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Thursday, July 30, 2020 | History

3 edition of The use of spontaneous Raman scattering for hydrogen leak detection found in the catalog.

The use of spontaneous Raman scattering for hydrogen leak detection

The use of spontaneous Raman scattering for hydrogen leak detection

  • 293 Want to read
  • 27 Currently reading

Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, D.C.], [Springfield, Va .
Written in English

    Subjects:
  • Gas detectors.,
  • Hydrogen.,
  • Laser spectroscopy.,
  • Leakage.,
  • Raman spectra.,
  • Raman spectroscopy.

  • Edition Notes

    StatementWim A. de Groot.
    SeriesNASA contractor report -- 195373., NASA contractor report -- NASA CR-195373.
    ContributionsUnited States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15404359M

    RRS is a minor modification of spontaneous Raman scattering. The intensity of Raman spectrum components increases by up to six orders of magnitude if the energy of the pump beam coincides with an electronic transition of the molecule (i.e., the difference between the two energy levels involved). The method is described in. For the study of adsorption of hydrogen in MOF-5, crystals were prepared as described earlier [7], evacuated for 18 h in a Raman cell, and exposed to an atmosphere of H 2 ( bar). Room temperature Raman spectra were collected with a Renishaw inVia Raman Micro-scope in extended scan mode between and cm 1. A 25 mW nm argon-ion.

    Rayleigh and Raman scattering by hydrogen and caesium To solve (6a) and (66) we write If the initial and final states are s states of zero orbital angular momentum and V(r) is a central field potential, u.(r) and ub(r) are solutions of the radial equations satisfying the,boundary conditions uo,b(r)+r2 as r+O, ub(r)+O as r+m for all.   Compared to the use of chirped fs pul a key advantage of our approach is the full control of the spectral width or temporal duration of the outputs with the pulse shaping technique. In our earlier work, 14, 29 we showed that for Raman bands with a half width of ∼5 cm −1 the decrease in signal level is small when the pulse.

    Both spontaneous Raman scattering and stimulated Raman scattering (SRS) have been studied for trace-gas detection. However, Raman scattering is typically very weak and the discrimination of spontaneous Raman scattering against background such as Rayleigh scattering is poor especially for pure rotational Raman bands that have small Raman shifts. The Raman spectrum of hydrogen offers a particularly favourable case for an experimental test of this point, as the individual rotational lines are well separated from the exciting line. Working.


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The use of spontaneous Raman scattering for hydrogen leak detection Download PDF EPUB FB2

Time leak detection is spontaneous Raman scattering. In addition, a leak detection system based on spontaneous Raman scattering could be made small and light weight, so that it can be used during the preparation, in-flight, and retum phases of the mission and, additionally, should not require intensive personnel impact.

Hydrogen leak detection. The use of spontaneous Raman scattering for hydrogen leak detection. Hydrogen leak detection using Raman. spectroscopy is chosen for this investigation for. previously mentioned reasons. Get this from a library.

The use of spontaneous Raman scattering for hydrogen leak detection. [Wim A De Groot; United States. National Aeronautics and Space Administration.]. A fiber optic probe has been built and demonstrated that utilizes back scattered spontaneous Raman spectroscopy to detect and identify gaseous species.

The small probe, coupled to the laser and data acquisition equipment with optical fibers, has applications in gaseous leak detection and process monitoring.

The probe design and data acquisition system are described. Raman scattering Cited by: The Use of Spontaneous Raman Scattering for Hydrogen Leak Detection. By Wim A. Degroot. Abstract. A fiber optic probe has been built and demonstrated that utilizes back scattered spontaneous Raman spectroscopy to detect and identify gaseous species.

The small probe, coupled to the laser and data acquisition equipment with optical fibers, has Author: Wim A. Degroot. American Institute of Aeronautics and Astronautics Sunrise Valley Drive, Suite Reston, VA A compact Raman lidar system for hydrogen gas leak detection was constructed.

Laser-induced fluorescence at a distance of 70 m and Raman scattering light from N2 gas at short range could be detected. This e-book is an essential review of land-based laser sensing methods, such as differential absorption, Raman scattering, laser-induced fluorescence, Doppler effect methods, laser-induced breakdown spectroscopy, and laser ultrasonics, and their respective application to specific industrial needs, such as natural gas leak detection, hydrogen gas leak detection, pollutant detection, wind.

