Minutes of the Jan 28, 2005 Tevatron Dept Meeting 1) Tan gave the store summary for the week. Reliability was a problem; only 3 of 5 stores made it to HEP, and only 1 was terminated intentionally. Cryo problems plagued us again this week. The D1 wet engine failed soon after collisions were initiated for store 3934; D1 quenched soon afterwards. The E2 wet engine failed and caused a quench at E2 4.5 hours into store 3943 (initial lumi = 61.3 E30 cm^-2 s^-1. (TRF5 also tripped during that store.) Both engines suffered from grease contamination and required overhauls. Store 3939 was lost between steps 15 and 16 of the squeeze by a quench of B0Q2. It turns out there is a sudden, sharp loss of pbars there when beam separation reaches a minimum during the transition from the injection to the collision helix. Store 3945 (initial lumi = 99.5 E30 cm^-2 s^-1) ended after 33 hrs when QFA4 tripped off on a quench indication. No problem was identified, but additional diagnostics were implemented to catch the failure should it reoccur. Store 3948 (inital lumi = 96.3 E30 cm^-2 s^-1) ran smoothly was terminated intentionally after 28 hours. Tan also noted that the proton bunched beam lifetime was significantly lower (60-80 hrs) for this week's stores as compared to the several previous stores (110-130 hrs), although the lumi lifetime was not too different. All separator load resistors were flushed during the downtime caused by wet engine overhauls. 2) Tan and Jerry provided more information about the pbar losses between steps 15 and 16 of the squeeze. There is definitely a dependence on the transverse emittance of the pbars. The smaller pbars from the recycler suffer very little or no loss, while the bigger pbars from the accumulator suffer more. One also sees a dependence in the position within a train, so beam-beam effects also contribute. The loss that quenched B0Q2 in store 3939 may have been exacerbated by the highest proton intensity to date (~9700 E9) at flattop. The vertical orbits had been getting ratty, and smoothing the orbits seems to have helped reduce the loss. However, we should limit the proton intensities until we understand the problem better. Perhaps we can raise separator voltages a bit during the transition in order to increase the minimum beam separation. 3) Jim Volk summarized the status of HLS (hydrostatic level sensor) systems in the Tev. The Budker HLS in the B0 straight is functional. There has been a gradual increase in the average level over the system's length, but Jim doubts it is real; it is likely an effect from the electronics or evaporation of the water in the system. He will continue to investigate. One can see the ~12 hr oscillation from the tidal effect. The HLS also detects motion from quenches that is similar to what is seen on Todd's tiltmeters - a sudden change, followed by a 3-4 hr "relaxation" to the original level. It was suggested that the changes are caused by thermal effects; gases rushing out the Kautzky valve cause the iron to ice up and distort, the slowly return to normal shape as the ice melts. The Budker and PPD HLS in B-sector and the PPD system in E-sector are just being commissioned, but the E-sector system did see an effect from the E2 quench that ended store 3943. Jim also gave a brief summary on the accelerator alignment workshop he attended. Many labs were represented, and they discussed interesting topics such incorporating GPS into site networks, trying to achieve the ever-tightening tolerances, and the use of feedback from HLS systems for automatic leveling during operations. 4) Andreas and Mike shared their thoughts and impressions from a CERN LHC workshop they recently attended. They both felt CERN will need a lot of luck and help to shave 6 months off the installation schedule. One item they found disturbing was the decision to test only 1/8 of the cryo ring in the tunnel before installing magnets in front of it. Any post-installation repair of the cryo line will require moving magnets and incur 1 month downtime. CERN is definitely paying attention to issues we've experienced in the Tev, particularly component damage as a result of objects that can move into the beam, e.g., collimators, vacuum valves, forward pot detectors. LHC needs a robust abort system to prevent damage from all that beam; even at injection energy = 450 GeV, the total beam energy will be 2.4 MJ. 5) Andreas summarized status of the IPM project. There have been some manufacturing difficulties, but he hopes to have the *tunnel* items ready for installation by the last week of February. Installation would require a 3 day shutdown that included setup and breakdown time for a bake. Vic mentioned they will try to complete the OTR by the end of Feb, too, so that the OTR can installed the same time as the rest of the IPM. The IPM electronics should be ready by mid-March. 6) Randy summarized the status of sync-light. They now have a simulation that produces the expected images. 80% of the proton light is missing. It's not clear if the incoming light is hitting an aperture, e.g., magnet edge, along the way, or if the light is not entirely falling on the lens. Diffraction effects should contribute 10-20% of the observed beam size. They would like to move in the pbar mirror automatically at the start of each store. A review of the procedures and safety mechanisms will be needed. 7) Stephen reported on the SBD. The SBD does not yet report dp/p, but the goal is to implement that feature by March 1. Stephen is aware of the problems of greater bunch length measurement "scatter" since the shutdown, as well as the intensity measurement increases during the ramp, but those problems will be addressed after the dp/p measurements are operational. 8) Nathan investigated the problems reported with the flying wire system in store 3948. In short, all of the problems ever observed with the flying wires, plus 1 new one, seemed to crop up in that store. An apparent flaky problem with the E11 HV contributed to the missing pbar data during injections. The front-end did not log flies at flattop - somehow the corresponding fly spec got turned off. SDA did not log all the proton injections, because the processing time was abnormally long. On two flies (Before Ramp and After Scraping), the horz pbar profiles are bad just on fly #1 (that's the new problem.) He will continue to monitor and try to fix the problems. Hopefully, they won't all reoccur on a single store like for 3948. Minutes recorded by R. Moore.