed and the first step of developing work of HTS conductor for fusion application was achieved.

To survey the applicability of existing HTS wires for SMES, five kinds of cryocooler-cooled HTS coils were fabricated and tested to estimate fundamental characteristics of HTS wires. Critical current, run-away current, and ac losses were measured. To confirm the effect of electromagnetic force to the coil performances, critical currents were measured under high magnetic fleld of 14 T with liquid helium cooling. The HTS wires used for the coils are three types of Bi2212 wire and two types of Bi2223 wires. We have wound these wires to little coils of 14 cm outside diameter, 10 cm height with cryocooling. As a result, a difference of critical current characteristic of a Bi2212 wire and a Bi2223 wire was not big at the temperature of 20 K, but a critical current of a Bi2212 wire fell at 50 K greatly, and the HTS-SMES design that utilized a temperature margin by cryocooler-cooled system understood what a Bi2223 wire was suited for.

We have developed HTS cables using Bi-2212 round wires, which have high mechanical strength and an average J/sub c/ of 200 kA/cm/sup 2/ at 4.2 K in self-field. Four designs of cables were fabricated in this work and those tables could carry I/sub c/ values from 1 kA to 10 kA at 4.2 K and self-field depending on the number of strands. A 70m-long 20-strand Rutherford cable was successfully manufactured. Optimization of heat treatment conditions was effective to reduce I/sub c/ degradation observed in the case of heat treatment with a long length. I/sub c/ values of a Rutherford cable were measured under loading at 4.2 K in 4 T. The critical values of the stress on face loading and edge loading were 60 MPa and 100 MPa, respectively. We successfully obtained high J/sub c/ value of 500 kA/cm/sup 2/, which was almost double that of the conventional wires capitalize "Rutherford".

An 80 meter long Rutherford cable was fabricated with 20 strands of 0.8 mm diameter Bi-2212 wire. The conductor utilized in this cable was a double stack design (7 × 61) comprising 427 filaments. The critical current (Ic) of the cable was measured at liquid helium in applied magnetic field up to 4T. The Ic results of the cable show no degradation when normalized to the strand. The cable was sectioned into four 17-meter lengths and one 10-meter piece. These sections were heat treated and the ends cut and tested. The average Ic of all cable pieces tested was 2990 A ± 10% in self field. The bending strain of Rutherford cables with a ceramic coated Ni-alloy core showed little or no degradation up to 6%. In contrast, cables manufactured without a Ni-alloy core showed critical bending strains of about 2%.

We developed a new strong Rutherford cable using Bi 2 Sr 2 CaCu 2 O y (Bi-2212) high temperature superconducting (HTS) wire, which consisted of 427 superconducting filaments and AgMgSb alloy outer sheath. This wire exhibited excellent critical current (I c ) and critical current density (J c ) values at 4.2 K in self-field (285 A and 340000 A/cm 2 , respectively) and a room temperature tensile strength of 180 MPa. The Rutherford cable was prepared with a NiCr alloy strip as a cable core. The degradation of full cable I c induced by Ni diffusion was reduced by introducing a ceramic barrier layer between the Bi-2212 superconducting wires and the NiCr cable core. A full cable I c value of 3500 A at 4.2 K in self-field was obtained in short sample fabricated by using a cable core with a ZrO 2 film barrier layer. Finally, we fabricated an 80-m-long Rutherford cable by using a cable core with a MgO tape as a barrier layer and evaluated its full cable I c . I c values of 17-m-long sections cut from a continuous 80-m-long cable were greater than 2700 A at 4.2 K in self-field.

A stacked pancake coil was fabricated by Ag-alloy sheathed Bi-2212 multilayer tapes and tested using a refrigerator. The magnet consisted of ten double pancakes wound with 100 m class tapes. The I/sub c/ values of the tapes varied from 80 A to 150 A at 4.2 K and 10 T because of the scattering of the thickness in the superconducting layers. The magnet carried a critical current of 57 A at 12 K and generated B/sub max/ of 1.4 T in a 60 mm bore. At 12 K, the magnet could operate with an operating current of 45 A which corresponded to about 80% of I/sub c/. Thermal runaway was not observed even with a ramp rate of 10 T/min.

