Determination of the diffusion coefficient and solubility of radon in plastics

A Method for Identification and Assessment of Radioxenon Plumes by Absorption in Polycarbonates

A method for the retrospective evaluation of the integrated activity concentration of ¹³³Xe during radioxenon plumes and the moment of the plume's center is proposed and explored by computer modeling. The concept is to use a specimen of polycarbonate material (a stack of Makrofol N foils of thickness 120 µm and 40 µm in 1 L non-hermetic Marinelly beaker) that is placed in the environment or in a controlled nuclear or radiopharmaceutical facility. On a regular basis or incidentally, the specimen may be retrieved and gamma spectrometry in two consecutive time intervals with durations of 8 h and 16 h is performed. To assess the performance of the method, ¹³³Xe plumes of various integrated activity concentrations and with a duration of up to 10 h are simulated and analyzed, assuming that the measurement starts with a delay of up to one day after the moment of the plume center. It is found that the deviation between the estimates by the method and their true values are within a few percent. Depending on the delay, events of integrated ¹³³Xe activity concentration 250-1000 Bq h m^-3 might be qualitatively identified. At levels >10,000 Bq h m^-3, the uncertainty of the quantitative estimates might be ≤10%.

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.

Partition Coefficients and Diffusion Lengths of 222Rn in Some Polymers at Different Temperatures

In this work, the partition coefficients K and diffusion lengths LD of radon in some polymers are experimentally determined for several temperatures in the range T = 5–31 °C. Some of the obtained values are compared to published data available for the given temperatures. It is shown that the temperature dependencies of the partition coefficients K(T), the diffusion lengths LD(T), and the permeabilities P(T) could be described analytically for the studied temperature range 5–31 °C. This allows estimation of these quantities in the given temperature range and quantitative description of the transport of radon in the studied polymers.

Measurement of absolute γ-ray emission probabilities in the decay of 227Ac in equilibrium with its progeny

The emission probabilities of γ rays produced in the ²²⁷Ac decay series were determined by high-resolution γ-ray spectrometry of sources with standardised activity. The sources were prepared quantitatively on glass discs by drop deposition of a solution with ²²⁷Ac in radioactive equilibrium with its daughter nuclides. Their activity was measured by a primary standardisation technique based on alpha-particle counting at a defined low solid angle. Four laboratories performed γ-ray spectrometry and derived absolute γ-ray intensities. Mean values were calculated and compared with literature data and the currently recommended evaluated data. New values on certain γ-ray emission probabilities are proposed.

Liquid scintillation counting of polycarbonates: a sensitive technique for measurement of activity concentration of some radioactive noble gases

This work explores the application of the liquid scintillation counting of polycarbonates for measurement of the activity concentration of radioactive noble gases. Results from experimental studies of the method are presented. Potential applications in the monitoring of radioactive noble gases are discussed.

Retrospective measurements of thoron and radon by CDs/DVDs: a model approach

An approach for retrospective measurements of thoron ((220)Rn) and radon ((222)Rn) by home-stored CDs/DVDs is proposed. It employs analysis of alpha tracks at two depths beneath the disk surface. The signal in the first one (69 µm) is due both to (220)Rn and (222)Rn, while the signal at the second (80 µm) is due only to (222)Rn. The second signal is used as to measure (222)Rn, as well as to determine and subtract 'the (222)Rn component' from the first signal. The remaining '(220)Rn component' is used to measure thoron. Numerical modelling is performed and the results show that simultaneous retrospective measurements of thoron and radon are possible over a wide range of environmental concentrations.