WorldWideScience

Sample records for high-flux low-energy ion

  1. Effect of high-flux, low-energy He+ ion irradiation on Ta as a plasma-facing material

    Science.gov (United States)

    Novakowski, T. J.; Tripathi, J. K.; Hassanein, A.

    2016-12-01

    The goal of this work is to assess Ta as a potential plasma-facing material for future fusion reactors in terms of its response to high-flux, low-energy He+ ion irradiation. Ta samples were irradiated with 100 eV He+ ions at various fluences up to 3.5 × 1025 ions m-2 while simultaneously heated at constant temperatures in the range 823-1223 K. SEM studies show that irradiated Ta surfaces undergo significant morphology changes that have a strong dependence on both ion fluence and sample temperature. Optical reflectivity complements SEM and demonstrates a vertical growth of surface structures with increasing fluence. Ex situ XPS and XRD both show significant oxidation of the irradiated Ta surfaces, giving further qualitative information on the extent of surface modification. Overall, these irradiation-induced structures on Ta are similar to early-stage “fuzz” structures observed in W. However, Ta exhibits a higher fluence threshold for structure formation. While Ta may have less desirable bulk properties (e.g., thermal conductivity) when compared to W, its higher resilience to He+ ion-induced surface modification suggests that surface thermal and mechanical properties may not degrade as quickly in extreme fusion environments; this quality may be a redeeming factor for Ta as a plasma-facing material.

  2. Nanostructured fuzz growth on tungsten under low-energy and high-flux He irradiation

    Science.gov (United States)

    Yang, Qi; You, Yu-Wei; Liu, Lu; Fan, Hongyu; Ni, Weiyuan; Liu, Dongping; Liu, C. S.; Benstetter, Günther; Wang, Younian

    2015-06-01

    We report the formation of wave-like structures and nanostructured fuzzes in the polycrystalline tungsten (W) irradiated with high-flux and low-energy helium (He) ions. From conductive atomic force microscope measurements, we have simultaneously obtained the surface topography and current emission images of the irradiated W materials. Our measurements show that He-enriched and nanostructured strips are formed in W crystal grains when they are exposed to low-energy and high-flux He ions at a temperature of 1400 K. The experimental measurements are confirmed by theoretical calculations, where He atoms in W crystal grains are found to cluster in a close-packed arrangement between {101} planes and form He-enriched strips. The formations of wave-like structures and nanostructured fuzzes on the W surface can be attributed to the surface sputtering and swelling of He-enriched strips, respectively.

  3. Optical characteristics of recrystallized tungsten mirrors exposed to low-energy, high flux D plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, A.I. [National Technical University ' Kharkiv Polytechnical Institute' , 61002 Kharkov (Ukraine); Alimov, V.Kh., E-mail: vkahome@mail.ru [Tritium Technology Group, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Galuza, A.A. [Institute of Electrophysics and Radiation Technologies, National Academy of Sciences of Ukraine, 61002 Kharkov (Ukraine); Isobe, K. [Tritium Technology Group, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Konovalov, V.G.; Ryzhkov, I.V. [Institute of Plasma Physics, National Scientific Center ' Kharkov Institute of Physics and Technology' , 61108 Kharkov (Ukraine); Savchenko, A.A.; Slatin, K.A. [National Technical University ' Kharkiv Polytechnical Institute' , 61002 Kharkov (Ukraine); Voitsenya, V.S. [Institute of Plasma Physics, National Scientific Center ' Kharkov Institute of Physics and Technology' , 61108 Kharkov (Ukraine); Yamanishi, T. [Tritium Technology Group, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2011-06-01

    The surface topography and optical properties of recrystallized tungsten exposed to a low-energy (38 eV/D), high flux (10{sup 22} D/m{sup 2s}) deuterium plasma with an ion fluence of 10{sup 26} D/m{sup 2} at various temperatures was investigated. It was found that the surface morphology weakly depends on the exposure temperature in the range 320-695 K with the exception of the narrow temperature region around 535 K, where large changes to all optical characteristics occurs. After plasma exposure at this temperature, the surface topography of the W sample is characterized by active blistering as has already been indicated in previous publications. The reflectance found in direct measurements at normal incidence drops in the wavelength interval 220-650 nm, whereas the estimations of reflectance using the ellipsometry data demonstrate some increase.

  4. Nanostructured light-absorbing crystalline CuIn{sub (1–x)}Ga{sub x}Se{sub 2} thin films grown through high flux, low energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Allen J.; Hebert, Damon; Rockett, Angus A. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, Illinois 61801 (United States); Shah, Amish B. [Center for Microanalysis of Materials, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Ave, Urbana, Illinois 61801 (United States); Bettge, Martin [Chemical Sciences and Engineering, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60438 (United States)

    2013-10-21

    A hybrid effusion/sputtering vacuum system was modified with an inductively coupled plasma (ICP) coil enabling ion assisted physical vapor deposition of CuIn{sub 1−x}Ga{sub x}Se{sub 2} thin films on GaAs single crystals and stainless steel foils. With <80 W rf power to the ICP coil at 620–740 °C, film morphologies were unchanged compared to those grown without the ICP. At low temperature (600–670 °C) and high rf power (80–400 W), a light absorbing nanostructured highly anisotropic platelet morphology was produced with surface planes dominated by (112){sub T} facets. At 80–400 W rf power and 640–740 °C, both interconnected void and small platelet morphologies were observed while at >270 W and above >715 °C nanostructured pillars with large inter-pillar voids were produced. The latter appeared black and exhibited a strong (112){sub T} texture with interpillar twist angles of ±8°. Application of a negative dc bias of 0–50 V to the film during growth was not found to alter the film morphology or stoichiometry. The results are interpreted as resulting from the plasma causing strong etching favoring formation of (112){sub T} planes and preferential nucleation of new grains, balanced against conventional thermal diffusion and normal growth mechanisms at higher temperatures. The absence of effects due to applied substrate bias suggests that physical sputtering or ion bombardment effects were minimal. The nanostructured platelet and pillar films were found to exhibit less than one percent reflectivity at angles up to 75° from the surface normal.

  5. Nanostructuring of molybdenum and tungsten surfaces by low-energy helium ions

    NARCIS (Netherlands)

    De Temmerman, G.; Bystrov, K.; Zielinski, J. J.; Balden, M.; Matern, G.; Arnas, C.; Marot, L.

    2012-01-01

    The formation of metallic nanostructures by exposure of molybdenum and tungsten surfaces to high fluxes of low energy helium ions is studied as a function of the ion energy, plasma exposure time, and surface temperature. Helium plasma exposure leads to the formation of nanoscopic filaments on the

  6. Simulation of low-energy ion scattering

    Science.gov (United States)

    Langelaar, M. H.; Breeman, M.; Mijiritskii, A. V.; Boerma, D. O.

    A new simulation program `MATCH' has been developed for a detailed analysis of low-energy ion scattering (LEIS) and recoiling data. Instead of performing the full calculation of the three-dimensional trajectories through the sample from the ion source towards the detector, incoming trajectories as well as reversed-time outgoing trajectories are calculated, separately. Finally, these trajectories are matched to obtain the yield. The program has been tested for spectra and azimuthal scans of scattering and recoiling events of various sample species in different scattering geometries.

  7. ECR ion source based low energy ion beam facility

    Indian Academy of Sciences (India)

    Mass analyzed highly charged ion beams of energy ranging from a few keV to a few MeV plays an important role in various aspects of research in modern physics. In this paper a unique low energy ion beam facility (LEIBF) set up at Nuclear Science Centre (NSC) for providing low and medium energy multiply charged ion ...

  8. Low energy ion-molecule reactions

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, J.M. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project is concerned with elucidating the dynamics of elementary ion-molecule reactions at collision energies near and below 1 eV. From measurements of the angular and energy distributions of the reaction products, one can infer intimathe details about the nature of collisions leading to chemical reaction, the geometries and lifetimes of intermediate complexes that govern the reaction dynamics, and the collision energy dependence of these dynamical features. The author employs crossed-beam low energy mass spectrometry technology developed over the last several years, with the focus of current research on proton transfer and hydrogen atom transfer reactions of te O{sup {minus}} ion with species such as HF, H{sub 2}O, and NH{sub 3}.

  9. Scanning ion microscopy with low energy lithium ions

    Energy Technology Data Exchange (ETDEWEB)

    Twedt, Kevin A. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Maryland NanoCenter, University of Maryland, College Park, MD 20742 (United States); Chen, Lei [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); McClelland, Jabez J., E-mail: jabez.mcclelland@nist.gov [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2014-07-01

    Using an ion source based on photoionization of laser-cooled lithium atoms, we have developed a scanning ion microscope with probe sizes of a few tens of nanometers and beam energies from 500 eV to 5 keV. These beam energies are much lower than the typical operating energies of the helium ion microscope or gallium focused ion beam systems. We demonstrate how low energy can be advantageous in ion microscopy when detecting backscattered ions, due to a decreased interaction volume and the potential for surface sensitive composition analysis. As an example application that demonstrates these advantages, we non-destructively image the removal of a thin residual resist layer during plasma etching in a nano-imprint lithography process. - Highlights: • We use an ion source based on photoionization of laser-cooled lithium atoms. • The ion source makes possible a low energy (500 eV to 5 keV) scanning ion microscope. • Low energy is preferred for ion microscopy with backscattered ions. • We use the microscope to image a thin resist used in nano-imprint lithography.

  10. Interaction between Low Energy Ions and the Complicated Organism

    Science.gov (United States)

    Yu, Zeng-liang

    1999-12-01

    Low energy ions exist widely in natural world, but people pay a little attention on the interaction between low energy ions and matter, it is even more out of the question of studying on the relation of low energy ions and the complicated organism. The discovery of bioeffect induced by ion implantation has, however, opened a new branch in the field of ion beam application in life sciences. This paper reports recent advances in research on the role of low energy ions in chemical synthesis of the biomolecules and application in genetic modification.

  11. Low Energy Ion Implanting of Silver Ion in Titanium

    Directory of Open Access Journals (Sweden)

    Fernanda Elisa Demore Palandi

    2014-08-01

    Full Text Available In modern medicine, biomaterials have been widely used as implants. Among biomaterials, titanium medical class is distinguished by its high degree of biocompatibility. However, orthoses and prostheses infected with post-implanted microorganisms require surgeries and medical interventions that are costly and treatment can take months. To combat infections associated with implants, the best strategy is to prevent them from occurring. One strategy is the silver ion implantation in titanium. In this work, silver ions were implanted at low energies (4 keV in medical titanium with the goal to take bactericide titanium surface and therefore, inhibit biofilm formation. The implantation was done using the Ion Plating equipment. After ion implantation, the samples were analyzing for Rutherford Backscattering Spectrometry, Glow-Discharge Optical Emission Spectroscopy and X-Ray Diffraction. The results show that the silver was implanted at depths up to 10 nm, corroborating simulation data. In addition, the strategy used in this work can be applied on an industrial scale due to the type of equipment used for the surface treatment.

  12. Negative ions as a source of low energy neutral beams

    Energy Technology Data Exchange (ETDEWEB)

    Fink, J.H.

    1980-01-01

    Little consideration has been given to the impact of recent developments in negative ion source technology on the design of low energy neutral beam injectors. However, negative ion sources of improved operating efficiency, higher gas efficiency, and smaller beam divergence will lead to neutral deuterium injectors, operating at less than 100 keV, with better operating efficiencies and more compact layouts than can be obtained from positive ion systems.

  13. Charge promotion of low-energy fragmentations of peptide ions.

    Science.gov (United States)

    Burlet, O; Orkiszewski, R S; Ballard, K D; Gaskell, S J

    1992-11-01

    We have examined the hypothesis that structural features which predispose to localization of charge at a strongly favored site are not conducive to the low-energy fragmentation of peptide ions via a multiplicity of pathways. Consistent with this proposal, it is demonstrated that the formation of N- or C-terminal pre-charged derivatives is detrimental to the formation of sequence-specific product ions following low-energy collisional activation. Protonation of pre-charged derivatives (yielding doubly charged ions) restores favorable fragmentation properties; the effect is attributed to the fragmentation-directing properties of the proton which may occupy one of several sites. Similarly, a doubly protonated peptide which incorporates a C-terminal arginine residue as a single strongly favored site of protonation exhibits favored low-energy fragmentations attributable to location of the second proton at one of several sites remote from the C-terminus.

  14. A Penning sputter ion source with very low energy spread

    Energy Technology Data Exchange (ETDEWEB)

    Nouri, Z., E-mail: znouri@uwo.c [Department of Physics and Astronomy, University of Western Ontario, London ON, N6A 3K7 (Canada); Li, R., E-mail: ruohong@triumf.c [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, V6T 2A3 (Canada); Holt, R.A., E-mail: rholt@uwo.c [Department of Physics and Astronomy, University of Western Ontario, London ON, N6A 3K7 (Canada); Rosner, S.D., E-mail: rosner@uwo.c [Department of Physics and Astronomy, University of Western Ontario, London ON, N6A 3K7 (Canada)

    2010-03-01

    We have developed a version of the Frankfurt Penning ion source that produces ion beams with very low energy spreads of approx3 eV, while operating in a new discharge mode characterized by very high pressure, low voltage, and high current. The extracted ions also comprise substantial metastable and doubly charged species. Detailed studies of the operating parameters of the source showed that careful adjustment of the magnetic field and gas pressure is critical to achieving optimum performance. We used a laser-fluorescence method of energy analysis to characterize the properties of the extracted ion beam with a resolving power of 1x10{sup 4}, and to measure the absolute ion beam energy to an accuracy of 4 eV in order to provide some insight into the distribution of plasma potential within the ion source. This characterization method is widely applicable to accelerator beams, though not universal. The low energy spread, coupled with the ability to produce intense ion beams from almost any gas or conducting solid, make this source very useful for high-resolution spectroscopic measurements on fast-ion beams.

  15. A cooler for intense low-energy ion beams

    CERN Document Server

    Varentsov, V L

    2002-01-01

    A new efficient cooling technique for intense low-energy ion beams is explored. The primary ions are directly injected through a converging-diverging nozzle into a cold expanding supersonic He carrier gas jet. There they adopt the temperature and overall velocity of the gas jet, creating an e sup - He sup + plasma in the slowing down process. In the RF-funnel that is placed on axis in the immediate vicinity of the nozzle exit plane the He sup + ions and electrons penetrate into the funnel walls and the He sup + ions have neutralized, while the desired more heavy ions are confined and focused inside the funnel. After reducing the plasma to a small level in the funnel the ion beam is further purified and compressed passing through a RFQ channel. Finally, the cooled low-emittance ion beam is extracted into high vacuum conditions through the skimmer placed behind the RFQ channel. The operation of the new ion beam cooling technique has been studied by means of numerical simulations. The results of calculations are...

  16. ECR ion source based low energy ion beam facility

    Indian Academy of Sciences (India)

    A nanogan type of ECR source based on a fully permanent magnet design was chosen for this purpose [3]. The ECR ion source along with all its peripheral electron- ics and vacuum components placed on a 200 kV high voltage platform provides multiply charged positive ions in a widely varying energy range from a few ...

  17. Reflection of low energy plasma ions from metal surfaces

    Science.gov (United States)

    Cuthbertson, J. W.; Langer, W. D.; Motley, R. W.

    1992-12-01

    Reflection of low energy (beam source based on acceleration and reflection of ions from a magnetically confined coaxial rf plasma source. The beam provides a large enough ion flux (over 4 A) to allow the characteristics of the reflected neutrals to be measured despite the inefficiency of detection. The energy distributions are measured by means of an electrostatic cylindrical mirror analyzer coupled with a quadrupole mass spectrometer. Energy distributions have been measured for oxygen, nitrogen and inert gas ions incident with from 10 to 70 eV reflected from amorphous metal surfaces of several compositions. The characteristics of particle reflection are commonly predicted in plasma modelling by use of simulation codes based on data from much higher incident energies. Measurements on this beam source allow the assumptions and approximations used in such codes to be tested. The predictions of the widely used TRIM code are compared to measured reflected energy distributions at low incident energies; significant differences are observed, particularly for lower target/projectile atomic mass ratios. The adequacy of the sequential binary collision approximation (used by TRIM) for modelling a collision process which at low energies is actually a simultaneous interaction between several atoms is tested by comparison with n-body trajectory calculations.

  18. Synthesis of sputtered thin films in low energy ion beams

    Science.gov (United States)

    Howson, R. P.

    1997-01-01

    Magnetron sputtering is a process which gives a highly energetic depositing species. The growing film can be further bombarded with ions of the heavy gas used for sputtering by directing a plasma of it onto the surface. This can be done quite simply by using an unbalanced magnetron. The immersion of an insulating or isolated substrate-film combination in this plasma leads to a self-bias of around 30 V appearing on it's surface and a bombardment of low energy ions of the sputtering gas of several milli-amps per square centimetre. If the residual gas contains a reactive component, to form a compound film, then the gas is made much more reactive and less is needed to form the stoichiometric film. This can take place in a continuously operating system made stable using partial pressure control of the reactive gas with plasma emission monitoring or something similar. It can also be operated when the process of deposition is separated in time from the process of reaction and is repeated to build the film. We have called this process successive-plasma-anodisation (SPA) and it can be achieved by mechanically transferring the substrate between two magnetrons, one to deposit the metal film and one, which is unbalanced, to provide an oxygen plasma. It can also be operated by pulsing the reactive gas under carefully controlled conditions. Examples are given of the synthesis of compound films using low energy ion bombardment with these techniques and it is demonstrated that excellent films of a large range of oxides and nitrides can be made.

  19. Low temperature magnetron sputter deposition of polycrystalline silicon thin films using high flux ion bombardment

    Science.gov (United States)

    Gerbi, Jennifer E.; Abelson, John R.

    2007-03-01

    We demonstrate that the microstructure of polycrystalline silicon thin films depends strongly on the flux of low energy ions that bombard the growth surface during magnetron sputter deposition. The deposition system is equipped with external electromagnetic coils which, through the unbalanced magnetron effect, provide direct control of the ion flux independent of the ion energy. We report the influence of low energy (thin films onto amorphous substrates. We use spectroscopic ellipsometry, Raman scattering, x-ray diffraction, and cross sectional transmission electron microscopy to analyze the film microstructure. We demonstrate that increasing the flux ratio of Ar+ ions to silicon neutrals (J+/J0) during growth by an order of magnitude (from 3 to 30) enables the direct nucleation of polycrystalline Si on glass and SiO2 coated Si at temperatures below 400°C. We discuss possible mechanisms for this enhancement of crystalline microstructure, including the roles of enhanced adatom mobility and the formation of shallow, mobile defects.

  20. ELISA - an electrostatic storage ring for low-energy ions

    Science.gov (United States)

    Pape Moeller, Soeren

    1997-05-01

    The design of a new type of storage ring for low-energy ions using electrostatic deflection and focusing devices is described. Electrostatic bends and quadrupoles are used since they are more efficient than magnetic ones for low-velocity heavy ions. Furthermore, electrostatic devices are more compact and easier to construct than magnetic devices. In comparison to an electromagnetic trap, one important advantage of the elecrostatic ring is the easy access to the circulating beam and its decay products. These and other features, e.g. no magnetic fields, makes such storage devices attractive for many atomic-physics experiments. Also neigboring fields as chemistry and biology might benefit from such an relatively inexpensive device. One important difference between an electrostatic and a magnetic ring is, that the longitudinal energy is not conserved for the electrostatic ring. The actual ring will have a race-track shape as defined by two straight sections each with two quadrupole doublets connected by 180-degrees bends. The bends will consist of 160-degrees spherical deflection plates surrounded by two parallel plate 10-degrees bends. The storage ring ELISA, currently being built, will have a circumference of 6 meters. The first beam tests will take place during summer 1996.

  1. Low-energy ions in the heavy ion cooler storage ring TSR

    Energy Technology Data Exchange (ETDEWEB)

    Artikova, Sayyora

    2012-05-02

    Deceleration is required to produce multicharged ion beams in the energy range from few keV to few MeV. It should be noted that the idea of decelerating ions in storage rings to lower energies dates back to H. Poth (1990). During deceleration of the charged particle beam, the influence of residual gas interaction, intrabeam scattering (IBS) as well as the incoherent space charge tune shift increase. These phenomena are mostly dominant in storage rings and become important at low velocities. The purpose of this PhD thesis is the generation of low-velocity ion beams by deceleration at the heavy ion cooler storage ring TSR and the study of the accompanying processes. Deceleration experiments concentrated on {sup 12}C{sup 6+} ions to identify the mechanisms which have an influence on the behavior and evolution of the beam. To explore the deceleration cycle, the {sup 12}C{sup 6+} ions are decelerated from 73.3 MeV to 9.77 MeV with an efficiency of 90%. To achieve this low energy two cooling steps at the initial and final energies of the beam are applied. Electron pre-cooling results in a dense ion beam where IBS has to be taken into account to describe the development of beam size during deceleration. An approximated model of IBS is proposed to interpret the experimental data. A decrease of the ion beam revolution frequency during the deceleration cycle reduces the beam current, which makes it difficult to measure with a common current transformer. Hence, new techniques are applied at low ion currents to determine the stored number of particles. Also incoherent tune shift effects, limiting the maximum number of stored particles are investigated. The availability of low-energy ion beams will expand the range of multicharged beam energies for precision studies of ion-atom collision in-ring MOT-Remi experiments.

  2. Effective doping of low energy ions into superfluid helium droplets

    Science.gov (United States)

    Zhang, Jie; Chen, Lei; Freund, William M.; Kong, Wei

    2015-01-01

    We report a facile method of doping cations from an electrospray ionization (ESI) source into superfluid helium droplets. By decelerating and stopping the ion pulse of reserpine and substance P from an ESI source in the path of the droplet beam, about 104 ion-doped droplets (one ion per droplet) can be recorded, corresponding to a pickup efficiency of nearly 1 out of 1000 ions. We attribute the success of this simple approach to the long residence time of the cations in the droplet beam. The resulting size of the doped droplets, on the order of 105/droplet, is measured using deflection and retardation methods. Our method does not require an ion trap in the doping region, which significantly simplifies the experimental setup and procedure for future spectroscopic and diffraction studies. PMID:26298127

  3. Low-energy ion implantation: Large mass fractionation of argon

    Science.gov (United States)

    Ponganis, K. V.; Graf, TH.; Marti, K.

    1993-01-01

    The isotropic signatures of noble gases in the atmospheres of the Earth and other planets are considerably evolved when compared to signatures observed in the solar wind. The mechanisms driving the evolution of planetary volatiles from original compositions in the solar accretion disk are currently poorly understood. Modeling of noble-gas compositional histories requires knowledge of fractionating processes that may have operated through the evolutionary stages. Since these gases are chemically inert, information on noble-gas fractionation processes can be used as probes. The importance of understanding these processes extends well beyond 'noble-gas planetology.' Trapped argon acquired by low-energy implantation (approximately less than 100 eV) into solids is strongly mass fractionated (approximately greater than or equal to 3 percent/amu). This has potential implications for the origin and evolution of terrestrial planet atmospheres.

  4. Analysis of low energy electron emission arising during slow multicharged ion-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Emmichoven, P.A.Z.v. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holified Heavy Ion Research Facility, Oak Ridge, TN 37831-6734 (United States)); Havener, C.C. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)); Hughes, I.G. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, TN 37831-6374 (United States)); Zehner, D.M.; Meyer, F.W. (Oak Ridge National Laboratory, Oak Ridge, TN 37831-6732 (United States))

    1993-06-05

    We have undertaken a search for low energy electrons expected to arise in low energy multicharged ion-surface interactions when electrons captured into Rydberg levels of the projectile are promoted to the continuum as the projectile impacts the surface. Measurements are presented for 30--100 keV N[sup 2+] -N[sup 6+] ions incident at 20[degree] with the surface on Cu(001) and Au(011) single crystals, for a series of observation angles.

  5. Analysis of low energy electron emission arising during slow multicharged ion-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Zeijlmans van Emmichoven, P.A.; Hughes, I.G. (Oak Ridge National Lab., TN (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, TN (United States)); Havener, C.C.; Zehner, D.M.; Meyer, F.W. (Oak Ridge National Lab., TN (United States))

    1992-01-01

    We have undertaken a search for low energy electrons expected to arise in low energy multicharged ion-surface interactions when electrons captured into Rydberg levels of the projectile are promoted to the continuum as the projectile impacts the surface. Measurements are presented for 30--100 keV N{sup 2+} -- N{sup 6+} ions incident at 20{sup o} with the surface on Cu(001) and Au(0ll) single crystals, for a series of observation angles.

  6. Corrosion behaviour of low energy, high temperature nitrogen ion ...

    Indian Academy of Sciences (India)

    S FLEGE. Technische Universität Darmstadt, Materials Science, Petersenstr. 23, 64287 Darmstadt, Germany. E-mail: flege@ca.tu-darmstadt.de. Ghoranneviss et al [1] have reported on nitrogen implantation into stainless steel and presented a secondary ion mass spectrometry (SIMS) measurement of the N and the CrN.

  7. Structuring of silicon with low energy focused ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Nebiker, P.W.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muehle, R. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    The defect production in silicon induced by focused ion beam irradiation as a function of energy and projectile mass has been investigated and compared to the measured sputter yield. The aim was to find optimal beam parameters for the structuring of semiconductors with a minimum amount of defects produced per removed atom. (author) 2 figs., 2 refs.

  8. Ion assisted deposition with low-energy ions for applications in modern optics

    CERN Document Server

    Kennedy, M

    1999-01-01

    realised by a process adaptation with UV-absorbing films. A further focal point are antireflective coatings on alkali halides optics for high-power CO sub 2 -lasers. Ion assisted deposition of NaF-films at extremely low ion energies (E sub i sub o sub n approx 5 eV) qualifies antireflective coatings with minimal absorption (alpha approx 1.5 cm sup - sup 1), high short-pulse damage threshold (50%-LIDT approx 60J/cm sup 2) and improved degradational stability. Main objective of this work is the development of ion assisted deposition processes without additional substrate heating for applications in precision and laser optics. New low-energy ion sources with ion energies below 100 eV were employed for the research work. Starting point of the process development are basic investigations on the ion assisted evaporation of fluoride and oxide thin film materials. The optimisation of the coating processes is primary done with the help of optical characterisation methods (spectral photometry, laser calorimetry, measur...

  9. DESIREE A Double Electrostatic Storage Ring for Low Energy Ion-Ion Collisions

    CERN Document Server

    Liljeby, Leif; Bagge, Lars; Blom, Mikael; Cederquist, Henrik; Danared, Håkan; Källberg, Anders; Larsson, Mats; Leontein, Sven; Löfgren, Patrik; Paal, Andras; Rensfelt, Karl-Gunnar; Schmidt, Henning T; Schmidt, Kjell; Simonsson, Ansgar; Skeppstedt, Örjan

    2005-01-01

    The advantages of storage rings with only electrostatic elements were first demonstrated in ELISA at Aarhus University and later in other places. At MSL and the Physics Department at Stockholm University the ideas have been developed further in the Double Electrostatic Storage Ion Ring ExpEriment, DESIREE. Beams of negative and positive atomic or molecular ions will be merged in a common straight section of two storage rings for studies of low energy collisions. The whole system may be cooled to below 20 K in order to relax internal excitations in stored molecules. This project is now fully financed and the final design work is in progress. A status report will be given in this paper together with a brief review of the planned physics program.

  10. Effect of the surface temperature on surface morphology, deuterium retention and erosion of EUROFER steel exposed to low-energy, high-flux deuterium plasma

    Directory of Open Access Journals (Sweden)

    M. Balden

    2017-08-01

    Full Text Available Samples of EUFROFER, a reduced activation ferritic martensitic steel, were exposed in the linear plasma device Pilot-PSI to a deuterium (D plasma with incident ion energy of ∼40eV and incident D flux of 2–6×1023D/m2s to fluences up to 1027D/m2 at surface temperatures ranging from 400K to 950K. The main focus of the study lays on the surface morphology changes dependent on the surface temperature and the surface composition evolution, e.g., the enrichment in tungsten; but also the erosion and the D retention are studied. The created surface morphology varies strongly with surface temperature from needle-like to corral-like structures. The visible lateral length scale of the formed structures is in the range of tens of nanometres to above 1µm and exhibits two thermal activated regimes below and above ∼770K with activation energies of 0.2eV and 1.3eV, respectively. The lateral variation of the enrichment of heavy elements on the surface is correlated to this surface morphology at least in the high temperature regime, independent of the origin of the enrichment (intrinsic from the sample or deposited by the plasma. Also the erosion exhibits temperature dependence at least above ∼770K as well as a fluence dependence. The amount of deuterium retained in the top 500nm is almost independent of the exposure temperature and is of the order of 1018D/m2, which would correspond to a sub-monolayer D coverage on the surface. The retained D in the volume summing up over the complete samples exceeds the D retained close to the surface by one order of magnitude.

  11. Low-energy ion outflow modulated by the solar wind energy input

    Science.gov (United States)

    Li, Kun; Wei, Yong; Andre, Mats; Eriksson, Anders; Haaland, Stein; Kronberg, Elena; Nilsson, Hans; Maes, Lukas

    2017-04-01

    Due to the spacecraft charging issue, it has been difficult to measure low-energy ions of ionospheric origin in the magnetosphere. A recent study taking advantage of the spacecraft electric potential has found that the previously 'hidden' low-energy ions is dominant in the magnetosphere. This comprehensive dataset of low-energy ions allows us to study the relationship between the ionospheric outflow and energy input from the solar wind (ɛ). In this study, we discuss the ratios of the solar wind energy input to the energy of the ionospheric outflow. We show that the ɛ controls the ionospheric outflow when the ɛ is high, while the ionospheric outflow does not systematically change with the ɛ when the ɛ is low.

  12. Space charge and working point studies in the CERN Low Energy Ion Ring

    CERN Document Server

    Huschauer, A; Hancock, S; Kain, V

    2017-01-01

    The Low Energy Ion Ring (LEIR) is at the heart ofCERN’s heavy ion physics programme and was designed toprovide the high phase space densities required by the exper-iments at the Large Hadron Collider (LHC). LEIR is the firstsynchrotron of the LHC ion injector chain and it receives aquasi-continuous pulse of lead ions (Pb54+) from Linac3, ex-ploiting a sophisticated multi-turn injection scheme in bothtransverse and longitudinal planes. Seven of these pulses areinjected and accumulated, which requires continuous elec-tron cooling (EC) at low energy to decrease the phase spacevolume of the circulating beam in between two injections.Subsequently, the coasting beam is adiabatically capturedin two bunches, which are then accelerated and extractedtowards the Proton Synchrotron (PS). Figure 1 shows theLEIR magnetic cycle and the different steps required forbeam production.

  13. Low energy ion beam modification of Cu/Ni/Si(100) surface

    Indian Academy of Sciences (India)

    1569–1573. c Indian Academy of Sciences. Low energy ion beam modification of Cu/Ni/Si(100) surface. S K PARIDAa, V R R MEDICHERLAa,∗. , D K MISHRAa, S CHOUDHARYb, V SOLANKIb and. SHIKHA VARMAb. aDepartment of Physics, Institute of Technical Education & Research, Siksha 'O' Anusandhan University,.

  14. A new computer code for quantitative analysis of low-energy ion scattering data

    NARCIS (Netherlands)

    Dorenbos, G; Breeman, M; Boerma, D.O

    We have developed a computer program for the full analysis of low-energy ion scattering (LEIS) data, i.e. an analysis that is equivalent to the full calculation of the three-dimensional trajectories of beam particles through a number of layers in the solid, and ending in the detector. A dedicated

  15. Specular reflection of low-energy ions during homoepitaxial growth of Ag(100)

    NARCIS (Netherlands)

    Langenaar, M.H.; Boerma, D.O

    1999-01-01

    In this paper a novel technique to study epitaxial growth is presented. Specular reflection of low-energy ions was used to characterize the surface during growth. Angular scans of the specular yield of 5.0 keV Ar+ scattered from a Ag(100) surface were obtained. The measurements were interpreted by

  16. Deep-level transient spectroscopy of low-energy ion-irradiated silicon

    DEFF Research Database (Denmark)

    Kolkovsky, Vladimir; Privitera, V.; Nylandsted Larsen, Arne

    2009-01-01

     During electron-gun deposition of metal layers on semiconductors, the semiconductor is bombarded with low-energy metal ions creating defects in the outermost surface layer. For many years, it has been a puzzle why deep-level transient spectroscopy spectra of the as-deposited, electron-gun evapor...

  17. Selected List of Low Energy Beam Transport Facilities for Light-Ion, High-Intensity Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L. R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2016-02-17

    This paper presents a list of Low Energy Beam Transport (LEBT) facilities for light-ion, high-intensity accelerators. It was put together to facilitate comparisons with the PXIE LEBT design choices. A short discussion regarding the importance of the beam perveance in the choice of the transport scheme follows.

  18. A pepper-pot emittance meter for low-energy heavy-ion beams

    NARCIS (Netherlands)

    Kremers, H. R.; Beijers, J. P. M.; Brandenburg, S.

    A novel emittance meter has been developed to measure the four-dimensional, transverse phase-space distribution of a low-energy ion beam using the pepper-pot technique. A characteristic feature of this instrument is that the pepper-pot plate, which has a linear array of holes in the vertical

  19. Study of Biological Effects of Low Energy Ion Implantation on Tomato and Radish Breeding

    Science.gov (United States)

    Liang, Qiuxia; Huang, Qunce; Cao, Gangqiang; Ying, Fangqing; Liu, Yanbo; Huang, Wen

    2008-04-01

    Biological effects of 30 keV low energy nitrogen ion implantation on the seeds of five types of tomato and one type of radish were investigated. Results showed that low energy ions have different effects on different vegetables. The whole dose-response curve of the germination ratio did not take on "the shape of saddle", but was a rising and falling waveform with the increase or decrease in ion implantation. In the vegetable of Solanaceae, two outstanding aberrant plants were selected from M1 of Henan No.4 tomato at a dose of 7 × 1017 nitrogen ions/cm2, which had thin-leaves, long-petal and nipple tip fruit stably inherited to M7. Furthermore the analysis of the isozyme showed that the activity of the mutant tomato seedling was distinct in quantity and color. In Raphanus sativus L., the aberrances were obvious in the mutant of radish 791 at a dose of 5 × 1017 nitrogen ions/cm2, and the weight of succulent root and the volume of growth were over twice the control's. At present, many species for breeding have been identified in the field and only stable species have been selected for the experiment of production. It is evident that the low energy ion implantation technology has clear effects on vegetables' genetic improvement.

  20. Enhancements to the Low-Energy Ion Facility at SUNY Geneseo

    Science.gov (United States)

    Barfield, Zachariah; Kostick, Steven; Nagasing, Ethan; Fletcher, Kurt; Padalino, Stephen

    2017-10-01

    The Low Energy Ion Facility at SUNY Geneseo is used for detector development and characterization for inertial confinement fusion diagnostics. The system has been upgraded to improve the ion beam quality by reducing contaminant ions. In the new configuration, ions produced by the Peabody Scientific duoplasmatron ion source are accelerated through a potential, focused into a new NEC analyzing magnet and directed to an angle of 30°. A new einzel lens on the output of the magnet chamber focuses the beam into a scattering chamber with a water-cooled target mount and rotatable detector mount plates. The analyzing magnet has been calibrated for deuteron, 4He+, and 4He2+ ion beams at a range of energies, and no significant hysteresis has been observed. The system can accelerate deuterons to energies up to 25 keV to initiate d-d fusion using a deuterated polymer target. Charged particle spectra with protons, tritons, and 3He ions from d-d fusion have been measured at scattering angles ranging from 55° to 135°. A time-of-flight beamline has been designed to measure the energies of ions elastically scattered at 135°. CEM detectors initiate start and stop signals from secondary electrons produced when low energy ions pass through very thin carbon foils. Funded in part by the U.S. Department of Energy through the Laboratory for Laser Energetics.

  1. Low-energy ion beam-based deposition of gallium nitride.

    Science.gov (United States)

    Vasquez, M R; Wada, M

    2016-02-01

    An ion source with a remote plasma chamber excited by a 13.56 MHz radio frequency power was used for low-energy broad ion beam extraction. Optical emission spectral analyses showed the sputtering and postionization of a liquid gallium (Ga) target placed in a chamber separated from the source bombarded by argon (Ar) plasma guided by a bent magnetic field. In addition, an E × B probe successfully showed the extraction of low-energy Ga and Ar ion beams using a dual-electrode extractor configuration. By introducing dilute amounts of nitrogen gas into the system, formation of thin Ga-based films on a silicon substrate was demonstrated as determined from X-ray diffraction and X-ray reflectivity studies.

  2. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions.

    Science.gov (United States)

    Valerio-Lizarraga, Cristhian A; Lallement, Jean-Baptiste; Leon-Monzon, Ildefonso; Lettry, Jacques; Midttun, Øystein; Scrivens, Richard

    2014-02-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H(-) beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  3. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

    2014-02-15

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  4. Joining of graphene flakes by low energy N ion beam irradiation

    Science.gov (United States)

    Wu, Xin; Zhao, Haiyan; Pei, Jiayun; Yan, Dong

    2017-03-01

    An approach utilizing low energy N ion beam irradiation is applied in joining two monolayer graphene flakes. Raman spectrometry and atomic force microscopy show the joining signal under 40 eV and 1 × 1014 cm-2 N ion irradiation. Molecular dynamics simulations demonstrate that the joining phenomenon is attributed to the punch-down effect and the subsequent chemical bond generation between the two sheets. The generated chemical bonds are made up of inserted ions (embedded joining) and knocked-out carbon atoms (saturation joining). The electronic transport properties of the joint are also calculated for its applications.

  5. Extraction characteristics of a low-energy ion beam system with a remote plasma chamber

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, M. R., E-mail: mrvasquez@coe.upd.edu.ph [Department of Mining, Metallurgical, and Materials Engineering, College of Engineering, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2016-02-15

    Low-energy argon beams were extracted from a dual-chamber ion source system. The first chamber is a quartz cylinder where dense inductively coupled plasmas were produced using 13.56 MHz radio frequency (rf) power. The discharge was driven into an adjacent chamber which acts as a reservoir for ion beam extraction using a dual-electrode extractor configuration. Extraction of ions from the second chamber with energies in the 100 eV range was achieved while minimizing fluctuations induced by the rf signal. A custom-built retarding potential analyzer was used to analyze the effectiveness of ion beam transport using the remote plasma chamber. Well-defined beams were extracted between 60 and 100 V extraction potentials at 50–100 W rf powers. An increase in rf power resulted in an increase in average ion energy, increase in ion current density while the energy spread remains constant.

  6. Carbon monoxide production in low energy oxygen ion bombardment of pyrolytic graphite and Kapton surfaces

    Science.gov (United States)

    Horton, C. C.; Eck, T. G.; Hoffman, R. W.

    1986-01-01

    The results of an investigtion of the interaction of low energy oxygen ions with pyrolytic graphite and Kapton surface are reported. CO molecules emitted from the surface as a result of the ion bombardment were detected by a mass spectrometer. Because the ion-induced signals were small compared to that arising from the CO background pressure in the vacuum system, the ion beam was modulated and the modulated component of the CO signal measured with a lock-in amplifier. The quantum yield (CO molecules emitted per incident oxygen ion) for graphite rose from 1.9 at 4.5 eV ion energy to 6.6 at 465 eV. Comparable yields were obtained for Kapton. The large size of the yields suggests contributions to the reaction process from the background O2 molecules in the vacuum system.

  7. Aluminium surface morphology behaviour under high-flux helium ion bombardment

    Science.gov (United States)

    Girka, O.; Bizyukov, O.; Bogatyrenko, S.; Bizyukov, I.

    2017-08-01

    Samples of aluminium with purity 99.99% wt are irradiated with helium ion beam under ITER-like conditions using FALCON ion source. Aluminium is used as the surrogate material for plasma-material interaction studies. Typical parameters during steady-state exposure are the following: helium ion flux is 2-4 × 1022 m-2 s-1, heat flux is above 1 MW m-2, average ion energy is of 2 keV, and the ion fluence is well above 1027 m-2. Investigation of the surface morphology with SEM shows the formation of the cone-like structures, which develop with fluence increasing. Surface features suddenly disappear at the fluence of 1.06 × 1027 m-2 and then start to grow again. Further fluence increase with step-by-step surface diagnostics shows periodical character of the surface structures growth and degradation.

  8. Measurements of low energy hydrogen ion effective sticking coefficients on titanium in the Wisconsin Levitated Octupole

    Energy Technology Data Exchange (ETDEWEB)

    Garner, H.; Post, R. S.

    1981-02-01

    The effective sticking coefficient for low energy (< 30 eV) hydrogen ions on titanium gettered aluminium walls has been measured in the Wisconsin Levitated Octupole. A value of greater than 0.75 was measured. The H/sub 2/ effective sticking coefficient for the same conditions is less than 0.01. Seventy-four percent of the wall area of the Octupole is gettered. The effects of recycling on plasma parameters is also discussed.

  9. Effect of low energy electron irradiation on DNA damage by Cu{sup 2+} ion

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hyung Ah; Cho, Hyuck [Dept. of Physics, Chungnam National University, Daejeon (Korea, Republic of); Park, Yeun Soo [Plasma Technology Research Center, National Fusion Research Institute, Gunsan (Korea, Republic of)

    2017-03-15

    The combined effect of the low energy electron (LEE) irradiation and Cu{sup 2+} ion on DNA damage was investigated. Lyophilized pBR322 plasmid DNA films with various concentrations (1–15 mM) of Cu{sup 2+} ion were independently irradiated by monochromatic LEEs with 5 eV. The types of DNA damage, single strand break (SSB) and double strand break (DSB), were separated and quantified by gel electrophoresis. Without electron irradiation, DNA damage was slightly increased with increasing Cu ion concentration via Fenton reaction. LEE-induced DNA damage, with no Cu ion, was only 6.6% via dissociative electron attachment (DEA) process. However, DNA damage was significantly increased through the combined effect of LEE-irradiation and Cu ion, except around 9 mM Cu ion. The possible pathways of DNA damage for each of these different cases were suggested. The combined effect of LEE-irradiation and Cu ion is likely to cause increasing dissociation after elevated transient negative ion state, resulting in the enhanced DNA damage. For the decrease of DNA damage at around 9-mM Cu ion, it is assumed to be related to the structural stabilization due to DNA inter- and intra-crosslinks via Cu ion.

  10. Enhanced supercapacitance behaviour of low energy ion beam reduced graphene oxide

    Science.gov (United States)

    Hareesh, K.; Shateesh, B.; Williams, J. F.; Asokan, K.; Phase, D. M.; Priya Madhuri, K.; Haram, S. K.; Dhole, S. D.

    2017-06-01

    This work reports the reduction of graphene oxide (GO) by low energy ions viz. 100 keV H+, 350 keV N+ and 200 keV Ar+ ions with fluences ranging from 5  ×  1013 to 1  ×  1015 ions cm-2. The x-ray diffractogram peak of GO decreased with increase in fluence and a broad peak around 25° appeared corresponding to reduced graphene oxide (rGO). Fourier transform infrared spectroscopic results showed the decrease in intensity of oxygen functional groups of GO confirming the reduction of GO which is further corroborated by x-ray photoelectron spectroscopic results. The ratio of D to G band increased with increase in fluence indicating the increase in disorder and formation of a large number of small sp2 domains. The work function was increased for low energy ion beam irradiated GO suggesting the storage of more charges. The irradiated GO showed enhanced supercapacitance behaviour with specific capacitance of rGO of 180, 195 and 202 F g-1 (scan rate 100 mV s-1) at a fluence 1  ×  1015 ions cm-2 for H+, N+ and Ar+ ions respectively. During irradiation, the ions might have deposited energy through electronic and nuclear energy loss results in the removal of oxygen functional groups from GO and enhancement in supercapacitance performance of rGO. It is also observed that GO irradiated by Ar ions showed more specific capacitance due to larger electronic energy loss than that of other ions.

  11. [Study on effect of seed vigor and agronomic characters of Cassia seeds implanted with low energy nitrogen ion beans].

    Science.gov (United States)

    Song, Mei; Wang, Xiang-Yang

    2012-07-01

    To study the effect of low energy nitrogen ion implantation on seed germination and agronomic characters. Different doses of low energy nitrogen ion implantation were implanted into fresh Cassia seed embryos. Seed germination, seedling growth and field agronomic characters were observed. The seeds after ion implantation showed significant reduction in germination energy, germination percentage and germination index, besides the significant decreasement in root length, fresh weight and vigor index of seedling. Plant height decreased despite the increase in grain size and grain weight. The low energy nitrogen ion implantation have significant effect on Cassia seeds, and being of great significance on Cassia artificial cultivation.

  12. Collective Thomson scattering system for determination of ion properties in a high flux plasma beam

    NARCIS (Netherlands)

    van der Meiden, H. J.; Vernimmen, J. W. M.; Bystrov, K.; Jesko, K.; Kantor, M. Y.; De Temmerman, G.; Morgan, T. W.

    2016-01-01

    A collective Thomson scattering system has been developed for measuring ion temperature, plasma velocity and impurity concentration in the high density magnetized Magnum-PSI plasma beam, allowing for measurements at low temperature (<5 eV) and high electron density >4 × 1020 m−3, while

  13. Effects of low energy ions on the optical, structural and chemical properties of polycarbonate

    Science.gov (United States)

    Raveesha P., M.; Nabhiraj P., Y.; Menon, Ranjini; Sanjeev, Ganesh

    2017-05-01

    Low energy Argon (Ar+) and Hydrogen (H+) ions were made to fall on the surface of Polycarbonate (PC) films. The depth profile calculations of ions on the material were carried out using Stopping and Range of Ions in Matter (SRIM-2008) code. The influence of bombarded ions with regard to the optical, structural and chemical properties was studied using UV-Visible spectroscopy (UV-Vis), X-Ray Diffraction (XRD) analysis and Fourier Transform Infra Red (FTIR) spectroscopy. The obtained results from UV-Visible study show a slight shift in the absorption edge towards higher wavelength region. The optical band gap found to be decreased after irradiation. XRD analysis showed minor changes in the structural parameters. The obtained FTIR spectra show reduction in the intensity of vibration bands for irradiated samples.

