Snapback Analysis - Updates

Tune and chromaticity decay during injection-comparing 2010 and 2011Nicholas AquilinaTE-MSC-MDA

Acknowledgements:E. Todesco, W. Venturini Delsolaro, EIC and operatorsCERN, FiDeL meeting, 8th March 2011 ContentsComparing the result from the measurements of:September to October 2010The first few weeks of operation of 2011

03/08/20112Fitting of the dataA double exponential1 of this form was used to model this decay03/08/20113This model fits very well the tune and chromaticity decay1 N. Sammut, L. Bottura, and J.Micallef. Phys. Rev. ST Accel. Beams 9, 012402 (2006)

Tune measurements and their fits03/08/201111/02/21 (01)4

11/02/24 (08)11/03/01 (17)11/02/25 (16) (collimator setup)All the tune fits03/08/2011 5

3 groups of curves: a) first 3 injection (starting at 0.295) b) injection preceded by another injection (starting 0.31) c) injection preceded by ramp (starting 0.305)Tune decay 2010 vs 2011Tune decay amplitude is less than what was observed during last year (70% of 2010)Tune decay is also slower03/08/20116

20102011parameterhorizverthorizvertc0.0320.0300.0240.022d0.280.210.330.322000200040004000v0.3080.2420.3050.232Chromaticity measurements and fits11/02/21 (01) (first measurement)03/08/2011711/02/23 (04)11/02/25 (16) (collimator setup)11/03/01 (08)

All the chromaticity fits03/08/20118

First two measurements behave differently than the othersIn some cases the data is available for the first 4000 seconds only!!

Chromaticity decay 2010 vs 201103/08/20119

20102011QhQvaverage Qaverage b3QhQvaverage Qaverage b3c' -231820.50.51-221518.50.461d'0.100.100.100.100.430.460.450.45'10001000100010001000100010001000-89-55n/an/a-90-52n/an/a1 taking 1 unit of b3 = 40 units of Q

Chromaticity decay amplitude is almost the same as last year.ConclusionTune decay amplitude during 2011 is 70% of the tune decay amplitude observed during September October 2010The tune decay observed in 2011 is 2 times slower than that in 2010Chromaticity behaviour in 2011 is very similar to that in 2010

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