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Transfer line test: Beam stability measurements

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Presentation on theme: "Transfer line test: Beam stability measurements"— Presentation transcript:

1 Transfer line test: Beam stability measurements
TI 8 trajectory stability TI 2 trajectory stability SPS orbit stability by Eliana MKE.4 waveform scan MKE.6 waveform scan + IQC status

2 Reminder: Large shot-by-shot transfer line trajectory variations in the horizontal plane discovered in 2011 Investigations revealed the SPS extraction septa as the main source for both lines. At the end of 2011 work was started to improve the power converter of the MSE.6 (TI2) which lead to improved stability. Work continued on the MSE.4 during LS1.

3 Transfer line test: TI 8 Trajectory stability studies
246 trajectories analysed :30: :21:15 Removed BPMI BPCEs

4 TI 8: Model Independent Analysis gives 1 source which matches MSE
TI 8: Model Independent Analysis gives 1 source which matches MSE.4, but..

5 TI 8: The strength has been reduced by almost a factor 2
APRIL 2012 NOVEMBER 2014 APRIL 2012 (Q26) NOVEMBER 2012 NOVEMBER 2014 RMS H [mm] 95.6 - 73.9 RMS V [mm] 62.6 63.5 Eigenvalue #1H [mm] 72.9 42.2 MSE stD [A] 4.5 3.9 2.1 MSE stD [1e-3] 0.20 0.18 0.10

6 Transfer line test: TI 2 Trajectory stability studies
256 trajectories analysed :34: :12:59 Removed 5 BPMIs + BPCEs

7 TI 2: MSE.6 is the main source

8 For TI2 the stability of the MSE
For TI2 the stability of the MSE.6 was already improved during LHC Run I by a factor 2 JUNE 2011 APRIL 2012 NOVEMBER 2014 JUNE 2011 (Q26) APRIL 2012 (Q26) NOVEMBER 2012 NOVEMBER 2014 RMS H [mm] 92.1 83.0 - 74.2 RMS V [mm] 35.1 64.4 63.4 Eigenvalue #1H [mm] 86.0 54.4 38.9 MSE stD [A] 3.6 2.4 1.9 1.8 MSE stD [1e-3] 0.18 0.12 0.10

9 Eliana has analysed the SPS orbit data from the transfer line test and the weekend after
Data sets: #1 Friday November #2 Saturday November #3 Friday 28. November #4 Saturday 29. November #5 Sunday 30. November * A selection of plots, see more in attached slides

10 Within each set the orbit is stable
V SPS mains switched off for 7 min at set #25, step in V at #30 Eliana Gianfelice

11 Large orbit difference between set #2 and set #1
Correct set #1 back to set #2 reference: Best corrector: MSE with ~ -18 mrad Fourier analysis give peak at 21, tune was off by +0.5 Eliana Gianfelice

12 Large orbit difference between set #3 and set #2 (~1 week)
Correct set #3 back to set #2 reference: Best corrector: MBA (180 counts) with ~ -9 mrad Eliana Gianfelice

13 No significant correction between set #4 and set #2
Correct set #4 back to set #2 reference: Eliana Gianfelice

14 No significant correction between set #5 and set #2
Correct set #5 back to set #2 reference: Eliana Gianfelice

15 Reminder: Why waveform scans?
IQC Injection Oscillations per bunch - B2 Horizontal plane Vertical plane Large bunch-by-bunch variations 12 bunches not representable for correction

16 Reminder: MKE.4 waveform scan from October 2011
Error bars: 0.5 murad Difference over 144 bunch injection: p2p = 12.1 mrad, avg = 2.8 mrad Difference to 12 and 144 bunches: 4.7 mrad

17 Reminder: Delay changed from 54 to 53.2 ms for 2012 run
400343 Difference over 144 bunch injection: p2p = 8.1 mrad, avg = 2.5 mrad Difference to 12 and 144 bunches: 0.6 mrad (1.5 mrad for 6 bunches)

18 2014 MKE.4 waveform scan Proposed delay 48.1 ms
Screen BTV (400105) Error bars: 1 murad Proposed delay 48.1 ms Difference over 144 bunch injection: p2p = 6.8 mrad, avg = 1.7 mrad Difference to 12 and 144 bunches: 0.6 mrad (0.2 mrad for 6 bunches)

19 Comparison of scans to lab measurements:
Beam scans: June 2009: five unserigraphed magnets (5U+0S); Oct. 2011: magnets #2 & #3 serigraphed, #1, #4 & #5 unserigraphed (3U+2S); Nov. 2014: five serigraphed magnets (5S). Mike Barnes

20 LSS4 Layout - Summary Prior to Dec 2010: no MKE4s serigraphed.
#2 & #3 exchanged for serigraphed versions 12/2010. #4 & #5 exchanged for serigraphed versions 12/2011. # exchanged for serigraphed version 04/2013. 41631 41634 41637 41651 41654 L1 L9 S6 S4 L5 Double foot H20 in PFN Single foot TMR BEAM Magnet #1 Magnet #2 Magnet #3 Magnet #4 Magnet #5 VPIB_41632 VPIB_41633 VPIB_41635 VPIB_41636 VPIB_41638 VPIB_41639 VPIB_41652 VPIB_41653 VPIB_41655 VPIB_41656 Serigraphed from 12/2010 (was L5) Serigraphed from 04/2013 (was L2) Serigraphed from 12/2011 (was S7) Serigraphed from 12/2011 (was L1) Serigraphed from 12/2010 (was S4) Prior to April 2013: L1 was L2 (not-serigraphed) Prior to December 2011: S4 was S7 (not-serigraphed) L5 was L1 (not-serigraphed) Prior to December 2010: L9 was L5 (not-serigraphed) S6 was S4 (not-serigraphed) On December 15, 2010: Faulty Ion Pump VPIB_41632 replaced Faulty Ion Pump VPIB_41635 replaced Faulty Penning Gauge VGHB_41655 replaced Mike Barnes

21 2014 MKE.6 waveform scan Proposed delay 38.5 ms
Delay setting during 2014 scan: 40 Error bars: 2 murad Screen Proposed delay 38.5 ms Difference over 144 bunch injection: p2p = 9.4 mrad, avg = 1.7 mrad Difference to 12 and 144 bunches: 1.6 mrad (0.1 mrad for 6 bunches) * Probably smaller as measurement error is around ±2 mrad

22 IQC data collection, analysis and GUI running smoothly
IQC data collection, analysis and GUI running smoothly ..a few issues to be followed up: LHC Beam Loss Monitors: still some new monitors not installed 1 (of 12) LHC BPM crate not giving data (bad timestamp) Transfer line BCT sometimes give wrong result  set correct sensitivity setting from sequencer Few issues in analysis/panel  small updates in SCRAPER, BLM and FAST RESULT modules Check Fast result with injection sequencer Thresholds not updated (BLMs, MKIs etc.)

23 Summary Shot-by-shot trajectory variations:
MSE.8 current stability improved by a factor 2 during LS 1 MSE.6 current stability improved by a factor 2 during Run I SPS orbit has very small variations within this time, but changes over time need to be further investigated Bunch-by-bunch trajectory variations: MKE.4 waveform improved, but not as much as expected Optimised delay: 48.1 ms MKE.6 waveform is flat (no change) Optimised delay: 38.5 ms


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