| Paper | Title | Page |
|---|---|---|
| TUYBA01 | Benchmarking of Simulations of Coherent Beam-beam Instability | 103 |
|
||
| Coherent beam-beam nstability in head-tail mode has been predicted in collision with a large crossing angle. The instability is serious for design of future e+e− colliders based on the large crossing angle collision. It is possible to observe the instability in SuperKEKB commissioning. Horizontal beam size blow-up of both beams has been seen depending on the tune operating point. We report the measurement results of the instability in SuperKEKB phaseII commissioning. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA01 | |
| About • | paper received ※ 25 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| TUYBA02 | Beam-beam Effects at High Energy e+e− Colliders | 106 |
|
||
|
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) | |
| TUYBA03 | Beam-beam Blowup in the Presence of x-y Coupling Sources for FCC-ee | 112 |
|
||
| FCC-ee, the lepton version of the Future Circular Collider (FCC), is a 100 Km future machine under study to be built at CERN. It acquires two experiments with a highest beam energy of 182.5 GeV. FCC-ee aims to operate at four different energies, with different luminosities to fulfill physics requirements. Beam-beam effects at such a high energy/luminosity machine are very challenging and require a deep understanding, especially in the presence of x-y coupling sources. Beam-beam effects include the beamstrahlung process, which limits the beam lifetime at high energies, as well as dynamic effects at the Interaction point (IP) which include changes in the beta functions and emittances. In this report, we will define the beam-beam effects and their behaviours in the FCC-ee highest energy lattice after introducing x-y coupling in the ring. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA03 | |
| About • | paper received ※ 11 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) | |
| TUYBA04 | Some Issues on Beam-beam Interaction at CEPC | 116 |
|
||
|
Funding: Project 11775238 supported by NSFC In this paper, the beam-beam study in CEPC CDR is briefly introduced. Some issues related with beam-beam interaction will be emphasized. The bunch lengthening due to impedance and beamstrahlung is simulated in a more self-consistent method. It is found that there exist very narrow stable working point space at W-mode during the CDR design study. We’ll show wider tune scan result. It is found that there exist some disagreement between dynamic aperture and beam lifetime. We try to define the so-called diffusion rate map to explain the cause. Some initial result for different lattice solution is shown. |
||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUYBA04 | |
| About • | paper received ※ 26 September 2018 paper accepted ※ 19 February 2019 issue date ※ 21 April 2019 | |
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
TUYBA05 |
Analytical Estimation of the Beam-beam Limited Dynamic Apertures and Liftimes | |
|
||
| In this paper, we will discuss analytical estimation of the beam beam limited dynamic aperture and lifetimes, which are very important for modern electron positron designs and operations, such as CEPC and FCCee, super Tau Charm factories, Super KEK B and BEPC-II, etc. This dicussion is in complementary to the beam beam limit discussion from the beam beam heating induced diffussion effect. The combination of the two effects from beam-beam interaction, i.e. nonlinear beam beam induced dynamic aperture limitation effect and the heating induced diffusion effect, makes the discussion of beam beam effect complete. | ||
| Export • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |