Glen White reported analysis of measured data of tuning by strength of SK1FF in Feb. and June. Smallest beam size was observed with very strong SK1FF setting and it is inconsistent with our model (based on magnet field measurement), suggesting larger multi-pole errors of magnets. We need more reproducibility in IPBSM measurements for confirmation.
T. Okugi reported modeling of multi-knobs and tuning simulations using 4 skew sextupole correctors. He proposed adding 3 more skew sextupole correctors.
He also pointed out importance of post-IP wire scanner for measuring angle divergence at IP.
He also showed effect of BPM electrodes near a quad magnet to magnetic field, measured by Massuzawa.
Discussion:
The measured data of SK1FF tuning is not consistent with the field measurement of magnets. We do not know reason of the inconsistency. If we do not believe the field measurement, present optics (optimized assuming measured multipole fields) should be replaced. Or, the measured data included too large errors. We do not have conclusion.
We decided to add 3 skew sextupole correctors. (in addition to SK1FF):
We have magnets and space (Reference cavity of S-band BPM have to be moved.) Some power supplies will be purchased.
Though we have no conclusion on the model of multipole fields, adding new correctors will not make anything worse. Also using these correctors, we may be able to find locations of the large multipole field errors.
We decided to installed wire scanner. (For measuring beam divergence.)
Schedule of Oct-December Run
Visiting plans of some oversea collaborators were shown.
Planning should be continued offline.
We have to setup ATFWiki for the planning.
Terunuma made IPBSM status report, plan of improvement.
Schedule of Next meeting: July 20, 3 pm Japan time. Agenda will be
Schedule of Oct-December
Summary of modeling of multi-knobs (Report by Glen)
IPBPM plan (Report by Y.Kim)
IPBSM status report (Report by Terunuma)
