Spectral study of the lateral trace-space of laser-driven proton beams

The characterization of the phase space of laser-driven proton beams—particularly across a broad energy spectrum—in spite of the recent interest in laser-driven particle accelerators, remains a significant challenge due to the complex interplay between transverse dynamics and spectral properties. This work presents a detailed spectral study of the lateral emittance of laser-driven proton beams, providing energy-resolved, single-shot measurements of the beam emittance by means of a magnetically streaked pepper-pot method. Experimental results from a laser-driven proton source demonstrate the ability to resolve the beam’s transverse trace space at various proton energies, yielding precise emittance estimations and highlighting the variation of beam quality with energy. The study emphasizes the necessity of high spectral resolution for accurate emittance characterization. The findings offer valuable implications for optimizing beamline design and improving the performance of future tabletop laser accelerators.