1. Advanced Accelerator R&D program Philippe Piot Fermilab & Northern Illinois University Fermilab Institutional Review June 6-9, 2011 Fermilab Institutional Review, June 6-9, 2011

2. Outline Introduction, Accelerator science at the A0 photoinjector (A0PI) & recent achievements, Opportunity for Accelerator R&D at the Superconducting Test Facility (STF), Conclusion. 2 Fermilab Institutional Review, June 6-9, 2011

3. Introduction: current goals & achievements Education:  Contributed to the training of ~11 PhD students (~1/3 of accelerator science students at Fermilab). Technology:  Designed, built, delivered an injector (rf-gun + injector beamline components) for TESLA test facility (TTF-1) at DESY,  Laser capable of providing ILC-type macropulse format. Science:  Characterization of a L-band gun over a wide range of operating parameter (1999),  Observation of wakefield via electro-optical imaging (2000),  Generation of angular-momentum dominated beams (2002),  Flat beam production in a photoinjector (2000-2003),  Plasma-wakefield acceleration and plasma lens in under-dense regime, (2003-2004),  Emittance exchange between the horizontal and longitudinal degrees of freedom (2008-2010),  Pulse shaping with emittance-exchanger beamline (2010-2011). 3 Fermilab Institutional Review, June 6-9, 2011

4. 4 A0/NML students Graduated: 1.Eric Colby, PhD, UCLA, 1997 (J. Rosenzweig) 2.Alan Fry, PhD, U. of Rochester, 1998 (A. Melissinos) 3.Michael Fitch, PhD, U. of Rochester, 2000 (A. Melissinos) 4.Jean-Paul Carneiro, PhD, U. Paris XI, France, 2001 (J. Le Duff) 5.Dan Bollinger, MS, Northern Illinois University, 2005 (C. Bohn) 6.Yin-e Sun, PhD, U. of Chicago, 2005 (K.-J. Kim) 7.R. Tikhoplav, PhD, U. of Rochester, 2006 (A. Melissinos) 8.M. Thompson, PhD, UCLA, 2007 (J. Rosenzweig) 9.Arthur Paytan, MS, Yerevan State University, Armenia, 2008 (E. Laziev) 10.Timothy Koeth, PhD, Rutgers University, 2009 (S. Schnetzer) Present: 1.T. Maxwell, Northern Illinois University, 2011 (P. Piot) 2.A. Johnson, FNAL-technician at Northern Illinois University (P. Piot) 3.C. Prokop, PhD, Northern Illinois University [NML, sponsored by LANL], 2012? (P. Piot) 4.F. Lemery, PhD, Northern Illinois University [NML, sponsored by DTRA], 2013 (P Piot) People Fellows: Markus Huening, 2002-2004 (from DESY, now at DESY) Philippe Piot, 2002-2005 (from DESY, now at NIU-FNAL) Yin-e Sun, since 2008 (from Argonne) Charles Thangaraj, since 2010 (from U. Maryland) Undergraduates:  summer students from SIST, Sup-Areo Toulouse, Politecnico Milano, Uni. Torino Fermilab Institutional Review, June 6-9, 2011 Sponsored by FNAL/ University PhD program

5. 5 Selected recent publications (2010-2011) 1. P. Piot, et al.,” Observation of Coherently-Enhanced Tunable Narrow-Band Terahertz Transition Radiation from a Relativistic Sub-Picosecond Electron Bunch Train”, APL accepted, in press (2011). 2. T. Maxwell, et al., “Synchronization and Jitter Studies of a Titanium-sapphire Laser at the A0 Photoinjector”, PAC11 (2011) 3. R. Thurman-Keup et al, “Transverse Emittance and Phase Space Program Developed for Use at the Fermilab A0 Photoinjector”, PAC 11 (2011). 4. T. Thangaraj, “Experimental Studies on Coherent Synchrotron Radiation in the Emittance Exchange Line at the Fermilab A0 Photoinjector”, PAC11 (2011). 5. A. Lumpkin, et al., “Beam-Profiling Tests with the NML Prototype Station at the Fermilab A0 Photoinjector”, PAC11 (2011). 6. J. Ruan, et al., “First observation of the exchange of transverse and longitudinal emittances”, PRL accepted, in press (2011). 7. P. Piot et al., “Generation of relativistic electron bunches with arbitrary current distribution via transverse-to-longitudinal phase space exchange”, ArXiv:1007.4499, PRSTAB 14 022801 (2011). 8. Y.-E Sun et al., “Formation of train of sub-picosecond bunches with variable spacing using a transverse to longitudinal phase space exchange”, PRL 105 234801(2010). 9. A. Lumpkin, et al., “Upgrades of beam diagnostics in support of emittance-exchange experiments at the FNAL A0 photoinjector”, Proc. FEL10 (2010); PRSTAB accepted, in press (2011). 10. P. Piot et al., “Transverse-to-longitudinal phase space exchange: a versatile tool for shaping the current and energy profile of relativistic electron bunches”, Proc. AAC10 (2010). 11. T. Thangaraj, et al., “Experimental study of coherent synchrotron radiation in the emittance-exchange line of the A0 photoinjector”, Proc. AAC10 (2010). 12. Y.-E Sun, et al., “Experimental Generation of Longitudinally-modulated Electron Beams using an Emittance-exchange Technique”, Proc. IPAC10, 4313 (2010). 13. M. Thompson, et al., “Observations of low-aberration plasma lens focusing of relativistic electron beams at the under-dense threshold”, Phys. Plasmas 17, 073105 (2010). 14. A. Johnson, et al., “Demonstration of Transverse-to-longitudinal Emittance Exchange at the Fermilab Photoinjector”, Proc. IPAC10, 4614 (2010). 15. Y.-E Sun, et al., “Conversion of a transverse density modulation into a longitudinal modulation using a emittance exchange technique”, Proc, HBEB09, ArXiV:1003.3126 (2010). 16. A. Lumpkin, et al., “OTR polarization effects in beam-profile monitor at the A0 photoinjector”, Proc. BIW10 (2010). Fermilab Institutional Review, June 6-9, 2011

