The BDS meeting (via vidyo) - 26 May
6/R-012 - conference room
CERN
Jochem, 2-beam tuning simulations
Improvements even with 4 iterations of the improved algorithm (3500 iterations). Continuing.
Some knobs are not efficient in the iterations, they could be removed.
2nd order knobs also tested with some benefits. To develop further.
Edu asks about Guina Pig parameters ? This has not been tried. Edu finds that
this has a big impact in simulations.
Andrea asks about number of luminosity measurements. The factor 2 comes from the 2 different beam lines.
Next-> Ryan will do more 2-beam iterations
Fabien, Energy scan study proposal
Simulations for various optics, clear distinct behaviours.
Hardware to be fixed in June, hopefully.
Marcin, ATF2
Shintake monitor not working, lasers are unstable. To be fixed.
GM, Douglas, good progress in yesterday successful shift.
Edu, FFS Tuning Analysis with Local scheme
Issues with initial parameters, lattice and Guinea Pig. Rogelio comments and ideas on how to well organize are very welcome.
Daniel comments that even the right profile from the linac should be used.
Clearly 2nd order knobs are require to remove aberrations. 1st order aberrations in Horizontal are flaky.
T122, T126 and T346 are the 2 dominant 2nd order aberrations (T324).
Jochem -> Maybe doing this for horizontal aberrations might be useful. -> For Santander.
Marcin-> Paper by Okugi san with precise relation between correlations and sextupole type.
2nd order knobs built.
100% machines reach 80% luminosity in 2000 iterations (improvement by order of magnitude).
GP iteration is changing the GuineaPig parameters.
90% of the machine reach 92% of the lumi.
3 keys: GP, 2nd order, redefinition of linear knobs (latter probably an artifact of this particular simulation).
-> latest news in Santander
Marcin -> in simulations ATF2 xy coupling correlation knob important and required.
Edu -> xy knob to be introduced in the FFS (they exist in the instrumentation section)
Jochem -> how is the range of the knobs changed?
Edu -> Just redefining them with different range.