Proceedings of IBIC2012, Tsukuba, JapanTUPB57EXTREME LIGHT INFRASTRUCTURE (ELI BEAMLINES) –RESEARCH AND TECHNOLOGYWITH NEW ULTRA-SHORT PULSE INTENSE LASER DRIVEN SOURCES
OF ENERGETIC PHOTONS AND CHARGED PARTICLES

Abstract
We are giving an overview on the development of the“Extreme Light Infrastructure (ELI) Beamlines facility”,
which will be a high-energy, repetition-rate laser pillar of
the ELI project, [1]. It will be an international facility forboth academic and applied research, slated to provide user
capability from the beginning of 2016. The main purposeof the facility is the generation and applications of laser
driven high-brightness X-ray sources and accelerated
particles (electrons, protons and ions).
The laser system will be delivering pulses with length
ranging between 10 and 150 fs and will provide highenergy Petawatt and 10-PW peak powers.
The short photon wavelength (20 eV-1 MeV) laser
driven sources are either based on direct interaction of thelaser beam with a gaseous or solid target or will firstaccelerate electrons which then will interact with laser
produced wigglers or directly injected into undulators.
The main planned short pulse laser driven x-ray andcharged particles sources and their parameters arepresented together with basic requirements on the relevantbeam detectors.

LASER SOURCESELI experimental area is divided into six experimental
halls E1 to E6 (see Fig. 1), where a wide range of

secondary x-ray or charged particle sources driven by aset of laser sources is located. The developed state-of-theart laser sources are divided into four systems L1 to L4,each providing a specific range of pulse energies, lengths
and repetition rates.
The laser system L1 involves two high-repetition-rate
kHz beamlines employing the technique of Petawatt Field
Synthesizer (PFS). Upon compression using chirped
mirrors, each of the kHz beamlines will provide about
200 mJ, 20 fs pulses.
The 10-Hz repetition rate L2 system providing PWclass pulses (10 and 20 J) will consist of diode-pumped
multislab lasers pumping a large Ti:sapphire broadband
amplifier and also an OPCPA chain.
The L3 system exploits the technology of multislab
Nd:glass operating at near room temperature and running
at10 Hz repetition rate. The system will provide about
30 J in ~20 fs pulses at 10 Hz, corresponding toapproximately 1.5 PW peak power. Additionally to themain 1.5 PW pulses the system will provide inherently
jitter-free synchronized auxiliary pulses with peak powerof ~50 TW.
The designed laser system finally involves a 10-PW
beamline in the L4 section. The system is designed to
exploit the technology of mixed Nd:glass capable todeliver CPA pulses with bandwidth >13 nm, which are

Figure 1: Overview axonometric layout of the basement floor of the ELI-Beamlines laser building showing theexperimental halls E1 to E6. The halls will be equipped progressively with vacuum chambers, experimental
instrumentation and beam delivery units, according to the project implementation plan. The overall footprint
dimensions of the basement floor are about 110 x 65 m2.
ISBN 978-3-95450-119-9

Overview and Commissioning of Facilities1c 2012 by the respective authors — cc Creative Commons Attribution 3.0 (CC BY 3.0)
Copyright ○L. Pribyl, L. Juha, G. Korn, T. Levato, D. Margarone, B. Rus, S. Sebban, S. Ter-Avetisyan,
ELI-Beamlines, Institute of Physics, Prague, Academy of Sciences Czech Republic.

TUPB57

Proceedings of IBIC2012, Tsukuba, Japan

compressible to 130 fs. The laser chain will consist of
OPCPA pre-amplifiers in the front end and of final
Nd:glass slab amplifiers. This solution, designed toprovide >1.5 kJ pulses, is well suitable for the ELIBeamlines mission in generation of accelerated electrons
where pulses >100 fs are required for acceleration toenergies >10 GeV. The kJ energy available is also ideal
for generation of plasmas for laboratory astrophysics,
another mission of the ELI-Beamlines facility.

