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  • 51.
    Vogt, Ulrich
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Uhlén, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Nilsson, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Diffractive optics for laboratory sources to free electron lasers2013Inngår i: 11th International Conference On X-Ray Microscopy (XRM2012), Institute of Physics (IOP), 2013, Vol. 463, nr 1, s. 012001-Konferansepaper (Fagfellevurdert)
    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.

  • 52.
    von Hofsten, Olof
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, M.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Compact Zernike phase contrast x-ray microscopy using a single-element optic2008Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 33, nr 9, s. 932-934Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We demonstrate Zernike phase contrast in a compact soft x-ray microscope using a single-element optic. The optic is a combined imaging zone plate and a Zernike phase plate and does not require any additional alignment or components. Contrast is increased and inversed in an image of a test object using the Zernike zone plate. This type of optic may be implemented into any existing x-ray microscope where phase contrast is of interest.

  • 53.
    von Hofsten, Olof
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Reinspach, Julia
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik.
    Sub-25-nm laboratory x-ray microscopy using a compound Fresnel zone plate2009Inngår i: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 34, nr 17, s. 2631-2633Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Improving the resolution in x-ray microscopes is of high priority to enable future applications in nanoscience. However, high-resolution zone-plate optics often have low efficiency, which makes implementation in laboratory microscopes difficult. We present a laboratory x-ray microscope based on a compound zone plate. The compound zone plate utilizes multiple diffraction orders to achieve high resolution while maintaining reasonable efficiency. We analyze the illumination conditions necessary for this type of optics in order to suppress stray light and demonstrate microscopic imaging resolving 25 nm features.

  • 54.
    von Hofsten, Olov
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Bertilson, Michael
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Lindblom, Magnus
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Hertz, Hans M.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Vogt, Ulrich
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Compact phase-contrast soft X-ray microscopy2009Inngår i: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 186Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For nearly all elements, the real part, delta, of the complex index of refraction n (n = 1 - delta + i beta) is larger than the imaginary part, beta, in the x-ray region. Since only beta is used in absorption contrast, phase-contrast imaging techniques which give access to delta are very important. In this paper we present two different implementations of phase contrast in our compact soft x-ray microscope, differential-interference contrast and Zemike phase contrast.

  • 55. Welch, C. C.
    et al.
    Olynick, D. L.
    Liu, Z.
    Holmberg, Anders
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Peroz, C.
    Robinson, A. P. G.
    Henry, M. D.
    Scherer, A.
    Mollenhauer, T.
    Genova, V.
    Ng, D. K. T.
    Formation of nanoscale structures by inductively coupled plasma etching2012Inngår i: International Conference Micro- and Nano-Electronics 2012, SPIE - International Society for Optical Engineering, 2012, s. 870002-Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper will review the top down technique of ICP etching for the formation of nanometer scale structures. The increased difficulties of nanoscale etching will be described. However it will be shown and discussed that inductively coupled plasma (ICP) technology is well able to cope with the higher end of the nanoscale: features from 100nm down to about 40nm are relatively easy with current ICP technology. It is the ability of ICP to operate at low pressure yet with high plasma density and low (controllable) DC bias that helps greatly compared to simple reactive ion etching (RIE) and, though continual feature size reduction is increasingly challenging, improvements to ICP technology as well as improvements in masking are enabling sub-10nm features to be reached. Nanoscale ICP etching results will be illustrated in a range of materials and technologies. Techniques to facilitate etching (such as the use of cryogenic temperatures) and techniques to improve the mask performance will be described and illustrated.

  • 56.
    Wirta, Valtteri
    et al.
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Holmberg, Anders
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Lukacs, Morten
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Nilsson, Peter
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Hilson, Pierre
    Uhlén, Mathias
    Bhalerao, Rishikesh
    Lundeberg, Joakim
    KTH, Skolan för bioteknologi (BIO), Molekylär Bioteknologi.
    Assembly of a gene sequence tag microarray by reversible biotin-streptavidin capture for transcript analysis of Arabidopsis thaliana2005Inngår i: BMC Biotechnology, ISSN 1472-6750, E-ISSN 1472-6750, Vol. 5, s. 5-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Background: Transcriptional profiling using microarrays has developed into a key molecular tool for the elucidation of gene function and gene regulation. Microarray platforms based on either oligonucleotides or purified amplification products have been utilised in parallel to produce large amounts of data. Irrespective of platform examined, the availability of genome sequence or a large number of representative expressed sequence tags ( ESTs) is, however, a pre-requisite for the design and selection of specific and high-quality microarray probes. This is of great importance for organisms, such as Arabidopsis thaliana, with a high number of duplicated genes, as cross-hybridisation signals between evolutionary related genes cannot be distinguished from true signals unless the probes are carefully designed to be specific.

    Results: We present an alternative solid-phase purification strategy suitable for efficient preparation of short, biotinylated and highly specific probes suitable for large-scale expression profiling. Twenty-one thousand Arabidopsis thaliana gene sequence tags were amplified and subsequently purified using the described technology. The use of the arrays is exemplified by analysis of gene expression changes caused by a four-hour indole-3-acetic ( auxin) treatment. A total of 270 genes were identified as differentially expressed ( 120 up-regulated and 150 down-regulated), including several previously known auxin-affected genes, but also several previously uncharacterised genes.

    Conclusions: The described solid-phase procedure can be used to prepare gene sequence tag microarrays based on short and specific amplified probes, facilitating the analysis of more than 21 000 Arabidopsis transcripts.

12 51 - 56 of 56
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