Time-resolved space-charge compensation studies for pulsed and matched proton beam in a low-energy transport line

Abstract

In low-energy beam transport of pulsed, high-perveance ion beams operating under neutralized spacecharge conditions, understanding the time required for the compensation process to develop-known as the build-up time-is critically important for ensuring efficient beam transmission and maintaining beam quality. This study presents a comprehensive investigation into the dynamics and optimization of spacecharge compensation (SCC) in the low-energy beam transport line of a high-perveance proton beam, integrating numerical simulations with time-resolved experimental measurements. A detailed 3D numerical simulation has been developed, which takes into account both secondary electron and ion dynamics to evaluate the temporal evolution of the beam potential and its dependence on various parameters. Additionally, experimental measurements complement the numerical results, providing validation of SCC dynamics. These measurements analyze the effects of injected gas properties, pressure levels, and beam current on build-up time, while also considering nonlinear space-charge effects that influence SCC efficiency and the beam's transverse emittance evolution. A correlation between SCC and radio-frequency quadrupole matching conditions is also examined, demonstrating the necessity of adjusting solenoid magnet settings to maintain optimal transmission efficiency.