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LMC preparation meeting
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6/R-018 (CERN)
Andy, beta* et al
uncertainties to quadrupoles are included in the beta* calculation in segment-by-segment.
Running twiss many times for the response matrix computation might slow sbs a lot. Maybe an analytical calculation could be done to make this really on-line. Backwards and forward propagation are still considered.
2nd iteration on beam 2 to be included.
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Tobias, Chromatic stuff
Observed overcorrections of chromatic coupling in beam2. Modeling the effect of chromaticity for zero chromatic coupling. So a difference of 3 units in X and Y with 0.1 C- gives 30 units of chromatic coupling!
The key ingredient is chromaticity, it should be identical H and V.
Proposed solution: change tune with MQTs after dp/p change. This might affect chromatic beta-beating.
Another solution would be just to scale the measured differences of coupling with the measured natural tunes.
Indeed more elegant would be to measure h1001 in getllm.
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Ana, reanalysis
At injections it is very useful to include global corrections. All offending points disapeared.
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Lukas, IR8 corrections at injection
Various factors:
-When removing BPM15L8 error bars got reduced by a factor 2 from the data during 11th April.
-> One bad BPM spoiled out stuff
-on 9th April still spikes and cleaning would remove many BPMs.
-Still horizontal error bars larger, probably due to smaller excitation
To check the smaller amplitude in horizontal.
Why was BPM15L8 B2 removed? It is clearly bad.
Cuts in GetLLM based on model and error might help in the future.
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Jaime, Piots, New feature in Verena's application
New way to enter AC dipole tune, safer and clearer since there is not need to add up AC dipole DQ by heart. Risk with sent or not sent values -> use clear colors to highlight not sent values.
Assess BPM quality in Verena's application. H & V should be done independently.
Peak-2-peak signals to be displayed someway to avoid kicking too little in H or too much in V
Another improvement: Variable AC dipole flattop. There should be to check that AC dipole is responding
to the change of flattop length.
Full merge of applications might not be so helpful.
Maybe definition of sets in Verena's application should be the way to go! what is a set? to be defined.
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Rogelio, draft of LMC talk
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Ewen, Looking at AC dipole blow-up at 40cm
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