Delivering particulate material to a vaporization zone

A method for vaporizing particulate materials and condensing them onto a surface to form a layer provides a quantity of particulate material in a first container (50) having an opening, dimensioned to allow free flow of the particulate material through the opening. The particulate material is transferred through the opening to a first feeding path (260), preconditioning the particulate material in the first feeding path and transforming the preconditioned particulate material from the first feeding path and feeding it along a second feeding path (265) to a vaporization zone.