A method produces high-purity water from low-purity water, which is not limited to seawater but includes sewage. The second substrate is formed of a metal substrate, of which a setting surface provided with the electron sources is covered by an insulating layer. In a preferred embodiment, an entrance of the filament path is configured to seal to an exit orifice of a cassette containing the material supply, and an exit of the filament path is vented to release exhaust gas. Another device may then receive the license and process the one or more usage restrictions prior to presentation of the content asset to a user.