Free Electron Lasers driven by Laser Plasma Accelerators

Free Electron Lasers driven by Laser Plasma Accelerators Jeroen van Tilborg BELLA Center, LBNL Goal LPA FEL community: • Compact FEL @ reduced cost mid-scale labs • Synchronized to hyper-spectral sources Work supported by DOE HEP, DOE BES, NSF, and the Moore Foundation Office of Science 1 1

Laser-driven Plasma Accelerators enable room-size accelerator facilities Conventional structure: ~ 30 MV/m BELLA C Laser (Laser-driven) plasma structure: ~ 30, 000 MV/m enter Bldg 71 ALS LBNL Office of Science • 300 Me. V in few mm • Laser room (optical table) • Radiation cave (room-size) • BELLA Center multiple independent LPA systems in “east” part of building 71 2 22

Outline LPA FEL programs • Global • BELLA Center LPA • Emittance • Charge • Energy spread • Divergence Transport • Triplet • Active plasma lens • Space charge Office of Science Phase-space manipulation • Decompression • Transverse dispersion • CSR effects 3 Undulator • Strong focusing • Natural focusing 33

LPA community active with (incoherent) undulators since 2008 JENA: Schlenvoigt et al. Nat. Phys 2008 LBNL: Shaw et al. AAC Proceedings 2012 Resonance condition MPQ: Fuchs et al. Nat. Phys 2009 LOA: Lambert et al. FEL 2012 Office of Science 4 44

FEL lasing requires a dense electron beam with small energy spread https: //www. helmholtz-berlin. de/projects/berlinpro/erl-intro/linac-fel_en. html Ephoton Coupling vx ~ Ephoton Lethargy Huang & Kim PRSTAB 2007 Office of Science Gain length 5 FEL benefits from small gain length • Large ρ • High charge Q & short e-beam duration τ • Compact e-beam σr • Lower electron energy γ • Large K 0 • Correction Λ (emittance, energy spread, slippage, space charge, diffraction) • Seeding 55

Undulator considerations Embedded focusing keeps e-beam small • “Normal” undulator weak natural y-focusing • Strong focusing with added magnets • Cryo-cooled (larger K) • Different undulator technologies (RF, micro-undulator, optical, plasma-undulator, etc. ) X Periodic quadrupole fields FODO lattice Matched Embedded focusing undulator Y Office of Science εn=0. 35 micron 6 εn=1 micron εn=1. 0 66

LPA community: few-fs e-beams with >10 p. C charge, <10% spread Banerjee et al. Phys. Plasmas 2012 GAS JET Lundh et al. Nat. Phys. 2011 GAS JET ~75 Me. V 15 p. C, 1. 4 -1. 8 fs Buck et al. Nat. Phys. 2011 GAS JET ~20 Me. V Ibbotson et al. New. J. Phys. 2010 DISCHARGED CAPILLARY >50 p. C Δγ/γ~10 % 70 p. C Δγ/γ~5% >20 p. C Δγ/γ~5% Office of Science Liu et al. PRL 2011 DOUBLE GAS CELL Huang 7 presentation at FACET-II workshop 77

TREX laser system at LBNL: Capillary LPA and jet+blade LPA show promise 0 Blade position [mm] 0. 1 0. 2 Capillary LPA: high energy, high p. C/Me. V • <5% spread • 10 -30 p. C • 50 -200 Me. V Office of Science 8 K. Swanson et al. LBNL, in preparation related to: Buck et al. PRL 2013 88

Emittance measurements in LPA community: (sub)-micron emittances (not energy-integrated) Lower emittance Smaller averaged beam size Lower gain length (≤ 1 micron is considered good) Normalized Emittance at source: Size x Divergence x Gamma • Betatron X-ray spectrum (spectrum source size) • Sharp object in e-beam or photon beam (sharpness in spatial profile source size) • Energy-resolved quadrupole scans (size versus energy emittance) Plateau et al. PRL (2012) εn<2 micron Weingartner et al. PRSTAB (2012) εn=0. 2 micron εn=0. 1 micron Brunettti et al. PRL (2010) Office of Science(2012), Fritzler et al. PRL 9 (2004), Sears et al. PRSTAB (2010), Brunetti et al. PRL (2010) Plateau et al. PRL (2012), Weingartner et al. PRSTAB 99

