In-line cell for absorption spectroscopy
AssigneeAmerican Air Liquide, Inc.
InventorsRonald S. Inman, James J. F. McAndrew
Life of this patent
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Abstract
Provided is a novel in-line cell useful in absorption spectroscopy. The cell includes a sample region, a light entry port and a light exit port being the same or separate ports. Each port is in communication with the sample region and contains a light transmissive window. A mirror having a light reflective surface faces the sample region, and a heater effective to heat the light reflective surface is provided. The cell can be used to determine the concentration of molecular gas impurities in a sample. Particular applicability is found in semiconductor processing.
Claims20
A method for performing an absorption spectroscopy measurement, comprising the steps of:
- providing an in-line cell, comprising a sample region, a light entry port and a light exit port being the same or separate ports, each said port being in communication with the sample region and containing a light transmissive window, a mirror having a light reflective surface facing the sample region, and a heater effective to heat the light reflective surface of the mirror;
- and
- heating the light reflective surface to a temperature higher than that of other surfaces of the cell.
A method for performing an absorption spectroscopy measurement, comprising the steps of:
- providing an in-line cell, comprising a sample region, a light entry port and a light exit port being the same or separate ports, each said port being in communication with the sample region and containing a light transmissive window, a mirror having a light reflective surface facing the sample region, and a heater effective to heat the light reflective surface of the mirror;
- providing a light source for generating a light beam which passes through the light entry port into the cell, and a main detector for measuring the light beam exiting the cell through the light exit port;
- and
- heating the light reflective surface to a temperature higher than that of other surfaces of the cell.
A method for performing an absorption spectroscopy measurement, suitable for use in a semiconductor processing apparatus, comprising the steps of:
- providing a vacuum chamber in communication with a vacuum pump for evacuating the vacuum chamber;
- providing an in-line cell disposed between and in communication with the vacuum chamber and the vacuum pump, the cell comprising a sample region, a light entry port and a light exit port being the same or separate ports, each said port being in communication with the sample region and containing a light transmissive window, a mirror having a light reflective surface facing the sample region, and a heater effective to heat the light reflective surface of the mirror;
- providing a light source for generating a light beam which passes through the light entry port into the cell, and a main detector for measuring the light beam exiting the cell through the light exit port;
- and
- heating the light reflective surface to a temperature higher than that of other surfaces of the cell.
Dependencies are inferred from the claim text.