Minutes of the 29 April 2011 Tevatron Dept Meeting https://indico.fnal.gov/conferenceDisplay.py?confId=4412 * Weekly Operations Summary (Dean Still) - The Tevatron delivered 57 pb^-1 to the experiments over the past 7 days. There have been 8 HEP stores with initial luminosities between 237 and a new record 405 ub^-1/s. (NB - right after the meeting another new peak lumi record was established = 416 ub^-1/s.) All stores were terminated intentionally. The B1 and E1 cryo wet engines required maintenance. The D0 IP was adjusted to closer to nominal. The Tune Tracker required rephasing after maintenace on the 21 MHz Schottky electronics. There was a no-beam quench when attempting to run the sequencer script to ramp down low-beta quads for collision hall access while leaving the Tevatron @ 980 GeV; it was part operator error, part bug. * Crystal Collimator Study (Dean Still) - The T-980 team made an attempt to image channeled beam using the recently installed pixel detectors. The pixel detector (only 1 of 3 per plane is operational) is working in that they can see profile of some beam, but it isn't clear if it is channeled beam. For this study, the channeled beam may have been below the set pixel location. * Lumi-Leveling via Bunch Length (Ron Moore) - In a brief end-of-store test, the RF voltage was reduced 30% to increase the bunch lengths. The observed lumi drop = 8.5% in good agreement with ~8% expected from the changes in hourglass factor and beam loss. As the RF voltage was lowered, there was beam loss (mostly protons) likely due to longitudinal tails leaving the bucket and creating DC beam since the bunches were quite long at the end of this extended store. It was noted that the reported intensities from SBD varied noticeably more than the FBI versus RF voltage and/or DC beam. The next step is to repeat this test in the middle of an HEP store when the bunch lengths are a bit shorter. * Plan for Next Week - Deliver luminosity, see how we integrate with init lumi >400 ub^-1/s - Separator scan (mid-store) - Crystal Collimator (T-980, 3 hr EOS) - Hollow e-beam (Giulio et al., 1 hr proton-only, 3 hr parastic/end-of-HEP) - Lumi-Leveling (Ron, mid-store - lower RF voltage, gradually ramp over few hrs while CDF & D0 take data)