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Title: Method for improving instrument response

Abstract

This invention pertains generally to a method for improving the accuracy of particle analysis under conditions of discrete particle loading and particularly to a method for improving signal-to-noise ratio and instrument response in laser spark spectroscopic analysis of particulate emissions. Under conditions of low particle density loading (particles/m.sup.3) resulting from low overall metal concentrations and/or large particle size uniform sampling can not be guaranteed. The present invention discloses a technique for separating laser sparks that arise from sample particles from those that do not; that is, a process for systematically "gating" the instrument response arising from "sampled" particles from those responses which do not, is dislosed as a solution to his problem. The disclosed approach is based on random sampling combined with a conditional analysis of each pulse. A threshold value is determined for the ratio of the intensity of a spectral line for a given element to a baseline region. If the threshold value is exceeded, the pulse is classified as a "hit" and that data is collected and an average spectrum is generated from an arithmetic average of "hits". The true metal concentration is determined from the averaged spectrum.

Inventors:
 [1];  [2];  [3];  [4]
  1. 7528 Oxford Cir., Dublin, Alameda County, CA 94568
  2. 2665 Calle Alegre, Pleasanton, Alameda County, CA 94566
  3. 5443 Celeste Ave., Livermore, Alameda County, CA 94550
  4. 5447 Theresa Way, Livermore, Alameda County, CA 94550
Issue Date:
Research Org.:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
OSTI Identifier:
872993
Patent Number(s):
6061641
Assignee:
Hahn, David W. (7528 Oxford Cir., Dublin, Alameda County, CA 94568);Hencken, Kenneth R. (2665 Calle Alegre, Pleasanton, Alameda County, CA 94566);Johnsen, Howard A. (5443 Celeste Ave., Livermore, Alameda County, CA 94550);Flower, William L. (5447 Theresa Way, Livermore, Alameda County, CA 94550)
Patent Classifications (CPCs):
G - PHYSICS G01 - MEASURING G01J - MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; improving; instrument; response; pertains; accuracy; particle; analysis; conditions; discrete; loading; particularly; signal-to-noise; ratio; laser; spark; spectroscopic; particulate; emissions; density; particles; resulting; overall; metal; concentrations; size; uniform; sampling; guaranteed; discloses; technique; separating; sparks; arise; sample; process; systematically; gating; arising; sampled; responses; dislosed; solution; disclosed; approach; based; random; combined; conditional; pulse; threshold; value; determined; intensity; spectral; line; element; baseline; region; exceeded; classified; hit; data; collected; average; spectrum; generated; arithmetic; hits; true; concentration; averaged; particulate emissions; laser spark; threshold value; spectral line; spectroscopic analysis; signal-to-noise ratio; particle size; noise ratio; metal concentrations; particle analysis; metal concentration; particulate emission; size uniform; /702/356/

Citation Formats

Hahn, David W, Hencken, Kenneth R, Johnsen, Howard A, and Flower, William L. Method for improving instrument response. United States: N. p., 2000. Web.
Hahn, David W, Hencken, Kenneth R, Johnsen, Howard A, & Flower, William L. Method for improving instrument response. United States.
Hahn, David W, Hencken, Kenneth R, Johnsen, Howard A, and Flower, William L. Sat . "Method for improving instrument response". United States. https://www.osti.gov/servlets/purl/872993.
@article{osti_872993,
title = {Method for improving instrument response},
author = {Hahn, David W and Hencken, Kenneth R and Johnsen, Howard A and Flower, William L},
abstractNote = {This invention pertains generally to a method for improving the accuracy of particle analysis under conditions of discrete particle loading and particularly to a method for improving signal-to-noise ratio and instrument response in laser spark spectroscopic analysis of particulate emissions. Under conditions of low particle density loading (particles/m.sup.3) resulting from low overall metal concentrations and/or large particle size uniform sampling can not be guaranteed. The present invention discloses a technique for separating laser sparks that arise from sample particles from those that do not; that is, a process for systematically "gating" the instrument response arising from "sampled" particles from those responses which do not, is dislosed as a solution to his problem. The disclosed approach is based on random sampling combined with a conditional analysis of each pulse. A threshold value is determined for the ratio of the intensity of a spectral line for a given element to a baseline region. If the threshold value is exceeded, the pulse is classified as a "hit" and that data is collected and an average spectrum is generated from an arithmetic average of "hits". The true metal concentration is determined from the averaged spectrum.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {1}
}

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Works referenced in this record:

Real-time optical measurement of alkali species in air for jet engine corrosion testing
conference, February 2013