Sample records for vacuum ultraviolet spectroscopy

  1. Vacuum ultraviolet spectroscopy I

    CERN Document Server

    Samson, James A; Lucatorto, Thomas


    This volume is for practitioners, experimentalists, and graduate students in applied physics, particularly in the fields of atomic and molecular physics, who work with vacuum ultraviolet applications and are in need of choosing the best type of modern instrumentation. It provides first-hand knowledge of the state-of-the-art equipment sources and gives technical information on how to use it, along with a broad reference bibliography.Key Features* Aimed at experimentalists who are in need of choosing the best type of modern instrumentation in this applied field* Contains a detailed chapter on la

  2. Quantum interference spectroscopy in the vacuum ultraviolet

    NARCIS (Netherlands)

    Eikema, K. S E; Zinkstok, R. Th; Witte, S.; Hogervorst, W.; Ubachs, W.


    With two experiments on respectively krypton at 2 x 212 nm and xenon at 125 nm we have demonstrated the method of quantum interference spectroscopy in the deep- and vacuum-ultraviolet. Multiple pulses from a frequency comb laser are amplified and frequency converted and used in a Ramsey-like direct

  3. Frequency comb laser spectroscopy in the vacuum-ultraviolet region

    NARCIS (Netherlands)

    Zinkstok, R.T.; Witte, S.; Ubachs, W.M.G.; Hogervorst, W.; Eikema, K.S.E.


    We demonstrate that the output of a frequency comb laser can be amplified and upconverted to the vacuum ultraviolet (vuv) in a gaseous medium while its phase coherence is maintained to a high degree (< 1 30 of a vuv cycle). The produced vuv pulses are well suited to perform frequency comb

  4. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.


    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...

  5. Recent advances and applications of gas chromatography vacuum ultraviolet spectroscopy. (United States)

    Santos, Inês C; Schug, Kevin A


    The vacuum ultraviolet spectrophotometer was developed recently as an alternative to existing gas chromatography detectors. This detector measures the absorption of gas-phase chemical species in the range of 120-240 nm, where all chemical compounds present unique absorption spectra. Therefore, qualitative analysis can be performed and quantification follows standard Beer-Lambert law principles. Different fields of application, such as petrochemical, food, and environmental analysis have been explored. Commonly demonstrated is the capability for facile deconvolution of co-eluting analytes. The concept of additive absorption for co-eluting analytes has also been advanced for classification and speciation of complex mixtures using a data treatment procedure termed time interval deconvolution. Furthermore, pseudo-absolute quantitation can be performed for system diagnosis, as well as potentially calibrationless quantitation. In this manuscript an overview of these features, the vacuum ultraviolet spectrophotometer instrumentation, and performance capabilities are given. A discussion of the applications of the vacuum ultraviolet detector is provided by describing and discussing the papers published thus far since 2014. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Resolution of isomeric new designer stimulants using gas chromatography - Vacuum ultraviolet spectroscopy and theoretical computations. (United States)

    Skultety, Ludovit; Frycak, Petr; Qiu, Changling; Smuts, Jonathan; Shear-Laude, Lindsey; Lemr, Karel; Mao, James X; Kroll, Peter; Schug, Kevin A; Szewczak, Angelica; Vaught, Cory; Lurie, Ira; Havlicek, Vladimir


    Distinguishing isomeric representatives of "bath salts", "plant food", "spice", or "legal high" remains a challenge for analytical chemistry. In this work, we used vacuum ultraviolet spectroscopy combined with gas chromatography to address this issue on a set of forty-three designer drugs. All compounds, including many isomers, returned differentiable vacuum ultraviolet/ultraviolet spectra. The pair of 3- and 4-fluoromethcathinones (m/z 181.0903), as well as the methoxetamine/meperidine/ethylphenidate (m/z 247.1572) triad, provided very distinctive vacuum ultraviolet spectral features. On the contrary, spectra of 4-methylethcathinone, 4-ethylmethcathinone, 3,4-dimethylmethcathinone triad (m/z 191.1310) displayed much higher similarities. Their resolution was possible only if pure standards were probed. A similar situation occurred with the ethylone and butylone pair (m/z 221.1052). On the other hand, majority of forty-three drugs was successfully separated by gas chromatography. The detection limits for all the drug standards were in the 2-4 ng range (on-column amount), which is sufficient for determinations of seized drugs during forensics analysis. Further, state-of-the-art time-dependent density functional theory was evaluated for computation of theoretical absorption spectra in the 125-240 nm range as a complementary tool. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Vacuum ultraviolet spectroscopy in detached plasmas with impurity gas seeding in LHD

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, C., E-mail:; Murakami, I.; Akiyama, T.; Masuzaki, S.; Funaba, H.; Yoshinuma, M.


    We have carried out vacuum ultraviolet (VUV) spectroscopy of impurity ions in detached plasmas with impurity gas seeding in the Large Helical Device (LHD). In neon (Ne) gas seeding experiments, temporal evolutions of VUV spectral lines from Ne IV–VIII were recorded by a grazing incidence spectrometer. In addition, spatial profiles of fully ionized Ne density were measured by charge exchange spectroscopy. An electron temperature range where each ion emits is inferred based on the comparisons of the measured line intensity ratios with the calculations using collisional-radiative models.

  8. Tunable vacuum ultraviolet laser based spectrometer for angle resolved photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Rui; Mou, Daixiang; Wu, Yun; Huang, Lunan; Kaminski, Adam [Division of Materials Science and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); McMillen, Colin D.; Kolis, Joseph [Department of Chemistry, Clemson University, Clemson, South Carolina 29634 (United States); Giesber, Henry G.; Egan, John J. [Advanced Photonic Crystals LLC, Fort Mill, South Carolina 29708 (United States)


    We have developed an angle-resolved photoemission spectrometer with tunable vacuum ultraviolet laser as a photon source. The photon source is based on the fourth harmonic generation of a near IR beam from a Ti:sapphire laser pumped by a CW green laser and tunable between 5.3 eV and 7 eV. The most important part of the set-up is a compact, vacuum enclosed fourth harmonic generator based on potassium beryllium fluoroborate crystals, grown hydrothermally in the US. This source can deliver a photon flux of over 10{sup 14} photon/s. We demonstrate that this energy range is sufficient to measure the k{sub z} dispersion in an iron arsenic high temperature superconductor, which was previously only possible at synchrotron facilities.

  9. Some aspects of vacuum ultraviolet radiation physics

    CERN Document Server

    Damany, Nicole; Vodar, Boris


    Some Aspects of Vacuum Ultraviolet Radiation Physics presents some data on the state of research in vacuum ultraviolet radiation in association with areas of physics. Organized into four parts, this book begins by elucidating the optical properties of solids in the vacuum ultraviolet region (v.u.v.), particularly the specific methods of determination of optical constants in v.u.v., the properties of metals, and those of ionic insulators. Part II deals with molecular spectroscopy, with emphasis on the spectra of diatomic and simple polyatomic molecules, paraffins, and condensed phases. Part III

  10. Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water. (United States)

    Marin, Timothy W; Janik, Ireneusz; Bartels, David M; Chipman, Daniel M


    The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381 °C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as the water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. Using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching.

  11. Identification and deconvolution of carbohydrates with gas chromatography-vacuum ultraviolet spectroscopy. (United States)

    Schenk, Jamie; Nagy, Gabe; Pohl, Nicola L B; Leghissa, Allegra; Smuts, Jonathan; Schug, Kevin A


    Methodology for qualitative and quantitative determination of carbohydrates with gas chromatography coupled to vacuum ultraviolet detection (GC-VUV) is presented. Saccharides have been intently studied and are commonly analyzed by gas chromatography-mass spectrometry (GC-MS), but not always effectively. This can be attributed to their high degree of structural complexity: α/β anomers from their axial/equatorial hydroxyl group positioning at the C1-OH and flexible ring structures that lead to the open chain, five-membered ring furanose, and six-membered ring pyranose configurations. This complexity can result in convoluted chromatograms, ambiguous fragmentation patterns and, ultimately, analyte misidentification. In this study, mono-, di, and tri-saccharides were derivatized by two different methods-permethylation and oximation/pertrimethylsilylation-and analyzed by GC-VUV. These two derivatization methods were then compared for their efficiency, ease of use, and robustness. Permethylation proved to be a useful technique for the analysis of ketopentoses and pharmaceuticals soluble in dimethyl sulfoxide (DMSO), while the oximation/pertrimethylsilylation method prevailed as the more promising, overall, derivatization method. VUV spectra have been shown to be distinct and allow for efficient differentiation of isomeric species such as ketopentoses and reducing versus non-reducing sugars. In addition to identification, pharmaceutical samples containing several compounds were derivatized and analyzed for their sugar content with the GC-VUV technique to provide data for qualitative analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, J G


    The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.

  13. Vacuum ultraviolet spectroscopy and photochemistry of zinc dihydride and related molecules in low-temperature matrices. (United States)

    Henchy, Chris; Kilmartin, Una; McCaffrey, John G


    Optical absorption spectra of thin film samples, formed by the codeposition of zinc vapor with D2 and CH4, have been recorded with synchrotron radiation. With sufficiently low metal vapor flux, samples deposited at 4 K were found to consist exclusively of isolated zinc atoms for both solids. The atomic absorption bands in the quantum solids D2 and CH4 were found to exhibit large bandwidths, behavior related to the high lattice frequencies of these low mass solids. The reactivity of atomic zinc was promoted with (1)P state photolysis leading to the first recording of electronic absorption spectra for the molecules ZnD2 and CH3ZnH in the vacuum ultraviolet (VUV) region. (3)P state luminescence of atomic zinc observed in the Zn/CH4 system points to the involvement of the spin triplet state in the relaxation of CH3ZnH system as it evolves into the C3v ground state. This state is not involved in the relaxation of the higher symmetry molecule ZnD2. Time dependent density functional theory (TD-DFT) calculations were conducted to predict the electronic transitions of the inserted molecular species. Comparisons with experimental data indicate the predicted transition energies are approximately 0.5 eV less than the recorded values. Possible reasons for the discrepancy are discussed. The molecular photochemistry of ZnD2 and CH3ZnH observed in the VUV was modeled successfully with a simple four-valence electron AH2 Walsh-type diagram.

  14. Conformation of membrane-bound proteins revealed by vacuum-ultraviolet circular-dichroism and linear-dichroism spectroscopy. (United States)

    Matsuo, Koichi; Maki, Yasuyuki; Namatame, Hirofumi; Taniguchi, Masaki; Gekko, Kunihiko


    Knowledge of the conformations of a water-soluble protein bound to a membrane is important for understanding the membrane-interaction mechanisms and the membrane-mediated functions of the protein. In this study we applied vacuum-ultraviolet circular-dichroism (VUVCD) and linear-dichroism (LD) spectroscopy to analyze the conformations of α-lactalbumin (LA), thioredoxin (Trx), and β-lactoglobulin (LG) bound to phosphatidylglycerol liposomes. The VUVCD analysis coupled with a neural-network analysis showed that these three proteins have characteristic helix-rich conformations involving several helical segments, of which two amphiphilic or hydrophobic segments take part in interactions with the liposome. The LD analysis predicted the average orientations of these helix segments on the liposome: two amphiphilic helices parallel to the liposome surface for LA, two hydrophobic helices perpendicular to the liposome surface for Trx, and a hydrophobic helix perpendicular to and an amphiphilic helix parallel to the liposome surface for LG. This sequence-level information about the secondary structures and orientations was used to formulate interaction models of the three proteins at the membrane surface. This study demonstrates the validity of a combination of VUVCD and LD spectroscopy in conformational analyses of membrane-binding proteins, which are difficult targets for X-ray crystallography and nuclear magnetic resonance spectroscopy. © 2016 Wiley Periodicals, Inc.

  15. The electronic states of 1,2,3-triazole studied by vacuum ultraviolet photoabsorption and ultraviolet photoelectron spectroscopy, and a comparison with ab initio configuration interaction methods

    DEFF Research Database (Denmark)

    Palmer, Michael H.; Hoffmann, Søren Vrønning; Jones, Nykola C.


    The Rydberg states in the vacuum ultraviolet photoabsorption spectrum of 1,2,3-triazole have been measured and analyzed with the aid of comparison to the UV valence photoelectron ionizations and the results of ab initio configuration interaction (CI) calculations. Calculated electronic ionization...

  16. Vacuum Ultraviolet Photoionization of Complex Chemical Systems. (United States)

    Kostko, Oleg; Bandyopadhyay, Biswajit; Ahmed, Musahid


    Tunable vacuum ultraviolet (VUV) radiation coupled to mass spectrometry is applied to the study of complex chemical systems. The identification of novel reactive intermediates and radicals is revealed in flame, pulsed photolysis, and pyrolysis reactors, leading to the elucidation of spectroscopy, reaction mechanisms, and kinetics. Mass-resolved threshold photoelectron photoion coincidence measurements provide unprecedented access to vibrationally resolved spectra of free radicals present in high-temperature reactors. Photoionization measurements in water clusters, nucleic acid base dimers, and their complexes with water provide signatures of proton transfer in hydrogen-bonded and π-stacked systems. Experimental and theoretical methods to track ion-molecule reactions and fragmentation pathways in intermolecular and intramolecular hydrogen-bonded systems in sugars and alcohols are described. Photoionization of laser-ablated molecules, clusters, and their reaction products inform thermodynamics and spectroscopy that are relevant to astrochemistry and catalysis. New directions in coupling VUV radiation to interrogate complex chemical systems are discussed.

  17. Vacuum-Ultraviolet Photovoltaic Detector. (United States)

    Zheng, Wei; Lin, Richeng; Ran, Junxue; Zhang, Zhaojun; Ji, Xu; Huang, Feng


    Over the past two decades, solar- and astrophysicists and material scientists have been researching and developing new-generation semiconductor-based vacuum ultraviolet (VUV) detectors with low power consumption and small size for replacing traditional heavy and high-energy-consuming microchannel-detection systems, to study the formation and evolution of stars. However, the most desirable semiconductor-based VUV photovoltaic detector capable of achieving zero power consumption has not yet been achieved. With high-crystallinity multistep epitaxial grown AlN as a VUV-absorbing layer for photogenerated carriers and p-type graphene (with unexpected VUV transmittance >96%) as a transparent electrode to collect excited holes, we constructed a heterojunction device with photovoltaic detection for VUV light. The device exhibits an encouraging VUV photoresponse, high external quantum efficiency (EQE) and extremely fast tempera response (80 ns, 10 4 -10 6 times faster than that of the currently reported VUV photoconductive devices). This work has provided an idea for developing zero power consumption and integrated VUV photovoltaic detectors with ultrafast and high-sensitivity VUV detection capability, which not only allows future spacecraft to operate with longer service time and lower launching cost but also ensures an ultrafast evolution of interstellar objects.

  18. Time-resolved photoelectron spectroscopy of polyatomic molecules using 42-nm vacuum ultraviolet laser based on high harmonics generation (United States)

    Nishitani, Junichi; West, Christopher W.; Higashimura, Chika; Suzuki, Toshinori


    Time-resolved photoelectron spectroscopy (TRPES) of gaseous polyatomic molecules using 266-nm (4.7 eV) pump and 42-nm (29.5 eV) probe pulses is presented. A 1-kHz Ti:sapphire laser with a 35 fs pulse duration is employed to generate high harmonics in Kr gas, and the 19th harmonic (42-nm) was selected using two SiC/Mg mirrors. Clear observation of the ultrafast electronic dephasing in pyrazine and photoisomerization of 1,3-cyclohexadiene demonstrates the feasibility of TRPES with the UV pump and VUV probe pulses under weak excitation conditions in the perturbation regime.

  19. Large-Area Vacuum Ultraviolet Sensors (United States)

    Aslam, Shahid; Franz, David


    Pt/(n-doped GaN) Schottky-barrier diodes having active areas as large as 1 cm square have been designed and fabricated as prototypes of photodetectors for the vacuum ultraviolet portion (wavelengths approximately equal 200 nm) of the solar spectrum. In addition to having adequate sensitivity to photons in this wavelength range, these photodetectors are required to be insensitive to visible and infrared components of sunlight and to have relatively low levels of dark current.

  20. The electronic states of 1,2,4-triazoles: A study of 1H- and1-methyl-1,2,4-triazole by vacuum ultraviolet photoabsorption and ultraviolet photoelectron spectroscopy and a comparison with ab initio configuration interaction computations

    DEFF Research Database (Denmark)

    Palmer, Michael H.; Camp, Philip J.; Hoffmann, Søren Vrønning


    The first vacuum ultraviolet absorption spectrum of a 1,2,4-triazole has been obtained and analyzed in detail, with assistance from both an enhanced UV photoelectron spectroscopic study and ab initio multi-reference multi-root configuration interaction procedures. For both 1H- and 1-methyl-1,2,4-...

  1. Electronic excitation of furfural as probed by high-resolution vacuum ultraviolet spectroscopy, electron energy loss spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira da Silva, F.; Lange, E. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Limão-Vieira, P., E-mail:, E-mail:, E-mail: [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Jones, N. C.; Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Institut de Chimie-Bât. B6C, Université de Liège, B-4000 Liège 1 (Belgium); Brunger, M. J., E-mail:, E-mail:, E-mail: [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); and others


    The electronic spectroscopy of isolated furfural (2-furaldehyde) in the gas phase has been investigated using high-resolution photoabsorption spectroscopy in the 3.5–10.8 eV energy-range, with absolute cross section measurements derived. Electron energy loss spectra are also measured over a range of kinematical conditions. Those energy loss spectra are used to derive differential cross sections and in turn generalised oscillator strengths. These experiments are supported by ab initio calculations in order to assign the excited states of the neutral molecule. The good agreement between the theoretical results and the measurements allows us to provide the first quantitative assignment of the electronic state spectroscopy of furfural over an extended energy range.

  2. Absorption spectroscopy of xenon and ethylene-noble gas mixtures at high pressure: Towards Bose-Einstein condensation of vacuum ultraviolet photons

    CERN Document Server

    Wahl, Christian; Schmitt, Julian; Vewinger, Frank; Christopoulos, Stavros; Weitz, Martin


    Bose-Einstein condensation is a phenomenon well known for material particles as cold atomic gases, and this concept has in recent years been extended to photons confined in microscopic optical cavities. Essential for the operation of such a photon condensate is a thermalization mechanism that conserves the average particle number, as in the visible spectral regime can be realized by subsequent absorption re-emission processes in dye molecules. Here we report on the status of an experimental effort aiming at the extension of the concept of Bose-Einstein condensation of photons towards the vacuum ultraviolet spectral regime, with gases at high pressure conditions serving as a thermalization medium for the photon gas. We have recorded absorption spectra of xenon gas at up to 30 bar gas pressure of the $5p^6 - 5p^56s$ transition with a wavelength close to 147 nm. Moreover, spectra of ethylene noble gas mixtures between 155 and 180 nm wavelength are reported.

  3. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source. (United States)

    Roberts, F Sloan; Anderson, Scott L


    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  4. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    Energy Technology Data Exchange (ETDEWEB)

    Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)


    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry.

  5. Vacuum ultraviolet detector for gas chromatography. (United States)

    Schug, Kevin A; Sawicki, Ian; Carlton, Doug D; Fan, Hui; McNair, Harold M; Nimmo, John P; Kroll, Peter; Smuts, Jonathan; Walsh, Phillip; Harrison, Dale


    Analytical performance characteristics of a new vacuum ultraviolet (VUV) detector for gas chromatography (GC) are reported. GC-VUV was applied to hydrocarbons, fixed gases, polyaromatic hydrocarbons, fatty acids, pesticides, drugs, and estrogens. Applications were chosen to feature the sensitivity and universal detection capabilities of the VUV detector, especially for cases where mass spectrometry performance has been limited. Virtually all chemical species absorb and have unique gas phase absorption cross sections in the approximately 120-240 nm wavelength range monitored. Spectra are presented, along with the ability to use software for deconvolution of overlapping signals. Some comparisons with experimental synchrotron data and computed theoretical spectra show good agreement, although more work is needed on appropriate computational methods to match the simultaneous broadband electronic and vibronic excitation initiated by the deuterium lamp. Quantitative analysis is governed by Beer-Lambert Law relationships. Mass on-column detection limits reported for representatives of different classes of analytes ranged from 15 (benzene) to 246 pg (water). Linear range measured at peak absorption for benzene was 3-4 orders of magnitude. Importantly, where absorption cross sections are known for analytes, the VUV detector is capable of absolute determination (without calibration) of the number of molecules present in the flow cell in the absence of chemical interferences. This study sets the stage for application of GC-VUV technology across a wide breadth of research areas.

  6. Vacuum Ultraviolet Laser Probe of Chemical Dynamics of Aerospace Relevance (United States)


    RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) 09/12/12 01/15/09-11/30/11 VACUUM ULTRAVIOLET LASER PROBES OF CHEMICAL DYNAMICS to be limited. Standard Form 298 Back (Rev. 8/98) FINAL AFOSR REPORT (Dec. 1, 2008-Nov. 30, 2011) I. Grant Title: Vacuum Ultraviolet ...goal of this research program is to provide pertinent information about the energetics, photochemistry , and chemical dynamics of spacecraft effluents

  7. Atomic Oscillator Strengths In The Vacuum Ultraviolet (United States)

    Nave, Gillian; Sansonetti, C. J.; Szabo, C. I.


    Transitionsin singly-ionized and doubly-ionized iron-group elements give rise to prominent emission lines from a wide variety of astrophysical objects. Although the database of experimental oscillator strengths of Fe II has also been greatly extended by the FERRUM project, few experimental oscillator strengths are available in the region below 1600 Å, where many levels that give rise to emission lines at longer wavelengths have their dominant decays. The established way to measure accurate oscillator strengths for atomic lines combines the measurement of a lifetime of an upper energy level with a separate measurement of the branching fractions of all the lines emitted from that level. This technique relies on being able to observe all the spectral lines emitted by the upper level, which range down to Ly-α or below for many fluorescence lines. We have developed techniques to measure branching fractions in the vacuum ultraviolet using our 10.7-m normal incidence grating spectrograph. For this we use phosphor image plates as replacements for the photographic plates previously used on this instrument. Image plates are sensitive to wavelengths from the X-ray region to 2200 Å, and have a linear intensity response with a dynamic range of at least 10000. We have recorded spectra of iron-neon hollow cathode and Penning discharges, using a deuterium standard lamp for radiometric calibration. We will present the first measurements of oscillator strengths using this technique. We are also investigating methods of radiometric calibration below 1150 Å using hollow cathode standard lamps. This will enable us to measure branching ratios down to 800 Å or below. This work is partially funded by NASA under the inter-agency agreement W-10,255.

  8. Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV

    Energy Technology Data Exchange (ETDEWEB)

    Limão-Vieira, P., E-mail: [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferreira da Silva, F.; Almeida, D. [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Hoshino, M.; Tanaka, H. [Department of Physics, Sophia University, Tokyo 102-8554 (Japan); Mogi, D. [Development and Marketing Department, New Products Development Division, Kanto Denka, Kogyo Co., Ltd., Chiyoda-ku, Tokyo 101-0063 (Japan); Tanioka, T. [Shibukawa Development Research Laboratory, New Products Development Division, Kanto Denka Kogyo Co., Ltd., Shibukawa City, Gunma 377-8513 (Japan); Mason, N. J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hoffmann, S. V. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Århus C (Denmark); Hubin-Franskin, M.-J.; Delwiche, J. [Départment de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, allée de la Chimie 3, B-4000 Liège 1 (Belgium)


    The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0–10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) ({sup 1}Δ←{sup 1}Σ{sup +}) transition, with a new weak transition assigned to ({sup 1}Σ{sup −}←{sup 1}Σ{sup +}) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to {sup 1}Σ{sup +} and {sup 1}Π transitions. Based on our recent measurements of differential cross sections for the optically allowed ({sup 1}Σ{sup +} and {sup 1}Π) transitions of COS by electron impact, the optical oscillator strength f{sub 0} value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20–50 km)

  9. Ultraviolet, Visible, and Fluorescence Spectroscopy (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  10. Generation of a vacuum ultraviolet to visible Raman frequency comb in H2-filled kagomé photonic crystal fiber. (United States)

    Mridha, M K; Novoa, D; Bauerschmidt, S T; Abdolvand, A; St J Russell, P


    We report on the generation of a purely vibrational Raman comb, extending from the vacuum ultraviolet (184 nm) to the visible (478 nm), in hydrogen-filled kagomé-style photonic crystal fiber pumped at 266 nm. Stimulated Raman scattering and molecular modulation processes are enhanced by higher Raman gain in the ultraviolet. Owing to the pressure-tunable normal dispersion landscape of the "fiber + gas" system in the ultraviolet, higher-order anti-Stokes bands are generated preferentially in higher-order fiber modes. The results pave the way toward tunable fiber-based sources of deep and vacuum ultraviolet light for applications in, e.g., spectroscopy and biomedicine.

  11. Vacuum ultraviolet radiometry of xenon positive column discharges (United States)

    Doughty, D. A.; Fobare, D. F.


    In order to judge the potential fluorescent lamp applications of various low-pressure positive column discharges it is necessary to measure the absolute power emitted in the ultraviolet region of the spectrum. For rare-gas discharges the principle emission occurs in the vacuum ultraviolet so that it is difficult to measure the radiant emittance (power per unit area) of the resonance radiation by standard methods. Two independent techniques are discussed for measuring the radiant emittance of positive column discharges in the vacuum ultraviolet. These techniques are used to study xenon positive column discharges at the resonance wavelength of 147 nm. The first method relies on the measurement of the resonance level density by absorption techniques. The effective decay rate of the resonance level is then determined by the simulation of resonance radiation transport. These two quantities are combined to yield the radiant emittance at 147 nm without implementing vacuum ultraviolet techniques. The second method uses a measurement of the resonance radiation normal to the positive column axis made with a calibrated vacuum ultraviolet detector. The angular distribution of the resonance radiation leaving the tube is determined by the simulation of resonance radiation transport. The detector measurement places the angular distribution of the radiance on an absolute scale, which can then be integrated to yield the radiant emittance. These two techniques are compared for pure xenon discharges at various pressures and currents.

  12. Metallic Na formation in NaCl crystals with irradiation of electron or vacuum ultraviolet photon

    Energy Technology Data Exchange (ETDEWEB)

    Owaki, Shigehiro [Osaka Prefecture Univ., Sakai, Osaka (Japan). Coll. of Integrated Arts and Sciences; Koyama, Shigeko; Takahashi, Masao; Kamada, Masao; Suzuki, Ryouichi


    Metallic Na was formed in NaCl single crystals with irradiation of a variety of radiation sources and analyzed the physical states with several methods. In the case of irradiation of 21 MeV electron pulses to the crystal blocks, the optical absorption and lifetime measurement of positron annihilation indicated appearance of Na clusters inside. Radiation effects of electron beam of 30 keV to the crystals in vacuum showed the appearance of not only metallic Na but atomic one during irradiation with Auger electron spectroscopy. Intense photon fluxes in vacuum ultraviolet region of synchrotron radiation were used as another source and an analyzing method of ultraviolet photoelectron spectroscopy. The results showed the metallic Na layered so thick that bulk plasmon can exist. (author)

  13. Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, B. [Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad 380009 (India); Nair, B. G.; Mason, N. J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lo, J.-I.; Cheng, B.-M. [National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Kundu, S.; Davis, D.; Prabhudesai, V.; Krishnakumar, E. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Raja Sekhar, B. N., E-mail: [B-4, Indus-1, BARC Spectroscopy Lab at Indus-1, Atomic and Molecular Physics Division, BARC, Mumbai and RRCAT, Indore 452013 (India)


    Following the recent report of the first identification of methyl acetate (CH{sub 3}COOCH{sub 3}) in the interstellar medium (ISM), we have carried out vacuum ultraviolet (VUV) and infrared (IR) spectroscopy studies on methyl acetate from 10 K until sublimation in an ultrahigh vacuum chamber simulating astrochemical conditions. We present the first VUV and IR spectra of methyl acetate relevant to ISM conditions. Spectral signatures clearly showed molecular reorientation to have started in the ice by annealing the amorphous ice formed at 10 K. An irreversible phase change from amorphous to crystalline methyl acetate ice was found to occur between 110 K and 120 K.

  14. Large area, surface discharge pumped, vacuum ultraviolet light source (United States)

    Sze, Robert C.; Quigley, Gerard P.


    Large area, surface discharge pumped, vacuum ultraviolet (VUV) light source. A contamination-free VUV light source having a 225 cm.sup.2 emission area in the 240-340 nm region of the electromagnetic spectrum with an average output power in this band of about 2 J/cm.sup.2 at a wall-plug efficiency of approximately 5% is described. Only ceramics and metal parts are employed in this surface discharge source. Because of the contamination-free, high photon energy and flux, and short pulse characteristics of the source, it is suitable for semiconductor and flat panel display material processing.

  15. Vacuum ultraviolet electronic properties of liquids. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Painter, L.R.


    A program to study the electronic structure of liquids over the energy range from 2 to 25 eV was carried out from November, 1968 to October 1980. These studies basically consisted of measuring the reflectance, transmittance, photoionization, and photoemission of liquids in the vacuum ultraviolet spectral region as a function of angle of incidence and photon energy. Such measurements are analyzed to yield the optical and dielectric functions of the liquid as functions of photon energy. A summary of the progress in the program is presented. (GHT)

  16. CIV Polarization Measurements Using a Vacuum Ultraviolet Fabry Perot (United States)

    West, Edward A.


    Marshall Space Flight Center's (MSFC) is developing a Vacuum Ultraviolet (VUV) Fabry Perot that will be launched on a sounding rocket for high throughput, high-cadence, extended field of view CIV (155nm) measurements. These measurements will provide (i) Dopplergrams for studies of waves, oscillations, explosive events, and mass motions through the transition region, and, (ii), polarization measurements to study the magnetic field in the transition region. This paper will describe the scientific goals of the instrument, a brief description of the optics and the polarization characteristics of the VUV Fabry Perot.

  17. Absolute photon-flux measurements in the vacuum ultraviolet (United States)

    Samson, J. A. R.; Haddad, G. N.


    Absolute photon-flux measurements in the vacuum ultraviolet have extended to short wavelengths by use of rare-gas ionization chambers. The technique involves the measurement of the ion current as a function of the gas pressure in the ion chamber. The true value of the ion current, and hence the absolute photon flux, is obtained by extrapolating the ion current to zero gas pressure. Examples are given at 162 and 266 A. The short-wavelength limit is determined only by the sensitivity of the current-measuring apparatus and by present knowledge of the photoionization processes that occur in the rate gases.

  18. Ultraviolet Spectroscopy of Asteroid(4) Vesta (United States)

    Li, Jian-Yang; Bodewits, Dennis; Feaga, Lori M.; Landsman, Wayne; A'Hearn, Michael F.; Mutchler, Max J.; Russell, Christopher T.; McFadden, Lucy A.; Raymond, Carol A.


    We report a comprehensive review of the UV-visible spectrum and rotational lightcurve of Vesta combining new observations by Hubble Space Telescope and Swift with archival International Ultraviolet Explorer observations. The geometric albedos of Vesta from 220 nm to 953 nm arc derived by carefully comparing these observations from various instruments at different times and observing geometries. Vesta has a rotationally averaged geometric albedo of 0.09 at 250 nm, 0.14 at 300 nm, 0.26 at 373 nm, 0.38 at 673 nm, and 0.30 at 950 nm. The linear spectral slope in the ultraviolet displays a sharp minimum ncar sub-Earth longitude of 20deg, and maximum in the eastern hemisphere. This is completely consistent with the distribution of the spectral slope in the visible wavelength. The uncertainty of the measurement in the ultraviolet is approx.20%, and in the visible wavelengths better than 10%. The amplitude of Vesta's rotational lightcurves is approx.10% throughout the range of wavelengths we observed, but is smaller at 950 nm (approx.6%) ncar the 1-micron mafic band center. Contrary to earlier reports, we found no evidence for any difference between the phasing of the ultraviolet and visible/ncar-infrared lightcurves with respect to sub-Earth longitude. Vesta's average spectrum between 220 and 950 nm can well be described by measured reflectance spectra of fine particle howardite-like materials of basaltic achondrite meteorites. Combining this with the in-phase behavior of the ultraviolet, visible. and ncar-infrared lightcurves, and the spectral slopes with respect to the rotational phase, we conclude that there is no global ultraviolet/visible reversal on Vesta. Consequently, this implies lack of global space weathering on Vesta. Keyword,: Asteroid Vesta; Spectrophotometry; Spectroscopy; Ultraviolet observations; Hubble Space Telescope observations

  19. Nonthermal combined ultraviolet and vacuum-ultraviolet curing process for organosilicate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, H.; Guo, X.; Pei, D.; Li, W.; Blatz, J.; Hsu, K.; Benjamin, D.; Shohet, J. L., E-mail: [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Lin, Y.-H.; Fung, H.-S.; Chen, C.-C. [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Nishi, Y. [Stanford University, Stanford, California 94305 (United States)


    Porous SiCOH films are of great interest in semiconductor fabrication due to their low-dielectric constant properties. Post-deposition treatments using ultraviolet (UV) light on organosilicate thin films are required to decompose labile pore generators (porogens) and to ensure optimum network formation to improve the electrical and mechanical properties of low-k dielectrics. The goal of this work is to choose the best vacuum-ultraviolet photon energy in conjunction with vacuum ultraviolet (VUV) photons without the need for heating the dielectric to identify those wavelengths that will have the most beneficial effect on improving the dielectric properties and minimizing damage. VUV irradiation between 8.3 and 8.9 eV was found to increase the hardness and elastic modulus of low-k dielectrics at room temperature. Combined with UV exposures of 6.2 eV, it was found that this “UV/VUV curing” process is improved compared with current UV curing. We show that UV/VUV curing can overcome drawbacks of UV curing and improve the properties of dielectrics more efficiently without the need for high-temperature heating of the dielectric.

  20. Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations

    Energy Technology Data Exchange (ETDEWEB)

    Śmiałek, M. A., E-mail: [Department of Control and Energy Engineering, Faculty of Ocean Engineering and Ship Technology, Gdańsk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdańsk (Poland); Łabuda, M.; Guthmuller, J. [Department of Theoretical Physic and Quantum Information, Faculty of Applied Physics and Mathematics, Gdańsk University of Technology, Gabriela Narutowicza 11/12, 80-233 Gdańsk (Poland); Hubin-Franskin, M.-J.; Delwiche, J. [Département de Chimie, Université de Liège, Institut de Chimie-Bât. B6C, B-4000 Liège (Belgium); Duflot, D. [Laboratoire de Physique des Lasers, Atomes et Molécules (PhLAM), UMR CNRS 8523, Université Lille1 Sciences et Technologies, F-59655 Villeneuve d' Ascq Cedex (France); Mason, N. J. [Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hoffmann, S. V.; Jones, N. C. [ISA, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, Building 1520, DK-8000 Aarhus C (Denmark); Limão-Vieira, P., E-mail: [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)


    The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C{sub 2}H{sub 5}OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20–50 km)

  1. The extra-terrestrial vacuum-ultraviolet wavelength range (United States)

    Timothy, J. Gethyn; Wilhelm, Klaus; Xia, Lidong

    Electromagnetic radiation in the vacuum-ultraviolet (VUV) and extra-terrestrial range at wavelengths from 10 nm to 300 nm is absorbed in the upper atmosphere by ozone, molecular and atomic oxygen, and molecular nitrogen. Observations at wavelengths down to ≈ 200 nm can be carried out from stratospheric balloons, and observations below 200 nm require space platforms operating at altitudes above 250 km. The VUV spectral region contains emission lines and continua arising from plasma at formation temperatures ranging from about 104 K to more than 107 K. This chapter describes the wide range of plasma diagnostic techniques available at VUV wavelengths, and the development of instrumentation for studies of the high-temperature solar outer atmosphere and astrophysical plasmas. Finally, the prospects for future studies are briefly discussed.

  2. 3m vacuum ultraviolet spectrometer with optical multichanel detector

    Energy Technology Data Exchange (ETDEWEB)

    Marin, P.; Peraza, C. [Instituto Investigacion Basica. CIEMAT (Spain); Blanco, F.; Campos, J. [Universidad Complutense de Madrid (Spain). Facultad de Ciencias Fisicas


    This paper, describes the design and the performance of a normal incidence vacuum ultraviolet spectrometer, for the 300-2400 A spectral range. It is provided with a multichannel detection system. The monochromator is original design and it has been built at CIEMAT: It is equipped with a 3 m concave holographic grating with 2400 grooves/mm. The multichannel detector consists of a windowless double microchannel plate/phosphor screen image intensifier, coupled by fiber optic to a 1024 elements self-scanning linear photodiode array. The output from the arrays is digitized by a 12-bit analog to digital converter and stored in a computer for its later analysis. The necessary software to store and display data has been developed. (Author)

  3. 3m vacuum ultraviolet spectrometer with optical multichanel detector

    Energy Technology Data Exchange (ETDEWEB)

    Marin, P.; Peraza, C. (Instituto Investigacion Basica. CIEMAT (Spain)); Blanco, F.; Campos, J. (Universidad Complutense de Madrid (Spain). Facultad de Ciencias Fisicas)


    This paper, describes the design and the performance of a normal incidence vacuum ultraviolet spectrometer, for the 300-2400 A spectral range. It is provided with a multichannel detection system. The monochromator is original design and it has been built at CIEMAT: It is equipped with a 3 m concave holographic grating with 2400 grooves/mm. The multichannel detector consists of a windowless double microchannel plate/phosphor screen image intensifier, coupled by fiber optic to a 1024 elements self-scanning linear photodiode array. The output from the arrays is digitized by a 12-bit analog to digital converter and stored in a computer for its later analysis. The necessary software to store and display data has been developed. (Author)

  4. Far Ultraviolet Spectroscopy of Saturn's Icy Moon Rhea (United States)

    Elowitz, Mark; Hendrix, Amanda; Mason, Nigel J.; Sivaraman, Bhalamurugan


    We present an analysis of spatially resolved, far-UV reflectance spectra of Saturn’s icy satellite Rhea, collected by the Cassini Ultraviolet Imaging Spectrograph (UVIS). In recent years ultraviolet spectroscopy has become an important tool for analysing the icy satellites of the outer solar system (1Hendrix & Hansen, 2008). Far-UV spectroscopy provides unique information about the molecular structure and electronic transitions of chemical species. Many molecules that are suspected to be present in the icy surfaces of moons in the outer solar system have broad absorption features due to electronic transitions that occur in the far-UV portion of the spectrum. The studies show that Rhea, like the other icy satellites of the Saturnian system are dominated by water-ice as evident by the 165-nm absorption edge, with minor UV absorbing contaminants. Far-UV spectra of several Saturnian icy satellites, including Rhea and Dione, show an unexplained weak absorption feature centered near 184 nm. To carry out the geochemical survey of Rhea’s surface, the UVIS observations are compared with vacuum-UV spectra of thin-ice samples measured in laboratory experiments. Thin film laboratory spectra of water-ice and other molecular compounds in the solid phase were collected at near-vacuum conditions and temperatures identical to those at the surface of Rhea. Comparison between the observed far-UV spectra of Rhea’s surface ice and modelled spectra based on laboratory absorption measurements of different non-water-ice compounds show that two possible chemical compounds could explain the 184-nm absorption feature. The two molecular compounds include simple chlorine molecules and hydrazine monohydrate. Attempts to explain the source(s) of these compounds on Rhea and the scientific implications of their possible discovery will be summarized.[1] Hendrix, A. R. & Hansen, C. J. (2008). Icarus, 193, pp. 323-333.

  5. Photodegradation of perfluorooctanoic acid by 185 nm vacuum ultraviolet light. (United States)

    Chen, Jing; Zhang, Peng-yi; Liu, Jian


    The photodegradation of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water by 185 nm vacuum ultraviolet (VUV) light was examined to develop an effective technology to deal with PFOA pollution. PFOA degraded very slowly under irradiation of 254 nm UV light. However, 61.7% of initial PFOA was degraded by 185 nm VUV light within 2 h, and defluorination ratio reached 17.1%. Pseudo first-order-kinetics well simulated its degradation and defluorination. Besides, fluoride ion formed in water, 4 shorter-chain perfluorinated carboxylic acids (PFCAs), that is, perfluoroheptanoic acid, perfluorohexanoic acid, perfluoropentanoic acid, and perfluorobutanoic acid. These were identified as intermediates by LC-MS measurement. These PFCAs consecutively formed and further degraded with irradiation time. According to the mass balance calculation, no other byproducts were formed. It was proposed that PFCAs initially are decarboxylated by 185 nm light, and the radical thus formed reacts with water to form shorter-chain PFCA with one less CF2 unit.

  6. Interfacial chemistry of poly(methyl methacrylate) arising from exposure to vacuum-ultraviolet light and atomic oxygen. (United States)

    Yuan, Hanqiu; Killelea, Daniel R; Tepavcevic, Sanja; Kelber, Scott I; Sibener, S J


    We herein report on the chemical and physical changes that occur in thin films of poly(methyl methacrylate), PMMA, induced by exposure to high-energy vacuum ultraviolet radiation and a supersonic beam of neutral, ground electronic state O((3)P) atomic oxygen. A combination of in situ quartz crystal microbalance and in situ Fourier-transform infrared reflection-absorption spectroscopy were used to determine the photochemical reaction kinetics and mechanisms during irradiation. The surface morphological changes were measured with atomic force microscopy. The results showed there was no enhancement in the mass loss rate during simultaneous exposure of vacuum ultraviolet (VUV) radiation and atomic oxygen. Rather, the rate of mass loss was impeded when the polymer film was exposed to both reagents. This study elucidates the kinetics of photochemical and oxidative reaction for PMMA, and shows that the synergistic effect involving VUV irradiation and exposure to ground state atomic oxygen depends substantially on the relative fluxes of these reagents.

  7. Solar CIV Vacuum-Ultraviolet Fabry-Perot Interferometers (United States)

    Gary, G. Allen; West, Edward A.; Rees, David; McKay, Jack A.; Zukic, Maumer; Herman, Peter


    Aims: A tunable, high spectral resolution, high effective finesse, vacuum ultraviolet (VUV) Fabry-Perot interferometer (PPI) is designed for obtaining narrow-passband images, magnetograms, and Dopplergrams of the transition region emission line of CIV (155 nm). Methods: The integral part of the CIV narrow passband filter package (with a 2-10 pm FWHM) consists of a multiple etalon system composed of a tunable interferometer that provides high-spectral resolution and a static low-spectral resolution interferometer that allows a large effective free spectral range. The prefilter for the interferometers is provided by a set of four mirrors with dielectric high-reflective coatings. A tunable interferometer, a VUV piezoelectric-control etalon, has undergone testing using the surrogate F2 eximer laser line at 157 nm for the CIV line. We present the results of the tests with a description of the overall concept for a complete narrow-band CIV spectral filter. The static interferometer of the filter is envisioned as being hudt using a set of fixed MgF2 plates. The four-mirror prefilter is designed to have dielectric multilayer n-stacks employing the design concept used in the Ultraviolet Imager of NASA's Polar Spacecraft. A dual etalon system allows the effective free spectral range to be commensurate with the prefilter profile. With an additional etalon, a triple etalon system would allow a spectrographic resolution of 2 pm. The basic strategy has been to combine the expertise of spaceflight etalon manufacturing with VUV coating technology to build a VUV FPI which combines the best attributes of imagers and spectrographs into a single compact instrument. Results. Spectro-polarimetry observations of the transition region CIV emission can be performed to increase the understanding of the magnetic forces, mass motion, evolution, and energy release within the solar atmosphere at the base of the corona where most of the magnetic field is approximately force-free. The 2D imaging

  8. Selective adsorption of protein on micropatterned flexible poly(ethylene terephthalate) surfaces modified by vacuum ultraviolet lithography

    Energy Technology Data Exchange (ETDEWEB)

    Li Shaoying [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Rd, Wuhan 430070 (China); Wu Zhongkui, E-mail: [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Rd, Wuhan 430070 (China); Tang Hongxiao; Yang Jun [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Rd, Wuhan 430070 (China)


    Protein micropattern was fabricated on the flexible poly(ethylene terephthalate) (PET) surfaces modified by vacuum ultraviolet lithography (VUV). Chemical composition and topographies changes of the modified PET surfaces were characterized and analyzed by X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and static water contact angle. As demonstrated in fluorescence microscope, the protein patterns were surrounded by a protein-repellant layer of poly(ethylene glycol) (PEG) that were faithful reproductions of the copper mesh. These results suggested that this technique can be extended to other polymeric materials and will be useful in fields where arrays of protein patterns are desired.

  9. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. I. Argon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Boffard, John B., E-mail:; Lin, Chun C. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Culver, Cody [Materials Science Program, University of Wisconsin, Madison, WI 53706 (United States); Wang, Shicong; Wendt, Amy E. [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, WI 53706 (United States); Radovanov, Svetlana; Persing, Harold [Varian Semiconductor Equipment, Applied Materials Inc., Gloucester, MA 01939 (United States)


    Vacuum ultraviolet (VUV) photons emitted from excited atomic states are ubiquitous in material processing plasmas. The highly energetic photons can induce surface damage by driving surface reactions, disordering surface regions, and affecting bonds in the bulk material. In argon plasmas, the VUV emissions are due to the decay of the 1s{sub 4} and 1s{sub 2} principal resonance levels with emission wavelengths of 104.8 and 106.7 nm, respectively. The authors have measured the number densities of atoms in the two resonance levels using both white light optical absorption spectroscopy and radiation-trapping induced changes in the 3p{sup 5}4p→3p{sup 5}4s branching fractions measured via visible/near-infrared optical emission spectroscopy in an argon inductively coupled plasma as a function of both pressure and power. An emission model that takes into account radiation trapping was used to calculate the VUV emission rate. The model results were compared to experimental measurements made with a National Institute of Standards and Technology-calibrated VUV photodiode. The photodiode and model results are in generally good accord and reveal a strong dependence on the neutral gas temperature.

  10. Comparing vacuum and extreme ultraviolet radiation for postionization of laser desorbed neutrals from bacterial biofilms and organic fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Gasper, Gerald L. [Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street (m/c 111), Chicago, IL 60607 (United States); Takahashi, Lynelle K. [Department of Chemistry, University of California, Berkeley, Room 419 Latimer Hall, Berkeley, CA 94720-1460 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Zhou Jia; Ahmed, Musahid [Chemical Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Moore, Jerry F. [MassThink LLC, 500 East Ogden Avenue Suite 200, Naperville, IL 60563 (United States); Hanley, Luke, E-mail: [Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor Street (m/c 111), Chicago, IL 60607 (United States)


    Vacuum and extreme ultraviolet radiation from 8 to 24 eV generated at a synchrotron was used to postionize laser desorbed neutrals of antibiotic-treated biofilms and a modified fullerene using laser desorption postionization mass spectrometry (LDPI-MS). Results show detection of the parent ion, various fragments, and extracellular material from biofilms using LDPI-MS with both vacuum and extreme ultraviolet photons. Parent ions were observed for both cases, but extreme ultraviolet photons (16-24 eV) induced more fragmentation than vacuum ultraviolet (8-14 eV) photons.

  11. Comparing Vacuum and Extreme Ultraviolet Radiation for Postionization of Laser Desorbed Neutrals from Bacterial Biofilms and Organic Fullerene

    Energy Technology Data Exchange (ETDEWEB)

    Gaspera, Gerald L.; Takahashi, Lynelle K.; Zhou, Jia; Ahmed, Musahid; Moored, Jerry F.; Hanley, Luke


    Vacuum and extreme ultraviolet radiation from 8 - 24 eV generated at a synchrotron was used to postionize laser desorbed neutrals of antibiotic-treated biofilms and a modified fullerene using laser desorption postionization mass spectrometry (LDPI-MS). Results show detection of the parent ion, various fragments, and extracellular material from biofilms using LDPI-MS with both vacuum and extreme ultraviolet photons. Parent ions were observed for both cases, but extreme ultraviolet photons (16-24 eV) induced more fragmentation than vacuum ultraviolet (8-14 eV) photons.

  12. Synchrotron vacuum ultraviolet radiation studies of the D 1Πu state of H2

    NARCIS (Netherlands)

    Dickenson, G. D.; Ivanov, T. I.; Roudjane, M.; de Oliveira, N.; Joyeux, D.; Nahon, L.; Tchang-Brillet, W. Ü L; Glass-Maujean, M.; Haas, I.; Ehresmann, A.; Ubachs, W.


    The 3pπD 1Πu state of the H2 molecule was reinvestigated with different techniques at two synchrotron installations. The Fourier transform spectrometer in the vacuum ultraviolet wavelength range of the DESIRS beamline at the SOLEIL synchrotron was used for recording absorption spectra of the D Π1u

  13. Photoluminescence excitation spectra of lanthanide doped YAlO3 in vacuum ultraviolet region (United States)

    Shimizu, Yuhei; Ueda, Kazushige; Inaguma, Yoshiyuki


    To understand luminescent mechanisms of lanthanide (Ln) doped phosphors, it is important to know the energy positions of unoccupied Ln2+ 4f and Ln3+ 5d states, as well as occupied Ln3+ 4f states, relative to the energy bands of host materials. Photoluminescence excitation (PLE) spectra of Ln doped YAlO3 were measured in a vacuum ultraviolet (VUV) region and the energy positions of Ln2+ 4f and Ln3+ 5d states in the wide-gap YAlO3 were elucidated. Peaks assignable to host lattice excitation were observed in all samples at approximately 8 eV in the PLE spectra. PLE peaks derived from charge transfer (CT) and 4f-5d transitions were observed at lower energy than the bandgap energy. Ln2+ 4f energy levels were obtained from the PLE peak energies for the CT transitions along with the valence band maximum. In contrast, Ln3+ 5d energy levels were evaluated from those for the 4f-5d transitions along with the Ln3+ 4f energy levels, which were obtained previously from X-ray photoelectron spectroscopy measurements. The elucidated Ln2+ 4f and Ln3+ 5d energy levels were exhibited in an energy diagram together with Ln3+ 4f energy levels and host energy bands. The experimental Ln2+ 4f and Ln3+ 5d energy levels were in good agreement with the reported theoretical data.

  14. Solid state direct bonding of polymers by vacuum ultraviolet light below 160 nm (United States)

    Hashimoto, Yuki; Yamamoto, Takatoki


    This work investigated the application of vacuum ultraviolet (VUV) irradiation to the bonding of various substrates, including glass, polycarbonate (PC), cyclic olefin polymer (COP), polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA). This method has the advantage of being able to bond various substrates without the application of heat or adhesives, and therefore may be very useful in the fabrication of micro/nanoscale structures composed of polymers. In contrast to previous applications of this technique, the present study used VUV radiation at wavelengths at and below 160 nm so as to take advantage of the higher energy in this range. Bonding was assessed based on measuring the shear stress of various test specimens subjected to VUV irradiation and then pressed together, and a number of analytical methods were also employed to examine the irradiated surfaces in order to elucidate the morphological and chemical changes following VUV treatment. These analyses included water contact angle measurements, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), time of flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM). Poor bonding was identified between combinations consisting of PMMA/PC, PMMA/COP, PMMA/PMMA, PMMA/glass, and PC/COP, whereas all other combinations resulted in successful bonding with the bonding stress values such as PC/PC = 2.0 MPa, PC/glass = 10.7 MPa and COP/COP = 1.7 MPa, respectively.

  15. Internal Energies of Ion-Sputtered Neutral Tryptophan and Thymine Molecules Determined by Vacuum Ultraviolet Photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jia; Takahashi, Lynelle; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid


    Vacuum ultraviolet photoionization coupled to secondary neutral mass spectrometry (VUV-SNMS) of deposited tryptophan and thymine films are performed at the Chemical Dynamics Beamline. The resulting mass spectra show that while the intensity of the VUV-SNMS signal is lower than the corresponding secondary ion mass spectroscopy (SIMS) signal, the mass spectra are significantly simplified in VUV-SNMS. A detailed examination of tryptophan and thymine neutral molecules sputtered by 25 keV Bi3 + indicates that the ion-sputtered parent molecules have ~;;2.5 eV of internal energy. While this internal energy shifts the appearance energy of the photofragment ions for both tryptophan and thymine, it does not change the characteristic photoionizaton efficiency (PIE) curves of thymine versus photon energy. Further analysis of the mass spectral signals indicate that approximately 80 neutral thymine molecules and 400 tryptophan molecules are sputtered per incident Bi3 + ion. The simplified mass spectra and significant characteristic ion contributions to the VUV-SNMS spectra indicate the potential power of the technique for organic molecule surface analysis.

  16. Ultraviolet-visible spectroscopy of graphene oxides

    Directory of Open Access Journals (Sweden)

    Qi Lai


    Full Text Available Dispersions of few-layer (1-3 layers, multi-layer (4-10 layers and thick-layer (>10 layers graphene oxide (GO were prepared by a modified Hummers method with different mass ratios of KMnO4 to graphite. Ultraviolet-visible (UV-vis spectroscopic data show that few-layer GO dispersions can be distinguished from multi- and thick-layer dispersions by a more intense peak at 230 nm. Atomic force microscopy (AFM images of few-layer GO contain a single peak, those of multi-layer GO exhibit a shoulder and those of thick-layer GO do not contain a peak or shoulder. These findings allow qualitative analysis of GO dispersions. X-ray photoelectron spectra (XPS show that the change of UV-vis absorption intensity of GO is caused by a conjugative effect related to chromophore aggregation that influences the π-π* plasmon peak.

  17. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.


    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

  18. Vacuum ultraviolet and visible spectra of ZnO:Eu{sup 3+} prepared by combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Bingming [National Synchrotron Radiation Research Centre, Hsinchu, Taiwan (China); Yu Lixin; Duan Changkui; Wang, Huaishan; Tanner, Peter A [Department of Biology and Chemistry, City University of Hong Kong, Kowloon (Hong Kong)], E-mail:


    Zinc oxide doped with 1 at.% Eu{sup 3+} has been prepared by combustion synthesis using several different reductants. Samples sintered at 800 deg. C were {approx}30 nm in size and Fourier transform IR spectra demonstrated that they were relatively free of contaminants. Ultraviolet and near-ultraviolet laser excited emission spectra showed that Eu{sup 3+} ions are disordered and not situated at discrete lattice sites in ZnO and consequently no evidence for energy transfer from the host to Eu{sup 3+} was found. Vacuum ultraviolet (VUV) excitation produced defect site emission in addition to near-band-edge emission but the intensity of the Eu{sup 3+} visible emission was very weak. Bands between 6.2 and 9.1 eV in the VUV excitation spectra have been assigned to electric dipole allowed transitions, 3d-4p.

  19. Ultraviolet Spectroscopy of Tidal Disruption Flares (United States)

    Cenko, Stephen B.


    When a star passes within the sphere of disruption of a massive black hole, tidal forces will overcome self-gravity and unbind the star. While approximately half of the stellar debris is ejected at high velocities, the remaining material stays bound to the black hole and accretes, resulting in a luminous, long-lived transient known as a tidal disruption flare (TDF). In addition to serving as unique laboratories for accretion physics,TDFs offer the hope of measuring black hole masses in galaxies much too distant for resolved kinematic studies.In order to realize this potential, we must better understand the detailed processes by which the bound debris circularizes and forms an accretion disk. Spectroscopy is critical to this effort, as emission and absorption line diagnostics provide insight into the location and physical state (velocity, density, composition) of the emitting gas (in analogy with quasars). UV spectra are particularly critical, as most strong atomic features fall in this bandpass, and high-redshift TDF discoveries from LSST will sample rest-frame UV wavelengths.Here I present recent attempts to obtain UV spectra of tidal disruption flares. I describe the UV spectrum of ASASSN-14li, in which we detect three classes of features: narrow absorption from the Milky Way (probably a high-velocity cloud), and narrow absorption and broad (2000-8000 km s-1) emission lines at or near the systemic host velocity. The absorption lines are blueshifted with respect to the emission lines by 250-400 km s-1. Due both to this velocity offset and the lack of common low-ionization features (Mg II, Fe II), we argue these arise from the same absorbing material responsible for the low-velocity outflow discovered at X-ray wavelengths. The broad nuclear emission lines display a remarkable abundance pattern: N III], N IV], and He II are quite prominent, while the common quasar emission lines of C III] and Mg II are weak or entirely absent. Detailed modeling of this spectrum will

  20. Resonance ionization spectroscopy using ultraviolet laser

    CERN Document Server

    Han, J M; Ko, D K; Park, H M; Rhee, Y J


    In this study, Ti:sapphire laser which is pumped by the enhanced Nd:YAG laser using laser diode, was designed and manufactured. The AO Q-switched CW Nd:YAG laser was converted into a high repetition plus-type laser using the AO Q-switch, and two heads were installed inside the cavity in order to improve the laser beam quality. The Nd:YAG laser enhancement was completed by optimization using a simulation for the cavity length, structure and thermal lens effect that greatly effected the laser beam output and quality. As the result of the enhancement, a 30W laser at 532nm and at 5k-Hz was successfully made. Also, the Ti:sapphire laser that will be used for atomic spectroscopy which is pumped by the Nd:YAG laser, was completely designed. As a basic experiment for laser oscillation. We measured the tunability of the laser, and it turned out that the wave tunability range was 730 850 nm. A self-seeding type tunable laser using grating for narrow line width, is planned to be designed due to the fact that the Ti:sapp...

  1. Luminescence properties of organic–inorganic layered perovskite-type compounds under vacuum ultraviolet irradiation (United States)

    Kawano, Naoki; Koshimizu, Masanori; Okada, Go; Fujimoto, Yutaka; Kawaguchi, Noriaki; Yanagida, Takayuki; Asai, Keisuke


    We investigated the luminescence properties of organic–inorganic layered perovskite-type compounds under vacuum ultraviolet irradiation. A crystal of (C6H5C2H4NH3)2PbBr4 was fabricated by the poor-solvent diffusion method. Exciton emissions from the inorganic layer were observed at 410 nm under ultraviolet irradiation (excitation wavelengths: 180 and 300 nm). The rise time behavior observed in the luminescence decay curve showed no difference among the excitation wavelengths of 60–300 nm. In addition, no excitation peak of benzene such as an intense peak at 180 nm (1A1g → 1E1u) in the vacuum ultraviolet region was observed in the excitation spectra measured while monitoring the exciton emissions from the inorganic layer. These results indicate that the effect of energy transfer from the organic layer to the inorganic layer has negligible contribution to the luminescence properties of organic–inorganic layered perovskite-type compounds.

  2. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids (United States)

    Jablonowski, H.; Bussiahn, R.; Hammer, M. U.; Weltmann, K.-D.; von Woedtke, Th.; Reuter, S.


    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100-400 nm) and, in particular, vacuum ultraviolet (VUV, 10-200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH2O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H2O2) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O2•-) and hydroxyl radicals (•OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  3. Impact of plasma jet vacuum ultraviolet radiation on reactive oxygen species generation in bio-relevant liquids

    Energy Technology Data Exchange (ETDEWEB)

    Jablonowski, H.; Hammer, M. U.; Reuter, S. [Center for Innovation Competence plasmatis, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Bussiahn, R.; Weltmann, K.-D.; Woedtke, Th. von [Leibniz Institute for Plasma Science and Technology, INP Greifswald e.V. Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)


    Plasma medicine utilizes the combined interaction of plasma produced reactive components. These are reactive atoms, molecules, ions, metastable species, and radiation. Here, ultraviolet (UV, 100–400 nm) and, in particular, vacuum ultraviolet (VUV, 10–200 nm) radiation generated by an atmospheric pressure argon plasma jet were investigated regarding plasma emission, absorption in a humidified atmosphere and in solutions relevant for plasma medicine. The energy absorption was obtained for simple solutions like distilled water (dH{sub 2}O) or ultrapure water and sodium chloride (NaCl) solution as well as for more complex ones, for example, Rosewell Park Memorial Institute (RPMI 1640) cell culture media. As moderate stable reactive oxygen species, hydrogen peroxide (H{sub 2}O{sub 2}) was studied. Highly reactive oxygen radicals, namely, superoxide anion (O{sub 2}{sup •−}) and hydroxyl radicals ({sup •}OH), were investigated by the use of electron paramagnetic resonance spectroscopy. All species amounts were detected for three different treatment cases: Plasma jet generated VUV and UV radiation, plasma jet generated UV radiation without VUV part, and complete plasma jet including all reactive components additionally to VUV and UV radiation. It was found that a considerable amount of radicals are generated by the plasma generated photoemission. From the experiments, estimation on the low hazard potential of plasma generated VUV radiation is discussed.

