1. A Free Electron Laser Project at LNF
Massimo Ferrario
INFN - LNF
& the SPARC/X Team
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2. Synchrotron Radiation Free Electron Laser (FEL)
Outline
Atomic Laser
Synchrotron Radiation
Free Electron Laser (FEL)
SPARC - SPARXINO - SPARX
Applications
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3. Light Amplification by Stimulated Emission of Radiation
Atomic Laser
Light Amplification by Stimulated Emission of Radiation
Spontaneous Emission
Stimulated Emission
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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.
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5. prova

6. 1. Well known and proven technology. 2. One Laser One Color.
Atomic Laser
1. Well known and proven technology.
2. One Laser One Color.
3. Limited by Mirrors ==> No X rays.
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7. Cosmic MASER

8. Synchrotron Radiation
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9. Charged particle moving on a circle
Radiation Simulator – T.
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10. Pulse Duration
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11. Cut-Off Frequency of the Spectrum
Revolution Frequency N
Cut-Off Frequency of the Spectrum
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12. prova

13. Undulator Radiation
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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
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15. Relativistic Mirrors TUNABILITY Counter propagating pseudo-radiation
Compton back-scattered radiation in the moving mirror frame
Doppler effect in the laboratory frame
TUNABILITY
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16. Radiation Simulator – T. Shintake, @ http://www-xfel. spring8. or
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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
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18. Spectral Intensity
Line width
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19. WE NEED micro-BUNCHING !
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 !
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20. prova

21. High Gain FEL
Consider“seeding”by 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
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22. if the flight time delay is exactly one radiation period:
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
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23. Newton Lorentz Equations
Question: can there be a continuous energy transfer from electron beam to light wave?
Answer: We need a Self Consistent Treatment
Newton Lorentz Equations
Maxwell Equations
l /2
t>0
t=0
Optical
potential
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24. Result: collective instability, exponential growth of radiation power.
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
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25. SASE Saturation Results
LEUTL
APS/ANL
385 nm
September 2000
Since September 2000:
3 SASE FEL’s demonstrate saturation
TTF-FEL
DESY
98 nm
VISA
ATF/BNL
840 nm
March 2001
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26. TTF FEL
LEUTLE
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27. SASE Longitudinal coherenceζ
independent
processes
Slippage length 
The radiation “slips” over the electrons for a distance Nurad
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28. SASE
Courtesy L. Giannessi (Perseo in 1D mode
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30. SEEDING
Courtesy L. Giannessi (Perseo in 1D mode
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33. High Brightness Electron Beams
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34. Linear Accelerators PRINCIPIO:
Le particelle emesse da un filamento vengono accelerate dal campo elettrico longitudinale generato da elettrodi susseguenti.
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35. Linear Radio-Frequency Accelerators
fascio
Campo elettrico
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36. Electron Photo-Injector
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37. SPARC - SPARXINO - SPARX
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39. GENESIS simulation of the SPARC SASE-FEL
Radiation power growth along the 530 nm
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40. SPARC
DESY
BNL
UCLA
SLAC UE
MOU
EUROFEL
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42. SPARC Injector + DAFNE Linac a <10 nm SASE FEL source at LNF
SPARXINO
a <10 nm SASE FEL source at LNF
Energy [GeV]
cr
[nm]
I = 1 kA
K = 3
e = 0.1 %
n=4
n=1
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43. The FEL Applications
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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
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45. Free Electron Lasers: applicazioni
diminuire la lunghezza d’onda
(λ-> raggi X)
Impulsi ultra-corti
aumentare potenza media
(per λ nell’ IR-UV)
Applicazioni mediche e industriali
Struttura della materia,ad es. Dinamica delle molecole, reazioni chimiche
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46. used spark photography to freeze this ‘ultra-fast’ process
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).
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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.
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49. X-FEL based on last 1-km of existing SLAC linac
LCLS at SLAC Å
X-FEL based on last 1-km of existing SLAC linac
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50. TESLA XFEL at DESY 0.85-60 Å X-FEL Integrated into linear collider
user facility Å
multiple undulators
X-FEL Integrated into linear collider
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52. THE END