LHC 2011 - latest news
Week 46: Machine coordinators: Ralph Assmann, Jan Uythoven
Goals of the week: Establish high intensity Pb-Pb
physics. Test p-Pb physics.
Link to report from morning meeting
Monday 21st Nov
- 08:45 Cryogenics S34
back. Problems access doors.
- 10:30 Injecting pilot.
Sunday 20th Nov
- 02:43 Stable
beams Fill #2308.
- 09:27 Beam dump by
- 12:53 Stable
beams Fill #2309
Initial lumi (Atlas) 4.25e26 cm-2s-1
- 14:30 Life time of
beams suddenly going down, recovered in few minutes
- 17:29 Beam dump,
preventive dump, loss cryo maintain S34.
Cold compressor trip Point 4.
- 19:00 Intervention for
MKD switch replacement to be done now, teams preparing Also EPC imtervention
on RCBCV10.R3B1 is set for 8pm
Saturday 19th Nov
- 05:15 Beam dump by
- 08:10 Stable
beams Fill #2305.
- 11:08 Lost QPS ok in B11.L1 (location of ion
losses). QPS piquet called.
- 14:24 Beam dump. XPOC
Beam1 blocked due to BLM: BLM on TCDSA is reproducibly just over
- MB11.L1 QPS power
- 16:33 Injection. Missing
batch/low intensity batch when injecting. Dump and re-inject.
- 19:56 Adjust.
- 20:04 Beams dumped. low
filament current on RF line 2B1 caused module M1B1 to trip.
- 21:53 RF intervention
finished after reset of regulator on klystron.
- 23:45 RF filament
current error on cavity 2B1 at flat top. Keep cavity 2B1 off. B1 RF
voltage reduced from 14MV to 12.2MV.
Friday 18th Nov
Stable beams. Fill
- 06:07 Beam dump by RF
temperature interlock (HOM 4B2). Total delivered Pb-Pb
lumi in 2011 reached 19.6 ub-1 in ATLAS.
- 09:34. Stable beams. Fill #2303.
- 14:48 Beams dumped.
Spurious opening of the quench loop on the RQF in S12
- 16:35 QPS access for
the switch on RDC.A12B2 . ALICE also in.
- 18:30 end of access
- 22:41 Stable
beams Fill #2304
Thursday 17th Nov
- 09:00 Dumped beams,
refill for Pb-Pb physics. No more protons in 2011…
- Increase of flat top
total voltage to 14 MV. Feed-forward on the H orbit CODs in the ramp and
squeeze. New version of the FBCT.
- Release of SIS. The
only change concerns the injection bucket check. The logic now allows
injection if there is a lone single bunch in the machine beyond the
point of the incoming injection.
- 11:00 Problem on dump
kicker B1, one swithc is dying and may need to
be exchanged. It has been masked for the time being to allow to go in
- 12:56 Stable beams. Fill #2301.
- 13:47 Changed the
settings on the acquisitions for the BQMLHC so that the pattern for ring
2 is not detected incorrectly at the flat top (so far at times the last
batch was detected 1 bucket aside). The acquisition was always ok at the
flat bottom, where it is vital...
- 18:46 change the
target length for the blow up from 1.05E-9 to 1.25e-9 for both beams. We
will have longer bunches for the next ramp.
- 19:22 Ramp down undulators for BSRT tests.
- 19:59 Adjust mode: end
of stable beams. 4.2-4.8ub-1 delivered per experiment. Test of lumi scan software changes for 25min. Some bug found
-> not yet deployed.
- 20:30 Beam dump. CMS
access during ramp down and cycle.
- 21:08 Undulator is back on.
- 23:41 Ramp.
Wednesday 16th Nov
- 00:05 Preventive beam
dump due to cryo problem in 34. Fault on the power
converter for the cold compressor. Collected 4-4.5 mb-1 per experiment in fill
- 09:15 Cryo conditions
- 12:20 PS Septum
problem - no beams available for a while...
- Decide to go back to
Pb-Pb for the night
- 20:45 Injecting Pb
LHCb gas injection
Tuesday 15th Nov
- 00:20 Start ramp
- 01:30 Stable beams,
fill #2294 170 x 170 bunches. Lumi up to 1.5e26.
- 08:25 Beams dumped due
to RF vacuum interlock
- 09:53 Triplet R2 power
converter problem, access required
- 11:50 Access required
for the RF vacuum point 4.
- 13:50 Start pre-cycle
- 16:20 Injection
- 17:15 Filled 358 on 358
bunches. Nominal ion intensity.
- 17:23 Ramp.
- 17:43 Squeeze.
- 18:22 Stable beams.
Fill #2297. Peak luminosity: 3.5e26 cm-2 s-1. 1.8MJ of stored energy per
- 22:29 G. Schneider is
going to start the injection of gas in LHCb.
- 10:00 PS vacuum about recovered
- 11:30 Injecting probes
- Several problems on
the injector chain in the afternoon and evening plus some time for
setting up injection in the LHC