  4. Possibility of using sources of vacuum ultraviolet irradiation to solve problems of space material science (United States)

    Verkhoutseva, E. T.; Yaremenko, E. I.


    An urgent problem in space materials science is simulating the interaction of vacuum ultraviolet (VUV) of solar emission with solids in space conditions, that is, producing a light source with a distribution that approximates the distribution of solar energy. Information is presented on the distribution of the energy flux of VUV of solar radiation. Requirements that must be satisfied by the VUV source used for space materials science are formulated, and a critical evaluation is given of the possibilities of using existing sources for space materials science. From this evaluation it was established that none of the sources of VUV satisfies the specific requirements imposed on the simulator of solar radiation. A solution to the problem was found to be in the development of a new type of source based on exciting a supersonic gas jet flowing into vacuum with a sense electron beam. A description of this gas-jet source, along with its spectral and operation characteristics, is presented.

  5. Absolute vacuum ultraviolet flux in inductively coupled plasmas and chemical modifications of 193 nm photoresist (United States)

    Titus, M. J.; Nest, D.; Graves, D. B.


    Vacuum ultraviolet (VUV) photons in plasma processing systems are known to alter surface chemistry and may damage gate dielectrics and photoresist. We characterize absolute VUV fluxes to surfaces exposed in an inductively coupled argon plasma, 1-50 mTorr, 25-400 W, using a calibrated VUV spectrometer. We also demonstrate an alternative method to estimate VUV fluence in an inductively coupled plasma (ICP) reactor using a chemical dosimeter-type monitor. We illustrate the technique with argon ICP and xenon lamp exposure experiments, comparing direct VUV measurements with measured chemical changes in 193 nm photoresist-covered Si wafers following VUV exposure.

  6. CIV Polarization Measurements using a Vacuum Ultraviolet Fabry-Perot Interferometer (United States)

    West, Edward; Gary, G. Allen; Cirtain, Jonathan; David, John; Kobayashi, Ken; Pietraszewski, Chris


    Marshall Space Flight Center's (MSFC) is developing a Vacuum Ultraviolet (VUV) Fabry-P rot Interferometer that will be launched on a sounding rocket for high throughput, high-cadence, extended field of view CIV (155nm) measurements. These measurements will provide (i) Dopplergrams for studies of waves, oscillations, explosive events, and mass motions through the transition region, and, (ii), polarization measurements to study the magnetic field in the transition region. This paper will describe the scientific goals of the instrument, a brief description of the optics and the polarization characteristics of the VUV Fabry P rot.

  7. Vacuum ultraviolet light source utilizing rare gas scintillation amplification sustained by photon positive feedback (United States)

    Aprile, Elena (Inventor); Chen, Danli (Inventor)


    A source of light in the vacuum ultraviolet (VUV) spectral region includes a reflective UV-sensitive photocathode supported in spaced parallel relationship with a mesh electrode within a rare gas at low pressure. A high positive potential applied to the mesh electrode creates an electric field which causes drifting of free electrons occurring between the electrodes and producing continuous VUV light output by electric field-driven scintillation amplification sustained by positive photon feedback mediated by photoemission from the photocathode. In one embodiment the lamp emits a narrow-band continuum peaked at 175 nm.

  8. Energetics, ionization, and expansion dynamics of atomic clusters irradiated with short intense vacuum-ultraviolet pulses. (United States)

    Ziaja, B; Wabnitz, H; Wang, F; Weckert, E; Möller, T


    Kinetic equations are used to model the dynamics of Xe clusters irradiated with short, intense vacuum-ultraviolet pulses. Various cluster size and pulse fluences are considered. It is found that the highly charged ions observed in the experiments are mainly due to Coulomb explosion of the outer cluster shell. Ions within the cluster core predominantly recombine with plasma electrons, forming a large fraction of neutral atoms. To our knowledge, our model is the first and only one that gives an accurate description of all of the experimental data collected from atomic clusters at 100 nm photon wavelength.

  9. CIV Vacuum Ultraviolet Fabry-Perot Interferometers for Transition-Region Magnetography (United States)

    Gary, G. Allen; West, Edward A.; Rees, David; Zukic, Maumer; Herman, Peter; Li, Jianzhao


    The vacuum ultraviolet region allows remote sensing of the upper levels of the solar atmosphere where the magnetic field dominates the physics. Obtaining an imaging interferometer that observes the transition region is the goal of this program. This paper gives a summary of our instrument development program (1998-2005) for a high-spectral-resolution, piezoelectric tunable Vacuum Ultraviolet Fabry-Perot Interferometer (VUV FPI) for obtaining narrow-passband images, magnetograms, and Dopplergrams of the transition region emission line of CN (155nm). A VUV interferometer will allow us to observe the magnetic field, flows, and heating events in the mid-transition region. The MSFC VUV FPI has measured values of FWHM approx. 9pm, FSR approx. 62pm, finesse approx. 5.3 and transmittance approx. 50% at 157nm. For the measurements, the University of Toronto's F2 eximer laser was used as an appropriate proxy for CIV 155nm. This has provided the first tunable interferometer with a FWHM compatible to VUV filter magnetograph.

  10. [Design and study of a high resolution vacuum ultraviolet imaging spectrometer carried by satellite]. (United States)

    Yu, Lei; Lin, Guan-yu; Qu, Yi; Wang, Shu-rong; Wang, Long-qi


    A high resolution vacuum ultraviolet imaging spectrometer prototype carried by satellite applied to the atmosphere detection of particles distribution in 115-300 nm was developed for remote sensing. First, based on the analysis of advanced loads, the optical system including an off-axis parabolic mirror as the telescope and Czerny-Turner structure as the imaging spectrometer was chosen Secondly, the 2-D photon counting detector with MCP was adopted for the characteristic that the radiation is weak in vacuum ultraviolet waveband. Then the geometric method and 1st order differential calculation were introduced to improve the disadvantages that aberrations in the traditional structure can not be corrected homogeneously to achieve perfect broadband imaging based on the aberration theory. At last, an advanced example was designed. The simulation and calculation of results demonstrate that the modulation transfer function (MTF) of total field of view is more than 0.6 in the broadband, and the spectral resolution is 1.23 nm. The structure is convenient and predominant. It proves that the design is feasible.

  11. Simultaneous removal of NO and SO2 using vacuum ultraviolet light (VUV)/heat/peroxymonosulfate (PMS). (United States)

    Liu, Yangxian; Wang, Yan; Wang, Qian; Pan, Jianfeng; Zhang, Jun


    Simultaneous removal process of SO2 and NO from flue gas using vacuum ultraviolet light (VUV)/heat/peroxymonosulfate (PMS) in a VUV spraying reactor was proposed. The key influencing factors, active species, reaction products and mechanism of SO2 and NO simultaneous removal were investigated. The results show that vacuum ultraviolet light (185 nm) achieves the highest NO removal efficiency and yield of and under the same test conditions. NO removal is enhanced at higher PMS concentration, light intensity and oxygen concentration, and is inhibited at higher NO concentration, SO2 concentration and solution pH. Solution temperature has a double impact on NO removal. CO2 concentration has no obvious effect on NO removal. and produced from VUV-activation of PMS play a leading role in NO removal. O3 and ·O produced from VUV-activation of O2 also play an important role in NO removal. SO2 achieves complete removal under all experimental conditions due to its very high solubility in water and good reactivity. The highest simultaneous removal efficiency of SO2 and NO reaches 100% and 91.3%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Laser Desorption Postionization Mass Spectrometry of Antibiotic-Treated Bacterial Biofilms using Tunable Vacuum Ultraviolet Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Gasper, Gerald L; Takahashi, Lynelle K; Zhou, Jia; Ahmed, Musahid; Moore, Jerry F; Hanley, Luke


    Laser desorption postionization mass spectrometry (LDPI-MS) with 8.0 ? 12.5 eV vacuum ultraviolet synchrotron radiation is used to single photon ionize antibiotics andextracellular neutrals that are laser desorbed both neat and from intact bacterial biofilms. Neat antibiotics are optimally detected using 10.5 eV LDPI-MS, but can be ionized using 8.0 eV radiation, in agreement with prior work using 7.87 eV LDPI-MS. Tunable vacuum ultraviolet radiation also postionizes laser desorbed neutrals of antibiotics and extracellular material from within intact bacterial biofilms. Different extracellular material is observed by LDPI-MS in response to rifampicin or trimethoprim antibiotic treatment. Once again, 10.5 eV LDPI-MS displays the optimum trade-off between improved sensitivity and minimum fragmentation. Higher energy photons at 12.5 eV produce significant parent ion signal, but fragment intensity and other low mass ions are also enhanced. No matrix is added to enhance desorption, which is performed at peak power densities insufficient to directly produce ions, thus allowing observation of true VUV postionization mass spectra of antibiotic treated biofilms.

  13. Absolute calibration of a hydrogen discharge lamp in the vacuum ultraviolet (United States)

    Nealy, J. E.


    A low-pressure hydrogen discharge lamp was calibrated for radiant intensity in the vacuum ultraviolet spectral region on an absolute basis and was employed as a laboratory standard source in spectrograph calibrations. This calibration was accomplished through the use of a standard photodiode detector obtained from the National Bureau of Standards together with onsite measurements of spectral properties of optical components used. The stability of the light source for use in the calibration of vacuum ultraviolet spectrographs and optical systems was investigated and found to be amenable to laboratory applications. The lamp was studied for a range of operating parameters; the results indicate that with appropriate peripheral instrumentation, the light source can be used as a secondary laboratory standard source when operated under preset controlled conditions. Absolute intensity measurements were recorded for the wavelengths 127.7, 158.0, 177.5, and 195.0 nm for a time period of over 1 month, and the measurements were found to be repeatable to within 11 percent.

  14. Ultraviolet-vacuum ultraviolet photoluminescence and x ray radioluminescence of Ce3+-doped Ba3MgSi2O8

    NARCIS (Netherlands)

    Ding, X.; Liang, H.; Hou, D.; Su, Q.; Dorenbos, P.; Sun, S.; Tao, Y.


    Ce3+-doped Ba3MgSi2O8 phosphors were prepared by a solid-state reaction route. The photoluminescence properties in the vacuum ultraviolet-vis spectral range and the x ray excited radioluminescence were investigated. Ce3+ ions were found to enter three different sites in the host lattice. Five

  15. Extreme ultraviolet high-harmonic spectroscopy of solids. (United States)

    Luu, T T; Garg, M; Kruchinin, S Yu; Moulet, A; Hassan, M Th; Goulielmakis, E


    Extreme ultraviolet (EUV) high-harmonic radiation emerging from laser-driven atoms, molecules or plasmas underlies powerful attosecond spectroscopy techniques and provides insight into fundamental structural and dynamic properties of matter. The advancement of these spectroscopy techniques to study strong-field electron dynamics in condensed matter calls for the generation and manipulation of EUV radiation in bulk solids, but this capability has remained beyond the reach of optical sciences. Recent experiments and theoretical predictions paved the way to strong-field physics in solids by demonstrating the generation and optical control of deep ultraviolet radiation in bulk semiconductors, driven by femtosecond mid-infrared fields or the coherent up-conversion of terahertz fields to multi-octave spectra in the mid-infrared and optical frequencies. Here we demonstrate that thin films of SiO2 exposed to intense, few-cycle to sub-cycle pulses give rise to wideband coherent EUV radiation extending in energy to about 40 electronvolts. Our study indicates the association of the emitted EUV radiation with intraband currents of multi-petahertz frequency, induced in the lowest conduction band of SiO2. To demonstrate the applicability of high-harmonic spectroscopy to solids, we exploit the EUV spectra to gain access to fine details of the energy dispersion profile of the conduction band that are as yet inaccessible by photoemission spectroscopy in wide-bandgap dielectrics. In addition, we use the EUV spectra to trace the attosecond control of the intraband electron motion induced by synthesized optical transients. Our work advances lightwave electronics in condensed matter into the realm of multi-petahertz frequencies and their attosecond control, and marks the advent of solid-state EUV photonics.

  16. Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy (United States)

    Pugel, Betsy


    A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes. The ultraviolet source is used to illuminate a composite surface of interest. In reflectance mode, the reflected response is acquired via the imaging system or via the spectrometer. The spectra are analyzed for organic compounds (conjugated organics) and inorganic compounds (semiconducting band-edge states; luminescing defect states such as silicates, used as adhesives for composite aerospace applications; and metal oxides commonly used as thermal coating paints on a wide range of spacecraft). The spectra are compared with a database for variation in conjugation, substitution, or length of molecule (in the case of organics) or band edge position (in the case of inorganics). This approach is useful in the understanding of material quality. It lacks the precision in defining the exact chemical structure that is found in other materials analysis techniques, but it is advantageous over methods such as nuclear magnetic resonance, infrared spectroscopy, and chromatography in that it can be used in the field to assess significant changes in chemical structure that may be linked to concerns associated with weaknesses or variations in structural integrity, without disassembly of or destruction to the structure of interest.

  17. Ultra-fast switching of light by absorption saturation in vacuum ultra-violet region. (United States)

    Yoneda, Hitoki; Inubushi, Yuichi; Tanaka, Toshihiro; Yamaguchi, Yuta; Sato, Fumiya; Morimoto, Shunsuke; Kumagai, Taisuke; Nagasono, Mitsuru; Higashiya, Atsushi; Yabashi, Makina; Ishikawa, Tetsuya; Ohashi, Haruhiko; Kimura, Hiroaki; Kitamura, Hikaru; Kodama, Ryosuke


    Advances in free electron lasers producing high energy photons [Nat. Photonics 2(9), 555-559 (2008)] are expected to open up a new science of nonlinear optics of high energy photons. Specifically, lasers of photon energy higher than the plasma frequency of a metal can show new interaction features because they can penetrate deeply into metals without strong reflection. Here we show the observation of ultra-fast switching of vacuum ultra-violet (VUV) light caused by saturable absorption of a solid metal target. A strong gating is observed at energy fluences above 6J/cm2 at wavelength of 51 nm with tin metal thin layers. The ratio of the transmission at high intensity to low intensity is typically greater than 100:1. This means we can design new nonlinear photonic devices such as auto-correlator and pulse slicer for the VUV region.

  18. Photofragmentation of gas-phase acetic acid and acetamide clusters in the vacuum ultraviolet region (United States)

    Berholts, Marta; Myllynen, Hanna; Kooser, Kuno; Itälä, Eero; Granroth, Sari; Levola, Helena; Laksman, Joakim; Oghbaiee, Shabnam; Oostenrijk, Bart; Nõmmiste, Ergo; Kukk, Edwin


    Photofragmentation of gas-phase acetamide and acetic acid clusters produced by a supersonic expansion source has been studied using time-of-flight mass spectrometry and the partial ion yield (PIY) technique combined with tunable vacuum-ultraviolet synchrotron radiation. Appearance energies of the clusters and their fragments were experimentally determined from the PIY measurements. The effect of clusterization conditions on the formation and fragmentation of acetic acid clusters was investigated. Ab initio quantum mechanical calculations were performed on both samples' dimers to find their neutral and ionized geometries as well as proton transfer energy barriers leading to the optimal geometries. In the case of the acetamide dimer, the reaction resulting in the production of ammoniated acetamide was probed, and the geometry of the obtained ion was calculated.

  19. Fragmentation and dimerization of aliphatic amino acid films induced by vacuum ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masahito [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Tyuou-2, AIST, Umezono 1-1-1, Tsukuba, Ibaraki, 305-8568 (Japan)], E-mail:; Kaneko, Fusae [Graduate School of Science and Technology, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan); Koketsu, Toshiyuki [Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan); Nakagawa, Kazumichi [Graduate School of Science and Technology, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan); Graduate School of Human Development and Environment, Kobe University, Tsurukabuto 3-11, Nada-ku, Kobe 657-8501 (Japan); Yamada, Toru [Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Tyuou-2, AIST, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 (Japan)


    The chemical reaction of aliphatic amino acid, such as alanine (Ala) and leucine (Leu), in the solid phase induced by vacuum ultraviolet (VUV) irradiation was studied by high-performance liquid chromatography technique and mass spectroscopic method. Quantum efficiencies of dimerization of Ala in the solid phase obviously showed irradiated VUV wavelength dependence. The values of quantum efficiencies of formation of Ala dimer were determined to be 5.7x10{sup -5}, 1.3x10{sup -3}, and 2.4x10{sup -4} for 208, 183, and 87 nm irradiation, respectively. VUV-induced fragment desorption from Ala and Leu films has also been examined by mass spectroscopic method. Observed mass spectra clearly indicated that both the deamination and decarboxylation reactions were common in both Ala and Leu films, and the dissociation of side chain occurred only in Leu film.

  20. Two-dimensional vacuum ultraviolet images in different MHD events on the EAST tokamak (United States)

    Zhijun, WANG; Xiang, GAO; Tingfeng, MING; Yumin, WANG; Fan, ZHOU; Feifei, LONG; Qing, ZHUANG; EAST Team


    A high-speed vacuum ultraviolet (VUV) imaging telescope system has been developed to measure the edge plasma emission (including the pedestal region) in the Experimental Advanced Superconducting Tokamak (EAST). The key optics of the high-speed VUV imaging system consists of three parts: an inverse Schwarzschild-type telescope, a micro-channel plate (MCP) and a visible imaging high-speed camera. The VUV imaging system has been operated routinely in the 2016 EAST experiment campaign. The dynamics of the two-dimensional (2D) images of magnetohydrodynamic (MHD) instabilities, such as edge localized modes (ELMs), tearing-like modes and disruptions, have been observed using this system. The related VUV images are presented in this paper, and it indicates the VUV imaging system is a potential tool which can be applied successfully in various plasma conditions.

  1. Selective irradiation of radicals for biomedical treatment using vacuum ultraviolet light from an excimer lamp (United States)

    Ono, Ryo; Tokumitsu, Yusuke; Zen, Shungo; Yonemori, Seiya


    In plasma medicine, radicals are considered to play important roles. However, the medical effect of each radical, such as OH and O, is unknown. To examine the effect of each radical, selective production of radicals is needed. We developed selective production of radicals for biomedical treatment using a vacuum ultraviolet (VUV) light emitted from an excimer lamp. Selective irradiation of OH radicals can be achieved by irradiating the 172-nm VUV light from a Xe2 excimer lamp to a humid helium flow in a quartz tube. The water molecules are strongly photodissociated by the VUV light to produce OH radicals. A photochemical simulation for the selective OH production is developed to calculate the OH density. The calculated OH density is compared with OH density measured using laser-induced fluorescence (LIF). Selective production of other radicals than OH is also discussed.

  2. Vacuum ultraviolet circularly polarized coherent femtosecond pulses from laser seeded relativistic electrons

    Directory of Open Access Journals (Sweden)

    N. Čutić


    Full Text Available We have demonstrated the generation of circularly polarized coherent light pulses at 66 nm wavelength by combining laser seeding at 263 nm of a 375 MeV relativistic electron bunch with subsequent coherent harmonic generation from an elliptical undulator of APPLE-II type. Coherent pulses at higher harmonics in linear polarization have been produced and recorded up to the sixth order (44 nm. The duration of the generated pulses depends on the temporal overlap of the initial seed laser pulse and the electron bunch and was on the order of 200 fs. Currently, this setup is the only source worldwide producing coherent fs-light pulses with variable polarization in the vacuum ultraviolet.

  3. Vacuum Ultraviolet Field Emission Lamp Consisting of Neodymium Ion Doped Lutetium Fluoride Thin Film as Phosphor

    Directory of Open Access Journals (Sweden)

    Masahiro Yanagihara


    Full Text Available A vacuum ultraviolet (VUV field emission lamp was developed by using a neodymium ion doped lutetium fluoride (Nd3+ : LuF3 thin film as solid-state phosphor and carbon nanofiber field electron emitters. The thin film was synthesized by pulsed laser deposition and incorporated into the lamp. The cathodoluminescence spectra of the lamp showed multiple emission peaks at 180, 225, and 255 nm. These emission spectra were in good agreement with the spectra reported for the Nd3+ : LuF3 crystal. Moreover, application of an acceleration voltage effectively increased the emission intensity. These results contribute to the performance enhancement of the lamp operating in the VUV region.

  4. Si nanocrystals embedded in SiO2: Optical studies in the vacuum ultraviolet range

    DEFF Research Database (Denmark)

    Pankratov, V.; Osinniy, Viktor; Kotlov, A.


    Photoluminescence excitation and transmission spectra of Si nanocrystals of different diameters embedded in a SiO2 matrix have been investigated in the broad visible-vacuum ultraviolet spectral range using synchrotron radiation. The dependence of the photoluminescence excitation spectra...... on the nanocrystals size was experimentally established. It is shown that the photoluminescence excitation and absorption spectra are significantly blueshifted with decreasing Si nanocrystal size. A detailed comparison of photoluminescence excitation and absorption spectra with data from theoretical modeling has been...... done. It is demonstrated that the experimentally determined blueshift of the photoluminescence excitation and absorption spectra is larger than the theoretical predictions. The influence of point defects in the SiO2 matrix on the optical and luminescence properties of the embedded Si nanocrystals...

  5. Synchrotron Vacuum Ultraviolet Light and Soft X-Ray Radiation Effects on Aluminized Teflon FEP Investigated (United States)

    Dever, Joyce A.; Townsend, Jacqueline A.; Gaier, James R.; Jalics, Alice I.


    Since the Hubble Space Telescope (HST) was deployed in low Earth orbit in April 1990, two servicing missions have been conducted to upgrade its scientific capabilities. Minor cracking of second-surface metalized Teflon FEP (DuPont; fluorinated ethylene propylene) surfaces from multilayer insulation (MLI) was first observed upon close examination of samples with high solar exposure retrieved during the first servicing mission, which was conducted 3.6 years after deployment. During the second HST servicing mission, 6.8 years after deployment, astronaut observations and photographic documentation revealed significant cracks in the Teflon FEP layer of the MLI on both the solar- and anti-solar-facing surfaces of the telescope. NASA Goddard Space Flight Center directed the efforts of the Hubble Space Telescope MLI Failure Review Board, whose goals included identifying the low-Earth-orbit environmental constituent(s) responsible for the cracking and embrittling of Teflon FEP which was observed during the second servicing mission. The NASA Lewis Research Center provided significant support to this effort. Because soft x-ray radiation from solar flares had been considered as a possible cause for the degradation of the mechanical properties of Teflon FEP (ref. 1), the effects of soft xray radiation and vacuum ultraviolet light on Teflon FEP were investigated. In this Lewisled effort, samples of Teflon FEP with a 100-nm layer of vapor-deposited aluminum (VDA) on the backside were exposed to synchrotron radiation of various vacuum ultraviolet and soft x-ray wavelengths between 18 nm (69 eV) and 0.65 nm (1900 eV). Synchrotron radiation exposures were conducted using the National Synchrotron Light Source at Brookhaven National Laboratory. Samples of FEP/VDA were exposed with the FEP surface facing the synchrotron beam. Doses and fluences were compared with those estimated for the 20-yr Hubble Space Telescope mission.

  6. Permanent hydrophilic modification of polypropylene and poly(vinyl alcohol) films by vacuum ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Belmonte, Guilherme Kretzmann [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Charles, German [Centro de Química Aplicada (CEQUIMAP), Facultad de Ciencias Químicas, Unversidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Strumia, Miriam Cristina [Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IPQA-Conicet, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Weibel, Daniel Eduardo, E-mail: [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil)


    Highlights: • Polypropylene and Poly(vinyl alcohol) were surface modified by vacuum ultraviolet (VUV) irradiation. • The hydrophilicity of the treated films was permanent and resisted aging for several months. • Grafting of styrene monomer was only observed in the VUV irradiated regions. • The obtained results showed the potential in the use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region. - Abstract: Polypropylene (PP) and Poly(vinyl alcohol) (PVA) both synthetics polymers but one of them biodegradable, were surface modified by vacuum ultraviolet (VUV) irradiation. After VUV irradiation in an inert nitrogen atmosphere, the films were exposed to oxygen gas. The treated films were characterized by water contact angle measurements (WCA), optical profilometry, FTIR-ATR, XPS, UPS and NEXAFS techniques. PP and PVA VUV-treated films reached superhydrophilic conditions (WCAs <10°) in about 30 min of irradiation under our experimental conditions. It was observed that when the WCAs reached about 35–40° the hydrophilicity was permanent in both polymers. These results contrasted with typical plasma treatments were a rapid hydrophobic recovery with aging time is usually observed. UPS and XPS data showed the presence of new functionalities on the PP and PVA surfaces that were assigned to COO, C=O, C−O and C=C functional groups. Finally, grafting of styrene (ST) as a typical monomer was tested on PP films. It was confirmed that only in the VUV irradiated region an efficient grafting of ST or polymerized ST was found. Outside the irradiated regions no ST grafted was observed. Our results showed the potential use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region.

  7. Investigation of the Surface of Poly(ethylene terephthalate) Films Modified by Vacuum Ultraviolet Irradiation in Air

    NARCIS (Netherlands)

    Mitrofanov, A. V.; Karban, O. V.; Sugonyako, A.; Lubomska, M.

    This paper reports on the results of measuring the changes in the characteristics of the surface of poly(ethylene terephthalate) films upon radiation-induced oxidation of the polymer under vacuum ultraviolet irradiation in an oxygen-containing medium. The films were irradiated by light from a

  8. Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass (United States)

    X. Guo; J.E. Jakes; S. Banna; Y. Nishi; J.L. Shohet


    The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on the mechanical properties of low-k porous organosilicate glass (SiCOH) dielectric films were investigated. Nanoindentation measurements were made on SiCOH films before and after exposure to an electron-cyclotron-resonance plasma or a monochromatic synchrotron VUV beam, to determine the changes...

  9. Divertor extreme ultraviolet (EUV) survey spectroscopy in DIII-D (United States)

    McLean, Adam; Allen, Steve; Ellis, Ron; Jarvinen, Aaro; Soukhanovskii, Vlad; Boivin, Rejean; Gonzales, Eduardo; Holmes, Ian; Kulchar, James; Leonard, Anthony; Williams, Bob; Taussig, Doug; Thomas, Dan; Marcy, Grant


    An extreme ultraviolet spectrograph measuring resonant emissions of D and C in the lower divertor has been added to DIII-D to help resolve an 2X discrepancy between bolometrically measured radiated power and that predicted by boundary codes for DIII-D, JET and ASDEX-U. With 290 and 450 gr/mm gratings, the DivSPRED spectrometer, an 0.3 m flat-field McPherson model 251, measures ground state transitions for D (the Lyman series) and C (e.g., C IV, 155 nm) which account for >75% of radiated power in the divertor. Combined with Thomson scattering and imaging in the DIII-D divertor, measurements of position, temperature and fractional power emission from plasma components are made and compared to UEDGE/SOLPS-ITER. Mechanical, optical, electrical, vacuum, and shielding aspects of DivSPRED are presented. Work supported under USDOE Cooperative Agreement DE-FC02-04ER54698 and DE-AC52-07NA27344, and by the LLNL Laboratory Directed R&D Program, project #17-ERD-020.

  10. Transformation of porous structure under vacuum ultraviolet irradiation of the films based on silicon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Dultsev, F.N., E-mail: [Institute of Semiconductor Physics SB RAS, Novosibirsk 630090, Lavrentiev ave., 13 (Russian Federation); Novosibirsk State University, 630090, Novosibirsk (Russian Federation); Nekrasov, D.V. [Novosibirsk State University, 630090, Novosibirsk (Russian Federation)


    Transformation of the films with the pores of different radii under the action of vacuum ultraviolet radiation was studied experimentally and theoretically. Simulation results showed that Si–O–Si angle depends on pore size. Fourier Transform infrared spectra provide indirect confirmation of this statement. The experimental data and calculation results suggest that methyl group decreases π bonding, which causes a decrease in Si–O–Si angle. The action of ultraviolet radiation is to be considered as a photochemical reaction; the fragments formed in this reaction (CH{sub 3}{sup ⁎}, CH{sub 2}{sup ⁎}) can participate in polymerization, which leads to pore sealing. - Highlights: • Irradiation with the energy of 10–20 eV causes pore sealing. • FTIR studies and simulation results show that Si–O–Si angle depends on pore size. • Fragments formed in photochemical reaction (CH{sub 2}{sup ⁎}) can participate in polymerization. • Polymerization probability is high because the process takes place in closed space.

  11. Photochemistry of solid interstellar molecular samples exposed to vacuum-ultraviolet synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Jen-Iu; Chou, Sheng-Lung; Peng, Yu-Chain; Lin, Meng-Yeh; Lu, Hsiao-Chi; Cheng, Bing-Ming, E-mail:


    Highlights: • By means of an end station attached to synchrotron, we investigate the VUV photolysis of gaseous samples condensed at 3 K. • The end station is applicable to explore the VUV photochemistry of interstellar solid molecules. • We upgraded the end station with detection of absorption of IR light and of emission of UV–vis light. • As a demonstration, we recorded simultaneously absorption spectra of photoproduct N{sub 3} and emission from VUV excited N{sub 2}. • The end station is applicable to investigate cometary mixed-ice analogs excited with VUV light from the synchrotron. - Abstract: At the vacuum-ultraviolet (VUV) beamline of the Taiwan synchrotron, an end station for photochemistry coupled to instruments to record infrared absorption spectra and ultraviolet and visible emission spectra is used to investigate the photolysis of samples of gases condensed at 3 K. This end station is applicable to explore the VUV photochemistry of interstellar molecules in solid samples. For demonstration, we discuss the response of solid dinitrogen to VUV irradiation. In the future, the upgraded photochemistry end station is applicable to investigate the cometary mixed-ice analogs excited with VUV light from the synchrotron.

  12. [Luminescence properties of thenardite activated with Dy3+ under vacuum ultraviolet excitation]. (United States)

    Taximaiti, Yusufu; Ajimu, Abulai; Su, Zong-Cai; Aierken, Sidike


    Na2SO4: Dy3+ phosphors were prepared by heating pure natural thenardite (Na2SO4) with DyF3 at 900 degrees C for 25 min in air studied the Luminescence properties of Na2SO4: Dy3+ were studied by synchrotron radiation. Their photoluminescence (PL) spectra were also investigated under vacuum ultraviolet-ultraviolet (VUV-UV) at room temperature. According to the emission spectra, the yellow-blue ratio (Y/B) is different under different concentrations of Dy3+ and the position of excitation. And the excitation spectrum is consisted of strong bands assigned to the 4f9-->4f8 5d transition at 172 nm, the O(2-)- Tm3+ charge transfer band at 165 nm and weak bands assigned to host absorption (138, 245 nm) and the 6 H15/2-->4D7/2, 6H15/2-->6P3/2, and 6H15/2-->6P7/2 transition at 299, 325 and 351 nm respectively.

  13. Flash vacuum-ultraviolet source utilizing a surface-discharge substrate (United States)

    Sagae, Michiaki; Sato, Eiichi; Shikoda, Arimitsu; Oizumi, Teiji; Hayasi, Yasuomi; Shoji, Tetsuo; Shishido, Koro; Tamakawa, Yoshiharu; Yanagisawa, Toru


    The fundamental studies for the flash vacuum-ultraviolet (VUV) source utilizing a surface- discharge substrate are described. This flash VUV source consists of the following essential components: a high-voltage power supply, a polarity-inversion-type high-voltage pulser with a condenser capacity of 14.3 nF, an oil diffusion pump, and a flash VUV chamber with a glass body. The VUV chamber employed a surface-discharge ferrite substrate that's pattern was formed by means of the copper vacuum evaporation and was connected to an oil diffusion pump with a pressure of 1.3 X 10-3 Pa. The combined ceramic condenser in the pulser was charged from 10 to 30 kV by a power supply, and the electric charges in the condenser were discharged to the radiation chamber after closing a gap switch. Then the flash VUV rays were generated. The maximum values of the cathode voltage and the tube current were about -21 kV and 1.7 kA, respectively. The VUV outputs were measured by a combination of a plastic scintillator and a photomultiplier. The pulse durations of the VUV rays were nearly equivalent to the durations of the damped oscillations of the voltage and current, and their values were about 10 microsecond(s) .

  14. STUDENT AWARD FINALIST: Study of Self-Absorbed Vacuum Ultraviolet Radiation during Pulsed Atmospheric Breakdown in Air (United States)

    Laity, George; Fierro, Andrew; Hatfield, Lynn; Neuber, Andreas


    This paper describes recent experiments to investigate the role of self-produced vacuum ultraviolet (VUV) radiation in the physics of pulsed atmospheric breakdown. A unique apparatus was constructed which enables the detailed exploration of VUV light in the range 115-135 nm, which is emitted from breakdown between two point-point electrodes in an air environment at atmospheric pressure. Time-resolved diagnostics include VUV sensitive photomultipliers, intensified CCD imaging, optically isolated high voltage probes, and fast rise-time Rogowski current monitors. Temporally resolved spectroscopy from air breakdowns revealed VUV emission is released during the initial streamer phase before voltage collapse, with the majority of the emission lines identified from various atmospheric gases or surface impurities. Imaging of VUV radiation was performed which conserved the spatial emission profile, and distinct differences between nitrogen and oxygen VUV emission during onset of breakdown have been observed. Specifically, the self-absorption of HI, OI, and NI lines is addressed which elucidates the role of radiation transport during the photon-dominated streamer breakdown process. Supported by AFOSR, NASA / TSGC, DEPS, and IEEE DEIS.

  15. Effects of vacuum-ultraviolet irradiation on copper penetration into low-k dielectrics under bias-temperature stress

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Zheng, H.; Xue, P.; Shohet, J. L. [Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, S. W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Nishi, Y. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)


    The effects of vacuum-ultraviolet (VUV) irradiation on copper penetration into non-porous low-k dielectrics under bias-temperature stress (BTS) were investigated. By employing x-ray photoelectron spectroscopy depth-profile measurements on both as-deposited and VUV-irradiated SiCOH/Cu stacks, it was found that under the same BTS conditions, the diffusion depth of Cu into the VUV-irradiated SiCOH is higher than that of as-deposited SiCOH. On the other hand, under the same temperature-annealing stress (TS) without electric bias, the Cu distribution profiles in the VUV-irradiated SiCOH were same with that for the as-deposited SiCOH. The experiments suggest that in as-deposited SiCOH, the diffused Cu exists primarily in the atomic state, while in VUV-irradiated SiCOH, the diffused Cu is oxidized by the hydroxyl ions (OH{sup −}) generated from VUV irradiation and exists in the ionic state. The mechanisms for metal diffusion and ion injection in VUV irradiated low-k dielectrics are discussed.

  16. Vacuum Ultraviolet Radiation and Atomic Oxygen Durability Evaluation of HST Bi-Stem Thermal Shield Materials (United States)

    Dever, Joyce; deGroh, Kim K.


    Bellows-type thermal shields were used on the bi-stems of replacement solar arrays installed on the Hubble Space Telescope (HST) during the first HST servicing mission (SMI) in December 1993. These thermal shields helped reduce the problem of thermal gradient- induced jitter observed with the original HST solar arrays during orbital thermal cycling and have been in use on HST for eight years. This paper describes ground testing of the candidate solar array bi-stem thermal shield materials including backside aluminized Teflon(R)FEP (fluorinated ethylene propylene) with and without atomic oxygen (AO) and ultraviolet radiation protective surface coatings for durability to AO and combined AO and vacuum ultraviolet (VOV) radiation. NASA Glenn Research Center (GRC) conducted VUV and AO exposures of samples of candidate thermal shield materials at HST operational temperatures and pre- and post-exposure analyses as part of an overall program coordinated by NASA Goddard Space Flight Center (GSFC) to determine the on-orbit durability of these materials. Coating adhesion problems were observed for samples having the AO- and combined AO/UV-protective coatings. Coating lamination occurred with rapid thermal cycling testing which simulated orbital thermal cycling. This lack of adhesion caused production of coating flakes from the material that would have posed a serious risk to HST optics if the coated materials were used for the bi-stem thermal shields. No serious degradation was observed for the uncoated aluminized Teflon(R) as evaluated by optical microscopy, although atomic force microscopy (AFM) microhardness testing revealed that an embrittled surface layer formed on the uncoated Teflon(R) surface due to vacuum ultraviolet radiation exposure. This embrittled layer was not completely removed by AO erosion, No cracks or particle flakes were produced for the embrittled uncoated material upon exposure to VUV and AO at operational temperatures to an equivalent exposure of

  17. Ultraviolet refractometry using field-based light scattering spectroscopy (United States)

    Fu, Dan; Choi, Wonshik; Sung, Yongjin; Oh, Seungeun; Yaqoob, Zahid; Park, YongKeun; Dasari, Ramachandra R.; Feld, Michael S.


    Accurate refractive index measurement in the deep ultraviolet (UV) range is important for the separate quantification of biomolecules such as proteins and DNA in biology. This task is demanding and has not been fully exploited so far. Here we report a new method of measuring refractive index using field-based light scattering spectroscopy, which is applicable to any wavelength range and suitable for both solutions and homogenous objects with well-defined shape such as microspheres. The angular scattering distribution of single microspheres immersed in homogeneous media is measured over the wavelength range 260 to 315 nm using quantitative phase microscopy. By least square fitting the observed scattering distribution with Mie scattering theory, the refractive index of either the sphere or the immersion medium can be determined provided that one is known a priori. Using this method, we have measured the refractive index dispersion of SiO2 spheres and bovine serum albumin (BSA) solutions in the deep UV region. Specific refractive index increments of BSA are also extracted. Typical accuracy of the present refractive index technique is ≤0.003. The precision of refractive index measurements is ≤0.002 and that of specific refractive index increment determination is ≤0.01 mL/g. PMID:20372622

  18. Cell patterning using a template of microstructured organosilane layer fabricated by vacuum ultraviolet light lithography. (United States)

    Yamaguchi, Munehiro; Ikeda, Koji; Suzuki, Masaaki; Kiyohara, Ai; Kudoh, Suguru N; Shimizu, Kyoko; Taira, Toshio; Ito, Daisuke; Uchida, Tsutomu; Gohara, Kazutoshi


    Micropatterning techniques have become increasingly important in cellular biology. Cell patterning is achieved by various methods. Photolithography is one of the most popular methods, and several light sources (e.g., excimer lasers and mercury lamps) are used for that purpose. Vacuum ultraviolet (VUV) light that can be produced by an excimer lamp is advantageous for fabricating material patterns, since it can decompose organic materials directly and efficiently without photoresist or photosensitive materials. Despite the advantages, applications of VUV light to pattern biological materials are few. We have investigated cell patterning by using a template of a microstructured organosilane layer fabricated by VUV lithography. We first made a template of a microstructured organosilane layer by VUV lithography. Cell adhesive materials (poly(d-lysine) and polyethyleneimine) were chemically immobilized on the organosilane template, producing a cell adhesive material pattern. Primary rat cardiac and neuronal cells were successfully patterned by culturing them on the pattern substrate. Long-term culturing was attained for up to two weeks for cardiac cells and two months for cortex cells. We have discussed the reproducibility of cell patterning and made suggestions to improve it. © 2011 American Chemical Society

  19. Bipolar ionization source for ion mobility spectrometry based on vacuum ultraviolet radiation induced photoemission and photoionization. (United States)

    Chen, Chuang; Dong, Can; Du, Yongzhai; Cheng, Shasha; Han, Fenglei; Li, Lin; Wang, Weiguo; Hou, Keyong; Li, Haiyang


    A novel bipolar ionization source based on a commercial vacuum-UV Kr lamp has been developed for ion mobility spectrometry (IMS), which can work in both negative and positive ion mode. Its reactant ions formed in negative ion mode were predominantly assigned to be O(3)(-)(H(2)O)(n), which is different from that of the (63)Ni source with purified air as carrier and drift gases. The formation of O(3)(-)(H(2)O)(n) was due to the production of ozone caused by ultraviolet radiation, and the ozone concentration was measured to be about 1700 ppmv by iodometric titration method. Inorganic molecules such as SO(2), CO(2), and H(2)S can be easily detected in negative ion mode, and a linear dynamic range of 3 orders of magnitude and a limit of detection (S/N = 3) of 150 pptv were obtained for SO(2). Its performance as a negative ion source was investigated by the detection of ammonium nitrate fuel oil explosive, N-nitrobis(2-hydroxyethyl)amine dinitrate, cyclo-1,3,5-trimethylene-2,4,6-trinitramine, and pentaerythritol tetranitrate (PETN) at 150 degrees C. The limit of detection was reached at 45 pg for PETN, which was much lower than the 190 pg using (63)Ni ion mobility spectrometry under the same experimental condition. Also, its performance as an ordinary photoionization source was investigated in detecting benzene, toluene, and m-xylene.

  20. Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure and temperature dependency.

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Subrata; Davis, Ryan; Ahmed, Musahid; Jackson, Teresa L.; Thiemens, Mark H.


    Several absorption bands exist in the VUV region of Carbon monoxide (CO). Emission spectra indicate that these bands are all predissociative. An experimental investigation of CO photodissociation by vacuum ultraviolet photons (90 to 108 nm; ~13 to 11 eV) from the Advanced Light Source Synchrotron and direct measurement of the associated oxygen isotopic composition of the products are presented here. A wavelength dependency of the oxygen isotopic composition in the photodissociation product was observed. Slope values (δ'{sup 18}O/ δ'{sup 17}O) ranging from 0.76 to 1.32 were observed in oxygen three-isotope space (δ'{sup 18}O vs. δ'{sup 17}O) which correlated with increasing synchrotron photon energy, and indicate a dependency of the upper electronic state specific dissociation dynamics (e.g., perturbation and coupling associated with a particular state). An unprecedented magnitude in isotope separation was observed for photodissociation at the 105 and 107 nm synchrotron bands and are found to be associated with accidental predissociation of the vibrational states ({nu} = 0 and 1) of the upper electronic state E{sup 1}Π. For each synchrotron band, a large (few hundred per mil) extent of isotopic fractionation was observed and the range of fractionation is a combination of column density and exposure time. A significant temperature dependency in oxygen isotopic fractionation was observed, indicating a rotational level dependency in the predissociation process.

  1. On-line product analysis of pine wood pyrolysis using synchrotron vacuum ultraviolet photoionization mass spectrometry. (United States)

    Weng, Junjie; Jia, Liangyuan; Sun, Shaobo; Wang, Yu; Tang, Xiaofeng; Zhou, Zhongyue; Qi, Fei


    The pyrolysis process of pine wood, a promising biofuel feedstock, has been studied with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. The mass spectra at different photon energies and temperatures as well as time-dependent profiles of several selected species during pine wood pyrolysis process were measured. Based on the relative contents of three lignin subunits, the data indicate that pine wood is typical of softwood. As pyrolysis temperature increased from 300 to 700 °C, some more details of pyrolysis chemistry were observed, including the decrease of oxygen content in high molecular weight species, the observation of high molecular weight products from cellulose chain and lignin polymer, and potential pyrolysis mechanisms for some key species. The formation of polycyclic aromatic hydrocarbons (PAHs) was also observed, as well as three series of pyrolysis products derived from PAHs with mass difference of 14 amu. The time-dependent profiles show that the earliest products are formed from lignin, followed by hemicellulose products, and then species from cellulose.

  2. High-accuracy measurement of the emission spectrum of liquid xenon in the vacuum ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Keiko, E-mail: [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Endo, Yuya; Torigoe, Yui; Nakamura, Shogo [Faculty of Engineering, Yokohama National University, Yokohama, Kanagawa 240-8501 (Japan); Haruyama, Tomiyoshi; Kasami, Katsuyu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Mihara, Satoshi; Saito, Kiwamu; Sasaki, Shinichi [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); The Graduate School of Advanced Studies, Hayama, Kanagawa 240-0193 (Japan); Tawara, Hiroko [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan)


    The emission spectrum of cryogenic liquid xenon in the vacuum ultraviolet region was measured by irradiating liquid xenon with gamma-rays from a radioactive source. To achieve a high signal-to-noise ratio, we employed coincident photon counting. Additionally, the charge of the photo-sensor signals was measured to estimate the number of detected photons accurately. In addition, proper corrections were incorporated for the wavelength; response functions of the apparatus obtained using a low-pressure mercury lamp, and photon detection efficiencies of the optical system were considered. The obtained emission spectrum is found to be in the shape of a Gaussian function, with the center at 57,199±34 (stat.)±33 (syst.) cm{sup −1} (174.8±0.1 (stat.)±0.1 (syst.) nm) and the full width at half maximum of 3328±72 (stat.)±65 (syst.) cm{sup −1} (10.2±0.2 (stat.)±0.2 (sys.) nm). These results are the most accurate values obtained in terms of the data acquisition method and the calibration for the experimental system and provide valuable information regarding the high-precision instruments that employ a liquid-xenon scintillator.

  3. Determination of ionization energies of small silicon clusters with vacuum?ultraviolet (VUV) radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kostko, Oleg; Leone, Stephen R.; Duncan, Michael A.; Ahmed, Musahid


    In this work we report on single photon vacuum ultraviolet photoionization of small silicon clusters (n=1-7) produced via laser ablation of Si. The adiabatic ionization energies (AIE) are extracted from experimental photoionization efficiency (PIE) curves with the help of Frank?Condon simulations, used to interpret the shape and onset of the PIE curves. The obtained AIEs are (all energies are in eV): Si (8.13+-0.05), Si2 (7.92+-0.05), Si3 (8.12+-0.05), Si4 (8.2+-0.1), Si5 (7.96+-0.07), Si6 (7.8+-0.1), and Si7 (7.8+-0.1). Most of the experimental AIE values are in good agreement with ab initio electronic structure calculations. To explain observed deviations between the experimental and theoretical AIEs for Si4 and Si6, a theoretical search of different isomers of these species is performed. Electronic structure calculations aid in the interpretation of the a2PIu state of Si2+ dimer in the PIE spectrum. Time dependent density functional theory (TD-DFT) calculations are performed to reveal the energies of electronically excited states in the cations for a number of Si clusters.

  4. Control of the Polarization of a Vacuum-Ultraviolet, High-Gain, Free-Electron Laser

    Directory of Open Access Journals (Sweden)

    Enrico Allaria


    Full Text Available The two single-pass, externally seeded free-electron lasers (FELs of the FERMI user facility are designed around Apple-II-type undulators that can operate at arbitrary polarization in the vacuum ultraviolet-to-soft x-ray spectral range. Furthermore, within each FEL tuning range, any output wavelength and polarization can be set in less than a minute of routine operations. We report the first demonstration of the full output polarization capabilities of FERMI FEL-1 in a campaign of experiments where the wavelength and nominal polarization are set to a series of representative values, and the polarization of the emitted intense pulses is thoroughly characterized by three independent instruments and methods, expressly developed for the task. The measured radiation polarization is consistently >90% and is not significantly spoiled by the transport optics; differing, relative transport losses for horizontal and vertical polarization become more prominent at longer wavelengths and lead to a non-negligible ellipticity for an originally circularly polarized state. The results from the different polarimeter setups validate each other, allow a cross-calibration of the instruments, and constitute a benchmark for user experiments.

  5. The vacuum ultraviolet beamline/endstations at NSRL dedicated to combustion research. (United States)

    Zhou, Zhongyue; Du, Xuewei; Yang, Jiuzhong; Wang, Yizun; Li, Chaoyang; Wei, Shen; Du, Liangliang; Li, Yuyang; Qi, Fei; Wang, Qiuping


    An undulator-based vacuum ultraviolet (VUV) beamline (BL03U), intended for combustion chemistry studies, has been constructed at the National Synchrotron Radiation Laboratory (NSRL) in Hefei, China. The beamline is connected to the newly upgraded Hefei Light Source (HLS II), and could deliver photons in the 5-21 eV range, with a photon flux of 10(13) photons s(-1) at 10 eV when the beam current is 300 mA. The monochromator of the beamline is equipped with two gratings (200 lines mm(-1) and 400 lines mm(-1)) and its resolving power is 3900 at 7.3 eV for the 200 lines mm(-1) grating and 4200 at 14.6 eV for the 400 lines mm(-1) grating. The beamline serves three endstations which are designed for respective studies of premixed flame, fuel pyrolysis in flow reactor, and oxidation in jet-stirred reactor. Each endstation contains a reactor chamber, an ionization chamber where the molecular beam intersects with the VUV light, and a home-made reflectron time-of-flight mass spectrometer. The performance of the beamline and endstations with some preliminary results is presented here. The ability to detect reactive intermediates (e.g. H, O, OH and hydroperoxides) is advantageous in combustion chemistry research.

  6. Sterilization of Bacillus atrophaeus using OH radicals supplied by vacuum ultraviolet method (United States)

    Yonetamari, Kenta; Tokumitsu, Yusuke; Yonemori, Seiya; Ono, Ryo; Yasuda, Hachiro; Mizuno, Akira


    Sterilization by cold plasma has widely been performed. It is well known that reactive oxygen species (ROS) has a potential of sterilization. However, it is not clear which ROS is effective on sterilization because a lot of types of ROS are produced in plasma. In this study, sterilization effect of OH radicals by vacuum ultraviolet (VUV) method was investigated. This method utilizes photodissociation reaction to produce ROS so it can produce ROS selectively. Wet and dry helium with and without 1% O2 gas was used to demonstrate sterilization effect of OH radicals. Gases were flowed in a quartz tube (inner diameter 2 mm, outer diameter 4 mm) at a flow rate of 1.5 L/min. The produced ROS flowed out of the quartz tube nozzle. A Xe2 excimer lamp emitting 172 +/- 7 nm VUV light was placed parallel to the quartz tube with a distance of 8 mm. The distance between the lower end of the lamp and the nozzle of quartz tube was changed from 3 to 15 cm. As a target of sterilization, Bacillus atrophaeus (ATCC 9372) was used. The density of OH radicals was measured using laser-induced fluorescence (LIF). As a result, sterilization using VUV method was verified. This result showed that OH radicals sterilized the bacteria.

  7. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    Energy Technology Data Exchange (ETDEWEB)

    Niemi, K.; O' Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l' Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)


    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

  8. Photoluminescence performance of thulium doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} under irradiation of ultraviolet and vacuum ultraviolet lights

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaofeng [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Yezhou, E-mail: [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Liu, Xiong; Wei, Xingmin; Chen, Yueling; Zhou, Fei [Department of Science Teaching, Gansu University of Traditional Chinese Medicine, Lanzhou 730000 (China); Wang, Yuhua [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China)


    Highlights: • A novel blue-emitting phosphor Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was reported. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} exhibited excellent thermal and irradiation stability. • Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} was found to possess high color purity. - Abstract: In this work, we synthesized Tm{sup 3+} doped Li{sub 4}SrCa(SiO{sub 4}){sub 2} phosphors and investigated their photoluminescence properties under the excitation of ultraviolet and vacuum ultraviolet lights. The crystal structure analysis and variation of cell parameters confirm that Tm{sup 3+} ions have been successfully doped in the structure of Li{sub 4}SrCa(SiO{sub 4}){sub 2} host by occupying the sites of Ca{sup 2+} with the coordination number of 6. The luminescence results suggest that Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} is a good blue-emitting phosphor when excited by ultraviolet and vacuum ultraviolet irradiations. In addition, it is observed that there is nearly no degradation for Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} after undergoing thermal and irradiation treatments. Possible mechanisms for the luminescence processes are proposed on the basis of the discussion of excitation and emission spectra. In particular, the emission color of Li{sub 4}SrCa(SiO{sub 4}){sub 2}:Tm{sup 3+} by excitation of 147 and 172 nm irradiations is very close to the standard blue color, suggesting that it could be potentially applied in plasma display panels and mercury-free fluorescence lamps.

  9. Vacuum-Ultraviolet Photoionization and Mass Spectrometric Characterization of Lignin Monomers Coniferyl and Sinapyl Alcohols

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Lynelle K.; Zhou, Jia; Kostko, Oleg; Golan, Amir; Leone, Stephen R.; Ahmed, Musahid


    The fragmentation mechanisms of monolignols under various energetic processes are studied with jet-cooled thermal desorption molecular beam (TDMB) mass spectrometry (MS), 25 keV Bi3+ secondary ion MS (SIMS), synchrotron vacuum-ultraviolet secondary neutral MS (VUV-SNMS) and theoretical methods. Experimental and calculated appearance energies of fragments observed in TDMB MS indicate that the coniferyl alcohol photoionization mass spectra contain the molecular parent and several dissociative photoionization products. Similar results obtained for sinapyl alcohol are also discussed briefly. Ionization energies of 7.60 eV ? 0.05 eV for coniferyl alcohol and<7.4 eV for both sinapyl and dihydrosinapyl alcohols are determined. The positive ion SIMS spectrum of coniferyl alcohol shares few characteristic peaks (m/z = 137 and 151) with the TDMB mass spectra, shows extensive fragmentation, and does not exhibit clear molecular parent signals. VUV-SNMS spectra, on the other hand, are dominated by the parent ion and main fragments also present in the TDMB spectra. Molecular fragmentation in VUV-SNMS spectra can be reduced by increasing the extraction delay time. Some features resembling the SIMS spectra are also observed in the desorbed neutral products. The monolignol VUV-SNMS peaks shared with the TDMB mass spectra suggest that dissociative photoionization of ion-sputtered neutral molecules predominate in the VUV-SNMS mass spectra, despite the extra internal energy imparted in the initial ion impact. The potential applications of these results to imaging mass spectrometry of bio-molecules are discussed.

  10. Comparison of direct and alternating current vacuum ultraviolet lamps in atmospheric pressure photoionization. (United States)

    Vaikkinen, Anu; Haapala, Markus; Kersten, Hendrik; Benter, Thorsten; Kostiainen, Risto; Kauppila, Tiina J


    A direct current induced vacuum ultraviolet (dc-VUV) krypton discharge lamp and an alternating current, radio frequency (rf) induced VUV lamp that are essentially similar to lamps in commercial atmospheric pressure photoionization (APPI) ion sources were compared. The emission distributions along the diameter of the lamp exit window were measured, and they showed that the beam of the rf lamp is much wider than that of the dc lamp. Thus, the rf lamp has larger efficient ionization area, and it also emits more photons than the dc lamp. The ionization efficiencies of the lamps were compared using identical spray geometries with both lamps in microchip APPI mass spectrometry (μAPPI-MS) and desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS). A comprehensive view on the ionization was gained by studying six different μAPPI solvent compositions, five DAPPI spray solvents, and completely solvent-free DAPPI. The observed reactant ions for each solvent composition were very similar with both lamps except for toluene, which showed a higher amount of solvent originating oxidation products with the rf lamp than with the dc lamp in μAPPI. Moreover, the same analyte ions were detected with both lamps, and thus, the ionization mechanisms with both lamps are similar. The rf lamp showed a higher ionization efficiency than the dc lamp in all experiments. The difference between the lamp ionization efficiencies was greatest when high ionization energy (IE) solvent compositions (IEs above 10 eV), i.e., hexane, methanol, and methanol/water, (1:1 v:v) were used. The higher ionization efficiency of the rf lamp is likely due to the larger area of high intensity light emission, and the resulting larger efficient ionization area and higher amount of photons emitted. These result in higher solvent reactant ion production, which in turn enables more efficient analyte ion production. © 2012 American Chemical Society

  11. Flash vacuum-ultraviolet generator having a mercury-anode tube (United States)

    Sagae, Michiaki; Sato, Eiichi; Oizumi, Teiji; Yamamoto, Mariko; Takabe, Akihito; Sakamaki, Kimio; Ojima, Hidenori; Takayama, Kazuyoshi; Tamakawa, Yoshiharu; Yanagisawa, Toru


    The fundamental studies on a flash vacuum-ultraviolet (VUV) generator for producing water- window x rays are described. this generator consisted of the following essential components: a high-voltage power supply, a polarity-inversion-type high-voltage pulser having a 15 nF condenser, a thyristor pulser as a trigger device, a turbo molecular pump, and a VUV tube. The VUV tube employed a mercury anode, and the ferrite cathode was embedded in the anode. The pressure in the tube was primarily determined by the steam pressure of mercury as a function of temperature. The condenser in the pulser was charged from -10 to -30 kV by the power supply, and the electric charges in the condenser were discharged to the radiation tube after closing a gap switch by the thyristor pulser. As the high electron flows from the cathode electrode evaporated the anode electrode, VUV rays were then produced. The maximum output voltage from the pulser was approximately -1 times the charging voltage, and both the tube voltage and current displayed damped oscillations. The maximum values of the tube voltage and current were 14 kV and 2.0 kA, respectively. Since the effective accelerating voltage was substantially decreased by the ferrite cathode, soft x rays were easily generated. The pulse durations of the VUV rays including water-window x rays were nearly equivalent to those of the damped oscillations of the voltage and current, and their values were less than 15 microsecond(s) .

  12. Vacuum ultraviolet photon-mediated production of [18 F]F2. (United States)

    Krzyczmonik, Anna; Keller, Thomas; Kirjavainen, Anna K; Forsback, Sarita; Solin, Olof


    The chemistry of F2 and its derivatives are amenable to facile aliphatic or aromatic substitution, as well as electrophilic addition. The main limitation in the use of [18 F]F2 for radiopharmaceutical synthesis is the low specific activity achieved by the traditional methods of production. The highest specific activities, 55 GBq/μmol, for [18 F]F2 have been achieved so far by using electrical discharge in the post-target production of [18 F]F2 gas from [18 F]CH3 F. We demonstrate that [18 F]F2 is produced by illuminating a gas mixture of neon/F2 /[18 F]CH3 F with vacuum ultraviolet photons generated by an excimer laser. We tested several illumination chambers and production conditions. The effects of the initial amount of [18 F]F- , amount of carrier F2 , and number of 193-nm laser pulses at constant power were evaluated regarding radiochemical yield and specific activity. The specific activity attained for [18 F]F2 -derived [18 F]NFSi was 10.3 ± 0.9 GBq/μmol, and the average radiochemical yield over a wide range of conditions was 6.7% from [18 F]F- . The production can be improved by optimization of the synthesis device and procedures. The use of a commercially available excimer laser and the simplicity of the process can make this method relatively easy for adaptation in radiochemistry laboratories. Copyright © 2017 The Authors. Journal of Labelled Compounds and Radiopharmaceuticals Published by John Wiley & Sons, Ltd.

  13. Sulfur Isotopic Fractionation During Vacuum Ultraviolet Photolysis of SO2: Implication for Meteorites and Early Earth (United States)

    Chakraborty, S.; Jackson, T. L.; Rude, B.; Ahmed, M.; Thiemens, M. H.


