Performance of Fiber-Optic Raman Probes for Analysis of Gas Mixtures in Enclosures

Berg, John M.; Rau, Karen; Veirs, D. K.; Worl, Laura A.; McFarlan, James T.; Hill, Daniel

doi:10.1366/0003702021954250

Cited by 13 publications

(12 citation statements)

References 14 publications

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“…As one practical application, we can mention that the spectrophotometer with the opto-mechanical system will be employed to test ''long pass'' filters deposited upon optical fiber tips for efficient biomedical Raman probes. [26][27][28] Results from that study will be published elsewhere.…”

Section: Discussionmentioning

confidence: 99%

A Novel Opto-Mechanical System Coupled to a Spectrophotometer for Measuring Coatings on Small Size Substrates and Optical Fiber Filters

Lima

Pacheco

Villaverde

et al. 2009

Instrumentation Science & Technology

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A novel opto-mechanical system coupled to a commercial spectrophotometer using optical fibers was developed to measure optical transmittance of small samples, like filters deposited on optical fiber tips or micrometric substrates, as well as to investigate transmission uniformity of filters by surface scanning. It consists of two identical modules, reference and sample, both inserted in the chamber of the spectrophotometer. Each module was formed by an optical fiber, 200 mm core diameter and numerical aperture of 0.22, supported by adjustable positioning mounts for easing alignment. The system was validated by measuring the transmittance spectrum of a coated glass substrate with and without the opto-mechanical system, showing no significant differences between both methods. To determine the system versatility were undergone two transmittance experiments: one for a filter deposited on the tip of an optical fiber and the other by scanning the surface of a coated glass substrate. It can be concluded that the opto-mechanical system allows to measurement the transmittance of small size filters and optical fibers filters, as well as to scan over large coated surfaces to investigate coating uniformity.

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Section: Discussionmentioning

confidence: 99%

A Novel Opto-Mechanical System Coupled to a Spectrophotometer for Measuring Coatings on Small Size Substrates and Optical Fiber Filters

Lima

Pacheco

Villaverde

et al. 2009

Instrumentation Science & Technology

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show abstract

“…a multipass gas cell or a pressurizing collection chamber) are not necessary to obtain low detection limits. As the equipment used by Berg 24 was similar to ours, it is likely that the differences arise from their emphasis on characterizing background noise rather than increasing Raman scattering. Pressurized gas cell Filtered 6-around-1 probe Angled collection fibers [24] 0.…”

Section: Conventional Raman Measurementsmentioning

confidence: 92%

“…As the equipment used by Berg 24 was similar to ours, it is likely that the differences arise from their emphasis on characterizing background noise rather than increasing Raman scattering. Pressurized gas cell Filtered 6-around-1 probe Angled collection fibers [24] 0. In passing, we note a brief experiment in which the beam block is replaced with a spherical mirror positioned with excitation fiber at its focus.…”

Section: Conventional Raman Measurementsmentioning

confidence: 92%

“…Berg and co-workers have described some practical considerations of using these probes. 24 They examined the effect of probe (angle and numerical aperture of fibers, use of windows and internal filters) and sample chamber design on collected Raman and background scattering. They found that non-imaging, unfiltered probes achieve lower detection limits than filtered, imaging probes as long as the sample chamber does not lead to excess scattering and that a protective window is not incorporated into the probe tip.…”

Section: Conventional Raman Measurementsmentioning

confidence: 99%

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Isotopic hydrogen analysis via conventional and surface-enhanced fiber optic Raman spectroscopy

Lascola

Zeigler

McWhorter

et al. 2004

Advanced Environmental, Chemical, and Biological Sensing Technologies II

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This report describes laboratory development and process plant applications of Raman spectroscopy for detection of hydrogen isotopes in the Tritium Facilities at the Savannah River Site (SRS), a U.S. Department of Energy complex. Raman spectroscopy provides a lower-cost, in situ alternative to mass spectrometry techniques currently employed at SRS. Using conventional Raman and fiber optics, we have measured, in the production facility glove boxes, process mixtures of protium and deuterium at various compositions and total pressures ranging from 1000 -4000 torr, with detection limits ranging from 1-2% for as low as 3-second integration times. We are currently investigating fabrication techniques for SERS surfaces in order to measure trace (0.01-0.1%) amounts of one isotope in the presence of the other. These efforts have concentrated on surfaces containing palladium, which promotes hydrogen dissociation and forms metal hydride bonds, essentially providing a chemical enhancement mechanism.

