Optical Fiber‐Based Sensors for Real‐Time Monitoring for Low‐Energy Proton Beams

This work presents the first results from our investigation regarding the potential use of radioluminescent Ce 3+ ‐doped silica‐based optical fibers as sensors capable of monitoring the flux of low‐energy (≤ 15 MeV) protons. This technology is shown as a promising candidate for dosimetry at the Centro Nacional de Aceleradores (CNA), offering improved precision and real‐time radiation monitoring during radiation test campaigns on microelectronics or photonics components and devices. Two proton beam lines have been used to characterize the fiber dosimeters in two different CNA facilities, using a 18/9 Cyclotron and a Tandem 3 MV accelerators. The calibration of the sensor for monitoring the proton flux at 15 MeV is currently reliable within a 24% margin, due to the presence of significant beam fluctuations that prevent a unique correlation between radioluminescence levels and the associated flux values. However, this result can be improved through additional tests aimed at refining the calibration process. When using 3 MeV protons, the signal exhibits an enhanced radioluminescence, confirming the high sensitivity of optical fibers to low‐energy protons. Physically relevant insights are obtained, as the compact geometry of the optical fiber makes it sufficiently embedded to detect the 3 MeV proton Bragg peak within its sensitive core region. Nevertheless, further investigations are needed to fully understand the radioluminescence mechanism, especially under the high‐dose rate conditions involved.