IPAC2016 - List of Authors (Sakaue, K.)

Paper	Title	Page
THPOW057	Direct High Power Laser Diagnostic Technique on Focused Electron Bunch	4073
	D. Igarashi, A. Endo, K. Sakaue, T. Takahashi, M. Washio RISE, Tokyo, Japan
	In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efﬁciency and stable EUV power, we would like to measure a laser proﬁle in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing laser profiler based on laser Compton scattering(LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography. This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda university. We already succeeded in observing minimum beam size of about 20 μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW057
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MOPMB030	Development of an EO Sampling Method for THz Pulse Detection	155
	T. Toida, M. Washio, R. Yanagisawa Waseda University, Tokyo, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
	We have been studying an S-band Cs-Te photo-cathode rf gun at Waseda Univ. The high quality electron beam produced by the rf gun is used to generate a high-power coherent terahertz pulse via Cherenkov radiation. This terahertz pulse can be applied to terahertz imaging and material analysis. As a preliminary step towards material analysis, we conducted experiments on terahertz time domain spectroscopy by EO sampling method to reveal major parameters of the terahertz pulse such as the pulse form and the spectrum. EO sampling method has high frequency response and suitable for high peak power terahertz pulses. In terahertz time domain spectroscopy, the duration of the probe pulse needs to be much faster than that of the terahertz pulse. Therefore, we developed a mode locked Yb-fiber laser based on nonlinear polarization rotation as a reliable and cost-effective ultra-fast probe light source. The laser generates 3.80 ps chirped pulses which are compressed to 213 fs with a grating pair. In this conference, we will report the performance of the Yb-fiber laser and results of EO sampling experiments.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB030
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TUPOW046	Development and Upgrade Plan of an X-ray Source Based on Laser Compton Scattering in Laser Undulator Compact X-ray Source(LUCX)	1867
	M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan M. Kageyama, M. Kuribayashi Rigaku Corporation, XG & Core Technology, Tokyo, Japan A. Momose, M.P. Olbinado, Y. Wu Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan M. Washio RISE, Tokyo, Japan
	Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan. We have been developing a compact X-ray source based on Laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. Our aim is to obtain a clear X-ray image in a shorter period of times and the target number of X-ray is 1.7x10⁷ photons/pulse with 10% bandwidth. In the accelerator, an electron beam with the energy of 18-24 MeV is generated by an S-band normal conducting accelerator. The beam is collided with a laser pulse stacked in a 4-mirror planar optical cavity and then 6-10 keV X-rays are generated by LCS. Presently, the generation of X-rays with the number of 3x10⁶ photons/pulse at the collision point has been achieved. X-ray imaging test such as refraction contrast images and phase contrast imaging with Talbot interferometer has also started. To increase the intensity of X-rays, we are continuing the tuning of the electron beam and the optical cavity because the exposure time of X-ray imaging is too long now. We are also planning to increase the beam energy by appending the accelerating tube. In this conference, the recent results and upgrade plan in LUCX will be reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW046
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TUPOW047	Generation of a Coherent Cherenkov Radiation by using Electron Bunch Tilting	1870
	K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan R. Kuroda, Y. Taira AIST, Tsukuba, Japan M. Nishida, M. Washio Waseda University, Tokyo, Japan J. Urakawa KEK, Ibaraki, Japan
	We have been developing a compact accelerator based a laser photocathode rf electron gun at Waseda University. Low emittance and short bunched electron beam can be generated from the gun. Also, the rf transverse deflecting cavity was developed for the bunch length measurement. We performed an experiment for generating a coherent Cherenkov radiation using bunch tilting. The rf transverse deflector can give a tilt for the electron bunch, and the tilt angle was set to the Cherenkov radiating angle which determined by the target refractive index. We successfully demonstrated a coherent Cherenkov radiation and the characterization of the radiation. The principle of coherent Cherenkov radiation generation, the experimental results and future prospective will be presented at the conference.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW047
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Paper

