Device for separate radiometric determination of concentrations of radioactive elements

The paper concerns a device, made up of a combined detector and electronic unit, for selective radiometric determination of radioactive elements, for example equilibrium uranium and thorium, in samples. The purpose is to ensure separative recording of pulses from beta- and alpha-particles in a specified sequence of β-α coincidences delayed within non-overlapping time intervals, when measuring samples in layers of any thickness. The device uses a detector transparent to external luminescence emission, placed in a case with a mobile light-blocking system, and made of a β-scintillator light conductor bearing a layer of an α-phosphor. It is designed for analyses of rock and ore samples, and of the products resulting from their processing, in both field and laboratory conditions. In summary the method consists in mesuring the activity of the samples and in measuring β-α delayed coincidences