Use of one or more retro-reflectors in a gas analyzer system
AssigneeMKS Instruments, Inc.
InventorRobert M. Carangelo
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for monitoring at least one gas in a sample gas. An exemplary system includes a source used for generating a beam of radiation, at least one retro-reflector configured to receive the beam of radiation from the source in an incident direction and reflect the beam of radiation toward the source in alignment with the incident direction, and a motor configured to move the at least one retro-reflector with respect to the source in a direction collinear with the incident direction. The system also includes a sample cell storing a sample gas comprising at least one gas. The sample cell is configured to allow at least a portion of an extracted beam of radiation from a cavity, defined by the source and the at least one retro-reflector, to propagate therethrough.
Claims26
A system for monitoring at least one gas in a sample gas, the system comprising:
- a source for generating a beam of radiation;
- at least one retro-reflector configured to receive the beam of radiation from the source in an incident direction and reflect the beam of radiation toward the source in alignment with the incident direction, thereby causing radiation in a cavity defined by the source and the at least one retro-reflector to obtain a desired wavelength;
- a motor configured to move the at least one retro-reflector with respect to the source in a direction collinear with the incident direction;
- a sample cell storing the sample gas comprising the at least one gas;
- a beam splitter located external to the cavity, the beam splitter configured to split the at least a portion of the extracted beam of radiation into at least (i) a first beam of radiation directed through the sample cell and (ii) a second beam of radiation directed through a reference path;
- a recombination device for interfering and recombining the first beam of radiation after traversing through the sample cell with the second beam of radiation to generate a first recombined beam of radiation;
- a detector in optical communication with the sample cell, wherein the detector is configured to generate a first recombined signal at the output of the sample cell based on the first recombined beam of radiation;
- and
- a processor, in electrical communication with the detector, configured to determine a concentration of the at least one gas in the sample gas based on a phase difference between the first recombined signal and a second recombined signal.
A method for monitoring at least one gas in a sample gas, the method comprising:
- generating a beam of radiation;
- directing the beam of radiation to at least one retro-reflector along an incident direction within a cavity defined by the source and the at least one retro-reflector;
- reflecting the beam of radiation by the at least one retro-reflector toward the source in a direction aligned with the incident direction, thereby causing radiation in the cavity to obtain a desired wavelength;
- splitting the extracted beam of radiation into at least a first beam of radiation and a second beam of radiation;
- directing the first beam of radiation from the cavity to propagate through a sample cell that stores the sample gas comprising the at least one gas;
- directing the second beam of radiation through a reference path containing a reference gas;
- interfering and combining the first beam of radiation and the second beam of radiation to generate a first recombined beam of radiation;
- determining a concentration of the at least one gas in the sample gas based on a phase difference of the first recombined beam of radiation and a second recombined beam of radiation;
- and
- modulating a wavelength of the radiation in the cavity to obtain the desired wavelength, wherein modulating the wavelength comprises at least one of adjusting a current or voltage for generating the beam of radiation or moving the at least one retro-reflector by a distance collinear to the incident direction.
Dependencies are inferred from the claim text.