Energy spread too large: phase-space manipulation Need to separate the various energies Maier et al. PRX 2012, Schroeder et al. FEL 2013 N Function of σγ y g+ g- x S Office of Science Smith et al. J. Appl. Phys. 1979, Huang et al. PRL 2012 10 10 10

Emittance degradation in transport (σθ – σγ coupling): E-beams needs to be captured early Drift Lens Drift 250 Me. V, 3 mrad, 0. 3% spread εn=0. 22 micron Migliorati et al. PRSTAB 2013, Loulergue et al. New. J. Phys. 2015 Ldrift=15 cm Coupling divergence & energy spread: • In drift coupling leads to degradation • Chromatic lens coupling leads to degradation • Solution: Capture e-beam early For 300 Me. V e-beam: Solenoid (2 T, L=20 cm): F=500 cm Quad triplet (500 Office of T/m, L=3 cm): F=20 cm Active plasma lens (2000 T/m, 11 L=3 cm): F=1. 7 cm Science Ldrift=3 cm 11 11

Energy acceptance of strong-focusing undulator: More slices matched if early capture source Average beamsize For early capture: • Larger energy bandwidth for “near-matching” • Important, since slippage over energy range • Alternative solution: design with many lenses Early capture (Lindstrom et al. PR AB 2016) Energy Matched, Energy = Target Energy Courtesy of S. Barber (LBNL) Office of Science Mismatched, Energy ≠ Target Energy 12 12 12

Capillary-discharge active plasma lens successfully demonstrated on LPA line Lens off Active Plasma Lens on • Introduced 1950 s (ion beams) • Symmetric focusing • Tunable • Gradients >3000 T/m Panofski et al. RSI 1950 van Tilborg et al. PRL 115, 184802 (2015) Office of Science 13 13 13

Capillary-discharge active plasma lens successfully demonstrated on LPA line Active Plasma Lens Office of Science Lens off 14 Lens on 14 14

Strong focusing field gradients observed! At peak current multiple in-lens oscillations 3600 T/m 300 T/m Office of van Tilborg et al. PRL 115, 184802 (2015) Science 15 15 15

Capillary lens: avoid wakefield degradation Transport: CSR & space charge need consideration Plasma wave Wakefields -Weak density dependence -Weaker effect for shorter beams, larger σr, shorter cap E-beam 250 Me. V emittance = 0. 19 micron σr=45 micron 20 p. C, L=2 micron Coherent Synchrotron Radiation (CSR) -Emittance degradation -Mainly from 1 st bend -Less bend will help Emittance increase x 2. 5 uspas. fnal. gov/materials/15 Rutgers/lecture_We 9. pdf Drift Space Charge (SC) -Mainly from source to 1 st bend -Weak for >100 Me. V, <100 p. C Lens=3400 T/m (~F) 80 T/m front-end variation Grüner et al. PRSTAB 2009 Office of Science 16 16 16

Numerous programs globally have interest to pursue LPA undulators & LPA FELs IMPACT (Spring 8) Shanghai (CAS/ Inst. Appl. Phys. ) Eu. Praxia DESY / LAOLA ELI - Beamlines LUNEX 5 (SOLEIL / LOA) Office of Science MPQ INFN: SPARC / FLAME 17 17 17

SIOM/SINAP, Shanghai: TGU undulator Quadrupole transport, chicane transverse • • N • Plan: demonstration experiment at 30 nm (400 Me. V, 6 m TGU) Transverse coherence could be compromised Seeding can be beneficial, part of plan y g+ g- x S Smith et al. J. Appl. Phys. (1979), Huang et al. PRL 2012, Liu et al. PRL 2011, Zhang et al. FEL 2013 Focusi ng opti cs LPA ch amber SIOM LPA setup (J. -S. Office. Liu) of Science Beam transpo rt TGU SINAP TGU assembly (D. Wang) 18 18 18

