A deposition source includes a crucible for containing deposition material and a body comprising a conductance channel. An input of the conductance channel is coupled to an output of the crucible. A heater heats the crucible so that the crucible evaporates the deposition material into the conductance channel. A heat shield comprising a plurality of heat resistant material layers is positioned around at least one of the heater and the body. A plurality of nozzles is coupled to an output of the conductance channel so that evaporated deposition material is transported from the crucible through the conductance channel to the plurality of nozzles where the evaporated deposition material is ejected from the plurality of nozzles to form a deposition flux.