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Sample records for stable xenon gas

  1. Environmental Applications of Stable Xenon and Radioxenon Monitoring

    SciTech Connect

    Dresel, P. Evan; Olsen, Khris B.; Hayes, James C.; McIntyre, Justin I.; Waichler, Scott R.; Kennedy, B. M.

    2008-06-01

    Improved detection capabilities are needed at several Department of Energy sites to make remedial decisions about facilities and landfill cleanup. For facility monitoring air samples can be collected from within a facility and analyzed for short lived radioxenons to estimate inventories of residual plutonium holdup within the facility. For landfill cleanup activities soil gas sampling for xenon isotopes can be used to define the locations of spent fuel and transuranic wastes. Short-lived radioxenon isotopes are continuously produced by spontaneous fission of plutonium-240 in transuranic wastes. Large volume soil-gas samples provide extremely sensitive measurement of radioxenon in the subsurface; a characteristic of transuranic waste. The analysis employs a modified Automated Radioxenon Sampling and Analysis (ARSA) system. Proof of principle measurements at a Hanford Site liquid waste disposal site showed xenon-133 at levels in soil gas are approximately 16,000 times the detection limit and lower levels of xenon-135 from the spontaneous fission of plutonium-240 were also measured. Stable xenon isotopes are also produced by spontaneous fission but are subject to background concentrations in ambient air samples (facilities) but less so in soil gas where free exchange with ambient air is restricted. Rare gas mass spectrometry is used for highly precise stable xenon isotopic measurements. Stable xenon isotopic ratios from fission are distinct from natural xenon background ratios. Neutron capture on xenon-135 produces an excess of xenon-136 above fission ratios and thus provides a means of distinguishing reactor sources (e.g. spent fuel) from separated transuranic materials (plutonium).

  2. Trapping of xenon gas in closed inner spaces of carbon nanomaterials for stable gas storage under high-vacuum condition

    NASA Astrophysics Data System (ADS)

    Kobayashi, Keita; Yasuda, Hidehiro

    2017-01-01

    Xe gas can be trapped in the closed inner spaces of glassy carbon derived from C60 fullerene by thermal coalescence of C60 in Xe atmosphere and in cap-opened carbon nanotubes (CNTs) covered with an ionic liquid by soaking Xe-adsorbing CNTs in an ionic liquid. The trapped Xe gas is detected by energy dispersive X-ray spectrometry using a spectrometer mounted on an analytical transmission electron microscope. The closed inner spaces store gas molecules even under high-vacuum condition (˜10-5 Pa).

  3. Environmental application of stable xenon and radioxenonmonitoring

    SciTech Connect

    Dresel, P. Evan; Olsen, Khris B.; Hayes, James C.; McIntyre,Justin I.; Waichler, Scott R.; Milbrath, Brian D.; Cooper, Matt; Kennedy,B. Mack

    2006-09-05

    Characterization of transuranic waste is needed to makedecisions about waste site remediation. Soil-gas sampling for xenonisotopes can be used to define the locations of spent fuel andtransuranic wastes. Radioxenon in the subsurface is characteristic oftransuranic waste and can be measured with extreme sensitivity usinglarge-volume soilgas samples. Measurements at the Hanford Site showed133Xe and 135Xe levels indicative of 240Pu spontaneous fission. Stablexenon isotopic ratios from fission are distinct from atmospheric xenonbackground. Neutron capture by 135Xe produces an excess of 136Xe inreactor-produced xenon providing a means of distinguishing spent fuelfrom separated transuranic materials.

  4. Stable xenon nitride at high pressures

    NASA Astrophysics Data System (ADS)

    Peng, Feng; Wang, Yanchao; Wang, Hui; Zhang, Yunwei; Ma, Yanming

    2015-09-01

    Nitrides in many ways are fascinating since they often appear as superconductors, high-energy density, and hard materials. Though there exist a large variety of nitrides, noble gas nitrides are missing in nature. Pursuit of noble gas nitrides has therefore become the subject of topical interests, but remains as a great challenge since molecular nitrogen (N2, a major form of nitrogen) and noble gases are both inert systems and do not interact at normal conditions. We show through a first-principles swarm-structure search that high pressure enables a direct interaction of N2 and xenon (Xe) above 146 GPa. The resultant Xe nitride has a peculiar stoichiometry of XeN6, possessing a high-energy density of approximately 2.4 kJg -1, rivaling that of the modern explosives. Structurally, XeN6 is intriguing with the appearance of chaired N6 hexagons and unusually high 12-coordination of Xe bonded with N. Our work opens up the possibility of achieving Xe nitride with superior high-energy density whose formation is long sought as impossible.

  5. A xenon gas purity monitor for EXO

    NASA Astrophysics Data System (ADS)

    Dobi, A.; Hall, C.; Herrin, S.; Odian, A.; Prescott, C. Y.; Rowson, P. C.; Ackerman, N.; Aharmin, B.; Auger, M.; Barbeau, P. S.; Barry, K.; Benitez-Medina, C.; Breidenbach, M.; Cook, S.; Counts, I.; Daniels, T.; DeVoe, R.; Dolinski, M. J.; Donato, K.; Fairbank, W.; Farine, J.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Green, M.; Hagemann, C.; Hall, K.; Hallman, D.; Hargrove, C.; Karelin, A.; Kaufman, L. J.; Kuchenkov, A.; Kumar, K.; Lacey, J.; Leonard, D. S.; LePort, F.; Mackay, D.; MacLellan, R.; Mong, B.; Montero Díez, M.; Müller, A. R.; Neilson, R.; Niner, E.; O'Sullivan, K.; Piepke, A.; Pocar, A.; Pushkin, K.; Rollin, E.; Sinclair, D.; Slutsky, S.; Stekhanov, V.; Twelker, K.; Voskanian, N.; Vuilleumier, J.-L.; Wichoski, U.; Wodin, J.; Yang, L.; Yen, Y.-R.

    2011-12-01

    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

  6. The use of inert gas xenon for cryopreservation of leukocytes.

    PubMed

    Laptev, D S; Polezhaeva, T V; Zaitseva, O O; Khudyakov, A N; Solomina, O N; Utemov, S V

    2014-06-01

    We studied the possibility of cryopreservation of human blood nuclear cells under protection with inert gas xenon. A method for inducing clathrate anabiosis of leukocytes was developed that preserved the cells for practical use in biology and medicine.

  7. Hyperpolarized xenon NMR and MRI signal amplification by gas extraction

    PubMed Central

    Zhou, Xin; Graziani, Dominic; Pines, Alexander

    2009-01-01

    A method is reported for enhancing the sensitivity of NMR of dissolved xenon by detecting the signal after extraction to the gas phase. We demonstrate hyperpolarized xenon signal amplification by gas extraction (Hyper-SAGE) in both NMR spectra and magnetic resonance images with time-of-flight information. Hyper-SAGE takes advantage of a change in physical phase to increase the density of polarized gas in the detection coil. At equilibrium, the concentration of gas-phase xenon is ≈10 times higher than that of the dissolved-phase gas. After extraction the xenon density can be further increased by several orders of magnitude by compression and/or liquefaction. Additionally, being a remote detection technique, the Hyper-SAGE effect is further enhanced in situations where the sample of interest would occupy only a small proportion of the traditional NMR receiver. Coupled with targeted xenon biosensors, Hyper-SAGE offers another path to highly sensitive molecular imaging of specific cell markers by detection of exhaled xenon gas. PMID:19805177

  8. Radon depletion in xenon boil-off gas

    NASA Astrophysics Data System (ADS)

    Bruenner, S.; Cichon, D.; Lindemann, S.; Undagoitia, T. Marrodán; Simgen, H.

    2017-03-01

    An important background in detectors using liquid xenon for rare event searches arises from the decays of radon and its daughters. We report for the first time a reduction of ^{222}Rn in the gas phase above a liquid xenon reservoir. We show a reduction factor of ≳ 4 for the ^{222}Rn concentration in boil-off xenon gas compared to the radon enriched liquid phase. A semiconductor-based α -detector and miniaturized proportional counters are used to detect the radon. As the radon depletion in the boil-off gas is understood as a single-stage distillation process, this result establishes the suitability of cryogenic distillation to separate radon from xenon down to the 10^{-15} mol/mol level.

  9. Scintillation luminescence for high-pressure xenon gas

    NASA Astrophysics Data System (ADS)

    Kobayashi, S.; Hasebe, N.; Igarashi, T.; Kobayashi, M.-N.; Miyachi, T.; Miyajima, M.; Okada, H.; Okudaira, O.; Tezuka, C.; Yokoyama, E.; Doke, T.; Shibamura, E.; Dmitrenko, V. V.; Ulin, S. E.; Vlasik, K. F.

    2004-09-01

    Scintillation and ionization yields in xenon gas for 5.49MeV alpha-particles were measured in the range of pressure from 0.35 to 3.7MPa and the electric field strength (E) over the number density of xenon atoms (N), E/N from 0 to 5×10-18Vcm2. When our data are normalized at the data point measured by Saito et al., the number of scintillation photons is 2.3×105 while the number of ionization electrons is 2.0×105 at 2.6MPa and at 3.7×10-18Vcm2. The scintillation and ionization yields of xenon doped with 0.2% hydrogen, High-Pressure Xenon gas[H2-0.2%], at 2.6MPa was also measured. Scintillation yield of the Xe-H2 mixture gas is 80% as high as that of pure xenon. It is found that the scintillation yield is luminous enough to generate a trigger pulse of the high-pressure xenon time projection chamber, which is expected as a promising MeV Compton gamma-ray camera.

  10. Continuous flow production of concentrated hyperpolarized xenon gas from a dilute xenon gas mixture by buffer gas condensation.

    PubMed

    Imai, Hirohiko; Yoshimura, Hironobu; Kimura, Atsuomi; Fujiwara, Hideaki

    2017-08-04

    We present a new method for the continuous flow production of concentrated hyperpolarized xenon-129 (HP (129)Xe) gas from a dilute xenon (Xe) gas mixture with high nuclear spin polarization. A low vapor pressure (i.e., high boiling-point) gas was introduced as an alternative to molecular nitrogen (N2), which is the conventional quenching gas for generating HP (129)Xe via Rb-Xe spin-exchange optical-pumping (SEOP). In contrast to the generally used method of extraction by freezing Xe after the SEOP process, the quenching gas separated as a liquid at moderately low temperature so that Xe was maintained in its gaseous state, allowing the continuous delivery of highly polarized concentrated Xe gas. We selected isobutene as the candidate quenching gas and our method was demonstrated experimentally while comparing its performance with N2. Isobutene could be liquefied and removed from the Xe gas mixture using a cold trap, and the concentrated HP (129)Xe gas exhibited a significantly enhanced nuclear magnetic resonance (NMR) signal. Although the system requires further optimization depending on the intended purpose, our approach presented here could provide a simple means for performing NMR or magnetic resonance imaging (MRI) measurements continuously using HP (129)Xe with improved sensitivity.

  11. Diffusion NMR methods applied to xenon gas for materials study

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Rosen, M. S.; Wang, R.; Cory, D. G.; Walsworth, R. L.

    2002-01-01

    We report initial NMR studies of (i) xenon gas diffusion in model heterogeneous porous media and (ii) continuous flow laser-polarized xenon gas. Both areas utilize the pulsed gradient spin-echo (PGSE) techniques in the gas phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients--a brief overview of this area is provided in the Introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t) (an indicator of mean squared displacement), to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. We find that D(t) of imbibed xenon gas at short diffusion times is similar for the mixed bead pack and a pack of the smaller sized beads alone, hence reflecting the pore surface area to volume ratio of the smaller bead sample. The approach of D(t) to the long-time limit follows that of a pack of the larger sized beads alone, although the limiting D(t) for the mixed bead pack is lower, reflecting the lower porosity of the sample compared to that of a pack of mono-sized glass beads. The Pade approximation is used to interpolate D(t) data between the short- and long-time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20-200 mm s-1). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm s-1 owing to the high diffusivity of gases compared with liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data, namely flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack. c2002 John Wiley & Sons, Ltd.

  12. Diffusion NMR methods applied to xenon gas for materials study

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Rosen, M. S.; Wang, R.; Cory, D. G.; Walsworth, R. L.

    2002-01-01

    We report initial NMR studies of (i) xenon gas diffusion in model heterogeneous porous media and (ii) continuous flow laser-polarized xenon gas. Both areas utilize the pulsed gradient spin-echo (PGSE) techniques in the gas phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients--a brief overview of this area is provided in the Introduction. The heterogeneous or multiple-length scale model porous media consisted of random packs of mixed glass beads of two different sizes. We focus on observing the approach of the time-dependent gas diffusion coefficient, D(t) (an indicator of mean squared displacement), to the long-time asymptote, with the aim of understanding the long-length scale structural information that may be derived from a heterogeneous porous system. We find that D(t) of imbibed xenon gas at short diffusion times is similar for the mixed bead pack and a pack of the smaller sized beads alone, hence reflecting the pore surface area to volume ratio of the smaller bead sample. The approach of D(t) to the long-time limit follows that of a pack of the larger sized beads alone, although the limiting D(t) for the mixed bead pack is lower, reflecting the lower porosity of the sample compared to that of a pack of mono-sized glass beads. The Pade approximation is used to interpolate D(t) data between the short- and long-time limits. Initial studies of continuous flow laser-polarized xenon gas demonstrate velocity-sensitive imaging of much higher flows than can generally be obtained with liquids (20-200 mm s-1). Gas velocity imaging is, however, found to be limited to a resolution of about 1 mm s-1 owing to the high diffusivity of gases compared with liquids. We also present the first gas-phase NMR scattering, or diffusive-diffraction, data, namely flow-enhanced structural features in the echo attenuation data from laser-polarized xenon flowing through a 2 mm glass bead pack. c2002 John Wiley & Sons, Ltd.

  13. Xenon-nitrogen chemistry: gas-phase generation and theoretical investigation of the xenon-difluoronitrenium ion F2N-Xe+.

    PubMed

    Operti, Lorenza; Rabezzana, Roberto; Turco, Francesca; Borocci, Stefano; Giordani, Maria; Grandinetti, Felice

    2011-09-12

    The xenon-difluoronitrenium ion F(2)N-Xe(+) , a novel xenon-nitrogen species, was obtained in the gas phase by the nucleophilic displacement of HF from protonated NF(3) by Xe. According to Møller-Plesset (MP2) and CCSD(T) theoretical calculations, the enthalpy and Gibbs energy changes (ΔH and ΔG) of this process are predicted to be -3 kcal mol(-1) . The conceivable alternative formation of the inserted isomers FN-XeF(+) is instead endothermic by approximately 40-60 kcal mol(-1) and is not attainable under the employed ion-trap mass spectrometric conditions. F(2)N-Xe(+) is theoretically characterized as a weak electrostatic complex between NF(2)(+) and Xe, with a Xe-N bond length of 2.4-2.5 Å, and a dissociation enthalpy and free energy into its constituting fragments of 15 and 8 kcal mol(-1), respectively. F(2)N-Xe(+) is more fragile than the xenon-nitrenium ions (FO(2)S)(2)NXe(+), F(5)SN(H)Xe(+), and F(5)TeN(H)Xe(+) observed in the condensed phase, but it is still stable enough to be observed in the gas phase. Other otherwise elusive xenon-nitrogen species could be obtained under these experimental conditions.

  14. Radiation properties of low-pressure discharges in rare-gas mixtures containing xenon

    NASA Astrophysics Data System (ADS)

    Gortchakov, S.; Uhrlandt, D.

    2005-02-01

    Glow discharges in mixtures of xenon with other rare gases can be used as alternatives to mercury-containing UV/VUV radiation sources and fluorescent lamps. The advantages of such sources are environmental compatibility, instant light output after switching on, and less pronounced temperature dependence. However, the optimum choice of the gas composition with respect to the maximum efficiency and power of the xenon resonance radiation as well as to a stable discharge operation still remains an open question. The dc cylindrical positive column of low-pressure discharges in rare-gas mixtures is studied by a detailed self-consistent kinetic description. The influence of the buffer gases helium, neon and argon as well as the appropriate choice of the xenon admixture are revealed by analysing different triple-gas mixtures. Changes in the global power budget and the radial structure of the plasma are discussed. A mixture of He and about 1-2% Xe arises as an optimum composition.

  15. Is xenon eldest?

    NASA Technical Reports Server (NTRS)

    Zahnle, K.

    1994-01-01

    It is well known that the solubility of noble gases in magmas decreases with increasing atomic weight. Xenon, the weightiest of the stable noble gases, is the least soluble atmospheric gas in magma. It is not unreasonable to suppose that the noble gases should have degassed from (or equilibrated with) a bubbling mantle in order of increasing solubility, such that xenon was the most rapidly degassed and helium the least. The apparent relative ages of the famous radiogenic noble gas isotopes agrees, at least qualitatively, with this premise. When atmospheric loss processes are assigned their proper place, several long-standing xenonological puzzles become added evidence for xenon's relative antiquity. Xenon being the afore-mentioned sense the oldest atmospheric gas, will have been most greatly subject to escape, be it impact-driven or EUV-driven. Nonradiogenic xenon's pronounced isotopic fractionation has already been attributed to escape; why it should be more fractionated than krypton would be assigned to xenon's greater atmospheric age. The small atmospheric inventory of xenon relative to the other nonradiogenic noblegases, known as the 'missing xenon' problem, could easily be explained by differential escape. The relatively tiny atmospheric inventories of the radiogenic daughter products of 129 Iodine and 244 Plutonium, both much smaller than would be expected from the inferred abundances of the parents in meteorites, offer a third and fourth data to support the hypothesis that Earth has lost most of its xenon.

  16. Is xenon eldest?

    NASA Technical Reports Server (NTRS)

    Zahnle, K.

    1994-01-01

    It is well known that the solubility of noble gases in magmas decreases with increasing atomic weight. Xenon, the weightiest of the stable noble gases, is the least soluble atmospheric gas in magma. It is not unreasonable to suppose that the noble gases should have degassed from (or equilibrated with) a bubbling mantle in order of increasing solubility, such that xenon was the most rapidly degassed and helium the least. The apparent relative ages of the famous radiogenic noble gas isotopes agrees, at least qualitatively, with this premise. When atmospheric loss processes are assigned their proper place, several long-standing xenonological puzzles become added evidence for xenon's relative antiquity. Xenon being the afore-mentioned sense the oldest atmospheric gas, will have been most greatly subject to escape, be it impact-driven or EUV-driven. Nonradiogenic xenon's pronounced isotopic fractionation has already been attributed to escape; why it should be more fractionated than krypton would be assigned to xenon's greater atmospheric age. The small atmospheric inventory of xenon relative to the other nonradiogenic noblegases, known as the 'missing xenon' problem, could easily be explained by differential escape. The relatively tiny atmospheric inventories of the radiogenic daughter products of 129 Iodine and 244 Plutonium, both much smaller than would be expected from the inferred abundances of the parents in meteorites, offer a third and fourth data to support the hypothesis that Earth has lost most of its xenon.

  17. Structural Plasticity of the Phage P22 Tail Needle gp26 Probed with Xenon Gas

    SciTech Connect

    Olia, A.; Casjens, S; Cingolani, G

    2009-01-01

    The tail needle, gp26, is a highly stable homo-trimeric fiber found in the tail apparatus of bacteriophage P22. In the mature virion, gp26 is responsible for plugging the DNA exit channel, and likely plays an important role in penetrating the host cell envelope. In this article, we have determined the 1.98 A resolution crystal structure of gp26 bound to xenon gas. The structure led us to identify a calcium and a chloride ion intimately bound at the interior of alpha-helical core, as well as seven small cavities occupied by xenon atoms. The two ions engage in buried polar interactions with gp26 side chains that provide specificity and register to gp26 helical core, thus enhancing its stability. Conversely, the distribution of xenon accessible cavities correlates well with the flexibility of the fiber observed in solution and in the crystal structure. We suggest that small internal cavities in gp26 between the helical core and the C-terminal tip allow for flexible swinging of the latter, without affecting the overall stability of the protein. The C-terminal tip may be important in scanning the bacterial surface in search of a cell-envelope penetration site, or for recognition of a yet unidentified receptor on the surface of the host.

  18. Mobility and fluorescence of barium ions in xenon gas for the exo experiment

    NASA Astrophysics Data System (ADS)

    Benitez Medina, Julio Cesar

    The Enriched Xenon Observatory (EXO) is an experiment which aims to observe the neutrinoless double beta decay of 136Xe. The measurement of this decay would give information about the absolute neutrino mass and whether or not the neutrino is its own antiparticle. Since this is a very rare decay, the ability to reject background events by detecting the barium ion daughter from the double beta decay would be a major advantage. EXO is currently operating a detector with 200 kg of enriched liquid xenon, and there are plans to build a ton scale xenon detector. Measurements of the purity of liquid xenon in our liquid xenon test cell are reported. These results are relevant to the research on detection of single barium ions by our research group at Colorado State University. Details of the operation of the purity monitor are described. The effects of using a purifier, recirculation and laser ablation on the purity of liquid xenon are discussed. Mobility measurements of barium in xenon gas are reported for the first time. The variation of mobility with xenon gas pressure suggests that a significant fraction of molecular ions are formed when barium ions interact with xenon gas at high pressures. The measured mobility of Ba+ in Xe gas at different pressures is compared with the predicted theoretical value, and deviations are explained by a model that describes the fraction of molecular ions in Xe gas as a function of pressure. The results are useful for the analysis of experiments of fluorescence of Ba+ in xenon gas. It is also important to know the mobility of the ions in order to calculate the time they interact with an excitation laser in fluorescence experiments and in proposed 136 Ba+ daughter detection schemes. This thesis presents results of detection of laser induced fluorescence of Ba+ ions in Xe gas. Measurements of the pressure broadening of the excitation spectra of Ba+ in xenon gas are presented. Nonradiative decays due to gas collisions and optical pumping

  19. The search for an E(5) critical-point nucleus among the stable xenon isotopes

    NASA Astrophysics Data System (ADS)

    Peters, E. E.; Ross, T. J.; Chakraborty, A.; Crider, B. P.; Kumar, A.; Prados-Estévez, F. M.; Ashley, S. F.; McEllistrem, M. T.; Yates, S. W.

    2015-10-01

    A critical-point has been proposed to exist within the shape/phase transition of the U(5), spherical, and O(6), γ-soft rotor, limits of the IBM. The xenon isotopes exhibit such a transition and have, therefore, been proposed as a chain in which to search for the E(5) critical-point symmetry. The candidacy for an E(5) nucleus has been largely based on the decays of the excited 0+ states, which for some of the xenon isotopes were not yet known. Inelastic neutron scattering measurements at the University of Kentucky Accelerator Laboratory have been performed using highly enriched (>99.9%) 130Xe, 132Xe, 134Xe and 136Xe gases converted to solid xenon difluorides. From these measurements, new excited 0+ states and their decays were identified, level lifetimes were measured, and transition probabilities were determined. This new information allows definitive conclusions to be drawn about the occurrence of the E(5) symmetry within the stable xenon isotopes. This material is based upon work supported by the U.S. National Science Foundation under Grant No. PHY-1305801.

  20. Human Regional Pulmonary Gas Exchange with Xenon Polarization Transfer (XTC)

    NASA Astrophysics Data System (ADS)

    Muradian, Iga; Butler, James; Hrovat, Mirko; Topulos, George; Hersman, Elizabeth; Ruset, Iulian; Covrig, Silviu; Frederick, Eric; Ketel, Stephen; Hersman, F. W.; Patz, Samuel

    2007-03-01

    Xenon Transfer Contrast (XTC) is an existing imaging method (Ruppert et al, Magn Reson Med, 51:676-687, 2004) that measures the fraction F of ^129Xe magnetization that diffuses from alveolar gas spaces to septal parenchymal tissue in lungs in a specified exchange time. As previously implemented, XTC is a 2-breath method and has been demonstrated in anesthetized animals. To use XTC in humans and to avoid issues associated with obtaining identical gas volumes on subsequent breath-hold experiments as well as precise image registration in post-processing, a single breath XTC method was developed that acquires three consecutive gradient echo images in an 8s acquisition. We report here initial measurements of the mean and variance of F for 5 normal healthy subjects as well as 7 asymptomatic smokers. The experiments were performed at two lung volumes (˜45 and 65% of TLC). We found that both the mean and variance of F increased with smoking history. In comparison, standard pulmonary function tests such as DLCO FEV1 showed no correlation with smoking history.

  1. A technique for administering xenon gas anesthesia during surgical procedures in mice.

    PubMed

    Ruder, Arne Mathias; Schmidt, Michaela; Ludiro, Alessia; Riva, Marco A; Gass, Peter

    2014-11-01

    Carrying out invasive procedures in animals requires the administration of anesthesia. Xenon gas offers advantages as an anesthetic agent compared with other agents, such as its protection of the brain and heart from hypoxia-induced damage. The high cost of xenon gas has limited its use as an anesthetic in animal experiments, however. The authors designed and constructed simple boxes for the induction and maintenance of xenon gas and isoflurane anesthesia in small rodents in order to minimize the amount of xenon gas that is wasted. While using their anesthesia delivery system to anesthetize pregnant mice undergoing caesarean sections, they measured the respiratory rates of the anesthetized mice, the survival of the pups and the percentages of oxygen and carbon dioxide within the system to confirm the system's safety.

  2. Double phase (liquid/gas) xenon scintillation detector for WIMPs direct search

    NASA Astrophysics Data System (ADS)

    Yamashita, M.; Doke, T.; Kikuchi, J.; Suzuki, S.

    2003-10-01

    A double phase (liquid/gas) xenon prototype detector of a 0.3 l active volume for WIMPs direct search has been constructed and tested. Proportional scintillation signals are observed by a multi-wire anode mounted in gas phase after ionization electrons drifted successfully long distance in liquid xenon. Both direct and proportional scintillation were used to discriminate electron recoil from nuclear recoil. Basic performances of the detector and the rejection efficiency of background gamma rays were demonstrated.

  3. Shock Compression of Cryogenic Noble Gas Mixtures: Xenon - Krypton

    NASA Astrophysics Data System (ADS)

    Root, Seth; Magyar, Rudolph; Lemke, Raymond; Mattsson, Thomas

    2013-06-01

    In past work, we have examined the multi-Mbar response of cryogenically cooled liquid xenon and liquid krypton measuring their Hugoniots to 8 Mbar. These results were utilized in the development of new EOS models for Xe and Kr to use in high energy density physics applications. The previous work demonstrated the usefulness of integrating high accuracy shock compression experiments with DFT to generate the basis for equation of state (EOS) models. In many physics applications, such as Z-pinch experiments, gas mixtures are used instead. However, we do not have reliable experimental data on these mixtures to provide informed decisions about the EOS models or mixture rules. To improve our understanding of mixtures at extreme conditions, we performed dynamic compression experiments using Sandia's Z - facility on a 70/30 molar ratio Kr/Xe cryogenically cooled liquid mixture. We measured the Hugoniot state and reshock state of the liquid mixture to several Mbar. The experimental data validated the DFT simulations for identical molar ratio mixtures. The combined experimental and DFT results are used to assess the EOS models and test the mixture rules. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000.

  4. Monte Carlo model for electron degradation in xenon gas

    PubMed Central

    Bhardwaj, Anil

    2016-01-01

    We have developed a Monte Carlo model for studying the local degradation of electrons in the energy range 9–10 000 eV in xenon gas. Analytically fitted form of electron impact cross sections for elastic and various inelastic processes are fed as input data to the model. The two-dimensional numerical yield spectrum (NYS), which gives information on the number of energy loss events occurring in a particular energy interval, is obtained as the output of the model. The NYS is fitted analytically, thus obtaining the analytical yield spectrum (AYS). The AYS can be used to calculate electron fluxes, which can be further employed for the calculation of volume production rates. Using the yield spectrum, mean energy per ion pair and efficiencies of inelastic processes are calculated. The value for mean energy per ion pair for Xe is 22 eV at 10 keV. Ionization dominates for incident energies greater than 50 eV and is found to have an efficiency of approximately 65% at 10 keV. The efficiency for the excitation process is approximately 30% at 10 keV. PMID:27118913

  5. AXEL-a high pressure xenon gas TPC for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Nakamura, Kiseki; Ichikawa, Atsuko K.; Nakaya, Tsuyoshi; Minamino, Akihiro; Ban, Sei; Yanagita, Saori; Tanaka, Shunsuke; Hirose, Masanori; Sekiya, Hiroyuki; Ueshima, Kota; Miuchi, Kentaro

    2017-02-01

    To search for neutrinoless double beta decay, we have started developing a high pressure xenon gas time projection chamber as the AXEL (A Xenon ElectroLuminescence detector) project since 2014. We proposed a new scheme to measure energy deposit using electroluminescence lights to achieve high energy resolution, large mass and strong background rejection power. Important performances of compositions of our new readout scheme are shown: electric field simulation, VUV sensitivity of MPPC in high pressure gaseous xenon, response of MPPC for large amount of photons. To demonstrate as a whole system, we constructed a small prototype detector using 64 MPPCs filled with 4 bar xenon gas. Result of measurement with a 57Co gamma-ray source are shown.

  6. An improved measurement of electron-ion recombination in high-pressure xenon gas

    NASA Astrophysics Data System (ADS)

    Serra, L.; Sorel, M.; Álvarez, V.; Borges, F. I. G.; Camargo, M.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Labarga, L.; Laing, A.; Liubarsky, I.; Lopez-March, N.; Lorca, D.; Losada, M.; Luzón, G.; Marí, A.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Pérez, J.; Pérez Aparicio, J. L.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, A.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Shuman, D.; Simón, A.; Sofka, C.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Villar, J. A.; Webb, R.; White, J. T.; Yahlali, N.

    2015-03-01

    We report on results obtained with the NEXT-DEMO prototype of the NEXT-100 high-pressure xenon gas time projection chamber (TPC), filled with pure xenon gas at 10 bar pressure and exposed to an alpha decay calibration source. Compared to our previous measurements with alpha particles, an upgraded detector and improved analysis techniques have been used. We measure event-by-event correlated fluctuations between ionization and scintillation due to electron-ion recombination in the gas, with correlation coefficients between -0.80 and -0.56 depending on the drift field conditions. By combining the two signals, we obtain a 2.8% FWHM energy resolution for 5.49 MeV alpha particles and a measurement of the optical gain of the electroluminescent TPC. The improved energy resolution also allows us to measure the specific activity of the radon in the gas due to natural impurities. Finally, we measure the average ratio of excited to ionized atoms produced in the xenon gas by alpha particles to be 0.561± 0.045, translating into an average energy to produce a primary scintillation photon of Wex=(39.2± 3.2) eV.

  7. Physiological response of rats to delivery of helium and xenon: implications for hyperpolarized noble gas imaging

    NASA Technical Reports Server (NTRS)

    Ramirez, M. P.; Sigaloff, K. C.; Kubatina, L. V.; Donahue, M. A.; Venkatesh, A. K.; Albert, M. S.; ALbert, M. S. (Principal Investigator)

    2000-01-01

    The physiological effects of various hyperpolarized helium and xenon MRI-compatible breathing protocols were investigated in 17 Sprague-Dawley rats, by continuous monitoring of blood oxygen saturation, heart rate, EKG, temperature and endotracheal pressure. The protocols included alternating breaths of pure noble gas and oxygen, continuous breaths of pure noble gas, breath-holds of pure noble gas for varying durations, and helium breath-holds preceded by two helium rinses. Alternate-breath protocols up to 128 breaths caused a decrease in oxygen saturation level of less than 5% for either helium or xenon, whereas 16 continuous-breaths caused a 31.5% +/- 2.3% decrease in oxygen saturation for helium and a 30.7% +/- 1. 3% decrease for xenon. Breath-hold protocols up to 25 s did not cause the oxygen saturation to fall below 90% for either of the noble gases. Oxygen saturation values below 90% are considered pathological. At 30 s of breath-hold, the blood oxygen saturation dropped precipitously to 82% +/- 0.6% for helium, and to 76.5% +/- 7. 4% for xenon. Breath-holds longer than 10 s preceded by pre-rinses caused oxygen saturation to drop below 90%. These findings demonstrate the need for standardized noble gas inhalation procedures that have been carefully tested, and for continuous physiological monitoring to ensure the safety of the subject. We find short breath-hold and alternate-breath protocols to be safe procedures for use in hyperpolarized noble gas MRI experiments. Copyright 2000 John Wiley & Sons, Ltd.

  8. Physiological response of rats to delivery of helium and xenon: implications for hyperpolarized noble gas imaging

    NASA Technical Reports Server (NTRS)

    Ramirez, M. P.; Sigaloff, K. C.; Kubatina, L. V.; Donahue, M. A.; Venkatesh, A. K.; Albert, M. S.; ALbert, M. S. (Principal Investigator)

    2000-01-01

    The physiological effects of various hyperpolarized helium and xenon MRI-compatible breathing protocols were investigated in 17 Sprague-Dawley rats, by continuous monitoring of blood oxygen saturation, heart rate, EKG, temperature and endotracheal pressure. The protocols included alternating breaths of pure noble gas and oxygen, continuous breaths of pure noble gas, breath-holds of pure noble gas for varying durations, and helium breath-holds preceded by two helium rinses. Alternate-breath protocols up to 128 breaths caused a decrease in oxygen saturation level of less than 5% for either helium or xenon, whereas 16 continuous-breaths caused a 31.5% +/- 2.3% decrease in oxygen saturation for helium and a 30.7% +/- 1. 3% decrease for xenon. Breath-hold protocols up to 25 s did not cause the oxygen saturation to fall below 90% for either of the noble gases. Oxygen saturation values below 90% are considered pathological. At 30 s of breath-hold, the blood oxygen saturation dropped precipitously to 82% +/- 0.6% for helium, and to 76.5% +/- 7. 4% for xenon. Breath-holds longer than 10 s preceded by pre-rinses caused oxygen saturation to drop below 90%. These findings demonstrate the need for standardized noble gas inhalation procedures that have been carefully tested, and for continuous physiological monitoring to ensure the safety of the subject. We find short breath-hold and alternate-breath protocols to be safe procedures for use in hyperpolarized noble gas MRI experiments. Copyright 2000 John Wiley & Sons, Ltd.

  9. Ba-ion extraction and identification from high pressure Xenon gas for nEXO

    NASA Astrophysics Data System (ADS)

    Lan, Yang; Brunner, Thomas; Fudenberg, Daniel; Varentsov, Victor; Dilling, Jens; Gratta, Giorgio; nEXO Collaboration

    2016-09-01

    The Enriched Xenon Observatory (EXO) is searching for the lepton-number violating double beta decay (0 νββ) in 136Xe. If experimentally confirmed, 0 νββ will require the neutrino to be a MAJORANA particle, and shed light on the neutrino-mass hierarchy. The currently running EXO-200 experiment has obtained the limit of T1/ 2 0 νββ >= 1 . 1 ×1025 years. In parallel, the development of nEXO has started and is expected to probe the inverted mass hierarchy of neutrino. One of the design goals of nEXO is to unambiguously differentiate true double beta decay events from background contributions through Ba-tagging, i.e. by identifying the daughter isotope 136Ba. With an efficient Ba-Tagging technique, the backgournds can be virtually eliminated. A setup is being developed for Ba-tagging in xenon gas. Its central component is an RF-funnel to extract Ba-ions from high pressure xenon gas (up to 10 bar). The second stage, a linear Paul trap, cools the ions through buffer gas and bunches them into a multi-reflection time-of-flight mass spectrometer for ion identification. The RF-funnel has been built and tested. The liner Paul trap is currently under development. The Ba-tagging setup will be presented and future works will be discussed.

  10. Stable xenon CT blood flow mapping for evaluation of patients with extracranial-intracranial bypass surgery

    SciTech Connect

    Yonas, H.; Gur, D.; Good, B.C.; Latchaw, R.E.; Wolfson, S.K. Jr.; Good, W.F.; Maitz, G.S.; Colsher, J.G.; Barnes, J.E.; Colliander, K.G.

    1985-03-01

    Xenon computerized tomography (Xe CT) blood flow studies were conducted in 25 patients referred for a possible extracranial-intracranial bypass procedure for occlusive vascular disease in one or more extra- or intracranial vessels. These studies were helpful in selecting eight candidates for surgery. The Xe CT studies were performed at one or two brain levels using a prototype Xe CT system for measurement of cerebral blood flow which was designed in collaboration with the General Electric Co., and adapted for the GE 9800 scanner. In those patients selected to undergo operation, Xe CT demonstrated compromise of flow reserve regionally, globally, and/or in the watershed area. All eight patients who underwent the procedure showed a favorable clinical response postoperatively, and seven had a dramatic increase in flow. The 17 patients whose baseline CT studies showed no reduction of flow with the Xe CT method were not selected for surgery. All 25 patients have remained neurologically stable to date. Case studies of three of the eight patients undergoing bypass surgery are presented. This limited but consistent experience suggests that Xe CT blood flow mapping makes possible the recognition of brain regions in which flow reserves are compromised. This is due to the relatively high degree of spatial resolution that this technique provides and to the fact that mapping can be correlated directly with the anatomy. Used in combination with a careful clinical examination and an accurate medical history, this study method appears to be a useful guide in the selection of patients who are most at risk from hemodynamic instability and those who are most likely to benefit from flow-augmentation surgery.

  11. Generation of soft x-ray radiation by laser irradiation of a gas puff xenon target

    SciTech Connect

    Fiedorowicz, H.; Bartnik, A.; Szczurek, M.

    1995-12-31

    Plasmas produced from laser-irradiated gas puff xenon targets, created by pulsed injection of xenon with high-pressure solenoid valve, offer the possibility of realizing a debrisless x-ray point source for the x-ray lithography applications. In this paper the authors present results of the experimental investigations on the x-ray generation from a gas puff xenon target irradiated with nanosecond high-power laser pulses produced using two different laser facilities: a Nd:glass laser operating at 1.06 {micro}m, which generated 10--15 J pulses in 1 ns FWHM, and Nd:glass slab laser, producing pulses of 10 ns duration with energy reaching 12 J for a 0.53 {micro}m wavelength or 20 J for 1.05 {micro}m. To study the x-ray emission different x-ray diagnostic methods have been used. X-ray spectra were registered using a flat CsAP crystal spectrograph with an x-ray film or a curved KAP crystal spectrograph with a convex curvature to an x-ray CCD readout detector. X-ray images have been taken using pinhole cameras with an x-ray film or a CCD array. X-ray yield was measured with the use of semiconductor detectors (silicon photodiodes or diamond photoconductors).

  12. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    SciTech Connect

    Chu, X. X.; Zhang, D. X.; Qian, Y.; Liu, W.; Zhang, M. M.; Xu, D.

    2014-01-29

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in helium recycle gas are less than 1 ppb.

  13. Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

    NASA Astrophysics Data System (ADS)

    Chu, X. X.; Zhang, M. M.; Zhang, D. X.; Xu, D.; Qian, Y.; Liu, W.

    2014-01-01

    In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H2 from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H2 in helium recycle gas are less than 1 ppb.

  14. AXEL : Neutrinoless double beta decay search with a high pressure xenon gas Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Ban, Sei; AXEL collaboration

    2017-09-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. It is operated at the proportional scintillation mode. We have developed a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used to reduce background. The project is in a R&D phase, and we report the current status of our prototype chamber with 10 L and 4 bar Xe gas.

  15. Fitting formula for the injection volume of a gas chromatograph for radio-xenon sampling in the lower troposphere.

    PubMed

    Shu-jiang, Liu; Zhan-ying, Chen; Shi-lian, Wang; Yin-zhong, Chang; Qi, Li; Yuan-qing, Fan; Yun-gang, Zhao; Huai-mao, Jia; Xin-jun, Zhang; Jun, Wang

    2014-06-01

    GC is usually used for xenon concentration and radon removal in the International Monitoring System of the Comprehensive Nuclear-Test-Ban Treaty. In a gas chromatograph, the injection volume is defined to calculate the column capacity. In this paper, the injection volume was investigated and a fitting formula for the injection volume was derived and discussed subsequently. As a consequence, the xenon injection volume exponentially decreased with the column temperature increased, but exponentially increased as the flow rate increased.

  16. A novel 83mKr tracer method for characterizing xenon gas and cryogenic distillation systems

    NASA Astrophysics Data System (ADS)

    Rosendahl, S.; Bokeloh, K.; Brown, E.; Cristescu, I.; Fieguth, A.; Huhmann, C.; Lebeda, O.; Levy, C.; Murra, M.; Schneider, S.; V'enos, D.; Weinheimer, C.

    2014-10-01

    The radioactive isomer 83mKr, has many properties that make it very useful for various applications. Its low energy decay products, like conversion, shake-off and Auger electrons as well as X- and γ-rays are used for calibration purposes in neutrino mass experiments and direct dark matter detection experiments. Thanks to the short half-life of 1.83 h and the decay to the ground state 83Kr, one does not risk contamination of any low-background experiment with long-lived radionuclides. In this paper, we present a new approach, using 83mKr as a radioactive tracer in noble gases. A method of doping 83mKr, into xenon gas and its detection, using special custom-made detectors, based on a photomultiplier tube, is described. Two applications of this method are presented: firstly, it can be used to characterize the particle flow inside of gas routing systems and determine the circulation speed of gas particles inside of a gas purification system for xenon. Secondly, it is used for rapid estimating of the separation performance of a distillation system.

  17. Development and evaluation of a silver mordenite composite sorbent for the partitioning of xenon from krypton in gas compositions

    SciTech Connect

    Garn, Troy G.; Greenhalgh, Mitchell; Law, Jack D.

    2015-12-22

    A new engineered form composite sorbent for the selective separation of xenon from krypton in simulant composition off-gas streams resulting from the reprocessing of used nuclear fuel has been developed and evaluated. A sodium mordenite powder was incorporated into a macroporous polymer binder, formed into spherical beads and successfully converted to a 9 wt.% silver form composite sorbent. The final engineered form sorbent retained the characteristic surface area indicative of sodium mordenite powder. The sorbent was evaluated for xenon adsorption potential with capacities measured as high as 30 millimoles of xenon per kilogram of sorbent achieved at ambient temperature and 460 millimoles of xenon per kilogram sorbent at 220 K. Xenon/krypton selectivity was calculated to be 22.4 with a 1020 µL/L xenon, 150 µL/L krypton in a balance of air feed gas at 220 K. Furthermore, adsorption/desorption thermal cycling effects were evaluated with results indicating sorbent performance was not significantly impacted while undergoing numerous adsorption/desorption thermal cycles.

  18. Development and evaluation of a silver mordenite composite sorbent for the partitioning of xenon from krypton in gas compositions

    DOE PAGES

    Garn, Troy G.; Greenhalgh, Mitchell; Law, Jack D.

    2015-12-22

    A new engineered form composite sorbent for the selective separation of xenon from krypton in simulant composition off-gas streams resulting from the reprocessing of used nuclear fuel has been developed and evaluated. A sodium mordenite powder was incorporated into a macroporous polymer binder, formed into spherical beads and successfully converted to a 9 wt.% silver form composite sorbent. The final engineered form sorbent retained the characteristic surface area indicative of sodium mordenite powder. The sorbent was evaluated for xenon adsorption potential with capacities measured as high as 30 millimoles of xenon per kilogram of sorbent achieved at ambient temperature andmore » 460 millimoles of xenon per kilogram sorbent at 220 K. Xenon/krypton selectivity was calculated to be 22.4 with a 1020 µL/L xenon, 150 µL/L krypton in a balance of air feed gas at 220 K. Furthermore, adsorption/desorption thermal cycling effects were evaluated with results indicating sorbent performance was not significantly impacted while undergoing numerous adsorption/desorption thermal cycles.« less

  19. Characteristics of a high pressure gas proportional counter filled with xenon

    NASA Technical Reports Server (NTRS)

    Sakurai, H.; Ramsey, B. D.

    1991-01-01

    The characteristics of a conventional cylindrical geometry proportional counter filled with high pressure xenon gas up to 10 atm. were fundamentally investigated for use as a detector in hard X-ray astronomy. With a 2 percent methane gas mixture the energy resolutions at 10 atm. were 9.8 percent and 7.3 percent for 22 keV and 60 keV X-rays, respectively. From calculations of the Townsend ionization coefficient, it is shown that proportional counters at high pressure operate at weaker reduced electric field than low pressure counters. The characteristics of a parallel grid proportional counter at low pressure showed similar pressure dependence. It is suggested that this is the fundamental reason for the degradation of resolution observed with increasing pressure.

  20. A Method for Calculating Viscosity and Thermal Conductivity of a Helium-Xenon Gas Mixture

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.

    2006-01-01

    A method for calculating viscosity and thermal conductivity of a helium-xenon (He-Xe) gas mixture was employed, and results were compared to AiResearch (part of Honeywell) analytical data. The method of choice was that presented by Hirschfelder with Singh's third-order correction factor applied to thermal conductivity. Values for viscosity and thermal conductivity were calculated over a temperature range of 400 to 1200 K for He-Xe gas mixture molecular weights of 20.183, 39.94, and 83.8 kg/kmol. First-order values for both transport properties were in good agreement with AiResearch analytical data. Third-order-corrected thermal conductivity values were all greater than AiResearch data, but were considered to be a better approximation of thermal conductivity because higher-order effects of mass and temperature were taken into consideration. Viscosity, conductivity, and Prandtl number were then compared to experimental data presented by Taylor.

  1. Simultaneous detection of xenon and krypton in equine plasma by gas chromatography-tandem mass spectrometry for doping control.

    PubMed

    Kwok, Wai Him; Choi, Timmy L S; So, Pui-Kin; Yao, Zhong-Ping; Wan, Terence S M

    2017-02-01

    Xenon can activate the hypoxia-inducible factors (HIFs). As such, it has been allegedly used in human sports for increasing erythropoiesis. Krypton, another noble gas with reported narcosis effect, can also be expected to be a potential and less expensive erythropoiesis stimulating agent. This has raised concern about the misuse of noble gases as doping agents in equine sports. The aim of the present study is to establish a method for the simultaneous detection of xenon and krypton in equine plasma for the purpose of doping control. Xenon- or krypton-fortified equine plasma samples were prepared according to reported protocols. The target noble gases were simultaneously detected by gas chromatography-triple quadrupole mass spectrometry using headspace injection. Three xenon isotopes at m/z 129, 131, and 132, and four krypton isotopes at m/z 82, 83, 84, and 86 were targeted in selected reaction monitoring mode (with the precursor ions and product ions at identical mass settings), allowing unambiguous identification of the target analytes. Limits of detection for xenon and krypton were about 19 pmol/mL and 98 pmol/mL, respectively. Precision for both analytes was less than 15%. The method has good specificity as background analyte signals were not observed in negative equine plasma samples (n = 73). Loss of analytes under different storage temperatures has also been evaluated. Copyright © 2016 John Wiley & Sons, Ltd.

  2. When the dust settles: stable xenon isotope constraints on the formation of nuclear fallout.

    PubMed

    Cassata, W S; Prussin, S G; Knight, K B; Hutcheon, I D; Isselhardt, B H; Renne, P R

    2014-11-01

    Nuclear weapons represent one of the most immediate threats of mass destruction. In the event that a procured or developed nuclear weapon is detonated in a populated metropolitan area, timely and accurate nuclear forensic analysis and fallout modeling would be needed to support attribution efforts and hazard assessments. Here we demonstrate that fissiogenic xenon isotopes retained in radioactive fallout generated by a nuclear explosion provide unique constraints on (1) the timescale of fallout formation, (2) chemical fractionation that occurs when fission products and nuclear fuel are incorporated into fallout, and (3) the speciation of fission products in the fireball. Our data suggest that, in near surface nuclear tests, the presence of a significant quantity of metal in a device assembly, combined with a short time allowed for mixing with the ambient atmosphere (seconds), may prevent complete oxidation of fission products prior to their incorporation into fallout. Xenon isotopes thus provide a window into the chemical composition of the fireball in the seconds that follow a nuclear explosion, thereby improving our understanding of the physical and thermo-chemical conditions under which fallout forms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. An automated multidimensional preparative gas chromatographic system for isolation and enrichment of trace amounts of xenon from ambient air.

    PubMed

    Larson, Tuula; Östman, Conny; Colmsjö, Anders

    2011-04-01

    The monitoring of radioactive xenon isotopes is one of the principal methods for the detection of nuclear explosions in order to identify clandestine nuclear testing. In this work, a miniaturized, multiple-oven, six-column, preparative gas chromatograph was constructed in order to isolate trace quantities of radioactive xenon isotopes from ambient air, utilizing nitrogen as the carrier gas. The multidimensional chromatograph comprised preparative stainless steel columns packed with molecular sieves, activated carbon, and synthetic carbon adsorbents (e.g., Anasorb®-747 and Carbosphere®). A combination of purification techniques--ambient adsorption, thermal desorption, back-flushing, thermal focusing, and heart cutting--was selectively optimized to produce a well-defined xenon peak that facilitated reproducible heart cutting and accurate quantification. The chromatographic purification of a sample requires approximately 4 h and provides complete separation of xenon from potentially interfering components (such as water vapor, methane, carbon dioxide, and radon) with recovery and accuracy close to 100%. The preparative enrichment process isolates and concentrates a highly purified xenon gas fraction that is suitable for subsequent ultra-low-level γ-, ß/γ-spectroscopic or high-resolution mass spectrometric measurement (e.g., to monitor the gaseous fission products of nuclear explosions at remote locations). The Xenon Processing Unit is a free-standing, relatively lightweight, and transportable system that can be interfaced to a variety of sampling and detection systems. It has a relatively inexpensive, rugged, and compact modular (19-inch rack) design that provides easy access to all parts for maintenance and has a low power requirement.

  4. Mesoscale Backtracking by Means of Atmospheric Transport Modeling of Xenon Plumes Measured by Radionuclide Gas Stations

    NASA Astrophysics Data System (ADS)

    Armand, P. P.; Achim, P.; Taffary, T.

    2006-12-01

    The monitoring of atmospheric radioactive xenon concentration is performed for nuclear safety regulatory requirements. It is also planned to be used for the detection of hypothetical nuclear tests in the framework of the Comprehensive nuclear-Test-Ban Treaty (CTBT). In this context, the French Atomic Energy Commission designed a high sensitive and automated fieldable station, named SPALAX, to measure the activity concentrations of xenon isotopes in the atmosphere. SPALAX stations were set up in Western Europe and have been operated quite continuously for three years or more, detecting principally xenon-133 and more scarcely xenon-135, xenon-133m and xenon-131m. There are around 150 nuclear power plants in the European Union, research reactors, reprocessing plants, medical production and application facilities releasing radioactive xenon in normal or incidental operations. A numerical study was carried out aiming to explain the SPALAX measurements. The mesoscale Atmospheric Transport Modelling involves the MM5 suite (PSU- NCAR) to predict the wind fields on nested domains, and FLEXPART, a 3D Lagrangian particle dispersion code, used to simulate the backward transport of xenon plumes detected by the SPALAX. For every event of detection, at least one potential xenon source has a significant efficiency of emission. The identified likely sources are located quite close to the SPALAX stations (some tens of kilometres), or situated farther (a few hundreds of kilometres). A base line of some mBq per cubic meter in xenon-133 is generated by the nuclear power plants. Peaks of xenon-133 ranging from tens to hundreds of mBq per cubic meter originate from a radioisotope production facility. The calculated xenon source terms required to obtain the SPALAX measurements are discussed and seem consistent with realistic emissions from the xenon sources in Western Europe.

  5. Spatial characterization of extreme ultraviolet plasmas generated by laser excitation of xenon gas targets

    NASA Astrophysics Data System (ADS)

    Kranzusch, Sebastian; Peth, Christian; Mann, Klaus

    2003-02-01

    At Laser-Laboratorium Göttingen laser-plasma sources were tested, which are going to be used for characterization of optical components and sensoric devices in the wavelength region from 11 to 13 nm. In all cases extreme ultraviolet (EUV) radiation is generated by focusing a Q-switched Nd:YAG laser into a pulsed gas puff target. By the use of xenon or oxygen as target gas, broadband as well as narrowband EUV radiation is obtained, respectively. Different types of valves and nozzles were tested in order to optimize the emitted radiation with respect to maximum EUV intensities, small source diameters, and positional stability. The investigation of these crucial source parameters was performed with specially designed EUV pinhole cameras, utilizing evaluation algorithms developed for standardized laser beam characterization. In addition, a rotatable pinhole camera was developed which allows both spatially and angular resolved monitoring of the soft x-ray emission characteristics. With the help of this camera a strong angular dependence of the EUV intensity was found. The data were compared with fluorescence measurements for visualization of the target gas jet. The experimental observations can be explained by reabsorption of the generated EUV radiation in the surrounding target gas, as supported by semiempirical model calculations based on the attenuation in the three-dimensional gas density according to Lambert-Beer's law. As a consequence of the presented investigations, an optimization of the EUV source with respect to intensity, plasma shape, and angular dependence is achieved, resulting in a spherical plasma of 200 μm diameter and a 50% increase of the EUV pulse energy.

  6. Hyperpolarized Xenon-129 Gas-Exchange Imaging of Lung Microstructure: First Case Studies in Subjects with Obstructive Lung Disease

    PubMed Central

    Dregely, Isabel; Mugler, John P.; Ruset, Iulian C.; Altes, Talissa A.; Mata, Jaime F.; Miller, G. Wilson; Ketel, Jeffrey; Ketel, Steve; Distelbrink, Jan; Hersman, F.W.; Ruppert, Kai

    2011-01-01

    Purpose To develop and test a method to non-invasively assess the functional lung microstructure. Materials and Methods The Multiple exchange time Xenon polarization Transfer Contrast technique (MXTC) encodes xenon gas-exchange contrast at multiple delay times permitting two lung-function parameters to be derived: 1) MXTC-F, the long exchange-time depolarization value, which is proportional to the tissue to alveolar-volume ratio and 2) MXTC-S, the square root of the xenon exchange-time constant, which characterizes thickness and composition of alveolar septa. Three healthy volunteers, one asthmatic and two COPD (GOLD stage I and II) subjects were imaged with MXTC MRI. In a subset of subjects, hyperpolarized xenon-129 ADC MRI and CT imaging were also performed. Results The MXTC-S parameter was found to be elevated in subjects with lung disease (p-value = 0.018). In the MXTC-F parameter map it was feasible to identify regional loss of functional tissue in a COPD patient. Further, the MXTC-F map showed excellent regional correlation with CT and ADC (ρ ≥ 0.90) in one COPD subject. Conclusion The functional tissue-density parameter MXTC-F showed regional agreement with other imaging techniques. The newly developed parameter MXTC-S, which characterizes the functional thickness of alveolar septa, has potential as a novel biomarker for regional parenchymal inflammation or thickening. PMID:21509861

  7. Xenon Isotope Releases from Buried Transuranic Waste

    NASA Astrophysics Data System (ADS)

    Dresel, P. E.; Waichler, S. R.; Kennedy, B. M.; Hayes, J. C.; McIntyre, J. I.; Giles, J. R.; Sondrup, A. J.

    2004-12-01

    Xenon is an inert rare gas produced as a fission product in nuclear reactors and through spontaneous fission of some transuranic isotopes. Thus, xenon will be released from buried transuranic waste. Two complementary methods are used to measure xenon isotopes: radiometric analysis for short-lived radioxenon isotopes and mass spectrometry for detection of stable xenon isotopes. Initial measurements near disposal facilities at the U.S. Department of Energy's Hanford Site show radioxenon and stable xenon isotopic signatures that are indicative of transuranic waste. Radioxenon analysis has greater sensitivity due to the lower background concentrations and indicates spontaneous fission due to the short half life of the isotopes. Stable isotope ratios may be used to distinguish irradiated fuel sources from pure spontaneous fission sources and are not as dependent on rapid release from the waste form. The release rate is dependent on the type of waste and container integrity and is the greatest unknown in application of this technique. Numerical multi-phase transport modeling of burial grounds at the Idaho National Engineering and Environmental Laboratory indicates that, under generalized conditions, the radioxenon isotopes will diffuse away from the waste and be found in the soil cap and adjacent to the burial ground at levels many orders of magnitude above the detection limit.

  8. Low-energy ion emission from a xenon gas-puff laser-plasma X-ray source

    NASA Astrophysics Data System (ADS)

    Daido, H.; Yamagami, S.; Suzuki, M.; Azuma, H.; Choi, I. W.; Fiedorowicz, H.

    We have measured low-energy ion emission from a gas-puff laser-plasma X-ray source. The ions may cause the degradation of the condenser mirror of the extreme ultra-violet projection lithography system. A 0.7 J in 8 ns Nd:YAG laser at 1.06 μm was focused onto the xenon gas-puff target with an intensity of 1012 W/cm2. The silicon (111) plates, placed at a distance of 32 mm from the laser-interaction region, were exposed with the xenon ions. The average ion energy was measured to be less than 50 eV with a Faraday-cup detector placed close to the silicon plates. The xenon deposition occurred in the silicon plates with a depth of less than 40 nm. The deposition density was measured with a quadrupole secondary ion mass spectrometer to be 1021 /cm3 after 1500 laser shots. The energy-conversion efficiency from the laser energy into the ions is 0.1%/4 πsr/shot. For the lithography system, if we can remove such ion bombardment completely using novel techniques such as electro-magnetic devices or gas flow curtain techniques, the lifetime of the condenser mirror will be extended significantly.

  9. THEORETICAL STUDY ON THE INTERACTION BETWEEN XENON AND POSITIVE SILVER CLUSTERS IN GAS PHASE AND ON THE (001) CHABAZITE SURFACE

    SciTech Connect

    Hunter, D.

    2009-03-16

    A systematic study on the adsorption of xenon on silver clusters in the gas phase and on the (001) surface of silver-exchanged chabazite is reported. Density functional theory at the B3LYP level with the cluster model was employed. The results indicate that the dominant part of the binding is the {sigma} donation, which is the charge transfer from the 5p orbital of Xe to the 5s orbital of Ag and is not the previously suggested d{sub {pi}}-d{sub {pi}} back-donation. A correlation between the binding energy and the degree of {sigma} donation is found. Xenon was found to bind strongly to silver cluster cations and not to neutral ones. The binding strength decreases as the cluster size increases for both cases, clusters in the gas-phase and on the chabazite surface. The Ag{sup +} cation is the strongest binding site for xenon both in gas phase and on the chabazite surface with the binding energies of 73.9 and 14.5 kJ/mol, respectively. The results also suggest that the smaller silver clusters contribute to the negative chemical shifts observed in the {sup 129}Xe NMR spectra in experiments.

  10. Dark matter directionality revisited with a high pressure xenon gas detector

    SciTech Connect

    Mohlabeng, Gopolang; Kong, Kyoungchul; Li, Jin; Para, Adam; Yoo, Jonghee

    2015-07-20

    An observation of the anisotropy of dark matter interactions in a direction-sensitive detector would provide decisive evidence for the discovery of galactic dark matter. Directional information would also provide a crucial input to understanding its distribution in the local Universe. Most of the existing directional dark matter detectors utilize particle tracking methods in a low-pressure gas time projection chamber. These low pressure detectors require excessively large volumes in order to be competitive in the search for physics beyond the current limit. In order to avoid these volume limitations, we consider a novel proposal, which exploits a columnar recombination effect in a high-pressure gas time projection chamber. The ratio of scintillation to ionization signals observed in the detector carries the angular information of the particle interactions. In this paper, we investigate the sensitivity of a future directional detector focused on the proposed high-pressure Xenon gas time projection chamber. We study the prospect of detecting an anisotropy in the dark matter velocity distribution. We find that tens of events are needed to exclude an isotropic distribution of dark matter interactions at 95% confidence level in the most optimistic case with head-to-tail information. However, one needs at least 10-20 times more events without head-to-tail information for light dark matter below ~50 GeV. For an intermediate mass range, we find it challenging to observe an anisotropy of the dark matter distribution. Our results also show that the directional information significantly improves precision measurements of dark matter mass and the elastic scattering cross section for a heavy dark matter.

  11. Dark matter directionality revisited with a high pressure xenon gas detector

    DOE PAGES

    Mohlabeng, Gopolang; Kong, Kyoungchul; Li, Jin; ...

    2015-07-20

    An observation of the anisotropy of dark matter interactions in a direction-sensitive detector would provide decisive evidence for the discovery of galactic dark matter. Directional information would also provide a crucial input to understanding its distribution in the local Universe. Most of the existing directional dark matter detectors utilize particle tracking methods in a low-pressure gas time projection chamber. These low pressure detectors require excessively large volumes in order to be competitive in the search for physics beyond the current limit. In order to avoid these volume limitations, we consider a novel proposal, which exploits a columnar recombination effect inmore » a high-pressure gas time projection chamber. The ratio of scintillation to ionization signals observed in the detector carries the angular information of the particle interactions. In this paper, we investigate the sensitivity of a future directional detector focused on the proposed high-pressure Xenon gas time projection chamber. We study the prospect of detecting an anisotropy in the dark matter velocity distribution. We find that tens of events are needed to exclude an isotropic distribution of dark matter interactions at 95% confidence level in the most optimistic case with head-to-tail information. However, one needs at least 10-20 times more events without head-to-tail information for light dark matter below ~50 GeV. For an intermediate mass range, we find it challenging to observe an anisotropy of the dark matter distribution. Our results also show that the directional information significantly improves precision measurements of dark matter mass and the elastic scattering cross section for a heavy dark matter.« less

  12. Modelling the behaviour of microbulk Micromegas in xenon/trimethylamine gas

    NASA Astrophysics Data System (ADS)

    Ruiz-Choliz, E.; González-Díaz, D.; Diago, A.; Castel, J.; Dafni, T.; Herrera, D. C.; Iguaz, F. J.; Irastorza, I. G.; Luzón, G.; Mirallas, H.; Şahin, Ö.; Veenhof, R.

    2015-11-01

    We model the response of a state of the art micro-hole single-stage charge amplification device ('microbulk' Micromegas) in a gaseous atmosphere consisting of xenon/trimethylamine at various concentrations and pressures. The amplifying structure, made with photo-lithographic techniques similar to those followed in the fabrication of gas electron multipliers (GEMs), consisted of a 100 μm-side equilateral-triangle pattern with 50 μm-diameter holes placed at its vertexes. Once the primary electrons are guided into the holes by virtue of an optimized field configuration, avalanches develop along the 50 μm-height channels etched out of the original doubly copper-clad polyimide foil. In order to properly account for the strong field gradients at the holes' entrance as well as for the fluctuations of the avalanche process (that ultimately determine the achievable energy resolution), we abandoned the hydrodynamic framework, resorting to a purely microscopic description of the electron trajectories as obtained from elementary cross-sections. We show that achieving a satisfactory description needs additional assumptions about atom-molecule (Penning) transfer reactions and charge recombination to be made.

  13. Cerebral blood flow determination within the first 8 hours of cerebral infarction using stable xenon-enhanced computed tomography

    SciTech Connect

    Hughes, R.L.; Yonas, H.; Gur, D.; Latchaw, R.

    1989-06-01

    Cerebral blood flow mapping with stable xenon-enhanced computed tomography (Xe/CT) was performed in conjunction with conventional computed tomography (CT) within the first 8 hours after the onset of symptoms in seven patients with cerebral infarction. Six patients had hemispheric infarctions, and one had a progressive brainstem infarction. Three patients with very low (less than 10 ml/100 g/min) blood flow in an anatomic area appropriate for the neurologic deficit had no clinical improvement by the time of discharge from the hospital; follow-up CT scans of these three patients confirmed infarction in the area of very low blood flow. Three patients with moderate blood flow reductions (15-45 ml/100 g/min) in the appropriate anatomic area had significant clinical improvement from their initial deficits and had normal follow-up CT scans. One patient studied 8 hours after stroke had increased blood flow (hyperemia) in the appropriate anatomic area and made no clinical recovery.

  14. The narrow pulse approximation and long length scale determination in xenon gas diffusion NMR studies of model porous media

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Sen, P. N.; Hurlimann, M. D.; Patz, S.; Cory, D. G.; Walsworth, R. L.

    2002-01-01

    We report a systematic study of xenon gas diffusion NMR in simple model porous media, random packs of mono-sized glass beads, and focus on three specific areas peculiar to gas-phase diffusion. These topics are: (i) diffusion of spins on the order of the pore dimensions during the application of the diffusion encoding gradient pulses in a PGSE experiment (breakdown of the narrow pulse approximation and imperfect background gradient cancellation), (ii) the ability to derive long length scale structural information, and (iii) effects of finite sample size. We find that the time-dependent diffusion coefficient, D(t), of the imbibed xenon gas at short diffusion times in small beads is significantly affected by the gas pressure. In particular, as expected, we find smaller deviations between measured D(t) and theoretical predictions as the gas pressure is increased, resulting from reduced diffusion during the application of the gradient pulse. The deviations are then completely removed when water D(t) is observed in the same samples. The use of gas also allows us to probe D(t) over a wide range of length scales and observe the long time asymptotic limit which is proportional to the inverse tortuosity of the sample, as well as the diffusion distance where this limit takes effect (approximately 1-1.5 bead diameters). The Pade approximation can be used as a reference for expected xenon D(t) data between the short and the long time limits, allowing us to explore deviations from the expected behavior at intermediate times as a result of finite sample size effects. Finally, the application of the Pade interpolation between the long and the short time asymptotic limits yields a fitted length scale (the Pade length), which is found to be approximately 0.13b for all bead packs, where b is the bead diameter. c. 2002 Elsevier Sciences (USA).

  15. Formation of Structured Water and Gas Hydrate by the Use of Xenon Gas in Vegetable Tissue

    NASA Astrophysics Data System (ADS)

    Ando, Hiroko; Suzuki, Toru; Kawagoe, Yoshinori; Makino, Yoshio; Oshita, Seiichi

    Freezing is a valuable technique for food preservation. However, vegetables are known to be softening remarkably after freezing and thawing process. It is expected to find alternative technique instead of freezing. Recently, the application of structured water and/or gas hydrate had been attempted to prolong the preservation of vegetable. In this study, the formation process of structure water and/or gas hydrate in pure water and carrot tissue was investigated by using NMR relaxation times, T1 and T2, of which applying condition was up to 0.4MPa and 0.8MPa at 5oC. Under the pressure of 0.4MPa, no gas hydrate was appeared, however, at 0.8MPa, formation of gas hydrate was recognized in both water and carrot tissue. Once the gas hydrate formation process in carrot tissue started, T1 and T2 increased remarkably. After that, as the gas hydrate developed, then T1 and T2 turned to decrease. Since this phenomenon was not observed in pure water, it is suggested that behavior of NMR relaxation time just after the formation of gas hydrate in carrot tissue may be peculiar to compartment system such as inter and intracellular spaces.

  16. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Because xenon near the critical point will collapse under its own weight, experiments on Earth (green line) are limited as they get closer (toward the left) to the critical point. CVX in the microgravity of space (red line) moved into unmeasured territory that scientists had not been able to reach.

  17. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The sample cell at the heart of CVX-2 will sit inside a thermostat providing three layers of insulation. The cell itself comprises a copper body that conducts heat efficiently and smoothes out thermal variations that that would destroy the xenon's uniformity. Inside the cell, the oscillating screen viscometer element is supported between two pairs of electrodes that deflect the screen and then measure screen motion.

  18. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Because xenon near the critical point will collapse under its own weight, experiments on Earth (green line) are limited as they get closer (toward the left) to the critical point. CVX in the microgravity of space (red line) moved into unmeasured territory that scientists had not been able to reach.

  19. Spatial coherence measurements of the EUV emission from laser-plasma source based on xenon/helium gas puff target

    NASA Astrophysics Data System (ADS)

    Wachulak, P.; Sarzyński, A.; Bartnik, A.; Fok, T.; Węgrzynski, Ł.; Kostecki, J.; Fiedorowicz, H.

