Development of TL instruments for simultaneous radon and radon daughter monitoring

In order to extend the possibilities of environmental monitoring, three integrating instruments of different sensitivity and complexity and all using TLD, for simultaneous measurements of radon and radon daughters in air, were designed and tested. A small and very simple passive instrument has a sensitivity enabling one-month measurements to be performed around areas with an elevated radon level. A second, electrically polarised, passive instrument has a sensitivity four times higher than the previous one. A larger active-passive instrument of high sensitivity gives a clear TL signal even after a 24 hour exposure at average environmental concentrations. In all three instruments, thin CsSO4:Dy teflon discs are used, giving the highest response and stability. The first two types of instruments are promising and are now under further study before routine application. Ten instruments of the third type have shown excellent reliability and reproducibility of response and are now being used for surveying the Krakow district. (author)