Potential of Copper- and Cerium-Doped Optical Fiber Materials for Proton Beam Monitoring

We investigate the potential of innovative optical fiber bulk materials made by the sol-gel technique for real-time proton beam monitoring. Those types of glass are made of amorphous silica (<inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula>-SiO₂) doped with either Copper (Cu) or Cerium (Ce) ions. These optimized materials possess very interesting light emission properties when exposed to protons. For both types of glasses, online monitoring of the strong radiation-induced luminescence (RIL) allows to monitor the time evolution of the proton flux with <inline-formula> <tex-math notation="LaTeX">${ms}$ </tex-math></inline-formula> resolution and the cumulated proton fluence can be precisely deduced by integrating the RIL signal. Furthermore, we showed that both samples present optically-stimulated luminescence (OSL) that could be exploited shortly after the end of the irradiation to reconstruct the cumulated fluence too. Preliminary tests presented in this paper have been performed at TRIUMF facility with high energy (30 - 63 MeV) protons at flux and fluences representative of proton therapy treatments. Obtained results demonstrate the potential of the developed optical materials for proton beam monitoring and permits to identify the needs for future experiments on microstructured fibers elaborated from these optical materials.