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FCC-ee tuning meeting
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Europe/Zurich
FCC-ee tuning meeting
SuperKEKB reached 4.6e34 luminosity!
Oide-san, Outcome from recent events
Use all dipole trims for H correctors? -> cost versus performance.
V corrs only in QD? Study is needed to verify this.
Interference with neighboring magnets?
HTS SSS solves various issues of the design -> presentation from Mike in the tuning meeting.
Equiping magnets with movers could work but they might perform as normal correctors.
Do girders really help in FCCee with so few magnets?
Tolerance of global deformation of the ring?
IP tuning knobs are needed to control IP optics.
CEPC results (see link on the slides) show good DA after correction. Maybe thanks to the better control of IP parameters or lower misalignment tolerances, or 2 IPs vs 4 IPs.
Let's contact CEPC expert, Y. Wang to present.
Oide suggests to put larger weight in IR region. Tessa might try.
Alignment system expected to be defined by the end of the year. What about FRAS?
Smoothing seemed not possible for FCC-ee due to the size-> Automated system?
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Esmaeil, Impact of quadrupole magnet axis shift in H
0.2mm systematic shift in quads makes optics unstable. Max. displacement without sextupoles is 0.15mm. Orbit correction works to reduce orbit to ~0.2mm in H and less in V (up to 60% sextupole strength) with MADX. Simulations with ELEGANT yielded different tunes (maybe because of tapering) and not good orbit correction. Next steps would be beta-beating, tune-shift after orbit correction, different energies, etc.
Oide-san highlighted that the sextupoles should not induce vertical orbit.
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Cristobal, Impact of b2 errors in dipoles
A b2=4 units seems too much as it generates above 2% beta-beating. A tolerance about 1.6 units would be more desiderable. The study restricting to the 5FODO cells is to be performed.
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Elaf, pyAT-based loco and orbit correction implementation and first test
pyAT-based loco tools have been demonstrated to work in PETRA III lattices. First evaluations using FCC-ee latices have been presented. Next step is to evaluate LOCO in FCC-ee, first without synchrotron radiation.
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