Minutes of the 06 Sep 2002 Tev Dept Meeting 1) The new A0 abort interlock system (synched to $AA, abort if $AA not present) has been installed, tested, and made operational. 2) Xiaolong presented the store summary report. Since 30 Aug, there have been 7 stores; 5 had initial luminosity > 20 e30 cm^-2 s_1 with 10-12 hour lifetime. The last two, 1728 and 1730 suffered from transverse instability at end of squeeze/beginning of initiate collisions, and luminosity was reduced. (Mike Martens noticed orbits needed to be smoothed; after the meeting, the orbits were smoothed up the ramp and through the squeeze. Decoupled at low beta, too.) 3) Paul Lebrun made a lengthy presentation on luminosity lifetime analysis with SDA data. Paul saw good agreement between measured and expected bunch-by-bunch luminosities (from CDF) for stores 1668-1691 in terms of the actual bunch intensities, emittances, bunch lengths. Stores 1728 and 1730 had poorer agreement, but those are stores which had beam blow-ups at end of squeeze. Some audience members wished Paul had more explicitly removed the intensity losses due to p-pbar collisions. Paul also used 50 mb instead of 75 mb for the p-pbar cross-section; how big of a systematic effect is that on the results? Regardless of those details, there is a large variation among stores in the pbar lifetimes and emittance growth rate. The analysis seems to confirm that vacuum is not the dominant factor in luminosity lifetime. Also, Paul concludes that the transverse and longitudinal growth rates do depend upon bunch brightness. 4) Vic Scarpine presented a status of the BLT system(s). Work is proceeding in parallel on two separate systems: the "old" system using the new fast digitizers, and a scope-based system developed by Dave McGinnis. Both systems gathered some seemingly believable data during a recent shot. Neither system was ready to attempt closure with them, but seeing the data was very encouraging. Comparing the currents features of the 2 systems: fast digitizers scope-based --------------- ----------- protons and pbars pbar only 1024 turns 256 turns return data 10 sec/xfer return data 1 minute/xfer We expect quick progress for both systems. 5) Jim Steimel discussed the status of the transverse dampers. They know the system is timed-in very well. The system has 130 dB of gain. They made progress reducing noise by moving and replacing some cables, but there is still some noise to reduce. Their effort is currently focussed on the digitizer board; noise on the board renders the 14-bit digitizer to have only an effective 10-bit precision. Tan noticed an apparent discrepancy in the phase advance between the kicker and pick-up; the MAD file and measurements disagree by 40 degrees. 6) Valeri Lebedev showed his analysis of the P1 line. (Analysis of A1 line underway.) He was able to model the line well by fudging only two quads. He designed a new lattice the reduce the vertical dispersion mismatch between the line and the Tev. He estimates the current mismatch to cause ~5% emittance dilution. His new lattice, which still has some vertical dispersion mismatch, should have < 1% emittance dilution. 7) Aimin Xiao showed her progress on the A0 lattice modifications. The current A0 lattice still is optimized for fixed-target extraction. A0 has the minimum beam-beam separation on the injection helix. The new lattice addresses this deficiency by making A0 look more like the other long-straight sections E0 and F0. The new lattice increases the minimum separation by 17%, but decreases the maximum separation by 17%. C0 becomes the location with the smallest beam-beam separation on the injection helix. At flattop, the minimum separation is increased 36% over the current lattice. Implementing the new lattice requires warming up F4 and A1 to replace the existing quads. 8) Mike Syphers compared expected and measured luminosities based on the usual measured parameters (intensities, emittances). He showed us how to calculate the hour-glass factor. With the usual bunch lengths, the hour-glass parameter is about 0.5; achieving the Run II specs could gain us ~30% in luminosity from the hour-glass factor alone. Using data from the Tev Coordinator's spreadsheet, he calculated the ratio of measured lumi/expected lumi. That ratio varied over a range of stores (1462-1730?) from 1 to 2.5. Some of the discrepancy may be due to his use of sync light emittances rather than flying wire emittances (sync light pbar emittances known to be underestimated, and some scaling constants had varied over the stores Mike analyzed.) Mike will learn how to extract flying-wire emittances from SDA and hopefully reanalyze the data. Since the meeting was taking so long, Frank Schmidt's presentation on the same topic was deferred to a later date.