LHC 2012 - latest news

Week 29: Machine coordinators: Eva Barbara Holzer, Joerg Wenninger

Plan for the week: Mon- Tue VdM scans, physics afterwards

Date

Summary

Link to report from morning meeting

Monday 23 July
8:30 meeting
Sunday 22 July
  • 00:30 Stable beams fill 2870, L ~5.4E33 cm-2s-1. Intensity 1.35E11 ppb.
  • 08:50 Dump by SIS after CODV communication loss for B2 (orbit excursion). Integrated L ~ 113 pb-1.
  • 10:00 Refilling - maintain same conditions.
  • 11:50 Stable beams fill 2871, L ~5.7E33 cm-2s-1. Intensity 1.35E11 ppb.
  • 16:45 Beam dumped, CMS BCM trigger. Integrated 77 pb-1.
  • Refill the same...
  • 19:00 Stable beams fill 2872, L ~5.5E33 cm-2s-1. Intensity 1.35E11 ppb.
9:00 meeting
Saturday 21 July
  • 1:06 dump of fill 2860 due to B2 losses in collision beam process.
  • 3:39 Stable beams Fill 2861. Initial L ~6.1E33 cm-2s-1.
  • 4:36 dump: BLM self-trigger IP7. integrated lumi ~19 pb-1.
  • 6:41 dump fill 2862 during collision beam process due to beam losses.
  • 8:46 dump fill 2863 after arriving at flat top: tune measurement jumped to a wrong peak and the feed-back moved B2 H tune.
  • 10:00 Diagnostics fill with 3 bunches. Measurement of the chromaticity for both octupole polarities.
  • 14:20 Dump diagnostics fill.
  • Refill with nominal longitudinal blowup in SPS.
  • 17:50 Dump due to losses at end of squeeze and in adjust on B2.
  • 19:00 Refill. Octupoles back to pre-TS2 settings for B2 in squeeze. Nominal longitudinal blowup in SPS.
  • 20:50 Dump due to losses at end of squeeze and in adjust on B2.
  • Rollback B2H chromaticity trim made at last point of squeeze.
  • Intensity down to 1.35E11 ppb.
9:00 meeting
Friday 20 July
  • 02:00 Vacuum spike in IP8 during 50 ns filling. Increased thresholds and restart.
  • 04:10 Beam dumped just after colliding due to trip of Q6.R7. Clean squeeze with more V scraping in the SPS and longitudinal blowup in the SPS switched off (by mistake).
  • Refilling - again clean squeeze, less than 1% losses on each beam.
  • 06:40 Stable beams fill 2858, L ~6.2E33 cm-2s-1.
  • 20:20 beam dumped by OP; integrated lumi ~176 pb-1
  • 22:25 dump of fill 2859 at the end of squeeze due to high losses B2 (instability).
8:30 meeting
Vacuum Pt8
Thursday 19 July
  • 08:42 Stable beams fill 2855 for Atlas and CMS VdM scans.
  • 09:00 Starting VdM scanfor Atlas/CMS.
  • 18:00 Beam dumped by SIS - beam position in TCSG6 for B2.
  • 20:50 Stable beams fill 2856 for Atlas and CMS VdM scans.
  • 00:30 Dump of last VdM fill. Switching back to 50 ns operation.
8:30 meeting
Wednesday 18 July
  • During cryo recovery: Access for Alice, Atlas, CMS, ODH P3 and P2, EPC in P4 (putting spare 600A), EPC P1 for RQTL11.L1B2, EPC pt 8, LDM in P4, and QPS board changes in P4, cryo in pt 6, CV in pt 5, ventilation door in pt2.
  • cryo filter clogged -> access in pt1
  • 13:45 crowbar RF M2B1 - this time due to a real arc in the klystron probably due to bad vacuum (access for confirmation of diagnostics)
  • 16:00 access for power converter RCBV19.R5B2
  • 16:48 cryo is back
  • 17:27 PC intervention finished, start pre-cycle
  • 21:30 - 5:30 Stable beams for VdM scans of LHCb
8:30 meeting
Tuesday 17 July
  • 00:30 Injecting for first VdM fill.
  • 01:30 Another crowbar on RF module M2B1.
  • 03:50 Stable beams fill 2852, VdM fill for ALICE and LHCb.
  • 08:00 Beam dump, again crowbar on RF module M2B1. ALICE VdM scans finsihed.
  • Access for RF module M2B1 - replace a thyratron and a smoothing capacitor
  • In the shadow access for: LHCb, Atlas, CMS, Alice, cryo to fix noisy sensor on a DFB R6, and to fix a loose vacuum interlock cable for injection kicker P8.
  • 20:30 OK from RF
  • 21:12 cryo problem in P2, lost CS and CM in sector 12.
8:30 meeting
Monday 16 July
  • 07:00 ongoing ... stable beams
  • 9:41 beams dumped by OP
  • 10:00 - 18:00 fill 2849 set-up for VdM scans including some loss map
  • 19:00 New fill 2850 for loss maps.
  • 21:00 Betatron and off-momentum dp/p - loss map done.
  • 22:00 Re-injecting for asynch dump test..
  • 23:30 Asynch dump test done.
8:30 meeting