A solid-state polymeric dosimeter has been developed. The solid-state dye-doped polymeric dosimeter comprises the photo-curable polymer materials Poly(ethylene glycol)-diacrylate (PEGDA) and 2-Hydroxyethyl-methacrylate (HEMA) and the radiochromic leuco-dye 4,4′,4″- Triamino-triphenyl –acetonitrile. Using a photo-curable polymer blend facilitates a tight control of the polymerization process and hence the properties of the solid-state dosimeter. The radiation sensitive leuco-dye responds to ionising radiation by forming a stable free radical – a triphenylmethyl dye. This free radical has strong colour, and is fluorescent because it is dissolved in the solid polymeric material. Both physical properties can be measured optically. The free radical, however, provides a third signal as it is paramagnetic and hence can be detected by means of Electron Paramagnetic Resonance (EPR) spectroscopy. The EPR signal makes it possible to measure the radiation-induced free radical signal free from optical artefacts of the polymer material. Results from irradiations using a low-dose-rate cobalt-60 gamma irradiator shows an EPR signal measured using a Bruker EMX EPR spectrometer for the solid polymeric dosimeter, whose peak-to-peak amplitude is linear with the dose in the medical dose range and saturates for higher doses (100 Gy).
- 3D dosimetry
- Solid-state polymer dosimeter
- Pararosaniline leuco dye
- Free radical