1March 2012

Will Size Define a New Generation of Light Sources?

David E. Moncton

Future Light Sources Conference

JLab

March 5, 2012

2March 2012

Summary

• The most substantial societal impact of x-rays has come from small scale sources—x-ray tubes (14 Nobel prizes)

• Synchrotron radiation has made enormous impact in two ways– Science accomplished (4 Nobel prizes)

– Development of extremely powerful methods based on high brilliance

made possible by incoherent emission from relativistic beams

• X-ray free-electron lasers will also have enormous impact– Access the fs timescale for the first time with significant flux

– Enable the development of methods exploiting the high peak brilliance made possible by coherent electron emission from relativistic beams

• Future machine beyond the ultimate single-mode FELs will combine the features of these three generations of sources– Small scale, relativistic e-beams, and coherent emission.

3March 2012

X-ray Science Driven by Beam Brilliance

X-ray Lasers

SynchrotronRadiation

X-ray Tubes

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4March 2012

Roentgen’s X-ray Tubes circa 1895

5March 2012

The Modern X-ray Tube

Rigaku FR-E flux on crystal ~ 4 x 109 ph/sec

6March 2012

Spiral CT (Computed Tomography) Imaging

Note: We now know that much better images can be obtained by phase contrast methods, but are not possible with the cathode ray tube

7March 2012

Nobel Prizes for X-ray Research

8March 2012

First Reference Proposing Use of Synchrotron X-rays

9March 2012

Radiation from Charged Particles (1952)

10March 2012

X-ray Science Driven by Beam Brilliance

X-ray Lasers

SynchrotronRadiation

X-ray Tubes

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11March 2012

APS

Kappa Goniostat, ROBAC,Q315 detector

10 Tb NSF

Storage

Thousands of Protein Structures from One APS Beamline

The Structural Biology Center

12March 2012

Nobel Prizes for Synchrotron X-ray Research

1997 ATP-synthase structure (Boyer, Walker)

2003 Ion channels (Agre, MacKinnon)

2006 Eukaryotic transcription (Kornberg)

2009 Ribosime structure (Ramakrishnan, Steitz, Yonath)

13March 2012

X-ray Science Driven by Beam Brilliance

X-ray Lasers

SynchrotronRadiation

X-ray Tubes

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14March 2012

New Facilities Based on SASE Radiation

SLAC Stanford

15March 2012

A Tutorial on Peak Brilliance

Peak Brilliance = # photons/xxyy t E

2.3 x 1021/ (nm)

•New scientific frontiers require access to the spatial and temporal regimes where new properties emerge that are out of reach with 3rd gen sources

•This challenge requires the highest collimation, the smallest beam size, the shortest pulses and the best energy resolution—often simultaneously

•The denominator is the phase space volume of the source which can be as small as the uncertainty principle allows—one photon mode

•Therefore peak brilliance is a direct measure of the # photons in the most highly occupied mode—aka photon degeneracy

•To convert from peak brilliance to photon degeneracy divide by

16March 2012

Peak Brilliance

Example—The Advanced Photon Source with peak brilliance about 1023 at0.1 nm

2.3 x 1021/ (nm)Degeneracy =

In other words the most highly occupied mode has, on average, a 4 percent chance of having one photon in it.

17March 2012

Peak Brilliance

Example—The LCLSwith peak brilliance about 1034 at0.1 nm

2.3 x 1021/ (nm)Degeneracy =

x

What is the difference between sources with degeneracy of 109 and those sources with degeneracy from .01—100?

It is the fundamentally different process producing the radiation– coherent vs incoherent emission, laser vs. light bulb

Ring sources produce photons one electron at a time, proportional to the number N of electrons

Lasing is a coherent electron process proportional to N2

18March 2012

19March 2012

Two Key Questions

Are SASE sources the ultimate in x-ray technology?

Are billion dollar central facilities the only option?

While SASE sources benefit from exponential gain, the resulting beam has poor quality compared to a single mode optical laser.

