3. Producción
Browse
13 results
Search Results
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Theoretical and experimental study of the LR-115 detector response in a non-commercial radon monitor(Elsevier, 2020-06-01)B.trαcks, a simulation program for SSNTD's sensitivity, has been developed to study the response of LR-115 (cellulose nitrate) and CR-39 (poly allyl glycol carbonate) nuclear track detectors. Detectors are located inside detector holders and are used for radon measurements. The program incorporates a variety of special features gathered together to achieve good agreement between theoretical approach and experimental results. The input parameters to study the detector response are radon exposure, geometry and dimensions of a detector holder (it can be cylindrical, conical or semi-spherical), entrance type for radon gas, detector type, and V function (four different functions were selected from literature). The output results are detector response and radon progeny distribution onto internal chamber walls. In this article, the response of the LR-115, which is placed inside a non-commercial-conductive radon monitor based on diffusion chambers called G2, was theoretically and experimentally studied. The common Monte Carlo simulation procedure and an alternative approach that replicates how monitors are exposed to different radon exposures were used as theoretical approaches. Experimental methodology was conducted in a radon test chamber from Italy (MI.AM s.r.l.). Comparison results of both theoretical and experimental methodology are presented and discussed. One of the major results, among others, shows that the monitor material (conductive or non-conductive) does not influence the LR-115 response. - Some of the metrics are blocked by yourconsent settings
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, Overlapping correction suitable for an LR-115 detector located inside a diffusion chamber(Elsevier, 2021-07-01)A simulation program based on Monte Carlo methods was developed to study the behaviour of the overlapping effect in the LR-115 nuclear track detectors located inside a diffusion chamber. The relation between the non-overlapped tracks and the radon exposure level that the detector was exposed was adopted. This study focuses on very high radon concentration levels found in soil gas, uranium mines, or underground places. These anomalous levels can influence the radiological risk related to inhalation of indoor radon or the spontaneous increases in thermal neutron background. LR-115 detector exposed to anomalous levels can register a large number of latent tracks on its surface. After an etching treatment, some visible tracks can be placed covering one or more visible tracks altering the LR-115 response. In order to develop this work and be more realistic, visible tracks were simulated taking into account radon exposure level, geometry and dimensions of the diffusion chamber, dimensions of the detector, the V function, the etching process and the reading process. Results show that the overlapping effect in the LR-115 inside a cylindrical diffusion chamber exposed to very high levels can be solved with an uncertainty of 5%. The same methodology can also be applied when considering other detectors and geometry and dimensions of a diffusion chamber. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Concentric rings formation on etched LR-115 in bare mode by unconventional exposition(Elsevier, 2021-06-01)Some laboratories and institutions use bare LR-115 polymer (cellulose nitrate + polyester) as a nuclear track detector for radon measurements. They detect alpha particles from radon and its progeny products in the cellulose nitrate layer, whether emitted from the so-called effective volume located in front of the cellulose nitrate layer. However, concentric rings were recorded on the etched LR-115 detector when the possibility of alpha registration was canceled, and the polyester was exposed to natural radiation in different configurations. Concentric rings were formed, apparently, due to the thermally induced self-defocusing effect. The outdoor causative agent can heat and change the refractive index of polyester, generating latent concentric rings. In this work, different configurations have been studied to find the outdoor causative agents and to clarify the possible physical causes. Furthermore, results show reproducibility and suggest that the ultraviolet radiation can cause concentric rings on the cellulose nitrate layer. - 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, Locating active faults in the Cusco Valley using magnetotelluric and radon gas data(RELX Group (Netherlands), 2024-01-01) - 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.