Determination of intense electron beam quality by Thomson-scattering

The aim of this paper is to present an experiment in progress. The experiment is an incoherent Thomson-scattering diagnostic applied on a relativistic electron beam. As a diagnostic, the Thomson scattering appears as a very powerful tool for the determination of the electron energy spread as a function of time and space for intense electron beams used for example in Collective Free Electron Laser (CFEL) experiments. Although the experimental setup is rather tedious to implement, the diagnostic is very important for CFEL studies as well as other microwave generation experiments. Similar experiments are now in progress in various laboratories^1,2. The particular experiment presented here is characterized by (i) the use of a short - pulse neodymium (3 Joules, 3 ns) as probe light beam and (ii) the low current density of the electron beam (1 MV, 1 kA/cm²).