FEL2012 - List of Authors (Kuroda, R.)

Paper	Title	Page
MOPD57	Development of Multi-bunch Laser System for Photocathode RF Gun in KU - FEL	173
	K. Shimahashi, Y.W. Choi, H. Imon, T. Kii, R. Kinjo, T. Konstantin, K. Masuda, H. Negm, H. Ohgaki, K. Okumura, M. Omer, S. Shibata, K. Yoshida, H. Zen Kyoto University, Institute for Advanced Energy, Kyoto, Japan R. Kuroda AIST, Tsukuba, Ibaraki, Japan
	We have been developing mid-infrared FEL (MIR-FEL) system, KU-FEL (Kyoto University-FEL), which utilizes a 4.5-cell S-band thermionic RF gun, in Institute of Advanced Energy, Kyoto University. We plan to introduce a BNL-type 1.6-cell photocathode RF gun to generate higher peak power MIR-FEL. The purpose of this work is to develop the multi-bunch laser system which excites the photocathode in the RF gun. The target values of the system are bunch number of 300 and pulse energy of 10　uJ perμpulse in 266 nm. The laser system consists of a mode-locked Nd:YVO4 laser as the oscillator, an acousto-optic modulator, a laser beam pointing stabilization system, a flash lamp pumped amplifier and 4th harmonic generation crystals. We will report the current status of multi-bunch laser in this conference.

THPD40	Femtosecond Electron Bunch Measurement using THz Cherenkov Radiation in Dielectric Materials	622
	J. Yang, K. Kan, T. Kondoh, K. Norizawa, A. Ogata, T. Toigawa, Y. Yoshida ISIR, Osaka, Japan M. Hangyo ILE Osaka, Suita, Japan H. Kobayashi KEK, Ibaraki, Japan R. Kuroda, H. Toyokawa AIST, Ibaraki, Japan
	A novel method of femtosecond electron bunch measurement has been proposed using THz Cherenkov radiation in dielectric materials. When the ultrashort electron beam moves to the dielectric materials, such as a hollow quartz tube covered by a metal, the electron induced coherent Cherenkov radiation is occurred as a frequency spectrum in THz range with discrete components (higher mode radiations). The intensities of the THz components and the width of the frequency spectrum are determined strictly by the bunch length. In the preliminary experiments, we succeeded to observe the THz Cherenkov radiation from a 200 fs electron bunch using mm-sized dielectric tubes. It was found that the radiation spectra are dependent on the bunch length. The higher mode radiations are appeared by decreasing the electron bunch length.

Paper

Title

Page

Development of Multi-bunch Laser System for Photocathode RF Gun in KU - FEL

173

K. Shimahashi, Y.W. Choi, H. Imon, T. Kii, R. Kinjo, T. Konstantin, K. Masuda, H. Negm, H. Ohgaki, K. Okumura, M. Omer, S. Shibata, K. Yoshida, H. Zen
Kyoto University, Institute for Advanced Energy, Kyoto, Japan
R. Kuroda
AIST, Tsukuba, Ibaraki, Japan

We have been developing mid-infrared FEL (MIR-FEL) system, KU-FEL (Kyoto University-FEL), which utilizes a 4.5-cell S-band thermionic RF gun, in Institute of Advanced Energy, Kyoto University. We plan to introduce a BNL-type 1.6-cell photocathode RF gun to generate higher peak power MIR-FEL. The purpose of this work is to develop the multi-bunch laser system which excites the photocathode in the RF gun. The target values of the system are bunch number of 300 and pulse energy of 10　uJ perμpulse in 266 nm. The laser system consists of a mode-locked Nd:YVO4 laser as the oscillator, an acousto-optic modulator, a laser beam pointing stabilization system, a flash lamp pumped amplifier and 4th harmonic generation crystals. We will report the current status of multi-bunch laser in this conference.

THPD40

Femtosecond Electron Bunch Measurement using THz Cherenkov Radiation in Dielectric Materials

622

J. Yang, K. Kan, T. Kondoh, K. Norizawa, A. Ogata, T. Toigawa, Y. Yoshida
ISIR, Osaka, Japan
M. Hangyo
ILE Osaka, Suita, Japan
H. Kobayashi
KEK, Ibaraki, Japan
R. Kuroda, H. Toyokawa
AIST, Ibaraki, Japan

A novel method of femtosecond electron bunch measurement has been proposed using THz Cherenkov radiation in dielectric materials. When the ultrashort electron beam moves to the dielectric materials, such as a hollow quartz tube covered by a metal, the electron induced coherent Cherenkov radiation is occurred as a frequency spectrum in THz range with discrete components (higher mode radiations). The intensities of the THz components and the width of the frequency spectrum are determined strictly by the bunch length. In the preliminary experiments, we succeeded to observe the THz Cherenkov radiation from a 200 fs electron bunch using mm-sized dielectric tubes. It was found that the radiation spectra are dependent on the bunch length. The higher mode radiations are appeared by decreasing the electron bunch length.