Photoinduced nucleation: a novel tool for detecting molecules in air at ultra-low concentrations
Abstract
A method and apparatus for determining the presence of molecules in a gas at concentrations of less than about 100 ppb. Light having wavelengths in the range from about 200 nm to about 350 nm is used to illuminate a flowing sample of the gas causing the molecules if present to form clusters. A mixture of the illuminated gas and a vapor is cooled until the vapor is supersaturated so that there is a small rate of homogeneous nucleation. The supersaturated vapor condenses on the clusters thus causing the clusters to grow to a size sufficient to be counted by light scattering and then the clusters are counted.
- Inventors:
-
- Baltimore, MD
- Masala, FI
- Bruchkoebel, DE
- New Market, MD
- Issue Date:
- Research Org.:
- Johns Hopkins Univ., Baltimore, MD (United States)
- OSTI Identifier:
- 874830
- Patent Number(s):
- 6469781
- Assignee:
- The United States of America as represented by the United States Department (Washington, DC)
- Patent Classifications (CPCs):
-
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- DOE Contract Number:
- FG02-95ER62004
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- photoinduced; nucleation; novel; tool; detecting; molecules; air; ultra-low; concentrations; method; apparatus; determining; presence; gas; 100; ppb; light; wavelengths; range; 200; nm; 350; illuminate; flowing; sample; causing; form; clusters; mixture; illuminated; vapor; cooled; supersaturated; rate; homogeneous; condenses; grow; size; sufficient; counted; scattering; light scattering; /356/
Citation Formats
Katz, Joseph L, Lihavainen, Heikki, Rudek, Markus M, and Salter, Brian C. Photoinduced nucleation: a novel tool for detecting molecules in air at ultra-low concentrations. United States: N. p., 2002.
Web.
Katz, Joseph L, Lihavainen, Heikki, Rudek, Markus M, & Salter, Brian C. Photoinduced nucleation: a novel tool for detecting molecules in air at ultra-low concentrations. United States.
Katz, Joseph L, Lihavainen, Heikki, Rudek, Markus M, and Salter, Brian C. Tue .
"Photoinduced nucleation: a novel tool for detecting molecules in air at ultra-low concentrations". United States. https://www.osti.gov/servlets/purl/874830.
@article{osti_874830,
title = {Photoinduced nucleation: a novel tool for detecting molecules in air at ultra-low concentrations},
author = {Katz, Joseph L and Lihavainen, Heikki and Rudek, Markus M and Salter, Brian C},
abstractNote = {A method and apparatus for determining the presence of molecules in a gas at concentrations of less than about 100 ppb. Light having wavelengths in the range from about 200 nm to about 350 nm is used to illuminate a flowing sample of the gas causing the molecules if present to form clusters. A mixture of the illuminated gas and a vapor is cooled until the vapor is supersaturated so that there is a small rate of homogeneous nucleation. The supersaturated vapor condenses on the clusters thus causing the clusters to grow to a size sufficient to be counted by light scattering and then the clusters are counted.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {1}
}
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