eeFACT2018 - List of Keywords (ECR)

Paper	Title	Other Keywords	Page
TUYBA02	Beam-beam Effects at High Energy e⁺e⁻ Colliders	luminosity, resonance, betatron, collider	106
	D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Russian Science Foundation, project N14-50-00080. One of the main requirements for future e⁺e⁻ colliders is high luminosity. If the energy per beam does not exceed 200 GeV, the optimal choice will be a circular collider with "crab waist" collision scheme. Here, to achieve maximum luminosity, the beams should have a very high density at the IP. For this reason, radiation in the field of a counter bunch (BS - beamstrahlung) becomes an appreciable factor affecting the dynamics of particles. In particular, in the simulation for FCC-ee, new phenomena were discovered: 3D flip-flop and coherent X-Z instability. The first is directly related to BS. The second can manifest itself at low energy (where BS is negligible), but at high energies BS substantially changes the picture. In the example of FCC-ee, we will consider the features of beam-beam interaction at high-energy crab waist colliders, and optimization of parameters for high luminosity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA02
About •	paper received ※ 19 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPBB04	Resonant Depolarization at Z and W at FCC-ee	synchrotron, polarization, resonance, collider	165
	I. Koop BINP SB RAS, Novosibirsk, Russia
	Both future 100 km in circumference electron-positron colliders CEPC and FCC-ee need know beams energies with the extreme precision of 1-2 ppm. This can be done only with the help of Resonant Depolarization (RD) technique. Still, some beam parameters of these machines, like energy spread and damping decrements, are so high near 80 GeV per beam, that it is required special consideration and tricks to overcome the difficulties. The author has written simple spin tracking code, which simulates main features of the RD process in presence of continuous energy diffusion due to synchrotron radiation fluctuations. It was shown by this study, that the applicability of the RD method is limited by the effect of widening of a width of the central peak of the spin precession spectrum when the synchrotron tune is chosen too low, say below 0.05. In this case spin precession lost its resonant nature due to overlap of the wide central spectrum peak with nearby synchrotron side bands. Dependencies of the spectrum peaks width from various beam parameters and a new RD-procedure recipe are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB04
About •	paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUYBA02

Beam-beam Effects at High Energy e⁺e⁻ Colliders

luminosity, resonance, betatron, collider

106

D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Russian Science Foundation, project N14-50-00080.
One of the main requirements for future e⁺e⁻ colliders is high luminosity. If the energy per beam does not exceed 200 GeV, the optimal choice will be a circular collider with "crab waist" collision scheme. Here, to achieve maximum luminosity, the beams should have a very high density at the IP. For this reason, radiation in the field of a counter bunch (BS - beamstrahlung) becomes an appreciable factor affecting the dynamics of particles. In particular, in the simulation for FCC-ee, new phenomena were discovered: 3D flip-flop and coherent X-Z instability. The first is directly related to BS. The second can manifest itself at low energy (where BS is negligible), but at high energies BS substantially changes the picture. In the example of FCC-ee, we will consider the features of beam-beam interaction at high-energy crab waist colliders, and optimization of parameters for high luminosity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA02

About •

paper received ※ 19 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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

TUPBB04

Resonant Depolarization at Z and W at FCC-ee

synchrotron, polarization, resonance, collider

165

I. Koop
BINP SB RAS, Novosibirsk, Russia

Both future 100 km in circumference electron-positron colliders CEPC and FCC-ee need know beams energies with the extreme precision of 1-2 ppm. This can be done only with the help of Resonant Depolarization (RD) technique. Still, some beam parameters of these machines, like energy spread and damping decrements, are so high near 80 GeV per beam, that it is required special consideration and tricks to overcome the difficulties. The author has written simple spin tracking code, which simulates main features of the RD process in presence of continuous energy diffusion due to synchrotron radiation fluctuations. It was shown by this study, that the applicability of the RD method is limited by the effect of widening of a width of the central peak of the spin precession spectrum when the synchrotron tune is chosen too low, say below 0.05. In this case spin precession lost its resonant nature due to overlap of the wide central spectrum peak with nearby synchrotron side bands. Dependencies of the spectrum peaks width from various beam parameters and a new RD-procedure recipe are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB04

About •

paper received ※ 12 October 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019

Export •

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