x Ø4 7¾+ + $% ,x Ô ¥ )clinac coherent light source h.n. chapman et al., nature 470, 73 (2011)...
TRANSCRIPT
http://www.sciencemuseum.org.uk/Centenary.aspx
In a public poll by the Science Museum in London: what is the most significant scientific invention?
(1909-2009)
Bright xBright x--rayray sources from relativistic electronssources from relativistic electrons
Electrons emit with random phase radiation intensity N( is Lorentz factor, N is number of electrons ~109) Electrons emit with random phase radiation intensity N( is Lorentz factor, N is number of electrons ~109)
Synchrotron radiation Undulator radiation
• Produced by resonant interaction of a relativistic electron beam with EM radiation in an undulator
Free Free Electron Electron Laser (FEL)Laser (FEL)
electron electron beambeam
photon photon beambeam
ee beam beam dumpdumpundulatorundulator
1
• Radiation intensity N2
• Tunable, Powerful, Coherent radiation sources
Talk outlineTalk outline
IntroductionIntroduction
FEL physicsFEL physics
Ultrafast xUltrafast x--ray scienceray science
LCLS: the first hard xLCLS: the first hard x--ray laserray laser
Worldwide development and Future R&DWorldwide development and Future R&D
The The beginning…beginning…
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.”
zz
xx
Due to sustained interaction, some electrons lose energy, Due to sustained interaction, some electrons lose energy, while others gain while others gain energy modulation at energy modulation at 11
ee losing losing energy slow down, and energy slow down, and ee gaining energy catch up gaining energy catch up density modulation at density modulation at 11 ((microbunchingmicrobunching))
MicrobunchedMicrobunched beam radiates coherently at beam radiates coherently at 11, enhancing , enhancing the process the process exponential growth of radiation powerexponential growth of radiation power
uu
eeee11 xx--rayray
Electrons Electrons slipslip behind EM wave by behind EM wave by 11 per undulator period (per undulator period ( uu))++ ++ ++
++ ++ ++
KK//
vvxxEExx > 0> 0
++
ResonantResonantInteraction Interaction of of Field Field with with ElectronsElectrons
EE tt
EE tt
vvxxEExx > > 00 vvxxEExx > > 00vvxxEExx > 0> 0 vvxxEExx > > 00
FEL MicroFEL Micro--Bunching Along UndulatorBunching Along Undulator
S. ReicheS. Reicheloglog
(radiation (radiation power)power)
distancedistance
electron electron beambeam
photon photon beambeam
ee beam beam dumpdumpundulatorundulator
SASE FEL Electron Beam RequirementsSASE FEL Electron Beam Requirements
FEL grows exponentially with undulator distance z
peak current
only if beam energy spread << 10-3
power gain length
beam emittance
FEL power reaches saturation at ~ 20 LGSASE performance depends exponentially on e-
beam qualities
Why a Why a LinacLinac--Based FreeBased Free--Electron Electron Laser Laser ??
* * KondratenkoKondratenko, , SaldinSaldin 1980; 1980; BonifacioBonifacio, Pellegrini 1984, Pellegrini 1984
Use Use SASESASE* * (Self(Self--Amplified Spontaneous Emission) Amplified Spontaneous Emission) no mirrors or seed laser at 1 Å wavelengthsno mirrors or seed laser at 1 Å wavelengths
Longitudinal Longitudinal emittanceemittance from from linaclinac is ~10is ~1033 smaller than ringsmaller than ring
Bunch length can approach 100 Bunch length can approach 100 fsecfsec with small energy spreadwith small energy spread
Experience from linear collider operation and study (Experience from linear collider operation and study (SLCSLC,,TESLATESLA,, JLCJLC,, NLCNLC,, CLICCLIC,, ILCILC))
Electron bunch can be compressed to a few kA Electron bunch can be compressed to a few kA
Recent advances in highRecent advances in high--brightness RF photocathode gunsbrightness RF photocathode guns
OperationalUnder constructionProposed
OperationalUnder constructionProposed
SCSS-TA &XFEL/SPring-8
PAL XFEL
SDUV &SXFEL
LCLS &LCLS-II
DUV-FEL
SwissFEL
FERMI@ELETTRA
FLASH &European XFEL SPARC &
SPARX
Worldwide FELs
NGLS
WiFEL
