Quantitative elemental analysis of a specimen in air via external beam laser-driven particle-induced x-ray emission with a compact proton source

M. Salvadori, F. Brandi, L. Labate, F. Baffigi, L. Fulgentini, P. Galizia, P. Koester, D. Palla, D. Sciti, and L.A. Gizzi

Phys. Rev. Applied 21, 064020

Abstract

Particle-induced x-ray emission (PIXE) is a well-established ion-beam analysis technique, enabling quantitative measurement of the elemental composition of a sample surface under an ambient atmosphere with an external beam, which significantly simplifies the measurements, and is strictly necessary for those samples that cannot sustain a vacuum environment. Few-MeV electrostatic proton accelerators are used today in PIXE systems. We present here an external beam PIXE methodology based on a compact laser-driven proton accelerator. A 10-TW class ultrashort laser is used to generate a few-MeV proton beam, and a compact transport magnetic beamline is used to collect and transport the proton beam and to prevent unwanted fast electrons from reaching the sample. An x-ray CCD camera in single-photon detection mode is used to retrieve the spectrum of radiation emitted by the samples upon proton irradiation in air. Elemental composition analysis is performed and validated against standard energy-dispersive x-ray spectroscopy, demonstrating quantitative and accurate external beam PIXE analysis with compact laser-driven accelerators.