Cheiron School 2009

X-ray Free Electron Laser

Tsumoru Shintake
XFEL/SPring-8 Accelerator R&D Technical Director
Main Accelerator Construction Leader
SPring-8 Center, RIKENMay 09 2009

SPring-8
Operating ten years

XFEL/SPring-8
Building construction
completed March 2009
SCSS Test Accelerator
Since 2006, EVU user facility

Concept of XFEL/SPring-8
8 GeV
ThermionicElectron Gun C-band accelerator

In-Vacuum Undulators

X-ray Laser

SASE-FELElectron Beam
Beam Dump

1) Electron gun

Low emittance (HN ~ 0.7S mm*mrad)
Higher electron density at the undulator.

2) C-band accelerator

High gradient (Ea ~ 35 MV/m)
Compact accelerator.

3) In-vacuum undulator Short period (Ou ~ 18 mm)
Shorter wavelengthwith lower electron energy.

SCSS to XFEL/SPring-8 Timeline•

2001~2003 SCSS R&D

CeB6 thermionic gun•

2004~2005 SCSS Test Accelerator Construction

0.6 π.mm.mrad @ 1 A DC, 500 kV

X 300 Compression•

2006 June First Lasing 49 nm at test accelerator.

•

2007 Oct. Saturation at 50~ 60 nm•

2006 April XFEL/SPring-8 Construction was funded.
Beam optics design. Technical design.
2007 Technical design, contract.

0.7 π.mm.mrad @ 300 A, 0.7 psec,
250 MeV, 0.3 nC•

2008 Mass-production of hardware components.

•

2009 March. Linac, Undulator hall building completed.
Hardware installation.

X 10 Compression

0.8 π.mm.mrad @ 3k A, 8GeV•

2010 Oct. High power processing 8 GeV accelerator.

•

2011 April~ Beam commissioning. First lasing at 1 A.

Single-crystal CeB6 Cathode for
the SCSS Low-emittance Injector
No HV breakdownfor 4 years daily operation

After 20,000 hours operation
1 crystal changed.
Single-crystal CeB6

500 kV Electron Gun

Diameter : φ3 mm
Temperature : ~1500 deg.C
Beam Voltage : 500 kVPeak Current : 1 A
Pulse Width : ~2 μs

Heating CathodeUse Small Size Cathode…First Strategy for smaller thermal emittance• Thermionic cathode

3mm diameter cathode (CeB6)
is used in a low emittance injector.
(SCSS SPring-8/RIKEN)
Operating Temperature 1450°C

we

3
k BT
2

223 meV

Thermal Emittance

H xN• RF photo-cathode injector.

J rc
2

k BT
m0 c 20.4 ʌ mm-mrad0.28 S mm-mrad/mm

Today’s RF photo injectors use ~ 1 mm spot radius.

H xN

J rc
2

k BTe
m0 c 20.35 ʌ mm-mradSame order!

Te is “measured” effective electron temperature of copper
cathode using 266 nm laser (ref. 2). k Te = 0.27 eV (2360°C).

SCIENCE

Thinking big. Tsumoro
Shintake with a prototype
XFEL at SPring-8.

MATERIALS SCIENCE

Japanese Latecomer Joins Race
To Build a Hard X-ray Laser
X-ray free-electron lasers are the next big thing in high-energy probes of matter.
With U.S. and European machines in the works, Japan wants into the club
SAYO, HYOGO PREFECTURE, JAPAN—It’s thescientific version of keeping up with theJoneses. Once researchers in one region plana big, new experimental device, researchers
everywhere want their own. The latest examp le: x-ray free-electron lasers (XFELs),
which promise beams that are vastly brighter
and with higher energy and shorter pulses
than today’s workhorse synchrotron x-rays.
These “hard” x-ray wavelengths—down tobroad interest for science, it is no surprise that
[researchers] in three regions of the world wantto have a facility of their own,” says Reinhard
Brinkmann, who leads the European effort
based at the German Electron Synchrotron(DESY) research center in Hamburg. “Freeelectron lasers are amazing things which herald a new era in photon science,” says Janos
Hajdu, a synchrotron radiation specialist at
Uppsala University in Sweden.