  14. Channel for Applied Investigations on Low Energy Ion Beams of Cyclotron DC-60

    CERN Document Server

    Gikal, B N; Borisenko, A N; Fateev, A A; Gulbekyan, G G; Kalagin, I V; Kazacha, V I; Kazarinov, N Yu; Kolesov, I V; Lebedev, N I; Lysukhin, S N; Melnikov, V N

    2006-01-01

    The channel intended for carrying out applied investigations on the low energy ion beams having the kinetic energy 25 $Z/A$ keV/a.u. and transported from the ECR-source to a target is worked out. The channel structure and parameters of all its optics elements are defined. The calculation results of different ion types transportation are given. It is shown that ions having the ratio of their mass to charge Z/A=2-20 can be transported in the worked out channel with enough high expected efficiency. At that the ion beam diameter on the target is $\\sim$40 mm. The characteristics of the basic optical elements of the channel are also given.

  15. Films deposited from reactive sputtering of aluminum acetylacetonate under low energy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, Felipe Augusto Darriba; Prado, Eduardo Silva; Cruz, Nilson Cristino da; Rangel, Elidiane Cipriano, E-mail: elidiane@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Caseli, Luciano [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas; Silva, Tiago Fiorini da; Tabacniks, Manfredo Harri [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Films were deposited from aluminum acetylacetonate (Al(acac)3 ) using a methodology involving reactive sputtering and low energy ion bombardment. The plasma was generated by the application of radiofrequency power to the powder containing electrode and simultaneously, negative pulses were supplied to the electrode where the substrates were attached. It was investigated the effect of the duty cycle of the pulses (Δ) on the properties of the coatings. Association of ion bombardment to the deposition process increased film thickness, structure reticulation and organic content. Ions from the deposition environment were implanted at the film-air interface or underneath it. Morphology and topography were altered depending on Δ. Considering the enhancement of Δ, it affected the flux of ions reaching the depositing interface and then the deposition rate, H content, crosslinking degree and surface microstructure. Alumina groups were detected in the infrared spectra, whereas the precipitation of amorphous alumina was confirmed by X-ray diffraction. (author)

  16. Biological Effects of Low Energy Ar+ Ion Bombardment on Silkworm Eggs: a Novel Animal Model

    Science.gov (United States)

    Xu, Jiaping; Wu, Yuejin; Liu, Xuelan; Yuan, Hang; Yu, Zengliang

    2009-06-01

    In this study, we found for the first time that silkworm eggs were able to survive in vacuum for a long period of time. Subsequently, low energy Ar+ ions with different energies and fluences were used to bombard silkworm eggs so as to explore the resulting biological effects. Results showed that (i) the exposure of silkworm eggs to vacuum within 10 min did not cause significant impact on the hatching rates, while the irradiation of silkworm eggs by Ar+ ions of 25 keV or 30 keV with fluences ranging from 2.6×2.6 × 1015 ion/cm2 to 8×2.6 × 1015 ion/cm2 caused a significant impact on the hatching rates, and the hatching rates decreased with the increase in the fluence and energy level; (ii) the irradiation of silkworm eggs by Ar+ ions of 30 keV with a fluence of 8×2.6 × 1015 ion/cm2 or 9×2.6 × 1015 ion/cm2 resulted in a noticeable etching on the egg shell surface which could be observed by a scanning electron microscope; and (iii) the irradiation of silkworm eggs by Ar+ ions of 30 keV with a fluence of 9×2.6 × 1015 ion/cm2 generated several mutant phenotypes which were observed in the 5th instar silkworms and a moth.

  17. Alternating bursts of low energy ions and electrons near the substorm onset

    Directory of Open Access Journals (Sweden)

    T. V. Kozelova

    2006-08-01

    Full Text Available The substorm associated behavior of the low energy particles (30 eV–28.5 keV near the earthward edge of the plasma sheet is examined using data from CRRES during the late growth and early expansion phases of a substorm on 12 March 1991 and their significance for the substorm onset mechanism is discussed. In this substorm, the CRRES was located on L ~6.3 and ~20° westward of the substorm onset and observed the sequence of the alternating bursts of the low energy ions and electrons. The bursts of the 0.633–9.6 keV ions occurred 1–2 min before the (7.31–21.7 keV electron bursts. The first ion burst happened 2min before the substorm onset, at the moment of weak brightening of the most equatorial pre-breakup arc near the latitude ~62°. The alternation of the ion and electron bursts may be a signature of a drift-Alfvén ballooning instability on the inner edge of the plasma sheet near substorm onset.

  18. Development of a low-energy radioactive ion beam facility for the MARA separator

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, Philippos, E-mail: philippos.papadakis@jyu.fi; Moore, Iain; Pohjalainen, Ilkka; Sarén, Jan; Uusitalo, Juha [University of Jyväskylä, Department of Physics (Finland)

    2016-12-15

    A low-energy radioactive ion beam facility for the production and study of nuclei produced close to the proton drip line is under development at the Accelerator Laboratory of the University of Jyväskylä, Finland. The facility will take advantage of the mass selectivity of the recently commissioned MARA vacuum-mode mass separator. The ions selected by MARA will be stopped and thermalised in a small-volume gas cell prior to extraction and further mass separation. The gas cell design allows for resonance laser ionisation/spectroscopy both in-gas-cell and in-gas-jet. The facility will include experimental setups allowing ion counting, mass measurement and decay spectroscopy.

  19. Nondissociative low energy electron attachment to C2Cl4:C2Cl4- ion lifetime

    Science.gov (United States)

    Suess, L.; Parthasarathy, R.; Dunning, F. B.

    2003-04-01

    The lifetimes of long-lived parent anions formed by nondissociative electron attachment to C2Cl4 are investigated using Rydberg atom techniques. The ions are created through electron transfer in collisions with K(np) Rydberg atoms and their lifetimes are measured using both time-of-flight techniques and a permanent magnet Penning trap designed specifically for heavy ion storage. The data show that low-energy electron attachment to C2Cl4 leads to the formation of C2Cl4- ions with a broad range of lifetimes extending from ˜3 to ˜130 μs, which is attributed to capture by molecules in different initial vibrational states.

  20. Development of a low-energy radioactive ion beam facility for the MARA separator

    Science.gov (United States)

    Papadakis, Philippos; Moore, Iain; Pohjalainen, Ilkka; Sarén, Jan; Uusitalo, Juha

    2016-12-01

    A low-energy radioactive ion beam facility for the production and study of nuclei produced close to the proton drip line is under development at the Accelerator Laboratory of the University of Jyväskylä, Finland. The facility will take advantage of the mass selectivity of the recently commissioned MARA vacuum-mode mass separator. The ions selected by MARA will be stopped and thermalised in a small-volume gas cell prior to extraction and further mass separation. The gas cell design allows for resonance laser ionisation/spectroscopy both in-gas-cell and in-gas-jet. The facility will include experimental setups allowing ion counting, mass measurement and decay spectroscopy.

  1. Particle reflections of low energy light ions from a vanadium alloy (V-4Cr-4Ti)

    Energy Technology Data Exchange (ETDEWEB)

    Yamaoka, H. [Harima Institute, RIKEN The Institute of Physical and Chemical Research, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan)]. E-mail: yamaoka@spring8.or.jp; Tanaka, N. [Tohoku University, Sendai 980-8579 (Japan)]. E-mail: nozomi.tanaka@ppl2.qse.tohoku.ac.jp; Matsumoto, Y. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Nishiura, M. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Tsumori, K. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Takeuchi, S. [Tohoku University, Sendai 980-8579 (Japan); Sugawara, H. [Tohoku University, Sendai 980-8579 (Japan); Shinto, K. [Tohoku University, Sendai 980-8579 (Japan); Okamoto, A. [Tohoku University, Sendai 980-8579 (Japan); Sasao, M. [Tohoku University, Sendai 980-8579 (Japan); Wada, M. [Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2007-06-15

    The angular distributions and energy spectra of positive and negative ions reflected from a vanadium alloy (V-4Cr-4Ti) bombarded by beams of low energy (1-2 keV) ions of H, He, and O were measured. The intensities of H{sup +} or H{sup -} produced from reflection of 2 keV H{sup +} beam at the surface of vanadium alloy showed the maxima at the angles closer to the surface normal from the mirror reflection angle, compared with Mo and W samples. The time dependence of the angular distributions of the reflected H{sup +} or H{sup -} ions measured at the sample temperature of about 240-260 {sup o}C showed a shift of the peak in the angular distribution to the mirror reflection angle.

  2. Radiation damage in urania crystals implanted with low-energy ions

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tien Hien, E-mail: tien-hien.nguyen@u-psud.fr [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM – UMR 8609), CNRS-IN2P3-Université Paris-Sud, Bâtiments 104-108, 91405 Orsay Campus (France); Garrido, Frédérico; Debelle, Aurélien; Mylonas, Stamatis [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM – UMR 8609), CNRS-IN2P3-Université Paris-Sud, Bâtiments 104-108, 91405 Orsay Campus (France); Nowicki, Lech [The Andrzej Soltan Institute for Nuclear Studies, Hoza 69, 00-681 Warsaw (Poland); Thomé, Lionel; Bourçois, Jérôme; Moeyaert, Jérémy [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM – UMR 8609), CNRS-IN2P3-Université Paris-Sud, Bâtiments 104-108, 91405 Orsay Campus (France)

    2014-05-01

    Implantations with low-energy ions (470-keV Xe and 500-keV La with corresponding ion range Rp ∼ 85 nm and range straggling ΔRp ∼ 40 nm) have been performed to investigate both radiation and chemical effects due to the incorporation of different species in UO{sub 2} (urania) crystals. The presence of defects was monitored in situ after each implantation fluence step by the RBS/C technique. Channelling data were analysed afterwards by Monte-Carlo simulations with a model of defects involving (i) randomly displaced atoms (RDA) and (ii) distorted rows, i.e. bent channels (BC). While increasing the ion fluence, the accumulation of RDA leads to a steep increase of the defect fraction in the range from 4 to 7 dpa regardless of the nature of bombarding ions followed by a saturation plateau over a large dpa range. A clear difference of 6% in the yield of saturation plateaus between irradiation with Xe and La ions was observed. Conversely, the evolutions of the fraction of BC showed a similar regular increase with increasing ion fluence for both ions. Moreover, this increase is shifted to a larger fluence in comparison to the sharp increase step of RDA. This phenomenon indicates a continuous structural modification of UO{sub 2} crystals under irradiation unseen by the measurement of RDA.

  3. A kinematic coincidence technique for the study of low-energy heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Corradi, L.; Montagnoli, G.; Napoli, D.R.; Spolaore, P.; Stefanini, A.M.; Xu Jincheng (Istituto Nazionale di Fisica Nucleare, Padua (Italy). Lab. di Legnaro); Beghini, S.; Scarlassara, F.; Segato, G.F.; Soramel, F. (Padua Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy)); Signorini, C. (Salerno Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Padua (Italy))

    1990-12-10

    A setup for kinematic coincidences has been developed for the study of low-energy binary heavy-ion reactions. It consists of a position-sensitive silicon detector, and a counter telescope with microchannel plates detectors and a conventional {Delta}E-E ionization chamber. The solid angle is around 0.6 msr. By measuring the time of flight of one of the ions, and both correlated scattering angles, we achieve mass and Q-value resolutions of {Delta}A/A{approx equal}1/120 FWHM and {Delta}Q{approx equal}900 keV, respectively, for the elastic scattering of {sup 58}Ni+{sup 64}Ni near the barrier. (orig.).

  4. Emission of low-energy electrons from multicharged ions interacting with metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zeijlmans van Emmichoven, P.A. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831-6374 (United States)); Havener, C.C. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States)); Hughes, I.G. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831-6374 (United States)); Zehner, D.M.; Meyer, F.W. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States))

    1993-05-01

    Low-energy electron spectra are reported for 60- and 100-keV multicharged ions interacting at an incident angle of 20[degree] with Au and Cu surfaces. Analysis of the spectra indicate that at least two features contribute. The first feature represents the major contribution to the total electron yield and consists of 5--10-eV electrons emitted over a wide range of angles. The angular distribution of this component is not symmetric with respect to the surface normal, but shows an increase in the forward direction of the incident ions. It will be shown that this component arises predominantly from below the surface. Possible potential-emission mechanisms which may contribute will be discussed. The second feature, which constitutes a minor part of the overall electron emission, occurs at higher electron energies ([similar to]20 eV), and is peaked at the extreme forward angles. Binary encounters between incident ions and metal electrons at the surface-vacuum interface will be shown to describe the main features of this component. At even higher electron energies ([gt]40 eV) the spectra show a tail whose slope does not depend on either the initial charge state or kinetic energy of the incident ions. The invariance with kinetic energy is in sharp contrast with the corresponding experimental results from ion-atom collisions.

  5. Design of an energy analyzer for low energy 1+ charged ion beams at RISP Project

    Science.gov (United States)

    Boussaid, R.; Park, Y. H.; Moon, J. Y.

    2017-11-01

    Accurate measurement of the energy spread with a compact device has been accomplished by developing a new prototype of a retarding field energy analyzer (RFEA). The device is capable of handling all kinds of low energy mono-charged ion beams at RISP Project. Numerical simulations have been performed in order to study and evaluate dependency of RFEA energy resolution to beam emittance, beam energy, beam energy spread, space charge effects, and most significantly the optics system. Simulation results have shown that the use of developed optics system with particular voltage applied on the focusing cylinder and suitable positioning of the retarding grid may lead to high efficiency energy resolutions not exceeding 0.31 eV for beam energy going up to 20 keV . Small errors on the measured energy spread are obtained despite the presence of degradations stemming from various energy resolution dependencies. Typical mono-charged ion beams delivered from ion trap devices, ISOL beam-line and stable ion sources have been studied. The error on the optimum measured energy spread for beams delivered from ion trap devices is 5 ~ 10% owing to beam emittances. For a larger beam size, delivered from an ISOL beam-line, a larger error occurs on the measured energy spread at around 23.5%. The energy spread of ion beams delivered from stable ion sources with good optical quality relative to the ISOL sources can be measured with an error around 21.7%. This prototype enables accurate measurement of the average beam energy with an error around 1.5 eV per 20 keV beam energy.

  6. Low-energy plasma immersion ion implantation to induce DNA transfer into bacterial E. coli

    Energy Technology Data Exchange (ETDEWEB)

    Sangwijit, K. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Sarapirom, S. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Bang Khen, Chiang Mai 50290 (Thailand); Pitakrattananukool, S. [School of Science, University of Phayao, Muang, Phayao 56000 (Thailand); Anuntalabhochai, S. [Biotechnology Unit, University of Phayao, Muang, Phayao 56000 (Thailand)

    2015-12-15

    Plasma immersion ion implantation (PIII) at low energy was for the first time applied as a novel biotechnology to induce DNA transfer into bacterial cells. Argon or nitrogen PIII at low bias voltages of 2.5, 5 and 10 kV and fluences ranging from 1 × 10{sup 12} to 1 × 10{sup 17} ions/cm{sup 2} treated cells of Escherichia coli (E. coli). Subsequently, DNA transfer was operated by mixing the PIII-treated cells with DNA. Successes in PIII-induced DNA transfer were demonstrated by marker gene expressions. The induction of DNA transfer was ion-energy, fluence and DNA-size dependent. The DNA transferred in the cells was confirmed functioning. Mechanisms of the PIII-induced DNA transfer were investigated and discussed in terms of the E. coli cell envelope anatomy. Compared with conventional ion-beam-induced DNA transfer, PIII-induced DNA transfer was simpler with lower cost but higher efficiency.

  7. Low-energy nuclear astrophysics studies at the Multicharged Ion Research Facility

    Science.gov (United States)

    Febbraro, Michael; Pain, Steven; Bannister, Mark; Deboer, Richard; Chipps, Kelly; Havener, Charles; Peters, Willan; Ummel, Chad; Smith, Michael; Temanson, Eli; Toomey, Rebecca; Walter, David

    2017-09-01

    As low-energy nuclear astrophysics progresses toward measuring reaction cross sections in the stellar burning regimes, a worldwide effort is underway to continue these measurements at underground laboratories to achieve the requisite ultra-low-background environment. These facilities are crucial for providing the required low-background environments to perform such measurements of astrophysical importance. While advances have been made in the use of accelerators underground, of equal importance is the detectors, high-current targets, and techniques required to perform such measurements. With these goals in mind, a newly established astrophysics beamline has been built at the Multicharged Ion Research Facility (MIRF) located at Oak Ridge National Laboratory. The unique capabilities of MIRF will be demonstrated through two recent low-energy above-ground measurements of the dominant s-process neutron source 13C(α,n)16O and associated beam-induced background source 13C(d,n)14N. This material is based upon work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics. Research sponsored by the LDRD Program of ORNL, managed by UT-Battelle, LLC, for the U.S. DOE.

  8. Silkworm eggs: An ideal model for studying the biological effects of low energy Ar{sup +} ion interaction in animals

    Energy Technology Data Exchange (ETDEWEB)

    Ling Lin; Liu Xuelan [School of Life Sciences, Anhui Agricultural University, Hefei 230031 (China); Xu Jiaping, E-mail: jiapingxu@163.com [School of Life Sciences, Anhui Agricultural University, Hefei 230031 (China); You Zhengying; Zhou Jingbo [School of Life Sciences, Anhui Agricultural University, Hefei 230031 (China)

    2011-09-15

    Highlights: {yields} Low energy Ar{sup +} ion beam interactions with silkworm eggs. {yields} Ion beam bombardment as a novel method for gene transfer in silkworm. {yields} Provide evidence for studying the mechanisms of ion beam interaction in animals. - Abstract: The object of the current work was to study low energy Ar{sup +} ion beam interactions with silkworm eggs and thus provide further understanding of the mechanisms involved in ion bombardment-induced direct gene transfer into silkworm eggs. In this paper, using low-energy Ar{sup +} ion beam bombardment combined with piggyBac transposon, we developed a novel method to induce gene transfer in silkworm. Using bombardment conditions optimized for egg-incubation (25 keV with ion fluences of 800 x 2.6 x 10{sup 15} ions/cm{sup 2} in dry state under vacuum), vector pBac{l_brace}3 x P3-EGFPaf{r_brace} and helper plasmid pHA3pig were successfully transferred into the silkworm eggs. Our results obtained from by PCR assay and genomic Southern blotting analysis of the G1 generations provide evidence that low-energy ion beam can generate some craters that play a role in acting as pathways of exogenous DNA molecules into silkworm eggs.

  9. Studies of low-energy heavy-ion reactions at LNL

    Energy Technology Data Exchange (ETDEWEB)

    Stefanini, A.M.; Ackermann, D.; Corradi, L.; He, J.H. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.P. [Istituto Nazionale di Fisica Nucleare, Padua (Italy)

    1995-02-01

    Recent experimental investigations on low-energy heavy-ion reaction dynamics performed at Legnaro are reviewed. A short description is given of the setup which enables the study of elastic scattering and of quasielastic transfer reactions, as well as of fusion reactions. After a brief hint on the perspectives in the field of multinucleon transfer, the main part of the lecture is dedicated to the fusion reactions for which recent developments, like the studies of barrier distributions and the theoretical approach using the Interaction Boson Model, have lead to a renewed interest. Some results obtained by our group are presented for the system {sup 32}S+ {sup 58,64}Ni, {sup 16}O+{sup 194}Pt (sensitivity to the target deformation) and {sup 58}Ni+{sup 60}Ni (evidence for multiphonon excitation in subbarrier fusion). (author). 24 refs, 8 figs.

  10. Alternating bursts of low energy ions and electrons near the substorm onset

    Energy Technology Data Exchange (ETDEWEB)

    Kozelova, T.V.; Kozelov, B.V. [Polar Geophysical Institute, Apatity, Murmansk region (Russian Federation); Lazutin, L.L. [Moscow State Univ. (Russian Federation). Scobeltsyn Insitute for Nuclear Physics, Russia Space Science Laboratory; Meredith, N. [Univ. College, London (United Kingdom). Mullard Space Science Laboratory; Danielides, M.A. [Oulu Univ. (Finland). Space Physics Group

    2006-07-01

    The substorm associated behavior of the low energy particles (30 eV-28.5 keV) near the earthward edge of the plasma sheet is examined using data from CRRES during the late growth and early expansion phases of a substorm on 12 March 1991 and their significance for the substorm onset mechanism is discussed. In this substorm, the CRRES was located on L {proportional_to}6.3 and {proportional_to}20 westward of the substorm onset and observed the sequence of the alternating bursts of the 0.633-9.6 keV ions occured 1-2 min before the (7.31-21.7 keV) electron bursts. The first ion burst happened 2 min before the substorm onset, at the moment of weak brightening of the most equatorial pre-breakup are near the latitude {proportional_to}62 . The alternation of the ion and electron bursts may be a signature of a drift-Alven ballooning instability on the inner edge of the plasma sheet near substorm onset.

  11. Quightness: A proposed figure of merit for sources of low-energy, high-charge-state ions

    Energy Technology Data Exchange (ETDEWEB)

    Schmieder, R.W. (Sandia National Laboratories, Livermore, California 94551 (US))

    1990-03-01

    A variety of ion sources, including the EBIS and ECRIS, are distinguished by their ability to produce low-energy ions of very high charge state. It would be useful to have some figure of merit that is particularly sensitive to this performance. I propose here such a quantity, called Quightness,'' which is related to brightness but which enhances the contrast between sources supplying multicharged ions of low energy. The rationale for introducing this quantity, its etymology and relationship to other figures of merit, and some representative values are presented.

  12. Synthesis of periodic plasmonic microstructures with copper nanoparticles in silica glass by low-energy ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, A.L. [Laser Zentrum Hannover e.V., Hannover (Germany); Kazan Physical-Technical Institute of RAS, Kazan (Russian Federation); Kazan Federal University, Kazan (Russian Federation); Galyautdinov, M.F.; Nuzhdin, V.I.; Valeev, V.F. [Kazan Physical-Technical Institute of RAS, Kazan (Russian Federation); Evlyukhin, A.B. [Laser Zentrum Hannover e.V., Hannover (Germany); Kama State Academy of Engineering and Economics, Naberezhnye Chelny (Russian Federation); Osin, Y.N. [Kazan Federal University, Kazan (Russian Federation); Evlyukhin, E.A. [Universite Paris 13, Institut Galilee, Villetaneuse (France); Kiyan, R.; Chichkov, B.N. [Laser Zentrum Hannover e.V., Hannover (Germany); Kavetskyy, T.S. [Drohobych Ivan Franko State Pedagogical University, Drohobych (Ukraine)

    2013-04-15

    Ion implantation was used to locally modify the surface of silica glass to create periodic plasmonic microstructures with Cu nanoparticles. Nanoparticles were synthesized by Cu-ion irradiation of the silica glass at the ion energy of 40 keV, dose of 5 x 10{sup 16} ions/cm{sup 2} and current density of 5 {mu}A/cm{sup 2}. This procedure involves low-energy ion implantation into the glass through a mask placed at the surface. Formation of nanoparticles was observed by optical spectroscopy and atomic force microscopy. The presented results clearly demonstrate how the low-energy ions can be used for the fabrication of photonic microstructures on dielectric surfaces in a single-step process. (orig.)

  13. Low-energy outer-shell photo-detachment of the negative ion of aluminum

    Science.gov (United States)

    Gedeon, Viktor; Gedeon, Sergej; Lazur, Vladimir; Nagy, Elizabeth; Zatsarinny, Oleg; Bartschat, Klaus

    2018-02-01

    We investigate the photodetachment of the negative ion of aluminum, initially both in the {{Al}}-{(3{s}23{p}2)}3P ground state and the excited 1 D state. A multiconfiguration Hartree–Fock method with nonorthogonal, term-dependent orbitals is used to generate accurate initial bound-state and final continuum-state wavefunctions. The collision of the ejected electron in the field of the residual ion is described by the B-spline R-matrix method for photon energies ranging from threshold to 12 eV. All principal scattering channels for photodetachment from both the 3p and 3s orbitals are included in the close-coupling expansion. We predict a number of prominent resonance features, whose verification presents new challenges in studies of this highly correlated process. Partial cross sections, together with the contributions of the principal scattering channels, are discussed in order to classify the resonance structure. The predicted cross sections are expected to be the most comprehensive and accurate currently available dataset for photodetachment of Al‑ at low energies.

  14. Surface morphology and deuterium retention in tungsten exposed to high flux D plasma at high temperatures

    NARCIS (Netherlands)

    Jia, Y. Z.; De Temmerman, G.; Luo, G. N.; Xu, H.Y.; Li, C.; Fu, B. Q.; Liu, W.

    2015-01-01

    Surface modifications and deuterium retention induced in tungsten by high fluxes (1024 m−2 s−1) low energy (38 eV) deuterium ions were studied as a function of surface temperature. Blister formation was studied by scanning electron microscopy and electron backscatter diffraction, while deuterium

  15. Treatment of PVC using an alternative low energy ion bombardment procedure

    Energy Technology Data Exchange (ETDEWEB)

    Rangel, Elidiane C., E-mail: elidiane@sorocaba.unesp.br [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil); Santos, Nazir M. dos; Bortoleto, Jose Roberto R.; Durrant, Steven F. [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil); Schreiner, Wido H. [Laboratorio de Interfaces e Filmes Finos, Universidade Federal de Parana (UFPR), C.P. 19044, 81531-990, Curitiba, PR (Brazil); Honda, Roberto Y. [Laboratorio de Plasmas, Universidade Estadual Paulista (UNESP), Departamento de Fisica e Quimica, 12516-410, Guaratingueta, SP (Brazil); Cassia C Rangel, Rita de; Cruz, Nilson C. [Laboratorio de Plasmas Tecnologicos, Universidade Estadual Paulista, Campus Experimental de Sorocaba, Av. Tres de Marco, 511 Alto da Boa Vista, 18087-180, Sorocaba, SP (Brazil)

    2011-12-15

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  16. Detector system for the study of low energy heavy ion reactions using kinematic coincidence technique

    Science.gov (United States)

    Jhingan, Akhil; Kalkal, S.; Sugathan, P.; Golda, K. S.; Ahuja, R.; Gehlot, J.; Madhavan, N.; Behera, B. R.; Mandal, S. K.

    2014-05-01

    The characteristics and performance of a new detector system developed for the study of low energy heavy ion binary reactions using the kinematic coincidence technique are presented. The detector system has been developed to carry out experiments such as multi-nucleon transfer reactions using the General Purpose Scattering Chamber (GPSC) facility at IUAC [1,2]. The detector system consists of a pair of two-dimensional position sensitive multi wire proportional counter (MWPC) and a ΔE - E gas ionization chamber. Both MWPC have an active area of 5×5 cm2, and provide position signals in horizontal (X) and vertical (Y) plane, and timing signal for time of flight measurements. The main design feature of MWPC is the reduced wire pitch of 0.025 in. (0.635 mm) in all electrodes, giving uniform field and faster charge collection, and usage of 10 μm diameter in anode frame which gives higher gains. The position resolution of the detectors was determined to be 0.45 mm FWHM and time resolution was estimated to be 400 ps FWHM. The detector could handle heavy ion count rates exceeding 100 kHz without any break down. The timing and position signals of the detectors are used for kinematic coincidence measurements and subsequent extraction of their mass and angular distributions. The ionization chamber has a conventional transverse field geometry with segmented anode providing multiple ΔE signals for nuclear charge (Z) identification. This article describes systematic study of these detectors in terms of efficiency, count rate handling capability, time, position and energy resolution.

  17. Detector system for the study of low energy heavy ion reactions using kinematic coincidence technique

    Energy Technology Data Exchange (ETDEWEB)

    Jhingan, Akhil, E-mail: akhil@iuac.res.in [Inter University Accelerator Centre, P. O. Box 10502, New Delhi 110067 (India); Kalkal, S. [Deptartment of Physics and Astrophysics, Delhi University, Delhi 110007 (India); Sugathan, P.; Golda, K.S.; Ahuja, R.; Gehlot, J.; Madhavan, N. [Inter University Accelerator Centre, P. O. Box 10502, New Delhi 110067 (India); Behera, B.R. [Deptartment of Physics, Panjab University, Chandigarh 160014 (India); Mandal, S.K. [Deptartment of Physics and Astrophysics, Delhi University, Delhi 110007 (India)

    2014-05-01

    The characteristics and performance of a new detector system developed for the study of low energy heavy ion binary reactions using the kinematic coincidence technique are presented. The detector system has been developed to carry out experiments such as multi-nucleon transfer reactions using the General Purpose Scattering Chamber (GPSC) facility at IUAC [1,2]. The detector system consists of a pair of two-dimensional position sensitive multi wire proportional counter (MWPC) and a ΔE−E gas ionization chamber. Both MWPC have an active area of 5×5 cm{sup 2}, and provide position signals in horizontal (X) and vertical (Y) plane, and timing signal for time of flight measurements. The main design feature of MWPC is the reduced wire pitch of 0.025 in. (0.635 mm) in all electrodes, giving uniform field and faster charge collection, and usage of 10μm diameter in anode frame which gives higher gains. The position resolution of the detectors was determined to be 0.45 mm FWHM and time resolution was estimated to be 400 ps FWHM. The detector could handle heavy ion count rates exceeding 100 kHz without any break down. The timing and position signals of the detectors are used for kinematic coincidence measurements and subsequent extraction of their mass and angular distributions. The ionization chamber has a conventional transverse field geometry with segmented anode providing multiple ΔE signals for nuclear charge (Z) identification. This article describes systematic study of these detectors in terms of efficiency, count rate handling capability, time, position and energy resolution.

  18. A highly sensitive CaF{sub 2}:Dy nanophosphor as an efficient low energy ion dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bhadane, Mahesh S.; Hareesh, K.; Dahiwale, S.S.; Sature, K.R. [Microtron Accelerator Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Patil, B.J. [Department of Physics, Abasaheb Garware College, Pune 411004 (India); Asokan, K.; Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Bhoraskar, V.N. [Microtron Accelerator Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Microtron Accelerator Laboratory, Department of Physics, Savitribai Phule Pune University, Pune 411007 (India)

    2016-11-01

    Highlights: • CaF{sub 2}:Dy nanophosphor synthesized by chemical co-precipitation route. • Phosphors are irradiated by H, Ar and N low energy ions at different fluences. • LEBI irradiated phosphors are characterized by XRD, TEM, FTIR and PL spectroscopy. • First time report to LEIB irradiated for thermoluminescence dosimetric applications. - Abstract: Dysprosium doped calcium fluoride (CaF{sub 2}:Dy) powers synthesized by co-precipitation method were irradiated with low energy ion beams (LEIB) viz. 100 keV H, 200 keV Ar and 350 keV N beams at different fluences and demonstrated for low energy ion dosimetric application. X-ray Diffraction and Transmission electron microscopy revealed the formation of highly crystalline cubic structured particles with size ∼45–50 nm. FTIR spectra of the CaF{sub 2}:Dy samples show changes of some bonds such as N–O asymmetric, C–F bonding and C–H aromatic contain stretching mode after LEIB irradiation. The thermoluminescence (TL) glow curve peaks were observed at 207 °C for Ar ion, at 203 °C for H ion and at 216 °C and 270 °C for N ion. It has been found that CaF{sub 2}:Dy nanophosphor shows a linear response with minimum fading for all the ion species. Computerized Glow Curve Deconvolution was performed for TL curve of high fluence ion irradiated nanophosphor to estimate the trapping parameters and the respective figure of merit (FOM) found to be very appropriate for all the nanophosphor. These results indicated that the CaF{sub 2}:Dy can be used as a low energy ion detector or dose.

  19. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar+ Ion Beam Treatment

    Science.gov (United States)

    Hasan, Syed Azkar Ul; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

    2016-01-01

    High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar+ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar+ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar+ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination. PMID:26771616

  20. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar⁺ Ion Beam Treatment.

    Science.gov (United States)

    Azkar Ul Hasan, Syed; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

    2016-01-12

    High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar⁺ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar⁺ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar⁺ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination.

  1. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar+ Ion Beam Treatment

    Directory of Open Access Journals (Sweden)

    Syed Azkar Ul Hasan

    2016-01-01

    Full Text Available High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar+ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar+ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar+ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination.

  2. Silkworm eggs: An ideal model for studying the biological effects of low energy Ar + ion interaction in animals

    Science.gov (United States)

    Ling, Lin; Liu, Xuelan; Xu, Jiaping; You, Zhengying; Zhou, Jingbo

    2011-09-01

    The object of the current work was to study low energy Ar + ion beam interactions with silkworm eggs and thus provide further understanding of the mechanisms involved in ion bombardment-induced direct gene transfer into silkworm eggs. In this paper, using low-energy Ar + ion beam bombardment combined with piggyBac transposon, we developed a novel method to induce gene transfer in silkworm. Using bombardment conditions optimized for egg-incubation (25 keV with ion fluences of 800 × 2.6 × 10 15 ions/cm 2 in dry state under vacuum), vector pBac{3 × P3-EGFPaf} and helper plasmid pHA3pig were successfully transferred into the silkworm eggs. Our results obtained from by PCR assay and genomic Southern blotting analysis of the G1 generations provide evidence that low-energy ion beam can generate some craters that play a role in acting as pathways of exogenous DNA molecules into silkworm eggs.

  3. RAPD and SSR Polymorphisms in Mutant Lines of Transgenic Wheat Mediated by Low Energy Ion Beam

    Science.gov (United States)

    Wang, Tiegu; Huang, Qunce; Feng, Weisen

    2007-10-01

    Two types of markers-random amplified polymorphic DNA (RAPD) and simple sequence repeat DNA (SSR)-have been used to characterize the genetic diversity among nine mutant lines of transgenic wheat intermediated by low energy ion beam and their four receptor cultivars. The objectives of this study were to analyze RAPD-based and SSR-based genetic variance among transgenic wheat lines and with their receptors, and to find specific genetic markers of special traits of transgenic wheat lines. 170 RAPD primers were amplified to 733 fragments in all the experimental materials. There were 121 polymorphic fragments out of the 733 fragments with a ratio of polymorphic fragments of 16.5%. 29 SSR primer pairs were amplified to 83 fragments in all the experiment materials. There were 57 polymorphic fragments out of the 83 fragments with a ratio of polymorphic fragments of 68.7%. The dendrograms were prepared based on a genetic distance matrix using the UPGMA (Unweighted Pair-group Method with Arithmetic averaging) algorithm, which corresponded well to the results of the wheat pedigree analysis and separated the 13 genotypes into four groups. Association analysis between RAPD and SSR markers with the special traits of transgenic wheat mutant lines discovered that three RAPD markers, s1, opt-16, and f14, were significantly associated with the muticate trait, while three SSR markers, Rht8 (Xgwm261), Rht-B1b, and Rht-D1b, highly associated with the dwarf trait. These markers will be useful for marker-assistant breeding and can be used as candidate markers for further gene mapping and cloning.

  4. Tracking of Polycarbonate Films using Low-energy Ions Final Report CRADA No. TC-774-94

    Energy Technology Data Exchange (ETDEWEB)

    Musket, R. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2018-01-24

    Ion tracking is performed almost exclusively using ions with energies near or above the maximum in electronic stopping. For the present study, we have examined the results of etching ion tracks created by ions bombarding polycarbonate films with energies corresponding to stopping well below the maximum and just above the anticipated threshold for creating etchable latent tracks. Low-energy neon and argon ions with 18-60 keV /amu and fluences of about 108/cm2 were used to examine the limits for producing etchable tracks in polycarbonate films. By concentrating on the early stages of etching (i.e., -20 nm < SEM hole diameter < -100 nm), we can directly relate the energy deposition calculated for the incident ion to the creation of etchable tracks. The experimental results will be discussed with regard to the energy losses of the ions in the polycarbonate films and to the formation of continuous latent tracks through the entire thickness the films. These results have significant implications with respect to the threshold for formation of etchable tracks and to the use of low-energy ions for lithographic applications.

  5. Electrostatic interaction between Interball-2 and the ambient plasma. 2. Influence on the low energy ion measurements with Hyperboloid

    Directory of Open Access Journals (Sweden)

    M. Hamelin

    Full Text Available The measurement of the thermal ion distributions in space is always strongly influenced by the ion motion through the complex 3D electrostatic potential structure built around a charged spacecraft. In this work, we study the related aberrations of the ion distribution detected on board, with special application to the case of the Hyperboloid instrument borne by the Interball-2 auroral satellite. Most of the time, the Interball-2 high altitude auroral satellite is charged at some non-negligible positive potential with respect to the ambient plasma, as shown in part 1; in consequence, the measurement of magnetospheric low energy ions (< 80 eV with the Hyperboloid instrument can be disturbed by the complex electric potential environment of the satellite. In the case of positive charging, as in previous experiments, a negative bias is applied to the Hyperboloid structure in order to reduce this effect and to keep as much as possible the opportunity to detect very low energy ions. Then, the ions reaching the Hyperboloid entrance windows would have travelled across a continuous huge electrostatic lens involving various spatial scales from ~ 10 cm (detector radius to ~ 10 m (satellite antennas. Neglecting space charge effects, we have computed the ion trajectories that are able to reach the Hyperboloid windows within their acceptance angles. There are three main results: (i for given values of the satellite potential, and for each direction of arrival (each window, we deduced the related energy cutoff; (ii we found that all ions in the energy channel, including the cutoff, can come from a large range of directions in the unperturbed plasma, especially when the solar panels or antennas act as electrostatic mirrors; (iii for higher energy channels, the disturbances are reduced to small angular shifts. Biasing of the aperture is not very effective with the Hyperboloid instrument (as on previous missions with instruments installed close to the spacecraft

  6. Electrostatic interaction between Interball-2 and the ambient plasma. 2. Influence on the low energy ion measurements with Hyperboloid

    Directory of Open Access Journals (Sweden)

    M. Hamelin

    2002-03-01

    Full Text Available The measurement of the thermal ion distributions in space is always strongly influenced by the ion motion through the complex 3D electrostatic potential structure built around a charged spacecraft. In this work, we study the related aberrations of the ion distribution detected on board, with special application to the case of the Hyperboloid instrument borne by the Interball-2 auroral satellite. Most of the time, the Interball-2 high altitude auroral satellite is charged at some non-negligible positive potential with respect to the ambient plasma, as shown in part 1; in consequence, the measurement of magnetospheric low energy ions (< 80 eV with the Hyperboloid instrument can be disturbed by the complex electric potential environment of the satellite. In the case of positive charging, as in previous experiments, a negative bias is applied to the Hyperboloid structure in order to reduce this effect and to keep as much as possible the opportunity to detect very low energy ions. Then, the ions reaching the Hyperboloid entrance windows would have travelled across a continuous huge electrostatic lens involving various spatial scales from ~ 10 cm (detector radius to ~ 10 m (satellite antennas. Neglecting space charge effects, we have computed the ion trajectories that are able to reach the Hyperboloid windows within their acceptance angles. There are three main results: (i for given values of the satellite potential, and for each direction of arrival (each window, we deduced the related energy cutoff; (ii we found that all ions in the energy channel, including the cutoff, can come from a large range of directions in the unperturbed plasma, especially when the solar panels or antennas act as electrostatic mirrors; (iii for higher energy channels, the disturbances are reduced to small angular shifts. Biasing of the aperture is not very effective with the Hyperboloid instrument (as on previous missions with instruments installed close to the spacecraft

  7. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar+ Ion Beam Treatment

    OpenAIRE

    Syed Azkar Ul Hasan; Youngdo Jung; Seonggi Kim; Cho-Long Jung; Sunjong Oh; Junhee Kim; Hyuneui Lim

    2016-01-01

    High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar+ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surfac...

  8. Modeling Proton- and Light Ion-Induced Reactions at Low Energies in the MARS15 Code

    Energy Technology Data Exchange (ETDEWEB)

    Rakhno, I. L. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Mokhov, N. V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Gudima, K. K. [National Academy of Sciences, Cisineu (Moldova)

    2015-04-25

    An implementation of both ALICE code and TENDL evaluated nuclear data library in order to describe nuclear reactions induced by low-energy projectiles in the Monte Carlo code MARS15 is presented. Comparisons between results of modeling and experimental data on reaction cross sections and secondary particle distributions are shown.

  9. Low energy RBS-channeling measurement system with the use of a time-of-flight scattered ion detector

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Masataka; Kobayashi, Naoto; Hayashi, Nobuyuki [Electrotechnical Lab., Tsukuba, Ibaraki (Japan)

    1996-07-01

    We have developed a low energy Rutherford backscattering spectrometry-ion channeling measurement system for the analysis of thin films and solid surfaces with the use of several tens keV hydrogen ions and a time-of-flight particle energy spectrometer. For the detection of the scattered ions new TOF spectrometer has been developed, which consists of two micro-channel-plate detectors. The pulsing of the primary ion beam is not necessary for this type of TOF measurement, and it is possible to observe continues scattered ion beams. The dimension of whole system is very compact compared to the conventional RBS-channeling measurement system with the use of MeV He ions. The energy resolution, {delta} E/E, for 25 keV H{sup +} was 4.1%, which corresponds to the depth resolution of 4.8 nm for silicon. The depth resolution of our system is better than that of conventional RBS system with MeV helium ions and solid state detectors. We have demonstrated the ion channeling measurement by this system with 25 keV hydrogen ions. The system can be available well to the analysis of thin films and solid surfaces with the use of the ion channeling effect. The observation of the reaction between Fe and hydrogen terminated silicon surface was also demonstrated. (J.P.N.)

  10. Surface studies by low energy ion beams: Cu/Ru(0001) and Cu/O/Ru(0001)

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Y.G.; O`Connor, D.J.; MacDonald, R.J. [Newcastle Univ., NSW (Australia). Dept. of Physics; Wandelt, H. [Institut fur Physikalische und Theoretische Chemie der Universitat Bonn, Bonn (Germany).; Zee, H. van [Eindhoven University of Technology, Eindhoven (Netherlands) Dept. of Physics

    1993-12-31

    The surface structure of Cu on Ru(OOO1) has been studied by low energy Li{sup +} ion scattering. It was found that Cu forms pseudomorphic islands for two layers. The effects of Cu on an O-precovered RU(OOO1) surface has also been investigated using keV He{sup +} ions. The results show that during the deposition of Cu, O is displaced from the Ru surface and migrated onto the top of the surface of the growing overlayer. The floated out O has been tested, showing a disordered overlayer. 5 refs., 3 figs.

  11. Tungsten oxide thin film bombarded with a low energy He ion beam: evidence for a reduced erosion and W enrichment

    Science.gov (United States)

    Martin, C.; Hijazi, H.; Addab, Y.; Domenichini, B.; Bannister, M. E.; Meyer, F. W.; Pardanaud, C.; Giacometti, G.; Cabié, M.; Roubin, P.

    2017-12-01

    Nanocrystalline tungsten oxide (WO3) thin films synthesized by thermal oxidation of tungsten substrates were exposed to low energy helium ions (energy: 80 eV; flux: 1.4-1.7 × 1020 m-2 s-1) at room temperature and at 673 K. The structure and morphology changes of the oxide were studied using Raman spectroscopy and electron microscopy. Due to the low ion energy, no erosion is observed at room temperature. In contrast, at 673 K, a color change is observed and a significant erosion is measured (˜70 nm for a fluence of ˜4 × 1021 m-2) due to a synergetic effect between ion bombardment and heating. We show that erosion processes and structural changes strongly depend on the ion fluence and in particular the higher the fluence, the lower the erosion yield, most likely due to oxygen depletion in the oxide near-surface layers.

  12. An investigation on the ultra-low energy As ion implantation process and the dopant behaviour during thermal processing

    CERN Document Server

    Whelan, S

    2001-01-01

    Characterisation of the ultra-low energy (ULE) As ion implantation profile (dopant and damage distributions) in Si has been achieved using medium energy ion scattering (MEIS) and secondary ion mass spectrometry (SIMS), in conjunction with a sputter profile deconvolution code (IMPETUS). The Si damage re-growth, dopant substitutionality, diffusion and retention processes that occur during thermal annealing have been investigated as a function of the implant damage and anneal gas ambient. It has been shown that for dopant distributions with a range less than 100A, significant error in the SIMS depth scale occurs when assuming a constant erosion rate throughout sputtering. The sputter depth profile deconvolution code IMPETUS has been used to quantify the errors associated with this assumption. Accurate simulation of the ULE As ion implant process in Si incorporating oxide accumulation effects (segregation) and self-sputtering has been obtained and validated with high resolution MEIS measurements. The code calcula...

  13. Hybrid systems with Ag nanocrystals and Si nanostructures synthesized by ultra-low-energy ion beam synthesis

    Science.gov (United States)

    Carrada, M.; Haj Salem, A.; Pecassou, B.; Carles, R.; Ben Assayag, G.

