Attenuation of alpha particle track dose for spherical grains

For both thermoluminescence and electron spin resonance dating, it is now well established that the signal induced by alpha particles is not proportional to the energy deposited in a sample, but rather is approximately proportional to the total track length deposited. We present here the expected attenuation of the signal to a spherical grain due to alpha sources both external and internal to the grain. The effect of etching grains is also considered. For an unetched grain, the absorbed track dose due to a single alpha particle energy can be expressed in simple analytical form. These results update and extend the data presented by a previous author, which considered deposited energy rather than deposited track length. Because the density of deposition of alpha particle energy increases towards the end of the track, attenuation effects for a given size grain are greater than those presented previously. (author)