Science.gov

Sample records for absorption spectrometer system

  1. Multielement continuum-source atomic-absorption spectrometry with an echelle-spectrometer/image-dissector system.

    PubMed

    Masters, R; Hsiech, C; Pardue, H L

    1989-01-01

    The continued development of the echelle-spectrometer/image-dissector system for multielement determination by continuum-source atomic-absorption spectrometry is presented. Modifications of the instruments include the use of a 20-groove/mm echelle grating blazed at 76 degrees , and the removal of the magnetic shield from the image dissector. The spectral range is from 300 to 430 nm and the observed resolution is better than 0.005 nm at 400 nm. Calibration curves are linear up to an absorbance of 0.2, and absorption sensitivities are up to 4-fold better than with the previous design. Fundamental characteristics of the detector limit the application of the instrument to sequential single-element quantifications with the electrothermal atomizer, and to sequential multielement quantification with the flame atomizer. The further development of the instrument for simultaneous multielement qualification is discussed. PMID:18964682

  2. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  3. A wide spectral range photoacoustic aerosol absorption spectrometer.

    PubMed

    Haisch, C; Menzenbach, P; Bladt, H; Niessner, R

    2012-11-01

    A photoacoustic spectrometer for the measurement of aerosol absorption spectra, based on the excitation of a pulsed nanosecond optical parametrical oscillator (OPO), will be introduced. This spectrometer is working at ambient pressure and can be used to detect and characterize different classes of aerosols. The spectrometer features a spectral range of 410 to 2500 nm and a sensitivity of 2.5 × 10(-7) m(-1) at 550 nm. A full characterization of the system in the visible spectral range is demonstrated, and the potential of the system for near IR measurement is discussed. In the example of different kinds of soot particles, the performance of the spectrometer was assessed. As we demonstrate, it is possible to determine a specific optical absorption per particle by a combination of the new spectrometer with an aerosol particle counter. PMID:23035870

  4. Scanning imaging absorption spectrometer for atmospheric chartography

    NASA Technical Reports Server (NTRS)

    Burrows, John P.; Chance, Kelly V.

    1991-01-01

    The SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY is an instrument which measures backscattered, reflected, and transmitted light from the earth's atmosphere and surface. SCIAMACHY has eight spectral channels which observe simultaneously the spectral region between 240 and 1700 nm and selected windows between 1940 and 2400 nm. Each spectral channel contains a grating and linear diode array detector. SCIAMACHY observes the atmosphere in nadir, limb, and solar and lunar occultation viewing geometries.

  5. Differential optical absorption spectrometer for measurement of tropospheric pollutants

    NASA Astrophysics Data System (ADS)

    Evangelisti, F.; Baroncelli, A.; Bonasoni, P.; Giovanelli, G.; Ravegnani, F.

    1995-05-01

    Our institute has recently developed a differential optical absorption spectrometry system called the gas analyzer spectrometer correlating optical absorption differences (GASCOAD), which features as a detector a linear image sensor that uses an artificial light source for long-path tropospheric-pollution monitoring. The GASCOAD, its method of eliminating interference from background sky light, and subsequent spectral analysis are reported and discussed. The spectrometer was used from 7 to 22 February 1993 in Milan, a heavily polluted metropolitan area, to measure the concentrations of SO2, NO2, O3, and HNO2 averaged over a 1.7-km horizontal light path. The findings are reported and briefly discussed.

  6. Modeling of intensity-modulated continuous-wave laser absorption spectrometer systems for atmospheric CO(2) column measurements.

    PubMed

    Lin, Bing; Ismail, Syed; Wallace Harrison, F; Browell, Edward V; Nehrir, Amin R; Dobler, Jeremy; Moore, Berrien; Refaat, Tamer; Kooi, Susan A

    2013-10-10

    The focus of this study is to model and validate the performance of intensity-modulated continuous-wave (IM-CW) CO(2) laser absorption spectrometer (LAS) systems and their CO(2) column measurements from airborne and satellite platforms. The model accounts for all fundamental physics of the instruments and their related CO(2) measurement environments, and the modeling results are presented statistically from simulation ensembles that include noise sources and uncertainties related to the LAS instruments and the measurement environments. The characteristics of simulated LAS systems are based on existing technologies and their implementation in existing systems. The modeled instruments are specifically assumed to be IM-CW LAS systems such as the Exelis' airborne multifunctional fiber laser lidar (MFLL) operating in the 1.57 μm CO(2) absorption band. Atmospheric effects due to variations in CO(2), solar radiation, and thin clouds, are also included in the model. Model results are shown to agree well with LAS atmospheric CO(2) measurement performance. For example, the relative bias errors of both MFLL simulated and measured CO(2) differential optical depths were found to agree to within a few tenths of a percent when compared to the in situ observations from the flight of 3 August 2011 over Railroad Valley (RRV), Nevada, during the summer 2011 flight campaign. In addition, the horizontal variations in the model CO(2) differential optical depths were also found to be consistent with those from MFLL measurements. In general, the modeled and measured signal-to-noise ratios (SNRs) of the CO(2) column differential optical depths (τd) agreed to within about 30%. Model simulations of a spaceborne IM-CW LAS system in a 390 km dawn/dusk orbit for CO(2) column measurements showed that with a total of 42 W of transmitted power for one offline and two different sideline channels (placed at different locations on the side of the CO(2) absorption line), the accuracy of the

  7. Fourier Transform Spectrometer System

    NASA Technical Reports Server (NTRS)

    Campbell, Joel F. (Inventor)

    2014-01-01

    A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

  8. Simple system for measuring tritium Ad/absorption using a 2. pi. counter and thermal desorption spectrometer

    SciTech Connect

    Miyake, H.; Matsuyama, M.; Watanabe, K. ); Cowgill, D.F. )

    1992-03-01

    In this paper, the authors develop a simple system using tritium tracer and thermal desorption techniques to measure the tritium adsorption and/or absorption on/in a material having typical surface conditions: namely, not cleaned surface. The tritium counting devices used were a 2{pi} counter and conventional proportional counter. With this system, the amounts of ad/absorption could be measured without exposing the samples to air after exposing them to tritium gas. The overall efficiency (F) of the 2{pi} counter was described at F = exp({minus}2.64h), where h is the distance from the sample to the detector. Ad/absorption measurements were carried out for several materials used for fabricating conventional vacuum systems. The results were, in the order of decreasing amounts of ad/absorption, as (fiber reinforced plastics(FRP)) {gt} (nickel(Ni), molybdenum disulfide(MoS{sub 2})) {gt} (stainless steel (SS304), iron(Fe), aluminum alloy(A2219)) {gt} (boron nitride(h-BN), silicon carbide (SiC), SS304 passivated by anodic oxidation layers(ASS) and that by boron nitride segregation layers (BSS)). The relative amounts were abut 100 for Ni and 0.1 for ASS and BSS, being normalized to Fe = 1.

  9. Feasibility study on 1.6 μm continuous-wave modulation laser absorption spectrometer system for measurement of global CO2 concentration from a satellite.

    PubMed

    Kameyama, Shumpei; Imaki, Masaharu; Hirano, Yoshihito; Ueno, Shinichi; Kawakami, Shuji; Sakaizawa, Daisuke; Kimura, Toshiyoshi; Nakajima, Masakatsu

    2011-05-10

    A feasibility study is carried out on a 1.6 μm continuous-wave modulation laser absorption spectrometer system for measurement of global CO(2)concentration from a satellite. The studies are performed for wavelength selection and both systematic and random error analyses. The systematic error in the differential absorption optical depth (DAOD) is mainly caused by the temperature estimation error, surface pressure estimation error, altitude estimation error, and ON wavelength instability. The systematic errors caused by unwanted backscattering from background aerosols and dust aerosols can be reduced to less than 0.26% by using a modulation frequency of around 200 kHz, when backscatter coefficients of these unwanted backscattering have a simple profile on altitude. The influence of backscattering from cirrus clouds is much larger than that of dust aerosols. The transmission power required to reduce the random error in the DAOD to 0.26% is determined by the signal-to-noise ratio and the carrier-to-noise ratio calculations. For a satellite altitude of 400 km and receiving aperture diameter of 1 m, the required transmission power is approximately 18 W and 70 W when albedo is 0.31 and 0.08, respectively; the total measurement time in this case is 4 s, which corresponds to a horizontal resolution of 28 km. PMID:21556107

  10. Improved multisphere spectrometer system

    SciTech Connect

    Shonka, J.J.; Schwahn, S.O.; Rogers, P.E.; Misko, C.J.

    1991-01-01

    Shonka Research Associated undertook a research program to improve the capabilities and ease of use of the Bonner sphere spectrometer system. Two key elements formed the heart of this research: replacement of the lithium iodide (LiI(Eu)) detector normally used in the spectrometer system with a spherical boron triflouride (BF{sub 3}) proportional counter and exploitation of an optimized set of nested polyethylene spheres, including boron-loaded spherical shells. Use of a spherical BF{sub 3} detector offers many advantages over the LiI(Eu) crystal. The BF{sub 3} detectors are insensitive to gamma radiation. Lack of gamma sensitivity permits acquiring data with simple electronics and allows determination of neutron spectra and dose in lower neutron-to-gamma ratio fields, including background terrestrial radiation fields. The importance of the lack of gamma sensitivity is underscored by the pending changes in neutron quality factors. The nearly perfect spherical symmetry offers advantages for BF{sub 3} over LiI(Eu) detectors as well. A light pipe, which perturbs measurements, is not needed. The bare BF{sub 3} detector response is not affected by the moderation of neutrons as is the case of the organic light pipe used with LiI(Eu). The spherical symmetry permits the use of smaller diameter shells, which add to the number of response functions.

  11. Modular Total Absorption Spectrometer at the HRIBF (ORNL, Oak Ridge)

    SciTech Connect

    Wolińska-Cichocka, M.; Rykaczewski, K.P.; Fijałkowska, A.; Karny, M.; Grzywacz, R.K.; Gross, C.J.; Johnson, J.W.; Rasco, B.C.; Zganjar, E.F.

    2014-06-15

    The Modular Total Absorption Spectrometer (MTAS) array has been designed, constructed, characterized, and applied to the decay studies of {sup 238}U fission products at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Laboratory. A MTAS commissioning run was performed in January 2012 at the mass separator on-line to the HRIBF Tandem accelerator. Preliminary results of MTAS data confirm known decay patterns of {sup 142}Ba and {sup 142}La deduced from an earlier study using a total absorption spectrometer technique.

  12. Absorption spectrometer balloon flight and iodine investigations

    NASA Technical Reports Server (NTRS)

    1970-01-01

    A high altitude balloon flight experiment to determine the technical feasibility of employing absorption spectroscopy to measure SO2 and NO2 gases in the earth's atmosphere from above the atmospheric ozone layer is discussed. In addition to the balloon experiment the contract includes a ground-based survey of natural I emissions from geological sources and studies of the feasibility of mapping I2 from spacecraft. This report is divided into three major sections as follows: (1) the planning engineering and execution of the balloon experiment, (2) data reduction and analysis of the balloon data, and (3) the results of the I2 phase of the contract.

  13. [Spectral calibration for space-borne differential optical absorption spectrometer].

    PubMed

    Zhou, Hai-Jin; Liu, Wen-Qing; Si, Fu-Qi; Zhao, Min-Jie; Jiang, Yu; Xue, Hui

    2012-11-01

    Space-borne differential optical absorption spectrometer is used for remote sensing of atmospheric trace gas global distribution. This instrument acquires high accuracy UV/Vis radiation scattered or reflected by air or earth surface, and can monitor distribution and variation of trace gases based on differential optical absorption spectrum algorithm. Spectral calibration is the premise and base of quantification of remote sensing data of the instrument, and the precision of calibration directly decides the level of development and application of the instrument. Considering the characteristic of large field, wide wavelength range, high spatial and spectral resolution of the space-borne differential optical absorption spectrometer, a spectral calibration method is presented, a calibration device was built, the equation of spectral calibration was calculated through peak searching and regression analysis, and finally the full field spectral calibration of the instrument was realized. The precision of spectral calibration was verified with Fraunhofer lines of solar light. PMID:23387142

  14. Spectrometer system using a modular echelle spectrograph and a laser-driven continuum source for simultaneous multi-element determination by graphite furnace absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Geisler, Sebastian; Okruss, Michael; Becker-Ross, Helmut; Huang, Mao Dong; Esser, Norbert; Florek, Stefan

    2015-05-01

    A multi-element absorption spectrometer system has been developed based on a laser-driven xenon continuum source and a modular simultaneous echelle spectrograph (MOSES), which is characterized by a minimized number of optical components resulting in high optical throughput, high transmittance and high image quality. The main feature of the new optical design is the multifunction usage of a Littrow prism, which is attached on a rotation stage. It operates as an order-sorter for the echelle grating in a double-pass mode, as a fine positioning device moving the echelle spectrum on the detector, and as a forwarder to address different optical components, e.g., echelle gratings, in the setup. Using different prisms, which are mounted back to back on the rotation stage, a multitude of different spectroscopic modes like broad-range panorama observations, specific UV-VIS and NIR studies or high resolution zoom investigations of variable spectral channels can be realized. In the UV panorama mode applied in this work, MOSES has simultaneously detectable wavelength coverage from 193 nm to 390 nm with a spectral resolution λ/Δλ of 55,000 (3-pixel criterion). In the zoom mode the latter can be further increased by a factor of about two for a selectable section of the full wavelength range. The applicability and the analytical performance of the system were tested by simultaneous element determination in a graphite furnace, using eight different elements. Compared to an instrument operating in the optimized single line mode, the achieved analytical sensitivity using the panorama mode was typically a factor of two lower. Using the zoom mode for selected elements, comparable sensitivities were obtained. The results confirm the influence of the different spectral resolutions.

  15. A Fourier transform spectrometer for visible and near ultra-violet measurements of atmospheric absorption

    NASA Technical Reports Server (NTRS)

    Parsons, C. L.; Gerlach, J. C.; Whitehurst, M.

    1982-01-01

    The development of a prototype, ground-based, Sun-pointed Michelson interferometric spectrometer is described. Its intended use is to measure the atmospheric amount of various gases which absorb in the near-infrared, visible, and near-ultraviolet portions of the electromagnetic spectrum. Preliminary spectra which contain the alpha, 0.8 micrometer, and rho sigma tau water vapor absorption bands in the near-infrared are presented to indicate the present capability of the system. Ultimately, the spectrometer can be used to explore the feasible applications of Fourier transform spectroscopy in the ultraviolet where grating spectrometers were used exclusively.

  16. A decay total absorption spectrometer for DESPEC at FAIR

    NASA Astrophysics Data System (ADS)

    Tain, J. L.; Algora, A.; Agramunt, J.; Guadilla, V.; Jordan, M. D.; Montaner-Pizá, A.; Rubio, B.; Valencia, E.; Cano-Ott, D.; Gelletly, W.; Martinez, T.; Mendoza, E.; Podolyák, Zs.; Regan, P.; Simpson, J.; Smith, A. J.; Strachan, J.

    2015-12-01

    This paper presents the design of a total absorption γ-ray spectrometer for the determination of β-decay intensity distributions of exotic nuclear species at the focal plane of the FAIR-NUSTAR Super Fragment Separator. The spectrometer is a key instrument in the DESPEC experiment and the proposed implementation follows extensive design studies and prototype tests. Two options were contemplated, based on NaI(Tl) and LaBr3:Ce inorganic scintillation crystals respectively. Monte Carlo simulations and technical considerations determined the optimal configurations consisting of sixteen 15 × 15 × 25cm3 crystals for the NaI(Tl) option and one hundred and twenty-eight 5.5 × 5.5 × 11cm3 crystals for the LaBr3:Ce option. Minimization of dead material was crucial for maximizing the spectrometer full-energy peak efficiency. Module prototypes were build to verify constructional details and characterize their performance. The measured energy and timing resolution was found to agree rather well with estimates based on simulations of scintillation light transport and collection. The neutron sensitivity of the spectrometer, important when measuring β-delayed neutron emitters, was investigated by means of Monte Carlo simulations.

  17. Tracking System for Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Johnson, R. A.; Webster, C. R.; Menzies, R. T.; Morrison, G. B.; Riccio, J. H.

    1986-01-01

    Visible laser tracking system for infrared laser spectometer keeps probe infrared laser beam aimed at moving reflector, thereby keeping reflector image and return laser beam within spectrometer field of view. System includes tracking mirror tilted by stepping motors under microprocessor control to deflect beams toward continually changing reflector position.

  18. The parameters of the full absorption neutron spectrometer

    NASA Astrophysics Data System (ADS)

    Filchenkov, V. V.; Konin, A. D.; Rudenko, A. I.

    1990-09-01

    The methods of obtaining the parameters of the full absorption neutron spectrometer constructed in JINR [V.P. Dzhelepov et al., Nucl. Instr. and Meth. A269 (1988) 634] (full scintillator volume V=24 1) and used in experiments studying the muon catalysis process are considered. These parameters have been obtained from the analysis of pulse-height distributions measured with γ-sources of different energies and with neutrons selected from the 238PuBe spectrum using the TOF method. A value of σ FWHM=0.09(1+ {1}/{√E e( MeV) } has been obtained for the pulse-height resolution. It is two times better than that obtained for a detector [G. Dietze and H. Klein, Nucl. Instr. and Meth. 193 (1982) 549] of smaller size. The threshold energy for n-γ separation Eγthr≅50keV, which corresponds to the best results obtained with small detectors.

  19. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  20. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  1. Automated extraction of absorption features from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and Geophysical and Environmental Research Imaging Spectrometer (GERIS) data

    NASA Technical Reports Server (NTRS)

    Kruse, Fred A.; Calvin, Wendy M.; Seznec, Olivier

    1988-01-01

    Automated techniques were developed for the extraction and characterization of absorption features from reflectance spectra. The absorption feature extraction algorithms were successfully tested on laboratory, field, and aircraft imaging spectrometer data. A suite of laboratory spectra of the most common minerals was analyzed and absorption band characteristics tabulated. A prototype expert system was designed, implemented, and successfully tested to allow identification of minerals based on the extracted absorption band characteristics. AVIRIS spectra for a site in the northern Grapevine Mountains, Nevada, have been characterized and the minerals sericite (fine grained muscovite) and dolomite were identified. The minerals kaolinite, alunite, and buddingtonite were identified and mapped for a site at Cuprite, Nevada, using the feature extraction algorithms on the new Geophysical and Environmental Research 64 channel imaging spectrometer (GERIS) data. The feature extraction routines (written in FORTRAN and C) were interfaced to the expert system (written in PROLOG) to allow both efficient processing of numerical data and logical spectrum analysis.

  2. Automated mass spectrometer analysis system

    NASA Technical Reports Server (NTRS)

    Kuppermann, Aron (Inventor); Dreyer, William J. (Inventor); Giffin, Charles E. (Inventor); Boettger, Heinz G. (Inventor)

    1982-01-01

    An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatilizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vilicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

  3. Automated mass spectrometer analysis system

    NASA Technical Reports Server (NTRS)

    Boettger, Heinz G. (Inventor); Giffin, Charles E. (Inventor); Dreyer, William J. (Inventor); Kuppermann, Aron (Inventor)

    1978-01-01

    An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vidicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

  4. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  5. Chaotic Systems with Absorption

    NASA Astrophysics Data System (ADS)

    Altmann, Eduardo G.; Portela, Jefferson S. E.; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions Dq obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D1 in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  6. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  7. Chaotic systems with absorption.

    PubMed

    Altmann, Eduardo G; Portela, Jefferson S E; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions D(q) obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D(1) in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results. PMID:24138240

  8. Ultra High Mass Range Mass Spectrometer System

    DOEpatents

    Reilly, Peter T. A. [Knoxville, TN

    2005-12-06

    Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.

  9. Sonic spectrometer and treatment system

    DOEpatents

    Slomka, Bogdan J.

    1997-06-03

    A novel system and method for treating an object with sonic waveforms. A traveling broad-band sonic waveform containing a broad-band of sonic frequencies is radiated at the object. A traveling reflected sonic waveform containing sonic frequencies reflected by the object is received in response to the traveling broad-band sonic waveform. A traveling transmitted sonic waveform containing sonic frequencies transmitted through the object is also received in response to the traveling broad-band sonic waveform. In a resonance mode, the frequency spectra of the broad-band and reflected sonic waveforms is analyzed so as to select one or more sonic frequencies that cause the object to resonate. An electrical resonance treatment sonic waveform containing the sonic frequencies that cause the object to resonate is then radiated at the object so as to treat the object. In an absorption mode, the frequency spectra of the electrical broad-band, reflected, and transmitted sonic waveforms is compared so as to select one or more sonic frequencies that are absorbed by the object. An electrical absorption treatment sonic waveform containing the sonic frequencies that are absorbed by the object is then radiated at the object so as to treat the object.

  10. Sonic spectrometer and treatment system

    DOEpatents

    Slomka, B.J.

    1997-06-03

    A novel system and method is developed for treating an object with sonic waveforms. A traveling broad-band sonic waveform containing a broad-band of sonic frequencies is radiated at the object. A traveling reflected sonic waveform containing sonic frequencies reflected by the object is received in response to the traveling broad-band sonic waveform. A traveling transmitted sonic waveform containing sonic frequencies transmitted through the object is also received in response to the traveling broad-band sonic waveform. In a resonance mode, the frequency spectra of the broad-band and reflected sonic waveforms is analyzed so as to select one or more sonic frequencies that cause the object to resonate. An electrical resonance treatment sonic waveform containing the sonic frequencies that cause the object to resonate is then radiated at the object so as to treat the object. In an absorption mode, the frequency spectra of the electrical broad-band, reflected, and transmitted sonic waveforms is compared so as to select one or more sonic frequencies that are absorbed by the object. An electrical absorption treatment sonic waveform containing the sonic frequencies that are absorbed by the object is then radiated at the object so as to treat the object. 1 fig.

  11. Gas sampling system for a mass spectrometer

    DOEpatents

    Taylor, Charles E; Ladner, Edward P

    2003-12-30

    The present invention relates generally to a gas sampling system, and specifically to a gas sampling system for transporting a hazardous process gas to a remotely located mass spectrometer. The gas sampling system includes a capillary tube having a predetermined capillary length and capillary diameter in communication with the supply of process gas and the mass spectrometer, a flexible tube surrounding and coaxial with the capillary tube intermediate the supply of process gas and the mass spectrometer, a heat transfer tube surrounding and coaxial with the capillary tube, and a heating device in communication the heat transfer tube for substantially preventing condensation of the process gas within the capillary tube.

  12. MICE Spectrometer Magnet System Progress

    SciTech Connect

    Green, Michael A.; Virostek, Steve P.

    2007-08-27

    The first magnets for the muon ionization cooling experimentwill be the tracker solenoids that form the ends of the MICE coolingchannel. The primary purpose of the tracker solenoids is to provide auniform 4 T field (to better than +-0.3 percent over a volume that is 1meter long and 0.3 meters in diameter) spectrometer magnet field for thescintillating fiber detectors that are used to analyze the muons in thechannel before and after ionization cooling. A secondary purpose for thetracker magnet is the matching of the muon beam between the rest of theMICE cooling channel and the uniform field spectrometer magnet. Thetracker solenoid is powered by three 300 amp power supplies. Additionaltuning of the spectrometer is provided by a pair of 50 amp power suppliesacross the spectrometer magnet end coils. The tracker magnet will becooled using a pair of 4 K pulse tube coolers that each provide 1.5 W ofcooling at 4.2 K. Final design and construction of the tracker solenoidsbegan during the summer of 2006. This report describes the progress madeon the construction of the tracker solenoids.

  13. A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer

    SciTech Connect

    Leone, Stephen; Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E.; Leone, Stephen R.

    2008-05-21

    A laser-based, table-top instrument is constructed to perform femtosecond soft x-ray transient absorption spectroscopy. Ultrashort soft x-ray pulses produced via high-order harmonic generation of the amplified output of a femtosecond Ti:sapphire laser system are used to probe atomic core-level transient absorptions in atoms and molecules. The results provide chemically specific, time-resolved dynamics with sub-50-fs time resolution. In this setup, high-order harmonics generated in a Ne-filled capillary waveguide are refocused by a gold-coated toroidal mirror into the sample gas cell, where the soft x-ray light intersects with an optical pump pulse. The transmitted high-order harmonics are spectrally dispersed with a home-built soft x-ray spectrometer, which consists of a gold-coated toroidal mirror, a uniform-line spaced plane grating, and a soft x-ray CCD camera. The optical layout of the instrument, design of the soft x-ray spectrometer, and spatial and temporal characterization of the high-order harmonics are described. Examples of static and time-resolved photoabsorption spectra collected on this apparatus are presented.

  14. Evaluation of Small Mass Spectrometer Systems

    NASA Technical Reports Server (NTRS)

    Arkin, C. Richard; Griffin, Timothy P.; Ottens, Andrew K.; Diaz, Jorge A.; Follistein, Duke W.; Adams, Fredrick W.; Helms, William R.; Voska, N. (Technical Monitor)

    2002-01-01

    Various mass analyzer systems were evaluated. Several systems show promise, including the Stanford Research Systems RGA-100, Inficon XPR-2, the University of Florida's Ion Trap, and the Compact Double Focus Mass Spectrometer. Areas that need improvement are the response time, recovery time, system volume, and system weight. Future work will investigate techniques to improve systems and will evaluate engineering challenges.

  15. Cavity ring-down spectrometer for high-fidelity molecular absorption measurements

    NASA Astrophysics Data System (ADS)

    Lin, H.; Reed, Z. D.; Sironneau, V. T.; Hodges, J. T.

    2015-08-01

    We present a cavity ring-down spectrometer which was developed for near-infrared measurements of laser absorption by atmospheric greenhouse gases. This system has several important attributes that make it possible to conduct broad spectral surveys and to determine line-by-line parameters with wide dynamic range, and high spectral resolution, sensitivity and accuracy. We demonstrate a noise-equivalent absorption coefficient of 4×10-12 cm-1 Hz-1/2 and a signal-to-noise ratio of 1.5×106:1 in an absorption spectrum of carbon monoxide. We also present high-resolution measurements of trace methane in air spanning more than 1.2 THz and having a frequency axing with an uncertainty less than 100 kHz. Finally, we discuss how this system enables stringent tests of advanced line shape models. To illustrate, we measured an air-broadened carbon dioxide transition over a wide pressure range and analyzed these data with a multi-spectrum fit of the partially correlated, quadratic speed-dependent Nelkin-Ghatak profile. We obtained a quality-of-fit parameter in the multispectrum fit equal to 36,000, thus quantifying small-but-measurable limitations of the model profile. This analysis showed that the line shape depends upon collisional narrowing, speed dependent effects and partial correlations between velocity- and phase-changing collisions.

  16. DUVAS (derivative uv-absorption spectrometer): instrument description and operating manual

    SciTech Connect

    Hawthorne, A.R.; Dougherty, J.M.; Metcalfe, C.E.

    1980-11-01

    DUVAS is a real-time, field-portable spectrometer capable of monitoring a variety of aromatic organic vapors and inorganic gases at sub-ppM concentrations. The instrument is a prototype, microcomputer-controlled, derivative ultraviolet (UV) absorption spectrometer (DUVAS) developed primarily for area monitoring at coal conversion facilities, although other important occupational and environmental monitoring applications for compounds such as SO/sub 2/, NO/sub x/, NH/sub 3/, and HCHO are also being pursued.

  17. Aerosol absorption measurement at SWIR with water vapor interference using a differential photoacoustic spectrometer.

    PubMed

    Zhu, Wenyue; Liu, Qiang; Wu, Yi

    2015-09-01

    Atmospheric aerosol plays an important role in atmospheric radiation balance through absorbing and scattering the solar radiation, which changes local weather and global climate. Accurate measurement is highly requested to estimate the radiative effects and climate effects of atmospheric aerosol. Photoacoustic spectroscopy (PAS) technique, which observes the aerosols on their natural suspended state and is insensitive to light scattering, is commonly recognized as one of the best candidates to measure the optical absorption coefficient (OAC) of aerosols. In the present work, a method of measuring aerosol OAC at the wavelength where could also be absorbed by water vapor was proposed and corresponding measurements of the absorption properties of the atmospheric aerosol at the short wave infrared (SWIR, 1342 nm) wavelength were carried out. The spectrometer was made up of two high performance homemade photoacoustic cells. To improve the sensitivity, several methods were presented to control the noise derived from gas flow and vibration from the sampling pump. Calibration of the OAC and properties of the system were also studied in detail. Using the established PAS instrument, measurement of the optical absorption properties of the atmospheric aerosol were carried out in laboratory and field environment. PMID:26368414

  18. Further developments of capillary absorption spectrometers using small hollow-waveguide fibers

    SciTech Connect

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.; Kriesel, Jason M.

    2014-05-01

    Our objective is to enhance quantification of stable carbon and oxygen isotope ratios to better than 1‰ relative isotope precision for sample sizes < 1 pico-mole. A newer variant Capillary Absorption Spectrometer (CAS) is described using a proprietary linear-taper hollow waveguide in conjunction with wavelength and frequency modulation techniques of tunable laser absorption spectrometry. Previous work used circular capillaries with uniform 1 mm ID to measure 13C/12C ratios with ≥ 20 pico-mole samples to ≤ 10 ppm (1‰ precision against standards) [1]. While performing fairly well, it generated residual modal noise due to multipath propagation in the hollow-waveguides (HWGs). This system has been utilized with laser ablation-catalytic combustion techniques to analyze small resolution (~ 25 μm spot diameter) laser ablation events on solids. Using smaller ID capillary waveguides could improve detection limits and spatial resolutions. Reducing an IR compatible hollow waveguide’s inner diameter (ID) to < 300 μm, reduces modal noise significantly for mid-IR operation, but feedback noise with high gain semiconductor lasers can become problematic. A proprietary linear-taper small waveguide (mean ID = 0.35 mm, L = 1 m) was tested to understand whether modal noise and optical feedback effects could be simultaneously reduced. We see better mode filtering and, significant reductions of feedback noise under favorable coupling of a multi-spatial mode QC laser to the smaller ID of the linear-tapered HWG. We demonstrate that better modal coupling operation is consistent with Liouville’s theorem, where greater suppression of feedback from spurious scatter within the HWG occurs by injecting the laser into the smaller ID port. Our progress on developing lighter weight, potentially fieldable alternatives to Isotope Ratio Mass Spectrometers (IRMS) with a small volume (≤ 0.1 cm3) CAS system will be discussed and compared to other competitive systems.

  19. FTIR-spectrometer-determined absorption coefficients of seven hydrazine fuel gases - Implications for laser remote sensing

    NASA Technical Reports Server (NTRS)

    Molina, L. T.; Grant, W. B.

    1984-01-01

    The absorption spectra of three hydrazines and four of their air-oxidation products were measured in the 9-12-micron spectral region with a Fourier transform infrared (FTIR) spectrometer with a 0.05-kayser resolution to determine absorption coefficients at CO2 and tunable diode laser wavelengths. The measurements agreed well with published CO2 laser determinations for many of the absorption coefficients, except where the published values are thought to be in error. The coefficients were then used to estimate the sensitivity for remote detection of these gases using CO2 and tunable diode lasers in long-path differential absorption measurements.

  20. Sensitive absorption measurements in bulk material and coatings using a photothermal and a photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Fieberg, S.; Waasem, N.; Kühnemann, F.; Buse, K.

    2014-02-01

    Bulk and surface absorption in lithium triborate (LBO) and lithium niobate (LiNbO3) are measured using two sensitive measurement techniques, a photoacoustic spectrometer (PAS) and a photothermal common-path interferometer (PCI). As pump light sources, optical parametric oscillators are employed, covering the wavelength ranges 212 - 2500 nm (PAS) and 1460 - 1900 nm and 2460 - 3900 nm (PCI). The spectrometers are used to measure absorption spectra of optical materials across this wide spectral range and to compare the methods in the shared wavelength regime.

  1. Spectral calibration for infrared hyperspectral imaging Fourier transform spectrometer based on absorption peaks

    NASA Astrophysics Data System (ADS)

    Li, YaSheng; Chen, Yan; Liao, Ningfang; Lyu, Hang; He, Shufang; Wan, Lifang

    2015-08-01

    A new calibration method for infrared hyperspectral imaging Fourier transform spectrometer is presented. Two kinds of common materials as Polypropylene (PP) and Polyethylene Terephthalate (PET) films which have special absorption peaks in the infrared band were used in the calibration experiment. As the wavelengths at the sharp absorption peaks of the films are known, an infrared imaging spectrometer can be calibrated on spectra with two or three peaks. With high precision and stability, this method simplifies the calibration work. It is especially appropriate for the measuring condition with a lack of calibration equipment or with inconvenience to calibrate the multiple light sources outdoors.

  2. A high resolution x-ray fluorescence spectrometer for near edge absorption studies

    SciTech Connect

    Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

    1991-01-01

    A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

  3. A high resolution x-ray fluorescence spectrometer for near edge absorption studies

    SciTech Connect

    Stojanoff, V.; Hamalainen, K.; Siddons, D.P.; Hastings, J.B.; Berman, L.E.; Cramer, S.; Smith, G.

    1991-12-31

    A high resolution fluorescence spectrometer using a Johann geometry in a back scattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near edge absorption spectrum of dysprosium nitrate. 10 refs., 4 figs.

  4. Lens system for a photo ion spectrometer

    DOEpatents

    Gruen, D.M.; Young, C.E.; Pellin, M.J.

    1990-11-27

    A lens system in a photo ion spectrometer for manipulating a primary ion beam and ionized atomic component is disclosed. The atomic components are removed from a sample by a primary ion beam using the lens system, and the ions are extracted for analysis. The lens system further includes ionization resistant coatings for protecting the lens system. 8 figs.

  5. Lens system for a photo ion spectrometer

    DOEpatents

    Gruen, Dieter M.; Young, Charles E.; Pellin, Michael J.

    1990-01-01

    A lens system in a photo ion spectrometer for manipulating a primary ion beam and ionized atomic component. The atomic components are removed from a sample by a primary ion beam using the lens system, and the ions are extracted for analysis. The lens system further includes ionization resistant coatings for protecting the lens system.

  6. An off Axis Cavity Enhanced Absorption Spectrometer and a Rapid Scan Spectrometer with a Room-Temperature External Cavity Quantum Cascade Laser

    NASA Astrophysics Data System (ADS)

    Liu, Xunchen; Kang, Cheolhwa; Xu, Yunjie

    2009-06-01

    Quantum cascade laser (QCL) is a new type of mid-infrared tunable diode lasers with superior output power and mode quality. Recent developments, such as room temperature operation, wide frequency tunability, and narrow line width, make QCLs an ideal light source for high resolution spectroscopy. Two slit jet infrared spectrometers, namely an off-axis cavity enhanced absorption (CEA) spectrometer and a rapid scan spectrometer with an astigmatic multi-pass cell assembly, have been coupled with a newly purchased room temperature tunable mod-hop-free QCL with a frequency coverage from 1592 cm^{-1} to 1698 cm^{-1} and a scan rate of 0.1 cm^{-1}/ms. Our aim is to utilize these two sensitive spectrometers, that are equipped with a molecular jet expansion, to investigate the chiral molecules-(water)_n clusters. To demonstrate the resolution and sensitivity achieved, the rovibrational transitions of the static N_2O gas and the bending rovibrational transitions of the Ar-water complex, a test system, at 1634 cm^{-1} have been measured. D. Hofstetter and J. Faist in High performance quantum cascade lasers and their applications, Vol.89 Springer-Verlag Berlin & Heidelberg, 2003, pp. 61-98. Y. Xu, X. Liu, Z. Su, R. M. Kulkarni, W. S. Tam, C. Kang, I. Leonov and L. D'Agostino, Proc. Spie, 2009, 722208 (1-11). M. J. Weida and D. J. Nesbitt, J. Chem. Phys. 1997, 106, 3078-3089.

  7. Design and performance of a tunable diode laser absorption spectrometer for airborne formaldehyde measurements

    NASA Astrophysics Data System (ADS)

    Wert, B. P.; Fried, A.; Rauenbuehler, S.; Walega, J.; Henry, B.

    2003-06-01

    A tunable diode laser absorption spectrometer (TDLAS) was modified for high-precision and high-time-resolution formaldehyde (CH2O) measurements. This enhanced system was deployed in both the clean and polluted troposphere, as part of aircraft missions (TOPSE 2000, TexAQS 2000, and TRACE-P 2001) and ground-based missions (SOS 1999). Measurements of very constant ambient CH2O concentrations were used to determine instrument precisions, which were stable under normal operating conditions, with the exception of brief aircraft cabin pressure changes. Precisions of 15-50 pptv (1σ) were typically achieved for 1 min of averaging, corresponding to absorptions of 0.5-1.7 × 10-6, 3-5 times better than the previous version of the instrument (1998). Responsible modifications included improved temperature and pressure control of instrument components and the use of more stable optical mounts. During the TexAQS 2000 aircraft mission (polluted continental troposphere), measurements of 1 s time resolution were reported. Instrument accuracy was validated by calibration cross checks, interference tests, sample transmission tests, and field comparisons with a DOAS system.

  8. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2015-10-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light emitting diodes (LEDs) and a grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high power LEDs with electronic on/off modulation, state-of-the-art cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350 and 80 pptv in 5 s. The accuracy is 5.8, 9.0 and 5.0 % limited mainly by the available absorption cross sections.

  9. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2016-02-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

  10. Trace gas absorption spectroscopy using laser difference-frequency spectrometer for environmental application

    NASA Technical Reports Server (NTRS)

    Chen, W.; Cazier, F.; Boucher, D.; Tittel, F. K.; Davies, P. B.

    2001-01-01

    A widely tunable infrared spectrometer based on difference frequency generation (DFG) has been developed for organic trace gas detection by laser absorption spectroscopy. On-line measurements of concentration of various hydrocarbons, such as acetylene, benzene, and ethylene, were investigated using high-resolution DFG trace gas spectroscopy for highly sensitive detection.

  11. The laser absorption spectrometer - A new remote sensing instrument for atmospheric pollution monitoring

    NASA Technical Reports Server (NTRS)

    Shumate, M. S.

    1974-01-01

    An instrument capable of remotely monitoring trace atmospheric constituents is described. The instrument, called a laser absorption spectrometer, can be operated from an aircraft or spacecraft to measure the concentration of selected gases in three dimensions. This device will be particularly useful for rapid determination of pollutant levels in urban areas.

  12. AIR QUALITY MONITORING IN ATLANTA WITH THE DIFFERENTIAL OPTICAL ABSORPTION SPECTROMETER

    EPA Science Inventory

    During July and August of 1990, a differential optical absorption spectrometer (DOAS) made by OPSIS Inc. was used to measure gaseous air pollutants over three separate open paths in Atlanta, GA. ver path 1 (1099 m) and path 2 (1824 m), ozone (O3), sulfur dioxide (SO2), nitrogen d...

  13. Expert system for imaging spectrometer analysis results

    NASA Technical Reports Server (NTRS)

    Borchardt, Gary C.

    1985-01-01

    Information on an expert system for imaging spectrometer analysis results is outlined. Implementation requirements, the Simple Tool for Automated Reasoning (STAR) program that provides a software environment for the development and operation of rule-based expert systems, STAR data structures, and rule-based identification of surface materials are among the topics outlined.

  14. Search for molecular absorptions with the Fourier Transform Spectrometer

    NASA Technical Reports Server (NTRS)

    Knacke, Roger F.

    1995-01-01

    The objective of this research was a search for water molecules in the gas phase in molecular clouds. Water should be among the most abundant gases in the clouds and is of fundamental importance in gas chemistry, cloud cooling, shock wave chemistry, and gas-grain interactions of interstellar dust. Detection of water in Comet Halley in the 2.7 micron v(3) band in 1986 had shown that airborne H2O observations are feasible (ground-based observations of H2O are impossible because of the massive water content of the atmosphere). We planned to observe the v(3) band in interstellar clouds where a number of lines of this band should be in absorption. The search for H2O commenced in 1988 with a two flight program on the KAO. this resulted in a detection of interstellar H2O with S/N of 2-4 in the v(3) 1(01)-2(02) line at 3801.42/cm. A subsequent flight series of two flights in 1989 resulted in confirmation to the 3801.42/cm line detection and the detection of altogether four strong lines in the 000-001 v(3) vibration-rotation band of H2O.

  15. The airborne Laser Absorption Spectrometer - A new instrument of remote measurement of atmospheric trace gases

    NASA Technical Reports Server (NTRS)

    Shumate, M. S.; Menzies, R. T.

    1978-01-01

    The Laser Absorption Spectrometer is a portable instrument developed by JPL for remote measurement of trace gases from an aircraft platform. It contains two carbon dioxide lasers, two optical heterodyne receivers, appropriate optics to aim the lasers at the ground and detect the backscattered energy, and signal processing and recording electronics. Operating in the differential-absorption mode, it is possible to monitor one atmospheric gas at a time and record the data in real time. The system can presently measure ozone, ethylene, water vapor, and chlorofluoromethanes with high sensitivity. Airborne measurements were made in early 1977 from the NASA/JPL twin-engine Beechcraft and in May 1977 from the NASA Convair 990 during the ASSESS-II Shuttle Simulation Study. These flights resulted in measurements of ozone concentrations in the lower troposphere which were compared with ground-based values provided by the Air Pollution Control District. This paper describes the details of the instrument and results of the airborne measurements.

  16. Airborne Carbon Dioxide Laser Absorption Spectrometer for IPDA Measurements of Tropospheric CO2: Recent Results

    NASA Technical Reports Server (NTRS)

    Spiers, Gary D.; Menzies, Robert T.

    2008-01-01

    The National Research Council's decadal survey on Earth Science and Applications from Space[1] recommended the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission for launch in 2013-2016 as a logical follow-on to the Orbiting Carbon Observatory (OCO) which is scheduled for launch in late 2008 [2]. The use of a laser absorption measurement technique provides the required ability to make day and night measurements of CO2 over all latitudes and seasons. As a demonstrator for an approach to meeting the instrument needs for the ASCENDS mission we have developed the airborne Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) which uses the Integrated Path Differential Absorption (IPDA) Spectrometer [3] technique operating in the 2 micron wavelength region.. During 2006 a short engineering checkout flight of the CO2LAS was conducted and the results presented previously [4]. Several short flight campaigns were conducted during 2007 and we report results from these campaigns.

  17. Note: A flexible light emitting diode-based broadband transient-absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Gottlieb, Sean M.; Corley, Scott C.; Madsen, Dorte; Larsen, Delmar S.

    2012-05-01

    This Note presents a simple and flexible ns-to-ms transient absorption spectrometer based on pulsed light emitting diode (LED) technology that can be incorporated into existing ultrafast transient absorption spectrometers or operate as a stand-alone instrument with fixed-wavelength laser sources. The LED probe pulses from this instrument exhibit excellent stability (˜0.5%) and are capable of producing high signal-to-noise long-time (>100 ns) transient absorption signals either in a broadband multiplexed (spanning 250 nm) or in tunable narrowband (20 ns) operation. The utility of the instrument is demonstrated by measuring the photoinduced ns-to-ms photodynamics of the red/green absorbing fourth GMP phosphodiesterase/adenylyl cyclase/FhlA domain of the NpR6012 locus of the nitrogen-fixing cyanobacterium Nostoc punctiforme.

  18. Sensing systems using chip-based spectrometers

    NASA Astrophysics Data System (ADS)

    Nitkowski, Arthur; Preston, Kyle J.; Sherwood-Droz, Nicolás.; Behr, Bradford B.; Bismilla, Yusuf; Cenko, Andrew T.; DesRoches, Brandon; Meade, Jeffrey T.; Munro, Elizabeth A.; Slaa, Jared; Schmidt, Bradley S.; Hajian, Arsen R.

    2014-06-01

    Tornado Spectral Systems has developed a new chip-based spectrometer called OCTANE, the Optical Coherence Tomography Advanced Nanophotonic Engine, built using a planar lightwave circuit with integrated waveguides fabricated on a silicon wafer. While designed for spectral domain optical coherence tomography (SD-OCT) systems, the same miniaturized technology can be applied to many other spectroscopic applications. The field of integrated optics enables the design of complex optical systems which are monolithically integrated on silicon chips. The form factors of these systems can be significantly smaller, more robust and less expensive than their equivalent free-space counterparts. Fabrication techniques and material systems developed for microelectronics have previously been adapted for integrated optics in the telecom industry, where millions of chip-based components are used to power the optical backbone of the internet. We have further adapted the photonic technology platform for spectroscopy applications, allowing unheard-of economies of scale for these types of optical devices. Instead of changing lenses and aligning systems, these devices are accurately designed programmatically and are easily customized for specific applications. Spectrometers using integrated optics have large advantages in systems where size, robustness and cost matter: field-deployable devices, UAVs, UUVs, satellites, handheld scanning and more. We will discuss the performance characteristics of our chip-based spectrometers and the type of spectral sensing applications enabled by this technology.

  19. Micro-optical-mechanical system photoacoustic spectrometer

    DOEpatents

    Kotovsky, Jack; Benett, William J.; Tooker, Angela C.; Alameda, Jennifer B.

    2013-01-01

    All-optical photoacoustic spectrometer sensing systems (PASS system) and methods include all the hardware needed to analyze the presence of a large variety of materials (solid, liquid and gas). Some of the all-optical PASS systems require only two optical-fibers to communicate with the opto-electronic power and readout systems that exist outside of the material environment. Methods for improving the signal-to-noise are provided and enable mirco-scale systems and methods for operating such systems.

  20. Characterization of a new modular decay total absorption gamma-ray spectrometer (DTAS) for FAIR

    SciTech Connect

    Montaner Piza, A.; Tain, J. L.; Agramunt, J.; Algora, A.; Guadilla, V.; Marin, E.; Rice, S.; Rubio, B.

    2013-06-10

    Beta-decay studies are one of the main goals of the DEcay SPECtroscopy experiment (DESPEC) to be installed at the future Facility for Antiproton and Ion Research (FAIR). DESPEC aims at the study of nuclear structure of exotic nuclei. A new modular Decay Total Absorption gamma-ray Spectrometer (DTAS) is being built at IFIC and is specially adapted to studies at fragmentation facilities such as the Super Fragment Separator (Super-FRS) at FAIR. The designed spectrometer is composed of 16 identical NaI(Tl) scintillation crystals. This work focuses on the characterization of these independent modules, as an initial step for the characterization of the full spectrometer. Monte Carlo simulations have been performed in order to understand the detector response.

  1. Cryogenic system for a superconducting spectrometer

    SciTech Connect

    Porter, J.

    1983-03-01

    The Heavy Ion Spectrometer System (HISS) relies upon superconducting coils of cryostable, pool boiling design to provide a maximum particle bending field of 3 tesla. This paper describes the cryogenic facility including helium refrigeration, gas management, liquid nitrogen system, and the overall control strategy. The system normally operates with a 4 K heat load of 150 watts; the LN/sub 2/ circuits absorb an additional 4000 watts. 80K intercept control is by an LSI 11 computer. Total available refrigeration at 4K is 400 watts using reciprocating expanders at the 20K and 4K level. The minicomputer has the capability of optimizing overall utility input cost by varying operating points. A hybrid of pneumatic, analog, and digital control is successful in providing full time unattended operation. The 7m diameter magnet/cryostat assembly is rotatable through 180 degrees to provide a variety of spectrometer orientations.

  2. Capillary absorption spectrometer and process for isotopic analysis of small samples

    DOEpatents

    Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

    2016-03-29

    A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

  3. Characterization of a Photoacoustic Aerosol Absorption Spectrometer for Aircraft-based Measurements

    NASA Astrophysics Data System (ADS)

    Mason, B. J.; Wagner, N. L.; Richardson, M.; Brock, C. A.; Murphy, D. M.; Adler, G.

    2015-12-01

    Atmospheric aerosol directly impacts the Earth's climate through extinction of incoming and outgoing radiation. The optical extinction is due to both scattering and absorption. In situ measurements of aerosol extinction and scattering are well established and have uncertainties less than 5%. However measurements of aerosol absorption typically have uncertainties of 20-30%. Development and characterization of more accurate and precise instrumentation for measurement of aerosol absorption will enable a deeper understand of significance and spatial distribution of black and brown carbon aerosol, the effect of atmospheric processes on aerosol optical properties, and influence of aerosol optical properties on direct radiative forcing. Here, we present a detailed characterization of a photoacoustic aerosol absorption spectrometer designed for deployment aboard research aircraft. The spectrometer operates at three colors across the visible spectrum and is calibrated in the field using ozone. The field calibration is validated in the laboratory using synthetic aerosol and simultaneous measurements of extinction and scattering. In addition, the sensitivity of the instrument is characterized under conditions typically encountered during aircraft sampling e.g. as a function of changing pressure. We will apply this instrument characterization to ambient aerosol absorption data collected during the SENEX and SEAC4RS aircraft based field campaigns.

  4. A split imaging spectrometer for temporally and spatially resolved titanium absorption spectroscopy

    SciTech Connect

    Hager, J. D. Lanier, N. E.; Kline, J. L.; Flippo, K. A.; Bruns, H. C.; Schneider, M.; Saculla, M.; McCarville, T.

    2014-11-15

    We present a temporally and a spatially resolved spectrometer for titanium x-ray absorption spectroscopy along 2 axial symmetric lines-of-sight. Each line-of-sight of the instrument uses an elliptical crystal to acquire both the 2p and 3p Ti absorption lines on a single, time gated channel of the instrument. The 2 axial symmetric lines-of-sight allow the 2p and 3p absorption features to be measured through the same point in space using both channels of the instrument. The spatially dependent material temperature can be inferred by observing the 2p and the 3p Ti absorption features. The data are recorded on a two strip framing camera with each strip collecting data from a single line-of-sight. The design is compatible for use at both the OMEGA laser and the National Ignition Facility. The spectrometer is intended to measure the material temperature behind a Marshak wave in a radiatively driven SiO{sub 2} foam with a Ti foam tracer. In this configuration, a broad band CsI backlighter will be used for a source and the Ti absorption spectrum measured.

  5. Portable 4.6 Micrometers Laser Absorption Spectrometer for Carbon Monoxide Monitoring and Fire Detection

    NASA Technical Reports Server (NTRS)

    Briggs, Ryan M.; Frez, Clifford; Forouhar, Siamak; May, Randy D.; Ruff, Gary A.

    2013-01-01

    The air quality aboard manned spacecraft must be continuously monitored to ensure crew safety and identify equipment malfunctions. In particular, accurate real-time monitoring of carbon monoxide (CO) levels helps to prevent chronic exposure and can also provide early detection of combustion-related hazards. For long-duration missions, environmental monitoring grows in importance, but the mass and volume of monitoring instruments must be minimized. Furthermore, environmental analysis beyond low-Earth orbit must be performed in-situ, as sample return becomes impractical. Due to their small size, low power draw, and performance reliability, semiconductor-laser-based absorption spectrometers are viable candidates for this purpose. To reduce instrument form factor and complexity, the emission wavelength of the laser source should coincide with strong fundamental absorption lines of the target gases, which occur in the 3 to 5 micrometers wavelength range for most combustion products of interest, thereby reducing the absorption path length required for low-level concentration measurements. To address the needs of current and future NASA missions, we have developed a prototype absorption spectrometer using a semiconductor quantum cascade laser source operating near 4.6 micrometers that can be used to detect low concentrations of CO with a compact single-pass absorption cell. In this study, we present the design of the prototype instrument and report on measurements of CO emissions from the combustion of a variety of aerospace plastics.

  6. A split imaging spectrometer for temporally and spatially resolved titanium absorption spectroscopy.

    PubMed

    Hager, J D; Lanier, N E; Kline, J L; Flippo, K A; Bruns, H C; Schneider, M; Saculla, M; McCarville, T

    2014-11-01

    We present a temporally and a spatially resolved spectrometer for titanium x-ray absorption spectroscopy along 2 axial symmetric lines-of-sight. Each line-of-sight of the instrument uses an elliptical crystal to acquire both the 2p and 3p Ti absorption lines on a single, time gated channel of the instrument. The 2 axial symmetric lines-of-sight allow the 2p and 3p absorption features to be measured through the same point in space using both channels of the instrument. The spatially dependent material temperature can be inferred by observing the 2p and the 3p Ti absorption features. The data are recorded on a two strip framing camera with each strip collecting data from a single line-of-sight. The design is compatible for use at both the OMEGA laser and the National Ignition Facility. The spectrometer is intended to measure the material temperature behind a Marshak wave in a radiatively driven SiO2 foam with a Ti foam tracer. In this configuration, a broad band CsI backlighter will be used for a source and the Ti absorption spectrum measured. PMID:25430177

  7. JPL Carbon Dioxide Laser Absorption Spectrometer Data Processing Results for the 2010 Flight Campaign

    NASA Technical Reports Server (NTRS)

    Jacob, Joseph C.; Spiers, Gary D.; Menzie, Robert T.; Christensen, Lance E.

    2011-01-01

    As a precursor to and validation of the core technology necessary for NASA's Active Sensing of CO2 Emissions over Nights, Days,and Seasons (ASCENDS) mission, we flew JPL's Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) in a campaign of five flights onboard NASA's DC-8 Airborne Laboratory in July 2010. This is the latest in a series of annual flight campaigns that began in 2006, and our first on the DC-8 aircraft.

  8. An expert system for geologic mapping with imaging spectrometers

    NASA Technical Reports Server (NTRS)

    Kruse, F. A.; Seznec, O.; Krotkov, P. M.

    1990-01-01

    Techniques have been developed for the extraction and characterization of absorption features from visible and infrared reflectance spectra and an expert system has been designed, implemented, and successfully tested that allows automated identification of minerals based on their spectral characteristics. A suite of laboratory spectra of common minerals was analyzed and the absorption band characteristics tabulated and used to develop a generalized knowledge base for analysis of the reflectance spectra. A tree hierarchy was designed to emulate the decision process followed by an experienced analyst for analysis of laboratory and field reflectance spectra and aircraft imaging spectrometer spectra. Good results were obtained with the expert system for all three types of spectra, with the critical factor in the analysis being the signal-to-noise ratio of the spectral data.

  9. Expert overseer for mass spectrometer system

    DOEpatents

    Filby, Evan E.; Rankin, Richard A.

    1991-01-01

    An expert overseer for the operation and real-time management of a mass spectrometer and associated laboratory equipment. The overseer is a computer-based expert diagnostic system implemented on a computer separate from the dedicated computer used to control the mass spectrometer and produce the analysis results. An interface links the overseer to components of the mass spectrometer, components of the laboratory support system, and the dedicated control computer. Periodically, the overseer polls these devices and as well as itself. These data are fed into an expert portion of the system for real-time evaluation. A knowledge base used for the evaluation includes both heuristic rules and precise operation parameters. The overseer also compares current readings to a long-term database to detect any developing trends using a combination of statistical and heuristic rules to evaluate the results. The overseer has the capability to alert lab personnel whenever questionable readings or trends are observed and provide a background review of the problem and suggest root causes and potential solutions, or appropriate additional tests that could be performed. The overseer can change the sequence or frequency of the polling to respond to an observation in the current data.

  10. Tunable diode laser absorption spectrometer for ground-based measurements of formaldehyde

    NASA Astrophysics Data System (ADS)

    Fried, Alan; Sewell, Scott; Henry, Bruce; Wert, Bryan P.; Gilpin, Tim; Drummond, James R.

    1997-03-01

    We describe here a sensitive tunable diode laser absorption spectrometer (TDLAS) which was employed for ambient measurements of formaldehyde (HCHO) during the 1993 Idaho Hill/Fritz Peak Photochemistry Experiment. This system incorporated many new features and approaches including a novel astigmatic Herriott sampling cell which achieves a 100-m pathlength in a 3-L volume. We also describe procedures and tests carried out to ensure high accuracy, including the verification of HCHO standards by means of four techniques. During the field campaign, ambient HCHO measurements were acquired with an average 1σ measurement precision of 0.17 ppbv employing 1-5 min integration times. When combined with a maximum systematic uncertainty of 10%, ambient HCHO concentrations around 1.5 ppbv were measured with an average total (random plus systematic) 1σ uncertainty of 15% during the field campaign. In the intervening 2 years since the field experiment, additional features have been implemented for continuous unattended operation and improved performance. Rapid background subtraction now routinely allows HCHO measurements to be acquired with replicate precisions of 0.040 to 0.056 ppbv employing a 5-min integration period. This corresponds to routine minimum detectable absorbances of 1.2 to 1.6×10-6 in an actual mobile laboratory field environment.

  11. Five-Channel Infrared Laser Absorption Spectrometer for Combustion Product Monitoring Aboard Manned Spacecraft

    NASA Technical Reports Server (NTRS)

    Briggs, Ryan M.; Frez, Clifford; Borgentun, Carl E.; Bagheri, Mahmood; Forouhar, Siamak; May, Randy D.

    2014-01-01

    Continuous combustion product monitoring aboard manned spacecraft can prevent chronic exposure to hazardous compounds and also provides early detection of combustion events. As future missions extend beyond low-Earth orbit, analysis of returned environmental samples becomes impractical and safety monitoring should be performed in situ. Here, we describe initial designs of a five-channel tunable laser absorption spectrometer to continuously monitor combustion products with the goal of minimal maintenance and calibration over long-duration missions. The instrument incorporates dedicated laser channels to simultaneously target strong mid-infrared absorption lines of CO, HCl, HCN, HF, and CO2. The availability of low-power-consumption semiconductor lasers operating in the 2 to 5 micron wavelength range affords the flexibility to select absorption lines for each gas with maximum interaction strength and minimal interference from other gases, which enables the design of a compact and mechanically robust spectrometer with low-level sensitivity. In this paper, we focus primarily on absorption line selection based on the availability of low-power single-mode semiconductor laser sources designed specifically for the target wavelength range.

  12. Absorption-heat-pump system

    DOEpatents

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  13. [Determination of sulfur in plant using a high-resolution continuum source atomic absorption spectrometer].

    PubMed

    Wang, Yu; Li, Jia-xi

    2009-05-01

    A method for the analysis of sulfur (S) in plant by molecular absorption of carbon monosulfide (CS) using a high-resolution continuum source atomic absorption spectrometer (CS AAS) with a fuel-rich air/acetylene flame has been devised. The strong CS absorption band was found around 258 nm. The half-widths of some absorption bands were of the order of picometers, the same as the common atomic absorption lines. The experimental procedure in this study provided optimized instrumental conditions (the ratio of acetylene to air, the burner height) and parameters, and researched the spectral interferences and chemical interferences. The influence of the organic solvents on the CS absorption signals and the different digestion procedures for the determination of sulfur were also investigated. The limit of detection achieved for sulfur was 14 mg x L(-1), using the CS wavelength of 257. 961 nm and a measurement time of 3 s. The accuracy and precision were verified by analysis of two plant standard reference materials. The major applications of this method have been used for the determination of sulfur in plant materials, such as leaves. Compared to the others, this method for the analysis of sulfur is rapid, easy and simple for sulfur determination in plant. PMID:19650504

  14. Capillary Absorption Spectrometer for 13C Isotopic Composition of Pico to Subpico Molar Sample Quantities

    NASA Astrophysics Data System (ADS)

    Moran, J.; Kelly, J.; Sams, R.; Newburn, M.; Kreuzer, H.; Alexander, M.

