Raytheon Company

He Holdings, Inc.

J Brian Murphy

Carl W Townsend

Clifford A Megerle

John McHardy

John M Brauninger

An ion mobility spectrometer includes a housing with a flow channel, an air pump to force air through the flow channel, a heater at an inlet end of the flow channel, and an ionization source that ionizes the air after it is heated. The heated, ionized air passes through an electric field produced by a field source and a plurality of sensor elements located within in the wall of the flow channel in the measurement region of the electric field. The sensor elements include a plurality of sensor electrodes in one wall of the flow channel. Ion currents to the sensor electrodes are measured by an integrated high-sensitivity readout circuit array, permitting the sensor electrodes to be quite small. The sensor electrodes may be arranged in one-dimensional or two-dimensional arrays.

Miniature ion mobility spectrometer

The composition of an electrically conductive mixture, such as a mixture of gasoline and alcohol, is measured using a single measurement cell having a first electrode and a second electrode with a measurement space therebetween for receiving a specimen of the mixture. With a specimen of the mixture in the measurement space, the first electrode is alternatively connected to a reference discharge voltage, preferably ground, and to an applied voltage through a resistor. A first operational state encompasses the period when the first electrode is connected to the reference discharge voltage and a second operational state encompasses the period when the first electrode is connected to the applied voltage through the resistor. A first operational state peak voltage is measured during the first operational state, and a second operational state peak voltage is measured during the second operational state. The first operational state peak voltage and a preselected constant proper fraction of the second operational state peak voltage are summed to obtain a summed voltage output, which may be correlated to the composition of the mixture.

Dielectric mixture composition sensor with compensation for mixture

The composition of an electrically conductive mixture, preferably a mixture of gasoline and alcohol, is measured using a single measurement cell having a first electrode and a second electrode with a measurement space therebetween for receiving a specimen of the mixture. With a specimen of the mixture in the measurement space, the first electrode is alternatively connected to a reference discharge voltage, preferably ground, and to a feedback control voltage. A first operational state encompasses the period when the first electrode is connected to the reference discharge voltage and a second operational state encompasses the period when the first electrode is connected to the feedback control voltage. A first operational state peak voltage is measured during the first operational state, and a peak second operational state voltage is measured during the second operational state. The first operational state voltage and a preselected constant proper fraction of the peak second operational state voltage are mathematically combined to obtain a voltage output, which may be correlated to the composition of the mixture. The voltage output is also used as the feedback control voltage, to produce a linear signal output as a function of dielectric constant of the conductive mixture.

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Culver City, CA, United States of America

J Brian Murphy