----------------------------------------------------------- Minutes of the ABP-RLC team meeting of 09.09.2005 present: WH, AG, TP, FR, DS, Rama Callaga (BNL) and people attending his talk web site: http://ab-abp-rlc.web.cern.ch/ab-abp-rlc/ ------------------------------------------------------------ (1) Minutes of last meeting, pending actions, announcements ----------------------------------------------------------- The list of actions is posted at http://ab-abp-rlc.web.cern.ch/ab-abp-rlc/Actions/actions.htm . The discussion on the minutes of the RLC meeting of 26.08.2005 was delayed to a future meeting. (2) Superconducting RF cavities for High Current Energy Recovery Linacs ----------------------------------------------------------------------- Rama Callaga gave an interesting talk on current developments and challenges of ampere class SC RF cavities for high energy electron cooling to combat intra-beam scattering in view of a future RHIC luminosity upgrade. The SRF gun will be ready by end of 2006 and the 20 MeV prototype Energy Recovery Linac will be operational in 2007 for early tests. The challenges include multi-cell cavity design to control HOM's, multibunch instabilities due to high Q transverse modes, and quench performance. (3) Progress with the LHC Beam-Beam tracking campaign ----------------------------------------------------- WH reported progress and preliminary results of the bb tracking campaign being carried out in collaboration with DK and E. McIntosh on the BOINC system (LHC@home) and the CPSS screen savers using a new run environment for SIXTRACK. There were some initial problems with the BOINC system, related to AFS disk space. The foreseen study includes tune scans for nominal versus PACMAN bunches exploring two crossing scenarios, i.e. alternating HV crossing planes and HH crossing planes. 80 tunes will be considered using 60 seeds for the MQX field errors, 4 amplitude ranges, and 17 angles. Globally this means about 10^6 cases times 10^6 turns to determine dynamic aperture. The present status of the tracking campaign is that, using 20 seeds for the triplet errors, the HV cases have been completed while the HH cases will be completed in about 1.5 months: the best working points are not very seed-sensitive. WH said that DK will come at CERN at the end of October and added that Lausanne University can provide support to parallelize multi-particle simulation codes to study coherent beam-beam effects. (4) Highlights from Snowmass ---------------------------- DS reported about ILC discussions and organization. A list of 40 questions was prepared where decisions have to be taken rather soon. A baseline design should be ready by the end of 2005. A technical question particular relevant for the CERN site study is whether the beams should follow the Earth curvature or not: this implies a difference in depth of about 35 m over 30 km and has implications for the He cooling plant. Other technical aspects include a modification of the RF cavity shape to reduce the peak magnetic field at the cavity surface, limited by sparking. This should increase the accelerating gradient by 25%. DS will collect information about the main linac lattice useful for future simulations by PE and AL of feedback, tuning, and dispersion bumps for ILC vs CLIC following the Earth curvature. Posted on the web: Slides by Rama Callaga and WH Web site: http://ab-abp-rlc.web.cern.ch/ab-abp-rlc/