XFEL
X-ray Free Electron Laser

Three XFEL Projects in the World
XFEL/SPring-8 in Hyogo, Japan
E-XFEL, DESY in Hamburg, Germany
LCLS, SLAC in California, USA

A New Light Source for Tomorrow

E-XFELLCLS

XFEL/SPring-8
Himeji
Kobe

Kyoto

Osaka
Tokyo

XFEL/SPring-8

Success of First Lasing at the Test Accelerator
A light source for tomorrow is closer than ever to becoming a reality(MW)

Peak PowerFree ElectronLaser

Interference patternby coherent light

NormalUndulator Radiation(Magnified 10 times)
Charge (nC)

The peak power increases
exponentially with the electroncharge.

The SPring-8 Compact SASE
Source (SCSS) test accelerator wasconstructed to facilitate the experimental study of XFEL technology.
The accelerating energy is 250 MeV(only 1/32 of the 8 GeV capacity ofthe XFEL machine), but all basic
components are included in its
design. On June 20 2006, lasing
at a wavelength of 49 nm wasobserved. This is a remarkable milestone for the Japan's XFEL project.

SPring-8 Joint Project for XFELRIKEN (The Institute of Physical and Chemical Research)
JASRI (Japan Synchrotron Radiation Research Institute)
1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
Tel: +81-791-58-2849, Fax: +81-791-58-2862
URL: http://www.riken.jp/XFEL/ E-mail: project-xfel@riken.jp

SPring-8 Joint Project for XFEL

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

XFEL : A New Light Source for Tomorrow

XFEL Project : A Key Technology for Japan

X-ray Free Electron Laser (XFEL) heralds the dawn of a new era in Science

The XFEL adjacent to SPring-8 will provide great benefit to users

Throughout history, the development of new optical instruments and the discovery of new lightsources have given rise to great leaps forward in science. Early use of the telescope provided indisputable proof of the Copernican system; the motion picture enabled mankind to observe an instantof movement; and the microscope made it possible to see individual cells in living organisms.

The X-ray Free Electron Laser Project was selected by the Japanese government as one of theKey Technologies of National Importance in 2006, and launched by RIKEN the same year. The 700
m-long 8 GeV XFEL is now under construction and will be operational in FY 2010.

In the late 19th century, scientific experiments exploited the high transmission capability of X-rays,leading to the development of diagnostic probes that contributed greatly to advances in medicine.
Further applications using X-rays as diffraction probes enabled scientists to observe the nano-world
for the first time and even to analyze DNA structures at the atomic level. More complex protein
structures are currently analyzed by much stronger X-rays generated from synchrotrons such as
SPring-8 (Super Photon ring-8GeV) in Japan.
The development of the lasers in the 20th century inspired the scientific world as it served as acompletely new light source to conduct experiments. Laser disk technology eventually enabled themass production of DVDs and CDs. Additional uses of lasers in high-speed optical communications
expedited the development of the internet backbone.
After substantial advances in X-ray and laser technology, scientists began to ask for an evenstronger light source to examine real images of atoms in 3 dimensions. X-rays combining the features of Lasers at the Free Electron state (XFEL) may be the most promising light source for the
next generation of scientific exploration and discovery. XFEL radiation will deliver one billion times
brighter and 1000 times shorter pulses than existing X-ray sources. Scientists today are only beginning to imagine the plethora of applications that will result from advancement of XFEL technology.

n Laser
X-ray Free ElectroThe XFEL facility is built next to the SPring-8 storage ring for two fundamental reasons: First tobenefit from SPring-8 numerous breakthroughs in accelerator-driven light sources technology inorder to build a compact facility; Secondly for the great synergetic effect of the XFEL and SPring-8
facilities on the progress of Photon Science. For instance, laser-pumping and SR-probing
techniques offer a powerful mean of investigating the atomic and chemical changes of materials,
going beyond conventional atomic/molecular imaging: the intense radiation of the XFEL can excite
atoms or molecules to extremely exotic states, and the whole processes of transitions can beprobed afterwards by SPring-8 X-rays.
Japan s XFEL Project is led by the RIKEN-JASRI Joint Team. A 250-MeV Test Accelerator wasbuilt in 2005, and on June 20 2006, the team successfully generated VUV-laser pulses at 49 nm.
This achievement marked a significant step toward the completion of Japan s X-ray FEL.
The XFEL has drawn great interest throughout the world: DESY (Deutsches ElektronenSynchrotron, Germany) has launched the European XFEL Project in 2007 (completion expectedin 2013), while SLAC (the Stanford Linear Accelerator Center, USA) is developing its XFELmachine, the Linac Coherent Light Source (LCLS), with operation planned for 2009.