VOL 314

3 NOVEMBER 2006

or oscillating in lockstep—a quality missing
from synchrotron light.
Although all three planned systems sharethe same basic setup, subtle differences give
each of them strengths and weaknesses. “Thefinal targets of the XFEL projects are the same,but the means are different,” says Tsumoru
Shintake, who heads accelerator development
for Japan’s XFEL.
The first project to come online will be
Stanford’s LCLS. Much of the key researchunderpinning XFELs was done at SLAC
beginning in the early 1990s. And SLAC got ahead start by using a 1-kilometer stretch of its
now-idled linear accelerator, or linac. The
SLAC group estimates that reusing its linac
has saved more than $300 million, giving a
total construction cost of $379 million. LCLS
will have one undulator providing hard and soft
x-rays to up to six experimental stations.
Galayda says the group expects to generate its
first x-rays by July 2008 and to start experiments by March 2009.
Japan’s entry is the SPring-8 Compact
SASE Source (SCSS), just now getting underrconstruction here. Latecomers to the field, theteam is using some homegrown technology to
cut cost and size. “We’re taking the first step
toward making XFELs smaller and cheaper somore [institutions] can consider developing
their own,” boasts SCSS project leader Tetsuya
Ishikawa. Whereas the other two machines will
generate electrons by firing a laser at a metaltarget, the SCSS heats a cathode to produce
electrons. Eliminating the laser simplifies thesystem but requires careful compression of thecloud of electrons before they go into the linac.
The wavelength of the output x-rays is a

T. Shintake@ SCSS & XFEL/SPring-8 2008

SCSS Test Accelerator Performance•••2006 First lasing at 49 nm
2007 Full saturation at 60 nm
2008 User operation statC-bandaccelerator

500 kV Pulse electron gun
CeB6 Thermionic cathodeBeam current 1 Amp.

238 MHzbuncher

476 MHzbooster

In-vacuum
undulator

S-bandbuncherE-beamCharge: 0.3 nC
Emittance: 0.7 S.mm.mrad(measured at undulator)
Four C-band accelerators
1.8 m x 4
Emax = 37 MV/m
Energy = 250 MeV
In-Vacuum Undulators
Period = 15 mm, K=1.3
Two 4.5 m long.

July 䋲䋰䋰䋷, StockholmFirst Lasing at SCSS Prototype Accelerator.
June 15, 2006

T. Shintake, FEL06

CeB6 Thermionic Gun provides stable beam.

Beam Profile
CCD Image
Scale 10 mm

250 MeV Compressor

500 kV Gun

50 MeV Injector Out

Undulator Input

Undulator Output

July 䋲䋰䋰䋷, StockholmFirst Lasing at SCSS Prototype Accelerator.
June 15, 2006

Shintake, Summer 2008

First Lasing at SCSS Prototype Accelerator.

•
•
•
•
•

The first lasing: 49 nm
E-beam energy : 250 MeV
Bunch charge: 0.25 nC
Bunch length: (< 1 pse)Peak Current (> 300 A)•

At moment spectrum
width 0.5 nm is dominatedby e-beam energy
fluctuation ~ 0.2%.

T. Shintake@ SCSS & XFEL/SPring-8 2008

SCSS Test Accelerator User Run Has been Started in 2008••••

50~60 nm, 30 PJ/pulse
Multi-photon absorption
Coherent diffraction imaging
etc.

䌐䌁䌃䋲䋰䋰䋷

Peak Brilliance Evolution• Peak brilliance will be enhanced
by factor of 1010 from 3rdgeneration SR to XFEL.
• 1010 = 101 x 101 x 101 x 107= peak current by factor 10
x lowered emittance by 10
x energy spread lowered by 10
x interference effect 107 by
micro-bunching formation.

Undurator
y
X-ra

on
i
t
a
adi

R

Magnetic
Field

m

r

ct
e
r
E

ea
B
on

Permanent Magnets

Freeware Radiation2D is available at

http://ShintakeLab.com

July 䋲䋰䋰䋷, StockholmInterference EffectShintake, Summer 2008

Physical Origin of Micro-bunching (FEL Action)• Undulator field produces curved trajectory. From this slope, thetangential component of EM wave creates longitudinal field.

Radiation

E

ory
t
c
raje
T
ron
t
c
Ele

D

Radiation Axis

E// = E sin(D) ~ 1/J
E// creates micro-bunching.

