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Thursday 12 August - Morning

Thursday 12 August - Morning. Regenerated chromaticity / sextupole functions for the squeeze and re-trimmed knob functions using matched data points only. Current functions now smooth throughout - Aarush & Mike Asynchronous beam dump analysed – all O.K. - Wolfgang – Chiarra - Jan

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Thursday 12 August - Morning

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  1. Thursday 12 August - Morning Regenerated chromaticity / sextupole functions for the squeeze and re-trimmed knob functions using matched data points only. Current functions now smooth throughout - Aarush & Mike Asynchronous beam dump analysed – all O.K. - Wolfgang – Chiarra - Jan 9:00–12:00: Preparation for the 10A/s ramp - cured some issues SPS-LHC RF re-synchronisation problem: preventing injection for the Ramp10Aps  resolved by trimming the RF freq. The RF team is looking at what is done in the re-synch sequence. Andy and team To note: for the Ramp10Aps, the longitudinal blowup during the ramp will not work at present, and so if the ramp is retried, the task should be skipped – Elena and team 12:00 : Ramp function ready to load after a slight increase in the rate limit for the RQXs in pts 2 and 8 (which required to dump the beams)

  2. Thursday 12 August  XPOC error on B1; the TCDS beam loss bar appears in red on the LBDS display

  3. 450 GeV optics measurements – B1 Rogelio Tomas and team

  4. 450 GeV optics measurements – B2 Rogelio Tomas and team

  5. Thursday 12 August - Afternoon • Continuous series of problems: • MKI-B1 erratic problem – quickly fixed (reset) • Lost cryo-maintain in S23 -> access required in UJ27 to check a DFB valve which was blocked • QPS OK lost for the RB, RQD, RQF in A12 : RAID disk problem on the PVSS server for the nQPS. A reboot was required but with the circuits switched to off, followed by a rebuild of one of the RAID disks. After the reboot, the nQPS functionality was recovered • … leading us to 18:30 so stopped the progress on the 10A/s ramp and recovered the 450 GeV condition to launch a physics fill

  6. Thursday 12 August In the shadow: BLM tests without beam: Temporarily deployed a TEST firmware to all processing electronics that will push ramp vectors in the PM and XPOC buffers. Send few events to test the BLM XPOC buffers. Reloaded operational version of the firmware and checking that all cards run this version 19:00 – injecting, 1x1, ~3e10 for beam dump test  TCDSA below threshold, but still higher than expected. Analysis and understanding on going. 19:30 – 20:30: Injecting 25b x 25b. SPS measuring 2.7um in both planes. Measure less in LHC (less than 2 um….).

  7. Thursday 12 August 22:20 : Beam dump right before collisions – RCBXH1.R2 tripped. Investigation:  the demanded current is obtained through a V_ref of 90 mV, which is immediately caught by the QPS. It seems that an offset is present on the U_res, which, once added, might just enough to exceed the 100 mV. M. Zerlauth --> made a reset. related to some spikes popping up from time to time on QPS system? checking with EPC piquet  nothing anomalous was detected at the level of the PC

  8. Thursday 12 August Voltage seen by the QPS Demanded current

  9. Thursday 12 August Restarting the whole process – RCBXH1.R2 tripped again Tried to repeat the event by powering the circuit RCBXH1.R2 through equipment state and then sending the Physics function: the circuit does not trip! Repeat it -> tripped Circuit RCBH1.R2 is at the limit of ramp rate and/or acceleration. As soon as we drive the function (which was refined in the last days), it trips. Changing the function would work for this time, but maybe not for the next one  better to reduce the ramp-rate/acceleration or increase the 100mV threshold? Need to be addressed with expert this morning.

  10. Thursday 12 August 1bx1b, for loss maps on momentum -> last remaining test for “weekly” collimator checks (not done since some weeks now)

  11. Plans for next days • Friday : • 8:00 – 8:30 : Loss maps • 8:30 – 9:30 : Ramp down • 9:30 – 12:30 : 10A/s ramp • 12:30 – 15:30 : Access • Then : refill for Physics • Week end : Physics

  12. Access • COD (Miguel CerqueiraBastos) • RCBH12.L1B1 RCBH12.L1B1 - warning PSU - • RCBV29.L4B2 - warning Imeas • RCBH34.L7B1 - the converter was changed in 3/06/2010 - we informed operation at the time: the converter is ready to be used • Next TS: RCBH18.R7B2 • RPMC.UJ33.RCBCV6.R3B1 - change an auxiliary power supply

  13. Access • BSRT – Access in point 4 US45 – 30mn - Federico Roncarolo • ATLAS – Access in US15 – 15 min • ADT : UX45 - ~1 hour. check remote reset and the rf multiplexor – Daniel Valuch • Fast BCT – Pt 4 – change attenuators -David Belohrad • IP6 UA63 :CPU in CFV-UA63-BCTFD crate to change -David Belohrad • Monday: CV need to replace a motorization of the water valve of the sector 56 - not urgent ~3 hours • Monday: Access team to replace oxydized connectors for PAD-PX24 in case of stop (3 hours) • Monday: Magnetic probes in the machine for the studies related to the hump - access in point 5 (Louis Walckier) – 3 hours

  14. Issues • MONDAY – Clogging of CMS cryo filters not yet understood  ACCESS 10h • QPS boards: several boards had to switch from channel A to B. • BLM racks (in buildings SR1 and SR5 and both at position BY02): would like to correct the way the power cable for the multi-plug arrives inside the rack. • Ion pumps in dump line MKB (B2 only 4 out of 8 pumps working; few days intervention, next TS) • Bunch-to-Bunch diagnostics would be very helpful! • Noise on BBQ in tune spectra • Origin – cause of the beam losses that terminated 2 of the best runs (beam-beam?; coherent versus incoherent?).

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