This radon emanation is a normal occurrence and thereby causes the terrestrial atmosphere to contain a low (~ 1 DPM/L = 1 disintegration per minute per litre) but fairly constant level of radioactive gas.After several days residence time in the atmosphere, the Rn-222 naturally decays to polonium-218, a metallic radionuclide which, over a period of hours/days, falls to the earth with dust and rain.
The dating of meteorites would then help Patterson in determining not only the age of these meteorites but also the age of Earth’s formation.
Particles emitted at these two energies can be identified using an alpha spectroscopy system.
The system consists of a surface barrier detector, preamplifier, amplifier, mixer router, analog to digital converter, multi-channel analyzer, and appropriate computer software.
Pb isotopes cannot exchange and secular equilibrium is achieved.
At secular equilibrium the activity of the parent isotope is equivalent to that of the daughter isotope.