Worldwide FELs
DUV FELSCSS-TA
SDUV-FELPolFELJLamp
FLASHFERMI@ELETTRA
SPARXSXFELLCLS-IIMAX IV
NGLS (LBNL)WiFEL
SwissFEL
LCLSXFEL/SPRing-8European XFEL
PAL XFEL
Era of XEra of X--ray Lasersray LasersProbe the Probe the ultrasmallultrasmall Capture the ultrafastCapture the ultrafast
nanoscale dynamics occursat femtosecond timescale
1 1 femtofemto--second (fs)second (fs) = = 1010 1515 secsec 0.3 0.3 mm
tt 1 sec1 sec
Time ScalesTime Scales
In Neils Bohr’s 1913 model of the Hydrogenatom it takes about 150 as for an electronto orbit the proton..–– NatureNature,, 20042004
100 100 femtofemto--second (fs) = second (fs) = 1010 1313 sec sec 30 30 mm
E. Muybridge and L. Stanford in 1878E. Muybridge and L. Stanford in 1878
E. Muybridge, E. Muybridge, Animals in MotionAnimals in Motion, ed. L. S. Brown (Dover Pub. Co., New York 1957)., ed. L. S. Brown (Dover Pub. Co., New York 1957).Muybridge used spark photography to freeze this ‘ultraMuybridge used spark photography to freeze this ‘ultra--fast’ processfast’ process
E. MuybridgeE. Muybridge
…they disagree whether all feet leave the ground during gallop……they disagree whether all feet leave the ground during gallop…
Understanding Understanding of a fast of a fast process by process by freezing the freezing the action…action…
L. StanfordL. Stanford
Coulomb Explosion of Lysozyme (50 fs)Coulomb Explosion of Lysozyme (50 fs)
JJ. . HajduHajdu,, Uppsala U.Uppsala U.
Atomic and Atomic and molecular molecular dynamics occur dynamics occur at the at the fsecfsec--scalescale
…which is being imaged …which is being imaged with intense with intense xx--rays rays BEFOREBEFORE its destructionits destruction
A Femto-Camera for Molecular Movies
molecules
optical laser
x-ray laser
before afterthe transition state
LLinac inac CCoherent oherent LLight ight SSource (ource (LCLSLCLS) ) at at SLACSLACLLinac inac CCoherent oherent LLight ight SSource (ource (LCLSLCLS) ) at at SLACSLAC
Injector (35Injector (35ºº))at 2at 2--km pointkm point
Existing 1/3 Linac (1 km)Existing 1/3 Linac (1 km)(with modifications)(with modifications)
Near Experiment HallNear Experiment Hall
Far ExperimentFar ExperimentHallHall
Undulator (130 m)Undulator (130 m)
XX--FEL based on last 1FEL based on last 1--km of existing 3km of existing 3--km linackm linacXX--FEL based on last 1FEL based on last 1--km of existing 3km of existing 3--km linackm linac
New New ee Transfer Line (340 m)Transfer Line (340 m)
1.51.5--15 Å15 Å(14(14--4.3 GeV)4.3 GeV)
XX--ray ray Transport Transport Line (200 m)Line (200 m)
Proposed by C. Pellegrini in 1992
SLAC linac tunnelSLAC linac tunnel research yardresearch yard
LinacLinac--00L L =6 m=6 m
LinacLinac--11L L 9 m9 mrf rf 2525°°
LinacLinac--22L L 330 m330 m
rf rf 4141°°
LinacLinac--33L L 550 m550 m
rf rf 00°°
BC1BC1L L 6 m6 m
RR5656 39 mm39 mm
BC2BC2L L 22 m22 m
RR5656 25 mm25 mm DL2 DL2 L L =275 m=275 mRR56 56 0 0
DL1DL1L L 12 m12 mRR56 56 0 0
undulatorundulatorL L =130 m=130 m
6 MeV6 MeVz z 0.83 mm0.83 mm
0.05 %0.05 %
135 MeV135 MeVz z 0.83 mm0.83 mm
0.10 %0.10 %
250 MeV250 MeVz z 0.19 mm0.19 mm
1.6 %1.6 %
4.30 GeV4.30 GeVz z 0.022 mm0.022 mm
0.71 %0.71 %
13.6 GeV13.6 GeVz z 0.022 mm0.022 mm
0.01 %0.01 %
LinacLinac--XXL L =0.6 m=0.6 mrfrf= =
21-1b,c,d
...existinglinac
rfrfgungun
21-3b24-6dX 25-1a
30-8c
undulatorundulator
beam parked here
beam parked here
Generation of low emittance beamPreservation of 6D brightness in accelerator/compressorUndulator tolerance and trajectory control
LCLS accelerator (commissioning started 2007)LCLS accelerator (commissioning started 2007)
Don’t underestimate 40+ years SLAC linac experience
Cavity BPM (<0.5 m)Cavity BPM (<0.5 m)QuadrupolemagnetQuadrupolemagnet
3.4-mundulatormagnet
3.4-mundulatormagnet
Beam Finder Wire (BFW)Beam Finder Wire (BFW)
cam-based 5-DOF motion control –0.7 micron backlash
cam-based 5-DOF motion control –0.7 micron backlash
X-translation (in/out)
X-translation (in/out)
Wire Position MonitorWire Position Monitor
