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LHC 30 th and 31 st July 2015 07:10 Finish scrubbing fill 25 ns trains by operator dump. –No XPOC data … 08:40 Inject for another scrubbing fill 09:09.

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Presentation on theme: "LHC 30 th and 31 st July 2015 07:10 Finish scrubbing fill 25 ns trains by operator dump. –No XPOC data … 08:40 Inject for another scrubbing fill 09:09."— Presentation transcript:

1 LHC 30 th and 31 st July 2015 07:10 Finish scrubbing fill 25 ns trains by operator dump. –No XPOC data … 08:40 Inject for another scrubbing fill 09:09 Cryogenics interlock due to beam screen heating (CS R7 and L3) then vacuum valves in at P2 due to outgassing of beam screen Q6R2  pre-cycle so decided to start to long awaited / postponed injection kicker waveform scan –Missing data in Global Post Mortem 09:30 Start injection kicker MKI Point 8 waveform measurement –Thanks to LHCb for the many resets of the BCM interlock ! –At several occasions missing half the BTV screen data  reboots 16:45 Finished waveform scan: pre-cycle following cryo interlock 17:30 BLM IL thresholds increased by factor 2 on TCLA.B6R7.B1 and QI.8L2.B1 (see presentation 8:30 meeting of yesterday) 19:00 Transfer line steering with adjustment of MKI kick, both beams 21:00 TDI check 21:30 Cryo lost in matching section point 8 (without much beam)  fast precycle 00:15 Injecting 01:48 Dump on losses on long running sum TCTPV.4R2 on injection of 144 b 02:00 SPS problems (mains  RF) until this morning. Back again at 6:45 LHC Morning meeting – MG & JU131/7/2015

2 Vacuum valves in due to outgassing of beam screen LHC Morning meeting – MG & JU231/7/2015 Beam vacuum > 1e-6 mbar TDI vacuum from MKI waveform

3 Injection kicker MKI waveform scan Following change of Pulse Forming Network in TS1 to recover fast rise time –Batch spacing 1000 ns  900 ns Measured mostly the "shoulders" to save time, but measurement is very slow due to the LHCb interlock issue Results seem consistent with MKI2: –Rise time roughly 900 ns (within spec, needs precise analysis) –Ripple also within specification –Positioning of first bunch and other more detailed results to be determined after the offline analysis of the measurements Then Etienne to adjust the kicker timings and we can use the closer batch spacing LHC Morning meeting – MG & JU331/7/2015 Linda, Chiara

4 First results To be further analysed LHC Morning meeting – MG & JU431/7/2015

5 Injection Steering Further adjust MKI kick setting after BETS window re- centring 2 days ago Steer back to trajectory obtained before TS1, before PFN changes, around which TL collimators are aligned Final MKI voltage settings (BETS window is +/- 1 kv) –MKI.P2: 48530 V (BETS centre of 48730 V) –MKI.P8: 50220 V (BETS centre OF 50320 V) Reduces significantly the losses which were recently generated from the TCDIs within the vertical bump The MKI voltage reduced by a bit more than 1 kV, beneficial for reducing the probability of an MKI flashover To be done –Tighten operational limits of the MKI around these values –Update the IQC reference LHC Morning meeting – MG & JU531/7/2015 Chiara, Janet, Linda, Wolfgang

6 TDI Check Move TDI jaws separately outwards In IP8 stronger effect upper jaw movement There is a mechanism which populates the halo of beam 2 faster than beam 1 (also observed at the primaries) LHC Morning meeting – MG & JU631/7/2015 MB.15R8.B2 not far away … Benoit

7 The Plan Friday and later: –Continue some 25 ns scrubbing –Switch over to doublets possibly during the weekend or on Monday (t.b.d.) if doublets in the SPS look good and scrubbing with 25 ns standard beams is sufficiently advanced –Scrubbing with doublets As well: –1 hour to deploy and test PM / XPOC fix –Update MKI operational limits and IQC references (parasitic) Outstanding: –Injection cleaning optimisation LHC Morning meeting – MG & JU731/7/2015

8 Report from scrubbing …. LHC Morning meeting – MG & JU831/7/2015 No scrubbing in the last 24 h


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