    2017-09-01

    Hybrid systems based on silicon and silver nanocrystals (Si-NCs and Ag-NCs) are of considerable interest in photon conversion solar cells. Due to their plasmonic properties, Ag-NCs strongly increase the photoluminescence emission intensity of Si-NCs located in their vicinity, allowing, in principle, to solve the problem of their low emission yield. In this work, we have elaborated 2D networks of Ag-NCs and amorphous Si nanoparticles in a controlled way by using Ultra-Low-Energy Ion-Beam-Synthesis. In the proposed synthesis scheme, a 2D layer of Si-NCs is first obtained by implanting Si+ ions at ultra low energy (from 1 to 3 keV) in a SiO2 layer with subsequent high temperature thermal annealing. Then, Ag+ ions are implanted in the same matrix at energies between 3 and 10 keV and crystalline Ag-NCs are formed during the implantation step. Several configurations with either 2D arrays or a large band of Ag-NCs have been obtained following the Ag+ implantation energy. Enhancement of the PL emission from Si nanostructures, which is related to the presence of Ag-NCs, has been observed under specific arrangement of the two embedded subsystems. In this type of synthesis, a combination of physical phenomena including ion mixing, implantation damage, point defect, and thermal diffusion has been taken into account in order to explain and thus control the structural and the optical characteristics of the system.

  14. Extraction and low energy beam transport from a surface ion source at the TRIUMF-ISAC facility

    Science.gov (United States)

    Sen, A.; Ames, F.; Bricault, P.; Lassen, J.; Laxdal, A.; Mjos, A.

    2016-06-01

    A large fraction of radioactive beams produced and delivered at TRIUMF's isotope separator and accelerator facility, ISAC, are using either a surface ion source or a resonant ionization laser ion source, which share a common design. To characterize the operation of the ion sources, simulations were performed to determine the ion beam optics and beam envelope properties of the extracted beam. Furthermore ion-optics calculations were performed to determine the transmission parameters through the mass separator magnet. Emittances are measured in the ISAC low energy beam line right after the mass separator. The recent addition of a channeltron to the Allison emittance meter scanner now allows us to measure emittances for ion beams with intensities as low as 105 ions/s. This is particularly useful for establishing high resolution, high throughput mass separator tunes for radioactive isotope beams. This paper discusses emittance measurements of low intensity beams, typical emittance scans for the surface ion source and the resonant laser ionized source for different source parameters. The observed results are compared to the simulations and discussed.

  15. Extraction and low energy beam transport from a surface ion source at the TRIUMF-ISAC facility

    Energy Technology Data Exchange (ETDEWEB)

    Sen, A., E-mail: asen.kvi@gmail.com; Ames, F.; Bricault, P.; Lassen, J.; Laxdal, A.; Mjos, A.

    2016-06-01

    A large fraction of radioactive beams produced and delivered at TRIUMF’s isotope separator and accelerator facility, ISAC, are using either a surface ion source or a resonant ionization laser ion source, which share a common design. To characterize the operation of the ion sources, simulations were performed to determine the ion beam optics and beam envelope properties of the extracted beam. Furthermore ion-optics calculations were performed to determine the transmission parameters through the mass separator magnet. Emittances are measured in the ISAC low energy beam line right after the mass separator. The recent addition of a channeltron to the Allison emittance meter scanner now allows us to measure emittances for ion beams with intensities as low as 10{sup 5} ions/s. This is particularly useful for establishing high resolution, high throughput mass separator tunes for radioactive isotope beams. This paper discusses emittance measurements of low intensity beams, typical emittance scans for the surface ion source and the resonant laser ionized source for different source parameters. The observed results are compared to the simulations and discussed.

  16. Copper gettering at half the projected ion range induced by low-energy channeling He implantation into silicon

    Science.gov (United States)

    Fichtner, P. F. P.; Behar, M.; Kaschny, J. R.; Peeva, A.; Koegler, R.; Skorupa, W.

    2000-08-01

    He+ ions were implanted at 40 keV into Si channel direction at room temperature (RT) and at 350 °C. The Si samples were subsequently doped with Cu in order to study the gettering of Cu atoms at the defective layer. A subsequent annealing at 800 °C was performed in order to anneal the implantation damage and redistribute the Cu into the wafer. The samples were analyzed by Rutherford backscattering channeling and transmission electron microscopy techniques. The Cu distribution was measured by secondary ion mass spectrometry (SIMS). The SIMS experiments show that, while the 350 °C implant induces gettering at the He projected range (Rp) region, the same implant performed at RT has given as a result, gettering at both the Rp and Rp/2 depths. Hence, this work demonstrates that the Rp/2 effect can be induced by a light ion implanted at low energy into channeling direction.

  17. Low-energy ion bombardment to tailor the interfacial and mechanical properties of polycrystalline 3C-silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fang; Li, Carolina H.; Pisano, Albert P.; Carraro, Carlo; Maboudian, Roya [Department of Chemical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 and Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027 (China); Department of Chemical Engineering, University of California, Berkeley, Berkeley, California 94720 (United States); Department of Mechanical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 (United States); Department of Chemical Engineering and Berkeley Sensor and Actuator Center, University of California, Berkeley, Berkeley, California 94720 (United States)

    2010-09-15

    Low-energy Ar{sup +} ion bombardment of polycrystalline 3C-silicon carbide (poly-SiC) films is found to be a promising surface modification method to tailor the mechanical and interfacial properties of poly-SiC. The film average stress decreases as the ion energy and the bombardment time increase. Furthermore, this treatment is found to change the strain gradient of the films from positive to negative values. The observed changes in stress and strain gradient are explained by ion peening and thermal spikes models. In addition, the poly-SiC films show a significant enhancement in corrosion resistance by this treatment, which is attributed to a reduction in surface energy and to an increase in the compressive stress in the near-surface region.

  18. Ion velocities in the presheath of electronegative, radio-frequency plasmas measured by low-energy cutoff

    Energy Technology Data Exchange (ETDEWEB)

    Sobolewski, Mark A.; Wang, Yicheng; Goyette, Amanda [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2016-07-11

    Simple kinematic considerations indicate that, under certain conditions in radio-frequency (rf) plasmas, the amplitude of the low-energy peak in ion energy distributions (IEDs) measured at an electrode depends sensitively on ion velocities upstream, at the presheath/sheath boundary. By measuring this amplitude, the velocities at which ions exit the presheath can be determined and long-standing controversies regarding presheath transport can be resolved. Here, IEDs measured in rf-biased, inductively coupled plasmas in CF{sub 4} gas determined the presheath exit velocities of all significant positive ions: CF{sub 3}{sup +}, CF{sub 2}{sup +}, CF{sup +}, and F{sup +}. At higher bias voltages, we detected essentially the same velocity for all four ions. For all ions, measured velocities were significantly lower than the Bohm velocity and the electropositive ion sound speed. Neither is an accurate boundary condition for rf sheaths in electronegative gases: under certain low-frequency, high-voltage criteria defined here, either yields large errors in predicted IEDs. These results indicate that many widely used sheath models will need to be revised.

  19. Low energy ion-solid interactions and chemistry effects in a series of pyrochlores

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Liyuan [School of Nuclear Science and Technology, Lanzhou University, Lanzhou Gansu China; Li, Yuhong [School of Nuclear Science and Technology, Lanzhou University, Lanzhou Gansu China; Devanathan, Ram [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington; Setyawan, Wahyu [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland Washington; Gao, Fei [Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor Michigan

    2017-04-03

    The effect of chemistry on low energy recoil events was investigated at 10 K for each type of atom in pyrochlores using molecular dynamics simulation. Contour plots of the threshold displacement energy (Ed) in Gd2Zr2O7 have been produced along more than 80 directions for each individual species. The Ed surface for each type of atom in Gd2Zr2O7 is highly anisotropic; Ed of Zr exhibits the largest degree of anisotropy, while that of O8b exhibits the smallest. The recommended values of Ed in Gd2Zr2O7 based on the observed minima are 56, 94 and 25 eV, respectively for Gd, Zr and O. The influence of cation radius on Ed in pyrochlores A2B2O7 (with A-site ranging from Lu3+ to La3+ and B-site ranging from Ti4+ to Ce4+) was also investigated along three directions [100], [110] and [111]. The Ed in pyrochlores strongly depended on the atom type, atom mass, knock-on direction, and lattice position. The defects produced after low energy displacement events included cation antisite defects, cation Frenkel pairs, anion Frenkel pairs, various vacancies and interstitials. Ce doping in pyrochlores may affect the radiation response, because it resulted in drastic changes in cation and anion displacement energies and formation of an unusual type of anti-site defect. This work demonstrates links between Ed and amorphization resistance.

  20. Linear and nonlinear effects at low energy ion bombardment of solid xenon

    DEFF Research Database (Denmark)

    Dutkiewicz, L.; Pedrys, R.; Schou, Jørgen

    1996-01-01

    Elastic sputtering of crystalline xenon by 20-750 eV Xe ions has been studied with molecular dynamics. The nonlinear effects are dominant at 250 eV ion bombardment. They result in a partly amorphization of the impact volume as well as in a considerable reduction of the surface binding energy...

  1. Localized subsurface modification of materials using micro-low-energy multiple ion beamlets

    Directory of Open Access Journals (Sweden)

    Abhishek Chowdhury

    2011-12-01

    Full Text Available Generation of focused multiple ion beamlets from an intense microwave plasma source is investigated for the creation of localized subsurface modification of materials. Unlike conventional single element focused ion beam (FIB systems, the plasma source is capable of providing ion beams of multiple elements. Two types of plasma electrodes (PE are employed, one with a honeycomb structure with notched apertures and another with a 5×5 array of through apertures, both attached to the plasma source and are capable of generating focused ion beamlets (50 - 100 μm diameter in a patterned manner. Measurements of ion saturation current near the PE indicate that the plasma is uniform over an area of ∼ 7 cm2, which is further confirmed by uniformity in extracted beam current through the apertures. The ion beams are applied to investigate change in electrical sheet resistance Rs of metallic thin films in a controlled manner by varying the ionic species and beam energy. Results indicate a remarkable increase in Rs with beam energy (∼ 50 % at 1 keV for Ar ions, and with ionic species (∼ 90% for Krypton ions at 0.6 keV, when 80 nm thick copper films are irradiated by ∼2 cm diameter ion beams. Ion induced surface roughness is considered as the main mechanism for this change as confirmed by atomic force microscopy (AFM measurements. Predictions for micro-beamlet induced change in Rs are discussed. The experimental results are verified using TRIM and AXCEL-INP simulations.

  2. Low energy Ar+ ion irradiation induced surface modification in cadmium zinc telluride (CdZnTe)

    Science.gov (United States)

    Tripathi, J. K.; Harilal, S. S.; Hassanein, A.

    2014-09-01

    In this paper, we report on modifications in structural, stoichiometry, and optical properties of cadmium zinc telluride (CdZnTe) crystals due to 1 keV Ar+ ion irradiation as a function of ion fluence, using ion flux of 1.7 × 1017 ions cm-2 s-1. The CdZnTe crystals were irradiated at normal incidence, using fluence range of 8 × 1017-3 × 1019 ions cm-2. Atomic force microscopy studies show sequential change in surface structure as a function of ion fluence, from homogeneously populated nano-hole to micron sized holes on the entire CZT crystal surface. These holes are well geometrically defined and most of them are rectangular in shape. X-ray photoelectron spectroscopy studies show a reduction in Zn at % while Raman and photoluminescence studies show almost complete depletion of Te inclusions and slight red shifts, respectively, due to ion irradiations. Schottky diode radiation detectors fabricated from such defect free CZT crystals will show significantly higher energy resolution.

  3. Cross section for production of low-energy electron-positron pairs by relativistic heavy ions

    Science.gov (United States)

    Eby, P. B.

    1991-01-01

    Starting with the lowest-order unscreened QED matrix element for electron-positron pair production by heavy charged particles, the paper calculates the cross section for this process differential in all independent variables and valid for all pair energies small compared to the incident particle energy. Integration over the possible emission angles of one of the pair members gives an expression that is valid for low-energy pairs that can be compared with previous work based on the Weizsaecker-Williams method. Integration over the possible angles of the other pair member then yields an expression identical to one derived by Racah. The high energy-transfer limit of the expression for the cross section integrated over electron and positron angles is found to be identical to that of Kelner in the unscreened case.

  4. Measurement of low-energy Na^+ -- Na total collision rate in an ion--neutral hybrid trap

    CERN Document Server

    Goodman, D S; Kwolek, J M; Blümel, R; Narducci, F A; Smith, W W

    2014-01-01

    We present measurements of the total elastic and resonant charge-exchange ion-atom collision rate coefficient $k_\\mathrm{ia}$ of cold sodium (\\ce{Na}) with optically-dark low energy \\ce{Na+} ions in a hybrid ion-neutral trap. To determine $k_\\mathrm{ia}$, we measured the trap loading and loss from both a \\ce{Na} magneto-optical trap (MOT) and a linear radio frequency quadrupole Paul trap. We found the total rate coefficient to be $7.4 \\pm 1.9 \\times 10^{-8}$ cm$^3$/s for the type I \\ce{Na} MOT immersed within an $\\approx 140$ K ion cloud and $1.10 \\pm 0.25 \\times 10^{-7}$ cm$^3$/s for the type II \\ce{Na} MOT within an $\\approx 1070$ K ion cloud. Our measurements show excellent agreement with previously reported theoretical fully quantal \\textit{ab initio} calculations. In the process of determining the total rate coefficient, we demonstrate that a MOT can be used to probe an optically dark ion cloud's spatial distribution within a hybrid trap.

  5. Tailoring molybdenum nanostructure evolution by low-energy He{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, J.K., E-mail: jtripat@purdue.edu; Novakowski, T.J.; Hassanein, A.

    2015-10-30

    Mirror-finished polished molybdenum (Mo) samples were irradiated with 100 eV He{sup +} ions as a function of ion fluence (using a constant flux of 7.2 × 10{sup 20} ions m{sup −2} s{sup −1}) at normal incidence and at 923 K. Mo surface deterioration and nanoscopic fiber-form filament (“Mo fuzz”) growth evolution were monitored by using field emission (FE) scanning electron (SEM) and atomic force (AFM) microscopy studies. Those studies confirm a reasonably clean and flat surface, up to several micrometer scales along with a few mechanical-polishing-induced scratches. However, He{sup +} ion irradiation deteriorates the surface significantly even at 2.1 × 10{sup 23} ions m{sup −2} fluence (about 5 min. irradiation time) and leads to evolution of homogeneously populated ∼75-nm-long Mo nanograins having ∼8 nm intergrain width. The primary stages of Mo fuzz growth, i.e., elongated half-cylindrical ∼70 nm nanoplatelets, and encapsulated bubbles of 20–45 nm in diameter and preferably within the grain boundaries of sub-micron-sized grains, were observed after 1.3 × 10{sup 24} ions m{sup −2} fluence irradiation. Additionally, a sequential enhancement in the sharpness, density, and protrusions of Mo fuzz at the surface with ion fluence was also observed. Fluence- and flux-dependent studies have also been performed at 1223 K target temperature (beyond the temperature window for Mo fuzz formation). At a constant fluence of 2.6 × 10{sup 24} ions m{sup −2}, 7.2 × 10{sup 20} ions m{sup −2} s{sup −1} flux generates a homogeneous layered and stacked nanodiscs of ∼70 nm diameter. On the other hand, 1.2 × 10{sup 21} ions m{sup −2} s{sup −1} flux generates a combination of randomly patched netlike nanomatrix networked structure, mostly with ∼105 nm nanostructure wall width, various-shaped pores, and self-organized nano arrays. While the observed netlike nanomatrix network structures for 8.6 × 10{sup 24} ions m{sup −2} fluence (at a constant

  6. Feasibility of a 90° electric sector energy analyzer for low energy ion beam characterization

    Energy Technology Data Exchange (ETDEWEB)

    Mahinay, C. L. S., E-mail: cmahinay@nip.upd.edu.ph; Ramos, H. J. [National Institute of Physics, University of the Philippines, Diliman, Quezon City 1101, Metro Manila (Philippines); Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

    2015-02-15

    A simple formula to calculate refocusing by locating the output slit at a specific distance away from the exit of 90° ion deflecting electric sector is given. Numerical analysis is also performed to calculate the ion beam trajectories for different values of the initial angular deviation of the beam. To validate the theory, a compact (90 mm × 5.5 mm × 32 mm) 90° sector ESA is fabricated which can fit through the inner diameter of a conflat 70 vacuum flange. Experimental results show that the dependence of resolution upon the distance between the sector exit and the Faraday cup agrees with the theory. The fabricated 90° sector electrostatic energy analyzer was then used to measure the space resolved ion energy distribution functions of an ion beam with the energy as low as 600 eV.

  7. Ion beams in SEM : An experiment towards a high brightness low energy spread electron impact gas ion source

    NARCIS (Netherlands)

    Jun, D.S.; Kutchoukov, V.G.; Kruit, P.

    2011-01-01

    A next generation ion source suitable for both high resolution focused ion beam milling and imaging applications is currently being developed. The new ion source relies on a method of which positively charged ions are extracted from a miniaturized gas chamber where neutral gas atoms become ionized

  8. Interaction of low-energy highly charged ions with matter; Wechselwirkung niederenergetischer hochgeladener Ionen mit Materie

    Energy Technology Data Exchange (ETDEWEB)

    Ginzel, Rainer

    2010-06-09

    The thesis presented herein deals with experimental studies of the interaction between highly charged ions and neutral matter at low collision energies. The energy range investigated is of great interest for the understanding of both charge exchange reactions between ions comprising the solar wind and various astrophysical gases, as well as the creation of near-surface nanostructures. Over the course of this thesis an experimental setup was constructed, capable of reducing the kinetic energy of incoming ions by two orders of magnitude and finally focussing the decelerated ion beam onto a solid or gaseous target. A coincidence method was employed for the simultaneous detection of photons emitted during the charge exchange process together with the corresponding projectile ions. In this manner, it was possible to separate reaction channels, whose superposition presumably propagated large uncertainties and systematic errors in previous measurements. This work has unveiled unexpectedly strong contributions of slow radiative decay channels and clear evidence of previously only postulated decay processes in charge exchange-induced X-ray spectra. (orig.)

  9. Optimization of a Short Faraday Cup for Low-Energy Ions using Numerical Simulations

    CERN Document Server

    Bravin, E; Garcia Sosa, A; Welsch, CP

    2014-01-01

    ISOLDE, the heavy-ion facility at CERN is undergoing a major upgrade with the installation of a superconducting LINAC that will allow post-acceleration of ion beams up to 10 MeV/u. In this framework, customized beam diagnostics are being developed in order to fulfill the design requirements as well as to fit in the compact diagnostic boxes foreseen. The main detector of this system is a compact Faraday cup that will measure beam intensities in the range of 1 pA to 1 nA. In this contribution, simulation results of electrostatic fields and particle tracking are detailed for different Faraday cup prototypes taking into account the energy spectrum and angle of emission of the ion-induced secondary electrons.

  10. Low-energy measurements of electron capture by multicharged ions from excited hydrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Havener, C.C. (Oak Ridge National Laboratory, Oak Ridge, Tennesse 37831-6372 (United States)); Haque, M.A. (Alcorn State University, Lorman, Mississippi 39096 (United States)); Smith, A.C.H. (University College London, WC1E 6BT (United Kingdom)); Urbain, X. (Universite Catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium)); Zeijlmans van Emmichoven, P.A. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6372 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831-6374 (United States))

    1993-06-05

    For very low collision energies electron capture from excited hydrogen by multicharged ions is characterized by enormous cross sections, the predicted maximum being comparable to the geometric size of the Rydberg atom. The ion-atom merged-beams technique is being used to study these collisions for the variety of charge states and the wide range of energies (0.1 to 1000 eV/amu) accessible to the apparatus. A neutral D beam containing a Rydberg atom population proportional to 1/n[sup 3] is produced by collisional electron detachment of 8 keV D[sup [minus

  11. Comparison of Simulation Codes for the Beam Dynamics of Low-Energy Ions

    CERN Document Server

    Hanke, K; Probert, G; Scrivens, R

    2001-01-01

    Results are presented of the simulation of low–energy ion dynamics with three different codes: KOBRA, IGUN and CPO. To share work between different codes one needs to be confident that they agree. For test cases, good agreement was found between the codes and analytical solutions. Where possible, results have been compared to experimental data from the CERN Laser Ion Source. These simulations are in general agreement with the data of the real beam line. c The following article has been submitted to Review of Scientific Instruments. After it is published, it will be found at http://ojps.aip.org/rsio/.

  12. Experimental Studies of Light-Ion Nuclear Reactions Using Low-Energy RI Beams

    Science.gov (United States)

    Yamaguchi, H.; Kahl, D.; Hayakawa, S.; Sakaguchi, Y.; Abe, K.; Shimuzu, H.; Wakabayashi, Y.; Hashimoto, T.; Cherubini, S.; Gulino, M.; Spitaleri, C.; Rapisarda, G. G.; La Cognata, M.; Lamia, L.; Romano, S.; Kubono, S.; Iwasa, N.; Teranishi, T.; Kawabata, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. N.; Kato, S.; Komatsubara, T.; Coc, A.; de Sereville, N.; Hammache, F.; Kiss, G.; Bishop, S.

    CRIB (CNS Radio-Isotope Beam separator) is a low-energy RI beam separator of Center for Nuclear Study (CNS), the University of Tokyo. Studies on nuclear astrophysics, nuclear structure, and other interests have been performed using the RI beams at CRIB, forming international collaborations. A striking method to study astrophyiscal reactions involving radioactive nuclei is the thick-target method in inverse kinematics. Several astrophysical alpha-induced reactions have been be studied with that method at CRIB. A recent example is on the α resonant scattering with a radioactive 7Be beam. This study is related to the astrophysical 7Be(α , γ ) reactions, important at hot p-p chain and ν p-process in supernovae. There have been measurements based on several indirect methods, such as the asymptotic normalization coefficient (ANC) and Trojan horse method (THM). The first THM measurement using an RI beam has been performed at CRIB, to study the 18F(p, α )15O reaction at astrophysical energies via the three body reaction 2H(18F, α 15O)n. The 18F(p, α )15O reaction rate is crucial to understand the 511-keV γ -ray production in nova explosion phenomena, and we successfully evaluated the reaction cross section at novae temperature and below experimentally for the first time.

  13. Unusual features of proton and α-spectra from low-energy heavy-ion ...

    Indian Academy of Sciences (India)

    be expanded with radioactive ion beams. In the case of α-spectra, measurements should be made with 16O and other projectiles covering a wide angular range to shed more light on the possible non-statistical reaction mechanisms. Acknowledgements. The work described in this paper is a team work with the colleagues A ...

  14. OPENMED: A facility for biomedical experiments based on the CERN Low Energy Ion Ring (LEIR)

    Science.gov (United States)

    Carli, Christian

    At present protons and carbon ions are in clinical use for hadron therapy at a growing number of treatment centers all over the world. Nevertheless, only limited direct clinical evidence of their superiority over other forms of radiotherapy is available [1]. Furthermore fundamental studies on biological effects of hadron beams have been carried out at different times (some a long time ago) in different laboratories and under different conditions. Despite an increased availability of ion beams for hadron therapy, beam time for preclinical studies is expected to remain insufficient as the priority for therapy centers is to treat the maximum number of patients. Most of the remaining beam time is expected to be required for setting up and measurements to guarantee appropriate good quality beams for treatments. The proposed facility for biomedical research [2] in support of hadron therapy centers would provide ion beams for interested research groups and allow them to carry out basic studies under well defined conditions. Typical studies would include radiobiological phenomena like relative biological effectiveness with different energies, ion species, and intensities. Furthermore possible studies include the development of advanced dosimetry in heterogeneous materials that resemble the human body, imaging techniques and, at a later stage, when the maximum energy with the LEIR magnets can be reached, fragmentation.

  15. Biological effects of low energy nitrogen ion implantation on Jatropha curcas L. seed germination

    Science.gov (United States)

    Xu, Gang; Wang, Xiao-teng; Gan, Cai-ling; Fang, Yan-qiong; Zhang, Meng

    2012-09-01

    To explore the biological effects of nitrogen ion beam implantation on dry Jatropha curcas seed, a beam of N+ with energy of 25 keV was applied to treat the dry seed at six different doses. N+ beam implantation greatly decreased germination rate and seedling survival rate. The doses within the range of 12 × 1016 to 15 × 1016 ions cm-2 severely damaged the seeds: total antioxidant capacity (TAC), germination rate, seedling survival rate, reduced ascorbate acid (HAsA) and reduced glutathione (GSH) contents, and most of the tested antioxidases activity (i.e. catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD)) reached their lowest levels. At a dose of 18 × 1016 ion cm-2, biological repair took place: moderate increases were found in TAC, germination rate, seedling survival rate, HAsA and GSH contents, and some antioxidant enzyme activities (i.e. CAT, APX, SOD and GPX). The dose of 18 × 1016 ions cm-2 may be the optimum dose for use in dry J. curcas seed mutation breeding. CAT, HAsA and GSH contributed to the increase of TAC, but CAT was the most important. POD performed its important role as seed was severely damaged. The main role of the HAsA-GSH cycle appeared to be for regeneration of HAsA.

  16. Low flux and low energy helium ion implantation into tungsten using a dedicated plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Pentecoste, Lucile [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Thomann, Anne-Lise, E-mail: anne-lise.thomann@univ-orleans.fr [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Melhem, Amer; Caillard, Amael; Cuynet, Stéphane; Lecas, Thomas; Brault, Pascal [GREMI, CNRS/Université d’Orléans, 14 rue d’Issoudun, B.P. 6744, 45067 Orléans Cedex2 (France); Desgardin, Pierre; Barthe, Marie-France [CNRS, UPR3079 CEMHTI, 1D avenue de la Recherche Scientifique, 45071 Orléans Cedex2 (France)

    2016-09-15

    The aim of this work is to investigate the first stages of defect formation in tungsten (W) due to the accumulation of helium (He) atoms inside the crystal lattice. To reach the required implantation conditions, i.e. low He ion fluxes (10{sup 11}–10{sup 14} ions.cm{sup 2}.s{sup −1}) and kinetic energies below the W atom displacement threshold (about 500 eV for He{sup +}), an ICP source has been designed and connected to a diffusion chamber. Implantation conditions have been characterized by means of complementary diagnostics modified for measurements in this very low density helium plasma. It was shown that lowest ion fluxes could only be reached for the discharge working in capacitive mode either in α or γ regime. Special attention was paid to control the energy gained by the ions by acceleration through the sheath at the direct current biased substrate. At very low helium pressure, in α regime, a broad ion energy distribution function was evidenced, whereas a peak centered on the potential difference between the plasma and the biased substrate was found at higher pressures in the γ mode. Polycrystalline tungsten samples were exposed to the helium plasma in both regimes of the discharge and characterized by positron annihilation spectroscopy in order to detect the formed vacancy defects. It was found that W vacancies are able to be formed just by helium accumulation and that the same final implanted state is reached, whatever the operating mode of the capacitive discharge.

  17. Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing

    NARCIS (Netherlands)

    Dobrovolskiy, S.; Yakshin, A.E.; Yakshin, Andrey; Tichelaar, F.D.; Verhoeven, J.; Louis, E.; Louis, Eric; Bijkerk, Frederik

    2010-01-01

    Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10–20 nm were produced by sequential deposition of Si and implantation of 1 keV View the MathML source ions. Only about 3% of the implanted carbon was transferred into the SiC, with a thin, 0.5–1 nm, buried SiC layer being

  18. Low energy ion induced desorption on technical surfaces at room temperature

    CERN Document Server

    Hulla, Georg

    2009-01-01

    The ion-induced pressure instability is a hard limitation for the maximum intensity, and hence the ultimate luminosity achievable in a proton accelerator. This instability is due to the interaction of high intensity proton beams with the residual gas generating positive ions. These ions, accelerated by the beam space charge, impact on the vaccuum chamber wall and lead to the desorption of gaseous species like $H_{2}, CH_{4}, C_{2}H_{4}, C_{2}H_{6}, CO$ and $CO_{2}$. These gases can in turn be ionized by the circulating beam, and initiate a pressure run-away process causing the loss of the stored beam. This phenomenon was first registered right at the beginning of operation of the Intersecting Storage Rings (ISR) at CERN in 1970. Later on, a long term evolution of the pressure was recorded for a stable stored beam current where a change of the residual gas composition was measured. In order to adapt the pumping speed and the surface treatments to the desired circulating beam currents, mathematical tools (e.g. ...

  19. Biological effects of low energy nitrogen ion implantation on Jatropha curcas L. seed germination

    Energy Technology Data Exchange (ETDEWEB)

    Xu Gang, E-mail: xg335300@yahoo.com.cn [Center for Research and Development of Fine Chemicals, Guizhou University, Guiyang 550025 (China); Institute of Entomology, Guizhou University, Guiyang 550025 (China); Wang Xiaoteng [Department of Agricultural Resources and Environment, College of Agricultural, Guizhou University, Guiyang 550025 (China); Gan Cailing; Fang Yanqiong; Zhang Meng [College of Life Sciences, Guizhou University, Guiyang 550025 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We analyzed biological effects of N{sup +} implantation on dry Jatropha curcas seed. Black-Right-Pointing-Pointer N{sup +} implantation greatly decreased seedling survival rate. Black-Right-Pointing-Pointer At doses beyond 15 Multiplication-Sign 10{sup 16} ion cm{sup -2}, biological repair took place. Black-Right-Pointing-Pointer CAT was essential for H{sub 2}O{sub 2} removal. POD mainly functioned as seed was severely hurt. Black-Right-Pointing-Pointer HAsA-GSH cycle mainly contributed to the regeneration of HAsA. - Abstract: To explore the biological effects of nitrogen ion beam implantation on dry Jatropha curcas seed, a beam of N{sup +} with energy of 25 keV was applied to treat the dry seed at six different doses. N{sup +} beam implantation greatly decreased germination rate and seedling survival rate. The doses within the range of 12 Multiplication-Sign 10{sup 16} to 15 Multiplication-Sign 10{sup 16} ions cm{sup -2} severely damaged the seeds: total antioxidant capacity (TAC), germination rate, seedling survival rate, reduced ascorbate acid (HAsA) and reduced glutathione (GSH) contents, and most of the tested antioxidases activity (i.e. catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD)) reached their lowest levels. At a dose of 18 Multiplication-Sign 10{sup 16} ion cm{sup -2}, biological repair took place: moderate increases were found in TAC, germination rate, seedling survival rate, HAsA and GSH contents, and some antioxidant enzyme activities (i.e. CAT, APX, SOD and GPX). The dose of 18 Multiplication-Sign 10{sup 16} ions cm{sup -2} may be the optimum dose for use in dry J. curcas seed mutation breeding. CAT, HAsA and GSH contributed to the increase of TAC, but CAT was the most important. POD performed its important role as seed was severely damaged. The main role of the HAsA-GSH cycle appeared to be for regeneration of HAsA.

  20. Ion beam smoothing with low-energy argon ions and reduction of Néel “orange peel” coupling in magnetic tunnel junctions

    Science.gov (United States)

    Beck, P. A.; Roos, B. F. P.; Demokritov, S. O.; Hillebrands, B.

    2005-04-01

    The influence of low-energy argon bombardment with an ion energy of 30-70 eV and normal incidence on the morphology of a 15-nm-thick Ni 81Fe 19 film on SiO 2 has been studied at room temperature. Scanning tunneling microscope measurements show a reduction of the root-mean-square roughness of over 40%. For magnetic tunnel junctions prepared by involving ion-beam smoothing process, the Néel coupling is substantially reduced and measured by magneto-optic Kerr magnetometry.

  1. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Borodi, Gheorghe

    2008-12-09

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO{sub 2}{sup +} with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H{sub 2} densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH{sup +}, CH{sub 2}{sup +}, and CH{sub 4}{sup +} have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  2. Study of beryllium redeposition under bombardment by high intensity -low energy- hydrogen ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Gureev, V.M.; Guseva, M.I.; Danelyan, L.S. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)] [and others

    1998-01-01

    The results of studying the erosion of beryllium under an effect of intense ion fluxes with the energy of 250 eV, at the fluences {approx}10{sup 2}1 cm{sup -2}, at the MAGRAS-stand are given. The operating conditions under which a practically-complete redeposition of the sputtered beryllium upon the target surface were experimentally-realized. A change in the microstructure of a beryllium target under sputtering and redeposition is analyzed. Some technological applications are considered. (author)

  3. Experiments with low energy ion beam transport into toroidal magnetic fields

    OpenAIRE

    Joshi, N; Droba, M.; Meusel, O.; Ratzinger, U

    2016-01-01

    The stellarator-type storage ring for accumulation of multi- Ampere proton and ion beams with energies in the range of $100~AkeV$ to $1~AMeV$ is designed at Frankfurt university. The main idea for beam confinement with high transversal momentum acceptance was presented in EPAC2006. This ring is typically suited for experiments in plasma physics and nuclear astrophysics. The accumulator ring with a closed longitudinal magnetic field is foreseen with a strength up to $6-8~T$. The experiments wi...

  4. Development of detection systems for low-energy heavy ions at DRAGON

    CERN Document Server

    Engel, S; Chen, A; Dale, C; D'Auria, J M; Giesen, U; Greife, U; Henderson, R; Hunter, D; Hutcheon, D; Openshaw, R; Rogers, J; Rolfs, C; Shotter, A

    2002-01-01

    The new DRAGON facility at TRIUMF is designed to measure alpha and proton capture reactions with radioactive ion beams in inverse kinematics. For nucleo-synthesis in astrophysical scenarios, the relevant energies lie in the 0.15-1 MeV/u range, where very low cross sections are expected. Therefore the separation of the recoil products from the beam particles will be a difficult task. This paper focuses on the end detectors, which will be used to distinguish recoils from beam particles at the end of the DRAGON separator.

  5. Oxygen adsorption on Cu(111) using low energy ion scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.M.; Yao, J.; Shen, Y.G.; King, B.V.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    The surface structure and oxygen adsorption of Cu(l 11) have been studied by 2 keV Li{sup +}, He{sup +} and Ar{sup +} ion scattering . Incident and azimuthal dependences were measured for the clean and O-covered surfaces, and the surface geometry was analysed on the basis of the shadowing features. Experimental results under different oxygen exposures at room temperature showed that the Cu(l 11) surface undergoes a roughening transition and results in a reconstruction where Cu atoms are vertically displaced by about 0.23 Angstroms. 4 refs., 4 figs.

  6. Low-energy collisions of helium clusters with size-selected cobalt cluster ions

    Science.gov (United States)

    Odaka, Hideho; Ichihashi, Masahiko

    2017-04-01

    Collisions of helium clusters with size-selected cobalt cluster ions, Com+ (m ≤ 5), were studied experimentally by using a merging beam technique. The product ions, Com+Hen (cluster complexes), were mass-analyzed, and this result indicates that more than 20 helium atoms can be attached onto Com+ at the relative velocities of 103 m/s. The measured size distributions of the cluster complexes indicate that there are relatively stable complexes: Co2+Hen (n = 2, 4, 6, and 12), Co3+Hen (n = 3, 6), Co4+He4, and Co5+Hen (n = 3, 6, 8, and 10). These stabilities are explained in terms of their geometric structures. The yields of the cluster complexes were also measured as a function of the relative velocity (1 × 102-4 × 103 m/s), and this result demonstrates that the main interaction in the collision process changes with the increase of the collision energy from the electrostatic interaction, which includes the induced deformation of HeN, to the hard-sphere interaction. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80015-0

  7. Irradiation effect on PET surface using low energy argon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, Barakat A. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy, P.O. Box 13759, Inchas, Atomic Energy (Egypt); Abdelrahman, Moustafa M., E-mail: moustafa82003@yahoo.com [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy, P.O. Box 13759, Inchas, Atomic Energy (Egypt); Abdelsalam, Fatama W. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy, P.O. Box 13759, Inchas, Atomic Energy (Egypt); Aly, Kamal A. [Accelerators and Ion Sources Department, Nuclear Research Center, Atomic Energy, P.O. Box 13759, Inchas, Atomic Energy (Egypt); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Physics Department, Faculty of Science and Arts, Khulais, King Abdulaziz University (KAU) (Saudi Arabia)

    2013-01-15

    A study of various physical properties of a PET film irradiated with an Ar beam is reported. SEM images and UV-VIS and FTIR spectra were obtained for a number of ionic fluxes and three irradiation times. Small changes in the energy gap of degradated samples were found, and the SEM images indicate that the optimum homogeneity and roughness are reached after 30 min of irradiation. These results may well be of practical interest. A modified saddle field ion source was used as a preparation tool of the surface of polyethylene terephthalate PET polymer substrate to be ready for coating or thin film deposition. Argon ion beam was used for this purpose, where the scanning electron microscope (SEM) shows that, the best sample is the one which was irradiated to 30 min, where this sample is more homogenous and roughness than other irradiated samples. Also the (UV-VIS) spectrum tells us that, there is small change on energy gap and this is meaning that, the change on electric properties is small also. In this case the sample is more homogenous and of higher roughness than other irradiated samples.

  8. On the origin of apparent Z{sub 1}-oscillations in low-energy heavy-ion ranges

    Energy Technology Data Exchange (ETDEWEB)

    Wittmaack, Klaus, E-mail: wittmaack@helmholtz-muenchen.de

    2016-12-01

    It has been known for quite some time that projected ranges measured by Rutherford backscattering spectrometry for a variety of low-energy heavy ions (energy-to-mass ratio E/M{sub 1} less than ∼0.4 keV/u) exhibit significant or even pronounced deviations from the theoretically predicted smooth dependence on the projectile’s atomic number Z{sub 1}. Studied most thoroughly for silicon targets, the effect was attributed to ‘Z{sub 1} oscillations’ in nuclear stopping, in false analogy to the well established Z{sub 1} oscillations in electronic stopping of low-velocity light ions. In this study an attempt was made to get order into range data published by four different groups. To achieve the goal, the absolute values of the ranges from each group had to be (re-)adjusted by up to about ±10%. Adequate justification for this approach is provided. With the changes made, similarities and differences between the different sets of data became much more transparent than before. Very important is the finding that the distortions in heavy-ion ranges are not oscillatory in nature but mostly one-sided, reflecting element-specific transport of implanted atoms deeper into the solid. Exceptions are rare gas and alkali elements, known to exhibit bombardment induced transport towards the surface. Range distortions reported for Xe and Cs could be reproduced on the basis of the recently established rapid relocation model. The extent of transport into the bulk, observed with many other elements, notably noble metals and lanthanides, reflects their high mobility under ion bombardment. The complexity of the element specific transport phenomena became fully evident by also examining the limited number of data available for the apparent range straggling. Profile broadening was identified in several cases. One element (Eu) was found to exhibit profile narrowing. This observation suggests that implanted atoms may agglomerate at peak concentrations up to 2%, possibly a tool for

  9. Enhanced sputtering yields of carbon due to accumulation of low-energy Xe ions

    Science.gov (United States)

    Kenmotsu, T.; Wada, M.; Hyakutake, T.; Muramoto, T.; Nishida, M.

    2009-05-01

    We have calculated the sputtering yields of carbon and molybdenum under xenon ion bombardment by a Monte Carlo code ACAT which simulates binary collision events in solids. The yields of carbon calculated with ACAT differ from the experimental data below the threshold energy predicted from the semi-empirical formula proposed by Yamamura and Tawara. Meanwhile, the results of ACAT with 14% xenon atoms retained in graphite are in good agreement with the experimental data and the xenon retention in carbon plays an important role in reducing the threshold energy for carbon sputtering. In order to estimate the experimental sputtering yields of carbon, a simplified formula is proposed in the frame of the semi-empirical formula. The formula predicts the yield curve close to the reported sputtering yields of carbon for the condition that carbon target retains 14% xenon atoms.

  10. Interatomic Coulombic Decay as a New Source of Low Energy Electrons in slow Ion-Dimer Collisions

    CERN Document Server

    Iskandar, W; Leredde, A; Flechard, X; Gervais, B; Guillous, S; Hennecart, D; Mery, A; Rangama, J; Zhou, C L; Shiromaru, H; Cassimi, A

    2014-01-01

    We provide the experimental evidence that the single electron capture process in slow collisions between O$^{3+}$ ions and neon dimer targets leads to an unexpected production of low-energy electrons. This production results from the interatomic Coulombic decay process, subsequent to inner shell single electron capture from one site of the neon dimer. Although pure one-electron capture from inner shell is expected to be negligible in the low collision energy regime investigated here, the electron production due to this process overtakes by one order of magnitude the emission of Auger electrons by the scattered projectiles after double-electron capture. This feature is specific to low charge states of the projectile: similar studies with Xe$^{20+}$ and Ar$^{9+}$ projectiles show no evidence of inner shell single-electron capture. The dependence of the process on the projectile charge state is interpreted using simple calculations based on the classical over the barrier model.

  11. A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

    Science.gov (United States)

    Ke, Zhigang; Huang, Qing; Dang, Bingrong; Lu, Yilin; Yuan, Hang; Zhang, Shuqing; Yu, Zengliang

    2010-09-01

    The radiolysis of cysteine under plasma discharge and irradiation of low-energy ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR. In addition, the generation of hydrogen sulfide was also identified. The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (-SH, -NH 3, -COO -) of cysteine, and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified. These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation.

  12. A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

    Energy Technology Data Exchange (ETDEWEB)

    Ke Zhigang [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Huang Qing, E-mail: huangq@ipp.ac.c [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Dang Bingrong [Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); Lu Yilin [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Department of Physics, Anhui University, Hefei 230031 (China); Yuan Hang; Zhang Shuqing; Yu Zengliang [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China)

    2010-09-15

    The radiolysis of cysteine under plasma discharge and irradiation of low-energy ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR. In addition, the generation of hydrogen sulfide was also identified. The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (-SH, -NH{sub 3}, -COO{sup -}) of cysteine, and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified. These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation.

  13. Biaxial texturing of inorganic photovoltaic thin films using low energy ion beam irradiation during growth

    Energy Technology Data Exchange (ETDEWEB)

    Groves, James R [Los Alamos National Laboratory; De Paula, Raymond F [Los Alamos National Laboratory; Hayes, Garrett H [STANFORD UNIV.; Li, Joel B [STANFORD UNIV.; Hammond, Robert H [STANFORD UNIV.; Salleo, Alberto [STANFORD UNIV.; Clemens, Bruce M [STANFORD UNIV.

    2010-05-07

    We describe our efforts to control the grain boundary alignment in polycrystalline thin films of silicon by using a biaxially textured template layer of CaF{sub 2} for photovoltaic device applications. We have chosen CaF{sub 2} as a candidate material due to its close lattice match with silicon and its suitability as an ion beam assisted deposition (mAD) material. We show that the CaF{sub 2} aligns biaxially at a thickness of {approx}10 nm and, with the addition of an epitaxial CaF{sub 2} layer, has an in-plane texture of {approx}15{sup o}. Deposition of a subsequent layer of Si aligns on the template layer with an in-plane texture of 10.8{sup o}. The additional improvement of in-plane texture is similar to the behavior observed in more fully characterized IBAD materials systems. A germanium buffer layer is used to assist in the epitaxial deposition of Si on CaF{sub 2} template layers and single crystal substrates. These experiments confirm that an mAD template can be used to biaxially orient polycrystalline Si.

  14. The effect of low energy helium ion irradiation on tungsten-tantalum (W-Ta) alloys under fusion relevant conditions

    Science.gov (United States)

    Gonderman, S.; Tripathi, J. K.; Novakowski, T. J.; Sizyuk, T.; Hassanein, A.

    2017-08-01

    Currently, tungsten remains the best candidate for plasma-facing components (PFCs) for future fusion devices because of its high melting point, low erosion, and strong mechanical properties. However, continued investigation has shown tungsten to undergo severe morphology changes under fusion-like conditions. These results motivate the study of innovative PFC materials which are resistant to surface morphology evolution. The goal of this work is to examine tungsten-tantalum (W-Ta) alloys, a potential PFC material, and their response to low energy helium ion irradiation. Specifically, W-Ta samples are exposed to 100 eV helium irradiations with a flux of 1.15 × 1021 ions m-2 s-1, at 873 K, 1023 K, and 1173 K for 1 h duration. Scanning electron microscopy (SEM) reveals significant changes in surface deterioration due to helium ion irradiation as a function of both temperature and tantalum concentration in W-Ta samples. X-Ray Diffraction (XRD) studies show a slight lattice parameter expansion in W-Ta alloy samples compared to pure W samples. The observed lattice parameter expansion in W-Ta alloy samples (proportional to increasing Ta wt.% concentrations) reflect significant differences observed in the evolution of surface morphology, i.e., fuzz development processes for both increasing Ta wt.% concentration and target temperature. These results suggest a correlation between the observed morphology differences and the induced crystal structure change caused by the presence of tantalum. Shifts in the XRD peaks before and after 100 eV helium irradiation with a flux of 1.15 × 1021 ions m-2 s-1, 1023 K, for 1 h showed a significant difference in the magnitude of the shift. This has suggested a possible link between the atomic spacing of the material and the accumulated damage. Ongoing research is needed on W-Ta alloys and other innovative materials for their application as irradiation resistant materials in future fusion or irradiation environments.

  15. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Nagatomo, T., E-mail: nagatomo@riken.jp; Kase, M.; Kamigaito, O.; Nakagawa, T. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Tzoganis, V. [Nishina Center for Accelerator Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Cockcroft Institute, Daresbury, Warrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool, Merseyside L69 3BX (United Kingdom)

    2016-02-15

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO{sub 2} (quartz), KBr, Eu-doped CaF{sub 2}, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy {sup 12}C{sup 4+}, {sup 16}O{sup 4+}, and {sup 40}Ar{sup 11+} ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  16. Development of a pepper-pot emittance meter for diagnostics of low-energy multiply charged heavy ion beams extracted from an ECR ion source

    Science.gov (United States)

    Nagatomo, T.; Tzoganis, V.; Kase, M.; Kamigaito, O.; Nakagawa, T.

