Filamentless operation of a high-power electron bombardment furnace used for refractory metals atom beam generation Available to Purchase

Filamentless operation of a 10 kW electron bombardment vacuum furnace in the temperature range 2000–3000 K is described. This novel mode of operation was useful in obtaining low magnetic field ambient around the furnace. This enabled us to carry out sensitive measurement of atomic properties of refractory metal atoms with the help of well-collimated neutral atomic beams. In this furnace, the necessary electron emission was derived from the innermost heat shield, which was coated with a low work-function metal and placed closer to the boat to attain high enough temperatures. The destabilizing effect of high degree of electrothermal feedback was effectively countered by using a nonlinear ballast consisting of a bank of tungsten lamps. The ionized fraction in the atomic beam was removed with the help of biased grids. This furnace has provided uninterrupted service to many users over the last few years.