    2011-12-01

    Quick incorporation of IR spectroscopy based isotope measurements into cutting edge research in biogeochemical cycling attests to the advantages of a spectroscopy versus mass spectrometry method for making some 13C measurements. The simple principles of optical spectroscopy allow field portability and provide a more robust general platform for isotope measurements. We present results with a new capillary absorption spectrometer (CAS) with the capability of reducing the sample size required for high precision isotopic measurements to the picomolar level and potentially the sub-picomolar level. This work was motivated by the minute sample size requirements for laser ablation isotopic studies of carbon cycling in microbial communities but has potential to be a valuable tool in other areas of biological and geological research. The CAS instrument utilizes a capillary waveguide as a sample chamber for interrogating CO2 via near IR laser absorption spectroscopy. The capillary's small volume (~ 0.5 mL) combined with propagation and interaction of the laser mode with the entire sample reduces sample size requirements to a fraction of that accessible with commercially available IR absorption including those with multi-pass or ring-down cavity systems. Using a continuous quantum cascade laser system to probe nearly adjacent rovibrational transitions of different isotopologues of CO2 near 2307 cm-1 permits sample measurement at low analyte pressures (as low as 2 Torr) for further sensitivity improvement. A novel method to reduce cw-fringing noise in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level after averaging 1,000 scans in 10 seconds. Detection limits down to the 20 picomoles have been observed, a concentration of approximately 400 ppm at 2 Torr in the waveguide with precision and accuracy at or better than 1 %. Improvements in detection and signal averaging electronics and laser power and mode quality are

  15. Infrared absorption of gaseous CH2BrOO detected with a step-scan Fourier-transform absorption spectrometer.

    PubMed

    Huang, Yu-Hsuan; Lee, Yuan-Pern

    2014-10-28

    CH2BrOO radicals were produced upon irradiation, with an excimer laser at 248 nm, of a flowing mixture of CH2Br2 and O2. A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of reaction intermediates. Transient absorption with origins at 1276.1, 1088.3, 961.0, and 884.9 cm(-1) are assigned to ν4 (CH2-wagging), ν6 (O-O stretching), ν7 (CH2-rocking mixed with C-O stretching), and ν8 (C-O stretching mixed with CH2-rocking) modes of syn-CH2BrOO, respectively. The assignments were made according to the expected photochemistry and a comparison of observed vibrational wavenumbers, relative IR intensities, and rotational contours with those predicted with the B3LYP/aug-cc-pVTZ method. The rotational contours of ν7 and ν8 indicate that hot bands involving the torsional (ν12) mode are also present, with transitions 7(0)(1)12(v)(v) and 8(0)(1)12(v)(v), v = 1-10. The most intense band (ν4) of anti-CH2BrOO near 1277 cm(-1) might have a small contribution to the observed spectra. Our work provides information for directly probing gaseous CH2BrOO with IR spectroscopy, in either the atmosphere or laboratory experiments. PMID:25362294

  16. Double tungsten coil atomic absorption spectrometer based on an acousto-optic tunable filter

    NASA Astrophysics Data System (ADS)

    Jora, M. Z.; Nóbrega, J. A.; Rohwedder, J. J. R.; Pasquini, C.

    2015-01-01

    An atomic absorption spectrometer based on a quartz acousto-optic tunable filter (AOTF) monochromator operating in the 271-453 nm range, is described. The instrument was tailored to study the formation and evolution of electrothermal atomic cloud induced either by one or two tungsten coils. The spectrometer also includes a fast response programmable photomultiplier module for data acquisition, and a power supply capable of driving two parallel tungsten coils independently. The atomization cell herein described was manufactured in PTFE and presents a new design with reduced size. Synchronization between the instant of power delivering to start the atomization process and the detection was achieved, allowing for monitoring the atomization and thermal events synchronously and in real time. Absorption signals can be sampled at a rate of a few milliseconds, compatible with the fast phenomena that occur with electrothermal metallic atomizers. The instrument performance was preliminarily evaluated by monitoring the absorption of radiation of atomic clouds produced by standard solutions containing chromium or lead. Its quantitative performance was evaluated by using Cr aqueous solutions, resulting in detection limits as low as 0.24 μg L- 1, and a relative standard deviation of 3%.

  17. The NA62 spectrometer acquisition system

    NASA Astrophysics Data System (ADS)

    Azorskiy, N.; Ceccucci, A.; Bendotti, J.; Danielsson, H.; Degrange, J.; Dixon, N.; Elsha, V.; Enik, T.; Glonti, L.; Gusakov, Y.; Kakurin, S.; Kekelidze, V.; Kislov, E.; Kolesnikov, A.; Koval, M.; Lichard, P.; Madigozhin, D.; Morant, J.; Movchan, S.; Perez Gomez, F.; Palladino, V.; Polenkevich, I.; Potrebenikov, Y.; Ruggiero, G.; Samsonov, V.; Shkarovskiy, S.; Sotnikov, A.

    2016-02-01

    The NA62 low mass spectrometer consists of 7000 straw tubes operating in vacuum. The front-end electronics is directly mounted on the detector and connected by a flexible PCB. The front-end board provides the amplification, shaping, discrimination and time measurements of the analogue signals from 16 channels. After digitisation the data is sent to a VME 9U read-out board. The data, once matched with the trigger, is sent to the next step and used by the trigger level 1 algorithm. The front-end and read-out systems of the detector will be presented along with the first results of the detector performances.

  18. Supercontinuum based absorption spectrometer for cycle-resolved multiparameter measurements in a rapid compression machine.

    PubMed

    Werblinski, Thomas; Kleindienst, Stefan; Engelbrecht, Rainer; Zigan, Lars; Will, Stefan

    2016-06-10

    A broadband supercontinuum (SC) based absorption spectrometer capable of cycle-resolved multiparameter measurements at internal combustion (IC) engine conditions is presented. Three parameters, temperature, pressure and water mole fraction, were extracted from broadband near-infrared H2O absorption spectra, spanning the wavelength-range from 1340 to 1405.5 nm, which exhibits a large number of specific H2O transitions. The spectrometer is based on spatial domain detection and features a near-infrared line scan camera as a detector. Measurements were performed during a compression cycle of a rapid compression machine comprising a pressure and temperature range from 2.5 to 65 bar and 300 to 900 K, respectively. With the new spectrometer, we are for the first time, based on the authors' knowledge, able to perform measurements based on SC radiation over a complete compression and expansion stroke at measurement rates up to 50 kHz. A detailed overview is provided about the best match algorithm between theory and experiments, including parameters from two different spectral databases, namely the Barber-Tennyson database (BT2) and HITRAN2012. The results indicate that spectral broadening effects are not properly described by theory, especially at pressure levels exceeding 20 bar, which culminates in a clear underestimation of the derived pressure data by SC absorption spectroscopy. Nevertheless, temperature can be determined accurately by performing a three-parameter fit based on water mole fraction, temperature, and pressure. In contrast, making use of pressure transducer data as look-up values and varying only temperature and H2O mole fraction to find the best match leads to a clear overestimation of temperature at elevated pressures. PMID:27409013

  19. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, G.W.; Bushman, J.F.; Alger, T.W.

    1996-07-23

    A vacuum housing and pumping system is described for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof. 7 figs.

  20. Mass spectrometer vacuum housing and pumping system

    DOEpatents

    Coutts, Gerald W.; Bushman, John F.; Alger, Terry W.

    1996-01-01

    A vacuum housing and pumping system for a portable gas chromatograph/mass spectrometer (GC/MS). The vacuum housing section of the system has minimum weight for portability while designed and constructed to utilize metal gasket sealed stainless steel to be compatible with high vacuum operation. The vacuum pumping section of the system consists of a sorption (getter) pump to remove atmospheric leakage and outgassing contaminants as well as the gas chromatograph carrier gas (hydrogen) and an ion pump to remove the argon from atmospheric leaks. The overall GC/MS system has broad application to contaminants, hazardous materials, illegal drugs, pollution monitoring, etc., as well as for use by chemical weapon treaty verification teams, due to the light weight and portability thereof.

  1. First Results from the Modular Total Absorption Spectrometer at the HRIBF

    SciTech Connect

    Fijałkowska, A.; Karny, M.; Rykaczewski, K.P.; Wolińska-Cichocka, M.; Grzywacz, R.; Gross, C.J.; Johnson, J.W.; Rasco, B.C.; Zganjar, E.F.; Stracener, D.W.; Jost, C.; Goetz, K.C.; Goans, R.; Spejewski, E.; Cartegni, L.; Madurga, M.; Miernik, K.; Miller, D.; Padgett, S.W.; Paulauskas, S.V.; and others

    2014-06-15

    A Modular Total Absorption Spectrometer constructed at the Holifield Radioactive Ion Beam Facility has been applied to decay studies of over 20 {sup 238}U fission products. The measurements were focused on nuclei identified as important for decay heat analysis during a nuclear fuel cycle. Preliminary results on the average electromagnetic (EM) energy release in the β decay of {sup 89}Kr and {sup 139}Xe isotopes yielded values of 2446 keV and 1126 keV, respectively. It represents an increase of over 35% and 20%, respectively, when compared to the average EM energies deduced using the ENSDF database.

  2. Measurement of fission products β decay properties using a total absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Zakari-Issoufou, A.-A.; Porta, A.; Fallot, M.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Agramunt, J.; Äystö, J.; Bowry, M.; Bui, V. M.; Caballero-Folch, R.; Cano-Ott, D.; Eloma, V.; Estévez, E.; Farrelly, G. F.; Garcia, A.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez, A.; Podolyak, Zs.; Penttilä, H.; Regan, P. H.; Rissanen, J.; Rubio, B.; Weber, C.

    2013-12-01

    In a nuclear reactor, the β decay of fission fragments is at the origin of decay heat and antineutrino flux. These quantities are not well known while they are very important for reactor safety and for our understanding of neutrino physics. One reason for the discrepancies observed in the estimation of the decay heat and antineutrinos flux coming from reactors could be linked with the Pandemonium effect. New measurements have been performed at the JYFL facility of Jyväskylä with a Total Absorption Spectrometer (TAS) in order to circumvent this effect. An overview of the TAS technique and first results from the 2009 measurement campaign will be presented.

  3. First Results from the Modular Total Absorption Spectrometer at the HRIBF

    NASA Astrophysics Data System (ADS)

    Fijałkowska, A.; Karny, M.; Rykaczewski, K. P.; Wolińska-Cichocka, M.; Grzywacz, R.; Gross, C. J.; Johnson, J. W.; Rasco, B. C.; Zganjar, E. F.; Stracener, D. W.; Jost, C.; Goetz, K. C.; Goans, R.; Spejewski, E.; Cartegni, L.; Madurga, M.; Miernik, K.; Miller, D.; Padgett, S. W.; Paulauskas, S. V.; Al-Shudifat, M.; Hamilton, J. H.; Ramayya, A. V.

    2014-06-01

    A Modular Total Absorption Spectrometer constructed at the Holifield Radioactive Ion Beam Facility has been applied to decay studies of over 20 238U fission products. The measurements were focused on nuclei identified as important for decay heat analysis during a nuclear fuel cycle. Preliminary results on the average electromagnetic (EM) energy release in the β decay of 89Kr and 139Xe isotopes yielded values of 2446 keV and 1126 keV, respectively. It represents an increase of over 35% and 20%, respectively, when compared to the average EM energies deduced using the ENSDF database.

  4. Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) Aircraft Measurements of CO2

    NASA Technical Reports Server (NTRS)

    Christensen, Lance E.; Spiers, Gary D.; Menzies, Robert T.; Jacob, Joseph C.; Hyon, Jason

    2011-01-01

    The Jet Propulsion Laboratory Carbon Dioxide Laser Absorption Spectrometer (CO2LAS) utilizes Integrated Path Differential Absorption (IPDA) at 2.05 microns to obtain CO2 column mixing ratios weighted heavily in the boundary layer. CO2LAS employs a coherent detection receiver and continuous-wave Th:Ho:YLF laser transmitters with output powers around 100 milliwatts. An offset frequency-locking scheme coupled to an absolute frequency reference enables the frequencies of the online and offline lasers to be held to within 200 kHz of desired values. We describe results from 2009 field campaigns when CO2LAS flew on the Twin Otter. We also describe spectroscopic studies aimed at uncovering potential biases in lidar CO2 retrievals at 2.05 microns.

  5. A broadband absorption spectrometer using light emitting diodes for ultrasensitive, in situ trace gas detection

    SciTech Connect

    Langridge, Justin M.; Shillings, Alexander J. L.; Jones, Roderic L.; Ball, Stephen M.

    2008-12-15

    A broadband absorption spectrometer has been developed for highly sensitive and target-selective in situ trace gas measurements. The instrument employs two distinct modes of operation: (i) broadband cavity enhanced absorption spectroscopy (BBCEAS) is used to quantify the concentration of gases in sample mixtures from their characteristic absorption features, and (ii) periodic measurements of the cavity mirrors' reflectivity are made using step-scan phase shift cavity ringdown spectroscopy (PSCRDS). The latter PSCRDS method provides a stand-alone alternative to the more usual method of determining mirror reflectivities by measuring BBCEAS absorption spectra for calibration samples of known composition. Moreover, the instrument's two modes of operation use light from the same light emitting diode transmitted through the cavity in the same optical alignment, hence minimizing the potential for systematic errors between mirror reflectivity determinations and concentration measurements. The ability of the instrument to quantify absorber concentrations is tested in instrument intercomparison exercises for NO{sub 2} (versus a laser broadband cavity ringdown spectrometer) and for H{sub 2}O (versus a commercial hygrometer). A method is also proposed for calculating effective absorption cross sections for fitting the differential structure in BBCEAS spectra due to strong, narrow absorption lines that are under-resolved and hence exhibit non-Beer-Lambert law behavior at the resolution of the BBCEAS measurements. This approach is tested on BBCEAS spectra of water vapor's 4v+{delta} absorption bands around 650 nm. The most immediate analytical application of the present instrument is in quantifying the concentration of reactive trace gases in the ambient atmosphere. The instrument's detection limits for NO{sub 3} as a function of integration time are considered in detail using an Allan variance analysis. Experiments under laboratory conditions produce a 1{sigma} detection limit

  6. Modeling the Performance of a Spaceborne Laser Absorption Spectrometer for Atmospheric CO2 Column Measurements

    NASA Astrophysics Data System (ADS)

    Lin, B.; Ismail, S.; Harrison, F. W.; Browell, E. V.; Nehrir, A. R.; Dobler, J. T.; Moore, B.; Refaat, T.; Kooi, S. A.

    2013-12-01

    Accurate global observations of atmospheric carbon dioxide (CO2) with a laser-based space mission, such as the NASA ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission, are crucial to improving our understanding of global CO2 sources and sinks. This study focuses on modeling of the performance of a spaceborne laser absorption spectrometer (LAS) system for CO2 column measurements. The model accounts for all of the fundamental physics of the instrument subsystems and components and the influences of measurement environments. The characteristics of simulated LAS systems and their components are based on existing technologies and the implementation of operational systems. The modeled instrument is specifically assumed to be an Intensity-Modulated Continuous-Wave (IM-CW) LAS system like the Exelis airborne Multifunctional Fiber Laser Lidar (MFLL) operating in the 1.57 um CO2 absorption band. Environmental effects such as gas absorption, solar radiation, scattering of aerosols and thin clouds, atmospheric turbulence, and surface reflection are also considered in the model. The modeled results are presented statistically from simulation ensembles of multiple model runs to accurately represent the random nature of all of the noise sources and uncertainties related to the LAS instruments and the measurement environments. Model simulations demonstrate very good agreement when compared to prior airborne and ground based MFLL measurements. The model predicted lidar return powers for various calibrated surface targets show good agreement with those measured by the MFLL instrument during ground tests at NASA Langley Research Center in the summer of 2012. The difference between modeled and measured signal-to-noise ratios (SNR) of the LAS CO2 column optical depths (Tau_d) for the summer 2011 flight campaign on board the NASA DC-8 over Railroad Valley (RRV), NV is generally within 20%. The simulations for spaceborne Tau_d measurements over RRV indicate

  7. Spectrometer system for optical reflectance measurements

    NASA Technical Reports Server (NTRS)

    Soller, Babs R. (Inventor); Phillipps, Patrick G. (Inventor); Parker, Michael S. (Inventor)

    2007-01-01

    A spectrometer system includes a thermal light source for illuminating a sample, where the thermal light source includes a filament that emits light when heated. The system additionally includes a spectrograph for measuring a light spectrum from the sample and an electrical circuit for supplying electrical current to the filament to heat the filament and for controlling a resistance of the filament. The electrical circuit includes a power supply that supplies current to the filament, first electrical components that sense a current through the filament, second electrical components that sense a voltage drop across the filament, third electrical components that compare a ratio of the sensed voltage drop and the sensed current with a predetermined value, and fourth electrical components that control the current through the filament or the voltage drop across the filament to cause the ratio to equal substantially the predetermined value.

  8. Multipass optical absorption spectroscopy: a fast-scanning laser spectrometer for the in situ determination of atmospheric trace-gas components, in particular OH.

    PubMed

    Armerding, W; Spiekermann, M; Walter, J; Comes, F J

    1996-07-20

    The optical design of an absorption spectrometer for in situ measurements of atmospheric trace gases is reported. The light source is a rapidly tuned and power-stabilized dye-ring laser, which is frequency doubled by an intracavity BBO crystal. The second harmonic and the fundamental are used simultaneously for measurement of OH, SO(2), CH(2)O, and naphthalene in the UV and of NO(2) in the visible. The 1.2-km absorption path is folded within a 6-m White-cell-type multiple-reflection system with an open-path setup. The absorption sensitivity of the spectrometer is better than 1 part in 10(-5) under tropospheric conditions (integration time 1 min., signal-to-noise ratio 1). PMID:21102830

  9. The RPC System for the Opera Spectrometers

    NASA Astrophysics Data System (ADS)

    Dusini, S.

    2006-04-01

    OPERA is one of the two detectors foreseen in the CNGS (CERN Neutrino to Gran Sasso) project, devoted to the detection of νμ ↔ ντ oscillations in the parameter region suggested by SuperKamiokande. The tracking system inside the iron yoke of the muon spectrometer makes use of Resistive Plate Chambers (RPC) with bakelite electrodes in a large scale application. We present here full design of the project. Four RPC planes were instrumented and the first tests were performed confirming a good behavior of the installed RPCs in terms of intrinsic noise and operating currents and efficiency. In the paper we present also some results on RPC aging studies.

  10. Spectrometer system for diffuse extreme ultraviolet radiation

    NASA Technical Reports Server (NTRS)

    Labov, Simon E.

    1989-01-01

    A unique grazing incidence spectrometer system has been designed to study diffuse line emission between 80 and 650 A with 10-30 A resolution. The minimum detectable emission line strength during a 5-min observation ranges from 100-2000 ph/sq cm sec str. The instrument uses mechanically ruled reflection gratings placed in front of a linear array of mirrors. These mirrors focus the spectral image on microchannel plate detectors located behind thin filters. The field of view is 40 min of arc by 15 deg, and there is no spatial imaging. This instrument has been fabricated, calibrated, and successfully flown on a sounding rocket to observe the astronomical background radiation.

  11. High energy resolution five-crystal spectrometer for high quality fluorescence and absorption measurements on an x-ray absorption spectroscopy beamline

    SciTech Connect

    Llorens, Isabelle; Lahera, Eric; Delnet, William; Proux, Olivier; Dermigny, Quentin; Gelebart, Frederic; Morand, Marc; Shukla, Abhay; Bardou, Nathalie; Ulrich, Olivier; and others

    2012-06-15

    Fluorescence detection is classically achieved with a solid state detector (SSD) on x-ray absorption spectroscopy (XAS) beamlines. This kind of detection however presents some limitations related to the limited energy resolution and saturation. Crystal analyzer spectrometers (CAS) based on a Johann-type geometry have been developed to overcome these limitations. We have tested and installed such a system on the BM30B/CRG-FAME XAS beamline at the ESRF dedicated to the structural investigation of very dilute systems in environmental, material and biological sciences. The spectrometer has been designed to be a mobile device for easy integration in multi-purpose hard x-ray synchrotron beamlines or even with a laboratory x-ray source. The CAS allows to collect x-ray photons from a large solid angle with five spherically bent crystals. It will cover a large energy range allowing to probe fluorescence lines characteristic of all the elements from Ca (Z = 20) to U (Z = 92). It provides an energy resolution of 1-2 eV. XAS spectroscopy is the main application of this device even if other spectroscopic techniques (RIXS, XES, XRS, etc.) can be also achieved with it. The performances of the CAS are illustrated by two experiments that are difficult or impossible to perform with SSD and the complementarity of the CAS vs SSD detectors is discussed.

  12. Evaluation of Small Mass Spectrometer Systems

    NASA Technical Reports Server (NTRS)

    Arkin, C. Richard; Griffin, Timothy P.; Ottens, Andrew K.; Diaz, Jorge A.; Follistein, Duke W.; Adams, Fredrick W.; Helms, William R.; Voska, N. (Technical Monitor)

    2002-01-01

    This work is aimed at understanding the aspects of designing a miniature mass spectrometer (MS) system. A multitude of commercial and government sectors, such as the military, environmental agencies and industrial manufacturers of semiconductors, refrigerants, and petroleum products, would find a small, portable, rugged and reliable MS system beneficial. Several types of small MS systems are evaluated and discussed, including linear quadrupole, quadrupole ion trap, time of flight and sector. The performance of each system in terms of accuracy, precision, limits of detection, response time, recovery time, scan rate, volume and weight is assessed. A performance scale is setup to rank each systems and an overall performance score is given to each system. All experiments involved the analysis of hydrogen, helium, oxygen and argon in a nitrogen background with the concentrations of the components of interest ranging from 0-5000 part-per-million (ppm). The relative accuracies of the systems vary from < 1% to approx. 40% with an average below 10%. Relative precisions varied from 1% to 20%, with an average below 5%. The detection limits had a large distribution, ranging from 0.2 to 170 ppm. The systems had a diverse response time ranging from 4 s to 210 s as did the recovery time with a 6 s to 210 s distribution. Most instruments had scan times near, 1 s, however one instrument exceeded 13 s. System weights varied from 9 to 52 kg and sizes from 15 x 10(exp 3)cu cm to 110 x 10(exp 3) cu cm.

  13. A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

    NASA Technical Reports Server (NTRS)

    Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

    2010-01-01

    We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

  14. Difference-Frequency-Based Tunable Absorption Spectrometer for Detection of Atmospheric Formaldehyde

    NASA Astrophysics Data System (ADS)

    Lancaster, David G.; Fried, Alan; Wert, Bryan; Henry, Bruce; Tittel, Frank K.

    2000-08-01

    High-sensitivity detection of formaldehyde (CH 2 O) at 3.5315 m (2831.64 cm 1 ) is reported with a diode-laser-pumped, fiber-coupled, periodically poled LiNbO 3 spectroscopic source. This source replaced the Pb salt diode laser Dewar assembly of an existing tunable diode-laser absorption spectrometer designed for ultrasensitive detection of CH 2 O. Spectra are recorded with 2 f -modulation spectroscopy and zero-air rapid background subtraction. Initial measurements reported here, determined from multiple measurements of a flowing 7.7 parts per billion by volume (ppbv, parts in 10 9 ) CH 2 O in air mixture, indicate replicate precisions as low as 0.24 ppbv.

  15. Difference-frequency-based tunable absorption spectrometer for detection of atmospheric formaldehyde

    NASA Technical Reports Server (NTRS)

    Lancaster, D. G.; Fried, A.; Wert, B.; Henry, B.; Tittel, F. K.

    2000-01-01

    High-sensitivity detection of formaldehyde (CH2O) at 3.5315 micrometers (2831.64 cm-1) is reported with a diode-laser-pumped, fiber-coupled, periodically poled LiNbO3 spectroscopic source. This source replaced the Pb-salt diode laser Dewar assembly of an existing tunable diode-laser absorption spectrometer designed for ultrasensitive detection of CH2O. Spectra are recorded with 2f-modulation spectroscopy and zero-air rapid background subtraction. Initial measurements reported here, determined from multiple measurements of a flowing 7.7 parts per billion by volume (ppbv, parts in 10(9)) CH2O in air mixture, indicate replicate precisions as low as 0.24 ppbv.

  16. Results of fission products β decay properties measurement performed with a total absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Zakari-Issoufou, A.-A.; Porta, A.; Fallot, M.; Algora, A.; Tain, J. L.; Valencia, E.; Rice, S.; Agramunt, J.; Äystö, J.; Bowry, M.; Bui, V. M.; Caballero-Folch, R.; Cano-Ott, D.; Eloma, V.; Estévez, E.; Farrelly, G. F.; Garcia, A.; Gelletly, W.; Gomez-Hornillos, M. B.; Gorlychev, V.; Hakala, J.; Jokinen, A.; Jordan, M. D.; Kankainen, A.; Kondev, F. G.; Martinez, T.; Mendoza, E.; Molina, F.; Moore, I.; Perez, A.; Podolyak, Zs.; Penttilä, H.; Regan, P. H.; Rissanen, J.; Rubio, B.; Weber, C.

    2014-03-01

    β-decay properties of fission products are very important for applied reactor physics, for instance to estimate the decay heat released immediately after the reactor shutdown and to estimate the bar ν flux emitted. An accurate estimation of the decay heat and the bar ν emitted flux from reactors, are necessary for purposes such as reactors operation safety and non-proliferation. In order to improve the precision in the prediction for these quantities, the bias due to the Pandemonium effect affecting some important fission product data has to be corrected. New measurements of fission products β-decay, not sensitive to this effect, have been performed with a Total Absorption Spectrometer (TAS) at the JYFL facility of Jyväskylä. An overview of the TAS technique and first results from the 2009 campaign will be presented.

  17. Application of independent component analysis method in real-time spectral analysis of gaseous mixtures for acousto-optical spectrometers based on differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Fadeyev, A. V.; Pozhar, V. E.

    2012-10-01

    It is discussed the reliability problem of time-optimized method for remote optical spectral analysis of gas-polluted ambient air. The method based on differential optical absorption spectroscopy (DOAS) enables fragmentary spectrum registration (FSR) and is suitable for random-spectral-access (RSA) optical spectrometers like acousto-optical (AO) ones. Here, it is proposed the algorithm based on statistical method of independent component analysis (ICA) for estimation of a correctness of absorption spectral lines selection for FSR-method. Implementations of ICA method for RSA-based real-time adaptive systems are considered. Numerical simulations are presented with use of real spectra detected by the trace gas monitoring system GAOS based on AO spectrometer.

  18. NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR OPERATION, CALIBRATION AND MAINTENANCE OF THE PERKIN-ELMER ZEEMAN/5000 SYSTEM ATOMIC ABSORPTION SPECTROMETER (BCO-L-6.0)

    EPA Science Inventory

    The purpose of this SOP is to outline the start-up, calibration, operation, and maintenance procedures for the Perkin-Elmer 5000 atomic absorption spectrophotometer (PE 5000 AA), and the Perkin Elmer 5000 Zeeman graphite furnace atomic absorption spectrophotometer (PE 5000Z GFAA)...

  19. Backscatter absorption gas imaging system

    DOEpatents

    McRae, Jr., Thomas G.

    1985-01-01

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  20. Backscatter absorption gas imaging system

    DOEpatents

    McRae, T.G. Jr.

    A video imaging system for detecting hazardous gas leaks. Visual displays of invisible gas clouds are produced by radiation augmentation of the field of view of an imaging device by radiation corresponding to an absorption line of the gas to be detected. The field of view of an imager is irradiated by a laser. The imager receives both backscattered laser light and background radiation. When a detectable gas is present, the backscattered laser light is highly attenuated, producing a region of contrast or shadow on the image. A flying spot imaging system is utilized to synchronously irradiate and scan the area to lower laser power requirements. The imager signal is processed to produce a video display.

  1. Multispectral imaging of tissue absorption and scattering using spatial frequency domain imaging and a computed-tomography imaging spectrometer

    PubMed Central

    Weber, Jessie R.; Cuccia, David J.; Johnson, William R.; Bearman, Gregory H.; Durkin, Anthony J.; Hsu, Mike; Lin, Alexander; Binder, Devin K.; Wilson, Dan; Tromberg, Bruce J.

    2011-01-01

    We present an approach for rapidly and quantitatively mapping tissue absorption and scattering spectra in a wide-field, noncontact imaging geometry by combining multifrequency spatial frequency domain imaging (SFDI) with a computed-tomography imaging spectrometer (CTIS). SFDI overcomes the need to spatially scan a source, and is based on the projection and analysis of periodic structured illumination patterns. CTIS provides a throughput advantage by simultaneously diffracting multiple spectral images onto a single CCD chip to gather spectra at every pixel of the image, thus providing spatial and spectral information in a single snapshot. The spatial-spectral data set was acquired 30 times faster than with our wavelength-scanning liquid crystal tunable filter camera, even though it is not yet optimized for speed. Here we demonstrate that the combined SFDI-CTIS is capable of rapid, multispectral imaging of tissue absorption and scattering in a noncontact, nonscanning platform. The combined system was validated for 36 wavelengths between 650–1000 nm in tissue simulating phantoms over a range of tissue-like absorption and scattering properties. The average percent error for the range of absorption coefficients (μa) was less than 10% from 650–800 nm, and less than 20% from 800–1000 nm. The average percent error in reduced scattering coefficients (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}\\mu_{\\rm s}^{\\prime}\\end{equation*} \\end{document}μs′) was less than 5% from 650–700 nm and less than 3% from 700–1000 nm. The SFDI-CTIS platform was applied to a mouse model of brain injury in order to demonstrate the utility of this approach in characterizing spatially and spectrally varying tissue optical properties. PMID:21280902

  2. Double conical crystal x-ray spectrometer for high resolution ultrafast x-ray absorption near-edge spectroscopy of Al K edge

    NASA Astrophysics Data System (ADS)

    Levy, A.; Dorchies, F.; Fourment, C.; Harmand, M.; Hulin, S.; Santos, J. J.; Descamps, D.; Petit, S.; Bouillaud, R.

    2010-06-01

    An x-ray spectrometer devoted to dynamical studies of transient systems using the x-ray absorption fine spectroscopy technique is presented in this article. Using an ultrafast laser-induced x-ray source, this optical device based on a set of two potassium acid phthalate conical crystals allows the extraction of x-ray absorption near-edge spectroscopy structures following the Al absorption K edge. The proposed experimental protocol leads to a measurement of the absorption spectra free from any crystal reflectivity defaults and shot-to-shot x-ray spectral fluctuation. According to the detailed analysis of the experimental results, a spectral resolution of 0.7 eV rms and relative fluctuation lower than 1% rms are achieved, demonstrated to be limited by the statistics of photon counting on the x-ray detector.

  3. Simulations of an airborne laser absorption spectrometer for atmospheric CO2 measurements

    NASA Astrophysics Data System (ADS)

    Lin, B.; Ismail, S.; Harrison, F. W.; Browell, E. V.; Dobler, J. T.; Refaat, T.; Kooi, S. A.

    2012-12-01

    Atmospheric column amount of carbon dioxide (CO2), a major greenhouse gas of the atmosphere, has significantly increased from a preindustrial value of about 280 parts per million (ppm) to more than 390 ppm at present. Our knowledge about the spatiotemporal change and variability of the greenhouse gas, however, is limited. Thus, a near-term space mission of the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) is crucial to increase our understanding of global sources and sinks of CO2. Currently, NASA Langley Research Center (LaRC) and ITT Exelis are jointly developing and testing an airborne laser absorption spectrometer (LAS) as a prototype instrument for the mission. To assess the space capability of accurate atmospheric CO2 measurements, accurate modeling of the instrument and practical evaluation of space applications are the keys for the success of the ASCENDS mission. This study discusses the simulations of the performance of the airborne instrument and its CO2 measurements. The LAS is a multi-wavelength spectrometer operating on a 1.57 um CO2 absorption line. The Intensity-Modulated Continuous-Wave (IM-CW) approach is implemented in the instrument. To reach accurate CO2 measurements, transmitted signals are monitored internally as reference channels. A model of this kind of instrument includes all major components of the spectrometer, such as modulation generator, fiber amplifier, telescope, detector, transimpedance amplifier, matched filter, and other signal processors. The characteristics of these components are based on actual laboratory tests, product specifications, and general understanding of the functionality of the components. For simulations of atmospheric CO2 measurements, environmental conditions related to surface reflection, atmospheric CO2 and H2O profiles, thin clouds, and aerosol layers, are introduced into the model. Furthermore, all major noise sources such as those from detectors, background radiation, speckle, and

  4. Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center

    DOE Data Explorer

    Greenwood, R. E.

    A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

  5. A doubly curved elliptical crystal spectrometer for the study of localized x-ray absorption in hot plasmas

    NASA Astrophysics Data System (ADS)

    Cahill, Adam D.; Hoyt, Cad L.; Pikuz, Sergei A.; Shelkovenko, Tania; Hammer, David A.

    2014-10-01

    X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emitted by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here the foundational work in the design and development of this spectrometer along with initial results obtained with an aluminum x-pinch as the object plasma.

  6. A doubly curved elliptical crystal spectrometer for the study of localized x-ray absorption in hot plasmas

    SciTech Connect

    Cahill, Adam D. Hoyt, Cad L.; Pikuz, Sergei A.; Shelkovenko, Tania; Hammer, David A.

    2014-10-15

    X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emitted by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here the foundational work in the design and development of this spectrometer along with initial results obtained with an aluminum x-pinch as the object plasma.

  7. A High Precision Scanning Control System For A VUV Fourier Transform Spectrometer

    SciTech Connect

    De Oliveira, N.; Nahon, L.; Polack, F.; Joyeux, D.; Phalippou, D.; Rodier, J. C.; Vervloeet, M.

    2007-01-19

    A VUV Fourier transform spectrometer based on a wavefront division interferometer has been built. Our ultimate goal is to provide a high resolution absorption spectrometer in the 140 - 40 nm range using the new third generation French synchrotron source Soleil as the background continuum. Here, we present the design and latest performance of the instrument scanning control system. It is based on multiple reflections of a monomode, frequency-stabilized HeNe laser between two plane mirrors allowing the required sensitivity on the displacement of the interferometer mobile arm. The experimental results on the sampling precision show an rms error below 5 nm for a travel length of 7.5 mm.

  8. ATLAS: Airborne Tunable Laser Absorption Spectrometer for stratospheric trace gas measurements

    NASA Technical Reports Server (NTRS)

    Loewenstein, Max; Podolske, James R.; Strahan, Susan E.

    1990-01-01

    The ATLAS instrument is an advanced technology diode laser based absorption spectrometer designed specifically for stratospheric tracer studies. This technique was used in the acquisition of N2O tracer data sets on the Airborne Antarctic Ozone Experiment and the Airborne Arctic Stratospheric Expedition. These data sets have proved valuable for comparison with atmospheric models, as well as in assisting in the interpretation of the entire ensemble of chemical and meteorological data acquired on these two field studies. The N2O dynamical tracer data set analysis revealed several ramifications concerning the polar atmosphere: the N2O/NO(y) correlation, which is used as a tool to study denitrification in the polar vertex; the N2O Southern Hemisphere morphology, showing subsidence in the winter polar vortex; and the value of the N2O measurements in the interpretation of ClO, O3, and NO(y) measurements and of the derived dynamical tracer, potential vorticity. Field studies also led to improved characterization of the instrument and to improved accuracy.

  9. Measurement of the Spectral Absorption of Liquid Water in Melting Snow With an Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Dozier, Jeff

    1995-01-01

    Melting of the snowpack is a critical parameter that drives aspects of the hydrology in regions of the Earth where snow accumulates seasonally. New techniques for measurement of snow melt over regional scales offer the potential to improve monitoring and modeling of snow-driven hydrological processes. In this paper we present the results of measuring the spectral absorption of liquid water in a melting snowpack with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). AVIRIS data were acquired over Mammoth Mountain, in east central California on 21 May 1994 at 18:35 UTC. The air temperature at 2926 m on Mammoth Mountain at site A was measured at 15-minute intervals during the day preceding the AVIRIS data acquisition. At this elevation. the air temperature did not drop below freezing the night of the May 20 and had risen to 6 degrees Celsius by the time of the overflight on May 21. These temperature conditions support the presence of melting snow at the surface as the AVIRIS data were acquired.

  10. Measurement of the spectral absorption of liquid water in melting snow with an imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Dozier, Jeff

    1995-01-01

    Melting of the snowpack is a critical parameter that drives aspects of the hydrology in regions of the earth where snow accumulates seasonally. New techniques for measurement of snow melt over regional scales offer the potential to improve monitoring and modeling of snow-driven hydrological processes. We present the results of measuring the spectral absorption of liquid water in a melting snowpack with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). AVIRIS data were acquired over Mammoth Mountain, in east central California on 21 May 1994 at 18:35 UTC. The air temperature at 2926 m on Mammoth Mountain at site A was measured at 15-minute intervals during the day preceding the AVIRIS data acquisition. At this elevation, the air temperature did not drop below freezing the night of May 20 and had risen to 6 degrees Celsius by the time of the overflight on May 21. These temperature conditions support the presence of melting snow at the surface as the AVIRIS data were acquired.

  11. First experiment with the NUSTAR/FAIR Decay Total Absorption γ -Ray Spectrometer (DTAS) at the IGISOL IV facility

    NASA Astrophysics Data System (ADS)

    Guadilla, V.; Algora, A.; Tain, J. L.; Agramunt, J.; Äystö, J.; Briz, J. A.; Cano-Ott, D.; Cucoanes, A.; Eronen, T.; Estienne, M.; Fallot, M.; Fraile, L. M.; Ganioglu, E.; Gelletly, W.; Gorelov, D.; Hakala, J.; Jokinen, A.; Jordan, D.; Kankainen, A.; Kolhinen, V.; Koponen, J.; Lebois, M.; Martinez, T.; Monserrate, M.; Montaner-Pizá, A.; Moore, I.; Nácher, E.; Orrigo, S.; Penttilä, H.; Podolyak, Zs.; Pohjalainen, I.; Porta, A.; Regan, P.; Reinikainen, J.; Reponen, M.; Rinta-Antila, S.; Rubio, B.; Rytkönen, K.; Shiba, T.; Sonnenschein, V.; Sonzogni, A. A.; Valencia, E.; Vedia, V.; Voss, A.; Wilson, J. N.; Zakari-Issoufou, A.-A.

    2016-06-01

    The new Decay Total Absorption Spectrometer (DTAS) has been commissioned with low energy radioactive beams at the upgraded IGISOL IV facility. The DTAS is a segmented detector composed of up to 18 NaI(Tl) crystals and it will be a key instrument in the DESPEC experiment at FAIR. In this document we report on the experimental setup and the first measurements performed with DTAS at IGISOL. The detector was characterized by means of MC simulations, and this allowed us to calculate the response function of the spectrometer and analyse the first cases of interest.

  12. Development of a Transient Absorption Spectrometer for the Study of the Proton-motive Force (PMF) in Plant Thylakoid Membranes

    NASA Astrophysics Data System (ADS)

    Gardner, Jens Christopher

    A transient-absorption spectrometer to study the electric field component of the proton-motive force (PMF) has been developed. Excitation by an actinic light source (655nm) causes absorption changes of pigments in the sample at 520nm on the order of 0.1%. Using a probe light source at 520nm, the change in transmission before and after actinic excitation can be detected and quantified. Because the change in transmission is small, a high signal to noise ratio (SNR) is required. To reduce the effect of optical shot noise and front end electrical noise a high intensity source at 520nm is utilized. However, continuous high intensity light at 520nm over time can cause actinic excitation in the sample, so the 520nm probe is pulsed at high optical intensity and low duty cycle to reduce the net incident flux. The developed system includes 1) a LED driver to drive 1A current pulses through three high power probe LEDs and four high power actinic LEDs, 2) an analog front end which uses a 10mm by 10mm photodiode and a trans-impedance amplifier to detect the pulses, as well as several signal processing stages, 3) a microcontroller to generate the probe timing waveforms, digitize the detected signal, and send the data to a PC, and 4) a LabView computer interface to set input parameters, display the collected data, and save the data to a text file. Experimental verification of system peformance was performed by testing the system with and without a plant sample. The results show that the system works as expected and is capable of measuring the data required to determine the electric field component of the PMF.

  13. Fiber laser FBG sensor system by using a spectrometer demodulation

    NASA Astrophysics Data System (ADS)

    Kim, Hyunjin; Song, Minho

    2011-05-01

    We suggest a spectrometer demodulation method of FBG sensors for the possible uses in wind power generator's blade monitoring. High signal-to-noise ratio outputs and linear demodulation were obtained by combining a fiber laser light source and a spectrometer which used a holographic volume grating and a 512-pixel PD array. Preliminary experimental results are presented to show the feasibility of the suggested FBG demodulation system.

  14. A capillary absorption spectrometer for stable carbon isotope ratio (13C/12C) analysis in very small samples

    NASA Astrophysics Data System (ADS)

    Kelly, J. F.; Sams, R. L.; Blake, T. A.; Newburn, M.; Moran, J.; Alexander, M. L.; Kreuzer, H.

    2012-02-01

    A capillary absorption spectrometer (CAS) suitable for IR laser isotope analysis of small CO2 samples is presented. The system employs a continuous-wave (cw) quantum cascade laser to study nearly adjacent rovibrational transitions of different isotopologues of CO2 near 2307 cm-1 (4.34 μm). This initial CAS system can achieve relative isotopic precision of about 10 ppm 13C, or ˜1‰ (per mil in delta notation relative to Vienna Pee Dee Belemnite) with 20-100 picomoles of entrained sample within the hollow waveguide for CO2 concentrations ˜400-750 ppm. Isotopic analyses of such gas fills in a 1-mm ID hollow waveguide of 0.8 m overall physical path length can be carried out down to ˜2 Torr. Overall 13C/12C ratios can be calibrated to ˜2‰ accuracy with diluted CO2 standards. A novel, low-cost method to reduce cw-fringing noise resulting from multipath distortions in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level (peak-to-rms) after 1000 scans are co-added in ˜10 s. The CAS is meant to work directly with converted CO2 samples from a laser ablation-catalytic combustion micro-sampler to provide 13C/12C ratios of small biological isolates currently operating with spatial resolutions ˜50 μm.

  15. Intensity-Modulated Continuous-Wave Laser Absorption Spectrometer at 1.57 Micrometer for Atmospheric CO2 Measurements

    NASA Technical Reports Server (NTRS)

    Lin, Bing

    2014-01-01

    Understanding the earth's carbon cycle is essential for diagnosing current and predicting future climates, which requires precise global measurements of atmospheric CO2 through space missions. The Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) space mission will provide accurate global atmospheric CO2 measurements to meet carbon science requirements. The joint team of NASA Langley Research Center and ITT Exelis, Inc. proposes to use the intensity-modulated, continuous-wave (IM-CW) laser absorption spectrometer (LAS) approach for the ASCENDS mission. Prototype LAS instruments have been developed and used to demonstrate the power, signal-to-noise ratio, precision and accuracy, spectral purity, and stability of the measurement and the instrument needed for atmospheric CO2 observations from space. The ranging capability from laser platform to ground surfaces or intermediate backscatter layers is achieved by transmitted range-encoded IM laser signals. Based on the prototype instruments and current lidar technologies, space LAS systems and their CO2 column measurements are analyzed. These studies exhibit a great potential of using IM-CW LAS system for the active space CO2 mission ASCENDS.

  16. Mapping of methane from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY)

    NASA Astrophysics Data System (ADS)

    Tan, K. C.; Lim, H. S.; MatJafri, M. Z.

    2012-11-01

    Among all the greenhouse gases, methane is the most dynamic and abundant greenhouse gas in the atmosphere. The global concentrations of atmospheric methane has increased more than doubled since pre-industrial times, with a current globally-averaged mixing ratio of ~ 1750 ppbv. Due to its high growth rate, methane brings significant effects on climate and atmospheric chemistry. There has a significant gap for variables between anthropogenic and natural sources and sinks of methane. Satellite observation of methane has been identified that it can provide the precise and accurate data globally, which sensitive to the small regional biases. We present measurements from Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) included on the European environmental satellite ENVISAT, launched on 1st of March 2002. Main objective of this study is to examine the methane distribution over Peninsular Malaysia using SCIAMACHY level-3 data. They are derived from the near-infrared nadir observations of the SCIAMACHY at the University of Bremen through scientific WFM-DOAS retrieval algorithm version 2.0.2.Maps of time averaged (yearly, tri-monthly) methane was generated and analyzed over Peninsular Malaysia for the year 2003 using PCI Geomatica 10.3 image processing software. The maps show dry-air column averaged mixing ratios of methane (denoted XCH4). It was retrieved using the interpolation technique. The concentration changes within boundary layer at all altitude levels are equally sensitive through the SCIAMACHY near-infrared nadir observations. Hence, we can make observation of methane at surface source region. The results successfully identify the area with highest and lowest concentration of methane at Peninsular Malaysia using SCIAMACHY data. Therefore, the study is suitable to examine the distribution of methane at tropical region.

  17. Eddy covariance carbonyl sulfide flux measurements with a quantum cascade laser absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Gerdel, Katharina; Spielmann, Felix M.; Hammerle, Albin; Wohlfahrt, Georg

    2016-04-01

    Carbonyl sulfide (COS) is the most abundant sulfur containing trace gas present in the troposphere at concentrations of around 500 ppt. Recent interest in COS by the ecosystem-physiological community has been sparked by the fact that COS co-diffuses into plant leaves pretty much the same way as carbon dioxide (CO2) does, but in contrast to CO2, COS is not known to be emitted by plants. Thus uptake of COS by vegetation has the potential to be used as a tracer for canopy gross photosynthesis, which cannot be measured directly, however represents a key term in the global carbon cycle. Since a few years, quantum cascade laser absorption spectrometers (QCLAS) are commercially available with the precision, sensitivity and time response suitable for eddy covariance (EC) flux measurements. While there exist a handful of published reports on EC flux measurements in the recent literature, no rigorous investigation of the applicability of QCLAS for EC COS flux measurements has been carried out so far, nor have been EC processing and QA/QC steps developed for carbon dioxide and water vapor flux measurements within FLUXNET been assessed for COS. The aim of this study is to close this knowledge gap, to discuss critical steps in the post-processing chain of COS EC flux measurements and to devise best-practice guidelines for COS EC flux data processing. To this end we collected EC COS (and CO2, H2O and CO) flux measurements above a temperate mountain grassland in Austria over the vegetation period 2015 with a commercially available QCLAS. We discuss various aspects of EC data post-processing, in particular issues with the time-lag estimation between sonic anemometer and QCLAS signals and QCLAS time series detrending, as well as QA/QC, in particular flux detection limits, random flux uncertainty, the interaction of various processing steps with common EC QA/QC filters (e.g. detrending and stationarity tests), u*-filtering, etc.

  18. Data acquisition and instrument control system for neutron spectrometers

    NASA Astrophysics Data System (ADS)

    Naik, S. S.; Kotwal, Ismat; Chandak, R. M.; Gaonkar, V. G.

    2004-08-01

    A personal computer (PC)-based data acquisition and instrument control system has been developed for neutron spectrometers in Dhruva reactor hall and Guide Tube laboratory. Efforts have been made to make the system versatile so that it can be used for controlling various neutron spectrometers using single end-on detector in step scan mode. Commercially available PC add-on cards have been used for input--output and timer-counter operations. An interface card and DC motor driver card have been developed indigenously. Software for the system has been written in Visual C++ language using MS Windows operating system. This data acquisition and instrument control system is successfully controlling four spectrometers at Dhruva reactor.

  19. Extended Evaluations of the Commercial Spectrometer Systems for Safeguards Applications

    SciTech Connect

    Duc T. Vo

    1999-08-01

    Safeguards applications require the best of the spectrometer system with excellent resolution, stability, and throughput. Instruments must perform well in all situations and environments. Data communication to the computer should be convenient, fast, and reliable. The software should have all the necessary tools and be easy to use. Portable systems should be small in size, lightweight, and have a long battery life. Nine commercially available spectrometer systems are tested with five different germanium detectors. Considering the performance of the Digital Signal Processors (DSP), digital-based spectroscope y may become the way of future gamma-ray spectroscopy.

  20. Ion mobility spectrometer, spectrometer analyte detection and identification verification system, and method

    DOEpatents

    Atkinson, David A.

    2002-01-01

    Methods and apparatus for ion mobility spectrometry and analyte detection and identification verification system are disclosed. The apparatus is configured to be used in an ion mobility spectrometer and includes a plurality of reactant reservoirs configured to contain a plurality of reactants which can be reacted with the sample to form adducts having varying ion mobilities. A carrier fluid, such as air or nitrogen, is used to carry the sample into the spectrometer. The plurality of reactants are configured to be selectively added to the carrier stream by use inlet and outlet manifolds in communication with the reagent reservoirs, the reservoirs being selectively isolatable by valves. The invention further includes a spectrometer having the reagent system described. In the method, a first reactant is used with the sample. Following a positive result, a second reactant is used to determine whether a predicted response occurs. The occurrence of the second predicted response tends to verify the existence of a component of interest within the sample. A third reactant can also be used to provide further verification of the existence of a component of interest. A library can be established of known responses of compounds of interest with various reactants and the results of a specific multi-reactant survey of a sample can be compared against the library to determine whether a component detected in the sample is likely to be a specific component of interest.

  1. Airborne Measurements of Formaldehyde Employing a Tunable Diode Laser Absorption Spectrometer During TRACE-P

    NASA Technical Reports Server (NTRS)

    Fried, Alan; Drummond, James

    2003-01-01

    This final report summarizes the progress achieved over the entire 3-year proposal period including two extensions spanning 1 year. These activities include: 1) Preparation for and participation in the NASA 2001 TRACE-P campaign using our airborne tunable diode laser system to acquire measurements of formaldehyde (CH2O); 2) Comprehensive data analysis and data submittal to the NASA archive; 3) Follow up data interpretation working with NASA modelers to place our ambient CH2O measurements into a broader photochemical context; 4) Publication of numerous JGR papers using this data; 5) Extensive follow up laboratory tests on the selectivity and efficiency of our CH20 scrubbing system; and 6) An extensive follow up effort to assess and study the mechanical stability of our entire optical system, particularly the multipass absorption cell, with aircraft changes in cabin pressure.

  2. Ray tracing package through a lens system and a spectrometer

    SciTech Connect

    Zurro, B.; King, P.W.; Lazarus, E.A.

    1980-03-01

    To study the light collection optics of the ISX-B two-dimensional (2-D) Thomson scattering system, we have implemented in the Oak Ridge National Laboratory (ORNL) Fusion Energy Division (FED) PDP-10 two computer programs, LENS and SPECT, that trace rays through a lens system and a spectrometer, respectively. The lens package follows the path of any kind of ray (meridional or skew) through a centered optical system formed by an arbitrary number of spherical surfaces. The spectrometer package performs geometrical ray tracing through a Czerney-Turner spectrometer and can be easily modified for studying any other configuration. Contained herein is a description of the procedures followed and a listing of the computer programs.

  3. Laser Absorption spectrometer instrument for tomographic 2D-measurement of climate gas emission from soils

    NASA Astrophysics Data System (ADS)

    Seidel, Anne; Wagner, Steven; Dreizler, Andreas; Ebert, Volker

    2014-05-01

    One of the most intricate effects in climate modelling is the role of permafrost thawing during the global warming process. Soil that has formerly never totally lost its ice cover now emits climate gases due to melting processes[1]. For a better prediction of climate development and possible feedback mechanisms, insights into physical procedures (like e.g. gas emission from underground reservoirs) are required[2]. Therefore, a long-term quantification of greenhouse gas concentrations (and further on fluxes) is necessary and the related structures that are responsible for emission need to be identified. In particular the spatial heterogeneity of soils caused by soil internal structures (e.g. soil composition changes or surface cracks) or by surface modifications (e.g. by plant growth) generate considerable complexities and difficulties for local measurements, for example with soil chambers. For such situations, which often cannot be avoided, a spatially resolved 2D-measurement to identify and quantify the gas emission from the structured soil would be needed, to better understand the influence of the soil sub-structures on the emission behavior. Thus we designed a spatially scanning laser absorption spectrometer setup to determine a 2D-gas concentration map in the soil-air boundary layer. The setup is designed to cover the surfaces in the range of square meters in a horizontal plane above the soil to be investigated. Existing field instruments for gas concentration or flux measurements are based on point-wise measurements, so structure identification is very tedious or even impossible. For this reason, we have developed a tomographic in-situ instrument based on TDLAS ('tunable diode laser absorption spectroscopy') that delivers absolute gas concentration distributions of areas with 0.8m × 0.8m size, without any need for reference measurements with a calibration gas. It is a simple and robust device based on a combination of scanning mirrors and reflecting foils, so

  4. Advanced integrated spectrometer designs for miniaturized optical coherence tomography systems

    NASA Astrophysics Data System (ADS)

    Akca, B. I.; Považay, B.; Chang, L.; Alex, A.; Wörhoff, K.; de Ridder, R. M.; Drexler, W.; Pollnau, M.

    2013-06-01

    Optical coherence tomography (OCT) has enabled clinical applications that revolutionized in vivo medical diagnostics. Nevertheless, its current limitations owing to cost, size, complexity, and the need for accurate alignment must be overcome by radically novel approaches. Exploiting integrated optics, the central components of a spectral-domain OCT (SD-OCT) system can be integrated on a chip. Arrayed-waveguide grating (AWG) spectrometers with their high spectral resolution and compactness are excellent candidates for on-chip SD-OCT systems. However, specific design-related issues of AWG spectrometers limit the performance of on-chip SD-OCT systems. Here we present advanced AWG designs which could overcome the limitations arising from free spectral range, polarization dependency, and curved focal plane of the AWG spectrometers. Using these advanced AWG designs in an SD-OCT system can provide not only better overall performance but also some unique aspects that a commercial system does not have. Additionally, a partially integrated OCT system comprising an AWG spectrometer and an integrated beam splitter, as well as the in vivo imaging using this system are demonstrated.

  5. Development Of A Supercontinuum Based Photoacoustic Aerosol Light Absorption And Albedo Spectrometer (PALAAS)

    NASA Astrophysics Data System (ADS)

    Arnold, Ian J.

    Aerosols are a major contributor to the global radiation budget because they modify the planetary albedo with their optical properties. These optical properties need to be measured and understood, ideally at multiple wavelengths. This thesis describes the ongoing development of a supercontinuum based multi-wavelength photoacoustic instrument to measure the light absorption and scattering coefficients of aerosols. Collimation techniques for supercontinuum sources using lens-based and off-axis parabolic mirror-based collimators were evaluated and it was determined that the off-axis mirror had superior collimation abilities for multi-spectral beams. A proof of concept supercontinuum-based photoacoustic instrument was developed using sequential measurements at multiple wavelengths. The instrument data were in good agreement with those from a commercial 3-wavelength photoacoustic instrument and the novel instrument had minimum detectable absorption and scattering coefficients of better than 4 Mm-1 and 21 Mm-1, respectively. The instrument however suffered from poor temporal resolution due to the sequential measurement and required the development of an aerosol delivery system to deliver a slowly varying aerosol concentration. In response, a spectral modulator has been developed to frequency encode different wavelength bands for simultaneous measurement with a photoacoustic instrumen.

  6. Retrieval and molecule sensitivity studies for the global ozone monitoring experiment and the scanning imaging absorption spectrometer for atmospheric chartography

    NASA Technical Reports Server (NTRS)

    Chance, Kelly V.; Burrows, John P.; Schneider, Wolfgang

    1991-01-01

    The Global Ozone Monitoring Experiment (GOME) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) are diode based spectrometers that will make atmospheric constituent and aerosol measurements from European satellite platforms beginning in the mid 1990's. GOME measures the atmosphere in the UV and visible in nadir scanning, while SCIAMACHY performs a combination of nadir, limb, and occultation measurements in the UV, visible, and infrared. A summary is presented of the sensitivity studies that were performed for SCIAMACHY measurements. As the GOME measurement capability is a subset of the SCIAMACHY measurement capability, the nadir, UV, and visible portion of the studies is shown to apply to GOME as well.

  7. Commissioning of the vacuum system of the KATRIN Main Spectrometer

    NASA Astrophysics Data System (ADS)

    Arenz, M.; Babutzka, M.; Bahr, M.; Barrett, J. P.; Bauer, S.; Beck, M.; Beglarian, A.; Behrens, J.; Bergmann, T.; Besserer, U.; Blümer, J.; Bodine, L. I.; Bokeloh, K.; Bonn, J.; Bornschein, B.; Bornschein, L.; Büsch, S.; Burritt, T. H.; Chilingaryan, S.; Corona, T. J.; De Viveiros, L.; Doe, P. J.; Dragoun, O.; Drexlin, G.; Dyba, S.; Ebenhöch, S.; Eitel, K.; Ellinger, E.; Enomoto, S.; Erhard, M.; Eversheim, D.; Fedkevych, M.; Felden, A.; Fischer, S.; Formaggio, J. A.; Fränkle, F.; Furse, D.; Ghilea, M.; Gil, W.; Glück, F.; Gonzalez Ureña, A.; Görhardt, S.; Groh, S.; Grohmann, S.; Grössle, R.; Gumbsheimer, R.; Hackenjos, M.; Hannen, V.; Harms, F.; Haußmann, N.; Heizmann, F.; Helbing, K.; Herz, W.; Hickford, S.; Hilk, D.; Hillen, B.; Höhn, T.; Holzapfel, B.; Hötzel, M.; Howe, M. A.; Huber, A.; Jansen, A.; Kernert, N.; Kippenbrock, L.; Kleesiek, M.; Klein, M.; Kopmann, A.; Kosmider, A.; Kovalík, A.; Krasch, B.; Kraus, M.; Krause, H.; Krause, M.; Kuckert, L.; Kuffner, B.; La Cascio, L.; Lebeda, O.; Leiber, B.; Letnev, J.; Lobashev, V. M.; Lokhov, A.; Malcherek, E.; Mark, M.; Martin, E. L.; Mertens, S.; Mirz, S.; Monreal, B.; Müller, K.; Neuberger, M.; Neumann, H.; Niemes, S.; Noe, M.; Oblath, N. S.; Off, A.; Ortjohann, H.-W.; Osipowicz, A.; Otten, E.; Parno, D. S.; Plischke, P.; Poon, A. W. P.; Prall, M.; Priester, F.; Ranitzsch, P. C.-O.; Reich, J.; Rest, O.; Robertson, R. G. H.; Röllig, M.; Rosendahl, S.; Rupp, S.; Ryšavý, M.; Schlösser, K.; Schlösser, M.; Schönung, K.; Schrank, M.; Schwarz, J.; Seiler, W.; Seitz-Moskaliuk, H.; Sentkerestiová, J.; Skasyrskaya, A.; Slezák, M.; Špalek, A.; Steidl, M.; Steinbrink, N.; Sturm, M.; Suesser, M.; Telle, H. H.; Thümmler, T.; Titov, N.; Tkachev, I.; Trost, N.; Unru, A.; Valerius, K.; Vénos, D.; Vianden, R.; Vöcking, S.; Wall, B. L.; Wandkowsky, N.; Weber, M.; Weinheimer, C.; Weiss, C.; Welte, S.; Wendel, J.; Wierman, K. L.; Wilkerson, J. F.; Winzen, D.; Wolf, J.; Wüstling, S.; Zacher, M.; Zadoroghny, S.; Zbořil, M.

    2016-04-01

    The KATRIN experiment will probe the neutrino mass by measuring the β-electron energy spectrum near the endpoint of tritium β-decay. An integral energy analysis will be performed by an electro-static spectrometer (``Main Spectrometer''), an ultra-high vacuum vessel with a length of 23.2 m, a volume of 1240 m3, and a complex inner electrode system with about 120 000 individual parts. The strong magnetic field that guides the β-electrons is provided by super-conducting solenoids at both ends of the spectrometer. Its influence on turbo-molecular pumps and vacuum gauges had to be considered. A system consisting of 6 turbo-molecular pumps and 3 km of non-evaporable getter strips has been deployed and was tested during the commissioning of the spectrometer. In this paper the configuration, the commissioning with bake-out at 300 °C, and the performance of this system are presented in detail. The vacuum system has to maintain a pressure in the 10‑11 mbar range. It is demonstrated that the performance of the system is already close to these stringent functional requirements for the KATRIN experiment, which will start at the end of 2016.

  8. A Capillary Absorption Spectrometer for Stable Carbon Isotope Ratio (13C/12C) Analysis in Very Small Samples

    SciTech Connect

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.; Newburn, Matthew K.; Moran, James J.; Alexander, M. L.; Kreuzer, Helen W.

    2012-02-06

    A capillary absorption spectrometer (CAS) suitable for IR laser isotope analysis of small CO{sub 2} samples is presented. The system employs a continuous-wave (cw) quantum cascade laser to study nearly adjacent rovibrational transitions of different isotopologues of CO{sub 2} near 2307 cm{sup -1} (4.34 {mu}m). This initial CAS system can achieve relative isotopic precision of about 10 ppm {sup 13}C, or {approx}1{per_thousand} (per mil in delta notation relative to Vienna Pee Dee Belemnite) with 20-100 picomoles of entrained sample within the hollow waveguide for CO{sub 2} concentrations {approx}400 to 750 ppm. Isotopic analyses of such gas fills in a 1-mm ID hollow waveguide of 0.8 m overall physical path length can be carried out down to {approx}2 Torr. Overall {sup 13}C/{sup 12}C ratios can be calibrated to {approx}2{per_thousand} accuracy with diluted CO{sub 2} standards. A novel, low-cost method to reduce cw-fringing noise resulting from multipath distortions in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level (peak-to-rms) after 1,000 scans are co-added in {approx}10 sec. The CAS is meant to work directly with converted CO{sub 2} samples from a Laser Ablation-Catalytic-Combustion (LA CC) micro-sampler to provide {sup 13}C/{sup 12}C ratios of small biological isolates with spatial resolutions {approx}50 {mu}m.

