A1261834213CnlAV

1
A Free Electron Laser Project at LNF Massimo
Ferrario INFN - LNF the SPARC/X Team
2
Outline
Atomic Laser Synchrotron Radiation Free Electron
Laser (FEL) SPARC - SPARXINO - SPARX Applications
3
Atomic Laser Light Amplification by Stimulated
Emission of Radiation
Spontaneous Emission
Stimulated Emission
4
Properties of Stimulated Emission The photon
which is emitted in the stimulated emission
process is identical to the incoming
photon. They both have 1. Identical
wavelengths - Monochromaticity. 2. Identical
directions in space - Directionality. 3.
Identical phase - Coherence.
5
(No Transcript)
6
Atomic Laser 1. Well known and proven
technology. 2. One Laser One Color. 3.
Limited by Mirrors gt No X rays.
7
Cosmic MASER
8
Synchrotron Radiation
9
Charged particle moving on a circle
Radiation Simulator T. Shintake, _at_
http//www-xfel.spring8.or.jp/Index.htm
10
Pulse Duration
11
Revolution Frequency
N?
Cut-Off Frequency of the Spectrum
12
(No Transcript)
13
Undulator Radiation
14
Undulator Radiation
The electron trajectory is determined by the
undulator field and the electron energy
The electron trajectory is inside the radiation
cone if
15
Relativistic Mirrors
Counter propagating pseudo-radiation
Compton back-scattered radiation in the moving
mirror frame
Doppler effect in the laboratory frame
TUNABILITY
16
Radiation Simulator T. Shintake, _at_
http//www-xfel.spring8.or.jp/Index.htm
17
Nu 5





Due to the finite duration the radiation is not
monochromatic but contains a frequency spectrum
which is obtained by Fourier transformation of a
truncated plane wave
18
Spectral Intensity
Line width
19
Peak power of accelerated charge
different electrons radiate indepedently hence
the total power depends linearly on the number Ne
of electrons per bunch
Incoherent Spontaneous Radiation Power
Coherent Stimulated Radiation Power
WE NEED micro-BUNCHING !
20
(No Transcript)
21
High Gain FEL
Considerseedingby an external light source with
wavelength ?r The light wave is co-propagating
with the relativistic electron beam
Energy exchange occurs only if there is
transverse motion
22
After one wiggler period the electron sees the
radiation with the same phase if the flight time
delay is exactly one radiation period
In a resonant and randomly phased electron beam,
nearly one half electrons absorb energy and half
lose enrgy, with no net gain The particles bunch
around a phase for which there is no coupling
with the radiation
23
Question can there be a continuous energy
transfer from electron beam to light wave?
Answer We need a Self Consistent Treatment
24
The electron beam acts as a dielectric medium
which slows down the phase velocity of the
ponderomotive field compared to the average
electron longitudinal velocity. Hence resonant
electrons bunch around a phase corresponding to
gain.
The particles within a micro-bunch radiate
coherently. The resulting strong radiationfield
enhances the micro-bunching even further.
Result collective instability, exponential
growth of radiation power. Even if there is no
external seeding Self Amplified Spontaneous
Emission
25
SASE Saturation Results
Since September 2000 3 SASE FELs demonstrate
saturation
26
(No Transcript)
27
SASE Longitudinal coherence
The radiation slips over the electrons for a
distance Nu?rad
28
SASE
Courtesy L. Giannessi (Perseo in 1D mode
http//www.perseo.enea.it)
29
(No Transcript)
30
SEEDING
Courtesy L. Giannessi (Perseo in 1D mode
http//www.perseo.enea.it)
31
(No Transcript)
32
(No Transcript)
33
High Brightness Electron Beams
34
Linear Accelerators
PRINCIPIO Le particelle emesse da un filamento
vengono accelerate dal campo elettrico
longitudinale generato da elettrodi susseguenti.
35
Linear Radio-Frequency Accelerators
36
Electron Photo-Injector
37
SPARC - SPARXINO - SPARX
38
(No Transcript)
39
GENESIS simulation of the SPARC SASE-FEL
Radiation power growth along the undulator _at_ 530
nm
40
(No Transcript)
41
(No Transcript)
42
SPARC Injector DAFNE Linac SPARXINO a lt10 nm
SASE FEL source at LNF
43
The FEL Applications
44
Scientific case new research frontiers in

• Atomic, molecular and cluster physics
• Plasma and warm dense matter
• Condensed matter physics
• Material science
• Femtosecond chemistry
• Life science
• Single Biological molecules and clusters
• Imaging/holography
• Micro and nano lithography
• Short Pulses

45
Free Electron Lasers applicazioni
aumentare potenza media (per ? nell IR-UV)
diminuire la lunghezza donda (?-gt raggi
X) Impulsi ultra-corti
Applicazioni mediche e industriali
Struttura della materia,ad es. Dinamica delle
molecole, reazioni chimiche
46
E. Muybridge at L. Stanford in 1878
disagree whether all feet leave the ground during
gallop
E. Muybridge
used spark photography to freeze this
ultra-fast process
E. Muybridge, Animals in Motion, ed. L. S. Brown
(Dover Pub. Co., New York 1957) Courtesy Paul
Emma (SLAC).
47
(No Transcript)
48
Coulomb Explosion of Lysozyme (50 fs)
Single Molecule Imaging with Intense X-rays
Atomic and molecular dynamics occur at the
fsec-scale
J. Hajdu, Uppsala U.
49
LCLS at SLAC
1.5-15 Å
X-FEL based on last 1-km of existing SLAC linac
50
TESLA XFEL at DESY
0.85-60 Å
multiple undulators
X-FEL Integrated into linear collider
51
(No Transcript)
52
THE END