FCC-ee top-up injection

Name: FCC-ee top-up injection
Start: 2025-02-06T14:00:00+01:00
End: 2025-02-06T15:00:00+01:00
Location: No location set

Thursday 6 Feb 2025, 14:00 → 15:00 Europe/Zurich

66156014911

Yann Dutheil

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Present: C. Carli, Y. Dutheil, K. Keintzel, A. Lechner, T. Mori, G. Nigrelli, G. Roy, K. Skoufaris, R. Thomas, S. Yue

automatic summary here is inaccurate & misleading
Injection top-up baseline and MKI
- Baseline needs to remain on-axis to minimise noise to the experiments
- Present optics and MA does not allow on-axis for Z and W mode
  - Hybrid scheme allows to reduce the momentum offset at the expense of a betatron offset
  - W-mode baseline is hybrid
  - Z-mode with lower MA after beam-beam is added also requires hybrid
- Next steps
  - On-axis injection scheme study in LCC lattice
  - Compatible optics for both conventional and MKI injection
  - Requirements on the field distribution of MKI
  - Real threading of the beam trajectory upstream the injection point (F-quad)
Injection requirements
- Change at every energy mode since the equilibrium emittances increase with energy due to SR
- Present limitation comes from optics and MA, already a lot of effort put into DA/MA -> need to refocus on adjusting the optics for the injection scheme
- Presently keeping the 0.95% injection
Ring Optics & Technical Insertions
- Presently universal technical insertion for the all the SS : length and chromaticity are the same for all 4
- Ghislain will investigate the possibility of having special optics for each of the 4 straight sections
- Action Ghislain : will investigate the possibility of a new GHC lattice following requirements
  - (added after the discussion)
  - At injection point
    - Open physical space at the injection point of >5 m
    - Alpha_x and Dpx ~0
    - Beta_x = 1000 m and D_x = 1.8m
  - For conventional, bump injection
    - 2 kickers, pi/2 before and after the injection point
    - Same beta_x at each kicker
  - For MKI injection scheme
    - Non linear kicker needs compensation station with same kicker, but upstream the injection
    - Compensation primarily in horizontal, possible effect in vertical not discussed yet
    - compensation upstream with -I transform wrt the injection point
    - Compensation also with -Dx and -Dxp wrt the injection point
Giulia is working on the injection losses and background it may cause
- Presently on the Z-mode, with Kyriacos lattice
- Critical for experiments but presently no input from detectors on levels of acceptable losses
- Question of the scarping on the injection septum with conventional scheme, that could create background on the experiment
Existing collider injection repo
- https://gitlab.cern.ch/abt-optics-and-code-repository/projects/collider-injection-fcc-ee
- Repo contains tracking and phase-space plots, with submodules and lattice modifications needed to place the injection point
- Aims at ensuring everyone uses the same lattices, model and settings
- Aims at centralising the various contributions, either in-repo or linked sub-modules,

Actions

Action Ghislan and Rogelio : discussions within ABP to identify a primary contact to follow the beam dynamics/rings/collective effects aspects of top-up injection

09/01 organisation and chairing of the working group to be discussed after ABP main contact/s is/are identified

action Yann 09/01 add a conversion of Kevin's result for acceptable betatron offset of injected beam in number of sigma
Action Ghislain 06/02 : investigate the possibility of generating a new optics for the straight sections

There are minutes attached to this event. Show them.

- 1
  
  FCC-ee on-axis injection
  
  Speaker: Sen Yue
  
  FCC_MKI_topupinjection.pdf
  
  FCC_MKI_topupinjection.pptx

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FCC-ee top-up injection