6. 6 A0 photoinjector (A0PI): introduction Electron accelerator based on 1.3 GHz rf-gun with Cs 2 Te photocathode → Q< 10 nC (up to ~100 bunches) TESLA SCRF cavity → E=16 MeV Emittance exchange beamline (  x,  z )  (  z,  x ) Round-to-flat-beam transformer   x /  y ~100 Extensive diagnostics

7. [J. Ruan et al., PRL (2011), in press] Observed emittance exchange between the horizontal and the longitudinal phase spaces Energy spread Bunch duration measurement with streak camera A0PI: phase space manipulations 7

8. A0PI: current-profile shaping Generated a train of micro- bunches with sub-ps sepa- ration using slits Applications:  generation of narrow-band coherent radiation,  Resonant excitation of wake-fields in PWFA and DWFA. EEX beamline Transversely- shaped beam Longitudinally- shaped beam [ Y.-E. Sun et al., PRL 105, 234801 (2010) P. Piot et al., PRSTAB 14, 022801 (2011)] 8

9. A0PI: narrow-band Terahertz radiation Important application of sub-ps bunch train generation: production of tunable narrow band THz radiation, Extensive use in medical imaging, condensed matter, etc…, At A0PI, demonstra- ted the production of narrowband THz transition radiation. Pre-bunching the beam at smaller wavelength could improve the performance of short-wavelengths FELs. [P. Piot et al., APL (2011), in press] 9 Fermilab Institutional Review, June 6-9, 2011

10. Electro-optical imaging of velocity fields associated to the electron bunch:  Laser synchronized,  First signal on 06/02/2011! Improved beam density monitor for the STF@NML (collaboration with RadiaBeam Tech.) laser OTR < 300 fs relative jitter [T. Maxwell, et al., PAC09 (2009) and PAC (2011)] 10 Fermilab Institutional Review, June 6-9, 2011 A0PI: on-going beam dynamics diagnostics [A. Lumpkin, et al., PAC11 (2011)]

11. A0PI: on-going beam dynamics experiments Generation of uniformly-filled 3D ellipsoidal bunch from Cs 2 Te photocathode:  Preliminary experiment completed,  final data taking in 06/2011 with improved diagnostics. Investigation of coherent syn- chrotron radiation and bunch compression in the emittance- exchanging beamline. time y N 100 pC 600 pC 11 Fermilab Institutional Review, June 6-9, 2011 cathode <100 fs laser bunch [T. Thangaraj, et al., PAC11 (2011)] [P.Piot et al., (2011)]

12. A0PI and its transition to the high- brightness electron source Lab (HBESL) Upon removal of the SCRF booster cavity  A0 will serve as an electron source development laboratory (called HBESL) Research focuses include  Optimization of beam brightness through advanced laser shaping techniques,  R&D toward field emission sources (field-emission array [Vanderbilt]) or Carbon nanotubes [Radiabeam Tech. phase II SBIR (pending)],  Low energies phase-space tailoring,  Compact MeV-scale accelerators using advanced acceleration concepts (direct-field laser acceleration [MIT/DESY/NIU], dielectric wakefield tests)  Support and R&D for improvements of STF@NML facility electron source performances. 12 Fermilab Institutional Review, June 6-9, 2011

