Improvement in radiation sensitivity of poly(methyl methacrylate) film dosimeters doped with Black100 via addition of sensitizers

Abstract

We fabricated poly(methyl methacrylate) (PMMA) films containing Black100 and trichloroacetic acid (TCA), tribromoacetic acid (TBA), or bis(t-butylsulfonyl) diazomethane, a photoacid generator (BTDPAG), as sensitizers and measured their absorption spectra before and after X-ray irradiation. The films containing TCA, TBA, and BTDPAG exhibited absorption peaks attributed to the oxidized form of Black100. In a previous study, radiochromism due to the oxidation of Black100 was not observed in PMMA films containing only Black100. These results indicate that Black100 underwent oxidation by radicals or acids generated from the sensitizers by X-ray irradiation. The sensitivities of the PMMA films containing Black100 and the sensitizers were 4.5–6.4 times higher than those of the films without sensitizers in the dose range of 0.1–1 kGy. Although this is the comparison of sensitivities at different tube voltages and dose rates, by adding sensitizers, the sensitivity of the PMMA films, which are compatible with three-dimensional (3D) printing, was about one-third that of the widely recognized 3D radiochromic dosimeter, PRESAGE.