A compact thermal lithium-beam source using a solid Al/Li alloy for Li sublimation

Abstract

Thermal lithium beams are widely used in physics for different purposes. To overcome certain disadvantages of conventional liquid-lithium ovens concerning handling, conditioning, and lifetime of the Li filling, a solid Li-evaporation device was constructed. An aluminum-based alloy, which contains about 9 at. % of lithium, is employed. The oven can easily be mounted in any position, and Li atoms can be injected in any desired direction. The parameters of the beam (axial and radial flux profiles) have been measured as a function of temperature and time. At a distance of 100 mm from the oven, Li flux densities of more than 2×1014 cm−2 s−1 have been achieved, lasting for more than 16 days of continued operation. The full beam divergence at half maximum is 8°. As a typical application of the device in plasma diagnostics, radial electron density profiles have been measured in the scrape-off layer of the TEXTOR tokamak.