Summary notes of the LCU meeting on 01/12/2009

Present:  GB, HB, RC, OD, MF, BH, JJ, EL, YL, AM, AR, FS, MS, YS, RT, GV, SW, FZ, JC

Report from meetings

• SLM and general information -> MG (slides)
  Prof. Javier Cardona from the university of Bogota was welcomed to our group. He is currently here for a couple of weeks. Plans are that he would return with collaborators for more extended periods.
  MG reminds that people who want to keep access right to the tunnel have to follow safety training, which can be done on the web in case of electrical safety awareness. Another mandatory course is on the biocell, for which one should enroll via EDH.
  MG reminds that we are invited to the BE department meeting on the 11 December and our Christmas party on the 17 of December at 16:30.
  After the OK from the department head, IPAC abstracts should be submitted to the conference before the 9 of December.
  The LHC had an excellent start this year. The progress has been very impressive. First collisions at injection energy were already achieved on Monday last week using single bunches of pilot intensities.
  MG showed slides of the tune excursions measured in the first energy ramp in the LHC. After correction of tunes by feed forward, both beams later reached 1.18 GeV.
  The solenoids of the experiments were brought up yesterday. As expected, the ALICE solenoid produced a small orbit distortion and a nearly negligible tune coupling. The effect of ATLAS on orbits and tunes is small. For CMS, an effect in the coupling of about 0.005 in c- was observed as expected. Using the coupling knobs prepared by us, it was possible to compensate the solenoid effects and to decouple the beams down to the level reached previously without solenoids of about 0.0018 in c- for both beams.
  There has been good progress in the collimator commissioning with beams. Plans for the next days are to further commission the protection systems and beam dump system, aiming for collisions at 450 GeV at an intensity of some 1.e10 and up to 4 bunches per beam towards the end of the week.
• FZ -> LMC
  FZ reported from the last LMC meetings. Details can be found in the minutes.

Action and Phase Jump Analysis: From RHIC to the LHC -> Javier Cardona (slides)

JC described an action and phase jump analysis of BPM data. It allows to determine and localize machine errors (linear and non-linear) by looking at discontinuities in the action and phase variables.
The method was successfully applied at RHIC and it was also applied to SPS data taken with strong sextupoles excited.
There are plans to establish a collaboration to apply this method to LHC BPM data. In this respect JC will take part in the forthcoming measurement sessions during the LHC beam commissioning.

Optics in IR2 for 3.5 TeV -> JJ (slides)

As reported previously, the IR2 optics is highly constraint at 450 GeV due to injection and aperture requirements. For the 3.5 TeV operation next year, ALICE requests a beta* = 3 m which should be reached directly in a squeeze without pre-squeeze to save time. A satisfactory solution for the squeeze was found with a single point between 10 m and 9.5 m beta*.
MG suggested to try to further reduce the beta beating by inserting another intermediate point and to add the evaluation of the tune and chromaticity variation during the squeeze. Matching the separation bumps will still have to be done.

Workshop on Tevatron after end of physics -> FS (slides)

There will be a workshop at Fermilab in January 2010 to discuss the possible use of the TEVATRON before the shutdown in 2012 for machine experiments (further information can be found here).
FS is in the organizing committee and is supposed to collect the CERN requests for measurements. Stefano Redaelli and RWA will participate in the workshop. Possible subjects to study in the TEVATRON are collimation, beam-beam compensation and electron cloud. Further ideas are welcome and should be sent to FS.

AOB

None

Last update: 01-December-09

MG & HB

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