A method of recovering vaporized precursor material with a carrier gas in a multi-chamber solid precursor delivery assembly , the method comprising: delivering carrier gas to a multi-chamber solid precursor delivery assembly ; retaining carrier gas within headspace of a first precursor chamber of the multi-chamber solid precursor delivery assembly generally above precursor material disposed within the first precursor chamber until a pressure differential of about 0.5 percent to about 50 percent of the average pressure in the first precursor chamber exists across a first porous distributor plate of the multi-chamber solid precursor delivery assembly separating the first precursor chamber from a second precursor chamber , at which time the carrier gas and vaporized precursor material recovered by the carrier gas flows through the first porous distributor plate to the second precursor chamber ; retaining the carrier gas within headspace of the second precursor chamber of the multi-chamber solid precursor delivery assembly generally above precursor material disposed within the second precursor chamber until a pressure differential of about 0.5 percent to about 50 percent of the average pressure in the second precursor chamber exists across a second porous distributor plate of the multi-chamber solid precursor delivery assembly separating the second precursor chamber from a third chamber, at which time the carrier gas and vaporized precursor material recovered by the carrier gas flows through the second porous distributor plate to the third chamber; and removing the carrier gas and vaporized precursor material recovered by the carrier gas from the multi-chamber solid precursor delivery assembly . delivering carrier gas to a multi-chamber solid precursor delivery assembly ; retaining carrier gas within headspace of a first precursor chamber of the multi-chamber solid precursor delivery assembly generally above precursor material disposed within the first precursor chamber until a pressure differential of about 0.5 percent to about 50 percent of the average pressure in the first precursor chamber exists across a first porous distributor plate of the multi-chamber solid precursor delivery assembly separating the first precursor chamber from a second precursor chamber , at which time the carrier gas and vaporized precursor material recovered by the carrier gas flows through the first porous distributor plate to the second precursor chamber ; retaining the carrier gas within headspace of the second precursor chamber of the multi-chamber solid precursor delivery assembly generally above precursor material disposed within the second precursor chamber until a pressure differential of about 0.5 percent to about 50 percent of the average pressure in the second precursor chamber exists across a second porous distributor plate of the multi-chamber solid precursor delivery assembly separating the second precursor chamber from a third chamber, at which time the carrier gas and vaporized precursor material recovered by the carrier gas flows through the second porous distributor plate to the third chamber; and removing the carrier gas and vaporized precursor material recovered by the carrier gas from the multi-chamber solid precursor delivery assembly . <EOS>