(XFEL)

SPring-8

1

XFEL X-ray Free Electron Laser

XFEL X-ray Free Electron Laser

2

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

XFEL : A New Light Source for Tomorrow

XFEL Project : A Key Technology for Japan

X-ray Free Electron Laser (XFEL) heralds the dawn of a new era in Science

The XFEL adjacent to SPring-8 will provide great benefit to users

Throughout history, the development of new optical instruments and the discovery of new lightsources have given rise to great leaps forward in science. Early use of the telescope provided indisputable proof of the Copernican system; the motion picture enabled mankind to observe an instantof movement; and the microscope made it possible to see individual cells in living organisms.

The X-ray Free Electron Laser Project was selected by the Japanese government as one of theKey Technologies of National Importance in 2006, and launched by RIKEN the same year. The 700
m-long 8 GeV XFEL is now under construction and will be operational in FY 2010.

In the late 19th century, scientific experiments exploited the high transmission capability of X-rays,leading to the development of diagnostic probes that contributed greatly to advances in medicine.
Further applications using X-rays as diffraction probes enabled scientists to observe the nano-world
for the first time and even to analyze DNA structures at the atomic level. More complex protein
structures are currently analyzed by much stronger X-rays generated from synchrotrons such as
SPring-8 (Super Photon ring-8GeV) in Japan.
The development of the lasers in the 20th century inspired the scientific world as it served as acompletely new light source to conduct experiments. Laser disk technology eventually enabled themass production of DVDs and CDs. Additional uses of lasers in high-speed optical communications
expedited the development of the internet backbone.
After substantial advances in X-ray and laser technology, scientists began to ask for an evenstronger light source to examine real images of atoms in 3 dimensions. X-rays combining the features of Lasers at the Free Electron state (XFEL) may be the most promising light source for thenext generation of scientific exploration and discovery. XFEL radiation will deliver one billion times
brighter and 1000 times shorter pulses than existing X-ray sources. Scientists today are only beginning to imagine the plethora of applications that will result from advancement of XFEL technology.

n Laser
X-ray Free ElectroThe XFEL facility is built next to the SPring-8 storage ring for two fundamental reasons: First tobenefit from SPring-8 numerous breakthroughs in accelerator-driven light sources technology inorder to build a compact facility; Secondly for the great synergetic effect of the XFEL and SPring-8
facilities on the progress of Photon Science. For instance, laser-pumping and SR-probing
techniques offer a powerful mean of investigating the atomic and chemical changes of materials,
going beyond conventional atomic/molecular imaging: the intense radiation of the XFEL can excite
atoms or molecules to extremely exotic states, and the whole processes of transitions can beprobed afterwards by SPring-8 X-rays.
Japan s XFEL Project is led by the RIKEN-JASRI Joint Team. A 250-MeV Test Accelerator wasbuilt in 2005, and on June 20 2006, the team successfully generated VUV-laser pulses at 49 nm.
This achievement marked a significant step toward the completion of Japan s X-ray FEL.
The XFEL has drawn great interest throughout the world: DESY (Deutsches ElektronenSynchrotron, Germany) has launched the European XFEL Project in 2007 (completion expectedin 2013), while SLAC (the Stanford Linear Accelerator Center, USA) is developing its XFELmachine, the Linac Coherent Light Source (LCLS), with operation planned for 2009.

(XFEL)

SPring-8

1

XFEL X-ray Free Electron Laser

XFEL X-ray Free Electron Laser

2

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

What is XFEL ?

How to Generate XFEL Radiation

The resolution of optical microscopes
is limited by the wavelength of light.
With X-rays, which have a wavelength
10,000 times shorter than that of visible
light, atomic resolution can be achieved. Conventional X-ray sources(including synchrotron radiation sources) are not coherent (the wave field isnot perfectly aligned). Laser canproduce coherent light with a pair ofmirrors. For X-rays, unfortunately, suchmirrors cannot be used due to the low
reflectivity. This limitation has motivatedscientists to explore a new laser technology called X-ray Free-Electron
Laser (XFEL), which can work without
mirrors.

