Radiation‐Induced Luminescence of a Medium‐OH Pure Silica Core Multimode Optical Fiber in Steady State and Pulsed X‐Ray Irradiations: Potential and Limitations for Dosimetry

A pure silica‐core (PSC) optical fiber (OF) with medium hydroxyl (M–OH) content, optimized for visible signal transmission in harsh radiation environments, is studied as a candidate for radiation‐induced luminescence (RIL) based dosimetry. The objective of this article is twofold: i) to evaluate whether this fiber can serve as a transport fiber for radioluminescence measurements when coupled to scintillating doped fiber probes and ii) to investigate its potential for standalone RIL‐based dosimetry, particularly for high dose rates and pulsed radiation applications. A dedicated experimental setup, developed to simulate X‐ray pulses, enables time‐resolved RIL measurements to investigate memory effects and the exploitability under high dose rates, close to the ones of FLASH radiotherapy treatments (>40 Gy/s). The M–OH PSC OF exhibits promising response for RIL‐based dosimetry, with a linear sensitivity increase with fiber length and significantly lower parasitic effects compared to the reference Ce 3+ ion doped fiber. Its use as transport fiber seems promising as well, thanks to its overall negligible RIL contribution supporting its use in high‐performance dosimetry systems.