FEL Power

Saturation

Exponential
SignalAmplification

SeedingorInfinitely Long
Undulator

Seeding

Shot Noise

Distance Along Undulator

T. Shintake
2007.01

Basic Machine Layout of XFEL/SPring-8

Expected Performance of XFEL/SPring-8

Wavelength< 0.1 nmPeak Power~ 20 GW

X-ray Pulse
Length200 fs ~ 20 fs

X-ray Pulse
EnergyMax 0.4 mJ

Photon Flux

2 x 1011 p/pulse

Peak Brightness

1 x 1033
p/mm2/mrad2/0.1% BW

X-ray Pulse
Repetition

10 ~ 3000 pps(50 bunch x 60 Hz)

Bunch per Pulse

1 ~ 50(4.2 nsec spacing)e Beam8 GeV x 0.3 nC
0.8 πmm.mrad, 3 kA

Expected X-ray pulse of 0.1 nm(SIMPLEX simulation)

XFEL/SPring-8
Building construction
completed March 2009

Experimental Hall
(under construction)
Undulator Hall

400 m Accelerator Tunnel
Klystron Gallery

Machine Assembly Hall

C-band System Configuration
400 V, 3φC-bandKlystron

Klystron Voltage

50 MW RF

Klystron Modulator

150 MW RF

50 MW, 3 usec
RF 5712MHz
RF Compression

25 kV, 5000 A
600V, 80 A

75 MW

150 MWPFN 50 kV
DC 600VÆ DC 50 kV

75 MW

Highly stable
PFN charger< 100 PPMp-p

C-band Accelerator
35 MV/m
50 kV, 1 A

25 kVÆ 350 kVCompact Modulator for 50 MW Klystrons
•
•
•
•
•

Output Power 50 MW RF x 60 pps
50 kV PFN, 1:16 Trans, 350 kV klystron.
Compact 1 m x 1 m x 1.5 m,
Very low noise(<10 Vpp on 200 V heater line)
Water cooled. Max surface temp 45 deg.

Modulators are Arriving to XFEL/SPring-8

Mass Production of Klystrons at TOSHIBA•••

64 C-band klystron
4 S-band klystron1 L-band klystronC-band Klystron5712 MHz, 50 MW
4 μsec, 60 pps
45 % efficiency
Three-cell traveling wave output

how the cloud of electrons whizzing around an atom’s nu
cleus gets arranged by the forces of attraction to the nu
cleus and repulsion from other electrons. These extremely
excited atoms may themselves be harnessed to make aunique laser.

Nanoscale Dynamics
Electronic devices, computer chips, and the liquid crystal
displays on digital watches already use nanoscale materials.
These materials are only billionths of a meter in size andhave specially designed properties.

Plasmas are hot, dense soups of ionized atoms—atoms
missing electrons—and free electrons. Scientists need highdensity plasmas in the attempt to make fusion energy.
LCLS’s x-rays will be able to pass through these plasma“pellets” to scrutinize their nature and behavior.

Building machines and computers from components con
taining only a few thousand atoms has moved from a day
dream to a real endeavor. LCLS will observe these nanoma
chines in action to see how forces like magnetism affecteach part in a material, how large-scale characteristics likeviscosity result from the motion of individual molecules,
and other dynamics that happen on ultra-fast time scales.

A type of plasma called warm dense matter is believed toexist inside proto-stars and giant planets like Jupiter,
accounting for much of the universe’s matter. LCLS will
create and probe this extreme state of matter to further
study the universe.

Protein Molecule
Injection

As engineered materials continue to get smaller and faster,
LCLS will provide the data to build better technology.

With its fast “shutter” speed
and super brightness, LCLS
could take pictures of animportant class of proteinsthat cannot be x-rayed anyother way.

LCLS Beam

Pixel
Detector 1

Pixel
Detector 2

Protein
Molecule
To Mass
Spectrometer

Operating with ultrafast pulses, LCLS will take images ofmolecules dropped into the x-ray beam. Scientists will
merge the series of diffraction patterns of the molecules
in many different positions. The resulting three-dimensional reconstruction will reveal the structures of pro
teins that cannot be crystallized and thus studied anyother way.

X-ray Diffraction Pattern

C-band Accelerator for Multi-bunch Option

13,000 cells are under mass production.

T. Shintake, “Choke Mode Cavity”,
Jpn. J. Appl. Phys. Vol. 31 pp. L1567-L1570, November 1992

Higher Order Mode Damping for Multi-bunch operation.
Maximum 50 bunches x 1 nC, at 4.2 nsec spacing
X-ray 4.2 nsec x 50 bunches will be key forSingle bio-molecule imaging to improve Luminosity.
Sadao Miura, MITSUBISHI Heavy Ind, April 20

HITACHI Cable Co. completed
mass production of C-band cell. June 2009

We made 13,000 piecesof C-band accelerator cell.

