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1 A Free Electron Laser Project at LNF Massimo Ferrario INFN - LNF & the SPARC/X Team.

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Presentation on theme: "1 A Free Electron Laser Project at LNF Massimo Ferrario INFN - LNF & the SPARC/X Team."— Presentation transcript:

1 1 A Free Electron Laser Project at LNF Massimo Ferrario INFN - LNF & the SPARC/X Team

2 2 Atomic Laser Synchrotron Radiation Free Electron Laser (FEL) SPARC - SPARXINO - SPARX Applications Outline

3 3 Atomic Laser Light Amplification by Stimulated Emission of Radiation Spontaneous Emission Stimulated Emission

4 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 5

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

7 7 Cosmic MASER

8 8 Synchrotron Radiation

9 9 Charged particle moving on a circle Radiation Simulator – T.

10 10 Pulse Duration

11 11 Cut-Off Frequency of the Spectrum Revolution Frequency N

12 12

13 13 Undulator Radiation

14 14 Undulator Radiation The electron trajectory is inside the radiation cone if The electron trajectory is determined by the undulator field and the electron energy

15 15 Relativistic Mirrors Counter propagating pseudo-radiation Compton back-scattered radiation in the moving mirror frame Doppler effect in the laboratory frame TUNABILITY

16 16 Radiation Simulator – T.

17 17 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 N u = 5 {{ { {{

18 18 Spectral Intensity Line width

19 19 Peak power of accelerated charge: different electrons radiate indepedently hence the total power depends linearly on the number N e of electrons per bunch: Incoherent Spontaneous Radiation Power: Coherent Stimulated Radiation Power: WE NEED micro-BUNCHING !

20 20

21 21 High Gain FEL Energy exchange occurs only if there is transverse motion Considerseedingby an external light source with wavelength r The light wave is co-propagating with the relativistic electron beam

22 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 23 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 /2 t>0 t=0 Optical potential

24 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 25 SASE Saturation Results TTF-FEL DESY 98 nm TTF-FEL DESY 98 nm Since September 2000: 3 SASE FELs demonstrate saturation Since September 2000: 3 SASE FELs demonstrate saturation LEUTL APS/ANL 385 nm LEUTL APS/ANL 385 nm September 2000 VISA ATF/BNL 840 nm VISA ATF/BNL 840 nm March 2001


27 27 SASE Longitudinal coherence The radiation slips over the electrons for a distance N u rad ζ independent processes Slippage length

28 28 SASE Courtesy L. Giannessi (Perseo in 1D mode

29 29

30 30 SEEDING Courtesy L. Giannessi (Perseo in 1D mode

31 31

32 32

33 33 High Brightness Electron Beams

34 34 Linear Accelerators PRINCIPIO: Le particelle emesse da un filamento vengono accelerate dal campo elettrico longitudinale generato da elettrodi susseguenti.

35 35 fascio Campo elettrico Linear Radio-Frequency Accelerators

36 36 Electron Photo-Injector


38 38

39 39 Radiation power growth along the 530 nm GENESIS simulation of the SPARC SASE-FEL


41 41

42 42 Energy [GeV] cr [nm] I = 1 kA K = 3 e = 0.1 % e = 0.1 % n =4 n =4 n =1 n =1 SPARC Injector + DA NE Linac SPARXINO a <10 nm SASE FEL source at LNF

43 43 The FEL Applications

44 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 45 Free Electron Lasers: applicazioni aumentare potenza media (per λ nell IR-UV) Applicazioni mediche e industriali diminuire la lunghezza donda (λ-> raggi X) Impulsi ultra-corti Struttura della materia,ad es. Dinamica delle molecole, reazioni chimiche

46 46 E. Muybridge at L. Stanford in 1878 E. Muybridge, Animals in Motion, ed. L. S. Brown (Dover Pub. Co., New York 1957) Courtesy Paul Emma (SLAC). used spark photography to freeze this ultra-fast process E. Muybridge disagree whether all feet leave the ground during gallop…

47 47

48 48 Coulomb Explosion of Lysozyme (50 fs) J. Hajdu, Uppsala U. Atomic and molecular dynamics occur at the fsec-scale Single Molecule Imaging with Intense X-rays

49 49 X-FEL based on last 1-km of existing SLAC linac LCLS at SLAC Å

50 50 TESLA XFEL at DESY X-FEL Integrated into linear collider Å user facility multiple undulators

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