Bremsstrahlung X-Rays As A Non-Invasive Tool For Ion Beam Monitoring

Non-invasive beam monitoring tools are required to guarantee the delivered dose during ion irradiation. Measuring bremsstrahlung X-rays emitted directly from the irradiated medium is a promising approach. This work presents the feasibility of the method for different incident particles with different energies. A PMMA target was bombarded with helium ions of 68 MeV and protons beams of 30, 40, and 50 MeV. The bremsstrahlung signal, measured with a SDD, was in the magnitude of 104 X-rays/nC, indicating the significant sensitivity of the method. A good agreement was found (<6%) between the experimental and simulation bremsstrahlung spectra. For a thick target, the bremsstrahlung yield saturates and is directly proportional to the beam energy and the deposited dose at the surface. In addition, the bremsstrahlung spectrum shape contains information about the beam energy. Therefore, the bremsstrahlung signal gives access to the deposited dose and beam energy with precision depending on the experimental uncertainties.