| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Bertilson, Michael C., et al.
(författare)
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Zone plate efficiency measurements with a laser-plasma source
- 2007
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Ingår i: Advances in X-Ray/EUV Optics and Components II. - : SPIE. - 9780819468536 ; , s. F7050-F7050
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a compact instrument for rapid and accurate measurements of the absolute and local efficiency of soft x-ray zone plates in the water window [M. Bertilson, et al, Rev. Sci. Instrum 78, 026103 (2007)]. The arrangement is based on a new single-line lambda = 2.88 nm liquid-nitrogen-jet laser-plasma source. The versatility of the instrument enables micro and condenser zone plates with focal lengths in the range from similar to 200 mu m to similar to 100 mm to be measured. We demonstrate an accurate local efficiency map of a in-house fabricated micro zone plate. Furthermore, we show how this compact instrument allows rapid feedback to the fabrication process which is important for future improvements.
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| 3. |
- Bertilson, Michael, et al.
(författare)
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First application experiments with the Stockholm compact soft x-ray microscope
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- Most soft x-ray microscopes operating in the water window (lambda = 2.3 - 4.4 nm) rely on synchrotron radiation sources. In the future we believe scientists will use soft x-ray microscopes as one imaging tool among others in their own laboratory. For this purpose we have developed a full field soft x-ray microscope with a laser-plasma source compact enough to fit on an optical table. In this contribution we describe the current status of this microscope now featuring stable operation at lambda = 3.37 nm or lambda = 2.48 nm. In-house fabricated single element zone plates offering the possibility to perform phase contrast imaging have been implemented. We also report on the first application experiments for compact soft x-ray microscopy, including results from studies of clay minerals and colloids existing in nature and results from phase optics experiments. Planned upgrades of the microscope include increasing the source brightness, implementing more efficient condenser optics, and installing a cryo sample stage for tomography. These improvements will open up for further applications, especially in the field of biological imaging.
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| 4. |
- Bertilsson, Michael, et al.
(författare)
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Laboratory arrangement for soft x-ray zone-plate efficiency measurements
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:2, s. 026103-
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a laboratory-scale arrangement for rapid and accurate measurements of the absolute and local efficiency of soft x-ray micro zone plates in the water window. This in-house instrument is based on a single-line lambda=2.88 nm liquid-jet laser-plasma source. Measurements are performed by a simultaneous comparison of first diffraction-order photon flux with the flux in a calibrated reference signal. This arrangement eliminates existing source emission fluctuations. The performance of the method is demonstrated by the result from measurements of two similar to 55 mu m diameter nickel micro zone plates, showing a groove efficiency of 12.9%+/- 1.1% and 11.7%+/- 1.0%. Furthermore, we show that spatially resolved efficiency mapping is an effective tool for a detailed characterization of local zone plate properties. Thus, this laboratory-scale instrument allows rapid feedback to the fabrication process which is important for future improvements.
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| 5. |
- Burvall, Anna, et al.
(författare)
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Phase retrieval in X-ray phase-contrast imaging suitable for tomography
- 2011
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Ingår i: Optics Express. - 1094-4087. ; 19:11, s. 10359-10376
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Tidskriftsartikel (refereegranskat)abstract
- In-line phase-contrast X-ray imaging provides images where both absorption and refraction contribute. For quantitative analysis of these images, the phase needs to be retrieved numerically. There are many phase-retrieval methods available. Those suitable for phase-contrast tomography, i.e., non-iterative phase-retrieval methods that use only one image at each projection angle, all follow the same pattern though derived in different ways. We outline this pattern and use it to compare the methods to each other, considering only phase-retrieval performance and not the additional effects of tomographic reconstruction. We also outline derivations, approximations and assumptions, and show which methods are similar or identical and how they relate to each other. A simple scheme for choosing reconstruction method is presented, and numerical phase-retrieval performed for all methods.
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| 6. |
- Burvall, Anna, et al.
(författare)
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X-ray in-line phase retrieval for tomography
- 2012
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Ingår i: Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE - International Society for Optical Engineering. - 9780819489623 ; , s. 83136A-
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Konferensbidrag (refereegranskat)abstract
- Phase contrast in X-ray imaging offers imaging of fine features at lower doses than absorption. Of the phasecontrast methods in use in-line phase contrast is interesting due to its experimental simplicity, but to extract information on absorption and phase distributions from the resulting images, phase retrieval is needed. Many phase-retrieval methods suitable for different situations have been developed, but few comparisons of those methods done. We consider a sub-group of phase-retrieval methods that are suitable for tomography, i.e., that use only one exposure (for practical experimental reasons) and are non-iterative (for speed). In total we have found seven suitable methods in the literature. All, though derived in different ways under different assumptions, follow the same pattern and can be outlined as a single method where each specific version is marked by variations in particular steps. We summarize this unified approach, and give the variations of the individual methods. In addition, we outline approximations and assumptions of each method. Using this approach it is possible to conclude which specific algorithms are most suitable in specific situations and to test this based on simulated and experimental data. Ultimately, this leads to conclusions on which methods are the most suitable in different situations.
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| 7. |
- Hertz, Hans M., et al.
(författare)
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Laboratory X-ray micro- and nano-imaging
- 2009
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Ingår i: Frontiers in Optics (FiO) 2009. - Washington, D.C. : Optical Society of America. - 9781557528780
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Konferensbidrag (refereegranskat)abstract
- We summarize recent progress in laboratory x-ray imaging systems based on compact high-brightness liquid-jet sources, including <25 nm soft x-ray zone-plate microscopy and <10 μm (lens-free) hard x-ray phase-contrast imaging.
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| 8. |
- Hertz, Hans M., et al.
(författare)
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Laboratory x-ray micro imaging : Sources, optics, systems and applications
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- We summarize the recent progress in laboratory-scale soft and hard x-ray micro imaging in Stockholm. Our soft x-ray work is based on liquid-jet laser-plasma sources which are combined with diffractive and multilayer optics to form laboratory x-ray microscopes. In the hard x-ray regime the imaging is based on a liquid-metal-jet electron-impact source which provides the necessary coherence to allow phase-contrast imaging with high fidelity.
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| 9. |
- Holmberg, Anders, et al.
(författare)
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Towards 10-nm Soft X-Ray Zone Plate Fabrication
- 2011
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Konferensbidrag (refereegranskat)abstract
- In this paper the latest efforts to improve our nanofabrication process for soft x‐ray zone plates is presented. The resolving power, which is proportional to the smallest outermost zone width of the zone plate, is increased by introducing cold development of the electron beam resist that is used for the patterning. With this process we have fabricated Ni zone plates with 13‐nm outermost zone and shown potential for making 11‐nm half‐pitch lines in the electron beam resist. Maintaining the diffraction efficiency of the zone plate is a great concern when the outermost zone width is decreased. To resolve this problem we have developed the so‐called Ni‐Ge zone plate in which the zone plate is build up by Ni and Ge, resulting in an increase of the diffraction efficiency. In a proof‐of‐principle experiment with 25‐nm Ni‐Ge zone plates, we have shown a doubling of the diffraction efficiency. When combined with cold development, the Ni‐Ge process has been shown to work down to 16‐nm half‐pitch. It is plausible that further refinement of the process will make it possible to go to 10‐nm outermost zone widths.
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| 10. |
- Holmgren, Kristina, 1977-, et al.
(författare)
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KNOGA. Fossilfri framdrift för tunga långväga godstransporter på väg : kostnadsfördelning och risker för olika aktörer (Executive summary)
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Användningen av förnybar energi i transportsektorn behöver öka för att vi ska nå de svenska klimatmålen om minskade växthusgasutsläpp från inrikes transporterna med 70 procent till 2030, och nettonollutsläpp från samtliga sektorer till 2045. Ökningen av förnybara drivmedel behöver ske i alla segment och över hela fordonsflottan.Idag används främst diesel som drivmedel för tunga långväga godstransporter på väg men det finns alternativ för fossilfri framdrift. Denna studie har kvantifierat kostnadsstrukturer och analyserat riskfördelning mellan olika aktörer för fossilfria framdriftstekniker för tunga långväga godstransporter på väg och jämfört dem med alternativet att fortsätta använda diesel som drivmedel. Följande tekniker är inkluderade i studien: biobränslen (flytande och gasformiga), batterielektriska fordon (BEV), elvägar (tre olika tekniker), vätgasdrivna bränslecellsfordon (H2-FCEV) samt elektrobränslen. Beräkningar görs för år 2030 och 2045. Från de fem huvudkategorierna för fossilfri framdrift har ett antal representativa motortekniker, bränsleproduktionstekniker och råvaror valts ut för att analyseras i detalj. Detta har resulterat i ett trettiotal olika fossilfria alternativ till dagens användning av fossil diesel
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