    2016-02-01

    Several fluorescent materials were tested for use in the imaging screen of a pepper-pot emittance meter that is suitable for investigating the beam dynamics of multiply charged heavy ions extracted from an ECR ion source. SiO2 (quartz), KBr, Eu-doped CaF2, and Tl-doped CsI crystals were first irradiated with 6.52-keV protons to determine the effects of radiation damage on their fluorescence emission properties. For such a low-energy proton beam, only the quartz was found to be a suitable fluorescent material, since the other materials suffered a decay in fluorescence intensity with irradiation time. Subsequently, quartz was irradiated with heavy 12C4+, 16O4+, and 40Ar11+ ions, but it was found that the fluorescence intensity decreased too rapidly to measure the emittance of these heavy-ion beams. These results suggest that a different energy loss mechanism occurs for heavier ions and for protons.

  17. High-Temperature Annealing Induced He Bubble Evolution in Low Energy He Ion Implanted 6H-SiC

    Science.gov (United States)

    Liu, Yu-Zhu; Li, Bing-Sheng; Zhang, Li

    2017-05-01

    Bubble evolution in low energy and high dose He-implanted 6H-SiC upon thermal annealing is studied. The -oriented 6H-SiC wafers are implanted with 15 keV helium ions at a dose of 1 × 10 17 cm -2 at room temperature. The samples with post-implantation are annealed at temperatures of 1073, 1173, 1273, and 1473 K for 30 min. He bubbles in the wafers are examined via cross-sectional transmission electron microscopy (XTEM) analysis. The results present that nanoscale bubbles are almost homogeneously distributed in the damaged layer of the as-implanted sample, and no significant change is observed in the He-implanted sample after 1073 K annealing. Upon 1193 K annealing, almost full recrystallization of He-implantation-induced amorphization in 6H-SiC is observed. In addition, the diameters of He bubbles increase obviously. With continually increasing temperatures to 1273 K and 1473 K, the diameters of He bubbles increase and the number density of lattice defects decreases. The growth of He bubbles after high temperature annealing abides by the Ostwald ripening mechanism. The mean diameter of He bubbles located at depths of 120-135 nm as a function of annealing temperature is fitted in terms of a thermal activated process which yields an activation energy of 1.914+0.236 eV. Supported by the National Natural Science Foundation of China under Grant No 11475229.

  18. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform.

    Science.gov (United States)

    Sun, Gongchen; Senapati, Satyajyoti; Chang, Hsueh-Chia

    2016-04-07

    A microfluidic ion exchange membrane hybrid chip is fabricated using polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (>100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems.

  19. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform†

    Science.gov (United States)

    Sun, Gongchen; Senapati, Satyajyoti

    2016-01-01

    A microfluidic-ion exchange membrane hybrid chip is fabricated by polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (> 100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems. PMID:26960551

  20. A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar⁺ Ion Beam Treatment

    National Research Council Canada - National Science Library

    Azkar Ul Hasan, Syed; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

    2016-01-01

    .... This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar...

  1. A comparative study on low-energy ion beam and neutralized beam modifications of naked DNA and biological effect on mutation

    Science.gov (United States)

    Sarapirom, S.; Thongkumkoon, P.; Prakrajang, K.; Anuntalabhochai, S.; Yu, L. D.

    2012-02-01

    DNA conformation change or damage induced by low-energy ion irradiation has been of great interest owing to research developments in ion beam biotechnology and ion beam application in biomedicine. Mechanisms involved in the induction of DNA damage may account for effect from implanting ion charge. In order to check this effect, we used both ion beam and neutralized beam at keV energy to bombard naked DNA. Argon or nitrogen ion beam was generated and extracted from a radiofrequency (RF) ion source and neutralized by microwave-driven plasma in the beam path. Plasmid DNA pGFP samples were irradiated with the ion or neutralized beam in vacuum, followed by gel electrophoresis to observe changes in the DNA conformations. It was revealed that the ion charge played a certain role in inducing DNA conformation change. The subsequent DNA transfer into bacteria Escherichia coli ( E. coli) for mutation analysis indicated that the charged ion beam induced DNA change had high potential in mutation induction while neutralized beam did not. The intrinsic reason was attributed to additional DNA deformation and contortion caused by ion charge exchange effect so that the ion beam induced DNA damage could hardly be completely repaired, whereas the neutralized beam induced DNA change could be more easily recoverable owing to absence of the additional DNA deformation and contortion.

  2. A comparative study on low-energy ion beam and neutralized beam modifications of naked DNA and biological effect on mutation

    Energy Technology Data Exchange (ETDEWEB)

    Sarapirom, S.; Thongkumkoon, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-02-01

    DNA conformation change or damage induced by low-energy ion irradiation has been of great interest owing to research developments in ion beam biotechnology and ion beam application in biomedicine. Mechanisms involved in the induction of DNA damage may account for effect from implanting ion charge. In order to check this effect, we used both ion beam and neutralized beam at keV energy to bombard naked DNA. Argon or nitrogen ion beam was generated and extracted from a radiofrequency (RF) ion source and neutralized by microwave-driven plasma in the beam path. Plasmid DNA pGFP samples were irradiated with the ion or neutralized beam in vacuum, followed by gel electrophoresis to observe changes in the DNA conformations. It was revealed that the ion charge played a certain role in inducing DNA conformation change. The subsequent DNA transfer into bacteria Escherichia coli (E. coli) for mutation analysis indicated that the charged ion beam induced DNA change had high potential in mutation induction while neutralized beam did not. The intrinsic reason was attributed to additional DNA deformation and contortion caused by ion charge exchange effect so that the ion beam induced DNA damage could hardly be completely repaired, whereas the neutralized beam induced DNA change could be more easily recoverable owing to absence of the additional DNA deformation and contortion.

  3. Comparative study of the usefulness of low energy Cs(+), Xe(+), and O(2)(+) ions for depth profiling amino-acid and sugar films.

    Science.gov (United States)

    Wehbe, Nimer; Houssiau, Laurent

    2010-12-15

    This work reports a comparative study on the capability of low energy primary ion beams for depth profiling nonpolymeric molecules including amino-acid and sugar layers. Due to their different behavior regarding depth profiling, phenylalanine and trehalose molecules are chosen as reference systems. Each molecule was dissolved in suitable solvent prior to spin-coating on clean silicon wafer. The film thicknesses were in the order of 70 and 100 nm for phenylalanine and trehalose respectively. Depth profiling feasibility were assessed first using Cs(+) as reactive sputtering ion at various energies. The results obtained under Cs(+) sputtering ions are compared afterward to those obtained under Xe(+) sputtering ions which are inert and have a mass very similar to Cs(+). In order to investigate the effect of oxygen, depth profiling are also performed using either Xe(+) under oxygen flooding or O(2)(+) as sputtering ions. While phenylalanine could be depth profiled successfully using Cs(+) ions, Xe(+) and O(2)(+) ions failed to retain any characteristic signal. The sputtering yields measured as a function of the ion beam energies were higher using Cs(+), in particular at low energies. The chemical reactivity of the cesium atoms being implanted during the sputtering process helps to prevent the loss of the molecular phenylalanine signal. In contrast, depth profiling of trehalose was more successful upon Xe(+) and O(2)(+) compared to Cs(+). In this case the sputtering yields were higher if Xe(+) primary ion is employed instead of Cs(+). The different trends observed in this study are interpreted using arguments involving the reactivity of the sputtering ions.

  4. Observational signatures of low-altitude low-energy ion motions up and down auroral field lines: a survey of sounding rocket measurements (Invited)

    Science.gov (United States)

    Lynch, K. A.; Fernandes, P. A.; Gayetsky, L.; Mella, M. R.; Hampton, D. L.; Lessard, M.; Zettergren, M. D.

    2013-12-01

    A number of auroral sounding rocket missions have sampled low-energy ion distribution functions near and in the ionospheric footpoint of auroral field lines, both on the dayside and the nightside, at altitudes ranging from a few hundred km to over 1000 km. The results, taken singly, can be confusing, given the variety of features. An overview of these observations, in the context of numerical modelling of the ionosphere, begins to reveal overall patterns of highly structured and temporally varying behaviors. In this talk we review observations from SCIFER (dayside, up to 1400 km), SCIFER2 (also dayside), SERSIO (dayside, lower altitude); and SIERRA, Cascades2, and MICA (all nightside, 300-500 km altitude.) A common feature in these auroral observations is that the ion distributions are seen to be moving either up (SIERRA low energies, MICA) or down (SCIFER, Cascades2, SIERRA medium eneriges) the field line with no obvious observational pattern. The downward moving distributions, particularly in the case of Cascades2, can be highly structured and varying in time, even showing dispersion signatures. Recent modelling efforts (Zettergren et al., this session) show structured patterns of upflow and downflow on auroral field lines consistent with these observations. Proper interpretation of sounding rocket case study ion flow observations must include the context given by 2-dimensional imagery and 2-dimensional (altitude and latitude) ionospheric modelling, as the net ion upflow from these low-altitude processes is a result of averaging over this variability.

  5. Low-Energy Proton Testing Methodology

    Science.gov (United States)

    Pellish, Jonathan A.; Marshall, Paul W.; Heidel, David F.; Schwank, James R.; Shaneyfelt, Marty R.; Xapsos, M.A.; Ladbury, Raymond L.; LaBel, Kenneth A.; Berg, Melanie; Kim, Hak S.; hide

    2009-01-01

    Use of low-energy protons and high-energy light ions is becoming necessary to investigate current-generation SEU thresholds. Systematic errors can dominate measurements made with low-energy protons. Range and energy straggling contribute to systematic error. Low-energy proton testing is not a step-and-repeat process. Low-energy protons and high-energy light ions can be used to measure SEU cross section of single sensitive features; important for simulation.

  6. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K., E-mail: k.prakrajang@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K.; Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanichapichart, P. [Membrane Science and Technology Research Center, Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkla 90112 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2012-09-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10{sup 15} to 10{sup 16} ions/cm{sup 2}. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  7. On the Effects of Pickup Ion-driven Waves on the Diffusion Tensor of Low-energy Electrons in the Heliosphere

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, N. Eugene, E-mail: n.eugene.engelbrecht@gmail.com [Center for Space Research, North-West University, Potchefstroom, 2522 (South Africa)

    2017-11-01

    The effects of Alfvén cyclotron waves generated due to the formation in the outer heliosphere of pickup ions on the transport coefficients of low-energy electrons is investigated here. To this end, parallel mean free path (MFP) expressions are derived from quasilinear theory, employing the damping model of dynamical turbulence. These are then used as inputs for existing expressions for the perpendicular MFP and turbulence-reduced drift coefficient. Using outputs generated by a two-component turbulence transport model, the resulting diffusion coefficients are compared with those derived using a more typically assumed turbulence spectral form, which neglects the effects of pickup ion-generated waves. It is found that the inclusion of pickup ion effects greatly leads to considerable reductions in the parallel and perpendicular MFPs of 1–10 MeV electrons beyond ∼10 au, which are argued to have significant consequences for studies of the transport of these particles.

  8. Multiple scattering of low energy H{sup +} ions in matter: Approximation of mean energy on the Sigmund and Winterbon model

    Energy Technology Data Exchange (ETDEWEB)

    Mekhtiche, A. [Laboratoire SNIRM, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32 El Alia, Bab Ezzouar, Algiers (Algeria); Faculté des Sciences et de la Technologie, Université Yahia Farès de Médéa (Algeria); Khalal-Kouache, K., E-mail: kkouache@yahoo.fr [Laboratoire SNIRM, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32 El Alia, Bab Ezzouar, Algiers (Algeria)

    2016-09-01

    In this paper, angular distributions of slow H{sup +} ions transmitted through different targets (Al, Ag and Au) are calculated using the model of Sigmund and Winterbon (SW) in the multiple scattering theory. Valdés and Arista (VA) developed a method extending the SW model by including the effect of energy loss in the calculation of angular distributions of transmitted ions. Another method has been proposed for such calculations: one can consider the SW model by using an average value for the energy of the ions inside the target. In this contribution, a new expression is proposed for the mean energy which gives a better agreement with the VA model than the precedent one at low energy. Different potentials have been considered to describe the interaction projectile-target atom in this study and the new expression is found to be independent of the interaction potential.

  9. A Parallel 3d Model for The Multi-Species Low Energy BeamTransport System of the RIA Prototype ECR Ion Source Venus

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J.; Leitner, D.; Todd, D.

    2005-05-16

    The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and to optimize the low energy beamline optics of the RIA front end,we have developed a new parallel three-dimensional model to simulate the low energy, multi-species ion beam formation and transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multisection overlapped computational domain has been used to break the original transport system into a number of each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in the Frenet-Serret coordinates for the bending magnet region. Some test examples and initial applications will also be presented.

  10. Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer.

    Science.gov (United States)

    Winklehner, D; Leitner, D; Cole, D; Machicoane, G; Tobos, L

    2014-02-01

    In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.

  11. Complementary low energy ion scattering and X-ray photoelectron spectroscopy characterization of polystyrene submitted to N{sub 2}/H{sub 2} glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Bonatto, F., E-mail: bonatto02@yahoo.com.br [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Rovani, S. [Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Kaufmann, I.R.; Soares, G.V. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Baumvol, I.J.R. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil); Universidade de Caxias do Sul, Caxias do Sul, Rio Grande do Sul 95070-560 (Brazil); Krug, C. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul 91509-900 (Brazil)

    2012-02-15

    Low energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) were used to access the elemental composition and chemical bonding characteristics of polystyrene (PS) surfaces sequentially treated by corona and glow discharge (plasma) processing in N{sub 2}/H{sub 2} ambient. The latter has shown activity as suppressor of pathogenic Staphylococcus epidermidis biofilms. LEIS indicated that oxygen from the corona discharge process is progressively replaced by nitrogen at the PS surface. XPS shows C=N and N-C=O chemical groups as significant inhibitors of bacterial adhesion, suggesting application in medical devices.

  12. Sputtering effect of low-energy ions on biological target: The analysis of sputtering product of urea and capsaicin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lili [Key Laboratory of Ion Beam Bio-Engineering, Institute of Technical Biology and Agriculture Engineering of Chinese Academy of Sciences, Shushanhu Road 350, Hefei 230031 (China); Xu, Xue [Rice Research Institute, Anhui Academy of Agricultural Sciences, Nongke South Road 40, Hefei 230031 (China); Wu, Yuejin, E-mail: yjwu@ipp.ac.cn [Key Laboratory of Ion Beam Bio-Engineering, Institute of Technical Biology and Agriculture Engineering of Chinese Academy of Sciences, Shushanhu Road 350, Hefei 230031 (China)

    2013-08-01

    Sputtering is a process whereby atoms are ejected from a solid target material due to bombardment of the target by energetic particles. Recent years, ion implantation was successfully applied to biological research based on the fragments sputtering and form open paths in cell structure caused by ion sputtering. In this study, we focused on urea and chilli pepper pericarp samples implanted with N{sup +} and Ar{sup +} ions. To investigate the sputtering effect, we designed a collecting unit containing a disk sample and a glass pipe. The urea content and capsaicin content recovered from glass pipes were adopted to represent the sputtering product. The result of urea showed that the sputtering effect is positively correlated with the ion energy and dose, also affected by the ion type. The result of capsaicin was different from that of urea at 20 keV and possibly due to biological complex composition and structure. Therefore the sputtering yield depended on both the parameters of incident ions and the state of target materials. The sputtering yield of urea was also simulated by computational method achieved through the TRIM program. The trajectories of primary and recoiled atoms were calculated on the basis of the binary collision approximation using Monte Carlo method. The experimental results were much higher than the calculated results. The possible explanation is that in the physical model the target were assumed as a disordered lattice and independent atoms, which is much less complicated than that of the biological models.

  13. Low-energy solar electrons and ions observed at Ulysses February-April, 1991 - The inner heliosphere as a particle reservoir

    Science.gov (United States)

    Roelof, E. C.; Gold, R. E.; Simnett, G. M.; Tappin, S. J.; Armstrong, T. P.; Lanzerotti, L. J.

    1992-01-01

    Ulysses observations at 2.5 AU of 38-315 keV electrons and 61-4752 keV ions during February-April 1991 suggest in several ways that, during periods of sustained high solar activity, the inner heliosphere serves as a 'reservoir' for low-energy solar particles. Particle increases were not associated one-to-one with large X-ray flares because of their poor magnetic connection, yet intensities in March-April remained well above their February levels. The rise phase of the particle event associated with the great flare of 2245UT March 22 lasted most of two days, while throughout the one-week decay phase, the lowest-energy ion fluxes were nearly equal at Ulysses and earth (IMP-8).

  14. Optimization of L(+)-Lactic Acid Fermentation Without Neutralisation of Rhizopus Oryzae Mutant RK02 by Low-Energy Ion Implantation

    Science.gov (United States)

    Li, Wen; Wang, Tao; Yang, Yingge; Liu, Dan; Fan, Yonghong; Wang, Dongmei; Yang, Qian; Yao, Jianming; Zheng, Zhiming; Yu, Zengliang

    2008-04-01

    In order to get an industrial strain which can yield a high concentration of lactic acid for ISPR (in situ product removal), the original strain Rhizopus oryzae RE3303 was mutated by low-energy ion beam implantation. A mutant RK02 was screened, and the factors such as the substrate concentration, nitrogen source concentration, inoculum size, seed age, aeration and temperature that affect the production of lactic acid were studied in detail. Under optimal conditions, the maximum concentration of L(+)-lactic acid reached 34.85 g/L after 30 h shake-flask cultivation without adding any neutralisation (5% Glucose added), which was a 146% increase in lactic acid production after ion implantation compared with the original strain. It was also shown that RK02 can be used in ISPR to reduce the number of times of separation.

  15. A Parallel 3D Model for the Multi-Species Low Energy Beam Transport System of the RIA Prototype ECR Ion Source VENUS

    CERN Document Server

    Qiang, Ji; Todd, Damon

    2005-01-01

    The driver linac of the proposed Rare Isotope Accelerator (RIA) requires a great variety of high intensity, high charge state ion beams. In order to design and optimize the low energy beam line optics of the RIA front end, we have developed a new parallel three-dimensional model to simulate the low energy, multi-species beam transport from the ECR ion source extraction region to the focal plane of the analyzing magnet. A multi-section overlapped computational domain has been used to break the original transport system into a number of independent subsystems. Within each subsystem, macro-particle tracking is used to obtain the charge density distribution in this subdomain. The three-dimensional Poisson equation is solved within the subdomain and particle tracking is repeated until the solution converges. Two new Poisson solvers based on a combination of the spectral method and the multigrid method have been developed to solve the Poisson equation in cylindrical coordinates for the beam extraction region and in...

  16. Statistical Theory of Low-Energy Reactive Collisions of N(+) Ions with H2, D2, and HD Molecules.

    Science.gov (United States)

    Grozdanov, Tasko P; McCarroll, Ronald

    2015-06-11

    A statistical treatment is presented of reactive collisions involving N(+) ions in the (3)Pja state with H2, D2, and HD molecules in rotation level j of the ground vibration state, leading to either the reaction products H + NH(+), D + ND(+), and D + NH(+) or H + ND(+). Unlike previous theoretical work, the fine-structure states of the N(+) ions are treated on an equal footing with other internal motions. The calculated cross sections for a given ion energy are averaged over a thermal distribution of initial fine-structure states of N(+) for a temperature of 300 K and over a thermal distribution of both the internal rotation states and translation energy of H2, D2, and HD for temperatures of 305 and 105 K in order to facilitate a comparison with experiment. The results are presented for a range of collision energies from 10 meV to 1 eV.

  17. Amorphous silicon carbonitride diaphragm for environmental-cell transmission electron microscope fabricated by low-energy ion beam induced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Matsutani, Takaomi, E-mail: matutani@ele.kindai.ac.jp [Kindai University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502 (Japan); Yamasaki, Kayo [Kindai University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502 (Japan); Imaeda, Norihiro; Kawasaki, Tadahiro [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2015-12-15

    An amorphous silicon carbonitride (a-SiCN) diaphragm for an environmental-cell transmission electron microscope (E-TEM) was fabricated by low-energy ion beam induced chemical vapor deposition (LEIBICVD) with hexamethyldisilazane (HMDSN). The films were prepared by using gaseous HMDSN and N{sub 2}{sup +} ions with energies ranging from 300 to 600 eV. The diaphragms were applied to Si (1 0 0) and a Cu grid with 100-μm-diameter holes. With increasing ion energy, these diaphragms became perfectly smooth surfaces (RMS = 0.43 nm at 600 eV), as confirmed by atomic force microscopy and TEM. The diaphragms were amorphous and transparent to 200 kV electrons, and no charge-up was observed. Fourier transform infrared spectra and X-ray photoelectron spectra revealed that the elimination of organic compounds and formation of Si–N and C–N bonds can be promoted in diaphragms by increasing the ion impact energy. The resistance to electron beams and reaction gases in the E-cell was improved when the diaphragm was formed with high ion energy.

  18. A Preliminary Study of the Application of a Model Animal-Caenorhabidity elegans' Exposure to a Low-Energy Ion Irradiation System

    Science.gov (United States)

    Liu, Xuelan; Cai, Kezhou; Feng, Huiyun; Xu, An; Yuan, Hang; Yu, Zengliang

    2007-10-01

    Because of the lack of suitable animal models adapted to high vacuum stress in the low-energy ion implantation system, the bio-effects ion irradiation with an energy less than 50 keV on multi-cellular animal individuals have never been investigated so far. The nematode Caenorhabditis elegans has proved to be an excellent animal model used for the study of a broad spectrum of biological issues. The purpose of this work was to investigate the viability of this animal under ion irradiation. We studied the protection effects of glycerol and trehalose on the enhancement of nematodes' ability to bear the vacuum stress. The results showed that the survival of the nematodes was enhanced remarkably under long and slow desiccation, even without glycerol and trehalose. 15% glycerol showed a better anti-vacuum stress effect on the nematodes than trehalose did under short-time desiccation. Low-temperature pre-treatment or post-treatment of the samples had no obvious effect on the survival scored after argon ion irradiation. Moreover, little effect was induced by 15% glycerol- and vacuum-exposure on germ cell apoptosis, compared to the untreated control sample. It issuggested that such treatment would provide relatively low background for genotoxic evaluations with ion irradiation.

  19. Electron stripping processes of H⁻ ion beam in the 80 kV high voltage extraction column and low energy beam transport line at LANSCE.

    Science.gov (United States)

    Draganic, I N

    2016-02-01

    Basic vacuum calculations were performed for various operating conditions of the Los Alamos National Neutron Science H(-) Cockcroft-Walton (CW) injector and the Ion Source Test Stand (ISTS). The vacuum pressure was estimated for both the CW and ISTS at five different points: (1) inside the H(-) ion source, (2) in front of the Pierce electrode, (3) at the extraction electrode, (4) at the column electrode, and (5) at the ground electrode. A static vacuum analysis of residual gases and the working hydrogen gas was completed for the normal ion source working regime. Gas density and partial pressure were estimated for the injected hydrogen gas. The attenuation of H(-) beam current and generation of electron current in the high voltage acceleration columns and low energy beam transport lines were calculated. The interaction of H(-) ions on molecular hydrogen (H2) is discussed as a dominant collision process in describing electron stripping rates. These results are used to estimate the observed increase in the ratio of electrons to H(-) ion beam in the ISTS beam transport line.

  20. Effect of Ge nanocluster assembly self-organization at pulsed irradiation by low-energy ions during heteroepitaxy on Si

    CERN Document Server

    Dvurechenskij, A V; Smagina, Z V

    2001-01-01

    Using the method of scanning microscopy one studied experimentally size distribution of Ge clusters formed in course of experiments of two types at Ge heteroepitaxy on Si(111): regular process of molecular-beam epitaxy (MBE); pulse irradiation by approx = 200 eV energy Ge ions. The experiments were conducted at 350 deg C temperature. Pulse irradiation by an ion beam during heteroepitaxy was detected to result in reduction of the average size of Ge clusters, in compacting of their density and in reduction of mean square deviation from the average value in contrast to similar values in experiments devoted to regular MBE

  1. Breeding of Coenzyme Q10 Produced Strain by Low-Energy Ion Implantation and Optimization of Coenzyme Q10 Fermentation

    Science.gov (United States)

    Xu, Dejun; Zheng, Zhiming; Wang, Peng; Wang, Li; Yuan, Hang; Yu, Zengliang

    2008-12-01

    In order to increase the production efficiency of coenzyme Q10, the original strain Agrobacterium tumefaciens ATCC 4452 was mutated by means of Nitrogen ions implantation. A mutant strain, ATX 12, with high contents of coenzyme Q10 was selected. Subsequently, the conditions such as carbohydrate concentration, nitrogen source concentration, inoculum's size, seed age, aeration and temperature which might affect the production of CoQ10 were investigated in detail. Under optimal conditions, the maximum concentration of the intracellular CoQ10 reached 200.3 mg/L after 80 h fed-batch fermentation, about 245% increasing in CoQ10 production after ion implantation, compared to the original strain.

  2. Bioelectrochemical systems-driven directional ion transport enables low-energy water desalination, pollutant removal, and resource recovery.

    Science.gov (United States)

    Chen, Xi; Liang, Peng; Zhang, Xiaoyuan; Huang, Xia

    2016-09-01

    Bioelectrochemical systems (BESs) are integrated water treatment technologies that generate electricity using organic matter in wastewater. In situ use of bioelectricity can direct the migration of ionic substances in a BES, thereby enabling water desalination, resource recovery, and valuable substance production. Recently, much attention has been placed on the microbial desalination cells in BESs to drive water desalination, and various configurations have optimized electricity generation and desalination performance and also coupled hydrogen production, heavy metal reduction, and other reactions. In addition, directional transport of other types of charged ions can remediate polluted groundwater, recover nutrient, and produce valuable substances. To better promote the practical application, the use of BESs as directional drivers of ionic substances requires further optimization to improve energy use efficiency and treatment efficacy. This article reviews existing researches on BES-driven directional ion transport to treat wastewater and identifies a few key factors involved in efficiency optimization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

    Science.gov (United States)

    Mahadtanapuk, S.; Teraarusiri, W.; Phanchaisri, B.; Yu, L. D.; Anuntalabhochai, S.

    2013-07-01

    Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60-80 keV to a beam fluence range of 2 × 1016-2 × 1017 ions/cm2. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 106 spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11).

  4. A review on recent light particle correlation data from heavy ion collisions at intermediate and low energies

    Energy Technology Data Exchange (ETDEWEB)

    Ardouin, D.

    1996-12-31

    A review of recent two-particle interferometry data for heavy-ion collisions in the domain of energy between ten and a few hundreds of MeV/nucleon is presented. Not only identical particles but unlike particle correlations have been used successfully as a probe for space-time dynamics of the collision process. Due to the availability of new dedicated charged particles or photon multi-detectors, the field of particle interferometry is moving to a good level of quantitative description: excitation energy and impact parameter dependences are now provided which should stimulate additional theoretical calculations for two-particle cross sections and emission of light fragments. (author). 102 refs.

  5. Sub microsecond notching of a negative hydrogen beam at low energy utilizing a magnetron ion source with a split extractor

    Energy Technology Data Exchange (ETDEWEB)

    Moehs, Douglas; /Fermilab

    2004-12-01

    A technique for sub-microsecond beam notching is being developed at 20 keV utilizing a Magnetron ion source with a slit extraction system and a split extractor. Each half of the extractor is treated as part of a 50 ohm transmission line which can be pulsed at {+-}700 volts creating a 1400 volt gradient. This system along with the associated electronics is electrically floated on top of a pulsed extraction voltage. A beam reduction of 95% has been observed at the end of the Fermilab 400 MeV Linac and 35% notching has recently been achieved in the Booster.

  6. Atomic Oxygen (ATOX) simulation of Teflon FEP and Kapton H surfaces using a high intensity, low energy, mass selected, ion beam facility

    Science.gov (United States)

    Vered, R.; Grossman, E.; Lempert, G. D.; Lifshitz, Y.

    1994-01-01

    A high intensity (greater than 10(exp 15) ions/sq cm) low energy (down to 5 eV) mass selected ion beam (MSIB) facility was used to study the effects of ATOX on two polymers commonly used for space applications (Kapton H and Teflon FEP). The polymers were exposed to O(+) and Ne(+) fluences on 10(exp 15) - 10(exp 19) ions/sq cm, using 30eV ions. A variety of analytical methods were used to analyze the eroded surfaces including: (1) atomic force microscopy (AFM) for morphology measurements; (2) total mass loss measurements using a microbalance; (3) surface chemical composition using x-ray photoelectron spectroscopy (XPS), and (4) residual gas analysis (RGA) of the released gases during bombardment. The relative significance of the collisional and chemical degradation processes was evaluated by comparing the effects of Ne(+) and O(+) bombardment. For 30 eV ions it was found that the Kapton is eroded via chemical mechanisms while Teflon FEP is eroded via collisional mechanisms. AFM analysis was found very powerful in revealing the evolution of the damage from its initial atomic scale (roughness of approx. 1 nm) to its final microscopic scale (roughness greater than 1 micron). Both the surface morphology and the average roughness of the bombarded surfaces (averaged over 1 micron x 1 micron images by the system's computer) were determined for each sample. For 30 eV a non linear increase of the Kapton roughness with the O(+) fluence was discovered (a slow increase rate for fluences phi less than 5 x 10(exp 17) O(+)/sq cm, and a rapid increase rate for phi greater than 5 x 10(exp 17) O(+)/sq cm). Comparative studies on the same materials exposed to RF and DC oxygen plasmas indicate that the specific details of the erosion depend on the simulation facility emphasizing the advantages of the ion beam facility.

  7. Assembling of a low energy ion beam analysis facility and use of Nuclear Microprobe techniques in geological studies

    Energy Technology Data Exchange (ETDEWEB)

    Utui, R.

    1996-11-01

    In this work, both PIXE and ion beam induced luminescence, or just Ionoluminescence (IL) were used for geochemical studies. The possibility of rapid absolute quantification of elements in the ppm level by PIXE combined with the yet higher sensitivity of IL to transition metals and Rare Earth Elements (REE) activators, in the absence of quenching phenomena, allow for a synergic use of the two methods in geological applications with enhanced sensitivity. IL and PIXE were combined for studying REE distribution in apatite minerals and ion beam induced damage in inorganic material in general with emphasis to synthetically grown zircon crystals doped with REE. Due to the sensitivity of IL to changes in chemical bonding in the material, beam damage effects can be studied even at low integrated doses, through wavelength shift or fading of the induced light. Micro PIXE technique was used for studying profile concentrations of trace elements in pyrite grains and of elements used as geothermometers. Geothermometry allowed to assess the cooling rates in iron meteorites and the mineralization conditions in metamorphic rocks, attempting to describe the tectonic history of the terranes, with application in petrologic studies and geological prospecting. 148 refs.

  8. Investigation of various phases of Fe–Si structures formed in Si by low energy Fe ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Lakshantha, Wickramaarachchige J.; Dhoubhadel, Mangal S.; Reinert, Tilo; McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Rout, Bibhudutta, E-mail: bibhu@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Center for Advanced Research and Technology, University of North Texas, 3940 North Elm Street, Denton, TX 76207 (United States)

    2015-12-15

    The compositional phases of ion beam synthesized Fe–Si structures at two high fluences (0.50 × 10{sup 17} atoms/cm{sup 2} and 2.16 × 10{sup 17} atoms/cm{sup 2}) were analyzed using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The distribution of Fe implanted in Si was simulated using a dynamic simulation code (TRIDYN) incorporating target sputtering effects. The Fe depth profiles in the Si matrix were confirmed with Rutherford backscattering spectrometry (RBS) and XPS depth profiling using Ar-ion etching. Based on XPS binding energy shift and spectral asymmetry, the distribution of stable Fe–Si phases in the substrate was analyzed as a function of depth. Results indicate Fe implantation with a fluence of 0.50 × 10{sup 17} atoms/cm{sup 2} and subsequent thermal annealing produce mainly the β-FeSi{sub 2} phase in the whole thickness of the implanted region. But for the samples with a higher fluence Fe implantation, multiple phases are formed. Significant amount of Fe{sub 3}Si phase are found at depth intervals of 14 nm and 28 nm from the surface. Initially, as-implanted samples show amorphous Fe{sub 3}Si formation and further thermal annealing at 500 °C for 60 min formed crystalline Fe{sub 3}Si structures at the same depth intervals. In addition, thermal annealing at 800 °C for 60 min restructures the Fe{sub 3}Si clusters to form FeSi{sub 2} and FeSi phases.

  9. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Directory of Open Access Journals (Sweden)

    M. Guevara-Bertsch

    2016-03-01

    Full Text Available We investigate the variation of the oscillation frequency of the Mg2+ and O2− ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  10. Detection of the adsorption of water monolayers through the ion oscillation frequency in the magnesium oxide lattice by means of low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Guevara-Bertsch, M.; Avendaño, E. [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Ramírez-Hidalgo, G. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Sección de Física Teórica, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Chavarría-Sibaja, A.; Araya-Pochet, J. A. [Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Herrera-Sancho, O. A., E-mail: oscar-andrey.herrera@uibk.ac.at [Escuela de Física, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Centro de Investigación en Ciencia e Ingeniería de Materiales, Universidad de Costa Rica, 2060 San Pedro, San José (Costa Rica); Institut für Quantenoptik und Quanteninformation, Österreichische Akademie der Wissenschaften, Technikerstr. 21a, 6020 Innsbruck (Austria)

    2016-03-15

    We investigate the variation of the oscillation frequency of the Mg{sup 2+} and O{sup 2−} ions in the magnesium oxide lattice due to the interactions of the surface with water monolayers by means of Low Energy Electron Diffraction. Our key result is a new technique to determine the adsorbate vibrations produced by the water monolayers on the surface lattice as a consequence of their change in the surface Debye temperature and its chemical shift. The latter was systematically investigated for different annealing times and for a constant external thermal perturbation in the range of 110–300 K in order to accomplish adsorption or desorption of water monolayers in the surface lattice.

  11. Low-energy oxygen ion beam assisted growth of BaO/EuBa2Cu3O7-δ multilayers in ultrahigh vacuum

    Science.gov (United States)

    Pindoria, Govind; Kawaguchi, K.; Morishita, Tadataka

    1996-07-01

    Molecular beam epitaxial growth of cuprate oxide superconducting thin films using a mass separated, low energy, O+ beam source, is discussed. The mono-valent O+ ion is chemically, highly reactive, and its kinetic energy at 10's of electron volts, is significant. It allows the growth of REBa2Cu3O7-(delta ) (REBCO) thin films at low pressures and temperatures. The effective over-pressure of the O+ ions at the substrate being 2 X 10-7 Torr, and the optimum growth temperature 500 degrees C. These conditions are below the currently accepted stability line for the growth of REBCO thin films. We characterize the physical and chemical properties of the O+ ion beam, and its effect on superconducting thin films. We have grown highly crystalline BaO and EuBa2Cu3O7-(delta ) (EBCO) thin films on SrTiO3 substrates. The full width at half maximum of the rocking curves for BaO(002) equals 0.07 degrees and that for the EBCO (005) peak equals 0.05 degrees. Also, we found that BaO is a good insulating material (1.7 X 1013 (Omega) m at 4K), with an excellent lattice match to EBCO, therefore a suitable candidate as an insulating layer in multilayer structures. The results of the first growth studies of BaO/EBCO multilayers are discussed.

  12. Combined quantum-mechanics/molecular-mechanics dynamics simulation of A-DNA double strands irradiated by ultra-low-energy carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ngaojampa, C.; Nimmanpipug, P. [Computer Simulation and Modeling Laboratory (CSML), Department of Chemistry and Center for Innovation Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.t [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Lee, V.S., E-mail: vannajan@gmail.co [Computer Simulation and Modeling Laboratory (CSML), Department of Chemistry and Center for Innovation Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2011-02-15

    In order to promote understanding of the fundamentals of ultra-low-energy ion interaction with DNA, molecular dynamics simulations using combined quantum-mechanics/molecular-mechanics of poly-AT and poly-GC A-DNA double strands irradiated by <200 eV carbon ions were performed to investigate the molecular implications of mutation bias. The simulations were focused on the responses of the DNA backbones and nitrogenous bases to irradiation. Analyses of the root mean square displacements of the backbones and non-hydrogen atoms of base rings of the simulated DNA structure after irradiation revealed a potential preference of DNA double strand separation, dependent on the irradiating energy. The results show that for the backbones, the large difference in the displacement between poly-GC and poly-AT in the initial time period could be the reason for the backbone breakage; for the nitrogenous base pairs, A-T is 30% more sensitive or vulnerable to ion irradiation than G-C, demonstrating a preferential, instead of random, effect of irradiation-induced mutation.

  13. Computational Modeling of Laboratory X-ray Emission due to Low-Energy Collisions of H-like and He-like ions with H2

    Science.gov (United States)

    Miller, Ansley; Mullen, Patrick Dean; Cumbee, Renata; Stancil, Phillip C.; Leutenegger, Maurice A.

    2016-06-01

    Charge exchange between highly-charged ions and neutral molecules occurs when the solar wind, or other astrophysical plasmas, collide with cool gas. This process emits observable X-rays with specific line intensities. Recent CX experiments at Lawrence Livermore National Laboratory measured the X-ray hardness ratios of low-energy collisions between hydrogen- and helium-like ions with H2 (Leutenegger et al. 2010). Using our recently developed X-ray modeling package, Kronos_v2 (Mullen et al. 2016), which utilizes multi-channel Landau-Zener charge exchange cross sections, we have computed theoretical hydrogen-like hardness ratios to aid in interpretation of the experimental data. While the computed hardness ratios are somewhat smaller than the experiment, it shows better agreement than earlier classical trajectory predictions. We are also in the process of building Kronos_v3; further enhancing the comprehensive charge exchange database to include helium-like and multielectron ions to allow for comparison with experiments and for models of hot astrophysical environments such as supernova remnants, star-forming galaxies, and galaxy clusters.Leutenegger, M. et al. 2010, Phys. Rev. Lett., 105, 063201Mullen, P. D. et al., 2016, ApJS, in press

  14. Investigation of Low-Energy Tilted Ion Implantation for Fin-Type Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor Extension Doping

    Science.gov (United States)

    Yongxun Liu,; Takashi Matsukawa,; Kazuhiko Endo,; Shinich O'uchi,; Kunihiro Sakamoto,; Junichi Tsukada,; Yuki Ishikawa,; Hiromi Yamauchi,; Meishoku Masahara,

    2010-04-01

    The low-energy tilted ion implantation (I/I) for fin-type double-gate metal-oxide-semiconductor field-effect transistor (FinFET) source-drain (SD) extension doping is systematically investigated experimentally by fabricating a series of n+-polycrystalline silicon (poly-Si) gate n-channel FinFETs under different I/I conditions. The on-state current (ION) versus off-state current (IOFF) and the SD parasitic resistance (Rp) are used for benchmarking the performance of the fabricated devices to investigate the optimal extension I/I conditions, including dose (D) and tilted angle (θ), at a fixed low energy of 5 keV. It is experimentally found that the best extension I/I conditions are D = 4× 1014 cm-2 and θ = 60°. With further increasing D, the device performance deteriorates owing to the incomplete recrystallization of amorphous regions in the thin extension regions. In the case of θ = 0°, marked increment and fluctuations in Rp are observed because the implant atoms scatter out randomly from each extension region. The Rp value of the FinFETs fabricated under the above best I/I conditions is comparable to that of devices fabricated by the solid-phase diffusion of phosphors from phosphosilicate glass (PSG). This indicates that the extension I/I conditions of D = 4× 1014 cm-2 and θ = 60° are almost optimal and is very effective for high-performance FinFET fabrication.

  15. Breeding for blast-disease-resistant and high-yield Thai jasmine rice (Oryza sativa L. cv. KDML 105) mutants using low-energy ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Mahadtanapuk, S. [School of Agriculture and Natural Resources, University of Phayao, Phayao 56000 (Thailand); Teraarusiri, W. [Central Laboratory, University of Phayao, Phayao 56000 (Thailand); Phanchaisri, B. [Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@frnf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Anuntalabhochai, S., E-mail: burinka@hotmail.com [Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2013-07-15

    Highlights: •N-ion beam bombarded Thai jasmine rice seeds to induce mutation. •Mutants with blast-disease resistance and high yield were screened. •Gene involved in the blast-disease resistance was analyzed. •The gene responsible for the resistance was linked to Spotted leaf protein 11. -- Abstract: Low-energy ion beam was applied on mutation induction for plant breeding of blast-disease-resistant Thai jasmine rice (Oryza sativa L. cv. KDML 105). Seeds of the wild-type rice were bombarded in vacuum by nitrogen ion beam at energy of 60–80 keV to a beam fluence range of 2 × 10{sup 16}–2 × 10{sup 17} ions/cm{sup 2}. The ion-bombarded rice seeds were grown in soil for 2 weeks as transplanted rice in plastic pots at 1 seedling/pot. The seedlings were then screened for blast resistance by Pyricularia grisea inoculation with 10{sup 6} spores/ml concentrations. The blast-resistant rice mutant was planted up to F6 generation with the consistent phenotypic variation. The high percentage of the blast-disease-resistant rice was analyzed with DNA fingerprint. The HAT-RAPD (high annealing temperature-random amplified polymorphic DNA) marker revealed the modified polymorphism fragment presenting in the mutant compared with wild type (KDML 105). The cDNA fingerprints were investigated and the polymorphism fragment was subcloned into pGEM-T easy vector and then sequenced. The sequence of this fragment was compared with those already contained in the database, and the fragment was found to be related to the Spotted leaf protein 11 (Spl11)

  16. Low Energy Electron and Nuclear Recoil Thresholds in the DRIFT-II Negative Ion TPC for Dark Matter Searches

    CERN Document Server

    Burgos, S; Forbes, J; Ghag, C; Gold, M; Hagemann, C; Kudryavtsev, V A; Lawson, T B; Loomba, D; Majewski, P; Muna, D; Murphy, A St J; Paling, S M; Petkov, A; Plank, S J S; Robinson, M; Sanghi, N; Snowden-Ifft, D P; Spooner, N J C; Turk, J; Tziaferi, E

    2009-01-01

    Understanding the ability to measure and discriminate particle events at the lowest possible energy is an essential requirement in developing new experiments to search for weakly interacting massive particle (WIMP) dark matter. In this paper we detail an assessment of the potential sensitivity below 10 keV in the 1 m^3 DRIFT-II directionally sensitive, low pressure, negative ion time projection chamber (NITPC), based on event-by-event track reconstruction and calorimetry in the multiwire proportional chamber (MWPC) readout. By application of a digital smoothing polynomial it is shown that the detector is sensitive to sulfur and carbon recoils down to 3.5 and 2.2 keV respectively, and 1.2 keV for electron induced tracks. The energy sensitivity is demonstrated through the 5.9 keV gamma spectrum of 55Fe, where the energy resolution is sufficient to identify the escape peak. In addition to recoil direction reconstruction for WIMP searches this sensitivity suggests new prospects for applications also in KK axion s...

  17. Prize for Industrial Applications of Physics Talk: Low energy spread Ion source for focused ion beam systems-Search for the holy grail

    Science.gov (United States)

    Ward, Bill

    2011-03-01

    In this talk I will cover my personal experiences as a serial entrepreneur and founder of a succession of focused ion beam companies (1). Ion Beam Technology, which developed a 200kv (FIB) direct ion implanter (2). Micrion, where the FIB found a market in circuit edit and mask repair, which eventually merged with FEI corporation. and (3). ALIS Corporation which develop the Orion system, the first commercially successful sub-nanometer helium ion microscope, that was ultimately acquired by Carl Zeiss corporation. I will share this adventure beginning with my experiences in the early days of ion beam implantation and e-beam lithography which lead up to the final breakthrough understanding of the mechanisms that govern the successful creation and operation of a single atom ion source.

  18. Simultaneous Counter-Ion Co-Deposition a Technique Enabling Matrix Isolation Spectroscopy Studies Using Low-Energy Beams of Mass-Selected Ions

    Science.gov (United States)

    Ludwig, Ryan M.; Moore, David T.

    2014-06-01

    Matrix isolation spectroscopy was first developed in Pimentel's group during the 1950's to facilitate spectroscopic studies of transient species. Cryogenic matrices of condensed rare gases provide an inert chemical environment with facile energy dissipation and are transparent at all wavelengths longer than vacuum UV, making them ideal for studying labile and reactive species such as radicals, weakly bound complexes, and ions. Since frozen rare gases are poor electrolytes, studies of ions require near-equal populations of anions and cations in order to stabilize the number densities required for spectroscopic experiments. Many techniques for generation of ions for using in matrix isolation studies satisfy this criterion intrinsically, however when ion beams generated in external sources are deposited, the counter-ions typically arise via secondary processes that are at best loosely controlled. It has long been recognized that it would be desirable to stabilize deposition of mass-selected ions generated in an external source using simultaneous co-deposition of a beam of counter-ions, however previous attempts to achieve this have been reported as unsuccessful. The Moore group at Lehigh has demonstrated successful experiments of this type, using mass-selected anions generated from a metal cluster source, co-deposited with a balanced current of cations generated in a separate electron ionization source. This talk will focus on the details of the technique, and present some results from proof-of-concept studies on anionic copper carbonyl complexes formed in argon matrices following co-deposition of Cu- with Ar+ or Kr+. Funding support from NSF CAREER Award CHE-0955637 is gratefully acknowledged. Whittle et al., J. Chem. Phys. 22, p.1943 (1954); Becker et al., J. Chem. Phys. 25, p.224 (1956). Godbout et al., J. Chem. Phys. 96, p.2892 (1996). Sabo et al., Appl. Spectrosc. 45, p. 535 (1991).

