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McIntyre, Dustin L.

Publications and source records attributed to McIntyre, Dustin L..

Scheimpflug LIDAR for Gas Sensing at Elevated Temperatures

Localized operating conditions inside boilers, heat recovery steam generators, or other large thermal systems have a huge impact on the efficiency, environmental performance, and lifetime of components. It is extremely difficult to measure species accurately within these systems due to the high temperatures and harsh environments, locally oxidizing or reducing atmospheres, ash, other particulates, and other damaging chemical species. Physical probes quickly suffer damage and are rendered nonfunctional. This work has attempted to adapt the measurement approach based on Scheimpflug light detection and ranging (S-LIDAR) for the remote sensing of gas species inside the high-temperature boiler environment. For a proof-of-concept, the detection of Raman signals of N 2 , O 2 , and CO 2 and their behavior with increasing temperature have been presented.

47 OTHER INSTRUMENTATION↗

Design, construction, and validation of an in-situ groundwater trace element analyzer with applications in carbon storage

Abstract It is estimated that carbon emissions should reach net-zero by 2050 to meet important climate targets. Carbon capture is likely necessary to reach these targets, requiring a long-term storage solution such as geological carbon sequestration. However, as with any subsurface activity, leakage can occur, potentially impacting groundwater quality near the storage site. Rapid detection is essential to mitigate damage to this resource. Since CO 2 will acidify groundwater, the concentrations of acid soluble minerals and associated cations will increase. Thus, an in-situ, real-time element analysis system based on laser-induced breakdown spectroscopy (LIBS) is under development to monitor these elements. The system splits the traditional LIBS system into a miniature, all-optical sensor head built around a passively Q-switch laser fiber coupled to a control unit. Previous work has validated the LIBS technique for use at high pressure as well as the split system design. In this work, a fieldable prototype sensor is developed and tested in an onsite monitoring well where trace elements concentrations (approx. 0–3 ppm) were tracked over 20 days. These concentrations varied in response to local rainfall, diluting with increased rain, demonstrating the ability of a LIBS-based sensor to track trace elements under real-world conditions.

54 ENVIRONMENTAL SCIENCES↗

Evaluation of analytical performance of double pulse laser-induced breakdown spectroscopy for the detection of rare earth elements

Double pulse laser-induced breakdown spectroscopy (DP-LIBS) in collinear configuration was demonstrated to enhance the signal intensity of three rare earth elements (REEs), Eu, Gd, Pr, and Y (Yttrium is included because of its similar chemical properties and occurrence in similar deposits as REE). Significant enhancement in spectral signals of all elements was observed with an aid of second laser. Two laser pulses of 1064 nm wavelength were employed in collinear geometry on the Pr 2 O 3 , Eu 2 O 3 , Gd 2 O 3 , and Y 2 O 3 pellets to obtain emission spectra. For selected strong emission lines of Eu and Gd signal enhancement was found to be 3 to 7-fold and that for Y and Pr lines was observed to be 3 to 13-fold compared to single-pulse laser-induced breakdown spectroscopy (SP-LIBS). Role of inter-pulse delay between two pulses in DP-LIBS was found to be very crucial. Furthermore, while comparing selected ionic and neutral lines, ionic lines were found to have larger signal enhancement in DP-LIBS at the experimental conditions used in this study.

47 OTHER INSTRUMENTATION↗

Mineral carbonate dissolution with increasing CO 2 pressure measured by underwater laser induced breakdown spectroscopy and its application in carbon sequestration

In this study, the ability of laser-induced breakdown spectroscopy (LIBS) to measure the in situ aqueous dissolution of various mineral carbonates with increasing CO 2 pressure was examined. Dissolution experiments included four geologically common mineral carbonates (CaCO 3 , MgCO 3 , MnCO 3 , SrCO 3 ) and the CO 2 pressure ranged from ambient to 250 bar. The ensuing plasma emission was spectrally analyzed, and the intensities of Ca, Mg, Mn, and Sr emission lines were used to monitor the respective metal cations released to the aqueous solution. The strong emission lines of Ca (Ca II 393.36, Ca II 396.84, Ca I 422.67 nm), Mg (unresolved magnesium doublet: Mg I 383.230, Mg I 383.829 nm), Mn (unresolved manganese triplet: Mn I 403.076, Mn I 403.307, Mn I 403.449 nm), and Sr (Sr II 407.77, Sr II 421.55, Sr I 460.73 nm) were identified in the spectra. The amounts of metals released from their respective carbonates were estimated at different time intervals following the CO 2 injection (5 m, 1, 2, 3, 4, 24 h) and at different pressures (50, 100, 150, 200, 250 bar) using calibration models developed at corresponding pressure settings. The results demonstrated that the pressure-induced dissolution of all carbonates was consistent with their expected and selective pH-dependent solubility. The dissolution rate of CaCO 3 , MgCO 3 , and SrCO 3 was found to be higher than that of MnCO 3 . The dissolution of constituents in a Mt. Simon sandstone associated with a deep saline reservoir at elevated CO 2 pressure was also studied and Ca release was quantified. The results demonstrated that real-time monitoring of carbonate dissolution by LIBS may provide a useful indirect detection system indicative of CO 2 leakage from geologic carbon storage sites.

