Effect of UVC radiation on the optical properties of thermally treated CR-39 polymer films: A new approach for the use of CR-39 as an optical dosimeter
Introduction
Polyallyl diglycol carbonate (PADC), commonly known by the brand name CR-39, has been proven to be the most highly sensitive polymeric solid-state nuclear track detector (PSSNTD) (Cartwright et al., 1978). PADC is transparent in the visible spectral region, and has the chemical composition C12H18O7 (density 1.30 g/cm3). PADC can register tracks from charged particles with high resolution. Thus, protons and heavy ions produce latent damage trails, which can be visualized after chemical treatment with a suitable etchant solution. PADC can also register tracks from recoil protons under impact of neutrons or alpha particle emissions from naturally occurring radioactive materials (NORM). It can thus be used in neutron spectrometry and dosimetry (Castillo et al., 2013; Sahoo et al., 2014; Vasconcelos et al., 2019; Saad et al., 2020) and radon dosimetry (Mozzo et al., 1996; Tommasino, 2001; Saad et al., 2013, 2014a, 2018). The properties of polymers can be altered in various ways, such as annealing (Nidhi Gupta et al., 2009; Saad et al., 2012, Saad et al., 2014b); exposure to IR radiation (Prasher and Singh, 2003; Singh and Prasher, 2004; Saad et al., 2019), UV radiation (Saad et al., 2015; Jaleh et al., 2017), gamma-rays (Malek and Chong, 2002; Singh and Prasher, 2004; Saad et al., 2005; Abdul-Kader et al., 2014), alpha particles or heavy ions (Saad et al., 2001; Ishikawa et al., 2008; El Ghazaly and Hassan, 2014); chemical doping (Miyoshi et al., 2015, 2016); or ion implantation (Butt et al., 2014; Chawla et al., 2019).
We have applied ultraviolet/visible (UV/Vis) spectrophotometry to study radiation damage trails for the detection of gamma-rays in CR-39 nuclear track detectors (Saad et al., 2005). Recently, we have used this detector as a gamma dosimeter (Saad et al., 2018, Saad et al., 2020), addressing the question as to whether a CR-39 nuclear track detector might also be used as an optical dosimeter in the UV region following thermal treatment (Khalil, 2019). It has been shown that thermal treatment of CR-39 polymeric detector material, heating it above its glass transition temperature (Tg), can modify its morphology and improve its performance (Nidhi et al., 2009; Gendya, 2019.). Thus, modifications within CR-39 annealed polymeric detectors can have a beneficial effect on their registration and structural properties, and especially their optical properties (Nidhi et al., 2009; Saad et al., 2012, Saad et al., 2014a, Saad et al., 2014b, Saad et al., 2020, Saad et al., 2020). A CR-39 detector consists of repeated units of PADC. PADC consists of two adjacent carbonate ester groups separated by an ether chain. The ether chain can be considered as a radiation-sensitive section, whereas the carbonate ester groups are less radiation-sensitive (Yamauchi et al., 2005a, 2005b, 2008; Ogawara et al., 2020). The structure of PADC is a three-dimensional network consisting of polyallyl chains (Stejny, 1987). Two ethylene units are interposed between the ether and carbonate esters, which can also be regarded as radiation-sensitive. Our UV/Vis studies have indicated that complex compounds are generated as a result of cleavage of the main chain of the polymer material. Clearly, chain rupture increases with increasing gamma-ray dose level for CR-39. A shift in the absorption edge towards higher wavelength indicates a decrease in the band-gap energy for irradiated detectors (Saad et al., 2005, 2018). Our UV/Vis observations suggested that a CR-39 polymer detector could enable determination of a gamma-radiation dose (Saad et al., 2018). Further measurements by FTIR spectroscopy indicated that characteristic functional groups with vibrational bands, such as carbonate ester and ether, in CR-39 polymeric detector material are significantly damaged by different gamma-ray doses ranging from 500 to 3000 kGy (Nwara, 2018). In that study, we delineated distinct mechanisms for the destruction of ether and carbonate groups by gamma-radiation, with ether groups being much more sensitive. Recently, we carried out measurements on thermally treated CR-39 exposed to relatively low gamma-ray doses of up to 1000 kGy, applying UV/Vis spectroscopy (Khalil, 2019; Saad et al., 2020). This study yielded a new approach, introducing a thermal treatment (gamma exposure post-annealing) to obtain a unique dosimeter for gamma-radiation doses ranging from 200 to 1000 kGy.
