David Fritz [email protected] LCLS FAC Meeting Oct. 30, 2007 1 X-ray Pump-Probe Instrument...
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Transcript of David Fritz [email protected] LCLS FAC Meeting Oct. 30, 2007 1 X-ray Pump-Probe Instrument...
David [email protected]
LCLS FAC MeetingOct. 30, 2007 1
X-ray Pump-Probe Instrument David Fritz
X-ray Pump-Probe Instrument David Fritz
Instrument OverviewInstrument LayoutSystem Description
X-ray Optics &DiagnosticsSample EnvironmentsDetectorsLaser System
FEL/Pump Laser Timing SystemTechnical IssuesSummary
Instrument OverviewInstrument LayoutSystem Description
X-ray Optics &DiagnosticsSample EnvironmentsDetectorsLaser System
FEL/Pump Laser Timing SystemTechnical IssuesSummary
David [email protected]
LCLS FAC MeetingOct. 30, 2007 2
X-ray Pump-Probe ScienceX-ray Pump-Probe Science
Phase TransitionsOrder / Disorder Metal/Insulator Phonon Dynamics
Charge Transfer Reactions
PhotosynthesisPhotovoltaicsVision
Photoactive Proteins
Phase TransitionsOrder / Disorder Metal/Insulator Phonon Dynamics
Charge Transfer Reactions
PhotosynthesisPhotovoltaicsVision
Photoactive Proteins
photo-excitation
Stampfli and Bennemann Phys. Rev. B 49, 7299 (1994)
photo-excitation
David [email protected]
LCLS FAC MeetingOct. 30, 2007 3
Ultrafast Hard X-ray Sources to DateUltrafast Hard X-ray Sources to Date
3rd Generation Synchrotrons (APS)~ 1 x 10 9 photons/second coincident with a 1 kHz Laser100 ps pulse duration
Slicing Source~ 1 x 10 6 photons/second coincident with a 1 kHz Laser100 fs pulse duration
Laser Plasma Source~ 1 x 10 5 photons/second collected at 10 Hz300 fs pulse duration
Sub-Picosecond Pulse Source~ 1 x 10 7 photons/second coincident with a 10 Hz Laser100 fs pulse duration
3rd Generation Synchrotrons (APS)~ 1 x 10 9 photons/second coincident with a 1 kHz Laser100 ps pulse duration
Slicing Source~ 1 x 10 6 photons/second coincident with a 1 kHz Laser100 fs pulse duration
Laser Plasma Source~ 1 x 10 5 photons/second collected at 10 Hz300 fs pulse duration
Sub-Picosecond Pulse Source~ 1 x 10 7 photons/second coincident with a 10 Hz Laser100 fs pulse duration
David [email protected]
LCLS FAC MeetingOct. 30, 2007 4
Ultrafast X-ray Science to DateUltrafast X-ray Science to Date
Limited to slow processes ( > 100 ps)or
X-ray diffraction from single crystals
Limited to slow processes ( > 100 ps)or
X-ray diffraction from single crystals
Large Amplitude Coherent Phonons
-500 0 500 1000 1500 2000
0.2
0.4
0.6
0.8
1.0
t (fs)
norm
aliz
ed d
iffr
acti
on in
tens
ity (220)
(111)
Non-thermal Melting of Semiconductors
20 minute acquisition at SPPSSingle Shot at SPPS
David [email protected]
LCLS FAC MeetingOct. 30, 2007 5
XPP Instrument ScopeXPP Instrument Scope
X-ray Wavelength and Bandwidth
Sample EnvironmentScattering
TechniqueExcitation Laser
Parameters
Fundamental Monochromatic
Fundamental 3rd Harmonic Monochromatic 3rd
Harmonic
Room Press. & Room Temp
Temperature Controlled Cryostat
Liquid Vacuum
Wide Angle Scattering
Small Angle Scattering
Emission
Med. Energy (2 mJ fund.)
Fundamental (800 nm) 2nd Harmonic (400 nm) 3rd Harmonic (266 nm) OPA
High Energy (20 mJ fund.)
