In situ-force measurement for the determination of the evaporation rate with high-rate electron beam evaporation

A technique for the measurement of force at a water-cooled crucible during high rate electron beam evaporation is described. This technique has been used for the in situ measurement of the evaporation rate of titanium. With an electron beam power in the range of 30-150 kW an evaporation rate of 0.3-2.5 g s-1 was measured with this method. The force on the molten titanium surface caused by recoil and vapor pressure was measured to be 0.2-1.5 N. An additional force has been measured in the case of a spotless cathodic arc burning in the titanium vapor to achieve a high-rate plasma activated deposition.