| 1. |
- Torrisi, Lorenzo, et al.
(författare)
-
Proton driven acceleration by intense laser pulses irradiating thin hydrogenated targets
- 2013
-
Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 272, s. 2-5
-
Tidskriftsartikel (refereegranskat)abstract
- The Asterix iodine laser of the PALS laboratory in Prague, operating at 1315 nm fundamental frequency, 300 ps pulse duration, 600 J maximum pulse energy and 1016 W/cm2 intensity, is employed to irradiatethin hydrogenated targets placed in high vacuum. Different metallic and polymeric targets allow togenerate multi-energetic and multi-specie ion beams showing peculiar properties. The plasma obtainedby the laser irradiation is monitored, in terms of properties of the emitted charge particles, by using time-of-flight techniques and Thomson parabola spectrometer (TPS). A particular attention is given tothe proton beam production in terms of the maximum energy, emission yield and angular distributionas a function of the laser energy, focal position (FP), target thickness and composition.
|
|
| 2. |
- Torrisi, Lorenzo, et al.
(författare)
-
High intensity laser-generating plasmas in forward direction in thin films and Thomson parabola spectrometer monitorage
- 2010
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Asterix laser at PALS Laboratory of Prague, operating at 1315 nm fundamental wavelength, 300 ps pulse duration, 1016 W/cm2 intensity and single pulse mode, was employed to irradiate thin hydrogenated targets placed in high vacuum. Non-equilibrium plasmas were obtained in forward direction, i.e. along the normal to the target surface on the rear of the irradiated thin films. Plasmas were monitored with different ion detectors, placed around the direction normal to the target. The main detector was a Thomson parabola spectrometer aligned along the normal in forward direction. This spectrometer permits to provide many plasma parameters concerning the involved ions (energy, charge state, mass,...) obtained in a single laser shot. The spectrometer images, obtained by using a MCP coupled to a fast CCD camera, can be processed by a comparison with the simulation data obtained by a proper software. High ion energies and charge states have been obtained as a function of the laser parameters, target thickness and composition and irradiation conditions.
|
|
| 3. |
- Badziak, J., et al.
(författare)
-
Application of ion diagnostics to control the laser-induced removal of surface layer of a carbon substrate
- 2006
-
Ingår i: Plasma 2005. - : AIP. - 073540304X ; , s. 295-298
-
Konferensbidrag (refereegranskat)abstract
- Among other methods of detritiation of in-vessel tokamak components the application of lasers for removal of fuel trapped in co-deposited layers is under investigation. The paper presents preparation and tests of ion diagnostic methods for on-line measurement of the amount and characteristics of ablated carbon, hydrogen/deuterium and contaminant species from the graphite target (plate) of the main toroidal limiter of the TEXTOR tokamak. For removal of the surface layer from the graphite limiter plate Nd:YAG laser was used. Determination of the characteristics of laser-produced ions has been performed by means of ion collectors and an electrostatic ion-energy analyser. The main ion stream parameters were measured depending on the number of laser shots and the laser power density on the target surface. The properties of modified carbon sample surface were determined with the use of optical methods and compared with the results of the ion measurements.
|
|
| 4. |
- Gasior, P., et al.
(författare)
-
Characterization of laser-irradiated co-deposited layers on plasma facing components from a tokamak
- 2006
-
Ingår i: Physica Scripta. - 0031-8949 .- 1402-4896. ; T123, s. 99-103
-
Tidskriftsartikel (refereegranskat)abstract
- An experimental setup and ion diagnostic method for laser-induced fuel removal and decomposition of co-deposited layers on plasma facing components from tokamaks are described. Nd:YAG 3.5 ns pulse laser with a repetition rate of 10 Hz and single-pulse energy of up to 0.8J at 1.06 mu m has been used for irradiation of a graphite limiter tile from the TEXTOR tokamak. Comparative studies have been performed for a pure graphite plate as a reference target. Energy of emitted ions has been measured using a time-of-flight method. Early results show that laser pulses efficiently ablate the co-deposit removing both fuel species and heavy components such as Si, Ni, Cr, Fe and W present in the layers. Surface topography of the irradiated targets is also presented.
|
|
| 5. |
- Torrisi, Lorenzo, et al.
(författare)
-
Single crystal silicon carbide detector of emitted ions and soft x rays from power laser-generated plasmas
- 2009
-
Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 105, s. 123304-1-123304-7
-
Tidskriftsartikel (refereegranskat)abstract
- A single-crystal silicon carbide SiC detector was used for measurements of soft x rays, electrons, and ion emission from laser-generated plasma obtained with the use of the Prague Asterix Laser System PALS at intensities of the order of 1016 W/cm2 and pulse duration of 300 ps. Measurements were performed by varying the laser intensity and the nature of the irradiated target. The spectra obtained by using the SiC detector show not only the photopeak due to UV and softx-ray detection, but also various peaks due to the detection of energetic charged particles. Time-of-flight technique was employed to determine the ion kinetic energy of particles emitted from the plasma and to perform a comparison between SiC and traditional ion collectors. The detector was also employed by inserting absorber films of different thickness in front of the SiC surface inorder to determine, as a first approximation, the mean energy of the soft x-ray emission from the plasma.
|
|
| 6. |
- Badziak, J, et al.
(författare)
-
Generation of ultraintense proton beams by multi-ps circularly polarized laser pulses for fast ignition-related applications
- 2011
-
Ingår i: Physics of Plasmas. - New York : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 18:5
-
Tidskriftsartikel (refereegranskat)abstract
- A scheme of generation of ultraintense proton beams relevant for proton fast ignition (PFI) which employs multi-ps, circularly polarized laser pulse irradiating a thick (≥ 10 μm) H-rich target is proposed and examined using one-dimensional particle-in cell-simulations. It is shown that a 5-ps laser pulse of intensity ∼ (2–5) × 1020W/cm2 irradiating the target of the areal proton density ∼ 2 × 1020cm−2 can produce – with a high energetic efficiency – a proton beam (plasma block) of parameters (intensity, energy fluence, pulse duration, proton energy spectrum) close to those required for PFI. At a fixed total laser energy, the proton beam parameters can be controlled and fitted to the PFI requirements by changing the laser intensity (energy fluence) and/or the target thickness as well as by using a shaped (curved) target inserted into a guiding cone.
|
|
