1. 1Ben Constance7 th January 2010 FONT5 December 2009 feedback results During the final shift we ran K1-to-P2 position feedback 151.2ns bunch spacing, quadrupoles on 5 gain settings with charge normalisation (2000 – 2400) 8 ZV6X settings at each gain to generate t-shirt data (~250 micron range in P2) Some gain settings taken with interleaved feedback on/off To save time, some settings were only FB on with occasional FB off runs taken Additionally, throughout: Calibration constant of 0.0022 used Low bunch charge cut by threshold Fliers removed at 3 sigma All averages over ~50 pulses per point

2. 2Ben Constance7 th January 2010 Baseline subtraction effects The firmware does NOT subtract baseline when forming feedback signal The true position y 0 is: While feedback sees: With calibration constant of 0.0022: Σ 0 ~ 300 ∆ b ~Σ b ~ 30 Charge - dependent

3. 3Ben Constance7 th January 2010 Gain setting Gain set to converge on y FB = 0 Decided in FONT meeting to add GUI switch to disable base subtraction in plots Previous shift data suggested gain ~2200 to give y FB = 0 In real terms, feedback converges on - ∆ b / (Σ 0 + Σ b ) [few micron variation] Dotted line shows the average position to which the feedback should converge To avoid confusion, all following plots are analysed with baseline subtraction, i.e. they correspond the true position Analysed with baseline subtraction Analysed without baseline subtraction

4. 4Ben Constance7 th January 2010 T-shirt plots Following 8 slides show t-shirt plots for gain -2100 Gain -2100 gave best results Each point averaged over ~50 pulses Error bars show the RMS jitter Data are interleaved feedback on/off

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12. 12Ben Constance7 th January 2010 Kicker probably saturating

13. 13Ben Constance7 th January 2010 Gain comparison Overlaid T-shirt plots Data with feedback on at each corrector setting are overlaid on the next 5 slides One plot for each gain setting Staircase plots The final 5 slides show the equivalent staircase plots in P2

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