SECONDARY SOURCES
The secondary sources driven by the laser systems andhoused in the experimental halls will generate shortintense pulses of X-ray and charged particles. Thesesources will be developed in parallel with the laser
systems and their parameters in various phases of the ELI
project are summarized in Table 1. The detailed overview
of the experimental capabilities of the secondary sources
will be soon available in [2].

c 2012 by the respective authors — cc Creative Commons Attribution 3.0 (CC BY 3.0)
Copyright ○X-ray Sources
The short wavelength (20 eV-1 MeV) short pulse highintensity laser driven sources are either based on directinteraction of the laser beam with a gaseous target, liquid
metal or solid target (High order harmonics generation(HHG), K-alpha and related laser-produced plasma
sources, x-ray lasers and γ-ray flashes) or will firstaccelerate electrons which then will interact with laser
produced wigglers (Betatron radiation) or permanent
magnet undulators. In the latter case two beamlines areforeseen, the Laser Undulator X-ray source, LUX, which
will be commissioned in 2016; and the X-ray Free
Electron Laser Demonstrator, XFELdem, see Fig. 3,
which is planned for the Phase 3. The direct interaction(collision) of laser accelerated electrons with the laser
again will lead to short pulse gamma-ray beams via
Compton or Thomson scattering.
Some of these sources will provide coherent radiation(High order harmonics, x-ray lasers, LUX and
XFELdem).
In HHG, a focused femtosecond pulse laser beam withan intensity in the order of 1014 W/cm2-1015 W/cm2 entersa gas jet, and drives the electrons of a gas. The periodic
recollision of the oscillating E-field driven electrons withthe atomic core leads to an extremely short burst of shortwavelength harmonics.
The K-alpha source employs interaction of a focused
kHz short pulse laser with a metal (or cluster) target. The
target should replenish (liquid metal beam system
considered as nominal solution). The incident laser pulse
generates fast electrons which induce K-shell vacancies,
and incoherent plasma radiation is produced in theprocess of filling of the vacancies. Additionally,
continuum radiation is emitted.
In the case of Betatron radiation source, the plasmachannel is generated in a pulsed gas jet using highintensity laser pulses. The x-ray radiation is generated bybetatron oscillations of off-axis electrons, see Fig. 2.

Figure 2: Generic layout of generation of x-ray radiationin plasma betatron.
The soft x-ray laser scheme will be based on
amplification of HHG in an additional gas cell, which will
be subsequently amplified in a laser-produced plasma
column. The amplifying plasma column will be generated
by kilojoule-class uncompressed pulses with duration of
0.5 to 3 ns.

Electron Acceleration
The basic electron acceleration setup is intended as atool of investigation for the optimization of a laser-plasma
accelerator (using gas-jet targets, gas-filled capillary, etc.)
by using simple laser wakefield acceleration schemes.
Moreover, novel techniques will also be used to control
the process of electron injection into the wakefield
through density ramps, double-off-axis parabola (shortand long focal length) geometries, etc. The main topic
will be to investigate plasma processes and laser
performances able to improve the quality of the produced
electron beams in order to overcome the present limits.
An advanced configuration will aim at investigating thegeneration of all-optical inverse Compton scattering nearmonochromatic X/Gamma radiation in a counter
propagating double-beam. The same configuration will beeasily adaptable for various experiments which can beproposed by the laser-plasma scientific community, e.g.
“flying mirror” geometry or investigations based on“radiation friction” effects. More sophisticated schemes
will aim at increasing the maximum electron beam energy(mainly through a multi-staged plasma-based accelerator).

Ion Acceleration and ELIMED
In the first phase of the project the Target Normal
Sheath Acceleration (TNSA) mechanism will be
investigated by using micrometer-thick foils with themain goal of reducing shot-to-shot fluctuations anddemonstrating the capability to work in a laser repetition
rate regime (1 Hz). At the same time we aim toexperimentally investigate new target geometries capableto provide much better laser driven proton/ion beam
performances (increase the maximum proton energy andtotal number, and decrease the beam divergence) by using
petawatt-class lasers. For instance, the possibility to apply
structures of scale-lengths comparable with the laser
wavelength (or shorter) on the thin foil surface (enhanced
TNSA) will be investigated. Such laser driven ion beams
will be mainly used for the ELIMED beamline with theISBN 978-3-95450-119-9
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Overview and Commissioning of Facilities

Proceedings of IBIC2012, Tsukuba, Japan
final goal to perform proof-of-principle experiments (in 110 Hz laser regime) which might demonstrate the validityof new approaches for potential future applications in thefield of hadron-therapy.

