Showing papers by "Stuart Mangles published in 2011"
TL;DR: Kneip et al. as discussed by the authors used a high power short pulse laser in a tenuous gas jet, setting up a plasma wakefield accelerator that accelerates and wiggles electrons analogously to a conventional synchrotron, but on the centimeter rather than tens of meter scale.
Abstract: We show that x-rays from a recently demonstrated table top source of bright, ultrafast, coherent synchrotron radiation [Kneip et al., Nat. Phys. 6, 980 (2010)] can be applied to phase contrast imaging of biological specimens. Our scheme is based on focusing a high power short pulse laser in a tenuous gas jet, setting up a plasma wakefield accelerator that accelerates and wiggles electrons analogously to a conventional synchrotron, but on the centimeter rather than tens of meter scale. We use the scheme to record absorption and phase contrast images of a tetra fish, damselfly and yellow jacket, in particular highlighting the contrast enhancement achievable with the simple propagation technique of phase contrast imaging. Coherence and ultrafast pulse duration will allow for the study of various aspects of biomechanics.
125 citations
TL;DR: In this article, it was shown that the capillary collects energy outside the main peak of the focal spot and contributes to keep the beam self-focused over a distance longer than in a gas jet of similar density.
Abstract: Electron beams and betatron X-ray radiation generated by laser wakefield acceleration in long plasma targets are studied. The targets consist of hydrogen filled dielectric capillary tubes of diameter 150 to 200 microns and length 6 to 20 mm. Electron beams are observed for peak laser intensities as low as 5×1017 W/cm2. It is found that the capillary collects energy outside the main peak of the focal spot and contributes to keep the beam self-focused over a distance longer than in a gas jet of similar density. This enables the pulse to evolve enough to reach the threshold for wavebreaking, and thus trap and accelerate electrons. No electrons were observed for capillaries of large diameter (250 μm), confirming that the capillary influences the interaction and does not have the same behaviour as a gas cell. Finally, X-rays are used as a diagnostic of the interaction and, in particular, to estimate the position of the electrons trapping point inside the capillary.
29 citations
TL;DR: In this article, a self-injecting laser wakefield accelerator driven at a plasma density of 5.5 × 1018 cm−3 was used to accelerate up to 0.8 GeV in the blowout regime.
Abstract: Electrons are accelerated up to 0.8 GeV in a self-injecting laser wakefield accelerator driven at a plasma density of 5.5 × 1018 cm−3 by a 10 J, 55 fs, 800 nm laser pulse in the blow-out regime. The electron beam stability is correlated with the laser focal spot pointing stability and depends on the target alignment. Variations of the laser pulse energy, focal spot size and energy within the full width at half maximum have little effect on the electron beam profile (stability) but impact the electron energy (stability). The peak electron energy is higher than expected for the initial vacuum intensity. This is evidence for intensity amplification which also explains the observation of polyenergetic beamlets.
9 citations
TL;DR: In this article, the x-rays from a tabletop source of bright coherent synchrotron radiation are applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
Abstract: Since their discovery in 1896, x-rays have had a profound impact on science, medicine and technology. Here we show that the x-rays from a novel tabletop source of bright coherent synchrotron radiation can be applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
2 citations
TL;DR: In this paper, the x-rays from a tabletop source of bright coherent synchrotron radiation are applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
Abstract: Since their discovery in 1896, x-rays have had a profound impact on science, medicine and technology. Here we show that the x-rays from a novel tabletop source of bright coherent synchrotron radiation can be applied to phase contrast imaging of biological specimens, yielding superior image quality and avoiding the need for scarce or expensive conventional sources.
1 citations
TL;DR: In this paper, the first well-resolved experimental observation of the non-linear formation of a laser-driven plasma wave, its breaking leading to self-injection and acceleration of electrons in the wave's electric field in the regime of bubble-acceleration, was presented.
Abstract: We present the first well-resolved experimental observation of the non-linear formation of a laser-driven plasma wave, its breaking leading to self-injection and acceleration of electrons in the wave's electric field in the regime of “Bubble-acceleration”.