J. Cruz-Castañeda, A. L. Meléndez-López, A. Heredia, S. Ramosbernal, and A. Negrón-Mendoza
dosimeter, carboxylic acid, gamma radiation, ATR-FT-IR spectroscopy
|PUBLISHED DATE||August 6, 2018|
|PUBLISHER||The Author(s) 2018. This article is published with open access at www.chitkara.edu.in/publications.|
The intensive use of ionizing radiation has promoted the constant investigation of adequate dosimetric systems in the measurement of doses applied in irradiated products. The objective of this work is to propose gamma dosimetric systems, using carboxylic acids in a solid state and measuring the change via infrared spectroscopy (carboxylic acid/ ATR-FT-IR1). We worked with three systems: (1) behenic acid/ATR-FT-IR, (2) sebacic acid/ATR-FT-IR, and (3) fumaric acid/ATR-FT-IR. The change in absorbance corresponding to the stretching vibration frequency of the carbonyl group to the absorbed dose (in the range of kGy) was measured. The results showed that the acid/ATR-FT-IR systems have a linear response with respect to the absorbed dose, for behenic acid/ATR-FT-IR from 0 to 122 kGy, for ATR-FT-IR sebacic acid from 0 to 61 kGy, and for fumaric acid/ATR-FT-IR from 0 to 34 kGy. The results indicated that the linear response of the absorbance dose in the three systems allows us to continue studying other variables to be able to propose them as chemical dosimeters
Different chemical dosimetry systems have been proposed. The most popular is the Fricke dosimeter, measured via UVVIS spectrophotometry at 304 nm . Other dosimeters are based on the use of amino acid films on PET2 measured by EPR3, such as the alanine dosimeter  or the aspartic acid dosimeter . However, no universal dosimeter exists due to the different physical and chemical variables of each dosimetric system—for example, temperature, sensitivity, linear response interval, analysis time, type of radiation, etc. For this reason, it is crucial to investigate diverse possible dosimetry systems to be able to measure doses in various circumstances. Several authors studied the stability of carboxylic acids against gamma radiation. Their primary decomposition in the solid state via gamma radiolysis is a decarboxylation reaction, forming a corresponding hydrocarbon with one fewer carbon atom and carbon dioxide (CO2) [4-5], with radiochemical yield G (CO2) values of about 3 . The objective of this work is to propose dosimetric systems for gamma radiation using carboxylic acids, specifically behenic acid (C22H44O2), sebacic acid (C10H18O4), and fumaric acid (C4H4O4), measuring in the signal corresponding to the carbonyl bond stretch (C = O) monitored by ATR-FT-IR spectroscopy. For this purpose, the change in absorbance corresponding to the stretching of the carbonyl bond (C = O) was measured via ATR-FT-IR spectroscopy at 1700 cm-1 for behenic acid, 1685 cm-1 for sebacic acid, and 1660 cm–1 for fumaric acid. The results indicated that carboxylic acid-ATR-FT-IR systems show a linear response to the dose of gamma radiation from Gy to the order of kGy at room temperature (20°C).
|ISSN||Print : 2321-8649, Online : 2321-9289|