    Several sulfur bearing gas phase species existed in the solar nebula, including H2S, SO2, SiS, OCS, CS2, CS, NS and SO as a consequence of multiple available chemical valence states (S2- to S6+). Sulfur directly condensed into refractory phases in the solar nebula under reducing conditions. Mass independent (MI) sulfur isotopic compositions have been measured in chondrules and organics from chondritic meteorites. Large 33S excesses in sulfides from achondrite meteoritic groups have also been found suggesting that refractory sulfide minerals condensed from a nebular gas with an enhanced carbon to oxygen ratio. Photochemical reactions in the early solar nebula have been inferred to be a leading process in generating MI sulfur compositions. Previously, we have reported wavelength dependent mass-independent sulfur isotopic compositions (with a varying degree in D33S and D36S) in the product elemental sulfur during vacuum ultraviolet (VUV) photodissociation of H2S. Recently we performed photodissociation of SO2 experiments in the wavelength region 98 to 200 nm at low pressures (0.5 torr) using the VUV photons from the Advanced Light Source Synchrotron in a differentially pumped reaction chamber. To our knowledge, this is the first ever experiment to determine the isotopic fractionation in VUV photodissociation of SO2. At VUV energy region, SO2 is mostly predissociative. The measured sulfur isotopic compositions in the product elemental sulfur are MI and dependent on the wavelength. These new results support the previous finding from photodissociation of other di- and tri-atomic molecules (CO, N2, H2S) that predissociative photodissociation produces MI isotopic products and is a quantum mechanically driven selective phenomenon. These new results are useful because (i) they are important in interpreting meteoritic data and decipher sulfur chemistry in the early nebula which is indicative of the redox condition of the nebula (ii) SO2 photolysis in the atmosphere of early

  14. Vacuum UV Polarization Spectroscopy of p-Terphenyl

    DEFF Research Database (Denmark)

    Nguyen, Duy Duc; Jones, Nykola C.; Hoffmann, Søren Vrønning


    p-Terphenyl is used as a component in a variety of optical devices. In this investigation, the electronic transitions of p-terphenyl are investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy in the range 30000 – 58000 cm–1 (330 – 170 nm) on molecular samples aligned in stretc...

  15. Ex situ elaborated proximity mesoscopic structures for ultrahigh vacuum scanning tunneling spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stolyarov, V. S. [UMR 7588, Institut des Nanosciences de Paris, UPMC Univ Paris 06, Sorbonne Universités, F-75005 Paris (France); CNRS, UMR 7588, Institut des Nanosciences de Paris, F-75005 Paris (France); Institute of Solid State Physics RAS, 142432 Chernogolovka (Russian Federation); Moscow Institute of Physics and Technology, 141700 Dolgoprudny (Russian Federation); Kazan Federal University, 420008 Kazan (Russian Federation); Moscow State University, 119991 Moscow (Russian Federation); Cren, T., E-mail:; Debontridder, F.; Brun, C. [UMR 7588, Institut des Nanosciences de Paris, UPMC Univ Paris 06, Sorbonne Universités, F-75005 Paris (France); CNRS, UMR 7588, Institut des Nanosciences de Paris, F-75005 Paris (France); Veshchunov, I. S. [Université de Bordeaux, LP2N, 351 cours de la Libération, F-33405 Talence (France); Institute of Solid State Physics RAS, 142432 Chernogolovka (Russian Federation); Skryabina, O. V. [Institute of Solid State Physics RAS, 142432 Chernogolovka (Russian Federation); Rusanov, A. Yu. [LLC “Applied radiophysics” 142432 Chernogolovka (Russian Federation); Roditchev, D. [UMR 7588, Institut des Nanosciences de Paris, UPMC Univ Paris 06, Sorbonne Universités, F-75005 Paris (France); CNRS, UMR 7588, Institut des Nanosciences de Paris, F-75005 Paris (France); LPEM-UMR 8213, CNRS, ESPCI-ParisTech, UPMC, 10 rue Vauquelin, F-75005 Paris (France)


    We apply ultrahigh vacuum Scanning Tunneling Spectroscopy (STS) at ultra-low temperature to study proximity phenomena in metallic Cu in contact with superconducting Nb. In order to solve the problem of Cu-surface contamination, Cu(50 nm)/Nb(100 nm) structures are grown by respecting the inverted order of layers on SiO{sub 2}/Si substrate. Once transferred into vacuum, the samples are cleaved at the structure-substrate interface. As a result, a contamination-free Cu-surface is exposed in vacuum. It enables high-resolution STS of superconducting correlations induced by proximity from the underlying superconducting Nb layer. By applying magnetic field, we generate unusual proximity-induced superconducting vortices and map them with a high spatial and energy resolution. The suggested method opens a way to access local electronic properties of complex electronic mesoscopic devices by performing ex situ STS under ultrahigh vacuum.

  16. Surface Emitting, High Efficiency Near-Vacuum Ultraviolet Light Source with Aluminum Nitride Nanowires Monolithically Grown on Silicon. (United States)

    Zhao, S; Djavid, M; Mi, Z


    To date, it has remained challenging to realize electrically injected light sources in the vacuum ultraviolet wavelength range (∼200 nm or shorter), which are important for a broad range of applications, including sensing, surface treatment, and photochemical analysis. In this Letter, we have demonstrated such a light source with molecular beam epitaxially grown aluminum nitride (AlN) nanowires on low cost, large area Si substrate. Detailed angle dependent electroluminescence studies suggest that, albeit the light is TM polarized, the dominant light emission direction is from the nanowire top surface, that is, along the c axis, due to the strong light scattering effect. Such an efficient surface emitting device was not previously possible using conventional c-plane AlN planar structures. The AlN nanowire LEDs exhibit an extremely large electrical efficiency (>85%), which is nearly ten times higher than the previously reported AlN planar devices. Our detailed studies further suggest that the performance of AlN nanowire LEDs is predominantly limited by electron overflow. This study provides important insight on the fundamental emission characteristics of AlN nanowire LEDs and also offers a viable path to realize an efficient surface emitting near-vacuum ultraviolet light source through direct electrical injection.

  17. Selective protein patterning based on the micro-structured organosilane self-assembled monolayer by vacuum ultraviolet light lithography. (United States)

    Lim, Sung-Hyuk; Yamaguchi, Munehiro; Nishimura, Okio; Mie, Yasuhiro; Tamura, Tomohiro; Kim, Byung-Woo; Suzuki, Masaaki


    We have succeeded to immobilize fluorescent proteins selectively using a micro-structured organosilane self-assembled monolayer as a template. An organosilane layer with amino terminal group was formed on a thermally oxidized Si wafer by liquid-phase method and then was pattern-etched by vacuum ultraviolet light (VUV). The second organosilane layer with thiol terminal group was deposited on the etched area by chemical vapor surface modification method (CVSM). These micro-structured organosilane layer containing two reactive terminal groups were chemically modified using bi-functional linkers. Two kinds of fluorescent protein, Enhanced Cyan Fluorescent Protein (ECFP) and R-phycoerythrin were selectively immobilized on the chemically modified surface.

  18. The characterization of selected drugs with infrared laser desorption/tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. (United States)

    Pan, Yang; Yin, Hao; Zhang, Taichang; Guo, Huijun; Sheng, Liusi; Qi, Fei


    Some selected drugs including captopril, fudosteine and racecadotril have been analyzed by infrared (IR) laser desorption/tunable synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (PIMS). The molecular ions of captopril and racecadotril are exclusively observed without any fragments at near threshold single-photon ionization (SPI). However, fudosteine easily forms fragments even at a photon energy near the ionization threshold, indicating the instability of its molecular ion. For these drugs, a number of fragments are yielded with the increase of photon energy. The structures of such fragments proposed by IR LD/VUV PIMS are supported by electron ionization time-of-flight mass spectrometry (EI-TOFMS) results. Fragmentation pathways are discussed in detail. Copyright (c) 2008 John Wiley & Sons, Ltd.

  19. Determination of the coherence length in the vacuum-ultraviolet spectral region for the BPO4 crystal (United States)

    Zhang, Xin; Wang, Guiling; Zhang, Shufeng; Zhang, Erpan; Wang, Lirong; Zhu, Yong; Wu, Yicheng; Chen, Chuangtian


    An experimental system has been set up to determine the coherence lengths of nonlinear optical crystals in the vacuum-ultraviolet (VUV) spectral region by measuring the Maker fringes in the VUV region. Using this system, the Maker fringes generated by frequency conversion from 354.7 to 177.3 nm in the BPO4 crystal were obtained and the coherence length corresponding to the nonlinear optical (NLO) coefficient d36 of the BPO4 crystal was determined to be lc(d36) = (0.785 ± 0.002) μm. To the best of our knowledge, this is the first time that the coherence length of NLO crystals in VUV was determined by experiment, and the result could be an essential parameter for designing a quasi-phase-matched BPO4 device.

  20. Luminescence of Ce3+ at two different sites in ?-Sr2P2O7 under vacuum ultraviolet-UV and x-ray excitation

    NARCIS (Netherlands)

    Hou, D.; Han, B.; Chen, W.; Liang, H.; Su, Q.; Dorenbos, P.; Huang, Y.; Gao, Z.; Tao, Y.


    A series of Ce3+ doped ?-Sr2?2xCexNaxP2O7 phosphor compounds has been prepared using a high-temperature solid-state reaction technique. The luminescence properties under vacuum ultraviolet-UV and x-ray excitation were studied. Luminescence spectra reveal three UV-emitting peaks at about 310, 330,

  1. Probing of Hermean Exosphere by ultraviolet spectroscopy: Instrument presentation, calibration philosophy and first lights results (United States)

    Mariscal, J. F.; Rouanet, N.; Maria, J. L.; Quémerais, E.; Mine, P. O.; Zuppella, P.; Suman, M.; Nicolosi, P.; Pelizzo, M. G.; Yoshikawa, I.; Yoshioka, K.; Murakami, G.


    PHEBUS (Probing of Hermean Exosphere by Ultraviolet Spectroscopy) is a double spectrometer for the Extreme Ultraviolet range (55-155 nm) and the Far Ultraviolet range (145-315 nm) dedicated to the characterization of Mercury's exosphere composition and dynamics, and surface-exosphere connections. PHEBUS is part of the ESA BepiColombo cornerstone mission payload devoted to the study of Mercury. The BepiColombo mission consists of two spacecrafts: the Mercury Magnetospheric Orbiter (MMO) and the Mercury Planetary Orbiter (MPO) on which PHEBUS will be mounted. PHEBUS is a French-led instrument implemented in a cooperative scheme involving Japan (detectors), Russia (scanner) and Italy (ground calibration). Before launch, PHEBUS team want to perform a full absolute calibration on ground, in addition to calibrations which will be made in-flight, in order to know the instrument's response as precisely as possible. Instrument overview and calibration philosophy are introduced along with the first lights results observed by a first prototype.

  2. Decontamination of unpackaged and vacuum-packaged boneless chicken breast with pulsed ultraviolet light. (United States)

    Keklik, N M; Demirci, A; Puri, V M


    The effectiveness of pulsed UV light on the microbial load of boneless chicken breast was investigated. Unpackaged and vacuum-packaged samples inoculated with an antibiotic-resistant strain of Salmonella Typhimurium on the top surfaces were treated with pulsed UV light for 5, 15, 30, 45, and 60 s at 5, 8, and 13 cm distance from the quartz window in the pulsed UV light chamber. The log(10) reductions of Salmonella (cfu/cm(2)) on unpackaged samples varied from 1.2 to 2.4 after a 5-s treatment at 13 cm and a 60-s treatment at 5 cm, respectively. The log(10) reductions on vacuum-packaged samples varied from 0.8 to 2.4 after the 5-s treatment at 13 cm and the 60-s treatment at 5 cm, respectively. The optimum treatment conditions were determined to be 5 cm-15 s for unpackaged samples and 5 cm-30 s for vacuum-packaged samples, both of which resulted in about 2 log(10) reduction (approximately 99%). The total energy and temperatures of samples increased with longer treatment time and shorter distance from the quartz window in the pulsed UV light chamber. The changes in chemical quality and color of samples were determined after mild (at 13 cm for 5 s), moderate (at 8 cm for 30 s), and extreme (at 5 cm for 60 s) treatments. Neither malonaldehyde contents nor color parameters changed significantly (P > 0.05) after mild and moderate treatments. Mechanical properties of the packaging material were analyzed before and after pulsed UV light treatments. The elastic modulus at both along-machine and perpendicular-to-machine direction and yield strength at perpendicular-to-machine direction changed significantly (P light has a potential to be used for decontamination of unpackaged and vacuum-packaged poultry.

  3. Low Damage Reductive Patterning of Oxidized Alkyl Self-Assembled Monolayers through Vacuum Ultraviolet Light Irradiation in an Evacuated Environment. (United States)

    Soliman, Ahmed I A; Tu, Yudi; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki


    Through 172 nm vacuum ultraviolet light irradiation in a high vacuum condition (HV-VUV), well-defined micropatterns with a varied periodic friction were fabricated at the surface of self-assembled monolayers (SAMs) terminated with oxygenated groups. No apparent height contrast between the HV-VUV-irradiated and -masked areas was observed, which indicated the stability of the C-C skeleton of the assembled molecules. The trimming of oxygenated groups occurred through dissociating the C-O bonds and promoting the occurrence of α- and β-cleavages in the C═O-containing components. Hence, the HV-VUV treatment trimmed the oxygenated groups without degrading the C-C skeleton. The HV-VUV treatment influenced the order of the assembled molecules, and the step-terrace structure was distorted. The decrease in friction at the HV-VUV-irradiated domains was attributed to the dissociation of oxygenated groups. (3-Aminopropyl)trimethoxysilane (APTMS) aggregated at the masked areas of the HV-VUV-patterned SAM, where the oxygenated groups worked as anchors. APTMS aggregations did not exist at the irradiated areas, indicating the trimming of the oxygenated groups at these areas. The direct assembling of APTMS on the Si substrate at the irradiated areas was prevented by the remaining C-C skeleton.

  4. Vacuum ultraviolet trimming of oxygenated functional groups from oxidized self-assembled hexadecyl monolayers in an evacuated environment (United States)

    Soliman, Ahmed I. A.; Utsunomiya, Toru; Ichii, Takashi; Sugimura, Hiroyuki


    Vacuum ultraviolet light irradiation in dry air generates active oxygen species, which have powerful oxidation abilities. These active oxygen species (O) can oxidize the alkyl moieties of polymers, and generate new oxygenated groups such as OH, CHO and COOH groups. Reducing the oxygen content in the exposure environment decreases the rate of oxidation processes. In this study, we examined the influences of the 172 nm VUV irradiation in a high vacuum (HV, < 10-3 Pa) environment on the chemical constituents, surface properties and morphological structure of well-defined VUV/(O)-modified hexadecyl (HD-) self-assembled monolayer (SAM) prepared on hydrogen-terminated silicon (H-Si) substrate. After VUV light irradiation in a HV environment (HV-VUV), the chemical constituents and surface properties were changed in two distinct stages. At short irradiation time (the first stage), the Csbnd O and COO groups decreased rapidly, while the Cdbnd O groups slightly changed. The dissociation of nonderivatizable groups (such as ether (Csbnd Osbnd C) and ester (Csbnd COOsbnd C) groups) compensated the dissociated OH, CHO, Csbnd COsbnd C and COOH groups. With further irradiation (the second stage), the quantities of the oxygenated groups slightly decreased. The carbon skeleton (Csbnd C) of SAM was scarcely dissociated during the HV-VUV treatment. These chemical changes affected the surface properties, such as wettability and morphology.

  5. Comparison of surface vacuum ultraviolet emissions with resonance level number densities. II. Rare-gas plasmas and Ar-molecular gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Boffard, John B., E-mail:; Lin, Chun C. [Department of Physics, University of Wisconsin, Madison, Wisconsin 53706 (United States); Wang, Shicong; Wendt, Amy E. [Department of Electrical and Computer Engineering, University of Wisconsin, Madison, Wisconsin 53706 (United States); Culver, Cody [Materials Science Program, University of Wisconsin, Madison, Wisconsin 53706 (United States); Radovanov, Svetlana; Persing, Harold [Applied Materials Inc., Gloucester, Massachusetts 01939 (United States)


    Vacuum ultraviolet (VUV) emissions from excited plasma species can play a variety of roles in processing plasmas, including damaging the surface properties of materials used in semiconductor processing. Depending on their wavelength, VUV photons can easily transmit thin upper dielectric layers and affect the electrical characteristics of the devices. Despite their importance, measuring VUV fluxes is complicated by the fact that few materials transmit at VUV wavelengths, and both detectors and windows are easily damaged by plasma exposure. The authors have previously reported on measuring VUV fluxes in pure argon plasmas by monitoring the concentrations of Ar(3p{sup 5}4s) resonance atoms that produce the VUV emissions using noninvasive optical emission spectroscopy in the visible/near-infrared wavelength range [Boffard et al., J. Vac. Sci. Technol., A 32, 021304 (2014)]. Here, the authors extend this technique to other rare-gases (Ne, Kr, and Xe) and argon-molecular gas plasmas (Ar/H{sub 2}, Ar/O{sub 2}, and Ar/N{sub 2}). Results of a model for VUV emissions that couples radiation trapping and the measured rare-gas resonance level densities are compared to measurements made with both a calibrated VUV photodiode and a sodium salicylate fluorescence detection scheme. In these more complicated gas mixtures, VUV emissions from a variety of sources beyond the principal resonance levels of the rare gases are found to contribute to the total VUV flux.

  6. Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region. (United States)

    Plogmaker, Stefan; Linusson, Per; Eland, John H D; Baker, Neville; Johansson, Erik M J; Rensmo, Håkan; Feifel, Raimund; Siegbahn, Hans


    A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of ~8 to ~120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

  7. Versatile high-repetition-rate phase-locked chopper system for fast timing experiments in the vacuum ultraviolet and x-ray spectral region

    Energy Technology Data Exchange (ETDEWEB)

    Plogmaker, Stefan; Johansson, Erik M. J.; Rensmo, Haakan; Feifel, Raimund; Siegbahn, Hans [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Linusson, Per [Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Eland, John H. D. [Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden); Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom); Baker, Neville [Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ (United Kingdom)


    A novel light chopper system for fast timing experiments in the vacuum-ultraviolet (VUV) and x-ray spectral region has been developed. It can be phase-locked and synchronized with a synchrotron radiation storage ring, accommodating repetition rates in the range of {approx}8 to {approx}120 kHz by choosing different sets of apertures and subharmonics of the ring frequency (MHz range). Also the opening time of the system can be varied from some nanoseconds to several microseconds to meet the needs of a broad range of applications. Adjusting these parameters, the device can be used either for the generation of single light pulses or pulse packages from a microwave driven, continuous He gas discharge lamp or from storage rings which are otherwise often considered as quasi-continuous light sources. This chopper can be utilized for many different kinds of experiments enabling, for example, unambiguous time-of-flight (TOF) multi-electron coincidence studies of atoms and molecules excited by a single light pulse as well as time-resolved visible laser pump x-ray probe electron spectroscopy of condensed matter in the valence and core level region.

  8. Evaluation of Sun Protection Factor of Zingiber officinale Roscoe Extract by Ultraviolet Spectroscopy Method


    Manoj A. Suva


    The purpose of present study was to evaluate the sun protection factor (SPF) of aqueous and methanolic extract of rhizomes of Zingiber officinale Roscoe by ultraviolet (UV) spectroscopy method. Aqueous and Methanolic extract of rhizomes of Zingiber officinale having concentration of 200µg/ml and 400µg/ml was prepared respectively and the SPF values were evaluated by UV spectroscopy. In this study, it was found that aqueous extract of Zingiber officinale (200µg/ml) have SPF value about 1.44±0....

  9. Ultraviolet resonance Raman spectroscopy for the detection of cocaine in oral fluid (United States)

    D'Elia, Valentina; Montalvo, Gemma; Ruiz, Carmen García; Ermolenkov, Vladimir V.; Ahmed, Yasmine; Lednev, Igor K.


    Detecting and quantifying cocaine in oral fluid is of significant importance for practical forensics. Up to date, mainly destructive methods or biochemical tests have been used, while spectroscopic methods were only applied to pretreated samples. In this work, the possibility of using resonance Raman spectroscopy to detect cocaine in oral fluid without pretreating samples was tested. It was found that ultraviolet resonance Raman spectroscopy with 239-nm excitation allows for the detection of cocaine in oral fluid at 10 μg/mL level. Further method development will be needed for reaching the practically useful levels of cocaine detection.

  10. SOLARNET & LAIME: Imaging & Spectroscopy in the Far Ultraviolet (United States)

    Damé, Luc; Koutchmy, Serge

    SOLARNET is a medium size high resolution solar physics mission proposed to CNES and ESA for a new start in 2007 and a possible launch in 2012 (CNES) or later (ESA Cosmic Vision framework: 2015-2016). Partnerships with India and China are under discussion, and several European contributions are considered. At the center of the SOLARNET mission is a 3-telescope interferometer of 1 meter baseline capable to provide 40 times the best ever spatial resolution achieved in Space with previous, current or even planned solar missions: 20 mas - 20 km on the Sun in the FUV. The interferometer is associated to an on-axis Subtractive Double Monochromator coupled to an Imaging Fourier Transform Spectrometer capable of high spectral (0.01 nm) and high temporal resolutions (50 ms) on a field of view of 40 arcsec and covering the FUV and UV spectral domains (from 117.5 to 400 nm). This will allow to access process scales of magnetic reconnection, dissipation, emerging flux and much more, from the chromosphere to the low corona with emphasis on the transition zone where the magnetic confinement is expected to be maximum. A whole new chapter of the physics of solar magnetic field structuring, evolution and mapping from the photosphere to the high atmosphere will be opened. The interferometer is completed by instruments providing larger field of view and higher temperature (EUV-XUV coronal imaging & spectroscopy) to define the context and extension of the solar phenomena. The 3-telescope interferometer design results of an extensive laboratory demonstration program of interferometric imaging of extended objects. We will review the scientific program of SOLARNET, describe the interferometer concept and design, present the results of the breadboard and give a short overview of the mission aspects. In a different category, LAIME, the Lyman Alpha Imaging-Monitor Experiment, is a remarkably simple (no mechanisms) and compact full Sun imager to be flown with TESIS on the CORONAS

  11. In situ X-ray photoelectron spectroscopy study of complex oxides under gas and vacuum environments (United States)

    Paloukis, F.; Papazisi, K. M.; Balomenou, S. P.; Tsiplakides, D.; Bournel, F.; Gallet, J.-J.; Zafeiratos, S.


    For several decades an open question in many X-ray photoelectron spectroscopy (XPS) studies was whether or not the results obtained in ultra-high vacuum conditions (UHV) were representative of the sample state in gas atmospheres. As a consequence, near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) was received by surface scientists as an important tool for in situ characterization of the gas-solid interactions. However, it is not yet clear how, if at all, the surface state formed in contact with the gas is modified when this gas is evacuated. In this work we compare synchrotron-based XPS results recorded at 300 °C on Ni/yttria- stabilized zirconia cermet and La0.75Sr0.25Cr0.9Fe0.1O3 perovskite, under 3.5 mbar O2 and UHV environments. We found that the surface state formed in O2 is maintained to a large extent under vacuum. In addition, we demonstrate that the correlation of XPS spectra recorded in the two conditions can provide information regarding the electrical conductivity of the specific surface sites of these complex oxides. Our findings suggest that comparison of XPS measurements in gas and in vacuum environments might be particularly useful in applications where the electronic conductivity at the surface plays a crucial role, as for example in solid oxide electrochemical devices.

  12. Vacuum ultraviolet radiation/atomic oxygen synergism in fluorinated ethylene propylene Teflon erosion (United States)

    Stiegman, A. E.; Brinza, David E.; Laue, Eric G.; Anderson, Mark S.; Liang, Ranty H.


    A micrographic investigation is reported of samples of the fluorinated ethylene propylene (FEP) Teflon thermal-blanketing materials recovered from the Long-Duration Exposure Facility (LDEF) satellite. The samples are taken from the trailing edge and row 8 which correspond to exposures to vacuum UV (VUV) and VUV + atomic O, respectively. Data are taken from SEM and IR-spectra observations, and the LDEF leading-edge FEP shows a high degree of erosion, roughening, and sharp peaks angled in the direction of the flow of atomic O. The trailing edge sample influenced primarily by VUV shows a hard brittle layer and some cracked mosaic patterns. Comparisons to a reference sample suggest that the brittle layer is related to exposure to VUV and is removed by atomic-O impingement. Polymers that are stable to VUV radiation appear to be more stable in terms of atomic oxygen.

  13. Optical absorption spectroscopy of metallic (Cr) vapor in a vacuum arc (United States)

    Wang, Haoran; Wang, Zhenxing; Liu, Jiankun; Zhou, Zhewei; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan


    The measurement of the metallic vapor density in a vacuum arc is crucial to acquire a better understanding of both the anodic activity and the dielectric recovery process in vacuum interrupters. The objective of this study was to measure the chromium vapor density and its axial distribution within the gap between the chromium contacts. Optical absorption spectroscopy (OAS) with a broadband light-source is adopted for this investigation. The results show that when the vacuum arc burns in the diffuse mode, the metallic vapor density maxima occur near the electrodes during the arcing period. At the peak current, the vapor density near the electrodes can be as high as 2.5  ×  1018 m‑3. With the decrease of the arc current, the metallic vapor density near the electrodes decreases as well, while the vapor density in the center of the gap remains nearly constant during the arcing period. At current zero, the metallic vapor in the gap has a nearly uniform distribution of about 3  ×  1017 m‑3. When the vacuum arc burns in the high-current mode, the metallic vapor density near the anode is lower than that in other areas until the vacuum arc becomes diffuse. Then, the evaporation process of the anodic molten region starts to play an important role and the metallic vapor density near the anode increases. At current zero, the metallic vapor has a density of about 4  ×  1018 m‑3 near the anode, which is much higher than anywhere else. Because the metallic vapor density at current zero is too low to cause a Townsend avalanche, extra factors are needed for initiating the breakdown in the post-arc phase. These factors could include a residual plasma within the gap and the behavior of the liquid metal in the molten anodic region.

  14. Mimicking Martian dust: An in-vacuum dust deposition system for testing the ultraviolet sensors on the Curiosity rover

    Energy Technology Data Exchange (ETDEWEB)

    Sobrado, J. M., E-mail:; Martín-Soler, J. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Martín-Gago, J. A. [Centro de Astrobiología (CAB), INTA-CSIC, Torrejón de Ardoz, 28850 Madrid (Spain); Instituto de Ciencias de Materiales de Madrid (ICMM–CSIC), Cantoblanco, 28049 Madrid (Spain)


    We have designed and developed an in-vacuum dust deposition system specifically conceived to simulate and study the effect of accumulation of Martian dust on the electronic instruments of scientific planetary exploration missions. We have used this device to characterize the dust effect on the UV sensor of the Rover Environmental Monitoring Station in the Mars science Laboratory mission of NASA in similar conditions to those found on Mars surface. The UV sensor includes six photodiodes for measuring the radiation in all UV wavelengths (direct incidence and reflected); it is placed on the body of Curiosity rover and it is severely affected by the dust deposited on it. Our experimental setup can help to estimate the duration of reliable reading of this instrument during operation. We have used an analogous of the Martian dust in chemical composition (magnetic species), color, and density, which has been characterized by X-ray spectroscopy. To ensure a Brownian motion of the dust during its fall and a homogeneous coverage on the instrumentation, the operating conditions of the vacuum vessel, determined by partial pressures and temperature, have to be modified to account for the different gravities of Mars with respect to Earth. We propose that our designed device and operational protocol can be of interest to test optoelectronic instrumentation affected by the opacity of dust, as can be the degradation of UV photodiodes in planetary exploration.

  15. Development of a high-speed vacuum ultraviolet (VUV) imaging system for the Experimental Advanced Superconducting Tokamak (United States)

    Zhou, Fan; Ming, Tingfeng; Wang, Yumin; Wang, Zhijun; Long, Feifei; Zhuang, Qing; Li, Guoqiang; Liang, Yunfeng; Gao, Xiang


    A high-speed vacuum ultraviolet (VUV) imaging system for edge plasma studies is being developed on the Experimental Advanced Superconducting Tokamak (EAST). Its key optics is composed of an inverse type of Schwarzschild telescope made of a set of Mo/Si multilayer mirrors, a micro-channel plate (MCP) equipped with a P47 phosphor screen and a high-speed camera with CMOS sensors. In order to remove the contribution from low-energy photons, a Zr filter is installed in front of the MCP detector. With this optics, VUV photons with a wavelength of 13.5 nm, which mainly come from the line emission from intrinsic carbon (C vi: n = 4-2 transition) or the Ly-α line emission from injected Li iii on the EAST, can be selectively measured two-dimensionally with both high temporal and spatial resolutions. At present, this system is installed to view the plasma from the low field side in a horizontal port in the EAST. It has been operated routinely during the 2016 EAST experiment campaign, and the first result is shown in this work. To roughly evaluate the system performance, synthetic images are created. And it indicates that this system mainly measures the edge localized emissions by comparing the synthetic images and experimental data.

  16. Ejecta Particle-Size Measurements in Vacuum and Helium Gas using Ultraviolet In-Line Fraunhofer Holography

    Energy Technology Data Exchange (ETDEWEB)

    Sorenson, D. S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pazuchanics, P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Malone, R. M. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Kaufman, M. I. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Tibbitts, A. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Tunnell, T. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Marks, D. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Capelle, G. A. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Grover, M. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Marshall, B. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Stevens, G. D. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Turley, W. D. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); LaLone, B. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States)


    An ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/μsec. This report will discuss the development of the diagnostic, including the high-powered laser system and high-resolution optical relay system. In addition, we will also describe the system required to reconstruct the images from the hologram and the corresponding analysis of those images to extract particles. Finally, we will present results from six high-explosive (HE), shock-driven Sn-ejecta experiments. Particle-size distributions will be shown that cover most of the ejecta velocities for experiments conducted in a vacuum, and helium gas environments. In addition, a modification has been made to the laser system that produces two laser pulses separated by 6.8 ns. This double-pulsed capability allows a superposition of two holograms to be acquired at two different times, thus allowing ejecta velocities to be measured directly. Results from this double-pulsed experiment will be described.

  17. Ejecta Particle-Size Measurements in Vacuum and Helium Gas using Ultraviolet In-Line Fraunhofer Holography

    Energy Technology Data Exchange (ETDEWEB)

    Sorenson, Danny S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pazuchanics, Peter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Randall P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Malone, R. M. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Kaufman, M. I. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Tibbitts, A. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Tunnell, T. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Marks, D. [National Security Technologies, LLC. (NSTec), Los Alamos, NM (United States); Capelle, G. A. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Grover, M. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Marshall, B. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Stevens, G. D. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); Turley, W. D. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States); LaLone, B. [National Security Technologies, LLC. (NSTec), Santa Barbara, CA (United States)


    An Ultraviolet (UV) in-line Fraunhofer holography diagnostic has been developed for making high-resolution spatial measurements of ejecta particles traveling at many mm/μsec. This report will discuss the development of the diagnostic including the high-powered laser system and high-resolution optical relay system. In addition, the system required to reconstruct the images from the hologram and the corresponding analysis of those images to extract particles will also be described. Finally, results from six high-explosive (HE), shock-driven Sn ejecta experiments will be presented. Particle size distributions will be shown that cover most of the ejecta velocities for experiments conducted in a vacuum, and helium gas environments. In addition, a modification has been made to the laser system that produces two laser pulses separated by 6.8 ns. This double-pulsed capability allows a superposition of two holograms to be acquired at two different times, thus allowing ejecta velocities to be measured directly. Results from this double pulsed experiment will be described.

  18. Experimental and theoretical studies of vacuum-ultraviolet electronic circular dichroism of hydroxy acids in aqueous solution. (United States)

    Fukuyama, Takayuki; Matsuo, Koichi; Gekko, Kunihiko


    The electronic circular dichroism (ECD) spectra of three L-hydroxy acids (L-lactic acid, (+)-(S)-2-hydroxy-3-methylbutyric acid, and (-)-(S)-2-hydroxyisocaproic acid) were measured down to 160 nm in aqueous solution using a vacuum-ultraviolet ECD spectrophotometer. To assign the two positive peaks around 210 and 175 nm and the one negative peak around 190 nm in the observed spectra, the ECD spectrum of L-lactic acid was calculated using time-dependent density functional theory (DFT) for the optimized structures by DFT and a continuum model. The observed ECD spectrum was successfully reproduced as the average spectrum for four optimized structures with seven water molecules that localized around the COO(-) and OH groups of L-lactic acid. The positive peak around 210 nm and the negative peak around 185 nm in the calculated spectrum were attributable to the nπ* transition of the carboxyl group, with the latter peak also being influenced by the ππ* transition of the carboxyl group; however, the positive peak around 165 nm involved unassignable higher energy transitions. The comparison of the calculated ECD spectra for L-lactic acid and L-alanine revealed that the network with loose hydrogen bonding around the COO(-) and OH groups is responsible for the flexible conformation of hydroxy acids and complicated side-chain dependence of ECD spectra relative to amino acids. Copyright © 2011 Wiley Periodicals, Inc.

  19. System for time resolved spectral studies of pulsed atmospheric discharges in the visible to vacuum ultraviolet range. (United States)

    Laity, G; Neuber, A; Rogers, G; Frank, K


    Vacuum ultraviolet (VUV) emission is believed to play a major role in the development of plasma streamers in pulsed atmospheric discharges, but detection of VUV light is difficult in pulsed experiments at atmospheric pressures. Since VUV light is absorbed in most standard optical materials as well, careful attention must be given to the selection of the lens and mirror optics used in these studies. Of highest interest is the VUV emission during the initial stage of pulsed atmospheric discharges, which has a typical duration in the nanosecond regime. An experiment was designed to study this fast initial stage of VUV emission coupled with fast optical imaging of streamer propagation, both with temporal resolution on the order of nanoseconds. A repetitive solid-state high voltage pulser was constructed which produces triggered flashover discharges with low jitter and consistent pulse amplitude. VUV emission is captured utilizing both photomultiplier and intensified charge-coupled device detectors during the fast stage of streamer propagation. These results are discussed in context with the streamer formation photographed in the visible wavelength regime with 3 ns exposure time.

  20. Vacuum ultra-violet damage and damage mitigation for plasma processing of highly porous organosilicate glass dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Marneffe, J.-F. de, E-mail:; Lukaszewicz, M.; Porter, S. B.; Vajda, F.; Rutigliani, V.; Verdonck, P.; Baklanov, M. R. [IMEC v.z.w., 3001 Leuven (Belgium); Zhang, L.; Heyne, M.; El Otell, Z.; Krishtab, M. [IMEC v.z.w., 3001 Leuven (Belgium); Department of Chemistry, KULeuven, 3001 Leuven (Belgium); Goodyear, A.; Cooke, M. [Oxford Instruments Plasma Technology, BS49 4AP Bristol (United Kingdom)


    Porous organosilicate glass thin films, with k-value 2.0, were exposed to 147 nm vacuum ultra-violet (VUV) photons emitted in a Xenon capacitive coupled plasma discharge. Strong methyl bond depletion was observed, concomitant with a significant increase of the bulk dielectric constant. This indicates that, besides reactive radical diffusion, photons emitted during plasma processing do impede dielectric properties and therefore need to be tackled appropriately during patterning and integration. The detrimental effect of VUV irradiation can be partly suppressed by stuffing the low-k porous matrix with proper sacrificial polymers showing high VUV absorption together with good thermal and VUV stability. In addition, the choice of an appropriate hard-mask, showing high VUV absorption, can minimize VUV damage. Particular processing conditions allow to minimize the fluence of photons to the substrate and lead to negligible VUV damage. For patterned structures, in order to reduce VUV damage in the bulk and on feature sidewalls, the combination of both pore stuffing/material densification and absorbing hard-mask is recommended, and/or the use of low VUV-emitting plasma discharge.

  1. Effects of pH on photochemical decomposition of perfluorooctanoic acid in different atmospheres by 185nm vacuum ultraviolet. (United States)

    Wang, Yuan; Zhang, Pengyi


    Perfluorooctanoic acid (PFOA), a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by 185nm vacuum ultraviolet (VUV) is one of the efficient methods for PFOA decomposition. The effects of pH on PFOA decomposition in nitrogen atmosphere or oxygen atmosphere were investigated. At its original pH (4.5) of PFOA aqueous solution, PFOA decomposed efficiently both in nitrogen and in oxygen atmosphere. However, when the pH increased to 12.0, PFOA decomposition was greatly inhibited in oxygen atmosphere, while it was greatly accelerated in nitrogen atmosphere with a very short half-life time (9min). Furthermore, fluorine atoms originally contained in PFOA molecules were almost completely transformed into fluoride ions. Two decomposition pathways have been proposed to explain the PFOA decomposition under different conditions. In acidic and neutral solutions, PFOA predominantly decomposes via the direct photolysis in both atmospheres; while in the alkaline solution and in the absence of oxygen, the decomposition of PFOA is mainly induced by hydrated electrons. Copyright © 2014. Published by Elsevier B.V.

  2. Real-time radiative divertor feedback control development for the NSTX-U tokamak using a vacuum ultraviolet spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V. A., E-mail: [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Kaita, R.; Stratton, B. [Princeton Plasma Physics Laboratory, 100 Stellarator Rd., Princeton, New Jersey 08543 (United States)


    A radiative divertor technique is planned for the NSTX-U tokamak to prevent excessive erosion and thermal damage of divertor plasma-facing components in H-mode plasma discharges with auxiliary heating up to 12 MW. In the radiative (partially detached) divertor, extrinsically seeded deuterium or impurity gases are used to increase plasma volumetric power and momentum losses. A real-time feedback control of the gas seeding rate is planned for discharges of up to 5 s duration. The outer divertor leg plasma electron temperature T{sub e} estimated spectroscopically in real time will be used as a control parameter. A vacuum ultraviolet spectrometer McPherson Model 251 with a fast charged-coupled device detector is developed for temperature monitoring between 5 and 30 eV, based on the Δn = 0, 1 line intensity ratios of carbon, nitrogen, or neon ion lines in the spectral range 300–1600 Å. A collisional-radiative model-based line intensity ratio will be used for relative calibration. A real-time T{sub e}-dependent signal within a characteristic divertor detachment equilibration time of ∼10–15 ms is expected.

  3. Real-time analysis of soot emissions from bituminous coal pyrolysis and combustion with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer. (United States)

    Gao, Shaokai; Zhang, Yang; Meng, Junwang; Shu, Jinian


    This paper reports on-line analyses of the soot emissions from the Inner Mongolia bituminous coal combustion and pyrolysis processes with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The soot particles are generated by heating a small amount of screened coal powder in synthetic air and nitrogen atmosphere in a tubular oven. The vacuum ultraviolet photoionization time-of-flight (VUV-TOF) mass spectra of the soot particles emitted from combustion and pyrolysis at different oven temperatures and different stages are obtained. The VUV-TOF mass spectra are assigned with the references of the results of the off-line GC/MS analysis.

  4. Preparation and characterization of pixelated phosphor screens for high-resolution linear imaging in the vacuum ultraviolet and x-ray ranges (United States)

    Rodríguez-Barquero, L.; Zurro, B.; Martin, P.; McCarthy, K. J.; Baciero, A.


    Indirect digital imaging sensors employ tailored phosphors screens to convert incident x-ray or vacuum-ultraviolet (VUV) photons to visible light quanta A convenient method to prepare pixelated phosphor screens that can be easily tailored in thickness, type, and spatial resolution is presented. The characterization and evaluation of these screens in the laboratory is addressed and their application to high-resolution VUV and x-ray cameras is discussed.

  5. Molecular beam mass spectrometry with tunable vacuum ultraviolet (VUV) synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Golan, Amir; Ahmed, Musahid


    Tunable soft ionization coupled to mass spectroscopy is a powerful method to investigate isolated molecules, complexes and clusters and their spectroscopy and dynamics.[1-4] Fundamental studies of photoionization processes of biomolecules provide information about electronic structure of these systems. Furthermore determinations of ionization energies and other properties of biomolecules in the gas phase are not trivial, and these experiments provide a platform to generate these data. We have developed a thermal vaporization technique coupled with supersonic molecular beams that provides a gentle way to transport these species into the gas phase. Judicious combination of source gas and temperature allows for formation of dimers and higher clusters of the DNA bases. The focus of this particular work is on the effects of non-covalent interactions, i.e., hydrogen bonding, stacking, and electrostatic interactions, on the ionization energies and proton transfer of individual biomolecules, their complexes and upon micro-hydration by water.[1, 5-9] We have performed experimental and theoretical characterization of the photoionization dynamics of gas-phase uracil and 1,3-methyluracil dimers using molecular beams coupled with synchrotron radiation at the Chemical Dynamics Beamline[10] located at the Advanced Light Source and the experimental details are visualized here. This allowed us to observe the proton transfer in 1,3-dimethyluracil dimers, a system with pi stacking geometry and with no hydrogen bonds[1]. Molecular beams provide a very convenient and efficient way to isolate the sample of interest from environmental perturbations which in return allows accurate comparison with electronic structure calculations[11, 12]. By tuning the photon energy from the synchrotron, a photoionization efficiency (PIE) curve can be plotted which informs us about the cationic electronic states. These values can then be compared to theoretical models and calculations and in turn, explain

  6. Continued Long-Term Ultraviolet Spectroscopy of a Tidal Disruption Event at only 90 Mpc (United States)

    Maksym, Walter


    We propose continued long-term multi-epoch ultraviolet spectroscopy of ASASSN-14li, a stellar tidal disruption event (TDE) at 90 Mpc. Such a bright, nearby stellar TDEs provides an exceptional opportunity to study broad emission lines which describe the abundances and accretion flow of the stellar debris in one of the most important physical regimes for understanding basic TDE behavior. We also request brief XMM observations to constrain the high-energy spectral evolution on similar timescales. These observations will build upon surprising new results, and will provide an important foundation for follow-up of more ambiguous TDE candidates subsequently identified by LSST and WFIRST at higher redshifts.


    Energy Technology Data Exchange (ETDEWEB)

    France, Kevin; Froning, Cynthia S. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Tian, Feng [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States); Roberge, Aki, E-mail: [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)


    Extrasolar planets orbiting M-stars may represent our best chance to discover habitable worlds in the coming decade. The ultraviolet spectrum incident upon both Earth-like and Jovian planets is critically important for proper modeling of their atmospheric heating and chemistry. In order to provide more realistic inputs for atmospheric models of planets orbiting low-mass stars, we present new near- and far-ultraviolet (NUV and FUV) spectroscopy of the M-dwarf exoplanet host GJ 876 (M4V). Using the COS and STIS spectrographs on board the Hubble Space Telescope, we have measured the 1150-3140 A spectrum of GJ 876. We have reconstructed the stellar H I Ly{alpha} emission line profile, and find that the integrated Ly{alpha} flux is roughly equal to the rest of the integrated flux (1150-1210 A + 1220-3140 A) in the entire ultraviolet bandpass (F(Ly{alpha})/F(FUV+NUV) Almost-Equal-To 0.7). This ratio is {approx}2500 Multiplication-Sign greater than the solar value. We describe the ultraviolet line spectrum and report surprisingly strong fluorescent emission from hot H{sub 2} (T(H{sub 2}) > 2000 K). We show the light curve of a chromospheric + transition region flare observed in several far-UV emission lines, with flare/quiescent flux ratios {>=}10. The strong FUV radiation field of an M-star (and specifically Ly{alpha}) is important for determining the abundance of O{sub 2}-and the formation of biomarkers-in the lower atmospheres of Earth-like planets in the habitable zones of low-mass stars.

  8. Time-Resolved Ultraviolet Spectroscopy of The M-Dwarf GJ 876 Exoplanetary System (United States)

    France, Kevin; Linsky, Jeffrey L.; Tian, Feng; Froning, Cynthia S.; Roberge, Aki


    Extrasolar planets orbiting M-stars may represent our best chance to discover habitable worlds in the coming decade. The ultraviolet spectrum incident upon both Earth-like and Jovian planets is critically important for proper modeling of their atmospheric heating and chemistry. In order to provide more realistic inputs for atmospheric models of planets orbiting low-mass stars, we present new near- and far-ultraviolet (NUV and FUV) spectroscopy of the M-dwarf exoplanet host GJ 876 (M4V). Using the COS and STIS spectrographs on board the Hubble Space Telescope, we have measured the 1150-3140 A spectrum of GJ 876. We have reconstructed the stellar H1 Ly alpha emission line profile, and find that the integrated Ly alpha flux is roughly equal to the rest of the integrated flux (1150-1210 A + 1220-3140 A) in the entire ultraviolet bandpass (F(Ly alpha)/F(FUV+NUV) equals approximately 0.7). This ratio is approximately 2500x greater than the solar value. We describe the ultraviolet line spectrum and report surprisingly strong fluorescent emission from hot H2 (T(H2) greater than 2000 K). We show the light curve of a chromospheric + transition region flare observed in several far-UV emission lines, with flare/quiescent flux ratios greater than or equal to 10. The strong FUV radiation field of an M-star (and specifically Ly alpha) is important for determining the abundance of O2--and the formation of biomarkers-in the lower atmospheres of Earth-like planets in the habitable zones of low-mass stars.

  9. Plasmon-assisted chemical reactions revealed by high-vacuum tip-enhanced Raman spectroscopy (United States)

    Lu, Shuaicheng; Sheng, Shaoxiang; Zhang, Zhenglong; Xu, Hongxing; Zheng, Hairong


    Tip-enhanced Raman spectroscopy (TERS) is the technique that combines the nanoscale spatial resolution of a scanning probe microscope and the highly sensitive Raman spectroscopy enhanced by the surface plasmons. It is suitable for chemical analysis at nanometer scale. Recently, TERS exhibited powerful potential in analyzing the chemical reactions at nanoscale. The high sensitivity and spatial resolution of TERS enable us to learn the reaction processes more clearly. More importantly, the chemical reaction in TERS is assisted by surface plasmons, which provides us an optical method to manipulate the chemical reactions at nanoscale. Here using our home-built high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) setup, we successfully observed the plasmon-assisted molecule dimerization and dissociation reactions. In HV-TERS system, under laser illumination, 4-nitrobenzenethiol (4NBT) molecules can be dimerized to p,p'-dimercaptoazobenzene (DMAB), and dissociation reaction occurs for malachite green (MG) molecules. Using our HV-TERS setup, the dynamic processes of the reactions are clearly revealed. The chemical reactions can be manipulated by controlling the plasmon intensity through changing the power of the incident laser, the tunneling current and the bias voltage. We also investigated the role of plasmonic thermal effect in the reactions by measuring both the Stokes and anti- Stokes Raman peaks. Our findings extend the applications of TERS, which can help to study the chemical reactions and understand the dynamic processes at single molecular level, and even design molecules by the plasmon-assisted chemical reactions.

  10. Using laser-induced breakdown spectroscopy on vacuum alloys-production process for elements concentration analysis (United States)

    Zhao, Tianzhuo; Fan, Zhongwei; Lian, Fuqiang; Liu, Yang; Lin, Weiran; Mo, Zeqiang; Nie, Shuzhen; Wang, Pu; Xiao, Hong; Li, Xin; Zhong, Qixiu; Zhang, Hongbo


    Laser-induced breakdown spectroscopy (LIBS) utilizing an echelle spectrograph-ICCD system is employed for on-line analysis of elements concentration in a vacuum induction melting workshop. Active temperature stabilization of echelle spectrometer is implemented specially for industrial environment applications. The measurement precision is further improved by monitoring laser parameters, such as pulse energy, spatial and temporal profiles, in real time, and post-selecting laser pulses with specific pulse energies. Experimental results show that major components of nickel-based alloys are stable, and can be well detected. By using internal standard method, calibration curves for chromium and aluminum are obtained for quantitative determination, with determination coefficient (relative standard deviation) to be 0.9559 (< 2.2%) and 0.9723 (< 2.8%), respectively.

  11. Secondary structure prediction of protein constructs using random incremental truncation and vacuum-ultraviolet CD spectroscopy

    CERN Document Server

    Pukáncsik, M; Matsuo, K; Gekko, K; Hart, D; Kézsmárki, I; Vértessy, B G


    A novel uracil-DNA degrading protein factor (termed UDE) was identified in Drosophila melanogaster with no significant structural and functional homology to other uracil-DNA binding or processing factors. Determination of the 3D structure of UDE will be a true breakthrough in description of the molecular mechanism of action of UDE catalysis, as well as in general uracil-recognition and nuclease action. The revolutionary ESPRIT technology was applied to the novel protein UDE to overcome problems in identifying soluble expressing constructs given the absence of precise information on domain content and arrangement. Nine specimen from the created numerous truncated constructs of UDE were choosen to dechiper structural and functional relationships. VUVCD with neural network was performed to define the secondary structure content and location of UDE and its truncated variants. The quantitative analysis demonstrated exclusive {\\alpha}-helical content for the full-length protein, which is preserved in the truncated ...

  12. Spectral Behavior of White Pigment Mixtures Using Reflectance, Ultraviolet-Fluorescence Spectroscopy, and Multispectral Imaging. (United States)

    Pronti, Lucilla; Felici, Anna Candida; Ménager, Matthieu; Vieillescazes, Cathy; Piacentini, Mario


    Reflectance spectroscopy, ultraviolet (UV)-fluorescence spectroscopy, and multispectral imaging have been widely employed for pigment identification on paintings. From ancient times to the present, lead white, zinc white, and titanium white have been the most important white pigments used for paintings and they are used as pigment markers for dating a work of art. The spectral behavior of these pigments is reported in several scientific papers and websites, but those of their mixtures are quite unknown. We present a combined nondestructive approach for identifying mixtures of lead white, zinc white, and titanium white as powder and dispersed in two different binder media (egg yolk and linseed oil) by using reflectance spectroscopy, spectrofluorimetry, multispectral reflectance and UV-fluorescence imaging. We propose a novel approach for mapping the presence of white pigments in paintings by false color images obtained from multispectral reflectance and UV-fluorescence images. We found that the presence of lead white mixed with either zinc white or titanium white is highly detectable. Zinc white mixed with lead white or titanium white can be identified due to its UV-fluorescence emission, whereas titanium white in association with lead white or zinc white is distinguishable by its reflectance spectral features. In most cases, the UV-fluorescence analyses also permit the recognition of the binder media in which the pigments are dispersed.

  13. Extreme ultraviolet spectroscopy and atomic models of highly charged heavy ions in the Large Helical Device (United States)

    Suzuki, C.; Murakami, I.; Koike, F.; Tamura, N.; Sakaue, H. A.; Morita, S.; Goto, M.; Kato, D.; Ohashi, H.; Higashiguchi, T.; Sudo, S.; O'Sullivan, G.


    We report recent results of extreme ultraviolet (EUV) spectroscopy of highly charged heavy ions in plasmas produced in the Large Helical Device (LHD). The LHD is an ideal source of experimental databases of EUV spectra because of high brightness and low opacity, combined with the availability of pellet injection systems and reliable diagnostic tools. The measured heavy elements include tungsten, tin, lanthanides and bismuth, which are motivated by ITER as well as a variety of plasma applications such as EUV lithography and biological microscopy. The observed spectral features drastically change between quasicontinuum and discrete depending on the plasma temperature, which leads to some new experimental identifications of spectral lines. We have developed collisional-radiative models for some of these ions based on the measurements. The atomic number dependence of the spectral feature is also discussed.

  14. Vacuum UV spectroscopy of armor erosion from plasma gun disruption simulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rockett, P.D. [Sandia Nat. Labs., Albuquerque, NM (United States). Fusion Tech. Dept.; Hunter, J.A. [Sandia Nat. Labs., Albuquerque, NM (United States). Fusion Tech. Dept.; Bradley, J.T. III [Electrical Engineering and Computer Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States); Gahl, J.M. [Electrical Engineering and Computer Engineering Department, University of New Mexico, Albuquerque, NM 87131 (United States); Zhitlukhin, A. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Region (Russian Federation); Arkhipov, K. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Region (Russian Federation); Bakhtin, V. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Region (Russian Federation); Toporkov, D. [Troitsk Institute for Innovation and Technology (TRINITI), Troitsk, Moscow Region (Russian Federation); Ovchinnokov, I. [Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Kuznetsov, V.E. [Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Titov, V.A. [Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation)


    Extensive simulations of tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense vapor shield. Two transmission grating vacuum ultraviolet (VUV) spectrographs were designed and utilized to study the plasma-material interface in plasma gun simulation experiments. Target materials included POCO graphite, ATJ graphite, boron nitride and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of ca. 0.7mm resolution on VIKA at Efremov and on 2MK-200 at Troitsk. Time-resolved data with 40-200ns resolution were then recorded along with the same spatial resolution on 2MK-200. The VIKA plasma gun directly illuminated a target with a high-intensity plasma pulse of 2-100MJm{sup -2} with low-energy ions of ca. 100eV. The 2MK-200 plasma gun illuminated the target via a magnetic cusp that permitted only deuterium to pass with energies of ca. 1keV, but which produced a fairly low intensity of 2MJm{sup -2}. Power densities on target ranged from 10{sup 7} to 10{sup 8}Wcm{sup -2}. Emitted spectra were recorded from 15 to 450A over a distance from 0 to 7cm above the armor target surface. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface. This apparently constituted the absorption region, which confirmed past computer simulations. Spectra indicated both the species and ionization level that were being ablated from the target, demonstrating impurity content, and showing plasma ablation velocity. Graphite samples clearly showed CV lines as well as impurity lines from O V and O VI. The BN tiles produced textbook examples of BIV and BV, and extensive NIV, V and VI lines. These are being compared with radiation-hydrodynamic calculations. (orig.).

  15. Ultraviolet reflectance spectroscopy measurements of carbonaceous meteorites and planetary analog materials (United States)

    Hibbitts, Charles A.; Stockstill-Cahill, Karen; Takir, Driss


    The compositions of airless solar system objects tell us about the origin and evolutionary processes that are responsible for the current state of our solar system and that shape our environment. Spectral reflectance measurements in the ultraviolet are being used more frequently for providing compositional information of airless solid surfaces. Most minerals absorb in the UV making studying surface composition both informative but also challenging [e.g. 1]. The UV region is sensitive to atomic and molecular electronic absorptions such as the ligand-metal charge transfer band that is present in oxides and silicates and the conduction band at vacuum UV wavelengths. At the JHU-APL, bidirectional UV reflectance measurements are obtained under vacuum using a McPherson monochrometer with a PMT detector to achieve measurements over the range from ~ 140 nm to ~ 570 nm. Sample temperature can also be controlled from ~ 100K to ~ 600K, which enables the exploring the interaction of water ice and other volatiles with refractory samples. We have measured the UV spectra of many carbonaceous chondrites, including Mokoia, Vigarano, Warrenton, Orgueil, SaU290, and Essebi. In addition to being dark, some also possess on OMCT band. We have also obtained IR measurement of these meteorites to explore possible correlations between their UV and IR spectral signatures. In addition, we have also measured the UV spectra of low water content lunar analog glasses and have found a correlation between the spectral nature of the OMCT band and the abundance of iron [3]. Also, the spectral signature of mineralic and adsorbed water in the UV has been investigated. While water-ice has a known strong absorption feature near 180 nm (e.g. 4], adsorbed molecular and disassociatively adsorbed OH appear to not be optically active in this spectral region [5]. References: [1] Wagner et al. (1987) Icarus, 69, 14-28.1987; [2] Cloutis et al. (2008) Icarus, 197, 321-347; [3] Greenspon et al. (2012), 43rd LPSC

  16. Explosive Events in the Quiet Sun: Extreme Ultraviolet Imaging Spectroscopy Instrumentation and Observations (United States)

    Rust, Thomas Ludwell

    Explosive event is the name given to slit spectrograph observations of high spectroscopic velocities in solar transition region spectral lines. Explosive events show much variety that cannot yet be explained by a single theory. It is commonly believed that explosive events are powered by magnetic reconnection. The evolution of the line core appears to be an important indicator of which particular reconnection process is at work. The Multi-Order Solar Extreme Ultraviolet Spectrograph (MOSES) is a novel slitless spectrograph designed for imaging spectroscopy of solar extreme ultraviolet (EUV) spectral lines. The spectrograph design forgoes a slit and images instead at three spectral orders of a concave grating. The images are formed simultaneously so the resulting spatial and spectral information is co-temporal over the 20' x 10' instrument field of view. This is an advantage over slit spectrographs which build a field of view one narrow slit at a time. The cost of co-temporal imaging spectroscopy with the MOSES is increased data complexity relative to slit spectrograph data. The MOSES data must undergo tomographic inversion for recovery of line profiles. I use the unique data from the MOSES to study transition region explosive events in the He ii 304 A spectral line. I identify 41 examples of explosive events which include 5 blue shifted jets, 2 red shifted jets, and 10 bi-directional jets. Typical doppler speeds are approximately 100kms-1. I show the early development of one blue jet and one bi-directional jet and find no acceleration phase at the onset of the event. The bi-directional jets are interesting because they are predicted in models of Petschek reconnection in the transition region. I develop an inversion algorithm for the MOSES data and test it on synthetic observations of a bi-directional jet. The inversion is based on a multiplicative algebraic reconstruction technique (MART). The inversion successfully reproduces synthetic line profiles. I then use

  17. Spectroscopy of Highly Charged Tin Ions for AN Extreme Ultraviolet Light Source for Lithography (United States)

    Torretti, Francesco; Windberger, Alexander; Ubachs, Wim; Hoekstra, Ronnie; Versolato, Oscar; Ryabtsev, Alexander; Borschevsky, Anastasia; Berengut, Julian; Crespo Lopez-Urrutia, Jose


    Laser-produced tin plasmas are the prime candidates for the generation of extreme ultraviolet (EUV) light around 13.5 nm in nanolithographic applications. This light is generated primarily by atomic transitions in highly charged tin ions: Sn^{8+}-Sn^{14+}. Due to the electronic configurations of these charge states, thousands of atomic lines emit around 13.5 nm, clustered in a so-called unresolved transition array. As a result, accurate line identification becomes difficult in this regime. Nevertheless, this issue can be circumvented if one turns to the optical: with far fewer atomic states, only tens of transitions take place and the spectra can be resolved with far more ease. We have investigated optical emission lines in an electron-beam-ion-trap (EBIT), where we managed to charge-state resolve the spectra. Based on this technique and on a number of different ab initio techniques for calculating the level structure, the optical spectra could be assigned [1,2]. As a conclusion the assignments of EUV transitions in the literature require corrections. The EUV and optical spectra are measured simultaneously in the controlled conditions of the EBIT as well as in a droplet-based laser-produced plasma source providing information on the contribution of Sn^{q+} charge states to the EUV emission. [1] A. Windberger, F. Torretti, A. Borschevsky, A. Ryabtsev, S. Dobrodey, H. Bekker, E. Eliav, U. Kaldor, W. Ubachs, R. Hoekstra, J.R. Crespo Lopez-Urrutia, O.O. Versolato, Analysis of the fine structure of Sn^{11+} - Sn^{14+} ions by optical spectroscopy in an electron beam ion trap, Phys. Rev. A 94, 012506 (2016). [2] F. Torretti, A. Windberger, A. Ryabtsev, S. Dobrodey, H. Bekker, W. Ubachs, R. Hoekstra, E.V. Kahl, J.C. Berengut, J.R. Crespo Lopez-Urrutia, O.O. Versolato, Optical spectroscopy of complex open 4d-shell ions Sn^{7+} - Sn^{10+}, arXiv:1612.00747

  18. Detection of Be+sdO Evolved Binaries from Ultraviolet Spectroscopy (United States)

    Gies, Douglas; Wang, Luqian; Peters, Geraldine


    Be stars are rapidly rotating, non-supergiant B-type stars that eject equatorial disks. Many of these stars may have been spun up through mass transfer in a close binary system, in which case the former mass donor star is now a hot, stripped-down, subdwarf. There are five known cases of Be stars with hot subdwarf (sdO) companions that were discovered through International Ultraviolet Explorer (IUE) spectroscopy. Here we expand the search for Be+sdO candidates using archival FUV spectra from IUE. Our search strategy involves calculation of a cross-correlation funtion (CCF) of each observed spectrum with a model spectrum for T_eff = 45 kK, the typical value for the known subdwarf companions. We collected IUE spectra for 264 targets, and selected for closer examination those with a CCF peak greater than three times the background CCF noise. We applied two selection criteria to select candidate Be+sdO binaries: targets showing a significant and narrow CCF feature (with a half-width much smaller than the projected rotational velocity of the Be star) and also displayed radial velocity shifts indicative of orbital motion. We identified eight candidate systems that met both criteria plus four other candidate systems with strong peaks but too few spectra to confirm orbital motion. These are important targets for follow up spectroscopy. The new plus known Be+sdO binaries comprise about 6% of the sample. This fraction is consistent with the idea that we only find sdO companions in their relatively short and bright evolutionary stage of He-shell burning, while the majority of He-core burning companions are too faint to detect with current methods.

