Abstract: An evaporator chamber has an entry end with a conduit connected to the output of a mass flow regulator, an exit end connected to a vacuum, and a wall surface extending therebetween. A body having capillary action is disposed in the chamber and has one end connected to the conduit and a free surface spaced from the wall surface in line of sight thereof. Heating means for the wall surface heats the body radiantly and causes monomer carried thereby to evaporate.