WorldWideScience

Sample records for aperture deuterium gas

  1. Determination of atom percent deuterium in deuterium gas using a vibrating-probe density meter

    International Nuclear Information System (INIS)

    Atom percent deuterium may be effectively analyzed in a mixture of hydrogen and deuterium gases from the density determination of the mixture of water-heavy water which is formed after the gas sample is converted to an oxide and condensed. The density can be accurately measured by using a vibrating-tube density meter which is standardized with air and pure water or other density standards. This deuterium determination requires no empirical standardization against known deuterium standards. The sample gas in a helium carrier is passed through a hot copper oxide tube; the hydrogen and deuterium oxides are condensed in a liquid-nitrogen cooled collection bulb, which was designed for effective entrapment and prevention of sample exposure to the atmosphere

  2. Rotating Aperture System

    Science.gov (United States)

    Rusnak, Brian; Hall, James M.; Shen, Stewart; Wood, Richard L.

    2005-01-18

    A rotating aperture system includes a low-pressure vacuum pumping stage with apertures for passage of a deuterium beam. A stator assembly includes holes for passage of the beam. The rotor assembly includes a shaft connected to a deuterium gas cell or a crossflow venturi that has a single aperture on each side that together align with holes every rotation. The rotating apertures are synchronized with the firing of the deuterium beam such that the beam fires through a clear aperture and passes into the Xe gas beam stop. Portions of the rotor are lapped into the stator to improve the sealing surfaces, to prevent rapid escape of the deuterium gas from the gas cell.

  3. Process for the production of hydrogen/deuterium-containing gas

    International Nuclear Information System (INIS)

    A process for the production of hydrogen/deuterium-containing gas is described in which the enriched condensate obtained from the production of a hydrogen/deuterium-containing gas mixture is collected and subjected to a direct exchange of isotopes with the feedsteam admitted to the process. Such condensate can be brought into direct exchange of isotopes with the gas water vapor mixture within the process, viz. ahead of the CO conversion section. The exchange of isotopes may be performed according to the counter-current principle. If it is intended to maintain in the hydrogen/deuterium-containing gas a certain definite content of water vapor whose phase condition is superior to the condition achieved when using normal cooling water, this gas, at least 0.6 kg/m3 of gas, is subjected to an exchange of isotopes with the water fed additionally into the process

  4. Gas swelling and deuterium distribution in beryllium implanted with deuterium ions

    Energy Technology Data Exchange (ETDEWEB)

    Chernikov, V.N.; Alimov, V.Kh.; Zakharov, A.P. [Institute of Physical Chemistry, Moscow (Russian Federation)

    1995-09-01

    An extensive TEM study of the microstructure of Be TIP-30 irradiated with 3 and 10 keV D ions up to fluences, {Phi}, in the range from 3 x 10{sup 20} to 8 x 10{sup 21} D/m{sup 2} at temperatures T{sub irr} = 300 K, 500 K and 700 K has been carried out. Depth distributions of deuterium in the form of separate D atoms and D{sub 2} molecules have been investigated by means of SIMS and RGA methods, correspondingly. D ion irradiation is accompanied by blistering and gives rise to different kind of destructions depending mainly on the irradiation temperature. Irradiation with D ions at 300 K leads to the formation of tiny highly pressurized D{sub 2} bubbles reminiscent of He bubbles in Be. Under 3 keV D ion irradiation D{sub 2} bubbles ({bar r}{sub b} {approx} 0.7 nm) appear at a fluence as low as 3x10{sup 20} D/m{sup 2}. Irradiation at 500 K results in the development, along with relatively small facetted bubbles, of larger oblate gas-filled cavities accumulating most of injected D atoms and providing for much higher gas swelling values as compared to irradiation at 300 K. The increase of D and/or T{sub irr}, to 700 K causes the further coarsening of large cavities which are transformed into sub-surface labyrinth structures. D and He ion implantation leads to the enhanced growth of porous microcrystalline layers of c.p.h.-BeO oxide with a microstructure which differs considerably from that of oxide layers on electropolished surfaces of Be. Based on the analysis of experimental data questions of deuterium reemission, thermal desorption and trapping in Be have been discussed in detail.

  5. Apertures

    CERN Document Server

    Hansen, R C

    2014-01-01

    Microwave Scanning Antennas, Volume I: Apertures is a comprehensive account of phased arrays, multiple beam arrays, time domain and synthetic apertures, and adaptive antennas. Advances in continuous apertures and near field theory are discussed. Low noise and monopulse apertures, optical scanners, and large radomes are also covered, along with radio astronomy instruments and associated theory.Comprised of five chapters, this volume begins with an overview of aperture theory as well as aperture distributions and near field theory. The second and third chapters deal with mechanically steered and

  6. Comparison of Deuterium-Deuterium-Deuterium and Neon-Deuterium-Deuterium Triple Shell Gas-Puff Z-pinch on the Level of 3 MA

    Science.gov (United States)

    Rezac, K.; Klir, Daniel; Kubes, P.; Kravarik, J.; Shishlov, A.; Labetsky, A.; Ratakhin, N.

    2012-10-01

    The experiments of a triple shell gas-puff Z-pinch were carried out on the GIT-12 generator at IHCE in Tomsk during the April-May-June campaign in 2012. We diagnosed 17 Z-pinch shots where the triple D2-D2-D2 (with the linear mass in the range of 50 - 255 μg/cm) and Ne-D2-D2 (with the linear mass in the range of 110 - 285 μg/cm) gas-puffs with diameter of 160 mm / 80 mm / 30 mm were mostly used as loads. This contribution is focused on the comparison of the results obtained by X-ray and neutron diagnostics, especially to the difference in reconstructed neutron energy spectra and obtained neutron yields (with the maximum of 3.3 x10^11 neutrons/shot on a current level of 2.5 MA). The time correlations with other diagnostics such as electrical characteristics, a visible streak camera and MCP frames are also presented.

  7. Effect of noble gas ion pre-irradiation on deuterium retention in tungsten

    Science.gov (United States)

    Cheng, L.; Zhao, Z. H.; De Temmerman, G.; Yuan, Y.; Morgan, T. W.; Guo, L. P.; Wang, B.; Zhang, Y.; Wang, B. Y.; Zhang, P.; Cao, X. Z.; Lu, G. H.

    2016-02-01

    Impurity seeding of noble gases is an effective way of decreasing the heat loads onto the divertor targets in fusion devices. To investigate the effect of noble gases on deuterium retention, tungsten targets have been implanted by different noble gas ions and subsequently exposed to deuterium plasma. Irradiation induced defects and deuterium retention in tungsten targets have been characterized by positron annihilation Doppler broadening and thermal desorption spectroscopy. Similar defect distributions are observed in tungsten irradiated by neon and argon, while it is comparatively low in the case of helium. The influence of helium pre-irradiation on deuterium trapping is found to be small based on the desorption spectrum compared with that of the pristine one. Neon and argon pre-irradiation leads to an enhancement of deuterium trapping during plasma exposure. The influence on deuterium retention is found to be argon > neon > helium when comparing at a similar crystal damage level.

  8. Some experiments on cold fusion by deuterium hydrogen gas infusion in titanium metal alloy

    International Nuclear Information System (INIS)

    New results on cold fusion are reported where three different experimental situations have been tried: a) deuterium gas loaded titanium; b) deuterium gas loaded Ti0.8Zr0.2CrMn alloy and c) titanium and the Ti0.8Zr0.2CrMn alloy loaded with a mixture of deuterium and hydrogen gases. With these experiments, new thermodynamical non equilibrium conditions were achieved and the possibility of cold fusion between protons and deuterons was also tested. Three independent neutron detectors and one NaI(Tl) were utilized. Despite some large values reported in the literature for the fusion rate, an upper limit of only 8 x 10-24 fusions/sper deuterium pair or per deuterium-hydrogen pair was determined within the attained accuracy. (author)

  9. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film

    International Nuclear Information System (INIS)

    High-resolution mass spectrometer was used to analyze the gas from a deuterium flux maker. Mass 3 components were analyzed carefully to inspect any anomaly from the deuterium gas permeating a palladium film. Mass 3 component is confirmed again, but more work is needed to separate the signal of the helium-3 (if any) from the heavy background of D-T molecules. (author)

  10. Phenomenological nuclear reaction description in deuterium-saturated palladium and synthesized structure in dense deuterium gas under γ-quanta irradiation

    International Nuclear Information System (INIS)

    The observed phenomena on the changes of chemical compositions in our previous reports allowed us to develop a phenomenological nuclear fusion-fission model with taking into consideration the elastic and inelastic scattering of photoprotons and photoneutrons, heating of surrounding deuterium nuclei, following D-D fusion reactions and fission of middle-mass nuclei by 'hot' protons, deuterons and various-energy neutrons. Such chain processes could produce the necessary number of neutrons, 'hot' deuterons for explanation of the observed experimental results. The developed approach can be a basis for creation of deuterated nuclear fission reactors (DNFR) with high-density deuterium gas and so-called deuterated metals. Also, the developed approach can be used for the study of nuclear reactions in high-density deuterium or tritium gases and deuterated metals

  11. D2 gas-filled blisters on deuterium-bombarded tungsten

    International Nuclear Information System (INIS)

    Most of spherical blisters formed by deuterium (D) bombardment (38 eV/D) up to 3 x 1024 D/m2 at 300 K on polycrystalline tungsten are fully elastic deformations. This has been proven by opening individual blisters with a focused ion beam and in situ observation of their complete relaxation by scanning electron microscopy. The D2 gas filling is confirmed by observing simultaneously the D2 puff. The gas pressure is causal for the stability of such spherical blisters after implantation and the gas release leads to sudden relaxation. The dilatation of the blister cap by trapped D can be excluded as cause for the blisters.

  12. Deuterium retention in graphite and its removal by inert gas glow discharge

    International Nuclear Information System (INIS)

    The hydrogen isotope retention and its removal by inert gas glow discharge for graphite was investigated by residual gas analysis. The amount of retained hydrogen isotope in graphite during the deuterium glow discharge was about 1.0×1017 cm2, which was one order of magnitude larger than that in 316L stainless steel or tungsten. The removal ratio of hydrogen isotope by helium, neon and argon glow discharge cleaning were 49%, 22% and 6% respectively. These removal ratios were similar to those for the stainless steel, but larger than the tungsten. The removal ratio in graphite can be explained by both the depth distribution of incident deuterium in the materials and the etching depth. (author)

  13. Evidence for production of tritium via cold fusion reactions in deuterium gas loaded in palladium (Paper No. B4)

    International Nuclear Information System (INIS)

    Experiments were conducted to observe cold fusion reaction in deuterium gas loaded palladium. Two types of palladium samples were used. One was commercially procured palladium-silver alloy without any surface treatment and the other was palladium black powder prepared from PdCl2. Deuterium absorption by the powder was very fast, but the same was slow in the alloy. The loading procedure was first to heat the sample to 600degC for two hours under vacuum of better than 10-5mm, cooling to room temperature followed by contact with deuterium gas at 1 atm. and finally keeping for equilibration for several hours in atmosphere free of both moisture and oxygen. Samples were then kept in contact with distilled water for a few hours to extract tritium by isotopic exchange into the water. Tritium activity was measured by liquid scintillation counting. Tritium/deuterium ratio was found to be two-three times more in the case of Pd-Ag foils as compared to Pd powder. The ratio is in the range 10-12 to 10-11 which is more than two orders of magnitude higher than that in the initial deuterium gas used for loading. Autoradiographs of Pd-Ag foils loaded with deuterium showed fogging due to tritium betas. These observations show that deuterium loading of Pd also induces cold fusion in Pd lattice. (M.G.B.). 5 refs., 1 tab., 1 fig

  14. Nuclear spin relaxation of D2 in deuterium gas and in solid argon

    International Nuclear Information System (INIS)

    Nuclear spin relaxation times have been measured for molecular deuterium, both as a pure gas and as a dilute impurity in a host matrix of solid argon. In the gas, T1 was measured as function of temperature and of the density p, over the ranges from 25 to 125 K and from 2 to 12 amagat, and the measurements are consistent with a model of a primary relaxation mechanism resulting from an intramolecular interaction with the molecular angular momentum, which as fluctuating components because of collisions between gas molecules. T1 and T2 of p-D2 were measured for dilute mixtures of molecular deuterium in solid argon at temperatures from 5.6 to 55 K. The primary relaxation mechanism in these mixtures is, as for the gaseous samples, the intramolecular interaction with the fluctuating molecular spin; in this case, the molecular spin fluctuations are caused by phonon induced modulation of electric field gradients at the molecular sites. The results can described by Fedders' calculation of the intramolecular interaction, and by the Van Kronendank and Walker model of anharmonic phonon interactions with the molecular quadrupole moment. The mixture samples were mixed in the liquid phase, and then frozen. T1 was also measured in the liquid mixtures, and line shape spectra were recorded. A shift of the deuterium resonance frequency was observed between gas phase and liquid phase mixtures. All of the relaxation time measurements were performed using pulsed NMR techniques, at a frequency of 55 MHz in a 8.5 T superconducting magnet. A liquid helium flow cryostat system was used to control the temperature of the samples

  15. Pion transfer from hydrogen to deuterium in H2+D2 gas mixtures

    International Nuclear Information System (INIS)

    The transfer of negative pions from pionic hydrogen to deuterium has been investigated in gas mixtures of H2 and D2 as a function of the D2 concentration. The concentration dependence of the transfer rate was fitted using a phenomenological model with two parameters. For C → ∞ (32±3)% of the pions undergo transfer. The fitted parameters reflect the ratio of pion capture to pion transfer in collisions of pionic hydrogen with protons or deuterons. No pressure dependence for pion transfer was found. (Author) 33 refs., 3 tabs., 7 figs

  16. Two-chamber hydrogen generation and application: access to pressurized deuterium gas.

    Science.gov (United States)

    Modvig, Amalie; Andersen, Thomas L; Taaning, Rolf H; Lindhardt, Anders T; Skrydstrup, Troels

    2014-06-20

    Hydrogen and deuterium gas were produced and directly applied in a two-chamber system. These gaseous reagents were generated by the simple reaction of metallic zinc with HCl in water for H2 and DCl in deuterated water for D2. The setup proved efficient in classical Pd-catalyzed reductions of ketones, alkynes, alkenes, etc. in near-quantitative yields. The method was extended to the synthesis and isotope labeling of quinoline and 1,2,3,4-tetrahydroquinoline derivatives. Finally, CX-546 and Olaparib underwent efficient Ir-catalyzed hydrogen isotope exchange reactions. PMID:24870212

  17. Deuterium Gas-Puff Z-Pinch on GIT-12 Generator

    Science.gov (United States)

    Klir, Daniel; Kravarik, Jozef; Kubes, Pavel; Rezac, Karel; Shishlov, Alexander; Kokshenev, Vladimir; Ratakhin, Nicolai; Kovalchuk, Boris; Labetsky, Aleksey; Kurmaev, Nikolay; Fursov, Fedor

    2011-10-01

    Deuterium gas-puff experiments have been carried out on the GIT-12 generator at the High Current Electronics Institute in Tomsk. During the initial experiment in May 2011, we used mainly double shell gas puffs with the outer and inner diameter of 100 and 30 mm, respectively. Single shell and shell-on-solid fill gas puffs were, however, also tested. The linear mass density of deuterium varied between 50 and 80 μg/cm. When a plasma-opening-switch (POS) was used, the current reached the peak of above 2.5 MA within 300 ns. The peak neutron yield from D(d,n)3He reactions exceeded 1011. In all shots, the neutron emission started during the stagnation. At the beginning of the neutron production, there was the correlation between the neutron emission and soft X-rays. Nevertheless, the peak of the neutron emission occurred 50 ns after the soft X-ray peak. At this very moment, hard X-rays above 1 MeV were detected. In the case of POS, > 800 keV widths of side-on neutron spectra implied > 200 keV deuterons moving in the radial direction. Work supported by the MSMT grants LA08024, ME09087, LC528.

  18. Deuterium isotope separation

    International Nuclear Information System (INIS)

    Deuterium-containing molecules are separated and enriched by exposing commercially available ethylene, vinyl chloride, 1,2-dichloroethane or propylene to the radiation of tuned infrared lasers to selectively decompose these compounds into enriched molecular products containing deuterium atoms. The deuterium containing molecules can be easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. (author)

  19. Addition of oxygen in the inlet of recombiner unit in moderator cover gas system to facilitate recombination of deuterium and oxygen to bring deuterium concentration in safe limits

    International Nuclear Information System (INIS)

    In moderator system of PHWR, radiolytic decomposition of Heavy Water takes place in the Calandria and D2 and O2 are formed. Since the mixture of D2 and O2 is explosive in nature, there is a limit and various action levels for concentration of Oxygen and deuterium in moderator cover gas. The maximum percentage limit of deuterium is 4% v/v in presence of Oxygen present in stoichiometric ratio. In March -2013, the deuterium concentration in moderator cover gas of RAPS-2 increased to 3.0 % v/v and the oxygen concentration was only 0.93% v/v which was much less than the stoichiometric value (1.5% v/v). So it was decided to add oxygen in the inlet of recombiner unit of moderator cover gas system. As in year 1999 there was a fire incident in Darlington unit -3 due to combustion of EDPM which was used as seat material in the isolating valve in the inlet of oxygen pressure regulating valve. EDPM has low ignition temp. So Oxygen addition was not practiced in any other reactors. Oxygen addition was carried out in RAPS-2 with all precaution and with proper planning. Initially oxygen was added with very slow rate of 1 SCFH (Standard Cubic Feet per Hour) intermittently and the process was repeated to see any harmful effect. After qualifying the procedure, oxygen addition was done for 20 hrs at the rate of 2.5 SCFH and D2 concentration came down to 1.95 % v/v. This paper will consists of radiolytic decomposition of D2O, the qualification plan for O2 addition, the data of moderator cover gas and moderator system parameters before, during and after Oxygen addition. (author)

  20. Recovery of deuterium from argon carrier gas by ZrNi modified with electroless Pd coating

    International Nuclear Information System (INIS)

    The effectiveness of Pd-coating on ZrNi against impurity gas exposure was examined. X-ray diffraction profiles revealed that the surfaces of plate and grain samples are readily covered with Pd by electroless plating. Mutual diffusion between the Pd-overlayer and the ZrNi substrate and PdZr formation took place by vacuum heating above 973 K. Deuterium recovery (DR) in a flowing argon carrier gas containing 5 ppm of impurity gases was examined using packed columns of bare ZrNi and Pd/ZrNi grains. Results indicate that the Pd-coating successfully extends the life time of ZrNi against impurity gases at low temperature below 473 K. Furthermore, no noticeable reduction in DR was found in Pd/ZrNi, whereas bare ZrNi loss its activity at 10 ks at 573 K. (author)

  1. Deuterium gas puff Z-pinch at currents of 2 to 3 mega-ampere

    Science.gov (United States)

    Klir, D.; Shishlov, A. V.; Kubes, P.; Rezac, K.; Fursov, F. I.; Kokshenev, V. A.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.

    2012-03-01

    Deuterium gas-puff experiments have been carried out on the GIT-12 generator at the Institute of High Current Electronics in Tomsk. The emphasis was put on the study of plasma dynamics and neutron production in double shell gas puffs. A linear mass density of deuterium (D2) varied between 50 and 85 μg/cm. Somewhat problematic was a spread of the D2 gas at a large diameter in the central anode-cathode region. The generator operated in two regimes, with and without a plasma opening switch (POS). When the POS was used, a current reached a peak of 2.7 MA with a 200 ns rise time. Without the POS, a current rise time approached 1500 ns. The influence of different current rise times on neutron production was researched. Obtained results were important for comparison of fast deuterium Z-pinches with plasma foci. Average DD neutron yields with and without the POS were about 1011. The neutron yield seems to be dependent on a peak voltage at the Z-pinch load. In all shots, the neutron emission started during stagnation. At the beginning of the neutron production, the neutron emission correlated with soft x-rays and a significant fraction of neutrons could be explained by the thermonuclear mechanism. Nevertheless, a peak of the neutron emission occurred 40 ns after a soft x-ray peak. At this very moment, hard x-rays above 1 MeV were detected and a rapid expansion with a velocity of 3×105 m/s was observed. In the case of the POS, 1 MeV widths of radial neutron spectra implied that there are deuterons with the energy above 200 keV moving in the radial direction. On the basis of D2 gas puff experiments in the 0.3-17 MA region, the neutron yield dependence on a current as Y∝I3.0±0.2 was proposed.

  2. Spectral Characteristics of Deuterium-, Helium- and Gas-Mixture-Discharges within PF-1000 Facility

    International Nuclear Information System (INIS)

    The paper reports on spectroscopic studies of high-current plasma discharges performed at different gas fillings within the large PF-1000 facility. To study visible radiation (VR) the use was made of a MECHELLE registered 900-spectrometer equipped with the CCD readout. The observations of a PF pinch column were performed at an angle of about 65 deg. to the z-axis, and the viewing field was at a distance of 40-50 mm from the electrode ends. Optical measurements were carried out at 0.5-μs exposition synchronized with a chosen period of the investigated discharge. Differences in the optical spectra, recorded at various deuterium-helium mixtures, were analyzed. Intensities of HeI lines were computed for an assumed electron temperature and compared with the experiment. Estimated plasma concentration in pure-deuterium discharges amounted to 8x1018 cm-3, while that in pure helium shots was (4-7)x1017 cm-3 only. Estimates of the electron temperature, from the ratio of intensities of the chosen spectral lines and the continuum, gave values ranging from 5 eV to 50 eV. The paper presents also some spectra from 'weak shots', which show distinct impurity lines caused by different reasons

  3. The HERMES Polarized Hydrogen and Deuterium Gas Target in the HERA Electron Storage Ring

    CERN Document Server

    Airapetian, A; Akopov, Z; Amarian, M; Ammosov, V V; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Baturin, V; Baumgarten, C; Beckmann, M; Belostotskii, S; Bernreuther, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Bouwhuis, M; Brack, J; Brüll, A; Bryzgalov, V V; Capitani, G P; Chiang, H C; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; De Leo, R; De Nardo, L; De Sanctis, E; Devitsin, E G; Di Nezza, P; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G M; Ellinghaus, F; Elschenbroich, U; Ely, J; Fabbri, R; Fantoni, A; Feshchenko, A; Felawka, L; Fox, B; Franz, J; Frullani, S; Gärber, Y; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Garutti, E; Gaskell, D; Gavrilov, G E; Karibian, V; Graw, G; Grebenyuk, O; Greeniaus, L G; Hafidi, K; Hartig, M; Hasch, D; Heesbeen, D; Henoch, M; Hertenberger, R; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Kinney, E; Kiselev, A; Königsmann, K C; Kopytin, M; Korotkov, V A; Kozlov, V; Krauss, B; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Laziev, A; Lenisa, P; Liebing, P; Lindemann, T; Lipka, K; Lorenzon, W; Lü, J; Maiheu, B; Makins, N C R; Marianski, B; Marukyan, H O; Masoli, F; Mexner, V; Meyners, N; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Nass, A; Negodaev, M A; Nowak, Wolf-Dieter; Oganessyan, K; Ohsuga, H; Orlandi, G; Pickert, N; Potashov, S Yu; Potterveld, D H; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Ryckbosch, D; Salomatin, Yu I; Sanjiev, I; Savin, I; Scarlett, C; Schäfer, A; Schill, C; Schnell, G; Schüler, K P; Schwind, A; Seele, J; Seidl, R; Seitz, B; Shanidze, R G; Shearer, C; Shibata, T A; Shutov, V B; Simani, M C; Sinram, K; Stancari, M D; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stösslein, U; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Tkabladze, A V; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Vetterli, Martin C; Vikhrov, V; Vincter, M G; Visser, J; Vogel, C; Vogt, M; Volmer, J; Weiskopf, C; Wendland, J; Wilbert, J; Ybeles-Smit, G V; Yen, S; Zihlmann, B; Zohrabyan, H G; Zupranski, P

    2004-01-01

    The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in use since 1996 with the polarized electron beam of HERA at DESY to study the spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam Source are injected into a storage cell internal to the HERA electron ring. Atoms diffusing from the center of the storage cell into a side tube are analyzed to determine the atomic fraction and the atomic polarizations. The atoms have a nuclear polarization, the axis of which is defined by an external magnetic holding field. The holding field was longitudinal during 1996-2000, and was changed to transverse in 2001. The design of the target is described, the method for analyzing the target polarization is outlined, and the performance of the target in the various running periods is presented.

  4. Development of a hydrogen and deuterium polarized gas target for application in storage rings

    International Nuclear Information System (INIS)

    Polarized gas targets of atomic hydrogen and deuterium have significant advantages over conventional polarized targets, e.g. chemical and isotopic purity, large polarization including deuteron tensor polarization, absence of strong magnetic fields, rapid polarization reversal. While in principle the beam of polarized atoms from an atomic beam source (Stern-Gerlach spin separation) can be used as a polarized target, the target thickness achieved is too small for most applications. We propose to increase the target thickness by injecting the polarized atoms into a storage cell. Provided the atoms survive several hundred wall collisions without losing their polarization, it will be possible to achieve a target thickness of 1013 to 1014 atoms/cm2 by injection of polarized atoms from an atomic-beam source into suitable cells. Such targets are very attractive as internal targets in storage rings

  5. Gas-phase hydrogen/deuterium exchange in a travelling wave ion guide for the examination of protein conformations

    OpenAIRE

    Rand, Kasper D.; Pringle, Steven D.; Murphy, James P.; Fadgen, Keith E.; Brown, Jeff; Engen, John R.

    2009-01-01

    Accumulating evidence suggests that solution-phase conformations of small globular proteins and large molecular protein assemblies can be preserved for milliseconds after electrospray ionization. Thus, the study of proteins in the gas-phase on this time-scale is highly desirable. Here we demonstrate that a travelling wave ion guide (TWIG) of a Synapt mass spectrometer offers a highly suitable environment for rapid and efficient gas-phase hydrogen/deuterium exchange (HDX). Gaseous ND3 was intr...

  6. Retention of deuterium in damaged low-activation steel Rusfer (EK-181) after gas and plasma exposure

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, A.V. [NRC ‘Kurchatov Institute’, Moscow (Russian Federation); Golubeva, A.V., E-mail: anna-golubeva@yandex.ru [NRC ‘Kurchatov Institute’, Moscow (Russian Federation); Bobyr, N.P.; Khripunov, B.I. [NRC ‘Kurchatov Institute’, Moscow (Russian Federation); Cherkez, D.I., E-mail: cherkez@list.ru [NRC ‘Kurchatov Institute’, Moscow (Russian Federation); Petrov, V.B. [NRC ‘Kurchatov Institute’, Moscow (Russian Federation); Mayer, M.; Ogorodnikova, O.V.; Alimov, V.Kh. [Max-Planck-Institut fürPlasmaphysik, Garching (Germany); Klimov, N.S.; Putrik, A. [SRC RF TRINITI, Troitsk (Russian Federation); Chernov, V.M.; Leontieva-Smirnova, M.V. [A.A. Bochvar Institute of Inorganic Materials, Moscow (Russian Federation); Gasparyan, Yu.M.; Efimov, V.S. [National Research Nuclear University “MEPhI”, Moscow (Russian Federation)

    2014-12-15

    Reduced-activation ferritic–martensitic steels (RAFMS) are advanced structural materials for the construction of future fusion reactors with high fluxes of neutrons, such as DEMO or a Fusion Neutron Source (FNS). In the present work the influence of different damages on deuterium retention in the RAFM Rusfer (Chernov et al., 2007) was investigated. Three different types of damage were applied: (i)irradiation by 20 MeV W{sup 6+} ions to a damage fluence of 0.89 dpa (1.4 × 10{sup 18} ions/m{sup 2}). Tungsten ion irradiation was used as proxy for displacement damage created by neutrons; (ii)heat loads in the QSPA-T facility with 10 pulses of 0.5 MJ/m{sup 2} with a duration of 0.5 ms; (iii)low-temperature hydrogen plasma irradiation in the LENTA facility at 320 and 600 K to a fluence of 10{sup 25} H/m{sup 2}. The hydrogen isotope retention properties of the damaged and undamaged material were investigated by exposure to deuterium gas several weeks after damaging. The deuterium retention was investigated in the temperature range of RT–773 K at pressure 10{sup 4} Pa. Deuterium depth profiles were measured a month after gas exposure by nuclear reaction analysis (NRA) using the D({sup 3}He,p)α nuclear reaction. Deuterium retention in damaged and undamaged Rusfer in the temperature range of 300–600 K has a maximum at 500 K for all types of damage investigated. The typical value of deuterium concentration in the bulk is 10{sup −3} at.%. Peculiarities of D retention in damaged samples are discussed.

  7. Long-Implosion-Time Z-pinch Experiments with Deuterium Gas-Puffs on the GIT-12 Generator

    Science.gov (United States)

    Klir, D.; Kubes, P.; Rezac, K.; Cikhardt, J.; Kravarik, J.; Shishlov, A.; Labetsky, A.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Ratakhin, N.

    2012-10-01

    Experiments with deuterium triple shell gas-puffs have been carried out on the GIT-12 generator at the IHCE in Tomsk. Outer, middle, and inner nozzle diameters were 160 mm, 80 mm and 30 mm, respectively. The influence of the mass of deuterium shells on neutron emission times, neutron yields and neutron spectra was studied. The linear mass density of deuterium varied between 50 and 270 μg/cm. Gas puffs imploded onto the axis before the peak of a generator current at 700-1100 ns. The first neutron peak occurred during the stagnation. Most of the neutrons were emitted during the second neutron pulse after the development of instabilities. In lower mass gas puffs, neutron energies of up to 4.4 MeV gave the evidence of 1 MeV deuterons. The peak neutron yield from D(d,n)^3He reactions reached 3x10^11 on a current level of 2.5 MA. Secondary DT neutrons were measured by BDS-10000 bubble detectors. An average neutron yield ratio Y>10 MeV/Y2.5 MeV exceeded (6±3)x10-4. Ne-Ne-D2 and Ne-D2-D2 gas puffs produced 3 times lower neutron yields but the first neutron pulse during the stagnation was nearly the same as with D2-D2-D2 gas puffs.

  8. Deuterium high pressure target

    International Nuclear Information System (INIS)

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  9. Deuterium High Pressure Target

    CERN Document Server

    Perevozchikov, V; Vinogradov, Yu I; Vikharev, M D; Ganchuk, N S; Golubkov, A N; Grishenchkin, S K; Demin, A M; Demin, D L; Zinov, V G; Kononenko, A A; Lobanov, V N; Malkov, I L; Yukhimchuk, S A

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm^3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system.

  10. Diagnostics of deuterium gas-puff z-pinch experiments on the GIT-12 generator

    Science.gov (United States)

    Cikhardt, J.; Klir, D.; Rezac, K.; Kubes, P.; Kravarik, J.; Batobolotova, B.; Sila, O.; Turek, K.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Chedizov, R.; Ratakhin, N.; Varlachev, V.; Garapatsky, A.; Dudkin, G.; Padalko, V.; GIT-12 Team

    2014-10-01

    Z-pinch experiments with a deuterium gas-puff and an outer plasma shell generated by plasma guns were carried out on the GIT-12 generator at the IHCE in Tomsk. Using this novel configuration of the load, the neutron yields from the DD reaction were significantly increased from 2×1011 up to 3×1012 neutrons per shot at the current level of about 3 MA. In addition to recent experiments, the threshold activation detectors were used in order to get the information about the energy spectrum of the generated neutrons. The copper, indium, and lead samples were irradiated by the pulse of the neutrons generated during the experimental shot. The decay radiation of the products from the reactions 63Cu(n,2n)62Cu, 115In(n, γ) 116 mIn and 206Pb (n,3n)204mPb was observed using gamma spectrometer. According to the used neutron ToF scintillation detectors, the energy of neutrons reaches up to 20 MeV. The work was supported by the MSMT of the Czech Republic research Programs No. ME090871, No. LG13029, by the GACR Grant No. P205/12/0454, Grant CRA IAEA No. 17088 and RFBR research Project No. 13-08-00479-a.

  11. Efficient generation of fast neutrons by magnetized deuterons in an optimized deuterium gas-puff z-pinch

    Czech Academy of Sciences Publication Activity Database

    Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubeš, P.; Labetsky, A. Yu.; Řezáč, K.; Cherdizov, R. K.; Cikhardt, J.; Cikhardtová, B.; Dudkin, G. N.; Fursov, F. I.; Garapatsky, A. A.; Kovalchuk, B. M.; Kravařík, J.; Kurmaev, N. E.; Orčíková, Hana; Padalko, V. N.; Ratakhin, N. A.; Šíla, O.; Turek, Karel; Varlachev, V. A.

    2015-01-01

    Roč. 57, č. 4 (2015), 044005. ISSN 0741-3335 R&D Projects: GA ČR GAP205/12/0454; GA MŠk(CZ) LD14089; GA MŠk(CZ) LG13029 Grant ostatní: GA MŠk(CZ) LH13283 Institutional support: RVO:61389005 Keywords : z-pinch * gas puff * deuterium * fast neutrons * plasma guns Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 2.186, year: 2014

  12. Experimental Results from Plasma Shell on Deuterium Gas-puff Z-pinch on the Current Level of 3 MA

    Science.gov (United States)

    Rezac, K.; Klir, D.; Kubes, P.; Kravarik, J.; Shishlov, A.; Labetsky, A.; Kokshenev, V.; Ratakhin, N.; GIT-12 Team

    2013-10-01

    The experiments with a plasma shell on deuterium gas-puff Z-pinch were carried out on the GIT-12 generator at IHCE in Tomsk. We diagnosed Z-pinch shots with deuterium linear mass of about 100 μg/cm. The outer shell of the load was formed by 48 plasma guns positioned on diameter of 350 mm, the diameter of the nozzle producing deuterium inner shell gas-puff was 80 mm. Results obtained from X-ray and neutron diagnostics, especially neutron time-of-flight signals, where 15 MeV neutrons (in radial direction) and 22 MeV neutrons (in axial direction) were registered, are presented. Obtained implosion velocity of the gas-puff had the value of 4 . 5 ×107 cm/s, neutron yield from D(d,n)3He reaction was in order of 1012 neutrons/shot on a current level of about 2.7 MA. The time correlations of the TOF diagnostics with other diagnostics such as electrical characteristics, an MCP frames, and a visible streak camera are also presented. Work supported by MEYS CR research programs No. ME090871, No. LG13029, by GACR grant No. P205/12/0454, grant CRA IAEA No. 17088 and RFBR research project No. 13-08-00479-a.

  13. Compact large-aperture Fabry-Perot interferometer modules for gas spectroscopy at mid-IR

    Science.gov (United States)

    Kantojärvi, Uula; Varpula, Aapo; Antila, Tapani; Holmlund, Christer; Mäkynen, Jussi; Näsilä, Antti; Mannila, Rami; Rissanen, Anna; Antila, Jarkko; Disch, Rolf J.; Waldmann, Torsten A.

    2014-03-01

    VTT has developed Fabry-Pérot Interferometers (FPI) for visible and infrared wavelengths since 90's. Here we present two new platforms for mid-infrared gas spectroscopy having a large optical aperture to provide high optical throughput but still enabling miniaturized instrument size. First platform is a tunable filter that replaces a traditional filter wheel, which operates between wavelengths of 4-5 um. Second platform is for correlation spectroscopy where the interferometer provides a comb-like transmission pattern mimicking absorption of diatomic molecules at the wavelength range of 4.7-4.8 um. The Bragg mirrors have 2-4 thin layers of polysilicon and silicon oxide.

  14. Characterization of neutron emission from mega-ampere deuterium gas puff Z-pinch at microsecond implosion times

    Science.gov (United States)

    Klir, D.; Shishlov, A. V.; Kokshenev, V. A.; Kubes, P.; Labetsky, A. Yu; Rezac, K.; Cikhardt, J.; Fursov, F. I.; Kovalchuk, B. M.; Kravarik, J.; Kurmaev, N. E.; Ratakhin, N. A.; Sila, O.; Stodulka, J.

    2013-08-01

    Experiments with deuterium (D2) triple shell gas puffs were carried out on the GIT-12 generator at a 3 MA current level and microsecond implosion times. The outer, middle and inner nozzle diameters were 160 mm, 80 mm and 30 mm, respectively. The influence of the mass of deuterium shells on neutron emission times, neutron yields and neutron energy spectra was studied. The injected linear mass of deuterium varied between 50 and 255 µg cm-1. Gas puffs imploded onto the axis before the peak of generator current at 700-1100 ns. Most of the neutrons were emitted during the second neutron pulse after the development of instabilities. Despite higher currents, heavier gas puffs produced lower neutron yields. Optimal mass and a short time delay between the valve opening and the generator triggering were more important than the better coincidence of stagnation with peak current. The peak neutron yield from D(d, n)3He reactions reached 3 × 1011 at 2.8 MA current, 90 µg cm-1 injected linear mass and 37 mm anode-cathode gap. In the case of lower mass shots, a large number of 10 MeV neutrons were produced either by secondary DT reactions or by DD reactions of deuterons with energies above 7 MeV. The average neutron yield ratio Y>10 MeV/Y2.5 MeV reached (6 ± 3) × 10-4. Such a result can be explained by a power law distribution for deuterons as \\rmd N_d/\\rmd E_d\\propto E_d^{-3} . The optimization of a D2 gas puff Z-pinch and similarities to a plasma focus and its drive parameter are described.

  15. Deuterium Exchange in Ethyl Acetoacetate: An Undergraduate GC-MS [Gas Chromatography-Mass Spectroscopy] Experiment

    Science.gov (United States)

    Heinson, C. D.; Williams, J. M.; Tinnerman, W. N.; Malloy, T. B.

    2005-01-01

    The role of ethanol O-d in nullifying the deuterolysis may be demonstrated by determining that transesterification of methyl acetoacetate of the ethyl ester occurs as well as deuterium exchange of the five acetoacetate hydrogens. The significant acidity of the methylene protons in the acetoacetate group, the efficacy of base catalysis, the role of…

  16. Applications of the water--gas shift reaction. II. Catalytic exchange of deuterium for hydrogen at saturated carbon

    International Nuclear Information System (INIS)

    Previous studies on the homogeneous catalysis of the water-gas shift reaction by metal complexes of groups 6 and 8 had been carried out using aqueous alcoholic solutions of group 8 metal carbonyl complexes made basic with KOH. Substitution of triethylamine (Et3N) for KOH as base and alcohol for solvent led to the discovery that Et3N in the presence of D2O, CO, and Rh6(CO)16 at 1500C undergoes an unusual catalytic exchange of deuterium for hydrogen. A suggested mechanism for this reaction is given and includes activation of hydrogen at a saturated carbon

  17. Tritium analysis in deuterium gas and deuterated metals of the IVb group

    International Nuclear Information System (INIS)

    In the study of the possibility of D-D nuclear fusion reaction in metallic lattices, tritium detection is one of the ways to demonstrate that such a reaction has taken place. In the tests based on heavy water electrolysis tritium production has been ascertained. It seemed worthwhile to look if, also in the process of metals deuteration, tritium is being produced. In order to detect a possible production it is necessary to analyze both the deuterium used for the operation and the deuterated metals. A system based on the oxidation of deuterium and tritium to water, trapping in a cold trap and finally counting in a scintillation spectrometer has been set up. The possible source of error are discussed. 2 tabs., 3 figs., 13 refs

  18. Extreme methane deuterium, nitrogen and helium enrichment in natural gas from the Homorod seep (Romania)

    OpenAIRE

    Etiope, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Baciu, C.; Babes-Bolyai University, Faculty of Environmental Sciences, Cluj-Napoca, Romania; Schoell, M.; GasConsult International Inc., Berkeley, USA

    2011-01-01

    Methane (CH4) in terrestrial environments, whether microbial, thermogenic, or abiogenic, exhibits a large variance in C and H stable isotope ratios due to primary processes of formation. Isotopic variability can be broadened through secondary, post-genetic processes, such as mixing and isotopic fractionation by oxidation. The highest and lowest 13C and 2H (or D, deuterium) concentrations in CH4 found in various geologic environments to date, are defined as “natural” terrestrial extremes. W...

  19. Efficient Neutron Production from a Novel Configuration of Deuterium Gas-Puff Z-Pinch

    Czech Academy of Sciences Publication Activity Database

    Klir, D.; Kubeš, P.; Řezáč, K.; Cikhardt, J.; Kravarik, J.; Šíla, O.; Shishlov, A. V.; Kovalchuk, B. M.; Ratakhin, N. A.; Kokshenev, V. A.; Labetsky, A. Yu.; Cherdizov, R. K.; Fursov, F. I.; Kurmaev, N. E.; Dudkin, G. N.; Nechaev, B. A.; Padalko, V. N.; Orčíková, Hana; Turek, Karel

    2014-01-01

    Roč. 112, č. 9 (2014), 095001. ISSN 0031-9007 R&D Projects: GA ČR GAP205/12/0454; GA MŠk(CZ) LG13029 Grant ostatní: GA MŠk(CZ) LH13283 Institutional support: RVO:61389005 Keywords : deuterium * neutron yield * neutron production Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 7.512, year: 2014

  20. DEVELOPMENT OF A HYDROGEN AND DEUTERIUM POLARIZED GAS TARGET FOR APPLICATION IN STORAGE RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Willy Haeberli

    2009-06-18

    The exploration of spin degrees of freedom in nuclear and high-energy interactions requires the use of spin-polarized projectiles and/or spin-polarized targets. During the last two decades, the use of external beams from cyclotrons has to a large extent been supplanted by use of circulating beams stored in storage rings. In these experiments, the circulating particles pass millions of times through targets internal to the ring. Thus the targets need to be very thin to avoid beam loss by scattering out of the acceptance aperture of the ring.

  1. Acceleration of Hydrogen Ions up to 30 MeV and Generation of 3 × 1012 Neutrons in Megaampere Deuterium Gas-Puff Z-Pinch

    Science.gov (United States)

    Klir, D.; Cikhardt, J.; Kravarik, J.; Kubes, P.; Rezac, K.; Sila, O.; Shishlov, A.; Cherdizov, R.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Labetsky, A.; Ratakhin, N.; Orcikova, H.; Turek, K.

    2013-10-01

    Fusion neutrons were produced with a deuterium gas-puff z-pinch on the GIT-12 generator at the Institute of High Current Electronics in Tomsk. The peak neutron yield from DD reactions reached Yn = (2 . 9 +/- 0 . 3) ×1012 at 100 μg/cm linear mass density of deuterium, 700 ns implosion time and 2.7 MA current. Such a neutron yield means that the scaling law of deuterium z-pinches Yn ~I4 was extended to 3 MA currents. The further increase of neutron yields up to (3 . 7 +/- 0 . 4) ×1012 was achieved by placing a deuterated polyethylene catcher onto the axis. Maximum neutron energies of 15 and 22 MeV were observed by radial and axial nToF detectors, respectively. A stack of CR-39 track detectors showed up to 40 MeV deuterons (or 30 MeV protons) on the z-pinch axis. Since the energy input into plasmas was 70 kJ, the number of DD neutrons per one joule of stored plasma energy exceeded the value of 5 ×107 . This value implies that deuterium gas-puff z-pinches belong to the most efficient plasma-based sources of DD neutrons. This work was partially supported by the GACR grant No. P205/12/0454 and by the RFBR research project No. 13-08-00479-a.

  2. The new technology on creation of multiatmispheric wide aperture high power gas lasers

    International Nuclear Information System (INIS)

    Review is presented about the series of works on creation of 10-atmospheric wide aperture (with active volume 5x5x55 cm3 preionized by x-ray source) CO2-amplifier which was used as main unit of picosecond laser system Picasso [1-4]. The success was reached on putting in operation of this laser system with out put laser energy 22 J and fulfilling of the first experiments on hot plasma ignition by the train of 100 picosecond laser pulses. The new phenomenon was discovered: penetration through metallic shields by the fast (less than 1 nanosecond) magnetic field pulses generated in hot plasma in opposite to long magnetic field pulses which were unable to do this. Author is analyzing the main technologic problem on creation of such multiatmospheric wide aperture (MAWA) lasers and amplifiers – the necessity to create the large complicated window (10x70 cm2 size in case of Picasso facility) on the glass-plastic cylindrical body of the amplifier. This window consists of the pair of metallic flanges with ∼ 300 holes (of 10 mm diameter) in every one of them and 50 µm thick aluminum foil between flanges for x-ray entrance into laser volume for its preionization. Such a system would to provide high flux of x-rays and both evacuation of the amplifier’s chamber up to 0.1 torr and its safety operation at excess pressures not less than 10 atm. However, during the all time of the system’s operation the problem was existed on amplifier’s volume pressurization and aluminum foil’s safeness. There for it was impossible to increase further the gas pressure in amplifier. Author arrived to an idea which can allow the excluding fully the use of such large complicated window system with a foil on MAWA amplifier. According calculations the application of the new proposed approach can provide at least 10-fold increase of the x-ray flux for preionization of laser active volume, - it has the principal important meaning for reaching of stabile volume self sustained discharge for

  3. Surface modification and deuterium retention in reduced activation ferritic martensitic steels exposed to low-energy, high flux D plasma and D2 gas

    International Nuclear Information System (INIS)

    Samples prepared from steels F82H and EUROFER97 were irradiated with 20 MeV W ions at 300 K to 0.54 displacements per atom at the damage peak. Damaged and undamaged samples were exposed at elevated temperatures both to deuterium plasma at ion energies of 60 and 200 eV to a fluence of ≈1026 D m−2 and to D2 gas at a pressure of 100 kPa. The surface modification after plasma exposure was examined by scanning electron microscopy and Rutherford backscattering spectroscopy. Deuterium depth profiles were determined by the D(3He, p)4He nuclear reaction. In damaged steels loaded with deuterium, deuterium decorates the damage profile and the D concentration decreases with increasing temperature. After exposure of the F82H steel to the D plasma W-enriched near-surface layers are formed. The effective concentration of W in the near-surface steel layer depends on plasma exposure conditions. (paper)

  4. Acceleration of Deuterons to Multi-MeV Energies in Deuterium Gas-Puff Z-Pinch

    Science.gov (United States)

    Klir, D.; Cikhardt, J.; Cikhardtova, B.; Kravarik, J.; Kubes, P.; Rezac, K.; Sila, O.; Shishlov, A.; Cherdizov, R.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Labetsky, A.; Ratakhin, N.; Krasa, J.; Turek, K.

    2015-11-01

    A novel configuration of a deuterium gas-puff z-pinch has been used to generate a short (approx. 20 ns) pulse of multi-MeV ions and neutrons. Even though ion acceleration in z-pinches has not been researched to such an extent as in laser-based sources, obtained results show that z-pinches can reach values comparable to those of state-of-the-art lasers. On the 3 MA GIT-12 generator, the peak neutron yield was 3.6x1012. When a neutron-producing sample was placed onto the axis below a cathode mesh, the neutron yield was increased up to 1013. The emission time of 20 ns implied the neutron production rate of 5x1020 n/s. Neutron energies reached the maximum value of 33 MeV. The comprehensive set of ion diagnostics provided unique information about ion acceleration mechanism. The ion emission was highly anisotropic. Deuterons were trapped in the radial direction whereas a lot of fast ions escaped the z-pinch along the axis. On the axis, the total number of >1 MeV and >25 MeV deuterons was 1016 and 5x1012, respectively. Utilizing these ions offers a real possibility of various applications including the production of short-lived isotopes or fast neutron radiography. This work was supported by the MSMT grants LH13283, LD14089.

  5. Deuterium Gas-Puff Z-pinch as a Source of Fast Ions Producing Intensive Pulse of Neutrons

    Science.gov (United States)

    Rezac, K.; Cikhardt, J.; Cikhardtova, B.; Klir, D.; Kravarik, J.; Kubes, P.; Sila, O.; Shishlov, A.; Cherdizov, R.; Fursov, F.; Kokshenev, V.; Kovalchuk, B.; Kurmaev, N.; Labetsky, A.; Ratakhin, N.; Turek, K.

    2015-11-01

    A deuterium gas-puff with outer plasma shell has been examined on GIT-12 generator (on the current level of 3 MA) since 2013. Such a configuration caused more stable implosion at final stage of z-pinch. The consequence of this was a production of intensive pulses of fast ions. During last 4 campaigns in 2013-2015, fast ions were examined by several in-chamber diagnostics such as: stack detector (ion energy), pinhole camera (location of ion source), multi-pinhole camera (asymmetry and anisotropy of ion emission), and ion beam detector (dynamics of ion pulses). A CR-39 track detectors and also GAFCHROMIC HD-V2 films from these diagnostics will be presented. On the basis of obtained results, the solid sample for increasing of neutron yield up to 1e13 could be placed below the cathode mesh. Except of neutron yield, other properties such as: neutron energies (up to 33 MeV), neutron emission time (about 20 ns), and emission anisotropy of neutrons were measured. Such a short and intensive neutron pulse provides various applications. This work was supported by the MSMT project LH13283.

  6. Neutron production in deuterium gas-puff z-pinch with outer plasma shell at current of 3 MA

    Science.gov (United States)

    Cikhardt, J.; Klir, D.; Rezac, K.; Cikhardtova, B.; Kravarik, J.; Kubes, P.; Sila, O.; Shishlov, A. V.; Cherdizov, R. K.; Frusov, F. I.; Kokshenev, V. A.; Kurmaev, N. E.; Labetsky, A. Yu.; Ratakhin, N. A.; Dudkin, G. N.; Garapatsky, A. A.; Padalko, V. N.; Varlachev, V. A.; Turek, K.; Krasa, J.

    2015-11-01

    Z-pinch experiments at the current of about 3 MA were carried out on the GIT-12 generator. The outer plasma shell of deuterium gas-puff was generated by the system of 48 plasma guns. This configuration exhibits a high efficiency of the production of DD fusion neutrons with the yield of above 1012 neutrons produced in a single shot with the duration of about 20 ns. The maximum energy of the neutrons produced in this pulse exceeded 30 MeV. The neutron radiation was measured using scintillation TOF detectors, CR-39 nuclear track detectors, bubble detectors BD-PND and BDS-10000 and by several types of nuclear activation detectors. These diagnostic tools were used to measure the anisotropy of neutron fluence and neutron energy spectra. It allows us to estimate the total number of DD neutrons, the contribution of other nuclear reactions, the amount of scattered neutrons, and other parameters of neutron production. This work was supported by the MSMT grants LH13283, LD14089.

  7. Neutron Diagnostics of a Deuterium Gas-Puff Z-pinch on the Level of 3 MA

    Science.gov (United States)

    Rezac, Karel; Klir, Daniel; Kubes, Pavel; Kravarik, Jozef; Shishlov, Alexander; Labetsky, Aleksey; Ratakhin, Nicolai; GIT-12 Team

    2011-10-01

    The diagnostics of a deuterium gas-puff Z-pinch (outer shell with diam. of 100 or 80 mm, inner annular with diam. of 30 mm or solid-fill shell with diam. of 20 mm with linear mass varied in each shell in the range of 25 - 40 μg/cm) is presented. The experiments were carried out on the GIT-12 generator at IHCE in Tomsk (2.5 MJ bank energy, load current of 2.8 MA with the rise time of 250 ns) during the April-May campaign in 2011. Results from the neutron time-of-flight diagnostics including the determination of the neutron production time and reconstructed radial energy spectra are shown. Several methods which provided measurement of the total neutron yield indicated the number of neutrons in order of 1011 per one shot. The time correlations with other diagnostics such as electrical characteristics, soft X-rays, hard X-rays and a visible streak camera are also presented. Work supported by MEYS research programs No. LA08024, No. ME09087, No. LC528, by GACR grants No. 202-08-H057 and grant CRA IAEA No. 14817.

  8. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Tafreshian, Amirmahdi; Valentine, Stephen J.

    2015-07-01

    The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H]4+ ions exhibit two major conformer types with collision cross sections of 418 Å2 and 446 Å2; the [M + 3H]3+ ions also yield two different conformer types having collision cross sections of 340 Å2 and 367 Å2. Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H]3+ ions show faster HDX rate contributions compared with [M + 4H]4+ ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H]4+ ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS).

  9. Deuterium migration in nuclear graphite: consequences for the behavior of tritium in Gas Cooled Reactors and for the decontamination of irradiated graphite waste

    International Nuclear Information System (INIS)

    In France, 23 000 t of irradiated graphite that will be generated by the decommissioning of the first generation Uranium Naturel-Graphite-Gaz (UNGG) nuclear reactors are waiting for a long term management solution. This work focuses on the behavior of tritium, which is one of the main contributors to the radiological inventory of graphite waste after reactor shutdown. In order to anticipate tritium release during dismantling or waste management, it is mandatory to collect data on its migration, location and inventory. Our study is based on the simulation of tritium by implantation of approximately 3 at. % of deuterium up to around 3 μm in a virgin nuclear graphite. This material was then annealed up to 300 h and 1300 C in inert atmosphere, UNGG coolant gas and humid gas, aiming to reproduce thermal conditions close to those encountered in reactor and during waste management operations. The deuterium profiles and spatial distribution were analyzed using the nuclear reaction 2H(3He,p)4He. The main results evidence a thermal release of implanted deuterium occurring essentially through three regimes controlled by the detrapping of atomic deuterium located in superficial or interstitial sites. The extrapolation of our data to tritium suggests that its purely thermal release during reactor operations may have been lower than 30 % and would be located close to the graphite free surfaces. Consequently, most of the tritium inventory after reactor shutdown could be trapped deeply within the irradiated graphite structure. Decontamination of graphite waste should then require temperatures higher than 1300 C, and would be more efficient in dry inert gas than in humid gas. (author)

  10. Deuterium chemistry of dense gas in the vicinity of low-mass and massive star-forming regions

    OpenAIRE

    Awad, Z.; Viti, S.; Bayet, E.; Caselli, P.

    2014-01-01

    The standard interstellar ratio of deuterium to hydrogen (D/H) atoms is $\\sim 1.5 \\times 10^{-5}$. However, the deuterium fractionation is in fact found to be enhanced, to different degrees, in cold, dark cores, hot cores around massive star forming regions, lukewarm cores, and warm cores ({\\it hereafter}, hot corinos) around low-mass star forming regions. In this paper, we investigate the overall differences in the deuterium chemistry between hot cores and hot corinos. We have modelled the c...

  11. Enhanced performance of a wide-aperture copper vapour laser with hydrogen additive in neon buffer gas

    Indian Academy of Sciences (India)

    Bijendra Singh; V V Subramaniam; S R Daultabad; Ashim Chakraboty

    2010-11-01

    A wide-aperture copper vapour laser was demonstrated at ∼ 10 kHz rep-rate with hydrogen additive in its buffer gas. Maximum power in excess of ∼ 50 W (at 10 kHz) was achieved by adding 1.96% hydrogen to the neon buffer gas at 20 mbar total gas pressure. This increase in output power was about 70% as compared to ∼ 30 W achieved with pure neon at 5.5 kHz rep-rate. The 70% enhancement achieved was significantly higher than the maximum reported value of 50% so far in the literature. The enhancement was much higher (about 150%) as compared to its 20 W power at 10 kHz rep-rate using pure neon as the standard CVL operation.

