Minutes of the Aug 23, 2002 Tev Dept Meeting 1) Congratulations to Bruce Hanna and Roger Tokarek with 25th anniversary of the employtment with FNAL! 2) Frank Schmidt of CERN is visiting us for 6 weeks will work on beam dynamics and general operational issues in the TEV. 3) XLZhang reviewed this weeks' luminosity which was not great because of large pbar emittance at injection and low-beta. He also mentioned large pbar losses early in the store associated with longitudinal shaving (significant bunch length reduction) in the first few hours in recent stores, 4) Paul Lebrun analyzed pbar emittance growth between injection and low-beta: uncorrected emittance becomes some 20% larger (and much smaller for protons). But Paul sees that FW pbar signals are saturated and if proper correction is done than the blow-up is actually more significant (>40-50%, sometimes 2 fold). This saturation issue to be resolved soon by Stephen and Paul. 5) Ron reported upgrade of his TevArrayViewer (see on console 6 in MCR). Can now display 1, 2, or 4 separate variables simultaneously. 6) Vic Scarpine gave an overview of the BLT issues how they see it now: reflections created by proton bunches in 100 m long cables attacted to one end the BLT stripline plates intefere with weaker pbar signal. Solution: to install some 20 dB attenuator in the tunnel (before the cable). When: ASAP. Seems that (later today) Jim S and Tan agreed that it will not disturb operation of the bunch-by-bunch longitudinal damper exploiting the same stripline. 7) Jim S and CYTan got very encouraging results with the notch filter added to their transverse damper system; measured and found that real values are all positive - as needed for stability. The last part needed for the closed loop opeartion to be finished today and we all are waiting for the first results with "real" damping (next week). 7) Mike Martens said that orbit smoothing last week was done pretty quickly (some 1 hours for 2 planes on the ramp - compare with 1-2 shifts in the past). He will work with Patty McBride of CD to make the algorithm even faster and less prone to flaky BPMs. 8) Tanaji and Co made horz beam-beam separation larger at the end of one of recent stores and did not observe any significant lumi-lifetime improvement. [note that vert separation has been made larger several stores ago but it's still early to say something about benefits] 9) They also scanned tune working points (WP) (by some 0.01 in both planes around nominal WP, including crossing diagonal twice) in order to find a better one (with smaller losses) but were not successful. While crossing diagonal Q_x=Q_y pbar x-y beam size interchange was observed (Frank). (Note from Tanaji) Several tunes were found with slightly smaller losses (about 10-20%). This included the mirror symmetric tune (interchange of horizontal and vertical tunes). The losses were not significantly smaller (by 50% or more) at any of the tunes scanned. The emittance exchange was observed only for the anti-protons when crossing the difference resonance. 10) Vladimir summarized TEL studies: p-lifetime at 980 GeV varies by factor of about 100 at different WPs. There are large areas with very small losses. 11. Alvin continues to analyze losses. Vacuum + lumi + (properly scaled) losses out of RF describe perfectly loss of IBEAm later in recent stores, but p-losses early in stores are high. Why? - may be due to beam-beam with weak pbars... Once again he asked for vacuum calibration p-only store. Pbar only is also of interest. Next "end of store" he will recalibrate RF leak losses.