Robert Bernat

EURAMET EMPIR 19NET03 supportBSS project entitled Support for a European Metrology Network (EMN) on reliable radiation protection regulation, started in June 2020 and completed in May 2024. One of the tasks of the supportBSS project was the preparation of a Strategic Research Agenda (SRA) based on the identified metrology needs to support the European legislation and regulation in Radiation Protection, and of two Roadmaps for metrology services and capabilities, one under the European Council Directive 2013/59/EURATOM and the other under the EURATOM Treaty. The preparation of the SRA began with a comprehensive literature review including the analysis of the SRAs from the MEENAS Radiation Protection platforms and of strategic documents from other relevant organizations such as IAEA, BIPM-CCRI, HERCA, EURAMET, among others. Information was also collected from the stakeholders at different stages of the project, through organized workshops and a targeted questionnaire, which included specific sections for metrology laboratories and for stakeholders from the different fields of activity. This paper presents the first SRA and Roadmaps developed as key outputs of the supportBSS project, presented to EURAMET as deliverables 4 and 5 at the closure of the project. Taking into account the ongoing technological developments in the field, as well as the fact that EURAMET may use the information collected at its own discretion, it is anticipated the European Metrology Network for Radiation Protection will need to periodically revise and update these documents in the near future.

Individual monitoring of external radiation is an activity usually regulated by national regulatory bodies in most countries. Regulations generally contain technical requirements to be met by the individual monitoring services (IMS), in order to ensure that the measurements are correct and therefore the dosimetry results are reliable. In some countries, the requirements include or even consist of the accreditation of the service according to the standard ISO/IEC 17025: ‘General requirements for the competence of testing and calibration laboratories.’ It is a fact that accreditation is a growing trend among European IMS as a way to guarantee confidence in their technical competence. The acceptance of the dosimetry results between countries and their indentation in the respective National Dose Registries is facilitated if laboratories conform to the ISO/IEC 17025 standard. In the framework of the activities of EURADOS (European Radiation Dosimetry Group) working group 2 ‘Harmonization of Individual Monitoring in Europe’ and attending to the concern of many European IMS in the process of accreditation, a guide has been prepared. The purpose was to assist and encourage IMS to apply for accreditation and to share the authors’ own experience with the process. The guide intends to be a practical reference for IMS on how to interpret and implement the ISO/IEC 17025 requirements to the specific activity of a personal dosimetry service for external radiation, emphasizing those aspects of special interest. It includes examples from dosimetry laboratories already accredited. The major novelties from a new edition of ISO/IEC 17025: 2017 are also identified in the guide. Finally, the guide aims to assist the auditing process, giving examples of auditor’s questions and how to show evidence of compliance. The main findings are presented.

We report on the effects of large-area 4H-SiC Schottky barrier diodes on the radiation response to ionizing particles. Two different diode areas were compared: 1 mm × 1 mm and 5 mm × 5 mm. ⁶LiF and ¹⁰B₄C films, which were placed on top of the diodes, were used as thermal neutron converters. We achieved a thermal neutron efficiency of 5.02% with a ⁶LiF thermal neutron converter, which is one of the highest efficiencies reported to date. In addition, a temperature-dependent radiation response to alpha particles was presented. Neutron irradiations were performed in a JSI TRIGA dry chamber and an Am-241 wide-area alpha source was used for testing the alpha response of the 4H-SiC Schottky barrier diodes.

We report on a bistable defect known as M-center, here introduced in n-type 4H-SiC by 2 MeV He ion implantation. Deep levels of the M-center are investigated by means of junction spectroscopy techniques, namely, deep level transient spectroscopy (DLTS) and isothermal DLTS. In addition to previously reported three deep levels arising from the M-center (labeled as M₁, M₂, and M₃), we provide direct evidence on the existence of a fourth transition (labeled as M₄) with an activation energy of 0.86 eV. Activation energies and apparent capture cross sections for all four metastable defects are determined. From first-principles calculations, it is shown that the observed features of the M-center, including the charge state character, transition levels, bi-stability dynamics, and annealing, are all accounted for by a carbon self-interstitial.