Mass Production of C-band Accelerator
at MITSUBISHI Heavy Ind. 2007 ~ 2009
Laser
GuidedPrecision
Machining

MITSUBISHI-Team completed 100 tubes (out of 128)
C-band Accelerator. Photo March 2009

Routinely Operation: C-band High Gradient Test••••

Sample test from mass production.
C-band 1 unit for one month.
35 MV/m is routinely achieved.
(Very low trip rate.)
Processing up to 40 MV/m, 60 pps.

T. Sakurai, PAC2009

Beam Monitor Devices

By Y. Otake team.
Cavity BPMs
0.2 μm resolution was
confirmed with beam

OTR RadiatorSP-8 XFEL Undulator Line
Undulator Lines

Elxperimental Stations

Electron Beam
Bending Magnet

FEL light
5m

UND-ID-1

1.2 m

⏛⍹ขઃ

⏛⍹ขઃ
⏛⍹

⏛⍹ขઃ
ST D
- -V44⏛⍹

ST D- -V44

Q-D-V44

ST D- -V44⏛⍹

ST D- -V44⏛⍹ขઃ

Q-D-V44*%Q T FKGTKVG⏛⍹ Z8

~110 m18 Undulator Segments

Drift Section• GV,PM,CT,BPM• Focusing Q• Phase Shifter• Steering Coils

⏛⍹ขઃ
⏛⍹

Undulator is readyfor mass production.

T. Shintake@ SCSS & XFEL/SPring-8 2009

Undulator is ready for mass production

Undulator Parameter
Undulator Type
Active Length
Undulator Period
Magnetic Circuit
Peak Field Maximum
NominalMaximumK
Gap

NominalMinimum
NominalMaximum Attractive Force

In-Vacuum Planer Undulator
5m
18 mm
Hybrid(NdFeB+Permendur)
1.31 T
1.13 T
2.2
1.9
3.5 mm
4.5 mm~ 6 tonUndulator for XFEL/SPring-8

SciencewithXǦrayFreeElectronLaser
Generation of extreme stateHigh brilliance
x109

Atomically-resolved imaging fornon-crystalline objects

XFEL

Spatialcoherence
100%

Ultrafast pulse< 100 fs

Probing of ultrafast
chemical reaction &phase transition1

Coherentdiffractionimaging
Diffraction image
XFEL

Focusing
deviceReal image (atomic resolution)

SamplePhase retrieval by iterative algorithm
Target: Single molecule2Optical Microscope
Lens
White

Image

ObjectLight
Reflection
Refraction

Lensless Diffraction Microscope
Detector Numerical Process
ObjectIntensity data

Coherent
Phase retrive

X-ray

Wavefront
Diffraction

Image on computer

Iterative Phase Retrieval
Electron density

Amplitude

Phaseforward FFTρ(r)Supportconstraint

ρ(r)’backward FFT

Experimental
Fienup, J.R. 1978. Reconstruction of an object from the modulus of its Fourier transform. Optics Letters, 3: 27-29

Data

Demonstration
Experiments

DESY FLASH VUV FELChapman, H.N., A. Barty and M. Bogan et al. 2006. Femtosecond
diffractive imaging with a soft-X-ray free-electron laser, Nature Physics 2:
839-843