    2017-08-01

    In this paper, we present the first measurements of the partial spatial coherence of the EUV emission from xenon plasma in laser-plasma source, based on a double stream gas puff target. The Young double slit approach was employed to measure complex coherence factor of the EUV Xe emission at 13.5-nm wavelength in two orthogonal directions. The radius of coherence of 60 μm was estimated at the distance of 2.1 m from the source. The number of coherently emitted photons was sufficient to demonstrate coherent imaging. Using partially coherent radiation from such source Gabor EUV holography was successfully demonstrated.

  20. High-pressure Xenon Gas Electroluminescent TPC Concept for Simultaneous Searches for Neutrino-less Double Beta Decay & WIMP Dark Matter

    NASA Astrophysics Data System (ADS)

    Nygren, David

    2013-04-01

    Xenon is an especially attractive candidate for both direct WIMP and 0- decay searches. Although the current trend has exploited the liquid phase, gas phase xenon offers some remarkable performance advantages for energy resolution, topology visualization, and discrimination between electron and nuclear recoils. The NEXT-100 experiment, now beginning construction in the Canfranc Underground Laboratory, Spain, will operate at 12 bars with 100 kg of ^136Xe for the 0- decay search. I will describe recent results with small prototypes, indicating that NEXT-100 can provide about 0.5% FWHM energy resolution at the decay 2457.83 keV Q-value, as well as rejection of -rays by topology. However, sensitivity goals for WIMP dark matter and 0- decay searches indicate the need for ton-scale active masses; NEXT-100 provides the springboard to reach this scale with xenon gas. I describe a scenario for performing both searches in a single high-pressure ton-scale xenon gas detector, without significant compromise to either. In addition, -- even in a single, ton-scale, high-pressure xenon gas TPC, an intrinsic sensitivity to the nuclear recoil direction may exist -- plausibly offering an advance of more than two orders of magnitude relative to current low-pressure TPC concepts. I argue that, in an era of deepening fiscal austerity, such a dual-purpose detector may be possible, at acceptable cost, within the time frame of interest, and deserves our collective attention.

  1. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Shear thirning will cause a normally viscous fluid -- such as pie filling or whipped cream -- to deform and flow more readily under high shear conditions. In shear thinning, a pocket of fluid will deform and move one edge forward, as depicted here.

  2. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Shear thirning will cause a normally viscous fluid -- such as pie filling or whipped cream -- to deform and flow more readily under high shear conditions. In shear thinning, a pocket of fluid will deform and move one edge forward, as depicted here.

  3. Simultaneous magnetic resonance imaging of ventilation distribution and gas uptake in the human lung using hyperpolarized xenon-129

    PubMed Central

    Mugler, John P.; Altes, Talissa A.; Ruset, Iulian C.; Dregely, Isabel M.; Mata, Jaime F.; Miller, G. Wilson; Ketel, Stephen; Ketel, Jeffrey; Hersman, F. William; Ruppert, Kai

    2010-01-01

    Despite a myriad of technical advances in medical imaging, as well as the growing need to address the global impact of pulmonary diseases, such as asthma and chronic obstructive pulmonary disease, on health and quality of life, it remains challenging to obtain in vivo regional depiction and quantification of the most basic physiological functions of the lung—gas delivery to the airspaces and gas uptake by the lung parenchyma and blood—in a manner suitable for routine application in humans. We report a method based on MRI of hyperpolarized xenon-129 that permits simultaneous observation of the 3D distributions of ventilation (gas delivery) and gas uptake, as well as quantification of regional gas uptake based on the associated ventilation. Subjects with lung disease showed variations in gas uptake that differed from those in ventilation in many regions, suggesting that gas uptake as measured by this technique reflects such features as underlying pathological alterations of lung tissue or of local blood flow. Furthermore, the ratio of the signal associated with gas uptake to that associated with ventilation was substantially altered in subjects with lung disease compared with healthy subjects. This MRI-based method provides a way to quantify relationships among gas delivery, exchange, and transport, and appears to have significant potential to provide more insight into lung disease. PMID:21098267

  4. The XENON dark matter experiment

    NASA Astrophysics Data System (ADS)

    Aprile, Elena; Xenon Collaboration

    The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xenon nuclei. With a fiducial mass of 1000 kg of liquid xenon, a sufficiently low threshold of 16 keV recoil energy and an un-rejected background rate of 10 events per year, XENON would be sensitive to a WIMP-nucleon interaction cross section of ~10-46cm2, for WIMPs with masses above 50 GeV. The 1 tonne scale experiment (XENON1T) will be realized with an array of ten identical 100 kg detector modules (XENON100). The detectors are time projection chambers operated in dual (liquid/gas) phase, to detect simultaneously the ionization, through secondary scintillation in the gas, and primary scintillation in the liquid produced by low energy recoils. The distinct ratio of primary to secondary scintillation for nuclear recoils from WIMPs (or neutrons), and for electron recoils from background, is key to the event-by-event discrimination capability of XENON. A 3kg dual phase detector with light readout provided by an array of 7 photomultipliers is currently being tested, along with other prototypes dedicated to various measurements relevant to the XENON program. We present some of the results obtained to-date and briefly discuss the next step in the phased approach to the XENON experiment, i.e. the development and underground deployment of a 10 kg detector (XENON10) during 2005.

  5. Noble Gas (Argon and Xenon)-Saturated Cold Storage Solutions Reduce Ischemia-Reperfusion Injury in a Rat Model of Renal Transplantation

    PubMed Central

    Irani, Y.; Pype, J.L.; Martin, A.R.; Chong, C.F.; Daniel, L.; Gaudart, J.; Ibrahim, Z.; Magalon, G.; Lemaire, M.; Hardwigsen, J.

    2011-01-01

    Background Following kidney transplantation, ischemia-reperfusion injury contributes to adverse outcomes. The purpose of this study was to determine whether a cold-storage solution saturated with noble gas (xenon or argon) could limit ischemia-reperfusion injury following cold ischemia. Methods Sixty Wistar rats were randomly allocated to 4 experimental groups. Kidneys were harvested and then stored for 6 h before transplantation in cold-storage solution (Celsior®) saturated with either air, nitrogen, xenon or argon. A syngenic orthotopic transplantation was performed. Renal function was determined on days 7 and 14 after transplantation. Transplanted kidneys were removed on day 14 for histological and immunohistochemical analyses. Results Creatinine clearance was significantly higher and urinary albumin significantly lower in the argon and xenon groups than in the other groups at days 7 and 14. These effects were considerably more pronounced for argon than for xenon. In addition, kidneys stored with argon, and to a lesser extent those stored with xenon, displayed preserved renal architecture as well as higher CD-10 and little active caspase-3 expression compared to other groups. Conclusion Argon- or xenon-satured cold-storage solution preserved renal architecture and function following transplantation by reducing ischemia-reperfusion injury. PMID:22470401

  6. Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

    SciTech Connect

    Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

    2013-10-01

    The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbent development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.

  7. Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

    SciTech Connect

    Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

    2013-09-01

    The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbent development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.

  8. Novel sorbent development and evaluation for the capture of krypton and xenon from nuclear fuel reprocessing off-gas stream

    SciTech Connect

    Garn, T.G.; Greenhalgh, M.R.; Law, J.D.

    2013-07-01

    The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbent development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, Idaho National Laboratory sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up. (authors)

  9. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of liquid xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Resembling a tiny bit of window screen, the oscillator at the heart of CVX-2 will vibrate between two pairs of paddle-like electrodes. The slight bend in the shape of the mesh has no effect on the data. What counts are the mesh's displacement in the xenon fluid and the rate at which the displacement dampens. The unit shown here is encased in a small test cell and capped with a sapphire windown to contain the xenon at high pressure.

  10. Regional Mapping of Gas Uptake by Blood and Tissue in the Human Lung using Hyperpolarized Xenon-129 MRI

    PubMed Central

    Qing, Kun; Ruppert, Kai; Jiang, Yun; Mata, Jaime F.; Miller, G. Wilson; Shim, Y. Michael; Wang, Chengbo; Ruset, Iulian C.; Hersman, F. William; Altes, Talissa A.; Mugler, John P.

    2013-01-01

    Purpose To develop a breath-hold acquisition for regional mapping of ventilation and the fractions of hyperpolarized xenon-129 (Xe129) dissolved in tissue (lung parenchyma and plasma) and red blood cells (RBCs), and to perform an exploratory study to characterize data obtained in human subjects. Materials and Methods A three-dimensional, multi-echo, radial-trajectory pulse sequence was developed to obtain ventilation (gaseous Xe129), tissue and RBC images in healthy subjects, smokers and asthmatics. Signal ratios (total dissolved Xe129 to gas, tissue-to-gas, RBC-to-gas and RBC-to-tissue) were calculated from the images for quantitative comparison. Results Healthy subjects demonstrated generally uniform values within coronal slices, and a gradient in values along the anterior-to-posterior direction. In contrast, images and associated ratio maps in smokers and asthmatics were generally heterogeneous and exhibited values mostly lower than those in healthy subjects. Whole-lung values of total dissolved Xe129 to gas, tissue-to-gas, and RBC-to-gas ratios in healthy subjects were significantly larger than those in diseased subjects. Conclusion Regional maps of tissue and RBC fractions of dissolved Xe129 were obtained from a short breath-hold acquisition, well tolerated by healthy volunteers and subjects with obstructive lung disease. Marked differences were observed in spatial distributions and overall amounts of Xe129 dissolved in tissue and RBCs among healthy subjects, smokers and asthmatics. PMID:23681559

  11. Process for testing a xenon gas feed system of a hollow cathode assembly

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J. (Inventor); Verhey, Timothy R. R. (Inventor); Soulas, George C. (Inventor)

    2004-01-01

    The design and manufacturing processes for Hollow Cathode Assemblies (HCA's) that operate over a broad range of emission currents up to 30 Amperes, at low potentials, with lifetimes in excess of 17,500 hours. The processes include contamination control procedures which cover hollow cathode component cleaning procedures, gas feed system designs and specifications, and hollow cathode activation and operating procedures to thereby produce cathode assemblies that have demonstrated stable and repeatable operating conditions, for both the discharge current and voltage. The HCA of this invention provides lifetimes of greater than 10,000 hours, and expected lifetimes of greater than 17,500 hours, whereas the present state-of-the-art is less than 500 hours at emission currents in excess of 1 Ampere. Stable operation is provided over a large range of operating emission currents, up to a 6:1 ratio, and this HCA can emit electron currents of up to 30 Amperes in magnitude to an external anode that simulates the current drawn to a space plasma, at voltages of less than 20 Volts.

  12. Apparatus and method for monitoring of gas having stable isotopes

    DOEpatents

    Clegg, Samuel M; Fessenden-Rahn, Julianna E

    2013-03-05

    Gas having stable isotopes is monitored continuously by using a system that sends a modulated laser beam to the gas and collects and transmits the light not absorbed by the gas to a detector. Gas from geological storage, or from the atmosphere can be monitored continuously without collecting samples and transporting them to a lab.

  13. Stroke risk after abrupt internal carotid artery sacrifice: Accuracy of preoperative assessment with balloon test occlusion and stable xenon-enhanced CT

    SciTech Connect

    Linskey, M.E.; Jungreis, C.A.; Yonas, H.; Hirsch, W.L. Jr.; Sekhar, L.N.; Horton, J.A.; Janosky, J.E.

    1994-05-01

    To evaluate stable xenon-enhanced CT cerebral blood flow with balloon test occlusion as a predictor of stroke risk in internal carotid artery sacrifice. Abrupt internal carotid artery occlusion was performed by surgical or endovascular means below the origin of the ophthalmic artery in 31 normotensive patients who were assessed preoperatively by a 15-minute clinical balloon test occlusion followed by an internal carotid artery-occluded xenon CT cerebral blood flow study. One patient, who passed the clinical test occlusion but exhibited regions of cerebral blood flow less than 30 mL/100 g per minute on the occlusion xenon CT cerebral blood flow study went on to have a fatal stroke corresponding exactly to the region of assessment. Neuroimaging demonstrated possible flow-related infarctions, which subsequently developed in three patients. Two patients were asymptomatic, and one patient was left with a mild residual hemiparesis. Our protocol provided a statistically significant reduction in subsequent infarction rate and infarction-related death rate when compared with a control group of normotensive abrupt internal carotid artery occlusion patients who did not undergo any preoperative stroke-risk assessment (reported in the literature). The estimated false-negative rate for our preoperative assessment protocol ranged from 3.3% to 10% depending on the assessment of the cause of the three potentially flow-related infarctions. Although life-threatening major vascular territory infarctions have been avoided, our protocol is less sensitive to changes predicting smaller, often minimally symptomatic, vascular border zone infarctions and does not predict postoperative thromboembolic strokes. 94 refs., 5 figs., 4 tabs.

  14. Xenon gas field ion source from a single-atom tip

    NASA Astrophysics Data System (ADS)

    Lai, Wei-Chiao; Lin, Chun-Yueh; Chang, Wei-Tse; Li, Po-Chang; Fu, Tsu-Yi; Chang, Chia-Seng; Tsong, T. T.; Hwang, Ing-Shouh

    2017-06-01

    Focused ion beam (FIB) systems have become powerful diagnostic and modification tools for nanoscience and nanotechnology. Gas field ion sources (GFISs) built from atomic-size emitters offer the highest brightness among all ion sources and thus can improve the spatial resolution of FIB systems. Here we show that the Ir/W(111) single-atom tip (SAT) can emit high-brightness Xe+ ion beams with a high current stability. The ion emission current versus extraction voltage was analyzed from 150 K up to 309 K. The optimal emitter temperature for maximum Xe+ ion emission was ˜150 K and the reduced brightness at the Xe gas pressure of 1 × 10-4 torr is two to three orders of magnitude higher than that of a Ga liquid metal ion source, and four to five orders of magnitude higher than that of a Xe inductively coupled plasma ion source. Most surprisingly, the SAT emitter remained stable even when operated at 309 K. Even though the ion current decreased with increasing temperature, the current at room temperature (RT) could still reach over 1 pA when the gas pressure was higher than 1 × 10-3 torr, indicating the feasibility of RT-Xe-GFIS for application to FIB systems. The operation temperature of Xe-SAT-GFIS is considerably higher than the cryogenic temperature required for the helium ion microscope (HIM), which offers great technical advantages because only simple or no cooling schemes can be adopted. Thus, Xe-GFIS-FIB would be easy to implement and may become a powerful tool for nanoscale milling and secondary ion mass spectroscopy.

  15. Krypton and xenon in Apollo 14 samples - Fission and neutron capture effects in gas-rich samples

    NASA Technical Reports Server (NTRS)

    Drozd, R.; Hohenberg, C.; Morgan, C.

    1975-01-01

    Gas-rich Apollo 14 breccias and trench soil are examined for fission xenon from the decay of the extinct isotopes Pu-244 and I-129, and some samples have been found to have an excess fission component which apparently was incorporated after decay elsewhere and was not produced by in situ decay. Two samples have excess Xe-129 resulting from the decay of I-129. The excess is correlated at low temperatures with excess Xe-128 resulting from neutron capture on I-127. This neutron capture effect is accompanied by related low-temperature excesses of Kr-80 and Kr-82 from neutron capture on the bromine isotopes. Surface correlated concentrations of iodine and bromine are calculated from the neutron capture excesses.

  16. [Xenon: From rare gaz to doping product].

    PubMed

    Tassel, Camille; Le Daré, Brendan; Morel, Isabelle; Gicquel, Thomas

    2016-04-01

    Doping is defined as the use of processes or substances to artificially increase physical or mental performance. Xenon is a noble gas used as an anesthetic and recently as a doping agent. Xenon is neuroprotective as an antagonist of NMDA glutamate receptors. Xenon stimulates the synthesis of erythropoietin (EPO) by increase of hypoxia inducible factor (HIF). Xenon would be a new doping product, maintaining doping methods ahead of detection.

  17. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    SciTech Connect

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A.B.; Nygren, D.

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

  18. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    DOE PAGES

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; ...

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at themore » 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.« less

  19. 2D multinuclear NMR, hyperpolarized xenon and gas storage in organosilica nanochannels with crystalline order in the walls.

    PubMed

    Comotti, Angiolina; Bracco, Silvia; Valsesia, Patrizia; Ferretti, Lisa; Sozzani, Piero

    2007-07-11

    The combination of 2D 1H-13C and 1H-29Si solid state NMR, hyperpolarized 129Xe NMR, synchrotron X-ray diffraction, together with adsorption measurements of vapors and gases for environmental and energetic relevance, was used to investigate the structure and the properties of periodic mesoporous hybrid p-phenylenesilica endowed with crystalline order in the walls. The interplay of 1H, 13C, and 29Si in the 2D heteronuclear correlation NMR measurements, together with the application of Lee-Goldburg homonuclear decoupling, revealed the spatial relationships (<5 angstroms) among various spin-active nuclei of the framework. Indeed, the through-space correlations in the 2D experiments evidenced, for the first time, the interfaces of the matrix walls with guest molecules confined in the nanochannels. Organic-inorganic and organic-organic heterogeneous interfaces between the matrix and the guests were identified. The open-pore structure and the easy accessibility of the nanochannels to the gas phase have been demonstrated by highly sensitive hyperpolarized (HP) xenon NMR, under extreme xenon dilution. Two-dimensional exchange experiments showed the exchange time to be as short as 2 ms. Through variable-temperature HP 129Xe NMR experiments we were able to achieve an unprecedented description of the nanochannel space and surface, a physisorption energy of 13.9 kJ mol-1, and the chemical shift value of xenon probing the internal surfaces. These results prompted us to measure the high storage capacity of the matrix towards benzene, hexafluorobenzene, ethanol, and carbon dioxide. Both host-guest, CH...pi, and OH...pi interactions contribute to the stabilization of the aromatic guests (benzene and hexafluorobenzene) on the extended surfaces. The full carbon dioxide loading in the channels could be detected by synchrotron radiation X-ray diffraction experiments. The selective adsorption of carbon dioxide (ca. 90 wt %) vs that of oxygen and hydrogen, together with the permanent

  20. A Decade of Xenon Chemistry

    ERIC Educational Resources Information Center

    Moody, G. J.

    1974-01-01

    Presents reactions for the formation of xenon compounds and compounds of the other inert gases. Provides bonding and structure theories for noble gas compounds and speculates on possible applications. (GS)

  1. A Decade of Xenon Chemistry

    ERIC Educational Resources Information Center

    Moody, G. J.

    1974-01-01

    Presents reactions for the formation of xenon compounds and compounds of the other inert gases. Provides bonding and structure theories for noble gas compounds and speculates on possible applications. (GS)

  2. Critical Viscosity of Xenon

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2001 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure that is placed inside a pressure canister. A similar canister holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (not shown) of the National Institutes of Standards and Technology, Gaithersburg, MD. This is a detail view of MSFC 0100143.

  3. Optical pumping and xenon NMR

    SciTech Connect

    Raftery, M. Daniel

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  4. Optical pumping and xenon NMR

    SciTech Connect

    Raftery, M.D.

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping [sup 129]Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the [sup 131]Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.

  5. [Xenon light therapy].

    PubMed

    Kanai, Akifumi

    2012-07-01

    The xenon light, generated by high-intensity electrical stimulation of xenon gas, is used to sterilize wounds, aid tissue repair, and relieve pain as a low-level light therapy. The light produced consists of non-coherent beams of multiple wavelengths in the ultraviolet to infrared spectrum. This broad-band light can be emitted in a continuous wave or pulsed mode, with the wave band chosen and the energy distribution controlled for the purpose. Specifically, wavelengths in the 500-700 nm range are suitable for treating superficial tissue, and wavelengths between 800 and 1,000 nm are suitable for deeper-seated tissues, due to longer optical penetration distances through tissue. One of the most common benefits in the xenon light therapy is considered to be the wide and deep irradiation of optimal rays to living tissue. Research into the use of xenon light for tissue repair and pain reduction is restricted within open-label studies and case reports. The present review expounded the effects of xenon light therapy on the basis of the available evidence in vitro and in vivo studies using a laser beam of single wavelength.

  6. Tortuosity measurement and the effects of finite pulse widths on xenon gas diffusion NMR studies of porous media

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Hurlimann, M. D.; Sen, P. N.; Schwartz, L. M.; Patz, S.; Walsworth, R. L.

    2001-01-01

    We have extended the utility of NMR as a technique to probe porous media structure over length scales of approximately 100-2000 microm by using the spin 1/2 noble gas 129Xe imbibed into the system's pore space. Such length scales are much greater than can be probed with NMR diffusion studies of water-saturated porous media. We utilized Pulsed Gradient Spin Echo NMR measurements of the time-dependent diffusion coefficient, D(t), of the xenon gas filling the pore space to study further the measurements of both the pore surface-area-to-volume ratio, S/V(p), and the tortuosity (pore connectivity) of the medium. In uniform-size glass bead packs, we observed D(t) decreasing with increasing t, reaching an observed asymptote of approximately 0.62-0.65D(0), that could be measured over diffusion distances extending over multiple bead diameters. Measurements of D(t)/D(0) at differing gas pressures showed this tortuosity limit was not affected by changing the characteristic diffusion length of the spins during the diffusion encoding gradient pulse. This was not the case at the short time limit, where D(t)/D(0) was noticeably affected by the gas pressure in the sample. Increasing the gas pressure, and hence reducing D(0) and the diffusion during the gradient pulse served to reduce the previously observed deviation of D(t)/D(0) from the S/V(p) relation. The Pade approximation is used to interpolate between the long and short time limits in D(t). While the short time D(t) points lay above the interpolation line in the case of small beads, due to diffusion during the gradient pulse on the order of the pore size, it was also noted that the experimental D(t) data fell below the Pade line in the case of large beads, most likely due to finite size effects.

  7. Quantitative investigation of xenon consumption and recovery during low pressure ac discharges in rare gas mixtures

    NASA Astrophysics Data System (ADS)

    Stafast, H.; Redlich, L.; Linke, H.-P.

    2006-11-01

    Xe gas in low pressure discharge tubes (20 mm diameter, 800 mm length, commercial hollow electrodes at 650 mm distance, 50 Hz, 60 mA) was quantitatively determined using quadrupole mass spectrometry (QMS). The temporal Xe gas evolution over 5 to 20 h of gas discharge revealed the consumption and recovery of Xe gas to be dependent on the prevailing gas composition. The net consumption in the standard Xe/He(2.0/98) gas mixture was much faster than that in Xe/Kr/He(1.9/93/5). Xe recovery during discharges in 'preloaded' tubes refilled with pure gas revealed an increasing efficiency in the sequence He < Ne < Ar < Kr, being most efficient with the first refilling. The temporal evolution of Xe gas was simulated by a kinetic model based on two equilibria between Xe gas and Xe incorporated in the glass tube walls (1) and the electrodes (2). It is concluded that the experimental setup, the elaborated measurement procedures and the kinetic model provide a good basis for further quantitative investigations. The net Xe gas consumption during discharge, which is presently limiting the tube lifetime, may be reduced particularly by improving the discharge gas composition and the electrode materials.

  8. Modeling of a DC glow discharge in a neon-xenon gas mixture at low pressure and with metastable atom densities

    NASA Astrophysics Data System (ADS)

    Bouchikhi, A.

    2017-09-01

    The physical properties of Ne-Xe DC glow discharges at low pressure are reported for a gap length of 1 cm for the first time in the literature. The model deals specifically with the first three moments of Boltzmann’s equation and includes the radiation processes and metastable atom densities. The spatio-temporal distributions of the electron and neon and xenon ion densities, the neon and xenon metastable atom densities, the electric potential and the electric field as well as the mean electron energy are presented at 1.5 Torr and 250 V. The current-voltage characteristic is shown at 3 Torr, and it is compared with previous work for pure neon gas. The model is validated theoretically and experimentally in the case of pure gas.

  9. Production of Samples of Individual Radioxenon Isotopes Through Neutron Irradiation of Stable Xenon Gas

    DTIC Science & Technology

    2008-09-01

    Whitney, S. C. (2006). Light-Element Neutron Depth Profiling at the University of Texas. MS Thesis, University of Texas at Austin. 2008 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies 757

  10. Critical Viscosity of Xenon investigators

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Dr. Dr. Robert F. Berg (right), principal investigator and Dr. Micheal R. Moldover (left), co-investigator, for the Critical Viscosity of Xenon (CVX/CVX-2) experiment. They are with the National Institutes of Standards and Technology, Gaithersburg, MD. The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of chemicals.

  11. First proof of topological signature in the high pressure xenon gas TPC with electroluminescence amplification for the NEXT experiment

    SciTech Connect

    Ferrario, P.

    2016-01-19

    The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure 136Xe gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Qββ. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of 22Na 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the 228Th decay chain were used to represent the background and the signal in a double beta decay. Furthermore, these data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 ± 1.4 (stat.)%, while maintaining an efficiency of 66.7 ± 1% for signal events.

  12. First proof of topological signature in the high pressure xenon gas TPC with electroluminescence amplification for the NEXT experiment

    DOE PAGES

    Ferrario, P.

    2016-01-19

    The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure 136Xe gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Qββ. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of 22Na 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the 228Th decay chain were used tomore » represent the background and the signal in a double beta decay. Furthermore, these data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 ± 1.4 (stat.)%, while maintaining an efficiency of 66.7 ± 1% for signal events.« less

  13. Xenon Additives Detection in Helium Micro-Plasma Gas Analytical Sensor

    NASA Astrophysics Data System (ADS)

    Tsyganov, Alexander; Kudryavtsev, Anatoliy; Mustafaev, Alexander

    2012-10-01

    Electron energy spectra of Xe atoms at He filled micro-plasma afterglow gas analyzer were observed using Collisional Electron Spectroscopy (CES) method [1]. According to CES, diffusion path confinement for characteristic electrons makes it possible to measure electrons energy distribution function (EEDF) at a high (up to atmospheric) gas pressure. Simple geometry micro-plasma CES sensor consists of two plane parallel electrodes detector and microprocessor-based acquisition system providing current-voltage curve measurement in the afterglow of the plasma discharge. Electron energy spectra are deduced as 2-nd derivative of the measured current-voltage curve to select characteristic peaks of the species to be detected. Said derivatives were obtained by the smoothing-differentiating procedure using spline least-squares approximation of a current-voltage curve. Experimental results on CES electron energy spectra at 10-40 Torr in pure He and in admixture with 0.3% Xe are discussed. It demonstrates a prototype of the new miniature micro-plasma sensors for industry, safety and healthcare applications. [1]. A.A.Kudryavtsev, A.B.Tsyganov. US Patent 7,309,992. Gas analysis method and ionization detector for carrying out said method, issued December 18, 2007.

  14. Apparatus complex based on liquid xenon detector for gamma spectrometry in the intervals between pulses of intense radiation

    NASA Astrophysics Data System (ADS)

    Kirsanov, M. A.

    2017-01-01

    To investigate the effects of intense radiation on the operation of the liquid xenon spectrometer we have created apparatus complex on the basis of the liquid xenon detector. The experimental setup consists of a multifunctional chamber, gas system, cooling system, temperature control system, X-ray generator, a special preamp, passive protection, scintillation monitor of the accelerator beam, thermoluminescent dosimeters, copper monitor bremsstrahlung, Ge(Li) detector. Multifunctional chamber includes a detecting unit (flat or cylindrical ionization chamber), the cleaning unit of the xenon, control unit of the purity of liquid xenon. The liquid xenon detector was irradiated by bremsstrahlung pulses of the microtron. The frequency of irradiation pulses was 400 Hz. The absorbed dose was varied from 10-7 to 0.1 Gy per pulse. The electronic and ionic processes in liquid xenon at different radiation doses were investigated. The recovery time of the spectrometric mode of operation of the liquid xenon detector after intense pulse irradiation has been studied. Stable operation of the liquid xenon spectrometer in the intervals between the pulses of the accelerator shown for a long time.

  15. Generation of radio frequency induced metastable xenon as a gain medium for diode pumped rare gas laser systems

    NASA Astrophysics Data System (ADS)

    Andreozzi, Jacqueline Marie

    The pursuit of novel, hybrid methods of achieving lasing from the rare gases has recently been a topic of interest in the field of high energy laser systems. This investigation presents the construction and execution of an experimental setup designed to generate metastable xenon (Xe*) to determine its potential to perform as a high power laser gain medium in a similar capacity as the alkali metals in Diode Pumped Alkali Lasers. A capacitively coupled radio frequency discharge was used to light plasma from naturally abundant xenon, thus exciting the 6s[3/2]2 metastable state. The metastable xenon was probed with a tunable diode laser at 882.2 and 904.8 nanometers, and absorption was detected to verify the presence of Xe* atoms. The absorption profiles are reported with in-depth calculations of the isotope shift and hyperfine structure of each absorption line. Preliminary calculations for the properties of the proposed laser system are also presented.

  16. Application of Two Phase (Liquid/Gas) Xenon Gamma-Camera for the Detection of Special Nuclear Material and PET Medical Imaging

    SciTech Connect

    McKinsey, Daniel Nicholas

    2013-08-27

    The McKinsey group at Yale has been awarded a grant from DTRA for the building of a Liquid Xenon Gamma Ray Color Camera (LXe-GRCC), which combines state-of-the-art detection of LXe scintillation light and time projection chamber (TPC) charge readout. The DTRA application requires a movable detector and hence only a single phase (liquid) xenon detector can be considered in this case. We propose to extend the DTRA project to applications that allow a two phase (liquid/gas) xenon TPC. This entails additional (yet minimal) hardware and extension of the research effort funded by DTRA. The two phase detector will have better energy and angular resolution. Such detectors will be useful for PET medical imaging and detection of special nuclear material in stationary applications (e.g. port of entry). The expertise of the UConn group in gas phase TPCs will enhance the capabilities of the Yale group and the synergy between the two groups will be very beneficial for this research project as well as the education and research projects of the two universities. The LXe technology to be used in this project has matured rapidly over the past few years, developed for use in detectors for nuclear physics and astrophysics. This technology may now be applied in a straightforward way to the imaging of gamma rays. According to detailed Monte Carlo simulations recently performed at Yale University, energy resolution of 1% and angular resolution of 3 degrees may be obtained for 1.0 MeV gamma rays, using existing technology. With further research and development, energy resolution of 0.5% and angular resolution of 1.3 degrees will be possible at 1.0 MeV. Because liquid xenon is a high density, high Z material, it is highly efficient for scattering and capturing gamma rays. In addition, this technology scales elegantly to large detector areas, with several square meter apertures possible. The Yale research group is highly experienced in the development and use of noble liquid detectors for

  17. LASER APPLICATIONS AND OTHER TOPICS IN LASER TECHNOLOGY: Xenon and hydrogen gas mixtures as laser active media

    NASA Astrophysics Data System (ADS)

    Zuev, V. S.; Kanaev, A. V.; Mikheev, L. D.

    1988-08-01

    It is suggested that gaseous mixtures of xenon and molecular hydrogen may be used as active media of Xe2 (172 nm) and XeH ( ~ 250 nm) photochemical lasers. By adding more than 3 Torr of hydrogen to xenon, amplification can be achieved in the 172 nm range as a result of quenching of the 1u/0u- absorbing state under optical pumping conditions. The hydrogen atoms produced by the quenching process can be utilized to populate XeH* by three-body recombination with Xe* ( 3P1/2) atoms.

  18. Barium Tagging for nEXO in Liquid and Gas Xenon

    NASA Astrophysics Data System (ADS)

    Kravitz, Scott; Brunner, Thomas; Fudenberg, Dan; nEXO Collaboration

    2015-04-01

    nEXO is a next-generation multi-ton experiment currently under development to search for neutrinoless double-beta decay of Xe-136. A positive observation will determine the neutrino to be a Majorana particle. In order to greatly reduce backgrounds for this search, the nEXO collaboration is developing several techniques to recover and identify the decay daughter, Ba-136 (``barium tagging''). This technique may be available for a second phase of the nEXO detector and will improve the sensitivity to probe the neutrino mass scale beyond the inverted hierarchy. A setup to demonstrate Ba ion capture on a probe and subsequent identification through resonance ionization spectroscopy has been developed, and is being used to investigate possible probe substrates, including graphene. For a gas phase detector, appropriate for a later stage, a separate apparatus to extract Ba ions using an RF-only funnel has been constructed and demonstrates extraction of ions from high-pressure Xe to vacuum consistent with simulations. We will describe the status of these systems and the present results of this R&D program.

  19. XENON: A Search for Dark Matter Particles in Liquid Xenon

    NASA Astrophysics Data System (ADS)

    Aprile, Elena; Giboni, Karl-Ludwig; Majewski, Pawel; Ni, Kaixuan; Singh, Bhartendu; Yamashita, Masaki; Gaitskell, Richard; Deviveiros, Luiz; Sorensen, Peter; Shutt, Tom; John, Kwong; McKinsey, Daniel; Hasty, Richard; Oberlack, Uwe; Omar, Vargas

    2004-05-01

    The XENON experiment has been proposed to search for dark matter Weakly Interacting Massive Particles (WIMPs) through their interactions in 1-tonne of liquid xenon, distributed in an array of time projection chambers (TPCs). The sensitivity goal for 3 years operation underground is s ˜ 10-46 cm2 , about a factor 100 beyond that projected for current cryogenic experiments such as CDMS and EDELWEISS. This is achieved through a combination of large active target, low threshold ( ˜16 keV recoil energy) with dual phase (liquid/gas) operation, and high background discrimination (>99.5%) with the simultaneous detection of ionization and scintillation signals produced in pure liquid xenon by a WIMP recoil. Event localization in 3-D and the use of a liquid xenon self-shielding veto give additional discrimination power. We present the status of the XENON R program and the design and expected performance of the first experiment module, called XENON-100, operating in a suitable underground laboratory.

  20. Magnetic resonance imaging of convection in laser-polarized xenon

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Tseng, C. H.; Wong, G. P.; Cory, D. G.; Walsworth, R. L.

    2000-01-01

    We demonstrate nuclear magnetic resonance (NMR) imaging of the flow and diffusion of laser-polarized xenon (129Xe) gas undergoing convection above evaporating laser-polarized liquid xenon. The large xenon NMR signal provided by the laser-polarization technique allows more rapid imaging than one can achieve with thermally polarized gas-liquid systems, permitting shorter time-scale events such as rapid gas flow and gas-liquid dynamics to be observed. Two-dimensional velocity-encoded imaging shows convective gas flow above the evaporating liquid xenon, and also permits the measurement of enhanced gas diffusion near regions of large velocity variation.

  1. Magnetic resonance imaging of convection in laser-polarized xenon

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Tseng, C. H.; Wong, G. P.; Cory, D. G.; Walsworth, R. L.

    2000-01-01

    We demonstrate nuclear magnetic resonance (NMR) imaging of the flow and diffusion of laser-polarized xenon (129Xe) gas undergoing convection above evaporating laser-polarized liquid xenon. The large xenon NMR signal provided by the laser-polarization technique allows more rapid imaging than one can achieve with thermally polarized gas-liquid systems, permitting shorter time-scale events such as rapid gas flow and gas-liquid dynamics to be observed. Two-dimensional velocity-encoded imaging shows convective gas flow above the evaporating liquid xenon, and also permits the measurement of enhanced gas diffusion near regions of large velocity variation.

  2. Stability of xenon oxides at high pressures.

    PubMed

    Zhu, Qiang; Jung, Daniel Y; Oganov, Artem R; Glass, Colin W; Gatti, Carlo; Lyakhov, Andriy O

    2013-01-01

    Xenon, which is quite inert under ambient conditions, may become reactive under pressure. The possibility of the formation of stable xenon oxides and silicates in the interior of the Earth could explain the atmospheric missing xenon paradox. Using an ab initio evolutionary algorithm, we predict the existence of thermodynamically stable Xe-O compounds at high pressures (XeO, XeO(2) and XeO(3) become stable at pressures above 83, 102 and 114 GPa, respectively). Our calculations indicate large charge transfer in these oxides, suggesting that large electronegativity difference and high pressure are the key factors favouring the formation of xenon compounds. However, xenon compounds cannot exist in the Earth's mantle: xenon oxides are unstable in equilibrium with the metallic iron occurring in the lower mantle, and xenon silicates are predicted to decompose spontaneously at all mantle pressures (<136 GPa). However, it is possible that xenon atoms may be retained at defects in mantle silicates and oxides.

  3. Analgesic Effect of Xenon in Rat Model of Inflammatory Pain.

    PubMed

    Kukushkin, M L; Igon'kina, S I; Potapov, S V; Potapov, A V

    2017-02-01

    The analgesic effects of inert gas xenon were examined on rats. The formalin model of inflammatory pain, tail-flick test, and hot-plate test revealed the antinociceptive effects of subanesthetizing doses of inhalation anesthetic xenon. Inhalation of 50/50 xenon/oxygen mixture moderated the nociceptive responses during acute and tonic phases of inflammatory pain.

  4. Solid Xenon Project

    SciTech Connect

    Balakishiyeva, Durdana N.; Saab, Tarek; Mahapatra, Rupak; Yoo, Jonghee

    2010-08-30

    Crystals like Germanium and Silicon need to be grown in specialized facilities which is time and money costly. It takes many runs to test the detector once it's manufactured and mishaps are very probable. It is of a great challenge to grow big germanium crystals and that's why stacking them up in a tower is the only way at the moment to increase testing mass. Liquid Noble gas experiments experiencing contamination problems, their predicted energy resolution at 10 keV and lower energy range is not as good as predicted. Every experiment is targeting one specific purpose, looking for one thing. Why not to design an experiment that is diverse and build a detector that can search for Dark Matter, Solar Axions, Neutrinoless Double Beta decay, etc. Solid Xenon detector is such detector. We designed a simple Xenon crystal growing chamber that was put together at Fermi National Accelerator Laboratory. The first phase of this experiment was to demonstrate that a good, crack free Xenon crystal can be grown (regardless of many failed attempts by various groups) and our first goal, 1 kg crystal, was successful.

  5. Solid Xenon Project

    NASA Astrophysics Data System (ADS)

    Balakishiyeva, Durdana N.; Mahapatra, Rupak; Saab, Tarek; Yoo, Jonghee

    2010-08-01

    Crystals like Germanium and Silicon need to be grown in specialized facilities which is time and money costly. It takes many runs to test the detector once it's manufactured and mishaps are very probable. It is of a great challenge to grow big germanium crystals and that's why stacking them up in a tower is the only way at the moment to increase testing mass. Liquid Noble gas experiments experiencing contamination problems, their predicted energy resolution at 10 keV and lower energy range is not as good as predicted. Every experiment is targeting one specific purpose, looking for one thing. Why not to design an experiment that is diverse and build a detector that can search for Dark Matter, Solar Axions, Neutrinoless Double Beta decay, etc. Solid Xenon detector is such detector. We designed a simple Xenon crystal growing chamber that was put together at Fermi National Accelerator Laboratory. The first phase of this experiment was to demonstrate that a good, crack free Xenon crystal can be grown (regardless of many failed attempts by various groups) and our first goal, 1 kg crystal, was successful.

  6. A study of the xenon effect in type-II clathrate hydrate synthesis; Commencing with hydrogen, argon and xenon uptake into a propane clathrate hydrate

    NASA Astrophysics Data System (ADS)

    Abbondondola, Joanne Angela

    It has been proposed that clathrate hydrates can be a possible storage medium for alternative fuels, such as hydrogen. The type-II propane gas hydrate is a viable choice because there are twice as many small cages as large cages and the small cavities are available for hydrogen storage. However, propane hydrate formation is a kinetically slow process which makes it commercially unattractive. Our objectives were twofold; (1) to quantify hydrogen, argon and xenon sorption into a preformed type-II propane hydrate at near-ambient conditions and (2) to investigate the effect of xenon on the rate of type-II propane hydrate formation. The propane hydrate is synthesized from 250 mum ice grains, and is estimated to have a porosity of 65 %. Hydrogen is rapidly absorbed by the hydrate sample and approaches the equilibrium vapor pressure in an hour before a very slow residual absorption process ensues. For an initial hydrogen pressure of 1.5 MPa, about 4.5 % of the available 512 cages are occupied by hydrogen after one hour, and 4.9 % after 18 hours. In contrast, for both argon and xenon significantly more gas is absorbed by the hydrate, but at a much slower rate: about 5% as fast for xenon and 1% as fast for argon. We conclude that hydrogen readily diffuses through the propane hydrate microcrystal structure, while argon and xenon are probably absorbed by growing new double hydrate while consuming the propane hydrate. Thus, although considerably higher pressures would be required to store significant quantities of hydrogen in propane hydrate, it appears that the crystal can be loaded and emptied in relatively short amounts of time. Experimental results show that propane is incorporated into clathrate hydrate cages more rapidly using propane-xenon mixtures than for pure propane gas. For a 0.92 xenon: propane mix, 60% of the theoretical yield of propane enclathration is achieved in 20 minutes, versus several days for pure propane. It appears that xenon serves to nucleate the

  7. Xenon Fractionation and Archean Hydrogen Escape

    NASA Technical Reports Server (NTRS)

    Zahnle, K. J.

    2015-01-01

    Xenon is the heaviest gas found in significant quantities in natural planetary atmospheres. It would seem the least likely to escape. Yet there is more evidence for xenon escape from Earth than for any element other than helium and perhaps neon. The most straightforward evidence is that most of the radiogenic Xe from the decay of (129)I (half-life 15.7 Myr) and (244)Pu (half-life 81 Myr) that is Earth's birthright is missing. The missing xenon is often attributed to the impact erosion of early atmospheres of Earth and its ancestors. It is obvious that if most of the radiogenic xenon were driven off by impacts, most of the rest of the atmophiles fared the same fate. The other line of evidence is in the nonradiogenic isotopes of xenon and its silent partner, krypton. Atmospheric xenon is strongly mass fractionated (at about 4% per amu) compared to any known solar system source (Figure 1). This is in stark contrast to krypton, which may not be fractionated at all: atmospheric Kr is slightly heavier than solar Kr (at about 0.5% per amu), but it is the same as in carbonaceous chondrites. Nonradiogenic xenon is also under abundant relative to krypton (the so-called "missing xenon" problem). Together these observations imply that xenon has been subject to fractionating escape and krypton not.

  8. Aerobic fitness in patients with fibrositis. A controlled study of respiratory gas exchange and 133-xenon clearance from exercising muscle

    SciTech Connect

    Bennett, R.M.; Clark, S.R.; Goldberg, L.; Nelson, D.; Bonafede, R.P.; Porter, J.; Specht, D.

    1989-04-01

    Aerobic fitness was evaluated in 25 women with fibrositis, by having them exercise to volitional exhaustion on an electronically braked cycle ergometer. Compared with published standards, greater than 80% of the fibrositis patients were not physically fit, as assessed by maximal oxygen uptake. Compared with matched sedentary controls, fibrositis patients accurately perceived their level of exertion in relation to oxygen consumption and attained a similar level of lactic acidosis, as assessed by their respiratory quotient and ventilatory threshold. Exercising muscle blood flow was estimated by 133-xenon clearance in a subgroup of 16 fibrositis patients and compared with that in 16 matched sedentary controls; the fibrositis patients exhibited reduced 133-xenon clearance. These results indicate a need to include aerobic fitness as a matched variable in future controlled studies of fibrositis and suggest that the detraining phenomenon may be of relevance to the etiopathogenesis of the disease.

  9. Pinning and gas oversaturation imply stable single surface nanobubbles

    NASA Astrophysics Data System (ADS)

    Lohse, Detlef; Zhang, Xuehua

    2015-03-01

    Surface nanobubbles are experimentally known to survive for days at hydrophobic surfaces immersed in gas-oversaturated water. This is different from bulk nanobubbles, which are pressed out by the Laplace pressure against any gas oversaturation and dissolve in submilliseconds, as derived by Epstein and Plesset [J. Chem. Phys. 18, 1505 (1950), 10.1063/1.1747520]. Pinning of the contact line has been speculated to be the reason for the stability of the surface nanobubbles. Building on an exact result by Popov [Phys. Rev. E 71, 036313 (2005), 10.1103/PhysRevE.71.036313] on coffee stain evaporation, here we confirm this speculation by an exact calculation for single surface nanobubbles. It is based only on (i) the diffusion equation, (ii) Laplace pressure, and (iii) Henry's equation, i.e., fluid dynamical equations which are all known to be valid down to the nanometer scale. The crucial parameter is the gas oversaturation ζ of the liquid. At the stable equilibrium, the gas overpressures due to this oversaturation and the Laplace pressure balance. The theory predicts how the contact angle of the pinned bubble depends on ζ and the surface nanobubble's footprint lateral extension L . It also predicts an upper lateral extension threshold for stable surface nanobubbles to exist.

  10. Liquid xenon excimer laser

    SciTech Connect

    Molchanov, Alexander G

    2003-01-31

    The characteristics of the first excimer laser and the history of its creation are presented. The threshold lasing conditions and the modern theory of active media are considered, and the prospects for the development of excimer lasers operating on condensed inert gases are discussed. It is shown that in experiments on pumping liquid xenon, lasing was obtained simultaneously on excimers of several types, including excimers in liquid and gas phases. (special issue devoted to the 80th anniversary of academician n g basov's birth)

  11. Anticonvulsant effect of xenon on neonatal asphyxial seizures.

    PubMed

    Azzopardi, Denis; Robertson, Nicola J; Kapetanakis, Andrew; Griffiths, James; Rennie, Janet M; Mathieson, Sean R; Edwards, A David

    2013-09-01

    Xenon, a monoatomic gas with very high tissue solubility, is a non-competitive inhibitor of N-methyl-D-aspartate (NMDA) glutamate receptor, has antiapoptotic effects and is neuroprotective following hypoxic ischaemic injury in animals. Xenon may be expected to have anticonvulsant effects through glutamate receptor blockade, but this has not previously been demonstrated clinically. We examined seizure activity on the real time and amplitude integrated EEG records of 14 full-term infants with perinatal asphyxial encephalopathy treated within 12 h of birth with 30% inhaled xenon for 24 h combined with 72 h of moderate systemic hypothermia. Seizures were identified on 5 of 14 infants. Seizures stopped during xenon therapy but recurred within a few minutes of withdrawing xenon and stopped again after xenon was restarted. Our data show that subanaesthetic levels of xenon may have an anticonvulsant effect. Inhaled xenon may be a valuable new therapy in this hard-to-treat population.

  12. Critical Viscosity of Xenon team

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure (at left) that is placed inside a pressure canister. A similar canister (right) holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (left) of the National Institutes of Standards and Technology, Gaithersburg, MD.

  13. Critical Viscosity of Xenon team

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure (at left) that is placed inside a pressure canister. A similar canister (right) holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (left) of the National Institutes of Standards and Technology, Gaithersburg, MD.

  14. Critical Viscosity of Xenon team

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure (at left) that is placed inside a pressure canister. A similar canister (right) holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (not shown) of the National Institutes of Standards and Technology, Gaithersburg, MD.

  15. [Effect of inert gas xenon on the functional state of nucleated cells of peripheral blood during freezing].

    PubMed

    Laptev, D S; Polezhaeva, T V; Zaitseva, O O; Khudyakov, A N; Utemov, S V; Knyazev, M G; Kostyaev, A A

    2015-01-01

    A new method of preservation of nucleated cells in the electric refrigerator with xenon. After slow freezing and storage is even one day at -80 °C persists for more than 60% leukocytes. Cell membranes are resistant to the vital dye. In 85% of granulocytes stored baseline lysosomal-cationic protein, reduced lipid peroxidation and antioxidant activity. Cryopreservation of biological objects in inert gases is a promising direction in the practice of medicine and can be an alternative to the traditional method using liquid nitrogen.

  16. Energy Resolution in High Pressure Xenon Gas Using Electroluminescence in Parallel Wire Grids vs. Crossed Wire Meshes

    NASA Astrophysics Data System (ADS)

    Sofka, Clement; White, James

    2013-04-01

    Several rare event searches (e.g. detection of dark matter particles and neutrinoless double beta decay) are ongoing around the globe utilizing electroluminescent (EL) light collection from noble elements in drift chambers. These detectors use various wire geometries to achieve an EL gap that is optimized for light production, light collection, and energy resolution. We investigate the energy resolution of a parallel wire geometry and compare it to an EL gap composed of two crossed meshes in a high pressure gaseous xenon (GXe) drift chamber. The design, construction and results will be discussed.

  17. A stable argon compound

    PubMed

    Khriachtchev; Pettersson; Runeberg; Lundell; Rasanen

    2000-08-24

    The noble gases have a particularly stable electronic configuration, comprising fully filled s and p valence orbitals. This makes these elements relatively non-reactive, and they exist at room temperature as monatomic gases. Pauling predicted in 1933 that the heavier noble gases, whose valence electrons are screened by core electrons and thus less strongly bound, could form stable molecules. This prediction was verified in 1962 by the preparation of xenon hexafluoroplatinate, XePtF6, the first compound to contain a noble-gas atom. Since then, a range of different compounds containing radon, xenon and krypton have been theoretically anticipated and prepared. Although the lighter noble gases neon, helium and argon are also expected to be reactive under suitable conditions, they remain the last three long-lived elements of the periodic table for which no stable compound is known. Here we report that the photolysis of hydrogen fluoride in a solid argon matrix leads to the formation of argon fluorohydride (HArF), which we have identified by probing the shift in the position of vibrational bands on isotopic substitution using infrared spectroscopy. Extensive ab initio calculations indicate that HArF is intrinsically stable, owing to significant ionic and covalent contributions to its bonding, thus confirming computational predictions that argon should form a stable hydride species with properties similar to those of the analogous xenon and krypton compounds reported before.

  18. The origin of the β Pictoris stable gas

    NASA Astrophysics Data System (ADS)

    Lagrange, Anne-Marie; Maddison, Sarah; Augereau, Jean-Charles; Freudling, Wolfram; Lecavelier des Etangs, Alain; Dent, Bill

    2013-10-01

    The disk around the young star β Pictoris is the prototype of debris disks, whereby giant planets have already formed and terrestrial planet building is likely well underway. Multi-wavelength observations from optical to radio provide a detailed view of the dust component of the disk, but the gaseous component remains a mystery. Transient, highly redshifted absorptions lines are known to result from infalling cometary bodies, which may be perturbed by the giant planet we recently discovered orbiting 9 AU from the star. The most puzzling property of the β Pic system, however, is the origin of the stable gas present around the star. Initially seen only in absorption lines of ions and few neutrals, recent observations show emission of neutrals and CO. Our previous attempt to detect 21cm emission with ATCA (Freudling et al., 1995) provided an upper limit on the total HI mass, which has been widely used to constrain models of the gas evolution around β Pic. Our knowledge of the dust and gas disk has significantly evolved in recent years. Given ATCA's improved sensitivity, angular and spectral resolutions compared to our previous observations, we have a unique opportunity to detect HI and obtain information about its location within the disk. This will allow us, for the first time, to fully test if the icy grain scenario is responsible for the CO gas. We anticipate that our observations will have a major impact on the understanding of the β Pic system.

  19. Xenon: anesthesia for the 21st century.

    PubMed

    Joyce, J A

    2000-06-01

    Xenon is a naturally occurring, gaseous element that comprises 0.000008% of air, or 0.05 parts per million. It was discovered by Ramsey and Travers in 1898. Xenon is found on the Periodic Table in group 0, which is the group commonly referred to as the noble or inert gases. It is obtained by fractionally distilling liquefied air. Xenon has been studied sporadically within the discipline of anesthesia as a replacement for nitrous oxide. Because it is a naturally occurring element, xenon is not a pollutant. It is not an occupationally hazardous gas. It is neither teratogenic nor fetotoxic, as is nitrous oxide; it does not contribute to the depletion of stratospheric ozone, as do chlorofluorocarbons and nitrous oxide. Xenon does not contribute to global warming and the greenhouse effect, as does nitrous oxide. Xenon provides excellent anesthesia and analgesia at its minimum alveolar concentration, 71%, as well as excellent analgesia at "subanesthetic" concentrations. Xenon also provides excellent cardiovascular and hemodynamic stability and offers both rapid induction and emergence. Because of the relatively high cost of xenon, a low-flow, closed-system technique is needed to be most cost effective.

  20. Preliminary performance of a 4.97-inch radial turbine operating in a Brayton power system with a helium-xenon gas mixture

    NASA Technical Reports Server (NTRS)

    Leroy, M. J., Jr.; Ream, L. W.; Curreri, J. S.

    1971-01-01

    The performance characteristics of the Brayton-rotating-unit's 4.97-inch radial turbine were investigated with the turbine part of a power conversion system. The following system parameters were varied: turbine inlet temperature from 1200 to 1600 F, compressor inlet temperature from 60 to 120 F, compressor outlet pressure from 20 to 45 psia, and shaft speed from 90-110 percent of rated speed (36000 rpm). The working fluid of the system was a gas mixture of helium-xenon with a nominal molecular weight of 83.8. Test results indicate that changes in system conditions have little effect on the turbine efficiency. At the design turbine inlet temperature of 1600 F and compressor inlet temperature of 80 F, an average turbine efficiency of 91 percent was obtained.

  1. Xenon Feed System Progress

    DTIC Science & Technology

    2006-01-01

    From - To) 13-06-2006 Technical Paper 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER F04611-00-C-0055 Xenon Feed System Progress (Preprint) 5b. GRANT...propulsion xenon feed system for a flight technology demonstration program. Major accomplishments include: 1) Utilization of the Moog...successfully fed xenon to a 200 watt Hall Effect Thruster in a Technology Demonstration Program. The feed system has demonstrated throttling of xenon

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    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 158 and 180 nm wavelength are reported.

  3. Perovskites with the Framework-Forming Xenon.

    PubMed

    Britvin, Sergey N; Kashtanov, Sergei A; Krzhizhanovskaya, Maria G; Gurinov, Andrey A; Glumov, Oleg V; Strekopytov, Stanislav; Kretser, Yury L; Zaitsev, Anatoly N; Chukanov, Nikita V; Krivovichev, Sergey V

    2015-11-23

    The Group 18 elements (noble gases) were the last ones in the periodic system to have not been encountered in perovskite structures. We herein report the synthesis of a new group of double perovskites KM(XeNaO6) (M = Ca, Sr, Ba) containing framework-forming xenon. The structures of the new compounds, like other double perovskites, are built up of the alternating sequence of corner-sharing (XeO6) and (NaO6) octahedra arranged in a three-dimensional rocksalt order. The fact that xenon can be incorporated into the perovskite structure provides new insights into the problem of Xe depletion in the atmosphere. Since octahedrally coordinated Xe(VIII) and Si(IV) exhibit close values of ionic radii (0.48 and 0.40 Å, respectively), one could assume that Xe(VIII) can be incorporated into hyperbaric frameworks such as MgSiO3 perovskite. The ability of Xe to form stable inorganic frameworks can further extend the rich and still enigmatic chemistry of this noble gas.

  4. Venus, Earth, Xenon

    NASA Astrophysics Data System (ADS)

    Zahnle, K. J.

    2013-12-01

    Xenon has been regarded as an important goal of many proposed missions to Venus. This talk is intended to explain why. Despite its being the heaviest gas found in natural planetary atmospheres, there is more evidence that Xe escaped from Earth than for any element apart from helium: (i) Atmospheric Xe is very strongly mass fractionated (at about 4% per amu) from any known solar system source. This suggests fractionating escape that preferentially left the heavy Xe isotopes behind. (ii) Xe is underabundant compared to Kr, a lighter noble gas that is not strongly mass fractionated in air. (iii) Radiogenic Xe is strongly depleted by factors of several to ~100 compared to the quantities expected from radioactive decay of primordial solar system materials. In these respects Xe on Mars is similar to Xe on Earth, but with one key difference: Xe on Mars is readily explained by a simple process like hydrodynamic escape that acts on an initially solar or meteoritic Xe. This is not so for Earth. Earth's Xe cannot be derived by an uncontrived mass fractionating process acting on any known type of Solar System Xe. Earth is a stranger, made from different stuff than any known meteorite or Mars or even the Sun. Who else is in Earth's family? Comets? We know nothing. Father Zeus? Data from Jupiter are good enough to show that jovian Xe is not strongly mass-fractionated but not good enough to determine whether Jupiter resembles the Earth or the Sun. Sister Venus? Noble gas data from Venus are incomplete, with Kr uncertain and Xe unmeasured. Krypton was measured by several instruments on several spacecraft. The reported Kr abundances are discrepant and were once highly controversial. These discrepancies appear to have been not so much resolved as forgotten. Xenon was not detected on Venus. Upper limits were reported for the two most abundant xenon isotopes 129Xe and 132Xe. From the limited data it is not possible to tell whether Venus's affinities lie with the solar wind, or with

  5. Derivation of stable Burnett equations for rarefied gas flows

    NASA Astrophysics Data System (ADS)

    Singh, Narendra; Jadhav, Ravi Sudam; Agrawal, Amit

    2017-07-01

    A set of constitutive relations for the stress tensor and heat flux vector for the hydrodynamic description of rarefied gas flows is derived in this work. A phase density function consistent with Onsager's reciprocity principle and H theorem is utilized to capture nonequilibrium thermodynamics effects. The phase density function satisfies the linearized Boltzmann equation and the collision invariance property. Our formulation provides the correct value of the Prandtl number as it involves two different relaxation times for momentum and energy transport by diffusion. Generalized three-dimensional constitutive equations for different kinds of molecules are derived using the phase density function. The derived constitutive equations involve cross single derivatives of field variables such as temperature and velocity, with no higher-order derivative in higher-order terms. This is remarkable feature of the equations as the number of boundary conditions required is the same as needed for conventional Navier-Stokes equations. Linear stability analysis of the equations is performed, which shows that the derived equations are unconditionally stable. A comparison of the derived equations with existing Burnett-type equations is presented and salient features of our equations are outlined. The classic internal flow problem, force-driven compressible plane Poiseuille flow, is chosen to verify the stable Burnett equations and the results for equilibrium variables are presented.

  6. In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.; Owen, T.; Pavlov, A. A.; Wiens, R. C.; Wong, M. H.; Mahaffy, P. R.

    2016-11-01

    Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

  7. Structures of xenon oxides at high pressures

    NASA Astrophysics Data System (ADS)

    Worth, Nicholas; Pickard, Chris; Needs, Richard; Dewaele, Agnes; Loubeyre, Paul; Mezouar, Mohamed

    2014-03-01

    For many years, it was believed that noble gases such as xenon were entirely inert. It was only in 1962 that Bartlett first synthesized a compound of xenon. Since then, a number of other xenon compounds, including oxides, have been synthesized. Xenon oxides are unstable under ambient conditions but have been predicted to stabilize under high pressure. Here we present the results of a combined theoretical and experimental study of xenon oxides at pressures of 80-100 GPa. We have synthesized new xenon oxides at these pressures and they have been characterized with X-ray diffraction and Raman spectroscopy. Calculations were performed with a density-functional theory framework. We have used the ab-initio random structure searching (AIRSS) method together with a data-mining technique to determine the stable compounds in the xenon-oxygen system in this pressure range. We have calculated structural and optical properties of these phases, and a good match between theoretical and experimental results has been obtained. Funding for computational research provided by the engineering and physical sciences research council (EPSRC; UK). Computing resources provided by Cambridge HPC and HECToR. X-ray diffraction experiments performed at ESRF.

  8. Status and Plans for the XENON Dark Matter Experiment

    NASA Astrophysics Data System (ADS)

    Gaitskell, R. J.; Collaborotion, Xenon

    2005-04-01

    The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xenon nuclei. With a fiducial mass of 1000 kg of liquid xenon, a sufficiently low threshold of 16 keV recoil energy and an un-rejected background rate of 10 events per year, XENON would be sensitive to a WIMP-nucleon interaction cross section of ~ 10-46cm2, for WIMPs with masses above 50 GeV. A 1 tonne scale experiment (XENON1T) would be realized with an array of ten identical 100 kg detector modules (XENON100). The detectors are time projection chambers operated in dual (liquid/gas) phase, to detect simultaneously the ionization, through secondary scintillation in the gas, and primary scintillation in the liquid produced by low energy recoils. The distinct ratio of primary to secondary scintillation for nuclear recoils from WIMPs (or neutrons), and for electron recoils from background, is key to the event-by-event discrimination capability of XENON. A 3kg dual phase detector with light readout provided by an array of 7 photomultipliers is currently being tested, along with other prototypes dedicated to various measurements relevant to the XENON program. We present some of the results obtained to-date and briefly discuss the next step in the phased approach to the XENON experiment, i.e. the development and underground deployment of a 10 kg detector (XENON10) during 2005.

  9. Xenon adsorption in NaA zeolite cavities

    NASA Astrophysics Data System (ADS)

    McCormick, A. V.; Chmelka, B. F.

    Adsorption of xenon atoms in the α-cages of NaA zeolite has been studied using 129Xe NMR spectroscopy to probe directly the distribution and configuration of molecules in confined, microporous environments. The 129Xe NMR spectrum is sensitive to subtle changes in xenon environment, so relative populations of α-cages containing different numbers of xenon guests can be determined and the effects of other co-adsorbed species monitored. On the basis of 129Xe NMR spectra, the distribution of xenon atoms among NaA α-cages is shown to exhibit a marked dependence on the pressure at which the xenon guests are introduced. 129Xe NMR spectra recorded at 200 K reveal that xenon atoms in the NaA α-cages experience diminished mobility (resembling condensation phenomena) at higher temperatures than in the bulk gas of equivalent density. Thus, the chemical potential of adsorbed xenon can be investigated experimentally as a function of both temperature and guest density. The density dependence of the 129Xe chemical shift in Xe/NaA and in bulk xenon gas shows that Xe-Xe interactions in the proximity of the NaA cage wall are important in α-cages containing more than five xenon guests. This trend is linked to entropic effects which may enhance xenon adsorption in the confined environment of the NaA α-cages.

  10. Xenon Blocks Neuronal Injury Associated with Decompression

    PubMed Central

    Blatteau, Jean-Eric; David, Hélène N.; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H.

    2015-01-01

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS. PMID:26469983

  11. Xenon Blocks Neuronal Injury Associated with Decompression.

    PubMed

    Blatteau, Jean-Eric; David, Hélène N; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H

    2015-10-15

    Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS.

  12. Xenon in carbonaceous chondrites.

    NASA Technical Reports Server (NTRS)

    Manuel, O. K.; Hennecke, E. W.; Sabu, D. D.

    1972-01-01

    A table showing the relative amounts of xenon isotopes in carbonaceous chondrites is presented. It is found that the enrichment of heavy xenon isotopes released from carbonaceous chondrites in the approximate temperature range from 600 to 1000 C is accompanied by an enrichment of the light xenon isotopes. The high degree of correlation between these two isotopic anomalies suggests that both result from a common source. There is no known nuclear or physical process which could produce both anomalies in situ. It is, therefore, suggested that the anomalies are the result of the release of isotopically anomalous xenon which was trapped in the meteorites.

  13. High fidelity equation of state for xenon : integrating experiments and first principles simulations in developing a wide-range equation of state model for a fifth-row element.

    SciTech Connect

    Flicker, Dawn G.; Root, Seth; Mattsson, Thomas Kjell Rene; Magyar, Rudolph J.; Carpenter, John H.

    2010-05-01

    The noble gas xenon is a particularly interesting element. At standard pressure xenon is an fcc solid which melts at 161 K and then boils at 165 K, thus displaying a rather narrow liquid range on the phase diagram. On the other hand, under pressure the melting point is significantly higher: 3000 K at 30 GPa. Under shock compression, electronic excitations become important at 40 GPa. Finally, xenon forms stable molecules with fluorine (XeF{sub 2}) suggesting that the electronic structure is significantly more complex than expected for a noble gas. With these reasons in mind, we studied the xenon Hugoniot using DFT/QMD and validated the simulations with multi-Mbar shock compression experiments. The results show that existing equation of state models lack fidelity and so we developed a wide-range free-energy based equation of state using experimental data and results from first-principles simulations.

  14. Recovering Residual Xenon Propellant for an Ion Propulsion System

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani; Skakkottai, P.; wu, Jiunn Jeng

    2006-01-01

    Future nuclear-powered Ion-Propulsion- System-propelled spacecraft such as Jupiter Icy Moon Orbiter (JIMO) will carry more than 10,000 kg of xenon propellant. Typically, a small percentage of this propellant cannot be used towards the end of the mission because of the pressure drop requirements for maintaining flow. For large missions such as JIMO, this could easily translate to over 250 kg of unusable xenon. A proposed system, the Xenon Recovery System (XRS), for recovering almost all of the xenon remaining in the tank, would include a cryopump in the form of a condenser/evaporator that would be alternatively cooled by a radiator, then heated electrically. When the pressure of the xenon in the tank falls below 0.7 MPa (100 psia), the previously isolated XRS will be brought online and the gas from the tank would enter the cryopump that is initially cooled to a temperature below saturation temperature of xenon. This causes xenon liquefaction and further cryopumping from the tank till the cryopump is full of liquid xenon. At this point, the cryopump is heated electrically by small heaters (70 to 80 W) to evaporate the liquid that is collected as high-pressure gas (<7 MPa; 1,000 psia) in an intermediate accumulator. Check valves between the tank and the XRS prevent the reverse flow of xenon during the heating cycle. The accumulator serves as the high-pressure source of xenon gas to the Xenon Feed System (XFS) downstream of the XRS. This cycle is repeated till almost all the xenon is recovered. Currently, this system is being baselined for JIMO.

  15. Offshore drilling, construction: Fortunes tied to stable gas prices

    SciTech Connect

    Pagano, S.S.; Marsh, T.

    1993-01-01

    Significantly improved US natural gas prices fueled an upswing in offshore drilling in the Gulf of Mexico in late 1992. Stabilized gas prices will be necessary to support both the off-shore drilling and construction markets in 1993 and beyond. The article discusses both these segments in detail: offshore drilling and offshore construction.

  16. Absolute Electron Extraction Efficiency of Liquid Xenon

    NASA Astrophysics Data System (ADS)

    Kamdin, Katayun; Mizrachi, Eli; Morad, James; Sorensen, Peter

    2016-03-01

    Dual phase liquid/gas xenon time projection chambers (TPCs) currently set the world's most sensitive limits on weakly interacting massive particles (WIMPs), a favored dark matter candidate. These detectors rely on extracting electrons from liquid xenon into gaseous xenon, where they produce proportional scintillation. The proportional scintillation from the extracted electrons serves to internally amplify the WIMP signal; even a single extracted electron is detectable. Credible dark matter searches can proceed with electron extraction efficiency (EEE) lower than 100%. However, electrons systematically left at the liquid/gas boundary are a concern. Possible effects include spontaneous single or multi-electron proportional scintillation signals in the gas, or charging of the liquid/gas interface or detector materials. Understanding EEE is consequently a serious concern for this class of rare event search detectors. Previous EEE measurements have mostly been relative, not absolute, assuming efficiency plateaus at 100%. I will present an absolute EEE measurement with a small liquid/gas xenon TPC test bed located at Lawrence Berkeley National Laboratory.

  17. A xenon ionization detector for scanned projection radiography: Xenon/Freon 13B1 comparison.

    PubMed

    Drost, D J; Mehuys, D; Fenster, A

    1984-01-01

    In a companion paper, we reported on the construction and testing of a xenon gas ionization detector for use in line scanned projection radiography. Experimental results indicate that the detector has sufficient resolution for chest radiography, but higher resolution is required for mammography. Theoretical analysis suggested that a detector pressurized with Freon 13B1 would have better resolution and higher x-ray energy efficiency than a xenon-filled detector for energies below 60 keV. In this paper we compared, theoretically and experimentally, Freon 13B1 to xenon as the detector gas. For a 120-kVp x-ray spectrum, the detector filled with 2.0 MPa of xenon had less channel-to-channel crosstalk, a higher quantum efficiency (QE), and twice the output signal than the detector filled with 1.4 MPa of Freon (highest possible pressure at room temperature), while for a 60-kVp spectrum, crosstalk is the same, but the detector has slightly higher QE and 1.4 times the energy efficiency when filled with Freon instead of xenon. We conclude that xenon is better for high-kVp imaging, while Freon at a lower pressure is slightly better for low-kVp imaging.

  18. Adsorption of xenon ions onto defects in organic surfaces: Implications for the origin and the nature of organics in primitive meteorites

    NASA Astrophysics Data System (ADS)

    Marrocchi, Yves; Marty, Bernard; Reinhardt, Peter; Robert, François

    2011-10-01

    Noble gases trapped in primitive meteorites are quantitatively hosted by a poorly defined organic phase, labeled phase Q. Xenon is enriched in heavy isotopes by +1.30 ± 0.06% per atomic mass unit (amu, 1 σ) in phase Q relative to solar. To understand the origin of this fractionation, we have performed adsorption experiments of xenon atoms and ions, ionized in a radiofrequency plasma. Within the reaction vessel, anthracite was heated and the resulting smoke deposited onto the walls of the vessel, resulting in carbon-rich films. Xenon was trapped in the carbon films either as ions in the ionization zone of the vessel, or as neutral atoms outside this zone. Xenon trapped as ionic Xe is tightly bound and is enriched by +1.36 ± 0.05%/amu (1 σ) in heavy isotopes, reproducing the isotopic fractionation of xenon trapped in phase Q relative to solar. Neutral xenon is more loosely trapped, is in much lower concentration, and is not isotopically fractionated. Ionized conditions allow the constant xenon isotopic composition observed in meteorite during stepwise heating release to be reproduced. Furthermore, the trapping efficiency of Xe + estimated from these experiments is consistent with the high xenon concentration measured in phase Q of primitives meteorites. Xenon was not trapped in the film by implantation because the energies of the incident Xe atoms and ions were far too low (<1 eV). From the difference of behavior between ionic and neutral forms, we propose that xenon ions were trapped via chemical bonding at the surface of the newly created C-rich film. The observed mass-dependent fractionation of xenon is unlikely to have occurred in the gas phase. It is more probably related to variations in chemical bonding strengths of Xe isotopes as chemical bonds involving heavy Xe isotopes are more stable than those involving light ones. For young stars, including the young Sun, photons emitted in the far UV energy range able to ionize noble gases (<100 nm) were orders of

  19. Xenon International Automated Control

    SciTech Connect

    2016-08-05

    The Xenon International Automated Control software monitors, displays status, and allows for manual operator control as well as fully automatic control of multiple commercial and PNNL designed hardware components to generate and transmit atmospheric radioxenon concentration measurements every six hours.

  20. The Xenon record of Earth's early differentiaiton

    NASA Astrophysics Data System (ADS)

    Peto, M. K.; Mukhopadhyay, S.; Kelley, K. A.

    2011-12-01

    Xenon isotopes in mantle derived rocks provide information on the early differentiation of the silicate mantle of our planet. {131,132 134,136}Xe isotopes are produced by the spontaneous fission of two different elements: the now extinct radionuclide 244Pu, and the long-lived 238U. These two parent nuclides, however, yield rather different proportion of fissiogenic Xenon isotopes. Hence, the proportion of Pu- to U-derived fission xenon is indicative of the degree and rate of outgassing of a mantle reservoir. Recent data obtained from Iceland in our lab confirm that the Xenon isotopic composition of the plume source(s) is characterized by lower 136Xe/130Xe ratios than the MORB source and the Iceland plume is more enriched in the Pu-derived Xenon component. These features are interpreted as reflecting different degrees of outgassing and appear not to be the result of preferential recycling of Xenon to the deep mantle. To further investigate how representative the Icelandic measurements might be of other mantle plumes, we measured noble gases (He, Ne, Ar, Xe) in gas-rich basalt glasses from the Rochambeau Ridge (RR) in the Northern Lau Basin. Recent work suggests the presence of a "Samoan-like" OIB source in the northern Lau Basin and our measurements were performed on samples with plume-like 3He/4He ratios (15-28 RA) [1]. The Xenon isotopic measurements indicate that the maximum measured 136Xe/130Xe ratios in the Rochambeau samples are similar to Iceland. In particular, for one of the gas rich samples we were able to obtain 77 different isotopic measurements through step-crushing. Preliminary investigation of this sample suggests higher Pu- to U-derived fission Xenon than in MORBs. To quantitatively evaluate the degree and rate of outgassing of the plume and MORB reservoirs, particularly during the first few hundred million years of Earth's history, we have modified a geochemical reservoir model that was previously developed to investigate mantle overturn and mixing

  1. HXeOBr in a xenon matrix

    SciTech Connect

    Khriachtchev, Leonid; Tapio, Salla; Domanskaya, Alexandra V.; Raesaenen, Markku; Isokoski, Karoliina; Lundell, Jan

    2011-03-28

    We report on a new noble-gas molecule HXeOBr prepared in a low-temperature xenon matrix from the HBr and N{sub 2}O precursors by UV photolysis and thermal annealing. This molecule is assigned with the help of deuteration experiments and ab initio calculations including anharmonic methods. The H-Xe stretching frequency of HXeOBr is observed at 1634 cm{sup -1}, which is larger by 56 cm{sup -1} than the frequency of HXeOH identified previously. The experiments show a higher thermal stability of HXeOBr molecules in a xenon matrix compared to HXeOH.

  2. Theoretical Modeling of - and Infrared - High-Pressure Gas Lasers with Application to the Xenon Chloride Laser

    NASA Astrophysics Data System (ADS)

    Ishihara, Toshihiko

    Theoretical modeling of microwave- and infrared -pumped high-pressure gas lasers is presented. The theoretical model consists of the time-averaged Boltzmann equation to calculate the electron velocity distribution function under the influence of an alternating electric field, a set of first-order ordinary differential equations to calculate the temporal evolution of the laser plasma, the laser photon balance equation to calculate the instantaneous laser output power, and the time history of the strength of the pumping power. The first law of thermodynamics is employed to determine the root-mean-square strength of the electric field acting on the laser plasma tube by matching the input power and the absorbed power. The theoretical model assumes that the chemical species are homogeneously distributed in an excited plasma and that the laser photons are uniformly distributed inside an optical cavity. Any adverse effects of the plasma tube wall are ignored to simplify the analysis. The theoretical modeling is numerically applied to a microwave-pumped XeCl laser pumped by a 915 MHz microwave of 450 nsec pulse duration. The calculated laser pulse is in fair agreement with the experimentally observed laser pulse. The plasma tube wall is considered to have a significant effect on the performance of the laser when the surface to volume ratio of the plasma tube is large. A parametric study of the microwave-pumped He -base XeCl laser is numerically done using the theoretical model. Among all the calculations done, the gas mixture of He/Xe/HCI = 1000/10/1.3 gives the best performance at the total pressure of 3.5 atm. The result is in good agreement with experimental observation. The theoretical modeling is extended to the infrared -pumped high-pressure XeCl laser. The laser plasma can be heated to a higher electron number density by the infrared beam than by the microwave. This fact may help the production of the laser upper-state molecules which are formed via the electron

  3. Initial experimental demonstration of the principles of a xenon gas shield designed to protect optical components from soft x-ray induced opacity (blanking) in high energy density experiments

    DOE PAGES

    Swadling, G. F.; Ross, J. S.; Manha, D.; ...

    2017-03-16

    The design principles of a xenon gas shield device that is intended to protect optical components from x-ray induced opacity (“x-ray blanking”) have been experimentally demonstrated at the OMEGA-60 Laser Facility at the Laboratory for Laser Energetics, University of Rochester. A volume of xenon gas placed in front of an optical component absorbs the incoming soft x-ray radiation but transmits optical and ultra-violet radiation. The time-resolved optical (532 nm) transmission of samples was recorded as they were exposed to soft x-rays produced by a gold sphere source (1.5 kJ sr$-$1, 250–300 eV). Blanking of fused silica (SiO2) was measured tomore » occur over a range of time-integrated soft x-ray (<3 keV) fluence from ~0.2–2.5 J cm$-$2. A shield test device consisting of a 30 nm silicon nitride (Si3N4) and a 10 cm long volume of 0.04 bar xenon gas succeeded in delaying loss of transmission through a magnesium fluoride sample; optical transmission was observed over a longer period than for the unprotected sample. It is hoped that the design of this x-ray shield can be scaled in order to produce a shield device for the National Ignition Facility optical Thomson scattering collection telescope, in order to allow measurements of hohlraum plasma conditions produced in inertial confinement fusion experiments. Finally, if successful, it will also have applications in many other high energy density experiments where optical and ultra-violet measurements are desirable.« less

  4. Initial experimental demonstration of the principles of a xenon gas shield designed to protect optical components from soft x-ray induced opacity (blanking) in high energy density experiments

    NASA Astrophysics Data System (ADS)

    Swadling, G. F.; Ross, J. S.; Manha, D.; Galbraith, J.; Datte, P.; Sorce, C.; Katz, J.; Froula, D. H.; Widmann, K.; Jones, O. S.; Divol, L.; Landen, O. L.; Kilkenny, J. D.; Moody, J. D.

    2017-03-01

    The design principles of a xenon gas shield device that is intended to protect optical components from x-ray induced opacity ("x-ray blanking") have been experimentally demonstrated at the OMEGA-60 Laser Facility at the Laboratory for Laser Energetics, University of Rochester. A volume of xenon gas placed in front of an optical component absorbs the incoming soft x-ray radiation but transmits optical and ultra-violet radiation. The time-resolved optical (532 nm) transmission of samples was recorded as they were exposed to soft x-rays produced by a gold sphere source (1.5 kJ sr-1, 250-300 eV). Blanking of fused silica (SiO2) was measured to occur over a range of time-integrated soft x-ray (<3 keV) fluence from ˜0.2-2.5 J cm-2. A shield test device consisting of a 30 nm silicon nitride (Si3N4) and a 10 cm long volume of 0.04 bar xenon gas succeeded in delaying loss of transmission through a magnesium fluoride sample; optical transmission was observed over a longer period than for the unprotected sample. It is hoped that the design of this x-ray shield can be scaled in order to produce a shield device for the National Ignition Facility optical Thomson scattering collection telescope, in order to allow measurements of hohlraum plasma conditions produced in inertial confinement fusion experiments. If successful, it will also have applications in many other high energy density experiments where optical and ultra-violet measurements are desirable.

  5. Core level photoelectron spectroscopy probed heterogeneous xenon/neon clusters

    NASA Astrophysics Data System (ADS)

    Pokapanich, Wandared; Björneholm, Olle; Öhrwall, Gunnar; Tchaplyguine, Maxim

    2017-06-01

    Binary rare gas clusters; xenon and neon which have a significant contrariety between sizes, produced by a co-expansion set up and have been studied using synchrotron radiation based x-ray photoelectron spectroscopy. Concentration ratios of the heterogeneous clusters; 1%, 3%, 5% and 10% were controlled. The core level spectra were used to determine structure of the mixed cluster and analyzed by considering screening mechanisms. Furthermore, electron binding energy shift calculations demonstrated cluster aggregation models which may occur in such process. The results showed that in the case of low mixing ratios of 3% and 5% of xenon in neon, the geometric structures exhibit xenon in the center and xenon/neon interfaced in the outer shells. However, neon cluster vanished when the concentration of xenon was increased to 10%.

  6. Probing Toluene and Ethylbenzene Stable Glass Formation using Inert Gas Permeation

    SciTech Connect

    Smith, R. Scott; May, Robert A.; Kay, Bruce D.

    2015-09-01

    Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (Tdep) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at Tdep = 0.92 Tg, although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 Tg. Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 Tg and formed stable glasses from 0.81 to 0.96 Tg. These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.

  7. Background Discrimination Capability of a Dual Phase Xenon Detector for the XENON Dark Matter Experiment

    NASA Astrophysics Data System (ADS)

    Ni, Kaixuan

    2005-04-01

    The XENON experiment aims at searching for dark matter WIMPs via their elastic scattering off Xe nuclei. The detector is a dual phase (liquid/gas) xenon time projection chamber, which allows event-by-event discrimination through the different ratio of ionization (charge) and scintillation (light) signals produced in liquid xenon by nuclear recoils (WIMPs and neutrons) and by electron recoils (electrons and gammas). In the dual phase detector, the ionization signal is detected via proportional scintillation light produced by accelerated electrons extracted from the liquid to the gas. I will demonstrate the performance of event type discrimination of a dual phase xenon prototype with seven photomultiplier-tubes (PMTs) for detecting direct scintillation (S1) and proportional scintillation (S2) signals simultaneously. The values of S2/S1 were measured for electron (Co-57) and alpha (Po-210) recoils, with a difference about a factor of 30. A preliminary result of S2/S1 from nuclear recoils (Am-Be) will also be presented. Based on the distribution of S2 signals over the seven PMTs, an algorithm was developed to reconstruct the event positions, which shows promising capability to further reject background events from the detector surface. The background discrimination capability of a larger scale (10 kg) detector (XENON10) will be shown from detailed Monte Carlo simulations.

  8. Antiapoptotic activity of argon and xenon.

    PubMed

    Spaggiari, Sabrina; Kepp, Oliver; Rello-Varona, Santiago; Chaba, Kariman; Adjemian, Sandy; Pype, Jan; Galluzzi, Lorenzo; Lemaire, Marc; Kroemer, Guido

    2013-08-15

    Although chemically non-reactive, inert noble gases may influence multiple physiological and pathological processes via hitherto uncharacterized physical effects. Here we report a cell-based detection system for assessing the effects of pre-defined gas mixtures on the induction of apoptotic cell death. In this setting, the conventional atmosphere for cell culture was substituted with gas combinations, including the same amount of oxygen (20%) and carbon dioxide (5%) but 75% helium, neon, argon, krypton, or xenon instead of nitrogen. The replacement of nitrogen with noble gases per se had no effects on the viability of cultured human osteosarcoma cells in vitro. Conversely, argon and xenon (but not helium, neon, and krypton) significantly limited cell loss induced by the broad-spectrum tyrosine kinase inhibitor staurosporine, the DNA-damaging agent mitoxantrone and several mitochondrial toxins. Such cytoprotective effects were coupled to the maintenance of mitochondrial integrity, as demonstrated by means of a mitochondrial transmembrane potential-sensitive dye and by assessing the release of cytochrome c into the cytosol. In line with this notion, argon and xenon inhibited the apoptotic activation of caspase-3, as determined by immunofluorescence microscopy coupled to automated image analysis. The antiapoptotic activity of argon and xenon may explain their clinically relevant cytoprotective effects.

  9. Antiapoptotic activity of argon and xenon

    PubMed Central

    Spaggiari, Sabrina; Kepp, Oliver; Rello-Varona, Santiago; Chaba, Kariman; Adjemian, Sandy; Pype, Jan; Galluzzi, Lorenzo; Lemaire, Marc; Kroemer, Guido

    2013-01-01

    Although chemically non-reactive, inert noble gases may influence multiple physiological and pathological processes via hitherto uncharacterized physical effects. Here we report a cell-based detection system for assessing the effects of pre-defined gas mixtures on the induction of apoptotic cell death. In this setting, the conventional atmosphere for cell culture was substituted with gas combinations, including the same amount of oxygen (20%) and carbon dioxide (5%) but 75% helium, neon, argon, krypton, or xenon instead of nitrogen. The replacement of nitrogen with noble gases per se had no effects on the viability of cultured human osteosarcoma cells in vitro. Conversely, argon and xenon (but not helium, neon, and krypton) significantly limited cell loss induced by the broad-spectrum tyrosine kinase inhibitor staurosporine, the DNA-damaging agent mitoxantrone and several mitochondrial toxins. Such cytoprotective effects were coupled to the maintenance of mitochondrial integrity, as demonstrated by means of a mitochondrial transmembrane potential-sensitive dye and by assessing the release of cytochrome c into the cytosol. In line with this notion, argon and xenon inhibited the apoptotic activation of caspase-3, as determined by immunofluorescence microscopy coupled to automated image analysis. The antiapoptotic activity of argon and xenon may explain their clinically relevant cytoprotective effects. PMID:23907115

  10. Scalability study of solid xenon

    SciTech Connect

    Yoo, J.; Cease, H.; Jaskierny, W. F.; Markley, D.; Pahlka, R. B.; Balakishiyeva, D.; Saab, T.; Filipenko, M.

    2015-04-01

    We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified {\\it Bridgeman's technique} reproduces a large scale optically transparent solid xenon.

  11. Separation and purification of xenon

    DOEpatents

    Schlea, deceased, Carl Solomon

    1978-03-14

    Xenon is separated from a mixture of xenon and krypton by extractive distillation using carbon tetrafluoride as the partitioning agent. Krypton is flushed out of the distillation column with CF.sub.4 in the gaseous overhead stream while purified xenon is recovered from the liquid bottoms. The distillation is conducted at about atmospheric pressure or at subatmospheric pressure.

  12. The nonlinear model for emergence of stable conditions in gas mixture in force field

    NASA Astrophysics Data System (ADS)

    Kalutskov, Oleg; Uvarova, Liudmila

    2016-06-01

    The case of M-component liquid evaporation from the straight cylindrical capillary into N - component gas mixture in presence of external forces was reviewed. It is assumed that the gas mixture is not ideal. The stable states in gas phase can be formed during the evaporation process for the certain model parameter valuesbecause of the mass transfer initial equationsnonlinearity. The critical concentrations of the resulting gas mixture components (the critical component concentrations at which the stable states occur in mixture) were determined mathematically for the case of single-component fluid evaporation into two-component atmosphere. It was concluded that this equilibrium concentration ratio of the mixture components can be achieved by external force influence on the mass transfer processes. It is one of the ways to create sustainable gas clusters that can be used effectively in modern nanotechnology.

  13. Stable Isotope Measurements of Carbon Dioxide, Methane, and Hydrogen Sulfide Gas Using Frequency Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nowak-Lovato, K.

    2014-12-01

    Seepage from enhanced oil recovery, carbon storage, and natural gas sites can emit trace gases such as carbon dioxide, methane, and hydrogen sulfide. Trace gas emission at these locations demonstrate unique light stable isotope signatures that provide information to enable source identification of the material. Light stable isotope detection through surface monitoring, offers the ability to distinguish between trace gases emitted from sources such as, biological (fertilizers and wastes), mineral (coal or seams), or liquid organic systems (oil and gas reservoirs). To make light stable isotope measurements, we employ the ultra-sensitive technique, frequency modulation spectroscopy (FMS). FMS is an absorption technique with sensitivity enhancements approximately 100-1000x more than standard absorption spectroscopy with the advantage of providing stable isotope signature information. We have developed an integrated in situ (point source) system that measures carbon dioxide, methane and hydrogen sulfide with isotopic resolution and enhanced sensitivity. The in situ instrument involves the continuous collection of air and records the stable isotope ratio for the gas being detected. We have included in-line flask collection points to obtain gas samples for validation of isotopic concentrations using our in-house isotope ratio mass spectroscopy (IRMS). We present calibration curves for each species addressed above to demonstrate the sensitivity and accuracy of the system. We also show field deployment data demonstrating the capabilities of the system in making live dynamic measurements from an active source.

  14. Purging means and method for Xenon arc lamps

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1973-01-01

    High pressure Xenon short-arc lamp with two reservoirs which are selectively connectable to the lamp's envelope is described. One reservoir contains an absorbent which will absorb both Xenon and contaminant gases such as CO2 and O2. The absorbent temperature is controlled to evacuate the envelope of both the Xenon and the contaminant gases. The temperature of the absorbent is then raised to desorb only clean Xenon while retaining the contaminant gases, thereby clearing the envelope of the contaminant gases. The second reservoir contains a gas whose specific purpose is, to remove the objectional metal film which deposits gradually on the interior surface of the lamp envelope during normal arc operation. The origin of the film is metal transferred from the cathode of the arc lamp by sputtering or other gas transfer processes.

  15. Requirements for Xenon International

    SciTech Connect

    Hayes, James C.; Ely, James H.

    2013-09-26

    This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

  16. Requirements for Xenon International

    SciTech Connect

    Hayes, James C.; Ely, James H.; Haas, Derek A.; Harper, Warren W.; Heimbigner, Tom R.; Hubbard, Charles W.; Humble, Paul H.; Madison, Jill C.; Morris, Scott J.; Panisko, Mark E.; Ripplinger, Mike D.; Stewart, Timothy L.

    2015-12-30

    This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

  17. XENON100 Dark Matter Search: Scintillation Response of Liquid Xenon to Electronic Recoils

    NASA Astrophysics Data System (ADS)

    Lim, Kyungeun Elizabeth

    Dark matter is one of the missing pieces necessary to complete the puzzle of the universe. Numerous astrophysical observations at all scales suggest that 23 % of the universe is made of nonluminous, cold, collisionless, nonbaryonic, yet undiscovered dark matter. Weakly Interacting Massive Particles (WIMPs) are the most well-motivated dark matter candidates and significant efforts have been made to search for WIMPs. The XENON100 dark matter experiment is currently the most sensitive experiment in the global race for the first direct detection of WIMP dark matter. XENON100 is a dual-phase (liquid-gas) time projection chamber containing a total of 161 kg of liquid xenon (LXe) with a 62kg WIMP target mass. It has been built with radiopure materials to achieve an ultra-low electromagnetic background and operated at the Laboratori Nazionali del Gran Sasso in Italy. WIMPs are expected to scatter off xenon nuclei in the target volume. Simultaneous measurement of ionization and scintillation produced by nuclear recoils allows for the detection of WIMPs in XENON100. Data from the XENON100 experiment have resulted in the most stringent limits on the spin-independent elastic WIMP-nucleon scattering cross sections for most of the significant WIMP masses. As the experimental precision increases, a better understanding of the scintillation and ionization response of LXe to low energy (< 10 keV) particles is crucial for the interpretation of data from LXe based WIMP searches. A setup has been built and operated at Columbia University to measure the scintillation response of LXe to both electronic and nuclear recoils down to energies of a few keV, in particular for the XENON100 experiment. In this thesis, I present the research carried out in the context of the XENON100 dark matter search experiment. For the theoretical foundation of the XENON100 experiment, the first two chapters are dedicated to the motivation for and detection medium choice of the XENON100 experiment

  18. The Development of the improved equipment for the measurement radionuclides of xenon in atmospheric air

    NASA Astrophysics Data System (ADS)

    Pakhomov, S. A.; Dubasov, Y. V.

    2009-04-01

    The Radium Khlopin Institute have developed the mobile (vehicle based) equipment attended for the providing of the monitoring of radioactive xenon isotopes in atmospheric air on territories, neighboring with NPP. This equipment comprises the improved sampling installation with sample-processing unit and specialized spectrometer of β-γ-coincidences. The principal specificity of sampling installation is the using of the gas-cooling machine attended for the reaching of the cryogenic temperatures, which works without helium, using for cooling the processed air itself. The capacity of sampling reaches 20 cubic meters per hour with the xenon extraction factor of 75%. The duration of the sampling cycle forms 3 - 7 hours depending of the xenon volume requirements. The sample-processing unit is designed on preparative gas chromatograph scheme. Duration of sample-processing procedure does not exceed one and half hour. The volume of the prepared sample is around half liter, it contains 3 - 7 cubic centimeters of the xenon, depending of sampling cycle time. For measurements of xenon radioisotopes containing in obtained sample, was developed a β-γ-coincidences spectrometer on the base of the "ORTEC" HP Ge detector equipped with scintillation β-detector designed as Marinelli chamber of 700 cm3 volume. This spectrometer allows to reduce the ambient background more than in 20 times, with γ-channel efficiency reduction not more than in 1.5 times. The minimum detectable activity of 133Хе (MDA), evaluated by Currie formula for probability 95 % is 0.05 Bq at the exposition of 20 hours. Spectrometer is also intended for determination of the stable krypton and xenon concentrations in β-chamber by X-ray-fluorescent method. Therefore, in a shield of the spectrometer collimating pinhole is made and 241Am source is installed. To improve the sensitivity of the analysis beryllium window is made in β-chamber wall, adjoining to the HPGe detector. X-ray-fluorescent analysis allows to

  19. Doppler-Free Spectroscopy Measurements of Isotope Shifts and Hyperfine Components of Near-IR Xenon Lines

    SciTech Connect

    Mazouffre, S.; Pawelec, E.; Tran Bich, N.; Sadeghi, N.

    2006-01-15

    Xenon is currently used as propellant gas in electric thrusters, in which ejection of corresponding ions produces the desired thrust. As such a gas contains 9 stable isotopes, a non-intrusive determination of the velocity distribution function of atoms and ions in the thruster plasma plume, by means of absorption or fluorescence techniques, requires a precise knowledge of the line structure. We used Doppler-free Lamb-dip spectroscopy to determine isotopic shifts and hyperfine components of odd isotopes of several spectral lines of Xe atom and Xe+ ion in the 825 - 835 nm range.

  20. Xenon and iodine reveal multiple distinct exotic xenon components in Efremovka "nanodiamonds"

    NASA Astrophysics Data System (ADS)

    Gilmour, J. D.; Holland, G.; Verchovsky, A. B.; Fisenko, A. V.; Crowther, S. A.; Turner, G.

    2016-03-01

    We identify new xenon components in a nanodiamond-rich residue from the reduced CV3 chondrite Efremovka. We demonstrate for the first time that these, and the previously identified xenon components Xe-P3 and Xe-P6, are associated with elevated I/Xe ratios. The 129I/127I ratio associated with xenon loss from these presolar compositions during processing on planetesimals in the early solar system was (0.369 ± 0.019) × 10-4, a factor of 3-4 lower than the canonical value. This suggests either incorporation of iodine into carbonaceous grains before the last input of freshly synthesized 129I to the solar system's precursor material, or loss of noble gases during processing of planetesimals around 30 Myr after solar system formation. The xenon/iodine ratios and model closure ages were revealed by laser step pyrolysis analysis of a neutron-irradiated, coarse-grained nanodiamond separate. Three distinct low temperature compositions are identified by characteristic I/Xe ratios and 136Xe/132Xe ratios. There is some evidence of multiple compositions with distinct I/Xe ratios in the higher temperature releases associated with Xe-P6. The presence of iodine alongside Q-Xe and these components in nanodiamonds constrains the pathway by which extreme volatiles entered the solid phase and may facilitate the identification of their carriers. There is no detectable iodine contribution to the presolar Xe-HL component, which is released at intermediate temperatures; this suggests a distinct trapping process. Releases associated with the other components all include significant contributions of 128Xe produced from iodine by neutron capture during reactor irradiation. We propose a revised model relating the origin of Xe-P3 (which exhibits an s-process deficit) through a ;Q-process; to the Q component (which makes the dominant contribution to the heavy noble gas budget of primitive material). The Q-process incorporates noble gases and iodine into specific carbonaceous phases with mass

  1. Terminal velocity of a buoyant gas bubble in the stable gas body approximation

    NASA Astrophysics Data System (ADS)

    Peluso, Fabio

    2017-05-01

    The terminal velocity for a bubble of gas is determined as a function of its volume and gas temperature, and pressure as an effect of buoyancy. Only volume variation is considered and not shape deformation. The limits of applicability of the expression arrived at for the terminal velocity as function of the bubble sphericity are given and some typical examples are discussed in detail.

  2. Converging xenon shock waves driven by megagauss magnetic fields

    SciTech Connect

    Shearer, J.W.; Steinberg, D.J.

    1986-07-01

    We attempted to implode a conducting metal linear at high velocity, and our failure to do so led to switching, or rapidly transferring the field from pushing an aluminum conductor to snow-plowing a half-atmosphere of xenon gas. We successfully initiated convergent xenon gas shocks with the use of a magnetohydrodynamic switch and coaxial high-explosive, flux-compression generators. Principal diagnostics used to study the imploding xenon gas were /sup 133/Xe radioactive tracers, continuous x-ray absorption, and neutron output. We compressed the xenon gas about five to sixfold at a velocity of 10 cm/..mu..s at a radius of 4 cm. The snowplow efficiency was good; going from 13- to 4-cm radius, we lost only about 20% of the mass. The temperature of the imploded sheath was determined by mixing deuterium with the xenon and measuring the neutron output. Using reasonable assumptions about the amount, density, and uniformity of the compressed gas, we estimate that we reached temperatures as high as 155 eV. Energy-loss mechanisms that we encountered included wall ablation and Taylor instabilities of the back surface.

  3. Gamma detectors based on high pressure xenon: their development and application

    NASA Astrophysics Data System (ADS)

    Ulin, Sergey E.; Dmitrenko, Valery V.; Grachev, V. M.; Uteshev, Z. M.; Vlasic, K. F.; Chernysheva, I. V.; Duhvalov, A. G.; Kotler, F. G.; Pushkin, K. N.

    2004-01-01

    Various modifications of xenon detectors and their parameters in comparison with gamma-detectors of other types are considered. Prospects of xenon detectors' applications in gamma-spectroscopy based on experimental results are discussed including detection and control of radioactive and fissile materials displacement, definition of uranium enrichment rate, and measurements of nuclear reactor radioactive gas waste concentration. Possibilities for xenon detector use for environmental control and measurement of cosmic gamma radiation on orbital stations are considered.

  4. Gamma detectors based on high-pressure xenon: their development and application

    NASA Astrophysics Data System (ADS)

    Ulin, Sergey E.; Dmitrenko, Valery V.; Grachev, V. M.; Uteshev, Z. M.; Vlasik, K. F.; Chernysheva, I. V.; Dukhvalov, A. G.; Kotler, F. G.; Pushkin, K. N.

    2004-10-01

    Various modifications of xenon detectors and their parameters in comparison with gamma-detectors of other types are considered. Prospects of xenon detectors' applicatins in gamma-spectroscopy based on experimental results are discussed including detection and control of radioactive and fissile materials displacement, definition of uranium enrichment rate, and measurements of nuclear reactor radioactive gas waste concentration. Possibilities for xenon detector use for environmental control and measurement of cosmic gamma radiation on orbital stations are considered.

  5. Modeling of the pressurized xenon gamma ray scintillation detector

    NASA Astrophysics Data System (ADS)

    Meek, Romney; Barzilov, Alexander; Novikov, Ivan

    2011-10-01

    We are developing a high pressure xenon detector for photon measurements. Xenon produces electroluminescence (EL) scintillation emission that we use as the primary signal in our strategy to acquire information. The detector consists of a high pressure chamber, a thin radiation input window with the supporting grid of collimator ribs and electrode grids to create the electric field, and a photo sensor -- the large area silicon avalanche photodiode. The electrode grids are made of thin wire. The modeling of the electric field is a crucial step in developing a working prototype. It has been previously shown that the uniform electric field divided by the number density of xenon gas needs to be above approximately 3 Td to give enough energy to ionize the xenon atoms, but less than 16 Td to prevent electron avalanches from occurring. The electric field was modeled using Comsol Multiphysics. This presentation discusses the results of electric field modeling for the detector (absorption, drift, and EL regions).

  6. High-pressure transformations in xenon hydrates

    PubMed Central

    Sanloup, Chrystèle; Mao, Ho-kwang; Hemley, Russell J.

    2002-01-01

    A high-pressure investigation of the Xe⋅H2O chemical system was conducted by using diamond-anvil cell techniques combined with in situ Raman spectroscopy, synchrotron x-ray diffraction, and laser heating. Structure I xenon clathrate was observed to be stable up to 1.8 GPa, at which pressure it transforms to a new Xe clathrate phase stable up to 2.5 GPa before breaking down to ice VII plus solid xenon. The bulk modulus and structure of both phases were determined: 9 ± 1 GPa for Xe clathrate A with structure I (cubic, a = 11.595 ± 0.003 Å, V = 1,558.9 ± 1.2 Å3 at 1.1 GPa) and 45 ± 5 GPa for Xe clathrate B (tetragonal, a = 8.320 ± 0.004 Å, c = 10.287 ± 0.007 Å, V = 712.1 ± 1.2 Å3 at 2.2 GPa). The extended pressure stability field of Xe clathrate structure I (A) and the discovery of a second Xe clathrate (B) above 1.8 GPa have implications for xenon in terrestrial and planetary interiors. PMID:11756690

  7. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

    PubMed Central

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images

  8. Photoionization detector for the detection of xenon light

    SciTech Connect

    Anderson, D.F.

    1980-01-01

    A photionization detector is described with a high quantum efficiency at wavelengths shorter than about 2000 A. This instrument, coupled to a xenon gas scintillation proportional counter has an energy resolution of 9.5% FWHM at 6 keV. The vapor pressure and absorption coefficient of TMAE are measured and the prospects of an imaging gas scintillation proportional counter are discussed.

  9. Probing Toluene and Ethylbenzene Stable Glass Formation Using Inert Gas Permeation.

    PubMed

    Smith, R Scott; May, R Alan; Kay, Bruce D

    2015-09-17

    Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (T(dep)) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at T(dep) = 0.92 T(g), although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 T(g). Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 T(g) and formed stable glasses from 0.81 to 0.96 T(g). These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.

  10. Assessing the depth of hypnosis of xenon anaesthesia with the EEG.

    PubMed

    Stuttmann, Ralph; Schultz, Arthur; Kneif, Thomas; Krauss, Terence; Schultz, Barbara

    2010-04-01

    Xenon was approved as an inhaled anaesthetic in Germany in 2005 and in other countries of the European Union in 2007. Owing to its low blood/gas partition coefficient, xenons effects on the central nervous system show a fast onset and offset and, even after long xenon anaesthetics, the wake-up times are very short. The aim of this study was to examine which electroencephalogram (EEG) stages are reached during xenon application and whether these stages can be identified by an automatic EEG classification. Therefore, EEG recordings were performed during xenon anaesthetics (EEG monitor: Narcotrend®). A total of 300 EEG epochs were assessed visually with regard to the EEG stages. These epochs were also classified automatically by the EEG monitor Narcotrend® using multivariate algorithms. There was a high correlation between visual and automatic classification (Spearman's rank correlation coefficient r=0.957, prediction probability Pk=0.949). Furthermore, it was observed that very deep stages of hypnosis were reached which are characterised by EEG activity in the low frequency range (delta waves). The burst suppression pattern was not seen. In deep hypnosis, in contrast to the xenon EEG, the propofol EEG was characterised by a marked superimposed higher frequency activity. To ensure an optimised dosage for the single patient, anaesthetic machines for xenon should be combined with EEG monitoring. To date, only a few anaesthetic machines for xenon are available. Because of the high price of xenon, new and further developments of machines focus on optimizing xenon consumption.

  11. Relative scintillation efficiency of liquid xenon in the XENON10 direct dark matter search

    NASA Astrophysics Data System (ADS)

    Manzur, Angel

    There is almost universal agreement that most of the mass in the Universe consists of dark matter. Many lines of reasoning suggest that the dark matter consists of a weakly interactive massive particle (WIMP) with mass ranging from 10 GeV/c 2 to a few TeV/c 2 . Today, numerous experiments aim for direct or indirect dark matter detection. XENON10 is a direct detection experiment using a xenon dual phase time projection chamber. Particles interacting with xenon will create a scintillation signal ( S 1) and ionization. The charge produced is extracted into the gas phase and converted into a proportional scintillation light ( S 2), with an external electric field. The dominant background, b particles and g rays, will undergo an electron recoil (ER) interaction, while WIMPs and neutrons will undergo a nuclear recoil (NR) interaction. Event-by-event discrimination of background signals is based on log 10 ( S 2/ S 1) NR < log 10 ( S 2/ S 1) ER and the 3-D position reconstruction. In 2006 the XENON10 detector started underground operations at laboratorio Nazionali del Gran Sasso in Italy. After 6 months of operations, totaling 58.6 live days and 5.4 kg of fiducial mass, XENON10 set the best upper limits at the time. Finding a spin- independent WIMP-nucleon cross-section s h = 8.8 × 10^-44 cm 2 and a spin- dependent WIMP-neutron cross-section s h = 1.0 × 10^-38 cm 2 for a WIMP mass of 100 GeV/c 2 (90% C.L.). In this work I give an overview of the dark matter evidence and review the requirements for a dark matter search. In particular I discuss the XENON10 detector, deployment, operation, calibrations, analysis and WIMP-nucleon cross- section limits. Finally, I present our latest results for the relative scintillation efficiency ([Special characters omitted.] ) for nuclear recoils in liquid xenon, which was the biggest source of uncertainty in the XENON10 limit. This quantity is essential to determine the nuclear energy scale and to determine the WIMP-nucleon cross

  12. Compact, stable and efficient all-fibre gas cells using hollow-core photonic crystal fibres

    NASA Astrophysics Data System (ADS)

    Benabid, F.; Couny, F.; Knight, J. C.; Birks, T. A.; Russell, P. St J.

    2005-03-01

    Gas-phase materials are used in a variety of laser-based applications-for example, in high-precision frequency measurement, quantum optics and nonlinear optics. Their full potential has however not been realized because of the lack of a suitable technology for creating gas cells that can guide light over long lengths in a single transverse mode while still offering a high level of integration in a practical and compact set-up or device. As a result, solid-phase materials are still often favoured, even when their performance compares unfavourably with gas-phase systems. Here we report the development of all-fibre gas cells that meet these challenges. Our structures are based on gas-filled hollow-core photonic crystal fibres, in which we have recently demonstrated substantially enhanced stimulated Raman scattering, and which exhibit high performance, excellent long-term pressure stability and ease of use. To illustrate the practical potential of these structures, we report two different devices: a hydrogen-filled cell for efficient generation of rotational Raman scattering using only quasi-continuous-wave laser pulses; and acetylene-filled cells, which we use for absolute frequency-locking of diode lasers with very high signal-to-noise ratios. The stable performance of these compact gas-phase devices could permit, for example, gas-phase laser devices incorporated in a `credit card' or even in a laser pointer.

  13. Xenon Feed System Progress (Postprint)

    DTIC Science & Technology

    2006-06-13

    development, assembly and test of an electric propulsion xenon feed system for a flight technology demonstration program. Major accomplishments...pressure transducer feedback, the PFCV has successfully fed xenon to a 200 watt Hall Effect Thruster in a Technology Demonstration Program. The feed

  14. Shear Thinning in Xenon

    NASA Technical Reports Server (NTRS)

    Bergm Robert F.; Moldover, Michael R.; Yao, Minwu; Zimmerli, Gregory A.

    2009-01-01

    We measured shear thinning, a viscosity decrease ordinarily associated with complex liquids such as molten plastics or ketchup, near the critical point of xenon. The data span a wide range of dimensionless shear rate: the product of the shear rate and the relaxation time of critical fluctuations was greater than 0.001 and was less than 700. As predicted by theory, shear thinning occurred when this product was greater than 1. The measurements were conducted aboard the Space Shuttle Columbia to avoid the density stratification caused by Earth's gravity.

  15. Minimum alveolar concentration (MAC) for sevoflurane and xenon at normothermia and hypothermia in newborn pigs.

    PubMed

    Liu, X; Dingley, J; Elstad, M; Scull-Brown, E; Steen, P A; Thoresen, M

    2013-05-01

    Neuroprotection from therapeutic hypothermia increases when combined with the anaesthetic gas xenon in animal studies. A clinical feasibility study of the combined treatment has been successfully undertaken in asphyxiated human term newborns. It is unknown whether xenon alone would be sufficient for sedation during hypothermia eliminating or reducing the need for other sedative or analgesic infusions in ventilated sick infants. Minimum alveolar concentration (MAC) of xenon is unknown in any neonatal species. Eight newborn pigs were anaesthetised with sevoflurane alone and then sevoflurane plus xenon at two temperatures. Pigs were randomised to start at either 38.5°C or 33.5°C. MAC for sevoflurane was determined using the claw clamp technique at the preset body temperature. For xenon MAC determination, a background of 0.5 MAC sevoflurane was used, and 60% xenon added to the gas mixture. The relationship between sevoflurane and xenon MAC is assumed to be additive. Xenon concentrations were changed in 5% steps until a positive clamp reaction was noted. Pigs' temperature was changed to the second target, and two MAC determinations for sevoflurane and 0.5 MAC sevoflurane plus xenon were repeated. MAC for sevoflurane was 4.1% [95% confidence interval (CI): 3.65-4.50] at 38.5°C and 3.05% (CI: 2.63-3.48) at 33.5°C, a significant reduction. MAC for xenon was 120% at 38.5°C and 116% at 33.5°C, not different. In newborn swine sevoflurane, MAC was temperature dependent, while xenon MAC was independent of temperature. There was large individual variability in xenon MAC, from 60% to 120%. © 2013 The Acta Anaesthesiologica Scandinavica Foundation.

  16. Development of Solid Xenon Bolometers

    NASA Astrophysics Data System (ADS)

    Dolinski, Michelle; Hansen, Erin

    2016-09-01

    Cryogenic liquid xenon detectors have become a popular technology in the search for rare events, such as dark matter interactions and neutrinoless double beta decay. The power of liquid xenon detector technology is in the combination of ionization and scintillation signals, resulting in particle discrimination and improved energy resolution over the ionization-only signal. The improved energy resolution results from a microscopic anti-correlation phenomenon that has not been described from first principles. Solid xenon bolometers operated at 10 mK are expected to have excellent counting statistics in the phonon channel, with energy resolution of 0.1% or better. This additional energy channel may offer the final piece of the puzzle in understanding liquid xenon detector energy response. We present work toward the development and characterization of solid xenon bolometers at Drexel University. Funding for this project was provided by the Charles E. Kaufman Foundation of The Pittsburgh Foundation.

  17. Online ^{222}Rn removal by cryogenic distillation in the XENON100 experiment

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Gangi, P. Di; Giovanni, A. Di; Diglio, S.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Calloch, M. Le; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Cristescu, I.

    2017-06-01

    We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant ^{222}Rn background originating from radon emanation. After inserting an auxiliary ^{222}Rn emanation source in the gas loop, we determined a radon reduction factor of R > 27 (95% C.L.) for the distillation column by monitoring the ^{222}Rn activity concentration inside the XENON100 detector.

  18. Determination of time-course change rate for arterial xenon using the time course of tissue xenon concentration in xenon-enhanced computed tomography

    SciTech Connect

    Sase, Shigeru; Takahashi, Hideaki; Ikeda, Hiroki; Kobayashi, Minoru; Matsumoto, Nobuyuki; Suzuki, Michihiro

    2008-06-15

    In calculating tissue blood flow (TBF) according to the Fick principle, time-course information on arterial tracer concentration is indispensable and has a considerable influence on the accuracy of calculated TBF. In TBF measurement by xenon-enhanced computed tomography (Xe-CT), nonradioactive xenon gas is administered by inhalation as a tracer, and end-tidal xenon is used as a substitute for arterial xenon. There has been the assumption that the time-course change rate for end-tidal xenon concentration (Ke) and that for arterial xenon concentration (Ka) are substantially equal. Respiratory gas sampling is noninvasive to the patient and Ke can be easily measured by exponential curve fitting to end-tidal xenon concentrations. However, it is pointed out that there would be a large difference between Ke and Ka in many cases. The purpose of this work was to develop a method of determining the Ka value using the time course of tissue xenon concentration in Xe-CT. The authors incorporated Ka into the Kety autoradiographic equation as a parameter to be solved, and developed a method of least-squares to obtain the solution for Ka from the time-course changes in xenon concentration in the tissue. The authors applied this method of least-squares to the data from Xe-CT abdominal studies performed on 17 patients; the solution for Ka was found pixel by pixel in the spleen, and its Ka map was created for each patient. On the one hand, the authors obtained the average value of the Ka map of the spleen as the calculated Ka (Ka{sub calc}) for each patient. On the other hand, the authors measured Ka (Ka{sub meas}) using the time-course changes in CT enhancement in the abdominal aorta for each patient. There was a good correlation between Ka{sub calc} and Ka{sub meas} (r=0.966, P<0.0001), and these two Ka values were close to each other (Ka{sub calc}=0.935xKa{sub meas}+0.089). This demonstrates that Ka{sub calc} would be close to the true Ka value. Accuracy of TBF by Xe-CT can be

  19. Xenon-enhanced CT imaging of local pulmonary ventilation

    NASA Astrophysics Data System (ADS)

    Tajik, Jehangir K.; Tran, Binh Q.; Hoffman, Eric A.

    1996-04-01

    We are using the unique features of electron beam CT (EBCT) in conjunction with respiratory and cardiac gating to explore the use of non-radioactive xenon gas as a pulmonary ventilation contrast agent. The goal is to construct accurate and quantitative high-resolution maps of local pulmonary ventilation in humans. We are evaluating xenon-enhanced computed tomography in the pig model with dynamic tracer washout/dilution and single breath inhalation imaging protocols. Scanning is done via an EBCT scanner which offers 50 msec scan aperture speeds. CT attenuation coefficients (image gray scale value) show a linear increase with xenon concentration (r equals 0.99). We measure a 1.55 Hounsfield Unit (HU) enhancement (kV equals 130, mA equals 623) per percentage increase in xenon gas concentration giving an approximately 155 HU enhancement with 100% xenon gas concentration as measured in a plexiglass super-syringe. Early results indicate that a single breath (from functional residual capacity to total lung capacity) of 100% xenon gas provides an average 32 +/- 1.85 (SE) HU enhancement in the lung parenchyma (maximum 50 HU) and should not encounter unwanted xenon side effects. However, changes in lung density occurring during even short breath holds (as short as 10 seconds) may limit using a single breath technique to synchronous volumetric scanning, currently possible only with EBCT. Preliminary results indicate close agreement between measured regional xenon concentration-time curves and theoretical predictions for the same sample. More than 10 breaths with inspirations to as high as 25 cmH2O airway pressure were needed to clear tracer from all lung regions and some regions had nearly linear rather than mono-exponential clearance curves. When regional parenchymal xenon concentration-time curves were analyzed, vertical gradients in ventilation and redistribution of ventilation at higher inspiratory flow rates were consistent with known pulmonary physiology. We present

  20. Xenon Diffusivity in Thoria-Urania Fuel

    SciTech Connect

    Kim, Heemoon; Park, Kwangheon; Kim, Bong Goo; Choo, Yong Sun; Kim, Keon Sik; Song, Kun Woo; Hong, Kwon Pyo; Kang, Young Hwan; Ho, Kwangil

    2004-07-15

    Postirradiation annealing tests were performed to obtain the {sup 133}Xe diffusion coefficients in uranium dioxide (UO{sub 2}) and mixed thorium-uranium dioxide [(Th-U)O{sub 2}] fuels. Specimens were a single-grained UO{sub 2}, a polycrystalline UO{sub 2}, and a polycrystalline (Th-U)O{sub 2}. The (Th-U)O{sub 2} specimen was a mixture of 35% ThO{sub 2} and 65% UO{sub 2}. Each 300-mg specimen was irradiated to a burnup of 0.1 MWd/t U. Postirradiation annealing tests were performed at 1400, 1500, and 1600 deg. C, continuously. The xenon diffusion coefficients for the nearly stoichiometric single-grained UO{sub 2} agree well with the data of others. The xenon diffusion coefficients in the polycrystalline (Th-U)O{sub 2} are approximately one order lower than those in the polycrystalline UO{sub 2}. The xenon diffusion coefficient in the (Th-U)O{sub 2} increases with the increasing oxygen potential of the ambient gas.

  1. Atmospheric Krypton and Xenon Measurements from Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.; Malespin, C. A.; Franz, H.; Manning, H. L.; Trainer, M. G.; Wong, M. H.; Brunner, A.; Atreya, S. K.; Pepin, R. O.; Jones, J. H.; Owen, T. C.; Mahaffy, P. R.

    2013-12-01

    The heavy noble gases krypton and xenon are important tracers of planetary processes from accretion to differentiation and to atmospheric escape. Their abundance and stable isotopic ratios are also indicative of sources as well. The Sample Analysis at Mars (SAM) investigation on the Curiosity rover has measured the Martian atmosphere and reported on the volume mixing ratio of its major constituents (Mahaffy et al., 2013). Here we report the abundance and isotopic ratios of Kr and Xe in the atmosphere of Mars as obtained by semi-static operation of the SAM quadrupole mass spectrometer. Viking provided the first in situ detection of these gases (Owen et al, 1977), suggesting upper limits of 300 ppb for Kr and 80 ppb for Xe, based upon calibration gases with terrestrial isotopic abundances. The abundances of individual isotopes as well as their ratios to one another have been derived from martian meteorite samples by many investigators (e.g., Becker & Pepin, 1984; Bogard & Garrison, 1998). The SAM heavy noble gas data complement the argon isotopic data reported in Mahaffy et al., 2013. Becker, R. H., & Pepin, R. O. (1984). The case for a Martian origin of the shergottites: Nitrogen and noble gases in EETA 79001. Earth and Planetary Science Letters, 69(2), 225-242. Bogard, D. D., & Garrison, D. H. (1998). Relative abundances of argon, krypton, and xenon in the Martian atmosphere as measured in Martian meteorites. Geochimica et cosmochimica acta, 62(10), 1829-1835. Mahaffy, et al., (2013) Abundance and isotopic composition of gases in the martian atmosphere from the Curiosity rover. Science 341, 263-266 Owen, T. et al.,(1977). The composition of the atmosphere at the surface of Mars. Journal of Geophysical research, 82(28), 4635-4639.

  2. Steady-state temperature distribution within a Brayton rotating unit operating in a power conversion system using helium-xenon gas

    NASA Technical Reports Server (NTRS)

    Johnsen, R. L.; Namkoong, D.; Edkin, R. A.

    1971-01-01

    The Brayton rotating unit (BRU), consisting of a turbine, an alternator, and a compressor, was tested as part of a Brayton cycle power conversion system over a side range of steady state operating conditions. The working fluid in the system was a mixture of helium-xenon gases. Turbine inlet temperature was varied from 1200 to 1600 F, compressor inlet temperature from 60 to 120 F, compressor discharge pressure from 20 to 45 psia, rotative speed from 32 400 to 39 600 rpm, and alternator liquid-coolant flow rate from 0.01 to 0.27 pound per second. Test results indicated that the BRU internal temperatures were highly sensitive to alternator coolant flow below the design value of 0.12 pound per second but much less so at higher values. The armature winding temperature was not influenced significantly by turbine inlet temperature, but was sensitive, up to 20 F per kVA alternator output, to varying alternator output. When only the rotational speed was changed (+ or - 10% of rated value), the BRU internal temperatures varied directly with the speed.

  3. Xenon improves neurological outcome and reduces secondary injury following trauma in an in vivo model of traumatic brain injury

    PubMed Central

    Luh, Clara; Gruss, Marco; Radyushkin, Konstantin; Hirnet, Tobias; Werner, Christian; Engelhard, Kristin; Franks, Nicholas P; Thal, Serge C; Dickinson, Robert

    2015-01-01

    Objectives To determine the neuroprotective efficacy of the inert gas xenon following traumatic brain injury, and to determine whether application of xenon has a clinically relevant therapeutic time window. Design Controlled animal study. Setting University research laboratory. Subjects Male C57BL/6N mice (n=196) Interventions 75% xenon, 50% xenon or 30% xenon, with 25% oxygen (balance nitrogen) treatment following mechanical brain lesion by controlled cortical impact. Measurements & Main Results Outcome following trauma was measured using: 1) functional neurological outcome score, 2) histological measurement of contusion volume, 3) analysis of locomotor function and gait. Our study shows that xenon-treatment improves outcome following traumatic brain injury. Neurological outcome scores were significantly (p<0.05) better in xenon-treated groups in the early phase (24 hours) and up to 4 days after injury. Contusion volume was significantly (p<0.05) reduced in the xenon-treated groups. Xenon treatment significantly (p<0.05) reduced contusion volume when xenon was given 15 minutes after injury or when treatment was delayed 1 hour or 3 hours after injury. Neurological outcome was significantly (p<0.05) improved when xenon treatment was given 15 minutes or 1 hour after injury. Improvements in locomotor function (p<0.05) were observed in the xenon-treated group, 1 month after trauma. Conclusions These results show for the first time that xenon improves neurological outcome and reduces contusion volume following traumatic brain injury in mice. In this model, xenon application has a therapeutic time window of up to at least 3 hours. These findings support the idea that xenon may be of benefit as a neuroprotective treatment in brain trauma patients. PMID:25188549

  4. XENON in medical area: emphasis on neuroprotection in hypoxia and anesthesia

    PubMed Central

    2013-01-01

    Xenon is a medical gas capable of establishing neuroprotection, inducing anesthesia as well as serving in modern laser technology and nuclear medicine as a contrast agent. In spite of its high cost, its lack of side effects, safe cardiovascular and organoprotective profile and effective neuroprotective role after hypoxic-ischemic injury (HI) favor its applications in clinics. Xenon performs its anesthetic and neuroprotective functions through binding to glycine site of glutamatergic N-methyl-D-aspartate (NMDA) receptor competitively and blocking it. This blockage inhibits the overstimulation of NMDA receptors, thus preventing their following downstream calcium accumulating cascades. Xenon is also used in combination therapies together with hypothermia or sevoflurane. The neuroprotective effects of xenon and hypothermia cooperate synergistically whether they are applied synchronously or asynchronously. Distinguishing properties of Xenon promise for innovations in medical gas field once further studies are fulfilled and Xenon’s high cost is overcome. PMID:23369273

  5. Chondritic xenon in the Earth's mantle.

    PubMed

    Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G; Füri, Evelyn; Marty, Bernard

    2016-05-05

    Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth's mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth's mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth's accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion.

  6. Solubilities of krypton and xenon in dichlorodifluoromethane

    SciTech Connect

    Shaffer, J.H.; Shockley, W.E.; Greene, C.W.

    1984-07-01

    The solubility behavior of krypton and xenon in dichlorodifluoromethane was investigated for the Consolidated Fuel Reprocessing Program (CFRP) in support of the fluorocarbon absorption process. The solubility data derived from solute radioisotopes had uncertainties of approx. 0.1%. Values for Henry's law constants were initially determined under equilibrium conditions at infinite solute dilution. Based on these results, the study was extended to finite solute concentrations. Nonidealities in the two binary systems were expressed as gas phase fugacity coefficients for each solute at 10/sup 0/ intervals over the range -30 to +50/sup 0/C. 22 references, 4 figures, 2 tables.

  7. Chemically Stable Covalent Organic Framework (COF)-Polybenzimidazole Hybrid Membranes: Enhanced Gas Separation through Pore Modulation.

    PubMed

    Biswal, Bishnu P; Chaudhari, Harshal D; Banerjee, Rahul; Kharul, Ulhas K

    2016-03-24

    Highly flexible, TpPa-1@PBI-BuI and TpBD@PBI-BuI hybrid membranes based on chemically stable covalent organic frameworks (COFs) could be obtained with the polymer. The loading obtained was substantially higher (50 %) than generally observed with MOFs. These hybrid membranes show an exciting enhancement in permeability (about sevenfold) with appreciable separation factors for CO2/N2 and CO2/CH4. Further, we found that with COF pore modulation, the gas permeability can be systematically enhanced.

  8. Stable isotopes of carbon dioxide in soil gas over massive sulfide mineralization at Crandon, Wisconsin

    USGS Publications Warehouse

    Alpers, C.N.; Dettman, D.L.; Lohmann, K.C.; Brabec, D.

    1990-01-01

    Stable isotope ratios of oxygen and carbon were determined for CO2 in soil gas in the vicinity of the massive sulfide deposit at Crandon, Wisconsin with the objective of determining the source of anomalously high CO2 concentrations detected previously by McCarthy et al. (1986). Values of ??13C in soil gas CO2 from depths between 0.5 and 1.0 m were found to range from -12.68??? to -20.03??? (PDB). Organic carbon from the uppermost meter of soil has ??13C between -24.1 and -25.8??? (PDB), indicating derivation from plant species with the C3 (Calvin) type of photosynthetic pathway. Microbial decomposition of the organic carbon and root respiration from C3 and C4 (Hatch-Slack) plants, together with atmospheric CO2 are the likely sources of carbon in soil gas CO2. Values of ??18O in soil-gas CO2 range from 32 to 38??? (SMOW). These ??18O values are intermediate between that calculated for CO2 gas in isotopic equilibrium with local groundwaters and that for atmospheric CO2. The ??18O data indicate that atmospheric CO2 has been incorporated by mixing or diffusion. Any CO2 generated by microbial oxidation of organic matter has equilibrated its oxygen isotopes with the local groundwaters. The isotopic composition of soil-gas CO2 taken from directly above the massive sulfide deposit was not distinguishable from that of background samples taken 1 to 2 km away. No enrichment of the ??13C value of soil-gas CO2 was observed, contrary to what would be expected if the anomalous CO2 were derived from the dissolution of Proterozoic marine limestone country rock or of Paleozoic limestone clasts in glacial till. Therefore, it is inferred that root respiration and decay of C3 plant material were responsible for most CO2 generation both in the vicinity of the massive sulfide and in the "background" area, on the occasion of our sampling. Interpretation of our data is complicated by the effects of rainfall, which significantly reduced the magnitude of the CO2 anomaly. Therefore, we cannot

  9. Solubilized xenon 133 lung scintigraphy

    SciTech Connect

    Oates, E.; Sarno, R.C.

    1988-11-01

    Lung scanning using solubilized xenon 133 can provide important information concerning both pulmonary perfusion and ventilation. This technique proved valuable in establishing the diagnosis of congenital lobar emphysema in a 7-month-old baby.

  10. Experimental Study on Cooling Performance of a Coaxial Pulse Tube Cryocooler for a Liquid Xenon Detector

    NASA Astrophysics Data System (ADS)

    Haruyama, T.; Kasami, K.; Nishitani, T.

    2010-04-01

    An experimental study to improve the cooling power of a coaxial pulse tube cryocooler (PTC) has been carried out. The operating temperature was optimized for cooling liquid xenon at around 165-170 K. The PTC has a coaxial configuration with a cylindrical regenerator inside, a hollow-walled cylindrical pulse tube. The cooling performance obtained was ˜180-200 W at around 165 K, when operated with a 6-6.5 kW GM-type compressor. For the phase shift between pressure and flow, a simple-orifice scheme was used, which resulted in stable operation of a long-term physics experiment. PTCs have now been successfully applied in physics experiments such as MEG and XENON for many years. In order to study flow disturbance inside of a tube, thermometers were placed on an outer cylinder wall to monitor gas temperature inside of a tube. In the original scheme, there is a single gas exhaust line from the pulse tube to an orifice valve and buffer tank. In this study, an additional exhaust line was used to suppress the flow disturbance in such a pulse tube. Also, the cooling power dependence on the regenerator was experimentally studied by changing the mesh size and the length of the regenerator.

  11. High-pressure xenon detector development at Constellation Technology Corporation

    NASA Astrophysics Data System (ADS)

    Austin, Robert A.; Bastian, Lloyd F.

    2006-08-01

    Xenon-filled ionization detectors, due to their high atomic number fill gas (Z=54), moderate densities (~0.3 g/cm 3-0.5 g/cm 3) and good energy resolution (2%-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and Germanium detectors. Until recently, difficulties with obtaining sufficient Xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990's, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Here we will discuss our development of a mobile, large area, spectroscopic array.

  12. Single Ion Trapping for the Enriched Xenon Observatory

    SciTech Connect

    Waldman, Samuel J.; /Stanford U., Phys. Dept. /SLAC

    2006-03-28

    In the last decade, a variety of neutrino oscillation experiments have established that there is a mass difference between neutrino flavors, without determining the absolute neutrino mass scale. The Enriched Xenon Observatory for neutrinoless double beta decay (EXO) will search for the rare decays of xenon to determine the absolute value of the neutrino mass. The experiment uses a novel technique to minimize backgrounds, identifying the decay daughter product in real time using single ion spectroscopy. Here, we describe single ion trapping and spectroscopy compatible with the EXO detector. We extend the technique of single ion trapping in ultrahigh vacuum to trapping in xenon gas. With this technique, EXO will achieve a neutrino mass sensitivity of {approx_equal} .010 eV.

  13. Hyperpolarized Xenon Nuclear Spins Detected by Optical Atomic Magnetometry

    NASA Astrophysics Data System (ADS)

    Yashchuk, V. V.; Granwehr, J.; Kimball, D. F.; Rochester, S. M.; Trabesinger, A. H.; Urban, J. T.; Budker, D.; Pines, A.

    2004-10-01

    We report the use of an atomic magnetometer based on nonlinear magneto-optical rotation with frequency-modulated light to detect nuclear magnetization of xenon gas. The magnetization of a spin-exchange-polarized xenon sample (1.7 c m3 at a pressure of 5bars, natural isotopic abundance, polarization 1% ), prepared remotely to the detection apparatus, is measured with an atomic sensor. An average magnetic field of ˜10 nG induced by the xenon sample on the 10cm diameter atomic sensor is detected with signal-to-noise ratio ˜10 , limited by residual noise in the magnetic environment. The possibility of using modern atomic magnetometers as detectors of nuclear magnetic resonance and in magnetic resonance imaging is discussed. Atomic magnetometers appear to be ideally suited for emerging low-field and remote-detection magnetic resonance applications.

  14. Xenon-related analgesia: a new target for pain treatment.

    PubMed

    Giacalone, Marilù; Abramo, Antonio; Giunta, Francesco; Forfori, Francesco

    2013-07-01

    The noble gas xenon has been known for >50 years in the field of anesthesia with an emerging series of favorable features; several clinical and preclinical studies performed over the last years reveal a renewed interest because they substantially agree on attributing relevant analgesic properties to xenon. The main mechanism of action is the inhibition of N-methyl-D-aspartate receptors of glutamate; it involves the blocking of painful stimuli transmissions from peripheral tissues to the brain and it also avoids the development of pain hypersensitivity. Therefore, this mechanism is responsible for the inhibition of pain transmission at spinal and supraspinal levels, as well as the cortical level. In all these levels of pain pathways, as the development of hyperalgesia is possible, xenon efficacy can also be based on the blocking of these processes. Several forms of pain share such mechanisms in their maintenance, and xenon can be successfully used at low dosages, which have no effects on vital parameters. The literature shows that analgesic features could also emerge outside the field of anesthesia; thus, this could permit xenon to have a larger usage according to local availability.

  15. Hugoniot measurements of double-shocked precompressed dense xenon plasmas.

    PubMed

    Zheng, J; Chen, Q F; Gu, Y J; Chen, Z Y

    2012-12-01

    The current partially ionized plasmas models for xenon show substantial differences since the description of pressure and thermal ionization region becomes a formidable task, prompting the need for an improved understanding of dense xenon plasmas behavior at above 100 GPa. We performed double-shock compression experiments on dense xenon to determine accurately the Hugoniot up to 172 GPa using a time-resolved optical radiation method. The planar strong shock wave was produced using a flyer plate impactor accelerated up to ∼6 km/s with a two-stage light-gas gun. The time-resolved optical radiation histories were acquired by using a multiwavelength channel optical transience radiance pyrometer. Shock velocity was measured and mass velocity was determined by the impedance-matching methods. The experimental equation of state of dense xenon plasmas are compared with the self-consistent fluid variational calculations of dense xenon in the region of partial ionization over a wide range of pressures and temperatures.

  16. In vivo detection of cucurbit[6]uril, a hyperpolarized xenon contrast agent for a xenon magnetic resonance imaging biosensor

    NASA Astrophysics Data System (ADS)

    Hane, Francis T.; Li, Tao; Smylie, Peter; Pellizzari, Raiili M.; Plata, Jennifer A.; Deboef, Brenton; Albert, Mitchell S.

    2017-01-01

    The Hyperpolarized gas Chemical Exchange Saturation Transfer (HyperCEST) Magnetic Resonance (MR) technique has the potential to increase the sensitivity of a hyperpolarized xenon-129 MRI contrast agent. Signal enhancement is accomplished by selectively depolarizing the xenon within a cage molecule which, upon exchange, reduces the signal in the dissolved phase pool. Herein we demonstrate the in vivo detection of the cucurbit[6]uril (CB6) contrast agent within the vasculature of a living rat. Our work may be used as a stepping stone towards using the HyperCEST technique as a molecular imaging modality.

  17. In vivo detection of cucurbit[6]uril, a hyperpolarized xenon contrast agent for a xenon magnetic resonance imaging biosensor

    PubMed Central

    Hane, Francis T.; Li, Tao; Smylie, Peter; Pellizzari, Raiili M.; Plata, Jennifer A.; DeBoef, Brenton; Albert, Mitchell S.

    2017-01-01

    The Hyperpolarized gas Chemical Exchange Saturation Transfer (HyperCEST) Magnetic Resonance (MR) technique has the potential to increase the sensitivity of a hyperpolarized xenon-129 MRI contrast agent. Signal enhancement is accomplished by selectively depolarizing the xenon within a cage molecule which, upon exchange, reduces the signal in the dissolved phase pool. Herein we demonstrate the in vivo detection of the cucurbit[6]uril (CB6) contrast agent within the vasculature of a living rat. Our work may be used as a stepping stone towards using the HyperCEST technique as a molecular imaging modality. PMID:28106110

  18. Isolation and derivatization of plasma taurine for stable isotope analysis by gas chromatography-mass spectrometry

    SciTech Connect

    Irving, C.S.; Klein, P.D.

    1980-09-01

    A method for the isolation and derivatization of plasma taurine is described that allows stable isotope determinations of taurine to be made by gas chromatography-mass spectrometry. The isolation procedure can be applied to 0.1 ml of plasma; the recovery of plasma taurine was 70 to 80%. For gc separation, taurine was converted to its dimethylaminomethylene methyl ester derivative which could not be detected by hydrogen flame ionization, but could be monitored readily by NH/sub 3/ chemical ionization mass spectrometry. The derivatization reaction occurred partially on-column and required optimization of injection conditions. Using stable isotope ratiometry multiple ion detection, (M + 2 + H)/sup +//(M + H)/sup +/ ion ratio of natural abundance taurine was determined with a standard deviation of less than +-0.07% of the ratio. The (1,2-/sup 13/C)taurine/taurine mole ratios of standard mixtures could be accurately determined to 0.001. This stable isotope gc-ms method is suitable for studying the plasma kinetics of (1,2-/sup 13/C)taurine in infants who are at risk with respect to taurine depletion.

  19. The XENON1T Dark Matter Experiment

    NASA Astrophysics Data System (ADS)

    de Perio, Patrick; Xenon Collaboration

    2017-01-01

    Recent results and status of the XENON1T direct dark matter detector will be presented. XENON1T is a two-phase xenon TPC using 248 low radioactivity PMTs to detect scintillation signals in a 2-ton active liquid xenon target. The detector has been fully operational at the Laboratori Nazionale del Gran Sasso since May 2016, with continuously improving xenon purity and reduction of the internal Kr-85 background source. This talk will summarize the detector performance, calibration, and background studies, discussed in more detail in the following XENON1T talks, which are paving the way towards the world's most sensitive dark matter search.