  12. Seismic characterization of a gas hydrate system in the Gulf of Mexico using wide-aperture data

    Energy Technology Data Exchange (ETDEWEB)

    Jaiswal, P.; Zelt, C.A. [Rice Univ., Houston, TX (United States). Dept. of Earth Science; Pecher, I.A. [Institute of Geological and Nuclear Sciences, Lower Hutt (New Zealand)

    2006-04-15

    Gas hydrates were discovered in a mud mound in the lease block Mississippi Canyon 798, Gulf of Mexico, through piston coring. Subsequently, a seismic experiment was carried out to investigate the dynamics behind the hydrate formation. During the experiment, high-resolution multichannel seismic reflection data using a 24-channel, 240 m long streamer and wide-aperture data using six ocean bottom seismometers were collected along five lines. High-reflectivity zones (HRZs) are present in the reflection data along all lines. To better constrain the interpretation of the reflection data, the traveltimes from the multichannel and wide-aperture data sets were jointly inverted to estimate a 2-D P-wave layered velocity model for each line. A minimum-parameter/minimum-structure modelling approach yielded simple models and a comparison of the models at their intersection points shows they are consistent to within {+-}10 m s{sup -1} in velocity and {+-}20 m in depth. In the final P-wave velocity models, the HRZs are associated with a lowering of velocity. In the reflection data, the top of the HRZs show a polarity reversal with respect to the seafloor. Presence of free gas in the HRZs best explains the velocity lowering and polarity reversal. It is speculated that the gas has deeper sources and migrates upwards through conduits formed by salt movement in the vicinity. The upward migrating gas accumulates in the axis of a channel complex and manifests itself as HRZs in the reflection data. The fluids circulating along the conduits push the base of the hydrate stability zone close to the seafloor. From the channel axis, the free gas migrates further upwards and close to the seafloor, and as it comes within the gas hydrate stability zone, it forms hydrates. (author)

  13. Chemical composition and structural phase changes of novel synthesized structure and of Pd sample under γ-quanta irradiation in dense deuterium gas

    International Nuclear Information System (INIS)

    Studies have been carried out into the element composition of Pd and brass with associated materials and of synthesized novel structure (ANNAWIT), placed in dense deuterium gas in a special high-pressure chamber (HPC) under the pressure of 3 kbar and irradiated with γ-quanta of energy up to 8.8 MeV. Using the methods of scanning electron microscopy, microelement chemical analysis and X-ray diffraction, it was determined that in the absence of all HPC-forming materials in the chamber volume and walls, the synthesized structure is largely composed of alumosilicates and Al and Si oxides with high content of Ti compounds as rutile TiO2, Pd1.5D2. Considerable anomalies in the chemical composition were found both on the surface and at large depth in a Pd specimen. The entire Pd surface turned into a structure comprised of Pd clusters, Cu and Zn compounds, with a notable content of Mg, Al, S, Si, K, Ca, Ti, and Fe compounds. Results of evaluative calculations, including computation of the Q-value, are presented for nuclear reactions produced in a saturated with deuterium Pd specimen and dense deuterium gas under the action of γ-quanta, neutrons and protons of energies up to En+Ep ≅ Eγ - ΔW MeV generated by deuteron fission. The obtained results can be explained by 'collective effects' as chain reactions caused by deuteron fission induced by protons (Ep > 3.39 MeV) and neutrons (En > 2.25 MeV), as well as by thermonuclear synthesis of deuterium atoms elastically scattered by protons of energies up to EP γ - ΔW MeV

  14. Nuclear reactions in palladium saturated with deuterium and rhenium in dense deuterium gas under irradiation by γ-quanta of continuous spectrum with boundary 23 MeV energy

    International Nuclear Information System (INIS)

    Elemental composition studies of Pd and Re samples irradiated by γ-quanta in dense deuterium gas of continuous spectrum with the boundary 23 MeV energy were carried out. Significant anomalies in the structure and chemical composition are obtained. Considerable changes are observed at both ends of the Pd and Re wire as blowouts of molten metal with complex element composition, resembling congealed Solar protuberances. The cracky surfaces of the Pd and Re wires were covered with 1-2 m particles predominantly composed of rhenium oxide RexCy. These particles had been crystallized into small hexagonal crystallites near the cracks in the palladium. The rhenium surface was covered by a thick layer with a large carbon concentration. A short description of the phenomenological model of nuclear reactions leading to the observed anomalies is presented

  15. Optimum extracted H- and D- current densities from gas-pressure-limited high-power hydrogen/deuterium tandem ion sources

    International Nuclear Information System (INIS)

    The tandem hydrogen/deuterium ion source is modelled for the purpose of identifying the maximum current densities that can be extracted subject to the gas-pressure constraints proposed for contemporary beam-line systems. Optimum useful extracted current densities are found to be in the range of approximately 7 to 10 mA cm-2. The sensitivity of these current densities is examined subject to uncertainties in the underlying atomic/molecular rate processes; A principal uncertainty remains the quantification of the molecular vibrational distribution following H3+ wall collisions

  16. Low Energy Nuclear Transmutation in Condensed Matter Induced by D2 Gas Permeation Through pd Complexes:. Correlation Between Deuterium Flux and Nuclear Products

    Science.gov (United States)

    Iwamura, Y.; Itoh, T.; Sakano, M.; Sakai, S.; Kuribayashi, S.

    2005-12-01

    Observations of low energy nuclear reactions induced by D2 gas permeation through Pd complexes (Pd/CaO/Pd) were presented at ICCF-91 and in a paper2 published in the Japanese Journal of Applied Physics. When Cs was added on the surface of a Pd complex, Pr emerged on the surface while Cs decreased after the Pd complex was subjected to D2 gas permeation. When Sr was added to the surface, Mo emerged while the Sr decreased after D2 gas permeation. The isotopic composition of the detected Mo was different from the natural abundance. In this paper, recent progress of our research is described. The detected Pr was confirmed by various methods such as TOF-SIMS, XANES, X-ray Fluorescence Spectrometry and ICP-MS. Analysis of the depth profile of Pr indicated that a very thin surface region up to 100 Å was the active transmutation zone. Many experimental results showed that the quantity of Pr was proportional to the deuterium flux through Pd complex. The cross-section of transmutation of Cs into Pr can be roughly estimated at 1 barn if we consider the deuterium flux as an ultra low energy deuteron beam.

  17. Pionic deuterium

    CERN Document Server

    Strauch, Th; Anagnostopoulos, D; Bühler, P; Covita, D S; Gorke, H; Gotta, D; Gruber, A; Hirtl, A; Indelicato, P; Bigot, E -O Le; Nekipelov, M; Santos, J M F dos; Schmid, Ph; Schlesser, S; Simons, L M; Trassinelli, M; Veloso, J F C A; Zmeskal, J

    2010-01-01

    The strong interaction shift $\\epsilon$ and broadening {\\Gamma} in pionic deuterium have been determined in a high statistics study of the {\\pi}D(3p - 1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium shift will provide constraints for the pion-nucleon isospin scattering lengths extracted from measurements of shift and broadening in pionic hydrogen. The hadronic broadening is related to pion absorption and production at threshold. The results are \\epsilon = (-2356 {\\pm} 31)meV (repulsive) and {\\Gamma}1s = (1171+23/-49) meV yielding for the complex {\\pi}D scattering length a = [-(24.99 {\\pm} 0.33) + i (6.22+0.12/-0.26 )]x10-3/m{\\pi}. From the imaginary part, the threshold parameter for pion production is obtained to be {\\alpha} = (251 +5/-11) {\\mu}b. This allows, in addition, and by using results from pion absorption in 3He at threshold, the determination of the effective couplings g0 and g1 for s-wave pion absorption on isoscalar and isovector NN pairs.

  18. Pionic deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Strauch, T.; Gotta, D.; Nekipelov, M. [Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany); Amaro, F.D.; Santos, J.M.F. dos [Coimbra University, Department of Physics, Coimbra (Portugal); Anagnostopoulos, D.F. [University of Ioannina, Department of Materials Science and Engineering, Ioannina (Greece); Buehler, P.; Gruber, A.; Hirtl, A.; Schmid, P.; Zmeskal, J. [Austrian Academy of Sciences, Stefan Meyer Institut for Subatomic Physics, Vienna (Austria); Covita, D.S. [Coimbra University, Department of Physics, Coimbra (Portugal); Paul Scherrer Institut, Laboratory for Particle Physics, Villigen (Switzerland); Gorke, H. [Forschungszentrum Juelich GmbH, Zentralinstitut fuer Elektronik, Juelich (Germany); Indelicato, P.; Le Bigot, E.O.; Schlesser, S.; Trassinelli, M. [UPMC-Paris 6, ENS, CNRS, Laboratoire Kastler Brossel, Paris (France); Simons, L.M. [Paul Scherrer Institut, Laboratory for Particle Physics, Villigen (Switzerland); Veloso, J.F.C.A. [Aveiro University, I3N, Department of Physics, Aveiro (Portugal)

    2011-07-15

    The strong-interaction shift {epsilon}{sub 1s}{sup {pi}}{sup D} and broadening {gamma}{sub 1s}{sup {pi}}{sup D} in pionic deuterium have been determined in a high statistics study of the {pi}D(3p-1s) X-ray transition using a high-resolution crystal spectrometer. The pionic deuterium shift will provide constraints for the pion-nucleon isospin scattering lengths extracted from measurements of shift and broadening in pionic hydrogen. The hadronic broadening is related to pion absorption and production at threshold. The results are {epsilon}{sub 1s}{sup {pi}}{sup D}=(-2356 {+-} 31) meV (repulsive) and {gamma}{sub 1s}{sup {pi}}{sup D} meV yielding for the complex {pi}D scattering length a{sub {pi}}{sub D}=[-(24.99 {+-}0.33)+i(6.22{sub -0.26} {sup +0.12}) ]x 10{sup -3} m{sub {pi}}{sup -1}. From the imaginary part, the threshold parameter for pion production is obtained to be {alpha} = (251{sub -11} {sup +5}){mu}b. This allows, in addition, and by using results from pion absorption in {sup 3}He at threshold, the determination of the effective couplings g{sub 0} and g{sub 1} for s-wave pion absorption on isoscalar and isovector NN pairs. (orig.)

  19. Method of deuterium isotope separation using ethylene and ethylene dichloride

    International Nuclear Information System (INIS)

    Compounds enriched in deuterium may be obtained from ethylene, vinyl chloride, 1,2-dichloroethane, or propylene by laser isotope separation. Normal molecules of these organic compounds are exposed to infrared laser radiation of a suitable wavelength. Substantially all of the deuterium-containing molecules exposed to the laser can be selectively dissociated and the deuterium-containing products separated from the starting material and other reaction products. The deuterium-containing molecules can be burned to form water with an enriched deuterium content, or pyrolized to form hydrogen gas enriched in deuterium

  20. Isotope dilution studies: determination of carbon-13, nitrogen-15 and deuterium-enriched compounds using capillary gas chromatography-chemical reaction interface/mass spectrometry

    International Nuclear Information System (INIS)

    In addition to the ability of a capillary gas chromatographic-chemical reaction interface/mass spectrometric technique (CRIMS) to detect the presence of 13C, 15N and 2H (D) it can also quantify the level of the enriched substance. To evaluate linearity and detection limits the authors used phenytoin as an example of an unlabeled substance and added various labeled phenytoin analogs. Atom enrichments of 0.3% were detectable for (2,4,5-13C3) phenytoin and 0.06% for (1,3-15N2)labeled phenytoin, each in the presence of 500 ng of unlabeled phenytoin, respectively. For deuterium, enrichment could not be directly determined. However, 1 ng of (ring D10) phenytoin was determined in the presence of 500 ng of unlabeled diethylated phenytoin. CRIMS was found capable of quantifying 13C-, 15N-and D-enriched substances. (author)

  1. Interaction of a deuterium atomic beam with a palladium membrane

    Energy Technology Data Exchange (ETDEWEB)

    Livshits, A.I.; Metter, I.M.; Samartsev, A.A.

    1976-07-01

    It is suggested that under certain conditions the permeability of a solid membrane of the usual thickness for gases can be comparable to the permeability of an aperture in a thin wall. Experiments are carried out to test this suggestion. A study is made of the penetration of deuterium from a thermal atomic beam with a flux density of 10/sup 11/--10/sup 12/ atoms/cm/sup 2/xsec) through an ''inactive'' palladium membrane (i.e., which is comparatively impenetrable for molecular hydrogen). The probability for the penetration of deuterium atoms in a single collision with the membrane over the temperature range 20--520degreeC is independent of the temperature and is equal to 0.1 (i.e., a value of the same order of magnitude as the sticking probability for hydrogen atoms on metals). It is shown experimentally that the desorption is of second order in the concentration of the desolved gas. It is suggested that each atom which recombines at the membrane is first absorbed and then reaches the opposite boundary.

  2. Effect of deposited tungsten on deuterium accumulation in beryllium in contact with atomic deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Sharapov, V.M.; Gavrilov, L.E. [Institute of Physical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation); Kulikauskas, V.S.

    1998-01-01

    Usually ion or plasma beam is used for the experiment with beryllium which simulates the interaction of plasma with first wall in fusion devices. However, the use of thermal or subthermal atoms of hydrogen isotopes seems to be useful for that purpose. Recently, the authors have studied the deuterium accumulation in beryllium in contact with atomic deuterium. The experimental setup is shown, and is explained. By means of elastic recoil detection (ERD) technique, it was shown that in the exposure to D atoms at 740 K, deuterium is distributed deeply into the bulk, and is accumulated up to higher concentration than the case of the exposure to molecular deuterium. The depth and concentration of deuterium distribution depend on the exposure time, and those data are shown. During the exposure to atomic deuterium, oxide film grew on the side of a sample facing plasma. In order to understand the mechanism of deuterium trapping, the experiment was performed using secondary ion mass spectrometry (SIMS) and residual gas analysis (RGA). The influence that the tungsten deposit from the heated cathode exerted to the deuterium accumulation in beryllium in contact with atomic deuterium was investigated. These results are reported. (K.I.)

  3. Primary deuterium isotope effects in the gas phase reactions of nucleophiles with alkyl halides. Evidence of E2 and SN2 pathways

    International Nuclear Information System (INIS)

    Nucleophilic reactions have been widely studied in the gas phase; nevertheless, there is little known about the competition between substitution (SN2) and elimination (E2) processes in the nucleophilic reactions of simple organic substrates such as alkyl halides. Since both of these mechanisms yield the same ions, they cannot be distinguished by simple mass analysis of the ionic products. In this study, the authors report the use of reaction kinetics and primary deuterium isotope effects to differentiate between elimination and substitution mechanisms for a series of anions reacting with a variety of alkyl halides. The authors have employed a tandem flowing afterglow-selected ion flow tube (FA-SIFT) to measure the reaction rate coefficients of a number of nucleophiles with a series of deuterated alkyl chlorides and bromides chosen to explore a variety of substitution patterns. Isotope effects are expected for E2 reactions where nucleophilic attack occurs at a β-hydrogen but should be minimal for SN2 displacements at carbon. For isotope effects to be evident, the reaction efficiency must be sufficiently below unity so that small differences in the transition state are reflected in the reaction rate coefficients. Consider first the reactions of the oxygen nucleophiles, CF3CH2O- and CF3CF2CH2O-, with the alkyl chlorides. It is evident that the rates generally increase with greater carbon substitution, a pattern clearly more consistent with an E2 rather than an SN2 mechanism

  4. Deuterium Substitution used as a Tool for Investigating Mechanisms of Gas-Phase Free-Radical Reactions

    Science.gov (United States)

    Wine, P. H.; Hynes, A. J.; Nicovich, J. M.

    1997-01-01

    Results are presented and discussed for a number of gas phase free radical reactions where H/D isotope effects provide valuable mechanistic insights. The cases considered are (1) the reactions of OH, NO3, and Cl with atmospheric reduced sulfur compounds, (2) the reactions of OH and OD with CH3CN and CD3CN, and (3) the reactions of alkyl radicals with HBr and DBr.

  5. Quantitative analysis of deuterium in zircaloy using double-pulse laser-induced breakdown spectrometry (LIBS) and helium gas plasma without a sample chamber.

    Science.gov (United States)

    Suyanto, H; Lie, Z S; Niki, H; Kagawa, K; Fukumoto, K; Rinda, Hedwig; Abdulmadjid, S N; Marpaung, A M; Pardede, M; Suliyanti, M M; Hidayah, A N; Jobiliong, E; Lie, T J; Tjia, M O; Kurniawan, K H

    2012-03-01

    A crucial safety measure to be strictly observed in the operation of heavy-water nuclear power plants is the mandatory regular inspection of the concentration of deuterium penetrated into the zircaloy fuel vessels. The existing standard method requires a tedious, destructive, and costly sample preparation process involving the removal of the remaining fuel in the vessel and melting away part of the zircaloy pipe. An alternative method of orthogonal dual-pulse laser-induced breakdown spectrometry (LIBS) is proposed by employing flowing atmospheric helium gas without the use of a sample chamber. The special setup of ps and ns laser systems, operated for the separate ablation of the sample target and the generation of helium gas plasma, respectively, with properly controlled relative timing, has succeeded in producing the desired sharp D I 656.10 nm emission line with effective suppression of the interfering H I 656.28 nm emission by operating the ps ablation laser at very low output energy of 26 mJ and 1 μs ahead of the helium plasma generation. Under this optimal experimental condition, a linear calibration line is attained with practically zero intercept and a 20 μg/g detection limit for D analysis of zircaloy sample while creating a crater only 10 μm in diameter. Therefore, this method promises its potential application for the practical, in situ, and virtually nondestructive quantitative microarea analysis of D, thereby supporting the more-efficient operation and maintenance of heavy-water nuclear power plants. Furthermore, it will also meet the anticipated needs of future nuclear fusion power plants, as well as other important fields of application in the foreseeable future. PMID:22283593

  6. Fine target of deuterium

    International Nuclear Information System (INIS)

    A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 μ gr/cm2 thick is obtained. (Author) 1 refs

  7. Selective detection of carbon-13, nitrogen-15, and deuterium labeled metabolites by capillary gas chromatography-chemical reaction interface/mass spectrometry

    International Nuclear Information System (INIS)

    We have applied a new chemical reaction interface/mass spectrometer technique (CRIMS) to the selective detection of 13C-, 15N-, and 2H-labeled phenytoin and its metabolites in urine following separation by capillary gas chromatography. The microwave-powered chemical reaction interface converts materials from their original forms into small molecules whose mass spectra serve to identify and quantify the nuclides that make up each analyte. The presence of each element is followed by monitoring the isotopic variants of CO2, NO, or H2 that are produced by the chemical reaction interface. Chromatograms showing only enriched 13C and 15N were produced by subtracting the abundance of naturally occurring isotopes from the observed M + 1 signal. A selective chromatogram of 2H (D) was obtained by measuring HD at m/z 3.0219 with a resolution of 2000. Metabolites representing less than 1.5% of the total labeled compounds could be identified in the chromatogram. Detection limits from urine of 380 pg/mL of a 15N-labeled metabolite, 7 ng/mL of a 13C-labeled metabolite, and 16 ng/mL of a deuterium labeled metabolite were determined at a signal to noise ratio of 2. Depending on the isotope examined, a linear dynamic range of 250-1000 was observed using CRIMS. To identify many of these labeled peaks (metabolites), the chromatographic analysis was repeated with the chemical reaction interface turned off and mass spectra obtained at the retention times found in the CRIMS experiment. CRIMS is a new analytical method that appears to be particularly useful for metabolism studies

  8. Changes of surface structure and elemental composition of components of DHPC inner surfaces, irradiated with 10-MeV γ quanta in dense deuterium gas

    International Nuclear Information System (INIS)

    This work is a continuation and addition to [1], which presented results on the studies of surface and elemental compositions of Pd rod and brass screw for collection of nuclear and chemical reaction products in a deuterium high-pressure chamber (DHPC) under irradiation with γ quanta with an energy of 10 MeV during 18 h at the electron accelerator MT-25 at the beam current 11-13 μA. The DHPC was filled with 1.2 kbar molecular deuterium, in which a Pd rod saturated with deuterium was loaded. After irradiation the elemental compositions of other surfaces of all DHPC elements, which were inside the DHPC in dense deuterium, were studied using electron scanning microscope and X-ray microprobe analysis. It was established that all surfaces including the surface of a high-purity palladium rod (99.995%) were covered with partly homogeneous layer or large microparticles of lead. Also, such light elements as 6C, 8O, 11Na, 12Mg, 13Al, 14Si, 22Ti, 25Mn, 26Fe, 29Cu, 30Zn and heavy metals as 47Ag, 73Ta, 74W, 78Pt, 79Au and 82Pb were observed. The possible processes which can cause the observed anomalies in the composition of newly created chemical elements are discussed shortly

  9. Deuterium microbomb rocket propulsion

    OpenAIRE

    Winterberg, Friedwardt

    2008-01-01

    Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimeg...

  10. Development of Low-energy Deuterium Ion Implantation Method to replace Hydrogen Post-metal Annealing (PMA)

    International Nuclear Information System (INIS)

    Recently, deuterium gas anneal was introduced to replace hydrogen gas anneal. Deuterium incorporation compared with that of hydrogen at Si/SiO2 interface is known to improve the device reliability characteristics because deuterium desorption is substantially reduced as compared with hydrogen desorption due to isotope effect. Deuterium diffusion takes place primarily through the gate oxide because of the limited permeability of bulk Si, metal, and even poly to deuterium. In the case of large scale ICs, therefore, the ability of deuterium to diffusion within the very thin SiO2 layer may be severely impeded, impacting the large-area devices used in peripheral circuits

  11. Tritium catalyzed deuterium tokamaks

    International Nuclear Information System (INIS)

    A preliminary assessment of the promise of the Tritium Catalyzed Deuterium (TCD) tokamak power reactors relative to that of deuterium-tritium (D-T) and catalyzed deuterium (Cat-D) tokamaks is undertaken. The TCD mode of operation is arrived at by converting the 3He from the D(D,n)3He reaction into tritium, by neutron capture in the blanket; the tritium thus produced is fed into the plasma. There are three main parts to the assessment: blanket study, reactor design and economic analysis and an assessment of the prospects for improvements in the performance of TCD reactors (and in the promise of the TCD mode of operation, in general)

  12. Deuterium thermodesorption from pyrographite materials

    International Nuclear Information System (INIS)

    Experimental results on the deuterium thermodesorption from pyrographite materials implanted with 25 keV ions to a fluence ranging from 1 · 1017 cm-2 to 8 · 10 18 cm-2 are reported. The deuterium release were studied during implantation. To investigate the process of deuterium desorption the pyrographite samples were neutron irradiated to a fluence of 1 · 1019...1 · 10 21 cm-2 in the temperature interval 70...80 degree C prior to deuterium implantation

  13. The primordial abundance of deuterium: ionization correction

    Science.gov (United States)

    Cooke, Ryan; Pettini, Max

    2016-01-01

    We determine the relative ionization of deuterium and hydrogen in low metallicity damped Lyman α (DLA) and sub-DLA systems using a detailed suite of photoionization simulations. We model metal-poor DLAs as clouds of gas in pressure equilibrium with a host dark matter halo, exposed to the Haardt & Madau background radiation of galaxies and quasars at redshift z ≃ 3. Our results indicate that the deuterium ionization correction correlates with the H I column density and the ratio of successive ion stages of the most commonly observed metals. The N(N II)/N(N I) column density ratio provides the most reliable correction factor, being essentially independent of the gas geometry, H I column density, and the radiation field. We provide a series of convenient fitting formulae to calculate the deuterium ionization correction based on observable quantities. The ionization correction typically does not exceed 0.1 per cent for metal-poor DLAs, which is comfortably below the current measurement precision (2 per cent). However, the deuterium ionization correction may need to be applied when a larger sample of D/H measurements becomes available.

  14. Observation of increased space-charge limited thermionic electron emission current by neutral gas ionization in a weakly-ionized deuterium plasma

    International Nuclear Information System (INIS)

    The thermionic electron emission current emitted from a laser-produced hot spot on a tungsten target in weakly-ionized deuterium plasma is measured. It is found to be one to two orders of magnitude larger than expected for bipolar space charge limited thermionic emission current assuming an unperturbed background plasma. This difference is attributed to the plasma being modified by ionization of background neutrals by the emitted electrons. This result indicates that the allowable level of emitted thermionic electron current can be significantly enhanced in weakly-ionized plasmas due to the presence of large neutral densities

  15. In-vessel tritium inventory in ITER evaluated by deuterium retention in carbon dust

    International Nuclear Information System (INIS)

    In order to estimate the in-vessel tritium inventory in carbon dust in ITER, deuterium gas absorption and deuterium ion irradiation experiments were conducted for a carbon dust prepared by using electron beam evaporation of graphite. The amount of deuterium retained after the deuterium gas absorption was very low, with an atomic ratio of D/C=10-3. The amount of deuterium retained after the deuterium ion irradiation was very similar to that for graphite. The deuterium concentration becomes close to zero if the wall temperature in the divertor wall region is higher than 1000 K. Co-deposited carbon dust was prepared by using a deuterium arc discharge apparatus with carbon electrodes at different gas pressure and substrate temperature. The co-deposited carbon dust had the largest deuterium concentration. In ITER conditions with a gas pressure of 1 Pa and wall temperature of 573 K, the deuterium concentration becomes approximately D/C=0.2. In DT discharges, the tritium concentration becomes T/C=0.1. This value is presumed to be the highest concentration in carbon dust in ITER. The present result shows that the accumulation speed of the in-vessel tritium inventory is lower than that predicted so far. (author)

  16. In-vessel tritium inventory in ITER evaluated by deuterium retention of carbon dust

    International Nuclear Information System (INIS)

    In order to estimate in-vessel tritium inventory of carbon dust, deuterium gas absorption and deuterium ion irradiation experiments were conducted for a carbon dust prepared by using electron beam evaporation for graphite. The retained amount of deuterium after the deuterium gas absorption was very low, D/C=10-3 in the atomic ratio. The retained amount of deuterium after the deuterium ion irradiation was very similar with that for graphite. The deuterium concentration becomes close to zero if the wall temperature at divertor wall region is higher than 1000 K. Co-deposited carbon dust was prepared by using a deuterium arc discharge apparatus with carbon electrodes at different gas pressure and substrate temperature. The co-deposited carbon dust had a largest deuterium concentration. In the ITER condition with gas pressure of 1 Pa and wall temperature of 573 K, the deuterium concentration in the atomic ratio becomes approximately D/C=0.2. In DT discharge, the tritium concentration in the atomic ratio becomes T/C=0.1. This value is presumed to be a highest concentration of carbon dust in ITER. The present result shows that the accumulation speed of in-vessel tritium inventory is lower than that predicted so far. (author)

  17. Production of hydrogen and deuterium negative ions in an electron cyclotron resonance driven plasma

    Energy Technology Data Exchange (ETDEWEB)

    Dougar-Jabon, V.D. [Industrial Univ. of Santander, Bucaramanga (Colombia)

    2001-04-01

    An electron cyclotron resonance source with driven plasma rings for hydrogen isotope ion production is studied. Extracted currents of positive and negative ions depending on gas pressure, microwave power value and extraction voltage are obtained. The study shows that the negative ion yield is an order of magnitude higher than the yield of positive particles when a driven ring is in contact with the surface of the plasma electrode. The production of negative ions of deuterium, D{sup -}, is close to the production of negative ions of light hydrogen isotope, H{sup -}. The comparison of the experimental data with the calculated ones shows that the most probable process of the H{sup -} and D{sup -} ion formation in the electron cyclotron driven plasma is dissociative attachment of electrons to molecules in high Rydberg states. For hydrogen ions and ions of deuterium, the negative current at a microwave power of 200 W through a 3-mm aperture and 8 kV extraction voltage are 4.7 mA and 3.1 mA respectively. (orig.)

  18. Deuterium fractionation in the Ophiuchus molecular cloud⋆

    Science.gov (United States)

    Punanova, A.; Caselli, P.; Pon, A.; Belloche, A.; André, Ph.

    2016-03-01

    Context. In cold (T 104 cm-3) interstellar clouds, molecules such as CO are significantly frozen onto dust grain surfaces. Deuterium fractionation is known to be very efficient in these conditions as CO limits the abundance of H3+, which is the starting point of deuterium chemistry. In particular, N2D+ is an excellent tracer of dense and cold gas in star-forming regions. Aims: We measure the deuterium fraction, RD, and the CO depletion factor, fd, towards a number of starless and protostellar cores in the L1688 region of the Ophiuchus molecular cloud complex and search for variations based upon environmental differences across L1688. The kinematic properties of the dense gas traced by the N2H+ and N2D+ (1-0) lines are also discussed. Methods: Deuterium fraction has been measured via observations of the J = 1-0 transition of N2H+ and N2D+ towards 33 dense cores in different regions of L1688. We estimated the CO depletion factor using C17O(1-0) and 850 μm dust continuum emission from the SCUBA survey. We carried out all line observations with the IRAM 30 m antenna. Results: The dense cores show large (≃2-40%) deuterium fractions with significant variations between the sub-regions of L1688. The CO depletion factor also varies from one region to another (between ≃1 and 7). Two different correlations are found between deuterium fraction and CO depletion factor: cores in regions A, B2, and I show increasing RD with increasing fd, similar to previous studies of deuterium fraction in pre-stellar cores; cores in regions B1, B1B2, C, E, F, and H show a steeper RD - fd correlation with large deuterium fractions occurring in fairly quiescent gas with relatively low CO freeze-out factors. These are probably recently formed, centrally concentrated starless cores, which have not yet started the contraction phase towards protostellar formation. We also find that the deuterium fraction is affected by the amount of turbulence, dust temperature, and distance from heating sources

  19. Deuterium ion fluxes to probes in the PLT edge plasma

    International Nuclear Information System (INIS)

    Using secondary ion mass spectrometry and nuclear reaction analysis, we have measured deuterium trapped in carbon samples exposed to deuterium discharges in PLT. From these data we infer that the fluxes range from 2 x 1015 to 3 x 1017 cm-2 s-1, and the energies range from 60 to 225 eV. Studies have been made on the effect of gas puffing and plasma position. (orig.)

  20. Primordial Deuterium Abundance and Cosmic Baryon Density

    OpenAIRE

    Hogan, Craig J.

    1994-01-01

    The comparison of cosmic abundances of the light elements with the density of baryonic stars and gas in the universe today provides a critical test of big bang theory and a powerful probe of the nature of dark matter. A new technique allows determination of cosmic deuterium abundances in quasar absorption clouds at large redshift, allowing a new test of big bang homogeneity in diverse, very distant systems. The first results of these studies are summarized, along with their implications. The ...

  1. Experimental study on the influence of charge exchange on the stopping power in the interaction of chlorine with a gas and a deuterium plasma; Etude experimentale de l`influence des echanges de charges sur le pouvoir d`arret dans l`interaction d`ions chlore avec un gaz et un plasma de deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Nectoux, Marie [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1998-01-06

    This thesis is placed in the context of the physics of energy deposition of a multicharged heavy ion beam in matter at intermediate energies. The experiment gave measurements of energy loss as a function of final charge state for chlorine ions at 1.7 MeV/u in deuterium gas or plasma. In this way, we explore the influence of charge state evolution, depending on experimentally measured capture and ionization cross sections and the electron density of the target, on energy loss. The target is cylindrical and enclosed by two fast valves. The plasma is created in the gas by a discharge, which induces a magnetic perturbation of the beam (lens effect). This effect induces a divergent and misaligned outgoing beam. A simulation including charge state and velocity evolution of the projectile in flight in the magnetic field has been made in order to optimize beam analysis, to reach a precision better than 10{sup -3} in energy measurement. This study led to removal of the target to the `Split Pole`, a refocusing magnetic spectrometer. The first results obtained clearly show the dependence of energy loss on exit charge and especially on its evolution in the target. This is explained in terms of the lengths covered by the projectile in its successive charge states in the target, which depends on target electron density and the medium considered. In plasma, we observed an energy distribution with exit charge twice that observed in gas, because of a strong decrease of charge exchange. A comparison of data obtained in gas with stopping power calculated from Bethe-Bloch-Barkas theory leads to the necessity of including spatial extension of the projectile charge in the theory. (author) 81 refs., 62 figs., 5tabs.

  2. Deuterium microbomb rocket propulsion

    CERN Document Server

    Winterberg, Friedwardt

    2008-01-01

    Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

  3. Deuterium labeled cannabinoids

    International Nuclear Information System (INIS)

    Complex reactions involving ring opening, ring closure and rearrangements hamper complete understanding of the fragmentation processes in the mass spectrometric fragmentation patterns of cannabinoids. Specifically labelled compounds are very powerful tools for obtaining more insight into fragmentation mechanisms and ion structures and therefore the synthesis of specifically deuterated cannabinoids was undertaken. For this, it was necessary to investigate the preparation of cannabinoids, appropriately functionalized for specific introduction of deuterium atom labels. The results of mass spectrometry with these labelled cannabinoids are described. (Auth.)

  4. Molecular dynamics simulation of deuterium trapping and bubble formation in tungsten

    International Nuclear Information System (INIS)

    Highlights: ► Deuterium tungsten interaction was simulated using classical molecular dynamic methods. ► Low energy deuterium atoms tend to affix to high temperature tungsten surface. ► Tungsten substrate temperature barely affects the low energy deuterium implantation depth. ► Deuterium bubble formation resulting from near surface super-saturation was predicted. -- Abstract: The interaction between plasma particles and tungsten as plasma facing material is one of the critical issues in successfully using tungsten in Tokamak reactors environment. The deuterium bombardment of monocrystalline tungsten was modeled by molecular dynamics simulation using LAMMPS code and Tersoff type interatomic potential. The deuterium trapping rate, implantation depth, and the stopping time in tungsten at several temperatures ranging from 600 to 2000 K bombarded by 5–100 eV deuterium atoms were simulated. Deuterium bubble formation at near tungsten surface was also studied. Irradiated monocrystalline tungsten became amorphous state prior to deuterium cluster formation, and gas bubbles were observed in the 600, 900, and 1200 K tungsten samples. The formation of gas bubbles were caused by the near surface deuterium super-saturation region and the subsequent plastic deformation induced by the local high gas pressure

  5. 多孔钯块材的脉冲烧结制备及其气体载氘行为%Pulse Sintering Preparation of Porous Palladium Bulk and Its Deuterium Gas Loading Behavior

    Institute of Scientific and Technical Information of China (English)

    李梦; 杨文锋; 刘颖; 陆光达; 涂铭旌

    2008-01-01

    High-speed deuterium loading in palladium is of great importance in the research of Metal-Hydrogen isotope system and applications of hydrogen energy.In this paper,porous Pd bulk prepared by a new pulse sintering technology is studied.The microstructure and phase of the porous Pd bulk are characterized by SEM and XRD.In addition,the deuterium gas loading behavior of the porous Pd bulk is investigated.The results show that clean porous Pd bulk with porosity of 81.6% can be prepared.The initial loading rate of deuterium in the porous Pd bulk is high but drops quickly.90%of the loading can be completed within the initial 80S.The loading rate comes to a very low level and decreases slowly about 10S after the beginning ofthe loading.%钯材的高速载氘对金属-氢同位素系统和氢能应用领域的研究具有重要的意义.本文研究了以海绵钯粉为原料通过脉冲烧结制备多孔钯块材的新工艺,用SEM和XRD分析了制备的多孔钯块材的微观结构形貌和相组成,并进一步研究了多孔钯块材的气体载氘行为.结果表明,采用脉冲烧结工艺可制备出孔隙率为81.6%的纯净多孔钯块材,氘在该钯材中的初始载入速度较高但迅速降低,80 s内即可完成约90%氘的载入;载氘开始约10 s后,氘的载入速度下降到较低的水平并缓慢衰减.

  6. Heterogeneous Catalysis: Deuterium Exchange Reactions of Hydrogen and Methane

    Science.gov (United States)

    Mirich, Anne; Miller, Trisha Hoette; Klotz, Elsbeth; Mattson, Bruce

    2015-01-01

    Two gas phase deuterium/hydrogen exchange reactions are described utilizing a simple inexpensive glass catalyst tube containing 0.5% Pd on alumina through which gas mixtures can be passed and products collected for analysis. The first of these exchange reactions involves H[subscript 2] + D[subscript 2], which proceeds at temperatures as low as 77…

  7. The Primordial Abundance of Deuterium: Ionization correction

    CERN Document Server

    Cooke, Ryan

    2015-01-01

    We determine the relative ionization of deuterium and hydrogen in low metallicity damped Lyman-alpha (DLA) and sub-DLA systems using a detailed suite of photoionization simulations. We model metal-poor DLAs as clouds of gas in pressure equilibrium with a host dark matter halo, exposed to the Haardt & Madau (2012) background radiation of galaxies and quasars at redshift z~3. Our results indicate that the deuterium ionization correction correlates with the H I column density and the ratio of successive ion stages of the most commonly observed metals. The N(N II) / N(N I) column density ratio provides the most reliable correction factor, being essentially independent of the gas geometry, H I column density, and the radiation field. We provide a series of convenient fitting formulae to calculate the deuterium ionization correction based on observable quantities. The ionization correction typically does not exceed 0.1 per cent for metal-poor DLAs, which is comfortably below the current measurement precision (2...

  8. Counter-diffusion and -permeation of deuterium and hydrogen through metals

    Energy Technology Data Exchange (ETDEWEB)

    Kizu, Kaname; Tanabe; Tetsuo [Nagoya Univ. (Japan)

    1998-03-01

    The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D{sub 2} pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H{sub 2} gas at the permeated side of D{sub 2}. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D{sub 2} from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

  9. Counter-diffusion and -permeation of deuterium and hydrogen through metals

    International Nuclear Information System (INIS)

    The first experiments for counter-diffusion and -permeation of deuterium and hydrogen through palladium were performed. Deuterium permeation rates against D2 pressure were measured under the condition where hydrogen permeated to opposite direction by supplying H2 gas at the permeated side of D2. It was found that not a small amount of deuterium was clearly permeated even if the deuterium pressure was much smaller than the hydrogen pressure. Deuterium permeation rate was gradually reduced by increasing the counter H permeation. The deuterium permeation rate under the counter H permeation is well represented by a simple model in which the ratio of the deuterium permeation rates with and without the counter H permeation was proportional to the fractional concentration of deuterium in the bulk. As increasing the hydrogen counter flow, however, the deuterium permeation rate deviates from the model. This means that adsorption (absorption) of D2 from gas phase is inhibited and surface recombination of deuterium is blocked by hydrogen. (author)

  10. Counter-diffusion and counter-permeation of deuterium and hydrogen through palladium

    International Nuclear Information System (INIS)

    Experiments for counter-diffusion and counter-permeation of deuterium and hydrogen through a palladium membrane (25 μm thick) were performed. Deuterium permeation rates as a function of upstream D2 pressure were measured under condition where hydrogen permeated in the opposite direction by supplying H2 gas at the 'other' side (downstream, corresponding to D permeation) of the membrane. It was found that significant deuterium permeation occurred even when the deuterium upstream pressure was much smaller than the hydrogen downstream pressure. The deuterium permeation rate was gradually reduced by increasing the downstream H2 pressure and the corresponding counter H permeation. The deuterium permeation rate under counter H permeation can be represented reasonably well by a simple model in which the ratio of the deuterium permeation rates with and without counter H permeation are assumed to be proportional to the fractional concentration of deuterium in the bulk. However, as the hydrogen counter flow increases, the deuterium permeation rate deviates from the model. This implies that adsorption (absorption) of D2 from the gas phase may be inhibited, and also surface recombination of deuterium may be blocked by hydrogen. (orig.)

  11. Properties of thick GEM in low-pressure deuterium

    International Nuclear Information System (INIS)

    Deuteron inelastic scattering (d, d') provides a promising spectroscopic tool to study nuclear incompressibility. In studies of deuteron inelastic scattering of unstable nuclei, measurements of low-energy recoiled particles is very important. In order to perform these measurements, we are developing a GEM-TPC based gaseous active target, called CAT (Center for nuclear study Active Target), operated with pure deuterium gas. The CAT has been tested with deuterium gas at 1 atm and 100-μm-thick GEMs. The low-pressure operation of CAT is planned in order to improve the detection capability for lower-energy recoil particles. A 400 μm-thick gas electron multiplier (THGEM) was chosen for the low-pressure operation of CAT. However, the properties of THGEM in low-pressure deuterium are currently undocumented. In this work, the performance of THGEM with low-pressure pure deuterium gas has been investigated. The effective gas gain of THGEM has been measured in various conditions using a 5.5-MeV 241Am alpha source. The effective gas gain was measured for 0.2-, 0.3- and 0.4-atm deuterium gas and a gas gain of about 103 was achieved by a double THGEM structure at 0.2 atm. The maximum achieved gain decreased with increasing gas pressure. The dependences of the effective gas gain on the electric field strengths of the drift, transfer and induction regions were investigated. The gain stability as a function of time in hydrogen gas was also tested and a relaxation time of THGEM of about 60 hours was observed with a continuous irradiation of alpha particles, which is significantly longer than previous studies have reported. We have tried to evaluate the gas gain of THGEM in deuterium gas by considering only the Townsend ionization process; however, it turned out that more phenomenological aspects, such as transfer efficiency, should be included in the evaluation. The basic properties of THGEM in low-pressure deuterium have been investigated for the first time

  12. Deuterium effects in cancer biology

    International Nuclear Information System (INIS)

    Since its discovery many experiments were conducted for explaining the effects of deuterium on biological systems. It was observed, in many studies, that by increasing the deuterium concentration, structural, metabolic and functional alterations at different extents are produced, which can lead to organism's death. On the other hand effects of concentration reduction are much less studied. Existing data in literature, with regard to intrinsic deuterium reduction effects on different carcinomas are rather scarce. In vitro studies of deuterium level reduction has evidenced an inhibiting effect upon the cellular proliferation in different tumoral cellular lines: M14 cellular lines (human melanoma), PC3 (prostate cancer) and MCF7 (breast cancer). In vivo researches made on experimental tumours, have shown that the deuterium level reduction determines partial or complete regressions in xenotransplanted tumours, while in veterinary oncological clinic, partial or total tumoral regression were observed in different spontaneous tumours in dogs and cats. (authors)

  13. Variable-aperture screen

    Science.gov (United States)

    Savage, George M.

    1991-01-01

    Apparatus for separating material into first and second portions according to size including a plurality of shafts, a plurality of spaced disks radiating outwardly from each of the shafts to define apertures and linkage interconnecting the shafts for moving the shafts toward or away from one another to vary the size of the apertures while the apparatus is performing the separating function.

  14. Mastering Apple Aperture

    CERN Document Server

    Fitzgerald, Thomas

    2013-01-01

    Written in a conversational style, the author will share his knowledge on advanced Aperture topics with detailed discussions of advanced topics, the theory behind some of those topics and lots of hints and tips for ways to improve your workflow.Photographer's who have a basic understanding of Aperture

  15. Synthetic Aperture Sequential Beamforming

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2008-01-01

    A synthetic aperture focusing (SAF) technique denoted Synthetic Aperture Sequential Beamforming (SASB) suitable for 2D and 3D imaging is presented. The technique differ from prior art of SAF in the sense that SAF is performed on pre-beamformed data contrary to channel data. The objective is to...

  16. Muon Capture in Deuterium

    CERN Document Server

    Ricci, P; Mosconi, B; Smejkal, J

    2009-01-01

    Model dependence of the capture rates of the negative muon capture in deuterium is studied starting from potential models and the weak two-body meson exchange currents constructed in the tree approximation and also from an effective field theory. The tree one-boson exchange currents are derived from the hard pion chiral Lagrangians of the $N \\Delta \\pi \\rho \\omega a_1$ system. If constructed in conjunction with the one-boson exchange potentials, the capture rates can be calculated consistently. On the other hand, the effective field theory currents, constructed within the heavy baryon chiral perturbation theory, contain a low energy constant $\\hat d ^R$ that cannot be extracted from data at the one-particle level nor determined from the first principles. Comparative analysis of the results for the doublet transition rate allows us to extract the constant $\\hat d ^R$.

  17. Deuterium Fractionation in the Ophiuchus Molecular Cloud

    CERN Document Server

    Punanova, A; Pon, A; Belloche, A; André, Ph

    2015-01-01

    Aims. We measure the deuterium fraction, RD, and the CO-depletion factor, fd, toward a number of starless and protostellar cores in the L1688 region of the Ophiuchus molecular cloud complex and search for variations based upon environmental differences across L1688. The kinematic properties of the dense gas traced by the N2H+ and N2D+ (1-0) lines are also discussed. Methods. RD has been measured via observations of the J=1-0 transition of N2H+ and N2D+ toward 33 dense cores in different regions of L1688. fd estimates have been done using C17O(1-0) and 850 micron dust continuum emission from the SCUBA survey. All line observations were carried out with the IRAM 30 meter antenna. Results. The dense cores show large (2-40%) deuterium fractions, with significant variations between the sub-regions of L1688. The CO-depletion factor also varies from one region to another (1-7). Two different correlations are found between deuterium fraction and CO-depletion factor: cores in regions A, B2 and I show increasing RD wit...

  18. Polarized deuterium internal target at AmPS (NIKHEF)

    Science.gov (United States)

    Ferro-Luzzi, M.; Zhou, Z.-L.; van den Brand, J. F. J.; Bulten, H. J.; Alarcon, R.; van Bakel, N.; Botto, T.; Bouwhuis, M.; van Buuren, L.; Comfort, J.; Doets, M.; Dolfini, S.; Ent, R.; Geurts, D.; Heimberg, P.; Higinbotham, D. W.; de Jager, C. W.; Lang, J.; de Lange, D. J.; Norum, B.; Passchier, I.; Poolman, H. R.; Six, E.; Steijger, J.; Szczerba, D.; Unal, O.; de Vries, H.

    1998-01-01

    We describe the polarized deuterium target internal to the NIKHEF medium-energy electron storage ring. Tensor polarized deuterium was produced in an atomic beam source and injected into a storage cell target. A Breit-Rabi polarimeter was used to monitor the injected atomic beam intensity and polarization. An electrostatic ion-extraction system and a Wien filter were utilized to measure on-line the atomic fraction of the target gas in the storage cell. This device was supplemented with a tensor polarization analyzer using the neutron anisotropy of the 3H(d,n)α reaction at 60 keV. This method allows determining the density-averaged nuclear polarization of the target gas, independent of spatial and temporal variations. We address issues important for polarized hydrogen/deuterium internal targets, such as the effects of spin-exchange collisions and resonant transitions induced by the RF fields of the charged particle beam.

  19. Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

    CERN Document Server

    Anders, M; Bellini, A; Aliotta, M; Bemmerer, D; Broggini, C; Caciolli, A; Costantini, H; Corvisiero, P; Davinson, T; Elekes, Z; Erhard, M; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Junker, M; Lemut, A; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Alvarez, C Rossi; Scott, D; Somorjai, E; Straniero, O; Szücs, T

    2013-01-01

    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction....

  20. Sub-Aperture Interferometers

    Science.gov (United States)

    Zhao, Feng

    2010-01-01

    Sub-aperture interferometers -- also called wavefront-split interferometers -- have been developed for simultaneously measuring displacements of multiple targets. The terms "sub-aperture" and "wavefront-split" signify that the original measurement light beam in an interferometer is split into multiple sub-beams derived from non-overlapping portions of the original measurement-beam aperture. Each measurement sub-beam is aimed at a retroreflector mounted on one of the targets. The splitting of the measurement beam is accomplished by use of truncated mirrors and masks, as shown in the example below

  1. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake.

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis. PMID:26620531

  2. Primordial Deuterium Abundance Measurements

    CERN Document Server

    Levshakov, S A; Takahara, F; Levshakov, Sergei A.; Kegel, Wilhelm H.; Takahara, Fumio

    1997-01-01

    Deuterium abundances measured recently from QSO absorption-line systems lie in the range from 3 10^{-5} to 3 10^{-4}, which shed some questions on standard big bang theory. We show that this discordance may simply be an artifact caused by inadequate analysis ignoring spatial correlations in the velocity field in turbulent media. The generalized procedure (accounting for such correlations) is suggested to reconcile the D/H measurements. An example is presented based on two high-resolution observations of Q1009+2956 (low D/H) [1,2] and Q1718+4807 (high D/H) [8,9]. We show that both observations are compatible with D/H = 4.1 - 4.6 10^{-5}, and thus support SBBN. The estimated mean value = 4.4 10^{-5} corresponds to the baryon-to-photon ratio during SBBN eta = 4.4 10^{-10} which yields the present-day baryon density Omega_b h^2 = 0.015.

  3. Characterization of water exchange and two-phase flow in porous gas diffusion materials by hydrogen-deuterium contrast neutron radiography

    Science.gov (United States)

    Manke, Ingo; Hartnig, Christoph; Kardjilov, Nikolay; Messerschmidt, Matthias; Hilger, André; Strobl, Markus; Lehnert, Werner; Banhart, John

    2008-06-01

    Liquid water exchange in two-phase flows within hydrophobic porous gas diffusion materials of polymer electrolyte membrane fuel cells was investigated spatially resolved with H-D contrast neutron radiography. A commonly used one-phase model is sufficient to describe water exchange characteristics at low water production rates. At higher rates, however, a significantly higher exchange velocity is found than predicted by a simple model. A new model for the water transport is derived based on an eruptive mechanism guided by Haines jumps, which is supported by recent experimental findings and leads to a very good agreement with the experiments.

  4. Deuterium absorption and material phase characteristics of Zr2Fe

    International Nuclear Information System (INIS)

    Scanning electron microscope (SEM) images of polished surfaces, electron probe microanalysis, and X-ray powder diffractometry indicated the presence of a continuous Zr2Fe phase with secondary phases of ZrFe2, Zr5FeSn, α-Zr, and Zr6Fe3O. A statistically-designed experiment to determine the effects of temperature, time, and vacuum quality On activation of St 198 revealed that when activated at low temperature (350 degrees C) deuterium absorption rate was slower when the vacuum quality was pwr (2.5 Pa vs. 3x10-4 Pa). However, at higher activation temperature (500 degrees C), deuterium absorption rate was fast and was independent of vacuum quality. Deuterium pressure-composition-temperature (P-C-T) data are reported for St 198 in the temperature range 200--500 degrees C. The P-C-T data over the full range of deuterium loading and at temperatures of 350 degrees C and below is described by: K0e-(ΔHα/RT)=PD2q2/(q*-q)2 where ΔHα and K0 have values of 101.8 kJ·mole-1 and 3.24x10-8Pa-1, and q* is 15.998 kPa·L-1·g-1. At higher temperatures, one or more secondary reactions in the solid phase occur that slowly consume D2 from the gas phase. XRD suggests these reactions to be: 2 Zr2FeDx → x ZrD2 + x/3 ZrFe2 + (2 - 2/3x) Zr2Fe and Zr2FeDx + (2 -1/2x) D2 → ZrD2 + Fe, where 0 < x < 3. Reaction between gas phase deuterium and Zr2FC formed in the first reaction accounts for the observed consumption of deuterium from the gas phase by this reaction

  5. Deuterium desorption behavior of solid tritium breeding material, lithium titanate

    International Nuclear Information System (INIS)

    Several types of blanket module, solid breeder/water or helium cooling, LiPb breeder/helium cooling, liquid LiN and Flibe, have been developed toward both ITER and a demonstration reactor in Japan. In the solid breeder blanket cooled by water, pellets of Li2TiO3 will be employed as tritium breeding material. Structure material in this blanket is low activation ferritic steel, F82H. The operation temperature is limited below approximately 820 K owing to swelling caused by neutron irradiation. Tritium produced by fusion neutrons in this breeding material has to be desorbed under a blanket operation for tritium recovery to be easy. The blanket module, however, has a spatial distribution of temperature. Thus, the tritium desorption behavior has to be clarified in order to make a scheme for tritium recovery. In the present study, a solid breeding material, Li2TiO3, was irradiated by 1.7 keV deuterium ions, and an amount of retained deuterium and deuterium desorption behavior were investigated using a thermal desorption. Dependence of deuterium fluence on amount of retained deuterium was also obtained. In order to examine trapping mechanisms of deuterium in Li2TiO3, similar experiments were conducted for Li and Ti. Deuterium implanted to Li2TiO3 desorbed in forms of HD, D2, HDO and D2O. The amount of deuterium desorbed in form of HD was a few times larger than those of other gas species. The desorption peak appeared at 600 K, but significant desorption up to 900 K was observed. The range of temperature in the lithium titanate of the blanket module is assumed from 550 K to 1200 K. These results suggest that the tritium produced in the blanket is partly not desorbed. Thus, the spatial distribution of temperature in the blanket has to be controlled for the tritium to be desorbed during the operation. The desorption spectra of deuterium in Li2TiO3 were similar to those of Li. This suggests that most of implanted deuterium is trapped in forms of Li-D and Li-OD. Based upon the

  6. Deuterium exchange between hydrofluorocarbons and amines

    International Nuclear Information System (INIS)

    The invention consists of a process for obtaining a compound enriched in deuterium which comprises the known method of exposing a gaseous hydrofluorocarbon to infrared laser radiation of a predetermined frequency to selectively cause a chemical reaction involving hydrofluorocarbon molecules containing deuterium without substantially affecting hydrofluorocarbon molecules not containing deuterium, thereby producing, as reaction products, a compound enriched in deuterium and hydrofluorocarbon depleted in deuterium; combined with a new method, which comprises enriching the deuterium content of the depleted hydrofluorocarbon by contacting the depleted hydrofluorocarbon with an alkali metal amide and an amine having a concentration of deuterium at least that which will yield an increase in deuterium concentration of the hydrofluorocarbon upon equilibration, whereby the amine becomes depleted in deuterium

  7. Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy

    Science.gov (United States)

    Yu, Yaowei; Hu, Jiansheng; Wan, Zhao; Wu, Jinhua; Wang, Houyin; Cao, Bin

    2016-03-01

    Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ˜0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10-6-5.0 × 10-2 Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eV and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (PD2) and helium partial pressure (PHe) could be obtained. The result shows that deuterium partial pressure could be measured if PD2 > 10-6 Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if PHe/PD2 > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning.

  8. Mass separation of deuterium and helium with conventional quadrupole mass spectrometer by using varied ionization energy.

    Science.gov (United States)

    Yu, Yaowei; Hu, Jiansheng; Wan, Zhao; Wu, Jinhua; Wang, Houyin; Cao, Bin

    2016-03-01

    Deuterium pressure in deuterium-helium mixture gas is successfully measured by a common quadrupole mass spectrometer (model: RGA200) with a resolution of ∼0.5 atomic mass unit (AMU), by using varied ionization energy together with new developed software and dedicated calibration for RGA200. The new software is developed by using MATLAB with the new functions: electron energy (EE) scanning, deuterium partial pressure measurement, and automatic data saving. RGA200 with new software is calibrated in pure deuterium and pure helium 1.0 × 10(-6)-5.0 × 10(-2) Pa, and the relation between pressure and ion current of AMU4 under EE = 25 eV and EE = 70 eV is obtained. From the calibration result and RGA200 scanning with varied ionization energy in deuterium and helium mixture gas, both deuterium partial pressures (PD2 ) and helium partial pressure (PHe) could be obtained. The result shows that deuterium partial pressure could be measured if PD2 > 10(-6) Pa (limited by ultimate pressure of calibration vessel), and helium pressure could be measured only if PHe/PD2 > 0.45, and the measurement error is evaluated as 15%. This method is successfully employed in EAST 2015 summer campaign to monitor deuterium outgassing/desorption during helium discharge cleaning. PMID:27036832

  9. Neutron-induced background by an {alpha}-beam incident on a deuterium gas target and its implications for the study of the {sup 2}H({alpha},{gamma}){sup 6}Li reaction at LUNA

    Energy Technology Data Exchange (ETDEWEB)

    Anders, M.; Bemmerer, D.; Elekes, Z.; Marta, M. [Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden (Germany); Trezzi, D.; Mazzocchi, C. [INFN, Sezione di Milano, Milano (Italy); Bellini, A.; Costantini, H.; Corvisiero, P.; Lemut, A.; Prati, P. [Universita di Genova (Italy); INFN, Sezione di Genova, Dipartimento di Fisica, Genova (Italy); Aliotta, M.; Davinson, T.; Scott, D. [University of Edinburgh, SUPA, School of Physics and Astronomy, Edinburgh (United Kingdom); Broggini, C.; Caciolli, A.; Erhard, M.; Menegazzo, R.; Rossi Alvarez, C. [INFN, Sezione di Padova, Padova (Italy); Formicola, A.; Junker, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Fueloep, Zs.; Gyuerky, G.; Somorjai, E.; Szuecs, T. [Institute of Nuclear Research (ATOMKI), Debrecen (Hungary); Gervino, G. [Universita di Torino (Italy); INFN, Dipartimento di Fisica Sperimentale, Torino (Italy); Guglielmetti, A. [INFN, Sezione di Milano, Milano (Italy); Universita degli Studi di Milano, Milano (Italy); Gustavino, C. [INFN, Sezione di Roma ' ' La Sapienza' ' , Roma (Italy); Straniero, O. [INFN, Sezione di Napoli, Napoli (Italy); Osservatorio Astronomico di Collurania, Teramo (Italy); Collaboration: LUNA Collaboration

    2013-02-15

    The production of the stable isotope {sup 6}Li in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological {sup 6}Li plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of {sup 7}Li abundances and would point to a predominantly primordial origin of {sup 6}Li, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang {sup 6}Li production must be revisited. The main production channel for {sup 6}Li in the Big Bang is the {sup 2}H({alpha},{gamma}){sup 6}Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the {sup 2}H(d,n){sup 3}He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400keV {alpha}-beam energy and for comparison also using an americium-beryllium neutron source. (orig.)

  10. Laser-driven polarized hydrogen and deuterium internal targets

    International Nuclear Information System (INIS)

    After completing comprehensive tests of the performance of the source with both hydrogen and deuterium gas, we began tests of a realistic polarized deuterium internal target. These tests involve characterizing the atomic polarization and dissociation fraction of atoms in a storage cell as a function of flow and magnetic field, and making direct measurements of the average nuclear tensor polarization of deuterium atoms in the storage cell. Transfer of polarization from the atomic electron to the nucleus as a result of D-D spin-exchange collisions was observed in deuterium, verifying calculations suggesting that high vector polarization in both hydrogen and deuterium can be obtained in a gas in spin temperature equilibrium without inducing RF transitions between the magnetic substates. In order to improve the durability of the system, the source glassware was redesigned to simplify construction and installation and eliminate stress points that led to frequent breakage. Improvements made to the nuclear polarimeter, which used the low energy 3H(d,n)4He reaction to analyze the tensor polarization of the deuterium, included installing acceleration lenses constructed of wire mesh to improve pumping conductance, construction of a new holding field coil, and elimination of the Wien filter from the setup. These changes substantially simplified operation of the polarimeter and should have reduced depolarization in collisions with the wall. However, when a number of tests failed to show an improvement of the nuclear polarization, it was discovered that extended operation of the system with a section of teflon as a getter for potassium caused the dissociation fraction to decline with time under realistic operating conditions, suggesting that teflon may not be a suitable material to eliminate potassium from the target. We are replacing the teflon surfaces with drifilm-coated ones and plan to continue tests of the polarized internal target in this configuration

  11. High Energy, Narrow Linewidth 1572nm Eryb-Fiber Based MOPA for a Multi-Aperture CO2 Trace-Gas Laser Space Transmitter

    Science.gov (United States)

    Engin, Doruk; Mathason, Brian; Stephen, Mark; Yu, Anthony; Cao, He; Fouron, Jean-Luc; Storm, Mark

    2016-01-01

    Accurate global measurements of tropospheric CO2 mixing ratios are needed to study CO2 emissions and CO2 exchange with the land and oceans. NASA Goddard Space Flight Center (GSFC) is developing a pulsed lidar approach for an integrated path differential absorption (IPDA) lidar to allow global measurements of atmospheric CO2 column densities from space. Our group has developed, and successfully flown, an airborne pulsed lidar instrument that uses two tunable pulsed laser transmitters allowing simultaneous measurement of a single CO2 absorption line in the 1570 nm band, absorption of an O2 line pair in the oxygen A-band (765 nm), range, and atmospheric backscatter profiles in the same path. Both lasers are pulsed at 10 kHz, and the two absorption line regions are sampled at typically a 300 Hz rate. A space-based version of this lidar must have a much larger lidar power-area product due to the x40 longer range and faster along track velocity compared to airborne instrument. Initial link budget analysis indicated that for a 400 km orbit, a 1.5 m diameter telescope and a 10 second integration time, a 2 mJ laser energy is required to attain the precision needed for each measurement. To meet this energy requirement, we have pursued parallel power scaling efforts to enable space-based lidar measurement of CO2 concentrations. These included a multiple aperture approach consists of multi-element large mode area fiber amplifiers and a single-aperture approach consists of a multi-pass Er:Yb:Phosphate glass based planar waveguide amplifier (PWA). In this paper we will present our laser amplifier design approaches and preliminary results.