  19. Optimal Wavelength Selection in Ultraviolet Spectroscopy for the Estimation of Toxin Reduction Ratio during Hemodialysis

    Directory of Open Access Journals (Sweden)

    Amir Ghanifar


    Full Text Available Introduction The concentration of substances, including urea, creatinine, and uric acid, can be used as an index to measure toxic uremic solutes in the blood during dialysis and interdialytic intervals. The on-line monitoring of toxin concentration allows for the clearance measurement of some low-molecular-weight solutes at any time during hemodialysis.The aim of this study was to determine the optimal wavelength for estimating the changes in urea, creatinine, and uric acid in dialysate, using ultraviolet (UV spectroscopy. Materials and Methods In this study, nine uremic patients were investigated, using on-line spectrophotometry. The on-line absorption measurements (UV radiation were performed with a spectrophotometer module, connected to the fluid outlet of the dialysis machine. Dialysate samples were obtained and analyzed, using standard biochemical methods. Optimal wavelengths for both creatinine and uric acid were selected by using a combination of genetic algorithms (GAs, i.e., GA-partial least squares (GA-PLS and interval partial least squares (iPLS. Results The Artifitial Neural Network (ANN sensitivity analysis determined the wavelengths of the UV band most suitable for estimating the concentration of creatinine and uric acid. The two optimal wavelengths were 242 and 252 nm for creatinine and 295 and 298 nm for uric acid. Conclusion It can be concluded that the reduction ratio of creatinine and uric acid (dialysis efficiency could be continuously monitored during hemodialysis by UV spectroscopy.Compared to the conventional method, which is particularly sensitive to the sampling technique and involves post-dialysis blood sampling, iterative measurements throughout the dialysis session can yield more reliable data.

  20. The Normal-incidence Vacuum-ultraviolet Spectrometer for the TJ-II and First Experimental Results

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, K.J.; Zurro, B.; Baciero, A.


    A normal-incidence spectrometer, operating in the extreme-ultraviolet and ultraviolet wavelength regions, has been commissioned for the TJ-II stellarator. The instrument has been custom built by McPherson, Chelmsford, MA, and has several unique features and accessories that are described here. The instrument and CCD detector has been tested and calibrated, and its performance evaluated, using spectral lines from glow discharges and a RF excited flow lamp. Finally, the first spectra collected with the instrument of TJ-II plasmas are presented and a preliminary estimation of an oxygen ion temperature is made. (Author) 23 refs.

  1. Study of hemoglobin response to mid-ultraviolet (UVB) radiation using micro-Raman spectroscopy (United States)

    Huang, Y. Y.; Li, N.; Zhou, S. N.; Huang, Z. T.; Zhuang, Z. F.


    Confocal micro-Raman spectroscopy is employed to monitor the damage to haemoglobin from mid-ultraviolet (UVB) radiation. We obtained the Raman spectra of an erythrocyte, which indicated that a peroxidation reaction occurs after UVB radiation. Further, the surface enhanced Raman scattering (SERS) spectra of isolated haemoglobin show that the intensities of the 1375 and 1399 cm-1 bands, which are markers of haem aggregation, obviously increase with prolonged UVB irradiation. This increase reveals that haem aggregation occurs in the peroxidation of erythrocytes. The UV-Vis spectra of isolated haemoglobin indicate that the Soret band, which is indicative of excitonic interactions in the aggregated haems, has a redshift ( 12 nm) after 30 min of UVB irradiation of erythrocytes. It can be deduced that an excitonic interaction occurs in the aggregated haems, which is caused by haemoglobin denaturation following UVB irradiation. In addition, the changes of the Raman marker bands during aggregation primarily originate from excitonic interactions. Throughout the process, a higher UVB radiation dose causes greater damage to haemoglobin.

  2. Resonance Effects in the Ultraviolet Raman Spectroscopy of Collagen in Mineralized Tissues (United States)

    Ager, J. W., III; Pugach, M.; Habelitz, S.; Balooch, G.; Kinney, J. H.; Marshall, G. W.; Ritchie, R. O.


    Ultraviolet resonance Raman spectroscopy (UVRRS) was used to investigate type I collagen in solid tissues including tendon, dentin, and bone. With 244 nm excitation, spectral features from both the amide backbone (amide I, II, and III) and resonance-enhanced side-chain vibrations (Y8a, tyrosine) were observed. This contrasts with reported Raman spectra of proteins in solution excited with similar UV wavelengths, where side chain vibrations, but not strong amide features, are observed. The height of the dominant amide I feature in teeth and bone can be reversibly increased/decreased in dentin by dehydration/rehydration cycles. Also, the amide I peak is relatively stronger in both human bone and dentin from older donors. The strong intensity of the amide I UVRRS feature in these mineralized tissues is attributed to an increase in the width of the π-> π^* amide resonance in collagen compared to the solution phase. These findings suggest that UVRRS can be used as a specific probe of the collagen environment in bone and dentin.

  3. Sum-Frequency-Generation-Based Laser Sidebands for Tunable Femtosecond Raman Spectroscopy in the Ultraviolet

    Directory of Open Access Journals (Sweden)

    Liangdong Zhu


    Full Text Available Femtosecond stimulated Raman spectroscopy (FSRS is an emerging molecular structural dynamics technique for functional materials characterization typically in the visible to near-IR range. To expand its applications we have developed a versatile FSRS setup in the ultraviolet region. We use the combination of a narrowband, ~400 nm Raman pump from a home-built second harmonic bandwidth compressor and a tunable broadband probe pulse from sum-frequency-generation-based cascaded four-wave mixing (SFG-CFWM laser sidebands in a thin BBO crystal. The ground state Raman spectrum of a laser dye Quinolon 390 in methanol that strongly absorbs at ~355 nm is systematically studied as a standard sample to provide previously unavailable spectroscopic characterization in the vibrational domain. Both the Stokes and anti-Stokes Raman spectra can be collected by selecting different orders of SFG-CFWM sidebands as the probe pulse. The stimulated Raman gain with the 402 nm Raman pump is >21 times larger than that with the 550 nm Raman pump when measured at the 1317 cm−1 peak for the aromatic ring deformation and ring-H rocking mode of the dye molecule, demonstrating that pre-resonance enhancement is effectively achieved in the unique UV-FSRS setup. This added tunability in the versatile and compact optical setup enables FSRS to better capture transient conformational snapshots of photosensitive molecules that absorb in the UV range.

  4. The NASA probe-class mission concept, CETUS (Cosmic Evolution Through Ultraviolet Spectroscopy) (United States)

    Heap, Sara; Danchi, William; Burge, James; Dodson, Kelly; Hull, Anthony; Kendrick, Steven; McCandliss, Stephan; Mehle, Gregory; Purves, Lloyd; Sheikh, David; Valente, Martin; Woodruff, Robert A.


    We report on the early phases of a NASA-sponsored study of CETUS (Cosmic Evolution Through Ultraviolet Spectroscopy), a Probe-class mission concept. By definition, the full lifecycle cost of a Probe mission is greater than 400M (i.e. Explorer missions) and less than 1.00B ("Flagship" missions). The animating idea behind our study is that CETUS can help answer fundamental questions about galaxy evolution by carrying out a massive UV imaging and spectroscopic survey of galaxies and combining its findings with data obtained by other survey telescopes of the 2020's. The CETUS mission concept comprises a 1.5-m wide-field telescope and three scientific instruments: a near-UV multi-object slit spectrograph with a micro-shutter array as the slit device; a near-UV and far-UV camera with angular resolution of 0.42" (near-UV) or 0.55" (far-UV); and a near-UV or far-UV single-object spectrograph aimed at providing access to the UV after Hubble is gone. We describe the scientific rationale for CETUS and the telescope and instruments in their early design phase.

  5. 3m Vacuum Ultraviolet Spectrometer with Optical Multichannel Detector; Espectrometro de ultravioleta de vacio de 3m provisto de sistema de deteccion optical multicanal

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P.; Peraza, C.; Blanco, F.; Campos, J.


    This paper describes the design and the performance of a normal incidence vacuum ultraviolet spectrometer, for the 300-2400 A spectral range. It is provided with a multichannel detection system. The monochromator is original design and it has been built at CIEMAT. It is equipped with a 3 m concave holographic grating with 2400 grooves/mm. The multichannel detector consists of a windowless double microchannel plate / phosphor screen image intensifier, coupled by fiber optic to a 1024 elements self-scanning linear photodiode array. The output from the array is digitized by a 12-bit analog to digital converter and stored in a computer, for its later analysis. The necessary software to store and display data has been developed. (Author) 18 refs.

  6. Supercontinuum generation and tunable ultrafast emission in the vacuum ultraviolet using noble-gas-filled hollow-core photonic crystal fiber

    CERN Document Server

    Ermolov, Alexey; Frosz, Michael H; Travers, John C; Russell, Philip St J


    We report on the generation of a three-octave supercontinuum extending from the vacuum ultraviolet (VUV) to the near-infrared, spanning at least 113 to 1000 nm (i.e., 11 to 1.2 eV), in He-filled hollow-core kagome-style photonic crystal fiber. The same system also permits generation of narrower-band VUV radiation tunable from 113 to 200 nm with efficiencies exceeding 1% and VUV pulse energies in excess of 50 nJ. Modeling confirms that the mechanism involves soliton self-compression to sub-femtosecond pulse durations, dispersive-wave emission and the plasma-induced soliton self-frequency blue-shift. The bandwidth of the generated VUV light, which modeling shows to be coherent, is sufficient to support 500 as single-cycle pulses.

  7. Synergistic Formation of Radicals by Irradiation with Both Vacuum Ultraviolet and Atomic Hydrogen: A Real-Time In Situ Electron Spin Resonance Study

    CERN Document Server

    Ishikawa, Kenji; Kono, Akihiko; Horibe, Hideo; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru; 10.1021/jz2002937


    We report on the surface modification of polytetrafluoroethylene (PTFE) as an example of soft- and bio-materials that occur under plasma discharge by kinetics analysis of radical formation using in situ real-time electron spin resonance (ESR) measurements. During irradiation with hydrogen plasma, simultaneous measurements of the gas-phase ESR signals of atomic hydrogen and the carbon dangling bond (C-DB) on PTFE were performed. Dynamic changes of the C-DB density were observed in real time, where the rate of density change was accelerated during initial irradiation and then became constant over time. It is noteworthy that C-DBs were formed synergistically by irradiation with both vacuum ultraviolet (VUV) and atomic hydrogen. The in situ real-time ESR technique is useful to elucidate synergistic roles during plasma surface modification.

  8. Vacuum ultraviolet spectroscopic properties of rare earth (RE=Ce,Tb,Eu,Tm,Sm)-doped hexagonal KCaGd(PO4)2 phosphate (United States)

    Zhang, Z. J.; Yuan, J. L.; Duan, C. J.; Xiong, D. B.; Chen, H. H.; Zhao, J. T.; Zhang, G. B.; Shi, C. S.


    Hexagonal KCaGd(PO4)2:RE3+ (RE =Ce,Tb,Eu,Tm,Sm) were synthesized by coprecipitation method and their vacuum ultraviolet-ultraviolet (VUV-UV) spectroscopic properties were investigated. The bands at about 165nm in the VUV excitation spectra are attributed to the host lattice absorptions. For Ce3+-doped samples, the bands at 207, 256, 275, and 320nm are assigned to the 4f-5d transitions of Ce3+ in KCaGd(PO4)2. For Tb3+-doped sample, the bands at 203 and 222nm are related to the 4f-5d spin-allowed transitions. For Eu3+-doped sample, the O2--Eu3+ charge-transfer band (CTB) at 229nm is observed, and the fine emission spectrum of Eu3+ indicates that Eu3+ ions prefer to occupy Gd3+ or Ca2+ sites in the host lattice. For Tm3+- and Sm3+-doped samples, the O2--Tm3+ and O2--Sm3+ CTBs are observed to be at 176 and 186nm, respectively. From the standpoints of the absorption band, color purity, and luminescent intensity, Tb3+-doped KCaGd(PO4)2 is a potential candidate for 172nm excited green plasma display phosphors.

  9. Extreme ultraviolet fluorescence spectroscopy of pure and core-shell rare gas clusters at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Schroedter, Lasse


    The interaction of rare gas clusters with short-wavelength radiation of free-electron lasers (FELs) has been studied extensively over the last decade by means of electron and ion time-of-flight spectroscopy. This thesis describes the design and construction of a fluorescence spectrometer for the extreme ultraviolet (XUV) spectral range and discusses the cluster experiments performed at FLASH, the Free-electron LAser in Hamburg. Fluorescence of xenon and of argon clusters was studied, both in dependence on the FEL pulse intensity and on the cluster size. The FEL wavelength was set to the giant 4d-resonance of xenon at 13.5 nm and the FEL pulse intensity reached peak values of 2.7.10{sup 15} W/cm{sup 2}. For xenon clusters, charge states of at least 11+ were identified. For argon, charge states up to 7+ were detected. The cluster-size dependent study revealed a decrease of the fluorescence yield per atom with increasing cluster size. This decrease is explained with the help of a geometric model. It assumes that virtually the entire fluorescence yield stems from shells of ions on the cluster surface, whereas ions in the cluster core predominantly recombine non-radiatively with electrons. However, the detailed analysis of fluorescence spectra from clusters consisting of a core of Xe atoms and a surrounding shell of argon atoms shows that, in fact, a small fraction of the fluorescence signal comes from Xe ions in the cluster core. Interestingly, these ions are as highly charged as the ions in the shells of a pure Xe cluster. This result goes beyond the current understanding of charge and energy transfer processes in these systems and points toward the observation of ultrafast charging dynamics in a time window where mass spectrometry is inherently blind. (orig.)

  10. Effects of Exposure to Physical Factors on Homeopathic Preparations as Determined by Ultraviolet Light Spectroscopy

    Directory of Open Access Journals (Sweden)

    Barbara Marschollek


    Full Text Available Clinical trials have reported statistically significant and clinically relevant effects of homeopathic preparations. We applied ultraviolet (UV spectroscopy to investigate the physical properties of homeopathic preparations and to contribute to an understanding of the not-yet-identified mode of action. In previous investigations, homeopathic preparations had significantly lower UV light transmissions than controls. The aim of this study was to explore the possible effects of external factors (UV light and temperature on the homeopathic preparations. Homeopathic centesimal (c dilutions, 1c to 30c, of copper sulfate (CuSO4, decimal dilutions of sulfur (S8, 1x to 30x, and controls (succussed potentization medium were prepared, randomized, and blinded. UV transmission was measured at six different time points after preparation (from 4 to 256 days. In addition, one series of samples was exposed to UV light of a sterilization lamp for 12 h, one was incubated at 37°C for 24 h, and one was heated to 90°C for 15 min. UV light transmission values from 190 or 220 nm to 340 nm were measured several times and averaged. After each exposure, UV transmission of the homeopathic preparations of CuSO4 was significantly reduced compared to the controls, particularly after heating to 37°C. Overall, the nonexposed CuSO4 preparations did not show significantly lower UV transmission compared to controls; however, the pooled subgroup of measurements at days 26, 33, and 110 yielded significant differences. UV light transmission for S8 preparations did not show any differences compared to controls. Our conclusion is that exposure to external factors, incubation at 37°C in particular, increases the difference in light transmission of homeopathic CuSO4 preparations compared to controls.

  11. Single photon ionization and chemical ionization combined ion source based on a vacuum ultraviolet lamp for orthogonal acceleration time-of-flight mass spectrometry. (United States)

    Hua, Lei; Wu, Qinghao; Hou, Keyong; Cui, Huapeng; Chen, Ping; Wang, Weiguo; Li, Jinghua; Li, Haiyang


    A novel combined ion source based on a vacuum ultraviolet (VUV) lamp with both single photon ionization (SPI) and chemical ionization (CI) capabilities has been developed for an orthogonal acceleration time-of-flight mass spectrometer (oaTOFMS). The SPI was accomplished using a commercial 10.6 eV krypton discharge lamp with a photon flux of about 10(11) photons s(-1), while the CI was achieved through ion-molecule reactions with O(2)(+) reactant ions generated by photoelectron ionization at medium vacuum pressure (MVP). To achieve high ionization efficiency, the ion source pressure was elevated to 0.3 mbar and the photoionization length was extended to 36 mm. As a result, limits of detection (LODs) down to 3, 4, and 6 ppbv were obtained for benzene, toluene, and p-xylene in MVP-SPI mode, and values of 8 and 10 ppbv were obtained for toluene and chloroform, respectively, in SPI-CI mode. As it is feasible to switch between MVP-SPI mode and SPI-CI mode rapidly, this system is capable of monitoring complex organic mixtures with a wide range of ionization energies (IEs). The analytical capacity of this system was demonstrated by measuring dehydrogenation products of long-chain paraffins to olefins through direct capillary sampling and drinking water disinfection byproducts from chlorine through a membrane interface.

  12. [Rapid determination of nine components in the first extraction process of Xingnaojing injection by using ultraviolet spectroscopy]. (United States)

    Huang, Kai-Yi; Wei, Dan-Ni; Fang, Jin-Yang; Li, Xi-Yuan; Yan, Bin-Jun


    In this study, an analytical method based on ultraviolet spectroscopy was established for the rapid determination of nine components including isophorone, 4-methylene-isophorone, curcumenone, curcumenol, curdione, curzerenone, furanodienone, curcumol and germacrone in the first extraction process of Xingnaojing injection. 166 distillate samples of Gardeniae Fructus and Radix Curcumae were collected in the first extraction process of Xingnaojing injection. The ultraviolet spectra of these samples were collected, and the contents of the nine components in these samples were determined by high performance liquid chromatography. Least squares support vector machine and radial basis function artificial neural network were used to establish the multivariate calibration models between the ultraviolet spectra and the contents of the nine components. The results showed that the established ultraviolet spectrum analysis method can determine the contents of the nine components in the distillates accurately, with root mean square error of prediction of 0.068, 0.147, 0.215, 0.319, 1.01, 1.27, 0.764, 0.147, 0.610 mg•L⁻¹, respectively. This proposed method is a rapid, simple and low-cost tool for the monitoring and endpoint determination of the extraction process of Xingnaojing injection to reduce quality defects and variations. Copyright© by the Chinese Pharmaceutical Association.

  13. International Conference on Vacuum Ultraviolet Radiation Physics, 8th, Lunds Universitet, Sweden, Aug. 4-8, 1986, Proceedings (United States)

    Nilsson, Per-Olof (Editor); Nordgren, Joseph (Editor)


    The interactions of VUV radiation with solids are explored in reviews and reports of recent theoretical and experimental investigations from the fields of atomic and molecular physics, solid-state physics, and VUV instrumentation. Topics examined include photoabsorption and photoionization, multiphoton processes, plasma physics, VUV lasers, time-resolved spectroscopy, synchrotron radiation centers, solid-state spectroscopy, and dynamical processes involving localized levels. Consideration is given to the fundamental principles of photoemission, spin-polarized photoemission, inverse photoemission, semiconductors, organic materials, and adsorbates.

  14. Survivorship in micro fungi and crustacean resting stages during ultraviolet (UV) and vacuum land testing of EXPOSE unit (United States)

    Alekseev, Victor; Alekseev, Victor; Novikova, Nataliya; Sychev, Vladimir; Levinskikh, Margarita; Deshevaya, Elena; Brancelj, Anton; Malyavin, Stanislav

    Dormancy protects animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years. This phenomenon is perspective for space researches on interplanetary quarantine within space missions. Direct experiments in open space supported in principle the fact of survivorship of bacteria and fungi spores in open space during long time experiments (Novikova et al. 2007). The rate of survivorship in long-term mission was low but enough to conclude that biological invasion to Mars is a real danger. The possibility for resting stages to survive under UV treatment in vacuum without some protection was not clear. To test it dormant stages (spores) of primitive fungi Aspergillus versicolor, Aspergillus sydowii, Penicillium expansum, and Penicillium aurantiogriseum derived from ISS environment were used in the land EXPOSE imitation of outside space station UV and vacuum conditions. Survivorship in resting eggs of some crustaceans with dried (cladoceran Daphnia magna, fair-shrimp Streptocephalus torvicornis and ostracode Eucypris ornate from hemi desert Caspian area) and wet diapause state (copepod Mixodiaptomus tatricus from the Tatra mountains, altitude 1510 m) was tested also. The total UV dose of 9,1x10 to the 4th KJ/m2 during this imitation was accomplished with a SOL 2000 sun simulator lamp. The final vacuum value achieved during EST was 10 to the minus 6 Pa. Temperature during the experiment fluctuated in the range 19-25 o C. Micro fungi showed a high level of survivorship in samples treated with UV samples varied from 95 till 100 Supported by RFBR grant 07-04-00006.

  15. Vacuum ultraviolet photoionization and ab initio Investigations of methyl tert-butyl ether (MTBE) clusters and MTBE-water clusters (United States)

    Di Palma, Tonia M.; Bende, Attila


    The structures and energetics of neutral, ionized and protonated methyl tert-butyl ether (MTBE) clusters and (MTBE)m(H2O)n clusters are investigated by tunable vacuum-UV photoionization mass spectrometry and DFT calculations. While the mass spectra of bare MTBE clusters show unprotonated and protonated clusters ions, the mass spectra of mixed clusters show protonated ions that exhibit magic numbers that correspond to n = m - 2 combinations. Ab initio calculations show that in the larger clusters a multiple proton transfer leads to a protonated water core where all available hydrogen bonds interact with MTBE molecules. The resulting bond structure explains the cluster stability.

  16. Physico-chemical characterization of products from vacuum oil under delayed coking process by infrared spectroscopy and chemometrics methods (United States)

    Meléndez, L. V.; Cabanzo, R.; Mejía-Ospino, E.; Guzmán, A.


    Eight vacuum residues and their delayed coking liquids products from Colombian crude were study by infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and principal component analysis (PCA). For the samples the structural parameters of aromaticity factor (fa), alifaticity (A2500-3100cm-1), aromatic condensation degree (GCA), length of aliphatic chains (LCA) and aliphatic chain length associated with aromatic (LACAR) were determined through the development of a methodology, which includes the previous processing of spectroscopy data, identifying the regions in the IR spectra of greatest variance using PCA and molecules patterns. The parameters were compared with the results obtained from proton magnetic resonance (1H-NMR) and 13C-NMR. The results showed the influence and correlation of structural parameters with some physicochemical properties such as API gravity, weight percent sulphur (% S) and Conradson carbon content (% CCR)

  17. Electronic states localized at surface defects on Cu(755) studied by angle-resolved ultraviolet photoelectron spectroscopy using synchrotron radiation

    CERN Document Server

    Ogawa, K; Namba, H


    'Regularly stepped' and 'defective' surfaces of Cu(755) were prepared by low- and high-temperature annealing, respectively, of a clean specimen. Electronic states on both surfaces were studied by angle-resolved ultraviolet photoelectron spectroscopy using synchrotron radiation. On the defective Cu(755), we found a new photoelectron peak due to surface defects just below the Fermi level. The dispersion profile of the defect state is derived to be almost flat, which demonstrates the localized nature of the defects. High activity to oxygen adsorption of the defect state was revealed. (author)

  18. Production of reactive species using vacuum ultraviolet photodissociation as a tool for studying their effects in plasma medicine: simulations and measurements (United States)

    Ono, Ryo; Tokumitsu, Yusuke; Zen, Shungo; Yonemori, Seiya


    We propose a method for producing OH, H, O, O3, and O2(a1Δg) using the vacuum ultraviolet photodissociation of H2O and O2 as a tool for studying the reaction processes of plasma medicine. For photodissociation, an H2O/He or O2/He mixture flowing in a quartz tube is irradiated by a Xe2 or Kr2 excimer lamp. The effluent can be applied to a target. Simulations show that the Xe2 lamp method can produce OH radicals within 0.1-1 ppm in the effluent at 5 mm from a quartz tube nozzle. This is comparable to those produced by a helium atmospheric-pressure plasma jet (He-APPJ) currently used in plasma medicine. The Xe2 lamp method also produces H atoms of, at most, 6 ppm. In contrast, the maximum O densities produced by the Xe2 and Kr2 lamp methods are 0.15 ppm and 2.5 ppm, respectively; these are much lower than those from He-APPJ (several tens of ppm). Both lamp methods can produce ozone at concentrations above 1000 ppm and O2(a1Δg) at tens of ppm. The validity of the simulations is verified by measuring the O3 and OH densities produced by the Xe2 lamp method using ultraviolet absorption and laser-induced fluorescence. The differences between the measured and simulated densities for O3 and OH are 20% and factors of 3-4, respectively.

  19. Proceedings of the eighth international colloquium on ultraviolet and x-ray spectroscopy of astrophysical and laboratory plasmas (IAU colloquium 86)

    Energy Technology Data Exchange (ETDEWEB)


    This volume represents the Proceedings of the Eighth International Colloquium on Ultraviolet and X-Ray Spectroscopy of Astrophysical and Laboratory Plasmas. The aim of this series of colloquia has been to bring together workers in the fields of astrophysical spectroscopy, laboratory spectroscopy and atomic physics in order to exchange ideas and results on problems which are common to these different disciplines. In addition to the presented papers there was a poster paper session. (WRF)

  20. Fourier Transform Infrared (FTIR) Spectroscopy, Ultraviolet Resonance Raman (UVRR) Spectroscopy, and Atomic Force Microscopy (AFM) for Study of the Kinetics of Formation and Structural Characterization of Tau Fibrils. (United States)

    Ramachandran, Gayathri


    Kinetic studies of tau fibril formation in vitro most commonly employ spectroscopic probes such as thioflavinT fluorescence and laser light scattering or negative stain transmission electron microscopy. Here, I describe the use of Fourier transform infrared (FTIR) spectroscopy, ultraviolet resonance Raman (UVRR) spectroscopy, and atomic force microscopy (AFM) as complementary probes for studies of tau aggregation. The sensitivity of vibrational spectroscopic techniques (FTIR and UVRR) to secondary structure content allows for measurement of conformational changes that occur when the intrinsically disordered protein tau transforms into cross-β-core containing fibrils. AFM imaging serves as a gentle probe of structures populated over the time course of tau fibrillization. Together, these assays help further elucidate the structural and mechanistic complexity inherent in tau fibril formation.

  1. Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy


    Watanabe, Yoshihide; Nishimura, Yusaku F.; Suzuki, Ryo; Uehara, Hiromitsu; Nimura, Tomoyuki; Beniya, Atsushi; Isomura, Noritake; Asakura, Kiyotaka; Takakusagi, Satoru


    A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitat...

  2. Ultraviolet radiation and nanoparticle induced intracellular free radicals generation measured in human keratinocytes by electron paramagnetic resonance spectroscopy. (United States)

    Rancan, F; Nazemi, B; Rautenberg, S; Ryll, M; Hadam, S; Gao, Q; Hackbarth, S; Haag, S F; Graf, C; Rühl, E; Blume-Peytavi, U; Lademann, J; Vogt, A; Meinke, M C


    Several nanoparticle-based formulations used in cosmetics and dermatology are exposed to sunlight once applied to the skin. Therefore, it is important to study possible synergistic effects of nanoparticles and ultraviolet radiation. Electron paramagnetic resonance spectroscopy (EPR) was used to detect intracellular free radicals induced by ultraviolet B (UVB) radiation and amorphous silica nanoparticle and to evaluate the influence of nanoparticle surface chemistry on particle cytotoxicity toward HaCaT cells. Uncoated titanium dioxide nanoparticles served as positive control. In addition, particle intracellular uptake, viability, and induction of interleukin-6 were measured. We found that photo-activated titanium dioxide particles induced a significant amount of intracellular free radicals. On the contrary, no intracellular free radicals were generated by the investigated silica nanoparticles in the dark as well as under UVB radiation. However, under UVB exposure, the non-functionalized silica nanoparticles altered the release of IL-6. At the same concentrations, the amino-functionalized silica nanoparticles had no influence on UVB-induced IL-6 release. EPR spectroscopy is a useful technique to measure nanoparticle-induced intracellular free radicals. Non-toxic concentrations of silica particles enhanced the toxicity of UVB radiation. This synergistic effect was not mediated by particle-generated free radicals and correlated with particle surface charge and intracellular distribution. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Thermal desorption/tunable vacuum-ultraviolet time-of-flight photoionization aerosol mass spectrometry for investigating secondary organic aerosols in chamber experiments. (United States)

    Fang, Wenzheng; Gong, Lei; Shan, Xiaobin; Liu, Fuyi; Wang, Zhenya; Sheng, Liusi


    This paper describes thermal desorption/tunable vacuum-ultraviolet photoionization time-of-flight aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for the real-time analysis of secondary organic aerosols (SOAs) in smog chamber experiments. SOAs are sampled directly from atmospheric pressure and are focused through an aerodynamic lens assembly into the mass spectrometer. Once the particles have entered the source region, they impact on a heater and are vaporized. The nascent vapor is then softly ionized by tunable VUV synchrotron radiation. TD-VUV-TOF-PIAMS was used in conjunction with the smog chamber to study SOA formation from the photooxidation of toluene with hydroxyl radicals. The ionization energies (IEs) of these SOA products are sometimes very different with each other. As the ideal photon source is tunable, its energy can be adjusted for each molecular to be ionized. The mass spectra obtained at different photon energies are then to be useful for molecular identification. Real-time analysis of the mass spectra of SOAs is compared with previous off-line measurements. These results illustrate the potential of TD-VUV-TOF-PIAMS for direct molecular characterization of SOAs in smog chamber experiments.

  4. Effect of the methyl substitution on the combustion of two methylheptane isomers: Flame chemistry using vacuum-ultraviolet (VUV) photoionization mass spectrometry

    KAUST Repository

    Selim, Hatem


    Alkanes with one or more methyl substitutions are commonly found in liquid transportation fuels, so a fundamental investigation of their combustion chemistry is warranted. In the present work, stoichiometric low-pressure (20 Torr) burner-stabilized flat flames of 2-methylheptane and 3-methylheptane were investigated. Flame species were measured via time-of-flight molecular-beam mass spectrometry, with vacuum-ultraviolet (VUV) synchrotron radiation as the ionization source. Mole fractions of major end-products and intermediate species (e.g., alkanes, alkenes, alkynes, aldehydes, and dienes) were quantified axially above the burner surface. Mole fractions of several free radicals were also measured (e.g., CH3, HCO, C2H3, C3H3, and C3H5). Isomers of different species were identified within the reaction pool by an energy scan between 8 and 12 eV at a distance of 2.5 mm away from the burner surface. The role of methyl substitution location on the alkane chain was determined via comparisons of similar species trends obtained from both flames. The results revealed that the change in CH3 position imposed major differences on the combustion of both fuels. Comparison with numerical simulations was performed for kinetic model testing. The results provide a comprehensive set of data about the combustion of both flames, which can enhance the erudition of both fuels combustion chemistry and also improve their chemical kinetic reaction mechanisms. © 2015 American Chemical Society.

  5. Determination of ionization energies of CnN (n=4-12): Vacuum-ultraviolet (VUV) photoionization experiments and theoretical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kostko, Oleg; Zhou, Jia; Sun, Bian Jian; Lie, Jie Shiuan; Chang, Agnes H.H.; Kaiser, Ralf I.; Ahmed, Musahid


    Results from single photon vacuum ultraviolet photoionization of astrophysically relevant CnN clusters, n = 4 - 12, in the photon energy range of 8.0 eV to 12.8 eV are presented. The experimental photoionization efficiency curves, combined with electronic structure calculations, provide improved ionization energies of the CnN species. A search through numerous nitrogen-terminated CnN isomers for n=4-9 indicates that the linear isomer has the lowest energy, and therefore should be the most abundant isomer in the molecular beam. Comparison with calculated results also shed light on the energetics of the linear CnN clusters, particularly in the trends of the even-carbon and the odd-carbon series. These results can help guide the search of potential astronomical observations of these neutral molecules together with their cations in highly ionized regions or regions with a high UV/VUV photon flux (ranging from the visible to VUV with flux maxima in the Lyman- region) in the interstellar medium.

  6. Determination of ionization energies of CnN (n=4-12): Vacuum-ultraviolet (VUV) photoionization experiments and theoretical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Kostko, Oleg; Zhou, Jia; Sun, Bian Jian; Lie, Jie Shiuan; Chang, Agnes H.H.; Kaiser, Ralf I.; Ahmed, Musahid


    Results from single photon vacuum ultraviolet photoionization of astrophysically relevant CnN clusters, n = 4 - 12, in the photon energy range of 8.0 eV to 12.8 eV are presented. The experimental photoionization efficiency curves, combined with electronic structure calculations, provide improved ionization energies of the CnN species. A search through numerous nitrogen-terminated CnN isomers for n=4-9 indicates that the linear isomer has the lowest energy, and therefore should be the most abundant isomer in the molecular beam. Comparison with calculated results also shed light on the energetics of the linear CnN clusters, particularly in the trends of the even-carbon and the odd-carbon series. These results can help guide the search of potential astronomical observations of these neutral molecules together with their cations in highly ionized regions or regions with a high UV/VUV photon flux (ranging from the visible to VUV with flux maxima in the Lyman-a region) in the interstellar medium.

  7. Airfoil sampling of a pulsed Laval beam with tunable vacuum ultraviolet synchrotron ionization quadrupole mass spectrometry: application to low-temperature kinetics and product detection. (United States)

    Soorkia, Satchin; Liu, Chen-Lin; Savee, John D; Ferrell, Sarah J; Leone, Stephen R; Wilson, Kevin R


    A new pulsed Laval nozzle apparatus with vacuum ultraviolet (VUV) synchrotron photoionization quadrupole mass spectrometry is constructed to study low-temperature radical-neutral chemical reactions of importance for modeling the atmosphere of Titan and the outer planets. A design for the sampling geometry of a pulsed Laval nozzle expansion has been developed that operates successfully for the determination of rate coefficients by time-resolved mass spectrometry. The new concept employs airfoil sampling of the collimated expansion with excellent sampling throughput. Time-resolved profiles of the high Mach number gas flow obtained by photoionization signals show that perturbation of the collimated expansion by the airfoil is negligible. The reaction of C(2)H with C(2)H(2) is studied at 70 K as a proof-of-principle result for both low-temperature rate coefficient measurements and product identification based on the photoionization spectrum of the reaction product versus VUV photon energy. This approach can be used to provide new insights into reaction mechanisms occurring at kinetic rates close to the collision-determined limit.

  8. Vacuum ultraviolet emission spectrum measurement of a microwave-discharge hydrogen-flow lamp in several configurations: Application to photodesorption of CO ice

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.-J.; Wu, C.-Y. R. [Space Sciences Center and Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-1341 (United States); Chuang, K.-J.; Chu, C.-C.; Yih, T.-S. [Department of Physics, National Central University, Jhongli City, Taoyuan County 32054, Taiwan (China); Muñoz Caro, G. M. [Centro de Astrobiología, INTA-CSIC, Torrejón de Ardoz, E-28850 Madrid (Spain); Nuevo, M. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Ip, W.-H., E-mail: [Graduate Institute of Astronomy, National Central University, Jhongli City, Taoyuan County 32049, Taiwan (China)


    We report measurements of the vacuum ultraviolet (VUV) emission spectra of a microwave-discharge hydrogen-flow lamp (MDHL), a common tool in astrochemistry laboratories working on ice VUV photoprocessing. The MDHL provides hydrogen Ly-α (121.6 nm) and H{sub 2} molecular emission in the 110-180 nm range. We show that the spectral characteristics of the VUV light emitted in this range, in particular the relative proportion of Ly-α to molecular emission bands, strongly depend on the pressure of H{sub 2} inside the lamp, the lamp geometry (F type versus T type), the gas used (pure H{sub 2} versus H{sub 2} seeded in He), and the optical properties of the window used (MgF{sub 2} versus CaF{sub 2}). These different configurations are used to study the VUV irradiation of CO ice at 14 K. In contrast to the majority of studies dedicated to the VUV irradiation of astrophysical ice analogs, which have not taken into consideration the emission spectrum of the MDHL, our results show that the processes induced by photons in CO ice from a broad energy range are different and more complex than the sum of individual processes induced by monochromatic sources spanning the same energy range, as a result of the existence of multistate electronic transitions and discrepancy in absorption cross sections between parent molecules and products in the Ly-α and H{sub 2} molecular emission ranges.

  9. A new membrane inlet interface of a vacuum ultraviolet lamp ionization miniature mass spectrometer for on-line rapid measurement of volatile organic compounds in air. (United States)

    Hou, Keyong; Wang, Junde; Li, Haiyang


    A novel membrane inlet interface coupled to a single-photon ionization (SPI) miniature time-of-flight mass spectrometer has been developed for on-line rapid measurement of volatile organic compounds (VOCs). The vacuum ultraviolet (VUV) light source for SPI was a commercial krypton discharge lamp with photon energy of 10.6 eV and photon flux of 10(10) photons/s. The experimental results showed that the sensitivity was 5 times as high as obtained with the traditional membrane inlet. The enrichment efficiency could be adjusted in the range of 10 to 20 times for different VOCs when a buffer cell was added to the inlet interface, and the memory effect was effectively eliminated. A detection limit as low as 25 parts-per-billion by volume (ppbv) for benzene has been achieved, with a linear dynamic range of three orders of magnitude. The rise times were 6 s, 10 s and 15 s for benzene, toluene and p-xylene, respectively, and the fall time was only 6 s for all of these compounds. The analytical capacity of this system was demonstrated by the on-line analysis of VOCs in single puff mainstream cigarette smoke, in which more than 50 compounds were detected in 2 s. Copyright 2007 John Wiley & Sons, Ltd.

  10. A straightforward method for Vacuum-Ultraviolet flux measurements: The case of the hydrogen discharge lamp and implications for solid-phase actinometry

    Energy Technology Data Exchange (ETDEWEB)

    Fulvio, D., E-mail:, E-mail:; Brieva, A. C.; Jäger, C. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Cuylle, S. H.; Linnartz, H. [Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, Leiden University, P.O. box 9513, 2300 RA Leiden (Netherlands); Henning, T. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)


    Vacuum-Ultraviolet (VUV) radiation is responsible for the photo-processing of simple and complex molecules in several terrestrial and extraterrestrial environments. In the laboratory such radiation is commonly simulated by inexpensive and easy-to-use microwave-powered hydrogen discharge lamps. However, VUV flux measurements are not trivial and the methods/devices typically used for this purpose, mainly actinometry and calibrated VUV silicon photodiodes, are not very accurate or expensive and lack of general suitability to experimental setups. Here, we present a straightforward method for measuring the VUV photon flux based on the photoelectric effect and using a gold photodetector. This method is easily applicable to most experimental setups, bypasses the major problems of the other methods, and provides reliable flux measurements. As a case study, the method is applied to a microwave-powered hydrogen discharge lamp. In addition, the comparison of these flux measurements to those obtained by O{sub 2} actinometry experiments allow us to estimate the quantum yield (QY) values QY{sub 122} = 0.44 ± 0.16 and QY{sub 160} = 0.87 ± 0.30 for solid-phase O{sub 2} actinometry.

  11. Hubble Space Telescope Ultraviolet spectroscopy of 14 low-redshift quasars

    NARCIS (Netherlands)

    Ganguly, R.; Kaastra, J.S.|info:eu-repo/dai/nl/070911134


    We present low-resolution ultraviolet spectra of 14 low-redshift quasars observed with the Hubble Space Telescope STIS as part of a Snapshot project to understand the relationship between quasar outflows and luminosity. The quasar is radio-loud but has a steep spectral index and a lobe-dominated

  12. Electronic “Edge” State on Molybdenite Basal Plane Observed by Ultrahigh-Vacuum Scanning Tunneling Microscopy and Spectroscopy (United States)

    Komiyama, Masaharu; Tomita, Hiroyuki; Yoda, Eisuke


    An electronic state heretofore unreported has been found on a cleaved basal plane of a natural molybdenite (MoS2) single crystal by ultrahigh-vacuum scanning tunneling microscopy (UHV-STM), and examined in detail both by STM and scanning tunneling spectroscopy (STS). The new electronic state resides on the edge of the upper terrace of MoS2(0001), manifesting itself in the form of bright ridges with a width of ca. 4 nm along the step edges in negatively sample-biased STM images. This ridge structure is nonexistent in STM images taken with positive sample biases. STS showed that the local density of states (LDOS) on such ridge structures is much higher than that on the terraces in the range of 0.2-1.2 eV below the Fermi edge. The nature and origin of this high LDOS at the step edges are discussed.

  13. Vacuum ultraviolet excited luminescence properties of sol–gel derived GdP{sub 5}O{sub 14}:Eu{sup 3+} powders

    Energy Technology Data Exchange (ETDEWEB)

    Mbarek, Aïcha [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Laboratoire de Chimie Industrielle, Ecole Nationale d' Ingénieurs de Sfax, Université de Sfax, BP W 3038, Sfax (Tunisia); Chadeyron, Geneviève, E-mail: [Clermont Université, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Boyer, Damien [Clermont Université, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Avignant, Daniel [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); Fourati, Mohieddine [Laboratoire de Chimie Industrielle, Ecole Nationale d' Ingénieurs de Sfax, Université de Sfax, BP W 3038, Sfax (Tunisia); Zambon, Daniel [Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 CLERMONT-FERRAND (France); and others


    Sol–gel route has successfully been used to synthesize pure and Eu{sup 3+} doped polycrystalline samples of the GdP{sub 5}O{sub 14} pentaphosphates. The as-prepared samples have structurally been characterized using X-ray diffraction. Optical properties in the vacuum ultraviolet (VUV) of Eu{sup 3+} activated GdP{sub 5}O{sub 14} samples prepared either by sol–gel process or solid-state reaction were investigated at room temperature for comparison. In this GdP{sub 5}O{sub 14} host matrix the P{sub 5}O{sub 14} ultraphosphate groups were proved to exhibit an efficient absorption in the VUV range. The excitation spectra recorded in the VUV-UV spectral region from 120 nm to 350 nm have revealed the presence of Gd{sup 3+} 4f–5d interconfiguration transitions, Gd{sup 3+}–O{sup 2−} and Eu{sup 3+}–O{sup 2−} charge transfer states(CTS)in addition to intraconfiguration transitions of Gd{sup 3+} ions.Furthermore the Gd{sup 3+}→Eu{sup 3+} energy transfer process was investigated and discussed in the framework of the multiphonon relaxation process. Besides, the GdP{sub 5}O{sub 14}:Eu{sup 3+} phosphor led to a strong red emission under 147/172 nm excitation, so that it can be considered as a promising red phosphor for mercury-free lamps and plasma display panels applications. -- Highlights: • Lanthanide pentaphosphates were synthesized by the sol–gel process. • A broad absorption was evidenced in the VUV range for GdP{sub 5}O{sub 14}:Eu{sup 3+}. • An efficient energy transfer was proved from pentaphosphate lattice to Eu{sup 3+} ions.

  14. 25 W of average power at 172 nm in the vacuum ultraviolet from flat, efficient lamps driven by interlaced arrays of microcavity plasmas (United States)

    Park, S.-J.; Herring, C. M.; Mironov, A. E.; Cho, J. H.; Eden, J. G.


    More than 25 W of average power and >800 W of peak power have been generated at λ =172 nm (h ν =7.2 eV) in the vacuum ultraviolet (VUV) from the Xe2 molecule in flat, 10 × 10 cm2 lamps having an active area and volume of 80 cm2 and interlaced arrays of microplasmas generated within cavities fabricated into an interior surface of the 20 % . For a bipolar voltage waveform driving frequency of 137 kHz and a 54% Xe/Ne gas fill mixture at a 300 K pressure of 550 Torr, the lamp generates as much as 31.5 W of average power and intensities >350 mW cm-2 in 40-60 μJ, 70±10 ns FWHM pulses produced in a burst mode-four pulses of 600-850 W peak power in every cycle of the driving waveform. The lamp intensity is uniform to within ±2.5% at ≥10 mm from its surface and average power varies linearly with pulse repetition frequency throughout the 18-135 kHz interval. The spectral breadth of the Xe dimer emission is ˜9 nm FWHM and time-resolved, spatial intensity maps show improved utilization of the power pulse (VṡI) with two or more microcavity arrays that are interleaved. This photonic source technology is capable of generating unprecedented power levels in the VUV spectral region (e.g., ˜2.5 kW m-2) with tiled lamps.

  15. Far Ultraviolet Spectroscopy of Old Novae. II. RR Pic, V533 Her, and DI Lac (United States)

    Sion, Edward M.; Godon, Patrick; Jones, Liam


    The old novae V533 Her (Nova Her 1963), DI Lac (Nova Lac 1910), and RR Pic (Nova Pic 1891) are in (or near) their quiescent stage, following their nova explosions, and continue to accrete at a high rate in the aftermath of their explosions. They exhibit continua that are steeply rising into the FUV, as well as absorption lines and emission lines of uncertain origin. All three have Far Ultraviolet Spectroscopic Explorer (FUSE) spectra that offer not only higher spectral resolution but also wavelength coverage extending down to the Lyman Limit. For DI Lac, we have matched these FUSE spectra with existing archival International Ultraviolet Explorer spectral coverage to broaden the FUV wavelength coverage. We adopted the newly determined interstellar reddening corrections of Selvelli & Gilmozzi. The dereddened FUV spectra have been modeled with our grids of optically thick accretion disks and hot, NLTE white dwarf (WD) photospheres. The results of our modeling analysis indicate that the hot components in RR Pic and V533 Her are likely to be accretion disks with mass accretion rates of 10-8 M ⊙ yr-1 and 10-9 M ⊙ yr-1 respectively. However, the disk cannot produce the observed absorption lines. For the WD to be the source of the absorption lines in these two systems, it must be very hot, with a radius several times its expected size (because the WD in these systems is massive, it has a smaller radius). For DI Lac, we find the best fit to be a disk with \\dot{M}={10}-10 {M}⊙ {{yr}}-1 with a 30,000 K WD. Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer (FUSE). FUSE was operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.

  16. Effect of high-energy neutral particles on extreme ultraviolet spectroscopy in large helical device. (United States)

    Dong, Chunfeng; Morita, Shigeru; Tokitani, Masayuki; Goto, Motoshi; Sakaue, Hiroyuki; Wang, Erhui; Zushi, Hideki


    Spectra measured by an extreme ultraviolet (EUV) spectrometer frequently suffer large spike noise when Large Helical Device is operated in low-density range (≤ 3 × 10(13) cm(-3)) with neutral beam injection (NBI). The spike noise completely disappears in electron cyclotron heating discharges. In order to examine the effect of NBI, a carbon filter with thickness of 150 nm was installed in the EUV spectrometer. As a result, the spike noise was reduced by an order of magnitude. It is experimentally verified that the spike noise is caused by escaping high-energy neutral particles resulting from the circulating high-energy hydrogen ions borne from NBI.

  17. X-ray and extreme ultraviolet spectroscopy on DIII-D (United States)

    Victor, B. S.; Allen, S. L.; Beiersdorfer, P.; Magee, E. W.


    Two spectrometers were installed to measure tungsten emission in the core of DIII-D plasmas during a metal rings experimental campaign. The spectral range of the high-resolution (1340 spectral channels), variable-ruled grating X-ray and Extreme Ultraviolet Spectrometer (XEUS) extends from 10-71 dot A. The spectral range of the second spectrometer, the Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), measures between 31-174 dot A. Three groups of tungsten lines were identified with XEUS: W38+-W45+ from 47-63 dot A, W27+-W35+ from 45-55 dot A, and W28+-W33+ from 16-30 dot A. Emission lines from tungsten charge states W28+, W43+, W44+, and W45+ are identified and the line amplitude is presented versus time. Peak emission of W43+-W45+ occurs between core Te=2.5-3 keV, and peak emission of W28+ occurs at core Tetrack the sawtooth cycle. Sensitivity to the sawtooth cycle and the correlation of the peak emission with core electron temperature show that these spectrometers track the on-axis tungsten emission of DIII-D plasmas.

  18. Ultraviolet spectroscopy of symbiotic nova V1016 Cyg with IUE and HST (United States)

    Sanad, M. R.


    We present International Ultraviolet Explorer (IUE) & Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) observations of the symbiotic nova V1016 Cyg through the period 1978 - 2000. Four spectra at different times revealing the changes in line fluxes are presented. The outflow velocity of the emitting region was calculated to be 900-2000 km s-1 (FWHM). The reddening of V1016 Cyg was determined from 2200 Å absorption feature to be E (B-V) = 0.36 ± 0.02. We calculated the fluxes of CIV 1550 Å & CIII] 1909 Å emission lines produced in a stellar wind from the hot white dwarf. We determined the average wind mass loss rate to be ˜2.3 × 10-6 M⊙, the average temperature of the emitting region to be ˜1.3 × 105 K, and an average ultraviolet luminosity to be ˜2 × 1035 erg s-1. The results show that there are modulations of line fluxes with time. We attributed these spectral modulations to the changes of density and temperature in the emitting region as a result of the variable stellar wind.

  19. Interstitial oxygen molecules in amorphous SiO2. I. Quantitative concentration analysis by thermal desorption, infrared photoluminescence, and vacuum-ultraviolet optical absorption (United States)

    Kajihara, Koichi; Hirano, Masahiro; Uramoto, Motoko; Morimoto, Yukihiro; Skuja, Linards; Hosono, Hideo


    The amount of oxygen molecules (O2) in amorphous SiO2(a-SiO2), also called interstitial O2, was quantitatively measured by combining thermal-desorption spectroscopy (TDS) with infrared photoluminescence (PL) measurements of interstitial O2 at 1272 nm while exciting with 1064-nm Nd: yttrium aluminum garnet laser light. It was found that the amount of O2 released by the TDS measurement is proportional to the intensity decrease of the PL band, demonstrating that a-SiO2 easily emits interstitial O2 during thermal annealing in vacuum. This correlation yielded the proportionality coefficient between the absolute concentration of interstitial O2 and its PL intensity normalized against the intensity of the fundamental Raman bands of a-SiO2. This relationship was further used to determine the optical-absorption cross section of the Schumann-Runge band of the interstitial O2 located at photon energies ≳6.5eV. This band is significantly redshifted and has a larger cross section compared to that of O2 in the gas phase.

  20. Investigation of optical fibers for gas-phase, ultraviolet laser-induced-fluorescence (UV-LIF) spectroscopy. (United States)

    Hsu, Paul S; Kulatilaka, Waruna D; Jiang, Naibo; Gord, James R; Roy, Sukesh


    We investigate the feasibility of transmitting high-power, ultraviolet (UV) laser pulses through long optical fibers for laser-induced-fluorescence (LIF) spectroscopy of the hydroxyl radical (OH) and nitric oxide (NO) in reacting and non-reacting flows. The fundamental transmission characteristics of nanosecond (ns)-duration laser pulses are studied at wavelengths of 283 nm (OH excitation) and 226 nm (NO excitation) for state-of-the-art, commercial UV-grade fibers. It is verified experimentally that selected fibers are capable of transmitting sufficient UV pulse energy for single-laser-shot LIF measurements. The homogeneous output-beam profile resulting from propagation through a long multimode fiber is ideal for two-dimensional planar-LIF (PLIF) imaging. A fiber-coupled UV-LIF system employing a 6 m long launch fiber is developed for probing OH and NO. Single-laser-shot OH- and NO-PLIF images are obtained in a premixed flame and in a room-temperature NO-seeded N(2) jet, respectively. Effects on LIF excitation lineshapes resulting from delivering intense UV laser pulses through long fibers are also investigated. Proof-of-concept measurements demonstrated in the current work show significant promise for fiber-coupled UV-LIF spectroscopy in harsh diagnostic environments such as gas-turbine test beds.

  1. Tunable ultrafast extreme ultraviolet source for time- and angle-resolved photoemission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dakovski, G. L.; Rodriguez, G. [MPA-CINT, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Li, Y.; Durakiewicz, T. [MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)


    We present a laser-based apparatus suitable for visible pump/extreme UV (XUV) probe time-, energy-, and angle-resolved photoemission spectroscopy utilizing high-harmonic generation from a noble gas. Tunability in a wide range of energies (currently 20-36 eV) is achieved by using a time-delay compensated monochromator, which also preserves the ultrashort duration of the XUV pulses. Using an amplified laser system at 10 kHz repetition rate, approximately 10{sup 9}-10{sup 10} photons/s per harmonic are made available for photoelectron spectroscopy. Parallel energy and momentum detection is carried out in a hemispherical electron analyzer coupled with an imaging detector. First applications demonstrate the capabilities of the instrument to easily select the probe wavelength of choice, to obtain angle-resolved photoemission maps (GaAs and URu{sub 2}Si{sub 2}), and to trace ultrafast electron dynamics in an optically excited semiconductor (Ge).

  2. Tunable ultrafast extreme ultraviolet source for time- and angle-resolved photoemission spectroscopy. (United States)

    Dakovski, G L; Li, Y; Durakiewicz, T; Rodriguez, G


    We present a laser-based apparatus suitable for visible pump/extreme UV (XUV) probe time-, energy-, and angle-resolved photoemission spectroscopy utilizing high-harmonic generation from a noble gas. Tunability in a wide range of energies (currently 20-36 eV) is achieved by using a time-delay compensated monochromator, which also preserves the ultrashort duration of the XUV pulses. Using an amplified laser system at 10 kHz repetition rate, approximately 10(9)-10(10) photons/s per harmonic are made available for photoelectron spectroscopy. Parallel energy and momentum detection is carried out in a hemispherical electron analyzer coupled with an imaging detector. First applications demonstrate the capabilities of the instrument to easily select the probe wavelength of choice, to obtain angle-resolved photoemission maps (GaAs and URu(2)Si(2)), and to trace ultrafast electron dynamics in an optically excited semiconductor (Ge).

  3. Ultraviolet spectroscopy of Comet Austin (1989c1) using a two-dimensional diode array detector (United States)

    Sahnow, David James

    A two-dimensional, photon-counting intensified photodiode array detector has been constructed and successfully tested in the laboratory and on a spectrograph in three sounding rocket flights. The detector is an extension of the one-dimensional intensified diode array detector used in the Hopkins Ultraviolet Telescope. Extensive laboratory measurements have shown that it can successfully centroid with sub-diode resolution, and can be used in place of ranicon detectors to measure the spectra of faint objects. The instrument successfully obtained long slit far-ultraviolet spectra (1250-1850 A) of Comet Austin (1989 c1) on 21 April 1990. Emissions of OI, CI, SI and CO were detected during the 270 seconds of data acquisition. The spectral resolution was 5.5 A, while the spatial resolution was limited by pointing jitter to approximately 30 arcseconds. The spatial profiles of the carbon and oxygen emissions show narrow enhancements which are suggestive of a cometary outburst which occurred 15-20 hours before the observation. The overall shape of the atomic carbon profile is similar to those measured during two observations of Comet Halley (1986 III), and is similarly incompatible with photodissociation of CO as its primary source, as determined by model calculations. The CO profile, however, is consistent with that of a parent molecule evaporating directly from the nucleus, with a production rate of 4 plus or minus 1 x 1027 molecules s-1. The O I lambda 1304 emission, also similar in spatial shape to that detected in Halley, includes a contribution due to Bowen fluorescence induced by solar HI Lyman-beta, and its profile can be understood as that due to the photodissociation of H2O, with a production rate of 6.2 plus or minus 0.3 x 1028 molecules s-1, giving an abundance of CO relative to water of 6.5 percent. Spatial profiles of SI lambda 1814 were also obtained, with profiles attributable to that of a daughter product of short-lived species such as CS2 and H2S.

  4. Vibrational autoionization of state-selective jet-cooled methanethiol (CH3SH) investigated with infrared vacuum-ultraviolet photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Min; Sen, Zhitao; Pratt, S. T.; Lee, Yuan-Pern


    Vibrational autoionization of Rydberg states provides key information about nonadiabatic processes above an ionization threshold. We employed time-of-flight mass detection of CH3SH+ to record vibrational-state selective photo-ionization efficiency (PIE) spectra of jet-cooled methanethiol (CH3SH) on exciting CH3SH to a specific vibrationally excited state with an infrared (IR) laser, followed by excitation with a tunable laser in the vacuum-ultraviolet (VUV) region for ionization. Autoionizing Rydberg states assigned to the ns, np, nd and nf series are identified. When IR light at 2601 (ν3, SH stretching mode) and 2948 cm-12, CH3 symmetric stretching mode) was employed, the Rydberg series converged to the respective vibrationally excited (ν3 and ν2) states of CH3SH+. When IR light at 3014 cm-1 (overlapped ν19, CH3 antisymmetric stretching and CH2 antisymmetric stretching modes) was employed, two converging limits towards vibrationally excited states (ν1 and ν9) of CH3SH+ were observed. In contrast, when IR light at 2867 cm-1 (2ν10, overtone of CH3 deformation mode) and 2892 cm-1 (2ν4, overtone of CH2 scissoring mode) was employed, both Δν = -1 and Δν = -2 ionization transitions were observed; there is evidence for direct ionization from the initial state into the CH3SH+ (v4+ = 1) continuum. In all observed IR-VUV-PIE spectra, the ns and nd series show intensity greater than the other Rydberg series, which is consistent with the fact that the highest-occupied molecular orbital of CH3SH is a p-like lone pair orbital on the S atom. The quantum yields for autoionization of various vibrational excited states are discussed.

  5. A Fourier transform spectrometer without a beam splitter for the vacuum ultraviolet range: From the optical design to the first UV spectrum. (United States)

    de Oliveira, N; Joyeux, D; Phalippou, D; Rodier, J C; Polack, F; Vervloet, M; Nahon, L


    We describe a Fourier transform (FT) spectrometer designed to operate down to 60 nm (20 eV) on a synchrotron radiation beamline for high resolution absorption spectrometry. As far as we know, such an instrument is not available below 140 nm mainly because manufacturing accurate and efficient beam splitters remains a major problem at these wavelengths, especially if a wide bandwidth operation is desired. In order to overcome this difficulty, we developed an interferometer based on wave front division instead of amplitude division. It relies on a modified Fresnel bimirror configuration that requires only flat mirrors. The instrument provides path difference scanning through the translation of one reflector. During the scanning, the moving reflector is controlled by an optical system that keeps its direction constant within a tolerable value and provides an accurate interferometric measurement of the path difference variation. Therefore, a regular interferogram sampling is obtained, producing a nominal spectral impulse response and an accurate spectral calibration. The first results presented in this paper show a measured spectral resolution of delta(sigma)=0.33 cm-1 (interval between spectral samples). This was obtained with a sampling interval of 29 nm (path difference) and 512 K samples from a one-sided interferogram using a cosine FT. Such a sampling interval should allow the recording of large bandwidth spectra down to lambda=58 nm with an ultimate resolving power of 500,000 at this wavelength. In order to check the instrument performances, we first recorded an interferogram from a He-Ne stabilized laser. This provided the actual spectral impulse function, which was found to be fully satisfactory. The determination of the impulse response distortion and of the noise on the vacuum ultraviolet (VUV) spectral range provided accurate information in the sampling error profile over a typical scan. Finally, the instrument has been moved to the SU5 undulator

  6. Determination of geographical origin of alcoholic beverages using ultraviolet, visible and infrared spectroscopy: A review (United States)

    Uríčková, Veronika; Sádecká, Jana


    The identification of the geographical origin of beverages is one of the most important issues in food chemistry. Spectroscopic methods provide a relative rapid and low cost alternative to traditional chemical composition or sensory analyses. This paper reviews the current state of development of ultraviolet (UV), visible (Vis), near infrared (NIR) and mid infrared (MIR) spectroscopic techniques combined with pattern recognition methods for determining geographical origin of both wines and distilled drinks. UV, Vis, and NIR spectra contain broad band(s) with weak spectral features limiting their discrimination ability. Despite this expected shortcoming, each of the three spectroscopic ranges (NIR, Vis/NIR and UV/Vis/NIR) provides average correct classification higher than 82%. Although average correct classification is similar for NIR and MIR regions, in some instances MIR data processing improves prediction. Advantage of using MIR is that MIR peaks are better defined and more easily assigned than NIR bands. In general, success in a classification depends on both spectral range and pattern recognition methods. The main problem still remains the construction of databanks needed for all of these methods.