Fundamental (800 nm) 2nd Harmonic (400 nm) 3rd Harmonic (266 nm)
Versatility is key to the instrument successVersatility is key to the instrument success
Instrument will operate in the 6-25 keV photon energy range
David [email protected]
LCLS FAC MeetingOct. 30, 2007 6
Instrument SpecificationsInstrument Specifications
Secondary Slits
Wide Angle Stage
Small Angle Stage
Photon Shutter
Focusing Lenses
Photon Shutter
Monochromator
Photon Shutter
Item Purpose Specification
Large Offset Monochromator
Multiplex FEL radiation,Narrow FEL spectrum
600 mm offset,≤ 10-4 spectral bandwidth
Harmonic Rejection Mirrors
Filter 3rd Harmonic Radiation
105 : 1 contrast ratio< 0.5 nm surface roughness
Slits/AperturesBeam definition, Beam halo cleaning
0.1 um stability, 1 um repeatability
Attenuators Control incident x-ray fluxVariable, up to 107 reduction at 1.5 Å
DiagnosticsIntensity Monitor, Position Monitor
0.1% relative intensity measurement,
< 5% incident x-ray attenuation
Be Focusing Lenses
Increase incident x-ray flux
2-10 mm, 40-60 mm spot size at 1.5 Å,
2-10 mm spot size at 0.5 Å
Laser System Photoexcitation of samplesUltrafast pulse duration (<50 fs), Up to 20 mJ pulse energy at 800 nm, 120 Hz
X-ray Diffractometer
Sample orientationKappa diffractometer,
Platform diffractometer
Wide Angle Detector Stage
Move the detector in reciprocal space
Spherical detector motion at a 10-150 cm radius
Small Angle Detector Stage
Collect SAXS patterns2.5, 5, and 10 m Sample-to-detector distance, 0.5 m horizontal detector motion
2D DetectorProvide 2D pixelated detection capability
1024 x1024 pixels, 120 Hz frame/s, dynamic range >103, single-photon sensitivity, pixel size 90x90 mm2
Mirror System
Primary Slits
Diagnostics
Attenuators
Diagnostics
Diffractometer
NE
H H
utch
3
Diagnostics
Diagnostics
Laser Port
FE
E
Diagnostics
David [email protected]
LCLS FAC MeetingOct. 30, 2007 7
XPP Instrument LocationXPP Instrument Location
XCS
AMO(LCLS)
CXI
XPPEndstation
David [email protected]
LCLS FAC MeetingOct. 30, 2007 8
X-ray Pump-Probe Instrument
OffsetMonochromator
Laser System(Fundamental)
X-rayDiffractometer& BNL Detector
WavelengthConversion
Small AngleScattering
X-ray Opticsand Diagnostics
David [email protected]
LCLS FAC MeetingOct. 30, 2007 9
X-ray Optics – Offset MonochromatorX-ray Optics – Offset Monochromator
Double crystal offset monochromatorNarrows x-ray spectrum for resonant scattering experimentsMultiplexes LCLS beam (mono. beam, diagnostic beam)
Double crystal offset monochromatorNarrows x-ray spectrum for resonant scattering experimentsMultiplexes LCLS beam (mono. beam, diagnostic beam)
Parameter Value
Energy Range 6 – 24 keV
Horizontal Offset 600 mm
Scattering Angle 140 - 500
Accuracy 0.02 arcsec
χ Accuracy 4 arcsec
Scattering Angles (2 theta)
1.5 Å 0.5 Å
Silicon 111 27.6° -
Silicon 220 45.8° 14.9°
Diamond 111 42.5° 13.9°
Diamond 220 - 22.8°
David [email protected]
LCLS FAC MeetingOct. 30, 2007 10
X-ray Optics - AttenuatorsX-ray Optics - Attenuators
AttenuatorsVariable, up to 10 7 reduction at 8.3 keVCoherence preservingHigh damage threshold
AttenuatorsVariable, up to 10 7 reduction at 8.3 keVCoherence preservingHigh damage threshold
David [email protected]
LCLS FAC MeetingOct. 30, 2007 11
X-ray Optics – Slit SystemsX-ray Optics – Slit Systems
Slit systemsVariable horizontal and vertical gap from 5 μm – 5 mmCan withstand full LCLS flux – unfocusedMinimize background scatter from blades
Slit systemsVariable horizontal and vertical gap from 5 μm – 5 mmCan withstand full LCLS flux – unfocusedMinimize background scatter from blades
D. Le Bolloc’h et al., J. Synchrotron Rad., 9, 258-265 (2002).
David [email protected]
