Summary notes of the LCU meeting on 13/11/2012

Present: RB, HB, LD, OD, SF, MG, EQ, BS, MS, RT, RT, AL, PH

Report from meetings

• SLM and general information -> MG
  Massimo informed us about discussions about the warm quadrupoles in the collimation regions. They may be among the first to reach the end of life by radiation. Some are used at very low power and could potentially be removed. Thys is looking into this matter.
  IPAC'13 participation was discussed and the list of CERN participants was circulated soon after this meeting. Abstracts submitted to the conference should have at least one co-author who will participate in the conference. Invitations for our end of year party on the 13 December will be send out soon.
  The end of year presentation by Paul Collier on the BE activities this year will be given in January 2013.
• Collimation project status
  Roderik said that the status was recently presented in LMC#156. The main approved changes are to replace the TCTs and TSG.6 by new button pickup collimators, improved TCL layout in IR1 and IR5 and additional passive absorbers in IR3. Hollow e-lenses proposed within the US-LARP collaboration for halo cleaning were reviewed recently at CERN. Roderik will write an executive summary.
• MAD-X status -> LD
  Work is in progress. Andrea Latina document the RF-multipole work. See also the news and updates section on http://mad.web.cern.ch/mad/

Brainstorming discussion of options for post LS1 LHC configuration -> All (slides by MG)

Rogelio will have a presentation on the forthcoming Evian workshop. Evian will be too early to decide on the running configuration after LS1. Still, it will be important to have already a well prepared first view of this subject in Evian.
MG showed slides with questions which we should discuss and try to answer. Both 25ns and 50ns options will be considered.

Points to be considered include:

• Injection: crossing angle (25ns, 50ns), and beta* which may be a bit lower in IP1&5 then at present to simplify and speed up the squeeze.

• A pre-squeeze will be needed for IR2/8 in order to reduce the triplets' strength. This could be extended to ramp and squeeze of the other insertions.

• Top energy : minimum beta* for IP1&5, use of ATS, benefits of flat beams. Roderik is in the process to determine the minimum beta* for after LS1 compatible with aperture and collimation. At present, we can assume a minimum of 35 - 40cm for 50 ns and 45 - 50 cm for 25 ns operation which requires a larger crossing angle.

SF asked for a specification of the maximum chromatic aberration which is compatible with collimation.

MG asked the question about possible interference with high-beta in case we go for ATS.  HB said we already use a separate hypercycle for the high-beta runs which de-couples these runs from the configuration used for high luminosity so that he does not expect any interference. 

AOB

None

Last update: 21-November-2012

MG & HB

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