Characterization of thermoluminescence of chip cards for emergency dosimetry
Introduction
Thermoluminescence (TL) and optically stimulated luminescence (OSL) methods using mobile phone components such as substrate or cover glass, surface mount resistors and integrated circuits have been widely studied for emergency dosimetry (Discher and Woda, 2013; Lee et al., 2015; Sholom and McKeever, 2016). However, these materials are accompanied with labor intensive pretreatment processes, such as sample extraction, washing, and etching, which is a bottleneck for rapid triage in case of radiation accidents or terrorism. Chip card modules are widely used in electronic authorization applications like subscriber identification module (SIM) cards, identity cards, credit cards, and public transit. As such, chip cards are suitable for an individual dose reconstruction in a mass casualty scenario with easy extraction and no pretreatment processes (Göksu, 2003; Mathur et al., 2007; Woda and Spöttl, 2009) and being an item of low replacement cost compared to mobile phones. In a previous study a minimum detectable dose of several tens of mGy was found for chip cards when using OSL, however, the signal loss was over 60% in the first day after irradiation because the recommended protocol did not include a preheat (Woda and Spöttl, 2009). Fading can be significantly reduced for chip card modules with molded encapsulations but the protocol requires a chemical pretreatment with HNO3 (Woda et al., 2012).
TL of chip cards has so far not been used for dose reconstruction due to an intense zero-dose signal, which is the dominant feature in the higher temperature range of the glow curve. Moreover, signal regeneration can be observed when samples are preheated, for instance 100 °C for 10s, possibly caused by the slower reduction rate of the 100 °C TL peak on optical stimulation (Woda and Spöttl, 2009). Nevertheless, TL of chip cards has the potential of enabling better protocols such as an optimized detection window, inferred from TL emission spectra, a lower fading rate when using deeper (higher temperature) traps, and categorization of chip cards based on glow curves. Therefore, in this study, the TL characteristics of different types of chip cards were investigated to determine the limits and potentials of the TL protocols for emergency dosimetry.
Section snippets
Materials and methods
Since types of chip cards that exhibit a radiation response in OSL are limited depending on the manufacture and technology (Bassinet et al., 2010), a good candidate should be identifiable by the manufacturer and have a high radiation response. Therefore, chip cards used in this study were three SIM cards distributed by mobile communication providers in South Korea such as SK Telecom (SKT), Korea Telecom (KT), and LG Telecom (LGT). In addition, three smart Integrated Circuit (IC) cards that can
Results and discussions
TL of chip cards is mainly originated from the silica (SiO2) in the epoxy (Woda and Spöttl, 2009; Woda et al., 2012). In order to confirm the difference in the silica content depending on the chip cards, the EDS analysis was made in Fig. 2. The pictures in the first line in Fig. 2 are SEM images. The second line shows EDS mapping images for silicon and the third line is ones for oxide. Elements other than carbon, oxide, aluminum and silicon were less than 0.1% in weight percent. The width of
Conclusions
Feasibility and limitation of the TL protocol of chip cards for retrospective dosimetry were investigated. The chip cards showed different shape of the intrinsic background signals depending on the manufacturers but can be categorized by emission spectra of RISs. The red emission chip cards were not suitable for a dose estimation due to their unstable signals. On the other hand, a lower and less scattered signal fading was observed in the blue emission chip cards when 100–150 °C interval is
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
The study was mainly carried out under the National Long- & Intermediate-Term Project of Nuclear Energy Development of Ministry of Science and ICT, Republic of Korea (No.2017M2A8A4015255) and is partially conducted in the framework of EPU (Eurasia-Pacific UNINET) network and partially funded by funds of the Federal Ministry of Science, Research and Economy (BMWFW) Austria (project period: 2019).
References (8)
- et al.
Thermoluminescence of glass display from mobile phones for retrospective and accident dosimetry
Radiat. Meas.
(2013) Telephone chip-cards as individual dosemeters
Radiat. Meas.
(2003)On the use of new generation mobile phone (smart phone) for retrospective accident dosimetry
Radiat. Phys. Chem.
(2015)Radiation sensitivity of memory chip module of an ID card
Radiat. Meas.
(2007)
Cited by (10)
OSL at elevated temperature of smart chip cards for retrospective dosimetry
2024, Radiation Physics and ChemistryReflections on the future developments of research in retrospective physical dosimetry
2023, Physics OpenCitation Excerpt :The ubiquity of mobile and electronic devices and especially of cell phones makes their components potentially powerful fortuitous dosimeters: the glass of the touchscreen displays and screen protectors; the aluminium or other metal oxides in the so-called surface mount devices (SMD), which include surface mount resistors (SMR), inductors (IND), and capacitors (CAP); and the material (filler) used to encapsulate microchips within an integrated circuit (IC) package [117]. Radiation sensitive filler material is also used to encapsulate chips found inside credit cards, electronic identity cards, and SIM cards [88,97,118]. Fig. 3 shows a diagram of the assays deriving from electronic devices, which are currently proposed for RD.
Reference dosimetry for inter-laboratory comparison on retrospective dosimetry techniques in realistic field irradiation experiment using <sup>192</sup>Ir
2022, Nuclear Engineering and TechnologyEvaluation of physical retrospective dosimetry methods in a realistic accident scenario: Results of a field test
2021, Radiation MeasurementsCitation Excerpt :If no personal dosimeter is available, mobile phones or other ubiquitous personal belongings, which are carried on or close to the body, can be used as accident dosimeters. Research has been carried out by different groups on e.g. surface mount resistors and inductors on the circuit board of mobile phones (Lee et al., 2017; Bassinet et al., 2017; Ekendahl and Judas, 2012), integrated circuits (Mrozik et al., 2017b; Sholom and McKeever, 2016), display glass (Discher et al., 2020; Kim et al., 2019; Bassinet et al., 2014a; Discher and Woda, 2013), screen protectors (Bassinet and Le Bris, 2020), touchscreen glass (McKeever et al., 2017, 2019; Discher et al., 2016, Fattibene et al., 2014), protective glass on the back of modern smartphones (Sholom et al., 2020), chip cards (Kim et al., 2020; Woda et al., 2012a), dust on the toboacco leaves of cigarettes and other personal objects (Ademola et al., 2017; Bortolin et al., 2011), banknotes (Mrozik et al., 2017a; Sholom and McKeever, 2014) and dental ceramics (Ekendahl and Judas, 2017). Some overviews have been published (Bailiff et al., 2016; ICRU, 2019; Woda et al., 2009).
OSL with chips from US credit cards
2021, Radiation MeasurementsCitation Excerpt :Chips from the SIM cards were tested without any sample preparation; a linear dose-response relationship was observed in the range from 0.5 Gy to 6 Gy; the MDD was about 7 mGy. TL signals from chips have been tested by several research teams (Mathur et al., 2007; Kim et al., 2020; Woda et al., 2012). A strong zero-dose TL signal was observed by Mathur et al. (2007) in identification (ID) cards and then confirmed by Woda et al. (2012) for chip card modules obtained directly from the producer (Infineon).