1. Muhammad F. Kasim & James Holloway University of Oxford, UK PhD Supervisors: Professor Peter Norreys & Professor Philip Burrows University of Oxford, UK AWAKE PEB Meeting, Geneva, 13 th November 2015 Spectral Interferometry for plasma wakefield diagnostics in AWAKE

2. AWAKE PEB Meeting, 13 November 2015 2 University of Oxford, RAL, UCL Photon acceleration

3. AWAKE PEB Meeting, 13 November 2015 3 University of Oxford, RAL, UCL Spectral interferometry

4. AWAKE PEB Meeting, 13 November 2015 4 University of Oxford, RAL, UCL Spectral interferometry Spectrometer

5. AWAKE PEB Meeting, 13 November 2015 5 University of Oxford, RAL, UCL Spectral interferometry

6. AWAKE PEB Meeting, 13 November 2015 6 University of Oxford, RAL, UCL Spectral interferometry Very small, so it does not disturb the plasma wakefield

7. AWAKE PEB Meeting, 13 November 2015 7 University of Oxford, RAL, UCL Spectral interferometry Expected pattern

8. AWAKE PEB Meeting, 13 November 2015 8 University of Oxford, RAL, UCL Spectral interferometry

9. AWAKE PEB Meeting, 13 November 2015 9 University of Oxford, RAL, UCL Spectral interferometry Fourier transform of every row

10. AWAKE PEB Meeting, 13 November 2015 10 University of Oxford, RAL, UCL Spectral interferometry

11. AWAKE PEB Meeting, 13 November 2015 11 University of Oxford, RAL, UCL Spectral interferometry

12. AWAKE PEB Meeting, 13 November 2015 12 University of Oxford, RAL, UCL Spectral interferometry

13. AWAKE PEB Meeting, 13 November 2015 13 University of Oxford, RAL, UCL Spectral interferometry

14. AWAKE PEB Meeting, 13 November 2015 14 University of Oxford, RAL, UCL Spectral interferometry Crop and shift to the centre

15. AWAKE PEB Meeting, 13 November 2015 15 University of Oxford, RAL, UCL Spectral interferometry

16. AWAKE PEB Meeting, 13 November 2015 16 University of Oxford, RAL, UCL Spectral interferometry Take the inverse Fourier Transform for each row

17. AWAKE PEB Meeting, 13 November 2015 17 University of Oxford, RAL, UCL Spectral interferometry

18. AWAKE PEB Meeting, 13 November 2015 18 University of Oxford, RAL, UCL Spectral interferometry

19. AWAKE PEB Meeting, 13 November 2015 19 University of Oxford, RAL, UCL Spectral interferometry

20. AWAKE PEB Meeting, 13 November 2015 20 University of Oxford, RAL, UCL Spectral interferometry

21. AWAKE PEB Meeting, 13 November 2015 21 University of Oxford, RAL, UCL Spectral interferometry

22. AWAKE PEB Meeting, 13 November 2015 22 University of Oxford, RAL, UCL Spectral interferometry

23. AWAKE PEB Meeting, 13 November 2015 23 University of Oxford, RAL, UCL Spectral interferometry

24. AWAKE PEB Meeting, 13 November 2015 24 University of Oxford, RAL, UCL Spectral interferometry

25. AWAKE PEB Meeting, 13 November 2015 25 University of Oxford, RAL, UCL Spectral interferometry

26. AWAKE PEB Meeting, 13 November 2015 26 University of Oxford, RAL, UCL Spectral interferometry

27. AWAKE PEB Meeting, 13 November 2015 27 University of Oxford, RAL, UCL First: –Take a reference shot without the plasma wakefield –Determine the chirp coefficient by varying the delay between the probe and ionising pulses (not drawn) and relating it with “phase jump” position in frequency domain Second, take the measurements using 2 pulses with the plasma wakefield Spectral interferometry summary Spectrometer

28. AWAKE PEB Meeting, 13 November 2015 28 University of Oxford, RAL, UCL To obtain the phase modulation for each shot: Need to do the steps in every shot with 2 pulses. Takes only ~ 0.3 s for one operation in MATLAB. Limited by the CCD readout time. Spectral interferometry summary F.T. row-wise Crop and shift the band Apply the I.F.T. row-wise Extract the phase

29. AWAKE PEB Meeting, 13 November 2015 29 University of Oxford, RAL, UCL THANK YOU! Image credit to: http://sf.co.ua/13/07/wallpaper-2937024.jpg

30. AWAKE PEB Meeting, 13 November 2015 30 University of Oxford, RAL, UCL APPENDIX

31. AWAKE PEB Meeting, 13 November 2015 31 University of Oxford, RAL, UCL Plasma wakefield diagnostics working region: AWAKE Working Region

32. AWAKE PEB Meeting, 13 November 2015 32 University of Oxford, RAL, UCL More accurate retrieval technique

33. AWAKE PEB Meeting, 13 November 2015 33 University of Oxford, RAL, UCL Challenges in AWAKE

34. AWAKE PEB Meeting, 13 November 2015 34 University of Oxford, RAL, UCL Transverse profile Challenges in AWAKE

35. AWAKE PEB Meeting, 13 November 2015 35 University of Oxford, RAL, UCL Transverse profile Challenges in AWAKE

36. AWAKE PEB Meeting, 13 November 2015 36 University of Oxford, RAL, UCL Transverse profile Challenges in AWAKE Modulated part here gets diffracted

37. AWAKE PEB Meeting, 13 November 2015 37 University of Oxford, RAL, UCL Transverse profile Challenges in AWAKE

38. AWAKE PEB Meeting, 13 November 2015 38 University of Oxford, RAL, UCL Transverse profile Challenges in AWAKE We can extract the unmodulated part as the reference pulse

39. AWAKE PEB Meeting, 13 November 2015 39 University of Oxford, RAL, UCL Need to transport the probe pulse from plasma column to the diagnostic table We could use 4f system Transport optics