2395 bare ramp 26 3 2011 bare ramp

2395 – bare ramp 26 -3 -2011 bare ramp

26 -3 -2011 bare ramp

Q’ 26 -3 -2011 bare ramp

tune 26 -3 -2011 bare ramp

26 -3 -2011 bare ramp

26 -3 -2011 bare ramp

Snapback – Q’ n Fit snapback: n I(t) – MB current at time t Iinjection – injection value of current b 3 and I are fitting constants n n n b 3 and I are correlated Sextupole compensation during snap-back in collaboration with FNAL – Luca Bottura 26 -3 -2011 bare ramp

Faster snapback 26 -3 -2011 bare ramp

Naked versus correction 26 -3 -2011 bare ramp

1545 Tune modulation up ramp 26 -3 -2011 bare ramp

Tune 1545 26 -3 -2011 bare ramp

Tune correction 1545 Tune feedback on – some small correction of modulation 26 -3 -2011 bare ramp

1580: QPH correction 26 -3 -2011 bare ramp

1580: QPV correction 26 -3 -2011 bare ramp

Naked versus correction 26 -3 -2011 bare ramp

1584 – no tune feedback 26 -3 -2011 bare ramp

Observations n n Tunes and chromaticities more-or-less identical for both beams Watch carefully de-convolution of tune correction of tune modulation given by RF frequency modulation ¨ n b 3 snapback correction 50% of total swing ¨ n Approx total swing: H -34. 8 V 25. 42 Snapback time constant looks more or less OK ¨ 26 -3 -2011 Pseudo spikes at start of ramp; offset in estimate Most of it’s over after around 21 seconds bare ramp