High pressure flow cell for spectral analyses and spectral range conversion

A spectroscopy system comprising:

• a flow cell having a longitudinal dimension, the flow cell comprising:
• an enclosure tube defining an interior, wherein the enclosure tube has opposed ends;
• a capillary waveguide extending along the longitudinal dimension through the interior of the enclosure tube, wherein the capillary waveguide has an outer surface defining an outer diameter, an inner bore defining an inner diameter, opposing first and second ends, and a length, wherein the capillary waveguide defines an inlet and an outlet to the inner bore, wherein the capillary waveguide has sufficient rigidity to remain optically straight when supported only by vertical forces at the opposing first and second ends of the capillary waveguide;
• and
• first and second compression fitting assemblies, wherein the first compression fitting assembly is coupled to the first end of the enclosure tube, wherein the second compression fitting assembly is coupled to the second end of the enclosure tube, and wherein each of the first and second compression fitting assemblies comprises a respective window at the respective first or second end of the capillary waveguide;
• a laser that is configured to provide a beam into the first end of the capillary waveguide;
• and
• a spectrometer that is configured to receive at least a portion of the beam from the second end of the capillary waveguide,
• wherein each respective compression fitting assembly of the first and second compression fitting assemblies comprises:
• an alignment fitting having a first end and an opposing second end and defining an interior bore proximate to the first end of the alignment fitting that is configured to receive an O-ring seal, wherein the interior bore at the first end of the alignment fitting defines a taper having a decreasing inner diameter in a direction away from the first end of the alignment fitting, wherein the alignment fitting is coupled to the enclosure tube via a first compression seal at the second end of the alignment fitting;
• a compression fitting that receives the second end of the alignment fitting, wherein the compression fitting is coupled to the alignment fitting via a second compression seal, wherein the respective window is received within the compression fitting;
• a nut threadedly engaging the compression fitting, wherein threaded engagement of the nut with the compression fitting causes a biasing force against the respective window;
• a first O-ring compressed between the compression fitting and the respective window;
• a compression sleeve at least partially received within the interior bore of the alignment fitting so that the respective window biases against the compression sleeve;
• and
• a second O-ring received within the interior bore of the alignment fitting and compressed between the compression sleeve and the alignment fitting.

A method comprising:

• providing a flow of gas through a spectroscopy system comprising:
• a flow cell having a longitudinal dimension, the flow cell comprising:
• an enclosure tube defining an interior, wherein the enclosure tube has opposed ends;
• a capillary waveguide extending along the longitudinal dimension through the interior of the enclosure tube, wherein the capillary waveguide has an outer surface defining an outer diameter, an inner bore defining an inner diameter, opposing first and second ends, and a length, wherein the capillary waveguide defines an inlet and an outlet to the inner bore, wherein the capillary waveguide has sufficient rigidity to remain optically straight when supported only by vertical forces at opposing ends;
• and
• first and second compression fitting assemblies, wherein the first compression fitting assembly is coupled to the first end of the enclosure tube, wherein the second compression fitting assembly is coupled to the second end of the enclosure tube, and wherein each of the first and second compression fitting assemblies comprises a respective window at the respective first or second end of the capillary waveguide;
• a laser that is configured to provide a beam into the first end of the capillary waveguide;
• and
• a spectrometer that is configured to receive at least a portion of the beam from the second end of the capillary waveguide;
• providing the beam from the light source through the inner bore of the capillary waveguide;
• and
• receiving at least a portion of the beam from the light source at the spectrometer,
• wherein each of the first and second compression fitting assemblies of the flow cell further comprises:
• an alignment fitting having a first end and an opposing second end and defining an interior bore proximate to the first end of the alignment fitting that is configured to receive an O-ring seal, wherein the interior bore at the first end of the alignment fitting defines a taper having a decreasing inner diameter in a direction away from the first end of the alignment fitting, wherein the alignment fitting is coupled to the enclosure tube via a first compression seal at the second end of the alignment fitting;
• a compression fitting that receives the second end of the alignment fitting, wherein the compression fitting is coupled to the alignment fitting via a second compression seal, wherein the respective window is received within the compression fitting;
• a nut threadedly engaging the compression fitting, wherein threaded engagement of the nut with the compression fitting causes a biasing force against the respective window;
• a first O-ring compressed between the compression fitting and the respective window;
• a compression sleeve at least partially received within the interior bore of the alignment fitting so that the respective window biases against the compression sleeve;
• and
• a second O-ring received within the interior bore of the alignment fitting and compressed between the compression sleeve and the alignment fitting.