  7. Spectroscopy of a Balmer-dominated filament in the Cygnus Loop with the Hopkins Ultraviolet Telescope (United States)

    Long, Knox S.; Blair, William P.; Vancura, Olaf; Bowers, Charles W.; Davidsen, Arthur F.; Raymond, John C.


    A fair UV spectrum of a nonradiative filament in the Cygnus Loop covering the wavelength range 830-1860 A at 3.5-A resolution was obtained using the Hopkins Ultraviolet Telescope (HUT) on the Astro-1 space shuttle mission. Nonradiative shock models which include a more sophisticated treatment of Lyman line transfer are calculated. It is found that the HUT spectrum can be explained in terms of a shock with velocity 175-185 km/s propagating into a low-density medium. This shock velocity can be reconciled with the 135-km/s width of the broad component of H-alpha in this filament if equilibration of the postshock electron and ion temperatures proceeds much more rapidly than Coulomb equilibration time scales. The time required for a 180-km/s shock to develop a partial recombination zone is short, about 200 yr if n is approximately equal to 2/cu cm. This suggests that the shock is decelerating as it encounters denser material. The current analysis patently favors rapid equilibration of electrons and ions behind the shock.

  8. Robust High-Resolution Imaging and Quantitative Force Spectroscopy in Vacuum with Tuned-Oscillator Atomic Force Microscopy. (United States)

    Schwarz, Udo; Dagdeviren, Omur; GöTzen, Jan; HöLscher, Hendrik; Altman, Eric

    Atomic force microscopy and spectroscopy are based on locally detecting the interactions between a surface and a sharp probe tip. For highest resolution imaging, noncontact modes that avoid tip-sample contact are used; control of the tip's vertical position is accomplished by oscillating the tip and detecting perturbations induced by its interaction with the surface potential. Due to this potential's nonlinear nature, however, achieving reliable control of the tip-sample distance is challenging, so much so that despite its power vacuum-based noncontact atomic force microscopy has remained a niche technique. Here we introduce a new pathway to distance control that prevents instabilities by externally tuning the oscillator's response characteristics. A major advantage of this operational scheme is that it delivers robust position control in both the attractive and repulsive regimes with only one feedback loop, thereby providing an easy-to-implement route to atomic resolution imaging and quantitative tip-sample interaction force measurement. Financial support from National Science Foundation through the Yale Materials Research Science and Engineering Center (Grant No. MRSEC DMR-1119826) is gratefully acknowledged.

  9. Transmission and fluorescence X-ray absorption spectroscopy cell/flow reactor for powder samples under vacuum or in reactive atmospheres

    KAUST Repository

    Hoffman, A. S.


    X-ray absorption spectroscopy is an element-specific technique for probing the local atomic-scale environment around an absorber atom. It is widely used to investigate the structures of liquids and solids, being especially valuable for characterization of solid-supported catalysts. Reported cell designs are limited in capabilities—to fluorescence or transmission and to static or flowing atmospheres, or to vacuum. Our goal was to design a robust and widely applicable cell for catalyst characterizations under all these conditions—to allow tracking of changes during genesis and during operation, both under vacuum and in reactive atmospheres. Herein, we report the design of such a cell and a demonstration of its operation both with a sample under dynamic vacuum and in the presence of gases flowing at temperatures up to 300 °C, showing data obtained with both fluorescence and transmission detection. The cell allows more flexibility in catalyst characterization than any reported.

  10. Generation of bright circularly-polarized extreme ultraviolet high harmonics for magnetic circular dichroism spectroscopy

    CERN Document Server

    Kfir, Ofer; Turgut, Emrah; Knut, Ronny; Zusin, Dmitriy; Popmintchev, Dimitar; Popmintchev, Tenio; Nembach, Hans; Shaw, Justin M; Fleicher, Avner; Kapteyn, Henry; Murnane, Margaret; Cohen, Oren


    Circularly-polarized extreme UV and X-ray radiation provides valuable access to the structural, electronic and magnetic properties of materials. To date, such experiments have been possible only using large-scale free-electron lasers or synchrotrons. Here we demonstrate the first bright extreme UV circularly-polarized high harmonics and use this new light source for magnetic circular dichroism measurements at the M-shell absorption edges of cobalt. This work paves the way towards element-specific imaging and spectroscopy of multiple elements simultaneously in magnetic and other chiral media with very high spatio-temporal resolution, all on a tabletop.

  11. High-resolution pulse-counting array detectors for imaging and spectroscopy at ultraviolet wavelengths (United States)

    Timothy, J. Gethyn; Bybee, Richard L.


    The performance characteristics of multianode microchannel array (MAMA) detector systems which have formats as large as 256 x 1024 pixels and which have application to imaging and spectroscopy at UV wavelengths are evaluated. Sealed and open-structure MAMA detector tubes with opaque CsI photocathodes can determine the arrival time of the detected photon to an accuracy of 100 ns or better. Very large format MAMA detectors with CsI and Cs2Te photocathodes and active areas of 52 x 52 mm (2048 x 2048 pixels) will be used as the UV solar blind detectors for the NASA STIS.

  12. Study of the Kinetics Adsorption of Organic Pollutants on Modified Cellulosic Polymer Using Ultraviolet-Visible Spectroscopy

    Directory of Open Access Journals (Sweden)

    Djamila Ghemati


    Full Text Available We report a study on the formation of the complex acrylamidomethylated-β-cyclodextrin, then on the grafting on cellulosic polymer. The grafting is initiated by ceric ions Ce(IV and confirmed by infrared spectroscopy analysis (FTIR. Scanning electron microscopy (SEM analysis was carried out to evaluate properties of structure and surface of grafted polymers. The experiments of the study of adsorption of balance of phenol and hydroquinone and a reactive dye, acid dyes, and cationic dyes using ultraviolet-visible microscopy were made in aqueous solutions for 24 hours at different pH. Our results indicate formation of a permanent chemical bond between β-cyclodextrin and polymers material. The cellulosic polymers can effectively be modified without significant change in the structural properties. Then, the results of organic pollutants adsorption in aqueous medium show the aptitude of the polymer modified to fix the phenol derivatives and synthetics dyes and used in the processing industrial liquid waste. The differences in adsorption capacities may be due to the effect of dye structure. The negative value of free energy change indicated the spontaneous nature of adsorption.

  13. Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy. (United States)

    Zürch, Michael; Chang, Hung-Tzu; Kraus, Peter M; Cushing, Scott K; Borja, Lauren J; Gandman, Andrey; Kaplan, Christopher J; Oh, Myoung Hwan; Prell, James S; Prendergast, David; Pemmaraju, Chaitanya D; Neumark, Daniel M; Leone, Stephen R


    Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si0.25Ge0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M4,5-edge (∼30 eV) allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons across the direct and indirect band gap into conduction band (CB) valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct [Formula: see text] and Si0.25Ge0.75 indirect gaps ([Formula: see text]) are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si0.25Ge0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution.

  14. Ultraviolet absorption and excitation spectroscopy of rare-earth-doped glass fibers derived from glassy and crystalline preforms (United States)

    Dragic, Peter D.; Liu, Yuh-Shiuan; Galvin, Thomas C.; Eden, J. G.


    Ultraviolet absorption and laser excitation spectroscopy (LES) measurements are presented for rare-earth-doped optical fibers produced from both glassy and crystalline preforms. Absorption spectra are obtained via broad-spectrum UV LEDs emitting in the 250nm region. LES measurements are obtained utilizing a tunable UV laser source. The tunable laser employed is a frequency-doubled titanium:sapphire laser-pumped optical parametric amplifier (OPA) operating down to a minimum wavelength of about 225nm. Our results indicate a roughly linear relationship between the concentration of oxygen deficiency centers (ODC) and rare-earth content, regardless of the preform type, and the slope of the line is found to vary significantly with the rare earth. Additionally, LES measurements are used to elucidate the energy transfer mechanism from pumping in the UV to emission by the rare-earth. In all cases the fibers are Al codoped and those produced from glassy preforms are manufactured via standard methods. Fibers produced from crystalline preforms start with a pure silica-sleeved rare-earth doped YAG crystal rod that becomes glassy (amorphous) post-draw.

  15. Detection of carcinogenic metals in kidney stones using ultraviolet laser-induced breakdown spectroscopy. (United States)

    Khalil, Ahmed Asaad I; Gondal, Mohammed A; Shemis, Mohamed; Khan, Irfan S


    The UV single-pulsed (SP) laser-induced breakdown spectroscopy (LIBS) system was developed to detect the carcinogenic metals in human kidney stones extracted through the surgical operation. A neodymium yttrium aluminium garnet laser operating at 266 nm wavelength and 20 Hz repetition rate along with a spectrometer interfaced with an intensified CCD (ICCD) was applied for spectral analysis of kidney stones. The ICCD camera shutter was synchronized with the laser-trigger pulse and the effect of laser energy and delay time on LIBS signal intensity was investigated. The experimental parameters were optimized to obtain the LIBS plasma in local thermodynamic equilibrium. Laser energy was varied from 25 to 50 mJ in order to enhance the LIBS signal intensity and attain the best signal to noise ratio. The parametric dependence studies were important to improve the limit of detection of trace amounts of toxic elements present inside stones. The carcinogenic metals detected in kidney stones were chromium, cadmium, lead, zinc, phosphate, and vanadium. The results achieved from LIBS system were also compared with the inductively coupled plasma-mass spectrometry analysis and the concentration detected with both techniques was in very good agreement. The plasma parameters (electron temperature and density) for SP-LIBS system were also studied and their dependence on incident laser energy and delay time was investigated as well.

  16. Ultraviolet Spectroscopy Used to Fingerprint Five Wild-Grown Edible Mushrooms (Boletaceae Collected from Yunnan, China

    Directory of Open Access Journals (Sweden)

    Yan Li


    Full Text Available Nowadays, wild-grown edible mushrooms which are natural, nutritious, and healthy get more and more popular by large consumers. In this paper, UV spectra of different Boletaceae mushrooms with the aid of partial least squares discriminant analysis (PLS-DA and hierarchical cluster analysis (HCA were shown to be a practical and rapid method for discrimination purpose. The specimens of Boletus edulis, Boletus ferrugineus, Boletus tomentipes, Leccinum rugosiceps, and Xerocomus sp. were described based on the UV spectra. From the results, all the specimens were characterized by strong absorption at the wavelengths of 274 and 284 nm and showed the shoulder at 296 nm. However, changes could be seen in the peak heights at the same wavelength for different samples. After analyzing by chemometrics, visual discrimination among samples was presented and the relationships among them were also obtained. This study showed that UV spectroscopy combined with chemometrics methods could be used successfully as a simple and effective approach for characterization of these five wild-grown edible mushrooms at species and genus levels. Meanwhile, this rapid and simple methodology could also provide reference for the discrimination of edible mushrooms.

  17. HST Ultraviolet Spectroscopy of the Dusty, Molecular Gas in Planck Cold Clumps (United States)

    Dirks, Cody


    The Planck Catalogue of Galactic Cold Clumps (PGCC) has provided a wealth of information about the cold, dusty ISM across the entire sky, identifying regions ranging from relatively diffuse cold clouds to pre-stellar cores in giant molecular clouds. This catalogue uses sub-millimeter emission arising from cold dust to determine the physical properties, morphology, and temperature of these regions. By combining this data with existing Hubble Space Telescope high-resolution UV spectra, we can probe the gas within these objects with the diagnostic capabilities of absorption line spectroscopy. Using data from Planck, Gaia, and CO emission studies, we have identified 22 stars which lie behind a PGCC region, and thus whose sightlines probe the cold gas associated with these objects. Here we report results from our studies of these sightlines, comparing the dust depletion to previous work done in studies of the diffuse ISM In particular, we find that the dust depletion decreases as projected distance from the centers of nearby PGCCs increases. Furthermore, we investigate the CO content of the cold gas using the numerous CO absorption bands in the UV. Additionally, by using neutral chlorine as a fiducial for H2, we calculate the CO-to-H2 ratio and explore the abundance of CO-dark gas. Finally, we compare the 12CO/13CO ratio to previous all-sky surveys, finding that our sightlines tend to show higher 12CO/13CO ratios when compared to other samples of Galactic sightlines.

  18. Clinical research device for ovarian cancer detection by optical spectroscopy in the ultraviolet C-visible (United States)

    George, Ronie; Chandrasekaran, Archana; Brewer, Molly A.; Hatch, Kenneth D.; Utzinger, Urs


    Early detection of ovarian cancer could greatly increase the likelihood of successful treatment. However, present detection techniques are not very effective, and symptoms are more commonly seen in later stage disease. Amino acids, structural proteins, and enzymatic cofactors have endogenous optical properties influenced by precancerous changes and tumor growth. We present the technical details of an optical spectroscopy system used to quantify these properties. A fiber optic probe excites the surface epithelium (origin of 90% of cases) over 270 to 580 nm and collects fluorescence and reflectance at 300 to 800 nm with four or greater orders of magnitude instrument to background suppression. Up to four sites per ovary are investigated on patients giving consent to oophorectomy and the system's in vivo optical evaluation. Data acquisition is completed within 20 s per site. We illustrate design, selection, and development of the components used in the system. Concerns relating to clinical use, performance, calibration, and quality control are addressed. In the future, spectroscopic data will be compared with histological biopsies from the corresponding tissue sites. If proven effective, this technique can be useful in screening women at high risk of developing ovarian cancer to determine whether oophorectomy is necessary.

  19. Low energy electron diffraction (LEED) and sum frequency generation (SFG) vibrational spectroscopy studies of solid-vacuum, solid-air and solid-liquid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hoffer, Saskia [Univ. of California, Berkeley, CA (United States)


    Electron based surface probing techniques can provide detailed information about surface structure or chemical composition in vacuum environments. The development of new surface techniques has made possible in situ molecular level studies of solid-gas interfaces and more recently, solid-liquid interfaces. The aim of this dissertation is two-fold. First, by using novel sample preparation, Low Energy Electron Diffraction (LEED) and other traditional ultra high vacuum (UHV) techniques are shown to provide new information on the insulator/vacuum interface. The surface structure of the classic insulator NaCl has been determined using these methods. Second, using sum frequency generation (SFG) surface specific vibrational spectroscopy studies were performed on both the biopolymer/air and electrode/electrolyte interfaces. The surface structure and composition of polyetherurethane-silicone copolymers were determined in air using SFG, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). SFG studies of the electrode (platinum, gold and copper)/electrolyte interface were performed as a function of applied potential in an electrochemical cell.

  20. Ultrafast carrier thermalization and trapping in silicon-germanium alloy probed by extreme ultraviolet transient absorption spectroscopy

    Directory of Open Access Journals (Sweden)

    Michael Zürch


    Full Text Available Semiconductor alloys containing silicon and germanium are of growing importance for compact and highly efficient photonic devices due to their favorable properties for direct integration into silicon platforms and wide tunability of optical parameters. Here, we report the simultaneous direct and energy-resolved probing of ultrafast electron and hole dynamics in a silicon-germanium alloy with the stoichiometry Si0.25Ge0.75 by extreme ultraviolet transient absorption spectroscopy. Probing the photoinduced dynamics of charge carriers at the germanium M4,5-edge (∼30 eV allows the germanium atoms to be used as reporter atoms for carrier dynamics in the alloy. The photoexcitation of electrons across the direct and indirect band gap into conduction band (CB valleys and their subsequent hot carrier relaxation are observed and compared to pure germanium, where the Ge direct ( Δ E gap , Ge , direct = 0.8   eV and Si0.25Ge0.75 indirect gaps ( Δ E gap , Si 0.25 Ge 0.75 , indirect = 0.95   eV are comparable in energy. In the alloy, comparable carrier lifetimes are observed for the X, L, and Γ valleys in the conduction band. A midgap feature associated with electrons accumulating in trap states near the CB edge following intraband thermalization is observed in the Si0.25Ge0.75 alloy. The successful implementation of the reporter atom concept for capturing the dynamics of the electronic bands by site-specific probing in solids opens a route to study carrier dynamics in more complex materials with femtosecond and sub-femtosecond temporal resolution.


    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guangtun Ben [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Comparat, Johan [Instituto de Física Teórica, UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Kneib, Jean-Paul; Delubac, Timothée [Laboratoire dástrophysique, Ecole Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, 1290 Versoix (Switzerland); Raichoor, Anand; Yèche, Christophe [CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette (France); Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Newman, Jeffrey [PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Zhou, Xu [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Schneider, Donald P., E-mail: [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)


    We present rest-frame near-ultraviolet (NUV) spectroscopy of star-forming galaxies (SFGs) at 0.6 < z < 1.2 from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) in SDSS-IV. One of the eBOSS programs is to obtain 2″ (about 15 kpc) fiber spectra of about 200,000 emission-line galaxies (ELGs) at redshift z ≳ 0.6. We use the data from the pilot observations of this program, including 8620 spectra of SFGs at 0.6 < z < 1.2. The median composite spectra of these SFGs at 2200 Å < λ < 4000 Å feature asymmetric, preferentially blueshifted non-resonant emission, Fe ii*, and blueshifted resonant absorption, e.g., Fe ii and Mg ii, indicating ubiquitous outflows driven by star formation at these redshifts. For the absorption lines, we find a variety of velocity profiles with different degrees of blueshift. Comparing our new observations with the literature, we do not observe the non-resonant emission in the small-aperture (<40 pc) spectra of local star-forming regions with the Hubble Space Telescope, and find the observed line ratios in the SFG spectra to be different from those in the spectra of local star-forming regions, as well as those of quasar absorption-line systems in the same redshift range. We introduce an outflow model that can simultaneously explain the multiple observed properties and suggest that the variety of absorption velocity profiles and the line ratio differences are caused by scattered fluorescent emission filling in on top of the absorption in the large-aperture eBOSS spectra. We develop an observation-driven, model-independent method to correct the emission infill to reveal the true absorption profiles. Finally, we show that the strengths of both the non-resonant emission and the emission-corrected resonant absorption increase with [O ii] λλ3727, 3730 rest equivalent width and luminosity, with a slightly larger dependence on the former. Our results show that the eBOSS and future dark-energy surveys (e.g., Dark Energy Spectroscopic

  2. Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Yoshihide, E-mail:; Nishimura, Yusaku F.; Suzuki, Ryo; Beniya, Atsushi; Isomura, Noritake [Toyota Central R& D Labs., Inc., Yokomichi 41-1, Nagakute, Aichi 480-1192 (Japan); Uehara, Hiromitsu; Asakura, Kiyotaka; Takakusagi, Satoru [Catalysis Research Center, Hokkaido University, Kita 21-10, Sapporo, Hokkaido 001-0021 (Japan); Nimura, Tomoyuki [AVC Co., Ltd., Inada 1450-6, Hitachinaka, Ibaraki 312-0061 (Japan)


    A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstrated by a successful PTRF-XAFS study of Pt{sub 4} clusters deposited on a TiO{sub 2}(110) surface.

  3. Woodson by Ultraviolet Spectroscopy

    Directory of Open Access Journals (Sweden)

    Patrícia M. S. S. Barros


    Full Text Available For the registration of phytomedicines and their availability to the population, National Agency of Sanitary Surveillance (ANVISA establishes quality, security, and efficacy parameters, stipulating control requirements similar to those applied to synthetic medicines. This work reports the investigation of the bark of Himatanthus lancifolius and its extracts aiming to contribute to the standardization of derivatives of this plant species. The developed quantification method shows high selectivity at 281nm, which confers confidence to the detection of the alkaloids. The method is robust, according to the current regulation, and shows linearity, precision, and accuracy, beside accessibility and simplicity in execute. The pH 10 alkaloid fraction obtained from the aqueous extract of the analyzed sample represents 0.219% in the dried extract. These results contribute for reducing the lack of methods for the quality control of phytomedicines prepared from H. lancifolius.

  4. Probing the influence of X-rays on aqueous copper solutions using time-resolved in situ combined video/X-ray absorption near-edge/ultraviolet-visible spectroscopy

    NARCIS (Netherlands)

    Mesu, J. Gerbrand; Beale, Andrew M.|info:eu-repo/dai/nl/325802068; de Groot, Frank M. F.|info:eu-repo/dai/nl/08747610X; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397


    Time-resolved in situ video monitoring and ultraviolet-visible spectroscopy in combination with X-ray absorption near-edge spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a

  5. Possible observation of parametrically amplified coherent phasons in K0.3MoO3 using time-resolved extreme-ultraviolet angle-resolved photoemission spectroscopy (United States)

    Liu, H. Y.; Gierz, I.; Petersen, J. C.; Kaiser, S.; Simoncig, A.; Cavalieri, A. L.; Cacho, C.; Turcu, I. C. E.; Springate, E.; Frassetto, F.; Poletto, L.; Dhesi, S. S.; Xu, Z.-A.; Cuk, T.; Merlin, R.; Cavalleri, A.


    We use time- and angle-resolved photoemission spectroscopy in the extreme ultraviolet to measure the time- and momentum-dependent electronic structures of photoexcited K0.3MoO3. Prompt depletion of the charge-density wave condensate launches coherent oscillations of the amplitude mode, observed as a 1.7-THz-frequency modulation of the bonding band position. In contrast, the antibonding band oscillates at about half this frequency. We attribute these oscillations to coherent excitation of phasons via parametric amplification of phase fluctuations.

  6. Clocking the Melting Transition of Charge and Lattice Order in 1T-TaS2 with Ultrafast Extreme-Ultraviolet Angle-Resolved Photoemission Spectroscopy (United States)

    Petersen, J. C.; Kaiser, S.; Dean, N.; Simoncig, A.; Liu, H. Y.; Cavalieri, A. L.; Cacho, C.; Turcu, I. C. E.; Springate, E.; Frassetto, F.; Poletto, L.; Dhesi, S. S.; Berger, H.; Cavalleri, A.


    We use time- and angle-resolved photoemission spectroscopy with sub-30-fs extreme-ultraviolet pulses to map the time- and momentum-dependent electronic structure of photoexcited 1T-TaS2. This compound is a two-dimensional Mott insulator with charge-density wave ordering. Charge order, evidenced by splitting between occupied subbands at the Brillouin zone boundary, melts well before the lattice responds. This challenges the view of a charge-density wave caused by electron-phonon coupling and Fermi-surface nesting alone, and suggests that electronic correlations play a key role in driving charge order.

  7. A vacuum double-crystal spectrometer for reference-free highly charged ions X-ray spectroscopy

    CERN Document Server

    Amaro, P; Schlesser, S; Gumberidze, Alexandre; Kessler, Ernest G; Henins, Albert; Bigot, E -O Le; Trassinelli, M; Isac, Jean-Michel; Travers, Pascal; Guerra, Mauro; Santos, J P; Indelicato, Paul


    We have built a vacuum double crystal spectrometer, which coupled to an electron-cyclotron resonance ion source, allows to measure low-energy x-ray transitions in highly-charged ions with accuracies of the order of a few parts per million. We describe in detail the instrument and its performances. Furthermore, we present a few spectra of transitions in Ar$^{14+}$, Ar$^{15+}$ and Ar$^{16+}$. We have developed an \\emph{ab initio} simulation code that allows us to obtain accurate line profiles. It can reproduce experimental spectra with unprecedented accuracy. The quality of the profiles allows the direct determination of line width.

  8. Determination of Degree of Ionization of Poly(allylamine hydrochloride) (PAH) and Poly[1-[4-(3-carboxy‑4 hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) in Layer-by-Layer Films using Vacuum Photoabsorption Spectroscopy

    DEFF Research Database (Denmark)

    Ferreira, Q; Gomes, Paulo J.; Ribeiro, Paulo A.


    Electrostatic and hydrophobic interactions govern most of the properties of supramolecular systems, which is the reason determining the degree of ionization of macromolecules has become crucial for many applications. In this paper, we show that high-resolution ultraviolet spectroscopy (VUV) can b...

  9. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces (United States)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Seiler, A.; Bondarchuk, O.; Hänsel-Ziegler, W.; Risse, T.; Freund, H.-J.


    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  10. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)


    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  11. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A


    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  12. Vacuum ultraviolet excited luminescence properties of Ca3Gd7(SiO4)5(PO4)O2:Re3+ (Re3+=Tb3+, Dy3+) phosphors (United States)

    Zhang, Feng; Wang, Yuhua; Huang, Yan; Tao, Ye


    A series of Ca3Gd7(SiO4)5(PO4)O2:Re3+ (Re3+=Tb3+, Dy3+) phosphors were synthesized by a solid-state reaction, and their vacuum ultraviolet excitation and emission characteristics were measured. All the excitation spectra show a broad band in the region of 140-210 nm, which can be mainly assigned to the host absorption. For Tb3+-doped sample, the absorption bands at 230 nm and 281 nm are respectively ascribed to the f-d spin-allowed and spin-forbidden transitions of Tb3+. In Dy3+-doped sample, the f-d spin-allowed transitions of Dy3+ and O2-→Dy3+ charge transfer band have not been clearly distinguished probably because of the overlapping with the strong host absorption band. The weak bands at 267 and 288 nm are attributed to be the f-d spin-forbidden transitions of Dy3+. The concentration dependence of the emission intensity upon the excitation at 172 nm indicates that the optimal doping concentrations of Tb3+ and Dy3+ are 11 mol% and 5 mol%, respectively. The optimal Tb3+ and Dy3+-activated samples respectively exhibit yellowish green and white emitting colors due to their characteristic emissions.

  13. Deciphering the structure of isomeric oligosaccharides in a complex mixture by tandem mass spectrometry: photon activation with vacuum ultra-violet brings unique information and enables definitive structure assignment. (United States)

    Ropartz, David; Lemoine, Jérôme; Giuliani, Alexandre; Bittebière, Yann; Enjalbert, Quentin; Antoine, Rodolphe; Dugourd, Philippe; Ralet, Marie-Christine; Rogniaux, Hélène


    Carbohydrates have a wide variety of structures whose complexity and heterogeneity challenge the field of analytical chemistry. Tandem mass spectrometry, with its remarkable sensitivity and high information content, provides key advantages to addressing the structural elucidation of polysaccharides. Yet, classical fragmentation by collision-activated dissociation (CAD) in many cases fails to reach a comprehensive structural determination, especially when isomers have to be differentiated. In this work, for the first time, vacuum ultra-violet (VUV) synchrotron radiation is used as the activation process in tandem mass spectrometry of large oligosaccharides. Compared to low energy CAD (LE-CAD), photon activated dissociation brought more straightforward and valuable structural information. The outstanding feature was that complete series of informative ions were produced, with only minor neutral losses. Moreover, systematic fragmentation rules could be drawn thus facilitating the definitive assignments of fragment identities. As a result, most of the structures present in a complex mixture of oligogalacturonans could be comprehensively resolved, including many isomers differing in the position of methyl groups along the galacturonic acid backbone. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  14. Comparison of vacuum ultra-violet emission of Ar/CF4 and Ar/CF3I capacitively coupled plasmas (United States)

    Zotovich, A.; Proshina, O.; el Otell, Z.; Lopaev, D.; Rakhimova, T.; Rakhimov, A.; de Marneffe, J.-F.; Baklanov, M. R.


    Spectra in the vacuum-ultra violet range (VUV, 30 nm-200 nm) as well as in the ultra-violet(UV) and visible ranges (UV+vis, 200 nm-800 nm) were measured from Ar/CF3I and Ar/CF4 discharges. The discharges were generated in an industrial 300 mm capacitively coupled plasma source with 27 MHz radio-frequency power. It was seen that the measured spectra were strongly modified. This is mainly due to absorption, especially by CF3I, and Ar self-trapping along the line of sight, towards the detector and in the plasma itself. The estimated unabsorbed VUV spectra were revealed from the spectra of mixtures with low fluorocarbon gas content by means of normalization with unabsorbed I* emission, at 206 nm, and CF2\\ast band (1B1(0,v‧,0){{\\to}1} A1(0,{{\\text{v}}\\prime \\prime} ,0)) emission between 230 nm and 430 nm. Absolute fluences of UV CF2\\ast emission were derived using hybrid 1-dimensional (1D) particle-in-cell (PIC) Monte-Carlo (MC) model calculations. Absolute calibration of the VUV emission was performed using these calculated values from the model, which has never been done previously for real etch conditions in an industrial chamber. It was seen that the argon resonant lines play a significant role in the VUV spectra. These lines are dominant in the case of etching recipes close to the standard ones. The restored unabsorbed spectra confirm that replacement of conventional CF4 etchant gas with CF3I in low-k etching recipes leads to an increase in the overall VUV emission intensity. However, emission from Ar exhibited the most intense peaks. Damage to low-k SiCOH glasses by the estimated VUV was calculated for blanket samples with pristine k-value of 2.2. The calculations were then compared with Fourier transform infrared (FTIR) data for samples exposed to the similar experimental conditions in the same reactor. It was shown that Ar emission plays the most significant role in VUV-induced damage.

  15. Simultaneous Real-Time Analysis of Bulk and Bottom Cure of Ultraviolet-Curable Inks Using Fourier Transform Infrared Spectroscopy. (United States)

    Boonen, Hennie A L; Koskamp, Janou A; Theiss, Wolfgang; Iedema, Piet D; Willemse, Robin X E


    The curing characteristics of an ultraviolet (UV) ink layer are of utmost importance for the development of UV inks. Measuring either bulk or bottom cure in itself is not new and has been the subject of many articles. In this article, two methods are described based on Fourier transform infrared (FT-IR) spectrometry to measure in real time and simultaneously the bulk and bottom cure of a thin UV ink layer. The procedure consists of applying a thin (10-12 µm) layer of UV-curing ink on an attenuated total reflection (ATR) crystal. The bottom cure is measured with ATR. The bulk cure is measured simultaneously with a reflection analysis (method 1) or a transmission analysis (method 2). With both methods, the bulk and bottom cure can be determined. To overcome problems with the interference in the ATR reflection setup, it is recommended to use the ATR transmission setup.

  16. Cavity ring-down spectroscopy for detection in liquid chromatography: Extension to tunable sources and ultraviolet wavelengths

    NARCIS (Netherlands)

    van der Sneppen, L.; Wiskerke, A.E.; Ariese, F.; Gooijer, C.; Ubachs, W.M.G.


    In earlier studies, it was demonstrated that the sensitivity of absorbance detection in liquid chromatography (LC) can be improved significantly by using cavity ring-down spectroscopy (CRDS). Thus far, CRDS experiments have been performed using visible laser light at fixed standard wavelengths, such

  17. Effect of the solvent on the size of clay nanoparticles in solution as determined using an ultraviolet-visible (UV-Vis) spectroscopy methodology. (United States)

    Alin, Jonas; Rubino, Maria; Auras, Rafael


    Ultraviolet-visible (UV-Vis) spectroscopy methodology was developed and utilized for the in situ nanoscale measurement of the size of mineral clay agglomerates in various liquid suspensions. The clays studied were organomodified and unmodified montmorillonite clays (I.44p, Cloisite 93a, and PGN). The methodology was compared and validated against dynamic light scattering (DLS) analysis. The method was able to measure clay agglomerates in solvents in situations where DLS analysis was unsuccessful due to the shapes, polydispersity, and high aspect ratios of the clay particles and the complexity of the aggregates, or dispersion medium. The measured clay agglomerates in suspension were found to be in the nanometer range in the more compatible solvents, and their sizes correlated with the Hansen solubility parameter space distance between the clay modifiers and the solvents. Mass detection limits for size determination were in the range from 1 to 9 mg/L. The methodology thus provides simple, rapid, and inexpensive characterization of clays or particles in the nano- or microsize range in low concentrations in various liquid media, including complex mixtures or highly viscous fluids that are difficult to analyze with DLS. In addition, by combining UV-VIS spectroscopy with DLS it was possible to discern flocculation behavior in liquids, which otherwise could result in false size measurements by DLS alone.

  18. Temperature-dependent Raman and ultraviolet photoelectron spectroscopy studies on phase transition behavior of VO{sub 2} films with M1 and M2 phases

    Energy Technology Data Exchange (ETDEWEB)

    Okimura, Kunio, E-mail:; Hanis Azhan, Nurul [Graduate School of Engineering, Tokai University, Hiratsuka 259-1292 (Japan); Hajiri, Tetsuya [UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Kimura, Shin-ichi [UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871 (Japan); Zaghrioui, Mustapha; Sakai, Joe [GREMAN, UMR 7347 CNRS, Université François Rabelais de Tours, Parc de Grandmont, 37200 Tours (France)


    Structural and electronic phase transitions behavior of two polycrystalline VO{sub 2} films, one with pure M1 phase and the other with pure M2 phase at room temperature, were investigated by temperature-controlled Raman spectroscopy and ultraviolet photoelectron spectroscopy (UPS). We observed characteristic transient dynamics in which the Raman modes at 195 cm{sup −1} (V-V vibration) and 616 cm{sup −1} (V-O vibration) showed remarkable hardening along the temperature in M1 phase film, indicating the rearrangements of V-V pairs and VO{sub 6} octahedra. It was also shown that the M1 Raman mode frequency approached those of invariant M2 peaks before entering rutile phase. In UPS spectra with high energy resolution of 0.03 eV for the M2 phase film, narrower V{sub 3d} band was observed together with smaller gap compared to those of M1 phase film, supporting the nature of Mott insulator of M2 phase even in the polycrystalline film. Cooperative behavior of lattice rearrangements and electronic phase transition was suggested for M1 phase film.

  19. Proposal for Testing and Validation of Vacuum Ultra-Violet Atomic Laser-Induced Fluorescence as a Method to Analyze Carbon Grid Erosion in Ion Thrusters (United States)

    Stevens, Richard


    Previous investigation under award NAG3-25 10 sought to determine the best method of LIF to determine the carbon density in a thruster plume. Initial reports from other groups were ambiguous as to the number of carbon clusters that might be present in the plume of a thruster. Carbon clusters would certainly affect the ability to LIF; if they were the dominant species, then perhaps the LIF method should target clusters. The results of quadrupole mass spectroscopy on sputtered carbon determined that minimal numbers of clusters were sputtered from graphite under impact from keV Krypton. There were some investigations in the keV range by other groups that hinted at clusters, but at the time the proposal was presented to NASA, there was no data from low-energy sputtering available. Thus, the proposal sought to develop a method to characterize the population only of atoms sputtered from a graphite target in a test cell. Most of the ground work had been established by the previous two years of investigation. The proposal covering 2003 sought to develop an anti-Stokes Raman shifting cell to generate VUW light and test this cell on two different laser systems, ArF and YAG- pumped dye. The second goal was to measure the lowest detectable amounts of carbon atoms by 156.1 nm and 165.7 nm LIF. If equipment was functioning properly, it was expected that these goals would be met easily during the timeframe of the proposal, and that is the reason only modest funding was requested. The PI was only funded at half- time by Glenn during the summer months. All other work time was paid for by Whitworth College. The college also funded a student, Charles Shawley, who worked on the project during the spring.

  20. Vacuum extraction

    DEFF Research Database (Denmark)

    Maagaard, Mathilde; Oestergaard, Jeanett; Johansen, Marianne


    Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validationof the developed OSATS scale for vacuum...

  1. Analysis of pure tar substances (polycyclic aromatic hydrocarbons) in the gas stream using ultraviolet visible (UV-Vis) spectroscopy and multivariate curve resolution (MCR). (United States)

    Weide, Tobias; Guschin, Viktor; Becker, Wolfgang; Koelle, Sabine; Maier, Simon; Seidelt, Stephan


    The analysis of tar, mostly characterized as polycyclic aromatic hydrocarbons (PAHs), describes a topic that has been researched for years. An online analysis of tar in the gas stream in particular is needed to characterize the tar conversion or formation in the biomass gasification process. The online analysis in the gas is carried out with ultraviolet-visible (UV-Vis) spectroscopy (190-720 nm). This online analysis is performed with a measuring cell developed by the Fraunhofer Institute for Chemical Technology (ICT). To this day, online tar measurements using UV-Vis spectroscopy have not been carried out in detail. Therefore, PAHs are analyzed as follows. The measurements are split into different steps. The first step to prove the online method is to vaporize single tar substances. These experiments show that a qualitative analysis of PAHs in the gas stream with the used measurement setup is possible. Furthermore, it is shown that the method provides very exact results, so that a differentiation of various PAHs is possible. The next step is to vaporize a PAH mixture. This step consists of vaporizing five pure substances almost simultaneously. The interpretation of the resulting data is made using a chemometric interpretation method, the multivariate curve resolution (MCR). The verification of the calculated results is the main aim of this experiment. It has been shown that the tar mixture can be analyzed qualitatively and quantitatively (in arbitrary units) in detail using the MCR. Finally it is the main goal of this paper to show the first steps in the applicability of the UV-Vis spectroscopy and the measurement setup on online tar analysis in view of characterizing the biomass gasification process. Due to that, the gasification plant (at the laboratory scale), developed and constructed by the Fraunhofer ICT, has been used to vaporize these substances. Using this gasification plant for the experiments enables the usage of the measurement setup also for the

  2. Rapid measurement of methyl cellulose precipitable tannins using ultraviolet spectroscopy with chemometrics: application to red wine and inter-laboratory calibration transfer. (United States)

    Dambergs, Robert G; Mercurio, Meagan D; Kassara, Stella; Cozzolino, Daniel; Smith, Paul A


    Information relating to tannin concentration in grapes and wine is not currently available simply and rapidly enough to inform decision-making by grape growers, winemakers, and wine researchers. Spectroscopy and chemometrics have been implemented for the analysis of critical grape and wine parameters and offer a possible solution for rapid tannin analysis. We report here the development and validation of an ultraviolet (UV) spectral calibration for the prediction of tannin concentration in red wines. Such spectral calibrations reduce the time and resource requirements involved in measuring tannins. A diverse calibration set (n = 204) was prepared with samples of Australian wines of five varieties (Cabernet Sauvignon, Shiraz, Merlot, Pinot Noir, and Durif), from regions spanning the wine grape growing areas of Australia, with varying climate and soils, and with vintages ranging from 1991 to 2007. The relationship between tannin measured by the methyl cellulose precipitation (MCP) reference method at 280 nm and tannin predicted with a multiple linear regression (MLR) calibration, using ultraviolet (UV) absorbance at 250, 270, 280, 290, and 315 nm, was strong (r(2)val = 0.92; SECV = 0.20 g/L). An independent validation set (n = 85) was predicted using the MLR algorithm developed with the calibration set and gave confidence in the ability to predict new samples, independent of the samples used to prepare the calibration (r(2)val = 0.94; SEP = 0.18 g/L). The MLR algorithm could also predict tannin in fermenting wines (r(2)val = 0.76; SEP = 0.18 g/L), but worked best from the second day of ferment on. This study also explored instrument-to-instrument transfer of a spectral calibration for MCP tannin. After slope and bias adjustments of the calibration, efficient calibration transfer to other laboratories was clearly demonstrated, with all instruments in the study effectively giving identical results on a transfer set.

  3. Vacuum induced photoresist outgassing (United States)

    Waterman, Justin; Mbanaso, Chimaobi; Denbeaux, Gregory


    In order to continue the trend toward smaller feature sizes in lithography, new methods of lithography will be needed. A likely method for printing features 32 nm and smaller is extreme ultraviolet (EUV) lithography. EUV allows for features to be printed that are smaller than the current methods can achieve. However, outgassing of the photoresist is a concern for EUV lithography. The outgassed components can lead to contamination of the optics, degrading the reflectivity and hence lowering throughput of the exposure tools. Outgassing due to EUV exposure has been investigated by many groups. However, there were no complete investigations available of vacuum induced outgassing. In this paper, several methods were employed to investigate the outgassing due to vacuum. It was found that the vacuum induced outgassing outgassed a similar number of molecules as the outgassing due to EUV exposure. Furthermore, almost all of the outgassing was completed after about two minutes in vacuum. To mitigate the potential concern of outgassing due to vacuum causing contamination of optics, this work shows that photoresist coated silicon wafers only require about two minutes of pumping prior to insertion near the optics within EUV lithography tools.

  4. Experimental determination of vacuum-level band alignments of SnS-based solar cells by photoelectron yield spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Mutsumi, E-mail:; Shimizu, Tsubasa; Kawade, Daisuke [Department of Electrical Engineering, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda 278-8510 (Japan); Ramya, Kottadi; Ramakrishna Reddy, K. T. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)


    Energy band offsets of SnS-based solar cell structure using various n-type semiconductors, such as CdS, SnS{sub 2}, In{sub 2}S{sub 3}, ZnIn{sub 2}Se{sub 4}, ZnO, and Mg{sub 0.3}In{sub 0.7}O, are evaluated by photoelectron yield spectroscopy. The valence band discontinuities are estimated to be 1.6 eV for both SnS/CdS and SnS/SnS{sub 2}, 0.9 eV for SnS/In{sub 2}S{sub 3}, 1.7 eV for SnS/ZnIn{sub 2}Se{sub 4}, and 1.8 eV for both SnS/ZnO and SnS/Mg{sub 0.3}Zn{sub 0.7}O. Using the valence band discontinuity values and the corresponding energy bandgaps of the layers, energy band diagrams are developed. This study implied a type-I heterostructure, appropriate for SnS-based solar cell, for the ZnIn{sub 2}Se{sub 4} or Mg{sub x}Zn{sub 1−x}O (0 ≤ x ≤ 0.3) interface and type-II for other junctions.

  5. Experimental determination of vacuum-level band alignments of SnS-based solar cells by photoelectron yield spectroscopy (United States)

    Sugiyama, Mutsumi; Shimizu, Tsubasa; Kawade, Daisuke; Ramya, Kottadi; Ramakrishna Reddy, K. T.


    Energy band offsets of SnS-based solar cell structure using various n-type semiconductors, such as CdS, SnS2, In2S3, ZnIn2Se4, ZnO, and Mg0.3In0.7O, are evaluated by photoelectron yield spectroscopy. The valence band discontinuities are estimated to be 1.6 eV for both SnS/CdS and SnS/SnS2, 0.9 eV for SnS/In2S3, 1.7 eV for SnS/ZnIn2Se4, and 1.8 eV for both SnS/ZnO and SnS/Mg0.3Zn0.7O. Using the valence band discontinuity values and the corresponding energy bandgaps of the layers, energy band diagrams are developed. This study implied a type-I heterostructure, appropriate for SnS-based solar cell, for the ZnIn2Se4 or MgxZn1-xO (0 ≤ x ≤ 0.3) interface and type-II for other junctions.

  6. Ultra high vacuum high precision low background setup with temperature control for thermal desorption mass spectroscopy (TDA-MS) of hydrogen in metals. (United States)

    Merzlikin, Sergiy V; Borodin, S; Vogel, D; Rohwerder, M


    In this work, a newly developed UHV-based high precision low background setup for hydrogen thermal desorption analysis (TDA) of metallic samples is presented. Using an infrared heating with a low thermal capacity enables a precise control of the temperature and rapid cool down of the measurement chamber. This novel TDA-set up is superior in sensitivity to almost every standard hydrogen analyzer available commercially due to the special design of the measurement chamber, resulting in a very low hydrogen background. No effects of background drift characteristic as for carrier gas based TDA instruments were observed, ensuring linearity and reproducibility of the analysis. This setup will prove to be valuable for detailed investigations of hydrogen trapping sites in steels and other alloys. With a determined limit of detection of 5.9×10(-3)µg g(-1) hydrogen the developed instrument is able to determine extremely low hydrogen amounts even at very low hydrogen desorption rates. This work clearly demonstrates the great potential of ultra-high vacuum thermal desorption mass spectroscopy instrumentation. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. On-line monitoring of vacuum drying of theophylline using NIR spectroscopy: solid-state transitions, water content and semi-empirical modeling. (United States)

    Amira, Touil; Roman, Peczalski; Fethi, Zagrouba


    The aim of this work was to monitor in-line and at a real time, the solid-state forms during pharmaceuticals manufacturing. It concerns the dehydration behavior and the solid-state transitions of theophylline in an agitated vacuum contact dryer. First, a near infrared spectroscopy (NIRS) method was performed using a reflectance diffuse probe to measure the in-line and in-situ exact composition of the mixture of different forms of theophylline and water content during drying. A multivariate modeling has been investigated to build a robust model which can predict four components at the same time during drying process. The XRPD analysis was used as a reference method in the process of calibration of NIRS. The indicators of the accuracy in quantitative spectral analysis confirm the robustness of the model and the efficiency of the method of calibration. Second, the kinetics of solid state transformations were investigated. It was shown that the dehydration advanced first by the formation of the metastable anhydrate and after a lag time of the stable one. Once the stable form appeared, formation of the metastable form came to an end. The temperature was found out to be the main factor controlling the overall process rate but also the final contents of the stable and metastable anhydrates for the considered dryer and operating conditions range. Finally, a semi-empirical drying model was proposed and significant quantitative differences were found, particularly at the product temperature which was probably caused by the excessive simplicity of the model.

  8. A green analytical method for the simultaneous analysis of cefixime trihydrate and ambroxol HCl based on ultraviolet derivative spectroscopy

    Directory of Open Access Journals (Sweden)

    Ceema Mathew


    Full Text Available Context: Until date, there is no reported derivative spectrophotometric method for the combination of cefixime trihydrate (CEF and ambroxol HCl (ABH. So an urgent need was felt to develop an ultraviolet (UV derivative spectroscopic method, which reduces the cost of analysis on comparing with high-performance liquid chromatography or high-performance thin layer chromatography method. Aims: To develop and validate an economical and ecofriendly derivative spectroscopic method that avoids the use of organic solvents for simultaneous quantification of both the drugs. Materials and Methods: A simple method based on the derivative spectrophotometric method at zero crossing wavelengths has been developed for the simultaneous quantification of CEF and ABH. As the method depends on hydrotropic dissolution, 0.1N urea is used as the solvent, and it yields an economical and ecofriendly method. Two wavelengths 253 nm (zero crossing point (ZCP for CEF and 306 nm (ZCP for ABH were selected for the quantification of ABH and CEF respectively. Results: The first derivative amplitude-concentration plots were linear over the range of 5-35 μg/ml and 3-10.5 μg/ml with detection limits of 0.187 and 0.0937 μg/ml and quantification limits of 0.625 and 0.312 μg/ml for CEF and ABH respectively. The percentage recovery was within the range between 99.05% and 102%. The % relative standard deviation for precision and accuracy of the method was found to be <2%. Conclusion: The proposed method was found to be simple, accurate and precise and can be successfully applied to the routine quality control analysis of studied drugs in their tablet formulations.

  9. Far-ultraviolet Spectroscopy of Recent Comets with the Cosmic Origins Spectrograph on the Hubble Space Telescope (United States)

    Feldman, Paul D.; Weaver, Harold A.; A'Hearn, Michael F.; Combi, Michael R.; Dello Russo, Neil


    Since its launch in 1990, the Hubble Space Telescope (HST) has served as a platform with unique capabilities for remote observations of comets. Successive generations of imagers and spectrographs have seen large advances in sensitivity and spectral resolution enabling observations of the diverse properties of a representative number of comets during the past 25 years. To date, four comets have been observed in the far-ultraviolet by the Cosmic Origins Spectrograph (COS), the last spectrograph to be installed in HST, in 2009: 103P/Hartley 2, C/2009 P1 (Garradd), C/2012 S1 (ISON), and C/2014 Q2 (Lovejoy). COS has unprecedented sensitivity, albeit no spatial resolution, and the principal objective was to determine the relative CO abundance from measurements of the CO Fourth Positive system in the spectral range of 1400 to 1700 Å. In the two brightest comets, nineteen bands of this system were clearly identified. The water production rate was derived from nearly simultaneous observations of the OH (0,0) band at 3085 Å by the Space Telescope Imaging Spectrograph (STIS). The derived CO/H2O production rate ratio ranged from ~0.3% for Hartley 2 (Weaver et al., ApJ 734:L5, 2011) to ~20% for Garradd. In addition, strong partially resolved emission features due to multiplets of S I, centered at 1429 Å and 1479 Å, and of C I at 1561 Å and 1657 Å, were observed in all four comets. Weak emission from several lines of the H2 Lyman band system, excited by solar Lyman-α and Lyman-β pumped fluorescence, were detected in comet Lovejoy.This work is based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Support was provided by NASA through grants from the Space Telescope Science Institute.

  10. Hubble space telescope near-ultraviolet spectroscopy of the bright cemp-no star BD+44°493

    Energy Technology Data Exchange (ETDEWEB)

    Placco, Vinicius M. [Gemini Observatory, Hilo, HI 96720 (United States); Beers, Timothy C.; Smith, Verne V. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Roederer, Ian U. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Cowan, John J. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Frebel, Anna [Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Filler, Dan; Ivans, Inese I. [Department of Physics and Astronomy, The University of Utah, Salt Lake City, UT 84112 (United States); Lawler, James E. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Schatz, Hendrik [JINA—Joint Institute for Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556-5670 (United States); Sneden, Christopher [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Sobeck, Jennifer S. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Aoki, Wako, E-mail: [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)


    We present an elemental-abundance analysis, in the near-ultraviolet (NUV) spectral range, for the extremely metal-poor star BD+44°493 a ninth magnitude subgiant with [Fe/H] =–3.8 and enhanced carbon, based on data acquired with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. This star is the brightest example of a class of objects that, unlike the great majority of carbon-enhanced metal-poor (CEMP) stars, does not exhibit over-abundances of heavy neutron-capture elements (CEMP-no). In this paper, we validate the abundance determinations for a number of species that were previously studied in the optical region, and obtain strong upper limits for beryllium and boron, as well as for neutron-capture elements from zirconium to platinum, many of which are not accessible from ground-based spectra. The boron upper limit we obtain for BD+44°493, log ε (B) <–0.70, the first such measurement for a CEMP star, is the lowest yet found for very and extremely metal-poor stars. In addition, we obtain even lower upper limits on the abundances of beryllium, log ε (Be) <–2.3, and lead, log ε (Pb) <–0.23 ([Pb/Fe] <+1.90), than those reported by previous analyses in the optical range. Taken together with the previously measured low abundance of lithium, the very low upper limits on Be and B suggest that BD+44°493 was formed at a very early time, and that it could well be a bona-fide second-generation star. Finally, the Pb upper limit strengthens the argument for non-s-process production of the heavy-element abundance patterns in CEMP-no stars.

  11. Ultraviolet Waves (United States)

    Molde, Trevor


    Outlines the discovery and nature of ultraviolet light, discusses some applications for these wavelengths, and describes a number of experiments with ultraviolet radiation suitable for secondary school science classes. (JR)

  12. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal


    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  13. Spectroscopy

    CERN Document Server

    Walker, S


    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  14. Plant sunscreens in the UV-B: ultraviolet spectroscopy of jet-cooled sinapoyl malate, sinapic acid, and sinapate ester derivatives. (United States)

    Dean, Jacob C; Kusaka, Ryoji; Walsh, Patrick S; Allais, Florent; Zwier, Timothy S


    Ultraviolet spectroscopy of sinapoyl malate, an essential UV-B screening agent in plants, was carried out in the cold, isolated environment of a supersonic expansion to explore its intrinsic UV spectral properties in detail. Despite these conditions, sinapoyl malate displays anomalous spectral broadening extending well over 1000 cm(-1) in the UV-B region, presenting the tantalizing prospect that nature's selection of UV-B sunscreen is based in part on the inherent quantum mechanical features of its excited states. Jet-cooling provides an ideal setting in which to explore this topic, where complications from intermolecular interactions are eliminated. In order to better understand the structural causes of this behavior, the UV spectroscopy of a series of sinapate esters was undertaken and compared with ab initio calculations, starting with the simplest sinapate chromophore sinapic acid, and building up the ester side chain to sinapoyl malate. This "deconstruction" approach provided insight into the active mechanism intrinsic to sinapoyl malate, which is tentatively attributed to mixing of the bright V ((1)ππ*) state with an adiabatically lower (1)nπ* state which, according to calculations, shows unique charge-transfer characteristics brought on by the electron-rich malate side chain. All members of the series absorb strongly in the UV-B region, but significant differences emerge in the appearance of the spectrum among the series, with derivatives most closely associated with sinapoyl malate showing characteristic broadening even under jet-cooled conditions. The long vibronic progressions, conformational distribution, and large oscillator strength of the V (ππ*) transition in sinapates makes them ideal candidates for their role as UV-B screening agents in plants.

  15. Nondestructive identification of dye mixtures in polyester and cotton fibers using raman spectroscopy and ultraviolet-visible (UV-Vis) microspectrophotometry. (United States)

    Was-Gubala, Jolanta; Starczak, Roza


    Presented in this paper is an assessment of the applicability of Raman spectroscopy and microspectrophotometry (MSP) in visible and ultraviolet light (UV-Vis) in the examination of textile fibers dyed with mixtures of synthetic dyes. Fragments of single polyester fibers, stained with ternary mixtures of disperse dyes in small mass concentrations, and fragments of single cotton fibers, dyed with binary or ternary mixtures of reactive dyes, were subjected to the study. Three types of excitation sources, 514, 633, and 785 nm, were used during Raman examinations, while the MSP study was conducted in the 200 to 800 nm range. The results indicate that the capabilities for discernment of dye mixtures are similar in the spectroscopic methods that were employed. Both methods have a limited capacity to distinguish slightly dyed polyester fiber; additionally, it was found that Raman spectroscopy enables identification of primarily the major components in dye mixtures. The best results, in terms of the quality of Raman spectra, were obtained using an excitation source from the near infrared. MSP studies led to the conclusion that polyester testing should be carried out in the range above 310 nm, while for cotton fibers there is no limitation or restriction of the applied range. Also, MSP UV-Vis showed limited possibilities for discriminatory analysis of cotton fibers dyed with a mixture of reactive dyes, where the ratio of the concentration of the main dye used in the dyeing process to minor dye was higher than four. The results presented have practical applications in forensic studies, inter alia.

  16. Two-dimensional Fourier transform spectroscopy in the ultraviolet with sub-20 fs pump pulses and 250-720 nm supercontinuum probe (United States)

    Krebs, N.; Pugliesi, I.; Hauer, J.; Riedle, E.


    Experimental realizations of two-dimensional (2D) electronic spectroscopy in the ultraviolet (UV) must so far contend with a limited bandwidth in both the excitation and particularly the probe frequency. The pump bandwidth is at best 1500 cm-1 (full width at half maximum) at a fixed wavelength of 267 nm or 400 cm-1 for tunable pulses. The use of a replica of the pump pulse as a probe limits the observation of photochemical processes to the excitation region and makes the disentanglement of overlapping signal contributions difficult. We show that 2D Fourier transform spectroscopy can be conducted in a shaper-assisted collinear setup comprising fully tunable UV pulse pairs and supercontinuum probe spanning 250-720 nm. The pump pulses are broadened up to a useable spectral coverage of 2000 cm-1 (25 nm at 316 nm) by self-phase modulation in bulk CaF2 and compressed to 18 fs. By referencing the white light probe and eliminating pump stray light contributions, high signal-to-noise ratios even for weak probe intensities are achieved. Data acquisition times as short as 4 min for a selected population time allow the rapid recording of 2D spectra for photolabile biological samples even with the employed 1 kHz laser system. The potential of the setup is demonstrated on two representative molecules: pyrene and 2,2-diphenyl-5,6-benzo(2H)chromene. Well-resolved cross-peaks are observed and the excitation energy dependence of the relaxation processes is revealed.

  17. Low-cost 3D printed 1  nm resolution smartphone sensor-based spectrometer: instrument design and application in ultraviolet spectroscopy. (United States)

    Wilkes, Thomas C; McGonigle, Andrew J S; Willmott, Jon R; Pering, Tom D; Cook, Joseph M


    We report on the development of a low-cost spectrometer, based on off-the-shelf optical components, a 3D printed housing, and a modified Raspberry Pi camera module. With a bandwidth and spectral resolution of ≈60  nm and 1 nm, respectively, this device was designed for ultraviolet (UV) remote sensing of atmospheric sulphur dioxide (SO 2 ), ≈310  nm. To the best of our knowledge, this is the first report of both a UV spectrometer and a nanometer resolution spectrometer based on smartphone sensor technology. The device performance was assessed and validated by measuring column amounts of SO 2 within quartz cells with a differential optical absorption spectroscopy processing routine. This system could easily be reconfigured to cover other UV-visible-near-infrared spectral regions, as well as alternate spectral ranges and/or linewidths. Hence, our intention is also to highlight how this framework could be applied to build bespoke, low-cost, spectrometers for a range of scientific applications.

  18. Real-time monitoring of benzene, toluene, and p-xylene in a photoreaction chamber with a tunable mid-infrared laser and ultraviolet differential optical absorption spectroscopy. (United States)

    Parsons, Matthew T; Sydoryk, Ihor; Lim, Alan; McIntyre, Thomas J; Tulip, John; Jäger, Wolfgang; McDonald, Karen


    We describe the implementation of a mid-infrared laser-based trace gas sensor with a photoreaction chamber, used for reproducing chemical transformations of benzene, toluene, and p-xylene (BTX) gases that may occur in the atmosphere. The system performance was assessed in the presence of photoreaction products including aerosol particles. A mid-infrared external cavity quantum cascade laser (EC-QCL)-tunable from 9.41-9.88 μm (1012-1063 cm(-1))-was used to monitor gas phase concentrations of BTX simultaneously and in real time during chemical processing of these compounds with hydroxyl radicals in a photoreaction chamber. Results are compared to concurrent measurements using ultraviolet differential optical absorption spectroscopy (UV DOAS). The EC-QCL based system provides quantitation limits of approximately 200, 200, and 600 parts in 10(9) (ppb) for benzene, toluene, and p-xylene, respectively, which represents a significant improvement over our previous work with this laser system. Correspondingly, we observe the best agreement between the EC-QCL measurements and the UV DOAS measurements with benzene, followed by toluene, then p-xylene. Although BTX gas-detection limits are not as low for the EC-QCL system as for UV DOAS, an unidentified by-product of the photoreactions was observed with the EC-QCL, but not with the UV DOAS system.

  19. VACUUM TRAP (United States)

    Gordon, H.S.


    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  20. Evolution of Oxygen Deficiency Center on Fused Silica Surface Irradiated by Ultraviolet Laser and Posttreatment

    Directory of Open Access Journals (Sweden)

    Hai-Bing Lü


    Full Text Available Evolution of oxygen deficiency centers (ODCs on a fused silica surface irradiated using a 355 nm ultraviolet (UV laser beam in both vacuum and atmospheric conditions was quantitatively studied using photoluminescence and X-ray photoelectron spectroscopy. When the fusedsilica surface was exposed to the UV laser in vacuum, the laser damage threshold was decreased whereas the concentration of the ODCs was increased. For the fuse silica operated under the high power lasers, creation of ODCs on their surface resulted from the UV laser irradiation, and this is more severe in a high vacuum. The laser fluence and/or laser intensity have significant effects on the increase of the ODCs concentration. The ODCs can be effectively repaired using postoxygen plasma treatment and UV laser irradiation in an excessive oxygen environment. Results also demonstrated that the “gain” and “loss” of oxygen at the silica surface is a reversible and dynamic process.

