eeFACT2016 - Table of Session: TUT2H (Injector and Beam Injection)

Paper	Title	Page
TUT2H1	Top-up Injection for a Future Electro-positron Collider	66
	J.T. Seeman SLAC, Menlo Park, California, USA
	Funding: Work Supported under US DOE/SU Contract DE-AC02-76SF00515. The schemes for full-energy top-up injection into an e⁺e⁻ collider will be discussed emphasizing technical issues to be accommodated. The issues include energy stability, energy spread control, transverse emittance reduction, transverse position and angle stability, collimation, background control in the detector, detector blanking of event triggers, and bunch filling strategies. Strategies and observations from PEP-II and KEKB will be included.
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TUT2H2	Injector Linac Upgrade and New RF Gun Development for SuperKEKB	74
	T. Natsui, D. Satoh, M. Yoshida, R. Zhang, X. Zhou KEK, Ibaraki, Japan
	The SuperKEKB commissioning has finally started. The final goal of luminosity is 40 times higher than KEKB. The injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance of the SuperKEKB ring. In the injector linac, several new instruments have been installed. Flux Concentrator (FC) was developed for high charge positron beam production. The target bunch charge of positron beam is 4 nC. The new damping ring will be used for positron beam to reduce beam emittance to 10 mm-mrad. However, electron beam must be reached to 20 mm-mrad normalized emittance at 5 nC beam charge without damping ring. Thermionic gun was used for KEKB injector and it was able to generate enough beam charge. However, its emittance is too large. Therefor we developed photo cathode S-band RF gun. This new RF gun has unique accelerating cavity which called quasi-travelling wave side coupled cavity. Laser system for this photo cathode has been also developed. The laser system is constructed with Yb:YAG thin disk for high power and pulse shaping. I will illustrate the RF gun, laser system and several new injector linac systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H2
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TUT2H3	Design study of CEPC Booster	79
	T.J. Bian, X. Cui, J. Gao, B. Sha, D. Wang, Y. Wang, M. Xiao, C. Zhang IHEP, Beijing, People's Republic of China Y. Cai SLAC, Menlo Park, California, USA M. Koratzinos DPNC, Genève, Switzerland F. Su Institute of High Energy Physics (IHEP), People's Republic of China
	Funding: Work supported by National Natural Science Foundation of China, Grant No. NSFC 11575218 and No. 11505198 CEPC is next generation circular collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120GeV, but the injected beam only 6GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. we have two ways to solve this problem, Firstly, we propose to operate the booster ring as a large wiggler at low beam energy and as a normal ring at high energies to avoid the problem of very low dipole magnet fields. Secondly, we implement the orbit correction and correct the earth field to make booster work.
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TUT2H4	Top-up Injection Schemes for HEPS	85
	Z. Duan, J. Chen, Y. Jiao, Y.M. Peng, Q.Y. Wang, G. Xu, P. Zhang IHEP, Beijing, People's Republic of China
	Funding: Natural Science Foundation of China (No.11605212) Top-up injection has become standard mode of operation for most third generation light sources, and has also been suc- cesfully applied in electron-positron circular colliders like KEKB and PEP-II. For next generation ultra-low emittance storage rings approaching the diffraction limit of X-rays, take the High Energy Photon Source (HEPS) for example, top-up injection is a basic requirement but non-trivial to im- plement. The very small dynamic aperture is insufficient for traditional off-axis injection scheme, instead, a novel on-axis injection scheme was recently proposed for HEPS, based on RF gymnastics of a double-frequency RF system. This paper will describe the physical mechanism of this scheme, related RF issues, and the implications for top-up injection.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H4
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TUT2H5	Towards a Preliminary FCC-ee Injector Design	90
	S. Ogur, Y. Papaphilippou, F. Zimmermann CERN, Geneva, Switzerland A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia K. Furukawa, N. Iida, F. Miyahara, K. Oide KEK, Ibaraki, Japan
	The Future Circular Collider-ee aims to get high luminosity which mainly relies upon high charge and low geometric emittance in the collider. The FCC-ee is a future project of CERN to operate as Z, W, H and tt factories with varying energies between 45.6 to 175 GeV. Among those, the total charge requirement is peaked for Z-operation (i.e. 91500 bunches of electron and positron with 3.3·10¹⁰ particles per bunch) meanwhile this mode targets the smallest geometric emittance in the Collider. To reach the goal, the normal conducting S-band Linac has been designed to accelerate 4·10¹⁰ particles in a bunch to 6 GeV and send two bunches per RF pulse within a repetition of 100 Hz. The FCC-ee positrons will also be created inside the linac at 4.46 GeV and accelerated to 1.54 GeV. These positrons are damped at the designed Damping Ring at that energy, and then transferred back to the Linac to meet the same characteristics of electrons. Therefore, in this paper, we'd like to discuss the transmission and robustness of the Linac and the dynamic aperture of the Damping Ring which has to be large enough to accept the incoming beam and cover the probable shrink due to the misalignments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H5
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TUT2H6	Electron Sources and Polarization	94
	R. Xiang, J. Teichert HZDR, Dresden, Germany
	Funding: Supported by the European Community under the FP7 programme (EuCARD-2 and LA3NET) and by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1. In this presentation the present electron sources and the relevant issues will be discussed. For the electron positron colliders and accelerator based light sources, the electron gun and injector design, are arguably the most critical part. There are a variety of electron source designs: DC guns, normal-conducting RF guns, superconducting RF gun and hybrid guns. All variants have their own ad-vantages and difficulties. We will overview the typical sources around the world, and compare their advantages and main challenges. The polarization production will also be discussed.
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Paper