In this work, we present the improved efficiency of 4H-SiC Schottky barrier diodes-based detectors equipped with the thermal neutron converters. This is achieved by optimizing the thermal neutron converter thicknesses. Simulations of the optimal thickness of thermal neutron converters have been performed using two Monte Carlo codes (Monte Carlo N–Particle Transport Code and Stopping and Range of Ions in Matter). We have used ⁶LiF and ¹⁰B₄C for the thermal neutron converter material. We have achieved the thermal neutron efficiency of 4.67% and 2.24% with ⁶LiF and ¹⁰B₄C thermal neutron converters, respectively.

More than 23 million workers worldwide are exposed occupationally to ionizing radiation in the workplace and all people in the world are exposed to environmental radiation. Due to developments in healthcare and changes in living conditions, radiation exposure from artificial and natural sources has been increasing for years. Accurate measurement of radiation dose is key to ensuring safety, but there are two challenges to address. First, new standards and reference fields are needed due to the rapid developments in medical imaging, radiotherapy and industrial applications. Second, communication channels are needed to ensure that information on best practice in measurements reaches the people concerned effectively and quickly.It is therefore necessary to provide access to identified problems and solutions on an international level. A European Metrology Network (EMN) under the roof of EURAMET is in the foundation phase prepared by the project supportBSS[1]. This project will prepare this future EMN by addressing this issue through the identification of stakeholder research needs and implementing a long-term ongoing dialogue between them and the metrology community. The EMN will serve as a single point of contact to address all metrological needs related to radiation protection and will relate to all environment processes in which ionising radiation and radionuclides are involved.A Strategic Research Agenda and two roadmaps are under development, covering the metrology needs of both the Euratom Treaty and the EU Council Directive 2013/59/EURATOM (laying down basic safety standards for protection against the dangers arising from exposure to ionizing radiation). Furthermore, long-term knowledge-sharing and capacity building will be supported and a proposal for a joint and sustainable European metrology infrastructure is in the development. This will significantly strengthen radiation protection metrology and support radiation protection measures. The final goal of the network project is a harmonised, sustainable, coordinated, and smart specialised infrastructure to underpin the needs expressed in the European regulation for radiation protection. [1] 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. 19NET03 supportBSS denotes the EMPIR project reference.  

We report the response of newly designed 4H-SiC Schottky barrier diode (SBD) detector prototype to alpha and gamma radiation. We studied detectors of three different active area sizes (1 × 1, 2 × 2 and 3 × 3 mm²), while all detectors had the same 4H-SiC epi-layer thickness of approximately µm, sufficient to stop alpha particles up to 6.8 MeV, which have been used in this study. The detector response to the various alpha emitters in the 3.27 MeV to 8.79 MeV energy range clearly demonstrates the excellent linear response to alpha emissions of the detectors with the increasing active area. The detector response in gamma radiation field of Co-60 and Cs-137 sources showed a linear response to air kerma and to different air kerma rates as well, up to 4.49 Gy/h. The detector response is not in saturation for the dose rates lower than 15.3 mGy/min and that its measuring range for gamma radiation with energies of 662 keV, 1.17 MeV and 1.33 MeV is from 0.5 mGy/h–917 mGy/h. No changes to electrical properties of pristine and tested 4H-SiC SBD detectors, supported by a negligible change in carbon vacancy defect density and no creation of other deep levels, demonstrates the radiation hardness of these 4H-SiC detectors.

Individual hand monitoring for workers who manipulate unsealed radioactive sources in nuclear medicine is a necessity and the results can serve as the base for optimization processes. We performed an analysis of individual hand doses for medical staff preparing and applying radiopharmaceuticals (99mTc, 123I, 201Tl, 131I, or 125I) in three Croatian clinical hospitals, for a period of one year since extremity monitoring became legally mandatory in Croatia. The majority of annual hand doses for workers were below or slightly above 150 mSv per year with only a few workers exceeding the annual dose limit of 500 mSv. The analysis confirmed that the radiation protection expert's role in an individual monitoring programme and personal dosimetry is crucial in order to achieve the optimal radiation protection of workers.