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The Future of Photon Science and Free-Electron Lasers Ingolf Lindau
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Transcript of The Future of Photon Science and Free-Electron Lasers Ingolf Lindau
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
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
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