PHYSICAL REVIEW E 78, 041906 共2008兲

Possibility of single biomolecule imaging with coherent amplificationof weak scattering x-ray photons
Tsumoru Shintake
RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
共Received 23 April 2008; revised manuscript received 21 August 2008; published 3 October 2008兲
The number of photons produced by coherent x-ray scattering from a single biomolecule is very small
because of its extremely small elastic-scattering cross section and low damage threshold. Even with a highx-ray flux of 3 ⫻ 1012 photons per 100-nm-diameter spot and an ultrashort pulse of 10 fs driven by a future
x-ray free electron laser 共x-ray FEL兲, it has been predicted that only a few 100 photons will be produced fromthe scattering of a single lysozyme molecule. In observations of scattered x rays on a detector, the transfer ofenergy from wave to matter is accompanied by the quantization of the photon energy. Unfortunately, x rays
have a high photon energy of 12 keV at wavelengths of 1 Å, which is required for atomic resolution imaging.
Therefore, the number of photoionization events is small, which limits the resolution of imaging of a single
biomolecule. In this paper, I propose a method: instead of directly observing the photons scattered from thesample, we amplify the scattered waves by superimposing an intense coherent reference pump wave on it andrecord the resulting interference pattern on a planar x-ray detector. Using a nanosized gold particle as areference pump wave source, we can collect 104 – 105 photons in single shot imaging where the signal from asingle biomolecule is amplified and recorded as two-dimensional diffraction intensity data. An iterative phaseretrieval technique can be used to recover the phase information and reconstruct the image of the single
biomolecule and the gold particle at the same time. In order to precisely reconstruct a faint image of the single
biomolecule in Angstrom resolution, whose intensity is much lower than that of the bright gold particle, I
propose a technique that combines iterative phase retrieval on the reference pump wave and the digital Fouriertransform holography on the sample. By using a large number of holography data, the three-dimensional
electron density map can be assembled.
DOI: 10.1103/PhysRevE.78.041906

PACS number共s兲: 87.85.Ng, 42.30.Rx, 07.85.Tt, 42.40.Ht

I. INTRODUCTION

Protein crystallography has advanced through the use ofhigh-quality x-ray beams generated by synchrotron lightsources 关1兴 and with the development of high-brightness
x-ray beams produced by an undulator device placed in lowemittance electron storage rings 关2兴. The increase in thebrightness of x-ray beams has made it possible to increase
the flux incident on small protein crystals. Currently, crystals
with a diameter of 100 ␮m are routinely analyzed, and the10-␮m-diameter crystals are under investigation. It is comparatively easier to produce high-quality small crystals thanlarger crystals with a lesser number of defects.
However, crystallization of membrane proteins is extremely challenging because they require detergents to maintain them in isolation or solution; unfortunately, such detergents often interfere with the crystallization process.
Membrane proteins form a large component of genomes andinclude several proteins of great physiological importance,such as ion channels and receptors 关3兴.
Recently, the practical applications of single-pass freeelectron lasers 共FELs兲 关4,5兴 at short wavelengths have increased as a result of long-term research and development ofimportant devices and technologies, such as low-emittanceelectron sources, accurate undulator devices, and highprecision electron-beam control techniques. Currently, threelarge x-ray FELs emitting 1 Å x-ray laser beams are underdevelopment and will be available for use in the next few
years 关6–8兴.
Since x-ray FELs produce extremely high peak powerwith a short pulse duration, the potential use of these devices
1539-3755/2008/78共4兲/041906共9兲

to determine the structure of a single biomolecule or individual cells from scattered photons in one shot has been examined 关9兴. Through a computer simulation, which considers
in detail the damage associated with photoabsorption andAuger electron emission and their various effects, it has been
demonstrated that coherently scattered photons from a single
biomolecule can be collected using femtosecond pulses before atoms start drifting due to Coulomb forces. However,the number of available photons is quite limited. A previous
report has predicted that a maximum of 682 photons can be
scattered from a single lysozyme molecule. In the calculation, however, unrealistic parameters have been assumed:
5 ⫻ 1013 photons per pulse in a 100-nm-diameter spot with a
1-fs pulse duration at a wavelength of 1 Å. If we refer to thedesign parameters of the x-ray FELs currently under development, the feasible parameters appear to be 3 ⫻ 1012 photons or less per pulse in a 100-nm-diameter spot with a 10-fs
pulse duration; with these parameters, only 100 photons
would be scattered into scattering angle for 2 – 30 Å resolution. This is an extremely small number, which makes it
impossible to carry out single-shot imaging.
In this paper, initially, I discuss the double slit thought
experiment in order to show signal amplification phenomena
associated with the interference effect. Then, I propose amethod in which the scattered photons are amplified by superimposing a reference pump wave and the resulting interference fringes are recorded on a planar x-ray detector; similar to the technique followed in holography. On the basis of
the four-slit thought experiment, I discuss the signal contents
in the interference fringes. To recover an image, I discuss the041906-1©2008 The American Physical Society

T.Shintake 2009.Feb

Physical Origin of Difficulty• In observations of scattered X-rays on a detector, thetransfer of energy from wave to matter is accompaniedby the quantization of the photon energy. Unfortunately,
X-rays have a considerably high photon energy of 12
keV at wavelengths of 1 Å, which is required for atomic
resolution imaging.
• Therefore, the number of photoionization events is
considerably less, which limits the resolution of theimaging of a single biomolecule.

