2. Electrons

2.1 Introduction

The electrons considered here are energetic (several tens of keV to several MeV). There are three main phenomena that lead to electron emission.

• The β ⁺ or β ^– decay occurs for nuclei with an excess (β ^- ) or deficit (β ⁺ ) of neutrons (compared to stable nuclei) and which regain a more stable state by converting a neutron into a proton (or vice versa). This reaction is accompanied by the emission of an electron β ^- (or a positron β ⁺ ) (conservation...