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Accelerator Update - July 30-August 1
Wednesday July 30 Pbar stopped stacking due to a controller problem at 8:20 AM. Operators contacted an expert and then prepared the tunnel for access. The expert replaced a power supply for a Programmable Logic Controller at 9:22 AM. ComEd admitted that they had suffered two power glitches this morning at 3:18 AM and 5:19 AM. This accounts for the two Booster power supply trips (WAPS) this morning. An expert began making changes to the Main Injector (MI) flying wires at 8:48 AM. He was finished with this by 3:18 PM. MI expert began a study period at 8:55 AM. A Linac RF station's (LRF2) water skid tripped of at 9:32 AM. Operators got the skid back on and a Linac expert had the station operating normally ten minutes later. While the Linac and Pbar work was occurring, another Pbar expert repaired a Pbar Debuncher (DRF1) at 9:41 AM. Linac beam resumed at 9:44 AM. MI and MiniBooNE beam resumed at 9:52 AM. Stacking resumed at 10:23 AM. Earlier, a Booster RF station (BRF11) was brought back online. It tripped off twice at 10:47 AM and then at 10:49 AM and once again at 11:47 AM. A Pbar Debuncher power supply (D:H301) tripped off at 11:26 AM. An expert replaced the supply and had it back in operation 35 minutes later. At 1:30 PM, Operations received a fire alarm for the Tevatron (TeV) sector F0 service building. At the same time a F0 RF power supply caused a trip that aborted store 2830. RF expert investigated but could find nothing wrong. The thought was that maybe a two-way radio had caused the abort, but tests with the Fire Department didn't prove that out. Operations put the TeV through a dry squeeze at 2:35 PM. TeV experts then began a study period at 3:07 PM. At 9:06 PM, the TeV suffered a quench. A vacuum controls problem, which closed vacuum valves, may have been the cause of the quench. Operations contacted TeV and Vacuum experts at 10:11 PM. Earlier, the Collider Detector Facility (CDF) and D-zero (D0) accessed their collision halls. CDF came out of access at 11:53 PM.
Thursday July 31 D0 came out of access 12:02 AM. Vacuum experts replace two controller cards at 12:31 AM. Operations put the TeV through a dry squeeze at 2:05 AM. Two Booster RF stations (BRF5 & 6) tripped off due to a vacuum burst. Everything reset okay. A TeV study period ran from 3:30 AM to 5:51 AM and then went into shot setup. At 8:10 AM, cryo technicians confirmed a valve problem with the wet engine at the sector A4 service building. They had the valve adjustment completed by 8:31 AM. The TeV suffered a sector A1 quench at 8:57 AM. This occurred while ramping up for the next store. The store was lost. Investigators found no reason for this trip. Pbar resumed stacking at 9:19 AM. Linac suffered a temperature problem with its transition buncher cavity LCW. This turned off MiniBooNE for about twenty minutes. A MI vacuum burst occurred at the NuMI stub at 5:54 PM. This halted stacking until 6:15 PM. At 7:07 PM, the TeV suffered a sector F1 quench. A console in the Main Control Room froze at the beginning of a load proton aggregate. A lightening and rainstorm rushed across the lab around 10 PM, which caused a few trips, alarms, and havoc for the operators, but nothing major happened.
Friday August 1 Operations put the TeV into shot setup and at 3:52 AM established store 2847 with an initial luminosity of 3.5E31. Pbar resumed stacking. CDF had a problem at 3:57 AM with equipment that lets them know when it's okay to start taking data. This problem was resolved by 5:46 AM. At 5:32 AM, Booster beam problems required Operations to lessen the MiniBooNE beam intensity. This was still the case at 8 AM.
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