| 1. |
- Fullagar, Wilfred, et al.
(författare)
-
A broadband laser plasma X-ray source for application in ultrafast chemical structure dynamics
- 2007
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 78:11, s. 1-115105
-
Tidskriftsartikel (refereegranskat)abstract
- A plasma source free from characteristic emission lines is described, based on laser irradiation of a water jet in a helium atmosphere. Various key aspects of the laser interaction are presented along with practical characterization of the observed isotropic ~4–10 keV x-ray emissions, measurements of which indicate subpicosecond duration. Observations are consistent with a vacuum heating plasma mechanism at the helium-water interface and indicate strong potential for in-house ultrafast chemical structure dynamics application when coupled to contemporary detector developments.
|
|
| 2. |
- Fullagar, Wilfred, et al.
(författare)
-
Lab-based Ultrafast Molecular Structure.
- 2010
-
Ingår i: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. ; 1234, s. 919-922
-
Konferensbidrag (refereegranskat)abstract
- The proliferation of various laser-driven approaches to sub-picosecond hard X-ray and short-wavelength radiation generation in the past few decades has opened many avenues for the laboratory-based development of traditionally facility-based short wavelength ultrafast molecular structure science. Together with the introduction of microcalorimeter detection schemes, this opens the floodgates to widespread, decentralized implementation of what were until recently specialist short wavelength techniques. A parallel situation exists for the contemporary adoption of sub-wavelength resolution optical microscopies. In what follows, a few ultrafast molecular structure developments and their rationale are briefly recounted.
|
|
| 3. |
|
|
| 4. |
- Genoud, Guillaume, et al.
(författare)
-
Laser-plasma electron acceleration in dielectric capillary tubes
- 2011
-
Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 105:2, s. 309-316
-
Tidskriftsartikel (refereegranskat)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 5x10(17) W/cm(2). 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 mu m), 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.
|
|
| 5. |
- Uhlig, Jens, et al.
(författare)
-
Laser generated 300 keV electron beams from water
- 2011
-
Ingår i: Laser and Particle Beams. - 0263-0346. ; 29:4, s. 415-424
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in Undetermined300 keV electron beams with energy peaked in the range 280–390 keV were generated by focusing a high contrast ratio but temporally double pulsed 800 nm ultrafast laser onto a flowing water jet under both helium atmosphere at ambient pressure and water aspirator vacuum conditions, using laser intensities in the range 1015–1018 Wcm−2. Their characteristics have been investigated as functions of inter-pulse delay, incidence geometry and laser pulse chirp. Shot-to-shot variation of the beams' equatorial and azimuthal distributions was also recorded in real time. Measurements of the emitted charge and energy have been performed. Secondary X-ray emission arising from impingement of the electron beams on the target chamber walls and other parts of the apparatus have been identified. Preliminary results after transition to a high repetition rate laser system have shown similar behavior. Approaches for improvements and applications are suggested.
|
|
