Minutes of the Tev Dept Meeting 06/28/02 0. Happy Birthday Jerry! (06/27) :-) 1. John Marriner answered our questions: after July 15 he most probably will work on Recycler, he thinks we are doing well and will get out of the luminosity dip soon; + etc. 2. Vladimir: since 01/01/02 we accumulated 38 pb-1, URA rating (till Oct1) considers 50 pb-1 as marginal, 80 - good, 100-excellent, 140 -outstanding. S.Holmes focuses us to some 4e31 peak lumi at the end of this calendar year and 7pb-1/week. 3: Vladimir informed about visitors coming from other labs. In July that will be Wolfram Fischer (BNL) and Slava Danilov (ORNL), later, probably, Frank Schmidt and Frank Zimmermann of CERN. 4. Major work for October shutdown as outlined by Vladimir: a) C0 Lambertson replacement (ldr - Garbincius, asst- Bruce Hanna) b) Schottky detectors at E17 (Steimel, Bollinger) c) TEL magnet modification (Shiltsev, Zhang) d) vacuum, alignment, cryo, etc. 5. Mike M. summarized dQ/coupling drift + optics meeting: a) feedforward to be used to compensate the drifts; b) experimets: separate Low beta quads persistent currents and the rest of the TEV, cahnge temperature of LHe and see change in dQ drift amplitude. Valery's priorities with Tev optics: a) make injection P1 line "better"; b) order lattice files; c) start lattice improvement studies. 6. There were two stores since last week L=7 and 5.3 e30. Bruce explained reduced lumi by low number of protons and pbar injection difficulties. Emittances, lifetimes are sort of good. SyncLite started to report (some doubt that SL beam size data are correct). Bruce kindly agreed to be the Tev coordinator for one more month (till July 31). 7. Vladimir told that last night high-intensity 36x0 store was 50% success: got 5800e9 protons in narrow gate (=in bunches) at 980 Gev without instability and with good emittances , but it was a bit less than goal (6000) and we quenched early at flat-top. 8. Ron Moore analyzed D0 vacuum pressure rise when pumps were turned off during June shudown and performed similar experiment at CDF. Results indicate taht outgassing rate is factor of 4 smaller than what people though before, thus the average vacuum at CDF and DO is about (5-7)e-9 Torr or 2.5 times better than people though a week ago. [that's the way we improve vacuum - making better estimates]. John M. question why average vacuum does not scale as outgasing rate, Ron referred to M.McKee model (probably, because length of integration is longer than the part of the pipe which outgasses - e.g., if one averages over the whole Tevatron than the CDF outgasing rate would not matter at all). 9. Mikolai Mokhov presented first results of the CDF background simulations due to beam loss. He claims that nuclear inelastic beam-gas interactions all around the ring do not contribute to the CDF background (only few tens of meters around CDF matter). Alvin immidiately pointed to our current understanding that nuclear elestic (or single/multiple Coulomb) interactions are the major source, and the scattered particles are not intercepted at one turn. Nikolai plans to work with us on the source identification and perform vacuum bump experiment. His group will continue tarcking simulations. Starting now he is the Beam Phys contact person on that Tev Run II project. 10. Paul Lebrun analysed store 1443 data and found that proton bunch length growth rate (d sigma/dt) scales linearly with bunch intensity (varied from 60 to 140 e9/bunch). It contradicts previous experiment in Feb'02 and rules out RF noise as a source of the longitudinal emittance growth. THere is no obvious correlation for high intensity store #1369 (160-230 e9/bunch) - ??. 11. Dean found 0.13 mrad F0 lambertson misalignemnt and adjusted Tev orbit respectively. A0 aperture seems to be OK. Yuri and others feel that the Tev aperture now is somewhat smaller than before may 21 or, say, in March. Poor p and pbar lifetime also support that idea, but (Bruce) aperture scan conditions now and then might be different (e.g. wider beam now). It was decided to check apertures in suspected locations and center orbits ASAP. 12. Yuri and Bruce tried to ping the beam and determine coupling from turn-by-turn BPM data. THe fisrt pictures show complexity of the coupling process (synchrotron motion involved). Detail analysis to follow. 13. Mike M. re-measured tunes vs sextupole current on new-new helix. The work has not been finished because of quench. 14. Jim steimel and Tan are commisioning bunch-by-bunch longitudinal damper - they have determined the general sistem delay. Next shift - adjust notch filter. The form of the BTF is strange (2 synch frequencies?) and Vladimir, Tan and - hopefully - someboidy from the BPhys Dept will look into that. 15. There were various discussions why SyncLite is not showing real beam profile, whether new-new helix is responsible for poor lifetime, do losses from abort gaps grow with time in store or go down, etc.