Title

Page

Top-up Injection for a Future Electro-positron Collider

66

J.T. Seeman
SLAC, Menlo Park, California, USA

Funding: Work Supported under US DOE/SU Contract DE-AC02-76SF00515.
The schemes for full-energy top-up injection into an e⁺e⁻ collider will be discussed emphasizing technical issues to be accommodated. The issues include energy stability, energy spread control, transverse emittance reduction, transverse position and angle stability, collimation, background control in the detector, detector blanking of event triggers, and bunch filling strategies. Strategies and observations from PEP-II and KEKB will be included.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H1

Export •

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

TUT2H2

Injector Linac Upgrade and New RF Gun Development for SuperKEKB

74

T. Natsui, D. Satoh, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan

The SuperKEKB commissioning has finally started. The final goal of luminosity is 40 times higher than KEKB. The injector upgrade is required to obtain the low emittance and high charge beam corresponding to the short beam life and small injection acceptance of the SuperKEKB ring. In the injector linac, several new instruments have been installed. Flux Concentrator (FC) was developed for high charge positron beam production. The target bunch charge of positron beam is 4 nC. The new damping ring will be used for positron beam to reduce beam emittance to 10 mm-mrad. However, electron beam must be reached to 20 mm-mrad normalized emittance at 5 nC beam charge without damping ring. Thermionic gun was used for KEKB injector and it was able to generate enough beam charge. However, its emittance is too large. Therefor we developed photo cathode S-band RF gun. This new RF gun has unique accelerating cavity which called quasi-travelling wave side coupled cavity. Laser system for this photo cathode has been also developed. The laser system is constructed with Yb:YAG thin disk for high power and pulse shaping. I will illustrate the RF gun, laser system and several new injector linac systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H2

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TUT2H3

Design study of CEPC Booster

79

T.J. Bian, X. Cui, J. Gao, B. Sha, D. Wang, Y. Wang, M. Xiao, C. Zhang
IHEP, Beijing, People's Republic of China
Y. Cai
SLAC, Menlo Park, California, USA
M. Koratzinos
DPNC, Genève, Switzerland
F. Su
Institute of High Energy Physics (IHEP), People's Republic of China

Funding: Work supported by National Natural Science Foundation of China, Grant No. NSFC 11575218 and No. 11505198
CEPC is next generation circular collider proposed by China. The design of the full energy booster ring of the CEPC is especially challenging. The ejected beam energy is 120GeV, but the injected beam only 6GeV. In a conventional approach, the low magnetic field of the main dipole magnets creates problems. we have two ways to solve this problem, Firstly, we propose to operate the booster ring as a large wiggler at low beam energy and as a normal ring at high energies to avoid the problem of very low dipole magnet fields. Secondly, we implement the orbit correction and correct the earth field to make booster work.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H3

Export •

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TUT2H4

Top-up Injection Schemes for HEPS

85

Z. Duan, J. Chen, Y. Jiao, Y.M. Peng, Q.Y. Wang, G. Xu, P. Zhang
IHEP, Beijing, People's Republic of China

Funding: Natural Science Foundation of China (No.11605212)
Top-up injection has become standard mode of operation for most third generation light sources, and has also been suc- cesfully applied in electron-positron circular colliders like KEKB and PEP-II. For next generation ultra-low emittance storage rings approaching the diffraction limit of X-rays, take the High Energy Photon Source (HEPS) for example, top-up injection is a basic requirement but non-trivial to im- plement. The very small dynamic aperture is insufficient for traditional off-axis injection scheme, instead, a novel on-axis injection scheme was recently proposed for HEPS, based on RF gymnastics of a double-frequency RF system. This paper will describe the physical mechanism of this scheme, related RF issues, and the implications for top-up injection.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H4

Export •

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TUT2H5

Towards a Preliminary FCC-ee Injector Design

90

S. Ogur, Y. Papaphilippou, F. Zimmermann
CERN, Geneva, Switzerland
A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
K. Furukawa, N. Iida, F. Miyahara, K. Oide
KEK, Ibaraki, Japan

The Future Circular Collider-ee aims to get high luminosity which mainly relies upon high charge and low geometric emittance in the collider. The FCC-ee is a future project of CERN to operate as Z, W, H and tt factories with varying energies between 45.6 to 175 GeV. Among those, the total charge requirement is peaked for Z-operation (i.e. 91500 bunches of electron and positron with 3.3·10¹⁰ particles per bunch) meanwhile this mode targets the smallest geometric emittance in the Collider. To reach the goal, the normal conducting S-band Linac has been designed to accelerate 4·10¹⁰ particles in a bunch to 6 GeV and send two bunches per RF pulse within a repetition of 100 Hz. The FCC-ee positrons will also be created inside the linac at 4.46 GeV and accelerated to 1.54 GeV. These positrons are damped at the designed Damping Ring at that energy, and then transferred back to the Linac to meet the same characteristics of electrons. Therefore, in this paper, we'd like to discuss the transmission and robustness of the Linac and the dynamic aperture of the Damping Ring which has to be large enough to accept the incoming beam and cover the probable shrink due to the misalignments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H5

Export •

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

TUT2H6

Electron Sources and Polarization

94

R. Xiang, J. Teichert
HZDR, Dresden, Germany

Funding: Supported by the European Community under the FP7 programme (EuCARD-2 and LA3NET) and by the German Federal Ministry of Education and Research (BMBF) grant 05K12CR1.
In this presentation the present electron sources and the relevant issues will be discussed. For the electron positron colliders and accelerator based light sources, the electron gun and injector design, are arguably the most critical part. There are a variety of electron source designs: DC guns, normal-conducting RF guns, superconducting RF gun and hybrid guns. All variants have their own ad-vantages and difficulties. We will overview the typical sources around the world, and compare their advantages and main challenges. The polarization production will also be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2016-TUT2H6

Export •

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