Minutes of the May 9, 2008 Tevatron Dept Meeting http://indico.fnal.gov/conferenceDisplay.py?confId=1804 * News (Ron) - The CDF and D0 spokespersons will show their appreciation for our crossing 4 fb^-1 delivered to the experiments this evening at the Users' Center. Congratulations! * Weekly Operations Summary (C-Y Tan) - The Tevatron delivered 46.8 pb^-1 to the experiments over the past week. There have been 9 stores with initial luminosities between 192 and 285 (our 3rd highest) ub^-1/sec. Only 1 was lost unintentionally - store 6115 aborted after 7 hrs when an offsite power glitch tripped off multiple RF stations. Shot 6122 was lost during the low-beta squeeze when there was a quench in the A-side B0Q3 magnet (again) and a sloppy abort that quenched multiple locations around the ring. The good news is that we finally think we understand the origin of this rash of quenches late in the squeeze - over the past few weeks, our orbit smooths and adjustments through B0 resulted in invalid current requests from the VA47 dipole corrector ramp card in one squeeze slot, so the corrector was not outputting the intended current. We will work with controls to develop methods to catch and prevent this problem and perhaps even improve the ramp cards' firmware to eliminate the troublesome "feature" that we need to avoid. Vacuum tests support no leak in the warm beam tube @ B0. Additional B0 scans show the same aperture as two weeks ago. Other problems include: VA43 BPM is dead in the tunnel; C0 pond pump failed - currently using a fire hose to provide cooling water to the C0 cryo compressors; occasional fake B0 BLM aborts during proton injection; pbar emittance blow-up at start of HEP reduced by lowering pbar tunes. * Tune Measurements with BBQ (Chip Edstrom) - As part of his master's thesis project (Tan is advising), Chip has been using the BBQ (baseband tune) to measure proton tunes during HEP store. A two-stage fit must be done to 1) find threshold for eliminating spikes from the spectra, then 2) refit without the data points above threshold. The BBQ tunes are available as datelogged ACNET parameters (T:BBQPHQ, T:BBQPVQ). There is fairly good agreement with measurements from the 1.7 GHz Schottky system. There is evidence that BBQ can see coupling that the 1.7 GHz system cannot. Future plans include additional control parameters, gating for bunch-by-bunch tune measurements, try measuring pbar tunes. * RF Changes during Pbar Cogging (Fedor Emanov) - Fedor noticed the proton RFSUM oscillating with an amplitude of ~100 kV during pbar cogging. He sees similar oscillations in the proton bunch length as measured by SBD and his fast oscilloscope connected to the resistive wall monitor. Apparently there can also be some proton bunch length growth before/after cogging. Fedor will continue studying the process with John Reid's help. If possible, this bunch length growth should be eliminated. * Plan for Next Week (All) - Deliver luminosity. - Develop plan to fix the B0 orbit more robustly and prevent a future occurence of the VA47 problem scenario - Chromaticity tracker (Tan, proton-only) - AC Dipole (Ryoichi, proton-only) - Measure low-beta lattice (Alex, proton-only)