a source for coherent radiation production in the soft x-ray energy range the sparx fel project
TRANSCRIPT
a source for coherent radiation production in the soft X-ray
energy range
The SPARX FEL ProjectThe SPARX FEL Project
Main components of a Free Electron Laser • an accelerator providing a bunched relativistic electron beam• an undulator magnetElectrons 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 usedAt 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 ‘s
The Principle of Self-Amplified Spontaneous Emission (SASE) X-FELs
Sparx
X-FEL ~ 0.1 nm 2013
Fermi1 100 40 nm 2010
Fermi2 40 10 nm 2011
SPARX 13 1 nm 2013
SPARC 500 100 nmcommissioning
FLASH 13 6.5 nm in operation
100 nm ≈ 12 eVh=6.6x10-34 J.s = 4.1 x 10 -15 eV.sh = 12 eV= 12 eV/h ≈ 3 x 10 15 s-1
= c/= 3 x 10 8ms-1/ 3 x 10 15 s-1= 10 -7 m = 100 nm= [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
UK
GE
IT
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ITCH
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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.
Neutze et al. Nature (2000) 406:752
X-ray intensity, I(t) = 3 x 1012 (12 keV~1Å) photons per 100-nm diameter spot (3.8 x 106 photons per Å2)
Explosion of T4 Lysozyme
= [h(eV.s).c]/E(eV)=(12.4 x 10 -7eV.m)/E(eV)
Reconstructed image
No sign of radiation damage
Diffraction pattern from the
subsequent pulse
The first pulse destroyed the object after recording the
image
CCD detector recording a continuous
diffraction pattern
A coherent diffraction pattern of
the object
recorded from a single
25-femtosecond FEL pulse
K.J. Gaffney, H.N. Chapman Science 316, 1444 (2007)
Schematic depiction of single-particle coherent diffractive imaging with an XFEL pulse
plasma formation
Coulomb explosion
3D diffraction data set is assembled from noisy diffraction patterns of identical particles in random and unknown
orientations.
The image is then obtained by phase
retrieval
Fourier amplitude of (a) + Fourier phases of (b)
Fourier amplitude of (b) + Fourier phases of (a)
The Importance of the Phase Information
(a) (b)
A Scanning ElectronMicroscopy image
An oversampled diffraction pattern
Image reconstructed from (b)
Miao, Charalambous, Kirz & Sayre, Nature 400, 342 (1999).
The First Experimental Demonstration
(c)
(a) (b)
Henry Chapman: Flash Diffraction Imaging of Biological Samples
FLASH: 45 proposals 32 approved
Tor Vergata FEL colloquiaMarch, 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) MiaoDepartment 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”