Top-up Operation - Preservation of Bunch Pattern SPring-8 12/03/02 - PowerPoint PPT Presentation

“Top-up” Operation at the Swiss Light Source Top-up Operation - Preservation of Bunch Pattern SPring-8 12/03/02 Michael B¨ oge 31

“Top-up” Operation at the Swiss Light Source Top-up Operation - Injection Oscillations BPM in single turn mode: 600 500 Horizontal Plane: 400 300 +300 µ m • 800 µ m peak-peak over 6 µ s 200 coherent decoherent amplitude [ µ m] 100 0 • Decoherence time ≈ 600 µ s -100 -200 Vertical Plane: -300 -400 −500 µ m 1.2 msec -500 x • Excitation < 15 µ m BPM noise y -600 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 time [msec] injection 0.012 x y 0.01 power spectrum [ µ m/ √ Hz] 0.008 0.006 ν x =0.42 ν y =0.17 0.004 0.002 0 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 fractional tune SPring-8 12/03/02 Michael B¨ oge 32

“Top-up” Operation at the Swiss Light Source Top-up Operation - Losses @ U24 10 7.450 mm 7.288 mm coincidence count rate [10^4 Hz], gap [mm], current [A] coincidence count rate Scintillator count rates @ ID U24 – > 7.847 mm gap 9 current I heard that you do not use the sys- 300 injections 8 tem of gate-signal delivery to experi- 7 45/6=7.5 mental users during top-up injections. 6 37/5=7.4 25/4.5=5.6 We would like to know how experimental 5 users know (or don’t care about) the tim- 4 ing of series of injections, and also how 3 to exclude its negative contamination to 2 their experimental data due to possible 1 fluctuation of X-ray beam. 0 0 1 2 3 4 5 6 7 8 9 10 We don’t do anything ... We plan to time [h] do a fast (ms resolution) measurement of injection every 2.3 min @ 10h lifetime the beam intensity during injection to get a fealing for the distortions. (C. Schulze-Briese, PX beamline re- 5s sponsible) 20/4.3 SPring-8 12/03/02 Michael B¨ oge 33

“Top-up” Operation at the Swiss Light Source Top-up Operation - Losses @ U24 ... May be you even have some plots which illustrate the positive and negative influences of Top-up operation on your various experimental setups. We don’t have plots but it can be said that the effect of Top-up on the data quality is rather positive than negative . It is believed that a small and periodic distortion is better than a continuous drift / change during the data collection. We are able to measure at least as good quality data as ESRF and a particular difficult case that was not solvable at ESRF was solved here during Top-up operation. Some users told me that in SLS so far there is no experiment which requires very sever beam stability. I doubt this opinion. So please make clear what kind of experiment performed in SLS. There I ask you to explicitly clarify the requirement of each experiment to beam quality. The beam stability of < 1 µ m rms and < 1 µ rad rms is more than sufficient for Protein Crystallography. Another nice aspect of SLS is the reproducibility of the beam position after shutdown. Typically the beam comes back to few microns and the intensity is the same as before. (C. Schulze-Briese, PX beamline responsible) SPring-8 12/03/02 Michael B¨ oge 34

“Top-up” Operation at the Swiss Light Source Top-up Operation - Temperature and Pressure 100 deg C = Maximum Temperature Temperature 12 * 6 = 48 sensors 26 deg C Pressure 1e−7 = Maximum Pressure 34 gauges arc flange 3HC injection 4.5e−8 mbar 4e−8 mbar 2e−8 mbar SPring-8 12/03/02 Michael B¨ oge 35

“Top-up” Operation at the Swiss Light Source Top-up Operation - Gap Control and Interlocks Gap Control: • Set Operator/Experiment • Status Orbit Autodump Params Gap Control Kicker/Septum Control: • Set Disarm/Rearm • Status Orbit Autodump: • Set Parameters Kicker/Septum Control • Status Orbit Sources Autodump Sources Autodump: Temp • Orbit RF • Temperature • RF 3HC • 3HC SPring-8 12/03/02 Michael B¨ oge 36

“Top-up” Operation at the Swiss Light Source Top-up Operation - Controls SR Current Bunch Charge Tuneshifts Chromaticities Gap Control Nominal Tunes & Orbit Autodump Params Chromaticities Bunch Pattern Sources Autodump Orbit Temp RF Top−up Control 300−301 mA 3HC Gun Trigger Kicker/Septum Control SPring-8 12/03/02 Michael B¨ oge 37

“Top-up” Operation at the Swiss Light Source Top-up Operation - Beam Time and Faults SPring-8 12/03/02 Michael B¨ oge 38

“Top-up” Operation at the Swiss Light Source Top-up Operation - Accumulated Beam Dose 1200.0 1150 Ah 1000.0 800.0 Accumulated Beam Dose [Ah] 900 Ah 600.0 400.0 250 Ah 200.0 2002 0.0 Aug.2001 Apr.2002 Jun.2002 Aug.2002 Oct.2001 Dec.2001 Feb.2002 Oct.2002 Dec.2002 SPring-8 12/03/02 Michael B¨ oge 39

“Top-up” Operation at the Swiss Light Source Slow Orbit Feedback - Golden Orbit 0.5mm horizontal difference orbit 72 BPMs 72 corrs /plane −0.5mm ~1 µ m ν x =20.42 0.5 Hz (3 Hz) refreshrate ~0.3 µ m vertical difference orbit precision of BPMs golden orbit bba offsets ~1 µ m ν y =8.17 SPring-8 12/03/02 Michael B¨ oge 40