. Dosimetric Evaluation And Radiation Induced Structural Change In Polymer Based Radiochromic Film (original) (raw)
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Polymers
This study investigated the polymer film composite of polyvinyl alcohol (PVA), trichlorethylene (TCE) and cresol red (CR) dye irradiated with gamma (γ) rays for potential application as radiation dosimetry. The film was prepared via the solvent-casting method with varying concentrations of TCE. Film samples were exposed to radiation from a γ-rays radiation source of 60Cobalt isotope. Color changes before and after γ-rays irradiation were observed, and the optical properties of the polymer films were investigated by spectrophotometry. Results show that increasing the radiation dose physically changed the color of the polymer film, from purple (pH > 8.8) without radiation (0 kGy) to yellow (almost transparent) (2.8 < pH < 7.2) at the highest dose (12 kGy). The concentration of acid formed due to irradiation increased with the increase in irradiation doses and at higher TCE content. The critical doses of PVA-TCE composites decreased linearly with the increase of TCE compositio...
To Determine Dose Response Curves of Dyed Polyvinyl Alcohol Films Irradiated with Gamma-Rays
Open Journal of Safety Science and Technology, 2018
The Polyvinyl Alcohol (PVA) films dyed with different colors such as methylene blue (MB), methyl orange (MO), methyl red (MR) and crystal violet (CV) were investigated. The dyed PVA films were irradiated by with Co 60 γ-source in dose range of 1-150 kGy. The optical density change in these films at pre and post irradiation was studied by spectrophotometer. The gamma dose response curves of the dyed PVA films were described by saturated exponential function of the energy transfer model with high correlative coefficient. The color sensitivities on the dyed PVA films irradiated by source were different. The PVA films dyed with MB had the highest sensitivity.
Radiation Induced Decoloration of Reactive Dye in PVA Films for Film Dosimetry
Journal of Basic & Applied Sciences, 2021
The investigation of film dosimeters made from polyvinyl alcohol (PVA) films dyed with methyl orange (MO) to enable their use in high dose radiation processing applications was studied. The dosimetric change in these films at pre and post irradiation was studied spectrophotometrically. Radiolytic bleaching was observed in PVA aided films exposed with Cs137 γ-source in dose range of 100-200kGy. The effects of pH, dye concentration and film thickness on the radiation response of the film dosimeters were discussed. The stability of MO-PVA films before and after exposure of radiation was also examined at ambient temperature and was found to be higher for long times at pre and post irradiation stages.
Optical and Mechanical Properties of PVA Films using Spectrophotometry & XRD Techniques.
Polyvinyl-alcohol based reactive red 195-A films (PVA-R) were irradiated by Cs 137 γ-source in the range of 200 Gy-10 5 Gy. The effects of gamma irradiation on optical and mechanical properties of PVA-R were studied using spectrophotometry and x-ray diffraction (XRD) technique to check its feasibility in radiation processing. The found values of the λmax and the molar extinction coefficient of the dye were 520 nm and 48 Lgm -1 mm -1 respectively. Parameters such as effect of dye concentration and pH values, Electrical Conductivity, % decoloration, Strain , % crystallinity, crystallinity Index (C.I.) and crystallite size (d) have been selected for the dosimetric and mechanical strength evaluation. Linearity between specific absorbance and absorbed dose showed that acidic samples of PVA-R films can be better chemical dosimeter as compared to alkaline ones in dose range of 200 Gy-10 kGy. At high dose i.e., 100 kGy of gamma irradiation, change in mechanical strength was found due to decrease in crystallinity, crystallite size and increase in strain values.
2004
The influence of y-rays on the optical absorption and inelastic scattering, dielectric properties and conductivity of radiation-sensitive dyed polyvinyl alcohol (TBIPVA) film dosimeters containing chloral hydrate and acid-sensitive Thymol blue dye were evaluated for possible use as food irradiation indicators. The dyed PVA films of different concentrations of chloral hydrate were irradiated with the absorbed doses ranging up to 12 kGy using y-rays from Cobalt-60. The dehydrochlorination of chloral hydrate and radiolysis of water molecules induced by ionising radiations accelerated the formation of hydrochloric acid in the polymer matrix, which caused the change in colour of the dosimeters from yellow to red at the critical doses depending on the concentration of chloral hydrate. This radiation-induced colour change was analysed using UV-Vis spectrometer, where the absorption spectra produced two visible maximal bands, peaking at 445 nm and 554 nm. The dose response at 445 nm and 554...
