| 1. |
- Moberg, Christina, et al.
(författare)
-
De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
|
|
| 2. |
- Bertilson, Michael C., et al.
(författare)
-
Zone plate efficiency measurements with a laser-plasma source
- 2007
-
Ingår i: Advances in X-Ray/EUV Optics and Components II. - : SPIE. - 9780819468536 ; , s. F7050-F7050
-
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.
|
|
| 3. |
|
|
| 4. |
- Burvall, Anna, et al.
(författare)
-
Phase retrieval in X-ray phase-contrast imaging suitable for tomography
- 2011
-
Ingår i: Optics Express. - 1094-4087. ; 19:11, s. 10359-10376
-
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.
|
|
| 5. |
- Larsson, Daniel H., et al.
(författare)
-
A 24 keV liquid-metal-jet x-ray source for biomedical applications
- 2011
-
Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 82:12, s. 123701-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a high-brightness 24-keV electron-impact microfocus x-ray source based on continuous operation of a heated liquid-indium/gallium-jet anode. The 30–70 W electron beam is magnetically focused onto the jet, producing a circular 7–13 μm full width half maximum x-ray spot. The measured spectral brightness at the 24.2 keV In Kα line is 3 × 109 photons/(s × mm2 × mrad2 × 0.1% BW) at 30 W electron-beam power. The high photon energy compared to existing liquid-metal-jet sources increases the penetration depth and allows imaging of thicker samples. The applicability of the source in the biomedical field is demonstrated by high-resolution imaging of a mammography phantom and a phase-contrast angiography phantom.
|
|
| 6. |
- Lundström, Ulf, et al.
(författare)
-
X-ray phase contrast for CO2 microangiography
- 2012
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 57:9, s. 2603-2617
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a laboratory method for imaging small blood vessels using x-ray propagation-based phase-contrast imaging and carbon dioxide (CO2) gas as a contrast agent. The limited radiation dose in combination with CO2 being clinically acceptable makes the method promising for small-diameter vascular visualization. We investigate the possibilities and limitations of the method for small-animal angiography and compare it with conventional absorption-based x-ray angiography. Photon noise in absorption-contrast imaging prevents visualization of blood vessels narrower than 50 mu m at the highest radiation doses compatible with living animals, whereas our simulations and experiments indicate the possibility of visualizing 20 mu m vessels at radiation doses as low as 100 mGy. Experimental computed tomography of excised rat kidney shows blood vessels of diameters down to 60 mu m with improved image quality compared to absorption-based methods. With our present prototype x-ray source, the acquisition time for a tomographic dataset is approximately 1 h, which is long compared to the 1-20 min common for absorption-contrast micro-CT systems. Further development of the liquid-metal-jet microfocus x-ray sources used here and high-resolution x-ray detectors shows promise to reduce exposure times and make this high-resolution method practical for imaging of living animals.
|
|