  19. Analysis of a Partial Male-Sterile Mutant of Arabidopsis thaliana Isolated from a Low-Energy Argon Ion Beam Mutagenized Pool

    Science.gov (United States)

    Xu, Min; Bian, Po; Wu, Yuejin; Yu, Zengliang

    2008-04-01

    A screen for Arabidopsis fertility mutants, mutagenized by low-energy argon ion beam, yielded two partial male-sterile mutants tc243-1 and tc243-2 which have similar phenotypes. tc243-2 was investigated in detail. The segregation ratio of the mutant phenotypes in the M2 pools suggested that mutation behaved as single Mendelian recessive mutations. tc243 showed a series of mutant phenotypes, among which partial male-sterile was its striking mutant characteristic. Phenotype analysis indicates that there are four factors leading to male sterility. a. Floral organs normally develop inside the closed bud, but the anther filaments do not elongate sufficiently to position the locules above the stigma at anthesis. b. The anther locules do not dehisce at the time of flower opening (although limited dehiscence occurs later). c. Pollens of mutant plants develop into several types of pollens at the trinucleated stage, as determined by staining with DAPI (4',6-diamidino-2-phenylindole), which shows a variable size, shape and number of nucleus. d. The viability of pollens is lower than that of the wild type on the germination test in vivo and vitro.

  20. P.I.A.F.E project: long distance transport of low energy exotic ions; Projet P.I.A.F.E: transport d`ions exotiques de basse energie sur longue distance

    Energy Technology Data Exchange (ETDEWEB)

    Nibart, V.

    1996-01-17

    The aim of the PIAFE project is the long distance (400 m) transport of a low energy radioactive ion beam from the ILL (Institut Laue Langevin) to the ISN (Institut des Sciences Nucleaires) of Grenoble (France). The production, extraction, ionization and mass separation of ions is performed by the ILL, while the transformation of ions into multicharged ions, their stripping and acceleration is carried out at the ISN. Theoretical and experimental studies for a simple an original guidance solution have shown that such a long transport, even delicate, should not encounter any major difficulty. The main objectives of this thesis is the technical realization of a 18 m section of this transport line. The problem of supports and focalizing elements alignment has been solved together with the other problems such as: the central trajectory deviation due to alignment defects and to the Earth`s magnetic field; the particle losses due to charge exchange with the residual gas and the emittance increase by Coulomb scattering. It has been demonstrated that a 90% transmission can be obtained using a 25 keV energy and a 10{sup -7} mbar vacuum. Experimental measurements using a rubidium ion source have allowed to validate a theoretical model of emittance increase due to the residual gas-ions interactions. The increase of emittance with respect to the pressure has been measured using four residual gases of different mass. (J.S.). 29 refs., 61 figs., 19 tabs., 8 photos., 4 appends.

  1. The response of a fast scintillator screen (YAP:Ce) to low energy ions (0-40 keV) and its use to detect fast-ion-loss in stellarator TJ-II

    Energy Technology Data Exchange (ETDEWEB)

    Martínez, M., E-mail: marcos.martinez@externos.ciemat.es [Universidad Carlos III de Madrid, Leganés (Spain); Zurro, B.; Baciero, A.; Jiménez-Rey, D.; Malo, M. [Laboratorio Nacional de Fusión, CIEMAT, Madrid (Spain); Tribaldos, V. [Departamento de Física, Universidad Carlos III de Madrid, Leganés (Spain); Crespo, M. T.; Muñoz, D. [Laboratorio de Metrología de Radiaciones Ionizantes, CIEMAT, Madrid (Spain)

    2016-11-15

    A systematic study of scintillation materials was undertaken to improve the time resolution of the fast ion diagnostic currently installed at TJ-II stellarator. It was found that YAP:Ce (formula YAlO{sub 3}:Ce, Yttrium Aluminum Perovskite doped with Cerium) ionoluminescence offers better sensitivity and time response compared to the standard detector material, SrGa{sub 2}S{sub 4}:Eu (TG-Green), currently used in TJ-II. A comparison between both materials was carried out by irradiating them with H{sup +} ions of up to 40 keV using a dedicated laboratory setup. It is found that for the low energy ions of interest at TJ-II, YAP:Ce offers 20 times higher sensitivity than TG-Green and much faster decay time, 27 ns versus 540 ns. It is expected that the use of YAP:Ce in combination with a faster data acquisition and an ion counting software as part of the TJ-II ion luminescent probe will provide 20 times faster data on ion loss.

  2. The response of a fast scintillator screen (YAP:Ce) to low energy ions (0-40 keV) and its use to detect fast-ion-loss in stellarator TJ-II.

    Science.gov (United States)

    Martínez, M; Zurro, B; Baciero, A; Jiménez-Rey, D; Tribaldos, V; Malo, M; Crespo, M T; Muñoz, D

    2016-11-01

    A systematic study of scintillation materials was undertaken to improve the time resolution of the fast ion diagnostic currently installed at TJ-II stellarator. It was found that YAP:Ce (formula YAlO3:Ce, Yttrium Aluminum Perovskite doped with Cerium) ionoluminescence offers better sensitivity and time response compared to the standard detector material, SrGa2S4:Eu (TG-Green), currently used in TJ-II. A comparison between both materials was carried out by irradiating them with H+ ions of up to 40 keV using a dedicated laboratory setup. It is found that for the low energy ions of interest at TJ-II, YAP:Ce offers 20 times higher sensitivity than TG-Green and much faster decay time, 27 ns versus 540 ns. It is expected that the use of YAP:Ce in combination with a faster data acquisition and an ion counting software as part of the TJ-II ion luminescent probe will provide 20 times faster data on ion loss.

  3. Morphological and Anatomical Assessment of KDML 105 (Oryza sativa L. spp. indica and Its Mutants Induced by Low-Energy Ion Beam

    Directory of Open Access Journals (Sweden)

    Narumol BOONRUENG

    2013-05-01

    Full Text Available Thai jasmine rice KDML 105 is consumed around the world. BKOS, PKOS and TKOS are new cultivars produced from low-energy ion beam induction in KDML 105. The purpose of this study is to compare the morphology and anatomy between KDML 105 and the three new cultivars. Seeds of the four cultivars were germinated and grown in pots until flowering phase. The plants' organs were observed and the lengths of culms, ligules, leaves and panicles were measured. Leaf surface area was calculated and numbers of roots, spikelets and tillers were counted. BKOS and PKOS had significantly shorter culms than KDML 105 and TKOS. The largest leaf area was found in KDML 105 followed by TKOS, BKOS and PKOS, respectively. Numbers of roots and tillers in BKOS and TKOS were significantly fewer than those in KDML 105 and PKOS. The number of spikelets per plant in BKOS was the lowest among all cultivars. For anatomical comparison, cross sections of culms and roots were observed. All plants had a similar arrangement of tissues, but the number and size of cells were different. Furthermore, longitudinal sections of culms showed that the lengths of epidermal and parenchyma cells were directly related with the length of the culm. To compare the leaves, both stomata and epidermal cells were counted and the lengths of the guard cells were measured. The lengths of guard cells of BKOS and PKOS were shorter, but the stomatal density and the stomatal index were significantly greater than those of KDML 105. For TKOS, though the length of guard cells was shorter than that in KDML 105, the difference was not significant. However, the stomatal density and stomatal index were significantly higher than those in KDML 105.

  4. Tuning of the optical properties of In-rich In{sub x}Ga{sub 1−x}N (x=0.82−0.49) alloys by light-ion irradiation at low energy

    Energy Technology Data Exchange (ETDEWEB)

    De Luca, Marta; Polimeni, Antonio; Capizzi, Mario [Dipartimento di Fisica, Sapienza Università di Roma, P.le A. Moro 2, 00185 Roma (Italy); Pettinari, Giorgio [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Ciatto, Gianluca; Fonda, Emiliano [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif sur Yvette Cedex (France); Amidani, Lucia; Boscherini, Federico [Department of Physics and CNISM, University of Bologna, V. le C. Berti Pichat 6/2, 40127 Bologna (Italy); Filippone, Francesco; Bonapasta, Aldo Amore [CNR-Istituto di Struttura della Materia (ISM), Via Salaria Km 29.5, CP 10, I-00016 Monterotondo Stazione (Italy); Knübel, Andreas; Cimalla, Volker; Ambacher, Oliver [Fraunhofer Institute for Applied Solid State Physics, Tullastr. 72, 79108 Freiburg (Germany); Giubertoni, Damiano; Bersani, Massimo [CMM - Fondazione Bruno Kessler, Trieste, via Sommarive 18, 38100, Povo Trento (Italy)

    2013-12-04

    The effects of low-energy irradiation by light ions (H and He) on the properties of In-rich In{sub x}Ga{sub 1−x}N alloys are investigated by optical and structural techniques. H-irradiation gives rise to a remarkable blue-shift of light emission and absorption edge energies. X-ray absorption measurements and first-principle calculations address the microscopic origin of these effects.

  5. Low energy supersymmetry phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Baer, H.; Chen, C.H. [Florida State Univ., Tallahassee, FL (United States). Dept. of Physics; Bartl, A. [Universitaet Wien (Austria). Institut fuer Theoretische Physik; Feng, J. [Stanford Univ., CA (United States). Stanford Linear Accelerator Center; Fujii, K. [National Lab. for High Energy Physics, Tsukuba (Japan); Gunion, J. [Univ. of California, Davis, CA (United States). Dept. of Physics; Kamon, T.; Lopez, J.L. [Texas A& M Univ., College Station, TX (United States). Dept. of Physics; Kao, C. [Univ. of Rochester, NY (United States). Dept. of Physics and Astronomy] [and others

    1995-04-01

    The authors summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, they evaluate the capabilities of various e{sup +}e{sup {minus}}, p{bar p} and pp colliders to discover evidence for supersymmetric particles. Furthermore, assuming supersymmetry is discovered, they discuss capabilities of future facilities to disentangle the anticipated spectrum of super-particles, and, via precision measurements, to test mass and coupling parameters for comparison with various theoretical expectations. The authors then comment upon the complementarity of proposed hadron and e{sup +}e{sup {minus}} machines for a comprehensive study of low energy supersymmetry.

  6. Low Energy Supersymmetry Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Feng, J.

    2003-06-16

    We summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, we evaluate the capabilities of various e{sup +}e{sup -}, p{bar p} and pp colliders to discover evidence for supersymmetric particles. Furthermore, assuming supersymmetry is discovered, we discuss capabilities of future facilities to dis-entangle the anticipated spectrum of super-particles, and, via precision measurements, to test mass and coupling parameters for comparison with various theoretical expectations. We comment upon the complementarity of proposed hadron and e{sup +}e{sup -} machines for a comprehensive study of low energy supersymmetry.

  7. Low energy supersymmetry phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Baer, H.; Chen, C.H. [Florida State Univ., Tallahassee, FL (United States). Dept. of Physics; Bartl, A. [Univ. Wien (Austria). Inst. fuer Theoretische Physik] [and others

    1995-03-01

    The authors summarize the current status and future prospects for low energy (weak scale) supersymmetry. In particular, they evaluate the capabilities of various e{sup +}e{sup {minus}}, p{anti p} and pp colliders to discover evidence for supersymmetric particles. Furthermore, assuming supersymmetry is discovered, they discuss capabilities of future facilities to disentangle the anticipated spectrum of superparticles, and, via precision measurements, to test mass and coupling parameters for comparison with various theoretical expectations. They comment upon the complementarity of proposed hadron and e{sup +}e{sup {minus}} machines for a comprehensive study of low energy supersymmetry.

  8. Design of a High-Perveance Electron Gun for Electron Cooling in the Low Energy Ion Ring (LEIR) at CERN and Non-Interceptive Proton Beam Profile Monitors using Ion or Atomic Probe Beams

    CERN Document Server

    Dimopoulou, Christina

    2002-01-01

    For an efficient electron cooling of the low-energy Pb54+ ions in LEIR a high-perveance (at least 3.6microperv) electron gun had to be designed. The theoretical study of electron guns has shown that the required perveance can be achieved by using a convex cathode. The gun should be immersed in a strong magnetic field (B=2-6kG) in order to obtain a parallel beam with very low transverse energy (typically 0.1 eV). This idea was confirmed by experimental tests at Fermilab. An adiabatic magnetic expansion is foreseen after the gun in order to reduce the magnetic field to accpetable values (0.6-1 kG) in the cooling section. The internal geometry of a convex cathode gun for the LEIR electron cooler together with the parameters of the magnetic expansion are proposed. The scheme fulfils the requirements. In addition, the author has made an important contribution in the field of beam instrumentation for the LHC and other accelerators at CERN. A profile monitor has been developed that uses a Xe ion probe beam that inte...

  9. Dissociative scattering of low-energy SiF{sub 3}{sup +} and SiF{sup +} ions (5-200 eV) on Cu(100) surface

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Hiroyuki; Baba, Yuji; Sasaki, T.A. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Dissociative scattering of molecular SiF{sub 3}{sup +} and SiF{sup +} ions from a Cu(100) single crystal surface has been investigated in the incident energy range from 5 eV to 200 eV with a scattering angle of 77deg. The scattered ion intensity of dissociative ions and parent molecular ions were measured as a function of incident ion energy. The observed data show that onset energies of dissociation for SiF{sub 3}{sup +} and SiF{sup +} ions are 30 eV and 40 eV, respectively. The obtained threshold energies are consistent with a impulsive collision model where the dissociation of incident ion is caused by vibrational excitation during collision. (author)

  10. Tetrakis-amido high flux membranes

    Science.gov (United States)

    McCray, S.B.

    1989-10-24

    Composite RO membranes of a microporous polymeric support and a polyamide reaction product of a tetrakis-aminomethyl compound and a polyacylhalide are disclosed, said membranes exhibiting high flux and good chlorine resistance.

  11. High-flux solar photon processes

    Energy Technology Data Exchange (ETDEWEB)

    Lorents, D C; Narang, S; Huestis, D C; Mooney, J L; Mill, T; Song, H K; Ventura, S [SRI International, Menlo Park, CA (United States)

    1992-06-01

    This study was commissioned by the National Renewable Energy Laboratory (NREL) for the purpose of identifying high-flux photoprocesses that would lead to beneficial national and commercial applications. The specific focus on high-flux photoprocesses is based on the recent development by NREL of solar concentrator technology capable of delivering record flux levels. We examined photolytic and photocatalytic chemical processes as well as photothermal processes in the search for processes where concentrated solar flux would offer a unique advantage. 37 refs.

  12. Low Energy Nuclear Reactions?

    CERN Multimedia

    CERN. Geneva; Faccini, R.

    2014-01-01

    After an introduction to the controversial problem of Low Energy Nuclear Reactions (LENR) catalyzed by neutrons on metallic hydride surfaces we present the results of an experiment, made in collaboration with ENEA Labs in Frascati, to search neutrons from plasma discharges in electrolytic cells. The negative outcome of our experiment goes in the direction of ruling out those theoretical models expecting LENR to occur in condensed matter systems under specific conditions. Our criticism on the theoretical foundations of such models will also be presented.

  13. Low-energy neutrinos

    CERN Document Server

    Ludhova, Livia

    2016-01-01

    There exist several kinds of sources emitting neutrinos in the MeV energy range. These low-energy neutrinos from different sources can be often detected by the same multipurpose detectors. The status-of-art of the feld of solar neutrinos, geoneutrinos, and the search for sterile neutrino with artifcial neutrino sources is provided here; other neutrino sources, as for example reactor or high-energy neutrinos, are described elsewhere. For each of these three felds, the present-day motivation and open questions, as well as the latest experimental results and future perspectives are discussed.

  14. Extra Low ENergy Antiproton

    CERN Multimedia

    To produce dense antiproton beams at very low energies (110 keV), it has been proposed to install a small decelerator ring between the existing AD ring and the experimental area. Phase-space blowup during deceleration is compensated by electron cooling such that the final emittances are comparable to the 5MeV beam presently delivered by the AD. An immediate consequence is a significant increase in the number of trapped antiprotons at the experiments as outlined in the proposal CERN/SPSC-2009-026; SPCS-P-338. This report describes the machine parameters and layout of the proposal ELENA (Extra Low ENergy Antiproton)ring also gives an approximate estimate of cost and manpower needs. Since the initial estimate, published in 2007 (CERN-AB-2007-079), the ELENA design has evolved considerably. This is due to a new location in the AD hall to acommodate for the possibility of another experimental zone, as suggested by the SPCS, and also due to improvements in the ring optics and layout. The cost estimate that is prese...

  15. Nondissociative low-energy electron attachment to SF6, C6F6, C10F8, and c-C7F14: Negative ion lifetimes

    Science.gov (United States)

    Suess, L.; Parthasarathy, R.; Dunning, F. B.

    2002-12-01

    The lifetimes of long-lived parent anions formed by nondissociative electron attachment to SF6, C6F6, C10F8, and c-C7F14 are investigated. The ions are created via electron transfer in collisions with K(np) Rydberg atoms and their lifetimes determined by observing their decay using a Penning ion trap. The measured lifetimes vary widely from target to target and range from ˜10 μs for C6F6- to ˜10 ms for SF6-. The present results are compared with values obtained in earlier free-electron studies.

  16. Evaluation of the relative thermoluminescence efficiency of LiF:Mg,Ti and LiF:Mg,Cu,P TL detectors to low-energy heavy ions

    DEFF Research Database (Denmark)

    Gieszczyk, W.; Bilski, P.; Olko, P.

    2013-01-01

    The most popular types of LiF-based thermoluminescent (TL) detectors, LiF:Mg,Ti (MTS-N) and LiF:Mg,Cu,P (MCP-N), have been investigated, with respect to their dose (fluence) response and relative TL efficiency to different ion species. The detectors were irradiated using the nitrogen, iron, krypton...

  17. Inside bluetooth low energy

    CERN Document Server

    Gupta, Naresh

    2013-01-01

    Bluetooth Low Energy (LE) is one of the latest enhancement to Bluetooth technology and, as the name suggests, it is aimed at ultra low power devices, such as heart rate monitors, thermometers, and sensors. Due to very low power consumption, devices compliant with this standard can operate for several years on coin cell batteries without the need for recharging. This cutting-edge book helps you understand the whats , whys , and hows of Bluetooth LE. It includes a broad view of the technology, identifies the various building blocks, and explains how they come together. You also find discussions on Bluetooth basics, providing the background information needed to master Bluetooth LE.The book explains the architecture of Bluetooth LE stack and the functionality provided by each of the layers. You find expert guidance in setting up your own system in a quick and efficient manner with inexpensive, easily available hardware and just a couple of PCs running Linux. This unique volume features two chapters that are dedi...

  18. Investigations of electrical and optical properties of low energy ion irradiated α-Fe{sub 2}O{sub 3} (hematite) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sulania, Indra; Kanjilal, D. [Inter University Accelerator Centre, P O Box-10502, Aruna Asaf Ali Marg, New Delhi-110067 (India); Kaswan, Jyoti; Attatappa, Vinesh [Department of physics, Amity University, Manesar-122 413, Haryana (India); Karn, Ranjeet Kumar [Jamshedpur Cooperative College, Circuit House Area, Jamshedpur-831001, Jharkhand (India); Agarwal, D. C. [Sant Longowal Institute of Engineering and Technology, Sangrur, Longowal-148106, Punjab (India)

    2016-05-23

    Thin films of α-Fe{sub 2}O{sub 3} of thickness ~100 nm were synthesized on Si (100) and glass substrates by thermal evaporation method. The as deposited films were annealed at 400°C in Oxygen environment for 2 hours to obtain the desired phase. The annealed films found to be polycrystalline in nature with an average crystallite size ~7 nm. The direct and indirect band gaps were found to be 2.2 and 1.5 eV respectively for annealed films using. I-V characteristics and Hall-effect measurement of annealed films showed n-type semi conducting behavior. Further, films were irradiated with nitrogen ions of energy 10 keV at an ion fluence of 1×10{sup 18} ions/cm{sup 2}. After irradiation, a decrease in both direct as well as indirect band gap was observed, from 2.2 to 2.1 eV and 1.5 to 1.3 eV respectively. I-V characteristic and Hall-Effect measurement confirmed change in conductivity of the films from n-type to p-type after irradiation, which can have possible applications in semi conducting device fabrications.

  19. Parameter optimization for Doppler laser cooling of a low-energy heavy ion beam at the storage ring S-LSR

    Science.gov (United States)

    Osaki, Kazuya; Okamoto, Hiromi

    2014-05-01

    S-LSR is a compact ion storage ring constructed at Kyoto University several years ago. The ring is equipped with a Doppler laser cooling system aimed at beam crystallization. Bearing in mind hardware limitations in S-LSR, we try to find an optimum set of primary experimental parameters for the production of an ultracold heavy ion beam. Systematic molecular dynamics simulations are carried out for this purpose. It is concluded that the detuning and spot size of the cooling laser should be chosen around -42 MHz and 1.5 mm, respectively, for the most efficient cooling of 40 keV ^{24}Mg^+ beams in S-LSR. Under the optimum conditions, the use of the resonant coupling method followed by radio-frequency field ramping enables us to reach an extremely low beam temperature on the order of 0.1 K in the transverse degrees of freedom. The longitudinal degree of freedom can be cooled to close to the Doppler limit; i.e., to the mK range. We also numerically demonstrate that it is possible to establish a stable, long one-dimensionally ordered state of ions.

  20. Large scale and orientation-controllable nanotip structures on CuInS₂, Cu(In,Ga)S₂, CuInSe₂, and Cu(In,Ga)Se₂ by low energy ion beam bombardment process: growth and characterization.

    Science.gov (United States)

    Yen, Yu-Ting; Wang, Yi-Chung; Chen, Yu-Ze; Tsai, Hung-Wei; Hu, Fan; Lin, Shih-Ming; Chen, Yi-Ju; Lai, Chih-Chung; Liu, Wenlong; Wang, Tsang-Hsiu; Hong, Hwen-Fen; Chueh, Yu-Lun

    2014-06-11

    One-step facile methodology to create nanotip arrays on chalcopyrite materials (such as CuInS2, Cu(In,Ga)S2, CuInSe2, and Cu(In,Ga)Se2) via a low energy ion beam bombardment process has been demonstrated. The mechanism of formation for nanotip arrays has been proposed by sputtering yields of metals and reduction of metals induced by the ion beam bombardment process. The optical reflectance of these chalcopyrite nanotip arrays has been characterized by UV-vis spectrophotometer and the efficient light-trapping effect has been observed. Large scale (∼4'') and high density (10(10) tips/cm(2)) of chalcopyrite nanotip arrays have been obtained by using low ion energy (< 1 kV), short processing duration (< 30 min), and template-free. Besides, orientation and length of these chalcopyrite nanotip arrays are controllable. Our results can be the guide for other nanostructured materials fabrication by ion sputtering and are available for industrial production as well.

  1. MEIC Proton Beam Formation with a Low Energy Linac

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuhong [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The MEIC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low-energy protons and ions into the booster ring.

  2. D/sup -/ production by multiple charge-transfer collisions of low-energy D ions and atoms in cesium vapor

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, E.B. Jr.; Willmann, P.A.; Schlachter, A.S.

    1978-01-22

    The production of D/sup -/ by multiple charge-transfer collisions of a D/sup +/ beam in a cesium-vapor target is considered for D/sup +/ energies above 300 eV. The cross sections relevant to D/sup -/ formation are obtained by a least-squares fit of three-charge-state differential equations to experimental yield curves. Implications for production of intense negative-ion beams are discussed, and speculations are made about extrapolation to lower engeries.

  3. LINAC 3 experiment: This experiment is used to study some scenarios of the future LEIR (low-energy ion ring) vacuum design.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Photo 1 316LN stainless steel sheet 0.7 m thick sheet metal, with water-jet cut holes; before (sheet metal) and after rolling (tube). Photo 2 316LN stainless steel tube with water-jet cut holes. Photo 3 Inner tube is fitted with NEG (non-evaporable getter) strips, creating a kind of total NEG pump. Photo 4 Inner tube is fitted with NEG (non-evaporable getter) strips, creating a kind of total NEG pump. Photo 5 Same tubes but compiled on top of each other. Photo 6 The stack of tubes is put into a vacuum chamber that will be used in the LINAC 3 experiment during summer 2002 (lead-ion beam will be used for this experiment). The holes allow all-round pumping, i.e. close to the vacuum chamber walls.

  4. Evidence for site-specific intra-ionic hydrogen/deuterium exchange in the low-energy collision-induced dissociation product ion spectra of protonated small molecules generated by electrospray ionisation.

    Science.gov (United States)

    Holman, Stephen W; Wright, Patricia; Wells, Neil J; Langley, G John

    2010-04-01

    The experimental investigation of site-specific intra-ionic hydrogen/deuterium (H/D) exchange in the low-energy collision-induced dissociation (CID) product ion spectra of protonated small molecules generated by electrospray ionisation (ESI) is presented. The observation of intra-ionic H/D exchange in such ions under low-energy CID conditions has hitherto been rarely reported. The data suggest that the intra-ionic H/D exchange takes place in a site-specific manner between the ionising deuteron, localised at either a tertiary amine or a tertiary amine-N-oxide, and a gamma-hydrogen relative to the nitrogen atom. Nuclear magnetic resonance (NMR) spectroscopy measurements showed that no H/D exchange takes place in solution, indicating that the reaction occurs in the gas phase. The compounds analysed in this study suggested that electron-withdrawing groups bonded to the carbon atom bearing the gamma-hydrogen can preclude exchange. The effect of the electron-withdrawing group appears dependent upon its electronegativity, with lower chi value groups still allowing exchange to take place. However, the limited dataset available in this study prevented robust conclusions being drawn regarding the effect of the electron-withdrawing group. The observation of site-specific intra-ionic H/D exchange has application in the area of structural elucidation, where it could be used to introduce an isotopic label into the carbon skeleton of a molecule containing specific structural features. This could increase the throughput, and minimise the cost, of such studies due to the obviation of the need to produce a deuterium-labelled analogue by synthetic means. Copyright 2010 John Wiley & Sons, Ltd.

  5. Self-terminated etching of GaN with a high selectivity over AlGaN under inductively coupled Cl2/N2/O2 plasma with a low-energy ion bombardment

    Science.gov (United States)

    Zhong, Yaozong; Zhou, Yu; Gao, Hongwei; Dai, Shujun; He, Junlei; Feng, Meixin; Sun, Qian; Zhang, Jijun; Zhao, Yanfei; DingSun, An; Yang, Hui

    2017-10-01

    Etching of GaN/AlGaN heterostructure by O-containing inductively coupled Cl2/N2 plasma with a low-energy ion bombardment can be self-terminated at the surface of the AlGaN layer. The estimated etching rates of GaN and AlGaN were 42 and 0.6 nm/min, respectively, giving a selective etching ratio of 70:1. To study the mechanism of the etching self-termination, detailed characterization and analyses were carried out, including X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It was found that in the presence of oxygen, the top surface of the AlGaN layer was converted into a thin film of (Al,Ga)Ox with a high bonding energy, which effectively prevented the underlying atoms from a further etching, resulting in a nearly self-terminated etching. This technique enables a uniform and reproducible fabrication process for enhancement-mode high electron mobility transistors with a p-GaN gate.

  6. LENA: Low Energy Neutrino Astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Oberauer, L.; Hellgartner, D.; Lewke, T. [TU Muenchen, Physik-Department, James-Franck-Str. 1, 85748 Garching (Germany); Marrodan Undagoitia, T. [University of Zuerich, Physik Institut, Winterthurerstr. 190, CH-8057 Zuerich (Switzerland); Meindl, Q.; Moellenstedt, R.; Potzel, W.; Tippmann, M.; Feilitzsch, F. von; Winter, J.; Wurm, M. [TU Muenchen, Physik-Department, James-Franck-Str. 1, 85748 Garching (Germany)

    2011-08-15

    We focus on the physics potential of a large liquid scintillation detector in the field of low energy neutrino astrophysics. Proton decay search and long baseline oscillations will be discussed briefly at the end.

  7. FLSR - The Frankfurt low energy storage ring

    Science.gov (United States)

    Stiebing, K. E.; Alexandrov, V.; Dörner, R.; Enz, S.; Kazarinov, N. Yu.; Kruppi, T.; Schempp, A.; Schmidt Böcking, H.; Völp, M.; Ziel, P.; Dworak, M.; Dilfer, W.

    2010-02-01

    An electrostatic storage ring for low-energy ions with a design energy of 50 keV is presently being set up at the Institut für Kernphysik der Johann Wolfgang Goethe-Universität Frankfurt am Main, Germany (IKF). This new device will provide a basis for new experiments on the dynamics of ionic and molecular collisions, as well as for high precision and time resolved laser spectroscopy. In this article, the design parameters of this instrument are reported.

  8. Probe molecule chemisorption-low energy ion scattering study of surface active sites present in the orthorhombic Mo-V-(Te-Nb)-O catalysts for propane (amm)oxidation.

    Science.gov (United States)

    Guliants, Vadim V; Bhandari, Rishabh; Hughett, Andrew R; Bhatt, Salil; Schuler, Benjamin D; Brongersma, Hidde H; Knoester, Arie; Gaffney, Anne M; Han, Scott

    2006-03-30

    Methanol and allyl alcohol chemisorption and surface reaction in combination with low energy ion scattering (LEIS) were employed to determine the outermost surface compositions and chemical nature of active surface sites present on the orthorhombic (M1) Mo-V-O and Mo-V-Te-Nb-O phases. These orthorhombic phases exhibited vastly different behavior in propane (amm)oxidation reactions and, therefore, represented highly promising model systems for the study of the surface active sites. The LEIS data for the Mo-V-Te-Nb-O catalyst indicated surface depletion for V (-23%) and Mo (-27%), and enrichments for Nb (+55%) and Te (+165%) with respect to its bulk composition. Only minor changes in the topmost surface composition were observed for this catalyst under the conditions of the LEIS experiments at 400 degrees C, which is a typical temperature employed in these propane transformation reactions. These findings strongly suggested that the bulk orthorhombic Mo-V-Te-Nb-O structure may function as a support for the unique active and selective surface monolayer in propane (amm)oxidation. Moreover, direct evidence was obtained that the topmost surface VO(x) sites in the orthorhombic Mo-V-Te-Nb-O catalyst were preferentially covered by chemisorbed allyloxy species, whereas methanol was a significantly less discriminating probe molecule. The surface TeO(x) and NbO(x) sites on the Mo-V-Te-Nb-O catalyst were unable to chemisorb these probe molecules to the same extent as the VO(x) and MoO(x) sites. Our findings suggested that different surface locations for V(5+) ions in the orthorhombic Mo-V-O and Mo-V-Te-Nb-O catalysts may be primarily responsible for vastly different catalytic behavior exhibited by the Mo-V-O and Mo-V-Te-Nb-O phases. Although the proposed isolated V(5+) pentagonal bipyramidal sites in the orthorhombic Mo-V-O phase may be capable of converting propane to propylene with modest selectivity, the selective 8-electron transformation of propane to acrylic acid and

  9. Quantum scattering at low energies

    DEFF Research Database (Denmark)

    Derezinski, Jan; Skibsted, Erik

    2009-01-01

    For a class of negative slowly decaying potentials, including V(x):=−γ|x|−μ with 0quantum mechanical scattering theory in the low-energy regime. Using appropriate modifiers of the Isozaki–Kitada type we show that scattering theory is well behaved on the whole continuous spectrum...

  10. Quantum scattering at low energies

    DEFF Research Database (Denmark)

    Derezinski, Jan; Skibsted, Erik

    For a class of negative slowly decaying potentials, including with , we study the quantum mechanical scattering theory in the low-energy regime. Using modifiers of the Isozaki--Kitada type we show that scattering theory is well behaved on the {\\it whole} continuous spectrum of the Hamiltonian...

  11. Beam diagnostics for low energy beams

    Directory of Open Access Journals (Sweden)

    J. Harasimowicz

    2012-12-01

    Full Text Available Low-energetic ion and antimatter beams are very attractive for a number of fundamental studies. The diagnostics of such beams, however, is a challenge due to low currents down to only a few thousands of particles per second and significant fraction of energy loss in matter at keV beam energies. A modular set of particle detectors has been developed to suit the particular beam diagnostic needs of the ultralow-energy storage ring (USR at the future facility for low-energy antiproton and ion research, accommodating very low beam intensities at energies down to 20 keV. The detectors include beam-profile monitors based on scintillating screens and secondary electron emission, sensitive Faraday cups for absolute intensity measurements, and capacitive pickups for beam position monitoring. In this paper, the design of all detectors is presented in detail and results from beam measurements are shown. The resolution limits of all detectors are described and options for further improvement summarized. Whilst initially developed for the USR, the instrumentation described in this paper is also well suited for use in other low-intensity, low-energy accelerators, storage rings, and beam lines.

  12. Observations of orientation dependence of surface morphology in tungsten implanted by low energy and high flux D plasma

    DEFF Research Database (Denmark)

    Xu, H.Y.; Zhang, Yubin; Yuan, Y.

    2013-01-01

    〉 to the least in grains oriented close to 〈0 0 1〉. Three kinds of typical nanostructures were observed, with a clear dependence on grain orientation. Triangular structures were observed on grains oriented near the 〈1 1 1〉 corner of the inverse pole figure, with lamellar structures formed for grains oriented...

  13. A low energy solar town

    Energy Technology Data Exchange (ETDEWEB)

    Svendsen, Svend; Balocco, Carla

    1998-12-31

    The use of solar energy at large scale is necessary to support the energy savings and a more efficient energy use, like besides the quality of the ambient and the quality of the available energy sources. The solar heating systems with seasonal storage can be combined with heat from refuse incineration plants and other renewable heat sources. These systems combined with district heating are an example of the sustainable energy planning and the reduction of the environmental stress. Strategies for sustainability in the settlements can be defined by and energy model to planning that individuates development and economic and financial supports to. The aim of the work concerns the development of a small sun city with no use of fossil fuels. The new low energy solar town is an idealised urban an energy system. The studied settlement regards one thousand new low-energy houses supplied by a district heating with a central solar heating system with seasonal heat storage. The heating and ventilation demand in the studied low energy buildings are less than 40 kWh/m{sup 2}/year, the electricity demand is less than 2000 kWh per house year. The result of the work is an useful tool to the energy planning of the urban areas and it is also a necessary support to the political and energetic decisions. (EG) 58 refs.

  14. High flux expansion divertor studies in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V A; Maingi, R; Bell, R E; Gates, D A; Kaita, R; Kugel, H W; LeBlanc, B P; Maqueda, R; Menard, J E; Mueller, D; Paul, S F; Raman, R; Roquemore, A L

    2009-06-29

    Projections for high-performance H-mode scenarios in spherical torus (ST)-based devices assume low electron collisionality for increased efficiency of the neutral beam current drive. At lower collisionality (lower density), the mitigation techniques based on induced divertor volumetric power and momentum losses may not be capable of reducing heat and material erosion to acceptable levels in a compact ST divertor. Divertor geometry can also be used to reduce high peak heat and particle fluxes by flaring a scrape-off layer (SOL) flux tube at the divertor plate, and by optimizing the angle at which the flux tube intersects the divertor plate, or reduce heat flow to the divertor by increasing the length of the flux tube. The recently proposed advanced divertor concepts [1, 2] take advantage of these geometry effects. In a high triangularity ST plasma configuration, the magnetic flux expansion at the divertor strike point (SP) is inherently high, leading to a reduction of heat and particle fluxes and a facilitated access to the outer SP detachment, as has been demonstrated recently in NSTX [3]. The natural synergy of the highly-shaped high-performance ST plasmas with beneficial divertor properties motivated a further systematic study of the high flux expansion divertor. The National Spherical Torus Experiment (NSTX) is a mid-sized device with the aspect ratio A = 1.3-1.5 [4]. In NSTX, the graphite tile divertor has an open horizontal plate geometry. The divertor magnetic configuration geometry was systematically changed in an experiment by either (1) changing the distance between the lower divertor X-point and the divertor plate (X-point height h{sub X}), or by (2) keeping the X-point height constant and increasing the outer SP radius. An initial analysis of the former experiment is presented below. Since in the divertor the poloidal field B{sub {theta}} strength is proportional to h{sub X}, the X-point height variation changed the divertor plasma wetted area due to

  15. Low-energy mechanical ventilation

    DEFF Research Database (Denmark)

    Andersen, Claus Wessel; Hviid, Christian Anker

    2014-01-01

    and with as little energy consumption as 41.1 kWh/m2/year including heating and all building services with no use of renewable energy such as PVcells or solar heating. One of the key means of reaching the objectives was to implement mechanical ventilation with low pressure loss and therefore low energy consumption....... The project consists of two buildings, building one is 6 stories high, and building two is 4 stories high. The buildings have a gross area of 50,500 m2 including underground parking. The ventilation and indoor climate concept was to use mechanical ventilation together with mechanical cooling and fanassisted......, with an average of 1.1 kJ/m3. The yearly mean SFP based on estimated runtime is approx. 0.8 kJ/m3. The case shows the unlocked potential that lies within mechanical ventilation for nearzero energy consuming buildings....

  16. Low-energy electron potentiometry.

    Science.gov (United States)

    Jobst, Johannes; Kautz, Jaap; Mytiliniou, Maria; Tromp, Rudolf M; van der Molen, Sense Jan

    2017-10-01

    In a lot of systems, charge transport is governed by local features rather than being a global property as suggested by extracting a single resistance value. Consequently, techniques that resolve local structure in the electronic potential are crucial for a detailed understanding of electronic transport in realistic devices. Recently, we have introduced a new potentiometry method based on low-energy electron microscopy (LEEM) that utilizes characteristic features in the reflectivity spectra of layered materials [1]. Performing potentiometry experiments in LEEM has the advantage of being fast, offering a large field of view and the option to zoom in and out easily, and of being non-invasive compared to scanning-probe methods. However, not all materials show clear features in their reflectivity spectra. Here we, therefore, focus on a different version of low-energy electron potentiometry (LEEP) that uses the mirror mode transition, i.e. the drop in electron reflectivity around zero electron landing energy when they start to interact with the sample rather than being reflected in front of it. This transition is universal and sensitive to the local electrostatic surface potential (either workfunction or applied potential). It can consequently be used to perform LEEP experiments on a broader range of material compared to the method described in Ref[1]. We provide a detailed description of the experimental setup and demonstrate LEEP on workfunction-related intrinsic potential variations on the Si(111) surface and for a metal-semiconductor-metal junction with external bias applied. In the latter, we visualize the Schottky effect at the metal-semiconductor interface. Finally, we compare how robust the two LEEP techniques discussed above are against image distortions due to sample inhomogeneities or contamination. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. RHIC low-energy challenges and plans

    Energy Technology Data Exchange (ETDEWEB)

    Satogata,T.; Ahrens, L.; Bai, M.; Brennan, J.M.; Bruno, D.; Butler, J.; Drees, A.; Fedotov, A.; Fischer, W.; Harvey, M.; Hayes, T.; Jappe, W.; Lee, R.C.; MacKay, W.W.; Malitsky, N.; Marr, G.; Michnoff, R.; Oerter, B.; Pozdeyev, E.; Roser, T.; Schoefer, V.; Severino, F.; Smith, K.; Tepikian, S.; Tsoupas, N.

    2009-06-08

    Future Relativistic Heavy Ion Collider (RHIC) runs, including a portion of FY10 heavy ion operations, will explore collisions at center of mass energies of 5-50 GeV/n (GeV/nucleon). Operations at these energies is motivated by the search for a possible QCD phase transition critical point. The lowest end of this energy range is nearly a factor of four below the nominal RHIC injection center of mass energy {radical}s = 19.6 GeV/n. There are several operational challenges in the RHIC low-energy regime, including harmonic number changes, small longitudinal acceptance, lowered magnet field quality, nonlinear orbit control, and luminosity monitoring. We report on the experience with these challenges during beam tests with gold beams in March 2008. This includes first operations at {radical}s = 9.18 GeV/n, first beam experience at {radical}s = 5 GeV/n, and luminosity projections for near-term operations.

  18. Enhanced production of low energy electrons by alpha particle impact

    Science.gov (United States)

    Kim, Hong-Keun; Titze, Jasmin; Schöffler, Markus; Trinter, Florian; Waitz, Markus; Voigtsberger, Jörg; Sann, Hendrik; Meckel, Moritz; Stuck, Christian; Lenz, Ute; Odenweller, Matthias; Neumann, Nadine; Schössler, Sven; Ullmann-Pfleger, Klaus; Ulrich, Birte; Fraga, Rui Costa; Petridis, Nikos; Metz, Daniel; Jung, Annika; Grisenti, Robert; Czasch, Achim; Jagutzki, Ottmar; Schmidt, Lothar; Jahnke, Till; Schmidt-Böcking, Horst; Dörner, Reinhard

    2011-01-01

    Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion–atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He+ ions on isolated Ne atoms and on Ne dimers (Ne2). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation. PMID:21730184

  19. UE112_PGM-1: An open-port low-energy beamline at the BESSY II undulator UE112

    Directory of Open Access Journals (Sweden)

    Gregor Schiwietz

    2015-11-01

    Full Text Available The X-ray optical and mechanical designs of a low-energy high-flux VUV- to soft-X-ray beamline for photon energies between 17 and 200 eV (with lower flux up to 690 eV are presented.

  20. Status of the Frankfurt low energy electrostatic storage ring (FLSR)

    Science.gov (United States)

    King, F.; Kruppi, T.; Müller, J.; Dörner, R.; Schmidt, L. Ph H.; Schmidt-Böcking, H.; Stiebing, K. E.

    2015-11-01

    Frankfurt low-energy storage ring (FLSR) is an electrostatic storage ring for low-energy ions up to q · 80 keV (q being the ion charge state) at Institut für Kernphysik der Goethe-Universität, Frankfurt am Main, Germany. It has especially been designed to provide a basis for experiments on the dynamics of ionic and molecular collisions in complete kinematics, as well as for high precision and time resolved laser spectroscopy. The ring has ‘racetrack’ geometry with a circumference of 14.23 m. It comprises four experimental/diagnostic sections with regions of enhanced ion density (interaction regions). First beam has successfully been stored in FLSR in summer 2013. Since then the performance of the ring has continuously been improved and an electron target for experiments on dissociative recombination has been installed in one of the experimental sections.

  1. Towards Low Energy Atrial Defibrillation

    Directory of Open Access Journals (Sweden)

    Philip Walsh

    2015-09-01

    . Efficient transcutaneous power transfer and sensing of ICI during cardioversion are evidenced as key to the advancement of low-energy atrial defibrillation.

  2. Leptogenesis without CP Violation at Low Energies

    CERN Document Server

    Rebelo, Margarida N

    2003-01-01

    In this letter we give a class of examples where the decays of the heavy Majorana neutrinos may violate CP even if there is no CP violation at low energies, i. e., leptogenesis can take place without Majorana or Dirac type CP phases at low energies.

  3. Low-energy hot plasma and particles in Saturn's magnetosphere

    Science.gov (United States)

    Krimigis, S. M.; Bostrom, C. O.; Keath, E. P.; Carbary, J. F.; Roelof, E. C.; Armstrong, T. P.; Axford, W. I.; Gloeckler, G.; Hamilton, D. C.; Lanzerotti, L. J.

    1982-01-01

    Results of the low-energy charged particle experiment carried by Voyager 2 in the Saturn magnetosphere are presented. Measurements of ions of energy greater than 28 keV and electrons of energies greater than 22 keV revealed the presence of a region containing an extremely hot (30-50 keV) plasma extending from the orbit of Tethys past the orbit of Rhea, and a low-energy ion mantle inside the dayside and nightside magnetospheres. H, H2, H3, He, C and O at energies greater than 200 keV/n were found to be important constituents of the Saturn magnetosphere, at relative abundances suggestive of a solar wind origin. Low-energy electron flux enhancements were observed between the L shells of Rhea and Tethys which were absent during the Voyager 1 encounter, and persistent asymmetric electron pitch-angle distributions were noted in the outer magnetosphere in conjunction with the hot ion plasma torus. Signatures of the passage of Tethys and Enceladus through the magnetosphere were found, although not at the positions predicted by dipole magnetic field models.

  4. Use of a streamer chamber for low energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Van Bibber, K.; Pang, W.; Avery, M.; Bloemhof, E.

    1979-10-01

    A small streamer chamber has been implemented for low energy heavy ion reaction studies at the LBL 88-inch cyclotron. The response of the chamber to light and heavy ions below 35 MeV/nucleon has been examined. The limited sensitivity of light output as a function of ionization works to advantage in recording a wide variety of tracks in the same photograph whose energy loss may vary considerably. Furthermore, as gas targets are attractive for several reasons, we have investigated the suitability of Ar and Xe for use in streamer chambers.

  5. Low Energy Mission Planning Toolbox Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Low Energy Mission Planning Toolbox is designed to significantly reduce the resources and time spent on designing missions in multi-body gravitational...

  6. Low-energy Planetary Excavator (LPE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC is developing an innovative Low-energy Planetary Excavator (LPE) to excavate in situ regolith, ice-regolith mixes, and a variety of other geologic materials...

  7. Low-energy Planetary Excavator (LPE) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ORBITEC proposes to develop an innovative Low-energy Planetary Excavator (LPE) to excavate in situ regolith, ice-regolith mixes, and a variety of other geologic...

  8. Low Energy Electronics Design for Mobile Platforms

    National Research Council Canada - National Science Library

    East, J

    2002-01-01

    In order to address the need for low-energy electronics design for mobile platforms in future Army communication systems a multidisciplinary effort is needed to investigate system and component design...

  9. Exploring the Hidden Sector @ Low Energies

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Over the years we have accumulated a large number of indications for physics beyond the standard model. This new physics is often sought-after at high masses and energies. Here collider experiments can bring decisive insights. However, over recent years it has become increasingly clear that new physics can also appear at low energy, but extremely weak coupling. Experiments and observations at this `low energy frontier' therefore provide a powerful tool to gain insight into fundamental physics, which is complementary to accelerators.

