| CPC H05G 2/005 (2013.01) [H05G 2/008 (2013.01)] | 21 Claims | 

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               1. A system comprising: 
            a vacuum chamber; and 
                a rotating target assembly having an annular groove with a distal wall relative to an axis of rotation, wherein the rotating target is disposed in the vacuum chamber, and wherein the distal wall includes a porous region. 
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