  9. Design of camera and spectrometer dual-use system

    NASA Astrophysics Data System (ADS)

    Qi, Yong-hong; Xue, Bin; Zhao, Yi-yi; Tao, Jin-you

    2013-08-01

    Imaging spectrometers based on prism-grating-prism (PGP) have advantage of direct vision, as a basis for the design of an optical system for a spectrometer and camera dual-use, the system can plug the light splitting element to switch between the spectrometer and camera. This paper has discussed the working principles and structure of the PGP and spectrometer, collimating and focusing lens design principles, then the design result has been presented. The spectral range of the system is 400-800nm, the pixel size of CCD used is 10um × 10um, 1010 × 1018 pixels, the object space numerical aperture is 0.1. In order to reduce the cost and eliminate aberration, collimating lens and focusing lens have symmetric structure, in order to improve the diffraction efficiency, PGP uses the volume phase holographic transmission grating. After optimization the design by ZEMAX software, the whole spectral range resolution is better than 1nm in average, the MTF at Nyquist frequency is greater than 0.7, the length of the whole system is 87mm.

  10. Dual Source Mass Spectrometer and Sample Handling System

    NASA Technical Reports Server (NTRS)

    Brinckerhoff, W. B.; Mahaffy, P. R.; Cornish, T. J.; Cheng, A. F.; Niemann, H. B.; Harpold, D. N.; Gorevan, S. P.; Rafeek, S.; Yucht, D.

    2002-01-01

    We present details of a miniature integrated time-of-flight mass spectrometer and sample handling system under development to address some of the needs for in situ sample analysis on landed missions. Additional information is contained in the original extended abstract.

  11. Optical system for high resolution spectrometer/monochromator

    DOEpatents

    Hettrick, Michael C.; Underwood, James H.

    1988-01-01

    An optical system for use in a spectrometer or monochromator employing a mirror which reflects electromagnetic radiation from a source to converge with same in a plane. A straight grooved, varied-spaced diffraction grating receives the converging electromagnetic radiation from the mirror and produces a spectral image for capture by a detector, target or like receiver.

  12. Middle infrared optoelectronic absorption systems for monitoring physiological glucose solutions

    NASA Astrophysics Data System (ADS)

    Martin, W. Blake

    Tight monitoring of the glucose levels for diabetic individuals is essential to control long-term complications. A definitive diabetes management system has yet to be developed for the diabetic. This research investigates the application of middle infrared absorption frequencies for monitoring glucose levels in biological solutions. Three frequencies were identified using a Fourier transform infrared spectrometer and correlated to changes in glucose concentrations. The 1035 +/- 1 cm-1 frequency was determined to be the best representative frequency. Other biological molecules contributed no significant interference to monitoring glucose absorption. A second frequency at 1193 cm-1 was suggested as a representative background absorption frequency, which could be used for more accurate glucose absorption values. Next, a quantum cascade laser optoelectronic absorption system was designed and developed to monitor glucose. After careful alignment and design, the system was used to monitor physiological glucose concentrations. Correlation at 1036 cm-1 with glucose changes was comparable to the previous results. The use of the background absorption frequency was verified. This frequency essentially acts as a calibrating frequency to adjust in real-time to any changes in the background absorption that may alter the accuracy of the predicted glucose value. An evanescent wave cavity ring-down spectroscopy technique was explored to monitor molecules in a biological solution. Visible light at 425 nm was used to monitor hemoglobin in control urine samples. An adsorption isotherm for hemoglobin was detectable to limit of 5.8 nM. Evanescent wave cavity ring-down spectroscopy would be useful for a glucose solution. Given an equivalent system designed for the middle infrared, the molar extinction coefficient of glucose allows for a detectable limit of 45 mg/dl for a free-floating glucose solution, which is below normal physiological concentrations. The future use of a hydrophobic

  13. Multi-wavelength measurements of aerosol optical absorption coefficients using a photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Huang, Hong-Hua; Wang, Yao; Wang, Gui-Shi; Cao, Zhen-Song; Liu, Kun; Chen, Wei-Dong; Gao, Xiao-Ming

    2014-06-01

    The atmospheric aerosol absorption capacity is a critical parameter determining its direct and indirect effects on climate. Accurate measurement is highly desired for the study of the radiative budget of the Earth. A multi-wavelength (405 nm, 532 nm, 780 nm) aerosol absorption meter based on photoacoustic spectroscopy (PAS) invovling a single cylindrical acoustic resonator is developed for measuring the aerosol optical absorption coefficients (OACs). A sensitivity of 1.3 Mm-1 (at 532 nm) is demonstrated. The aerosol absorption meter is successfully tested through measuring the OACs of atmospheric nigrosin and ambient aerosols in the suburbs of Hefei city. The absorption cross section and absorption Ångström exponent (AAE) for ambient aerosol are determined for characterizing the component of the ambient aerosol.

  14. Research on design method of spaceborne imaging spectrometer system based on telecentric optical system

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomei; Liu, Hua

    2015-08-01

    Imaging spectrometer is widely applied in the field of space remote sensing. Dispersion imaging spectrometer with prism or grating is developed rapidly and used widely. It is developed to the direction of high performance and miniaturization, such as large field of view, high resolution, small volume, etc. For meeting the demand of the development, by comparing the characteristics and the situation of development and application about the two kinds of spectrometer, based on the imaging theory of telecentric optical system, the article studied a design method of prism dispersion imaging spectrometer with telecentric Off-axis Three-Mirror imaging system. The instrument designed by using this method has smaller volume and weight than traditional instrument. It overcomes the biggest defect that traditional prism dispersion imaging spectrometer is bigger, increases its advantages in actual use in contrast to grating dispersion imaging spectrometer, and promotes the development and application of prism dispersion imaging spectrometer.

  15. Methods for Retrievals of CO2 Mixing Ratios from JPL Laser Absorption Spectrometer Flights During a Summer 2011 Campaign

    NASA Technical Reports Server (NTRS)

    Menzies, Robert T.; Spiers, Gary D.; Jacob, Joseph C.

    2013-01-01

    The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. This instrument employs CW laser transmitters and coherent detection receivers in the 2.05- micro m spectral region. The Integrated Path Differential Absorption (IPDA) method is used to retrieve weighted CO2 column mixing ratios. We present key features of the evolving LAS signal processing and data analysis algorithms and the calibration/validation methodology. Results from 2011 flights in various U.S. locations include observed mid-day CO2 drawdown in the Midwest and high spatial resolution plume detection during a leg downwind of the Four Corners power plant in New Mexico.

  16. Airborne Laser Absorption Spectrometer Measurements of CO2 Column Mixing Ratios: Source and Sink Detection in the Atmospheric Environment

    NASA Astrophysics Data System (ADS)

    Menzies, Robert T.; Spiers, Gary D.; Jacob, Joseph C.

    2016-06-01

    The JPL airborne Laser Absorption Spectrometer instrument has been flown several times in the 2007-2011 time frame for the purpose of measuring CO2 mixing ratios in the lower atmosphere. The four most recent flight campaigns were on the NASA DC-8 research aircraft, in support of the NASA ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) mission formulation studies. This instrument operates in the 2.05-μm spectral region. The Integrated Path Differential Absorption (IPDA) method is used to retrieve weighted CO2 column mixing ratios. We present key features of the CO2LAS signal processing, data analysis, and the calibration/validation methodology. Results from flights in various U.S. locations during the past three years include observed mid-day CO2 drawdown in the Midwest, also cases of point-source and regional plume detection that enable the calculation of emission rates.

  17. Airborne & Ground-based measurements of atmospheric CO2 using the 1.57-μm laser absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Sakaizawa, D.; Kawakami, S.; Nakajima, M.; Tanaka, T.; Miyamoto, Y.; Morino, I.; Uchino, O.; Asai, K.

    2009-12-01

    Greenhouse gases observing satellite (GOSAT) started the measurement of global CO2 abundances to reveal its continental inventory using two passive remote sensors. The goal that the sensor needs to be done is to achieve an 1% relative accuracy in order to reduce uncertainties of CO2 budget. Nevertheless, in the future global CO2 monitoring, more accurate measurement of global tropospheric CO2 abundances with the monthly regional scale are required to improve the knowledge of CO2 exchanges among the land, ocean, and atmosphere. In order to fulfill demands, a laser remote sensor, such as DIAL or laser absorption spectrometer (LAS), is a potential candidate of future space-based missions. Nowadays, those technologies are required to demonstrate an accuracy of the few-ppm level through airborne & ground-based measurements. We developed the prototype of the 1.57um LAS for a step of the next missions and perform it at the ground-based and airborne platform to show the properly validated performance in the framework of GOSAT validation. Our CO2 LAS is consisted of all optical fiber circuits & compact receiving /transmitting optics to achieve the portable, flexible and rigid system. The optical sources of on- and off-line are distributed feedback lasers, which are tuned at the strong and weak position of the R12 line in the (30012<-00001) absorption band. Their fiber coupled outputs are sinusoidal amplitude modulated by each EO devices with kHz rate and combined and amplified using an erbium doped fiber amplifier. Scattered signals from the hard target are collected by the 11cm receiving telescope and detected and stored into the laptop computer. After that, we evaluated the atmospheric CO2 density using the meteorological parameters and ratio between the on- and off-line signals. The resultant of the ground-based measurement of 3km optical length indicated that the statistical error of the path averaged atmospheric CO2 density is less than 2.8ppm with 25 minutes averaging

  18. Analysis and System Design Framework for Infrared Spatial Heterodyne Spectrometers

    SciTech Connect

    Cooke, B.J.; Smith, B.W.; Laubscher, B.E.; Villeneuve, P.V.; Briles, S.D.

    1999-04-05

    The authors present a preliminary analysis and design framework developed for the evaluation and optimization of infrared, Imaging Spatial Heterodyne Spectrometer (SHS) electro-optic systems. Commensurate with conventional interferometric spectrometers, SHS modeling requires an integrated analysis environment for rigorous evaluation of system error propagation due to detection process, detection noise, system motion, retrieval algorithm and calibration algorithm. The analysis tools provide for optimization of critical system parameters and components including : (1) optical aperture, f-number, and spectral transmission, (2) SHS interferometer grating and Littrow parameters, and (3) image plane requirements as well as cold shield, optical filtering, and focal-plane dimensions, pixel dimensions and quantum efficiency, (4) SHS spatial and temporal sampling parameters, and (5) retrieval and calibration algorithm issues.

  19. A Compact, Fast, Wide-Field Imaging Spectrometer System

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; VanGorp, Byron E.; White, Victor E.; Mumolo, Jason M.; Hebert, Daniel; Feldman, Martin

    2011-01-01

    We present test results from a compact, fast (F/1.4) imaging spectrometer system with a 33 degree field of view, operating in the 450-1650 nm wavelength region with an extended response InGaAs detector array. The system incorporates a simple two-mirror telescope and a steeply concave bilinear groove diffraction grating made with gray scale x-ray lithography techniques. High degree of spectral and spatial uniformity (97%) is achieved.

  20. Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

    USGS Publications Warehouse

    Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

    1989-01-01

    Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

  1. Continuous measurements of stable carbon isotopes in CO2 with a near-IR laser absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Tanaka, Kotaro; Kojima, Ryota; Takahashi, Kenshi; Tonokura, Kenichi

    2013-09-01

    A near-IR laser absorption spectrometer using a technique of wavelength modulation spectroscopy is used to measure stable carbon isotope ratios of ambient CO2 (δ13C) via the absorption lines 12CO2 R(17) (2ν1 + ν12 - ν12 + ν3) at 4978.205 cm-1 and 13CO2 P(16) (ν1 + 2ν2 + ν3) at 4978.023 cm-1. The isotope ratios are measured with a reproducibility of 0.02‰ (1σ) in a 130-s integration time over a 12-h period. The humidity effect on δ13C values has been evaluated in laboratory experiments. The δ13C values of CO2 in ambient air were measured continuously over 8 days and agreed well with those from isotope ratio mass spectrometry of canister samples. The spectrometer is thus capable of real-time, in situ measurements of stable carbon isotope ratios of CO2 under ambient conditions.

  2. Plasmon absorption modulator systems and methods

    DOEpatents

    Kekatpure, Rohan Deodatta; Davids, Paul

    2014-07-15

    Plasmon absorption modulator systems and methods are disclosed. A plasmon absorption modulator system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and a metal layer formed on a top surface of the stack of quantum well layers. A method for modulating plasmonic current includes enabling propagation of the plasmonic current along a metal layer, and applying a voltage across the stack of quantum well layers to cause absorption of a portion of energy of the plasmonic current by the stack of quantum well layers. A metamaterial switching system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and at least one metamaterial structure formed on a top surface of the stack of quantum well layers.

  3. Measurement of Urban Air Quality by an Open-Path Quantum Cascade Laser Absorption Spectrometer in Beijing During Summer 2008

    NASA Astrophysics Data System (ADS)

    Michel, A. P.; Liu, P. Q.; Yeung, J. K.; Zhang, Y.; Baeck, M. L.; Pan, X.; Dong, H.; Wang, Z.; Smith, J. A.; Gmachl, C. F.

    2009-05-01

    The 2008 Olympic Games focused attention on the air quality of Beijing, China and served as an important test-bed for developing, deploying, and testing new technologies for analysis of air quality and regional climate in urban environments. Poor air quality in urban locations has a significant detrimental effect on the health of residents while also impacting both regional and global climate change. As a result, there exists a great need for highly sensitive trace gas sensors for studying the atmosphere of the urban environment. Open-path remote sensors are of particular interest as they can obtain data on spatial scales similar to those used in regional climate models. Quantum cascade lasers (QCLs) can be designed for operation in the mid-infrared (mid-IR) with a central wavelength anywhere between 3 to 24 μm and made tunable over a wavelength interval of over 0.1 μm. The Quantum Cascade Laser Open-Path System (QCLOPS) is a mid-infrared laser absorption spectrometer that uses a tunable, thermoelectrically cooled, pulsed Daylight Solutions Inc. QCL for measurement of trace gases. The system is aimed at applications with path lengths ranging from approximately 0.1 to 1.0 km. The system is designed to continuously monitor multiple trace gases [water vapor (H2O), ozone (O3), ammonia (NH3), and carbon dioxide (CO2)] in the lower atmosphere. A field campaign from July to September 2008 in Beijing used QCLOPS to study trace gas concentrations before, during, and after the Olympic Games in an effort to capture changes induced by emissions reduction methods. QCLOPS was deployed at the Institute of Atmospheric Physics - Chinese Academy of Sciences on the roof of a two-story building, at an approximate distance of 2 miles from the Olympic National Stadium ("The Bird's Nest.") QCLOPS operated with an open-path round trip distance of approximately 75 m. The system ran with minimal human interference, twenty-four hours per day for the full campaign period. In order to

  4. Mass spectrometer. [On Space Transportation System 2 Flight

    NASA Technical Reports Server (NTRS)

    Miller, E. R.; Carignan, G. R.

    1983-01-01

    The quadrupole Mass Spectrometer of the Induced Environment Contamination Monitor (IECM) operates in the range from 2 to 150 amu. It is pointed out that the Mass Spectrometer on STS-2 performed very well. It was found that the column density of H2O effluent from the Shuttle reached a maximum of 1 x 10 to the 13th per sq cm at 7 hr, 30 min and decreased by a factor of 7.5 during the subsequent 40 hrs. The count rate response of H2O could be correlated with mission-related events, taking into account the dumping of supply water, the operation of the Flash Evaporator System, and the firing of a primary reaction control system engine.

  5. SWEPP Gamma-Ray Spectrometer System software design description

    SciTech Connect

    Femec, D.A.; Killian, E.W.

    1994-08-01

    To assist in the characterization of the radiological contents of contract-handled waste containers at the Stored Waste Examination Pilot Plant (SWEPP), the SWEPP Gamma-Ray Spectrometer (SGRS) System has been developed by the Radiation Measurements and Development Unit of the Idaho National Engineering Laboratory. The SGRS system software controls turntable and detector system activities. In addition to determining the concentrations of gamma-ray-emitting radionuclides, this software also calculates attenuation-corrected isotopic mass ratios of-specific interest. This document describes the software design for the data acquisition and analysis software associated with the SGRS system.

  6. Polarimeters and Energy Spectrometers for the ILC Beam Delivery System

    SciTech Connect

    Boogert, S.; Hildreth, M.; Kafer, D.; List, J.; Monig, K.; Moffeit, K.C.; Moortgat-Pick, G.; Riemann, S.; Schreiber, H.J.; Schuler, P.; Torrence, E.; Woods, M.; /SLAC

    2009-02-24

    This article gives an overview of current plans and issues for polarimeters and energy spectrometers in the Beam Delivery System of the ILC. It is meant to serve as a useful reference for the Detector Letter of Intent documents currently being prepared. Concepts for high precision polarization and energy measurements exist. These concepts have resulted in detailed system layouts that are included in the RDR description for the Beam Delivery System. The RDR includes both upstream and downstream polarimeters and energy spectrometers for both beams. This provides needed complementarity and redundancy for achieving the precision required, with adequate control and demonstration of systematic errors. The BDS polarimeters and energy spectrometers need to be a joint effort of the ILC BDS team and the Detector collaborations, with collaboration members responsible for the performance and accuracy of the measurements. Details for this collaboration and assigning of responsibilities remain to be worked out. There is also a demonstrated need for Detector physicists to play an active role in the design and evaluation of accelerator components that impact beam polarization and beam energy capabilities, including the polarized source and spin rotator systems. A workshop was held in 2008 on ILC Polarization and Energy measurements, which resulted in a set of recommendations for the ILC design and operation. Additional input and action is needed on these from the Detector collaborations, the Research Director and the GDE. Work is continuing during the ILC engineering design phase to further optimize the polarimeter and energy spectrometer concepts and fully implement them in the ILC. This includes consideration for alternative methods, detailed design and cost estimates, and prototype and test beam activities.

  7. Application of Pneumatic Flow Injection-Tandem Spectrometer System for Chromium Speciation

    PubMed Central

    Noroozifar, Meissam; Khorasani-Motlagh, Mozhgan; Akbari, Reza

    2007-01-01

    In this approach, a pneumatic flow injection-tandem spectrometer system, without a delivery pump, has been developed to study chromium speciation. In this system, suction force of pneumatic nebulizer of a flame atomic absorption spectrometer has been used for solution delivery through the manifold. Cr(VI) and total Cr concentrations were determined using UV-Vis and FAAS spectrometers, respectively. The Cr(III) was determined by difference. The calibration curves were linear up to 10 μg mL−1 and 20 μg mL−1 for Cr(VI) and total Cr with detection limit of 0.12 μg mL−1 and 0.07 μg mL−1 for Cr(VI) and Cr(III), respectively. The midrange precision and accuracy are less than 1.98% and ± 2.50% for two species, respectively, at a sampling rate of 100 h−1. This system was applied for the determination of the chromium species in spiked and natural waters as well as industrial waters. PMID:18273388

  8. Pneumatic flow injection analysis-tandem spectrometer system for iron speciation.

    PubMed

    Noroozifar, Meissam; Khorasani-Motlagh, Mozhgan; Akbari, Reza

    2006-01-01

    A pneumatic flow injection-tandem spectrometer system, without a delivery pump was used for the speciation of iron. In this system, the suction force of a pneumatic nebulizer of a flame absorption spectrometer was used for solution delivery through the manifold. The Fe(III) and total Fe concentrations were determined using thiocyanate ion in a UV-Vis spectrometer and a FAAS, respectively. The Fe(II) was determined by the difference. The calibration curves were linear up to 18 microg mL(-1) and 25 microg mL(-1) with detection limits of 0.09 microg mL(-1) and 0.07 microg mL(-1) for Fe(III) and Fe(II), respectively. The mid-range precision and accuracy were <2.5% and +/-3% for the two species, respectively, at a sampling rate of 120 h(-1). This system was applied for the determination of Fe(III) and Fe(II) in industrial water, natural water and spiked samples. PMID:16429790

  9. Mass specific optical absorption coefficients of mineral dust components measured by a multi wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2014-09-01

    Mass specific optical absorption coefficients of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at wavelengths of 1064, 532, 355 and 266 nm. These values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. These results are expected to have considerable importance in global radiative forcing calculations. They can also serve as reference for validating calculated wavelength dependent imaginary parts (κ) of complex refractive indices which up to now have been typically deduced from bulk phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk phase measurements.

  10. Atmospheric CO2 measurements with a 2 μm airborne laser absorption spectrometer employing coherent detection.

    PubMed

    Spiers, Gary D; Menzies, Robert T; Jacob, Joseph; Christensen, Lance E; Phillips, Mark W; Choi, Yonghoon; Browell, Edward V

    2011-05-10

    We report airborne measurements of CO(2) column abundance conducted during two 2009 campaigns using a 2.05 μm laser absorption spectrometer. The two flight campaigns took place in the California Mojave desert and in Oklahoma. The integrated path differential absorption (IPDA) method is used for the CO(2) column mixing ratio retrievals. This instrument and the data analysis methodology provide insight into the capabilities of the IPDA method for both airborne measurements and future global-scale CO(2) measurements from low Earth orbit pertinent to the NASA Active Sensing of CO(2) Emissions over Nights, Days, and Seasons mission. The use of a favorable absorption line in the CO(2) 2 μm band allows the on-line frequency to be displaced two (surface pressure) half-widths from line center, providing high sensitivity to the lower tropospheric CO(2). The measurement repeatability and measurement precision are in good agreement with predicted estimates. We also report comparisons with airborne in situ measurements conducted during the Oklahoma campaign. PMID:21556111

  11. Potassium emission absorption system. Topical report 12

    SciTech Connect

    Bauman, L.E.

    1995-04-01

    The Potassium Emission Absorption System is one of the advanced optical diagnostics developed at Mississippi State University to provide support for the demonstration of prototype-scale coal-fired combustion magnetohydrodynamic (MHD) electrical power generation. Intended for application in the upstream of an MHD flow, the system directly measures gas temperature and neutral potassium atom number density through spectroscopic emission absorption techniques. From these measurements the electron density can be inferred from a statistical equilibrium calculation and the electron conductivity in the MHD channel found by use of an electron mobility model. The instrument has been utilized for field test measurements on MHD facilities for almost a decade and has been proven to provide useful measurements as designed for MHD nozzle, channel, and diffuser test sections. The theory of the measurements, a system description, its capabilities, and field test measurement results are reported here. During the development and application of the instrument several technical issues arose which when addressed advanced the state of the art in emission absorption measurement. Studies of these issues are also reported here and include: two-wavelength measurements for particle-laden flows, potassium D-line far wing absorption coefficient, bias in emission absorption measurements arising from dirty windows and misalignments, non-coincident multiwavelength emission absorption sampling errors, and lineshape fitting for boundary layer flow profile information. Although developed for NLHD application, the instrument could be applied to any high temperature flow with a resonance line in the 300 to 800 nm range, for instance other types of flames, rocket plumes or low temperature plasmas.

  12. Fast data acquisition system for the spectrometer SMART at RIKEN

    NASA Astrophysics Data System (ADS)

    Okamura, H.

    2000-03-01

    A new data acquisition system has been introduced for experiments using the spectrometer SMART at RIKEN. It is about ten times as fast as the previous system based on the standard CAMAC (Ichihara et al., IEEE Trans. Nucl. Sci. 36 (1989) 1628), but is dedicated to the use of LeCroy FERA and FERA-compatible modules. Data are accumulated in a VME memory module through the FERA bus and then DMA-transferred to a personal computer running a free Unix-clone, Linux. Since no CPU or peripheral is required on VME, the system is very cost-effective and suitable for experiments already using FERA.

  13. Tropospheric Emission Spectrometer for the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas A.; Beer, Reinhard

    1991-01-01

    A Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) series of polar-orbiting platforms is described. TES is aimed at studying tropospheric chemistry, in particular, the exchange of gases between the surface and the atmosphere, urban and regional pollution, acid rain precursors, sources and sinks of greenhouse gases, and the interchange of gases between the troposphere and the stratosphere. TES is a high-resolution (0.025/cm) infrared Fourier transform spectrometer operating in the passive thermal-emission mode in a very wide spectral range (600 to 4350/cm; 2.3 to 16.7 microns). TES has 32 spatial pixels in each of four optically conjugated linear detector arrays, each optimized for a different spectral region.

  14. The Monitor online system of the OPERA muon magnetic spectrometer

    NASA Astrophysics Data System (ADS)

    Ugolino, U.; Ambrosio, M.; Acquafredda, R.; Masone, V.

    2008-06-01

    The OPERA muon magnetic spectrometer has been designed for muon detection, tracking and timing. The 44 bakelite Resistive Chambers (RPC) planes, imbibed inside the magnet iron slabs, must provide the tracking of the muon curved in the magnetic field to ease the momentum and charge measurement provided by the HPT. Furthermore, it provides the momentum for muons stopping in the iron. RPC signals will be also used as start of drift tube acquisition thanks to the very good time resolution of RPC detectors. Due to the required performances the tracking detector must be fully efficient and stable. In this conditions an online monitor is mandatory to continuously control stability of run conditions. We report the main characteristics and performances of the monitor system for the OPERA spectrometer and capabilities of the software developed for settings and data acquisition.

  15. Cavity BPM System Tests for the ILC Spectrometer

    SciTech Connect

    Slater, M.

    2007-12-21

    The main physics program of the International Linear Collider (ILC) requires a measurement of the beam energy at the interaction point with an accuracy of 10{sup -4} or better. To achieve this goal a magnetic spectrometer using high resolution beam position monitors (BPMs) has been proposed. This paper reports on the cavity BPM system that was deployed to test this proposal. We demonstrate sub-micron resolution and micron level stability over 20 hours for a 1 m long BPM triplet. We find micron-level stability over 1 hour for 3 BPM stations distributed over a 30 m long baseline. The understanding of the behavior and response of the BPMs gained from this work has allowed full spectrometer tests to be carried out.

  16. LONG PATH DIFFERENTIAL OPTICAL ABSORPTION SPECTROMETER AND EPA-APPROVED FIXED POINT METHODS INTERCOMPARISON

    EPA Science Inventory

    Differential optical absorption spectrometry (DOAS) has been used by a number of investigators over the past 10 years to measure a wide range of gaseous air pollutants. ecently OPSIS AB, Lund, Sweden, has developed and made commercially available DOAS instrument that has a number...

  17. Analysis of airborne imaging spectrometer data for the Ruby Mountains, Montana, by use of absorption-band-depth images

    NASA Technical Reports Server (NTRS)

    Brickey, David W.; Crowley, James K.; Rowan, Lawrence C.

    1987-01-01

    Airborne Imaging Spectrometer-1 (AIS-1) data were obtained for an area of amphibolite grade metamorphic rocks that have moderate rangeland vegetation cover. Although rock exposures are sparse and patchy at this site, soils are visible through the vegetation and typically comprise 20 to 30 percent of the surface area. Channel averaged low band depth images for diagnostic soil rock absorption bands. Sets of three such images were combined to produce color composite band depth images. This relative simple approach did not require extensive calibration efforts and was effective for discerning a number of spectrally distinctive rocks and soils, including soils having high talc concentrations. The results show that the high spectral and spatial resolution of AIS-1 and future sensors hold considerable promise for mapping mineral variations in soil, even in moderately vegetated areas.

  18. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for measurements of atmospheric ammonia

    NASA Astrophysics Data System (ADS)

    Ellis, R. A.; Murphy, J. G.; Pattey, E.; van Haarlem, R.; O'Brien, J. M.; Herndon, S. C.

    2009-12-01

    A compact, fast-response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for measurements of ammonia has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 0.5 L multiple pass absorption cell with an effective path length of 76 m. Detection is achieved using a thermoelectrically cooled Mercury Cadmium Telluride (HgCdTe) infrared detector. A novel sampling inlet was used, consisting of a short, heated, quartz tube with a hydrophobic coating to minimize the adsorption of ammonia to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles, and additional ports for delivering ammonia-free background air and calibration gas standards. This instrument has been found to have a detection limit of 0.23 ppb at 1 Hz. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser Absorption Spectrometer (TDLAS) during a laboratory intercomparison. The effect of humidity and heat on the surface interaction of ammonia with sample tubing was investigated at mixing ratios ranging from 30-1000 ppb. Humidity was seen to worsen the ammonia time response and considerable improvement was observed when using a heated sampling line. A field intercomparison of the QC-TILDAS with a modified Thermo 42CTL chemiluminescence based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE) in the rural town of Egbert, ON between May-July 2008. Background tests and calibrations using two different permeation tube sources and an ammonia gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation with 1 min time resolution (R2=0.93) between the two instruments at the beginning of the study, when regular background subtraction was applied to the QC

  19. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for measurements of atmospheric ammonia

    NASA Astrophysics Data System (ADS)

    Ellis, R. A.; Murphy, J. G.; Pattey, E.; van Haarlem, R.; O'Brien, J. M.; Herndon, S. C.

    2010-03-01

    A compact, fast-response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for measurements of ammonia (NH3) has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 0.5 L multiple pass absorption cell with an effective path length of 76 m. Detection is achieved using a thermoelectrically-cooled Mercury Cadmium Telluride (HgCdTe) infrared detector. A novel sampling inlet was used, consisting of a short, heated, quartz tube with a hydrophobic coating to minimize the adsorption of NH3 to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles, and additional ports for delivering NH3-free background air and calibration gas standards. The level of noise in this instrument has been found to be 0.23 ppb at 1 Hz. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser Absorption Spectrometer (TDLAS) during a laboratory intercomparison. The effect of humidity and heat on the surface interaction of NH3 with sample tubing was investigated at mixing ratios ranging from 30-1000 ppb. Humidity was seen to worsen the NH3 time response and considerable improvement was observed when using a heated sampling line. A field intercomparison of the QC-TILDAS with a modified Thermo 42CTL chemiluminescence-based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE) in the rural town of Egbert, ON between May-July 2008. Background tests and calibrations using two different permeation tube sources and an NH3 gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation at 1 min time resolution (R2 = 0.93) between the two instruments at the beginning of the study, when regular background subtraction was applied to the QC-TILDAS. An overall good

  20. Characterizing a Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC-TILDAS) for Measurements of Atmospheric Ammonia

    NASA Astrophysics Data System (ADS)

    Ellis, R.; Murphy, J. G.; van Haarlem, R.; Pattey, E.; O'Brien, J.

    2009-05-01

    A compact, fast response Quantum Cascade Tunable Infrared Laser Differential Absorption Spectrometer (QC- TILDAS) for measurements of ammonia has been evaluated under both laboratory and field conditions. Absorption of radiation from a pulsed, thermoelectrically cooled QC laser occurs at reduced pressure in a 76 m path length, 0.5 L volume multiple pass absorption cell. Detection is achieved using a thermoelectrically cooled HgCdTe infrared detector. A novel sampling technique was used, consisting of a short, heated, quartz inlet with a hydrophobic coating to minimize the adsorption of ammonia to surfaces. The inlet contains a critical orifice that reduces the pressure, a virtual impactor for separation of particles and additional ports for delivering ammonia free background air and calibration gas standards. This instrument has been found to have a detection limit of 0.3 ppb with a time resolution of 1 s. The sampling technique has been compared to the results of a conventional lead salt Tunable Diode Laser (TDL) absorption spectrometer during a laboratory intercomparison. Various lengths and types of sample inlet tubing material, heated and unheated, under dry and ambient humidity conditions with ammonia concentrations ranging from 10-1000 ppb were investigated. Preliminary analysis suggests the time response improves with the use of short, PFA tubing sampling lines. No significant improvement was observed when using a heated sampling line and humidity was seen to play an important role on the bi-exponential decay of ammonia. A field intercomparison of the QC-TILDAS with a modified Thermo 42C chemiluminescence based analyzer was also performed at Environment Canada's Centre for Atmospheric Research Experiments (CARE) in the rural town of Egbert, ON between May-July 2008. Background tests and calibrations using two different permeation tube sources and an ammonia gas cylinder were regularly carried out throughout the study. Results indicate a very good correlation

  1. Moessbauer Spectrometer in the PXI/CompactPCI Modular System

    SciTech Connect

    Pechousek, Jiri; Mashlan, Miroslav; Zboril, Radek

    2005-04-26

    Two commercially available modules, a digital oscilloscope (NI 5102) and a function generator (NI 5401) in the PXI (PCI eXtension for Instrumentation) or PCI standard from National Instruments Inc., supported by the driver software, have been used for building a computer-based Moessbauer spectrometer. The RTSI (Real-Time System Integration) bus is used for synchronizing the accumulation of the detector impulses to the Moessbauer spectrum with velocity of the 'source-sample' relative motion. The amplitude selection of the impulses from the detector output is based on the use of the Waveform Peak Detection.vi function. This function is available in the graphical programming environment LabVIEW 7 Express which serves for an implementation of the virtual instrument of the Moessbauer spectrometer. Moessbauer spectra can be accumulated in the constant and variable velocity modes; moreover, there is a possibility to register gamma-ray spectra in the multichannel analyzer mode. Two types of the detectors (a NaI(Tl) and a resonance scintillation detector) have been used with the new Moessbauer spectrometer.

  2. Infrared absorption of gaseous CH{sub 2}BrOO detected with a step-scan Fourier-transform absorption spectrometer

    SciTech Connect

    Huang, Yu-Hsuan; Lee, Yuan-Pern

    2014-10-28

    CH{sub 2}BrOO radicals were produced upon irradiation, with an excimer laser at 248 nm, of a flowing mixture of CH{sub 2}Br{sub 2} and O{sub 2}. A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to record temporally resolved infrared (IR) absorption spectra of reaction intermediates. Transient absorption with origins at 1276.1, 1088.3, 961.0, and 884.9 cm{sup −1} are assigned to ν{sub 4} (CH{sub 2}-wagging), ν{sub 6} (O–O stretching), ν{sub 7} (CH{sub 2}-rocking mixed with C–O stretching), and ν{sub 8} (C–O stretching mixed with CH{sub 2}-rocking) modes of syn-CH{sub 2}BrOO, respectively. The assignments were made according to the expected photochemistry and a comparison of observed vibrational wavenumbers, relative IR intensities, and rotational contours with those predicted with the B3LYP/aug-cc-pVTZ method. The rotational contours of ν{sub 7} and ν{sub 8} indicate that hot bands involving the torsional (ν{sub 12}) mode are also present, with transitions 7{sub 0}{sup 1}12{sub v}{sup v} and 8{sub 0}{sup 1}12{sub v}{sup v}, v = 1–10. The most intense band (ν{sub 4}) of anti-CH{sub 2}BrOO near 1277 cm{sup −1} might have a small contribution to the observed spectra. Our work provides information for directly probing gaseous CH{sub 2}BrOO with IR spectroscopy, in either the atmosphere or laboratory experiments.

  3. Forward hadron calorimeter of European hybrid spectrometer monitoring system

    SciTech Connect

    Boratave, M.; Datsko, N.A.; David, J.; Ivanyushenkov, Y.M.; Kistenoev, E.P.; Vlasov, E.V.

    1985-11-01

    The light-monitoring system of the forward neutral-hadron calorimeter of the European hybrid spectrometer is described. A general block diagram of the system, the functional relationships of the modules, and the ideology of the mathematical support are presented. The calorimeter records neutral particles in momentum range of 10-400 MeV/c. The calorimeter consists of 200 identical counters in modules of four each in a 10 X 20 matrix. The counters are made from plastic scintillators interlayed by steel plates. Light is collected by means of a rod reemitter admitted along the counter axis.

  4. Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) CHEM Satellite

    NASA Technical Reports Server (NTRS)

    Beer, R.; Glavich, T.; Rider, D.

    2000-01-01

    The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier transform spectrometer scheduled to be launched into polar sun-synchronous orbit on the Earth Observing System (EOS) CHEM satellite in December 2002.

  5. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  6. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  7. A Weld Defects Detection System Based on a Spectrometer

    PubMed Central

    Bebiano, Daniel; Alfaro, Sadek C. A.

    2009-01-01

    Improved product quality and production methods, and decreased production costs are important objectives of industries. Welding processes are part of this goal. There are many studies about monitoring and controlling welding process. This work presents a non-intrusive on-line monitoriment system and some algorithms capable of detecting GTAW weld defects. Some experiments were made to simulate weld defects by disturbing the electric arc. The data comes from a spectrometer which captures perturbations on the electric arc by the radiation emission of chosen lines. Algorithms based on change detection methods are used to indicate the presence and localization of those defects. PMID:22574049

  8. FTIR spectrometer with solid-state drive system

    DOEpatents

    Rajic, Slobodan; Seals, Roland D.; Egert, Charles M.

    1999-01-01

    An FTIR spectrometer (10) and method using a solid-state drive system with thermally responsive members (27) that are subject to expansion upon heating and to contraction upon cooling. Such members (27) are assembled in the device (10) so as to move an angled, reflective surface (22) a small distance. The sample light beam (13) is received at a detector (24) along with a reference light beam (13) and there it is combined into a resulting signal. This allows the "interference" between the two beams to occur for spectral analysis by a processor (29).

  9. A prototype stationary Fourier transform spectrometer for near-infrared absorption spectroscopy.

    PubMed

    Li, Jinyang; Lu, Dan-feng; Qi, Zhi-mei

    2015-09-01

    A prototype stationary Fourier transform spectrometer (FTS) was constructed with a fiber-coupled lithium niobate (LiNbO3) waveguide Mach-Zehnder interferometer (MZI) for the purpose of rapid on-site spectroscopy of biological and chemical measurands. The MZI contains push-pull electrodes for electro-optic modulation, and its interferogram as a plot of intensity against voltage was obtained by scanning the modulating voltage from -60 to +60 V in 50 ms. The power spectrum of input signal was retrieved by Fourier transform processing of the interferogram combined with the wavelength dispersion of half-wave voltage determined for the MZI used. The prototype FTS operates in the single-mode wavelength range from 1200 to 1700 nm and allows for reproducible spectroscopy. A linear concentration dependence of the absorbance at λmax = 1451 nm for water in ethanolic solution was obtained using the prototype FTS. The near-infrared spectroscopy of solid samples was also implemented, and the different spectra obtained with different materials evidenced the chemical recognition capability of the prototype FTS. To make this prototype FTS practically applicable, work on improving its spectral resolution by increasing the maximum optical path length difference is in progress. PMID:26414526

  10. Light absorption coefficient measurement of SOA using a UV-Visible spectrometer connected with an integrating sphere

    NASA Astrophysics Data System (ADS)

    Zhong, Min; Jang, Myoseon

    2011-08-01

    A method for measuring an aerosol light absorption coefficient ( B a) has been developed using a conventional UV-visible spectrometer equipped with an integrating sphere covering a wide range of wavelengths (280-800 nm). The feasibility of the proposed method was evaluated in both the transmittance mode (TUV-IS) and the reflective mode (RUV-IS) using the reference aerosol known for the cross-sectional area. The aerosol was collected on a conventional filter and measured for B a values. The resulting RUV-IS method was applied to measure light absorption of secondary organic aerosol (SOA). SOA was produced through photooxidation of different precursor hydrocarbons such as toluene, d-limonene and α-pinene in the presence of NO x (60-70 ppb) and inorganic seed aerosol using a 2-m 3 indoor Teflon film chamber. Of the three precursor hydrocarbons, the B a value of toluene SOA (0.574 m 2 g -1 at 350 nm) was the highest compared with B a values for α-pinene SOA (0.029 m 2 g -1) and d-limonene SOA (0.038 m 2 g -1). When d-limonene SOA or toluene SOA was internally mixed with neutral [(NH 4) 2SO 4] or acidic inorganic seed (NH 4HSO 4:H 2SO 4 = 1:1 by mole), the SOA showed 2-3 times greater B a values at 350 nm than the SOA with no seed. Aerosol aging with a light source for this study reduced B a values of SOA (e.g., on average 10% for toluene SOA and 30% for d-limonene SOA within 4 h). Overall, weak absorption appeared for chamber-generated SOA over wavelengths ranging from 280 to 550 nm, which fall into the sunlight spectrum.

  11. High sensitivity liquid phase measurements using broadband cavity enhanced absorption spectroscopy (BBCEAS) featuring a low cost webcam based prism spectrometer.

    PubMed

    Qu, Zhechao; Engstrom, Julia; Wong, Donald; Islam, Meez; Kaminski, Clemens F

    2013-11-01

    Cavity enhanced techniques enable high sensitivity absorption measurements in the liquid phase but are typically more complex, and much more expensive, to perform than conventional absorption methods. The latter attributes have so far prevented a wide spread use of these methods in the analytical sciences. In this study we demonstrate a novel BBCEAS instrument that is sensitive, yet simple and economical to set up and operate. We use a prism spectrometer with a low cost webcam as the detector in conjunction with an optical cavity consisting of two R = 0.99 dielectric mirrors and a white light LED source for illumination. High sensitivity liquid phase measurements were made on samples contained in 1 cm quartz cuvettes placed at normal incidence to the light beam in the optical cavity. The cavity enhancement factor (CEF) with water as the solvent was determined directly by phase shift cavity ring down spectroscopy (PS-CRDS) and also by calibration with Rhodamine 6G solutions. Both methods yielded closely matching CEF values of ~60. The minimum detectable change in absorption (αmin) was determined to be 6.5 × 10(-5) cm(-1) at 527 nm and was limited only by the 8 bit resolution of the particular webcam detector used, thus offering scope for further improvement. The instrument was used to make representative measurements on dye solutions and in the determination of nitrite concentrations in a variation of the widely used Griess Assay. Limits of detection (LOD) were ~850 pM for Rhodamine 6G and 3.7 nM for nitrite, respectively. The sensitivity of the instrument compares favourably with previous cavity based liquid phase studies whilst being achieved at a small fraction of the cost hitherto reported, thus opening the door to widespread use in the community. Further means of improving sensitivity are discussed in the paper. PMID:24049768

  12. A Data Aquisition System for the Crystal Ball Spectrometer

    NASA Astrophysics Data System (ADS)

    McDonald, S.

    1997-10-01

    A new Baryon Spectroscopy program has been initiated at the Brookhaven AGS facility with the Crystal Ball Spectrometer. This spectrometer, which consists of 672 NaI(Tl) crystals over most of a 4π geometry, was originally built for studies of the excited charmonium spectrum at SLAC, and also used later at DESY. The readout from all crystals was originally multiplexed through a single ADC, with typical readout rates of about 5 Hz. There were separate digitizations into low-energy and high-energy ranges. For the AGS program, a new data readout system has been designed. The electronic readout of each of the 80 minor triangles of 5 or 9 crystals is now multiplexed through a FERA ADC system into a VME dual-port memory. The software readout and control was done by the CEBAF Online Data Acquisition system (CODA). For a typical event size of 1 kbyte, a maximum readout rate of 1.2 kHz was achieved. An interface with PAW was also implemented for on-line monitoring of the beam, detector, and physics events. A description of these components will be presented.

  13. Miniaturized electronic system for the Planetary Integrated Camera-Spectrometer

    NASA Astrophysics Data System (ADS)

    Soll, Stanley L.; Graham, Richard; Ramirez, Luis J.

    1994-09-01

    This paper discusses the design, and implementation of a miniaturized electronic system for the Planetary Integrated Camera Spectrometer (PICS). The PICS electronics demonstrate the application of Field Programmable Gate Arrays (FPGAs) and of analog hybrid technology to space flight multi-spectral systems. A discussion of the electronic system design illustrates how signals from a multi-sensor instrument containing an UV CCD, two visible CCDs, and a near-IR focal plane assembly can be processed through a common set of electronics. Following the system design discussion, the actual electronic design will be presented. Each miniaturized module will be discussed as to functionality and performance. The test setup for bench checkout of a cooled CCD and an IR FPA, including results with breadboard electronics and with the hybrids are also described.

  14. Dilution cycle control for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    A dilution cycle control system for an absorption refrigeration system is disclosed. The control system includes a time delay relay for sensing shutdown of the absorption refrigeration system and for generating a control signal only after expiration of a preselected time period measured from the sensed shutdown of the absorption refrigeration system, during which the absorption refrigeration system is not restarted. A dilution cycle for the absorption refrigeration system is initiated in response to generation of a control signal by the time delay relay. This control system is particularly suitable for use with an absorption refrigeration system which is frequently cycled on and off since the time delay provided by the control system prevents needless dilution of the absorption refrigeration system when the system is turned off for only a short period of time and then is turned back on.

  15. Thermal model of solar absorption HVAC systems

    SciTech Connect

    Bergquam, J.B.; Brezner, J.M. |

    1995-11-01

    This paper presents a thermal model that describes the performance of solar absorption HVAC systems. The model considers the collector array, the building cooling and heating loads, the absorption chiller and the high temperature storage. Heat losses from the storage tank and piping are included in the model. All of the results presented in the paper are for an array of flat plate solar collectors with black chrome (selective surface) absorber plates. The collector efficiency equation is used to calculate the useful heat output from the array. The storage is modeled as a non-stratified tank with polyurethane foam insulation. The system is assumed to operate continuously providing air conditioning during the cooling season, space heating during the winter and hot water throughout the year. The amount of heat required to drive the chiller is determined from the coefficient of performance of the absorption cycle. Results are presented for a typical COP of 0.7. The cooling capacity of the chiller is a function of storage (generator) temperature. The nominal value is 190 F (88 C) and the range of values considered is 180 F (82 C) to 210 F (99 C). Typical building cooling and heating loads are determined as a function of ambient conditions. Performance results are presented for Sacramento, CA and Washington, D.C. The model described in the paper makes use of National Solar Radiation Data Base (NSRDB) data and results are presented for these two locations. The uncertainties in the NSRDB are estimated to be in a range of 6% to 9%. This is a significant improvement over previously available data. The model makes it possible to predict the performance of solar HVAC systems and calculate quantities such as solar fraction, storage temperature, heat losses and parasitic power for every hour of the period for which data are available.

  16. Spatial mapping of greenhouse gases using laser absorption spectrometers at local scales of interest

    SciTech Connect

    Dobler, Jeremy

    2015-09-22

    This presentation provides and overview of the development off the GreenLITE system for spatial mapping of atmospheric CO2. The original system was developed for supporting MRV activities for ground carbon storage facilities and has since been expanded to cover larger areas and other applications.

  17. Arrayed Micro-Ring Spectrometer System and Method of Use

    NASA Technical Reports Server (NTRS)

    Choi, Sang H. (Inventor); Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

    2012-01-01

    A spectrometer system includes an array of micro-zone plates (MZP) each having coaxially-aligned ring gratings, a sample plate for supporting and illuminating a sample, and an array of photon detectors for measuring a spectral characteristic of the predetermined wavelength. The sample plate emits an evanescent wave in response to incident light, which excites molecules of the sample to thereby cause an emission of secondary photons. A method of detecting the intensity of a selected wavelength of incident light includes directing the incident light onto an array of MZP, diffracting a selected wavelength of the incident light onto a target focal point using the array of MZP, and detecting the intensity of the selected portion using an array of photon detectors. An electro-optic layer positioned adjacent to the array of MZP may be excited via an applied voltage to select the wavelength of the incident light.

  18. Spatial mapping of greenhouse gases using laser absorption spectrometers at local scales of interest

    NASA Astrophysics Data System (ADS)

    Dobler, Jeremy; Zaccheo, T. S.; Blume, Nathan; Braun, Michael; Botos, Chris; Pernini, Timothy G.

    2015-10-01

    Over the past two years a new system capable of measuring the 2-D spatial distribution of atmospheric CO2 over areas on the order of 1 km2 and time scales of a few minutes, has been developed and demonstrated. The Greenhouse gas Laser Imaging Tomography Experiment (GreenLITE) - developed under a cooperative agreement with the National Energy Technology Laboratory (NETL) of the U.S. Department of Energy (DOE) - attempts to improve monitoring capabilities of Ground Carbon Storage (GCS) sites. GreenLITE sensors are based on an intensity modulated continuous wave (IM-CW) approach developed at ITT (now part of Harris Corp.) in 2004. The GreenLITE system recently completed a remote deployment of nearly 4,000 hours at a GCS site in Illinois. It provided continuous, real-time spatial distribution maps of CO2 via an open web-based interface from February to August 2015. In early 2015 we began work on a new implementation of GreenLITE capable of providing similar measurements over a 25 km2 area and are planning to test the system over a 5 km range late summer 2015. If successful the system will be deployed in an urban environment late 2015, demonstrating the utility of real-time 2-D spatial mapping of CO2 concentrations at this scale. This paper will review the concept for this new measurement capability, including results from the 1 km system. Ultimately, the measurement concept can be adapted to other greenhouse gases such as CH4 and NO2.

  19. Counterflow absorber for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

  20. Abundances in 8 QSO Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Lauroesch, James Thomas

    1995-01-01

    An analysis is given of high resolution observations of metal-absorption line systems in the spectra of 4 QSOs made with the echelle spectrograph on the Mayall 4-meter telescope at Kitt Peak National Observatory. High spectral -resolution (9 to 18 km cdot s^{ -1}) observations were obtained for the QSOs S5 0014 + 813, H 0913 + 072, B2 1225 + 317, and HS 1946 + 7658; column densities were derived for the heavy element line systems. Abundances and/or abundance ratios have been determined for 8 systems and a variety of H I column densities in the redshift range 1-3.4 are probed. The systems studies are generally relatively poor in heavy elements, and appear to be similar in heavy element abundances to the gas out of which the Galactic halo stars of similar metallicity formed. Indications of the halo star-abundance sample include the observed ratios of (N/Si), (Al/Si), and (Mn/Fe). The existence of associated H II regions is inferred for a number of damped systems, and it is suggested that the possibly significant amount of gas in H II regions in damped Lyman-alpha systems can be constrained by the comparison of the column densities of O I, N I, N II, Si II, and S II in these systems. The ratio of N(Al II)/N(Al III) is shown to be a poor indicator of the amount of ionized gas in some cases. The abundances of Si as determined from N(Si II)/N(H I) suggest that there is a relatively rapid decrease in abundances in these systems at z _sp{ ~}> 2. Such a decrease in abundances is what would be expected if the galactic (thin) disks did not form before redshifts of z {~} 2. The use of Si II is important, since the weakness of the Zn II lines at low abundances (due to the low relative abundance of Zn compared to elements such as Si) will result in few detections, and in upper limits that are difficult to interpret. The observed drop in abundances is consistent with the decrease in number of heavy-element absorption systems at high redshifts, a result that is found in

  1. Wavelength-Dependent Optical Absorption Properties of Artificial and Atmospheric Aerosol Measured by a Multi-Wavelength Photoacoustic Spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Bozóki, Z.; Szabó, G.

    2014-12-01

    Various aspects of the photoacoustic (PA) detection method are discussed from the point of view of developing it into a routine tool for measuring the wavelength-dependent optical absorption coefficient of artificial and atmospheric aerosol. The discussion includes the issues of calibration, cross-sensitivity to gaseous molecules, background PA signal subtraction, and size-dependent particle losses within the PA system. The results in this paper are based on a recently developed four-wavelength PA system, which has operational wavelengths in the near-infrared, in the visible, and in the ultraviolet. The measured spectra of artificial and atmospheric aerosol prove the outstanding applicability of the presented PA system.

  2. Spray generators for absorption refrigeration systems

    DOEpatents

    Sibley, Howard W.

    1979-06-19

    A spray generator for an absorption refrigeration system that includes a heat exchanger comprised of a multiplicity of variably spaced heat exchange tubes. The tubes are spaced close together near the top of the heat exchanger and spaced more widely apart near the bottom of the heat exchanger. Dilute absorbent solution is sprayed down through the heat exchanger. The close nesting of the tubes in the top portion of the heat exchanger retards liquid flow and aids heating of the solution. The wide spacing of the tubes in the lower section of the heat exchanger facilitate vapor flow out of the heat exchanger and eliminates liquid "blow-off". The top tubes are covered by a baffle to prevent the liquid solution from splashing out of the heat exchanger off of these top tubes.

  3. The research of data acquisition system for Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Cui, Xiao; Guo, Pan; Zhang, Yinchao; Chen, Siying; Chen, He; Chen, Wenbo

    2011-11-01

    Raman spectrometer has been widely used as an identification tool for analyzing material structure and composition in many fields. However, Raman scattering echo signal is very weak, about dozens of photons at most in one laser plus signal. Therefore, it is a great challenge to design a Raman spectrum data acquisition system which could accurately receive the weak echo signal. The system designed in this paper receives optical signals with the principle of photon counter and could detect single photon. The whole system consists of a photoelectric conversion module H7421-40 and a photo counting card including a field programmable gate array (FPGA) chip and a PCI9054 chip. The module H7421-40 including a PMT, an amplifier and a discriminator has high sensitivity on wavelength from 300nm to 720nm. The Center Wavelength is 580nm which is close to the excitation wavelength (532nm), QE 40% at peak wavelength, Count Sensitivity is 7.8*105(S-1PW-1) and Count Linearity is 1.5MHZ. In FPGA chip, the functions are divided into three parts: parameter setting module, controlling module, data collection and storage module. All the commands, parameters and data are transmitted between FPGA and computer by PCI9054 chip through the PCI interface. The result of experiment shows that the Raman spectrum data acquisition system is reasonable and efficient. There are three primary advantages of the data acquisition system: the first one is the high sensitivity with single photon detection capability; the second one is the high integrated level which means all the operation could be done by the photo counting card; and the last one is the high expansion ability because of the smart reconfigurability of FPGA chip.

  4. Smithsonian stratospheric far-infrared spectrometer and data reduction system

    NASA Technical Reports Server (NTRS)

    Johnson, D. G.; Jucks, K. W.; Traub, W. A.; Chance, K. V.

    1995-01-01

    The Smithsonian far-infrared spectrometer (FIRS) is a remote sensing Fourier transform spectrometer that measures the mid- and far-infrared thermal emission spectrum of the stratosphere from balloon and aircraft platforms. The spectrometer has had nine successful balloon flights from 1987 to 1994, flying at float altitudes of 36 - 39 km and collecting 131 hours of midlatitude stratospheric limb spectra. The spectrometer also flew on a NASA CD-8 aircraft, as part of the second Airborne Arctic Stratospheric Expedition (AASE-2), collecting 140 hours of overhead spectra at latitudes ranging from the equator to the north pole. We present here a brief description of the instrument, a discussion of data reduction procedures, an estimation of both random and systematic errors, an outline of the procedure for retrieving mixing ratio profiles, and an explanation of the method of deriving temperature and pressure from the far- and mid-infrared spectra.

  5. Spectroscopic Character and Spatial Distribution of Hydroxyl and Water Absorption Features Measured on the Lunar Surface by the Moon Mineralogy Mapper Imaging Spectrometer on Chandrayaan-1

    NASA Astrophysics Data System (ADS)

    Green, R. O.; Pieters, C. M.; Goswami, J.; Clark, R. N.; Annadurai, M.; Boardman, J. W.; Buratti, B. J.; Combe, J.; Dyar, M. D.; Head, J. W.; Hibbitts, C.; Hicks, M.; Isaacson, P.; Klima, R. L.; Kramer, G. Y.; Kumar, S.; Livo, K. E.; Lundeen, S.; Malaret, E.; McCord, T. B.; Mustard, J. F.; Nettles, J. W.; Petro, N. E.; Runyon, C. J.; Staid, M.; Sunshine, J. M.; Taylor, L. A.; Tompkins, S.; Varanasi, P.

    2009-12-01

    The Moon Mineralogy Mapper imaging spectrometer on Chandrayaan-1 has a broad spectral range from 430 to 3000 nm. By design, the range was specified to extend to 3000 nm to allow for possible detection of trace volatile compounds that possess absorption bands near 3000 nm. Soon after acquisition and calibration of a large fraction of the lunar surface in early February 2009, absorption features in the 2700 to 3000 nm region were detected over unexpectedly large regional areas. This extraordinary discovery has withstood extensive re-analysis and falsification efforts. We have concluded these absorption features are fundamentally present in the M3 measurements and are indicators of extensive hydroxyl and water-bearing materials occurring on the surface of the Moon. Based on current analyses, these absorption features appear strongest at high latitudes, but also occur in association with several fresh feldspathic craters. Interestingly, the distribution of these absorption features are not directly correlated with existing neutron spectrometer hydrogen abundance data for the sunlight surface. This may indicate that the formation and retention of hydroxyl and water is an active process largely restricted to the upper most surface. We present the detailed spectroscopic character of these absorption features in the 2700 to 3000 nm spectral region, including selected examples through all levels of measurement processing from raw data to calibrated apparent surface reflectance. In summary we show the measured strength and latitudinal distribution of the absorptions as well as selected localized occurrences in association with fresh feldspathic craters. The presence of hydroxyl and water bearing material over extensive regions of the lunar surface provides a new and unexpected source of volatiles. Options for harvesting these elements directly from the regolith may provide an alternate supply of volatiles for long term human exploration objectives.

  6. Portable LN 2 gamma-ray spectrometer system

    NASA Astrophysics Data System (ADS)

    McElhaney, S. A.; Brogle, R.; Guim, A.; Gerrish, A. M.; Lasché, G. P.; Nobel, J.; Pauly, S.

    1999-02-01

    The purpose of this program is to design and demonstrate a highly sensitive, portable spectrometer for detecting and identifying trace amounts of nuclear materials in a broad range of nonproliferation scenarios. A high-efficiency 100% n-type germanium (Ge) detector is combined with a special liquid nitrogen dewar designed to accommodate an active Compton suppression shield. The added collimation capability is required in order to be able to identify localized sources that may be obscured by background radiation. These components are complemented by the addition of a newly developed state-of-the-art multichannel analyzer (MCA) capable of 64×16 000 channel acquisition and electronic Compton suppression. The entire system fits into a watertight case that could be stored below the seat of commercial airliners. The unit has 2.74 keV resolution at 1.33 MeV, 8.5° angular resolution, low-power, >25 h full-time battery life, and operations between 35 keV< E<3 MeV.

  7. Design of a small angle spectrometer: Application to food systems

    NASA Astrophysics Data System (ADS)

    Alexander, Marcela

    This thesis describes the design of a new class of spectrometer developed for the study of light scattering phenomena at very low angles. Its detection system is a state of the art Charged Couple Device (CCD) camera of short data gathering time and very high sensitivity and dynamic range. The Small Angle Light Scattering technique in this work is shown to be a useful tool for determining size distributions of particles whose diameter is larger than approximately 300 nm. For particles smaller than this size, the technique is a sensitive probe of Rayleigh scattering. The advantages presented by the use of a solid state camera enables the study of relatively fast dynamic phenomena such as aggregation. In this particular work, we followed the aggregation of casein micelles caused by the addition of rennet, and the aggregation of β- Lactoglobulin stabilized oil in water emulsions caused by the addition of CaCl2. For this last case, a discrete inversion technique, incorporating the Mie scattering theory, was applied to obtain size distribution histograms of the emulsion droplets as a function of aggregation time.

  8. Differential optical absorption spectrometer measurement of NO 2, SO 2, O 3, HCHO and aromatic volatile organics in ambient air of Kaohsiung Petroleum Refinery in Taiwan

    NASA Astrophysics Data System (ADS)

    Chiu, Kong Hwa; Sree, Usha; Hong Tseng, Sen; Wu, Chien-Hou; Lo, Jiunn-Guang

    UV-differential optical absorption spectrometer (DOAS) technique is considered as a promising technique to detect gaseous pollutants and was applied to conduct one-week continuous measurements in the Chinese Petroleum (CPC) refinery plant located in Lin Yuan industrial park of Kaohsiung, Southern Taiwan. With the combination of local meteorological information, including solar radiation, wind direction and speed, the results showed that the concentrations of aromatic compounds and formaldehyde (HCHO) were higher at night while the values of ozone, NO 2 and SO 2 were high during the day. The major source of aromatics was the aromatic extraction unit in the refinery while NO 2 and SO 2 were mainly emitted from chimneys with not very high average concentrations. Formaldehyde concentration was above 50 ppbv during night. There exists an apparent correlation between the variation of ground-level ozone concentration and photochemical reactions. The results indicate that in addition to benzene and toluene, ozone is a deleterious pollutant. The commercial DOAS system provides reliable information on distribution patterns of major air pollutants depending on their concentration levels in ambient air.

