Summary notes of Upgrade meeting on 2/05/2007

Present: RA, CB, OB, RDM, UD, SF, MG, WH, MM, VP, FS, RT, TW, FZ

Round table discussion

• FZ:
  • A presentation of the HHH activities for the quarterly report was made. It is reminded to quote support from HHH  in the published papers (it will be added on the LHC-PR-1000 and it could be added also on the report to be published by OB and RdM).
  • The proceedings of the LUMI06 will be published in the current status even though two key papers are missing (one from CMS and one from AT).
  • The proceedings of the ECL2 Workshop will be published soon as AB report.
• OB:
  • The structure that is being set-up at CERN for the upgrade studies relies on Lyn to perform general co-ordination  of the upgrade scenarios (he will also lead the Creation of Network Infrastructure) and Ranko Ostojic to be project leader for the IRs upgrade (Phase 1). He should set-up a working group to ensure the necessary exchange of information between AB and AT.
  • US-LARP Meeting: there is some interest in studying the layouts with slim magnets (D0). This will not be relevant for the Phase 1 studies, however. There is also interest in studying options for cold D1/D2 magnets. In any case the organization of the contributions to the IRs upgrade studies should be made available by mid-May to CERN, prior to submission to the DOE for formal approval.
  • It is agreed that the study of the energy deposition in the triplets will be carried out by N. Mokhov with RdM as linkman. A request for resources will also be issued to the AB department and the topic will also be proposed to AT/MCS, as in that Group some expertise is being built in this domain.
• MM:
  • It is reported that the optics for Beam 1 is ready including the crossing scheme for the layout #1. Beam 2 will be prepared soon.
• SF:
  • The studies for the Phase 2 upgrade aimed at exploring the option of flat beams in conjunction with doublet optics are reported. The main outcome of this study is the definition of a constructive algorithm to generate a prescribed magnetic field by using a distribution of current wires. Even though it does not seem to allow reaching the required strengths, it could be applied for the design of mass-less septa, magnetic collimators etc. A paper is being prepared.
• RT:
  • Beam 1 and 2 optics are ready (thin and thick version) as well as the crossing schemes (provided by WH) for the layout #2. The subsequent studies could start.
  • Correction schemes for the nonlinear field errors of the triplet quadrupoles will be investigated.
  • A link to the directory structure created by RdM was added to the HHH web repository. Once a layout is in final form, a more detailed description will be provided and published on the HHH repository.
• RdM:
  • Beam 1 and 2 optics are ready (thin and thick version)  as well as the crossing schemes (provided by WH) for the layout #3. This optics is the most advanced one and it can be used immediately for beam-beam, DA, and collimation studies.
  • The tracking studies for DA computation should be started soon. A test was made on the impact of multipoles of order higher than 11 on the value of the DA: it seems to be negligible, but a presentation will be made.
  • For the tracking studies, it was decided (following also discussions with E. Todesco) to use only random errors for triplet quadrupoles and to apply the scaling of magnetic field errors vs. aperture as proposed by E. Todesco et al. As far as the rest of the machine is concerned, the errors of the machine-as-built will be used (extraction using the WISE code made by MG). These generic files could be stored in the afs repository for general use.
  • RA suggests to have an aperture model included with each layout: this should be built starting from the aperture model of the machine-as-built and the new triplets' aperture. These files could be stored in the afs repository for general use.
  • The off-momentum beta-beating is between 30%-40% for the three optics at Dp/p of 3×10^-4.
• UD:
  • Simulations for the study of the wire compensation at RHIC are in progress. Experimental tests are also foreseen.
  • Test of the impact of wire compensation for the Phase 1 layouts (#3) are also starting.
• WH:
  • Crossing schemes for layouts #2 and 3 were computed. Analysis of the required strength of the correctors was also performed. Preliminary beam-beam studies were already launched.
• FS:
  • A fix was introduced in SixTrack to allow tracking with multipole errors beyond 11th order. This was applied to a private version in order to avoid disturbance to on-going simulations (beam-beam studies by WH and Dobrin).
• RA:
  • There is concern for the performance of the momentum collimation system due to the huge off-momentum beta-beating. This issue will be considered in more details by the collimation team.
  • In case of modifications to the D1/D2 region, the impact on the tertiary collimators in that area should be assessed.
  • There is concern for the confusion made by the statement that the increased aperture of triplet quadrupoles will remove all limitations of the collimation system. It is stressed that even though this will alleviate the impedance issue, the cleaning efficiency will remain unaffected, the bottleneck being the losses in the dispersion suppressor  downstream of IR7.

AOB

None