J.B. Rosenzweig UCLA Dept. of Physics and Astronomy Future Light Sources 2010 SLAC March 3, 2010

1. Highlights of the 47th ICFA Workshop on the Physics and Applications of High Brightness Electron Beams J.B. Rosenzweig UCLA Dept. of Physics and Astronomy Future Light Sources 2010 SLAC March 3, 2010

2. Physics and Applications of High Brightness Electron BeamsMaui, November 16-19, 2009 • Latest in series resulting from joining “High Brightness” and “Arcidosso” workshops • Endorsed by ICFA subpanels on Beam Dynamics and Advanced and Novel Accelerators Mid-Pacific setting to encourage Asian participation

3. Committees Organizing committee Co-chairs • J. Rosenzweig (UCLA) • L. Palumbo (Univ. Roma “La Sapienza”) • M. Uesaka (U. Tokyo) • L. Serafini (INFN-Milano) • C. Brau (Univ. Vanderbilt) • H. Braun (PSI) • K-J. Kim (UC/ANL) • G. Dattoli (ENEA) • S. Milton (Sinc. Trieste/ANL) • S. Chattopadhay (Cockroft Inst.) • P. Emma (SLAC) • J. Rossbach (DESY) • W. Leemans (LBNL) • V. Yakimenko (BNL) Program committee • M. Ferrario (INFN-LNF), Chair • C. Pellegrini (UCLA) • W. Barletta (MIT) • Z. Huang (SLAC) • G. Krafft (JLAB) • M. Poole (Daresbury) • L. Giannessi (ENEA) • X. Wang (BNL) • R. Kishek (Univ. Maryland) • M. Eriksson (MAXLAB) • F. Gruner(LMU/MPQ) • T. Kamps (BESSY) • D. Giulietti (Univ. Pisa) • G. Hoffstaetter (Cornell) • F. Stephan (DESY) • T. Shintake (SPring-8)

4. History • 1999-Los Angeles: The Physics of High Brightness Beams - merging of ion/electron communities • 2002-Chia Laguna: The Physics of and Applications High Brightness Beams – joining of Arcidosso series, light source applicaitons • 2005-Erice: The Physics of and Applications High Brightness Beams. Theme: birth of the SASE FEL • 2009-Maui: The Physics of and Applications High Brightness Beams. Theme: New directions, plasma sources, etc.

5. Statistics • The workshop had 105 registered attendees from across the beam physics community, among them 10 students with partial support from the workshop. • The workshop received financial contributions from ANL, LBNL Sincrotrone Trieste, SLAC, UCLA, and the Univ. of Tokyo. • Conference secretariat headed by Carly Nguyen of UCLA, and included FrancesaCasarin and Daniela Ferrucci of INFNLNF. • Further information on the workshop is available at: http://pbpl.physics.ucla.edu/HBEB/index.html

6. Mission High brightness electron beams are playing an increasingly critical role in two frontier fields that are now yielding results that provoke considerable excitement and activity across the scientific community: radiation generation methods and advanced acceleration schemes. Such cutting edge radiation production methods include variations on the revolutionary 4th generation device, the free-electron laser, as well as inverse Compton scattering of intense lasers. These diverse approaches are thus able to create high peak and high average power light sources, with applications in ultrafast sciences and the Å level, as well as in nuclear and high-energy physics. Likewise, high brightness beams are at the center of many future accelerator schemes, e.g. based on high gradient electron and laser wakefields. Indeed, laser wakefield accelerators are now entering the proof-of-application phase, where unique light sources based on advanced acceleration schemes are enabled. The goal of this workshop is to provide a comparative study of the generation, manipulating, modeling and measuring of high brightness electron beams, and the multitude of underlying, interdisciplinary methods linking the physics of these beam systems to the physics of advanced applications.