  9. Heat exchanger bypass system for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

  10. NHEXAS PHASE I REGION 5 STUDY--STANDARD OPERATING PROCEDURE FOR THE CALIBRATION OF PERKIN ELMER (PE) MODEL 5100 ZL ATOMIC ABSORPTION SPECTROMETER: GRAPHITE FURNACE (NHX/SOP-171-005)

    EPA Science Inventory

    This procedure describes the calibration procedures and performance checks required to ensure the consistent performance of the Perkin Elmer (PE) Model 5100 zl atomic absorption spectrometer with graphite furnace unit as a whole. Separate calibration procedures were not required ...

  11. The K1.8BR spectrometer system at J-PARC

    NASA Astrophysics Data System (ADS)

    Agari, Keizo; Ajimura, Shuhei; Beer, George; Bhang, Hyoungchan; Bragadireanu, Mario; Buehler, Paul; Busso, Luigi; Cargnelli, Michael; Choi, Seonho; Curceanu, Catalina; Enomoto, Shun; Faso, Diego; Fujioka, Hiroyuki; Fujiwara, Yuya; Fukuda, Tomokazu; Guaraldo, Carlo; Hashimoto, Tadashi; Hayano, Ryugo S.; Hiraiwa, Toshihiko; Hirose, Erina; Ieiri, Masaharu; Iio, Masami; Iliescu, Mihai; Inoue, Kentaro; Ishiguro, Yosuke; Ishikawa, Takashi; Ishimoto, Shigeru; Ishiwatari, Tomoichi; Itahashi, Kenta; Iwai, Masaaki; Iwasaki, Masahiko; Kakiguchi, Yutaka; Katoh, Yohji; Kawasaki, Shingo; Kienle, Paul; Kou, Hiroshi; Ma, Yue; Marton, Johann; Matsuda, Yasuyuki; Minakawa, Michifumi; Mizoi, Yutaka; Morra, Ombretta; Muto, Ryotaro; Nagae, Tomofumi; Naruki, Megumi; Noumi, Hiroyuki; Ohnishi, Hiroaki; Okada, Shinji; Outa, Haruhiko; Piscicchia, Kristian; Lener, Marco Poli; Vidal, Antonio Romero; Sada, Yuta; Sakaguchi, Atsushi; Sakuma, Fuminori; Sato, Masaharu; Sato, Yoshinori; Sawada, Shin'ya; Scordo, Alessandro; Sekimoto, Michiko; Shi, Hexi; Shirakabe, Yoshihisa; Sirghi, Diana; Sirghi, Florin; Suzuki, Ken; Suzuki, Shoji; Suzuki, Takatoshi; Suzuki, Yoshihiro; Takahashi, Hitoshi; Tanaka, Kazuhiro; Tanaka, Nobuaki; Tatsuno, Hideyuki; Tokuda, Makoto; Tomono, Dai; Toyoda, Akihisa; Tsukada, Kyo; Doce, Oton Vazquez; Watanabe, Hiroaki; Widmann, Eberhard; Wünschek, Barbara K.; Yamanoi, Yutaka; Yamazaki, Toshimitsu; Yim, Heejoong; Zmeskal, Johann

    2012-11-01

    A new spectrometer system has been designed and constructed at the secondary beam line K1.8BR in the hadron hall of J-PARC to investigate bar {K} N interactions and bar {K}-nuclear bound systems. The spectrometer consists of a high precision beam line spectrometer, a liquid 3He/4He/D2 target system, a cylindrical detector system that surrounds the target to detect the decay particles from the target region, and a neutron time-of-flight counter array located ˜15 m downstream of the target position. Details of the design, construction, and performance of the detector components are described.

  12. Cloud Absorption Radiometer Autonomous Navigation System - CANS

    NASA Technical Reports Server (NTRS)

    Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

    2013-01-01

    CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode

  13. Light weight airborne imaging spectrometer remote sensing system for mineral exploration in China

    NASA Astrophysics Data System (ADS)

    Wu, Taixia; Zhang, Lifu; Cen, Yi; Wang, Jinnian; Tong, Qingxi

    2014-05-01

    Imaging spectrometers provide the unique combination of both spatially contiguous spectra and spectrally contiguous images of the Earth's surface that allows spatial mapping of these minerals. One of the successful applications of imaging spectrometers remote sensing identified was geological mapping and mineral exploration. A Light weight Airborne Imaging Spectrometer System (LAISS) has been developed in China. The hardware of the compact LAISS include a VNIR imaging spectrometer, a SWIR imaging spectrometer, a high resolution camera and a position and attitude device. The weight of the system is less than 20kg. The VNIR imaging spectrometer measures incoming radiation in 344 contiguous spectral channels in the 400-1000 nm wavelength range with spectral resolution of better than 5 nm and creates images of 464 pixels for a line of targets with a nominal instantaneous field of view (IFOV) of ~1 mrad. The SWIR imaging spectrometer measures incoming radiation in the 1000-2500 nm wavelength range with spectral resolution of better than 10 nm with a nominal instantaneous field of view (IFOV) of ~2 mrad. The 400 to 2500nm spectral range provides abundant information about many important Earth-surface minerals. A ground mineral scan experiment and an UAV carried flying experiment has been done. The experiment results show the LAISS have achieved relative high performance levels in terms of signal to noise ratio and image quality. The potential applications for light weight airborne imaging spectrometer system in mineral exploration are tremendous.

  14. Acoustic-optic spectrometer. 1: Noise contributions and system consideration

    NASA Technical Reports Server (NTRS)

    Chin, G.

    1984-01-01

    An acousto-optic spectrometer (AOS) used as an IF spectrometer to a heterodyne receiver is modeled as a total power multi-channel integrating receiver. Systematic noise contributions common to all total power, time integrating receivers, as well as noise terms unique to the use of optical elements and photo-detectors in an AOS are identified and discussed. In addition, degradation of signal-to-noise ratio of an unbalanced Dicke receiver compared to a balanced Dicke receiver is found to be due to gain calibration processing and is not an instrumental effect.

  15. JPL Fourier transform ultraviolet spectrometer

    NASA Technical Reports Server (NTRS)

    Cageao, R. P.; Friedl, R. R.; Sander, Stanley P.; Yung, Y. L.

    1994-01-01

    The Fourier Transform Ultraviolet Spectrometer (FTUVS) is a new high resolution interferometric spectrometer for multiple-species detection in the UV, visible and near-IR. As an OH sensor, measurements can be carried out by remote sensing (limb emission and column absorption), or in-situ sensing (long-path absorption or laser-induced fluorescence). As a high resolution detector in a high repetition rate (greater than 10 kHz) LIF system, OH fluorescence can be discriminated against non-resonant background emission and laser scatter, permitting (0, 0) excitation.

  16. Design for Manufacturing for Energy Absorption Systems

    SciTech Connect

    Del Prete, A.; Primo, T.; Papadia, G.; Manisi, B.

    2011-05-04

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  17. Design for Manufacturing for Energy Absorption Systems

    NASA Astrophysics Data System (ADS)

    Del Prete, A.; Primo, T.; Papadia, G.; Manisi, B.

    2011-05-01

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  18. Self-adjusting control system of the electrodynamic velocity transducer for Mössbauer spectrometer

    NASA Astrophysics Data System (ADS)

    Zekhtser, M. Yu.; Revyakin, A. S.; Sarychev, D. A.

    2016-08-01

    The novel control system has been developed on the basis of motion equation for the moving part of the electrodynamic velocity transducer of Mössbauer spectrometer. The motion equation coefficients are the parameters of its vibrating system. The square of cyclic eigenfrequency and damping factor are automatically determined by the control software for the spectrometer using the express analysis of free damped oscillations before any measurements are taken. The control system does not require manual adjustment of the spectrometer before the experiment. It exhibits accuracy of self-tuning and high degree of Doppler modulation stability in long-term experiments, providing high quality Mössbauer spectra.

  19. A compact tunable diode laser absorption spectrometer to monitor CO2 at 2.7 μm wavelength in hypersonic flows.

    PubMed

    Vallon, Raphäel; Soutadé, Jacques; Vérant, Jean-Luc; Meyers, Jason; Paris, Sébastien; Mohamed, Ajmal

    2010-01-01

    Since the beginning of the Mars planet exploration, the characterization of carbon dioxide hypersonic flows to simulate a spaceship's Mars atmosphere entry conditions has been an important issue. We have developed a Tunable Diode Laser Absorption Spectrometer with a new room-temperature operating antimony-based distributed feedback laser (DFB) diode laser to characterize the velocity, the temperature and the density of such flows. This instrument has been tested during two measurement campaigns in a free piston tunnel cold hypersonic facility and in a high enthalpy arc jet wind tunnel. These tests also demonstrate the feasibility of mid-infrared fiber optics coupling of the spectrometer to a wind tunnel for integrated or local flow characterization with an optical probe placed in the flow. PMID:22219703

  20. A Compact Tunable Diode Laser Absorption Spectrometer to Monitor CO2 at 2.7 μm Wavelength in Hypersonic Flows

    PubMed Central

    Vallon, Raphäel; Soutadé, Jacques; Vérant, Jean-Luc; Meyers, Jason; Paris, Sébastien; Mohamed, Ajmal

    2010-01-01

    Since the beginning of the Mars planet exploration, the characterization of carbon dioxide hypersonic flows to simulate a spaceship’s Mars atmosphere entry conditions has been an important issue. We have developed a Tunable Diode Laser Absorption Spectrometer with a new room-temperature operating antimony-based distributed feedback laser (DFB) diode laser to characterize the velocity, the temperature and the density of such flows. This instrument has been tested during two measurement campaigns in a free piston tunnel cold hypersonic facility and in a high enthalpy arc jet wind tunnel. These tests also demonstrate the feasibility of mid-infrared fiber optics coupling of the spectrometer to a wind tunnel for integrated or local flow characterization with an optical probe placed in the flow. PMID:22219703

  1. Time-resolved near-edge x-ray absorption fine structure spectroscopy on photo-induced phase transitions using a tabletop soft-x-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Grossmann, P.; Rajkovic, I.; Moré, R.; Norpoth, J.; Techert, S.; Jooss, C.; Mann, Klaus

    2012-05-01

    We present a table-top soft-x-ray spectrometer for the wavelength range λ = 1-5 nm based on a stable laser-driven x-ray source, making use of a gas-puff target. With this setup, optical light-pump/soft-x-ray probe near-edge x-ray absorption fine structure (NEXAFS) experiments with a temporal resolution of about 230 ps are feasible. Pump-probe NEXAFS measurements were carried out in the "water-window" region (2.28 nm-4.36 nm) on the manganite Pr0.7Ca0.3MnO3, investigating diminutive changes of the oxygen K edge that derive from an optically induced phase transition. The results show the practicability of the table-top soft-x-ray spectrometer on demanding investigations so far exclusively conducted at synchrotron radiation sources.

  2. Nanofibrous membrane-based absorption refrigeration system

    SciTech Connect

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  3. A study of aerosol optical properties using a lightweight optical particle spectrometer and sun photometer from an unmanned aerial system

    NASA Astrophysics Data System (ADS)

    Telg, H.; Murphy, D. M.; Bates, T. S.; Johnson, J. E.; Gao, R. S.

    2015-12-01

    A miniaturized printed optical particle spectrometer (POPS) and sun photometer (miniSASP) have been developed recently for unmanned aerial systems (UAS) and balloon applications. Here we present the first scientific data recorded by the POPS and miniSASP from a Manta UAS during a field campaign on Svalbard, Norway, in April 2015. As part of a payload composed of five different aerosol instruments (absorption photometer, condensation particle counter, filter sampler, miniSASP and POPS) we collected particle size distributions, the optical depth (OD) and the sky brightness from 0 to 3000 m altitude. The complementary measurement approaches of the miniSASP and POPS allow us to calculate aerosol optical properties such as the aerosol optical depth and the angstrom exponent or the asymmetry parameter independently. We discuss deviation between results with respect to aerosol properties, e.g. hygroscopicity and absorption, as well as instrumental limitations.

  4. Correlation spectrometer

    DOEpatents

    Sinclair, Michael B.; Pfeifer, Kent B.; Flemming, Jeb H.; Jones, Gary D.; Tigges, Chris P.

    2010-04-13

    A correlation spectrometer can detect a large number of gaseous compounds, or chemical species, with a species-specific mask wheel. In this mode, the spectrometer is optimized for the direct measurement of individual target compounds. Additionally, the spectrometer can measure the transmission spectrum from a given sample of gas. In this mode, infrared light is passed through a gas sample and the infrared transmission signature of the gasses present is recorded and measured using Hadamard encoding techniques. The spectrometer can detect the transmission or emission spectra in any system where multiple species are present in a generally known volume.

  5. Development and metrological characterization of a tunable diode laser absorption spectroscopy (TDLAS) spectrometer for simultaneous absolute measurement of carbon dioxide and water vapor.

    PubMed

    Pogány, Andrea; Wagner, Steven; Werhahn, Olav; Ebert, Volker

    2015-01-01

    Simultaneous detection of two analytes, carbon dioxide (CO2) and water vapor (H2O), has been realized using tunable diode laser absorption spectroscopy (TDLAS) with a single distributed feedback diode laser at 2.7 μm. The dynamic range of the spectrometer is extended from the low parts per million to the percentage range using two gas cells, a single-pass cell with 0.77 m, and a Herriott-type multipass cell with 76 m path length. Absolute measurements were carried out, i.e., amount fractions of the analytes were calculated based on previously determined spectral line parameters, without the need for an instrument calibration using gas standards. A thorough metrological characterization of the spectrometer is presented. We discuss traceability of all parameters used for amount fraction determination and provide a comprehensive uncertainty assessment. Relative expanded uncertainties (k = 2, 95% confidence level) of the measured amount fractions are shown to be in the 2-3% range for both analytes. Minimum detectable amount fractions are 0.16 μmol/mol for CO2 and 1.1 μmol/mol for H2O for 76 m path length and 5 s averaging time. This corresponds to normalized detection limits of 27 μmol/mol m Hz(-1/2) for CO2 and 221 μmol/mol m Hz(-1/2) for H2O. Precision of the spectrometer, determined using Allan variance analysis, is 3.3 nmol/mol for CO2 and 21 nmol/mol for H2O. The spectrometer has been validated using reference gas mixtures with known CO2 and H2O amount fractions. An application example of the absolute TDLAS spectrometer as a reference instrument to validate other sensors is also presented. PMID:25658222

  6. REMOTE SENSING OF OZONE USING AN INFRARED DIFFERENTIAL ABSORPTION SYSTEM

    EPA Science Inventory

    A prototype airborne downlooking infrared differential absorption system using CO2 TEA (transverse excited atmospheric) lasers is described. The system uses two wavelengths and topographic reflection to measure the integrated column concentration of ozone between the laser source...

  7. A quantum cascade laser absorption spectrometer devoted to the in situ measurement of atmospheric N2O and CH4 emission fluxes

    NASA Astrophysics Data System (ADS)

    Mappé, I.; Joly, L.; Durry, G.; Thomas, X.; Decarpenterie, T.; Cousin, J.; Dumelie, N.; Roth, E.; Chakir, A.; Grillon, P. G.

    2013-02-01

    This paper describes a Quantum Cascade Laser Absorption Spectrometer, called "QCLAS" that was developed to monitor in situ greenhouse gases like N2O and CH4, at high temporal resolution and with a high accuracy. The design of the laser sensor is reported as well as its performances in terms of precision error and field deployment capabilities. Finally, to demonstrate the efficiency and the robustness of QCLAS and its suitability for gas emission monitoring and for the determination of fluxes, we report the results from a field campaign, that took place in the Wallis and Futuna Islands in 2011, to investigate the impact of environmental intensive pig farming.

  8. A Microfluidics-HPLC/Differential Mobility Spectrometer Macromolecular Detection System for Human and Robotic Missions

    NASA Technical Reports Server (NTRS)

    Coy, S. L.; Killeen, K.; Han, J.; Eiceman, G. A.; Kanik, I.; Kidd, R. D.

    2011-01-01

    Our goal is to develop a unique, miniaturized, solute analyzer based on microfluidics technology. The analyzer consists of an integrated microfluidics High Performance Liquid Chromatographic chip / Differential Mobility Spectrometer (?HPLCchip/ DMS) detection system

  9. A microelectromechanical systems-enabled, miniature triple quadrupole mass spectrometer.

    PubMed

    Wright, Steven; Malcolm, Andrew; Wright, Christopher; O'Prey, Shane; Crichton, Edward; Dash, Neil; Moseley, Richard W; Zaczek, Wojciech; Edwards, Peter; Fussell, Richard J; Syms, Richard R A

    2015-03-17

    Miniaturized mass spectrometers are becoming increasingly capable, enabling the development of many novel field and laboratory applications. However, to date, triple quadrupole tandem mass spectrometers, the workhorses of quantitative analysis, have not been significantly reduced in size. Here, the basis of a field-deployable triple quadrupole is described. The key development is a highly miniaturized ion optical assembly in which a sequence of six microengineered components is employed to generate ions at atmospheric pressure, provide a vacuum interface, effect ion guiding, and perform fragmentation and mass analysis. Despite its small dimensions, the collision cell efficiently fragments precursor ions and yields product ion spectra that are very similar to those recorded using conventional instruments. The miniature triple quadrupole has been used to detect thiabendazole, a common pesticide, in apples at a level of 10 ng/g. PMID:25708099

  10. Column Path Length Measurements Using a Multi-Frequency, Intensity-Modulated Continuous-Wave (IM-CW) Laser Absorption Spectrometer

    NASA Astrophysics Data System (ADS)

    Harrison, F. W.; Lin, B.; Browell, E. V.; Dobler, J.; McGregor, D.; Kooi, S. A.; Collins, J. E.

    2012-12-01

    Accurate understanding of carbon balance in the environment is critical to projections of the future evolution of the Earth's climate. As a result, the NRC Decadal Survey (DS) of Earth Science and Applications from Space identified Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) as a mid-term (Tier II) mission. The active space remote measurement of the column CO2 mixing ratio (XCO2) for the ASCENDS mission requires the simultaneous measurement of the CO2 and O2 number density and the column path length over which they are measured in order to derive the average XCO2 column. This paper presents methods for measuring the path lengths of the CO2 and O2 measurements that are inherent to the Multi-Functional Fiber Laser Lidar (MFLL), a laser absorption spectrometer (LAS) system under development for the ASCENDS mission. The MFLL is a multi-frequency intensity-modulated continuous-wave (IM-CW) LAS operating near 1.57 and 1.26 μm that uses a range-encoded modulation technique to minimize bias from thin clouds in the CO2 and O2 column measurements while simultaneously measuring the path length to the surface and to intervening cloud layers. This paper discusses the latest MFLL ground and flight test results. During these tests, range-encoded modulation techniques were demonstrated for path length measurements and the MFLL remote CO2 column measurements were evaluated against in situ CO2 measurements. This paper describes the encoding techniques employed, presents an approach for obtaining column path length measurements during CO2 retrievals, and presents the accuracy and precision of the technique. Measurement of path length meeting ASCENDS requirements of approximately 2-m precision were obtained in ground testing and demonstrated during flights over Railroad Valley, NV.

  11. Direct determination of total sulfur in wine using a continuum-source atomic-absorption spectrometer and an air-acetylene flame.

    PubMed

    Huang, Mao Dong; Becker-Ross, Helmut; Florek, Stefan; Heitmann, Uwe; Okruss, Michael

    2005-08-01

    Determination of sulfur in wine is an important analytical task, particularly with regard to food safety legislation, wine trade, and oenology. Hitherto existing methods for sulfur determination all have specific drawbacks, for example high cost and time consumption, poor precision or selectivity, or matrix effects. In this paper a new method, with low running costs, is introduced for direct, reliable, rapid, and accurate determination of the total sulfur content of wine samples. The method is based on measurement of the molecular absorption of carbon monosulfide (CS) in an ordinary air-acetylene flame by using a high-resolution continuum-source atomic-absorption spectrometer including a novel high-intensity short-arc xenon lamp. First results for total sulfur concentrations in different wine samples were compared with data from comparative ICP-MS measurements. Very good agreement within a few percent was obtained. PMID:15999269

  12. Fieldable Fourier Transform Spectrometer: System Construction, Background Variability Measurements, and Chemical Attack Warning Experiments

    SciTech Connect

    Hatchell, Brian K.; Harper, Warren W.; Batishko, Charles R.; Johnson, Timothy J.; Sheen, David M.; Stewart, Timothy L.; Schultz, John F.

    2002-10-01

    The infrared sensors task at the Pacific Northwest National Laboratory (PNNL) is focused on the science and technology of remote and in-situ chemical sensors for detecting proliferation and countering terrorism. Missions to be addressed by remote chemical sensor development will include detecting proliferation of nuclear or chemical weapons, and providing warning of terrorist use of chemical weapons. Missions to be addressed by in-situ chemical sensor development include countering terrorism by screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons, or chemical weapons residues, and mapping contaminated areas. The science and technology relevant to these primary missions is also likely to be useful for battlefield chemical weapons defense, air operations support, monitoring emissions from chemical weapons destruction facilities or industrial chemical plants, and law enforcement applications. PNNL will seek to serve organizations with direct interest in these missions through collaborative research and development efforts approved by NA-22. During FY02, PNNL began assembling a remote IR detection capability that would allow field experiments to be conducted. The capability consists of a commercially available FTIR (Fourier Transform Infrared) emission spectrometer and a frequency-modulation differential-absorption LIDAR (FM-DIAL) system being developed at PNNL. To provide environmental protection for these systems, a large, well insulated, temperature controlled trailer was specified and procured. While the FTIR system was field-ready, the FM-DIAL system required many modifications to prepare for field deployment. This document provides an overview of the FTIR system, summarizes the modifications made to the FM-DIAL system, and describes the salient features of the remote systems trailer.

  13. Atmospheric solar absorption measurements in the 9-11 micron region using a diode laser heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Harward, C. N.; Hoell, J. M., Jr.

    1980-01-01

    A tunable diode laser heterodyne radiometer was developed for ground based measurements of atmospheric solar absorption spectra in the 9 to 12 micron spectral range. The performance and operating characteristics of this tunable infrared heterodyne radiometer (TIHR) is discussed along with recently measured heterodyne solar absorption spectra in the 10 to 11 micron spectral region.

  14. Optical system design of the Dyson imaging spectrometer based on the Fery prism

    NASA Astrophysics Data System (ADS)

    Pei, Linlin; Xiangli, Bin; Lv, Qunbo; Shao, Xiaopeng

    2016-08-01

    Imaging spectrometer has obtained wide development since rich feature information can be obtained by it; now, we focus on its high spectral resolution and miniaturization. In this paper, we design the Dyson imaging spectrometer system based on Fery prism. The average spectral resolution is 4.3 nm and the structure of the total length is 229 mm. It is a small, high-spectrometer imaging system. The front and rear surface of the traditional prism are plane, but the surfaces of the Fery prism are spherical, which can provide some optical power to realize imaging function and produce the dispersion effect. The Fery prism does not need to be placed in the parallel optical path, which simplifies the collimator lens and the imaging lens and are necessary in the prism spectrometer, making it possible to obtain a compact spectrometer. Full-spectrum transmittance of the prism is up to 94 %. Compared to the convex grating, the energy efficiency is greatly improved, and the free spectral range is wider, and its dispersion will not bring higher-order spectral aliasing problem. The small high spectrometer only includes two components. Its spectral range is from 400 to 1000 nm, covering the near-ultraviolet to near-infrared. The various aberrations of the typical spectrum are corrected. The spectrometer is excellent in performance.

  15. Optical system design of the Dyson imaging spectrometer based on the Fery prism

    NASA Astrophysics Data System (ADS)

    Pei, Linlin; Xiangli, Bin; Lv, Qunbo; Shao, Xiaopeng

    2016-07-01

    Imaging spectrometer has obtained wide development since rich feature information can be obtained by it; now, we focus on its high spectral resolution and miniaturization. In this paper, we design the Dyson imaging spectrometer system based on Fery prism. The average spectral resolution is 4.3 nm and the structure of the total length is 229 mm. It is a small, high-spectrometer imaging system. The front and rear surface of the traditional prism are plane, but the surfaces of the Fery prism are spherical, which can provide some optical power to realize imaging function and produce the dispersion effect. The Fery prism does not need to be placed in the parallel optical path, which simplifies the collimator lens and the imaging lens and are necessary in the prism spectrometer, making it possible to obtain a compact spectrometer. Full-spectrum transmittance of the prism is up to 94 %. Compared to the convex grating, the energy efficiency is greatly improved, and the free spectral range is wider, and its dispersion will not bring higher-order spectral aliasing problem. The small high spectrometer only includes two components. Its spectral range is from 400 to 1000 nm, covering the near-ultraviolet to near-infrared. The various aberrations of the typical spectrum are corrected. The spectrometer is excellent in performance.

  16. Fully automated spatially resolved reflectance spectrometer for the determination of the absorption and scattering in turbid media

    NASA Astrophysics Data System (ADS)

    Foschum, F.; Jäger, M.; Kienle, A.

    2011-10-01

    We describe a fully automated setup which is based on measurements of the spatially resolved reflectance for the determination of the reduced scattering and absorption coefficients in semi-infinite turbid media. The sample is illuminated with a xenon light source in combination with a monochromator enabling the scan of the wavelength from 450 nm to 950 nm. Reflected light from the sample is detected with a CCD camera providing a high spatial resolution. The essential steps for signal processing including, e.g., the consideration of the optical transfer function and the correct treatment of the background subtraction, are presented. The solutions of the diffusion theory and of the radiative transfer theory are investigated regarding the exact detection and illumination geometry. Systematic errors caused by using the different theories for fitting the optical parameters are characterized. The system was validated using liquid phantoms which contain Intralipid 20% and ink, and the measurement range of the system is specified. Further, we carefully characterized the optical properties of Intralipid 20% in the wavelength range between 450 nm and 950 nm.

  17. Improving Atmospheric Correction for Visible/Short Wave Infrared (VSWIR) Imaging Spectrometers with Iterative Fitting of Absorption By Three Phases of Water

    NASA Astrophysics Data System (ADS)

    Pennington, E. A.; Thompson, D. R.; Green, R. O.; Gao, B. C.

    2014-12-01

    Airborne imaging spectrometers like the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) offer valuable insight into the Earth's terrestrial and ocean ecosystems, mineralogy, and land use. Estimating surface reflectance requires accounting for atmospheric absorption, which is sensitive to the local abundance of water vapor. Analysts typically estimate water vapor concentrations using the depths of absorption features, which can be inaccurate by up to 50% over surface features containing liquid water or ice. This can bias the retrieved water vapor maps and create atmospheric artifacts in reflectance spectra. A new retrieval method offers significant accuracy improvements over plant canopies or ice by estimating the path lengths of all three phases of water simultaneously, adjusting absorptions to best fit the measurement over a broader spectral interval. This paper assesses the remaining sources of error for the three-phase retrieval technique. We analyze retrievals for synthetic data when the 940 and 1140 nm wavelength features are fitted, for initial vapor path estimates ranging from 0 to ±50% accuracy. These tests indicate that most error comes from inaccuracy in the initial path estimate used to obtain vapor absorption coefficients. We evaluate a modified algorithm that uses multiple iterations to refine this estimate. Error is found to approach a constant value, demonstrating improved robustness to initialization conditions. We also assess the new iterative method using corrected AVIRIS data over various environments. The iterative method yields significantly better water vapor maps, reducing spurious correlations between vegetation canopy water and vapor estimates. The new iterative method offers accuracy improvements over traditional Visible/Short Wave Infrared (VSWIR) atmospheric correction methods, at modest computational cost.

  18. Design of optical system for spectrometer involving a volume phase holographic transmission grating

    NASA Astrophysics Data System (ADS)

    Ren, Zhong; Liu, Guodong; Huang, Zhen

    2014-08-01

    At present, spectrometer has popularly being used into varieties of fields including environment, food, medical health monitoring and metal industry because it has the advantages of noninvasive, high efficient and convenient etc. The performance of the spectrometer is determined by its optical system. Normally, according to the apparatus and principle of splitting-light, optical system of spectrometer can be classified into several categories, for example, filter-typed, dispersion typed, Fourier transform typed and acousto-optic tunable typed. The grating typed optical system has been popularly used into the spectrometer due to the features of higher diffraction efficiency, resolution and dispersion rate etc. In the grating-typed optical system, although the traditional plane and concave grating have usually been used into some spectrometers, some disadvantages of them still limit their applications, such as, large aberration, worse spectral flatness and low deficiency, etc. In this paper, to overcome these disadvantages of the traditional plane and concave grating, a novel optical system for spectrometer (OSS) based on volume phase holographic transmission (VPHT) grating was designed. For this novel grating, its manufacture and theories were investigated, and its diffraction efficiency was firstly numerically simulated according to different parameters. In order to prove the feasibility of this designed OSS, the spectral calibration experiment was performed and the spectral resolution reached 2nm.

  19. The low-ion QSO absorption-line systems

    SciTech Connect

    Lanzetta, K.M.

    1988-01-01

    Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Ly{alpha} absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Ly{alpha} absorber toward Q1337 + 113 are presented.

  20. [The alignment of the optical system for 216 coude focus echelle spectrometer].

    PubMed

    Zhu, Y; Pan, J

    1997-04-01

    This paper gives a brief introduction about the structure of the echelle spectrometer which was installed at coude focus of the chinese 2. 16 meter astronomical telescope. According to the design requirment of this echelle spectrometer, the main points and steps of alignment of optical system are analysed. Authors work out a practical alignment scheme in which the fewest auxiliary tools are used. PMID:15810402

  1. Atmospheric solar absorption measurements in the 9 to 11 mu m region using a diode laser heterodyne spectrometer

    NASA Technical Reports Server (NTRS)

    Harward, C. N.; Hoell, J. M., Jr.

    1980-01-01

    A tunable diode laser heterodyne radiometer was developed for ground-based measurements of atmospheric solar absorption spectra in the 8 to 12 microns spectral range. The performance and operating characteristics of this Tunable Infrared Heterodyne Radiometer (TIHR) are discussed along with atmospheric solar absorption spectra of HNO3, O3, CO2, and H2O in the 9 to 11 microns spectral region.

  2. 25. View down launch tube, showing shock absorption system. Lyon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. View down launch tube, showing shock absorption system. Lyon - Whiteman Air Force Base, Minuteman Missile Launch Facility Trainer T-12, Northeast of Oscar-01 Missile Alert Facility, Knob Noster, Johnson County, MO

  3. Comparison of COSPEC and two miniature ultraviolet spectrometer systems for SO2 measurements using scattered sunlight

    USGS Publications Warehouse

    Elias, Tamar; Sutton, A. Jeff; Oppenheimer, Clive; Horton, Keith A.; Garbeil, Harold; Tsanev, Vitchko; McGonigle, Andrew J.S.; Williams-Jones, Glyn

    2006-01-01

    The correlation spectrometer (COSPEC), the principal tool for remote measurements of volcanic SO2, is rapidly being replaced by low-cost, miniature, ultraviolet (UV) spectrometers. We compared two of these new systems with a COSPEC by measuring SO2 column amounts at Kīlauea Volcano, Hawaii. The two systems, one calibrated using in-situ SO2 cells, and the other using a calibrated laboratory reference spectrum, employ similar spectrometer hardware, but different foreoptics and spectral retrieval algorithms. Accuracy, signal-to-noise, retrieval parameters, and precision were investigated for the two configurations of new miniature spectrometer. Measurements included traverses beneath the plumes from the summit and east rift zone of Kīlauea, and testing with calibration cells of known SO2 concentration. The results obtained from the different methods were consistent with each other, with <8% difference in estimated SO2 column amounts up to 800 ppm m. A further comparison between the COSPEC and one of the miniature spectrometer configurations, the ‘FLYSPEC’, spans an eight month period and showed agreement of measured emission rates to within 10% for SO2 column amounts up to 1,600 ppm m. The topic of measuring high SO2 burdens accurately is addressed for the Kīlauea measurements. In comparing the foreoptics, retrieval methods, and resultant implications for data quality, we aim to consolidate the various experiences to date, and improve the application and development of miniature spectrometer systems.`

  4. Beam shaping system based on a prism array for improving the throughput of a dispersive spectrometer.

    PubMed

    Shi, Zhendong; Fang, Liang; Fan, Bin; Zhou, Chongxi

    2015-04-01

    A beam shaping system (BSS) for improving the throughput of a dispersive spectrometer is presented by employing two anamorphic lenses and a prism array to segment the beam. The BSS was designed based on the inverse method of beam shaping for laser diode bars and the means of an optical slicer. In an experiment, a BSS was set up so that the incident light of a neon lamp with a circular spot from an input fiber was transformed into an elliptical spot coupled into a slit of a spectrometer without a change of divergence. Spectral measurement results demonstrate that the throughput of the dispersive spectrometer was doubled without loss of spectral resolution. The BSS can be combined with the existing dispersive spectrometer to improve the luminous flux and signal-to-noise ratio. PMID:25967181

  5. Magnet coil system for a superconducting spectrometer (HISS)

    SciTech Connect

    Reimers, R.M.; Wolgast, R.C.; Yamamoto, R.M.

    1983-03-01

    The Heavy Ion Superconducting Spectrometer (HISS) facility and coils are briefly described while most of the paper discusses the support structures consisting of flanged doubly tapered stainless steel cylinders having a Z-shaped cross-section with average diameter of approximately 2.35 meters and height of approx. .49 meters. This member serves as a one piece coil support to resist gravitational, seismic, and magnetic forces with an approximate heat leak to helium of 59 watts per cylinder during operation of magnet at 4 degrees K. Maximum magnetic forces on each coil are over 11 meganewtons at 3T excitation. Magnetic forces attracting the coils to the core vary with excitation in direction as well as in magnitude. Radial magnetic forces produce stresses internal to the coil bobbin.

  6. Electromagnetically induced absorption in a three-resonator metasurface system

    PubMed Central

    Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S.; Zhang, Weili

    2015-01-01

    Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely explored. Here we present the observation of the EIA analog due to constructive interference in a vertically coupled three-resonator metamaterial system that consists of two bright and one dark resonator. The absorption resonance is one of the collective modes of the tripartite unit cell. Theoretical analysis shows that the absorption arises from a magnetic resonance induced by the near-field coupling of the three resonators within the unit cell. A classical analog of EIA opens up opportunities for designing novel photonic devices for narrow-band filtering, absorptive switching, optical modulation, and absorber applications. PMID:26023061

  7. Electromagnetically induced absorption in a three-resonator metasurface system.

    PubMed

    Zhang, Xueqian; Xu, Ningning; Qu, Kenan; Tian, Zhen; Singh, Ranjan; Han, Jiaguang; Agarwal, Girish S; Zhang, Weili

    2015-01-01

    Mimicking the quantum phenomena in metamaterials through coupled classical resonators has attracted enormous interest. Metamaterial analogs of electromagnetically induced transparency (EIT) enable promising applications in telecommunications, light storage, slow light and sensing. Although the EIT effect has been studied extensively in coupled metamaterial systems, excitation of electromagnetically induced absorption (EIA) through near-field coupling in these systems has only been sparsely explored. Here we present the observation of the EIA analog due to constructive interference in a vertically coupled three-resonator metamaterial system that consists of two bright and one dark resonator. The absorption resonance is one of the collective modes of the tripartite unit cell. Theoretical analysis shows that the absorption arises from a magnetic resonance induced by the near-field coupling of the three resonators within the unit cell. A classical analog of EIA opens up opportunities for designing novel photonic devices for narrow-band filtering, absorptive switching, optical modulation, and absorber applications. PMID:26023061

  8. Christiansen effect in disperse systems with resonant absorption

    SciTech Connect

    Zimnyakov, D A; Isaeva, Elmira A; Isaeva, A A

    2012-01-31

    We discuss the results of experimental studies of competition of absorption and scattering of laser radiation propagating in dispersive media with resonant absorption. As media under study, use is made of a suspension of polystyrene particles in solutions of rhodamine 6G in ethylene glycol probed by laser light with a wavelength of 532 nm. It is found that an increase in the dye concentration leads to an increase in optical transmittance of suspensions and an increase in speckle modulation of the forward-scattered radiation. We interpret these features as a manifestation of Christiansen effect in disperse systems with resonance absorption.

  9. New generation of data acquisition and data storage systems of the IBR-2 reactor spectrometers complex

    NASA Astrophysics Data System (ADS)

    Kulikov, S. A.; Prikhodko, V. I.

    2016-07-01

    The paper presents an overview of works on the creation of data acquisition and data storage systems, which have been carried out in the Department of the IBR-2 spectrometers complex (DCS) of the Frank Laboratory of Neutron Physics (FLNP) over the past 15 years (before, during, and after the modernization of the IBR-2 reactor). These systems represent a unified set of identical (from the viewpoint of hardware) modules limited in type but functionally complete, wherein distinctions in parameters, functional capabilities, encoding, correction and preliminary data processing procedures specific to each spectrometer are realized on the level of microprograms, electronic tables, and integrated software control system.

  10. Evaluations of the commercial spectrometer systems for safeguards applications using the germanium detectors

    SciTech Connect

    Vo, D.T.

    1998-12-31

    Safeguards applications require the best spectrometer systems with excellent resolution, stability, and throughput. Instruments must perform well in all the situations and environments. Data communication to the computer should be convenient, fast, and reliable. The software should have all the necessary tools and be ease to use. Portable systems should be small in size, lightweight, and have a long battery life. Nine commercially available spectrometer systems are tested with both the planar and coaxial germanium detectors. Considering the performance of the Digital Signal Processors (DSP), digital-based spectroscopy may be the future of gamma-ray spectroscopy.

  11. Development of a Near-Ir Cavity Enhanced Absorption Spectrometer for the Detection of Atmospheric Oxidation Products and Organoamines

    NASA Astrophysics Data System (ADS)

    Eddingsaas, Nathan C.; Jewell, Breanna; Thurnherr, Emily

    2014-06-01

    An estimated 10,000 to 100,000 different compounds have been measured in the atmosphere, each one undergoes many oxidation reactions that may or may not degrade air quality. To date, the fate of even some of the most abundant hydrocarbons in the atmosphere is poorly understood. One difficulty is the detection of atmospheric oxidation products that are very labile and decompose during analysis. To study labile species under atmospheric conditions, a highly sensitive, non-destructive technique is needed. Here we describe a near-IR incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) setup that we are developing to meet this end. We have chosen to utilize the near-IR, where vibrational overtone absorptions are observed, due to the clean spectral windows and better spectral separation of absorption features. In one spectral window we can simultaneously and continuously monitor the composition of alcohols, hydroperoxides, and carboxylic acids in an air mass. In addition, we have used our CEAS setup to detect organoamines. The long effective path length of CEAS allows for low detection limits, even of the overtone absorption features, at ppb and ppt levels.

  12. The Spectral Image Processing System (SIPS) - Interactive visualization and analysis of imaging spectrometer data

    NASA Technical Reports Server (NTRS)

    Kruse, F. A.; Lefkoff, A. B.; Boardman, J. W.; Heidebrecht, K. B.; Shapiro, A. T.; Barloon, P. J.; Goetz, A. F. H.

    1993-01-01

    The Center for the Study of Earth from Space (CSES) at the University of Colorado, Boulder, has developed a prototype interactive software system called the Spectral Image Processing System (SIPS) using IDL (the Interactive Data Language) on UNIX-based workstations. SIPS is designed to take advantage of the combination of high spectral resolution and spatial data presentation unique to imaging spectrometers. It streamlines analysis of these data by allowing scientists to rapidly interact with entire datasets. SIPS provides visualization tools for rapid exploratory analysis and numerical tools for quantitative modeling. The user interface is X-Windows-based, user friendly, and provides 'point and click' operation. SIPS is being used for multidisciplinary research concentrating on use of physically based analysis methods to enhance scientific results from imaging spectrometer data. The objective of this continuing effort is to develop operational techniques for quantitative analysis of imaging spectrometer data and to make them available to the scientific community prior to the launch of imaging spectrometer satellite systems such as the Earth Observing System (EOS) High Resolution Imaging Spectrometer (HIRIS).

  13. Installation of a variable-angle spectrometer system for monitoring diffuse and global solar radiation

    NASA Astrophysics Data System (ADS)

    Ormachea, O.; Abrahamse, A.; Tolavi, N.; Romero, F.; Urquidi, O.; Pearce, J. M.; Andrews, R.

    2013-11-01

    We report on the design and installation of a spectrometer system for monitoring solar radiation in Cochabamba, Bolivia. Both the light intensity and the spectral distribution affect the power produced by a photovoltaic device. Local variations in the solar spectrum (especially compared to the AM1.5 standard) may have important implications for device optimization and energy yield estimation. The spectrometer system, based on an Ocean Optics USB4000 (300-900nm) spectrometer, was designed to increase functionality. Typically systems only record the global horizontal radiation. Our system moves a fiber-optic cable 0-90 degrees and takes measurements in 9 degree increments. Additionally, a shadow band allows measurement of the diffuse component of the radiation at each position. The electronic controls utilize an Arduino UNO microcontroller to synchronizes the movement of two PAP bipolar (stepper) motors with the activation of the spectrometer via an external trigger. The spectrometer was factory calibrated for wavelength and calibrated for absolute irradiance using a Sellarnet SL1-Cal light source. We present preliminary results from data taken March-June, 2013, and comment on implications for PV devices in Cochabamba.

  14. Spectrophotometer-Integrating-Sphere System for Computing Solar Absorptance

    NASA Technical Reports Server (NTRS)

    Witte, William G., Jr.; Slemp, Wayne S.; Perry, John E., Jr.

    1991-01-01

    A commercially available ultraviolet, visible, near-infrared spectrophotometer was modified to utilize an 8-inch-diameter modified Edwards-type integrated sphere. Software was written so that the reflectance spectra could be used to obtain solar absorptance values of 1-inch-diameter specimens. A descriptions of the system, spectral reflectance, and software for calculation of solar absorptance from reflectance data are presented.

  15. A computer controlled mass spectrometer system for investigating the decomposition of non-metallic materials under atmospheric conditions

    NASA Technical Reports Server (NTRS)

    Thompson, J. M.

    1985-01-01

    A PDP 11/23 quadrupole mass spectrometer system was coupled to a nondiscriminating gas inlet system permitting gases at atmospheric pressure to be admitted into a high vacuum chamber containing the ion source of the mass spectrometer without separation of the gaseous components. The resolution of related software problems has resulted in a convenient computer-mass spectrometer system capable of generating masses, relative intensities and related data on the gaseous products resulting from the atmospheric thermal decomposition of nonmetallic materials.

  16. In situ ozone data for evaluation of the laser absorption spectrometer ozone remote sensor: 1979 southeastern Virginia urban plume study summer field program

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Mcdougal, D. S.; Mathis, J. J., Jr.

    1980-01-01

    Ozone data from the 1979 Southeastern Virginia Urban Study (SEV-UPS) field program are presented. The SEV-UPS was conducted for evaluation of an ozone remote sensor, the Laser Absorption Spectrometer. During the measurement program, remote-sensor evaluation was in two areas; (1) determination of the remote sensor's accuracy, repeatability, and operational characteristics, and (2) demonstration of the application of remotely sensed ozone data in air-quality studies. Data from six experiments designed to provide in situ ozone data for evaluation of the sensor in area 1, above, are presented. Experiments consisted of overflights of a test area with the remote sensor aircraft while in situ measurements with a second aircraft and selected surface stations provided correlative ozone data within the viewing area of the remote sensor.

  17. Airborne Tunable Laser Absorption Spectrometer (ATLAS) instrument characterization: Accuracy of the AASE (Airborne Arctic Stratospheric Expedition) and AAOE (Airborne Antarctic Ozone Experiment) nitrous oxide data sets

    SciTech Connect

    Loewenstein, M.; Podolske, J.R. ); Strahan, S.E. )

    1990-03-01

    ATLAS, the Airborne Tunable Laser Absorption Spectrometer, was used to measure nitrous oxide in the 1987 Airborne Antarctic Ozone Experiment (AAOE) and in the 1989 Airborne Arctic Stratospheric Expedition (AASE). After the AASE, a detailed study of the ATLAS characteristics was undertaken to quantify the error inherent in the in situ measurement of atmospheric N{sub 2}O. Using the latest calibration of the ATLAS (June 1989) and incorporating the recognized errors arising in the flight environment of ATLAS, the authors have established that for both the AASE and the AAOE most of the acquired N{sub 2}O data sets are accurate to {plus minus}10% (2 sigma). Data from two of the earlier AAOE flights had a larger uncertainty.

  18. Multiple γ Emission of the 137Xe 2849-2850 keV Levels Studied with the Modular Total Absorption Spectrometer (MTAS)

    NASA Astrophysics Data System (ADS)

    Rasco, B. C.; Fijałkowska, A.; Karny, M.; Rykaczewski, K. P.; Wolińska-Cichocka, M.; Goetz, K. C.; Grzywacz, R. K.; Gross, C. J.; Miernik, K.; Paulauskas, S. V.

    The Modular Total Absorption Spectrometer (MTAS) was constructed at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Lab to measure true β-decay feeding patterns in neutron rich nuclei. The first measurement campaign in early 2012 involved the measurement of over 20 different nuclei, many of which are "priority one" or "priority two" as assessed in the report by the OECD's Nuclear Energy Agency. We present first results from the measurement of γ-rays from the β decay of 137Xe with the new MTAS. In this contribution, we demonstrate the ability of MTAS to distinguish the γ decay paths from two levels very close in energy, but with very different de-excitation patterns in the daughter nucleus 137Cs.

  19. Gas chromatograph-mass spectrometer (GC/MS) system for quantitative analysis of reactive chemical compounds

    DOEpatents

    Grindstaff, Quirinus G.

    1992-01-01

    Described is a new gas chromatograph-mass spectrometer (GC/MS) system and method for quantitative analysis of reactive chemical compounds. All components of such a GC/MS system external to the oven of the gas chromatograph are programmably temperature controlled to operate at a volatilization temperature specific to the compound(s) sought to be separated and measured.

  20. Very high finesse optical-feedback cavity-enhanced absorption spectrometer for low concentration water vapor isotope analyses.

    PubMed

    Landsberg, J; Romanini, D; Kerstel, E

    2014-04-01

    So far, cavity-enhanced absorption spectroscopy (CEAS) has been based on optical cavities with a high finesse F that, however, has been limited by mirror reflectivity and by cavity transmission considerations to a few times 10,000. Here, we demonstrate a compact near-infrared optical-feedback CEAS instrument for water vapor isotope ratio measurements, with F>140,000. We show that this very high finesse can be effectively exploited to improve the detection sensitivity to the full extent predicted by the increased effective path length to reach a noise equivalent absorption sensitivity of 5.7×10(-11)  cm(-1) Hz(-1/2) for a full spectrum registration (including possible effects of interference fringes and fit model inadequacies). PMID:24686607

  1. [Detection of sorbic acid in food by homemade micro-spectrometer analytical system].

    PubMed

    Chuan, Na; Xu, Yi; Chen, Gang; Wen, Zhong-quan; He, Li; Wen, Zhi-yu

    2012-08-01

    A homemade micro-spectrometer analytical system was developed for the quantitative determination of the sorbic acid in the food based on the photometric principle. And with the standard addition method it was applied to eliminate the interference coming from the food substrate. The detecting result illustrated a good relativity in the range of 0-10.0 mg x L(-1) with the linear correlation coefficient of 0.9989, and the sample recovery was 99.2%-99.5% with RSD of 0.58%. The micro-spectrometer analysis system has shown potential prospective application in the fields of rapid and high performance detection for food additives. PMID:23156802

  2. System design of Fourier transform imaging spectrometer using tunable lateral shearing splitter

    NASA Astrophysics Data System (ADS)

    Meng, Xin; Li, Jianxin; Bai, Caixun; Zhu, Rihong

    2015-04-01

    The Fourier transform spectrometer without slit has the advantages of high radiation throughput and high spatial resolution. It can be used for detecting more details of the spectral and spatial information. We present the initial structure of the collimator and objective based on the analysis of the principle of the Fourier transform spectrometer. Then the collimator and objective are optimized by Zemax. The MTF of the cut-off frequency is great than 0.7. The tunable lateral shearing splitter is used as the interferometer, which makes the system more compact compared with the system using Sagnac lateral shearing splitter. The method to calculate the geometric dimension of the splitter is presented. Then the complete Fourier transform spectrometer is designed. The MTF of the cut-off frequency is great than 0.6. And the largest RMS of the spot is less than 6μm.

  3. Development of the data acquisition and control system for a portable THz time-domain spectrometer

    NASA Astrophysics Data System (ADS)

    Gao, Weibo; Wang, Yingxin; Zhao, Ziran

    2013-08-01

    This paper discusses the development of data acquisition and control system (DACS) for a portable terahertz time-domain spectrometer (THz-TDS). In this system, field programmable gate array (FPGA) severed as main control unit (MCU), which controls and harmonizes other functional modules of the spectrometer, including the linear delay stage, high voltage modulation and the AD converter. A digital lock-in amplifier implemented within the FPGA is employed to restore the weak THz signal. USB is used as the communication interface between the FPGA and the computer, which transfers commands and THz waveform data. The spectrometer can scan a waveform within a 30-ps time window in about 10 seconds, which has a spectral resolution better than 50GHz and a dynamic range up to 49dB.

  4. Dynamic interferometer alignment and its utility in UV Fourier transform spectrometer systems

    NASA Technical Reports Server (NTRS)

    Dorval, Rick K.; Engel, James R.; Wyntjes, Geert J.

    1993-01-01

    Dynamic alignment has been demonstrated as a practical approach to alignment maintenance for systems in the infrared region of the spectrum. On the basis of work done by OPTRA, this technique was introduced in commercial Fourier transform spectrometer systems in 1982 and in various forms is now available from a number of manufacturers. This paper reports on work by OPTRA to extend the basic technique to systems operating in the ultraviolet. In addition, this paper reports the preliminary results of the development of an alignment system using a laser diode in place of a gas laser normally found in dynamic alignment systems. A unique optical system and spatial heterodyne technique allows for achievement of a metrology system with characteristics that fully satisfy the requirements of an ultraviolet spectrometer system.

  5. Inter-comparison of 2 microm Heterodyne Differential Absorption Lidar, Laser Diode Spectrometer, LICOR NDIR analyzer and flasks measurements of near-ground atmospheric CO2 mixing ratio.

    PubMed

    Gibert, Fabien; Joly, Lilian; Xuéref-Rémy, Irène; Schmidt, Martina; Royer, Adrien; Flamant, Pierre H; Ramonet, Michel; Parvitte, Bertrand; Durry, Georges; Zéninari, Virginie

    2009-01-01

    Remote sensing and in situ instruments are presented and compared in the same location for accurate CO(2) mixing ratio measurements in the atmosphere: (1) a 2.064 microm Heterodyne DIfferential Absorption Lidar (HDIAL), (2) a field deployable infrared Laser Diode Spectrometer (LDS) using new commercial diode laser technology at 2.68 microm, (3) LICOR NDIR analyzer and (4) flasks. LDS, LICOR and flasks measurements were made in the same location, LICOR and flasks being taken as reference. Horizontal HDIAL measurements of CO(2) absorption using aerosol backscatter signal are reported. Using new spectroscopic data in the 2 microm band and meteorological sensor measurements, a mean CO(2) mixing ratio is inferred by the HDIAL in a 1 km long path above the 15m height location of the CO(2) in situ sensors. We compare HDIAL and LDS measurements with the LICOR data for 30 min of time averaging. The mean standard deviation of the HDIAL and the LDS CO(2) mixing ratio results are 3.3 ppm and 0.89 ppm, respectively. The bias of the HDIAL and the LDS measurements are -0.54 ppm and -0.99 ppm, respectively. PMID:18718810

  6. Device system and method for miniaturized radiation spectrometer

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, Epaminondas G. (Inventor)

    2008-01-01

    A device/system for radiation sensing is configured to detect high and low LET radiation. The radiation sensing system may include a high LET detector and a low LET detector coupled to the high LET detector by a CPU, wherein the high LET detector and the low LET detector are assembled within a single unit. The device/system may also include a high LET and low LET detector that may be coupled together without an internal CPU. Overall, the device/system may be a stand-alone system and/or coupled to an external processing device. The device/system may also be approximately 6.times.6.times.2 cm.sup.3 in size, making it hand portable and may weigh less or equal to approximately ninety (90) grams, and operate on less than or approximately 0.25 watts of power.

  7. Theoretical Study of New Combined Absorption-Ejector Refrigeration System

    NASA Astrophysics Data System (ADS)

    Abed, A. M.; Sopian, K.; Alghoul, M. A.; Al-Shamani, A. N.; Ruslan, M. H.; Mat, S.

    2015-09-01

    An improved system of the new combined single stage absorption cycle operated with NH3/H2O as working fluid was performed. In order to enhance performance the cycle a new configuration of absorption system was utilized. The performances of two configurations of the combined absorption cycle were compared; a) with common solution heat exchanger and b) divided the streamline of solution heat exchanger to recover the internal heat. Based on the analysis, it has been shown that the second configuration a significant reduction of the required generator and absorber loads by about 20% and 17% respectively, with increased coefficient of performance (COP) about 12% compared to the first configuration. This improvement in the overall COP is found due to improve energy utilization efficiency significantly.

  8. Spatially resolved spectrometer system for the ZT-40 device

    SciTech Connect

    Watt, R.G.

    1981-05-01

    A spatially resolved emission spectroscopy system designed for use on the ZT-40 device at the Los Alamos National Laboratory is described. The three-chord system consists of independent dispersive elements and detectors for each chord, on a common wavelength drive. The system has been installed and is currently in use on ZT-40. Preliminary results of CV (227.1 nm) line radiation measurements are presented.

  9. Laser sampling system for an inductively-coupled atomic emission spectrometer. Final report

    SciTech Connect

    1998-02-15

    A laser sampling system was attached to a Perkin Elmer Optima 3000 inductively-coupled plasma, atomic emission spectrometer that was already installed and operating in the Chemistry and Geochemistry Department at the Colorado School of Mines. The use of the spectrometer has been highly successful. Graduate students and faculty from at least four different departments across the CSM campus have used the instrument. The final report to NSF is appended to this final report. Appendices are included which summarize several projects utilizing this instrument: acquisition of an inductively-coupled plasma atomic emission spectrometer for the geochemistry program; hydrogen damage susceptibility assessment for high strength steel weldments through advanced hydrogen content analysis, 1996 and 1997 annual reports; and methods for determination of hydrogen distribution in high strength steel welds.

  10. Operation of a microchannel plate counting system in a mass spectrometer

    NASA Technical Reports Server (NTRS)

    Murphy, D. M.; Mauersberger, K.

    1985-01-01

    A multiplier detector system has been developed as part of a mass spectrometer in an ion counting mode. During its operation ions striking a microchannel plate release pulses of electrons which are accelerated to a phosphor layer. The resulting flash of light is carried by a fiber-optic bundle to a photodiode array. The detector simultaneously counts ions throughout a mass spectrum covering more than 30 amu. It extends the mass spectrometer's operation toward low count rates for trace gas analysis. Each mass peak can be independently measured at count rates between 0.1 and 1000 counts/s. Higher rates on a few peaks do not blind the entire detector. The detector's capabilities have been demonstrated by measuring Kr and Xe isotopes in air at natural abundances. The mass spectrometer, detector, and readout electronics are sufficiently compact to permit use in a balloon-borne experiment.

  11. Miniature Low Power Submillimeter-Wave Spectrometer For Detection of Water in The Solar System

    NASA Technical Reports Server (NTRS)

    Boric-Lubecke, Olga; Denning, Richard F.; Janssen, Michael A.; Frerking, Margaret A.

    1997-01-01

    Mass and power for the next generation of NASA's heterodyne spectrometers must be greatly reduced to satisfy the constraints of future small-spacecraft missions. Here we present a new receiver concept for remote sensing in the Solar System, with greatly reduced mass, power, and size compared to instruments implemented in current missions.

  12. A heavy ion spectrometer system for the measurement of projectile fragmentation of relativistic heavy ions

    NASA Astrophysics Data System (ADS)

    Engelage, J.; Crawford, H. J.; Albergo, S.; Kuo, C.; Caccia, Z.; Chen, C.-X.; Costa, S.; Cronqvist, M.; Flores, L.; Fonte, R.; Greiner, L.; Guzik, T. G.; Insolia, A.; Mitchell, J. W.

    1996-06-01

    The Heavy Ion Spectrometer System (HISS) at the LBL Bevalac provided a unique facility for measuring projectile fragmentation cross sections important in deconvolving the Galactic Cosmic Ray (GCR) source composition. The general characteristics of the apparatus specific to this application are described and the main features of the event reconstruction and analysis used in the TRANSPORT experiment are discussed.

  13. Postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared

    NASA Technical Reports Server (NTRS)

    Wiedermann, Guenter; Jennings, D. E.; Hanel, R. H.; Kunde, V. G.; Moseley, S. H.

    1989-01-01

    A postdispersion system for astronomical observations with Fourier transform spectrometers in the thermal infrared has been developed which improves the sensitivity of radiation noise limited observations by reducing the spectral range incident on the detector. Special attention is given to the first-generation blocked impurity band detector. Planetary, solar, and stellar observations are reported.

  14. Systems, methods, and apparatus of a low conductance silicon micro-leak for mass spectrometer inlet

    NASA Technical Reports Server (NTRS)

    Harpold, Dan N. (Inventor); Niemann, Hasso B. (Inventor); Jamieson, Brian G. (Inventor); Lynch, Bernard A. (Inventor)

    2011-01-01

    Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels.

  15. Systems, Methods, and Apparatus of a Low Conductance Silicon Micro-Leak for Mass Spectrometer Inlet

    NASA Technical Reports Server (NTRS)

    Harpold, Dan N. (Inventor); Niemann, Hasso B. (Inventor); Jamieson, Brian G. (Inventor); Lynch, Bernard A. (Inventor)

    2013-01-01

    Systems, methods and apparatus are provided through which in some embodiments a mass spectrometer micro-leak includes a number of channels fabricated by semiconductor processing tools and that includes a number of inlet holes that provide access to the channels.

  16. Optimization of fluorine determination via the molecular absorption of gallium mono-fluoride in a graphite furnace using a high-resolution continuum source spectrometer

    NASA Astrophysics Data System (ADS)

    Gleisner, Heike; Welz, Bernhard; Einax, Jürgen W.

    2010-09-01

    The determination of fluorine using the molecular absorption of gallium mono-fluoride (GaF) at the 211.248 nm rotational line has been optimized using a commercially available high-resolution continuum source atomic absorption spectrometer with a transversely heated graphite tube furnace. The electron excitation spectrum of GaF was generated by adding 500 μg Ga per injection into the graphite tube as molecule forming reagent. Best results were obtained by applying Zr as a permanent modifier and a mixed Pd/Zr modifier, thermally pretreated before each sample injection together with the Ga reagent at 1100 °C. The use of sodium acetate and Ru(III) nitrosyl nitrate as additional modifiers injected together with the sample further improved the performance. This way a maximum pyrolysis temperature of 550 °C could be used, and the optimum molecule forming temperature was 1550 °C. Several drinking water samples, a mineral water sample, and two certified reference materials were analyzed using the standard calibration technique; the absence of potential matrix effects was verified by measuring different dilutions and spiking with known fluorine mass. The results were in good agreement with the certified values and those measured by ion selective electrode; the recovery rate for the spiking experiments was between 97% and 106%. The results show that there was no matrix influence for that kind of samples containing relatively high concentrations of Ca, Mg and chloride, which are known to cause interference in GaF molecule absorption. The limit of detection and the characteristic mass of the method were 5.2 and 7.4 pg F, respectively, and were both about a factor of two better than recently published values.

  17. Waste heat driven absorption refrigeration process and system

    DOEpatents

    Wilkinson, William H.

    1982-01-01

    Absorption cycle refrigeration processes and systems are provided which are driven by the sensible waste heat available from industrial processes and other sources. Systems are disclosed which provide a chilled water output which can be used for comfort conditioning or the like which utilize heat from sensible waste heat sources at temperatures of less than 170.degree. F. Countercurrent flow equipment is also provided to increase the efficiency of the systems and increase the utilization of available heat.

