Design and implementation of the first proton beamline in VEGA-3 Petawatt laser system.

Abstract Laser-Plasma ion acceleration is acquiring importance on a daily basis due to incipient applicability in certain research fields.However, the energy and divergence control of these brilliant sources can be considered a bottleneck in the developmentof some applications. In this work, we present the commissioning of a compact proton beamline based on a triplet ofquadrupoles dedicated to focus and collect short and energetic pulses, open to the user community. The focused proton beamcharacterization has been carried out by imaging of scintillation detectors with different particle filters. Experimental resultshave been compared with numerical simulations performed with Monte Carlo code (MCNP6) and T-STEP that have been usedto perform the deposited energy, the particle tracking, and the particle distribution in different focal configurations, respectively.Charges of nC (∼1010protons with energies up to 17.25 MeV) have been measured at the focal planes compacting the thebeam to spot sizes of a few millimetres in RMS (root mean square). The percentage fluctuation of the transported chargesvalues has been studied. The beam rigidity has been measured by transverse moving of the quadrupoles and subsequentbeam centroid shift, allowing to cross correlate the deflected energy with the energy ranges resulting from the filtering process.Finally, the versatility of the system, which is also suitable for operating at high repetition rate (HRR), has been demonstratedby proton beam lithography tests using a mask.