Two piece electrode assembly with gap for plasma control

An apparatus for distributing plasma products includes first and second electrodes that each include planar surfaces. The first electrode forms first apertures from a first planar surface to a second planar surface; the second electrode forms second apertures from the third planar surface to the fourth planar surface. The electrodes couple through one or more adjustable couplers such that the third planar surface is disposed adjacent to the second planar surface with a gap therebetween, the gap having a gap distance. Each of the adjustable couplers has a range of adjustment. The first and second apertures are arranged such that for at least one position within the ranges of adjustment, none of the first apertures aligns with any of the second apertures to form an open straight-line path extending through both the first and second electrodes.