Study on the uncertainty of passive area dosimetry systems for environmental radiation monitoring in the framework of the EMPIR "Preparedness" project

Abstract One of the objectives of the EMPIR project 16ENV04 "Preparedness" is the harmonization of methodologies for the measurement of doses with passive dosimetry systems for environmental radiation monitoring in the aftermath of a nuclear or radiological event. In such cases, measurements are often performed at low radiation dose rates, close to the detection limit of the passive systems. The parameters which may affect the dosimetric results of a passive dosimetry system are analyzed and four laboratories quantitatively evaluate the uncertainties of their passive dosimetry systems. Typical uncertainties of five dosimetric systems in four European countries are compared and the main sources of uncertainty are analyzed using the results of a questionnaire compiled for this specific purpose. To compute the characteristic limits of a passive dosimetry system according to standard ISO 11929, the study of the uncertainty of the system is the first step. In this work the uncertainty budget as well as the characteristic limits (decision thresholds and detection limits) are evaluated and the limitations and strengths of a complete analysis of all parameters are presented

Testing of low-cost dosimeters used in non-governmental networks within 16ENV04 Preparedness project

Recent advances in microelectronics and information technologies, along with the expansion of citizen science, have changed the way measurements are done in many scientific fields, including ionising radiation dosimetry. Many low cost user-friendly instruments are now available for purchase over the internet. Most of the instruments can be connected with applications for real time measurements, and some of them provide possibilities for real time upload to the specialized public websites. Low cost and low requirements for technical knowledge allow many laymen to perform measurements, and results can be easily disseminated via social networks and media outlets. These results are often not verified and low-cost instruments are usually not type tested, so there is a significant possibility for such results to cause misinformation of public or even unwarranted panic. Research on non-governmental dosimetry networks has been conducted within the Work Package 3 of 16ENV04 Preparedness, scientific project within the European Metrology Programme for Innovation and Research (EMPIR). The research has identified non-governmental networks with the densest networks and most active websites, because such networks have the largest potential impact on the public. Measuring instruments used in non-governmental networks (MINN) have been identified, and a total of 16 types of MINNs have been sourced, commissioned and tested in dosimetry laboratories of Vinca Institute of Nuclear Sciences (VINS), Serbia, PhysikalischTechnische Bundesanstalt (PTB), Germany, National Physics Laboratory (NPL), United Kingdom and Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). The tests included linearity and energy dependence of the response in photon fields generated at each institute, determination of inherent background, response to cosmic radiation, response to small changes of background radiation and tests of dependence of the response on climatic conditions – humidity and temperature, at PTB facilities. The research has shown that most of the MINNs are based on non-compensated Geiger Mueller tubes, with the consequence that the energy dependence does not conform to the requirements of relevant standards. Dead time correction is not performed in most low-cost instruments, but the linearity is within ±15 % in the dose rate range of interest for environmental monitoring. Response to small changes in background dose rate is dependent not only on the radiation detector, but also on the software and the mode of operation selected by user. In field tests, most dosimeters were sensitive to small changes in background radiation.VIII International Conference on Radiation in Various Fields of Research : RAD 2020 : book of abstracts; Virtual Conferenc

Testing of the measuring instruments in non-governmental networks for the purpose of environmental monitoring of ionising radiation

Non-governmental networks for environmental monitoring employ a wide range of radiation protection instruments from different manufacturers, which provide the public with often unreliable dosimetric data. These Measuring Instruments in Non-governmental Networks (MINN) are mostly based on Geiger-Muller tube gas detectors, which represent low-cost easily operated instruments. An extensive testing of these devices was performed in order to validate the data acquired with MINN within the 16ENV04 Preparedness EMPIR project. In total, 16 different dosemter types were selected, with a sample size of four dosemeters per dosemeter type. Performance testing included the energy dependence and the linearity tests of the dosemeter response. Additionally, during the Researcher Mobility Grant associated with the 16ENV04 project, two Geiger-Muller based dosemeter types, with a sample size of two dosemeters per type were included in the testing. These instruments were subjected to the angular dependence testing in both horizontal and vertical planes, besides the energy dependence and linearity tests in the reference Cs-137 field at Physikalisch-Technische Bundesanstalt (PTB). For all the dosemeter types, inherent background, response to secondary cosmic radiation and the response to small changes of dose rate were determined at the metrological facilities of PTB. The sensitivity of the measuring instruments used in non-governmental networks to small variations of the ambient dose equivalent rate was examined by exposing the dosemeters to low dose rate Cs-137, Co-60 and Ra-226 radiation sources, in order to estimate the effect of environmental radioactive contamination with artificially produced radionuclides. For the comparison purposes, besides the measuring instruments used in non-governmental networks, a previously characterized CdZnTe-based spectrodosemeter was irradiated with the aforementioned radiation fields. The measured values were compared with a reference Reuter-Stokes ionisation chamber used for low-dose rate level measurements.RAP 2020 : International conference on radiation applications; Book of abstracts; Virtual conference, 202

Investigation into the performance of dose rate measurement instruments used in non-governmental networks

