The present invention relates generally to ion mobility spectrometers and sensors, and more particularly, to a miniaturized ion mobility sensor and spectrometer that may be used as a chemical sensor.
All known commercially available ion mobility spectrometers and sensors use isotopic ionization sources. One such ion mobility spectrometer is disclosed in U.S. Pat. No. 5,047,723 entitled "Method for Detection of Foreign Matter Contents in Gases", issued Sep. 10, 1991, for example. The assignee of this patent, Environics, Oy of Finland manufactures ion mobility spectrometers for use in detecting chemicals.
This patent discloses the use of an ionized carrier gas containing foreign matter that is passed through chambers with different electric fields. The foreign matter is ionized by the ions in the air, the ions are collected at electrodes in the chambers, and the ion currents passing through one or more chambers are measured, and corresponding signals are obtained. The amounts and relationships of these signals permit analysis of the foreign matter contained in the gasses. The ionization source disclosed in this patent is an isotopic ionization source wherein radioactive radiation derived from an Americium ionization source ionizes the carrier gas and the molecules of the foreign matter contained in it.
However, the ion mobility spectrometer manufactured by Environics, Oy, for example, is quite large. It would be advantageous to have an ion mobility spectrometer that is smaller in size than the large-sized spectrometers available from Environics, Oy, for example. It would also be advantageous to have an ion mobility spectrometer that performs as well as or better than other commercially available small-sized spectrometers, such as those made by Graseby, for example.
Accordingly, it is an objective of the present invention to provide for a miniaturized ion mobility spectrometer that may be used as a chemical sensor.