Microfabricated thermionic detector
AssigneeSandia Corporation
InventorsPatrick R. Lewis, Ronald P. Manginell, David R. Wheeler, Daniel E. Trudell
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Abstract
A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.
Claims17
A microfabricated thermionic detector, comprising:
- a microhotplate comprising
- a substrate having a suspended membrane formed thereon,
- a resistive heating element disposed on a surface of the suspended membrane, and
- a low work function material disposed on a surface of the suspended membrane exposed to a detection chamber to provide a thermionic source that generates negative ions from a sample gas comprising an electronegative function group;
- at least one gas inlet attached to the detection chamber for introduction of the sample gas thereinto;
- an exhaust gas outlet attached to the detection chamber for removal of decomposition products therefrom;
- and
- an ion collection electrode disposed in the detection chamber proximate the thermionic source, wherein the electrode is positively biased relative to the thermionic source and collects the negative ions generated by the sample gas reacting with the thermionic source when the suspended membrane is heated by the resistive heating element and a voltage is applied between the thermionic source and the electrode.
Dependencies are inferred from the claim text.