Real-Time Beam Monitoring Device based on Cherenkov Effect for FLASH Radiotherapy Charged Particle Beams

A major barrier to the clinical implementation of FLASH Radiotherapy (FLASH-RT) is the lack of real-time beam monitoring. Conventional ionization chambers, the current standard, suffer from saturation and slow response times under ultra-high dose rate (UHDR) conditions. To address this limitation, we propose a novel Cherenkov-based beam monitoring chamber specifically designed for FLASH-RT.

Cherenkov emission is prompt (sub-nanosecond), linearly proportional to the number of beam particles and free from saturation effects. Our design replaces traditional ionization chambers with a thin in-beam Cherenkov radiator coupled to fast photodetectors. This configuration enables real-time monitoring of FLASH beams with sub-microsecond temporal resolution and no saturation effects.

In this thesis, we review the current state-of-the-art in beam monitoring technologies. We established a theoretical framework to assess key characteristics of our device, including the expected signal intensity and its potential impact on the beam. These results were further developed using Geant4 simulations. We expect our device has no saturation effects, minimal beam perturbation and sub-microsecond temporal resolution.