Abstract: A semiconductor processing apparatus comprises a pyrophoric source vessel within an enclosure, the vessel containing a pyrophoric material. An air intake labyrinth extends away from the enclosure and has an inlet and an outlet. The inlet is in fluid communication with an exterior of the enclosure, and the outlet is in fluid communication with an interior of the enclosure. The labyrinth defines a tortuous path between the inlet and the outlet. In order to thermally isolate the enclosure, it can be surrounded by an air gap of at least 10 mm separating the enclosure from other components of the processing apparatus, to prevent damage to such other components. The thermal isolation can also be achieved by forming the enclosure from double walls with a 10 mm gap therebetween. The pyrophoric enclosure can have a separate exhaust duct and/or scrubber than those of a semiconductor processing reactor associated with the enclosure.