Cosmic-ray muography is a well-established technique for examining large-scale structures (e.g., volcanoes, pyramids, and underground geological formations) and for imaging high-density objects composed of high-Z materials, such as nuclear reactor fuel and waste containers. Historically, muography techniques have relied primarily on either muon absorption within very thick material layers or the multiple Coulomb scattering of muons traversing high-density materials. Consequently, applying muography to small-scale structures composed of low-Z, low-density materials has remained a significant challenge. In this work we adopt a complementary approach in which the image itself is formed from the selected trajectories of muons registered by a dual muon tracker that are in coincidence with muon secondary particles, which are produced within the sample volume and subsequently detected by surrounding scintillation detectors. This study investigates the interactions between cosmic-ray muons and several pure, low-Z materials using a specialized experimental configuration comprising an ultra low-background high-purity germanium (HPGe) detector coupled with plastic scintillators. The experimental findings are supported by Monte Carlo simulations developed using the GEANT4 software toolkit, facilitating the determination of effective cross-sections for these low-Z materials. The obtained crosssections for production of low-energy continuum, combined with a self-absorption effect, reproduce the measured low-energy continuum maximum at around 100 keV. The practical application of muon-induced secondary particles for imaging was realized through the development of a dual muon tracker system, utilizing plastic scintillation detectors to register the secondary emissions. This system was employed to image low-Z objects, optimizing operational parameters to minimize acquisition time while maximising image resolution. Furthermore, comprehensive GEANT4 simulations of the imaging system were conducted to explore possibilities for future optimization.

Radiological screening of construction materials is conventionally performed on bulk samples, yet occupants are exposed to fine, abradable, and respirable fractions. This study examines how particle-size distribution (PSD) governs the redistribution of 226Ra, 232Th, 40K, and anthropogenic 137Cs in construction materials and in ash from domestic biomass heating. In total, 27 materials were analysed by high-resolution HPGe gamma spectrometry, with granulometric segregation at coarse (PSD3) and fine (PSD7) resolution. PSD3 showed no monotonic effect, whereas PSD7 revealed a systematic rise of the activity concentration index toward the finest fractions. 40K and 137Cs showed the strongest particle-size dependence, indicating preferential accumulation in the fines; 137Cs was detected only in biomass-ash pellets, where it was enriched in the fines (EF = 2.73 relative to bulk; a single-material case study). Two models are proposed: a physically grounded surface-controlled model and a descriptive granulometric enrichment factor for material ranking, both fitted to the present dataset. A fraction-resolved dose assessment showed that the internal hazard index (Hin) rises toward the fines and exceeds unity (≈1.1) in the respirable ash and fireclay fractions even though their bulk values remain acceptable. Bulk screening, therefore, underestimates the dose-relevant burden carried by the fine fractions that workers and households actually inhale.

In experiments searching for rare nuclear events (neutrinoless double beta decay, dark matter, etc.) detailed knowledge of the background is necessary to achieve reliable analysis and interpretation of experimental data. In ground-based laboratories, the significant contribution to the background of the detector spectrum originates from interactions of cosmic rays with materials in the vicinity of the detector (shielding and building) and the detector crystal itself. In this paper, the Monte Carlo simulations were performed to analyze and quantify the cosmic ray-induced nuclear processes occurring in the vicinity of the shielded HPGe detector system, as well as to compare simulated and experimentally obtained spectra. The influence of the building on the modification of the HPGe spectrum was studied and quantified. Additionally, deconvolution of the spectrum was performed, allowing the selection and presentation of the spectral events arising from the different processes taking place inside the Ge crystal.

Many techniques have been developed for analysis of primary photon beam spectra of Linear Medical Accelerators, based on experimental measurements, as well as on Monte-Carlo simulations, while the scattered spectral distribution was less often investigated. In this paper, scattered bremsstrahlung energy distribution and intensity in the vicinity of a linear medical accelerator with 6 MeV electron beam energy, were explored using Monte Carlo simulations. The obtained simulated count rate of scattered bremsstrahlung in the region of 0 keV-3600 keV was found to be in relatively good agreement (≈15(4)%) with the measured count rate in the same energy region. The highest simulated flux of scattered bremsstrahlung was found at the detector position above the primary collimator (43.4·109 photons m-2 s-1 with associated reached statistical uncertainty less than 1 %), including the highest intensities of the annihilation line and 59.3 keV X-fluorescence tungsten lines, with the maximum of continuous scattered distribution at about 200 keV for this position. Furthermore, the spectra and fluxes of coincidence events (multiple scattering and annihilation photons) generated by single primary photons were obtained in simulations and analyzed.

