Multidisciplinary evaluation of X-ray optical fiber sensors

• A X-ray sensor extrinsic optical fiber sensor was developed and characterized.
• X-ray fluorescence and radioluminescence investigations were carried out to evaluate sensor's performances.
• X-ray tomography was used to assess the distribution of active materials in the sensor's tip.
• The calibration of the sensor was performed against a professional dose rate meter.

We report the complex evaluation of an extrinsic optical fiber sensor for X-ray detection, consisting of different phosphor materials (ZnS:Ag, Gd2O2S:Pr, Gd2O2S:Eu, Gd2O2S:Tb) optically coupled to the end of a plastic optical fiber. X-ray fluorescence and radioluminescence measurements were used for the evaluation of sensors responsivity. The sensitivity and linearity of sensors response as a function of the X-ray source voltage and current were assessed. The dependence of the sensor responsivity on the irradiation dose rate was measured. X-ray radiography and tomography were employed to investigate the homogeneity of the active material distribution inside the detecting tip. The most sensitive sensor proved to be that based on Gd2O2S:Tb, fixed with the EpoFix glue and manufactured using a plastic cylinder to shape the sensor tip.