Subject: Minutes of TevDept Mtg, Fri Jan 17 From: Vladimir Shiltsev Date: Wed, 22 Jan 2003 19:03:46 -0600 (CST) To: tevatron , annala@fnal.gov, bhanna@fnal.gov, bollinger@fnal.gov, cytan@fnal.gov, erdelyi@fnal.gov, garbincius@fnal.gov, jansson@fnal.gov, jwalton@fnal.gov, kipster@fnal.gov, koch@fnal.gov, martens@fnal.gov, mccormac@fnal.gov, meiqin@fnal.gov, pmivanov@fnal.gov, ranjbar@fnal.gov, rivetta@fnal.gov, ronmoore@fnal.gov, shiltsev@popgtw.fnal.gov, stefanski@fnal.gov, steimel@fnal.gov, still@fnal.gov, tjohnson@fnal.gov, tsen@fnal.gov, val@fnal.gov, volk@fnal.gov, xiaoam@fnal.gov, zhangxl@fnal.gov CC: tevcc , balbekov@fnal.gov, burov@fnal.gov, cheung@fnal.gov, church@fnal.gov, drozhdin@fnal.gov, emclark@fnal.gov, finley@fnal.gov, frankz@fnal.gov, fritzd@fnal.gov, frs@fnal.gov, gromanov@fnal.gov, holmes@fnal.gov, khabibul@fnal.gov, mhuening@fnal.gov, mokhov@fnal.gov, mont@fnal.gov, roger@fnal.gov, scarpine@fnal.gov, slaughte@fnal.gov, spalding@fnal.gov, stephen@fnal.gov, syphers@fnal.gov 1. Jim Steimel summarized Tev BPM meeting held last week: requirements have been reconsidered, there were number of suggestions how to proced with design (e.g., Andreas is in favor of LHC design), Yuri ALexahin was asked to outline reasons why we need turn-by-turn option for all BPMs. Jim still sees modification(fix) of existing BPMs as an option (if not expensive). 2. Jim Volk reported shutdown progress: 50% of C0 has been done, 33% of E17 Schottky project and CDF shielding has been done. Pinger (vert kicker magnet) at E17 was found 1" horizontally OFF the place it is supposed to be. 3. Other shutdown projects: a) Bruce is still waiting for 10 out 16 ion pumps to improve F) vacuum; he observed that A1 and P1 lines significantly deteriorate F0 vacuum is valves are open; b) XL says that TEl gun replacement was successful vacuum-wise, gun test will start as soon as LCW is back; c) Vladimir said that sinking of the B0 lowbeta quads will be monitored by two water levels while shielding blocks are being installed; d) Andreas and Dean will calibrate mechanical movements of some Tev collimators; e) Jim S said that TD guys (Gennady and Temir) will try to measure vibrations of RF cavities and correlate them with Rf phase noise; f) Mike Martens made a point that PSD box removal in the arcs obly will not slow after shutdown recovery, it was decided to remove them. 4. Bruce reported results of Tev aperture scans he and Dan did the last week before shutdown: yes, C0 still was the tightest vert aperture, in all other places apertures were not significantly different from what we measured in Feb'02. Bruce does not see any beam evidence of significant magnet misalignment at B16 - opposite to survey data. 5. Yuri analyzed helix options after C0 magnet replacement and found that it would not be optimal to go back to "old injection helix" with only 2 separators. Instead, he thinks with 3 separators (B11H, B17H,C17V) helix would be better, allowing almost 1 sigma larger beam-beam separation. He continues to work on helices on ramp and during the squeeze where he feels we still need and have possibilities [like - use B11H] to separate beams more. 6. Tanaji analyzed old data on luminosity drop in store #1253 when failure of one of H-separators occured. His model describes all observed phenomena (lumi drop, lifetime, even beam lifetime) very well. He pointed out that one can determine effective emittance from lumi vs (separator voltage) - and result will be beta^* independent. 7. Vladimir have found that effective emittance reported in the Tev store spreadsheet is overestimated because the hourglass factor in the formula is 0.75 instead of 0.6. That has to be corrected by the next Tev coordinator. With that correction effective emittance for store #1953 is equal to 16.5 pi, while eff-emittance from FW measurements is 21pi --> either FW scaling is wrong for p or/and pbars and emittances are actually smaller or beta-function is smaller. The latter does not look probable as estimated beta^* at CDF and D0 is even larger than the design beta^* (42 cm vs 35cm). THe issues should be resolved by - a) FW calibration V/H for p/pbars - that requires better knowledge of beta-functions; b) using lumi(separator voltage); c) ??? 8. Alvin got time to look into losses during record luminosity store #1953 and found that the losses also were unusual - there was high p-loss rate at the beginning of store due to some "beam dynamics" reason. We don't have those large losses anymore (since early November when tunes were slightly corrected). He also observed some saturation effect in E0TOT counter - again early in the store when losses were high. At the end of the store RF bucket losses dominated. ************************************************ FNAL, MS341, PO Box 500, Batavia, IL 60510 Ph +1(630)840-5241 cell. 319-8583 FAX: 840-8737