Liquid-core optical waveguide dosimetry. An experimental study of a simple measurement system with LED and photodiode

For the simple liquid-core optical waveguide dosimeter (consisting of: LED-OWG dosimeter-neutral OWG-photodiode), changes of the light spectrum transmitted through the OWG dosimeter were studied as a function of absorbed dose (from 1 to 10 Gy). From these spectral data (differential approach) the values of absorbance vs dose, as if they were measured with a photodiode, were derived, and intercompared with the directly measured ones by a PIN photodiode (integral approach). The agreement was better than ±5%. The influences of errors in optical misalignment, “dark” current, light intensity reading were quantitatively estimated and discussed.