  12. Aperture distribution of rock fractures

    International Nuclear Information System (INIS)

    This thesis concerns the properties of the fracture void geometry of single rock fractures. It is suggested that the parameter aperture be used to describe the fracture void geometry and a definition of the aperture is proposed. The relation between void geometry and other fracture properties such as roughness, stiffness, conductivity and channelling are discussed. Different experimental techniques for aperture measurement have been developed in this work. The methods are applicable to fractures of different nature and size. A compilation of measurement results indicates that the spatial correlation (range) of fracture apertures increases with increasing mean aperture and that the range is correlated with the coefficient of variation. The existing data from aperture measurements and fracture flow experiments are still very scarce, in particular for fractures with large apertures. For future research, additional aperture measurements from fractures of different types is recommended. A further development of aperture measurement techniques suitable for field investigation is also suggested. 31 refs, 18 figs

  13. Deuterium retention and desorption behavior of co-deposited carbon film produced in gap

    International Nuclear Information System (INIS)

    Co-deposition of deuterium with carbon in an opening on a plasma-facing surface, a so-called 'gap', was simulated by using a deuterium arc discharge with carbon electrodes. The carbon deposition distribution and deuterium retention/desorption behavior of the carbon film were investigated. The amount of deposited carbon decreased exponentially with an increase of the distance from the gap entrance and more rapidly decreased with an increase in discharge gas pressure. The deuterium concentration in the carbon film increased with discharge gas pressure. At a high discharge gas pressure of 36 Pa, the atomic ratio of D/C in the carbon film reached as high as 0.9. Deuterium retained in the film desorbed mainly in the forms of D2, HD, CD4 and C2D4. The desorption behavior of retained deuterium depended on D/C. In a film with a high D/C ratio, desorption of D2 started at lower temperatures. The amount of desorbed hydrocarbons (CD4 and C2D4) increased with D/C. Carbon film with high D/C tended to contain a polymer-like structure, which could be related to the desorption behavior of the retained deuterium. (author)

  14. Injection of Deuterium Pellets

    DEFF Research Database (Denmark)

    Sørensen, H.; Andersen, P.; Andersen, S. A.; Andersen, Verner; Nielsen, Arne Nordskov; Sass, Bjarne Ove; Weisberg, Knud-Vilhelm

    1984-01-01

    A pellet injection system made for the TFR tokamak at Fontenay-aux-Roses, Paris is described. 0.12-mg pellets are injected with velocities of around 600-700 m/s through a 5-m long guide tube. Some details of a new light gas gun are given; with this gun, hydrogen pellets are accelerated to velocit...

  15. Production and injection of hydrogen-deuterium mixed pellet

    International Nuclear Information System (INIS)

    A mixed solid pellet of hydrogen and deuterium could be produced in the single pellet injector. The pellet is used to examine an improvement of plasma confinement in ion cyclotron range of frequency (ICRF) wave heated discharges. The mixed pellets were maken from the mixed gas with the different ratio of hydrogen to mixed gas (H + D). The composition of the pellet is not equal to that of the mixed gas before freezing. The in-flight mixed pellets with about 769 m/s keep their cylindrical shape, e.g. the pellets are not broken. The present results will indicate the possibility of pellet mixed deuterium and tritium, which will be necessary to in future thermonuclear fusion reactor. (author)

  16. Apodizer aperture for lasers

    Science.gov (United States)

    Jorna, Siebe; Siebert, Larry D.; Brueckner, Keith A.

    1976-11-09

    An aperture attenuator for use with high power lasers which includes glass windows shaped and assembled to form an annulus chamber which is filled with a dye solution. The annulus chamber is shaped such that the section in alignment with the axis of the incident beam follows a curve which is represented by the equation y = (r - r.sub.o).sup.n.

  17. The LHC dynamic aperture

    CERN Document Server

    Koutchouk, Jean-Pierre

    1999-01-01

    In 1996, the expected field errors in the dipoles and quadrupoles yielded a long-term dynamic aperture of some 8sigma at injection. The target was set to 12sigma to account for the limitations of our model (imperfections and dynamics). From scaling laws and tracking, a specification for the field imperfections yielding the target dynamic aperture was deduced. The gap between specification and expected errors is being bridged by i) an improvement of the dipole field quality, ii) a balance between geometric and persistent current errors, iii) additional correction circuits (a3 ,b4 ). With the goal in view, the emphasis has now turned to the sensitivity of the dynamic aperture to the optical parameters.The distortion of the dynamics at the lower amplitudes effectively reached by the particles is minimized by optimizing the distribution of the betatron phase advance. At collision energy, the dynamic aperture is limited by the field imperfections of the low-beta triplets, enhanced by the crossing angle. With corre...

  18. Apertured paraxial Bessel beams.

    Science.gov (United States)

    Umul, Yusuf Z

    2010-03-01

    The paraxial Bessel beam is obtained by applying an approximation in the wavenumbers. The scattering of the beams by a circular aperture in an absorbing screen is investigated. The scattered fields are expressed in terms of the Fresnel integrals by evaluating the Kirchhoff diffraction integral in the paraxial approximation. The results are examined numerically. PMID:20208927

  19. Synthetic Aperture Radar Interferometry

    Science.gov (United States)

    Rosen, P. A.; Hensley, S.; Joughin, I. R.; Li, F.; Madsen, S. N.; Rodriguez, E.; Goldstein, R. M.

    1998-01-01

    Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

  20. Thermal desorption of deuterium implanted into beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Markin, A.V.; Chernikov, V.N.; Zakharov, A.P. [Institute of Physical Chemistry, Moscow (Russian Federation)] [and others

    1995-09-01

    By means of TDS measurements it is shown that the desorption of deuterium from Be implanted with 5 keV D ions to fluences, {Phi}, from 1x10{sup 20} D/m{sup 2} to 1x10{sup 21} D/m{sup 2} proceeds in one high temperature stage B, while at {Phi} {ge} 1.2x10{sup 21}D/m{sup 2} one more stage A is added. The desorption maximum A is narrow and consists of two peaks A{sub 1} and A{sub 2} at about 460 K and 490 K, respectively. Peak A{sub 1} is attributed to the desorption of deuterium from the walls of opened channels formed under D ion implantation. Peak {sub A}2 is a consequence of the opening of a part of closed bubbles/channels to the outer surface. The position of maximum B shifts noticeably and nonsteadily on the fluence in a range from 850 to 1050 K. The origin of this maximum is the liberation of D atoms bound at vacancy complexes discussed previously by Wampler. The dependence of Tm(B) on the fluence is governed by the interaction of freely migrating D atoms with partly opened or fully closed gas cavity arrangements which are created under temperature ramping, but differently in specimens implanted with D ions to different fluences.

  1. Deuterium inventory in tungsten after plasma exposure. A microstructural survey

    International Nuclear Information System (INIS)

    highly reproducible exposure conditions, exposing all four types of specimens to the plasma simultaneously ensured that their retention behaviour could be directly compared. After two months of storage in a vacuum exsiccator, the long-term deuterium inventory of the specimens was analysed by depth-resolved nuclear reaction analysis and thermal desorption spectroscopy. Modifications of the specimen surfaces, in particular the formation of subsurface cracks and gas-filled subsurface cavities called blisters, were studied by a variety of optical and electron microscopy techniques, including in situ cross-sectioning with a focused ion beam. This extensive survey allowed finding a clear correlation between the initial dislocation density of the material and the observed deuterium retention, whereas the grain size, and therefore the density of grain boundaries, appeared to play a minor role. The binding energy of the dominant binding site, which is consequently assigned to dislocations, was determined by a detailed thermal desorption spectroscopy study of the specimen type with the highest dislocation density. It was also shown that defects capable of trapping significant amounts of deuterium can be produced during plasma exposure. Within the ion range of several nanometres, the tungsten surface is practically amorphised, which leads to observed local deuterium concentrations in the per cent range. Far beyond the ion range, blisters and cracks do not only retain deuterium in the form of molecular gas, but also produce a high density of defects in the surrounding tungsten lattice, most likely dislocations emitted near crack tips. A one-dimensional rate equation model was adapted to include these defect production mechanisms by an empirical term. By that, it was able to reproduce the fluence dependence of the deuterium retention as well as the shift of the main desorption peak for varying heating rates during thermal desorption spectroscopy.

  2. Search for parity mixing in hydrogen and deuterium

    International Nuclear Information System (INIS)

    A study has been made of the effects of parity mixing in hydrogen and deuterium with the intention of developing an apparatus capable of detecting parity mixing produced by the neutral current part of the weak interaction in these atoms. It is the purpose of the investigations reported to understand in detail the nature of each of these defects, and to provide the means to reduce them to the extent that precision measurements of C2/sup p/ and C2/sup d/ can be accomplished. To this end the magnetic field of the Mark II solenoid and a new precision solenoid have been measured and compared. The old solenoid is found to have field imperfections of a type and magnitude consistent with observed instrumental asymmetries in the Mark II experiment. The new solenoid is observed to be 10 to 100 times more homogeneous. In order to identify the source of a spurious electric field in the central part of the apparatus all electrodes were carefully electropolished and gold plated. Careful observations before and after showed that the spurious field is independent of cavity surface properties. A model was then generated which explained many features of the spurious field in terms of space charge generated by beam collisions with electrode apertures. Preparatory to studies in deuterium, various El and Ml matric elements were calculated and comparisons of systematic effects were made for hydrogen and deuterium atomic systems. In order to make practical a study of parity mixing in deuterium a special rf cavity with a Gaussian field distribution was first computer simulated, then tested in prototype form. 80 refs., 56 figs

  3. Deuterium burning in Jupiter interior

    OpenAIRE

    Coraddu, Massimo; Lissia, Marcello; Mezzorani, Giuseppe; Quarati, Piero

    2001-01-01

    We show that moderate deviations from the Maxwell-Boltzmann energy distribution can increase deuterium reaction rates enough to contribute to the heating of Jupiter. These deviations are compatible with the violation of extensivity expected from temperature and density conditions inside Jupiter.

  4. Solid deuterium centrifuge pellet injector

    International Nuclear Information System (INIS)

    Pellet injectors are needed to fuel long pulse tokamak plasmas and other magnetic confinement devices. For this purpose, an apparatus has been developed that forms 1.3-mm-diam pellets of frozen deuterium at a rate of 40 pellets per second and accelerates them to a speed of 1 km/s. Pellets are formed by extruding a billet of solidified deuterium through a 1.3-mm-diam nozzle at a speed of 5 cm/s. The extruding deuterium is chopped with a razor knife, forming 1.3-mm right circular cylinders of solid deuterium. The pellets are accelerated by synchronously injecting them into a high speed rotating arbor containing a guide track, which carries them from a point near the center of rotation to the periphery. The pellets leave the wheel after 1500 of rotation at double the tip speed. The centrifuge is formed in the shape of a centrifugal catenary and is constructed of high strength KEVLAR/epoxy composite. This arbon has been spin-tested to a tip speed of 1 km/s

  5. Survey of coded aperture imaging

    International Nuclear Information System (INIS)

    The basic principle and limitations of coded aperture imaging for x-ray and gamma cameras are discussed. Current trends include (1) use of time varying apertures, (2) use of ''dilute'' apertures with transmission much less than 50%, and (3) attempts to derive transverse tomographic sections, unblurred by other planes, from coded images

  6. Congenital pyriform aperture stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Osovsky, Micky [Schneider Pediatric Hospital, Department of Neonatology, Petach Tikvah (Israel); Rabin Medical Center, Department of Neonatology, Schneider Children' s Medical Center of Israel, Beilinson Campus, Petah Tikvah (Israel); Aizer-Danon, Anat; Horev, Gadi [Schneider Pediatric Hospital, Department of Pediatric Radiology, Petach Tikvah (Israel); Sirota, Lea [Schneider Pediatric Hospital, Department of Neonatology, Petach Tikvah (Israel)

    2007-01-15

    Nasal airway obstruction is a potentially life-threatening condition in the newborn. Neonates are obligatory nasal breathers. The pyriform aperture is the narrowest, most anterior bony portion of the nasal airway, and a decrease in its cross-sectional area will significantly increase nasal airway resistance. Congenital nasal pyriform aperture stenosis (CNPAS) is a rare, unusual form of nasal obstruction. It should be considered in the differential diagnosis of any neonate or infant with signs and symptoms of upper airway compromise. It is important to differentiate this level of obstruction from the more common posterior choanal stenosis or atresia. CNPAS presents with symptoms of nasal airway obstruction, which are often characterized by episodic apnea and cyclical cyanosis. (orig.)

  7. Complex Aperture Networks

    CERN Document Server

    Owladeghaffari, Hamed

    2009-01-01

    A complex network approach on a rough fracture is developed. In this manner, some hidden metric spaces (similarity measurements) between apertures profiles are set up and a general evolutionary network in two directions (in parallel and perpendicular to the shear direction) is constructed. Evaluation of the emerged network shows the connectivity degree (distribution) of network, after a transition step; fall in to the stable states which are coincided with the Gaussian distribution. Based on this event and real observations of the complex network changes, an algorithm (COmplex Networks on Apertures: CONA) is proposed in which evolving of a network is accomplished using preferential detachments and attachments of edges (based on a competition and game manner) while the number of nodes is fixed. Also, evolving of clustering coefficients and number of edges display similar patterns as well as are appeared in shear stress, hydraulic conductivity and dilation changes, which can be engaged to estimate shear strengt...

  8. Configurable Aperture Space Telescope

    Science.gov (United States)

    Ennico, Kimberly; Bendek, Eduardo

    2015-01-01

    In December 2014, we were awarded Center Innovation Fund to evaluate an optical and mechanical concept for a novel implementation of a segmented telescope based on modular, interconnected small sats (satlets). The concept is called CAST, a Configurable Aperture Space Telescope. With a current TRL is 2 we will aim to reach TLR 3 in Sept 2015 by demonstrating a 2x2 mirror system to validate our optical model and error budget, provide straw man mechanical architecture and structural damping analyses, and derive future satlet-based observatory performance requirements. CAST provides an alternative access to visible and/or UV wavelength space telescope with 1-meter or larger aperture for NASA SMD Astrophysics and Planetary Science community after the retirement of HST

  9. Synthetic Aperture Radiometer Systems

    Science.gov (United States)

    LeVine, David M.

    1999-01-01

    Aperture synthesis is a new technology for passive microwave remote sensing from space which has the potential to overcome the limitations set in the past by antenna size. This is an interferometric technique in which pairs of small antennas and signal processing are used to obtain the resolution of a single large antenna. The technique has been demonstrated successfully at L-band with the aircraft prototype instrument, ESTAR. Proposals have been submitted to demonstrate this technology in space (HYDROSTAR and MIRAS).

  10. Deuterium - depleted water. Achievements and perspectives

    International Nuclear Information System (INIS)

    Deuterium - depleted water represents water that has an isotopic content lower than 145 ppm D/(D+H) which is the natural isotopic content of water. The research conducted at ICSI Ramnicu Valcea, regarding deuterium - depleted water were completed by the following patents: - technique and installation for deuterium - depleted water production; - distilled water with low deuterium content; - technique and installation for the production of distilled water with low deuterium content; - mineralized water with low deuterium content and technique to produce it. The gold and silver medals won at international salons for inventions confirmed the novelty of these inventions. Knowing that deuterium content of water has a big influence on living organisms, beginning with 1996, the ICSI Ramnicu Valcea, deuterium - depleted water producer, co-operated with Romanian specialized institutes for biological effects' evaluation of deuterium - depleted water. The role of natural deuterium in living organisms was examined by using deuterium - depleted water instead of natural water. These investigations led to the following conclusions: 1. deuterium - depleted water caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the deuterium - depleted water persists after the removal of the vascular endothelium; -2. animals treated with deuterium - depleted water showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defence mechanism; 3, deuterium - depleted water stimulates immune defence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the numbers of polymorphonuclear neutrophils; 4. investigations regarding artificial

  11. The Evaluation and Quantitation of Dihydrogen Metabolism Using Deuterium Isotope in Rats

    OpenAIRE

    Hyspler, Radomir; Ticha, Alena; Schierbeek, Henk; Galkin, Alexander; Zadak, Zdenek

    2015-01-01

    Purpose: Despite the significant interest in molecular hydrogen as an antioxidant in the last eight years, its quantitative metabolic parameters in vivo are still lacking, as is an appropriate method for determination of hydrogen effectivity in the mammalian organism under various conditions.Basic Procedures: Intraperitoneally-applied deuterium gas was used as a metabolic tracer and deuterium enrichment was determined in the body water pool. Also, in vitro experiments were performed using bov...

  12. Quantum gases: spin-polarized atomic hydrogen and deuterium

    International Nuclear Information System (INIS)

    Properties of atomic gases, spin-polarized hydrogen and deuterium, are discussed. The underlying ideas required for stabilizing these gases against recombination to the molecular form are presented and experimental techniques are briefly described. The consequences of the presence of a helium surface for Bose Einstein Condensation (BEC) are discussed. It is shown that interactions between atoms on the surface are required to achieve sufficiently high gas phase densities for BEC to occur. (Auth.)

  13. Laser spectroscopy of muonic deuterium

    Science.gov (United States)

    Pohl, Randolf; Nez, François; Fernandes, Luis M. P.; Amaro, Fernando D.; Biraben, François; Cardoso, João M. R.; Covita, Daniel S.; Dax, Andreas; Dhawan, Satish; Diepold, Marc; Giesen, Adolf; Gouvea, Andrea L.; Graf, Thomas; Hänsch, Theodor W.; Indelicato, Paul; Julien, Lucile; Knowles, Paul; Kottmann, Franz; Le Bigot, Eric-Olivier; Liu, Yi-Wei; Lopes, José A. M.; Ludhova, Livia; Monteiro, Cristina M. B.; Mulhauser, Françoise; Nebel, Tobias; Rabinowitz, Paul; dos Santos, Joaquim M. F.; Schaller, Lukas A.; Schuhmann, Karsten; Schwob, Catherine; Taqqu, David; Veloso, João F. C. A.; Antognini, Aldo

    2016-08-01

    The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium μd is the exotic atom formed by a deuteron and a negative muon μ–. We measured three 2S-2P transitions in μd and obtain rd = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value rd = 2.1424(21) fm. The μd value is also 3.5σ smaller than the rd value from electronic deuterium spectroscopy. The smaller rd, when combined with the electronic isotope shift, yields a “small” proton radius rp, similar to the one from muonic hydrogen, amplifying the proton radius puzzle.

  14. 基于LMD包络谱熵及SVM的天然气管道微小泄漏孔径识别%Gas Pipeline Small Leak Aperture Classification Based on Local Mean Decomposition Envelope Spectrum Entropy and SVM

    Institute of Scientific and Technical Information of China (English)

    孙洁娣; 肖启阳; 温江涛; 王飞

    2014-01-01

    When small leak occurs in the natural gas pipeline, it is difficult to identify the leak scale and aperture. It is proposed a small leak aperture recognition method based on local mean decomposition(LMD) envelope spectrum entropy and SVM. The leakage signals are decomposed into a number of production functions(PFs) components which have physical significance instantaneous frequencies. And then calculate the PFs kurtosis values and according to this select the principal PF components which contain most of leakage information. Further the wavelet packet decomposition and band energy distribution method are used to analyze the principal PF components and then reconstruct them. The Hilbert transform is applied to these reconstructed principal PF components and the corresponding envelope spectrums are obtained. Combining the concept of information entropy, the envelope spectrum entropy is proposed and calculates the entropy values. The normalized envelope spectrum entropy as the leakage feature is input the support vector machine(SVM) and the leak aperture classification is accomplished. By analyzing the acquired pipeline leakage signals in the field experiments, the results show that this method can effectively identify the different leak apertures.%针对管道泄漏信号的非平稳特征以及管道泄漏孔径大小难以识别的问题,提出一种基于局域均值分解包络谱熵及支持向量机的识别方法。该方法对管道泄漏信号进行局域均值分解,得到若干个瞬时频率具有物理意义的乘积函数(production Function, PF)分量;计算各PF分量的峭度值并据此选出包含主要泄漏信息的分量作为主PF分量,对这些分量进一步采用小波包分解能量法进行分析并重构;再对重构后的主PF分量进行希尔伯特变换求取包络谱,结合信息熵的概念提出包络谱熵并计算熵值;将归一化包络谱熵作为泄漏信号特征输入支持向量机分类器中,用以区

  15. Deuterium and big bang nucleosynthesis

    International Nuclear Information System (INIS)

    Measurements of deuterium absorption in high redshift quasar absorption systems provide a direct inference of the deuterium abundance produced by big bang nucleosynthesis (BBN). With measurements and limits from five independent absorption systems, we place strong constraints on the primordial ratio of deuterium to hydrogen, (D/H)p = 3.4 ± 0.3 x 10-5 [1,2]. We employ a direct numerical treatment to improve the estimates of critical reaction rates and reduce the uncertainties in BBN predictions of D/H and 7Li/H by a factor of three[3] over previous efforts[4]. Using our measurements of (D/H)p and new BBN predictions, we find at 95% confidence the baryon density ρb = (3.6 ± 0.4) x 10-31 g cm-3 (Ωbh265 = 0.045 ± 0.006 in units of the critical density), and cosmological baryon-photon ratio η = (5.1 ± 0.6) x 10-10

  16. Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk

    Medical ultrasound imaging is used for many purposes, e.g. for localizing and classifying cysts, lesions, and other processes. Almost any mass is first observed using B-mode imaging and later classified using e.g. color flow, strain, or attenuation imaging. It is therefore important that the B...... and the limiting factor is the amount of memory IO resources available. An equally high demand for memory throughput is found in the computer gaming industry, where a large part of the processing takes place on the graphics processing unit (GPU). Using the GPU, a framework for synthetic aperture imaging...

  17. Single crystal diamond detector measurements of deuterium-deuterium and deuterium-tritium neutrons in Joint European Torus fusion plasmas

    Science.gov (United States)

    Cazzaniga, C.; Sundén, E. Andersson; Binda, F.; Croci, G.; Ericsson, G.; Giacomelli, L.; Gorini, G.; Griesmayer, E.; Grosso, G.; Kaveney, G.; Nocente, M.; Cippo, E. Perelli; Rebai, M.; Syme, B.; Tardocchi, M.

    2014-04-01

    First simultaneous measurements of deuterium-deuterium (DD) and deuterium-tritium neutrons from deuterium plasmas using a Single crystal Diamond Detector are presented in this paper. The measurements were performed at JET with a dedicated electronic chain that combined high count rate capabilities and high energy resolution. The deposited energy spectrum from DD neutrons was successfully reproduced by means of Monte Carlo calculations of the detector response function and simulations of neutron emission from the plasma, including background contributions. The reported results are of relevance for the development of compact neutron detectors with spectroscopy capabilities for installation in camera systems of present and future high power fusion experiments.

  18. High Density Deuterium Plasma

    International Nuclear Information System (INIS)

    A dense plasma focus or foci are formed beyond the end of the inner electrode of a coaxial electrode discharge as a result of a strong pinch effect (Z pinch). Previous magnetic field distribution measurements lead to this conclusion. The plasma has the following interesting properties: (1) an electron temperature (from soft X-ray intensity ratios), ∼2 to 5 keV; (2) plasma volume (from soft X-ray pinhole images), 1 to 5 mm3; (3) time duration, ∼0.2 to 0.3 μsec; and (4) neutron yields, ∼5 x 107 cm/sec. Neutron production scales almost linearly with energy up to ∼ 36 kj (neutron yields ∼1011); the larger energies require initial gas pressures up to ∼6 Torr due to larger j x B forces. It is a curious fact that the maximum average sheath velocity in the annulus is limited to 7 cm/sec. Recent measurements using a small dc Bz field in the region of the plasma focus show indeed that the radial collapsing current sheath efficiently traps and compresses this field onto the axis. An analysis of the breech voltage and di/dt signals shows the expected behaviour of the tube inductance with time. The optimum focusing action of the current sheath occurs at peak current time when most of the condenser energy is still in storage; this energy is rapidly converted into plasma energy by the pinch forces ia a time ∼0.1 μsec (average collapse velocity Vc ∼ 4 x 107 cm/sec). A best fit to the bremsstrahlung (Z = 1) and neutron (assuming a thermonuclear plasma) data yields a plasma density of ∼ 2 to 3 x 1019 cm-3. One concludes that under some conditions the density may finally reach ∼ 1020 cm3. A calculation based on a collision-dominated plasma, according to the Bennett pinch relation for Te = Ti = 5 keV, r ∼0.05 cm, n∼2 x 1019 cm-3 requires a current of ∼7 x 105 A; at 20 kV, peak currents are∼8 x 105 A. The product of calculated density n and time τ gives nτ = 6 x 1012 sec cm-3. The plasma lifetime τ is >>τ(hydromagnetic); a preliminary calculation

  19. Effect of surface oxide layer on deuterium permeation behaviors through a type 316 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Oya, Yasuhisa, E-mail: syoya@ipc.shizuoka.ac.jp [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Kobayashi, Makoto; Osuo, Junya; Suzuki, Masato; Hamada, Akiko; Matsuoka, Katsushi [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Hatano, Yuji; Matsuyama, Masao [Hydrogen Isotope Research Center, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan); Hayashi, Takumi; Yamanishi, Toshihiko [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Okuno, Kenji [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan)

    2012-08-15

    Effect of surface oxide layer on the hydrogen isotope permeation was studied. Iron oxide was uniformly formed in the oxide layer, although chromium was limited at the interface between the oxide layer and bulk SS-316. The permeation behavior of deuterium for oxidized SS-316 was compared with that for unoxidized SS-316 at temperature range of 333-673 K. The deuterium permeability for the oxidized SS-316 was reduced 1/10-1/20 times as high as that for unoxidized one. However, the activation energy of deuterium permeation as gas form for oxidized SS-316 was almost the same as that for unoxidized SS-316 and was 0.64 eV, which was almost consistent with the sum of activation energies for diffusion and solubility. This fact indicates that the deuterium permeation is diffusion limited. The permeability of deuterium as water form was almost constant even if heating temperature is high, showing that the deuterium was permeated through bulk SS-316 and react with oxygen at the oxide layer as water desorption, which is controlled by the permeation flux of deuterium and oxygen concentration on the surface of oxide layer in downstream side.

  20. Deuterium content variation of human blood serum

    International Nuclear Information System (INIS)

    We report, for the first time, the variation of deuterium content of blood serum of the patients with cancer disease. The tumorous cell, because of the higher growth speed , is deuterium consuming. The deuterium content of blood serum of cancerous human is diminished by about 5-7 ppm compared with that of the healthy individual. This effect is in accordance with some previous results. The replacement of tap water with deuterium depleted water in a drinking water of tumorous mice diminished the growth rate of tumors and the slight increase in the deuterium concentration stimulates growth because it is more easy for the cells to elevate the intracellular deuterium concentration up to the threshold level. (authors)

  1. Tissue Harmonic Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Joachim

    The main purpose of this PhD project is to develop an ultrasonic method for tissue harmonic synthetic aperture imaging. The motivation is to advance the field of synthetic aperture imaging in ultrasound, which has shown great potentials in the clinic. Suggestions for synthetic aperture tissue...... harmonic techniques have been made, but none of these methods have so far been applicable for in-vivo imaging. The basis of this project is a synthetic aperture technique known as synthetic aperture sequential beamforming (SASB). The technique utilizes a two step beamforming approach to drastically reduce...... system complexity compared to conventional synthetic aperture techniques. In this project, SASB is sought combined with a pulse inversion technique for 2nd harmonic tissue harmonic imaging. The advantages in tissue harmonic imaging (THI) are expected to further improve the image quality of SASB. The...

  2. Deuterium transport and trapping in aluminum alloys

    International Nuclear Information System (INIS)

    A simple model of diffusion and evolution of the density of deuterium in metals is presented. A model of the deuterium evolution in the presence of uniform and nonuniform distributions of traps, as well as perfectly reflecting and partially permeable boundary conditions is discussed. Computers are compared with experimental results describe deuterium distribution after fatigue crack growth of 2219 and 7075 aluminum alloys in a D2O water vapor environment and after ion implantation

  3. Cryogenic distillation facility for isotopic purification of protium and deuterium

    Science.gov (United States)

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kammel, P.; Kravtsov, P.; Petitjean, C.; Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M.

    2015-12-01

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  4. Cryogenic distillation facility for isotopic purification of protium and deuterium

    International Nuclear Information System (INIS)

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products

  5. Cryogenic distillation facility for isotopic purification of protium and deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, I.; Arkhipov, Ev.; Bondarenko, S.; Fedorchenko, O.; Ganzha, V.; Ivshin, K.; Kravtsov, P., E-mail: pkravt@gmail.com; Trofimov, V.; Vasilyev, A.; Vasyanina, T.; Vorobyov, A.; Vznuzdaev, M. [National Research Center “Kurchatov Institute” Petersburg Nuclear Physics Institute (NRC “Kurchatov Institute” PNPI), 188300 Gatchina (Russian Federation); Kammel, P. [Department of Physics, University of Washington, Seattle, Washington 98195 (United States); Petitjean, C. [Paul Scherrer Institut (PSI), CH-5232 Villigen (Switzerland)

    2015-12-15

    Isotopic purification of the protium and deuterium is an important requirement of many physics experiments. A cryogenic facility for high-efficiency separation of hydrogen isotopes with a cryogenic distillation column as the main element is described. The instrument is portable, so that it can be used at the experimental site. It was designed and built at the Petersburg Nuclear Physics Institute, Gatchina, Russia. Fundamental operating parameters have been measured including a liquid holdup in the column packing, the pressure drops across the column and the purity of the product at different operating modes. A mathematical model describes expected profiles of hydrogen isotope concentration along the distillation column. An analysis of ortho-parahydrogen isomeric composition by gas chromatography was used for evaluation of the column performance during the tuning operations. The protium content during deuterium purification (≤100 ppb) was measured using gas chromatography with accumulation of the protium in the distillation column. A high precision isotopic measurement at the Institute of Particle Physics, ETH-Zurich, Switzerland, provided an upper bound of the deuterium content in protium (≤6 ppb), which exceeds all commercially available products.

  6. Capabilities of nitrogen admixed cryogenic deuterium pellets

    Energy Technology Data Exchange (ETDEWEB)

    Sharov, Igor; Sergeev, Vladimir [SPU, Saint-Petersburg (Russian Federation); Lang, Peter; Ploeckl, Bernhard; Cavedon, Marco [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany); Kocsis, Gabor; Szepesi, Tamas [Wigner RCP RMI, Budapest (Hungary); Collaboration: ASDEX Upgrade Team

    2015-05-01

    Operation at high core density with high energy confinement - as foreseen in a future fusion reactor like DEMO - is being investigated at ASDEX Upgrade tokamak. The efficiency of pellet fuelling from the high-field side usually increases with increasing injection speed. Due to the fragile nature of the deuterium ice, however, the increment of pellet mass losses and subsequent pellet fragmentations take place when the speed is increased. Studies show, that admixing of a small amount of nitrogen (N{sub 2}) into D{sub 2} gas can be favorable for the mechanical stability of pellets. This might be helpful for deeper pellet penetration. Besides, seeding by N{sub 2} can enhance plasma performance due to both increasing the energy confinement time and reducing the divertor heat load in the envisaged ELMy H-mode plasma scenario. Fuelling efficiency of N{sub 2}-admixed solid D{sub 2} pellets and their nitrogen seeding capabilities were investigated. It was found that both the overall plasma density increase and the measured averaged pellet penetration depth were smaller in case of the admixed (1% mol. in the gas resulting in about 0.8% in the ice) pellet fuelling. Possibility of the N{sub 2}-seeding by admixed pellets was confirmed by CXRS measurements of N{sup 7+} content in plasma.

  7. Compounding in synthetic aperture imaging.

    Science.gov (United States)

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-09-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution and clutter levels are measured using a wire phantom setup and compared with conventional application of the array, as well as to synthetic aperture imaging without compounding. If the full aperture is used for synthetic aperture compounding, the cystic resolution is improved by 41% compared with conventional imaging, and is at least as good as what can be obtained using synthetic aperture imaging without compounding. PMID:23007781

  8. Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Nikolov, Svetoslav; Gammelmark, Kim Løkke;

    2006-01-01

    The paper describes the use of synthetic aperture (SA) imaging in medical ultrasound. SA imaging is a radical break with today's commercial systems, where the image is acquired sequentially one image line at a time. This puts a strict limit on the frame rate and the possibility of acquiring a...... SA imaging. Due to the complete data set, it is possible to have both dynamic transmit and receive focusing to improve contrast and resolution. It is also possible to improve penetration depth by employing codes during ultrasound transmission. Data sets for vector flow imaging can be acquired using...... short imaging sequences, whereby both the correct velocity magnitude and angle can be estimated. A number of examples of both phantom and in-vivo SA images will be presented measured by the experimental ultrasound scanner RASMUS to demonstrate the many benefits of SA imaging....

  9. Multiple Differential Aperture Microscopy

    International Nuclear Information System (INIS)

    Differential-aperture X-ray microscopy (DAXM) is a powerful approach to 3D tomography with particular relevance to X-ray microdiffraction. With DAXM, scattering from submicron volumes can be resolved. However, the method is intrinsically a scanning technique where every resolved volume element (voxel) requires at least one area-detector readout. Previous applications of DAXM have used a single wire for knife-edge step profiling. Here, we demonstrate a way to accelerate DAXM measurements using multiple wires. A proof-of-principle experiment with a three-wire prototype showed that the speed of measurements can be tripled, but careful calibrations of wires will be required to maintain the spatial accuracy. In addition, related possibilities for accelerating measurements are briefly discussed

  10. Stabilization of atomic hydrogen and deuterium

    International Nuclear Information System (INIS)

    This thesis deals with the first of a series of experiments done at the University of Amsterdam to study the properties of spin polarized atomic hydrogen (spa H) and deuterium (spa D) at very low temperatures (T approximately 0.3 K) and in high magnetic fields (B approximately 10 T). The experiments show that spa H and spa D may be subjected to experimental investigation like any normal (i.e. stable) gas. Chapter 2 deals with the experimental apparatus and in particular the development of a reliable method to cool atomic hydrogen to very low temperatures which turned out to be decisive for the experiments. An account of the first experiments with spa H can be found in chapter 3. These experiments showed that spa H can be stabilized for extended periods of time (at low temperature and in high magnetic fields) by covering all surfaces with a superfluid film of 4He. The gas was detected by triggering recombination by locally breaking the helium film and measuring the heat of recombination. This method turned out to be very sensitive and easy to implement. In chapter 4 the physical picture of the gas is discussed. This includes a discussion of the density profile and the phenomenon of thermal leakage from the open structured sample cell. The density profile may be used to detect Bose-Einstein condensation. A second series of experiments is discussed in chapter 5. These measurements were aimed at achieving high densities and to study the limiting processes. They demonstrate that spa H behaves as a gas. Recombination measurements with spa D at low temperatures are discussed in chapter 6 and show that recombination predominantly occurs on the surface of the helium film. (Auth.)

  11. Self characterization of a coded aperture array for neutron source imaging

    International Nuclear Information System (INIS)

    The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the stagnation stage of inertial confinement fusion implosions. Since the neutron source is small (∼100 μm) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-μm resolution are 20-cm long, triangular tapers machined in gold foils. These gold foils are stacked to form an array of 20 apertures for pinhole imaging and three apertures for penumbral imaging. These apertures must be precisely aligned to accurately place the field of view of each aperture at the design location, or the location of the field of view for each aperture must be measured. In this paper we present a new technique that has been developed for the measurement and characterization of the precise location of each aperture in the array. We present the detailed algorithms used for this characterization and the results of reconstructed sources from inertial confinement fusion implosion experiments at NIF

  12. Sequential Beamforming Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2013-01-01

    Synthetic aperture sequential beamforming (SASB) is a novel technique which allows to implement synthetic aperture beamforming on a system with a restricted complexity, and without storing RF-data. The objective is to improve lateral resolution and obtain a more depth independent resolution...

  13. Optimized baffle and aperture placement in neutral beamlines

    Science.gov (United States)

    Stone, R.; Duffy, T.; Vetrovec, J.

    1983-11-01

    Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. The beam losses are reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field is supplied by current coils without the iron poles. In addition, placement of the baffles and apertures affects the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. The placement of the baffles which, determine the amount of pumping in each chamber, and the apertures, which determine the beam loss were varied. A baffler/aperture configuration is for either minimum cold gas into the plasma region or minimum beam losses, but not both.

  14. Sparse synthetic aperture radar imaging with optimized azimuthal aperture

    Institute of Scientific and Technical Information of China (English)

    ZENG Cao; WANG MinHang; LIAO GuiSheng; ZHU ShengQi

    2012-01-01

    To counter the problem of acquiring and processing huge amounts of data for synthetic aperture radar (SAR) using traditional sampling techniques,a method for sparse SAR imaging with an optimized azimuthal aperture is presented.The equivalence of an azimuthal match filter and synthetic array beamforming is shown so that optimization of the azimuthal sparse aperture can be converted to optimization of synthetic array beamforming.The azimuthal sparse aperture,which is composed of a middle aperture and symmetrical bilateral apertures,can be obtained by optimization algorithms (density weighting and simulated annealing algorithms,respectively).Furthermore,sparse imaging of spectrum analysis SAR based on the optimized sparse aperture is achieved by padding zeros at null samplings and using a non-uniform Taylor window. Compared with traditional sampling,this method has the advantages of reducing the amount of sampling and alleviating the computational burden with acceptable image quality.Unlike periodic sparse sampling,the proposed method exhibits no image ghosts.The results obtained from airborne measurements demonstrate the effectiveness and superiority of the proposed method.

  15. The equation of state for the mixtures of dense hydrogen and deuterium

    International Nuclear Information System (INIS)

    The Hugoniot data and shock temperatures for the mixtures of dense hydrogen and deuterium were measured in the shock pressure range 75-140 MPa and temperature range 3400-3900 K by means of a two-stage light-gas gun and instantaneous optical pyrometer. The dense gas mixtures were shocked from environmental temperature and two initial pressures 0.6 and 1.2 MPa. Spectral radiance histories from the shocked mixtures of condensed hydrogen and deuterium were recorded by using a pyrometer. Shock wave velocity was measured and particle velocity was determined by the method of shock impedance matching. The data are discussed in terms of the Saha model

  16. Interferometric synthetic aperture microscopy

    Science.gov (United States)

    Ralston, Tyler S.; Marks, Daniel L.; Scott Carney, P.; Boppart, Stephen A.

    2007-02-01

    State-of-the-art methods in high-resolution three-dimensional optical microscopy require that the focus be scanned through the entire region of interest. However, an analysis of the physics of the light-sample interaction reveals that the Fourier-space coverage is independent of depth. Here we show that, by solving the inverse scattering problem for interference microscopy, computed reconstruction yields volumes with a resolution in all planes that is equivalent to the resolution achieved only at the focal plane for conventional high-resolution microscopy. In short, the entire illuminated volume has spatially invariant resolution, thus eliminating the compromise between resolution and depth of field. We describe and demonstrate a novel computational image-formation technique called interferometric synthetic aperture microscopy (ISAM). ISAM has the potential to broadly impact real-time three-dimensional microscopy and analysis in the fields of cell and tumour biology, as well as in clinical diagnosis where in vivo imaging is preferable to biopsy.

  17. Lucky imaging and aperture synthesis with low-redundancy apertures.

    Science.gov (United States)

    Ward, Jennifer E; Rhodes, William T; Sheridan, John T

    2009-01-01

    Lucky imaging, used with some success in astronomical and even horizontal-path imaging, relies on fleeting conditions of the atmosphere that allow momentary improvements in image quality, at least in portions of an image. Aperture synthesis allows a larger aperture and, thus, a higher-resolution imaging system to be synthesized through the superposition of image spatial-frequency components gathered by cooperative combinations of smaller subapertures. A combination of lucky imaging and aperture synthesis strengthens both methods for obtaining improved images through the turbulent atmosphere. We realize the lucky imaging condition appropriate for aperture synthesis imaging for a pair of rectangular subapertures and demonstrate that this condition occurs when the signal energy associated with bandpass spatial-frequency components achieves its maximum value. PMID:19107157

  18. Lucky imaging and aperture synthesis with low-redundancy apertures

    OpenAIRE

    Ward, Jennifer E.; Rhodes, William T.; Sheridan, John T.

    2009-01-01

    Lucky imaging, used with some success in astronomical and even horizontal-path imaging, relies on fleeting conditions of the atmosphere that allow momentary improvements in image quality, at least in portions of an image. Aperture synthesis allows a larger aperture and, thus, a higher-resolution imaging system to be synthesized through the superposition of image spatial-frequency components gathered by cooperative combinations of smaller subapertures. Acombination of lucky imaging and aper...

  19. Deuterium Retention and Microstructural Evolution of D2+ -Irradiated Stainless Steels

    International Nuclear Information System (INIS)

    Full text of publication follows: A variety of important characteristics associated with the interaction of hydrogen plasma with the metallic walls of fusion devices are either entirely due to, or at least strongly influenced by surface impurities and chemical composition. Understanding of the roles of additional elements in defect structure evolution and deuterium uptake is important for the design of fusion reactor materials. The influence of deuterium on material microstructure, deuterium trapping and release was investigated using transmission electron microscopy, thermal desorption spectrometry and the nuclear reactions D(3He,p)4He. Reemission, retention and evolution of depth distribution profiles of deuterium in stainless steels (06Kh18Ni10, 08Kh18Ni10Ti, 12Kh18Ni10Ti, the commercially available and modified 316L and Cr12Mn20W2V) were studied for 12 keV D2+ implantation up to 1.1019- 1.1022 D/m2 at room and 600 K temperatures followed by annealing from 290 to 1500 K. Changes in hardness were measured using Vickers hardness indentation. Total amount of retained deuterium in Kh18-Ni10 SS saturated for ion fluencies above 4.0.1021 D/m2 and maximum saturation level was 2.1021 D/m2. The radiation-induced dislocation microstructure had no well-defined influence on the deuterium trapping. The results of performed experiments provide evidence of hydrogen trapping at irradiation vacancies end their complexes. A behavior of the deuterium retention is influenced by the manufacturing process and the sample history of stainless steels. Certain thermo-mechanical treatments stimulate the nucleation of martensitic phase acting as an anomalous strong gas trap, so the retained deuterium desorbs mainly at around 1200 K. (authors)

  20. UAVSAR Phased Array Aperture

    Science.gov (United States)

    Chamberlain, Neil; Zawadzki, Mark; Sadowy, Greg; Oakes, Eric; Brown, Kyle; Hodges, Richard

    2009-01-01

    This paper describes the development of a patch antenna array for an L-band repeat-pass interferometric synthetic aperture radar (InSAR) instrument that is to be flown on an unmanned aerial vehicle (UAV). The antenna operates at a center frequency of 1.2575 GHz and with a bandwidth of 80 MHz, consistent with a number of radar instruments that JPL has previously flown. The antenna is designed to radiate orthogonal linear polarizations in order to facilitate fully-polarimetric measurements. Beam-pointing requirements for repeat-pass SAR interferometry necessitate electronic scanning in azimuth over a range of -20degrees in order to compensate for aircraft yaw. Beam-steering is accomplished by transmit/receive (T/R) modules and a beamforming network implemented in a stripline circuit board. This paper, while providing an overview of phased array architecture, focuses on the electromagnetic design of the antenna tiles and associated interconnects. An important aspect of the design of this antenna is that it has an amplitude taper of 10dB in the elevation direction. This is to reduce multipath reflections from the wing that would otherwise be detrimental to interferometric radar measurements. This taper is provided by coupling networks in the interconnect circuits as opposed to attenuating the output of the T/R modules. Details are given of material choices and fabrication techniques that meet the demanding environmental conditions that the antenna must operate in. Predicted array performance is reported in terms of co-polarized and crosspolarized far-field antenna patterns, and also in terms of active reflection coefficient.

  1. Calculation Method and Distribution Characteristics of Fracture Hydraulic Aperture from Field Experiments in Fractured Granite Area

    Science.gov (United States)

    Cao, Yang-Bing; Feng, Xia-Ting; Yan, E.-Chuan; Chen, Gang; Lü, Fei-fei; Ji, Hui-bin; Song, Kuang-Yin

    2016-05-01

    Knowledge of the fracture hydraulic aperture and its relation to the mechanical aperture and normal stress is urgently needed in engineering construction and analytical research at the engineering field scale. A new method based on the in situ borehole camera measurement and borehole water-pressure test is proposed for the calculation of the fracture hydraulic aperture. This method comprises six steps. The first step is to obtain the equivalent hydraulic conductivity of the test section from borehole water-pressure tests. The second step is a tentative calculation to obtain the qualitative relation between the reduction coefficient and the mechanical aperture obtained from borehole camera measurements. The third step is to choose the preliminary reduction coefficient for obtaining the initial hydraulic aperture. The remaining three steps are to optimize, using the genetic algorithm, the hydraulic apertures of fractures with high uncertainty. The method is then applied to a fractured granite engineering area whose purpose is the construction of an underground water-sealed storage cavern for liquefied petroleum gas. The probability distribution characteristics of the hydraulic aperture, the relationship between the hydraulic aperture and the mechanical aperture, the hydraulic aperture and the normal stress, and the differences between altered fractures and fresh fractures are all analyzed. Based on the effects of the engineering applications, the method is proved to be feasible and reliable. More importantly, the results of the hydraulic aperture obtained in this paper are different from those results elicited from laboratory tests, and the reasons are discussed in the paper.

  2. What is the Total Deuterium Abundance in the Local Galactic Disk?

    CERN Document Server

    Linsky, J L; Moos, H W; Jenkins, E B; Wood, B E; Oliveira, C; Blair, W P; Friedman, S D; Gry, C; Knauth, D; Kruk, J W; Lacour, S; Lehner, N; Redfield, S; Shull, J M; Sonneborn, G; Williger, G M; Linsky, Jeffrey L.; Draine, Bruce T.; Jenkins, Edward B.; Wood, Brian E.; Oliveira, Cristina; Blair, William P.; Friedman, Scott D.; Gry, Cecile; Knauth, David; Kruk, Jeffrey W.; Lacour, Sylvestre; Lehner, Nicolas; Redfield, Seth; Sonneborn, George; Williger, Gerard M.

    2006-01-01

    Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together with spectra from the Copernicus and IMAPS instruments, reveal an unexplained very wide range in the observed deuterium/hydrogen (D/H) ratios for interstellar gas in the Galactic disk beyond the Local Bubble. We argue that spatial variations in the depletion of deuterium onto dust grains can explain these local variations in the observed gas-phase D/H ratios. We present a variable deuterium depletion model that naturally explains the constant measured values of D/H inside the Local Bubble, the wide range of gas-phase D/H ratios observed in the intermediate regime (log N(H I} = 19.2-20.7), and the low gas-phase D/H ratios observed at larger hydrogen column densities. We consider empirical tests of the deuterium depletion hypothesis: (i) correlations of gas-phase D/H ratios with depletions of the refractory metals iron and silicon, and (ii) correlation with the molecular hydrogen rotational temperature. Both ...

  3. Compounding in synthetic aperture imaging

    DEFF Research Database (Denmark)

    Hansen, J. M.; Jensen, J. A.

    2012-01-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic...... from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from...... tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance...

  4. Optimizing Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-01-01

    Spatial compound images are constructed from synthetic aperture data acquired using a linear phased-array transducer. Compound images of wires, tissue, and cysts are created using a method, which allows both transmit and receive compounding without any loss in temporal resolution. Similarly to...... optimal for lesion detection. Synthetic aperture data are acquired from unfocused emissions and 154 compound images are constructed by synthesizing different aperture configurations with more or less compounding, all maintaining a constant resolution across depth corresponding to an f-number of 2.0 for...... transmit and receive. The same configurations are used for scanning a phantom with cysts, and it is demonstrated how an improved cysts contrast follows from an aperture configuration, which gives a higher value for the performance measure extracted from the phantom without cysts. A correlation value R = 0...

  5. Synthetic Aperture Radar - Hardware Development

    OpenAIRE

    Rosner, V.; Seller, R.; L. Dudas; Kazi, K.; Miko, G.

    2009-01-01

    Experimental real and synthetic aperture radar are developed from the base-band digital unit to the analogue RF parts, based on solid state units, using pulse compression for radar imaging. Proper QPSK code is found for matched filter.

  6. Synthetic aperture controlled source electromagnetics

    OpenAIRE

    Fan, Y.; Snieder, R.; Slob, E.; Hunziker, J.W.; Singer, J.; Sheiman, J.; Rosenquist, M.

    2010-01-01

    Controlled‐source electromagnetics (CSEM) has been used as a de‐risking tool in the hydrocarbon exploration industry. Although there have been successful applications of CSEM, this technique is still not widely used in the industry because the limited types of hydrocarbon reservoirs CSEM can detect. In this paper, we apply the concept of synthetic aperture to CSEM data. Synthetic aperture allows us to design sources with specific radiation patterns for different purposes. The ability to detec...

  7. Fusion product diagnostics planned for Large Helical Device deuterium experiment

    International Nuclear Information System (INIS)

    Deuterium experiment on the Large Helical Device (LHD) is now being planned at the National Institute for Fusion Science. The fusion product diagnostics systems currently considered for installation on LHD are described in this paper. The systems will include a time-resolved neutron yield monitor based on neutron gas counters, a time-integrated neutron yield monitor based on activation techniques, a multicollimator scintillation detector array for diagnosing spatial distribution of neutron emission rate, 2.5 MeV neutron spectrometer, 14 MeV neutron counter, and prompt γ-ray diagnostics.

  8. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core

    OpenAIRE

    Sándor B. Ötvös; Chi-Ting Hsieh; Yang-Chang Wu; Jih-Heng Li; Fang-Rong Chang; Ferenc Fülöp

    2016-01-01

    Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological ef...

  9. Deuterium inventory in Tore Supra: Contribution of carbon deposits outgassing

    Energy Technology Data Exchange (ETDEWEB)

    Panayotis, S., E-mail: stephanie.panayotis@cea.fr [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Pégourié, B.; Caprin, E.; Douai, D.; Hatchressian, J.-C.; Negrier, V.; Pascal, J.-Y.; Vartanian, S.; Bucalossi, J.; Monier-Garbet, P. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2013-07-15

    In carbon dominated devices, the in vessel D inventory obtained from post-mortem analyses of plasma facing component samples is generally smaller by a factor of ∼4 than that estimated from gas balance measurements. However, for an accurate evaluation of the wall inventory, gas balance measurements must be done not only during discharges and conditioning procedures, but also in between discharges and during vents. From the analysis of the whole Tore Supra database for the 2002–2007 period, we show that long term outgassing during nights, weekends and vents is essential for evaluating the deuterium release. Taking these contributions into account reconciles the gas balance and post-mortem estimations of fuel retention.

  10. Deuterium inventory in Tore Supra: Contribution of carbon deposits outgassing

    International Nuclear Information System (INIS)

    In carbon dominated devices, the in vessel D inventory obtained from post-mortem analyses of plasma facing component samples is generally smaller by a factor of ∼4 than that estimated from gas balance measurements. However, for an accurate evaluation of the wall inventory, gas balance measurements must be done not only during discharges and conditioning procedures, but also in between discharges and during vents. From the analysis of the whole Tore Supra database for the 2002–2007 period, we show that long term outgassing during nights, weekends and vents is essential for evaluating the deuterium release. Taking these contributions into account reconciles the gas balance and post-mortem estimations of fuel retention

  11. Energy Levels of Hydrogen and Deuterium

    Science.gov (United States)

    SRD 142 Energy Levels of Hydrogen and Deuterium (Web, free access)   This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.

  12. The phases of deuterium at extreme densities

    OpenAIRE

    Bedaque, Paulo F.; Buchoff, Michael I.; Cherman, Aleksey

    2010-01-01

    We consider deuterium compressed to higher than atomic, but lower than nuclear densities. At such densities deuterium is a superconducting quantum liquid. Generically, two superconducting phases compete, a "ferromagnetic" and a "nematic" one. We provide a power counting argument suggesting that the dominant interactions in the deuteron liquid are perturbative (but screened) Coulomb interactions. At very high densities the ground state is determined by very small nuclear interaction effects th...

  13. NPS high resolution synthetic aperture sonar

    OpenAIRE

    Welter, Joseph Donald

    1995-01-01

    This thesis investigated the use of synthetic aperture techniques to achieve a long effective aperture, high resolution, imaging sonar. The approach included a full simulation of the system using the MATLAB programming environment that provided a model for developing six data processing algorithms and a working 25KHz, 1 m baseline, air medium synthetic aperture sonar. The six azimuthal processing techniques included: (1) a normal, real aperture, (2) an unfocussed synthetic aperture, (3) a hyb...

  14. Temperature dependence of blistering and deuterium retention in tungsten

    International Nuclear Information System (INIS)

    Tungsten has been selected as the plasma facing material (PFM) at the divertor baffles and dome in the ITER design, because tungsten has a very high threshold energy for sputtering, a high melting point and a very low tritium inventory. However, blistering can occur at tungsten surface, even if the ion energy is too low to create displacement damage such as vacancies. Tungsten blistering could lead to instability of the plasma due to high-Z impurity release into the core plasma and sudden gas recycling. In addition, an increasing tritium inventory in the near surface region of PFCs could become a significant safety issue during the exchange process of the PFCs. Therefore, blistering and deuterium retention in tungsten exposed to high fluences (up to 1E27 D/m2) of high flux (1E22 D+/m2/s) and low energy (38 eV) deuterium plasma were examined in the temperature range of 315 K to 1000 K with scanning electron microscopy (SEM), focused ion beam (FIB) and thermal desorption spectroscopy (TDS). At 315 K, only sparse low-dome blisters with a chord of a few microns or less appeared even the fluence was increased to 1E27 D/m2. At around 400 K, the blisters became much denser and the dome of blisters became a little higher. Peculiar change occurred around 500 K, where two kinds of blisters appeared. One is the large blisters with sizes of a few tens of microns and varying ratios of height against chord (up to 0.6), and the other is the small blisters with chords of less than a few microns and large ratio of height against chord (about 0.7). In high temperature region (higher than 600 K), the blisters became much sparser with the increasing temperature and disappeared at 1000 K. In addition, the phenomenon of blister bursting with a tail, or partially-opened or fully-opened lid was found on some grains after plasma exposure or TDS experiments. During TDS experiments, bursting release with sadden peaks was observed, suggesting the bursts of blisters. Deuterium retention showed

  15. Deuterium contents in animal organisms in presence of natural abundance and depleted deuterium aqueous media

    International Nuclear Information System (INIS)

    Deuterium,the stable heavy isotope of hydrogen, when more abundant than the natural values (i.e. 144 ppm), as in heavy water, induces significant alterations in the anatomy and physiology of animal or vegetal cells. Such alterations eventually entail the death of the cell. On the other hand some products with depleted deuterium have antagonistic effects due to deuterium removal from the cells. The paper reports results of measurements of deuterium concentration in various biological samples in studies about distribution of deuterium depleted agents in organisms. The biological samples studied came from a lot of individuals fed in a regime of depleted deuterium. The mass spectrometric analyses of these biological samples showed that dispersion of deuterium depleted agents inside the organisms is determined by several endo- and exogenous factors. The paper describes the specific procedures of sampling the biological materials destined to isotopic analyses, the extraction of water in vacuum, the methods of deuterium concentration determination and finally presents a discussion of the results reported

  16. Fluence dependence of deuterium retention in oxidized SS-316

    Science.gov (United States)

    Oya, Yasuhisa; Suzuki, Sachiko; Matsuyama, Masao; Hayashi, Takumi; Yamanishi, Toshihiko; Asakura, Yamato; Okuno, Kenji

    2011-10-01

    The ion fluence dependence of deuterium retention in SS-316 during oxidation at a temperature of 673 K was studied to evaluate the dynamics of deuterium retention in the oxide layer of SS-316. The correlation between the chemical state of stainless steel and deuterium retention was evaluated using XPS and TDS. It was found that the major deuterium desorption temperatures were located at around 660 K and 935 K, which correspond to the desorption of deuterium trapped as hydroxide. The deuterium retention increased with increasing deuterium ion fluence, since the deuterium retention as hydroxide increased significantly. However, retention saturated at an ion fluence of ˜2.5 × 10 21 D + m -2. The XPS result showed that FeOOD was formed on the surface, although pure Fe also remained in the oxide layer. These facts indicate the nature of the oxide layer have a key role in deuterium trapping behavior.

  17. Deuterium enrichment of interstellar dusts

    Science.gov (United States)

    Das, Ankan; Chakrabarti, Sandip Kumar; Majumdar, Liton; Sahu, Dipen

    2016-07-01

    High abundance of some abundant and simple interstellar species could be explained by considering the chemistry that occurs on interstellar dusts. Because of its simplicity, the rate equation method is widely used to study the surface chemistry. However, because the recombination efficiency for the formation of any surface species is highly dependent on various physical and chemical parameters, the Monte Carlo method is best suited for addressing the randomness of the processes. We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantle under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C, CH_3, CH_2D, OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ˜2 × 10^4 cm^{-3}), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (˜10^6 cm^{-3}), water and methanol productions are suppressed but surface coverage of CO, CO_2, O_2, O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high fractionation of methanol but surprisingly water fractionation is found to be low. This is in contradiction with our model results indicating alternative routes for de-fractionation of water.

