LHC 2012 - latest news

Week 19: Machine coordinators: Gianluigi Arduini, Mike Lamont

Plan for the week: Luminosity production

 

Date

Summary

Link to report from morning meeting

Monday 14 May
  • 00:03 UFO at BLMQI.06R8.B2E10_MQML. Beam dump
    Re-steering required for TI2
    03:28 STABLE BEAMS #2627. 1.27e11 ppb, 4.11e33 cm-2s-1

 8:30 meeting

Sunday 13 May
  • 03:50 start ramp
  • 04:25 Stable beam #2623 1.23e11 ppb, 4.13e33 cm-2s-1.
  • 8:15 cold compressor off in point 2...
  • 09:50 Beam dumped by operations - cryogenics recovery required
  • 15:00 Cryo back, pre-cycle etc.
  • 18:00 Start ramp #2624
  • 18:54 Stable beams #2624. 1.28e11 ppb, 4.34e33 cm-2s-1
  • 18:54 Stable beams #2624. 1.28e11 ppb, 4.34e33 cm-2s-1

 9:00 meeting

Saturday 12 May
  • OK form MP3 to re-start
  • 01:16 Temperature of RB dump resistor OK but problem with orbit corrector RCBCV9.L5B1 (120 A) requiring access for repair
  • 03:30 Access finished – pre-cycle
  • 04:30 – 07:00 Losses at injection on beam 2. Finally traced back to different super-cycle in the SPS
  • 08:48 STABLE BEAMS #2621. Initial luminosity 4.2E33 cm-2s-1. 1.22e11 p/b
  • 22:05 End of stable BEAMS#2621. OP dump. 120 pb-1 in ~13 h
  • Fill #2622 lost while going in collision due to high beam losses

 9:00 meeting

Friday 11 May
  • 00:20 trip of 2 vacuum gauges leading to trip of transverse damper (VB1 and HB2). Not able to switch it ON.
  • 01:03 beam instability developing and beam dump
  • High losses during injection
  • 06:20 Ready to ramp but problems in loading RF FGC (communication)
  • 08:00 RF communication problem solved. Ready to inject but beam not available from the injectors.
  • Injection line collimators opened from 4.5 to 5 sigmas
  • 10:40-11:40 Access required for RF
  • 12:30 Finally injecting. 1.34x1011 p/bunch
  • 14:04 STABLE BEAMS #2616. 1.25x1011 p/bunch. 4.3x1033 cm-2s-1.
  • 15:57 Failure of a 24V power supply for vacuum control crate in point 7. Beam dump. End of fill #2616.
  • 17:00-20:30: access for vacuum, cryo instrumentation in point 2, World Fip repair in Sector 78
  • Precycle
  • 23:20 STABLE BEAMS #2617. 1.22x1011 p/bunch. 4.1x1033 cm-2s-1
  • 23:40 Trip of Sector 12 (Q7.R1 and Q9.L2. Quench Heaters fired. SEU?) End of fill 2617.

 8:30 meeting

Thursday 10 May
  • Smooth squeeze but beam unstable going in collision in spite of higher damper gain (factor 2). The beams are still separated by 1-2 sigmas at the end of the collision process.
  • RF controls problem and problems with the BLM sanity check.
  • Fill with 12 bunch trains to determine head on collisions in 1 and 5.
  • 09:17 STABLE Beams #2605 with 480 bunches
  • 10:30 Test to separate IP1/5. Beam instability developing
  • 10:49-12:20 Access for ATLAS and intervention on ALICE dipole power converter
  • 13:00-16:00 Injection setting up (no beam from PSB for 1/2 hour)
  • 17:35 STABLE BEAMS #2608. 1380 bunches. Initial luminosity 3.9x10^33 cm-2s-1
  • 18:06 Beam dump due to UFO in MKI2
  • 20:40 STABLE BEAMS#2609. 1380 bunches. Initial luminosity 3.7x10^33 cm-2s-1

 8:30 meeting

Wednesday 9 May
  • Cryo recovery
  • 17:50 Cryo almost recovered but electrical problem in point 1 affecting ATLAS and to minor extent LHC: trip of RD1.LR1 and ventilation doors status as opened
  • 18:30 Cryo OK
  • 20:20 Electrical network in point 1 OK.
  • 20:20 Trip of ALICE dipole and access for flammamble gas detection system in US15.
  • 21:20 ALICE dipole and gas detection system OK. Prepare for pre-cycle. In the shadow RF control problem on cavity 8B2 requiring piquet intervention and reboot of a control crate
  • 21:52 Trip of RB.A12 when starting pre-cycle.
  • 21:56 Finally starting pre-cycle
  • 22:26 Unable to switch ON RF cavity 1B1
  • 23:47 Finally injecting

 8:30 meeting

Tuesday 8 May
  • 09:08 Adjust collision point by longitudinal displacement (~15 mm) in adjust mode
  • 09:20 OP dump: End of fill #2596
  • Feed-forward on orbit during the squeeze from high gain feedback run yesterday
  • 11:00-13:00 Issues with the beam quality in the SPS and BPM re-phasing
  • 13:15 Trip of RQTL11.L5B1 (already occurred during the week-end). Access for replacing the power module. In the shadow access for LHCb and BPM in LSS6.
  • 13:15-15:30 Access
  • 15:30-17:30 Pre-cycle and re-commission RQTL11.L5B1
  • 17:30-18:30 BPM LSS6 check after repair
  • 18:50-20:30 PSB problem. Injection stopped.
  • 20:30 Finally filling
  • 22:01 Beam dump when in collision - instability (mostly horizontal)
  • 23:15 Cold compressor trip in point 8 (sector 78)

 8:30 meeting

Monday 7 May
  • 00:00 Stable beam fill 2592, 1092 b, 3.2E33 cm-s-1
  • 01:15 Dump by FMCM, electrical network glitch.
  • Refill, but with higher bunch charge ~ 1.4E11.
  • 04:30 Beam dumped in the squeeze, losses on Q4.L6.
  • Yet again… 1092b.
  • Survived the squeeze by miracle – 94% of dump threshold on Q4.L6
  • 06:40 Stable beams fill 2593, 1092b, 3E33 cm-s-1
  • 11:14 Beam dump. FMCM another electrical network glitch
  • Reverted to transverse feedback settings before the technical stop
  • 12:40-15:00 Injection checks. Verification of the scraping in the SPS ==> H-scraping not working properly ==> switch to spare scraper
  • 15:00-17:30 High bandwidth orbit feedback test
  • 17:30-18:30 Check of the alignment of TCPs in point 7 and TCSG in point 6
  • FMCM check (RD34.LR7)
  • 19:00-21:00 Issues with RF control problem and BPM LSS6
  • 22:36 STABLE BEAMS #2596. 1092 b. Initial luminosity ~3.6e33cm-2s-1

 8:30 meeting