NAPAC2016 - List of Authors (Urakawa, J.)

Paper	Title	Page
THPOA50	Development of an Optical Cavity for LCS Sources at the Compact ERL	1204
	T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan R. Hajima, M. Mori, R. Nagai, T. Shizuma QST, Tokai, Japan
	High-energy photons from the laser Compton scattering (LCS) sources are expected to be applied in various fields in a wide range photon energies from keV to GeV. High-flux and narrow-bandwidth LCS photon beam is realized in an energy recovery linac (ERL). An electron beam of high-average current and small-emittance collides with accumulating laser pulses in an enhancement cavity for generating high-flux LCS photon beam. We have developed the high-finesse bow-tie ring cavity for the LCS experiment at the Compact ERL (cERL) in KEK. In this presentation, we will report the detail of the optical cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA50
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THPOA51	Improvement of X-Ray Generation by Using Laser Compton Scattering in Laser Undulator Compact X-Ray Source(LUCX)	1207
	M.K. Fukuda, S. Araki, Y. Honda, Y. Sumitomo, N. Terunuma, J. Urakawa KEK, Ibaraki, 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 the laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. We have started to take X-ray images such as refraction contrast images and phase contrast imaging with Talbot interferometer. In this accelerator, 6-10keV X-rays are generated by LCS. An electron beam is produced by a 3.6cell RF-gun and accelerated to 18-24MeV by a 12cell accelerating tube. A laser pulse is stored in a 4-mirror planar optical cavity to enhance the power. To increase the flux of LCS X-rays, we perform an optimization of the beam-loading compensation, improvement of the intensity of an electron beam and a laser light at the collision point. We report the result of the X-ray generation in this accelerator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA51
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THPOA52	A Simulation for Bright THz Light Source from Wiggler Radiation at KEK LUCX	1210
	Y. Sumitomo, S. Araki, A. Aryshev, M.K. Fukuda, M. Shevelev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan A. Deshpande SAMEER, Mumbai, India N. Terunuma Sokendai, Ibaraki, 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 study a bright THz light source generated by a wiggler radiation at KEK LUCX THz experiment, where an injected four pre-micro-bunched electron beam with few hundreds femto-seconds separation plays a crucial role. The energy of pre-bunched beam reaches few MeV at an S-band 3.6 cell RF Gun, and hence the space-charge effect is not negligible. We simulate the beam optics by ASTRA code, a charged beam optics simulator with space-charge effect, and then the resultant particle distribution is passed to GENESIS, a FEL simulator to deal with the wiggler radiation. We also present an experimental result at KEK LUCX. The major advantage of this system is a compactness of total setup that is expected to generate a MW class peak power THz beam by the coherent radiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA52
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THPOA53	Luminosity Increase in Laser-Compton Scattering by Crab Crossing Method	1213
	Y. Koshiba, D. Igarashi, S. Ota, T. Takahashi, M. Washio RISE, Tokyo, Japan K. Sakaue Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan J. Urakawa KEK, Ibaraki, Japan
	In collider experiments such as KEKB, crab crossing method is a promising way to increase the luminosity and KEK (High Energy Accelerator Research Organization) has achieved the luminosity record in 2009. We are planning to apply crab crossing to laser-Compton scattering, which is a collision of electron beam and laser, to gain a higher luminosity leading to a higher brightness X-ray source. It is well known that the collision angle between electron beam and laser affects the luminosity. It is the best when the collision angle is zero, head-on collision, to get a higher luminosity but difficult to construct such system especially when using an optical cavity for laser. Concerning this difficulty, we are planning crab crossing by tilting the electron beam using an rf-deflector. Although crab crossing in laser-Compton scattering has been already proposed, nowhere has demonstrated yet. We are going to demonstrate and conduct experimental study at our compact accelerator system in Waseda University. In this conference, we will report about our compact accelerator system, laser system for laser-Compton scattering, and expected results of crab crossing laser-Compton scattering. V. Alessandro, et al. "Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators." Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA53
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Paper

Title

Page

Development of an Optical Cavity for LCS Sources at the Compact ERL

1204

T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
R. Hajima, M. Mori, R. Nagai, T. Shizuma
QST, Tokai, Japan

