Modeling alpha particle-induced radioluminescence using GEANT4

Optical detection of alpha particle emitters in the environment by air radioluminescence is a new technology that enables sensing a radiological threat at safe distances, without putting personnel at risk or contaminating equipment. Radioluminescence detection systems need to be fine-tuned to efficiently capture a substantial number of photons while minimizing the contribution from ambient ultraviolet light. The accurate simulation of radioluminescence, in conjunction with ray tracing, facilitates the design and optimization of such detection systems. In this work, an application within the Geant4 framework has been developed to simulate radioluminescence photons emitted in the vicinity of accelerated alpha particles and at the surface of alpha radioactive samples. The application relies on existing scintillation physics implemented in Geant4 classes such as G4OpticalPhysics and G4Scintillation, which are used to simulate radioluminescence photons as scintillations produced during the passage of alpha particles through air. The application computes the ultraviolet image of alpha particles accelerated at energies of 5.1 MeV and 8.3 MeV, as well as an extended alpha source. The application enables optimization of experimental setups for various scenarios, such as radiological emergency management, radiological crime scene investigations, or decommissioning of nuclear facilities, thus minimizing the use of costly resources and exposure to radiation.Comment: 12 pages, 3 figures, 1 tabl

Recent Deforestation Pattern Changes (2000-2017) in the Central Carpathians:A Gray-Level Co-Occurrence Matrix and Fractal Analysis Approach

The paper explores the distribution of tree cover and deforested areas in the Central Carpathians in the central-east part of Romania, in the context of the anthropogenic forest disturbances and sustainable forest management. The study aims to evaluate the spatiotemporal changes in deforested areas due to human pressure in the Carpathian Mountains, a sensitive biodiverse European ecosystem. We used an analysis of satellite imagery with Landsat-7 Enhanced Thematic Mapper Plus (Landsat-7 ETM+) from the University of Maryland (UMD) Global Forest Change (GFC) dataset. The workflow started with the determination of tree cover and deforested areas from 2000–2017, with an overall accuracy of 97%. For the monitoring of forest dynamics, a Gray-Level Co-occurrence Matrix analysis (Entropy) and fractal analysis (Fractal Fragmentation-Compaction Index and Tug-of-War Lacunarity) were utilized. The increased fragmentation of tree cover (annually 2000–2017) was demonstrated by the highest values of the Fractal Fragmentation-Compaction Index, a measure of the degree of disorder (Entropy) and heterogeneity (Lacunarity). The principal outcome of the research reveals the dynamics of disturbance of tree cover and deforested areas expressed by the textural and fractal analysis. The results obtained can be used in the future development and adaptation of forestry management policies to ensure sustainable management of exploited forest areas

New metrology for radon at the environmental level

International audienc

An innovative idea for developing a new gamma-ray dosimetry system based on optical colorimetry techniques

Obtaining knowledge of the absorbed dose up-taken by a certain material when it is exposed to a specific ionizing radiation field is a very important task. Even though there are a plenitude of methods for determining the absorbed dose, each one has its own strong points and also drawbacks. In this article, an innovative idea for the development of a new gamma-ray dosimetry system is proposed. The method described in this article is based on optical colorimetry techniques. A color standard is fixed to the back of a BK-7 glass plate and then placed in a point in space where the absorbed dose needs to be determined. Gamma-ray–induced defects (color centers) in the glass plate start occurring, leading to a degree of saturation of the standard color, which is proportional, on a certain interval, to the absorbed dose. After the exposure, a high-quality digital image of the sample is taken, which is then processed (MATLAB), and its equivalent IRGB intensity value is determined. After a prior corroboration between various well-known absorbed dose values and their corresponding IRGB values, a calibration function is obtained. By using this calibration function, an ''unknown'' up-taken dose value can be determined. Keywords: Absorbed Dose, Colorimetry, Color Standards, Gamma Rays, MATLAB, RG

Intercomparison of Radon Flux Monitors at Low and at High Radium Content Areas under Field Conditions

International audienceInterlaboratory exercises are a good tool to compare the response of different systems to the same quantity and to identify possible inconsistencies between them. One of the main goals of the EMPIR 19ENV01 traceRadon project is to harmonize radon flux measurements based on different systems and methodologies. In the framework of the traceRadon Project, two radon flux intercomparison campaigns were carried out in October 2021 at high and at low radon source areas. Four institutions participated in the field intercomparison exercises with their own systems. Every system was based on a specific radon monitor (diffusion or pump mode) and an accumulation chamber (with manual or automatic opening). Radon fluxes were calculated by each participant using both exponential and linear fittings of the radon activity concentration measured over time within the accumulation chambers. The results of this study show mainly: (i) the exponential approach is not advisable due to the variability of the radon flux and the leakage of the systems during long-time measurements; (ii) the linear approach should be applied to minimize the measurement period in agreement with the time response and sensitivity of the monitors; (iii) radon flux measured at high radon source areas (radium content of about 800 Bq kg−1) risks being underestimated because of the influence of advective effects; (iv) radon flux measured at low radon source areas (radium content of about 30 Bq kg−1) may present large uncertainties if sensitive radon monitors with pump mode are not used

European Metrology Network for Radiation Protection: Education and Training activities

