Summary notes of the LCU meeting on 02/10/2012

Present: HB, RdM, OD, MF, MG, BH, PH, JJ, EQ,BS, MS, RV, FZ

Report from meetings

• SLM and general information -> MG
  Concerning HL-LHC activities, Task 2.3 is progressing with the field quality of the new triplet. Later the new D1, D2 and Q5 magnets will be considered.
  The yearly HL-LHC workshop is planned in Frascati in November, see the workshop page.
  Bernard added that there is good progress on the upgrade optics (Task 2.2). The HLLHCV1.0 optics layout should be released by November.
  The proposed VELO upgrade (reduction in radius from 5.5 mm to 3.4 mm) will be discussed at the next LEB meeting.
  The TEAPOT slicing upgrade discussed in the last meeting is included in the newest MAD-X release and triggered much interest and further follow up. SF confirmed the improvements when applying the new version of TEAPOT to ATS optics.
  Several of us are involved in preparation for MD block 3 scheduled for next week and MD block 4 scheduled for November.
• LHC Status -> BH
  The LHC had a difficult week recovering from the technical stop and various faults and interlocks, see the latest news.
• LMC -> FZ
  Frank reported from the LMC last week, details are in the minutes.
• Collimation
  Massimo said we will now regularly report in the LCU meetings on collimation work.
  Belen said, that there is currently follow up on re-checking of cleaning efficient using loss maps.

Further analysis of the p-Pb run  ->  MS (slides)
Michaela  presented an updated status of the analysis of the recent p-Pb test run, which had 15 p and 15 Pb bunches and provided collisions in all 4 IPs, using the un-squeezed flat top optics. Some losses related to orbit changes were observed when going into collisions. An emittance growth and bunch lengthening was observed for ions. A slow emittance decrease was seen for protons, which is in fact expected from damping by synchrotron radiation. There is qualitative agreement in the main trends with the expectations. More work is required on quantitative comparisons with simulations. No evidence for strong beam-beam effects between proton and Pb beams was observed so far which is encouraging for further studies.

High-beta optics options for ALICE -> PH (slides)

Pascal Hermes gave an update on his studies of possible higher beta options for ALICE. From his earlier studies, it was already known that a beta* = 30 m would be compatible with 50 ns operation but marginal or even incompatible with 25 ns operation. The current studies are based on rather conservative estimates: at least 12 sigma separation for the first parasitic encounters from the IP and 3.75 mum normalized emittance. It requires a full crossing angle of 300 murad, which limits the maximum beta* to 18m for 25ns and to 68m for 50ns operation. He matched optics for beta* = 30m and beta* = 18m. The phase advance at about 220 - 240 m from the IP where roman pots could be installed is about 120 degrees in both transverse planes. His studies will be discussed in the ALICE week scheduled at CERN next week.

Last update: 5-October-2012

MG & HB

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