Thermal and mineral waters represent a complex multifunctional natural resource that has been used for various purposes throughout human history. The physico-chemical characterization of thermal and mineral waters is a comprehensive process that integrates knowledge and practice from different scientific fields. When used in direct contact with human skin, whether for bathing or for use in topical products, a toxicological analysis of thermal and mineral waters must also be performed. This work is an example of a multidisciplinary approach to investigate the safety of concrete thermal and mineral water from the Pannonian Basin for use in cosmetics. A detailed physicochemical characterization was performed together with the subsequent safety assessment of the final cosmetic product, coupled with cheminformatics and bioinformatics tools used to predict physicochemical properties, pharmacokinetics, determination of descriptors to assess bioactive potential and evaluation of possible biological pathways and interactions. The results show that the tested thermal and mineral water is a promising resource for use in cosmetic products that can help maintain skin integrity and improve its condition. The toxicological evaluation showed that the tested water is acceptable as an ingredient in a face cream for adults, excluding pregnant and breastfeeding women. The results are discussed in detail and guidance and comments on outstanding issues are provided.

This study deals with measurements of radon concentration in the kindergartens of the mining area where high levels of radon have already been detected in dwellings. Three surveys of measurements were performed with charcoal canisters in occupied and non-occupied rooms. The findings revealed that more than 90% of measurement results were above 100 Bq m-3. There is a significant difference between ground and floor radon concentrations, but no difference between types of floor coverings, nor the age of construction. Some measures were proposed to mitigate radon levels.

Cosmic -ray muography has been used for the inspection of geological and industrial structures (e.g. fuel in nuclear reactors). However, the muon imaging of small structures with low atomic number and density was not yet solved appropriately. Completely new imaging method by cosmic -ray muon s, based on the detection of secondary produced radiation in object material has been demonstrated by our research group. Taking advantage of the production rate of secondaries in the target materials, detected in coincidence with muons by plastic scintil lator detectors, together with muon tracker, the first cosmic -ray muon images of bone and soft tissue were created. These pictures represent the first radiographies of structures of organic origin ever recorded by cosmic rays. The research using Monte -Carlo (MC) simulations, done by Geant4 software, includes simulations of the interactions of cosmic -ray mu ons with different detectors and different target materials in order to optimize the experimental setups and further investigate the processes leading to image creation. In this work, we will present two experimental setups in Novi Sad (MUCA) and Budapest (COMIS), used for muography of different test materials and the obtained images via those setups. MUCA - Muon Camera setup consists of 4 plastic scintillation detectors (5 0cm × 50cm × 5cm) and muon tracker (5 CCC boards 25cm x 25cm) placed above the object imaged. COMIS (Cosmic Muon Induced Secondaries) experimental setup is comprised of muon tracker (5 CCC boards 50cm x 50cm, with 2mm resolution) placed below the object im aged, 4 plastic scintillation detectors (50cm × 50cm × 5cm) positioned around the object and 4 plastic scintillation detectors (25cm × 25cm × 5cm) under the target volume. The aim of this research is to provide imaging and composition study of various obje cts, emphasizing low atomic number and density materials, using only natural omnipresent cosmic radiation.

This paper analyzes 96 samples of cement, 55 samples of chamotte, and 21 refractory products (4 refractory cement, 5 refractory bricks, 10 refractory mass, and 2 refractory sand) using low-level gamma spectrometry. Radiological risk is estimated through absorbed dose rates and annual effective dose, while results were compared with similar studies and discussed. Results indicate the need for radioactivity control of these building materials, since high dispersion of the activity concentrations of naturally occurring radionuclides is present, as well as high activity concentrations of 226Ra and 232Th compared with other building materials.

