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Laboratory Soft X-Ray Cryo Tomography
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
Visa övriga samt affilieringar
(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

X-rays allow quantitative high-spatial-resolution three-dimensional (3D) imaging of intact unstained cells. Such 3D imaging is provided by soft x-ray lens-based methods (water-window cryo tomography) and hard x-ray lens-less methods (coherent diffraction imaging) are emerging. However, both methods rely on high-brightness synchrotron-radiation sources, which limit the accessibility of a wider scientific community. Here we show 3D water-window cryo tomography with a laboratory-source-based microscope arrangement. The system relies on a λ=2.48-nm liquid-jet laser-plasma source, normal- incidence multilayer condenser optics, 30-nm zone-plate optics, and a cryo sample chamber. We demonstrate imaging of intact unstained yeast, protozoan parasites and mammalian cells. 3D images show noise-limited features close to ~100 nm and intra-cellular structure is classified based on the local absorption coefficient. A comprehensive theoretical model of the tomographic imaging system allows optimization of system parameters and a quantitative estimate of the 3D imaging accuracy. The model includes issues such as non-geometric projections of the thick samples and stray light, and is applicable to laboratory as well as synchrotron-based x-ray microscopes. The model shows that laboratory x-ray cryo tomography will allow quantitative 3D imaging with ~30-nm (half-period) resolution over a full 5 µm object.

 

Nationell ämneskategori
Fysik
Identifikatorer
URN: urn:nbn:se:kth:diva-29938OAI: oai:DiVA.org:kth-29938DiVA, id: diva2:398428
Anmärkning
QC 20110217Tillgänglig från: 2011-02-17 Skapad: 2011-02-17 Senast uppdaterad: 2011-02-21Bibliografiskt granskad
Ingår i avhandling
1. Laboratory soft x-ray microscopy and tomography
Öppna denna publikation i ny flik eller fönster >>Laboratory soft x-ray microscopy and tomography
2011 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Soft x-ray microscopy in the water-window (λ = 2.28 nm – 4.36 nm) is based on zone-plate optics and allows high-resolution imaging of, e.g., cells and soils in their natural or near-natural environment. Three-dimensional imaging is provided via tomographic techniques, soft x-ray cryo tomography. However, soft x-ray microscopes with such capabilities have been based on large-scale synchrotron x‑ray facilities, thereby limiting their accessibility for a wider scientific community.

This Thesis describes the development of the Stockholm laboratory soft x-ray microscope to three-dimensional cryo tomography and to new optics-based contrast mechanisms. The microscope relies on a methanol or nitrogen liquid-jet laser-plasma source, normal-incidence multilayer or zone-plate condenser optics, in-house fabricated zone-plate objectives, and allows operation at two wavelengths in the water-window, λ = 2.48 nm and λ = 2.48 nm. With the implementation of a new state-of-the-art normal-incidence multilayer condenser for operation at λ = 2.48 nm and a tiltable cryogenic sample stage the microscope now allows imaging of dry, wet or cryo-fixed samples. This arrangement was used for the first demonstration of laboratory soft x-ray cryo microscopy and tomography. The performance of the microscope has been demonstrated in a number of experiments described in this Thesis, including, tomographic imaging with a resolution of 140 nm, cryo microscopy and tomography of various cells and parasites, and for studies of aqueous soils and clays. The Thesis also describes the development and implementation of single-element differential-interference and Zernike phase-contrast zone-plate objectives. The enhanced contrast provided by these optics reduce exposure times or lowers the dose in samples and are of major importance for harder x-ray microscopy. The implementation of a high-resolution 50 nm compound zone-plate objective for sub-25-nm resolution imaging is also described. All experiments are supported by extensive numerical modelling for improved understanding of partially coherent image formation and stray light in soft x-ray microscopes. The models are useful tools for studying effects of zone plate optics or optical design of the microscope on image formation and quantitative accuracy in soft x-ray tomography.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2011. s. x, 76
Serie
Trita-FYS, ISSN 0280-316X ; 2011:03
Nyckelord
Microscopy, X-ray optics, Diffractive optics, Zone plates, X-ray microscopy, Soft X-ray physics, Tomography
Nationell ämneskategori
Atom- och molekylfysik och optik Fysik
Identifikatorer
urn:nbn:se:kth:diva-29950 (URN)978-91-7415-874-8 (ISBN)
Disputation
2011-02-25, FB42, AlbaNova Universitetscentrum, Roslagstullsbacken 21, Stockholm, 13:00 (Engelska)
Opponent
Handledare
Anmärkning
QC 20110221Tillgänglig från: 2011-02-21 Skapad: 2011-02-18 Senast uppdaterad: 2011-02-21Bibliografiskt granskad

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Hertz, Hans M.

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Av författaren/redaktören
Bertilson, Michaelvon Hofsten, OlovHolmberg, AndersChristakou, AthanasiaHertz, Hans M.
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Biomedicinsk fysik och röntgenfysik
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