Preliminary investigations of several new dyed PMMA dosimeters

Abstract

Radiochromic dosimeters such as Red 4034 Perspex and Gammachrome YR show good performance in the absorbed dose control quality in industrial radiation processes. Aiming to develop a sensitive, useful, practical and cheep dosimeter, dyed Polymethylmethacrylate (PMMA) sheets using yellow, red, blue and green colouring compounds, commercially available in Brazil, were developed and the dosimetric properties related to ionizing radiation were studied. Small pieces of 1 3 cm2 of dyed PMMA were cut, cleaned, sealed in special pouches and irradiated with 60Co gamma doses between 0.5 and 100 kGy. The ionizing radiation effects on the optical properties were evaluated by means of spectrophotometric analysis. The studied parameters were: absorption spectra of irradiated and nonirradiated samples, batch reproducibility, dose response, thermal and optical fading and dose rate dependence between 0.49 and 4.9 kGy/h. The obtained results show the viability of using these developed dosimeters for dose evaluation in industrial gamma radiation processes.