[en] The results of JET, the large European Tokamak, are a large step into the achievement of the parameter domain which is necessary for a self-supporting fusion reaction. The product of central plasma density, central ion temperature and mean energy confinement time therefore has to raise a factor 25; In order to achieve the break-even point, a factor 5 is necessary. In a discharge, which is limited by a material limiter, the influx of impurities (limiter material) and the resulting purity degree of the plasma can be described according to physical laws of the SOL (Scrape-Off Layer)-plasma, in combination with sputtering. The simplest way to increase the purity is to operate at a as high as possible plasma density. Further improvements can only be obtained by applying other limiter materials or by resorting to an other configuration, e.g. the magnetic limiter. JET possesses a large and rather complete arsenal of diagnostics for studying the plasmawall interaction. (author). 17 figs

[en] In this paper the main principles of electron bombardment are discussed and an investigation is made of the most important factors which influence the emission and focussing of the electron source. Examples are given of the various types of electron guns which are developed for evaporation in vacuum, and the necessary accessories are mentioned. Furthermore, examples are discussed of various industrial applications of electron-beam evaporators. (Auth.)

[en] A Crossed Beam Reactor is an UHV apparatus in which reactions can be studied of solids with an incoming ion beam, a reactive gas beam, an UV laser beam or with combinations of two of these or with all three beams. From the outgoing reaction products the mass, kinetic energy and the exit direction can be measured. In this paper some aspects of the vacuum design and construction of the Crossed Beam Reactor are discussed, illustrated with some experimental results. (Auth.)