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displacement of all electrons in a thin (nm scale) foil. In
the latter case few GeV proton beams with quasimonoenergetic features are expected.

Figure 3: A conceptual scheme of one of the developed ELI beamlines (secondary sources) – XFEL demonstrator (fromleft to right): a petawatt-class laser beam is focused into discharged capillary, laser wakefield accelerated electrons arefocused to pass through a set of undulators to induce the self-amplification spontaneous emission (SASE) process.
Image by courtesy of F. Grüner.

EXPERIMENTAL END-STATIONS
Experimental end-stations for applications inmolecular, biomedical and material sciences rely on
synchronized laser, x-ray and charged particle sources.
Several experimental end-stations are being developed
within the ELI project and are mentioned below. It is also
foreseen to provide a beam time to users bringing theirown stations for dedicated experiments. The ELI facility
will be also equipped by dedicated chemical andbiological laboratories available to users to support theabove mentioned and other user experiments.
Ultra-fast pulse radiolysis (PR), Fig. 4, can be inprinciple conducted with sub-picosecond temporal
resolution at the ELI-Beamlines facility. In the Phase 1, a
simple PR workstation will be installed at the K-alphasource beamline, focusing the source radiation on a liquidjet (water) target where it generates transient species andstates. These transient states will be probed by measuring
optical absorption of a synchronized white light flash (andlater on using more sophisticated probes) at a chosen(variable) delay.

Table 1: Summary of Envisioned Parameters of the Secondary Sources
Phase 1 (2015 – 2016)

Phase 2 (2017 – 2019)

Phase 3 (2020 - )Energy range

100 eV - 1 MeV (photons)
0.5-3 GeV (electrons)
20-30 MeV (protons)

100 eV - 5 MeV (photons)
2-5 GeV (electrons)
60-200 MeV (protons)

100 eV - 5 MeV (photons)
2-50 GeV (electrons)
0.1-1 GeV (protons)

Yield per shot

104-106 (photons)
1-100 pC (electrons)
109-1010 (protons)

105-1010 (photons)
1-100 pC (electrons)
1010-1011 (protons)

106-1012 (photons)
1-100 pC (electrons)
1011-1012 (protons)

ISBN 978-3-95450-119-9
Overview and Commissioning of Facilities3

c 2012 by the respective authors — cc Creative Commons Attribution 3.0 (CC BY 3.0)
Copyright ○An important step of ELIMED will be to demonstratethat the laser-accelerated proton beams can reach energyof about 60 MeV with a proton yield (number of protons
per laser pulse) at the output of the beam transport line,
which is sufficient for their application in various fields(mainly radiobiology). A special attention will be devoted
to dosimetry studies aimed to design an alternative
treatment planning for a future application (only proof-ofprinciple) in treatment of eye tumors (60-70MeV, quasimonoenergetic proton beams are needed).
Starting from the second phase of the project (2017and later), when a 10 PW class laser is expected toconsiderably increase the power/intensity on target,
according to numerical particle-in-cell simulations, thepredominant ion acceleration regimes should be: (i)“Shock Acceleration” (for I>1020 W/cm2) through the socalled “hole boring” mechanism at the target front surface
or in its interior; (ii) “Radiation Pressure Acceleration”(for I~1021-1023 W/cm2) when the laser electromagnetic
wave directly accelerates the ions in the target with a very
high efficiency through the space-charge force due to theTUPB57

Proceedings of IBIC2012, Tsukuba, Japanc 2012 by the respective authors — cc Creative Commons Attribution 3.0 (CC BY 3.0)
Copyright ○Stimulated Raman scattering (SRS or FSRS –femtosecond stimulated Raman spectroscopy) will be
used for probing ultra-fast processes initiated by UV-VisNIR pulses or ionizing radiation. This technique yields
information not only on the formation and decay of shortliving species and states, but makes possible detailed
mapping of vibrational energy flows in excited molecules.
In Phase 1, a proof-of-principle SRS experiment isplanned. In Phase 2, it will be possible to integrate theproven SRS probe into particular pump-probe schemes
dealing with ultra-fast dynamics of photo- and radiationinitiated processes in chosen (bio)molecular systems.