No

NoAdvances in accelerator, laser, and nano technology offer opportunities to build high performance x-ray sources of the scale of a university laboratory

20March 2012

t (fs) (%)

The SASE radiation is powerful, but noisy!

Solution: Impose a strong coherent modulation with an external laser source

SASE Amplifies Random Electron Density Modulations

21March 2012

A Transform-Limited X-ray Pulse

Transverse phase space

x , y ~ 50 microns

kx , ky ~ 10-5 nm-1

Longitudinal phase space

t ~ 1fs - 1ps ~ 2eV - 2meV

A 1 milli-Joule pulse contains 5.0 x 1011 12 keV photons

x kx = ½

y ky = ½

t = ½

Peak brilliance = 1036 3rd Gen: 1025

• Satisfies the Uncertainty Principle in all dimensions

22March 2012

Brookhaven Laser Seeding Demonstration

Buncher

e-

Laser

800 nm

Modulator

266 nm

output

Radiator

•Suppressed SASE noise

•Amplified coherent signal

•Narrowed bandwidth

•Shifted wavelength

High Gain Harmonic Generation (HGHG)

SASE x105

HGHG

L.H. Yu et al., Phys. Rev. Lett. 91, 74801 (2003).

23March 2012

X-ray Science Driven by Beam Brilliance

X-ray Lasers

SynchrotronRadiation

X-ray Tubes

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24March 2012

Compact X-ray Sources

?

• There is a growing and urgent need to fill the large gap between laboratory x-ray tubes, and large central facilities.

• At nano-centers such as EMSL that are not at synchrotron sources, advanced x-ray capability is the most important missing probe of matter.

• Advances in accelerator and laser technology make high-brilliance, short pulses sources possible and affordable.

25March 2012

The Technical Opportunity

e-

L

X

• Normal Compton Scattering the photon has higher energy than the electron

• The inverse process has the Thomson cross-section when X e

• The scattered photon satisfies the undulator equation with period L/2 for head-on collisions

energy = e= me

X = L(1+22)

42

• Therefore, the x-ray energy decreases by a factor of 2 at an angle of 1/

Ee

• Head-on collision between a relativistic electron and a photon

Inverse Compton Scattering

26March 2012

Lyncean Technologies Compact Source Concept

Parameters of SourceAverage flux 109 photons/secSource size 50 microns

Courtesy of Ron Ruth

27March 2012

MIT Inverse Compton Scattering Concept

28March 2012

(mrad)

Ph

oto

n E

ne

rgy

(k

eV

)

-40 -20 0 20 40

2

4

6

8

10

12

10

0.1

0.01

100photons/mrad2/eV

1

Note: Plane Perpendicular to Laser Polarization

Normalized emittance = 0.3 m

photons/mrad2/eV

(mrad)

Ph

oto

n E

ner

gy

(keV

)

-40 -20 0 20 40

2

4

6

8

10

1210

0.1

0.01

1

Normalized emittance = 1.0 m

Full Calculations of the Photon Spectrum

29March 2012

dx/dz (mrad)

dy/

dz

(mra

d)

-8 -6 -4 -2 0 2 4 6 8

-8

-6

-4

-2

0

2

4

6

8

1000

2000

3000

4000

5000

6000

7000

8000

Intensity Profile of 12 keV X-rays with 0.1% bw

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

-9 -7 -5 -3 -1 1 3 5 7 9

y (mrad)In

ten

sit

y (

ke

V/m

rad

^2

)

~1012 photons/sec @ 100 MHz in 0.1% BW

Calculations by Winthrop Brown, MIT LL

30March 2012

Conceptual Multi-User Facility based on ICS

Coherent enhancement cavity with Q=1000 giving 1 MW cavity power

1 kW cryo-cooled Yb:YAG drive laser

Superconducting RF photoinjector

X-ray beamline 2

Inverse Compton scattering

X-ray beamline 3

X-ray beamline 4

X-ray beamline 1

Electron beam of 1-100 mA average current at 10-30 MeV

10 kW beam dump

6 m

8 m

Superconducting RF Linac

31March 2012

ParameterHigh average

fluxSingle-shot

Tunable monochromatic photon energy [keV] 3 – 12 3 – 12

Pulse length [ps] 0.1 – 2 1 – 10

Flux per shot [photons] 5 x 106 1 x 1010

Repetition rate [Hz] 108 1-10

Average flux [photons/sec] 5 x 1014 1 x 1011

FWHM bandwidth [%] 25 25

On-axis bandwidth [%] 1 2

Source RMS divergence [mrad] 1 5

Source RMS size [mm] 0.002 0.006

Peak brightness [photons/(sec mm2 mrad2 0.1%bw)]

