Performance level of an autonomous system of continuous monitoring of radioactivity in seawater

Determination of marine gamma activity and study of the minimum detectable activity (MDA) in 4pi geometry based on Monte Carlo simulation

“…Finally, the number of channels used to define the peak width, N, is proportional to the full width at half maximum (FWHM) of the detector. This linear dependence follows to a good approximation of the FWHM experimental study as a function of γ-ray energy, f (E), by fitting spectra of standard calibration point sources in the air (Tsabaris et al 2008).…”

“…In order to test the reliability of these simulations, experimental values (Tsabaris et al 2008) of the NaI(Tl) detector marine efficiency, ε m , (extracted for the 140.5-, 661.6-, and 1,460.6-keV transitions of 99m Tc, 137 Cs, and 40 K, respectively) were deduced and seem to be in good agreement with the simulated ones. The experimental and simulated marine efficiency values are shown in Table 1 and seem to agree within 10% uncertainty values.…”

“…It is an autonomous system with relatively low power consumption, operational on oceanographic buoys and seabed platforms. The design and special characteristics of the developed system are described elsewhere (Tsabaris et al 2008). The detection system had to be tested and calibrated in the laboratory, in a water tank, before its deployment in the marine environment.…”

“…Such crystals are contemporarily used in many oceanographic applications, using continuous measurements for radiation monitoring with buoy operation and in situ measurements in seawater (Aakenes 1995;Soukissian et al 1999;Wedekind et al 1999; Baranov et al 2003;Tsabaris and Ballas 2005;Osvath et al 2005). A lot of effort has been made during the past few years for the experimental calibration of detection systems in water tanks by diluting calibrated standard sources (Vojtyla 2001;van Put et al 2004;Tsabaris et al 2008).…”

Monte Carlo simulation of a NaI detector in the aquatic environment

“…Such crystals are contemporarily used in many oceanographic applications, using continuous measurements for radiation monitoring with buoy operation and in situ measurements in seawater [2][3][4][5][6]. A lot of effort has been made during the last years for the experimental calibration of detection systems in water tanks, by diluting calibrated standard sources [7][8][9].…”