The Future of Photon Science and Free-Electron Lasers

Ingolf LindauLund 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.”“…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 lengthmicrometers

spontaneous photons from back of bunch create order

ordered electronsenhance stimulated photon emission

amplified photonscompletely coherent

Intensity scales as Ne2 or increased by 109

FEL Micro-Bunching Along Undulator

UCLA

S. ReicheSASE* FEL starts up from noise

log (radiation power)

distance

• Self-Amplified Spontaneous Emission

electron beam

photon beam

beam dumpundulator

Linac Coherent Light Source at SLAC

Injector (35º)at 2-km point

Existing 1/3 Linac (1 km)(with modifications)

Near Experiment Hall

Far ExperimentHall

Undulator (130 m)

X-FEL based on last 1-km of existing 3-km linacX-FEL based on last 1-km of existing 3-km linac

New e- Transfer Line (340 m)

1.5-15 Å(14-4.3 GeV)

X-ray Transport Line (200 m)

UCLA

132 meters of FEL Undulator Installed

All 33 undulators installed

July 22, 2009

gex,y 0.4 mm (slice)Ipk 3.0 kAsE/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-rayse-beam

http://www-ssrl.slac.stanford.edu/

http://www-ssrl.slac.stanford.edu/

http://www-ssrl.slac.stanford.edu/

http://www-ssrl.slac.stanford.edu/

Linac Coherent Light Source at SLAC

Injector (35º)at 2-km point

Existing 1/3 Linac (1 km)(with modifications)

Near Experiment Hall

Far ExperimentHall

Undulator (130 m)

X-FEL based on last 1-km of existing 3-km linacX-FEL based on last 1-km of existing 3-km linac

New e- Transfer Line (340 m)

1.5-15 Å(14-4.3 GeV)

X-ray Transport Line (200 m)

UCLA

http://www-ssrl.slac.stanford.edu/

8.3 keV -- 1.5 Å (13.64 GeV)LCLS-II 200m undulatorLCLS low charge parameters

1.0 x 10-4 FWHMBW

After self-seeding crystal

1.3 TW over 10 fs ~1013 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

PEPSPEAR3

2 km warm linac (33 GeV) + damping rings:

PEP injectionFACETLCLS 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-8500mA

 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 SLACEnergy 4.5-5 GeVCurrent 200 mAEmittance (x/y) 11/11 pmBunch size (x/y, ID) 7.4/7.4 mm rms†Bunch length 4 mm rms*Lifetime >2 h*Damping wigglers ~90 mID length (arc) ~4 mID length (straight) <100 mBeta at ID center, (x/y) 4.92/0.8-5 mCircumference 2199.32 mHarmonic number 3492

† Vertical beam size can be reduced towards 1 mm

* 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 modeo 100-1000 turn mode with injection from superconducting linac operating without energy

recovery (e.g. ~1 mA @ few GeV) o localized bunch compression systems in long straight sectionso bunch tailoring with low alpha, non linear momentum compactiono lasing in an FEL located in a switched bypasso 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