Raman scattering detection was accomplished for the hydrogen gas with a compact Diode Pumped Solid State (DPSS) laser-based Raman lidar. The quantitative measurement was conducted on the hydrogen gas concentration of 1 - % and the detectable distance of.

Stimulated Raman Scattering in H 2 has been widely used to extend the frequency range of tunable lasers, such as dye lasers. This technique was first demonstrated by Schmidt and Appt () using room-temperature hydrogen at a pressure of atmospheres. This is mentioned because, though simple, the use of pressurized hydrogen requires stainless steel cells and detailed attention to safety.

Stimulated Raman spectroscopy, also referred to as stimulated raman scattering (SRS) is a form of spectroscopy employed in physics, chemistry, biology, and other fields. The basic mechanism resembles that of spontaneous Raman spectroscopy: a pump photon, of the angular frequency, which is absorbed by a molecule has some small probability of inducing some vibrational (or rotational) transition.

Gas compositions are usually measured by using IR light absorption sensors or Raman scattering sensors and can be combined with optical fibres to confine the molecule detection at a microscale. This chapter presents principles for sensing different gas components, possible types of optical fibre systems solutions for gas detection and.

Raman spectroscopy (/ ˈ r ɑː m ən /); (named after Indian physicist C. Raman) is a spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed.

Raman spectroscopy is commonly used in chemistry to provide a structural fingerprint by which molecules can be identified. Raman spectroscopy: Basic principles and applications • Basic principles - Resonance Raman scattering - Surface Enhanced Raman Scattering (SERS) • Instrumentation -Spectrometer - Excitation sources • Raman in catalysis - In situ cells - In situ Raman (of working catalysts) C.V.

Raman (). 1. Introduction. The first experiment of stimulated Raman scattering (SRS) is proved in [], the next studies have been conducted by solving the coupled equations for the evolution of the pump and Stokes intensities to the excitation of the Raman medium [2,3].A full quantum mechanical solution to SRS that unifies the spontaneous emission and the spatial propagation was developed in.

Improved sensitivity gas detection by spontaneous Raman scattering Article (PDF Available) in Applied Optics 48(22) September with 59 Reads How we measure 'reads'. Existing Hydrogen Leak Detection Schemes using Raman Scattering Spontaneous Raman scattering has long been a common laboratory technique for species identification and quantification.

The development of the laser with its ability to provide a high intensity, monochromatic light source was an important advance in Raman spectroscopy.

Spontaneous scattering is also more susceptible to contamination from spontaneous plasma emission and stray laser scattering. However, spatially-resolved measurements are possible when signal-to-noise is sufficiently high, using line-wise Raman spectra obtained by imaging the measurement region onto the spectrometer slit [ 21, 22 ].

Rotational and vibrational spontaneous Raman scattering (SRS) spectra of H 2, N 2 and H 2 O have been measured in H 2 –air flames at pressures up to bar as a first step towards establishing a comprehensive Raman spectral database for temperatures and species in high-pressure combustion.

We have obtained an initial set of measurements that indicate the spectra are of. (in cm 2/sr-1) the differential Raman scattering cross-section Near the detection limit-1, = photons.s Raman Pj m. EMU-CNRS International School: Applications of Raman Spectroscopy to Earth Sciences and cultural Heritage: th of june Detection limit with a microspectrometer.

investigation of gaseous hydrogen leak detection using raman scattering and laser-induced breakdown spectroscopy by allen joseph ball a thesis presented to the graduate school of the university of florida in partial fulfillment of the requirements for the degree of .Letter we show that, by using liquid hydrogen as the droplet medium, one can achieve a high-Q value that exceeds for WGMs, even in the UV.

We show also that a high-Q liquid-hydrogen droplet (LHD) can gen-erate stimulated Raman scattering (SRS) sidebands that cover a broad spectral range from the UV to the near IR. Notwithstanding the advantages, spontaneous Raman scattering is a “very feeble secondary radiation.” 2 2.

C. V. Raman, Proc. Indian Acad. Sci., Sect. A 37(3), – (). The Raman scattering cross section is typically on the level of 10 −30 cm 2 per molecule, which is about 10 11 times smaller than the IR absorption cross section.