  1. Ultraviolet (UV) Raman Spectroscopy Study of the Soret Effect in High-Pressure CO2-Water Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; Maupin, Gary D.; McGrail, B. Peter


    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O or D2O subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O, at 10 MPa and temperatures near the critical point of CO2, had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19 C. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for D2O were too weak to measure with confidence even at the limit of D2O solubility.

  2. Vacuum Technology

    Energy Technology Data Exchange (ETDEWEB)

    Biltoft, P J


    The environmental condition called vacuum is created any time the pressure of a gas is reduced compared to atmospheric pressure. On earth we typically create a vacuum by connecting a pump capable of moving gas to a relatively leak free vessel. Through operation of the gas pump the number of gas molecules per unit volume is decreased within the vessel. As soon as one creates a vacuum natural forces (in this case entropy) work to restore equilibrium pressure; the practical effect of this is that gas molecules attempt to enter the evacuated space by any means possible. It is useful to think of vacuum in terms of a gas at a pressure below atmospheric pressure. In even the best vacuum vessels ever created there are approximately 3,500,000 molecules of gas per cubic meter of volume remaining inside the vessel. The lowest pressure environment known is in interstellar space where there are approximately four molecules of gas per cubic meter. Researchers are currently developing vacuum technology components (pumps, gauges, valves, etc.) using micro electro mechanical systems (MEMS) technology. Miniature vacuum components and systems will open the possibility for significant savings in energy cost and will open the doors to advances in electronics, manufacturing and semiconductor fabrication. In conclusion, an understanding of the basic principles of vacuum technology as presented in this summary is essential for the successful execution of all projects that involve vacuum technology. Using the principles described above, a practitioner of vacuum technology can design a vacuum system that will achieve the project requirements.

  3. Bright Linearly and Circularly Polarized Extreme Ultraviolet and Soft X-ray High Harmonics for Absorption Spectroscopy (United States)

    Fan, Tingting

    High harmonic generation (HHG) is an extreme nonlinear optical process. When implemented in a phase-matched geometry, HHG coherent upconverts femtosecond laser light into coherent "X-ray laser" beams, while retaining excellent spatial and temporal coherence, as well as the polarization state of the driving laser. HHG has a tabletop footprint, with femtosecond to attosecond time resolution, combined with nanometer spatial resolution. As a consequence of these unique capabilities, HHG is now being widely adopted for use in molecular spectroscopy and imaging, materials science, as well as nanoimaging in general. In the first half of this thesis, I demonstrate high flux linearly polarized soft X-ray HHG, driven by a single-stage 10-mJ Ti:sapphire regenerative amplifier at a repetition rate of 1 kHz. I first down-converted the laser to 1.3 mum using an optical parametric amplifier, before up-converting it into the soft X-ray region using HHG in a high-pressure, phase-matched, hollow waveguide geometry. The resulting optimally phase-matched broadband spectrum extends to 200 eV, with a soft X-ray photon flux of > 106 photons/pulse/1% bandwidth at 1 kHz, corresponding to > 109 photons/s/1% bandwidth, or approximately a three orders-of-magnitude increase compared with past work. Using this broad bandwidth X-ray source, I demonstrated X-ray absorption spectroscopy of multiple elements and transitions in molecules in a single spectrum, with a spectral resolution of 0.25 eV, and with the ability to resolve the near edge fine structure. In the second half of this thesis, I discuss how to generate the first bright circularly polarized (CP) soft X-ray HHG and also use them to implement the first tabletop X-ray magnetic circular dichroism (XMCD) measurements. Using counter-rotating CP lasers at 1.3 mum and 0.79 mum, I generated CPHHG with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right CP peaks, with energies

  4. Vacuum mechatronics (United States)

    Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo


    The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

  5. Ultraviolet emission properties of ZnO film with zinc deficiency by SS CVD (United States)

    Dai, Liping; Deng, Hong; Chen, Geng; Chen, Jinju


    A- b axis orientation ZnO film on silicon (1 0 0) substrate has been prepared by a single source chemical vapor deposition technique. X-ray photoelectron spectroscopy results revealed that the film was very close to stoichiometry but with a small amount of zinc deficiency. Temperature-dependent (10-300 K) ultraviolet photoluminescence of the film was presented. Comparing the photon energy separation of the several groups in the near band edge ultraviolet luminescence bands, as well as the variation of the relative intensities and the shift of the luminescence lines at different temperatures, free-, bound-exciton and its assisted phonon emission were observed, which corresponded to the mechanism of the ultraviolet emission properties. A strong ultraviolet emission resulting from the recombination of free-exciton was observed at 300 K photoluminescence spectrum examined in atmosphere environment. Contrasted to the relatively weak ultraviolet emission of the film in vacuum, atmosphere environment was found to be an important contribution to the strong ultraviolet emission of the film.

  6. State-to-state vacuum ultraviolet photodissociation study of CO2 on the formation of state-correlated CO(X1Σ+; V) with O(1D) and O(1S) photoproducts at 11.95-12.22 eV


    Lu, Z; Chang, YC; Benitez, Y; Luo, Z; Houria, AB; Ayari, T; Al Mogren, MM; Hochlaf, M; Jackson, WM; Ng, CY


    © the Owner Societies 2015. The state-to-state photodissociation of CO 2 is investigated in the VUV range of 11.94-12.20 eV by using two independently tunable vacuum ultraviolet (VUV) lasers and the time-sliced velocity-map-imaging-photoion (VMI-PI) method. The spin-allowed CO(X 1 Σ + ; v = 0-18) + O( 1 D) and CO(X 1 Σ + ; v = 0-9) + O( 1 S) photoproduct channels are directl...


    NARCIS (Netherlands)

    Ubachs, W.M.G.; Eikema, K.S.E.; Hogervorst, W.


    Tunable, narrowband extreme ultraviolet radiation in the range 90.5-95 nm with only limited intensity variations is produced by frequency-tripling ultraviolet light from a frequency-doubled dye laser in a gas-jet of xenon. Acetylene gas is found to be an efficient medium for third-harmonic

  8. Fourier Transform Ultraviolet Spectroscopy of the A Pi-2(3/2) Direct Current X Pi-2(3/2) Transition of BrO (United States)

    Wilmouth, David M.; Hanisco, Thomas F.; Donahue, Neil M.; Anderson, James G.


    The first spectra of the A (2)Pi(sub 3/2) from X (2)Pi(sub 3/2) electronic transition of BrO using Fourier transform ultraviolet spectroscopy are obtained. Broadband vibrational spectra acquired at 298 +/- 2 K and 228 +/- 5 K, as well as high-resolution rotational spectra of the A from X 7,0 and 12,0 vibrational bands are presented. Wavenumber positions for the spectra are obtained with high accuracy, and cross section assignments are made, incorporating the existing literature. With 35 cm(exp -1) (0.40 nm) resolution the absolute cross section at the peak of the 7,0 band is determined to be (1.58 +/- 0.12) x 10(exp -17) sq cm/molecule at 298 +/- 2 K and (1.97 +/- 0.15) x 10(exp -17) sq cm/molecule at 228 +/- 5 K. BrO dissociation energies are determined with a graphical Birge-Sponer technique, using Le Roy-Bernstein theory to place an upper limit on the extrapolation. From the ground-state dissociation energy, D(sub o)" = 231.0 +/- 1.7 kJ/mol, the heat of formation of BrO(g) is calculated, del(sub f)H(0 K) = 133.7 +/- 1.7 kJ/mol and del(sub f)H(298.15 K) = 126.2 +/- 1.7 kJ/mol. Cross sections for the high-resolution 7,0 and 12,0 rotational peaks are the first to be reported. The band structures are modeled, and improved band origins, rotational constants, centrifugal distortion constants, and linewidths are determined. In particular, J-dependent linewidths and lifetimes are observed for the both the 7,0 and 12,0 bands.

  9. Linkage of oxygen deficiency defects and rare earth concentrations in silica glass optical fiber probed by ultraviolet absorption and laser excitation spectroscopy. (United States)

    Liu, Y-S; Galvin, T C; Hawkins, T; Ballato, J; Dong, L; Foy, P R; Dragic, P D; Eden, J G


    Ultraviolet absorption measurements and laser excitation spectroscopy in the vicinity of 248 nm provide compelling evidence for linkages between the oxygen deficiency center (ODC) and rare earth concentrations in Yb and Er-doped glass optical fibers. Investigations of YAG-derived and solution-doped glass fibers are described. For both Yb and Er-doped fibers, the dependence of Type II ODC absorption on the rare earth number density is approximately linear, but the magnitude of the effect is greater for Yb-doped fibers. Furthermore, laser excitation spectra demonstrate unambiguously the existence of an energy transfer mechanism coupling an ODC with Yb(3+). Photopumping glass fibers with a Ti:sapphire laser/optical parametric amplifier system, tunable over the 225-265 nm region, or with a KrF laser at 248.4 nm show: 1) emission features in the 200-1100 nm interval attributable only to the ODC (Type II) defect or Yb(3+), and 2) the excitation spectra for ODC (II) emission at ~280 nm and Yb(3+) fluorescence (λ ~1.03 μm) to be, within experimental uncertainty, identical. The latter demonstrates that, when irradiating Yb-doped silica fibers between ~240 and 255 nm, the ODC (II) defect is at least the primary precursor to Yb(3+) emission. Consistent with previous reports in the literature, the data show the ODC (II) absorption spectrum to have a peak wavelength and breadth of ~246 nm and ~19 nm (FWHM). Experiments also reveal that, in the absence of Yb, incorporating either Al(2)O(3) or Y(2)O(3) into glass fibers has a negligible impact on the ODC concentration. Not only do the data reported here demonstrate the relationship between the ODC (II) number density and the Yb doping concentration, but they also suggest that the appearance of ODC defects in the fiber is associated with the introduction of Yb and the process by which the fiber is formed.

  10. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  11. Invariant vacuum (United States)

    Robles-Pérez, Salvador


    We apply the Lewis-Riesenfeld invariant method for the harmonic oscillator with time dependent mass and frequency to the modes of a charged scalar field that propagates in a curved, homogeneous and isotropic spacetime. We recover the Bunch-Davies vacuum in the case of a flat DeSitter spacetime, the equivalent one in the case of a closed DeSitter spacetime and the invariant vacuum in a curved spacetime that evolves adiabatically. In the three cases, it is computed the thermodynamical magnitudes of entanglement between the modes of the particles and antiparticles of the invariant vacuum, and the modification of the Friedmann equation caused by the existence of the energy density of entanglement. The amplitude of the vacuum fluctuations are also computed.

  12. Cosmic vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Chernin, Artur D [P.K. Shternberg State Astronomical Institute at the M.V. Lomonosov Moscow State University, Moscow (Russian Federation)


    Recent observational studies of distant supernovae have suggested the existence of cosmic vacuum whose energy density exceeds the total density of all the other energy components in the Universe. The vacuum produces the field of antigravity that causes the cosmological expansion to accelerate. It is this accelerated expansion that has been discovered in the observations. The discovery of cosmic vacuum radically changes our current understanding of the present state of the Universe. It also poses new challenges to both cosmology and fundamental physics. Why is the density of vacuum what it is? Why do the densities of the cosmic energy components differ in exact value but agree in order of magnitude? On the other hand, the discovery made at large cosmological distances of hundreds and thousands Mpc provides new insights into the dynamics of the nearby Universe, the motions of galaxies in the local volume of 10 - 20 Mpc where the cosmological expansion was originally discovered. (reviews of topical problems)

  13. Vacuum II

    CERN Document Server

    Franchetti, G


    This paper continues the presentation of pumps begun in ‘Vacuum I’. The main topic here is gauges and partial-pressure measurements. Starting from the kinetics of gases, the various strategies for measuring vacuum pressures are presented at an introductory level, with some reference to hardware devices. Partial-pressure measurement techniques are introduced, showing that the principles of ion selection have a direct similarity to particle dynamics in accelerators.

  14. Electronic spectroscopies

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.


    Diffuse reflectance spectroscopy (DRS) in the ultraviolet, visible and near-infrared region is a versatile spectroscopic technique, as both d-d and charge transfer transitions of supported TMI can be probed. One of the advantages of electronic spectroscopy is that the obtained information is

  15. Mass dependence of vacuum energy


    Fulling, S. A.


    The regularized vacuum energy (or energy density) of a quantum field subjected to static external conditions is shown to satisfy a certain partial differential equation with respect to two variables, the mass and the "time" (ultraviolet cutoff parameter). The equation is solved to provide integral expressions for the regularized energy (more precisely, the cylinder kernel) at positive mass in terms of that for zero mass. Alternatively, for fixed positive mass all coefficients in the short-tim...

  16. Rovibrationally selected ion-molecule collision study using the molecular beam vacuum ultraviolet laser pulsed field ionization-photoion method: charge transfer reaction of N2(+)(X 2Σg+; v+ = 0-2; N+ = 0-9) + Ar. (United States)

    Chang, Yih Chung; Xu, Yuntao; Lu, Zhou; Xu, Hong; Ng, C Y


    We have developed an ion-molecule reaction apparatus for state-selected absolute total cross section measurements by implementing a high-resolution molecular beam vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) ion source to a double-quadrupole double-octopole ion-guide mass spectrometer. Using the total cross section measurement of the state-selected N(2)(+)(v(+), N(+)) + Ar charge transfer (CT) reaction as an example, we describe in detail the design of the VUV laser PFI-PI ion source used, which has made possible the preparation of reactant N(2)(+)(X (2)Σ(g)(+), v(+) = 0-2, N(+) = 0-9) PFI-PIs with high quantum state purity, high intensity, and high kinetic energy resolution. The PFI-PIs and prompt ions produced in the ion source are shown to have different kinetic energies, allowing the clean rejection of prompt ions from the PFI-PI beam by applying a retarding potential barrier upstream of the PFI-PI source. By optimizing the width and amplitude of the pulsed electric fields employed to the VUV-PFI-PI source, we show that the reactant N(2)(+) PFI-PI beam can be formed with a laboratory kinetic energy resolution of ΔE(lab) = ± 50 meV. As a result, the total cross section measurement can be conducted at center-of-mass kinetic energies (E(cm)'s) down to thermal energies. Absolute total rovibrationally selected cross sections σ(v(+) = 0-2, N(+) = 0-9) for the N(2)(+)(X (2)Σ(g)(+); v(+) = 0-2, N(+) = 0-9) + Ar CT reaction have been measured in the E(cm) range of 0.04-10.0 eV, revealing strong vibrational enhancements and E(cm)-dependencies of σ(v(+) = 0-2, N(+) = 0-9). The thermochemical threshold at E(cm) = 0.179 eV for the formation of Ar(+) from N(2)(+)(X; v(+) = 0, N(+)) + Ar was observed by the measured σ(v(+) = 0), confirming the narrow ΔE(cm) spread achieved in the present study. The σ(v(+) = 0-2; N(+)) values obtained here are compared with previous experimental and theoretical results. The theoretical predictions

  17. Discrimination of various paper types using diffuse reflectance ultraviolet-visible near-infrared (UV-Vis-NIR) spectroscopy: forensic application to questioned documents. (United States)

    Kumar, Raj; Kumar, Vinay; Sharma, Vishal


    Diffuse reflectance ultraviolet-visible-near-infrared (UV-Vis-NIR) spectroscopy is applied as a means of differentiating various types of writing, office, and photocopy papers (collected from stationery shops in India) on the basis of reflectance and absorbance spectra that otherwise seem to be almost alike in different illumination conditions. In order to minimize bias, spectra from both sides of paper were obtained. In addition, three spectra from three different locations (from one side) were recorded covering the upper, middle, and bottom portions of the paper sample, and the mean average reflectivity of both the sides was calculated. A significant difference was observed in mean average reflectivity of Side A and Side B of the paper using Student's pair >t-test. Three different approaches were used for discrimination: (1) qualitative features of the whole set of samples, (2) principal component analysis, and (3) a combination of both approaches. On the basis of the first approach, i.e., qualitative features, 96.49% discriminating power (DP) was observed, which shows highly significant results with the UV-Vis-NIR technique. In the second approach the discriminating power is further enhanced by incorporating the principal component analysis (PCA) statistical method, where this method describes each UV-Vis spectrum in a group through numerical loading values connected to the first few principal components. All components described 100% variance of the samples, but only the first three PCs are good enough to explain the variance (PC1 = 51.64%, PC2 = 47.52%, and PC3 = 0.54%) of the samples; i.e., the first three PCs described 99.70% of the data, whereas in the third approach, the four samples, C, G, K, and N, out of a total 19 samples, which were not differentiated using qualitative features (approach no. 1), were therefore subjected to PCA. The first two PCs described 99.37% of the spectral features. The discrimination was achieved by using a loading plot between

  18. Comparing 193 nm photoresist roughening in an inductively coupled plasma system and vacuum beam system (United States)

    Titus, M. J.; Nest, D. G.; Chung, T.-Y.; Graves, D. B.


    We present a comparison of blanket 193 nm photoresist (PR) roughening and chemical modifications of samples processed in a well-characterized argon (Ar) inductively coupled plasma (ICP) system and an ultra-high vacuum beam system. In the ICP system, PR samples are irradiated with Ar vacuum ultraviolet (VUV) and Ar ions, while in the vacuum beam system, samples are irradiated with either a Xe-line VUV source or Ar-lamp VUV source with Ar ions. Sample temperature, photon flux, ion flux and ion energy are controlled and measured. The resulting chemical modifications to bulk 193 nm PR and surface roughness are analysed with Fourier transform infrared (FTIR) spectroscopy and atomic force microscopy. We demonstrate that under VUV-only conditions in the vacuum beam and ICP (with no substrate bias applied) systems 193 nm PR does not roughen. However, roughness increases with simultaneous high energy (>70 eV) ion bombardment and VUV irradiation and is a function of VUV fluence, substrate temperature and photon-to-ion flux ratio. PR processed in the ICP system experiences increased etching, probably due to release of H- and O-containing gaseous products and subsequent chemical etching, in contrast to samples in the vacuum beam system where etch-products are rapidly pumped away. The surface roughness structure and behaviour, however, remain similar and this is attributed to the synergy between VUV-photon and positive ions.

  19. Vacuum Valve

    CERN Multimedia


    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  20. CdS and Cd-Free Buffer Layers on Solution Phase Grown Cu2ZnSn(SxSe1- x)4 :Band Alignments and Electronic Structure Determined with Femtosecond Ultraviolet Photoemission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Richard; Barkhouse, Aaron; Wang, Wei; Yu, Luo; Shao, Xiaoyan; Mitzi, David; Hiroi, Homare; Sugimoto, Hiroki


    The heterojunctions formed between solution phase grown Cu2ZnSn(SxSe1- x)4(CZTS,Se) and a number of important buffer materials including CdS, ZnS, ZnO, and In2S3, were studied using femtosecond ultraviolet photoemission spectroscopy (fs-UPS) and photovoltage spectroscopy. With this approach we extract the magnitude and direction of the CZTS,Se band bending, locate the Fermi level within the band gaps of absorber and buffer and measure the absorber/buffer band offsets under flatband conditions. We will also discuss two-color pump/probe experiments in which the band bending in the buffer layer can be independently determined. Finally, studies of the bare CZTS,Se surface will be discussed including our observation of mid-gap Fermi level pinning and its relation to Voc limitations and bulk defects.

  1. High-resolution extreme ultraviolet laser spectroscopy of H2 and D2 in the range from 91 to 98 nm

    NARCIS (Netherlands)

    Hinnen, P. C.; Hogervorst, W.; Stolte, S.; Ubachs, W.


    The present study shows that a coherent laser-based source in the region of the extreme ultraviolet offers great spectroscopic potential and is now applied in various spectroscopic investigations with a resolution and accuracy superior to the best classical spectrographs.

  2. Distillation Kinetics of Solid Mixtures of Hydrogen Peroxide and Water and the Isolation of Pure Hydrogen Peroxide in Ultrahigh Vacuum (United States)

    Teolis, B. D.; Baragiola, R. A.


    We present results of the growth of thin films of crystalline H2O2 and H2O2.2H2O (dihydrate) in ultrahigh vacuum by distilling an aqueous solution of hydrogen peroxide. We traced the process using infrared reflectance spectroscopy, mass loss on a quartz crystal microbalance, and in a few cases ultraviolet-visible reflectance. We find that the different crystalline phases-water, dihydrate, and hydrogen peroxide-have very different sublimation rates, making distillation efficient to isolate the less volatile component, crystalline H2O2.

  3. High precision spectroscopy of 32S, 33S and 34S sulfur dioxide:  Ultraviolet absorption cross sections and fractionation constants

    DEFF Research Database (Denmark)

    Danielache, Sebastian Oscar; Eskebjerg, Carsten; Johnson, Matthew Stanley


    [1] We report measurements of the ultraviolet absorption cross sections of 32SO2, 33SO2, and 34SO2, recorded from 30,300 to 52,500 cm1 (330 to 190 nm) at 293 K with a resolution of 25 cm1. The 33SO2 sample was produced by the combustion of isotopically enriched 33S while the 34SO2 and natural abu...

  4. Wavelength modulation spectroscopy of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kohn, S.E.


    The use of modulation spectroscopy to study the electronic properties of solids has been very productive. The construction of a wide range Wavelength Modulation Spectrometer to study the optical properties of solids is described in detail. Extensions of the working range of the spectrometer into the vacuum ultraviolet are discussed. Measurements of the reflectivity and derivative reflectivity spectra of the lead chalcogenides, the chalcopyrite ZnGeP/sub 2/, the layer compounds GaSe and GaS and their alloys, the ferroelectric SbSI, layer compounds SnS/sub 2/ and SnSe/sub 2/, and HfS/sub 2/ were made. The results of these measurements are presented along with their interpretation in terms of band structure calculations.

  5. Vacuum phenomenon. (United States)

    Yanagawa, Youichi; Ohsaka, Hiromichi; Jitsuiki, Kei; Yoshizawa, Toshihiko; Takeuchi, Ikuto; Omori, Kazuhiko; Oode, Yasumasa; Ishikawa, Kouhei


    This article describes the theory of the formation of the vacuum phenomenon (VP), the detection of the VP, the different medical causes, the different locations of the presentation of the VP, and the differential diagnoses. In the human body, the cavitation effect is recognized on radiological studies; it is called the VP. The mechanism responsible for the formation of the VP is as follows: if an enclosed tissue space is allowed to expand as a rebound phenomenon after an external impact, the volume within the enclosed space will increase. In the setting of expanding volume, the pressure within the space will decrease. The solubility of the gas in the enclosed space will decrease as the pressure of the space decreases. Decreased solubility allows a gas to leave a solution. Clinically, the pathologies associated with the VP have been reported to mainly include the normal joint motion, degeneration of the intervertebral discs or joints, and trauma. The frequent use of CT for trauma patients and the high spatial resolution of CT images might produce the greatest number of chances to detect the VP in trauma patients. The VP is observed at locations that experience a traumatic impact; thus, an analysis of the VP may be useful for elucidating the mechanism of an injury. When the VP is located in the abdomen, it is important to include perforation of the digestive tract in the differential diagnosis. The presence of the VP in trauma patients does not itself influence the final outcome.

  6. Aluminum nanostructures for ultraviolet plasmonics (United States)

    Martin, Jérôme; Khlopin, Dmitry; Zhang, Feifei; Schuermans, Silvère; Proust, Julien; Maurer, Thomas; Gérard, Davy; Plain, Jérôme


    An electromagnetic field is able to produce a collective oscillation of free electrons at a metal surface. This allows light to be concentrated in volumes smaller than its wavelength. The resulting waves, called surface plasmons can be applied in various technological applications such as ultra-sensitive sensing, Surface Enhanced Raman Spectroscopy, or metal-enhanced fluorescence, to name a few. For several decades plasmonics has been almost exclusively studied in the visible region by using nanoparticles made of gold or silver as these noble metals support plasmonic resonances in the visible and near-infrared range. Nevertheless, emerging applications will require the extension of nano-plasmonics toward higher energies, in the ultraviolet range. Aluminum is one of the most appealing metal for pushing plasmonics up to ultraviolet energies. The subsequent applications in the field of nano-optics are various. This metal is therefore a highly promising material for commercial applications in the field of ultraviolet nano-optics. As a consequence, aluminum (or ultraviolet, UV) plasmonics has emerged quite recently. Aluminium plasmonics has been demonstrated efficient for numerous potential applications including non-linear optics, enhanced fluorescence, UV-Surface Enhanced Raman Spectroscopy, optoelectronics, plasmonic assisted solid-state lasing, photocatalysis, structural colors and data storage. In this article, different preparation methods developed in the laboratory to obtain aluminum nanostructures with different geometries are presented. Their optical and morphological characterizations of the nanostructures are given and some proof of principle applications such as fluorescence enhancement are discussed.

  7. Resonance absorption measurements of atom concentrations in reacting gas mixtures. VI. Shapes of the vacuum ultraviolet oxygen (3S-3P) resonance triplet from microwave sources and empirical calibration in a shock tube (United States)

    Pamidimukkala, Krishna M.; Lifshitz, Assa; Skinner, Gordon B.; Wood, David R.


    Spectral line profiles of the atomic oxygen triplet 3S1-3P2,1,0 emitted from microwave discharges in O2-He mixtures containing 0.1% O2 were measured in the 43rd order using a 2 m vacuum Czerny-Turner scanning spectrometer under three different lamp conditions. The profiles varied from nearly Gaussian to highly self-absorbed. The line shapes were accounted for by the amount of light absorbed by ground state oxygen atoms within the lamp. Experiments were carried out to calibrate the microwave discharge lamp for analysis of oxygen atoms using oxygen resonance triplet absorption. Known concentration of O atoms were produced in the temperature range 1950-2600 K in a shock tube by the complete dissociation of dilute (1-20 ppm) mixtures of N2O in Ar and related to the fraction of light absorbed. It was found that the ratios of the intensities of the oxygen components, measured using a low-resolution monochromator, can be used to obtain resonably accurate calibration curves. Kinetic data obtained on N2O dissociation as a part of our calibration experiments in the temperature range 1519-2408 K are also presented; the results are consistent with the correlations of Baulch et al. It was confirmed that O atom concentrations during calibration experiments were determined by stoichiometry, and not by the kinetics of N2O dissociation.

  8. High-resolution extreme ultraviolet spectroscopy of G191-B2B: structure of the stellar photosphere and the surrounding interstellar medium (United States)

    Barstow, M. A.; Cruddace, R. G.; Kowalski, M. P.; Bannister, N. P.; Yentis, D.; Lapington, J. S.; Tandy, J. A.; Hubeny, I.; Schuh, S.; Dreizler, S.; Barbee, T. W.


    We have continued our detailed analysis of the high-resolution (R= 4000) spectroscopic observation of the DA white dwarf G191-B2B, obtained by the Joint Astrophysical Plasmadynamic Experiment (J-PEX) normal incidence sounding rocket-borne telescope, comparing the observed data with theoretical predictions for both homogeneous and stratified atmosphere structures. We find that the former models give the best agreement over the narrow waveband covered by J-PEX, in conflict with what is expected from previous studies of the lower resolution but broader wavelength coverage Extreme Ultraviolet Explorer spectra. We discuss the possible limitations of the atomic data and our understanding of the stellar atmospheres that might give rise to this inconsistency. In our earlier study, we obtained an unusually high ionization fraction for the ionized HeII present along the line of sight to the star. In the present paper, we obtain a better fit when we assume, as suggested by Space Telescope Imaging Spectrograph results, that this HeII resides in two separate components. When one of these is assigned to the local interstellar cloud, the implied He ionization fraction is consistent with measurements along other lines of sight. However, the resolving power and signal-to-noise available from the instrument configuration used in this first successful J-PEX flight are not sufficient to clearly identify and prove the existence of the two components.

  9. Preparation of SnS thin films with gear-like sheet appearance by close-spaced vacuum thermal evaporation (United States)

    Shao, Zhangpeng; Shi, Chengwu; Chen, Junjun; Zhang, Yanru


    SnS thin films with gear-like sheet appearance were successfully prepared by close-spaced vacuum thermal evaporation using SnS powders as a source. The influence of substrate temperature on the surface morphology, chemical composition, crystal structure and optical property of SnS thin films was investigated by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and ultraviolet-visible-near infrared spectroscopy. The results revealed that serration architecture appeared obviously in the edge of the SnS sheet and the strongest peak at 2𝜃=31.63∘ was broadened and many shoulder peaks were observed with increasing substrate temperature. The atomic ratio of Sn to S increased from 1:1.08 to 1:1.20, the grain size became slightly smaller and the optical absorption edge had a blueshift in the SnS thin film with decreasing substrate temperature.

  10. On the use of the fluorescence, ultraviolet-visible and near infrared spectroscopy with chemometrics for the discrimination between plum brandies of different varietal origins. (United States)

    Jakubíková, M; Sádecká, J; Kleinová, A


    This paper investigates the use of synchronous fluorescence, UV-Vis and near infrared (NIR) spectroscopy coupled with chemometric methods to discriminate samples of high-quality plum brandies (Slivovica) of different varietal origins (Prunus domestica L.). Synchronous fluorescence spectra (SFS) for wavelength differences in the range of 70-100nm, NIR spectra in the wavenumber range of 4000-7500cm(-1) and UV-Vis spectra in the wavelength interval of 220-320nm were compared. The best discrimination models were created by linear discriminant analysis based on principal component analysis applied to SFS recorded with wavelength difference either 80nm or 100nm, allowing the classification of plum brandy according to harvest time as early (summer) and late (autumn) plum varieties; the total correct classifications were 96% and 100% for the calibration and prediction steps, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Photo-physics study of an hydroxy-quinoline derivative as inhibitor of Pim-1 kinase: ultraviolet-visible linear dichroism spectroscopy and quantum chemical calculations. (United States)

    Lamhasni, T; Ait Lyazidi, S; Hnach, M; Haddad, M; Desmaële, D; Spanget-Larsen, J; Nguyen, D D; Ducasse, L


    The photophysical properties of the antiviral 7-nicotinoyl-styrylquinoline (MB96) were investigated by means of UV-Vis linear dichroism (LD) spectroscopy on molecular samples aligned in stretched polyvinylalcohol (PVA), supported by time dependent density functional theory (TD-DFT) calculations. Experimentally, the directions of the transitions moments with respect to the long axis of the molecule were deduced from the orientation K factors, determined by means of "trial-and-error" procedure. The absorption spectrum presents two parts. The main transition in the lowest energy part, observed around 365 nm and showing the highest K value 0.8, is longitudinally in-plane polarized. The highest energy part which is extended between 230 and 320 nm, large, diffuse, and of weak intensity, shows estimated K values between 0.2 and 0.5. This complex structure is transversally polarized with some contamination by the longitudinal character of the first strong band. The TD-DFT results agree fairly well with the LD measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Application of chemometrics in quality control of Turmeric (Curcuma longa) based on Ultra-violet, Fourier transform-infrared and1H NMR spectroscopy. (United States)

    Gad, Haidy A; Bouzabata, Amel


    Turmeric (Curcuma longa L.) belongs to the family Zingiberaceae that is widely used as a spice in food preparations in addition to its biological activities. UV, FT-IR, 1 H NMR in addition to HPLC were applied to construct a metabolic fingerprint for Turmeric in an attempt to assess its quality. 30 samples were analyzed, and then principal component analysis (PCA) and hierarchical clustering analysis (HCA) were utilized to assess the differences and similarities between collected samples. PCA score plot based on both HPLC and UV spectroscopy showed the same discriminatory pattern, where the samples were segregated into four main groups depending on their total curcuminoids content. The results revealed that UV could be utilized as a simple and rapid alternative for HPLC. However, FT-IR failed to discriminate between the same species. By applying 1 H NMR, the metabolic variability between samples was more evident in the essential oils/fatty acid region. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Conformation-Specific Infrared and Ultraviolet Spectroscopy of Cold [YAPAA+H]^{+} and [YGPAA+H]^{+} Ions: a Stereochemical "twist" on the β-HAIRPIN Turn (United States)

    DeBlase, Andrew F.; Harrilal, Christopher P.; Lawler, John T.; Burke, Nicole L.; McLuckey, Scott A.; Zwier, Timothy S.


    Incorporation of the unnatural D-proline (^{D}P) stereoisomer into a polypeptide sequence is a typical strategy to encourage formation of β-hairpin loops because natural sequences are often unstructured in solution. Using conformation-specific IR and UV spectroscopy of cold (10 K) gas-phase ions, we probe the inherent conformational preferences of the ^{D}P and ^{L}P diastereomers in the protonated peptide [YAPAA+H]^{+}, where only intramolecular interactions are possible. Consistent with the solution phase studies, one of the conformers of [YADPAA+H]^{+} is folded into a charge-stabilized β-hairpin turn. However, a second predominant conformer family containing two sequential γ-turns is also identified, with similar energetic stability. A single conformational isomer of the ^{L}P diastereomer, [YALPAA+H]^{+}, is found and assigned to a structure that is not the anticipated "mirror image" β-turn. Instead, the ^{L}P stereo center promotes a cis alanine-proline amide bond. The assigned structures contain clues that the preference of the ^{D}P diastereomer to support a trans-amide bond and the proclivity of ^{L}P for a cis-amide bond is sterically driven and can be reversed by substituting glycine for alanine in position 2, forming [YGLPAA+H]^{+}. These results provide a basis for understanding the residue-specific and stereo-specific alterations in the potential energy surface that underlie these changing preferences, providing insights to the origin of β-hairpin formation.

  14. Biomolecular and structural analyses of cauliflower-like DNAs by ultraviolet, circular dichroism, and fluorescence spectroscopies in comparison with natural DNA. (United States)

    Gill, Pooria; Ranjbar, Bijan; Saber, Reza; Khajeh, Khosro; Mohammadian, Mehdi


    Cauliflower-like DNAs are stem-loop DNAs that are fabricated periodically in inverted repetitions from deoxyribonucleic acid phosphates (dNTPs) by loop-mediated isothermal amplification (LAMP). Cauliflower-like DNAs have ladder-shape behaviors on gel electrophoresis, and increasing the time of LAMP leads to multiplying the repetitions, stem-loops, and electrophoretic bands. Cauliflower-like DNAs were fabricated via LAMP using two loop primers, two bumper primers, dNTPs, a λ-phage DNA template, and a Bst DNA polymerase in 75- and 90-min periods. These times led to manufacturing two types of cauliflower-like DNAs with different contents of inverted repetitions and stem-loops, which were clearly indicated by two comparable electrophoresis patterns in agarose gel. LAMP-fabricated DNAs and natural dsB-DNA (salmon genomic DNA) were dialyzed in Gomori phosphate buffer (10 mM, pH 7.4) to be isolated from salts, nucleotides, and primers. Dialyzed DNAs were studied using UV spectroscopy, circular dichroism spectropolarimetry, and fluorescence spectrophotometry. Structural analyses indicated reduction of the molecular ellipticity and extinction coefficients in comparison with B-DNA. Also, cauliflower-like DNAs demonstrated less intrinsic and more extrinsic fluorescence in comparison with natural DNA. The overwinding and lengthening of the cauliflower-like configurations of LAMP DNAs led to changes in physical parameters of this type of DNA in comparison with natural DNA. The results obtained introduced new biomolecular characteristics of DNA macromolecules fabricated within a LAMP process and show the effects of more inverted repeats and stem-loops, which are manufactured by lengthening the process.

  15. Ultraviolet photosulfidation of III-V compound semiconductors for electronic passivation

    Energy Technology Data Exchange (ETDEWEB)

    Zavadil, K.R.; Ashby, C.I.H.; Howard, A.J.; Hammons, B.E.


    A new vacuum-compatible passivation technique for III-V compound semiconductors has been developed. Sulfur passivation of GaAs(100) is produced by ultraviolet photolytic deposition of a sulfide species from vapor phase elemental sulfur. Photoluminescence studies of the photosulfided GaAs reveal a degree of passivation greater than or equal to that produced by conventional (NH{sub 4}{sub 2}S) solution treatment. X-ray Photoelectron Spectroscopy has shown that the sulfur resides on the surface as a single reduced sulfur species, either as sulfide of disulfide, indicating complete fragmentation of the S{sub 8} ring by UV light in proximity to the surface. The degree of photosulfidation depends strongly on surface preparation as demonstrated by the described surface oxide removal studies.

  16. Ultraviolet observations of comet Hale-Bopp (United States)

    Feldman, Paul D.


    Ultraviolet spectroscopy and imaging of comet Hale-Bopp (C/1995 O1) were obtained from a variety of space platforms from shortly after the discovery of the comet through perihelion passage. Observations with the International Ultraviolet Explorer (IUE) and the Hubble Space Telescope (HST) spanned the range of 6.8 to 2.7 AU pre-perihelion, but IUE was decommissioned in September 1996 and HST was precluded from near-perihelion observations because of its solar avoidance constraint. In September 1996, observations were made by the Extreme Ultraviolet Explorer (EUVE) that showed the presence of soft X-rays offset from the optical center of the coma and provided a sensitive spectroscopic upper limit to the Ne/O abundance ratio. During the perihelion period NASA mounted a successful campaign of four sounding rockets that were launched at the White Sands Missile Range, New Mexico, between March 25 and April 8, 1997. The payloads included long-slit spectroscopy and ultraviolet imaging polarimetry. In addition, Hale-Bopp was observed near perihelion by ultraviolet instruments on orbiting spacecraft that were designed for solar or terrestrial observations. Observations with HST, using the Space Telescope Imaging Spectrograph (STIS), installed during the February 1997 servicing mission, resumed in August 1997. Intercomparison of the ultraviolet observations and comparison with the results on gas composition and activity from ground-based visible, infrared and radio observations may permit the resolution of many discrepant results present in the literature.

  17. Quantum yields of decomposition and homo-dimerization of solid L-alanine induced by 7.2 eV Vacuum ultraviolet light irradiation: an estimate of the half-life of L-alanine on the surface of space objects. (United States)

    Izumi, Yudai; Nakagawa, Kazumichi


    One of the leading hypotheses regarding the origin of prebiotic molecules on primitive Earth is that they formed from inorganic molecules in extraterrestrial environments and were delivered by meteorites, space dust and comets. To evaluate the availability of extraterrestrial amino acids, it is necessary to examine their decomposition and oligomerization rates as induced by extraterrestrial energy sources, such as vacuum ultraviolet (VUV) and X-ray photons and high energy particles. This paper reports the quantum yields of decomposition ((8.2 ± 0.7) × 10(-2) photon(-1)) and homo-dimerization ((1.2 ± 0.3) × 10(-3) photon(-1)) and decomposition of the dimer (0.24 ± 0.06 photon(-1)) of solid L-alanine (Ala) induced by VUV light with an energy of 7.2 eV. Using these quantum yields, the half-life of L-Ala on the surface of a space object in the present earth orbit was estimated to be about 52 days, even when only photons with an energy of 7.2 eV emitted from the present Sun were considered. The actual half-life of solid L-Ala on the surface of a space object orbit around the present day Earth would certainly be much shorter than our estimate, because of the added effect of photons and particles of other energies. Thus, we propose that L-Ala needs to be shielded from solar VUV in protected environments, such as the interior of a meteorite, within a time scale of days after synthesis to ensure its arrival on the primitive Earth.

  18. Biological applications of ultraviolet free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, J.C.


    This review examines the possibilities for biological research using the three ultraviolet free-electron lasers that are nearing operational status in the US. The projected operating characteristics of major interest in biological research of the free-electron lasers at Brookhaven National Laboratory, the Thomas Jefferson National Accelerator Facility, and Duke University are presented. Experimental applications in the areas of far- and vacuum ultraviolet photophysics and photochemistry, structural biology, environmental photobiology, and medical research are discussed and the prospects for advances in these areas, based upon the characteristics of the new ultraviolet free-electron lasers, are evaluated.

  19. Nanoscale Vacuum Channel Transistor. (United States)

    Han, Jin-Woo; Moon, Dong-Il; Meyyappan, M


    Vacuum tubes that sparked the electronics era had given way to semiconductor transistors. Despite their faster operation and better immunity to noise and radiation compared to the transistors, the vacuum device technology became extinct due to the high power consumption, integration difficulties, and short lifetime of the vacuum tubes. We combine the best of vacuum tubes and modern silicon nanofabrication technology here. The surround gate nanoscale vacuum channel transistor consists of sharp source and drain electrodes separated by sub-50 nm vacuum channel with a source to gate distance of 10 nm. This transistor performs at a low voltage (3 microamperes). The nanoscale vacuum channel transistor can be a possible alternative to semiconductor transistors beyond Moore's law.

  20. Indian Vacuum Society: The Indian Vacuum Society (United States)

    Saha, T. K.


    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  1. Widely tunable extreme ultraviolet frequency comb generation

    NARCIS (Netherlands)

    Pinkert, T. J.; Kandula, D. Z.; Gohle, Ch; Morgenweg, J.; Barmes, I.; Ubachs, W.; Eikema, K. S E


    Frequency comb lasers [1] have led to great advances in fields such as precision spectroscopy, optical atomic clocks, and attosecond science. We transfer the remarkable precision of frequency combs to extreme ultraviolet (XUV) wavelengths by parametric amplification and high-harmonic generation

  2. Ultraviolet photochemical reaction of [Fe(III(C2O43]3− in aqueous solutions studied by femtosecond time-resolved X-ray absorption spectroscopy using an X-ray free electron laser

    Directory of Open Access Journals (Sweden)

    Y. Ogi


    Full Text Available Time-resolved X-ray absorption spectroscopy was performed for aqueous ammonium iron(III oxalate trihydrate solutions using an X-ray free electron laser and a synchronized ultraviolet laser. The spectral and time resolutions of the experiment were 1.3 eV and 200 fs, respectively. A femtosecond 268 nm pulse was employed to excite [Fe(III(C2O43]3− in solution from the high-spin ground electronic state to ligand-to-metal charge transfer state(s, and the subsequent dynamics were studied by observing the time-evolution of the X-ray absorption spectrum near the Fe K-edge. Upon 268 nm photoexcitation, the Fe K-edge underwent a red-shift by more than 4 eV within 140 fs; however, the magnitude of the redshift subsequently diminished within 3 ps. The Fe K-edge of the photoproduct remained lower in energy than that of [Fe(III(C2O43]3−. The observed red-shift of the Fe K-edge and the spectral feature of the product indicate that Fe(III is upon excitation immediately photoreduced to Fe(II, followed by ligand dissociation from Fe(II. Based on a comparison of the X-ray absorption spectra with density functional theory calculations, we propose that the dissociation proceeds in two steps, forming first [(CO2•Fe(II(C2O42]3− and subsequently [Fe(II(C2O42]2−.

  3. In-orbit Calibrations of the Ultraviolet Imaging Telescope

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, S. N. [Inter-University Center for Astronomy and Astrophysics, Pune (India); Subramaniam, Annapurni; Sankarasubramanian, K.; Sriram, S.; Stalin, C. S.; Mondal, C.; Sahu, S.; Joseph, P.; Barve, I. V.; George, K.; Kamath, P. U.; Kathiravan, S.; Kumar, A.; Lancelot, J. P.; Mahesh, P. K. [Indian Institute of Astrophysics, Koramangala II Block, Bangalore-560034 (India); Girish, V. [ISRO Satellite Centre, HAL Airport Road, Bangalore 560017 (India); Postma, J.; Leahy, D. [University of Calgary, 2500 University Drive NW, Calgary, Alberta Canada (Canada); Hutchings, J. [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Ghosh, S. K., E-mail: [National Centre for Radio Astrophysics, Pune (India); and others


    The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300–1800 Å), and the other for the near-ultraviolet (NUV) channel (2000–3000 Å) and the visible (VIS) channel (3200–5500 Å). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.″8, along with provisions for slit-less spectroscopy in the NUV and FUV channels. The results of in-orbit calibrations of UVIT are presented in this paper.

  4. The vacuum disconnector

    Energy Technology Data Exchange (ETDEWEB)

    Schellekens, H.


    After showing the extended experience of Holec with vacuum disconnectors, the difficulties encountered in developing the type SVS vacuum bottle are indicated. The implications of demands imposed on price and dimensions are translated into design features. The function and the design of the getter is explained to show how Holec guarantees a 20 year approved vacuum in the bottle. Finally, the results of switching tests are mentioned to explain the reliability and capability of the new disconnector. 12 figs.

  5. Effects of Vacuum Ultraviolet Radiation on Thin Polyimide Films Evaluated (United States)

    Dever, Joyce A.; Messer, Russell K.; Powers, Charles; Townsend, Jacqueline A.; Wooldridge, Eve


    NASA anticipates launching the Next Generation Space Telescope (NGST) mission-- whose purpose is to examine the origins of our universe by making measurements in the infrared portion of the spectrum--in 2009. So that the telescope can operate at very low temperatures (less than 100 K), a halo orbit about the second Lagrangian point (L2) is being considered because it is far from Earth and its reflected sunlight. The Sun-Earth L2 point is located 1.53 10(exp 6) km from the Earth in the direction away from the Sun. This mission presents new challenges in many areas of technology, including the development of a multilayer insulation sunshield for the telescope. This sunshield is required to be large (proposed dimensions of approximately 33 by 14 m), storable, deployable, and lightweight. In addition, its polymer film layers must be seamable, foldable, and resistant to tearing and creep, with low outgassing. The sunshield must maintain its structural integrity and its Sun-facing side must maintain a low solar absorptance to thermal emittance ratio (alpha/epsilon) over the planned 10-yr mission duration including over 80,000 hr facing constant sunlight.

  6. Vacuum ultraviolet photoionization and photodissociation of polyatomic molecules and radicals

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.Y. [Iowa State Univ., Ames (United States)


    In the past decade, tremendous progress has been made in understanding the photodissociation (PD) dynamics of triatomic molecules. However, the PD study of radicals, especially polyatomic radicals, has remained essentially an unexplored research area. Detailed state-to-state PD cross sections for radicals in the UV and VUV provide challenges not only for dynamical calculations, but also for ab initio quantum chemical studies. The authors have developed a laser based pump-probe apparatus for the measurement of absolute PD cross sections for CH{sub 3}S and HS is summarized.

  7. Vacuum polarization in Coulomb field revisited

    Energy Technology Data Exchange (ETDEWEB)

    Zamastil, J., E-mail:; Šimsa, D.


    Simplified derivation of Wichmann–Kroll term is presented. The derivation uses two formulas for hypergeometric functions, but otherwise is elementary. It is found that Laplace transform of the vacuum charge density diverges at zero momentum transfer. This divergence has nothing to do with known ultraviolet divergence. The latter is related to the large momentum behavior of the pertinent integral, while the former to the small momentum behavior. When these divergences are removed, the energy shift caused by vacuum polarization for an ordinary hydrogen obtained here is in an exact agreement with the result obtained by Wichmann and Kroll. Also, for muonic hydrogen the result obtained here reasonably agrees with that given in literature.

  8. Implementation of Deep Ultraviolet Raman Spectroscopy

    DEFF Research Database (Denmark)

    Liu, Chuan

    – is a DUV laser in which the line is achieved by a highly complex frequency quadrupling device. Such a laser is obtainable as a product from TOPTICA Photonics. With respect to the solid-state laser possibility, we devoted ourselves to distinguish between wavelength tuneable and un-tuneable lasers...... excitation because of fluorescence interferences. Raman spectra of Sudan I - without fluorescence interferences - could be achieved by use of the 244.0 nm excitation. The DUV Raman spectrometry could thus be a potential detection method for Sudan I, as an illegal food colorant. The fluorescence-free DUV...

  9. Seeing Core-Collapse Supernovae in the Ultraviolet (United States)

    Brown, Peter

    Core-collapse supernovae are the catastrophic deaths of massive stars. Ultraviolet observations are needed to understand the energy of the explosion through the study of the bolometric light curves. Early-time ultraviolet observations constrain the size of the progenitor. Ultraviolet spectra can break the degeneracies between temperature/ionization, reddening, and metallicity which hinder our understanding of ultraviolet photometry. Optical observations of high-redshift supernovae probe rest-frame ultraviolet wavelengths, requiring space-based observations of nearby supernovae against which to compare. Ultraviolet observations of core-collapse supernovae can also help distinguish them from type Ia supernovae, enabling cleaner photometric type Ia supernova samples for cosmological measurements. The Ultraviolet/Optical Telescope (UVOT) on the Swift satellite has observed over two hundred core-collapse supernovae in the ultraviolet, including sixty-nine ultraviolet grism spectra of twenty core-collapse SNe. Additional ultraviolet spectra have been obtained by the International Ultraviolet Explorer, Hubble Space Telescope, and Galaxy Evolution Explorer. We propose a project to reduce the Swift grism spectra and combine with the other ultraviolet and groundbased optical/NIR spectra to create time-series bolometric spectra. We will use these bolometric spectra to better understand temperature, reddening, and metallicity and create bolometric light curves of these core collapse SNe. We will also use early time ultraviolet photometry and spectroscopy to constrain the progenitors of core collapse SNe. The ultraviolet observations fill a critical niche in our understanding of core collapse supernovae, and this program will enhance the scientific use of this important dataset from multiple space missions. Beyond core-collapse supernovae, the templates will allow studies of the dust properties around the progenitor systems (including the wavelength dependence of the extinction

  10. Microfabricated triggered vacuum switch (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM


    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  11. Insulation vacuum and beam vacuum overpressure release

    CERN Document Server

    Parma, V


    There is evidence that the incident of 19th September caused a high pressure build-up inside the cryostat insulation vacuum which the existing overpressure devices could not contain. As a result, high longitudinal forces acting on the insulation vacuum barriers developed and broke the floor and the floor fixations of the SSS with vacuum barriers. The consequent large longitudinal displacements of the SSS damaged chains of adjacent dipole cryo-magnets. Estimates of the helium mass flow and the pressure build- up experienced in the incident are presented together with the pressure build-up for an even more hazardous event, the Maximum Credible Incident (MCI). The strategy of limiting the maximum pressure by the installation of addition pressure relieve devices is presented and discussed. Both beam vacuum lines were ruptured during the incident in sector 3-4 giving rise to both mechanical damage and pollution of the system. The sequence, causes and effects of this damage will be briefly reviewed. We will then an...

  12. A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy. (United States)

    Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis


    Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70-55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 (d10), 3.025 (d50), and 6.712 (d90) μm and average surface area of 2.71 m2/g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed Tmax at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λmax), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn-Cl stretching. These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications.

  13. Photodiode-Based, Passive Ultraviolet Dosimeters (United States)

    Vaughn, Jason A.; Gray, Perry


    Simple, passive instruments have been developed for measuring the exposure of material specimens to vacuum ultraviolet (VUV) radiation from the Sun. Each instrument contains a silicon photodiode and a coulometer. The photocharge generated in the photodiode is stored in the coulometer. The accumulated electric charge measured by use of the coulometer is assumed to be proportional to the cumulative dose of VUV radiation expressed in such convenient units as equivalent Sun hours (ESH) [defined as the number of hours of exposure to sunlight at normal incidence]. Intended originally for use aboard spacecraft, these instruments could also be adapted to such terrestrial uses as monitoring the curing of ultraviolet-curable epoxies. Each instrument includes a photodiode and a coulometer assembly mounted on an interface plate (see figure). The photodiode assembly includes an aluminum housing that holds the photodiode, a poly(tetrafluoroehylene) cosine receptor, and a narrow-band optical filter. The cosine receptor ensures that the angular response of the instrument approximates the ideal angular response (proportional to the cosine of the angle of incidence). The filter is chosen to pass the ultraviolet wavelength of interest in a specific experiment. The photodiode is electrically connected to the coulometer. The factor of proportionality between the charge stored in the coulometer and ultraviolet dosage (in units of ESH) is established, prior to use, in calibration experiments that involve the use of lamps and current sources traceable to the National Institute of Standards and Technology.

  14. Evolution of Structural and Optical Properties of ZnO Nanorods Grown on Vacuum Annealed Seed Crystallites. (United States)

    Khan, Waqar; Khan, Fasihullah; Ajmal, Hafiz Muhammad Salman; Huda, Noor Ul; Kim, Ji Hyun; Kim, Sam-Dong


    In this study, the ambient condition for the as-coated seed layer (SL) annealing at 350 °C is varied from air or nitrogen to vacuum to examine the evolution of structural and optical properties of ZnO nanorods (NRs). The NR crystals of high surface density (~240 rods/μm²) and aspect ratio (~20.3) show greatly enhanced (002) degree of orientation and crystalline quality, when grown on the SLs annealed in vacuum, compared to those annealed in air or nitrogen ambient. This is due to the vacuum-annealed SL crystals of a highly preferred orientation toward (002) and large grain sizes. X-ray photoelectron spectroscopy also reveals that the highest O/Zn atomic ratio of 0.89 is obtained in the case of vacuum-annealed SL crystals, which is due to the effective desorption of hydroxyl groups and other contaminants adsorbed on the surface formed during aqueous solution-based growth process. Near band edge emission (ultra violet range of 360-400 nm) of the vacuum-annealed SLs is also enhanced by 44% and 33% as compared to those annealed in air and nitrogen ambient, respectively, in photoluminescence with significant suppression of visible light emission associated with deep level transition. Due to this improvement of SL optical crystalline quality, the NR crystals grown on the vacuum-annealed SLs produce ~3 times higher ultra violet emission intensity than the other samples. In summary, it is shown that the ZnO NRs preferentially grow along the wurtzite c-axis direction, thereby producing the high crystalline quality of nanostructures when they grow on the vacuum-annealed SLs of high crystalline quality with minimized impurities and excellent preferred orientation. The ZnO nanostructures of high crystalline quality achieved in this study can be utilized for a wide range of potential device applications such as laser diodes, light-emitting diodes, piezoelectric transducers and generators, gas sensors, and ultraviolet detectors.

  15. Vacuum spin squeezing (United States)

    Hu, Jiazhong; Chen, Wenlan; Vendeiro, Zachary; Urvoy, Alban; Braverman, Boris; Vuletić, Vladan


    We investigate the generation of entanglement (spin squeezing) in an optical-transition atomic clock through the coupling to an optical cavity in its vacuum state. We show that if each atom is prepared in a superposition of the ground state and a long-lived electronic excited state, and viewed as a spin-1/2 system, then the collective vacuum light shift entangles the atoms, resulting in a squeezed distribution of the ensemble collective spin, without any light applied. This scheme reveals that even an electromagnetic vacuum can constitute a useful resource for entanglement and quantum manipulation. By rotating the spin direction while coupling to the vacuum, the scheme can be extended to implement two-axis twisting resulting in stronger squeezing.

  16. Handbook of vacuum technology

    CERN Document Server


    This comprehensive, standard work has been updated to remain an important resource for all those needing detailed knowledge of the theory and applications of vacuum technology. With many numerical examples and illustrations to visualize the theoretical issues.

  17. Cold Vacuum Drying Facility (United States)

    Federal Laboratory Consortium — Located near the K-Basins (see K-Basins link) in Hanford's 100 Area is a facility called the Cold Vacuum Drying Facility (CVDF).Between 2000 and 2004, workers at the...

  18. Vacuum-assisted delivery (United States)

    ... the birth canal. The vacuum uses a soft plastic cup that attaches to the baby's head with suction. ... a numbing medicine placed in the vagina. The plastic cup will be placed on the baby's head. Then, ...

  19. Ultra high vacuum technology

    CERN Multimedia

    CERN. Geneva


    A short introduction for some basic facts and equations. Subsquently, discussion about: Building blocks of an ultrahigh vacuum system - Various types of pumps required to reach uhv and methods to reduce these effects - Outgassing phenomena induced by the presence of a particle beam and the most common methods to reduce these effects It will be given some practical examples from existing CERN accelerators and discuss the novel features of the future LHC vacuum system.

  20. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry


    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  1. A Planck Vacuum Cosmology

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.


    Full Text Available Both the big-bang and the quasi-steady-state cosmologies originate in some type of Planck state. This paper presents a new cosmological theory based on the Planck- vacuum negative-energy state, a state consisting of a degenerate collection of negative- energy Planck particles. A heuristic look at the Einstein field equation provides a con- vincing argument that such a vacuum state could provide a theoretical explanation for the visible universe.

  2. State-to-state vacuum ultraviolet photodissociation study of CO2 on the formation of state-correlated CO(X(1)Σ(+); v) with O((1)D) and O((1)S) photoproducts at 11.95-12.22 eV. (United States)

    Lu, Zhou; Chang, Yih Chung; Benitez, Yanice; Luo, Zhihong; Houria, Adel Ben; Ayari, Tarek; Al Mogren, Muneerah Mogren; Hochlaf, M; Jackson, W M; Ng, C Y


    The state-to-state photodissociation of CO2 is investigated in the VUV range of 11.94-12.20 eV by using two independently tunable vacuum ultraviolet (VUV) lasers and the time-sliced velocity-map-imaging-photoion (VMI-PI) method. The spin-allowed CO(X(1)Σ(+); v = 0-18) + O((1)D) and CO(X(1)Σ(+); v = 0-9) + O((1)S) photoproduct channels are directly observed from the measurement of time-sliced VMI-PI images of O((1)D) and O((1)S). The total kinetic energy release (TKER) spectra obtained based on these VMI-PI images shows that the observed energetic thresholds for both the O((1)D) and O((1)S) channels are consistent with the thermochemical thresholds. Furthermore, the nascent vibrational distributions of CO(X(1)Σ(+); v) photoproducts formed in correlation with O((1)D) differ significantly from that produced in correlation with O((1)S), indicating that the dissociation pathways for the O((1)D) and O((1)S) channels are distinctly different. For the O((1)S) channel, CO(X(1)Σ(+); v) photoproducts are formed mostly in low vibrational states (v = 0-2), whereas for the O((1)D) channel, CO(X(1)Σ(+); v) photoproducts are found to have significant populations in high vibrationally excited states (v = 10-16). The anisotropy β parameters for the O((1)D) + CO(X(1)Σ(+); v = 0-18) and O((1)S) + CO(X(1)Σ(+); v = 0-9) channels have also been determined from the VMI-PI measurements, indicating that CO2 dissociation to form the O((1)D) and O((1)S) channels is faster than the rotational periods of the VUV excited CO2 molecules. We have also calculated the excited singlet potential energy surfaces (PESs) of CO2, which are directly accessible by VUV excitation, at the ab initio quantum multi-reference configuration interaction level of theory. These calculated PESs suggest that the formation of CO(X(1)Σ(+)) + O((1)S) photoproducts occurs nearly exclusively on the 4(1)A' PES, which is generally repulsive with minor potential energy ripples along the OC-O stretching coordinate. The

  3. Effect of the ultraviolet light treatment and storage methods on the biological activity of a titanium implant surface. (United States)

    Choi, Sung-Hwan; Jeong, Won-Seok; Cha, Jung-Yul; Lee, Jae-Hoon; Lee, Kee-Joon; Yu, Hyung-Seog; Choi, Eun-Ha; Kim, Kwang-Mahn; Hwang, Chung-Ju


    We evaluated whether the biological activity of the surface of titanium, when stored in an aqueous solution, in low vacuum, and under ambient conditions after ultraviolet light (UV) treatment is comparable to that of the surface immediately after UV treatment for 15min and that after dielectric barrier discharge (DBD) plasma treatment for 15min. Grade IV titanium discs with machined surfaces were irradiated with UV and their surface properties were evaluated immediately and after storage for 28days in distilled H2O (dH2O), a vacuum desiccator (31.325kPa), and a sealed container under air. Their surface characteristics were evaluated by atomic force microscopy, X-ray diffraction, contact angle analysis, and X-ray photoelectron spectroscopy. Biological activities were determined by analyzing the albumin adsorption, MC3T3-E1 cell adhesion, and cytoskeleton development. Hydrophilicity of titanium surfaces stored in dH2O was comparable to that immediately after UV treatment and higher than that immediately after DBD plasma treatment (PStorage in dH2O and in low vacuum immediately after UV treatment prevented hydrocarbon contamination and maintained elevated amounts of titanium and oxygen. After 28 days, protein adsorption, cellular adhesion, and cytoskeletal development of MC3T3-E1 cells on the titanium surfaces stored in dH2O were significantly enhanced compared to those stored in low vacuum and under ambient conditions while being comparable to those immediately after UV and DBD plasma treatments. UV treatment of the titanium implants followed by wet storage is useful for maintaining enhanced biological activity and overcoming biological aging during shelf storage. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. Optical properties and electronic transitions of zinc oxide, ferric oxide, cerium oxide, and samarium oxide in the ultraviolet and extreme ultraviolet

    DEFF Research Database (Denmark)

    Pauly, N; Yubero, F; Espinós, J P


    Optical properties and electronic transitions of four oxides, namely zinc oxide, ferric oxide, cerium oxide, and samarium oxide, are determined in the ultraviolet and extreme ultraviolet by reflection electron energy loss spectroscopy using primary electron energies in the range 0.3-2.0 keV. This...