  18. A flat laser array aperture

    Science.gov (United States)

    Papadakis, Stergios J.; Ricciardi, Gerald F.; Gross, Michael C.; Krill, Jerry A.

    2010-04-01

    We describe a design concept for a flat (or conformal) thin-plate laser phased-array aperture. The aperture consists of a substrate supporting a grid of single-mode optical waveguides fabricated from a linear electro-optic material. The waveguides are coupled to a single laser source or detector. An arrangement of electrodes provides for two-dimensional beam steering by controlling the phase of the light entering the grid. The electrodes can also be modulated to simultaneously provide atmospheric turbulence modulation for long-range free-space optical communication. An approach for fabrication is also outlined.

  19. High resolution non-iterative aperture synthesis.

    Science.gov (United States)

    Kraczek, Jeffrey R; McManamon, Paul F; Watson, Edward A

    2016-03-21

    The maximum resolution of a multiple-input multiple-output (MIMO) imaging system is determined by the size of the synthetic aperture. The synthetic aperture is determined by a coordinate shift using the relative positions of the illuminators and receive apertures. Previous methods have shown non-iterative phasing for multiple illuminators with a single receive aperture for intra-aperture synthesis. This work shows non-iterative phasing with both multiple illuminators and multiple receive apertures for inter-aperture synthesis. Simulated results show that piston, tip, and tilt can be calculated using inter-aperture phasing after intra-aperture phasing has been performed. Use of a fourth illuminator for increased resolution is shown. The modulation transfer function (MTF) is used to quantitatively judge increased resolution. PMID:27136816

  20. Validation of the deuterium oxide method for measuring average daily milk intake in infants

    International Nuclear Information System (INIS)

    The deuterium oxide elimination method for measuring average daily milk intake was validated against measured formula intake in 16 studies of 11 infants in a metabolic ward. Deuterium oxide (approximately 0.10 g/kg body wt) was given orally. Deuterium enrichment was measured in urine samples collected predose, as available for 6-h postdose for TBW determination, and at 24 h and 5-10 d postdose for HDO elimination calculated according to the two-point method. Urine samples were vacuum distilled, water was reduced to hydrogen gas, and deuterium enrichment was measured by isotope-ratio mass spectrometry. Milk intake was measured throughout the elimination period from prefeeding and postfeeding bottle weights (n = 12) or volumes (n = 4). Without corrections for atmospheric water influx, milk intake was overestimated by 76 g/d (6%). With corrections for estimated metabolic water production, isotopic fractionation, and atmospheric water influx, deuterium measured 98% +/- 3% or 1300 g milk intake/d compared with actual milk intake of 1329 +/- 206 g/d

  1. Deuterium absorption and material phase characteristics of SAES St 198 Zr-Fe Alloy

    International Nuclear Information System (INIS)

    This document reports deuterium absorption and material phase characteristics of SAES St 198 Zr-Fe Alloy (76.5% Zr). Scanning electron microscope images of polished surfaces, electron probe microanalysis, and x-ray powder diffractometry indicated the presence of a primary Zr2Fe phase with secondary phases of ZrFe2, Zr5FeSn, α-Zr, and Zr6Fe3O. A statistically designed experiment to determine the effects of temperature, time, and vacuum quality on activation of St 198 revealed that, when activated at low temperature (350C), deuterium absorption rate was slower when the vacuum quality was poor (2.5 Pa vs. 3 x 10-4 Pa). However, at higher activation temperature (500C), deuterium absorption rate was fast and was independent of vacuum quality. Deuterium pressure-composition-temperature (P-C-T) data are reported for St 198 in the temperature range 200 to 500C. The P-C-T data over the full range of deuterium loading and at temperatures of 350C and below is described an expression. At higher temperatures, one or more secondary reactions in the solid phase occur that slowly consume D2 from the gas phase. X-ray diffraction and other data suggest these reactions to be: 2 Zr2FeDx → xZrD2 + x/3 ZrFe2 + (2 - 2/3x) Zr2Fe and Zr2FeDx + (2 - 1/2x) D2 → 2 ZrD2 + Fe, where 0 2Fe formed in the first reaction accounts for the observed consumption of deuterium from the gas phase by this reaction

  2. In situ accelerator analysis of palladium complex under deuterium permeation

    International Nuclear Information System (INIS)

    Preliminary results of experiments on D2 gas permeation using a system (vacuum/CaO/Sr/PdDx/D2) have shown some evidence of nuclear transmutation from Sr to Mo. The system is a little simpler than that used by Imamura et al., and has a reversed gas flow direction. The diagnostic method used to identify the elements was conventional X-ray photoelectron spectroscopy, giving the areal densities of 4.2x1014 cm-2 (Sr) and 3.3x1014 cm-2 (Mo). Extended analytical methods are now being prepared, including in situ and simultaneous particle induced X-ray emission, Rutherford backscattering spectroscopy, nuclear reaction analysis, and elastic recoil detection analyse for areal densities of transmutation elements and deuterium distribution. (author)

  3. Ultrasound fields from triangular apertures

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1996-01-01

    The pulsed field from a triangular aperture mounted in an infinite, rigidbaffle is calculated. The approach of spatial impulse responses,as developed by Tupholme and Stepanishen, is used. By this both the emitted and received pulsed ultrasound field can be found for any transducerexcitation and...

  4. Synthetic Aperture Radar - Hardware Development

    Directory of Open Access Journals (Sweden)

    V. Rosner

    2009-06-01

    Full Text Available Experimental real and synthetic aperture radar are developed from the base-band digital unit to the analogue RF parts, based on solid state units, using pulse compression for radar imaging. Proper QPSK code is found for matched filter.

  5. Capillarity and dielectrophoresis of liquid deuterium

    International Nuclear Information System (INIS)

    The ponderomotive force, exerted upon all dielectric liquids by a non-uniform electric field, can be used for the remote, voltage-controlled manipulation of 10 to 100 μL volumes of cryogenic liquids. This liquid dielectrophoretic (DEP) effect, imposed by specially designed electrodes, combines with capillarity to influence the hydrostatic equilibria of liquid deuterium. A simple, one-dimensional model accurately predicts the measured meniscus rise of D2 against gravity for sufficiently wide, parallel electrodes. For narrow electrodes, where the sidewalls influence the equilibrium, a finite element solution using the Surface Evolver software correctly describes the shape of the meniscus. A bifurcation phenomenon previously observed for room temperature dielectrics is also observed in liquid deuterium. Cryo-DEP actuation has potential applications ranging from metering precise volumes of liquid deuterium for laser target fuelling to manipulation of liquid nitrogen for cryo-preservation of biological samples.

  6. Capillarity and dielectrophoresis of liquid deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T B [Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY 14627 (United States); Gram, R; Harding, D R [Laboratory for Laser Energetics, University of Rochester, Rochester, NY 14627 (United States); Kentch, K, E-mail: jones@ece.rochester.ed [Department of Biomedical Engineering, University of Rochester, Rochester, NY 14627 (United States)

    2009-11-21

    The ponderomotive force, exerted upon all dielectric liquids by a non-uniform electric field, can be used for the remote, voltage-controlled manipulation of 10 to 100 {mu}L volumes of cryogenic liquids. This liquid dielectrophoretic (DEP) effect, imposed by specially designed electrodes, combines with capillarity to influence the hydrostatic equilibria of liquid deuterium. A simple, one-dimensional model accurately predicts the measured meniscus rise of D{sub 2} against gravity for sufficiently wide, parallel electrodes. For narrow electrodes, where the sidewalls influence the equilibrium, a finite element solution using the Surface Evolver software correctly describes the shape of the meniscus. A bifurcation phenomenon previously observed for room temperature dielectrics is also observed in liquid deuterium. Cryo-DEP actuation has potential applications ranging from metering precise volumes of liquid deuterium for laser target fuelling to manipulation of liquid nitrogen for cryo-preservation of biological samples.

  7. Deuterium NMR, induced and intrinsic cholesteric lyomesophases

    International Nuclear Information System (INIS)

    Induced and intrinsic cholesteric lyotropic mesophases were studied. Induced cholesteric lyomesophases based on potassium laurate (KL) system, with small amounts of cholesterol added, were studied by deuterium NMR and by polarizing microscopy. Order profiles obtained from deuterium NMR of KL perdenderated chains in both induced cholesteric and normal mesophases were compared. The intrinsic cholesteric lyotropic mesophases were based on the amphiphile potassium N-lauroyl serinate (KLNS) in the resolved levo form. The study of the type I intrinsic cholesteric mesophase was made by optical microscopy under polarized light and the type II intrinsic cholesteric lyomesophase was characterized by deuterium NMR. The new texture was explained by the use of the theory of disclinations developed for thermotropic liquid crystals, specially for cholesteric type. (M.J.C.)

  8. Neutrino and Antineutrino Interactions in Deuterium

    CERN Multimedia

    2002-01-01

    This experiment uses BEBC filled with deuterium and exposed to the wide-band neutrino beam N1. The use of deuterium as the target material allows to study interactions on both neutrons and protons. The charge of the target nucleon can be inferred from the number of positive and negative particles in the final state. \\\\ \\\\ Some of the physics aims of this experiment are to measure separately the cross sections @s^n and @s^p on neutrons and protons to determine the structure functions F|n(x,Q|2) and F|p(x,Q|2), the fragmentation functions D(z,Q|2) and the ratio of neutral to charged current interactions. \\\\ \\\\ Additional problems under investigation are the production of nucleon isobars, and of resonances in general, the production of strange and of charmed particles, and the problems of deuterium structure.

  9. Deuterium production by cosmological cosmic rays

    International Nuclear Information System (INIS)

    Among the various low-energy interactions that take place at high redshifts (z approximately 100) between a (hypothetical) flux of cosmological cosmic rays (''CCR'': protons and α particles), and the ambient gaseous medium, deuterium production is interesting in view of the relevance of this element to big-bang cosmology. The production cross-sections are discussed in detail. The abundance of deuterium produced by this process is computed by normalizing the CCR flux so as to account for the approximately 1-100 MeV γ-ray background spectrum. The resulting D (and 3He) abundances may reach approximately 20% of their observed value. It is also shown how the results can be compared with those obtained recently by Epstein et al. on deuterium production by ''pregalactic cosmic rays''. (author)

  10. Deuterium-incorporated gate oxide of MOS devices fabricated by using deuterium ion implantation

    International Nuclear Information System (INIS)

    In the aspect of metal-oxide-semiconductor (MOS) device reliability, deuterium-incorporated gate oxide could be utilized to suppress the wear-out that is combined with oxide trap generation. An alternative deuterium process for the passivation of oxide traps or defects in the gate oxide of MOS devices has been suggested in this study. The deuterium ion is delivered to the location where the gate oxide resides by using an implantation process and subsequent N2 annealing process at the back-end of metallization process. A conventional MOS field-effect transistor (MOSFET) with a 3-nm-thick gate oxide and poly-to-ploy capacitor sandwiched with 20-nm-thick SiO2 were fabricated in order to demonstrate the deuterium effect in our process. An optimum condition of ion implantation was necessary to account for the topography of the overlaying layers in the device structure and to minimize the physical damage due to the energy of the implanted ion. Device parameter variations, the gate leakage current, and the dielectric breakdown phenomenon were investigated in the deuterium-ion-implanted devices. We found the isotope effect between hydrogen- and deuterium-implanted devices and an improved electrical reliability in the deuterated gate oxide. This implies that deuterium bonds are generated effectively at the Si/SiO2 interface and in the SiO2 bulk.

  11. Cold neutron scattering in imperfect deuterium crystals

    CERN Document Server

    Adamczak, Andrzej

    2010-01-01

    The differential cross sections for cold neutron scattering in mosaic deuterium crystals have been calculated for various target temperatures. The theoretical results are compared with the recent experimental data for the neutron wavelengths $\\lambda\\approx$~1--9~\\AA. It is shown that the structures of observed Bragg peaks can be explained by the mosaic spread of about $3^{\\circ}$ and contributions from a~limited number of crystal orientations. Such a~crystal structure should be also taken into account in ultracold neutron upscattering due to the coherent phonon annihilation in solid deuterium.

  12. Continuum emission from irradiated solid deuterium

    DEFF Research Database (Denmark)

    Forrest, J.A.; Brooks, R.L.; Hunt, J.L.; Stenum, B.; Schou, Jørgen; Sørensen, H.; Gürtler, P.; Magnotta, F.; Mapoles, E.R.; Souers, P.C.; Collins, G.W.

    1992-01-01

    A new emission feature from the spectrum of irradiated solid deuterium has been observed in the very near-infrared spectral region. Experiments from three laboratories, using different excitation conditions, have confirmed the observation. Comparison of the timing and temperature dependence of the...... spectral feature to the information previously available from electron spin resonance studies of solid deuterium, points to atomic association as the underlying cause. We shall show the connection of this emission to the occurrence of thermal spikes and optical flashes, previously observed in solid...

  13. Monte Carlo simulation for Kaonic deuterium studies

    International Nuclear Information System (INIS)

    Full text: The SIDDHARTA experiment at the DAFNE collider measured the shift and with of the ground level in kaonic hydrogen caused by the strong interaction between the kaons and protons. The measurement of the X-ray transitions to the 1s level in kaonic deuterium will allow, together with the available results from kaonic hydrogen, to extract the isospin- dependent antikaon-nucleon scattering lengths. I will present the Monte Carlo simulation of the SIDDHARTA-2 setup, in the framework of GEANT4. The program is used to optimize the critical parameters of the setup in order to perform the kaonic deuterium measurement. (author)

  14. Recent findings on blistering and deuterium retention in tungsten exposed to high-fluence deuterium plasma

    International Nuclear Information System (INIS)

    Blistering and deuterium retention in tungsten exposed to high-fluence (up to 1027 D/m2) of high-flux (1022 D+/m2/s) and low-energy (38 eV) deuterium plasma were examined in the temperature range of 315-1000 K with scanning electron microscopy, focused ion beam, thermal desorption spectroscopy and positron annihilation. There were cavities inside small blisters with the maximum ratio of height against diameter of about 0.7, whereas there were voids/holes along the grain boundary beneath most large blisters but no hollow lid formed. Blistering and deuterium retention showed a significant dependence upon fluence and exposure temperature.

  15. Influence of deuterium on the design of the JET water detritiation system

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, I. [Forschungszentrum Karlsruhe, TLK, P.O. Box 3640, 76021 Karlsruhe (Germany)]. E-mail: ion.cristescu@hvt.fzk.de; Cristescu, I.-R. [Forschungszentrum Karlsruhe, TLK, P.O. Box 3640, 76021 Karlsruhe (Germany); Doerr, L. [Forschungszentrum Karlsruhe, TLK, P.O. Box 3640, 76021 Karlsruhe (Germany); Glugla, M. [Forschungszentrum Karlsruhe, TLK, P.O. Box 3640, 76021 Karlsruhe (Germany); Bell, A. [JET, UKAEA, Culham Science Center, Abigdon, Oxon OX14 3DB (United Kingdom); Brennan, D. [JET, UKAEA, Culham Science Center, Abigdon, Oxon OX14 3DB (United Kingdom); Murdoch, D. [EFDA-CSU Boltzmannstrasse 2, D-85748 Garching (Germany)

    2005-11-15

    The water detritiation system (WDS) for JET is based on the combined electrolysis catalytic exchange (CECE) process employing a liquid phase catalytic exchange (LPCE) column. The final goal of WDS is to convert tritiated water to tritium-deuterium-hydrogen mixture for further enrichment of tritium by cryogenic distillation (CD), followed by recovery of high quality tritium in the gas chromatography (GC) from active gas handling system (AGHS) of JET. A tritium decontamination factor (DF) of 10{sup 4} is required along the striping section of the LPCE column in order to discharge essentially tritium free molecular hydrogen product into the environment. A detailed analysis of the combination CECE-CD processes revealed the necessity to consider also the deuterium content in the water to be processed. Based on deuterium content measured in tritiated water collected at JET, the interface between the CECE and CD was evaluated in detail and the optimum values for deuterium and tritium composition at this interface have been established.

  16. Measurement of anomalous neutron from deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings are designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting is used for electrolysis experiments. No neutron counting rate statistically higher than detection limit is observed from Fleischmann and Pons type experiments. An HLNCC-II neutron detector equipped with 18 3He tubes and a JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run are employed to study the neutron signals in D2 gas experiments. Ten batches of dry fusion samples are tested, among them, seven batches with neutron burst signals occur roughly at the temperature from -100 degrees centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts are observed with neutron numbers from 15 to 482,which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in between and afterwards and for sample batch after certain runs

  17. Measurement of anomalous neutron from deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings are designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting is used for electrolysis experiments. No neutron counting rate statistically higher than detection limit is observed from Fleischmann and Pons type experiments. An HLNCC-II neutron detector equipped with 18 3He tubes and JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run are employed to study the neutron signals in D2 gas experiments. Ten batches of dry fusion samples are tested, among them, seven batches with neutron burst signals occur roughly at the temperature from -100 degrees centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts are observed with neutron numbers from 15 to 482, which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in-between and afterwards and for sample batch after certain runs

  18. Evidence for hydrogen-deuterium exchange in viral particles

    Institute of Scientific and Technical Information of China (English)

    MAO Jiangsen; LIU Ziyang; TANG Caihua; HE Yihui; ZHU Jiahong; WANG Chengyu; CHAI Shaoai; CHEN Yueqing; QIAN Wen

    2004-01-01

    Heavy water (D2O) could enhance thermostability of some viruses. However, the underlying mechanism is not clear. Here we report the development of a matrix-aided gas-isotope-ratio mass spectrometry method that allows direct determination of deuterium/hydrogen (D/H) ratio in D2O-treated Japanese encephalitis virus (JEV), hepatitis A virus (HAV) and RNA from D2O-treated HAV. The D/H ratio was expressed as δDSMOW. Our experiments showed that δDSMOW values increased significantly in D2O-treated viral samples compared to normal controls, and increment in δDSMOW of D2O, treated viral samples was in a fine linear relationship with increment in amount of samples loaded in BSA matrix. Our experiments also indicated that increased δDSMOW of D2O-treated virus correlated well with its enhanced thermostability. The results suggested that hydrogen-deuterium exchange occurred in viral particles and its RNA structure as a result of D2O-treatment. Furthermore, such exchange could cause changes in viral phenotype, such as enhanced thermostability.

  19. A High Deuterium Abundance at z=0.7

    CERN Document Server

    Webb, J K; Lanzetta, K M; Ferlet, R; Lemoine, M; Vidal-Madjar, A; Bowen, D V

    1997-01-01

    Of the light elements, the primordial abundance of deuterium, (D/H)_p, provides the most sensitive diagnostic for the cosmological mass density parameter Omega_B. Recent high redshift (D/H) measurements are highly discrepant, although this may reflect observational uncertainties. The larger (D/H) values, which imply a low Omega_B and require the Universe to be dominated by non-baryonic matter (dynamical studies indicate a higher total density parameter), cause problems for galactic chemical evolution models since they have difficulty in reproducing the large decline down to the lower present-day (D/H). Conversely, low (D/H) values imply an Omega_B greater than derived from ^7Li and ^4He abundance measurements, and may require a deuterium abundance evolution that is too low to easily explain. Here we report the first measurement at intermediate redshift, where the observational difficulties are smaller, of a gas cloud with ideal characteristics for this experiment. Our analysis of the z = 0.7010 absorber towar...

  20. High density polarized hydrogen/deuterium internal target

    CERN Document Server

    Van Buuren, L D; Van der Brand, J F J; Bulten, H J; Ferro-Luzzi, M; Kolster, H; Lang, J; Simani, M C; Mul, F

    2000-01-01

    We present a high-density polarized hydrogen/deuterium internal gas target. The apparatus is based on a setup that was previously used in electron scattering experiments with tensor-polarized deuterium [1]. The target was upgraded by implementing state-of-the-art permanent sextupole magnets in the Atomic Beam Source (ABS) and by using a longer (60 cm) and colder (approx 70 K) cylindrical storage cell. This resulted in an increase of the target figure-of-merit, (polarization) sup 2 x luminosity, by about one order of magnitude. The target was used in combination with a 720 MeV polarized electron beam stored in the AmPS ring (NIKHEF) to measure spin observables in electron-proton and electron-deuteron scattering. Scattered electrons were detected in a large acceptance magnetic spectrometer. Ejected hadrons were detected in a single time-of-flight scintillator array. The product of beam and target polarization was determined from the known e'p (quasi) elastic asymmetry. We achieved a target thickness of 1.1 x 10...

  1. Scintiscanning with a coded aperture

    International Nuclear Information System (INIS)

    In scintigraphy the quality of the recorded image is a function of the quantum statistics of the photons, because only a small number of photons are available for an image. If the apertured or parallel-hole collimator is replaced by a coded aperture, e.g., a Fresnel-type zone plate of the proper size, a much larger fraction of the gamma quanta emitted by the object under investigation are captured, and there is no loss in resolution. A technique is described which allows the sequential reconstruction of various planes of the object while, at the same time, eliminating the spurious constant light fraction. For recording of the incoherent gamma hologram an on-axis zone plate can be used. In the coherent-optical reconstruction the gamma hologram is correlated with the zone plate used for the recording process. The experimental results shown are optical reconstructions of phantoms filled with 57Co. (orig./ORU)

  2. Airborne synthetic aperture acoustic imaging.

    Science.gov (United States)

    Soumekh, M

    1997-01-01

    This paper presents a system model and inversion for airborne synthetic aperture acoustic (SAA) imaging. The system model accurately represents the intercation of the acoustic source and the target region at near range values. Moreover, the model incorporates the fact that the relative speed of the vehicle's (transmitter/receiver) with respect to the target region is comparable to the acoustic wave propagation speed. The inversion utilizes the principle of spectral decomposition of spherical phase functions to develop a wavefront reconstruction method from SAA data. Processing issues and selection of appropriate acoustic FM-CW sources are discussed. Results are provided that exhibit the superior accuracy of the proposed SAA system model and inversion over their synthetic aperture radar (SAR) counterpart in which the vehicle's speed is assumed to be much smaller than the wave propagation speed. PMID:18282912

  3. The study on aperture configuration of optical synthetic aperture imaging system

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A model based on Fourier domain consideration on aperture configuration of optical synthetic aperture imaging system is introduced in this paper. The derivation of the model is directly linked to the restoration error of the original object from the recorded image. The aperture configuration is a function of the maximum frequency of interest, and takes into account the diameter of the aperture. The simulative results of genetic algorithms illustrate the usefulness of this model for designing a synthetic aperture optical imaging system, and the aperture configuration of a good synthetic aperture optical imaging system should be non-redundant.

  4. Photochemical deuterium separation: problems and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Marling, J.B.; Herman, I.P.

    1978-09-01

    Photochemical separation of deuterium is examined to determine if either an ultraviolet or an infrared laser-based technology offers greater promise for development into an industrially viable heavy water production process. The three systems to be discussed are multiple-photon dissociation of organic molecules by pulsed CO/sub 2/ laser; CO or CO/sub 2/ laser-induced bimolecular reactions; and single-photon induced molecular dissociation by ultraviolet laser. Multiple-photon dissociation by CO/sub 2/ laser is attractive, since it utilizes an already developed high-power and efficient laser technology. Furthermore, single-step deuterium enrichment factors exceeding 1000-fold have been observed in the CF/sub 2/ = CFD photo-product from multiple-photon dissociation of dichlorotrifluoroethane, satisfying the high isotopic selectivity for economically viable photochemical deuterium separation. Its major drawback at present is the need to operate at low pressure. IR laser-induced bimolecular reactions may permit operation at higher pressure, and attractive processes include the methane + halogen and acetylene + hydrogen halide reaction systems. Single-photon induced ultraviolet dissociation using formaldehyde permits relatively high pressure operation, high single-step deuterium enrichment factors, and near-unity quantum yield. However, uv laser average power, efficiency, and lifetime, even based on the new XeCl or KrF excimer systems, still need substantial development to be used in an industrially viable process.

  5. Deuterium in New Zealand rivers and streams

    International Nuclear Information System (INIS)

    Over 750 deuterium measurements on rivers and streams in New Zealand are reported. Monthly samples were collected for periods of several years from a number of representative rivers. These show irregular storm-to-storm as well as seasonal deuterium variations. The seasonal variations range from as low as 1 per mille for lake-fed rivers to 8-10 per mille for rivers with large spring snow-melt contributions. Variations in mean annual ΔD values are believed to reflect changes in climatic variables; the present data will be used to compare with future changes. The bulk of the data are single samples; these show a geographic variation related to the altitude, latitude and climatic character of the catchments, with the highest deuterium contents (ΔD = -20 per mille) occurring in the far north, and lowest contents (-80 per mille) in the inland Otago region. Regression equations derived for the ΔD dependence on altitude (h) and latitude (l), are ΔD = -0.0169 h - 30.2 and westerly influence. Eastern climatic zones have lower deuterium contents because of rainout effects on the axial ranges. Contours of constant

  6. Emission of Secondary Electrons from Solid Deuterium

    DEFF Research Database (Denmark)

    Sørensen, H.

    An experimental facility was built where films of solid deuterium of known thickness could be made and where they could be irradiated with pulsed beams of electrons (up to 3 keV) and light ions (up to 10 keV). Studies of secondary electron emission were made and the secondary electron emission...

  7. The use of deuterium in medicine

    International Nuclear Information System (INIS)

    Whenever a corporal function experiences a disturbance reflected either by changes in metabolic activity or modifications of the importance of pools of certain molecules the possibility exists of making use of isotopes in diagnosis. This paper discusses the use of deuterium to measure total body water and extravascular water in the lungs, and gives examples of clinical applications

  8. Multifocal interferometric synthetic aperture microscopy

    OpenAIRE

    Xu, Yang; Chng, Xiong Kai Benjamin; Adie, Steven G.; Boppart, Stephen A.; Scott Carney, P.

    2014-01-01

    There is an inherent trade-off between transverse resolution and depth of field (DOF) in optical coherence tomography (OCT) which becomes a limiting factor for certain applications. Multifocal OCT and interferometric synthetic aperture microscopy (ISAM) each provide a distinct solution to the trade-off through modification to the experiment or via post-processing, respectively. In this paper, we have solved the inverse problem of multifocal OCT and present a general algorithm for combining mu...

  9. Short term dynamic aperture with AC dipoles

    CERN Document Server

    Mönig, Saskia; Persson, Tobias Hakan Bjorn; Coello De Portugal, Jaime; Langner, Andy; Tomas, Rogelio; CERN. Geneva. ATS Department

    2015-01-01

    The dynamic aperture of an accelerator is determined by its non-linear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and non-linear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the non-linear dynamics, the dynamic aperture with and without AC dipole are expected to differ. The effect of the AC dipole on the dynamic aperture is studied within this note.

  10. Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments

    International Nuclear Information System (INIS)

    Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13–17 MeV) and down-scattered (6–12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

  11. Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments.

    Science.gov (United States)

    Guler, N; Volegov, P; Danly, C R; Grim, G P; Merrill, F E; Wilde, C H

    2012-10-01

    Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms. PMID:23126842

  12. DEUTERIUM CHEMISTRY IN PROTOPLANETARY DISKS. II. THE INNER 30 AU

    International Nuclear Information System (INIS)

    We present the results of models of the chemistry, including deuterium, in the inner regions of protostellar disks. We find good agreement with recent gas-phase observations of several (non-deuterated) species. We also compare our results with observations of comets and find that in the absence of other processing, e.g., in the accretion shock at the surface of the disk, or by mixing in the disk, the calculated D/H ratios in ices are higher than measured and reflect the D/H ratio set in the molecular cloud phase. Our models give quite different abundances and molecular distributions to other inner disk models because of the differences in physical conditions in the model disk. This emphasizes how changes in the assumptions about the density and temperature distribution can radically affect the results of chemical models.

  13. Optimized baffle and aperture placement in neutral beamlines

    International Nuclear Information System (INIS)

    Most neutral beamlines contain an iron-core ion-bending magnet that requires shielding between the end of the neutralizer and this magnet. This shielding allows the gas pressure to drop prior to the beam entering the magnet and therefore reduces beam losses in this drift region. We have found that the beam losses can be reduced even further by eliminating the iron-core magnet and the magnetic shielding altogether. The required bending field can be supplied by current coils without the iron poles. In addition, placement of the baffles and apertures can affect the cold gas entering the plasma region and the losses in the neutral beam due to re-ionization. In our study we varied the placement of the baffles, which determine the amount of pumping in each chamber, and the apertures, which determine the beam loss. Our results indicate that a baffle/aperture configuration can be set for either minimum cold gas into the plasma region or minimum beam losses, but not both

  14. Hydrogen and deuterium in vanadium as lattice gases with repulsive short-range interactions. Wasserstoff und Deuterium in Vanadium als wechselwirkende Gittergase

    Energy Technology Data Exchange (ETDEWEB)

    Meuffels, P.

    1986-08-01

    Pressure-composition isotherms at temperatures between 150 and 550/sup 0/C for solutions of hydrogen and deuterium in vanadium and the temperature dependence of the heat capacity in a series of V-D alloys have been determined in the single phase regions (..cap alpha..-phase) of the V-H(D) phase diagrams. The concentration dependences of the partial molar enthalpies ..delta..anti H/sub H(D)/ and entropies ..delta..anti S/sub H(D)/ of hydrogen and deuterium have been derived from the solubility data. For both isotopes ..delta..anti H/sub H(D)/ decreases with increasing H or D concentration x = (H(D))/(V) at low x and increases a higher H or D content, having a minimum near xapprox. =0.4. The concentration dependence of ..delta..anti S/sub H(D)/ shows a large negative deviation from the ideal configurational entropy for random occupation of tetrahedral interstitial sites. The heat capacity of V-D/sub x/ contains a substantial excess contribution, which remains when estimated electronic and vibrational contribution are subtracted from the experimental data. The experimental results are analyzed by means of Monte Carlo simulations of a lattice gas with repulsive short range interactions between hydrogen (deuterium) atoms. The essential features of the experimental results are described by a lattice gas model which includes hard core interactions (blocking effect) and finite repulsive interactions outside the hard core.

  15. Cosmic Deuterium and Social Networking Software

    Science.gov (United States)

    Pasachoff, J. M.; Suer, T.-A.; Lubowich, D. A.; Glaisyer, T.

    2006-08-01

    For the education of newcomers to a scientific field and for the convenience of students and workers in the field, it is helpful to have all the basic scientific papers gathered. For the study of deuterium in the Universe, in 2004-5 we set up http://www.cosmicdeuterium.info with clickable links to all the historic and basic papers in the field and to many of the current papers. Cosmic deuterium is especially important because all deuterium in the Universe was formed in the epoch of nucleosynthesis in the first 1000 seconds after the Big Bang, so study of its relative abundance (D:H~1:100,000) gives us information about those first minutes of the Universe's life. Thus the understanding of cosmic deuterium is one of the pillars of modern cosmology, joining the cosmic expansion, the 3 degree cosmic background radiation, and the ripples in that background radiation. Studies of deuterium are also important for understanding Galactic chemical evolution, astrochemistry, interstellar processes, and planetary formation. Some papers had to be scanned while others are available at the Astrophysical Data System, adswww.harvard.edu, or to publishers' Websites. By 2006, social networking software (http:tinyurl.com/ zx5hk) had advanced with popular sites like facebook.com and MySpace.com; the Astrophysical Data System had even set up MyADS. Social tagging software sites like http://del.icio.us have made it easy to share sets of links to papers already available online. We have set up http://del.icio.us/deuterium to provide links to many of the papers on cosmicdeuterium.info, furthering previous del.icio.us work on /eclipses and /plutocharon. It is easy for the site owner to add links to a del.icio.us site; it takes merely clicking on a button on the browser screen once the site is opened and the desired link is viewed in a browser. Categorizing different topics by keywords allows subsets to be easily displayed. The opportunity to expose knowledge and build an ecosystem of web

  16. Directional synthetic aperture flow imaging

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Nikolov, Svetoslav

    2004-01-01

    A method for flow estimation using synthetic aperture imaging and focusing along the flow direction is presented. The method can find the correct velocity magnitude for any flow angle and full color flow images can be measured using only 32 to 128 pulse emissions. The approach uses spherical wave...... emissions using a number of defocused elements and a linear frequency modulated pulse (chirp) to improve the signal-to-noise ratio. The received signals are dynamically focused along the flow direction and these signals are used in a cross-correlation estimator for finding the velocity magnitude. The flow...

  17. The Large Aperture GRB Observatory

    CERN Document Server

    Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

    2009-01-01

    The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the high energy (around 100 GeV) component of Gamma Ray Bursts, using the single particle technique in arrays of Water Cherenkov Detectors (WCD) in high mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela, 4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range. The status of the Observatory and data collected from 2007 to date will be presented.

  18. Ultrasonic large aperture imaging system

    International Nuclear Information System (INIS)

    A new ultrasonic large aperture imaging technique is described. This device combines a focussed transducer as a transmitter, producing a small ultrasonic beam, with N transducers as receivers. We show that is possible to considerably reduce the number of receivers if, on the one hand, we limit the reconstitution process to the emitter beam area and, on the other hand, we ensure that the artefacts, caused by the spatial sampling of the reception, are outside this area. Under these conditions, the result is a high resolution image which does not require large reconstitution processing times. Theoretical and experimental results are given

  19. Preparations for deuterium tritium experiments on the Tokamak Fusion Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hawryluk, R.J.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J.W.; Arunasalam, V.; Ascione, G.; Ashcroft, D.; Barnes, G. [and others

    1994-04-01

    The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR). These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a Fluorinet{sup {trademark}} system, modification of the vacuum system to handle tritium, preparation and testing of the neutral beam system for tritium operation and a final deuterium-deuterium (D-D) run to simulate expected deuterium-tritium (D-T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D-T experiments using D-D have been performed. The physics objectives of D-T operation are production of {approximately} 10 megawatts (MW) of fusion power, evaluation of confinement and heating in deuterium-tritium plasmas, evaluation of {alpha}-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined {alpha}-particles. Experimental results and theoretical modeling in support of the D-T experiments are reviewed.

  20. Preparations for deuterium--tritium experiments on the Tokamak Fusion Test Reactor*

    Energy Technology Data Exchange (ETDEWEB)

    Hawryluk, R.J.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J.L.; Anderson, J.W.; Arunasalam, V.; Ascione, G.; Aschroft, D.; Barnes, C.W.; Barnes, G.; Batchelor, D.B.; Bateman, G.; Batha, S.; Baylor, L.A.; Beer, M.; Bell, M.G.; Biglow, T.S.; Bitter, M.; Blanchard, W.; Bonoli, P.; Bretz, N.L.; Brunkhorst, C.; Budny, R.; Burgess, T.; Bush, H.; Bush, C.E.; Camp, R.; Caorlin, M.; Carnevale, H.; Chang, Z.; Chen, L.; Cheng, C.Z.; Chrzanowski, J.; Collazo, I.; Collins, J.; Coward, G.; Cowley, S.; Cropper, M.; Darrow, D.S.; Daugert, R.; DeLooper, J.; Duong, H.; Dudek, L.; Durst, R.; Efthimion, P.C.; Ernst, D.; Faunce, J.; Fonck, R.J.; Fredd, E.; Fredrickson, E.; Fromm, N.; Fu, G.Y.; Furth, H.P.; Garzotto, V.; Gentile, C.; Gettelfinger, G.; Gilbert, J.; Gioia, J.; Goldfinger, R.C.; Golian, T.; Gorelenkov, N.; Gouge, M.J.; Grek, B.; Grisham, L.R.; Hammett, G.; Hanson, G.R.; Heidbrink, W.; Hermann, H.W.; Hill, K.W.; Hirshman, S.; Hoffman, D.J.; Hosea, J.; Hulse, R.A.; Hsuan, H.; Ja

    1994-05-01

    The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. [bold 21], 1324 (1992)]. These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a Fluorinert[sup TM] system, modification of the vacuum system to handle tritium, preparation, and testing of the neutral beam system for tritium operation and a final deuterium--deuterium (D--D) run to simulate expected deuterium--tritium (D--T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D--T experiments using D--D have been performed. The physics objectives of D--T operation are production of [approx]10 MW of fusion power, evaluation of confinement, and heating in deuterium--tritium plasmas, evaluation of [alpha]-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined [alpha] particles. Experimental results and theoretical modeling in support of the D--T experiments are reviewed.

  1. The Deuterium Fractionation Timescale in Dense Cloud Cores: A Parameter Space Exploration

    CERN Document Server

    Kong, Shuo; Tan, Jonathan C; Wakelam, Valentine

    2013-01-01

    The deuterium fraction of simple species such as N$_2$H$^+$ can be easily measured and can provide information about the age of dense and cold material, important to compare with dynamical models of cloud core formation and evolution. Here we perform a parameter space exploration using a gas-phase chemical model which includes deuterium chemistry and the spin states of H$_2$ and H$_3^+$ isotopologues. This allows us to study the effect of various poorly known parameters on the timescale to achieve the deuterium fractions observed in starless cores and clumps in various star-forming regions. We conclude that for a broad range of parameters, the relatively large deuterium fractions ($\\gtrsim$ 0.1) observed towards both low- and high-mass starless cores require core ages to be at least a few times longer than the free-fall timescale. This condition could be relaxed if cosmic ray ionization rates are very high $\\gtrsim 10^{-16}\\:{\\rm s}^{-1}$ or initial ortho-to-para ratios of $\\rm H_2$ are very low ($\\lesssim 10...

  2. Preparations for deuterium tritium experiments on the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR). These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a Fluorinettrademark system, modification of the vacuum system to handle tritium, preparation and testing of the neutral beam system for tritium operation and a final deuterium-deuterium (D-D) run to simulate expected deuterium-tritium (D-T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D-T experiments using D-D have been performed. The physics objectives of D-T operation are production of ∼ 10 megawatts (MW) of fusion power, evaluation of confinement and heating in deuterium-tritium plasmas, evaluation of α-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined α-particles. Experimental results and theoretical modeling in support of the D-T experiments are reviewed

  3. Deuterium chemistry in the Orion Bar PDR - "warm" chemistry starring CH2D+

    OpenAIRE

    Parise, B.; Leurini, S.; Schilke, P.; Roueff, E.; Thorwirth, S.; Lis, D.C.

    2009-01-01

    Context. High levels of deuterium fractionation in gas-phase molecules are usually associated with cold regions, such as prestellar cores. Significant fractionation ratios are also observed in hot environments such as hot cores or hot corinos, where they are believed to be produced by the evaporation of the icy mantles surrounding dust grains, and are thus remnants of a previous cold (either gasphase or grain surface) chemistry. The recent detection of DCN towards the Orion Bar, in a clump at...

  4. The Deuterium Fractionation Timescale in Dense Cloud Cores: A Parameter Space Exploration

    OpenAIRE

    Kong, Shuo; Caselli, Paola; Tan, Jonathan C.; Wakelam, Valentine; Sipilä, Olli

    2013-01-01

    The deuterium fraction [N$_2$D$^+$]/[N$_2$H$^+$], may provide information about the ages of dense, cold gas structures, important to compare with dynamical models of cloud core formation and evolution. Here we introduce a complete chemical network with species containing up to three atoms, with the exception of the Oxygen chemistry, where reactions involving H$_3$O$^+$ and its deuterated forms have been added, significantly improving the consistency with comprehensive chemical networks. Deute...

  5. The primordial deuterium abundance problems and prospects

    CERN Document Server

    Levshakov, S A; Kegel, W H; Levshakov, Sergei A.; Takahara, Fumio; Kegel, Wilhelm H.

    1997-01-01

    The current status of extragalactic deuterium abundance is discussed using two examples of `low' and `high' D/H measurements. We show that the discordance of these two types of D abundances may be a consequence of the spatial correlations in the stochastic velocity field. Within the framework of the generalized procedure (accounting for such effects) one finds good agreement between different observations and the theoretical predictions for standard big bang nucleosynthesis (SBBN). In particular, we show that the deuterium absorption seen at z = 2.504 toward Q1009+2956 and the H+D Ly-alpha profile observed at z = 0.701 toward Q1718+4807 are compatible with D/H $\\sim 4.1 - 4.6\\times10^{-5}$. This result supports SBBN and, thus, no inhomogeneity is needed. The problem of precise D/H measurements is discussed.

  6. Deuterium and tritium diffusion and permeation barriers

    International Nuclear Information System (INIS)

    Deuterium permeation barriers have been successfully formed on Ni. One approach using Al+ ion implantation followed by thermal oxidation reduced the permeability by a factor of ∼2. In another approach, permeability was reduced by a factor of ∼50 using pack-aluminized Ni. Al2O3 layers ∼1000 A thick have been formed on Ni by sputter deposition. These have been shown to act as permeation barriers but as yet no measurements of the permeability have been obtained. Thin film Ni samples have now been produced that have deuterium diffusion coefficients that are within a factor of 4 of bulk values. A preliminary measurement has been carried out that indicates a reduction in diffusion coefficient due to radiation damage

  7. Deuterium retention in Tore Supra long discharges

    International Nuclear Information System (INIS)

    Tritium retention is a crucial point to investigate for next step machines using carbon plasma facing components. In order to address this issue, particle balance has been performed on Tore Supra long discharges, allowing to estimate the wall deuterium inventory. In these conditions, large dynamic deuterium retention rates have been observed (up to 50% of the injected fuel). This paper presents a summary of the experimental results in terms of wall retention during the shot and particle recovery after the shot, as well as after glow discharges and disruptions. Particle balance integrated over a campaign is also estimated and compared with the D inventory deduced from sample analysis. Different mechanisms are then reviewed in order to explain this particle balance, from D particle implantation to carbon porosity filling and co-deposition. Rough estimates of each process contribution to the retention rates are given and compared with the experimental observations. (authors)

  8. Cosmological implications of two conflicting deuterium abundances

    International Nuclear Information System (INIS)

    Constraints on big bang nucleosynthesis (BBN) and on cosmological parameters from conflicting deuterium observations in different high redshift QSO systems are discussed. The high deuterium observations by Carswell et al., Songaila et al., and Rugers and Hogan are consistent with 4He and 7Li observations and standard BBN (Nν =3) and allows Nν≤3.6 at 95% C.L., but are inconsistent with local observations of D and 3He in the context of conventional theories of stellar and galactic evolution. In contrast, the low deuterium observations by Tytler, Fan, and Burles and Burles and Tytler are consistent with the constraints from local galactic observations, but require Nν=1.9±0.3 at 68% C.L., excluding standard BBN at 99.9% C.L., unless the systematic uncertainties in the 4He observations have been underestimated by a large amount. The high and low primordial deuterium abundances imply, respectively, ΩBh2=0.005 endash 0.01 and ΩBh2=0.02 endash 0.03 at 95% C.L. When combined with the high baryon fraction inferred from x-ray observations of rich clusters, the corresponding total mass densities (for 50≤H0≤90) are ΩM=0.05 endash 0.20 and ΩM=0.2 endash 0.7, respectively (95% C.L.). The range of ΩM corresponding to high D is in conflict with dynamical constraints (Ωm≥0.2 endash 0.3) and with the shape parameter constraint (Γ=ΩMh=0.25±0.05) from large scale structure formation in CDM and ΛCDM models. copyright 1997 The American Physical Society

  9. Temperature dependence of deuterium retention in tungsten deposits by deuterium ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, K., E-mail: kadzu@nucl.kyushu-u.ac.jp [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Uehara, K.; Date, H.; Fukada, S. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Watanabe, H. [Research Institute for Applied Mechanics, Kyushu University, 6-1, Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan)

    2015-08-15

    Tungsten (W) deposits were formed by hydrogen plasma sputtering and blisters were observed on the surface. The W deposits and W foils were exposed to deuterium ions with 2 keV-D{sup 2+} to doses of 1.0 × 10{sup 21} D{sup 2+}/m{sup 2} at 294 and 773 K in addition to 573 K in the present authors’ previous work. Hydrogen isotopes release behaviors from the W deposits and W foils were observed by the thermal desorption spectroscopy method. The amount of deuterium released from the W deposit was considerably larger than that from W foil. The obtained deuterium retention in D/m{sup 2} was in the range of deuterium retention in polycrystalline tungsten. Not only implanted deuterium but also hydrogen, which was incorporated during the sputtering-deposition process, were released from the W deposits. A hydrogen release peak at around 1100 K was observed for the W deposits. This is considered to be due to the rupture of the blisters.

  10. Is Deuterium Nuclear Fusion Catalyzed by Antineutrinos?

    Science.gov (United States)

    Shomer, Isaac

    2010-02-01

    The hypothesis of Fischbach and Jenkins that neutrinos emitted from the sun accelerate radioactive decay is noted. It is thought that neutrinos accelerate beta decay by reacting with neutron-rich nuclides to form a beta particle and a daughter product, with no antineutrino emitted. Conversely, it is proposed that antineutrinos can react with proton-rich nuclides to cause positron decay, with no neutrino emitted. It is also proposed that the nuclear fusion of the hydrogen bomb is triggered not only by the energy of the igniting fission bomb, but by the antineutrinos created by the rapid beta decay of the daughter products in the fission process. The contemplated mechanism for antineutrino initiated fusion is the following: 1. The antineutrinos from the fission daughter products cause positron decay of deuterium by the process outlined above. 2. In a later fusion step, these positrons subsequently react with neutrons in deuterium to create antineutrinos. Electrons are unavailable to annihilate positrons in the plasma of the hydrogen bomb. 3. These antineutrinos thereafter react with more deuterium to form positrons, thereby propagating a chain reaction. )

  11. Muon transfer from deuterium to helium

    CERN Document Server

    Augsburger, M A; Breunlich, W H; Cargnelli, M; Chatellard, D; Egger, J P; Gartner, B; Hartmann, F J; Huot, O; Jacot-Guillarmod, R; Kammel, P; King, R; Knowles, P; Kosak, A; Lauss, B; Marton, J; Mühlbauer, M; Mulhauser, F; Petitjean, C; Prymas, W; Schaller, L A; Schellenberg, L; Schneuwly, H; Tresch, S; Von Egidy, T; Zmeskal, J

    2003-01-01

    We report on an experiment at the Paul Scherrer Institute, Villigen, Switzerland measuring x rays from muon transfer from deuterium to helium. Both the ground state transfer via the exotic dmu3,4He* molecules and the excited state transfer from mud* were measured. The use of CCD detectors allowed x rays from 1.5 keV to 11 keV to be detected with sufficient energy resolution to separate the transitions to different final states in both deuterium and helium. The x-ray peaks of the dmu3He* and dmu4He* molecules were measured with good statistics. For the D2+3He mixture, the peak has its maximum at E_dmu3He = 6768 +- 12 eV with FWHM Gamma_dmu3He = 863 +- 10 eV. Furthermore the radiative branching ratio was found to be kappa_dmu3He = 0.301 +- 0.061. For the D_2+4He mixture, the maximum of the peak lies at E_dmu4He = 6831 +- 8 eV and the FWHM is Gamma_dmu4He = 856 +- 10 eV. The radiative branching ratio is kappa_dmu4He = 0.636 +- 0.097. The excited state transfer is limited by the probability to reach the deuterium...

  12. Resonant Effects in Nanoscale Bowtie Apertures

    Science.gov (United States)

    Ding, Li; Qin, Jin; Guo, Songpo; Liu, Tao; Kinzel, Edward; Wang, Liang

    2016-06-01

    Nanoscale bowtie aperture antennas can be used to focus light well below the diffraction limit with extremely high transmission efficiencies. This paper studies the spectral dependence of the transmission through nanoscale bowtie apertures defined in a silver film. A realistic bowtie aperture is numerically modeled using the Finite Difference Time Domain (FDTD) method. Results show that the transmission spectrum is dominated by Fabry-Pérot (F-P) waveguide modes and plasmonic modes. The F-P resonance is sensitive to the thickness of the film and the plasmonic resonant mode is closely related to the gap distance of the bowtie aperture. Both characteristics significantly affect the transmission spectrum. To verify these numerical results, bowtie apertures are FIB milled in a silver film. Experimental transmission measurements agree with simulation data. Based on this result, nanoscale bowtie apertures can be optimized to realize deep sub-wavelength confinement with high transmission efficiency with applications to nanolithography, data storage, and bio-chemical sensing.

  13. Practical Applications of Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav Ivanov; Kortbek, Jacob; Jensen, Jørgen Arendt

    2010-01-01

    Synthetic aperture imaging has been a focus of research for almost 3 decades. The research carried out at the Center for Fast Ultrasound Imaging has demonstrated that synthetic aperture focusing not only can be used in-vivo, but that it also yields superior B-mode and blood flow images. In the last...... years synthetic aperture focusing has moved from the lab to commercial products. The implementations vary in their scope and purpose. Some scanners use synthetic aperture imaging to improve the detail and contrast resolution of the system. Others to increase the image uniformity. Yet others use...... synthetic aperture acquisition to achieve high frame rates and superior flow estimations. On the other end of the scale are the systems that utilize synthetic aperture techniques to reduce the data rate and take advantage of modern computer hardware. Retrospecitve transmit beamformation, zone sonography...

  14. Doppler synthetic aperture hitchhiker imaging

    International Nuclear Information System (INIS)

    In this paper we consider passive airborne receivers that use backscattered signals from sources of opportunity transmitting single-frequency or ultra-narrowband waveforms. Because of its combined passive synthetic aperture and the single-frequency nature of the transmitted waveforms, we refer to the system under consideration as Doppler synthetic aperture hitchhiker (DSAH). We present a novel image formation method for DSAH. Our method first correlates the windowed signal obtained from one receiver with the windowed, filtered, scaled and translated version of the received signal from another receiver. This processing removes the transmitter-related variables from the phase of the Fourier integral operator that maps the radiance of the scene to the correlated signal. Next, we use microlocal analysis to reconstruct the scene radiance by the weighted backprojection of the correlated signal. The image reconstruction method is applicable to both cooperative and non-cooperative sources of opportunity using one or more airborne receivers. It has the desirable property of preserving the visible edges of the scene radiance. Additionally, it is an analytic reconstruction technique that can be made computationally efficient. We present numerical simulations to demonstrate the performance of the image reconstruction method and to verify the theoretical results

  15. Advanced Optics Experiments Using Nonuniform Aperture Functions

    CERN Document Server

    Wood, Lowell T

    2012-01-01

    A method to create instructive, nonuniform aperture functions using spatial frequency filtering is described. The diffraction from a single slit in the Fresnel limit and the interference from a double slit in the Fraunhofer limit are spatially filtered to create electric field distributions across an aperture to produce apodization, inverse apodization or super-resolution, and apertures with phase shifts across their widths. The diffraction effects from these aperture functions are measured and calculated. The excellent agreement between the experimental results and the calculated results makes the experiment ideal for use in an advanced undergraduate or graduate optics laboratory to illustrate experimentally several effects in Fourier optics.

  16. Ion mobility spectrometer with virtual aperture grid

    Science.gov (United States)

    Pfeifer, Kent B.; Rumpf, Arthur N.

    2010-11-23

    An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

  17. Practical Applications of Synthetic Aperture Imaging

    OpenAIRE

    Nikolov, Svetoslav Ivanov; Kortbek, Jacob; Jensen, Jørgen Arendt

    2010-01-01

    Synthetic aperture imaging has been a focus of research for almost 3 decades. The research carried out at the Center for Fast Ultrasound Imaging has demonstrated that synthetic aperture focusing not only can be used in-vivo, but that it also yields superior B-mode and blood flow images. In the last years synthetic aperture focusing has moved from the lab to commercial products. The implementations vary in their scope and purpose. Some scanners use synthetic aperture imaging to improve the det...

  18. Deuterium-tritium experiments on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Bretz, N.L.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J.W.; Arunasalam, V.; Ascione, G.; Barnes, C.W.; Barnes, G.; Batha, S.; Bateman, G.; Beer, M.; Bell, M.G.; Bell, R.; Bitter, M.; Blanchard, W.; Brunkhorst, C.; Budny, R.; Bush, C.E.; Camp, R.; Caorlin, M.; Carnevale, H.; Cauffman, S.; Chang, Z.; Cheng, C.; Chrzanowski, J.; Collins, J.; Coward, G.; Cropper, M.; Darrow, D.S.; Daugert, R.; DeLooper, J.; Dorland, W.; Dudek, L.; Duong, H.; Durst, R.; Efthimion, P.C.; Ernst, D.; Evensen, H.; Fisch, N.; Fisher, R.; Fonck, R.J.; Fredd, E.; Fredrickson, E.; Fromm, R.; Fu, G.; Fujita, T.; Furth, H.P.; Garzotto, V.; Gentile, C.; Gilbert, J.; Giola, J.; Gorelenkov, N.; Grek, B.; Grisham, L.R.; Hammett, G.; Hanson, G.R.; Hawryluk, R.J.; Heidbrink, W.; Herrmann, H.W.; Hill, K.W.; Hosea, J.; Hsuan, H.; Hughes, M.; Hulse, R.; Janos, A.; Jassby, D.L.; Jobes, F.C.; Johnson, D.W.; Johnson, L.C.; Kalish, M.; Kamperschroer, J.; Kesner, J.; Kugel, H.; Labik, G.; Lam, N.T.; LaMarche, P.H.; Lawson, E.; LeBlanc, B.; Levine, J.; Levinton, F.M.; Loesser, D.; Long, D.; Loughlin, M.J.; Machuzak, J.; Majeski, R.; Mansfield, D.K.; Marmar, E.; Marsala, R.; Martin, A.; Martin, G.; Mauel, M.; Mazzucato, E.; McCarthy, M.P.; McChesney, J.; McCormack, B.; McCune, D.C.; McGuire, K.M.; McKee, G.; Meade, D.M.; Medley, S.S.; Mikkelsen, D.R.; Mirnov, S.V.; Mueller, D.; Murakami, M.; Murphy, J.A.; Nagy, A.; Navratil, G.A.; Nazikian, R.; Newman, R.; Norris, M.; OConnor, T.; Oldaker, M.; Ongena, J.; Osakabe, M.; Owens, D.K.; Park, H.; Park, W.; Parks, P.; Paul, S.F.; Pearson, G.; Perry, E.; Persing, R.; Petrov, M.; Phillips, C.K.; Phillips, M.; Pitcher, S.; Pysher, R.; Qualls, A.L.; Raftapoulos, S.; Ramakrishnan, S.; Ramsey, A.; Rasmunsen, D.A.; Redi, M.H.; Renda, G.; Rewoldt, G.; Roberts, D.; Rogers, J.; Rossmassler, R.; Roquemore, A.L.; Ruskov, E.; Sabbaugh, S.A.; Sasao, M.; Schilling, G.; Schivell, J.; Schmidt, G.L.; Scillia, R.; Scott, S.D.; Semenov, I.; Senko, T.

    1995-09-01

    A peak fusion power production of 9.3{plus_minus}0.7 MW has been achieved on the Tokamak Fusion Test Reactor (TFTR) in deuterium plasmas heated by co and counter injected deuterium and tritium neutral beams with a total power of 33.7 MW. The ratio of fusion power output to heating power input is 0.27. At the time of the highest neutron flux the plasma conditions are: {ital T}{sub {ital e}}(0)=11.5 keV, {ital T}{sub {ital i}}(0)=44 keV, {ital n}{sub {ital e}}(0)=8.5{times}10{sup 19} m{sup {minus}3}, and {l_angle}{ital Z}{sub eff}{r_angle}=2.2 giving {tau}{sub {ital E}}=0.24 s. These conditions are similar to those found in the highest confinement deuterium plasmas. The measured D-T neutron yield is within 7% of computer code estimates based on profile measurements and within experimental uncertainties. These plasmas have an inferred central fusion alpha fraction of 0.2% and central fusion power density of 2 MW/m{sup 3} similar to that expected in a fusion reactor. Even though the alpha velocity exceeds the Alfven velocity throughout the time of high neutron output in most high power plasmas, MHD activity is similar to that in comparable deuterium plasmas and Alfven wave activity is low. The measured loss rate of energetic alpha particles is about 3% of the total as expected from alphas which are born on unconfined orbits. Compared to pure deuterium plasmas with similar externally applied conditions, the stored energy in electrons and ions is about 25% higher indicating improvements in confinement associated with D-T plasmas and consistent with modest electron heating expected from alpha particles. ICRF heating of D-T plasmas using up to 5.5 MW has resulted in 10 keV increases in central ion and 2.5 keV increases in central electron temperatures in relatively good agreement with code predictions. In these cases heating on the magnetic axis at 2{Omega}{sub {ital T}} gave up to 80% of the ICRF energy to ions. {copyright} {ital 1995 American Institute of Physics.}

  19. Deuterium-tritium experiments on TFTR

    International Nuclear Information System (INIS)

    A peak fusion power production of 9.3±0.7 MW has been achieved on the Tokamak Fusion Test Reactor (TFTR) in deuterium plasmas heated by co and counter injected deuterium and tritium neutral beams with a total power of 33.7 MW. The ratio of fusion power output to heating power input is 0.27. At the time of the highest neutron flux the plasma conditions are: Te(0)=11.5 keV, Ti(0)=44 keV, ne(0)=8.5x1019 m-3, and left-angle Zeff right-angle=2.2 giving τE=0.24 s. These conditions are similar to those found in the highest confinement deuterium plasmas. The measured D-T neutron yield is within 7% of computer code estimates based on profile measurements and within experimental uncertainties. These plasmas have an inferred central fusion alpha fraction of 0.2% and central fusion power density of 2 MW/m3 similar to that expected in a fusion reactor. Even though the alpha velocity exceeds the Alfven velocity throughout the time of high neutron output in most high power plasmas, MHD activity is similar to that in comparable deuterium plasmas and Alfven wave activity is low. The measured loss rate of energetic alpha particles is about 3% of the total as expected from alphas which are born on unconfined orbits. Compared to pure deuterium plasmas with similar externally applied conditions, the stored energy in electrons and ions is about 25% higher indicating improvements in confinement associated with D-T plasmas and consistent with modest electron heating expected from alpha particles. ICRF heating of D-T plasmas using up to 5.5 MW has resulted in 10 keV increases in central ion and 2.5 keV increases in central electron temperatures in relatively good agreement with code predictions. In these cases heating on the magnetic axis at 2ΩT gave up to 80% of the ICRF energy to ions. copyright 1995 American Institute of Physics

  20. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core.

