Field practices and techniques: introduction

Field measurements of beta particles for radiation protection are made at the surface of a (simulated) body; in contrast, gamma-ray measurements are made free-in-air. The standard instrument for beta measurements is the extrapolation chamber. Practical instruments may fail to match the extrapolation chamber's dependence on source direction or energy. Beta measurements often have to be made so close to the source that some way of correcting for instrument size is needed. This talk is intended to lay the groundwork for the session on field practices and techniques in beta-particle dosimetry. I will describe some of the major dosimetry problems and give general information about them, but specific solutions to the problems will appear in the papers during the sessions