# US 9,753,013 B2 · Charged particle detector

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- Number: US 9,753,013 B2
- Document ID: US9753013B2
- Status: Granted
- Kind: B2
- Application number: 14/280,582
- Filed: 2014-05-17
- Published: 2015-01-08
- Granted: 2017-09-05
- Earliest claimed: 2013-05-18
- Assignees: Brechtel Manufacturing, Inc.
- Applicants: Brechtel Manufacturing, Inc.
- Inventors: Fredrick J Brechtel; David A. Horsley; Gerardo Jaramillo
- Web page: https://patentgrep.com/patent/US9753013B2

## CPC

- G01N 27/66: and measuring current or voltage
- G01N 27/624: Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS]
- G01R 29/24: Arrangements for measuring quantities of charge
- H01J 27/02: Ion sources; Ion guns {(for examination or processing discharge tubes H01J37/08; ion sources, ion guns for particle spectrometer or separator tubes H01J49/10; ion propulsion F03H1/00)}
- H01J 49/145: {using chemical ionisation}
- H01J 49/161: {using photoionisation, e.g. by laser}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

A system and method comprising a charger for ionizing aerosols; a spectrometer coupled to the charger and operable to select for a predetermined particle size; a porous charge collector coupled to the spectrometer, and a MEMS electrometer. In some embodiments the charge collector may be a metal frit electrically coupled to the electrometer. The electrometer may include a comb drive actuator coupled to a moving shuttle supported on flexures.

## Claims

### Claim 1

A system comprising:
a charger for ionizing aerosols;
a spectrometer coupled to the charger and operable to select for a predetermined particle size;
a charge collector coupled to the spectrometer, and
a microelectromechanical (MEMS) electrometer said electrometer coupled to the charge collector.

### Claim 2 (depends on 1)

The system of claim 1 wherein the charge collector is a porous metal frit electrically coupled to the electrometer.

### Claim 3 (depends on 1)

The system of claim 1 wherein the electrometer includes a moving shuttle supported on flexures.

### Claim 4 (depends on 1)

The system of claim 1 wherein the electrometer includes a comb drive actuator.

### Claim 5 (depends on 1)

The system of claim 1 further including either a cyclone or an impactor.

### Claim 6

A method including:
receiving an airflow, said airflow including an aerosol;
charging the aerosol within the airflow;
size-selecting a portion of the aerosol within the airflow, and
applying the size-selected aerosol portion to a MEMS electrometer.

### Claim 7 (depends on 6)

The method of claim 6 wherein the size-selecting is effectuated with a differential mobility analyzer.

### Claim 8 (depends on 6)

The method of claim 6 wherein the applying to a MEMS electrometer is effectuated using a porous, electrically isolated metal frit.

### Claim 9 (depends on 6)

The method of claim 6 wherein the size-selecting is effectuated using either a cyclone, or an impactor.

### Claim 10 (depends on 6)

The method of claim 6 wherein the size-selecting is effectuated using either a counterflow virtual impactor, a round jet impactor, or an electrostatic precipitator.

### Claim 11 (depends on 6)

The method of claim 6 wherein the electrometer includes a comb drive actuator.

### Claim 12 (depends on 6)

The method of claim 6 wherein the charger includes a plasma source.