  The use of double-faced, metallized, perforated PCB planes, segmented into
strips for the anodic read-out of ionization signals in liquid argon TPCs, is
emerging as a promising technology for charge readout in liquid argon TPCs used
in large volume detectors.As a proof of concept, a prototype liquid Argon TPC
hosting this new anode configuration based on single side perforated PCB planes
has been constructed and exposed to cosmic rays at LNL in Italy. Tests were
performed with both the metallized and insulating sides of the anode facing the
drift volume, providing the first evidence of the focusing effect on drift
electron trajectories through the PCB holes due to charge accumulation on the
insulator surface.