  18. NHEXAS PHASE I REGION 5 STUDY--STANDARD OPERATING PROCEDURE FOR MAINTENANCE OF PERKIN ELMER (PE) MODEL ZL5100 PC ATOMIC ABSORPTION SPECTROMETER: GRAPHITE FURNACE (NHX/SOP-171-006)

    EPA Science Inventory

    This procedure describes maintenance practices for the Perkin Elmer (PE) Model ZL5100 PC atomic absorption spectrometer with graphite furnace. It was required that the procedure be performed daily by the instrument operator during periods of analysis and recorded in the instrumen...

  19. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) onboard calibration system

    NASA Technical Reports Server (NTRS)

    Chrien, Thomas G.; Eastwood, Mike; Green, Robert O.; Sarture, Charles; Johnson, Howell; Chovit, Chris; Hajek, Pavel

    1995-01-01

    The AVIRIS instrument uses an onboard calibration system to provide auxiliary calibration data. The system consist of a tungsten halogen cycle lamp imaged onto a fiber bundle through an eight position filter wheel. The fiber bundle illuminates the back side of the foreoptics shutter during a pre-run and post-run calibration sequence. The filter wheel contains two neutral density filters, five spectral filters and one blocked position. This paper reviews the general workings of the onboard calibrator system and discusses recent modifications.

  20. FTIR spectrometer with 30 m optical cell and its applications to the sensitive measurements of selective and nonselective absorption spectra

    NASA Astrophysics Data System (ADS)

    Ponomarev, Yu. N.; Solodov, A. A.; Solodov, A. M.; Petrova, T. M.; Naumenko, O. V.

    2016-07-01

    A description of the spectroscopic complex at V.E. Zuev Institute of Atmospheric Optics, SB RAS, operating in a wide spectral range with high threshold sensitivity to the absorption coefficient is presented. Measurements of weak lines and nonselective spectra of CO2 and H2O were performed based on the built setup. As new application of this setup, positions and intensities of 152 weak lines of H2O were measured between 2400 and 2560 cm-1 with threshold sensitivity of 8.6×10-10 cm-1, and compared with available calculated and experimental data. Essential deviations between the new intensity measurements and calculated data accepted in HITRAN 2012 and GEISA 2015 forthcoming release are found.

  1. Study of Comet Nucleus Gamma-Ray Spectrometer Penetration System

    NASA Technical Reports Server (NTRS)

    Adams, G. L.; Amundsen, R. J.; Beardsley, R. W.; Cash, R. H.; Clark, B. C.; Knight, T. C. D.; Martin, J. P.; Monti, P.; Outteridge, D. A.; Plaster, W. D.

    1986-01-01

    A penetrator system has been suggested as an approach for making in situ measurements of the composition and physical properties of the nucleus of a comet. This study has examined in detail the feasibility of implementing the penetrator concept. The penetrator system and mission designs have been developed and iterated in sufficient detail to provide a high level of confidence that the concept can be implemented within the constraints of the Mariner Mark 2 spacecraft.

  2. Comparisons of the DSPEC and DSPEC Plus spectrometer systems

    SciTech Connect

    Duc T. Vo

    1999-11-01

    A previous experimental evaluation of nine commercial gamma-ray spectroscopy systems demonstrated significant benefits of digital signal processing for improvements in the performance of high-resolution gamma-ray spectroscopy systems. Spectacular improvements in the energy resolution and throughput of germanium detectors were demonstrated for the DSPEC. Recently, a new, improved version of DSPEC, the DSPEC Plus, was developed. Results of the performance of the DSPEC Plus are compared to those of the DSPEC.

  3. Fully digital data acquisition system for the neutron time-of-flight spectrometer TOFOR at JET

    SciTech Connect

    Skiba, M.; Weiszflog, M.; Hjalmarsson, A.; Ericsson, G.; Hellesen, C.; Conroy, S.; Andersson-Sunden, E.; Eriksson, J.; Binda, F.; Collaboration: JET-EFDA Contributors

    2012-10-15

    A prototype of a fully digital data acquisition system based on 1 Gsps 12 bit digitizers for the TOFOR fusion neutron spectrometer at JET is assessed. The prototype system enables the use of geometry-based background discrimination techniques, which are modeled, evaluated, and compared to experimental data. The experimental results are in line with the models and show a significant improvement in signal-to-background ratio in measured time-of-flight spectrum compared to the existing data acquisition system.

  4. Elimination of ``memory`` from sample handling and inlet system of a mass spectrometer

    DOEpatents

    Chastgner, P.

    1991-05-08

    This paper describes a method for preparing the sample handling and inlet system of a mass spectrometer for analysis of a subsequent sample following analysis of a previous sample comprising the flushing of the system interior with supercritical CO{sub 2} and venting the interior. The method eliminates the effect of system ``memory`` on the subsequent analysis, especially following persistent samples such as xenon and krypton.

  5. A COMPUTER CONTROL AND ACQUISITION SYSTEM FOR ATOMIC ABSORPTION DATA

    EPA Science Inventory

    A system is presented that controls and acquires data from a Perkin-Elmer 603 or similar atomic absorption spectrophotometer operating in the flame mode and equipped with a 200 place auto-sampler. The hardware consists of a PDP11 computer with minimum peripheral equipment and a s...

  6. Using the transportable, computer-operated, liquid-scintillator fast-neutron spectrometer system

    SciTech Connect

    Thorngate, J.H.

    1988-11-01

    When a detailed energy spectrum is needed for radiation-protection measurements from approximately 1 MeV up to several tens of MeV, organic-liquid scintillators make good neutron spectrometers. However, such a spectrometer requires a sophisticated electronics system and a computer to reduce the spectrum from the recorded data. Recently, we added a Nuclear Instrument Module (NIM) multichannel analyzer and a lap-top computer to the NIM electronics we have used for several years. The result is a transportable fast-neutron spectrometer system. The computer was programmed to guide the user through setting up the system, calibrating the spectrometer, measuring the spectrum, and reducing the data. Measurements can be made over three energy ranges, 0.6--2 MeV, 1.1--8 MeV, or 1.6--16 MeV, with the spectrum presented in 0.1-MeV increments. Results can be stored on a disk, presented in a table, and shown in graphical form. 5 refs., 51 figs.

  7. Development of a high vacuum sample preparation system for helium mass spectrometer

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Das, N. K.; Mallik, C.; Bhandari, R. K.

    2012-11-01

    A high vacuum sample preparation system for the 3He/4He ratio mass spectrometer (Helix SFT) has been developed to remove all the gaseous constituents excluding helium from the field gases. The sample preparation system comprises of turbo molecular pump, ion pump, zirconium getter, pipettes and vacuum gauges with controller. All these are fitted with cylindrical SS chamber using all metal valves. The field samples are initially treated with activated charcoal trap immersed in liquid nitrogen to cutoff major impurities and moisture present in the sample gas. A sample of 5 ml is collected out of this stage at a pressure of 10-2 mbar. This sample is subsequently purified at a reduced pressure of 10-7 mbar before it is injected into the ion source of the mass spectrometer. The sample pressure was maintained below 10-7 mbar with turbo molecular vacuum pumps and ion pumps. The sample gas passes through several getter elements and a cold finger with the help of manual high vacuum valves before it is fed to the mass spectrometer. Thus the high vacuum sample preparation system introduces completely clean, dry and refined helium sample to the mass spectrometer for best possible analysis of isotopic ratio of helium.

  8. Volcanic Gas Emissions Mapping Using a Mass Spectrometer System

    NASA Technical Reports Server (NTRS)

    Griffin, Timothy P.; Diaz, J. Andres

    2008-01-01

    The visualization of hazardous gaseous emissions at volcanoes using in-situ mass spectrometry (MS) is a key step towards a better comprehension of the geophysical phenomena surrounding eruptive activity. In-Situ gas data consisting of helium, carbon dioxide, sulfur dioxide, and other gas species, were acquired with an MS system. MS and global position system (GPS) data were plotted on ground imagery, topography, and remote sensing data collected by a host of instruments during the second Costa Rica Airborne Research and Technology Applications (CARTA) mission This combination of gas and imaging data allowed 3-dimensional (3-D) visualization of the volcanic plume end the mapping of gas concentration at several volcanic structures and urban areas This combined set of data has demonstrated a better tool to assess hazardous conditions by visualizing and modeling of possible scenarios of volcanic activity. The MS system is used for in-situ measurement of three-dimensional gas concentrations at different volcanic locations with three different transportation platforms, aircraft, auto, and hand carried. The demonstration for urban contamination mapping is also presented as another possible use for the MS system.

  9. Automated mass spectrometer/analysis system: A concept

    NASA Technical Reports Server (NTRS)

    Boettger, H. G.; Giffin, C. E.; Dreyer, W. J.; Kuppermann, A.

    1975-01-01

    System performs rapid multiple analyses of entire compound classes or individual compounds on small amounts of sample and reagent. Method will allow screening of large populations for metabolic disorders and establishment of effective-but-safe levels of therapeutic drugs in body fluids and tissues.

  10. Backscatter absorption gas imaging systems and light sources therefore

    DOEpatents

    Kulp, Thomas Jan; Kliner, Dahv A. V.; Sommers, Ricky; Goers, Uta-Barbara; Armstrong, Karla M.

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  11. Home-built magnetic resonance imaging system (0.3 T) with a complete digital spectrometer

    NASA Astrophysics Data System (ADS)

    Jie, Shen; Qin, Xu; Ying, Liu; Gengying, Li

    2005-10-01

    A home-built magnetic resonance imaging (MRI) system with a complete digital spectrometer has been designed for investigation of plants and animals. With the application of the latest digital integrated circuit technology, the digital spectrometer is greatly simplified without the loss of flexibility and performance. A powerful pulse sequence compiler with a graphical editor can allow the user to edit the pulse sequence more easily and more conveniently than ever before. Moreover, a permanent magnet capable of producing a 180 mm diam spherical homogeneous region is employed in our MRI system to ensure a comparatively large image size. Compared with previous work, our MRI system has the features of flexibility, relatively large imaging size, and low cost. Experimental results obtained with the proposed system are presented in this article.

  12. Field-deployed underwater mass spectrometers for investigations of transient chemical systems.

    PubMed

    Kibelka, Gottfried P G; Timothy Short, R; Toler, Strawn K; Edkins, John E; Byrne, Robert H

    2004-11-15

    The mass spectrometer developments and underwater deployments described in this work are directed toward observations of important reactive and influential inorganic and organic chemicals. Mass spectrometer systems for measurement of dissolved gases and volatile hydrocarbons were created by coupling a membrane analyte-introduction system with linear quadrupole and ion trap mass analyzers. For molecular masses up to 100amu, the in situ quadrupole system has detection limits on the order of 1-5ppb. For masses up to approximately 300amu, the underwater ion trap system detects many volatile hydrocarbons at concentrations below 1ppb. Both instruments can function autonomously or via interactive communications from a remote control site. Continuous operations can be sustained for up to approximately 12 days. Deployments have initially involved shallow water proof-of-concept operations at depths less than 30m. Future modifications are planned that will allow operational depths to 200m. PMID:18969697

  13. NASA Charge Coupled Device (CCD) Spectrometer System (NCSS)

    NASA Technical Reports Server (NTRS)

    Wright, C. W.; Bailey, S. A.; Piazza, C. R.

    1988-01-01

    A small lightweight NCSS was designed, constructed, and is now being bench tested at Wallops. The unit provides 256, 2.7 nm wide channels in the visible spectrum from approximately 400 to 1100 nm. The present input slit provides a spectral impulse response of about 10 nm. Up to five NCSS sensors may be bused to one data system interface. The NCSS contains a high speed, 16 bit analog to digital converter (ADC) with an integral wide-band sample-and-hold amplifier. The NCSS was developed primarily for use with the Airbone Oceanographic Lidar (AOL). A prototype NCSS is presently interfaced to the AOL. The AOL will use two new NCSS units onboard the Goddard P-3A aircraft. They will provide the AOL with high resolution sky and ocean spectra. The up-looking NCSS will provide the AOL data system (AOLDS) with down-welling solar radiance, and the down-looking NCSS will provide ocean color spectra. The solar radiance will be used to correct various ocean color algorithms now being researched.

  14. NASA Charge Coupled Device (CCD) Spectrometer System (NCSS)

    NASA Astrophysics Data System (ADS)

    Wright, C. W.; Bailey, S. A.; Piazza, C. R.

    A small lightweight NCSS was designed, constructed, and is now being bench tested at Wallops. The unit provides 256, 2.7 nm wide channels in the visible spectrum from approximately 400 to 1100 nm. The present input slit provides a spectral impulse response of about 10 nm. Up to five NCSS sensors may be bused to one data system interface. The NCSS contains a high speed, 16 bit analog to digital converter (ADC) with an integral wide-band sample-and-hold amplifier. The NCSS was developed primarily for use with the Airbone Oceanographic Lidar (AOL). A prototype NCSS is presently interfaced to the AOL. The AOL will use two new NCSS units onboard the Goddard P-3A aircraft. They will provide the AOL with high resolution sky and ocean spectra. The up-looking NCSS will provide the AOL data system (AOLDS) with down-welling solar radiance, and the down-looking NCSS will provide ocean color spectra. The solar radiance will be used to correct various ocean color algorithms now being researched.

  15. Relativistic heavy ion fragmentation at HISS (Heavy Ion Spectrometer System)

    SciTech Connect

    Tull, C.E.

    1990-10-01

    An experiment was conducted at the Lawrence Berkeley Laboratory to measure projectile fragmentation of relativistic heavy ions. Charge identification was obtained by the use of a Cerenkov Hodoscope operating above the threshold for total internal reflection, while velocity measurement was performed by use of a second set of Cerenkov radiators operating at the threshold for total internal reflection. Charge and mass resolution for the system was {sigma}{sub Z} = 0.2 e and {sigma}{sub A} = 0.2 u. Measurements of the elemental and isotopic production cross sections for the fragmentation of {sup 40}Ar at 1.65{center dot}A GeV have been compared with an Abrasion-Ablation Model based on the evaporation computer code GEMINI. The model proves to be an accurate predictor of the cross sections for fragments between Chlorine and Boron. The measured cross section were reproduced using simple geometry with charge dispersions induced by zero-point vibrations of the giant dipole resonance for the prompt abrasion stage, and injecting an excitation energy spectrum based on a final state interaction with scaling factor E{sub fsi} = 38.8 MeV/c. Measurement of the longitudinal momentum distribution widths for projectile fragments are consistent with previous experiment and can be interpreted as reflecting the Fermi momentum distribution in the initial projectile nucleus. Measurement of the transverse momentum indicate an additional, unexplained dependence of the reduced momentum widths on fragment mass. This dependence has the same sign and similar slope to previously measured fragments of {sup 139}La, and to predictions based on phase-space constraints on the final state of the system.

  16. NASA three-laser airborne differential absorption lidar system electronics

    NASA Technical Reports Server (NTRS)

    Allen, R. J.; Copeland, G. D.

    1984-01-01

    The system control and signal conditioning electronics of the NASA three laser airborne differential absorption lidar (DIAL) system are described. The multipurpose DIAL system was developed for the remote measurement of gas and aerosol profiles in the troposphere and lower stratosphere. A brief description and photographs of the majority of electronics units developed under this contract are presented. The precision control system; which includes a master control unit, three combined NASA laser control interface/quantel control units, and three noise pulse discriminator/pockels cell pulser units; is described in detail. The need and design considerations for precision timing and control are discussed. Calibration procedures are included.

  17. Molecular absorption cryogenic cooler for liquid hydrogen propulsion systems

    NASA Technical Reports Server (NTRS)

    Klein, G. A.; Jones, J. A.

    1982-01-01

    A light weight, long life molecular absorption cryogenic cooler (MACC) system is described which can use low temperature waste heat to provide cooling for liquid hydrogen propellant tanks for interplanetary spacecraft. Detailed tradeoff studies were made to evaluate the refrigeration system component interactions in order to minimize the mass of the spacecraft cooler system. Based on this analysis a refrigerator system mass of 31 kg is required to provide the .48 watts of cooling required by a 2.3 meter diameter liquid hydrogen tank.

  18. Co-Alignment System (CAS) study. Report on task 1-3. [Solar Extreme Ultraviolet Telescope and Spectrometer pointing system

    NASA Technical Reports Server (NTRS)

    Anderson, N. T.

    1980-01-01

    The design of a suitable coalignment system (CAS) for the Solar Extreme Ultraviolet Telescope and Spectrometer (SEUTS) is presented. The CAS provides offset adjustment capabilities to SEUTS which will be mounted on a single large pointing system with other devices. The suitability of existing designs is determined and modifications are suggested.

  19. The development and evaluation of airborne in situ N2O and CH4 sampling using a Quantum Cascade Laser Absorption Spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Le Breton, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.; Bauguitte, S. J.-B.; O'Shea, S. J.; Muller, J. B. A.; Zahniser, M. S.; Pyle, J.; Palmer, P. I.

    2015-08-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large Atmospheric Research Aircraft. We present details of the mid-IR Aerodyne Research Inc. Quantum Cascade Laser Absorption Spectrometer (QCLAS) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure is presented. Total 1σ uncertainties of 1.81 ppb for CH4 and 0.35 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Los Gatos Research Fast Greenhouse Gas Analyser (FGGA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

  20. The development and evaluation of airborne in situ N2O and CH4 sampling using a Quantum Cascade Laser Absorption Spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Le Breton, M. R.; Allen, G.; Percival, C.; Gallagher, M. W.; Bauguitte, S.; O'Shea, S.; Muller, J.; Zahniser, M. S.; Pyle, J. A.; Palmer, P. I.

    2015-12-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large Atmospheric Research Aircraft. We evaluate the performance of the mid-IR continuous wave Aerodyne Research Inc. Quantum Cascade Laser Absorption Spectrometer (QCLAS) employed over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. Test flight data demonstrating the sensitivity of the instrument to changes in cabin pressure is presented, and a new in-flight calibration procedure to account for this issue is described and assessed. Total 1σ uncertainties of 1.81 ppb for CH4 and 0.35 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Los Gatos Research Fast Greenhouse Gas Analyser (FGGA).

  1. The development and evaluation of airborne in situ N2O and CH4 sampling using a Quantum Cascade Laser Absorption Spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, Joseph; Le Breton, Michael; Allen, Grant; Percival, Carl; Gallagher, Martin; Bauguitte, Stephane; O'Shea, Sebastian; Muller, Jennifer; Zahniser, Mark; Pyle, John; Palmer, Paul

    2016-04-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large Atmospheric Research Aircraft. We evaluate the performance of the mid-IR continuous wave Aerodyne Research Inc. Quantum Cascade Laser Absorption Spectrometer (QCLAS) employed over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. Test flight data demonstrating the sensitivity of the instrument to changes in cabin pressure is presented, and a new in-flight calibration procedure to account for this issue is described and assessed. Total 1σ uncertainties of 1.81 ppb for CH4 and 0.35 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Los Gatos Research Fast Greenhouse Gas Analyser (FGGA).

  2. The development and evaluation of airborne in situ N2O and CH4 sampling using a quantum cascade laser absorption spectrometer (QCLAS)

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Le Breton, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.; Bauguitte, S. J.-B.; O'Shea, S. J.; Muller, J. B. A.; Zahniser, M. S.; Pyle, J.; Palmer, P. I.

    2016-01-01

    Spectroscopic measurements of atmospheric N2O and CH4 mole fractions were made on board the FAAM (Facility for Airborne Atmospheric Measurements) large atmospheric research aircraft. We present details of the mid-infrared quantum cascade laser absorption spectrometer (QCLAS, Aerodyne Research Inc., USA) employed, including its configuration for airborne sampling, and evaluate its performance over 17 flights conducted during summer 2014. Two different methods of correcting for the influence of water vapour on the spectroscopic retrievals are compared and evaluated. A new in-flight calibration procedure to account for the observed sensitivity of the instrument to ambient pressure changes is described, and its impact on instrument performance is assessed. Test flight data linking this sensitivity to changes in cabin pressure are presented. Total 1σ uncertainties of 2.47 ppb for CH4 and 0.54 ppb for N2O are derived. We report a mean difference in 1 Hz CH4 mole fraction of 2.05 ppb (1σ = 5.85 ppb) between in-flight measurements made using the QCLAS and simultaneous measurements using a previously characterised Fast Greenhouse Gas Analyser (FGGA, Los Gatos Research, USA). Finally, a potential case study for the estimation of a regional N2O flux using a mass balance technique is identified, and the method for calculating such an estimate is outlined.

  3. Infrared absorption of gaseous benzoylperoxy radical C6H5C(O)OO recorded with a step-scan Fourier-transform spectrometer.

    PubMed

    Golec, Barbara; Chen, Jin-Dah; Lee, Yuan-Pern

    2011-12-14

    A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the transient species produced in gaseous reactions of benzoyl radical, C(6)H(5)CO, with O(2). C(6)H(5)CO was produced either from photolysis of acetophenone, C(6)H(5)C(O)CH(3), at 248 nm, or from photolysis of a mixture of benzaldehyde, C(6)H(5)CHO, and Cl(2) at 355 nm. Two intense bands near 1830 and 1226 cm(-1) are assigned to the C=O stretching (ν(6)) and the C-C stretching mixed with C-H deformation (ν(13)) modes, and two weaker bands near 1187 and 1108 cm(-1) are assigned to the ν(14) (C-H deformation) and ν(16) (O-O stretching /C-H deformation) modes of C(6)H(5)C(O)OO, the benzoylperoxy radical. These observed vibrational wave numbers and relative infrared intensities agree with those reported for syn-C(6)H(5)C(O)OO isolated in solid Ar and values predicted for syn-C(6)H(5)C(O)OO with the B3LYP/cc-pVTZ method. The simulated rotational contours of the two intense bands based on rotational parameters predicted with the B3LYP∕cc-pVTZ method fit satisfactorily with experimental results. PMID:22168689

  4. β - γ and β-neutron- γ emission in mass A=137 Decay Chain Studied with the Modular Total Absorption Spectrometer (MTAS)

    NASA Astrophysics Data System (ADS)

    Rasco, Charles; Fijałkowska, Aleksandra; Karny, Marek; Rykaczewski, Krzysztof; Wolińska-Cichocka, Marzena; Grzywacz, Robert

    2013-10-01

    The Modular Total Absorption Spectrometer (MTAS) is a detector made up of 19 separate hexagon modules of NaI which results in over a ton of NaI in the MTAS detector. MTAS was designed to capture as much of the electromagnetic energy release in β-decays as possible. MTAS was constructed at the Holifield Radioactive Ion Beam Facility and measured over 20 decay products of 238U fission products in its inaugural measurement campaign in January 2012. The measurements were focused on nuclei identified as important for decay heat analysis of the nuclear fuel cycle. Silicon detectors placed at the center of MTAS to provide β triggers, make for extremely clean signals in MTAS. Preliminary results on the average electromagnetic energy release in the β decay of 137Xe and 137I isotopes will be presented. These isotopes are among the priority 1 cases listed by the NEA. The 137I also has a beta -neutron decay branch that is detected in MTAS. Neutron detection in a large NaI detector will also be discussed. This work was supported by the US DOE by award no. DE-FG02-96ER40978 and by US DOE, Office of Nuclear Physics.

  5. Infrared absorption of gaseous benzoylperoxy radical C6H5C(O)OO recorded with a step-scan Fourier-transform spectrometer

    NASA Astrophysics Data System (ADS)

    Golec, Barbara; Chen, Jin-Dah; Lee, Yuan-Pern

    2011-12-01

    A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the transient species produced in gaseous reactions of benzoyl radical, C6H5CO, with O2. C6H5CO was produced either from photolysis of acetophenone, C6H5C(O)CH3, at 248 nm, or from photolysis of a mixture of benzaldehyde, C6H5CHO, and Cl2 at 355 nm. Two intense bands near 1830 and 1226 cm-1 are assigned to the C=O stretching (ν6) and the C-C stretching mixed with C-H deformation (ν13) modes, and two weaker bands near 1187 and 1108 cm-1 are assigned to the ν14 (C-H deformation) and ν16 (O-O stretching /C-H deformation) modes of C6H5C(O)OO, the benzoylperoxy radical. These observed vibrational wave numbers and relative infrared intensities agree with those reported for syn-C6H5C(O)OO isolated in solid Ar and values predicted for syn-C6H5C(O)OO with the B3LYP/cc-pVTZ method. The simulated rotational contours of the two intense bands based on rotational parameters predicted with the B3LYP/cc-pVTZ method fit satisfactorily with experimental results.

  6. Data processing system for the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory-F (OGO-F) satellite

    NASA Technical Reports Server (NTRS)

    Cronin, A. G.; Delaney, J. R.

    1973-01-01

    The system is discussed which was developed to process digitized telemetry data from the intensity monitoring spectrometer flown on the Orbiting Geophysical Observatory (OGO-F) Satellite. Functional descriptions and operating instructions are included for each program in the system.

  7. High-Resolution Spectroscopy of Quasars and Quasar Absorption-Line Systems

    NASA Technical Reports Server (NTRS)

    Shull, J. Michael

    1995-01-01

    Topic cover in this paper included new observations of QSO absorption lines by the Keck Telescope HIRES spectrometer and the Hubble Space Telescope. An overview of the major scientific issues in this field is followed by a brief summary of a panel discussion that addressed future instrumental possibilities that could answer some of these questions.

  8. Compact Infrared Spectrometers

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis

    2009-01-01

    Concentric spectrometer forms are advantageous for constructing a variety of systems spanning the entire visible to infrared range. Spectrometer examples are given, including broadband or high resolution forms. Some issues associated with the Dyson catadioptric type are also discussed.

  9. Stabilized master laser system for differential absorption lidar.

    PubMed

    Dinovitser, Alex; Hamilton, Murray W; Vincent, Robert A

    2010-06-10

    Wavelength accuracy and stability are key requirements for differential absorption lidar (DIAL). We present a control and timing design for the dual-stabilized cw master lasers in a pulsed master-oscillator power-amplifier configuration, which forms a robust low-cost water-vapor DIAL transmitter system. This design operates at 823 nm for water-vapor spectroscopy using Fabry-Perot-type laser diodes. However, the techniques described could be applied to other laser technologies at other wavelengths. The system can be extended with additional off-line or side-line wavelengths. The on-line master laser is locked to the center of a water absorption line, while the beat frequency between the on-line and the off-line is locked to 16 GHz using only a bandpass microwave filter and low-frequency electronics. Optical frequency stabilities of the order of 1 MHz are achieved. PMID:20539344

  10. A plastic scintillator-based muon tomography system with an integrated muon spectrometer

    NASA Astrophysics Data System (ADS)

    Anghel, V.; Armitage, J.; Baig, F.; Boniface, K.; Boudjemline, K.; Bueno, J.; Charles, E.; Drouin, P.-L.; Erlandson, A.; Gallant, G.; Gazit, R.; Godin, D.; Golovko, V. V.; Howard, C.; Hydomako, R.; Jewett, C.; Jonkmans, G.; Liu, Z.; Robichaud, A.; Stocki, T. J.; Thompson, M.; Waller, D.

    2015-10-01

    A muon scattering tomography system which uses extruded plastic scintillator bars for muon tracking and a dedicated muon spectrometer that measures scattering through steel slabs has been constructed and successfully tested. The atmospheric muon detection efficiency is measured to be 97% per plane on average and the average intrinsic hit resolution is 2.5 mm. In addition to creating a variety of three-dimensional images of objects of interest, a quantitative study has been carried out to investigate the impact of including muon momentum measurements when attempting to detect high-density, high-Z material. As expected, the addition of momentum information improves the performance of the system. For a fixed data-taking time of 60 s and a fixed false positive fraction, the probability to detect a target increases when momentum information is used. This is the first demonstration of the use of muon momentum information from dedicated spectrometer measurements in muon scattering tomography.

  11. Energy analysis of an ammonia-water absorption refrigeration system

    SciTech Connect

    Dincer, I.; Dost, S.

    1996-09-01

    Absorption refrigeration systems (ARSs) are run on heat-operated cycles. In these systems a secondary fluid (i.e., absorbent) is used to absorb the primary fluid (i.e., refrigerant) vaporized in the evaporator. ARSs for industrial and domestic applications have been attracting increasing interest throughout the world. A simple energy analysis technique for ammonia-water refrigeration systems is presented and verified with actual experimental data taken from the literature. Comparison was made in terms of the coefficient of performance, and very good agreement was found.

  12. High Performance Drying System Using Absorption Temperature Amplifier

    NASA Astrophysics Data System (ADS)

    Nomura, Tomohiro; Nishimura, Nobuya; Yabushita, Akihiro; Kashiwagi, Takao

    It is highly essential to create a high performance drying technology from the viewpoint of energy conservation. Recently the drying process using superheated steam has received a great attention for improving the energy efficiency of the conventional air drying processes. Many other advantages of this superheated steam drying include its inert atmosphere, enhanced drying rate, improved product quality and easier control. This study presents a new concept of superheated steam drying in which the absorption temperature amplifier is effectively applied in order to recover the waste heat with high efficiency. A feature of this new drying system is that, owing to a closed circuit dryer, the consumption of heating energy decreases by approximately 50% of the conventional noncirculated one, and the superheated steam conventionally discharged so as to maintain the pressure of the dryer at an atmospheric one can be reused as heating energy for the generator of the absorption temperature amplifier. In the 1st report, thermal performances of this proposed system have been analyzed by a computer simulation developed for the solar-assisted absorption heat transformer model at the steady-state operating condition. It may be fair to conclude that this drying system satisfies the desired operating conditions, although it involves some problems to be solved further in detail in future.

  13. A 100 kHz Time-Resolved Multiple-Probe Femtosecond to Second Infrared Absorption Spectrometer.

    PubMed

    Greetham, Gregory M; Donaldson, Paul M; Nation, Charlie; Sazanovich, Igor V; Clark, Ian P; Shaw, Daniel J; Parker, Anthony W; Towrie, Michael

    2016-04-01

    We present a dual-amplifier laser system for time-resolved multiple-probe infrared (IR) spectroscopy based on the ytterbium potassium gadolinium tungstate (Yb:KGW) laser medium. Comparisons are made between the ytterbium-based technology and titanium sapphire laser systems for time-resolved IR spectroscopy measurements. The 100 kHz probing system provides new capability in time-resolved multiple-probe experiments, as more information is obtained from samples in a single experiment through multiple-probing. This method uses the high repetition-rate probe pulses to repeatedly measure spectra at 10 µs intervals following excitation allowing extended timescales to be measured routinely along with ultrafast data. Results are presented showing the measurement of molecular dynamics over >10 orders of magnitude in timescale, out to 20 ms, with an experimental time response of <200 fs. The power of multiple-probing is explored through principal component analysis of repeating probe measurements as a novel method for removing noise and measurement artifacts. PMID:26887988

  14. [Design of optical system for solar extreme-ultraviolet imaging spectrometer].

    PubMed

    Liu, Zhuang; Gong, Yan

    2012-03-01

    Hyper-spectral imaging observation of the sun in the EUV region is an important method of research for solar's upper transition region, corona and plasma's physical property. Based on the application objective of solar extreme ultraviolet imaging spectrometer (SEUIS), combined with the current states of domestic and foreign extreme ultraviolet imaging spectrometer, a few of parameters for SEUIS design were drew up in the present paper. The advantages and disadvantages of all kinds of optical configurations were discussed,and the configuration of combination of telescope and spectrometer was chosen. The available main components were also described, off-axis parabolic mirror was chosen for telescope, and a high density uniform-line-space toroidal grating for dispersion device. The optical system which satisfies the performance parameters was designed. The design process, detailed parameters and results were presented in the end. The working wavelength of the optics system is 17.0-21.0 nm, the field of view is 1 228" x 1 024", the spatial resolution is 0.8 arc sec x pixel(-1), the spectral resolution is about 0.00198 nm x pixel(-1), and the total length of system is about 2.8 m. PMID:22582664

  15. Triple loop heat exchanger for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    A triple loop heat exchanger for an absorption refrigeration system is disclosed. The triple loop heat exchanger comprises portions of a strong solution line for conducting relatively hot, strong solution from a generator to a solution heat exchanger of the absorption refrigeration system, conduit means for conducting relatively cool, weak solution from the solution heat exchanger to the generator, and a bypass system for conducting strong solution from the generator around the strong solution line and around the solution heat exchanger to an absorber of the refrigeration system when strong solution builds up in the generator to an undesirable level. The strong solution line and the conduit means are in heat exchange relationship with each other in the triple loop heat exchanger so that, during normal operation of the refrigeration system, heat is exchanged between the relatively hot, strong solution flowing through the strong solution line and the relatively cool, weak solution flowing through the conduit means. Also, the strong solution line and the bypass system are in heat exchange relationship in the triple loop heat exchanger so that if the normal flow path of relatively hot, strong solution flowing from the generator to an absorber is blocked, then this relatively, hot strong solution which will then be flowing through the bypass system in the triple loop heat exchanger, is brought into heat exchange relationship with any strong solution which may have solidified in the strong solution line in the triple loop heat exchanger to thereby aid in desolidifying any such solidified strong solution.

  16. Equilibrator-based measurements of dissolved nitrous oxide in the surface ocean using an integrated cavity output laser absorption spectrometer

    NASA Astrophysics Data System (ADS)

    Grefe, I.; Kaiser, J.

    2014-06-01

    Dissolved nitrous oxide (N2O) concentrations are usually determined by gas chromatography (GC). Here we present laboratory tests and initial field measurements using a novel setup comprising a commercially available laser-based analyser for N2O, carbon monoxide and water vapour coupled to a glass-bed equilibrator. This approach is less labour-intensive and provides higher temporal and spatial resolution than the conventional GC technique. The standard deviation of continuous equilibrator or atmospheric air measurements was 0.2 nmol mol-1 (averaged over 5 min). The short-term repeatability for reference gas measurements within 1 h of each other was 0.2 nmol mol-1 or better. Another indicator of the long-term stability of the analyser is the standard deviation of the calibrated N2O mole fraction in marine air, which was between 0.5 and 0.7 nmol mol-1. The equilibrator measurements were compared with purge-and-trap gas chromatography-mass spectrometry (GC-MS) analyses of N2O concentrations in discrete samples from the Southern Ocean and showed agreement to within the 2% measurement uncertainty of the GC-MS method. The equilibrator response time to concentration changes in water was from 142 to 203 s, depending on the headspace flow rate. The system was tested at sea during a north-to-south transect of the Atlantic Ocean. While the subtropical gyres were slightly undersaturated, the equatorial region was a source of nitrous oxide to the atmosphere, confirming previous findings (Forster et al., 2009). The ability to measure at high temporal and spatial resolution revealed submesoscale variability in dissolved N2O concentrations. Mean sea-to-air fluxes in the tropical and subtropical Atlantic ranged between -1.6 and 0.11 μmol m-2 d-1 and confirm that the subtropical Atlantic is not an important source region for N2O to the atmosphere, compared to global average fluxes of 0.6-2.4 μmol m-2 d-1. The system can be easily modified for autonomous operation on voluntary

  17. Absorption and adsorption chillers applied to air conditioning systems

    NASA Astrophysics Data System (ADS)

    Kuczyńska, Agnieszka; Szaflik, Władysław

    2010-07-01

    This work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperature Tdes = 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling water Tc = 25 °C and temperature in evaporator Tevap = 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

  18. High Performance Drying System Using Absorption Temperature Amplifier

    NASA Astrophysics Data System (ADS)

    Nishimura, Nobuya; Nomura, Tomohiro; Yabushita, Akihiro; Kashiwagi, Takao

    A computer simulation has been developed on transient drying process in order to predict the dynamic thermal performance of a new superheated steam drying system using an absorption type temperature amplifier as a steam superheater. A feature of this drying system is that one can reuse the exhausted superheated stream conventionally discharged from the dryer as a driving heat source for the generator in this heat pump. But in the transient drying process, the evaporation of moisture sharply decreases. Accordingly, it is hardly expected to reuse an exhausted superheated steam as heating source for the generator. 80 the effects of this exhausted superheated steam and of changes in hot water and the cooling water temperatures were mainly investigated checking whether this drying system can be driven directly by the low level energy of sun or waste heat. Furthermore, the system performances of this drying system were evaluated on a qualitative-basis by using the exergy efficiency. The results show that, under the transient drying conditions, the temperature boost of superheated steam is possible at a high temperature and thus the absorption type temperature amplifier can be an effective steam superheater system.

  19. A molecular beam/quadrupole mass spectrometer system with synchronized beam modulation and digital waveform analysis

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Adams, B. R.

    1983-01-01

    A performance evaluation is conducted for a molecular beam/mass spectrometer (MB/MS) system, as applied to a 1-30 torr microwave-discharge flow reactor (MWFR) used in the formation of the methylperoxy radical and a study of its subsequent destruction in the presence or absence of NO(x). The modulated MB/MS system is four-staged and differentially pumped. The results obtained by the MWFR study is illustrative of overall system performance, including digital waveform analysis; significant improvements over previous designs are noted in attainable S/N ratio, detection limit, and accuracy.

  20. Design of a grating spectrometer from a 1:1 Offner mirror system

    NASA Technical Reports Server (NTRS)

    Kwo, Deborah; Lawrence, George; Chrisp, Michael

    1987-01-01

    A 1:1 Offner mirror system is modified to work as a grating spectrometer for the infrared by placing a grating on the secondary convex mirror of the system. Slight adjustment of the configuration combined with tilt of the secondary provide the necessary degrees of freedom to correct for astigmatism of the system. Additional control may be obtained by using a holographic optical element (HOE), constructed to add necessary compensating aberrations. Details of the best configuration and the limitations of performance are presented.

  1. MODIS: Moderate-resolution imaging spectrometer. Earth observing system, volume 2B

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The Moderate-Resolution Imaging Spectrometer (MODIS), as presently conceived, is a system of two imaging spectroradiometer components designed for the widest possible applicability to research tasks that require long-term (5 to 10 years), low-resolution (52 channels between 0.4 and 12.0 micrometers) data sets. The system described is preliminary and subject to scientific and technological review and modification, and it is anticipated that both will occur prior to selection of a final system configuration; however, the basic concept outlined is likely to remain unchanged.

  2. Development of a portable preconcentrator/ion mobility spectrometer system for the trace detection of narcotics

    SciTech Connect

    Parmeter, J.E.; Custer, C.A.

    1997-08-01

    This project was supported by LDRD funding for the development and preliminary testing of a portable narcotics detection system. The system developed combines a commercial trace detector known as an ion mobility spectrometer (IMS) with a preconcentrator originally designed by Department 5848 for the collection of explosives molecules. The detector and preconcentrator were combined along with all necessary accessories onto a push cart, thus yielding a fully portable detection unit. Preliminary testing with both explosives and narcotics molecules shown that the system is operational, and that it can successfully detect drugs as marijuana, methamphetamine (speed), and cocaine based on their characteristics IMS signatures.

  3. A CDU-based data acquisition system for the energy spectrometer at the Stanford Linear Collider

    SciTech Connect

    Briggs, D.D.; Tinsman, J.E.; Rouse, F.; von Zanthier, C.

    1988-10-01

    We describe a system using the Calorimetry Data Unit (a 32-channel multisample analog integrated circuit) to read out the charge ejected by secondary emission of a synchrotron beam from wires lying in its path. The wires comprise the Wire-Imaging Synchrotron Radiation Detector (WISRD) in the SLC Extraction-Line Spectrometer. The primary module in the system is a board containing 24 channels of charge sensitive amplification, shaping, sampling, multiplexing and digitization. This board also provides a fast analog measure of the charge distribution across the wires. We discuss the design and performance of this system. 4 refs., 5 figs.

  4. Comparisons between digital gamma-ray spectrometer (DSPec) and standard nuclear instrumentation methods (NIM) systems

    SciTech Connect

    Vo, D.T.; Russo, P.A.; Sampson, T.E.

    1998-03-01

    Safeguards isotopic measurements require the best spectrometer systems with excellent resolution, stability and throughput. Up until about a year ago, gamma ray spectroscopy has always been done using the analog amplifier, which processes the pulses from the preamplifier to remove the noise, reject the pile up signals, and shape the signals into some desirable form before sending them to the analog to digital converter (ADC) to be digitized. In late 1996, EG and G Ortec introduced a digital gamma ray spectrometer (DSPec) which uses digital technology to analyze the preamplifiers` pulses from all types of germanium and silicon detectors. Considering its performance, digital based spectroscopy may become the way of future gamma ray spectroscopy.

  5. System Analysis on Absorption Chiller Utilizing Intermediate Wasted Heat

    NASA Astrophysics Data System (ADS)

    Yamada, Miki; Suzuki, Hiroshi; Usui, Hiromoto

    A system analysis has been performed for the multi-effect absorption chiller (MEAC) applied as a bottoming system of 30kW class hybrid system including micro gas turbine (MGT) and solid oxide fuel cell (SOFC) hybrid system. In this paper, an intermediate wasted heat utilization (IWHU) system is suggested for lifting up the energy efficiency of the whole system and coefficient of performance (COP) of MEAC. From the results, the suggested IWHU system was found to show the very high energy efficiency compared with a terminal wasted heat utilization (TWHU) system that uses only the heat exhausted from the terminal of MGT/SOFC system. When TWHU system is applied for MEAC, the utilized heat from the MGT/SOFC system is found to remain low because the temperature difference between the high temperature generator and the wasted heat becomes small. Then, the energy efficiency does not become high in spite of high COP of MEAC. On the other hand, the IWHU system could increase the utilized heat for MEAC as performs effectively. The exergy efficiency of IWHU system is also revealed to be higher than that of a direct gas burning system of MEAC, because the wasted heat is effectively utilized in the IWHU system.

  6. The research of digital circuit system for high accuracy CCD of portable Raman spectrometer

    NASA Astrophysics Data System (ADS)

    Yin, Yu; Cui, Yongsheng; Zhang, Xiuda; Yan, Huimin

    2013-08-01

    double sampler; a digitally controlled variable gain amplifier and a 16-bit A/D converter which can help improve the data quality. And the acquired digital signals are transmitted into the computer via USB 2.0 data port. Our spectrometer with SHINERS technology can acquire the Raman spectrum signals efficiently in long time integration and weak signal environment, and the size of our system is well controlled for portable application.

  7. Vegetation species composition and canopy architecture information expressed in leaf water absorption measured in the 1000 nm and 2200 spectral region by an imaging spectrometer

    NASA Technical Reports Server (NTRS)

    Green, Robert O.; Roberts, Dar A.

    1995-01-01

    Plant species composition and plant architectural attributes are critical parameters required for the measuring, monitoring, and modeling of terrestrial ecosystems. Remote sensing is commonly cited as an important tool for deriving vegetation properties at an appropriate scale for ecosystem studies, ranging from local to regional and even synoptic scales. Classical approaches rely on vegetation indices such as the normalized difference vegetation index (NDVI) to estimate biophysical parameters such as leaf area index or intercepted photosynthetically active radiation (IPAR). Another approach is to apply a variety of classification schemes to map vegetation and thus extrapolate fine-scale information about specific sites to larger areas of similar composition. Imaging spectrometry provides additional information that is not obtainable through broad-band sensors and that may provide improved inputs both to direct biophysical estimates as well as classification schemes. Some of this capability has been demonstrated through improved discrimination of vegetation, estimates of canopy biochemistry, and liquid water estimates from vegetation. We investigate further the potential of leaf water absorption estimated from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data as a means for discriminating vegetation types and deriving canopy architectural information. We expand our analysis to incorporate liquid water estimates from two spectral regions, the 1000-nm region and the 2200-nm region. The study was conducted in the vicinity of Jasper Ridge, California, which is located on the San Francisco peninsula to the west of the Stanford University campus. AVIRIS data were acquired over Jasper Ridge, CA, on June 2, 1992, at 19:31 UTC. Spectra from three sites in this image were analyzed. These data are from an area of healthy grass, oak woodland, and redwood forest, respectively. For these analyses, the AVIRIS-measured upwelling radiance spectra for the entire Jasper

  8. Infrared absorption of gaseous benzoyl radical C6H5CO recorded with a step-scan Fourier-transform spectrometer.

    PubMed

    Lin, Shu-Yu; Lee, Yuan-Pern

    2012-06-21

    A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the gaseous transient species benzoyl radical, C(6)H(5)CO. C(6)H(5)CO was produced either from photolysis of acetophenone, C(6)H(5)C(O)CH(3), at 248 nm or in reactions of phenyl radical (C(6)H(5)) with CO; C(6)H(5) was produced on photolysis of C(6)H(5)Br at 248 nm. One intense band at 1838 ± 1 cm(-1), one weak band at 1131 ± 3 cm(-1), and two extremely weak bands at 1438 ± 5 and 1590 ± 10 cm(-1) are assigned to the C═O stretching (ν(6)), the C-C stretching mixed with C-H deformation (ν(15)), the out-of-phase C(1)C(2)C(3)/C(5)C(6)C(1) symmetric stretching (ν(10)), and the in-phase C(1)C(2)C(3)/C(4)C(5)C(6) antisymmetric stretching (ν(7)) modes of C(6)H(5)CO, respectively. These observed vibrational wavenumbers and relative IR intensities agree with those reported for C(6)H(5)CO isolated in solid Ar and with values predicted for C(6)H(5)CO with the B3LYP/aug-cc-pVDZ method. The rotational contours of the two bands near 1838 and 1131 cm(-1) simulated according to rotational parameters predicted with the B3LYP/aug-cc-pVDZ method fit satisfactorily with the experimental results. Additional products BrCO, C(6)H(5)C(O)Br, and C(6)H(5)C(O)C(6)H(5) were identified in the C(6)H(5)Br/CO/N(2) experiments; the kinetics involving C(6)H(5)CO and C(6)H(5)C(O)Br are discussed. PMID:22369517

  9. Absolute intensity calibration of the Wendelstein 7-X high efficiency extreme ultraviolet overview spectrometer system

    NASA Astrophysics Data System (ADS)

    Greiche, Albert; Biel, Wolfgang; Marchuk, Oleksandr; Burhenn, Rainer

    2008-09-01

    The new high effiency extreme ultraviolet overview spectrometer (HEXOS) system for the stellarator Wendelstein 7-X is now mounted for testing and adjustment at the tokamak experiment for technology oriented research (TEXTOR). One part of the testing phase was the intensity calibration of the two double spectrometers which in total cover a spectral range from 2.5 to 160.0 nm with overlap. This work presents the current intensity calibration curves for HEXOS and describes the method of calibration. The calibration was implemented with calibrated lines of a hollow cathode light source and the branching ratio technique. The hollow cathode light source provides calibrated lines from 16 up to 147 nm. We could extend the calibrated region in the spectrometers down to 2.8 nm by using the branching line pairs emitted by an uncalibrated pinch extreme ultraviolet light source as well as emission lines from boron and carbon in TEXTOR plasmas. In total HEXOS is calibrated from 2.8 up to 147 nm, which covers most of the observable wavelength region. The approximate density of carbon in the range of the minor radius from 18 to 35 cm in a TEXTOR plasma determined by simulating calibrated vacuum ultraviolet emission lines with a transport code was 5.5×1017 m-3 which corresponds to a local carbon concentration of 2%.

  10. A Gas Chromatograph/Mass Spectrometer System for UltraLow-Emission Combustor Exhaust Studies

    NASA Technical Reports Server (NTRS)

    Brabbs, Theodore A.; Wey, Chowen Chou

    1996-01-01

    A gas chromatograph (GC)/mass spectrometer (MS) system that allows the speciation of unburnt hydrocarbons in the combustor exhaust has been developed at the NASA Lewis Research Center. Combustion gas samples are withdrawn through a water-cooled sampling probe which, when not in use, is protected from contamination by a high-pressure nitrogen purge. The sample line and its connecting lines, filters, and valves are all ultraclean and are heated to avoid condensation. The system has resolution to the parts-per-billion (ppb) level.

  11. SWEPP gamma-ray spectrometer system software user`s guide

    SciTech Connect

    Femec, D.A.

    1994-08-01

    The SWEPP Gamma-Ray Spectrometer (SGRS) System has been developed by the Radiation Measurement and Development Unit of the Idaho National Engineering Laboratory to assist in the characterization of the radiological contents of contact-handled waste containers at the Stored Waste Examination Pilot Plant (SWEPP). In addition to determining the concentrations of gamma-ray-emitting radionuclides, the software also calculates attenuation-corrected isotopic mass ratios of specific interest, and provides controls for SGRS hardware as required. This document serves as a user`s guide for the data acquisition and analysis software associated with the SGRS system.

  12. Toward a Micro Gas Chromatograph/Mass Spectrometer (GC/MS) System

    NASA Astrophysics Data System (ADS)

    Wiberg, D. V.; Eyre, F. B.; Orient, O.; Chutjian, A.; Garkarian, V.

    2001-01-01

    Miniature mass filters (e.g., quadrupoles, ion traps) have been the subject of several miniaturization efforts. A project is currently in progress at JPL to develop a miniaturized Gas Chromatograph/Mass Spectrometer (GC/MS) system, incorporating and/or developing miniature system components including turbomolecular pumps, scroll type roughing pump, quadrupole mass filter, gas chromatograph, precision power supply and other electronic components. The preponderance of the system elements will be fabricated using microelectromechanical systems (MEMS) techniques. The quadrupole mass filter will be fabricated using an X-ray lithography technique producing high precision, 5x5 arrays of quadrupoles with pole lengths of about 3 mm and a total volume of 27 cubic mm. The miniature scroll pump will also be fabricated using X-ray lithography producing arrays of scroll stages about 3 mm in diameter. The target detection range for the mass spectrometer is 1 to 300 atomic mass units (AMU) with are solution of 0.5 AMU. This resolution will allow isotopic characterization for geochronology, atmospheric studies and other science efforts dependant on the understanding of isotope ratios of chemical species. This paper will discuss the design approach, the current state-of-the art regarding the system components and the progress toward development of key elements. The full system is anticipated to be small enough in mass, volume and power consumption to allow in situ chemical analysis on highly miniaturized science craft for geochronology, atmospheric characterization and detection of life experiments applicable to outer planet roadmap missions.

  13. Mid-infrared laser absorption spectrometers based upon all-diode laser difference frequency generation and a room temperature quantum cascade laser for the detection of CO, N2O and NO

    NASA Astrophysics Data System (ADS)

    Kasyutich, V. L.; Holdsworth, R. J.; Martin, P. A.

    2008-08-01

    We describe the performance of two mid-infrared laser spectrometers for carbon monoxide, nitrous oxide and nitric oxide detection. The first spectrometer for CO and N2O detection around 2203 cm-1 is based upon all-diode laser difference frequency generation (DFG) in a quasi-phase matched periodically-poled lithium niobate (PPLN) crystal using two continuous-wave room-temperature distributed feedback diode lasers at 859 and 1059 nm. We also report on the performance of a mid-infrared spectrometer for NO detection at ˜ 1900 cm-1 based upon a thermoelectrically-cooled continuous-wave distributed feedback quantum cascade laser (QCL). Both spectrometers had a single-pass optical cell and a thermoelectrically cooled HgCdZnTe photovoltaic detector. Typical minimum detection limits of 2.8 ppmv for CO, 0.6 ppmv for N2O and 2.7 ppmv for NO have been demonstrated for a 100 averaged spectra acquired within 1.25 s and a cell base length of 21 cm at ˜ 100 Torr. Noise-equivalent absorptions of 10-5 and 10-4 Hz-1/2 are typically demonstrated for the QCL and the DFG based spectrometers, respectively.

  14. Tunable Optomechanically Induced Absorption in a Hybrid Optomechanical System

    NASA Astrophysics Data System (ADS)

    Wang, Qiong; Zhao, Yun-Hui; He, Zhi; Yao, Chun-Mei

    2016-03-01

    We study the tunable optomechanically induced absorption (OMIA) with the quantized field in the system, which consists of a driven cavity and a mechanical resonator with a super-conducting charge qubit via Jaynes-Cummings interaction. Such a OMIA can be achieved by controlling the strength of the Jaynes-Cummings interaction. Moreover, our work shows this OMIA for the quantized fields can be robust against cavity decay in somehow. With the combination of optomechanically induced transparency (OMIT), our proposal may have paved a new avenue towards quantum photon router.

  15. First Detection of HCO+ Absorption in the Magellanic System

    NASA Astrophysics Data System (ADS)

    Murray, Claire E.; Stanimir´, Snežana; McClure-Griffiths, N. M.; Putman, M. E.; Liszt, H. S.; Wong, Tony; Richter, P.; Dawson, J. R.; Dickey, John M.; Lindner, Robert R.; Babler, Brian L.; Allison, J. R.

    2015-07-01

    We present the first detection of HCO+ absorption in the Magellanic System. Using the ATCA, we observed nine extragalactic radio continuum sources behind the Magellanic System and detected HCO+ absorption toward one source located behind the leading edge of the Magellanic Bridge. The detection is located at an LSR velocity of v=214.0+/- 0.4 {km} {{{s}}}-1, with an FWHM of {{Δ }}v=4.5+/- 1.0 {km} {{{s}}}-1, and an optical depth of τ ({{HCO}}+)=0.10+/- 0.02. Although there is abundant neutral hydrogen (H i) surrounding the sight line in position-velocity space, at the exact location of the absorber the H i column density is low, \\lt {10}20 {{cm}}-2, and there is little evidence for dust or CO emission from Planck observations. While the origin and survival of molecules in such a diffuse environment remain unclear, dynamical events such as H i flows and cloud collisions in this interacting system likely play an important role.

  16. Performance analysis of solar powered absorption refrigeration system

    NASA Astrophysics Data System (ADS)

    Abu-Ein, Suleiman Qaseem; Fayyad, Sayel M.; Momani, Waleed; Al-Bousoul, Mamdouh

    2009-12-01

    The present work provides a detailed thermodynamic analysis of a 10 kW solar absorption refrigeration system using ammonia-water mixtures as a working medium. This analysis includes both first law and second law of thermodynamics. The coefficient of performance (COP), exergetic coefficient of performance (ECOP) and the exergy losses (Δ E) through each component of the system at different operating conditions are obtained. The minimum and maximum values of COP and ECOP were found to be at 110 and 200°C generator temperatures respectively. About 40% of the system exergy losses were found to be in the generator. The maximum exergy losses in the absorber occur at generator temperature of 130°C for all evaporator temperatures. A computer simulation model is developed to carry out the calculations and to obtain the results of the present study.

  17. Pulsed laser linescanner for a backscatter absorption gas imaging system

    DOEpatents

    Kulp, Thomas J.; Reichardt, Thomas A.; Schmitt, Randal L.; Bambha, Ray P.

    2004-02-10

    An active (laser-illuminated) imaging system is described that is suitable for use in backscatter absorption gas imaging (BAGI). A BAGI imager operates by imaging a scene as it is illuminated with radiation that is absorbed by the gas to be detected. Gases become "visible" in the image when they attenuate the illumination creating a shadow in the image. This disclosure describes a BAGI imager that operates in a linescanned manner using a high repetition rate pulsed laser as its illumination source. The format of this system allows differential imaging, in which the scene is illuminated with light at least 2 wavelengths--one or more absorbed by the gas and one or more not absorbed. The system is designed to accomplish imaging in a manner that is insensitive to motion of the camera, so that it can be held in the hand of an operator or operated from a moving vehicle.

  18. Evolution of high-redshift Lyman-limit absorption systems

    SciTech Connect

    Lanzetta, K.M. )

    1991-07-01

    Results are presented of a new spectroscopic survey of high-redshift Lyman-limit absorption systems. Based on this data set, the rate of incidence of the Lyman-limit systems with z greater than about 2.5 is found to evolve strongly with redshift in the sense that the product of the number density per unit comoving volume and the absorption cross section increases with increasing redshift. If the observed evolution indicates intrinsic evolution of the absorbers, this result suggests that the evolution detected previously for the C IV-selected absorbers over a similar redshift range is not naturally interpreted as evolution of the ionization level of the absorbers rather than as a chemical enrichment effect. The data are also used to investigate the H I column density distribution and to examine the multiple-component structure of the absorbing complexes. The H I column density distribution is found to be well fitted by a power-law form. 35 refs.

  19. INTERSTELLAR SILICATE DUST IN FIVE QUASAR ABSORPTION SYSTEMS

    SciTech Connect

    Kulkarni, Varsha P.; Torres-Garcia, Legna M.; Som, Debopam; York, Donald G.; Welty, Daniel E.; Vladilo, Giovanni

    2011-01-01

    We report on a study of interstellar silicate dust in five quasar absorption systems at 0.44 < z{sub abs} < 1.31 toward quasars Q0235+164, 3C196, Q0852+3435, Q0937+5628, and Q1203+0634, using data from the Infrared Spectrograph on board the Spitzer Space Telescope. In the absorbers toward Q0235+164, 3C196, Q0852+3435, and Q0937+5628, the 9.7 {mu}m silicate feature is detected in absorption at {approx}5{sigma}-10{sigma} significance, with rest-frame equivalent widths of {approx}0.2-0.5 {mu}m. For Q1203+0634, the noisy data allow us to make only a 3.6{sigma} detection of absorption at 10 {mu}m. Fits to the redshifted 9.7 {mu}m features with four possible template profiles indicate that the laboratory amorphous olivine profile generally provides the best fit, with inferred peak optical depths of {tau}{sub 9.7} {approx} 0.08-0.18. For three of the quasars with optical spectra available from the Sloan Digital Sky Survey, the Large Magellanic Cloud supershell extinction curve provides the best formal fits, with E(B - V) of 0.34-0.54 mag. A 2175 A extinction bump at the absorber redshift (known to exist in Q0235+164) appears to be present at >2.8{sigma} level in Q0852+3435, >2.5{sigma} level in Q1203+0634, and marginally at nearly 2{sigma} level in Q0937+5628. We briefly explore possible correlations between {tau}{sub 9.7} and the color excess, the strength of the 2175 A bump, and the metallicity (which appears to be relatively high for these absorbers, in the range of {approx}>0.1 solar to supersolar). While our measurements are consistent with a linear relation between {tau}{sub 9.7} and E(B - V), the {tau}{sub 9.7}/E(B - V) ratios for these quasar absorbers appear to be higher than those for diffuse interstellar clouds in the Milky Way, closer to values observed for the Galactic center. Some of these quasar sightlines may trace regions in the bulges of the galaxies responsible for the absorption systems.

  20. An Intelligent Dynamic Alignment System for Interferometer of Fourier Transform Spectrometer

    NASA Astrophysics Data System (ADS)

    Yang, Kun; Zeng, Libo

    An intelligent dynamic alignment system for a Michelson interferometer which is applied to a Mid-infrared band Fourier transform spectrometer (FTS) is presented. Three photodiodes are used to detect the tilt of moving mirror opposite to fixed mirror with the assistance of the interfered signal of a reference He-Ne laser. This technique is based on detecting the phase difference of laser signal between every two diodes in two perpendicular directions. And four magnetic actuators behind the mounting brace of fixed mirror are used to change the pose of fixed mirror. The system is controlled by a digital signal processor (DSP) in real-time. A feedback algorithm is used to tilt fixed mirror following the action of moving mirror so as to keep both mirror planes in perpendicular. Experiment result shows that the relative tilt between two reflecting mirrors can be restricted in a range no more than ±1.5×10-6rad. This system is effective and reliable to be applied to scanning interferometer of Fourier transform spectrometer.

  1. Balloon-borne ultraviolet stellar spectrometer: Acquisition, tracking and command systems

    NASA Technical Reports Server (NTRS)

    Gibson, W. C.

    1974-01-01

    The NASA Balloon-borne Ultraviolet Stellar Spectrometer (BUSS) which is carried to an altitude of 40 km by a 15 million cubic foot balloon for night-time observations of ultraviolet stellar spectra is discussed. The BUSS optical system, comprising an 0.40 m aperture Cassegrain telescope and an Ebert-Fastie spectrometer, points at various selected stars and focuses a portion of their spectra on the photocathode of an image dissector tube. The spectral region between 2,775 Angstroms and 2,825 Angstroms is sampled by the detector at 0.25 Angstroms increments using photon counting techniques. The pointing system for the payload uses a pair of orthogonal magnetometers which sense the earth's magnetic field for an aximuth reference, and a platform potentiometer for an elevation reference. This pointing system places the target star within the 3x1 degree field of view of an outer optical star tracker. The outer star tracker is then used to point the entire instrument to within one arc minute of the target star.

  2. Evaluation of absorption cycle for space station environmental control system application

    NASA Technical Reports Server (NTRS)

    Sims, W. H.; Oneill, M. J.; Reid, H. C.; Bisenius, P. M.

