RESUMEN
The determination of radionuclide activity concentration requires a prior knowledge of the full-energy peak (FEP) efficiency at all photon energies for a given measuring geometry. This problem has been partially solved by using procedures based on Monte Carlo simulations, developed in order to complement the experimental calibration procedures used in gamma-ray measurements of environmental samples. The aim of this article is to apply GEANT4 simulation for calibration of two HPGe detectors, for measurement of liquid and soil-like samples in cylindrical geometry. The efficiencies obtained using a simulation were compared with experimental results, and applied to a realistic measurement. Measurement uncertainties for both simulation and experimental values were estimated in order to see whether the results of the realistic measurement fall within acceptable limits. The trueness of the result was checked using the known activity of the measured samples provided by IAEA.
Asunto(s)
Calibración/normas , Modelos Estadísticos , Monitoreo de Radiación/instrumentación , Monitoreo de Radiación/normas , Manejo de Especímenes/normas , Espectrometría gamma/instrumentación , Espectrometría gamma/normas , Algoritmos , Simulación por Computador , Diseño de Equipo , Análisis de Falla de Equipo , Rayos gamma , Internacionalidad , Método de Montecarlo , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Serbia , Programas InformáticosRESUMEN
Radon time-series analysis, based on the short-term indoor radon measurements performed worldwide, shows two main periodicity: daily and seasonal. The information obtained from time series of the measured radon values is the results of the complex radon dynamics that arises from the influence of the large number of different parameters (the state of the indoor atmosphere (temperature, pressure and relative humidity, aerosol concentration), the exchange rate between indoor and outdoor air and so on). In this paper we considered daily radon variability in the underground low-background laboratory in Belgrade, Serbia. The results are originated from the radon time-series analysis based on the 3 y of the continuous short-term indoor radon measurements. At the same time, we obtained the time series of the temperature, pressure and relative humidity in the laboratory. We also tried to find the correlation between different time series.
Asunto(s)
Radiación de Fondo , Monitoreo de Radiación , Contaminantes Radiactivos/análisis , Radón/análisis , Estaciones del Año , Humanos , Laboratorios , Medición de Riesgo , Serbia , Factores de TiempoRESUMEN
Measurements of radon concentration in the underground low-level laboratory in Belgrade, Serbia with a discrete sampling (T=2 h) have been performed. From July 2008 to July 2010, the time-series analysis was carried out. Also, the simultaneous measurements of meteorological parameters (temperature, atmospheric pressure and relative humidity) in the laboratory were done. The simultaneous monitoring of these parameters shows the correlation between temporal variations of radon concentration and meteorological parameters. Also, the radon time-series analysis has been used to study the possible correlation between the anomalous behaviour of the radon concentration and the local seismicity.
Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Monitoreo de Radiación , Radón/análisis , Humanos , Laboratorios , Serbia , Factores de TiempoRESUMEN
A simulation programme based on the Geant4 toolkit has been developed to simulate the coincident responses of a plastic scintillator and an HPGe detector to the cosmic-ray muons. The detectors are situated in a low-level underground laboratory (25 m.w.e). Primary positions, momentum directions and energies of the muons are sampled from the angular and energy distributions of the cosmic-ray muons at the shallow underground level. Obtained coincident spectra of both detectors are presented and discussed.