Build-Up PMMA Plate Effect on Calibration of TLD Reader

The routine monitoring of the occupationally exposed individuals constitutes an integral part of radiation protection program implemented at the Vinca Institute of Nuclear Sciences (INNV). The Individual monitoring service (IMS) at the INNV, accredited according to quality standard EN ISO/IEC 17025, is using Harshaw 6600 Plus automatic reader and thermoluminescent dosimeters (TLD) from two manufacturers (Harshaw, RadPro international GmbH). Working procedures are implemented according to Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, RP 160 (European Commission, 2009). Among general consideration, RP 160 is suggesting that routine calibration of dosimetry system should be performed taking into consideration secondary charged particle equilibrium. As TLD system in use at IMS INNV comprises of TLD reader and of TLD cards, this consideration should be applied in both cases: when the reader and the TLD cards are being calibrated. During reader calibration, secondary charged particle equilibrium can be ensured using build-up PMMA plate of certain thickness placed in front of dosimeters. In this paper, influence of the build-up plate on reader calibration is being analyzed. This influence is observed through changes in reader calibration factor (RCF). RCF values obtained during reader calibration procedure with and without 2 mm thick build-up plate are presented. Exposures of whole body TLDs placed on slab phantom were done with Cs-137 radiation source located at Secondary Standard Dosimetry Laboratory (SSDL) at INNV. TLDs from both manufacturers had 2 detectors for measuring the dose equivalent at the depths of 10 mm and 0.07 mm. TLD reader was calibrated to measure effective dose in terms of Hp(10) and local skin dose in terms of Hp(0.07). RCF values for detectors measuring Hp(10), from both manufacturers, when irradiated without the plate were around 5% higher than RCF values obtained when irradiations were done with the plate. Values of RCFs for detectors measuring Hp(0.07) were around 1% higher when the plate had not been used. As RCF value is inversely proportional to measured dose, reader calibration without build-up plate, in terms of Hp(10), would lead to underestimated dose values. The observed RCF deviation of Hp(0.07) detector is regarded as consequence of exposure conditions uncertainties. In conclusion, if a constant geometry and constant operational conditions of TLDs are achieved, the only part of the TLD system that is not stable for a long time period is the TLD reader. To avoid inaccurate results, RCF should be orderly checked and reader calibration should be done according to widely accepted standards, currently in effect.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Build-Up PMMA Plate Effect on Calibration of TLD Reader

The routine monitoring of the occupationally exposed individuals constitutes an integral part of radiation protection program implemented at the Vinca Institute of Nuclear Sciences (INNV). The Individual monitoring service (IMS) at the INNV, accredited according to quality standard EN ISO/IEC 17025, is using Harshaw 6600 Plus automatic reader and thermoluminescent dosimeters (TLD) from two manufacturers (Harshaw, RadPro international GmbH). Working procedures are implemented according to Technical Recommendations for Monitoring Individuals Occupationally Exposed to External Radiation, RP 160 (European Commission, 2009). Among general consideration, RP 160 is suggesting that routine calibration of dosimetry system should be performed taking into consideration secondary charged particle equilibrium. As TLD system in use at IMS INNV comprises of TLD reader and of TLD cards, this consideration should be applied in both cases: when the reader and the TLD cards are being calibrated. During reader calibration, secondary charged particle equilibrium can be ensured using build-up PMMA plate of certain thickness placed in front of dosimeters. In this paper, influence of the build-up plate on reader calibration is being analyzed. This influence is observed through changes in reader calibration factor (RCF). RCF values obtained during reader calibration procedure with and without 2 mm thick build-up plate are presented. Exposures of whole body TLDs placed on slab phantom were done with Cs-137 radiation source located at Secondary Standard Dosimetry Laboratory (SSDL) at INNV. TLDs from both manufacturers had 2 detectors for measuring the dose equivalent at the depths of 10 mm and 0.07 mm. TLD reader was calibrated to measure effective dose in terms of Hp(10) and local skin dose in terms of Hp(0.07). RCF values for detectors measuring Hp(10), from both manufacturers, when irradiated without the plate were around 5% higher than RCF values obtained when irradiations were done with the plate. Values of RCFs for detectors measuring Hp(0.07) were around 1% higher when the plate had not been used. As RCF value is inversely proportional to measured dose, reader calibration without build-up plate, in terms of Hp(10), would lead to underestimated dose values. The observed RCF deviation of Hp(0.07) detector is regarded as consequence of exposure conditions uncertainties. In conclusion, if a constant geometry and constant operational conditions of TLDs are achieved, the only part of the TLD system that is not stable for a long time period is the TLD reader. To avoid inaccurate results, RCF should be orderly checked and reader calibration should be done according to widely accepted standards, currently in effect.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Review of the thermoluminescent dosimetry method for the environmental dose monitoring

