07/08/2010 Fill #1264 dump at 02:14:38

07/08/2010 Fill #1264 dump at 02:14:38: BLM @Q11.L4B1 (2.5 ms threshold triggered) . The comparison with a BLM at TCP.L7 indicates that the loss is real, similar time behaviour

07/08/2010 Beam loss comparison at TCPs for beginning of fills 1264 (left) and 1263 (right). Little more activity at the very beginning Power converters within tolerance No tune changes, trajectory changes before the loss

07/08/2010 Losses for fill 1262 and 1264: both with no Q-split Improvement with respect to 1262 G. Papotti

07/08/2010 Observed inconsistency in timing of BLM patterns w.r.t. Beam interlock timing will be fixed by BLM team on Monday with new firmware release BLM @ TCDS.4L6B1 BLM @ Q11.L4B1

07/08/2010 Compensator filter at point 2 fixed by 09:50 RQ8.R6B1 took most of the day to be fixed with the power converter and MP3 experts: difficult diagnostics. Initially thought to be a QPS problem finally it turned out to be a problem with the power converter inducing QPS trips. Sudden current drift due to problem on one of the power modules suddenly sending a voltage spike

Regular spikes (300 s) in the U-res signal 07/08/2010 QPS tripping as a result of the sudden current change putting the QPS boards in a wrong state QPS boards replaced Faulty power module disconnected at 16:30 finally solving the problem In the mean time access given to ALICE/ATLAS/CMS in the shadow Regular spikes (300 s) in the U-res signal

07/08/2010 19:00 Machine pre-cycled, injection Small emittances although previous verification in the SPS gave emittances closer to 3 mm. Measured ~2.2 to 2.6 at 1 TeV  work ongoing today to re-optimize the blow-up Corrected chromaticity at the end of the squeeze (although very difficult to measure in the H plane due to the presence of several spikes close to the tune). Measured ~9 units in H plane and 3 units. Corrected down to 2 units in both planes

07/08/2010 23:10 STABLE BEAMS After optimization: ~4x1030 cm-2s-1

07/08/2010 Lifetimes

07/08/2010 Relative losses for fill 1264 and 1266. Both with NO tune split. 1266 initial losses lower than all other fills

07/08/2010 01:10 dump due to BLM in 15.L5 (2.5 ms threshold) Preliminary observations: The pattern is similar to that observed for fill 1264 Losses occurring in ~3 ms Trajectory OK Went for another fill after increasing the transverse emittances in the SPS (still being optimized): B1:2.5/2.5 – B2:2.6-4.0

07/08/2010

07/08/2010

Plan Keep this fill

Pending Tests: Requiring access: New BLM Firmware tests Delay of the PM trigger of the BLM system to be set back  BLM team ready only next week Loss maps, orbit clean-up and TCT verifications Requiring access: Repair COD MCBH.18R7.B2 CV need to replace a motorisation of the water valve of the sector 56 - not urgent Time estimate ~3 hours Access team to replace oxydized connectors for PAD-PX24 in case of stop (3 hours) Magnetic probes in the machine for the studies related to the hump - access in point 5 (GA, LW) – 3 hours

Open issues Open Issues: Clogging of CMS cryo filters not yet understood Vacuum pumps near dilution kicker. QPS boards: several boards had to switch from channel A to B