[en] The Catalan Environmental Radiological Surveillance Network consists of different types of scintillation gamma spectrometry detectors for the continuous and real-time automatic measurement of environmental radiation. The Network has a total of 35 monitors that obtain spectra every 10 minutes: 23 direct measurement monitors (13 with LaBr3(Ce), 5 SrI2(Eu) and 5 NaI (Tl) detectors), 10 particulate filter monitors (9 with LaBr3(Ce) detectors and 1 with SrI2(Eu)) and 2 river water monitors. A method for the automatic and real-time quantification of the activity concentration of artificial, natural and NORM isotopes was developed and tested in the laboratory. The uncertainties in the activity concentrations, as well as the corresponding detection limits, were calculated applying the ISO-11929 standard. The developed and validated method that is exposed in the present study will be implemented shortly in all the stations of the Network. The method is based on the analysis by spectral regions or ROIs (Regions of Interest). The method eliminates from the ROIs of the artificial (or NORM) isotopes of study the contributions due to emissions of natural isotopes (overlapping and Compton radiation), the ambient background, the possible intrinsic background of the detector and the contributions of other possible isotopes. As a result, an equation is generated for each isotope that allows us to obtain its net activity concentration (Bq/m3). This procedure is applied to determine the activity concentration of isotopes of natural origin (212Pb, 214Pb and 214Bi), artificial (131I, 137Cs and 60Co) and NORM (234Th). The method successfully eliminates the contribution of natural elements, intrinsic background and Compton contribution, both in situations with high and low activity of natural isotopes. Therefore, it allows obtaining the net activity concentration of the artificial isotopes of interest and eliminates the presence of false positives that could be produced by the presence of natural isotopes.

[en] This study describes the equipment implementation of a mobile gamma spectrometry unit using LaBr3 detectors and the process followed to obtain a radiological map of Catalonia (Spain). The mobile unit consists of two 2”x2” LaBr3 scintillation detectors mounted on the top of a 4x4 car. To obtain the preliminary map, the extension of Catalonia was divided in 1425 cells of 5x5 km2. Before starting the measurements, we planned a route to ensure a proper distribution and a minimum quantity of spectra within each cell. The car is equipped with a portable computer to control spectra acquisition and a GPS system that associates a position to each spectrum. Each spectrum is stabilised and calibrated. During the acquisition, the computer placed inside the car shows, in real-time, the value of the ambient dose equivalent and the exact location. Therefore, when the software obtains an unexpected high value, the driver of the car can modify the route to acquire more spectra of the area. The first data set of measurements included 70000 spectra obtained during stable weather conditions and represent the preliminary results of the radiological map, as other data campaigns are currently under preparation. In this study, we present the ambient dose equivalent map of Catalonia and isotopic information of interest, such as punctual detections of 137Cs and 131I and other radionuclides. The origin of these detections is analysed and explained in detail.

[en] In this work, it is demonstrated that spectrometric equipment can be used to measure dose rates. Besides, an analysis method for spectrometric data obtained in short integration periods is proposed. The method basically consists in the study of the evolution of the number of counts in certain windows or regions of interest (ROIs) in gamma spectra. The ROIs are chosen strategically for its probability of containing counts coming from characteristic gamma emissions from certain isotopes of interest. The method is useful to set early warning criteria.

[en] The renewal of the automatic environmental radiation surveillance network of the Gereralitat of Catalunya has been carried out through the development and implementation of gamma-spectrometry-based equipment. The monitors use scintillation cristals, either NaI(Tl) or LaBr₃(Ce) and currently, there are 3 types of equipment: water radioactivity monitors, aerosols on a particulate filter monitors and direct measurement monitors. In this paper, we expose the basic features of its operation, the details of their calibration and the minimum detectable activity concentrations for some isotopes

[en] The renewal of the automatic environmental radiation surveillance network of the Generalitat of Catalunya has been carried out through the development and implementation of gamma-spectrometry-based equipment. the monitors use scintillation crystals, either Na(TI) or LaBr₃(Ce) and currently, there are 3 types of equipment water radioactivity monitors, aerosols on a particulate filter monitors and direct measurement monitors. In this paper, we expose the basic features of its operation, the details of their calibration and the minimum detectable activity concentration for some isotopes. (Author)

[en] This work describes a method of analysis to extract information radiation from gamma spectra obtained during short time intervals. Therefore, method allows to carry out an analysis of data in real time, which in turn, ensures that an early warning system can be established. (Author)

[en] In this paper, we describe the general aspects of the implementation of gamma spectrometry in water, as well as the development of two measuring devices based on this technique: aerosol monitor (RARM-F) and a monitor direct measurement (RARMD2) , both patent applications. Furthermore, they described in detail the aspects of calibration of equipment, which has been made by combining experimental measurements with Monte Carlo simulations. (Author)

[en] The optimization of the dose given in radiology scans, one of the three fundamental principles of radiation protection implies sufficiently precise knowledge of the dose distribution in organs with weighting factor for the calculation of effective dose in patients.

[en] Highlights: • A 2″ × 2″ LaBr₃(Ce) gamma-ray spectrometry water monitor is characterized. • Experimental energy and resolution calibrations are performed. • The detector efficiency is obtained by MC simulations with EGS5 code system. • Minimum detectable activity concentrations for ¹³¹I and ¹³⁷Cs are given. • A rainfall radiological increment is compared with the NaI(Tl) monitor. - Abstract: A scintillation gamma-ray spectrometry water monitor with a 2″ × 2″ LaBr₃(Ce) detector was characterized in this study. This monitor measures gamma-ray spectra of river water. Energy and resolution calibrations were performed experimentally, whereas the detector efficiency was determined using Monte Carlo simulations with EGS5 code system. Values of the minimum detectable activity concentrations for ¹³¹I and ¹³⁷Cs were calculated for different integration times. As an example of the monitor performance after calibration, a radiological increment during a rainfall episode was studied.

[en] This paper proposes an analysis methodology based on the spectral windows technique aimed for environmental real-time gamma-ray spectra obtained with scintillation detectors. The method permits us to monitor activity concentrations of selected isotopes, such as anthropogenic radionuclides like ¹³⁷Cs and ¹³¹I, by removing the Compton scattering plus other external contributions and resolving peak overlapping within any window. Activity concentrations are presented for ¹³⁷Cs, ¹³¹I, ²¹⁴Bi, and ²¹⁴Pb when applying the method to a monitor using a LaBr₃(Ce) detector. The method avoids false-positive and false-negative results of anthropogenic radionuclides in the presence of radiation from natural origins by obtaining activity concentrations that correspond to those obtained by a Gaussian fitting commercial software. (paper)