letters to natureaEnergyTotal
Kinetic
Potential

Primary
Auger
I(t)

–2

0

2

0

–2

1×108

2

0

b
2×108

2,500
2,000
1,500
1,000
500
0

1×108

–10

0

10

–10

0

10

kJ mol–1

Number of events

Ionization events

2×108

2,500
2,000
1,500
1,000
500
0

0

c
2,500
2,000
1,500
1,000
500
0

2×108
1×108

–50

0

50

Time (fs)

–50

0

50

0

Time (fs)Figure 1 Ionization of a lysozyme molecule in intense X-ray pulses. The full width at half
maximum (FWHM) of the pulse was 2 fs (a), 10 fs (b) or 50 fs (c). The integrated X-ray
intensity was 3 ´ 1012 (12 keV) photons per 100-nm diameter spot (3.8 ´ 106 photons perAÊ2) in all cases. The creation of a large number of positive charges owing to primary
ionization by X-rays (photoelectric effect and Compton scattering), and the subsequentAuger emissions (left) result in a rise in the potential (mainly electrostatic) energy of thesample (right). The degree of conversion of potential energy into kinetic energy during the
X-ray exposure is inertia limited, and so depends strongly on the duration of the pulse. The
gaussian shape of the X-ray pulse is indicated.

Figure 2 Explosion of T4 lysozyme (white, H; grey, C; blue, N; red, O; yellow, S) induced byradiation damage. The integrated X-ray intensity was 3 ´ 1012 (12 keV) photons per 100nm diameter spot (3.8 ´ 106 photons per AÊ2) in all cases. a, A protein exposed to an X-ray
pulse with an FWHM of 2 fs, and disintegration followed in time. Atomic positions in the®rst two structures (before and after the pulse) are practically identical at this pulse length

because of an inertial delay in the explosion. Rnucl = 3%, Relec = 11% b, Lysozyme exposedto the same number of photons as in a, but the FWHM of the pulse was 10 fs. Images show
the structure at the beginning, in the middle and near the end of the X-ray pulse. Rnucl =7%, Relec = 12% c, Behaviour of the protein during an X-ray pulse with an FWHM of 50 fs.
Rnucl = 26%, Relec = 30%.

NATURE | VOL 406 | 17 AUGUST 2000 | www.nature.com© 2000 Macmillan Magazines Ltd

753

letters to nature
and are released at different times. Relevant K-hole lifetimes
determined from Auger line-widths9 are 11.1 fs (C), 9.3 fs (N),
6.6 fs (O) and 1.3 fs (S). Shake-up excitations and interference
between decay channels will modulate this picture.
Another effect is Compton (or inelastic) scattering, which represents a direct momentum transfer from an X-ray photon to a boundelectron, so that the X-ray photon is scattered with a reduced energy.
If the recoil energy taken up by the electron is greater than its shellbinding energy, the atom will be ionized. The inelastic cross-sectionof carbon, nitrogen and oxygen is about 3% of the corresponding

photoelectric cross-sections10,11, whereas the inelastic cross-sectionof hydrogen is much higher than its photoelectric cross-section.
The average velocities of photoelectrons (43 nm fs-1) and Auger
electrons (7 nm fs-1) enable these electrons to escape the protein
environment in less than a femtosecond during early phases of an
exposure. At these velocities the inelastic electron scattering crosssections for carbon1 lie between 0.1 and 2.0 AÊ2, such that roughly
one electron in ®ve will deposit additional energy into the moleculefrom which it escapes, and may also remove outer-shell electrons12.
In late phases of an exposure, a signi®cant fraction of the emitted

Figure 3 Elastic scattering from a variety of samples. a±c, Simulated diffraction images
on a 128 ´ 128 pixel planar detector (100 mm ´ 100 mm) normal to and centred at thebeam, and placed 100 mm from the sample. The background was not modelled, and100% detective quantum ef®ciency was assumed. The integrated X-ray intensity was
3 ´ 1012 (12 keV) photons per 100-nm diameter spot (3.8 ´ 106 photons per AÊ2); thepulse length was 10 fs. The resolution is 2.2 AÊ at the rim in a±c. cpp, counts per pixel.
a, Scattering from a single tomato bushy stunt virus capsid. b, Scattering from a5 ´ 5 ´ 5 cluster of lysozyme molecules with an average r.m.s. conformational deviationof 0.2 AÊ to model an imperfect lattice. c, Scattering from a single molecule of lysozyme. d,A planar section through the molecular transform (that is, a simulated continuous
scattering image) of a single T4 lysozyme molecule under ideal conditions without sample
movement or damage. Resolution at the rim of d corresponds to 2.0 AÊ. Structure factor
amplitudes are coloured logarithmically (magenta, high; green, low). The section isperpendicular to the z axis, and crosses through the origin at the centre of the image,revealing centric symmetry.

