Development of an acoustic dose-profile measurement technique for short pulse proton and ion beams

Cancer is the second leading cause of death globally, with radiotherapy treating about 50\% of patients. Conventional radiotherapy uses photons, however, it often irradiates healthy cells surrounding the cancerous region. New treatment facilities are turning to protons and light ions, which deposit a maximum dose within a small volume at the end of their range. This thesis introduces LhARA, the Laser-hybrid Accelerator for Radiobiological Applications, which aims to advance radiobiology by exploring how different particle beam characteristics affect therapeutic outcomes. Using pulsed proton and light-ion beams, LhARA offers flexibility in ion species, beam widths, and pulse duration. To minimize uncertainties, real-time dose delivery monitoring is essential. This work presents the SmartPhantom, a novel detector for monitoring three-dimensional dose accumulation delivered using nanosecond-scale ion beam pulses. Unlike existing devices that provide only relative dose values, the SmartPhantom delivers calibrated feedback. The detector uses ultrasound waves induced by the transient pressure increase as the beam propagates through matter. Due to the high speed of ultrasound, feedback is nearly instantaneous. To calibrate the acoustic response, a liquid scintillator is used as the propagating medium inside the detector. The scintillation light emitted during beam propagation, combined with known photon yields, enables absolute dose reconstruction. The SmartPhantom was evaluated at the MC40 cyclotron in Birmingham and the LION accelerator at CALA in Munich. To optimize the design, a simulation pipeline was developed using Python for source parametrization, BDSIM for particle tracking, Geant4 for energy deposition calculations, and Matlab for acoustic modeling. The results revealed strong correlation between optical and acoustic measurements, validating the detector's potential. This lays the foundation for a clinically viable, real-time dose monitoring system.