IPAC2017 - List of Authors (Aumon, S.)

Paper	Title	Page
MOPIK097	Vertical Dispersion and Betatron Coupling Correction for FCC-ee	752
	S. Aumon, B.J. Holzer CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK097
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WEPIK031	Challenges and Status of the Rapid Cycling Top-Up Booster for FCC-ee	2996
	B. Härer, S. Aumon, B.J. Holzer, Y. Papaphilippou, T. Tydecks CERN, Geneva, Switzerland K. Oide KEK, Ibaraki, Japan
	FCC-ee is a 100 km e⁺ e⁻ collider, which is being designed within the Future Circular Collider Study (FCC) for precision studies and rare decay observations in the range of 90 to 350 GeV center-of- mass energy. The beam lifetime will be limited to less than one hour, because of radiative Bhaba scattering and beamstrahlung. In order to keep the luminosity on the high level of 10³⁵ cm^-2s^-1 continuous top-up injection is required. Therefore, besides the collider, that will operate at constant energy, a fast cycling booster synchrotron will be installed in the tunnel. The injection energy to the booster synchrotron will be around 6-20 GeV. Such a small energy together with the large bending radius not only creates an ultra-small beam emittance, but also requires very low magnetic fields close to the limit of technical feasibility. This paper will focus on the challenges and requirements for the top-up booster design arising from low magnetic fields and collective instabilities and present the status of the lattice design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK031
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Vertical Dispersion and Betatron Coupling Correction for FCC-ee

752

S. Aumon, B.J. Holzer
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

The FCC-ee project foresees to build a 100 km e⁺/e⁻ circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 10³⁵ cm^-2s^-1. To reach such performances, an extreme focusing of the beam is required in the interaction regions with a low vertical beta function of 2~mm at the IPs. Moreover, the FCC-ee physics program requires very low emittances never achieved in a collider with 1~nm for ε_x and 2~pm for ε_y, bringing down the coupling ratio to 2/1000. Thus, coupling and vertical dispersion sources have to be controlled carefully. This paper describes the tolerance of the machine to magnet alignment errors as well as the optics correction methods that were implemented, such as the Orbit Dispersion Free Steering, in order to bring the vertical dispersion to reasonable values. The correction of the betatron coupling, being also a very important source of emittance growth, has been integrated to a challenging correction scheme to keep the vertical emittance as low as possible.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK097

Export •

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

WEPIK031

Challenges and Status of the Rapid Cycling Top-Up Booster for FCC-ee

2996

B. Härer, S. Aumon, B.J. Holzer, Y. Papaphilippou, T. Tydecks
CERN, Geneva, Switzerland
K. Oide
KEK, Ibaraki, Japan

FCC-ee is a 100 km e⁺ e⁻ collider, which is being designed within the Future Circular Collider Study (FCC) for precision studies and rare decay observations in the range of 90 to 350 GeV center-of- mass energy. The beam lifetime will be limited to less than one hour, because of radiative Bhaba scattering and beamstrahlung. In order to keep the luminosity on the high level of 10³⁵ cm^-2s^-1 continuous top-up injection is required. Therefore, besides the collider, that will operate at constant energy, a fast cycling booster synchrotron will be installed in the tunnel. The injection energy to the booster synchrotron will be around 6-20 GeV. Such a small energy together with the large bending radius not only creates an ultra-small beam emittance, but also requires very low magnetic fields close to the limit of technical feasibility. This paper will focus on the challenges and requirements for the top-up booster design arising from low magnetic fields and collective instabilities and present the status of the lattice design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK031

Export •

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