754© 2000 Macmillan Magazines Ltd

NATURE | VOL 406 | 17 AUGUST 2000 | www.nature.com

Single Biomolecule Imaging with XFEL(Heterodyne Detection + Holographic Recording)“Weak diffraction from biomolcule is amplified by 10 ~ 50 times (Heterodyne)on the coherent reference wave from nano-particle, providing
100~1000 times more photons”
T. Shintake, PR-E 78, 041906 (2008)

X-ray FEL Beam

Single Biomolecule
Nano Particle of Heavy Atoms
as Coherent Reference Wave Source

Heterodyne
Amplification
Holographic
RecordingX-ray Heterodyne Detection

T. Shintake 2003

• X-ray heterodyne detection
using reference X-ray P1 on the small signal P2( P ± P ) = P ± 2 PP + P= P (1 ± 2 P / P + P / P ) P (1 ± 2 P / P )
P± =

2

1

2

1

1

1

2

1

1

2

1

1 2

2

2

• Even if P2 is 10-6 times smaller, the signal isamplified to 10-3 level. This is +30 dB amplification.
T. Shintake CAS School Brunnen 2-9 July 2003

T.Shintake 2009.Feb

Does noise increase or decrease?
• S/N due to the electrical noise in detector
instrument can be easily improved as the signal
growing.
• Question is the statistical noise associated withquantization of energy in photo-ionization
process in CCD or film detector.
• Since amplitude of the interference patternincrease as ∝ I , and statistical noise also
increases as ∝ I , thus S/N becomes constant,and looks like not been improved.

S / N |holography = S / N |direct

ND Filter X1/200PHYSICAL REVIEW E 78, 041906 共2008兲

TSUMORU SHINTAKEGold Particle

X-ray

where ⌬␾ij = ␾ j − ␾i is the phase difference given by

Lysozyme, 14.4 kD1000 C, N, O atoms

1000 atoms⌬␾ij = ␾ j − ␾i =

Link

5

0
Four-Slit Thought Experiment(1) (2)
I = 200

10

(nm)

10

(3)

(4)

1

0.1

15

FIG. 4. 共Color online兲 Conceptual diagram of a single lysozyme
molecule linked to a gold particle 共diameter of atoms is not drawn
to scale兲. The gold particle produces 200 times more coherent x-ray
scattering than the single lysozyme molecule. The bar at the bottomof the figure represents a four-slit thought experiment.

Fourier transform holography uses spherical waves as reference waves to record the phase of an object wave. The
intensity of the reference wave is chosen such that it is comparable to that of the object wave to obtain the best contrast.
To obtain better image quality, the size of the reference wave
source should be considerably smaller than the object. The
image-recovery process in Fourier transform holography issimple; basically, an inverse Fourier transform performed on
the obtained intensity data provides the real image. This
technique is well established, and Fourier transform holography has been successfully applied to the observation of magnetic nanostructures in thin films using soft x rays 关18兴.
In the method, the intensity of the reference wave is considerably higher; as a result, the reference wave amplifies the
weak signal and also provides a phase reference. However,the diameter of the gold particle is comparable to that of thesingle biomolecule and it is not a point source. Hence, thescattered x rays cannot be simple spherical waves. In fact,
they form a speckle pattern, whose phase and amplitude are
not known. Therefore, simple holographic image processing
cannot be applied in this case.
To solve this problem, I have devised a thought experiment with each slit, in the double-slit experiment, being subdivided into two slits, i.e., there are four slits in total as
shown at the bottom of Fig. 4. The gold particle, the internal
structure or an imperfection of the gold particle, the sample,
and the internal structure of the sample function as the first,
second, third, and fourth slits, respectively. This is the simplified model of a gold-labeled molecule. When coherent
light is incident, the probability of finding a photon on thescreen is given by
4

