Real-time characterization of laser-accelerated protons using a scintillator stack

With the advent of laser technology, it has become possible to accelerate laser-driven protons up to the energies of tens of MeV, covering a large range of possible multidisciplinary applications (e.g. material science, medicine). One of the most common and reliable diagnostics for the dose and energy characterization of such particles is stacks of Radiochromic Films (RCF). Nevertheless, such detectors demand time-consuming post-irradiation processing and hence can provide the necessary information only “offline” after the laser shot. In recent years, however, it has become possible to reach a high repetition rate (>1 Hz) of laser operation, putting new challenges for diagnostics. In order to substitute such passive detectors as RCF stack while replicating their working principle in the “online” mode, scintillator materials have been investigated and tested. In this work, we present a compact and cost-effective device, capable of high-energy proton characterization in real time (currently in the range of 20-35 MeV). The detector can provide information about the energy of the proton beam and the Bragg curve distribution, based on analytical estimation and Monte Carlo simulations. The developed scintillator stack was compared with a standard RCF stack during the proof-of-principle test at a conventional accelerator under the same experimental conditions, showing a good signal agreement. Further tests at the laser facilities (e.g. at ELIMAIA (ELI Mulridiscriplinary Applications of laser-Ion Acceleration) user beamline at ELI Beamlines facility) are planned in the nearest future.