Distribution uniformity of laser-accelerated proton beams

TL;DR

This paper discusses the design and optimization of a beamline system for laser-accelerated proton beams to achieve uniform, radially symmetric distributions suitable for various applications, including biological and astrophysical research.

Contribution

It introduces a carefully designed beamline system with optimized parameters to produce uniform, radially symmetric proton distributions from laser-accelerated sources.

Findings

Achieved radially symmetric proton distributions with optimized beamline parameters.

Protons with different energy spreads within 5% have similar transverse areas.

Demonstrated the influence of energy selection and focusing on proton distribution evolution.

Abstract

Compared with conventional accelerators, laser plasma accelerators can generate high energy ions at a greatly reduced scale, due to their TV/m acceleration gradient. A compact laser plasma accelerator (CLAPA) has been built at the Institute of Heavy Ion Physics at Peking University. It will be used for applied research like biological irradiation, astrophysics simulations, etc. A beamline system with multiple quadrupoles and an analyzing magnet for laser-accelerated ions is proposed here. Since laser-accelerated ion beams have broad energy spectra and large angular divergence, the parameters (beam waist position in the Y direction, beam line layout, drift distance, magnet angles etc.) of the beamline system are carefully designed and optimised to obtain a radially symmetric proton distribution at the irradiation platform. Requirements of energy selection and differences in focusing or defocusing in application systems greatly influence the evolution of proton distributions. With optimal parameters, radially symmetric proton distributions can be achieved and protons with different energy spread within 5% have similar transverse areas at the experiment target.