    Science.gov (United States)

    Ötvös, Sándor B; Hsieh, Chi-Ting; Wu, Yang-Chang; Li, Jih-Heng; Chang, Fang-Rong; Fülöp, Ferenc

    2016-01-01

    Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological effects and improved metabolic properties as compared with the parent compounds. PMID:26959006

  1. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core

    Directory of Open Access Journals (Sweden)

    Sándor B. Ötvös

    2016-03-01

    Full Text Available Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological effects and improved metabolic properties as compared with the parent compounds.

  2. Mineralized water depleted in deuterium and production technique

    International Nuclear Information System (INIS)

    Mineralized water depleted in deuterium is similar to natural water but has an isotopic content of 30-120 ppm D/(D+H). One can obtain mineralized water depleted in deuterium both in continuous and in discontinuous way by mixing deuterium depleted water with strong mineralized water obtained by vacuum distillation at atmospheric pressure of natural water. The mixture is saturated with oxygen by bubbling dry air into it at ambient temperature. This invention allows obtaining a product depleted in deuterium similar to natural water with biostimulating properties that can be used as developing medium for living organisms or for human use. The invention has the following qualities: allows the production of deuterium depleted water with chemical composition similar to natural water; allows the precise control of deuterium content in the product. (authors)

  3. Deuterium excess in precipitation and its climatological significance

    International Nuclear Information System (INIS)

    The climatological significance of the deuterium excess parameter for tracing precipitation processes is discussed with reference to data collected within the IAEA/WMO Global Network for Isotopes in Precipitation (GNIP) programme. Annual and monthly variations in deuterium excess, and their primary relationships with δ18O, temperature, vapour pressure and relative humidity are used to demonstrate fundamental controls on deuterium excess for selected climate stations and transects. The importance of deuterium excess signals arising from ocean sources versus signals arising from air mass modification during transport over the continents is reviewed and relevant theoretical development is presented. While deuterium excess shows considerable promise as a quantitative index of precipitation processes, the effectiveness of current applications using GNIP is largely dependent on analytical uncertainty (∼2.1 per mille), which could be improved to better than 1 per mille through basic upgrades in routine measurement procedures for deuterium analysis. (author)

  4. Direct in vivo characterization of delta 5 desaturase activity in humans by deuterium labeling: Effect of insulin

    International Nuclear Information System (INIS)

    The conversion of dihomogamma linolenic acid (DHLA) into arachidonic acid (AA) was compared in normal subjects and diabetic patients before and after treatment with insulin. The kinetics of the incorporation of deuterium-labeled DHLA and its conversion product, deuterium-labeled AA, was determined in plasma triglycerides, plasma phospholipids, and platelet lipids of subjects after ingestion of 2 g of the labeled precursor. Analysis was performed by gas liquid chromatography-mass spectrometry using multiple ion detection. In normal subjects, the deuterium-labeled DHLA concentration rose to 24 to 69 mg/L in plasma triglycerides four to nine hours after ingestion and to 20 to 34 mg/L in plasma phospholipids about four hours later. Deuterium-labeled AA appeared at 12 hours, rose to 2.4 to 3.8 mg/L between 48 and 72 hours in plasma phospholipids, but remained at the limit of detection in plasma triglycerides and was undetectable in platelet lipids. In diabetic patients both before and after insulin treatment, the deuterium-labeled DHLA concentration in plasma triglycerides and in plasma phospholipids followed the same pattern as in normal subjects. However, the deuterium-labeled arachidonic acid concentration was below 1 mg/L in plasma phospholipids before insulin. After insulin treatment the patients recovered normal DHLA metabolism because deuterium-labeled AA rose in phospholipids to a mean value of 3.5 mg/L, which is in the same range as that observed in normal subjects (3.2 mg/L). The present data provide direct evidence for the conversion of DHLA into AA in humans. The effect of insulin and the data from the literature of animal studies suggest insulin dependence of delta 5 desaturase in humans

  5. Multifocal interferometric synthetic aperture microscopy.

    Science.gov (United States)

    Xu, Yang; Chng, Xiong Kai Benjamin; Adie, Steven G; Boppart, Stephen A; Carney, P Scott

    2014-06-30

    There is an inherent trade-off between transverse resolution and depth of field (DOF) in optical coherence tomography (OCT) which becomes a limiting factor for certain applications. Multifocal OCT and interferometric synthetic aperture microscopy (ISAM) each provide a distinct solution to the trade-off through modification to the experiment or via post-processing, respectively. In this paper, we have solved the inverse problem of multifocal OCT and present a general algorithm for combining multiple ISAM datasets. Multifocal ISAM (MISAM) uses a regularized combination of the resampled datasets to bring advantages of both multifocal OCT and ISAM to achieve optimal transverse resolution, extended effective DOF and improved signal-to-noise ratio. We present theory, simulation and experimental results. PMID:24977909

  6. Synthetic aperture interferometry: error analysis

    International Nuclear Information System (INIS)

    Synthetic aperture interferometry (SAI) is a novel way of testing aspherics and has a potential for in-process measurement of aspherics [Appl. Opt.42, 701 (2003)].APOPAI0003-693510.1364/AO.42.000701 A method to measure steep aspherics using the SAI technique has been previously reported [Appl. Opt.47, 1705 (2008)].APOPAI0003-693510.1364/AO.47.001705 Here we investigate the computation of surface form using the SAI technique in different configurations and discuss the computational errors. A two-pass measurement strategy is proposed to reduce the computational errors, and a detailed investigation is carried out to determine the effect of alignment errors on the measurement process.

  7. Performance of multi-aperture grid extraction systems for an ITER-relevant RF-driven negative hydrogen ion source

    Science.gov (United States)

    Franzen, P.; Gutser, R.; Fantz, U.; Kraus, W.; Falter, H.; Fröschle, M.; Heinemann, B.; McNeely, P.; Nocentini, R.; Riedl, R.; Stäbler, A.; Wünderlich, D.

    2011-07-01

    The ITER neutral beam system requires a negative hydrogen ion beam of 48 A with an energy of 0.87 MeV, and a negative deuterium beam of 40 A with an energy of 1 MeV. The beam is extracted from a large ion source of dimension 1.9 × 0.9 m2 by an acceleration system consisting of seven grids with 1280 apertures each. Currently, apertures with a diameter of 14 mm in the first grid are foreseen. In 2007, the IPP RF source was chosen as the ITER reference source due to its reduced maintenance compared with arc-driven sources and the successful development at the BATMAN test facility of being equipped with the small IPP prototype RF source ( {\\sim}\\frac{1}{8} of the area of the ITER NBI source). These results, however, were obtained with an extraction system with 8 mm diameter apertures. This paper reports on the comparison of the source performance at BATMAN of an ITER-relevant extraction system equipped with chamfered apertures with a 14 mm diameter and 8 mm diameter aperture extraction system. The most important result is that there is almost no difference in the achieved current density—being consistent with ion trajectory calculations—and the amount of co-extracted electrons. Furthermore, some aspects of the beam optics of both extraction systems are discussed.

  8. Deuterium trapping in carbon fiber composites exposed to D plasma

    Energy Technology Data Exchange (ETDEWEB)

    Airapetov, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Begrambekov, L., E-mail: lbb@plasma.mephi.r [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Brosset, C.; Gunn, J.P.; Grisolia, C. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Kuzmin, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Loarer, T.; Lipa, M.; Monier-Garbet, P. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Shigin, P. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Tsitrone, E. [Association EURATOM-CEA, CEA/DSM/DRFC Cadarache, 13108 St. Paul lez Durance (France); Zakharov, A. [Plasma Physics Department, Moscow Engineering and Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation)

    2009-06-15

    Deuterium trapping in carbon fiber composite N11 and pyrolitic graphite PG99 irradiated with plasma ions and electrons was examined with thermal desorption spectrometry. It has been found that the deuterium trapping takes place even at ion and electron energies of about 10 eV. For equal ion fluences, the deuterium retention and probability of CD{sub 4} formation are higher for ion irradiation at lower ion flux. Peculiarities of the deuterium retention and CD{sub 4} formation are explained; driving forces and mechanisms of the D trapping are discussed.

  9. Synthesis of pteroylglutamic acid-3',5'-2H2 by trifluoroacetic acid catalyzed exchange with deuterium oxide

    International Nuclear Information System (INIS)

    Pteroylglutamic acid (PGA) was deuterated by trifluoroacetic acid catalyzed exchange with deuterium oxide. The product, pteroylglutamic acid-3',5'-2H2, was specifically deuterated in the aromatic protons of the p-aminobenzoyl (PABA) moiety; the protons on C7 and C9 and in the glutamic acid residue were not exchanged. Deuterium incorporation was measured by chemical ionization mass spectrometry (CI-MS). Pteroylglutamates were cleaved by a base-catalyzed, oxidative hydrolysis to PABA, which was converted to the methyl ester, N-trifluoroacetate for analysis by gas chromatography-chemical ionization-mass spectrometry. Products from the exchange typically contained 1 percent 2H1 and 90 percent 2H2 species. The procedure may be used to label specifically various analogs of PGA with deuterium in the PABA portion of the molecule

  10. Basic study of cold fusion. 2. Development of the measurement system of deuterium loading ratio in palladium cathode

    International Nuclear Information System (INIS)

    A measurement system of deuterium loading ratio in the palladium cathode, which is one of the most important factors for cold fusion phenomena, especially excess heat generation, has been introduced to the simultaneous measurement device of heat, neutron and gamma-ray of heavy water electrolysis that had been developed. Pressure of the gas phase in the closed electrolysis cell and electro-conductivity of the palladium cathode were measured to calculate the deuterium loading ratio. The measured ratio by means of each method is adequate compared with the reported results, and turned out to reach approximately 0.87. Simultaneous and continuous measurement of deuterium loading ratio with heat and neutron made reproduction of the situation of cold fusion phenomena and precision measurement of the heat generation possible. (author)

  11. Synthetic aperture radar: principles and applications

    International Nuclear Information System (INIS)

    In this paper an introduction to synthetic aperture radar is presented. Synthetic aperture radar is a relatively new remote sensing platform and the technology has matured a lot in the last two decades. This paper introduces the concepts behind SAR principles as well as the major areas where this new technology has shown additional information. (author)

  12. Experimental and numerical analyses of a hydrogen and deuterium storage system

    International Nuclear Information System (INIS)

    Highlights: • Experimental data to develop a real-time tritium storage control system. • Simulation (3D modeling) of real working conditions for long term tritium storage on titanium. • No major differences between the reaction of hydrogen and deuterium on titanium sponge were revealed. -- Abstract: This paper conducts an experiment and a three-dimensional (3D) modeling study for the absorption of hydrogen and deuterium on a storage tank with titanium sponge bed in order to simulate the real working conditions of a tritium storage system prior to tritium service. The 3D model is further numerically implemented and experimentally validated. The model is composed of an energy balance, mass balance and momentum balance and hydriding reaction kinetics. These differential equations are solved using finite element method. The experimental consisting in absorption of hydrogen and deuterium gas was made in batch made, under vacuum condition. Before absorption, an activation of the titanium bed was performed. A number of loading and releasing operations typically required in tritium handling loops were conducted using one bed containing a well determined quantity of titanium sponge. A comparison between theoretical results and experimental data has found that the gas was not uniformly absorbed on the metal bed volume. This work provides an important platform to understand the phenomena during tritium absorption on a titanium storage bed and the development of a real-time tritium storage control system

  13. Thermal emission by a subwavelength aperture

    Science.gov (United States)

    Joulain, Karl; Ezzahri, Younès; Carminati, Rémi

    2016-04-01

    We calculate, by means of fluctuational electrodynamics, the thermal emission of an aperture separating from the outside, vacuum or a material at temperature T. We show that thermal emission is very different whether the aperture size is large or small compared to the thermal wavelength. Subwavelength apertures separating vacuum from the outside have their thermal emission strongly decreased compared to classical blackbodies which have an aperture much larger than the wavelength. A simple expression of their emissivity can be calculated and their total emissive power scales as T8 instead of T4 for large apertures. Thermal emission of disk of materials with a size comparable to the wavelength is also discussed. It is shown in particular that emissivity of such a disk is increased when the material can support surface waves such as phonon polaritons.

  14. Biological effects of deuterium - depleted water

    International Nuclear Information System (INIS)

    Deuterium-depleted water (DDW) is represented by water that has an isotopic content smaller than 145 ppm D/(D + H). DDW production technique consists in the separation of deuterium from water by a continuous distillation process under pressure of about 133.3 mbar. The water used as raw material has a isotopic content of 145 ppm D/(D + H) and can be demineralized water, distillated water or condensed-steam. DDW results as a distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 the Institute of Cryogenics and Isotopic Technologies, DDW producer, co-operated with Romanian specialized institutes for studying the biological effects of DDW. The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. These investigations led to the following conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the DDW persists after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defense mechanisms; - DDW stimulates immuno-defense reactions represented by the opsonic, bactericidal and phagocyte capacity of the immune system together with an increase in the number of poly-morphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance and following growth stages; - It was studied germination, growth and quantitative character variability in plants; one can remark the favorable influence of DDW on biological processes in plants in various ontogenetic stages. (authors)

  15. Synthesis of deuterium labelled cocaine and pseudococaine

    International Nuclear Information System (INIS)

    Cocaine and pseudococaine were mass-labelled with deuterium at various positions on the tropane ring. The synthetic procedures followed were adaptations of those previously published for the unlabelled compounds. The isotopic purity was greater than 95% for 2-[2H]-, 4,4-[2H2]-, and 1,5,6,6,7,7-[2H6]-cocaine and 3-[2H]-, 4,4-[2H2]-, and 1,5,6,6,7,7-[2H6]-pseudococaine, while that of 3-[2H]-cocaine exceeded 90%. (author)

  16. Recent findings on blistering and deuterium retention in tungsten exposed to high-fluence deuterium plasma

    International Nuclear Information System (INIS)

    Full text of publication follows: Blistering occurs at tungsten exposed to high-fluence deuterium plasma, even if the ion energy is too low to create displacement damage [1, 2]. In this study, blistering and deuterium retention in various tungsten exposed to high-fluence (up to 1027 D/m2 ) of high flux (1022 D+/m2/s) and low-energy (38 eV) deuterium plasma were examined in the temperature range of 315 K to 1000 K with scanning electron microscopy (SEM), focused ion beam (FIB), thermal desorption spectroscopy (TDS) and positron annihilation (PA). At the exposure temperature of 315 K, only low-dome blisters with sizes of less than a few microns appeared even if the fluence reached 1027 D/m2. At around 400 K, the blisters became much denser and the dome of blisters became a little higher. Peculiar change occurred around 500 K, where two kinds of blisters appeared. One is the large blisters with sizes of a few tens of microns and varying ratios of height against chord (up to 0.6), and the other is the high-dome small blisters with chords of less than a few microns and large ratio of height against chord (about 0.7). Blisters became much sparser as the temperature increased to above 600 K and disappeared at 1000 K. In addition, the phenomenon of blister bursting with a tail, or partially-opened or fully-opened lid was found after plasma exposure or TDS experiments . During TDS experiments, bursting release with numerous sadden peaks was newly observed by setting the time resolution of quadrupole mass spectrometer to about 0.3 s. Deuterium retention showed the maximum around 500 K, corresponding to the appearance of two kinds of high-dome blisters. furthermore, the amount of deuterium retained in tungsten increased with the increasing fluence, roughly following the proportional relationship with the root of the exposure time. Besides the strong dependence upon the exposure temperature, blistering and deuterium retention also showed significant dependence upon the

  17. Experiments on palladium- and titanium-deuterium systems with reference to studies on ''cold fusion''

    International Nuclear Information System (INIS)

    The work performed at Risoe in connection with the claims of ''cold fusion'' is summarised in this report. The main purpose of the whole experiment was to analyse if structural anomalies of deuterated metals could support the occurrence of fusion processes in such systems by x-ray and neutron powder diffraction methods. Two types of systems were investigated. The first one was an electrolytic cell with palladium as electrode. No anomalous properties in the composition and positions of deuterium were found in this case. The other one was a titanium-deuterium-gas system which was studied in order to reproduce the ''Frascati experiment''. However, no neutrons above the background level were observed in spite of the very sensitive detector system. By neutron diffraction of this system a 70% titanium-dideuterium phase was found. (author)

  18. Liquid deuterium neutron attenuator for broad-band photon beam facility

    International Nuclear Information System (INIS)

    The photo-production facility at Fermilab uses a two section liquid deuterium attenuator, 103 feet in length, to reduce the neutron flux and produce a pure high energy photon beam. The facility is located in the Proton East experimental hall, and includes nine 10 foot long sweeping magnets. A unique refrigeration system supplies mechanically refrigerated helium gas trace cooling to condense deuterium directly in a flask. The control system permits remote operation of the cryogenic system and also acts as an interface to the Proton Area operations computer. The computer can be used to monitor the operating parameters and for partial control of the system. The facility is presently in use as part of the Proton Area experimental program. (auth)

  19. Tritium and deuterium labelling studies of alkali metal borohydrides and their application to simple reductions

    International Nuclear Information System (INIS)

    Simple and facile syntheses of highly deuterated and tritiated LiBH4, NaBH4 and KBH4 were achieved by hydrogen isotope exchange with deuterium or tritium gas at elevated temperatures. The exchange products were characterized by boron, proton and deuterium or tritium NMR spectroscopy. The extent of isotope (2H or 3H) incorporation was calculated from the patterns of 11B NMR spectra. Several samples of tritiated NaBH4 were treated with BF3-Et2O to produce tritiated borane-THF complex, which is an electrophilic reducing agent. The utility of both the borohydride reagents and borane-THF complex in labelling reactions was confirmed by exemplary reductions leading to specifically labelled products. The extent and orientation of labelling in the reduction products was assessed by a combination of radio-HPLC analysis, 1H, 2H or 3H NMR and mass spectrometry. (author)

  20. Metal liner-driven cylindrically convergent isentropic compression of cryogenic deuterium

    Science.gov (United States)

    Weinwurm, Marcus; Bland, Simon N.; Chittenden, Jeremy P.

    2014-05-01

    In order to take advantage of geometrical convergence, we investigated a method, where a beryllium liner drives a cylindrical shockless compression in a cryogenic deuterium fill. The metal liner acts as a current carrier as well as a pressure boundary to the fill. The required driving pressure was obtained through a fictitious flow (FF) simulation [D S Clark and M Tabak 2007 Nucl. Fusion 47 1147]. A current model that can recreate the FF compression inside the liner by shaping the current pulse, is then introduced. This method also allows efficient compression of hydrogen at low entropy, enabling the recreation of conditions present in the interior of gas giants and potentially the observation of a transition into a metallic state. Our two-dimensional simulations show that thick liners remain robust to magneto-Rayleigh-Taylor instability growth, suggesting that cylindrical isentropic ramp compression is a promising scheme for extending deuterium's experimentally measured equation of state.

  1. Analysis of deuterium in V-Fe5at.% film by atom probe tomography (APT)

    KAUST Repository

    Gemma, Ryota

    2011-09-01

    V-Fe5at.% 2 and 10-nm thick single layered films were prepared by ion beam sputtering on W substrate. They were loaded with D from gas phase at 0.2 Pa and at 1 Pa, respectively. Both lateral and depth D distribution of these films was investigated in detail by atom probe tomography. The results of analysis are in good agreement between the average deuterium concentration and the value, expected from electromotive force measurement on a similar flat film. An enrichment of deuterium at the V/W interface was observed for both films. The origin of this D-accumulation was discussed in respect to electron transfer, mechanical stress and misfit dislocations. © 2010 Elsevier B.V. All rights reserved.

  2. Deuterium retention and release from tungsten

    International Nuclear Information System (INIS)

    The design of a future fusion reactor requires an understanding of the hydrogen isotope (protium, deuterium, and tritium) retention and recycling that will occur during operation. Retention of the hydrogen isotopes is particularly important if the isotope is tritium. Retention of large quantities of tritium in the reactor plasma-facing components increases the fuel costs of the reactor and presents a safety concern. Tungsten is still one of the most promising materials in magnetic fusion energy as a plasma facing material. In the past, it has been used only sparingly due to the problem of excessive radiation losses in the plasma when tungsten is present in the plasma. Tungsten's use in fusion devices will increase in the future. Unfortunately, a prediction of tritium retention during realistic plasma conditions is difficult since there are a few reliable reports about interaction for the simplest interaction of gaseous hydrogen isotopes with tungsten at elevated temperatures. The discrepancy between data is large even for the most important material properties, such as the diffusion constant and solubility. We report the results of long term and precise measurements of hydrogen evolution kinetics at 1000 0C followed by low pressure exposures to deuterium at 500 0C and 1000 0C. (author)

  3. Permeation behavior of deuterium implanted into beryllium

    International Nuclear Information System (INIS)

    Study on Implantation Driven Permeation (IDP) behavior of deuterium through pure beryllium was investigated as a part of the research to predict the tritium permeation through the first wall components ITER (International Thermonuclear Experimental Reactor). The permeation experiments were carried out with two beryllium specimens, one was an unannealed specimen and the other was that annealed at 1173 K. The permeation flux was measured as a function of specimen temperature and incident ion flux. Surface analysis of specimen was also carried out after the permeation experiment. Permeation was observed only with the annealed specimen and no significant permeation was observed with unannealed specimen under the present experimental condition (maximum temperature: 685 K, detection limit: 1x1013 D atoms/m2s). It could be attributed that the intrinsic lattice defects, which act as diffusion preventing site, decreased with the specimen annealing. Based on the result of steady and transient permeation behavior and surface analysis, it was estimated that the deuterium permeation implanted into annealed beryllium was controlled by surface recombination due to the oxide layer on the surface of the permeated side. (author)

  4. Correlation of Tritium and Deuterium Isotope Effects

    International Nuclear Information System (INIS)

    The theory,of relative tritium-protium and deuterium-protium isotope effects is developed for both rate and equilibrium processes. It is shown that the relative effects in equilibrium processes vary with the strength of the chemical bonding and the temperature. A lower limit of 1.33 and an upper limit of 1.55 is established for ln αT-H/ln αD-H. Detailed calculations are given for a number of simple molecules. It is shown that the temperature independent frequency factor in rate processes increases the ratio ln (kH/kT)/ln (kH/kD) above the values found in equilibrium processes. Equations are given from which the increment can be calculated. It is shown that relative tritium-protium versus deuterium-protium isotope effects may be of diagnostic use in characterizing secondary isotope effects and tunnelling in chemical reactions. Detailed calculations are given for three types of processes involving water : (1) equilibration with hydrogen, (2) distillation, and (3) electrolysis. In these three different processes αD-H varies from 5 x 10-2 to 10, yet in (αT-H)/ln (αD-H) is calculated to be in the range 1.33 - 1.40 for all three processes, in excellent agreement with experiment. (author)

  5. Cryotarget Control Software for Liquid Deuterium

    Science.gov (United States)

    Brakman, David; Gilfoyle, Gerard; Cuevas, Chris; Christo, Steve; CLAS Collaboration

    2015-10-01

    One of the experiments in Hall B at Jefferson Lab will measure the neutron elastic magnetic form factor with a 12 GeV electron beam striking a liquid deuterium target (LD2) and measuring the resulting debris in the CEBAF Large Acceptance Spectrometer (CLAS12). A program was created that acts as a control system for the LD2 target. It will monitor the deuterium target and send data to the main control system and the shift workers monitoring the experiment in real time. The data include measurements of pressure, temperature, and liquid level. The system will also control setpoints for temperature, heater power, and other parameters as well as download calibration curves. The program was written in LabVIEW, a graphical programming language noted for readily interfacing with lab equipment. This project has completed two stages so far. Simulated data were generated within LabVIEW and passed to subroutines that send, log, and display data on a PC. In the second stage, the PC was connected to a data acquisition board, and test signals were read and analyzed to simulate the target sensors. Work supported by the University of Richmond and the US Department of Energy.

  6. Interferometric Synthetic Aperture Microscopy (ISAM)

    Science.gov (United States)

    Adie, Steven G.; Shemonski, Nathan D.; Ralston, Tyler S.; Carney, P. Scott; Boppart, Stephen A.

    The trade-off between transverse resolution and depth-of-field, and the mitigation of optical aberrations, are long-standing problems in optical imaging. The deleterious impact of these problems on three-dimensional tomography increases with numerical aperture (NA), and so they represent a significant impediment for real-time cellular resolution tomography over the typical imaging depths achieved with OCT. With optical coherence microscopy (OCM), which utilizes higher-NA optics than OCT, the depth-of-field is severely reduced, and it has been postulated that aberrations play a major role in reducing the useful imaging depth in OCM. Even at lower transverse resolution, both these phenomena produce artifacts that degrade the imaging of fine tissue structures. Early approaches to the limited depth-of-field problem in time-domain OCT utilized dynamic focusing. In spectral-domain OCT, this focus-shifting approach to data acquisition leads to long acquisition times and large datasets. Adaptive optics (AO) has been utilized to correct optical aberrations, in particular for retinal OCT, but in addition to requiring elaborate and expensive setups, the real-time optimization requirements at the time of imaging, and the correction of spatially varying effects of aberrations throughout an imaged volume, remain as significant challenges. This chapter presents computed imaging solutions for the reconstruction of sample structure when imaging with ideal and aberrated Gaussian beams.

  7. Confinement and heating of a deuterium-tritium plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hawryluk, R. J. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Adler, H. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Alling, P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Synakowski, E. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States). et al.

    1994-03-01

    The Tokamak Fusion Test Reactor (TFTR) has performed initial high-power experiments with the plasma fueled by deuterium and tritium to nominally equal densities. Compared to pure deuterium plasmas, the energy stored in the electron and ions increased by ~20%. These increases indicate improvements in confinement associated with the use of tritium and possibly heating of electrons by α-particles.

  8. Deuterium exchange between liquid water and gaseous hydrogen

    International Nuclear Information System (INIS)

    The overall separation factors for the deuterium exchange between liquid water and gaseous hydrogen have been calculated over a wide range of temperature, pressure and deuterium concentrations. These data would be useful in the design and other considerations for heavy water production, based on hydrogen-water exchange. (author)

  9. On the preparation of polymeric deuterium containing compounds

    International Nuclear Information System (INIS)

    Methods for preparing deuterium containing polymers are discussed. Relative merits of each method are brought forth. Experimental conditions for its preparation from deuterodiazomethane are described. Also, the syntheses of various deutero intermediates like perdeuteroacetyl methyl urea and perdeuteronitrosomethyl urea are incorporated. The methods used for estimating the deuterium content in the various deutero compounds are described. (author)

  10. Electromigration of hydrogen and deuterium in vanadium, niobium and tantalum

    International Nuclear Information System (INIS)

    The electric mobility and effective valence of hydrogen and deuterium in vanadium, niobium, tantalum and three niobium--tantalum alloys were measured. A resistance technique was used to directly determine the electric mobility of hydrogen and deuterium at 300C while a steady-state method was used to measure the effective valence

  11. Confinement and heating of a deuterium-tritium plasma

    International Nuclear Information System (INIS)

    The Tokamak Fusion Test Reactor (TFTR) has performed initial high-power experiments with the plasma fueled by deuterium and tritium to nominally equal densities. Compared to pure deuterium plasmas, the energy stored in the electron and ions increased by ∼20%. These increases indicate improvements in confinement associated with the use of tritium and possibly heating of electrons by α-particles

  12. Nuclear processes in deuterium/natural hydrogen-metal systems

    International Nuclear Information System (INIS)

    The survey presents the analysis of the phenomena taking place in deuterium - metal and natural hydrogen - metal systems under cold fusion experimental conditions. The cold fusion experiments have shown that the generation of heat and helium in the deuterium-metal system without emission of energetic gamma-quanta is the result of occurrence of a chain of chemical, physical and nuclear processes observed in the system, culminating in both the fusion of deuterium nuclei and the formation of a virtual, electron-modified excited 4He nucleus. The excitation energy of the helium nucleus is transferred to the matrix through emission of conversion electrons, and that, under appropriate conditions, provides a persistent synthesis of deuterium. The processes occurring in the deuterium/natural hydrogen - metal systems have come to be known as chemonuclear DD- and HD-fusion. The mechanism of stimulation of weak interaction reactions under chemonuclear deuterium fusion conditions by means of strong interaction reactions has been proposed. The results of numerous experiments discussed in the survey bear witness to the validity of chemonuclear fusion. From the facts discussed it is concluded that the chemonuclear deuterium fusion scenario as presented in this paper may serve as a basis for expansion of deeper research and development of this ecologically clean energy source. It is shown that the natural hydrogen-based system, containing 0.015% of deuterium, also has good prospects as an energy source. The chemonuclear fusion processes do not require going beyond the scope of traditional physics for their explanation

  13. Sputtering of solid deuterium by He-ions

    DEFF Research Database (Denmark)

    Schou, Jørgen; Stenum, B.; Pedrys, R.

    2001-01-01

    Sputtering of solid deuterium by bombardment of 3He+ and 4He+ ions was studied. Some features are similar to hydrogen ion bombardment of solid deuterium, but for the He-ions a significant contribution of elastic processes to the total yield can be identified. The thin-film enhancement is more...

  14. Deuterium behavior in first-wall materials for nuclear fusion

    International Nuclear Information System (INIS)

    Plasma-wall interactions play an important part while choosing materials for the first wall in future fusion reactors. Moreover, the use of tritium as a fuel will impose safety limits regarding the total amount present in the tokamak. Previous analyses of first-wall samples exposed to fusion plasma highlighted an in-bulk migration of deuterium (as an analog to tritium) in carbon materials. Despite its limited value, this retention is problematic: contrary to co-deposited layers, it seems very unlikely to recover easily the deuterium retained in such a way. Because of the difficult access to in situ samples, most published studies on the subject were carried out using post-mortem sample analysis. In order to access to the dynamic of the phenomenon and come apart potential element redistribution during storage, we set up a bench intended for simultaneous low-energy ion implantation, reproducing the deuterium interaction with first-wall materials, and high-energy micro beam analysis. Nuclear reaction analysis performed at the micrometric scale (μNRA) allows to characterize deuterium repartition profiles in situ. This analysis technique was confirmed to be non-perturbative of the mechanisms studied. We observed on the experimental data set that the material surface (0-1 μm) display a high and nearly constant deuterium content, with a uniform distribution. On the contrary, in-bulk deuterium (1-11 μm) localizes in preferential trapping sites related to the material microstructure. In-bulk deuterium inventory seems to increase with the incident fluence, in spite of the wide data scattering attributed to the structure variation of studied areas. Deuterium saturation at the surface as well as in-depth migration are instantaneous; in-vacuum storage leads to a small deuterium global desorption. Observations made via μNRA were coupled with results from other characterization techniques. X-ray μtomography allowed to identify porosities as the preferential trapping sites

  15. Fast Parametric Beamformer for Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Jensen, Jørgen Arendt; Tomov, Borislav Gueorguiev

    2008-01-01

    This paper describes the design and implementation of a real-time delay-and-sum synthetic aperture beamformer. The beamforming delays and apodization coefficients are described parametrically. The image is viewed as a set of independent lines that are defined in 3-D by their origin, direction, and...... implementation of the beamformer is optimized with respect to the architecture of a novel synthetic aperture real-time ultrasound scanner (SARUS), in which 4 channels are processed by the same set of field-programmable gate arrays (FPGA). In synthetic transmit aperture imaging, low-resolution images are formed...

  16. New directions in the theory of spin-polarized atomic hydrogen and deuterium

    International Nuclear Information System (INIS)

    The three chapters of this thesis dealing with collisions between hydrogen (or deuterium) atoms in their ground state, each treat a different development in the theory of atomic hydrogen or deuterium gas. The decay due to interatomic collisions hindered till now all attempts to reach the low temperature, high-density regime where effects due to degeneracy are expected to show up. In ch. 2 a simple way out is presented for the case of Fermi gases: In spin-polarized Fermi systems at very low temperatures collisions are much effective than in Bose systems. For the Fermi gas, consisting of magnetically confined deuterium atoms, it appears that fast spin-exchange collisions automatically lead to a completely spin-polarized gas for which the spin-relaxation limited lifetime increases dramatically with decreasing temperature. As also the ratio of internal thermalization rate over decay rate increases with decreasing temperature, this gas can be cooled by forced evaporation down to very low temperatures. In ch. 3 it iis shown that the nuclear spin dynamics due to the hyperfine interaction during collisions, strongly limits the improvement in frequency stability attainable by H masers operating at low temperatures. In ch. 4 the phenomenon of spin waves is studied. It is shown that, despite the fact that interactions between two atoms are nuclear-spin independent, the outcome of a scattering event does not depend on the nuclear spins involved due to the particle indistinguishability effects at low collision energies. This effect gives rise to quantum phenomena on a macroscopic scale via the occurrence of spin waves. (author). 185 refs.; 34 figs

  17. Deuterium Abundance in Consciousness and Current Cosmology

    Science.gov (United States)

    Rauscher, Elizabeth A.

    We utilize the deuterium-hydrogen abundances and their role in setting limits on the mass and other conditions of cosmogenesis and cosmological evolution. We calculate the dependence of a set of physical variables such as density, temperature, energy mass, entropy and other physical variable parameters through the evolution of the universe under the Schwarzschild conditions as a function from early to present time. Reconciliation with the 3°K and missing mass is made. We first examine the Schwarzschild condition; second, the geometrical constraints of a multidimensional Cartesian space on closed cosmologies, and third we will consider the cosmogenesis and evolution of the universe in a multidimensional Cartesian space, obeying the Schwarzschild condition. Implications of this model for matter creation are made. We also examine experimental evidence for closed versus open cosmologies; x-ray detection of the "missing mass" density. Also the interstellar deuterium abundance, along with the value of the Hubble constant set a general criterion on the value of the curvature constant, k. Once the value of the Hubble constant, H is determined, the deuterium abundance sets stringent restrictions on the value of the curvature constant k by an detailed discussion is presented. The experimental evidences for the determination of H and the primary set of coupled equations to determine D abundance is given. 'The value of k for an open, closed, or flat universe will be discussed in terms of the D abundance which will affect the interpretation of the Schwarzschild, black hole universe. We determine cosmology solutions to Einstein's field obeying the Schwarzschild solutions condition. With this model, we can form a reconciliation of the black hole, from galactic to cosmological scale. Continuous creation occurs at the dynamic blackhole plasma field. We term this new model the multiple big bang or "little whimper model". We utilize the deuteriumhydrogen abundances and their role in

  18. Thermal Emission by a Subwavelength Aperture

    CERN Document Server

    Joulain, Karl; Carminati, Rémi

    2015-01-01

    We calculate, by means of fluctuational electrodynamics, the thermal emission of an aperture filled by vacuum or a material at temperature T. We show that thermal emission is very different whether the aperture size is large or small compared to the thermal wavelength. Subwavelength apertures filled with vacuum (subwavelength blackbody) have their thermal emission strongly decreased compared to classical blackbodies. A simple expression of their emissivity can be calculated and their total emittance scales as T 8 instead of T 4 for large apertures. Thermal emission of disk of materials with a size comparable to the wavelength is also discussed. It is shown in particular that emissivity of such a disk is increased when the material can support surface waves such as phonon polaritons.

  19. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for funding to continue development of an alternative beam combiner for Stellar Imager (SI), a 30-aperture, interferometric telescope chosen as one...

  20. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Stellar Imager, an ultraviolet, sparse-aperture telescope, was one of the fifteen Vision Missions chosen for a study completed last year. Stellar Imager will...

  1. Synthetic Aperture Radar Missions Study Report

    Science.gov (United States)

    Bard, S.

    2000-01-01

    This report reviews the history of the LightSAR project and summarizes actions the agency can undertake to support industry-led efforts to develop an operational synthetic aperture radar (SAR) capability in the United States.

  2. Channeling effect in polycrystalline deuterium-saturated CVD diamond target bombarded by deuterium ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Bagulya, A.V.; Dalkarov, O.D. [Lebedev Physical Institute RAS, Moscow (Russian Federation); Negodaev, M.A., E-mail: negodaev@sci.lebedev.ru [Lebedev Physical Institute RAS, Moscow (Russian Federation); Rusetskii, A.S., E-mail: rusets@lebedev.ru [Lebedev Physical Institute RAS, Moscow (Russian Federation); Chubenko, A.P. [Lebedev Physical Institute RAS, Moscow (Russian Federation); Ralchenko, V.G.; Bolshakov, A.P. [Prokhorov General Physics Institute RAS, Moscow (Russian Federation); National Research Nuclear University MEPhI, Moscow (Russian Federation)

    2015-07-15

    At the ion accelerator HELIS at LPI, the neutron yield is investigated in DD reactions within a strongly textured polycrystalline deuterium-saturated CVD diamond under irradiation by a deuterium ion beam with the energy of less than 30 keV. The measurements of the neutron flux in the beam direction are performed using a multichannel detector based on {sup 3}He counters, in dependence on the target angle, β, with respect to the beam axis. A significant anisotropy in the neutron yield is observed. At β = 0° the yield is higher by a factor of 3 as compared to that at β = ±45°. The possible reasons for the anisotropy, including ion channeling, are discussed.

  3. Channeling Effect in Polycrystalline Deuterium-Saturated CVD Diamond Target Bombarded by Deuterium Ion Beam

    CERN Document Server

    Bagulya, A V; Negodaev, M A; Rusetskii, A S; Chubenko, A P; Ralchenko, V G; Bolshakov, A P

    2014-01-01

    At the ion accelerator HELIS at the LPI, the neutron yield is investigated in DD reactions within a polycrystalline deuterium-saturated CVD diamond, during an irradiation of its surface by a deuterium ion beam with the energy less than 30 keV. The measurements of the neutron flux in the beam direction are performed in dependence on the target angle, \\b{eta}, with respect to the beam axis. These measurements are performed using a multichannel detector based on He3 counters. A significant anisotropy in neutron yield is observed, it was higher by a factor of 3 at \\b{eta}=0 compared to that at \\b{eta} = +-45{\\deg}. The possible reasons for the anisotropy, including ion channeling, are discussed.

  4. Oxidation and deuterium uptake of Zr-2.5Nb pressure tubes in CANDU-PHW reactors

    International Nuclear Information System (INIS)

    Oxidation and deuterium uptake in Zr-2.5Nb pressure tubes are being monitored by destructive examination of tubes removed from commercial Canadian deuterium uranium pressurized heavy-water (CANDU-PHW) stations and by analyses of microsamples, obtained in-situ, from the inside surface of tubes in the reactor. Unlike Zircaloy-2, there is no evidence for any acceleration in the oxidation rate for exposures up to about 4500 effective full power days. Changes towards a more equilibrium microstructure during irradiation may be partly responsible for maintaining the low oxidation rate, since thermal aging treatments, producing similar microstructural changes in initially cold worked tubes, were found to improve out-reactor corrosion resistance in 589 K water. With one exception, the deuterium uptake in Zr-2.5Nb tubes has been remarkably low and no greater than 3-mg/kg deuterium per year (0.39 mg/dm2 hydrogen per year) . The exception is the most recent surveillance tube removed from Pickering (NGS) Unit 3, which had a deuterium content near the outlet end about five times higher than that seen in the previous tube examined. Current investigations suggest that most of the uptake in that tube may have come from the gas annulus surrounding the tube where deuterium exists as an impurity, and oxidation has been insufficient to maintain a protective oxide film. Results from weight gain measurements, chemical analyses, metallography, scanning electron microscopy, and transmission electron microscopy of irradiated pressure tubes and of small coupons exposed out reactor are presented and discussed with respect to the observed corrosion and hydriding behavior of CANDU-PHW pressure tubes. (author)

  5. Isotopic effect in the radiolytic deuterium production in PHWR (pressurized heavy water reactors)

    International Nuclear Information System (INIS)

    The isotopic concentration factor α = (H atoms/D atoms)gas/(H atoms/D atoms)liquid was determined in the deuterium gas dissolved in the primary system of Atucha I Nuclear Station (CNA I) and in the cover gas of the moderator and feed water tank of the primary system in Embalse Nuclear Station (CNE). The applied gas chromatographic method allowed the determination of D2, HD and H2 in the samples. The following α values were found: 3.5 ± 1.3 for the D2 dissolved in the primary system of CNA I, and 15 ≤ 2 and 88 ± 58 for the cover gases of the feed water tank and the moderator of CNE respectively. A number of possible factors causing the changes in α were analyzed. (Author)

  6. Fresnel aperture pre-stack depth migration

    OpenAIRE

    2005-01-01

    In this thesis, I present the results of a new approach to pre-stack Kirchoff depth migration using the Kirchoff algorithm and the Fresnel aperture features in order to improve the signal-to-noise ratio of the seismic data in depth imaging. Another advantage of this method is that it requires no additionnal measurments compared to the traditionnal PSDM. Indeed, the Fresnel apertures are picked interactively, in a way that is similar to velocity picking, and thereafter used during the migratio...

  7. New multiple aperture arrangements for speckle photography

    OpenAIRE

    Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, Néstor

    2000-01-01

    Abstract. We propose a multiple exposure specklegram by using an optical system whose multiple aperture pupil changes between exposures. In particular, we analyze experimentally two arrangements and we show that it is possible to store the required information by employing a minimum number of registers if an adequate selection of the pupil is done. We study the effect of the decorrelation (among the stored speckle pattern) introduced by changing the multiple aperture pupil arrangements betwee...

  8. Synthetic Aperture Techniques for Sonar Systems

    OpenAIRE

    Silva, S&#;rgio Rui; Cunha, S&#;rgio; Matos, An&#;bal; Cruz, Nuno

    2009-01-01

    As demonstrated, synthetic aperture sonar is a technique that enables attainment of high quality, high resolution underwater images. Autonomous surface vehicles provides several advantages for synthetic aperture imagery. Not only it is possible to control the boat motion in this way, it is also possible to obtain navigation measurements with precisions in the order of the wavelength used in high resolution sonar systems. Furthermore unsupervised surveillance applications that combine the high...

  9. An autonomous boat based Synthetic Aperture Sonar

    OpenAIRE

    Sergio Rui Silva; Sergio Cunha; Anibal Matos; Nuno Cruz

    2007-01-01

    This paper describes a Synthetic Aperture Sonar (SAS) system being developed at the University of Porto to be used in a small autonomous boat for the survey of shallow water environments, such as rivers, deltas, estuaries and dams. Its purpose is to obtain high resolution echo reflectivity maps through synthetic aperture techniques, taking advantage of the high precision navigation system of the boat. In the future the production of bottom tomography maps is also considered through the use of...

  10. Catalyzed deuterium fueled tandem mirror reactor assessment

    International Nuclear Information System (INIS)

    This study was part of a Department of Energy supported alternate fusion fuels program at Science Applications International Corp. The purpose of this portion of the study is to perform an assessment of a conceptual tandem mirror reactor (TMR) that is fueled by the catalyzed-deuterium (Cat-d) fuel cycle with respect to the physics, technology, safety, and cost. Achievable stable betas and magnet configurations are found to be comparable for the Cat-d and d-t fueled TMR. A comparison with respect to cost, reactor performance, and technology requirements for a Cat-d fueled reactor and a comparable d-t fueled reactor such as MARS is also made

  11. Multiphoton dissociative ionization of molecular deuterium

    International Nuclear Information System (INIS)

    The kinetic energy spectra of deuterium ions produced from D2 arising from collision-free subpicosecond irradiation at 248 nm with intensities spanning the 10/sup 13/--10/sup 16/-W/cm2 range have been measured by time-of-flight analysis. The behaviors of the kinetic energy distributions of the fragments and the relative abundances of atomic (D+) and molecular (D2+) ions reveal the presence of two mechanisms of multiphoton dissociative ionization. Calibration of the energy scale for D+ is facilitated by comparison with He/sup 2+/. For intensities in the 10/sup 13/--10/sup 15/-W/cm2 region, intermediate three-photon resonances and the optical Stark shift play important roles. At an intensity /similar to/0/sup 16/ W/cm2, a direct transition from the molecular ground state to the dissociative ionic level appears as a significant channel. No evidence of direct double ionization was observed

  12. Deuterium pellet injection in the TFR Tokamak

    International Nuclear Information System (INIS)

    Injecting fresh fuel deep inside the plasma of a thermonuclear reactor appears to be necessary; the only way to do that is to inject fast solid deuterium pellets. The existing theoretical, technical and experimental aspects of this method are presented. The experiments on TFR have confirmed that injecting pellets is technically feasible; a new kind of injector is presented. The injection does not degrade stability nor confinement of the plasma. The study of the transient phenomena occuring during the injection has proved to be an efficient way to investigate particles and energy transport in the discharge; in particular, a fast transport phenomenon, similar to those occuring during disruptions, has been studied in details. Conclusions about disruptions are drawn. (Ref 101)

  13. Deuterium treatment of low water peak fiber

    Institute of Scientific and Technical Information of China (English)

    Xinwei QIAN; Deming LIU; Feng TU

    2009-01-01

    The deuterium (D2) treatment of low water peak single-mode fiber (LWP-SMF) after drawing has been investigated. The D2 treatment time and concentra-tion have important effect on fiber's properties after D2 treatment. The insufficient treatment of D2 cannot ensure fiber resistant to hydrogen aging, whereas excessive treatment of D2 will result in excess loss on fiber at 13 83 nm. The optimization on viscosity match between the core and the cladding is helpful on problem solving of excess loss after the D2 treatment. However, by designing proper time and D2 concentration in the D2 treatment process, it can produce fiber with good hydrogen aging resistance and low excess loss and lower the cost of the D2 treatment process.

  14. The Evaluation and Quantitation of Dihydrogen Metabolism Using Deuterium Isotope in Rats.

    Directory of Open Access Journals (Sweden)

    Radomir Hyspler

    Full Text Available Despite the significant interest in molecular hydrogen as an antioxidant in the last eight years, its quantitative metabolic parameters in vivo are still lacking, as is an appropriate method for determination of hydrogen effectivity in the mammalian organism under various conditions.Intraperitoneally-applied deuterium gas was used as a metabolic tracer and deuterium enrichment was determined in the body water pool. Also, in vitro experiments were performed using bovine heart submitochondrial particles to evaluate superoxide formation in Complex I of the respiratory chain.A significant oxidation of about 10% of the applied dose was found under physiological conditions in rats, proving its antioxidant properties. Hypoxia or endotoxin application did not exert any effect, whilst pure oxygen inhalation reduced deuterium oxidation. During in vitro experiments, a significant reduction of superoxide formation by Complex I of the respiratory chain was found under the influence of hydrogen. The possible molecular mechanisms of the beneficial effects of hydrogen are discussed, with an emphasis on the role of iron sulphur clusters in reactive oxygen species generation and on iron species-dihydrogen interaction.According to our findings, hydrogen may be an efficient, non-toxic, highly bioavailable and low-cost antioxidant supplement for patients with pathological conditions involving ROS-induced oxidative stress.

  15. On the Deuterium-to-Hydrogen Ratio of the Interstellar Medium

    CERN Document Server

    Weinberg, David H

    2016-01-01

    Observations show that the global deuterium-to-hydrogen ratio (D/H) in the local interstellar medium (ISM) is about 90% of the primordial ratio predicted by big bang nucleosynthesis. The high (D/H)$_{ISM}$ implies that only a small fraction of interstellar gas has been processed through stars, which destroy any deuterium they are born with. Using analytic arguments for one-zone chemical evolution models that include accretion and outflow, I show that the deuterium abundance is tightly coupled to the abundance of core collapse supernova (CCSN) elements such as oxygen. These models predict that the ratio of (D/H)$_{ISM}$ to the primordial abundance is $\\approx 1/(1+r Z_O/m_O)$, where r is the recycling fraction, $Z_O$ is the ISM oxygen mass fraction, and $m_O$ is the population averaged CCSN yield of oxygen. Using values $r=0.4$ and $m_O=0.015$ appropriate to a Kroupa (2001) initial mass function and recent CCSN yield calculations, solar oxygen abundance corresponds to an ISM (D/H) that is 87\\% of the primordia...

  16. Investigation of compression of puffing neon by deuterium current and plasma sheath in plasma focus discharge

    Energy Technology Data Exchange (ETDEWEB)

    Kubes, P.; Cikhardt, J.; Cikhardtova, B.; Rezac, K.; Klir, D.; Kravarik, J.; Kortanek, J. [Czech Technical University Prague, Prague (Czech Republic); Paduch, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland)

    2015-06-15

    This paper presents the results of the research of the influence of compressed neon, injected by the gas-puff nozzle in front of the anode axis by the deuterium current and plasma sheath on the evolution of the pinch, and neutron production at the current of 2 MA. The intense soft X-ray emission shows the presence of neon in the central region of the pinch. During the implosion and stopping of the plasma sheath, the deuterium plasma penetrates into the internal neon layer. The total neutron yield of 10{sup 10}–10{sup 11} has a similar level as in the pure deuterium shots. The neutron and hard X-ray pulses from fusion D-D reaction are as well emitted both in the phase of the stopping implosion and during the evolution of instabilities at the transformation of plasmoidal structures and constrictions composed in this configuration from both gases. The fast deuterons can be accelerated at the decay of magnetic field of the current filaments in these structures.

  17. Deuterium depleted water. Present applications and prospects

    International Nuclear Information System (INIS)

    The deuterium depleted water, DDW, is distilled, microbiologically pure water with an isotopic concentration D/(D+H) under 145 ppm, the natural water value. At ICSI Rm Valcea a procedure was developed and a patent was recorded for the method and installation for obtaining DDW. The procedure consists in vacuum distillation of natural water on columns equipped with highly performing ordered packing. The system allows obtaining DDW at isotopic concentration within the range 20-120 ppm. Biological studies showed that treatment with this DDW reduced significantly the high rate in L929 linear fibroblast cells and annihilated the tumoral growth in xenotransplant. It was suggested that the deuterium occurring naturally has an essential in converting the signals regulating the cellular cycling. A vast program based on collaborations of ICSI with different specialized research institutes in Romania was initiated and important results already obtained among which one can mention: - DDW determines an increase of vascular reactivity seemingly endotelio-dependent and implying radical species (superoxides, nitric oxides); - immunity defense reaction represented by the opsonic, bactericide and phagocytic capacity are stimulated; - animals pre-treated with DDW present an increased resistance to both sub-lethal and lethal doses of gamma radiations, suggesting a radioprotective property; - study of artificial fecundation in fishes with fecundating solution containing an 1:1 mixture of DDW and distilled water showed the beneficent effects both in embryonal development and growth in alevins; - an increase of metabolism rate in aquatic macrophytes following the dilution of spectral energy of sea water mixed with DDW was observed; - studies on three genotypes of Zea mays showed significant effects on coleoptile growth. At present programs for studying prevention and treatment of tumors and various cancer forms are underway

  18. Deuterium depleted water. Romanian achievements and prospects

    International Nuclear Information System (INIS)

    The deuterium depleted water (DDW) is microbiologically pure distilled water with a deuterium content lower than that of natural waters which amounts to 140 - 150 ppm D/(D+H); variations depend on geographical zone and altitude. The procedure of obtaining DDW is based on isotopic separation of natural water by vacuum distillation. Isotope concentration can be chosen within 20 to 120 ppm D/(D+H). The ICSI at Rm. Valcea has patented the procedure and equipment for the production of DDW. According to the document SF-01-2002/INC-DTCI - ICSI Rm. Valcea, the product has a D/(D+H) isotope concentration of 25 ± 5. Studies and research for finding the effects and methods of application in different fields were initiated and developed in collaboration with different institutes in Romania. The following important results obtained so far could be mentioned: - absence of toxicity upon organisms; - activation of vascular reactivity; - enhancement of defence capacity of the organism through non-specific immunity activation; - increase of salmonid reproduction capacity and enhancement of the adaptability of alevins to the environmental conditions; - radioprotective effect to ionizing radiation; - maintaining meat freshness through osmotic shock; - stimulation of growth of aquatic macrophytes; - enhancement of culture plant development in certain ontogenetic stages. Mostly, the results and practical applications of the research were patented and awarded with gold medals at international invention fairs. At present, research-development programmes are undergoing to find active biological features of DDW in fighting cancer, on one hand, and its applicability as food additive of pets or performing animals, on the other hand

  19. Deuterium Measurements on Snow Samples from the Alps

    International Nuclear Information System (INIS)

    Measurements of the deuterium content of snow samples from different regions of the western and eastern Alps revealed a general difference between samples of fresh snow and pack snow. The deuterium content of fresh snow was found to decrease approximately linearly with increase in elevation. When ΔδD = -4%0 ± 2%o per 100 m rise in elevation, the deuterium content corresponded to the altitude effect measured so far for rain in Central Europe. Pack snow, on the other hand, showed an increase in deuterium content with rise in elevation which, for the samples examined, fell within the range of ΔδD = 5% ±3% per 100 m rise in elevation. Natural snow samples were used to follow and interpret the variation with time of the deuterium content caused by the ageing of the snow. In addition to the dependence of the deuterium content on elevation, there is also an annual pattern for the deterium content of snow samples which corresponds to the known curve for deuterium in precipitations. (author)

  20. Measurement of the ratio of hydrogen to deuterium at the KSTAR 2009 experimental campaign

    International Nuclear Information System (INIS)

    The control of the ratio of hydrogen to the deuterium is one of the very important issues for ion cyclotron range of frequency (ICRF) minority heating as well as the plasma wall interaction in the tokamak. The ratio of hydrogen to deuterium during the tokamak shot was deduced from the emission spectroscopy measurements during the KSTAR 2009 experimental campaign. Graphite tiles were used for the plasma facing components (PFCs) at KSTAR and its surface area exposed to the plasma was about 11 m2. The data showed that it remained as high as around 50% during the campaign period because graphite tiles were exposed to the air for about two months and the hydrogen contents at the tiles are not fully pumped out due to the lack of baking on the PFC in the 2009 campaign. The validation of the spectroscopy method was checked by using the Zeeman effects and the ratio of hydrogen to the deuterium is compared with results from the residual gas analysis. During the tokamak shot, the ratio is low below 10% initially and saturated after around 1 s. When there is a hydrogen injection to the vessel via ion cyclotron wall conditioning and the boronization process where the carbone is used, the ratio of the hydrogen to the deuterium is increased by up to 100% and it recovers to around 50% after one day of operation. However it does not decrease below 50% at the end of the experimental campaign. It was found that the full baking on the PFC (with a high temperature and sufficient vacuum pumping) is required for the ratio control which guarantees the efficient ICRF heating at the KSTAR 2010 experimental campaign.

  1. Electromigration of hydrogen and deuterium in vanadium, niobium, and tantalum

    International Nuclear Information System (INIS)

    The electric mobility and effective valence of hydrogen and deuterium in vanadium, niobium, tantalum and three niobium-tantalum alloys were measured. A resistance technique was used to directly determine the electric mobility of hydrogen and deuterium at 300C while a steady-state method was used to measure the effective valence. The use of mass spectrographic techniques on a single specimen which contained both hydrogen and deuterium greatly increased the precision with which the isotope effect in the effective valence could be measured

  2. UV luminescence of NeD in solid neon-deuterium mixtures

    DEFF Research Database (Denmark)

    Stenum, B.; Schou, Jørgen; Gürtler, P.

    1994-01-01

    Solid samples of neon-deuterium mixtures were irradiated by keV electrons, and the luminescence was measured between 100 and 300 nm. For concentrations between 0.1% D-2 in Ne and 1% Ne in D-2 an intense emission band was observed. The maximum intensity was observed for 10% D-2 in Ne. Comparisons...... with results from gas phase measurements indicate that the dominant component of the band originates from a bound-free transition from the A(2) Sigma(+) state of NeD to the repulsive ground state....

  3. Differential Mobility Spectrometry-Hydrogen Deuterium Exchange (DMS-HDX) as a Probe of Protein Conformation in Solution

    Science.gov (United States)

    Zhu, Shaolong; Campbell, J. Larry; Chernushevich, Igor; Le Blanc, J. C. Yves; Wilson, Derek J.

    2016-03-01

    Differential mobility spectrometry (DMS) is an ion mobility technique that has been adopted chiefly as a pre-filter for small- to medium-sized analytes (mobility spectroscopy (FAIMS)—the application of DMS to intact biomacromolecules remains largely unexplored. In this work, we employ DMS combined with gas-phase hydrogen deuterium exchange (DMS-HDX) to probe the gas-phase conformations generated from proteins that were initially folded, partially-folded, and unfolded in solution. Our findings indicate that proteins with distinct structural features in solution exhibit unique deuterium uptake profiles as function of their optimal transmission through the DMS. Ultimately we propose that DMS-HDX can, if properly implemented, provide rapid measurements of liquid-phase protein structural stability that could be of use in biopharmaceuticals development.

  4. Differential Mobility Spectrometry-Hydrogen Deuterium Exchange (DMS-HDX) as a Probe of Protein Conformation in Solution

    Science.gov (United States)

    Zhu, Shaolong; Campbell, J. Larry; Chernushevich, Igor; Le Blanc, J. C. Yves; Wilson, Derek J.

    2016-06-01

    Differential mobility spectrometry (DMS) is an ion mobility technique that has been adopted chiefly as a pre-filter for small- to medium-sized analytes (mobility spectroscopy (FAIMS)—the application of DMS to intact biomacromolecules remains largely unexplored. In this work, we employ DMS combined with gas-phase hydrogen deuterium exchange (DMS-HDX) to probe the gas-phase conformations generated from proteins that were initially folded, partially-folded, and unfolded in solution. Our findings indicate that proteins with distinct structural features in solution exhibit unique deuterium uptake profiles as function of their optimal transmission through the DMS. Ultimately we propose that DMS-HDX can, if properly implemented, provide rapid measurements of liquid-phase protein structural stability that could be of use in biopharmaceuticals development.

  5. Double exposure specklegrams obtained by using scaled aperture pupils

    OpenAIRE

    Angel-Toro, Luciano; Tebaldi, Myrian; Trivi, Marcelo; Bolognini, N??stor

    2001-01-01

    In speckle photography the pupil aperture is usually not modified between exposures. In our work, the change of the pupil aperture scale between exposures is analyzed on the basis of double-exposed image speckle, before and after a diffuse in-plane displacement is done. The apertures have the same shape but its scale is modified between exposures. Note that the relative position of the aperture is maintained. In particular, we analyze a simple case that uses a circular aperture whose diameter...

  6. Aperture effects in squid jet propulsion.

    Science.gov (United States)

    Staaf, Danna J; Gilly, William F; Denny, Mark W

    2014-05-01

    Squid are the largest jet propellers in nature as adults, but as paralarvae they are some of the smallest, faced with the inherent inefficiency of jet propulsion at a low Reynolds number. In this study we describe the behavior and kinematics of locomotion in 1 mm paralarvae of Dosidicus gigas, the smallest squid yet studied. They swim with hop-and-sink behavior and can engage in fast jets by reducing the size of the mantle aperture during the contraction phase of a jetting cycle. We go on to explore the general effects of a variable mantle and funnel aperture in a theoretical model of jet propulsion scaled from the smallest (1 mm mantle length) to the largest (3 m) squid. Aperture reduction during mantle contraction increases propulsive efficiency at all squid sizes, although 1 mm squid still suffer from low efficiency (20%) because of a limited speed of contraction. Efficiency increases to a peak of 40% for 1 cm squid, then slowly declines. Squid larger than 6 cm must either reduce contraction speed or increase aperture size to maintain stress within maximal muscle tolerance. Ecological pressure to maintain maximum velocity may lead them to increase aperture size, which reduces efficiency. This effect might be ameliorated by nonaxial flow during the refill phase of the cycle. Our model's predictions highlight areas for future empirical work, and emphasize the existence of complex behavioral options for maximizing efficiency at both very small and large sizes. PMID:24501132

  7. Large-aperture subwavelength grating couplers.

    Science.gov (United States)

    Qi, Fan; Ma, Qingyan; Wang, Yufei; Zheng, Wanhua

    2016-04-10

    Subwavelength nanostructure grating couplers fabricated on silicon-on-insulator substrates are used to simplify the fabrication process while maintaining high coupling efficiency. The main obstacle for their application in photonic integrated circuits is the small aperture size of the nanostructure when TE polarization is involved, since they are difficult to achieve with 193 nm deep-ultraviolet lithography and cause problems in inductively coupled plasma etching. A larger lateral period has been used to increase the aperture size. Here, we propose that decreasing the effective index of the nanostructure can also enlarge the aperture size. We analyze the two methods in detail with a rectangle-hole nanostructure and 220 nm thick waveguide layer, aiming at TE polarization centered at 1560 nm. We find performance degenerations for large lateral periods, and this can be simply compensated by adjusting the width of the rectangle hole. The minimum linewidth of the nanostructure can reach 240 nm, while the coupling efficiency is just slightly decreased. The backreflections of a large-aperture grating increase but stay in the same order with ordinary ones, and we also show that this can be overcome by apodizing the grating structure. Finally, we experimentally demonstrate the designed large-aperture grating couplers and the coupling efficiencies are higher than 35%, and reach a rectangle-hole width. PMID:27139860

  8. SSC [Superconducting Super Collider] aperture workshop summary

    International Nuclear Information System (INIS)

    The SSC Aperture Workshop was held November 5-9, 1984 at Lawrence Berkeley Laboratory. The workshop focused on issues related to the selection of an optimum aperture for the SSC. Aperture is a critical issue at this early stage of design, because it strongly affects both the construction cost and the satisfactory commissioning and operation of the collider. The workshop had a double purpose: To design a course of action for determining the needed physical and dynamic aperture and commensurate magnetic field specifications of a high luminosity proton collider with a beam energy of 20 TeV, and to prepare a proposal for carrying out the recommended R ampersand D program in two steps -- a four-month intensive phase to provide knowledge essential for conceptual design and magnet selection, and a longer term effort to supply details and ultimately to support the construction, commissioning, and operation of the new collider. To accomplish these objectives, the participants met in the following working groups, each led by a coordinator, which are discussed in this paper: test lattices; aperture requirements; magnet errors; formats, data bases, networks and lattice codes; tracking codes; analytical screening; and experiments on existing machines

  9. Deuterium (2H) Distribution in surface and groundwaters in Brazil

    International Nuclear Information System (INIS)

    Evaporation and condensation processes cause variation in the relative concentrations of hydrogen and oxygen isotopes. In the case of hydrogen, variations of the order of 3500/oo were observed in deuterium concentrations in natural waters. In heavy water production plants, wherever possible, water with high deuterium content should be used in the first stages of the enrichment process. Taking this into consideration, work was carried out on the systematic collection of samples from surface and groundwaters for the analysis of deuterium all over Brasil. Deuterium concentration values were obtained in 458 samples collected at different regions and at different times. This project was developed together with others of hydrological interest, the final objective of which was not to cover all characteristic regions of the country. (Author)

  10. Selective Deuterium Ion Acceleration Using the Vulcan PW Laser

    CERN Document Server

    Krygier, AG; Kar, S; Ahmed, H; Alejo, A; Clarke, R; Fuchs, J; Green, A; Jung, D; Kleinschmidt, A; Najmudin, Z; Nakamura, H; Norreys, P; Notley, M; Oliver, M; Roth, M; Vassura, L; Zepf, M; Borghesi, M; Freeman, RR

    2015-01-01

    We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison, et al., \\cite{Morrison:POP2012} an ion beam with $>$99$\\%$ deuterium ions and peak energy 28 MeV is produced with a 200 J, 700fs, $>10^{20} W/cm^{2}$ laser pulse by cryogenically freezing heavy water (D$_{2}$O) vapor onto the rear surface of the target prior to the shot. The estimated total yield of deuterium ions in an assumed 10$^{\\circ}$ half-angle cone was 3.0 $\\mu$C (1.9 $\\times 10^{13}$ ions) with 6.6$\\%$ laser-to-deuterium ion energy conversion efficiency.

  11. Deuterium depleted water. Current and potential applications

    International Nuclear Information System (INIS)

    Deuterium depleted water (DDW) is distilled, microbiologically pure water with a D/(D+H) isotopic content lower than the value 145 ppm of natural water. It is practically unnoxious, with a toxic potential pT 50 > 0.01 mol/kg c.m. At ICSI a procedure was worked out and patented and a facility was achieved for obtaining DDW. The procedure consists in continuous vacuum distillation of natural water on columns with highly performing ordered packings. DDW of controlled isotopic concentration D/(D+H) within the range 20-120 ppm, of quality similar to distilled water can be currently produced. Many studies were reported in literature evidencing the active biological properties of DDW. DDW lowered significantly the high division rate of the L929 linear fibroblast cell and blocked the tumoral growth in xenotransplants. It was suggested that the naturally occurring deuterium plays a prominent role in converting the signal implied in cellular cycle mechanism. Having in view the high significance of the experiments in this field, ICSI has promoted a programme of collaborations with Romanian institutes of various specialties to evaluate the biological effects of DDW with a D/(D+H) concentration of about 30 ppm. The following results obtained so far obtained should be highlighted: - DDW causes an increase of vascular reactivity both in rings isolated from thorax aorta and in vivo upon arterial pressure. The reactivity increase seems to be endothelium-depended and is achieved with participation of the radical species (superoxides, nitric oxide); - DDW stimulates the immunodefence reaction, as represented by the opsonic, bactericide and phagocytic capacity of the immunity system as well as by the increase of the number of polymorphonucleates; - animals pre-treated with DDW exhibit an increased resistance both to sublethal and lethal γ radiation doses, what suggests a radioprotective effect; - studies on artificial fecundation in fishes with fecundant solutions containing a 1

  12. Gaseous exchange reaction of deuterium between hydrogen and water on hydrophobic catalyst supporting platinum

    International Nuclear Information System (INIS)

    The deuterium exchange reaction between hydrogen and water in the gas phase where the fed hydrogen gas is saturated with water vapor is studied experimentally by use of the proper hydrophobic catalysts supporting platinum. It is found that the activities of those catalysts for this reaction system are very high compared with the other known ones for the systems in which gas and liquid should coexist on catalyst surfaces, and that the apparent catalytic activity becomes larger as the amount of platinum supported on a catalyst particle increases. By analyses of the data the following informations are obtained. The exchange reaction can be expressed by a first order reversible reaction kinetics. The pore diffusion in the catalyst particles has significant effect on the overall reaction mechanisms. (author)

  13. Chemical response of lithiated graphite with deuterium irradiation

    OpenAIRE

    Taylor, C N; B. Heim; Allain, Jean Paul

    2011-01-01

    Lithium wall conditioning has been found to enhance plasma performance for graphite walled fusion devices such as TFTR, CDX-U, T-11M, TJ-II and NSTX. Among observed plasma enhancements is a reduction in edge density and reduced deuterium recycling. The mechanism by which lithiated graphite retains deuterium is largely unknown. Under controlled laboratory conditions, X-ray photoelectron spectroscopy (XPS) is used to observe the chemical changes that occur on ATJ graphite after lithium depositi...

  14. Confinement and heating of a deuterium-tritium plasma

    International Nuclear Information System (INIS)

    The Tomamak Fusion Test reactor has performed initial high-power experiments with the plasma fueled with nominally equal densities of deuterium and tritium. Compared to pure deuterium plasmas, the energy stored in the electron and ions increased by ∼20%. These increases indicate improvements in confinement associated with the use of tritium and possibly heating of electrons by α particles created by the D-T fusion reactions

  15. Is deuterium in high-redshift Lyman limit systems primordial?

    International Nuclear Information System (INIS)

    Detections of deuterium in high-redshift Lyman limit absorption systems along the line of sight to QSOs promise to reveal the primordial deuterium abundance. At present, the deuterium abundances (D/H) derived from the very few systems observed are significantly discordant. Assuming the validity of all the data, if this discordance does not reflect intrinsic primordial inhomogeneity, then it must arise from processes operating after the primordial nucleosynthesis epoch. We consider processes that might lead to significant deuterium production or destruction and yet allow the cloud to mimic a chemically unevolved system. These processes include, for example, anomalous/stochastic chemical evolution and D/4He photodestruction. In general, we find it unlikely that these processes could have significantly altered D/H in Lyman limit clouds. We argue that chemical evolution scenarios, unless very finely tuned, cannot account for significant local deuterium depletion since they tend to overproduce 12C, even when allowance is made for possible outflow. Similarly, D/4He photodestruction schemes engineered to locally produce or destroy deuterium founder on the necessity of requiring an improbably large γ-ray source density. Future observations of D/H in Lyman limit systems may provide important insight into the initial conditions for the primordial nucleosynthesis process, early chemical evolution, and the galaxy formation process. copyright 1997 The American Astronomical Society

  16. Deuterium thermal desorption from FeAl thin films

    International Nuclear Information System (INIS)

    Deuterium thermal desorption experiments were performed on B2 FeAl thin films deposited by electron-beam evaporation on Si substrates, annealed at temperatures ranging from 673 to 773 K and implanted with 20 keV D2 ions at fluences of 3x1016 D2+ cm-2. D2 desorption spectra, recorded in isochronal heating conditions (0.5 K s-1 temperature ramp), show two well resolved desorption peaks at ∼500 and 820 K. The first peak is attributed to the desorption of deuterium contained in FeAl weakly bonding sites of the FeAl lattice, probably point defects (vacancies) produced by the ion implantation process. The second peak is attributed to deuterium release from trapping sites in the FeAl lattice that could be the defect complexes formed by the association of a vacancy in the Fe sublattice and a substitutional Fe atom in the Al sublattice (VFe-FeAl). The desorption kinetics can be reproduced by assuming that: (a) deuterium desorption at ∼500 K is controlled by the D2 surface recombination process with Edes=1.57±0.02 eV as activation energy; (b) deuterium desorption at ∼820 K is controlled by the release of D atoms from the trap sites, a process which occurs in connection with defect relaxation. The energy of interaction of deuterium with this trapping site can be estimated to be ∼2 eV. (author)

  17. Advanced Deuterium Fusion Rocket Propulsion for Manned Deep Space Missions

    Science.gov (United States)

    Winterberg, F.

    Excluding speculations about future breakthrough discoveries in physics, it is shown that with what is at present known, and also what is technically feasible, manned space flight to the limits of the solar system and beyond deep into the Oort cloud is quite possible. Using deuterium as the rocket fuel of choice, abundantly available on the comets of the Oort cloud, rockets driven by deuterium fusion can there be refuelled. To obtain a high thrust with high specific impulse favours the propulsion by deuterium micro-bombs, and it is shown that the ignition of deuterium micro-bombs is possible by intense GeV proton beams, generated in space by using the entire spacecraft as a magnetically insulated billion volt capacitor. The cost to develop this kind of a propulsion system in space would be very high, but it can also be developed on Earth by a magnetically insulated Super Marx Generator. Since the ignition of deuterium is theoretically possible with the Super Marx Generator, making obsolete the ignition of deuterium-tritium with a laser, where 80% of the energy goes into neutrons, this would also mean a breakthrough in fusion research, and therefore would justify the large development costs.

  18. Advanced Deuterium Fusion Rocket Propulsion For Manned Deep Space Missions

    CERN Document Server

    Winterberg, Dr Friedwardt

    2009-01-01

    Excluding speculations about future breakthrough discoveries in physics, it is shown that with what is at present known, and also what is technically feasible, manned space flight to the limits of the solar system and beyond deep into the Oort cloud is quite well possible. Using deuterium as the rocket fuel of choice, abundantly available on the comets of the Oort cloud, rockets driven by deuterium fusion, can there be refueled. To obtain a high thrust with a high specific impulse, favors the propulsion by deuterium micro-bombs, and it is shown that the ignition of deuterium micro-bombs is possible by intense GeV proton beams, generated in space by using the entire spacecraft as a magnetically insulated billion volt capacitor. The cost to develop this kind of propulsion system in space would be very high, but it can also be developed on earth by a magnetically insulated Super Marx Generator. Since the ignition of deuterium is theoretically possible with the Super Marx Generator, rather than deuterium-tritium ...

  19. Solar energy apparatus with apertured shield

    Science.gov (United States)

    Collings, Roger J. (Inventor); Bannon, David G. (Inventor)

    1989-01-01

    A protective apertured shield for use about an inlet to a solar apparatus which includesd a cavity receiver for absorbing concentrated solar energy. A rigid support truss assembly is fixed to the periphery of the inlet and projects radially inwardly therefrom to define a generally central aperture area through which solar radiation can pass into the cavity receiver. A non-structural, laminated blanket is spread over the rigid support truss in such a manner as to define an outer surface area and an inner surface area diverging radially outwardly from the central aperture area toward the periphery of the inlet. The outer surface area faces away from the inlet and the inner surface area faces toward the cavity receiver. The laminated blanket includes at least one layer of material, such as ceramic fiber fabric, having high infra-red emittance and low solar absorption properties, and another layer, such as metallic foil, of low infra-red emittance properties.

  20. Optimization of Synthetic Aperture Image Quality

    DEFF Research Database (Denmark)

    Moshavegh, Ramin; Jensen, Jonas; Villagómez Hoyos, Carlos Armando;

    2016-01-01

    Synthetic Aperture (SA) imaging produces high-quality images and velocity estimates of both slow and fast flow at high frame rates. However, grating lobe artifacts can appear both in transmission and reception. These affect the image quality and the frame rate. Therefore optimization of parameters...... F-number, number of emissions and the aperture size. They are considered to be the most contributing acquisition factors in the quality of the high resolution images in SA. Therefore, the performance of image quality is quantified in terms of full-width at half maximum (FWHM) and the cystic...... resolution (CTR). The results of the study showed that SA imaging with only 32 emissions and maximum sweep angle of 22 degrees yields a very good image quality compared with using 256 emissions and the full aperture size. Therefore the number of emissions and the maximum sweep angle in the SA can be...

  1. Deuterium retention in the carbon co-deposition layers deposited by magnetron sputtering in D2/He atmosphere

    International Nuclear Information System (INIS)

    Carbon was deposited on Si and W substrates using a D2/He plasma in a radio frequency magnetron sputtering system. The deposited layers were examined with ion beam analysis (IBA), Raman spectra analysis (RS) and scanning electron microscopy (SEM). The growth rate of the layers deposited at 2.5 Pa total pressure and 300 K decreased with increasing He fraction in the D2/He gas mixture. The deuterium concentration in the layers deposited on the Si substrate increased from 14% to 28% when the flow rate of the He gas relative to the D2 gas was varied from 0.125 to 0.5, but the deuterium concentration in the layers on a W substrate decreased from 24% to 14%. Deuterium or helium retention and the layer thickness all significantly decreased when the substrate temperature was increased from 423 K to 773 K. Raman analysis showed that the deposited layers were amorphous deuterated-carbon layers (named a-C: D layer) and the extent of bond disorder increased dramatically with the increasing helium content in the film. Blisters and bubbles occurred in the films for high helium content in the films, and surface cracking and exfoliation were also observed

  2. The Initial Conditions of Clustered Star Formation III. The Deuterium Fractionation of the Ophiuchus B2 Core

    CERN Document Server

    Friesen, R K; Myers, P C; Belloche, A; Shirley, Y L; Bourke, T L; André, P

    2010-01-01

    We present N2D+ 3-2 (IRAM) and H2D+ 1_11 - 1_10 and N2H+ 4-3 (JCMT) maps of the small cluster-forming Ophiuchus B2 core in the nearby Ophiuchus molecular cloud. In conjunction with previously published N2H+ 1-0 observations, the N2D+ data reveal the deuterium fractionation in the high density gas across Oph B2. The average deuterium fractionation R_D = N(N2D+)/N(N2H+) ~ 0.03 over Oph B2, with several small scale R_D peaks and a maximum R_D = 0.1. The mean R_D is consistent with previous results in isolated starless and protostellar cores. The column density distributions of both H2D+ and N2D+ show no correlation with total H2 column density. We find, however, an anticorrelation in deuterium fractionation with proximity to the embedded protostars in Oph B2 to distances >= 0.04 pc. Destruction mechanisms for deuterated molecules require gas temperatures greater than those previously determined through NH3 observations of Oph B2 to proceed. We present temperatures calculated for the dense core gas through the eq...

  3. Equations of state for hydrogen and deuterium.

    Energy Technology Data Exchange (ETDEWEB)

    Kerley, Gerald Irwin (Kerley Technical Services, Appomattox, VA)

    2003-12-01

    This report describes the complete revision of a deuterium equation of state (EOS) model published in 1972. It uses the same general approach as the 1972 EOS, i.e., the so-called 'chemical model,' but incorporates a number of theoretical advances that have taken place during the past thirty years. Three phases are included: a molecular solid, an atomic solid, and a fluid phase consisting of both molecular and atomic species. Ionization and the insulator-metal transition are also included. The most important improvements are in the liquid perturbation theory, the treatment of molecular vibrations and rotations, and the ionization equilibrium and mixture models. In addition, new experimental data and theoretical calculations are used to calibrate certain model parameters, notably the zero-Kelvin isotherms for the molecular and atomic solids, and the quantum corrections to the liquid phase. The report gives a general overview of the model, followed by detailed discussions of the most important theoretical issues and extensive comparisons with the many experimental data that have been obtained during the last thirty years. Questions about the validity of the chemical model are also considered. Implications for modeling the 'giant planets' are also discussed.

  4. What controls deuterium excess in global precipitation?

    Directory of Open Access Journals (Sweden)

    S. Pfahl

    2014-04-01

    Full Text Available The deuterium excess (d of precipitation is widely used in the reconstruction of past climatic changes from ice cores. However, its most common interpretation as moisture source temperature cannot directly be inferred from present-day water isotope observations. Here, we use a new empirical relation between d and near-surface relative humidity (RH together with reanalysis data to globally predict d of surface evaporation from the ocean. The very good quantitative agreement of the predicted hemispherically averaged seasonal cycle with observed d in precipitation indicates that moisture source relative humidity, and not sea surface temperature, is the main driver of d variability on seasonal timescales. Furthermore, we review arguments for an interpretation of long-term palaeoclimatic d changes in terms of moisture source temperature, and we conclude that there remains no sufficient evidence that would justify to neglect the influence of RH on such palaeoclimatic d variations. Hence, we suggest that either the interpretation of d variations in palaeorecords should be adapted to reflect climatic influences on RH during evaporation, in particular atmospheric circulation changes, or new arguments for an interpretation in terms of moisture source temperature will have to be provided based on future research.

  5. Deuterium enrichment of the interstellar grain mantle

    Science.gov (United States)

    Das, Ankan; Sahu, Dipen; Majumdar, Liton; Chakrabarti, Sandip K.

    2016-01-01

    We carry out Monte Carlo simulation to study deuterium enrichments of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C, CH3, CH2D, OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ˜2 × 104 cm-3), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (˜106 cm-3), water and methanol productions are suppressed but surface coverages of CO, CO2, O2 and O3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high fractionation of methanol but surprisingly water fractionation is found to be low. This is in contradiction with our model results indicating alternative routes for de-fractionation of water. Effects of various types of energy barriers are also studied. Moreover, we allow grain mantles to interact with various charged particles (such as H+, Fe+, S+ and C+) to study the stopping power and projected range of these charged particles on various target ices.

  6. Deuterium enrichment of the interstellar grain mantle

    CERN Document Server

    Das, Ankan; Chakrabarti, Sandip K

    2015-01-01

    We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud regions, very strong radiation fields persists and hardly a few layers of surface species are formed. In translucent cloud regions with a moderate radiation field, significant number of layers would be produced and surface coverage is mainly dominated by photo-dissociation products such as, C,CH_3,CH_2D,OH and OD. In the intermediate dense cloud regions (having number density of total hydrogen nuclei in all forms ~ 2 x 10^4 cm^-3), water and methanol along with their deuterated derivatives are efficiently formed. For much higher density regions (~ 10^6 cm^-3), water and methanol productions are suppressed but surface coverage of CO,CO_2,O_2,O_3 are dramatically increased. We find a very high degree of fractionation of water and methanol. Observational results support a high frac...

  7. Large aperture calorimeter for fusion laser measurements

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, J.G.; Smith, P.A.

    The authors designed and constructed a large aperture calorimeter intended for laser fusion measurements on beams up to 20 cm diameter. The laser beam is absorbed in a glass disc backed by a disc carry a resistance wire. Although it performs essentially as expected with a noise equivalent energy of 20 mJ and a maximum energy of about 100 J, difficulties in construction give a 17% variation of sensitivity across the aperture. To overcome this problem it would probably be necessary to adopt an integral construction with the resistance bridge formed from an etched film on the back of the absorbing glass.

  8. Synthetic aperture radar capabilities in development

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The Imaging and Detection Program (IDP) within the Laser Program is currently developing an X-band Synthetic Aperture Radar (SAR) to support the Joint US/UK Radar Ocean Imaging Program. The radar system will be mounted in the program`s Airborne Experimental Test-Bed (AETB), where the initial mission is to image ocean surfaces and better understand the physics of low grazing angle backscatter. The Synthetic Aperture Radar presentation will discuss its overall functionality and a brief discussion on the AETB`s capabilities. Vital subsystems including radar, computer, navigation, antenna stabilization, and SAR focusing algorithms will be examined in more detail.

  9. Multi-antenna synthetic aperture radar

    CERN Document Server

    Wang, Wen-Qin

    2013-01-01

    Synthetic aperture radar (SAR) is a well-known remote sensing technique, but conventional single-antenna SAR is inherently limited by the minimum antenna area constraint. Although there are still technical issues to overcome, multi-antenna SAR offers many benefits, from improved system gain to increased degrees-of-freedom and system flexibility. Multi-Antenna Synthetic Aperture Radar explores the potential and challenges of using multi-antenna SAR in microwave remote sensing applications. These applications include high-resolution imaging, wide-swath remote sensing, ground moving target indica

  10. A Method for Synthetic Aperture Compounding

    DEFF Research Database (Denmark)

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2010-01-01

    An approach to perform ultrasound spatial compounding using synthetic aperture data is proposed. The approach allows compounding to be performed for any number of directions without reducing the frame rate or temporal resolution. It is demonstrated how the contrast is improved by compounding and...... obtained when using 5 images. Using the same RF data, a synthetic aperture image without compounding reveals a CNR of -0.36, -0.93, -1.23, and -1.61 dB for the four cysts, respectively....

  11. Water drives the deuterium content of the methane emitted from plants

    Science.gov (United States)

    Vigano, I.; Holzinger, R.; Keppler, F.; Greule, M.; Brand, W. A.; Geilmann, H.; van Weelden, H.; Röckmann, T.

    2010-07-01

    plants via the gas phase. Despite these deficiencies, the results suggest that the deuterium content of the methane generated from plants under UV irradiation is closely linked to δD in precipitation. This dependency, which should also exist for other biogenic methane sources could be evaluated with global isotope models.

  12. IMPROVED SYNTHETIC APERTURE SONAR MOTION COMPENSATION COMBINED DPCA WITH SUB-APERTURE IMAGE CORRELATION

    Institute of Scientific and Technical Information of China (English)

    Liu Wei; Zhang Chunhua; Liu Jiyuan

    2009-01-01

    Estimation precision of Displaced Phase Center Algorithm (DPCA) is affected by the number of displaced phase center pairs, the bandwidth of transmitting signal and many other factors. Detailed analysis is made on DPCA's estimation precision. Analysis results show that the directional vector estimation precision of DPCA is low, which will produce accumulating errors when phase centers' track is estimated. Because of this reason, DPCA suffers from accumulating errors seriously. To overcome this problem, a method combining DPCA with Sub Aperture Image Correlation (SAIC) is presented. Large synthetic aperture is divided into sub-apertures. Micro errors in sub-aperture are estimated by DPCA and compensated to raw echo data. Bulk errors between sub-apertures are estimated by SAIC and compensated directly to sub-aperture images. After that, sub-aperture images are directly used to generate ultimate SAS image. The method is applied to the lake-trial dataset of a 20 kHz SAS prototype system. Results show the method can successfully remove the accumulating error and produce a better SAS image.

  13. Compared studies of natural and artificial deuterium depleted water

    International Nuclear Information System (INIS)

    The biological influence of the deuterium on animals was studied insensitively in the last years. When animal cell cultures were analyzed it turned out an inhibition of the development, due to the reduced deuterium concentration. In the in vivo experiments a decreasing of the number of tumoral cells was pointed out when performing the depleted water treatment. It is obvious that the presence of deuterium in water is necessary for the development, especially for the tumoral cell proliferation. The aim of this work was to establish influence of the natural and artificial deuterium depleted water on the vegetal organisms development. For this purpose, the developmental stages of Lactuca sativa L. growth were followed. The experimental data were compared with the data obtained with distilled water. The birch, wine sap and some fruit juices are considered 'natural depleted' water sources because their deuterium content is smaller in comparison to natural water (D2=150 ppm). The effect of artificial deuterium depleted water (29 ppm D2) was analyzed in comparison to three types of wine saps, which also have a reduced deuterium concentration (125-130 ppm D2). If the deuterium depleted water was used, the germination percent and the root and shoot length were higher compared to control in the first stages. In wine sap it had a negative effect on germination and development. After three days the plants were transferred to soil and their development was followed. The foliage area was larger for all of the experimental variants compared to control. The differences were without significance when deuterium depleted water was tested but they were high and very significant in case of wine sap. The experiment pointed out a stimulative effect of the artificial deuterium depleted water. In case of wine sap the effect was negative when the contact was direct, but the growth was stimulated after the stress cessation. The first ontogenetic stages were represented by direct action on

  14. Deuterium Retention and Physical Sputtering of Low Activation Ferritic Steel

    Science.gov (United States)

    T, Hino; K, Yamaguchi; Y, Yamauchi; Y, Hirohata; K, Tsuzuki; Y, Kusama

    2005-04-01

    Low activation materials have to be developed toward fusion demonstration reactors. Ferritic steel, vanadium alloy and SiC/SiC composite are candidate materials of the first wall, vacuum vessel and blanket components, respectively. Although changes of mechanical-thermal properties owing to neutron irradiation have been investigated so far, there is little data for the plasma material interactions, such as fuel hydrogen retention and erosion. In the present study, deuterium retention and physical sputtering of low activation ferritic steel, F82H, were investigated by using deuterium ion irradiation apparatus. After a ferritic steel sample was irradiated by 1.7 keV D+ ions, the weight loss was measured to obtain the physical sputtering yield. The sputtering yield was 0.04, comparable to that of stainless steel. In order to obtain the retained amount of deuterium, technique of thermal desorption spectroscopy (TDS) was employed to the irradiated sample. The retained deuterium desorbed at temperature ranging from 450 K to 700 K, in the forms of DHO, D2, D2O and hydrocarbons. Hence, the deuterium retained can be reduced by baking with a relatively low temperature. The fluence dependence of retained amount of deuterium was measured by changing the ion fluence. In the ferritic steel without mechanical polish, the retained amount was large even when the fluence was low. In such a case, a large amount of deuterium was trapped in the surface oxide layer containing O and C. When the fluence was large, the thickness of surface oxide layer was reduced by the ion sputtering, and then the retained amount in the oxide layer decreased. In the case of a high fluence, the retained amount of deuterium became comparable to that of ferritic steel with mechanical polish or SS 316L, and one order of magnitude smaller than that of graphite. When the ferritic steel is used, it is required to remove the surface oxide layer for reduction of fuel hydrogen retention. Ferritic steel sample was

  15. Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion.

    Science.gov (United States)

    Tanabe, Katsuaki

    2016-01-01

    We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies. PMID:27441240

  16. Theoretical modelling of deuterium ICRF wall conditioning discharges

    International Nuclear Information System (INIS)

    Ion cyclotron conditioning (ICC) discharges are produced by injecting ICRF power to a gas target in the presence of magnetic fields. They have low electron temperature, moderate density and their ion energy distributions show high ion energy tails. ICC has high wall conditioning efficiency and since it is operated with energized magnetic fields, in contrast to glow discharges, they are a promising technique for first wall conditioning of superconducting reactors. Additionally, deuterium ICC has been proposed for reducing the tritium inventory of the first wall of reactors through surface isotope exchange and more recently to etch carbon deposits by adding small amounts of oxygen. Consequently ICC should be further developed as a routine wall conditioning technique for ITER and besides making further experimental progress in its first wall conditioning efficiency, it is also necessary to study the physics of ICC plasmas. This is the objective of this paper, which focuses on the atomic and molecular reactions in ICC plasmas, on the resulting ion and neutral species concentrations and on the ion and electron energy distributions. From the particle and power balance the electron and ion energy is deduced and compared with the experimental results. Estimations of the ion confinement time indicate, that energetic ions do not reach thermal equilibration, which explains the formation of suprathermal tails. The concentration of D, D+, D+2 and D+3 is calculated with a 0D model and found to be strongly dependent on the discharge conditions. Dissociative recombination of molecular ions with electrons and charge exchange reaction of ions with neutrals strongly determine the particle and power balance. The limitations and possible error sources of the results of the theoretical modelling presented here are critically discussed

  17. Shock timing measurements and analysis in deuterium-tritium-ice layered capsule implosions on NIF

    International Nuclear Information System (INIS)

    Recent advances in shock timing experiments and analysis techniques now enable shock measurements to be performed in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility (NIF). Previous measurements of shock timing in inertial confinement fusion implosions [Boehly et al., Phys. Rev. Lett. 106, 195005 (2011); Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] were performed in surrogate targets, where the solid DT ice shell and central DT gas were replaced with a continuous liquid deuterium (D2) fill. These previous experiments pose two surrogacy issues: a material surrogacy due to the difference of species (D2 vs. DT) and densities of the materials used and a geometric surrogacy due to presence of an additional interface (ice/gas) previously absent in the liquid-filled targets. This report presents experimental data and a new analysis method for validating the assumptions underlying this surrogate technique. Comparison of the data with simulation shows good agreement for the timing of the first three shocks, but reveals a considerable discrepancy in the timing of the 4th shock in DT ice layered implosions. Electron preheat is examined as a potential cause of the observed discrepancy in the 4th shock timing

  18. Shock timing measurements and analysis in deuterium-tritium-ice layered capsule implosions on NIF

    Energy Technology Data Exchange (ETDEWEB)

    Robey, H. F.; Celliers, P. M.; Moody, J. D.; Sater, J.; Parham, T.; Kozioziemski, B.; Dylla-Spears, R.; Ross, J. S.; LePape, S.; Ralph, J. E.; Dewald, E. L.; Berzak Hopkins, L.; Kroll, J. J.; Yoxall, B. E.; Hamza, A. V.; Landen, O. L.; Edwards, M. J. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Hohenberger, M.; Boehly, T. R. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Nikroo, A. [General Atomics, San Diego, California 92196 (United States)

    2014-02-15

    Recent advances in shock timing experiments and analysis techniques now enable shock measurements to be performed in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility (NIF). Previous measurements of shock timing in inertial confinement fusion implosions [Boehly et al., Phys. Rev. Lett. 106, 195005 (2011); Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] were performed in surrogate targets, where the solid DT ice shell and central DT gas were replaced with a continuous liquid deuterium (D2) fill. These previous experiments pose two surrogacy issues: a material surrogacy due to the difference of species (D2 vs. DT) and densities of the materials used and a geometric surrogacy due to presence of an additional interface (ice/gas) previously absent in the liquid-filled targets. This report presents experimental data and a new analysis method for validating the assumptions underlying this surrogate technique. Comparison of the data with simulation shows good agreement for the timing of the first three shocks, but reveals a considerable discrepancy in the timing of the 4th shock in DT ice layered implosions. Electron preheat is examined as a potential cause of the observed discrepancy in the 4th shock timing.

  19. Shock timing measurements and analysis in deuterium-tritium-ice layered capsule implosions on NIF

    Science.gov (United States)

    Robey, H. F.; Celliers, P. M.; Moody, J. D.; Sater, J.; Parham, T.; Kozioziemski, B.; Dylla-Spears, R.; Ross, J. S.; LePape, S.; Ralph, J. E.; Hohenberger, M.; Dewald, E. L.; Berzak Hopkins, L.; Kroll, J. J.; Yoxall, B. E.; Hamza, A. V.; Boehly, T. R.; Nikroo, A.; Landen, O. L.; Edwards, M. J.

    2014-02-01

    Recent advances in shock timing experiments and analysis techniques now enable shock measurements to be performed in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility (NIF). Previous measurements of shock timing in inertial confinement fusion implosions [Boehly et al., Phys. Rev. Lett. 106, 195005 (2011); Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] were performed in surrogate targets, where the solid DT ice shell and central DT gas were replaced with a continuous liquid deuterium (D2) fill. These previous experiments pose two surrogacy issues: a material surrogacy due to the difference of species (D2 vs. DT) and densities of the materials used and a geometric surrogacy due to presence of an additional interface (ice/gas) previously absent in the liquid-filled targets. This report presents experimental data and a new analysis method for validating the assumptions underlying this surrogate technique. Comparison of the data with simulation shows good agreement for the timing of the first three shocks, but reveals a considerable discrepancy in the timing of the 4th shock in DT ice layered implosions. Electron preheat is examined as a potential cause of the observed discrepancy in the 4th shock timing.

  20. Parametric Beamformer for Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Tomov, Borislav Gueorguiev; Jensen, Jørgen Arendt

    2006-01-01

    In this paper a parametric beamformer, which can handle all imaging modalities including synthetic aperture imaging, is presented. The image lines and apodization coefficients are specified parametrically, and the lines can have arbitrary orientation and starting point in 3D coordinates. The beam...

  1. Vowel Aperture and Syllable Segmentation in French

    Science.gov (United States)

    Goslin, Jeremy; Frauenfelder, Ulrich H.

    2008-01-01

    The theories of Pulgram (1970) suggest that if the vowel of a French syllable is open then it will induce syllable segmentation responses that result in the syllable being closed, and vice versa. After the empirical verification that our target French-speaking population was capable of distinguishing between mid-vowel aperture, we examined the…

  2. Perceiving Affordances for Fitting through Apertures

    Science.gov (United States)

    Ishak, Shaziela; Adolph, Karen E.; Lin, Grace C.

    2008-01-01

    Affordances--possibilities for action--are constrained by the match between actors and their environments. For motor decisions to be adaptive, affordances must be detected accurately. Three experiments examined the correspondence between motor decisions and affordances as participants reached through apertures of varying size. A psychophysical…

  3. Synthetic Aperture Beamformation using the GPU

    DEFF Research Database (Denmark)

    Hansen, Jens Munk; Schaa, Dana; Jensen, Jørgen Arendt

    2011-01-01

    A synthetic aperture ultrasound beamformer is implemented for a GPU using the OpenCL framework. The implementation supports beamformation of either RF signals or complex baseband signals. Transmit and receive apodization can be either parametric or dynamic using a fixed F-number, a reference, and a...

  4. Diffraction contrast imaging using virtual apertures

    International Nuclear Information System (INIS)

    Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast. - Highlights: • A dataset containing all structural information of a given position is recorded. • The dataset allows reconstruction of virtual diffraction patterns or images. • Specific virtual apertures are designed to image precipitates in a complex alloy. • Virtual diffraction patterns from arbitrarily small regions can be established. • Using STEM diffraction to record the dataset is more efficient than TEM dark-field

  5. Dynamic metamaterial aperture for microwave imaging

    Science.gov (United States)

    Sleasman, Timothy; F. Imani, Mohammadreza; Gollub, Jonah N.; Smith, David R.

    2015-11-01

    We present a dynamic metamaterial aperture for use in computational imaging schemes at microwave frequencies. The aperture consists of an array of complementary, resonant metamaterial elements patterned into the upper conductor of a microstrip line. Each metamaterial element contains two diodes connected to an external control circuit such that the resonance of the metamaterial element can be damped by application of a bias voltage. Through applying different voltages to the control circuit, select subsets of the elements can be switched on to create unique radiation patterns that illuminate the scene. Spatial information of an imaging domain can thus be encoded onto this set of radiation patterns, or measurements, which can be processed to reconstruct the targets in the scene using compressive sensing algorithms. We discuss the design and operation of a metamaterial imaging system and demonstrate reconstructed images with a 10:1 compression ratio. Dynamic metamaterial apertures can potentially be of benefit in microwave or millimeter wave systems such as those used in security screening and through-wall imaging. In addition, feature-specific or adaptive imaging can be facilitated through the use of the dynamic aperture.

  6. Parametric Transverse Patterns in Broad Aperture Lasers

    DEFF Research Database (Denmark)

    Grigorieva, E.V.; Kashchenko, S.A.; Mosekilde, Erik

    1998-01-01

    Parametrically generated optical patterns are investigated for finite and large-scale transverse aperture lasers. Standing and rotating patterns as well as periodic and chaotic pattern alternations are described in the framework of the amplitude equation formalism. Sensitive dependence on the...... geometrical size of the system is demonstrated even in the case of large-scale systems....

  7. Dynamic metamaterial aperture for microwave imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sleasman, Timothy; Imani, Mohammadreza F.; Gollub, Jonah N.; Smith, David R. [Center for Metamaterials and Integrated Plasmonics, Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, 27708 (United States)

    2015-11-16

    We present a dynamic metamaterial aperture for use in computational imaging schemes at microwave frequencies. The aperture consists of an array of complementary, resonant metamaterial elements patterned into the upper conductor of a microstrip line. Each metamaterial element contains two diodes connected to an external control circuit such that the resonance of the metamaterial element can be damped by application of a bias voltage. Through applying different voltages to the control circuit, select subsets of the elements can be switched on to create unique radiation patterns that illuminate the scene. Spatial information of an imaging domain can thus be encoded onto this set of radiation patterns, or measurements, which can be processed to reconstruct the targets in the scene using compressive sensing algorithms. We discuss the design and operation of a metamaterial imaging system and demonstrate reconstructed images with a 10:1 compression ratio. Dynamic metamaterial apertures can potentially be of benefit in microwave or millimeter wave systems such as those used in security screening and through-wall imaging. In addition, feature-specific or adaptive imaging can be facilitated through the use of the dynamic aperture.

  8. Analytic inversion in synthetic aperture radar.

    OpenAIRE

    Rothaus, O. S.

    1994-01-01

    A method of processing synthetic aperture radar signals that avoids some of the approximations currently in use that appear to be responsible for severe phase distortions is described. As a practical matter, this method requires N3 numerical operations, as opposed to the N2 ln N currently the case, but N3 is now easily managed, for N in the range of interest.

  9. Experiences on synthetic aperture focussing technique (SAFT)

    International Nuclear Information System (INIS)

    Imaging based on the synthetic aperture focussing technique (SAFT) improves the reliability of sizing and characterisation of structural discontinuities found in non-destructive testing of nuclear components. One of the main advantages of this technique is an improvement of signal-to-noise-ratio. The advantages are discussed in terms of practical applications and theory. (orig.)

  10. Compound imaging using Synthetic Aperture Sequential Beamformation

    DEFF Research Database (Denmark)

    Jensen, Casper Bo; Jensen, Jonas; Hemmsen, Martin Christian;

    2011-01-01

    Synthetic Aperture Sequential Beamforming (SASB) is a technique with low complexity and the ability to yield a more uniform lateral resolution with range. However, the presence of speckle artifacts in ultrasound images degrades the contrast. In conventional imaging speckle is reduced by using...

  11. Interferometric Synthetic Aperture Microwave Radiometers : an Overview

    Science.gov (United States)

    Colliander, Andreas; McKague, Darren

    2011-01-01

    This paper describes 1) the progress of the work of the IEEE Geoscience and Remote Sensing Society (GRSS) Instrumentation and Future Technologies Technical Committee (IFT-TC) Microwave Radiometer Working Group and 2) an overview of the development of interferometric synthetic aperture microwave radiometers as an introduction to a dedicated session.

  12. Synthetic Aperture Imaging in Medical Ultrasound

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Gammelmark, Kim; Pedersen, Morten;

    2004-01-01

    Synthetic Aperture (SA) ultrasound imaging is a relatively new and unexploited imaging technique. The images are perfectly focused both in transmit and receive, and have a better resolution and higher dynamic range than conventional ultrasound images. The blood flow can be estimated from SA images...

  13. A Tensor Polarized Deuterium Internal Target

    Science.gov (United States)

    Zhou, Z.-L.; Ferro-Luzzi, M.; Bulten, H. J.; den Brand, Van; Lang, J.

    1996-10-01

    A tensor polarized deuterium internal target and its polarimetry are presented. A beam of approximately 2×10^16 atoms/s, produced in an atomic beam source (ABS), is fed into a cooled Teflon-coated storage cell internally to the AmPS electron storage ring at NIKHEF. Target thickness of about 2×10^13 atoms/cm^2 has been achieved, which correspondes to a luminosity of 10^31 atoms/cm^2s at beam currents of 100 mA. The tensor polarization of the atomic beam is rapidly switched between maximal values by using RF transitions in the ABS. The target spin axis can be oriented flexibly in the scattering plane of the experiment with a 30 mT B-field. The atomic beam intensity and polarization are monitored by a Breit-Rabi polarimeter. The absolute target polarization is determined in-situ with an ion polarimeter to an accuracy better than 5%. Ions produced in the storage cell by circulating electrons are extracted from the beam line using a set of electrostatic lenses and a spherical deflector, and then mass-analyzed with a Wien filter to determine the target atomic-to-molecular fraction. P_zz^±(D^+) are consequently measured by using the ^3H(d,n)α reaction. The target has been used in an experiment to measure tensor analyzing powers in e-d elastic and (e,e^'p) scattering. Future upgrades to higher luminosities are planned.

  14. A solid-deuterium source of ultra-cold neutrons at the FRM-II

    International Nuclear Information System (INIS)

    Ultra-cold neutrons (UCN) will be produced at the new high-flux reactor FRM-II at Garching near Munich in a solid-deuterium storage source (Mini-D2). The UCN density in this source is expected to be nearly three orders of magnitude larger than that reached in the up-to-now strongest UCN source (at Institut Laue-Langevin in Grenoble). The scheme of Mini-D2 is simple: a small cylindrical volume (diameter about 6 cm, length 9 cm) with solid deuterium, the converter, is coupled to a large cylindrical evacuated storage tube with Be-coated walls (diameter also 6 cm, length about 7 m). The source will be installed with the converter very close to the cold source of FRM-II and the core-far end of the storage tube already outside the moderator tank. Solid deuterium at temperatures around 5 K is a good converter. The UCN production rate from cold neutrons is large, the absorption cross section small (in the mbarn/atom region for 40-K neutrons), and the up-scattering cross-section at 5 K even smaller. Most of the UCN produced in the converter leave it into the storage tube before being up-scattered or absorbed. The losses in the tube, mainly by up-scattering or absorption at the Be-coated walls, are small, as its temperature is kept at about 25 K. The energy band of the neutrons in the tube reaches from 100 neV, the energy a neutron gains when it leaves the deuterium, to about 250 neV, the maximum energy for total reflection at the Be-coated walls. With a cold-neutron flux of 3x1013 cm-2s-1 at the place of Mini-D2 we expect UCN densities of about 5x104 cm-3 and a corresponding UCN flux of about 3x106 cm-2s-1, when the end of the storage tube is opened to an experimental set-up. The solid-deuterium in the converter will be produced by deposition of deuterium gas on the 5-K converter walls. As the storage tube is kept at 25 K, the amount of solid deuterium deposited on its walls is small. The necessary cooling power for the source, about 160 W at the 5-K level and 400 W at 25 K

  15. Deuterium absorption from the D2O exposure of oxidized 4H-SiC (0001), (0001¯), and (112¯0) surfaces

    International Nuclear Information System (INIS)

    We report results on deuterium absorption on several oxidized 4H-SiC surfaces following D2O vapor absorption. Absorption at the oxide/semiconductor interface is strongly face dependent with an order of magnitude more deuterium on the C-face and a-face than on the Si-face, in contrast to the bulk of the oxides which show essentially no face dependence. Annealing in NO gas produces a large reduction in interfacial deuterium absorption in all cases. The reduction of the positive charge at the interface scales linearly with the interface D content. These results also scale with the variation in interface trap density (Dit) and mobility on the three faces after wet oxidation annealing

  16. Cavity-excited Huygens' metasurface antennas: near-unity aperture efficiency from arbitrarily-large apertures

    CERN Document Server

    Epstein, Ariel; Eleftheriades, George V

    2015-01-01

    One of the long-standing problems in antenna engineering is the realization of highly-directive beams using low-profile devices. In this paper we provide a solution to this problem by means of Huygens' metasurfaces (HMSs), based on the equivalence principle. This principle states that a given excitation can be transformed to a desirable aperture field by inducing suitable electric and magnetic surface currents. Building on this concept, we propose and demonstrate cavity-excited HMS antennas, where the single-source cavity excitation is designed to optimize aperture illumination, while the HMS facilitates the current distribution that ensures phase purity of aperture fields. The HMS breaks the coupling between the excitation and radiation spectrum typical to standard partially-reflecting surfaces, allowing tailoring of the aperture properties to produce a desirable radiation pattern. As shown, a single semianalytical formalism can be followed to achieve control of a variety of radiation features, such as the d...

  17. Study of the pd→→n{pp}s charge-exchange reaction using a polarised deuterium target

    Directory of Open Access Journals (Sweden)

    B. Gou

    2015-02-01

    Full Text Available The vector and tensor analysing powers, Ay and Ayy, of the pd→→n{pp}s charge-exchange reaction have been measured at a beam energy of 600 MeV at the COSY-ANKE facility by using an unpolarised proton beam incident on an internal storage cell target filled with polarised deuterium gas. The low energy recoiling protons were measured in a pair of silicon tracking telescopes placed on either side of the target. Putting a cut of 3 MeV on the diproton excitation energy ensured that the two protons were dominantly in the S01 state, here denoted by {pp}s. The polarisation of the deuterium gas was established through measurements in parallel of proton–deuteron elastic scattering. By analysing events where both protons entered the same telescope, the charge-exchange reaction was measured for momentum transfers q≥160 MeV/c. These data provide a good continuation of the earlier results at q≤140 MeV/c obtained with a polarised deuteron beam. They are also consistent with impulse approximation predictions with little sign evident for any modifications due to multiple scatterings. These successful results confirm that the ANKE deuteron charge-exchange programme can be extended to much higher energies with a polarised deuterium target than can be achieved with a polarised deuteron beam.

  18. Selected bibliography on deuterium isotope effects and heavy water

    International Nuclear Information System (INIS)

    In recent years, there has been a great deal of interest in using deuterium and heavy water not only in nuclear industry but also in various fields of basic as well as applied research in physics, chemistry and biology. As a result, the literature is being enriched with a large number of research papers and technical reports published each year. Thus, to enable the scientists to have an easy reference to these works, an endeavour has been made in this selected bibliography, to enlist the publications related to these fields. Since the interest is concerned mainly with heavy water production processes, deuterium isotope effects etc., several aspects (e.g. nuclear) of deuterium have not been covered here. The material in this bibliography which cites 2388 references has been classified under six broad headings, viz. (1) Production of heavy water, (2) Study of deuterium isotope effects, (3) Analysis and Properties of heavy water, (4) Laser Separation of deuterium, (5) Isotopic exchange reactions, and (6) Miscellaneous. The sources of information used for this compilation are chemical abstracts, nuclear science abstracts, INIS Atomindex and also some scattered search through journals and reports available in the B.A.R.C. library. However, in spite of sincere attempts for a wide coverage, no claim is being made towards the exhaustiveness of this bibliography. (author)

  19. Radioprotective and Immunostimulating Effects of Deuterium-Depleted Water

    International Nuclear Information System (INIS)

    Full text: Mice fed during 15 days with Deuterium-Depleted Water (30 ppm deuterium) had a statistically significant increased survival compared with control groups fed with normal distilled water (150 ppm deuterium) after 8.5 Gy irradiation (61% survival in test group towards 25% in control group). Hematological picture showed maintaining of the normal WBC, RBC and platelet count in test groups. Immunological parameters (serum opsonic and bactericidal capacity, bactericidal capacity of the peritoneal macrophages) showed a marked increase in test groups compared to a severe decrease in the control groups. Auxiliary tests using chemical radiomimetics (hydrochloric embihine) and immunosupressors (cyclophosphamide) showed a strong protective effect of deuterium-depleted water against the decrease of the leukocyte counts and other immunologic parameters. In conditions of experimental inflammation with subcutaneous-implanted pellets, deuterium-depleted water feeding statistically significant increased inflammatory response, obviated by increased percentages of PMN and lymphocytes in the peripheral blood and increased phagocytic capacity of the peripheral blood PMN. Experimental infections with K. pneumoniae 506 and S. pneumoniae 558 in mice irradiated or treated with cyclophosphamide showed increased non-specific immunity parameters. All results show a marked intensification of the immune defenses and increased proliferation of the peripheral blood cells, probably accounting for the radioprotective effects. (author)

  20. Modeling AXAF Obstructions with the Generalized Aperture Program.

    Science.gov (United States)

    Nguyen, D.; Gaetz, T.; Jerius, D.; Stern, I.

    The generalized aperture program is designed to simulate the effects on the incident photon stream of physical obstructions, such as thermal baffles and pre- and post-collimators. It can handle a wide variety of aperture shapes, and has provisions to allow alterations of the photons by the apertures. The philosophy behind the aperture program is that a geometrically complicated aperture may be modeled by a combination of geometrically simpler apertures. This is done by incorporating a language, lua, to lay out the apertures. User provided call-back functions enable the modeling of the interactions of the incident photon with the apertures. This approach allows for maximum flexibility, since the geometry and interactions of obstructions can be specified by the user at run time.

  1. Intense deuterium nuclear fusion of pycnodeuterium-lumps coagulated locally within highly deuterated atom clusters

    International Nuclear Information System (INIS)

    Embedded nano-Pd particles of 5 nm in size instantly abundant D-atoms more than 250% in the atomic ratio against Pd-atoms at room temperature when they are kept in D2 gas pressurized to less than 10 atm. In such ultrahigh densities, 2-4 D-atoms can be coagulated inside each octahedral space of Pd lattice (pycnodeuterium-lump). When a stimulation energy such as latticequake causing by ultrasonic wave was supplied to those highly deuterated Pd particles, intense deuterium nuclear fusion (''solid fusion'') was generated there and both excess heat and 4He gas were abundantly produced. Naturally, these facts can not be realized at all in bulk Pd. The results show that the nuclear fusion occurs without any hazardous rays in pycnodeuterium-lumps coagulated locally inside the each cell of the host metal lattice. These unit cells correspond to minimum unit of the solid fusion reactor as a ''Lattice Reactor''. (author)

  2. Deuterium plasma-material wall interactions. Final report, 1 May 1979-30 September 1981

    International Nuclear Information System (INIS)

    During the final year of this program we completed our study of plasma interactions with material surfaces. Analysis of unipolar arc damage on the microstructure of Ti-6Al-4V was the final part of the study of plasma-metal interactions. Unipolar arcing was found to be the most severe damage mechanism for this alloy and the degree of damage was very sensitive to the metal microstructure. ATJ-S graphite specimens were exposed to hot deuterium plasma and were examined for surface damage. The residual gas in the plasma device was studied using a monopole gas analyzer so as to determine the type and quantity of hydrocarbon species produced by the plasma-graphite interaction

  3. Intense deuterium nuclear fusion of pycnodeuterium-lumps coagulated locally within highly deuterated atom clusters

    CERN Document Server

    Yoshiaki, A; Zhang, Y C

    2002-01-01

    Embedded nano-Pd particles of 5 nm in size instantly abundant D-atoms more than 250% in the atomic ratio against Pd-atoms at room temperature when they are kept in D sub 2 gas pressurized to less than 10 atm. In such ultrahigh densities, 2-4 D-atoms can be coagulated inside each octahedral space of Pd lattice (pycnodeuterium-lump). When a stimulation energy such as latticequake causing by ultrasonic wave was supplied to those highly deuterated Pd particles, intense deuterium nuclear fusion (''solid fusion'') was generated there and both excess heat and sup 4 He gas were abundantly produced. Naturally, these facts can not be realized at all in bulk Pd. The results show that the nuclear fusion occurs without any hazardous rays in pycnodeuterium-lumps coagulated locally inside the each cell of the host metal lattice. These unit cells correspond to minimum unit of the solid fusion reactor as a ''Lattice Reactor''. (author)

  4. Coded-aperture imaging using photo-induced reconfigurable aperture arrays for mapping terahertz beams

    CERN Document Server

    Kannegulla, Akash; Rahman, Syed; Fay, Patrick; Xing, Huili Grace; Cheng, Li-Jing; Liu, Lei

    2013-01-01

    We report terahertz coded-aperture imaging using photo-induced reconfigurable aperture arrays on a silicon wafer. The coded aperture was implemented using programmable illumination from a commercially available digital light processing projector. At 590 GHz, each of the array element apertures can be optically turned on and off with a modulation depth of 20 dB and a modulation rate of ~1.3 KHz. Prototype demonstrations of 4 by 4 coded-aperture imaging using Hadamard coding have been performed and this technique has been successfully applied to mapping THz beams by using a 6 by 6 aperture array at 590 GHz. The imaging results agree closely with theoretical calculations based on Gaussian beam transformation, demonstrating that this technique is promising for realizing real-time and low-cost terahertz cameras for many applications. The reported approach provides a simple but powerful means to visualize THz beams, which is highly desired in quasi-optical system alignment, quantum-cascade laser design and characte...

  5. Wide-aperture electric-discharge nitrogen laser

    International Nuclear Information System (INIS)

    The parameters of a wide-aperture nitrogen laser pumped by a generator with the inductive energy storage and a SOS diode opening switch or a generator with the capacitive energy storage are studied. The gas preionisation was performed by soft X-rays. The size of the active volume of the laser was 10x6x100 cm. The output energy and power obtained at the 337.1-nm C 3Πu - B 3Πg transition are maximal for electric-discharge nitrogen lasers. The output energy in the second positive system of nitrogen in the N2-SF6 mixture achieved 110 mJ for a peak power of 6 MW. Due to an increase in voltage across the laser gap in nitrogen mixtures with NF3, the generation of ∼35-mJ, 100-ns pulses was obtained in the quasi-stationary stage of the discharge. (lasers)

  6. Warm water deuterium fractionation in IRAS 16293-2422. The high-resolution ALMA and SMA view

    DEFF Research Database (Denmark)

    Persson, Magnus Vilhelm; Jørgensen, J. K.; van Dishoeck, E. F.

    2013-01-01

    Context. Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength...... interferometers have the potential to shed light on this matter. Aims: To measure the water deuterium fractionation in the warm gas of the deeply-embedded protostellar binary IRAS 16293-2422. Methods: Observations toward IRAS 16293-2422 of the 53,2 - 44,1 transition of H218O at 692.07914 GHz from Atacama Large...... observations reveal the physical and chemical structure of water vapor close to the protostars on solar-system scales. The red-shifted absorption detected toward source B is indicative of infall. The excitation temperature is consistent with the picture of water ice evaporation close to the protostar. The low...

