A structure and method of formation. The thread mill includes a cylindrical main body having at least one spiral flute formed in an outer circumferential surface of the cylindrical main body, and at least one cutting edge each provided by a rear-side one of widthwise opposite edges, as viewed in the rotating direction, of a corresponding one of the at least one spiral flute. The simultaneous electrostatic confinement of electrons and magnetic confinement of ions avoids anomalous transport and facilitates classical containment of both electrons and ions. In some embodiments, the interrogation surface may have a particular shape that conforms to the shape of a target material. The electrically-insulating anvil is located on a support member attached to one or both of the third and fourth sealing members, and the anvil and support member are such that the anvil is spring mounted with respect to the third and fourth sealing members and such that the anvil can move within the recess by at least 0.