Summary notes of the LCU meeting on 09/03/2010

Present: CA, HB, MS, MG, BH, JJ, YL, JN, MS, YS, RT, RM

Report from meetings

• General information -> MG
  There has been good progress in LHC commissioning, even if the availability of the LHC for beams was only 45%.
  A golden orbit with an rms of only 0.4 mm was established, well below the specified tolerance.
  The beta-beating was corrected in most insertions. The overall beta-beating is now down to close to 20%-30%.
  Last Friday, the experimental magnets were brought on and their influence on the LHC machine corrected without any problems. Concerning the spectrometer magnets in IR2 and 8 new settings have been generated based on measured field maps (thanks to Per Hagen). Sample jobs have been stored in the official afs repository.
  The separation bumps required for luminosity scans were successfully tested.
  One of the next things to do are aperture checks. The search for the "hump" in the tune spectrum continuous.
  A one day stop is required to test changes for the nQPS system and perform cryogenic maintenance (de-icing of filters). Hardware modifications will be validated and then a two-day technical stop will be organised next week. All this is required before the ramp to 3.5 TeV can start.
  A preliminary report from the IR upgrade task force is schedule for tomorrow's LMC.

The IR2 optics for 3.5 TeV  -> JJ (slides)

JJ reported about work on the IR2 squeeze for 3.5 TeV (the proposed sequence was computed by TR). As reported in previous meetings, there is no need for a pre-squeeze separate from the at 3.5 TeV (this would save time). It is very difficult to obtain a smooth transition between the highly constraint injection optics and the squeezed physics optics.
He showed the beat-beating, tune, n1-aperture and chromatic changes during the squeeze. After several iterations, few point were added at the beginning of the squeeze and this made it possible to decrease the beta-beating between squeeze points to the 1% level.
There are still points below 3 m beta* for which the beta-beating is higher than 1%: this should be fixed as well as it is relevant for the ions run this year.

AOB

None

Last update: 09-March-10

MG & HB

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