Flat foils as UV and ionising radiation dosimeters

Abstract In this work we discuss UV and ionising radiation induced processes in the flat foils (films). The foils were made from poly(vinyl alcohol) (PVA) and either 10,12-pentacosadiynoic acid (PDA) or a representative of tetrazolium salts − 2,3,5-triphenyl tetrazolium chloride (TTC). Also, we proposed a very attractive modification of the surfaces of the foils by vapour deposition of parylene C. This lead to an alteration of the UV dose response of the foils and improved their water-resistance thus making them potentially useful for radiation dose measurements when immersed in water. The TTC- and PDA-containing foils were shown to respond to ionising radiation in a high dose range of up to 3 kGy. The PDA foils were of a higher dose sensitivity and much lower dose threshold than those containing TTC. Whereas the TTC-containing foils were of irreversible character, those containing PDA showed high reversibility both to UV and ionising radiation. Basic features of such reversible-foil dosimeters are presented. Additionally, the mechanism of radiation induced changes in the TTC- and PDA-PVA films is analysed by using UV–vis spectrophotometry and Raman spectroscopy techniques.