Summary notes of the LCU meeting on 10/08/2010

Present: HB, RDM, OD, SF, MG, BH, YL, IP, MS, RT, SW, CB

Report from meetings

• General information -> MG
  Concerning safety, biocell training will become compulsory for LHC tunnel access.
  Forms will have to be filled for any job related accidents including nearly missed accidents at work or for work related trips including the daily trips from home to CERN and back.
• LMC -> MG
  The LHC continued to make excellent progress. It reached peak luminosities just over 1.e31 cm^-2s^-1 last week. The 50 bunch fill patter was improved to avoid extra collisions and weak bunches. At the end of the technical stop this weak, the LHC will be re-commissioned for the fast 10 A/s ramp and bunch trains using 150 ns and with now also external crossing angles in IP2/8. Further details and presentations with reports on single event upset in electronics and the forthcoming heavy ion run can be found in the LMC minutes.

• LBS -> HB
  The LBS#17 meeting was held on the 23 Aug. Alick MacPherson presented an update on data exchange between machine and experiments and YL first results on simulations of the fast losses which could be compatible with dust particles in the LHC.
  A planned contribution on machine induced background trips by ALICE was postponed by them to the next meeting.

SLHCv3: selected topics -> RdM (slides)

RdM gave a first presentation on the LHC upgrade plans studies.
Here he focused on the optics part related to reaching smaller beta*.
A second presentation on other aspects including beam-beam is planned for the next time. The studies follow on what was previously called sLHC and is now referred to as HL-LHC.
In the previous round of studies, the peak luminosity increase from a reduction in beta* to 30 cm in the upgrade phase 1 was rather modest (37%). Here he presented more recent ideas (developed by SF) to lower beta* 30 cm in the crossing angle plane and much further, down to 7.5 cm in the orthogonal transverse plane. The limitation from chromatic aberration at low beta* and strength limits in Q4-Q5 are avoided in the new scheme by using the neighboring insertions around IP1 and IP5 for the squeeze to values lower than beta* = 60 cm. At top energy, there is enough aperture in the arcs to allow for increasing the beta functions and to profit from larger amplitudes at sextuples for the chromatic corrections.
The preferred technology for new magnets will be Nb3Sn to allow for shorter magnets and less parasitic collisions, however Nb-Ti would still be acceptable for the upgrade.

AOB

None

Last update: 2-Septeber-2010

MG & HB

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