On the other hand, when PADC polymer (a form of CR-39) is exposed to UVC radiation of sufficient energy (111.28 kcal mol−1) as an ionizing radiation, in the presence of oxygen, a free radical chain is formed as a result of chemical bond cleavage (Adams and Garton, 1993). A mechanism of photo-oxidative degradation (initiation, propagation, termination, and chain branching) ensues. Chemical changes can be attributed to scission of the polymer chains and formation of cross-linkages. Photo-oxidation of CR-39 detectors mainly involves chain scission (Tse et al., 2006; Saad et al., 2015). From the point of view of polymer degradation as a result of UV exposure, we would answer the above question by stating that extension of this approach to UV radiation detection is indeed promising. The aim of this work was to investigate the effects of UV irradiation for different durations on a CR-39 polymeric detector material, with and without thermal treatment, using a UV/Vis spectrophotometer. Finally, we sought to identify the optimum conditions for using CR-39 as a UV radiation-recording polymer with unique resolution.
Section snippets
Materials and methods
CR-39 polymer sheets with a thickness of 750 μm were purchased from Track Analysis Systems Ltd. (TASL), Bristol, UK. The sheets were cut with a laser beam into identical pieces of dimensions 1.5 cm × 2 cm.
Three sets of detectors were prepared for this study. The first set of CR-39 detectors was only exposed to UV radiation from a lamp. The second set of detectors was first annealed in a digital oven and then exposed to UV radiation, i.e. pre-UV thermal annealing (thermal annealing + UV
Measurement of UV/Vis spectra of non-thermally treated and thermally treated UV-radiation exposed CR-39 detector films
Optical absorptions were measured to assess the effect of UV irradiation in non-thermally treated and thermally treated (pre-/post-UV thermal annealing) CR-39 after different exposure times. Fig. 1(a–c) show the UV/Vis spectra of CR-39 polymer films exposed to UV radiation, pre-UV thermal annealing, and post-UV thermal annealing, respectively. In these figures, a shift towards higher wavelengths (red or bathochromic shift) in the absorption spectra of CR-39 polymer films is observed, which
Conclusion
We have introduced a new approach of combined UV and thermal treatments to obtain a unique dosimeter for UV radiation determination over exposure periods of 10–100 h. The obtained results suggest that the extent of UV-induced thermal damage is dose-dependent. Our results imply that this new technique enhances CR-39 detector sensitivity to UVC radiation, allowing high-precision estimation of UV radiation doses. Post-UV thermal annealing treatment has proven to be the most efficient process in
Credit author statement
A.F. Saad: Conceptualization, Methodology, Writing - Reviewing, Editing; Ebrahim M. Sedqy: Data analysis, Data curate, Investigation, Writing - Original draft preparation; Rania M. Ahmed: Investigation, Writing - Original draft preparation.
Declaration of competing interest
No conflict.
References (48)
- et al.
Modified the optical and electrical properties of CR-39 by gamma ray irradiation
J. Radiation Res. and Appl. Sc.
(2014) - et al.
Surface modification of bisphenoi-Apolycarbonate by far-UV radiation. Part I: in vacuum
Polym. Degrad. Stabil.
(1993) - et al.
Structural and optical properties of CR-39 polymer implanted with laser produced plasma ions of iron
Physica B
(2014) - et al.
A nuclear-track-recording polymer of unique sensitivity and resolution
Nucl. Instrum. Methods
(1978) - et al.
Fast neutron dosimetry using CR-39 track detectors with polyethylene as radiator
Radiat. Meas.
(2013) - et al.
Surface characteristics of nitrogen ion implanted CR-39 polymer: RBS studies
Vacuum
(2019) - et al.
Spectroscopic studies on alpha particle-irradiated PADC (CR-39 detector)
Results in Physics
(2014) - et al.
Investigating wettability and optical properties of PADC polymer irradiated by low energy Ar ions
Surf. Coating. Technol.
(2014) - et al.
