Theoretical Limit of the Color‐Change Sensitivity of a Composite Resin Dosimeter Film Based on Spiropyran/BaFCl : Eu2+/Polystyrene

• Published in: ChemistryOpen (Weinheim) Vol. 9; no. 5; pp. 623 - 627
• Main Authors: Kinashi, Kenji, Tsuchida, Hayato, Sakai, Wataru, Tsutsumi, Naoto
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley and Sons Inc 01-05-2020; Wiley-VCH
• Subjects: Color dosimeters; Composite resin dosimeter; photochromism; radioactivity; spiropyrans
• ISSN: 2191-1363; 2191-1363
• DOI: 10.1002/open.202000071

The theoretical limit of the color‐change sensitivity of a composite resin dosimeter film based on 6‐nitro BIPS/BaFCl : Eu2+/polystyrene under X‐ray exposure has been estimated. Each photophysical and photochemical process occurring inside the composite resin dosimeter was quantitatively determined, and the obtained values were used to estimate the theoretical limit of the color‐change sensitivity for the composite resin dosimeter. The values obtained were 70.6 % for the X‐ray absorption efficiency, 13 % for the fluorescence quantum yield, 73.5 % for the UV absorption efficiency and 37.6 % for the photochemical quantum yield. Assuming that the figure‐of‐merit is their product, its value is estimated to be 2.5 %, which contributes to the chromaticity difference and leads to a color‐change sensitivity of 100 mGy. The figure‐of‐merit of a structurally optimized composite dosimeter was estimated to be 1.9 times that of the dosimeter without structural optimization, which showed a sensitivity of 100 mGy. We predicted that the structurally optimized composite resin dosimeter film, which eliminates optical losses due to the structure, will be able to detect X‐ray exposure doses on the order of approximately 28 mGy.
Take it to the limit: The theoretical limit of color‐change sensitivity under X‐ray exposure for a composite resin dosimeter film based on 6‐nitro BIPS/BaFCl : Eu2+/polystyrene was evaluated using a figure‐of‐merit taken into account photophysical and photochemical processes occurring in the film. The theoretical limit of color‐change sensitivity for the composite resin dosimeter is be expected to be approximately 28 mGy.