Passive solid state dosimeters, such as thermoluminescence dosimeters, provide integrated measurement of the total dose and are widely used in environmental monitoring programs. The objective of this paper is to provide a comprehensive review on the use of thermoluminescent dosimetry methods for monitoring radiation dose in the environment. The article presents the part of the research results of the project PREPAREDNESS (EMPIR 2016 call for Metrology for Environment joint research project) with a particular objective to harmonize procedures used by dosimetry services, relevant authorities and Institutes across the Europe. To achieve this, different monitoring routines that are based on passive environ mental dosimetry methods are investigated. Differences in performing specific steps such as preheating, reading, annealing, minimizing fading, and others, are analyzed. The investigation was performed by means of qualitative literature review that showed the lack of information about specific steps. The conclusion of this work is that thermoluminescent dosimetry measurement system has to be type-tested even though the testing procedure is complicated. In addition to this, control dosimeters should be introduced, International Organization for Standardization protocols should be followed during calibration, and finally, parameters influencing the measurement uncertainty have to be identified and well understood in order to pro duce ac cu rate dose measurement results

EMPIR project 16ENV04 Preparedness - main goals and research directions

16ENV04 Preparedness je projekat iz poziva EMPIR 2016 za zaštitu životne sredine. Glavni cilj projekta je poboljšanje pripravnosti za nuklearne i radiološke incidente i akcidente, koji bi mogli da se dogode u budušnosti. Pripravnost će biti poboljšana tako što će se izvršiti istraživanja u nekoliko pravaca: upotreba bespilotnih letelica za radiološka merenja, upotreba mobilnih sistema za uzorkovanje vazduha, istraživanje mogućnosti korišćenja radioloških podataka iz nevladinih mreža i korišćenje sistema pasivnih dozimetara za monitoring okoline. Još jedan od načina za poboljšanje pripravnosti je smanjenje mogušnosti bezrazložne panike koja bi mogla da bude izazvana diseminacijom merenja iz nevladinih mreža i drugih izvora, što bi moglo da izazove i smanjenje poverenja u zvanične podatke. U cilju realizacije projekta, od velikog značaja su diseminacija razultata i komunikacija sa svim zainteresovanim stranama.16ENV04 Preparedness is a research project within the EMPIR 2016environment call. The main project goal is to increase the preparedness for nuclear and radiological incidents and accidents that might occur in the future. The preparedness will be increased by pursuing several directions of research: use of unmanned aerial vehicles for radiological measurements, use of transportable air-sampling systems, investigating the crowd sourced radiological data for possible official uses and investigating the use of passive dosimetry systems for ambient monitoring. Another aspect of preparedness is to try to reduce the possibility of unwarranted panic caused by the data disseminated by citizen networks and other sources and to increase confidence in official data. To realize the project goals, communication with stakeholders and dissemination of results are of greatest importance.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Comparison of results of indoor radon concentration obtain by charcoal canisters and track etch detectors