A tritium separation from heavy water by electrolysis using a solid polymer electrode layer was specified. The cathode was made of stainless steel or nickel. The electrolysis was performed for 1 hour at 5, 10, 20, and 30 °C. Using a palladium catalyst, generated hydrogen and oxygen gases were recombined, which was collected with a cold trap. The activities of the samples were measured by a liquid scintillation counter. The apparent tritium separation factors of the heavy and light water at 20 °C were ∽2 and ∽12, respectively.

Hole transport properties of organic light‐emitting diodes (OLEDs) with a thin hole‐blocking layer (HBL) were evaluated by time‐of‐flight measurement. Electroluminescence (EL) spectra of OLEDs with various HBL thicknesses were also evaluated. The results clearly show that the time‐resolved photocurrent response and the emission color strongly depend on HBL thickness. This can be attributed to hole‐tunneling through the thin HBL. We successfully fabricated a white OLED by controlling the thickness of HBL.

An energy supply system for initial manned lunar bases was studied. A 300 kWe plant was considered combining a liquid metal fast reactor with a potassium Rankine cycle. The reactor vessel is buried under ground and a regolith layer works as shielding. The settling and starting procedures on the Moon are also discussed.

Step bunching of vicinal GaN(0001) surface during epitaxial growth is observed by scanning tunneling microscopy. Large step stiffness and repulsive step-step interaction are suggested based on step morphology observations. The size of the bunch changes with time, depending on the direction in which the substrate is heated by a direct current. This observation provides evidence for the electromigration effect causing the step bunching, and from the field dependence we infer that adatoms, which are likely N, have effective positive charges.

Continuous-wave laser operation at wavelengths of over 1.3-/spl mu/m at room temperature was successfully demonstrated using an edge-emitting Sb-based InGaSb quantum dot laser diode (QD-LD) and an InGaSb-QD vertical-cavity surface-emitting laser (QD-VCSEL) fabricated on GaAs substrates.

At the Wakasa Wan Energy Research Center (WERC), we had constructed an accelerator system with a 5 MV tandem accelerator and a 200 MeV proton synchrotron. The tandem machine has 5 beam lines for the MeV order beam experiments. Also the tandem beam is injected to the synchrotron. The beam accelerated by the synchrotron is used at three experimental beam lines. After the completion of the construction in 2000, we have been performing experiments using the system for the ion beam analyses (RBS, ERDA, PIXE) and irradiations for the material and biological sciences. In 2002, the study of the cancer therapy with a proton beam from the synchrotron was started. In this paper, the layout of the accelerator facility, recent development for the accelerators and experiments will be reported.

At Wakasa-wan Energy Research Center, Fukui, Japan, the accelerator system is now under construction. The system consists of a 200 keV ion implanter, a 5 MV Schenckel type tandem accelerator and a 200 MeV proton synchrotron. The ion implanter is for the improvement of the surface of the material. By using the tandem accelerator, we can perform the element analysis, the improvement of the bio-species and ion-implantation into various materials. The tandem accelerator works as an injector for the synchrotron and the synchrotron is for the cancer therapy and also bio and material science.

This paper concerns the development of a digital PCM current differential relay for transmission line. The developed relay has an automatic synchronization function and its interface to digital multiplex equipment is designed according to CCITT recommendation G.703 co-directional interface. And also to improve the communication reliability, this relay can be connected to duplicate communication channels with automatic changeover from main to stand-by channel in case of failure of main channel. Detection of communication channel failure is fulled up by built-in CRC (cyclic redundancy check), fixed bit check, frame synchronism check and, etc. Two 16 bits microprocessors, one is for current differential calculations and another is for data transmission functions, can construct the full relay function. The relay has been tested by digital simulated fault currents which were calculated by EMTP (Electro-magnetic transient program) for a large capacitive cable line.

This paper concerns the development of a digital PCM current differential relay for transmission line. The developed relay has an automatic synchronization function and its interface to digital multiplex equipment is designed according to CCITT recommendation G.703 co-directional interface. And also to improve the communication reliability, this relay can be connected to duplicate communication channels with automatic changeover from main to stand-by channel in case of failure of main channel. Detection of communication channel failure is fulled up by built-in CRC (cyclic redundancy check), fixed bit check, frame synchronism check and, etc. Two 16 bits microprocessors, one is for current differential calculations and another is for data transmission functions, can construct the full relay function. The relay has been tested by digital simulated fault currents which were calculated by EMTP (Electro-magnetic transient program) for a large capacitive cable line.