1 x 1020 6 x 1022

Average brightness [photons/(sec mm2 mrad2)] 3 x 1015 6 x 1011

X-ray Source Parameters

32March 2012

X-ray Science Driven by Beam Brilliance

X-ray Lasers

SynchrotronRadiation

X-ray Tubes

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Incoherent ICS

Coherent ICS

33March 2012

Coherent ICS

• How can coherent emission be achieved to boost ICS performance?

Answer: Maybe—by structuring the electron beam, not by laser seeding, but by using a structured nanocathode as a electron source, after T. Akinwande, MIT.

34March 2012

Coherent ICS

It appears possible to manipulate these structured bunches in magnet arrays to compress, rotate, and exchange transverse and longitudinal coordinates, resulting in a sub nm periodic structure which will then coherently emit a hard x-ray beam. See talk by Bill Graves on Wednesday

35March 2012

Protein Crystallography

Small Crystals with Fixed Wavelength and MAD

• Goal: Achieve ICS images with 10 m crystals of equal or better quality compared to rotating anode (Rigaku FR-E) with 100 m crystals.

│← 160 mm →│

Multilayer Osmic

Condenser

30 µ

2 mm

Multilayer Osmic

Collimator

10 µ

Asymmetric Ge (111)

or Si (111)

‹ 100 µrad 3.3 mrad

10 mrad

20 cm

60 cm

Fixed Wavelength:MAD:

Ge(111); E = 16 eV; R = 67%

Si (111); E = 7 eV; R = 80%

36March 2012

Medical Applications

• Medical Imaging—Improved Absorption Images– Current radiographs use 5-75 keV Bremstahlung spectrum– Low energy range causes skin dose, no contrast– High portion cause tissue dose with low contrast– Only the range of energies around 30 keV useful– ICS spectrum is ideal at 30 keV with 5-15% bandwidth– Image quality improved and dose reduced– We would establish collaboration with local radiologists to

further study these factors in detail

• Medical Imaging/Therapy—Tuning to specific wavelengths– Iodine contrast agent for blood imaging– Gd or Pt based cancer therapy

37March 2012

Medical Applications

• Medical Imaging—Phase Contrast Method– Few micron circular source is ideal

– Many milli-radian divergence illuminates large objects in short distance

– Few percent bandwidth can be fully utilized and presents no limitation

– Would improve medical imaging for soft tissue while reducing dose

– Could also utilize the single-shot mode for time-resolved images

– Simplest approach requires no optics

– But optics could reduce spot size, increase coherence, and increase illuminated area

38March 2012

Ultrafast Science Opportunities

• Pico-second Science– Synchrotron sources have 50-100 ps pulse lengths

– ICS source may have pulse lengths down to 100 fs

– At 1 ps the single-shot flux could be >109 photons in a 6% bandwidth

– Large bandwidths are appropriate for Laue method as pioneered by Wulff and co-workers at ESRF

– ICS could be run in a kHz mode for repetitive experiments

– Both diffraction and PC imaging modes possible

– Flux exceeds plasma sources by many orders of magnitude

– Flux exceeds storage ring pulse chopping schemes

– Would be a stepping stone to the big FELs

39March 2012

Kirk Clark, Novartis Institutes for Biomedical Research

• Structural Biology is an integral component of many drug discovery programs.

– Guides medicinal chemistry efforts; turn-around time is critical

– Insight into protein function; novel structures benefit from tunable x-rays

– Epitope mapping for antibodies; rapid structures (even low resolution) valuable

• Benefits of bright, local x-ray source

– Time. Quick feedback on quality of small crystals and/or final datasets.