  7. Multi-static synthetic aperture radar and inverse scattering

    OpenAIRE

    Gustafsson, Mats

    2004-01-01

    In this paper synthetic aperture radar is analyzed from an inverse scattering perspective. It is shown that the classical point scattering model can be generalized to a dipole scattering model. The dipole scattering model reduces to the point scattering model for small aperture angles. For large aperture angles or multiple illumination apertures the dipole model gives an anisotropic reflectivity such that orthogonal scattering processes are separated. Moreover, it is shown th...

  8. Deuterium migration in nuclear graphite: Consequences for the behavior of tritium in CO2-cooled reactors and for the decontamination of irradiated graphite waste

    Science.gov (United States)

    Le Guillou, M.; Toulhoat, N.; Pipon, Y.; Moncoffre, N.; Khodja, H.

    2015-06-01

    In this paper, we aim at understanding tritium behavior in the graphite moderator of French CO2-cooled nuclear fission reactors (called UNGG for "Uranium Naturel-Graphite-Gaz") to get information on its distribution and inventory in the irradiated graphite waste after their dismantling. These findings should be useful both to improve waste treatment processes and to foresee tritium behavior during reactor decommissioning and waste disposal operations. The purpose of the present work is to elucidate the effects of temperature on the behavior of tritium during reactor operation. Furthermore, it aims at exploring options of thermal decontamination. For both purposes, annealing experiments were carried out in inert atmosphere as well as in thermal conditions as close as possible to those encountered in UNGG reactors and in view of a potential decontamination in humid gas. D+ ions were implanted into virgin nuclear graphite in order to simulate tritium displaced from its original structural site through recoil during reactor operation. The effect of thermal treatments on the mobility of the implanted deuterium was then investigated at temperatures ranging from 200 to 1200 °C, in inert atmosphere (vacuum or argon), in a gas simulating the UNGG coolant gas (mainly CO2) or in humid nitrogen. Deuterium was analyzed by Nuclear Reaction Analysis (NRA) both at millimetric and micrometric scales. We have identified three main stages for the deuterium release. The first one corresponds to deuterium permeation through graphite open pores. The second and third ones are controlled by the progressive detrapping of deuterium located at different trapping sites and its successive migration through the crystallites and along crystallites and coke grains edges. Extrapolating the thermal behavior of deuterium to tritium, the results show that the release becomes significant above the maximum UNGG reactor temperature of 500 °C and should be lower than 30% of the total amount produced

  9. Deuterium migration in nuclear graphite: Consequences for the behavior of tritium in CO{sub 2}-cooled reactors and for the decontamination of irradiated graphite waste

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, M. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Agence nationale pour la gestion des déchets radioactifs, DRD/CM – 1-7, rue Jean Monnet, Parc de la Croix-Blanche, F-92298 Châtenay-Malabry cedex (France); Toulhoat, N., E-mail: nelly.toulhoat@univ-lyon1.fr [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); CEA/DEN – Centre de Saclay, F-91191 Gif-sur-Yvette cedex (France); Pipon, Y. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Institut Universitaire Technologique, Université Claude Bernard Lyon 1, Université de Lyon – 43, boulevard du 11 novembre 1918, F-69622 Villeurbanne cedex (France); Moncoffre, N. [Institut de Physique Nucléaire de Lyon, CNRS/IN2P3 UMR 5822, Université Claude Bernard Lyon 1, Université de Lyon – 4, rue Enrico Fermi, F-69622 Villeurbanne cedex (France); Khodja, H. [Laboratoire d’Etude des Eléments Légers, CEA/DSM/IRAMIS/NIMBE, UMR 3299 SIS2M – Centre de Saclay, F-91191 Gif-sur-Yvette cedex (France)

    2015-06-15

    In this paper, we aim at understanding tritium behavior in the graphite moderator of French CO{sub 2}-cooled nuclear fission reactors (called UNGG for “Uranium Naturel-Graphite-Gaz”) to get information on its distribution and inventory in the irradiated graphite waste after their dismantling. These findings should be useful both to improve waste treatment processes and to foresee tritium behavior during reactor decommissioning and waste disposal operations. The purpose of the present work is to elucidate the effects of temperature on the behavior of tritium during reactor operation. Furthermore, it aims at exploring options of thermal decontamination. For both purposes, annealing experiments were carried out in inert atmosphere as well as in thermal conditions as close as possible to those encountered in UNGG reactors and in view of a potential decontamination in humid gas. D{sup +} ions were implanted into virgin nuclear graphite in order to simulate tritium displaced from its original structural site through recoil during reactor operation. The effect of thermal treatments on the mobility of the implanted deuterium was then investigated at temperatures ranging from 200 to 1200 °C, in inert atmosphere (vacuum or argon), in a gas simulating the UNGG coolant gas (mainly CO{sub 2}) or in humid nitrogen. Deuterium was analyzed by Nuclear Reaction Analysis (NRA) both at millimetric and micrometric scales. We have identified three main stages for the deuterium release. The first one corresponds to deuterium permeation through graphite open pores. The second and third ones are controlled by the progressive detrapping of deuterium located at different trapping sites and its successive migration through the crystallites and along crystallites and coke grains edges. Extrapolating the thermal behavior of deuterium to tritium, the results show that the release becomes significant above the maximum UNGG reactor temperature of 500 °C and should be lower than 30% of the

  10. A dosimetry study of deuterium-deuterium neutron generator-based in vivo neutron activation analysis

    Science.gov (United States)

    Sowers, Daniel A.

    A neutron irradiation cavity for in vivo Neutron Activation Analysis (IVNAA) to detect manganese, aluminum, and other potentially toxic elements in human hand bone has been designed and its dosimetric specifications measured. The neutron source is a customized deuterium-deuterium neutron generator which produces neutrons at 2.45 MeV by the fusion reaction 2H(d, n)3He at a calculated flux of 7 x 108 +/-30% s-1. A moderator/reflector/shielding (5 cm high density polyethylene (HDPE), 5.3 cm graphite & 5.7 cm borated HDPE) assembly has been designed and built to maximize the thermal neutron flux inside the hand irradiation cavity and to reduce the extremity dose and effective dose to the human subject. Lead sheets are used to attenuate bremsstrahlung x rays and activation gammas. A Monte Carlo simulation (MCNP6) was used to model the system and calculate extremity dose. The extremity dose was measured with neutron and photon sensitive film badges and Fuji electronic pocket dosimeter (EPD). The neutron ambient dose outside the shielding was measured by Fuji NSN3, and photon dose by a Bicron MicroREM scintillator. Neutron extremity dose was calculated to be 32.3 mSv using MCNP6 simulations given a 10 min IVNAA measurement of manganese. Measurements by EPD and film badge indicate hand dose to be 31.7 +/- 0.8 mSv for neutron and 4.2 +/- 0.2 mSv for photon for 10 mins; whole body effective dose was calculated conservatively to be 0.052 mSv. Experimental values closely match values obtained from MCNP6 simulations. These are acceptable doses to apply the technology for a manganese toxicity study in a human population.

  11. In-vivo examples of synthetic aperture vector flow imaging

    DEFF Research Database (Denmark)

    Oddershede, Niels; Hansen, Kristoffer Lindskov; Nielsen, Michael Bachmann;

    2007-01-01

    would be needed. Synthetic aperture vector flow imaging could potentially provide this. The purpose of this paper is to test the synthetic aperture vector flow imaging method on challenging in-vivo data. Two synthetic aperture in-vivo data sets are acquired using a commercial linear array transducer and...

  12. An optimization algorithm for volumetrically segmented aperture-based IMRT

    International Nuclear Information System (INIS)

    There are few algorithms to create aperture-based IMRT such as Iterative least-square algorithm, Simultaneous projection algorithm (Cimmino's algorithm), Mixed integer programming, etc. In this present work, a Volumetrically Segmented Aperture Optimization (VSAO) algorithm is introduced and its usefulness in generating aperture-based IMRT plans is investigated in different case studies

  13. Measurements of ultracold neutron lifetimes in solid deuterium

    CERN Document Server

    Morris, C L; Bowles, T J; Filippone, B W; Geltenbort, P; Hill, R E; Hino, M; Hoedl, S; Hogan, G E; Ito, T M; Kawai, T; Kirch, K; Lamoreaux, S K; Liu, C Y; Mäkelä, M; Marek, L J; Martin, J W; Mortensen, R N; Pichlmaier, A; Saunders, A; Seestrom, S J; Smith, D; Teasdale, W A; Tipton, B; Utsuro, M; Young, A R; Yuan, J

    2001-01-01

    We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium SD2. This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid ortho-deuterium as the source material. Superthermal UCN sources offer orders of magnitude improvement in the available densities of UCNs, and are of great importance to fundamental particle-physics experiments such as searches for a static electric dipole moment and lifetime measurements of the free neutron. These measurements are performed utilizing a SD2 source coupled to a spallation source of neutrons, providing a demonstration of UCN production in this geometry and permitting systematic studies of the influence of thermal up-scatter and contamination with para-deuterium on the UCN survival time.

  14. Interaction of deuterium with SS316 austenitic stainless steel

    International Nuclear Information System (INIS)

    Accumulation and desorption of deuterium implanted in SS316 austenitic stainless steel to concentrations ∼1 at.%, the influence of helium and radiation-induced defects on the process of mass transfer of deuterium and the mechanical properties of steel at different levels of damage were studied. The samples were irradiated with 15 keV/D, 30 keV/He and 1.4 MeV/Ar ions. For modeling of the defect structure formed in the materials of nuclear power plants, the irradiation with high-energy argon ions was performed. Studies were carried out by means of ion implantation, nuclear reactions D(3He,p)4He with analyzing beam of 3He (E = 0.3...1.4 MeV), thermal desorption spectroscopy, transmission electron microscopy and nanoindentation. It was found that the retention of deuterium in steel is increased significantly in the presence of radiation damage created by helium and argon pre-implantation

  15. Development of neutron spectrometer toward deuterium plasma diagnostics in LHD

    International Nuclear Information System (INIS)

    Neutron spectrometer based on coincident counting of associated particles has been developed for deuterium plasma diagnostics on Large Helical Device (LHD) at the National Institute for Fusion Science. Efficient detection of 2.5 MeV neutron with high energy resolution would be achievable by coincident detection of a scattered neutron and a recoiled proton associated with an elastic scattering of incident neutron in a plastic scintillator as a radiator. The calculated neutron spectra from deuterium plasma heated by neutral beam injection indicate that the energy resolution of better than 7% is required for the spectrometer to evaluate energetic deuterium confinement. By using a prototype of the proposed spectrometer, the energy resolution of 6.3% and the detection efficiency of 3.3x10-7 count/neutron were experimentally demonstrated for 2.5 MeV monoenergetic neutron, respectively.

  16. Hyperfine structure of P-states in muonic deuterium

    CERN Document Server

    Faustov, R N; Martynenko, G A; Sorokin, V V

    2015-01-01

    On the basis of quasipotential approach to the bound state problem in quantum electrodynamics we calculate hyperfine structure intervals Delta E^{hfs}(2P_{1/2}) and Delta E^{hfs}(2P_{3/2}) for P-states in muonic deuterium. The tensor method of projection operators for the calculation of the hyperfine structure of P-states with definite quantum numbers of total atomic momentum F and total muon momentum j in muonic deuterium is formulated. We take into account vacuum polarization, relativistic, quadruple and structure corrections of orders alpha^4, alpha^5 and alpha^6. The obtained numerical values of hyperfine splittings are useful for the analysis of new experimental data of the CREMA collaboration regarding to muonic deuterium.

  17. Carbon and deuterium nuclear magnetic resonance in solids

    International Nuclear Information System (INIS)

    Results are presented on a study of cross polarization dynamics, between protons and carbon-13 in adamantane, by the direct observation of the dilute, carbon-13 spins. A comparison is presented of the experimental and theoretical proton dipolar fluctuation correlation time tau/sub c/, which is experimentally 110 +- 15 μsec and theoretically 122 μsec for adamantane. An approach to high resolution NMR of deuterium in solids is described. The m = 1 → --1 transition is excited by a double quantum process and the decay of coherence Q(tau) is monitored. The carboxyl and the water deuterium shifts are resolved and the anisotropy of the carboxyl shielding tensor is estimated to be Δ sigma = 32 +- ppM. A complete theoretical analysis is presented. The extension of cross relaxation techniques, both direct and indirect, to proton-deuterium double resonance is also described

  18. Deuterium NMR Studies of the Structure and Dynamics of Gramicidin.

    Science.gov (United States)

    Hing, Andrew William

    1990-01-01

    The structure and dynamics of the membrane peptide gramicidin are investigated by deuterium NMR. A specific structural and dynamical question about the peptide backbone of gramicidin is investigated by deuterating the alpha carbon of the third alanine residue. Deuterium NMR experiments performed on this analog in oriented lipid bilayers indicate that the c_alpha- ^2H bond makes an angle relative to the helical axis that is in agreement with the bond angle predicted by the beta^{6.3} helical model. A second structural and dynamical question about the peptide backbone of gramicidin is investigated by deuterating the formyl group of two different analogs. Deuterium NMR experiments performed on these analogs show that the spectra of the two analogs are very similar. However, the analog possessing D-leucine as the second residue also appears to exist in a second, minor conformation which does not seem to exist for the analog possessing glycine as the second residue.

  19. High Gain, Very Low Areal Density, Scalable RF Apertures Enabled by Membrane Aperture Shell Technology (MAST) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose that the Membrane Aperture Shell Technology (MAST) approach be expanded with a specific focus on space exploration orbiting comm network RF aperture...

  20. Deuterium thermal desorption from FeAl thin films

    Energy Technology Data Exchange (ETDEWEB)

    Checchetto, R. [Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Fisica dell' Universita di Trento, Povo (Italy)]. E-mail: checchet@science.unitn.it; Miotello, A.; Tosello, C. [Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Fisica dell' Universita di Trento, Povo (Italy); Principi, G. [Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Ingegneria Meccanica e Strutturale dell' Universita di Padova, Padova (Italy); Mengucci, P. [Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio dell' Universita di Ancona, Ancona (Italy)

    2002-07-01

    Deuterium thermal desorption experiments were performed on B2 FeAl thin films deposited by electron-beam evaporation on Si substrates, annealed at temperatures ranging from 673 to 773 K and implanted with 20 keV D{sub 2} ions at fluences of 3x10{sup 16} D{sub 2}{sup +} cm{sup -2}. D{sub 2} desorption spectra, recorded in isochronal heating conditions (0.5 K s{sup -1} temperature ramp), show two well resolved desorption peaks at {approx}500 and 820 K. The first peak is attributed to the desorption of deuterium contained in FeAl weakly bonding sites of the FeAl lattice, probably point defects (vacancies) produced by the ion implantation process. The second peak is attributed to deuterium release from trapping sites in the FeAl lattice that could be the defect complexes formed by the association of a vacancy in the Fe sublattice and a substitutional Fe atom in the Al sublattice (V{sub Fe}-Fe{sub Al}). The desorption kinetics can be reproduced by assuming that: (a) deuterium desorption at {approx}500 K is controlled by the D{sub 2} surface recombination process with E{sub des}=1.57{+-}0.02 eV as activation energy; (b) deuterium desorption at {approx}820 K is controlled by the release of D atoms from the trap sites, a process which occurs in connection with defect relaxation. The energy of interaction of deuterium with this trapping site can be estimated to be {approx}2 eV. (author)

  1. Performance limits for Synthetic Aperture Radar.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2006-02-01

    The performance of a Synthetic Aperture Radar (SAR) system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to ''get your arms around'' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics, no matter how bright the engineer tasked to generate a system design. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall SAR system. For example, there are definite optimum frequency bands that depend on weather conditions and range, and minimum radar PRF for a fixed real antenna aperture dimension is independent of frequency. While the information herein is not new to the literature, its collection into a single report hopes to offer some value in reducing the ''seek time''.

  2. IR aperture measurement at β*=40 cm

    CERN Document Server

    Bruce, Roderik; Hermes, Pascal Dominik; Kwee-Hinzmann, Regina; Mereghetti, Alessio; Mirarchi, Daniele; Redaelli, Stefano; Salvachua Ferrando, Belen Maria; Skowronski, Piotr Krzysztof; Valentino, Gianluca; Valloni, Alessandra; CERN. Geneva. ATS Department

    2015-01-01

    This note summarizes MD 307, performed on August 27 2015, during which we measured with beam the global apertures at 6.5 TeV with IR1 and IR5 squeezed to β* =40 cm and a half crossing angle of 205 rad. The measurement technique involved opening collimators in steps, while inducing beam losses at each step, until the main loss location moved from the collimators to the global bottleneck in one of the triplets. Measurements were performed in both beams and planes, and each measurement gave the minimum triplet aperture over IR1 and IR5. The results are in very good agreement with theoretical predictions. At the end of the MD, an asynchronous beam dump test was performed with all collimators moved in to so-called 2-σ retraction settings. This MD is one in a series meant to address various open points for the reach in β* in Run II.

  3. Polarization-sensitive interferometric synthetic aperture microscopy

    Science.gov (United States)

    South, Fredrick A.; Liu, Yuan-Zhi; Xu, Yang; Shemonski, Nathan D.; Carney, P. Scott; Boppart, Stephen A.

    2015-11-01

    Three-dimensional optical microscopy suffers from the well-known compromise between transverse resolution and depth-of-field. This is true for both structural imaging methods and their functional extensions. Interferometric synthetic aperture microscopy (ISAM) is a solution to the 3D coherent microscopy inverse problem that provides depth-independent transverse resolution. We demonstrate the extension of ISAM to polarization sensitive imaging, termed polarization-sensitive interferometric synthetic aperture microscopy (PS-ISAM). This technique is the first functionalization of the ISAM method and provides improved depth-of-field for polarization-sensitive imaging. The basic assumptions of polarization-sensitive imaging are explored, and refocusing of birefringent structures is experimentally demonstrated. PS-ISAM enables high-resolution volumetric imaging of birefringent materials and tissue.

  4. Flame Reconstruction Using Synthetic Aperture Imaging

    CERN Document Server

    Murray, Preston; Tree, Dale; Truscott, Tadd

    2011-01-01

    Flames can be formed by burning methane (CH4). When oxygen is scarce, carbon particles nucleate into solid particles called soot. These particles emit photons, making the flame yellow. Later, methane is pre-mixed with air forming a blue flame; burning more efficiently, providing less soot and light. Imaging flames and knowing their temperature are vital to maximizing efficiency and validating numerical models. Most temperature probes disrupt the flame and create differences leading to an inaccurate measurement of the flame temperature. We seek to image the flame in three dimensions using synthetic aperture imaging. This technique has already successfully measured velocity fields of a vortex ring [1]. Synthetic aperture imaging is a technique that views one scene from multiple cameras set at different angles, allowing some cameras to view objects that are obscured by others. As the resulting images are overlapped different depths of the scene come into and out of focus, known as focal planes, similar to tomogr...

  5. High frame rate synthetic aperture duplex imaging

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Pihl, Michael Johannes;

    2013-01-01

    Conventional color flow images are limited in velocity range and can either show the high velocities in systole or be optimized for the lower diastolic velocities. The full dynamics of the flow is, thus, hard to visualize. The dynamic range can be significantly increased by employing synthetic...... aperture flow imaging as demonstrated in this paper. Synthetic aperture, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images at high frame rates. The frame rate equals the effective pulse repetition frequency of each imaging mode. Emissions for making the B...... estimation is −1.8% and the relative standard deviation 5.4%. The approach can thus estimate both high and low velocities with equal accuracy and thereby makes it possible to present vector flow images with a high dynamic range. Measurements are made using the SARUS research scanner, a linear array...

  6. Deuterium isotope effects in propylene and ethylene ozonide

    Energy Technology Data Exchange (ETDEWEB)

    Jong-In Choe; Hyung-Soo Choi; Kuczkowski, R.L.

    1986-12-01

    The proton NMR spectra of four deuteriated species of propylene ozonide and five of ethylene ozonide were analysed. The deuterium isotope shifts were 0.0140 ppm (H gem to D), 0.0034 ppm (H trans to D) and 0.0015 ppm (H cis to D) for propylene ozonide. The same trends were observed in ethylene ozonide. The isotope shifts were not additive when two geminal protons were substituted by deuterium. The relative intensities of microwave rotational and proton NMR transitions were compared for propylene ozonide-d/sub 1/ prepared stereoselectively in order to assign unambiguously its chemical shifts and spin-spin splittings.

  7. Deuterium isotope effects in propylene and ethylene ozonide

    International Nuclear Information System (INIS)

    The proton NMR spectra of four deuteriated species of propylene ozonide and five of ethylene ozonide were analysed. The deuterium isotope shifts were 0.0140 ppm (H gem to D), 0.0034 ppm (H trans to D) and 0.0015 ppm (H cis to D) for propylene ozonide. The same trends were observed in ethylene ozonide. The isotope shifts were not additive when two geminal protons were substituted by deuterium. The relative intensities of microwave rotational and proton NMR transitions were compared for propylene ozonide-d1 prepared stereoselectively in order to assign unambiguously its chemical shifts and spin-spin splittings. (author)

  8. Transport of recycled deuterium to the plasma core in TFTR

    International Nuclear Information System (INIS)

    The authors report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR). They have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. They find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer

  9. Transport of recycled deuterium to the plasma core in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, C.H.; Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Ramsey, A.T.; Stotler, D.P.; Strachan, J.D.

    1997-10-01

    The authors report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR). They have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. They find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.

  10. Transport of Recycled Deuterium to the Plasma Core in TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Bell, M.G.; Budny, R.V.; Jassby, D.L.; Park, H.; Skinner, C.H.; et al

    1997-10-01

    We report a study of the fueling of the plasma core by recycling in the Tokamak Fusion Test Reactor (TFTR) [Phys. Plasmas 2, 2176 (1995)]. We have analyzed discharges fueled by deuterium recycled from the limiter and tritium-only neutral beam injection. In these plasmas, the DT neutron rate provides a measure of the deuterium influx into the core plasma. We find a reduced influx with plasmas using lithium pellet conditioning and with plasmas of reduced major (and minor) radius. Modeling with the DEGAS neutrals code shows that the dependence on radius can be related to the penetration of neutrals through the scrape-off layer.

  11. Deuterium/hydrogen natural isotopic abundance in fruit juices

    International Nuclear Information System (INIS)

    Stable isotopic analyses of various elements such as carbon, hydrogen and oxygen are currently applied for the authentification of naturalness of fruit juices. Deuterium is particularly of interest because of the wide variation of its abundance. Due to evaporation-transpiration the deuterium content of the water in fruit juices is enriched compared to local ground water. In the case of our investigation on apple, another fractionation, originating in technological process, was observed. The concentrated juice water is enriched by 6o/oo as compared to natural fruit juice water. (authors)

  12. Nanostructures of hydrogen- and deuterium-terminated porous silicon

    International Nuclear Information System (INIS)

    We report structure and properties of hydrogen- and deuterium- terminated porous silicon studied with combination of small-angle neutron scattering and small-angle x-ray scattering techniques. All the scattering profiles obtained here are quantitatively well fitted by a model of polydispersed silicon nanocrystal cores with surface terminations. The inner silicon core becomes smaller together with slight expansion of the outer hydrogen or deuterium shell with increasing porosity. However, the type of termination little influences these nanostructures. We discuss the photoluminescence of the porous silicon based on these results. (J.P.N.)

  13. Variable-Aperture Reciprocating Reed Valve

    Science.gov (United States)

    Lindner, Jeffrey L. (Inventor); Myers, W. Neill (Inventor); Kelley, Anthony R. (Inventor); Yang, Hong Q. (Inventor)

    2015-01-01

    A variable-aperture reciprocating reed valve includes a valve body defining a through hole region having a contoured-profile portion. A semi-rigid plate is affixed on one side thereof to the valve body to define a cantilever extending across the through hole region. At least one free edge of the cantilever opposes the contoured-profile portion of the through hole region in a non-contact relationship.

  14. A Tutorial on Synthetic Aperture Radar

    OpenAIRE

    Moreira, Alberto; Prats-Iraola, Pau; Younis, Marwan; Krieger, Gerhard; Hajnsek, Irena; Papathanassiou, Konstantinos

    2013-01-01

    Synthetic Aperture Radar (SAR) has been widely used for Earth remote sensing for more than 30 years. It provides high-resolution, day-and-night and weather-independent images for a multitude of applications ranging from geoscience and climate change research, environmental and Earth system monitoring, 2-D and 3-D mapping, change detection, 4-D mapping (space and time), security-related applications up to planetary exploration. With the advances in radar technology and geo/bio-physical paramet...

  15. Real-time interferometric synthetic aperture microscopy

    OpenAIRE

    Ralston, Tyler S.; Marks, Daniel L.; Carney, P. Scott; Boppart, Stephen A.

    2008-01-01

    An interferometric synthetic aperture microscopy (ISAM) system design with real-time 2D cross-sectional processing is described in detail. The system can acquire, process, and display the ISAM reconstructed images at frame rates of 2.25 frames per second for 512 × 1024 pixel images. This system provides quantitatively meaningful structural information from previously indistinguishable scattering intensities and provides proof of feasibility for future real-time ISAM systems.

  16. Real-time interferometric synthetic aperture microscopy.

    Science.gov (United States)

    Ralston, Tyler S; Marks, Daniel L; Carney, P Scott; Boppart, Stephen A

    2008-02-18

    An interferometric synthetic aperture microscopy (ISAM) system design with real-time 2D cross-sectional processing is described in detail. The system can acquire, process, and display the ISAM reconstructed images at frame rates of 2.25 frames per second for 512 X 1024 pixel images. This system provides quantitatively meaningful structural information from previously indistinguishable scattering intensities and provides proof of feasibility for future real-time ISAM systems. PMID:18542337

  17. Motion compensation of Synthetic Aperture Radar

    OpenAIRE

    Duncan, David; Long, David

    2003-01-01

    Synthetic aperture radar (SAR) is a digital signal processing technique which enhances the azimuth resolution of a radar image using the target doppler history created by the motion of the radar platform. If the platform deviates from a constant velocity, straight-line path then image quality is lost and image details become unfocused. Motion compensation (MOCO) is a technique in which the position and attitude of the platform is recorded or estimated and then used to correct the scene's dopp...

  18. Simultaneous Navigation and Synthetic Aperture Radar Focusing

    OpenAIRE

    Sjanic, Zoran; Gustafsson, Fredrik

    2015-01-01

    Synthetic aperture radar (SAR) equipment is a radar imaging system that can be used to create high-resolution images of a scene by utilizing the movement of a flying platform. Knowledge of the platforms trajectory is essential to get good and focused images. An emerging application field is real-time SAR imaging using small and cheap platforms where estimation errors in navigation systems imply unfocused images. This contribution investigates a joint estimation of the trajectory and SAR image...

  19. Feasibility of Swept Synthetic Aperture Ultrasound Imaging.

    Science.gov (United States)

    Bottenus, Nick; Long, Will; Zhang, Haichong K; Jakovljevic, Marko; Bradway, David P; Boctor, Emad M; Trahey, Gregg E

    2016-07-01

    Ultrasound image quality is often inherently limited by the physical dimensions of the imaging transducer. We hypothesize that, by collecting synthetic aperture data sets over a range of aperture positions while precisely tracking the position and orientation of the transducer, we can synthesize large effective apertures to produce images with improved resolution and target detectability. We analyze the two largest limiting factors for coherent signal summation: aberration and mechanical uncertainty. Using an excised canine abdominal wall as a model phase screen, we experimentally observed an effective arrival time error ranging from 18.3 ns to 58 ns (root-mean-square error) across the swept positions. Through this clutter-generating tissue, we observed a 72.9% improvement in resolution with only a 3.75 dB increase in side lobe amplitude compared to the control case. We present a simulation model to study the effect of calibration and mechanical jitter errors on the synthesized point spread function. The relative effects of these errors in each imaging dimension are explored, showing the importance of orientation relative to the point spread function. We present a prototype device for performing swept synthetic aperture imaging using a conventional 1-D array transducer and ultrasound research scanner. Point target reconstruction error for a 44.2 degree sweep shows a reconstruction precision of 82.8 μm and 17.8 μm in the lateral and axial dimensions respectively, within the acceptable performance bounds of the simulation model. Improvements in resolution, contrast and contrast-to-noise ratio are demonstrated in vivo and in a fetal phantom. PMID:26863653

  20. Optimization of Synthetic Aperture Image Quality

    OpenAIRE

    Moshavegh, Ramin; Jensen, Jonas; Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Hemmsen, Martin Christian; Jensen, Jørgen Arendt

    2016-01-01

    Synthetic Aperture (SA) imaging produces high-quality images and velocity estimates of both slow and fast flow at high frame rates. However, grating lobe artifacts can appear both in transmission and reception. These affect the image quality and the frame rate. Therefore optimization of parameters effecting the image quality of SA is of great importance, and this paper proposes an advanced procedure for optimizing the parameters essential for acquiring an optimal image quality, while generati...

  1. Restoring Aperture Profile At Sample Plane

    International Nuclear Information System (INIS)

    Off-line conditioning of full-size optics for the National Ignition Facility required a beam delivery system to allow conditioning lasers to rapidly raster scan samples while achieving several technical goals. The main purpose of the optical system designed was to reconstruct at the sample plane the flat beam profile found at the laser aperture with significant reductions in beam wander to improve scan times. Another design goal was the ability to vary the beam size at the sample to scan at different fluences while utilizing all of the laser power and minimizing processing time. An optical solution was developed using commercial off-the-shelf lenses. The system incorporates a six meter relay telescope and two sets of focusing optics. The spacing of the focusing optics is changed to allow the fluence on the sample to vary from 2 to 14 Joules per square centimeter in discrete steps. More importantly, these optics use the special properties of image relaying to image the aperture plane onto the sample to form a pupil relay with a beam profile corresponding almost exactly to the flat profile found at the aperture. A flat beam profile speeds scanning by providing a uniform intensity across a larger area on the sample. The relayed pupil plane is more stable with regards to jitter and beam wander. Image relaying also reduces other perturbations from diffraction, scatter, and focus conditions. Image relaying, laser conditioning, and the optical system designed to accomplish the stated goals are discussed

  2. Class of near-perfect coded apertures

    International Nuclear Information System (INIS)

    Coded aperture imaging of gamma ray sources has long promised an improvement in the sensitivity of various detector systems. The promise has remained largely unfulfilled, however, for either one of two reasons. First, the encoding/decoding method produces artifacts, which even in the absence of quantum noise, restrict the quality of the reconstructed image. This is true of most correlation-type methods. Second, if the decoding procedure is of the deconvolution variety, small terms in the transfer function of the aperture can lead to excessive noise in the reconstructed image. It is proposed to circumvent both of these problems by use of a uniformly redundant array (URA) as the coded aperture in conjunction with a special correlation decoding method. It is shown that the reconstructed image in the URA system contains virtually uniform noise regardless of the structure in the original source. Therefore, the improvement over a single pinhole camera will be relatively larger for the brighter points in the source than for the low intensity points. In the case of a large detector background noise the URA will always do much better than the single pinhole regardless of the structure of the object. In the case of a low detector background noise, the improvement of the URA over the single pinhole will have a lower limit of approximately (1/2f)/sup 1/2 / where f is the fraction of the field of view which is uniformly filled by the object

  3. Coded-aperture imaging in nuclear medicine

    Science.gov (United States)

    Smith, Warren E.; Barrett, Harrison H.; Aarsvold, John N.

    1989-01-01

    Coded-aperture imaging is a technique for imaging sources that emit high-energy radiation. This type of imaging involves shadow casting and not reflection or refraction. High-energy sources exist in x ray and gamma-ray astronomy, nuclear reactor fuel-rod imaging, and nuclear medicine. Of these three areas nuclear medicine is perhaps the most challenging because of the limited amount of radiation available and because a three-dimensional source distribution is to be determined. In nuclear medicine a radioactive pharmaceutical is administered to a patient. The pharmaceutical is designed to be taken up by a particular organ of interest, and its distribution provides clinical information about the function of the organ, or the presence of lesions within the organ. This distribution is determined from spatial measurements of the radiation emitted by the radiopharmaceutical. The principles of imaging radiopharmaceutical distributions with coded apertures are reviewed. Included is a discussion of linear shift-variant projection operators and the associated inverse problem. A system developed at the University of Arizona in Tucson consisting of small modular gamma-ray cameras fitted with coded apertures is described.

  4. Large-aperture hybrid photo-detector

    International Nuclear Information System (INIS)

    We have developed the first complete large-aperture (13-inch diameter) hybrid photo-detector (HPD). The withstanding voltage problem has been overcome and we were able to attain an HPD operating voltage of +20 kV. Adoption of our newly developed backside illumination avalanche diode (AD) was also critical in successfully countering the additional problem of an increase in AD leakage after the activation process. We observed single photon signal timing jitter of under 450 ps in FWHM, electron transit time of ∼12 ns, and clear pulse height separation up to several photoelectron peaks, all greatly superior to the performance of any conventional large-aperture photomultiplier tubes (PMTs). In addition, our HPD has a much simpler structure than conventional large-aperture PMTs, which simplifies mass production and lowers manufacturing cost. We believe that these attributes position our HPD as the most suitable photo-detector for the next generation mega-ton class water-Cherenkov detector, which is expected to be more than 20x larger than the Super-Kamiokande (SK) detector

  5. Outdoor synthetic aperture acoustic ground target measurements

    Science.gov (United States)

    Bishop, Steven; Ngaya, Therese-Ann; Vignola, Joe; Judge, John; Marble, Jay; Gugino, Peter; Soumekh, Mehrdad; Rosen, Erik

    2010-04-01

    A novel outdoor synthetic aperture acoustic (SAA) system consists of a microphone and loudspeaker traveling along a 6.3-meter rail system. This is an extension from a prior indoor laboratory measurement system in which selected targets were insonified while suspended in air. Here, the loudspeaker and microphone are aimed perpendicular to their direction of travel along the rail. The area next to the rail is insonified and the microphone records the reflected acoustic signal, while the travel of the transceiver along the rail creates a synthetic aperture allowing imaging of the scene. Ground surfaces consisted of weathered asphalt and short grass. Several surface-laid objects were arranged on the ground for SAA imaging. These included rocks, concrete masonry blocks, grout covered foam blocks; foliage obscured objects and several spherical canonical targets such as a bowling ball, and plastic and metal spheres. The measured data are processed and ground targets are further analyzed for characteristics and features amenable for discrimination. This paper includes a description of the measurement system, target descriptions, synthetic aperture processing approach and preliminary findings with respect to ground surface and target characteristics.

  6. Coded-aperture imaging of the heart

    International Nuclear Information System (INIS)

    Coded-aperture imaging of the heart combines the advantages of tomography with good sensitivity, high resolution, and accurate size scaling. Since the images are multiplexed, the method may be adapted to small, portable cameras for bedside use without sacrificing image resolution. A new coded aperture designed especially for cardiac imaging has been constructed and tested. This aperture incorporates significant improvements over previous designs. Longitudinal tomograms are calculated at 1-cm intervals using a modified ART algorithm. Experimental lateral resolution at 140 keV with a portable scintillation camera is 3.8 mm FWHM at 4 cm, and 7.8 mm FWHM at 12 cm. Depth resolution determined from a sloping line source is 1.1 cm FWHM at 4 cm, and 2.9 cm at 12 cm. The calculated point-source sensitivities in air at 4 cm and 12 cm, respectively, are 20 and 8 cps/μCi. Images of good diagnostic quality have been obtained in phantoms and in a dog model of acute myocardial infarction, using thallium-201, technetium-99m pyrophosphate, and gated ventricular blood-pool imaging with Tc-labeled red blood cells. Preliminary studies in humans confirm the good results in animals

  7. Specific features of X-ray generation by plasma focus chambers with deuterium and deuterium-tritium fillings

    Science.gov (United States)

    Dulatov, A. K.; Krapiva, P. S.; Lemeshko, B. D.; Mikhailov, Yu. V.; Moskalenko, I. N.; Prokuratov, I. A.; Selifanov, A. N.

    2016-01-01

    The process of hard X-ray (HXR) generation in plasma focus (PF) chambers was studied experimentally. The radiation was recorded using scintillation detectors with a high time resolution and thermoluminescent detectors in combination with the method of absorbing filters. Time-resolved analysis of the processes of neutron and X-ray generation in PFs is performed. The spectra of HXR emission from PF chambers with deuterium and deuterium-tritium fillings are determined. In experiments with PF chambers filled with a deuterium-tritium mixture, in addition to the HXR pulse with photon energies of up to 200-300 keV, a γ-ray pulse with photon energies of up to 2.5-3.0 MeV is recorded, and a mechanism of its generation is proposed.

  8. Jacobi-Bessel Analysis Of Antennas With Elliptical Apertures.

    Science.gov (United States)

    Rahmat-Samii, Y.

    1989-01-01

    Coordinate transformation improves convergence pattern analysis of elliptical-aperture antennas. Modified version of Jacobi-Bessel expansion for vector diffraction analysis of reflector antennas uses coordinate transformation to improve convergence with elliptical apertures. Expansion converges rapidly for antennas with circular apertures, but less rapidly for elliptical apertures. Difference in convergence behavior between circular and elliptical Jacobi-Bessel algorithms indicated by highest values of indices m, n, and p required to achieve same accuracy in computed radiation pattern of offset paraboloidal antenna with elliptical aperture.

  9. Cluster speckle structures through multiple apertures forming a closed curve

    Science.gov (United States)

    Mosso, E.; Tebaldi, M.; Lencina, A.; Bolognini, N.

    2010-04-01

    In this work, cluster-like speckle patterns are analyzed. These patterns are generated when a diffuser illuminated by coherent light is imaged by a lens having a pupil mask with multiple apertures forming a closed curve. We show that the cluster structure results from the complex modulation produced inside each speckle which is generated by multiple interferences of light through the apertures. In particular, when the apertures are uniformly distributed along a closed curve, the resulting image speckle cluster replicates the pupil aperture distribution. Experimental results and theoretical simulations show that cluster features depend on the apertures distribution and the size of the closed curves.

  10. Calibration of the TUD Ku-band Synthetic Aperture Radiometer

    DEFF Research Database (Denmark)

    Laursen, Brian; Skou, Niels

    1995-01-01

    The TUD Synthetic Aperture Radiometer is a 2-channel demonstration model that can simulate a thinned aperture radiometer having an unfilled aperture consisting of several small antenna elements. Aperture synthesis obtained by interferometric measurements using the antenna elements in pairs......, followed by an image reconstruction based on an inverse Fourier transform, results in an imaging instrument without the need of mechanical scan. The thinned aperture and the non-scanning feature make the technique attractive for low frequency spaceborne radiometer systems, e.g. at L-band. Initial...

  11. Mass-Spectrometry, a method for determination of deuterium distribution in birds' body under the effect of water with low deuterium content

    International Nuclear Information System (INIS)

    Full text: Deuterium concentration in water is about 144 ppm D/(D + H). Many studies were carried out in order to investigate the influence of water deuterium concentration on the living matter. These studies have demonstrated that while the deuterium normal quantities don't have harmful effects, the increase of deuterium intrinsic concentrations with over 15-20% determine structural, metabolic and functional alterations in different grades, which can lead finally at organism death. At the opposite pole, the general aspect of modifications induced by the administration of deuterium depleted water was the stimulation of cellular reactivity and unspecific impunity, reduction of harmful effects of different noxious agents, noticing also an inhibitor effect on several types of cancer. Referring to the prolongated administration of deuterium depleting medium it was pursued, in the present research, the mode and the grade in which deuterium is exchanged with hydrogen in the mammals organism. The results show that in natural conditions, the organism have the tendency to accumulate deuterium. On the other hand, the grade of deuterium depletion seems to be under the influence both of specimen genotype and behavior, and also of deuterium depleting medium concentration. (author)

  12. Crossed aperture lenses for the correction of chromatic and aperture aberrations

    International Nuclear Information System (INIS)

    The chromatic and aperture aberrations of crossed five-aperture lenses are analyzed by direct ray tracing. The apertures are rectangular and the voltages are applied in such a way that the first-order properties of the crossed lens are similar to those of a quadrupole doublet. It is shown that in astigmatic modes the chromatic and aperture aberrations of one of the linear images can be simultaneously eliminated or made negative. It is also shown that stigmatic modes exist in which the magnification is different in two perpendicular planes and in which the image blurring caused by the chromatic and aperture aberrations in the direction of smaller magnification is ten times smaller than that given by a round lens of the same focal length and the blurring in the other direction is at least two times smaller. The stigmatic crossed lens also gives a larger working distance than the equivalent round lens. The crossed lens will therefore be preferable for many probe forming systems. copyright 1996 American Institute of Physics

  13. Parameters for HL-LHC aperture calculations and comparison with aperture measurements

    CERN Document Server

    Bruce, R; Fartoukh, S; Giovannozzi, M; Redaelli, S; Tomas, R; Wenninger, J

    2014-01-01

    When β∗ is squeezed to smaller values in the LHC, the beam size in the inner triplet increases so that the aperture risks to be exposed to unwanted beam losses. A 2D calculation model was used during the design stage to study the aperture margins, both there and at other potential bottlenecks. Based on assumptions on orbit and optics errors, as well as mechanical tolerances, it gives the available aperture in units of the RMS beam size, which can be compared with what can be protected by the collimation system. During the LHC Run I in 2010-2013, several of the error tolerances have been found smaller than the design assumptions. Furthermore, the aperture has been measured with beam several times and the results are compatible with a very well aligned machine, with results close to the design values. In this report, we therefore review the assumptions in the model and propose an updated set of input parameters to be used for aperture calculations at top energy in HL-LHC. The new parameter set is based on th...

  14. A spectrometrical method to measure the deuterium content in 2H-enriched water

    International Nuclear Information System (INIS)

    A test method and spectrometer has been developed for emission-spectrometrical measurement of the deuterium content in water enriched with deuterium. The water sample is melted into a previously evacuated glas tube and a gas discharge is excited in vapour over the cooled sample to adjust to a low vapour pressure with high frequency. The intensities of the H(α) and D(α) lines appearing in the spectrum determine the D-content. Both lines were resolved by a Fabry-Perot interferometer and geometrically separated fed to two photodetectors. The remaining spectrum is filtered off. Following electronic calculation of the signals, the measured value is indicated which has to be corrected by a standard curve. The relative measuring accuracy is about +-1% for enrichments of over 1% D and less than +-5% in the region of 0.3-1% D. The detection limit is about 0.03% D (sample amount: 50 μl, average of 5 samples). (orig./HP)

  15. Experimental study on anomalous neutron production in deuterium/solid system

    International Nuclear Information System (INIS)

    A series of experiments on both D2O electrolysis and thermal cycle of deuterium absorbed Ti Turnings has been designed to examine the anomalous phenomena in Deuterium/Solid System. A neutron detector containing 16 BF3 tubes with a detection limit of 0.38 n/s for two hour counting was used for electrolysis experiments. No neutron counting rate statistically higher than detection limit was observed from Fleischmann ampersand Pons type experiments. An HLNCC neutron detector equipped with 18 3He tubes and a JSR-11 shift register unit with a detection limit of 0.20 n/s for a two hour run was employed to study the neutron signals in D2 gas experiments. Different material pretreatments were selected to review the changes in frequency and size of the neutron burst production. Experiment sequence was deliberately designed to distinguish the neutron burst from fake signals, e.g. electronic noise pickup, the cosmic rays and other sources of environmental background. Ten batches of dry fusion samples were tested, among them, seven batches with neutron burst signals occurred roughly at the temperature from -100 degree centigrade to near room temperature. In the first four runs of a typical sample batch, seven neutron bursts were observed with neutron numbers from 15 to 482, which are 3 and 75 times, respectively, higher than the uncertainty of background. However, no bursts happened for H2 dummy samples running in-between and afterwards and for sample batch after certain runs

  16. Deuterium post-metallization anneal of electrochemical-plated Cu film deposited on different barrier materials

    International Nuclear Information System (INIS)

    In this paper, we report on electrochemical-plated (ECP) copper (Cu) film characterizations with different (Ta, TaN and TiN) barrier materials subjected to post-metallization-annealing (PMA) in deuterium (D2) under various annealing conditions. For comparison, post-metallization-anneal of the ECP Cu film in pure nitrogen (N2) and forming gas (20% hydrogen+80% nitrogen) were also performed. We used four-point probe to determine the sheet resistance. Scanning electron microscopy was used to examine the surface morphology of the after-annealed ECP Cu films. X-ray-diffraction (XRD) analysis was used to inspect the texture of the ECP Cu films before and after PMA. The deuterium distribution in the barrier layer was determined by using the secondary ion mass spectroscopy depth profile analysis. We found that under appropriate PMA conditions, the sheet resistance of ECP Cu films deposited on TaN barrier was the lowest after D2 PMA when compared with those deposited on TiN and Ta barriers

  17. Aperture Size Effect on Extracted Negative Ion Current Density

    Science.gov (United States)

    de Esch, H. P. L.; Svensson, L.; Riz, D.

    2009-03-01

    This paper discusses experimental results obtained at the 1 MV testbed at CEA Cadarache that appear to show a higher extracted D- current density from small apertures. Plasma grids with different shapes have been installed and tested. All grids had one single aperture. The tests were done in volume operation and in caesium operation. We tested four grids, two with O/14 mm, one with O/11 mm and one with O/8 mm apertures. No aperture size effect was observed in volume operation. In caesiated operation the extracted current density for the O/8 mm aperture appears to be significantly higher (˜50%) than for the O/14 mm aperture. Simulations with a 3D Monte Carlo Trajectory Following Code have shown an aperture size effect of about 20%. Finally, as byproducts of the experiments, data on backstreaming positive ions and the temperature of the plasma grid have been obtained.

  18. Fast-neutron, coded-aperture imager

    Energy Technology Data Exchange (ETDEWEB)

    Woolf, Richard S., E-mail: richard.woolf@nrl.navy.mil; Phlips, Bernard F., E-mail: bernard.phlips@nrl.navy.mil; Hutcheson, Anthony L., E-mail: anthony.hutcheson@nrl.navy.mil; Wulf, Eric A., E-mail: eric.wulf@nrl.navy.mil

    2015-06-01

    This work discusses a large-scale, coded-aperture imager for fast neutrons, building off a proof-of concept instrument developed at the U.S. Naval Research Laboratory (NRL). The Space Science Division at the NRL has a heritage of developing large-scale, mobile systems, using coded-aperture imaging, for long-range γ-ray detection and localization. The fast-neutron, coded-aperture imaging instrument, designed for a mobile unit (20 ft. ISO container), consists of a 32-element array of 15 cm×15 cm×15 cm liquid scintillation detectors (EJ-309) mounted behind a 12×12 pseudorandom coded aperture. The elements of the aperture are composed of 15 cm×15 cm×10 cm blocks of high-density polyethylene (HDPE). The arrangement of the aperture elements produces a shadow pattern on the detector array behind the mask. By measuring of the number of neutron counts per masked and unmasked detector, and with knowledge of the mask pattern, a source image can be deconvolved to obtain a 2-d location. The number of neutrons per detector was obtained by processing the fast signal from each PMT in flash digitizing electronics. Digital pulse shape discrimination (PSD) was performed to filter out the fast-neutron signal from the γ background. The prototype instrument was tested at an indoor facility at the NRL with a 1.8-μCi and 13-μCi 252Cf neutron/γ source at three standoff distances of 9, 15 and 26 m (maximum allowed in the facility) over a 15-min integration time. The imaging and detection capabilities of the instrument were tested by moving the source in half- and one-pixel increments across the image plane. We show a representative sample of the results obtained at one-pixel increments for a standoff distance of 9 m. The 1.8-μCi source was not detected at the 26-m standoff. In order to increase the sensitivity of the instrument, we reduced the fastneutron background by shielding the top, sides and back of the detector array with 10-cm-thick HDPE. This shielding configuration led

  19. Two-Dimensional Synthetic-Aperture Radiometer

    Science.gov (United States)

    LeVine, David M.

    2010-01-01

    A two-dimensional synthetic-aperture radiometer, now undergoing development, serves as a test bed for demonstrating the potential of aperture synthesis for remote sensing of the Earth, particularly for measuring spatial distributions of soil moisture and ocean-surface salinity. The goal is to use the technology for remote sensing aboard a spacecraft in orbit, but the basic principles of design and operation are applicable to remote sensing from aboard an aircraft, and the prototype of the system under development is designed for operation aboard an aircraft. In aperture synthesis, one utilizes several small antennas in combination with a signal processing in order to obtain resolution that otherwise would require the use of an antenna with a larger aperture (and, hence, potentially more difficult to deploy in space). The principle upon which this system is based is similar to that of Earth-rotation aperture synthesis employed in radio astronomy. In this technology the coherent products (correlations) of signals from pairs of antennas are obtained at different antenna-pair spacings (baselines). The correlation for each baseline yields a sample point in a Fourier transform of the brightness-temperature map of the scene. An image of the scene itself is then reconstructed by inverting the sampled transform. The predecessor of the present two-dimensional synthetic-aperture radiometer is a one-dimensional one, named the Electrically Scanned Thinned Array Radiometer (ESTAR). Operating in the L band, the ESTAR employs aperture synthesis in the cross-track dimension only, while using a conventional antenna for resolution in the along-track dimension. The two-dimensional instrument also operates in the L band to be precise, at a frequency of 1.413 GHz in the frequency band restricted for passive use (no transmission) only. The L band was chosen because (1) the L band represents the long-wavelength end of the remote- sensing spectrum, where the problem of achieving adequate

  20. Deuterium contents in water of various tissues from different subtypes of C4 plants

    International Nuclear Information System (INIS)

    The work summarized here is concerned with the use of deuterium in evaluating the position of the NADP-malate enzyme subtype in the C4 plant maize (Zea mays). The results show a higher deuterium concentration in the biomass, resulting from the use in the Calvin cycle of intercostal water enriched in deuterium by evapotranspiration. 2 refs, 1 tab

  1. Determination of gluconeogenesis in man by the use of deuterium-NMR-spectroscopy

    CERN Document Server

    Rosian, E

    2000-01-01

    The aim of this dissertation is the quantification of the deuterium--distribution in human glucose by the use of the deuterium NMR spectroscopy of deuteriated water. The glucose production in human organism is composed of gluconeogenesis and glycolysis. The quantification of the part of gluconeogenesis on the total glucose production was determined by the use of deuterium NMR spectroscopy. (boteke)

  2. High-Energy Ion Emission from Cooled Deuterium Clusters in 20 TW Laser Fields

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Jie; HUANG Wen-Zhong; WANG Guang-Chang; ZHOU Wei-Min; ZHANG Shuang-Gen; WANG Xiang-Xian; ZHOU Kai-Nan; WANG Xiao-Dong; HUANG Xiao-Jun; NI Guo-Quan; GU Yu-Qiu; WANG Hong-Bin; ZHENG Zhi-Jian; GE Fang-Fang; WEN Xian-Lun; JIAO Chun-Ye; HE Ying-Ling; WEN Tian-Shu

    2005-01-01

    @@ High-energy ion emission from intense-ultrashort (30fs) laser-pulse-cooled deuterium-cluster (80K) interaction is measured. The deuterium ions have an average energy 20 keV, which greatly exceeds Zweiback's expectation [Phys. Rev. Lett. 84 (2000) 2634]. These fast deuterium ions can be used to drive fusion and have a broad prospect.

  3. Deuterium isotope effect on swelling process in aqueous polymer gels

    International Nuclear Information System (INIS)

    The deuterium isotope effects on the swelling process of typical aqueous polymer gels (poly(N-isopropylacrylamide) gel and polyacrylamide gel) have been investigated in this study. The swelling times of both the poly(N-isopropylacrylamide) gel and the polyacrylamide gel in heavy water are longer than those in water. The deuterium isotope effect in the swelling process of gels is mainly arising from the higher viscosity in heavy water than in water. The additional deuterium isotope effect on the diffusion coefficient related to the swelling process should be due to the larger microscopic friction arising from the stronger polymer-solvent interaction in heavier water than in water. We also discuss in this paper the deuterium isotope effects on the size of the aqueous gels in the equilibrium state. Interestingly, the size in the equilibrium state of poly(N-isopropylacrylamide) gel in heavy water is larger than that in water. In contrast to poly(N-isopropylacrylamide) gel, the size in the equilibrium state of polyacrylamide gel in heavy water is smaller than that in water. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Laser separation of hydrogen isotopes: Tritium-from-deuterium recovery

    International Nuclear Information System (INIS)

    Single-step enrichment factors exceeding 15,000 have been observed in the removal of tritium-from-deuterium by 12 μm laser multiple-photon dissociation of chloroform. The photochemistry and photophysics of this process is discussed along with prospects for implementation of this method in practical heavy water reactor detritiation. 7 refs., 7 figs., 1 tab

  5. Use of 60 ppm deuterium depleted water in companionship animals

    International Nuclear Information System (INIS)

    There are presented the results of studies on the effects of deuterium depleted water in companionship animals. Based on these results, a new product was realized, 'Aqua Forte' that is a deuterium depleted potable water (60 ppm deuterium) with beneficial effects in animal's health maintaining. Aqua forte has prophylactic properties (in preventing diseases related to immune system) and therapeutic properties, as adjuvant in various therapeutic programs. The mechanism of action takes place at the cellular metabolism level by replacing the constitutional and free water of 150 ppm deuterium, this resulting in the stimulation of the immune cellular system and also of resistance at the onset of some pathological states. The non-specific stimulation implies performing both the humoral mediated immune reactions and of those cellularly mediated. Aqua forte is recommended in: - the feeding of the young weaned animals, the action being of growth stimulation, and increasing of the resistance against some diseases specific to the age; - as an adjuvant in some chronic diseases (hepatitis, pancreatitis, dermatological diseases, osteoarthropaties, hepato-renal syndrome, renal insufficiency, after surgical interventions, in antitumoral therapy); - in the feeding of the old animals for the quality of life improvement. (authors)

  6. Contribution of Beam-Driven Fusion in Pure Deuterium Plasma

    International Nuclear Information System (INIS)

    The urgent and ultimate goal of the fusion research is to accomplish a fusion reactor functioning practically. Though the first fusion reactor is expected to use a DT fuel, most fusion researchers have studied H or D plasmas instead of DT plasma because of radioactivity and resource problems. DD plasma experiments, now a usual trend, can give useful information on the fusion plasma physics, tritium retention, alpha particle transport, neutronics, and so on at a safe controlled radiation level. The KSTAR tokamak, all-superconductor world level fusion research device, has been operated with pure deuterium plasmas since the 2010 campaign, however, the thermal fusion reaction rate is still far below significant because of low plasma temperature. The NBI system equipped on the KSTAR tokamak can deliver more than 1.5 MW input power of deuterium neutral beam at 100 keV with one ion source, which have contributed to making H-mode plasmas for several seconds. The next goal of the NBI input power at the 2012 campaign is 3.5 MW with two ion sources. Hot ions generated from the deuterium neutral beam injected into the D plasma can produce beam-driven fusion reactions at a much more notable level than thermal ones. Contribution of deuterium neutral beam injection on the fusion reactions in a D plasma is preliminarily assessed here

  7. Deuterium depletion induces anxiolytic-like effects in rats

    Directory of Open Access Journals (Sweden)

    Mladin Cristian

    2014-01-01

    Full Text Available Deuterium-depleted water (DDW has a concentration of deuterium 6-7 times lower than naturally occurring water (20-25 ppm vs. 150 ppm. When administered for a longer period, it can reduce the concentration of deuterium throughout the body, activating cellular mechanisms that depend on protons. The aim of the present work was to investigate the influence of chronic DDW administration on anxiety-related processes in Wistar rats when compared to a control group that received distilled water, as studied in an elevated plus maze behavioral test. Our results describe a possible anxiolytic-like effect of DDW administration on rats, as shown by the increase in the percentage of time and number of entries in the open arms of the elevated plus maze. The administration of DDW also resulted in stimulated head-dipping behavior in the open arms, which is a behavioral change that characterizes the exploratory behavior and decreased inhibition/ fear in an unfamiliar environment. We conclude that the change in this balance may have important consequences for many biological mechanisms. A deuterium desaturation treatment with DDW might have a use in anxiety disorders.

  8. 'Excess heat' induced by deuterium flux in palladium film

    International Nuclear Information System (INIS)

    An early work at NASA, USA has repeated at INFICON Balzers, Liechtenstein in 2005. It is a confirmation of the correlation between excess heat and deuterium flux permeating through the Pd film. The maximum excess power density is of the order of 100 W/cm3 (Pd). (author)

  9. High electric field deuterium ion sources for neutron generators

    Science.gov (United States)

    Reichenbach, Birk

    Active interrogation systems for highly enriched uranium require improved fieldable neutron sources. The target technology for deuterium-tritium neutron generators is well understood and the most significant improvement can be achieved by improving the deuterium ion source through increased output and, in some cases, lifetime of the ion source. We are developing a new approach to a deuterium ion sources based upon the field desorption/evaporation of deuterium from the surfaces of metal tips. Electrostatic field desorption (EFD) desorbs previously adsorbed deuterium as ions under the influence of high electric fields (several V/A), without removing tip material. Single etched wire tip experiments have been performed and have shown that this is difficult but can be achieved with molybdenum and tungsten tips. Electrostatic field evaporation (EFE) evaporates ultra thin deuterated titanium films as ions. It has been shown that several 10s of atomic layers can be removed within a few nanoseconds from etched tungsten tips. In the course of these studies titanium deposition and deuteration methods were studied and new detection methods developed. Space charge effects resulting from the large ion currents were identified to be the most likely cause of some unusual ion emission characteristics. In addition, on W oriented substrates a surprising body-centered cubic crystal structure of the titanium film was found and studied. The ion currents required for neutron generator applications can be achieved by microfabrication of metal tip arrays. Field desorption studies of microfabricated field emitter tip arrays have been conducted for the first time. Maximum fields of 3 V/A have been applied to the array tip surfaces to date, although fields of ˜ 2 V/A to ˜ 2.5 V/A are more typical. Desorption of atomic deuterium ions has been observed at fields of roughly 2 V/A at room temperature. The desorption of common surface adsorbates, such as hydrogen, carbon, water, and carbon

  10. Deuterium Burning in Massive Giant Planets and Low-Mass Brown Dwarfs formed by Core-Nucleated Accretion

    CERN Document Server

    Bodenheimer, Peter; Lissauer, Jack J; Fortney, Jonathan J; Saumon, Didier

    2013-01-01

    Formation of bodies near the deuterium-burning limit is considered by detailed numerical simulations according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 Mearth, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (Mjup). After the formation process, which lasts 1-5 Myr and which ends with a 'cold-start', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M50, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M50 fall in the range 11.6-13.6 Mjup, in agreement with previous determinations that do not take the formati...

