minutes ABP-LCE meeting 21.02.03 present: EB, WH, JJ, AK, EM, BM, GP, DS, FR, FZ ------------------------------------------------------- Agenda: urgent matters and ongoing activities --------------------------------------------- ACTION FR -> "Create LCE web page with updated action items" new; end of February PENDING, STILL TIME. ACTION FZ FR -> "Estimate order of magnitude of problem for the LHC" study ongoing, in connection with next item TALK TO A. FERRARI - next week (FZ DS) concerning FLUKA and EGS simulations. ACTION FZ -> "Review SNS studies on local e- cloud at collimators" done; estimate of electrons due to collimation from Pivi/Furman -> this step still to be understood (by us) to get estimate for LHC We RECEIVED INFORMATIONS AND PAPERS from J. Wei & M. Furman; next step same as for previous item. ACTION FZ -> "Check transverse wakefield with proposed tapering angle" DONE; EB is now implementing these wakes in the HEADTAIL CODe to study the possible incoherent emittance growth over 1e6 turns WE WILL CONTACT W. BRUNS TO COMPUTE THE WAKE WITH GDFIDL. ACTION FR LV -> "Review boundary conditions for non-continuous coating, e.g. stripes of carbon. Review allowable distance between collimator slices, in case collimator jaws are realized in discrete slices: sawtooth surface." PENDING, SECOND ORDER EFFECT ACTION FR -> "include considerations on Landau Octupoles and report to LHC Collimation Project meeting on Friday 21" DONE, EXCELLENT PRESENTATION ACTION LV -> "Review and document specs for Ti coating of TDI absorber (a few microns), and check consistency with proposed specs for collimator coatings." done; new estimate of res.-wall wakes reported by LV documentation of results still pending UPDATED ESTIMATE, ONE REPORT JUST PUBLISHED, ANOTHER UNDERWAY POSSIBLY HELP BY E. METRAL ACTION FZ DS -> "actively run/debug code to get results before Chamonix" INTENSE ACTIVITY, STILL DEBUGGING THE CODE cos theta dependence was removed from elastically reflected yield ACTION FZ DS -> "stricter handling of ECLOUD code; fix date to freeze the code, include input file and example; introduce version numbers, and documented changes; tracing of old versions; use cvs; time scale 2 weeks" done; new ecloud code web page: http://www.cern.ch/proj-ecloud-code suggestion to add list of changes in different versions and short explanation of new features in future versions DONE ACTION AK -> "2 bunch calculation, with improved SPS impedance model, also including space charge, res.wall, by end of February" Res. wall wake was included. it has no effect as expected for 1 or 2 bunches. 1 detailed bunch, other bunches are rigid. It was suggested to compute a full LHC bunch train in the SPS. ACTION FS and WH -> "inform LHC optics team of different MAD-X results on different lxplus machines" DONE; but several new problems encountered due to change of operating system; FS and E. McIntosh are following this up Beam-Beam: preparation for Chamonix ACTION JJ -> "Report on tracking with imperfections and beam-beam in the coming weeks" ACTION FR -> "Manpower allocation and time schedule to be discussed with LOC and group leader". DONE; FR informed group leader, LOC prepared optics files and offered assistance to submit tracking jobs. FR asked BM to help with high priority ACTION BM -> progress report BM LOOKING INTO THIS problem. MAD program provided by Oliver DOES NOT YET RUN (confirmed by JJ). Lost files partially recovered with help of SF. Triplet correction is still missing. (SIXTRACK tracking) JJ develops his own file, different approach (MAD tracking) ACTION FR -> "get access to lxplus classes for WH, DS, FZ" DONE, under collective and impedance (8+8 Gbytes, thanks to FR and HB) JJ mentioned 1 Gbyte are also needed for optics web pages. JJ visited Japan last week, for ICFA meeting and Asian LC symposium. He also saw KEKB, ATF and new FFAG ring. JJ will report 5-10 minutes in next ABP forum. FR presented his slides for the collimation meeting. Feedback has factor 3-5 safety margin according to Trevor Linnecar. Higher-order combined multi/single-bunch head-tail modes as computed by Scott Berg require strict control of chromaticity. WH reports that RP gave a succesful talk at DESY, very well received. She interviewed with many people and is still there.