LHC 2012 - latest news

Week 22: Machine coordinators: Gianluigi Arduini, Mike Lamont

Plan for the week: Luminosity production

 

Date

Summary

Link to report from morning meeting

Monday 4 June

  • 02:18 TCTs in point 2 not executing the fnctions
  • 02:25: Loss of communication with BLM in point 3 Beam dump
  • Investiugations for colimator problem
  • 05:27 Trip of sector 12. RQ6.R1 (QPS)
  • LBDS.B2 problem during pre-cycle. Access reuired for replacing a power supply

08:30 meeting

Sunday 3 June

  •  Fill 2692 dumped by electrical glitch/FMCM at 05:54 having broken a few records (~240 pb-1 in 22.8 hours)
  • Morning - access for QPS
  • Pre-cycle - collimator problem, beam-in...
  • 16:00 another access for QPS
  • 18:00 Not possible to open the vacuum valves after access. Aceess for vacuum. Ion pump power supply replaced
  • 20:46 QPS problem again
  • 23:00 pre-cycle after end of access fro QPS
09:00 meeting

Saturday 2 June

  • 03:39 Trip of ROF.A56B1 (QPS) followed by ROD.A56B1 and RSD2.A56.B1 ==> Beam dump. Endd of fill #2691. ~170 pb-1 in 14 h
  • 7:10 STABLE BEAMS #2692. Initial luminosity ~6.3-6.4x1033 cm-2s-1.
  • Hold beams - SPS interlock problem
09:00 meeting

Friday 1 June

  • 00:00-01:00 Separate beams and attemt to measure chromaticity at the end of the collision process
  • 02:10 Filling
  • 03:09  Beams dumped at 4 TeV by RQTF.A81B2 power converter trip
  • 05:20 second ramp attempt RQTF.A81B2 tripped at ~700GeV
  • 06:30-08:00 Access for power converter replacement (SEU)
  • 08:30-09:30 RF control (phase error) adjustements
  • 11:00 Beam dump when going in collision due to BLMs (end of fill#2690). Tunes
  • 13:41 STABLE BEAMS#2691. Instabilities and losses on some bunches when going in collision due to offset in IP1 and IP5

08:30 meeting

Thursday 31 May

  • 23:58 RF trip. End of fill #2684 - 65 pb-1 in 3.5 h
  • CMS access
  • 02:00-03:10 - Fill 2685. Lost during the squeeze (trip of RCBCH7.L1B2)
  • 06:00 STABLE BEAMS #2686 - 6.4x1033 cm-2s-1
  • 06:05 Trip of ROF/ROD.A56.B2. Beam surviving
  • 16:00 End of fill #2686 - OP dump (150 pb-1 in ~10 hours)
  • 16:30-18:30 Access for QPS in point 1, cryo in point 2, ALICE, BIC in point 5, power converter in point 6.
  • 20:00-21:30 Energy matching
  • 21:30-23:00 LHCb positive polarity check
  • 23:00-24:00 Damper test in collision

08:30 meeting

Wednesday 30 May

  • 04:07 Trip of RQ6.L7B1 (QPS-SEU) during the squueze (2677) - beam dump
  • 06:19 Fill 2678 lost during the ramp due to collimator temperature interlock on TCTVB.4L8 (B1 longitudinal blow-up not working). RF expert investigating
  • 11:30 Investigations from RF completed. Steering of the lines and filling
  • 13:16 Crash of OFSU when ready to ramp. Beam dump. Expert investigation
  • 16:26 STABLE BEAMS#2683
  • 18:02 ALICE BCM trigger - End of fill #2683
  • 20:33 STABLE BEAMS#2684

08:30 meeting

Tuesday 29 May

  • 00:46 Beams dumped by spurious QPS trigger RCBXV2.R1
  • 03:16 Beam dump during the ramp. SIS interlock due to problems with OFSU
  • 06:25 Stable beams #2675
  • 10:27 Beam dump due to QPS trip of RQ7.R1 (SEU?)
  • Recovery: dump resistor cooling time and problem with the triplet R1 power converter
  • 15:42 beams dumped due to trip of ROF/ROD.A81.B1 (ROF.A67.B1 was also not available since 15/5) leading to instabilities at the end of the squeeze (2676)
  • 17:30-20:30 Access for power converter replacement of ROF.A67.B1 and ROF.A81.B1, Quench Heater power supply of MB.C19.R6.
  • 20:30-21:30 Close machine and Pre-cycle
  • 22:00-24:30 RF control problem requiring access to replace CPU (already occurred 3 weeks ago)

Week 21 summary

Monday 28 May

  • 1:13 - 2:27 stable beams Fill 2670, 1.5e11 average bunch intensity, Peak lumi: 6.6e33 cm-2s-1, Integrated lumi ~ 27 pb-1, Emittance in collision ~ 2.2 μm rad

  • 2:27 Fill 2670 dumped by power converter problem of RQTX2.L8 (Free wheel diode fault)
  • 5:33 stable beams Fill 2671, 1.5e11 average bunch intensity, Peak lumi: 6.4e33 cm-2s-1, Emittance in collision  ~ 2.3 μm rad
  • 12:46 End of fill 2671. LSS6 BPM SW interlock (BPMS4L6.B2 )
  • Access for ATLAS until 16:30
  • Ramp #2672 lost because of LSS6 BPM SW interlock (BPMS4L6.B2 )
  • 21:58 STABLE BEAM#2673

9:00 meeting