LHC 2012 - latest news

Week 32: Machine coordinators: Mike Lamont, Jan Uythoven

Plan for the week: Luminosity production & octupole polarity change.

CMS had a fast abort of their solenoid on Friday morning. 3 to 4 days to recover. In the meantime we will bring forward planned operational development to minimize loss of luminosity. Program for the next few days follows.

Friday morning Octupole polarity/ SPS wire scanner repair
Friday afternoon Octupole polarity/ SPS wire scanner repair
Friday night Switch LHCb polarity - test ramp - if SPS vacuum OK
Saturday morning Test ramp for chromaticity measurements through the cycle till ~12:00
Saturday afternoon New SPS optics (Q20) to LHC
Sat night New SPS optics (Q20) to LHC
Sunday morning High intensity tests with normal setup
Sunday afternoon Transverse damper tune measurement tests
Sunday night Physics
Monday Switch ALICE polarity - 24 hour program (injection, tertiary collimators through the cycle, loss maps)

 

 

Date

Summary

Link to report from morning meeting

Mon 13 Aug
  • 00:00 Stable beams Fill #2927, intial lumi's 6.85e33 cm-2s-1
  • Beams dumped by an interlock on TCTs in point 1. Integrated lumi 152 pb-1
8:30 meeting
Sun 12 Aug
  • 07:05 Ramp 2 x 2 x 144 bunches, injected with Q20 optics: all fine
  • 07:51 Dump fill #2950
  • BPMS interlock during injection
  • 12:33 Ramp with 2 x 1374 bunches, 1.55e11 ppb, stability checks
  • 17:01 Dump beam
  • 17:55 Injecting for ADT tune measurement test
  • 19:37 Ramp for ADT
  • 21:26 Dump ADT fill
  • 23:12 Ramp for physics fill #2957
9:00 meeting
Sat 11 Aug
  • 01:30 SPS kickers conditioned and ok but PS 40 MHz cavity down
  • 03:37 Injecting probes n05:24 Ramp with LHCb polarity switched to negative, CMS solenoid off
  • 07:00 Optimising collisions
  • 08:35 Beams dumped, LHCb dipole tripped
  • 10:34 Start test ramp for chromaticity measurements.
  • 11:33 Beams dumped, prepare for SPS Q20 injection into the LHC.
9:00 meeting
Fri 10 Aug
  • 08:20 Beams dump. CMS solenoid emergency ramp down due to cryogenics problems.
    Integrated lumi 133 pb-1.
  • 10:15 Octupole polarity measurements with beam.
    SPS wire scanner exchange in parallel
  • 19:58 End of measurements, beams dumped
8:30 meeting
Thu 9 Aug
  • 01:48 Beams dumped. RB energy check went false, SMP energy glitch? Integrated lumi 94 pb-1   
  • 05:35 Stable beams Fill #2932. Initial lumis 6.5e33 cm-2s-1
  • 11:52 Beams dumped, SIS triggered following network issue in CCR. Int. lumi 103 pb-1.
    Going for access, while SPS is still down for EDF intervention.
  • 12:30 Access
  • 16:30 Start pre-cycle
  • 20:23 Fill #2933 dumped. Losses end of squeeze and adjust. Vertical tune B2 hits third order resonance. Lower tune for next fill.
  • 23:25 Stable beams #2934. Initial lumi 6.5e33 cm-2s-1
8:30 meeting 
Wed 8 Aug
  • 01:25 Stable Beams fill #2927, 1374 bunches (vertical instability end of squeeze)
  • 09:31 Operator dump.Int. lumi 103 pb-1
  • 12:10 Stable beam fill #2928, still vertical instability end of squeeze. Initial lumi 6.2e33 cm-2s-1
  • 14:28 Beams dumped by QPS trigger on RQSX3.R1. Probably SEU. Int. lum 45 pb-1.
  • 20:03 Stable Beams Fill #2929. Init lumi 6.3e33 cm-2s-1, still some instability squeeze B2V at ~1.5 m beta star, but starts to look better.
8:30 meeting
Tue 7 Aug
  • 00:24 Operator dump. Integrated lumi around 68 pb-1.
  • 02:41 Fill #2919. Beams unstable throughout the squeeze. Lost on HV BLM 
  • 05:05 Fill #2920 Stable Beams. Lumi’s around 6.3e33 cm-2s-1 (!), although some losses in squeeze.
  • 06:20 Dump due to ALICE BCM. UFO…
  • 08:10 Fill #2921 Dumped at start of ramp. Beam losses on TDI IP8 which got stuck when moving out after injection, resulting in a large angle.
  • Switch octupole polarity: 450 GeV tests; test ramps - pilot, 12b;
  • 21:21 Stable beams fill #2926 480 b
  • 22:48 Operator dump
8:30 meeting
Mon 6 Aug
  • 01:53 start injecting fill 2915, average bunch intensity 1.53E11, good ramp and squeeze
  • 03:13 dump on instability 70 sec after the collision beam process was launched due to RS9 losses on TCTH.4R5.B2
  • 03:52 changing the thyristor did not solve the problem with the ALICE solenoid à is staying off
  • 04:20 SPS extraction kicker problem - access in the mean time. ALICE solenoid fixed.
  • 13:00 Pre-cycle by running nominal ramp with reduced octupole currents in the ramp.
  • 15:00 Injecting physics beams fill #2917.
  • 16:21 With squeeze finished beams dumped due to ALICE interlock. ALICE BCM dumped with values 300 % of threshold. Expect UFO.
  • 17:48 Injecting for physics, fill #2918
  • 19:07 Stable beams. Low initial lumi's of 4.5e33 cm-2s-1 due to blow-up of bunches end of ramp with octupoles at 150 A.
8:30 meeting