  20. Direct Dark Matter Search with the XENON100 Experiment

    NASA Astrophysics Data System (ADS)

    Mei, Yuan

    Dark matter, a non-luminous, non-baryonic matter, is thought to constitute 23 % of the matter-energy components in the universe today. Except for its gravitational effects, the existence of dark matter has never been confirmed by any other means and its nature remains unknown. If a hypothetical Weakly Interacting Massive Particle (WIMP) were in thermal equilibrium in the early universe, it could have a relic abundance close to that of dark matter today, which provides a promising particle candidate of dark matter. Minimal Super-Symmetric extensions to the standard model predicts a stable particle with mass in the range 10 GeV/c2 to 1000 GeV/c2, and spin-independent cross-section with ordinary matter nucleon sigmax < 1 x 10--43 cm2. The XENON100 experiment deploys a Dual Phase Liquid Xenon Time Projection Chamber (LXeTPC) of 62 kg liquid xenon as its sensitive volume, to detect scintillation (S1) and ionization (S2) signals from WIMP dark matter particles directly scattering off xenon nuclei. The detector is located underground at Laboratori Nazionali del Gran Sasso (LNGS) in central Italy. 1.4 km of rock (3.7 km water equivalent) reduces the cosmic muon background by a factor of 106. The event-by-event 3D positioning capability of TPC allows volume fiducialization. With the self-shielding power of liquid xenon, as well as a 99 kg liquid xenon active veto, the electromagnetic radiation background is greatly suppressed. By utilizing the difference of (S2/S1) between electronic recoil and nuclear recoil, the expected WIMP signature, a small nuclear recoil energy deposition, could be discriminated from electronic recoil background with high efficiency. XENON100 achieved the lowest background rate (< 2.2 x 10--2 events/kg/day/keV) in the dark matter search region (< 40 keV) among all direct dark matter detectors. With 11.2 days of data, XENON100 already sets the world's best spin-independent WIMP-nucleon cross-section limit of 2.7 x 10--44 cm2 at WIMP mass 50 GeV/c 2

  1. Low-power catalytic gas sensing using highly stable silicon carbide microheaters

    NASA Astrophysics Data System (ADS)

    Harley-Trochimczyk, Anna; Rao, Ameya; Long, Hu; Zettl, Alex; Carraro, Carlo; Maboudian, Roya

    2017-04-01

    A robust silicon carbide (SiC) microheater is used for stable low-power catalytic gas sensing at high operating temperatures, where previously developed low-power polycrystalline silicon (polysilicon) microheaters are unstable. The silicon carbide microheater has low power consumption (20 mW to reach 500 °C) and exhibits an order of magnitude lower resistance drift than the polysilicon microheater after continuously heating at 500 °C for 100 h and during temperature increases up to 650 °C. With the deposition of platinum nanoparticle-loaded boron nitride aerogel, the SiC microheater-based catalytic gas sensor detects propane with excellent long-term stability while exhibiting fast response and recovery time (~1 s). The sensitivity is not affected by humidity, nor during 10% duty cycling, which yields a power consumption of only 2 mW with frequent data collection (every 2 s). With a simple change of heater material from silicon to SiC, the microheater and resulting catalytic gas sensor element show significant performance improvement.

  2. Gas-Phase Structure Determination of Dihydroxycarbene, One of the Smallest Stable Singlet Carbenes

    NASA Astrophysics Data System (ADS)

    Womack, Carrie; Crabtree, Kyle N.; McCaslin, Laura; Martinez, Oscar, Jr.; Field, Robert W.; Stanton, John F.; McCarthy, Michael C.

    2014-06-01

    Carbenes (R1-C-R2) are a reactive class of compounds, usually characterized by an electron-deficient divalent carbon atom, found in applications ranging from organic synthesis to gas phase oxidation chemistry. Carbenes with 2- or 3-atom substituents often undergo rapid unimolecular isomerization, but may be stabilized if these substituents are electron-donating. Dihydroxycarbene (HO-C-OH) is one of the smallest singlet carbenes to be afforded this stability, due to its two electron-donating hydroxyl groups. We report the first gas-phase detection and structural characterization of this reactive species, using a combination of Fourier transform microwave spectroscopy and high level electronic structure calculations. Detection in the gas phase indicates that it is fairly stable relative to its isomers, formic acid (HCOOH) and the simplest Criegee intermediate (CH_2OO), the latter of which has recently received a great deal of attention for its role in the atmospheric ozonolysis of alkenes. Our experimental results yield a precise structure of HO-C-OH, and we comment on upcoming experiments investigating its stability and reactivity with other common atmospheric species.

  3. Development of a functionalized Xenon biosensor

    SciTech Connect

    Spence, Megan M.; Ruiz, E. Janette; Rubin, Seth M.; Lowery, Thomas J.; Winssinger, Nicolas; Schultz, Peter G.; Wemmer, David E.; Pines, Alexander

    2004-03-25

    NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon chemical shift, which is a key requirement for being able to multiplex the biosensor.

  4. Xenon preconditioning: the role of prosurvival signaling, mitochondrial permeability transition and bioenergetics in rats.

    PubMed

    Mio, Yasushi; Shim, Yon Hee; Richards, Ebony; Bosnjak, Zeljko J; Pagel, Paul S; Bienengraeber, Martin

    2009-03-01

    Similar to volatile anesthetics, the anesthetic noble gas xenon protects the heart from ischemia/reperfusion injury, but the mechanisms responsible for this phenomenon are not fully understood. We tested the hypothesis that xenon-induced cardioprotection is mediated by prosurvival signaling kinases that target mitochondria. Male Wistar rats instrumented for hemodynamic measurements were subjected to a 30 min left anterior descending coronary artery occlusion and 2 h reperfusion. Rats were randomly assigned to receive 70% nitrogen/30% oxygen (control) or three 5-min cycles of 70% xenon/30% oxygen interspersed with the oxygen/nitrogen mixture administered for 5 min followed by a 15 min memory period. Myocardial infarct size was measured using triphenyltetrazolium staining. Additional hearts from control and xenon-pretreated rats were excised for Western blotting of Akt and glycogen synthase kinase 3 beta (GSK-3beta) phosphorylation and isolation of mitochondria. Mitochondrial oxygen consumption before and after hypoxia/reoxygenation and mitochondrial permeability transition pore opening were determined. Xenon significantly (P < 0.05) reduced myocardial infarct size compared with control (32 +/- 4 and 59% +/- 4% of the left ventricular area at risk; mean +/- sd) and enhanced phosphorylation of Akt and GSK-3beta. Xenon pretreatment preserved state 3 respiration of isolated mitochondria compared with the results obtained in the absence of the gas. The Ca(2+) concentration required to induce mitochondrial membrane depolarization was larger in the presence compared with the absence of xenon pretreatment (78 +/- 17 and 56 +/- 17 microM, respectively). The phosphoinositol-3-kinase-kinase inhibitor wortmannin blocked the effect of xenon on infarct size and respiration. These results indicate that xenon preconditioning reduces myocardial infarct size, phosphorylates Akt, and GSK-3beta, preserves mitochondrial function, and inhibits Ca(2+)-induced mitochondrial permeability

  5. Early treatment with xenon protects against the cold ischemia associated with chronic allograft nephropathy in rats.

    PubMed

    Zhao, Hailin; Luo, Xianghong; Zhou, Zhaowei; Liu, Juying; Tralau-Stewart, Catherine; George, Andrew J T; Ma, Daqing

    2014-01-01

    Chronic allograft nephropathy (CAN) is a common finding in kidney grafts with functional impairment. Prolonged hypothermic storage-induced ischemia-reperfusion injury is associated with the early onset of CAN. As the noble gas xenon is clinically used as an anesthetic and has renoprotective properties in a rodent model of ischemia-reperfusion injury, we studied whether early treatment with xenon could attenuate CAN associated with prolonged hypothermic storage. Exposure to xenon enhanced the expression of insulin growth factor-1 (IGF-1) and its receptor in human proximal tubular (HK-2) cells, which, in turn, increased cell proliferation. Xenon treatment before or after hypothermia-hypoxia decreased cell apoptosis and cell inflammation after reoxygenation. The xenon-induced HK-2 cell proliferation was abolished by blocking the IGF-1 receptor, mTOR, and HIF-1α individually. In the Fischer-to-Lewis rat allogeneic renal transplantation model, xenon exposure of donors before graft retrieval or recipients after engraftment enhanced tubular cell proliferation and decreased tubular cell death and cell inflammation associated with ischemia-reperfusion injury. Compared with control allografts, xenon treatment significantly suppressed T-cell infiltration and fibrosis, prevented the development of CAN, and improved renal function. Thus, xenon treatment promoted recovery from ischemia-reperfusion injury and reduced susceptibility to the subsequent development of CAN in allografts.

  6. Effects of a Hydrogen Gas Environment on Fatigue Crack Growth of a Stable Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kawamoto, Kyohei; Oda, Yasuji; Noguchi, Hiroshi; Higashida, Kenji

    In order to clarify the effects of a hydrogen gas environment on the fatigue crack growth characteristics of stable austenitic stainless steels, bending fatigue tests were carried out in a hydrogen gas, in a nitrogen gas at 1.0 MPa and in air on a SUS316L using the Japanese Industrial Standards (type 316L). Also, in order to discuss the difference in the hydrogen sensitivity between austenitic stainless steels, the fatigue tests were also carried out on a SUS304 using the Japanese Industrial Standards (type 304) metastable austenitic stainless steel as a material for comparison. The main results obtained are as follows. Hydrogen gas accelerates the fatigue crack growth rate of type 316L. The degree of the fatigue crack growth acceleration is low compared to that in type 304. The fracture surfaces of both the materials practically consist of two parts; the faceted area seemed to be brittle and the remaining area occupying a greater part of the fracture surface and seemed to be ductile. The faceted area does not significantly contribute to the fatigue crack growth rate in both austenitic stainless steels. The slip-off mechanism seems to be valid not only in air and in nitrogen, but also in hydrogen. Also, the main cause of the fatigue crack growth acceleration of both materials occurs by variation of the slip behaviour. The difference in the degree of the acceleration, which in type 316L is lower than in type 304, seems to be caused by the difference in the stability of the γ phase.

  7. Optimization of Dual-Energy Xenon-CT for Quantitative Assessment of Regional Pulmonary Ventilation

    PubMed Central

    Fuld, Matthew K.; Halaweish, Ahmed; Newell, John D.; Krauss, Bernhard; Hoffman, Eric A.

    2013-01-01

    Objective Dual-energy X-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study we seek to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. Materials and Methods The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon-oxygen gas mixtures (0, 20, 25, 33, 50, 66, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved three-material decomposition calibration parameters. Additionally, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine in order to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. Results Attenuation curves for xenon were obtained from the syringe test objects and were used to develop improved three-material decomposition parameters (HU enhancement per percent xenon: Within the chest phantom: 2.25 at 80kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; In open air: 2.5 at 80kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally non-dependent portion of the airway tree test-object, while not affecting quantitation of xenon in the three-material decomposition DECT. 40%Xe

  8. Optimization in multidimensional gas chromatography applying quantitative analysis via a stable isotope dilution assay.

    PubMed

    Schmarr, Hans-Georg; Slabizki, Petra; Legrum, Charlotte

    2013-08-01

    Trace level analyses in complex matrices benefit from heart-cut multidimensional gas chromatographic (MDGC) separations and quantification via a stable isotope dilution assay. Minimization of the potential transfer of co-eluting matrix compounds from the first dimension ((1)D) separation into the second dimension separation requests narrow cut-windows. Knowledge about the nature of the isotope effect in the separation of labeled and unlabeled compounds allows choosing conditions resulting in at best a co-elution situation in the (1)D separation. Since the isotope effect strongly depends on the interactions of the analytes with the stationary phase, an appropriate separation column polarity is mandatory for an isotopic co-elution. With 3-alkyl-2-methoxypyrazines and an ionic liquid stationary phase as an example, optimization of the MDGC method is demonstrated and critical aspects of narrow cut-window definition are discussed.

  9. Development and first results of the Yale PIXeY two-phase xenon detector

    NASA Astrophysics Data System (ADS)

    Destefano, Nicholas E.; Bernard, Ethan; Edwards, Blair; Gai, Moshe; Horn, Markus; Larsen, Nicole; McKinsey, Daniel; Tennyson, Brian; Wahl, Christopher

    2013-09-01

    PIXeY (Particle Identification in Xenon at Yale) is a two-phase (liquid/gas) xenon prototype time projection chamber with 3 kg active mass. PIXeY was built to optimize energy resolution and gamma/neutron discrimination, with a number of technological improvements over previous work. Parallel-wire grids, which control the drift and proportionalscintillation fields, are optimized both for light collection efficiency and field uniformity. High quantum efficiency Hamamatsu R8778 PMTs, high-reflectivity Teflon walls, and charge-light anti-correlation techniques are also incorporated. The first run of the detector has concluded, where all systems were tested both using LED calibration methods as well as using sources for calibration and spectral measurements. Ultimately our results were limited by PMT calibration issues, low light collection caused by saturation, and low drift fields constrained by high voltage hardware. The second run of the detector is currently underway with several improved components. The feedthroughs for higher voltages have improved to allow a much higher operating voltage, new PMT bases for more stable operation have been installed, and three new grids with transparencies between 92% and 97% have been added. Once the energy resolution studies have concluded, PIXeY will serve as a platform for future improvements, including multiple optical volumes and single wire readout for R&D on gamma-ray imaging.

  10. The XENON100 Dark Matter Experiment: Design, Construction, Calibration and 2010 Search Results with Improved Measurement of the Scintillation Response of Liquid Xenon to Low-Energy Nuclear Recoils

    NASA Astrophysics Data System (ADS)

    Plante, Guillaume

    An impressive array of astrophysical observations suggest that 83% of the matter in the universe is in a form of non-luminous, cold, collisionless, non-baryonic dark matter. Several extensions of the Standard Model of particle physics aimed at solving the hierarchy problem predict stable weakly interacting massive particles (WIMPs) that could naturally have the right cosmological relic abundance today to compose most of the dark matter if their interactions with normal matter are on the order of a weak scale cross section. These candidates also have the added benefit that their properties and interaction rates can be computed in a well defined particle physics model. A considerable experimental effort is currently under way to uncover the nature of dark matter. One method of detecting WIMP dark matter is to look for its interactions in terrestrial detectors where it is expected to scatter off nuclei. In 2007, the XENON10 experiment took the lead over the most sensitive direct detection dark matter search in operation, the CDMS II experiment, by probing spin-independent WIMP-nucleon interaction cross sections down to sigmachi N ˜ 5 x 10-44 cm 2 at 30 GeV/c2. Liquefied noble gas detectors are now among the technologies at the forefront of direct detection experiments. Liquid xenon (LXe), in particular, is a well suited target for WIMP direct detection. It is easily scalable to larger target masses, allows discrimination between nuclear recoils and electronic recoils, and has an excellent stopping power to shield against external backgrounds. A particle losing energy in LXe creates both ionization electrons and scintillation light. In a dual-phase LXe time projection chamber (TPC) the ionization electrons are drifted and extracted into the gas phase where they are accelerated to amplify the charge signal into a proportional scintillation signal. These two signals allow the three-dimensional localization of events with millimeter precision and the ability to

  11. [Xenon anaesthesia--clinical characteristics, benefits and disadvantages and fields of application].

    PubMed

    Höcker, Jan; Grünewald, Matthias; Bein, Berthold

    2012-06-01

    The noble gas xenon provides many characteristics of the 'ideal anaesthetic agent'. Xenon offers outstanding haemodynamic stability and rapid emergence from anaesthesia without relevant side effects or toxity. The major limitation for its application in clinical routine is the high price. Recent studies demonstrated additional protective effects against ischaemic injury in particular for the heart and the brain. Therefore, xenon may be beneficial in a subset of high risk patients or operations and may become a meaningful alternative to other anaesthetics in this population.

  12. Isolation and Purification of the Xenon Fraction of 252Cf Spontaneous Fission Products for the Production of Radio Xenon Calibration Standards

    SciTech Connect

    McGrath, Christopher A.

    2015-04-01

    The presence of radioactive xenon isotopes indicates that fission events have occurred, and is used to help enforce the Comprehensive Test Ban Treaty. Idaho National Laboratory (INL) produces 135Xe, 133mXe, 133Xe, and 131mXe standards used for the calibration and testing of collection equipment and analytical techniques used to monitor radio xenon emissions. At INL, xenon is produced and collected as one of several spontaneous fission products from a 252Cf source. Further chromatographic purification of the fission gases ensures the separations of the xenon fraction for selective collection. An explanation of the fission gas collection, separation and purification is presented. Additionally, the range of 135Xe to 133Xe ratio that can be isolated is explained. This is an operational update on the work introduced previously, now that it is in operation and has been recharged with a second 252Cf source.

  13. Detection of brown adipose tissue and thermogenic activity in mice by hyperpolarized xenon MRI

    PubMed Central

    Branca, Rosa Tamara; He, Ting; Zhang, Le; Floyd, Carlos S.; Freeman, Matthew; White, Christian; Burant, Alex

    2014-01-01

    The study of brown adipose tissue (BAT) in human weight regulation has been constrained by the lack of a noninvasive tool for measuring this tissue and its function in vivo. Existing imaging modalities are nonspecific and intrinsically insensitive to the less active, lipid-rich BAT of obese subjects, the target population for BAT studies. We demonstrate noninvasive imaging of BAT in mice by hyperpolarized xenon gas MRI. We detect a greater than 15-fold increase in xenon uptake by BAT during stimulation of BAT thermogenesis, which enables us to acquire background-free maps of the tissue in both lean and obese mouse phenotypes. We also demonstrate in vivo MR thermometry of BAT by hyperpolarized xenon gas. Finally, we use the linear temperature dependence of the chemical shift of xenon dissolved in adipose tissue to directly measure BAT temperature and to track thermogenic activity in vivo. PMID:25453088

  14. Characteristics of a cylindrical collector mirror for laser-produced xenon plasma soft X-rays and improvement of mirror lifetime by buffer gas

    SciTech Connect

    Inoue, Tomoaki; Mochizuki, Takayasu; Miyamoto, Shuji; Masuda, Kazuya; Amano, Sho; Kanda, Kazuhiro

    2012-12-15

    The focusing characteristics of a ruthenium-coated cylindrical mirror were investigated on the basis of its ability to collect and focus broadband 5-17-nm soft X-rays emitted from a laser-produced plasma. Based on the plasmas spectral intensity distribution and the reflectivity function of the mirror, we defined the optimum position of the integrated cylindrical mirror at which the X-ray energy flux transported and focused through the mirror was maximum. A minimum spot diameter of 22 mm at a distance of approximately 200 mm from a soft X-ray source was confirmed. The maximum intensity of the collected soft X-rays was 1.3 mJ/cm{sup 2} at the center of the irradiation zone. Thus, the irradiation intensity was improved by approximately 27 times when compared to that of 47 {mu}J/cm{sup 2} without the mirror. The debris sputtering rate on the reflection surface of the mirror can be reduced to 1/110 by argon gas at 11 Pa, while the attenuation rate of the soft X-rays due to absorption by the buffer gas can be suppressed to less than 10% at the focal point. The focusing property of the mirror is expected to be maintained for 3000 h or longer without significant degradation for a 100 W/320 pps laser shot if the ruthenium layer is thicker than 10 {mu}m. These results suggest that a stand-alone broadband soft X-ray processing system can be realized by using laser-produced plasma soft X-rays.

  15. Characteristics of a cylindrical collector mirror for laser-produced xenon plasma soft X-rays and improvement of mirror lifetime by buffer gas.

    PubMed

    Inoue, Tomoaki; Mochizuki, Takayasu; Miyamoto, Shuji; Masuda, Kazuya; Amano, Sho; Kanda, Kazuhiro

    2012-12-01

    The focusing characteristics of a ruthenium-coated cylindrical mirror were investigated on the basis of its ability to collect and focus broadband 5-17-nm soft X-rays emitted from a laser-produced plasma. Based on the plasmas spectral intensity distribution and the reflectivity function of the mirror, we defined the optimum position of the integrated cylindrical mirror at which the X-ray energy flux transported and focused through the mirror was maximum. A minimum spot diameter of 22 mm at a distance of approximately 200 mm from a soft X-ray source was confirmed. The maximum intensity of the collected soft X-rays was 1.3 mJ/cm(2) at the center of the irradiation zone. Thus, the irradiation intensity was improved by approximately 27 times when compared to that of 47 μJ/cm(2) without the mirror. The debris sputtering rate on the reflection surface of the mirror can be reduced to 1/110 by argon gas at 11 Pa, while the attenuation rate of the soft X-rays due to absorption by the buffer gas can be suppressed to less than 10% at the focal point. The focusing property of the mirror is expected to be maintained for 3000 h or longer without significant degradation for a 100 W/320 pps laser shot if the ruthenium layer is thicker than 10 μm. These results suggest that a stand-alone broadband soft X-ray processing system can be realized by using laser-produced plasma soft X-rays.

  16. A measurement of the relativistic rise in xenon-filled ionisation chambers for cosmic ray iron

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.; Parnell, T. A.

    1980-01-01

    The relativistic rise of ionization in a pair of xenon-filled pulse ion chambers was measured for primary iron nuclei during a recent balloon flight. Energy calibration over the range 21.5-60 GeV/n was made with a Freon-12 gas Cerenkov detector. This allowed a comparison with recent calculations of the relativistic rise in xenon counters and an estimate of the ion chamber resolution above 21.5 GeV/n to be made.

  17. Magnetic Field Strength Dependence of Transverse Relaxation and Signal-to-Noise Ratio for Hyperpolarized Xenon-129 and Helium-3 Gas Magnetic Resonance Imaging of Lungs

    NASA Astrophysics Data System (ADS)

    Dominguez-Viqueira, William

    Magnetic resonance (MR) imaging with hyperpolarized noble gases (HNG), 3He or 129Xe, has become a promising approach for studying lung anatomy and function. Unlike conventional MR imaging, the magnetization in HNG MR is independent of the magnetic field strength. This means that no improvement in signal-to-noise ratio (SNR) is expected with increasing clinical field strength above ˜0.25T. Furthermore, it has been predicted that the SNR may decline at clinical field strength due to decreases in the apparent transverse relaxation time (T2*), caused by the increased magnetic susceptibility induced field gradients at the air-tissue interface. In this thesis the magnetic field strength dependence of T2* and SNR in HNG MR is investigated experimentally in rodent and human lungs. For rodent imaging, a novel broad-band (0.1-100MHz) variable field strength MR imaging system for rodents was built. This system permitted imaging of 129Xe, 3He and 1H at low magnetic field strengths (3-73.5mT) to experimentally investigate the field dependence of HNG imaging SNR in rodent lungs. In vivo 129Xe and 3He signals were acquired at 73.5mT and T 2* was estimated to be approximately 180+/-8 ms, in good agreement with previously reported values. At 73.5mT, image noise is dominated by losses originated from the radiofrequency (RF) coils. To address this issue, RF coils were built using different types of copper wire and compared in phantoms and in vivo in rat lungs using hyperpolarized 3He and 129Xe gas. An SNR improvement of up to 200% was obtained with Litz wire compared to conventional copper wire. This improvement demonstrated the feasibility of HNG lung imaging in rodents at 73.5mT with SNR comparable to that obtained at clinical field strengths. To verify the SNR field dependence in humans, hyperpolarized 3He lung imaging at two commonly used clinical field strengths (1.5T and 3T) was performed in the same volunteers and compared. No significant differences in SNR were obtained

  18. Atmospheric Trace Gas Abundances and Stable Isotope Ratios via IR-LIF

    NASA Technical Reports Server (NTRS)

    Blake, Geoffrey A.

    2004-01-01

    studies form the necessary precursors to the development of compact, lightweight stable isotope/trace gas sensors for future planetary missions.

  19. Xenon hydrate dissociation measurements with model protein systems.

    PubMed

    Booker, Ryan D; Koh, Carolyn A; Sloan, E Dendy; Sum, Amadeu K; Shalaev, Evgenyi; Singh, Satish K

    2011-09-01

    Effective long-term storage remains a significant challenge to the use and development of protein pharmaceuticals. We have investigated the interactions between clathrate hydrates and model protein solutions to determine the effects on hydrate formation. Here, the dissociation curve and equilibrium conditions for xenon clathrate hydrate with model lysozyme and lactate dehydrogenase (LDH) protein solutions have been studied using calorimetry measurements at pressures ranging from 3 to 20 bar. Sucrose in solution was shown to exhibit small inhibition effects on xenon hydrate formation, shifting the dissociation curve and decreasing the conversion of water to hydrate by 15-26%. The addition of l-histidine buffer and lysozyme at low concentrations did not substantially inhibit hydrate formation. However, small shifts in the dissociation curve were demonstrated for solutions containing LDH. The presence of lysozyme and LDH in solution did not significantly alter the conversion of water to hydrate, indicating that these and similar proteins do not substantially affect the extent of xenon gas hydrate formation. Preliminary experiments were performed for LDH solutions to assess the impact of xenon hydrate formation and dissociation on enzymatic activity, with samples stored in hydrate systems showing small decreases in activity.

  20. Terrestrial and Martian weathering signatures of xenon components in shergottite mineral separates

    NASA Astrophysics Data System (ADS)

    Cartwright, J. A.; Ocker, K. D.; Crowther, S. A.; Burgess, R.; Gilmour, J. D.

    2010-08-01

    Xenon-isotopic ratios, step-heating release patterns, and gas concentrations of mineral separates from Martian shergottites Roberts Massif (RBT) 04262, Dar al Gani (DaG) 489, Shergotty, and Elephant Moraine (EET) 79001 lithology B are reported. Concentrations of Martian atmospheric xenon are similar in mineral separates from all meteorites, but more weathered samples contain more terrestrial atmospheric xenon. The distributions of xenon from the Martian and terrestrial atmospheres among minerals in any one sample are similar, suggesting similarities in the processes by which they were acquired. However, in opaque and maskelynite fractions, Martian atmospheric xenon is released at higher temperatures than terrestrial atmospheric xenon. It is suggested that both Martian and terrestrial atmospheric xenon were initially introduced by weathering (low temperature alteration processes). However, the Martian component was redistributed by shock, accounting for its current residence in more retentive sites. The presence or absence of detectable 129Xe from the Martian atmosphere in mafic minerals may correspond to the extent of crustal contamination of the rock's parent melt. Variable contents of excess 129Xe contrast with previously reported consistent concentrations of excess 40Ar, suggesting distinct sources contributed these gases to the parent magma.

  1. Fission Xenon on Mars

    NASA Technical Reports Server (NTRS)

    Mathew, K. J.; Marti, K.; Marty, B.

    2002-01-01

    Fission Xe components due to Pu-244 decay in the early history of Mars have been identified in nakhlites; as in the case of ALH84001 and Chassigny the fission gas was assimilated into indigenous solar-type Xe. Additional information is contained in the original extended abstract.

  2. Methane and its Stable Isotope Signature Across Pennsylvania: Assessing the Potential Impacts of Natural Gas Development and Agriculture

    NASA Astrophysics Data System (ADS)

    Ramos-Garcés, F.; Fuentes, J. D.; Grannas, A. M.; Martins, D. K.

    2012-12-01

    Methane is an important greenhouse gas with a global warming potential 72 times that of carbon dioxide (20 year time horizon). Many recent efforts have been focused on improving our understanding of methane sources to the atmosphere and better quantifying the atmospheric methane budget. Increased natural gas exploration, particularly associated with shale gas drilling, has been hypothesized to be a potential source of atmospheric methane during well development and also due to fugitive emissions from operational well sites and pipelines. For a six-day period in June 2012, measurements of methane and its stable isotope signature were obtained from a mobile measurement platform using cavity ringdown spectroscopy. Transects from southwestern to northeastern Pennsylvania were studied, with samples obtained in rural, forested, urban, farm-impacted and well-impacted sites. Particular emphasis was placed on performing air sampling in the vicinity of natural gas wells under development, just completed, and in full operation. In the rural atmosphere, away from cattle farms and natural gas systems, the ambient levels of methane were around 1.75 ppm. Near and around gas wells under development, ambient methane levels resembled those found in the rural atmosphere. In some cases, the atmosphere was enriched with methane (up to 2.2 ppm) in areas near old wells and existing pipelines. Ambient methane levels around cattle farms were significantly enhanced, with mixing ratios reaching about 4 ppm. We will discuss here the impact of both gas well development and agricultural activities on observed methane concentrations and stable isotope signatures.

  3. Study of detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance model.

    PubMed

    Jingyi, Zhu

    2015-01-01

    The detecting mechanism of carbon nanotubes gas sensor based on multi-stable stochastic resonance (MSR) model was studied in this paper. A numerically stimulating model based on MSR was established. And gas-ionizing experiment by adding electronic white noise to induce 1.65 MHz periodic component in the carbon nanotubes gas sensor was performed. It was found that the signal-to-noise ratio (SNR) spectrum displayed 2 maximal values, which accorded to the change of the broken-line potential function. The experimental results of gas-ionizing experiment demonstrated that periodic component of 1.65 MHz had multiple MSR phenomena, which was in accordance with the numerical stimulation results. In this way, the numerical stimulation method provides an innovative method for the detecting mechanism research of carbon nanotubes gas sensor.

  4. Quench gases for xenon- (and krypton-) filled proportional counters

    NASA Technical Reports Server (NTRS)

    Ramsey, B. D.; Agrawal, P. C.

    1988-01-01

    Xenon-filled proportional counters are used extensively in astronomy, particularly in the hard X-ray region. The choice of quench gas can have a significant effect on the operating characteristics of the instrument although the data necessary to make the choice are not easily obtainable. Results which detail the performance obtained from both cylindrical and parallel field geometries for a wide variety of readily available, ultrahigh or research grade purity, quench gases are presented.

  5. Xenon as a Neuroprotectant in Traumatic Brain Injury

    DTIC Science & Technology

    2012-03-01

    Device and Dragonfly (model HPD-1700) Variable Pressure Waveform Generator with transducer, charge amplifier, and remote triggering device were...manufactured by Dragonfly and were delivered to Dr. Kristal’s laboratory. 1c. Methods development. Xenon/air delivery. Methods for gas delivery...ridge and fitted with a Leur-loc fitting and the animal is attached to the Dragonfly (model HPD-1700) Variable Pressure Waveform Generator and subjected

  6. Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon: Results of a preliminary study.

    PubMed

    Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

    2017-01-01

    Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected

  7. The haemodynamic and catecholamine response to xenon/remifentanil anaesthesia in Beagle dogs.

    PubMed

    Francis, Roland C E; Reyle-Hahn, Matthias S; Höhne, Claudia; Klein, Adrian; Theruvath, Ilka; Donaubauer, Bernd; Busch, Thilo; Boemke, Willehad

    2008-07-01

    The noble gas xenon seems to have minimal cardiovascular side-effects and so may be an ideal anaesthetic agent when investigating cardiovascular physiology. In comparison with standard modern anaesthetics, we investigated the haemodynamic and hormonal effects of xenon in Beagle dogs. After a 30 min baseline period, anaesthesia was induced with propofol and maintained with either (1) 1.2% isoflurane/70% nitrous oxide (N(2)O), (2) 0.8% isoflurane/0.5 microg/kg/min remifentanil or (3) 63% xenon/0.5 microg/kg/min remifentanil (n = 6 per group). Haemodynamics were recorded and blood samples taken before and 60 min after induction. Mean arterial blood pressure (MAP) was higher in conscious dogs than during isoflurane/N(2)O (86 +/- 2 vs. 65 +/- 2 mmHg, mean +/- SEM) and isoflurane/remifentanil anaesthesia (95 +/- 2 vs. 67 +/- 3 mmHg), whereas MAP did not decrease significantly in response to xenon/remifentanil anaesthesia (96 +/- 4 vs. 85 +/- 6 mmHg). Bradycardia was present during isoflurane/remifentanil (54 +/- 2/min) and xenon/remifentanil (40 +/- 3/min), but not during isoflurane/N(2)O anaesthesia (98 +/- 3/min, P < 0.05). Xenon/remifentanil anaesthesia induced the highest reduction in cardiac output (CO) (-61%), and the highest increase in systemic vascular resistance (+120%) among all treatment groups (P < 0.05). A simultaneous increase in endogenous adrenaline and noradrenaline concentrations could only be observed in the xenon/remifentanil group, whereas angiotensin II and vasopressin concentrations increased in all groups. In conclusion, xenon/remifentanil anaesthesia maintains MAP but reduces heart rate and CO and is associated with a considerable stimulation of vasopressor hormones in Beagle dogs. Therefore, xenon/remifentanil exerts a new quality of adverse haemodynamic effects different from volatile anaesthetics and may not perform better during studies of cardiovascular physiology.

  8. Stable hydrogen isotopic analysis of nanomolar molecular hydrogen by automatic multi-step gas chromatographic separation.

    PubMed

    Komatsu, Daisuke D; Tsunogai, Urumu; Kamimura, Kanae; Konno, Uta; Ishimura, Toyoho; Nakagawa, Fumiko

    2011-11-15

    We have developed a new automated analytical system that employs a continuous flow isotope ratio mass spectrometer to determine the stable hydrogen isotopic composition (δD) of nanomolar quantities of molecular hydrogen (H(2)) in an air sample. This method improves previous methods to attain simpler and lower-cost analyses, especially by avoiding the use of expensive or special devices, such as a Toepler pump, a cryogenic refrigerator, and a special evacuation system to keep the temperature of a coolant under reduced pressure. Instead, the system allows H(2) purification from the air matrix via automatic multi-step gas chromatographic separation using the coolants of both liquid nitrogen (77 K) and liquid nitrogen + ethanol (158 K) under 1 atm pressure. The analytical precision of the δD determination using the developed method was better than 4‰ for >5 nmol injections (250 mL STP for 500 ppbv air sample) and better than 15‰ for 1 nmol injections, regardless of the δD value, within 1 h for one sample analysis. Using the developed system, the δD values of H(2) can be quantified for atmospheric samples as well as samples of representative sources and sinks including those containing small quantities of H(2) , such as H(2) in soil pores or aqueous environments, for which there is currently little δD data available. As an example of such trace H(2) analyses, we report here the isotope fractionations during H(2) uptake by soils in a static chamber. The δD values of H(2) in these H(2)-depleted environments can be useful in constraining the budgets of atmospheric H(2) by applying an isotope mass balance model.

  9. Monitoring xenon purity in the LUX detector with a mass spectrometry system

    NASA Astrophysics Data System (ADS)

    Balajthy, Jon; LUX Experiment Collaboration

    2015-04-01

    The LUX dark matter search experiment is a 350 kg two-phase liquid/gas xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. To monitor for radioactive impurities such as krypton and impurities which limit charge yield such as oxygen, LUX uses a xenon sampling system consisting of a mass spectrometer and a liquid nitrogen cold trap. The cold trap separates the gaseous impurities from a small sample of xenon and allows them to pass to the mass spectrometer for analysis. We report here on results from the LUX xenon sampling program. We also report on methods to enhance the sensitivity of the cold trap technique in preparation for the next-generation LUX-ZEPLIN experiment which will have even more stringent purity requirements.

  10. High Precision Xenon Measurements Reveal the Presence of Solar Xenon in the Mantle Source of Mid Ocean Ridge Basalts

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, S.; Langmuir, C. H.

    2006-12-01

    Xenon isotopes provide unique insights into the sources of volatile material for planet Earth, the degassing of the mantle, and the chemical evolution of the mantle. Whether the Earth's mantle has solar or planetary heavy noble gases has remained a fundamental and outstanding question. Resolving this issue is crucial for planet accretion models and understanding how volatiles were incorporated into the solid Earth. Here we report the detection of solar, or possibly chondritic (Q), xenon in a gas-rich basalt glass. The sample was collected from the Hotu Matua seamount chain, located south of the Sojourn Ridge, during the 2001 Cook16MV expedition. Xenon was extracted by step crushing fresh basalt glass in vacuum, and xenon isotopes were measured using the Nu multicollector noble gas mass spectrometer at Harvard. Based on reproducibility of standards run over a period of 3 days, which were similar in size (3.5 x 10^{-14}cc of ^{130}Xe) to the sample, external precision for ^{124,126}Xe/^{130}Xe ratios are better than 2%, for ^{128}Xe/^{130}Xe is 7‰, and for ^{129}Xe/^{130}Xe and ^{136}Xe/^{130}Xe ratios are 4‰. These uncertainties are only marginally larger than predicted from counting statistics. A clear excess in ^{124,126,128}Xe was observed. The anomalies in non-radiogenic isotopes of xenon cannot result from instrumental mass fractionation or other experimental artifacts since excesses in ^{128}Xe are correlated with excesses in ^{129}Xe. In addition, the ^{129}Xe/^{130}Xe and ^{136}Xe/^{130}Xe ratios fall on the MORB line. Thus, we conclude that the anomalies in the non-radiogenic isotopes of xenon are a real feature of the mantle source of MORBs. Excesses in ^{124,126,128}Xe/^{130}Xe ratios plot on the air solar mixing line and indicate the presence of a solar xenon component in the MORB source. Since the non-radiogenic isotopic composition of solar and Q xenon are similar, a chondritic xenon component cannot be ruled out. Krypton isotopes can potentially

  11. Inhalation anaesthesia: from diethyl ether to xenon.

    PubMed

    Bovill, J G

    2008-01-01

    Modern anaesthesia is said to have began with the successful demonstration of ether anaesthesia by William Morton in October 1846, even though anaesthesia with nitrous oxide had been used in dentistry 2 years before. Anaesthesia with ether, nitrous oxide and chloroform (introduced in 1847) rapidly became commonplace for surgery. Of these, only nitrous oxide remains in use today. All modern volatile anaesthetics, with the exception of halothane (a fluorinated alkane), are halogenated methyl ethyl ethers. Methyl ethyl ethers are more potent, stable and better anaesthetics than diethyl ethers. They all cause myocardial depression, most markedly halothane, while isoflurane and sevoflurane cause minimal cardiovascular depression. The halogenated ethers also depress the normal respiratory response to carbon dioxide and to hypoxia. Other adverse effects include hepatic and renal damage. Hepatitis occurs most frequently with halothane, although rare cases have been reported with the other agents. Liver damage is not caused by the anaesthetics themselves, but by reactive metabolites. Type I hepatitis occurs fairly commonly and takes the form of a minor disturbance of liver enzymes, which usually resolves without treatment. Type II, thought to be immune-mediated, is rare, unpredictable and results in a severe fulminant hepatitis with a high mortality. Renal damage is rare, and was most often associated with methoxyflurane because of excessive plasma fluoride concentrations resulting from its metabolism. Methoxyflurane was withdrawn from the market because of the high incidence of nephrotoxicity. Among the contemporary anaesthetics, the highest fluoride concentrations have been reported with sevoflurane, but there are no reports of renal dysfunction associated with its use. Recently there has been a renewed interest in xenon, one of the noble gases. Xenon has many of the properties of an ideal anaesthetic. The major factor limiting its more widespread is the high cost, about

  12. Heat capacity of xenon adsorbed on nanobundle grooves

    NASA Astrophysics Data System (ADS)

    Chishko, K. A.; Sokolova, E. S.

    2016-02-01

    A model of a one-dimensional nonideal gas in an external transverse force field is used to interpret the experimentally observed thermodynamic properties of xenon deposited in grooves on the surface of carbon nanobundles. A nonideal gas model with pairwise interactions is not entirely adequate for describing dense adsorbates (at low temperatures), but makes it easy to account for the exchange of particles between the 1D adsorbate and the 3D atmosphere, which is an important factor at intermediate (on the order of 35 K for xenon) and, especially, high (˜100 K) temperatures. In this paper, we examine a 1D real gas taking only the one-dimensional Lennard-Jones interaction into account, but under exact equilibrium with respect to the number of particles between the 1D adsorbate and the 3D atmosphere of the measurement cell. The low-temperature branch of the specific heat is fitted independently by an elastic chain model so as to obtain the best agreement between theory and experiment over the widest possible region, beginning at zero temperature. The gas approximation sets in after temperatures for which the phonon specific heat of the chain essentially transforms to a one-dimensional equipartition law. Here the basic parameters of both models can be chosen so that the heat capacity C(T) of the chain transforms essentially continuously into the corresponding curve for the gas approximation. Thus, it can be expected that an adequate interpretation of the real temperature dependences of the specific heat of low-dimensionality atomic adsorbates can be obtained through a reasonable combination of the phonon and gas approximations. The main parameters of the gas approximation (such as the desorption energy) obtained by fitting the theory to experiments on the specific heat of xenon correlate well with published data.

  13. Hydrogen stable isotopic constraints on methane emissions from oil and gas extraction in the Colorado Front Range, USA

    NASA Astrophysics Data System (ADS)

    Townsend-Small, A.; Botner, E. C.; Jimenez, K.; Blake, N. J.; Schroeder, J.; Meinardi, S.; Barletta, B.; Simpson, I. J.; Blake, D. R.; Flocke, F. M.; Pfister, G.; Bon, D.; Crawford, J. H.

    2015-12-01

    The climatic implications of a shift from oil and coal to natural gas depend on the magnitude of fugitive emissions of methane from the natural gas supply chain. Attempts to constrain methane emissions from natural gas production regions can be confounded by other sources of methane. Here we demonstrate the utility of stable isotopes, particularly hydrogen isotopes, for source apportionment of methane emissions. The Denver, Colorado area is home to a large oil and gas field with both conventional oil and gas wells and newer hydraulic fracturing wells. The region also has a large metropolitan area with several landfills and a sizable cattle population. As part of the DISCOVER-AQ and FRAPPE field campaigns in summer 2014, we collected three types of canister samples for analysis of stable isotopic composition of methane: 1), samples from methane sources; 2), samples from two stationary ground sites, one in the Denver foothills, and one in an oil and gas field; and 3), from the NCAR C-130 aircraft in samples upwind and downwind of the region. Our results indicate that hydrogen isotope ratios are excellent tracers of sources of methane in the region, as we have shown previously in California and Texas. Use of carbon isotope ratios is complicated by the similarity of natural gas isotope ratios to that of background methane. Our results indicate that, despite the large amount of natural gas production in the region, biological sources such as cattle feedlots and landfills account for at least 50% of total methane emissions in the Front Range. Future work includes comparison of isotopes and alkane ratios as tracers of methane sources, and calculation of total methane fluxes in the region using continuous measurements of methane concentrations during aircraft flights.

  14. Hyperpolarized Xenon for NMR and MRI Applications

    PubMed Central

    Witte, Christopher; Kunth, Martin; Döpfert, Jörg; Rossella, Federica; Schröder, Leif

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2. Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method. The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode. PMID:22986346

  15. Crystallographic studies with xenon and nitrous oxide provide evidence for protein-dependent processes in the mechanisms of general anesthesia.

    PubMed

    Abraini, Jacques H; Marassio, Guillaume; David, Helene N; Vallone, Beatrice; Prangé, Thierry; Colloc'h, Nathalie

    2014-11-01

    The mechanisms by which general anesthetics, including xenon and nitrous oxide, act are only beginning to be discovered. However, structural approaches revealed weak but specific protein-gas interactions. To improve knowledge, we performed x-ray crystallography studies under xenon and nitrous oxide pressure in a series of 10 binding sites within four proteins. Whatever the pressure, we show (1) hydrophobicity of the gas binding sites has a screening effect on xenon and nitrous oxide binding, with a threshold value of 83% beyond which and below which xenon and nitrous oxide, respectively, binds to their sites preferentially compared to each other; (2) xenon and nitrous oxide occupancies are significantly correlated respectively to the product and the ratio of hydrophobicity by volume, indicating that hydrophobicity and volume are binding parameters that complement and oppose each other's effects; and (3) the ratio of occupancy of xenon to nitrous oxide is significantly correlated to hydrophobicity of their binding sites. These data demonstrate that xenon and nitrous oxide obey different binding mechanisms, a finding that argues against all unitary hypotheses of narcosis and anesthesia, and indicate that the Meyer-Overton rule of a high correlation between anesthetic potency and solubility in lipids of general anesthetics is often overinterpreted. This study provides evidence that the mechanisms of gas binding to proteins and therefore of general anesthesia should be considered as the result of a fully reversible interaction between a drug ligand and a receptor as this occurs in classical pharmacology.

  16. Ventilation imaging of the paranasal sinuses using xenon-enhanced dynamic single-energy CT and dual-energy CT: a feasibility study in a nasal cast.

    PubMed

    Thieme, Sven F; Möller, Winfried; Becker, Sven; Schuschnig, Uwe; Eickelberg, Oliver; Helck, Andreas D; Reiser, Maximilian F; Johnson, Thorsten R C

    2012-10-01

    To show the feasibility of dual-energy CT (DECT) and dynamic CT for ventilation imaging of the paranasal sinuses in a nasal cast. In a first trial, xenon gas was administered to a nasal cast with a laminar flow of 7 L/min. Dynamic CT acquisitions of the nasal cavity and the sinuses were performed. This procedure was repeated with pulsating xenon flow. Local xenon concentrations in the different compartments of the model were determined on the basis of the enhancement levels. In a second trial, DECT measurements were performed both during laminar and pulsating xenon administration and the xenon concentrations were quantified directly. Neither with dynamic CT nor DECT could xenon-related enhancement be detected in the sinuses during laminar airflow. Using pulsating flow, dynamic imaging showed a xenon wash-in and wash-out in the sinuses that followed a mono-exponential function with time constants of a few seconds. Accordingly, DECT revealed xenon enhancement in the sinuses only after pulsating xenon administration. The feasibility of xenon-enhanced DECT for ventilation imaging was proven in a nasal cast. The superiority of pulsating gas flow for the administration of gas or aerosolised drugs to the paranasal sinuses was demonstrated. • Ventilation of the paranasal sinuses is poorly understood. • Dual-energy CT ventilation imaging has been explored using phantom simulation. • Xenon can be seen in the paranasal sinuses using pulsating xenon flow. • Dual-energy CT uses a lower radiation dose compared with dynamic ventilation CT.

  17. Low-Temperature Photochemically Activated Amorphous Indium-Gallium-Zinc Oxide for Highly Stable Room-Temperature Gas Sensors.

    PubMed

    Jaisutti, Rawat; Kim, Jaeyoung; Park, Sung Kyu; Kim, Yong-Hoon

    2016-08-10

    We report on highly stable amorphous indium-gallium-zinc oxide (IGZO) gas sensors for ultraviolet (UV)-activated room-temperature detection of volatile organic compounds (VOCs). The IGZO sensors fabricated by a low-temperature photochemical activation process and exhibiting two orders higher photocurrent compared to conventional zinc oxide sensors, allowed high gas sensitivity against various VOCs even at room temperature. From a systematic analysis, it was found that by increasing the UV intensity, the gas sensitivity, response time, and recovery behavior of an IGZO sensor were strongly enhanced. In particular, under an UV intensity of 30 mW cm(-2), the IGZO sensor exhibited gas sensitivity, response time and recovery time of 37%, 37 and 53 s, respectively, against 750 ppm concentration of acetone gas. Moreover, the IGZO gas sensor had an excellent long-term stability showing around 6% variation in gas sensitivity over 70 days. These results strongly support a conclusion that a low-temperature solution-processed amorphous IGZO film can serve as a good candidate for room-temperature VOCs sensors for emerging wearable electronics.

  18. Temperature range and conditions of stable operation of gas-discharge rare-earth metal vapor lasers

    NASA Astrophysics Data System (ADS)

    Gerasimov, V. A.; Gerasimov, V. V.; Pavlinskiy, A. V.

    2008-08-01

    We have experimentally studied the temperature range and conditions of the stable operation of rare-earth metal (REM) vapor lasers. Gas-discharge tubes made of alumina (Al2O3-GDTs) were used in the experiments. The lasing appears at the temperature when the saturated-vapor pressure of REMs reaches the value of 0.1 Torr and abruptly drops at the melting temperature of corresponding REM under any excitation conditions. The necessity of protecting film of REM aluminates LnnAlmOk and oxides Ln2O3 on the inner surface of Al2O3-GDT for stable operation of these lasers is shown. An explanation of lasing impossibility in vapors of cerium (Ce), praseodymium (Pr), neodymium (Nd), gadolinium (Gd), and terbium (Tb) under gas-discharge excitation is proposed.

  19. Xenon NMR measurements of permeability and tortuosity in reservoir rocks.

    PubMed

    Wang, Ruopeng; Pavlin, Tina; Rosen, Matthew Scott; Mair, Ross William; Cory, David G; Walsworth, Ronald Lee

    2005-02-01

    In this work we present measurements of permeability, effective porosity and tortuosity on a variety of rock samples using NMR/MRI of thermal and laser-polarized gas. Permeability and effective porosity are measured simultaneously using MRI to monitor the inflow of laser-polarized xenon into the rock core. Tortuosity is determined from measurements of the time-dependent diffusion coefficient using thermal xenon in sealed samples. The initial results from a limited number of rocks indicate inverse correlations between tortuosity and both effective porosity and permeability. Further studies to widen the number of types of rocks studied may eventually aid in explaining the poorly understood connection between permeability and tortuosity of rock cores.

  20. Effect of stable and metastable dimers on collision-induced rototranslational spectra: Carbon dioxide - rare gas mixtures

    NASA Astrophysics Data System (ADS)

    Oparin, Daniil V.; Filippov, Nikolai N.; Grigoriev, Ivan M.; Kouzov, Alexander P.

    2017-07-01

    The role of stable and metastable dimers as well as of free collisions in the collision-induced rototranslational absorption by the compressed CO2-Ar and CO2-Xe gas mixtures is elucidated using the classical three-dimensional trajectories method. The contribution from the stable dimers is obtained via Fourier transform of the dipole correlation function. The spectral bandshape due to the unbound trajectories (metastable dimers and free collisions) is calculated as an averaged Fourier spectrum of the collision-induced dipole moment. The mean lifetimes of metastable dimers have been estimated as 3.8 ps for CO2-Ar and 5.9 ps for CO2-Xe pairs. Trajectory computations are complemented by calculations of zero spectral moments using pair distribution functions. The stable and metastable dimer contribution to the zero spectral moment is shown to be comparable with that from free collisions.

  1. Evaluation of carrier agents for hyperpolarized xenon MRI

    NASA Technical Reports Server (NTRS)

    Venkatesh, A. K.; Zhao, L.; Balamore, D.; Jolesz, F. A.; Albert, M. S.

    2000-01-01

    Several biocompatible carrier agents, in which xenon is highly soluble and has a long T(1), were tested, and injected in living rats. These included saline, Intralipid suspension, perfluorocarbon emulsion and (129)Xe gas-filled liposomes. The T(1) of (129)Xe in these compounds ranged from 47 to 116 s. Vascular injection of these carrier agents was tolerated well, encouraging their use for further experiments in live animals. In vivo spectra, obtained from gas-filled liposomes and perfluorocarbon solutions, suggest that these carrier agents have potential for use in angiography and perfusion imaging. Copyright 2000 John Wiley & Sons, Ltd.

  2. Evaluation of carrier agents for hyperpolarized xenon MRI

    NASA Technical Reports Server (NTRS)

    Venkatesh, A. K.; Zhao, L.; Balamore, D.; Jolesz, F. A.; Albert, M. S.

    2000-01-01

    Several biocompatible carrier agents, in which xenon is highly soluble and has a long T(1), were tested, and injected in living rats. These included saline, Intralipid suspension, perfluorocarbon emulsion and (129)Xe gas-filled liposomes. The T(1) of (129)Xe in these compounds ranged from 47 to 116 s. Vascular injection of these carrier agents was tolerated well, encouraging their use for further experiments in live animals. In vivo spectra, obtained from gas-filled liposomes and perfluorocarbon solutions, suggest that these carrier agents have potential for use in angiography and perfusion imaging. Copyright 2000 John Wiley & Sons, Ltd.

  3. Neuroprotection against traumatic brain injury by xenon, but not argon, is mediated by inhibition at the N-methyl-D-aspartate receptor glycine site.

    PubMed

    Harris, Katie; Armstrong, Scott P; Campos-Pires, Rita; Kiru, Louise; Franks, Nicholas P; Dickinson, Robert

    2013-11-01

    Xenon, the inert anesthetic gas, is neuroprotective in models of brain injury. The authors investigate the neuroprotective mechanisms of the inert gases such as xenon, argon, krypton, neon, and helium in an in vitro model of traumatic brain injury. The authors use an in vitro model using mouse organotypic hippocampal brain slices, subjected to a focal mechanical trauma, with injury quantified by propidium iodide fluorescence. Patch clamp electrophysiology is used to investigate the effect of the inert gases on N-methyl-D-aspartate receptors and TREK-1 channels, two molecular targets likely to play a role in neuroprotection. Xenon (50%) and, to a lesser extent, argon (50%) are neuroprotective against traumatic injury when applied after injury (xenon 43±1% protection at 72 h after injury [N=104]; argon 30±6% protection [N=44]; mean±SEM). Helium, neon, and krypton are devoid of neuroprotective effect. Xenon (50%) prevents development of secondary injury up to 48 h after trauma. Argon (50%) attenuates secondary injury, but is less effective than xenon (xenon 50±5% reduction in secondary injury at 72 h after injury [N=104]; argon 34±8% reduction [N=44]; mean±SEM). Glycine reverses the neuroprotective effect of xenon, but not argon, consistent with competitive inhibition at the N-methyl-D-aspartate receptor glycine site mediating xenon neuroprotection against traumatic brain injury. Xenon inhibits N-methyl-D-aspartate receptors and activates TREK-1 channels, whereas argon, krypton, neon, and helium have no effect on these ion channels. Xenon neuroprotection against traumatic brain injury can be reversed by increasing the glycine concentration, consistent with inhibition at the N-methyl-D-aspartate receptor glycine site playing a significant role in xenon neuroprotection. Argon and xenon do not act via the same mechanism.

  4. Stable isotope and gas properties of two ice wedges from Cape Mamontov Klyk, Laptev Sea, Northern Siberia

    NASA Astrophysics Data System (ADS)

    Boereboom, T.; Samyn, D.; Meyer, H.; Tison, J.-L.

    2011-12-01

    This paper presents and discusses the texture, fabric and gas properties (contents of total gas, O2, N2, CO2, and CH4) of two ice wedges from Cape Mamontov Klyk, Laptev Sea, Northern Siberia. The two ice wedges display contrasting structures: one being of relatively "clean" ice and the other showing clean ice at its centre as well as debris-rich ice on its sides (referred to as ice-sand wedge). A comparison of gas properties, crystal size, fabrics and stable isotope data (δ18O and δD) allows discriminating between three different facies of ice with specific paleoenvironmental signatures, suggesting different climatic conditions and rates of biological activity. More specifically, total gas content and composition reveal variable intensities of meltwater infiltration and show the impact of biological processes with contrasting contributions from anaerobic and aerobic conditions. Stable isotope data are shown to be valid for discussing changes in paleoenvironmental conditions and/or decipher different sources for the snow feeding into the ice wedges with time. Our data also give support to the previous assumption that the composite ice wedge was formed in Pleistocene and the ice wedge in Holocene times. This study sheds more light on the conditions of ice wedge growth under changing environmental conditions.

  5. Determination of atmospheric concentrations of xenon radioisotopes. Progress report

    SciTech Connect

    Abel, K.H.; Panisko, M.E.; Hensley, W.K.; Bowyer, T.W.; Perkins, R.W.

    1995-07-01

    Determination of radioactive xenon concentrations in the atmosphere over a two year period has been performed as part of a research program to develop real-time measurement capabilities. The initial measurements were made to develop, prove, and validate the authors technical approach, while the longer-term measurements are being undertaken to establish natural background concentrations and variability with time. The results reported were made using noble gas fraction (typically 90% Kr and 10% Xe by weight) gas samples obtained from a commercial air-reduction plant in the northeastern US over a two-year interval beginning in the fall of 1993. The concentrated gas samples were typically obtained during a 6--8 hour interval at the commercial reduction plant and were shipped overnight to their laboratory. Analysis was typically completed approximately 24 hours after sampling. The analytical separation process typically took approximately 6 hours and gamma-ray spectrometric measurements were conducted for intervals ranging from 3 to 16 hours. The technical approach involved removal of potentially interfering radon daughter radionuclides using a molecular sieve at room temperature, followed by cryogenic concentration of noble gases using a chilled ({minus}76 C) activated carbon molecular sieve. During initial measurements both molecular sieve materials were contained in 30 foot x 1/4 inch gas chromatography columns for analytical separations. Krypton was separated from Xenon during the analytical procedure by warming the activated carbon molecular sieve to room temperature after initial noble gas concentration and actively pumping it away. Xenon-133 adsorbed to the activated charcoal molecular sieve was then quantified via its 81 keV gamma-ray using initially a p-type intrinsic germanium detector and later a higher efficiency (64% relative to a 3 inch x 3 inch sodium iodide) n-type intrinsic germanium detector.

  6. Xenon fluoride solutions effective as fluorinating agents

    NASA Technical Reports Server (NTRS)

    Hyman, H. H.; Quarterman, L. A.; Sheft, I.

    1967-01-01

    Solutions of xenon fluorides in anhydrous hydrogen fluoride have few disruptive effects and leave a residue consisting of gaseous xenon, which can be recovered and refluorinated. This mild agent can be used with materials which normally must be fluorinated with fluorine alone at high temperatures.

  7. Inference and analysis of xenon outflow curves under multi-pulse injection in two-dimensional chromatography.

    PubMed

    Shu-Jiang, Liu; Zhan-Ying, Chen; Yin-Zhong, Chang; Shi-Lian, Wang; Qi, Li; Yuan-Qing, Fan

    2013-10-11

    Multidimensional gas chromatography is widely applied to atmospheric xenon monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). To improve the capability for xenon sampling from the atmosphere, sampling techniques have been investigated in detail. The sampling techniques are designed by xenon outflow curves which are influenced by many factors, and the injecting condition is one of the key factors that could influence the xenon outflow curves. In this paper, the xenon outflow curves of single-pulse injection in two-dimensional gas chromatography has been tested and fitted as a function of exponential modified Gaussian distribution. An inference formula of the xenon outflow curve for six-pulse injection is derived, and the inference formula is also tested to compare with its fitting formula of the xenon outflow curve. As a result, the curves of both the one-pulse and six-pulse injections obey the exponential modified Gaussian distribution when the temperature of the activated carbon column's temperature is 26°C and the flow rate of the carrier gas is 35.6mLmin(-1). The retention time of the xenon peak for one-pulse injection is 215min, and the peak width is 138min. For the six-pulse injection, however, the retention time is delayed to 255min, and the peak width broadens to 222min. According to the inferred formula of the xenon outflow curve for the six-pulse injection, the inferred retention time is 243min, the relative deviation of the retention time is 4.7%, and the inferred peak width is 225min, with a relative deviation of 1.3%.

  8. Prospects for Barium Tagging in Gaseous Xenon

    SciTech Connect

    Sinclair, D.; Rollin, E.; Smith, J.; Mommers, A.; Ackerman, N.; Aharmim, B.; Auger, M.; Barbeau, P.S.; Benitez-Medina, C.; Breidenbach, M.; Burenkov, A.; Cook, S.; Coppens, A.; Daniels, T.; DeVoe, R.; Dobi, A.; Dolinski, M.J.; Donato, K.; Fairbank, W., Jr.; Farine, J.; Giroux, G.; /Bern U., LHEP /Carleton U. /Stanford U., Phys. Dept. /Carleton U. /Laurentian U. /Carleton U. /SLAC /Indiana U. /Indiana U., CEEM /Korea U. /Stanford U., Phys. Dept. /SLAC /Alabama U. /Colorado State U. /Stanford U., Phys. Dept. /Alabama U. /SLAC /Stanford U., Phys. Dept. /Alabama U. /Massachusetts U., Amherst /SLAC /Alabama U. /SLAC /Maryland U. /Moscow, ITEP /Stanford U., Phys. Dept. /Maryland U. /Bern U., LHEP /Laurentian U. /SLAC /Maryland U.

    2012-05-03

    Tagging events with the coincident detection of a barium ion would greatly reduce the background for a neutrino-less double beta decay search in xenon. This paper describes progress towards realizing this goal. It outlines a source that can produce large quantities of Ba++ in gas, shows that this can be extracted to vacuum, and demonstrates a mechanism by which the Ba++ can be efficiently converted to Ba+ as required for laser identification. It is clear from this study that electrospray is a convenient mechanism for producing Ba++ is gas at atmospheric pressure. It is likely that the source will perform just as effectively at higher pressures. Even though the source region has water vapour and methanol vapour at the 0.3% level, there is no evidence for molecular formation. The use of TEA offers an effective method to achieve the charge state conversion. The overall design of the ion extraction from high pressure to vacuum is very similar to the scheme proposed for the final detector and this appears to work well although the efficiency is not yet determined.

  9. The protective profile of argon, helium, and xenon in a model of neonatal asphyxia in rats.

    PubMed

    Zhuang, Lei; Yang, Ting; Zhao, Hailin; Fidalgo, António Rei; Vizcaychipi, Marcela P; Sanders, Robert D; Yu, Buwei; Takata, Masao; Johnson, Mark R; Ma, Daqing

    2012-06-01

    Xenon provides neuroprotection in multiple animal models; however, little is known about the other noble gases. The aim of the current study was to compare xenon, argon, and helium neuroprotection in a neonatal asphyxia model in rats. Randomized controlled trial. Laboratory. Seven-day-old postnatal Sprague-Dawley rats. Seventy percent argon, helium, xenon, or nitrogen balanced with oxygen after hypoxic-ischemic brain injury. Control animals undergoing moderate hypoxic-ischemia endured reduced neuronal survival at 7 days with impaired neurologic function at the juvenile age compared with naïve animals. Severe hypoxic-ischemic damage produced a large cerebral infarction in controls. After moderate hypoxic-ischemia, all three noble gases improved cell survival, brain structural integrity, and neurologic function on postnatal day 40 compared with nitrogen. Interestingly, argon improved cell survival to naïve levels, whereas xenon and helium did not. When tested against more severe hypoxic-ischemic injury only, argon and xenon reduced infarct volume. Furthermore, postinjury body weight in moderate insult was lower in the helium-treated group compared with the naïve, control, and other noble gas treatment groups, whereas in the severe injurious setting, it is lower in both control and helium-treated groups than other groups. In the nondirectly injured hemisphere, argon, helium, and xenon increased the expression of Bcl-2, whereas helium and xenon increased Bcl-xL. In addition, Bax expression was enhanced in the control and helium groups. These studies indicate that argon and xenon provide neuroprotection against both moderate and severe hypoxia-ischemic brain injury likely through prosurvival proteins synthesis.

  10. Disentangling xenon components in Nakhla: martian atmosphere, spallation and martian interior^1

    NASA Astrophysics Data System (ADS)

    Gilmour, J. D.; Whitby, J. A.; Turner, G.

    2001-01-01

    A powdered sample of Nakhla was separated into 3 subsamples. One was left otherwise untreated, one was washed in water and one etched with HNO 3 removing 6% of the original mass. We report results of isotopic analysis of xenon released by laser step heating on aliquots of each of these subsamples; some aliquots were neutron irradiated before isotopic analysis (to allow determination of I, Ba and U as daughter xenon isotopes) and some were not. There is evidence that water soluble phases contain both martian atmospheric xenon and a component with low 129Xe/ 132Xe, either martian interior xenon or terrestrial atmosphere. Higher temperature data from unirradiated aliquots of the water and acid treated samples reveal two-component mixing. One is a trapped xenon component with 129Xe/ 132Xe = 2.350 ± 0.026, isotopically identical to the martian atmosphere as measured in shock glass from shergottites. It is associated with leachable iodine, suggesting it is trapped close to grain boundaries. It may be a result of shock incorporation of adsorbed atmospheric gas. The second component is best explained as an intimate mixture of martian interior xenon and spallation xenon. The martian interior component is present at a concentration of ˜10 -12 cm 3 STP g -1 132Xe, around 40 times lower than that observed in Chassigny. Its association with spallation xenon (produced from Ba and light rare earth elements) suggests it is in the feldspathic mesostasis. We propose that it was trapped during crystallisation and reflects the mantle source of the parental magma.

  11. Xenon lighting adjusted to plant requirements

    SciTech Connect

    Koefferlein, M.; Doehring, T.; Payer, H.D.; Seidlitz, H.K.

    1994-12-31

    The high luminous flux and spectral properties of xenon lamps would provide an ideal luminary for plant lighting if not excess IR radiation poses several problems for an application: the required filter systems reduce the irradiance at spectral regions of particular importance for plant development. Most of the economical drawbacks of xenon lamps are related to the difficult handling of that excess IR energy. Furthermore, the temporal variation of the xenon output depending on the oscillations of the applied AC voltage has to be considered for the plant development. However, xenon lamps outperform other lighting systems with respect to spectral stability, immediate response, and maximum luminance. Therefore, despite considerable competition by other lighting techniques, xenon lamps provide a very useful tool for special purposes. In plant lighting however, they seem to play a less important role as other lamp and lighting developments can meet these particular requirements at lower costs.

  12. Xenon Gamma Detector Project Support

    SciTech Connect

    Vanier,P.E.; Forman, L.

    2008-04-01

    This project provided funding of $48,500 for part of one year to support the development of compressed xenon spectrometers at BNL. This report describes upgrades that were made to the existing detector system electronics during that period, as well as subsequent testing with check sources and Special Nuclear Materials. Previous testing of the equipment extended only up to the energy of 1.3 MeV, and did not include a spectrum of Pu-239. The new electronics allowed one-button activation of the high voltage ramp that was previously controlled by manual adjustments. Mechanical relays of the charging circuit were replaced by a tera-ohm resistor chain and an optical switch. The preamplifier and shaping amplifier were replaced by more modern custom designs. We found that the xenon purity had not been degraded since the chamber was filled 10 years earlier. The resulting spectra showed significantly better resolution than sodium iodide spectra, and could be analyzed quite effectively by methods using peak area templates.

  13. High pressure xenon ionization detector

    DOEpatents

    Markey, J.K.

    1989-11-14

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

  14. High pressure xenon ionization detector

    DOEpatents

    Markey, John K.

    1989-01-01

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

  15. High-pressure xenon detector development at Constellation Technology Corporation

    NASA Astrophysics Data System (ADS)

    Austin, Robert A.

    2007-08-01

    Xenon-filled ionization detectors, due to their high atomic number fill gas ( Z=54), moderate densities (˜0.3-0.5 g/cm 3) and good energy resolution (2-4% at 662 keV), fill an important niche between more familiar technologies such as NaI(Tl) scintillators and germanium detectors. Until recently, difficulties with obtaining sufficient xenon purity, reducing microphonic sensitivity, and developing low-noise electronics compatible with small ionization signals have hampered the development of this nuclear detection field. Constellation Technology Corporation, whose experience with xenon detectors goes back to the mid 1990s, has made significant progress in these areas and has developed a commercial line of detectors with active volumes ranging from small (35 g Xe) to large (1400 g Xe). Current applications for Constellation's detectors are principally in the area of defense (Unmanned Aerial Vehicles and Advanced Spectroscopic Portals), but as awareness of this technology grows, it will surely find applications in a much expanded range of fields.

  16. Methane sources in gas hydrate-bearing cold seeps: Evidence from radiocarbon and stable isotopes

    USGS Publications Warehouse

    Pohlman, J.W.; Bauer, J.E.; Canuel, E.A.; Grabowski, K.S.; Knies, D.L.; Mitchell, C.S.; Whiticar, Michael J.; Coffin, R.B.

    2009-01-01

    Fossil methane from the large and dynamic marine gas hydrate reservoir has the potential to influence oceanic and atmospheric carbon pools. However, natural radiocarbon (14C) measurements of gas hydrate methane have been extremely limited, and their use as a source and process indicator has not yet been systematically established. In this study, gas hydrate-bound and dissolved methane recovered from six geologically and geographically distinct high-gas-flux cold seeps was found to be 98 to 100% fossil based on its 14C content. Given this prevalence of fossil methane and the small contribution of gas hydrate (??? 1%) to the present-day atmospheric methane flux, non-fossil contributions of gas hydrate methane to the atmosphere are not likely to be quantitatively significant. This conclusion is consistent with contemporary atmospheric methane budget calculations. In combination with ??13C- and ??D-methane measurements, we also determine the extent to which the low, but detectable, amounts of 14C (~ 1-2% modern carbon, pMC) in methane from two cold seeps might reflect in situ production from near-seafloor sediment organic carbon (SOC). A 14C mass balance approach using fossil methane and 14C-enriched SOC suggests that as much as 8 to 29% of hydrate-associated methane carbon may originate from SOC contained within the upper 6??m of sediment. These findings validate the assumption of a predominantly fossil carbon source for marine gas hydrate, but also indicate that structural gas hydrate from at least certain cold seeps contains a component of methane produced during decomposition of non-fossil organic matter in near-surface sediment.

