The invention discloses a tuneable resonator with a substrate layer, which substrate layer supports a structure with a first electrode. The ink channel has a valve accommodation room and a valve opening formed in a wall surface located at one end of the valve accommodation room. Following breakdown, a sequence of one or more lower voltage and lower current pulses is applied to said electrodes, with a low \u201csimmer\u201d current being sustained through the plasma between pulses, preventing total plasma recombination and allowing the plasma kernel to move toward a free end of the electrodes with each pulse. The instrument is tilted with respect to a central axis of the bone plate hole to an angle wherein the gauge element remains at or below the outwardly facing surface of the bone plate adjacent the counterbore.