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EO

EO. Change this summary to WHAT ACTUALLY HAPPENED RATHER THAN PARAPHRASING FROM shift summaries. 2010 data (Period 9-10) June 27 set-up shift July 2 set-up shift July 6-7 THz set-up July 18 FEL set-up 2011 data Feb 20 set-up shift Mar 14 “no result”

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EO

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  1. EO • Change this summary to WHAT ACTUALLY HAPPENED RATHER THAN PARAPHRASING FROM shift summaries. • 2010 data (Period 9-10) • June 27 set-up shift • July 2 set-up shift • July 6-7 THz set-up • July 18 FEL set-up • 2011 data • Feb 20 set-up shift • Mar 14 “no result” • Mar 16 “First EO characterisation of lasing electron beam” • Mar 21 #2361-2. HIGH RESOLUTION VERSION. “Observed EO signal and studied it as a function of beam steering, buncher charge, LC phase.”  • Mar 23 #2368 “Short time spent on EO signal studies. Good news is that it worked almost immediately with very little set-up required.”  • 19 April 2011 #2420-2421. Some brief scanning of AR1-Q1 and AR1-SEXT-1

  2. 2 July 2010, Shift #1901 • Preliminary set-up with THz set-up • Buncher power = 550 W, BC1 = -20 BC2 = +20 LC = +18 • From Log #1901. “Signal weak - only a strong signal every 5-15 shots on the scope”

  3. 6-7 July 2010 • THz set-up Buncher power = 530 W, BC1 = -20 BC2 = +20 LC = +18 (i.e. restored #1901)

  4. 6 July 2010 #1915 • \\Spj36dell\c\EOexpt\scans_6jul10 • Restored “THz” set-up from #1901 and tried to optimise EO signal using linac phase scan • “From the EO signal Steve estimates there is a ~3ps timing jitter on the beam.” • “We have done some scans changing the phase (not changing the gradient) the best EO signal is at about +17 degrees.” • 20 files containing ~ 17000 shots of the scope trace, not labelled or recorded with info as to what linac phases were. • 17000 at 10 Hz (rep rate of TW laser) == ½ hour of data ?? • Scanning the linac phase affects TOA, so to measure jitter have to know that the linac phase is not being scanned during the data.

  5. 6 July 2010 #1915 First 6 summary files all the shots look like this successive shot examples see signal appearing on left and moving to right, is this the timing scan ?

  6. 7 July 2010 #1916 • Restored BURT 1100706_223443 and restored RF settings (+18 deg from crest) from yesterday's shift (22:23) • Yesterdays shift = 6 July = THz set-up • “Returned to +18 deg linac phases for EO work. Decent energy recovery.” • “Moving laser timing to observe electron bunches at different parts of the train” Summary16.mat

  7. 21 March 2011 #2361-2 • Shift summary. “Observed EO signal and studied it as a function of beam steering, buncher charge, LC phase.” • This is a misleading summary. It means ST2-DIP-04 was steered to improve signal, buncher POWER was changed to improve signal, and LC phase was scanned at end of shift • Also AR1-sextupole-01 was varied but this isn’t mentioned in the summary. • This was the ‘Temporal Decoding’ technique (was it ‘Spectral Decoding’ in 2010) for high resolution • "FEL-03" i.e. #2349 12:19 set-up but without lasing attempted. • At end of shift quick measurents of EO signal vs • AR1 sextupoles • Linac phase • The quick measurements at end of shift low resolution version was switched to see shift note at 15:16.

  8. 21 March 2011 #2361-2 • Quality of some of the Gaussian Fits.

  9. 21 March 2011 #2361-2 • AR1-SEXT-01 (probably) at 0 and 3 A. • Tried Gaussian fits to the EO signals. mean position of EO signal sigma of EO signal blue AR1-SEXT-01 = 0 A, red AR1-SEXT-01 = 3 A

  10. 23 March #2368 • “Looked at EO signal vs AR1-SEXT-01. Seems to be most compressed bunch at sext = 4.5 A with the current BURT” • “Then changed the AR1 quads by small tweaks (0.01 A) and then found a setting where the EO signal looked better with SEXT = 0” • So not really parameter scans. • Calibration hinted at in \EOexpt\23Mar2011\AliveEOTDfig.m and AliceEOTDfig.m (plots at aliceeotdfigb.eps) • “CalibrationConst = 1/50; %estimate only - for IRUVX figure !%7.6993*1e-3;” • This looks a bit different to the only previously published EO plots EOexpt\scans_7july2010\wednesdaySummary27.mat ( was originally sent these plots from Trina by email, which indicated the filename)

  11. 19 April 2011 #2420-2421 • 1 shift setting up • Next shift attempting param scans AR1-Q1 and AR1-SX-1 done right at the end in ..Summary29-31.mat files.

  12. Questions • What does the shot from the MATLAB files mean? Single electron bunch? Or average over several bunches within train? • What do two subsequent bunches mean? Bunches from different trains? • Transverse distance from bunch to crystal. • “Background” peaks compared to main peak. • How is calibration calculated, what does 1 bin on the 1280 bin histrogram mean, i.e. can you really resolve bunch features on a 1/1280 resolution? • Was ‘spectral decoding’ or ‘temporal decoding’ EO techniques used ?

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