Abstract: Apparatus for rapid cooling of blown tubular polymer films including a cryogenic flash chamber having a spray manifold from which a cryogenic fluid is sprayed toward molten polymer exiting from an annular die of an extruder. The sprayed cryogenic fluid quickly vaporizes and impacts the molten polymer to cool and solidify the polymer into a tube or bubble. A gas recirculating system driven by a blower is also utilized with an "air" ring at the base of the cryogenic flash chamber to initiate the cooling process. The cryogenic flash chamber is divided into two zones with independent temperature controls to produce films of different clarity and strength characteristics.