• Report from meetings
  • SLM -> MG
  • A US-LARP BEAM-BEAM 07 workshop will be organized by W. Fischer et al. FZ and OB contribute to the programme committee.
  • The new salary grid has been approved. The main differences are the new steps have been halved and the salary bands have been extended. All other mechanisms are the same. Transitions between salary bands will be probably more difficult with the present scheme.
• Beam behaviour at VELO during powering failures of the warm dipoles and quadrupoles -> A. Gomez Alonso (pdf file)
• Two questions have been raised regarding the engineering run with collisions at 450 GeV: What is the  maximum bump amplitude and the minimum VELO closure.
• Both questions were considered and possible solutions found. However, some issues for the machine protection were raised (YP), triggering studies on failure scenarios around the VELO. 
• Simulations include fast failure scenarios of warm magnets of the collimation IRs. Other magnets, such as bump compensators, are supposed to be covered by the machine protection system.
• Distributions of 5000 particles are simulated in the position of the VELO over time during the failure.
  • For MBXW failure, the losses appear in collimators;
  • For MQW failures the losses are still somewhere else in the lattice.
• The worse failure scenario is when the voltage in the power converter of the spectrometer compensators reaches its maximum value. Other failures consider an exponential decay, corresponding to a power supply switched off.
• Hypothetical losses in the VELO, when a closed orbit is considered: Still losses are taking place in the collimators
• SF suggests to study a combination of quadrupole failure and closed orbit error which may be a worse case scenario for qualifying the losses. A failure of a single quadrupole  (Q4 or Q5) may give also quite 
• YP suggests to do failure studies for the compensators as they are bipolar (need of FMCM)
• WH suggests to remove the crossing angle from the simulations, as it would be the case during the engineering run.
• In conclusion, the VELO becomes an aperture limitation only if it is closed with injection optics, but most of the losses are covered by the collimators
• Collimators are considered as black absorbers and the simulations do not include any scattered particles. A code modification has to be implemented in order to record all losses in case of changing magnetic field
• Simulation of a real dynamic magnet change in MADX is  elaborated by HB and AK
  
• Presentation of the new Group structure -> MG
• The RLC section is split in one section for CLIC and CTF3 under Hans Braun and the rest of the staff are moved to LOC section which becomes the LHC Commissioning and Upgrade section. Elias Metral contributes in this section but his main activity are LHC injectors (SPS supervisor).
• YP moves to LHC Injectors section as he is a PS supervisor and works on PS2 and JBJ moves to the CLIC section.
• AOB

Colour code:

• Black: proposed agenda
• Red: outcome of discussion at the meeting

Last update: 08-Feb-07
MG & YP

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