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Accelerator Update for June 20, 2008 - June 23, 2008 |
Friday June 20 The day shift began with Tevatron (TeV) in a dry squeeze, with Operations monitoring the Recycler (RR) stash (376.4E10), with the Antiproton Source stacking (56.4E10), with the Main Injector, Booster, and Linac operating normally, with the Collider Detector at Fermilab (CDF) and DZero (D0) waiting for beam, and with the SciBooNE / MiniBooNE (BNB) experiments taking beam. At 8:26 AM, a Klystron RF station (KRF3) tripped off. It reset. At 8:53 AM, a Pbar Debuncher vacuum pump (D:IP712) tripped off and would not reset. An expert investigated and said the problem was in the tunnel. Operations put the TeV into shot setup at 9:28 AM. Operations prepared the Pelletron for access at 10:49 AM. Operations established store 6238 at 11:07 AM with an initial luminosity of 269.13E30. The Pelletron came out of access at 11:42 AM. An RF expert began a Pbar Debuncher cooling study at 1:04 PM. The study lasted about 40 minutes. There was no stacking during the study. At 3:21 PM, Operations reported that the supply and return pressure for the TeV sector B1 LCW system had started climbing around 1:15 PM. Operations contacted experts who reported that the pressure was building up in the heat exchanger. They took the B1 house out of service and began repairs. A MI expert began a study period at 3:31 PM. Operations reported at 3:59 PM that the Recycler had stashed antiprotons three times during the day shift. Operations established beam to the Meson MTest experiment (T971) at 4:45 PM. The experiment had been taking beam parasitically. Experiment T979 began taking beam parasitically. At 5 PM, BRF17 & 18 tripped off on a vacuum indication, but there was no vacuum problem. The trip coincided with a lightning strike. The stations reset. Operations disabled beam to MTest around 6 PM. At 7:13 PM, a Pbar Debuncher septum (D:ISEPV) tripped off on a ground fault. It reset. At 11:27 PM, Operations reported that bad beam positions were causing numerous beam permit trips in BNB. Operations tried to tune with no success. They lowered the BNB beam intensity. Operations reported at midnight that the Recycler had stashed five times during the evening shift. Saturday June 21 The midnight shift began with Operations monitoring store 6238 (76.04E30) and the stash (336.3E10), with Pbar stacking (76.04E10), and with BNB taking beam. Operations terminated store 6238 at 12:29 AM. Operations established store 6239 at 2:39 AM with an initial luminosity of 273.7E30. At 2:51 AM, a Booster corrector magnet (B:HL14) power supply’s output went to zero. Operators investigated, but could find no obvious problem. Operations called in an expert. A power supply expert reported at 3:43 AM that B:HL14 had a bad amplifier and he replaced it. Booster resumed sending beam at 3:54 AM. Operations established beam to MTest at 6:41 AM. At 7:50 AM, KRF5 tripped off for the first of two times in six minutes. It reset. Operations reported at 8 AM that the Recycler had stashed four times during the midnight shift. At 8:26 AM, a TeV vacuum pump (T:DIP8) tripped off. It will be reset in between stores. At 8:31 AM, KRF5 tripped off. It reset. Operations reported at 9:57 AM that the TeV sector B1 heat exchanger cleaning had begun. At 10:33 AM, KRF5 tripped off. It reset. A water expert reported at 12:31 PM that the TeV sector B1 heat exchanger work was done and he was pressurizing it. At 3:10 PM, the Pbar AP-0 sweeping magnet power supply tripped off and would not reset. The PBKICK front end (FE) was also down; operators rebooted it. Operations contacted an expert who suspected that incorrect settings had been loaded into the power supply by PBKICK. Operators adjusted some timing delays and the power supply reset. At 3:37 PM, BRF8 tripped off. It reset. Operations disabled the MTest beam at 6:04 PM. Operations terminated store 6239 at 6:23 PM. Operations put the TeV into shot setup at 6:37 PM. At 7:12 PM, a MI kicker (I:KPS5S) tripped off for the first of two times in one minute. It reset. Operations reported at 7:59 PM that the Recycler had stashed eight times during the last 12 hours. Operations established store 6240 at 8:32 PM with an initial