7. Plenary talks and working groups * November 16 LCLS Injector Performance and Impact on Lasing - D. Dowell High Brightness Beam Measurements at PITZ - F. Stephan Superconducting RF Photoinjector Development - T. Kamps Intense Space Charge Effects of Relevance to FEL Injectors - R. Kishek On the Control of e-Beam Parameter with Laser Plasma Accelerators - V. Malka Overview of Advanced Cathodes for HBB - L. Cultrera Novel high brightness beyond photocathodes - C. Brau * November 17 Advanced Laser Pulse Shaping - H. Tomizawa Photoinjector Blow Out Regime Experiments at UCLA - P. Musumeci Velocity Bunching at SPARC - D. Filippetto Generation of Train of Short Electron Pulses for Wakefield Expts. - P. Muggli Beam Diagnosis at the Fs frontier - H. Loos Tomographic Phase-Space Mapping of High-Brightness Beams - D. Stratakis X-ray FEL Oscillator: Promises and Challenges - K-J. Kim * November 18 Emittance Compensation Theory & Experimental Results - C. Wang Thermal Beam Equilibria in Periodic Focusing Fields - C. Chen Physics of a 10 GeV laser-plasma accelerator - E. Esarey Brightness Characterization of Electro Beams from Plasma Injectors - A. Rossi Echo harmonic-techniques for Introducing NM Beam Structures - D. Xiang Overview of LWFA Experiments - W. Leemans High Average Power, High Brightness Electron Beam Sources - F. Sannibale * November 19 Overview of Thomson/Compton Sources - R. Kuroda Plasma and Dielectric Wakefield Acceleration Experiments at SLAC - M. Hogan Sub-fs Electron Pulses for FEL and PWFA applications - J. Rosenzweig Soft X-ray Undulator Radiation from Laser Accelerated Electrons - M. Fuchs Prospects for a Table Top FEL - C. Schroeder Laser-structure accelerators - B. Cowan The Coolest Beam in the World - J. Luiten 1. Sources, including photoinjectors and plasma-based sources
 2. Manipulation and diagnosis of high brightness beams 
 3. Theory and modeling, simulation challenges
 4. Applications of high brightness beams in advanced accelerators and light sources. Lets proceed from the cathode forward….

8. Overview of photocathodes - L. Cultrera (INFN-KNF)

9. Fundamental tension between QE and thermal emittance… Mitigated by using semi-conductor cathodes… but these are slower

10. Coatings on metal photocathodes: improving lifetime • Wide band-gap thin film coatings give interesting results • Example: CsBr, transmissive at 257 nm • MgF coatings improve Schottky by field inside coating

11. Emission in the visible: Yttrium • Photoemission at 400 nm • Lifetime issues in SPARC studies

12. Superconducting guns: Pb cathodes • Lead is excellent candidate cathode for SC guns • Usual tradeoff between QE and thermal emittance J. Smedley, T. Rao and J Sekutowicz, Phys. Rev. ST Accel. Beams, 11, 13502 (2008)

13. Semiconductor photocathodes • High QE through electron-phonon scattering (slow) • Coatings improve lifetime here too • Polarization with strained GaAs

14. Frontier: diamond amplifier cathode Gain over 200; beams emitted

15. Life after photocathodes -C. Brau (Vanderbilt) • Field emission approaches quantum brightness limit • Dedicated study of diamond tips… 6 nm tip radius

16. Improvements through gated array • Diamond FEA already FEL quality (high average power oscillator)

17. Diamond FEAs to be installed in SC guns

18. Carbon nanotubes approach quantum emission limit • Central role of adsorbate atoms in mediating emission

19. The coolest beams in the world -O.J. Luiten (Eindhoven) • Standard photocathodes at othe 0.1-1 eV temperature • Rydberg atom gas in laser trap gives orders of magnitude improvement possibility

20. Ultra-cold beam experiments • First tests give three orders of magnitude temperature improvement

21. Immediate applications • Ultra cold ion beams • Ultra-fast electron diffraction

22. Ultrashort laser pulses on the cathode: blow-out regime and multiphoton photoemission – P. Musumeci (UCLA) • Blowout regime dynamically produces high quality electron bunch – ellipsoidal shape • Very high 6D brightness with low Q Deflector enabled observations

23. Application: ultra-relativistic electron diffraction

24. Multiphoton photoemission • Photoemission observed in IR! • Lower efficiency compensated by regaining uv conversion losses

25. Superconducting RF Photoinjector Development -- T. Kamps (HZB) • Obvious approach to high average current photoinjectors for FEL • BNL, Berlin, Dresden… • Challenges: cathode, beam focusing

26. High Average Power, High Brightness Electron Beam Sources - F. Sannibale (LBNL) • Normal conducting option presented • Cooling gives strong field limitations

27. LCLS Injector Performance and Impact on Lasing- D. Dowell (SLAC) • Remains the gold standard • Many problems in high field photoinjectors mitigated

