The measurement of the ambient dose equivalent H*(10) with automatic real-time radioactivity monitors using gamma-ray spectrometry provides valuable information at short integration times and serves as an alternative to conventional peak analysis of spectra. In this paper, a full methodology for the calculation of this quantity using Monte Carlo (MC) simulations is described and applied to real spectrometric measurements with LaBr(Ce) scintillation detectors. The methodology involves the calculation of the fluence-to-H*(10) conversion factors and a method for obtaining the fluence from gamma-ray spectra. The combination of these two elements makes it possible to calculate the H*(10). The obtained results are compared with the H*(10) measurements of a Geiger-Müller (GM) detector. Finally, the necessary activity concentration to produce a certain increment on the H*(10) is discussed for some isotopes. This is used to discuss the analysis capabilities of the spectrometric detectors when compared to GM ones.

No abstract

No abstract

<p>This study describes the equipment implementation of a mobile gamma spectrometry unit using LaBr<sub>3 </sub>detectors and the process followed to obtain a radiological map of Catalonia (Spain). The mobile unit consists of two 2”x2” LaBr<sub>3 </sub>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 km<sup>2</sup>. 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 <sup>137</sup>Cs and <sup>131</sup>I and other radionuclides. The origin of these detections is analysed and explained in detail.</p>

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 Cs andI, by removing the Compton scattering plus other external contributions and resolving peak overlapping within any window. Activity concentrations are presented for Cs,I, Bi, andPb when applying the method to a monitor using a LaBr(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.