Abstract: A calibration reference for a multipass Raman analysis system, wherein a combination excitation and collection beam passes through a focal point F0 within a sample volume multiple times, is provided. The calibration reference includes a body of material having a known spectral response when illuminated by the combination excitation and collection beam. The size or shape of the body is selected or modified to keep the focal point at F0 within the body when the body is positioned within the sample volume for calibration purposes.

Abstract: A method for determining an amount of a Raman-invisible gas in a multi-component gas stream includes performing a first and second absolute Raman analysis on the gas stream. A decrease in the absolute Raman bands from the first analysis to the second analysis is attributed to an increase of the Raman-invisible gas in the gas stream. The amount of the Raman-invisible gas is calculated from the difference between the first and second sets of Raman bands. The calculation of the Raman-invisible gas is verified via a measurement and a calculation of a secondary property of the gas stream such as the thermal conductivity of the gas stream or the density of the gas stream.

Abstract: A method for determining an amount of a Raman-invisible gas in a multi-component gas stream includes performing a first and second absolute Raman analysis on the gas stream. A decrease in the absolute Raman bands from the first analysis to the second analysis is attributed to an increase of the Raman-invisible gas in the gas stream. The amount of the Raman-invisible gas is calculated from the difference between the first and second sets of Raman bands. The calculation of the Raman-invisible gas is verified via a measurement and a calculation of a secondary property of the gas stream such as the thermal conductivity of the gas stream or the density of the gas stream.

Abstract: The present disclosure includes discloses a method for analyzing a multi-component gas sample using spectroscopy in combination with the measurement of extrinsic or intrinsic properties of the gas sample. The results of the spectroscopic analysis and the measurement are combined to quantify a gas component unseen by the spectroscopic analysis.

Abstract: An improved method of sealing a window into an aperture in a body uses a lubricant comprising polymer particles suspended in a volatile, low viscosity, low surface tension carrier fluid. The carrier fluid is applied to one or both of the sidewalls of the window and aperture, and the window is pressed into the aperture such that the carrier fluid evaporates, leaving the polymer particles to fill interstitial surface voids, while enabling the sidewall of the window to make intimate mechanical contact with the sidewall of the aperture. While having broader application, the present disclosure finds particular utility in optical characterization techniques based upon the Raman effect and fluorescence probes used in process monitoring and control.

Abstract: A standard reference material interface for a Raman probe includes a locator including a housing having a first end and a second end, the first end including an attachment portion configured to mate with an attachment portion of the Raman probe. The locator defines a central axis that intersects the first end and the second end. The standard reference material interface also includes a hermetically sealed standard reference material enclosure positioned at the second end of the housing and enclosing a standard reference material. An optical port is positioned within the housing between the Raman probe and the standard reference material relative to the central axis. The optical port includes a window.

Abstract: A method for harmonizing the responses of a plurality of Raman analyzers includes steps of calibrating an intensity axis response of a spectrometer to a reference light source and measuring a laser wavelength of a laser using the spectrometer. The method also includes steps of measuring a fluorescence spectrum induced by the laser at the laser wavelength of a plurality of standard reference material samples using the spectrometer, measuring a temperature of each standard reference material sample while measuring the fluorescence spectrum, and correcting the fluorescence spectrum of each standard reference material sample based on the respective temperature. The method further includes steps of deploying each standard reference material sample in one of a plurality of field calibrator devices and calibrating the intensity axis of one of the Raman analyzers using one of the field calibrator devices and the corrected fluorescence spectrum of the respective standard reference material sample.

Abstract: A method for harmonizing the responses of a plurality of Raman analyzers includes steps of calibrating an intensity axis response of a spectrometer to a reference light source and measuring a laser wavelength of a laser using the spectrometer. The method also includes steps of measuring a fluorescence spectrum induced by the laser at the laser wavelength of a plurality of standard reference material samples using the spectrometer, measuring a temperature of each standard reference material sample while measuring the fluorescence spectrum, and correcting the fluorescence spectrum of each standard reference material sample based on the respective temperature. The method further includes steps of deploying each standard reference material sample in one of a plurality of field calibrator devices and calibrating the intensity axis of one of the Raman analyzers using one of the field calibrator devices and the corrected fluorescence spectrum of the respective standard reference material sample.

Abstract: The present disclosure includes discloses a method for analyzing a multi-component gas sample using spectroscopy in combination with the measurement of extrinsic or intrinsic properties of the gas sample. The results of the spectroscopic analysis and the measurement are combined to quantify a gas component unseen by the spectroscopic analysis.

Abstract: A standard reference material interface for a Raman probe includes a locator including a housing having a first end and a second end, the first end including an attachment portion configured to mate with an attachment portion of the Raman probe. The locator defines a central axis that intersects the first end and the second end. The standard reference material interface also includes a hermetically sealed standard reference material enclosure positioned at the second end of the housing and enclosing a standard reference material. An optical port is positioned within the housing between the Raman probe and the standard reference material relative to the central axis. The optical port includes a window.