Hamburg (& ELI & Munich): Cryo-undulator w/o strong focusing, doublet transport, chicane longitudinal Maier et al. PRX 2012, Seggebrock et al PRSTAB 2013 Office of Science 19 19 19

COXINEL, Paris: Undulator without strong focusing Triplet + Quadruplet transport, chicane longitudinal Couprie et al. J. Phys. B. 2014, Khojyhan et al. NIMA 2016, Loulergue et al. New. J. Phys. 2015, André et al. IPAC 2016 Chromatic matching vs. Smallest beam photons e-beam Office of Science 20 • Collaboration SOLEIL & LOA • Undulator without strong focusing • Chicane for decompression • “Chromatic Matching” to capitalize on larger LPA spreads • First experiments on transport done • Aim for 200 nm, 50 nm later • Seeding is planned 20 20

BELLA Center: Undulator with embedded focusing Plasma lens + triplet transport, chicane longitudinal Schroeder et al. FEL 12 & FEL 13, Maier et al. PRX 2012 S. Barber, van Tilborg, Schroeder et al, in preparation Cap lens Quad triplet Chicane VISA λu=1. 8 cm, K=1. 26 4 m VISA 33. 3 T/m FODO lattice Office of for Accelerator Simulation, " Borland, "elegant: A Flexible SDDS-Compliant Code Advanced Photon Source LS-287, September. Science 2000. 21 1 M. Using ELEGANT 1 lattice optimized for matching into VISA undulator • Energy = 250 Me. V 21 • RMS divergence = 1 mrad 21

ELEGANT 1 transport + GENESIS 2 radiation generation simulations reveal role of chromatic & collective effects 125 Me. V, 25 p. C, 2. 5% d. E/E, 0. 3 micron emittance, 1 mrad, L=1 micron R 56=440 micron, λr=270 nm 220 Me. V 87 nm (9 th harmonic) 1 M. Borland, "elegant: A Flexible SDDS-Compliant Code for Accelerator Simulation, " Advanced Photon Source LS-287, September 2000. 2 http: //genesis. web. psi. ch/links. html Decompressed, 1. 0% d. E/E CSR + SC Decompressed Perfect de-chirper, CSR + SC Decompressed, 2. 5% d. E/E CSR + SC Spontaneous • Gain well above spontaneous • Smaller d. E/E strong improvement • Seeding, tapering, de-chirping will help LPA source Office of Science 22 Courtesy of S. Barber (LBNL) 22 22

BELLA LPA FEL (re-)construction under way Dedicated 100 TW 5 Hz laser system to drive LPA FEL • Funded by Moore Foundation New laser system and updated beam line • Funded by DOE BES Scientific staff • NSF students on transport & FEL • DOE HEP critical to transport studies to-date Undulator cave Laser room LPA cave LPA FEL team • Wim Leemans, Carl Schroeder & myself • Post-doc (Sam Barber) • Ph. D students • Collaboration with Rosenzweig team on undulators (UCLA & Radia. Beam) Power supplies Control room Laser room Office of Science 23 23 23

Summary & Acknowledgements bella. lbl. gov Summary • Multiple global programs funded to pursue LPA FELs • (Strong) Gain is realistic with LPA parameters • Transport plays critical role (capillary lens, triplets, chromatic effects) • Phase space manipulation needed (longitudinal or transverse separation) • Various undulator options available (regular planar, embedded focusing, cryo) • BELLA Center LPA FEL facility is under construction. Cap lens & triplet for transport, chicane, and strong-focusing VISA undulator • Exciting to see LPA community move to light source applications! Work supported by DOE HEP (Contract DE-AC 02 -05 CH 11231), DOE BES (Early Career), NSF (Grant PHY-1415596), and the Moore Foundation (Grant AWD 00000656) Office of Science 24 24