During the 1999 war, NATO forces used >30,000 rounds of depleted uranium (DU) ammunition, with a total mass of around 10 tons, on the then Federal Republic of Yugoslavia (now the Republic of Serbia). After the war, between 2002 and 2007, land decontamination was carried out. This paper presents a comprehensive study of the impact of depleted uranium on soil and water in Serbia, with a special focus on contaminated locations in southern Serbia. The study includes key results from analyses of uranium isotopes 238U and 235U in soil and water, and their ratio (235U/238U) before and after land decontamination. Data from the UNEP international mission, as well as other studies from the end of the war to the present, were analyzed. Reported values of 238U and 235U in the remaining penetrators were 12.7 ∙ 106 Bq/kg and 1.9 ∙ 105 Bq/kg, respectively. The maximum measured values of 238U in contaminated soil were up to 307,000 Bq/kg, and 235U values were up to 3920 Bq/kg. The established 235U/238U ratios indicate that the contamination of soil with DU was near the impact sites of the penetrators, while values in more distant samples were within natural levels. It was found that the water in southern Serbia was not contaminated with DU and that the concentrations were comparable to other studies. After the remediation measures were carried out on contaminated sites, no DU presence was detected in soil or water. This is confirmed by DU monitoring results in Serbia conducted from 2013 to 2023. Additional studies for other parts of Serbia show no evidence of environmental contamination with DU, as all results are comparable to reported global values. Furthermore, to minimize any potential health risks to people, continuous monitoring of uranium at high-risk locations in southern Serbia is necessary.

The results and conclusions of the national comparison of indoor radon measurements in 2023 in Serbia are presented in this paper. The participants were three accredited laboratories that use the same method for indoor radon measurement, based on adsorption to activated charcoal, according to international standard protocol. The results of intercomparison were evaluated using the z-score performance criteria. Also, the limitations and advantages of several different methods for indoor radon testing, as well as the possible use for radiological risk assessment are discussed.

One of the major demands in gamma spectrometry of environmental samples is the accurate determination of activity concentration of present radionuclides (naturally occurring and those of artificial origin), due to the fact they are commonly of relatively low content. Thus, all these measurements have in common that the detection limit, in the spectral region of interest should be as low as possible. For this reason, the construction of a good passive, as well as active shield requires a detailed knowledge of the origin of the background events in the absence of an environmental sample. In addition, an analysis of the impact on detection limits due to the presence of the sample itself is also important. Also, the knowledge of the statistical basics for low-level counting is helpful to enable the best choice of detector characteristics (relative efficiency, peak to Compton ratio, resolution), measuring time, and required level of precaution against the different background contributions.In this paper, the background spectra of several gamma spectroscopy systems (with passive and active veto shields) are analyzed and discussed, regarding their capabilities for measurements of environmental samples. Furthermore, various environmental samples are analyzed by low-level gamma spectrometry, including the sample measurements in the presence of an active veto shield against cosmic-ray muons. The disturbance of radioactive equilibrium between members of radioactive series in the samples is commented on, together with the possibility of use of certain gamma lines (including their interference and the corresponding intensities) for radionuclide activities determination.

