Introduction

Chapter 1 introduced basic properties of radioactivity, including radio-activation processes and criteria for nuclear stability. Two other subjects necessary when applying radioactivity will be introduced in this chapter: units and standards employed for radioactivity measurements and radiation do simetry, and an introduction to rules and procedures developed to permit radiation applications to be carried out safely and efficiently with adequate protection from potentially harmful effects due to ionising radiations.

Appendix 2 at the end of this book lists publications carrying comprehensive information on health physics and radiation protection; these could be consulted if and when in doubt about safe operating conditions. The comments in this chapter and elsewhere in this book can cover no more than a small part of a large subject.

Units and standards of radioactivity

A summary of their characteristics

The consistency of results of physical measurements made in different locations depends on the consistency of the units employed for this purpose. All industrialised countries have passed laws accepting an international system of metric units for physical measurements known as Système International (SI) (BIPM, 1985) along with provisions for monitoring the coherence of these units by standards established in national and international standards laboratories. These laboratories cooperate around the globe to ensure that the units employed in their respective countries (see Section 2.3.2 below) are identical in size with those used in other countries, an essential activity because units for physical measurements have high industrial and commercial as well as scientific importance.