ABSTRACT
Generally lower temperatures of evaporation make most aspects of oven design easier than those discussed in Chapter 5 and included in this group are ovens for the production of beams of alkali metals and their salts. Some special techniques are, however, necessary to handle the alkali metals because of their reactivity with moist air, which increases with atomic number Z. One solution is to produce the beam by a reaction of stable substances in the oven and we begin the discussion of the alkali metals with those cases in Section 4.2. We then consider in Section 4.3 more conventional ovens where the material to be evaporated is loaded directly into the oven. In Section 4.4 we turn to the alkali halides, which have problems due to their corrosiveness in the liquid and vapour state. Ovens where an ampoule of material has to be broken are discussed in Section 4.5. Finally in this chapter we discuss recycling ovens, where material that is not formed into a useful beam is returned to the oven.