Ugljeni kanisteri se često koriste kao pasivni detektori za određivanje koncentracije 222Rn. Merenja pomoću ugljenih kanistera najčešće traju 2-3 dana, što omogućava brzo dobijanje rezultata, ali je metoda osetljiva na različite uticaje, kao što su visoka vlažnost vazduha, ekstremne temperature, promena koncentracije radona itd. Upravo zbog toga je od velikog značaja poređenje u realnim uslovima ove metode sa drugim metodama, kao što je merenje pomoću trag detektora. Međutim, veoma različita vremena merenja otežavaju ovakvu proceduru. U Institutu za nuklearne nauke „Vinča“ su četiri trag detektora bila postavljena u periodu od 7, odnosno 13 meseci. U istom periodu su kontinuirano menjani ugljeni kanisteri, najčešće dvaput nedeljno. Ovi rezultati su omogućili da se izvrši poređenje metoda, pri čemu su za proračun rezultata za metodu pomoću ugljenih filtera korišćene kalibracione krive i za statičnu atmosferu i za aktivnu atmosferu. Poređenje je pokazalo da ne postoji statistički značajna razlika između metoda bilo koje kalibracione krive da se koriste, s tim što se bolje poklapanje dobija korišćenjem krivih za aktivnu atmosferu.Charcoal canisters are often used as passive detectors for determination of concentration of222Rn. Measurements with charcoal canisters often last 2-3 days, which provides a fast result, but the method is sensitive to many influences, such as high air humidity, extreme temperatures, change of radon concentration etc. This is why the comparison of this method with other methods in realistic conditions is of great importance. However, different measurement times make this comparison complicated. Four track etch detectors were deployed in Vinca Institute of Nuclear Sciences for 7 and 13 months. In the same period, charcoal canisters were continuously changed, usually two times each week. These results allowed comparing the two methods, while the results for charcoal canisters were obtained by using calibration curves for both static and active atmosphere. The comparison showed that there is no statistically significant difference no matter which curves are used. The differences are smaller if the curves for active atmosphere are used.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Comparison of results of indoor radon concentration obtain by charcoal canisters and track etch detectors

Ugljeni kanisteri se često koriste kao pasivni detektori za određivanje koncentracije 222Rn. Merenja pomoću ugljenih kanistera najčešće traju 2-3 dana, što omogućava brzo dobijanje rezultata, ali je metoda osetljiva na različite uticaje, kao što su visoka vlažnost vazduha, ekstremne temperature, promena koncentracije radona itd. Upravo zbog toga je od velikog značaja poređenje u realnim uslovima ove metode sa drugim metodama, kao što je merenje pomoću trag detektora. Međutim, veoma različita vremena merenja otežavaju ovakvu proceduru. U Institutu za nuklearne nauke „Vinča“ su četiri trag detektora bila postavljena u periodu od 7, odnosno 13 meseci. U istom periodu su kontinuirano menjani ugljeni kanisteri, najčešće dvaput nedeljno. Ovi rezultati su omogućili da se izvrši poređenje metoda, pri čemu su za proračun rezultata za metodu pomoću ugljenih filtera korišćene kalibracione krive i za statičnu atmosferu i za aktivnu atmosferu. Poređenje je pokazalo da ne postoji statistički značajna razlika između metoda bilo koje kalibracione krive da se koriste, s tim što se bolje poklapanje dobija korišćenjem krivih za aktivnu atmosferu.Charcoal canisters are often used as passive detectors for determination of concentration of222Rn. Measurements with charcoal canisters often last 2-3 days, which provides a fast result, but the method is sensitive to many influences, such as high air humidity, extreme temperatures, change of radon concentration etc. This is why the comparison of this method with other methods in realistic conditions is of great importance. However, different measurement times make this comparison complicated. Four track etch detectors were deployed in Vinca Institute of Nuclear Sciences for 7 and 13 months. In the same period, charcoal canisters were continuously changed, usually two times each week. These results allowed comparing the two methods, while the results for charcoal canisters were obtained by using calibration curves for both static and active atmosphere. The comparison showed that there is no statistically significant difference no matter which curves are used. The differences are smaller if the curves for active atmosphere are used.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

Harmonisation of dose measurement procedures using passive dosemeters: use of passive H*(10) dosimetry systems in Europe

Jedan od zadataka projekta 16ENV04 Preparedness jeispitivanje pasivnih dozimetrijskih sistema namenjenih za merenje operativne dozimetrijske veličine H*(10). Cilj ovog zadatka je evaluacija i harmonizacija procedura koji koriste laboratorije u Evropi a odnose se na merenje ambijentlnog ekvivalenta doze,a u vezi eventualne primene ovakvih doziemtrisjkih sistema u kontekstu dleovanja u vanrednom događaju.One of the outstanding tasks of the project 16ENV04 Preparedness, is to investigate the use of passive dosemeters aimed for measurement of operational quantityH*(10). The aim of this task is to develop a rationale to harmonize the procedures used by European measuring bodies and authorities, which provide services or fulfil tasks in radiation protection by using passive H*(10) area monitoring systems. Procedures used by European measuring bodies and services for environmental monitoring using passive area dosemeters are investigated, with a goal to investigate the applicability of passive dosimetry systems in the aftermath of a nuclear event.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Sources of uncertainty in classification of radon zones