Hydraulic Level SystemHydraulic Level System
One of 33 One of 33 undulatorsundulators with controls with controls
First lasing and FEL saturation 1.5 First lasing and FEL saturation 1.5 ÅÅ
x,yx,y = 0.4 = 0.4 m (slice)m (slice)IIpkpk = 3.0 kA= 3.0 kA
EE//EE = 0.01% (slice)= 0.01% (slice)
((25 of 33 25 of 33 undulatorsundulatorsinstalled)installed)
LLGG 3.3 3.3 m (measured)m (measured)LLGG == 4.5 m (design)4.5 m (design)
First Lasing (April 10, 2009)First Lasing (April 10, 2009)FEL saturation observed: April 14, 2009
P. Emma et al., Nature Photonics 2010
LCLSLCLS AchievementsAchievements
Exceptional Exceptional ee beam quality from RF gun (beam quality from RF gun ( x,yx,y 0.4 0.4 mm))
Pulse length Pulse length easilyeasily adjustable for users (adjustable for users (60 60 -- 500 500 fs FWHM)fs FWHM)
LowLow--charge mode (20 charge mode (20 pCpC) allows <) allows <1010 fsfs pulses (~0.15 pulses (~0.15 mJmJ))
Wider photon energy range: Wider photon energy range: 480 480 -- 10000 10000 eV (design was: eV (design was:
830 830 -- 8300 eV)8300 eV)
Peak FEL power >Peak FEL power >7070 GW (10 GW in CDR)GW (10 GW in CDR)
Pulse energy up to Pulse energy up to 4 4 mJmJ (2 (2 mJmJ in CDR)in CDR)
96.796.7% accelerator availability, % accelerator availability, 94.894.8% photon availability% photon availability
120 120 fsfs pump probe synchronization has been achieved pump probe synchronization has been achieved
Far Experimental Hall
Near Experimental Hall
AMOSXRXPP
CXIXCSMEC
X-ray Transport Tunnel
200 mStart of
operation
Oct-09AMO
Fall-11XCSJune-11*CXI
October-10XPPMay-10SXR
MEC Fall-11
LCLS Experimental HallsLCLS Experimental Halls
Many high impact publications in Nature, PRL…
D. Wang et al., Science 324, 5931 (2009) •
A new paradigm opens up macromolecular structure determination to systems too small or radiation sensitive for synchrotron studies, and may save years of effort in crystallization trials
Single-shot diffraction patterns are recorded with 70 fs pulses. Coherent diffraction
shows the crystal size is sub-micron (top left) and that the crystal has a perfect lattice. Individual shots are oriented in 3D and
combined to build up the full information content of the underlying macromolecule (top right). This first demonstration was
carried out at 2 keV photon energy, limiting the resolution to about 9 Å. (This will be
improved with the dedicated CXI instrument.) The quality of the data are demonstrated by carrying out molecular
replacement refinement (right). Structural details such as helices can be observed.
• The ultrafast LCLS x-ray pulses allow us to record “diffraction before destruction”
where information is obtained before the onset of structural damage.
• Diffraction can be measured from sub-micron crystals containing less than a
thousand molecules.
• Demonstrated using Photosystem I, a membrane protein, key to
photosynthesis, that is extremely difficult to grow into large crystals.
• 30 single-crystal patterns per second were recorded from a liquid stream
carrying a suspension of nanocrystals. 15,000 of these were indexed and
combined into a full diffraction pattern which was analyzed with standard tools.
• Data are collected at room temperature. No cryogenic cooling or stabilization
required.
Linac Coherent Light Source H.N. Chapman et al., Nature 470, 73 (2011)
Femtosecond x-ray nanocrystallography overcomes limitations of radiation damage
Beyond crystallography: A new world in structural sciences
•A very short and extremely bright coherent X-ray pulse can be used to outrun key damage processes and obtain a single diffraction pattern from a large macromolecule, a virus, or a cell without the need for crystalline periodicity.
•Mimivirus is the largest known virus, comparable in size to a small living cell. It is too big for structure determination by electron microscopy and it cannot be crystallised.
•The structure of the intact virus was recovered from the flash diffraction pattern alone.