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“…[12,13,14,15,16] At SRS, remote chemical analysis using the Raman technique has been explored by Nave and coworkers. [17,18] This work used a rugged diffuse reflectance 6-around-1 probe.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Technologies to Complement/Replace Mass Spectrometers in the Tritium Facilities

Tovo¹,

Lascola²,

Spencer³

et al. 2005

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EXECUTIVE SUMMARYThe problem of the aging mass spectrometers coupled with lack of vendor support and no viable commercially available replacement presents risks for process control and monitoring in the Tritium Facilities. Therefore, several technologies were evaluated to maintain and, if possible, to enhance the current analytical capabilities provided by the existing mass spectrometers. These technologies included potential replacement/complement mass spectrometers as well as on-line sensors. Based on the results of this evaluation, the Savannah River National Laboratory (SRNL) makes the following recommendations.• Work should begin on implementation of the Quantra Fourier Transform-Ion CyclotronResonance (FT-ICR) as a complement to the existing mass spectrometers or as an on-line process analyzer. In its current configuration, the instrument can measure masses 12 or greater, with a resolution of 30,000 at mass 28, and 100 part per million detection limit using ion ejection of major ions. Thus, the 16-24 mass region that is not so easily separated by the existing Tritium Facility mass spectrometers could be resolved and measured using the FT-ICR. For the FT-ICR (Quantra) to be of even more benefit to the Tritium Facilities, it should be reengineered to provide analysis of masses 2-1000 in a single scan as well as other hardware and software improvements identified during our evaluation (i.e. long term stability, quantitative analysis of mixtures, etc.). In collaboration, SRS, LANL, and Y12 have secured funding for this project and the re-engineering effort will begin in FY06. Once the re-engineering effort is complete, funding will be required for performance testing and implementation in a tritiated environment as well as validation with the design agency.• The bench top magnetic sector mass spectrometer (GCMATE) technology closely matches that of the existing mass spectrometers in the Tritium Facilities. The initial work with the GCMATE indicates that its resolution and sensitivity meet the requirements of a replacement mass spectrometer for the Tritium Facilities. Although this instrument appears to be the most promising as a replacement for the existing mass spectrometers, delayed funding in FY05 precluded a complete evaluation. Therefore, evaluation of this instrument should continue in FY06.• Fiber optic Raman Spectroscopy has been demonstrated as a useful on-line technology for measurement of hydrogen isotopes at a concentration of greater than 1%. The method should be demonstrated on a process containing tritium. Upon successful demonstration in a tritium process, the method should then be implemented on the Hydrogen-Tritium Thermal Cycling Adsorption Process (HT-TCAP) and other processes that would require a detection limit of 1% or greater. Research and development to improve the detection limit of the fiber optic Raman method should continue as this would allow on-line analysis of other process points (i.e. HT-TCAP product and raffinate, Tritium Process Stripper, etc.).• The on-line vapochromic sens...

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Performance of Fiber-Optic Raman Probes for Analysis of Gas Mixtures in Enclosures

Cited by 13 publications

References 14 publications

A Novel Opto-Mechanical System Coupled to a Spectrophotometer for Measuring Coatings on Small Size Substrates and Optical Fiber Filters

A Novel Opto-Mechanical System Coupled to a Spectrophotometer for Measuring Coatings on Small Size Substrates and Optical Fiber Filters

Isotopic hydrogen analysis via conventional and surface-enhanced fiber optic Raman spectroscopy

Evaluation of Technologies to Complement/Replace Mass Spectrometers in the Tritium Facilities

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