Beta doses to spherical grains

The classic paper of Mejdahl (1979) on beta doses to quartz grains has been a standard reference for many years. In this paper we present an update of the data for beta doses to spherical quartz grains from internal and external natural sources, using dose point kernels based on modem spectra and Monte Carlo calculations. The differences from the Mejdahl results are not large, reflecting the modest adjustments in nuclear data and in the physics of electron-photon cascades in recent decades. It is recommended that, for a grain of original diameter 100 pm which has had a 9 gm layer etched away, the typical attenuation factor should be approximately 0.92 rather than the traditional 0.90. In addition, theory and data for the effects of etching on the average beta dose are presented, and we outline procedures for the estimation of beta doses for any situation that can be modelled using a series of concentric uniform shells. (C) 2003 Elsevier Science Ltd. All rights reserved.