•There was no measurable sample deterioration. •Death-rays: We expect high-resolution structures in such experiments with shorter and brighter photon pulses focused to a smaller area.
•Resolution can be further extended by averaging for samples available in multiple identical copies.
Single mimivirus particles intercepted and imaged with an X-ray laser
1000 nm
1
1
0
0
a
c
b
f g
200 nm1
0
d e
200 nm
Linac Coherent Light Source D. Wang et al., Science 324, 5931 (2009) • Linac Coherent Light Source M.M. Seibert, T. Ekeberg, F.R.N.C Maia et al., Nature 470, 78–81 (2011)
LCLS has experienced rapid user growth LCLS has experienced rapid user growth that is now limited by capacitythat is now limited by capacity
Oct.2009 May 2010 Oct.2010 May 2011
314 proposals 314 proposals submitted to date (through 2010)
1094 unique scientists 1094 unique scientists from from 25 countries 25 countries listed as collaborators on proposals submitted Sept 2008-June 2010
359 on359 on--site users site users worked at LCLS on scheduled proposals in FY2010
one in four proposals is approved due to capacity limits
LCLSLCLS--IIII
present LCLS
LCLS-2025
LCLS II (CD-1 2011, CD-4 2018)
soft x-rayhard x-ray
SLAC’s vision
soft x-rayhard x-ray
LCLS 2025
FEL R&Ds
• Higher peak power• Higher average power• Precise synchronize with lasers• Control x-ray polarization state• Produce attosecond x-ray pulses• …
• SASE FELs have excellent transverse coherence but lack full temporal coherence (due to shot noise startup)
• Temporal coherence can be drastically improved by seeding (external or self seeding)
SASE
seeded
HighHigh--Gain Harmonic Generation (HGHG)Gain Harmonic Generation (HGHG)
DDModulatorModulator RadiatorRadiator
11 hh== 11/h/h
seed seed laserlaser
to next to next stagestage
……...……...electronselectrons
L.L.--H. Yu, PRA44, 5178 (1991)H. Yu, PRA44, 5178 (1991)
Echo-Enabled Harmonic Generation (EEHG)G. Stupakov, PRL 102, 074801 (2009)
Separated energy bands Separated current spikesOne optical cycle
Very high harmonic bunching may be produced from external laserDemonstration experiments at SLAC and SINAP look promisingHigh harmonic bunching may seed a soft x-ray FELs (a few nm wavelength)
EEHG Results (2011.04)
330 335 340 345 350 355 3600.0
0.2
0.4
0.6
0.8
1.0
inte
nsity
(a.u
.)
wavelength (nm)
HGHG co-exist EEHG
0 5 10100
1000
10000
100000
1000000
1E7
pow
er (W
)z (m)
HGHG (Genesis) EEHG (Genesis) HGHG (experimental) EEHG (experimental)
Courtesy Z. Zhao, D. Wang
Power dist. after Power dist. after diamond crystaldiamond crystal
Monochromatic Monochromatic seed powerseed power
6 6 mm
Hard XHard X--ray Selfray Self--Seeding @ LCLS Seeding @ LCLS SelfSelf--seeding of 1seeding of 1-- m m ee pulse at 1.5 Å yields pulse at 1.5 Å yields 1010 44 BWBW with 20with 20--pC pC mode. mode. UndulatorUndulator taper provides taper provides 3030 brightness & 25 GWbrightness & 25 GW..PP. Emma (. Emma (SLAC), ASLAC), A. Zholents (ANL). Zholents (ANL)
FEL spectrum after the diamond crystal
Geloni, Kocharyan, Saldin (DESY)
1 GW1 GW ~25 GW~25 GW
WideWide--band band powerpower
Seeded FEL simulation (J. Wu)
LCLSLCLS--II II undulatorundulator
8.3 8.3 keVkeV ---- 1.5 Å 1.5 Å (13.5 (13.5 GeV)GeV)Quadratic tapering starts at Quadratic tapering starts at 20 20 m m (8.5%) (8.5%) from from 20 20 m to m to 200 200 mm4040--pC pC bunch bunch charge, 10 charge, 10 fsfs FWHM FWHM 0.20.2-- m m emittanceemittance
~1 ~1 TTWW
1.0 x 10 4
FWHMBW
J. Wu (SLAC)J. Wu (SLAC)
Seeding+Tapered Undulator TW FEL
Seeding start
Driven by development of accelerator science and technology, fourth-generation x-ray source based on FEL mechanism has become a reality
ConclusionsConclusions
X-ray FELs are opening up a new world of ultrasmall and ultrafast.
The high demands from the x-ray community will drive continuous growth of such sources and R&Ds.