The Future of Photon Science and Free-Electron Lasers Ingolf Lindau Lund University and Stanford University MAX-Lab and Synchrotron Light Research KTH, June 1, 2012

The Vision… John Madey, 1971 “…possibility of partially coherent radiation sources in the … x-ray regions to beyond 10 keV.”

A new class of tunable high-power free-electron lasers. 29 March 1976 April 1971John M. J. Madey

Sov. Phys. Dokl. 24, 986 (1979) Optics Comm. 50, 373 (1984)

Concept of a free electron x-ray laser Replace storage ring by a linear accelerator allows compression of electron bunch – use once, then throw away Send electron bunch through a very long undulator very short bunch length micrometers spontaneous photons from back of bunch create order ordered electrons enhance stimulated photon emission amplified photons completely coherent Intensity scales as N e 2 or increased by 10 9

FEL Micro-Bunching Along Undulator UCLA S. Reiche SASE* FEL starts up from noise log (radiation power) distance Self-Amplified Spontaneous EmissionSelf-Amplified Spontaneous Emission electron beam photon beam beam dump undulator

Linac Coherent Light Source at SLAC Injector (35º) at 2-km point Existing 1/3 Linac (1 km) (with modifications) Near Experiment Hall Far Experiment Hall Undulator (130 m) X-FEL based on last 1-km of existing 3-km linac New e  Transfer Line (340 m) Å ( GeV) X-ray Transport Line (200 m) UCLA

132 meters of FEL Undulator Installed All 33 undulators installed July 22, 2009

 x,y  0.4  m (slice) I pk  3.0 kA  E /E  0.01% (slice) (25 of 33 undulators installed) Undulator Gain Length Measurement at 1.5 Å: 3.3 m

“Seeding” and “tapering” schemes x-rays e-beam

Linac Coherent Light Source at SLAC Injector (35º) at 2-km point Existing 1/3 Linac (1 km) (with modifications) Near Experiment Hall Far Experiment Hall Undulator (130 m) X-FEL based on last 1-km of existing 3-km linac New e  Transfer Line (340 m) Å ( GeV) X-ray Transport Line (200 m) UCLA

8.3 keV Å (13.64 GeV) LCLS-II 200m undulator LCLS low charge parameters 1.0 x 10  4 FWHMBW After self-seeding crystal 1.3 TW over 10 fs ~10 13 photons 1.3 TW over 10 fs ~10 13 photons W. Fawley, J. Frisch, Z. Huang, Y. Jiao, H.-D. Nuhn, C. Pellegrini, S. Reiche, J. Wu (FEL2011) 200 m undulator hall length compatible with self seeding & long tapered LCLS II undulator - TW power

PEP SPEAR3 2 km warm linac (33 GeV) + damping rings: PEP injection FACET LCLS 2 LCLS injector LCLS 1 km warm linac (16 GeV): LCLS 1 LCLS “1.5” LCLS 2 NLCTA (~400 MeV) x-band R&D, laser accel What is the Future of X-ray Sources at SLAC?

Emittances of Storage Rings and ERLs NSLS-II MAX-IV Petra-III Ultimate SRs (SPring-8, DESY, China) ERLs (Cornell, KEK) SSRL ALS, BESSY, Diamond, Soleil, SLS, SSRF ESRF, APS, SPring-8 500mA PEP-X SSRL Strategy and Plans Brightness ~ (Emit) 2

PETRA III 6 GeV, 2.3 km circumference, emittance= 1 nm-radian (2009)

PEP-X: Diffraction-Limited Storage Ring at SLAC 7BA cell Energy4.5-5 GeV Current200 mA Emittance (x/y)11/11 pm Bunch size (x/y, ID)7.4/7.4  m rms† Bunch length4 mm rms* Lifetime>2 h* Damping wigglers~90 m ID length (arc)~4 m ID length (straight)<100 m Beta at ID center, (x/y)4.92/0.8-5 m Circumference m Harmonic number3492 † Vertical beam size can be reduced towards 1  m *Harmonic cavity system would increase bunch length to ~8 mm and double the lifetime sufficient dynap for off-axis injection

High coherent fraction “Round” beams Short bunches (~5-10 ps RMS from low momentum compaction factor) Special operating modes could include: o few-turn, sub-ps bunch mode o turn mode with injection from superconducting linac operating without energy recovery (e.g. ~1 few GeV) o localized bunch compression systems in long straight sections o bunch tailoring with low alpha, non linear momentum compaction o lasing in an FEL located in a switched bypass o partial lasing at soft X-ray wavelengths using the stored beam “Long” lifetime : if the bunch dimensions are small enough Touschek lifetime increases (NSLS-II and MAX-IV may begin to see this effect) Damping wigglers to reduce emittance by ~x2 On-axis injection (maybe) and “swap-out” injection for small dynamic aperture USR Features

Ring sources are complementary to FELs