Analysis of the influence of Solar activity and meteorological parameters on the 7Be concentration at the ground atmosphere

Zbog svoje radioaktivne i toksične prirode, lokacije i načina nastajanja, izotop 7Be ima višedecenijsku pažnju u oblasti radioekologije i meteorologije, pre svega kao trasera u praćenju kretanja polutanata i vazdušnih masa. Shodno tome, bilo bi poželjno ustanoviti model vremenske distribucije ovog izotopa, koji bi omogućio predikciju njegove koncentracije. Kao doprinos poboljšanju odabira parametara za simulacione modele, cilj ovog istraživanja je da se ispita uticaj aktivnosti Sunca i pojedinih meteoroloških parametara na koncentraciju 7Be u prizemnom sloju atmosfere. Za potrebe ovog istraživanja, korišćeni su rezultati gamaspekrtometrijskog odreĎivanja koncentracije aktivnosti 7Be u dva medijuma (vazduh – uzorci aerosola i ukupni depozit) tokom perioda 1995–2017, sprovedenih u Laboratoriji za zaštitu od zračenja i zaštitu životne sredine, Instituta za nuklearne nauke “Vinča”. Metodama Furijeove transformacije i linearne regresije, primenjenim u ovoj disertaciji, po prvi put je uočena mogućnost uticaja smera Sunčevog magnetnog polja na koncentraciju 7Be u uzorcima vazduha. Pokazalo se da bi uključivanje perioda promene od 22 godine moglo dovesti do poboljšanja kvaliteta njene simulacije.Due to the 7Be isotope is radioactive and toxic nature, as well as its location and way of its production, it has decades of attention in the field of radiochemistry and meteorology, primarily as a tracker in monitoring the movement of pollutants and air masses. Accordingly, it would be desirable to establish a time distribution model for this isotope, which would allow a prediction of its concentration. As a contribution to improving the selection of parameters for simulation models, the aim of this study is to examine the influence of solar activity and individual meteorological parameters on the concentration of 7Be in the ground level atmosphere. For the purposes of this research, the results of gamaspekrtometric determination of the activity concentration of 7Be in two media (air - aerosols and total deposit) were used. They carried out at the Laboratory for Radiation Protection and Environmental Protection, Institute for Nuclear Sciences "Vinča" and cover the period during 1995-2017. The methods of the Fourier transform and linear regression, applied in this dissertation, for the first time have seen the possibility of influencing the direction of the Solar magnetic field to the concentration of 7Be in air samples, and it has been shown that the inclusion of a period of change of 22 years can lead to a decline in the quality of its simulation

Comparatioions of two methods for HPGe detector efficiency calibration for charcoal canister radon measurement

The charcoal canister method of radon concentration estimation according to US EPA protocol 520/5-87-005, is the most widely used method of screening. This method is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. For the purpose of gamma spectrometry, appropriate efficiency calibration of the measuring system must be performed. The most usual method of calibration is using standard canister, a sealed canister with the same matrix and geometry as the canisters used for measurements, but with the known activity of radon. In absence of standard canister, a different method of efficiency calibration has to be implemented. This paper presents the results of efficiency calibration using EFTRAN efficiency transfer software. Efficiency was calculated using soil matrix cylindrical secondary reference material as a starting point. Calculated efficiency is then compared to the one obtained using standard canister and applied to a realistic measurement in order to evaluate the results of the efficiency transfer.2nd International Conference on Radiation and Applications in Various Fields of Research (RAD), May 27-30, Niš, 2014

Comparison of results of radon level measurements obtained with charcoal canisters and airthings detectors during summer at TCAS

Radon is the main source of natural radiation and has been classified as a carcinogen by the relevant international organizations. It is released from soil, water, building materials in the atmosphere and the most significant part of dose due to radon is received by the inhalation of 222Rn and its progeny in closed spaces. At Technical College of Applied Sciences in Zrenjanin (TCAS) two-day long radon concentration measurements were performed in eight rooms during summer holidays by using open charcoal canisters (EPA520 method) and by simultaneously engaged active type Airthings radon detectors. During the measurements open charcoal canisters and Airthing detector were placed one near the other at the table of about 1 m height, windows and doors in the rooms were kept closed and rooms were also not ventilated for some time before the start of the measurements. These studies were performed in order to check radon concentration levels at TCAS as part of the project Radon Level Measurement activities financed by the Provincial Secretariat for Higher Education and Scientific Research. The results were compared and discussed.RAD 2023 : 11th International Conference on Radiation Natural Sciences, Medicine, Engineering, Technology and Ecology (RAD 2023) 19–23.06.2023; Herceg Novi, Montenegr

