IPAC2017 - List of Authors (Kako, E.)

Paper	Title	Page
MOPVA019	60 pC Bunch Charge Operation of the Compact ERL at KEK	890
	T. Miyajima, K. Harada, Y. Honda, E. Kako, R. Kato, T. Miura, N. Nakamura, T. Obina, M. Shimada, R. Takai, K. Umemori, M. Yamamoto KEK, Ibaraki, Japan R. Hajima, R. Nagai QST, Tokai, Japan T. Hotei Sokendai, Ibaraki, Japan N. Nishimori Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	The compact ERL (cERL) at KEK was operated in March 2017 to demonstrate generation, acceleration and transportation of the target bunch charge of 60 pC without energy recovery. However, the maximum bunch charge was limited to 40 pC due to the limitation of the excitation laser power. For the bunch charge of 40 pC, the bunch length and the normalized emittance were measured in the injector diagnostic line. The results of the bunch length measurement gave good agreement with the values that had been obtained by model simulation. The measured normalized rms emittances for 40 pC were 0.9 to 2.4 mm mrad, and they were lager than the design value of 0.6 mm mrad. To achieve the design emittance, we have studied the source of the emittance growth for the bunch charge of 40 pC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA019
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MOPVA073	Development of Peak Hold Module for Electron Emission in STF-Type Power Coupler for the ILC	1034
	Y. Yamamoto, E. Kako, T. Shishido KEK, Ibaraki, Japan
	In STF, the RF conditioning for power coupler is done in several steps from 10 to 1650 μs as specified in TDR for the ILC. The most important signals during the RF conditioning are vacuum level, and electron emission by multipacting. The vacuum level changes continuously, and electron emission has pulse-like behavior, which has much faster response. Therefore, it was necessary to develop the peak hold and isolation modules to evaluate electron emission in short pulse width. This module has two kinds of feature. One is pulse height detection, and the other is total charge detection (integrated signal). During the RF conditioning for power couplers in STF-2 cryomodule, this module perfectly worked, and detected different trend between the pulse height and the total charge. In this paper, the detailed result for the peak hold module will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA073
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TUPAB006	Achievement of Stable Pulsed Operation at 31 MV/m in the STF-2 Cryomodule for the ILC	1308
	Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, N. Kota, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori KEK, Ibaraki, Japan
	In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomodule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities, which was used for Quantum Beam Project in 2012, was successfully done. The main purpose is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification, and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. During 8 cavities operation, piezo actuators were used for the compensation of LFD, and the feed-forward and vector-sum control system by LLRF worked perfectly for keeping the lowest forward power and the stable flat-top of accelerating gradient. In this paper, the result for the STF-2 cryomodule in the 3rd cooldown test will be presented in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB006
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Paper

Title

Page

60 pC Bunch Charge Operation of the Compact ERL at KEK

890

T. Miyajima, K. Harada, Y. Honda, E. Kako, R. Kato, T. Miura, N. Nakamura, T. Obina, M. Shimada, R. Takai, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai
QST, Tokai, Japan
T. Hotei
Sokendai, Ibaraki, Japan
N. Nishimori
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

The compact ERL (cERL) at KEK was operated in March 2017 to demonstrate generation, acceleration and transportation of the target bunch charge of 60 pC without energy recovery. However, the maximum bunch charge was limited to 40 pC due to the limitation of the excitation laser power. For the bunch charge of 40 pC, the bunch length and the normalized emittance were measured in the injector diagnostic line. The results of the bunch length measurement gave good agreement with the values that had been obtained by model simulation. The measured normalized rms emittances for 40 pC were 0.9 to 2.4 mm mrad, and they were lager than the design value of 0.6 mm mrad. To achieve the design emittance, we have studied the source of the emittance growth for the bunch charge of 40 pC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA019

Export •

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

MOPVA073

Development of Peak Hold Module for Electron Emission in STF-Type Power Coupler for the ILC

1034

Y. Yamamoto, E. Kako, T. Shishido
KEK, Ibaraki, Japan

In STF, the RF conditioning for power coupler is done in several steps from 10 to 1650 μs as specified in TDR for the ILC. The most important signals during the RF conditioning are vacuum level, and electron emission by multipacting. The vacuum level changes continuously, and electron emission has pulse-like behavior, which has much faster response. Therefore, it was necessary to develop the peak hold and isolation modules to evaluate electron emission in short pulse width. This module has two kinds of feature. One is pulse height detection, and the other is total charge detection (integrated signal). During the RF conditioning for power couplers in STF-2 cryomodule, this module perfectly worked, and detected different trend between the pulse height and the total charge. In this paper, the detailed result for the peak hold module will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA073

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

TUPAB006

Achievement of Stable Pulsed Operation at 31 MV/m in the STF-2 Cryomodule for the ILC

1308

Y. Yamamoto, T. Dohmae, M. Egi, K. Hara, T. Honma, E. Kako, Y. Kojima, T. Konomi, N. Kota, T. Kubo, T. Matsumoto, T. Miura, H. Nakai, K. Nakanishi, G.-T. Park, T. Saeki, H. Shimizu, T. Shishido, T. Takenaka, K. Umemori
KEK, Ibaraki, Japan

In the Superconducting RF Test Facility (STF) in KEK, the cooldown test for the STF-2 cryomodule with 12 cavities has been done totally three times since 2014. In 2016, the 3rd cooldown test for the STF-2 cryomodule including the capture cryomodule with 2 cavities, which was used for Quantum Beam Project in 2012, was successfully done. The main purpose is the vector-sum operation with 8 cavities at average accelerating gradient of 31 MV/m as the ILC specification, and the others are the measurement for Lorenz Force Detuning (LFD) and unloaded Q value, and Low Level RF (LLRF) study, etc. During 8 cavities operation, piezo actuators were used for the compensation of LFD, and the feed-forward and vector-sum control system by LLRF worked perfectly for keeping the lowest forward power and the stable flat-top of accelerating gradient. In this paper, the result for the STF-2 cryomodule in the 3rd cooldown test will be presented in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPAB006

Export •

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