Stanford

  • Coherent diffraction of Rice Dwarf virus at the Linac Coherent Light Source

    nature data cover

    In this study, we've applied coherent diffractive imaging to study the structure of a single Rice dwarf virus. The CXI instrument at the Linac coherent light source focuses 1012 photons into a nanometer-sized area. Here the X-rays scatter of a single virus particle and create a snapshot of the virus. The acquired dataset of this study has been published in Nature scientific data, that allows access to the actual dataset. The publication yields information on how to access the data and background information as well. This result comes out of a large collaboration, the Single particle initiative, where scientists from around the world have united to pull on one string and push the method of Single particle imaging to the next level.

    Read more

  • Dual crystal x-ray spectrometer at 1.8 keV for high repetition-rate single-photon counting spectroscopy experiments

    dual crystal spectrometer Journal of Instrumentation, Volume 11
    E.J. Gamboa, B. Bachmann, D. Kraus, M.J. MacDonald, M. Bucher, S. Carron, R.N. Coffee, R.P. Drake, J. Emig, K.R. Ferguson, L.B. Fletcher, S.H. Glenzer, T. Gorkhover, S.P. Hau-Riege, J. Krzywinski, A.L. Levitan, K.-H. Meiwes-Broer, T. Osipov, T. Pardini, C. Peltz, S. Skruszewicz, C. Bostedt, T. Fennel and T. Döppner
    Published 22 August 2016

  • Femtosecond response of polyatomic molecules to ultra-intense hard X-rays

    (DESY/Science Communication Lab)

    The study of molecules with X-rays is of particular interest for biological and potentially pharmaceutical sciences. X-rays are here being used to resolve the shape or structure of a molecule. But when the X-rays interact with the molecules, the ionize the atoms the molecule consists of and the molecule is transformed into a nanoplasma. Such radiation damage is of particular interest, as a solid understanding of the underlying damaging processes is required to lead to high-res imaging. In the linked study that has been published in Nature, we investigate molecules using intense hard X-rays from the CXI instrument at LCLS reaching a never before seen level of ionization. The insights of this study help developing high-resolution imaging of bio molecules.

    Read more

    Image from: DESY/Science Communication Lab

  • First experiments to develop single particle imaging

    SPI image of a nano-meter sized virus.An international collaboration has been formed by SLAC National Accelerator Laboratory to develop single particle imaging (SPI). Under the name of the SPI-initiative, we were awarded beam time at the AMO endstation and successfully performed single particle imaging with viruses. The picture you can see on the left is a diffraction pattern from a ~70nm in diameter virus. I had a leading role in running the AMO beam line and LAMP endstation, and was helping with sample injection during the beam time. There is a nicely written article on SLACs website if you would like to read on.

    Read More

  • Measuring transient states of matter using incoherent scattering

    Thomson Scattering MacDonald

    Measuring transient states of matter on the femto- to attosecond timescale is a current scientific challenge. Particularly for nanometer sized objects, the size of biomolecules for example proteins, it is a challenge to measure signal above the noise level due to low cross-sections. The amount of photons LCLS produces can overcome signal-to-noise issues and opens the door to perform measurements in entirely new regimes. In the featured and recently published study, we make use of LCLS in such a new way and measure an incoherent signal much above the noise level. The basis of this experiments is to spectrally resolve the scattering from free electrons or Thomson scattering. The developed method allows another way to gain insight into transient states, for example, the nanoplasma transformation or chemical reactions that last on the atto- to picosecond timescale. Particularly, parameters such as (electron) temperature, density and ionization levels can be measured using the LAMP endstation at LCLS. To make the proof-of-principle study, a pump-probe scheme was employed that first used an IR laser to induce a transient state (nanoplasma) in a nano-sample (argon clusters) and then secondly, after a time-delay, measures this state using the X-rays LCLS.

    Read more

  • Probing X-ray induced dynamics of molecules

    ncomms11652 f1I'm pleased to announce that my collaborator Antonio Picon has published his most recent results in Nature Communications. He uses an X-ray pump – X-ray probe concept to induce X-ray dynamics and subsequently probe them. It is one of the first experiments of its kind and uses the free electron laser at Stanford University to investigate ultrafast dynamics in molecules that happen on a femtosecond timescale. Experiments of this kind could be used in the future to better understand chemical reactions and to better understand how light interacts with matter. Particularly on ultrafast time scales.

    Read more

  • Shapes of rotating superfluid helium nanodroplets

    Classical stability versus quantum vorticiesPhys. Rev. B 95, 064510
    Charles Bernando, Rico Mayro P. Tanyag, Curtis Jones, Camila Bacellar, Maximilian Bucher, Ken R. Ferguson, Daniela Rupp, Michael Ziemkiewicz, Luis F. Gomez, Adam S. Chatterley, Tais Gorkhover, Maria Mueller, John Bozek, Sebastian Carron, Justin Kwok, Samuel L. Butler, Thomas Moeller, Christoph Bostedt, Oliver Gessner, and Andrey F. Vilesov
    Published 16 February 2017

  • The LAMP endstation at SLAC National Lab

    LAMP pnCCDsLAMP is a new endstation at the Linear Coherent Light Source (LCLS) that builds upon its predecessor CAMP. The LAMP endstation is versatile and is able to perform typical atomic, molecular & optical physics type experiments, but is also capable of imaging single particles, for example nanometer sized bio-molecules like viruses. I helped building the instrument and was part of the commissioning. The read-more button leads SLACs nicely written article about our endstation.

    Read more

  • Ultrafast X-ray Summer Seminar 2014

    At Stanford University, Menlo Park
    - Attendee

Social Media

Please find me also on social media pages.

 

Contact Me

+49(0)611 536-200
 

Kurhausplatz 1
D-65189 Wiesbaden
 

This email address is being protected from spambots. You need JavaScript enabled to view it.