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Iwan, Bianca
Alternative names
Publications (6 of 6) Show all publications
Ekeberg, T., Svenda, M., Seibert, M. M., Abergel, C., Maia, F. R. .., Seltzer, V., . . . Hajdu, J. (2016). Single-shot diffraction data from the Mimivirus particle using an X-ray free-electron laser. Scientific Data, 3, Article ID UNSP 160060.
Open this publication in new window or tab >>Single-shot diffraction data from the Mimivirus particle using an X-ray free-electron laser
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2016 (English)In: Scientific Data, E-ISSN 2052-4463, Vol. 3, article id UNSP 160060Article in journal (Refereed) Published
Abstract [en]

Free-electron lasers (FEL) hold the potential to revolutionize structural biology by producing X-ray pules short enough to outrun radiation damage, thus allowing imaging of biological samples without the limitation from radiation damage. Thus, a major part of the scientific case for the first FELs was three-dimensional (3D) reconstruction of non-crystalline biological objects. In a recent publication we demonstrated the first 3D reconstruction of a biological object from an X-ray FEL using this technique. The sample was the giant Mimivirus, which is one of the largest known viruses with a diameter of 450 nm. Here we present the dataset used for this successful reconstruction. Data-analysis methods for single-particle imaging at FELs are undergoing heavy development but data collection relies on very limited time available through a highly competitive proposal process. This dataset provides experimental data to the entire community and could boost algorithm development and provide a benchmark dataset for new algorithms.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-314814 (URN)10.1038/sdata.2016.60 (DOI)000390225400005 ()
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationEU, European Research CouncilStiftelsen Olle Engkvist Byggmästare
Available from: 2017-02-07 Created: 2017-02-06 Last updated: 2017-11-29Bibliographically approved
Iwan, B. (2012). Creating and Probing Extreme States of Materials: From Gases and Clusters to Biosamples and Solids. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Creating and Probing Extreme States of Materials: From Gases and Clusters to Biosamples and Solids
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Free-electron lasers provide high intensity pulses with femtosecond duration and are ideal tools in the investigation of ultrafast processes in materials. Illumination of any material with such pulses creates extreme conditions that drive the sample far from equilibrium and rapidly convert it into high temperature plasma. The dynamics of this transition is not fully understood and the main goal of this thesis is to further our knowledge in this area.

We exposed a variety of materials to X-ray pulses of intensities from 1013 to above 1017 W/cm2. We found that the temporal evolution of the resulting plasmas depends strongly on the wavelength and pulse intensity, as well as on material related parameters, such as size, density, and composition.

In experiments on atomic and molecular clusters, we find that cluster size and sample composition influence the destruction pathway. In small clusters a rapid Coulomb explosion takes place while larger clusters undergo a hydrodynamic expansion. We have characterized this transition in methane clusters and discovered a strong isotope effect that promotes the acceleration of deuterium ions relative to hydrogen. Our results also show that ions escaping from exploding xenon clusters are accelerated to several keV energies.

Virus particles represent a transition between hetero-nuclear clusters and complex biological materials. We injected single mimivirus particles into the pulse train of an X-ray laser, and recorded coherent diffraction images simultaneously with the fragmentation patterns of the individual particles. We used these results to test theoretical damage models. Correlation between the diffraction patterns and sample fragmentation shows how damage develops after the intense pulse has left the sample.

Moving from sub-micron objects to bulk materials gave rise to new phenomena. Our experiments with high-intensity X-ray pulses on bulk, metallic samples show the development of a transient X-ray transparency. We also describe the saturation of photoabsorption during ablation of vanadium and niobium samples.

Photon science with extremely strong X-ray pulses is in its infancy today and will require much more effort to gain more knowledge. The work described in this thesis represents some of the first results in this area.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. p. 66
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 975
Keywords
free-electron laser, ultrashort X-rays, non-equilibrium plasma, Coulomb explosion, isotope effect, hydrodynamic expansion, ion acceleration, high intensity lasers, ablation, time-of-flight spectroscopy
National Category
Biophysics
Research subject
Physics
Identifiers
urn:nbn:se:uu:diva-180997 (URN)978-91-554-8477-4 (ISBN)
Public defence
2012-11-09, A1:107, Biomedical Center (BMC), Husargatan 3, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2012-10-17 Created: 2012-09-14 Last updated: 2013-01-23Bibliographically approved
Iwan, B., Andreasson, J., Bergh, M., Schorb, S., Thomas, H., Rupp, D., . . . Timneanu, N. (2012). Explosion, ion acceleration and molecular fragmentation of methane clusters in the pulsed beam of a free-electron laser. Physical Review A. Atomic, Molecular, and Optical Physics, 86(3), 033201
Open this publication in new window or tab >>Explosion, ion acceleration and molecular fragmentation of methane clusters in the pulsed beam of a free-electron laser
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2012 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 86, no 3, p. 033201-Article in journal (Refereed) Published
Abstract [en]

