Radiation Resistance of Ge-doped Multi-Mode Fiber for Optical Links in Collider Experiments

TL;DR

This study evaluates the radiation tolerance of Ge-doped multi-mode fibers for optical links in collider experiments, demonstrating their suitability for high-ionizing dose environments with minimal attenuation and effective recovery.

Contribution

It provides experimental data on radiation-induced attenuation, dose rate dependence, and temperature effects for Ge-doped fibers, highlighting their potential for high-energy physics applications.

Findings

Ge-doped fibers show low RIA of 0.05 dB/m at 300 kGy

Radiation effects are recoverable within hours after shielding

Temperature and dose rate have limited impact on long-term RIA levels

Abstract

The applications of optical links in collider experiments provide the advantage of high-speed data transmission with low mass fibers over distances of a few hundred meters. Ge-doped multi-mode fibers are evaluated for radiation tolerance in ionizing doses of Co-60 gamma rays. The Radiation-Induced Attenuation (RIA) varies significantly depending on doping substances and fabrication technologies. A type of telecom-grade fiber has demonstrated an RIA of 0.05 dB/m under a total ionizing dose of 300 kGy(SiO2). The dependence on dose rate is compared in the range between 5 Gy/hr and 1.4 kGy/hr, and the annealing recovery is observed after the Co-60 source is shielded. The temperature dependence is investigated across a range of -15 oC to room temperature. At cold temperatures, stagnant annealing leads to a substantially higher RIA during irradiation. The recovery of radiation-induced defects is typically within a few hours, resulting in similar RIA levels regardless of the dose rate and temperature during exposure. Ge-doped fibers of chosen fabrication methods are capable of enduring high ionizing doses for use in high-energy physics experiments.