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  • 1.
    Hertz, Hans
    et al.
    KTH.
    von Hofsten, Olov
    KTH.
    Bertilson, Mikael
    KTH.
    Vogt, Ulrich
    KTH.
    Holmberg, Anders
    KTH.
    Reinspach, Julia Antonia
    KTH.
    Martz, Dale
    KTH.
    Selin, Mårten
    KTH.
    Christakou, Athanasia
    KTH.
    Jerlström-Hultqvist, J
    Uppsala University.
    Svärd, S
    Uppsala University.
    Laboratory cryo soft X-ray microscopy2012In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 177, no 2, p. 267-272Article in journal (Refereed)
    Abstract [en]

    Lens-based water-window X-ray microscopy allows two- and three-dimensional (2D and 3D) imaging of intact unstained cells in their near-native state with unprecedented contrast and resolution. Cryofixation is essential to avoid radiation damage to the sample. Present cryo X-ray microscopes rely on synchrotron radiation sources, thereby limiting the accessibility for a wider community of biologists. In the present paper we demonstrate water-window cryo X-ray microscopy with a laboratory-source-based arrangement. The microscope relies on a lambda = 2.48-nm liquid-jet high-brightness laser-plasma source, normal-incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate 2D imaging of test patterns, and intact unstained yeast, protozoan parasites and mammalian cells. Overview 3D information is obtained by stereo imaging while complete 3D microscopy is provided by full tomographic reconstruction. The laboratory microscope image quality approaches that of the synchrotron microscopes, but with longer exposure times. The experimental image quality is analyzed from a numerical wave-propagation model of the imaging system and a path to reach synchrotron-like exposure times in laboratory microscopy is outlined.

  • 2.
    Martz, Dale H.
    et al.
    KTH.
    Selin, Mårten
    KTH.
    von Hofsten, Olov
    KTH.
    Fogelqvist, Emelie
    KTH.
    Holmberg, Anders
    KTH.
    Vogt, Ulrich
    KTH.
    Legall, H.
    Max-Born-Institute, Germany .
    Blobel, G.
    Max-Born-Institute, Germany .
    Seim, C.
    nstitute of Optics and Atomic Physics—Analytical X-ray physics, Germany .
    Stiel, H.
    Max-Born-Institute, Germany .
    Hertz, Hans M.
    KTH.
    High average brightness water window source for short-exposure cryomicroscopy2012In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, no 21, p. 4425-4427Article in journal (Refereed)
    Abstract [en]

    Laboratory water window cryomicroscopy has recently demonstrated similar image quality as synchrotron-based microscopy but still with much longer exposure times, prohibiting the spread to a wider scientific community. Here we demonstrate high-resolution laboratory water window imaging of cryofrozen cells with 10 s range exposure times. The major improvement is the operation of a lambda = 2.48 nm, 2 kHz liquid nitrogen jet laser plasma source with high spatial and temporal stability at high average brightness >1.5 x 10(12) ph/(s x sr x mu m(2) x line), i.e., close to that of early synchrotrons. Thus, this source enables not only biological x-ray microscopy in the home laboratory but potentially other applications previously only accessible at synchrotron facilities.

  • 3.
    Nilsson, Daniel
    et al.
    KTH.
    Uhlén, Fredrik
    KTH.
    Holmberg, Anders
    KTH.
    Hertz, Hans M.
    KTH.
    Schropp, Andreas
    SLAC National Accelerator Laboratory, Menlo Park, CA, USA & Institute of Structural Physics, Technische Universität Dresden, Germany.
    Patommel, Jens
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Hoppe, Robert
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Seiboth, Frank
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Meier, Vivienne
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Schroer, Christian G.
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Galtier, Eric
    Institute of Structural Physics, Technische Universität Dresden, Germany.
    Nagler, Bob
    SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
    Lee, Hae Ja
    SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
    Vogt, Ulrich
    KTH.
    Ronchi test for characterization of nanofocusing optics at a hard x-ray free-electron laser2012In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, no 24, p. 5046-5048Article in journal (Refereed)
    Abstract [en]

    We demonstrate the use of the classical Ronchi test to characterize aberrations in focusing optics at a hard x-ray free-electron laser. A grating is placed close to the focus and the interference between the different orders after the grating is observed in the far field. Any aberrations in the beam or the optics will distort the interference fringes. The methodis simple to implement and can provide single-shot information about the focusing quality. We used the Ronchi test to measure the aberrations in a nanofocusing Fresnel zone plate at the Linac Coherent Light Source at 8.194 keV.

  • 4.
    Nilsson, Daniel
    et al.
    KTH, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    KTH.
    Reinspach, Julia
    KTH.
    Hertz, Hans M.
    KTH.
    Holmberg, Anders
    KTH.
    Sinn, H.
    Vogt, Ulrich
    KTH.
    Thermal stability of tungsten zone plates for focusing hard x-ray free-electron laser radiation2012In: New Journal of Physics, ISSN 1367-2630, E-ISSN 1367-2630, Vol. 14, p. 043010-Article in journal (Refereed)
    Abstract [en]

    Diffractive Fresnel zone plates made of tungsten show great promise for focusing hard x-ray free-electron laser (XFEL) radiation to very small spot sizes. However, they have to withstand the high-intensity pulses of the beam without being damaged. This might be problematic since each XFEL pulse will create a significant temperature increase in the zone plate nanostructures and it is therefore crucial that the optics are thermally stable, even for a large number of pulses. Here we have studied the thermal stability of tungsten zone-platelike nanostructures on diamond substrates using a pulsed Nd:YAG laser which creates temperature profiles similar to those expected from XFEL pulses. We found that the structures remained intact up to a laser fluence of 100 mJ cm(-2), corresponding to a 6 keV x-ray fluence of 590 mJ cm-2, which is above typical fluence levels in an unfocused XFEL beam. We have also performed an initial damage experiment at the LCLS hard XFEL facility at SLAC National Accelerator Laboratory, where a tungsten zone plate on a diamond substrate was exposed to 105 pulses of 6 keV x-rays with a pulse fluence of 350 mJ cm-2 without any damage occurring.

