Mechanism Analysis and Homogenization of Star-shaped Beam Profiles in Laser-Driven Proton Beamlines

摘要: Laser-driven proton accelerators have become a promising technology with applications ranging from cancer treatment to advanced imaging. At Peking University's CLAPA facility (Compact Laser-Plasma Accelerator), supported by China's Ministry of Science and Technology, researchers are developing medical-focused proton beam improvements. During CLAPA's beam transport system, we identified an unexpected star-shaped beam pattern forming after the beam collection section. If this distortion appears, it were not vanished without specialized treatment along the beam path. It significantly reduces beam quality and limits usability. Our study examines both how these star-shaped beams form and methods to control them. We present three effective solutions: beamline lattice reconfiguration, higher-order magnetic field beam shaping, and scatterer homogenization. This work provides essential guidance for improving beam control in same type of laser accelerator systems.