Katsuji Emura

High-capacity electric double layer capacitor using three-dimensional porous current collector

A three-dimensional porous current collector made of a nickel-chromium alloy was developed based on foamed polyurethane. The foam-type substrate exhibited a high tolerance at high voltages in nonaqueous electrochemical systems. The electric double layer capacitor (EDLC) using the foam-type substrate exhibited stable charge/discharge behavior and showed a superior high-rate discharge capability as compared to an EDLC using the conventional aluminum foil. Furthermore, impedance analysis revealed an improved current collecting ability for the foam-type substrate. To improve the performance of EDLCs, a methodology that uses a three-dimensional current collector was described.

Superconducting storage ring NIJI‐III

NIJI‐III is a compact, superconducting storage ring dedicated for use in several commercial applications, especially x‐ray lithography. Assembly of the ring has been completed and NIJI‐III has been operating since August 1990. A beam current of above 450 mA was attained at an injection energy of 280 MeV. Currents of more than 200 mA can be accumulated at the final energy of 600 MeV.

NIJI-III Compact Superconducting Electron Storage Ring

The NIJI-III is a compact superconducting electron storage ring for industrial applications. Features of the ring include four strongly curved large-bore superconducting bending magnets utilizing quadrupole coils with a circular cross section surrounded by an air core and a cold bore. The circumference of the ring is 15.54 m with a critical wavelength of 13 A. Development of the NIJI-III is near completion. This report examines the design and performance of the NIJI-III.

Electron linac for both storage ring injection and free electron laser oscillation

Abstract We completed the electron linac which can operate in two modes: electron energy E of 100 MeV with macropulse duration τ of 1 μs for the storage-ring injection, and E =25 MeV with τ =10 μs for free-electron-laser (FEL) oscillation. Experimental results demonstrate the worlds first linac that succeeds in both the storage-ring injection and FEL oscillation.

Fast beam decay in an electron storage ring with low-energy injection

Abstract The phenomena of the fast beam decay which was often observed in electron storage rings with low-energy injection was studied. Drift motion of the trapped ions in the bending magnetic field was found to play an important role in the fast beam decay.

Operational performance of the NIJI-III superconducting storage ring

The operational performance of the NIJI-III superconducting storage ring has been studied with particular attention focused on the vacuum performance of the cold-bore chamber. Photon-stimulated gas desorption in the cold-bore chamber was examined after commissioning the storage ring. It was confirmed that the photon-stimulated gas desorption due to diffuse reflection of synchrotron radiation at the absorber was not dominant in the gas desorption when the electron beam was accumulated in the storage ring.

FEL oscillation in IR region using a two-mode compact linac

Abstract Free-electron-laser of (FEL) oscillation at 14 μm using a two-mode compact linac is reported. FEL oscillation with a net gain of 7% is obtained using an electron beam with an energy of 24.8 MeV, peak current of 30 A, and pulse duration of 10 μs. Since an electron beam with good properties such as a low emittance and narrow energy spread is essential for the FEL oscillation, a low-emittance gun supplied with a high voltage of DC −200 kV and a klystron modulator having a precise voltage stability were developed. The linac can not only be operated as a FEL source but also an injector for a synchrotron radiation ring. This is the first such linac reported and is expected to enable cost-effective industrial use of FEL.