| 1. |
- Burza, Matthias, et al.
(author)
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Dispersion and monochromatization of x-rays using a beryllium prism
- 2015
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In: Optics Express. - 1094-4087. ; 23:2, s. 620-627
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Journal article (peer-reviewed)abstract
- We demonstrate experimentally and numerically that an x-ray prism made of beryllium can be used to disperse and monochromatize x-rays. A polished beryllium cuboid was employed as refractive and dispersive optics. The results of a proof-of-principle experiment and methods of performance optimization are presented. The spatial separation of undulator harmonics and their subsequent selection using a slit are described. A numerical study, assuming realistic beam and beamline parameters, suggests that undulator harmonics can be spatially separated in the range from 3 keV to beyond 20 keV, while maintaining throughput above 50%. Refractive optics is particularly suitable for low-repetition-rate sources such as free-electron lasers and other LINAC-based short-pulse sources. (C) 2015 Optical Society of America
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| 2. |
- Enquist, Henrik, et al.
(author)
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FemtoMAX - An X-ray beamline for structural dynamics at the short-pulse facility of MAX IV
- 2018
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In: Journal of Synchrotron Radiation. - 0909-0495. ; 25:2, s. 570-579
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Journal article (peer-reviewed)abstract
- The FemtoMAX beamline facilitates studies of the structural dynamics of materials. Such studies are of fundamental importance for key scientific problems related to programming materials using light, enabling new storage media and new manufacturing techniques, obtaining sustainable energy by mimicking photosynthesis, and gleaning insights into chemical and biological functional dynamics. The FemtoMAX beamline utilizes the MAX IV linear accelerator as an electron source. The photon bursts have a pulse length of 100fs, which is on the timescale of molecular vibrations, and have wavelengths matching interatomic distances (Å). The uniqueness of the beamline has called for special beamline components. This paper presents the beamline design including ultrasensitive X-ray beam-position monitors based on thin Ce:YAG screens, efficient harmonic separators and novel timing tools.The FemtoMAX beamline facilitates studies of the structural dynamics of materials on the femtosecond timescale. The first commissioning results are presented.
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| 3. |
- Wahlström, Claes-Göran, et al.
(author)
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Supersonic jets of hydrogen and helium for laser wakefield acceleration
- 2016
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In: Physical Review Accelerators and Beams. - 2469-9888. ; 19
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Journal article (peer-reviewed)abstract
- The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ∼30% higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.
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