• Small crystals are more readily obtained with less reagents

• Reduced opportunity costs by avoiding needless improvements to good crystals.

– Facilitate expanding structural biology to integral membrane proteins.

– Costs. Reduced travel costs (currently traveling to Chicago/Zurich every 3 to 4 weeks), proprietary fees, access fees.

39

Novartis

40March 2012

Wyeth

41March 2012

National High Magnetic Field Laboratory

42March 2012

NIST Gaithersburg Campus

NCNR

AXF

CNSTSIRCUS

SURF III

Neutron Research

Nanoscale Science & Technology

Ultraviolet Synchrotron

Radiation Laser Spectroscopy

Advanced X-ray Facility

43March 2012

LC2RMF = Laboratory of analytical chemistry and scientific imaging located in the Louvre

Objectives: Research, expertise and support for curators and conservators thanks to physico-chemical analyses.

Ø Necessity of non destructive testing with high sensitivity because the studied materials are very complex

1989: Installation of the accelerator AGLAE in the Louvre = ion beam analysis with an external microbeam (elemental analysis, direct on the artifacts)

1997: Development of synchrotron radiation analysis = structural and molecular analysis but necessity of samples

2009: Project of combination of AGLAE with an ICS in the Louvre for non destructive structural and elemental analysis (XRF, XANES, XRD) as well as for 3D imaging of works of art.

X-ray UV

VIS Louvre Museum

44March 2012

Picosecond Physics at the MIT STC - S. Durbin, Physics Dept.

I. Laser pump deposits energy into the electronic system, and the lattice response can be tracked with an x-ray probe beam.Use high rep rate (>106 Hz), ultrashort pulse length (0.1-5 ps, not available at ANY synchrotron source)) to observe • non-thermal melting, coherent phonons•ferroelectric/complex oxide transitions• porphyrin dynamics

II. X-ray pump, laser probe in semiconductors: Single 1 ps x-ray pulse (1010 x-rays) focused to 10 microns can generate up to 1017 cm-3 instantaneous deep core holes in a semiconductor. Laser monitor of absorption and reflectivity will reveal the quantum kinetic response of plasmons and phonons in this new many-body probe.

Picosecond Physics at the MIT STC - S. Durbin, Physics Dept.

I. Laser pump deposits energy into the electronic system, and the lattice response can be tracked with an x-ray probe beam.Use high rep rate (>106 Hz), ultrashort pulse length (0.1-5 ps, not available at ANY synchrotron source)) to observe • non-thermal melting, coherent phonons•ferroelectric/complex oxide transitions• porphyrin dynamics

II. X-ray pump, laser probe in semiconductors: Single 1 ps x-ray pulse (1010 x-rays) focused to 10 microns can generate up to 1017 cm-3 instantaneous deep core holes in a semiconductor. Laser monitor of absorption and reflectivity will reveal the quantum kinetic response of plasmons and phonons in this new many-body probe.

BacteriophagesFlavivirusesds viruses Alpha viruses

Purdue University

45March 2012

University College London

46March 2012

Robert Feidenhans’l, Niels Bohr Institute, University of Copenhagen

Franz Pfeiffer et al

Lab source setup

Phase shift

CancerousLymph nodeESRF data

Absorption

Aim : Medical Imaging

University of Copenhagen

47March 2012

Conclusions (Predictions)

• Within a decade FEL facilities will achieve single mode laser radiation in the hard x-ray regime with milli-Joule power levels.

• Within two decades superconducting linac-based facilities will have many such beamlines operating across a wide spectral range.

• There is no obvious “next generation” large facility. But….

• Within a decade compact sources less than $10M will offer NSLS I level (2nd generation) x-ray properties.

• Within two decades compact sources will demonstrate coherent emission revolutionizing laboratory-scale capability.

• Large facilities always be the most powerful sources simply due to the physics of electromagnetic radiation from energetic charged particles.

• But the most creative science will most likely come from the laboratory sources, just as with laser sources today, and x-ray sources of the early 20th century.