Summary notes of the LCU meeting on 3/11/2009

Present:  MA, OB, HB, MF, MG, WH, WH, BH, DK, El, YL, AR, YS, RT, GV

Report from meetings

• General information -> MG
  Two doctoral students started beginning of this month, Miriam Fitterer on the LHeC supervised by HB and Lutz Hein working in the HSL section on LINAC 4 and transfer lines supervised by BH.
  Dobrin Kaltchev is with us at CERN this month working on commissioning.
  For the yearly report ABP is expected to contribute 10 pages with 2 pages from every section. MG will be happy for input and prepare and circulate a draft.
  The recent LHC sector 2-3, 7-8 test was successful. The test started on the evening of Friday 23 October with the first injection of lead ions into a sector of the LHC.
  MG said there will be soon new revisions of the LHC as-designed and AS-uilt sequences including all collimators installed in the 2009/2010 run.

Sector test: polarity measurements -> RT (slides)

RT showed data and analysis results from the recent sector test.
Particular attention was paid to few magnets where polarities were in doubt from first checks last year. Most of the ambiguities were resolved.
It is to be stressed that skew circuits seem to be in complete disagreement with all known conversion rules for the polarity between MAD-X and the machine.
Doubts still exist for Q4R2 in terms of potential aperture swap. This will be checked with priority in the next sector test planned for the forthcoming week-end.

Beta-beating and latest news for new optics for IR8 -> EL (slides)

EL continued to work on the squeeze in IR8 without pre-squeeze as relevant for the planned 3.5 TeV run.
Compared to the results shown last time he found a smoother transition in terms of corrector strengths and determined the beta-beating (maximum in all the machine), tune changes and aperture. The aperture with crossing angle and good spectrometer polarity was found to be fully sufficient for n1 = 10.5 sigma for the intermediate collimator settings down to the requested beta* of 3 m (the limit would be reached close to 2 m). He finds that squeezing in 0.5 m beta* results in sufficiently small beta beating and tune changes, except for the last point between 4m and 3m where an additional point may be required. To be further followed up.
After the meeting EL computed the relevant optical quantities for the solution with new matched optics. In addition he verified that the beta-beating outside IR8 is negligible for both Beam 1 and Beam 2. After having added the crossing scheme this solution will be copied to the optics database.

Recent news for optics studies for IR2 -> JJ

JJ continued to work on the squeeze for IR2 without pre-squeeze. The squeeze starts from the rather constrainted beta* = 10 m injection optics. As for IR8, the aim is to be able to squeeze down smoothly to beta* = 3 m with sufficient aperture for separation and crossing angle. To be further followed up.

AOB

None

Last update: 3-November-09

MG & HB

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