Hewlett-Packard Company

James J Sullivan

Bruce Douglas Quimby

Armand P Neukermans

Douglass McManigill

William P Kruger

The oxygen-selectivity of an atomic emission detection system is enhanced by introducing a carbon-containing, preferably non-oxygenated, gas as a portion of the reagent gas. In preferred embodiments, the reagent gas is nitrogen and/or hydrogen and up to about 50 volume percent of a C.sub.1 -C.sub.4 hydrocarbon gas.

Method and scavenger gas for the analysis of oxygen-containing

A microwave resonant cavity for a spectroscopic light source includes a housing having therein a chamber formed by side walls and a cylindrical outer wall. The side walls having aligned openings therethrough which are on the longitudinal axis of the outer wall. A refractory tube which is adapted to contain a gaseous plasma extends through the aligned openings and across the chamber in the housing. The portion of the side walls of the chamber adjacent the openings are closer together than the remaining portions of the side walls so that the chamber has a first portion around the refractory tube which is narrower than a second portion of the chamber around the first portion. A coupling loop is electrically coupled to a side wall of the chamber within the second portion of the chamber and is connector to a coaxial connector which extends through the outer wall of the housing to deliver microwave power to the chamber. This provides a resonant cavity in which the plasma formed in the refractory tube is very short for increased power and greater brightness of the plasma. This also provides a resonant cavity which requires no tuning and is more stable.

Microwave resonant cavity

A spectrometer including a source of light, a slit member along the path of the light emitted from the source, a holographic, concave grating in the path of the light passing through the slit member, and a photodetector in the path of the diffracted light reflected from the grating. The photodetector is positioned substantially along the portion of the primary horizontal focal curve of the grating where it is intersected three times by a vertical focal curve of the grating. The three intersections being on the same side of the normal vector to the grating and two of the intersecting points being the positions of the laser used to form the grating.

Spectrometer using concave holographic diffraction grating

A multi-element optical detector having a planar array of detector elements is focused at the focal plane of an optical spectrometer by placing the detector with the detecting surface of the array facing the optical spectrometer and being substantially perpendicular to the axis of the path of the light from the optical spectra to the focal plane. Relative movement is provided between the detector and the focal plane along said axis so that the detector array is placed at several different positions with respect to the focal plane. At each position the output values of the detector elements of the array are measured and the second difference of the output values is determined by the equation (-F1+2.times.F2-F3), where F1, F2, and F3 are the output values of three of the elements. The optical detector is placed at the position which provides the maximum value of the second difference, which is the position of the focal plane.

Apparatus and method for adjusting focus of a multi-element optical

The radio frequency powered gas discharge tube of an atomic emission detector is cooled with a flow of liquid, and means are provided for grounding points in the flow that are on opposite sides of the radio frequency field so as to reduce the amount of radio frequency energy escaping from the discharge tube in the liquid.

Water-cooled gas discharge detector

An electron capture detector in which a thermionic source such as a filament provides electrons for the reaction in a source chamber having a port that connects to a detection chamber having a collector. Guard gas is introduced into the source chamber and sample gas into the detection chamber, and an exhaust port is provided in the detection chamber.

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Newark, DE, United States of America

James J Sullivan