LCLS FAC MeetingOct. 30, 2007 12
X-ray Optics - Be Focusing LensesX-ray Optics - Be Focusing Lenses
Beryllium CRL> 40% throughput
Positioning resolution and repeatability to 1 µmZ translation to vary spot size
Beryllium CRL> 40% throughput
Positioning resolution and repeatability to 1 µmZ translation to vary spot size
B. Lengeler et al., J. Synchrotron Rad., 6, 1153-1167 (1999).
David [email protected]
LCLS FAC MeetingOct. 30, 2007 13
X-ray Optics – Harmonic Rejection MirrorsX-ray Optics – Harmonic Rejection Mirrors
Harmonic Rejection Mirror System> 80% throughput
10 5 : 1 contrast ratio (10 7 : 1 overall)
Harmonic Rejection Mirror System> 80% throughput
10 5 : 1 contrast ratio (10 7 : 1 overall)
10-4
10-5
10-2
10-6
10-3
David [email protected]
LCLS FAC MeetingOct. 30, 2007 14
Kappa DiffractometerKappa Diffractometer
Kappa X-ray DiffractometerOperate in both direct and monochromatic beamLarge reciprocal space accessGas stream temperature control
Kappa X-ray DiffractometerOperate in both direct and monochromatic beamLarge reciprocal space accessGas stream temperature control
η φ
κ
α = 50º
KinematicMount
XY Table
μ
ν
δ x
David [email protected]
LCLS FAC MeetingOct. 30, 2007 15
Platform DiffractometerPlatform Diffractometer
Platform X-ray DiffractometerOperate in both direct and monochromatic beamAccommodates large sample environments (Cryostats, vacuum chambers, etc…)
Platform X-ray DiffractometerOperate in both direct and monochromatic beamAccommodates large sample environments (Cryostats, vacuum chambers, etc…)
χ
x trans
ω
z trans
y trans
KinematicMount
XY Table
μ
ν
δ
David [email protected]
LCLS FAC MeetingOct. 30, 2007 16
Emission SpectroscopyEmission Spectroscopy
X-ray Emission Spectrometer~ 50 eV dynamic range~ 0.1 eV resolutionLarge collection solid angle
X-ray Emission Spectrometer~ 50 eV dynamic range~ 0.1 eV resolutionLarge collection solid angle
XAMPS
XY Table
μ
ν
δ
sample
PSD
analyzers
vertical cut top view
beam
analyzers
spectrum
David [email protected]
LCLS FAC MeetingOct. 30, 2007 17
Small Angle ScatteringSmall Angle Scattering
SAXS Capability2.5, 5, and 10 m sample-to-detector distance10 µrad angular resolution with XAMPS detector (10 m)Operate in both direct and monochromatic beam
SAXS Capability2.5, 5, and 10 m sample-to-detector distance10 µrad angular resolution with XAMPS detector (10 m)Operate in both direct and monochromatic beam
David [email protected]
LCLS FAC MeetingOct. 30, 2007 18
2D Detectors2D Detectors
2D detector (BNL)1024 x 1024 pixels 90 micron pixel sizeHigh Detector Quantum Efficiency (DQE)10 4 dynamic range at 8 keV120 Hz Readout Rate
2D detector (BNL)1024 x 1024 pixels 90 micron pixel sizeHigh Detector Quantum Efficiency (DQE)10 4 dynamic range at 8 keV120 Hz Readout Rate
David [email protected]
LCLS FAC MeetingOct. 30, 2007 20
Laser SystemLaser System
Ti:Sapphire Oscillator & Power Amplifiers
Compressor, OPA, Harmonic Generation, Delay Stage
David [email protected]
LCLS FAC MeetingOct. 30, 2007 21
Laser SystemLaser System
Laser DiagnosticsTemporal and spectral characterization
Grenouille – Real time pulse duration, spectrum3rd Order Correlator – Contrast ratio
Energy characterizationPer pulse Joule meter, 120 Hz, 1% accuracy
Spatial characterizationProfile monitor at a “virtual” sample, 5 μm resolution
Laser DiagnosticsTemporal and spectral characterization
Grenouille – Real time pulse duration, spectrum3rd Order Correlator – Contrast ratio
Energy characterizationPer pulse Joule meter, 120 Hz, 1% accuracy
Spatial characterizationProfile monitor at a “virtual” sample, 5 μm resolution
David [email protected]
LCLS FAC MeetingOct. 30, 2007 22
X-ray DiagnosticsX-ray Diagnostics
Transmissive Intensity Monitor> 95 % TransmissionRelative accuracy < 0.1%
Flourescent ScreeensDiodes
Transmissive Intensity Monitor> 95 % TransmissionRelative accuracy < 0.1%
Flourescent ScreeensDiodes
David [email protected]
LCLS FAC MeetingOct. 30, 2007 23
AcceleratingElements
ExperimentalPump Laser
Electron Gun
Master Clock
RF Distribution
Network
Laser/FEL TimingLaser/FEL Timing
Sources of Short Term JitterE-beam phase to RF phase jitter
Electron beam energy jitter + dispersive electron opticsEnd station laser phase to RF Phase
~ 1 ps limit
Sources of Short Term JitterE-beam phase to RF phase jitter
Electron beam energy jitter + dispersive electron opticsEnd station laser phase to RF Phase
~ 1 ps limit
David [email protected]
LCLS FAC MeetingOct. 30, 2007 24
Traditional Pump-probeTraditional Pump-probe
Delay will be achieved by optical delay and/or RF phase shiftResolution limited by LCLS/laser jitter ~ 1 ps limit
Delay will be achieved by optical delay and/or RF phase shiftResolution limited by LCLS/laser jitter ~ 1 ps limit
C. W. Siders
David [email protected]
LCLS FAC MeetingOct. 30, 2007 25
Single Shot Pump-ProbeSingle Shot Pump-Probe
time (fs)di
ffra
cted
in
tens
ity
Limited to X-ray diffractionNeed ‘large’ effectsImaging resolution affects temporal resolution
Limited to X-ray diffractionNeed ‘large’ effectsImaging resolution affects temporal resolution
