Subject: Minutes of the Tev Dept Mtg, Dec.20 Date: Fri, 20 Dec 2002 15:31:38 -0600 (CST) From: Vladimir Shiltsev To: tevatron , annala@fnal.gov, bhanna@fnal.gov, bollinger@fnal.gov, cytan@fnal.gov, erdelyi@fnal.gov, garbincius@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, holmes@fnal.gov, jansson@fnal.gov, mokhov@fnal.gov, mont@fnal.gov, scarpine@fnal.gov, slaughte@fnal.gov, spalding@fnal.gov, stephen@fnal.gov, syphers@fnal.gov 1. once again: no call (from MCR) zones are Tue 12/24 noon to Thur 12/26 8am and Tue 12/21 6pm to Wed 1/1 noon 2. Vladimir informed that several of us (Mike M, Jerry, VS, Valery, Peter) and some BPhys guys are going to write reports on Run II upgrade to be presented the AAC meetying Feb.4, 2003. 3. Jim Volk gave a brief overview of the Jan'03 shutdown work. All projects are on good track so far. Newly approved item - install 60 tones of steel to shield CDF (in the CDF hall). Another 40 tones of the CDF shielding may be installed in summer'03. 4. Tan reviewed recent stores: there was a bunch of decent stores (L=27-33 E30) before studies this week, bunchlength blowup has been seen in the #2078 at flat top, but Kim Steimel found that that was just because soem electron card was not reset properly. It's fixed (?) and no blowup was seen in the latest store #2090 [we lost that store at the very beginning of ythe HEP because of safety system failure]. Store #2087 - just after studies - had bad p-lifetime at 150. Possible reason is that chrimaticvities on p-helix are much (5-7) units higher than on central orbit, thus should be lower significantly (down to 2-4-? units) for better lifetiem. Vertical damper was OFF in that store, horizontal was ON. 5. Ray Stefansky on survey work during 1 shift access: a) C0 survey complete; b) B-sector survey complete and huge 10 mm elevation difference found between dipoles B16-1 and B16-2 (one is up 5 mm, another down 5mm); Jerry thinks that may affect(reduce) aperture there; c) survey of sector E is not complete and survey group would lik ethat to be done before shutdown. 6. Tan present recent chromaticity measurements on ramp: it was found that on p-helix C_H starts at about 10 at 150, goes upto 24-26 at 153 and then goes down to 16 at 980, C_v jumps from 10 to 22 at 150-153, then down to 11 and slowly up to 20-26 at 980. THese large values of chromaticities are though to be excessive, and potentially hampering ramp efficiency (Vladimir thinks that for current proton intensities we need some 10-12 at 150 going up to 14-18 at 980). On pbar helix hor chriomaticity fluctates between 9 and 18, hor between 10 and 22 - those are definetely too large and can/should be reduced significantly (under 10?). Over the next 2 weeks Tan will reduce C_v,h step by step at different steps until problems appear. Two previous chromaticity measurements were made on central orbit by Dean+VS and Mike Martens gave somewhat contradictory results but also pointed taht C_v,h is probably too high on ramp. 7. Mike M outlined nice work done by him and Jerry at 150 p and pbar helices to decouple Tevatron (coupling difference between two helices is now <0.002) and set tunes (differential tunes <0.001 all over C.O. and both helices). For precise coupling measurements Mike tracked one of synchtro-betatron lines all the time in H-spectrum and one in V-spectrum. [Would be nice to have an automatic tune tracker] 8. Alexei Burov informed of recent shift in the Tev impedance analysis: a) they do not think anymore that separator plates significantly contribute into total transvesre impedance; b) instead they blame lambetrston magnets. His first analytical estimates show that some important factors were missed in previously used formulas and now C0 and F0 lamberston magnets can give up to 5 MOhm/m (note - we estimated Tev total Z_transvesre as 3-5 MOhm/m from instability thresholds). All that shold result in serious "STRONG head-tail instability" (which should exsist even at zero chromaticity). THis week experiments in part confirmed the conclusion b) - they observed that increment of the instability varies by factor 2 or so when high intensity coalesced beam is moved closer to inner surface of the C0 lambertson or further from it (chrtomaticity wa kept constant). THus, Alexei, Peter and Valeri are in strong favor of C0 lambertson replacement and also suggest to shield F0 labertson inner surface by conducting foil. 9. XL and Frank did base tune scan at the end of store and found that losses can be reduvced if tunes are moved toward diagonal: Q_h down by -0.002 and Q_v up by +0.003(4). 10. Vladimir analysed vertical pbar scrapind dat aat the end of store: a) (initail, before scraping) vert emittance found from intensity decay is 20-24 pi - under assumption of 1-dimensional scraping; b) FW seems to have a very good dynamic diapason (43 to 2 pi) but reports initial larger emittance of 43 pi; c) SL reports emittances with significant offsets due to (abberrations?) - some 12-18 pi. Jerry pointed out that c) might be due to local coupling. Analysis to continue, need to scrape protons next time. 11. Markus Huening has improved directivity of p-bar Schottky detector byadditional 10-15 dB. For the first time pbar (Schottky) tunes at injection were demonstrated. Next step - to make the instrument a) on-line; b) available in MCR; c) compare results with BLT tunes. 12. Merry Christmas!