Speaker
Description
FLASH proton therapy, enabled by ultra-high dose rates, offers enhanced tumour control with reduced damage to healthy tissue. Laser-driven proton sources are a promising compact solution, but their intense, pulsed beams pose challenges for conventional beam diagnostics. This work presents a minimally invasive real time diagnostics of such beams using gas-jet-based ionization profile monitor. It uses a thin gas-screen placed along the beam path, inside the vacuum, and captures beam-induced ionization on a Micro-Channel Plate (MCP) which is imaged via a CMOS camera.
The system was tested at the MC40 Cyclotron facility at University of Birmingham for various shape and sizes of proton beam with energy between 10.8-28 MeV at different beam currents. It demonstrated beam profile measurements within a few 100 ms. Further developments were made to make the system compact to facilitate the integration into medical accelerators. These developments were followed by CST simulations to configure the system which showed improved electric field uniformity, with 85% detection efficiency. The simulations showed that the fluctuations in the beam position can be monitored. It also revealed that the energy inhomogeneity in the extracted ions can be ±7% for beam sizes ≥10 mm which introduces profile distortion. Simulations can provide a parameter to account for this distortion to generate accurate beam profiles. The existing system is compatible with beam sizes up to 40 mm, encompassing the clinically relevant range. Further design improvements will be investigated to accommodate larger beam sizes for wider applications in ion beam therapy.
This work advances beam instrumentation for compact, high-intensity laser-driven proton/ion sources, addressing key challenges in beam diagnostics and control, critical to the development of next-generation accelerators and applications.
