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Synchrotron Radiation: A Future Retrospective. Symposium in Honor of Iran Thomas May 2003 Sunil K.Sinha UCSD/LANL. Where were we in 2003?. Over 8000 users at 4 DOE Light Sources. Methods of obtaining structures with X-Rays.

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synchrotron radiation a future retrospective

Synchrotron Radiation: A Future Retrospective

Symposium in Honor of Iran Thomas

May 2003

Sunil K.Sinha UCSD/LANL

where were we in 2003
Where were we in 2003?
  • Over 8000 users at 4 DOE Light Sources
methods of obtaining structures with x rays
Methods of obtaining structures with X-Rays
  • Scattering--beam can be large, but measures spatially and time-averaged snapshots of F.T. of instantaneous correlations ( no phase information)
  • EXAFS/NEXAFS/DAFS ( local order)
previous and current accomplishments
Previous and Current Accomplishments
  • Structure of Physisorbed and Chemisorbed Layers and 2D Phase Transitions.
  • Liquid Crystal Phases and Phase Transitions
  • Structure of Nanowires, Quantum Dots, Magnetic Dot and Hole Arrays.
  • Structures of Surface Reconstruction, Thin Films, Liquid Surfaces, Confined fluids
  • Magnetic multilayers and interfaces
slide6
New types of Charge, Spin and Orbital Ordering and Polarons in Complex Oxides: Manganites, Hi-Tc S/C, etc.
slide7

Imaging ---limited by size to which we can focus beam down to. Depends on Source Brilliance. Current limit 0.1 microns (Hard X-Rays), 35 nm (Soft X-Rays)

microbeam studies of residual strain in materials
Microbeam studies of Residual Strain in Materials
  • Schematic drawing of an x-ray microbeam experiment. Curved mirrors focus the synchrotron x rays down to a diameter of less than one micron on the sample. The microbeam penetrates each layer of the sample, and an area detector measures the directions of the scattered x rays. Here, the sample consists of a roll-textured nickel substrate covered with two epitaxial films: a buffer layer and a superconductor (YBCO). The detector image provides a grain-by-grain description of the atomic structure, orientation, and strain of each layer.
slide9

Schematic of a scanning x-ray nanoprobe using zone plate focusing.

Example----Element specific Imaging of Cells

what is exchange bias
What is exchange bias?

W.H. Meiklejohn, C.P. Bean, Phys Rev., 105, 904(1957).

J. Nogués, Ivan K. Schuller, J. of Magn. Magn. Mater.,192, 203 (1999).

slide11

bit line current produces easy axis field

Small sense current flows through bit

digit line current produces hard axis field

Isolation

Transistor

“OFF”

Isolation

Transistor

“ON”

  • MR=37%
  • Write at 4mA digit line and 3.2mA bit line current

“Read Mode”

“Write Mode”

random field domain state etc models

HCF

Random-field, domain state, etc., models

Super exchange (AF-coupling)

Frustrated super exchange (AF-coupling)

-1

+1

-’ve HE

+’ve HE

HCF

10nm

U. Nowak et. al., J. Magn. Magn. and Mater.,240, 243 (2002).

A.P. Malozemoff, J. Appl. Phys., 63, 3874 (1988).

slide14

Sample (1-10 mm) can be in air, water, or any low-absorption substance.

Detector system

f

scintillator

0.5 m

X-rays

CCD/video

Lens

f

x

x

Motion

stages

y

y

z

Experimental set-up

x ray photoemission spectroscopy
X-ray Photoemission Spectroscopy
  • Energy Bands and Fermi Surfaces of important materials --XPES/SPXPES
  • Symmetry of S/C Order Parameter and Electron Phonon coupling in Hi-Tc S/C
metal clusters and magnetism mott polarimeter detection
Metal Clusters and Magnetism Mott Polarimeter Detection
  • Measure the spin component parallel to the photon
  • Electron emitted perpendicularly to the photons, at 45 with respect to the storage ring plane.
ixs measures s q to 2mev resolution t ps
IXS measures S(q,) to ~2meV resolution (t≤ ps.)
  • Phonons in Liquids, Glasses, Quantum Crystals, Semiconductors, Metals
  • Electronic Excitations in metals, Hi-Tc Oxides, Spin-Peierls Chains, Mott Insulators
slide21