A. M. Lindenberg et al., Science, 308, 392 (2005).
David [email protected]
LCLS FAC MeetingOct. 30, 2007 26
Laser/FEL TimingLaser/FEL Timing
Electro-optic Sampling
Laser
Pump-probe
Laser
LTU NEH
Gun Laser
Sector 20
Stabilized Fiber Optic RF Distribution (10 fs)
LBNL
Electro-optic SamplingEnhanced Temporal Resolution (~ 100 fs)
Limited by our ability to phase lock the lasers to the RF backboneLimited by Intra-bunch SASE jitter
Electro-optic SamplingEnhanced Temporal Resolution (~ 100 fs)
Limited by our ability to phase lock the lasers to the RF backboneLimited by Intra-bunch SASE jitter
David [email protected]
LCLS FAC MeetingOct. 30, 2007 27
Non-sequential SamplingNon-sequential Sampling
100 consecutive shots
Single shot, Lorentzian fit
Diagnostic required to measure LCLS/laser timingEOS demonstrated at SPPS
Diagnostic required to measure LCLS/laser timingEOS demonstrated at SPPS
David [email protected]
LCLS FAC MeetingOct. 30, 2007 28
Laser/FEL TimingLaser/FEL Timing
Diagnostic Beam for Direct Timing MeasurementPermits destructive x-ray timing measurement in hutchSame excitation laser can be used
Diagnostic Beam for Direct Timing MeasurementPermits destructive x-ray timing measurement in hutchSame excitation laser can be used
600mm
Transmitted Beam85%
8keV
Diagnostic Beam1.3%
Mono. Beam2.5%
David [email protected]
LCLS FAC MeetingOct. 30, 2007 29
Technical IssuesTechnical Issues
1. X-ray/Laser Timing Below 100 fs2. Flexible Diffractometer Design
- Kappa + Platform
3. Thin Monochromator Crystals- Diamond vs. Thin Silicon - (Absorption, Damage vs. Quality)
4. Monochromator Precision Motion- 200 nRad motion & stability
5. Rejecting Fundamental in 3rd Harmonic Operation
1. X-ray/Laser Timing Below 100 fs2. Flexible Diffractometer Design
- Kappa + Platform
3. Thin Monochromator Crystals- Diamond vs. Thin Silicon - (Absorption, Damage vs. Quality)
4. Monochromator Precision Motion- 200 nRad motion & stability
5. Rejecting Fundamental in 3rd Harmonic Operation
David [email protected]
LCLS FAC MeetingOct. 30, 2007 30
SummarySummary
Instrument design emphasizes flexibilityX-ray scattering techniques
WAXSSAXSEmission spectroscopy
X-ray optics can tailor FEL parameters for users Many sample environments are accommodated
VacuumLow temperature (cryostat, cryostream)Samples in solution
Versatile laser system
Instrument design emphasizes flexibilityX-ray scattering techniques
WAXSSAXSEmission spectroscopy
X-ray optics can tailor FEL parameters for users Many sample environments are accommodated
VacuumLow temperature (cryostat, cryostream)Samples in solution
Versatile laser system
David [email protected]
LCLS FAC MeetingOct. 30, 2007 31
Non-sequential SamplingNon-sequential Sampling
D. M. Fritz et al., Science, 315, 633 (2007).A. L. Cavalieri et al., Phys. Rev. Lett., 94, 114801 (2005).