Radioactivity of 137Cs in mushrooms

10. međunarodni skup "Sigurnost i kvalitet hrane" : Maj 13. 2022

Interlaboratory comparison material homogeneity testing

The homogeneity of fertilizer samples for interlaboratory gamma-ray spectrometry comparison was tested by determination of the total. count rate and the count rates for two U-238. lines, one K-40 line and one common U-235 and Ra-226 line. Homogeneity testing was accomplished by determination of the minimum, maximum, mean and standard deviation for each parameter and comparison of their standard deviations with predefined tolerances, by Cochrans test, and by a one-way ANOVA. The standard deviations were all less than these tolerances. All samples passed Cochrans test and the one-way ANOVA test for homogeneity

Quality control of HPGe detectors for gamma spectrometry of environmental samples

Quality assurance and quality control (QA/QC) is a series of procedures aimed at verifying the validity of the measurement results and are defined in the Standard ISO 17025/17. QC should be planned, described in the quality control documentation, performed in a systematic manner, recorded and reviewed. All proposed measures for QC/QA are implemented in the Radiation and Environment Protection Department of Institute for Nuclear Sciences Vinča, Belgrade. One of these procedures prescribes a regular quality control of the instruments used for the measurement. In this paper, the quality control of three High Purity Germanium (HPGe) detectors, produced by Canberra, are presented. The accuracy and reproducibility of gamma spectrometry systems are verified on a weekly basis. Total background count rate is used to verify that the detector and shield has not been contaminated. Measurement of the total activity of calibration source is used to check the efficiency calibration and general operating parameters of the system such as peak shape and peak drift. These values are observed and verified if they are within the acceptance limits. For that purpose, 60Co and 133Ba point sources, produced by Czech Metrology Institute and traceable to Bureau International des Poids et Mesures (BIPM), are used. The acceptance limits for each controled parameter are defined according to the statistical analysis of the previous QC period. The acceptance limits are set to be ±2σ and ±3σ of the mean value taken over a previous year. Results of the QC measurement falling between ±2σ are considered to be satisfactory, the ones between ±2σ and ±3σ are warning and those exceeding ±3σ indicate that a problem with the measurement system has occurred. Analysing the QC data acquired for 2021, we can conclude that major part of parameters were within the limits of acceptance. Occasional discrepancies were minor and were addressed immediately. Discrepancies of the peak shape were corrected simply by additional cooling of the instrument, peak position by performing an energy calibration and background was corrected by ventilating the laboratory.Twentieth Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 30 – December 2, 2022, Belgrade, Serbi

Seasonal variations of naturally occurring radionuclides and 137cs in the leaves of deciduous tree species at sites of background radioactivity levels

Activity concentration of natural radionuclides and 137Cs were studied in leaves of the deciduous trees. In the spring and autumn season, leaves were collected in the area of normal background radiation levels represented by city parks in a multi-year period (2002-2012). Measurements by means of gamma-ray spectrometry showed 226Ra and 210Pb seasonal accumulation in leaves, while 238U and 235U could be detected only in autumn. Difference between seasons was not found significant for 40K and 137Cs. The study of radionuclides transfer factors was conducted by analyzing its relationships with basic soil properties at the beginning and the end of the vegetation period. © 2019, Editura Academiei Romane. All rights reserved

Radionuclide content in samples of berries

After the Chernobyl accident, the presence of artificial radionuclides in foodstuff, especially in berries (blueberries, cranberries etc.), was heightened. Legislative, presented in Rulebook on Radioactivity Control of Goods During the Import, Export and Transit (Official Gazette RS, 86/19 and 90/19), establishes the mandatory gamma spectrometry measurement of berries, while the limits of radionuclide content in these products is defined in the Rulebook on Limits of radionuclide content in drinking water, foodstuff, feedstuff, medicines, items of general use, building materials and other goods placed on the market (Official Gazette RS, 36/18). At the Radiation and Environment Protection Department of the Vinča Institute of Nuclear Sciences, measurements of the radionuclide activity in foodstuff are readily performed. In this paper, the results of the investigation of berries in the period of 2014 to 2021 are presented along with the amount of this produce that can be ingested by the various age groups without exceeding the annual effective dose limit of 0.1 mSv

Activity concentration of 210Pb in aerosol in Serbia in the period of 2014-2020 and the comparison between results from urban and rural sampling stations