  17. Observation of a Rosensweig Instability and Stable Quantum Droplets in a Dipolar Bose Gas

    NASA Astrophysics Data System (ADS)

    Pfau, Tilman; Ferrier Barbut, Igor; Kadau, Holger; Schmitt, Matthias; Wenzel, Matthias

    2016-05-01

    Ferrofluids show unusual hydrodynamic effects due to the magnetic nature of their constituents. For increasing magnetization a classical ferrofluid undergoes a Rosensweig instability and creates self-organized ordered surface structures or droplet crystals. We observe a related instability in a Bose-Einstein condensate with strong dipolar interactions resulting in surprisingly stable droplet crystals. We find that quantum fluctuations which are the origin of genuine quantum many-body effects cannot be neglected and provide a stabilizing mechanism. We study experimentally individual stable quantum droplets containing about 800 atoms which are expected to collapse at the mean-field level due to the essentially attractive interaction. By systematic measurements on individual droplets we demonstrate quantitatively that quantum fluctuations stabilize them against the mean-field collapse. We observe in addition interference of several droplets indicating that this stable many-body state is phase coherent.

  18. Gamma background studies for the XENON experiment using a High Purity Germanium Detector

    NASA Astrophysics Data System (ADS)

    Angle, Jesse Isaac

    The XENON Dark Matter Experiment, deployed at the Gran Sasso National Laboratory in Italy on March 2006, is a liquid noble gas detector designed to directly detect dark matter. The detector uses a dual-phase (gas/liquid) Xenon target to search for nuclear recoils associated with nucleus-WIMP interactions. Due to the high sensitivity needed in such an experiment, it is vital to not only reduce the background but to also understand the remaining background so as to aid in the understanding of the data as well as to facilitate upgrades beyond the early Research and Development phases. Many of the components of the XENON10 detector have been screened using a High Purity Germanium Detector known as the GATOR detector. Full analysis of the screening data requires Monte Carlo simulations of the GATOR detector and the sample. Results from this screening will be presented. Using the information obtained from the screening operation, Monte Carlo simulations of the XENON10 electron recoil background will be examined and compared to the actual detector data. The success of this simulation to data comparison indicates that we have a good understanding of the XENON10 gamma background and will be able to make more informed decisions regarding the next stage of detector development. This type of analysis has aided in the selection and design of many of the materials and components being incorporated into the new XENON100 detector, the next generation detector which will be capable of improving the limit set by XENON10 by at least an order of magnitude. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http:/ /www.uflib.ufl.edu/etd.html)

  19. The atmosphere of Mars - Detection of krypton and xenon

    NASA Technical Reports Server (NTRS)

    Owen, T.; Biemann, K.; Biller, J. E.; Lafleur, A. L.; Rushneck, D. R.; Howarth, D. W.

    1976-01-01

    Krypton and xenon have been discovered in the Martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

  20. The atmosphere of Mars: detection of krypton and xenon.

    PubMed

    Owen, T; Biemann, K; Rushneck, D R; Biller, J E; Howarth, D W; Lafleur, A L

    1976-12-11

    Krypton and xenon have been discovered in the martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

  1. Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

    SciTech Connect

    Gulati, P.; Prakash, R.; Pal, U. N.; Kumar, M.; Vyas, V.

    2014-07-07

    A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl{sub 2} deteriorates the performance of the developed source and around 2% Cl{sub 2} in this source produced optimum results. Furthermore, an addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.

  2. Effect of xenon binding to a hydrophobic cavity on the proton pumping cycle in bacteriorhodopsin.

    PubMed

    Hayakawa, Naoki; Kasahara, Takashi; Hasegawa, Daisuke; Yoshimura, Keiko; Murakami, Midori; Kouyama, Tsutomu

    2008-12-26

    To understand the functional role of apolar cavities in bacteriorhodopsin, a light-driven proton pump found in Halobacterium salinarum, we investigated the crystal structure in pressurized xenon or krypton. Diffraction data from the P622 crystal showed that one Xe or Kr atom binds to a preexisting hydrophobic cavity buried between helices C and D, located at the same depth from the membrane surface as Asp96, a key residue in the proton uptake pathway. The occupation fraction of Xe or Kr was calculated as approximately 0.32 at a pressure of 1 MPa. In the unphotolyzed state, the binding of Xe or Kr caused no large deformation of the cavity. However, the proton pumping cycle was greatly perturbed when an aqueous suspension of purple membrane was pressurized with xenon gas; that is, the decay of the M state was accelerated significantly (~5 times at full occupancy), while the decay of an equilibrium state of N and O was slightly decelerated. A similar but much smaller perturbation in the reaction kinetics was observed upon pressurization with krypton gas. In a glycerol/water mixture, xenon-induced acceleration of M decay became less significant in proportion to the water activity. Together with the structure of the xenon-bound protein, these observations suggest that xenon binding helps water molecules permeate into apolar cavities in the proton uptake pathway, thereby accelerating the water-mediated proton transfer from Asp96 to the Schiff base.

  3. Stable Gas Hydrates Beneath a BSR: Implications for Resource Inventories and Shallow Hydrocarbon Fluid Flow

    NASA Astrophysics Data System (ADS)

    Paganoni, M.; Foschi, M.; Cartwright, J. A.; Van Rensbergen, P.; Shipp, R. C.

    2015-12-01

    Bottom simulating reflectors (BSRs) are the primary indicators of the presence of gas hydrate systems and are generally considered to approximate the base of the gas hydrate stability zone. Here we use a combination of well-log, pressure-core, geochemical and high-resolution 3D seismic data, acquired in deepwater NW Borneo, to report the presence of gas hydrates both above and below a BSR at the top of a thrust-related anticline. This complex gas hydrate system overlies a conventional hydrocarbon reservoir. Hydrates beneath the BSR are interpreted to have a thermogenic origin because they contain significant quantities of C2+ hydrocarbons. The base of the hydrate stability coincides at the top of the anticline with a sudden decrease in resistivity in four adjacent wells. Away from the anticline top, in an environment dominated by mass-transport deposits, geochemical data from cores indicate a significant reduction in C2+ hydrocarbons. This change in gas composition is thought to reflect variations in hydrocarbon migration effectiveness and mechanisms. We demonstrate that, where thermogenic gases are efficiently transported to shallow parts of basins, hydrate stability zones could be much thicker than suggested by the depths of BSRs. This means that the carbon stored in thermogenic hydrate systems may be underestimated.

  4. Gas Discharge and Experiments for Plasma Display Panel

    DTIC Science & Technology

    2000-07-01

    margin, luminance, luminous efficiency, Penning effect and Paschen curve with varying gas composition and pressure. For pure helium and neon gas ...The discharge energy of a Xenon atom is easily eliminated by activated gases such as hydrogen. Xenon has been the predominant noble gas dopant that has...mobility of Xe ion in He gas . 9 5. PENNING EFFECT Penning effect does not play a significant role in mixtures of neon with more than a few percent of xenon

  5. Stable boundary approximations for a class of implicit schemes for the one-dimensional inviscid equations of gas dynamics

    NASA Technical Reports Server (NTRS)

    Yee, H. C.; Beam, R. M.; Warming, R. F.

    1981-01-01

    The applicability to practical calculations of recent theoretical developments in the stability analysis of difference approximations for initial-boundary-value problems of the hyperbolic type. For the numerical experiments, select the one-dimensional inviscid gas-dynamic equations in conservation-law form is selected. A class of implicit schemes based on linear multistep methods for ordinary differential equations is chosen and the use of space or space-time extrapolations as implicit or explicit boundary schemes is emphasized. Some numerical examples with various inflow-outflow conditions highlight the commonly discussed issues: explicit versus implicit boundary schemes, unconditionally stable schemes, and underspecification or overspecification of boundary conditions.

  6. Search for double β-decays of 124Xe with XENON100 & XENON1T

    NASA Astrophysics Data System (ADS)

    Fieguth, Alexander; XENON collaboration

    2017-09-01

    The rare nuclear process of two-neutrino double electron capture, where two electrons are simultaneously captured from the atomic shell, has not yet been observed for 124Xe. A detection of this decay would provide a new reference for nuclear matrix element calculations. Moreover, if a neutrinoless mode were discovered, it would prove a Majorana nature of neutrinos and would shed light on the effective neutrino mass. The XENON dark matter project, with its dual-phase xenon time projection chambers XENON100 and XENON1T, is well suited for this rare event searches with signatures in the keV-region. The search with the XENON100 detector, containing 29 g of 124Xe, is explained as well as the outlook of its successor XENON1T, which contains 2 kg of the isotope in its active volume.

  7. Guidelines and recommended terms for expression of stable-isotope-ratio and gas-ratio measurement results

    USGS Publications Warehouse

    Coplen, Tyler B.

    2011-01-01

    To minimize confusion in the expression of measurement results of stable isotope and gas-ratio measurements, recommendations based on publications of the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) are presented. Whenever feasible, entries are consistent with the Système International d'Unités, the SI (known in English as the International System of Units), and the third edition of the International Vocabulary of Basic and General Terms in Metrology (VIM, 3rd edition). The recommendations presented herein are approved by the Commission on Isotopic Abundances and Atomic Weights and are designed to clarify expression of quantities related to measurement of isotope and gas ratios to ensure that quantity equations instead of numerical value equations are used for quantity definitions. Examples of column headings consistent with quantity calculus (also called the algebra of quantities) and examples of various deprecated usages connected with the terms recommended are presented.

  8. Chondritic xenon in the Earth’s mantle

    NASA Astrophysics Data System (ADS)

    Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G.; Füri, Evelyn; Marty, Bernard

    2016-05-01

    Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth’s mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth’s mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth’s accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion.

  9. Stable Isotopic Constraints on Abiogenic Hydrocarbon gas Contributions to Thermogenic Natural gas Resources in the Northern Appalachian Basin, USA

    NASA Astrophysics Data System (ADS)

    Burruss, R. C.; Laughrey, C. D.

    2006-05-01

    The generation of abiogenic methane by serpentinization or by graphite-water reactions in high-grade metamorphic rocks is well documented by isotopic, fluid inclusion, and petrographic studies. However, geochemical evidence is equivocal for abiogenic generation of higher hydrocarbon gases (ethane through pentane) in economic resources. Thermogenic hydrocarbon gases, generated by thermal cracking of sedimentary organic matter of biological origin, are progressively enriched in 13C as a function of increasing number of carbon atoms in the molecule. The isotopic composition is controlled by the kinetic isotope effect (KIE) during carbon-carbon bond breaking with the largest KIE for methane. Published work on gases in Precambrian rocks in Canada and South Africa suggest that some were generated by abiogenic Fischer-Tropsch type reactions that produced gases with carbon isotopic compositions that are reversed from the thermogenic trend. We have documented reversed isotopic compositions in natural gas accumulations in lower Paleozoic reservoirs of the Appalachian basin regionally from West Virginia and eastern Ohio through Pennsylvania to central New York. The regional accumulation in lower Silurian age strata shows progressive enhancement of the isotopic reversal with increasing depth in the basin. Multivariate analysis of the molecular and isotopic data define an end-member in the deep basin with an approximate composition of 98 mol % CH4, 1-2 mol % C2H6, << 1 mol % C3H8, and δ13C (CH4) = -27 ‰, δ13C (C2H6) = -40 ‰, δ13C (C3H8) = - 41‰. The nominal similarity of isotopic reversals in the gases from Precambrian rocks to those in the lower Paleozoic rocks of the Appalachian basin suggests that abiogenic F-T reactions may have generated some fraction of the gases in the deep basin. Comparison of molecular and hydrogen isotopic compositions show that the gases of putative abiogenic F-T origin are significantly different from Appalachian basin gases. All the

  10. Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard.

    PubMed

    Varlet, V; Smith, F; de Froidmont, S; Dominguez, A; Rinaldi, A; Augsburger, M; Mangin, P; Grabherr, S

    2013-06-19

    A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Optical and electron spin resonance studies of xenon-nitrogen-helium condensates containing nitrogen and oxygen atoms.

    PubMed

    Boltnev, Roman E; Bykhalo, Igor B; Krushinskaya, Irina N; Pelmenev, Alexander A; Khmelenko, Vladimir V; Mao, Shun; Meraki, Adil; Wilde, Scott C; McColgan, Patrick T; Lee, David M

    2015-03-19

    We present the first observations of excimer XeO* molecules in molecular nitrogen films surrounding xenon cores of nanoclusters. Multishell nanoclusters form upon the fast cooling of a helium jet containing small admixtures of nitrogen and xenon by cold helium vapor (T = 1.5 K). Such nanoclusters injected into superfluid helium aggregate into porous impurity-helium condensates. Passage of helium gas with admixtures through a radio frequency discharge allows the storage of high densities of radicals stabilized in impurity-helium condensates. Intense recombination of the radicals occurs during destruction of such condensates and generates excited species observable because of optical emission. Rich spectra of xenon-oxygen complexes have been detected upon destruction of xenon-nitrogen-helium condensates. A xenon environment quenches metastable N((2)D) atoms but has a much weaker effect on the luminescence of N((2)P) atoms. Electron spin resonance spectra of N((4)S) atoms trapped in xenon-nitrogen-helium condensates have been studied. High local concentrations of nitrogen atoms (up to 10(21) cm(-3)) stabilized in xenon-nitrogen nanoclusters have been revealed.

  12. Relativistic rise measurement for heavy cosmic rays in xenon

    NASA Technical Reports Server (NTRS)

    Gregory, J. C.; Parnell, T. A.; Watts, J., Jr.

    1982-01-01

    Potential advantages of the use of the relativistic rise of energy loss in gas-filled counters for cosmic ray energy measurement have been noted by Tueller et al. (1979) and Gregory and Parnell (1979). Gregory and Parnell have reported measurements on the relativistic rise for cosmic ray iron nuclei in parallel plate ionization chambers 8.4 cm thick filled with a xenon and methane mixture. The present investigation is concerned with the observed rise and ionization signal fluctuations for a sample of elements from carbon through iron in the cosmic rays. The results are compared with a calculation of the energy deposit within the ion chamber.

  13. Microdischarges of xenon sustained by microwaves: Determination of scaling laws

    SciTech Connect

    Lacoste, A.; Maulat, O.; Latrasse, L.; Arnal, Y.; Pelletier, J.

    2005-04-04

    The threshold conditions to maintain millimeter and submillimeter-size discharges of xenon with microwaves are experimentally determined. The threshold electric field required to sustain the plasma is reported as a function of gas pressure. The influence of the size of the dielectric cell in which the discharge is produced is also shown. The scaling laws are deduced from the threshold electric field measurements, assuming a few additional simplifying assumptions. The results are compared with data obtained with argon discharges sustained by surface waves in capillary tubes and the hypotheses assumed for the calculations are discussed.

  14. Xenon Spectral Gamma Penetrometer Probe Characterization and Calibration

    DTIC Science & Technology

    2004-09-01

    Figure 15. The xenon gas gamma detector demonstrated the capability to fully resolve the two spectral energy lines of actinium -228, a thorium-232 progeny...daughter product), at 911 keV and 969 keV (Figure 15). Since the two actinium -228 spectral energy lines at 911 keV and 969 keV were fully resolved in...demonstrated the capability to detect the two spectral energy lines of actinium -228 but produced a smeared camel-humped peak (i.e., it was unable to

  15. Radiant flash pyrolysis of biomass using a xenon flashtube

    SciTech Connect

    Hopkins, M.W.; Antal, M.J. Jr.

    1984-06-01

    Biomass materials, including lignin, redwood, corn cob, Calotropis Procera, Leucaena wood, Kraft paper, newsprint, cow manure, D-glucose, and D-cellobiose, were pyrolyzed in vacuum by the visible radiant flux emitted from a Xenon flashtube. The flux density exceeded 8 kW/cm/sup 2/ during the 1 ms flash. Sirup yields were low (avg 25%), while the gas yield was high (avg 32%). The gaseous products were composed primarily of CO and CO/sub 2/. The high relative yields of CO establish the existence of a high temperature fragmentation pathway active during the flash pyrolysis of all biomass materials. 39 references, 2 figures, 5 tables.

  16. Development of Liquid Xenon Imaging Gamma-Ray Spectrophotometers

    DTIC Science & Technology

    1990-07-01

    ground potential. The cathode plane is made from 63/rm diameter silver-plated beryllium copper wire set at 0.55mm pitch on a 15cm span. These wires are...100000 ( ! IUD i 10 10000 .. SCUID GAS Pressure Density (torr) 10 ,..........I (gm/cc) 10 1 1 100 120 140 160 180 200 220 240 260 280 300 Temperature (K...The freon is kept in a 30cm diameter by 10cm deep SS cryostat large enough to accomodate a 15cm diameter by 5cm deep liquid xenon cell and copper

  17. Minimum alveolar concentration-awake of Xenon alone and in combination with isoflurane or sevoflurane.

    PubMed

    Goto, T; Nakata, Y; Ishiguro, Y; Niimi, Y; Suwa, K; Morita, S

    2000-11-01

    The minimum alveolar concentration (MAC)-awake is a traditional index of hypnotic potency of an inhalational anesthetic. The MAC-awake of xenon, an inert gas with anesthetic properties (MAC = 71%), has not been determined. It is also unknown how xenon interacts with isoflurane or sevoflurane on the MAC-awake. In the first part of the study, 90 female patients received xenon, nitrous oxide (N2O), isoflurane, or sevoflurane supplemented with epidural anesthesia (n = 36 for xenon and n = 18 per group for other anesthetics). In the second part, 72 additional patients received either xenon or N2O combined with the 0.5 times MAC-awake concentration of isoflurane or sevoflurane (0.2% and 0.3%, respectively, based on the results of the first part; n = 18 per group). During emergence, the concentration of an assigned anesthetic (xenon or N2O only in the second part) was decreased in 0. 1 MAC decrements every 15 min from 0.8 MAC or from 70% in the case of N2O until the patient followed the command to either open her eyes or to squeeze and release the investigator's hand. The concentration midway between the value permitting the first response to command and that just preventing it was defined as the MAC-awake. The MAC-awake were as follows: xenon, 32.6 +/- 6.1% (mean +/- SD) or 0.46 +/- 0.09 MAC; N2O, 63.3 +/- 7.1% (0.61 +/- 0.07 MAC); isoflurane, 0.40 +/- 0.07% (0.35 +/- 0.06 MAC); and sevoflurane, 0.59 +/- 0.10% (0.35 +/- 0.06 MAC). Addition of the 0.5 MAC-awake concentrations of isoflurane and sevoflurane reduced the MAC-awake of xenon to 0.50 +/- 0.15 and 0.51 +/- 0.16 times its MAC-awake as a sole agent, but that of N2O to the values significantly greater than 0.5 times its MAC-awake as a sole agent (0.68 +/- 0.12 and 0.66 +/- 0.14 times MAC-awake; P < 0.01, analysis of variance and Dunnett's test). The MAC-awake of xenon is 33% or 0.46 times its MAC. In terms of the MAC-fraction, this is smaller than that for N2O but greater than those for isoflurane and sevoflurane

  18. Electron attachment of oxygen in a drift chamber filled with xenon + 10% methane

    NASA Astrophysics Data System (ADS)

    Chiba, Y.; Hayashibara, I.; Ohsugi, T.; Sakanoue, T.; Taketani, A.; Terunuma, N.; Suzuki, Y.; Tsukamoto, A.; Yamamoto, H.; Fukushima, Y.; Kohriki, T.; Nakamura, S.; Sakuda, M.; Watase, Y.

    1988-06-01

    The existence of O 2 contamination attenuates the pulse height and degrades its resolution in a drift chamber filled with xenon-methane (90/10) gas. The first measurement of the electron attachment coefficient due to oxygen in such a mixture is reported.

  19. Rn-222 tracing and stable isotope measurements of biogenic gas fluxes from methane saturated sediments

    NASA Technical Reports Server (NTRS)

    Martens, Christopher S.; Green, C. D.; Blair, Neal; Chanton, J. P.

    1985-01-01

    Transport of reduced biogenic gases from anoxic sediments and soils to the atmosphere can be quantitatively studied through measurement of radon-222/radium-226 disequilibrium. In previous work, seasonal variations in biogenic gas transport mechanisms, net fluxes and overall composition were documented. Now presented are direct field measurements of radon-222 activity in gases exiting organic rich sediments which show their usefulness for tracing of the stripping of dissolved biogenic gases from within the sediment column and transport via bubble ebullition. Methane is depleted in deuterium during the summer as compared with winter months and is in general lighter than in most marine sediments signaling the probable importance of acetate as an important precursor molecule. The significant seasonal isotopic variations observed illustrate the importance of understanding mechanisms and rates of biogenic gas production in order to interpret observed tropospheric isotopic data.

  20. Rn-222 tracing and stable isotope measurements of biogenic gas fluxes from methane saturated sediments

    NASA Technical Reports Server (NTRS)

    Martens, Christopher S.; Green, C. D.; Blair, Neal; Chanton, J. P.

    1985-01-01

    Transport of reduced biogenic gases from anoxic sediments and soils to the atmosphere can be quantitatively studied through measurement of radon-222/radium-226 disequilibrium. In previous work, seasonal variations in biogenic gas transport mechanisms, net fluxes and overall composition were documented. Now presented are direct field measurements of radon-222 activity in gases exiting organic rich sediments which show their usefulness for tracing of the stripping of dissolved biogenic gases from within the sediment column and transport via bubble ebullition. Methane is depleted in deuterium during the summer as compared with winter months and is in general lighter than in most marine sediments signaling the probable importance of acetate as an important precursor molecule. The significant seasonal isotopic variations observed illustrate the importance of understanding mechanisms and rates of biogenic gas production in order to interpret observed tropospheric isotopic data.

  1. Stable Laser-Driven Electron Beams from a Steady-State-Flow Gas Cell

    SciTech Connect

    Osterhoff, J.; Popp, A.; Karsch, S.; Major, Zs.; Marx, B.; Fuchs, M.; Hoerlein, R.; Gruener, F.; Habs, D.; Krausz, F.; Rowlands-Rees, T. P.; Hooker, S. M.

    2009-01-22

    Quasi-monoenergetic, laser-driven electron beams of up to {approx}200 MeV in energy have been generated from steady-state-flow gas cells [1]. These beams are emitted within a low-divergence cone of 2.1{+-}0.5 mrad FWHM and feature unparalleled shot-to-shot stability in energy (2.5% rms), pointing direction (1.4 mrad rms) and charge (16% rms) owing to a highly reproducible plasma-density profile within the laser-plasma-interaction volume. Laser-wakefield acceleration (LWFA) in gas cells of this type constitutes a simple and reliable source of relativistic electrons with well defined properties, which should allow for applications such as the production of extreme-ultraviolet undulator radiation in the near future.

  2. Genetically encoded reporters for hyperpolarized xenon magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Shapiro, Mikhail G.; Ramirez, R. Matthew; Sperling, Lindsay J.; Sun, George; Sun, Jinny; Pines, Alexander; Schaffer, David V.; Bajaj, Vikram S.

    2014-07-01

    Magnetic resonance imaging (MRI) enables high-resolution non-invasive observation of the anatomy and function of intact organisms. However, previous MRI reporters of key biological processes tied to gene expression have been limited by the inherently low molecular sensitivity of conventional 1H MRI. This limitation could be overcome through the use of hyperpolarized nuclei, such as in the noble gas xenon, but previous reporters acting on such nuclei have been synthetic. Here, we introduce the first genetically encoded reporters for hyperpolarized 129Xe MRI. These expressible reporters are based on gas vesicles (GVs), gas-binding protein nanostructures expressed by certain buoyant microorganisms. We show that GVs are capable of chemical exchange saturation transfer interactions with xenon, which enables chemically amplified GV detection at picomolar concentrations (a 100- to 10,000-fold improvement over comparable constructs for 1H MRI). We demonstrate the use of GVs as heterologously expressed indicators of gene expression and chemically targeted exogenous labels in MRI experiments performed on living cells.

  3. Metabolism of Inhaled Brominated Hydrocarbons: Validation of Gas Uptake Results by Determination of a Stable Metabolite

    DTIC Science & Technology

    1982-02-10

    Chemical Co., Midla 1, Mich . chloromethane, and methyl bromide. These ’ Analabs "Hi Plates." high-efficiency packed column, chemicals had been...semilogarithmic. system. For this paper we have fitted both gas uptake ventilation and cardiac output, respectively, and Eis and bromide production data...regarded as a convenience to allow comparison of the blood flow is 25% of cardiac output. This limiting be- I curves obtained by the two, independent

  4. Stable isotope profiles of nitrogen gas indicate denitrification in oxygen-stratified humic lakes.

    PubMed

    Tiirola, Marja A; Rissanen, Antti J; Sarpakunnas, Miika; Arvola, Lauri; Nykänen, Hannu

    2011-06-15

    Mid-summer N(2) profiles were analyzed from nine oxygen-stratified, humic-acid-rich lakes using a continuous flow isotope ratio mass spectrometer and a Gasbench II device. Sample preparation steps were performed under water to avoid air contamination. The instrument precision for the δ(15)N measurement was high (0.03‰), but for the whole sampling and analysis procedure the mean deviation between replicate samples was 0.13‰ for the δ(15)N measurements and 5.5% for the N(2) gas concentration analysis. The results show that the Gasbench peripheral was suitable for measurement of the (15)N natural abundance of dissolved nitrogen gas, with denitrification indicated by the oversaturation and slightly (<1‰) depleted δ(15)N values of the dissolved N(2) gas in the suboxic zones of some of the study lakes. Calculated values for the denitrified (excess) N(2) varied between -5.3 and 0.7‰. The denitrification potential was determined using the (15)N tracer method, with results showing nitrate-inducible denitrification and no signs of anaerobic ammonium oxidation (anammox). Copyright © 2011 John Wiley & Sons, Ltd.

  5. Irreversible xenon insertion into a small-pore zeolite at moderate pressures and temperatures

    DOE PAGES

    Seoung, Donghoon; Cynn, Hyunchae; Park, Changyong; ...

    2014-09-01

    Pressure drastically alters the chemical and physical properties of materials and allows structural phase transitions and chemical reactions to occur that defy much of our understanding gained under ambient conditions. Particularly exciting is the high-pressure chemistry of xenon, which is known to react with hydrogen and ice at high pressures and form stable compounds. Here, we show that Ag16Al16Si24O8·16H2O (Ag-natrolite) irreversibly inserts xenon into its micropores at 1.7 GPa and 250 °C, while Ag+ is reduced to metallic Ag and possibly oxidized to Ag2+. In contrast to krypton, xenon is retained within the pores of this zeolite after pressure releasemore » and requires heat to desorb. This irreversible insertion and trapping of xenon in Ag-natrolite under moderate conditions sheds new light on chemical reactions that could account for the xenon deficiency relative to argon observed in terrestrial and Martian atmospheres.« less

  6. Irreversible xenon insertion into a small-pore zeolite at moderate pressures and temperatures

    SciTech Connect

    Seoung, Donghoon; Cynn, Hyunchae; Park, Changyong; Choi, Kwang -Yong; Blom, Douglas A.; Evans, William J.; Kao, Chi -Chang; Vogt, Thomas; Lee, Yongjae

    2014-09-01

    Pressure drastically alters the chemical and physical properties of materials and allows structural phase transitions and chemical reactions to occur that defy much of our understanding gained under ambient conditions. Particularly exciting is the high-pressure chemistry of xenon, which is known to react with hydrogen and ice at high pressures and form stable compounds. Here, we show that Ag16Al16Si24O8·16H2O (Ag-natrolite) irreversibly inserts xenon into its micropores at 1.7 GPa and 250 °C, while Ag+ is reduced to metallic Ag and possibly oxidized to Ag2+. In contrast to krypton, xenon is retained within the pores of this zeolite after pressure release and requires heat to desorb. This irreversible insertion and trapping of xenon in Ag-natrolite under moderate conditions sheds new light on chemical reactions that could account for the xenon deficiency relative to argon observed in terrestrial and Martian atmospheres.

  7. Surface diffusion of xenon on Pt(111)

    NASA Astrophysics Data System (ADS)

    Meixner, D. Laurence; George, Steven M.

    1993-06-01

    The surface diffusion of xenon on the Pt(111) surface was investigated using laser induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. The surface diffusion coefficient at 80 K decreased dramatically from D=8×10-7 cm2/s at θ=0.05θs to approximately D=2×10-8 cm2/s at θ=θs, where θs denotes the saturation coverage at 85 K, corresponding to a commensurate monolayer coverage of 5.0×1014 xenon atoms/cm2. This coverage dependence was consistent with attractive interactions between the adsorbed xenon atoms and the existence of two-dimensional condensed phases of xenon on Pt(111). The kinetic parameters for surface diffusion at θ=θs were Edif=1.3±0.1 kcal/mol and D0=1.1×10-4±0.2 cm2/s. The magnitude of Edif at θ=θs represented the combined effect of the intrinsic corrugation of the adsorbate-surface potential and attractive interactions between the adsorbed xenon atoms. LITD experiments at θ=0.25 θs revealed diffusion kinetic parameters of Edif=1.2±0.2 kcal/mol and D0=3.4×10-4±0.5 cm2/s. The constant Edif at low and high coverage was attributed to the ``breakaway'' of xenon atoms from the edges of condensed phase xenon islands. The coverage dependence of the surface diffusion coefficient for Xe/Pt(111) was explained by a multiple site diffusion mechanism, where collisions with xenon islands limit diffusional motion. Thermal desorption kinetics for xenon on Pt(111) were determined using TPD experiments. Using the variation of heating rates method, the desorption parameters were Edes=6.6±0.2 kcal/mol and νdes=1.3×1013±0.4 s-1, in good agreement with previous studies. The xenon TPD peak shifted to higher temperature versus initial coverage at a fixed heating rate, providing further evidence for attractive interactions between the adsorbed xenon atoms.

  8. Pressurized laboratory experiments show no stable carbon isotope fractionation of methane during gas hydrate dissolution and dissociation.

    PubMed

    Lapham, Laura L; Wilson, Rachel M; Chanton, Jeffrey P

    2012-01-15

    The stable carbon isotopic ratio of methane (δ(13)C-CH(4)) recovered from marine sediments containing gas hydrate is often used to infer the gas source and associated microbial processes. This is a powerful approach because of distinct isotopic fractionation patterns associated with methane production by biogenic and thermogenic pathways and microbial oxidation. However, isotope fractionations due to physical processes, such as hydrate dissolution, have not been fully evaluated. We have conducted experiments to determine if hydrate dissolution or dissociation (two distinct physical processes) results in isotopic fractionation. In a pressure chamber, hydrate was formed from a methane gas source at 2.5 MPa and 4 °C, well within the hydrate stability field. Following formation, the methane source was removed while maintaining the hydrate at the same pressure and temperature which stimulated hydrate dissolution. Over the duration of two dissolution experiments (each ~20-30 days), water and headspace samples were periodically collected and measured for methane concentrations and δ(13)C-CH(4) while the hydrate dissolved. For both experiments, the methane concentrations in the pressure chamber water and headspace increased over time, indicating that the hydrate was dissolving, but the δ(13)C-CH(4) values showed no significant trend and remained constant, within 0.5‰. This lack of isotope change over time indicates that there is no fractionation during hydrate dissolution. We also investigated previous findings that little isotopic fractionation occurs when the gas hydrate dissociates into gas bubbles and water due to the release of pressure. Over a 2.5 MPa pressure drop, the difference in the δ(13)C-CH(4) was <0.3‰. We have therefore confirmed that there is no isotope fractionation when the gas hydrate dissociates and demonstrated that there is no fractionation when the hydrate dissolves. Therefore, measured δ(13)C-CH(4) values near gas hydrates are not affected

  9. Transportable Xenon Laboratory (TXL-1) Operations Manual

    SciTech Connect

    Thompson, Robert C.; Stewart, Timothy L.; Willett, Jesse A.; Woods, Vincent T.

    2011-03-07

    The Transportable Xenon Laboratory Operations Manual is a guide to set up and shut down TXL, a fully contained laboratory made up of instruments to identify and measure concentrations of the radioactive isotopes of xenon by taking air samples and analyzing them. The TXL is housed in a standard-sized shipping container. TXL can be shipped to and function in any country in the world.

  10. Measurement of Xenon Viscosity as a Function of Low Temperature and Pressure

    NASA Technical Reports Server (NTRS)

    Grisnik, Stanley P.

    1998-01-01

    The measurement of xenon gas viscosity at low temperatures (175-298 K) and low pressures (350 torr-760 torr) has been performed in support of Hall Thruster testing at NASA Lewis Research Center. The measurements were taken using the capillary flow technique. Viscosity measurements were repeatable to within 3%. The results in this paper are in agreement with data from Hanley and Childs and suggest that the data from Clarke and Smith is approximately 2% low. There are no noticeable pressure effects on xenon absolute viscosity for the pressure range from 350 torr to 760 torr.

  11. The use of stable isotopes and gas chromatography/mass spectrometry in the identification of steroid metabolites in the equine

    SciTech Connect

    Houghton, E.; Dumasia, M.C.; Teale, P.; Smith, S.J.; Cox, J.; Marshall, D.; Gower, D.B. )

    1990-10-01

    Stable isotope gas chromatography/mass spectrometry has been used successfully in the elucidation of structures of urinary steroid metabolites in the horse and in the identification of metabolites isolated from in vivo perfusion and in vitro incubation studies using equine tissue preparations. Deuterium-labeled steroids, testosterone, dehydroepiandrosterone, and 5-androstene-3 beta,17 beta-diol have been synthesized by base-catalyzed isotope exchange methods and the products characterized by gas chromatography/mass spectrometry. (16,16(-2)H2)Dehydroepiandrosterone (plus radiolabeled dehydroepiandrosterone) was perfused into a testicular artery of a pony stallion and was shown to be metabolized into 2H2-labeled testosterone, 4-androstenedione, isomers of 5-androstene-3,17-diol, 19-hydroxytestosterone, and 19-hydroxy-4-androstenedione. In further studies, equine testicular minces have been incubated with 2H2-labeled and radiolabeled dehydroepiandrosterone and 5-androstene-3 beta, 17 beta-diol. The metabolites, whose identity was confirmed by stable isotope gas chromatography/mass spectrometry, proved the interconversion of the two substrates, as well as formation of testosterone and 4-androstenedione. The aromatization of dehydroepiandrosterone was also confirmed, together with the formation of an isomer of 5(10)-estrene-3,17-diol from both substrates showing 19-demethylation without concomitant aromatization. In studies of the feto-placental unit, the allantochorion was shown to aromatize (2H5)testosterone to (2H4)estradiol, the loss of one 2H from the substrate being consistent with aromatization of the A ring. The formation of 6-hydroxyestradiol was also confirmed in this study. The same technique has been valuable in determining the structure of two metabolites of nandrolone isolated from horse urine.

  12. [Xenon CT CBF mapping derived from two minutes inhalation].

    PubMed

    Toshima, R; Toyohara, K; Ebisawa, T; Ishikawa, K; Karashima, H; Shimojo, S; Miyahara, T

    1988-04-01

    Although xenon enhanced CT method for local cerebral blood flow measurement has been brought into a clinical practice, the technique has inherent limitations including anesthetic effects and expensive cost of xenon by a large consumption. To overcome these problems a modified method with a short-duration inhalation was developed and its validity was attested. Siemens Somatom SF with a resolution of 256 X 256 pixels and a scan time of 10 seconds was used. The subjects inhaled 50% Xe/O2 gas mixture from an apparatus consisted of Douglas bag and an open circuit. Xenon concentration in the expired gas was continuously monitored and estimated for arterial blood concentration by using a hematocrit correction. PaCO2 was monitored throughout the study. At the starting point and the endpoint of the inhalation two scans were performed respectively. Thus obtained four images were processed for CT noise cancellation, summation and subtraction to produce an in vivo autoradiography image. Local CBF was calculated from equations derived from the autoradiographic technique with a fixed partition coefficient of lambda = 1. Computer simulation studies were performed to find the optimal scan point to obtain an autoradiographic image and to estimate the calculation errors of this method. One minute and forty-five seconds was found to be the optimal scan point to gain an autoradiographic image in view of a balance between linearity of CBF/enhancement curve and total amount of tissue enhancement. The theoretical errors due to the assumption for a fixed partition coefficient were calculated to be 8% underestimation for gray matter and 5% overestimation for white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Design and First Results of the CoDeX Liquid-Xenon Compton-Imaging Detector

    NASA Astrophysics Data System (ADS)

    Tennyson, Brian; Cahn, Sidney; Bernard, Ethan; Boulton, Elizabeth; Destefano, Nicholas; Edwards, Blair; Hackenburg, Ariana; Horn, Markus; Larsen, Nicole; Nikkel, James; Wahl, Christopher; Gai, Moshe; McKinsey, Daniel

    2016-03-01

    CoDeX (Compton-imaging Detector in Xenon) is an R&D Compton gamma-ray imaging detector that uses 30 kg of xenon in a two-phase time projection chamber. Time projection relative to the initial scintillation signal provides the vertical interaction positions, and either PMT-sensed gas electroluminescence or a charge-sensitive amplifier quantifies the drifted ionization signal. Detector features to enable Compton imaging are a pair of instrumented wire grids added to sense the horizontal position of clouds of drifted electrons that traverse the detector. Each wire is individually amplified in the cold xenon environment. Design choices addressing the thermodynamic and xenon purity constraints of this system will be discussed. We will also discuss the mechanical designs, engineering challenges, and performance of this Compton-imaging detector.

  14. Dynamics of the sputtering of water from ice films by collisions with energetic xenon atoms.

    PubMed

    Killelea, Daniel R; Gibson, K D; Yuan, Hanqiu; Becker, James S; Sibener, S J

    2012-04-14

    The flow of energy from the impact site of a heavy, translationally energetic xenon atom on an ice surface leads to several non-equilibrium events. The central focus of this paper is on the collision-induced desorption (sputtering) of water molecules into the gas-phase from the ice surface. Sputtering is strongly activated with respect to xenon translational energy, and a threshold for desorption was observed. To best understand these results, we discuss our findings in the context of other sputtering studies of molecular solids. The sputtering yield is quite small; differential measurements of the energy of xenon scattered from ice surfaces show that the ice efficiently accommodates the collisional energy. These results are important as they quantitatively elucidate the dynamics of such sputtering events, with implications for energetic non-equilibrium processes at interfaces.

  15. Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

    SciTech Connect

    Vernieres, Jerome Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E.; Bobo, Jean-François; Sowwan, Mukhles

    2014-11-01

    Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

  16. Stable detonation characteristics of premixed C2H4/O2 gas in narrow gaps

    NASA Astrophysics Data System (ADS)

    Zhu, Yuejin; Pan, Zhenhua; Zhang, Penggang; Pan, Jianfeng

    2017-09-01

    The detonation initiation and propagation characteristics of premixed gas in a confined channel are greatly influenced by some external factors, such as the channel size and the initial pressure. The influences of different gap height and initial pressure of stoichiometric C2H4/O2 combustible premixed gas on the detonation characteristics were investigated using the self-made narrow gaps. The flame propagation processes were captured by the high-speed photography and the detonation trajectories were recorded by the soot-foil technology. The results show that the gap height is found to be proportional to P0^{ - 1.493} of the dividing lines, which are used to distinguish the three different detonation states. The detonation initiation process can be accelerated by either decreasing the gap height or increasing the initial pressure. Furthermore, the detonation velocity deficit is closely related to the gap height and the initial pressure, and the relation can be expressed as dV ∝ H^{ - 0.8} P0^{ - 0.5}.

  17. Highly stable and regenerable Mn-based/SBA-15 sorbents for desulfurization of hot coal gas.

    PubMed

    Zhang, F M; Liu, B S; Zhang, Y; Guo, Y H; Wan, Z Y; Subhan, Fazle

    2012-09-30

    A series of mesoporous xCuyMn/SBA-15 sorbents with different Cu/Mn atomic ratios were prepared by wet impregnation method and their desulfurization performance in hot coal gas was investigated in a fixed-bed quartz reactor in the range of 700-850°C. The successive nine desulfurization-regeneration cycles at 800°C revealed that 1Cu9Mn/SBA-15 presented high performance with durable regeneration ability due to the high dispersion of Mn(2)O(3) particles incorporated with a certain amount of copper oxides. The breakthrough sulfur capacity of 1Cu9Mn/SBA-15 observed 800°C is 13.8 g S/100g sorbents, which is remarkably higher than these of 40 wt%LaFeO(3)/SBA-15 (4.8 g S/100g sorbents) and 50 wt%LaFe(2)O(x)/MCM-41 (5.58 g S/100g sorbents) used only at 500-550°C. This suggested that the loading of Mn(2)O(3) active species with high thermal stability to SBA-15 support significantly increased sulfur capacity at relatively higher sulfidation temperature. The fresh and used xCuyMn/SBA-15 sorbents were characterized by means of BET, XRD, XPS, XAES, TG/DSC and HRTEM techniques, confirmed that the structure of the sorbents remained intact before and after hot coal gas desulfurization.

  18. Highly active and stable iron Fischer-Tropsch catalyst for synthesis gas conversion to liquid fuels

    SciTech Connect

    Bukur, D.B.; Lang, X.

    1999-09-01

    A precipitated iron Fischer-Tropsch (F-T) catalyst (100 Fe/3 Cu/4 K/16 SiO{sub 2} on mass basis) was tested in a stirred tank slurry reactor under reaction conditions representative of industrial practice using CO-rich synthesis gas (260 C, 1.5--2.2 MPa, H{sub 2}/CO = 2/3). Repeatability of performance and reproducibility of catalyst preparation procedure were successfully demonstrated on a laboratory scale. Catalyst productivity was increased by operating at higher synthesis pressure while maintaining a constant contact time in the reactor and through the use of different catalyst pretreatment procedures. In one of the tests (run SA-2186), the catalyst productivity was 0.86 (g hydrocarbons/g Fe/h) at syngas conversion of 79%, methane selectivity of 3% (weight percent of total hydrocarbons produced), and C{sub 5}+ hydrocarbon selectivity of 83 wt %. This represents a substantial improvement in productivity in comparison to state-of-the-art iron F-T catalysts. This catalyst is ideally suited for production of high-quality diesel fuels and C{sub 2}-c{sub 4} olefins from a coal-derived synthesis gas.

  19. Design of Solid Form Xenon-124 Target for Producing I-123 Radioisotope Using Computer Simulation Techniques

    SciTech Connect

    Kamali Moghaddam, K.; Sadeghi, M.; Kakavand, T.; Shokri Bonab, S.

    2006-07-01

    Recently in Cyclotron and Nuclear Medicine Department of NRCAM, at Atomic Energy organization of Iran (AEOI), a system for producing 1-123 via Xe-124 gas target technology, has been constructed and installed. One of the major problems in this system is the highly expensive cost of the enriched Xenon-124 gas. Therefore, saving this gas inside the system is very important. Unfortunately, by accidental rupture of the window foil or bad function of O-rings, the whole Xenon gas will escape from the system immediately. In this paper, by using computer codes; ALICE91, SRIM and doing some calculations we are going to demonstrate our latest effort for feasibility study of producing I-123 with the above mentioned reactions, but using Xe-124 solid target instead. According to our suggested design, a conical shaped irradiation vessel made of copper with 1 mm thickness, 1 cm outlet diameter, 5 cm length and 12 deg. angle at summit can be fixed inside a liquid nitrogen housing chamber. The Xenon-124 gas will be sent to the inside of this very cold conical trap and eventually deposited on its surface in solid form. Our calculation shows that during bombardment with 17-28 MeV proton energy, the thickness of solidified Xenon layer will remain around .28 mm. Likewise; thermo-dynamical calculation shows that in order to prevent the evaporation of solidified Xenon, the maximum permissible proton beam current for this system should be less than 1.4 {mu}A. According to these working conditions, the production yield of I-123 can be predicted to be around 150 mCi/{mu}Ah. (authors)

  20. Simple, stable and reliable modeling of gas properties of organic working fluids in aerodynamic designs of turbomachinery for ORC and VCC

    NASA Astrophysics Data System (ADS)

    Kawakubo, T.

    2016-05-01

    A simple, stable and reliable modeling of the real gas nature of the working fluid is required for the aerodesigns of the turbine in the Organic Rankine Cycle and of the compressor in the Vapor Compression Cycle. Although many modern Computational Fluid Dynamics tools are capable of incorporating real gas models, simulations with such a gas model tend to be more time-consuming than those with a perfect gas model and even can be unstable due to the simulation near the saturation boundary. Thus a perfect gas approximation is still an attractive option to stably and swiftly conduct a design simulation. In this paper, an effective method of the CFD simulation with a perfect gas approximation is discussed. A method of representing the performance of the centrifugal compressor or the radial-inflow turbine by means of each set of non-dimensional performance parameters and translating the fictitious perfect gas result to the actual real gas performance is presented.

  1. Stirring Up an Elastic Fluid: Critical Viscosity of Xenon-2 (CVX-2)

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.; Motil, Susan M. (Technical Monitor)

    2002-01-01

    Whipped cream stays in place even when turned upside down. Yet it readily flows through the nozzle of a spray can to reach the dessert plate. This demonstrates the phenomenon of shear thinning that is important to many industrial and physical processes. Paints, film emulsions, and other complex solutions that are highly viscous under normal conditions but become thin and flow easily under shear forces. A simple fluid, such as water, does not exhibit shear thinning under normal conditions. Very close to the liquid-vapor critical point, where the distinction between liquid and vapor disappears, the fluid becomes more complex and is predicted to display shear thinning. At the critical point, xenon atoms interact over long distances in a classical model of cooperative phenomena. Physicists rely on this system to learn how long-range order arises. The Critical Viscosity of Xenon Experiment (CVX-2) will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of fluids. Viscosity originates from the interactions of individual molecules. It is so complicated that, except for the simplest gas, it cannot be calculated accurately from theory. Tests with critical fluids can provide key data, but are limited on Earth because critical fluids are highly compressed by gravity. CVX-2 employs a tiny metal screen vibrating between two electrodes in a bath of critical xenon. The vibrations and how they dampen are used to measure viscosity. CVX flew on STS-85 (1997), where it revealed that, close to the critical point, the xenon is partly elastic: it can 'stretch' as well as flow. For STS-107, the hardware has been enhanced to determine if critical xenon is a shear-thinning fluid.

  2. Stirring Up an Elastic Fluid: Critical Viscosity of Xenon-2 (CVX-2)

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.; Motil, Susan M. (Technical Monitor)

    2002-01-01

    Whipped cream stays in place even when turned upside down. Yet it readily flows through the nozzle of a spray can to reach the dessert plate. This demonstrates the phenomenon of shear thinning that is important to many industrial and physical processes. Paints, film emulsions, and other complex solutions that are highly viscous under normal conditions but become thin and flow easily under shear forces. A simple fluid, such as water, does not exhibit shear thinning under normal conditions. Very close to the liquid-vapor critical point, where the distinction between liquid and vapor disappears, the fluid becomes more complex and is predicted to display shear thinning. At the critical point, xenon atoms interact over long distances in a classical model of cooperative phenomena. Physicists rely on this system to learn how long-range order arises. The Critical Viscosity of Xenon Experiment (CVX-2) will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of fluids. Viscosity originates from the interactions of individual molecules. It is so complicated that, except for the simplest gas, it cannot be calculated accurately from theory. Tests with critical fluids can provide key data, but are limited on Earth because critical fluids are highly compressed by gravity. CVX-2 employs a tiny metal screen vibrating between two electrodes in a bath of critical xenon. The vibrations and how they dampen are used to measure viscosity. CVX flew on STS-85 (1997), where it revealed that, close to the critical point, the xenon is partly elastic: it can 'stretch' as well as flow. For STS-107, the hardware has been enhanced to determine if critical xenon is a shear-thinning fluid.

  3. XENON dark matter searches: Results and the future

    SciTech Connect

    Brown, Andrew; Collaboration: XENON Collaboration

    2014-06-24

    XENON100 is a dark matter search experiment looking for elastic WIMP scattering using a 62 kg liquid target. WIMP search data from XENON100 published in 2012 has set the world's strongest limits on WIMP-nucleus spinindependent, elastic scattering. It has also set the strongest limits on WIMP-nucleus spin-dependent scattering considering neutron scattering only, and competitive limits considering proton scattering only. The successor experiment to XENON100, XENON1T, is currently under construction, with commissioning scheduled to begin in 2014. XENON1T's design goal is a 100 fold increase in sensitivity for elastic WIMP searches over XENON100.

  4. Xenon-Enhanced Dual-Energy CT Imaging in Combined Pulmonary Fibrosis and Emphysema

    PubMed Central

    Kobayashi, Masahiro; Nakamura, Yasuhiko; Gocho, Kyoko; Ishida, Fumiaki; Isobe, Kazutoshi; Shiraga, Nobuyuki; Homma, Sakae

    2017-01-01

    Background Little has been reported on the feasibility of xenon-enhanced dual-energy computed tomography (Xe-DECT) in the visual and quantitative analysis of combined pulmonary fibrosis and emphysema (CPFE). Objectives We compared CPFE with idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), as well as correlation with parameters of pulmonary function tests (PFTs). Methods Studied in 3 groups were 25 patients with CPFE, 25 with IPF without emphysema (IPF alone), 30 with COPD. Xe-DECT of the patients’ entire thorax was taken from apex to base after a patient’s single deep inspiration of 35% stable nonradioactive xenon. The differences in several parameters of PFTs and percentage of areas enhanced by xenon between 3 groups were compared and analyzed retrospectively. Results The percentage of areas enhanced by xenon in both lungs were calculated as CPFE/IPF alone/COPD = 72.2 ± 15.1% / 82.2 ± 14.7% /45.2 ± 23.2%, respectively. In the entire patients, the percentage of areas enhanced by xenon showed significantly a positive correlation with FEV1/FVC (R = 0.558, P < 0.0001) and %FEV1, (R = 0.528, P < 0.0001) and a negative correlation with %RV (R = -0.594, P < 0.0001) and RV/TLC (R = -0.579, P < 0.0001). The percentage of areas enhanced by xenon in patients with CPFE showed significantly a negative correlation with RV/TLC (R = -0.529, P = 0.007). Xenon enhancement of CPFE indicated 3 different patterns such as upper predominant, diffuse, and multifocal defect. The percentage of areas enhanced by xenon in upper predominant defect pattern was significantly higher than that in diffuse defect and multifocal defect pattern among these 3 different patterns in CPFE. Conclusion The percentage of areas enhanced by xenon demonstrated strong correlations with obstructive ventilation impairment. Therefore, we conclude that Xe-DECT may be useful for distinguishing emphysema lesion from fibrotic lesion in CPFE. PMID:28107411

  5. Magnetization transfer from laser-polarized xenon to protons located in the hydrophobic cavity of the wheat nonspecific lipid transfer protein

    PubMed Central

    Landon, Céline; Berthault, Patrick; Vovelle, Françoise; Desvaux, Hervé

    2001-01-01

    Nonspecific lipid transfer protein from wheat is studied by liquid-state NMR in the presence of xenon. The gas–protein interaction is indicated by the dependence of the protein proton chemical shifts on the xenon pressure and formally confirmed by the first observation of magnetization transfer from laser-polarized xenon to the protein protons. Twenty-six heteronuclear nOes have allowed the characterization of four interaction sites inside the wheat ns-LTP cavity. Their locations are in agreement with the variations of the chemical shifts under xenon pressure and with solvation simulations. The richness of the information obtained by the noble gas with a nuclear polarization multiplied by ∼12,000 makes this approach based on dipolar cross-relaxation with laser-polarized xenon promising for probing protein hydrophobic pockets at ambient pressure. PMID:11274467

  6. Compound-Specific Stable Carbon Isotope Analysis of Low-Concentration Complex Hydrocarbon Mixtures from Natural Gas Hydrate Systems

    NASA Astrophysics Data System (ADS)

    Plummer, R. E.; Pohlman, J. W.; Coffin, R. B.

    2005-12-01

    A system has been developed to measure the stable carbon isotope (δ13C) composition of dissolved methane, ethane, and propane from natural sediment samples with headspace concentrations as low as 1 ppm using a modified Thermo Electron Trace gas chromatograph (GC) connected to a Finnigan Delta Plus XP isotope ratio mass spectrometer (IRMS). A cryofocusing inlet was connected to the GC which allows 0.02- to 15.0-ml injections into a 10-ml min-1 He carrier stream. Analytes from the variable-volume injection are focused into a small section of fused silica capillary, which is either empty or packed with Poraplot-Q, depending on the analyte(s) of interest. The analytes are then rapidly desorbed (100°C) onto the GC column (1.8 ml min-1), where they undergo separation, combustion and IRMS detection. The sensitivity of the IRMS was improved by the addition of high resistivity amplifiers so that measurements can be obtained with as little as 7-ng of carbon. The analytical precision (2σ) is less than 0.5‰ for methane analysis and less than 1‰ for ethane and propane analyses. The gases are standardized by tank CO2 which has been referenced to the NIST RM 8560 natural gas standard. The samples require no pretreatment, and can be analyzed rapidly (20 samples/day) and with minimal instrument training. Using this system, we have obtained complete stable carbon isotope ethane profiles from sediment cores from microbial and thermogenic gas hydrate regions on the Northern Cascadia Margin. We were able to differentiate the relative thermal and microbial contributions of the gases; and furthermore, we obtained clear evidence for ethanogenesis and ethane oxidation at depths similar to those where methanogenesis and anaerobic methane oxidation (AOM), respectively, occurred. This system will be utilized to analyze headspace and hydrate gas samples from IODP Leg 311. These data will allow us to fully characterize the thermogenic contributions and trace hydrocarbon biogeochemical

  7. Xenon lighting adjusted to plant requirements

    NASA Technical Reports Server (NTRS)

    Koefferlein, M.; Doehring, T.; Payer, Hans D.; Seidlitz, H. K.

    1994-01-01

    Xenon lamps are available as low and high power lamps with relatively high efficiency and a relatively long lifetime up to several thousand hours. Different construction types of short-arc and long-arc lamps permit a good adaptation to various applications in projection and illumination techniques without substantial changes of the spectral quality. Hence, the xenon lamp was the best choice for professional technical purposes where high power at simultaneously good spectral quality of the light was required. However, technical development does not stand still. Between the luminous efficacy of xenon lamps of 25-50 lm/W and the theoretical limit for 'white light' of 250 lm/W is still much room for improvement. The present development mainly favors other lamp types, like metal halide lamps and fluorescent lamps for commercial lighting purposes. The enclosed sections deal with some of the properties of xenon lamps relevant to plant illumination; particularly the spectral aspects, the temporal characteristics of the emission, and finally the economy of xenon lamps will be addressed. Due to radiation exceeding the natural global radiation in both the ultraviolet (UV) and the infrared (IR) regions, filter techniques have to be included into the discussion referring to the requirements of plant illumination. Most of the presented results were obtained by investigations in the GSF phytotron or in the closed Phytocell chambers of the University of Erlangen. As our experiences are restricted to area plant illumination rather than spot lights our discussion will concentrate on low pressure long-arc xenon lamps which are commonly used for such plant illuminations. As the spectral properties of short-arc lamps do not differ much from those of long-arc lamps most of our conclusions will be valid for high pressure xenon lamps too. These lamps often serve as light sources for small sun simulators and for monochromators which are used for action spectroscopy of plant responses.

  8. Determining CO2 storage potential during miscible CO2 enhanced oil recovery: Noble gas and stable isotope tracers

    USGS Publications Warehouse

    Shelton, Jenna L.; McIntosh, Jennifer C.; Hunt, Andrew; Beebe, Thomas L; Parker, Andrew D; Warwick, Peter D.; Drake, Ronald; McCray, John E.

    2016-01-01

    Rising atmospheric carbon dioxide (CO2) concentrations are fueling anthropogenic climate change. Geologic sequestration of anthropogenic CO2 in depleted oil reservoirs is one option for reducing CO2 emissions to the atmosphere while enhancing oil recovery. In order to evaluate the feasibility of using enhanced oil recovery (EOR) sites in the United States for permanent CO2 storage, an active multi-stage miscible CO2flooding project in the Permian Basin (North Ward Estes Field, near Wickett, Texas) was investigated. In addition, two major natural CO2 reservoirs in the southeastern Paradox Basin (McElmo Dome and Doe Canyon) were also investigated as they provide CO2 for EOR operations in the Permian Basin. Produced gas and water were collected from three different CO2 flooding phases (with different start dates) within the North Ward Estes Field to evaluate possible CO2 storage mechanisms and amounts of total CO2retention. McElmo Dome and Doe Canyon were sampled for produced gas to determine the noble gas and stable isotope signature of the original injected EOR gas and to confirm the source of this naturally-occurring CO2. As expected, the natural CO2produced from McElmo Dome and Doe Canyon is a mix of mantle and crustal sources. When comparing CO2 injection and production rates for the CO2 floods in the North Ward Estes Field, it appears that CO2 retention in the reservoir decreased over the course of the three injections, retaining 39%, 49% and 61% of the injected CO2 for the 2008, 2010, and 2013 projects, respectively, characteristic of maturing CO2 miscible flood projects. Noble gas isotopic composition of the injected and produced gas for the flood projects suggest no active fractionation, while δ13CCO2 values suggest no active CO2dissolution into formation water, or mineralization. CO2 volumes capable of dissolving in residual formation fluids were also estimated along with the potential to store pure-phase supercritical CO2. Using a combination

  9. Xenon arc lamp spectral radiance modelling for satellite instrument calibration

    NASA Astrophysics Data System (ADS)

    Rolt, Stephen; Clark, Paul; Schmoll, Jürgen; Shaw, Benjamin J. R.

    2016-07-01

    Precise radiometric measurements play a central role in many areas of astronomical and terrestrial observation. We focus on the use of continuum light sources in the absolute radiometric calibration of detectors in an imaging spectrometer for space applications. The application, in this instance, revolves around the ground based calibration of the Sentinel-4/UVN instrument. This imaging spectrometer instrument is expected to be deployed in 2019 and will make spatially resolved spectroscopic measurements of atmospheric chemistry. The instrument, which operates across the UV/VIS and NIR spectrum from 305-775 nm, is designed to measure the absolute spectral radiance of the Earth and compare it with the absolute spectral irradiance of the Sun. Of key importance to the fidelity of these absolute measurements is the ground based calibration campaign. Continuum lamp sources that are temporally stable and are spatially well defined are central to this process. Xenon short arc lamps provide highly intense and efficient continuum illumination in a range extending from the ultra-violet to the infra-red and their spectrum is well matched to this specific application. Despite their widespread commercial use, certain aspects of their performance are not well documented in the literature. One of the important requirements in this calibration application is the delivery of highly uniform, collimated illumination at high radiance. In this process, it cannot be assumed that the xenon arc is a point source; the spatial distribution of the radiance must be characterised accurately. We present here careful measurements that thoroughly characterise the spatial distribution of the spectral radiance of a 1000W xenon lamp. A mathematical model is presented describing the spatial distribution. Temporal stability is another exceptionally important requirement in the calibration process. As such, the paper also describes strategies to re-inforce the temporal stability of the lamp output by

  10. Laser action in xenon pumped by pulsed beams of runaway electrons

    SciTech Connect

    Kolbychev, G.V.; Samyshkin, E.A.

    1983-02-01

    A report is given of the use of pulsed beams of runaway electrons for the pumping of gas lasers. Electron beams were generated inside a laser chamber. The average energy of these electrons was 1--4 keV. Lasing was observed as a result of the 3d/sub 2/--2p/sub 7/ transition in xenon. An analysis was made of the possibility of using runaway-electron beams in other types of gas laser.

  11. Stable isotope dilution gas chromatography-mass spectrometry for quantification of thymoquinone in black cumin seed oil.

    PubMed

    Johnson-Ajinwo, Okiemute Rosa; Li, Wen-Wu

    2014-06-18

    Black cumin seed (Nigella sativa L.) is a widely used spice and herb, where thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone) is the major bioactive compound. Here, a stable isotope dilution (SID) gas chromatography-mass spectrometry (GC-MS) technique was developed for the quantification of thymoquinone. A doubly deuterated thymoquinone ([(2)H2]-thymoquinone) was synthesized for the first time with more than 93% deuteration degree shown by mass spectrometry and proton nuclear magnetic resonance ((1)H NMR). This compound was used as an internal standard for the quantification of thymoquinone using a SID GC-MS method. The validation experiment showed a recovery rate of 99.1 ± 1.1% relative standard deviation (RSD). Standard addition and external calibration methods have also been used to quantify thymoquinone, which cross-validated the developed stable isotope dilution assay (SIDA). In comparison to external calibration and standard addition methods, the SIDA method is robust and accurate. The concentration of thymoquinone in five marketed black cumin seed oils ranged between 3.34 and 10.8 mg/mL by use of SID GC-MS.

  12. Tracing coalbed natural gas-coproduced water using stable isotopes of carbon

    SciTech Connect

    Sharma, S.; Frost, C.D.

    2008-03-15

    Recovery of hydrocarbons commonly is associated with coproduction of water. This water may be put to beneficial use or may be reinjected into subsurface aquifers. In either case, it would be helpful to establish a fingerprint for that coproduced water so that it may be tracked following discharge on the surface or reintroduction to geologic reservoirs. This study explores the potential of using {delta}{sup 13}C of dissolved inorganic carbon (DIC) of coalbed natural gas (CBNG) - coproduced water as a fingerprint of its origin and to trace its fate once it is disposed on the surface. Our initial results for water samples coproduced with CBNG from the Powder River Basin show that this water has strongly positive {delta}{sup 13}C(DIC) (12 parts per thousand to 22 parts per thousand) that is readily distinguished from the negative {delta}{sup 13}C of most surface and ground water (-8 parts per thousand to -11 parts per thousand). Furthermore, the DIC concentrations in coproduced water samples are also high (more than 100 mg C/L) compared to the 20 to 50 mg C/L in ambient surface and ground water of the region. The distinctively high {delta}{sup 13}C and DIC concentrations allow us to identify surface and ground water that have incorporated CBNG-coproduced water. Accordingly, we suggest that the {delta}{sup 13}C(DIC) and DIC concentrations of water can be used for long-term monitoring of infiltration of CBNG-coproduced water into ground water and streams. Our results also show that the {delta} {sup 13}C (DIC) of CBNG-coproduced water from two different coal zones are distinct leading to the possibility of using {delta}{sup 13}C(DIC) to distinguish water produced from different coal zones.

  13. Direct Dark Matter search with XENON100

    NASA Astrophysics Data System (ADS)

    Orrigo, S. E. A.

    2016-07-01

    The XENON100 experiment is the second phase of the XENON program for the direct detection of the dark matter in the universe. The XENON100 detector is a two-phase Time Projection Chamber filled with 161 kg of ultra pure liquid xenon. The results from 224.6 live days of dark matter search with XENON100 are presented. No evidence for dark matter in the form of WIMPs is found, excluding spin-independent WIMP-nucleon scattering cross sections above 2 × 10-45 cm2 for a 55 GeV/c2 WIMP at 90% confidence level (C.L.). The most stringent limit is established on the spin-dependent WIMP-neutron interaction for WIMP masses above 6 GeV/c2, with a minimum cross section of 3.5 × 10-40 cm2 (90% C.L.) for a 45 GeV/c2 WIMP. The same dataset is used to search for axions and axion-like-particles. The best limits to date are set on the axion-electron coupling constant for solar axions, gAe < 7.7 × 10-12 (90% C.L.), and for axion-like-particles, gAe < 1 × 10-12 (90% C.L.) for masses between 5 and 10 keV/c2.

  14. Guidelines and recommended terms for expression of stable-isotope-ratio and gas-ratio measurement results.

    PubMed

    Coplen, Tyler B

    2011-09-15

    To minimize confusion in the expression of measurement results of stable isotope and gas-ratio measurements, recommendations based on publications of the Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) are presented. Whenever feasible, entries are consistent with the Système International d'Unités, the SI (known in English as the International System of Units), and the third edition of the International Vocabulary of Basic and General Terms in Metrology (VIM, 3rd edition). The recommendations presented herein are approved by the Commission on Isotopic Abundances and Atomic Weights and are designed to clarify expression of quantities related to measurement of isotope and gas ratios to ensure that quantity equations instead of numerical value equations are used for quantity definitions. Examples of column headings consistent with quantity calculus (also called the algebra of quantities) and examples of various deprecated usages connected with the terms recommended are presented. Published in 2011 by John Wiley & Sons, Ltd.

  15. Tracing groundwater input into Lake Vanda, Wright Valley, Antarctica using major ions, stable isotopes and noble gas

    NASA Astrophysics Data System (ADS)

    Dowling, C. B.; Poreda, R. J.; Snyder, G. T.

    2008-12-01

    The McMurdo Dry Valleys (MDV), Antarctica, is the largest ice-free region on Antarctica. Lake Vanda, located in central Wright Valley, is the deepest lake among the MDV lakes. It has a relatively fresh water layer above 50 m with a hypersaline calcium-chloride brine below (50-72 m). The Onyx River is the only stream input into Lake Vanda. It flows westward from the coastal Lower Wright Glacier and discharges into Lake Vanda. Suggested by the published literature and this study, there has been and may still be groundwater input into Lake Vanda. Stable isotopes, major ions, and noble gas data from this study coupled with previously published data indicate that the bottom waters of Lake Vanda have had significant contributions from a deep groundwater system. The dissolved gas of the bottom waters of Lake Vanda display solubility concentrations rather than the Ar-enriched dissolved gas seen in the Taylor Valley lakes (such as Lake Bonney). The isotopic data indicate that the bottom calcium-chloride-brine of Lake Vanda has undergone very little evaporation. The calcium-chloride chemistry of the groundwater that discharges into Lake Vanda most likely results from the chemical weathering and dissolution of cryogenic evaporites (antarcticite and gypsum) within the glacial sediments of Wright Valley. The high calcium concentrations of the brine have caused gypsum to precipitate on the lake bottom. Our work also supports previous physical and chemical observations suggesting that the upper portion actively circulates and the hypersaline bottom layer does not. The helium and calcium chloride values are concentrated at the bottom, with a very narrow transition layer between it and the above fresh water. If the freshwater layer did not actively circulate, then diffusion over time would have caused the helium and calcium chloride to slowly permeate upwards through the water column.

  16. Characterisation of NEXT-DEMO using xenon Kα X-rays

    NASA Astrophysics Data System (ADS)

    Lorca, D.; Martín-Albo, J.; Laing, A.; Ferrario, P.; Gómez-Cadenas, J. J.; Álvarez, V.; Borges, F. I. G.; Camargo, M.; Cárcel, S.; Cebrián, S.; Cervera, A.; Conde, C. A. N.; Dafni, T.; Díaz, J.; Esteve, R.; Fernandes, L. M. P.; Ferreira, A. L.; Freitas, E. D. C.; Gehman, V. M.; Goldschmidt, A.; Gómez, H.; González-Díaz, D.; Gutiérrez, R. M.; Hauptman, J.; Hernando Morata, J. A.; Herrera, D. C.; Irastorza, I. G.; Labarga, L.; Liubarsky, I.; Losada, M.; Luzón, G.; Marí, A.; Martínez-Lema, G.; Martínez, A.; Miller, T.; Monrabal, F.; Monserrate, M.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Nygren, D.; Oliveira, C. A. B.; Pérez, J.; Pérez Aparicio, J. L.; Renner, J.; Ripoll, L.; Rodríguez, A.; Rodríguez, J.; Santos, F. P.; dos Santos, J. M. F.; Seguí, L.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.

    2014-10-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence (EL) to amplify the signal from ionization. Understanding the response of the detector is imperative in achieving a consistent and well understood energy measurement. The abundance of xenon K-shell X-ray emission during data taking has been identified as a multitool for the characterisation of the fundamental parameters of the gas as well as the equalisation of the response of the detector. The NEXT-DEMO prototype is a ~ 1.5 kg volume TPC filled with natural xenon. It employs an array of 19 PMTs as an energy plane and of 256 SiPMs as a tracking plane with the TPC light tube and SiPM surfaces being coated with tetraphenyl butadiene (TPB) which acts as a wavelength shifter for the VUV scintillation light produced by xenon. This paper presents the measurement of the properties of the drift of electrons in the TPC, the effects of the EL production region, and the extraction of position dependent correction constants using Kα X-ray deposits. These constants were used to equalise the response of the detector to deposits left by gammas from 22Na.

  17. The neuroprotective effects of xenon and helium in an in vitro model of traumatic brain injury.

    PubMed

    Coburn, Mark; Maze, Mervyn; Franks, Nicholas P

    2008-02-01

    The "inert" gas xenon has been shown to be an effective neuroprotectant in a variety of in vitro and in vivo models of neuronal injury. We examined its neuroprotective properties in an in vitro model of traumatic brain injury. Controlled laboratory study. Academic research laboratory. Organotypic hippocampal brain slices from mice pups. The cultured brain slices were subjected to a focal mechanical trauma, and injury was monitored in the presence and absence of inert gases at normal and elevated pressures and under both normothermic and hypothermic conditions. Neuronal injury was quantified using propidium iodide, which becomes fluorescent only when it enters injured cells. Low pressures of both helium and xenon were effective neuroprotectants when applied in addition to 1 atm of air. Moreover, both gases were effective at normal pressures when they replaced nitrogen in a gas mixture. The inert gases helium and xenon are effective neuroprotectants in a model for traumatic brain injury, and this novel treatment warrants further investigation. Xenon was particularly effective at reducing the secondary injury that developed following the initial trauma and could be administered at least 3 hrs postinjury with only a small reduction in efficacy.

  18. Evaluation of hemodynamic effects of xenon in dogs undergoing hemorrhagic shock.

    PubMed

    Franceschi, Ruben C; Malbouisson, Luiz; Yoshinaga, Eduardo; Auler, Jose Otavio Costa; Figueiredo, Luiz Francisco Poli de; Carmona, Maria Jose C

    2013-01-01

    The anesthetic gas xenon is reported to preserve hemodynamic stability during general anesthesia. However, the effects of the gas during shock are unclear. The objective of this study was to evaluate the effect of Xe on hemodynamic stability and tissue perfusion in a canine model of hemorrhagic shock. Twenty-six dogs, mechanically ventilated with a fraction of inspired oxygen of 21% and anesthetized with etomidate and vecuronium, were randomized into Xenon (Xe; n = 13) or Control (C; n = 13) groups. Following hemodynamic monitoring, a pressure-driven shock was induced to reach an arterial pressure of 40 mmHg. Hemodynamic data and blood samples were collected prior to bleeding, immediately after bleeding and 5, 20 and 40 minutes following shock. The Xe group was treated with 79% Xe diluted in ambient air, inhaled for 20 minutes after shock. The mean bleeding volume was 44 mL.kg-1 in the C group and 40 mL.kg-1 in the Xe group. Hemorrhage promoted a decrease in both the cardiac index (p<0.001) and mean arterial pressure (p<0.001). These changes were associated with an increase in lactate levels and worsening of oxygen transport variables in both groups (p<0.05). Inhalation of xenon did not cause further worsening of hemodynamics or tissue perfusion markers. Xenon did not alter hemodynamic stability or tissue perfusion in an experimentally controlled hemorrhagic shock model. However, further studies are necessary to validate this drug in other contexts.

  19. Simplified Ion Thruster Xenon Feed System for NASA Science Missions

    NASA Technical Reports Server (NTRS)

    Snyder, John Steven; Randolph, Thomas M.; Hofer, Richard R.; Goebel, Dan M.

    2009-01-01

    The successful implementation of ion thruster technology on the Deep Space 1 technology demonstration mission paved the way for its first use on the Dawn science mission, which launched in September 2007. Both Deep Space 1 and Dawn used a "bang-bang" xenon feed system which has proven to be highly successful. This type of feed system, however, is complex with many parts and requires a significant amount of engineering work for architecture changes. A simplified feed system, with fewer parts and less engineering work for architecture changes, is desirable to reduce the feed system cost to future missions. An attractive new path for ion thruster feed systems is based on new components developed by industry in support of commercial applications of electric propulsion systems. For example, since the launch of Deep Space 1 tens of mechanical xenon pressure regulators have successfully flown on commercial spacecraft using electric propulsion. In addition, active proportional flow controllers have flown on the Hall-thruster-equipped Tacsat-2, are flying on the ion thruster GOCE mission, and will fly next year on the Advanced EHF spacecraft. This present paper briefly reviews the Dawn xenon feed system and those implemented on other xenon electric propulsion flight missions. A simplified feed system architecture is presented that is based on assembling flight-qualified components in a manner that will reduce non-recurring engineering associated with propulsion system architecture changes, and is compared to the NASA Dawn standard. The simplified feed system includes, compared to Dawn, passive high-pressure regulation, a reduced part count, reduced complexity due to cross-strapping, and reduced non-recurring engineering work required for feed system changes. A demonstration feed system was assembled using flight-like components and used to operate a laboratory NSTAR-class ion engine. Feed system components integrated into a single-string architecture successfully operated

  20. Simplified Ion Thruster Xenon Feed System for NASA Science Missions

    NASA Technical Reports Server (NTRS)

    Snyder, John Steven; Randolph, Thomas M.; Hofer, Richard R.; Goebel, Dan M.

    2009-01-01

    The successful implementation of ion thruster technology on the Deep Space 1 technology demonstration mission paved the way for its first use on the Dawn science mission, which launched in September 2007. Both Deep Space 1 and Dawn used a "bang-bang" xenon feed system which has proven to be highly successful. This type of feed system, however, is complex with many parts and requires a significant amount of engineering work for architecture changes. A simplified feed system, with fewer parts and less engineering work for architecture changes, is desirable to reduce the feed system cost to future missions. An attractive new path for ion thruster feed systems is based on new components developed by industry in support of commercial applications of electric propulsion systems. For example, since the launch of Deep Space 1 tens of mechanical xenon pressure regulators have successfully flown on commercial spacecraft using electric propulsion. In addition, active proportional flow controllers have flown on the Hall-thruster-equipped Tacsat-2, are flying on the ion thruster GOCE mission, and will fly next year on the Advanced EHF spacecraft. This present paper briefly reviews the Dawn xenon feed system and those implemented on other xenon electric propulsion flight missions. A simplified feed system architecture is presented that is based on assembling flight-qualified components in a manner that will reduce non-recurring engineering associated with propulsion system architecture changes, and is compared to the NASA Dawn standard. The simplified feed system includes, compared to Dawn, passive high-pressure regulation, a reduced part count, reduced complexity due to cross-strapping, and reduced non-recurring engineering work required for feed system changes. A demonstration feed system was assembled using flight-like components and used to operate a laboratory NSTAR-class ion engine. Feed system components integrated into a single-string architecture successfully operated

  1. Reflectance of polytetrafluoroethylene for xenon scintillation light

    SciTech Connect

    Silva, C.; Pinto da Cunha, J.; Pereira, A.; Chepel, V.; Lopes, M. I.; Solovov, V.; Neves, F.

    2010-03-15

    Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet (VUV) wavelength region ({lambda}{approx_equal}175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work, we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived, and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Other fluoropolymers, namely, ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), and perfluoro-alkoxyalkane (PFA) were also measured.

  2. Using stable isotopes of dissolved oxygen for the determination of gas exchange in the Grand River, Ontario, Canada.

    PubMed

    Jamieson, Terra S; Schiff, Sherry L; Taylor, William D

    2013-02-01

    Gas exchange can be a key component of the dissolved oxygen (DO) mass balance in aquatic ecosystems. Quantification of gas transfer rates is essential for the estimation of DO production and consumption rates, and determination of assimilation capacities of systems receiving organic inputs. Currently, the accurate determination of gas transfer rate is a topic of debate in DO modeling, and there are a wide variety of approaches that have been proposed in the literature. The current study investigates the use of repeated measures of stable isotopes of O₂ and DO and a dynamic dual mass-balance model to quantify gas transfer coefficients (k) in the Grand River, Ontario, Canada. Measurements were conducted over a longitudinal gradient that reflected watershed changes from agricultural to urban. Values of k in the Grand River ranged from 3.6 to 8.6 day⁻¹, over discharges ranging from 5.6 to 22.4 m³ s⁻¹, with one high-flow event of 73.1 m³ s⁻¹. The k values were relatively constant over the range of discharge conditions studied. The range in discharge observed in this study is generally representative of non-storm and summer low-flow events; a greater range in k might be observed under a wider range of hydrologic conditions. Overall, k values obtained with the dual model for the Grand River were found to be lower than predicted by the traditional approaches evaluated, highlighting the importance of determining site-specific values of k. The dual mass balance approach provides a more constrained estimate of k than using DO only, and is applicable to large rivers where other approaches would be difficult to use. The addition of an isotopic mass balance provides for a corroboration of the input parameter estimates between the two balances. Constraining the range of potential input values allows for a direct estimate of k in large, productive systems where other k-estimation approaches may be uncertain or logistically infeasible.

  3. A High Resolution Liquid Xenon Imaging Telescope for 0.3-10 MeV Gamma Ray Astrophysics: Construction and Initial Balloon Flights

    NASA Technical Reports Server (NTRS)

    Aprile, Elena

    1993-01-01

    The results achieved with a 3.5 liter liquid xenon time projection chamber (LXe-TPC) prototype during the first year include: the efficiency of detecting the primary scintillation light for event triggering has been measured to be higher than 85%; the charge response has been measured to be stable to within 0.1% for a period of time of about 30 hours; the electron lifetime has been measured to be in excess of 1.3 ms; the energy resolution has been measured to be consistent with previous results obtained with small volume chambers; X-Y gamma ray imaging has been demonstrated with a nondestructive orthogonal wires readout; Monte Carlo simulation results on detection efficiency, expected background count rate at balloon altitude, background reduction algorithms, telescope response to point-like and diffuse sources, and polarization sensitivity calculations; and work on a 10 liter LXe-TPC prototype and gas purification/recovery system.

  4. Xenon contrast CT-CBF scanning of the brain differentiates normal age-related changes from multi-infarct dementia and senile dementia of Alzheimer type

    SciTech Connect

    Tachibana, H.; Meyer, J.S.; Okayasu, H.; Shaw, T.G.; Kandula, P.; Rogers, R.L.

    1984-07-01

    Local cerebral blood flow (LCBF) and partition coefficients (L lambda) were measured during inhalation of stable xenon gas with serial CT scanning among normal volunteers (N . 15), individuals with multi-infarct dementia (MID, N . 10), and persons with senile dementia of Alzheimer type (SDAT, N . 8). Mean gray matter flow values were reduced in both MID and SDAT. Age-related declines in LCBF values in normals were marked in frontal cortex and basal ganglia. LCBF values were decreased beyond normals in frontal and temporal cortices and thalamus in MID and SDAT, in basal ganglia only in MID. Unlike SDAT and age-matched normals, L lambda values were reduced in fronto-temporal cortex and thalamus in MID. Multifocal nature of lesions in MID was apparent. Coefficients of variation for LCBFs were greater in MID compared with SDAT and/or age-matched normals.

  5. Monitoring water stable isotope composition in soils using gas-permeable tubing and infrared laser absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Rothfuss, Youri; Vereecken, Harry; Brüggemann, Nicolas

    2013-04-01

    The water stable isotopologues 1H2H16O and 1H218O are powerful tracers of processes occurring in nature. Their slightly different masses as compared to the most abundant water isotopologue (1H216O) affect their thermodynamic (e.g. during chemical equilibrium reactions or physical phase transitions with equilibration) and kinetic (liquid and vapor phases transport processes and chemical reactions without equilibration) properties. This results in measurable differences of the isotopic composition of water within or between the different terrestrial ecosystem compartments (i.e. sub-soil, soil, surface waters, plant, and atmosphere). These differences can help addressing a number of issues, among them water balance closure and flux partitioning from the soil-plant-atmosphere continuum at the field to regional scales. In soils particularly, the isotopic composition of water (δ2H and δ18O) provides qualitative information about whether water has only infiltrated or already been re-evaporated since the last rainfall event or about the location of the evaporation front. From water stable isotope composition profiles measured in soils, it is also possible, under certain hypotheses, to derive quantitative information such as soil evaporation flux and the identification of root water uptake depths. In addition, water stable isotopologues have been well implemented into physically based Soil-Vegetation-Atmosphere Transfer models (e.g. SiSPAT-Isotope; Soil-Litter iso; TOUGHREACT) and have demonstrated their potential. However, the main disadvantage of the isotope methodology is that, contrary to other soil state variables that can be monitored over long time periods, δ2H and δ18O are typically analyzed following destructive sampling. Here, we present a non-destructive method for monitoring soil liquid water δ2H and δ18O over a wide range of water availability conditions and temperatures by sampling and measuring water vapor equilibrated with soil water using gas

  6. Transdermal diffusion of xenon in vitro using diffusion cells

    NASA Astrophysics Data System (ADS)

    Verkhovsky, A.; Petrov, E.

    2015-11-01

    The aim of this research was to study the diffusion rate of xenon through guinea pig skin and how viscosity of cosmetic component capryl/capric triglyceride (CCT) facilitates to deliver xenon to surface of skin patches. They were placed in Franz cell for 24 hours and diffusion rate and permeability of xenon were calculated. Thus diffusion rate was 0.031 mg/hour*cm2 and permeability was 0.003 cm/hour. Using Brookfield viscometer it was shown that viscosity of CCT decreased upon increasing xenon concentration. Obtained results can be utilized in developing of new xenon containing drugs for topical administration.

  7. The Low-Energy Background in XENON1T

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Stein, Alec; Xenon1T Collaboration

    2017-01-01

    The XENON1T dark matter direct-detection experiment looks for hypothetical Weakly Interacting Massive Particles (WIMPs). WIMPs are expected to scatter off xenon nuclei at low energies, so understanding the low-energy background of the detector is crucial. In XENON1T, the background in the WIMP search region is due to radioactive decays stemming from the detector construction materials and impurities in the xenon itself. We show that our predicted low-energy background rate of 10-4events .kg-1 .day-1 .keV-1 matches XENON1T's design goals and is in agreement with the data taken during the commissioning of the detector.

  8. Multiphoton ionization studies of xenon clusters

    SciTech Connect

    Echt, O.; Cook, M.C.; Castleman, A.W.

    1987-04-03

    Non-resonant multiphoton ionization of xenon clusters has revealed the same magic numbers as found in the case of electron-impact ionization. Large dissociation rates are found for the trimer through pentamer ion, measured on a time scale of approx 10/sup -7/ s after ionization.

  9. DFT-MD simulations of shocked Xenon

    NASA Astrophysics Data System (ADS)

    Magyar, Rudolph J.; Mattsson, Thomas R.

    2009-03-01

    Xenon is not only a technologically important element used in laser technologies, jet propulsion and dental anesthesia, but it is also arguably the simplest material in which to study the metal-insulator transition at high pressure. Because of its closed shell electronic configuration, Xenon is often assumed to be chemically inert, interacting almost entirely through the van der Waals interaction, and at liquid density, is typically modeled well using Leonard-Jones potentials. However, such modeling has a limited range of validity as Xenon is known to form compounds at normal conditions and likely exhibits considerably more chemistry at higher densities when hybridization of occupied orbitals becomes significant. In this talk, we present DFT-MD simulations of shocked liquid Xenon with the goal of developing an improved equation of state. The relative importance of the van der Waals interaction compared to other Coulomb interactions is considered, and estimates of the relative accuracy of various density functionals are quantified. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  10. Gas Wave Bearings: A Stable Alternative to Journal Bearings for High-Speed Oil-Free Machines

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin

    2005-01-01

    To run both smoothly and efficiently, high-speed machines need stable, low-friction bearings to support their rotors. In addition, an oil-free bearing system is a common requirement in today's designs. Therefore, self-acting gas film bearings are becoming the bearing of choice in high-performance rotating machinery, including that used in the machine tool industry. Although plain journal bearings carry more load and have superior lift and land characteristics, they suffer from instability problems. Since 1992, a new type of fluid film bearing, the wave bearing, has been under development at the NASA Lewis Research Center in Cleveland, Ohio, by Dr. Florin Dimofte, a Senior Research Associate of the University of Toledo. One unique characteristic of the waved journal bearing that gives it improved capabilities over conventional journal bearings is the low-amplitude waves of its inner diameter surface. The radial clearance is on the order of one thousandth of the shaft radius, and the wave amplitude is nominally up to one-half the clearance. This bearing concept offers a load capacity which is very close to that of a plain journal bearing, but it runs more stably at nominal speeds.

  11. Quantitative analysis of menthol in human urine using solid phase microextraction and stable isotope dilution gas chromatography-mass spectrometry.

    PubMed

    Huang, Wenlin; Blount, Benjamin C; Watson, Clifford H; Watson, Christina; Chambers, David M

    2017-02-15

    To accurately measure menthol levels in human urine, we developed a method using gas chromatography/electron ionization mass spectrometry with menthol-d4 stable isotope internal standardization. We used solid phase microextraction (SPME) headspace sampling for collection, preconcentration and automation. Conjugated forms of menthol were released using β-glucuronidase/sulfatase to allow for measuring total menthol. Additionally, we processed the specimens without using β-glucuronidase/sulfatase to quantify the levels of unconjugated (free) menthol in urine. This method was developed to verify mentholated cigarette smoking status to study the influence of menthol on smoking behaviour and exposure. This objective was accomplished with this method, which has no carryover or memory from the SPME fiber assembly, a method detection limit of 0.0017μg/mL, a broad linear range of 0.002-0.5μg/mL for free menthol and 0.01-10μg/mL for total menthol, a 7.6% precision and 88.5% accuracy, and an analysis runtime of 17min. We applied this method in analysis of urine specimens collected from cigarette smokers who smoke either mentholated or non-mentholated cigarettes. Among these smokers, the average total urinary menthol levels was three-fold higher (p<0.001) among mentholated cigarette smokers compared with non-mentholated cigarette smokers.

  12. HIGH-SPEED, CLINICAL-SCALE MICROFLUIDIC GENERATION OF STABLE PHASE-CHANGE DROPLETS FOR GAS EMBOLOTHERAPY

    PubMed Central

    Bardin, David; Martz, Thomas D.; Sheeran, Paul S.; Shih, Roger; Dayton, Paul A.; Lee, Abraham P.

    2013-01-01

    In this study we report on a microfluidic device and droplet formation regime capable of generating clinical-scale quantities of droplet emulsions suitable in size and functionality for in vivo therapeutics. By increasing the capillary number – based on the flow rate of the continuous outer phase – in our flow-focusing device, we examine three modes of droplet breakup: geometry-controlled, dripping, and jetting. Operation of our device in the dripping regime results in the generation of highly monodisperse liquid perfluoropentane droplets in the appropriate 3–6 µm range at rates exceeding 105 droplets per second. Based on experimental results relating droplet diameter and the ratio of the continuous and dispersed phase flow rates, we derive a power series equation, valid in the dripping regime, to predict droplet size by Dd ≅ 27(QC/QD)−5/12. The volatile droplets in this study are stable for weeks at room temperature yet undergo rapid liquid-to-gas phase transition, and volume expansion, above a uniform thermal activation threshold. The opportunity exists to potentiate locoregional cancer therapies such as thermal ablation and percutaneous ethanol injection using thermal or acoustic vaporization of these monodisperse phase-change droplets to intentionally occlude the vessels of a cancer. PMID:22011845

  13. Atomistic study of stability of xenon nanoclusters in uranium oxide

    SciTech Connect

    Chartier, A.; Van Brutzel, L.; Freyss, M.

    2010-05-01

    Density-functional theory calculations of the xenon incorporation energies in point defects in urania have been done in order to fit empirical potentials. With this set of parameters, we have considered the incorporation of xenon in small and extended defects such as planar interstitials, grain boundaries, faceted, and spherical voids. The results show that xenon atoms are more likely to aggregate than to be homogeneously distributed in the urania grains. SIGMA5 grain boundary and spherical shape voids are the most favorable defects of xenon atom incorporation. The presence of xenon atoms in nanovoids affects their shape. The energy gain to aggregate xenon atoms into clusters saturates for cluster sizes of about 15-20 Schottky defects. This demonstrates that medium size defects are just as favorable as big size defects for xenon incorporation.

  14. Fumaroles in ice caves on the summit of Mount Rainier—preliminary stable isotope, gas, and geochemical studies

    NASA Astrophysics Data System (ADS)

    Zimbelman, D. R.; Rye, R. O.; Landis, G. P.

    2000-04-01

    The edifice of Mount Rainier, an active stratovolcano, has episodically collapsed leading to major debris flows. The largest debris flows are related to argillically altered rock which leave areas of the edifice prone to failure. The argillic alteration results from the neutralization of acidic magmatic gases that condense in a meteoric water hydrothermal system fed by the melting of a thick mantle of glacial ice. Two craters atop a 2000-year-old cone on the summit of the volcano contain the world's largest volcanic ice-cave system. In the spring of 1997 two active fumaroles (T=62°C) in the caves were sampled for stable isotopic, gas, and geochemical studies. Stable isotope data on fumarole condensates show significant excess deuterium with calculated δD and δ18O values (-234 and -33.2‰, respectively) for the vapor that are consistent with an origin as secondary steam from a shallow water table which has been heated by underlying magmatic-hydrothermal steam. Between 1982 and 1997, δD of the fumarole vapor may have decreased by 30‰. The compositions of fumarole gases vary in time and space but typically consist of air components slightly modified by their solubilities in water and additions of CO2 and CH4. The elevated CO2 contents (δ13CCO2=-11.8±0.7‰), with spikes of over 10,000 ppm, require the episodic addition of magmatic components into the underlying hydrothermal system. Although only traces of H2S were detected in the fumaroles, most notably in a sample which had an air δ13CCO2 signature (-8.8‰), incrustations around a dormant vent containing small amounts of acid sulfate minerals (natroalunite, minamiite, and woodhouseite) indicate higher H2S (or possibly SO2) concentrations in past fumarolic gases. Condensate samples from fumaroles are very dilute, slightly acidic, and enriched in elements observed in the much higher temperature fumaroles at Mount St. Helens (K and Na up to the ppm level; metals such as Al, Pb, Zn Fe and Mn up to the ppb

  15. Fumaroles in ice caves on the summit of Mount Rainier: preliminary stable isotope, gas, and geochemical studies

    USGS Publications Warehouse

    Zimbelman, D.R.; Rye, R.O.; Landis, G.P.

    2000-01-01

    The edifice of Mount Rainier, an active stratovolcano, has episodically collapsed leading to major debris flows. The largest debris flows are related to argillically altered rock which leave areas of the edifice prone to failure. The argillic alteration results from the neutralization of acidic magmatic gases that condense in a meteoric water hydrothermal system fed by the melting of a thick mantle of glacial ice. Two craters atop a 2000-year-old cone on the summit of the volcano contain the world's largest volcanic ice-cave system. In the spring of 1997 two active fumaroles (T=62°C) in the caves were sampled for stable isotopic, gas, and geochemical studies. Stable isotope data on fumarole condensates show significant excess deuterium with calculated δD and δ18O values (−234 and −33.2‰, respectively) for the vapor that are consistent with an origin as secondary steam from a shallow water table which has been heated by underlying magmatic–hydrothermal steam. Between 1982 and 1997, δD of the fumarole vapor may have decreased by 30‰. The compositions of fumarole gases vary in time and space but typically consist of air components slightly modified by their solubilities in water and additions of CO2 and CH4. The elevated CO2 contents δ13CCO2 = -11.8±0.7‰, with spikes of over 10,000 ppm, require the episodic addition of magmatic components into the underlying hydrothermal system. Although only traces of H2S were detected in the fumaroles, most notably in a sample which had an air δ13CCO2 signature (−8.8‰), incrustations around a dormant vent containing small amounts of acid sulfate minerals (natroalunite, minamiite, and woodhouseite) indicate higher H2S (or possibly SO2) concentrations in past fumarolic gases. Condensate samples from fumaroles are very dilute, slightly acidic, and enriched in elements observed in the much higher temperature fumaroles at Mount St. Helens (K and Na up to the ppm level; metals such as Al, Pb, Zn Fe and Mn up to the

  16. Metal-organic framework with optimally selective xenon adsorption and separation.

    PubMed

    Banerjee, Debasis; Simon, Cory M; Plonka, Anna M; Motkuri, Radha K; Liu, Jian; Chen, Xianyin; Smit, Berend; Parise, John B; Haranczyk, Maciej; Thallapally, Praveen K

    2016-06-13

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. The existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal-organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal-organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing.

  17. Metal-organic framework with optimally selective xenon adsorption and separation

    NASA Astrophysics Data System (ADS)

    Banerjee, Debasis; Simon, Cory M.; Plonka, Anna M.; Motkuri, Radha K.; Liu, Jian; Chen, Xianyin; Smit, Berend; Parise, John B.; Haranczyk, Maciej; Thallapally, Praveen K.

    2016-06-01

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. The existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal-organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal-organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing.

  18. Penile xenon (/sup 133/Xe) washout: a rapid method of screening for vasculogenic impotence

    SciTech Connect

    Nseyo, U.O.; Wilbur, H.J.; Kang, S.A.; Flesh, L.; Bennett, A.H.

    1984-01-01

    The radioactive inert gas xenon (/sup 133/Xe) is a well-established isotopic indicator used to assess vascular status in many organ systems. Xenon-133 was used to evaluate male impotence. Xenon-133 was injected subcutaneously at the level of the coronal sulcus in the detumescent state. Using the gamma camera, sequential images were obtained and computer-generated curves calculated. The clearance time for 50 per cent washout of the injected /sup 133/Xe (T1/2) was then calculated for each patient, as well as a control group. Preliminary findings indicate a correlation with such established techniques of evaluating erectile impotence as history, physical examination, penile pulse Doppler tracings, and brachial-penile blood pressure index. The xenon-133 washout study was a rapid, minimally invasive, reproducible, and cost-effective method of screening those impotent patients for vasculogenic etiology of their erectile impotence. We recommend the addition of this method to the surgeon engaged in the care of impotent males.

  19. Xenon NMR: chemical shifts of a general anesthetic in common solvents, proteins, and membranes.

    PubMed Central

    Miller, K W; Reo, N V; Schoot Uiterkamp, A J; Stengle, D P; Stengle, T R; Williamson, K L

    1981-01-01

    The rare gas xenon contains two NMR-sensitive isotopes in high natural abundance. The nuclide 129Xe has a spin of 1/2: 131Xe is quadrupolar with a spin of 3/2. The complementary NMR characteristics of these nuclei provide a unique opportunity for probing their environment. The method is widely applicable because xenon interacts with a useful range of condensed phases including pure liquids, protein solutions, and suspensions of lipid and biological membranes. Although xenon is chemically inert, it does interact with living systems; it is an effective general anesthetic. We have found that the range of chemical shifts of 129Xe dissolved in common solvents is ca. 200 ppm, which is 30 times larger than that found for 13C in methane dissolved in various solvents. Resonances were also observed for 131Xe in some systems; they were broader and exhibited much greater relaxation rates than did 129Xe. The use of 129Xe NMR as a probe of biological systems was investigated. Spectra were obtained from solutions of myoglobin, from suspensions of various lipid bilayers, and from suspensions of the membranes of erythrocytes and of the acetylcholine receptor-rich membranes of Torpedo californica. These systems exhibited a smaller range of chemical shifts. In most cases there was evidence of a fast exchange of xenon between the aqueous and organic environments, but the exchange was slow in suspensions of dimyristoyl lecithin vesicles. PMID:6946442

  20. Hyperpolarized xenon-based molecular sensors for label-free detection of analytes.

    PubMed

    Garimella, Praveena D; Meldrum, Tyler; Witus, Leah S; Smith, Monica; Bajaj, Vikram S; Wemmer, David E; Francis, Matthew B; Pines, Alexander

    2014-01-08

    Nuclear magnetic resonance (NMR) can reveal the chemical constituents of a complex mixture without resorting to chemical modification, separation, or other perturbation. Recently, we and others have developed magnetic resonance agents that report on the presence of dilute analytes by proportionately altering the response of a more abundant or easily detected species, a form of amplification. One example of such a sensing medium is xenon gas, which is chemically inert and can be optically hyperpolarized, a process that enhances its NMR signal by up to 5 orders of magnitude. Here, we use a combinatorial synthetic approach to produce xenon magnetic resonance sensors that respond to small molecule analytes. The sensor responds to the ligand by producing a small chemical shift change in the Xe NMR spectrum. We demonstrate this technique for the dye, Rhodamine 6G, for which we have an independent optical assay to verify binding. We thus demonstrate that specific binding of a small molecule can produce a xenon chemical shift change, suggesting a general approach to the production of xenon sensors targeted to small molecule analytes for in vitro assays or molecular imaging in vivo.

  1. Metal–organic framework with optimally selective xenon adsorption and separation

    SciTech Connect

    Banerjee, Debasis; Simon, Cory M.; Plonka, Anna M.; Motkuri, Radha K.; Liu, Jian; Chen, Xianyin; Smit, Berend; Parise, John B.; Haranczyk, Maciej

    2016-06-13

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. In addition, the existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal–organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal–organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing.

  2. Metal–organic framework with optimally selective xenon adsorption and separation

    DOE PAGES

    Banerjee, Debasis; Simon, Cory M.; Plonka, Anna M.; ...

    2016-06-13

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. In addition, the existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal–organic frameworks have demonstrated the ability to selectively adsorbmore » xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal–organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing.« less

  3. Argon, xenon, hydrogen, and the oxygen consumption and glycolysis of mouse tissue slices.

    PubMed

    SOUTH, F E; COOK, S F

    1954-01-20

    The effects of xenon, argon, and hydrogen on the aerobic and anaerobic metabolism of mouse liver, brain, and sarcoma slices have been investigated. Xenon was found to alter the rates of metabolism of these tissues in a manner almost identical with helium. The gas increased the rate of oxygen consumption in all three tissues and significantly depressed that of anaerobic glycolysis in brain and liver. The depression of glycolysis in sarcoma was less pronounced and not highly significant. Although both the magnitude and statistical significance of the effects observed with argon were much smaller, there was a seeming adherence to the general pattern established by xenon and helium. Hydrogen while remaining essentially ineffective insofar as oxygen uptake was concerned, depressed glycolysis in both liver and brain slices but did not significantly affect sarcoma slices. The following points are stressed in the Discussion: (1) the magnitude and direction of effects exerted by helium, argon, xenon, hydrogen, and nitrogen do not conform with the relative values of molecular weight, density, and solubility of these gases; (2) the effect of these gases on tissue metabolism does not necessarily parallel that exerted upon the whole organism.

  4. Metal–organic framework with optimally selective xenon adsorption and separation

    PubMed Central

    Banerjee, Debasis; Simon, Cory M.; Plonka, Anna M.; Motkuri, Radha K.; Liu, Jian; Chen, Xianyin; Smit, Berend; Parise, John B.; Haranczyk, Maciej; Thallapally, Praveen K.

    2016-01-01

    Nuclear energy is among the most viable alternatives to our current fossil fuel-based energy economy. The mass deployment of nuclear energy as a low-emissions source requires the reprocessing of used nuclear fuel to recover fissile materials and mitigate radioactive waste. A major concern with reprocessing used nuclear fuel is the release of volatile radionuclides such as xenon and krypton that evolve into reprocessing facility off-gas in parts per million concentrations. The existing technology to remove these radioactive noble gases is a costly cryogenic distillation; alternatively, porous materials such as metal–organic frameworks have demonstrated the ability to selectively adsorb xenon and krypton at ambient conditions. Here we carry out a high-throughput computational screening of large databases of metal–organic frameworks and identify SBMOF-1 as the most selective for xenon. We affirm this prediction and report that SBMOF-1 exhibits by far the highest reported xenon adsorption capacity and a remarkable Xe/Kr selectivity under conditions pertinent to nuclear fuel reprocessing. PMID:27291101

  5. Ab initio electron scattering cross-sections and transport in liquid xenon

    NASA Astrophysics Data System (ADS)

    Boyle, G. J.; McEachran, R. P.; Cocks, D. G.; Brunger, M. J.; Buckman, S. J.; Dujko, S.; White, R. D.

    2016-09-01

    Ab initio fully differential cross-sections for electron scattering in liquid xenon are developed from a solution of the Dirac-Fock scattering equations, using a recently developed framework (Boyle et al 2015 J. Chem. Phys. 142 154507) which considers multipole polarizabilities, a non-local treatment of exchange, and screening and coherent scattering effects. A multi-term solution of Boltzmann’s equation accounting for the full anisotropic nature of the differential cross-section is used to calculate transport properties of excess electrons in liquid xenon. The results were found to agree to within 25% of the measured mobilities and characteristic energies over the reduced field range of 10-4-1 Td. The accuracies are comparable to those achieved in the gas phase. A simple model, informed by highly accurate gas-phase cross-sections, is presented to improve the liquid cross-sections, which was found to enhance the accuracy of the transport coefficient calculations.

  6. Demonstration of a transient-gain nickel-like xenon-ion x-ray laser.

    PubMed

    Lu, Peixiang; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kouta; Tanaka, Momoko; Hasegawa, Noboru; Suzuki, Masayuki; Tai, Renzhong; Kado, Masataka; Nagashima, Keisuke; Daido, Hiroyuki; Kato, Yoshiaki; Fiedorowicz, Henryk; Bartnik, Andrzej

    2002-11-01

    We demonstrate a high-gain nickel-like xenon-ion x-ray laser, using a picosecond-laser-irradiated gas-puff target. The elongated x-ray laser plasma column was produced by irradiation of the gas-puff target with line-focused double picosecond laser pulses with a total energy of 18 J in a traveling-wave excitation scheme. Strong lasing at 9.98 nm was observed, and a high gain coefficient of 17.4 cm(-1) was measured on the transient collisionally excited 4d-4p , J=0-1 transition for nickel-like xenon ions with target lengths as great as 0.45 cm. A weak nickel-like lasing line at a shorter wavelength of 9.64 nm was also observed, with a gain coefficient of 5.9 cm(-1) .

  7. Topological signature in the NEXT high pressure xenon TPC

    NASA Astrophysics Data System (ADS)

    Ferrario, Paola; NEXT Collaboration

    2017-09-01

    The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qββ as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 ± 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 ± 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% ± 0.6% background acceptance for 66.9% ± 0.6% signal efficiency.

  8. Multiple-ionization of xenon atoms by positron impact

    NASA Technical Reports Server (NTRS)

    Kruse, Georg; Quermann, Andreas; Raith, Wilhelm; Sinapius, Guenther

    1990-01-01

    Previously the cross sections were measured for positronium formation and single ionization by positron impact for He and H2. With the same apparatus, slightly modified, the single and multiple ionization of xenon is now investigated. The principle of the method is the detection of ion and positron in time correlation which allows the discrimination of positronium formation (whereby the positron vanishes) and the destinction of single, double and triple impact ionization (which lead to different ion flight times from the gas target to the ion detector). By using secondary electrons from the positron moderator, similar measurements were performed on electron impact ionization. By comparing with literature values for electron multiple ionization cross sections, the detection-probability ratios were determined for the differently charged ions.

  9. Stable [Pb(ROH)(N)](2+) complexes in the gas phase: softening the base to match the Lewis acid.

    PubMed

    Akibo-Betts, Glen; Barran, Perdita E; Puskar, Ljiljana; Duncombe, Bridgette; Cox, Hazel; Stace, Anthony J

    2002-08-07

    Experiments have been performed in the gas phase to investigate the stability of complexes of the general form [Pb(ROH)(N)](2+). With water as a solvent, there is no evidence of [Pb(H(2)O)(N)](2+); instead [PbOH(H(2)O)(N-1)](+) is observed, where lead is considered to be held formally in a +2 oxidation state by the formation of a hydroxide core. As the polarizability of the solvating ligands is increased through the use of straight chain alcohols, ROH, solvation of Pb(2+) is observed without proton transfer when R >or= CH(3)CH(2)CH(2)-. The relative stabilities of [Pb(ROH)(4)](2+) complexes with respect to proton transfer are further investigated through the application of density functional theory to examples where R = H, methyl, ethyl, and 1-propyl. Of three trial structures examined for [Pb(ROH)(4)](2+) complexes, in all cases those with the lowest energy comprised of three solvent molecules were directly bound to the central cation, with the fourth molecule held in a secondary shell by hydrogen bonds. The implications of this arrangement as a favorable starting structure for proton transfer are discussed. Conditions for the stability of particular Pb(II)/ligand combinations are also discussed in terms of the hard-soft acid-base principle. Charge population densities calculated for the central lead cation and oxygen donor atoms across the ROH range are used to support the proposal that proton transfer occurs when a ligand is hard. Stability of the [Pb(ROH)(4)](2+) unit is commensurate with a decrease in the ionic character of the bond between Pb(2+) and a ligand; this in turn reflects a softening of the ligand as the alkyl chain increases in length. From the calculations, the most favorable protonated product is, in all cases, (ROH)(2)H(+). The trends observed with lead are compared with Cu(II), which is capable of forming stable gas-phase complexes with water and all of the alcohols considered here.

  10. Segregation in water-based stable single-bubble sonoluminescence.

    PubMed

    Levinsen, Mogens T

    2012-01-01

    A long-standing issue in the field of long-time-stable, water-based, single-bubble sonoluminescence has been the close similarity of the spectra to that of blackbody radiation, the question being whether the similarity is just a weird coincidence, with the bubbles being, on the whole, transparent to their own radiation. One mechanism that has been suggested is the generation of a shock or, at least, a compression wave in the gas of the bubble. A footprint of such a wave would be segregation of species. We have investigated spectra from bubbles seeded with various mixtures of helium or neon with xenon or argon using a transformation, specific to our experimental setup and spectrometer, that was shown to allow for a single-parameter characterization of the spectra in some simpler situations. The surprising result of this investigation is that although no trace of segregation is found, the radiation seems to be highly thermalized in all cases.

  11. Phase behavior of mixed submonolayer films of krypton and xenon on graphite.

    PubMed

    Patrykiejew, A; Sokołowski, S

    2012-04-14

    Using the results of extensive Monte Carlo simulations in the canonical and grand canonical ensembles, we discuss the phase behavior of mixed submonolayer films of krypton and xenon adsorbed on the graphite basal plane. The calculations have been performed using two- and three-dimensional models of the systems studied. It has been demonstrated that out-of-plane motion does not affect the properties of the films as long as the total density is well below the monolayer completion and at moderate temperatures. For the total densities close to the monolayer completion, the promotion of particles to the second layer considerably affects the film properties. Our results are in a reasonable agreement with the available experimental data. The melting point of submonolayer films has been shown to exhibit non-monotonous changes with the film composition, and reaches minimum for the xenon concentration of about 50%. At the temperatures below the melting point, the structure of solid phases depends upon the film composition and the temperature; one can also distinguish commensurate and incommensurate phases. Two-dimensional calculations have demonstrated that for the xenon concentration between about 15% and 65% the adsorbed film exhibits the formation of a superstructure, in which each Xe atom is surrounded by six Kr atoms. This superstructure is stable only at very low temperatures and transforms into the mixed commensurate (√3×√3)R30° phase upon the increase of temperature. Such a superstructure does not appear when a three-dimensional model is used. Grand canonical ensemble calculations allowed us to show that for the xenon concentration of about 3% the phase diagram topology of monolayer films changes from the krypton-like (with incipient triple point) to the xenon-like (with ordinary triple point).

  12. Phase behavior of mixed submonolayer films of krypton and xenon on graphite

    NASA Astrophysics Data System (ADS)

    Patrykiejew, A.; Sokołowski, S.

    2012-04-01

    Using the results of extensive Monte Carlo simulations in the canonical and grand canonical ensembles, we discuss the phase behavior of mixed submonolayer films of krypton and xenon adsorbed on the graphite basal plane. The calculations have been performed using two- and three-dimensional models of the systems studied. It has been demonstrated that out-of-plane motion does not affect the properties of the films as long as the total density is well below the monolayer completion and at moderate temperatures. For the total densities close to the monolayer completion, the promotion of particles to the second layer considerably affects the film properties. Our results are in a reasonable agreement with the available experimental data. The melting point of submonolayer films has been shown to exhibit non-monotonous changes with the film composition, and reaches minimum for the xenon concentration of about 50%. At the temperatures below the melting point, the structure of solid phases depends upon the film composition and the temperature; one can also distinguish commensurate and incommensurate phases. Two-dimensional calculations have demonstrated that for the xenon concentration between about 15% and 65% the adsorbed film exhibits the formation of a superstructure, in which each Xe atom is surrounded by six Kr atoms. This superstructure is stable only at very low temperatures and transforms into the mixed commensurate (√{3}× √{3})R30° phase upon the increase of temperature. Such a superstructure does not appear when a three-dimensional model is used. Grand canonical ensemble calculations allowed us to show that for the xenon concentration of about 3% the phase diagram topology of monolayer films changes from the krypton-like (with incipient triple point) to the xenon-like (with ordinary triple point).

  13. Pathway and energetics of xenon migration in uranium dioxide

    NASA Astrophysics Data System (ADS)

    Thompson, Alexander E.; Wolverton, C.

    2013-03-01

    Using a combination of density functional theory (DFT), classical potentials, molecular dynamics, and nudged elastic band (NEB) calculations, we explore the diffusion of xenon in uranium dioxide (UO2). We compare migration barriers of empirical potentials with DFT by performing NEB calculations and subsequently we use the DFT-validated empirical potentials to calculate vacancy clusters, with and without xenon, to determine the migration path and barrier of xenon in bulk UO2. We find the following: (i) Two empirical potentials out of four tested agree qualitatively with DFT derived energetics for Schottky defect migration; (ii) through the use of molecular dynamics with empirical potentials, we have found a path for the diffusion of xenon-tetravacancy clusters (Xe+2VU+2VO); (iii) this path has an energy barrier significantly lower than previously reported paths by nearly 1 eV; (iv) we examine the physical contributions to the migration pathway and find the barrier is largely electrostatic and that xenon contributes very little to the barrier height; (v) once a uranium vacancy attaches to a xenon-Schottky defect, the resulting xenon-tetravacancy cluster is strongly bound; and (vi) as xenon in a tetravacancy, a xenon-double Schottky defect can diffuse in a concerted manor with a comparable barrier to xenon in a tetravacancy, but two of the oxygen vacancies are only weakly bound to the defect.

  14. Biological variation of the cardiac index in patients with stable chronic heart failure: inert gas rebreathing compared with impedance cardiography†

    PubMed Central

    Täger, Tobias; Fröhlich, Hanna; Franke, Jennifer; Slottje, Karen; Horsch, Andrea; Zdunek, Dietmar; Hess, Georg; Dösch, Andreas; Katus, Hugo A.; Wians, Frank H.

    2015-01-01

    Abstract Aims In chronic heart failure (CHF), changes in cardiac function define the course of the disease. The cardiac index (CI) is the most adequate indicator of cardiac function. Interpretation of serial CI measurements, however, requires knowledge of the biological variation of CI. Because measurements of CI can be confounded by the clinical situation or the method applied, biological variation might be subject to the same confounders. Methods and results We prospectively included 50 CHF patients who met rigid criteria for clinical stability. CI was measured by both inert gas rebreathing (IGR) and impedance cardiography (ICG) in weekly intervals over 3 weeks—each measurement performed at rest (IGRrest/ICGrest) and during low‐exercise 10 Watt pedalling (IGR10W/ICG10W). Intra‐class correlation coefficients (ICCs), reference change values, and minimal important differences of CI were determined for IGRrest, ICGrest, IGR10W, and ICG10W. Impedance cardiography and IGR showed moderate agreement at rest (20% (6–36)) and good agreement at 10 Watt (−4% (−23–16)). Depending on time interval, measurement modality for CI, and mode, ICC ranged between 0.42 and 0.78, ICC values for IGR were lower than those for ICG. Reference change value ranged between 3 and 15%, and minimal important difference ranged between 0.2 and 0.5 L/min/m2. Values for IGR were lower at rest and higher at 10 Watt than those for ICG. Conclusion Non‐invasive measurements of CI are stable over time. Measurement modalities for CI, however, are not interchangeable. Biological variation is less pronounced when obtained by ICG. The influence of low‐level exercise on stability of CI depends on the measurement modality. PMID:27708853

  15. Biological variation of the cardiac index in patients with stable chronic heart failure: inert gas rebreathing compared with impedance cardiography.

    PubMed

    Täger, Tobias; Fröhlich, Hanna; Franke, Jennifer; Slottje, Karen; Horsch, Andrea; Zdunek, Dietmar; Hess, Georg; Dösch, Andreas; Katus, Hugo A; Wians, Frank H; Frankenstein, Lutz

    2015-09-01

    In chronic heart failure (CHF), changes in cardiac function define the course of the disease. The cardiac index (CI) is the most adequate indicator of cardiac function. Interpretation of serial CI measurements, however, requires knowledge of the biological variation of CI. Because measurements of CI can be confounded by the clinical situation or the method applied, biological variation might be subject to the same confounders. We prospectively included 50 CHF patients who met rigid criteria for clinical stability. CI was measured by both inert gas rebreathing (IGR) and impedance cardiography (ICG) in weekly intervals over 3 weeks-each measurement performed at rest (IGRrest/ICGrest) and during low-exercise 10 Watt pedalling (IGR10W/ICG10W). Intra-class correlation coefficients (ICCs), reference change values, and minimal important differences of CI were determined for IGRrest, ICGrest, IGR10W, and ICG10W. Impedance cardiography and IGR showed moderate agreement at rest (20% (6-36)) and good agreement at 10 Watt (-4% (-23-16)). Depending on time interval, measurement modality for CI, and mode, ICC ranged between 0.42 and 0.78, ICC values for IGR were lower than those for ICG. Reference change value ranged between 3 and 15%, and minimal important difference ranged between 0.2 and 0.5 L/min/m(2). Values for IGR were lower at rest and higher at 10 Watt than those for ICG. Non-invasive measurements of CI are stable over time. Measurement modalities for CI, however, are not interchangeable. Biological variation is less pronounced when obtained by ICG. The influence of low-level exercise on stability of CI depends on the measurement modality.

  16. Synthesis and stability of xenon oxides Xe2O5 and Xe3O2 under pressure

    NASA Astrophysics Data System (ADS)

    Dewaele, Agnès; Worth, Nicholas; Pickard, Chris J.; Needs, Richard J.; Pascarelli, Sakura; Mathon, Olivier; Mezouar, Mohamed; Irifune, Tetsuo

    2016-08-01

    The noble gases are the most inert group of the periodic table, but their reactivity increases with pressure. Diamond-anvil-cell experiments and ab initio modelling have been used to investigate a possible direct reaction between xenon and oxygen at high pressures. We have now synthesized two oxides below 100 GPa (Xe2O5 under oxygen-rich conditions, and Xe3O2 under oxygen-poor conditions), which shows that xenon is more reactive under pressure than predicted previously. Xe2O5 was observed using X-ray diffraction methods, its structure identified through ab initio random structure searching and confirmed using X-ray absorption and Raman spectroscopies. The experiments confirm the recent prediction of Xe3O2 as a stable xenon oxide under high pressure. Xenon atoms adopt mixed oxidation states of 0 and +4 in Xe3O2 and +4 and +6 in Xe2O5. Xe3O2 and Xe2O5 form extended networks that incorporate oxygen-sharing XeO4 squares, and Xe2O5 additionally incorporates oxygen-sharing XeO5 pyramids. Other xenon oxides (XeO2, XeO3) are expected to form at higher pressures.

  17. Synthesis and stability of xenon oxides Xe2O5 and Xe3O2 under pressure.

    PubMed

    Dewaele, Agnès; Worth, Nicholas; Pickard, Chris J; Needs, Richard J; Pascarelli, Sakura; Mathon, Olivier; Mezouar, Mohamed; Irifune, Tetsuo

    2016-08-01

    The noble gases are the most inert group of the periodic table, but their reactivity increases with pressure. Diamond-anvil-cell experiments and ab initio modelling have been used to investigate a possible direct reaction between xenon and oxygen at high pressures. We have now synthesized two oxides below 100 GPa (Xe2O5 under oxygen-rich conditions, and Xe3O2 under oxygen-poor conditions), which shows that xenon is more reactive under pressure than predicted previously. Xe2O5 was observed using X-ray diffraction methods, its structure identified through ab initio random structure searching and confirmed using X-ray absorption and Raman spectroscopies. The experiments confirm the recent prediction of Xe3O2 as a stable xenon oxide under high pressure. Xenon atoms adopt mixed oxidation states of 0 and +4 in Xe3O2 and +4 and +6 in Xe2O5. Xe3O2 and Xe2O5 form extended networks that incorporate oxygen-sharing XeO4 squares, and Xe2O5 additionally incorporates oxygen-sharing XeO5 pyramids. Other xenon oxides (XeO2, XeO3) are expected to form at higher pressures.

  18. Pairwise additivity in the nuclear magnetic resonance interactions of atomic xenon.

    PubMed

    Hanni, Matti; Lantto, Perttu; Vaara, Juha

    2009-04-14

    Nuclear magnetic resonance (NMR) of atomic (129/131)Xe is used as a versatile probe of the structure and dynamics of various host materials, due to the sensitivity of the Xe NMR parameters to intermolecular interactions. The principles governing this sensitivity can be investigated using the prototypic system of interacting Xe atoms. In the pairwise additive approximation (PAA), the binary NMR chemical shift, nuclear quadrupole coupling (NQC), and spin-rotation (SR) curves for the xenon dimer are utilized for fast and efficient evaluation of the corresponding NMR tensors in small xenon clusters Xe(n) (n = 2-12). If accurate, the preparametrized PAA enables the analysis of the NMR properties of xenon clusters, condensed xenon phases, and xenon gas without having to resort to electronic structure calculations of instantaneous configurations for n > 2. The binary parameters for Xe(2) at different internuclear distances were obtained at the nonrelativistic Hartree-Fock level of theory. Quantum-chemical (QC) calculations at the corresponding level were used to obtain the NMR parameters of the Xe(n) (n = 2-12) clusters at the equilibrium geometries. Comparison of PAA and QC data indicates that the direct use of the binary property curves of Xe(2) can be expected to be well-suited for the analysis of Xe NMR in the gaseous phase dominated by binary collisions. For use in condensed phases where many-body effects should be considered, effective binary property functions were fitted using the principal components of QC tensors from Xe(n) clusters. Particularly, the chemical shift in Xe(n) is strikingly well-described by the effective PAA. The coordination number Z of the Xe site is found to be the most important factor determining the chemical shift, with the largest shifts being found for high-symmetry sites with the largest Z. This is rationalized in terms of the density of virtual electronic states available for response to magnetic perturbations.

  19. Xenon ion propulsion for orbit transfer

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.; Patterson, M. J.; Gruber, R. P.

    1990-01-01

    The status of critical ion propulsion system elements is reviewed. Electron bombardment ion thrusters for primary propulsion have evolved to operate on xenon in the 5-10 kW power range. Thruster efficiencies of 0.7 and specific impulse values of 4000 s have been documented. The baseline thruster currently under development by NASA LeRC includes ring-cusp magnetic field plasma containment and dished two-grid ion optics. Based on past experience and demonstrated simplifications, power processors for these thrusters should have approximately 500 parts, a mass of 40 kg, and an efficiency near 0.94. Thrust vector control, via individual thruster gimbals, is a mature technology. High pressure, gaseous xenon propellant storage and control schemes, using flight qualified hardware, result in propellant tankage fractions between 0.1 and 0.2. In-space and ground integration testing has demonstrated that ion propulsion systems can be successfully integrated with their host spacecraft.

  20. Optimization of Xenon Biosensors for Detection of ProteinInteractions

    SciTech Connect

    Lowery, Thomas J.; Garcia, Sandra; Chavez, Lana; Ruiz, E.Janette; Wu, Tom; Brotin, Thierry; Dutasta, Jean-Pierre; King, David S.; Schultz, Peter G.; Pines, Alex; Wemmer, David E..

    2005-08-03

    Hyperpolarized 129Xe NMR can detect the presence of specific low-concentration biomolecular analytes by means of the xenon biosensor, which consists of a water-soluble, targeted cryptophane-A cage that encapsulates xenon. In this work we use the prototypical biotinylated xenon biosensor to determine the relationship between the molecular composition of the xenon biosensor and the characteristics of protein-bound resonances. The effects of diastereomer overlap, dipole-dipole coupling, chemical shift anisotropy, xenon exchange, and biosensor conformational exchange on protein-bound biosensor signal were assessed. It was found that optimal protein-bound biosensor signal can be obtained by minimizing the number of biosensor diastereomers and using a flexible linker of appropriate length. Both the linewidth and sensitivity of chemical shift to protein binding of the xenon biosensor were found to be inversely proportional to linker length.

  1. Port and harbor patrol car loaded Xenon search light

    NASA Astrophysics Data System (ADS)

    Amoh, Hiroshi; Takenami, Takashi

    2005-05-01

    The container ship yard is brighten by the lighting, but after Sunset of the sea side is dark during a crescent. On the sea side lighting, we propose to use to patrol car loaded Xenon search light. Generally, the Pacific Ocean of a surface of the sea swimming fishes such as Samma (Mackerel pike) likes strong visible light as a Xenon search light beam. In the feeling of the human eyes and brains with a strong visible light beam such as Xenon search light, the reaction is divided two kind of types, to avoid reaction's humans have a feeling that bad conscience, and no reaction's humans tend to have a feeling of good mind. For the black painted unmanned objects of visible watching is needed as possible as strong visible light beam of the Xenon search light. The optical system of the Xenon search light consists of a Xenon lamp, a parabolic mirror and the filters.

  2. Boiling heat transfer characteristics of liquid xenon

    NASA Astrophysics Data System (ADS)

    Haruyama, T.

    2002-05-01

    Liquid xenon is one of the excellent media for high-energy particle calorimeter. In order to detect a scintillation light effectively, a large number of photo-multipliers (PMTs) will be immersed in liquid xenon. Many chip-resistors equipped with the PMTs dissipate heat into liquid and possibly generate thermal turbulence, such as bubbles, convection flow under a certain operating condition. There is, however, no heat transfer curve (q-ΔT curve) in the literature. Boiling heat transfer characteristics of liquid xenon were measured at a saturated pressure of 0.1 MPa for the first time by using a small pulse tube refrigerator. The heat transfer surface is a thin platinum wire of 0.1 mm diameter and 25 mm long. The measured results were in good agreement with the calculated values both in natural convection and nucleate boiling condition. The film boiling state was difficult to obtain due to its poor reproducibility, and only one data was obtained. The relationship between the heat flux q and temperature difference ΔT was in good agreement with the Morgan's empirical equation in the natural convection region, and with the Kutateladze's equation in the nucleate boiling region.

  3. Response of liquid xenon to low-energy ionizing radiation and its use in the XENON10 dark matter search

    NASA Astrophysics Data System (ADS)

    Manalaysay, Aaron Gosta

    higher energy recoils we measure a value of 0.21, consistent with previously reported data. In light of this new measurement, the XENON10 experiment's upper limits on spin-independent WIMP-nucleon cross section, which were calculated assuming a constant 0.19 relative scintillation efficiency, change from 8.8 x 10-44 cm2 to 9.9 x 10-44 cm2 for WIMPs of mass 100 GeV/c2, and from 4.5 x 10-44 cm2 to 5.6 x 10-44 cm2 for WIMPs of mass 30 GeV/ c2. In Chapter 6, I highlight the fact that a difficult task with many particle detectors focusing on interactions below ˜100 keV is to perform a calibration in the appropriate energy range that adequately probes all regions of the detector. Because detector response can vary greatly in various locations within the device, a spatially uniform calibration is important. A new method for calibration of liquid xenon (LXe) detectors is presented, using the short-lived 83mKr. This source has transitions at 9.4 and 32.1 keV, and as a noble gas like Xe, it disperses uniformly in all regions of the detector. Even for low source activities, the existence of the two transitions provides a method of identifying the decays that is free of background. At decreasing energies, the LXe light yield increases, while the amount of electric field quenching is diminished. Additionally, if any long-lived radioactive backgrounds are introduced by this method, it is shown that they will present less than 67x10 -6 events kg-1 day-1 keV-1 of background in the next generation of LXe dark matter direct detection searches. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  4. Relaxation channels of multi-photon excited xenon clusters

    SciTech Connect

    Serdobintsev, P. Yu.; Melnikov, A. S.; Rakcheeva, L. P. Murashov, S. V.; Khodorkovskii, M. A.; Lyubchik, S.; Timofeev, N. A.; Pastor, A. A.

    2015-09-21

    The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

  5. Relaxation channels of multi-photon excited xenon clusters.

    PubMed

    Serdobintsev, P Yu; Rakcheeva, L P; Murashov, S V; Melnikov, A S; Lyubchik, S; Timofeev, N A; Pastor, A A; Khodorkovskii, M A

    2015-09-21

    The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

  6. Relaxation channels of multi-photon excited xenon clusters

    NASA Astrophysics Data System (ADS)

    Serdobintsev, P. Yu.; Rakcheeva, L. P.; Murashov, S. V.; Melnikov, A. S.; Lyubchik, S.; Timofeev, N. A.; Pastor, A. A.; Khodorkovskii, M. A.

    2015-09-01

    The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

  7. Identification of stable cytotoxic factors in the gas phase extract of cigarette smoke and pharmacological characterization of their cytotoxicity.

    PubMed

    Noya, Yoichi; Seki, Koh-Ichi; Asano, Hiroshi; Mai, Yosuke; Horinouchi, Takahiro; Higashi, Tsunehito; Terada, Koji; Hatate, Chizuru; Hoshi, Akimasa; Nepal, Prabha; Horiguchi, Mika; Kuge, Yuji; Miwa, Soichi

    2013-12-06

    Smoking is a major risk factor for atherosclerotic vascular diseases, but the mechanism for its genesis is unknown. We have recently shown that the gas phase of cigarette smoke (nicotine- and tar-free cigarette smoke extract; CSE) likely to reach the systemic circulation contains stable substances which cause cytotoxicity like plasma membrane damage and cell death in cultured cells, and also that the plasma membrane damage is caused through sequential activation of protein kinase C (PKC) and NADPH oxidase (NOX) and the resulting generation of reactive oxygen species (PKC/NOX-dependent mechanism), whereas cell death is caused through PKC/NOX-dependent and -independent mechanisms. To identify these stable substances, the CSE was prepared by passing the main-stream smoke of 10 cigarettes through a Cambridge glass fiber filter, trapping of the smoke in a vessel cooled at -80°C, and subsequent dissolution in 10ml of water. The CSE was fractionated into nine fractions using reversed-phase HPLC, and each fraction was screened for cytotoxicity in cultured cells, using propidium iodide uptake assay for cell membrane damage and MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] reduction assay for cell viability. The cytotoxicity was positive in two of the nine fractions (Fr2 and Fr5). After extraction of the active fractions into dichloromethane, GC/MS analysis identified 2-cyclopenten-1-one (CPO) in Fr5 but none in Fr2. After derivatization of the active fractions with O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride, GC/MS analysis identified acrolein, acetone and propionaldehyde in Fr2, and methyl vinyl ketone (MVK) in Fr5. After 4-h incubation, authentic acrolein and MVK induced concentration-dependent cytotoxicity with EC50 values of 75.9±8.2 and 47.0±8.0μM (mean±SEM; n=3), respectively, whereas acetone, propionaldehyde and CPO were without effect. However, after 24-h incubation, CPO induced concentration

  8. A hydrogen gas-water equilibration method produces accurate and precise stable hydrogen isotope ratio measurements in nutrition studies

    USDA-ARS?s Scientific Manuscript database

    Stable hydrogen isotope methodology is used in nutrition studies to measure growth, breast milk intake, and energy requirement. Isotope ratio MS is the best instrumentation to measure the stable hydrogen isotope ratios in physiological fluids. Conventional methods to convert physiological fluids to ...

  9. Mutually supportive use of stable isotope and gas chromatography techniques to understand ecohydrological interactions in dryland environments

    NASA Astrophysics Data System (ADS)

    Puttock, A.; Brazier, R. E.; Dungait, J. A. J.; Bol, R.; Dixon, E. R.; Macleod, C. J. A.

    2012-04-01

    Many drylands globally are experiencing extensive vegetation change. In the semi-arid Southwestern United States, this change is characterised by the encroachment of woody vegetation into environments previously dominated by grassland (Van Auken. 2009). The transition from grass to woody vegetation results in a change in ecosystem structure and function (Turnbull et al. 2008). Structural change is typically characterised by an increased heterogeneity of soil and vegetation resources, associated with reduced vegetation coverage and an increased vulnerability to soil erosion and the potential loss of key nutrients to adjacent fluvial systems. This project uses an ecohydrological approach, monitoring natural rainfall-runoff events and resulting water and sediment fluxes over six bounded plots with different vegetation coverage at the Sevilleta National Wildlife Refuge, New Mexico, USA. The experiment takes advantage of a shift in the photosynthetic pathway of dominant vegetation from C3 piñon-juniper (Pinus edulis-Juniperus monosperma) mixed stand through a C4 pure-grass (Bouteloua eriopoda) to C3 shrub (Larrea tridentate). This allows for the utilisation of natural abundance tracing techniques, specifically stable 13C isotope and gas chromatography lipid biomarker analyses. Results collected during the 2010 and 2011 monsoon seasons will be presented, using biogeochemical signatures, to trace and partition fluvial soil organic matter and carbon fluxes during runoff generating rainfall events. Results show that biogeochemical signatures specific to individual plant species can be used to define the provenance of carbon, quantifying whether more Pinus edulis-Juniperus monosperma derived carbon is mobilised from the upland plots, or whether more Larrea tridentata carbon is lost when compared to bouteloa eripoda losses in the lowlands. Results also show that biogeochemical signatures vary with event characteristics, raising the possibility of using these tracing

  10. Low-temperature, highly selective, gas-phase oxidation of benzyl alcohol over mesoporous K-Cu-TiO2 with stable copper(I) oxidation state.

    PubMed

    Fan, Jie; Dai, Yihu; Li, Yunlong; Zheng, Nanfeng; Guo, Junfang; Yan, Xiaoqing; Stucky, Galen D

    2009-11-04

    A newly developed mesoporous mixed metal oxide (K-Cu-TiO(2)) catalyst is capable of highly selective, gas-phase benzyl alcoholbenzaldehyde transformation at excellent yields (>99%) under surprisingly low temperatures (203 degrees C, bp of benzyl alcohol). The low-temperature reaction conditions and integration of K and Cu(I) components into the TiO(2) matrix are of vital importance for the stabilization of an active Cu(I) oxidation state and resultant stable, excellent catalytic performance.

  11. Excimer emission from pulsed microhollow cathode discharges in xenon

    SciTech Connect

    Lee, B.-J.; Nam, S. H.; Rahaman, H.; Iberler, M.; Jacoby, J.; Frank, K.

    2013-12-15

    Direct current (dc) microhollow cathode discharge (MHCD) is an intense source for excimer radiation in vacuum ultraviolet at a wavelength of 172 nm in a high pressure xenon (Xe) gas. The concentration of precursors for the excimer formation, i.e., excited and ionized gas atoms, increases significantly by applying high voltage pulse onto the dc MHCD over the pulse duration range from 20 to 100 ns. The intensity of the excimer emission for the voltage pulse of 20 ns duration exceeds that of the emission intensity obtained from the same MHCD operated only in the dc mode, by one order of magnitude. In addition, the emission intensity increases by one order of magnitude over the pulse duration range from 20 to 100 ns. It can be assumed that the emission intensity of the MHCD source increases as long as the duration of the high voltage pulse is shorter than the electron relaxation time. For the high voltage pulse of 100 ns duration, the emission intensity has been found to be further enhanced by a factor of three when the gas pressure is increased from 200 to 800 mbar.

  12. Xenon Recovery at Room Temperature using Metal-Organic Frameworks.

    PubMed

    Elsaidi, Sameh K; Ongari, Daniele; Xu, Wenqian; Mohamed, Mona H; Haranczyk, Maciej; Thallapally, Praveen K

    2017-08-10

    Xenon is known to be a very efficient anesthetic gas, but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycling from anesthetic gas mixtures can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low-temperature distillation to recover Xe; this method is expensive to use in medical facilities. Herein, we propose a much simpler and more efficient system to recover and recycle Xe from exhaled anesthetic gas mixtures at room temperature using metal-organic frameworks (MOFs). Among the MOFs tested, PCN-12 exhibits unprecedented performance with high Xe capacity and Xe/O2 , Xe/N2 and Xe/CO2 selectivity at room temperature. The in situ synchrotron measurements suggest that Xe is occupies the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Xenon Recovery at Room Temperature using Metal Organic Frameworks

    SciTech Connect

    Elsaidi, Sameh K.; Ongari, Daniele; Xu, Wenqian; Mohamed, Mona H.; Haranczyk, Maciej; Thallapally, Praveen K.

    2017-01-01

    Xenon is known to be a very efficient anesthetic gas but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycle from anesthetic gas mixture can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low temperature distillation to recover Xe, which is expensive to use in medical facilities. Herein, we propose much efficient and simpler system to recover and recycle Xe from simulant exhale anesthetic gas mixture at room temperature using metal organic frameworks. Among the MOFs tested, PCN-12 exhibits unprecedented performance with high Xe capacity, Xe/O2, Xe/N2 and Xe/CO2 selectivity at room temperature. The in-situ synchrotron measurements suggest the Xe is occupied in the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12.

  14. High-Rydberg Xenon Submillimeter-Wave Detector

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara

    1987-01-01

    Proposed detector for infrared and submillimeter-wavelength radiation uses excited xenon atoms as Rydberg sensors instead of customary beams of sodium, potassium, or cesium. Chemically inert xenon easily stored in pressurized containers, whereas beams of dangerously reactive alkali metals must be generated in cumbersome, unreliable ovens. Xenon-based detector potential for infrared astronomy and for Earth-orbiter detection of terrestrial radiation sources. Xenon atoms excited to high energy states in two stages. Doubly excited atoms sensitive to photons in submillimeter wavelength range, further excited by these photons, then ionized and counted.

  15. Liquid xenon detectors for particle physics and astrophysics

    SciTech Connect

    Aprile, E.; Doke, T.

    2010-07-15

    This article reviews the progress made over the last 20 years in the development and applications of liquid xenon detectors in particle physics, astrophysics, and medical imaging experiments. A summary of the fundamental properties of liquid xenon as radiation detection medium, in light of the most current theoretical and experimental information is first provided. After an introduction of the different type of liquid xenon detectors, a review of past, current, and future experiments using liquid xenon to search for rare processes and to image radiation in space and in medicine is given. Each application is introduced with a survey of the underlying scientific motivation and experimental requirements before reviewing the basic characteristics and expected performance of each experiment. Within this decade it appears likely that large volume liquid xenon detectors operated in different modes will contribute to answering some of the most fundamental questions in particle physics, astrophysics, and cosmology, fulfilling the most demanding detection challenges. From detectors based solely on liquid xenon (LXe) scintillation, such as in the MEG experiment for the search of the rare ''{mu}{yields}e{gamma}'' decay, currently the largest liquid xenon detector in operation, and in the XMASS experiment for dark matter detection, to the class of time projection chambers which exploit both scintillation and ionization of LXe, such as in the XENON dark matter search experiment and in the Enriched Xenon Observatory for neutrinoless double beta decay, unrivaled performance and important contributions to physics in the next few years are anticipated.

