Summary notes of the LCU meeting on 14/06/2011

Present: HB, RC, RdM, SF, MF, MG, BH, TM, MS, RT, FZ, TaR, ZY

Report from meetings

• SLM and general information -> MG
  Administrative rules will change and make it essentially impossible to bridge the gap between a CERN thesis contract and the following contract as UPAS.
  There are discussions between the staff association and the CERN member states on the CERN pension found.
  There are delays in the office renovation plans around building 6 and 9. As circulated by email, an ABP Group Meeting and BBQ will take place on the 28 June.
  FZ introduced Tatiana Rijoff as new Technical Student in our group to work on beam-beam compensation for the LHC.
• LHC -> BH
  The LHC is running very well with good fraction of time in physics. For further information see the latest news. 

• LMC -> FZ
  The last LMC had presentations on some of the potential issues in the LHC with Tobias Baer on UFOs (unidentified falling objects) and Olivier Brunner on RF arc trips. For further info see the LMC minutes.

Update on beam macro-particle interaction for LHC -> ZY (slides)
Zhao Yang gave an update of the work he is doing with FZ on the kinematics of the interaction of dust particles with the beam to improve the understanding of UFOs observed in the LHC. He varied the input parameters of his equations of motion to see if he can reproduce the observations in the LHC and understand the parameter dependence.
He finds that magnetic fields have a minor effect. In particular, he tried to simulate also multiple passages of objects through the beam as observed in some cases. The model is based on round objects. A not well understood point appears to be the modeling of how the macro-particles charge up.
The electron cloud effect is at present not included in this context and the interaction between the falling object and the electrons might provide new phenomena.
SF suggests to also look at quadrupole effects.

The modeling should be further reviewed and improved.

AOB

None

Last update: 16-June-2011

MG & HB

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