Abstract: A gas ion gun includes an anode electrode to remove electrons from a gas in order to create gas ions. The anode electrode includes a wire made of an electrical conductive material or of a semiconductor material, the wire extending along a longitudinal axis from a proximal end to a flattened distal end. The anode electrode further includes a crystal particle directly deposited on the flattened distal end, the electrical conductivity of the crystal particle being ten times smaller than the electrical conductivity of the wire.

Abstract: A device for determining the electrical resistance of a system includes a field effect electron emitter capable of emitting electrons when the electrical emission potential Ve of the electron emitter is higher than a threshold value VL, with the emitting end of the emitter being at least partially conductive; an item of equipment capable of determining the electrical emission potential Ve of the electron emitter; a voltage source adapted to apply a potential difference E to the device and to generate an electric field at the emitter, an electron detector capable of detecting all or some of the electrons emitted by the electron emitter so as to measure the intensity of the current Imes flowing between the emitter and the detector; electrical connection means adapted to electrically connect the system and the device in such a way that the current intensity flowing between the emitter and the detector can also pass through the system.