Minutes of the 20 Sep 02 Tevatron Dept Meeting 1. Vladimir outlined Tev plan for FY03: it consists of >20 projects, of different priorities (1 to 3, depending on potential impact on luminosity). Each project has person in charge, potential impact on L, needs, uncertainties, required resources and plans of actions are indentified. The plan is subject to correction by BD management. 2. Bruce informed about the first look into the near future Tev Vacuum improvement plan discussed with ANL people. The goal is to improve Tev vacuum by factor of two after Jan'03 shutdown that should lead to better lifetime at 150 and smaller losses at low-beta. The plan includes a) gas concentration and content (A,Z) studies in cold/warm regions; b) modification of C0 vacuum chamber and warming F4 and A1 houses during January shutdown; c) test and certification of any new devices to be installed in the Tev. Replacement of ion pumps is under consideration. 3. D.Johnson summarized last week's luminosity: we started with L=25.7 store last Fri but in following days it L degraded to 20's, then to 19 and even to 14 because of the MI coalescing problems, until finally it was fixed last night by J.Reid and we were back to 24 in #1770. The last store was in part hit by TEL (it was not properly turned OFF for pbar injection) which shaved some 75% of bunch #3 in 7 pbar transfers. XL also mentioned that the latest store had very low effective beam emittance at IP (16.4 pi mm mrad). 4. Jim Crisp and Tom Meyer shared their plan to fix recently observed FBI irregularities (some 10-20% in ANG/AWG observed in pbar only store; Alvin reported 4% WG/DC difference in proton only store). Plan: a) recalibrate FBI channels; b) study the background subtraction effects. 5. Tanaji observed no L-lifteime improvement after 8% increase of hor separation in the middle of store #1669. Possible explanation: it was low intensity low-L store, beam-beam effects were not a big issue. Needs to redo the test again in the next "normal" store. 6. Sasha Drozhdin presented recent background calculation with taking into account large angle scattering on the residual gas. His conclusion is that these single scattering particles dominate in the detector backround if the vacuum pressure exceeds 2e-10 Torr (vs actual warm N2 equivalent (1-2)e-9 in Tev). The proposed solution is to install H and V collimators in front of three final dipole before the IRs. If set at 13 sigma, these collimators will reduce the backround by factor of 10. (editor's note: The possible effect from secondary particles not yet modelled.) Ron is supposed to understand does CDF really want that to be done in Jan shutdown and - if "yes" - start the project. Bruce will provide the RGA scans from warm and cold regions - those to be taken into account for more realistic modeling.