Alpha spectrometry as a tool for annual dose-rate determination in pottery and soil

Several techniques have been employed for determining the annual dose-rate of pottery and soil. None gives all the information needed and each shows advantages and limitations; hence, it is necessary to use more than one technique, both for completeness and for cross-checking the data. Alpha spectrometry performed with Frisch-type ionization chambers appears promising; its specification and practical limitations will be discussed. Spectra will be shown for a number of samples where such factors as U-Ra disequilibrium and Rn escape are clearly observed; the Th/U ratio can be quantitatively evaluated. Below 15 and 50 ppm of U and Th, respectively, problems of backgroundf seriously limit the possibilities of quantitative determinations. (author)