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The "powder sandwich" method was adapted to the measuring equipment at the Laboratory of Radiometric Expertise, IFJ PAN (Kraków, Poland). The versatility of the method has been confirmed. The values of thoron emanation coefficients (f) for 16 materials have been determined. It has been found that the value of thoron emanation coefficient is not directly dependent on the concentration of 224Ra, other factors are also important, e.g. the size of the grains, the inter-grain space and the distribution of radium atoms in the grain. The influence of the grain size on the value of thoron emanation coefficient was investigated. [ABSTRACT FROM AUTHOR]

The radon activity concentration was measured in 67 rooms in kindergartens in Visegrad countries over a period of 1 year using the SSNTD method within the framework of the standard V4 project. In 7.5% of rooms radon activity concentration exceeded 300 Bq m−3, the reference value recommended by the Council Directive 2013/59/EURATOM. The annual effective doses due to radon inhalation ranged from 0.5 to 13.3 mSv for children and from 0.3 to 8.3 mSv for staff. [ABSTRACT FROM AUTHOR]

Radon measurements carried out in spas of V4 countries (Czech Republic, Hungary, Poland and Slovakia) are shown in this paper. The preliminary results showed that radon concentrations in spas are less than 400 Bq m in ca. 86 % of cases. However, radon concentration above 1000 Bq m was found. The paper presents the comparison of three types of passive radon detectors (RAMARN, Raduet and NRPB) used in this survey. The good consistency of results was found when indoor radon concentration was at a level from 80 to 400 Bq m. [ABSTRACT FROM AUTHOR]

The article presents new Polish probes SRDN-3, developed at the Institute of Nuclear Chemistry and Technology in Warsaw, equipped with a semi-conductor detector used for continuous measurements of Rn activity concentration. Due to a relatively high lower detection limit, the device is dedicated for use in underground spaces—caves, adits, mines, tourist routes in strongholds, pyramids, etc. Its structure allows for difficult conditions in which the device is transported to the measurement site, as well as hard operating conditions caused chiefly by large ambient relative humidity, reaching up to 100%. The authors present calibration results of these appliances, as well as the results of their work in a cave and an adit in the Sudetes (SW Poland). After almost 2 years of working in difficult conditions, the probes displayed high reliability. No defects of the semi-conductor detectors or the electronics were observed, which ensured problem-free communication of the probe-programmer-PC set. Thanks to this, the authors have a 2 year stock of data, recorded hourly by five probes, at their disposal. The only element that did not withstand the test of extreme operating conditions was one of the combined relative humidity and temperature sensors. No powering problems were observed either, and the batteries were replaced once a year, before the winter season. Also the programmer functioned faultlessly, enabling data transmission to a PC, which, being much more sensitive to operating conditions, had been placed away from the site of probe exposure. After using more sensitive temperature, relative humidity and pressure sensors, SRDN-3 probes will certainly prove an excellent tool for microclimate measurements (including measurement of air-atmosphere exchange) in caves and other underground sites. Even nowadays they are already a satisfactory tool for monitoring Rn concentration in underground spaces. [ABSTRACT FROM AUTHOR]