    1972-01-01

    The study to evaluate an absorption cycle refrigeration system to provide environmental control for the space stations is reported. A zero-gravity liquid/vapor separator was designed and tested. The results were used to design a light-weight, efficient generator for the absorption refrigeration system. It is concluded that absorption cycle refrigeration is feasible for providing space station environmental control.

  3. Tropospheric Emission Spectrometer and Airborne Emission Spectrometer

    NASA Technical Reports Server (NTRS)

    Glavich, T.; Beer, R.

    1996-01-01

    The Tropospheric Emission Spectrometer (TES) is an instrument being developed for the NASA Earth Observing System Chemistry Platform. TES will measure the distribution of ozone and its precursors in the lower atmosphere. The Airborne Emission Spectrometer (AES) is an aircraft precursor to TES. Applicable descriptions are given of instrument design, technology challenges, implementation and operations for both.

  4. A multi-channel monolithic Ge detector system for fluorescence x-ray absorption spectroscopy

    SciTech Connect

    Bucher, J.J.; Allen, P.G.; Edelstein, N.M.; Shuh, D.K.; Madden, N.W.; Cork, C.; Luke, P.; Pehl, D.; Malone, D.

    1995-03-01

    Construction and performance of a monolithic quad-pixel Ge detector for fluorescence x-ray absorption spectroscopy (XAS) at synchrotron radiation sources are described. The detector semiconductor element has an active surface area of 4.0 cm{sup 2} which is electrically separated into four 1.0 cm{sup 2} pixels, with little interfacial dead volume. Spatial response of the array shows that cross-talk between adjacent pixels is < 10% for 5.9 keV photons that fall within 0.5 mm of the pixel boundaries. The detector electronics system uses pre-amplifiers built at LBNL with commercial Tennelec Model TC 244 amplifiers. Using an {sup 55}Fe test source (MnK{sub {alpha}}, 5.9 keV), energy resolution of better than 200 eV is achieved with a 4 {mu}sec peaking time. At 0.5 {mu}sec peaking time, pulse pileup results in a 75% throughput efficiency for an incoming count rate of 100 kHz. Initial XAS fluoresncece measurements at the beamline 4 wiggler end stations at SSRL show that the detector system has several advantages over commercial x-ray spectrometers for low-concentration counting.

  5. Networking mass spectrometer data systems for improved productivity and electronic archiving of data.

    PubMed

    Hayward, M J; Robandt, P V; Meek, J T; Thomson, M L

    1993-09-01

    Several Finngan-MAT mass spectrometer data systems were networked together to achieve the following two primary objectives: (1) to allow access to mass spectrometry data and data processing functions from remote locations without affecting simultaneous data acquisition at the instruments, and (2) to electronically archive mass spectrometry data at a central location on a high-capacity, fast-access device that allows rapid retrieval of archived data for all data processing operations at all locations. UNIX workstations, IBM PC/AT-compatible computers, and Data General Nova minicomputers were connected via Ethernet interfaces to allow rapid data transfer among all systems as well as X-Windows access to UNIX-based systems. Bridging techniques were used to isolate possible high-traffic areas of the network and to enable security measures for adequate protection of files. Additionally, serial connections were made through a Northern Telecom phone system to provide remote terminal access to the Data General Nova-based systems. Use of these connectivity techniques significantly improved productivity by allowing retrieval, processing, and printing of data from remote locations, such as office areas, without affecting data acquisition, processing, and printing performed simultaneously at the instruments. For archival purposes, data files are electronically stored on high-capacity magneto-optical disks for rapid retrieval. A highcapacity fixed disk is also available for centralized temporary data file storage. A Digital Equipment Corporation DECstation 2100 UNIX workstation was used as the file server for centralized data storage while being simultaneously utilized as the data system computer for one of the mass spectrometers. Utilization of this UNIX-based file server system in conjunction with Ethernet connectivity techniques provides a centralized, rapid-access, high-capacity, cost- and space-efficient method for electronic archival of mass spectrometry raw data recorded

  6. The Super Separator Spectrometer S3 and the associated detection systems: SIRIUS & LEB-REGLIS3

    NASA Astrophysics Data System (ADS)

    Déchery, F.; Savajols, H.; Authier, M.; Drouart, A.; Nolen, J.; Ackermann, D.; Amthor, A. M.; Bastin, B.; Berryhill, A.; Boutin, D.; Caceres, L.; Coffey, M.; Delferrière, O.; Dorvaux, O.; Gall, B.; Hauschild, K.; Hue, A.; Jacquot, B.; Karkour, N.; Laune, B.; Le Blanc, F.; Lecesne, N.; Lopez-Martens, A.; Lutton, F.; Manikonda, S.; Meinke, R.; Olivier, G.; Payet, J.; Piot, J.; Pochon, O.; Prince, V.; Souli, M.; Stelzer, G.; Stodel, C.; Stodel, M.-H.; Sulignano, B.; Traykov, E.; Uriot, D.

    2016-06-01

    The Super Separator Spectrometer (S3) facility is developed in the framework of the SPIRAL2 project [1]. S3 has been designed to extend the capability of the facility to perform experiments with extremely low cross sections, taking advantage of the very high intensity stable beams of the superconducting linear accelerator of SPIRAL2. It will mainly use fusion-evaporation reactions to reach extreme regions of the nuclear chart: new opportunities will be opened for super-heavy element studies and spectroscopy at and beyond the driplines. In addition to our previous article (Déchery et al. [2]) introducing the optical layout of the spectrometer and the expected performances, this article will present the current status of the main elements of the facility: the target station, the superconducting multipole, and the magnetic and electric dipoles, with a special emphasis on the status of the detection system SIRIUS and on the low-energy branch which includes the REGLIS3 system. S3 will also be a source of low energy radioactive isotopes for delivery to the DESIR facility.

  7. Thermal monitoring: Raman spectrometer system for remote measurement of cellular temperature on a microscopic scale.

    PubMed

    Pikov, Victor; Siegel, Peter H

    2010-01-01

    A simple setup is demonstrated for remote temperature monitoring of water, water-based media, and cells on a microscopic scale. The technique relies on recording changes in the shape of a stretching band of the hydroxyl group in liquid water at 3,100-3,700 cm(-1). Rather than direct measurements in the near-infrared (IR), a simple Raman spectrometer setup is realized. The measured Raman shifts are observed at near optical wavelengths using an inverted microscope with standard objectives in contrast to costly near-IR elements. This allows for simultaneous visible inspection through the same optical path. An inexpensive 671-nm diode pump laser (< 100 mW), standard dichroic and lowpass filters, and a commercial 600-1,000 nm spectrometer complete the instrument. Temperature changes of 1 degrees C are readily distinguished over a range consistent with cellular processes (25-45 degrees C) using integration times below 10 s. Greatly improved sensitivity was obtained by an automated two-peak fitting procedure. When combined with an optical camera, the instrument can be used to monitor changes in cell behavior as a function of temperature without the need for invasive probing. The instrument is very simple to realize, inexpensive compared with traditional Raman spectrometers and IR microscopes, and applicable to a wide range of problems in microthermometry of biological systems. In a first application of its kind, the instrument was used to successfully determine the temperature rise of a cluster of H1299 derived human lung cells adhered to polystyrene and immersed in phosphate-buffered saline (PBS) under exposure of RF millimeter wave radiation (60 GHz, 1.3, 2.6, and 5.2 mW/mm2). PMID:20176524

  8. Absorption heat pump in heating and cooling systems of buildings

    NASA Astrophysics Data System (ADS)

    Aho, I.

    This report focuses on the operation and applicability of absorption heat pumps (AHP) in building heating and cooling systems. Examples are presented on heating systems of residential buildings and a heating/cooling system of an office building. Despite the limitations of present AHP technology the examples assume AHPs which produce heat at an appropriate temperature level for each application. According to the calculations the primary energy saving potential of AHPs in building specific heat production is 20 to 40 percent. For AHPs coupled with district heating systems the primary energy saving potential can not be unambiguously defined because it is influenced by the production form of district heat, the influence of district heat demand on power generation etc. For the time being economical aspects limit the application potential of AHPs. The profitability of AHP investments is quite poor because of present energy prices, the price ratio of different energy forms and the high investment cost of AHP-systems. The environmental impact of AHPs depend on the fuel used in the generator. Using fuel oil or gas will decrease sulphur and particle emissions but might increase the emissions of NO(x) and hydrocarbons because of the smaller size of combustion units. CFC-emissions will be decreased because AHPs apply alternative refrigerants.

  9. Mass-spectrometer-based continuous emissions monitoring system for acid-gas emissions and DRE demonstration

    NASA Astrophysics Data System (ADS)

    Bartman, Candace D.; Connolly, Erin; Renfroe, Jim; Harlow, George

    1993-03-01

    The objective of the work presented here was to develop a technology for continuous measurement of stack gas emissions for compounds such as HCl, SO2, and NOx that was also capable of monitoring toxic hydrocarbons. The goal was to assure operators and local communities that the emission source is routinely operating in compliance with and well within the U.S. Environmental Protection Agency guidelines. A mass spectrometer-based continuous emissions monitoring system (CEMS) and its sample extraction system developed as a result of this work are described. Results of calibration drift, linearity, and accuracy tests for HCl, SO2, and NOx are presented. Results of CEMS tests are described that show the system has the performance capabilities necessary for a relatively inexpensive and frequent DRE demonstration.

  10. Gain stabilization control system of the upgraded magnetic proton recoil neutron spectrometer at JET

    SciTech Connect

    Sjoestrand, Henrik; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Ronchi, E.; Weiszflog, M.; Gorini, G.; Tardocchi, M.; Popovichev, S. [EURATOM Collaboration: JET EFDA Contributors

    2009-06-15

    Burning plasma experiments such as ITER and DEMO require diagnostics capable of withstanding the harsh environment generated by the intense neutron flux and to maintain stable operating conditions for times longer than present day systems. For these reasons, advanced control and monitoring (CM) systems will be necessary for the reliable operation of diagnostics. This paper describes the CM system of the upgraded magnetic proton recoil neutron spectrometer installed at the Joint European Torus focusing in particular on a technique for the stabilization of the gain of the photomultipliers coupled to the neutron detectors. The results presented here show that this technique provides good results over long time scales. The technique is of general interest for all diagnostics that employ scintillators coupled to photomultiplier tubes.

  11. Innovative Gamma Ray Spectrometer Detection Systems for Conducting Scanning Surveys on Challenging Terrain - 13583

    SciTech Connect

    Palladino, Carl; Mason, Bryan; Engle, Matt; LeVangie, James; Dempsey, Gregg; Klemovich, Ron

    2013-07-01

    The Santa Susana Field Laboratory located near Simi Valley, California was investigated to determine the nature and extent of gamma radiation anomalies. The primary objective was to conduct gamma scanning surveys over 100 percent of the approximately 1,906,000 square meters (471 acre) project site with the most sensitive detection system possible. The site had challenging topography that was not conducive to traditional gamma scanning detection systems. Terrain slope varied from horizontal to 48 degrees and the ground surface ranged from flat, grassy meadows to steep, rocky hillsides. In addition, the site was home to many protected endangered plant and animal species, and archaeologically significant sites that required minimal to no disturbance of the ground surface. Therefore, four innovative and unique gamma ray spectrometer detection systems were designed and constructed to successfully conduct gamma scanning surveys of approximately 1,076,000 square meters (266 acres) of the site. (authors)

  12. Evaluation of a FTIR (Fourier Transform Infrared Spectrometer) mobile source measurement system

    NASA Astrophysics Data System (ADS)

    Sigsby, John E., Jr.; McArver, Alex; Snow, Richard

    1989-04-01

    An initial evaluation was made of a prototype Fourier transform infrared spectrometer on its ability to measure mobile source emissions. This prototype represents the commercialization of research technology developed by the Ford Motor Co. The system utilizes a Mattson Instruments Co. interferometer coupled to a Masscomp computer. The required software is still incomplete. This has resulted in the inability to correct errors or optimize results. Unreliability of both hardware and software is a major shortcoming of the system. When operating properly, the system measures carbon dioxide, nitric oxide, and formaldehyde accurately, both when compared to bag analysis and on direct point-by-point comparisons with real-time data. Completion of the evaluation awaits the final software translations and improvements in reliability.

  13. Optical performance and metallic absorption in nanoplasmonic systems.

    PubMed

    Arnold, Matthew D; Blaber, Martin G

    2009-03-01

    Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges. PMID:19259225

  14. Application of a long-path differential optical absorption spectrometer (LP-DOAS) on the measurements of NO(2), SO(2), O(3), and HNO(2) in Gwangju, Korea.

    PubMed

    Lee, Jeongsoon; Kim, Ki-Hyun; Kim, Young J; Lee, Jaihoon

    2008-03-01

    A differential optical absorption spectrometer (DOAS) technique has been applied to monitor airborne trace pollutants including NO(2), SO(2), O(3), and HNO(2) in the ultraviolet (UV) region (290-350 nm) over a 1.5 km beam path (two ways) during an intensive measurement campaign held at Gwangju, Korea (March 2002). Their mean mixing ratios (and standard deviations) were computed as 11.3 (8.8), 1.9 (1.7), 17.1 (19.3), and 0.5 (0.4)ppbv, respectively. As a means to evaluate the performance of the long-path DOAS (LP-DOAS) system with conventional point monitoring systems (PMS), correlation analysis was conducted between the two data sets. These data sets were then inspected to account for the influence of the environmental conditions on the correlation strength between the two systems, especially with respect to light level and wind speed. To facilitate the comparison, correlation analyses were conducted after dividing the data sets for those parameters into several classes. The strength of the correlations between DOAS and meteorological parameters was also examined to evaluate their effects on the DOAS performance. It was found that, among the four pollutant species, O(3) is the most sensitive to changes in meteorological conditions in relation with atmospheric mixing conditions. The overall results of our study indicate that open-path monitoring techniques can be used to effectively diagnose air quality and be substituted for the conventional point monitoring methods with the proper consideration of those parameters affecting the DOAS sensitivity (e.g., light level and wind speed). PMID:17335958

  15. A Vacuum Ultraviolet Absorption Array Spectrometer as a Selective Detector for Comprehensive Two-Dimensional Gas Chromatography: Concept and First Results.

    PubMed

    Gröger, Thomas; Gruber, Beate; Harrison, Dale; Saraji-Bozorgzad, Mohammad; Mthembu, Makhosazana; Sutherland, Aimée; Zimmermann, Ralf

    2016-03-15

    Fast and selective detectors are very interesting for comprehensive two-dimensional gas chromatography (GC × GC). This is particularly true if the detector system can provide additional spectroscopic information on the compound structure and/or functionality. Other than mass spectrometry (MS), only optical spectroscopic detectors are able to provide selective spectral information. However, until present the application of optical spectroscopy technologies as universal detectors for GC × GC has been restricted mainly due to physical limitations such as insufficient acquisition speed or high detection limits. A recently developed simultaneous-detection spectrometer working in the vacuum ultraviolet (VUV) region of 125-240 nm overcomes these limitations and meets all the criteria of a universal detector for GC × GC. Peak shape and chromatographic resolution is preserved and unique spectral information, complementary to mass spectrometry data, is gained. The power of this detector is quickly recognized as it has the ability to discriminate between isomeric compounds or difficult to separate structurally related isobaric species; thus, it provides additional selectivity. A further promising feature of this detector is the data analysis concept of spectral filtering, which is accomplished by targeting special electronic transitions that allows for a fast screening of GC × GC chromatograms for designated compound classes. PMID:26810390

  16. Simulation of Absorption Systems in Flexible and Modular Form

    1994-09-23

    The computer code has been developed for simulation of absorption systems at steady-state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system''s components. When all the equations have been established, a mathematical solver routine is employed to solve them simultaneously. Property subroutines contained in a separate data base serve to provide thermodynamicmore » properties of the working fluids. The code is user-oriented and requires a relatively simple input containing the given operating conditions and the working fluid at each state point. the user conveys to the computer an image of the cycle by specifying the different components and their interconnections. Based on this information, the program calculates the temperature, flowrate, concentration, pressure and vapor fraction at each state point in the system and the heat duty at each unit, from which the coefficient of performance may be determined. A graphical user-interface is provided to facilitate interactive input and study of the output.« less

  17. Advanced Sine Wave Modulation of Continuous Wave Laser System for Atmospheric CO2 Differential Absorption Measurements

    NASA Technical Reports Server (NTRS)

    Campbell, Joel F.; Lin, Bing; Nehrir, Amin R.

    2014-01-01

    NASA Langley Research Center in collaboration with ITT Exelis have been experimenting with Continuous Wave (CW) laser absorption spectrometer (LAS) as a means of performing atmospheric CO2 column measurements from space to support the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission.Because range resolving Intensity Modulated (IM) CW lidar techniques presented here rely on matched filter correlations, autocorrelation properties without side lobes or other artifacts are highly desirable since the autocorrelation function is critical for the measurements of lidar return powers, laser path lengths, and CO2 column amounts. In this paper modulation techniques are investigated that improve autocorrelation properties. The modulation techniques investigated in this paper include sine waves modulated by maximum length (ML) sequences in various hardware configurations. A CW lidar system using sine waves modulated by ML pseudo random noise codes is described, which uses a time shifting approach to separate channels and make multiple, simultaneous online/offline differential absorption measurements. Unlike the pure ML sequence, this technique is useful in hardware that is band pass filtered as the IM sine wave carrier shifts the main power band. Both amplitude and Phase Shift Keying (PSK) modulated IM carriers are investigated that exibit perfect autocorrelation properties down to one cycle per code bit. In addition, a method is presented to bandwidth limit the ML sequence based on a Gaussian filter implemented in terms of Jacobi theta functions that does not seriously degrade the resolution or introduce side lobes as a means of reducing aliasing and IM carrier bandwidth.

  18. Mössbauer spectrometer as a virtual instrument in the PXI/Compact PCI modular system

    NASA Astrophysics Data System (ADS)

    Pechousek, J.; Mashlan, M.

    2005-07-01

    A new programming method has been used for building a computer-based Mössbauer spectrometer. Data acquisition is realized via two commercially available PXI/Compact-PCI modules or PCI devices which are supported by relevant software drivers. Both modules, the digital oscilloscope NI 5102 and the function generator NI 5401 (National Instruments Inc.), can be used in the PXI or PC standard. The synchronization between the velocity signal generation and the impulse detection is controlled by a RTSI (Real-Time System Integration) bus. A virtual Mössbauer spectrometer is implemented by the graphical programming language called LabVIEW 7 Express. The amplitude selection of impulses from the detector output is realized with an assistance of the Waveform Peak Detection.vi function. The sampling rate of the detector output signal and the frequency of the velocity signal determinate the number of registration channels of measured Mössbauer spectrum. The Mössbauer spectra can be accumulated in the constant or variable velocity modes; moreover, there is a possibility to register gamma-ray spectra in the multichannel analyzer mode.

  19. Application of a trochoidal electron monochromator/mass spectrometer system to the study of environmental chemicals

    SciTech Connect

    Laramee, J.A.; Kocher, C.A.; Deinzer, M.L. )

    1992-10-15

    A trochoidal electron monochromator has been interfaced to a mass spectrometer to perform electron capture negative ion mass spectrometric (ECNIMS) analyses of environmentally relevant chemicals. The kinetic energy of the electron beam can be varied from 0.025 to 30 eV under computer control. No reagent gas is used to moderate the electron energies. An electron energy spread of +/- 0.1 to +/- 0.4 eV full width at half-maximum (fwhm) can readily be obtained at a transmitted current of 2 x 10(-6) A, improving to +/- 0.07 eV at 5 x 10(-7) A. Comparisons of ECNI results from the electron monochromator/mass spectrometer system with those from a standard instrument that uses a moderating gas show similar spectra for heptachlor but not for the s-triazine herbicides, as for example, atrazine. This compound shows numerous adduct ions by standard ECNIMS that are eliminated by using the electron monochromator to generate the mass spectra. Isomeric tetrachlorodibenzo-p-dioxins show distinct differences in the electron energies needed to produce the maximum amount of parent and fragment anions. Multiple resonance states resulting in stable radical anions (M.-) are easily observed for nitrobenzene and for polycyclic aromatic hydrocarbons. Ionic products of dissociative electron capture invariably occur from several resonance states.

  20. A joint model for the emission and absorption properties of damped Lyα absorption systems

    NASA Astrophysics Data System (ADS)

    Barnes, Luke A.; Haehnelt, Martin G.

    2009-07-01

    The recently discovered population of ultra-faint extended line emitters, with fluxes of a few times 10-18ergs-1cm-2 at z ~ 3, can account for the majority of the incidence rate of damped Lyα systems (DLAs) at this redshift if the line emission is interpreted as Lyα. We show here that a model similar to that proposed by Haehnelt, Steinmetz & Rauch (2000), which reproduces the incidence rate and kinematics of DLAs in the context of Λ cold dark matter models for structure formation, also reproduces the size distribution of the new population of faint Lyα emitters for plausible parameters. This lends further support to the interpretation of the emission as Lyα, as well as the identification of the emitters with the hitherto elusive population of DLA host galaxies. The observed incidence rate of DLAs together with the observed space density and size distribution of the emitters suggest a duty cycle of ~0.2-0.4 for the Lyα emission from DLA host galaxies. We further show that Lyα cooling is expected to contribute little to the Lyα emission for the majority of emitters. This leaves centrally concentrated star formation at a rate of a few tenths Msolaryr-1, surrounded by extended Lyα haloes with radii up to 30-50 kpc, as the most plausible explanation for the origin of the emission. Both the luminosity function of Lyα emission and the velocity width distribution of low ionization absorption require that galaxies inside dark matter (DM) haloes with virial velocities <~50-70kms-1 contribute little to the incidence rate of DLAs at z ~ 3, suggesting that energy and momentum input due to star formation efficiently removes gas from these haloes. Galaxies with DM haloes with virial velocities of 100-150kms-1 appear to account for the majority of DLA host galaxies. DLA host galaxies at z ~ 3 should thus become the building blocks of typical present-day galaxies like our Milky Way.

  1. Data acquisition system with pulse height capability for the TOFED time-of-flight neutron spectrometer

    SciTech Connect

    Chen, Z. J.; Peng, X. Y.; Zhang, X.; Du, T. F.; Hu, Z. M.; Cui, Z. Q.; Ge, L. J.; Xie, X. F.; Yuan, X.; Li, X. Q.; Zhang, G. H.; Chen, J. X.; Fan, T. S.; Gorini, G.; Nocente, M.; Tardocchi, M.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    A new time-of-flight neutron spectrometer TOFED has been constructed for installation at Experimental Advanced Superconducting Tokamak. A data acquisition system combining measurements of flight time and energy from the interaction of neutrons with the TOFED scintillators has been developed. The data acquisition system can provide a digitizing resolution better than 1.5% (to be compared with the >10% resolution of the recoil particle energy in the plastic scintillators) and a time resolution <1 ns. At the same time, it is compatible with high count rate event recording, which is an essential feature to investigate phenomena occurring on time scales faster than the slowing down time (≈100 ms) of the beam ions in the plasma. Implications of these results on the TOFED capability to resolve fast ion signatures in the neutron spectrum from EAST plasmas are discussed.

  2. PHAROS: a spectrometer-on-a-chip for digital radiology systems with spectral detection

    NASA Astrophysics Data System (ADS)

    Cadeddu, S.; Caredda, D.; Caria, M.; Lai, A.; Randaccio, P.

    2002-02-01

    When a beam of X-rays crosses an object, its spectrum is modified depending on both the density and effective atomic number of the material. We describe an integrated (VLSI) spectrometer used in a digital radiology system for performing spectral analysis of the detected X-rays. It integrates 16 independent channels and gives seven bits of energy resolution. This permits the distinction between tissues featuring small differences in effective atomic number, e.g. micro-calcifications and fat cysts, which have the same contrast in a normal radiography. The integrated circuit services a row of solid-state detectors that can travel along the specimen in the radiology system in perpendicular directions, so that bi-dimensional images can be recorded. The circuit performs pulse height analysis and stores the spectral distribution of the detected photons. The circuit is described and its performance analyzed.

  3. Germanium determination by flame atomic absorption spectrometry: an increased vapor pressure-chloride generation system.

    PubMed

    Kaya, Murat; Volkan, Mürvet

    2011-03-15

    A new chloride generation system was designed for the direct, sensitive, rapid and accurate determination of the total germanium in complex matrices. It was aimed to improve the detection limit of chloride generation technique by increasing the vapor pressure of germanium tetrachloride (GeCl(4)). In order to do so, a novel joint vapor production and gas-liquid separation unit equipped with a home-made oven was incorporated to an ordinary nitrous oxide-acetylene flame atomic absorption spectrometer. Several variables such as reaction time, temperature and acid concentration have been investigated. The linear range for germanium determination was 0.1-10 ng mL(-1) for 1 mL sampling volume with a detection limit (3s) of 0.01 ng mL(-1). The relative standard deviation (RSD) was 2.4% for nine replicates of a 1 ng mL(-1) germanium solution. The method was validated by the analysis of one non-certified and two certified geochemical reference materials, respectively, CRM GSJ-JR-2 (Rhyolite), and GSJ-JR-1 (Rhyolite), and GBW 07107 (Chinese Rock). Selectivity of the method was investigated for Cd(2+), Co(2+), Cu(2+), Fe(3+), Ga(3+), Hg(2+), Ni(2+), Pb(2+), Sn(2+), and Zn(2+) ions and ionic species of As(III), Sb(III), Te(IV), and Se(IV). PMID:21315908

  4. Design of a simple cryogenic system for ultraviolet-visible absorption spectroscopy with a back-reflectance fiber optic probe.

    PubMed

    Vinyard, Andrew; Hansen, Kaj A; Byrd, Ross; Stuart, Douglas A; Hansen, John E

    2014-01-01

    We report a convenient and inexpensive technique for the rapid acquisition of absorption spectra from small samples at cryogenic temperatures using a home built cryostat with novel collection optics. A cylindrical copper block was constructed with a coaxial bore to hold a 4.00 mm diameter electron paramagnetic resonance (EPR) tube and mounted on a copper feed in thermal contact with liquid nitrogen. A 6.35 mm diameter hole was bored into the side of the cylinder so a fiber optic cable bundle could be positioned orthogonally to the EPR tube. The light passing through the sample is reflected off of the opposing surfaces of the EPR tube and surrounding copper, back through the sample. The emergent light is then collected using the fiber optic bundle and analyzed using a dispersive spectrometer. Absorption spectra for KMnO4 were measured between 400 and 700 nm. Absorption intensity at 506, 525, 545, and 567 nm was found to be proportional to concentration, displaying Beer's law-like behavior. The EPR tube had an internal diameter of 3.2 mm; the double pass of the probe beam through the sample affords a central path length of about 6.4 mm. Comparing these measurements with those recorded on a conventional tabletop spectrometer using a cuvette with a 10.00 mm path length, we consistently found a ratio between intensities of 0.58 rather than the anticipated 0.64. These 6% smaller values we attribute to the curvature of the EPR tube and transmission/reflection losses. This system is particularly well-suited to studying the kinetics and dynamics of chemical reactions at cryogenic temperatures. The rapid response (100 ms) and multiplex advantage provided the opportunity of recording simultaneous time courses at several wavelengths following initiation of a chemical reaction with a pulsed laser source. PMID:24405962

  5. Methods-comparison measurements during the Carbonaceous-Species Methods Comparison Study, Glendora, California, August 1986: tunable-diode laser absorption spectrometer measurements of HCHO, H/sub 2/O/sub 2/ and HNO/sub 3/. Final report

    SciTech Connect

    Mackay, G.I.; Schiff, H.I.

    1987-10-21

    As part of the Carbonaceous-Species Methods Comparison Study at Citrus College, Glendora CA, on August 11-21, 1986, Unisearch Associates participated in methods evaluation studies for formaldehyde (HCHO), hydrogen peroxide (H/sub 2/O/sub 2/) and nitric acid (HNO/sub 3/). These three species play important roles in photochemistry of urban and rural air, and their measurements provide sensitive tests for current acid deposition and urban smog models. Two tunable diode laser absorption spectrometers (TDLAS) were used in the methods evaluation study.

  6. Monolithic spectrometer

    DOEpatents

    Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

    1998-05-19

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

  7. Monolithic spectrometer

    DOEpatents

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  8. PC-based Data Acquisition System for X-ray Crystal Spectrometer

    NASA Astrophysics Data System (ADS)

    Nam, U. W.; Kong, K. N.; Park, Y. S.; Kim, Y. J.; Lee, S. G.; Bak, J. G.; Bitter, M.; Hill, K.; Moon, M. K.; Cheon, J. K.; Lee, C. H.

    2003-10-01

    A PC-based data acquisition system for an X-ray crystal spectrometer has been developed in order to measure the ion and electron temperature profile measurements on tokamak plasmas. The system can detect a 2D image of the plasma from a gas-filled delay line readout position-sensitive 2D detector and spherically-bent crystal in connection with N110 time to digital converter developed in European Synchrotron Radiation Facility. The N110 interface module with TMS320VC33 digital signal processor, and 16 Mbytes static memory and its supporting Windows OS image software are used for the PC-based data acquisition system. An USB (Universal Serial Bus) interface of the PC was used to get image data from the system with higher than 10 Mbytes/s throughput rate because of its simplicity and high-speed communication capability. The system has two acquisition modes - a static and dynamic modes - which can build 256 x 256, 512 x 512, 1024 x 1024 and 2048 x2048 image frames. The dynamic mode is designed to obtain and store the position and time information of each photon events simultaneously with the maximum count-rate capability up to 500 kHz. An overview and demonstration of the PC-based data acquisition system will be presented.

  9. Unmanned Aerial Mass Spectrometer Systems for In-Situ Volcanic Plume Analysis

    NASA Astrophysics Data System (ADS)

    Diaz, Jorge Andres; Pieri, David; Wright, Kenneth; Sorensen, Paul; Kline-Shoder, Robert; Arkin, C. Richard; Fladeland, Matthew; Bland, Geoff; Buongiorno, Maria Fabrizia; Ramirez, Carlos; Corrales, Ernesto; Alan, Alfredo; Alegria, Oscar; Diaz, David; Linick, Justin

    2015-02-01

    Technology advances in the field of small, unmanned aerial vehicles and their integration with a variety of sensor packages and instruments, such as miniature mass spectrometers, have enhanced the possibilities and applications of what are now called unmanned aerial systems (UAS). With such technology, in situ and proximal remote sensing measurements of volcanic plumes are now possible without risking the lives of scientists and personnel in charge of close monitoring of volcanic activity. These methods provide unprecedented, and otherwise unobtainable, data very close in space and time to eruptions, to better understand the role of gas volatiles in magma and subsequent eruption products. Small mass spectrometers, together with the world's smallest turbo molecular pump, have being integrated into NASA and University of Costa Rica UAS platforms to be field-tested for in situ volcanic plume analysis, and in support of the calibration and validation of satellite-based remote sensing data. These new UAS-MS systems are combined with existing UAS flight-tested payloads and assets, such as temperature, pressure, relative humidity, SO2, H2S, CO2, GPS sensors, on-board data storage, and telemetry. Such payloads are capable of generating real time 3D concentration maps of the Turrialba volcano active plume in Costa Rica, while remote sensing data are simultaneously collected from the ASTER and OMI space-borne instruments for comparison. The primary goal is to improve the understanding of the chemical and physical properties of emissions for mitigation of local volcanic hazards, for the validation of species detection and abundance of retrievals based on remote sensing, and to validate transport models.

  10. Design of Portable Mass Spectrometers with Handheld Probes: Aspects of the Sampling and Miniature Pumping Systems

    PubMed Central

    Chen, Chien-Hsun; Chen, Tsung-Chi; Zhou, Xiaoyu; Kline-Schoder, Robert; Sorensen, Paul; Cooks, R. Graham; Ouyang, Zheng

    2014-01-01

    Miniature mass spectrometry analytical systems of backpack configuration fitted with sampling probes could potentially be of significant interest for in-field, real-time chemical analysis. In this study, various configurations were explored in which a long narrow tube was used to connect the turbo and backing pumps used to create and maintain vacuum. Also, for the first time we introduced two new types of pumps for miniature mass spectrometers, the Creare 130g drag pump and Creare 350g scroll backing pump. These pumps, along with another Creare 550 turbo pump and the commercially available Pfeiffer HiPace 10 turbo and KnF diaphragm backing pumps, were tested with the backpack configurations. The system performance, especially the scan time, was characterized when used with a discontinuous atmospheric pressure interface (DAPI) for ion introduction. The pumping performance in the pressure region above 1 mtorr is critical for DAPI operation. The 550g turbo pump was shown to have a relatively higher pumping speed above 1 mtorr and gave a scan time of 300 ms, almost half the value obtained with the larger, heavier HiPace 10 often used with miniature mass spectrometers. The 350 g scroll pump was also found to be an improvement over the diaphragm pumps generally used as backing pumps. With a coaxial low temperature plasma ion source, direct analysis of low volatility compounds glass slides was demonstrated, including 1 ng DNP (2,4-Dinitrophenol) and 10ng TNT (2,4,6-trinitrotoluene) with Creare 550g turbo pump as well as 10 ng cocaine and 20 ng DNP with Creare 130g drag pump. PMID:25404157

  11. Design of Portable Mass Spectrometers with Handheld Probes: Aspects of the Sampling and Miniature Pumping Systems

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Hsun; Chen, Tsung-Chi; Zhou, Xiaoyu; Kline-Schoder, Robert; Sorensen, Paul; Cooks, R. Graham; Ouyang, Zheng

    2015-02-01

    Miniature mass spectrometry analytical systems of backpack configuration fitted with sampling probes could potentially be of significant interest for in-field, real-time chemical analysis. In this study, various configurations were explored in which a long narrow tube was used to connect the turbo and backing pumps used to create and maintain vacuum. Also, for the first time we introduced two new types of pumps for miniature mass spectrometers, the Creare 130 g drag pump and Creare 350 g scroll backing pump. These pumps, along with another Creare 550 turbo pump and the commercially available Pfeiffer HiPace 10 turbo and KnF diaphragm backing pumps, were tested with the backpack configurations. The system performance, especially the scan time, was characterized when used with a discontinuous atmospheric pressure interface (DAPI) for ion introduction. The pumping performance in the pressure region above 1 mtorr is critical for DAPI operation. The 550 g turbo pump was shown to have a relatively higher pumping speed above 1 mtorr and gave a scan time of 300 ms, almost half the value obtained with the larger, heavier HiPace 10 often used with miniature mass spectrometers. The 350 g scroll pump was also found to be an improvement over the diaphragm pumps generally used as backing pumps. With a coaxial low temperature plasma ion source, direct analysis of low volatility compounds glass slides was demonstrated, including 1 ng DNP (2,4-Dinitrophenol) and 10 ng TNT (2,4,6-trinitrotoluene) with Creare 550 g turbo pump as well as 10 ng cocaine and 20 ng DNP with Creare 130 g drag pump.

  12. Design of portable mass spectrometers with handheld probes: aspects of the sampling and miniature pumping systems.

    PubMed

    Chen, Chien-Hsun; Chen, Tsung-Chi; Zhou, Xiaoyu; Kline-Schoder, Robert; Sorensen, Paul; Cooks, R Graham; Ouyang, Zheng

    2015-02-01

    Miniature mass spectrometry analytical systems of backpack configuration fitted with sampling probes could potentially be of significant interest for in-field, real-time chemical analysis. In this study, various configurations were explored in which a long narrow tube was used to connect the turbo and backing pumps used to create and maintain vacuum. Also, for the first time we introduced two new types of pumps for miniature mass spectrometers, the Creare 130 g drag pump and Creare 350 g scroll backing pump. These pumps, along with another Creare 550 turbo pump and the commercially available Pfeiffer HiPace 10 turbo and KnF diaphragm backing pumps, were tested with the backpack configurations. The system performance, especially the scan time, was characterized when used with a discontinuous atmospheric pressure interface (DAPI) for ion introduction. The pumping performance in the pressure region above 1 mtorr is critical for DAPI operation. The 550 g turbo pump was shown to have a relatively higher pumping speed above 1 mtorr and gave a scan time of 300 ms, almost half the value obtained with the larger, heavier HiPace 10 often used with miniature mass spectrometers. The 350 g scroll pump was also found to be an improvement over the diaphragm pumps generally used as backing pumps. With a coaxial low temperature plasma ion source, direct analysis of low volatility compounds glass slides was demonstrated, including 1 ng DNP (2,4-Dinitrophenol) and 10 ng TNT (2,4,6-trinitrotoluene) with Creare 550 g turbo pump as well as 10 ng cocaine and 20 ng DNP with Creare 130 g drag pump. PMID:25404157

  13. Unmanned aerial mass spectrometer systems for in-situ volcanic plume analysis.

    PubMed

    Diaz, Jorge Andres; Pieri, David; Wright, Kenneth; Sorensen, Paul; Kline-Shoder, Robert; Arkin, C Richard; Fladeland, Matthew; Bland, Geoff; Buongiorno, Maria Fabrizia; Ramirez, Carlos; Corrales, Ernesto; Alan, Alfredo; Alegria, Oscar; Diaz, David; Linick, Justin

    2015-02-01

    Technology advances in the field of small, unmanned aerial vehicles and their integration with a variety of sensor packages and instruments, such as miniature mass spectrometers, have enhanced the possibilities and applications of what are now called unmanned aerial systems (UAS). With such technology, in situ and proximal remote sensing measurements of volcanic plumes are now possible without risking the lives of scientists and personnel in charge of close monitoring of volcanic activity. These methods provide unprecedented, and otherwise unobtainable, data very close in space and time to eruptions, to better understand the role of gas volatiles in magma and subsequent eruption products. Small mass spectrometers, together with the world's smallest turbo molecular pump, have being integrated into NASA and University of Costa Rica UAS platforms to be field-tested for in situ volcanic plume analysis, and in support of the calibration and validation of satellite-based remote sensing data. These new UAS-MS systems are combined with existing UAS flight-tested payloads and assets, such as temperature, pressure, relative humidity, SO2, H2S, CO2, GPS sensors, on-board data storage, and telemetry. Such payloads are capable of generating real time 3D concentration maps of the Turrialba volcano active plume in Costa Rica, while remote sensing data are simultaneously collected from the ASTER and OMI space-borne instruments for comparison. The primary goal is to improve the understanding of the chemical and physical properties of emissions for mitigation of local volcanic hazards, for the validation of species detection and abundance of retrievals based on remote sensing, and to validate transport models. PMID:25588720

  14. The Berkeley tunable far infrared laser spectrometers

    NASA Technical Reports Server (NTRS)

    Blake, G. A.; Laughlin, K. B.; Cohen, R. C.; Busarow, K. L.; Gwo, D.-H.

    1991-01-01

    A detailed description is presented for a tunable far infrared laser spectrometer based on frequency mixing of an optically pumped molecular gas laser with tunable microwave radiation in a Schottky point contact diode. The system has been operated on over 30 laser lines in the range 10-100/cm and exhibits a maximum absorption sensitivity near one part in a million. Each laser line can be tuned by + or - 110 GHz with first-order sidebands.

  15. Miniaturized system of a gas chromatograph coupled with a Paul ion trap mass spectrometer

    NASA Technical Reports Server (NTRS)

    Shortt, B. J.; Darrach, M. R.; Holland, Paul M.; Chutjian, A.

    2005-01-01

    Miniature gas chromatography (GC) and miniature mass spectrometry (MS) instrumentation has been developed to identify and quantify the chemical compounds present in complex mixtures of gases. The design approach utilizes micro-GC components coupled with a Paul quadrupole ion trap (QIT) mass spectrometer. Inherent to the system are high sensitivity, good dynamic range, good QIT resolution, low GC flow-rates to minimize vacuum requirements and the need for consumables; and the use of a modular approach to adapt to volatile organic compounds dissolved in water or present in sediment. Measurements are reported on system response to gaseous species at concentrations varying over four orders of magnitude. The ability of the system to deal with complicated mixtures is demonstrated, and future improvements are discussed. The GC/QIT system described herein has a mass, volume and power that are, conservatively, one-twentieth of those of commercial off-the-shelf systems. Potential applications are to spacecraft cabin-air monitoring, robotic planetary exploration and trace-species detection for residual gas analysis and environmental monitoring.

  16. An improved impaction-graphite furnace system for the direct and near real-time determination of cadmium, chromium, lead and manganese in aerosols and cigarette smoke by simultaneous multielement atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Lee, Yong-Ill; Smith, Mark V.; Indurthy, Suneetha; Deval, Anupama; Sneddon, Joseph

    1996-01-01

    The design, operating characteristics, and preliminary evaluation of an improved impaction-graphite furnace system, based on a theoretical study of particle size collected, are presented. After direct collection, the graphite furnace from the system is inserted in an atomic absorption spectrometer for analysis by simultaneous multielement atomic absorption spectrometry. This system has the potential for the direct and near real-time (few minutes) determination of metals in aerosols. The system has been preliminarily evaluated using aqueous solutions of chromium, and has then been applied to the determination of cadmium, chromium, lead, and manganese in cigarette smoke. Results show an increase ranging from almost five (lead) to sixteen (cadmium) over background levels.

  17. Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

    SciTech Connect

    2010-09-01

    BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

  18. Exploring the Saturn System in the Thermal Infrared: The Composite Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Flasar, F. M.; Kunde, V. g.; Abbas, M. M.; Achterberg, R. K.; Ade, P.; Barucci, A.; Bezard, B.; Bjoraker, G. L.; Brasunas, J. C.; Calcutt, S.

    2004-01-01

    The Composite Inbred Spectrometer (CIRS) is a remote-sensing Fourier Transform Spectrometer on the Cassini orbiter that measures thermal radiation over two decades in wave number, from 10 to 1400 cm (1 mm to 7pm), with a spectral resolution that can be set from 0.5 to 20 cm. The far in portion of the spectrum (10 - 600 cm) is measured with a polarizing interferometer having thermopile detectors with a common 4-mrad field of view. The middle infrared portion is measured with a traditional Michelson interferometer having two focal planes (600 - 1100cm, 1100-1400 cm). Each focal plane is composed of a 1x10 array of HgCdTe detectors, each detector having a 0.3-mrad field of view. CIRS observations will provide three-dimensional maps of temperature, gas composition, and aerosols/condensates of the atmospheres of Titan and Saturn with good vertical and horizontal resolution, from deep in their tropospheres to high in their mesospheres. CIRS ability to observe atmospheres in the limb viewing mode (in addition to nadir) offers the opportunity to provide accurate and highly resolved vertical profiles of these atmospheric variables. The ability to observe with high-spectral resolution should facilitate the identification of new constituents. CIRS will also map the thermal and compositional properties of the surfaces of Saturn's icy satellites. It will similarly map Saturn's rings, characterizing their formation and evolution. The combination of broad spectral range, programmable spectral resolution, the small detector fields of view, and an orbiting spacecraft platform will allow CIRS to observe the Saturnian system in the thermal infrared at a level of detail not previously achieved.

  19. Exploration of the Saturn System by the Cassini Mission: Observations with the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.

    2014-01-01

    The Cassini mission is a joint NASA-ESA international mission, launched on October 17, 1997 with 12 instruments on board, for exploration of the Saturn system. A composite Infrared Spectrometers is one of the major instruments. Successful insertion of the spacecraft in Saturn's orbit for an extended orbital tour occurred on July 1, 2004. The French Huygens-Probe on board, with six instruments was programmed for a soft landing on Titan's surface occurred in January 2005. The broad range scientific objectives of the mission are: Exploration of the Saturn system for investigations of the origin, formation, & evolution of the solar system, with an extensive range of measurements and the analysis of the data for scientific interpretations. The focus of research dealing with the Cassini mission at NASA/MSFC in collaboration with the NASA/Goddard Space Flight Center, JPL, as well as the research teams at Oxford/UK and Meudon Observatory/France, involves the Infrared observations of Saturn and its satellites, for measurements of the thermal structure and global distributions of the atmospheric constituents. A brief description of the Cassini spacecraft, the instruments, the objectives, in particular with the infrared observations of the Saturn system will be given. The analytical techniques for infrared radiative transfer and spectral inversion programs, with some selected results for gas constituent distributions will be presented.

  20. New data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer

    SciTech Connect

    Tamii, A.; Sakaguchi, H.; Takeda, H.; Yosoi, M.; Akimune, H.; Fujiwara, M.; Ogata, H.; Tanaka, M.; Togawa, H.

    1996-10-01

    This paper describes a new data acquisition system for the focal plane polarimeter of the Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP) in Osaka, Japan. Data are acquired by a Creative Electronic Systems (CES) Starburst, which is a CAMAC auxiliary crate controller equipped with a Digital Equipment Corporation (DEC) J11 microprocessor., The data on the Starburst are transferred to a VME single-board computer. A VME reflective memory module broadcasts the data to other systems through a fiber-optic link. A data transfer rate of 2.0 Mbytes/s between VME modules has been achieved by reflective memories. This rate includes the overhead of buffer management. The overall transfer rate, however, is limited by the performance of the Starburst to about 160 Kbytes/s at maximum. In order to further improve the system performance, the authors developed a new readout module called the Rapid Data Transfer Module (RDTM). RDTM`s transfer data from LeCroy PCOS III`s or 4298`s, and FERA/FERET`s directly to CES 8170 High Speed Memories (HSM) in VME crates. The data transfer rate of the RDTM from PCOS III`s to the HSM is about 4 Mbytes/s.

  1. Data acquisition system for an advanced x-ray imaging crystal spectrometer using a segmented position-sensitive detector.

    PubMed

    Nam, U W; Lee, S G; Bak, J G; Moon, M K; Cheon, J K; Lee, C H

    2007-10-01

    A versatile time-to-digital converter based data acquisition system for a segmented position-sensitive detector has been developed. This data acquisition system was successfully demonstrated to a two-segment position-sensitive detector. The data acquisition system will be developed further to support multisegmented position-sensitive detector to improve the photon count rate capability of the advanced x-ray imaging crystal spectrometer system. PMID:17979416

  2. A five-collector system for the simultaneous measurement of argon isotope ratios in a static mass spectrometer

    USGS Publications Warehouse

    Stacey, J.S.; Sherrill, N.D.; Dalrymple, G.B.; Lanphere, M.A.; Carpenter, N.V.

    1981-01-01

    A system is described that utilizes five separate Faraday-cup collector assemblies, aligned along the focal plane of a mass spectrometer, to collect simultaneous argon ion beams at masses 36-40. Each collector has its own electrometer amplifier and analog-to-digital measuring channel, the outputs of which are processed by a minicomputer that also controls the mass spectrometer. The mass spectrometer utilizes a 90?? sector magnetic analyzer with a radius of 23 cm, in which some degree of z-direction focussing is provided for all the ion beams by the fringe field of the magnet. Simultaneous measurement of the ion beams helps to eliminate mass-spectrometer memory as a significant source of measurement error during an analysis. Isotope ratios stabilize between 7 and 9 s after sample admission into the spectrometer, and thereafter changes in the measured ratios are linear, typically to within ??0.02%. Thus the multi-collector arrangement permits very short extrapolation times for computation of initial ratios, and also provides the advantages of simultaneous measurement of the ion currents in that errors due to variations in ion beam intensity are minimized. A complete analysis takes less than 10 min, so that sample throughput can be greatly enhanced. In this instrument, the factor limiting analytical precision now lies in short-term apparent variations in the interchannel calibration factors. ?? 1981.

  3. Analysis of aircraft spectrometer data with logarithmic residuals

    NASA Technical Reports Server (NTRS)

    Green, A. A.; Craig, M. D.

    1985-01-01

    Spectra from airborne systems must be analyzed in terms of their mineral-related absorption features. Methods for removing backgrounds and extracting these features one at a time from reflectance spectra are discussed. Methods for converting radiance spectra into a form similar to reflectance spectra so that the feature extraction procedures can be implemented on aircraft spectrometer data are also discussed.

  4. Multiple-Diode-Laser Gas-Detection Spectrometer

    NASA Technical Reports Server (NTRS)

    Webster, Christopher R.; Beer, Reinhard; Sander, Stanley P.

    1988-01-01

    Small concentrations of selected gases measured automatically. Proposed multiple-laser-diode spectrometer part of system for measuring automatically concentrations of selected gases at part-per-billion level. Array of laser/photodetector pairs measure infrared absorption spectrum of atmosphere along probing laser beams. Adaptable to terrestrial uses as monitoring pollution or control of industrial processes.

  5. A two-laser beam technique for improving the sensitivity of low frequency open path tunable diode laser absorption spectrometer (OP-TDLAS) measurements

    NASA Astrophysics Data System (ADS)

    Mohammad, Israa L.; Anderson, Gary T.; Chen, Youhua

    2013-09-01

    Open path tunable diode-laser absorption spectroscopy (OP-TDLAS) is a promising technique to detect low concentrations of possible biogenic gases on Mars. This technique finds the concentration of a gas by measuring the amount of laser light absorbed by gaseous molecules at a specific wavelength. One of the major factors limiting sensitivity in the TDLAS systems operating at low modulation frequencies is 1/f noise. 1/f noise is minimized in many spectroscopy systems by the use of high frequency modulation techniques. However, these techniques require complex instruments that include reference cells and other devices for calibration, making them relatively large and bulky. We are developing a spectroscopy system for space applications that requires small, low mass and low power instrumentation, making the high frequency techniques unsuitable. This paper explores a new technique using two-laser beam to reduce the affect of 1/f noise and increase the signal strength for measurements made at lower frequencies. The two lasers are excited at slightly different frequencies. An algorithm is used to estimate the noise in the second harmonic from the combined spectra of both lasers. This noise is subtracted from the signal to give a more accurate measurement of gas concentration. The error in estimation of 1/f noise is negligible as it corresponds to noise level made at much higher frequencies. Simulation results using ammonia gas and two lasers operating at 500 and 510 Hz respectively shows that this technique is able to decrease the error in estimation of gas concentration to 1/6 its normal value.

  6. A two-laser beam technique for improving the sensitivity of low frequency open path tunable diode laser absorption spectrometer (OP-TDLAS) measurements

    NASA Astrophysics Data System (ADS)

    Mohammad, Isra'a. Lateef

    Open path tunable diode-laser absorption spectroscopy (OP-TDLAS) is a promising technique that is proposed for detecting low concentrations of possible biogenic gases on Mars. This technique determines the concentration of a gas by measuring the amount of laser light absorbed by molecules at a specific wavelength that is characteristic of those molecules. One of the major factors limiting sensitivity in the OP-TDLAS systems is noise. At low modulation frequencies, 1/f noise usually dominates. This 1/f noise is minimized in many spectroscopy systems by use of high frequency techniques. However, these methods use complex instruments that include reference cells and other devices for calibration, making them relatively large and bulky. We have built a spectroscopy system for space applications that requires small, low mass and low power instrumentation, making the high frequency techniques unsuitable. This work explores a new technique that uses a two-laser beam to reduce the affect of 1/f noise and increase the signal strength for measurements made at lower frequencies. The two lasers are excited at slightly different frequencies. An algorithm is used to estimate the total noise in the second harmonic from the combined spectra of both lasers. This noise is subtracted from the signal to give a more accurate measurement of gas concentration. The error in estimation of 1/f noise is negligible as it corresponds to noise level made at much higher frequencies. Experimental results using ammonia gas and two lasers operating at 500 and 510 Hz respectively shows that this technique reduces the effect of 1/f noise by 1/3 its normal value. Furthermore, the error in estimation of gas concentration is also reduced.

  7. Development of the APEX experiment, preparatory activities for an airborne system supporting future space-borne imaging spectrometers in Europe

    NASA Astrophysics Data System (ADS)

    Schaepman, M.

    2002-06-01

    APEX is an airborne imaging spectrometer built in the framework of ESA PRODEX (Programme développement d'expériences scientifiques) with the support of ESA EO-EP. It is based on a Swiss/Belgian initiative and designed to be an airborne simulator for the support and development of future spaceborne systems for the study of land surface processes. It will be able to contribute to the simulation, calibration, and validation of planned ESA imaging spectrometer missions (e.g., MERIS/ENVISAT, SPECTRA, etc.) in the 400 - 2500 nm region of the spectrum. APEX will foster the use of imaging spectrometer data in Europe and will support the application development for imaging spectroscopy products. The industrial consortium building the instrument is composed out of joint Swiss/Belgian industries with the support of ESA EO-EP (e.g., detectors, calibration, technical management).

  8. The multianalyser system of the three axes neutron spectrometer PUMA: Pilot experiments with the innovative multiplex technique

    NASA Astrophysics Data System (ADS)

    Sobolev, Oleg; Hoffmann, Ron; Gibhardt, Holger; Jünke, Norbert; Knorr, Andreas; Meyer, Volker; Eckold, Götz

    2015-02-01

    A new type of multiplex technique for three axes neutron spectrometers has been realized and successfully commissioned at the PUMA spectrometer at FRM II. Consisting of eleven analyser-detector channels which can be configured individually, this technique is especially suitable for kinetic experiments where a single excitation spectrum is recorded as a function of time without the need to move the spectrometer. On a time-scale of seconds an entire spectrum can be recorded thus allowing users to monitor changes during fast kinetic processes in single shot experiments without the need for stroboscopic techniques. Moreover, the multianalyser system provides an efficient and rapid tool for mapping excitations in (Q,ω)-space. The results of pilot experiments demonstrate the performance of this new technique and a user-friendly software is presented which assists users during their experiments.

  9. [Stability analysis of on-board calibration system of spatially modulated imaging Fourier transform spectrometer].

    PubMed

    Gao, Jingz; Ji, Zhong-Ying; Wang, Zhong-Hou; Cui, Yan

    2010-04-01

    Spatially modulated imaging Fourier transform spectrometer (SMIFTS) was an instrument that depended on interference, and after calibration, the reconstruction spectrum can quantificationally reflect the diffuse reflection of target under sunshine. On-board calibration of SMIFTS confirmed the change of SMIFTS according to relative spectrum calibration, inspected long-time attenuation of SMIFTS optical system, and corrected export data of SMIFTS. According to the requirement of remote sensor application, it must stay in vacuum environment for a long time. As a radiant standard, the stability of lamp-house in long time is the most important characteristic of on-board calibration system. By calculation and experimentation, analyses of on-board calibration of SMIFTS, and testing spaceflight environment characteristic of on-board calibration, the difficulty in the key parts of on-board calibration of SMIFTS such as lamp-house, spectrum filter and integrating sphere was solved. According to the radiation-time stability testing for lamp-house and optics, particle-radiation testing, environmental-mechanics testing and hot vacuum examination, good result was obtained. By whole-aperture and part-field comparative wavelength calibration, the spectrum curve and before-launch interferogram were obtained. After comparison with reconstruction spectrum under different condition, the stability and credibility of SMIFTS on-board calibration system was proved. PMID:20545151

  10. An alpha–gamma coincidence spectrometer based on the Photon–Electron Rejecting Alpha Liquid Scintillation (PERALS®) system

    DOE PAGESBeta

    Cadieux, J. R.; Fugate, G. A.; King, III, G. S.

    2015-02-07

    Here, an alpha–gamma coincidence spectrometer has been developed for the measurement of selected actinide isotopes in the presence of high beta/gamma fields. The system is based on a PERALS® liquid scintillation counter for beta/alpha discrimination and was successfully tested with both high purity germanium and bismuth germanate, gamma-ray detectors using conventional analog electronics.

  11. Photoacoustic Experimental System to Confirm Infrared Absorption Due to Greenhouse Gases

    ERIC Educational Resources Information Center

    Kaneko, Fumitoshi; Monjushiro, Hideaki; Nishiyama, Masayoshi; Kasai, Toshio; Harris, Harold H.

    2010-01-01

    An experimental system for detecting infrared absorption using the photoacoustic (PA) effect is described. It is aimed for use at high-school level to illustrate the difference in infrared (IR) absorption among the gases contained in the atmosphere in connection with the greenhouse effect. The experimental system can be built with readily…

  12. Survey for z>3 damped Ly alpha absorption systems: the evolution of neutral gas

    NASA Technical Reports Server (NTRS)

    Storrie-Lombardi, L. J.; Wolfe, A. M.

    2000-01-01

    We have completed spectroscopic observations using LRIS on the Keck 1 telescope of 30 very high redshift quasars, 11 selected for the presence of damped Ly alpha absorption systems and 19 with redshifts z>3.5 not previously surveyed for absorption systems.

  13. The effect of age on systemic absorption and systemic disposition of bupivacaine after subarachnoid administration

    SciTech Connect

    Veering, B.T.; Burm, A.G.; Vletter, A.A.; van den Hoeven, R.A.; Spierdijk, J. )

    1991-02-01

    In order to evaluate the role of the pharmacokinetics of the age-related changes in the clinical profile of spinal anesthesia with bupivacaine, we studied the influence of age on the systemic absorption and systemic disposition of bupivacaine after subarachnoid administration in 20 male patients (22-81 yr), ASA Physical Status 1 or 2, by a stable isotope method. After subarachnoid administration of 3 ml 0.5% bupivacaine in 8% glucose, a deuterium-labeled analog (13.4 mg) was administered intravenously. Blood samples were collected for 24 h. Plasma concentrations of unlabeled and deuterium-labeled bupivacaine were determined with a combination of gas chromatography and mass fragmentography. Biexponential functions were fitted to the plasma concentration-time data of the deuterium-labeled bupivacaine. The systemic absorption was evaluated by means of deconvolution. Mono- and biexponential functions were fitted to the data of fraction absorbed versus time. The maximal height of analgesia and the duration of analgesia at T12 increased with age (r = 0.715, P less than 0.001; r = 0.640, P less than 0.01, respectively). In 18 patients the systemic absorption of bupivacaine was best described by a biexponential equation. The half-life of the slow systemic absorption process (r = -0.478; P less than 0.05) and the mean absorption time (r = -0.551; P less than 0.02) decreased with age. The total plasma clearance decreased with age (r = -0.650, P less than 0.002), whereas the mean residence time and terminal half-life increased with age (r = 0.597, P less than 0.01; r = 0.503, P less than 0.05).

  14. Drift-Chamber Gas System Controls Development for the CEBAF Large Acceptance Spectrometer

    SciTech Connect

    M. F. Vineyard; T. J. Carroll; M. N. Lack

    1996-07-01

    The CEBAF Large Acceptance Spectrometer (CLAS) is a superconducting toroidal magnet with a large volume of drift chambers for charged particle tracking. The performance of these chambers depends on accurate monitoring and control of the mixture, flow rate, pressure, temperature, and contaminant levels of the gas. To meet these requirements, a control system is being developed with EPICS. The interface hardware consists of VME ADCs and three RS-232 low-level hardware controllers. The RS-232 instruments include MKS 647A mass flow controllers to control and monitor the gas mixture and flow, MKS 146B pressure gauge controllers to measure pressures, and a Panametrics hygrometer to monitor temperatures and the concentrations of oxygen, water vapor, and ethane. Many of the parameters are available as analog signals which will be monitored with XYCOM VME analog input cards and configured for alarms and data logging. The RS-232 interfaces will be used for remote control of the hardware and verification of the analog readings. Information will be passed quickly and efficiently to and from the user through a graphical user interface. A discussion of the requirements and design of the system is presented.

  15. The tropospheric emission spectrometer (TES) for the Earth Observing System (EOS)

    NASA Astrophysics Data System (ADS)

    Beer, R.

    In recent years, increasing concern has been expressed about Global Change - the natural and anthropogenic alteration of the Earth's environment involving global greenhouse warming and the associated climate change, urban and regional atmospheric pollution, acid deposition, regional increases in tropospheric zone, and the decrease in stratospheric ozone. A common theme among these problems is that they all involve those tropospheric trace gases which are fundamental to the biosphere-troposphere interaction, the chemistry of the free troposphere itself, and troposphere-stratosphere exchange. The chemical species involved all have spectral signatures within the near and mid infrared that can now be measured by advanced techniques of remote-sensing infrared spectroradiometry. Such a system is the Tropospheric Emission Spectrometer (TES), now in Phase B definition for the Earth Observing System (EOS) polar platforms. TES addresses these objectives by obtaining radiometrically calibrated, linewidth-limited spectral resolution, infrared spectra of the lower atmosphere using both natural thermal emission and reflected sunlight (where appropriate) in three different, but fully programmable, modes: a gobal mode, a pointed mode, and a limb-viewing mode. The goals of TES, its instrumentation, operational modes, sensitivity and data handling are discussed.

  16. The tropospheric emission spectrometer (TES) for the Earth Observing System (EOS)

    NASA Technical Reports Server (NTRS)

    Beer, R.

