Title Excitation of secondary radiation with high-intensity laser fields and its application in materials science /
Translation of Title Antrinės spinduliuotės žadinimas aukšto intensyvumo lazeriniais laukais ir jos taikymas medžiagotyroje.
Authors Tomkus, Vidmantas
DOI 10.15388/vu.thesis.135
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Pages 240
Keywords [eng] Laser Plasma Wakefield Accelerator ; Betatron radiation ; Plasma concentration profiles ; Micronozzle ; Laser fabrication of materials
Abstract [eng] In this thesis, the properties of electron beams and secondary X-ray radiation using high-intensity Laser Plasma Wakefield Accelerators (LWFA) and structured plasma concentration profiles in wiggler and injector geometry were studied. The energy and divergence of LWFA electron beams using Particle-in-Cell FBPIC code were numerically simulated. The results were post-processed for the estimation of the parameters of secondary betatron X-ray radiation. The supersonic gas jets of micronozzle arrays required the formation of plasma concentration profiles were modelled using OpenFOAM software of computational fluid dynamics. The micronozzle arrays were manufactured from fused silica using hybrid nanosecond laser rear-side machining and femtosecond laser-assisted selective etching (FLSE) technique. The experimental work was done using the 40 TW, 35 fs laser at the Lund Laser Centre. Using nozzle arrays in injector geometry and combined density down-ramp and ionization injection, quasi-monoenergetic electron bunches of 4-5 pC and 50±10 MeV were generated. The implementation of the betatron source with structured plasma concentration profiles in wiggler geometry raised the efficiency of X-ray generation and increased the number of photons per shot by a factor of 2 - 3 compared to a single-jet gas target. Electron energies of 30-150 MeV and 1.0×108 -5.5×108 photons per shot of betatron radiation have been measured.
Dissertation Institution Vilniaus universitetas.
Type Doctoral thesis
Language English
Publication date 2021