Tsuyoshi Shinzato

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.