Presents: RWA, CB, HB, SF, MG, JJ, JBJ, AK, RdM, GRdM, SR, FS, TW

• Follow-up of actions from previous meetings
  • Correction of aperture database (Action: MG).
    • Even though the aperture database is not completely up-to-date and fully cross-checked, S. Chemli said that the part concerning the octant 8 should be almost correct. It is then decided to make an attempt of extracting the data from the database, generating the aperture model and comparing it with the one developed by SR (Action: JJ).
  • Verification of the aperture in IR8 (Action: WH, JBJ).
    • The action is still in progress. A value of the crossing angle for beta*=1 m has to be defined so that the available aperture is conform to specification for both polarities of the spectrometre's compensation magnets. This issue is crucial for the acceptance of the triplet quadrupoles of IP8, which is on-going at MEB.
  • Additional check of the electrical drawings for point 8 (Action: MG).
    • The five drawings for IP8 were checked by JBJ, FS and MG. Few errors were found and they were communicated to P. Proudlock.
    • It was found that the MQTLs in Q11 are reported to be rotated by 180 degrees with respect to the vertical axis in the layout database (hence with connections downstream of the beam direction), while this feature was not reported in the electrical drawings. Following a number of checks with the experts (H. Prin, S. Russenschuck et al.) it was found that: the layout database, which was reporting the rotation, is indeed correct (this is crucial as the new version of the error routines is based on the information extracted from the layout database). However, as far as the polarity is concerned, inside the assembly the appropriate modifications are made so that from the outside the cabling is done as if the MQTLs were not turned.
• Report from meetings
  • MEB -> SF
    • Approval of SSS is in progress: sectors under considerations are 4-5 and 7-8.
    • Approval of MB is in progress: sectors 7-8 and 8-1 are completely allocated; sector 4-5 features about 30 missing MBs; sector 3-4 features about 120 missing MBs.
  • FQWG -> SF
    • The difference in magnetic behaviour of main dipoles according to the type of inner cable (i.e. type 01E or 01B) is almost negligible. The largest difference is found for the hysteresis of b1, for which 3 units were found. Therefore, it is decided to allow for mixing a limited number of cryodipoles with different inner cable in the same sector.
    • The results of the measurements of the field direction in SSS gave a value of 0.8 mrad (rms): the limit is 0.5 mrad (rms). The situation is considered to be conform.
  • LTC -> MG
    • A discussion on the organisation of the LHC commissioning took place:
      • Responsibility of the commissioning will be of the EIC.
      • Experienced EICs will need to have experience of operation of collider machines.
      • The newly recruited EICs will not be responsible for the LHC commissioning, but they double the experienced ones and will be in charge of the machine after the commissioning.
    • In a future meeting the planning of installation of LSS8 will be presented. The DFBX will be missing, hence no power tests will be possible for the low-beta triplets. Implications of this fact on the sector test should be made by LOC: feedback is required before the LTC meeting in three weeks.
  • CWG -> RA
    • Analysis of the resistance test (flatness of collimators) completed. Software upgraded to take into account any deformation of the jaw surface (e.g., fit of measured shape, parabolic deformation, ...) of the collimators' jaws.
    • A collaboration with the Kurchatov Institute was launched for the modeling of the shock waves in collimators.
    • As an outcome of the Controls Group Review it was proposed that the collimators' controls will be staged.
    • A meeting organised by the Machine Protection Working Group on the quench limits of superconducting magnets will be held on Friday September 30th.
    • Thomas Weiler joined the Collimation Team as a fellow starting from September 1st. MG will add TW to the invitation list of LOC meetings.
  • SLM -> MG
    • A proposal is made to organise Group seminars to exchange information between the sections, and improve the team spirit within the Group. Such seminars should be held monthly. A list has been prepared with contributions expected from LOC members.
    • A list of people responsible for the commissioning of BDI systems was circulated by R. Jones. He asked to have also names of people from ABP who could support the commissioning. Such a list was already presented by OB at the LOC meeting of 15/03/05. MG will fill in the list provided by R, Jones taking into account the available information and he will circulate the table for feedback from LOC members.
• Summary of the second MAD-X day -> FS
  • Successful event: it has been proposed to have a MAD-X day every year.
  • Open points:
    • Tracking: the five-dimensional tracking is problematic.
    • Matching: the matching with PTC is still missing.
    • Makethin: the issue of slicing solenoids was raised.
    • Matching with variable length between magnetic elements: still not available.
  • A work plan will be prepared and presented in a forthcoming meeting.
• Feasibility of Adjusting Dispersion at the Injection Point in IR2 -> AK (pdf file)
  • The analysis made aimed at showing whether it is possible to generate dispersion bumps at LHC injection to improve the optical matching. The amplitude of the dispersion bump is about 10 cm.
  • Using those orbit correctors in IR2 that are not part of the crossing bump or separation schemes it is found the required dispersion bumps cannot be generated.
  • SF proposes to use MQTs to generate dispersion waves, closed within the insertion, as tuning knobs.
• AOB
  • HB reports that Lionel Neukermans (LN) has joined the LOC team to work on the halo and tail generation for linear colliders in the framework of EuroTeV. MG will add LN to the invitation list of LOC meetings.
  • SPS scrapers: compatibility between LHC and high intensity beams -> HB (pdf file)
    • Following a joint analysis made with G. Arduini, it turned out that the collimators' settings to be used in the SPS both for the LHC beams and the high-intensity proton beams for CNGS, are not compatible with each other. A document will be prepared and a solution proposed.