ANGULAR-DISTRIBUTION AND ENERGY SPREAD OF A LITHIUM LIQUID-METAL ION-SOURCE

For a lithium liquid metal ion source (LMIS) an especially high angula r intensity acid a low energy broadening is expected because of the lo w mass of lithium. For a Li LMIS the axial angular intensity and the F WHM of the energy distribution have been measured. The results have be en compared with the theoretical predictions and with experimental res ults for gallium, the metal most widely used in LMIS. A correlation be tween angular intensity and the energy broadening is found. The Li LMI S has a high angular intensity, especially at low currents, compared t o the Ga LMIS. The energy spread in the low-current range is 25% lower than for the Ga LMIS. With increasing emission current the rise of th e angular intensity as well as the energy broadening is smaller than f or the gallium source.