Abstract: An improved method of sealing a window into an aperture in a body uses a lubricant comprising polytetrafluoroethylene (PTFE) particles suspended in a volatile, low viscosity, low surface tension carrier fluid. The carrier fluid is applied to one or both of the sidewalls of the window and aperture, and the window is pressed into the aperture such that the carrier fluid evaporates, leaving the PTFE particles to fill interstitial surface voids, while enabling the sidewall of the window to make intimate mechanical contact with the sidewall of the aperture. While having broader application, the present disclosure finds particular utility in optical characterization techniques based upon the Raman effect and fluorescence probes used in process monitoring and control.

Abstract: The present disclosure includes discloses a method for analyzing a multi-component gas sample using spectroscopy in combination with the measurement of extrinsic or intrinsic properties of the gas sample. The results of the spectroscopic analysis and the measurement are combined to quantify a gas component unseen by the spectroscopic analysis.

Abstract: A radiation shield for near-infrared detectors of the type used in Raman spectroscopic systems comprises a chamber enclosing the detector and a cooling device in thermal contact with the chamber and the detector to reduce the level of unwanted radiation to which the detector would otherwise be exposed. The chamber may include a window in optical alignment with the detector, and the window may include one or more coatings to pass wavelengths in a range of interest or block radiation at wavelengths outside of this range. The shield may be enclosed in an evacuated dewar having a window which may also include one or more coatings to favor the wavelength range.

Abstract: A Raman spectroscopic measurement system for measuring the material composition of a mixed phase fluid having a gas phase dispersed in a liquid phase or vice versa is disclosed, which includes an insert to be inserted into a process. The insert includes a measurement chamber partially defined by a phase separating membrane that enables the gas phase to diffuse into and out of the measurement chamber and facilitates coalescing of the liquid phase which into a collector. A first probe of the measurement system is configured to transmit excitation light into the measurement chamber and to receive a Raman signal emanating from the gas phase therein, and a second probe is configured to transmit excitation light into the drain and to receive a Raman signal emanating from the liquid phase therein. The measurement system further includes a spectrometer to determine the material composition of the fluid from the Raman signals.

Abstract: A Raman spectroscopic measurement system for measuring the material composition of a mixed phase fluid having a gas phase dispersed in a liquid phase or vice versa is disclosed, which includes an insert to be inserted into a process. The insert includes a measurement chamber partially defined by a phase separating membrane that enables the gas phase to diffuse into and out of the measurement chamber and facilitates coalescing of the liquid phase which into a collector. A first probe of the measurement system is configured to transmit excitation light into the measurement chamber and to receive a Raman signal emanating from the gas phase therein, and a second probe is configured to transmit excitation light into the drain and to receive a Raman signal emanating from the liquid phase therein. The measurement system further includes a spectrometer to determine the material composition of the fluid from the Raman signals.

Abstract: The present disclosure includes discloses a method for analyzing a multi-component gas sample using spectroscopy in combination with the measurement of extrinsic or intrinsic properties of the gas sample. The results of the spectroscopic analysis and the measurement are combined to quantify a gas component unseen by the spectroscopic analysis.

Abstract: Methods and systems for spectrometer dark correction are described which achieve more stable baselines, especially towards the edges where intensity correction magnifies any non-zero results of dark subtraction, and changes in dark current due to changes in temperature of the camera window frame are typically more pronounced. The resulting induced curvature of the baseline makes quantitation difficult in these regions. Use of the invention may provide metrics for the identification of system failure states such as loss of camera vacuum seal, drift in the temperature stabilization, and light leaks. In system aspects of the invention, a processor receives signals from a light detector in the spectrometer and executes software programs to calculate spectral responses, sum or average results, and perform other operations necessary to carry out the disclosed methods. In most preferred embodiments, the light signals received from a sample are used for Raman analysis.

Abstract: Systems and methods are used to couple an optical sampling probe to a port in a single-use bioreactor bag for in-process monitoring. A combination of re-useable and disposable components maintain precision while reducing costs. A disposable barb with an integral window, received by the port of the reaction vessel, is coupled to a re-useable optic component with a focusing lens. A separate focus alignment tool is used to set the lens position to a precise focal point before placement of the optic component into the barb. The fixture includes a window to simulate the window in a barb component, a target with a known spectral signature, and a probe head coupled to a spectral analyzer. The axial position of the lens is adjusted with respect to the spacer component to maximize the spectral signature from a sample target, whereupon the spacer component is bonded to the lens mount.

Abstract: The present disclosure relates to assistive mechanisms and methods that aid an operator of a spectrometer to make spectral measurements of a sample, the measurements having a desired quality. The method enables quality spectral measurements quickly and simply, without a prior understanding of a sample's spectrum or of the details as to how the spectrum is measured. Data quality is improved, and the time required to collect the data is reduced. While a specific example of sample optic focus is disclosed in detail, the optimization of numerous other parameters is possible.

Abstract: The present disclosure relates to assistive mechanisms and methods that aid an operator of a spectrometer to make spectral measurements of a sample, the measurements having a desired quality. The method enables quality spectral measurements quickly and simply, without a prior understanding of a sample's spectrum or of the details as to how the spectrum is measured. Data quality is improved, and the time required to collect the data is reduced. While a specific example of sample optic focus is disclosed in detail, the optimization of numerous other parameters is possible.