Abstract
We have analyzed chemical compounds in environmental samples such as rock collected around radon hot springs and measured radium activities and radon emanation fractions of these samples. In previous studies, little attention was paid to some minerals of which the rock samples consist. In this study, the constituent minerals were first separated from the rock sampled at Badgastein in Austria and then measured the radium activity and the radon emanation fraction in order to clarify the radioactive characteristics of those minerals. The rock sample is fresh and composed of quartz (SiO2) and muscovite (KAl2(AlSi3)O10(OH)2). The two minerals were separated from the crushed rock sample (250500 m) using a high-density agent, sodium polytungstate solution (SPT). The radium activities and the radon emanation fractions of the mineral samples were determined as follows. Each sample of several tens of grams was put in a U-8 container, sealed with an epoxy resin adhesive and gamma rays (C1) of 214Pb from the sample were measured a high-purity germanium (HPGe) detector. After establishing the radioactive equilibrium among radium and its progeny (30 days), gamma rays (C2) of 214Pb from the sample were measured using the HPGe detector and then the radium activity in the sample was determined. The radon emanation fraction is expressed as (C2-C1)/C1. As a result, the separated samples were confirmed by X-ray diffraction to verify the proper separation of the minerals. The radium activity in the rock was 7 Bq/g. And, the radium activity of muscovite (10 Bq/g) was about 10 times higher than that of quartz (1 Bq/g). We similarly intend to discuss the radon emanation fractions of those samples.