X-ray lasers offer new possibilities for creating and probing extreme states of matter. We used intense and short x-ray pulses from the FLASH soft x-ray laser to trigger the explosions of CH4 and CD4 molecules and their clusters. The results show that the explosion dynamics depends on cluster size and indicate a transition from Coulomb explosion to hydrodynamic expansion in larger clusters. The explosion of CH4 and CD4 clusters shows a strong isotope effect: The heavier deuterons acquire higher kinetic energies than the lighter protons. This may be due to an extended inertial confinement of deuterons vs. protons near a rapidly charging cluster core during exposure.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-180987 (URN)10.1103/PhysRevA.86.033201 (DOI)000308286600008 ()
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2017-12-07Bibliographically approved
Thomas, H., Helal, A., Hoffmann, K., Kandadai, N., Keto, J., Andreasson, J., . . . Ditmire, T. (2012). Explosions of Xenon Clusters in Ultraintense Femtosecond X-Ray Pulses from the LCLS Free Electron Laser. Physical Review Letters, 108(13), Article ID 133401.
Open this publication in new window or tab >>Explosions of Xenon Clusters in Ultraintense Femtosecond X-Ray Pulses from the LCLS Free Electron Laser
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2012 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 108, no 13, article id 133401Article in journal (Refereed) Published
Abstract [en]

Explosions of large Xe clusters (< N > similar to 11 000) irradiated by femtosecond pulses of 850 eV x-ray photons focused to an intensity of up to 1017 W/cm(2) from the Linac Coherent Light Source were investigated experimentally. Measurements of ion charge-state distributions and energy spectra exhibit strong evidence for the formation of a Xe nanoplasma in the intense x-ray pulse. This x-ray produced Xe nanoplasma is accompanied by a three-body recombination and hydrodynamic expansion. These experimental results appear to be consistent with a model in which a spherically exploding nanoplasma is formed inside the Xe cluster and where the plasma temperature is determined by photoionization heating.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-180993 (URN)10.1103/PhysRevLett.108.133401 (DOI)000302019600004 ()22540697 (PubMedID)
Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2017-12-07Bibliographically approved
Iwan, B. S., Andreasson, J., Andrejczuk, A., Abreu, E., Bergh, M., Caleman, C., . . . Timneanu, N. (2011). TOF-OFF: A method for determining focal positions in tightly focused free-electron laser experiments by measurement of ejected ions. High Energy Density Physics, 7(4), 336-342
Open this publication in new window or tab >>TOF-OFF: A method for determining focal positions in tightly focused free-electron laser experiments by measurement of ejected ions
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2011 (English)In: High Energy Density Physics, ISSN 1574-1818, Vol. 7, no 4, p. 336-342Article in journal (Refereed) Published
Abstract [en]

Pulse intensities greater than 1017 Watt/cm2 were reached at the FLASH soft X-ray laser in Hamburg, Germany, using an off-axis parabolic mirror to focus 15 fs pulses of 5–70 μJ energy at 13.5 nm wavelength to a micron-sized spot. We describe the interaction of such pulses with niobium and vanadium targets and their deuterides. The beam produced craters in the solid targets, and we measured the kinetic energy of ions ejected from these craters. Ions with several keV kinetic energy were observed from craters approaching 5 μm in depth when the sample was at best focus. We also observed the onset of saturation in both ion acceleration and ablation with pulse intensities exceeding 1016 W/cm2, when the highest detected ion energies and the crater depths tend to saturate with increasing intensity.

A general difficulty in working with micron and sub-micron focusing optics is finding the exact focus of the beam inside a vacuum chamber. Here we propose a direct method to measure the focal position to a resolution better than the Rayleigh length. The method is based on the correlation between the energies of ejected ions and the physical dimensions of the craters. We find that the focus position can be quickly determined from the ion time-of-flight (TOF) data as the target is scanned through the expected focal region. The method does not require external access to the sample or venting the vacuum chamber. Profile fitting employed to analyze the TOF data can extend resolution beyond the actual scanning step size.

Keywords
X-ray free-electron laser, FLASH, Ion acceleration, Time-of-flight ion spectrometry, Ablation, Crater formation, Focus determination
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-166857 (URN)10.1016/j.hedp.2011.06.008 (DOI)000298040400020 ()
Available from: 2012-01-17 Created: 2012-01-16 Last updated: 2016-04-12Bibliographically approved
Nelson, A. J., Toleikis, S., Chapman, H., Bajt, S., Krzywinski, J., Chalupsky, J., . . . Lee, R. W. (2009). Soft x-ray free electron laser microfocus for exploring matter under extreme conditions. Optics Express, 17(20), 18271-18278
Open this publication in new window or tab >>Soft x-ray free electron laser microfocus for exploring matter under extreme conditions
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2009 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 17, no 20, p. 18271-18278Article in journal (Refereed) Published
Abstract [en]

We have focused a beam (BL3) of FLASH (Free-electron LASer in Hamburg: lambda = 13.5 nm, pulse length 15 fs, pulse energy 10-40 mu J, 5Hz) using a fine polished off-axis parabola having a focal length of 270 mm and coated with a Mo/Si multilayer with an initial reflectivity of 67% at 13.5 nm. The OAP was mounted and aligned with a picomotor controlled six-axis gimbal. Beam imprints on poly(methyl methacrylate) -PMMA were used to measure focus and the focused beam was used to create isochoric heating of various slab targets. Results show the focal spot has a diameter of <= 1 mu m. Observations were correlated with simulations of best focus to provide further relevant information.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-111992 (URN)10.1364/OE.17.018271 (DOI)000270295300112 ()1094-4087 (ISBN)
Available from: 2010-01-05 Created: 2010-01-05 Last updated: 2017-12-12Bibliographically approved
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