X-Ray Photon Correlation Spectroscopy (XPCS)--measures time scales greater than ms.Dynamics of Colloids, Liquid Surfaces

slide23

Microscope

50 nm resolution

Triggering pump

< 1 ps resolution

10 m

Time resolved probe

<100 ps resolution

J.Stohr, A.Scholl et al./SSRL

Photoconductive switch

  • Sample Deposition
  • sputter deposition (CXRO)
  • e-beam evaporation (PEEM)
  • Waveguide Structure
  • - photo-lithography, lift-off (UCB microlab)
  • Patterning
  • Focused Ion Beam (FIB) etching (NCEM)

Conducting wire

Magnetic Cells

Substrate: GaAs

Current

slide24

Ground plane

GaAs

waveguide

H

10 mm

Waveguide: 200 nm Cu Pattern: 20 nm Co90Fe10

Gradient image

Movie

H

XMCD image

Time

1 mm

x ray waveguides
X-Ray Waveguides
  • Capable of focusing hard X-Ray beam down to <50nm
  • In 1- or 2-D
geophysics and environmental science
Geophysics and Environmental Science
  • Diamond Anvil Cell coupled with small bright beams enabled studies of structure (phases).dynamics (Equation of State) of minerals in earth’s mantle and core; new phases of Hydrogen,ice, etc.
  • Fluorescence Microtomography yielded information on transfer of elements into environment, etc.
ultimate goal

Ultimate Goal

Can we image actual atoms (and maybe electrons) in real space and time?

why go lensless courtesy of janos kirz
Why go lensless?(Courtesy of Janos Kirz)
  • A technique for 3D imaging of 0.5 – 20 µm isolated objects
  • Too thick for EM (0.5 µm is practical upper limit)
  • Too thick for tomographic X-ray microscopy (depth of focus < 1 µm at 10 nm resolution for soft X-rays even if lenses become available)
  • Goals
  • <10 nm resolution (3D) in 1 - 10µm size biological specimens
  • (small frozen hydrated cell, organelle; see macromolecular aggregates)
    • Limitation: radiation damage!
  • 2 nm resolution in less sensitive nanostructures
  • (Inclusions, porosity, clusters, composite nanostructures, aerosols…)
  • eg: molecular sieves, catalysts, crack propagation
image reconstruction from the diffraction pattern
Image reconstruction from the diffraction pattern
  • Lenses do it, mirrors do it
  • – but they use the full complex amplitude!
  • Recording the diffraction intensity leads to the
  • “phase problem”!
  • Holographers do it – but they mix in a reference wave, need very high resolution detector or similar precision apparatus
  • Crystallographers do it – but they use MAD,
  • isomorphous replacement, or other tricks
  • (plus the amplification of many repeats)
slide30

“Oversampling”:

Non-crystals:

pattern continuous, can do finer sampling of intensity

Finer sampling; larger array;

smaller transform; “finite support”

(area around specimen must be clear!)

Miao thesis

reconstruction
Reconstruction

Equations can still not be solved analytically

Fienup iterative algorithm

Reciprocal space Real space

Impose

diffraction

magnitudes

Impose

finite

support

  • Positivity of electron density helps!

Miao thesis

slide32

DIFFRACTION IMAGING BY J. MIAO ET AL

  • 2-D reconstruction with Fienup-type algorithm
  • Both levels show because the depth of focus is sufficient
  • Resolution = 8 nm (new record)
  • From Miao, Ishikawa, Johnson, Anderson, Lai, Hodgson PRL Aug 2002
  • SEM image of a 3-D Ni microfabricated object with two levels 1 µm apart
  • Only top level shows to useful extent
  • Diffraction pattern taken at 2 Å wavelength at SPring 8

from Howells

slide33

MIAO ET AL 3-D RECONSTRUCTIONS

  • Miao et al 3-D reconstruction of the same object pair
  • a and b are sections through the image
  • cis 3-D density
  • Resolution = 55 nm
slide34

JCHS 7

Successful reconstruction of image from soft X-ray speckle alone.