Comparative study of two mixture dyes based on PVA for industrial use as gamma radiation dosimeter
s10967-023-08854 -z., 2023
New film dosimeters PVA/(DCP/CR) and PVA/(DCP/BPR) have been prepared through the casting method. The colorimetric properties of both films changed from violet to pink and from green to yellow with exposures to gamma rays between 0-80 and 0-40 kGy, respectively. The color response was accelerated with chloral hydrate to half of the radiation dose between 0-40 and 0-20 kGy for both systems, respectively. The UV-visible spectrophotometer shows outstanding stability of the prepared dosimetric systems. Relative humidity was studied and the response indicated that both films possess very good stability during irradiation.
Effect of Gamma Radiation on a Mixed Dye Film and Its Possible Use as a Radiation Dosimeter
European Chemical Bulletin
Dyed poly(vinyl alcohol) (PVA) films prepared by a simple technique of casting aqueous PVA solution incorporating a mixture of two dyes namely chlorophenol red (CPR) and Quinaldine Red (QR) on a horizontal glass plate are useful as high dose dosimeter in the dose range 2-30 kGy range. The colour of these films change from deep red to yellow when exposed to gamma radiation. Chloral hydrate was added with different concentrations. The response of the prepared films can be modified either by change of chloral hydrate concentration or ratio of the two dyes. As a result, these films can be used as a dosimeter in two dose ranges. The dosimetric parameters, e.g.; dose response, effect of relative humidity on response as well as pre-and post-irradiation stability of these films have been investigated.
Radiation-induced color bleaching of methyl red in polyvinyl butyral film dosimeter
Radiation Physics and Chemistry, 2011
Radio-chromic film based on polyvinyl butyral (PVB) containing different concentrations of methyl red (MR) dye for 0.125, 0.25 and 0.5 mM has been introduced as high dose dosimeter. The dosimeters were irradiated with gamma ray from 60 Co source at doses from 5 to 150 kGy. UV/vis spectrophotometry was used to investigate the optical density of unirradiated and irradiated films in terms of absorbance at 497 nm. The dose sensitivity of MR-PVB film dosimeter increases strongly with increase of absorbed dose as well as increase of concentrations of MR dye. The effects of irradiation temperature, relative humidity, dose rate and the stability of the response of the films after irradiation were investigated and found that these films could be used as routine dosimeter in industrial radiation processing. The useful dose range of developed MR-PVB film dosimeters is in the range of 5-100 kGy.
Dyed polyvinyl chloride films for use as high-dose routine dosimeters in radiation processing
Radiation Physics and Chemistry, 2004
Characteristics of the polyvinyl chloride (PVC) films containing 0.11 wt% of malachite green oxalate or 6GXsetoglausine and about 100 mm in thickness were studied for use as routine dosimeters in radiation processing. These films show basically color bleaching under irradiation with 60 Co g-rays in a dose range of 5-50 kGy. The sensitivity of the dosimeters and the linearity of dose-response curves are improved by adding 2.5% of chloral hydrate [CCl 3 CH(OH) 2 ] and 0.15% hydroquinone [HOC 6 H 4 OH]. These additions extend the minimum dose limit to 1 kGy covering dosimetry requirements of the quality assurance in radiation processing of food and healthcare products. The dose responses of both dyed PVC films at irradiation temperatures from 20 C to 35 C are constant relative to those at 25 C, and the temperature coefficients for irradiation temperatures from 35 C to 55 C were estimated to be (0.4370.01)%/ C. The dosimeter characteristics are stable within 1% at 25 C before and 60 days after the end of irradiation. r
Dosimetric characterization and spectroscopic study of radiochromic films as natural dye dosimeters
2014
Radiochromic films were prepared with PVA gel matrix and natural dyes (Turmeric, Walnut and Henna) with three concentrations, that is, C1=0.5 g/L, C2=0.25 g/L and C3=0.13 g/L having pH value 4 for acidic samples and 10 for alkaline samples. The thickness of the film was fixed to be 0.05 mm. The behavior of the dyes was studied on the basis of change in specific absorbance with concentration, change in specific absorbance with absorbed dose; effect of pH on specific absorbance, electrical conductivity, molar extinction coefficients, and percentage decoloration. Absorption spectra for un-irradiated and Gamma irradiated films were studied. ʎmax for T= 451 nm, for W=340 nm and for H=320 nm was recorded. Absorbance at each ʎmax was found by using spectrophotometer and specific absorbance was calculated. Response curve for specific absorbance versus concentration showed linear behavior for each dye. Plot of specific absorbance versus dose made the behavior of the dye clear and it was noti...