1/33Mikey Davis24 January 2013 Review of 23 rd of January Shift

2/33Mikey Davis24 January 2013 Introduction Will go through what we did on shift Review analysis of data and some results Discuss things that went wrong and problems Review plan for next shift

3/33Mikey Davis24 January 2013 Setup The setup hasn’t changed much from October Upstream – The RCPS are attached to P2 and P3 for best FB – There are options for either P1 or MQF15X – 6 dB on all BPMs Downstream – Variable attenuation on Y only (X used by ATF) – A and B on same control (can only be set together) – 40 dB flat on X – 30 dB on reference cavity + 20 dB on FONT 5 board

4/33Mikey Davis24 January 2013 Setup Kicker setup – The kicker setup from October has been repeated – Switching in the Eels bedroom controls the trigger which is sent to IPK or K2 – DACOUT 2 is amplified then split, using 6 dB splitter – Half goes to K2 and the other half -> FF cable – Both setups have been tested FF setup shows “correct” response – for first time Upstream seems a bit noisy but nothing unusual Upstream tested and visually kicking the beam

5/33Mikey Davis24 January 2013 Setup Courtesy of Neven

6/33Mikey Davis24 January 2013 Summary of Shift We were lucky to be offered a double shift through lack of user interest I therefore arrived around 4 am to begin the setup The shift fell naturally into three parts separated by prolonged accesses – Setup of the DAQ initial testing of RCPS – Access – Final setup of DAQ and RCPS, initial cavity tests – Access – Machine broke, analysis of data and wait

7/33Mikey Davis24 January 2013 First Part Unfortunately due to the lack of good quality beam in the extraction line (or in fact any beam) I was unable to setup the RCPS before the shift When I arrived at 4 the beam was highly unstable however this was fixed so DAQ was setup then with Neven began RCPS calibration Done successfully but P2 fell outside allowable range

8/33Mikey Davis24 January 2013 RCPS Results

9/33Mikey Davis24 January 2013 First Access - 6 am Because the RCPS was outside allowable range we decided to take an access to make an adjustment We also needed to make some changes to the IPBPM setup – Although we agreed to change the attenuation it was decided prudent to leave setup as is – I thought this left the X IPA and IPB on one control and Y IPA and IPB on another – This turned out to be incorrect and only Y could be controlled – This left only fixed 20 dB on X

10/33Mikey Davis24 January 2013 First Access The reference cavity signal was also large although appeared not to be saturating We therefore decided to – Increase the X atten. to be 40 dB as agreed – Increase ref atten. to 30 dB We also found 20 dB fixed on IPA left from October This was removed to leave: IPAIPBRef X40 dB N/A Yvariable attenuator30 dB

11/33Mikey Davis24 January 2013 First Access Recovery Unfortunately when recovered beam was unstable We waited until 8 am when stable beam was recovered On a sub note we were still using P1 at this point There were concerns we hadn’t actually asked Glen White to use it Neven ed him

12/33Mikey Davis24 January 2013 RCPS Setup

13/33Mikey Davis24 January 2013 RCPS Setup

14/33Mikey Davis24 January 2013 RCPS Setup P2 not ideal but we wanted to continue 1μ / ° corresponds to jitter of roughly 0.3μ A quick jitter run (500 pulses) gave estimated of res: Res (μm)P1P2P3 Fitting Method – no LO correction Fitting Method – with LO Correction Geometric Method – no LO correction2.0 Geometric Method – with LO correction0.63

15/33Mikey Davis24 January 2013 Mover Scans Courtesy of Neven

16/33Mikey Davis24 January 2013 IPBPM Calib We then moved on to the setup of the cavity BPMs We first tried to centre the beam using EPICs – We used two magnets QD0FF and QF7FF – We tried to use a more systematic approach – Very course scans were taken and trends in each BPM noted – We found it difficult to centre the beam in both BPMs X ironically was centred easily to -10μm in IPA and 40 in IPBμm Y more difficult, we managed -80μm in IPA and 80μm in IPB – I think we could manage in Y but would take more time

17/33Mikey Davis24 January 2013 IPBPM Calib Calibrations were then taken with the waist at the nominal IP We had several problems: – As the beam was at ±80μm we were close to saturation – Calibration code didn’t work – Tried to use the bumpScan which uses the flight sim – This ignored that current position and always scanned same range, it also zeroed the mover in X – Went back to magScan which just moves QD0FF – I prefer this method as it’s easier to understand

18/33Mikey Davis24 January 2013 IPBPM Calib Finally we noticed that there is a very large offset between EPICs and HONDA This offset is > 100μm This is important to take into account

19/33Mikey Davis24 January 2013 IP Waist Scan Carried on with shift plan so next step was an IP waist scan using EPICs We obviously recorded using HONDA as well Two scans were taken with QD0FF – One coarse scan from 130A to 160A in steps of 5A – One fine scan from 125A to 139A in steps of 2A BPM was centred at waist of: – IPA at 142A – IPB at 133A

20/33Mikey Davis24 January 2013 IP Waist Scan

21/33Mikey Davis24 January 2013 IP BPM Calibration We then moved onto IP BPM Calibrations with the waist centred at each BPM The process was as follows: – Centre waist at BPM – Centre the beam at the BPM using HONDA This was done due to the large offset between EPICS and HONDA It is actually quite easy to roughly centre the beam using the FONT DAQ screen, you just look at then the signals are small

22/33Mikey Davis24 January 2013 IP BPM Calibration

23/33Mikey Davis24 January 2013 IP BPM Calibration

24/33Mikey Davis24 January 2013 IP BPM Calibration

25/33Mikey Davis24 January 2013 IP BPM Calibration

26/33Mikey Davis24 January 2013 IP BPM Calibration

27/33Mikey Davis24 January 2013 Calibration Constants It seems from the graphs that there is an extra 20dB of attenuation somewhere in the IPB region This seems to be confirmed by the calibration constants Calib Const.IPAIPB IPA Calib 1 (30dB)-50- IPB Calib 2 (30dB)-417 IPB Calib 3 (10dB)-45

28/33Mikey Davis24 January 2013 Second Access The most obvious cause of this problem seemed to be human error in setup We therefore took an access to manually check We could not find any evidence of extra attenuation Beam could then not be recovered because the linac broke

29/33Mikey Davis24 January 2013 Second Access We used this prolonged access Tested the variable attenuators using 357 and power meter – This exonerated variable attenuator Did a thorough visual inspection of entire setup – Again no evidence of an extra 20dB

30/33Mikey Davis24 January 2013 Extra 20dB I am convinced that this extra 20dB must be a problem before the first stage downmixer My reasoning is as follows: – With 10dB atten we know we will saturate the first stage at approx 13μm – A calibration was done at a atten setting of 10dB over a range of 250μm – the calibration was fine – We know this range is correct from both EPICs and the expected optics

31/33Mikey Davis24 January 2013 Extra 20dB Taking this into account we have added 20dB of attenuation to IPA This means that we can run at 30dB for both BPMs We could take this out, thoughts?

32/33Mikey Davis24 January 2013 Final IP Waist Scan Result

33/33Mikey Davis24 January 2013 Final IP Waist Scan Result

34/33Mikey Davis24 January 2013 Tomorrows Shift The Laserwire group are on double shift now They are having problems as their laser won’t work Teranuma san used the time to test 2 bunch mode – This seems to be working well He has also said that now the modulator is fixed the beam seems a lot more stable I would suggest we continue with the same plan from last shift, I think it will be quicker this time as we learnt a lot from it Neven has also done another RCPS scan in the mean time to hopefully get a smaller phase sensitivity for P2