2. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Esperimenti con fasci di elettroni brillanti per la fase 2 di SPARC High Brightness e - Beams & TW Power Photon Beams : Applications for SPARC-II Velocity Bunching (CORA) : production of ultra-short bunches Ultra-High Gradient Acceleration : a 2nd generation Plasma Acceleration experiment A Source of Mono-chromatic X-Rays for advanced clinical diagnostics Luca Serafini - INFN / Milano

3. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Transverse Brightness of Electron Beams Quality Factor : beam peak current density normalized to the rms beam divergence angle (linked to transverse beam coherence) I = peak current  nx = rms normalized transverse emittance z   Round Beam :  nx =  ny, J = I /  2   ’  x x’  eq  ’ high  ’ low

4. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Brightness is crucial for many Applications SASE FEL’s Plasma Accelerators Relativistic Thomson Monochromatic X-Ray Sources Courtesy of D. Umstadter, Univ. of Michigan

5. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Three Generations of Electron Sources Thermo-Ionic time-scale Q bunch =1-100 nC B n =10 10 A/(m. rad) 2  s  ns (ps with RF bunchers) I=0.1  10 A DC Diode (triode) with thermoionic cathode E ≈10 MV/m Photo-Injectors time-scale Q bunch =0.1-10 nC B n =10 15 A/(m. rad) 2 ps I=10  100 A RF Cavity with photo-cathode E ≈50-150 MV/m Plasma Guns time-scale Q bunch =1-10 pC B n =10 14 -10 15 A/(m. rad) 2 fs I≈ 1 kA Langmuir waves in cold plasmas + local wave-breaking E ≈ 1-10 GV/m

6. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Achieved Brightness in RF Photo-Injectors TTF photo-inj. (achieved)6. 10 12 exit of linac (compr.)2. 10 13 ATF photo-inj. (achieved)5. 10 13 @ photocathode 1.2. 10 15 Max. achievable without compr.  n-cath =  thermal LCLS (requested @ 15 GeV) 4. 10 15  nx =  ny =1.5  m SPARC ultimate goal (Ph. 2) 2. 10 15 ESRF (storage ring) < 10 14  nx =20  m  ny =0.07  m I = bunch peak current

7. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Web page: www.physics.ucla.edu/AABD THE PHYSICS OF HIGH BRIGHTNESS BEAMS Proc. of the 2nd ICFA Advanced Accelerator Workshop University of California, Los Angeles, Nov. 1999 edited by James Rosenzweig & Luca Serafini Wide International Community on High Brightness Beams Physics and Science with the X-ray Free-Electron Laser (Arcidosso, Italy, September 10-15, 2000) C. Pellegrini and M. Cornacchia

8. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Slow wave structure Standard v=c structure Compression during acceleration Velocity Bunching: integrated compression in photoinjectors Current scaling with energy I/  = const. Courtesy of D. Yeremian, SLAC

9. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Trapped trajectories in a slow wave: the Hamiltonian model @  ≈ 1 If the phase velocity of the wave is ~c

10. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” A quarter synchrotron oscillation gives phase compression By Injecting at and extracting at we perform an energy spread enhancement associated to a phase spread reduction rf wave Beam run off-crest ‘chirps’ and compresses Courtesy of S. Anderson

11. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” LCLS Photoinjector with RF Compression 3 solenoids for additional focusing 2 solenoids for additional focusing

12. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” C. Ronsivalle First PARMELA Simulation of RF Compressor

13. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ”

14. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” dump 75 MeV 5 MeV dump undulators linac linac (off) 75 MeV DUVFEL RF Compression at DUVFEL P. Piot et al., PRSTAB 6 (2003) 033503

15. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Initial Velocity Compression Measurements at Livermore/Pleiades Courtesy of S. Anderson / LLNL

16. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Preliminary Results Consistent with Simulation 7º FWHM Courtesy of S. Anderson / LLNL

17. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” SPARC - Phase 2 RF-Gun X band structure RF compressorSLAC structure Longitudinal emittance compensation via 4th harmonic decelerating section (B. Spataro)

18. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Performances @ full compression  T

19. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Performances @ full compression zz  nn rr 

20. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Application to SPARX (M. Ferrario)

21. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” SPARC Building Complex Bunker open for implementation of future beam experiments with additional beam lines

22. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” SPARC-I Laser layout 10 nJ 10 ps flat-top 800 nm IR 266 nm UV Larger Laser Pulse Energy needed for TW Photon Beams

23. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Upgrade of SPARC Laser to TW Power Level: third stage of amplification to reach 0.5-1 J energy per pulse ( P > 10 TW ) Courtesy of F. Sakai

24. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Courtesy of F. Sakai Pulse Compressor under vacuum Regenerative Amplifier Multi-Pass Amplifier Pulse Stretcher Oscillator

25. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Two additional beam lines at SPARC for plasma acceleration and monochromatic X-ray beams 100 fs synchr. Ti:Sa multi-TW Laser System 1 J, 10 ps gaus 1 J, 100 fs gaus Compr. 20 mJ, 10 ps flat top 500  J 20 pC, 20 fs $ 2 nC, 10 ps* *  n =2  m,  =50  m $  n =0.2  m,  =10  m 1 nC, 10 ps,  n =1  m

26. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” All Optical Injectors (Plasma Guns) vs External Injection L.I.L.AC scheme, D. Umstadter Local Wave-Breaking induced by second (synchronized!) laser pulse Captures background plasma electrons locally into the accelerating bucket (D. Giulietti) Plasma wavelength 10-100  m External Injection in SPARC HOMDYN (M.Ferrario) p = 300  m  p = 100  m E acc = 3 GV/m T fin = 360 MeV 20 fs, 1 kA, 6% en. spread

27. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Compact Sources of Monochromatic X-rays based on Relativistic Thomson back-scattering X  las / 4  2 ((1-cos  )/2) las = 0.8  m  =80 (40 MeV) X =0.32 Å, 37 keV

28. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Dynamic IVCAG (Intravenous Coronary Arteriography) using monochromatic X-rays produced by Synchrotron Radiation and monochromators was clinically tested at KEK-AR and Tsukuba University, obtaining clear dynamic images (33 shots/s) of the coronary artery, with 37 keV X-rays, 10 11 photons/s generated by an undulator at the AR ring (intravenous contrast agent applied). Non-invasive Coronaric Angiography

29. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Mammography with Mono-chromatic X-Rays

30. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Experiments world-wide on Compton- Backscattering for Monochromantic X-rays Sumitomo-Festa (S-band, medical) Univ. of Tokyo - NERL (S-band, medical) NIRS - Univ. of Tokyo - KEK (X-band, medical) SLAC (X-band, medical) Brookhaven ATF (S-band, by-product in laser acceleration) Livermore (S-band, material studies, nuclear weapons)

31. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” 70mm (B) Measured spatial profile of the scattered X-rays Y X **The lines represent the results of the theoretic analysis** (The electron beam is in the plane of the laser polarization) Sumitomo - Festa Collab. (Tokyo)

32. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Spectral Distributions

33. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” CONCLUSIONS SPARC is aimed at delivering within 3 years a top brightness electron beam (Ph. 1) Velocity Bunching will ultimately allow to reach unprecedented quality beams in a compact system (200 MeV) SPARC has the chance to become an advanced facility in the international scenario to conduct frontier beam physics (High Gradient Acceleration and Advanced X-ray Beams)

34. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ”

35. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Innovative Concepts / Components in SPARC Use of Shaped Laser Pulses (minimize space charge non-linearities) Implementation of Ferrario Working Point in an optimized integrated photo- injector (proper phase tuning of emittance oscillations) Applying Velocity Bunching with Emittance Preservation (increasing peak current at no expense of transverse emittance)

36. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” NEW CONCEPTS Velocity Bunching in Photoinjectors RF Compression during Acceleration Rectilinear Compression (no Coherent Synch. Radiation effects) based on longitudinal focusing in slow RF waves Alternative option of bunch compression  high brightness sub-ps beams (as needed by X-Ray SASE Fel’s) Performed at low energy (10-80 MeV), fully integrated into the emittance correction process (for maximum brightness) LS and M. Ferrario, AIP 581 (2001) 87

37. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” From Thermoionic Injectors to Laser-Driven RF Photo-Injectors : the Quest for Beam Brightness Thermoionic Injectors operate in a quasi-steady state regime at low DC field amplitudes - the beam has to be manipulated by bunchers to get down to the ps time scale - this causes a severe emittance grow   Integration of emission process into the bunching action of RF accelerating field  RF Photo-Injectors Hera

38. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Emittance and brightness scaling Q [nC] 0.20.40.60.811.2 Q [nC] 0.2 0.4 0.6 0.8 1 0.20.40.60.811.2 0 200 400 600 800 1000 1200 1400 mm.mrad A/mm 2 mrad 2 S-band L-band S-band L-band X-band nn nn

39. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Temporal distributions of shaped UV laser pulses by a X-ray streak camera Gaussian pulse shape Square pulse shape The flatness of square-shaped laser pulse: The flatness of square-shaped laser pulse: 5~25% @ 4~14 ps FWHM 5~25% @ 4~14 ps FWHM The fluctuation of shaped pulse length: The fluctuation of shaped pulse length: 7% (pulse-to-pulse)@both shapes 7% (pulse-to-pulse)@both shapes Achieving Uniform Bunch Distributions using Flat-Top Laser Pulses @ Sumitomo SHI + FESTA Courtesy of F. Sakai

40. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Laser pulse length: 9ps FWHM Emittance measurements for gaussian and square laser pulse shapes Courtesy of F. Sakai Achieving Record Emittances @ Sumitomo SHI + FESTA

41. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Thermoionic Injectors LIMITATIONS Cathode Emissivity J < 20 A/cm 2  1 nC over 20 ps   cat > 9 mm Diode Saturation  Child-Langmuir Law I = kV 3/2 V=100 kV I=15 A with k=5. 10 -7  Field limited MATURE and CONSOLIDATED TECHNOLOGY

42. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Radio-Frequency Photo-Injectors LIMITATIONS Transverse plasma oscillations  Time dependent space charge effects dilution of projected emittance Photocathode and/or laser disuniform.  Space charge field non-linearities dilution of slice emittance Temperature emittance @ photocath. PROBLEMS Space and Time Jitters Laser beam quality Challenging Diagnostics (sub-ps) h Mature but non Consolidated Technology Stability, repetibility, ease of tuning UCLA/SLAC/BNL S-band next gen. RF Gun

43. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Plasma Guns: simulations results* (ongoing exp. @ LBL and Univ. of Michigan) - Brightness comparable to RF Photo-Injectors - fs bunches fully sinchronized to the laser - unproven technology - beam physics (in plasma) still to be explored Q=10 pC  t =20 fs  E =5%  n =5  m B n =1.5. 10 13 * T. Katsouleas et al., PRE 57 (1998) 5920 very sensitive to injection phase particle momentum vs. time

44. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ”

45. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Non-invasive Coronaric Angiography

46. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Experimental Results(Phase-I) A ps electron beam Energy: 14 MeV Energy: 14 MeV Bunch charge: 0.5 nC Bunch charge: 0.5 nC Pulse length: 3 ps(rms) Pulse length: 3 ps(rms) Focused beam size: 100  m(rms) Focused beam size: 100  m(rms) Pointing stability: 6  m (rms) Pointing stability: 6  m (rms) Time jitter: 1.4ps (rms) Time jitter: 1.4ps (rms) between e- bunch and fs laser pulse between e- bunch and fs laser pulse A fs laser beam Wavelength: 800nm Wavelength: 800nm Pulse energy: 85mJ/pulse Pulse energy: 85mJ/pulse Pulse length: 100fs(rms) Pulse length: 100fs(rms) Focused beam size: 20  m@90 o -collision Focused beam size: 20  m@90 o -collision 108  m@0 o -collision 108  m@0 o -collision A X-ray beam With the 0 o -collision With the 0 o -collision X-ray energy: 4.6keV(peak) X-ray energy: 4.6keV(peak) Pulse length (calc.): 3ps(rms), Pulse length (calc.): 3ps(rms), Intensity: 1.5x10 5 /pulse Intensity: 1.5x10 5 /pulse Intensity fluctuation: 10% Intensity fluctuation: 10% With the 90 o -collision X-ray energy: 2.3keV(peak) X-ray energy: 2.3keV(peak) Pulse length (calc.): 270fs(rms), Pulse length (calc.): 270fs(rms), Intensity: 1.4x10 4 /pulse Intensity: 1.4x10 4 /pulse Intensity fluctuation: 25% Intensity fluctuation: 25%

47. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Next Steps in Sumitomo-Festa Experiment Experimental Plan(Phase-II): High-energy X-rays: >30keV High-energy X-rays: >30keV increasing the accelerated electron energy: >40MeV increasing the accelerated electron energy: >40MeV High-intensity X-rays: >10 10 photons/s High-intensity X-rays: >10 10 photons/s Multi-bunch electron generation Multi-bunch electron generation 1J femtosecond laser with multi-collision 1J femtosecond laser with multi-collision High-stability X-rays: High-stability X-rays: A precise optical timing synchronization A precise optical timing synchronization The spatial profile of a 270fs-long X-ray pulse with a peak energy of 2.3keV was measured in 90 o Compton scattering as a function of the 2.3keV was measured in 90 o Compton scattering as a function of the laser polarization, and compared with the theoretical analysis. laser polarization, and compared with the theoretical analysis. The number of X-ray photons generated was obtained to be 1.4x10 4 /pulse. The stability of the X-ray intensity was measured to be 25%(rms).

48. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Sumitomo - Festa Collab. (Tokyo)

49. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” [Main Specifications] pulse energy 100 mJ pulse width 100 fs focused beam size 50  m pointing stability ±5  rad pulse repetition rate 10 Hz Compton chamber Pulse Compressor 3.6m x 1.5m TW femtosecond Ti:Sapphire laser

50. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” 1Terawatt Ti:sapphire laser system

51. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Stability of X-ray Intensity 25% (rms) within 10 min. within 10 min. Linearity of X-ray Intensity vs. Laser Energy **The results observed in 90 o collision**

52. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” MCP Phosphor Screen (10ns,410nm) Optical Lens ( f=100mm ) ICCD Camera （ Gate time: 10ns ） Window X-ray Imaging Measurement X-rays

53. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” electronselectrons Laser photons Scattered X-rays (A)the electron beam is in the plane of the laser polarization. (B)the electron beam is perpendicular to the plane of the laser polarization. (A)(B) 90-degree laser-Compton scatterings between a relativistic electron beam and a linear-polarized laser beam between a relativistic electron beam and a linear-polarized laser beam

54. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Anticipated Performances of Univ. of Tokyo - NERL experiment

55. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” Oscilla tor Pulse Stretcher Regenerative Amplifier Multi-pass Amplifier Pulse Compressor

56. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ” X-band advanced protoype

57. Capri, 3 Giugno 2003“ Fisica e Tecnologia degli Acceleratori e Tecniche Correlate ”