Aerosol sampling and monitoring of naturally occurring and artificial radionuclides is readily performed within the frame of Environmental radioactivity monitoring in the Republic of Serbia. It provides information important for the preservation of the public health and the environment from the harmful effects of ionizing radiation. This type of monitoring has been performed in Institute of Nuclear Sciences Vinča for more than 30 years now. The radionuclides that are measured are: naturally occurring 210Pb, artificial radionuclide 137Cs and cosmogenic radionuclide 7 Be. Particle reactive radionuclides such as 210Pb and 7 Be have been used as atmospheric tracers for studying environmental processes such as cloud scavenging and precipitation [1], aerosol transit and residence times in the troposphere [2], and aerosol deposition velocities [3]. The fission product 137Cs is an indicator of anthropogenic pollution caused by nuclear weapon atmospheric tests and nuclear power plant accidents. Seasonal variation in 137Cs in air is an indicator of the stratosphere-troposphere exchange processes [4]. In most aerosol samples in later years, the activity concentration of 137Cs is below the minimal detectable activity and therefore it was not taken into the consideration in this paper. The activity concentration of 7 Be is dependent on the movements of large air masses and vertical mixing in the atmosphere and also was not discussed in this paper. In this paper, the activity concentration of 210Pb in aerosol samples, obtained over the period from 2014. to 2020., was discussed. Sampling is performed using constant air flow pumps and Whatman filter papers on 6 measuring stations distributed in various parts of the country. Three stations are in urban areas of cities of Belgrade, Vranje and Zaječar and other three are in rural areas (Palić and Zlatibor) or removed from the urban part of the city (Meteorological station in Vinča). The monthly composite sample from each sampling station was ashed at the temperature below 400o C. After ashing, the residue aerosol is measured on HPGe detectors using a standard gamma spectroscopy method [5]. The results for 210Pb are of the order of magnitude of 10-4 to 10-3 Bq/m3 . The activity concentration in all investigated samples shows temporal dependence with the maxima in the winter months and minima observed during the spring and summer. Also, the comparison between the results obtained from the rural and urban locations was performed in order to investigate the influence of the air pollution present in the urban areas on the activity concentration of 210Pb. The values, obtained at stations located in rural parts, ranged from (0.056 – 3.3) mBq/m3 , while for stations located in urban areas the range was from (0.125 – 2.9) mBq/m3 . It can be seen that from all the data that the activity concentration of 210Pb was lower in rural areas. Two outliers were observed at Palic station, located in the plane and along the path of the prevailing south – east wind, possibly bringing aerosols from Deliblatska pescara (Deliblato Sands) [6].IV International Conference on Atmospheric Dust : October, 4-7, 2021, Torre Cintola Conference Centre | MONOPOLI | Italy

Quality control of gas flow proportional counter for beta spectrometric determination of 90Sr

In the Radiation and Environmental Protection Department, Vinča Institute of Nuclear Sciences, the validated radiochemical analytical method for 90Sr determination in environmental samples is used. The Laboratory for Radiation Measurements within mentioned Department is accredited according to ISO/IEC 17025. The activity of 90Sr is determined indirectly, by beta counting of its daughter product 90Y, and after established radioactive equilibrium during 18 days from the moment of 90Y radiochemical separation. Beta spectrometry by gas flow proportional counter Thermo Eberline FHT 770T is used for detection of 90Sr activity in investigated samples. In order to assure the reliability of the measurement results in accordance with Standard ISO/IEC 17025:2017, quality assurance and quality control (QA/QC) corresponding procedures need to be applied. For this purpose, activities ought to be planned in a systematic manner as described in the quality control documentation. The efficiency calibration of the detection system needs to be performed in a proper manner. The calibration of the detector for beta counting is performed using the Sr-90 certified radioactive standard point source (9031-OL-335/11, produced by Czech Metrology Institute) which is traceable to Bureau International des Poids et Mesures (BIPM). As lowlevel measurements require strict QA/QC requests, the accuracy and reproducibility of measurement systems must be verified periodically. A regular internal quality control of the gas flow proportional counter is performed once a week. Quality control activities include the background measurement and checking of efficiency using adequate radioactive standard source. The measurement values are recorded and verified if they are within the acceptance limits. The obtained results together with acceptance limits during the period of 3 months are graphically presented in control charts. The acceptance limits are set to be ±2σ and ±3σ in relation to the calculated mean value and standard deviation. The results of QC verification within ±2σ are considered to be satisfactory, those within ±3σ are warning, while those that exceeding ±3σ indicate that there is a problem with the measurement system. Consequently, the analysis of causes and design, as well as the application of corrective measures is needed.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi