Invention:
The compressing ion-beam ion shutter developed at The University of Arizona is composed of a series of electrically charged screens. By varying the relative voltages on the screens, the flow of ions into the detector chamber is blocked or opened. When the shutter is first opened, ions accumulate between the screens. When the shutter voltage is changed, the accumulated ions are compressed in space and the ion beam approaching the shutter is simultaneously closed. By controlling, (i) the relative voltages and the timing for changing voltage on each screen in the ion shutter, and (ii) the electrical gradient in the detector chamber, The University of Arizona researcher has achieved an increase in sensitivity with ion mobility spectrometers.
Background:
With the increase in attention to security concerns over past few years, ion mobility spectrometers have become popular devices for rapid detection and identification of airborne toxins, volatile organics, explosives, and other materials. However, a drawback to these devices is the sensitivity with which they can measure these compounds. The lack of sensitivity of ion mobility spectrometers can be attributed in part to the current shutter designs. An increase in the sensitivity can be realized through the use of the compressing ion-beam shutters described in this invention.
Advantages:
- These compressing ion-beam shutters can provide an increase in the concentration of ions available in the spectrometers.
- Increased signal to noise ratio.
- Increased effective sensitivity to the material being detected.
Applications:
- Ion mobility spectrometers
- Material detection and identification
- Security and defense
- Industrial hygiene
- Air quality monitoring
Status: issued U.S. patent #7,538,320