SEM Image

X-ray reconstruction

50 nm diameter Gold Balls on transparent SiN membrane.

No “secondary image” was used

Approximate object boundary obtained from autocorrelation fn.

*How to make an isolated object ? Use AFM to remove unwanted balls.

He, Howells, Weierrstall, Spence Chapman, Marchesini et al. Phys Rev B In press. 03, Acta A.59, 143 (2003).

i k robinson et al gold nanocrystals
I.K. Robinson et al. gold nanocrystals

7.5 KeV beam at the APS

PRL 87, 195505 (2001)

slide37

Rapid development of accelerator technology, laser technology, X-Ray Physics and Scientific Knowledge will usher in a Revolution over the next 2 decades.

in the decades after 2003 upgraded rings lcls lux circe tjfel xfel
In the Decades after 2003….Upgraded Rings,LCLS,LUX,CIRCE,TJFELXFEL
  • Brilliances increase by 3-12 orders of magnitude
  • Femtosecond X-Ray pulses/attosecond pulses
  • Total transverse coherence
  • Photon degeneracies go from 0.4 to 1010
slide39

t=

t=0

Aluminum plasma

classical plasma

G

=1

G

=10

dense plasma

G

=100

high density

matter

1

-

4

-

2

2

4

10

10

10

10

Density (g/cm-3)

Femtochemistry

Nanoscale Dynamics

inCondensed matter

Atomic Physics

Plasma and Warm Dense Matter

Structural Studies on Single

Particles and Biomolecules

FEL Science/Technology

  • Presented to BESAC 10-Oct-2000

Science

Assessment

  • Critical Decision 0 approved
  • 13-June 2001

Program developed by international team of scientists working with accelerator and laser physics communities

“the beginning.... not the end”

single molecule imaging
Single molecule imaging?
  • Atomic resolution structures known for few mammalian membrane proteins!
  • Collect many single molecule diffraction patterns from fast x-ray pulses, and reconstruct?
  • Lysozyme explodes in ~50 fsec
  • R. Neutze et al., Nature406, 752 (2000)
slide41

Undulator

Seed laser

Ebeam

log (power)

Saturation

Distance

FEL Interaction

Electron slips backwards one wavefront per undulator period

Electrons are bunched under the influence of the light that they radiate.

The bunch dimensions are characteristic of the wavelength of the light.

slide42

100 mJ - 1 mJ

@ 800 nm

XUV @ 3 – 30 nm

h = 10-8 - 10-5

t

Propagation

Recombination

0

wXUV

x

tb

-Wb

Ionization

Energy

Laser electric field

High-Harmonic Generation

Noble Gas Jet (He, Ne, Ar, Kr)

slide43

High Gain Harmonic Generation

Method to reach short wavelength FEL output from longer wavelength input seed laser.

Input seed at w0 overlaps electron beam in energy modulator undulator.

Energy modulation is converted to spatial bunching in chicane magnets.

Electron beam radiates coherently at w3 in long radiator undulator.

Radiator is tuned to w3.

Modulator is tuned to w0.

Electron beam develops energy modulation at w0.

3rd harmonic bunching is optimized in chicane.

slide44

Output at 3w0 seeds 2nd stage

Output at 9w0 seeds 3rd stage

Final output at 27w0

Input seed w0

3rd stage

1st stage

2nd stage

Cascaded HGHG

  • Number of stages and harmonic of each to be optimized during study.
  • Factor of 10 – 30 in wavelength is reasonable without additional acceleration between stages.
  • Seed longer wavelength (100 – 10 nm) beamlines with ~200 nm harmonic from synchronized Ti:Sapp laser.
  • Seed shorter wavelength (10 – 0.3 nm) beamlines with HHG pulses.
slide45

