Minutes of the March 20, 2009 Tevatron Dept Meeting http://indico.fnal.gov/conferenceDisplay.py?confId=2466 * News (Ron) - The Main Injector and Recycler Depts will be merged; Ioanis will head the combined dept and Paul Derwent will move to HQ to lead the accelerator upgrades for NOvA. Anyone interested in attending the USPAS in June (Albuquerque) should let me know soon. * Weekly Operations Summary (Dean Still) - The Tevatron delivered ~58 pb^-1 to CDF and D0 over the past 7 days. After recovering from the glitch in the D0 service buidling (mouse-induced flashover in breaker panel?), there have 8 stores with initial luminosities between 271 and 314 ub^-1/s. All stores have been terminated intentionally. No shots were lost before reaching HEP. We have not been quenching D0 late in the squeeze, although no single cause has been identified. The 11th proton bunch in each train has been blowing up occasionally at flattop/early in the squeeze - could be a tune/coupling issue - needs more investigation. The HEP tune mults were calibrated. A turbo pump in A3 was replaced. TRF2 tripped off during store 6907. The automated proton injection closure tune-up was made operational. Other completed studies described below. * Crystal Collimator at Start of Store (Dean Still) - The (horz) crystal collimator was used in place of the tungsten target for collimating protons at the start of store 6903. Scraping took longer than usual, partly out of caution, and it can be made faster in the future. There was no obvious sign of channeling, but the angle was set to where channeling had been observed previously. Proton halo at the experiments was only slightly higher than normal, but well within limits. The angle drifted by ~90 urad over the store; that remains a mystery, but likely some thermal effect. Overall, it was a successful demonstation of use during HEP stores. * Space Charge Compensation Attempt with TEL-2 (Aleksandr Romanov) - The goal was to create a "column" of electrons within the TEL-2 solenoid and see if it could compensate space-charge tune shift of protons at 150 GeV. Heaters in TEL-2 were used to degrade the beam tube vacuum so that the protons would ionize the residual gas to generate the electrons; built-in electrodes can be used to trap the electrons. When the electrodes were turned on, vacuum rose 2 orders of magnitude quickly and there was significant proton loss. It is thought that an electron avalanche occurred and then caused an electron cloud instability. There was a vertical tune shift of ~0.006. The trapping electrodes used were probably too far outside of the solenoid and allowed the electrons to hit the walls instead of finding their way to the TEL-2 collector. There are other electrodes available. * Plan for Next Week (All) - Deliver luminosity. - Bumper magnet as abort gap cleaner (Bruce et al., proton-only 150 GeV) - Crystal Collimator (Dean et al., start of HEP) - Chromaticity Tracker (Tan, proton-only) - Lattice Measurements (Alex, proton-only) - TEL-2 e-column (Alex and Alex, proton-only)