Preparation of multi-purpose radon emanation sources

The aim of this work was to prepare reference radon emanation sources traceable to primary standards to be used for radon-in-air as well as radon-in-water experiments. The feasibility of making stable radon emanation sources by drop deposition and chemisorption was studied. Experimental emanation coefficients for sources made by drop deposition and chemisorption ranged from 0.10 to 0.74 and from 0.18 to 0.25, respectively. These relatively low emanation coefficient values suggest that further method developments would be desirable. Proposals are made to improve chemisorption yield during source preparation and to obtain more accurate measurements on radon emanation coefficient.

Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

Exploratory monitoring of radon is conducted at one location in the deep underground Gran Sasso National Laboratory (LNGS). Measurements (15-min resolution) are performed over a time span of ca 600 days in the air of the surrounding calcareous country rock. Using both α - and γ -ray detectors, systematic and recurring radon signals are recorded. Two primary signal types are determined: (i) non-periodic multi-day (MD) signals lasting 2–10 days and (ii) daily radon (DR) signals—which are of a periodic nature exhibiting a primary 24-h cycle ( θ =0.48). The local ancillary environmental conditions (pressure, temperature) seem not to affect radon in air monitored at the site. Long-term patterns of daytime measurements are different from the pattern of night-time measurements indicating a day–night modulation of γ -radiation from radon in air. The phenomenology of the MD and DR signals is similar to situations encountered at other locations where radon is monitored with a high time resolution in geogas at upper crustal levels. In accordance with recent field and experimental results, it is suggested that a component of solar irradiance is affecting the radiation from radon in air, and this influence is further modulated by the diurnal rotation of the Earth. The occurrence of these radon signals in the 1 km deep low-radiation underground geological environment of LNGS provides new information on the time variation of the local radiation environment. The observations and results place the LNGS facility as a high-priority location for performing advanced investigations of these geophysical phenomena.

Influence of a component of solar irradiance on radon signals at 1 km depth, Gran Sasso, Italy

Exploratory monitoring of radon is conducted at one location at the deep underground Gran Sasso National Laboratory (LNGS). Measurements (15-min resolution) are performed over a time span of ca. 600 days in the air of the surrounding calcareous country rock. Utilizing both alpha and gamma-ray detectors systematic and recurring radon signals are recorded. Two primary signal types are determined: (a) non-periodic Multi-Day (MD) signals lasting 2–10 days, and (b) Daily Radon (DR) signals – which are of a periodic nature exhibiting a primary 24-h cycle. The local ancillary environmental conditions (P, T) seem not to affect radon in air monitored at the site. Long term patterns of day-time measurements are different from the pattern of night-time measurements indicating a day-night modulation of gamma radiation from radon in air. The phenomenology of the MD and DR signals is similar to situations encountered at other locations where radon is monitored with a high time resolution in geogas at upper crustal levels. In accordance with recent field and experimental results it is suggested that a components of solar irradiance is affecting the radiation from radon in air, and this influence is further modulated by the diurnal rotation of Earth. The occurrence of these radon signals in the 1 km deep low radiation underground geological environment of LNGS provides new information on the time variation of the local radiation environment. The observations and results place the LNGS facility as a high priority location for performing advanced investigations of these geophysical phenomena, due to its location and its infrastructure.