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#3224 Sat 17 th November

#3224 Sat 17 th November. Restored an “AP” set-up with some measurement of Twiss. The idea was to take some BPM data with a known twiss set-up to see how the bunch-to-bunch position variation correlates with the T wiss. Took BPM data in AR1. Scanned AR1-Q1/4 to close dispersion

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#3224 Sat 17 th November

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  1. #3224 Sat 17th November • Restored an “AP” set-up with some measurement of Twiss. • The idea was to take some BPM data with a known twiss set-up to see how the bunch-to-bunch position variation correlates with the Twiss. • Took BPM data in AR1. • Scanned AR1-Q1/4 to close dispersion • Scanned AR1-Q1/4 to make isochronous.

  2. #3224 Twiss • AP set up from #3139 • See \\Dlfiles03\alice\Analysis\Period 14 data\AP_period13and14\transversemodel\3139 • Repeated the same scans to compare Twiss repeatability. • ST1-Q1 scan Q2 = 0.6 A Q3/4 = 0 A • ST1-Q2 scan (0-1.4A) with Q1 = 0.40A.

  3. ST1-Q1 scan Q2 = 0.6 A Q3/4 = 0 A, beamsize measured on ST1-4 Yuri original meas’t on #3139 #3224. Position of minimum looks similar but curve much shallower My analysis of #3139

  4. ST1-Q2 scan (0-1.4A) with Q1 = 0.40A. beamsize measured on ST1-4 No plot available from Yuri’s file My analysis of #3224 My analysis of #3139

  5. Twiss Calculation Uses parabolic fit to σ^2 vsk.l Constrain parabola vertical offset to smallest beamsize measurement

  6. Twiss Conclusions • NB: I didn’t go to divisor 20 like Yuri did. But I would expect the result (if any) of this would be to make my beamsizes on #3224 larger due to increased beam loading. However, my beamsizes are smaller. • I set up phases “accurately” to match #3224 60pC; BC=-10/+15deg; Lc = crests. Pb=1.2kW. • Comparison of the quad scan data suggests optics are not highly repeatable. Two months gap between measurements being compared. Maybe this is too long a gap.

  7. Model vs Measure #3224 ST2-2 AR2-1 ST1-3 ST2-1 Model/measure agreement not too bad

  8. Bunch intra-train variation/jitter compared with β function x-plane AR1-BPM-01 AR1-BPM-03 AR1-BPM-04 AR1-BPM-06 Plot sqrt(β) (~ beamsize) vsrms x position with the train, for each BPM trace. The β at each BPM comes from model on previous slide. There does seem to be strong correlation, perhaps expected. AR1-BPM-03 AR1-BPM-04 AR1-BPM-01 AR1-BPM-06

  9. After Twiss evaluation, restore the #3139 “AP” set up and study dispersion and R56 of AR1 AR1 Studies

  10. AR1 Dispersion Measured on AR1-BPM-06 Each plot is BPM x position vs beam energy Vary AR1-Q1/4 from 1.9 to 2.4 in 8 steps Dispersion (mm) vsAR1-Q1/4 current

  11. AR1 R56 measured on AR1-BPM-06 Each plot is BPM relative path length vs beam energy Vary AR1-Q1/4 from 1.9 to 2.4 in 8 steps R56 (mm) vsAR1-Q1/4 current AR1-Q1/4 current

  12. Summary R56 R16 AR1-Q1/4 current AR1-Q1/4 current Isochronous + zero dispersion condition at AR1-Q1/4 = 2.18 A

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