luminosity 280.8E30. At 8:50 PM, Operations reported a rise in temperature for the I- Source. Operations contacted experts. At 11:07 PM, KRF5 sparked and tripped off. It reset. Sunday June 22 The midnight shift began with Operations monitoring store 6240 and the stash, with Pbar stacking, and with BNB taking beam. Preaccelerator experts came in at 1:04 AM to check out the problems with the I- Source. At 1:20 AM, MI vacuum pumps (IP825, 826, and 827) tripped off. They all reset. At 2:27 AM, a Booster vacuum pump (B:IP31) was found off. It was reset, but the vacuum didn’t seem to get better. Two minutes later the pump tripped off again. Operators investigated, reconnected some control cables and the pump resumed working. At 5:34 AM, Operations reported a vacuum burst in the Pbar AP-2 line. Operators reset the vacuum pump but the line didn’t pump down. The pumps that tripped off first were IP720 and IP725. Operators contacted experts. Operations transferred the antiprotons in the Accumulator to the Recycler at 6:42 AM. Operations began preparing Pbar for access at 6:48 AM. At 7:52 AM, BRF5 tripped off. It reset. Operations reported at 8:01 AM that the Recycler had stashed eight times during the last 12 hours. Vacuum experts reported at 8:11 AM that they had hooked up extra vacuum pumps to the AP-2 line and were checking for a leak. At 8:22 AM, LRF2 tripped off. It reset. Vacuum experts reported at 9:19 AM that they had found a vacuum leak on an AP-2 719 scrapper (collimator). An O-ring had gone bad. At 9:42 AM, the Booster East Anode Power Supply tripped off with no indication of why it had tripped. It reset. At 10:39 AM, BRF3 tripped off. It reset. At 10:49 AM, a Linac quadrupole power supply (L:QPS101) tripped off. It reset. At 12:55 PM, KRF6 tripped off. It reset. Vacuum experts reported at 1:06 PM that he would try to repair the leak with Vac Seal. At 2:05 PM, the Duty Electrician reported that the air conditioner at TeV sector D4 was having a bearing failure. He installed a portable AC unit. Vacuum experts reported at 2:08 PM that the Vac Seal repair failed. They were going to spoil the vacuum and try to reseat the flange and O-ring. At 6:02 PM, BRF8 tripped off. It reset. At 6:30 PM, vacuum experts reported that two attempts had been made to reseat the flange and both failed. They will next try to reform a new O-ring.
This picture shows the location of the leak in the Pbar tunnels. Operations reported at 8 PM that the Recycler had not stashed during the last 12 hours. Operations reported at 8:20 PM that mechanical and vacuum experts reported that the collimator would have to be replaced. There is a spare, but they were not sure if it was leak tight. Since the collimator was mostly used for studies, they will replace the collimator with a beam pipe. At 9:29 PM, a Booster vacuum pump (IP61) tripped off. It reset. Vacuum experts reported at 11:23 PM that they had the Pbar spool piece in place and they were beginning the vacuum pump down. Monday June 23 The midnight shift began with Operations monitoring store 6240 and the stash, with Pbar stacking, and with BNB taking beam. Operators reported at 12:18 AM that they completed a search and secure of the Pbar AP-2 enclosure. Operations resumed sending beam to BNB at 12:21 AM. Operations terminated store 6240 at 1:02 AM and then put the TeV into shot setup. Operations established store 6241 at 3:05 AM with an initial luminosity of 220.80E30. At 4:37 AM, BRF9 tripped off. It reset. At 4:44 AM, Operations reported that BRF10 didn’t have a gap. Operations turned off BRF9 & 10 and brought BRF19 on in their place. Operations established beam to MTest at 5:11 AM. An operator investigating the BRF9 & 10 problems reported that BRF9 power supply had gone bad and he replaced it. Operations turned off BRF19 and brought BRF9 & 10 back on line at 6:16 AM. A MI expert reported at 7:11 AM that water experts were beginning to clean the MI-50 heat exchanger. A Recycler expert began a drag rate measurement study at 7:31 AM. Operations reported at 7:58 AM that the Recycler had not stashed during the last 12 hours. Pbar resumed stacking at 8:04 AM. The Plans for Monday The plans for today are to stack, stash, and store. |
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