28. Very low charge mode at LCLS Higher brightness, ultra-short pulse for advanced FEL

29. Longitudinal phase space schematic for velocity bunching Velocity bunching at SPARC –D. Fillipetto (INFN-LNF) • Advanced compression technique, avoids “the bends” • Compression x3 with little emittance growth

30. An X-Ray FEL Oscillator: Promises and Challenges -- Kwang-Je Kim (Chicago/ANL) • An X-ray pulse is stored in a diamond cavity • multi-pass gain & spectral cleaning • Provide transform limited BW • Zig-zag path cavity for wavelength tuning

31. Compelling brightness argument

32. Low charge, high brightness beams… again

33. Plasma and Dielectric WakefieldAcceleration Experiments at -- M. Hogan Enormous accomplishments at FFTB, looking towards FACET

34. A Light Source Scenario using Dielectric Wakes Symmetric beam R<2 • Pulse train may not be needed or desirable… • Instead, look for enhanced transformer ratio with ramped beam • Does this work with multi-mode DWA? • Scenario: 500-1000 MeV ramped driver; 5-10 GeV FEL injector in <10 m Ramped beam R>>2 Ramped beam R>>2

35. A FACET scenario • Charge: 3 nC • Ramp: L=2.5 mm • Energy: 500 MeV • Structure: a=100 mm, b=100 mm,e=3.8 • Fundamental f=0.74 THz • Performance: >GV/maccel., R=24 (12 GeV possible) Sag in wake due to multi-mode

36. TV/m plasma wakefield accelerator using low charge, ultra-short beam –-J. Rosenzweig, UCLA • Original proposal to scale beam charge to pC level • Velocity + chicane bunching preserves <3-6 E-8 emittance • Single spike FEL, sub-fs (few 100 attosecond) operation

37. Use Table-top XFEL undulator? • LMU MPQ-centered collaboration (BESSY, LBNL, UCLA, etc.) • UCLA collaboration on advanced hybrid cryo-undulator (Pr-based, SmCo sheath, Fe pole), 9 mm period, >2 T • Need short lu high field undulator for X-rays @1 GeV – critical for traditional linac sources too… • With ultra-high brightness beam, one may have very compact, extended capability FELs Simulated 9 mm cryounduator performance at 30K (Maxwell, Radia, Pandira)

38. Example: SPARX w/sub-fs pulse • Wavelength reduction (3 nm->6.5 Å) • Ultra-short saturation length (10 m) • LCLS photon reach at 2.1 GeV on 5th harmonic Simulated performance on fundamental MW peak power at 1.5 Å, 5th harmonic

39. Example: LCLS w/sub-fs pulse • Use even shorter 0.25 pC beam, 150 as pulse • Single spike w/standard LCLS undulator • Obtain ultra-compact “LCLS” at 4.3 GeV • Extend energy reach to 83 keV (0.15Å) Gain evolution at 13.6 GeV, 0.15 Å Gain evolution for 1.5 Å 4.3 GeV (0.25 pC)

40. Ultra-short, high brightness beam:IR wavelength PWFA • Ultra-high brightness, fs beams impact HEP strongly… • Use 20 pC LCLS beam in high n plasma • In “blowout” regime: total rarefaction of plasma e-s • Beam denser than plasma • Very nonlinear plasma dynamics • Pure ion column focusing for e-s • Linac-style EM acceleration • General measure of nonlinearity: Wakes in blown out region MAGIC simulation of blowout PWFA case

41. Optimized excitation at LCLS • Beam must be short and narrow compared to plasma skin depth • In this case implies , blowout • With 2 fs LCLS beam we should choose • For 20 pC beam, we have • Linear “Cerenkov” scaling • 1 TV/m fields (converted Er) • Collaboration initiated • UCLA-SLAC-USC • Basic science: coherent radiation, BSI ionization OOPIC simulation of LCLS case

42. Laser-driven undulator source -- M. Fuchs (MPQ) • Plasma acceleration gives 1st observed X-rays • W. Leemans discusses application further…

43. Aloha from Maui • Mahalo: thank to all for coming, and contributing at such a high level • Look for updates on publications on website • JACOW submission formalities, open soon • Particular emphasis on invited, summary talks (6 pages) • PRSTAB special option • To the farther future...

44. First suggestion (from D. Stratakis): Crete 2011 We are open to all ideas that fit the theme!