The source of XFEL radiation is a bunch of electrons emitted from a linear accelerator at a velocity close to the speed of light. This electron beam is wiggled in an array of magnets (called anundulator). The weak radiation initially emitted from the electron beam imprints a small density
modulation on the beam itself. The modulation and the radiation grow in synergy in the undulator
field. Finally the radiation energy is dramatically amplified. This process, called Self-Amplified Spontaneous Emission (SASE), is the basis for the generation of XFEL radiation. To generate SASE efficiently requires a small, collimated electron beam, which in turn requires a high-quality electron
gun and a bunch compression system.

Design Parameters

Japan’s Newest Technologies for Compact XFELThe XFEL machine is designed to be compact in order to contain the construction cost and toimprove the operational stability. The compact XFEL is supported by Japan’s original technologies.

Electron gun

8 GeV

Electron Beam Size

40 μm

X-ray Wavelength>0.06 nm

X-ray Peak Power

5 GW

X-ray Pulse Length<100 fsec

X-ray Peak Brilliance1033 photons/s/mm2/mrad2/0.1% b.w.

Accelerator

Free electrons

Undulator

Synchrotron radiation

CeB6 Cathode EmitterC-bandAccelerating
Structure

A high-quality electron beam islaunched from a CeB6 electron gun.

The C-band accelerator swiftly
increases the electron energy.

The initial conditions of the electron beam determine the final performance of XFEL radiation. SPring-8 developed a special thermionicelectron gun that uses a single-crystal cerium-hexaboride (CeB6)
cathode to emit a small, collimated and stable electron beam. Thebeam is transported to the bunch compression system where thepeak current increases up to several kilo-amperes for the XFEL
generation.
3Electron Energy

XFEL X-ray Free Electron Laser

The energy of the electron beam is boosted to 8 GeV by the C-band
linear accelerator : this accelerating structure was developed bySPring-8 in collaboration with KEK. Thanks to the C-band increased
acceleration gradient (35 MeV/m) it is possible to reduce the total
length of the accelerator. A total of 128 2 m accelerating structures,
machined with sub-micron accuracy, will be aligned in the 400 m tunnel.

X-ray laser

In-vacuum
Undulator

The in-vacuum undulator generates
strong XFEL radiation.
The electron beam is injected into the undulator to generate XFEL
radiation. The in-vacuum undulator technology, developed in SPring-8,
was adopted to reach shorter wavelength radiation with a shorter
magnetic period. This technology enables us to reduce the electronenergy and leads to contain the total cost of construction.

XFEL X-ray Free Electron Laser

4

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

What is XFEL ?

How to Generate XFEL Radiation

The resolution of optical microscopes
is limited by the wavelength of light.
With X-rays, which have a wavelength
10,000 times shorter than that of visible
light, atomic resolution can be achieved. Conventional X-ray sources(including synchrotron radiation sources) are not coherent (the wave field isnot perfectly aligned). Laser canproduce coherent light with a pair ofmirrors. For X-rays, unfortunately, suchmirrors cannot be used due to the low
reflectivity. This limitation has motivatedscientists to explore a new laser technology called X-ray Free-Electron
Laser (XFEL), which can work without
mirrors.

The source of XFEL radiation is a bunch of electrons emitted from a linear accelerator at a velocity close to the speed of light. This electron beam is wiggled in an array of magnets (called anundulator). The weak radiation initially emitted from the electron beam imprints a small density
modulation on the beam itself. The modulation and the radiation grow in synergy in the undulator
field. Finally the radiation energy is dramatically amplified. This process, called Self-Amplified Spontaneous Emission (SASE), is the basis for the generation of XFEL radiation. To generate SASE efficiently requires a small, collimated electron beam, which in turn requires a high-quality electron
gun and a bunch compression system.

Design Parameters

Japan’s Newest Technologies for Compact XFELThe XFEL machine is designed to be compact in order to contain the construction cost and toimprove the operational stability. The compact XFEL is supported by Japan’s original technologies.

Electron gun

8 GeV

Electron Beam Size

40 μm

X-ray Wavelength>0.06 nm

X-ray Peak Power

5 GW

X-ray Pulse Length<100 fsec

X-ray Peak Brilliance1033 photons/s/mm2/mrad2/0.1% b.w.

Accelerator

Free electrons

Undulator

Synchrotron radiation

CeB6 Cathode EmitterC-bandAccelerating
Structure

A high-quality electron beam islaunched from a CeB6 electron gun.

The C-band accelerator swiftly
increases the electron energy.