13. STF@NML: Overview <40 MeV < 750 MeV< 1 GeV 13 Fermilab Institutional Review, June 6-9, 2011

14. STF@NML: introduction Variable energy from ~40 to ~1 GeV, High-repetition rate (1-ms trains):  Exploration of dynamical effects in beam-driven acceleration methods. L-band SCRF linac:  Well suited for beam-driven acceleration, Photoinjector source:  Provides low-emittance beam, Arbitrary emittance partition:  repartition of phase spaces to match final applications,  Tailored current profiles. A0 AWA ATF NML FACET A0 AWA ATF NML FACET Peak brightness Average brightness Peak brightness Average brightness Energy (MeV) FLASH (DESY) Fermilab Institutional Review, June 6-9, 2011

15. Beam dynamics simulation for STF@NML Single-particle lattice design simulation with ELEGANT, Multi-particle simulations using Impact-T/Z (SCIDAC), Astra and CsrTrack (DESY). [C. Prokop et al., Proceedings of PAC11, in press] 15 Fermilab Institutional Review, June 6-9, 2011

16. Bunch compression First phase incorporates a single- stage compression at 40 MeV Eventually, bunch compression will be improved staged:  2 nd bunch compressor at high-energy,  3 rd harmonic cavity in injector for bet- ter control of longitudinal phase space [C. Prokop et al., Proceedings of PAC11, in press] 16 Q= 3.2 1.0 0.2 0.02 nC Q=3.2 nC LiTrack calculations

17. Phase space manipulations at STF@NML Advanced beam manipulations:  Flat beams,  Emittance exchange,  Introduction of nonlinear phase space distortions. Examples of applications:  Short wavelength “seeded” FEL using prebunched beams,  Image charge undulator tests,  Advanced acceleration in slab dielectric-loaded structures. [A. Zholents, PAC11 (2011)] 17 Fermilab Institutional Review, June 6-9, 2011 [D. Mihalcea, PAC11 (2011)]

18. Experiments currently under consideration at STF@NML Short term:  Production of X-ray using chan- neling radiation from bright e- beams (40-MeV area) to address DOD’s challenge 10 12 photons /s/mm 2 /mrad 2 /0.1%BW in 0.01 m 3, [Vanderbilt University/NIU/FNAL]  Flat beams in dielectric slab structures (40 or 250 MeV) [NIU],  IOTA (next slide) using a ~150 MeV e- beam [FNAL]. Longer terms:  Versatile emittance exchanger/ pulse shaper,  Short-wavelength “seeded” FELs [interest from ANL, LANL, LBNL]  Many other possible applications discussed at a workshop in 2009. 18 Fermilab Institutional Review, June 6-9, 2011 http://apc.fnal.gov/ARDWS/index.html

19. Integrable Optics Test Accelerator (IOTA) at STF@NML The STF@NML facility provides the needed infrastructure to test other concepts IOTA, a compact ring dedicated to test integrable optics, will use a 150-MeV beam from STF@NML. 19 Fermilab Institutional Review, June 6-9, 2011

20. Integrable Optics Test Accelerator (IOTA) Nonlinear integrable accelerator optics are being developed to enable stable operation of a completely nonlinear machine (tune spread up to 50%) Accelerators with very large tune spread will push the intensity limits of storage rings by suppressing collective instabilities through “better” Landau damping. [Danilov, Nagaitsev, Valishev, 2011 see also PRSTAB 2010] 20 Fermilab Institutional Review, June 6-9, 2011

21. Timeline 10/2011 reconfiguration as HBESL EOS EEX Ellipsoidal bunch HBESL moves to IARC HBESL operation: 1. CsTe studies, 2. Ellipsoidal bunch with shaped laser, 3. Diamond field-emission array, 4. Two-frequency rf-gun, (w. Radiabeam Tech.)? 5. Direct-field laser acceleration. (pending TW laser?) Construction work cryomodule 1 RF tests 09/2012 201220132014 First beam A0/HBESL STF@NML Commissioning with cryomodule 1 (250 MeV) 09/2013 Beam dynamics studies: 1. Beam characterization, 2. 40-MeV compression, 3. Cryomodule/LLRF studies, 4. Flat beams to 40/250 MeV 5. Channeling radiation with 40 MeV beam? cryomodule 2 Installation?

22. Summary Over the last decade, Fermilab has been very active in AARD: - e- source for linear collider + short-wavelength FELs, - novel phase space manipulations: flat beam, emittance exchange, current tailoring technique. Phase space manipulations pioneered at A0PI have many applications: beam-driven wakefield acceleration, and novel light source concepts,… The STF@NML will include most of these manipulations  flexible, powerful facility to support a vibrant AARD program. The A0 photoinjector will be transformed into a high- brightness electron source laboratory:  explore novel cathodes and acceleration concepts,  support gun R&D to improve the performance of STF@NML. 22 Fermilab Institutional Review, June 6-9, 2011