Evropski savet je doneo direktivu 2013/59/EURATOM (EU-BSS) po kojoj se nalaže državama članicama EU da imaju ustanovljen radonski akcioni plan, što između ostalog podrazumeva i identifikaciju radonskih prioritetnih zona (Radon priority areas), odnosno zona sa različitim nivoom "prioriteta". S obzirom da je neizvodljivo vršiti merenja radona u svakoj kući, potrebno je dizajnirati prospekciju radona kako bi se dobila reprezentativna procena srednje godišnje koncentracije radona u zatvorenim prostorijama na određenoj teritoriji. Nije bitan samo reprezentativan izbor kuća, nego je i nesigurnost merenja i procene srednje godišnje koncentracije potrebno držati što je niže moguće. Nesigurnostn klasifikacije zone određenog prioriteta u nekoj oblasti je stoga kombinacija nesigurnosti pojedinačnog merenja i ekstrapolacije tog merenja na celu oblast. U ovom radu ćemo pokušati da nabrojimo i procenimo izvore nesigurnosti pri klasifikaciji i damo preporuke u cilju smanjenja stepena nesigurnosti. Ovaj rad je urađen u sklopu MetroRadon projekta.The EC has laid down directive 2013/59/EURATOM which represents basic safety standards regarding the radon protection of the European citizens. Within the BSS they oblige countries to establish radon action plans which include identification of Radon Priority Areas (RPA). Since it is not feasible to perform indoor radon measurements in each dwelling, it is necessary to carefully design indoor radon survey in order to get representative estimation of annual average indoor radon concentration of the certain territory. It is not sufficient only to have representative selection of dwellings, but it is important to keep uncertainty of measurement and estimation of annual radon concentration as low as possible. Uncertainty of classification of radon zones is therefore combination of uncertainties coming from a single measurement uncertainty and uncertainty of extrapolation of single or group of measurements to the whole region. In this contribution, we will try to estimate sources of classification uncertainties and to give recommendation in order to reduce level of uncertainty. The research presented in this paper was realized within 16ENV04 MetroRADON project. This project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union‘s Horizon 2020 research and innovation programme.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

MetroRADON - projekat za unapređenje merenja radona u Evropi

Трогодишњи пројекат MetroRADON у оквиру програма EMPIR је фокусиран на следљивост мерења ниске концентрације радона и доприноси стварању координиране метролошке инфраструктуре за мониторинг радона у Европи као и хармонизацији методологија мерења. Циљеви пројекта су да се обезбеди метролошка следљивост калибрације инструмената на ниским концентрацијама са мерном несигурношћу мањом од 5%, да се испита утицај торона и његових потомака на мерење концентрације радона, да се упореде процедуре мерења концентрације радона и брзине ексхалације радона из земљишта у различитим државама у Евопи, да се развију методе идентификацје области са повећаном концентрацијом радона, да се све ове методе валидују и да се олакша коришћење технологије и мерне инфраструктуре коју је развио пројекат од стране крајњих корисника. У овом раду ће бити дат преглед циљева и досадасшњих резултата пројекта.MetroRADON, a three year project based in the EMPIR program, is focused on traceability of low activity radon measurement. It contributes to the creation of the coordinated metrological infrastructure for radon monitoring in Europe, as well as the harmonization of measurement strategy and methodology. The objectives of this project is to secure the metrological traceability of the instrument calibration for the measurement of low activity, with the measurement uncertainty that does not exceed 5%, to investigate the influence of thoron and its progenies on the radon concentration measurements, to compare procedures for measurement of indoor radon concentration and exhalation rate from the soil in different European countries, to develop methods for recognizing the radon priority areas and finally to validate these methods, but at the same time to enable the access of the final users to the measurement technology and infrastructure developed within this project. This paper presents the overview of these objectives and the results achieved in the present time.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Qualitative overview of indoor radon surveys in Europe

The revised European Directive from 2013 regarding basic safety standard oblige EU Member States to establish a national action plan regarding the exposure to radon. At the same time, International Atomic Energy Agency started technical projects in order to assist countries to establish and implement national radon action. As a consequence, in recent years, in numerous countries national radon surveys were conducted and action plans established, which were not performed before. In this paper, a qualitative overview of radon surveys performed in Europe is given with a special attention to the qualitative and conceptual description of surveys, representativeness and QA/QC (quality assurance/quality control). © 201