Carbon nanotube electron ionization sources

An ion source for use in a mass spectrometer, comprising:

• an ionization chamber comprising carbon nanotube bundles for emitting electron beams, wherein the carbon nanotube bundles are fixed on a conductive surface on a first wall of the ionization chamber;
• a sample inlet disposed on the ionization chamber for sample introduction;
• an ion-beam outlet disposed on the ionization chamber to provide an exit for ionized sample molecules;
• and
• at least one electrode disposed proximate the ion-beam outlet to focus the ionized sample molecules exiting the ionization chamber,
• wherein the conductive surface on the first wall and an electron-energy plate on a second wall of the ionization chamber are adapted to connect to an electrical source such that an electrical field is established to induce electron beam emission from the carbon nanotube bundles.

A mass spectrometer, comprising:

• a carbon nanotube-based ion source;
• an electron emitter assembly configured to emit electron beams, wherein the electron emitter assembly comprises carbon nanotube bundles fixed to a substrate for emitting the electron beams, a first control grid configured to control emission of the electron beams, and a second control grid configured to control energies of the electron beams,
• a mass filter operatively coupled to the carbon nanotube-based ion source for separating ionized sample molecules based on their mass-to-charge ratios;
• and
• an ion detector operatively coupled to the mass filter for detecting the ionized sample molecules.