Main oscillator

Fiber link synchronization

UV Hall

X-ray Hall

Seed laser

Pump laser

Seed laser

Pump laser

Undulators

100 nm

Undulators

30 nm

1 nm

Injector laser

10 nm

0.3 nm

SC Linac

0.3 nm

SC Linac

0.1 nm

1 GeV

2 GeV

4 GeV

10 nm

Upgrade: 0.1 nm at 8 GeV

3 nm

1 nm

Undulators

Seed laser

Pump laser

Nanometer Hall

MIT X-ray Laser Concept

slide46

HISTORY of ADVANCES in ULTRASHORT PULSE DURATION

rotation

10ps

Nd:glass

Nd:YLF

Nd:Y

AG

Diode

S-P Dye

Dye

1ps

vibration

SOLID-STATE

CW Dye

REVOLUTION

SHORTEST PULSE DURATION

Color

Center

100fs

Cr:LiS(C)AF

CP

M

Dye

Er:fiber

DYE LASER

Cr:YAG

Nd:fiber

BREAKTHROUGHS

Cr:forsterite

w/Compression

10fs

Ti:sapphire

electronic

“new” era: attophysics

1fs

1965

1970 1975

1980 1985

1990 1995

2000

2005

Vienna

YEA

R

Saclay/FOM

100as

First laser

atomic unit of time  24 as

First passive modelocking

10as

1970 1975

1980 1985

1990 1995

2000

2005

YEAR

slide47

BREAKING THE fs BARRIER

100 nm

(50 THz)

100 as  5,000 THz !!!

time 

  • Uncertainty Principle: t   need bandwidth !!
  • Control phases of field e.g. mode-locked
  • Attosecond metrology
slide48

MEASURING ULTRASHORT PULSES

delay line

  • autocorrelation: determine I(t).

A()

Prism

(x)

PMT

2

time

BS

(2)

  • Criteria:
    • nonlinear media, e.g. (2), (3)
    • adequate peak power
  • NL interferometric techniques: complete determination of E,.FROG, TAPOLE, SPIDER, etc.
  • These techniques are applicable throughout the visible and near IR and UV.
slide49

ATTOSECOND SIDEBAND CROSS-CORRELATION

HHG photoionization

HHG + fundamental

  • sidebands are XUV+ocross-correlation.
  • scan delay between XUV and o .
  • amplitude or energy modulation.
  • analysis is model dependent.

H17

e energy

H17

e energy

electrons

electrons

H13

H13

gnd

gnd

slide50

TRAIN of ATTOSECOND PULSES

sideband amplitude

-4

-2

0

1

delay (fs)

P. M. Paul et al., Science 292, 1689 (2001)

slide51

TRAIN of ATTOSECOND PULSES

P. M. Paul et al., Science 292, 1689 (2001)

  • analysis shows the formation of a train of 250 as pulses.
slide52

GENERATION of a ‘SINGLE’ ASEC PULSE

M. Hentschel et al., Nature 414, 509 (2001)

these enabled
These enabled:
  • Creation and Study of Dense Warm Plasmas
  • Multi-photoionization studies, “Hollow Atoms”
  • Above Threshold Ionization (ATI) Studies in X-ray regime
  • Diffraction, EXAFS, PES, Pump-Probe Studies of Clusters.
  • Photodissociation of molecules
  • Laser Excited, Aligned or Oriented Atoms
  • EXAFS,NEXAFS, Photoemission on fs timescales.
so maybe we will have
So (maybe) we will have ….
  • Completely understood High-Temperature superconductivity and strongly correlated systems. How gaps evolve with time at phase transitions, how inhomogeneous phases evolve, etc.
  • Understood the relation between exchange bias, magnetotransport and interface properties, understood dynamics of domain switching, spatial and dynamical behavior of spin injection into semiconductors.
  • Understood Glasses and the Glass Transition
  • Mapped out energy bands, collective electronic and spin excitations in solids.
  • Solved the detailed structure of non-crystallizable proteins, and understood the relations between structure, dynamics and function; understood Protein folding.
slide55
and
  • Understood in exquisite detail what the atoms do during structural phase transitions,shock wave induced phase changes, pressure-induced amorphization, etc.--strain propagation, bond stretching, bond-breaking, transient structures, melting and recrystallization, etc.
  • Characterize non-linear excitations in solids
  • Create, and test theories of warm dense plasmas
slide56
and
  • Characterize and make 2D and 3D nanostructures with X-ray nanolithography
  • Able to exercise quantum control over chemical reactions, excited states of atoms nad molecules
  • Trap atoms and create BE condensates, “crystals”, etc. on nm lengthscales and study their interactions and study ultrafast perturbations