Purpose: The European regulation for protection against exposure to ionizing radiation is essentially laid down in the Council Directive 2013/59/EURATOM. The practical implementation of the European basic safety standards has become more complex due to the lack of consideration of the metrological implications and the adaptation to new technological developments. To overcome such a difficulty, a European Metrology Network for Radiation Protection (EMN RP) was stablished in September 2021 to act as a focal point between the metrology communities and the relevant radiation protection stakeholders, including regulators, standardization bodies, manufacturers, users of radiation sources and international organizations. Materials and Methods: In the work package knowledge transfer, the supporting project 19NET03 supportBSS, together with its EMN RP partners, EURADOS and the German Federal Office for Radiation Protection (BfS), organizes an international training course on dosimetry and emergency preparedness in collaboration with the UK Health and Safety Agency (UK HSA) and the Greek Atomic Energy Commission (EEAE) as local host. The course will be held at EEAE in Athens, Greece, from 18 to 21 September 2023. Webpage: http://www.ptb.de/tceurados-wg2-2023 Results: The aim of this course is to provide the theoretical background of dealing with emergencies and to enhance it with practical measurement exercises. The course consists of three days of lectures and discussions combined with one day of practical exercises in small groups of five people. Lecturers from different European institutes will present various topics from different perspectives. Conclusions: This paper evaluates the course content and the feedback from the participants. This course can serve as a basis for further courses that can then be offered by appropriate platforms.ERPW 2023 - European Radiation Protection Week, 9-13th October 2023, Dublin, Irelan

Antibiotic Prescription and In-Hospital Mortality in COVID-19: A Prospective Multicentre Cohort Study

Background: Since the beginning of the COVID-19 pandemic, empiric antibiotics (ATBs) have been prescribed on a large scale in both in- and outpatients. We aimed to assess the impact of antibiotic treatment on the outcomes of hospitalised patients with moderate and severe coronavirus disease 2019 (COVID-19). Methods: We conducted a prospective multicentre cohort study in six clinical hospitals, between January 2021 and May 2021. Results: We included 553 hospitalised COVID-19 patients, of whom 58% (311/553) were prescribed antibiotics, while bacteriological tests were performed in 57% (178/311) of them. Death was the outcome in 48 patients—39 from the ATBs group and 9 from the non-ATBs group. The patients who received antibiotics during hospitalisation had a higher mortality (RR = 3.37, CI 95%: 1.7–6.8), and this association was stronger in the subgroup of patients without reasons for antimicrobial treatment (RR = 6.1, CI 95%: 1.9–19.1), while in the subgroup with reasons for antimicrobial therapy the association was not statistically significant (OR = 2.33, CI 95%: 0.76–7.17). After adjusting for the confounders, receiving antibiotics remained associated with a higher mortality only in the subgroup of patients without criteria for antibiotic prescription (OR = 10.3, CI 95%: 2–52). Conclusions: In our study, antibiotic treatment did not decrease the risk of death in the patients with mild and severe COVID-19, but was associated with a higher risk of death in the subgroup of patients without reasons for it

Novel optical technologies for emergency preparedness and response : Mapping contaminations with alpha-emitting radionuclides

Radiological emergencies involving an accidental or deliberate dispersion of alpha-emitting radionuclides in the environment can cause significant damage to humans and societies in general. Currently, there is a metrology gap in managing such emergencies due to the lack of detectors that can measure alpha particles at distances greater than their range in air: most conventional alpha detectors are only effective when placed just a few centimeters above the contaminated area. This paper presents the development and testing of lens based optical detection systems that utilize alpha particle-induced ultraviolet (UV) luminescence of air, known as alpha radioluminescence. Telescopes based on fused silica and Poly(methyl 2-methylpropenoate) (PMMA) Fresnel lenses were investigated for their usability in facilitating emergency management related to alpha-emitting radionuclides. Careful matching of the diameter and focal length of the receiving optics, the response of the photocathode, and the passband of the filter allows detection sensitivities as high as 34s−1MBq−1 at 2m source-to-detector distance and background count rate of about 3s−1 in the UV-C spectral region, and suppression of daylight background count rate down to 16s−1. By flushing the source with nitrogen (N2) containing trace amounts of nitric oxide (NO), a groundbreaking sensitivity of 1.3×105s−1MBq−1 has been achieved, allowing detection limits as low as 100Bq with room lighting on, and 70Bq in a dark environment. In the UV-A spectral region, a detection limit of 4kBq could be achieved in a dark environment. These optical detection systems are aimed to facilitate a rapid, coordinated, and effective response in emergency situations involving the release of alpha-emitting radionuclides by mounting them on a tripod or an unmanned aerial device (UAV).publishedVersionPeer reviewe

Metrology for radiation protection: a new European network in the foundation phase

International audienceEuropean Metrology Networks are organized under the umbrella of EURAMET in order to improve Europe’s metrology capabilities based on the high-quality research and metrology service. One of the proposed European Metrology Networks is currently prepared by the EMPIR 19NET03 supportBSS Joint Network Project to address the needs in metrology for radiation protection and radiation protection regulation. The new network EMN for Radiation Protection (short name: RadiationProtect) that was approved by EURAMET in the General Assembly 2021 aims to improve communication between regulatory bodies, metrology institutes, and their stakeholders, promote smart specialization of calibration laboratories, establish a knowledge sharing program, and create roadmaps for future research priorities in the field of radiation protection metrology