Roundup of Week at ATF Mikey Davis 19 April 2013 1/26

Introduction I will give an overview of what happened on the shifts this week and the implications this has Will also give a roundup of the results from yesterday I’m going to try and cover everything so won’t go into anything (including the BPM waveforms etc) in great detail I’m also presenting what I think has happened, I’m not sure everyone will agree Mikey Davis 19 April 2013 2/26

What Happened Started off the shift with tests using an oscilloscope Found that the BPMs are also noisy with the scope Signals were taken with the output of the second stage split One input to the FONT V board The other input to the scope Mikey Davis 19 April 2013 3/26

Scope Test Mikey Davis 19 April 2013 4/26

Scope Test Mikey Davis 19 April 2013 5/26

Scope Test Mikey Davis 19 April 2013 6/26

What Happened We then setup to take data using both the FONT board and the SIS digitiser Decided as we only had 2 channels on the SIS digitiser we should undo BPM signal split and connect both BPMs We then continued with the normal program We decided to centre the beam at IPA due to the ripples at IPB I noticed that the orbit wasn’t flat through the IP so tried to correct this Mikey Davis 19 April 2013 7/26

What Happened The method for flattening the orbit involves QD0FF and QF7FF First centre beam in the BPM where the waist is using QD0FF Then use QF7FF to rotate the beam around the IP Whilst doing this I noticed that the beam moved a lot at IPA but not at all in IPB (in the Honda system) I then realised the jitter was also much larger at IPA then at IPB (in the Honda system) Mikey Davis 19 April 2013 8/26

What Happened We then looked at direct comparison with the EPICs system and Honda system In the EPICs system the beam waist was clearly at IPA, QD0FF magnet strength was also 145A The Honda system however seemed to give the opposite impression We took an access and checked everything was setup correctly in the tunnel and out of it It was, which suggests that what the cable we think gives us IPA is in fact IPB Mikey Davis 19 April 2013 9/26

Summary In EPICs as we record it, and on the control system IPA and IPB are the correct way round In our system, certainly this trip and I think in March IPA and IPB have been back to front Neven and I have evidence to suggest that they were correct in January Our system is setup as we think, and was setup as we thought in March The BPM labels must be back to front Mikey Davis 19 April 2013 10/26

Implications We have now spent considerable time measuring the jitter at the “waist” BPM and getting a number of 4 microns or higher We’ve then put this down to resolution Last night showed us that the real jitter at the non waist BPM is 4 microns We have been measuring the true jitter at that BPM This trip only using one BPM has not helped this This helps make sense of some erroneous results EPICs and Honda no longer have a 60 micron offset Mikey Davis 19 April 2013 11/26

March IPB Waist Scan Mikey Davis 19 April 2013 12/26

March IPB Waist Scan Mikey Davis 19 April 2013 13/26

IPB Waist Scan Last Night Mikey Davis 19 April 2013 14/26

Summary of Jitters Attenuation Setting (dB) IPA Jitter (μm) IPB Jitter (μm) 20 4 1.1 10 3.8 0.4 Calibration not done 0.25 Mikey Davis 19 April 2013 15/26

Two Bunch Mode We decided to capitalise on the BPMs working and switch to two bunch mode Wanted to see if the results were the same Also wanted to look at the correlations Mikey Davis 19 April 2013 16/26

Summary of Correlations Bunch to Bunch Correlations Attenuation Setting (dB) P2 b2b Correlation (%) P3 b2b Correlation (%) IPA b2b Correlation (%) IPB b2b Correlation (%) 10 94 92 45 95 Calibration not done 79 Upstream Downstream First Bunch Correlations Attenuation Setting (dB) P2 IPA Correlation (%) P3 IPA Correlation (%) P2 IPB Correlation (%) P3 IPB Correlation (%) 10 68 57 4 5 Calibration not done 25 24 For this run you get the same even if you’re looking at first bunch to second bunch correlations Mikey Davis 19 April 2013 17/26

Feedback Runs We see a good improvement at IPA, nothing at IPB 3 runs done at 10 dB, 1 run done at 0 dB Mikey Davis 19 April 2013 18/26

FB Run 1 – 10 dB Mikey Davis 19 April 2013 19/26

FB Run 2 – 10 dB Mikey Davis 19 April 2013 20/26

FB Run 3 – 10 dB Mikey Davis 19 April 2013 21/26

FB Run 4 – 0 dB Mikey Davis 19 April 2013 22/26

Feedforward Runs IPK appears to be working fine Only one valid run, others we were just kicking 4000 counts in one direction every time We make it worse for this run Still kicking the beam a long way away from zero We guessed at the calibration constants At 0 dB so expect nothing from IPA Mikey Davis 19 April 2013 23/26

IPK Scan Mikey Davis 19 April 2013 24/26

FF Run 3 – 0 dB Mikey Davis 19 April 2013 25/26

FF Run 1 – 0 dB Mikey Davis 19 April 2013 26/26