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Item type:Publication, Nuclear track detector response to energetic heavy ions: study case(Springer, 2020-05-01)Nuclear track methodology (NTM), is employed to analyze PADC detectors response to different energetic ion beams. Due to the passive device linearity response to heavy ions with LET-value > 30 keV μm−1, they are employed in several fields e.g. nuclear industry, medical, environmental radiation and aircraft dosimetry. To further improve application, PADC-detectors were irradiated by beams of 4He (150 MeV nucleon−1), 12C (390 MeV nucleon−1) and 56Fe (465 MeV nucleon−1), in relatively low-dose range ≤ 1 mGy. Results provided, through etched track analysis, valuable information of interest for NTM when high LET ionizing radiation is involved. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Comprehensive study of natural radioactivity in building materials: A case study in Ica, Peru(Multidisciplinary Digital Publishing Institute (MDPI), 2024-03-01)This study evaluates radon exhalation rates and assesses the potential radiological risks of external exposure to primordial radionuclides in building materials employed in the Ica region of Peru, particularly those with high uranium content. The radon exhalation rates are currently measured using a combination of a closed chamber and an active monitor. We proposed a novel method that effectively ensured a hermetic seal for the closed chamber and guaranteed that the efficient maintenance of secular equilibrium. The obtained results ranged from below the detection limit (BDL) to a maximum of 52.3 mBq · kg−1h−1. Gamma spectrometry was employed to measure the concentrations of radionuclides by utilizing a 3′ × 3′ NaI detector. The analysis of cement samples revealed a strong positive correlation between the activity concentration of radium and the radon exhalation rate. The activity concentrations for radionuclides varied, with values ranging from BDL to 60.6 mBq · kg−1h−1 for 226Ra, BDL to 22.3 mBq · kg−1h−1 for 232Th, and BDL to 1074 mBq · kg−1h−1 for 40K. These findings contribute valuable insight to decision-making processes in the Peruvian construction industry, particularly regarding material safety and radiological risk management. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mapping the spatial distribution of natural gamma dose rates as a baseline study in the Province of Asti, Italy(Multidisciplinary Digital Publishing Institute (MDPI), 2024-06-01)Natural background gamma rays and their effects on human health are essential components of both radiation protection and public concern. In the frame of these aspects, the mapping of the natural gamma dose rate values of the Province of Asti is given. The Asti Fire Brigade Command approved a project relating to the mapping of gamma radiation from the natural background in the territory of Asti. The project engaged both the Nuclear, Biological, Chemical, and Radiological (NBCR) and Topography Applied to Rescue (TAS) components of the Asti Command. Skilled personnel, comprising level 1 TAS operators for data collection and level 2 TAS operators for cartographic analysis, were deployed across the six working days. The methodology involved the use of two digital handheld radiation G-M detectors, in conjunction with a portable GPS unit, including the Global Mapper software. One of the significant findings of this study is the observation that the natural gamma dose rate levels were 201.25% higher in the streets of the city center compared to other areas, predominantly because the building materials in these locations contain a higher amount of natural radionuclides. The results indicated that the level of natural gamma dose rates in the studied region is close to the global average value. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Monte Carlo Simulation of a Simple and Fast Method to Experimentally Determine the Partial Sensitivity of a Bare LR-115 Detector Using Planar Alpha Sources(RELX Group (Netherlands), 2023-01-01)Partial sensitivity of the bare LR-115 detector (KB) to radon or thoron, or any of their airborne progeny, is an essential component in the detector's calibration factor. Its experimental determination is complex, requires expensive and sophisticated instruments and facilities, and is time consuming. Using the TRACK_TEST and SRIM programs, and Monte Carlo simulations, the possibility of a simple and fast method to determine KB experimentally was demonstrated. The method is based on calculations of the average value of detection efficiencies (i.e., the cumulative efficiency) for alpha particles emitted by a planar alpha source placed at different distances from detectors. Source radius can be estimated from the energy of emitted alpha particles, detector radius, and parameters dependent on etching conditions. Varying the emission energy of alpha particles, the source and detector radii, and the source-detector distance step length, an average value of 0.02 tracks. cm−2 per Bq.d.m−3 (0.22 cm) was obtained assuming standard etching conditions. In addition to alpha electrodeposited sources, sealed sources such as those built with anodized aluminium sheets proved to be suitable for this proposal. Experimentally, KB can be estimated from: track densities registered in detectors exposed at different distances from the source, range of distances that produce visible tracks, and source activity. The developed method is much simpler and faster than the conventional method that uses standard sources of radon and its progeny and large chamber with controlled conditions. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Estimation of Indoor 222Rn Concentration in Lima, Peru Using LR-115 Nuclear Track Detectors Exposed in Different Modes(Multidisciplinary Digital Publishing Institute (MDPI), 2023-06-01)Radon is the main source of natural radioactivity, and its measurement is considered extremely important in radioprotection, given its relationship with the occurrence of lung cancer. In the last two years, measurements of this radioactive gas were carried out in Lima considering a grid of 5 km (Formula presented.) and the population density to determine the number of measurements to be carried out. Cellulose nitrate nuclear track detectors exposed in bare mode and diffusion chamber mode were used to estimate (Formula presented.) Rn concentrations. In diffusion chamber mode, non-commercial monitors and commercial monitors were used. The monitoring results are presented for 43 districts of the Lima Province whose population is approximately ten million inhabitants occupying a total area of 2655.15 km (Formula presented.). Measurements were made obtaining an average concentration of 49 Bq·m (Formula presented.) using bare detectors and 66 Bq·m (Formula presented.) using non-commercial diffusion chambers. Average concentrations obtained by both detector exposure modes were below the maximum concentration recommended by the WHO. A radon ((Formula presented.) Rn) map was also obtained as a visual representation of the (Formula presented.) Rn levels in the Lima province using inverse distance weighting (IDW) interpolation. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Environmental Alpha Radiation from the Soil at a Prehispanic Ancient Sacred Site in Lima, Perú(Polskie Towarzystwo Inzynierii Ekologicznej (PTIE), 2023-01-01)In the present work, we investigate the concentration of radon and its alpha-emitting progeny at the archaeological site of Huaca 20 in Lima, Peru. The site holds significant cultural and historical importance as an ancient pre-Inca ruin, providing valuable insights into the lives and rituals of its former inhabitants. We quantified the radon levels accurately with passive CR-39™ detectors deployed within specially designed chambers at the site for 28 days. In a controlled laboratory environment, we processed the detectors afterward, examining and analyzing the resulting tracks using advanced microscopy and the ImageJ analysis software. The ground-level concentration of radon and its alpha-emitting progeny was determined, revealing elevated levels ranging from 2.4 ± 0.6 to 8.9 ± 0.9 (kBq/m3). These findings underscore the unique presence of radon at Huaca 20 and highlight the potential impact on microorganisms at ground level. Likewise, these results can contribute to studies on the radiological risks faced by visitors, excavators and archaeologists. Finally, we show the spatial distribution of radon concentrations within the site by creating an iso-concentra-tion map. The iso-concentration map reveals a relation between areas with elevated radon levels and the good preservation of funerary contexts. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Assessment of Natural Radioactivity and Radon Exhalation in Peruvian Gold Mine Tailings to Produce a Geopolymer Cement(MDPI, 2023-03-01)Mining generates significant amounts of waste that can represent a source of contamination for areas close to the extraction area, generating a negative impact both on the environment and the health of people. This study aims to evaluate the radiological risk derived from exposure to natural radionuclides contained in tailings from Peruvian gold mines and to establish whether the tailings can be used as raw materials in building materials. The mine tailings come from a mining project in the northern highlands of Peru. Radon exhalation was measured using Rad7 in a closed chamber and activity concentration of 226Ra, 232Th, and 40K radioisotopes by gamma spectrometry using NaI 3” × 3” detector. Maximum activity concentrations measured for 226Ra and 232Th were 15.38 Bq kg−1 and 11.9 Bq kg−1, respectively; meanwhile, activity concentration for 40K ranged from 182.7 Bq kg−1 to 770.8 Bq kg−1. All activity concentrations were below the worldwide average except for 40K. The radon exhalation rate varied from 2.8 to 7.2 mBq kg−1 h−1. The gamma index (Iγ), and radiological parameters, including the Radium equivalent activity (Raeq), and the external hazard index (Hex), being below the recommended levels by UNSCEAR, ensure the safe use of these mines tailing to produce a geopolymer cement. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Simulation of diffusion and decay of radon/thoron exhaled from a wall and its newly created progeny. Response of a bare LR-115 detector placed on the wall(Elsevier BV, 2025-06-01)Monte Carlo techniques were used to simulate the air diffusion of exhaled radon/thoron atoms from a wall, the formation and decay of different radioactive species during transport, and the response of a bare LR-115 detector placed on the exhaling surface. The spatial distributions of radionuclide decays and the detector's partial sensitivities to radon/thoron and their progeny were determined. The simulation results were numerically validated through comparisons with published theoretical and experimental data. From the simulated experiments, the contributions of different species to the total track density and what the detector might measure in the studied configuration and assumed parameters were inferred. It was shown that near the wall, where the effective volumes of all species are located, the number of radon atoms was approximately constant, while that of thoron decreased to about 30% relative to the number of exhaled atoms, and the equilibrium factors of both gases were very low. A negligible contribution of 220Rn and 216Po to the track density is expected if the distance between detector's edges and support exceeds 5–6 times the thoron characteristic diffusion length. For similar detector and support sizes, these atoms can significantly contribute to the track density if thoron exhalation rate from wall is high. The advantages and limitations of the detector exposure method for estimating indoor radon concentrations are analyzed. Finally, a simple method is suggested for more accurate radon measurements using the bare LR-115 detector placed on a wall.1