The SPARX FEL Project a source for coherent radiation production in the soft X-ray energy range

Main components of a Free Electron Laser an accelerator providing a bunched relativistic electron beam an undulator magnet Electrons are not bound in atomic, molecular or solid-state levels but are moving freely in vacuum For visible or infrared light an optical resonator can be used At l below 100 nm the reflectivity of metals and other mirror coatings drops quickly to zero at normal incidence. The principle of Self-Amplifified Spontaneous Emission (SASE) allows the realization of high-gain FELs at these short l‘s

The Principle of Self-Amplified Spontaneous Emission (SASE) X-FELs

Sparx

SPARC 500  100 nm commissioning FLASH 13  6.5 nm in operation X-FEL ~ 0.1 nm 2013 Fermi1 100  40 nm 2010 Fermi2 40  10 nm 2011 SPARX 13  1 nm 2013 SPARC 500  100 nm commissioning FLASH 13  6.5 nm in operation 100 nm ≈ 12 eV h=6.6x10-34 J.s = 4.1 x 10 -15 eV.s hn = 12 eV = 12 eV/h ≈ 3 x 10 15 s-1 l = c/n = 3 x 10 8ms-1/ 3 x 10 15 s-1= 10 -7 m = 100 nm l = [h(eV.s).c]/E(eV)=(12.4 x 10 -7eV.m)/E(eV)

Peak brightness (brilliance) versus pulse duration of various types of radiation sources

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Free-electron laser used in human brain/eye surgery Use of the FEL to help remove a tumor from the brain of a patient. Unlike conventional lasers that produce light at given wavelengths, the FEL beam can be tuned through a wide spectrum of colors. That has allowed researchers to find the optimal wavelength (6.45µm) for cutting cleanly through living tissue. Free-electron laser used in human brain/eye surgery

Explosion of T4 Lysozyme X-ray intensity, I(t) = 3 x 1012 (12 keV~1Å) photons per 100-nm diameter spot (3.8 x 106 photons per Å2) Neutze et al. Nature (2000) 406:752

l = [h(eV.s).c]/E(eV)=(12.4 x 10 -7eV.m)/E(eV)

CCD detector recording a continuous diffraction pattern A coherent diffraction pattern of the object recorded from a single 25-femtosecond FEL pulse Diffraction pattern from the subsequent pulse Reconstructed image No sign of radiation damage The first pulse destroyed the object after recording the image

The image is then obtained by phase retrieval Schematic depiction of single-particle coherent diffractive imaging with an XFEL pulse K.J. Gaffney, H.N. Chapman Science 316, 1444 (2007) plasma formation Coulomb explosion The image is then obtained by phase retrieval 3D diffraction data set is assembled from noisy diffraction patterns of identical particles in random and unknown orientations.

The Importance of the Phase Information (b) Fourier amplitude of (a) + Fourier phases of (b) Fourier amplitude of (b) + Fourier phases of (a)

The First Experimental Demonstration (b) A Scanning Electron Microscopy image An oversampled diffraction pattern (c) Miao, Charalambous, Kirz & Sayre, Nature 400, 342 (1999). Image reconstructed from (b)

Flash Diffraction Imaging of Biological Samples FLASH: 45 proposals 32 approved Henry Chapman: Flash Diffraction Imaging of Biological Samples

Tor Vergata FEL colloquia March, 19, 2008 – Prof. Giorgio Margaritondo Ecole Polytechnique Fédérale de Lausanne, Switzerland   "Coherent Radiology - from Synchrotrons to Free Electron Lasers" Aprile, 2, 2008 – Prof. Jianwei (John) Miao Department of Physics and Astronomy, Univ. of California, USA   "Coherent Scattering, Oversampling and Applications of X-ray Free Electron Lasers" April, 23, 2008 – Prof. Janos Hajdu Structural Biology Labs Biomedical Centre, Uppsala, Sweden “TBA” June, 18, 2008 – Prof. Massimo Altarelli  European X-ray Free-Electron Laser Project Team, DESY,Germany “The European X-ray Free-Electron Laser Project in Hamburg”