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Title: Laser ion acceleration from ultrathin foils and application to radiobiology
Author: Hanton, Fiona
ISNI:       0000 0004 6058 3754
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2016
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Laser driven ion sources offer a potential alternative to conventional ion accelerators currently used in hadrontherapy for cancer treatment. The unique characteristics of the ion beams sets the basis for development toward therapeutic use. The work presented in this thesis seeks to overcome the present limitations of laser-driven ion accelerators and to demonstrate the ion beam parameters required to make this a viable treatment option. Ultra-thin copper and gold foil targets were irradiated with intense laser pulses at normal incidence by varying laser and target parameters. For copper, the peak ion energies were observed to quadratically scale with the dimensionless fluence parameter, suggesting efficient Radiation Pressure Acceleration in the Light Sail phase in a hybrid acceleration regime. For gold targets, the production of high peak ion energies of ~20 MeV, ~12 MeV/nucleon and 7.5 MeV/nucleon for H+, C6+ and Au45+ were observed, respectively. In particular, the Au45+ ion energies translate to approximately 1.5-2 GeV per Au ion (for energies exceeding and including the spectral peak). 2D PIC simulations were performed and were found to be in agreement with experimentally observed data. The radiobiological work focused on studying DNA Double Strand Breaks (DSBs) following the irradiation of AG01522 cells with proton and carbon ions at ultra-high dose rates of ≥10A˄9 Gys˄-1. This was done by quantitatively measuring the dispersion of 53BP1 foci over a 24 hour period for cells irradiated with 10 MeV (5 keV/μm) protons and 5 MeV/nucleon (310 keV/μm) carbon ions. The slow repair kinetics and large number of foci remaining at 24 hours from carbon ion irradiation was indicative of more severe DSBs compared to the lower LET exposure from protons. The relative biological effectiveness for protons and carbon ions were found to be RBE_1H = 1.6 ± 0.2 and RBE_12C = 13 ± 9.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available