  16. Xenon preconditioning reduces brain damage from neonatal asphyxia in rats.

    PubMed

    Ma, Daqing; Hossain, Mahmuda; Pettet, Garry K J; Luo, Yan; Lim, Ta; Akimov, Stanislav; Sanders, Robert D; Franks, Nicholas P; Maze, Mervyn

    2006-02-01

    Xenon attenuates on-going neuronal injury in both in vitro and in vivo models of hypoxic-ischaemic injury when administered during and after the insult. In the present study, we sought to investigate whether the neuroprotective efficacy of xenon can be observed when administered before an insult, referred to as 'preconditioning'. In a neuronal-glial cell coculture, preexposure to xenon for 2 h caused a concentration-dependent reduction of lactate dehydrogenase release from cells deprived of oxygen and glucose 24 h later; xenon's preconditioning effect was abolished by cycloheximide, a protein synthesis inhibitor. Preconditioning with xenon decreased propidium iodide staining in a hippocampal slice culture model subjected to oxygen and glucose deprivation. In an in vivo model of neonatal asphyxia involving hypoxic-ischaemic injury to 7-day-old rats, preconditioning with xenon reduced infarction size when assessed 7 days after injury. Furthermore, a sustained improvement in neurologic function was also evident 30 days after injury. Phosphorylated cAMP (cyclic adenosine 3',5'-monophosphate)-response element binding protein (pCREB) was increased by xenon exposure. Also, the prosurvival proteins Bcl-2 and brain-derived neurotrophic factor were upregulated by xenon treatment. These studies provide evidence for xenon's preconditioning effect, which might be caused by a pCREB-regulated synthesis of proteins that promote survival against neuronal injury.

  17. Adsorption of xenon on vicinal copper and platinum surfaces

    NASA Astrophysics Data System (ADS)

    Baker, Layton

    The adsorption of xenon was studied on Cu(111), Cu(221), Cu(643) and on Pt(111), Pt(221), and Pt(531) using low energy electron diffraction (LEED), temperature programmed desorption (TPD) of xenon, and ultraviolet photoemission of adsorbed xenon (PAX). These experiments were performed to study the atomic and electronic structure of stepped and step-kinked, chiral metal surfaces. Xenon TPD and PAX were performed on each surface in an attempt to titrate terrace, step edge, and kink adsorption sites by adsorption energetics (TPD) and local work function differences (PAX). Due to the complex behavior of xenon on the vicinal copper and platinum metal surfaces, adsorption sites on these surfaces could not be adequately titrated by xenon TPD. On Cu(221) and Cu(643), xenon desorption from step adsorption sites was not apparent leading to the conclusion that the energy difference between terrace and step adsorption is minuscule. On Pt(221) and Pt(531), xenon TPD indicated that xenon prefers to bond at step edges and that the xenon-xenon interaction at step edges in repulsive but no further indication of step-kink adsorption was observed. The Pt(221) and Pt(531) TPD spectra indicated that the xenon overlayer undergoes strong compression near monolayer coverage on these surfaces due to repulsion between step-edge adsorbed xenon and other encroaching xenon atoms. The PAX experiments on the copper and platinum surfaces demonstrated that the step adsorption sites have lower local work functions than terrace adsorption sites and that higher step density leads to a larger separation in the local work function of terrace and step adsorption sites. The PAX spectra also indicated that, for all surfaces studied at 50--70 K, step adsorption is favored at low coverage but the step sites are not saturated until monolayer coverage is reached; this observation is due to the large entropy difference between terrace and step adsorption states and to repulsive interactions between xenon atoms

  18. UTEX modeling of xenon signature sensitivity to geology and explosion cavity characteristics following an underground nuclear explosion

    NASA Astrophysics Data System (ADS)

    Lowrey, J. D.; Haas, D.

    2013-12-01

    Underground nuclear explosions (UNEs) produce anthropogenic isotopes that can potentially be used in the verification component of the Comprehensive Nuclear-Test-Ban Treaty. Several isotopes of radioactive xenon gas have been identified as radionuclides of interest within the International Monitoring System (IMS) and in an On-Site Inspection (OSI). Substantial research has been previously undertaken to characterize the geologic and atmospheric mechanisms that can drive the movement of radionuclide gas from a well-contained UNE, considering both sensitivities on gas arrival time and signature variability of xenon due to the nature of subsurface transport. This work further considers sensitivities of radioxenon gas arrival time and signatures to large variability in geologic stratification and generalized explosion cavity characteristics, as well as compares this influence to variability in the shallow surface.

  19. Theoretical ab initio study of Xenon pentafluoride anion. Mechanism of Xenon pseudorotation

    NASA Astrophysics Data System (ADS)

    Fleurat-Lessard, Paul; Durupthy, Olivier; Volatron, François

    2002-09-01

    Ab initio calculations have been performed on XeF 5- anion at the MP2 and CCSD(T) levels with a large basis set. Four extrema have been optimized and characterized by frequencies analysis. We find the absolute minimum to be of D 5h symmetry in accordance with the experimental data; the theoretical vibrational spectrum of this minimum is in good agreement with the experimental one. Three other extrema are found to be higher in energy depending on the angular separation of the Xenon lone pairs as predicted by the VSEPR theory. Finally the characterized transition state has been found to belong to the Xenon pseudorotation pathway.

  20. Quantifying the relative contribution of natural gas fugitive emissions to total methane emissions in Colorado and Utah using mobile stable isotope (13CH4) analysis

    NASA Astrophysics Data System (ADS)

    Rella, Chris; Jacobson, Gloria; Crosson, Eric; Karion, Anna; Petron, Gabrielle; Sweeney, Colm

    2013-04-01

    Fugitive emissions of methane into the atmosphere are a major concern facing the natural gas production industry. Because methane is more energy-rich than coal per kg of CO2 emitted into the atmosphere, it represents an attractive alternative to coal for electricity generation. However, given that the global warming potential of methane is many times greater than that of carbon dioxide (Solomon et al. 2007), the importance of quantifying the fugitive emissions of methane throughout the natural gas production and distribution process becomes clear (Howarth et al. 2011). A key step in the process of assessing the emissions arising from natural gas production activities is partitioning the observed methane emissions between natural gas fugitive emissions and other sources of methane, such as from landfills or agricultural activities. One effective method for assessing the contribution of these different sources is stable isotope analysis. In particular, the 13CH4 signature of natural gas (-35 to -40 permil) is significantly different that the signature of other significant sources of methane, such as landfills or ruminants (-45 to -70 permil). In this paper we present measurements of mobile field 13CH4 using a spectroscopic stable isotope analyzer based on cavity ringdown spectroscopy, in two intense natural gas producing regions of the United States: the Denver-Julesburg basin in Colorado, and the Uintah basin in Utah. Mobile isotope measurements in the nocturnal boundary layer have been made, over a total path of 100s of km throughout the regions, allowing spatially resolved measurements of the regional isotope signature. Secondly, this analyzer was used to quantify the isotopic signature of those individual sources (natural gas fugitive emissions, concentrated animal feeding operations, and landfills) that constitute the majority of methane emissions in these regions, by making measurements of the isotope ratio directly in the downwind plume from each source. These

  1. Method for the simultaneous preparation of Radon-211, Xenon-125, Xenon-123, Astatine-211, Iodine-125 and Iodine-123

    DOEpatents

    Mirzadeh, Saed; Lambrecht, Richard M.

    1987-01-01

    A method for simultaneously preparing Radon-211, Astatine-211, Xenon-125, Xenon-123, Iodine-125 and Iodine-123 in a process that includes irradiating a fertile metal material then using a one-step chemical procedure to collect a first mixture of about equal amounts of Radon-211 and Xenon-125, and a separate second mixture of about equal amounts of Iodine-123 and Astatine-211.

  2. Xenon migration in UO2 under irradiation studied by SIMS profilometry

    NASA Astrophysics Data System (ADS)

    Marchand, B.; Moncoffre, N.; Pipon, Y.; Bérerd, N.; Garnier, C.; Raimbault, L.; Sainsot, P.; Epicier, T.; Delafoy, C.; Fraczkiewicz, M.; Gaillard, C.; Toulhoat, N.; Perrat-Mabilon, A.; Peaucelle, C.

    2013-09-01

    During Pressurized Water Reactor operation, around 25% of the created Fission Products (FP) are Xenon and Krypton. They have a low solubility in the nuclear fuel and can either (i) agglomerate into bubbles which induce mechanical stress in the fuel pellets or (ii) be released from the pellets, increasing the pressure within the cladding and decreasing the thermal conductivity of the gap between pellets and cladding. After fifty years of studies on the nuclear fuel, all mechanisms of Fission Gas Release (FGR) are still not fully understood. This paper aims at studying the FGR mechanisms by decoupling thermal and irradiation effects and by assessing the Xenon behavior for the first time by profilometry. Samples are first implanted with 136Xe at 800 keV corresponding to a projected range of 140 nm. They are then either annealed in the temperature range 1400-1600 °C, or irradiated with heavy energy ions (182 MeV Iodine) at Room Temperature (RT), 600 °C or 1000 °C. Depth profiles of implanted Xenon in UO2 are determined by Secondary Ion Mass Spectrometry (SIMS). It is shown that Xenon is mobile during irradiation at 1000 °C. In contrast, thermal treatments do not induce any Xenon migration process: these results are correlated to the formation of Xenon bubbles observed by Transmission Electron Microscopy. At depths lower than about 40 nm (zone 1), no bubbles are observed, At depths in between 40 nm and 110 nm (zone 2), a large number of small bubbles (around 2 nm in diameter) can be observed. By comparing with the SRIM profile, it appears that this area corresponds to the maximum of the defect profile, The third zone displays two bubble populations. The first population has the same size than the bubbles present in zone 2. The bubble size of the second population is significantly larger (up to around 10 nm). A STEM micrograph is presented in Fig. 4. It highlights the Xenon bubbles more clearly. It appears that the largest bubbles are located mainly near dislocations

  3. Time-resolved spectroscopic measurements behind incident and reflected shock waves in air and xenon

    NASA Technical Reports Server (NTRS)

    Yoshinaga, T.

    1973-01-01

    Time-resolved spectra have been obtained behind incident and reflected shock waves in air and xenon at initial pressures of 0.1 and 1.0 torr using a rotating drum spectrograph and the OSU (The Ohio State University) arc-driven shock tube. These spectra were used to determine the qualitative nature of the flow as well as for making estimates of the available test time. The (n+1,n) and (n,n) band spectra of N2(+) (1st negative) were observed in the test gas behind incident shock waves in air at p1=1.0 torr and Us=9-10 km/sec. Behind reflected shock waves in air, the continuum of spectra appeared to cover almost the entire wavelength of 2,500-7,000 A for the shock-heated test gas. For xenon, the spectra for the incident shock wave cases for p1=0.1 torr show an interesting structure in which two intensely bright regions are witnessed in the time direction. The spectra obtained behind reflected shock waves in xenon were also dominated by continuum radiation but included strong absorption spectra due to FeI and FeII from the moment the reflected shock passed and on.

  4. Real-time Detection of Polymerization Reactions with Hyperpolarized Xenon at Low Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Glöggler, Stefan; Blümich, Bernhard; Appelt, Stephan

    2011-03-01

    For process control it is desirable to develop simple devices for studying polymerization reactions in real-time and in-situ. We are demonstrating an approach using NMR at fields as low as 35 G and hyperpolarized xenon, which allows us to observe polymerization reactions in real-time. The investigated reaction is a free radical polymerization with the initiator azobisisobutyronitrile (AIBN) and the monomer methyl methacrylate (MMA). AIBN and MMA are mixed together in a sample tube under noble gas atmosphere, and the reaction is started by irradiation with UV light (360 nm). As the reaction goes on, xenon NMR spectra are acquired. They show increasing line broadening and a variation of the chemical shift depending on the state of polymerization. This observation gives rise to the idea that a single-sided high resolution NMR sensor can be developed with which at least light induced polymerization reactions can be studied in-situ and in real-time.

  5. PERFORMANCE OF A LIQUID XENON CALORIMETER CRYOGENIC SYSTEM FOR THE MEG EXPERIMENT

    SciTech Connect

    Haruyama, T.; Kasami, K.; Hisamitsu, Y.; Iwamoto, T.; Mihara, S.; Mori, T.; Nishiguchi, H.; Otani, W.; Sawada, R.; Uchiyama, Y.; Nishitani, T.

    2008-03-16

    The {mu}-particle rare decay physics experiment, the MU-E-GAMMA (MEG) experiment, will soon be operational at the Paul Scherrer Institute in Zurich. To achieve the extremely high sensitivity required to detect gamma rays, 800 L of liquid xenon is used as the medium in the calorimeter, viewed by 830 photomultiplier tubes (PMT) immersed in it. The required liquid xenon purity is of the order of ppb of water, and is obtained by using a cryogenic centrifugal pump and cold molecular sieves. The heat load of the calorimeter at 165 K is to be approximately 120 W, which is removed by a pulse-tube cryocooler developed at KEK and built by Iwatani Industrial Gas Corp., with a cooling power of about 200 W at 165 K. The cryogenic system is also equipped with a 1000-L dewar. This paper describes the results of an initial performance test of each cryogenic component.

  6. Xenon and halogenated alkanes track putative substrate binding cavities in the soluble methane monooxygenase hydroxylase.

    PubMed

    Whittington, D A; Rosenzweig, A C; Frederick, C A; Lippard, S J

    2001-03-27

    To investigate the role of protein cavities in facilitating movement of the substrates, methane and dioxygen, in the soluble methane monooxygenase hydroxylase (MMOH), we determined the X-ray structures of MMOH from Methylococcus capsulatus (Bath) cocrystallized with dibromomethane or iodoethane, or by using crystals pressurized with xenon gas. The halogenated alkanes bind in two cavities within the alpha-subunit that extend from one surface of the protein to the buried dinuclear iron active site. Two additional binding sites were located in the beta-subunit. Pressurization of two crystal forms of MMOH with xenon resulted in the identification of six binding sites located exclusively in the alpha-subunit. These results indicate that hydrophobic species bind preferentially in preexisting cavities in MMOH and support the hypothesis that such cavities may play a functional role in sequestering and enhancing the availability of the physiological substrates for reaction at the active site.

  7. In vivo Mapping of Local Cerebral Blood Flow by Xenon-Enhanced Computed Tomography

    NASA Astrophysics Data System (ADS)

    Gur, David; Good, Walter F.; Wolfson, Sidney K.; Yonas, Howard; Shabason, Leonard

    1982-03-01

    A noninvasive technique has been developed to measure and display local cerebral blood flow (LCBF) in vivo. In this procedure, nonradioactive xenon gas is inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computerized tomography. The time-dependent xenon concentrations in various anatomical units in the brain are used to derive both the local partition coefficient and the LCBF. Functional mapping of blood flow with excellent anatomical specificity has been obtained in the baboon brain. The response of LCBF to stimuli such as changes in carbon dioxide concentrations as well as the variability in LCBF in normal and diseased tissue can be easily demonstrated. This method is applicable to the study of human physiology and pathologic blood flow alterations.

  8. Extended-testing of xenon ion thruster hollow cathodes

    NASA Technical Reports Server (NTRS)

    Sarver-Verhey, Timothy R.

    1992-01-01

    A hollow cathode wear-test of 508 hours was successfully completed at an emission current of 23.0 A and a xenon flow rate of 10 Pa-L/s. This test was the continuation of a hollow cathode contamination investigation. Discharge voltage was stable at 16.7 V. The cathode temperature averaged 1050 C with a 7 percent drop during the wear-test. Discharge ignition voltage was found to be approximately 20 V and was repeatable over four starts. Post-test analyses of the hollow cathode found a much improved internal cathode condition with respect to earlier wear-test cathodes. Negligible tungsten movement occurred and no formation of mono-barium tungsten was observed. These results correlated with an order-of-magnitude reduction in propellant feed-system leakage rate. Ba2CaWO6 and extensive calcium crystal formation occurred on the upstream end of the insert. Ba-Ca compound depositions were found on the Mo insert collar, on the Re electrical leads, and in the gap between the insert and cathode wall. This wear-test cathode was found to be in the best internal condition and had the most stable operating performance of any hollow cathode tested during this contamination investigation.

  9. Xenon contrast CT-CBF measurements in parkinsonism and normal aging.

    PubMed

    Tachibana, H; Meyer, J S; Kitagawa, Y; Tanahashi, N; Kandula, P; Rogers, R L

    1985-06-01

    Local cerebral blood flow (LCBF) and local tissue:blood partition, coefficient (L lambda) values were measured during CT scanning while patients with different types of Parkinson's syndrome (N = 14) inhaled a contrast mixture of 35-37 per cent stable xenon gas in oxygen. Single-compartment analysis fitted to infinity was used to calculate L lambda and LCBF values. Results were compared with results from normal age-matched volunteers (N = 24). Mean hemispheric (p less than 0.05) and subcortical (p less than 0.05) gray matter LCBF values were reduced in idiopathic Parkinson's disease (N = 11), compared to values from age-matched normals. Regionally, LCBF reductions included frontal (p less than 0.001), parietal cortex (p less than 0.05), caudate (p less than 0.05), lentiform nuclei (p less than 0.001) and thalamus (p less than 0.05) reductions. L lambda values were normal. Unilateral tremor and/or rigidity correlated directly with reduced LCBF in contralateral lentiform (p less than 0.01) and caudate (p less than 0.01) nuclei. In postencephalitic Parkinsonism (N = 1) LCBF reductions were diffuse, with normal L lambda values. In the akinetic form of Parkinsonism (N = 1) associated with lacunar infarcts, LCBF and L lambda reductions were patchy. In Parkinsonism following carbon monoxide poisoning (N = 1), LCBF values of gray and white matter were diffusely reduced and L lambda values were reduced in both pallidal regions. When dementia was present together with Parkinsonism (N = 3), LCBF reductions were more diffuse and severe. Dopaminergic deficiency correlated directly with reduced LCBF values, reflecting the severity of Parkinsonism.

  10. A New Approach to the Origin of Xenon-HL

    NASA Astrophysics Data System (ADS)

    Ott, U.

    1995-09-01

    Xenon-HL carried by interstellar diamonds in primitive meteorites [1] resembles xenon produced in the p- and r-processes of nucleosynthesis (thought to occur in supernovae) in that it is enriched in the light (hence 'L'), p-only, isotopes 124,126Xe and the heavy (hence 'H'), r-only, isotopes 134,136Xe. Detailed comparison reveals different levels of enhancement in Xe-H, however, of 134Xe and 136Xe. As a result, ad-hoc scenarios have been suggested, like a mini-r-process, intermediate between s-and r-process, for producing Xe-H [2]. However, inventing a special process in order to account for a significant fraction of one element (several percent of the Xe in primitive meteorites is Xenon-HL) without evidence for such a process to have contributed significantly to anything else, is not a very attractive solution. Here we propose to consider instead that Xe-H is basically 'normal' r-process Xe that a chemical fractionation effect has turned into Xe-H. In doing so we compare r-process Xe with 'pure 'Xe-HL (i.e. Xe-HL extrapolated to 130Xe degrees 0, where 'real' HL-Xe is the product of mixing with ~ normal Xe). The r-process acts on a rapid (~1 sec) timescale (e.g. [3]), producing neutron-rich nuclides far from stability, that subsequently decay via a series of beta-decays into stable endproducts. As the precursors of the different Xe isotopes have different lifetimes, the isotopic composition of the Xe in supernova ejecta will be time-dependent on that time-scale. From the figure, where the development of the ratio 134Xe/136Xe is shown, it is obvious that after approx. 2 hours this ratio is equal to that of 'pure' Xe-H. If, at that time, a chemical separation can be achieved between the Te and I precursors on one hand and Xe on the other, we are left with Xe for which this ratio is identical to that in Xe-H. At this time little 129,131,132Xe will have been produced, because their precursors have much longer half-lives. In order to account for the small, but non

  11. Mobile high resolution xenon nuclear magnetic resonance spectroscopy in the earth's magnetic field.

    PubMed

    Appelt, Stephan; Häsing, F Wolfgang; Kühn, Holger; Perlo, Juan; Blümich, Bernhard

    2005-05-20

    Conventional high resolution nuclear magnetic resonance (NMR) spectra are usually measured in homogeneous, high magnetic fields (>1 T), which are produced by expensive and immobile superconducting magnets. We show that chemically resolved xenon (Xe) NMR spectroscopy of liquid samples can be measured in the Earth's magnetic field (5 x 10(-5) T) with a continuous flow of hyperpolarized Xe gas. It was found that the measured normalized Xe frequency shifts are significantly modified by the Xe polarization density, which causes different dipolar magnetic fields in the liquid and in the gas phases.

  12. Evaluation of hemodynamic effects of xenon in dogs undergoing hemorrhagic shock

    PubMed Central

    Franceschi, Ruben C.; Malbouisson, Luiz; Yoshinaga, Eduardo; Auler, José Otavio Costa; de Figueiredo (in memoriam), Luiz Francisco Poli; Carmona, Maria José C.

    2013-01-01

    OBJECTIVES: The anesthetic gas xenon is reported to preserve hemodynamic stability during general anesthesia. However, the effects of the gas during shock are unclear. The objective of this study was to evaluate the effect of Xe on hemodynamic stability and tissue perfusion in a canine model of hemorrhagic shock. METHOD: Twenty-six dogs, mechanically ventilated with a fraction of inspired oxygen of 21% and anesthetized with etomidate and vecuronium, were randomized into Xenon (Xe; n = 13) or Control (C; n = 13) groups. Following hemodynamic monitoring, a pressure-driven shock was induced to reach an arterial pressure of 40 mmHg. Hemodynamic data and blood samples were collected prior to bleeding, immediately after bleeding and 5, 20 and 40 minutes following shock. The Xe group was treated with 79% Xe diluted in ambient air, inhaled for 20 minutes after shock. RESULT: The mean bleeding volume was 44 mL.kg−1 in the C group and 40 mL.kg−1 in the Xe group. Hemorrhage promoted a decrease in both the cardiac index (p<0.001) and mean arterial pressure (p<0.001). These changes were associated with an increase in lactate levels and worsening of oxygen transport variables in both groups (p<0.05). Inhalation of xenon did not cause further worsening of hemodynamics or tissue perfusion markers. CONCLUSIONS: Xenon did not alter hemodynamic stability or tissue perfusion in an experimentally controlled hemorrhagic shock model. However, further studies are necessary to validate this drug in other contexts. PMID:23525321

  13. Search for WIMP inelastic scattering off xenon nuclei with XENON100

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Mora, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Xenon Collaboration

    2017-07-01

    We present the first constraints on the spin-dependent, inelastic scattering cross section of weakly interacting massive particles (WIMPs) on nucleons from XENON100 data with an exposure of 7.64 ×103 kg .days . XENON100 is a dual-phase xenon time projection chamber with 62 kg of active mass, operated at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy and designed to search for nuclear recoils from WIMP-nucleus interactions. Here we explore inelastic scattering, where a transition to a low-lying excited nuclear state of Xe 129 is induced. The experimental signature is a nuclear recoil observed together with the prompt deexcitation photon. We see no evidence for such inelastic WIMP-Xe 129 interactions. A profile likelihood analysis allows us to set a 90% C.L. upper limit on the inelastic, spin-dependent WIMP-nucleon cross section of 3.3 ×10-38 cm2 at 100 GeV /c2 . This is the most constraining result to date, and sets the pathway for an analysis of this interaction channel in upcoming, larger dual-phase xenon detectors.

  14. TSR versus non-TSR processes and their impact on gas geochemistry and carbon stable isotopes in Carboniferous, Permian and Lower Triassic marine carbonate gas reservoirs in the Eastern Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Liu, Q. Y.; Worden, R. H.; Jin, Z. J.; Liu, W. H.; Li, J.; Gao, B.; Zhang, D. W.; Hu, A. P.; Yang, C.

    2013-01-01

    The Palaeozoic and lowermost Mesozoic marine carbonate reservoirs of the Sichuan Basin in China contain variably sour and very dry gas. The source of the gas in the Carboniferous, Permian and Lower Triassic reservoirs is not known for certain and it has proved difficult to discriminate and differentiate the effects of thermal cracking- and TSR-related processes for these gases. Sixty-three gas samples were collected and analysed for their composition and carbon stable isotope values. The gases are all typically very dry (alkane gases being >97.5% methane), with low (<1%) nitrogen and highly variable H2S and CO2. Carboniferous gas is negligibly sour while the Lower Triassic gas tends to be most sour. The elevated H2S (up to 62%) is due to thermochemical sulphate reduction with the most sour Triassic and Permian reservoirs being deeper than 4800 m. The non-TSR affected Carboniferous gas is a secondary gas that was derived from the cracking of sapropelic kerogen-derived oil and primary gas and is highly mature. Carboniferous (and non-sour Triassic and Permian) gas has unusual carbon isotopes with methane and propane being isotopically heavier than ethane (a reversal of typical low- to moderate-maturity patterns). The gas in the non-sour Triassic and Permian reservoirs has the same geochemical and isotopic characteristics (and therefore the same source) as the Carboniferous gas. TSR in the deepest Triassic reservoirs altered the gas composition reaching 100% dryness in the deepest, most sour reservoirs showing that ethane and propane react faster than methane during TSR. Ethane evolves to heavier carbon isotope values than methane during TSR leading to removal of the reversed alkane gas isotope trend found in the Carboniferous and non-sour Triassic and Permian reservoirs. However, methane was directly involved in TSR as shown by the progressive increase in its carbon isotope ratio as gas souring proceeded. CO2 increased in concentration as gas souring proceeded, but

  15. Distillation purification and radon assay of liquid xenon

    SciTech Connect

    Takeuchi, Yasuo

    2005-09-08

    We succeeded to reduce the Kr contamination in liquid xenon by a factor of 1/1000 with a distillation system in Kamioka mine. Then, the remaining radioactivities (Radon and Kr) in purified liquid xenon were measured with the XMASS prototype detector. In this talk, the distillation system and the remaining internal radioactivity levels are reported.

  16. Radon concentration monitoring using xenon gamma-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Novikov, A.; Ulin, S.; Dmitrenko, V.; Chernysheva, I.; Grachev, V.; Vlasik, K.; Uteshev, Z.; Shustov, A.; Petrenko, D.; Bychkova, O.

    2017-01-01

    A method for 222Rn concentration monitoring by means of intensity measurement of its daughter nuclei (214Pb and 214Bi) gamma-ray emission using xenon gamma-ray spectrometer is presented. Testing and calibration results for a gamma-spectrometric complex based on xenon gamma-ray detector are described.

  17. Life test of a xenon hollow cathode for a space plasma contractor

    NASA Technical Reports Server (NTRS)

    Sarver-Verhey, Timothy R.

    1994-01-01

    A plasma contacting device using a hollow cathode for plasma production has been baselined for use on the Space Station. This application will require reliable, continuous operation of the cathode at electron emission currents of between 0.75 and 10 A for two years (17,500 hours). In order to validate life-time capability, a hollow cathode, operated in a diode configuration, has been tested for more than 8600 hours of stable discharge operation as of March 30, 1994. This cathode is operated at a steady-state emission current of 12.0 and a fixed xenon flow rate of 4.5 sccm. Discharge voltage and cathode temperature have remained relatively stable at approximately 12.9 V and 1260 C during the test. The test has experienced 7 shutdowns to date. In all instances, the cathode was reignited at about 42 V and resumed stable operation. This test represents the longest demonstration of stable operation of high current (greater than 1A) xenon hollow cathodes reported to date.

  18. Ionization of excited xenon atoms by electrons

    NASA Astrophysics Data System (ADS)

    Erwin, Daniel A.; Kunc, Joseph A.

    2004-08-01

    Measured cross sections for electron-impact ionization of excited Xe atoms are not presently available. Therefore, we combine in this work the formalisms of the binary encounter approximation and Sommerfeld’s quantization of atomic orbits and derive from first-principles cross sections for ionization of excited atoms by electrons of low and moderate energies (up to a few hundred eV ). The approach of this work can be used to calculate the cross sections for electron-impact ionization of excited atoms and atomic ions other than xenon.

  19. Xenon-Ion Drilling of Tungsten Films

    NASA Technical Reports Server (NTRS)

    Garner, C. E.

    1986-01-01

    High-velocity xenon ions used to drill holes of controlled size and distribution through tungsten layer that sheaths surface of controlled-porosity dispenser cathode of traveling wave-tube electron emitter. Controlled-porosity dispenser cathode employs barium/calcium/ aluminum oxide mixture that migrates through pores in cathode surface, thus coating it and reducing its work function. Rapid, precise drilling technique applied to films of other metals and used in other applications where micron-scale holes required. Method requires only few hours, as opposed to tens of hours by prior methods.

  20. Xenon-Ion Drilling of Tungsten Films

    NASA Technical Reports Server (NTRS)

    Garner, C. E.

    1986-01-01

    High-velocity xenon ions used to drill holes of controlled size and distribution through tungsten layer that sheaths surface of controlled-porosity dispenser cathode of traveling wave-tube electron emitter. Controlled-porosity dispenser cathode employs barium/calcium/ aluminum oxide mixture that migrates through pores in cathode surface, thus coating it and reducing its work function. Rapid, precise drilling technique applied to films of other metals and used in other applications where micron-scale holes required. Method requires only few hours, as opposed to tens of hours by prior methods.

  1. Xenon and other noble gases in shergottites

    NASA Technical Reports Server (NTRS)

    Swindle, T. D.; Caffee, M. W.; Hohenberg, C. M.

    1986-01-01

    The isotopic composition of the xenon component trapped in EETA 79001's lithologies B and C has been determined, and other noble gases were measured in some samples. The Xe component was found to have light isotope ratios indistinguishable from those of the terrestrial atmosphere. The trapped component has a Xe-129/Xe-132 ratio of about 2.4, and is enhanced in Xe-134 and Xe-136 relative to the terrestrial atmosphere or the average carbonaceous chondrite. Similarities between values for Ar-40/Ar-36, Xe-129/Xe-132, and N-15/N-14 and the corresponding Martian atmospheric values suggest Martian origin of the trapped gases.

  2. Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

    SciTech Connect

    Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz; Peña-Garay, C. E-mail: jmalbos@ific.uv.es E-mail: penya@ific.uv.es

    2013-03-01

    The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm{sub ν} = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m{sub ββ} involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on the double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.

  3. Doppler-free spectroscopy of xenon in the mid-infrared using difference-frequency radiation.

    PubMed

    Rusciano, G; De Luca, A; Pignatiello, F; Sasso, A

    2005-10-17

    We report on the first Doppler-free spectroscopy investigation of an atomic species, xenon, performed in the mid-infrared using difference-frequency radiation. The absorption saturated spectrum of the xenon 6p[3/2]2?5d[5/2]3 transition (2p6?3d'1 in Paschen notation) at 3.1076 microm was investigated using about 60 microwatts of cw narrowband radiation (Deltanu=50 kHz) generated by difference-frequency mixing in a periodically-poled Lithium Niobate crystal. A single frequency Ti:Sapphire laser (power 800 mW) and a monolithic diode-pumped Nd:YAG laser (300 mW) were used as pump and signal waves respectively. We used natural enriched xenon, which contains nine stable isotopes, two of which, 129Xe and 131Xe, exhibit a hyperfine structure owing to their nuclear spin. The small isotope displacements expected for this atom and the complex hyperfine structure of the odd isotopes make it difficult to fully resolve the recorded saturated-absorption spectra. In spite of this, we have been able to analyze the isolated 129Xe F''=5/2?F'=7/2 hyperfine component by means of first-derivative FM spectroscopy.

  4. Ionization efficiency studies for xenon ions with thesuperconducting ECR ion source VENUS

    SciTech Connect

    Leitner, Daniela; Lyneis, Claude M.; Todd, DamonS.; Tarvainen,Olli

    2007-06-05

    Ionization efficiency studies for high charge state xenon ions using a calibrated gas leak are presented. A 75% enriched {sup 129}Xe gas leak with a gas flow equivalent to 5.11p{mu}A was used in all the measurements. The experiments were performed at the VENUS (Versatile ECR ion source for Nuclear Science) ion source for 18 GHz, 28 GHz and double frequency operation. Overall, total ionization efficiencies close to 100% and ionization efficiencies into a single charge state up to 22% were measured. The influence of the biased disk on the ionization efficiency was studied and the results were somewhat surprising. When the biased disk was removed from the plasma chamber, the ionization efficiency was dramatically reduced for single frequency operation. However, using double frequency heating the ionization efficiencies achieved without the biased disk almost matched the ionization efficiencies achieved with the biased probe. In addition, we have studied the influence of the support gas on the charge state distribution of the xenon ions. Either pure oxygen or a mixture of oxygen and helium were used as support gases. The addition of a small amount of helium can increase the ionization efficiency into a single charge state by narrowing the charge state distribution. Furthermore by varying the helium flow the most efficient charge state can be shifted over a wide range without compromising the ionization efficiency. This is not possible using only oxygen as support gas. Results from these studies are presented and discussed.

  5. Electron drift in a large scale solid xenon

    SciTech Connect

    Yoo, J.; Jaskierny, W. F.

    2015-08-21

    A study of charge drift in a large scale optically transparent solid xenon is reported. A pulsed high power xenon light source is used to liberate electrons from a photocathode. The drift speeds of the electrons are measured using a 8.7 cm long electrode in both the liquid and solid phase of xenon. In the liquid phase (163 K), the drift speed is 0.193 ± 0.003 cm/μs while the drift speed in the solid phase (157 K) is 0.397 ± 0.006 cm/μs at 900 V/cm over 8.0 cm of uniform electric fields. Furthermore, it is demonstrated that a factor two faster electron drift speed in solid phase xenon compared to that in liquid in a large scale solid xenon.

  6. Electron drift in a large scale solid xenon

    DOE PAGES

    Yoo, J.; Jaskierny, W. F.

    2015-08-21

    A study of charge drift in a large scale optically transparent solid xenon is reported. A pulsed high power xenon light source is used to liberate electrons from a photocathode. The drift speeds of the electrons are measured using a 8.7 cm long electrode in both the liquid and solid phase of xenon. In the liquid phase (163 K), the drift speed is 0.193 ± 0.003 cm/μs while the drift speed in the solid phase (157 K) is 0.397 ± 0.006 cm/μs at 900 V/cm over 8.0 cm of uniform electric fields. Furthermore, it is demonstrated that a factor twomore » faster electron drift speed in solid phase xenon compared to that in liquid in a large scale solid xenon.« less

  7. Biophysical changes induced by xenon on phospholipid bilayers.

    PubMed

    Booker, Ryan D; Sum, Amadeu K

    2013-05-01

    Structural and dynamic changes in cell membrane properties induced by xenon, a volatile anesthetic molecule, may affect the function of membrane-mediated proteins, providing a hypothesis for the mechanism of general anesthetic action. Here, we use molecular dynamics simulation and differential scanning calorimetry to examine the biophysical and thermodynamic effects of xenon on model lipid membranes. Our results indicate that xenon atoms preferentially localize in the hydrophobic core of the lipid bilayer, inducing substantial increases in the area per lipid and bilayer thickness. Xenon depresses the membrane gel-liquid crystalline phase transition temperature, increasing membrane fluidity and lipid head group spacing, while inducing net local ordering effects in a small region of the lipid carbon tails and modulating the bilayer lateral pressure profile. Our results are consistent with a role for nonspecific, lipid bilayer-mediated mechanisms in producing xenon's general anesthetic action.

  8. Xenon isotopic composition of the Mid Ocean Ridge Basalt (MORB) source

    NASA Astrophysics Data System (ADS)

    Peto, M. K.; Mukhopadhyay, S.

    2012-12-01

    Although convection models do not preclude preservation of smaller mantle regions with more pristine composition throughout Earth's history, it has been widely assumed that the moon forming giant impact likely homogenizes the whole mantle following a magma ocean that extended all the way to the bottom of the mantle. Recent findings of tungsten and xenon heterogeneities in the mantle [1,2,3,4], however, imply that i) the moon forming giant impact may not have homogenized the whole mantle and ii) plate tectonics was inefficient in erasing early formed compositional differences, particularly for the xenon isotopes. Therefore, the xenon isotope composition in the present day mantle still preserves a memory of early Earth processes. However, determination of the xenon isotopic composition of the mantle source is still scarce, since the mantle composition is overprinted by post-eruptive atmospheric contamination in basalts erupted at ocean islands and mid ocean ridges. The xenon composition of the depleted upper mantle has been defined by the gas rich sample, 2πD43 (also known as "popping rock"), from the North Atlantic (13° 469`N). However, the composition of a single sample is not likely to define the composition of the upper mantle, especially since popping rock has an "enriched" trace element composition. We will present Ne, Ar and Xe isotope data on MORB glass samples with "normal" helium isotope composition (8±1 Ra) from the Southeast Indian Ridge, the South Atlantic Ridge, the Sojourn Ridge, the Juan de Fuca, the East Pacific Rise, and the Gakkel Ridge. Following the approach of [1], we correct for syn- and post-eruptive atmosphere contamination, and determine the variation of Ar and Xe isotope composition of the "normal" MORB source. We investigate the effect of atmospheric recycling in the variation of MORB mantle 40Ar/36Ar and 129Xe/130Xe ratios, and attempt to constrain the average upper mantle argon and xenon isotopic compositions. [1] Mukhopadhyay, Nature

  9. Toward molecular mechanism of xenon anesthesia: a link to studies of xenon complexes with small aromatic molecules.

    PubMed

    Andrijchenko, Natalya N; Ermilov, Alexander Yu; Khriachtchev, Leonid; Räsänen, Markku; Nemukhin, Alexander V

    2015-03-19

    The present study illustrates the steps toward understanding molecular mechanism of xenon anesthesia by focusing on a link to the structures and spectra of intermolecular complexes of xenon with small aromatic molecules. A primary cause of xenon anesthesia is attributed to inhibition of N-methyl-D-aspartate (NMDA) receptors by an unknown mechanism. Following the results of quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) calculations we report plausible xenon action sites in the ligand binding domain of the NMDA receptor, which are due to interaction of xenon atoms with aromatic amino-acid residues. We rely in these calculations on computational protocols adjusted in combined experimental and theoretical studies of intermolecular complexes of xenon with phenol. Successful reproduction of vibrational shifts in molecular species upon complexation with xenon measured in low-temperature matrices allowed us to select a proper functional form in density functional theory (DFT) approach for use in QM subsystems, as well as to calibrate force field parameters for MD simulations. The results of molecular modeling show that xenon atoms can compete with agonists for a place in the corresponding protein cavity, thus indicating their active role in anesthetic action.

  10. Pathway to cryogen free production of hyperpolarized Krypton-83 and Xenon-129.

    PubMed

    Six, Joseph S; Hughes-Riley, Theodore; Stupic, Karl F; Pavlovskaya, Galina E; Meersmann, Thomas

    2012-01-01

    Hyperpolarized (hp) (129)Xe and hp (83)Kr for magnetic resonance imaging (MRI) are typically obtained through spin-exchange optical pumping (SEOP) in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp (129)Xe MRI cumbersome. For hp (83)Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For (129)Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized (129)Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm(3)/min. For hp (83)Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm(3)/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D(1) transition was observed and taken into account for the qualitative description of the SEOP process.

  11. Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

    PubMed Central

    Six, Joseph S.; Hughes-Riley, Theodore; Stupic, Karl F.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2012-01-01

    Hyperpolarized (hp) 129Xe and hp 83Kr for magnetic resonance imaging (MRI) are typically obtained through spin-exchange optical pumping (SEOP) in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp 129Xe MRI cumbersome. For hp 83Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For 129Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized 129Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm3/min. For hp 83Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm3/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D1 transition was observed and taken into account for the qualitative description of the SEOP process. PMID:23209620

  12. How Stable Is Stable?

    ERIC Educational Resources Information Center

    Baehr, Marie

    1994-01-01

    Provides a problem where students are asked to find the point at which a soda can floating in some liquid changes its equilibrium between stable and unstable as the soda is removed from the can. Requires use of Newton's first law, center of mass, Archimedes' principle, stable and unstable equilibrium, and buoyant force position. (MVL)

  13. How Stable Is Stable?

    ERIC Educational Resources Information Center

    Baehr, Marie

    1994-01-01

    Provides a problem where students are asked to find the point at which a soda can floating in some liquid changes its equilibrium between stable and unstable as the soda is removed from the can. Requires use of Newton's first law, center of mass, Archimedes' principle, stable and unstable equilibrium, and buoyant force position. (MVL)

  14. Xenon ion propulsion for orbit transfer

    NASA Technical Reports Server (NTRS)

    Rawlin, V. K.; Patterson, M. J.; Gruber, R. P.

    1990-01-01

    For more than 30 years, NASA has conducted an ion propulsion program which has resulted in several experimental space flight demonstrations and the development of many supporting technologies. Technologies appropriate for geosynchronous stationkeeping, earth-orbit transfer missions, and interplanetary missions are defined and evaluated. The status of critical ion propulsion system elements is reviewed. Electron bombardment ion thrusters for primary propulsion have evolved to operate on xenon in the 5 to 10 kW power range. Thruster efficiencies of 0.7 and specific impulse values of 4000 s were documented. The baseline thruster currently under development by NASA LeRC includes ring-cusp magnetic field plasma containment and dished two-grid ion optics. Based on past experience and demonstrated simplifications, power processors for these thrusters should have approximately 500 parts, a mass of 40 kg, and an efficiency near 0.94. Thrust vector control, via individual thruster gimbals, is a mature technology. High pressure, gaseous xenon propellant storage and control schemes, using flight qualified hardware, result in propellant tankage fractions between 0.1 and 0.2. In-space and ground integration testing has demonstrated that ion propulsion systems can be successfully integrated with their host spacecraft. Ion propulsion system technologies are mature and can significantly enhance and/or enable a variety of missions in the nation's space propulsion program.

  15. Determination of stable isotopic enrichment and concentration of glycerol in plasma via gas chromatography-mass spectrometry for the estimation of lipolysis in vivo.

    PubMed

    Flakoll, P J; Zheng, M; Vaughan, S; Borel, M J

    2000-07-07

    Measuring glycerol's rate of appearance into the plasma compartment provides an excellent estimation of whole-body lipolysis. The glycerol rate of appearance can be calculated by estimating the plasma dilution of continuously infused stable or radioactive isotopes of glycerol. Previously, determination of glycerol stable isotopic enrichment has required either chemical ionization gas chromatography-mass spectrometry (GC-MS) or electron impact ionization GC-MS in which a fragment containing only a portion of the glycerol molecule was measured. The present method uses tert.-butyldimethylsilyl (tBDMS) derivatization and electron impact ionization to measure a fragment including the entire glycerol molecule. The method determines concentration and enrichment of plasma glycerol in a simple, precise, and cost-efficient manner, providing a basis from which lipid homeostasis can be assessed.

  16. Enriched xenon-124 for the production of high purity iodine-123 using a CP-42 cyclotron

    SciTech Connect

    Graham, D.; Trevena, I.C.; Webster, B.; Williams, D.

    1984-01-01

    The preferred production route for I-123 is that employing the I-127 (p,5n) reaction. This reaction requires energies beyond the capabilities of compact industrial cyclotrons. The possibility of using the reactions Xe-124 (p,2n)Cs-123 ..-->.. Xe-123..-->.. I-123, and Xe-124 (p,pn)Xe-123 ..-->.. I-123 was investigated using xenon containing 50% Xe-124. Three xenon gas targets were evaluated on an external beamline of the CP-42 cyclotron installed at TRIUMF in Vancouver. Two of these targets performed routinely with beam currents of 75..mu..A and one of these has been tested satisfactorily with natural xenon with a beam current of 150..mu..A. The targets have been relatively thin, about 1-2 MeV, with an incident proton energy of 24-26 MeV. The maximum production from a single run has been 1.1Ci I-123 at the end of chemical processing. I-125 is formed from Xe-126 present in the target gas. Because the half life of Xe-125 is 17h compared with 2h for Xe-123, the I-125 content is dependant upon the length of the irradiation and time that the target gas is allowed to decay prior to processing. With optimum timing, the I-125 content is less than 0.2% at the end of processing. I-123 is washed from the target with dilute base. Since 50% Xe-124 costs about U.S.$130/ml, processing procedures and equipment design must ensure negligible losses. This demonstration of a route for the production of I-123 will enable those with access to a compact cyclotron with an external beamline to produce ''(p,5n)'' quality I-123 using a Xe-124 gas target.

  17. A xenon ionization detector for scanned projection radiography: 95-channel prototype evaluation.

    PubMed

    Drost, D J; Fenster, A

    1984-01-01

    We have designed, constructed, and tested a 95-channel prototype xenon ionization detector for use in scanned projection radiography (SPR). This detector has higher spatial resolution, is more dose efficient, and is easier to construct than computed tomography (CT) xenon ionization detectors. It consists of two parallel plates separated by a 2-mm gap filled with xenon gas at 2 MPa (20 atm). One plate is a high-voltage electrode while the other is a circuit board etched to form an array of metal collector strips focused on the x-ray source. The resulting detector channels are 0.5 mm wide and 6 cm long. In this paper we present results from measurements of system noise and detector channel calibration. We compared the detector system to a screen/film system and found that it allows the detection of structures with 0.17% radiographic contrast compared to 2% contrast required for detection with screen/film when tested by imaging a 10-cm-thick Lucite phantom with a 10 X 10(-6) C/kg exposure. From images of resolution test patterns, the limiting resolution of the detector is 2.0 1p/mm at 1.6 magnification. Images of reduction mammoplasty tissue samples, obtained with 1/17 the exposure of screen/film images, had the same low-contrast sensitivity but contained less high-contrast detail than the film images.

  18. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression.

    PubMed

    Zheng, J; Gu, Y J; Chen, Z Y; Chen, Q F

    2010-08-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  19. Xenon for tunnelling analysis of the efflux pump component OprN

    PubMed Central

    Garnier, Cyril; Ducruix, Arnaud; Broutin, Isabelle

    2017-01-01

    Tripartite efflux pumps are among the main actors responsible for antibiotics resistance in Gram-negative bacteria. In the last two decades, structural studies gave crucial information about the assembly interfaces and the mechanistic motions. Thus rigidifying the assembly seems to be an interesting way to hamper the drug efflux. In this context, xenon is a suitable probe for checking whether small ligands could act as conformational lockers by targeting hydrophobic cavities. Here we focus on OprN, the outer membrane channel of the MexEF efflux pump from Pseudomonas aeruginosa. After exposing OprN crystals to xenon gas pressure, 14 binding sites were observed using X-ray crystallography. These binding sites were unambiguously characterized in hydrophobic cavities of OprN. The major site is observed in the sensitive iris-like region gating the channel at the periplasmic side, built by the three key-residues Leu 405, Asp 109, and Arg 412. This arrangement defines along the tunnel axis a strong hydrophobic/polar gradient able to enhance the passive efflux mechanism of OprN. The other xenon atoms reveal strategic hydrophobic regions of the channel scaffold to target, with the aim to freeze the dynamic movements responsible of the open/close conformational equilibrium in OprN. PMID:28886086

  20. Crossover Equation of State Models Applied to the Critical Behavior of Xenon

    NASA Astrophysics Data System (ADS)

    Garrabos, Y.; Lecoutre, C.; Marre, S.; Guillaument, R.; Beysens, D.; Hahn, I.

    2015-03-01

    The turbidity () measurements of Güttinger and Cannell (Phys Rev A 24:3188-3201, 1981) in the temperature range along the critical isochore of homogeneous xenon are reanalyzed. The singular behaviors of the isothermal compressibility () and the correlation length () predicted from the master crossover functions are introduced in the turbidity functional form derived by Puglielli and Ford (Phys Rev Lett 25:143-146, 1970). We show that the turbidity data are thus well represented by the Ornstein-Zernike approximant, within 1 % precision. We also introduce a new crossover master model (CMM) of the parametric equation of state for a simple fluid system with no adjustable parameter. The CMM model and the phenomenological crossover parametric model are compared with the turbidity data and the coexisting liquid-gas density difference (). The excellent agreement observed for , , , and in a finite temperature range well beyond the Ising-like preasymptotic domain confirms that the Ising-like critical crossover behavior of xenon can be described in conformity with the universal features estimated by the renormalization-group methods. Only 4 critical coordinates of the vapor-liquid critical point are needed in the (pressure, temperature, molecular volume) phase surface of xenon.

  1. Limits on GeV-scale WIMPs using charge signals in XENON100

    NASA Astrophysics Data System (ADS)

    Wall, Richard

    2014-03-01

    Various theoretical models and recent experimental results have led to growing interest in the search for WIMP-like dark matter in the mass range of a few GeV. One important class of detector used in this study is based on the liquid-gas, dual-phase Xenon time projection chamber (as in XENON100 and LUX). These detectors nominally use both scintillation (S1) and ionization (S2) signals to localize collision events in their sensitive volumes and thus reject background events, but it is known that the efficiency for detecting small S1 signals (such as are expected from a GeV-scale WIMP interaction) is much smaller than the efficiency for detecting an S2 from the same recoil. By removing the requirement of an observed S1 signal, one can thus effectively lower the energy threshold of the detector, and study GeV-scale WIMPs with greater sensitivity. With this in mind, we measure the rate of WIMP candidates in 225 live days of XENON100 data in events with small S2 signals (with or without an accompanying S1) and which pass other simple selection cuts optimized for GeV-scale WIMPs. This rate is then used to set a limit on the WIMP-nucleon cross-section for the mass range 1-10 GeV.

  2. Generalizations of the Young-Laplace equation for the pressure of a mechanically stable gas bubble in a soft elastic material

    NASA Astrophysics Data System (ADS)

    Goldman, Saul

    2009-11-01

    The Young-Laplace equation for the pressure of a mechanically stable gas bubble is generalized to include the effects of both surface tension and elastic forces of its surroundings. The latter are taken to be comprised of a soft isotropic material. Generalizations are derived for conditions of constant external pressure and constant system volume. The derived equations are formally exact for a spherical bubble surrounded by a spherical shell of isotropic material, provided that the bubble is sufficiently large for the surface tension to be treated macroscopically, and that the bubble radius is much larger than the thickness of the bubble/soft material interface. The underlying equations are also used to derive a simple expression for the Gibbs free energy of deformation of an elastic medium that surrounds a gas bubble. The possible relevance of this expression to some recently published ideas on decompression sickness ("the bends") is discussed.

  3. Formation of xenon-nitrogen compounds at high pressure

    PubMed Central

    Howie, Ross T.; Turnbull, Robin; Binns, Jack; Frost, Mungo; Dalladay-Simpson, Philip; Gregoryanz, Eugene

    2016-01-01

    Molecular nitrogen exhibits one of the strongest known interatomic bonds, while xenon possesses a closed-shell electronic structure: a direct consequence of which renders both chemically unreactive. Through a series of optical spectroscopy and x-ray diffraction experiments, we demonstrate the formation of a novel van der Waals compound formed from binary Xe-N2 mixtures at pressures as low as 5 GPa. At 300 K and 5 GPa Xe(N2)2-I is synthesised, and if further compressed, undergoes a transition to a tetragonal Xe(N2)2-II phase at 14 GPa; this phase appears to be unexpectedly stable at least up to 180 GPa even after heating to above 2000 K. Raman spectroscopy measurements indicate a distinct weakening of the intramolecular bond of the nitrogen molecule above 60 GPa, while transmission measurements in the visible and mid-infrared regime suggest the metallisation of the compound at ~100 GPa. PMID:27748357

  4. Assessing the hydraulic connection between fresh water aquifers and unconventional gas production using methane and stable isotopes

    NASA Astrophysics Data System (ADS)

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, Dave; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-04-01

    Unconventional gas developments pose a risk to groundwater quality and quantity in adjacent or overlying aquifers. To manage these risks there is a need to measure the background concentration of indicator groundwater chemicals and to map pathways of hydraulic connectivity between aquifers. This study presents methane (CH4) concentration and isotopic composition, dissolved organic carbon concentration ([DOC]) and tritium (3H) activity data from an area of expanding coal seam gas (CSG) exploration and production (Condamine Catchment, south-east Queensland, Australia). The target formation for gas production within the Condamine Catchment is the Walloon Coal Measures (WCM). This is a 700 m thick, low-rank CSG resource, which consists of numerous thin discontinuous lenses of coal separated by very fine-to medium-grained sandstone, siltstone, and mudstone, with minor calcareous sandstone, impure limestone and ironstone. The thickness of the coal makes up less than 10% of the total thickness of the unit. The WCM are overlain by sandstone formations, which form part of the Great Artesian Basin (GAB). The Condamine Alluvium fills a paleo-valley carved through the above formations. A combination of groundwater and degassing air samples were collected from irrigation bores and government groundwater monitoring boreholes. Degassing air samples were collected using an SKC 222-2301 air pump, which pumped the gas into 3 L Tedlar bags. The groundwater was analysed for 3H and [DOC]. A mobile CH4 survey was undertaken to continuously sample air in and around areas of agricultural and unconventional gas production. The isotopic signature of gas from the WCM was determined by sampling gas that was off-gassing from a co-produced water holding pond as it was the largest emission that could be directly linked to the WCM. This was used to determine the source signature of the CH4 from the WCM. We used Keeling plots to identify the source signature of the gas sampled. For the borehole

  5. Use of stable tracer studies to evaluate pesticide photolysis at elevated temperatures.

    PubMed

    Hebert, V R; Hoonhout, C; Miller, G C

    2000-05-01

    New methods were developed to determine photolysis rates of medium-weight pesticides in the gas phase using elevated air temperatures and solid-phase microextraction (SPME). A 57-L glass chamber was constructed that utilized collimated xenon arc irradiation that could heat chamber air to increase the amount of pesticide in the gas phase. Gas-phase photolysis rates were determined at various air temperatures by comparing the rate of loss of each of the tested pesticides to a photochemically stable tracer, hexachlorobenzene. Interval sampling of gas-phase constituents was performed using SPME immediately followed by GC-ECD or GC-MSD analysis. The two pesticides under examination were the dinitroaniline herbicide trifluralin and the organophosphorus insecticide chlorpyrifos. The gas-phase photolysis for trifluralin was found to be rapid with half-lives of 22-24 min corrected for sunlight. These results were comparable to photochemical lifetime estimates from other investigators under sunlight conditions. Elevating temperatures from 60 to 80 degrees C did not affect photolysis rates, and these rates could be extrapolated to environmental temperatures. From 60 to 80 degrees C, gas-phase chlorpyrifos photolysis lifetimes were observed to range from 1.4 to 2.2 h corrected for sunlight and will thus be important together with hydroxyl radical reactions for removing this substance from the atmosphere. At these elevated temperatures, pesticides and tracer compounds were found to be substantially in the gas phase, and possible effects on reaction rates from wall interactions were minimized.

  6. Xenon for NMR biosensing--inert but alert.

    PubMed

    Schröder, Leif

    2013-01-01

    NMR studies with hyperpolarized xenon as functionalized sensor or contrast agent recently made notable progress in developing a new approach for detecting molecular markers and parameters of biomedical interest. Combining spin polarization enhancement with novel indirect detection schemes easily enables a 10⁷-fold signal gain, thus having promising potential to solve the NMR sensitivity problem in many applications. Though an inert element, ¹²⁹Xe has exquisite NMR properties to sense molecular environments. This review summarizes recent developments in the production of hyperpolarized xenon and the design and detection schemes of xenon biosensors.

  7. Actinide and Xenon reactivity effects in ATW high flux systems

    SciTech Connect

    Woosley, M.; Olson, K.; Henderson, D.L.

    1995-10-01

    In this paper, initial system reactivity response to flux changes caused by the actinides and xenon are investigated separately for a high flux ATW system. The maximum change in reactivity after a flux change due to the effect of the changing quantities of actinides is generally at least two orders of magnitude smaller than either the positive or negative reactivity effect associated with xenon after a shutdown or start-up. In any transient flux event, the reactivity response of the system to xenon will generally occlude the response due to the actinides.

  8. Liquid xenon scintillators for imaging of positron emitters.

    PubMed

    Lavoie, L

    The current understanding of xenon scintillation physics is summarized and keyed to the use of xenon as a gamma-ray detector in medical radioisotope imaging systems. Liquid xenon has a short scintillation pulse (approximately 10(8) sec) and high gamma-ray absorption and scintillation efficiencies. The fast pulse may facilitate imaging in vivo distributions of hot positron sources and allow recovery of additional spatial information by time-of-flight techniques. We begin by describing our own study of the feasibility of making a practical positron scanning system, and consider the problems of scintillation decay time, linearity, efficiency, purity, and electricfield amplifcation. The prospects for a practical instrument are considered.

  9. Thermal neutrons registration by xenon gamma-ray detector

    NASA Astrophysics Data System (ADS)

    Shustov, A. E.; Chernysheva, I. V.; Dmitrenko, V. V.; Dukhvalov, A. G.; Krivova, K. V.; Novikov, A. S.; Petrenko, D. V.; Vlasik, K. F.; Ulin, S. E.; Uteshev, Z. M.

    2016-02-01

    Experimental results of thermal neutrons detection by high pressure xenon gamma- ray spectrometers are presented. The study was performed with two devices with sensitive volumes of 0.2 and 2 litters filled with compressed mixture of xenon and hydrogen without neutron-capture additives. Spectra from Pu-Be neutron source were acquired using both detectors. Count rates of the most intensive prompt neutron-capture gamma-ray lines of xenon isotopes were calculated in order to estimate thermal neutrons efficiency registration for each spectrometer.

  10. Computed tomographic measurement of the xenon brain-blood partition coefficient and implications for regional cerebral blood flow: a preliminary report.

    PubMed

    Kelcz, F; Hilal, S K; Hartwell, P; Joseph, P M

    1978-05-01

    The calculation of regional cerebral blood flow requires, in addition to the measurement of the clearance, a knowledge of the regional brain-blood partition coefficient. The usual 133Xe washout techniques do not measure this latter parameter but use published values for normal brain tissue. This may lead to large errors in pathological tissue because the partition coefficient changes significantly in brain tumors. Investigations have begun into the use of CT and stable xenon to produce a cross sectional view of the brain in terms of its brain-blood partition coefficients. Results of experiments using an iodine phantom and xenon inhalation in animals are presented.

  11. High-Performance Integrated Self-Package Flexible Li-O2 Battery Based on Stable Composite Anode and Flexible Gas Diffusion Layer.

    PubMed

    Yang, Xiao-Yang; Xu, Ji-Jing; Bao, Di; Chang, Zhi-Wen; Liu, Da-Peng; Zhang, Yu; Zhang, Xin-Bo

    2017-07-01

    With the rising development of flexible and wearable electronics, corresponding flexible energy storage devices with high energy density are required to provide a sustainable energy supply. Theoretically, rechargeable flexible Li-O2 batteries can provide high specific energy density; however, there are only a few reports on the construction of flexible Li-O2 batteries. Conventional flexible Li-O2 batteries possess a loose battery structure, which prevents flexibility and stability. The low mechanical strength of the gas diffusion layer and anode also lead to a flexible Li-O2 battery with poor mechanical properties. All these attributes limit their practical applications. Herein, the authors develop an integrated flexible Li-O2 battery based on a high-fatigue-resistance anode and a novel flexible stretchable gas diffusion layer. Owing to the synergistic effect of the stable electrocatalytic activity and hierarchical 3D interconnected network structure of the free-standing cathode, the obtained flexible Li-O2 batteries exhibit superior electrochemical performance, including a high specific capacity, an excellent rate capability, and exceptional cycle stability. Furthermore, benefitting from the above advantages, the as-fabricated flexible batteries can realize excellent mechanical and electrochemical stability. Even after a thousand cycles of the bending process, the flexible Li-O2 battery can still possess a stable open-circuit voltage, a high specific capacity, and a durable cycle performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Determination of 4-aminobutyric acid, aspartate, glutamate and glutamine and their 13C stable-isotopic enrichment in brain tissue by gas chromatography-mass spectrometry.

    PubMed

    Kapetanovic, I M; Yonekawa, W D; Kupferberg, H J

    1987-03-06

    A selected-ion monitoring method was developed for measuring 4-aminobutyric acid, aspartate, glutamate, and glutamine in brain tissue. Natural isotopes of these amino acids and their stable-isotopic enrichment following intravenous infusion of a precursor, [13C]glucose, were quantitated. Frozen mouse brain tissue was homogenized in cold 80% ethanol, and the supernatant, equivalent to 1 mg of wet weight brain tissue, was extracted using solid-phase bonded silica ion-exchange columns. Aspartate and glutamate (dicarboxylic acids) were isolated from strong anion-exchange columns, whereas 4-aminobutyric acid and glutamine (neutral amino acids) were isolated from strong-cation exchange columns. n-Butyl ester pentafluoropropionyl amide derivatives of these amino acids were analyzed by gas chromatography-mass spectrometry using a methane positive chemical ionization mode after gas chromatographic separation on a wide-bore, fused-silica capillary column. The method is applicable to determination of brain concentrations of these amino acids as well as their fluxes following administration of a stable-isotopic tracer.

  13. s-process studies - Xenon and krypton isotopic abundances

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.; Ward, R. A.

    1978-01-01

    We propose an analysis of the s-process contributions to the isotopes of xenon and krypton. The object is to aid studies of the possibility that meteorites may contain gas that was carried in presolar grains that were grown in stellar ejecta and that were not degassed prior to incorporation into parent bodies. That model suggests routine interstellar fractionation of s-isotopes from r-isotopes owing to differential incorporation into dust. We show that a deficiency of s-process nuclei cannot yield details of Xe-X, but the gross similarities are strong enough to lead one to think that such a deficiency may play a role in a more complicated explanation. We predict the existence of an s-rich complement somewhere if fractional separation of this type has played a role in Xe-X. We show that the analogous decomposition of krypton is more uncertain, and we call for measurements of neutron-capture cross sections to alleviate these uncertainties.

  14. s-process studies - Xenon and krypton isotopic abundances

    NASA Technical Reports Server (NTRS)

    Clayton, D. D.; Ward, R. A.

    1978-01-01

    We propose an analysis of the s-process contributions to the isotopes of xenon and krypton. The object is to aid studies of the possibility that meteorites may contain gas that was carried in presolar grains that were grown in stellar ejecta and that were not degassed prior to incorporation into parent bodies. That model suggests routine interstellar fractionation of s-isotopes from r-isotopes owing to differential incorporation into dust. We show that a deficiency of s-process nuclei cannot yield details of Xe-X, but the gross similarities are strong enough to lead one to think that such a deficiency may play a role in a more complicated explanation. We predict the existence of an s-rich complement somewhere if fractional separation of this type has played a role in Xe-X. We show that the analogous decomposition of krypton is more uncertain, and we call for measurements of neutron-capture cross sections to alleviate these uncertainties.

  15. Cardiac mitochondrial membrane stability after deep hypothermia using a xenon clathrate cryostasis protocol - an electron microscopy study.

    PubMed

    Sheleg, Sergey; Hixon, Hugh; Cohen, Bruce; Lowry, David; Nedzved, Mikhail

    2008-01-01

    We investigated a new cryopreservation method using xenon, a clathrate-forming gas, under medium pressure (100psi). The objective of the study was to determine whether this cryostasis protocol could protect cardiac mitochondria at cryogenic temperatures (below 100 degrees Celsius).We analyzed transmission electron microscopy images to obtain information about changes in mitochondrial morphology induced by cryopreservation of the hearts. Our data showed absence of mitochondrial swelling, rupture of inner and outer membranes, and leakage of mitochondrial matrix into the cytoplasm after applying this cryostasis protocol. The electron microscopy results provided the first evidence that a cryostasis protocol using xenon as a clathrate-forming gas under pressure may have protective effects on intracellular membranes. This cryostasis technology may find applications in developing new approaches for long-term cryopreservation protocols.

  16. Cardiac Mitochondria l Membrane Stability after Deep Hypothermia using a Xenon Clathrate Cryostasis Protocol – an Electron Microscopy Study

    PubMed Central

    Sheleg, Sergey; Hixon, Hugh; Cohen, Bruce; Lowry, David; Nedzved, Mikhail

    2008-01-01

    We investigated a new cryopreservation method using xenon, a clathrate-forming gas, under medium pressure (100psi). The objective of the study was to determine whether this cryostasis protocol could protect cardiac mitochondria at cryogenic temperatures (below 100 degrees Celsius).We analyzed transmission electron microscopy images to obtain information about changes in mitochondrial morphology induced by cryopreservation of the hearts. Our data showed absence of mitochondrial swelling, rupture of inner and outer membranes, and leakage of mitochondrial matrix into the cytoplasm after applying this cryostasis protocol. The electron microscopy results provided the first evidence that a cryostasis protocol using xenon as a clathrate-forming gas under pressure may have protective effects on intracellular membranes. This cryostasis technology may find applications in developing new approaches for long-term cryopreservation protocols. PMID:18787624

  17. Design and Performance Assessment of a Stable Astigmatic Herriott Cell for Trace Gas Measurements on Airborne Platforms

    NASA Technical Reports Server (NTRS)

    Dyroff, Christoph; Fried, Alan; Richter, Dirk; Walega, James G.; Zahniser, Mark S.; McManus, J. Barry

    2005-01-01

    The present paper discusses a new, more stable, astigmatic Herriott cell employing carbon fiber stabilizing rods. Laboratory tests using a near-IR absorption feature of CO at 1564.168-nm revealed a factor of two improvement in measurement stability compared with the present commercial design when the sampling pressure was changed by +/-2 Torr around 50 Torr. This new cell should significantly enhance our efforts to measure trace gases employing pathlengths of 100 to 200-meters on airborne platforms with minimum detectable line center absorbances of less than 10(exp -6).

  18. Viscoelasticity of Xenon near the Critical Point

    NASA Technical Reports Server (NTRS)

    Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.

    1999-01-01

    Using a novel, overdamped, oscillator flown aboard the Space Shuttle, we measured the viscosity of xenon near the liquid-vapor critical point in the frequency range 2 Hz less than or equal to f less than or equal to 12 Hz. The measured viscosity divergence is characterized by the exponent z(sub eta) = 0.0690 +/- 0.0006, in agreement with the value z(sub eta) = 0.067 +/- 0.002 calculated from a two-loop perturbation expansion. Viscoelastic behavior was evident when t = (T - T(sub c))/T(sub c) less than 10(exp -5) and dominant when t less than 10(exp -6), further from T(sub c) than predicted. Viscoelastic behavior scales as Af(tau) where tau is the fluctuation decay time. The measured value of A is 2.0 +/- 0.3 times the result of a one-loop calculation. (Uncertainties stated are one standard uncertainty.)

  19. Viscosity of Xenon Examined in Microgravity

    NASA Technical Reports Server (NTRS)

    Zimmerli, Gregory A.; Berg, Robert F.; Moldover, Michael R.

    1999-01-01

    Why does water flow faster than honey? The short answer, that honey has a greater viscosity, merely rephrases the question. The fundamental answer is that viscosity originates in the interactions between a fluid s molecules. These interactions are so complicated that, except for low-density gases, the viscosity of a fluid cannot be accurately predicted. Progress in understanding viscosity has been made by studying moderately dense gases and, more recently, fluids near the critical point. Modern theories predict a universal behavior for all pure fluids near the liquid-vapor critical point, and they relate the increase in viscosity to spontaneous fluctuations in density near this point. The Critical Viscosity of Xenon (CVX) experiment tested these theories with unprecedented precision when it flew aboard the Space Shuttle Discovery (STS-85) in August 1997. Near the critical point, xenon is a billion times more compressible than water, yet it has about the same density. Because the fluid is so "soft," it collapses under its own weight when exposed to the force of Earth s gravity - much like a very soft spring. Because the CVX experiment is conducted in microgravity, it achieves a very uniform fluid density even very close to the critical point. At the heart of the CVX experiment is a novel viscometer built around a small nickel screen. An oscillating electric field forces the screen to oscillate between pairs of electrodes. Viscosity, which dampens the oscillations, can be calculated by measuring the screen motion and the force applied to the screen. So that the fluid s delicate state near the critical point will not be disrupted, the screen oscillations are set to be both slow and small.

