Determination of the Thorium Content of Rocks

摘要

A new method for the determination of thorium in quantities of the order of 10mdash;5to 10mdash;6g is employed to complete the data necessary for the calculation of the age of geological material. The alphahyphen;particle activity of thoron in a streaming gas is measured with a counter, a procedure which is shown to be superior to the usual ionization measurements on the thoron deposit. Simultaneously, the Pa/Ra ratio in common rocks can be determined.