In the ceramic industry, the quality of the final ceramic tile as well as the possibility of its use depends on the quality and characteristics of the starting raw materials. One of the potential raw materials that can be used in the production of ceramic tiles is kaolinized granite, and it is necessary to examine its characteristics. In this research, the kaolinized granite of the Jadar block, northwestern Serbia, from the Beli Majdan surface mine, Jadranska Lešnica, was examined. Chemical analysis, X-ray diffraction analysis (XRD), and differential thermal analysis (DTA) were carried out. Ignition tests of the prepared composites were also conducted at three selected temperatures (1000, 1100, and 1250°C), where total linear shrinkage and water absorption were determined. The activity concentrations of natural radionuclides and the artificial radionuclide 137Cs were determined using the gamma spectrometry method, and then the radiation risk for the external exposure of workers when working with this raw material was assessed. For the samples with the highest content of 226Ra, radon exhalation measurements were performed with the RAD7 device, and the values of the radon emanation coefficient were determined, as well as the values of alpha dose equivalents, which quantified the potential internal exposure of workers. The results of the chemical analysis showed that the content of Al2O3 in the examined composites ranged from 19.11-21.00%, and the content of Fe2O3 from 1.53-1.72%. Additionally, the K2O content in the tested composites ranges from 4.01-5.46%, which indicates the presence of K-feldspar and muscovite, and the Na2O content from 1.82-2.61%. Based on XRD analysis, it was established that the mineral composition of kaolinized granite includes quartz, feldspar, mica, calcite/dolomite, and kaolinite minerals. DTA analysis indicates the occurrence of minor endothermic processes at 488.05°C and 558.12°C, as well as an exothermic process at 980.8°C. The color of the ignition is brick red to dark brown red. A trend of increasing linear shrinkage and decreasing water absorption with increasing ignition temperature was observed with the normal appearance of the samples. The average activity concentration of natural radionuclides are around and below the average values for building materials, expect for 40K. The values for 137Cs are below the values measured in soil. Annual effective doses estimated for external exposure are below 1 mSv y-1, which indicates that there is no increased radiation risk when working with this raw material. The values of the radon mass exhalation rate are in the range of 61-113 mBq kg-1 h-1, and the values of the radon emanation coefficient are 6.3-8.4%. The average value of the alpha dose equivalent is 1mSvy-1, which indicates a potential exposure to radon below 100 Bq m-3. Based on the obtained results, it can be concluded that kaolinized granite is a high-quality and radiologically safe raw material for making ceramic composites in the production of ceramic tiles. It has all the necessary characteristics to partially or completely replace feldspar in ceramic composites.

For the production of ceramic tiles, it is necessary to use high-quality and economical raw materials, which will optimize the properties of the final product and meet the prescribed standards. For this reason, it is necessary to examine the properties of each potential raw material. This paper examines radioactivity and technological properties of kaolinized granite from the Motajica mine, in Bosnia and Herzegovina. Chemical analysis, X-ray diffraction (XRD), and thermal analysis (DTA) were carried out. In order to examine the technological (ceramic) properties of this raw material, ignition tests of the composite obtained by introducing kaolinized granite (with a content of 25 %) into the standard factory series of ceramic tiles were conducted at four selected temperatures (1050, 1100, 1120, and 1150 degrees C). Total linear shrinkage, flexural strength, and water absorption were determined for the produced biscuit. Using gamma spectrometry, the activity concentrations of radionuclides Ra-226, Th-232 and, K-40 were measured, and then the radiation risk for external exposure of workers in the industry was assessed using hazard indices and doses. The radiation risk from the use of manufactured unglazed ceramic tiles in houses was also assessed. Statistical analysis of radionuclides for 100 samples of kaolinized granite was performed using descriptive statistics and hierarchical cluster analysis (HCA). It was observed that the average values of Ra-226, Th-232, and K-40 are above the average for building materials in the world and amount respectively to 122 Bq kg(-1), 96 Bq kg(-1), and 1068 Bq kg(-1). All other obtained values indicate that it is a quality raw material that, despite having an increased content of radioactive elements compared to the world average, does not represent a radiological hazard for workers and people who stay indoors on an annual basis. The tested raw material satisfies all technological criteria for further use and can be considered a desirable ingredient of ceramic composites because it can partially or completely replace feldspar.

Izloženost ljudske populacije prirodnom jonizujućem zračenju je kontinualni i nezaobilazni deo života na Zemlji. Najveći doprinos izloženosti populacije potiče od kosmičkog zračenja i radionuklida prisutnih u Zemljinoj kori. Prosečna izloženost kosmičkom zračenju doprinosi sa oko 16% ukupnoj godišnjoj efektivnoj dozi koja potiče od prirodnog zračenja, sa prosečnom vrednošću od oko 0,4 mSv godišnje. Procena doze koja potiče od izloženosti ljudske populacije kosmičkom zračenju je neophodna kako bi se bolje razumela celokupna izloženost prirodnom radioaktivnom zračenju. U ovom radu korišćen je Monte Karlo metod u Geant4 simulacionom paketu radi procene jačina apsorbovanih doza i godišnjih efektivnih doza kosmičkog zračenja na nivou mora i na različitim nadmorskim visinama. Procenjene su i efektivne doze koje primi pojedinac u slučaju nekoliko tipičnih letova. Dobijeni rezultati su upoređeni sa rezultatima sličnih studija dostupnih u literaturi.