58 GEOSCIENCES↗

Development of a subsurface LIBS sensor for in situ groundwater quality monitoring with applications in CO 2 leak sensing in carbon sequestration

Sub-surface activity such as geologic carbon sequestration (GCS) has the potential to contaminate groundwater sources with dissolved metals originating from sub-surface brines or leaching of formation rock. Therefore, a Laser Induced Breakdown Spectroscopy (LIBS) based sensor is developed for sub-surface water quality monitoring. The sensor head is built using a low cost passively Q-switched (PQSW) laser and is fiber coupled to a pump laser and a gated spectrometer. The prototype sensor head was constructed using off the shelf components and a custom monolithic, PQSW laser and testing has verified that the fiber coupled design performs as desired. The system shows good calibration linearity for tested elements (Ca, Sr, and K), quick data collection times, and Limits of Detection (LODs) that are comparable to or better than those of table top, actively Q-switched systems. The fiber coupled design gives the ability to separate the PQSW LIBS excitation laser from the pump source and spectrometer, allowing these expensive and fragile components to remain at the surface while only the low-cost, all optical sensor head needs to be exposed to the hostile downhole environment.

58 GEOSCIENCES↗

Evaluating Laser-Induced Breakdown Spectroscopy Sensor Technology for Rapid Source Characterization of Rare Earth Elements

A prototype Laser Induced Breakdown Spectroscopy (LIBS) sensor is tested for the determination of rare earth elements (Eu and Yb) in liquid and solid samples. The sensor head, built using a monolithic passively Q-switched (PQSW) Nd:YAG laser, produced a 1064 nm laser beam with 3.3 ns pulses and an energy of 4.2 mJ. The measurements show good calibration linearity for both Eu and Yb with R 2 values above 0.99 for all analyzed spectral lines in liquid and solid samples. Limits of Detection (LODs) obtained were as low as 1 ppm, which are comparable to or better than those reported previously by using table top actively Q-switched systems. This study aims to develop a high sensitivity, field deployable sensor for characterizing existing and new sources of rare earth elements

47 OTHER INSTRUMENTATION↗

Investigating the CO 2 pressure effect on underwater laser-induced plasma emission of Eu and Yb

Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique for in situ determination of elements in natural resources. The technique is employed for the study of two rare earth elements (Eu and Yb) in aqueous solutions at pressures ranging from ambient to 250 bars. Underwater plasma is created at ambient and elevated pressures to record LIBS spectra from their solutions using Nd:YAG laser operated at its fundamental wavelength of 1064 nm. The effect of CO2 pressure on the characteristic spectral signatures of these two rare earth elements is presented. Variation of intensity, integrated intensity, and width of selected emission lines with CO2 pressure is explained. The technique could potentially be used for the detection of rare earth elements in oceanic, carbon sequestration, and geothermal fluids.

36 MATERIALS SCIENCE↗

Quantification of dissolved metals in high-pressure CO 2 -water solutions by underwater laser-induced breakdown spectroscopy

Underwater laser-induced breakdown spectroscopy has been employed for the measurement of dissolved metals (Mg, Ca, Sr, Ba and Mn) in high-pressure CO 2 -water solutions. The CO 2 pressure was varied over the range from 10 to 400 bars and the concentrations of Mg, Ca, Sr, Ba and Mn were determined by spectral analysis and establishing the calibration curves. Limit of detection (LOD) for Mg, Ca, Sr, Ba, and Mn at 10 bars were found to be 31.7 ppm, 2.5 ppm, 3.3 ppm, 4.4 ppm, and 10.5 ppm, respectively. The LOD for Mg, Ca, Sr, and Ba were unaffected by the pressure however, a 2-fold decrease in LOD of Mn was observed with an increasing pressure from 10 to 400 bars. The results demonstrate that low-ppm range concentrations of Mg, Ca, Sr, Ba and Mn can be precisely measured in CO 2 -charged water at varied pressure conditions by using underwater LIBS. The study has implications in monitoring of CO 2 leak in carbon sequestration.