    1992-01-01

    In recent years, increasing concern has been expressed about Global Change - the natural and anthropogenic alteration of the Earth's environment involving global greenhouse warming and the associated climate change, urban and regional atmospheric pollution, acid deposition, regional increases in tropospheric zone, and the decrease in stratospheric ozone. A common theme among these problems is that they all involve those tropospheric trace gases which are fundamental to the biosphere-troposphere interaction, the chemistry of the free troposphere itself, and troposphere-stratosphere exchange. The chemical species involved all have spectral signatures within the near and mid infrared that can now be measured by advanced techniques of remote-sensing infrared spectroradiometry. Such a system is the Tropospheric Emission Spectrometer (TES), now in Phase B definition for the Earth Observing System (EOS) polar platforms. TES addresses these objectives by obtaining radiometrically calibrated, linewidth-limited spectral resolution, infrared spectra of the lower atmosphere using both natural thermal emission and reflected sunlight (where appropriate) in three different, but fully programmable, modes: a gobal mode, a pointed mode, and a limb-viewing mode. The goals of TES, its instrumentation, operational modes, sensitivity and data handling are discussed.

  17. Properties of low-redshift QSO absorption systems - QSO-galaxy pairs

    NASA Technical Reports Server (NTRS)

    Womble, Donna S.

    1993-01-01

    The chance proximity of QSOs and galaxies provides unique opportunities to probe the extent and content of gas in the foreground galaxies through evaluation of the incidence and strength of absorption lines in the spectra of the background QSOs. Recent results on the observed properties of these low-redshift, heavy-element absorption systems are summarized. These results are discussed in the context of the galaxy morphologies and environments and are briefly compared with Galactic absorption and with the inferred properties of higher-redshift QSO absorption systems.

  18. Properties of multilayer optical systems formed by layers with small absorption in inclined falling of radiation

    NASA Astrophysics Data System (ADS)

    Karyaev, Konstantin V.; Zhoga, Eugene V.; Putilin, Eduard S.

    2000-10-01

    Multilayer dielectric systems find wide employment in different fields of science and engineering. Dielectric systems, formed by layers with small absorption, attract particular interest. Value of absorption, as a rule, depends on structure of the system (order and optical thickness of layers), angle of incidence and wavelength of radiation. Experiment shows that there are peaks of absorption on certain angles of incidence and wavelength, but behavior of absorption wasn't studied well. Model of a system, formed by isotropic layers settled on semiinfinite substate proved to be a good approximation for many of real optical systems. We studied pecularities in spectral dependencies of reflection, transmission and absorption coefficients in dependance on the angle of incidence and wavelength of falling radiation with flat wave front. Problem was solved on the basis of Maxwell equations and corresponding boundary conditions.

  19. Connecting the Silicate Dust and Gas Properties of Distant Galaxies Using Quasar Absorption Systems

    NASA Astrophysics Data System (ADS)

    Aller, Monique C.; Kulkarni, Varsha P.; York, Donald G.; Welty, Daniel E.; Vladilo, Giovanni; Som, Debopam; Lackey, Kyle; Dwek, Eli; Beiranvand, Nassim; Morrison, Sean

    2016-01-01

    We present recent results from our program investigating the silicate dust properties in distant galaxies using quasar absorption systems. The dust and gas properties of distant galaxies can be characterized by studying the absorption features produced by them along the sightlines to luminous background quasars. Based on our prior finding that silicate dust absorption in z<1.5 quasar absorption systems exhibits a range of optical depths and absorption feature substructures, suggestive of silicate grain property variations, we are investigating silicate dust absorption in quasar absorption systems toward quasars with archival Spitzer Space Telescope Infrared Spectrograph (IRS) spectra. We present our measurements of the 10 and/or 18 micron silicate dust absorption feature(s) in these systems, and discuss constraints on the grain properties, such as composition and crystallinity, based on the shape and substructure present in these features. We also investigate the correlations between the silicate dust properties and the reddening. Connections between the silicate dust and gas phase metal absorption properties can also be probed for some of our targets with archival ground-based spectra. These relationships will yield valuable insights into the star formation history and evolution of metals and dust. This work is supported by NASA through ADAP grant NNX14AG74G and by an award issued by JPL/Caltech, and from US-NSF grant AST-1108830 to the University of South Carolina.

  20. Exploration of the Saturn System by the Cassini Mission: Observations with the Cassini Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.

    2014-01-01

    Outline: Introduction to the Cassini mission, and Cassini mission Objectives; Cassini spacecraft, instruments, launch, and orbit insertion; Saturn, Rings, and Satellite, Titan; Composite Infrared Spectrometer (CIRS); and Infrared observations of Saturn and titan.

  1. Proportional-Integral-Derivative (PID) Temperature Control and Data Acquisition System for Faraday Filter based Sodium Spectrometer

    NASA Astrophysics Data System (ADS)

    Semerjyan, Vardan; Yuan, Tao

    2011-04-01

    Sodium (Na) Faraday filters based spectrometer is a relatively new instrument to study sodium nightglow as well as sodium and oxygen chemistry in the mesopause region. Successful spectrometer measurement demands highly accurate control of filter temperature. The ideal, long-term operation site for the Na spectrometer is an isolated location with minimum nocturnal sky background. Thus, the remote control of the filter temperature is a requirement for such operation, whereas current temperature controllers can only be operated manually. The proposed approach is aimed to not only enhance the temperature control, but also achieve spectrometer's remote and autonomous operation. In the meantime, the redesign should relief the burden of the cost for multi temperature controllers. The program will give to the operator flexibility in setting the operation temperatures of the Faraday filters, monitoring the temperature variations, and logging the data during the operation. Research will make diligent efforts to attach preliminary data analysis subroutine to the main control program. The real-time observation results will be posted online after the observation is completed. This approach also can be a good substitute for the temperature control system currently used to run the Lidar system at Utah State University (USU).

  2. THE STANDARD CALIBRATION INSTRUMENT AUTOMATION SYSTEM FOR THE ATOMIC ABSORPTION SPECTROPHOTOMETER. PART III: PROGRAM DOCUMENTATION

    EPA Science Inventory

    This report contains complete documentation for the 15 programs and 11 data files of the EPA Atomic Absorption Instrument Automation System. The system incorporates the following major features: (1) multipoint calibration using first, second, or third degree regression or linear ...

  3. A All-Vacuum High Resolution Fourier Transform Spectrometer with Absorption Pathlengths up to 352 M: Acetylene Spectrum at 1.4-1.7 Microns.

    NASA Astrophysics Data System (ADS)

    Keppler, Karen Ann

    1995-01-01

    The spectra of acetylene (C_2H _2) and of water vapor have been recorded at room temperature with Doppler- or pressure -broadening-limited resolution at pathlengths up to 352m. The spectra were obtained with the combination of a FTIR (Fourier Transform Infrared) spectrometer, evacuated transfer optics, and a multipass cell of 4m base length. The measurements were performed at the Justus-Liebig-Universitat in Giessen, Germany, using the FTIR spectrometer at that university, the multipass cell assembled at The Ohio State University, and the vacuum transfer optics designed by the author. The regions in which the spectra were recorded are 5900-7150 cm^{-1} and 1850-6600 cm^{-1}. Calibration difficulties pertaining to the determination of the absolute accuracy of the data have been resolved, and molecular parameters have been extracted for the HCCH data. These calibration problems were not documented in earlier studies using high resolution Fourier transform spectrometers. For this reason, the dissertation addresses this matter in somewhat greater detail. This work contains a description of the technology used to obtain the data, and a description of the calibration of the spectra to make them suitable for future use as secondary wavenumber calibration standards. The bands detected for the first time in this study have been reported, and updated energy level diagrams for HCCH and H^{13}CCH have been included. The molecular parameters obtained from the HCCH spectra have been presented. The appendices include, among others, the basic observational data, a spectral map and associated wavenumber lists of HCCH, and a description of the weighting scheme developed by the author for Fourier Transform spectra.

  4. Exoplanetary Systems with SAFARI: A Far Infrared Imaging Spectrometer for SPICA

    NASA Astrophysics Data System (ADS)

    Goicoechea, J. R.; Swinyard, B.

    2010-10-01

    The far-infrared (far-IR) spectral window plays host to a wide range of spectroscopic diagnostics with which to study planetary disk systems and exoplanets at wavelengths completely blocked by the Earth atmosphere. These include the thermal emission of dusty belts in debris disks, the water ice features in the “snow lines” of protoplanetary disks, as well as many key chemical species (O, OH, H2O, NH3, HD, etc.). These tracers play a critical diagnostic role in a number of key areas including the early stages of planet formation and potentially, exoplanets. The proposed Japanese-led IR space telescope SPICA, with its 3m-class cooled mirror (˜5 K) will be the next step in sensitivity after ESA’s Herschel Space Observatory (successfully launched in May 2009). SPICA is a candidate “M-mission” in ESA’s Cosmic Vision 2015-2025 process. We summarize the science possibilities of SAFARI: a far-IR imaging-spectrometer (covering the &sim34 - 210 μm band) that is one of a suite of instruments for SPICA.

  5. Studying two-level systems in Josephson junctions with a Josephson junction defect spectrometer

    NASA Astrophysics Data System (ADS)

    Stoutimore, M. J. A.; Khalil, M. S.; Gladchenko, Sergiy; Simmonds, R. W.; Lobb, C. J.; Osborn, K. D.

    2012-02-01

    We have fabricated and measured Josephson junction defect spectrometers (JJDSs), which are frequency-tunable, nearly-harmonic oscillators that probe two-level systems (TLSs) in the barrier of a Josephson junction (JJ). A JJDS consists of the JJ under study fabricated with a parallel capacitor and inductor such that it can accommodate a wide range of junction inductances, LJ0, while maintaining an operating frequency, f01, in the range of 4-8 GHz. In this device, the parallel inductance helps the JJ maintain linearity over a wide range of frequencies. This architecture allows for the testing of JJs with a wide range of areas and barrier materials, and in the first devices we have tested Al/AlOx/Al JJs. By applying a magnetic flux bias to tune f01, we detect TLSs in the JJ barrier as splittings in the device spectrum. We will present our results toward identifying and quantifying these TLSs, which are known to cause decoherence in quantum devices that rely on JJs.

  6. Dual-aureole and sun spectrometer system for airborne measurements of aerosol optical properties.

    PubMed

    Zieger, Paul; Ruhtz, Thomas; Preusker, Rene; Fischer, Jürgen

    2007-12-10

    We have designed an airborne spectrometer system for the simultaneous measurement of the direct sun irradiance and the aureole radiance in two different solid angles. The high-resolution spectral radiation measurements are used to derive vertical profiles of aerosol optical properties. Combined measurements in two solid angles provide better information about the aerosol type without additional and elaborate measuring geometries. It is even possible to discriminate between absorbing and nonabsorbing aerosol types. Furthermore, they allow to apply additional calibration methods and simplify the detection of contaminated data (e.g., by thin cirrus clouds). For the characterization of the detected aerosol type a new index is introduced that is the slope of the aerosol phase function in the forward scattering region. The instrumentation is a flexible modular setup, which has already been successfully applied in airborne and ground-based field campaigns. We describe the setup as well as the calibration of the instrument. In addition, example vertical profiles of aerosol optical properties--including the aureole measurements--are shown and discussed. PMID:18071387

  7. HIRIS - NASAS's High-Resolution Imaging Spectrometer for the Earth Observing System

    NASA Technical Reports Server (NTRS)

    Dozier, J.

    1992-01-01

    Modern Earth science is beginning to examine interactions among the different terrestrial components at all temporal and spatial scales. Such a global perspective requires an integrated remote-sensing program, the Earth Observing System (EOS), which uses instruments throughout the electromagnetic spectrum to collect data about the Earth's surface, oceans and atmosphere over a range of selected scales. At the finest scales, we will require instruments capable of detailed sampling both spatially and spectrally. We have designed the High-Resoulution Imaging Spectrometer (HIRIS) to acquire simultaneous images in 192 spectral bands in the dominant wavelengths of the solar spectrum, 0.4 to 2.5 micrometers, at a spectral sampling interval of 10 nm. The ground instantaneous field of view (GIFOV) will be 30 m over a 24 km swath. A pointing capability will allow image acquisition up to +52 deg/-30 deg down track and +/-45 deg or more cross-track. Thus we will be able to study surface spectral bidirectional reflectance properties and variations in atmospheric attenuation with viewing angle. The cross-track pointing will also allow multiple viewing opportunities during one 16-day orbital revisit cycle, so that any part of the Earth may be imaged in a two-day period.

  8. Cryogenic optical systems for the rapid infrared imager/spectrometer (RIMAS)

    NASA Astrophysics Data System (ADS)

    Capone, John I.; Content, David A.; Kutyrev, Alexander S.; Robinson, Frederick D.; Lotkin, Gennadiy N.; Toy, Vicki L.; Veilleux, Sylvain; Moseley, Samuel H.; Gehrels, Neil A.; Vogel, Stuart N.

    2014-07-01

    The Rapid Infrared Imager/Spectrometer (RIMAS) is designed to perform follow-up observations of transient astronomical sources at near infrared (NIR) wavelengths (0.9 - 2.4 microns). In particular, RIMAS will be used to perform photometric and spectroscopic observations of gamma-ray burst (GRB) afterglows to compliment the Swift satellite's science goals. Upon completion, RIMAS will be installed on Lowell Observatory's 4.3 meter Discovery Channel Telescope (DCT) located in Happy Jack, Arizona. The instrument's optical design includes a collimator lens assembly, a dichroic to divide the wavelength coverage into two optical arms (0.9 - 1.4 microns and 1.4 - 2.4 microns respectively), and a camera lens assembly for each optical arm. Because the wavelength coverage extends out to 2.4 microns, all optical elements are cooled to ~70 K. Filters and transmission gratings are located on wheels prior to each camera allowing the instrument to be quickly configured for photometry or spectroscopy. An athermal optomechanical design is being implemented to prevent lenses from loosing their room temperature alignment as the system is cooled. The thermal expansion of materials used in this design have been measured in the lab. Additionally, RIMAS has a guide camera consisting of four lenses to aid observers in passing light from target sources through spectroscopic slits. Efforts to align these optics are ongoing.

  9. Interstellar Silicate Dust Grain Properties in Distant Galaxies Probed by Quasar Absorption Systems

    NASA Astrophysics Data System (ADS)

    Aller, Monique C.; Kulkarni, Varsha P.; York, Donald G.; Welty, Daniel E.; Vladilo, Giovanni; Som, Debopam

    2015-01-01

    Dust grains are a fundamental component of the interstellar medium, and significantly impact many of the physical processes driving galaxy evolution, including star formation, and the heating, cooling and ionization of interstellar material. Using the absorption features produced by dust in the spectra of luminous background quasars, it is possible to study the properties of extragalactic interstellar dust grains. We will present results from an ongoing program utilizing existing Spitzer Space Telescope infrared quasar spectra to probe silicate dust grain properties in z<1.4 quasar absorption systems. In combination with complementary ground-based data on associated gas-phase metal absorption lines, we explore connections between the interstellar dust and gas in the quasar absorption systems. Our project yields clear detections of the 10 micron silicate dust absorption feature in the studied systems, as well as detections of the 18 micron silicate dust absorption feature in sources with adequate spectral coverage. Based on measured variations in the breath, peak wavelength, and substructure of the 10 micron absorption features, there appear to be differences in the silicate dust grain properties from system-to-system. We also show indications of trends between the gas-phase metal properties, such as metallicity and gas velocity spread, with the silicate dust grain absorption properties. Support for this work is provided by NASA through an award issued by JPL/Caltech and through NASA grant NNX14AG74G, and from National Science Foundation grants AST-0908890 and AST-1108830 to the University of South Carolina.

  10. Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

    SciTech Connect

    Schwarz, G.F.; Rybach, L.; Klingele, E.E.

    1997-09-01

    Airborne radiometric surveys are finding increasingly wider application in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack-mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma-ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power-plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose-rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Goesgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

  11. Vertical profiles of atmospheric fluorescent aerosols observed by a mutil-channel lidar spectrometer system

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Huang, J.; Zhou, T.; Sugimoto, N.; Bi, J.

    2015-12-01

    Zhongwei Huang1*, Jianping Huang1, Tian Zhou1, Nobuo Sugimoto2, Jianrong Bi1 and Jinsen Shi11Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. 2Atmospheric Environment Division, National Institutes for Environmental Studies, Tsukuba, Japan Email: huangzhongwei@lzu.edu.cn Abstract Atmospheric aerosols have a significant impact on regional and globe climate. The challenge in quantifying aerosol direct radiative forcing and aerosol-cloud interactions arises from large spatial and temporal heterogeneity of aerosol concentrations, compositions, sizes, shape and optical properties (IPCC, 2007). Lidar offers some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. To investigate the characterization of atmospheric aerosols (especially bioaerosols) with high spatial and temporal resolution, we developed a Raman/fluorescence/polarization lidar system employed a multi-channel spectrometer, with capabilities of providing measurements of Raman scattering and laser-induced fluorescence excitation at 355 nm from atmospheric aerosols. Meanwhile, the lidar system operated polarization measurements both at 355nm and 532nm wavelengths, aiming to obtain more information of aerosols. It employs a high power pulsed laser and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum about 178 nm with spectral resolution 5.7 nm, mainly including an F/3.7 Crossed Czerny-Turner spectrograph, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at four sites across northwest China, during 2014 spring field observation that conducted by Lanzhou University. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and

  12. Multidimensional spectrometer

    SciTech Connect

    Zanni, Martin Thomas; Damrauer, Niels H.

    2010-07-20

    A multidimensional spectrometer for the infrared, visible, and ultraviolet regions of the electromagnetic spectrum, and a method for making multidimensional spectroscopic measurements in the infrared, visible, and ultraviolet regions of the electromagnetic spectrum. The multidimensional spectrometer facilitates measurements of inter- and intra-molecular interactions.

  13. The -145 km/S Absorption System of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Vieira, G.; Gull, T. R.; Danks, A.; Johansson, S.

    2002-01-01

    With the STIS E230H mode (R-118,000) , we have identified about twenty absorption components in line of sight from Eta Carinae. Two components, one at -513 km/s and another at -145 W s , are quite different in character from the others, mostly at intermediate velocities. The -145 km/s component is significantly wider in fwhm, is seen in many more species, and the lower level can be above 20,000/cm, well above the 2000/cm noted in the -513 km/s component. In the spectral region from 2400 to 3160A, approximately 500 absorption lines have been identified. In this poster, we will present line identifications and atomic parameters of the measured lines, hopefully providing insight as to what levels are being excited and by what processes.

  14. The Use of a Microprocessor-Controlled, Video Output Atomic Absorption Spectrometer as an Educational Tool in a Two-Year Technical Curriculum.

    ERIC Educational Resources Information Center

    Kerfoot, Henry B.

    Based on instructional experiences at Charles County Community College, Maryland, this report examines the pedagogical advantage of teaching atomic absorption (AA) spectroscopy with an AA spectrophotometer that is equipped with a microprocessor and video output mechanism. The report first discusses the growing importance of AA spectroscopy in…

  15. High-throughput operando Raman-quadrupole mass spectrometer (QMS) system to screen catalytic systems.

    PubMed

    García-Casado, Manuel; Prieto, José; Vico-Ruiz, Emilio; Lozano-Diz, Enrique; Goberna-Selma, Consuelo; Bañares, Miguel A

    2014-01-01

    This paper describes the design and setup of a high-throughput Raman system for an array of eight parallel catalytic reactors during reaction conditions. The "operando" methodology combines in situ spectroscopy during catalytic reaction with a simultaneous activity measurement. The high-throughput operando Raman system, multi-operando, is a device that automates this operando methodology for several catalyst samples at the same time, all samples being in the same reaction conditions. We describe how the system is made, how Raman system positions and acquires spectra, and how each reactor outlet gas is selected and analyzed. PMID:24405956

  16. Jejunal and ileal absorption of oxprenolol in man: influence of nutrients and digestive secretions on jejunal absorption and systemic availability.

    PubMed Central

    Godbillon, J; Vidon, N; Palma, R; Pfeiffer, A; Franchisseur, C; Bovet, M; Gosset, G; Bernier, J J; Hirtz, J

    1987-01-01

    1 Study I evaluated the absorption of oxprenolol in the ileum, compared to jejunum, in healthy volunteers by an intestinal perfusion technique. Around 80 mg of drug were delivered as a saline solution directly in the small bowel. 2 Samples taken 30 cm distally to the site of perfusion showed that 63% of perfused oxprenolol was absorbed in the jejunum and 48% in the ileum; the differences were significant. 3 The plasma concentration-time profiles were similar for the two perfusions. The AUC and Cmax values of free and conjugated oxprenolol for the jejunal perfusion were significantly lower than those of ileum. They showed large but consistent intersubject variations in the two treatments. 4 Study II investigated, using the same technique, the influence of nutrients and digestive secretions on jejunal absorption and systemic availability of this drug. A saline (in treatments A and B) or a nutrient (in treatment C) solution containing oxprenolol was perfused into the jejunum below a balloon either inflated (A) or deflated (B and C). 5 The disappearance rate of oxprenolol from the jejunum was unaffected by endogenous secretions. The mean amount of drug absorbed along a 30-cm jejunal segment accounted for 52 (A) and 57% (B) of the total amount perfused. The intestinal absorption rate was markedly increased in the presence of nutrients (mean amount absorbed 96% for C). 6 The change in the rate of disappearance from the intestine had no effect on the systemic availability of oxprenolol (mean AUC values 8740, 8250 and 8020 nmol l-1 h for A, B and C, respectively) or its elimination from plasma.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3663450

  17. Space-resolved vacuum ultraviolet spectrometer system for edge impurity and temperature profile measurement in HL-2A

    SciTech Connect

    Cui Zhengying; Fu Bingzhong; Huang Yuan; Sun Ping; Gao Yadong; Xu Yuan; Lu Ping; Wang Quanming; Ding Xuantong; Yang Qingwei; Duan Xuru; Morita, Shigeru; Dong Chunfeng

    2010-04-15

    A 1 m normal incidence vacuum ultraviolet (VUV) spectrometer has been developed for spatial distribution measurement of edge impurity line emission in the wavelength range of 300-3200 A on HL-2A tokamak. A vertical profile of the impurity line emission is measured with a space-resolved slit placed between an entrance slit and a grating of the spectrometer. Two concave 1200 grooves/mm gratings blazed at 800 and 1500 A are set on a rotatable holder in the spectrometer, which gives wavelength dispersion of 0.12 mm/A. A back-illuminated charge-coupled device is used as a detector with an image size of 6.7x26.6 mm{sup 2} (26x26 {mu}m{sup 2}/pixel). An excellent spatial resolution of 2 mm is obtained with good spectral resolution of 0.15 A when the space-resolved slit of 50 {mu}m in width is used. The space-resolved spectra thus provide three radial profiles of emission line intensity, ion temperature, and poloidal rotation. The electron temperature can be measured by the intensity ratio, e.g., CIII 2s{sup 2}-2s3p (386 A)/2s{sup 2}-2s2p (977 A). The sensitivity of the spectrometer is calibrated in situ by using the VUV bremsstrahlung continuum radiation emitted from the tokamak plasma. A good performance of the spectrometer system for the edge impurity and temperature profile measurements is presented with results on Ohmic and H-mode discharges.

  18. New detections of Galactic molecular absorption systems toward ALMA calibrator sources

    NASA Astrophysics Data System (ADS)

    Ando, Ryo; Kohno, Kotaro; Tamura, Yoichi; Izumi, Takuma; Umehata, Hideki; Nagai, Hiroshi

    2016-02-01

    We report on Atacama Large Millimeter/submillimeter Array (ALMA) detections of molecular absorption lines in Bands 3, 6, and 7 toward four radio-loud quasars, which were observed as the bandpass and complex gain calibrators. The absorption systems, three of which are newly detected, are found to be Galactic origin. Moreover, HCO absorption lines toward two objects are detected, which almost doubles the number of HCO absorption samples in the Galactic diffuse medium. In addition, high HCO-to-H13CO+ column density ratios are found, suggesting that the interstellar media (ISM) observed toward the two calibrators are in photodissociation regions, which observationally illustrates the chemistry of diffuse ISM driven by ultraviolet (UV) radiation. These results demonstrate that calibrators in the ALMA Archive are potential sources for the quest for new absorption systems and for detailed investigation of the nature of the ISM.

  19. XMM-Newton/Reflection Grating Spectrometer detection of the missing interstellar O VII Kα absorption line in the spectrum of Cyg X-2

    NASA Astrophysics Data System (ADS)

    Cabot, Samuel H. C.; Wang, Q. Daniel; Yao, Yangsen

    2013-05-01

    The hot interstellar medium is an important part of the Galactic ecosystem and can be effectively characterized through X-ray absorption line spectroscopy. However, in a study of the hot medium using the accreting neutron star X-ray binary, Cyg X-2, as a background light source, a mystery came about when the putatively strong O VII Kα line was not detected in Chandra grating observations, while other normally weaker lines such as O VII Kβ as well as O VI and O VIII Kα are clearly present. We have investigated the grating spectra of Cyg X-2 from 10 XMM-Newton observations, in search of the missing line. We detect it consistently in nine of these observations, but the line is absent in the remaining one observation or is inconsistent with the detection in others at a ˜4σ confidence level. This absence of the line resembles that seen in the Chandra observations. Similarly, the O VI Kα line is found to disappear occasionally, but not in concert with the variation of the O VII Kα line. All these variations are most likely due to the presence of changing O VII and O VI Kα emission lines of Cyg X-2, which are blurred together with the absorption ones in the X-ray spectra. A re-examination of the Chandra grating data indeed shows evidence for a narrow emission line slightly off the O VI Kα absorption line. We further show that narrow N V emission lines with varying centroids and fluxes are present in far-ultraviolet spectra from the Cosmic Origins Spectrograph aboard the Hubble Space Telescope. These results provide new constraints on the accretion around the neutron star and on the X-ray-heating of the stellar companion. The understanding of these physical processes is also important to the fidelity of using such local X-ray binaries for interstellar absorption line spectroscopy.

  20. Mass-specific optical absorption coefficients and imaginary part of the complex refractive indices of mineral dust components measured by a multi-wavelength photoacoustic spectrometer

    NASA Astrophysics Data System (ADS)

    Utry, N.; Ajtai, T.; Pintér, M.; Tombácz, E.; Illés, E.; Bozóki, Z.; Szabó, G.

    2015-01-01

    Mass-specific optical absorption coefficients (MACs) and the imaginary part (κ) of the refractive indices of various mineral dust components including silicate clays (illite, kaolin and bentonite), oxides (quartz, hematite and rutile), and carbonate (limestone) were determined at the wavelengths of 1064, 532, 355 and 266 nm. The MAC values were calculated from aerosol optical absorption coefficients measured by a multi-wavelength photoacoustic (PA) instrument, the mass concentration and the number size distribution of the generated aerosol samples as well as the size transfer functions of the measuring instruments. Values of κ were calculated from the measured and particle-loss-corrected data by using a Mie-theory-based retrieval algorithm. The determined values could be used for comparisons with calculated wavelength-dependent κ values typically deduced from bulk-phase measurements by using indirect measurement methods. Accordingly, the presented comparison of the measured and calculated aerosol optical absorption spectra revealed the strong need for standardized sample preparation and measurement methodology in case of bulk-phase measurements.

  1. Clear evidence for the presence of O VI absorption in QSO metal systems

    NASA Technical Reports Server (NTRS)

    Lu, Limin; Savage, Blair D.

    1993-01-01

    We have detected O VI 1031.93 A, 1037.62 A doublet absorption in a composite QSO spectrum formed from a large number of intervening C IV absorption systems. The detections constitute the first firm evidence for the presence of O VI in intervening QSO metal absorption systems. The equivalent width of the detected O VI absorption implies an O VI column density N(O VI) not less than 2.8 x 10 exp 14/sq cm. This value, together with the nondetection of the N V 1238.82 A, 1242.80 A doublet absorption, suggests that N(O VI)/N(N V) not less than 4.4. For collisionally ionized gas with a solar O to N abundance ratio in thermal equilibrium the above ratio requires a temperature T not less than 2.5 x 10 exp 5 K. It is found that C IV systems which show low-ionization species and those which do not both have associated O VI absorption, suggesting that O VI is probably present in all C IV systems. We also find that C IV systems which show low-ionization species on average have stronger high-ionization absorption lines than those which do not. A simple interpretation was given to explain this trend.

  2. Comparison of Ozone Retrievals from the Pandora Spectrometer System and Dobson Spectrophotometer in Boulder, Colorado

    NASA Technical Reports Server (NTRS)

    Herman, J.; Evans, R.; Cede, A.; Abuhassan, N.; Petropavlovskikh, I.; McConville, G.

    2015-01-01

    A comparison of retrieved total column ozone (TCO) amounts between the Pandora #34 spectrometer system and the Dobson #061 spectrophotometer from direct-sun observations was performed on the roof of the Boulder, Colorado, NOAA building. This paper, part of an ongoing study, covers a 1-year period starting on 17 December 2013. Both the standard Dobson and Pandora TCO retrievals required a correction, TCO(sub corr) = TCO (1 + C(T)), using a monthly varying effective ozone temperature, T(sub E), derived from a temperature and ozone profile climatology. The correction is used to remove a seasonal difference caused by using a fixed temperature in each retrieval algorithm. The respective corrections C(T(sub E)) are C(sub Pandora) = 0.00333(T(sub E) - 225) and C(sub Dobson) = -0.0013(T(sub E) - 226.7) per degree K. After the applied corrections removed most of the seasonal retrieval dependence on ozone temperature, TCO agreement between the instruments was within 1% for clear-sky conditions. For clear-sky observations, both co-located instruments tracked the day-to-day variation in total column ozone amounts with a correlation of r(exp 2) = 0.97 and an average offset of 1.1 +/- 5.8 DU. In addition, the Pandora TCO data showed 0.3% annual average agreement with satellite overpass data from AURA/OMI (Ozone Monitoring Instrument) and 1% annual average offset with Suomi-NPP/OMPS (Suomi National Polar-orbiting Partnership, the nadir viewing portion of the Ozone Mapper Profiler Suite).

  3. Expert systems technology applied to instrument operation and data acquisition of a triple quadrupole mass spectrometer (TQMS)

    SciTech Connect

    Wong, C.M.

    1984-01-01

    This presentation covers the work done at Lawrence Livermore National Laboratory by some computer programmers and analytical chemists specializing in mass spectrometry to develop an expert system for real-time tuning and optimization of operations of a triple quadrupole mass spectrometer (TQMS). This capability is important to increase the sensitivity possible for selected compounds throughout the entire mass range of the instrument, rather than settling for the traditional normalized calibration which lowers sensitivity at both ends of the mass scale.

  4. The -145 km/s Absorption System of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Vieira, G. L.; Gull, T. R.; Danks, A. C.; Johansson, S.

    2002-12-01

    With the STIS E230H mode (R 118,000), we have identified about twenty absorption components in line of sight from Eta Carinae. Two components, one at -513 km/s and another at -145 km/s, are quite different in character from the others, mostly at intermediate velocities (See adjacent posters by T. Gull and A. Danks). The -145 km/s component is significantly wider in fwhm, is seen in many more species, and the lower level can be above 20,000 cm-1, well above the 2000 cm-1 noted in the -513 km/s component. In the spectral region from 2400 to 3160A, approximately 500 absorption lines have been identified. In this poster, we will present line identifications and atomic parameters of the measured lines, hopefully providing insight as to what levels are being excited and by what processes. Observations were accomplished through STScI under proposal 9242 (Danks, P.I.). Funding is through the STIS GTO resources.

  5. Z(eff) profile measurement system with an optimized Czerny-Turner visible spectrometer in large helical device.

    PubMed

    Zhou, H Y; Morita, S; Goto, M; Chowdhuri, M B

    2008-10-01

    Z(eff) measurement system using a visible spectrometer has been newly designed and constructed instead of an old interference filter system to eliminate line emissions from the signal and to measure the Z(eff) value in low-density plasmas. The system consists of the Czerny-Turner-type spectrometer with a charge-coupled device camera and 44 optical fibers vertical array. The spectrometer is equipped with an additional toroidal mirror for further reduction in the astigmatism in addition to a flat and two spherical mirrors and three gratings (110, 120, and 1200 grooves/mm) with 30 cm focal length. The images from 44 optical fibers can be detected without astigmatism in a wavelength range of 200-900 nm. Combination of the optical fiber (core diameter: 100 microm) with the lens (focal length: 30 mm) provides spatial resolution of 30 mm at the plasma center. Results clearly indicate a very good focus image of the fiber and suggest the absence of the cross-talk between adjacent fiber images. Absolute intensity calibration has been done using a standard tungsten lamp to analyze the Z(eff) value. The bremsstrahlung profile and resultant Z(eff) profile have been obtained after Abel inversion of the signals observed in large helical device plasmas with elliptical poloidal cross section. PMID:19044678

  6. Z{sub eff} profile measurement system with an optimized Czerny-Turner visible spectrometer in large helical device

    SciTech Connect

    Zhou, H. Y.; Chowdhuri, M. B.; Morita, S.; Goto, M.

    2008-10-15

    Z{sub eff} measurement system using a visible spectrometer has been newly designed and constructed instead of an old interference filter system to eliminate line emissions from the signal and to measure the Z{sub eff} value in low-density plasmas. The system consists of the Czerny-Turner-type spectrometer with a charge-coupled device camera and 44 optical fibers vertical array. The spectrometer is equipped with an additional toroidal mirror for further reduction in the astigmatism in addition to a flat and two spherical mirrors and three gratings (110, 120, and 1200 grooves/mm) with 30 cm focal length. The images from 44 optical fibers can be detected without astigmatism in a wavelength range of 200-900 nm. Combination of the optical fiber (core diameter: 100 {mu}m) with the lens (focal length: 30 mm) provides spatial resolution of 30 mm at the plasma center. Results clearly indicate a very good focus image of the fiber and suggest the absence of the cross-talk between adjacent fiber images. Absolute intensity calibration has been done using a standard tungsten lamp to analyze the Z{sub eff} value. The bremsstrahlung profile and resultant Z{sub eff} profile have been obtained after Abel inversion of the signals observed in large helical device plasmas with elliptical poloidal cross section.

  7. Miniature Low Power Submillimeter-Wave Spectrometer for Detection of Water in the Solar System

    NASA Technical Reports Server (NTRS)

    Boric-Lubecke, Olga; Denning, Richard F.; Janssen, Michael A.; Frerking, Margaret A.

    1997-01-01

    The mass and power of a heterodyne spectrometer must be greatly reduced to satisfy small space mission constraints. We report on a 220 GHz receiver, requiring less than 4.8 W, with a mass of 1.25 kg. The mass and power savings are achieved through reducing components to a minimum, while providing performance for a Martian atmospheric sounder.

  8. SCINTILLATION SPECTROMETER

    DOEpatents

    Bell, P.R.; Francis, J.E.

    1960-06-21

    A portable scintillation spectrometer is described which is especially useful in radio-biological studies for determining the uptake and distribution of gamma -emitting substances in tissue. The spectrometer includes a collimator having a plurality of apertures that are hexagonal in cross section. Two crystals are provided: one is activated to respond to incident rays from the collimator; the other is not activated and shields the first from external radiation.

  9. Ionization states of metallic absorption-line systems in continua of quasars

    NASA Technical Reports Server (NTRS)

    Denda, Kiyomi; Ikeuchi, Satoru

    1993-01-01

    Ionization states of metallic absorption-line systems in continua of quasars (QSO's) are studied, assuming that the metallic lines arise in gaseous halos of high-redshift galaxies in photoionization equilibrium under the background UV radiation, and constraints on the intensity and spectral shape of the UV radiation are obtained. Then a structure of absorbers suitable for all of the metallic absorption line systems are discussed.

  10. A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Sargent, M. R.; Sayres, D. S.; Smith, J. B.; Witinski, M.; Allen, N. T.; Demusz, J. N.; Rivero, M.; Tuozzolo, C.; Anderson, J. G.

    2013-07-01

    We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT/LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT/LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-α hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-α, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons, in

  11. A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere.

    PubMed

    Sargent, M R; Sayres, D S; Smith, J B; Witinski, M; Allen, N T; Demusz, J N; Rivero, M; Tuozzolo, C; Anderson, J G

    2013-07-01

    We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT∕LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT∕LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-α hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-α, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons

  12. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    SciTech Connect

    Cui, Z. Q.; Chen, Z. J.; Xie, X. F.; Peng, X. Y.; Hu, Z. M.; Du, T. F.; Ge, L. J.; Zhang, X.; Yuan, X.; Fan, T. S.; Chen, J. X.; Li, X. Q. E-mail: guohuizhang@pku.edu.cn; Zhang, G. H. E-mail: guohuizhang@pku.edu.cn; Xia, Z. W.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.

    2014-11-15

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  13. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak.

    PubMed

    Cui, Z Q; Chen, Z J; Xie, X F; Peng, X Y; Hu, Z M; Du, T F; Ge, L J; Zhang, X; Yuan, X; Xia, Z W; Hu, L Q; Zhong, G Q; Lin, S Y; Wan, B N; Fan, T S; Chen, J X; Li, X Q; Zhang, G H

    2014-11-01

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G. PMID:25430242

  14. Design of a magnetic shielding system for the time of flight enhanced diagnostics neutron spectrometer at Experimental Advanced Superconducting Tokamak

    NASA Astrophysics Data System (ADS)

    Cui, Z. Q.; Chen, Z. J.; Xie, X. F.; Peng, X. Y.; Hu, Z. M.; Du, T. F.; Ge, L. J.; Zhang, X.; Yuan, X.; Xia, Z. W.; Hu, L. Q.; Zhong, G. Q.; Lin, S. Y.; Wan, B. N.; Fan, T. S.; Chen, J. X.; Li, X. Q.; Zhang, G. H.

    2014-11-01

    The novel neutron spectrometer TOFED (Time of Flight Enhanced Diagnostics), comprising 90 individual photomultiplier tubes coupled with 85 plastic scintillation detectors through light guides, has been constructed and installed at Experimental Advanced Superconducting Tokamak. A dedicated magnetic shielding system has been constructed for TOFED, and is designed to guarantee the normal operation of photomultiplier tubes in the stray magnetic field leaking from the tokamak device. Experimental measurements and numerical simulations carried out employing the finite element method are combined to optimize the design of the magnetic shielding system. The system allows detectors to work properly in an external magnetic field of 200 G.

  15. A study of the feasibility of mechanical pumps for use with the Pioneer-Venus probe mass spectrometer inlet system

    NASA Technical Reports Server (NTRS)

    Thomas, N. C.; Crosmer, W. E.; Nowak, D.

    1973-01-01

    A survey of mechanical vacuum pumps was completed. A small Roots blower for flight mass spectrometer applications was evaluated with respect to system operating parameters in a number of different modes of operation. The survey indicated that a metal bellows pump might be a viable alternative for the systems requirements. The results of the study are given, including current status of possible flight-type pumps, a systems analysis using available pumps, and recommendations for fabrication and tests of a potential flight-type pump.

  16. Sensitivity calibration of an imaging extreme ultraviolet spectrometer-detector system for determining the efficiency of broadband extreme ultraviolet sources

    SciTech Connect

    Fuchs, S.; Roedel, C.; Bierbach, J.; Paz, A. E.; Foerster, E.; Paulus, G. G.; Krebs, M.; Haedrich, S.; Limpert, J.; Kuschel, S.; Wuensche, M.; Hilbert, V.; Zastrau, U.

    2013-02-15

    We report on the absolute sensitivity calibration of an extreme ultraviolet (XUV) spectrometer system that is frequently employed to study emission from short-pulse laser experiments. The XUV spectrometer, consisting of a toroidal mirror and a transmission grating, was characterized at a synchrotron source in respect of the ratio of the detected to the incident photon flux at photon energies ranging from 15.5 eV to 99 eV. The absolute calibration allows the determination of the XUV photon number emitted by laser-based XUV sources, e.g., high-harmonic generation from plasma surfaces or in gaseous media. We have demonstrated high-harmonic generation in gases and plasma surfaces providing 2.3 {mu}W and {mu}J per harmonic using the respective generation mechanisms.

  17. A differential optical absorption spectroscopy method for retrieval from ground-based Fourier transform spectrometers measurements of the direct solar beam

    NASA Astrophysics Data System (ADS)

    Huo, Yanfeng; Duan, Minzheng; Tian, Wenshou; Min, Qilong

    2015-08-01

    A differential optical absorption spectroscopy (DOAS)-like algorithm is developed to retrieve the column-averaged dryair mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs—one weak and one strong absorption channel—are used to retrieve from measurements of the shortwave infrared (SWIR) band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are less sensitive to temperature and H2O uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network (TCCON) measurements under clear-sky conditions at two sites (Tsukuba and Bremen) are used to derive xxxx for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.

  18. SPECIES: a versatile spectrometer based on optical-feedback cavity-enhanced absorption for in situ balloon-borne and airborne measurements

    NASA Astrophysics Data System (ADS)

    Jacquet, Patrick; Catoire, Valery; Robert, Claude; Chartier, Michel; Huret, Nathalie; Desbois, Thibault; Marocco, Nicola; Kassi, Samir; Kerstel, Eric; Romanini, Daniele

    2015-04-01

    Over the last twenty years, thanks to significant technological advances in measurement techniques, our understanding of the chemistry and dynamics of the upper troposphere and stratosphere has progressed significantly. However some key questions remain unsolved, and new ones arise in the changing climate context. The full recovery of the ozone layer and the delay of recovery, the impact of the climate change on the stratosphere and the role of this one as a feedback are almost unknown. To address these challenges, one needs instruments able to measure a wide variety of trace gas species simultaneously with a wide vertical range. In this context, LPC2E and LIPHY are developing a new balloon-borne and airborne instrument: SPECIES (SPECtromètre Infrarouge à lasErs in Situ, i.e. in-Situ Infrared lasEr SPECtrometer). Based on the Optical Feedback Cavity Enhanced Spectroscopy technique, combined with mid-infrared quantum cascade lasers, this instrument will offer unprecedented performances in terms of the vertical extent of the measurements, from ground to the middle stratosphere, and the number of molecular species simultaneously measured with sub-ppb detection limits (among others: NO, N2O, HNO3, H2O2, HCl, HOCl, CH3Cl, COF2, HCHO, HCOOH, O3, NH3 NO2, H2O, OCS, SO2). Due to high frequency measurement (>0.5 Hz) it shall offer very high spatial resolution (a few meters).

  19. In vitro and in vivo percutaneous absorption of retinol from cosmetic formulations: Significance of the skin reservoir and prediction of systemic absorption

    SciTech Connect

    Yourick, Jeffrey J. Jung, Connie T.; Bronaugh, Robert L.

    2008-08-15

    The percutaneous absorption of retinol (Vitamin A) from cosmetic formulations was studied to predict systemic absorption and to understand the significance of the skin reservoir in in vitro absorption studies. Viable skin from fuzzy rat or human subjects was assembled in flow-through diffusion cells for in vitro absorption studies. In vivo absorption studies using fuzzy rats were performed in glass metabolism cages for collection of urine, feces, and body content. Retinol (0.3%) formulations (hydroalcoholic gel and oil-in-water emulsion) containing {sup 3}H-retinol were applied and absorption was measured at 24 or 72 h. All percentages reported are % of applied dose. In vitro studies using human skin and the gel and emulsion vehicles found 0.3 and 1.3% retinol, respectively, in receptor fluid at 24 h. Levels of absorption in the receptor fluid increased over 72 h with the gel and emulsion vehicles. Using the gel vehicle, in vitro rat skin studies found 23% in skin and 6% in receptor fluid at 24 h, while 72-h studies found 18% in skin and 13% in receptor fluid. Thus, significant amounts of retinol remained in rat skin at 24 h and decreased over 72 h, with proportional increases in receptor fluid. In vivo rat studies with the gel found 4% systemic absorption of retinol after 24 h and systemic absorption did not increase at 72 h. Retinol remaining in rat skin after in vivo application was 18% and 13% of the applied dermal dose after 24 and 72 h, respectively. Similar observations were made with the oil-in water emulsion vehicle in the rat. Retinol formed a reservoir in rat skin both in vivo and in vitro. Little additional retinol was bioavailable after 24 h. Comparison of these in vitro and in vivo results for absorption through rat skin indicates that the 24-h in vitro receptor fluid value accurately estimated 24-h in vivo systemic absorption. Therefore, the best single estimate of retinol systemic absorption from in vitro human skin studies is the 24-h receptor

  20. Absolute sensitivity calibration of vacuum and extreme ultraviolet spectrometer systems and Z(eff) measurement based on bremsstrahlung continuum in HL-2A tokamak.

    PubMed

    Zhou, Hangyu; Cui, Zhengying; Morita, Shigeru; Fu, Bingzhong; Goto, Motoshi; Sun, Ping; Dong, Chunfeng; Gao, Yadong; Xu, Yuan; Lu, Ping; Yang, Qingwei; Duan, Xuru

    2012-10-01

    A grazing-incidence flat-field extreme ultraviolet (EUV) spectrometer has been newly developed in HL-2A tokamak. Typical spectral lines are observed from intrinsic impurities of carbon, oxygen, iron, and extrinsic impurity of helium in the wavelength range of 20 Å-500 Å. Bremsstrahlung continuum is measured at different electron densities of HL-2A discharges to calibrate absolute sensitivity of the EUV spectrometer system and to measure effective ionic charge, Z(eff). The sensitivity of a vacuum ultraviolet (VUV) spectrometer system is also absolutely calibrated in overlapped wavelength range of 300 Å-500 Å by comparing the intensity between VUV and EUV line emissions. PMID:23126850

  1. Absolute sensitivity calibration of vacuum and extreme ultraviolet spectrometer systems and Z{sub eff} measurement based on bremsstrahlung continuum in HL-2A tokamak

    SciTech Connect

    Zhou Hangyu; Cui Zhengying; Fu Bingzhong; Sun Ping; Gao Yadong; Xu Yuan; Lu Ping; Yang Qingwei; Duan Xuru; Morita, Shigeru; Goto, Motoshi; Dong Chunfeng

    2012-10-15

    A grazing-incidence flat-field extreme ultraviolet (EUV) spectrometer has been newly developed in HL-2A tokamak. Typical spectral lines are observed from intrinsic impurities of carbon, oxygen, iron, and extrinsic impurity of helium in the wavelength range of 20 A-500 A. Bremsstrahlung continuum is measured at different electron densities of HL-2A discharges to calibrate absolute sensitivity of the EUV spectrometer system and to measure effective ionic charge, Z{sub eff}. The sensitivity of a vacuum ultraviolet (VUV) spectrometer system is also absolutely calibrated in overlapped wavelength range of 300 A-500 A by comparing the intensity between VUV and EUV line emissions.

  2. Design, construction, establishment of proof of principle, and testing of a spectrometer to permit spectroelectrochemical investigations of actinides in a confined system

    SciTech Connect

    Dasgupta, P.K.; Li, J.

    1999-02-01

    This study examines the design, construction, and performance of a spectrometer that was designed and built for UV-visible absorption spectroscopic studies in molten salt media. Contrary to previous designs in the literature, the authors found that furnace and chemical components can be located away from the instrument and electronics. In studying the performance of the spectrometer, they used a potassium chloride eutectic mixture as the molten salt medium. They found that UV-visible absorption spectroscopic studies can be conveniently created in a molten alkali halide media with inexpensive equipment coupled with good sensitivity and precision. Further research will focus on designing a suitable fiber optic probe that will allow the authors to monitor the molten salt process on-line.

  3. High frequency ultrasonic-assisted CO2 absorption in a high pressure water batch system.

    PubMed

    Tay, W H; Lau, K K; Shariff, A M

    2016-11-01

    Physical absorption process is always nullified by the presence of cavitation under low frequency ultrasonic irradiation. In the present study, high frequency ultrasonic of 1.7MHz was used for the physical absorption of CO2 in a water batch system under elevated pressure. The parameters including ultrasonic power and initial feed pressure for the system have been varied from 0 to 18W and 6 to 41bar, respectively. The mass transfer coefficient has been determined via the dynamic pressure-step method. Besides, the actual ultrasonic power that transmitted to the liquid was measured based on calorimetric method prior to the absorption study. Subsequently, desorption study was conducted as a comparison with the absorption process. The mechanism for the ultrasonic assisted absorption has also been discussed. Based on the results, the mass transfer coefficient has increased with the increasing of ultrasonic power. It means that, the presence of streaming effect and the formation of liquid fountain is more favorable under high frequency ultrasonic irradiation for the absorption process. Therefore, high frequency ultrasonic irradiation is suggested to be one of the potential alternatives for the gas separation process with its promising absorption enhancement and compact design. PMID:27245970

  4. FINGERPRINTING INORGANIC ARSENIC AND ORGANOARSENIC COMPOUNDS IN IN SITU OIL SHALE RETORT AND PROCESS VOTERS USING A LIQUID CHROMATOGRAPH COUPLED WITH AN ATOMIC ABSORPTION SPECTROMETER AS A DETECTOR

    SciTech Connect

    Fish, Richard H.; Brinckman, Frederick E.; Jewett, Kenneth L.

    1981-07-01

    Inorganic arsenic and organoarsenic compounds were speciated in seven oil shale retort and process waters, including samples from simulated, true and modified in situ processes, using a high performance liquid chromatograph automatically coupled to a graphite furnace atomic absorption detector. The molecular forms of arsenic at ppm levels (({micro}g/mL) in these waters are identified for the first time, and shown to include arsenate, methylarsonic acid and phenylarsonic acid. An arsenic-specific fingerprint chromatogram of each retort or process water studied has significant impliestions regarding those arsenical species found and those marginally detected, such as dimethylarsinic acid and the suspected carcinogen arsenite. The method demonstrated suggests future means for quantifying environmental impacts of bioactive organometal species involved in oil shale retorting technology.

  5. Lidar reflectance from snow at 2.05  μm wavelength as measured by the JPL Airborne Laser Absorption Spectrometer.

    PubMed

    Spiers, Gary D; Menzies, Robert T; Jacob, Joseph C

    2016-03-10

    We report airborne measurements of lidar directional reflectance (backscatter) from land surfaces at a wavelength in the 2.05 μm CO₂ absorption band, with emphasis on snow-covered surfaces in various natural environments. Lidar backscatter measurements using this instrument provide insight into the capabilities of lidar for both airborne and future global-scale CO₂ measurements from low Earth orbit pertinent to the NASA Active Sensing of CO₂ Emissions over Nights, Days, and Seasons mission. Lidar measurement capability is particularly useful when the use of solar scattering spectroscopy is not feasible for high-accuracy atmospheric CO₂ measurements. Consequently, performance in high-latitude and winter season environments is an emphasis. Snow-covered surfaces are known to be dark in the CO₂ band spectral regions. The quantitative backscatter data from these field measurements help to elucidate the range of backscatter values that can be expected in natural environments. PMID:26974792

  6. Approaches for achieving long-term accuracy and precision of δ18O and δ2H for waters analyzed using laser absorption spectrometers.

    PubMed

    Wassenaar, Leonard I; Coplen, Tyler B; Aggarwal, Pradeep K

    2014-01-21

    The measurement of δ(2)H and δ(18)O in water samples by laser absorption spectroscopy (LAS) are adopted increasingly in hydrologic and environmental studies. Although LAS instrumentation is easy to use, its incorporation into laboratory operations is not as easy, owing to extensive offline data manipulation required for outlier detection, derivation and application of algorithms to correct for between-sample memory, correcting for linear and nonlinear instrumental drift, VSMOW-SLAP scale normalization, and in maintaining long-term QA/QC audits. Here we propose a series of standardized water-isotope LAS performance tests and routine sample analysis templates, recommended procedural guidelines, and new data processing software (LIMS for Lasers) that altogether enables new and current LAS users to achieve and sustain long-term δ(2)H and δ(18)O accuracy and precision for these important isotopic assays. PMID:24328223

  7. Early Results on the Saturn System from the Composite Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Flasar, F. M.

    2005-01-01

    The Composite Infrared Spectrometer (CIRS) is a remote-sensing Fourier Transform Spectrometer on the Cassini orbiter that measures thermal radiation over two decades in wavenumber, from 10 to 1400 /cm (1 mm to 7 microns), with a spectral resolution that can be set from 0.5 to 15.5 /cm. The far infrared portion of the spectrum (10-600 /cm) is measured with a polarizing interferometer having thermopile detectors with a common 4-mrad field of view. The middle infrared portion is measured with a traditional Michelson interferometer having two focal planes (600-1100 /cm, 1100-1400 cm). Each focal plane is composed of a 1x10 array of HgCdTe detectors, each detector having a 0.3-mrad field of view. More complete descriptions of the instrument and investigation are given in and. A brief description of the first results from observations through the Saturn orbital insertion period can be found in.

  8. A new mass spectrometer system for investigating laser-induced vaporization phenomena

    NASA Technical Reports Server (NTRS)

    Lincoln, K. A.

    1974-01-01

    A laser has been combined with a mass spectrometer in a new configuration developed for studies of high-temperature materials. A vacuum-lock, solid-sample inlet is mounted at one end of a cylindrical, high-vacuum chamber one meter in length with a nude ion-source, time-of-flight mass spectrometer at the opposite end. The samples are positioned along the axis of the chamber at distances up to one meter from the ion source, and their surfaces are vaporized by a pulsed laser beam entering via windows on one side of the chamber. The instrumentation along with its capabilities is described, and results from laser-induced vaporization of several graphites are presented.

  9. Cooling system for the soft x-ray spectrometer (SXS) onboard ASTRO-H

    NASA Astrophysics Data System (ADS)

    Fujimoto, Ryuichi; Mitsuda, Kazuhisa; Yamasaki, Noriko; Takei, Yoh; Tsujimoto, Masahiro; Sugita, Hiroyuki; Sato, Yoichi; Shinozaki, Keisuke; Okamoto, Atsushi; Ohashi, Takaya; Ishisaki, Yoshitaka; Ezoe, Yuichiro; Ishikawa, Kumi; Murakami, Masahide; Kitamoto, Shunji; Murakami, Hiroshi; Tamagawa, Toru; Kawaharada, Madoka; Yamaguchi, Hiroya; Sato, Kosuke; Hoshino, Akio; Kanao, Kenichi; Yoshida, Seiji; Miyaoka, Mikio; Dipirro, Michael; Shirron, Peter; Sneiderman, Gary; Kelley, Richard L.; Porter, F. Scott; Kilbourne, Caroline A.; Crow, John; Mattern, Andrea; Kashani, Ali; McCammon, Dan

    2010-07-01

    The Soft X-ray Spectrometer (SXS) is a cryogenic high resolution X-ray spectrometer onboard the X-ray astronomy satellite ASTRO-H. The detector array is cooled down to 50 mK using a 3-stage adiabatic demagnetization refrigerator (ADR). The cooling chain from room temperature to the ADR heat-sink is composed of superfluid liquid He, a 4He Joule-Thomson cryocooler, and 2-stage Stirling cryocoolers. It is designed to keep 30 L of liquid He for more than 3 years in the nominal case. It is also designed with redundant subsystems throughout from room temperature to the ADR heat-sink, to alleviate failure of a single cryocooler or loss of liquid He.

  10. Imaging spectrometers for remote sensing from space

    NASA Technical Reports Server (NTRS)

    Chrisp, M. P.; Breckinridge, J. B.; Macenka, S. A.; Page, N. A.

    1986-01-01

    Three imaging spectrometers and two camera systems for remote sensing are described. Two of the imaging spectrometers are versions of the Visible and Infrared Mapping Spectrometer (VIMS) for Mars Observer and the Comet Rendezvous Asteroid Flyby (CRAF) mission. The other spectrometer is the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) which is currently under construction. The optical imaging systems are the wide angle and narrow angle cameras for the CRAF mission.

  11. Ultraviolet absorption of common spacecraft contaminants. [to control effects of contaminants on optical systems

    NASA Technical Reports Server (NTRS)

    Colony, J. A.

    1979-01-01

    Organic contamination of ultraviolet optical systems is discussed. Degradation of signal by reflection, scattering, interference, and absorption is shown. The first three processes depend on the physical state of the contaminant while absorption depends on its chemical structure. The latter phenomenon is isolated from the others by dissolving contaminants in cyclohexane and determining absorption spectra from 2100A to 3600A. A variety of materials representing the types of contaminants responsible for most spaceflight hardware problems is scanned and the spectra is presented. The effect of thickness is demonstrated for the most common contaminant, di(2 ethyl hexyl)phthalate, by scanning successive dilutions.

  12. Balloon-borne scanning spectrometer system for atmospheric extinction studies in the 350-1100 nm spectral region

    NASA Technical Reports Server (NTRS)

    Thompson, D. A.; Pepin, T. J.; Lane, R. W.

    1982-01-01

    A scanning spectrometer system which is capable of being flown in high-altitude balloon studies of the earth's atmosphere is presented. The instrument is small, has a large operative wavelength range of 350-1100 nm, high data density, and real-time data telemetry to ground. A computer software package is used to provide a real-time monitor of balloon gondola and instrument performance, with the software reliability enhanced by proof of correctness techniques and exhibiting the high degree of reliability necessary for the monitoring system.

  13. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    PubMed

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV. PMID:26773821

  14. Concurrent multiaxis differential optical absorption spectroscopy system for the measurement of tropospheric nitrogen dioxide.

    PubMed

    Leigh, Roland J; Corlett, Gary K; Friess, Udo; Monks, Paul S

    2006-10-01

    The development of a new concurrent multiaxis (CMAX) sky viewing spectrometer to monitor rapidly changing urban concentrations of nitrogen dioxide is detailed. The CMAX differential optical absorption spectroscopy (DOAS) technique involves simultaneous spectral imaging of the zenith and off-axis measurements of spatially resolved scattered sunlight. Trace-gas amounts are retrieved from the measured spectra using the established DOAS technique. The potential of the CMAX DOAS technique to derive information on rapidly changing concentrations and the spatial distribution of NO2 in an urban environment is demonstrated. Three example data sets are presented from measurements during 2004 of tropospheric NO2 over Leicester, UK (52.62 degrees N, 1.12 degrees W). The data demonstrate the current capabilities and future potential of the CMAX DOAS method in terms of the ability to measure real-time spatially disaggregated urban NO2. PMID:16983440

  15. Airborne measurements of formaldehyde employing a high-performance tunable diode laser absorption system

    NASA Astrophysics Data System (ADS)

    Fried, Alan; Wert, Bryan P.; Walega, James G.; Richter, Dirk A.; Potter, William T.

    2002-09-01

    Formaldehyde (CH2O) is a ubiquitous component of both the remote atmosphere as well as the polluted urban atmosphere. This important gas-phase intermediate is a primary emission product from hydrocarbon combustion sources as well as from oxidation of natural hydrocarbons emitted by plants and trees. Through its subsequent decomposition, formaldehyde is a source of reactive hydrogen radicals, which control the oxidation capacity of the atmosphere. Because ambient CH2O concentrations attain levels as high as several tens of parts-per-billion (ppbv) in urban areas to levels as low as tens of parts-per-trillion (pptv) in the remote background atmosphere, ambient measurements become quite challenging, particularly on airborne platforms. The present paper discusses an airborne tunable diode laser absorption spectrometer, which has been developed and refined over the past 6 years, for such demanding measurements. The results from a recent study will be presented.

  16. Microbolometer imaging spectrometer.

    PubMed

    Johnson, William R; Hook, Simon J; Shoen, Steven M

    2012-03-01

    Newly developed, high-performance, long-wave- and mid-wave-IR Dyson spectrometers offer a compact, low-distortion, broadband, imaging spectrometer design. The design is further accentuated when coupled to microbolometer array technology. This novel coupling allows radiometric and spectral measurements of high-temperature targets. It also serves to be unique since it allows for the system to be aligned warm. This eliminates the need for cryogenic temperature cycling. Proof of concept results are shown for a spectrometer with a 7.5 to 12.0 μm spectral range and approximately 20 nm per spectral band (~200 bands). Results presented in this Letter show performance for remote hot targets (>200 °C) using an engineering grade spectrometer and IR commercial lens assembly. PMID:22378399

  17. A Fully Redundant On-Line Mass Spectrometer System Used to Monitor Cryogenic Fuel Leaks on the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Griffin, Timothy P.; Naylor, Guy R.; Haskell, William D.; Breznik, Greg S.; Mizell, Carolyn A.; Helms, William R.; Voska, N. (Technical Monitor)

    2002-01-01

    An on-line gas monitoring system was developed to replace the older systems used to monitor for cryogenic leaks on the Space Shuttles before launch. The system uses a mass spectrometer to monitor multiple locations in the process, which allows the system to monitor all gas constituents of interest in a nearly simultaneous manner. The system is fully redundant and meets all requirements for ground support equipment (GSE). This includes ruggedness to withstand launch on the Mobile Launcher Platform (MLP), ease of operation, and minimal operator intervention. The system can be fully automated so that an operator is notified when an unusual situation or fault is detected. User inputs are through personal computer using mouse and keyboard commands. The graphical user for detecting cryogenic leaks, many other gas constituents could be monitored using the Hazardous Gas Detection System (HGDS) 2000.

