A hemisphere accelerating electrode has a double structure composed of an inner accelerating electrode and an outer accelerating electrode. The ultrahigh molecular weight polyethylene portion has a textured surface with a pattern of ribs which may vary in shape and configuration, such as a series of parallel ribs or a plurality of pins of various cross-sectional shapes, e. In one embodiment, the microelectronic workpiece further includes a plurality of dies formed on the device side of the substrate, a dielectric layer over the dies, and a plurality of bond-pads on the dielectric layer. The motion detection mechanism is configured to compare the first video frame with the second video frame.