• Report from meetings
  • SLM -> MG
  • The new mandate for the section and a corrected group structure was presented.
  • A group meeting for presenting the new group structure and the new salary grid will take place at the beginning of February.
  • A request was issued to evaluate the number of offices to be reserved in the Meyrin side in case the ABP Group is moved to Prevessin. Feedback from the LOC members is expected.
  • MEB -> MG
  • The magnet approval is continuing with 5 SSS, 11 SpSSS and around 40 MB to go.
  • A short circuit was discovered  in an MQ and MQTL of a SpSSS (523) and no spare is available. Installation schedule will probably impose to use the non-conform SSS523. There is a shortage also in terms of components.
  • Fidel -> FS
  • Lacking a clear definition of what FIDEL is offering. FS introduced the on-line modeling.
  • FIDEL complicated WISE simple collection of data as it gives the possibility of cmputing the magnetic properties at an arbitrary energy, based on the magnet model. A meeting should be made to check WISE data. Also, TR will continue the discussion concerning polarity convention in the LHC MADX sequence.
  • Joint Machine-Experiments Workshops -> HB (pdf file)
  • The workshop was organized over two days. There were a number of questions from the experiments' side regarding beam dynamics issues.
  • Among the talks Roger Bailey presented a preliminary 2008 run schedule. There are still discussions regarding the engineering run of 2007, in particular following the hardware problem of the heat exchanger of the MQX quadrupoles.
  • The second day was dedicated to luminosity monitoring. Experiments seem interested also on how the machine can measure luminosity. The calibration is very important and it may be provided by TOTEM, but it is impossible at the early stage of LHC.
  • HB suggests to have a PhD student proposal with subject the luminosity monitoring and complement this with background studies.
• Status report of FP420 -> FeRo (pdf file)
• The FP420 consists of a forward proton tagging detector, 420m from the IP, looking at out-going protons  with less than 1% loss of their momentum.
• The budget is mainly covered by UK institutes, and a large collaboration was established.
• R&D phase was initiated and a design report should be available on spring 2007.
• The main mechanical impact of the detector in the machine is that the cryogenic line should be extended.
• Some ongoing investigations on impedance effects are presented. Both simulations and measurements will be performed to estimate the impedance of the device.
• A study of the machine induced background as seen by the FP420 detector were presented. The interpretation of the results as well as the initial distribution will be discussed with the Collimation Team.
• Chromatic behavior of V6.5 LHC optics -> TR (pdf file)
• This study was triggered by the fact that Igor Baichev using his LHC model could not reproduce tune vs dp/p shown in the LHC design report. In particular, crossing between the tune curves for collision optics are observed.
• In view of the new optics under study (V6.501) some update of the chromatic behavior is needed. Work on this topic was done by A. Verdier (LHC PN 103 concerning V5.0) as well as SF (LHC PR 308 concerning V6.0).
• The study is done using Riccardo's procedure with many families of sextupoles, which enables the flattening of the tune curve vs dp/p
• RA questions why the curves are not completely flat and TR replies that the criterion is to keep the same dependence in horizontal and vertical Q so as the tunes do not cross. YP asks  what are the parameters minimized? TR answers that the sextupole families minimize Q' and Q''. YP adds that it may be interesting to minimize off-momentum beta-beating.
• TR concludes that moving away from the phase advance of V.6.4 relies on operational feasibility of chromaticity correction with more than 2 sextupole families.
• RdM asks what is the problem for changing the phase advance of the arc, instead of the straights. YP reminds that with respect to hardware there is no limitation (individual powering of arcs), but sorting is done based on fixed phase advances and may not be so efficient if they are changed.
• RA asks when the version becomes official? MG and TR answer that the only outstanding issue is the chromaticity problem and that prior to the official release, the optics will be communicated to the Collimation Team for qualification studies.
  
• AOB

Colour code:

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

Last update: 08-Feb-07
MG & YP

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