Proton Dosimetry Using Radiation-Induced Luminescence in Micrometer-Core Germanosilicate Optical Fibers

We investigated the radiation-induced luminescence (RIL) of 62.5, 10, and
$3~\mu \text{m}$
germanosilicate single- and multi-mode telecom-grade optical fibers for use as high-resolution dosimeters at dose rates ranging between 5 and 120 Gys
$^{-1}$
using proton beams of varying currents and energies. Only one of the two single-mode fibers under investigation had a detectable light yield, with a dose rate threshold around 20 Gys
$^{-1}$
. All tested multi-mode fibers showed a detectable response over the whole accessible dose rate range. All tested multi-mode fibers displayed a linear dose rate response when the proton beam energy was fixed. However, the slope of the response curve showed a strong dependence on the proton beam energy. Geometry and material differences, as well as radiation-induced attenuation (RIA) effects have been ruled out as sources for the observed proton energy dependence of the dose rate response.