Updates on studies

Europe/Zurich
6/2-008 (CERN)

6/2-008

CERN

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Lukas, cleaning, harpy, 4Qs sidebands

Dominik sidebands at 10% level are reviewed and actually they correspond to few BPMS having 50% 4Qs sidebands. To clean these BPMs SVD mode should be reduced to 0.4 svd dominance cut. Maybe svd should be still above 0.7, and avoid longitudinal blow-up, which seems to be key. 

Update presentation with list of 7 bad BPMS -> Lukas

Did isolation Forest clean these guys? Yes.

What to do with SVD, remove modes or remove BPMs? 

Should we rerun SVD after all bad BPMs are cleaned?

Test redoing optics calculations without the bad BPMs to check differences  -> Elena

Scaling versus turn number is ok for harpy.

For peak-2-peak display in multiturn should restrict to 4 non-ATS arcs. -> Mael

Update on different pairs phase advance uncertainty -> Andreas

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Michael, beam tilt 

Formula for angle tilt fully debugged for coupling. 

It explains Georges observations with about factor 2 emittance ratio! -> email to Georges

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Tobias, Report from Tobias

Concerning tune trims at injection they were fully correlated between them, unrelated to energy matching.

Maybe FIDEL? Anyway good news for coupling (Delta is kept constant)

 

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Jacqueline, SKEKB data

SKEKB has discrepancies between dp/p from BPMs or from RF frequency.

What about LHC? -> Jacqueline

Increase tune tolerance in OMC3 to avoid too many BPMs cleaned -> Jacqueline

Rather bad BPM calibrations!

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Leon, k-modulation, precise orbit

Improvement on offset measurement is done via removing data with low signal.

It seems now we can measure crossing angle below 10% -> Leon

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Andreas, PETRA MD

MAF filters were key to have good data!

 

 

 

 

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