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Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant
Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron Notkestraße 85, DE-22607 Hamburg, Germany.
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2007 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 98, no 14, 145502- p.Article in journal (Refereed) Published
Abstract [en]

At the recently built FLASH x-ray free-electron laser, we studied the reflectivity of Si/C multilayers with fluxes up to 3×1014W/cm2. Even though the nanostructures were ultimately completely destroyed, we found that they maintained their integrity and reflectance characteristics during the 25-fs-long pulse, with no evidence for any structural changes over lengths greater than 3Å. This experiment demonstrates that with intense ultrafast pulses, structural damage does not occur during the pulse, giving credence to the concept of diffraction imaging of single macromolecules.

Place, publisher, year, edition, pages
2007. Vol. 98, no 14, 145502- p.
Keyword [en]
X-ray effects, Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
National Category
Biological Sciences Physical Sciences
URN: urn:nbn:se:uu:diva-96325DOI: 10.1103/PhysRevLett.98.145502ISI: 000245512100037OAI: oai:DiVA.org:uu-96325DiVA: diva2:170864

Available from: 2007-10-24 Created: 2007-10-24 Last updated: 2016-04-12Bibliographically approved
In thesis
1. Interaction of Ultrashort X-ray Pulses with Material
Open this publication in new window or tab >>Interaction of Ultrashort X-ray Pulses with Material
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Radiation damage limits the resolution in imaging experiments. Damage is caused by energy deposited into the sample during exposure. Ultrashort and extremely bright X-ray pulses from free-electron lasers (FELs) offer the possibility to outrun key damage processes, and temporarily improve radiation tolerance. Theoretical models indicate that high detail-resolutions could be realized on non-crystalline samples with very short pulses, before plasma expansion.

Studies presented here describe the interaction of a very intense and ultrashort X-ray pulse with material, and investigate boundary conditions for flash diffractive imaging both theoretically and experimentally. In the hard X-ray regime, predictions are based on particle simulations with a continuum formulation that accounts for screening from free electrons.

First experimental results from the first soft X-ray free-electron laser, the FLASH facility in Hamburg, confirm the principle of flash imaging, and provide the first validation of our theoretical models. Specifically, experiments on nano-fabricated test objects show that an interpretable image can be obtained to high resolution before the sample is vaporized. Radiation intensity in these experiments reached 10^14 W/cm^2, and the temperature of the sample rose to 60000 Kelvin after the 25 femtosecond pulse left the sample. Further experiments with time-delay X-ray holography follow the explosion dynamics over some picoseconds after illumination.

Finally, this thesis presents results from biological flash-imaging studies on living cells. The model is based on plasma calculations and fluid-like motions of the sample, supported by the time-delay measurements. This study provides an estimate for the achievable resolutions as function of wavelength and pulse length. The technique was demonstrated by our team in an experiment where living cells were exposed to a single shot from the FLASH soft X-ray laser.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2007. 76 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 356
free-electron laser, dense plasma, X-ray, radiation damage, laser physics, nano-plasma, Molecular Dynamics
National Category
urn:nbn:se:uu:diva-8274 (URN)978-91-554-6996-2 (ISBN)
Public defence
2007-11-15, B41, BMC, Husargatan 3, Uppsala, 09:00
Available from: 2007-10-24 Created: 2007-10-24Bibliographically approved

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