Phase 1. In Phase 3, multiple-beam diffractive imaging
experiments will be carried out in the DI workstation.

DETECTOR REQUIREMENTS
All the above outlined laser systems, secondary sourcesand experimental stations will require a wide range of
detectors sensitive to various particles (photons fromoptical down to gamma range, electrons, protons, ions,
neutrons), covering intensities from single particle
counting to the detection of bunches of particles with a
total charge of up to 1 nC, providing outstanding timesynchronization (at the level of femto seconds for
dedicated pump and probe experiments), working at highrepetition rate (1 kHz in some cases) and resistant against
strong electromagnetic pulses (EMP) generated by thesecondary laser driven plasma sources within the vacuum
chambers.
The EMP causes the chambers to ring at their natural
frequencies which can extend from a few MHz to many
GHz. The EMP within the chambers is estimated to beabout 2,500kV/m. The chamber will provide shielding but
allow a significant emission of the EMP throughdiagnostic windows and chamber wiring. The level of
EMP in the experimental halls is estimated to be about
250V/m.

SUMMARY
Figure 4: Scheme of pulse radiolysis layout in Phase 1(2015 – 2016).
Time resolved diffraction end-station will be using
long-wavelength pulse as a pump and X-ray pulse as adiffractive probe. Investigated will be nanocrystalline
samples,superlattices,
crystals,or
flyingmicro/nanoobjects, in which different structural changes(e.g. phase transitions, non-thermal melting, excitation ofcoherent phonons, induced strain propagation) can beinitiated. This technique allows direct probing of thestructural dynamics with 100s fs time resolution and subAngstrom resolution.
Coherent diffractive imaging is a technique that allows
to study structural dynamics of single non-periodic
nanometer-sized objects (e.g. (bio)macromolecules,
viruses, and cells) using a coherent X-ray pulse. The pulse
has to be intense enough for the signal from a single
object to be observable and it has to be short enough (10sfs) so the diffraction image is acquired before the sample
is damaged. Realization of these experiments strictly
depends on the availability of coherent X-ray beams at thefacility. Therefore, the experiment itself (following thecommissioning of the Diffractive imaging (DI)workstation) is planned in the Phase 2/3 of the project(from 2017 on). The key components of the DI
workstation, especially large-area imaging X-ray
detectors, sample injectors and sample state/position
diagnostics, should be developed, built and tested in

We have outlined briefly the laser systems, laser driven
secondary sources of x-ray and charged particle pulses,
experimental stations and detector requirements of the
ELI Beamlines facility, which is to start the first user
operation in 2016. The facility will also provide dedicatedexperiments for plasma, warm dense matter and high field
physics, which is beyond the scope of this short overview.
For more detailed information we refer the kind reader to[1] and [2].

ACKNOWLEDGMENT
This work benefitted from the support of the Czech
Republic’s Ministry of Education, Youth and Sports to
the HiLASE (CZ.1.05/2.1.00/01.0027), ELI-Beamlines(CZ.1.05/1.1.00/483/02.0061)
andOPVK(CZ.1.07/2.3.00/20.0087) projects, and of the Academy of
Sciences of the Czech Republic (Project No.
M100101210).

REFERENCES[1] G. Mourou, G. Korn,W. Sandner, and J.L. Collier.
ELI - Extreme Light Infrastructure: Science andTechnology with Ultra-Intense Lasers Whitebook,2011,
http://old.eli-beams.eu/wpcontent/uploads/2011/10/ELI-Book_neues_Logoedited-web.pdf[2] G. Korn et al: ELI Beamlines – Summary of User
Requirements Specification, to be published in 2012,
http:// http://www.eli-beams.eu/media/documents/

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