The main purpose of this paper was to determine tritium concentration in surface water samples, using liquid scintillation counting. Surface water samples were collected from the Mlaka creek on three different locations near PC "Nuclear Facilities of Serbia". The importance of tritium monitoring around nuclear reactors and nuclear waste storages is due to prevention of possible internal exposure through ingestion of drinking waters with elevated levels of tritium from existing water supply in their nearby. Tritium concentrations that have been measured during the period from 2017 to 2022 ranged from less than 2 Bq/L to 103 Bq/L.

This paper presents the results of gamma spectrometry measurements of natural radionuclides (226Ra, 232Th, and 40K) in some floor and wall ceramic tiles produced in Serbia and used in homes and workplaces. The level of radioactivity of some ceramic tiles produced in Serbia by two major manufacturers–Zorka Keramika and Toza Markovic was examined. The measured mean value of the activity concentration of 226Ra, 232Th, and 40K exceeds the average values in the world for building materials with values of 67.2±6.9 Bq kg-1 for 226Ra, 57.4±4.7 Bq kg-1 for 232Th and 808±48 Bq kg-1 for 40K. Based on these calculated values, the representative level index gamma index, associated with gamma radiation, whose average value is 0.78±0.06, and annual effective dose, whose average value is 0.117±0.009 mSv y-1 for home was obtained. Estimated values fulfill all the recommendations of the European Union for building materials, thus analyzed materials are considered not to be a health hazard for the public.

Table salt commonly refers to a refined salt containing primarily sodium chloride. During the refining process, salt is often treated with chemicals to remove all impurities and also to achieve the desired color and structure of the final product. Himalayan salt is usually less processed than regular refined table salt and may contain trace nutrients and minerals which are assumed to provide various health benefits. However, some of these impurities (such as radionuclides and heavy metals) may also lead to potentially harmful effects. This study was conducted to investigate specific activities of natural radionuclides in five different samples of Himalayan salt available in Serbian markets. Average specific activities ± standard deviations of 226Ra, 232Th, and 40K were 1.4 ± 0.2, 0.5 ± 0.3, and 113 ± 48 Bq kg-1, respectively. The annual effective doses from radionuclides and radiological risks were estimated. The results indicate that Himalayan salt consumption is radiologically safe in all age groups.

The activity concentrations of 238U, 226Ra, 232Th, and 40K in 56 phosphate samples (phosphate rocks, monocalcium, and dicalcium phosphates) used in Serbia were determined using gamma spectrometry to assess the exposure level of workers. Radium equivalent index (Raeq), absorbed gamma dose rate (DR), annual effective dose (AED), and excess lifetime cancer risk (ELCR) were evaluated. The highest external exposure was recorded when working with phosphate rocks, as Raeq, DR, and ELCR exceed the recommended/average values. The annual effective doses for workers in the phosphate industry are below 1 mSv y−1 and comparable to the values from other studies.

Low-energy continuous gamma radiation with a maximum energy distribution at similar to 70 keV reaches the Earth's surface from the upper hemisphere. In addition to components resulting from cosmic-origin low-energy gamma radiation, there is also a prominent contribution arising from gamma photons emitted by environmental ra-dionuclides, which are backscattered by air above ground (commonly referred as "skyshine" radiation). Since both components are covering the same energy region of gamma radiation (mainly 30 keV-350 keV), it is not simple to determine the separate contributions of each radiation component to the total gamma flux. The effi-cient way to solve this long-standing problem is to study the backscattering of gamma radiation on the atmo-spheric air by Monte Carlo simulations. In this work, the simulations were performed in order to obtain air-backscattered spectra, as well as gamma photon fluxes which can be expected for specified activity concentra-tions of natural radionuclides (K-40, Ra-226, Th-232) distributed in the ground. The simulation results were compared with experimental measurements of low-energy photon flux in the open area from the upper hemi-sphere. Furthermore, the influence of height above ground and distance from the shore on the skyshine intensity reduction is explored.