Patent ID: 7300684

Claim:
A method of applying material to internal surfaces of a conductive workpiece comprising: attaching anodes at openings of said conductive workpiece while maintaining electrical isolation of said anodes from said conductive workpiece, said openings including at least one entrance and at least one exit; connecting a biasing system such that said conductive workpiece functions as a cathode; coupling a vacuum source to each said exit of said conductive workpiece; coupling a source of gas to each said entrance of said conductive workpiece to introduce a gas that includes said material to be applied for formation with said conductive workpiece, wherein coupling said vacuum source includes pumping said interior of said conductive workpiece to a low pressure prior to introducing said gas so as to create a stable pressure within said interior, said biasing system being configured to apply a voltage bias between said conductive workpiece and said anodes such that a plasma is generated within said interior; and regulating said source of gas and said vacuum source such that pressure within said interior remains related to an interior diameter of said conductive workpiece so as to maintain a condition in which plasma intensity within said interior is adjustable via variations of said biasing system, wherein said condition establishes a hollow cathode effect.