High-energy photons from the laser Compton scattering (LCS) sources are expected to be applied in various fields in a wide range photon energies from keV to GeV. High-flux and narrow-bandwidth LCS photon beam is realized in an energy recovery linac (ERL). An electron beam of high-average current and small-emittance collides with accumulating laser pulses in an enhancement cavity for generating high-flux LCS photon beam. We have developed the high-finesse bow-tie ring cavity for the LCS experiment at the Compact ERL (cERL) in KEK. In this presentation, we will report the detail of the optical cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA50

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THPOA51

Improvement of X-Ray Generation by Using Laser Compton Scattering in Laser Undulator Compact X-Ray Source(LUCX)

1207

M.K. Fukuda, S. Araki, Y. Honda, Y. Sumitomo, N. Terunuma, J. Urakawa
KEK, Ibaraki, 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 the laser Compton scattering(LCS) at Laser Undulator Compact X-ray source(LUCX) accelerator in KEK. We have started to take X-ray images such as refraction contrast images and phase contrast imaging with Talbot interferometer. In this accelerator, 6-10keV X-rays are generated by LCS. An electron beam is produced by a 3.6cell RF-gun and accelerated to 18-24MeV by a 12cell accelerating tube. A laser pulse is stored in a 4-mirror planar optical cavity to enhance the power. To increase the flux of LCS X-rays, we perform an optimization of the beam-loading compensation, improvement of the intensity of an electron beam and a laser light at the collision point. We report the result of the X-ray generation in this accelerator.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA51

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THPOA52

A Simulation for Bright THz Light Source from Wiggler Radiation at KEK LUCX

1210

Y. Sumitomo, S. Araki, A. Aryshev, M.K. Fukuda, M. Shevelev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan
A. Deshpande
SAMEER, Mumbai, India
N. Terunuma
Sokendai, Ibaraki, 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 study a bright THz light source generated by a wiggler radiation at KEK LUCX THz experiment, where an injected four pre-micro-bunched electron beam with few hundreds femto-seconds separation plays a crucial role. The energy of pre-bunched beam reaches few MeV at an S-band 3.6 cell RF Gun, and hence the space-charge effect is not negligible. We simulate the beam optics by ASTRA code, a charged beam optics simulator with space-charge effect, and then the resultant particle distribution is passed to GENESIS, a FEL simulator to deal with the wiggler radiation. We also present an experimental result at KEK LUCX. The major advantage of this system is a compactness of total setup that is expected to generate a MW class peak power THz beam by the coherent radiation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA52

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THPOA53

Luminosity Increase in Laser-Compton Scattering by Crab Crossing Method

1213

Y. Koshiba, D. Igarashi, S. Ota, T. Takahashi, M. Washio
RISE, Tokyo, Japan
K. Sakaue
Waseda University, Waseda Institute for Advanced Study, Tokyo, Japan
J. Urakawa
KEK, Ibaraki, Japan

In collider experiments such as KEKB, crab crossing method is a promising way to increase the luminosity and KEK (High Energy Accelerator Research Organization) has achieved the luminosity record in 2009. We are planning to apply crab crossing to laser-Compton scattering, which is a collision of electron beam and laser, to gain a higher luminosity leading to a higher brightness X-ray source. It is well known that the collision angle between electron beam and laser affects the luminosity. It is the best when the collision angle is zero, head-on collision, to get a higher luminosity but difficult to construct such system especially when using an optical cavity for laser. Concerning this difficulty, we are planning crab crossing by tilting the electron beam using an rf-deflector. Although crab crossing in laser-Compton scattering has been already proposed*, nowhere has demonstrated yet. We are going to demonstrate and conduct experimental study at our compact accelerator system in Waseda University. In this conference, we will report about our compact accelerator system, laser system for laser-Compton scattering, and expected results of crab crossing laser-Compton scattering.
*V. Alessandro, et al. "Luminosity optimization schemes in Compton experiments based on Fabry-Perot optical resonators." Physical Review Special Topics-Accelerators and Beams 14.3 (2011): 031001.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA53

Export •

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