4

i=1

j=1

I = 兩␺兩2 = ␺*␺ = 兺 ␺i* 兺 ␺ j = I1 + 2冑I1I2 cos ⌬␾12
+ 2冑I1I3 cos ⌬␾13 + 2冑I1I4 cos ⌬␾14 + I2
+ 2冑I2I3 cos ⌬␾23 + 2冑I2I4 cos ⌬␾24 + I3
+ 2冑I3I4 cos ⌬␾34 + I4 ,

共7兲

2␲dij
sin共2␪兲.
␭共8兲

Here, Ii represents the flux from the ith slit, 2␪ is the scattering angle 共as defined in crystallography兲, and dij is the
distance between the i and jth slits. The slit locations andflux ratio suitable for our example case shown in Fig. 4 are
as follows: d12 = 1.5 nm, d23 = 8.5 nm, d34 = 2 nm, I1 = 200,
I2 = 10, I3 = 1, I4 = 0.1, and ␭ = 1 Å. Figure 5共a兲 shows the flux
density distribution estimated using Eq. 共7兲. The distribution
is considerably complicated because the fringes are formedby the interference of four waves.
In Fig. 5共c兲, the curve at the bottom indicates the scatteredwave from the biomolecule when it is directly observed
without using the reference pump wave. It is a very weaksignal with a relative intensity of approximately 1. In practice, the signal is quantized by the photon energy, leading toa loss of detailed information. The dashed curve 共magnified
10 times兲 also shows an interference pattern, which represents the internal structure of the biomolecule; our aim is to
study this pattern. By superposition of the reference pumpwave, the signal wave is amplified, and the resulting interference pattern is recorded. In order to demonstrate the amplification effect clearly, the reference pump wave is assumed to be perfect with ␺2 = 0. In Fig. 5共c兲, the curve at the
top shows the amplified signal, which is recorded by the
amplitude modulation of the interference pattern. From Eq.
共7兲, we find thatI = I1 + 2冑I1I3 cos ⌬␾13 + 2冑I1I4 cos ⌬␾14 + I3
+ 2冑I3I4 cos ⌬␾34 + I4 .

共9兲In our experiment, the reference wave has a considerably
higher intensity than that from the sample; I1 Ⰷ I3 ⬎ I4.
Hence, we can eliminate the last three terms 共direct wave兲
and Eq. 共9兲 becomesI ⬇ I1 + 2冑I1I3 cos ⌬␾13 + 2冑I1I4 cos ⌬␾14 .

共10兲These two amplified signals have different frequencies,
which results in the formation of a beat wave at ⌬␾14
− ⌬␾13 = ⌬␾34, whose frequency is equal to that of the interference signal of the direct sample signal. As discussed later,
the sample signal is amplified and recorded as a beat wave.
The signal gain is given byG==

modulation in amplified signal
modulation in direct signal
2共冑I1I3 + 冑I1I4兲 − 2共冑I1I3 − 冑I1I4兲4 冑I 3 I 4

=

冑I1I4
冑
冑I3I4 = I1/I3 .

共11兲
In this example, G = 冑200= 14.1.
The signal to noise ratio S / N is significantly improved asfollows. We assume that noise is caused by statistical fluctuations associated with the quantization process at photoionization. The improvement in S / N can be estimated as041906-4

Shintake, Summer 2008

Who is Shintake?

@ SCSS tunnel
Test Accelerator for XFEL•

Date of Birth 1955, Miyazaki, Kyushu Japan•

1992~1996 FFTB – SLAC “Spot Size Monitor”(Shintake Monitor) 60 nm e with 1 Pm wave•

1996~2000 “C-band R&D” for LC at KEK 5 cm
wave.

•

2000~2006 SCSS R&D Leader e- beam•

2006 First Lasing at SCSS Prototype
Accelerator 49 nm wave•

2006~ Now constructing 8 GeV XFEL/SPring-8
for 0..1 nmm wave

Shintake, Summer 2008

KYUSHUShintake, Summer 2008

MIYAZAKIShintake, Summer 2008

Shintake, Summer 2008

Shintake, Summer 2008

Shintake, Summer 2008

Shintake, Summer 2008

Design accelerator as creating images like art

Shintake, Summer 2008

Klystron Modulator for
C-band, S-band 50 MW KlystronsSummary•

So many different efforts are coherently contributing to theproject. They are almost on the time schedule.

••

Building construction has been completed.
Accelerator component installation has been started.
~ 1 year installation.

••

October 2010, We start high power operation of accelerator.
Spring 2011, we start beam commissioning.