  5. Exploring the structure of the quenched QCD vacuum with overlap fermions

    Energy Technology Data Exchange (ETDEWEB)

    Ilgenfritz, E.M. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Koller, K. [Muenchen Univ. (Germany). Sektion Physik; Koma, Y. [Mainz Univ. (Germany). Inst. fuer Kernphysik; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Streuer, T. [Kentucky Univ., Lexington, KY (United States). Dept. of Physics and Astronomy; Weinberg, V. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)]|[Freie Univ. Berlin (Germany). Inst. fuer Theoretische Physik


    Overlap fermions have an exact chiral symmetry on the lattice and are thus an appropriate tool for investigating the chiral and topological structure of the QCD vacuum. We study various chiral and topological aspects of quenched gauge field configurations. This includes the localization and chiral properties of the eigenmodes, the local structure of the ultraviolet filtered field strength tensor, as well as the structure of topological charge fluctuations. We conclude that the vacuum has a multifractal structure. (orig.)

  6. Improving Vacuum Cleaners (United States)


    Under a Space Act Agreement between the Kirby company and Lewis Research Center, NASA technology was applied to a commercial vacuum cleaner product line. Kirby engineers were interested in advanced operational concepts, such as particle flow behavior and vibration, critical factors to improve vacuum cleaner performance. An evaluation of the company 1994 home care system, the Kirby G4, led to the refinement of the new G5 and future models. Under the cooperative agreement, Kirby had access to Lewis' holography equipment, which added insight into how long a vacuum cleaner fan would perform, as well as advanced computer software that can simulate the flow of air through fans. The collaboration resulted in several successes including fan blade redesign and continuing dialogue on how to improve air-flow traits in various nozzle designs.

  7. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.


    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  8. Baryogenesis in false vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Yuta [KEK Theory Center, IPNS, KEK, Tsukuba, Ibaraki (Japan); Yamada, Masatoshi [Kanazawa University, Institute for Theoretical Physics, Kanazawa (Japan)


    The null result in the LHC may indicate that the standard model is not drastically modified up to very high scales, such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops a large vacuum expectation value in the early universe, a lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with higher-dimensional operators. (orig.)

  9. A rotating quantum vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lorenci, V.A. de; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)


    It was investigated which mapping has to be used to compare measurements made in a rotating frame to those made in an inertial frame. Using a non-Galilean coordinate transformation, the creation-annihilation operators of a massive scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state(a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. Polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view were analysed. 65 refs.

  10. Handbook of vacuum physics

    CERN Document Server


    Handbook of Vacuum Physics, Volume 3: Technology is a handbook of vacuum physics, with emphasis on the properties of miscellaneous materials such as mica, oils, greases, waxes, and rubber. Accurate modern tables of physical constants, properties of materials, laboratory techniques, and properties of commercial pumps, gauges, and leak detectors are presented. This volume is comprised of 12 chapters and begins with a discussion on pump oils, divided into rotary pump oils and vapor pump oils. The next chapter deals with the properties and applications of greases, including outgassing and vapor pr

  11. COS Ultraviolet Baryon Survey (CUBS) (United States)

    Chen, Hsiao-Wen


    The cosmic star-formation-rate density declines rapidly from z 1.5 to the present day. Observing the co-evolution of galaxies and their surrounding gas during this epoch provides key insights into how galaxy growth is regulated by accretion and outflows. We propose the COS Ultraviolet Baryon Survey (CUBS) project to map gas flows in and out of the circumgalactic medium at intermediate redshifts using absorption line spectroscopy of 15 QSOs at zqso=0.8-1.3. CUBS will bridge the gap between existing efforts at z4 studies in the JWST era, and greatly enhance HST's UV spectroscopic legacy with a three-fold increase in high-quality UV absorption spectra at zqso>0.8. Over the range of z=0.4-0.8, absorption measurements of both low- and high-ions (i.e. C, O, Si, Ne), together with accurate measurements of HI column density from multiple Lyman series transitions, enable robust measurements of the ionization state and metallicity of the gas. All of the proposed QSOs are in the Dark Energy Survey, providing deep, multi-color images of the galactic environments of the absorption systems. We will obtain follow-up spectroscopy of the QSOs and complete spectroscopic redshift surveys of the galaxies in the foreground volume. CUBS will 1) provide a census of the chemical enrichment of the CGM/IGM over cosmic time, 2) assess its relationship to galaxies at various stages of evolution, and 3) inform and refine galactic feedback prescriptions in cosmological simulations. This project exploits a synergy between UV spectroscopy, parallel slitless grism spectroscopy, and ground-based wide-field survey data to advance our understanding of the cosmic evolution of baryonic structures.

  12. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H


    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  13. Angle-resolved photoemission spectroscopy with 9-eV photon-energy pulses generated in a gas-filled hollow-core photonic crystal fiber

    Energy Technology Data Exchange (ETDEWEB)

    Bromberger, H., E-mail:; Liu, H.; Chávez-Cervantes, M.; Gierz, I. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Ermolov, A.; Belli, F.; Abdolvand, A.; Russell, P. St. J.; Travers, J. C. [Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen (Germany); Calegari, F. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Institute for Photonics and Nanotechnologies, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Li, M. T.; Lin, C. T. [Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569 Stuttgart (Germany); Cavalleri, A. [Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg (Germany); Clarendon Laboratory, Department of Physics, University of Oxford, Parks Rd. Oxford OX1 3PU (United Kingdom)


    A recently developed source of ultraviolet radiation, based on optical soliton propagation in a gas-filled hollow-core photonic crystal fiber, is applied here to angle-resolved photoemission spectroscopy (ARPES). Near-infrared femtosecond pulses of only few μJ energy generate vacuum ultraviolet radiation between 5.5 and 9 eV inside the gas-filled fiber. These pulses are used to measure the band structure of the topological insulator Bi{sub 2}Se{sub 3} with a signal to noise ratio comparable to that obtained with high order harmonics from a gas jet. The two-order-of-magnitude gain in efficiency promises time-resolved ARPES measurements at repetition rates of hundreds of kHz or even MHz, with photon energies that cover the first Brillouin zone of most materials.

  14. LEP Vacuum Chamber

    CERN Multimedia


    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  15. The vacuum strikes back

    CERN Multimedia


    "Modern physics has shown that the vacuum, previously thought of as a stated of total nothingness, is really a seething background of virtual particles springing in and out of eixstence until they can seize enough energy to materialize as "real" particles." (1,5 page)

  16. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab


    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  17. ISR vacuum system

    CERN Multimedia

    CERN PhotoLab


    Some of the most important components of the vacuum system are shown. At the left, the rectangular box is a sputter-ion pump inside its bake-out oven. The assembly in the centre includes a sector valve, three roughing valves, a turbomolecular pump, a rotary backing pump and auxiliary equipment. At the right, the small elbow houses a Bayard-

  18. Furnace brazing under partial vacuum (United States)

    Mckown, R. D.


    Brazing furnace utilizing partial-vacuum technique reduces tooling requirements and produces better bond. Benefit in that partial vacuum helps to dissociate metal oxides that inhibit metal flow and eliminates heavy tooling required to hold parts together during brazing.

  19. Tritium handling in vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Gill, J.T. [Monsanto Research Corp., Miamisburg, OH (United States). Mound Facility; Coffin, D.O. [Los Alamos National Lab., NM (United States)


    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  20. Synchrotron-based double imaging photoelectron/photoion coincidence spectroscopy of radicals produced in a flow tube: OH and OD

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Gustavo A.; Tang, Xiaofeng; Gil, Jean-François; Nahon, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Ward, Michael; Batut, Sebastien; Fittschen, Christa [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Taatjes, Craig A.; Osborn, David L. [Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969 (United States); Loison, Jean-Christophe [ISM, Université Bordeaux 1, CNRS, 351 cours de la Libération, 33405 Talence Cedex (France)


    We present a microwave discharge flow tube coupled with a double imaging electron/ion coincidence device and vacuum ultraviolet (VUV) synchrotron radiation. The system has been applied to the study of the photoelectron spectroscopy of the well-known radicals OH and OD. The coincidence imaging scheme provides a high selectivity and yields the spectra of the pure radicals, removing the ever-present contributions from excess reactants, background, or secondary products, and therefore obviating the need for a prior knowledge of all possible byproducts. The photoelectron spectra encompassing the X{sup 3}Σ{sup −} ground state of the OH{sup +} and OD{sup +} cations have been extracted and the vibrational constants compared satisfactorily to existing literature values. Future advantages of this approach include measurement of high resolution VUV spectroscopy of radicals, their absolute photoionization cross section, and species/isomer identification in chemical reactions as a function of time.

  1. The World Space Observatory - Ultraviolet (WSO-UV Space Telescope; Status Update in 2013

    Directory of Open Access Journals (Sweden)

    Ana I. Gómez de Castro


    Full Text Available This is a short primer and a brief update on the status of the World Space Observatory-Ultraviolet (WSO-UV project dated in May 2013. WSO-UV is a 170m primary space telescope equipped for ultraviolet imaging and spectroscopy that will be operational in 2017 hosting an open science program for the world-wide scientic community.

  2. Observation of the Phononic Lamb Shift with a Synthetic Vacuum

    Directory of Open Access Journals (Sweden)

    T. Rentrop


    Full Text Available In contrast to classical empty space, the quantum vacuum fundamentally alters the properties of embedded particles. This paradigm shift allows one to explain the discovery of the celebrated Lamb shift in the spectrum of the hydrogen atom. Here, we engineer a synthetic vacuum, building on the unique properties of ultracold atomic gas mixtures, offering the ability to switch between empty space and quantum vacuum. Using high-precision spectroscopy, we observe the phononic Lamb shift, an intriguing many-body effect originally conjectured in the context of solid-state physics. We find good agreement with theoretical predictions based on the Fröhlich model. Our observations establish this experimental platform as a new tool for precision benchmarking of open theoretical challenges, especially in the regime of strong coupling between the particles and the quantum vacuum.

  3. Nonperturbative QED vacuum birefringence (United States)

    Denisov, V. I.; Dolgaya, E. E.; Sokolov, V. A.


    In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.

  4. Vacuum distillation device

    Energy Technology Data Exchange (ETDEWEB)

    Hamer, J.A.; Burg, C.J. Van Der; Kanbier, D.; Heijden, P. Van Der.


    This invention relates to a vacuum distillation device comprising a vacuum distillation column, a furnace provided with a heat exchange tube, and a connecting conduit between the column and the heat exchange tube. Such a device is used to fractionate a hydrocarbon-containing feed sometimes referred to as long residue. An object of this invention is to provide a vacuum distillation device which allows vaporization of a major part of the feed upstream of the column inlet. To this end, the device according to the invention comprises a vacuum distillation device as described above, in which the inner diameter of the heat exchange tube increases along its length to between 2.4 and 3 times the inner diameter of the tube inlet, and in which the inner diameter of the connecting conduit gradually increases along its length to between 2.5 and 5.4 times the inner diameter of the tube outlet. During normal operation of the device of the invention, only less than 50 wt % of the feed is vaporized in the heat exchange tube in the furnace, and more feed is vaporized in the connecting conduit, so that at the outlet end of the conduit the feed comprises about 0.9 kg vapor per kg of feed. The invention provides improved heat transfer in the heat exchange tubes such that fouling is reduced, consequently more heat can be applied per unit of time in the heat exchange tube. This allows either heating of the feed to a higher temperature or increasing the throughput for the same temperature.


    Directory of Open Access Journals (Sweden)

    Zaid A. Abdulrahman


    Full Text Available Simulated column performance curves were constructed for existing paraffin separation vacuum distillation column in LAB plant (Arab Detergent Company/Baiji-Iraq. The variables considered in this study are the thermodynamic model option, top vacuum pressure, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates composition were constructed. Four different thermodynamic model options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.The simulated results show that about 2% to 8 % of paraffin (C10, C11, C12, & C13 present at the bottom stream which may cause a problem in the LAB plant. The major variations were noticed for the top temperature & the  paraffin weight fractions at bottom section with top vacuum pressure. The bottom temperature above 240 oC is not recommended because the total bottom flow rate decreases sharply, where as  the weight fraction of paraffins decrease slightly. The study gives evidence about a successful simulation with CHEMCAD

  6. Polymer filters for ultraviolet-excited integrated fluorescence sensing (United States)

    Dandin, Marc; Abshire, Pamela; Smela, Elisabeth


    Optical filters for blocking ultraviolet (UV) light were fabricated by doping various polymer hosts with a UV absorbing chromophore. The polymers were polydimethylsiloxane (PDMS), a silicone elastomer frequently used in microfluidics, SU-8, a photopatternable epoxy, and Humiseal 1B66, an acrylic coating used for moisture protection of integrated circuits. The chromophore was 2-(2‧-hydroxy-5‧-methylphenyl) benzotriazole (BTA), which has a high extinction coefficient between 300 nm and 400 nm. We demonstrate filters 5 µm thick that exhibit high ultraviolet rejection (nearly -40 dB at 342 nm) yet pass visible light (near 0 dB above 400 nm), making them ideal for ultraviolet-excited fluorescence sensing within microsystems. The absorbance of the BTA depended on the host polymer. These filters are promising for integrated fluorescence spectroscopy in bioanalytical platforms because they can be patterned by dry etching, molding or exposure to ultraviolet light.

  7. Comprehensive study of solid pharmaceutical tablets in visible, near infrared (NIR), and longwave infrared (LWIR) spectral regions using a rapid simultaneous ultraviolet/visible/NIR (UVN) + LWIR laser-induced breakdown spectroscopy linear arrays detection system and a fast acousto-optic tunable filter NIR spectrometer. (United States)

    Yang, Clayton S C; Jin, Feng; Swaminathan, Siva R; Patel, Sita; Ramer, Evan D; Trivedi, Sudhir B; Brown, Ei E; Hommerich, Uwe; Samuels, Alan C


    This is the first report of a simultaneous ultraviolet/visible/NIR and longwave infrared laser-induced breakdown spectroscopy (UVN + LWIR LIBS) measurement. In our attempt to study the feasibility of combining the newly developed rapid LWIR LIBS linear array detection system to existing rapid analytical techniques for a wide range of chemical analysis applications, two different solid pharmaceutical tablets, Tylenol arthritis pain and Bufferin, were studied using both a recently designed simultaneous UVN + LWIR LIBS detection system and a fast AOTF NIR (1200 to 2200 nm) spectrometer. Every simultaneous UVN + LWIR LIBS emission spectrum in this work was initiated by one single laser pulse-induced micro-plasma in the ambient air atmosphere. Distinct atomic and molecular LIBS emission signatures of the target compounds measured simultaneously in UVN (200 to 1100 nm) and LWIR (5.6 to 10 µm) spectral regions are readily detected and identified without the need to employ complex data processing. In depth profiling studies of these two pharmaceutical tablets without any sample preparation, one can easily monitor the transition of the dominant LWIR emission signatures from coating ingredients gradually to the pharmaceutical ingredients underneath the coating. The observed LWIR LIBS emission signatures provide complementary molecular information to the UVN LIBS signatures, thus adding robustness to identification procedures. LIBS techniques are more surface specific while NIR spectroscopy has the capability to probe more bulk materials with its greater penetration depth. Both UVN + LWIR LIBS and NIR absorption spectroscopy have shown the capabilities of acquiring useful target analyte spectral signatures in comparable short time scales. The addition of a rapid LWIR spectroscopic probe to these widely used optical analytical methods, such as NIR spectroscopy and UVN LIBS, may greatly enhance the capability and accuracy of the combined system for a comprehensive analysis.

  8. Ultraviolet radiation and immunosuppression.

    LENUS (Irish Health Repository)

    Murphy, G M


    Ultraviolet (UV) radiation is a complete carcinogen. The effects of UV radiation are mediated via direct damage to cellular DNA in the skin and suppression of image surveillance mechanisms. In the context of organ transplantation, addiction of drugs which suppress the immune system add greatly to the carcinogenicity of UV radiation. This review considers the mechanisms of such effects.

  9. Ultraviolet fire detector (United States)

    Turnage, J. E.; Linford, R. M. F.; Cornish, S. D.


    System is capable of detecting ultraviolet light emitted by match size flame at distance of 10 ft. System is not affected by high energy or particulate radiation and is therefore particularly suited for applications around nuclear plants and X-ray equipment.

  10. NMR and Chemometric Characterization of Vacuum Residues and Vacuum Gas Oils from Crude Oils of Different Origin

    Directory of Open Access Journals (Sweden)

    Jelena Parlov Vuković


    Full Text Available NMR spectroscopy in combination with statistical methods was used to study vacuum residues and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly, principal component analysis on complete spectra was used to perform classification of samples and clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively predict the composition of asphaltenes, principal component regression models using areas of resonance signals spaned by 11 frequency bins of the 1H NMR spectra were build. The first 5 principal components accounted for more than 94 % of variations in the input data set and coefficient of determination for correlation between measured and predicted values was R2 = 0.7421. Although this value is not significant, it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments were used to assess the composition and structural properties of asphaltenes in a selected crude oil and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing in size and interactions they formed. The obtained results have shown that NMR techniques in combination with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in more details composition, structure and properties of these complex molecular systems.

  11. Deep-ultraviolet quantum interference metrology with ultrashort laser pulses

    NARCIS (Netherlands)

    Witte, S.; Zinkstok, R.T.; Ubachs, W.M.G.; Hogervorst, W.; Eikema, K.S.E.


    Precision spectroscopy at ultraviolet and shorter wavelengths has been hindered by the poor access of narrow-band lasers to that spectral region. We demonstrate high-accuracy quantum interference metrology on atomic transitions with the use of an amplified train of phase-controlled pulses from a

  12. The effect of excitation wavelength on plasma spectrum of metals in vacuum condition (United States)

    Hidayah, A. N.; Suliyanti, M. M.; Isnaeni


    Pure metals Aluminum (Al), Copper (Cu) and Brass (CuZn) have been detected using laser-induced plasma spectroscopy technique using nanosecond laser. A Q-switch pulsed Nd:YAG laser operating at infrared (1064 nm), visible (532 nm) and ultraviolet (355 nm) wavelengths have been used. The energy laser used was 12 mJ and the experiment was carried out in vacuum condition (5 Torr). The plasma generated by a focused Nd:YAG laser beam was detected by a spectrometer to identify trace elements quantitatively. The result of quantitative trace element of pure metals at three different wavelengths gave the different results. Al metal excited by 355 nm, 532 nm and 1064 nm wavelengths has 5, 2 and 13 Al emission peaks, respectively. Whereas the analysis of Cu showed 5, 7 and 6 emission peaks upon excitation by 355 nm, 532 nm and 1064 nm wavelengths, respectively. Finally, CuZn metal produced 7 Cu lines and 2 Zn lines upon excitation by 355 nm wavelength, 8 Cu lines and 1 Zn line when excited by 532 nm wavelength, and 8 Cu lines and 3 Zn lines when excited by 1064 nm wavelength.

  13. Threshold photoelectron spectroscopy of the imidogen radical

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Gustavo A., E-mail: [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Gans, Bérenger [Institut des Sciences Moléculaires d’Orsay, Univ Paris-Sud, CNRS, Bât 210, Univ Paris-Sud, 91405 Orsay Cedex (France); Tang, Xiaofeng [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Ward, Michael; Batut, Sébastien [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Nahon, Laurent [Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette (France); Fittschen, Christa [PC2A, Université de Lille 1, UMR CNRS-USTL 8522, Cité Scientifique Bât. C11, F-59655 Villeneuve d’Ascq (France); Loison, Jean-Christophe [ISM, Université de Bordeaux, CNRS, 351 cours de la Libération, 33405 Talence Cedex (France)


    We present the threshold photoelectron spectroscopy of the imidogen radical (NH) recorded in the photon energy region up to 1 eV above its first ionization threshold. The radical was produced by reaction of NH{sub 3} and F in a microwave discharge flow-tube and photoionized using vacuum ultraviolet (VUV) synchrotron radiation. A double imaging coincidence spectrometer was used to record mass-selected spectra and avoid contributions from the byproducts present in the reactor and background gas. The energy region includes the ground X{sup +2}Π and first electronically excited a{sup +4}Σ{sup −} states of NH{sup +}. Strong adiabatic transitions and weak vibrational progressions up to v{sup +} = 2 are observed for both electronic states. The rotational profile seen in the origin band has been modeled using existing neutral and cationic spectroscopic constants leading to a precise determination of the adiabatic ionization energy at 13.480 ± 0.002 eV.

  14. The vacuum platform (United States)

    McNab, A.


    This paper describes GridPP’s Vacuum Platform for managing virtual machines (VMs), which has been used to run production workloads for WLCG and other HEP experiments. The platform provides a uniform interface between VMs and the sites they run at, whether the site is organised as an Infrastructure-as-a-Service cloud system such as OpenStack, or an Infrastructure-as-a-Client system such as Vac. The paper describes our experience in using this platform, in developing and operating VM lifecycle managers Vac and Vcycle, and in interacting with VMs provided by LHCb, ATLAS, ALICE, CMS, and the GridPP DIRAC service to run production workloads.

  15. Extending Tabletop XUV Spectroscopy to the Liquid Phase to Examine Transition Metal Catalysts (United States)

    Benke, Kristin; Ryland, Elizabeth S.; Vura-Weis, Josh


    M-edge spectroscopy of first row transition metals (3p to 3d excitation) is the low energy analogue of more well-known K- and L-edge spectroscopy, but can be implemented without the use of a synchrotron. Instead, M-edge spectroscopy can be performed as a tabletop method, relying on high harmonic generation (HHG) to produce ultrashort (˜ 20 fs) pulses of extreme ultraviolet (XUV) light in the range of 10-100s of eV. We have shown tabletop M-edge spectroscopy to be a valuable tool in determining the electronic structure of metal-centered coordination complexes and have demonstrated its capacity to yield element-specific information about a compound's oxidation state, spin state, and ligand field. The power of this technique to distinguish these features makes it a promising addition to the arsenal of methods used to study metal-centered catalysts. A catalytic reaction can be initiated photochemically and the XUV probe can be used to track oxidative and structural changes to identify the key intermediates. Until recently tabletop XUV spectroscopy has been performed on thin film samples, but in order to examine homogeneous catalysis, the technique must be adapted to look at samples in the liquid phase. The challenges of adapting tabletop XUV spectroscopy to the liquid phase lie in the lower attenuation length of XUV light compared to soft and hard x-rays and the lower flux compared to synchrotron methods. As a result, the sample must be limited to a sub-micron thickness as well as isolated from the vacuum environment required for x-ray spectroscopy. I am developing a liquid flow cell that relies on confining the sample between two x-ray transmissive SiN membranes, as has been demonstrated for use at synchrotrons, but adapted to the unique difficulties encountered in tabletop XUV spectroscopy.

  16. R&D ERL: Vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.


    The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The

  17. Of vacuum and gas

    CERN Multimedia

    Katarina Anthony


    A new LHCb programme is delving into uncharted waters for the LHC: exploring how protons interact with noble gases inside the machine pipe. While, at first glance, it may sound risky for the overall quality of the vacuum in the machine, the procedure is safe and potentially very rich in rewards. The results could uncover the high-energy helium-proton cross-section (with all the implications thereof), explore new boundaries of the quark-gluon plasma and much more.   As the beam passes through LHCb, interactions with neon gas allow the experiment to measure the full beam profile. In this diagram, beam 1 (blue) and beam 2 (red) are measured by the surrounding VELO detector. It all begins with luminosity. In 2011, LHCb set out to further improve its notoriously precise measurements of the beam profile, using the so-called Beam-Gas Imaging (BGI) method. BGI does exactly what it says on the tin: a small amount of gas is inserted into the vacuum, increasing the rate of collisions around the interaction ...

  18. LHC vacuum system

    CERN Document Server

    Gröbner, Oswald


    The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

  19. Far ultraviolet instrument technology (United States)

    Paxton, Larry J.; Schaefer, Robert K.; Zhang, Yongliang; Kil, Hyosub


    The far ultraviolet (FUV) spectral range (from about 115 nm to 180 nm) is one of the most useful spectral regions for characterizing the upper atmosphere (thermosphere and ionosphere). The principal advantages are that there are FUV signatures of the major constituents of the upper atmosphere as well as the signatures of the high-latitude energy inputs. Because of the absorption by thermospheric O2, the FUV signatures are seen against a "black" background, i.e., one that is not affected by ground albedo or clouds and, as a consequence, can make useful observations of the aurora during the day or when the Moon is above the horizon. In this paper we discuss the uses of FUV remote sensing, summarize the various techniques, and discuss the technological challenges. Our focus is on a particular type of FUV instrument, the scanning imaging spectrograph or SIS: an instrument exemplified by the Defense Meteorological Satellite Program Special Sensor Ultraviolet Imager and Thermosphere Ionosphere Mesosphere Energetics and Dynamics Global Ultraviolet Imager. The SIS combines spatial imaging of the disk with limb profiles as well as spectral information at each point in the scan.

  20. Vacuum science, technology, and applications

    CERN Document Server

    Naik, Pramod K


    Vacuum plays an important role in science and technology. The study of interaction of charged particles, neutrals and radiation with each other and with solid surfaces requires a vacuum environment for reliable investigations. Vacuum has contributed immensely to advancements made in nuclear science, space, metallurgy, electrical/electronic technology, chemical engineering, transportation, robotics and many other fields. This book is intended to assist students, scientists, technicians and engineers to understand the basics of vacuum science and technology for application in their projects. The fundamental theories, concepts, devices, applications, and key inventions are discussed.

  1. Laser target using continuous supersonic jet in vacuum


    Ogata Yujin; Takahashi Kazumasa; Kuwabara Hajime; Nakajima Mitsuo; Horioka Kazuhiko


    For an extreme ultraviolet (EUV) light source, Sn plasmas, which can produce a strong radiation with high conversion efficiency at 13.5 nm, attract attention. The purpose of this study is to establish technology to form and recover a tin vapor supersonic jet in vacuum and to make clear the interaction between the supersonic free jet and an incident laser. In order to make the tin vapor, a tantalum crucible is inductively heated up and the radiation loss is compared with the input energy. We o...

  2. Photoelectron spectroscopy of a series of acetate and propionate esters (United States)

    Śmiałek, Małgorzata A.; Guthmuller, Julien; MacDonald, Michael A.; Zuin, Lucia; Delwiche, Jacques; Hubin-Franskin, Marie-Jeanne; Lesniewski, Tadeusz; Mason, Nigel J.; Limão-Vieira, Paulo


    The electronic state and photoionization spectroscopy of a series of acetate esters: methyl acetate, isopropyl acetate, butyl acetate and pentyl acetate as well as two propionates: methyl propionate and ethyl propionate, have been determined using vacuum-ultraviolet photoelectron spectroscopy. These experimental investigations are complemented by ab initio calculations. The measured first adiabatic and vertical ionization energies were determined as: 10.21 and 10.45 eV for methyl acetate, 9.99 and 10.22 eV for isopropyl acetate, 10.07 and 10.26 eV for butyl acetate, 10.01 and 10.22 eV for pentyl acetate, 10.16 and 10.36 eV for methyl propionate and 9.99 and 10.18 eV for ethyl propionate. For the four smaller esters vibrational transitions were calculated and compared with those identified in the photoelectron spectrum, revealing the most distinctive ones to be a Csbnd O stretch combined with a Cdbnd O stretch. The ionization energies of methyl and ethyl esters as well as for a series of formates and acetates were compared showing a clear dependence of the value of the ionization energy on the size of the molecule with very little influence of its conformation.

  3. Sealing Materials for Use in Vacuum at High Temperatures (United States)

    Pettit, Donald R.; Camarda, Charles J.; Lee Vaughn, Wallace


    Sealing materials that can be applied and left in place in vacuum over a wide range of temperatures (especially temperatures of a few thousand degrees Celsius) have been conceived and investigated for potential utility in repairing thermal-protection tiles on the space shuttles in orbit before returning to Earth. These materials are also adaptable to numerous terrestrial applications that involve vacuum processing and/or repair of structures that must withstand high temperatures. These materials can be formulated to have mechanical handling characteristics ranging from almost freely flowing liquid-like consistency through paste-like consistency to stiff puttylike consistency, and to retain these characteristics in vacuum until heated to high curing temperatures. A sealing material of this type can be formulated to be used in any of several different ways for example, to be impregnated into a high-temperature-fabric patch, impregnated into a high-temperature-fabric gasket for sealing a patch, applied under a patch, or applied alone in the manner of putty or wallboard compound. The sealing material must be formulated to be compatible with, and adhere to, the structural material(s) to be repaired. In general, the material consists of a vacuum-compatible liquid containing one or more dissolved compound(s) and/or mixed with suspended solid particles. Depending on the intended application, the liquid can be chosen to be of a compound that can remain in place in vacuum for a time long enough to be useful, and/or to evaporate or decompose in a controlled way to leave a useful solid residue behind. The evaporation rate is determined by proper choice of vapor pressure, application of heat, and/or application of ultraviolet light or other optical radiation. The liquid chosen for the original space shuttle application is a commercial silicone vacuum-pump oil.

  4. Vacuum deposited polymer/metal films for optical applications (United States)

    Affinito, J. D.; Martin, P. M.; Gross, M. E.; Coronado, C.; Greenwell, E.


    Vacuum deposited Polymer/Silver/Polymer reflectors and Tantalum/Polymer/Aluminum Fabry-Perot interference filters were fabricated in a vacuun web coating operation on polyester substrates with a new, high speed deposition process. Reflectivities were measured in the wavelength range from 0.3 to 0.8(mu)m. This new vacuum processing technique has been shown to be capable of deposition line speeds in excess of 500 linear meters/minute. Central to this technique is a new position process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process -- for Polymer Multi-Layer. Also, vacuum deposited, index matched, polymer/CaF(sub 2) composites were fabricated from monomer slurries that were subsequently cured with LTV light. This second technique is called the Liquid Multi-Layer (or LML) process. Each of these polymer processes is compatible with each other and with conventional vacuum deposition processes such as sputtering or evaporation.

  5. Vacuum energy sequestering and graviton loops


    Kaloper, Nemanja; Padilla, Antonio


    We recently formulated a local mechanism of vacuum energy sequester. This mechanism automatically removes all matter loop contributions to vacuum energy from the stress energy tensor which sources the curvature. Here we adapt the local vacuum energy sequestering mechanism to also cancel all the vacuum energy loops involving virtual gravitons, in addition to the vacuum energy generated by matter fields alone.

  6. Calibration of the Swift-UVOT ultraviolet and visible grisms


    Kuin, N. P. M.; Landsman, W.; Breeveld, A. A.; Page, M. J.; Lamoureux, H.; James, C.; Mehdipour, M.; Still, M.; Yershov, V.; Brown, P.J.; Carter, M; Mason, K. O.; Kennedy, T.; Marshall, F.; Roming, P. W. A.


    We present the calibration of the Swift Ultraviolet and Optical Telescope (UVOT ) grisms, of which there are two, providing low-resolution field spectroscopy in the ultraviolet and optical bands, respectively. The UV grism covers the range λ1700–5000 Å with a spectral resolution (λ/Δλ) of 75 at λ2600 Å for source magnitudes of u=10–16 mag, while the visible grism covers the range λ2850–6600 Å with a spectral resolution of 100 at λ4000 Å for source magnitudes of b=12–17 mag. This calibration e...


    Price, G.W.


    A protector device is described for use in controlling the pressure within a cyclotron. In particular, an electrical circuit functions to actuate a vacuum pump when a predetermined low pressure is reached and disconnect the pump when the pressure increases abcve a certain value. The principal feature of the control circuit lies in the use of a voltage divider network at the input to a relay control tube comprising two parallel, adjustable resistances wherein one resistor is switched into the circuit when the relay connects the pump to a power source. With this arrangement the relay is energized at one input level received from a sensing element within the cyclotron chamber and is de-energized when a second input level, representing the higher pressure limit, is reached.

  8. Synchrotron radiation circular dichroism spectroscopy of proteins and applications in structural and functional genomics. (United States)

    Miles, Andrew J; Wallace, B A


    The technique of Synchrotron Radiation Circular Dichroism (SRCD) spectroscopy and its advantages over conventional circular dichroism spectroscopy are described in this tutorial review, as well as recent applications of the technique in structural and functional genomics. Circular dichroism (CD) spectroscopy is a well-established method in biological chemistry and structural biology, but its utility can be limited by the low flux of the light source in the far ultraviolet and vacuum ultraviolet wavelength regions in conventional CD instruments. The development of synchrotron radiation circular dichroism (SRCD), using the intense light of a synchrotron beam, has greatly expanded the utility of the method, especially as a tool for both structural and functional genomics. These applications take advantage of the enhanced features of SRCD relative to conventional CD: the ability to measure lower wavelength data containing more electronic transitions and hence more structural information, the higher signal-to-noise hence requiring smaller samples, the higher intensity enabling measurements in absorbing buffers and in the presence of lipids and detergents, and the ability to do faster measurements enabling high throughput and time-resolved spectroscopy.This article discusses recent developments in SRCD instrumentation, software, sample preparation and methods of analyses, with particular emphasis on their applications to the study of proteins. These advances have led to new applications in structural genomics (SG), including the potential for fold recognition as a means of target selection and the examination of membrane proteins, a class of proteins usually excluded from SG programmes. Other SG uses include detection of macromolecular interactions as a screen for complex formation, and examination of glycoproteins and sugar components. In functional genomics (FG) new applications include screening for ligand binding as a means of identifying function, and examination of

  9. Abdominal intrauterine vacuum aspiration. (United States)

    Tjalma, W A A


    Evaluating and "cleaning" of the uterine cavity is probably the most performed operation in women. It is done for several reasons: abortion, evaluation of irregular bleeding in premenopausal period, and postmenopausal bleeding. Abortion is undoubtedly the number one procedure with more than 44 million pregnancies terminated every year. This procedure should not be underestimated and a careful preoperative evaluation is needed. Ideally a sensitive pregnancy test should be done together with an ultrasound in order to confirm a uterine pregnancy, excluding extra-uterine pregnancy, and to detect genital and/or uterine malformations. Three out of four abortions are performed by surgical methods. Surgical methods include a sharp, blunt, and suction curettage. Suction curettage or vacuum aspiration is the preferred method. Despite the fact that it is a relative safe procedure with major complications in less than one percent of cases, it is still responsible for 13% of all maternal deaths. All the figures have not declined in the last decade. Trauma, perforation, and bleeding are a danger triage. When there is a perforation, a laparoscopy should be performed immediately, in order to detect intra-abdominal lacerations and bleeding. The bleeding should be stopped as soon as possible in order to not destabilize the patient. When there is a perforation in the uterus, this "entrance" can be used to perform the curettage. This is particularly useful if there is trauma of the isthmus and uterine wall, and it is difficult to identify the uterine canal. A curettage is a frequent performed procedure, which should not be underestimated. If there is a perforation in the uterus, then this opening can safely be used for vacuum aspiration.


    NARCIS (Netherlands)


    A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at

  11. Vacuum Technology for Superconducting Devices

    CERN Document Server

    Chiggiato, P


    The basic notions of vacuum technology for superconducting applications are presented, with an emphasis on mass and heat transport in free molecular regimes. The working principles and practical details of turbomolecular pumps and cryopumps are introduced. The specific case of the Large Hadron Collider’s cryogenic vacuum system is briefly reviewed.

  12. Ultraviolet Communication for Medical Applications (United States)


    AWARD NUMBER: W81XWH-12-C-0043 TITLE: Ultraviolet Communication for Medical Applications PRINCIPAL INVESTIGATOR: Lee Cross CONTRACTING...5a. CONTRACT NUMBER W81XWH-12-C-0043 Ultraviolet Communication for Medical Applications 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...contains color. 14. ABSTRACT Under this Phase II SBIR effort, Directed Energy Inc.’s (DEI) proprietary ultraviolet (UV) emitters and the best

  13. Vacuum fiber-fiber coupler (United States)

    Heinrici, Axel; Bjelajac, Goran; Jonkers, Jeroen; Jakobs, Stefan; Olschok, Simon; Reisgen, Uwe


    Research and development carried out by the ISF Welding and Joining Institute of RWTH Aachen University has proven that combining high power laser and low vacuum atmosphere provides a welding performance and quality, which is comparable to electron beam welding. The developed welding machines are still using a beam forming which takes place outside the vacuum and the focusing laser beam has to be introduced to the vacuum via a suitable window. This inflexible design spoils much of the flexibility of modern laser welding. With the target to bring a compact, lightweight flying optics with flexible laser transport fibers into vacuum chambers, a high power fiber-fiber coupler has been adapted by II-VI HIGHYAG that includes a reliable vacuum interface. The vacuum-fiber-fiber coupler (V-FFC) is tested with up to 16 kW sustained laser power and the design is flexible in terms of a wide variety of laser fiber plug systems and vacuum flanges. All that is needed to implement the V-FFC towards an existing or planned vacuum chamber is an aperture of at least 100 mm (4 inch) diameter with any type of vacuum or pressure flange. The V-FFC has a state-of-the-art safety interface which allows for fast fiber breakage detection for both fibers (as supported by fibers) by electric wire breakage and short circuit detection. Moreover, the System also provides connectors for cooling and electric signals for the laser beam optics inside the vacuum. The V-FFC has all necessary adjustment options for coupling the laser radiation to the receiving fiber.

  14. Transparent ultraviolet photovoltaic cells. (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen


    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  15. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system. (United States)


    ... 49 Transportation 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems...

  16. Ultraviolet damage in solar cell assemblies with various UV filters (United States)

    Meulenberg, A., Jr.


    Ultraviolet damage to the new violet and non-reflective type solar cell assemblies, was studied, and potential advantages of using coverslides with no filters or filters with cut-off wavelengths below 0.35 micron were determined. The experiments consisted of three types of tests on fused silica coverslides with 0.35- and 0.30-micron cut-off filters and no cut-off filters, as well as on ceria-doped microsheet coverslides. Ultraviolet irradiation for over 1500 hours at one sun conditions (AMO) was carried out under vacuum of about 1 million torr. Nearly identical results for non-reflective type cells with 0.35-micro cut-off filters or ceria-doped coverslides were obtained. The 0.30-um filtered cell shows greater than average degradation. The unfiltered cell shows an abrupt drop in the first 20 UVSH and very little subsequent degradation.

  17. Micrometer-thickness liquid sheet jets flowing in vacuum (United States)

    Galinis, Gediminas; Strucka, Jergus; Barnard, Jonathan C. T.; Braun, Avi; Smith, Roland A.; Marangos, Jon P.


    Thin liquid sheet jet flows in vacuum provide a new platform for performing experiments in the liquid phase, for example X-ray spectroscopy. Micrometer thickness, high stability, and optical flatness are the key characteristics required for successful exploitation of these targets. A novel strategy for generating sheet jets in vacuum is presented in this article. Precision nozzles were designed and fabricated using high resolution (0.2 μm) 2-photon 3D printing and generated 1.49 ± 0.04 μm thickness, stable, and <λ /20-flat jets in isopropanol under normal atmosphere and under vacuum at 5 × 10-1 mbar. The thin sheet technology also holds great promise for advancing the fields of high harmonic generation in liquids, laser acceleration of ions as well as other fields requiring precision and high repetition rate targets.

  18. Calibration of windowless photodiode for extreme ultraviolet pulse energy measurement. (United States)

    Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav; Frolov, Oleksandr


    For energy measurement of extreme ultraviolet pulses, no universal commercially available device is available. Therefore, a co-axial setup of a vacuum photodiode was developed and tested. First its unsuccessful calibration at the National Institute of Standards and Technology (USA) is mentioned. Then our own single-wavelength (46.9 nm) calibration procedure is described in detail. It is based on tabulated photoemission efficiency and on measured (1) anode collection efficiency, (2) attenuation of Al filters, and (3) attenuation of measuring cables. Some other relevant attenuating factors are also taken into account.


    Directory of Open Access Journals (Sweden)

    E. D. Chertov


    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  20. Experimental tests of vacuum energy

    CERN Multimedia

    CERN. Geneva


    While the current vacuum energy of the Universe is very small, in our standard cosmological picture it has been much larger at earlier epochs. We try to address the question of what are possible ways to try to experimentally verify this. One direction is to look for systems where vacuum energy constitutes a non-negligible fraction of the total energy, and study the properties of those. Another possibility is to focus on the epochs around cosmic phase transitions, when the vacuum energy is of the same order as the total energy. Along these lines we investigate properties of neutron stars and the imprint of phase transitions on primordial gravitational waves.

  1. Alumina barrier for vacuum brazing (United States)

    Beuyukian, C. S.


    Heating platens of vacuum-brazing press will not stick to workpiece if aluminum oxide "paper" is interposed. Paper does not disintegrate in press, will not contaminate braze alloy, and helps form smoothly contoured, regular fillet at brazed edges.

  2. [Endoscopic vacuum-assisted closure]. (United States)

    Wedemeyer, J; Lankisch, T


    Anastomotic leakage in the upper and lower intestinal tract is associated with high morbidity and mortality. Within the last 10 years endoscopic treatment options have been accepted as sufficient treatment option of these surgical complications. Endoscopic vacuum assisted closure (E-VAC) is a new innovative endoscopic therapeutic option in this field. E-VAC transfers the positive effects of vacuum assisted closure (VAC) on infected cutaneous wounds to infected cavities that can only be reached endoscopically. A sponge connected to a drainage tube is endoscopically placed in the leakage and a continuous vacuum is applied. Sponge and vacuum allow removal of infected fluids and promote granulation of the leakage. This results in clean wound grounds and finally allows wound closure. Meanwhile the method was also successfully used in the treatment of necrotic pancreatitis.


    Directory of Open Access Journals (Sweden)

    André Alexandrino Lotto


    Full Text Available This work aims to investigate the phosphorus removal by vacuum from metallurgical grade silicon (MGSi (98.5% to 99% Si. Melting experiments were carried out in a vacuum induction furnace, varying parameters such as temperature, time and relation area exposed to the vacuum / volume of molten silicon. The results of chemical analysis were obtained by inductively coupled plasma (ICP, and evaluated based on thermodynamic and kinetic aspects of the reaction of vaporization of the phosphorus in the silicon. The phosphorus was decreased from 33 to approximately 1.5 ppm after three hours of vacuum treatment, concluding that the evaporation step is the controlling step of the process for parameters of temperature, pressure and agitation used and refining by this process is technically feasible.

  4. Vacuum production; Produccion de vacio

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, J. L. de


    Since the advent of ultra high vacuum in 1958 has been a great demand for new as means of production and to meet the process needs to be done: industry heavy, high technology and space research areas, large accelerator systems particles or nuclear fusion. In this paper we explore the modern media production: dry vacuum pumps, turbo pumps, pump status diffusion ion pumps and cryopumps. (Author)

  5. Edge conduction in vacuum glazing

    Energy Technology Data Exchange (ETDEWEB)

    Simko, T.M.; Collins, R.E. [Sydney Univ., NSW (Australia). Dept. of Applied Physics; Beck, F.A.; Arasteh, D. [Lawrence Berkeley Lab., CA (United States)


    Vacuum glazing is a form of low-conductance double glazing using in internal vacuum between the two glass sheets to eliminate heat transport by gas conduction and convection. An array of small support pillars separates the sheets; fused solder glass forms the edge seal. Heat transfer through the glazing occurs by radiation across the vacuum gap, conduction through the support pillars, and conduction through the bonded edge seal. Edge conduction is problematic because it affects stresses in the edge region, leading to possible failure of the glazing; in addition, excessive heat transfer because of thermal bridging in the edge region can lower overall window thermal performance and decrease resistance to condensation. Infrared thermography was used to analyze the thermal performance of prototype vacuum glazings, and, for comparison, atmospheric pressure superwindows. Research focused on mitigating the edge effects of vacuum glazings through the use of insulating trim, recessed edges, and framing materials. Experimentally validated finite-element and finite-difference modeling tools were used for thermal analysis of prototype vacuum glazing units and complete windows. Experimental measurements of edge conduction using infrared imaging were found to be in good agreement with finite-element modeling results for a given set of conditions. Finite-element modeling validates an analytic model developed for edge conduction.

  6. Vacuum-assisted cesarean section

    Directory of Open Access Journals (Sweden)

    McQuivey RW


    Full Text Available Ross W McQuivey,1 Jon E Block2 1Clinical Innovations, Salt Lake City, UT, 2Independent consultant, San Francisco, CA, USA Abstract: There has been a dramatic rise in the frequency of cesarean sections, surpassing 30% of all deliveries in the US. This upsurge, coupled with a decreasing willingness to allow vaginal birth after cesarean section, has resulted in an expansion of the use of vacuum assistance to safely extract the fetal head. By avoiding the use of a delivering hand or forceps blade, the volume being delivered through the uterine incision can be decreased when the vacuum is used properly. Reducing uterine extensions with their associated complications (eg, excessive blood loss in difficult cases is also a theoretical advantage of vacuum delivery. Maternal discomfort related to excessive fundal pressure may also be lessened. To minimize the risk of neonatal morbidity, proper cup placement over the “flexion point” remains essential to maintain vacuum integrity and reduce the chance of inadvertent detachment and uterine extensions. Based on the published literature and pragmatic clinical experience, utilization of the vacuum device is a safe and effective technique to assist delivery during cesarean section. Keywords: cesarean section, vacuum, forceps, birth, delivery

  7. Technical specification for vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, J. (ed.)


    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10/sup -5/ to 10/sup -11/ Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components. (LEW)

  8. SYNERGY: an Explorer mission concept for a next-generation ultraviolet survey (United States)

    MacKenty, John W.; Tumlinson, Jason; Arenberg, Jonathan W.; Elder, Craig; Gunderson, Adam; Warwick, Steven; O'Connell, Terri; Wong, Carlton


    Synergy is an Explorer class mission concept to obtain a large-area, multi-tier near-ultraviolet sky survey with lowresolution, spatially resolved slitless spectroscopy (R = 200-600) and simultaneous arc-second imaging between 210-320 nm. It's Wide and Deep surveys will examine the co-evolution of more than 200 million galaxies, 500,000 AGN, and 30,000 gas halos between 0.8 z z = 2 require ultraviolet observations.

  9. Microbiology and Biodegradation: Deep Ultraviolet Microscopy for the Detection, Quantification, and Characterization of Microbes (United States)


    Approved for Public Release; Distribution Unlimited Final Report: 14.3 Microbiology and Biodegradation: Deep Ultraviolet Microscopy for the Detection...Fluroesence; Raman Spectroscopy; Microbiology REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO...14.3 Microbiology and Biodegradation: Deep Ultraviolet Microscopy for the Detection, Quantification, and Characterization of Microbes Report Title


    Life on Earth has evolved adaptations to many environmental stresses over the epochs. One consistent stress has been exposure to ultraviolet radiation. In response to UVR organisms have adapted myriad responses; behavioral, morphological and physiological. Behaviorally, some orga...

  11. Vacuum-deposited polymer/silver reflector material (United States)

    Affinito, John D.; Martin, Peter M.; Gross, Mark E.; Bennett, Wendy D.


    Weatherable, low cost, front surface, solar reflectors on flexible substrates would be highly desirable for lamination to solar concentrator panels. The method to be described in this paper may permit such reflector material to be fabricated for less the 50$CNT per square foot. Vacuum deposited Polymer/Silver/Polymer reflectors and Fabry-Perot interference filters were fabricated in a vacuum web coating operation on polyester substrates. Reflectivities were measured in the wavelength range from .4 micrometers to .8 micrometers . It is hoped that a low cost substrate can be used with the substrate laminated to the concentrator and the weatherable acrylic polymer coating facing the sun. This technique should be capable of deposition line speeds approaching 1500 linear feet/minute2. Central to this technique is a new vacuum deposition process for the high rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high speed polymer film deposition process has been named the PML process- for Polymer Multi- Layer.

  12. Stable, high quantum efficiency silicon photodiodes for vacuum-UV applications (United States)

    Korde, Raj; Canfield, L. Randall; Wallis, Brad


    Silicon photodiodes have been developed by defect-free phosphorus diffusion having practically no carrier recombination at the SiSiO2 interface or in the front diffused region. The quantum efficiency of these photodiodes was found to be around 120 percent at 100 nm. Unlike the previously tested silicon photodiodes, the developed photodiodes exhibit extremely stable quantum efficiency over extended periods of time. The possibility of using these photodiodes as vacuum ultraviolet detector standards is being currently investigated.

  13. Accurate Lifetimes and Absolute Transition Rates for Ultraviolet Transitions from 3D5(4G) 4P and 3D5(4P) 4P levels in MN II (United States)

    Kling, Rainer; Schnabel, Roman; Griesmann, Ulf


    A recently developed, laser-induced fluorescence technique was used to measure the lifetimes of 14 3d5(4G)4p and 3d5(4P)4p levels in the Mn+ ion. Branching fractions for electric dipole transitions from these levels were measured with a vacuum ultraviolet Fourier transform spectrometer, using a hollow-cathode lamp and a Penning discharge source. Based on these new measurements, absolute electric dipole transition rates for about 170 spectral lines in the ultraviolet and vacuum ultraviolet were determined. The uncertainty of the transition rates is less than 5% for the strong transitions.

  14. Tautomerization of Thymine Using Ultraviolet Light. (United States)

    Vinje, Jakob; Falck, Merete; Mazzola, Federico; Cooil, Simon Phillip; Koch, Henrik; Høyvik, Ida-Marie; Wells, Justin


    Ultraviolet-light-induced changes to the nucleobase thymine deposited onto a MoS2 surface were studied using photoelectron spectroscopy and first-principles calculations. These measurements suggest changes in the molecular structure indicated by changes in core electron binding energies. The experimental work has been interpreted by means of ab initio calculations using coupled cluster singles and doubles (CCSD) linear response theory. Contrary to the expected behavior, i.e., the dimerization of two thymine molecules into a pyrimidine dimer, a shift between two tautomeric forms was observed upon UV-exposure. Exposure to ionizing radiation is known to induce damage in many biological molecules, and the present work gives additional insight into its effects on thymine, the interactions of the molecules, and finally how certain UV photoproducts may be avoided.

  15. 21 CFR 872.6350 - Ultraviolet detector. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultraviolet detector. 872.6350 Section 872.6350...) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6350 Ultraviolet detector. (a) Identification. An ultraviolet detector is a device intended to provide a source of ultraviolet light which is used...

  16. Ultraviolet photovoltaics: Share the spectrum (United States)

    Milliron, Delia J.


    Electrically controlled windows require power to switch between transparent and tinted states. Now, an ultraviolet light-harvesting solar cell can power smart windows without compromising their control over heat and light.

  17. Ultraviolet radiation in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Taalas, P.; Koskela, T.; Damski, J.; Supperi, A. [Finnish Meteorological Inst., Helsinki (Finland). Section of Ozone and UV Research; Kyroe, E. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory


    Solar ultraviolet radiation is damaging for living organisms due to its high energy pro each photon. The UV radiation is often separated into three regions according to the wavelength: UVC (200-280 nm), UVB (280-320 nm) and UVA (320-400 nm). The most hazardous part, UVC is absorbed completely in the upper atmosphere by molecular oxygen. UVB radiation is absorbed by atmospheric ozone partly, and it is reaching Earth`s surface, as UVA radiation. Besides atmospheric ozone, very important factors in determining the intensity of UVB radiation globally are the solar zenith angle and cloudiness. It may be calculated from global ozone changes that the clear-sky UVB doses may have enhanced by 10-15 % during spring and 5-10 % during summer at the latitudes of Finland, following the decrease of total ozone between 1979-90. The Finnish ozone and UV monitoring activities have become a part of international activities, especially the EU Environment and Climate Programme`s research projects. The main national level effort has been the Finnish Academy`s climatic change programme, SILMU 1990-95. This presentation summarises the scientific results reached during the SILMU project

  18. Solar ultraviolet radiation cataract. (United States)

    Löfgren, Stefan


    Despite being a treatable disease, cataract is still the leading cause for blindness in the world. Solar ultraviolet radiation is epidemiologically linked to cataract development, while animal and in vitro studies prove a causal relationship. However, the pathogenetic pathways for the disease are not fully understood and there is still no perfect model for human age related cataract. This non-comprehensive overview focus on recent developments regarding effects of solar UV radiation wavebands on the lens. A smaller number of fundamental papers are also included to provide a backdrop for the overview. Future studies are expected to further clarify the cellular and subcellular mechanisms for UV radiation-induced cataract and especially the isolated or combined temporal and spatial effects of UVA and UVB in the pathogenesis of human cataract. Regardless of the cause for cataract, there is a need for advances in pharmaceutical or other treatment modalities that do not require surgical replacement of the lens. Copyright © 2016. Published by Elsevier Ltd.

  19. Electron energy loss spectroscopy (EELS) of organic molecules in ...

    Indian Academy of Sciences (India)

    India. Abstract. An indigenous electron energy loss spectrometer has been designed and fabricated for the study of free molecules. The spectrometer enables the recording of - low-resolution electronic spectra of molecules in the vapour phase with ready access to the vacuum ultraviolet region. Electron energy loss spectra ...

  20. Luminescence spectroscopy of quantum cutting phosphors : materials, measurements and mechanisms

    NARCIS (Netherlands)

    Vergeer, Peter


    The industrial drive for this research is to find new phosphors for application in mercury-free fluorescent lamps and plasma display panels. The vacuum-ultraviolet (VUV) excitation light that is used in these devices allows for the use of phosphors that show emission of two photons for each photon

  1. RFQ Vacuum brazing at CERN

    CERN Document Server

    Mathot, S


    The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The RFQ modules brazed at CERN are made of four 100 or 120 cm long vanes (two major and two minor vanes). Our brazing procedure consists of two steps. The first step involves the brazing of the four vanes in a horizontal position. The second step consists of brazing the vacuum stainless steel flanges to the copper structure in a vertical position. The paper describes the problems encountered with the alignment and the vacuum tightness. The difficulties related to the stress relaxation of the machined copper pieces during the brazing heat treatment are discussed. In addition, the solutions developed to improve the alignment of the brazed RFQ’s are...

  2. Measurement of partial pressures in vacuum technology and vacuum physics (United States)

    Huber, W. K.


    It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

  3. Flash Vacuum Pyrolysis: Techniques and Reactions. (United States)

    Wentrup, Curt


    Flash vacuum pyrolysis (FVP) had its beginnings in the 1940s and 1950s, mainly through mass spectrometric detection of pyrolytically formed free radicals. In the 1960s many organic chemists started performing FVP experiments with the purpose of isolating new and interesting compounds and understanding pyrolysis processes. Meanwhile, many different types of apparatus and techniques have been developed, and it is the purpose of this review to present the most important methods as well as a survey of typical reactions and observations that can be achieved with the various techniques. This includes preparative FVP, chemical trapping reactions, matrix isolation, and low temperature spectroscopy of reactive intermediates and unstable molecules, the use of online mass, photoelectron, microwave, and millimeterwave spectroscopies, gas-phase laser pyrolysis, pulsed pyrolysis with supersonic jet expansion, very low pressure pyrolysis for kinetic investigations, solution-spray and falling-solid FVP for involatile compounds, and pyrolysis over solid supports and reagents. Moreover, the combination of FVP with matrix isolation and photochemistry is a powerful tool for investigations of reaction mechanism. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Microscale Digital Vacuum Electronic Gates (United States)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)


    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  5. Carbon nanotubes based vacuum gauge (United States)

    Rudyk, N. N.; Il’in, O. I.; Il’ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.


    We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

  6. Vacuum Cleaner Fan Being Improved (United States)

    Tweedt, Daniel L.


    As part of the technology utilization program at the NASA Lewis Research Center, efforts are underway to transfer aerospace technologies to new areas of practical application. One such effort involves using advanced computational fluid dynamics (CFD) codes for turbomachinery to analyze the internal fluid dynamics of low-speed fans and blowers. This year, the Kirby Company in Cleveland, Ohio, approached NASA with a request for technologies that could help them improve their vacuum cleaners. Of particular interest to Kirby is the high-frequency blade-passing noise generation of their vacuum cleaner fan at low airflow rates.

  7. Gases and vacua handbook of vacuum physics

    CERN Document Server

    Beck, A H


    Handbook of Vacuum Physics, Volume 1: Gases and Vacua provides information on the many aspects of vacuum technology, from material on the quantum theoretical aspects of the complex semi-conductors used for thermionic and photo-electric emission to data on the performance of commercially available pumps, gauges, and high-vacuum materials. The handbook satisfies the need of workers using vacuum apparatuses or works on the diverse applications of high-vacuum technology in research and industry. The book is a compilation of long articles prepared by experts in vacuum technology. Sufficient theoret

  8. Cleaner Vacuum-Bag Curing (United States)

    Clemons, J. M.; Penn, B. G.; Ledbetter, Frank E., III; Daniels, J. G.


    Improvement upon recommended procedures saves time and expense. Autoclave molding in vacuum bag cleaner if adhesive-backed covering placed around caul plate as well as on mold plate. Covering easy to remove after curing and leaves caul plate free of resin deposits.

  9. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann


    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  10. Quantum Vacuum Structure and Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Rafelski, Johann; Labun, Lance; Hadad, Yaron; /Arizona U. /Munich U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC


    Contemporary physics faces three great riddles that lie at the intersection of quantum theory, particle physics and cosmology. They are: (1) The expansion of the universe is accelerating - an extra factor of two appears in the size; (2) Zero-point fluctuations do not gravitate - a matter of 120 orders of magnitude; and (3) The 'True' quantum vacuum state does not gravitate. The latter two are explicitly problems related to the interpretation and the physical role and relation of the quantum vacuum with and in general relativity. Their resolution may require a major advance in our formulation and understanding of a common unified approach to quantum physics and gravity. To achieve this goal we must develop an experimental basis and much of the discussion we present is devoted to this task. In the following, we examine the observations and the theory contributing to the current framework comprising these riddles. We consider an interpretation of the first riddle within the context of the universe's quantum vacuum state, and propose an experimental concept to probe the vacuum state of the universe.

  11. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab


    The same vacuum chamber as in 7810256, read the detailed description there. Here, the 4 strip-shaped ion-getter pumps are poised at the entrance to their slots. Ion-getter pumps were not retained, thermal getter pumps were chosen instead (see 8301153 and 8305170).

  12. Filling the vacuum at LHCb

    CERN Multimedia

    Katarina Anthony


    Last month, the Vacuum, Surfaces and Coatings (VSC) group was tasked with an unusually delicate operation in the LHCb experiment cavern: removing the LHC beam pipe while keeping the sensitive Vertex Locator vacuum vessel (VELO) completely isolated from the action.   The VSC group seal off the VELO beam pipe with a flange. Image: Gloria Corti. LHCb’s VELO detector is one of the crown jewels of the experiment. With detector elements surrounded by a vacuum, it gets as close as 5 cm from the beam. Fantastic for physics, but difficult for all-important access. “Because of the sensitivity of the VELO detector and its proximity to the beam, the collaboration decided not to bake (see box) its portion of the beam pipe,” says Giulia Lanza (TE-VSC-LBV), the expert in charge of the beam vacuum operation. “Our group was therefore asked to remove the rest of the LHC beam pipe while keeping the VELO portion of the pipe completely isolated. This work...

