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Applications of Laser-Plasma Acceleration

Svendsen, Kristoffer LU (2022)
Abstract
This thesis is dedicated to the investigation of laser-plasma particle acceleration concepts. Some of the work was focused on improving electron and proton acceleration for future applications, in terms of maximizing the particle energy and minimizing the divergence of the X-ray beams. In laser wakefield acceleration, a very intense laser pulse (> 1018 W/cm2) is focused in a gas. The leading edge of the pulse is intense enough to ionize the gas, and the main part of the pulse interacts with a plasma. Under the action of the ponderomotive force, the intense laser pulse can expel plasma electrons and form a wake in the plasma that trails the laser pulse. This charge separation leads to the formation of an ion cavity that results in... (More)
This thesis is dedicated to the investigation of laser-plasma particle acceleration concepts. Some of the work was focused on improving electron and proton acceleration for future applications, in terms of maximizing the particle energy and minimizing the divergence of the X-ray beams. In laser wakefield acceleration, a very intense laser pulse (> 1018 W/cm2) is focused in a gas. The leading edge of the pulse is intense enough to ionize the gas, and the main part of the pulse interacts with a plasma. Under the action of the ponderomotive force, the intense laser pulse can expel plasma electrons and form a wake in the plasma that trails the laser pulse. This charge separation leads to the formation of an ion cavity that results in electromagnetic fields several orders of magnitude stronger than those in conventional accelerators, up to TV/m. Some electrons can be accelerated to several hundred MeV over distances of less than a cm by injecting them into the plasma wake. There are also focusing forces inside the plasma wake, and the injected electrons will oscillate transversely about the optical axis, producing multi-keV betatron X-ray radiation. This radiation is directed along the optical axis with a low divergence of a few tens of mrad. One application investigated in this work was the possibility of using laser-wakefield-accelerated electrons for very high-energy electron (VHEE) radiotherapy. High-energy electrons can reach deep tumours with limited scattering, and have a more suitable dose-depth profile than photon beams. In this work, a VHEE beam was focused inside a phantom using electromagnetic quadrupoles to mimic stereotactic radiotherapy. The X-ray beam generated by LWFA was used to measure the equivalent path length and 3D liquid mass distribution in commercial fuel injectors by tomographic reconstruction. It was shown that the sensitivity (in terms of the detectable liquid mass) was comparable to that possible with large synchrotron facilities. Furthermore, the LWFA X-ray source is suitable for phase contrast imaging (PCI), a technique very sensitive to changes in the refractive index. In-line PCI was used to perform a high-resolution tomography of a small lacewing. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Kieffer, Jean Claude, INRS, Canada.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
laser wakefield acceleration, betatron radiation, X-rays, X-ray imaging, phase-contrast imaging, VHEE, radiotherapy, radiography, fuel injector, tomography, beam focusing, atomizing sprays, nanowires, liquid mass, target normal sheath acceleration, applications, charged particles
pages
173 pages
publisher
Atomic Physics, Department of Physics, Lund University
defense location
Lecture Hall Rydbergsalen, Department of Physics, Professorsgatan 1, Faculty of Engineering LTH, Lund University, Lund. Zoom: https://lu-se.zoom.us/j/68688243243?pwd=dnBYMTFxdkREMEE2eFBodEZqdXMvQT09
defense date
2022-02-11 09:15:00
ISBN
978-91-8039-143-6
978-91-8039-144-3
language
English
LU publication?
yes
id
6dfba8e5-76c4-4d7b-8ffa-278a18a3e3bf
date added to LUP
2022-01-17 15:15:49
date last changed
2022-01-20 12:46:25
@phdthesis{6dfba8e5-76c4-4d7b-8ffa-278a18a3e3bf,
  abstract     = {{This thesis is dedicated to the investigation of laser-plasma particle acceleration concepts. Some of the work was focused on improving electron and proton acceleration for future applications, in terms of maximizing the particle energy and minimizing the divergence of the X-ray beams. In laser wakefield acceleration, a very intense laser pulse (> 1018 W/cm2) is focused in a gas. The leading edge of the pulse is intense enough to ionize the gas, and the main part of the pulse interacts with a plasma. Under the action of the ponderomotive force, the intense laser pulse can expel plasma electrons and form a wake in the plasma that trails the laser pulse. This charge separation leads to the formation of an ion cavity that results in electromagnetic fields several orders of magnitude stronger than those in conventional accelerators, up to TV/m. Some electrons can be accelerated to several hundred MeV over distances of less than a cm by injecting them into the plasma wake. There are also focusing forces inside the plasma wake, and the injected electrons will oscillate transversely about the optical axis, producing multi-keV betatron X-ray radiation. This radiation is directed along the optical axis with a low divergence of a few tens of mrad. One application investigated in this work was the possibility of using laser-wakefield-accelerated electrons for very high-energy electron (VHEE) radiotherapy. High-energy electrons can reach deep tumours with limited scattering, and have a more suitable dose-depth profile than photon beams. In this work, a VHEE beam was focused inside a phantom using electromagnetic quadrupoles to mimic stereotactic radiotherapy. The X-ray beam generated by LWFA was used to measure the equivalent path length and 3D liquid mass distribution in commercial fuel injectors by tomographic reconstruction. It was shown that the sensitivity (in terms of the detectable liquid mass) was comparable to that possible with large synchrotron facilities. Furthermore, the LWFA X-ray source is suitable for phase contrast imaging (PCI), a technique very sensitive to changes in the refractive index. In-line PCI was used to perform a high-resolution tomography of a small lacewing.}},
  author       = {{Svendsen, Kristoffer}},
  isbn         = {{978-91-8039-143-6}},
  keywords     = {{laser wakefield acceleration; betatron radiation; X-rays; X-ray imaging; phase-contrast imaging; VHEE; radiotherapy; radiography; fuel injector; tomography; beam focusing; atomizing sprays; nanowires; liquid mass; target normal sheath acceleration; applications; charged particles}},
  language     = {{eng}},
  month        = {{01}},
  publisher    = {{Atomic Physics, Department of Physics, Lund University}},
  school       = {{Lund University}},
  title        = {{Applications of Laser-Plasma Acceleration}},
  url          = {{https://lup.lub.lu.se/search/files/112152186/Kristoffer_Svendsen_web.pdf}},
  year         = {{2022}},
}