  • 5.
    Selin, Mårten
    et al.
    KTH.
    Fogelqvist, Emelie
    KTH.
    Holmberg, Anders
    KTH.
    Guttmann, Peter
    Vogt, Ulrich
    KTH.
    Hertz, Hans M.
    KTH.
    3D simulation of the image formation in soft x-ray microscopes2014In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 22, no 25, p. 30756-30768Article in journal (Refereed)
    Abstract [en]

    In water-window soft x-ray microscopy the studied object is typically larger than the depth of focus and the sample illumination is often partially coherent. This blurs out-of-focus features and may introduce considerable fringing. Understanding the influence of these phenomena on the image formation is therefore important when interpreting experimental data. Here we present a wave-propagation model operating in 3D for simulating the image formation of thick objects in partially coherent soft x-ray microscopes. The model is compared with present simulation methods as well as with experiments. The results show that our model predicts the image formation of transmission soft x-ray microscopes more accurately than previous models.

  • 6.
    Uhlén, Fredrik
    et al.
    KTH.
    Nilsson, Daniel
    KTH.
    Holmberg, Anders
    KTH.
    Hertz, Hans M.
    KTH.
    Schroer, C. G.
    Seiboth, F.
    Patommel, J.
    Meier, V.
    Hoppe, R.
    Schropp, A.
    Lee, H. J.
    Nagler, B.
    Galtier, E.
    Krzywinski, J.
    Sinn, H.
    Vogt, Ulrich
    KTH.
    Damage investigation on tungsten and diamond diffractive optics at a hard x-ray free-electron laser2013In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 21, no 7, p. 8051-8061Article in journal (Refereed)
    Abstract [en]

    Focusing hard x-ray free-electron laser radiation with extremely high fluence sets stringent demands on the x-ray optics. Any material placed in an intense x-ray beam is at risk of being damaged. Therefore, it is crucial to find the damage thresholds for focusing optics. In this paper we report experimental results of exposing tungsten and diamond diffractive optics to a prefocused 8.2 keV free-electron laser beam in order to find damage threshold fluence levels. Tungsten nanostructures were damaged at fluence levels above 500 mJ/cm(2). The damage was of mechanical character, caused by thermal stress variations. Diamond nanostructures were affected at a fluence of 59 000 mJ/cm(2). For fluence levels above this, a significant graphitization process was initiated. Scanning Electron Microscopy (SEM) and mu-Raman analysis were used to analyze exposed nanostructures.

  • 7.
    Uhlén, Fredrik
    et al.
    KTH.
    Nilsson, Daniel
    KTH.
    Rahomäki, Jussi
    KTH.
    Belova, Liubov
    KTH.
    Schroer, Christian G.
    Seiboth, Frank
    Holmberg, Anders
    KTH.
    Hertz, Hans M.
    KTH.
    Vogt, Ulrich
    KTH.
    Nanofabrication of tungsten zone plates with integrated platinum central stop for hard X-ray applications2014In: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 116, p. 40-43Article in journal (Refereed)
    Abstract [en]

    We present a nanofabrication process for producing tungsten zone plates used in hard X-ray applications including a method of integrating a high-energy absorbing central stop with the optic. Tungsten zone plates are structured with electron-beam lithography and subsequent reactive ion etching. The central stop originates from a platinum wire. It is cut to dimension by focused ion beam etching, and afterwards attached to the zone plate center using ion beam induced deposition of platinum. A zone plate with integrated central stop will simplify alignment in hard X-ray scanning microscope arrangements where the 0th order light must be eliminated. The focusing performance of the zone plate device was investigated by scanning coherent diffraction imaging (ptychography) at 8 keV photon energy. We could demonstrate a diffraction-limited focus size of 53 nm diameter full-width-at-half-maximum. Tungsten zone plates with integrated central stops show promising results for use in hard X-ray microscopes at high-brightness facilities.

  • 8.
    Vogt, Ulrich
    et al.
    KTH.
    Reinspach, Julia
    KTH.
    Uhlén, Fredrik
    KTH.
    Nilsson, Daniel
    KTH.
    Hertz, Hans M.
    KTH.
    Holmberg, Anders
    KTH.
    Diffractive optics for laboratory sources to free electron lasers2013In: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics (IOP), 2013, p. 012001-Conference paper (Refereed)
    Abstract [en]

    In this contribution we present our recent results in the field of diffractive optics for both soft and hard x-ray radiation, and for laboratory sources to x-ray free electron lasers (XFEL). We developed a laboratory soft x-ray microscope that uses in-house produced zone plate optics as high-resolution objectives. We continuously try to improve these optics, both in terms of efficiency and resolution. Our latest development is the manufacturing of tungsten soft x-ray zone plates with outermost zone widths of 12 nm and 90 nm high structures. For hard x-rays, we investigated the possibility to use metal zone plates on a diamond substrate for nano-focusing of the European X-ray Free Electron Laser. The simulations show that the heat conduction is efficient enough to keep a zone plate well below melting temperature. However, metal zone plates will experience large and rapid temperature fluctuations of several hundred Kelvin that might prove fatal. To test this, we manufactured tungsten on diamond prototype zone plates and exposed them to radiation from the LCLS XFEL. Results show that metal zone plates can survive the XFEL beam.

1 - 8 of 8
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