1. The ORS at FLASH and sFLASH Peter van der Meulen Stockholm University Div. Molecular Physics FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources a new diagnostic tool for characterizing electron bunches

2. ORS: Optical Replica Synthesizer FLASH, XFEL, JFEL, LCLS: SASE electron bunch properties: longitudinal density profile slice emittance slice energy spread SASE is very sensitive to the properties of the electron bunch need to control and measure these properties! electron bunch: moving at v ≈ c ca. 20  m long ca. 100  m wide hard to measure directly  measure an optical copy instead FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

3. ORS: Optical Replica Synthesizer FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

4. ORS: Optical Replica Synthesizer Erbium fiber oscillator: 1550 nm ca. 54 MHz amplified frequency doubled, 1 mm PPLN 1 – 5 mW Clark-MXR CPA2001 Ti:Sapph CPA system 5 Hz (1 kHz) ca. 700  J/pulse 0.2 – 3.0 ps FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

5. ORS: temporal overlap Er:fiber oscillator stretchercompressor Ti:Sapph amplifier to tunnel ca.54 MHz pulse train FLASH 5 Hz trigger ca.19 ns Fourier Transform24 th harmonic ca. 1.3 GHz diff. freq. mixing FLASH RF 1.3 GHz vector modulator Matlab progam piezo + delay  …+ cos[( .t +  ] = 0 delay FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

6. ORS: Magnet structures Undulators: electromagnets 1450 mm 40 mm gap, 0.5 T max. 14 poles (1/4,-3/4,1,-1…) 4 power supplies modulator vertical radiator horizontal Chicanes: 4 dipole magnets 1300 mm FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

7. ORS: spatial overlap calibration and OTR screens on 7Match and 3SUND1 Joern Boedewadt FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

8. ORS: temporal overlap Coherent OTR @ 385 nm PRSTAB 11, 070702, 2008 FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

9. GRENOUILLE * based on SH FROG technique (autocorrelator + spectrometer) single shot measurement 2D phase retrieval algorithm => fully characterized pulse Electric field profile  electron bunch profile (  I 4 ) femtosecond optical pulse characterization * Swamp Optics FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

10. ORS: FROG trace seed laser pulse: ca. 400 fs FWHM FROG trace: ca. 150 fs FWHM  FLASH’s electron bunch spike? Compatible with SASE!!! FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

11. ORS: FROG trace ca. 1-5  J/pulse ca. 150 fs FWHM no direct comparison with TDC (LOLA)  FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

12. ORS at FLASH Some remaining issues: cross check with TDC (LOLA) and/or EO measurement laser power: 1 mJ/ pulse  30 mJ/pulse better digital data collection: 8 bit  12/16 bit what happens under further bunch compression? CSR? what is the future of the ORS? The ORS seems to work, but… FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

13. ORS: FROG trace A FROG trace obtained upon further compressing the electron bunch: FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

14. ORS at sFLASH temporary shutdown September 2009 rebuild ORS in new position FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

15. ORS at FLASH Other applications of the ORS: phase of optical replica pulse  energy chirp of electron bunch slice energy spread slice emittance 3D spatial electron bunch characterization via coherent OTR ‘echo’ test experiments (G. Stupakov, SLAC-PUB-13445, Oct. 2008) ORFIR general study laser – electron interactions FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

16. conclusions first ORS results obtained in 2009!!! the ORS seems a very useful addition to (s)FLASH, as a diagnostic device. Some issues deserve further study. more (parasitic) beam time is required to make the ORS a standard and routine diagnostic technique. ‘alternative’ applications of the ORS appear very promising. FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

17. DESY, 27 January 2009 Collaborators Stockholm University: Peter Salen Mathias Hamberg Mats Larsson Uppsala University: Volker Ziemann Gergana Angelova-Hamberg DESY: Holger Schlarb Florian Löhl Hamburg University: Joern Boedewadt Axel Winter Shaukat Khan BESSY: Atoosa Meseck DESY: E. Saldin, E. Schneidmiller & M. Yurkov FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

18. THANK YOU! FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

19. ORS: temporal overlap Holger Schlarb Florian Löhl FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

20. ORS @ sFLASH What to do: move undulators, dipoles and optical stations (+ cables) re-build OS1 chicane in vertical plane; re-design OS2 chicane change to HHG laser; 10% beamsplitter, ca. 4 mJ/pulse + compression improve laser beam diagnostics insert new OTR screens:  diffuse scattering screen  doped YAG screen for e-beam and laser?  better optical quality: surface and flatness FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

21. DESY, 27 January 2009 BOA pulse compressor Bother-free Optimized Arrangement Swamp Optics fused silica transmission grating, ca. 1000 l/mm no angular dispersion no pulse front tilt no spatial chirp FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

22. imaging using coherent OTR/ODR: longitudinal bunch profile  high k – small wavelength compared to THz measurements  high intensity I(r)  N  d 2 r’ dz  (r’,z)  E one-electr (r-r’)  2 + N 2  d 2 r’ dz exp(-ikz)  (r’,z) E one-electr (r-r’)  2 I coh (r)  N 2  d 2   ( ,k) (  exp(i  r))/(  2 +  2 )  2  = k/  if  ( ,k) = f(  ). g(k)  X but…. ORS contributions to sFLASH FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources

23. The ORS as a routine diagnostic? PRSTAB 11, 070702, 2008 what about the possibility to do an image reconstruction using algorithms similar to those applied in single-particle X-ray diffraction? multiple k’s and modulation using chirped seed pulses FLS2010, March 1-5, 2010, 48 th ICFA Advanced Beam Dynamics Workshop on Future Light Sources