Title

Page

Direct High Power Laser Diagnostic Technique on Focused Electron Bunch

4073

D. Igarashi, A. Endo, K. Sakaue, T. Takahashi, M. Washio
RISE, Tokyo, Japan

In laser produced plasma EUV source, high intensity pulse CO2 laser is essential for plasma generation. To achieve high conversion efﬁciency and stable EUV power, we would like to measure a laser proﬁle in the interaction point. However, there is no way to measure directly the laser profile of such a high intensity laser at the focus point. Therefore, we have been developing laser profiler based on laser Compton scattering(LCS). LCS signal by using focused electron beam shows 1D laser profile. 2D laser profile can be reconstructed by one-dimensional laser profiles from various angles using computer tomography. This method is suitable for high intensity laser, but very small spot size of electron beam is required. To obtain small spot size, we used S-band Cs-Te photocathode RF-Gun and specially designed solenoid lens at Waseda university. We already succeeded in observing minimum beam size of about 20 μm rms and this is adequate to scan the CO2 laser. In this conference, we will report the result of the laser Compton scattering with pulse CO2 laser, the preparatory experiment in measuring a metal wire cross section and the present progresses.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOW057

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MOPMB030

Development of an EO Sampling Method for THz Pulse Detection

155

T. Toida, M. Washio, R. Yanagisawa
Waseda University, Tokyo, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan

We have been studying an S-band Cs-Te photo-cathode rf gun at Waseda Univ. The high quality electron beam produced by the rf gun is used to generate a high-power coherent terahertz pulse via Cherenkov radiation. This terahertz pulse can be applied to terahertz imaging and material analysis. As a preliminary step towards material analysis, we conducted experiments on terahertz time domain spectroscopy by EO sampling method to reveal major parameters of the terahertz pulse such as the pulse form and the spectrum. EO sampling method has high frequency response and suitable for high peak power terahertz pulses. In terahertz time domain spectroscopy, the duration of the probe pulse needs to be much faster than that of the terahertz pulse. Therefore, we developed a mode locked Yb-fiber laser based on nonlinear polarization rotation as a reliable and cost-effective ultra-fast probe light source. The laser generates 3.80 ps chirped pulses which are compressed to 213 fs with a grating pair. In this conference, we will report the performance of the Yb-fiber laser and results of EO sampling experiments.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB030

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TUPOW046

Development and Upgrade Plan of an X-ray Source Based on Laser Compton Scattering in Laser Undulator Compact X-ray Source(LUCX)

1867

M.K. Fukuda, S. Araki, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
M. Kageyama, M. Kuribayashi
Rigaku Corporation, XG & Core Technology, Tokyo, Japan
A. Momose, M.P. Olbinado, Y. Wu
Tohoku University, Institute of Multidisciplinary Research for Advanced Materials, Sendai, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
M. Washio
RISE, Tokyo, Japan

Funding: This work was supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source based on Laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. Our aim is to obtain a clear X-ray image in a shorter period of times and the target number of X-ray is 1.7x10⁷ photons/pulse with 10% bandwidth. In the accelerator, an electron beam with the energy of 18-24 MeV is generated by an S-band normal conducting accelerator. The beam is collided with a laser pulse stacked in a 4-mirror planar optical cavity and then 6-10 keV X-rays are generated by LCS. Presently, the generation of X-rays with the number of 3x10⁶ photons/pulse at the collision point has been achieved. X-ray imaging test such as refraction contrast images and phase contrast imaging with Talbot interferometer has also started. To increase the intensity of X-rays, we are continuing the tuning of the electron beam and the optical cavity because the exposure time of X-ray imaging is too long now. We are also planning to increase the beam energy by appending the accelerating tube. In this conference, the recent results and upgrade plan in LUCX will be reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW046

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TUPOW047

Generation of a Coherent Cherenkov Radiation by using Electron Bunch Tilting

1870

K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
R. Kuroda, Y. Taira
AIST, Tsukuba, Japan
M. Nishida, M. Washio
Waseda University, Tokyo, Japan
J. Urakawa
KEK, Ibaraki, Japan

We have been developing a compact accelerator based a laser photocathode rf electron gun at Waseda University. Low emittance and short bunched electron beam can be generated from the gun. Also, the rf transverse deflecting cavity was developed for the bunch length measurement. We performed an experiment for generating a coherent Cherenkov radiation using bunch tilting. The rf transverse deflector can give a tilt for the electron bunch, and the tilt angle was set to the Cherenkov radiating angle which determined by the target refractive index. We successfully demonstrated a coherent Cherenkov radiation and the characterization of the radiation. The principle of coherent Cherenkov radiation generation, the experimental results and future prospective will be presented at the conference.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW047

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)