Subject: Minutes of the Tev Dept Mtg. Apr 18 From: Vladimir Shiltsev Date: Tue, 22 Apr 2003 18:52:41 -0500 (CDT) 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, vs , 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 , gollwitzer@fnal.gov, 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, gena@fnal.gov, gromanov@fnal.gov, holmes@fnal.gov, khabibul@fnal.gov, marriner@fnal.gov, mhuening@fnal.gov, mokhov@fnal.gov, mont@fnal.gov, pasquin@Fnal.gov, roger@Fnal.gov, scarpine@fnal.gov, slaughte@fnal.gov, spalding@fnal.gov, stephen@fnal.gov, syoon@fnal.gov, syphers@fnal.gov, vaia@fnal.gov, webber@fnal.gov 1. Dept news: a) Jim Walton and Gennady Romanov(TD) will investigate HV breakdowns in electrostatic separators with electrodes coated by different materials (glass, oxides, etc) - 6 mos; b) Peter Ivanov and BD/Mech Support have started work on F0 lamberston liner (to be installed in summer shutdown); c) there was a quiz on how Tev papers for PAC'03 are doing - most of them at least started. 2. Mike M on the last week luminosity: 6 stores since previous Fri (Apr 11-18), all with luminosity above 3030, the best store #2426 with 36.5. We now have both V and H dampers On at 150 that allows to drop both chromaticities, that helps to save protons (and pbars?), so we run with high proton intensity (around 200e9/bunch at low-beta). SyncLite shows that over recent weeks we run with larger effective emittance (25pi vs 21 pi), mostly due to vertical pbar emittance blowup [over the weekend it was fixed by lowering Q_y by -0.001 at LB] 3. Jim Steimel and Tan were able to restore vert damper for operation by changing local coupling at E0 (T:SQE0, while effect on global coupling was compensated by global circuit SQ). Questions still left unanwswered are: what is driving beam unstable in hor plane? why coupling is not symmetric (Hor damper does not affect vertical stability)? 4. Ralph reported that now two channels of E17 Schottky are "sort of" available to us(ers) - Pbar hor and Pbar vert. They can be timed on particular bunches. Vladimir explored pbar tunes at LB and found that Qv is about 0.59 (-0.001 lower for A1 and A12, Q_h=0.581 (-0.0025 lower for A12, +0.001 higher for A1) - i.e. they are above the diagonal. So, lowering vert pbar tune should help to reduce emm blowup (prooved over weekend). 5. Mike M thinks its time to do global orbit smoothing as distortions are about 2-3 mm ring wide, dozens of dipoel correctors close to their limit (50A) and some are fighting each other. During the short studies he discovered that B0QT3 (trim quad) drifts a lot (now fixed), that TEL correctors can change orbits by 0.5 mm if tripped. He also keeps track of all known orbit corrections and BPM problems/changes. 6. Peter reported successfull attempt to inject beam (280-300e9/bunch) with small(zero) chromaticity with octupoles OZF=+2A, OZD=+5A. Nevertheless, beam loss occured while going from inj bump to open helix - probably because of significant tune changes due to orbit motion. That needs more study time. 7. Yuri did new helix studies and tried to explore ring-wide apertures (to make choice of proper separator settings) but that was only partly successful as over some period of time studiers did not mentioned that one of separators was actually OFF. Besides that there was some discussion on what we want from the helix - Yuri suggests to concentrate on losses on the ramp and 980+squeeze (that has implications on injection helix), while Vladimir and Mike Church think that reduction of losses at 150 GeV is at least equally important. 8. Vahid has been able to measure vertical chromaticity with a pinger and head-tail monitor and same results as by standard dF_rf method. He thinks that in about 2 weeks we might get a tool (program) for quick chromaticity measurements in the MCR. 9. Andreas measured dispersion in all three Flying Wires at 980 and found that they are quite off the lattice model values : 2.2m at E11 instead of 2.03, and 4.76m at E17 instead of 5.28. If that is taken into account then FW hor emittance will change (become larger?). Vladimir tried to take into account all recently measured Fw-relevant parameters (D_x, scaling factors) to calculate emittances and found calculated effective emittance in the right range but changing slower in store than what is really observed.