A Free Electron Laser Project at LNF Massimo Ferrario INFN - LNF & the SPARC/X Team prova
Synchrotron Radiation Free Electron Laser (FEL) Outline Atomic Laser Synchrotron Radiation Free Electron Laser (FEL) SPARC - SPARXINO - SPARX Applications prova
Light Amplification by Stimulated Emission of Radiation Atomic Laser Light Amplification by Stimulated Emission of Radiation Spontaneous Emission Stimulated Emission prova
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. prova
prova
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. prova
Cosmic MASER
Synchrotron Radiation prova
Charged particle moving on a circle Radiation Simulator – T. Shintake, @ http://www-xfel.spring8.or.jp/Index.htm prova
Pulse Duration prova
Cut-Off Frequency of the Spectrum Revolution Frequency N Cut-Off Frequency of the Spectrum prova
prova
Undulator Radiation prova
Undulator Radiation The electron trajectory is determined by the undulator field and the electron energy The electron trajectory is inside the radiation cone if prova
Relativistic Mirrors TUNABILITY Counter propagating pseudo-radiation Compton back-scattered radiation in the moving mirror frame Doppler effect in the laboratory frame TUNABILITY prova
Radiation Simulator – T. Shintake, @ http://www-xfel. spring8. or prova
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 prova
Spectral Intensity Line width prova
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 ! prova
prova
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 prova
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 prova
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 prova
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 prova
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 prova
TTF FEL LEUTLE prova
SASE Longitudinal coherence ζ independent processes Slippage length The radiation “slips” over the electrons for a distance Nurad prova
SASE Courtesy L. Giannessi (Perseo in 1D mode http://www.perseo.enea.it) prova
prova
SEEDING Courtesy L. Giannessi (Perseo in 1D mode http://www.perseo.enea.it) prova
prova
prova
High Brightness Electron Beams prova
Linear Accelerators PRINCIPIO: Le particelle emesse da un filamento vengono accelerate dal campo elettrico longitudinale generato da elettrodi susseguenti. prova
Linear Radio-Frequency Accelerators fascio Campo elettrico prova
Electron Photo-Injector prova
SPARC - SPARXINO - SPARX prova
prova
GENESIS simulation of the SPARC SASE-FEL Radiation power growth along the undulator @ 530 nm prova
SPARC DESY BNL UCLA SLAC UE MOU EUROFEL prova
prova
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 prova
The FEL Applications prova
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 prova
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 prova
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). prova
prova
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. prova
X-FEL based on last 1-km of existing SLAC linac LCLS at SLAC 1.5-15 Å X-FEL based on last 1-km of existing SLAC linac prova
TESLA XFEL at DESY 0.85-60 Å X-FEL Integrated into linear collider user facility 0.85-60 Å multiple undulators X-FEL Integrated into linear collider prova
prova
THE END