Operating Temperature Range of Phosphorous-Doped Optical Fiber Dosimeters Exploiting Infrared Radiation-Induced Attenuation

Point or distributed optical fiber (OF)-based dosimeters can exploit the observed linear dependence of the radiation-induced attenuation (RIA) at 1550 nm in phosphosilicate OFs to monitor the total ionizing dose (TID). The temperature dependence of the radiation sensitivity coefficients at 1550 nm (expressed in dB km$^{-1}$ Gy$^{-1}$) of three phosphorus-doped single-mode OFs has been investigated between -80 °C and 300 °C for TID ranging from 1 Gy to 1 kGy(SiO$_2$). Our measurements reveal the same temperature dependence of the calibration factor for the three fibers at the higher temperatures (>120 °C) where the P1 defects, at the origin of the IR-RIA, are metastable. However, the uncertainties on the TID measurements through the fiber-based dosimeter remain within the 15% for temperatures ranging from -80 °C to 120 °C for the three tested fibers. The independence of the RIA and then of the dose measurements from the dose rate is also maintained in this temperature range.