IPAC2011 - List of Authors (Yamada, K.)

Paper	Title	Page
WEPZ027	Stabilization of the LWFA and its Application to the Single-shot K-edge Densitometry	2823
	K. Koyama, H. Madokoro, Y. Matsumura University of Tokyo, Tokyo, Japan R. Kuroda, K. Yamada AIST, Tsukuba, Ibaraki, Japan H. Masuda, M. Uesaka The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan S. Masuda Osaka University, Suita, Osaka, Japan
	Funding: This work was supported in part by Global COE Program “Nuclear Education and Research Initiative,” MEXT, Japan Injection of electrons into a laser wakefield accelerator (LWFA) via a wavebreaking process was investigated in order to obtain stable output of electron bunches. A density down ramp for occurring the wavebreaking was formed by an oblique shockwave, which was excited by setting a little flow-deflector on an edge of the supersonic nozzle of high-Mach number (M=5). Parameters of the jet were examined by using PIC code and evaluated by using an interferometer, the density was 10¹⁹cm^-3, density ratio was 2, and the characteristic length was 70 microns. Injection experiments using 7-TW laser pulses suggested that electrons were injected in the density ramp. Since the all-optical Compton X-ray is attractive source for an accurate densitometry, a preliminary experiment of a single-shot K-edge densitometry was performed by using X-ray pulses generated by the laser-Compton scattering (LCS) device based on a compact S-band 40 MeV linac at AIST. The single-shot K-edge densitometry was also applicable to evaluate the transverse emittance of electron bunches.

THPC118	Present Status of Quantum Radiation Sources on the Basis of the S-band Compact Electron Linac	3164
	R. Kuroda, E. Miura, H. Toyokawa, K. Yamada, E. Yamaguchi AIST, Tsukuba, Ibaraki, Japan M. Kumaki RISE, Tokyo, Japan
	We have developed quantum radiation sources such as a laser Compton scattering (LCS) X-ray and a coherent THz radiation sources on the basis of the S-band compact electron linac at AIST in Japan. The S-band linac consists of the laser-driven photocathode rf gun and two 1.5 m-long acceleration tubes and can accelerate the electron beam up to about 42 MeV. The LCS X-ray source can generate a quasi-monochromatic hard X-ray with variable energy of 12 - 40 keV for medical and biological applications. Now, the multi-collision LCS system has been developed with the regenerative amplifier type laser storage cavity and the multi-bunch electron beam to increase the X-ray yield. On the other hand, the high-power coherent THz radiation source has been also developed and its peak power is estimated to be more than 1 kW in frequency range between 0.1 - 2 THz. The high-power THz radiation was applied to the scanning transmission imaging. Now, the high power THz time domain spectroscopy (TDS) has been developed for the material science. In this conference, we will report the present status of the S-band compact electron linac, our quantum radiation sources and applications.

Paper

Title

Page

Stabilization of the LWFA and its Application to the Single-shot K-edge Densitometry

2823

K. Koyama, H. Madokoro, Y. Matsumura
University of Tokyo, Tokyo, Japan
R. Kuroda, K. Yamada
AIST, Tsukuba, Ibaraki, Japan
H. Masuda, M. Uesaka
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
S. Masuda
Osaka University, Suita, Osaka, Japan

Funding: This work was supported in part by Global COE Program “Nuclear Education and Research Initiative,” MEXT, Japan
Injection of electrons into a laser wakefield accelerator (LWFA) via a wavebreaking process was investigated in order to obtain stable output of electron bunches. A density down ramp for occurring the wavebreaking was formed by an oblique shockwave, which was excited by setting a little flow-deflector on an edge of the supersonic nozzle of high-Mach number (M=5). Parameters of the jet were examined by using PIC code and evaluated by using an interferometer, the density was 10¹⁹cm^-3, density ratio was 2, and the characteristic length was 70 microns. Injection experiments using 7-TW laser pulses suggested that electrons were injected in the density ramp. Since the all-optical Compton X-ray is attractive source for an accurate densitometry, a preliminary experiment of a single-shot K-edge densitometry was performed by using X-ray pulses generated by the laser-Compton scattering (LCS) device based on a compact S-band 40 MeV linac at AIST. The single-shot K-edge densitometry was also applicable to evaluate the transverse emittance of electron bunches.

THPC118

Present Status of Quantum Radiation Sources on the Basis of the S-band Compact Electron Linac

3164

R. Kuroda, E. Miura, H. Toyokawa, K. Yamada, E. Yamaguchi
AIST, Tsukuba, Ibaraki, Japan
M. Kumaki
RISE, Tokyo, Japan

We have developed quantum radiation sources such as a laser Compton scattering (LCS) X-ray and a coherent THz radiation sources on the basis of the S-band compact electron linac at AIST in Japan. The S-band linac consists of the laser-driven photocathode rf gun and two 1.5 m-long acceleration tubes and can accelerate the electron beam up to about 42 MeV. The LCS X-ray source can generate a quasi-monochromatic hard X-ray with variable energy of 12 - 40 keV for medical and biological applications. Now, the multi-collision LCS system has been developed with the regenerative amplifier type laser storage cavity and the multi-bunch electron beam to increase the X-ray yield. On the other hand, the high-power coherent THz radiation source has been also developed and its peak power is estimated to be more than 1 kW in frequency range between 0.1 - 2 THz. The high-power THz radiation was applied to the scanning transmission imaging. Now, the high power THz time domain spectroscopy (TDS) has been developed for the material science. In this conference, we will report the present status of the S-band compact electron linac, our quantum radiation sources and applications.