LHC 2011 - latest news

Week 30: Machine coordinators: Gianluigi Arduini, Jörg Wenninger

Luminosity production

adiabatically decrease emittance and increase beam intensity

 

Day

Summary

Link to report from morning meeting
Monday 1st August 
  • Cryo recovery in Pt8.
 8:30 meeting
Sunday 31st July 
  • Problems to reset collimator interlocks on TCP/6R3. Piquet intervention (disable resolver).
  • Refill, RF interlock on HOM line 2 B2 at injection. Reset by RF piquet.
  • 03:50 STABLE BEAMS#1994 (working point 0.312,0.322). Initial luminosity ~2x1033 cm-2 s-1
  • 04:40: Beam dump due toRF interlock on HOM line 2 B2. End of fill #1993 - 6 pb-1
  • Refill.
  • 07:00: Fill 1995 dumped during L optimization before stable beams. Mini UFO in triplet R1 from B1. Dump by ATLAS BCM. Lumi was around 2x1033 cm-2 s-1
  • Refill.
  • 10:15 STABLE BEAMS#1996 (working point 0.312,0.322). Initial luminosity ~1.9x1033 cm-2 s-1
  • 11:20 Lost cryo compressors in Pt8 (communication)  ==> Beam dump. End of Fill #1996. 6 pb-1 in ~1 h.
  • Cryo off in Pt8.
 9:00 meeting
MKI2 erratic (M. Barnes)
Saturday 30th July 
  • 22:40 Lost cryo conditions for arc 12 (cryo-valve PROFIBUS controller in UJ16) ==> Beam dump. End of Fill #1991. 27 pb-1 in ~5 h.
  • 04:30: trip of MKI B1 during soft-start: erratic at high voltage. Investigations from expert
  • 07:00-09:00: Soft start and inject and dump verification
  • 11:50 STABLE BEAMS#1992 (working point 0.312,0.322). Initial luminosity ~2x1033 cm-2 s-1
  • 12:45: Beam dump due to loss of communication with collimator crate in UJ16 (power supply). End of fill #1992 - 5.9 pb-1 in 55 mins
  • 15:00 MKI2 erratic trigger. Access for kicker expert intervention.
  • 20:00 Recover from access.
  • Softstarts of MKI2 and inject and dump checks.
  • 21:45 refill for physics.
  • 23:00 STABLE BEAMS#1993 (working point 0.312,0.322). Initial luminosity ~2x1033 cm-2 s-1
  • 23:40 beam dumped, UFO 31L8 on B1. Integrated L 6 pb-1.
 9:00 meeting
Friday 29th July 
  • 09:00 End of fill 1990, PC trip RCBXV3.R1. Integrated L 41 pb-1.
  • Access for MKI2 main switch replacement.
  • 13:00 Inject and dump check for MKI2.
  • 17:50: STABLE BEAMS #1991 (working point 0.308,0.318). Initial luminosity 1.88x1033 cm-2 s-1
  • 22:40 Lost cryo conditions for arc 12 (cryo-valve PROFIBUS controller in UJ16) ==> Beam dump. End of Fill #1991. 27 pb-1 in ~5 h.
  • 23:30 Problem with nQPS card of B19R1 leading to spurious trips during precycle. OK after 2 resets
8:30 meeting
MKI2 erratic (M. Barnes)
Thursday 28th July 
  • 04:40 End of fill 1982, electrical glitch, dump by FMCMs.Integrated L 50 pb-1.
  • BLM connectivity problem.
  • 10:00: STABLE BEAMS #1986. Initial luminosity 1.85x10^33
  • 12:30 End of fill 1986, RF trip M1B2, klystron vacuum. Integrated L 14 pb-1.
  • Injection delayed - steering PSB-PS.
  • 16:30: MKI2 erratic during injection. 144b to TDI. Vacuum valves closed in Pt2.
  • Resume injection.
  • 18:03: MKI2 erratic again during injection. Circulating beam was hit and kicked to the TDI. Some grazing bunches quenched RD2.R2, RD1.L2 and triplet L2 and hit ALICE.
  • 22:00 Resuming injection with inject and dump mode.
  • 23:00 Transfer line steering in TI2 with 12b.
  • 24:00 Filling for physics.
  • 01:20 Stable beam fill #1990, Initial luminosity 1.9x1033 cm-2s-1.
8:30 meeting
Wednesday 27th July 
  • 03:30 Stable beam fill 1982.Initial luminosity 1.7x1033 cm-2s-1.
  • 06:00 End of fill, FMCM trigger, electrical network glitch. 13 pb-1.
  • Injection delayed due to problem with the SPS injection kicker
  • 09:00 LHC Controls problems
  • 11:00 Injection: vacuum rise in point 2 leading to beam dump. Possible outgassing at the ion pump switch on
  • Re-steering and re-inject ==> Beam dump due to vacuum raise close to D1.R2 during the squeeze ==> Increased threshold for the corresponding vacuum gauge to allow outgassing
  • 17:20: STABLE BEAMS #1985. Initial luminosity 1.76x10^33
 8:30 meeting
FMCM triggers (M. Zerlauth)
Tuesday 26th July 
  • 04:30 QPS trip on RCO/RCD/RCS.A56. End of fill #1979 after 6 h (~23 pb-1)
  • Following fill lost during the ramp (QPS trip – RQTL7.R7B1)
  • 07:00: Trip of Sector 12 during ramp down
  • 08:30 Access for QPS problems and RF + experiments:
    • Filters installed for crowbar control electronics on 3 out of 4 RF modules (one was already installed) to avoid spurious trips
    • Broken power supply on old QPS in 14L2 identified as origin of the trip of Sector 12 ==> replaced
    • Replaced QPS cards on RCO.A56.B1 and RQTL7.R7
  • 23:00 LHCb polarity switch (Pol +, large total Xing angle)
 8:30 meeting
Monday 25th July 
  • PROFIBUS controller problem (SEU) on cryo valve on DFBMH (600 A circuit RQ6.L7B1/2). Loss of cryo maintain ==> Beam dump. End of fill #1975 after ~2.5 hours (13 pb-1)
  • 14:30. Beam dump (fill 1976) due to BLM on TCSG.L7B1 while going in collision (long running sum). Emittances slightly smaller from the injectors.
  • Increased BLM threshold on BLMs on TCSG.L7B1
  • 18:00 Verification of the effect of solenoids on vacuum in point 8. No effect on vacuum pressure in D1.L8
  • 18:30 beam dump due to RF trip at the end of the squeeze (fill 1977)
  • Issues when reinjecting (verification of transfer line trajectory and BLM spurious dump)
  • 22:30 Stable beams #1979: Initial luminosity 1.3x1033 cm-2s-1. Larger emittance from the injectiors
 8:30 meeting