In the aftermath of a nuclear or radiological accident, an extended mapping of reliable dose rate values is of key importance for any governmental decision and countermeasures. Presently, numerous dosimetry network stations, operated by the national governments of the member states in Europe, provide such dose rate data on an hourly basis. Nevertheless, there are large areas in Europe that are not covered at all by these early warning networks and other areas that show only a low density of governmental network stations. Hence, there may be a significant lack of information in case of a nuclear or radiological emergency. As a consequence of the Fukushima Daiichi nuclear power plant accidents in 2011, a number of non-governmental radiation monitoring networks (NRMN) appeared on the internet, providing dose rate data based on stationary as well as on mobile measurements of ionizing radiation by laypersons. Especially the mobile detectors are able to cover large areas in short time. Therefore, it is of considerable importance to investigate the feasibility of using dose rate data from non-governmental networks as a complementary input to the European Radiological Data Exchange Platform (EURDEP). Within the European Metrology Program for Innovation and Research (EMPIR), the project 16ENV04 “Preparedness” has studied the metrological relevance of such non-governmental dose rate data (also called crowd-sourced radiological monitoring) in the most comprehensive way so far. Sixteen different dose rate detector systems (in general 4 of each type, plus 2 types with 2 detectors, i.e. 68 detectors in total) used in NRMN have been investigated for the reliability of their data and the corresponding networks, and their data provision to the public were analyzed. The most relevant performance parameters of dosimetry systems (detector's inherent background, energy dependence and linearity of the response as well as the response to secondary cosmic radiation, the sensitivity to small increases of the dose rate and finally the stability of the detector's indication at various climatic conditions - temperature and humidity) have been investigated for fourteen representative types of non-governmental dose rate measuring instruments. Results of this comprehensive performance study of the simple, light-weighted and cheap dose rate meters used in NRMN, and conclusions on the feasibility of using their data for governmental monitoring in case of a nuclear or radiological emergency are presented. © 2021 The Author

A Path to the Stars: The Evolution of the Species

During the last years, a number of telescopes have been dedicated to the followup of the GRBs. But after the Swift launch, the average observed intensity of the GRBs showed to be lower than thought before. Our experience with the robotic 60 cm REM telescope confirmed this evidence, with a large number oflostGRBs. Then, we proposed to study the feasibility of a 4 m fast pointing class telescope, equipped with a multichannel imagers, from Visible to Near Infrared. In this paper, we present the main result of the feasibility study we performed so far

The Necrotic Signal Induced by Mycophenolic Acid Overcomes Apoptosis-Resistance in Tumor Cells

The amount of inosine monophosphate dehydrogenase (IMPDH), a pivotal enzyme for the biosynthesis of the guanosine tri-phosphate (GTP), is frequently increased in tumor cells. The anti-viral agent ribavirin and the immunosuppressant mycophenolic acid (MPA) are potent inhibitors of IMPDH. We recently showed that IMPDH inhibition led to a necrotic signal requiring the activation of Cdc42.Herein, we strengthened the essential role played by this small GTPase in the necrotic signal by silencing Cdc42 and by the ectopic expression of a constitutive active mutant of Cdc42. Since resistance to apoptosis is an essential step for the tumorigenesis process, we next examined the effect of the MPA–mediated necrotic signal on different tumor cells demonstrating various mechanisms of resistance to apoptosis (Bcl2-, HSP70-, Lyn-, BCR-ABL–overexpressing cells). All tested cells remained sensitive to MPA–mediated necrotic signal. Furthermore, inhibition of IMPDH activity in Chronic Lymphocytic Leukemia cells was significantly more efficient at eliminating malignant cells than apoptotic inducers.These findings indicate that necrosis and apoptosis are split signals that share few if any common hub of signaling. In addition, the necrotic signaling pathway induced by depletion of the cellular amount of GTP/GDP would be of great interest to eliminate apoptotic-resistant tumor cells

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Environmental Gamma Dose Rate Monitoring and Radon Correlations: Evidence and Potential Applications

Gamma emitting radionuclides naturally present in the Earth’s crust and the radon exhaled by soil in the atmosphere with its short-lived progeny are two of the main contributors to the environmental gamma dose rate that typically characterizes an outdoor measurement site. The present work aims to investigate variations in the environmental dose-rate time series originated by different natural phenomena, such as weather and seismic events, which can modify the radon concentration in the air. The data analyzed here were acquired over a five-year period using a Reuter–Stokes high-pressure ionization chamber placed in the ENEA Casaccia Research Center (Rome, Italy), from November 2013 to December 2018. The detector was set to take a single measurement of the equivalent ambient dose H*(10) every 15 min, thereby collecting more than 184,000 values over the five-year period under consideration. The detector’s sensitivity to the short-lived radon progeny was verified in a preparatory study performed by means of simultaneous radon flux measurement on field. Variations induced by meteorological events as well as variations potentially induced by seismic events were investigated by implementing different data analysis techniques. In the latter case, a retrospective preliminary study was conducted, applying the ARFIMA class of models in order to test the method’s potential. The analysis techniques, results and potential applications are presented and discussed in this article

Environmental Gamma Dose Rate Monitoring and Radon Correlations: Evidence and Potential Applications

Gamma emitting radionuclides naturally present in the Earth&rsquo;s crust and the radon exhaled by soil in the atmosphere with its short-lived progeny are two of the main contributors to the environmental gamma dose rate that typically characterizes an outdoor measurement site. The present work aims to investigate variations in the environmental dose-rate time series originated by different natural phenomena, such as weather and seismic events, which can modify the radon concentration in the air. The data analyzed here were acquired over a five-year period using a Reuter&ndash;Stokes high-pressure ionization chamber placed in the ENEA Casaccia Research Center (Rome, Italy), from November 2013 to December 2018. The detector was set to take a single measurement of the equivalent ambient dose H*(10) every 15 min, thereby collecting more than 184,000 values over the five-year period under consideration. The detector&rsquo;s sensitivity to the short-lived radon progeny was verified in a preparatory study performed by means of simultaneous radon flux measurement on field. Variations induced by meteorological events as well as variations potentially induced by seismic events were investigated by implementing different data analysis techniques. In the latter case, a retrospective preliminary study was conducted, applying the ARFIMA class of models in order to test the method&rsquo;s potential. The analysis techniques, results and potential applications are presented and discussed in this article