1. Gas detectors

1.1 Introduction

Gas detectors can be classified into three main families according to the value of their internal gain G :

• the ionization chamber (IC; G = 1);

• the proportional counter (CP; G " 10 ² to 10 ⁵ ) ;

• Geiger-Müller counter (GM; G " 10 ⁶ to 10 ⁸ ).

Figure 1 shows the evolution of signal amplitude...