supply 41 a discharge chamber 55 which can be made of carbon graphite insulation 46 e g stand off legs such as ceramic insulation that electrically insulates the discharge chamber 55 electrically conductive posts 47 that support the filament 48 which generates electrons and a solenoid 49 which provides a magnetic field to increase neutral collisions of the electrons produced by the filament 48 the solenoid rests on the base 54 which can be made of stainless steel the discharge chamber 55 is defined by the discharge chamber wall 45 and discharge chamber base 53 the crucible 44 is heated so that the material vaporizes after reaching its melting point or sublimation point continued heating results in the discharge chamber 45 to fill with vapor of the material 44 a in the crucible 44 the crucible 44 can be heated in a variety of ways for example a heating element can be applied to the crucible 44 to effect heating for example the crucible 44 which can be made of graphite can be embedded in a metallic heater such as a tantalum heater which functions to provide resistive heating the crucible 44 would be heated by the heat from the tantalum heater in this embodiment the crucible power supply connects to the heater alternatively the crucible 44 is heated with an electric current from the crucible power supply 41 through the electrically conductive supports 50 that attach to the crucible 44 either ac or dc can be used alternatively.