Thermoluminescence responses of the Yb- and Yb–Tb-doped SiO2 optical fibers to 6-MV photons

•SiO2 fibers doped with Yb and Yb+Tb can be used as thermoluminescence dosimeters.•The TL response to the dose is linear in the range 0.5–4.0 Gy.•The radiation sensitivity of the Yb–Tb-doped material is much higher than the sensitivity of the Yb-doped one.•Minimal detectable doses with the fibers doped with Yb and Yb+Tb are 333 and 19 mGy, respectively.

Characteristics of the thermoluminescence (TL) responses of Yb- and Yb–Tb-doped optical fibers irradiated with 6 MV photons are reported. The concentration of Yb in the Yb-doped optical fiber was 0.26 mol%; the concentrations of Yb and Tb in the Yb–Tb-doped optical fiber were 0.62 and 0.2 mol%, respectively. The TL dose responses are linear in the dose range 0.5–4 Gy. The radiation sensitivity of the Yb–Tb material is almost two orders of magnitude higher than the sensitivity of the material doped with Yb alone.