  13. Vacuum Stability of Standard Model^{++}

    CERN Document Server

    Anchordoqui, Luis A.; Goldberg, Haim; Huang, Xing; Lust, Dieter; Taylor, Tomasz R.; Vlcek, Brian


    The latest results of the ATLAS and CMS experiments point to a preferred narrow Higgs mass range (m_h \\simeq 124 - 126 GeV) in which the effective potential of the Standard Model (SM) develops a vacuum instability at a scale 10^{9} -10^{11} GeV, with the precise scale depending on the precise value of the top quark mass and the strong coupling constant. Motivated by this experimental situation, we present here a detailed investigation about the stability of the SM^{++} vacuum, which is characterized by a simple extension of the SM obtained by adding to the scalar sector a complex SU(2) singlet that has the quantum numbers of the right-handed neutrino, H", and to the gauge sector an U(1) that is broken by the vacuum expectation value of H". We derive the complete set of renormalization group equations at one loop. We then pursue a numerical study of the system to determine the triviality and vacuum stability bounds, using a scan of 10^4 random set of points to fix the initial conditions. We show that, if there...

  14. Vacuum assisted closure in coloproctology

    NARCIS (Netherlands)

    Bemelman, W.A.


    Vacuum-assisted closure has earned its indications in coloproctology. It has been described with variable results in the treatment of large perineal defects after abdominoperineal excision, in the treatment of stoma dehiscence and perirectal abscesses. The most promising indication for

  15. IR + VUV double resonance spectroscopy and extended density functional theory studies of ketone solvation by alcohol: 2-butanone.(methanol)n, n = 1-4 clusters (United States)

    Shin, Joong-Won; Bernstein, Elliot R.


    Infrared plus vacuum ultraviolet (IR + VUV) photoionization vibrational spectroscopy of 2-butanone/methanol clusters [MEK.(MeOH)n, n = 1-4] is performed to explore structures associated with hydrogen bonding of MeOH molecules to the carbonyl functional group of the ketone. IR spectra and X3LYP/6-31++G(d,p) calculations show that multiple isomers of MEK.(MeOH)n are generated in the molecular beam as a result of several hydrogen bonding sites available to the clusters throughout the size range investigated. Isomer interconversion involving solvating MeOH rearrangement should probably occur for n = 1 and 2. The mode energy for a hydrogen bonded OH stretching transition gradually redshifts as the cluster size increases. Calculations suggest that the n = 3 cluster isomers adopt structures in which the MEK molecule is inserted into the cyclic MeOH hydrogen bond network. In larger structures, the cyclic network may be preserved.


    Energy Technology Data Exchange (ETDEWEB)

    William S. McPhee


    The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and

  17. Vacuum polarization and Hawking radiation (United States)

    Rahmati, Shohreh

    Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.

  18. Spectroscopy and perturbation analysis of the A$^1\\Pi$(v=0) state of $^{13}$C$^{16}$O

    CERN Document Server

    Niu, M L; Trivikram, T Madhu; Heays, A N; de Oliveira, N; Salumbides, E J; Ubachs, and W


    The lowest $v=0$ level of the A$^1\\Pi$, state of the $^{13}$C$^{16}$O isotopologue of carbon monoxide has been reinvestigated with a variety of high resolution spectroscopic techniques. The A$^1\\Pi-$X$^1\\Sigma^+(0,0)$ band has been studied by vacuum-ultraviolet Fourier-transform absorption spectroscopy, using the SOLEIL synchrotron as a radiation source. Spectra were obtained under quasi-static gas conditions at liquid-nitrogen temperature, room temperature and at an elevated temperature of 900 K, with absolute accuracies of 0.01$-$0.03 cm$^{-1}$. Two-photon Doppler-free laser spectroscopy has been applied to a limited number of transitions in the A$^1\\Pi-$X$^1\\Sigma^+(0,0)$ band, under collision-free circumstances of a molecular beam, yielding an absolute accuracy of 0.002 cm$^{-1}$. The third technique is high-resolution Fourier-transform emission spectroscopy in the visible region applied to the B$^1\\Sigma^+-$A$^1\\Pi(0,0)$ band in a gas discharge, at an absolute accuracy of up to 0.003 cm$^{-1}$. With thes...

  19. Ultraviolet-radiation-curable paints

    Energy Technology Data Exchange (ETDEWEB)

    Grosset, A M; Su, W F.A.; Vanderglas, E


    In product finishing lines, ultraviolet radiation curing of paints on prefabricated structures could be more energy efficient than curing by natural gas fired ovens, and could eliminate solvent emission. Diffuse ultraviolet light can cure paints on three dimensional metal parts. In the uv curing process, the spectral output of radiation sources must complement the absorption spectra of pigments and photoactive agents. Photosensitive compounds, such as thioxanthones, can photoinitiate unsaturated resins, such as acrylated polyurethanes, by a free radical mechanism. Newly developed cationic photoinitiators, such as sulfonium or iodonium salts (the so-called onium salts) of complex metal halide anions, can be used in polymerization of epoxy paints by ultraviolet light radiation. One-coat enamels, topcoats, and primers have been developed which can be photoinitiated to produce hard, adherent films. This process has been tested in a laboratory scale unit by spray coating these materials on three-dimensional objects and passing them through a tunnel containing uv lamps.

  20. Gravitational Waves in Decaying Vacuum Cosmologies


    David Alejandro Tamayo Ramirez


    In the present monograph we study in detail the primordial gravitational waves in cosmologies with a decaying vacuum. The decaying vacuum models are an alternative to solve the cosmological constant problem attributing a dynamic to the vacuum energy. The problem of primordial gravitational waves is discussed in the framework of an expanding, flat, spatially homogeneous and isotropic FLRW Universe described by General Relativity theory with decaying vacuum energy density of the type $\\\\Lambda ...

  1. Robot Vacuum Cleaner Personality and Behavior


    Hendriks, A.F.M.; Meerbeek, B.W.; Boess, S.; Pauws, S.C.; Sonneveld, M.


    In this paper we report our study on the user experience of robot vacuum cleaner behavior. How do people want to experience this new type of cleaning appliance? Interviews were conducted to elicit a desired robot vacuum cleaner personality. With this knowledge in mind, behavior was designed for a future robot vacuum cleaner. A video prototype was used to evaluate how people experienced the behavior of this robot vacuum cleaner. The results indicate that people recognizedthe intended personali...

  2. Laser target using continuous supersonic jet in vacuum

    Directory of Open Access Journals (Sweden)

    Ogata Yujin


    Full Text Available For an extreme ultraviolet (EUV light source, Sn plasmas, which can produce a strong radiation with high conversion efficiency at 13.5 nm, attract attention. The purpose of this study is to establish technology to form and recover a tin vapor supersonic jet in vacuum and to make clear the interaction between the supersonic free jet and an incident laser. In order to make the tin vapor, a tantalum crucible is inductively heated up and the radiation loss is compared with the input energy. We observe the shock waves in argon jet emitted from a supersonic nozzle by a Schlieren image. In the future, we will increase the number of shields and heat the tantalum crucible to the boiling point of tin. We are planning to make a study on the interaction process between laser and the free jet.

  3. Laser target using continuous supersonic jet in vacuum (United States)

    Ogata, Yujin; Takahashi, Kazumasa; Kuwabara, Hajime; Nakajima, Mitsuo; Horioka, Kazuhiko


    For an extreme ultraviolet (EUV) light source, Sn plasmas, which can produce a strong radiation with high conversion efficiency at 13.5 nm, attract attention. The purpose of this study is to establish technology to form and recover a tin vapor supersonic jet in vacuum and to make clear the interaction between the supersonic free jet and an incident laser. In order to make the tin vapor, a tantalum crucible is inductively heated up and the radiation loss is compared with the input energy. We observe the shock waves in argon jet emitted from a supersonic nozzle by a Schlieren image. In the future, we will increase the number of shields and heat the tantalum crucible to the boiling point of tin. We are planning to make a study on the interaction process between laser and the free jet.

  4. 14 CFR 29.1433 - Vacuum systems. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe...

  5. Utilize Vacuum Forming to Make Interdisciplinary Connections (United States)

    Love, Tyler S.; Valenza, Frank


    The concept of vacuum forming has been around since the 19th century, despite not being fully utilized in industry until the 1950s. In the past, industrial arts classes have used vacuum-forming projects to concentrate solely on the manufacturing process and the final product. However, vacuum forming is not just an old industrial arts activity; it…

  6. 14 CFR 25.1433 - Vacuum systems. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. ...

  7. The Dirac-Electron Vacuum Wave

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.


    Full Text Available This paper argues that the Dirac equation can be interpreted as an interaction between the electron core and the Planck vacuum state, where the positive and negative solutions represent respectively the dynamics of the electron core and a vacuum wave propagating within the vacuum state. Results show that the nonrelativistic positive solution reduces to the Schrödinger wave equation

  8. Ultrasensitive detection system for fiber optic-based ultraviolet spectroscopy (United States)

    Klein, Karl-Friedrich; Belz, Mathias; Dress, Peter; Schelle, B.; Boyle, William J. O.; Grattan, Kenneth T. V.; Franke, Hilmar


    A fiber optic based deep UV-absorption sensor system is characterized, using fibers for light delivery and a liquid core waveguide (LCW) for analyzing liquids. UN-improved fibers with 500 micrometers core diameter are capable of transmitting light intensities below 230 nm with spectral radiant powers above 500 nW/nm at 214 nm. Their short-term behavior and lifetime in respect to UV-stability have been investigated, using a broadband deuterium lamp. To raise the sensitivity of the total system, the absorption path length has been increased significantly using the lightguiding properties of the LCW consisting of a cylindrical glass tube with a Teflon AF 2400 inner coating of about 50 micrometers thickness. Due to lower refractive index of Teflon in comparison to water, the LCW concept offers significant advantages, especially for long optical pathlengths. However, the basic attenuation of the liquid in dependence on the wavelength as to be taken into account. Results on the use of such a system monitoring concentrations of acetylsalicylic acid, acetone and toluene in water are reported and discussed.

  9. Coordinated Ultraviolet Spectroscopy and Optical Photometry of FK Comae (United States)

    Guinan, Edward F.

    FK Comae (HD 117555) is the prototype of a newly identified class of rapidly rotating, apparently single, cool giants which have strong chromospheric and coronal emission rivalling or surpassing those of the most active RS CVn stars. FK Com is the best studied member of the group. It has spectral type about G2 IIIp, a projected rotational velocity v sin i =120 km/s, and is a low amplitude variable with a 2.4d period. Photometry by Dorren, Guinan and McCook in 1982 shows for the first time that the light curve undergoes rapid changes in amplitude, shape, and phase of light minimum. Such behavior is known for the RS CVn stars, but is generally on longer timescales. Analyses of the 1982 light curves have been carried out and show that the light variations appear to be consistent with subluminous regions ("starspots") on the surface of the rapidly rotating giant. The overall spectroscopic and photometric properties are in general best explained by extreme surface activity induced by rapid rotation. Although rapidly rotating cool giants (v sin i about 20 - 50 km/s) are often members of close binary systems in which tidal effects have produced synchronous rotation, there is no evidence for duplicity in FK Com. This has led Bopp and Stencel to suggest that the FK Com stars are coalesced binaries possibly evolved from W UMa systems. We propose to obtain IUE observations at minimum and maximum of a fully developed photometric wave, when the active regions are facing and directed away from the observer respectively. The light variations will be monitored it Villanova during 1983-1984 to determine the optimum time for scheduling the lUE observations. The previous IUE observations of FK Com were made when no photometry was available or when the light variations were small. We also propose to observe during a flare. The flaring activity will be monitored b), H-alpha photometry. During 1982 at least three long-lived (3-10d) flare events were seen.

  10. Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface


    Maier, Florian; Niedermaier, Inga; Steinrück, Hans-Peter


    This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different w...

  11. High-power extreme ultraviolet source based on gas jets

    Energy Technology Data Exchange (ETDEWEB)

    Kubiak, G.D.; Bernardez, L.J.; Krenz, K.


    The authors report on the development of a high power laser plasma Extreme Ultraviolet (EUV) source for Extreme Ultraviolet Lithography. The source is based on the plasma emission of a recycled jet beam of large Xe clusters and produces no particulate debris. The source will be driven by a pulsed laser delivering 1,500 W of focused average power to the cluster jet target. To develop condensers and to optimize source performance, a low power laboratory cluster jet prototype has been used to study the spectroscopy, angular distributions, and EUV source images of the cluster jet plasma emission. In addition, methods to improve the reflectance lifetimes of nearby plasma facing condenser mirrors have been developed. The resulting source yields EUV conversion efficiencies up to 3.8% and mirror lifetimes of 10{sup 9} plasma pulses.

  12. Ultraviolet Echoes of Quasar Accretion Disks (United States)

    Trump, Jonathan


    We propose a novel ultraviolet monitoring campaign with WFC3/UVIS to measure quasar accretion disk structure. The bulk of supermassive black hole growth occurs in luminous quasar phases of rapid accretion, yet the governing physics remains poorly understood. Continuum reverberation mapping (RM) measures the accretion disk size via the time lag between short- and long-wavelength emission: the proposed UV monitoring forms the foundation for simultaneous optical observations (expected to continue for our quasars through 2019). Currently only 4 Seyfert AGNs have UV/optical RM accretion-disk sizes, all low-luminosity and at z<0.02. We propose to monitor 5 new quasars, spanning an order of magnitude higher accretion rate and out to z 1. The 5 quasar targets are drawn from SDSS-RM, a pioneering multi-object spectroscopic RM campaign, and have been monitored with optical photometry and spectroscopy since 2014. The higher luminosity and accurate RM masses of our sample enable the first measurements of accretion-rate effects on accretion-disk size, with UV monitoring directly probing changes in the inner disk suggested by theory and previous indirect observations. Our proposed HST monitoring campaign is unusually efficient, targeting 5 quasars per orbit using the DASH method with UVIS subarray readouts. We use simulations to demonstrate that our 2-day cadence over 32 epochs will accurately measure continuum lags and accretion-disk structure. Ultraviolet monitoring of these 5 quasars will enable critical new measurements of accretion-disk structure during the rapid accretion mode that dominates black hole growth.

  13. Fabrication of graphene from graphite by a thermal assisted vacuum arc discharge system (United States)

    Cheng, Guo-Wei; Chu, Kevin; Chen, Jeng Shiung; Tsai, Jeff T. H.


    In this study, graphene was fabricated on copper foils using a high temperature furnace embedded in a vacuum arc discharge method. Combining the advantages of chemical vapor deposition and vacuum arc discharge, single-layer graphene can be fabricated at 600 °C base temperature from the mini furnace embedded with a fast heating via the photon radiation from the vacuum arc to 1100 °C on the substrates' surface. The optimal fabrication condition was determined through a series of experiments on ambient pressure, processing time, arc currents, and the cooling process. Observations by scanning electron microscopy, Raman spectroscopy, and optical microscopy showed that the main products were single-layer graphene, which has a uniform thickness across the entire substrate. The results demonstrated that the combination of a vacuum arc with a thermal method that uses graphite as a carbon source provides a low-cost and straight forward method to synthesize graphene films for graphene-based applications.

  14. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab


    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  15. Advanced window incorporating vacuum glazing (United States)

    Asano, Osamu; Misonou, Masao; Kato, Hidemi; Nagasaka, Shigeki


    Vacuum glazing product named SPACIATM, being an unique product with very high levels of thermal insulation properties in a very small thickness, is described in detail. The construction and manufacturing process of SPACIATM are reported. Its design, which was originally established by R.E. Collins et al. of the University of Sydney, has been adjusted in order to meet the requirements of the Japanese market and the requirements of mass production process. SPACIATM is found to have several unique features including airborne sound insulation as well as thermal insulation. Energy required for air conditioning was simulated for Japanese houses with various glazings, and it was revealed that SPACIATM could save the energy efficiently. Finally, hybrid IG unit, where vacuum glazing is incorporated into a conventional IG unit, is proposed for further improvement of thermal insulation.

  16. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab


    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  17. Vacuum Alignment with more Flavors

    DEFF Research Database (Denmark)

    Ryttov, Thomas


    _f=2$ and $N_f=3$ we reproduce earlier known results including the Dashen phase with spontaneous violation of the combined charge conjugation and parity symmetry, CP. For $N_f=4$ we find regions with and without spontaneous CP violation. We then generalize to an arbitrary number of flavors. Here......We study the alignment of the vacuum in gauge theories with $N_f$ Dirac fermions transforming according to a complex representation of the gauge group. The alignment of the vacuum is produced by adding a small mass perturbation to the theory. We study in detail the $N_f=2,3$ and $4$ case. For $N...... it is shown that at the point where $N_f-1$ flavors are degenerate with positive mass $m>0$ and the mass of the $N_f$'th flavor becomes negative and equal to $-m$ CP breaks spontaneously....

  18. Visualizing electromagnetic vacuum by MRI

    CERN Document Server

    Chandrashekar, Chandrika S; Chandrashekar, S; Taylor, Erika A; Taylor, Deanne M


    Based upon Maxwell's equations, it has long been established that oscillating electromagnetic (EM) fields incident upon a metal surface decay exponentially inside the conductor, leading to a virtual EM vacuum at sufficient depths. Magnetic resonance imaging (MRI) utilizes radiofrequency (r.f.) EM fields to produce images. Here we present the first visualization of an EM vacuum inside a bulk metal strip by MRI, amongst several novel findings. We uncover unexpected MRI intensity patterns arising from two orthogonal pairs of faces of a metal strip, and derive formulae for their intensity ratios. Further, we furnish chemical shift imaging (CSI) results that discriminate different faces (surfaces) of a metal block according to their distinct nuclear magnetic resonance (NMR) chemical shifts, which holds much promise for monitoring surface chemical reactions noninvasively. Bulk metals are ubiquitous, and MRI is a premier noninvasive diagnostic tool. Combining the two, the emerging field of bulk metal MRI can be expe...

  19. Quantum vacuum and dark matter

    CERN Document Server

    Hajdukovic, Dragan Slavkov


    Recently, the gravitational polarization of the quantum vacuum was proposed as alternative to the dark matter paradigm. In the present paper we consider four benchmark measurements: the universality of the central surface density of galaxy dark matter haloes, the cored dark matter haloes in dwarf spheroidal galaxies, the non-existence of dark disks in spiral galaxies and distribution of dark matter after collision of clusters of galaxies (the Bullet cluster is a famous example). Only some of these phenomena (but not all of them) can (in principle) be explained by the dark matter and the theories of modified gravity. However, we argue that the framework of the gravitational polarization of the quantum vacuum allows the understanding of the totality of these phenomena.

  20. Vacuum configuration for inflationary superstring

    Energy Technology Data Exchange (ETDEWEB)

    Baadhio, R.A. (Theoretical Physics Group, Physics Division, Lawrence Berkeley Laboratory and Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States))


    The vacuum configuration for the inflationary superstring theory is established. It is argued that the basic physical contents of the inflationary universe are characterized by the Novikov higher signature. Finally it is shown, with respect to the splitting of Paper II, that the index of the Dirac operator defined in our inflated universe, and in the parallel shadow one, is indeed [ital h]-cobordant.

  1. Entanglement in the Bogoliubov vacuum

    DEFF Research Database (Denmark)

    Poulsen, Uffe Vestergaard; Meyer, T.; Lewenstein, M.


    We analyze the entanglement properties of the Bogoliubov vacuum, which is obtained as a second-order approximation to the ground state of an interacting Bose-Einstein condensate. We work in one- and two-dimensional lattices and study the entanglement between two groups of sites as a function...... and to be favoured by strong interactions. Conversely, long-range entanglement is favoured by relatively weak interactions. No examples of bound entanglement are found....

  2. Field Emission in Vacuum Microelectronics

    CERN Document Server

    Fursey, George; Schwoebel, Paul


    Field emission is a phenomenon described by quantum mechanics. Its emission capability is millions times higher than that of any other known types of electron emission. Nowadays this phenomenon is experiencing a new life due to wonderful applications in the atomic resolution microscopy, in electronic holography, and in the vacuum micro- and nanoelectronics in general. The main field emission properties, and some most remarkable experimental facts and applications, are described in this book.

  3. Oscillations of a polarizable vacuum

    Directory of Open Access Journals (Sweden)

    James G. Gilson


    Full Text Available A classical basis for one-dimensional Schrödinger quantum theory is constructed from simple vacuum polarization harmonic oscillators within standard stochastic theory. The model is constructed on a two-dimensional phase configuration surface with phase velocity vectors that have a speed of light zitterbewegung behaviour character. The system supplies a natural Hermitian scalar product describing probability density which is derived from angular momentum considerations. The generality of the model which is extensive is discussed.

  4. The effect of the operation modes of a gas discharge low-pressure amalgam lamp on the intensity of generation of 185 nm UV vacuum radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: [Russian Academy of Sciences, Joint Institute of High Temperatures (Russian Federation); Drozdov, L. A., E-mail:; Kostyuchenko, S. V.; Sokolov, D. V. [ZAO LIT (Russian Federation); Kudryavtsev, N. N.; Sobur, D. A., E-mail: [Moscow Institute for Physics and Technology (Russian Federation)


    The effect of the discharge current, mercury vapor pressure, and the inert gas pressure on the intensity and efficiency of the 185 nm line generation are considered. The spectra of the UV radiation (vacuum ultraviolet) transmission by protective coatings from the oxides of rare earth metals and aluminum are investigated.

  5. Concept for a MEMS-type vacuum sensor based on electrical conductivity measurements

    Directory of Open Access Journals (Sweden)

    F. J. Giebel


    Full Text Available The concept of the micro-structured vacuum sensor presented in this article is the measurement of the electrical conductivity of thinned gases in order to develop a small, economical and quite a simple type of vacuum sensor. There are already some approaches for small vacuum sensors. Most of them are based on conservative measurement principles similar to those used in macroscopic vacuum gauges. Ionization gauges use additional sources of energy, like hot cathodes, ultraviolet radiation or high voltage for example, for ionizing gas molecules and thereby increasing the number of charge carriers for measuring low pressures. In contrast, the concept discussed here cannot be found in macroscopic sensor systems because it depends on the microscopic dimension of a gas volume defined by two electrodes. Here we present the concept and the production of a micro-structured vacuum sensor chip, followed by the electrical characterization. Reference measurements with electrodes at a distance of about 1 mm showed currents in the size of picoampere and a conductivity depending on ambient pressure. In comparison with these preliminary measurements, fundamental differences regarding pressure dependence of the conductivity are monitored in the electrical characterization of the micro-structured sensor chip. Finally the future perspectives of this sensor concept are discussed.

  6. Running Jobs in the Vacuum (United States)

    McNab, A.; Stagni, F.; Ubeda Garcia, M.


    We present a model for the operation of computing nodes at a site using Virtual Machines (VMs), in which VMs are created and contextualized for experiments by the site itself. For the experiment, these VMs appear to be produced spontaneously "in the vacuum" rather having to ask the site to create each one. This model takes advantage of the existing pilot job frameworks adopted by many experiments. In the Vacuum model, the contextualization process starts a job agent within the VM and real jobs are fetched from the central task queue as normal. An implementation of the Vacuum scheme, Vac, is presented in which a VM factory runs on each physical worker node to create and contextualize its set of VMs. With this system, each node's VM factory can decide which experiments' VMs to run, based on site-wide target shares and on a peer-to-peer protocol in which the site's VM factories query each other to discover which VM types they are running. A property of this system is that there is no gate keeper service, head node, or batch system accepting and then directing jobs to particular worker nodes, avoiding several central points of failure. Finally, we describe tests of the Vac system using jobs from the central LHCb task queue, using the same contextualization procedure for VMs developed by LHCb for Clouds.

  7. Vacuum electronics applications at CERN

    CERN Document Server

    Jensen, E


    CERN operates a large number of vacuum electronics based RF power amplifiers covering a wide frequency range – over 300 sockets with 24 different grid tubes and klystrons are in use and require constant care to insure reliable operation of the accelerators. This is in particular true for the LHC and its injector chain, for which a program of improvement and stepwise upgrade has started. These include IOT’s for the SPS and klystrons and modulators for Linac4 and SPL. The CLIC study and the CTF3 facility are relevant to vacuum electronics in many ways: The CLIC primary RF power, to be provided at 1 GHz, requires highest possible efficiency and phase stability, MBK’s are likely candidates. The CLIC RF power source and CTF3 are themselves large vacuum electronics applications, consequently there are areas of common interest and concern, including fabrication techniques, pulse compression techniques, breakdown and multipactor theory and simulation, material fatigue, numerical analysis of slow-wave structures...

  8. Improved Aerogel Vacuum Thermal Insulation (United States)

    Ruemmele, Warren P.; Bue, Grant C.


    An improved design concept for aerogel vacuum thermal-insulation panels calls for multiple layers of aerogel sandwiched between layers of aluminized Mylar (or equivalent) poly(ethylene terephthalate), as depicted in the figure. This concept is applicable to both the rigid (brick) form and the flexible (blanket) form of aerogel vacuum thermal-insulation panels. Heretofore, the fabrication of a typical aerogel vacuum insulating panel has involved encapsulation of a single layer of aerogel in poly(ethylene terephthalate) and pumping of gases out of the aerogel-filled volume. A multilayer panel according to the improved design concept is fabricated in basically the same way: Multiple alternating layers of aerogel and aluminized poly(ethylene terephthalate) are assembled, then encapsulated in an outer layer of poly(ethylene terephthalate), and then the volume containing the multilayer structure is evacuated as in the single-layer case. The multilayer concept makes it possible to reduce effective thermal conductivity of a panel below that of a comparable single-layer panel, without adding weight or incurring other performance penalties. Implementation of the multilayer concept is simple and relatively inexpensive, involving only a few additional fabrication steps to assemble the multiple layers prior to evacuation. For a panel of the blanket type, the multilayer concept, affords the additional advantage of reduced stiffness.

  9. Ultraviolet light and cutaneous lupus

    NARCIS (Netherlands)

    Bijl, Marc; Kallenberg, Cees G. M.


    Exposure to ultraviolet (UV) light is one of the major factors known to trigger cutaneous disease activity in (systemic) lupus erythematosus patients. UV light, UVB in particular, is a potent inducer of apoptosis. Currently, disturbed clearance of apoptotic cells is one of the concepts explaining


    NARCIS (Netherlands)

    Eliel, E.R.; Hogervorst, W.; van Leeuwen, K.A.H.; Post, B.H.


    High resolution laser spectroscopy has been applied to the study of three ultraviolet transitions in Europium at λ = 294.8, 295.1 and 295.8 nm. The tunable narrowband UV has been generated by intracavity frequency doubling in a cw ring dye laser using a temperate tuned, Brewster angled ADA crystal.

  11. On the Increasing Fragility of Human Teeth with Age: ADeep-Ultraviolet Resonance Raman Study

    Energy Technology Data Exchange (ETDEWEB)

    Ager III, J.W.; Nalla, R.K.; Balooch, G.; Kim, G.; Pugach, M.; Habelitz, S.; Marshall, G.W.; Kinney, J.H.; Ritchie, R.O.


    Ultraviolet resonance Raman spectroscopy (UVRRS) using 244nm excitation was used to investigate the impact of aging on humandentin. The intensity of a spectroscopic feature from the peptide bondsin the collagen increases with tissue age, similar to a finding reportedpreviously for human cortical bone.

  12. Electron spectrometer for gas-phase spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bozek, J.D.; Schlachter, A.S. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)


    An electron spectrometer for high-resolution spectroscopy of gaseous samples using synchrotron radiation has been designed and constructed. The spectrometer consists of a gas cell, cylindrical electrostatic lens, spherical-sector electron energy analyzer, position-sensitive detector and associated power supplies, electronics and vacuum pumps. Details of the spectrometer design are presented together with some representative spectra.

  13. Method for the protection of extreme ultraviolet lithography optics (United States)

    Grunow, Philip A.; Clift, Wayne M.; Klebanoff, Leonard E.


    A coating for the protection of optical surfaces exposed to a high energy erosive plasma. A gas that can be decomposed by the high energy plasma, such as the xenon plasma used for extreme ultraviolet lithography (EUVL), is injected into the EUVL machine. The decomposition products coat the optical surfaces with a protective coating maintained at less than about 100 .ANG. thick by periodic injections of the gas. Gases that can be used include hydrocarbon gases, particularly methane, PH.sub.3 and H.sub.2S. The use of PH.sub.3 and H.sub.2S is particularly advantageous since films of the plasma-induced decomposition products S and P cannot grow to greater than 10 .ANG. thick in a vacuum atmosphere such as found in an EUVL machine.

  14. Terahertz spectroscopy

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd


    In this presentation I will review methods for spectroscopy in the THz range, with special emphasis on the practical implementation of the technique known ad THz time-domain spectroscopy (THz-TDS). THz-TDS has revived the old field of far-infrared spectroscopy, and enabled a wealth of new activit...

  15. Laser-induced plasma from pure and doped water-ice at high fluence by ultraviolet and infrared radiation - art. no. 70050X

    DEFF Research Database (Denmark)

    Schou, Jørgen; Matei, A.; Rodrigo, Katarzyna Agnieszka


    Ice made of ultrapure water or water doped with 1 % polymer (polyethylene glycol, "PEG") was irradiated by laser light with fluences between 2 and 80 J/cm(2) in the ultraviolet (UV) regime at 355 nm and in the infrared (IR) regime at 1064 nm in vacuum. In the UV regime there is a threshold...

  16. The Swift-UVOT ultraviolet and visible grism calibration


    Kuin, N. P. M.; Landsman, W.; Breeveld, A. A.; Page, M. J.; James, C.; Lamoureux, H.; Mehdipour, M.; Still, M.; Yershov, V.; Brown, P.J.; Carter, M; Mason, K. O.; Kennedy, T.; Marshall, F.; Roming, P. W. A.


    We present the calibration of the Swift UVOT grisms, of which there are two, providing low-resolution field spectroscopy in the ultraviolet and optical bands respectively. The UV grism covers the range 1700-5000 Angstrom with a spectral resolution of 75 at 2600 Angstrom for source magnitudes of u=10-16 mag, while the visible grism covers the range 2850-6600 Angstrom with a spectral resolution of 100 at 4000 Angstrom for source magnitudes of b=12-17 mag. This calibration extends over all detec...

  17. Vacuum Chambers for LEP sections

    CERN Multimedia


    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  18. Wet/Dry Vacuum Cleaner (United States)

    Reimers, Harold; Andampour, Jay; Kunitser, Craig; Thomas, Ike


    Vacuum cleaner collects and retains dust, wet debris, and liquids. Designed for housekeeping on Space Station Freedom, it functions equally well in normal Earth Gravity or in microgravity. Generates acoustic noise at comfortably low levels and includes circuitry that reduces electromagnetic interference to other electronic equipment. Draws materials into bag made of hydrophobic sheet with layers of hydrophilic super-absorbing pads at downstream end material. Hydrophilic material can gel many times its own weight of liquid. Blower also provides secondary airflow to cool its electronic components.

  19. Ultraviolet extensions of particle physics

    DEFF Research Database (Denmark)

    Berthier, Laure Gaëlle

    The discovery of the Higgs boson in 2012 at the Large Hadron Collider completed the Standard Model field content. Many questions though remain unanswered by the Standard Model triggering a search for new physics. New physics could manifest itself at the Large Hadron Collider by the discovery of new...... particles. However, the lack of new resonances might suggest that these new particles are still out of reach which leaves us with few options. Two possibilities are explored in this thesis. The first is to study precision measurements which might indicate new physics as small deviations from the Standard...... are expressed as power series with missing higher order terms. We also show how to connect ultraviolet models of new physics to the Standard Model effective field theory and calculate bounds on them using the Standard Model effective field theory fit results. Finally, we study a nonrelativistic ultraviolet...

  20. Thin-wall vacuum domain evolution

    Directory of Open Access Journals (Sweden)

    V.A. Berezin


    Full Text Available In the framework of general relativity the equation of motion of a thin-wall vacuum shell is derived at arbitrary values of the vacuum parameters inside and outside the shell. We obtain that the velocity of the walls of the true vacuum bubble at its expansion does not tend to the velocity of light. We find that vacuum shells could exist now in the universe, which do not contradict to observational cosmology. The types of black holes created are investigated. Restrictions on the mass of the black holes formed from remnants of the false vacuum and on the fraction of the vacuum energy pumped into such black holes are obtained.

  1. A new vacuum for Loop Quantum Gravity

    CERN Document Server

    Dittrich, Bianca


    We construct a new vacuum for loop quantum gravity, which is dual to the Ashtekar-Lewandowski vacuum. Because it is based on BF theory, this new vacuum is physical for $(2+1)$-dimensional gravity, and much closer to the spirit of spin foam quantization in general. To construct this new vacuum and the associated representation of quantum observables, we introduce a modified holonomy-flux algebra which is cylindrically consistent with respect to the notion of refinement by time evolution suggested in [1]. This supports the proposal for a construction of a physical vacuum made in [1,2], also for $(3+1)$-dimensional gravity. We expect that the vacuum introduced here will facilitate the extraction of large scale physics and cosmological predictions from loop quantum gravity.

  2. Vacuum systems for the ILC helical undulator

    CERN Document Server

    Malyshev, O B; Clarke, J A; Bailey, I R; Dainton, J B; Malysheva, L I; Barber, D P; Cooke, P; Baynham, E; Bradshaw, T; Brummitt, A; Carr, S; Ivanyushenkov, Y; Rochford, J; Moortgat-Pick, G A


    The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr∼100nTorr in a narrow chamber of 4–6mm4–6mm inner diameter, with a long length of 100–200m100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.

  3. Ultraviolet Protection by Fabric Engineering

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar Singh


    Full Text Available Background. The increasing emission of greenhouse gases has evoked the human being to save the ozone layer and minimize the risk of ultraviolet radiation (UVR. Various fabric structures have been explored to achieve desired ultraviolet protection factor (UPF in various situations. Objective. In this study, the effect of various filament configurations like twisted, flat, intermingled, and textured in multifilament yarns on fabric in different combinations is assessed in order to engineer a fabric of better ultraviolet protection factor (UPF. Methods. In order to engineer a fabric having optimum UV protection with sufficient comfort level in multifilament woven fabrics, four different yarn configurations, intermingled, textured, twisted, and flat, were used to develop twelve different fabric samples. The most UV absorbing and most demanding fibre polyethylene terephthalate (PET was considered in different filament configuration. Results. The combinations of intermingled warp with flat, intermingled, and textured weft provided excellent UVR protection comparatively at about 22.5 mg/cm2 fabric areal density. The presence of twisted yarn reduced the UV protection due to enhanced openness in fabric structure. Conclusion. The appropriate combination of warp and weft threads of different configuration should be selected judiciously in order to extract maximum UV protection and wear comfort attributes in multifilament woven PET fabrics.

  4. Elastomeric Seal Performance after Terrestrial Ultraviolet Radiation Exposure (United States)

    Daniels, Christopher C.; Oravec, Heather A.; Mather, Janice L.; Taylor, Shawn C.; Dunlap, Patrick H.


    Ultraviolet radiation was evaluated to determine its negative effects on the performance of elastomeric gas pressure seals. The leak rates of the silicone elastomer S0383-70 O-ring test articles were used to quantify the degradation of the seals after exposure to vacuum-ultraviolet and/or middle-to-near-ultraviolet wavelength radiation. Three groups of seals were exposed in terrestrial facilities to 115-165 nm wavelength radiation, 230-500 nm wavelength radiation, or both spectrums, for an orbital spaceflight equivalent of 125 hours. The leak rates of the silicone elastomer S0383-70 seals were quantified and compared to samples that received no radiation. Each lot contained six samples and statistical t-tests were used to determine the separate and combined influences of exposure to the two wavelength ranges. A comparison of the mean leak rates of samples exposed to 115-165 nm wavelength radiation to the control specimens showed no difference, suggesting that spectrum was not damaging. The 230-500 nm wavelength appeared to be damaging, as the mean leak rates of the specimens exposed to that range of wavelengths, and those exposed to the combined 115-165 nm and 230-500 nm spectrums, were significantly different from the leak rates of the control specimens. Most importantly, the test articles exposed to both wavelength spectrums exhibited mean leak rates two orders of magnitude larger than any other exposed specimens, which suggested that both wavelength spectrums are important when simulating the orbital environment.

  5. Straw detector: 1 - Vacuum: 0

    CERN Multimedia

    Katarina Anthony


    The NA62 straw tracker is using pioneering CERN technology to measure charged particles from very rare kaon decays. For the first time, a large straw tracker with a 4.4 m2 coverage will be placed directly into an experiment’s vacuum tank, allowing physicists to measure the direction and momentum of charged particles with extreme precision. NA62 measurements using this technique will help physicists take a clear look at the kaon decay rate, which might be influenced by particles and processes that are not included in the Standard Model.   Straw ends are glued to an aluminium frame, a crucial step in the assembly of a module. The ends are then visually inspected before a leak test is performed.  “Although straw detectors have been around since the 1980s, what makes the NA62 straw trackers different is that they can work under vacuum,” explains Hans Danielsson from the PH-DT group leading the NA62 straw project. Straw detectors are basically small drift cha...

  6. Gases vacuum dedusting and cooling

    Directory of Open Access Journals (Sweden)

    Alexey А. Burov


    Full Text Available Represented are the results of operating the ladle degassing vacuum plant (productivity: 120 tons of liquid steel with various dust collectors. The process gases’ cooling and dedusting, obtained in the closed loop buran study, provides opportunity to install a bag filter after that closed loop and its efficient use. Proven is the effectiveness of the cylindrical cyclone replacement with a multichannel (buran dust collector, based on a system of closed-loop (return coupling serially connected curved ducts, where the dusty gas flow rotation axis is vertically positioned. The system of closed-loop serially connected curvilinear channels creates preconditions for the emergence of a negative feedback at the curvilinear gas flow containing transit and circulating flows. These conditions are embodied with circulating flows connecting the in- and outputs of the whole system each channel. The transit flow multiple continuous filtration through the circulating dust layers leads to the formation and accumulation of particles aggregates in the collection chamber. The validity of such a dusty flow control mechanism is confirmed by experimental data obtained in a vacuum chamber. Therefore, replacing one of the two buran’s forevacuum pumps assemblies with the necessary number of curved channels (closed loop is estimated in a promising method.

  7. Vacuum silicon photomultipliers: Recent developments

    Energy Technology Data Exchange (ETDEWEB)

    Barbarino, Giancarlo [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); INFN Napoli (Italy); Barbato, Felicia Carla Tiziana [INFN Napoli (Italy); Campajola, Luigi [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); Asmundis, Riccardo de [INFN Napoli (Italy); De Rosa, Gianfranca [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); Mollo, Carlos Maximiliano [INFN Napoli (Italy); Vivolo, Daniele, E-mail: [Dipartimento Scienze Fisiche, Università “Federico II” Napoli (Italy); INFN Napoli (Italy)


    VSiPMT (Vacuum Silicon PhotoMultiplier Tube) is an innovative design for a modern hybrid, high gain, silicon based photodetector based on the combination of a SiPM with a hemispherical vacuum glass PMT standard envelope. In such a device photoelectrons emitted by the photocathode are accelerated and focused by an electric field towards a small focal area covered by the SiPM which therefore acts as an amplifier, thus substituting the classical dynode chain of a PMT. With a view to the realization of a first prototype of VSiPMT our group is carrying out a preliminary work aimed at the study of SiPM performances as an electron detector, including an accurate Geant4-based simulation of the interaction between SiPM and electron beams. In order to perform a full characterization of the SiPM we developed an experimental setup for the extraction and the acceleration of a beam of backward secondary electrons emitted after the bombardment of a carbon foil by a proton beam extracted in a TTT-3 accelerator.

  8. Vacuum Attachment for XRF Scanner (United States)

    Schramm, Harry F.; Kaiser, Bruce


    Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers - even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles. The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation

  9. Ultrastable and Compact Deep UV Laser Source for Raman Spectroscopy Project (United States)

    National Aeronautics and Space Administration — Deep-ultraviolet (UV) Raman spectroscopy is a powerful method to collect chemically specific information about complex samples because deep-UV (?? < 250 nm)...

  10. Vacuum ultraviolet light production by nuclear irradiation of liquid and gaseous xenon (United States)

    Baldwin, G. C.


    Recent Los Alamos investigations suggest that a liquefied noble element may be the long-sought medium for a nuclear-excited laser or flashlamp. Research is needed to confirm this finding and to provide a basis for design and application studies. Quantitative and qualitative information are needed on the nature and behavior of the excited species, the effects of impurities and additives in the liquid phase under nuclear excitation, and the existence and magnitudes of nonlinear effects. Questions that need to be addressed and the most appropriate types of facilities for this task are identified.

  11. Characterization of Vacuum Ultraviolet (VUV) Radiation for the Development of a Fluorescent Lamp (United States)

    Hasina, Khatun; K. Sharma, A.; K. Barhai, P.


    A negative unipolar pulsed voltage is applied to study internal electrical parameters of the xenon filled dielectric barrier discharge (DBD) sources. The VUV radiation emitted from these sources is characterized by means of the photoluminescence intensity of the red phosphor pellet. The red phosphor converts the VUV radiation into visible radiation and the emission spectra include a peak at 619.56 nm. The emission characteristics of the red phosphor are analyzed in terms of the pressure-distance (pd), rise time and frequency of the pulsed voltage waveform. The emission intensity measured at different operational conditions confirms that the formation and decay of the xenon excimer, Xe2*, increase with the increase in reduced electric field, E/N. After exceeding certain limits of E/N, the intensity of Xe2* decreases rapidly.

  12. Optical properties of InP from infrared to vacuum ultraviolet studied by spectroscopic ellipsometry (United States)

    Subedi, Indra; Slocum, Michael A.; Forbes, David V.; Hubbard, Seth M.; Podraza, Nikolas J.


    The optical properties of an epitaxial indium phosphide (InP) film deposited on an Fe compensated InP (InP:Fe) wafer have been measured at room temperature by ex-situ spectroscopic ellipsometry over a spectral range of 0.038-8.5 eV. The complex dielectric function spectra, ε (E) = ε1 (E) + iε2 (E), have been determined by fitting a parametric model to the experimental ellipsometric data. Kramers-Kronig consistent parameterizations have been applied to describe interband transitions and defect-based sub-bandgap absorption in the 0.73-8.5 eV spectral range, and both phonon modes and free carrier properties in the 0.038-0.73 eV range. Spectra in ε from 0.73-8.5 eV shows ten higher energy interband critical point transitions at 1.36, 1.42, 3.14, 3.34, 4.71, 4.97, 5.88, 6.45, 7.88, and 8.22 eV. The direct band gap energy of 1.37 eV and Urbach energy 46 meV are also determined from spectra in ε. A strong optical phonon mode is identified near 305 cm-1. Electronic transport properties, carrier concentration (N) and mobility (μ), calculated from Drude model with N = 1.9 × 1018 cm-3 and μ = 1559 cm2/Vs agree well with direct electrical Hall effect measurement values of N = 2.2 × 1018 cm-3 and μ = 1590 cm2/Vs. A parameterization of ε from 0.038 to 8.5 eV for the epitaxial InP film is reported.

  13. Advances in vacuum ultraviolet detection with multistep gaseous detectors and application to Cherenkov ring imaging

    CERN Document Server

    Breskin, Amos; Charpak, Georges; Peisert, Anna; Policarpo, Armando; Sauli, Fabio


    The multistep avalanche chamber permits an efficient detection of VUV photons. In a two-step proportional mode charges higher than 1 pC are obtained from single electrons. By using as the final localization step a spark chamber viewed by a TV digitizer it is easy to have imaging of complex patterns. This is applied to Cherenkov ring imaging and (K, pi ) separation with 3 sigma up to 320 GeV is envisaged. The properties of various photoionizable vapours have been studied. By combining a scintillation xenon chamber with a photoionization wire chamber, a resolution of 8.3% (FWHM) has been obtained for 5.9 keV X- rays using tetrakis(dimethylamine)-ethylene vapour. (15 refs).

  14. [Luminescence properties of thenardite activated with Tm3+ under vacuum ultraviolet excitation]. (United States)

    Yusufu, Taximaiti; Abulai, Ajimu; Niyazi, Keyoumu; Su, Zong-Cai; Sidike, Aierken


    The Na2 SO4 : Tm3+ phosphor was synthesized by the high temperature solid state reaction method in air. The crystalline structure was examined by X-ray diffraction (XRD). Narrow bands observed in emission spectra were well identified with the electronic transitions within the 4f12 configurations of Tm3+, and the excitation spectrum is consisted of strong bands assigned to the 4f12 --> 4f11 5d transition at 183 nm, the O(2-)-Tm3+ charge transfer band at 170 nm and weak bands assigned to host absorption (130, 223 and 258 nm). In addition, the authors also found that the content of Tm3+ in the 8-16 mg concentration range caused quenching.

  15. Vacuum ultraviolet Mach-Zehnder interferometer with CaF2 optics (United States)

    Smith, P. L.; Lombardi, G. G.; Cardon, B. L.; Parkinson, W. H.


    CaF2 beam splitters and compensation and test cell windows have been installed in a VUV Mach-Zehnder interferometer. Results of an evaluation of their performance in the VUV, namely, a measurement of the oscillator strength (f value) of the resonance transition at atomic xenon at 146.9610 nm are reported.

  16. Vacuum ultraviolet line radiation measurements of a shock-heated nitrogen plasma (United States)

    Mcclenahan, J. O.


    Line radiation, in the wavelength region from 1040 to 2500 A from nitrogen plasmas, was measured at conditions typical of those produced in the shock layer in front of vehicles entering the earth's atmosphere at superorbital velocities. The radiation was also predicted with a typical radiation transport computer program to determine whether such calculations adequately model plasmas for the conditions tested. The results of the comparison show that the radiant intensities of the lines between 1040 and 1700 A are actually lower than are predicted by such computer models.

  17. A vacuum ultraviolet photoionization study on the thermal decomposition of ammonium perchlorate (United States)

    Góbi, Sándor; Zhao, Long; Xu, Bo; Ablikim, Utuq; Ahmed, Musahid; Kaiser, Ralf I.


    Pyrolysis products of ammonium perchlorate (NH4ClO4) at 483 K were monitored on line and in situ via single photon photoionization reflectron time-of-flight spectrometry (PI-ReTOF-MS) in the photon energy range of 9.00-17.50 eV. The photoionization efficiency curves (PIE) of the subliming product molecules were collected and allowed for detection of three class of products containing chlorine, nitrogen, and oxygen including atoms and free radicals. These results suggest a new insight into possible low-temperature decomposition pathways of NH4ClO4.

  18. Cold vacuum drying facility design requirements

    Energy Technology Data Exchange (ETDEWEB)

    IRWIN, J.J.


    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified.

  19. Vacuum Compatible Percussive Dynamic Cone Penetrometer Project (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a vacuum compatible percussive dynamic cone penetrometer (PDCP), for establishing soil bin characteristics, with the ultimate...

  20. Vacuum Technology Considerations For Mass Metrology (United States)

    Abbott, Patrick J.; Jabour, Zeina J.


    Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

  1. Quantum vacuum noise in physics and cosmology. (United States)

    Davies, P. C. W.


    The concept of the vacuum in quantum field theory is a subtle one. Vacuum states have a rich and complex set of properties that produce distinctive, though usually exceedingly small, physical effects. Quantum vacuum noise is familiar in optical and electronic devices, but in this paper I wish to consider extending the discussion to systems in which gravitation, or large accelerations, are important. This leads to the prediction of vacuum friction: The quantum vacuum can act in a manner reminiscent of a viscous fluid. One result is that rapidly changing gravitational fields can create particles from the vacuum, and in turn the backreaction on the gravitational dynamics operates like a damping force. I consider such effects in early universe cosmology and the theory of quantum black holes, including the possibility that the large-scale structure of the universe might be produced by quantum vacuum noise in an early inflationary phase. I also discuss the curious phenomenon that an observer who accelerates through a quantum vacuum perceives a bath of thermal radiation closely analogous to Hawking radiation from black holes, even though an inertial observer registers no particles. The effects predicted raise very deep and unresolved issues about the nature of quantum particles, the role of the observer, and the relationship between the quantum vacuum and the concepts of information and entropy. (c) 2001 American Institute of Physics.

  2. Vacuum technology in the chemical industry

    CERN Document Server

    Jorisch, Wolfgang


    Based on the very successful German edition and a seminar held by the German Engineers` Association (VDI) on a regular basis for years now, this English edition has been thoroughly updated and revised to reflect the latest developments. It supplies in particular the special aspects of vacuum technology, applied vacuum pump types and vacuum engineering in the chemical, pharmaceutical and process industry application-segments. The text includes chapters dedicated to latest European regulations for operating in hazardous zones with vacuum systems, methods for process pressure control and regulati

  3. Chemical changes exhibited by latent fingerprints after exposure to vacuum conditions. (United States)

    Bright, Nicholas J; Willson, Terry R; Driscoll, Daniel J; Reddy, Subrayal M; Webb, Roger P; Bleay, Stephen; Ward, Neil I; Kirkby, Karen J; Bailey, Melanie J


    The effect of vacuum exposure on latent fingerprint chemistry has been evaluated. Fingerprints were analysed using a quartz crystal microbalance to measure changes in mass, gas chromatography mass spectrometry to measure changes in lipid composition and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine changes in the content of water, fatty acids and their esters after exposure to vacuum. The results are compared with samples aged under ambient conditions. It was found that fingerprints lose around 26% of their mass when exposed to vacuum conditions, equivalent to around 5 weeks ageing under ambient conditions. Further exposure to vacuum causes a significant reduction in the lipid composition of a fingerprint, in particular with the loss of tetradecanoic and pentadecanoic acid, that was not observed in ambient aged samples. There are therefore implications for sequence in which fingerprint development procedures (for example vacuum metal deposition) are carried out, as well as the use of vacuum based methods such as secondary ion mass spectrometry (SIMS) and matrix-assisted laser desorption ionisation (MALDI) in the study of fingerprint chemistry. Copyright © 2013. Published by Elsevier Ireland Ltd.

  4. Semi-automated high-efficiency reflectivity chamber for vacuum UV measurements (United States)

    Wiley, James; Fleming, Brian; Renninger, Nicholas; Egan, Arika


    This paper presents the design and theory of operation for a semi-automated reflectivity chamber for ultraviolet optimized optics. A graphical user interface designed in LabVIEW controls the stages, interfaces with the detector system, takes semi-autonomous measurements, and monitors the system in case of error. Samples and an optical photodiode sit on an optics plate mounted to a rotation stage in the middle of the vacuum chamber. The optics plate rotates the samples and diode between an incident and reflected position to measure the absolute reflectivity of the samples at wavelengths limited by the monochromator operational bandpass of 70 nm to 550 nm. A collimating parabolic mirror on a fine steering tip-tilt motor enables beam steering for detector peak-ups. This chamber is designed to take measurements rapidly and with minimal oversight, increasing lab efficiency for high cadence and high accuracy vacuum UV reflectivity measurements.

  5. Asymptotically safe gravity and nonsingular inflationary big bang with vacuum birth (United States)

    Kofinas, Georgios; Zarikas, Vasilios


    General nonsingular accelerating cosmological solutions for an initial cosmic period of pure vacuum birth era are derived. This vacuum era is described by a varying cosmological "constant" suggested by the renormalization group flow of asymptotic safety scenario near the ultraviolet fixed point. In this scenario, a natural exit from inflation to the standard decelerating cosmology occurs when the energy scale lowers and the cosmological constant becomes insignificant. In the following period where matter is also present, cosmological solutions with characteristics similar to the vacuum case are generated. Remarkably the set of equations allows for particle production and entropy generation. Alternatively, in the case of nonzero bulk viscosity, entropy production and reheating is found. As for the equations of motion, they modify Einstein equations by adding covariant kinetic terms of the cosmological constant which respect the Bianchi identities. An advance of the proposed framework is that it ensures a consistent description of both a quantum vacuum birth of the universe and a subsequent cosmic era in the presence of matter.

  6. In vacuum undulator task force report

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, J.B.; Kao, C.C.; Stefan, P. [and others


    Historically the NSLS has been active in R&D for state-of-the-art electron beams, photon beams and x-ray optics. One of the available straight sections has therefore been dedicated to insertion device R&D. Over the past five to seven years a program aimed at exploiting the very small vertical {beta} function in the straight sections has yielded first a prototype small gap undulator (PSGU) and then an in-vacuum undulator (IVUN). The IVUN sources attain a brightness similar to the existing hybrid wigglers in X21 and X25. They radiate significantly lower total power than the wigglers but produce higher power densities. They provide undulator rather than wiggler spectra. Because of the small gaps and small periods there is not much tunability in these devices and they will have to be purpose-built for a specific scientific program. The original IVUN parameters were chosen for in-elastic x-ray scattering, similar to the scientific program on X21. This put the fundamental at 4.6 keV and the third harmonic at 13.8 keV. The question that this new possible insertion device poses is what science programs can best take advantage of this new insertion device source? To answer this, a task force was formed by M. Hart, NSLS Department Chair and charged with identifying viable scientific programs that could seek outside funding to construct IVUN beamlines. The task force concentrated on experimental programs that are presently being pursued on new insertion devices worldwide. For example, x-ray photon correlation spectroscopy, which takes advantage of the large coherent flux from undulator sources, was considered. However, this program was not considered as the highest priority. The general area of protein crystallography, however, is ideal for the IVUN source. The unique electron beam optics that makes the IVUN possible in the first place also makes the IVUN ideal as a source for microdiffraction.

  7. Determination of Kicker Vacuum Requirements

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    This note examines the effect of elevated vacuum pressures in the kicker region of the DARHT 2nd Axis which can lead to changes in the beam tune due to the long pulse length. The kicker uses Rexolite as an insulator supporting the electrodes. Rexolite is hygroscopic resulting is a large outgassing rate and prolonged pump down times after exposure to atmospheric conditions. LAMDA [1] is used to simulate the effect of ionization of the residual gas resulting in partial space charge neutralization and changes to the tune between the beginning and end of the pulse. The effect of the ion-hose instability is also examined. The purpose of this note is to establish/validate the required pressure in the downstream transport.

  8. TRIUMF cyclotron vacuum system refurbishing (United States)

    Sekachev, I.


    The cyclotron at TRIUMF was commissioned to full energy in 1974. The volume of the cyclotron vacuum tank is about 100 m3 and it operates at 5×10-8 Torr pressure during beam production. The pumping is mainly based on a Phillips B-20 cryogenerator (Stirling cycle 4-cylinder engine). The cryogenerator supplies helium gas at 16 K and 70 K to cryopanels in the tank. The decreasing reliability of the B-20 and demanding maintenance requirements triggered the decision to completely overhaul or replace the cryogenerator. Replacement with the LINDE-1630 helium refrigerator was found to be the most attractive (technically and economically) option. The details of the proposal with installation of the helium refrigerator and with a continuous flow liquid nitrogen shield cooling system are presented.

  9. Progress of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Bayon, A. [F4E, c/ Josep Pla, No. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC “Sintez”, Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382025 (India); Preble, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others


    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure.

  10. Confinement of light in a polarizable vacuum

    Directory of Open Access Journals (Sweden)

    Avinash Khare


    Full Text Available We show that an electrically polarizable vacuum with space-dependent permeability ε(r = μ−1(rexp(−αr2 can confine light whose quanta acquire a mass through interaction with this vacuum.

  11. Robot Vacuum Cleaner Personality and Behavior

    NARCIS (Netherlands)

    Hendriks, A.F.M.; Meerbeek, B.W.; Boess, S.; Pauws, S.C; Sonneveld, M.


    In this paper we report our study on the user experience of robot vacuum cleaner behavior. How do people want to experience this new type of cleaning appliance? Interviews were conducted to elicit a desired robot vacuum cleaner personality. With this knowledge in mind, behavior was designed for a

  12. Vacuum alignment with and without elementary scalars

    DEFF Research Database (Denmark)

    Alanne, Tommi; Gertov, Helene; Meroni, Aurora


    We systematically elucidate differences and similarities of the vacuum alignment issue in composite and renormalizable elementary extensions of the Standard Model featuring a pseudo-Goldstone Higgs. We also provide general conditions for the stability of the vacuum in the elementary framework...

  13. Vacuum sewerage system: an appropriate and economical ...

    African Journals Online (AJOL)

    However, vacuum technology has grown enormously in the last years. This paper reviews the applicability of the vacuum system as opposed to gravity systems, especially in Botswana. It is based on the training and visits to installed systems at Shoshong (Botswana), Dubai (UAE) and Hanau (Germany) offered by Roediger ...

  14. AA, vacuum tank for stochastic precooling

    CERN Document Server

    CERN PhotoLab


    The vaccum tank in which the fast stochastic precooling kicker was installed. It is clad with heating jackets for bake-out to 200 deg C, indispensable for reaching the operational vacuum of 7E-11 Torr. Alain Poncet, responsible for AA vacuum, is looking on. See also 7910268, 8002234.

  15. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner


    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  16. Ultraviolet laser technology and applications

    CERN Document Server

    Elliott, David L


    Ultraviolet Laser Technology and Applications is a hands-on reference text that identifies the main areas of UV laser technology; describes how each is applied; offers clearly illustrated examples of UV opticalsystems applications; and includes technical data on optics, lasers, materials, and systems. This book is unique for its comprehensive, in-depth coverage. Each chapter deals with a different aspect of the subject, beginning with UV light itself; moving through the optics, sources, and systems; and concluding with detailed descriptions of applications in various fields.The text enables pr

  17. Ultraviolet divergences and supersymmetric theories

    Energy Technology Data Exchange (ETDEWEB)

    Sagnotti, A.


    This article is closely related to the one by Ferrara in these same Proceedings. It deals with what is perhaps the most fascinating property of supersymmetric theories, their improved ultraviolet behavior. My aim here is to present a survey of the state of the art as of August, 1984, and a somewhat more detailed discussion of the breakdown of the superspace power-counting beyond N = 2 superfields. A method is also described for simplifying divergence calculations that uses the locality of subtracted Feynman integrals. 74 references.

  18. Ultraviolet luminescence from latent fingerprints. (United States)

    Bramble, S K; Creer, K E; Qiang, W G; Sheard, B


    Illumination of latent fingerprints on white paper using 266-nm radiation from a Nd:YAG laser and photographic detection of their ultraviolet fluorescence, produces images with good ridge detail. The detection rate was 69% in a survey of fingerprints from 34 people compared with only 23% using an argon-ion laser at 514 nm. Prolonged exposure to UV light decreased the inherent UV fluorescence intensity but no adverse effects were observed on subsequent treatment with 1,8-diazafluoren-9-one or ninhydrin.

  19. Raman Spectroscopy. (United States)

    Gerrard, Donald L.


    Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

  20. Anaerobic polymers as high vacuum leak sealants (United States)

    Kendall, B. R. F.


    Anaerobic polymers are useful as solventless leak sealants with good vacuum properties at moderate temperatures. Loctite 290 can seal leaks in a range generally encountered in carefully constructed ultrahigh vacuum and high vacuum systems. It was found that small leaks are sealed best under vacuum, whereas large leaks should be sealed at atmospheric pressure. The high-temperature behavior of Loctite 290 is limited by its fast cure, which prevents deep penetration into small leaks; cracking eventually occurs at the entrance to the leak. Repeated thermal cycling to about 300 C is possible, however, provided viscosity, curing time, and leak size are properly matched to ensure penetration into the body of the leak. This may require special formulations for high temperature vacuum applications.