36 MATERIALS SCIENCE↗

Abstract - Cooperative Research and Development Agreement between Applied Spectra, Inc. and National Energy Technology Laboratory

Applied Spectra, as our industrial collaborator, is helping us develop our downhole LIBS sensor. Our part of the collaboration is the design, construction, and validation of the miniaturized fiber coupled laser whereas Applied Spectra will be providing technical guidance and control/analysis software. This will allow our system which is traditionally operated by a person to be automated in both data collection and analysis. This will allow our system to significantly increase its TRL.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Determination of Rare Earth Elements in Geological Samples Using Laser-Induced Breakdown Spectroscopy (LIBS) [Determination of Rare Earth Elements in Geological Samples by Laser-Induced Breakdown Spectroscopy (LIBS)]

Laser-induced breakdown spectroscopy (LIBS) was used to detect rare earth elements (REEs) in natural geological samples. Low and high intensity emission lines of Ce, La, Nd, Y, Pr, Sm, Eu, Gd, and Dy were identified in the spectra recorded from the samples to claim the presence of these REEs. Multivariate analysis was executed by developing partial least squares regression (PLS-R) models for the quantification of Ce, La, and Nd. Analysis of unknown samples indicated that the prediction results of these samples were found comparable to those obtained by inductively coupled plasma mass spectrometry analysis. In conclusion, data support that LIBS has potential to quantify REEs in geological minerals/ores.

58 GEOSCIENCES↗

Chapter 12 - Laser-Induced Breakdown Spectroscopy: Advanced Analytical Technique

Application of laser-induced breakdown spectroscopy (LIBS) to analyze solid samples and food materials is described in this chapter. A comparative study of the quantitative and qualitative analysis of atomic and molecular emission from LIBS spectra was performed using a mixture of SrCl 2 and Al 2 O 3 in powder form as a sample. The atomic emission from Sr and molecular emission from SrCl and SrO observed in LIBS spectra were analyzed. Calibration data collected at optimum experimental conditions were used to develop calibration curves, which can be used to predict the Sr concentration. Limits of detection for selected atomic and molecular emission spectra were determined. To showcase an application of LIBS technique in food science, analysis of wheat flour tortillas and comparison of organic and conventional vegetables are described. For the comparative study of organic and conventional vegetables, cauliflowers and broccolis were taken as working samples. Presence of the major elemental nutrients in these vegetables was detected by identifying emission lines of those elements in the LIBS spectra obtained from them. Both multivariate and univariate analyses were employed for comparison. Finally, principal component analysis was performed for multivariate analysis, whereas intensities of emission lines of elements were compared in univariate analysis.

47 OTHER INSTRUMENTATION↗

Analysis of charcoal blast furnace slags by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was used for the analysis of charcoal blast furnace slags. Plasma was generated by an application of a 1064 nm wavelength Nd:YAG laser beam to the surface of pellets created from the slags. The presence of Al, Ca, Fe, K, Mg, Mn, and Si was determined by identifying their characteristic spectral signatures. Multivariate analysis was performed for the quantification of these elements. The predicted LIBS results were found in agreement with the inductively coupled plasma optical emission spectrometry analysis. The limit of detection for Al, Ca, Fe, K, Mg, Mn, and Si was calculated to be 0.10%, 0.22%, 0.02%, 0.01%, 0.01%, 0.005%, and 0.18%, respectively.

36 MATERIALS SCIENCE↗

Measurement of Eu and Yb in aqueous solutions by underwater laser induced breakdown spectroscopy

In this paper, we report the use of laser induced breakdown spectroscopy (LIBS) to detect dissolved Eu and Yb in bulk aqueous solutions. Ten strong emission lines of Eu and one strong emission line of Yb were identified in the underwater LIBS spectra obtained by using Czerny–Turner spectrometer within the wavelength range of 375–515 nm. Temporal evolution of plasma and the effect of laser pulse energy on the spectral emission were studied. Finally, calibration curves using the concentration range from 500 to 10,000 ppm were developed and limits of detection for Eu and Yb were estimated to be 209 and 156 ppm, respectively.

36 MATERIALS SCIENCE↗

Multi-point laser ignition device

A multi-point laser device comprising a plurality of optical pumping sources. Each optical pumping source is configured to create pumping excitation energy along a corresponding optical path directed through a high-reflectivity mirror and into substantially different locations within the laser media thereby producing atomic optical emissions at substantially different locations within the laser media and directed along a corresponding optical path of the optical pumping source. An output coupler and one or more output lenses are configured to produce a plurality of lasing events at substantially different times, locations or a combination thereof from the multiple atomic optical emissions produced at substantially different locations within the laser media. The laser media is a single continuous media, preferably grown on a single substrate.

36 MATERIALS SCIENCE↗