The initial conditions of the electron beam determine the final performance of XFEL radiation. SPring-8 developed a special thermionicelectron gun that uses a single-crystal cerium-hexaboride (CeB6)
cathode to emit a small, collimated and stable electron beam. The
beam is transported to the bunch compression system where thepeak current increases up to several kilo-amperes for the XFELgeneration.
3

Electron Energy

XFEL X-ray Free Electron Laser

The energy of the electron beam is boosted to 8 GeV by the C-band
linear accelerator : this accelerating structure was developed bySPring-8 in collaboration with KEK. Thanks to the C-band increased
acceleration gradient (35 MeV/m) it is possible to reduce the total
length of the accelerator. A total of 128 2 m accelerating structures,
machined with sub-micron accuracy, will be aligned in the 400 m tunnel.

X-ray laser

In-vacuum
Undulator

The in-vacuum undulator generates
strong XFEL radiation.
The electron beam is injected into the undulator to generate XFEL
radiation. The in-vacuum undulator technology, developed in SPring-8,
was adopted to reach shorter wavelength radiation with a shorter
magnetic period. This technology enables us to reduce the electronenergy and leads to contain the total cost of construction.

XFEL X-ray Free Electron Laser

4

Met hods Tar gets

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

XFEL New Science and Technologies to Create ①Pump

Coherent X-ray imaging using XFEL is apromising technology to obtain theatomic-level resolution microscopy forvarious materials.

light② Probe lightsampledetector

Coherent scattering pattern   
SampleFourier transformation

Phase retrieval

Femto-second XFEL pulses canprobe the ultra-fast movement ofmaterials.

Clear image of organism    

Analysis of new materials leads to the generation of new functional products in biology, andpharmacy.
membrane protein

cell membrane 





The ultra-short wavelength of theXFEL will be helpful to create newfunctional materials.

The XFEL will enable the observation of live cells: real time dataacquisition will open a new way forthe study of cell biology.

  
The ultra-high power of theXFEL enables us to investigate extreme conditions for
astronomy, plasma science,and fundamental physics.

5XFEL X-ray Free Electron LaserXFEL X-ray Free Electron Laser

6Met hods Tar gets

XFEL

X-ray Free Electron Laser

XFEL
X-ray Free Electron Laser

XFEL New Science and Technologies to Create ①Pump

Coherent X-ray imaging using XFEL is apromising technology to obtain theatomic-level resolution microscopy forvarious materials.

light② Probe lightsampledetector

Coherent scattering pattern   Sample

Fourier transformation

Phase retrieval

Femto-second XFEL pulses canprobe the ultra-fast movement ofmaterials.

Clear image of organism    Analysis of new materials leads to the generation of new functional products in biology, andpharmacy.
membrane protein

cell membrane 

The ultra-short wavelength of theXFEL will be helpful to create newfunctional materials.

The XFEL will enable the observation of live cells: real time dataacquisition will open a new way forthe study of cell biology.

  The ultra-high power of theXFEL enables us to investigate extreme conditions forastronomy, plasma science,and fundamental physics.

5XFEL X-ray Free Electron Laser

XFEL X-ray Free Electron Laser

6XFEL
X-ray Free Electron Laser

Three XFEL Projects in the World
XFEL/SPring-8 in Hyogo, Japan
E-XFEL, DESY in Hamburg, Germany
LCLS, SLAC in California, USA

A New Light Source for Tomorrow

E-XFELLCLS

XFEL/SPring-8
Himeji
Kobe

Kyoto

Osaka
Tokyo

XFEL/SPring-8

Success of First Lasing at the Test Accelerator
A light source for tomorrow is closer than ever to becoming a reality(MW)

Peak PowerFree ElectronLaser

Interference patternby coherent light

NormalUndulator Radiation(Magnified 10 times)
Charge (nC)

The peak power increases
exponentially with the electroncharge.

The SPring-8 Compact SASE
Source (SCSS) test accelerator wasconstructed to facilitate the experimental study of XFEL technology.
The accelerating energy is 250 MeV(only 1/32 of the 8 GeV capacity ofthe XFEL machine), but all basic
components are included in its
design. On June 20 2006, lasing
at a wavelength of 49 nm wasobserved. This is a remarkable milestone for the Japan's XFEL project.

SPring-8 Joint Project for XFELRIKEN (The Institute of Physical and Chemical Research)
JASRI (Japan Synchrotron Radiation Research Institute)
1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
Tel: +81-791-58-2849, Fax: +81-791-58-2862
URL: http://www.riken.jp/XFEL/ E-mail: project-xfel@riken.jp

SPring-8 Joint Project for XFEL