  10. Characterisation of Redlen high-flux CdZnTe

    Science.gov (United States)

    Thomas, B.; Veale, M. C.; Wilson, M. D.; Seller, P.; Schneider, A.; Iniewski, K.

    2017-12-01

    CdZnTe is a promising material for the current generation of free electron laser light sources and future laser-driven γ-ray sources which require detectors capable of high flux imaging at X-ray and γ-ray energies (> 10 keV) . However, at high fluxes CdZnTe has been shown to polarise due to hole trapping, leading to poor performance. Novel Redlen CdZnTe material with improved hole transport properties has been designed for high flux applications. Small pixel CdZnTe detectors were fabricated by Redlen Technologies and flip-chip bonded to PIXIE ASICs. An XIA Digital Gamma Finder PIXIE-16 system was used to digitise each of the nine analogue signals with a timing resolution of 10 ns. Pulse shape analysis was used to extract the rise times and amplitude of signals. These were measured as a function of applied bias voltage and used to calculate the mobility (μ) and mobility-lifetime (μτ) of electrons and holes in the material for three identical detectors. The measured values of the transport properties of electrons in the high-flux-capable material was lower than previously reported for Redlen CdZnTe material (μeτe ~ 1 × 10‑3 cm2V‑1 and μe ~ 1000 cm2V‑1s‑1) while the hole transport properties were found to have improved (μhτh ~ 3 × 10‑4 cm2V‑1 and μh ~ 100 cm2V‑1s‑1).

  11. Deuterium retention in graphite exposed to high flux plasma at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rusinov, A., E-mail: rusinov.aleksandr@gmail.com [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Trifonov, N.; Gasparyan, Yu. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation); Khripunov, B., E-mail: boris@nfi.kiae.ru [National Research Center Kurchatov Institute, Academic Kurchatov sq., 1, 123098 Moscow (Russian Federation); Mayer, M.; Roth, J. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmanstr.2, D-85748 Garching (Germany); Pisarev, A. [Moscow Engineering and Physics Institute, Kashirskoe sh. 31, 115409 Moscow (Russian Federation)

    2011-10-01

    Deuterium trapping in graphite under high flux plasma exposure at high temperatures was studied. A target of MPG-8 fine grain graphite was exposed to plasma beam in LENTA device at zero potential. The average ion flux was of about 10{sup 21} D/m{sup 2} s with a maximum in the center. The temperature was 1473 K in the center and 873 K outside the beam spot. After irradiation, the target was sectioned along and across the surface and studied by SEM, NRA, and TDS. Deuterium profiles measured by NRA showed a peak close to the surface and long tails in the bulk. TDS of samples taken for the front and back sides of the target were very similar. It is suggested, that D retention at the plasma irradiation is mainly controlled by trapping from the gas phase, locally created in the graphite pores by plasma ions injection and subsequent flow of gas to the back side through internal porosity.

  12. RADIATION DOSIMETRY OF THE PRESSURE VESSEL INTERNALS OF THE HIGH FLUX BEAM REACTOR.

    Energy Technology Data Exchange (ETDEWEB)

    HOLDEN,N.E.; RECINIELLO,R.N.; HU,J.P.; RORER,D.C.

    2002-08-18

    In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, both measurements and calculations of the decay gamma-ray dose rate have been performed for the reactor pressure vessel and vessel internal structures which included the upper and lower thermal shields, the transition plate, and the control rod blades. The measurements were made using Red Perspex{trademark} polymethyl methacrylate high-level film dosimeters, a Radcal ''peanut'' ion chamber, and Eberline's high-range ion chamber. To compare with measured gamma-ray dose rate, the Monte Carlo MCNP code and geometric progressive Microshield code were used to model the gamma transport and dose buildup.

  13. DISCO: a low-energy multipurpose beamline at synchrotron SOLEIL.

    Science.gov (United States)

    Giuliani, Alexandre; Jamme, Frédéric; Rouam, Valérie; Wien, Frank; Giorgetta, Jean-Luc; Lagarde, Bruno; Chubar, Oleg; Bac, Stéphane; Yao, Isabelle; Rey, Solène; Herbeaux, Christian; Marlats, Jean-Louis; Zerbib, Daniel; Polack, François; Réfrégiers, Matthieu

    2009-11-01

    DISCO, a novel low-energy beamline covering the spectrum range from the VUV to the visible, has received its first photons at the French synchrotron SOLEIL. In this article the DISCO design and concept of three experimental stations serving research communities in biology and chemistry are described. Emphasis has been put on high flux generation and preservation of polarization at variable energy resolutions. The three experiments include a completely new approach for microscopy and atmospheric pressure experiments as well as a ;classical' synchrotron radiation circular dichroism station. Preliminary tests of the optical design and technical concept have been made. Theoretical predictions of the beam have been compared with the first images produced by the first photons originating from the large-aperture bending-magnet source. Results are also reported concerning the cold finger used to absorb hard X-ray radiation in the central part of the synchrotron beam and to avoid heavy thermal load on the following optics. Wavelength selection using monochromators with different gratings for each experimental set-up as well as beam propagation and conditioning throughout the optical system are detailed. First photons comply very well with the theoretical calculations.

  14. Low energy fractures of the acetabulum.

    Science.gov (United States)

    Papadakos, N; Pearce, R; Bircher, M D

    2014-05-01

    Acetabular fractures due to high energy injuries are common and well documented; those secondary to low energy mechanisms are less well described. We undertook a retrospective study of the acetabular fracture referrals to our unit to evaluate the proportion of injuries resulting from a low energy mechanism. A total of 573 acetabular fractures were evaluated from 1 January 2005 to 31 December 2008. The plain radiography and computed tomography of those sustaining a low energy fracture were assessed and the fracture patterns classified. Of the 573 acetabular fractures, 71 (12.4%) were recorded as being a result of a low energy mechanism. The male-to-female ratio was 2.4:1 and the mean patient age was 67.0 years (standard deviation: 19.1 years). There was a significantly higher number of fractures (pfracture studies. Our results demonstrate that low energy fractures make up a considerable proportion of acetabular fractures with a distinctly different fracture pattern distribution. With the continued predicted rise in the incidence of osteoporosis, life expectancy and an aging population, it is likely that this type of fracture will become increasingly more common, posing difficult management decisions and leading to procedures that are technically more challenging.

  15. Formation of a high intensity low energy positron string

    Science.gov (United States)

    Donets, E. D.; Donets, E. E.; Syresin, E. M.; Itahashi, T.; Dubinov, A. E.

    2004-05-01

    The possibility of a high intensity low energy positron beam production is discussed. The proposed Positron String Trap (PST) is based on the principles and technology of the Electron String Ion Source (ESIS) developed in JINR during the last decade. A linear version of ESIS has been used successfully for the production of intense highly charged ion beams of various elements. Now the Tubular Electron String Ion Source (TESIS) concept is under study and this opens really new promising possibilities in physics and technology. In this report, we discuss the application of the tubular-type trap for the storage of positrons cooled to the cryogenic temperatures of 0.05 meV. It is intended that the positron flux at the energy of 1-5 eV, produced by the external source, is injected into the Tubular Positron Trap which has a similar construction as the TESIS. Then the low energy positrons are captured in the PST Penning trap and are cooled down because of their synchrotron radiation in the strong (5-10 T) applied magnetic field. It is expected that the proposed PST should permit storing and cooling to cryogenic temperature of up to 5×109 positrons. The accumulated cooled positrons can be used further for various physics applications, for example, antihydrogen production.

  16. Dosimetry of Low-Energy Beta Radiation

    DEFF Research Database (Denmark)

    Borg, Jette

    Useful techniques and procedures for derermination of absorbed doses from exposure in a low-energy beta radiation were studied and evaluated. The four techniques included were beta spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical...... low-energy beta radiation field a moderated spectrum from a carbon-14 source was used. The measured responce of a Si(Li) detector to photons (bremsstrahlung) showed fine agreemant with the MC calculated photon response, whereas the difference between measured and MC calculated response to electrons...

  17. Instrumentation in small low energy machines

    CERN Document Server

    Raich, U

    2005-01-01

    Low energy particle accelerators are used either as injectors for higher energy machines or as dedicated machines for special purposes. These may be industrial, medical or prototype machines for testing new accelerating schemes. Low energy beams open measurement possibilities not available at higher energies due to the low magnetic rigidity of the particles, due to their small penetration depth and due to rather big beam spot sizes. On the other hand these beams also represent special challenges due to their high energy deposition in matter, space charge problems etc. which are not seen at higher energies. Measurement principles typical for small accelerators will be presented and explained with the help of example implementations.

  18. Low Energy Lorentz Violation from Modified Dispersion at High Energies.

    Science.gov (United States)

    Husain, Viqar; Louko, Jorma

    2016-02-12

    Many quantum theories of gravity propose Lorentz-violating dispersion relations of the form ω=|k|f(|k|/M⋆), with recovery of approximate Lorentz invariance at energy scales much below M⋆. We show that a quantum field with this dispersion predicts drastic low energy Lorentz violation in atoms modeled as Unruh-DeWitt detectors, for any f that dips below unity somewhere. As an example, we show that polymer quantization motivated by loop quantum gravity predicts such Lorentz violation below current ion collider rapidities.

  19. Detectors for low energy electron cooling in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Carlier, F. S. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-02-15

    Low-energy operation of RHIC is of particular interest to study the location of a possible critical point in the QCD phase diagram. The performance of RHIC at energies equal to or lower than 10 GV/nucleon is limited by nonlinearities, Intra-BeamScattering (IBS) processes and space-charge effects. To successfully address the luminosity and ion store lifetime limitations imposed by IBS, the method of electron cooling has been envisaged. During electron cooling processes electrons are injected along with the ion beam at the nominal ion bunch velocities. The velocity spread of the ion beam is reduced in all planes through Coulomb interactions between the cold electron beam and the ion beam. The electron cooling system proposed for RHIC will be the first of its kind to use bunched beams for the delivery of the electron bunches, and will therefore be accompanied by the necessary challenges. The designed electron cooler will be located in IP2. The electron bunches will be accelerated by a linac before being injected along side the ion beams. Thirty consecutive electron bunches will be injected to overlap with a single ion bunch. They will first cool the yellow beam before being extracted, turned by 180-degrees, and reinjected into the blue beam for cooling. As such, both the yellow and blue beams will be cooled by the same ion bunches. This will pose considerable challenges to ensure proper electron beam quality to cool the second ion beam. Furthermore, no ondulator will be used in the electron cooler so radiative recombination between the ions and the electrons will occur.

  20. High-flux solar photon processes: Opportunities for applications

    Energy Technology Data Exchange (ETDEWEB)

    Steinfeld, J.I.; Coy, S.L.; Herzog, H.; Shorter, J.A.; Schlamp, M.; Tester, J.W.; Peters, W.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1992-06-01

    The overall goal of this study was to identify new high-flux solar photon (HFSP) processes that show promise of being feasible and in the national interest. Electric power generation and hazardous waste destruction were excluded from this study at sponsor request. Our overall conclusion is that there is promise for new applications of concentrated solar photons, especially in certain aspects of materials processing and premium materials synthesis. Evaluation of the full potential of these and other possible applications, including opportunities for commercialization, requires further research and testing. 100 refs.

  1. Electron cooling for low-energy RHIC program

    Energy Technology Data Exchange (ETDEWEB)

    Fedotov, A.; Ben-Zvi, I.; Chang, X.; Kayran, D.; Litvinenko, V.N.; Pendzick, A.; Satogata, T.

    2009-08-31

    Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beam energies below 10 GeV/nucleon. Providing collisions at such energies, termed RHIC 'low-energy' operation, will help to answer one of the key questions in the field of QCD about existence and location of critical point on the QCD phase diagram. The electron cooling system should deliver electron beam of required good quality over energies of 0.9-5 MeV. Several approaches to provide such cooling were considered. The baseline approach was chosen and design work started. Here we describe the main features of the cooling system and its expected performance. We have started design work on a low-energy RHIC electron cooler which will operate with kinetic electron energy range 0.86-2.8 (4.9) MeV. Several approaches to an electron cooling system in this energy range are being investigated. At present, our preferred scheme is to transfer the Fermilab Pelletron to BNL after Tevatron shutdown, and to use it for DC non-magnetized cooling in RHIC. Such electron cooling system can significantly increase RHIC luminosities at low-energy operation.

  2. Low energy analysis techniques for CUORE

    Science.gov (United States)

    Alduino, C.; Alfonso, K.; Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Bari, G.; Beeman, J. W.; Bellini, F.; Benato, G.; Bersani, A.; Biassoni, M.; Branca, A.; Brofferio, C.; Bucci, C.; Camacho, A.; Caminata, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Cappelli, L.; Cardani, L.; Carniti, P.; Casali, N.; Cassina, L.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Cushman, J. S.; D'Addabbo, A.; D'Aguanno, D.; Dafinei, I.; Davis, C. J.; Dell'Oro, S.; Deninno, M. M.; Di Domizio, S.; Di Vacri, M. L.; Drobizhev, A.; Fang, D. Q.; Faverzani, M.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Gladstone, L.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Hansen, E.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Keppel, G.; Kolomensky, Yu. G.; Leder, A.; Ligi, C.; Lim, K. E.; Ma, Y. G.; Maino, M.; Marini, L.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Mosteiro, P. J.; Napolitano, T.; Nastasi, M.; Nones, C.; Norman, E. B.; Novati, V.; Nucciotti, A.; O'Donnell, T.; Ouellet, J. L.; Pagliarone, C. E.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pessina, G.; Piperno, G.; Pira, C.; Pirro, S.; Pozzi, S.; Previtali, E.; Rosenfeld, C.; Rusconi, C.; Sakai, M.; Sangiorgio, S.; Santone, D.; Schmidt, B.; Schmidt, J.; Scielzo, N. D.; Singh, V.; Sisti, M.; Smith, A. R.; Taffarello, L.; Terranova, F.; Tomei, C.; Vignati, M.; Wagaarachchi, S. L.; Wang, B. S.; Wang, H. W.; Welliver, B.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zhang, G. Q.; Zimmermann, S.; Zucchelli, S.

    2017-12-01

    CUORE is a tonne-scale cryogenic detector operating at the Laboratori Nazionali del Gran Sasso (LNGS) that uses tellurium dioxide bolometers to search for neutrinoless double-beta decay of ^{130}Te. CUORE is also suitable to search for low energy rare events such as solar axions or WIMP scattering, thanks to its ultra-low background and large target mass. However, to conduct such sensitive searches requires improving the energy threshold to 10 keV. In this paper, we describe the analysis techniques developed for the low energy analysis of CUORE-like detectors, using the data acquired from November 2013 to March 2015 by CUORE-0, a single-tower prototype designed to validate the assembly procedure and new cleaning techniques of CUORE. We explain the energy threshold optimization, continuous monitoring of the trigger efficiency, data and event selection, and energy calibration at low energies in detail. We also present the low energy background spectrum of CUORE-0 below 60 keV. Finally, we report the sensitivity of CUORE to WIMP annual modulation using the CUORE-0 energy threshold and background, as well as an estimate of the uncertainty on the nuclear quenching factor from nuclear recoils inCUORE-0.

  3. Parity violation in low-energy

    Energy Technology Data Exchange (ETDEWEB)

    Martin Savage

    2001-12-01

    Parity violation in low-energy nuclear observables is included in the pionless effective field theory. The model-independent relation between the parity-violating asymmetry in polarized np -> d gamma and the non-nucleon part of the deuteron anapole moment is discussed. The asymmetry in np -> d gamma computed with KSW power-counting, and recently criticized by Desplanques, is discussed.

  4. Low energy observables with the ATLAS experiment

    CERN Document Server

    Foster, Andrew Geoffrey; The ATLAS collaboration

    2017-01-01

    Recent results in the soft QCD sector of the Standard Model are presented. Measurements of low energy observables were performed with the ATLAS detector at the Large Hadron Collider at CERN. In particular, underlying event, charged particle correlation and diffraction observables are reported and various models of Monte Carlo predictions are compared to the data.

  5. Study on low-energy positron polarimetry

    Indian Academy of Sciences (India)

    A polarised positron source has been proposed for the design of the international linear collider (ILC). In order to optimise the positron beam, a measurement of its degree of polarisation close to the positron creation point is desired. In this contribution, methods for determining the positron polarisation at low energies are ...

  6. Architectural Quality of Low Energy Houses

    DEFF Research Database (Denmark)

    Lauring, Michael; Marsh, Rob

    2008-01-01

    This paper expounds a systematic vocabulary concerning architectural quality in houses in general and low energy houses in particular. The vocabulary consists of nine themes. Inside each theme, examples are given of how to achieve both architectural quality and good environmental performance...

  7. Low-energy beam line at KVI

    NARCIS (Netherlands)

    Toprek, D.; Formanoy, I.; Brandenburg, S.

    2006-01-01

    This paper describes the redesign of the low-energy beam line at KVI. Redesigned and properties of the optical elements of the transport beam line is done by using the code COSY INFINITY in the third-order of approximation. The effects of fringe fields of the optical elements are also taken into

  8. The High Flux Beam Reactor at Brookhaven National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, S.M.

    1994-12-31

    Brookhaven National Laboratory`s High Flux Beam Reactor (HFBR) was built because of the need of the scientist to always want `more`. In the mid-50`s the Brookhaven Graphite reactor was churning away producing a number of new results when the current generation of scientists, led by Donald Hughes, realized the need for a high flux reactor and started down the political, scientific and engineering path that led to the BFBR. The effort was joined by a number of engineers and scientists among them, Chemick, Hastings, Kouts, and Hendrie, who came up with the novel design of the HFBR. The two innovative features that have been incorporated in nearly all other research reactors built since are: (i) an under moderated core arrangement which enables the thermal flux to peak outside the core region where beam tubes can be placed, and (ii) beam tubes that are tangential to the core which decrease the fast neutron background without affecting the thermal beam intensity. Construction began in the fall of 1961 and four years later, at a cost of $12 Million, criticality was achieved on Halloween Night, 1965. Thus began 30 years of scientific accomplishments.

  9. Very high flux research reactors based on particle fuels

    Energy Technology Data Exchange (ETDEWEB)

    Powell, J.R.; Takahashi, H.

    1985-01-01

    A new approach to high flux research reactors is described, the VHFR (Very High Flux Reactor). The VHFR fuel region(s) are packed beds of HTGR-type fuel particles through which coolant (e.g., D/sub 2/O) flows directly. The small particle diameter (typically on the order of 500 microns) results in very large surface areas for heat transfer (approx. 100 cm/sup 2//cm/sup 3/ of bed), high power densities (approx. 10 megawatts per liter), and minimal ..delta..T between fuel and coolant (approx. 10 K) VHFR designs are presented which achieve steady-state fluxes of approx. 2x10/sup 16/ n/cm/sup 2/sec. Deuterium/beryllium combinations give the highest flux levels. Critical mass is low, approx. 2 kg /sup 235/U for 20% enriched fuel. Refueling can be carried out continuously on-line, or in a batch process with a short daily shutdown. Fission product inventory is very low, approx. 100 to 300 grams, depending on design.

  10. Reduction of thermal conductivity by low energy multi-Einstein optic modes

    Directory of Open Access Journals (Sweden)

    Huili Liu

    2016-06-01

    Full Text Available The lattice dynamics and thermal transport in Cu2-δSe compounds were investigated via theoretical calculations, neutron measurement, and characterization of thermal properties. The results show that binary ordered Cu2-δSe has an extremely low lattice thermal conductivity at low temperatures. The low energy multi-Einstein optic modes are the dominant approach obtaining such an extremely low lattice thermal conductivity. It is indicated that the damped vibrations of copper ions could contribute to the low energy multi-Einstein optic modes, especially for those low energy branches at 2–4 meV.

  11. Low Energy Electrons in the Mars Plasma Environment

    Science.gov (United States)

    Link, Richard

    2001-05-01

    The ionosphere of Mars is rather poorly understood. The only direct measurements were performed by the Viking 1 and 2 landers in 1976, both of which carried a Retarding Potential Analyzer. The RPA was designed to measure ion properties during the descent, although electron fluxes were estimated from changes in the ion currents. Using these derived low-energy electron fluxes, Mantas and Hanson studied the photoelectron and the solar wind electron interactions with the atmosphere and ionosphere of Mars. Unanswered questions remain regarding the origin of the low-energy electron fluxes in the vicinity of the Mars plasma boundary. Crider, in an analysis of Mars Global Surveyor Magnetometer/Electron Reflectometer measurements, has attributed the formation of the magnetic pile-up boundary to electron impact ionization of exospheric neutral species by solar wind electrons. However, the role of photoelectrons escaping from the lower ionosphere was not determined. In the proposed work, we will examine the role of solar wind and ionospheric photoelectrons in producing ionization in the upper ionosphere of Mars. Low-energy (< 4 keV) electrons will be modeled using the two-stream electron transport code of Link. The code models both external (solar wind) and internal (photoelectron) sources of ionization, and accounts for Auger electron production. The code will be used to analyze Mars Global Surveyor measurements of solar wind and photoelectrons down to altitudes below 200 km in the Mars ionosphere, in order to determine the relative roles of solar wind and escaping photoelectrons in maintaining plasma densities in the region of the Mars plasma boundary.

  12. Low Energy Electrons in the Mars Plasma Environment

    Science.gov (United States)

    Link, Richard

    2001-01-01

    The ionosphere of Mars is rather poorly understood. The only direct measurements were performed by the Viking 1 and 2 landers in 1976, both of which carried a Retarding Potential Analyzer. The RPA was designed to measure ion properties during the descent, although electron fluxes were estimated from changes in the ion currents. Using these derived low-energy electron fluxes, Mantas and Hanson studied the photoelectron and the solar wind electron interactions with the atmosphere and ionosphere of Mars. Unanswered questions remain regarding the origin of the low-energy electron fluxes in the vicinity of the Mars plasma boundary. Crider, in an analysis of Mars Global Surveyor Magnetometer/Electron Reflectometer measurements, has attributed the formation of the magnetic pile-up boundary to electron impact ionization of exospheric neutral species by solar wind electrons. However, the role of photoelectrons escaping from the lower ionosphere was not determined. In the proposed work, we will examine the role of solar wind and ionospheric photoelectrons in producing ionization in the upper ionosphere of Mars. Low-energy (electrons will be modeled using the two-stream electron transport code of Link. The code models both external (solar wind) and internal (photoelectron) sources of ionization, and accounts for Auger electron production. The code will be used to analyze Mars Global Surveyor measurements of solar wind and photoelectrons down to altitudes below 200 km in the Mars ionosphere, in order to determine the relative roles of solar wind and escaping photoelectrons in maintaining plasma densities in the region of the Mars plasma boundary.

  13. Further evidence for low-energy protonium production in vacuum

    CERN Document Server

    Lodi Rizzini, E; Zurlo, N; Charlton, M; Amsler, C; Bonomi, G; Canali, C; Carraro, C; Fontana, A; Genova, P; Hayano, R; Jorgensen, L V; Kellerbauer, A; Lagomarsino, V; Landua, R; Macri, M; Manuzio, G; Montagna, P; Regenfus, C; Rotondi, A; Testera, G; Variola, A; van der Werf, D P

    2012-01-01

    We describe an experiment performed in the ATHENA apparatus in which there is evidence that the antiproton-proton bound state, protonium, has been produced at very low energies in vacuum following the interaction of cold antiprotons with a trapped cloud of molecular hydrogen ions. The latter were confined in a centrifugally separated belt outside a positron plasma used for antihydrogen formation. Studies have been performed at low positron plasma temperatures in which the protonium annihilation signal has been identified along with that from antihydrogen, and we discuss how their contributions can be disentangled. With the positron plasma heated to around 10000 K the ions become distributed in the positrons, and the majority of the annihilation signal can be explained in terms of protonium formation, as antihydrogen creation is heavily suppressed. In this case we compare the observed protonium formation rate with expectations from theory and find reasonable accord, when experimental systematics are taken into...

  14. Further Evidence for Low Energy Protonium Production in Vacuum

    CERN Document Server

    Lodi Rizzini, Evandro; Zurlo, Nicola; Charlton, Michael; Amsler, Claude,; Bonomi, Germano; Canali, Carlo; Carraro, Carlo; Fontana, Andrea; Genova, Pablo; Hayano, Ryugo; Jorgensen, Lars Varming; Kellerbauer, Alban; Lagomarsino, Vittorio; Landua, R; Macrì, Mario; Manuzio, Giulio; Montagna, Paolo; Regenfus, Christian; Rotondi, Alberto; Testera, Gemma; Variola, Alessandro; van der Werf, Dirk Peter

    2012-01-01

    We describe an experiment performed in the ATHENA apparatus in which there is evidence that the antiproton-proton bound state, protonium, has been produced at very low energies in vacuum following the interaction of cold antiprotons with a trapped cloud of molecular hydrogen ions. The latter were confined in a centrifugally separated belt outside a positron plasma used for antihydrogen formation. Studies have been performed at low positron plasma temperatures in which the protonium annihilation signal has been identified along with that from antihydrogen, and we discuss how their contributions can be disentangled. With the positron plasma heated to around 10,000 K the ions become distributed in the positrons, and the majority of the annihilation signal can be explained in terms of protonium formationion, as antihydrogen creation is heavily suppressed. In this case we compare the observed protonium formation rate with expectations from theory and find reasonable accord, when experimental systematics are taken...

  15. Study of silicon damage caused by ultra-low energy boron implantation

    CERN Document Server

    Zhang, S

    2001-01-01

    Ultra-shallow junction formation in deep submicron Si devices is limited by anomalous diffusion of the dopant, which is related to the release of interstitials from defect clusters formed during the implantation of energetic ions or the subsequent annealing. The work described in this dissertation is concerned with the effects of low energy B ion implantation, especially damage formation, clustering and its annealing. After a review of the stopping and ranges of energetic ions in Si, the formation of implant damage, in particular of point defects, their migration, agglomeration and annihilation, including the involvement of dopant ions, is considered. A description of the Salford ultra low energy implanter is given and the main analysis technique, medium ion energy scattering (MEIS) reviewed. Additional analytical techniques used, such as secondary ion mass spectrometry (SIMS), 4-point probe and cross section transmission microscopy (XTEM) as well as TRIM simulation are briefly described. MEIS has been used t...

  16. Dialyzer Reuse and Outcomes of High Flux Dialysis.

    Science.gov (United States)

    Argyropoulos, Christos; Roumelioti, Maria-Eleni; Sattar, Abdus; Kellum, John A; Weissfeld, Lisa; Unruh, Mark L

    2015-01-01

    The bulk of randomized trial evidence for the expanding use of High Flux (HF) hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO) allowed, while the other (Membrane Outcomes Permeability, MPO) excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF) dialyzers. Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M) concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO. In HEMO, minimally reused (dialysis and the reuse process on dialyzers may suggest novel biomarkers for uremic toxicity and may accelerate membrane technology innovations that will improve patient outcomes.

  17. Enhancement mechanisms of low energy nuclear reactions

    Energy Technology Data Exchange (ETDEWEB)

    Gareev, F. A.; Zhidkova, I.E.; Ratis, Yu.L. [Joint Institute for Nuclear Research, JINR, 6 Joliot Curie Street, Dubna, Moscow Region 141980 (Russian Federation)

    2006-07-01

    The full review of Russian low energy nuclear reactors is represented. We have concluded that transmutation of nuclei at low energies, LENR, is possible in the framework of the modern physical theory - excitation and ionization of atoms and universal resonance synchronization principle are responsible for it. Investigation of this phenomenon requires knowledge of different branches of science: nuclear and atomic physics, chemistry and electrochemistry, condensed matter and solid state physics. The results of this research field can provide a new source of energy, substances and technologies. The puzzle of poor reproducibility of experimental data is due to the fact that LENR occurs in open systems and it is extremely sensitive to parameters of external fields and systems. Classical reproducibility principle should be reconsidered for LENR experiments. Poor reproducibility and unexplained results do not means that the experiment is wrong.

  18. Entanglement creation in low-energy scattering

    Energy Technology Data Exchange (ETDEWEB)

    Weder, Ricardo [Institut National de Recherche en Informatique et en Automatique Paris-Rocquencourt, Projet POEMS, Domaine de Voluceau-Rocquencourt, BP 105, F-78153, Le Chesnay Cedex (France)

    2011-12-15

    We study the entanglement creation in the low-energy scattering of two particles in three dimensions, for a general class of interaction potentials that are not required to be spherically symmetric. The incoming asymptotic state, before the collision, is a product of two normalized Gaussian states. After the scattering, the particles are entangled. We take as a measure of the entanglement the purity of one of them. We provide a rigorous explicit computation, with error bound, of the leading order of the purity at low energy. The entanglement depends strongly on the difference of the masses. It takes its minimum when the masses are equal, and it increases rapidly with the difference of the masses. It is quite remarkable that the anisotropy of the potential gives no contribution to the leading order of the purity, in spite of the fact that entanglement is a second-order effect.

  19. Gas Electron multipliers for low energy beams

    CERN Document Server

    Arnold, F; Ropelewski, L; Spanggaard, J; Tranquille, G

    2010-01-01

    Gas Electron Multipliers (GEM) find their way to more and more applications in beam instrumentation. Gas Electron Multiplication uses a very similar physical phenomenon to that of Multi Wire Proportional Chambers (MWPC) but for small profile monitors they are much more cost efficient both to produce and to maintain. This paper presents the new GEM profile monitors intended to replace the MWPCs currently used at CERN’s low energy Antiproton Decelerator (AD). It will be shown how GEMs overcome the documented problems of profile measurements with MWPCs for low energy beams, where the interaction of the beam with the detector has a large influence on the measured profile. Results will be shown of profile measurements performed at 5 MeV using four different GEM prototypes, with discussion on the possible use of GEMs at even lower energies needed at the AD in 2013.

  20. PHENIX plans for RHIC low energy run

    CERN Document Server

    Sakaguchi, Takao

    2009-01-01

    PHENIX plans for low energy running are presented. Current detector setting makes it possible to measure dielectron spectra down to sqrt(s_NN)=39GeV, and photon/high pT hadron spectra down to below sub-injection energy (sqrt(s_NN)=5-10GeV). The upgrade of the trigger scheme after the installation of VTX detector will enable PHENIX to fully explore the sub-injection energy regime, starting 2011.

  1. PHYSICS WITH ULTRA-LOW ENERGY ANTIPROTONS

    Energy Technology Data Exchange (ETDEWEB)

    M. HOLZSCHEITER

    2001-02-01

    In this report the author describes the current status of the antiproton deceleration (AD) facility at CERN, and highlights the physics program with ultra-low energy antiproton at this installation. He also comments on future possibilities provided higher intensity antiproton beams become available at Fermilab, and review possibilities for initial experiments using direct degrading of high energy antiprotons in material has been developed and proven at CERN.

  2. Targeting Low-Energy Ballistic Lunar Transfers

    Science.gov (United States)

    Parker, Jeffrey S.

    2010-01-01

    Numerous low-energy ballistic transfers exist between the Earth and Moon that require less fuel than conventional transfers, but require three or more months of transfer time. An entirely ballistic lunar transfer departs the Earth from a particular declination at some time in order to arrive at the Moon at a given time along a desirable approach. Maneuvers may be added to the trajectory in order to adjust the Earth departure to meet mission requirements. In this paper, we characterize the (Delta)V cost required to adjust a low-energy ballistic lunar transfer such that a spacecraft may depart the Earth at a desirable declination, e.g., 28.5(white bullet), on a designated date. This study identifies the optimal locations to place one or two maneuvers along a transfer to minimize the (Delta)V cost of the transfer. One practical application of this study is to characterize the launch period for a mission that aims to launch from a particular launch site, such as Cape Canaveral, Florida, and arrive at a particular orbit at the Moon on a given date using a three-month low-energy transfer.

  3. Spontaneous Pattern Formation on Ion Bombarded Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Chason, Eric; Erlebacher, Jonah, Aziz, Michael J.; Floro, Jerrold A.; Sinclair, Michael B.

    1999-04-26

    Pattern formation on surfaces undergoing low-energy ion bombardment is a common phenomenon. Here, a recently developed in situ spectroscopic light scattering technique was used to monitor periodic ripple evolution on Si(001) during Ar(+) sputtering. Analysis of the rippling kinetics indicated that under high flux sputtering at low temperatures the concentration of mobile species on the surface is saturated, and, surprisingly, is both temperature and ion flux independent. This is due to an effect of ion collision cascades on the concentration of mobile species. This new understanding of surface dynamics during sputtering allowed us to measure straighforwardly the activation energy for atomic migration on the surface to be 1.2+0.1 eV. The technique is generalizable to any material, including high temperature and insulating materials for which surface migration energies are notoriously difficult to measure.

  4. Corrosion behavior of low energy, high temperature nitrogen ion ...

    Indian Academy of Sciences (India)

    Plasma Physics Research Center, Science and Research Campus of Islamic Azad University, P.O. Box 14665-678, Tehran, Iran; Center of Nuclear Agriculture and Medicine Research, Atomic Energy organization, Karj; Department of Physics, Sharif University, Tehran, Iran; Department of Physics University of Tehran, ...

  5. Heliosphere Instrument for Spectra, Composition and Anisotropy at Low Energies

    Science.gov (United States)

    Lanzerotti, L. J.; Gold, R. E.; Anderson, K. A.; Armstrong, T. P.; Lin, R. P.; Krimigis, S. M.; Pick, M.; Roelof, E. C.; Sarris, E. T.; Simnett, G. M.

    1992-01-01

    The Heliosphere Instrument for Spectra, Composition, and Anisotropy at Low Energies (HI-SCALE) is designed to make measurements of interplanetary ions and electrons throughout the entire Ulysses mission. The ions (E(i) greater than about 50 keV) and electrons (E(e) greater than about 30 keV) are identified uniquely and detected by five separate solid-state detector telescopes that are oriented to give nearly complete pitch-angle coverage from the spinning spacecraft. Ion elemental abundances are determined by Delta E vs E telescope using a thin (5 microns) front solid state detector element in a three-element telescope. Experimental operation is controlled by a microprocessor-based data system. Inflight calibration is provided by radioactive sources mounted on telescope covers which can be closed for calibration purposes and for radiation protection during the course of the mission. Ion and electron spectral information is determined using both broad-energy-range rate channels and a 32 channel pulse-height analyzer for more detailed spectra. Some initial in-ecliptic measurements are presented which demonstrate the features of the instrument.

  6. Low energy intake plus low energy expenditure (low energy flux), not energy surfeit, predicts future body fat gain.

    Science.gov (United States)

    Hume, David John; Yokum, Sonja; Stice, Eric

    2016-06-01

    There is a paucity of studies that have prospectively tested the energy surfeit theory of obesity with the use of objectively estimated energy intake and energy expenditure in humans. An alternative theory is that homeostatic regulation of body weight is more effective when energy intake and expenditure are both high (high energy flux), implying that low energy flux should predict weight gain. We aimed to examine the predictive relations of energy balance and energy flux to future weight gain and tested whether results were replicable in 2 independent samples. Adolescents (n = 154) and college-aged women (n = 75) underwent 2-wk objective doubly labeled water, resting metabolic rate, and percentage of body fat measures at baseline. Percentage of body fat was measured annually for 3 y of follow-up for the adolescent sample and for 2 y of follow-up for the young adult sample. Low energy flux, but not energy surfeit, predicted future increases in body fat in both studies. Furthermore, high energy flux appeared to prevent fat gain in part because it was associated with a higher resting metabolic rate. Counter to the energy surfeit model of obesity, results suggest that increasing energy expenditure may be more effective for reducing body fat than caloric restriction, which is currently the treatment of choice for obesity. This trial was registered at clinicaltrials.gov as NCT02084836. © 2016 American Society for Nutrition.

  7. Dosimetry of low-energy beta radiation

    Energy Technology Data Exchange (ETDEWEB)

    Borg, J.

    1996-08-01

    Useful techniques and procedures for determination of absorbed doses from exposure in a low-energy {beta} radiation field were studied and evaluated in this project. The four different techniques included were {beta} spectrometry, extrapolation chamber dosimetry, Monte Carlo (MC) calculations, and exoelectron dosimetry. As a typical low-energy {beta} radiation field a moderated spectrum from a {sup 14}C source (E{sub {beta}},{sub max} =156 keV) was chosen for the study. The measured response of a Si(Li) detector to photons (bremsstrahlung) showed fine agreement with the MC calculated photon response, whereas the difference between measured and MC calculated responses to electrons indicates an additional dead layer thickness of about 12 {mu}m in the Si(Li) detector. The depth-dose profiles measured with extrapolation chambers at two laboratories agreed very well, and it was confirmed that the fitting procedure previously reported for {sup 147}Pm depth-dose profiles is also suitable for {beta} radiation from {sup 14}C. An increasing difference between measured and MC calculated dose rates for increasing absorber thickness was found, which is explained by limitations of the EGS4 code for transport of very low-energy electrons (below 10-20 keV). Finally a study of the thermally stimulated exoelectron emission (TSEE) response of BeO thin film dosemeters to {beta} radiation for radiation fields with maximum {beta} energies ranging from 67 keV to 2.27 MeV is reported. For maximum {beta} energies below approximately 500 keV, a decrease in the response amounting to about 20% was observed. It is thus concluded that a {beta} dose higher than about 10 {mu}Gy can be measured with these dosemeters to within 0 to -20% independently of the {beta}energy for E{sub {beta}},{sub max} values down to 67 keV. (au) 12 tabs., 38 ills., 71 refs.

  8. Low energy constraints and scalar leptoquarks⋆

    Directory of Open Access Journals (Sweden)

    Fajfer Svjetlana

    2014-01-01

    Full Text Available The presence of a colored weak doublet scalar state with mass below 1 TeV can provide an explanation of the observed branching ratios in B → D(∗τντ decays. Constraints coming from Z → bb̄, muon g − 2, lepton flavor violating decays are derived. The colored scalar is accommodated within 45 representation of SU(5 group of unification. We show that presence of color scalar can improve mass relations in the up-type quark sector mass. Impact of the colored scalar embedding in 45-dimensional representation of SU(5 on low-energy phenomenology is also presented.

  9. Low Energy Investigations at Kamioka Observatory

    OpenAIRE

    Sekiya, Hiroyuki

    2013-01-01

    At Kamioka Observatory many activities for low energy rare event search are ongoing. Super-Kamiokande(SK), the largest water Cherenkov neutrino detector, currently continues data taking as the fourth phase of the experiment (SK-IV). In SK-IV, we have upgraded the water purification system and tuned water flow in the SK tank. Consequently the background level was lowered significantly. This allowed SK-IV to derive solar neutrino results down to 3.5MeV energy region. With these data, neutrino o...

  10. High Flux Isotope Reactor system RELAP5 input model

    Energy Technology Data Exchange (ETDEWEB)

    Morris, D.G.; Wendel, M.W.

    1993-01-01

    A thermal-hydraulic computational model of the High Flux Isotope Reactor (HFIR) has been developed using the RELAP5 program. The purpose of the model is to provide a state-of-the art thermal-hydraulic simulation tool for analyzing selected hypothetical accident scenarios for a revised HFIR Safety Analysis Report (SAR). The model includes (1) a detailed representation of the reactor core and other vessel components, (2) three heat exchanger/pump cells, (3) pressurizing pumps and letdown valves, and (4) secondary coolant system (with less detail than the primary system). Data from HFIR operation, component tests, tests in facility mockups and the HFIR, HFIR specific experiments, and other pertinent experiments performed independent of HFIR were used to construct the model and validate it to the extent permitted by the data. The detailed version of the model has been used to simulate loss-of-coolant accidents (LOCAs), while the abbreviated version has been developed for the operational transients that allow use of a less detailed nodalization. Analysis of station blackout with core long-term decay heat removal via natural convection has been performed using the core and vessel portions of the detailed model.

  11. Fabrication of control rods for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sease, J.D.

    1998-03-01

    The High Flux Isotope Reactor (HFIR) is a research-type nuclear reactor that was designed and built in the early 1960s and has been in continuous operation since its initial criticality in 1965. Under current plans, the HFIR is expected to continue in operation until 2035. This report updates ORNL/TM-9365, Fabrication Procedure for HFIR Control Plates, which was mainly prepared in the early 1970's but was not issued until 1984, and reflects process changes, lessons learned in the latest control rod fabrication campaign, and suggested process improvements to be considered in future campaigns. Most of the personnel involved with the initial development of the processes and in part campaigns have retired or will retire soon. Because their unlikely availability in future campaigns, emphasis has been placed on providing some explanation of why the processes were selected and some discussions about the importance of controlling critical process parameters. Contained in this report is a description of the function of control rods in the reactor, the brief history of the development of control rod fabrication processes, and a description of procedures used in the fabrication of control rods. A listing of the controlled documents and procedures used in the last fabrication campaigns is referenced in Appendix A.

  12. Ps-atom scattering at low energies

    CERN Document Server

    Fabrikant, I I

    2015-01-01

    A pseudopotential for positronium-atom interaction, based on electron-atom and positron-atom phase shifts, is constructed, and the phase shifts for Ps-Kr and Ps-Ar scattering are calculated. This approach allows us to extend the Ps-atom cross sections, obtained previously in the impulse approximation [Phys. Rev. Lett. 112, 243201 (2014)], to energies below the Ps ionization threshold. Although experimental data are not available in this low-energy region, our results describe well the tendency of the measured cross sections to drop with decreasing velocity at $v<1$ a.u. Our results show that the effect of the Ps-atom van der Waals interaction is weak compared to the polarization interaction in electron-atom and positron-atom scattering. As a result, the Ps scattering length for both Ar and Kr is positive, and the Ramsauer-Townsend minimum is not observed for Ps scattering from these targets. This makes Ps scattering quite different from electron scattering in the low-energy region, in contrast to the inter...

  13. Linac4 Low Energy Beam Measurements with Negative Hydrogen

    CERN Document Server

    Scrivens, R; Crettiez, O; Dimov, V; Gerard, D; Granemann Souza, E; Guida, R; Hansen, J; Lallement, J B; Lettry, J; Lombardi, A; Midttun, O; Pasquino, C; Raich, U; Riffaud, B; Roncarolo, F; Valerio-Lizarraga, C A; Wallner, J; Yarmohammadi Satri, M; Zickler, T

    2014-01-01

    Linac4, a 160 MeV normal-conducting H- linear accelerator, is the first step in the upgrade of the beam intensity available from the LHC proton injectors at CERN. The Linac4 Low Energy Beam Transport (LEBT) line from the pulsed 2 MHz RF driven ion source, to the 352 MHz RFQ has been built and installed at a test stand, and has been used to transport and match to the RFQ a pulsed 14 mA H- beam at 45 keV. A temporary slit-and-grid emittance measurement system has been put in place to characterize the beam delivered to the RFQ. In this paper a description of the LEBT and its beam diagnostics is given, and the results of beam emittance measurements and beam transmission measurements through the RFQ are compared with the expectation from simulations.

  14. The high-flux effect on deuterium retention in TiC and TaC doped tungsten at high temperatures

    NARCIS (Netherlands)

    Zibrov, M.; Bystrov, K.; Mayer, M.; Morgan, T. W.; Kurishita, H.

    2017-01-01

    Samples made of tungsten (W) doped either with titanium carbide (W-1.1TiC) or tantalum carbide (W-3.3TaC) were exposed to a low-energy (40 eV/D), high-flux (1.8–5 × 1023 D/m2s) deuterium (D) plasma at temperatures of about800 K, 1050 K, and 1250 K to a fluence of about1 × 1027 D/m2. The deuterium

  15. High Flux Isotope Reactor cold neutron source reference design concept

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

    1998-05-01

    In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

  16. Level 1 Tornado PRA for the High Flux Beam Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bozoki, G.E.; Conrad, C.S.

    1994-05-01

    This report describes a risk analysis primarily directed at providing an estimate for the frequency of tornado induced damage to the core of the High Flux Beam Reactor (HFBR), and thus it constitutes a Level 1 Probabilistic Risk Assessment (PRA) covering tornado induced accident sequences. The basic methodology of the risk analysis was to develop a ``tornado specific`` plant logic model that integrates the internal random hardware failures with failures caused externally by the tornado strike and includes operator errors worsened by the tornado modified environment. The tornado hazard frequency, as well as earlier prepared structural and equipment fragility data, were used as input data to the model. To keep modeling/calculational complexity as simple as reasonable a ``bounding`` type, slightly conservative, approach was applied. By a thorough screening process a single dominant initiating event was selected as a representative initiator, defined as: ``Tornado Induced Loss of Offsite Power.`` The frequency of this initiator was determined to be 6.37E-5/year. The safety response of the HFBR facility resulted in a total Conditional Core Damage Probability of .621. Thus, the point estimate of the HFBR`s Tornado Induced Core Damage Frequency (CDF) was found to be: (CDF){sub Tornado} = 3.96E-5/year. This value represents only 7.8% of the internal CDF and thus is considered to be a small contribution to the overall facility risk expressed in terms of total Core Damage Frequency. In addition to providing the estimate of (CDF){sub Tornado}, the report documents, the relative importance of various tornado induced system, component, and operator failures that contribute most to (CDF){sub Tornado}.

  17. Dialyzer Reuse and Outcomes of High Flux Dialysis

    Science.gov (United States)

    Argyropoulos, Christos; Roumelioti, Maria-Eleni; Sattar, Abdus; Kellum, John A.; Weissfeld, Lisa; Unruh, Mark L.

    2015-01-01

    Background The bulk of randomized trial evidence for the expanding use of High Flux (HF) hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO) allowed, while the other (Membrane Outcomes Permeability, MPO) excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF) dialyzers. Methods Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M) concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO. Findings In HEMO, minimally reused (reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux reuse and flux of 0.10 and 0.08 respectively). Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51–0.78) for non-reused HF dialyzers compared with non-reused LF membranes. Conclusions This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of HF dialysis and the reuse process on dialyzers may suggest novel biomarkers for uremic toxicity and may accelerate membrane technology innovations that will improve patient outcomes. PMID:26057383

  18. High Flux Metallic Membranes for Hydrogen Recovery and Membrane Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buxbaum, Robert

    2010-06-30

    We made and tested over 250 new alloys for use as lower cost, higher flux hydrogen extraction membrane materials. Most of these were intermetallic, or contained significant intermetallic content, particularly based on B2 alloy compositions with at least one refractory component; B2 intermetallics resemble BCC alloys, in structure, but the atoms have relatively fixed positions, with one atom at the corners of the cube, the other at the centers. The target materals we were looking for would contain little or no expensive elements, no strongly toxic or radioactive elements, would have high flux to hydrogen, while being fabricable, brazable, and relatively immune to hydrogen embrittlement and corrosion in operation. The best combination of properties of the membrane materials we developed was, in my opinion, a Pd-coated membrane consisting of V -9 atomic % Pd. This material was relatively cheap, had 5 times the flux of Pd under the same pressure differential, was reasonably easy to fabricate and braze, and not bad in terms of embrittlement. Based on all these factors we project, about 1/3 the cost of Pd, on an area basis for a membrane designed to last 20 years, or 1/15 the cost on a flux basis. Alternatives to this membrane replaced significant fractions of the Pd with Ni and or Co. The cost for these membranes was lower, but so was the flux. We produced successful brazed products from the membrane materials, and made them into flat sheets. We tested, unsuccessfully, several means of fabricating thematerials into tubes, and eventually built a membrane reactor using a new, flat-plate design: a disc and doughnut arrangement, a design that seems well- suited to clean hydrogen production from coal. The membranes and reactor were tested successfully at Western Research. A larger equipment company (Chart Industries) produced similar results using a different flat-plate reactor design. Cost projections of the membrane are shown to be attractive.

  19. A Petawatt-Laser-Driven, High-Flux Neutron Source for Fusion Micro-Materials Irradiation

    Science.gov (United States)

    Logan, B. G.; Perkins, L. J.; Ditmire, T.; Rosen, M. D.; Perry, M. D.; Key, M. H.; Diaz de La Rubia, T.; Wolfer, W. G.

    1998-11-01

    We are examining the application of petawatt lasers to create beam-target fusion neutrons via ponderomotive-driven, electrostatic coupling. This offers a low cost, high-flux, “micro” 14MeV neutron source for testing tensile strengths of small ( ~100μm) fibers of C, Al_2O_3, SiC, etc., to ~100dpa. Such fibers can form porous fabric tubes for flowing coolant/breeders ( Flibe, LiPb, LiO_2-sand) in a various applications (direct-drive ICF, spheromaks, etc.). Under very short, intense laser heating of a thin tritium-frost layer, ejection of hot (multi-MeV) tail electrons driven by the ponderomotive pressure of the laser field competes with thermal electron heat conduction. Hot ions are ejected from the tritium layer by the resulting potential and move into a deuterium-ice substrate, pre-heated by the hot electrons. Beam-target fusion neutrons are produced at high efficiency (i.e., Q ~0.01-0.1 relative to Q ~0.001 for conventional solid, cold targets), while small target dimensions yield high neutron fluxes. Formal treatment of laser-induced electrostatic potentials is required to accurately model electron/ion transport.

  20. Low Energy Electron Cooler for NICA Booster

    CERN Document Server

    Denisov, A P

    2017-01-01

    BINP has developed an electron cooler to increase the ion accumulation efficiency in the NICA (Nuclotron-based Ion Collider fAcility) heavy ion booster (JINR, Dubna). Adjustment of the cooler magnetic system provides highly homogeneous magnetic field in the cooling section B trans/B long ≤ 4∙10-5 which is vital for efficient electron cooling. First experiments with an electron beam performed at BINP demonstrated the target DC current of 500 mA and electron energy 6 keV.

  1. Low-energy cross section measurements through detection of secondary gamma emission and thick target

    Energy Technology Data Exchange (ETDEWEB)

    Barron P, L.; Chavez L, E.; Huerta H, A.; Ortiz, M.E. [Instituto de Fisica UNAM, A.P. 20-364, 04510 Mexico, D.F. (Mexico); Murillo O, G.; Aguilera, E.F.; Martinez Q, E.; Moreno B, E.; Policroniades R, R.; Varela G, A. [Instituto Nacional de Investigaciones Nucleares, Departamento del Acelerador, A.P. 18-1027, 11801, Mexico, D.F. (Mexico)

    2004-12-01

    In this work, the detection of secondary gamma rays in a tightly shielded Germanium detector, together with a high intensity heavy ion beam on a thick target is used to measure the fusion cross section for the {sup 12} C + {sup 12} C system at very low energies. (Author) 14 refs., 1 tab., 8 figs.

  2. PIP-II Injector Test’s Low Energy Beam Transport: Commissioning and Selected Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Shemyakin, A. [Fermilab; Alvarez, M. [Fermilab; Andrews, R. [Fermilab; Carneiro, J.-P. [Fermilab; Chen, A. [Fermilab; Hanna, B. [Fermilab; Prost, L. [Fermilab; Scarpine, V. [Fermilab; D' Arcy, R. [University Coll. London; Wiesner, C. [Goethe U., Frankfurt (main)

    2016-09-16

    The PIP2IT test accelerator is under construction at Fermilab. Its ion source and Low Energy Beam Transport (LEBT) in its initial (straight) configuration have been commissioned to full specification parameters. This paper introduces the LEBT design and summarizes the outcome of the commissioning activities.

  3. Redesign of a Low Energy Probe Head

    CERN Document Server

    Rao, Yi-Nong; Ries, Thomas

    2005-01-01

    The present situation of the low energy probe LE2 in TRIUMF cyclotron is that the thickness of the finger 5 is uniform over a radial length of 3.25 inch and its weight which amounts to ~447 g is affecting its re-circulating ball mechanism and causing it to fall below the median plane over its range of movement. We therefore re-design it in order to reduce its weight. First, we made simulations and determined the optimum thickness of the probe head vs its radial length. These simulation results are found to be in good agreement with experimental measurements made. Finally, we calculated the temperature rise caused by the beam power dumped on the probe, and figured out the maximum current of beam that can be dumped on the finger.

  4. Low-energy neutrino factory design

    Directory of Open Access Journals (Sweden)

    C. Ankenbrandt

    2009-07-01

    Full Text Available The design of a low-energy (4 GeV neutrino factory (NF is described, along with its expected performance. The neutrino factory uses a high-energy proton beam to produce charged pions. The π^{±} decay to produce muons (μ^{±}, which are collected, accelerated, and stored in a ring with long straight sections. Muons decaying in the straight sections produce neutrino beams. The scheme is based on previous designs for higher energy neutrino factories, but has an improved bunching and phase rotation system, and new acceleration, storage ring, and detector schemes tailored to the needs of the lower energy facility. Our simulations suggest that the NF scheme we describe can produce neutrino beams generated by ∼1.4×10^{21} μ^{+} per year decaying in a long straight section of the storage ring, and a similar number of μ^{-} decays.

  5. Wire scanners in low energy accelerators

    CERN Document Server

    Elmfors, P; Huhtinen, M; Lindroos, M; Olsfors, J; Raich, U

    1997-01-01

    Fast wire scanners are today considered as part of standard instrumentation in high energy synchrotrons. The extension of their use to synchrotrons working at lower energies, where Coulomb scattering can be important and the transverse beam size is large, introduces new complications considering beam heating of the wire, composition of the secondary particle shower and geometrical consideration in the detection set-up. A major problem in treating these effects is that the creation of secondaries in a thin carbon wire by a energetic primary beam is difficult to describe in an analytical way. We are here presenting new results from a full Monte Carlo simulation of this process yielding information on heat deposited in the wire, particle type and energy spectrum of secondaries and angular dependence as a function of primary beam energy. The results are used to derive limits for the use of wire scanners in low energy accelerators.

  6. Low-energy dynamics of gravitation

    Science.gov (United States)

    Torma, Tibor

    The present status of theories of quantum gravity are reviewed from the low energy point of view. String theory relates classical black-hole type solutions of Einstein- like equations (e.g. axidilaton gravity) to the string vacuum. Several such solutions are proposed and their properties are investigated, including their behavior under supersymmetry transformations. A general feature of all possible quantum theories of gravitation is that they lead to a field theory description at low (as compared to the Planck mass) energies. The theoretical consistency, uniqueness and consequences of such an effective theory are investigated. I show that a power counting theorem allows for the momentum expansion that defines the effective theory even in the presence of large masses. I also show that graviton-graviton scattering is free of potential infrared and collinear divergencies that plague perturbative discussions of Yang-Mills theories.

  7. Low-energy neutrino factory design

    Energy Technology Data Exchange (ETDEWEB)

    Ankenbrandt, C.; /Fermilab /MUONS Inc., Batavia; Bogacz, S.A.; /Jefferson Lab; Bross, A.; Geer, S.; Johnstone, C.; Neuffer, D.; Popovic, M.; /Fermilab

    2009-07-01

    The design of a low-energy (4 GeV) neutrino factory (NF) is described, along with its expected performance. The neutrino factory uses a high-energy proton beam to produce charged pions. The {pi}{sup {+-}} decay to produce muons ({mu}{sup {+-}}), which are collected, accelerated, and stored in a ring with long straight sections. Muons decaying in the straight sections produce neutrino beams. The scheme is based on previous designs for higher energy neutrino factories, but has an improved bunching and phase rotation system, and new acceleration, storage ring, and detector schemes tailored to the needs of the lower energy facility. Our simulations suggest that the NF scheme we describe can produce neutrino beams generated by {approx} 1.4 x 10{sup 21} {mu}{sup +} per year decaying in a long straight section of the storage ring, and a similar number of {mu}{sup -} decays.

  8. LEAR (Low Energy Antiproton Ring), general view.

    CERN Document Server

    1990-01-01

    When the Antiproton Project was launched in the late 1970s, it was recognized that in addition to the primary purpose of high-energy proton-antiproton collisions in the SPS, there was interesting physics to be done with low-energy antiprotons. In 1982, LEAR was ready to receive antiprotons from the Antiproton Accumulator (AA), via the PS. A year later, delivery of antiprotons to the experiments began, at momenta as low as 100 MeV/c (kinetic energy 5.3 MeV), in an "Ultra-Slow Extraction" mode, dispensing some E9 antiprotons over times counted in hours. For such an achievement, stochastic and electron cooling had to be brought to high levels of perfection.

  9. Bluetooth Low Energy Mesh Networks: A Survey.

    Science.gov (United States)

    Darroudi, Seyed Mahdi; Gomez, Carles

    2017-06-22

    Bluetooth Low Energy (BLE) has gained significant momentum. However, the original design of BLE focused on star topology networking, which limits network coverage range and precludes end-to-end path diversity. In contrast, other competing technologies overcome such constraints by supporting the mesh network topology. For these reasons, academia, industry, and standards development organizations have been designing solutions to enable BLE mesh networks. Nevertheless, the literature lacks a consolidated view on this emerging area. This paper comprehensively surveys state of the art BLE mesh networking. We first provide a taxonomy of BLE mesh network solutions. We then review the solutions, describing the variety of approaches that leverage existing BLE functionality to enable BLE mesh networks. We identify crucial aspects of BLE mesh network solutions and discuss their advantages and drawbacks. Finally, we highlight currently open issues.

  10. Windows in Low Energy Houses. Size Matters

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Mari-Louise

    2004-06-01

    A generally accepted way of building passive houses has been to have small windows facing north and a large glass facade to the south. This is to minimize losses on the north side while gaining as much solar heat as possible on the south. In spring 2001, twenty terraced houses were built outside Goeteborg partly in this way. The indoor temperature is kept at a comfortable level by passive methods, using solar gains and internal gains from household appliances and occupants. Heat losses are very low, since the building envelope is well insulated and since modern coated triple-glazed windows have been installed. The purpose of this work is to investigate how decreasing the window size facing south and increasing the window size facing north in low energy houses will influence the energy consumption and maximum power needed to keep the indoor temperature between 23 and 26 deg C. Different climates and orientations have been investigated and so have the influence of occupancy and window type. A dynamic building simulation tool, DEROB, has been used and the simulations indicate an extremely low energy demand for the houses. The results show that the size of the energy efficient windows does not have a major influence on the heating demand in winter, but is of relevant signification looking at the cooling need in summer. This indicates that instead of the traditional technique of building passive houses it is possible to enlarge the window area facing north and get better lighting conditions. To decrease the energy need for cooling, there is an optimal window size facing south that is smaller than the original size of the investigated buildings.

  11. Low energy AMS of americium and curium

    Energy Technology Data Exchange (ETDEWEB)

    Christl, Marcus, E-mail: mchristl@ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Dai, Xiongxin [AECL Chalk River Laboratories, Chalk River, Ontario K0J 1J0 (Canada); Lachner, Johannes [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Kramer-Tremblay, Sheila [AECL Chalk River Laboratories, Chalk River, Ontario K0J 1J0 (Canada); Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland)

    2014-07-15

    Accelerator mass spectrometry (AMS) has evolved over the past years as one of the most sensitive, selective, and robust techniques for actinide analyses. While analyses of U and Pu isotopes have already become routine at the ETH Zurich 0.5 MV AMS system “Tandy”, there is an increasing demand for highly sensitive analyses of the higher actinides such as Am and Cm for bioassay applications and beyond. In order to extend the actinide capabilities of the compact ETH Zurich AMS system and to develop new, more sensitive bioassay routines, a pilot study was carried out. The aim was to investigate and document the performance and the potential background of Am and Cm analyses with low energy AMS. Our results show that {sup 241}Am and Cm isotopes can be determined relative to a {sup 243}Am tracer if samples and AMS standards are prepared identically with regard to the matrix elements, in which the sample is dispersed. In this first test, detection limits for Cm and Am isotopes are all in the sub-femtogram range and even below 100 ag for Cm isotopes. In a systematic background study in the mass range of the Cm isotopes, two formerly unknown metastable triply charged Th molecules were found on amu(244) and amu(248). The presence of such a background is not a principal problem for AMS if the stripper pressure is increased accordingly. Based on our first results, we conclude that ultra-trace analyses of Am and Cm isotopes for bioassay are very well possible with low energy AMS.

  12. Reprint of Low-energy electron potentiometry.

    Science.gov (United States)

    Jobst, Johannes; Kautz, Jaap; Mytiliniou, Maria; Tromp, Rudolf M; van der Molen, Sense Jan

    2017-12-01

    In a lot of systems, charge transport is governed by local features rather than being a global property as suggested by extracting a single resistance value. Consequently, techniques that resolve local structure in the electronic potential are crucial for a detailed understanding of electronic transport in realistic devices. Recently, we have introduced a new potentiometry method based on low-energy electron microscopy (LEEM) that utilizes characteristic features in the reflectivity spectra of layered materials [1]. Performing potentiometry experiments in LEEM has the advantage of being fast, offering a large field of view and the option to zoom in and out easily, and of being non-invasive compared to scanning-probe methods. However, not all materials show clear features in their reflectivity spectra. Here we, therefore, focus on a different version of low-energy electron potentiometry (LEEP) that uses the mirror mode transition, i.e. the drop in electron reflectivity around zero electron landing energy when they start to interact with the sample rather than being reflected in front of it. This transition is universal and sensitive to the local electrostatic surface potential (either workfunction or applied potential). It can consequently be used to perform LEEP experiments on a broader range of material compared to the method described in Ref[1]. We provide a detailed description of the experimental setup and demonstrate LEEP on workfunction-related intrinsic potential variations on the Si(111) surface and for a metal-semiconductor-metal junction with external bias applied. In the latter, we visualize the Schottky effect at the metal-semiconductor interface. Finally, we compare how robust the two LEEP techniques discussed above are against image distortions due to sample inhomogeneities or contamination. Copyright © 2017. Published by Elsevier B.V.

  13. Low energy AMS of americium and curium

    Science.gov (United States)

    Christl, Marcus; Dai, Xiongxin; Lachner, Johannes; Kramer-Tremblay, Sheila; Synal, Hans-Arno

    2014-07-01

    Accelerator mass spectrometry (AMS) has evolved over the past years as one of the most sensitive, selective, and robust techniques for actinide analyses. While analyses of U and Pu isotopes have already become routine at the ETH Zurich 0.5 MV AMS system "Tandy", there is an increasing demand for highly sensitive analyses of the higher actinides such as Am and Cm for bioassay applications and beyond. In order to extend the actinide capabilities of the compact ETH Zurich AMS system and to develop new, more sensitive bioassay routines, a pilot study was carried out. The aim was to investigate and document the performance and the potential background of Am and Cm analyses with low energy AMS. Our results show that 241Am and Cm isotopes can be determined relative to a 243Am tracer if samples and AMS standards are prepared identically with regard to the matrix elements, in which the sample is dispersed. In this first test, detection limits for Cm and Am isotopes are all in the sub-femtogram range and even below 100 ag for Cm isotopes. In a systematic background study in the mass range of the Cm isotopes, two formerly unknown metastable triply charged Th molecules were found on amu(244) and amu(248). The presence of such a background is not a principal problem for AMS if the stripper pressure is increased accordingly. Based on our first results, we conclude that ultra-trace analyses of Am and Cm isotopes for bioassay are very well possible with low energy AMS.

  14. Microdosimetry of low-energy electrons.

    Science.gov (United States)

    Liamsuwan, Thiansin; Emfietzoglou, Dimitris; Uehara, Shuzo; Nikjoo, Hooshang

    2012-12-01

    To investigate differences in energy depositions and microdosimetric parameters of low-energy electrons in liquid and gaseous water using Monte Carlo track structure simulations. KURBUC-liq (Kyushu University and Radiobiology Unit Code for liquid water) was used for simulating electron tracks in liquid water. The inelastic scattering cross sections of liquid water were obtained from the dielectric response model of Emfietzoglou et al. (Radiation Research 2005;164:202-211). Frequencies of energy deposited in nanometre-size cylindrical targets per unit absorbed dose and associated lineal energies were calculated for 100-5000 eV monoenergetic electrons and the electron spectrum of carbon K edge X-rays. The results for liquid water were compared with those for water vapour. Regardless of electron energy, there is a limit how much energy electron tracks can deposit in a target. Phase effects on the frequencies of energy depositions are largely visible for the targets with diameters and heights smaller than 30 nm. For the target of 2.3 nm by 2.3 nm (similar to dimension of DNA segments), the calculated frequency- and dose-mean lineal energies for liquid water are up to 40% smaller than those for water vapour. The corresponding difference is less than 12% for the targets with diameters ≥ 30 nm. Condensed-phase effects are non-negligible for microdosimetry of low-energy electrons for targets with sizes smaller than a few tens of nanometres, similar to dimensions of DNA molecular structures and nucleosomes.

  15. Low-energy charged particles in Saturn's magnetosphere - Results from Voyager 1

    Science.gov (United States)

    Krimigis, S. M.; Bostrom, C. O.; Keath, E. P.; Carbary, J. F.; Roelof, E. C.; Armstrong, T. P.; Axford, W. I.; Gloeckler, G.; Hamilton, D. C.; Lanzerotti, L. J.

    1981-01-01

    The Voyager 1 low-energy charged particle instrument measured electrons and ions with energies below 26 and 40 kiloelectron volts, respectively, in the Saturn magnetosphere. Spectra of all ion species were found to have an energy cutoff at levels greater than 2 million electron volts. In contrast to the magnetospheres of Jupiter and earth, there are no lobe regions essentially devoid of particles in Saturn's nighttime magnetosphere. One novel feature of the Saturn magnetosphere is a pervasive population of energetic molecular hydrogen.

  16. Dissolution flowsheet for high flux isotope reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Foster, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-27

    As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U3O8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H2. The HFIR fuel cores will be dissolved and the recovered U will be down-blended into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H2 and other permanent gases in the dissolution offgas allowing the development of H2 generation rate profiles. The H2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the

  17. Dialyzer Reuse and Outcomes of High Flux Dialysis.

    Directory of Open Access Journals (Sweden)

    Christos Argyropoulos

    Full Text Available The bulk of randomized trial evidence for the expanding use of High Flux (HF hemodialysis worldwide comes from two randomized controlled trials, one of which (HEMODIALYSIS, HEMO allowed, while the other (Membrane Outcomes Permeability, MPO excluded, the reuse of membranes. It is not known whether dialyzer reuse has a differential impact on outcomes with HF vs low flyx (LF dialyzers.Proportional Hazards Models and Joint Models for longitudinal measures and survival outcomes were used in HEMO to analyze the relationship between β2-microglobulin (β2M concentration, flux, and reuse. Meta-analysis and regression techniques were used to synthesize the evidence for HF dialysis from HEMO and MPO.In HEMO, minimally reused (< 6 times HF dialyzers were associated with a hazard ratio (HR of 0.67 (95% confidence interval, 95%CI: 0.48-0.92, p = 0.015, 0.64 (95%CI: 0.44 - 0.95, p = 0.03, 0.61 (95%CI: 0.41 - 0.90, p = 0.012, 0.53 (95%CI: 0.28 - 1.02, p = 0.057 relative to minimally reused LF ones for all cause, cardiovascular, cardiac and infectious mortality respectively. These relationships reversed for extensively reused membranes (p for interaction between reuse and flux < 0.001, p = 0.005 for death from all cause and cardiovascular causes, while similar trends were noted for cardiac and infectious mortality (p of interaction between reuse and flux of 0.10 and 0.08 respectively. Reduction of β2M explained only 1/3 of the effect of minimally reused HF dialyzers on all cause mortality, while non-β2M related factors explained the apparent attenuation of the benefit with more extensively reused dialyzers. Meta-regression of HEMO and MPO estimated an adjusted HR of 0.63 (95% CI: 0.51-0.78 for non-reused HF dialyzers compared with non-reused LF membranes.This secondary analysis and synthesis of two large hemodialysis trials supports the widespread use of HF dialyzers in clinical hemodialysis over the last decade. A mechanistic understanding of the effects of

  18. Low energy electron scattering from fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, M. Cristina A.; Silva, Daniel G.M.; Coelho, Rafael F.; Duque, Humberto V.; Santos, Rodrigo R. dos; Ribeiro, Thiago M. [Universidade Federal de Juiz de Fora (UFJF), MG (Brazil). Dept. de Fisica; Yates, Brent; Hong, Ling; Khakoo, Murtadha A. [California State University at Fullerton, CA (US). Physics Department; Bettega, Marcio H.F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Fisica; Costa, Romarly F. da [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas; Lima, Marco A.P. [Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE/CNPEM), Campinas, SP (Brazil)

    2011-07-01

    Full text. Accurate and precise values of absolute total cross section (TCS) represent important information in many scientific and technological applications. In our case, for example, we are motivated to provide such information for electron-fuel collision processes which are specifically relevant to modeling spark ignition in alcohol-fuelled internal combustion engines. Many electron scattering TCS measurements are presently available for a diverse range of atomic and molecular targets. However, lack of data for important bio-molecular targets still remains. Disagreements between the available TCS data for the alcohols have prompted several studies of electron scattering collision of slow electrons with these molecules which are currently important in applications as bio- fuels. This relevance, which has attracted much attention, has been one of the subjects of a recent collaboration between experimental and theoretical groups in the USA and Brazil. Recently this collaboration reported first measurements and calculations of differential cross sections for elastic low-energy (rotationally unresolved) electron scattering by several primary alcohols. In this work we address methanol and ethanol TCSs at low energy range and report additional studies of resonant structure in ethanol using the detection of metastable states produced by electron impact excitation with high energy resolution. We have recently constructed a TCS apparatus in our laboratory at Universidade Federal de Juiz de Fora, Brazil, based on the well-known linear transmission technique. The experimental setup is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the atoms or molecules to be studied at a given pressure. It consists essentially of an electron gun, a gas cell and an electron energy analyzer composed of an array of decelerating electrostatic lenses, a cylindrical dispersive 127o analyzer and a Faraday cup. To our knowledge, there exist

  19. Low-Energy Plasma Focus Device as an Electron Beam Source

    Directory of Open Access Journals (Sweden)

    Muhammad Zubair Khan

    2014-01-01

    Full Text Available A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5×1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences.

  20. Low-Energy Plasma Focus Device as an Electron Beam Source

    Science.gov (United States)

    Seong Ling, Yap; Naresh Kumar, Nitturi; Lian Kuang, Lim; Chiow San, Wong

    2014-01-01

    A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 1016/m3, respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences. PMID:25544952

  1. Effects of low-energy N(+)-beam implantation on root growth in Arabidopsis seedlings.

    Science.gov (United States)

    Zhang, Liang; Qi, Wencai; Xu, Hangbo; Wang, Lin; Jiao, Zhen

    2016-02-01

    The effects of ion implantation on the morphology changes and biological responses of plants are dependent on implantation doses. Previous studies mainly focus on the application of ion-beam technology in genetic mutation. Our knowledge regarding the mechanism underlying the plant growth inhibition induced by ion implantation remains limited. In this study, we explore the responses of root growth to low-energy N(+)-beam implantation using implanted Arabidopsis seeds. Our results showed that the root and root tip length were obviously reduced by implantation with large doses of low-energy N(+) beam. The analysis of confocal images showed that ion implantation reduced the cell viability and cell division activity in root meristem. The production rate of superoxide radical (O2(•-)) and contents of hydrogen peroxide (H2O2) in roots under ion implantation were markedly higher than those of controls. Transcriptional expression analysis of selected genes revealed that Arabidopsis RBOH genes associated with reactive oxygen species (ROS) production were significantly up-regulated in roots in response to ion implantation. The activities of antioxidant enzymes were also induced by ion implantation. Moreover, ROS scavenging obviously enhanced cell viability and cell division in response to ion implantation and alleviated the root growth inhibition of the implanted seedlings. Our results suggest that the overproduction of ROS induced by ion implantation is involved in the inhibitory effect of low-energy ion beam on root growth by affecting the cell viability and cell division of root meristem in Arabidopsis seedlings. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Low Energy Electron Scattering from Fuels

    Science.gov (United States)

    Lopes, M. Cristina A.

    2012-06-01

    We report an investigation of processes that occur during the ignition of the plasma and its consequences in post-discharge time for an internal combustion engine, in order to find the appropriate parameters to be used in cars that operate with lean mixtures air-fuel. The relevance of this theme has attracted much attention, and has been one of the subjects of collaboration between experimental and theoretical groups in the USA and Brazil. We have produced some basic information necessary to modeling spark ignition in alcohol- fuelled engines. Total cross sections of electron scattering by methanol and ethanol molecules were obtained, using the linear transmission method based on the Beer-Lambert law to first approximation. Measurements and calculations of differential cross sections for low-energy (rotationally unresolved) electron scattering were also obtained, for scattering angles of 5 --130 . The measurements were taken using the relative flow method with an aperture source, and calculations using two different implementations of the Schwinger multichannel method, one that takes all electrons into account and is adapted for parallel computers, and another that uses pseudopotentials and considers only the valence electrons. Additionally to these, computer simulation studies of electronic discharge in mixtures of ethanol were performed, using a Zero-Dimensional Plasma Kinetic solver. Previous reported models for combustion of ethanol and cross sections data for momentum transfer of electron collisions with ethanol were used. The time evolutions of the main species densities are reported and the ignition time delay discussed.

  3. Universality of low-energy Rashba scattering

    Science.gov (United States)

    Hutchinson, Joel; Maciejko, Joseph

    2017-09-01

    We investigate the scattering of a quantum particle with a two-dimensional (2D) Rashba spin-orbit coupled dispersion off of circularly symmetric potentials. As the energy of the particle approaches the bottom of the lowest spin-split band, i.e., the van Hove singularity, earlier work has shown that scattering off of an infinite circular barrier exhibits a number of features unusual from the point of view of conventional 2D scattering theory: the low-energy S matrix is independent of the range of the potential, all partial waves contribute equally, the differential cross section becomes increasingly anisotropic and 1D-like, and the total cross section exhibits quantized plateaus. Via a nonperturbative determination of the T matrix and an optical theorem which we prove here, we show that this behavior is universal for Rashba scattering off of any circularly symmetric, spin independent, finite-range potential. This is relevant both for impurity scattering in the noninteracting limit as well as for short-range two-particle scattering in the interacting problem.

  4. Exploring neutrino mixing with low energy superbeams

    Science.gov (United States)

    Minakata, Hisakazu; Nunokawa, Hiroshi

    2001-10-01

    We explore the features of neutrino oscillation which are relevant for measurements of the leptonic CP violating phase δ and the sign of Δm213 in experiments with low-energy conventional superbeams. Toward the goal, we introduce a new powerful tool called the ``CP trajectory diagram in bi-probability space'' which allows us to represent pictorially the three effects, the effects of (a) genuine CP violation due to the sin δ term, (b) CP conserving cos δ term, and (c) fake CP violation due to earth matter, separately in a single diagram. By using the diagram, we observe that there is a two-fold ambiguity in the determination of δ which is related with the sign of Δm213. Possible ways of resolving the ambiguity are discussed. In particular, we point out that an in situ simultaneous measurement of δ and the sign of Δm213 can be carried out at distances of about 700 km, or at the Phase II of the JHF experiment provided that sin δ · Δm213 < 0, both with a megaton class water Cherenkov detector.

  5. Low Energy Desalination Using Battery Electrode Deionization

    KAUST Repository

    Kim, Taeyoung

    2017-09-21

    New electrochemical technologies that use capacitive or battery electrodes are being developed to minimize energy requirements for desalinating brackish waters. When a pair of electrodes is charged in capacitive deionization (CDI) systems, cations bind to the cathode and anions bind to the anode, but high applied voltages (>1.2 V) result in parasitic reactions and irreversible electrode oxidation. In the battery electrode deionization (BDI) system developed here, two identical copper hexacyanoferrate (CuHCF) battery electrodes were used that release and bind cations, with anion separation occurring via an anion exchange membrane. The system used an applied voltage of 0.6 V, which avoided parasitic reactions, achieved high electrode desalination capacities (up to 100 mg-NaCl/g-electrode, 50 mM NaCl influent), and consumed less energy than CDI. Simultaneous production of desalinated and concentrated solutions in two channels avoided a two-cycle approach needed for CDI. Stacking additional membranes between CuHCF electrodes (up to three anion and two cation exchange membranes) reduced energy consumption to only 0.02 kWh/m3 (approximately an order of magnitude lower than values reported for CDI), for an influent desalination similar to CDI (25 mM decreased to 17 mM). These results show that BDI could be effective as a very low energy method for brackish water desalination.

  6. Low Energy Investigations at Kamioka Observatory

    Science.gov (United States)

    Sekiya, Hiroyuki

    2013-10-01

    At Kamioka Observatory many activities for low energy rare event search are ongoing. Super-Kamiokande(SK), the largest water Cherenkov neutrino detector, currently continues data taking as the fourth phase of the experiment (SK-IV). In SK-IV, we have upgraded the water purification system and tuned water flow in the SK tank. Consequently the background level was lowered significantly. This allowed SK-IV to derive solar neutrino results down to 3.5 MeV energy region. With these data, neutrino oscillation parameters are updated from global fit; Δm212 = 7.44+0.2-0.19 × 10-5eV2, sin2 θ12 = 0.304 ± 0.013, sin2 θ13 = 0.0301+0.017-0.015. NEWAGE, the directional sensitive dark matter search experiment, is currently operated as "NEWAGE-0.3a" which is a 0.20 × 0.25 × 0.31 m3 micro-TPC filled with CF4 gas at 152 Torr. Recently we have developed "NEWAGE-0.3b". It was succeeded to lower the operation pressure down to 76 Torr and the threshold down to 50 keV (F recoils). XMASS experiment is looking for scintillation signals from dark matter interaction in 1 ton of liquid xenon. It was designed utilizing its self-shielding capability with fiducial volume confinement. However, we could lower the analysis threshold down to 0.3 keVee using whole volume of the detector. In February 2012, low threshold and very large exposure data (5591 kg·days) were collected. With these data, we have excluded some part of the parameter spaces claimed by DAMA/LIBRA and CoGeNT experiments.

  7. Status of the low-energy super-heavy element facility at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Schury, P., E-mail: schury@riken.jp [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wada, M.; Ito, Y. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Arai, F. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Kaji, D. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Kimura, S. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Morimoto, K.; Haba, H. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Jeong, S. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Koura, H. [Advanced Science Research Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Miyatake, H. [Institute of Particle and Nuclear Studies (IPNS), High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801 (Japan); Morita, K.; Reponen, M. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Ozawa, A. [Institute of Physics, University of Tsukuba, Tsukuba City, Ibaraki (Japan); Sonoda, T.; Takamine, A. [RIKEN, Nishina Center for Accelerator Based Science, Wako City, Saitama (Japan); Wollnik, H. [Dept. Chemistry and BioChemistry, New Mexico State University, Las Cruces, NM (United States)

    2016-06-01

    In order to investigate nuclei produced via fusion–evaporation reactions, especially super-heavy elements (SHE), we have begun construction of a facility for conversion of fusion–evaporation residues (EVR) to low-energy beams. At the base of this facility is a small cryogenic gas cell utilizing a traveling wave RF-carpet, located directly following the gas-filled recoil ion separator GARIS-II, which will thermalize EVRs to convert them into ion beams amenable to ion trapping. We present here the results of initial studies of this small gas cell.

  8. Dissolution Flowsheet for High Flux Isotope Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Daniel, W. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Rudisill, T. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); O' Rourke, P. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Karay, N. S [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-27

    As part of the Spent Nuclear Fuel (SNF) processing campaign, H-Canyon is planning to begin dissolving High Flux Isotope Reactor (HFIR) fuel in late FY17 or early FY18. Each HFIR fuel core contains inner and outer fuel elements which were fabricated from uranium oxide (U3O8) dispersed in a continuous Al phase using traditional powder metallurgy techniques. Fuels fabricated in this manner, like other SNF’s processed in H-Canyon, dissolve by the same general mechanisms with similar gas generation rates and the production of H2. The HFIR fuel cores will be dissolved and the recovered U will be down-blended into low-enriched U. HFIR fuel was previously processed in H-Canyon using a unique insert in both the 6.1D and 6.4D dissolvers. Multiple cores will be charged to the same dissolver solution maximizing the concentration of dissolved Al. The objective of this study was to identify flowsheet conditions through literature review and laboratory experimentation to safely and efficiently dissolve the HFIR fuel in H-Canyon. Laboratory-scale experiments were performed to evaluate the dissolution of HFIR fuel using both Al 1100 and Al 6061 T6 alloy coupons. The Al 1100 alloy was considered a representative surrogate which provided an upper bound on the generation of flammable (i.e., H2) gas during the dissolution process. The dissolution of the Al 6061 T6 alloy proceeded at a slower rate than the Al 1100 alloy, and was used to verify that the target Al concentration in solution could be achieved for the selected Hg concentration. Mass spectrometry and Raman spectroscopy were used to provide continuous monitoring of the concentration of H2 and other permanent gases in the dissolution offgas, allowing the development of H2 generation rate profiles. The H2 generation rates were subsequently used to evaluate if a full HFIR core could be dissolved in an H-Canyon dissolver without exceeding 60% of the

  9. Design of Low-Energy District Heating System for a Settlement with Low-Energy Buildings

    DEFF Research Database (Denmark)

    Tol, Hakan; Svendsen, Svend

    2011-01-01

    With the integration of new low-energy buildings the traditional district heating (DH) systems with high operating temperatures will have significantly higher heat loss according to the heat supplied to the district. The relatively higher heat loss could be reduced with low operating temperatures...... of 55 °C and 25 °C in supply and return line of DH network, respectively with a convenient control of in-house installations (substations). Traditional DH pipe dimensioning methods were based on size searching algorithm in which lowest possible pipe diameter was defined according to the limit of max...

  10. Low-energy charged particle environment at Jupiter - A first look

    Science.gov (United States)

    Krimigis, S. M.; Bostrom, C. O.; Keath, E. P.; Zwickl, R. D.; Carbary, J. F.; Armstrong, T. P.; Axford, W. I.; Fan, C. Y.; Gloeckler, G.; Lanzerotti, L. J.

    1979-01-01

    Preliminary results of measurements obtained by the low energy charged particle instrument on board the Voyager 1 spacecraft during its traversal of the Jovian magnetosphere are reported. The instrument consists of the low energy particle telescope and the low energy magnetospheric particle analyzer, designed to perform measurements in the inner and outer magnetosphere respectively. Ions and electrons comprising the Jovian magnetosphere were first detected at a distance of about 600 Jupiter radii from the planet, with the first bow shock crossing at 85.6 Jupiter radii. Upon crossing the magnetopause at about 67 Jupiter radii, the flows of electrons and ions were observed to change direction from away from the planet to the corotational direction. The hot plasma near the magnetosphere boundary is comprised predominantly of protons, sulfur and oxygen. Selective particle absorption near the Io flux tube indicates some form of particle deflection by Io. Fluxes in the outbound region were found to be enhanced from 90 to 160 deg longitude, and 5- and 10-hour low energy particle flux periodicities were observed.

  11. Low-Energy Ballistic Transfers to Lunar Halo Orbits

    Science.gov (United States)

    Parker, Jeffrey S.

    2009-01-01

    Recent lunar missions have begun to take advantage of the benefits of low-energy ballistic transfers between the Earth and the Moon rather than implementing conventional Hohmann-like lunar transfers. Both Artemis and GRAIL plan to implement low-energy lunar transfers in the next few years. This paper explores the characteristics and potential applications of many different families of low-energy ballistic lunar transfers. The transfers presented here begin from a wide variety of different orbits at the Earth and follow several different distinct pathways to the Moon. This paper characterizes these pathways to identify desirable low-energy lunar transfers for future lunar missions.

  12. Reconfigurable Low Energy Multiplier for Multimedia System Design

    National Research Council Canada - National Science Library

    Kim, Suhwan

    2000-01-01

    This paper proposes a reconfigurable pipelined multiplier architecture that achieves high performance and very low energy dissipation by adapting its structure to computational requirements over time...

  13. The Exploitation of Low-Energy Electrons in Cancer Treatment.

    Science.gov (United States)

    Rezaee, Mohammad; Hill, Richard P; Jaffray, David A

    2017-08-01

    Given the distinct characteristics of low-energy electrons (LEEs), particularly at energies less than 30 eV, they can be applied to a wide range of therapeutic modalities to improve cancer treatment. LEEs have been shown to efficiently produce complex molecular damage resulting in substantial cellular toxicities. Since LEEs are produced in copious amounts from high-energy radiation beam, including photons, protons and ions; the control of LEE distribution can potentially enhance the therapeutic radio of such beams. LEEs can play a substantial role in the synergistic effect between radiation and chemotherapy, particularly halogenated and platinum-based anticancer drugs. Radiosensitizing entities containing atoms of high atomic number such as gold nanoparticles can be a source of LEE production if high-energy radiation interacts with them. This can provide a high local density of LEEs in a cell and produce cellular toxicity. Auger-electron-emitting radionuclides also create a high number of LEEs in each decay, which can induce lethal damage in a cell. Exploitation of LEEs in cancer treatment, however, faces a few challenges, such as dosimetry of LEEs and selective delivery of radiosensitizing and chemotherapeutic molecules close to cellular targets. This review first discusses the rationale for utilizing LEEs in cancer treatment by explaining their mechanism of action, describes theoretical and experimental studies at the molecular and cellular levels, then discusses strategies for achieving modification of the distribution and effectiveness of LEEs in cancerous tissue and their associated clinical benefit.

  14. Apparatus for high flux photocatalytic pollution control using a rotating fluidized bed reactor

    Science.gov (United States)

    Tabatabaie-Raissi, Ali; Muradov, Nazim Z.; Martin, Eric

    2003-06-24

    An apparatus based on optimizing photoprocess energetics by decoupling of the process energy efficiency from the DRE for target contaminants. The technique is applicable to both low- and high-flux photoreactor design and scale-up. An apparatus for high-flux photocatalytic pollution control is based on the implementation of multifunctional metal oxide aerogels and other media in conjunction with a novel rotating fluidized particle bed reactor.

  15. {sup 12}C+{sup 12}C cross-section measurements at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Barron-Palos, L.; Chavez L., E.; Huerta H., A.; Ortiz, M.E. [Ciudad Universitaria, Instituto de Fisica UNAM, Mexico (Mexico); Murillo O., G.; Aguilera R., E.; Martinez Q., E.; Moreno, E.; Policroniades R., R.; Varela G., A. [Instituto Nacional de Investigaciones Nucleares, Departamento del Acelerador, Salazar (Mexico)

    2005-09-01

    In order to study the {sup 12}C+{sup 12}C reaction at low energies, a combination of an intense heavy ion beam on a thick target and the detection of secondary gamma rays on a well-shielded germanium detector has been used. Preliminary cross-section results are reported for E{sub c.m.}=2.63-3.45 MeV. (orig.)

  16. Low-energy-consumption hybrid lasers for silicon photonics

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Ran, Qijiang; Mørk, Jesper

    2012-01-01

    Physics and characteristics of a hybrid vertical-cavity laser that can be an on-chip Si light source with high speed and low energy consumption are discussed.......Physics and characteristics of a hybrid vertical-cavity laser that can be an on-chip Si light source with high speed and low energy consumption are discussed....

  17. Occupant Experiences and Satisfaction with New Low-Energy Houses

    DEFF Research Database (Denmark)

    Knudsen, Henrik Nellemose; Thomsen, Kirsten Engelund; Mørck, Ove

    2013-01-01

    The development and the erection of low-energy buildings have been intensified in recent years. Still, there are only few studies on occupant experiences and satisfaction of living in low-energy houses. A questionnaire survey was therefore carried out in the autumn 2011 among occupants of low-ene...

  18. What is a low-energy house and who cares?

    Energy Technology Data Exchange (ETDEWEB)

    Litt, B.R.

    1994-12-01

    Most energy analysts view low-energy houses as good things, yet differ in their expectations of what exactly a low energy house is. There are two intertwining threads to this report. The first is an evaluation of 50 buildings that have been claimed to be low-energy residences, for which monitored energy performance data have been collected. These data represent the preliminary effort in the ongoing update of the Buildings Energy-Use Compilation and Analysis (BECA) data base for new residences. The second thread concerns the definition of a low-energy house. After the elements of a definition are presented, their implications for actors involved in providing housing are identified. Several more tractable definitions are applied to the houses in this compilation. The outcomes illustrate ways in which different interests are served by various definitions. Different definitions can yield very different energy rankings. No single definition of a low-energy house is universally applicable.

  19. The production of low-energy neutral oxygen beams by grazing-incidence neutralization

    Science.gov (United States)

    Albridge, R. G.; Haglund, R. F.; Tolk, N. H.; Daech, A. F.

    1987-01-01

    The Vanderbilt University neutral oxygen facility produces beams of low-energy neutral oxygen atoms by means of grazing-incidence collisions between ion beams and metal surfaces. Residual ions are reflected by applied electric fields. This method can utilize initial ion beams of either O(+) or O2(+) since a very large percentage of molecular oxygen ions are dissociated when they undergo grazing-incidence neutralization. The method of neutralization is applicable to low-energy beams and to all ions. Particular emphasis is on O and N2 beams for simulation of the low Earth orbit space environment. Since the beam is a pure O-neutral beam and since measurements of the interaction of the beam with solid surfaces are made spectroscopically, absolute reaction rates can be determined. The technique permits the beams to be used in conjunction with electron and photon irradiation for studies of synergistic effects. Comparisons of optical spectra of Kapton excited by 2.5-keV O, O(+), and O2(+) show significant differences. Optical spectra of Kapton excited by neutral oxygen beams of less than 1 keV have been recorded.

  20. The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Granados, Carlos [Uppsala Universitet, Institutionen foer Fysik och Astronomi (Sweden); Jefferson Lab, Newport News, VA (United States); Leupold, Stefan; Perotti, Elisabetta [Uppsala Universitet, Institutionen foer Fysik och Astronomi (Sweden)

    2017-06-15

    Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion-Sigma-Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR). (orig.)

  1. Very low energy electron microscopy of graphene flakes.

    Science.gov (United States)

    Mikmeková, E; Bouyanfif, H; Lejeune, M; Müllerová, I; Hovorka, M; Unčovský, M; Frank, L

    2013-08-01

    Commercially available graphene samples are examined by Raman spectroscopy and very low energy scanning transmission electron microscopy. Limited lateral resolution of Raman spectroscopy may produce a Raman spectrum corresponding to a single graphene layer even for flakes that can be identified by very low energy electron microscopy as an aggregate of smaller flakes of various thicknesses. In addition to diagnostics of graphene samples at larger dimensions, their electron transmittance can also be measured at very low energies. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  2. The ISPM experiment for spectral, composition and anistropy measurements of charged particles at low energie

    Science.gov (United States)

    Lanzerotti, L. J.; Gold, R. E.; Anderson, K. A.; Armstrong, T. P.; Lin, R. P.; Krimigis, S. M.; Pick, M.; Roelof, E. C.; Sarris, E. T.; Simnett, G. M.

    1983-01-01

    The Heliosphere Instrument for Spectral, Composition, and Anisotropy at Low Energies (HI-SCALE) designed to measure interplanetary ions and electrons is described. Ions and electrons are detected by five separate solid-state detector telescopes oriented to give complete pitch angle coverage from the spinning spacecraft. Ion elemental abundances are determined by a telescope using a thin front detector element in a three-element telescope. Experiment operation is controlled by a microprocessor-based data system. Inflight calibration is provided by radioactive sources mounted on closable telescope covers. Ion and electron spectral information is determined using broad-energy-range rate channels, and a pulse-height analyzer for more detailed spectra. The instrument weighs 5.775 kg and uses 4.0 W power.

