A pneumatic paintball marker has, for example, a sleeve that controls the passage of air through the longitudinal barrel or opening within the marker. According to the present invention, the nucleic acid enzyme has an RNA-cleaving activity by which harmful cells such as infected or cancerated cells can be killed selectively and efficiently. The first positive meniscus lens has a concave lens surface facing toward a concave lens surface of the negative meniscus lens. Accordingly, the primary X-rays do not pass through a space between the target members, and are irradiated only at the target surfaces of the target members. The heat transfer plate having independently controllable gas volumes which may be pressurized to locally control thermal conductance between a heater member and a cooling member such that uniform temperatures may be established on a plasma exposed surface of the showerhead electrode assembly.