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Search Publications by: Joseph T. Hodges (Fed)

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Displaying 76 - 100 of 106

Line Positions and Line Strengths for the 3

January 1, 2006
Author(s)
D C. Robie, Joseph T. Hodges
Several rotational lines in the S and Q branches (including the previously unobserved Q32 and Q33 lines) of the 3-0 electric quadrupole band of H2 have been detected by cavity ring-down spectroscopy. Line strengths were measured at densities between 2

High-Resolution Cavity Ring-Down Spectroscopy of H216O at 10687.36 cm-1

February 11, 2004
Author(s)
Joseph T. Hodges
We describe a frequency-stabilized cavity ring-down spectroscopy apparatus enabling high-resolution line shape measurements of water vapor. The measured line strength and broadening parameter for the H216O transition at 10687.36 cm-1 are compared to

Detection of Trace Water in Phosphine with Cavity Ring-down Spectroscopy

January 1, 2003
Author(s)
Susan Y. Lehman, Kristine A. Bertness, Joseph T. Hodges
Water is a detrimental impurity even at concentrations of 10 nmol/mol or less in source gases for compound semiconductor epitaxial growth. Oxygen complexes from water incorporation cause degraded luminescent efficiency and reduced minority carrier

Trace Water Detection in Phosphine by Cavity Ring-down Spectroscopy

January 1, 2003
Author(s)
Susan Y. Lehman, Kristine A. Bertness, Joseph T. Hodges
We are using cavity ring-down spectroscopy (CRDS) to measure concentrations of water in nitrogen and, for the first time to our knowledge, in phosphine. Water vapor concentrations have been measured in purified and unpurified phosphine, indicating a water

Trace water detection in semiconductor-grade phosphine gas

November 11, 2002
Author(s)
Kristine A. Bertness, Susan Y. Lehman, Joseph T. Hodges, H. H. Funke, Mark W. Raynor
We are applying cavity ring-down spectroscopy (CRDS) to measure water concentrations in nitrogen and, for the first time to our knowledge, in phosphine. Semiconductor-grade phosphine cylinders from different suppliers contained water in the several ppm

Referencing Dilution-Based Trace Humidity Generators to Primary Humidity Standards

June 1, 2001
Author(s)
Peter H. Huang, Gregory E. Scace, Joseph T. Hodges
We describe a technique for measuring the trace humidity level delivered by a permeationtube type moisture generator (PTMG). Amount fractions in the range 10 nmol/mol to 100 nmol/mol of H2O in N2 carrier gas were considered. The measurements are referenced

Uncertainty of the NIST Low Frost-Point Humidity Generator

June 1, 2001
Author(s)
Gregory E. Scace, Joseph T. Hodges
The NIST Low Frost-point Humidity Generator (LFPG) produces water vapor gas mixtures with mole fractions from approximately 5 nmol/mol to 4 mmol/mol for research, calibration of transfer standards, and testing and development of new humidity

Evanescent-Wave Cavity Ring-down Spectroscopy for Trace Water Detection

February 1, 2001
Author(s)
A C. Pipino, Joseph T. Hodges
We explore the use of evanescent wave cavity ring-down spectroscopy (EW-CRDS) for water detection through a signal-to-noise ratio analysis. Cavity ring-down spectroscopy (CRDS) is an emerging optical absorption technique that employs the mean photon decay

Pulsed, Single-Mode Cavity Ringdown Spectroscopy

June 1, 1999
Author(s)
Roger D. van Zee, Joseph T. Hodges, J P. Looney
This paper demonstrates an implementation of single mode cavity ring-down spectroscopy, using a pulse laser system, with near shot-noise limited sensitivity. The rationale for this approach is discussed, the experimental apparatus is described, and the