  20. Important considerations in the use of carbon and hydrogen stable isotopes to determine the origin of hydrocarbons in groundwater – A case study from pre-shale gas Tioga County

    EPA Pesticide Factsheets

    stable carbon and hydrogen isotopic compositional ranges of methanes (δ13C and δ2H (D)) enable us to distinguish between microbial and thermogenic origin of natural gases. To identify stray gas origins, identify possible gas sources, create baseline, carry out site-specific monitoring, and monitor long-term changes

  1. Effect of xenon on the excited states of phototropic receptor flavin in corn seedlings

    SciTech Connect

    Vierstra, R.D.; Poff, K.L.; Walker, E.B.; Song, P.S.

    1981-05-01

    The chemically inert, water-soluble heavy atom gas, xenon, at millimolar concentrations specifically quenches the triplet excited state of flavin in solution without quenching the flavin singlet excited state. The preferential quenching of the flavin triplet over the singlet excited state by Xe has been established by showing that the flavin triplet-sensitized photooxidation of NADH is inhibited while the fluorescence intensity and lifetime of flavin are not affected by Xe. No significant inhibition of phototropism and geotropism by Xe was observed, suggesting that a flavin singlet state is more likely involved than the triplet state in the primary photoprocess of phototropism in corn.

  2. Influence of humidity on photochemical ozone generation with 172nm xenon excimer lamps

    NASA Astrophysics Data System (ADS)

    Salvermoser, M. J.; Kogelschatz, U.; Murnick, D. E.

    2009-08-01

    The reaction kinetics of photochemical ozone (O{3}) generation in humid air and oxygen (O{2}) using efficient, narrow band vacuum ultra violet (VUV) 172 nm xenon excimer lamps is discussed. Trace amounts of water (H{2}O) vapor in the process gas leads to hydroxyl (OH) and hydroperoxy (HO{2}) radical formation. These radicals drive a catalytic O{3} destruction cycle limiting O{3} saturation concentration. This catalytic O{3} destruction cycle was included into a quantitative kinetic model describing photochemical O{3} production. Experimental O{3} saturation concentrations obtained with coaxial VUV driven photochemical O{3} generators compare satisfactorily with the models predictions.

  3. 2 dimensional electron gas in chemically stable SrSnO3/KTaO3 interface

    NASA Astrophysics Data System (ADS)

    Kwon, Hyukwoo; Park, Chulkwon; Char, Kookrin; Materials and Devices Physics Lab. Team

    2013-03-01

    Recent 2DEGs are mostly formed at the interface of LaAlO3/SrTiO3(LAO/STO) system, which is explained by the polar catastrophe mechanism. Because of large propensity of oxygen vacancy formation in SrTiO3, there remains a possibility that the origin of 2DEG of LAO/STO system may stem from extra charge of oxygen vacancy of SrTiO3, not from the polar layer of LaAlO3. In this presentation, we report the realization of 2DEG at the interface of SrSnO3/KTaO3(SSO/KTO), which is chemically stable due to extremely stable oxygen stoichiometry. This SrSnO3/KTaO3 heterosturcture was epitaxially grown by puled laser deposition and the interface was found atomically matched by transmission electron microscope and reciprocal space mapping. We measured the magnetic property of SSO/KTO heterostructure and acquired a large ferromagnetic signal, which is unchanged in the temperature range of 4 ~300 K by SQUID magnetometer measurement. As SrSnO3 and KTaO3 are non-magnetic materials, this ferromagnetic signal may result from 2DEG at the interface of SSO/KTO. We hope our results can shed lights on the exact mechanism of 2DEGs that are formed at oxide interfaces.

  4. First demonstration of VUV-photon detection in liquid xenon with THGEM and GEM-based Liquid Hole Multipliers

    NASA Astrophysics Data System (ADS)

    Erdal, E.; Arazi, L.; Rappaport, M. L.; Shchemelinin, S.; Vartsky, D.; Breskin, A.

    2017-02-01

    The bubble-assisted Liquid Hole-Multiplier (LHM) is a recently-introduced detection concept for noble-liquid time projection chambers. In this ;local dual-phase; detection element, a gas bubble is supported underneath a perforated electrode (e.g., Thick Gas Electron Multiplier - THGEM, or Gas Electron Multiplier - GEM). Electrons drifting through the holes induce large electroluminescence signals as they pass into the bubble. In this work we report on recent results of THGEM and GEM electrodes coated with cesium iodide and immersed in liquid xenon, allowing - for the first time - the detection of primary VUV scintillation photons in addition to ionization electrons.

  5. Stark Widths Of Ionized Xenon UV Lines Of Low Intensity

    SciTech Connect

    Cirisan, M.; Djurovic, S.; Pelaez, R. J.; Aparicio, J. A.; Mar, S.

    2007-04-23

    Stark width measurements of several low intensity Xe II spectral lines (5d - 4f transitions) in UV region, are presented here for the first time. These measurements were obtained from helium - xenon pulsed arc plasma.

  6. Fission xenon from extinct Pu-244 in 14,301.

    NASA Technical Reports Server (NTRS)

    Drozd, R.; Hohenberg, C. M.; Ragan, D.

    1972-01-01

    Xenon extracted in step-wise heating of lunar breccia 14,301 contains a fission-like component in excess of that attributable to uranium decay during the age of the solar system. There seems to be no adequate source for this component other than Pu-244. Verification that this component is in fact due to the spontaneous fission of extinct Pu-244 comes from the derived spectrum which is similar to that observed from artificially produced Pu-244. It thus appears that Pu-244 was extant at the time lunar crustal material cooled sufficiently to arrest the thermal diffusion of xenon. Subsequent history has apparently maintained the isotopic integrity of plutonium fission xenon. Of major importance are details of the storage itself. Either the fission component is the result of in situ fission of Pu-244 and subsequent storage in 14,301 material, or the fission xenon was stored in an intermediate reservoir before incorporation into 14,301.

  7. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, R.B.

    1987-05-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  8. Fluorination of amorphous thin-film materials with xenon fluoride

    DOEpatents

    Weil, Raoul B.

    1988-01-01

    A method is disclosed for producing fluorine-containing amorphous semiconductor material, preferably comprising amorphous silicon. The method includes depositing amorphous thin-film material onto a substrate while introducing xenon fluoride during the film deposition process.

  9. The unbearable lightness of being: CDMS versus XENON

    SciTech Connect

    Frandsen, Mads T.; Kahlhoefer, Felix; Sarkar, Subir; McCabe, Christopher; Schmidt-Hoberg, Kai E-mail: felix.kahlhoefer@physics.ox.ac.uk E-mail: s.sarkar@physics.ox.ac.uk

    2013-07-01

    The CDMS-II collaboration has reported 3 events in a Si detector, which are consistent with being nuclear recoils due to scattering of Galactic dark matter particles with a mass of ∼ 8.6 GeV and a cross-section on neutrons of ∼ 2 × 10{sup −41} cm{sup 2}. While a previous result from the XENON10 experiment has supposedly ruled out such particles as dark matter, we find by reanalysing the XENON10 data that this is not the case. Some tension remains however with the upper limit placed by the XENON100 experiment, independently of astrophysical uncertainties concerning the Galactic dark matter distribution. We explore possible ways of ameliorating this tension by altering the properties of dark matter interactions. Nevertheless, even with standard couplings, light dark matter is consistent with both CDMS and XENON10/100.

  10. Gas

    MedlinePlus

    ... intestine. Certain foods may cause gas. Foods that produce gas in one person may not cause gas in another. You can reduce the amount of gas you have by Drinking lots of water and non-fizzy drinks Eating more slowly so you swallow less air ...

  11. Using noble-gas and stable-isotope data to determine groundwater origin and flow regimes: Application to the Ceneri Base Tunnel (Switzerland)

    NASA Astrophysics Data System (ADS)

    Tomonaga, Yama; Marzocchi, Roberto; Pera, Sebastian; Pfeifer, Hans-Rudolf; Kipfer, Rolf; Decrouy, Laurent; Vennemann, Torsten

    2017-02-01

    Tunnel drilling provides a unique opportunity to sample and study deep groundwaters that are otherwise difficult to access. Understanding deep groundwater flow is of primary importance in assessing the possible impacts of tunnelling on hydrogeological systems. During this study, water was sampled for noble-gas analysis from tunnel inflows in the AlpTransit Ceneri Base Tunnel (Canton Ticino, southern Switzerland), which passes through an area mainly characterized by metamorphic rocks (gneiss). Furthermore, water was sampled from springs located in the same geological environment. Based on the measurement of noble-gas concentrations and isotope ratios, tritium concentrations, the stable isotope composition of hydrogen (δ2H) and oxygen (δ18O), and the concentrations of major ions in the water, a conceptual hydrogeological model was established for this case study that allowed the most probable origin of the groundwaters sampled at different locations to be determined. The measured abundances of 3He, 4He, and 20Ne allow the geochemical characterization of old groundwaters strongly enriched in terrigenic helium of crustal origin and the identification of mixing with water that circulates preferentially through cataclastic structures. Noble-gas concentrations and isotope ratios as well as tritium are useful proxies for the characterization of faults that may be critical for tunnel drilling because of their active hydrogeological role and their influence on the mechanics of the rocks.

  12. High-temperature pyrolysis/gas chromatography/isotope ratio mass spectrometry: simultaneous measurement of the stable isotopes of oxygen and carbon in cellulose.

    PubMed

    Woodley, Ewan J; Loader, Neil J; McCarroll, Danny; Young, Giles H F; Robertson, Iain; Heaton, Timothy H E; Gagen, Mary H; Warham, Joseph O

    2012-01-30

    Stable isotope analysis of cellulose is an increasingly important aspect of ecological and palaeoenvironmental research. Since these techniques are very costly, any methodological development which can provide simultaneous measurement of stable carbon and oxygen isotope ratios in cellulose deserves further exploration. A large number (3074) of tree-ring α-cellulose samples are used to compare the stable carbon isotope ratios (δ(13)C) produced by high-temperature (1400°C) pyrolysis/gas chromatography (GC)/isotope ratio mass spectrometry (IRMS) with those produced by combustion GC/IRMS. Although the two data sets are very strongly correlated, the pyrolysis results display reduced variance and are strongly biased towards the mean. The low carbon isotope ratios of tree-ring cellulose during the last century, reflecting anthropogenic disturbance of atmospheric carbon dioxide, are thus overestimated. The likely explanation is that a proportion of the oxygen atoms are bonding with residual carbon in the reaction chamber to form carbon monoxide. The 'pyrolysis adjustment', proposed here, is based on combusting a stratified sub-sample of the pyrolysis results, across the full range of carbon isotope ratios, and using the paired results to define a regression equation that can be used to adjust all the pyrolysis measurements. In this study, subsamples of 30 combustion measurements produced adjusted chronologies statistically indistinguishable from those produced by combusting every sample. This methodology allows simultaneous measurement of the stable isotopes of carbon and oxygen using high-temperature pyrolysis, reducing the amount of sample required and the analytical costs of measuring them separately.

  13. A comparative study of TiN and TiC: Oxidation resistance and retention of xenon at high temperature and under degraded vacuum

    NASA Astrophysics Data System (ADS)

    Gavarini, S.; Bes, R.; Millard-Pinard, N.; Cardinal, S.; Peaucelle, C.; Perrat-Mabilon, A.; Garnier, V.; Gaillard, C.

    2011-01-01

    Dense TiN and TiC samples were prepared by hot pressing using micrometric powders. Xenon species (simulating rare gas fission products) were then implanted into the ceramics. The samples were annealed for 1 h at 1500 °C under several degraded vacuums with PO2 varying from 10-6 to 2×10-4 mbars. The oxidation resistance of the samples and their retention properties with respect to preimplanted xenon species were analyzed using scanning electron microscopy, grazing incidence x-ray diffraction, Rutherford backscattering spectrometry, and nuclear backscattering spectrometry. Results indicate that TiC is resistant to oxidation and does not release xenon for PO2≤6×10-6 mbars. When PO2 increases, geometric oxide crystallites appear at the surface depending on the orientation and size of TiC grains. These oxide phases are Ti2O3, Ti3O5, and TiO2. Apparition of oxide crystallites is associated with the beginning of xenon release. TiC surface is completely covered by the oxide phases at PO2=2×10-4 mbars up to a depth of 3 μm and the xenon is then completely released. For TiN samples, the results show a progressive apparition of oxide crystallites (Ti3O5 mainly) at the surface when PO2 increases. The presence of the oxide crystallites is also directly correlated with xenon release, the more oxide crystallites are growing the more xenon is released. TiN surface is completely covered by an oxide layer at PO2=2×10-4 mbars up to 1 μm. A correlation between the initial fine microstructure of TiN and the properties of the growing layer is suggested.

  14. Odorant Screening and Quantitation of Thiols in Carmenere Red Wine by Gas Chromatography-Olfactometry and Stable Isotope Dilution Assays.

    PubMed

    Pavez, Carolina; Agosin, Eduardo; Steinhaus, Martin

    2016-05-04

    The sensory impact of thiols in Vitis vinifera 'Carmenere' red wines was evaluated. For this purpose, aroma extract dilution analysis was applied to the thiols isolated from a Carmenere red wine by affinity chromatography with a mercurated agarose gel. Results revealed the presence of four odorants, identified as 2-furanylmethanethiol, 3-sulfanylhexyl acetate, 3-sulfanyl-1-hexanol, and 2-methyl-3-sulfanyl-1-butanol, with the latter being described here for the first time in Carmenere red wines. Quantitation of the four thiols in the Carmenere wine screened by aroma extract dilution analysis and in three additional Carmenere wines by stable isotope dilution assays resulted in concentrations above the respective orthonasal odor detection threshold values. Triangle tests applied to wine model solutions with and without the addition of the four thiols showed significant differences, thus suggesting that the compounds do have the potential to influence the overall aroma of red wine.

  15. Post-irradiation analysis of an ISOLDE lead-bismuth target: Stable and long-lived noble gas nuclides

    NASA Astrophysics Data System (ADS)

    Leya, I.; Grimberg, A.; David, J.-C.; Schumann, D.; Neuhausen, J.; Zanini, L.; Noah, E.

    2016-07-01

    We measured the isotopic concentrations of long-lived and stable He, Ne, Ar, Kr, and Xe isotopes in a sample from a lead-bismuth eutectic target irradiated with 1.0 and 1.4 GeV protons. Our data indicate for most noble gases nearly complete release with retention fractions in the range of percent or less. Higher retention fractions result from the decay of long-lived radioactive progenitors from groups 1, 2, or 7 of the periodic table. From the data we can calculate a retention fraction for 3H of 2-3%. For alkaline metals we find retention fractions of about 10%, 30%, and 50% for Na, Rb, and Cs, respectively. For the alkaline earth metal Ba we found complete retention. Finally, the measured Kr and Xe concentrations indicate that there was some release of the halogens Br and I during and/or after the irradiation.

  16. Capturing Polyradical Protein Cations after an Electron Capture Event: Evidence for their Stable Distonic Structures in the Gas Phase

    NASA Astrophysics Data System (ADS)

    Baba, Takashi; Campbell, J. Larry

    2015-08-01

    We report on the formation and "capture" of polyradical protein cations after an electron capture event. Performed in a unique electron-capture dissociation (ECD) instrument, these experiments can generate reduced forms of multiply protonated proteins by sequential charge reduction using electrons with ~1 eV. The true structures of these possible polyradicals is considered: Do the introduced unpaired electrons recombine quickly to form a new two-electron bond, or do these unpaired electrons exist as radical sites with appropriate chemical reactivity? Using an established chemical probe—radical quenching with molecular oxygen—we demonstrate that these charge-reduced protein cations are indeed polyradicals that form adducts with up to three molecules of oxygen (i.e., tri-radical protein cations) that are stable for at least 100 ms.

  17. Using game theory approach to interpret stable policies for Iran's oil and gas common resources conflicts with Iraq and Qatar

    NASA Astrophysics Data System (ADS)

    Esmaeili, Maryam; Bahrini, Aram; Shayanrad, Sepideh

    2015-08-01

    Oil and gas as the non-renewable resources are considered very valuable for the countries with petroleum economics. These resources are not only diffused equally around the world, but also they are common in some places which their neighbors often come into conflicts. Consequently, it is vital for those countries to manage their resource utilization. Lately, game theory was applied in conflict resolution of common resources, such as water, which is a proof of its efficacy and capability. This paper models the conflicts between Iran and its neighbors namely Qatar and Iraq between their oil and gas common resources using game theory approach. In other words, the future of these countries will be introduced and analyzed by some well-known 2 × 2 games to achieve a better perspective of their conflicts. Because of information inadequacy of the players, in addition to Nash Stability, various solution concepts are used based on the foresight, disimprovements, and knowledge of preferences. The results of mathematical models show how the countries could take a reasonable strategy to exploit their common resources.

  18. Factors affecting the adsorption of xenon on activated carbon

    SciTech Connect

    Underhill, D.W.; DiCello, D.C.; Scaglia, L.A.; Watson, J.A.

    1986-08-01

    The presence of water vapor was found to interfere strongly with the dynamic adsorption of /sup 133/Xe on coconut-base activated charcoal. The percent loss in the xenon adsorption coefficient was similar to values reported earlier for the adsorption of krypton on humidified charcoal. Attempts to increase the adsorption of xenon by (a) using a petroleum-based adsorbent with an extremely high surface area and (b) by impregnation of the adsorbent with iodine were not successful.

  19. Software tool for xenon gamma-ray spectrometer control

    NASA Astrophysics Data System (ADS)

    Chernysheva, I. V.; Novikov, A. S.; Shustov, A. E.; Dmitrenko, V. V.; Pyae Nyein, Sone; Petrenko, D.; Ulin, S. E.; Uteshev, Z. M.; Vlasik, K. F.

    2016-02-01

    Software tool "Acquisition and processing of gamma-ray spectra" for xenon gamma-ray spectrometers control was developed. It supports the multi-windows interface. Software tool has the possibilities for acquisition of gamma-ray spectra from xenon gamma-ray detector via USB or RS-485 interfaces, directly or via TCP-IP protocol, energy calibration of gamma-ray spectra, saving gamma-ray spectra on a disk.

  20. Charge-Transfer Interactions between Transition Metal Hexafluorides and Xenon

    DTIC Science & Technology

    1977-10-01

    HEXAFLUORIDES AND XENON’. by J. D./Webb M E. R./Bernstein\\ Prepared for Publication in the Journal of the American Chemical Society DTIE Department of...Metal Hexafluorides ar. Xenon" " 6. PERFORMIKG ORG REPk)RT NUMODE . CONTRACT OR GNANT NUMBLR(e) J. D. Webb and E. R. Bernstein N00014-75-C-1179 9...neceoswy and Idenifil by block numbet) charge transfer electron affinities Transitio Metal Hexafluorides Xencn electronegativities 4,AGSTRACT Coninue an

  1. Xenon for the prevention of postoperative delirium in cardiac surgery: study protocol for a randomized controlled clinical trial.

    PubMed

    Al Tmimi, Layth; Van de Velde, Marc; Herijgers, Paul; Meyns, Bart; Meyfroidt, Geert; Milisen, Koen; Fieuws, Steffen; Coburn, Mark; Poesen, Koen; Rex, Steffen

    2015-10-09

    Postoperative delirium (POD) is a manifestation of acute postoperative brain dysfunction that is frequently observed after cardiac surgery. POD is associated with short-term complications such as an increase in mortality, morbidity, costs and length of stay, but can also have long-term sequelae, including persistent cognitive deficits, loss of independence, and increased mortality for up to 2 years. The noble gas xenon has been demonstrated in various models of neuronal injury to exhibit remarkable neuroprotective properties. We therefore hypothesize that xenon anesthesia reduces the incidence of POD in elderly patients undergoing cardiac surgery with the use of cardiopulmonary bypass. One hundred and ninety patients, older than 65 years, and scheduled for elective cardiac surgery, will be enrolled in this prospective, randomized, controlled trial. Patients will be randomized to receive general anesthesia with either xenon or sevoflurane. Primary outcome parameter will be the incidence of POD in the first 5 postoperative days. The occurrence of POD will be assessed by trained research personnel, blinded to study group, with the validated 3-minute Diagnostic Confusion Assessment Method (3D-CAM) (on the intensive care unit in its version specifically adapted for the ICU), in addition to chart review and the results of delirium screening tools that will be performed by the bedside nurses). Secondary outcome parameters include duration and severity of POD, and postoperative cognitive function as assessed with the Mini-Mental State Examination. Older patients undergoing cardiac surgery are at particular risk to develop POD. Xenon provides remarkable hemodynamic stability and has been suggested in preclinical studies to exhibit neuroprotective properties. The present trial will assess whether the promising profile of xenon can be translated into a better outcome in the geriatric population. EudraCT Identifier: 2014-005370-11 (13 May 2015).

  2. On-line stable isotope gas exchange reveals an inducible but leaky carbon concentrating mechanism in Nannochloropsis salina.

    PubMed

    Hanson, David T; Collins, Aaron M; Jones, Howland D T; Roesgen, John; Lopez-Nieves, Samuel; Timlin, Jerilyn A

    2014-09-01

    Carbon concentrating mechanisms (CCMs) are common among microalgae, but their regulation and even existence in some of the most promising biofuel production strains is poorly understood. This is partly because screening for new strains does not commonly include assessment of CCM function or regulation despite its fundamental role in primary carbon metabolism. In addition, the inducible nature of many microalgal CCMs means that environmental conditions should be considered when assessing CCM function and its potential impact on biofuels. In this study, we address the effect of environmental conditions by combining novel, high frequency, on-line (13)CO2 gas exchange screen with microscope-based lipid characterization to assess CCM function in Nannochloropsis salina and its interaction with lipid production. Regulation of CCM function was explored by changing the concentration of CO2 provided to continuous cultures in airlift bioreactors where cell density was kept constant across conditions by controlling the rate of media supply. Our isotopic gas exchange results were consistent with N. salina having an inducible "pump-leak" style CCM similar to that of Nannochloropsis gaditana. Though cells grew faster at high CO2 and had higher rates of net CO2 uptake, we did not observe significant differences in lipid content between conditions. Since the rate of CO2 supply was much higher for the high CO2 conditions, we calculated that growing cells bubbled with low CO2 is about 40 % more efficient for carbon capture than bubbling with high CO2. We attribute this higher efficiency to the activity of a CCM under low CO2 conditions.

  3. Investigations of Buffer-Gases Role in Xenon and Halogen Excimer Mixtures

    NASA Astrophysics Data System (ADS)

    Ciobotaru, L. C.; Porosnicu, C.

    2010-10-01

    Excimer- is an acronym in use for the excited dimmer, molecule which does not exist in the ground state but only in an excited state. This paper presents the role of the buffer-gas atoms (Ar, Ne, He), in the (Cl2/I2 Xe) excimer radiation emission mechanisms. The same buffer-gas produced a different effect on the excimer emission intensity: the neon and argon addition to xenon/chlorine/iodine had a negative effect while the helium and neon addition had a positive effect. The Penning reactions play an important role in the excimer radiation generation in connection with the gas-buffer addition and the halogen ionization potential value. The measurements are performed using a dielectric barrier discharge (DBD) at moderate pressure in a panel, respectively classic coaxial geometry.

  4. 17 alpha-hydroxyprogesterone, 4-androstenedione, and testosterone profiled by routine stable isotope dilution/gas chromatography-mass spectrometry in plasma of children.

    PubMed

    Wudy, S A; Wachter, U A; Homoki, J; Teller, W M

    1995-07-01

    Using stable isotope dilution/gas chromatography-mass spectrometry (ID/GC-MS), a physicochemical method, we have profiled the plasma steroids 17 alpha-hydroxyprogesterone, 4-androstenedione, and testosterone in normal children of various age groups. Comparison of our values with those obtained by direct immunologic assays and those using an extraction or purification step showed that immunoassays in general overestimate steroid concentrations. This was especially true for plasma samples in the neonatal period and was most expressed for the concentrations of 17 alpha-hydroxyprogesterone. Our study demonstrated the applicability of ID/GC-MS to routine clinical steroid analysis. The application of ID/GC-MS is recommended whenever problems from matrix effects or cross-reactivity are likely to arise or suspicious results by immunoassays need to be rechecked.

  5. Influence of xenon on the self-reversal maxima of the Na-D emission lines in high-pressure sodium lamps

    NASA Astrophysics Data System (ADS)

    Jongerius, M. J.

    1987-10-01

    We report on the influence of xenon buffer gas on the shape of the self-reversed Na-D lines emitted by high-pressure sodium (HPS) arcs. In a previous paper we have reported experimental results on the collisional broadening of the Na-D line wings by xenon at high temperatures [M. J. Jongerius, J. Phys. B 20, 3345 (1987)]. These results are used to calculate the relative wavelength positions Δλr and Δλb of the red and blue Na-D self-reversal maximum, respectively, as functions of the Na/Hg amalgam temperature. The additional broadening by xenon leads to a strong asymmetry in the shape of the Na-D emission lines and a distinct maximum in Δλr/Δλb because of the Na-Xe satellite at 590.9 nm. The presence of this maximum in Δλr/Δλb is confirmed by experiments in which the shape of the Na-D emission lines is measured as a function of the arc power. The maximum value of Δλr/Δλb can be used as a measure of the xenon pressure in the arc. Furthermore, Δλr and Δλb can be used to obtain values for the sodium and mercury pressures in the burning arc. In the conventional method (J. J. de Groot and J. A. J. M. van Vliet, in Proceedings of the 2nd International Symposium on Incoherent Light Sources, Enschede, 1979, summary p. 30), the Na-D line broadening by the xenon buffer gas is not taken into account. We propose a modification of the conventional method to account for the influence of the collisional Na-D line broadening by xenon.

  6. LabData database sub-systems for post-processing and quality control of stable isotope and gas chromatography measurements

    NASA Astrophysics Data System (ADS)

    Suckow, A. O.

    2013-12-01

    Measurements need post-processing to obtain results that are comparable between laboratories. Raw data may need to be corrected for blank, memory, drift (change of reference values with time), linearity (dependence of reference on signal height) and normalized to international reference materials. Post-processing parameters need to be stored for traceability of results. State of the art stable isotope correction schemes are available based on MS Excel (Geldern and Barth, 2012; Gröning, 2011) or MS Access (Coplen, 1998). These are specialized to stable isotope measurements only, often only to the post-processing of a special run. Embedding of algorithms into a multipurpose database system was missing. This is necessary to combine results of different tracers (3H, 3He, 2H, 18O, CFCs, SF6...) or geochronological tools (Sediment dating e.g. with 210Pb, 137Cs), to relate to attribute data (submitter, batch, project, geographical origin, depth in core, well information etc.) and for further interpretation tools (e.g. lumped parameter modelling). Database sub-systems to the LabData laboratory management system (Suckow and Dumke, 2001) are presented for stable isotopes and for gas chromatographic CFC and SF6 measurements. The sub-system for stable isotopes allows the following post-processing: 1. automated import from measurement software (Isodat, Picarro, LGR), 2. correction for sample-to sample memory, linearity, drift, and renormalization of the raw data. The sub-system for gas chromatography covers: 1. storage of all raw data 2. storage of peak integration parameters 3. correction for blank, efficiency and linearity The user interface allows interactive and graphical control of the post-processing and all corrections by export to and plot in MS Excel and is a valuable tool for quality control. The sub-databases are integrated into LabData, a multi-user client server architecture using MS SQL server as back-end and an MS Access front-end and installed in four

  7. Gas and particle concentrations in horse stables with individual boxes as a function of the bedding material and the mucking regimen.

    PubMed

    Fleming, K; Hessel, E F; Van den Weghe, H F A

    2009-11-01

    The aim of this study was to compare different types of bedding and mucking regimens used in horse stables on the generation of airborne particulate matter <10 microm (PM10) and 3 biogenic gases (carbon dioxide, nitrous oxide, and especially ammonia). Three separate experiments were undertaken. The experiments were carried out in an enclosed stable (9.7 m long, 8.7 m wide, and 3.5 m high) that had 5 single boxes housing 4 horses. The measuring instruments were set up in the middle of one side of the stable. In Exp. 1, 3 types of bedding material (wheat straw, straw pellets, and wood shavings) used for horses were assessed according to their ammonia generation. Each type of bedding was used for 2 wk, with 3 repetitions. The mean ammonia concentrations within the stable were 3.07 +/- 0.23 mg/m(3) for wheat straw, 4.79 +/- 0.23 mg/m(3) for straw pellets, and 4.27 +/- 0.17 mg/m(3) for wood shavings. In Exp. 2, the effects of the mucking regimen on the generation of ammonia and PM10 from wheat straw (the bedding with the least ammonia generation in the previous experiment) were examined using 3 different daily regimens: 1) no mucking out, 2) complete mucking out, and 3) partial mucking out (removing only feces). The mean ammonia concentrations in the stable differed significantly among all 3 mucking regimens (P < 0.05). The greatest values were recorded when the stalls were mucked out completely every day [least squares means (LSM) = 2.25 +/- 0.1 mg/m(3)]. No mucking out resulted in an LSM of 1.92 +/- 0.1 mg of ammonia/m(3), whereas an LSM of 1.54 +/- 0.1 mg of ammonia/m(3) was found when the partial mucking out method was used. No mucking out also resulted in significantly less average PM10 (124.4 +/- 13.4 microg/m(3)) than in the other 2 regimens (P < 0.05). In Exp. 3, a 6-wk bedding regimen without mucking out was evaluated with regard to gas and airborne particle generation. The ammonia values were found not to increase constantly during the course of the 6-wk

  8. Solute transport in formations of very low permeability: profiles of stable isotope and dissolved noble gas contents of pore water in the Opalinus Clay, Mont Terri, Switzerland

    NASA Astrophysics Data System (ADS)

    Rübel, André P.; Sonntag, Christian; Lippmann, Johanna; Pearson, F. J.; Gautschi, Andreas

    2002-04-01

    Pore water profiles of water, stable isotope, and dissolved noble gas content have been determined across the Opalinus Clay and adjacent formations at the rock laboratory at Mont Terri. We have found enhanced helium contents (up to [ 4He] = 1 × 10 -4 cubic centimeters at standard pressure and temperature per gram of pore water) and argon isotope ratios ( 40Ar/ 36Ar ratios up to 334) due to accumulation of 4He and 40Ar produced in situ. The helium profile was found to be in steady state with respect to in situ production and diffusive loss into the adjacent limestones where groundwater circulates. From this profile a representative mean value of the apparent diffusion coefficient for helium in the pore water of the whole formation was derived for the first time to be D a = 3.5 × 10 -11 m 2 · s -1, which is more than two orders of magnitude lower than the diffusion coefficient D 0 in free water. The stable isotope profile, however, indicates a component of fossil marine pore water, which has not yet been replaced by molecular diffusion of meteoric water from the adjacent limestone and shale formations over the past 10 million years.

  9. Highly efficient and stable Au/CeO2-TiO2 photocatalyst for nitric oxide abatement: potential application in flue gas treatment.

    PubMed

    Zhu, Wei; Xiao, Shuning; Zhang, Dieqing; Liu, Peijue; Zhou, Hongjun; Dai, Wenrui; Liu, Fanfan; Li, Hexing

    2015-10-06

    In the present work, highly efficient and stable Au/CeO2-TiO2 photocatalysts were prepared by a microwave-assisted solution approach. The Au/CeO2-TiO2 composites with optimal molar ratio of Au/Ce/Ti of 0.004:0.1:1 delivered a remarkably high and stable NO conversion rate of 85% in a continuous flow reactor system under simulated solar light irradiation, which far exceeded the rate of 48% over pure TiO2. The tiny Au nanocrystals (∼1.1 nm) were well stabilized by CeO2 via strong metal-support bonding even it was subjected to calcinations at 550 °C for 6 h. These Au nanocrystals served as the very active sites for activating the molecule of nitric oxide and reducing the transmission time of the photogenerated electrons to accelerate O2 transforming to reactive oxygen species. Moreover, the Au-Ce(3+) interface formed and served as an anchoring site of O2 molecule. Then more adsorbed oxygen could react with photogenerated electrons on TiO2 surfaces to produce more superoxide radicals for NO oxidation, resulting in the improved efficiency. Meanwhile, O2 was also captured at the Au/TiO2 perimeter site and the NO molecules on TiO2 sites were initially delivered to the active perimeter site via diffusion on the TiO2 surface, where they assisted O-O bond dissociation and reacted with oxygen at these perimeter sites. Therefore, these finite Au nanocrystals can consecutively expose active sites for oxidizing NO. These synergistic effects created an efficient and stable system for breaking down NO pollutants. Furthermore, the excellent antisintering property of the catalyst will allow them for the potential application in photocatalytic treatment of high-temperature flue gas from power plant.

  10. Investigation of laser polarized xenon magnetic resonance

    NASA Technical Reports Server (NTRS)

    Walsworth, Ronald L.

    1998-01-01

    Ground-based investigations of a new biomedical diagnostic technology: nuclear magnetic resonance of laser polarized noble gas are addressed. The specific research tasks discussed are: (1) Development of a large-scale noble gas polarization system; (2) biomedical investigations using laser polarized noble gas in conventional (high magnetic field) NMR systems; and (3) the development and application of a low magnetic field system for laser polarized noble gas NMR.

  11. Electrical and kinetical aspects of homogeneous dielectric-barrier discharge in xenon for excimer lamps

    SciTech Connect

    Belasri, A.; Harrache, Z.

    2010-12-15

    A pulsed dielectric-barrier discharge in xenon has been simulated for operating conditions typical to excimer lamps, in which the discharge is considered spatially homogeneous. The computer model developed is based on the xenon plasma chemistry, the circuit, and the Boltzmann equations. First, the validity of the physical model was checked and compared to experimental and theoretical works, and then the model is applied in the case of a sinusoidal voltage at period frequencies in the range of 50 kHz-2 MHz. The results obtained with the present description are in good agreement with experimental measurements and one-dimensional fluid prediction in terms of electrical characteristics and vacuum ultraviolet (vuv) emission. The effect of operation voltage, power source frequency, dielectric capacitance, as well as gas pressure on the discharge efficiency and the 172, 150, and 147 nm photon generation, under the typical experimental operating conditions and for the case of a sinusoidal applied voltage, have been investigated and discussed. Calculations suggest that the overall conversion efficiency from electrical energy to vuv emission in the lamp is greater than 38%, and it will be very affected at high power source frequency and high gas pressure with a significant dependence on the dielectric capacitance.

  12. Production of nitrogen-free, hyperpolarized 129Xe gas

    NASA Astrophysics Data System (ADS)

    Ruth, U.; Hof, T.; Schmidt, J.; Fick, D.; Jänsch, H. J.

    129Xe with a nuclear polarization far above the thermal equilibrium value (hyperpolarized) is used in NMR studies to increase sensitivity. Gaseous, adsorbed, or dissolved xenon is utilized in physical, chemical, and medical applications. With the aim in mind to study single-crystal surfaces by NMR of adsorbed hyperpolarized 129Xe, three problems have to be solved. The reliable production of 129Xe with highest nuclear polarization possible, the separation of the xenon gas from the necessary quench gas nitrogen without polarization loss, and the dosing/delivery of small amounts of polarized xenon gas to a sample surface. Here we describe an optical pumping setup that regularly produces xenon gas with a 129Xe nuclear polarization of 0.7(+/-0.07). We show that a freeze-pump-thaw separation of xenon and nitrogen is feasible without a significant loss in xenon polarization. The nitrogen partial pressure can be suppressed by a factor of 400 in a single separation cycle. Dosing is achieved by using the low vapor pressure of a frozen hyperpolarized xenon sample.

  13. Breakdown characteristics of xenon HID Lamps

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia; Sato, Ayumu; Brates, Nanu; Noro, Koji; Kushner, Mark

    2009-10-01

    The breakdown characteristics of mercury free xenon high intensity discharge (HID) lamps exhibit a large statistical time lag often having a large scatter in breakdown voltages. In this paper, we report on results from a computational investigation of the processes which determine the ignition voltages for positive and negative pulses in commercial HID lamps having fill pressures of up to 20 atm. Steep voltage rise results in higher avalanche electron densities and earlier breakdown times. Circuit characteristics also play a role. Large ballast resistors may limit current to the degree that breakdown is quenched. The breakdown voltage critically depends on cathode charge injection by electric field emission (or other mechanisms) which in large part controls the statistical time lag for breakdown. For symmetric lamps, ionization waves (IWs) simultaneously develop from the bottom and top electrodes. Breakdown typically occurs when the top and bottom IWs converge. Condensed salt layers having small conductivities on the inner walls of HID lamps and on the electrodes can influence the ignition behavior. With these layers, IWs tend to propagate along the inner wall and exhibit a different structure depending on the polarity.

  14. Ethane-xenon mixtures under shock conditions

    NASA Astrophysics Data System (ADS)

    Flicker, Dawn; Magyar, Rudolph; Root, Seth; Cochrane, Kyle; Mattsson, Thomas

    2015-06-01

    Mixtures of light and heavy elements arise in inertial confinement fusion and planetary science. We present results on the physics of molecular scale mixing through a validation study of equation of state (EOS) properties. Density functional theory molecular dynamics (DFT/QMD) at elevated-temperature and pressure is used to obtain the properties of pure xenon, ethane, and various compressed mixture compositions along their principal Hugoniots. To validate the QMD simulations, we performed high-precision shock compression experiments using Sandia's Z-Machine. A bond tracking analysis of the simulations correlates the sharp rise in the Hugoniot curve with completion of dissociation in ethane. DFT-based simulation results compare well with experimental data and are used to provide insight into the dissociation as a function of mixture composition. Interestingly, we find that the compression ratio for complete dissociation is similar for ethane, Xe-ethane, polymethyl-pentene, and polystyrene, suggesting that a limiting compression exists for C-C bonded systems. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, Security Administration under contract DE-AC04-94AL85000.

  15. Ethane-xenon mixtures under shock conditions

    SciTech Connect

    Magyar, Rudolph J.; Root, Seth; Mattsson, Thomas; Cochrane, Kyle Robert; Flicker, Dawn G.

    2015-04-22

    Mixtures of light elements with heavy elements are important in inertial confinement fusion. We explore the physics of molecular scale mixing through a validation study of equation of state (EOS) properties. Density functional theory molecular dynamics (DFT-MD) at elevated temperature and pressure is used to obtain the thermodynamic state properties of pure xenon, ethane, and various compressed mixture compositions along their principal Hugoniots. In order to validate these simulations, we have performed shock compression experiments using the Sandia Z-Machine. A bond tracking analysis correlates the sharp rise in the Hugoniot curve with the completion of dissociation in ethane. Furthermore, the DFT-based simulation results compare well with the experimental data along the principal Hugoniots and are used to provide insight into the dissociation and temperature along the Hugoniots as a function of mixture composition. Interestingly, we find that the compression ratio for complete dissociation is similar for several compositions suggesting a limiting compression for C-C bonded systems.

  16. Ethane-xenon mixtures under shock conditions

    DOE PAGES

    Magyar, Rudolph J.; Root, Seth; Mattsson, Thomas; ...

    2015-04-22

    Mixtures of light elements with heavy elements are important in inertial confinement fusion. We explore the physics of molecular scale mixing through a validation study of equation of state (EOS) properties. Density functional theory molecular dynamics (DFT-MD) at elevated temperature and pressure is used to obtain the thermodynamic state properties of pure xenon, ethane, and various compressed mixture compositions along their principal Hugoniots. In order to validate these simulations, we have performed shock compression experiments using the Sandia Z-Machine. A bond tracking analysis correlates the sharp rise in the Hugoniot curve with the completion of dissociation in ethane. Furthermore, themore » DFT-based simulation results compare well with the experimental data along the principal Hugoniots and are used to provide insight into the dissociation and temperature along the Hugoniots as a function of mixture composition. Interestingly, we find that the compression ratio for complete dissociation is similar for several compositions suggesting a limiting compression for C-C bonded systems.« less

  17. Cerebral blood flow tomography with xenon-133

    SciTech Connect

    Lassen, N.A.

    1985-10-01

    Cerebral blood flow (CBF) can be measured tomographically by inhalation of Xenon-/sup 133/. The calculation is based on taking a sequence of tomograms during the wash-in and wash-out phase of the tracer. Due to the dynamic nature of the process, a highly sensitive and fast moving single photon emission computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical and investigative purposes. This article discusses in particular its use for the selection of patients with carotid occlusion for extracranial/intracranial bypass surgery, for detection of severe arterial spasm after aneurysm bleeding, and for detection of low flow areas during severe migraine attacks. The use of other tracers for CBF tomography using SPECT is summarized with emphasis on the /sup 99m/Tc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers.

  18. Gas-phase infrared and ab initio study of the unstable CF3CNO molecule and its stable furoxan ring dimer.

    PubMed

    Havasi, Balázs; Pasinszki, Tibor; Westwood, Nicholas P C

    2005-05-05

    The unstable trifluoroacetonitrile N-oxide molecule, CF3CNO, has been generated in high yield in the gas phase from CF3BrC=NOH and studied for the first time by gas-phase mid-infrared spectroscopy. Cold trapping of this molecule followed by slow warming forms the stable ring dimer, bis(trifluoromethyl)furoxan, also investigated by gas-phase infrared spectroscopy. The spectroscopy provides an investigation into the vibrational character of the two molecules, the assignments supported by calculations of the harmonic vibrational frequencies using in the case of CF3CNO both ab initio (CCSD(T)) and density functional theory (B3LYP) and B3LYP for the ring dimer. The ground-state structures of both molecules were investigated at the B3LYP level of theory, with CF3CNO further investigated using coupled-cluster. The CCSD(T) method suggests a slightly bent (C(s)) structure for CF3CNO, while the B3LYP method (with basis sets ranging from 6-311G(d) to cc-pVTZ) suggests a close-to-linear or linear CCNO chain. The CCN bending potential in CF3CNO was explored at the CCSD(T)(fc)/cc-pVTZ level, with the results suggesting that CF3CNO exhibits strong quasi-symmetric top behavior with a barrier to linearity of 174 cm(-1). Since both isomerization and dimerization are feasible loss processes for this unstable molecule, the relative stability of CF3CNO with respect to the known cyanate (CF3OCN), isocyanate (CF3NCO), and fulminate (CF3ONC) isomers and the mechanism of the dimerization process to the ring furoxan and other isomers were studied with density functional theory.

  19. A plan for directional dark matter sensitivity in high-pressure xenon detectors through the addition of wavelength shifting gaseous molecules

    NASA Astrophysics Data System (ADS)

    Gehman, V. M.; Goldschmidt, A.; Nygren, D.; Oliveira, C. A. B.; Renner, J.

    2013-10-01

    Xenon is an especially attractive candidate for both direct WIMP and 0νββ decay searches. Although the current trend has exploited the liquid phase, the gas phase xenon offers remarkable performance advantages for: energy resolution, topology visualization, and discrimination between electron and nuclear recoils. The NEXT-100 experiment, now under construction in the Canfranc Underground Laboratory, Spain, will operate at ~ 15 bars with 100 kg of 136Xe for the 0νββ decay search. We will describe recent results with small prototypes, indicating that NEXT-100 can provide about 0.5% FWHM energy resolution at the decay's Q value (2457.83 keV), as well as rejection of γ-rays with topological cuts. However, sensitivity goals for WIMP dark matter and 0νββ decay searches indicate the probable need for ton-scale active masses. NEXT-100 provides the springboard to reach this scale with xenon gas. We describe a scenario for performing both searches in a single, high-pressure, ton-scale xenon gas detector, without significant compromise to either. In addition, even in a single ton-scale, high-pressure xenon gas TPC, an intrinsic sensitivity to the nuclear recoil direction may exist. This plausibly offers an advance of more than two orders of magnitude relative to current low-pressure TPC concepts. We argue that, in an era of deepening fiscal austerity, such a dual-purpose detector may be possible at acceptable cost, within the time frame of interest, and deserves our collective attention.

  20. Effect of relativity on the ionization spectra of the xenon fluorides XeFn (n=2, 4, 6).

    PubMed

    Pernpointner, Markus; Cederbaum, Lorenz S

    2005-06-01

    Noble gas compounds exhibit special chemical bonding situations and have been investigated by various spectroscopic and theoretical techniques. In this work we calculate the ionization spectra of the xenon fluorides (XeF2,XeF4, and XeF6) in the valence and subvalence (down to Xe 4d) areas by application of the recently developed Dirac-Hartree-Fock one-particle propagator technique. In this technique, the relativistic (four-component) and electron correlation effects are computed simultaneously. The xenon compounds show considerable spin-orbit splitting strongly influencing the photoelectron spectrum not reproducible in prior calculations. Comparison to one-component methods is made and the occurring satellite structures are interpreted. The satellite structures can be attributed either to the breakdown of the one-particle picture or to a reflection of intra-atomic and interatomic Auger decay processes within the molecule.

  1. Chondritic Xenon in the Earth's mantle: new constrains on a mantle plume below central Europe

    NASA Astrophysics Data System (ADS)

    Caracausi, Antonio; Avice, Guillaume; Bernard, Peter; Furi, Evelin; Marty, Bernard

    2016-04-01

    data support the notion that the fraction of plutonium-derived Xe in plume sources (oceanic as well as continental) is higher than in the MORB source reservoir. Hence, the MORB - type reservoirs appear to be well distinguished and more degassed than the plume sources (oceanic as well as continental) supporting the heterogeneity of Earth's mantle. Finally this study highlights that xenon isotopes in the Eifel gas have preserved a chemical signature that is characteristic of other mantle plume sources. This is very intriguing because the presence of a mantle plume in this sector of Central Europe was already inferred from geophysical and geochemical studies(Buikin et al., 2005; Goes et al., 1999). Notably, tomographic images show a low-velocity structure down to 2000 km depth, representing deep mantle upwelling under central Europe, that may feed smaller upper-mantle plumes (Eifel volcanic district-Germany). References Buikin A., Trieloff M., HoppJ., Althaus T., Korochantseva E., Schwarz W.H. &Altherr R., (2005), Noble gas isotopessuggestdeepmantleplume source of late Cenozoicmaficalkalinevolcanism in Europe, Earth Planet. Sci. Lett. 230, 143-162. Goes S., Spakman W. &BijwaardH., (1999), A lowermantle source for centraleuropeanvolcanism, Science, 286, 1928-1931.G. Holland, M. Cassidy, C.J. Ballentine, Meteorite Kr in the Earth's mantle suggests a late accretionary source for the atmosphere, Science, 326, 1522-1525, (2009). Marty, B. Neon and xenon isotopes in MORB: implications for the Earth-atmosphere evolution. Earth Planet. Sci. Lett. 94, 45-56 (1989). Mukhopadhyay S., Early differentiation and volatile accretion recorded in deep-mantle neon and xenon
, Nature, 486, 101-106, (2013).

  2. Hyperpolarized Xenon-129 Magnetic Resonance Imaging of Functional Lung Microstructure

    NASA Astrophysics Data System (ADS)

    Dregely, Isabel

    Hyperpolarized 129Xe (HXe) is a non-invasive contrast agent for lung magnetic resonance imaging (MRI), which upon inhalation follows the functional pathway of oxygen in the lung by dissolving into lung tissue structures and entering the blood stream. HXe MRI therefore provides unique opportunities for functional lung imaging of gas exchange which occurs from alveolar air spaces across the air-blood boundary into parenchymal tissue. However challenges in acquisition speed and signal-to-noise ratio have limited the development of a HXe imaging biomarker to diagnose lung disease. This thesis addresses these challenges by introducing parallel imaging to HXe MRI. Parallel imaging requires dedicated hardware. This work describes design, implementation, and characterization of a 32-channel phased-array chest receive coil with an integrated asymmetric birdcage transmit coil tuned to the HXe resonance on a 3 Tesla MRI system. Using the newly developed human chest coil, a functional HXe imaging method, multiple exchange time xenon magnetization transfer contrast (MXTC) is implemented. MXTC dynamically encodes HXe gas exchange into the image contrast. This permits two parameters to be derived regionally which are related to gas-exchange functionality by characterizing tissue-to-alveolar-volume ratio and alveolar wall thickness in the lung parenchyma. Initial results in healthy subjects demonstrate the sensitivity of MXTC by quantifying the subtle changes in lung microstructure in response to orientation and lung inflation. Our results in subjects with lung disease show that the MXTC-derived functional tissue density parameter exhibits excellent agreement with established imaging techniques. The newly developed dynamic parameter, which characterizes the alveolar wall, was elevated in subjects with lung disease, most likely indicating parenchymal inflammation. In light of these observations we believe that MXTC has potential as a biomarker for the regional quantification of 1

  3. Analysis of the properties of the molecular-cluster xenon mixture in the mesoscopic phase transition region

    NASA Astrophysics Data System (ADS)

    Kurlapov, L. I.; Kassymov, A. B.

    2016-04-01

    We report on the results of calculation of the concentrations of cluster subcomponents in a molecular-cluster xenon mixture at temperatures and pressures at which the gas experiences a mesoscopic phase transition. The existence of such a transition follows from singularities of the temperature dependence of viscosity, from the behavior of the cluster thermodiffusion coefficient, and from the features of the distributions of cluster subcomponents in the centrifuge. The mesoscopic phase transition is manifested in the intermediate position of the molecular-cluster mixture between the gas and the liquid judging from its properties in the transition region.

  4. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

    DOE PAGES

    Akerib, D. ?S.; Alsum, S.; Ara?jo, H. ?M.; ...

    2017-01-19

    This study presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronicmore » recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with 3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.« less

  5. XEMIS: A liquid xenon detector for medical imaging

    NASA Astrophysics Data System (ADS)

    Gallego Manzano, L.; Bassetto, S.; Beaupere, N.; Briend, P.; Carlier, T.; Cherel, M.; Cussonneau, J.-P.; Donnard, J.; Gorski, M.; Hamanishi, R.; Kraeber Bodéré, F.; Le Ray, P.; Lemaire, O.; Masbou, J.; Mihara, S.; Morteau, E.; Scotto Lavina, L.; Stutzmann, J.-S.; Tauchi, T.; Thers, D.

    2015-07-01

    A new medical imaging technique based on the precise 3D location of a radioactive source by the simultaneous detection of 3γ rays has been proposed by Subatech laboratory. To take advantage of this novel technique a detection device based on a liquid xenon Compton telescope and a specific (β+, γ) emitter radionuclide, 44Sc, are required. A first prototype of a liquid xenon time projection chamber called XEMIS1 has been successfully developed showing very promising results for the energy and spatial resolutions for the ionization signal in liquid xenon, thanks to an advanced cryogenics system, which has contributed to a high liquid xenon purity with a very good stability and an ultra-low noise front-end electronics (below 100 electrons) operating at liquid xenon temperature. The very positive results obtained with XEMIS1 have led to the development of a second prototype for small animal imaging, XEMIS2, which is now under development. To study the feasibility of the 3γ imaging technique and optimize the characteristics of the device, a complete Monte Carlo simulation has been also carried out. A preliminary study shows very positive results for the sensitivity, energy and spatial resolutions of XEMIS2.

  6. Signal yields, energy resolution, and recombination fluctuations in liquid xenon

    NASA Astrophysics Data System (ADS)

    Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bramante, R.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

    2017-01-01

    This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with 3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.

  7. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  8. Oxygen transport in the internal xenon plasma of a dispenser hollow cathode

    SciTech Connect

    Capece, Angela M. Shepherd, Joseph E.; Polk, James E.; Mikellides, Ioannis G.

    2014-04-21

    Reactive gases such as oxygen and water vapor modify the surface morphology of BaO dispenser cathodes and degrade the electron emission properties. For vacuum cathodes operating at fixed temperature, the emission current drops rapidly when oxygen adsorbs on top of the low work function surface. Previous experiments have shown that plasma cathodes are more resistant to oxygen poisoning and can operate with O{sub 2} partial pressures one to two orders of magnitude higher than vacuum cathodes before the onset of poisoning occurs. Plasma cathodes used for electric thrusters are typically operated with xenon; however, gas phase barium, oxygen, and tungsten species may be found in small concentrations. The densities of these minor species are small compared with the plasma density, and thus, their presence in the discharge does not significantly alter the xenon plasma parameters. It is important, however, to consider the transport of these minor species as they may deposit on the emitter surface and affect the electron emission properties. In this work, we present the results of a material transport model used to predict oxygen fluxes to the cathode surface by solving the species conservation equations in a cathode with a 2.25 mm diameter orifice operated at a discharge current of 15 A, a Xe flow rate of 3.7 sccm, and 100 ppm of O{sub 2}. The dominant ionization process for O{sub 2} is resonant charge exchange with xenon ions. Ba is effectively recycled in the plasma; however, BaO and O{sub 2} are not. The model shows that the oxygen flux to the surface is not diffusion-limited; therefore, the high resistance to oxygen poisoning observed in plasma cathodes likely results from surface processes not considered here.

  9. Fluid modeling of a high-voltage nanosecond pulsed xenon microdischarge

    SciTech Connect

    Levko, Dmitry; Raja, Laxminarayan L.

    2016-07-15

    A computational modeling study of high-voltage nanosecond pulsed microdischarge in xenon gas at 10 atm is presented. The discharge is observed to develop as two streamers originating from the cathode and the anode, and propagating toward each other until they merge to form a single continuous discharge channel. The peak plasma density obtained in the simulations is ∼10{sup 24 }m{sup −3}, i.e., the ionization degree of plasma does not exceed 1%. The influence of the initial gas pre-ionization is established. It is seen that an increase in the seeded plasma density results in an increase in the streamer propagation velocity and an increase in the plasma density obtained after the merging of two streamers.

  10. Hypersatellite and satellite transitions in xenon atoms

    NASA Astrophysics Data System (ADS)

    Ilakovac, K.; Vesković, M.; Horvat, V.; Kauić, S.

    1990-10-01

    Decay of double-K-shell-vacancy states in xenon atoms, created in the decay of 131Cs, was investigated. The measurements were performed with a pair of germanium detectors, a fast-slow coincidence system, and a three-parameter pulse-height analyzer. In the analysis of the two-dimensional E1-E2 spectrum, improved least-squares routines were applied. The following results were derived: the probability of creation of a double K-shell vacancy per 131Cs decay, PKK=(1.48+/-0.35)×10-5 the hypersatellite energy shifts Δh(Kα)=(653+/-20) eV, Δh(Kβ1)=(834+/-39) eV, and Δh(Kβ2)=(903+/-81) eV; the average values of the satellite energy shifts due to the presence of an L3- or L2-shell spectator vacancy Δs(KαL-1)=(80+/-15) eV, Δs(Kβ1L-1)=(169+/-34) eV, and Δs(Kβ2L-1)=(261+/-81) eV; the intensity ratios of the hypersatellite transitions, I(Kαh2)/I(Kαh1)=0.94+/-0.18, I(Kβh1)/I(Kαh1)=0.36+/-0.06, and I(Kβh2)/ I(Kαh1)=0.09+/-0.04 the intensity ratios of the satellite transitions I(Kα2L-1)/I(Kα1L-1)=0.44+/-0.10 and 0.44+/-0.09 for an L3 and L2 spectator vacancy, respectively; and the intensity ratios of some other satellite transitions.

  11. Stable Cu2O nanocrystals grown on functionalized graphene sheets and room temperature H2S gas sensing with ultrahigh sensitivity

    NASA Astrophysics Data System (ADS)

    Zhou, Lisha; Shen, Fangping; Tian, Xike; Wang, Donghong; Zhang, Ting; Chen, Wei

    2013-01-01

    Stable Cu2O nanocrystals of around 3 nm were uniformly and densely grown on functionalized graphene sheets (FGS), which act as molecular templates instead of surfactants for controlled nucleation; the distribution density of nanocrystals can be easily controlled by FGS with different C/O ratios. The nanocomposite displays improved stability of the crystalline phase in wet air, which is attributed to finite-size effects that the high-symmetry crystalline phase is to be more stable at smaller size. Meanwhile, we conjecture that the oxygen adsorbed on the interfacial surface prefers to extract electrons from FGS, thus the interfacial bonding also makes a contribution in alleviating the process of corrosion to some extent. More importantly, the Cu2O-FGS nanocomposite based sensor realizes room temperature sensing to H2S with fantastic sensitivity (11%); even at the exposed concentration of 5 ppb, the relative resistance changes show good linearity with the logarithm of the concentration. The enhancement of sensitivity is attributed to the synergistic effect of Cu2O and FGS; on the one hand, surfactant-free capped Cu2O nanocrystals display higher surface activity to adsorb gas molecules, and on the other hand, FGS acting as conducting network presents greater electron transfer efficiency. These observations show that the Cu2O-FGS nanocomposite based sensors have potential applications for monitoring air pollution at room temperature with low cost and power consumption.Stable Cu2O nanocrystals of around 3 nm were uniformly and densely grown on functionalized graphene sheets (FGS), which act as molecular templates instead of surfactants for controlled nucleation; the distribution density of nanocrystals can be easily controlled by FGS with different C/O ratios. The nanocomposite displays improved stability of the crystalline phase in wet air, which is attributed to finite-size effects that the high-symmetry crystalline phase is to be more stable at smaller size. Meanwhile

  12. Xenon stability analysis using the generalized nyquist criterion

    SciTech Connect

    Choi, Yoocho; Park, Gooncherl; Chung, Changhyun ); Park, Jongkyun

    1990-06-01

    Xenon-induced spatial power oscillations caused by control rod movement may cause control problems in nuclear power plant operation. Many studies have been performed to assess the xenon stability analysis using the time-domain technique or the frequency-domain technique for the single-input/single-output (SISO) system. However, those methods are too complicated and thus too time consuming, or too simple to provide results according to control rod movement in a certain position. This study analyzes xenon axial stability using the modal expansion technique in the frequency domain with the generalized Nyquist criterion, which is suitable for a multi-input/multi-output (MIMO) system. To examine this model, an axial stability analysis has been performed for the pressurized water reactor core of YGN-1 in Korea. The studied design parameters are power level, control rod position, and core average burnup.

  13. Liquid xenon purification, de-radonation (and de-kryptonation)

    SciTech Connect

    Pocar, Andrea

    2015-08-17

    Liquid xenon detectors are at the forefront of rare event physics, including searches for neutrino-less double beta decay and WIMP dark matter. The xenon for these experiments needs to be purified from chemical impurities such as electronegative atoms and molecules, which absorb ionization electrons, and VUV (178 nm) scintillation light-absorbing chemical species. In addition, superb purification from radioactive impurities is required. Particularly challenging are radioactive noble isotopes ({sup 85}Kr,{sup 39,42}Ar,{sup 220,222}Rn). Radon is a particularly universal problem, due to the extended decay sequence of its daughters and its ubiquitous presence in detector materials. Purification and de-radonation of liquid xenon are addressed with particular focus on the experience gained with the EXO-200 neutrino-less double beta decay detector.

  14. Xenon bubble chambers for direct dark matter detection

    NASA Astrophysics Data System (ADS)

    Levy, C.; Fallon, S.; Genovesi, J.; Khaitan, D.; Klimov, K.; Mock, J.; Szydagis, M.

    2016-03-01

    The search for dark matter is one of today's most exciting fields. As bigger detectors are being built to increase their sensitivity, background reduction is an ever more challenging issue. To this end, a new type of dark matter detector is proposed, a xenon bubble chamber, which would combine the strengths of liquid xenon TPCs, namely event by event energy resolution, with those of a bubble chamber, namely insensitivity to electronic recoils. In addition, it would be the first time ever that a dark matter detector is active on all three detection channels, ionization and scintillation characteristic of xenon detectors, and heat through bubble formation in superheated fluids. Preliminary simulations show that, depending on threshold, a discrimination of 99.99% to 99.9999+% can be achieved, which is on par or better than many current experiments. A prototype is being built at the University at Albany, SUNY. The prototype is currently undergoing seals, thermal, and compression testing.

  15. Supernova Neutrino Physics with Xenon Dark Matter Detectors

    NASA Astrophysics Data System (ADS)

    Reichard, Shayne; Lang, Rafael F.; McCabe, Christopher; Selvi, Marco; Tamborra, Irene

    2017-09-01

    The dark matter experiment XENON1T is operational and sensitive to all flavors of neutrinos emitted from a supernova. We show that the proportional scintillation signal (S2) allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the SN burst. XENON1T (XENONnT and LZ; DARWIN) will be sensitive to a SN burst up to 25 (40; 70) kpc from Earth at a significance of more than 5σ, observing approximately 35 (123; 704) events from a 27 M ⊙ SN progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of all flavors, to constrain the total explosion energy, and to reconstruct the SN neutrino light curve. Our results suggest that a large xenon detector such as DARWIN will be competitive with dedicated neutrino telescopes, while providing complementary information that is not otherwise accessible.

  16. Quantitative analysis of aberrant fatty acid composition of zebrafish hepatic lipids induced by organochlorine pesticide using stable isotope-coded transmethylation and gas chromatography-mass spectrometry.

    PubMed

    Zhong, Hongying; Dong, Linjie; Dong, Qingjian; Ke, Changshu; Fu, Jieying; Wang, Xiaoli; Liu, Cong; Dai, Ling

    2012-07-01

    Organochlorine pesticides have been extensively used worldwide for agricultural purposes. Due to their resistance to metabolism, a major public health concern has been raised. Aberrant hepatic lipid composition has been a hallmark of many liver diseases associated with exposure to various toxins and chemicals. And thus lots of efforts have been focused on the development of analytical techniques that can rapidly and quantitatively determine the changes in fatty acid composition of hepatic lipids. In this work, changes in fatty acid composition of hepatic lipids in response to DDT (dichlorodiphenyltrichloroethane) exposure were quantitatively analyzed by a gas chromatography-mass spectrometric approach based on stable isotope-coded transmethylation. It has been quantitatively demonstrated that polyunsaturated fatty acids including C20:3n3, C20:4n6, and C22:6n3 decrease in response to DDT exposure. However, saturated long chain fatty acids including C16:0, C18:0, as well as monounsaturated long chain fatty acid C18:1n9 consistently increase in a DDT-concentration-dependent manner. In particular, much higher changes in the level of hepatic C16:0 and C18:0 for male fish were observed than that for female fish. These experimental results are in accordance with qualitative histopathological analysis that revealed liver morphological alterations. The stable isotope-coded mass spectrometric approach provides a reliable means for investigating hepatotoxicity associated with fatty acid synthesis, desaturation, mitochondrial beta-oxidation, and lipid mobilization. It should be useful in elucidation of hepatotoxic mechanisms and safety assessment of environmental toxins.

  17. Stable, tunable, and single-mode operation of an erbium-doped fibre laser system using a saturable absorber for gas spectroscopy applications

    NASA Astrophysics Data System (ADS)

    Arsad, Norhana; Stewart, George

    2009-02-01

    We present an erbium doped fibre ring laser system to realize single frequency lasing by incorporating a reflector with ~2m of un-pumped polarization-maintaining erbium-doped fibre to act as a saturable absorber. Depending on the particular requirements, the fibre reflector may be a fibre Bragg grating (FBG), loop mirror (LM) or a reflective coating on the fibre end. In this way, a transient grating is formed in the saturable absorber which acts as a narrow-band optical filter, reducing the number of modes over which the laser can operate and hence suppressing mode hopping in the cavity. Polarization-maintaining (PM) components are used throughout the system, except for the EDFA, and a polarization controller is used for enhancing stability and to ensure that the state of polarization is properly aligned. With this system we have observed a long period of stable, narrow line-width and single mode operation, tuneable over 30nm. The intended application is for gas spectroscopy using wavelength scanning and pump modulation. A Sagnac loop filter (SLF) can be used to scan the centre wavelength over a gas absorption line while the pump modulation produces an amplitude modulated signal on the output, suitable for detection by a lock-in (phase-sensitive) amplifier. The method is useful for the recovery of absorption line-shapes in the near-IR where the overtone absorption lines are weak. Compared with the use of a traditional DFB laser source, the fibre laser offers the advantages of a much broader tuning range and recovery of distortion-free line-shapes since wavelength and amplitude modulation may be performed independently.

  18. Xenon purity analysis for EXO-200 via mass spectrometry

    NASA Astrophysics Data System (ADS)

    Dobi, A.; Hall, C.; Slutsky, S.; Yen, Y.-R.; Aharmin, B.; Auger, M.; Barbeau, P. S.; Benitez-Medina, C.; Breidenbach, M.; Cleveland, B.; Conley, R.; Cook, J.; Cook, S.; Counts, I.; Craddock, W.; Daniels, T.; Davis, C. G.; Davis, J.; deVoe, R.; Dixit, M.; Dolinski, M. J.; Donato, K.; Fairbank, W.; Farine, J.; Fierlinger, P.; Franco, D.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Green, C.; Hagemann, C.; Hall, K.; Hallman, D.; Hargrove, C.; Herrin, S.; Hughes, M.; Hodgson, J.; Juget, F.; Karelin, A.; Kaufman, L. J.; Kuchenkov, A.; Kumar, K.; Leonard, D. S.; Lutter, G.; Mackay, D.; MacLellan, R.; Marino, M.; Mong, B.; Montero Díez, M.; Morgan, P.; Müller, A. R.; Neilson, R.; Odian, A.; O'Sullivan, K.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rivas, A.; Rollin, E.; Rowson, P. C.; Sabourov, A.; Sinclair, D.; Skarpaas, K.; Stekhanov, V.; Strickland, V.; Swift, M.; Twelker, K.; Vuilleumier, J.-L.; Vuilleumier, J.-M.; Weber, M.; Wichoski, U.; Wodin, J.; Wright, J. D.; Yang, L.

    2012-05-01

    We describe purity measurements of the natural and enriched xenon stockpiles used by the EXO-200 double beta decay experiment based on a mass spectrometry technique. The sensitivity of the spectrometer is enhanced by several orders of magnitude by the presence of a liquid nitrogen cold trap, and many impurity species of interest can be detected at the level of one part-per-billion or better. We have used the technique to screen the EXO-200 xenon before, during, and after its use in our detector, and these measurements have proven useful. This is the first application of the cold trap mass spectrometry technique to an operating physics experiment.

  19. A liquid Xenon detector for micro-PET

    NASA Astrophysics Data System (ADS)

    Retière, F.

    2010-11-01

    Liquid Xenon is a very promising technology for the new generation of Positron Emission Tomography detectors. The performance achieved by combining both scintillation light and ionization charge readout significantly exceeds the capabilities of conventional crystal based detectors. In these proceedings, we show that we achieved a 9.6% (full width half maximum) for 511 keV photons by combining light and charge. Then, we investigate the performance of a liquid Xenon micro-PET detector by running simulations and relying on a Compton reconstruction algorithm. The image quality is far superior to the existing FOCUS 120 micro-PET.

  20. The uses of helium and xenon in current clinical practice.

    PubMed

    Harris, P D; Barnes, R

    2008-03-01

    The noble gases have always been an enigma. Discovered late in the history of chemistry and in seemingly small quantities in our atmosphere, they are some of the most unreactive elements known. However, despite being extremely inert, the noble gases (helium, neon, argon, krypton, xenon and radon) have found diverse and ever expanding applications in medicine. Of all of them, the gases that have found the greatest number of uses in the field of anaesthesia and related specialties are helium and xenon. This review focuses on the history of the discovery of both gases, their unique physicochemical properties and describes their uses in clinical practice with particular emphasis on those applicable to anaesthesia.