A chamber formed from an electrically conductive material is connected to a ground potential. A hot electrode formed from an electrically conductive material is disposed within the chamber in a substantially horizontal orientation and is physically separated from the chamber. The hot electrode includes a top surface defined to support a part to be measured. A radiofrequency (RF) transmission rod is connected to extend from a bottom surface of the hot electrode through an opening in a bottom of the chamber and be physically separated from the chamber. The RF transmission rod is defined to transmit RF power from a conductor plate in an electrical components housing to the hot electrode. An upper electrode formed from an electrically conductive material is disposed within the chamber in a substantially horizontal orientation. The upper electrode is electrically connected to the chamber and is defined to be movable in a vertical direction.