Surface properties of UV irradiated CR-39 polymer before and after chemical etching and registration of fingerprints on CR-39
Radiat. Meas.
(2017) - et al.
Generation of CO2 in γ-ray-irradiated CR-39 plastic
Radiat. Meas.
(2002)
Silica-nanocapsule-doped CR-39 for fluorescence detection of X-rays
Physics Procedia
Optical property of CR-39 synthesized by doping with methylviologen encapsulated SiO2 nanocapsules as a solid-state X-ray plate detector
Opt. Mater.
a-spectroscopy on CR-39 track detectors for the dosimetery of radon daughters
Environ. Int.
Detection of alpha and 7Li particles from 10B(n, α)7Li reactions using a combination of CR-39 nuclear track detector and potassium hydroxideethanol-water solution in accelerator-based neutron fields
Nucl. Instrum. Methods Phys. Res. B
The effect of infrared radiation on etching characteristics of CR-39 plastic track recorder
Radiation Measurements
Study of optical band gap, carbonaceous clusters and structuring in CR-39 and PET polymers irradiated by 100 MeV O7+ ions
Physica B
FT-IR spectroscopy of carbon dioxide in CR-39 and SR-90 track detectors irradiated with ions and gamma-rays at different energies and influences
Radiat. Meas.
Radiation-induced modifications on spectroscopic and thermal properties of CR-39 and SR-90 nuclear track detectors
Radiat. Meas.
Modifications of the registration properties of charged particles in a CR-39 polymeric track detector induced by thermal annealing
Nucl. Instrum. Methods Phys. Res. B
Radon exhalation from Libyan soil samples measured with the SSNTD technique
Appl. Radiat. Isot.
Changes in the thermal properties of PADC film-based nuclear track detectors produced by high doses of γ-radiation
Nucl. Instrum. Methods Phys. Res. B
Study of the optical properties of etched alpha tracks in annealed and non-annealed CR-39 polymeric detectors
Radiat. Phys. Chem.
Ultraviolet radiation-induced modifications of the optical and registration properties of a CR-39 nuclear track detector
Nucl. Instrum. Methods Phys. Res. B
Modifications in the optical and thermal properties of a CR-39 polymeric detector induced by high doses of γ-radiation
Radiat. Phys. Chem.
Cited by (12)
Studies of chemical bonds loss and optical modifications of CR-39 caused by gamma rays
2024, Radiation Physics and ChemistryThe irradiation impacts of high gamma doses on optical features and degradation of Makrofol DE 1-1
2023, Ceramics InternationalCitation Excerpt :Ionizing radiations including gamma-rays, X-rays, accelerated electrons, and ion beams, cause the development of extremely reactive intermediate products such as excited states, ions, free radicals and create new bonds within polymers. Further, the ionizing radiation reactions with polymers create oxidized products, main chain scission (degradation), cross-linking, and changes in the properties of polymers such as optical, thermal and electrical properties [12–20]. The impact of different types of radiation on Makrofol polycarbonate properties has been studied using a variety of radiations by many researchers [2,4,5,11,14–19].
Extended dose response of <sup>10</sup>B+CR-39 for thermal neutrons using spectrophotometric techniques
2022, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated EquipmentInfluence of irradiation of CR-39 with α-particles on the optical dispersion parameters: Role of chemical etching to develop nuclear tracks
2022, Radiation Physics and ChemistryThe Annealing Impact on Properties of CN- 85 Polymer NTD
2021, Applied Radiation and IsotopesRole of energy loss-range profile of heavy ions in tailoring the optical properties of polycarbonate
2021, Optical MaterialsCitation Excerpt :Such a decline in Eopt after ion implantation may be attributed to the formation of highly crosslinked carbonised structure, rich in charge carriers, within the implanted layer of polycarbonate [1,2,14–20]. The tailoring of Eopt, transmittance and reflectivity of optically transparent PC through ion implantation may be of practical interest into a variety of optoelectronic applications [1,2,10–23]. From the detailed analysis of Figs. 1 and 2 and Table 1, the changes in optical properties of Polycarbonate have been found to be more pronounced in the case of N+ ions compared to Ar+ and Kr+ ions having the same energy and at the same ion fluence.