An electrode support structure assembly (12, 12'), comprising: a plug defining a longitudinal axis and configured to connect to a fluid delivery line, the plug comprising: (i) a lumen configured to receive a fluid from the fluid delivery line, the lumen extending in an axial direction and comprising an axial distal end; and (ii) a distal tip adjacent to the axial distal end of the lumen and comprising a first channel (90, 92) extending across the distal tip; a cap disposed around at least a portion of the plug, the cap comprising: (i) a first wall extending in the axial direction and comprising a plurality of apertures (118a 1 -d 2); and (ii) a second wall extending inwardly from the first wall in a radial direction, the first wall and the second wall defining an interior into which the distal tip of the plug is disposed; and a plurality of support members (30a - d), each support member (30a - d) comprising a distal portion at least partially disposed in the interior of the cap such that the cap is configured to constrain relative movement of the distal portions of the plurality of support members (30a - d) with respect to the cap, wherein the first channel (90, 92) of the plug and at least one of the plurality of support members (30a-d) are configured to direct the fluid outwardly in a radial direction after exiting the lumen of the plug. a plug defining a longitudinal axis and configured to connect to a fluid delivery line, the plug comprising: (i) a lumen configured to receive a fluid from the fluid delivery line, the lumen extending in an axial direction and comprising an axial distal end; and (ii) a distal tip adjacent to the axial distal end of the lumen and comprising a first channel (90, 92) extending across the distal tip; (i) a lumen configured to receive a fluid from the fluid delivery line, the lumen extending in an axial direction and comprising an axial distal end; and (ii) a distal tip adjacent to the axial distal end of the lumen and comprising a first channel (90, 92) extending across the distal tip; a cap disposed around at least a portion of the plug, the cap comprising: (i) a first wall extending in the axial direction and comprising a plurality of apertures (118a 1 -d 2); and (ii) a second wall extending inwardly from the first wall in a radial direction, the first wall and the second wall defining an interior into which the distal tip of the plug is disposed; and (i) a first wall extending in the axial direction and comprising a plurality of apertures (118a 1 -d 2); and (ii) a second wall extending inwardly from the first wall in a radial direction, the first wall and the second wall defining an interior into which the distal tip of the plug is disposed; and a plurality of support members (30a - d), each support member (30a - d) comprising a distal portion at least partially disposed in the interior of the cap such that the cap is configured to constrain relative movement of the distal portions of the plurality of support members (30a - d) with respect to the cap, wherein the first channel (90, 92) of the plug and at least one of the plurality of support members (30a-d) are configured to direct the fluid outwardly in a radial direction after exiting the lumen of the plug.