Abstract: A method of generating a desired gas is provided. The method includes introducing a matrix comprising media containing a parent compound and an inert media into an effusion tube comprising a first zone and a second zone. The first zone includes a micro-porous metal tube, and a closed end. The second zone includes a non-porous metal tube, and an open end. Heating the effusion tube, produces a desired gas.

Abstract: An apparatus for generating a desired gas is provided. The apparatus includes an effusion tube comprising a first zone and a second zone. The first zone includes walls of micro-porous metal tube, and a closed end. The second zone includes non-porous metal tube, and an open end. The two-zone effusion tube is fixtured inside of a larger cylindrical metal jacket with gas entry and exit ports at opposite ends of the jacket, which allows gas to flow over the exterior of the effusion tube. The effusion tube is configured to contain a matrix comprising media containing a parent compound and an inert media. A heating means for heating the effusion tube, thereby producing a desired gas which exits the open end of the metal jacket.