Liquid metal ion source and method for measuring flow impedance of liquid metal ion source

A flow impedance measuring method for a liquid metal ion source, using an extraction electrode and a suppression electrode, for extracting metal ions from a liquid metal coating on a tip of an emitter electrode by generating a focused electric field at the tip of the emitter electrode, the method comprising:

• a storage process for inputting and storing a function defining a relationship between an amount of variation (ΔIe) in current of the emitter electrode and an amount of variation (ΔVsup) in the voltage of the suppression electrode as a function ΔIe=f(ΔVsup), with the voltage (Vext) of the extraction electrode being fixed;
• a detection process for detecting an amount of variation ΔVsup in the voltage (Vsup) of the suppression electrode when the voltage Vext of the extraction electrode is made to vary by only ΔVext with the current of the emitter electrode being fixed;
• and
• a calculation process for calculating flow impedance ΔVext/ΔIe using the voltage variation amounts ΔVext and ΔVsup acquired through the detection process and the function acquired through the storage process.

A liquid metal ion source comprising:

• an emitter electrode for emitting ions;
• an extraction electrode arranged proximate the emitter electrode for generating a focused electric field at a tip of the emitter electrode;
• a suppression electrode arranged proximate the extraction electrode for adjusting the strength of the focused electric field generated at the tip of the emitter electrode so that metal ions are extracted from liquid metal covering the tip of the emitter electrode at a desired emission current value;
• a storage device for storing a function defining a relationship between variation (ΔIe) in current of the emitter electrode and variation (ΔVsup) in a voltage of the suppression electrode as a function ΔIe=F(ΔVsup), with the voltage (Vext) of the extraction electrode being at a fixed value;
• and a control apparatus for controlling voltages of the extraction and suppression electrodes and the emission current, detecting the variation ΔVsup in the voltage (Vsup) of the suppression electrode when a voltage (Vext) of the extraction electrode is made to vary by only ΔVext with the current of the emitter electrode being held to a fixed value, and calculating flow impedance ΔVext/ΔIe using the voltage variation amounts ΔVext and ΔVsup and the function acquired from the storage device.