The parameters of the secondary electrons in the electron cooling system

The secondary electrons in an electron cooling system determine the current losses [1]. Their parameters depend on the collector efficiency. In this paper the behaviour of the secondary electrons in the LEAR electron cooler with S-shaped bending toroid magnets is examined. The second problem which takes place with secondary electrons is related to the generation of neutralised electron beams in an electron cooling system [2]. The generation of very dense neutralised beams is restricted by the beam-drift instability. This is a convective instability appearing in stationary conditions due to the feedback created by secondary electrons.