IPAC2018 - List of Authors (Kuriki, M.)

Paper	Title	Page
MOPMF076	Energy Spread Compensation in Arbitrary Format Multi-Bunch Acceleration With Standing Wave and Traveling Wave Accelerators	307
	M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan
	In the E-driven ILC (International Linear Collider) positron source, the beam is generated and accelerated in a multi-bunch format with mini-trains. The macro-pulse contains 2 to 8 mini-trains with several train gaps, because the pulse format is a copy of a part of the bunch storage pattern in DR (Damping Ring). This pulse format causes a variation of the accelerator field in the pulse due to the transient beam loading and an intensity fluctuation of captured positron. In this article, we discuss the compensation of the energy spread of such beam in standing wave and traveling wave accelerators. For standing wave accelerator, it can be compensated by switching input RF at appropriate timings. For traveling wave accelerator, it can be compensated by amplitude modulation of the input RF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF076
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MOPMF077	A Design Study of the Electron-driven ILC Positron Source Including Beam Loading Effect	311
SUSPF003	use link to see paper's listing under its alternate paper code
	H. Nagoshi, M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Negishi Iwate University, Morioka, Iwate, Japan T. Omori, M. Satoh, Y. Seimiya, J. Urakawa KEK, Ibaraki, Japan Y. Sumitomo LEBRA, Funabashi, Japan T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	The International Linear Collider (ILC) is a next-generation accelerator for high-energy physics to study the Higgs and top sector in the Standard Model, and new physics such as supersymmetry and dark matter. ILC positron source based on Electron-driven method has been proposed as a reliable technical backup. In this article, we report the design study of the positron source based on the off-the-shelf RF components. The positron is generated and accelerated in a multi-bunch format. To compensate the energy variation by the transient beam loading effect, we employ AM (Amplitude Modulation) technique and the results were 16.60 ± 0.14 MV (peak-to-peak) for L-band 2m cavity driven by 22.5 MW power and 25.76 ± 0.19 MV (peak-to-peak) for S-band 2m ac-celerator driven by 36 MW power with 0.78 A beam load-ing.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF077
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THPMK116	NEA Surface Activation of GaAs Photocathode with CO2	4590
	L.Guo. Guo UVSOR, Okazaki, Japan H. Iijima Tokyo University of Science, Tokyo, Japan M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan K. Uchida Cosylab Japan, Ibaraki, Japan
	NEA (negative electron affinity)-GaAs cathode is able to generate highly spin polarized electron beam more than 90%. The NEA activation is performed usually with Cs and O2 or NF3, but the exact structure of the NEA surface is not known. In this paper, we performed the NEA activation on a cleaned GaAs surface with CO2, CO, N2, and O2 gases and compared the results to improve our understanding on the NEA surface. We found that CO2 activated the cathode, but N2 and CO did not. By analyzing CO2 activation, we found that atomic oxygen activates the NEA surface and CO degrades the NEA surface simultaneously. We found that the NEA activation ability of atomic oxygen is almost a half of that of O2 molecule.* *L. Guo, M. Kuriki, H. Iijima, K. Uchida. "NEA surface activation of GaAs photocathode with different gases", Surface Science 664C (2017) pp. 65-69.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK116
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Paper

Title

Page

Energy Spread Compensation in Arbitrary Format Multi-Bunch Acceleration With Standing Wave and Traveling Wave Accelerators

307

M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan

In the E-driven ILC (International Linear Collider) positron source, the beam is generated and accelerated in a multi-bunch format with mini-trains. The macro-pulse contains 2 to 8 mini-trains with several train gaps, because the pulse format is a copy of a part of the bunch storage pattern in DR (Damping Ring). This pulse format causes a variation of the accelerator field in the pulse due to the transient beam loading and an intensity fluctuation of captured positron. In this article, we discuss the compensation of the energy spread of such beam in standing wave and traveling wave accelerators. For standing wave accelerator, it can be compensated by switching input RF at appropriate timings. For traveling wave accelerator, it can be compensated by amplitude modulation of the input RF.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF076

Export •

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

MOPMF077

A Design Study of the Electron-driven ILC Positron Source Including Beam Loading Effect

311

SUSPF003

use link to see paper's listing under its alternate paper code

H. Nagoshi, M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Negishi
Iwate University, Morioka, Iwate, Japan
T. Omori, M. Satoh, Y. Seimiya, J. Urakawa
KEK, Ibaraki, Japan
Y. Sumitomo
LEBRA, Funabashi, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

The International Linear Collider (ILC) is a next-generation accelerator for high-energy physics to study the Higgs and top sector in the Standard Model, and new physics such as supersymmetry and dark matter. ILC positron source based on Electron-driven method has been proposed as a reliable technical backup. In this article, we report the design study of the positron source based on the off-the-shelf RF components. The positron is generated and accelerated in a multi-bunch format. To compensate the energy variation by the transient beam loading effect, we employ AM (Amplitude Modulation) technique and the results were 16.60 ± 0.14 MV (peak-to-peak) for L-band 2m cavity driven by 22.5 MW power and 25.76 ± 0.19 MV (peak-to-peak) for S-band 2m ac-celerator driven by 36 MW power with 0.78 A beam load-ing.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF077

Export •

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

THPMK116

NEA Surface Activation of GaAs Photocathode with CO2

4590

L.Guo. Guo
UVSOR, Okazaki, Japan
H. Iijima
Tokyo University of Science, Tokyo, Japan
M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan
K. Uchida
Cosylab Japan, Ibaraki, Japan

NEA (negative electron affinity)-GaAs cathode is able to generate highly spin polarized electron beam more than 90%. The NEA activation is performed usually with Cs and O2 or NF3, but the exact structure of the NEA surface is not known. In this paper, we performed the NEA activation on a cleaned GaAs surface with CO2, CO, N2, and O2 gases and compared the results to improve our understanding on the NEA surface. We found that CO2 activated the cathode, but N2 and CO did not. By analyzing CO2 activation, we found that atomic oxygen activates the NEA surface and CO degrades the NEA surface simultaneously. We found that the NEA activation ability of atomic oxygen is almost a half of that of O2 molecule.*
*L. Guo, M. Kuriki, H. Iijima, K. Uchida. "NEA surface activation of GaAs photocathode with different gases", Surface Science 664C (2017) pp. 65-69.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK116

Export •

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