  18. System design of the CRISM (compact reconnaissance imaging spectrometer for Mars) hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Silverglate, Peter R.; Fort, Dennis E.

    2004-01-01

    CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) is a hyperspectral imager that will be launched on the MRO (Mars Reconnaissance Orbiter) in August 2005. The MRO will circle Mars in a polar orbit at a nominal altitude of 325 km. The CRISM spectral range spans the ultraviolet (UV) to the mid-wave infrared (MWIR), 400 nm to 4050 nm. The instrument utilizes a Ritchey-Chretien telescope with a 2.06º field of view (FOV) to focus light on the entrance slit of a dual spectrometer. Within the spectrometer light is split by a dichroic into VNIR (visible-near infrared) (λ <= 1.05 μm) and IR (infrared) (λ >= 1.05 μm) beams. Each beam is directed into a separate modified Offner spectrometer that focuses a spectrally dispersed image of the slit onto a two dimensional focal plane (FP). The IR FP is a 640 x 480 HgCdTe area array; the VNIR FP is a 640 x 480 silicon photodiode area array. The spectral image is contiguously sampled with a 6.55 nm spectral spacing and an instantaneous field of view of 60 μradians. The orbital motion of the MRO pushbroom scans the spectrometer slit across the Martian surface, allowing the planet to be mapped in 558 spectral bands. There are four major mapping modes: A quick initial multi-spectral mapping of a major portion of the Martian surface in 59 selected spectral bands at a spatial resolution of 600 μradians (10:1 binning); an extended multi-spectral mapping of the entire Martian surface in 59 selected spectral bands at a spatial resolution of 300 μradians (5:1 binning); a high resolution Target Mode, performing hyperspectral mapping of selected targets of interest at full spatial and spectral resolution; and an atmospheric Emission Phase Function (EPF) mode for atmospheric study and correction at full spectral resolution at a spatial resolution of 300 μradians (5:1 binning). The instrument is gimbaled to allow scanning over +/-60° for the EPF and Target modes. The scanning also permits orbital motion compensation, enabling

  19. System design of the CRISM (compact reconnaissance imaging spectrometer for Mars) hyperspectral imager

    NASA Astrophysics Data System (ADS)

    Silverglate, Peter R.; Fort, Dennis E.

    2003-12-01

    CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) is a hyperspectral imager that will be launched on the MRO (Mars Reconnaissance Orbiter) in August 2005. The MRO will circle Mars in a polar orbit at a nominal altitude of 325 km. The CRISM spectral range spans the ultraviolet (UV) to the mid-wave infrared (MWIR), 400 nm to 4050 nm. The instrument utilizes a Ritchey-Chretien telescope with a 2.06º field of view (FOV) to focus light on the entrance slit of a dual spectrometer. Within the spectrometer light is split by a dichroic into VNIR (visible-near infrared) (λ <= 1.05 μm) and IR (infrared) (λ >= 1.05 μm) beams. Each beam is directed into a separate modified Offner spectrometer that focuses a spectrally dispersed image of the slit onto a two dimensional focal plane (FP). The IR FP is a 640 x 480 HgCdTe area array; the VNIR FP is a 640 x 480 silicon photodiode area array. The spectral image is contiguously sampled with a 6.55 nm spectral spacing and an instantaneous field of view of 60 μradians. The orbital motion of the MRO pushbroom scans the spectrometer slit across the Martian surface, allowing the planet to be mapped in 558 spectral bands. There are four major mapping modes: A quick initial multi-spectral mapping of a major portion of the Martian surface in 59 selected spectral bands at a spatial resolution of 600 μradians (10:1 binning); an extended multi-spectral mapping of the entire Martian surface in 59 selected spectral bands at a spatial resolution of 300 μradians (5:1 binning); a high resolution Target Mode, performing hyperspectral mapping of selected targets of interest at full spatial and spectral resolution; and an atmospheric Emission Phase Function (EPF) mode for atmospheric study and correction at full spectral resolution at a spatial resolution of 300 μradians (5:1 binning). The instrument is gimbaled to allow scanning over +/-60° for the EPF and Target modes. The scanning also permits orbital motion compensation, enabling

  20. Transient dispersion and absorption in a V-shaped atomic system

    NASA Astrophysics Data System (ADS)

    Sahrai, M.; Maleki, A.; Hemmati, R.; Mahmoudi, M.

    2010-01-01

    We investigate the dynamical behavior of the dispersion and the absorption in a V-type three level atomic system. It is shown that in the presence of decay-induced interference the probe dispersion and absorption are phase dependent. We find that an incoherent pumping field provides an additional control parameter for switching the group velocity of a light pulse. The required switching times for switching the group velocity of a probe field from subluminal to superluminal pulse propagation is then discussed.

  1. Ultra-Wideband Optical Modulation Spectrometer (OMS) Development

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan (Technical Monitor); Tolls, Volker

    2004-01-01

    The optical modulation spectrometer (OMS) is a novel, highly efficient, low mass backend for heterodyne receiver systems. Current and future heterodyne receiver systems operating at frequencies up to a few THz require broadband spectrometer backends to achieve spectral resolutions of R approximately 10(exp 5) to 10(exp 6) to carry out many important astronomical investigations. Among these are observations of broad emission and absorption lines from extra-galactic objects at high redshifts, spectral line surveys, and observations of planetary atmospheres. Many of these lines are pressure or velocity broadened with either large half-widths or line wings extending over several GHz. Current backend systems can cover the needed bandwidth only by combining the output of several spectrometers, each with typically up to 1 GHz bandwidth, or by combining several frequency-shifted spectra taken with a single spectrometer. An ultra-wideband optical modulation spectrometer with 10 - 40 GHz bandwidth will enable broadband ob- servations without the limitations and disadvantages of hybrid spectrometers. Spectrometers like the OMS will be important for both ground-based observatories and future space missions like the Single Aperture Far-Infrared Telescope (SAFIR) which might carry IR/submm array heterodyne receiver systems requiring a spectrometer for each array pixel. Small size, low mass and small power consumption are extremely important for space missions. This report summarizes the specifications developed for the OMS and lists already identified commercial parts. The report starts with a review of the principle of operation, then describes the most important components and their specifications which were derived from theory, and finishes with a conclusion and outlook.

  2. Electrospray Ionization/Ion Mobility Spectrometer/Cylindrical Ion Trap Mass Spectrometer System for In-Situ Detection of Organic Compounds

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Johnson, P. V.; Beegle, L. W.; Cooks, R. G.; Laughlin, B. C.; Hill, H. H.

    2003-01-01

    The potential of an Electrospray Ionization/Ion Mobility Spectrometer/Cylindrical Ion Trap Mass Spectrometer (ESI/IMS/CIT-MS) as an analytical instrument for analyzing material extracted from rock and soil samples as part of a suite of instruments on the proposed 2009 Mars Science Lander (MSL) will be demonstrated. This instrument will be able to identify volatile compounds as well as resident organic molecules on the parts-per-billion (ppb) level. Also, it will be able to obtain an inventory of chemical species on the surface of Mars which will result in a better understanding of ongoing surface chemistry. Finally, questions relevant to biological processes will be answered with the complete inventory of surface and near surface organic molecules that the ESI/IMS/CIT is capable of performing.

  3. [The Research for Trace Ammonia Escape Monitoring System Based on Tunable Diode Laser Absorption Spectroscopy].

    PubMed

    Zhang, Li-fang; Wang, Fei; Yu, Li-bin; Yan, Jian-hua; Cen, Ke-fa

    2015-06-01

    In order to on-line measure the trace ammonia slip of the commercial power plant in the future, this research seeks to measure the trace ammonia by using tunable diode laser absorption spectroscopy under ambient temperature and pressure, and at different temperatures, and the measuring temperature is about 650 K in the power plant. In recent years lasers have become commercially available in the near-infrared where the transitions are much stronger, and ammonia's spectroscopy is pretty complicated and the overlapping lines are difficult to resolve. A group of ammonia transitions near 4 433.5 cm(-1) in the v2 +v3 combination band have been thoroughly selected for detecting lower concentration by analyzing its absorption characteristic and considering other absorption interference in combustion gases where H2O and CO2 mole fraction are very large. To illustrate the potential for NH3 concentration measurements, predictions for NH3, H2O and CO2 are simultaneously simulated, NH3 absorption lines near 4 433.5 cm(-1) wavelength meet weaker H2O absorption than the commercial NH3 lines, and there is almost no CO2 absorption, all the parameters are based on the HITRAN database, and an improved detection limit was obtained for interference-free NH3 monitoring, this 2.25 μm band has line strengths several times larger than absorption lines in the 1.53 μm band which was often used by NH3 sensors for emission monitoring and analyzing. The measurement system was developed with a new Herriott cell and a heated gas cell realizing fast absorption measurements of high resolution, and combined with direct absorption and wavelenguh modulation based on tunable diode laser absorption spectroscopy at different temperatures. The lorentzian line shape is dominant at ambient temperature and pressure, and the estimated detectivity is approximately 0.225 x 10(-6) (SNR = 1) for the directed absorption spectroscopy, assuming a noise-equivalent absorbance of 1 x 10(-4). The heated cell

  4. Load-limiting landing gear footpad energy absorption system

    NASA Technical Reports Server (NTRS)

    Hansen, Chris; Tsai, Ted

    1994-01-01

    As a precursor to future manned missions to the moon, an inexpensive, unmanned vehicle that could carry small, scientific payloads to the lunar surface was studied by NASA. The vehicle, called the Common Lunar Lander, required extremely optimized structural systems to increase the potential payload mass. A lightweight energy-absorbing system (LAGFEAS), which also acts as a landing load-limiter was designed to help achieve this optimized structure. Since the versatile and easily tailored system is a load-limiter, it allowed for the structure to be designed independently of the ever-changing landing energy predictions. This paper describes the LAGFEAS system and preliminary verification testing performed at NASA's Johnson Space Center for the Common Lunar Lander program.

  5. Surface Plasmon Based Spectrometer

    NASA Astrophysics Data System (ADS)

    Wig, Andrew; Passian, Ali; Boudreaux, Philip; Ferrell, Tom

    2008-03-01

    A spectrometer that uses surface plasmon excitation in thin metal films to separate light into its component wavelengths is described. The use of surface plasmons as a dispersive medium sets this spectrometer apart from prism, grating, and interference based variants and allows for the miniaturization of this device. Theoretical and experimental results are presented for two different operation models. In the first case surface plasmon tunneling in the near field is used to provide transmission spectra of different broad band-pass, glass filters across the visible wavelength range with high stray-light rejection at low resolution as well as absorption spectra of chlorophyll extracted from a spinach leaf. The second model looks at the far field components of surface plasmon scattering.

  6. Optimal extraction of quasar Lyman limit absorption systems from the IUE archive

    NASA Technical Reports Server (NTRS)

    Tytler, David

    1992-01-01

    The IUE archive contains a wealth of information on Lyman limit absorption systems (LLS) in quasar spectra. QSO spectra from the IUE data base were optimally extracted, coadded, and analyzed to yield a homogeneous samples of LLS at low red shifts. This sample comprise 36 LLS, twice the number previously analyzed low z samples. These systems are ideal for the determination of the origin, redshift evolution, ionization, velocity dispersions and the metal abundances of absorption systems. Two of them are also excellent targets for the primordial Deuterium to Hydrogen ratio.

  7. Radiation absorption by the C2 band systems for Jupiter entry conditions

    NASA Technical Reports Server (NTRS)

    Sutton, K.; Moss, J. N.

    1979-01-01

    Revised values of the absorption cross sections for seven electronic band systems of C2 have been calculated using recently published experimental data for the electronic transition moments. Using these revised C2 cross section values, computations were made for the radiating flow field over a Jupiter entry probe with coupled ablation injection from a carbon-phenolic heat shield. Results are presented which show that radiation absorption within the ablation layer for the spectral range of 4 to 6 eV is less than that predicted using previous C2 absorption cross section values. The effect of the reduced radiation absorption by the C2 molecule is an increase in the radiative heating rates and ablation mass loss rates for the Jupiter entry conditions considered in the study.

  8. Analysis of a solar heat pipe heating and absorption cooling system

    NASA Astrophysics Data System (ADS)

    Munje, S. R.

    A new concept which combines a flat-plate heat-pipe solar collector for daytime solar water heating by evaporation of a refrigerant and night-time water chilling by absorption refrigeration was analyzed. A comprehensive survey of literature was completed to establish the existing state of knowledge on intermittent absorption refrigeration, flat-plate solar heat collectors and night sky radiation cooling. The literature survey showed that the idea of using a passive device such as a heat pipe with the absorption refrigeration principle for both heating and cooling is relatively new. A mathematical model for the heat-pipe flat-plate collector and the absorption refrigeration process was developed. A cost-effectiveness study was also carried out to find the optimum thickness of the collector plate. The optimum plate thickness was used in the parametric study of the system.

  9. Multiaperture Spectrometer

    NASA Technical Reports Server (NTRS)

    Schindler, Rudolf A.; Pagano, Robert J.; O'Callaghan, Fred G.

    1991-01-01

    Proposed multiaperture spectrometer containing single grating provides high spectral resolution over broad spectrum. Produces parallel line images, each of which highly spectrally resolved display of intensity vs. wavelength in wavelength band of one of orders of spectrum produced by grating. Advantages; convenient two-dimensional spectral image, fewer components, and greater efficiency.

  10. Spectrometer gun

    DOEpatents

    Waechter, David A.; Wolf, Michael A.; Umbarger, C. John

    1985-01-01

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  11. Spectrometer gun

    DOEpatents

    Waechter, D.A.; Wolf, M.A.; Umbarger, C.J.

    1981-11-03

    A hand-holdable, battery-operated, microprocessor-based spectrometer gun is described that includes a low-power matrix display and sufficient memory to permit both real-time observation and extended analysis of detected radiation pulses. Universality of the incorporated signal processing circuitry permits operation with various detectors having differing pulse detection and sensitivity parameters.

  12. Measurements of serum glucose using the luciferin/Luciferase system and a liquid scintillation spectrometer

    SciTech Connect

    Idahl, L.A.; Sandstroem, P.E.; Sehlin, J.

    1986-05-15

    A single-step assay for serum glucose measurements is described. The assay is based on the phosphorylation of D-glucose by glucokinase and the measurement of ATP consumption by firefly luciferase. The luminescence is recorded in an ordinary liquid scintillation spectrometer. The use of stable reagents and a stable final signal (light emission) makes it possible to analyze a large number of samples in each assay run. The assay is of particular value when repeated serum glucose determinations are performed on samples from small laboratory animals.

  13. High sensitivity pulse-counting mass spectrometer system for noble gas analysis

    NASA Technical Reports Server (NTRS)

    Hohenberg, C. M.

    1980-01-01

    A pulse-counting mass spectrometer is described which is comprised of a new ion source of cylindrical geometry, with exceptional optical properties (the Baur source), a dual focal plane externally adjustable collector slits, and a 17-stage Allen-type electron multiplier, all housed in a metal 21 cm radius, 90 deg magnetic sector flight tube. Mass discrimination of the instrument is less than 1 per mil per mass unit; the optical transmission is more than 90%; the source sensitivity (Faraday collection) is 4 ma/torr at 250 micron emission; and the abundance sensitivity is 30,000.

  14. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

    NASA Technical Reports Server (NTRS)

    Macenka, Steven A.; Chrisp, Michael P.

    1988-01-01

    The development of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been completed at JPL. This paper outlines the functional requirements of the spectrometer optics subsystem, and describes the spectrometer optical design. The optical subsystem performance is shown in terms of spectral modulation transfer functions, radial energy distributions, and system transmission at selected wavelengths for the four spectrometers. An outline of the spectrometer alignment is included.

  15. A colloidal quantum dot spectrometer

    NASA Astrophysics Data System (ADS)

    Bao, Jie; Bawendi, Moungi G.

    2015-07-01

    Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturized, cheap and easy-to-use systems. Current microspectrometer designs mostly use interference filters and interferometric optics that limit their photon efficiency, resolution and spectral range. Here we show that many of these limitations can be overcome by replacing interferometric optics with a two-dimensional absorptive filter array composed of colloidal quantum dots. Instead of measuring different bands of a spectrum individually after introducing temporal or spatial separations with gratings or interference-based narrowband filters, a colloidal quantum dot spectrometer measures a light spectrum based on the wavelength multiplexing principle: multiple spectral bands are encoded and detected simultaneously with one filter and one detector, respectively, with the array format allowing the process to be efficiently repeated many times using different filters with different encoding so that sufficient information is obtained to enable computational reconstruction of the target spectrum. We illustrate the performance of such a quantum dot microspectrometer, made from 195 different types of quantum dots with absorption features that cover a spectral range of 300 nanometres, by measuring shifts in spectral peak positions as small as one nanometre. Given this performance, demonstrable avenues for further improvement, the ease with which quantum dots can be processed and integrated, and their numerous finely tuneable bandgaps that cover a broad spectral range, we expect that quantum dot microspectrometers will be useful in applications where minimizing size, weight, cost and complexity of the spectrometer are critical.

  16. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1993-12-01

    A-prototype explosives detection system that was developed for experimental evaluation of a nuclear resonance absorption techniques is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection- alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  17. THE STANDARD CALIBRATION INSTRUMENT AUTOMATION SYSTEM FOR THE ATOMIC ABSORPTION SPECTROPHOTOMETER. PART I: FUNCTIONAL SPECIFICATIONS

    EPA Science Inventory

    This document contains a project definition, a set of functional requirements, and a functional design for the automation of flameless atomic absorption (AA) spectrophotometers. The system is a real-time data acquisition system with 'on line' data reduction, quality control and r...

  18. Prototype explosives-detection system based on nuclear-resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1994-06-01

    A prototype explosives-detection system (EDS) that was developed for experimental evaluation of a nuclear-resonance absorption technique is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  19. Infrared absorption of methanethiol clusters (CH3SH)n, n = 2-5, recorded with a time-of-flight mass spectrometer using IR depletion and VUV ionization

    NASA Astrophysics Data System (ADS)

    Fu, Lung; Han, Hui-Ling; Lee, Yuan-Pern

    2012-12-01

    We investigated IR spectra in the CH- and SH-stretching regions of size-selected methanethiol clusters, (CH3SH)n with n = 2-5, in a pulsed supersonic jet using infrared (IR)-vacuum ultraviolet (VUV) ionization. VUV emission at 132.50 nm served as the source of ionization in a time-of-flight mass spectrometer. Clusters were dissociated with light from a tunable IR laser before ionization. The variations in intensity of methanethiol cluster ions (CH3SH)n+ were monitored as the IR laser light was tuned across the range 2470-3100 cm-1. In the SH-stretching region, the spectrum of (CH3SH)2 shows a weak band near 2601 cm-1, red-shifted only 7 cm-1 from that of the monomer. In contrast, all spectra of (CH3SH)n, n = 3-5, show a broad band near 2567 cm-1 with much greater intensity. In the CH-stretching region, absorption bands of (CH3SH)2 are located near 2865, 2890, 2944, and 3010 cm-1, red-shifted by 3-5 cm-1 from those of CH3SH. These red shifts increase slightly for larger clusters and bands near 2856, 2884, 2938, and 3005 cm-1 were observed for (CH3SH)5. These spectral results indicate that the S-H...S hydrogen bond plays an important role in clusters with n = 3-5, but not in (CH3SH)2, in agreement with theoretical predictions. The absence of a band near 2608 cm-1 that corresponds to absorption of the non-hydrogen-bonded SH moiety and the large width of observed feature near 2567 cm-1 indicate that the dominant stable structures of (CH3SH)n, n = 3-5, have a cyclic hydrogen-bonded framework.

  20. Mass spectrometer for quantification and characterization of DNA damage in mammalian and human systems. Final report

    SciTech Connect

    1997-12-31

    The instrument grant was used to purchase a Finnigan TSQ 7000 tandem quadruple mass spectrometer with electrospray and atmospheric-pressure chemical-ionization ion sources for the amount of the grant, $371,857. MIT contributed $50,000 in refurbishing costs for the laboratory in which the instrument is used. This mass spectrometer has been in operation since July, 1995 in professor Steven Tannenbaum`s Laboratory in the MIT Division of Toxicology, under the direct supervision of Dr. John S. Wishnok. Its current location is in MIT Building 56, room 747. It is in good operating condition, and is being actively used. Since the original purchase, the instrument has been upgraded by the addition of a (1) dedicated high-performance liquid chromatograph with an autosampler and (2) a nanoelectrospray ion source. The instrument has been used in a number of research projects including the identification of proteins and oligonucleotides, identification of PAH-DNA and PAH-protein adducts, quantitation of food-related carcinogens, and characterization of nitric oxide- and peroxynitrite-related DNA damage.

  1. The effect of the earth's and stray magnetic fields on mobile mass spectrometer systems.

    PubMed

    Bell, Ryan J; Davey, Nicholas G; Martinsen, Morten; Short, R Timothy; Gill, Chris G; Krogh, Erik T

    2015-02-01

    Development of small, field-portable mass spectrometers has enabled a rapid growth of in-field measurements on mobile platforms. In such in-field measurements, unexpected signal variability has been observed by the authors in portable ion traps with internal electron ionization. The orientation of magnetic fields (such as the Earth's) relative to the ionization electron beam trajectory can significantly alter the electron flux into a quadrupole ion trap, resulting in significant changes in the instrumental sensitivity. Instrument simulations and experiments were performed relative to the earth's magnetic field to assess the importance of (1) nonpoint-source electron sources, (2) vertical versus horizontal electron beam orientation, and (3) secondary magnetic fields created by the instrument itself. Electron lens focus effects were explored by additional simulations, and were paralleled by experiments performed with a mass spectrometer mounted on a rotating platform. Additionally, magnetically permeable metals were used to shield (1) the entire instrument from the Earth's magnetic field, and (2) the electron beam from both the Earth's and instrument's magnetic fields. Both simulation and experimental results suggest the predominant influence on directionally dependent signal variability is the result of the summation of two magnetic vectors. As such, the most effective method for reducing this effect is the shielding of the electron beam from both magnetic vectors, thus improving electron beam alignment and removing any directional dependency. The improved ionizing electron beam alignment also allows for significant improvements in overall instrument sensitivity. PMID:25527328

  2. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-05-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  3. Intestinal triacylglycerol synthesis in fat absorption and systemic energy metabolism.

    PubMed

    Yen, Chi-Liang Eric; Nelson, David W; Yen, Mei-I

    2015-03-01

    The intestine plays a prominent role in the biosynthesis of triacylglycerol (triglyceride; TAG). Digested dietary TAG is repackaged in the intestine to form the hydrophobic core of chylomicrons, which deliver metabolic fuels, essential fatty acids, and other lipid-soluble nutrients to the peripheral tissues. By controlling the flux of dietary fat into the circulation, intestinal TAG synthesis can greatly impact systemic metabolism. Genes encoding many of the enzymes involved in TAG synthesis have been identified. Among TAG synthesis enzymes, acyl-CoA:monoacylglycerol acyltransferase 2 and acyl-CoA:diacylglycerol acyltransferase (DGAT)1 are highly expressed in the intestine. Their physiological functions have been examined in the context of whole organisms using genetically engineered mice and, in the case of DGAT1, specific inhibitors. An emerging theme from recent findings is that limiting the rate of TAG synthesis in the intestine can modulate gut hormone secretion, lipid metabolism, and systemic energy balance. The underlying mechanisms and their implications for humans are yet to be explored. Pharmacological inhibition of TAG hydrolysis in the intestinal lumen has been employed to combat obesity and associated disorders with modest efficacy and unwanted side effects. The therapeutic potential of inhibiting specific enzymes involved in intestinal TAG synthesis warrants further investigation. PMID:25231105

  4. Intestinal triacylglycerol synthesis in fat absorption and systemic energy metabolism

    PubMed Central

    Yen, Chi-Liang Eric; Nelson, David W.; Yen, Mei-I

    2015-01-01

    The intestine plays a prominent role in the biosynthesis of triacylglycerol (triglyceride; TAG). Digested dietary TAG is repackaged in the intestine to form the hydrophobic core of chylomicrons, which deliver metabolic fuels, essential fatty acids, and other lipid-soluble nutrients to the peripheral tissues. By controlling the flux of dietary fat into the circulation, intestinal TAG synthesis can greatly impact systemic metabolism. Genes encoding many of the enzymes involved in TAG synthesis have been identified. Among TAG synthesis enzymes, acyl-CoA:monoacylglycerol acyltransferase 2 and acyl-CoA:diacylglycerol acyltransferase (DGAT)1 are highly expressed in the intestine. Their physiological functions have been examined in the context of whole organisms using genetically engineered mice and, in the case of DGAT1, specific inhibitors. An emerging theme from recent findings is that limiting the rate of TAG synthesis in the intestine can modulate gut hormone secretion, lipid metabolism, and systemic energy balance. The underlying mechanisms and their implications for humans are yet to be explored. Pharmacological inhibition of TAG hydrolysis in the intestinal lumen has been employed to combat obesity and associated disorders with modest efficacy and unwanted side effects. The therapeutic potential of inhibiting specific enzymes involved in intestinal TAG synthesis warrants further investigation. PMID:25231105

  5. One- and two-photon absorption of a spiropyran-merocyanine system: experimental and theoretical studies.

    PubMed

    Matczyszyn, Katarzyna; Olesiak-Banska, Joanna; Nakatani, Keitaro; Yu, Pei; Murugan, N Arul; Zaleśny, Robert; Roztoczyńska, Agnieszka; Bednarska, Joanna; Bartkowiak, Wojciech; Kongsted, Jacob; Ågren, Hans; Samoć, Marek

    2015-01-29

    We report on the nonlinear optical properties measurements and quantum-chemical calculations of a well-known photochromic system consisting of spiropyran and the merocyanine photoproduct. The study of nonlinear absorption and refraction properties of the molecules dissolved in chloroform were performed with the Z-scan technique, using femtosecond pulses in a wide range of wavelengths. Maxima in the two-photon absorption spectrum at 700 and 1050 nm were found for the merocyanine form, and the corresponding two-photon absorption cross section is 80 GM and 20 GM, respectively. The latter feature does not vanish completely in the nonlinear spectrum of the spiropyran form, possibly because of the existence of some photoconversion caused by the laser beam during the measurements. A nonlinear absorption peak at 900 nm is found in the spiropyran form with an effective cross section of about 20 GM; it is likely due to three-photon absorption or to absorption by some intermediate species. The experimental data are supported by calculations performed with the use of a hybrid quantum mechanics-molecular mechanics approach. PMID:25531561

  6. The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029--Ejected or Intervening?

    NASA Technical Reports Server (NTRS)

    Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.

    1996-01-01

    We report the discovery of a high-ionization broad absorption line system at a redshift of z(sub abs) = 0.695 in the spectrum of the z(sub em) = 1.052 radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000 to 5000 km/s is detected from C iv, N v, and O vi in Hubble Space Telescope (HST) Faint Object Spectrograph spectra of the quasar. A narrow-line system (FWHM approx. 250 km/s) at z(sub abs) = 0.7016 is resolved from the broad blend and includes absorption by Ly alpha and the C iv, N v, and O vi doublets. No absorption by low-ionization metal species (e.g., Si II and Mg II) is detected in the HST or ground-based spectra for either the broad or the narrow system. The centroids of the broad system lines are displaced by approx. 56,000 km/s to the blue of the quasar's broad emission lines. The reddest extent of the broad-line absorption is more than 50,000 km/s from the quasar. The properties of this system are unprecedented, whether it is an intervening or an ejected system.

  7. Observations in the Saturn system during approach and orbital insertion, with Cassini's visual and infrared mapping spectrometer (VIMS)

    USGS Publications Warehouse

    Brown, R.H.; Baines, K.H.; Bellucci, G.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Formisano, V.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, C.; Baugh, N.; Griffith, C.A.; Hansen, G.B.; Hibbitts, C.A.; Momary, T.W.; Showalter, M.R.

    2006-01-01

    The Visual and Infrared Mapping Spectrometer observed Phoebe, Iapetus, Titan and Saturn's rings during Cassini's approach and orbital insertion. Phoebe's surface contains water ice, CO2, and ferrous iron. lapetus contains CO2 and organic materials. Titan's atmosphere shows methane fluorescence, and night-side atmospheric emission that may be CO2 and CH3D. As determined from cloud motions, the winds at altitude 25-30 km in the south polar region of Titan appear to be moving in a prograde direction at velocity ???1 m s-1. Circular albedo features on Titan's surface, seen at 2.02 ??m, may be palimpsests remaining from the rheological adjustment of ancient impact craters. As such, their long-term persistence is of special interest in view of the expected precipitation of liquids and solids from the atmosphere. Saturn's rings have changed little in their radial structure since the Voyager flybys in the early 1980s. Spectral absorption bands tentatively attributed to Fe2+ suggest that iron-bearing silicates are a source of contamination of the C ring and the Cassini Division. ?? ESO 2006.

  8. Magellan LDSS3 emission confirmation of galaxies hosting metal-rich Lyman α absorption systems

    NASA Astrophysics Data System (ADS)

    Straka, Lorrie A.; Johnson, Sean; York, Donald G.; Bowen, David V.; Florian, Michael; Kulkarni, Varsha P.; Lundgren, Britt; Péroux, Celine

    2016-06-01

    Using the Low Dispersion Survey Spectrograph 3 at the Magellan II Clay Telescope, we target candidate absorption host galaxies detected in deep optical imaging (reaching limiting apparent magnitudes of 23.0-26.5 in g, r, i, and z filters) in the fields of three QSOs, each of which shows the presence of high metallicity, high N_{H I} absorption systems in their spectra (Q0826-2230: zabs = 0.9110, Q1323-0021: zabs = 0.7160, Q1436-0051: zabs = 0.7377, 0.9281). We confirm three host galaxies at redshifts 0.7387, 0.7401, and 0.9286 for two of the Lyman α absorption systems (one with two galaxies interacting). For these systems, we are able to determine the star formation rates (SFRs); impact parameters (from previous imaging detections); the velocity shift between the absorption and emission redshifts; and, for one system, also the emission metallicity. Based on previous photometry, we find these galaxies have L > L*. The [O II] SFRs for these galaxies are in the range 11-25 M⊙ yr-1 (uncorrected for dust), while the impact parameters lie in the range 35-54 kpc. Despite the fact that we have confirmed galaxies at 50 kpc from the QSO, no gradient in metallicity is indicated between the absorption metallicity along the QSO line of sight and the emission line metallicity in the galaxies. We confirm the anticorrelation between impact parameter and N_{H I} from the literature. We also report the emission redshift of five other galaxies: three at zem > zQSO, and two (L < L*) at zem < zQSO not corresponding to any known absorption systems.

  9. Transient Heavy Element Absorption Systems in Novae: Episodic Mass Ejection from the Secondary Star

    NASA Astrophysics Data System (ADS)

    Williams, Robert; Mason, Elena; Della Valle, Massimo; Ederoclite, Alessandro

    2008-09-01

    A high-resolution spectroscopic survey of post-outburst novae reveals short-lived heavy element absorption systems in a majority of novae near maximum light, having expansion velocities of 400-1000 km s-1 and velocity dispersions between 35 and 350 km s-1. A majority of systems are accelerated outward, and they all progressively weaken and disappear over timescales of weeks. A few of the systems having narrow, deeper absorption reveal a rich spectrum of singly ionized Sc, Ti, V, Cr, Fe, Sr, Y, Zr, and Ba lines. Analysis of the richest such system, in LMC 2005, shows the excitation temperature to be 104 K and elements lighter than Fe to have abundance enhancements over solar values by up to an order of magnitude. The gas causing the absorption systems must be circumbinary and its origin is most likely mass ejection from the secondary star. The absorbing gas exists before the outburst and may represent episodic mass transfer events from the secondary star that initiate the nova outburst(s). If SNe Ia originate in single degenerate binaries, such absorption systems could be detectable before maximum light.

  10. On-Chip Micro-Electro-Mechanical System Fourier Transform Infrared (MEMS FT-IR) Spectrometer-Based Gas Sensing.

    PubMed

    Erfan, Mazen; Sabry, Yasser M; Sakr, Mohammad; Mortada, Bassem; Medhat, Mostafa; Khalil, Diaa

    2016-05-01

    In this work, we study the detection of acetylene (C2H2), carbon dioxide (CO2) and water vapor (H2O) gases in the near-infrared (NIR) range using an on-chip silicon micro-electro-mechanical system (MEMS) Fourier transform infrared (FT-IR) spectrometer in the wavelength range 1300-2500 nm (4000-7692 cm(-1)). The spectrometer core engine is a scanning Michelson interferometer micro-fabricated using a deep-etching technology producing self-aligned components. The light is free-space propagating in-plane with respect to the silicon chip substrate. The moving mirror of the interferometer is driven by a relatively large stroke electrostatic comb-drive actuator corresponding to about 30 cm(-1) resolution. Multi-mode optical fibers are used to connect light between the wideband light source, the interferometer, the 10 cm gas cell, and the optical detector. A wide dynamic range of gas concentration down to 2000 parts per million (ppm) in only 10 cm length gas cell is demonstrated. Extending the wavelength range to the mid-infrared (MIR) range up to 4200 nm (2380 cm(-1)) is also experimentally demonstrated, for the first time, using a bulk micro-machined on-chip MEMS FT-IR spectrometer. The obtained results open the door for an on-chip optical gas sensor for many applications including environmental sensing and industrial process control in the NIR/MIR spectral ranges. PMID:27044847

  11. Electron-proton spectrometer

    NASA Technical Reports Server (NTRS)

    Winckler, J. R.

    1973-01-01

    An electron-proton spectrometer was designed to measure the geomagnetically trapped radiation in a geostationary orbit at 6.6 earth radii in the outer radiation belt. This instrument is to be flown on the Applications Technology Satellite-F (ATS-F). The electron-proton spectrometer consists of two permanent magnet surface barrier detector arrays and associated electronics capable of selecting and detecting electrons in three energy ranges: (1) 30-50 keV, (2) 150-200 keV, and (3) 500 keV and protons in three energy ranges. The electron-proton spectrometer has the capability of measuring the fluxes of electrons and protons in various directions with respect to the magnetic field lines running through the satellite. One magnet detector array system is implemented to scan between EME north and south through west, sampling the directional flux in 15 steps. The other magnet-detector array system is fixed looking toward EME east.

  12. The Spectrometer

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2012-01-01

    In the fall of 1999 I was shown an Ocean Optics spectrometer-in-the-computer at St. Patricks College at Maynooth, Ireland, and thought that I had seen heaven. Of course, it could not resolve the sodium D-lines (I had done that many years before with a homemade wire diffraction grating), and I began to realize that inside was some familiar old…

  13. System for studying a sample of material using a heavy ion induced mass spectrometer source

    DOEpatents

    Fries, D.P.; Browning, J.F.

    1998-07-21

    A heavy ion generator is used with a plasma desorption mass spectrometer to provide an appropriate neutron flux in the direction of a fissionable material in order to desorb and ionize large molecules from the material for mass analysis. The heavy ion generator comprises a fissionable material having a high (n,f) reaction cross section. The heavy ion generator also comprises a pulsed neutron generator that is used to bombard the fissionable material with pulses of neutrons, thereby causing heavy ions to be emitted from the fissionable material. These heavy ions impinge on a material, thereby causing ions to desorb off that material. The ions desorbed off the material pass through a time-of-flight mass analyzer, wherein ions can be measured with masses greater than 25,000 amu. 3 figs.

  14. System for studying a sample of material using a heavy ion induced mass spectrometer source

    DOEpatents

    Fries, David P.; Browning, James F.

    1998-01-01

    A heavy ion generator is used with a plasma desorption mass spectrometer to provide an appropriate neutron flux in the direction of a fissionable material in order to desorb and ionize large molecules from the material for mass analysis. The heavy ion generator comprises a fissionable material having a high n,f reaction cross section. The heavy ion generator also comprises a pulsed neutron generator that is used to bombard the fissionable material with pulses of neutrons, thereby causing heavy ions to be emitted from the fissionable material. These heavy ions impinge on a material, thereby causing ions to desorb off that material. The ions desorbed off the material pass through a time-of-flight mass analyzer, wherein ions can be measured with masses greater than 25,000 amu.

  15. LiCl dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

    SciTech Connect

    Ko, S.M.

    1980-06-03

    This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system. 4 figs.

  16. LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

    DOEpatents

    Ko, Suk M.

    1980-01-01

    This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

  17. Accurate universal parameterization of absorption cross sections III--light systems

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Cucinotta, F. A.; Wilson, J. W.

    1999-01-01

    Our prior nuclear absorption cross sections model [R.K. Tripathi, F.A. Cucinotta, J.W. Wilson, Nucl. Instr. and Meth. B 117 (1996) 347; R.K. Tripathi, J.W. Wilson, F.A. Cucinotta, Nucl. Instr. and Meth. B 129 (1997) 11] is extended for light systems (A < or = 4) where either both projectile and target are light particles or one is light particle and the other is medium or heavy nucleus. The agreement with experiment is excellent for these cases as well. Present work in combination with our original model provides a comprehensive picture of absorption cross sections for light, medium and heavy systems. As a result the extended model can reliably be used in all studies where there is a need for absorption cross sections.

  18. Real-time atmospheric absorption spectra for in-flight tuning of an airborne dial system

    NASA Technical Reports Server (NTRS)

    Dombrowski, M.; Walden, H.; Schwemmer, G. K.; Milrod, J.; Korb, C. L.

    1986-01-01

    Real-time measurements of atmospheric absorption spectra are displayed and used to precisely calibrate and fix the frequency of an Alexandrite laser to specific oxygen absorption features for airborne Differential Absorption Lidar (DIAL) measurements of atmospheric pressure and temperature. The DIAL system used contains two narrowband tunable Alexandrite lasers: one is electronically scanned to tune to oxygen absorption features for on-line signals while the second is used to obtain off-line (nonabsorbed) atmospheric return signals. The lidar operator may select the number of shots to be averaged, the altitude, and altitude interval over which the signals are averaged using single key stroke commands. The operator also determines exactly which oxygen absorption lines are scanned by comparing the line spacings and relative strengths with known line parameters, thus calibrating the laser wavelength readout. The system was used successfully to measure the atmospheric pressure profile on the first flights of this lidar, November 20, and December 9, 1985, aboard the NASA Wallops Electra aircraft.

  19. Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols.

    PubMed

    Higdon, N S; Browell, E V; Ponsardin, P; Grossmann, B E; Butler, C F; Chyba, T H; Mayo, M N; Allen, R J; Heuser, A W; Grant, W B; Ismail, S; Mayor, S D; Carter, A F

    1994-09-20

    An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H(2)O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and > 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H(2)O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H(2)O absorption-line parameters were perfo med to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H(2)O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H(2)O radiosondes. The H(2)O distributions measured with the DIAL system differed by ≤ 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions. PMID:20941181

  20. Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols

    NASA Technical Reports Server (NTRS)

    Carter, Arlen F.; Allen, Robert J.; Mayo, M. Neale; Butler, Carolyn F.; Grossman, Benoist E.; Ismail, Syed; Grant, William B.; Browell, Edward V.; Higdon, Noah S.; Mayor, Shane D.; Ponsardin, Patrick; Hueser, Alene W.

    1994-01-01

    An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H2O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and greater than 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H2O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H2O absorption-line parameters were performed to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H2O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H2O radiosondes. The H2O distributions measured with the DIAL system differed by less than 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions.

  1. INCIDENCE OF Mg II ABSORPTION SYSTEMS TOWARD FLAT-SPECTRUM RADIO QUASARS

    SciTech Connect

    Chand, Hum; Gopal-Krishna E-mail: krishna@ncra.tifr.res.in

    2012-07-20

    The conventional wisdom that the rate of incidence of Mg II absorption systems, dN/dz (excluding 'associated systems' having a velocity {beta}c relative to the active galactic nucleus (AGN) of less than {approx}5000 km s{sup -1}), is totally independent of the background AGNs has been challenged by a recent finding that dN/dz for strong Mg II absorption systems toward distant blazars is 2.2 {+-} {sup 0.8}{sub 0.6} times the value known for normal optically selected quasars (QSOs). This has led to the suggestion that a significant fraction of even the absorption systems with {beta} as high as {approx}0.1 may have been ejected by the relativistic jets in the blazars, which are expected to be pointed close to our direction. Here, we investigate this scenario using a large sample of 115 flat-spectrum radio-loud quasars (FSRQs) that also possess powerful jets, but are only weakly polarized. We show, for the first time, that dN/dz toward FSRQs is, on the whole, quite similar to that known for QSOs and that the comparative excess of strong Mg II absorption systems seen toward blazars is mainly confined to {beta} < 0.15. The excess relative to FSRQs probably results from a likely closer alignment of blazar jets with our direction; hence, any gas clouds accelerated by them are more likely to be on the line of sight to the active quasar nucleus.

  2. Design of onboard calibration unit of space-borne imaging spectrometer

    NASA Astrophysics Data System (ADS)

    Li, Ming; Ding, Shitao; Xiao, Dazhou

    2014-11-01

    The onboard calibration unit is an important part of the space-borne imaging spectrometer and used for the onboard radiometric calibration and spectral calibration of the spectrometer. An imaging spectrometer used in marine satellite is given as an example and its onboard calibration unit is introduced. The onboard calibration unit is in the front of the optical path of the spectrometer, with the sun as the light source, the space qualified PTFE diffusers are used for the onboard radiometric calibration, and the space qualified PTFE diffuser doped with rare earth elements is used for the onboard spectral calibration. The components of the calibration unit are introduced. For the main radiometric calibration diffuser and the redundant radiometric calibration diffuser, the BDRF test results in component level are introduced. Considering the effects of the assembly error and the stray light after the assembly of the spectrometer, the BDRF test method of the radiometric calibration diffuser in system level is introduced. The test results of the directional hemispherical reflectance of the radiometric calibration diffusers and the spectral calibration diffuser are given and the wavelengths of the absorption peaks of the spectral calibration diffuser are obtained. According to the measurement signal of the spectrometer while the onboard spectral calibration, the wavelengths of the absorption peaks of the spectral calibration diffuser which can be used for the onboard spectral calibration are determined. The onboard calibration unit can satisfy the onboard calibration requirements of the spectrometer.

  3. A nonlinear screen as an element for sound absorption and frequency conversion systems

    NASA Astrophysics Data System (ADS)

    Rudenko, O. V.

    2016-01-01

    The paper discusses a model for a screen with dissipative and nonlinear elastic properties that can be used in acoustic sound absorption and frequency conversion systems. Calculation and estimation schemes are explained that are necessary for understanding the functional capabilities of the device. Examples of the nonlinear elements in the screen and promising applications are described.

  4. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-ray and Gamma-ray Spectrometer (XGRS) Ground System

    NASA Technical Reports Server (NTRS)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  5. Data Processing for the Near Earth Asteroid Rendezvous (NEAR), X-Ray and Gamma-Ray Spectrometer (XRS) Ground System

    NASA Technical Reports Server (NTRS)

    McClanahan, Timothy P.; Mikheeva, I.; Trombka, J. I.; Floyd, S. R.; Boynton, W. V.; Bailey, H.; Bhangoo, J.; Starr, R.; Clark, P. E.; Evans, L. G.

    1999-01-01

    An X-ray and Gamma-ray spectrometer (XGRS) is onboard the Near Earth Asteroid Rendezvous (NEAR) spacecraft to determine the elemental composition of the surface of the asteroid 433Eros. The Eros asteroid is highly non-spherical in physical shape and the development of data management and analysis methodologies are in several areas a divergence from traditional remotely sensed geographical information systems techniques. Field of view and asteroid surface geometry must be derived virtually and then combined with real measurements of solar, spectral and instrument calibration information to derive meaningful scientific results. Spatial resolution of planned geochemical maps will be improved from the initial conditions of low statistical significance per integration by repeated surface flyovers and regional spectral accumulation. This paper describes the results of a collaborative effort of design and development of the NEAR XGRS instrument ground system undertaken by participants at the Goddard Space Flight Center, University of Arizona, Cornell University, Applied Physics Laboratory, and Max Plank institute.

  6. L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser

    PubMed Central

    Mitzner, Rolf; Rehanek, Jens; Kern, Jan; Gul, Sheraz; Hattne, Johan; Taguchi, Taketo; Alonso-Mori, Roberto; Tran, Rosalie; Weniger, Christian; Schröder, Henning; Quevedo, Wilson; Laksmono, Hartawan; Sierra, Raymond G.; Han, Guangye; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Kubicek, Katharina; Schreck, Simon; Kunnus, Kristjan; Brzhezinskaya, Maria; Firsov, Alexander; Minitti, Michael P.; Turner, Joshua J.; Moeller, Stefan; Sauter, Nicholas K.; Bogan, Michael J.; Nordlund, Dennis; Schlotter, William F.; Messinger, Johannes; Borovik, Andrew; Techert, Simone; de Groot, Frank M. F.; Föhlisch, Alexander; Erko, Alexei; Bergmann, Uwe; Yachandra, Vittal K.; Wernet, Philippe; Yano, Junko

    2013-01-01

    L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming O K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples. PMID:24466387

  7. Measurements of (C-12)H4 nu-4 band halfwidths using a tunable diode laser system and a Fourier transform spectrometer

    NASA Technical Reports Server (NTRS)

    Devi, V. M.; Benner, D. C.; Rinsland, C. P.; Smith, M. A. H.

    1985-01-01

    Air-broadened and N2-broadened halfwidths at room temperature for twenty-five transitions in the nu-4 fundamental band of (C-12)H4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250-1380-kayser region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-kayser resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3 percent in most cases.

  8. Systemic absorption of Tc-99m-pertechnetate during dacryoscintigraphy: a note of caution.

    PubMed

    Ayati, Narjess-Khatoon; Malekshahi, Reza Gholami; Zakavi, Seyed Rasoul; Dabbagh Kakhki, Vahid Reza; Aryana, Kamran; Sadeghi, Ramin

    2010-10-01

    We report a 37-year-old patient with the history of bilateral epiphora, who was referred to our department for dacryoscintigraphy imaging. The patient had bilateral obstruction of the lacrimal apparatus at the sac-duct level on the scintigraphy images. Delayed imaging showed Tc-99m pertechnetate uptake in the thyroid due to systemic absorption of the tracer from the conjunctiva. We recommend using tracers with large particle size and lower possibility of mucosal absorption for dacryoscintigraphy in order to decrease unnecessary thyroid radiation. PMID:20572752

  9. Correlation analysis of optical absorption cross section and rate coefficient measurements in reacting systems

    SciTech Connect

    Hessler, J.P.; Ogren, P.J.

    1992-08-31

    A technique was developed for determining relative importance and correlation between reactions making up a complex kinetic system. This technique was used to investigate measurements of optical absorption cross sections and the correlation between cross sections and measured rate coefficients. It is concluded that (1) species, initial conditions, and temporal regions may be identified where cross sections may be measured without interference from the kinetic behavior of the observed species and (2) experiments designed to measure rate coefficients will always be correlated with the absorption cross section of the observed species. This correlation may reduce the accuracy of rate coefficient measurements.

  10. Portable Instrument to Measure CDOM Light Absorption in Aquatic Systems: WPI Success Story

    NASA Technical Reports Server (NTRS)

    2001-01-01

    World Precision Instruments, Inc. (WPI), of Sarasota, FL, in collaboration with NASA's John C. Stennis Space Center, has developed an innovative instrument to accurately measure Colored Dissolved Organic Matter (CDOM) absorption in the field. This successful collaboration has culminated in an exciting new device, called the UltraPath, now commercially available through WPI. Traditional methods of measuring absorption of dissolved materials require special handling and storage prior to measurement. Use of laboratory spectrophotometers as the measuring devices have proven time consuming, cumbersome, and delicate to handle. The UltraPath provides a low-cost, highly sensitive, rugged, portable system that is capable of high sensitivity measurements in widely divergent waters.

  11. Airborne measurements of CO2 and CH4 onboard the UK FAAM research aircraft using a, Los Gatos Research Inc, cavity enhanced absorption spectrometer

    NASA Astrophysics Data System (ADS)

    O'Shea, S.; Bauguitte, S.; Muller, J. B.; Le Breton, M.; Gallagher, M. W.; Allen, G.; Percival, C. J.

    2012-12-01

    Airborne measurements of CO2 and CH4 have been made using the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft since spring 2011.The measurement system uses a commercially available analyser, based on the off-axis integrated cavity output spectroscopy technique, from Los Gatos Research Inc (FGGA, Model RMT-200). During the first year of operation (29 flights), 1 Hz measurements were found to be accurate to 0.07 ± 2.48ppbv for CH4 and -0.06± 0.66ppmv for CO2. In summer 2011, as part of the BORTAS project (Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites), outflow from boreal forest fires was measured in Eastern Canada. A number of fresh and photochemically-aged plumes were identified using simultaneous HCN measurements, a widely used tracer for biomass burning. In the freshest plumes, strong relationships were found between CH4, CO2 and other tracers for biomass burning. From this we were able to estimate that 6.9±0.8 g of CH4 and 1551±213 g of CO2 were released into the atmosphere per kg of dry matter burnt. These emission factors are in good agreement with estimates from previous studies in boreal regions. However for aged plumes the correlations between CH4 and other biomass burning tracers were not as robust, most likely due to mixing from other CH4 emission sources, such as the wetland regions. The role of additional emission sources will be investigated using the UK Met Office NAME atmospheric dispersion model and the HYSPLIT trajectory model. Using tailored back trajectory analysis, we will present an interpretation of this new dataset in the context of air mass/fire origin, relating this to MODIS fire maps and source strength.

  12. Coherent manipulation of absorption by intense fields in four level ladder system

    NASA Astrophysics Data System (ADS)

    Kumar, Pardeep; Dasgupta, Shubhrangshu

    2016-05-01

    Nonlinear optical processes attributed to the dependence of the susceptibility of the medium on the input fluence can be remarkably manipulated by the quantum interference and coherence. One of these processes, the optical bistability (OB), that refers to the possibilities of two stable outputs for the same input fields, can also be modified by quantum coherence. Further, the nonlinear dependence of the absorption on the power of the input light gives rise to interesting processes like saturable absorption (SA) and reverse saturable absorption (RSA). While the SA corresponds to the decrease in the absorption coefficient with the increase of intensity of input light, the RSA corresponds to otherwise, that finds applications in optical limiting. We show, using a four-level Ladder system, how a control field manipulates these processes for an intense probe field applied in the excited state transition. The nonlinear absorption increases whereas the threshold of OB decreases in presence of a control field. We further delineates how the control field and the decay rates modifies SA and RSA. The control of these processes find applications in optical switching, optical limiting and optical communications.

  13. MASS SPECTROMETER

    DOEpatents

    White, F.A.

    1960-08-23

    A mass spectrometer is designed with a first adjustable magnetic field for resolving an ion beam into beams of selected masses, a second adjustable magnetic field for further resolving the ion beam from the first field into beams of selected masses, a thin foil disposed in the path of the beam between the first and second magnets to dissociate molecular ions incident thereon, an electrostatic field for further resolving the ion beam from the second field into beams of selected masses, and a detector disposed adjacent to the electrostatic field to receive the ion beam.

  14. Measuring Transmission Efficiencies Of Mass Spectrometers

    NASA Technical Reports Server (NTRS)

    Srivastava, Santosh K.

    1989-01-01

    Coincidence counts yield absolute efficiencies. System measures mass-dependent transmission efficiencies of mass spectrometers, using coincidence-counting techniques reminiscent of those used for many years in calibration of detectors for subatomic particles. Coincidences between detected ions and electrons producing them counted during operation of mass spectrometer. Under certain assumptions regarding inelastic scattering of electrons, electron/ion-coincidence count is direct measure of transmission efficiency of spectrometer. When fully developed, system compact, portable, and used routinely to calibrate mass spectrometers.

  15. Study of the CH2I + O2 Reaction with a Step-Scan Fourier-Transform Infrared Absorption Spectrometer: Spectra of the Criegee Intermediate CH2OO and DIOXIRANE(?)

    NASA Astrophysics Data System (ADS)

    Huang, Yu-Hsuan; Lee, Yuan-Pern

    2014-06-01

    The Criegee intermediates are carbonyl oxides that play key roles in ozonolysis of unsaturated organic compounds. This mechanism was first proposed by Criegee in 1949, but the first direct observation of the simplest Criegee intermediate CH2OO in the gaseous phase has been reported only recently using photoionization mass spectrometry. Our group has reported the low-resolution IR spectra of CH2OO, produced from the reaction of CH2I + O2, with a second-generation step-scan Fourier-transfom IR absorption spectrometer. The spectral assignments were based on comparison of observed vibrational wavenumbers and rotational contours with theoretical predictions. Here, we report the IR absorption spectra of CH2OO at a resolution of 0.32 wn, showing partially rotationally-resolved structures. The origins of the νb{3}, νb{4}, νb{6}, and νb{8} vibrational modes of CH2OO are determined to be 1434.1, 1285.7, 909.2, and 847.3 wn, respectively. With the analysis of the vibration-rotational spectra, we provide a definitive assignment of these bands to CH2OO. The observed vibrational wavenumbers indicate a zwitterionic contribution to this singlet biradical showing a strengthened C-O bond and a weakened O-O bond. This zwitterionic character results to an extremely rapid self reaction via a cyclic dimer to form 2H2CO + O2 (1Δg). Another group of weak transient IR bands centered at 1231.5, 1213.3, and 899.8 wn are also observed. These bands might be contributed from dioxirane, which was postulated to be another important intermediate that might be isomerized from the Criegee intermediate in the reaction of O3 with 1-alkenes. O. Welz, J. D. Savee, D. L. Osborn, S. S.Vasu, C. J. Percival, D. E. Shallcross, and C. A. Taatjes, Science 335, 204 (2012). Y.-T. Su, Y.-H. Huang, H. A.Witek, and Y.-P. Lee, Science 340, 174 (2013).

  16. Dust depletion of Ca and Ti in QSO absorption-line systems

    NASA Astrophysics Data System (ADS)

    Guber, C. R.; Richter, P.

    2016-06-01

    Aims: To explore the role of titanium- and calcium-dust depletion in gas in and around galaxies, we systematically study Ti/Ca abundance ratios in intervening absorption-line systems at low and high redshift. Methods: We investigate high-resolution optical spectra obtained by the UVES instrument at the Very Large Telescope (VLT) and spectroscopically analyze 34 absorption-line systems at z ≤ 0.5 to measure column densities (or limits) for Ca ii and Ti ii. We complement our UVES data set with previously published absorption-line data on Ti/Ca for redshifts up to z ~ 3.8. Our absorber sample contains 110 absorbers including damped Lyman α systems (DLAs), sub-DLAs, and Lyman-Limit systems (LLS). We compare our Ti/Ca findings with results from the Milky Way and the Magellanic Clouds and discuss the properties of Ti/Ca absorbers in the general context of quasar absorption-line systems. Results: Our analysis indicates that there are two distinct populations of absorbers with either high or low Ti/Ca ratios with a separation at [Ti/Ca] ≈ 1. While the calcium-dust depletion in most of the absorbers appears to be severe, the titanium depletions are mild in systems with high Ti/Ca ratios. The derived trend indicates that absorbers with high Ti/Ca ratios have dust-to-gas ratios that are substantially lower than in the Milky Way. We characterize the overall nature of the absorbers by correlating Ti/Ca with other observables (e.g., metallicity, velocity-component structure) and by modeling the ionization properties of singly-ionized Ca and Ti in different environments. Conclusions: We conclude that Ca ii and Ti ii bearing absorption-line systems trace predominantly neutral gas in the disks and inner halo regions of galaxies, where the abundance of Ca and Ti reflects the local metal and dust content of the gas. Our study suggests that the Ti/Ca ratio represents a useful measure for the gas-to-dust ratio and overall metallicity in intervening absorption-line systems.

  17. Development of an airborne three-channel LED-based broadband cavity enhanced absorption spectrometer: towards an improved understanding of nighttime chemistry of NO3 and N2O5 in northwest Europe

    NASA Astrophysics Data System (ADS)

    Ouyang, Bin

    2015-04-01

    A three-channel cavity-enhanced absorption spectrometer capable of covering a broad UV-vis spectrum range has been developed in Cambridge for deployment on board the UK FAAM BAe-146 atmospheric research aircraft for measuring in situ concentrations of important atmospheric absorbers such as NO3, N2O5, NO2, IO and H2O and also aerosol extinction. So far this instrument has been deployed in two aircraft campaigns (the ROle of Nighttime chemistry in controlling the Oxidative Capacity of the atmOsphere, RONOCO, during July 2010 and January 2011; and the Coordinated Airborne Studies in the Tropics, CAST, during February 2014) with focuses on measuring NO2/NO3/N2O5 (for RONOCO) and IO (for CAST). In this talk, I will start by briefly presenting the working principle, design consideration, sensitivity test as well as intercomparison results of this novel aircraft instrument. I will then move on to present recent results from the analysis of the RONOCO campaign data, to illustrate the spatial and temporal variability of nighttime chemistry processes revealed by the high-resolution NO3 and N2O5 data collected. Significant improvements were made towards a better understanding of the oxidation of reactive VOCs by NO3 and O3 and the contribution of peroxy radicals (HO2 and RO2, of which only HO2 was successfully measured) to NO3 direct losses, and towards determining factors (organics and nitrate components of the aerosol particles, and relative humidity) that greatly influence the rate of N2O5 uptake by aerosol particles as well as directly probing the role of cloud, rain and ice scavenging in removing N2O5, in this typical northwest European environment.

  18. Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

    NASA Astrophysics Data System (ADS)

    Agrawal, Tanmay; Varun; Kumar, Anoop

    2015-10-01

    Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

  19. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) spectrometer design and performance

    NASA Technical Reports Server (NTRS)

    Macenka, Steven A.; Chrisp, Michael P.

    1987-01-01

    The development of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) has been completed at JPL. This paper outlines the functional requirements of the spectrometer optics subsystem, and describes the spectrometer optical design. The optical subsystem performance is shown in terms of spectral modulation transfer functions, radial energy distributions, and system transmission at selected wavelengths for the four spectrometers. An outline of the spectrometer alignment is included.

  20. Onsite well screening with a transportable gas chromatography/mass spectrometer system

    SciTech Connect

    Rossabi, J.; Eckenrode, B.A.; Owens, B.

    1992-10-15

    The number of hazardous waste site operations continue to multiply. The requirements for efficient chemical assessment and monitoring of these sites become more stringent daily. As more samples are required, the time required for cleanup operations also increases and may make analytical costs prohibitive. Thus improvements in operation efficiency and reduction of cost in evaluating specific sites to minimize or eliminate their toxic effects on the surrounding environment are critical. For many years a formal policy did not exist for the disposal of waste solvents and other chemicals, thus many of these compounds were disposed of ensite. So long as these materials were contained onsite they were not considered to pose a threat to the surrounding environment. We have since determined that many of these compounds found their way into the groundwater. Contaminants such as trichloroethylene and perchloroethylene, which were heavily used for cleaning and degreasing purposes, must be monitored. Groundwater wells can be used to define the location and extent of the migration of any contaminant plume and aid in the determination of required cleanup. The major problem is that monitoring of hundreds of wells may be necessary, requiring several hundred samples on a quarterly basis to characterize the degree and extent of any contamination. Onsite analysis of monitoring wells for this characterization of waste operations could provide time savings and significant cost reduction. Field analyses can provide the required analytical results quickly and at a reduced cost without compromising either sample integrity or data quality. By using onsite analytical instrumentation, such as a field-transportable gas chromatograph/mass spectrometer (GC/MS), screening analyses can be performed to eliminate retturning to the laboratory with meaningless samples. Onsite GC/MS will provide qualitative or semi-quantitative information that can significantly simplify subsequent laboratory analyses.