  11. Development of Approaches for Deuterium Incorporation in Plants

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [ORNL

    2015-01-01

    Soon after the discovery of deuterium, efforts to utilize this stable isotope of hydrogen for labeling of plants began and have proven successful for natural abundance to 20% enrichment. However, isotopic labeling with deuterium (2H) in higher plants at the level of 40% and higher is complicated by both physiological responses, particularly water exchange through transpiration, and inhibitory effects of D2O on germination, rooting, and growth. The highest incorporation of 40 50% had been reported for photoheterotrophic cultivation of the duckweed Lemna. Higher substitution is desirable for certain applications using neutron scattering and nuclear magnetic resonance (NMR) techniques. 1H2H-NMR and mass spectroscopy are standard methods frequently used for determination of location and amount of deuterium substitution. The changes in infrared (IR) absorption observed for H to D substitution in hydroxyl and alkyl groups provide rapid initial evaluation of incorporation. Short-term experiments with cold-tolerant annual grasses can be carried out in enclosed growth containers to evaluate incorporation. Growth in individual chambers under continuous air perfusion with dried sterile-filtered air enables long-term cultivation of multiple plants at different D2O concentrations. Vegetative propagation from cuttings extends capabilities to species with low germination rates. Cultivation in 50% D2O of annual ryegrass and switchgrass following establishment of roots by growth in H2O produces samples with normal morphology and 30 40 % deuterium incorporation in the biomass. Winter grain rye (Secale cereale) was found to efficiently incorporate deuterium by photosynthetic fixation from 50% D2O but did not incorporate deuterated phenylalanine-d8 from the growth medium.

  12. A new pad-based neutron detector for stereo coded aperture thermal neutron imaging

    Science.gov (United States)

    Dioszegi, I.; Yu, B.; Smith, G.; Schaknowski, N.; Fried, J.; Vanier, P. E.; Salwen, C.; Forman, L.

    2014-09-01

    A new coded aperture thermal neutron imager system has been developed at Brookhaven National Laboratory. The cameras use a new type of position-sensitive 3He-filled ionization chamber, in which an anode plane is composed of an array of pads with independent acquisition channels. The charge is collected on each of the individual 5x5 mm2 anode pads, (48x48 in total, corresponding to 24x24 cm2 sensitive area) and read out by application specific integrated circuits (ASICs). The new design has several advantages for coded-aperture imaging applications in the field, compared to the previous generation of wire-grid based neutron detectors. Among these are its rugged design, lighter weight and use of non-flammable stopping gas. The pad-based readout occurs in parallel circuits, making it capable of high count rates, and also suitable to perform data analysis and imaging on an event-by-event basis. The spatial resolution of the detector can be better than the pixel size by using a charge sharing algorithm. In this paper we will report on the development and performance of the new pad-based neutron camera, describe a charge sharing algorithm to achieve sub-pixel spatial resolution and present the first stereoscopic coded aperture images of thermalized neutron sources using the new coded aperture thermal neutron imager system.

  13. Urea and deuterium mixtures at high pressures

    International Nuclear Information System (INIS)

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D2 mixtures that indicate no inclusion compound forms up to 3.7 GPa

  14. Optimization of synthetic aperture image quality

    Science.gov (United States)

    Moshavegh, Ramin; Jensen, Jonas; Villagomez-Hoyos, Carlos A.; Stuart, Matthias B.; Hemmsen, Martin Christian; Jensen, Jørgen Arendt

    2016-04-01

    Synthetic Aperture (SA) imaging produces high-quality images and velocity estimates of both slow and fast flow at high frame rates. However, grating lobe artifacts can appear both in transmission and reception. These affect the image quality and the frame rate. Therefore optimization of parameters effecting the image quality of SA is of great importance, and this paper proposes an advanced procedure for optimizing the parameters essential for acquiring an optimal image quality, while generating high resolution SA images. Optimization of the image quality is mainly performed based on measures such as F-number, number of emissions and the aperture size. They are considered to be the most contributing acquisition factors in the quality of the high resolution images in SA. Therefore, the performance of image quality is quantified in terms of full-width at half maximum (FWHM) and the cystic resolution (CTR). The results of the study showed that SA imaging with only 32 emissions and maximum sweep angle of 22 degrees yields a very good image quality compared with using 256 emissions and the full aperture size. Therefore the number of emissions and the maximum sweep angle in the SA can be optimized to reach a reasonably good performance, and to increase the frame rate by lowering the required number of emissions. All the measurements are performed using the experimental SARUS scanner connected to a λ/2-pitch transducer. A wire phantom and a tissue mimicking phantom containing anechoic cysts are scanned using the optimized parameters for the transducer. Measurements coincide with simulations.

  15. Blister bursting and deuterium bursting release from tungsten exposed to high fluences of high flux and low energy deuterium plasma

    International Nuclear Information System (INIS)

    Deuterium retention and blistering in the near-surface region of tungsten exposed to high fluences (up to 1027 D m-2) of high flux (1022D+ m-2 s-1) and low energy (38 eV) deuterium plasma were examined with scanning electron microscopy, focused ion beam and thermal desorption spectroscopy (TDS). Two kinds of blisters appeared at the recrystallized tungsten exposed to the plasma at 520 K. One is the large blisters with sizes of a few tens of micrometres and varying ratios of height against width (up to 0.6), and the other is the small blisters with sizes of less than a few micrometres and a large ratio of height against diameter (about 0.7). A peculiar phenomenon of blister bursting with a tail, or partially opened or fully opened lid was found on some grains after plasma exposure or TDS experiment. In addition, bursting release of deuterium with sudden peaks was observed in the TDS curve below 700 K at a heating rate of 0.5 K s-1. A new model named 'step-cascade model' was proposed to explain the blister bursting. Furthermore, the origin of deuterium retention and blistering as well as future work on high-Z materials were discussed

  16. DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

    Energy Technology Data Exchange (ETDEWEB)

    Bodenheimer, Peter [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); D' Angelo, Gennaro; Lissauer, Jack J. [Space Science and Astrobiology Division, NASA-Ames Research Center, Moffett Field, CA 94035 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Saumon, Didier, E-mail: peter@ucolick.org, E-mail: gennaro.dangelo@nasa.gov, E-mail: Jack.J.Lissauer@nasa.gov, E-mail: jfortney@ucolick.org, E-mail: dsaumon@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

    2013-06-20

    Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M{sub Circled-Plus }, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (M{sub Jup}). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M{sub 50}, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M{sub 50} fall in the range 11.6-13.6 M{sub Jup}, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M{sub 50}. For masses above M{sub 50}, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.

  17. DEUTERIUM BURNING IN MASSIVE GIANT PLANETS AND LOW-MASS BROWN DWARFS FORMED BY CORE-NUCLEATED ACCRETION

    International Nuclear Information System (INIS)

    Using detailed numerical simulations, we study the formation of bodies near the deuterium-burning limit according to the core-nucleated giant planet accretion scenario. The objects, with heavy-element cores in the range 5-30 M⊕, are assumed to accrete gas up to final masses of 10-15 Jupiter masses (MJup). After the formation process, which lasts 1-5 Myr and which ends with a ''cold-start'', low-entropy configuration, the bodies evolve at constant mass up to an age of several Gyr. Deuterium burning via proton capture is included in the calculation, and we determined the mass, M50, above which more than 50% of the initial deuterium is burned. This often-quoted borderline between giant planets and brown dwarfs is found to depend only slightly on parameters, such as core mass, stellar mass, formation location, solid surface density in the protoplanetary disk, disk viscosity, and dust opacity. The values for M50 fall in the range 11.6-13.6 MJup, in agreement with previous determinations that do not take the formation process into account. For a given opacity law during the formation process, objects with higher core masses form more quickly. The result is higher entropy in the envelope at the completion of accretion, yielding lower values of M50. For masses above M50, during the deuterium-burning phase, objects expand and increase in luminosity by one to three orders of magnitude. Evolutionary tracks in the luminosity versus time diagram are compared with the observed position of the companion to Beta Pictoris.

  18. Multibeam synthetic aperture radar for global oceanography

    Science.gov (United States)

    Jain, A.

    1979-01-01

    A single-frequency multibeam synthetic aperture radar concept for large swath imaging desired for global oceanography is evaluated. Each beam iilluminates a separate range and azimuth interval, and images for different beams may be separated on the basis of the Doppler spectrum of the beams or their spatial azimuth separation in the image plane of the radar processor. The azimuth resolution of the radar system is selected so that the Doppler spectrum of each beam does not interfere with the Doppler foldover due to the finite pulse repetition frequency of the radar system.

  19. Tissue Harmonic Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Rasmussen, Joachim; Jensen, Jørgen Arendt

    2014-01-01

    Synthetic aperture sequential beamforming (SASB) and tissue har- monic imaging (THI) are combined to improve the image quality of medical ultrasound imaging. The technique is evaluated in a compar- ative study against dynamic receive focusing (DRF). The objective is to investigate if SASB combined...... with THI improves the image qual- ity compared to DRF-THI. The major benet of SASB is a reduced bandwidth between the probe and processing unit. A BK Medical 2202 Ultraview ultrasound scanner was used to acquire beamformed RF data for oine evaluation. The acquisition was made interleaved between...

  20. Cancellation of singularities for synthetic aperture radar

    Science.gov (United States)

    Caday, Peter

    2015-01-01

    In a basic model for synthetic aperture radar (SAR) imaging, one wishes to recover a function or distribution f from line integrals over circles whose centers lie on a given curve γ. In this paper, we consider the problem of recovering the singularities (wavefront set) of f given its SAR data, and specifically whether it is possible to choose a singular f whose singularities are hidden from γ, meaning that its SAR data is smooth. We show that f 's singularities can be hidden to leading order if a certain discrete reflection map is the identity, and give examples where this is the case. Finally, numerical experiments illustrate the hiding of singularities.

  1. Development of large aperture composite adaptive optics

    Czech Academy of Sciences Publication Activity Database

    Kmetík, Viliam; Vítovec, Bohumil; Jiran, L.; Němcová, Š.; Zicha, J.; Inneman, A.; Mikuličková, L.; Pavlica, R.

    Vol. 9442. Bellingham: SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Kovačičinová, J.; Vít, T.), 94420L-94420L. (SPIE). ISBN 978-1-62841-557-5. ISSN 0277-786X. [Optics and Measurement Conference 2014 (OaM 2014). Liberec (CZ), 07.10.2014-10.10.2014] R&D Projects: GA TA ČR TA01010878 Institutional support: RVO:61389021 Keywords : Large aperture * adaptive optics * deformable mirror * bimorph deformable mirror * composite optics Subject RIV: BH - Optics, Masers, Lasers http://dx.doi.org/10.1117/12.2175713 .

  2. Digital exploitation of synthetic aperture radar

    Science.gov (United States)

    Wagner, H. L.; Shuchman, R. A.

    1977-01-01

    A digital processing and analysis scheme for use with digitized synthetic aperture radar data was developed. Using data from a four channel system, the imagery is preprocessed using specially designed software and then analyzed using preexisting facilities originally intended for use with MSS type data. Geometric and radiometric correction may be performed if desired, as well as classification analysis, Fast Fourier transform, filtering and level slice and display functions. The system provides low cost output in real time, permitting interactive imagery analysis. System information flow diagrams as well as sample output products are shown.

  3. Cancellation of singularities for synthetic aperture radar

    International Nuclear Information System (INIS)

    In a basic model for synthetic aperture radar (SAR) imaging, one wishes to recover a function or distribution f from line integrals over circles whose centers lie on a given curve γ. In this paper, we consider the problem of recovering the singularities (wavefront set) of f given its SAR data, and specifically whether it is possible to choose a singular f whose singularities are hidden from γ, meaning that its SAR data is smooth. We show that f 's singularities can be hidden to leading order if a certain discrete reflection map is the identity, and give examples where this is the case. Finally, numerical experiments illustrate the hiding of singularities. (paper)

  4. The deuterium/hydrogen distribution in chondritic organic matter attests to early ionizing irradiation.

    Science.gov (United States)

    Laurent, Boris; Roskosz, Mathieu; Remusat, Laurent; Robert, François; Leroux, Hugues; Vezin, Hervé; Depecker, Christophe; Nuns, Nicolas; Lefebvre, Jean-Marc

    2015-01-01

    Primitive carbonaceous chondrites contain a large array of organic compounds dominated by insoluble organic matter (IOM). A striking feature of this IOM is the systematic enrichment in deuterium compared with the solar hydrogen reservoir. This enrichment has been taken as a sign of low-temperature ion-molecule or gas-grain reactions. However, the extent to which Solar System processes, especially ionizing radiation, can affect D/H ratios is largely unknown. Here, we report the effects of electron irradiation on the hydrogen isotopic composition of organic precursors containing different functional groups. From an initial terrestrial composition, overall D-enrichments and differential intramolecular fractionations comparable with those measured in the Orgueil meteorite were induced. Therefore, ionizing radiation can quantitatively explain the deuteration of organics in some carbonaceous chondrites. For these meteorites, the precursors of the IOM may have had the same isotopic composition as the main water reservoirs of the inner Solar System. PMID:26461170

  5. Time-resolved pulsed hydrogen/deuterium exchange mass spectrometry probes gaseous proteins structural kinetics.

    Science.gov (United States)

    Rajabi, Khadijeh

    2015-01-01

    A pulsed hydrogen/deuterium exchange (HDX) method has been developed for rapid monitoring of the exchange kinetics of protein ions with D2O a few milliseconds after electrospray ionization (ESI). The stepwise gradual evolution of HDX of multiply charged protein ions was monitored using the pulsed HDX mass spectrometry technique. Upon introducing a very short pulse of D2O (in the μs to ms time scale) into the linear ion trap (LIT) of a time-of-flight (TOF) mass spectrometer, bimodal distributions were detected for the ions of cytochrome c and ubiquitin. Mechanistic details of HDX reactions for ubiquitin and cytochrome c in the gas phase were uncovered and the structural transitions were followed by analyzing the kinetics of HDX. PMID:25318698

  6. Role of charge exchange neutrals in the deuterium retention for Tore Supra long discharges

    International Nuclear Information System (INIS)

    In Tore Supra long pulses, particle balance gives evidence that a constant fraction of the injected gas is retained in the wall all along the shot (typically 50%), showing no sign of wall saturation after more than 6 minutes of discharge. During the discharge, the retention rate first decreases (phase 1), then remains constant throughout the pulse (phase 2). Phase 1 could be interpreted as implantation of particles combined with a constant co-deposition rate, while phase 2 could correspond to co-deposition alone, once the implanted surfaces are saturated with deuterium. This paper presents a possible contribution of charge exchange neutrals to the implantation process, based on modelling results with the Eirene neutral transport code. A complex pattern of particle implantation is evidenced, with saturation time constants ranging from less than one to several hundreds seconds, compatible with the experimental behaviour during phase 1. (authors)

  7. Evidence for stratification of deuterium-tritium fuel in inertial confinement fusion implosions.

    Science.gov (United States)

    Casey, D T; Frenje, J A; Johnson, M Gatu; Manuel, M J-E; Rinderknecht, H G; Sinenian, N; Séguin, F H; Li, C K; Petrasso, R D; Radha, P B; Delettrez, J A; Glebov, V Yu; Meyerhofer, D D; Sangster, T C; McNabb, D P; Amendt, P A; Boyd, R N; Rygg, J R; Herrmann, H W; Kim, Y H; Bacher, A D

    2012-02-17

    Measurements of the D(d,p)T (dd) and T(t,2n)(4)He (tt) reaction yields have been compared with those of the D(t,n)(4)He (dt) reaction yield, using deuterium-tritium gas-filled inertial confinement fusion capsule implosions. In these experiments, carried out on the OMEGA laser, absolute spectral measurements of dd protons and tt neutrons were obtained. From these measurements, it was concluded that the dd yield is anomalously low and the tt yield is anomalously high relative to the dt yield, an observation that we conjecture to be caused by a stratification of the fuel in the implosion core. This effect may be present in ignition experiments planned on the National Ignition Facility. PMID:22401216

  8. The enrichment of tritium in hydrogen or deuterium by thermal diffusion

    International Nuclear Information System (INIS)

    Tritium in H2, 1.7 x 10-2 Cimol-1, was enriched by means of therma l diffusion at the bottom of a 100-cm glass column with a gas reservoir on top. Four columns with different diameters (8, 20, 30, and 41 mmdiameter) were used. The temperature of the wire stretched along the axis of the column was changed over a range from 2000C to 4500C. The maximum equilibrium separation factors in hydrogen and in deuterium were 17 and 4.5 respectively. The optimum diameters were estimated by a modification of Waldmann's equation, which can be used for the separation using the flat-type system. (author)

  9. Formation of β-PdD containing high deuterium concentration using electrolysis of heavy-water

    International Nuclear Information System (INIS)

    The limiting composition of β-PdD obtained during electrolytic loading results from a complex competition between diffusion of D atoms through any surface barrier, diffusion within the bulk sample, and loss of deuterium gas from surface-penetrating cracks. Reductions in surface-crack concentration and surface-barriers are essential steps to achieve high compositions. The highest compositions within any sample are located within the surface region as a complex patch-work of values. The open circuit voltage (OCV), referenced to platinum, is useful in understanding changes in the surface composition and structure. Values as high as -1.35 V have been observed for highly loaded β-PdD. Evidence for several new, possibly impurity stabilized structures is given. (orig.)

  10. Beta-layering of solid deuterium-tritium in a spherical polycarbonate shell

    International Nuclear Information System (INIS)

    In this paper, the authors examine two of the variables that affect the beta-layering process in which nonuniform layers of solid deuterium-tritium (DT) are driven toward uniformity by beta-decay induced sublimation. For these experiments, a 9 mm diameter polycarbonate sphere was partially filled with a 50-50 mix of DT liquid, frozen, and then held at 17 K. The authors measured the equilibration time constant r as functions of solid layer thickness, He exchange gas pressure, and age. Solid layer thicknesses ranged from 200 μm to 650 μ, exchange gas pressures from 0 to 600 torr, and age from 0 to 104 days. Results show a significant final solid layer anisotropy with exchange gas pressures above 5 torr, and r values that increased with age by 0.01 min/day for 200 μm-thick layers, and by 0.5 min/day for 650 μm-thick layers. The time constant is shown to be a weak function of exchange gas pressure

  11. Deuterium abundances along three extended sightlines from FUSE observations: Preliminary Results

    Science.gov (United States)

    Oliveira, C. M.; Moos, H. W.; Hebrard, G.; Knauth, D. C.

    2005-12-01

    Observations of the deuterium abundance, D/H, in the interstellar medium provide important constraints on Galactic chemical evolution models as well as on the Big Bang nucleosynthesis theory. Recent results from FUSE have shown that for sightlines with log N(H) > 20.7, D/H is approximately half of that in the Local Bubble (D/HLB 1.6E-5), with large variations for sightlines with N(H) larger than the Local Bubble but smaller than 20.7. These results, in conjunction with results obtained with other observatories such as Copernicus and IMAPS, have questioned the previously held assumption that D/HLB is representative of the present-epoch abundance of deuterium. The causes of the low D/H at high N(H) as well as of the variations in the intermediate N(H) range are currently unknown. Depletion onto dust grains, infall of metal-poor gas and variable astration are mechanisms being considered to explain the D/H variations. However, the small number of sightlines with log N(H)> 20.7 for which D/H has been measured limits progress in this area. In this work we use new FUSE data to derive column densities of DI, NI, OI, FeII and other species along three sightlines with log N(H) > 20.9, probing gas over distances larger than 1 Kpc. In conjunction with N(HI) derived from IUE data we compute D/H, N/H, O/H, and Fe/H ratios which are then compared to values in the literature. This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by The Johns Hopkins University. Financial support to U. S. participants has been provided in part by NASA contract NAS5-32985 to Johns Hopkins University.

  12. Heat generation above break-even from laser-induced fusion in ultra-dense deuterium

    International Nuclear Information System (INIS)

    Previous results from laser-induced processes in ultra-dense deuterium D(0) give conclusive evidence for ejection of neutral massive particles with energy >10 MeV u−1. Such particles can only be formed from nuclear processes like nuclear fusion at the low laser intensity used. Heat generation is of interest for future fusion energy applications and has now been measured by a small copper (Cu) cylinder surrounding the laser target. The temperature rise of the Cu cylinder is measured with an NTC resistor during around 5000 laser shots per measured point. No heating in the apparatus or the gas feed is normally used. The fusion process is suboptimal relative to previously published studies by a factor of around 10. The small neutral particles HN(0) of ultra-dense hydrogen (size of a few pm) escape with a substantial fraction of the energy. Heat loss to the D2 gas (at <1 mbar pressure) is measured and compensated for under various conditions. Heat release of a few W is observed, at up to 50% higher energy than the total laser input thus a gain of 1.5. This is uniquely high for the use of deuterium as fusion fuel. With a slightly different setup, a thermal gain of 2 is reached, thus clearly above break-even for all neutronicity values possible. Also including the large kinetic energy which is directly measured for MeV particles leaving through a small opening gives a gain of 2.3. Taking into account the lower efficiency now due to the suboptimal fusion process, previous studies indicate a gain of at least 20 during long periods

  13. Heat generation above break-even from laser-induced fusion in ultra-dense deuterium

    Directory of Open Access Journals (Sweden)

    Leif Holmlid

    2015-08-01

    Full Text Available Previous results from laser-induced processes in ultra-dense deuterium D(0 give conclusive evidence for ejection of neutral massive particles with energy >10 MeV u−1. Such particles can only be formed from nuclear processes like nuclear fusion at the low laser intensity used. Heat generation is of interest for future fusion energy applications and has now been measured by a small copper (Cu cylinder surrounding the laser target. The temperature rise of the Cu cylinder is measured with an NTC resistor during around 5000 laser shots per measured point. No heating in the apparatus or the gas feed is normally used. The fusion process is suboptimal relative to previously published studies by a factor of around 10. The small neutral particles HN(0 of ultra-dense hydrogen (size of a few pm escape with a substantial fraction of the energy. Heat loss to the D2 gas (at <1 mbar pressure is measured and compensated for under various conditions. Heat release of a few W is observed, at up to 50% higher energy than the total laser input thus a gain of 1.5. This is uniquely high for the use of deuterium as fusion fuel. With a slightly different setup, a thermal gain of 2 is reached, thus clearly above break-even for all neutronicity values possible. Also including the large kinetic energy which is directly measured for MeV particles leaving through a small opening gives a gain of 2.3. Taking into account the lower efficiency now due to the suboptimal fusion process, previous studies indicate a gain of at least 20 during long periods.

  14. Coded aperture optimization using Monte Carlo simulations

    International Nuclear Information System (INIS)

    Coded apertures using Uniformly Redundant Arrays (URA) have been unsuccessfully evaluated for two-dimensional and three-dimensional imaging in Nuclear Medicine. The images reconstructed from coded projections contain artifacts and suffer from poor spatial resolution in the longitudinal direction. We introduce a Maximum-Likelihood Expectation-Maximization (MLEM) algorithm for three-dimensional coded aperture imaging which uses a projection matrix calculated by Monte Carlo simulations. The aim of the algorithm is to reduce artifacts and improve the three-dimensional spatial resolution in the reconstructed images. Firstly, we present the validation of GATE (Geant4 Application for Emission Tomography) for Monte Carlo simulations of a coded mask installed on a clinical gamma camera. The coded mask modelling was validated by comparison between experimental and simulated data in terms of energy spectra, sensitivity and spatial resolution. In the second part of the study, we use the validated model to calculate the projection matrix with Monte Carlo simulations. A three-dimensional thyroid phantom study was performed to compare the performance of the three-dimensional MLEM reconstruction with conventional correlation method. The results indicate that the artifacts are reduced and three-dimensional spatial resolution is improved with the Monte Carlo-based MLEM reconstruction.

  15. Aperture determination by long term and multiparticle tracking

    International Nuclear Information System (INIS)

    Apertures determined by long term tracking for 106 turns at β* = 2m and 6m and tracking of 100 particles for 1,000 turns at β* = 2m are reported. The multiparticle results are consistent with the aperture determined from 106 turn runs. Finally, the 106 turn results are extrapolated to 3 x 109 turns to obtain an estimate of the aperture for which particles survive for 10 hours in RHIC

  16. Magnetically tunable broadband transmission through a single small aperture

    OpenAIRE

    Ke Bi; Wenjun Liu; Yunsheng Guo; Guoyan Dong; Ming Lei

    2015-01-01

    Extraordinary transmission through a small aperture is of great interest. However, it faces a limitation that most of approaches can not realize the tunable transmission property, which is not benefit for the miniaturization of the microwave system. Here, we demonstrate a magnetically tunable broadband transmission through a small aperture. By placing two ferrite rods symmetrically on both sides of a single small aperture, the strongly localized electromagnetic fields are effectively coupled ...

  17. An Introduction of Aperture Coupled Microstrip Slot Antenna

    OpenAIRE

    Zarreen Aijaz; S.C Shrivastava

    2010-01-01

    A microstrip slot antenna is very small and lightweight still it has the problem of back radiation due to which power loss occurs and the SAR increases. To reduce the back lobe a technique introduces i.e. aperture coupled microstrip slot antenna which reduces the back lobe as well as increases the bandwidth of the antenna. Aperture coupled microstrip slot antenna couples the patch antenna with microstripline through an aperture.

  18. Optical Phase Imaging Using Synthetic Aperture Illumination and Phase Retrieval

    CERN Document Server

    Lee, Dennis J

    2016-01-01

    We perform quantitative phase imaging using phase retrieval to implement synthetic aperture imaging. Compared to digital holography, the developed technique is simpler, less expensive, and more stable.

  19. Jacobi-Bessel analysis of reflector antennas with elliptical apertures

    Science.gov (United States)

    Rahmat-Samii, Yahya

    1987-01-01

    Although many reflector antennas possess circular projected apertures, there are recent satellite and ground antenna applications for which it is desirable to employ reflectors with elliptical apertures. Here a modification of the Jacobi-Bessel expansion is presented for the diffraction analysis of reflectors with elliptical apertures. A comparative study is also performed between this modified Jacobi-Bessel algorithm and the one which uses the Jacobi-Bessel expansion over a circumscribing circular region. Numerical results are presented for offset reflectors with elliptical and circular apertures and the improved convergence properties of the modified algorithm are highlighted.

  20. Theory of the n=2 levels in muonic deuterium

    CERN Document Server

    Krauth, Julian J; Franke, Beatrice; Antognini, Aldo; Kottmann, Franz; Pohl, Randolf

    2015-01-01

    The present knowledge of Lamb shift, fine- and hyperfine structure of the $\\mathrm{2S}$ and $\\mathrm{2P}$ states in muonic deuterium is reviewed in anticipation of the results of a first measurement of several $\\mathrm{2S-2P}$ transition frequencies in muonic deuterium ({\\mu}d). A term-by-term comparison of all available sources reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift, which are essential for a determination of the deuteron rms charge radius from {\\mu}d. Apparent discrepancies between different sources are resolved, in particular for the difficult two-photon exchange contributions. Problematic single-sourced terms are identified which require independent recalculation.

  1. Biological Influence of Deuterium on Procariotic and Eukaryotic Cells

    Directory of Open Access Journals (Sweden)

    Oleg Mosin

    2014-03-01

    Full Text Available Biologic influence of deuterium (D on cells of various taxonomic groups of prokaryotic and eukaryotic microorganisms realizing methylotrophic, chemoheterotrophic, photo-organotrophic, and photosynthetic ways of assimilation of carbon substrates are investigated at growth on media with heavy water (D2О. The method of step by step adaptation technique of cells to D2О was developed, consisting in plating of cells on 2 % agarose nutrient media containing increasing gradient of concentration of D2О (from 0 up to 98 % D2O and the subsequent selection of stable to D2O cells. In the result of that technique were obtained adapted to maximum concentration of D2O cells, biological material of which instead of hydrogen contained deuterium with levels of enrichment 92–97,5 at.% D.

  2. Inelastic x-ray scattering from shocked liquid deuterium.

    Science.gov (United States)

    Regan, S P; Falk, K; Gregori, G; Radha, P B; Hu, S X; Boehly, T R; Crowley, B J B; Glenzer, S H; Landen, O L; Gericke, D O; Döppner, T; Meyerhofer, D D; Murphy, C D; Sangster, T C; Vorberger, J

    2012-12-28

    The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation-driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Ly(α) line emission at 2.96 keV. These first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5  eV, an electron density of 2.2(±0.5)×10(23)  cm(-3), and an ionization of 0.8 (-0.25, +0.15). Two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results. PMID:23368573

  3. Deuteride phase formation during implantation of deuterium into Ti

    International Nuclear Information System (INIS)

    The structure and kinetics of deuteride phase formation in samples of deuterium implanted into Ti for different doses were studied using secondary ion mass spectrometry and glancing incidence x-ray diffraction technique. It was observed that the deuterium after implantation at room temperature migrates towards the surface, from the implanted layer, until a saturation concentration is reached in the near surface region at a fluence of about 5 x 1017 D+ ions/cm2. On further implantation this layer grows inward producing rectangular type profiles. The maximum composition of this layer is around [D]/[Ti] (∼) 1. Glancing incidence XRD showed the presence of titanium deuteride phase having body centered tetragonal structure. The paper discusses the possible factors contributing to the deuteride phase formation at the surface. (author). 10 refs., 3 figs

  4. Kinetic Deuterium Isotope Effects in Cytochrome P450 Oxidation Reactions

    Science.gov (United States)

    Guengerich, F. Peter

    2016-01-01

    Cytochrome P450 (P450) enzymes account for ~ 75% of the metabolism of drugs. Most of the reactions catalyzed by P450s are mixed-function oxidations, and a C-H bond is (usually) broken. The rate-limiting nature of this step can be analyzed using the kinetic isotope effect (KIE) approach. The most relevant type of KIE is one termed intermolecular non-competitive, indicative of rate-limiting C-H bond breaking. A KIE vs. kcat for several P450s showed a correlation coefficient (r2) of 0.62. Deuterium substitution has been considered as a potential means of slowing drug metabolism or redirecting sites of metabolism in some cases, and several general points can be made regarding the potential for application of deuterium in drug design/development based on what is known about P450 KIEs. PMID:24285515

  5. Ion irradiated graphite exposed to fusion-relevant deuterium plasma

    International Nuclear Information System (INIS)

    Graphite samples were irradiated with 5 MeV carbon ions to simulate the damage caused by collision cascades from neutron irradiation in a fusion environment. The ion irradiated graphite samples were then exposed to a deuterium plasma in the linear plasma device, MAGPIE, for a total ion fluence of ∼1 × 1024 ions m−2. Raman and near edge X-ray absorption fine structure (NEXAFS) spectroscopy were used to characterize modifications to the graphitic structure. Ion irradiation was observed to decrease the graphitic content and induce disorder in the graphite. Subsequent plasma exposure decreased the graphitic content further. Structural and surface chemistry changes were observed to be greatest for the sample irradiated with the greatest fluence of MeV ions. D retention was measured using elastic recoil detection analysis and showed that ion irradiation increased the amount of retained deuterium in graphite by a factor of four

  6. Carbon deposition and deuterium inventory in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Carbon erosion and deposition in the ASDEX Upgrade divertor was investigated using a poloidal section of marked divertor tiles and silicon samples below the divertor structure. The whole inner divertor is a net carbon deposition area, while a large fraction of the outer divertor is erosion dominated and the roof baffle tiles show a complicated distribution of erosion and deposition areas. In total, 43.7 g B+C were redeposited, of which 88% were deposited on tiles and 9% in remote areas (below roof baffle, on vessel wall structures). Identified carbon sources in the main chamber are too low by a factor of ten to explain the observed carbon divertor deposition, but carbon erosion is observed at the outer divertor tiles. Deuterium is trapped mainly on the surfaces of the inner divertor tiles. The long term retention in codeposited hydrocarbon layers is about 3% of the total deuterium fuel input. (author)

  7. Deuterium-depleted water. Short history and news

    International Nuclear Information System (INIS)

    Deuterium-depleted water represents water that has an isotopic content lower than 144 ppm D/(D+H) which is the natural isotopic content of water. DDW is a non-toxic product. Knowing that deuterium content of water has a significant influence on living organisms, since 1996 NIR-DCIT ICSTI at Rm. Valcea cooperated with Romanian specialized instititutes for biological effects' evaluation of DDW. The investigations lead to the conclusion that DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects. Animals teated with DDW showed an increase of the resistance both to sub lethal and to lethal gamma radiation doses. DDW stimulates immune defense reactions. Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance in next growth stages. One can remark the favourable influence of DDW on biological process in plants in various ontogenetic stages. (authors)

  8. Historic Experiments in Radiationless Deuterium Fusion

    Science.gov (United States)

    Chubb, Talbot

    2001-04-01

    [1989-1991] Fleischmann & Pons observe excess heat in D2O electrolysis using Pd cathodes; confirmed in other studies. See "Excess Heat & Why Cold Fusion Research Has Prevailed" by Charles Beaudette. -- [1993] Fleischmann and Pons discover hours-long heat production in Pd cathodes after electrolysis turn-off. -- [1993, 1999] Miles & B. Bush, McKubre & Tanzella using mass spectrometers observe helium-4 in the electrolysis off-gas at rate of 1 helium atom per 24 MeV of released heat. -- [1994] Arata & Zhang develop DS-cathode, which produces months-long watts of excess heat 10 times in a row using Arata & Zhang protocol. -- [1999] DS-cathode technology is successfully transferred to SRI. -- [1998, 1999] Case observes and McKubre et al. verify heat and helium-4 generated in D2-loaded 0.5% Pd-on-carbon catalyst. -- [1997, 2000] Arata & Zhang observe by-product helium-3. Clarke collaborating with McKubre et al. observes helium-3 in materials from a previously-run DS cathode at helium-3/helium-4 ratio 10000 times atmospheric value. Time increase in helium-3 measures post-run tritium content, supports tritium observations by Will & Cedzynska (1991).

  9. Quantum Monte Carlo study of spin-polarized deuterium

    OpenAIRE

    Beslic, I.; Markic, L. Vranjes; Casulleras, J.; Boronat, J.

    2012-01-01

    The ground state properties of spin-polarized deuterium (D$\\downarrow$) at zero temperature are obtained by means of the diffusion Monte Carlo calculations within the fixed-node approximation. Three D$\\downarrow$ species have been investigated (D$\\downarrow_1$, D$\\downarrow_2$, D$\\downarrow_3$), corresponding respectively to one, two and three equally occupied nuclear spin states. Influence of the backflow correlations on the ground state energy of the systems is explored. The equilibrium den...

  10. X-ray powder diffraction from solid deuterium

    CERN Document Server

    Kawamura, H; Umemoto, S; Takemura, K; Ohishi, Y; Shimomura, O

    2002-01-01

    X-ray powder diffraction from solid deuterium was first observed under high pressure at SPring-8. At pressures up to 62 GPa and room temperature, three diffraction lines (100, 002, 101) of the hcp lattice were observed. The derived cell volume and the c/a ratio were consistent with single-crystal data. At 83 K and 94 GPa, three diffraction lines were also obtained and assigned to the hcp lattice.

  11. Blankets for tritium catalyzed deuterium (TCD) fusion reactors

    International Nuclear Information System (INIS)

    The TCD fusion fuel cycle - where the 3He from the D(D,n)3He reaction is transmuted, by neutron capture in the blanket, into tritium which is fed back to the plasma - was recently recognized as being potentially more promising than the Catalyzed Deuterium (Cat-D) fuel cycle for tokamak power reactors. It is the purpose of the present work to assess the feasibility of, and to identify promising directions for designing blankets for TCD fusion reactors

  12. Hard-core deuterium fibre Z-pinch

    International Nuclear Information System (INIS)

    A novel fusion concept is considered, related to present day deuterium fibre pinch experiments. The hard core is allowed to persist during the discharge, being completely ablated only at the end of the pulse. The Lawson requirement ητΕ> 1022M-3s for the catalysed D-D reaction is exceeded at a plasma temperature >30 keV by using high power generators with short pulse times of order a few ns. (au)

  13. A High Deuterium Abundance at z=0.7

    OpenAIRE

    Webb, J. K.; Carswell, R. F.; Lanzetta, K. M.; Ferlet, R.; Lemoine, M; Vidal-Madjar, A.; Bowen, D. V.

    1997-01-01

    Of the light elements, the primordial abundance of deuterium, (D/H)_p, provides the most sensitive diagnostic for the cosmological mass density parameter Omega_B. Recent high redshift (D/H) measurements are highly discrepant, although this may reflect observational uncertainties. The larger (D/H) values, which imply a low Omega_B and require the Universe to be dominated by non-baryonic matter (dynamical studies indicate a higher total density parameter), cause problems for galactic chemical e...

  14. Deuterium ingress at rolled joints in Embalse nuclear power plant

    International Nuclear Information System (INIS)

    Deuterium ingress model at the Rolled Joint has been extensively used for CANDU Nuclear Power Plants Operators in the Life Management of the Pressure Tubes. The importance of understanding the model is vital to avoid delayed hydride cracking at the Rolled Joint. This work reports the first step on develop the model presented on literature to be used in Argentinean CANDU 6, Embalse Nuclear Power Plant. (author)

  15. Deuterium behavior in first-wall materials for nuclear fusion

    OpenAIRE

    Bernard, Elodie

    2012-01-01

    Plasma-wall interactions play an important part while choosing materials for the first wall in future fusion reactors. Moreover, the use of tritium as a fuel will impose safety limits regarding the total amount present in the tokamak. Previous analyses of first-wall samples exposed to fusion plasma highlighted an in-bulk migration of deuterium (used as an analog to tritium) in carbon materials. Despite its limited value, this retention is problematic: contrary to co-deposited layers, it seems...

  16. Synthesis of deuterium-labelled compounds for FOTEK project

    International Nuclear Information System (INIS)

    In the FoTech project there have been utilized labelled compounds of stable isotopes as internal standards. Some of these compounds are commercially available (13C-labelled PCB congeners, 13C-labelled diethylstilbestrol for determination of anabolic steroids). Others, like D9-clenbuterol, D3-clenbuterol, D3-zeramol and D3-dimetridazol have been synthesized. General aspects of deuterium compounds labelling are considered. (EG)

  17. Deuterium Clusters Fusion Induced by the Intense Femtosecond Laser Pulse

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Jie; CHEN Jia-Bin; WANG Hong-Bin; JIAO Chun-Ye; HE Ying-Ling; WEN Tian-Shu; WEN Xian-Lun; CHEN Ming; ZHENG Zhi-Jian; GU Yu-Qiu; ZHANG Bao-Han; RHEE Yong-Joo; NAM Sung-Mo; HAN Jae-Min; RHEE Yong-Woo; YEA Kwon-Hae

    2007-01-01

    Neutrons (2.45 MeV) from deuterium cluster fusion induced by the intense femtosecond (30 fs) laser pulse are experimentally demonstrated. The average neutron yield 103 per shot is obtained. It is found that the yield slightly increases with the increasing laser spot size. No neutron can be observed when the laser intensity Ⅰ <4.3×1015 W/cm2.

  18. Deuteron charge radius from spectroscopy data in atomic deuterium

    CERN Document Server

    Pohl, Randolf; Udem, Thomas; Antognini, Aldo; Beyer, Axel; Fleurbaey, Hélène; Grinin, Alexey; Hänsch, Theodor W; Julien, Lucile; Kottmann, Franz; Krauth, Julian J; Maisenbacher, Lothar; Matveev, Arthur; Biraben, François

    2016-01-01

    We give a pedagogical description of the method to extract the charge radii and Rydberg constant from laser spectroscopy in regular hydrogen (H) and deuterium (D) atoms, that is part of the CODATA least-squares adjustment of the fundamental physical constants. We give a deuteron charge radius from D spectroscopy alone of 2.1415(45) fm. This value is independent of the proton charge radius, and five times more accurate than the value found in the CODATA Adjustment 10.

  19. Secondary deuterium isotope effects on epoxide methanolysis reactions

    International Nuclear Information System (INIS)

    Secondary kinetic deuterium isotope effects have recently come into widespread use as probes of reaction mechanism and transition state structure. Isotopic substitution at the reacting carbon gives rise to the so-called α effect due to differences in the energetics of out-of-plane bending of C-H and C-D bonds; these effects are usually interpreted in terms of changes in hybridization at the reacting carbon as the reaction processes. Alternately isotopic substitution at carbons adjacent to the reacting carbon leads to a β effect presumably arising from differences in the ability of C-H and C-D bands to interact with orbitals on the reacting carbon by means of hyperconjugation. In connection with mechanistic studies of the epoxide-diol pathway secondary deuterium isotope effects were used to compare epoxidation of olefins by cytochrome P-450 with olefin epoxidation by m-chloroperbenzoic acid. Observations of secondary deuterium isotope effects on the acid-and base-catalyzed methanolysis of p-nitrostyrene oxide, a chemical model system for the epoxide hydrase system were reported. This is the first observation of an α effect at the β carbon or a secondary effect at a neighboring carbon not attributable to hyperconjugation phenomena. Such effects might be expected but are not observed in the solvolysis of β-arglethyl tosylates and in the thermal cic-trans isomerization of cyclopropane derivatives. Another interesting result is the parallelism that the major reactions in acid and base both involve late or product-like transition states, while both minor reactions involve early or reactant-like transition states. These studies have shown that secondary deuterium isotope effects provide a sensitive and predictable probe for mechanistic studies of epoxide reactions. 3 tables

  20. Effects of deuterium depleted water on reproduction of Rainbow fish

    International Nuclear Information System (INIS)

    The paper refers to an isotopic composition used to prepare fecundating solutions for artificial reproduction of fish. The solution is constituted as a mixture of deuterium depleted water and natural water (whose isotopic concentration is of 85-90 ppm D/(D+H)) in which we can add activating and energizing substances. This fecundating solution ensures an improved fecundating level of fish roe, increase life index in the next growth up stages and increase fish resistance at special medium conditions. (authors)

  1. Influence of deuterium-depleted water on living organisms

    International Nuclear Information System (INIS)

    Deuterium-depleted water (DDW) production technique consists in the separation of deuterium from water by means of an continuos distillation process under a pressure value of about 133,3 mbar. Water that is used as basic material has an isotopic content of 144 ppm D/(D+H). DDW results as distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 NIR and DCIT Rm. Valcea, which is a DDW producer, co-operated with Romanian specialised institutes for biological effects' evaluation of DDW. These investigations led to the next conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tonus and vascular reactivity produced by the DDW persist after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and to lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defence mechanisms; - DDW stimulate immune defence reactions, represented by the opsonic, bactericidal and phagocyte capacity of the immune system, together with increase in the numbers of polymorphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favourable influence in embryo growth stage and resistance in next growth stages; - It was studied germination, growth and quantitative characters' variability at plants; one can remark the favourable influence of DDW on biological process at plants in various ontogenic stages. Further investigations are needed in order to establish the influence of deuterium-depleted water on living organisms. (authors)

  2. High resolution deuterium NMR studies of bacterial metabolism

    International Nuclear Information System (INIS)

    High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed

  3. High resolution deuterium NMR studies of bacterial metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Aguayo, J.B.; Gamcsik, M.P.; Dick, J.D.

    1988-12-25

    High resolution deuterium NMR spectra were obtained from suspensions of five bacterial strains: Escherichia coli, Clostridium perfringens, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus aureus. Deuterium-labeled D-glucose at C-1, C-2, and C-6 was used to monitor dynamically anaerobic metabolism. The flux of glucose through the various bacterial metabolic pathways could be determined by following the disappearance of glucose and the appearance of the major end products in the 2H NMR spectrum. The presence of both labeled and unlabeled metabolites could be detected using 1H NMR spectroscopy since the proton resonances in the labeled species are shifted upfield due to an isotopic chemical shift effect. The 1H-1H scalar coupling observed in both the 2H and 1H NMR spectra was used to assign definitively the resonances of labeled species. An increase in the intensity of natural abundance deuterium signal of water can be used to monitor pathways in which a deuteron is lost from the labeled metabolite. The steps in which label loss can occur are outlined, and the influence these processes have on the ability of 2H NMR spectroscopy to monitor metabolism are assessed.

  4. Emission of deuterium from SS 316L after plasma bombardment

    International Nuclear Information System (INIS)

    The understanding of the recycling (particle re-emission) behaviour of hydrogen isotopes from the first wall structures to the plasma of a fusion reactor is a crucial issue in plasma-wall interaction research, because the plasma performance will strongly depend on the time-scale and magnitude of this phenomenon. Deuterium recycling measurements from AISI 316L austenitic stainless steel surfaces have been performed in an experimental facility capable of reproducing particle flux densities and ion energies similar to those of ITER. The recycling flux has been evaluated. It is strongly dependent upon the impinging particle flux while target temperature and particle energy do not play a significant role. From these measurements a recombination coefficient for the system deuterium-AISI 316L has been calculated. The values are quite low, hence indicating that the AISI 316L sample target used was covered by an oxide layer that inhibits recombination. Moreover, the chemical composition of the recycling flux is pure molecular deuterium. ((orig.))

  5. Precision measures of the primordial abundance of deuterium

    CERN Document Server

    Cooke, Ryan; Jorgenson, Regina A; Murphy, Michael T; Steidel, Charles C

    2013-01-01

    We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = -2.87) damped Lyman-alpha system at z_abs = 3.06726 towards the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyman alpha transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias), and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H)_p = (2.53 +/- 0.04) x 10^-5, corresponding to a Universal baryon density 100 Omega_b h^2 = 2.202 +/- 0.045 for the standard model of Big Bang Nucleosynthesis. By combining our measure of (D/H)_p with observations of the cosmic microwave backg...

  6. Strain field of a buried oxide aperture

    Science.gov (United States)

    Kießling, F.; Niermann, T.; Lehmann, M.; Schulze, J.-H.; Strittmatter, A.; Schliwa, A.; Pohl, U. W.

    2015-02-01

    The strain field of an AlOx current aperture, fabricated by selective oxidation of an AlAs/GaAs layer buried in a circular GaAs mesa, is studied. Components of the strain tensor for a thin cross-section lamella cut out of such a structure are evaluated from dark-field electron holography, proving the validity of simulations based on linear elasticity. Simulation of the entire structure is utilized to prepare mesa surfaces with tailored strain fields for controlling the nucleation site of InGaAs quantum dots. The experimental proof of strain simulations allows estimating the magnitude of piezoelectricity, yielding for the studied mesa structures a piezoelectric potential up to 50 mV.

  7. Wind energy applications of synthetic aperture radar

    DEFF Research Database (Denmark)

    Badger, Merete

    planning as a supplement to on site measurements, which are costly and sparse, and model wind fields, which are not fully validated. Two applications of SAR measurements in offshore wind energy planning areaddressed here: the study of wind farm wake effects and the potential of using SAR winds in offshore......Synthetic aperture radars (SAR), mounted on satellites or aircraft, have proven useful for ocean wind mapping. Wind speeds at the height 10 m may be retrieved from measurements of radar backscatter using empirical model functions. The resulting windfields are valuable in offshore wind energy...... offshore wind resource assessment isinvestigated. The resource assessment is made through Weibull fitting to frequency observations of wind speed and requires at least 100 satellite observations per year for a given site of interest. Predictions of the energy density are very sensitive tothe wind speed and...

  8. Synthetic aperture tissue and flow ultrasound imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav

    simultaneously at every emission, which makes it possible to average over a large number of lines. This makes stationary echo canceling easier and significantly improves the velocity estimates. Only 8 emissions per plane are necessary to create the color flow map. Scanning 12 cm in depth, up to 800 planes can be......This Ph.D. project was carried out at the Center for Fast Ultrasound Imaging, Technical University of Denmark. The goal was to improve existing imaging techniques in order to make them suitable for real-time three-dimensional ultrasound scanning. This dissertation focuses on the synthetic aperture...... and beamformation methods are adequate for the imaging modalities in clinical use - the B-mode imaging of tissue structures, and the color mapping of blood flow. The acquisition time, however, is too long, and these methods fail to perform real-time three-dimensional scans. The synthetic transmit...

  9. Mathematical Problems in Synthetic Aperture Radar

    CERN Document Server

    Klein, Jens

    2010-01-01

    This thesis is concerned with problems related to Synthetic Aperture Radar (SAR). The thesis is structured as follows: The first chapter explains what SAR is, and the physical and mathematical background is illuminated. The following chapter points out a problem with a divergent integral in a common approach and proposes an improvement. Numerical comparisons are shown that indicate that the improvements allow for a superior image quality. Thereafter the problem of limited data is analyzed. In a realistic SAR-measurement the data gathered from the electromagnetic waves reflected from the surface can only be collected from a limited area. However the reconstruction formula requires data from an infinite distance. The chapter gives an analysis of the artifacts which can obscure the reconstructed images due to this problem. Additionally, some numerical examples are shown that point to the severity of the problem. In chapter 4 the fact that data is available only from a limited area is used to propose a new invers...

  10. Ultrasonic synthetic aperture imaging of defects

    International Nuclear Information System (INIS)

    Current reactor systems have been generally designed with limited facility for in-service inspection. Where ultrasonic crack detection and sizing techniques have been applied they appear to be functioning adequately. The purpose of this paper is to introduce a modification to conventional ultrasonic defect sizing which yields acoustic measurements of the dimensions of the defect in its plane parallel to the inspection surface. The technique retains the simplicity of a single probe to collect data, but achieves the effect of multidepth focussing by a particular signal processing procedure. The subject is discussed under the headings: ultrasonic focussing procedures; the basic principle of linear synthetic aperture focussing; the mechanics of the system; the capability of the system; comments and conclusion. (U.K.)

  11. A method for measuring the deuterium separation factors in palladium-hydrogen systems in view of tritium separation evaluation

    International Nuclear Information System (INIS)

    Full text: Palladium has a relatively large negative thermodynamic isotope effect (implied in the enrichment of the heavy isotope in gas phase and of the light isotope in solid phase). The separation factor is a quantitative measure of the mentioned thermodynamic isotope effect. Palladium - hydrogen systems were studied for many years and a great deal of information was accumulated on their structure, thermodynamic and kinetic characteristics of the hydrogen sorption and separation phenomena, but there is limited data available from which to develop a correlation between separation factor, temperature and solid phase composition. Existing data cover the phase (hydrogen and palladium coexisting as solid solution) and the plateau phase (of the palladium - hydrogen phase diagram (PCT curve). The authors developed a method and an experimental installation to investigate hydrogen-deuterium separation factors over a wider range of temperatures and compositions, covering the phase (hydride palladium - no dissolved hydrogen, only combined hydrogen). The palladium used in this study is of powder form: Merck Palladium black, 99.9%, APS 1.0 to 1.5 microns. In order to determine the separation factors, there are used FENWAL small bead thermistors operating in the self-heating mode as thermal conductivity sensors to measure the gas composition. The self-heating allows a power balance to be made between the thermistor bead, the surrounding gas and the Wheatstone bridge circuit used to measure the separation factors. For hydrogen - tritium and deuterium - tritium systems, separation factors were measured by other authors in the range of 10-9 to 10-7 mol percent tritium. Due to the difficulties inherent to the work with hydrogen - tritium and deuterium - tritium systems at higher stoichiometries, we used the obtained results on hydrogen- deuterium separation factors to evaluate the tritium separation. The knowledge of tritium separation in palladium - hydrogen systems phenomenon

  12. Application of a Pyroprobe-Deuterium NMR System: Deuterium Tracing and Mechanistic Study of Upgrading Process for Lignin Model Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Ben, Haoxi; Jarvis, Mark W.; Nimlos, Mark R.; Gjersing, Erica L.; Sturgeon, Matthew R.; Foust, Thomas D.; Ragauskas, Arthur J.; Biddy, Mary J.

    2016-04-21

    In this study, a pyroprobe-deuterium (2H) NMR system has been used to identify isotopomer products formed during the deuteration and ring opening of lignin model compounds. Several common model compounds for lignin and its upgraded products, including guaiacol, syringol, toluene, p-xylene, phenol, catechol, cyclohexane, methylcyclohexane, and methylcyclopentane, have been examined for selective ring opening. Similar pathways for upgrading of toluene and p-xylene has been found, which will undergo hydrogenation, methyl group elimination, and ring opening process, and benzene, cyclohexane, and methylcyclohexane have been found as major intermediates before ring opening. Very interestingly, the 2H NMR analysis for the deuterium-traced ring opening of catechol on Ir/..gamma..-Al2O3 is almost identical to the ring opening process for phenol. The ring opening processes for guaiacol and syringol appeared to be very complicated, as expected. Benzene, phenol, toluene, cyclohexane, and methylcyclohexane have been determined to be the major products.

  13. High Contrast Imaging with an Arbitrary Aperture: Active Correction of Aperture Discontinuities

    CERN Document Server

    Pueyo, Laurent

    2012-01-01

    We present a new method to achieve high-contrast images using segmented and/or on-axis telescopes. Our approach relies on using two sequential Deformable Mirrors to compensate for the large amplitude excursions in the telescope aperture due to secondary support structures and/or segment gaps. In this configuration the parameter landscape of Deformable Mirror Surfaces that yield high contrast Point Spread Functions is not linear, and non-linear methods are needed to find the true minimum in the optimization topology. We solve the highly non-linear Monge-Ampere equation that is the fundamental equation describing the physics of phase induced amplitude modulation. We determine the optimum configuration for our two sequential Deformable Mirror system and show that high-throughput and high contrast solutions can be achieved using realistic surface deformations that are accessible using existing technologies. We name this process Active Compensation of Aperture Discontinuities (ACAD). We show that for geometries si...

  14. Synthesis of deuterium-labelled compounds for FOTEK project; Syntese af deuterium-maerkede forbindelser til FOeTEK projektet

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, O.; Egsgaard, H.; Larsen, E. [Forskningscenter Risoe, Roskilde (Denmark)

    1996-06-01

    In the FoTech project there have been utilized labelled compounds of stable isotopes as internal standards. Some of these compounds are commercially available ({sup 13}C-labelled PCB congeners, {sup 13}C-labelled diethylstilbestrol for determination of anabolic steroids). Others, like D{sub 9}-clenbuterol, D{sub 3}-clenbuterol, D{sub 3}-zeramol and D{sub 3}-dimetridazol have been synthesized. General aspects of deuterium compounds labelling are considered. (EG).

  15. Shadow Enhancement in Synthetic Aperture Sonar Using Fixed Focusing

    NARCIS (Netherlands)

    Groen, J.; Hansen, R.E.; Callow, H.J.; Sabel, J.C.; Sæbø, T.O.

    2009-01-01

    Abstract—A shadow cast by an object on the seafloor is important information for target recognition in synthetic aperture sonar (SAS) images. Synthetic aperture imaging causes a fundamental limitation to shadow clarity because the illuminator is moved during the data collection. This leads to a blen

  16. Increasing the Dynamic Range of Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2014-01-01

    presented using synthetic aperture which increases the frame-to-frame signal correlation of the scatterer displacement while providing continuous data. In this paper, recursive synthetic aperture acquisition, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity...

  17. Synthetic Aperture Sequential Beamformation applied to medical imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-01-01

    Synthetic Aperture Sequential Beamforming (SASB) is applied to medical ultrasound imaging using a multi element convex array transducer. The main motivation for SASB is to apply synthetic aperture techniques without the need for storing RF-data for a number of elements and hereby devise a system...

  18. Velocity estimation using synthetic aperture imaging [blood flow

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Jensen, Jørgen Arendt

    2001-01-01

    Presented an approach for synthetic aperture blood flow ultrasound imaging. Estimates with a low bias and standard deviation can be obtained with as few as eight emissions. The performance of the new estimator is verified using both simulations and measurements. The results demonstrate that a fully...... functioning synthetic aperture scanner can be made...

  19. Apparatus and method for velocity estimation in synthetic aperture imaging

    DEFF Research Database (Denmark)

    2003-01-01

    The invention relates to an apparatus for flow estimation using synthetic aperture imaging. The method uses a Synthetic Transmit Aperture, but unlike previous approaches a new frame is created after every pulse emission. In receive mode parallel beam forming is implemented. The beam formed RF data...

  20. Second harmonic imaging using synthetic aperture sequential beamforming

    DEFF Research Database (Denmark)

    Du, Yigang; Rasmussen, Joachim; Jensen, Henrik;

    2011-01-01

    The paper investigates Second Harmonic Imaging (SHI) using Synthetic Aperture Sequential Beamforming (SASB). The investigation is made by an experimental Synthetic Aperture Real-time Ultrasound System (SARUS). A linear array transducer is used to scan 4 wires at the image depths of f22.5, 47.5, 72...