In an embodiment an ionization detector includes a gate-insulator-substrate electron-emission structure (GIS-EE) configured to emit low-energy electrons, a sample chamber configured for at least one gas to be detected, the sample chamber being adjacent to the GIS-EE and a measuring unit configured to detect and/or select charged particles, wherein the charged particles are due to the emitted electrons and/or comprise the emitted electrons.

This electron emitting element includes a lower electrode, a surface electrode facing the lower electrode, a resistance layer arranged between the lower electrode and the surface electrode, and an insulating layer arranged between the lower electrode and the surface electrode. The resistance layer is an insulating resin layer containing conductive fine particles in a dispersed state. The insulating layer has a peripheral region for defining the electron emission region, and an emission control region which is arranged so as to overlap the electron emission region defined by the peripheral region. The emission control region is configured by a line-shaped insulating layer, a plurality of dot-shaped insulating layers, or both a line-shaped insulating layer and a plurality of dot-shaped insulating layers. The percentage of an area that the emission control region represents within an area of an electron emission region defined by the peripheral region is 2% or more and 60% or less.

This electron emitting element includes a lower electrode, a surface electrode facing the lower electrode, a resistance layer arranged between the lower electrode and the surface electrode, and an insulating layer arranged between the lower electrode and the surface electrode. The resistance layer is an insulating resin layer containing conductive fine particles in a dispersed state. The insulating layer has a peripheral region for defining the electron emission region, and an emission control region which is arranged so as to overlap the electron emission region defined by the peripheral region. The emission control region is configured by a line-shaped insulating layer, a plurality of dot-shaped insulating layers, or both a line-shaped insulating layer and a plurality of dot-shaped insulating layers. The percentage of an area that the emission control region represents within an area of an electron emission region defined by the peripheral region is 2% or more and 60% or less.

An electron emitter structure includes an electron emission layer which is arranged to have a first side and a second side, and an electron accelerating structure which is arranged on the first side of the electron emission layer. The electron emission layer has a mixture of metals so as to be atmospherically stable. The electron accelerating structure has at least one electrode which is electrically insulated from the electron accelerating structure so as to form an acceleration path which allows electrons which are released from the electron emission layer to be selectively accelerated upon generation of an adjustable electric field. The acceleration path has a length l of from 10 nm to 1 ?m.

In an embodiment an ionization detector includes a gate-insulator-substrate electron-emission structure (GIS-EE) configured to emit low-energy electrons, a sample chamber configured for at least one gas to be detected, the sample chamber being adjacent to the GIS-EE and a measuring unit configured to detect and/or select charged particles, wherein the charged particles are due to the emitted electrons and/or comprise the emitted electrons.

The present disclosure relates to a field emission device that generates X-rays by emitting an electron beam, and an X-ray generating apparatus using the same, including a semiconductor substrate; a bottom electrode disposed below the semiconductor substrate; an insulating layer disposed above the semiconductor substrate; a gate electrode disposed on the insulating layer; and, a top electrode disposed on the gate electrode; wherein the gate electrode is composed of a material satisfying at least one of a first condition for work function, a second condition for Gibbs free energy of a redox reaction with the insulating layer, a third condition for sublimation energy, and a fourth condition for electron mean free path.