| 1. |
- Legall, H., et al.
(författare)
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A compact laboratory transmission X-ray microscope for the water window
- 2013
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 463:1, s. 012013-
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Tidskriftsartikel (refereegranskat)abstract
- In the water window (2.2-4.4 nm) the attenuation of radiation in water is significantly smaller than in organic material. Therefore, intact biological specimen (e.g. cells) can be investigated in their natural environment. In order to make this technique accessible to users in a laboratory environment a Full-Field Laboratory Transmission X-ray Microscope (L-TXM) has been developed. The L-TXM is operated with a nitrogen laser plasma source employing an InnoSlab high power laser system for plasma generation. For microscopy the Ly α emission of highly ionized nitrogen at 2.48 nm is used. A laser plasma brightness of 5 × 1011 photons/(s × sr × μm2 in line at 2.48 nm) at a laser power of 70 W is demonstrated. In combination with a state-of-the-art Cr/V multilayer condenser mirror the sample is illuminated with 106 photons/(μm2 × s). Using objective zone plates 35-40 nm lines can be resolved with exposure times < 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W. These exposure times enable cryo tomography in a laboratory environment.
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| 2. |
- Legall, H., et al.
(författare)
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Compact X-ray microscope for the water window based on a high brightness laser plasma source
- 2012
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Ingår i: Optics Express. - 1094-4087. ; 20:16, s. 18362-18369
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Tidskriftsartikel (refereegranskat)abstract
- We present a laser plasma based x-ray microscope for the water window employing a high-average power laser system for plasma generation. At 90 W laser power a brightness of 7.4 x 10(11) photons/(s x sr x mu m(2)) was measured for the nitrogen Ly alpha line emission at 2.478 nm. Using a multilayer condenser mirror with 0.3 % reflectivity 10(6) photons/(mu m(2) x s) were obtained in the object plane. Microscopy performed at a laser power of 60 W resolves 40 nm lines with an exposure time of 60 s. The exposure time can be further reduced to 20 s by the use of new multilayer condenser optics and operating the laser at its full power of 130 W.
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| 3. |
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| 4. |
- halide, halmar, et al.
(författare)
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Developing a decision support system for sustainable cage aquaculture
- 2009
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Ingår i: Environmental Modelling and Software. - : Elsevier BV. - 1364-8152. ; 24:6, s. 694-702
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Tidskriftsartikel (refereegranskat)abstract
- A decision support system to assist cage aquaculture managers is presented. The system enables managers to perform four essential tasks: (i) site classification, (ii) site selection, (iii) holding capacity determination, and (iv) economic appraisal of an aquaculture farm at a given site. Based on measurements of water and substrate qualities, hydrometeorology and socioeconomic factors, a cage aquaculture site is classified into three categories – poor, medium, and good. With this information, the AHP (analytical hierarchy process) tool is used to evaluate the best site from several alternatives. A simplified version of the Modelling-On growing-Monitoring (MOM), SMOM, is developed and applied to determine how much fish can be grown on site without harming the environment. The simplified model has been calibrated against MOM, compared with other carrying capacity models and validated with farm data. A break-even point–price and return on investment (ROI) are calculated using cage-holding density and volume, mean fish weight at harvest, feed conversion ratio (FCR), survival rate of seed, costs of feed, seed and cages, the interest rate on borrowed funds and the fish price. All model components are integrated seamlessly into a user-friendly interface implemented in Java® called CADS_TOOL (Cage Aquaculture Decision Support Tool). The program with a user's guide is freely available.
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| 5. |
- Hertz, Hans M., et al.
(författare)
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Table-top X-ray microscopy : Sources, optics and applications
- 2003
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Ingår i: Journal de Physique IV. - : EDP Sciences. - 1155-4339 .- 1764-7177. ; 104, s. 115-119
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Tidskriftsartikel (refereegranskat)abstract
- We have developed the first operative compact sub-visible-resolution x-ray microscope for the water-window region (lambda = 2.3 - 4.4 nm). The microscope is based on a 100 Hz liquid-jet-target laser-plasma x-ray source, normal-incidence multilayer condenser optics, diffractive zone plate optics and CCD detection. In the present article we emphasize the system's aspects and summarize the recent progress on the components, all aiming at the reduction of the exposure time of a few seconds, i.e., similar to bending-magnet based microscopes. This primarily includes improved laser-plasma source, improved condenser optics using Cr/Sc multilayers, and improved image handling capability using wavelet algorithms. Such compact short-exposure time microscopes would significantly increase the applicability of the technology.
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| 6. |
- Holmberg, Anders, et al.
(författare)
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Nano-fabrication of condenser and micro zone plates for compact X-ray microscopy
- 2004
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 73/74, s. 639-643
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate nano-fabrication of high-aspect ratio and high-spatial frequency diffractive X-ray optics with high uniformity for use in a laser-plasma-based compact water-window X-ray microscope. The structures are fabricated on 50 nm thin Si3N4-membranes using a three-layer resist scheme and 30 keV e-beam lithography in combination with reactive ion etching and nickel electroplating. The process is developed on solely commercially available resists and instruments. As examples, we demonstrate fabrication of micro-zone plates with outermost linewidths of 30 nm and an uniform zone height of 160 nm, and a 4.5 mm diameter condenser zone plate with 50-60 nm lines, fabricated by using stitched fields.
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