  3. Classification of low energy houses in Danish Building Regulations

    DEFF Research Database (Denmark)

    Rose, Jørgen; Svendsen, Svend

    2005-01-01

    The new Danish Building Regulations (Building Regulations, 2005) introduces the total energy consumption, i.e. energy use for heating, ventilation, cooling and domestic hot water, for buildings as a measure for the energy efficiency of new buildings, i.e. moving away from the former U-value demands....... In addition to the minimum requirements for new buildings, the new Building Regulations also specify requirements for characterizing a building as either low energy building class 1 or low energy building class 2. This paper describes a type-house that is presently being built in Denmark. The type......-house easily meets the requirements for being categorized as a low energy building class 1, and the paper investigates how much U-values can be increased if the type-house were to fulfil the requirements for a low energy building class 2 or a building that just fulfils the minimum demands....

  4. VOYAGER 1 JUP LOW ENERGY CHARGED PARTICLE CALIB. 15MIN

    Data.gov (United States)

    National Aeronautics and Space Administration — THIS DATA SET CONSISTS OF RESAMPLED DATA FROM THE LOW ENERGY CHARGED PARTICLE (LECP) EXPERIMENT ON VOYAGER 1 WHILE THE SPACECRAFT WAS IN THE VICINITY OF JUPITER....

  5. VOYAGER 1 SAT LOW ENERGY CHARGED PARTICLE CALIB. 15MIN

    Data.gov (United States)

    National Aeronautics and Space Administration — THIS DATA SET CONSISTS OF RESAMPLED DATA FROM THE LOW ENERGY CHARGED PARTICLE (LECP) EXPERIMENT ON VOYAGER 1 WHILE THE SPACECRAFT WAS IN THE VICINITY OF SATURN. THIS...

  6. VOYAGER 2 SAT LOW ENERGY CHARGED PARTICLE CALIB. 15MIN

    Data.gov (United States)

    National Aeronautics and Space Administration — THIS DATA SET CONSISTS OF RESAMPLED DATA FROM THE LOW ENERGY CHARGED PARTICLE (LECP) EXPERIMENT ON VOYAGER 2 WHILE THE SPACECRAFT WAS IN THE VICINITY OF SATURN. THIS...

  7. VOYAGER 2 JUP LOW ENERGY CHARGED PARTICLE CALIB. 15MIN

    Data.gov (United States)

    National Aeronautics and Space Administration — THIS DATA SET CONSISTS OF RESAMPLED DATA FROM THE LOW ENERGY CHARGED PARTICLE (LECP) EXPERIMENT ON VOYAGER 2 WHILE THE SPACECRAFT WAS IN THE VICINITY OF JUPITER....

  8. Low energy planes for tilt grain boundaries in gold

    Energy Technology Data Exchange (ETDEWEB)

    Goodhew, P. J.; Tan, T. Y.; Balluffi, R. W.

    1977-05-01

    Thin film bicrystals of gold were annealed to create a large variety of grain boundaries of controlled crystal misorientation. The faceting of these boundaries was studied, and some low-energy boundary planes were identified. Tilt boundaries with a (100) misorientation axis were found to facet more readily than those with a (100) axis. The results were considered in terms of O-lattices and coincident site lattices, but neither of these approaches is able to explain all the observations. Consequently, no simple and general criteria, based on geometrical considerations, were found for the occurrence of grain boundary planes of low energy. A further set of observations relates to the dissociation of some specific high-angle grain boundaries into a twin and another low-energy boundary. Boundaries with a ..sigma..33 coincidence site lattice relationship frequently appear to be characterized by a relatively low energy. 12 figures, 2 tables.

  9. Biological assessments for the low energy demonstration accelerator, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Cross, S.

    1997-03-01

    This report discusses the biological impact to the area around the Los Alamos National Laboratory of the Low Energy Demonstration Accelerator. In particular the impact to the soils, water quality, vegetation, and wildlife are discussed.

  10. Very low energy electron microscopy of graphene flakes

    National Research Council Canada - National Science Library

    MIKMEKOVÁ, E; BOUYANFIF, H; LEJEUNE, M; MÜLLEROVÁ, I; HOVORKA, M; UNČOVSKÝ, M; FRANK, L

    2013-01-01

    .... Limited lateral resolution of Raman spectroscopy may produce a Raman spectrum corresponding to a single graphene layer even for flakes that can be identified by very low energy electron microscopy...

  11. Sedimentary Indicators of Relative Sea-Level Change - Low Energy

    OpenAIRE

    EDWARDS, ROBIN JAMES

    2013-01-01

    PUBLISHED Fine grained sediments associated with low energy conditions have proven to be useful archives of relative sea-level data. Low energy inter-tidal environments, such as saltmarshes and mangroves, are closely linked to the tidal frame. Sediments accumulating in these environments, and the plant and animal remains they contain, can therefore be used to reconstruct the former position of relative sea level in time and space. A number of methodologies employing a combined lithostratig...

  12. The Low Energy Charged Particle /LECP/ experiment on the Voyager spacecraft

    Science.gov (United States)

    Krimigis, S. M.; Bostrom, C. O.; Armstrong, T. P.; Axford, W. I.; Fan, C. Y.; Gloeckler, G.; Lanzerotti, L. J.

    1977-01-01

    The Low Energy Magnetosphere Particle Analyzer (LEMPA) and the Low Energy Particle Telescope (LEPT) on board the Voyager spacecraft are described. The LEMPA has an energy range of about 10 keV to greater than 11 MeV for electrons and about 15 keV to greater than 150 MeV for protons and heavier ions; the LEPT covers a range of about 0.05 to 40 MeV/nucleon with good energy and species resolution. The LEPT and LEMPA subsystems are mounted on a stepping platform which rotates at variable rate through eight angular sectors. Comprehensive measurements of particles in the Jovian, Saturnian, Uranian, and interplanetary environments are expected from the experiment.

  13. Mechanical engineering of a 75-keV proton injector for the Low Energy Demonstration Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Hansborough, L.D.; Hodgkins, D.J.; Meyer, E.A.; Schneider, J.D.; Sherman, J.D.; Stevens, R.R. Jr.; Zaugg, T.J.

    1997-10-01

    A dc injector capable of 75-keV, 110-mA proton beam operation is under development for the Low Energy Demonstration Accelerator (LEDA) project at Los Alamos. The injector uses a dc microwave proton source which has demonstrated 98% beam availability while operating at design parameters. A high-voltage isolation transformer is avoided by locating all ion source power supplies and controls at ground potential. The low-energy beam transport system (LEBT) uses two solenoid focusing and two steering magnets for beam matching and centroid control at the RFQ matchpoint. This paper will discuss proton source microwave window design, H{sub 2} gas flow control, vacuum considerations, LEBT design, and an iris for beam current control.

  14. PIC Simulations in Low Energy Part of PIP-II Proton Linac

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, Gennady

    2014-07-01

    The front end of PIP-II linac is composed of a 30 keV ion source, low energy beam transport line (LEBT), 2.1 MeV radio frequency quadrupole (RFQ), and medium energy beam transport line (MEBT). This configuration is currently being assembled at Fermilab to support a complete systems test. The front end represents the primary technical risk with PIP-II, and so this step will validate the concept and demonstrate that the hardware can meet the specified requirements. SC accelerating cavities right after MEBT require high quality and well defined beam after RFQ to avoid excessive particle losses. In this paper we will present recent progress of beam dynamic study, using CST PIC simulation code, to investigate partial neutralization effect in LEBT, halo and tail formation in RFQ, total emittance growth and beam losses along low energy part of the linac.

  15. Low-energy electron transmission through high aspect ratio Al O nanocapillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Jureta, J.; Víkor, G.

    2009-01-01

    Electron transmission through insulating AlO nanocapillaries of different diameters (40 and 270 nm) and 15 μm length has been investigated for low-energy electrons (2-120 V). The total intensity of transmitted current weakly depends on the incident electron energy and tilt angle defined...... appears to influence significantly only the intensity of the elastic transmission. The present results suggest a more complex nature of low-energy electron transport through insulating nanocapillaries than proposed for positive ions....... with respect to the capillary axis. On the other hand, the intensity of elastically transmitted electrons significantly varies with the alteration of electron energy and tilt angle. In addition, we measured an energy distribution of electrons transmitted both in the straightforward direction and at large tilt...

  16. Recent developments and research projects at the low-energy RI beam facility CRIB

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H., E-mail: yamag@cns.s.u-tokyo.ac.jp [Center for Nuclear Study (CNS), University of Tokyo, RIKEN Campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN Campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubono, S. [RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare, Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502,Japan (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y.K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D.N.; Khiem, L.H.; Duy, N.N. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, HaNoi (Viet Nam)

    2013-12-15

    Highlights: • CRIB is a unique low-energy RI beam separator of the University of Tokyo. • CRIB has been produced various RI beams mainly on the proton-rich side. • The major topics studied at CRIB are resonant scatterings and (alpha, p) reactions. • Strong alpha resonances were observed with {sup 7}Be + alpha resonant scattering. -- Abstract: CRIB (CNS Radioactive Ion Beam separator) is a low-energy RI beam separator at the Center for Nuclear Study (CNS) of the University of Tokyo. An overview of the recent developments and status of CRIB, including a detailed summary of beam parameters, is presented. Studies on proton and α resonant scatterings, direct measurements of (α,p) reactions, and other types of measurements (β-decay lifetimes, etc.) have been performed using RI beams at CRIB, motivated by interests in astrophysical reactions and exotic nuclear structure. Among the studies at CRIB, the measurement of {sup 7}Be + α resonant scattering is discussed.

  17. High-flux electron beams from laser wakefield accelerators driven by petawatt lasers

    Science.gov (United States)

    Zeng, Ming; Tesileanu, Ovidiu

    2017-07-01

    Laser wakefield accelerators (LWFAs) are considered to be one of the most competitive next-generation accelerator candidates. In this paper, we will study the potential high-flux electron beam production of an LWFA driven by petawatt-level laser pulses. In our three-dimensional particle-in-cell simulations, an optimal set of parameters gives ˜ 40 {nC} of charge with 2 {PW} laser power, thus ˜ 400 {kA} of instantaneous current if we assume the electron beam duration is 100 fs. This high flux and its secondary radiation are widely applicable in nuclear and QED physics, industrial imaging, medical and biological studies.

  18. Absolute sputtering yields from solid Ne by low energy He+ and Arq+ (1 >= q >= 6) impact

    Science.gov (United States)

    Fujita, Shinya; Tachibana, Takayuki; Koizumi, Tetsuo; Hirayama, Takato

    2009-04-01

    Absolute sputtering yields from the surface of solid Ne by low energy He+ and Arq+ (1 >= q >= 6) impact are measured. Very large sputtering yields (300 atoms/ion for 1 keV He+ impact, and 3000 atoms/ion for 1keV Ar+ impact) have been observed. A significant dependence of the sputtering yields on the chage state, i.e. the potential energy, of the incident ion for Arq+ has not been observed because it is estimated to be much smaller than that of the kinetic sputtering, which suggests that the mechanism of potential sputtering is similar to those known for the electron- and photon-stimulated desorption processes.

  19. Operating manual for the High Flux Isotope Reactor. Volume I. Description of the facility

    Energy Technology Data Exchange (ETDEWEB)

    1982-09-01

    This volume contains a comprehensive description of the High Flux Isotope Reactor Facility. Its primary purpose is to supplement the detailed operating procedures, providing the reactor operators with background information on the various HFIR systems. The detailed operating procdures are presented in another report.

  20. High flux nanofiltration membranes based on layer-by-layer assembly modified electrospun nanofibrous substrate

    Science.gov (United States)

    Xu, Guo-Rong; Liu, Xiao-Yu; Xu, Jian-Mei; Li, Lu; Su, Hui-Chao; Zhao, He-Li; Feng, Hou-Jun

    2018-03-01

    Herein, high flux nanofiltration (NF) membranes were fabricated by combined procedures of electrospinning, layer-by-layer (LBL) assembly, and phase inversion. The membranes displayed three-dual structure constituted polyether sulfone (PES) coating layer, LBL assembly modified electrospun polyester (PET) nanofibrous mats, and non-woven supports. High flux NF membranes thus prepared are characterized by ultrathin phase inversion layer (∼10 μm) while that of conventional membranes are 100-150 μm, implying that very high flux could be expected. Various factors including electrospinning conditions, chitosan (CHI)/alginate (ALG) concentration, PES concentration, exposed time, coagulating temperature, thermal treatment, and sulfonated poly ether ketone (SPEEK) content were systematically investigated. Structures of the membranes were characterized by field emission scanning electron microscopy (FESEM), mechanical properties test, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and static contact angle measurements. The separation experiments indicated that thus prepared membranes exhibited high flux of as high as ∼75 L m-2 h-1 with Mg SO4 rejection of ∼80%.

  1. Deuterium retention and surface modifications of nanocrystalline tungsten films exposed to high-flux plasma

    NARCIS (Netherlands)

    't Hoen, M.H.J.; Dellasega, D.; Pezzoli, A.; Passoni, M.; Kleyn, A.W.; Zeijlmans van Emmichoven, P.A.

    2015-01-01

    Deuterium retention studies are presented for nanostructured tungsten films exposed to high-flux deuterium plasmas. Thin tungsten films of similar to 1 mu m thickness were deposited with pulsed laser deposition (PLD) on bulk tungsten. Surface modifications were studied with scanning electron

  2. Deuterium retention and surface modifications of nanocrystalline tungsten films exposed to high-flux plasma

    NARCIS (Netherlands)

    Hoen, M. H. J. 't; Dellasega, D.; Pezzoli, A.; Passoni, M.; Kleyn, A. W.; van Emmichoven, P. A. Zeijlma

    2015-01-01

    Abstract Deuterium retention studies are presented for nanostructured tungsten films exposed to high-flux deuterium plasmas. Thin tungsten films of ∼1 μm thickness were deposited with pulsed laser deposition (PLD) on bulk tungsten. Surface modifications were studied with scanning electron

  3. A conceptual high flux reactor design with scope for use in ADS ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 68; Issue 2. A conceptual high flux reactor design with scope for use in ADS applications. Usha Pal V Jagannathan ... A 100 MWt reactor design has been conceived to support flux level of the order of 1015 n/cm2/s in selected flux trap zones. The physics design ...

  4. The Response of the Ionospheric Cusp to the Solar Through Two Perspectives: Low Energy Changed Particle In-Situ Measurements and Low- Energy Neutral Atom Imaging

    Science.gov (United States)

    Coffey, V. N.; Moore, T. E.; Chandler, M. O.; Craven, P. D.

    2000-01-01

    The IMAGE mission provides a new perspective on the study of the response of the magnetosphere/ionosphere system to changing solar wind conditions, particularly the variability of ion outflow. Learning to interpret this new type of data becomes an essential step in the process of melding these results with the wealth of in-situ charged particle observations obtained over the past 25 years. In order to understand how the in-situ data correspond to and contrast with IMAGE results we will perform a conjunctive study of event data from two instruments to shed light on the coupling of the solar wind and ionosphere from these different perspectives. We will use the Low Energy Neutral Atom instrument (LENA) which images energetic neutral atom emissions from upward flowing ionospheric ions and the Thermal Ion Dynamics Instrument (TIDE) on the Polar satellite which measures in-situ ion outflow from 0.3-300 eV. Our primary goal will be to understand how comparing the imaging and in-situ perspectives can aid in the analysis of both data sets.

  5. Coulomb and Nuclear Breakup at Low Energies: Scaling Laws

    Directory of Open Access Journals (Sweden)

    Hussein M. S.

    2013-12-01

    Full Text Available We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.

  6. Light element production by low energy nuclei from massive stars

    Science.gov (United States)

    Vangioni-Flam, E.; Casse, M.; Ramaty, R.

    1997-01-01

    The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.

  7. Low-energy run of Fermilab Electron Cooler's beam generation system

    Energy Technology Data Exchange (ETDEWEB)

    Prost, Lionel; Shemyakin, Alexander; /Fermilab; Fedotov, Alexei; Kewisch, Jorg; /Brookhaven

    2010-08-01

    As a part of a feasibility study of using the Fermilab Electron Cooler for a low-energy Relativistic Heavy Ion Collider (RHIC) run at Brookhaven National Laboratory (BNL), the cooler operation at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main result of the study is that the cooler beam generation system is suitable for BNL needs. In a striking difference with running 4.3 MeV beam, no unprovoked beam recirculation interruptions were observed.

  8. Potential luminosity improvement for low-energy RHIC operation with electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Fedotov,A.

    2009-06-08

    There is a strong interest in heavy-ion RHIC collisions in the energy range below the present RHIC injection energy, which is termed 'low-energy' operation. These collisions will help to answer one of the key questions in the field of QCD about the existence and location of a critical point on the QCD phase diagram. However, luminosity projections are relatively low for the lowest energy points of interest. Luminosity improvement can be provided with RHIC electron cooling at low beam energies. This report summarizes the expected luminosity improvements with electron cooling and various limitations.

  9. High resolution probe of coherence in low-energy charge exchange collisions with oriented targets

    CERN Document Server

    Leredde, A; Cassimi, A; Hennecart, D; Pons, B

    2013-01-01

    The trapping lasers of a magneto-optical trap (MOT) are used to bring Rb atoms into well defined oriented states. Coupled to recoil-ion momentum spectroscopy (RIMS), this yields a unique MOTRIMS setup which is able to probe scattering dynamics, including their coherence features, with unprecedented resolution. This technique is applied to the low-energy charge exchange processes Na$^+$+Rb($5p_{\\pm 1}$) $\\rightarrow$ Na($3p,4s$)+Rb$^+$. The measurements reveal detailed features of the collisional interaction which are employed to improve the theoretical description. All of this enables to gauge the reliability of intuitive pictures predicting the most likely capture transitions.

  10. Direct observation of pure one-electron capture from the target inner shell in low-energy p+Na collisions

    NARCIS (Netherlands)

    Knoop, S; Morgenstern, R; Hoekstra, R

    2004-01-01

    One-electron removal in the p+Na collision system has been investigated at low energy (4-25 keV) by means of recoil ion momentum spectroscopy. The focus will be on the contribution of one-electron capture from the Na 2p inner shell into the hydrogen ground state, thereby leaving the Na+ target ion

  11. Procuring low-energy design and consulting services

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    This report presents information which aids in the design of low energy building elements. The proven strategies can dramatically reduce a building`s energy consumption for little or no added cost while improving it`s comfort, economy, and environmental performance.

  12. Compact Measurement Station for Low Energy Proton Beams

    CERN Document Server

    Yildiz, H.

    2017-02-24

    A compact, remote controlled, cost efficient diagnostic station has been developed to measure the charge, the profile and the emittance for low energy proton beams. It has been installed and tested in the proton beam line of the Project Prometheus at SANAEM of the Turkish Atomic Energy Authority.

  13. Low-energy particle radiation environment at synchronous altitude

    Science.gov (United States)

    Shelley, E. G.; Lens, S. K.

    1972-01-01

    The degradation of thermal control coatings of satellites due to the effects of low energy charged particles in the space environment is discussed. Data obtained from ATS-5 satellite measurement of proton and electron fluxes are presented. The variations in electron density, proton density, and magnetic activity are presented to show correlations which exist between these space factors.

  14. Polarization observables in low-energy antiproton-proton scattering

    NARCIS (Netherlands)

    Zhou, Daren; Timmermans, Rob G. E.

    2013-01-01

    We investigate the polarization parameters in low-energy antiproton-proton elastic ((p) over barp -> (p) over barp) and charge-exchange ((p) over barp -> (n) over barn) scattering. The predictions for unmeasured observables are based on our new energy-dependent partial-wave analysis of all

  15. Low-energy buildings on mainstream market terms

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Elle, Morten; Hoffmann, Birgitte

    2008-01-01

    implementation of strict energy performance requirements in mainstream building. The paper describes how the municipality of Egedal experienced a collapse in regulation for low-energy buildings and what struggles it had to take on in order to convince the mainstream building industry and their customers...

  16. Low energy electron imaging using Medipix 2 detector

    NARCIS (Netherlands)

    Sikharulidze, I.; van Gastel, Raoul; Schramm, S.; Abrahams, J.P.; Poelsema, Bene; Tromp, R.M.; van der Molen, S.J.

    2011-01-01

    Low Energy Electron Microscopy (LEEM) and Photo-Emission Electron Microscopy (PEEM) predominantly use a combination of microchannel plate (MCP), phosphor screen and optical camera to record images formed by 10–20 keV electrons. We have tested the performance of a LEEM/PEEM instrument with a Medipix2

  17. Working group report: Low energy and flavour physics

    Indian Academy of Sciences (India)

    B physics, perturbative quantum chromodynamics. PACS No. 13.25.Hw. 1. Introduction. The activities of the 'low energy and flavour physics' working group at WHEPP-8 were almost exclusively in the area of B physics. Given that data from the B- factories are currently challenging the predictions of theoretical models as well ...

  18. Low-energy nuclear reactions with double-solenoid-based ...

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... The University of Notre Dame, USA (Becchetti et al, Nucl. Instrum. Methods Res. A505, 377 (2003)) and later the University of São Paulo, Brazil (Lichtenthaler et al, Eur. Phys. J. A25, S-01, 733 (2005)) adopted a system based on superconducting solenoids to produce low-energy radioactive nuclear beams.

  19. A primer for electroweak induced low-energy nuclear reactions

    Indian Academy of Sciences (India)

    Abstract. Under special circumstances, electromagnetic and weak interactions can in- duce low-energy nuclear reactions to occur with observable rates for a variety of processes. A common element in all these applications is that the electromagnetic energy stored in many relatively slow-moving electrons can – under ...

  20. Performance of the Low-energy House in Sisimiut

    DEFF Research Database (Denmark)

    Rode, Carsten; Kragh, Jesper; Borchersen, Egil

    2009-01-01

    A low-energy house was built in Sisimiut, Greenland in 2004-05 and since its inauguration in April 2005, its performance and operation have been object of study for researchers and students. The house is characterised by a highly insulated building envelope, advanced windows and a ventilation sys...

  1. Utilization of low-energy electron accelerators in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Cheol [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2003-02-01

    There are more than 20 electron accelerators in Korea. Most of those are installed in factories for heat-resistant cables, heat-shrinkable cables, radial tires, foams, tube/ films, curing, etc. Four low-energy electron accelerators are in operation for research purposes such as polymer modification, purification of flue gas, waste water treatment, modification of semiconductor characteristics, etc. (author)

  2. Effects of disability-associated low energy expenditure deconditioning syndrome.

    Science.gov (United States)

    Rimmer, James H; Schiller, William; Chen, Ming-De

    2012-01-01

    People with neuromuscular disabilities have high rates of sedentary behavior predisposing them to severe deconditioning and significant health risk. We describe this as disability-associated low energy expenditure deconditioning syndrome and propose new approaches for promoting light-to-moderate intensity physical activity in people with disabilities.

  3. Low energy neutral beam production by laser vaporization of metals

    OpenAIRE

    Breton, C.; De Michelis, C.; Hecq, W.; Mattioli, M.

    1980-01-01

    We have quantitatively studied the production of low energy (0.1-10 eV) metal neutral beams by laser vaporization of thin metal foils. For the experimental geometry available on the TFR tokamak, this technique results in the injection of 1015 neutrals in a time of ∼ 300 μs.

  4. Low-energy CZT detector array for the ASIM mission

    DEFF Research Database (Denmark)

    Cenkeramaddi, Linga Reddy; Genov, Georgi; Kohfeldt, Anja

    2012-01-01

    In this article we introduce the low-energy CZT (CdZnTe) 16 384-pixel detector array on-board the Atmosphere Space Interaction Monitor (ASIM), funded by the European Space Agency. This detector is a part of the larger Modular X-and Gamma-ray sensor (MXGS). The CZT detector array is sensitive...

  5. Nuclear phenomena in low-energy nuclear reaction research.

    Science.gov (United States)

    Krivit, Steven B

    2013-09-01

    This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.

  6. Mirrored low-energy channel for the MiniXRD

    Energy Technology Data Exchange (ETDEWEB)

    Dutra, Eric [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); MacNeil, Lawrence [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Raphaelian, Mark [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Compton, Steve; Jacoby, Barry

    2015-10-08

    X-ray Diodes (XRDs) are currently used for spectroscopic measurements, measuring X-ray flux, and estimating spectral shape of the VUV to soft X-ray spectrum. A niche exists for an inexpensive, robust X-ray diode that can be used for experiments in hostile environments on multiple platforms, including explosively driven experiments that have the potential for destroying the diode during the experiment. A multiple channel stacked filtered array was developed with a small field of view where a wider parallel array could not be used, but filtered channels for energies lower than 1000 eV were too fragile to deploy under normal conditions. To achieve both the robustness and the required low-energy detection ability, the researchers designed a small low-energy mirrored channel with a spectral sensitivity from 30 to 1000 eV. The stacked MiniXRD X-ray diode system design incorporates the mirrored low-energy channel on the front of the stacked filtered channels to allow the system to work within a small field of view. We will present results that demonstrate this is a promising solution for low-energy spectrum measurements.

  7. Positron impact ionization of atomic hydrogen at low energies

    Indian Academy of Sciences (India)

    energies. K CHAKRABARTI. Department of Mathematics, Scottish Church College, 1 & 3 Urquhart Square, Calcutta 700 006,. India. MS received 26 June 2000. Abstract. Low energy positron impact ionization of atomic hydrogen is studies theoretically using the hyperspherical partial wave method of Das [1] in constant ΘЅѕ, ...

  8. Positron impact ionization of atomic hydrogen at low energies

    Indian Academy of Sciences (India)

    Low energy positron impact ionization of atomic hydrogen is studies theoretically using the hyperspherical partial wave method of Das [1] in constant 12, equal energy sharing geometry. The TDCS reveal considerable differences in physics compared to electron impact ionization under the same geometry.

  9. Scattered ionizing radiations from low-energy focus plasma and ...

    Indian Academy of Sciences (India)

    Scattered ionizing radiations from low-energy focus plasma and radiation dosimetery assessment. G M EL-ARAGI∗, M A AYAD, M A EL-KOLALY and .... 4000 system is in coaxial connection with a computer system which has a special software program for resolving TL-data and assorting the resolved data in classified files.

  10. Low energy beam line at the AGOR facility

    NARCIS (Netherlands)

    Toprek, D; Formanoy, [No Value; Brandenburg, S

    The origin of the low transmission through the low energy beam line between the electron cyclotron resonance source and the AGOR cyclotron has been investigated. Measurements of beam size and emittance, determined with the "varying quadrupole method," are compared with calculations including fringe

  11. Transport theory and low energy properties of colour superconductors

    CERN Document Server

    Litim, Daniel F

    2002-01-01

    The one-loop polarisation tensor and the propagation of ``in-medium'' photons of colour superconductors in the 2SC and CFL phase is discussed. For a study of thermal corrections to the low energy effective theory in the 2SC phase, a classical transport theory for fermionic quasiparticles is invoked.

  12. A primer for electroweak induced low-energy nuclear reactions

    Indian Academy of Sciences (India)

    Under special circumstances, electromagnetic and weak interactions can induce low-energy nuclear reactions to occur with observable rates for a variety of processes. A common element in all these applications is that the electromagnetic energy stored in many relatively slow-moving electrons can – under appropriate ...

  13. Low Energy Defibrillation in Human Cardiac Tissue: A Simulation Study

    Science.gov (United States)

    Morgan, Stuart W.; Plank, Gernot; Biktasheva, Irina V.; Biktashev, Vadim N.

    2009-02-01

    We aim to assess the effectiveness of feedback controlled resonant drift pacing as a method for low energy defibrillation. Antitachycardia pacing is the only low energy defibrillation approach to have gained clinical significance, but it is still suboptimal. Low energy defibrillation would avoid adverse side effects associated with high voltage shocks and allow the application of ICD therapy where it is not tolerated today. We present results of computer simulations of a bidomain model of cardiac tissue with human atrial ionic kinetics. Re-entry was initiated and low energy shocks were applied with the same period as the re-entry, using feedback to maintain resonance. We demonstrate that such stimulation can move the core of re-entrant patterns, in the direction depending on location of electrodes and a time delay in the feedback. Termination of re-entry is achieved with shock strength one order of magnitude weaker than in conventional single-shock defibrillation. We conclude that resonant drift pacing can terminate re-entry at a fraction of the shock strength currently used for defibrillation and can potentially work where antitachycardia pacing fails, due to the feedback mechanisms. Success depends on a number of details which these numerical simulations have uncovered. \\emph{Keywords} Re-entry; Bidomain model; Resonant drift; ICD; Defibrillation; Antitachycardia pacing; Feedback.

  14. Design of low energy bunch compressors with space charge effects

    Directory of Open Access Journals (Sweden)

    A. He

    2015-01-01

    Full Text Available In this paper, we explore a method to manipulate low energy electron bunches in a space charge dominated regime, and we use this method to design low energy linac bunch compressors to compress electron bunches in a space charge dominated regime. In the method, we use the space charge effects instead of avoiding them; i.e., we use the space charge forces to generate the required energy chirp instead of the ordinary method which uses the rf accelerating system to generate the chirp. We redefine the concepts of the dispersion function and beta functions in a space charge dominated regime to guide the optimization. Using this method, we study the low energy (5–22 MeV linac bunch compressor design to produce short (∼150  fs and small size (∼30  μm bunches for the electron beam slicing project. The low energy linac bunch compressors work in a space charge dominated regime, and the bunches at the downstream of the gun have a negative energy chirp due to the space charge effects. To provide compression for the negative energy chirped bunch, we design a positive R_{56} dispersive section using a four-dipole chicane with several quadrupole magnets. We have designed low energy linac bunch compressors with different photocathode rf guns. For example, one linac bunch compressor with the BNL photocathode electron rf gun has achieved a low energy bunch with the 166 fs rms bunch length, 28 and 31  μm rms beam size in the vertical and horizontal directions, respectively, at 5 MeV with 50 pC charge. Another example with LBNL’s very-high frequency gun has achieved a low energy bunch with the 128 fs rms bunch length, 42 and 25  μm rms beam size in the vertical and horizontal directions, respectively, at 22 MeV with 200 pC charge.

  15. FOEHN: The critical experiment for the Franco-German High Flux Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Scharmer, K.; Eckert, H. G. [Kernforschungszentrum Karlsruhe GmbH (Germany)

    1991-01-01

    A critical experiment for the Franco-German High Flux Reactor was carried out in the French reactor EOLE (CEN Cadarache). The purpose of the experiment was to check the calculation methods in a realistic geometry and to measure effects that can only be calculated imprecisely (e.g. beam hole effects). The structure of the experiment and the measurement and calculation methods are described. A detailed comparison between theoretical and experimental results was performed. 30 refs., 105 figs.

  16. Influence of high flux hydrogen-plasma exposure on the thermal shock induced crack formation in tungsten

    NARCIS (Netherlands)

    Wirtz, M.; Linke, J.; Pintsuk, G.; Rapp, J.; Wright, G. M.

    2012-01-01

    The influence of high flux hydrogen-plasma on the thermal shock behaviour of tungsten was investigated in a combined experiment using the linear plasma device Pilot-PSI and the electron beam facility JUDITH 1. Tungsten targets were exposed to high flux hydrogen plasma, cyclic thermal shock tests and

  17. How to Succeed in Low-Energy Housing—Path Creation Analysis of Low-Energy Innovation Projects

    Directory of Open Access Journals (Sweden)

    Pia Pässilä

    2015-07-01

    Full Text Available The low-energy and the nearly zero-energy buildings trend is calling for radical new innovations from the construction industry. This study uses path creation theory to examine two innovation concepts for low-energy housing in Northern Europe with contrasting outcomes—with one being an apparent market success and the other a disappointment. The results highlight two issues behind the success, one of a systemic nature and the other concerning innovation management. First, the development of energy efficiency regulations and the dominant technological trajectory regarding low-energy houses are interdependent. However, it seems that while supporting the trajectory of the innovation developed in the first case, regulators created virtually insurmountable cognitive and normative obstacles to finding alternative technological pathways. Second, the significance of proof of concepts for new innovations cannot be underestimated. The importance of a pilot project rests not only on showcasing and testing the technology, but also on its ability to increase political support, investments, and public awareness. The study implies that low-energy construction seems to be the next great challenge, one where genuine co-operation between the industry, public authorities and academia is a prerequisite for success.

  18. Charge neutralized low energy beam transport at Brookhaven 200 MeV linac.

    Science.gov (United States)

    Raparia, D; Alessi, J; Atoian, G; Zelenski, A

    2016-02-01

    The H(-) magnetron source provides about 100 mA H(-) beam to be match into the radio-frequency quadrupole accelerator. As H(-) beam traverses through low energy transport, it ionizes the residual gas and electrons are repelled and positive ions are trapped in the beam, due to negative potential of the beam, providing charge neutralization for the H(-) beam. The neutralization time for the critical density depends upon the background gas and its pressure. Critical density for xenon gas at 35 keV is about 43 times smaller than that of hydrogen and stripping cross section is only 5 times than that of hydrogen gas. We are using xenon gas to reduce neutralization time and to improve transmission through the 200 MeV linac. We are also using pulse nitrogen gas to improve transmission and stability of polarized H(-) beam from optically pumped polarized ion source.

  19. Low-Energy Collisions of Protonated Enantiopure Amino Acids with Chiral Target Gases

    Science.gov (United States)

    Kulyk, K.; Rebrov, O.; Ryding, M.; Thomas, R. D.; Uggerud, E.; Larsson, M.

    2017-12-01

    Here we report on the gas-phase interactions between protonated enantiopure amino acids ( l- and d-enantiomers of Met, Phe, and Trp) and chiral target gases [( R)- and ( S)-2-butanol, and ( S)-1-phenylethanol] in 0.1-10.0 eV low-energy collisions. Two major processes are seen to occur over this collision energy regime, collision-induced dissociation and ion-molecule complex formation. Both processes were found to be independent of the stereo-chemical composition of the interacting ions and targets. These data shed light on the currently debated mechanisms of gas-phase chiral selectivity by demonstrating the inapplicability of the three-point model to these interactions, at least under single collision conditions. [Figure not available: see fulltext.

  20. Genealogy of gas cells for low-energy RI-beam production

    Energy Technology Data Exchange (ETDEWEB)

    Wada, Michiharu, E-mail: mw@riken.jp

    2013-12-15

    Highlights: • In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. • The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. • Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique. -- Abstract: In order to overcome serious limitations in the universality of the traditional isotope separator on-line technique, various endeavors have been made on gas catcher cells for converting relativistic RI-beams from in-flight separators to low-energy RI-beams. The origin of the gas catcher is found in the IGISOL (Ion guide isotope separator on-line) technique. Many developments have been made over the years to overcome the various difficulties and drawbacks found in the IGISOL technique.

  1. Space charge compensation on the low energy beam transport of Linac4

    CERN Document Server

    AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

    Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

  2. Beam simulation studies of ECR beam extraction and low energy beam transport for FRIB.

    Science.gov (United States)

    Ren, Haitao; Pozdeyev, Eduard; Lund, Steven M; Machicoane, Guillaume; Wu, Xiaoyu; Morgan, Glenn

    2016-02-01

    To meet the beam power requirements of 400 kW at the fragmentation target for facility for Rare Isotope Beams (FRIB), simultaneous acceleration of two-charge states should be used for heavier ions. These intense multi-charged ion beams will be produced by a 28 GHz electron cyclotron resonance (ECR) ion source at a high voltage of 35 kV. After extraction, the ion beam will be pre-accelerated to 12 keV/u with a 50 kV platform, transported down to an achromatic charge state selection (CSS) system followed by a vertical transport line, and then injected into a radio frequency quadrupole accelerator. The TRACK code developed at ANL is used to perform the simulations of the ECR beam extraction and low energy beam transport for FRIB. In this study, we include the magnetic field of ECR ion source into simulations. Different initial beam conditions as well as different space charge neutralization levels are tested for the ECR beamline. The beam loss in CSS system and the corresponding protective measures are discussed. The detailed results about the beam dynamic simulation and beam loss in CSS system will be presented in this paper.

  3. A Low Energy Intelligent Clustering Protocol for Wireless Sensor Network

    DEFF Research Database (Denmark)

    Li, Qiao; Cui, Lingguo; Zhang, Baihai

    2010-01-01

    LEACH (low-energy adaptive clustering hierarchy) is a well-known self-organizing, adaptive clustering protocol of wireless sensor networks. However it has some shortcomings when it faces such problems as the cluster construction and energy management. In this paper, LEICP (low energy intelligent......-head as the next hop for delivering the messages or to send the data to the base station directly, using Dijkstra algorithm to compute an optimal path. The performance of LEICP is compared with that of LEACH. Simulation results demonstrate that LEICP can prolong the lifetime of the sensor network by about 62...... clustering protocol), an improvement of the LEACH protocol is proposed to overcome the shortcomings of LEACH. LEICP aims at balancing the energy consumption in every cluster and prolonging the network lifetime. A fitness function is defined to balance the energy consumption in every cluster according...

  4. European national strategies to move towards very low energy buildings

    DEFF Research Database (Denmark)

    Wittchen, Kim Bjarne; Thomsen, Kirsten Engelund

    of official subsidies or via private investment organisations. Another possibility is lower taxes for low energy buildings or the introduction of CO2 taxes. Furthermore mandatory certification schemes are expected to promote very low energy buildings by introduction of grades restricted to buildings with very....... A strategy for improved energy efficiency of existing buildings is a necessity if the energy consumption is to be reduced significantly over a limited period of time. The life time of buildings ranges from 50 to 100 years and improvement of the existing building stock will thus have much higher impact than...... is an effective instrument to achieve highly energy efficient buildings, as well as a valuable tool and guideline for the construction sector....

  5. Radiation processing of liquid with low energy electron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, Keizo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-02-01

    Radiation induced emulsion polymerization, radiation vulcanization of NR latex (RVNRL) and radiation degradation of natural polymers were selected and reviewed as the radiation processing of liquid. The characteristic of high dose rate emulsion polymerization is the occurrence of cationic polymerization. Thus, it can be used for the production of new materials that cannot be obtained by radical polymerization. A potential application will be production of polymer emulsion that can be used as water-borne UV/EB curing resins. The technology of RVNRL by {gamma}-ray has been commercialized. RVNRL with low energy electron accelerator is under development for further vulcanization cost reduction. Vessel type irradiator will be favorable for industrial application. Radiation degradation of polysaccharides is an emerging and promising area of radiation processing. However, strict cost comparison between liquid irradiation with low energy EB and state irradiation with {gamma}-ray should be carried out. (author)

  6. Ionization cooling in a low-energy proton storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Neuffer, David V.; /Fermilab

    2006-03-01

    At the FFAG05 meeting, Mori and Okabe presented a scenario in which the lifetime of protons in a low-energy storage ring ({approx}10 MeV) is extended by energy-loss in a wedge foil, and this enables greater neutron production from the foil. The lifetime extension is due to the cooling effect of this energy loss. We have previously analyzed ionization cooling for muons at optimal cooling energies. The same equations, with appropriate adaptations, can be used to analyze the dynamic situation for proton-material interactions at low energies. In this note we discuss this extension and calculate cooling and heating effects at these very different parameters. The ring could provide a practical application of ionization cooling methods.

  7. Energy performance of the low-energy house in Greenland

    DEFF Research Database (Denmark)

    Kragh, Jesper; Svendsen, Svend

    2005-01-01

    The object of the low-energy house in Sisimiut in Greenland was to build a house with an energy consumption less than 80 kWh/m² corresponding to half the energy frame of the coming building code. Therefore the focus in this project has been on large insulation thicknesses, windows with high net...... energy gain, efficient ventilation system with heat recovery and solar heating. In this paper the results of a calculation of the energy consumption of low-energy house is presented. The calculation was done using the program BSim2002 [1] and a new weather test reference year based on climatic data...... by ventilation heat recovery (90% efficiency) specially designed for arctic conditions, by using thicker insulation in walls (300 mm) and roof/floor (350 mm), and by using solar hot water heating (3250 kWh/year). The building is intended to enhance sustainability in the building sector in Greenland....

  8. Low-energy potential scattering in two and three dimensions

    CERN Document Server

    Khuri, N.N.; Richard, Jean-Marc; Wu, Tai Tsun

    2009-01-01

    Conditions are established for the existence of a scattering length and an effective range in the low-energy expansion of the S-wave phase-shift of a central potential in two and three dimensions. The behavior of the phase-shift as a function of the momentum is also derived for longer-range power-law potentials which do not fulfill these conditions.

  9. Selected Papers on Low-Energy Antiprotons and Possible Applications

    Energy Technology Data Exchange (ETDEWEB)

    Noble, Robert [Fermilab

    1998-09-19

    The only realistic means by which to create a facility at Fermilab to produce large amounts of low energy antiprotons is to use resources which already exist. There is simply too little money and manpower at this point in time to generate new accelerators on a time scale before the turn of the century. Therefore, innovation is required to modify existing equipment to provide the services required by experimenters.

  10. Low Energy Supersymmetry from the Heterotic String Landscape

    CERN Document Server

    Lebedev, O; Raby, S; Ramos-Sanchez, S; Ratz, M; Vaudrevange, P K S; Wingerter, A; Lebedev, Oleg; Nilles, Hans-Peter; Raby, Stuart; Ramos-Sanchez, Saul; Ratz, Michael; Vaudrevange, Patrick K. S.; Wingerter, Akin

    2007-01-01

    We study possible correlations between properties of the observable and hidden sectors in heterotic string theory. Specifically, we analyze the case of the Z6-II orbifold compactification which produces a significant number of models with the spectrum of the supersymmetric standard model. We find that requiring realistic features does affect the hidden sector such that hidden sector gauge group factors SU(4) and SO(8) are favoured. In the context of gaugino condensation, this implies low energy supersymmetry breaking.

  11. Low energy hadronic contribution to the QED vacuum polarization

    CERN Document Server

    Burkhardt, H

    2005-01-01

    Recent improvements in the low energy e+e- annihilation data and their influence on the determination of the hadronic contribution to the running of the QED fine structure constant at m_Z are discussed. Using CMD-2 and KLOE measurements in the rho region we obtain Delta alpha(5)_had(s) = 0.02758 +/- 0.00035 at s = m_Z^2.

  12. Liquid noble gas detectors for low energy particle physics

    OpenAIRE

    Chepel, Vitaly; Araújo, Henrique

    2012-01-01

    We review the current status of liquid noble gas radiation detectors with energy threshold in the keV range, wich are of interest for direct dark matter searches, measurement of coherent neutrino scattering and other low energy particle physics experiments. Emphasis is given to the operation principles and the most important instrumentation aspects of these detectors, principally of those operated in the double-phase mode. Recent technological advances and relevant developments in photon dete...

  13. Treatment of surfaces with low-energy electrons

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Mikmeková, Eliška; Lejeune, M.

    2017-01-01

    Roč. 407, JUN 15 (2017), s. 105-108 ISSN 0169-4332 R&D Projects: GA TA ČR(CZ) TE01020118; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : Low-energy electrons * Electron beam induced release * Graphene * Ultimate cleaning of surfaces Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.387, year: 2016

  14. Proceedings of RIKEN BNL Resarch Center Workshop: Fluctuations, Correlations and RHIC Low Energy Runs

    Energy Technology Data Exchange (ETDEWEB)

    Karsch, F.; Kojo, T.; Mukherjee, S.; Stephanov, M.; Xu, N.

    2011-10-27

    Most of our visible universe is made up of hadronic matter. Quantum Chromodynamics (QCD) is the theory of strong interaction that describes the hadronic matter. However, QCD predicts that at high enough temperatures and/or densities ordinary hadronic matter ceases to exist and a new form of matter is created, the so-called Quark Gluon Plasma (QGP). Non-perturbative lattice QCD simulations shows that for high temperature and small densities the transition from the hadronic to the QCD matter is not an actual phase transition, rather it takes place via a rapid crossover. On the other hand, it is generally believed that at zero temperature and high densities such a transition is an actual first order phase transition. Thus, in the temperature-density phase diagram of QCD, the first order phase transition line emanating from the zero temperature high density region ends at some higher temperature where the transition becomes a crossover. The point at which the first order transition line turns into a crossover is a second order phase transition point belonging to three dimensional Ising universality class. This point is known as the QCD Critical End Point (CEP). For the last couple of years the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been performing experiments at lower energies in search of the elusive QCD CEP. In general critical behaviors are manifested through appearance of long range correlations and increasing fluctuations associated with the presence of mass-less modes in the vicinity of a second order phase transition. Experimental signatures of the CEP are likely to be found in observables related to fluctuations and correlations. Thus, one of the major focuses of the RHIC low energy scan program is to measure various experimental observables connected to fluctuations and correlations. On the other hand, with the start of the RHIC low energy scan program, a flurry of activities are taking place to provide solid theoretical

  15. Luminescence model with quantum impact parameter for low energies; Modelo de luminiscencia con parametro de impacto cuantico para bajas energias

    Energy Technology Data Exchange (ETDEWEB)

    Cruz G, H.S.; Michaelian, K.; Galindo U, S.; Martinez D, A.; Belmont M, E. [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico- Toluca Km. 36.5, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The analytical model of induced light production in scintillator materials by energetic ions proposed by Michaelian and Menchaca (M-M) adjusts very well the luminescence substance data in a wide energy interval of the incident ions (10-100 MeV). However at low energies, that is, under to 10 MeV, the experimental deviations of the predictions of M-M model, show that the causes may be certain physical effects, all they important at low energies, which were not considered. We have modified lightly the M-M model using the basic fact that the Quantum mechanics gives to a different limit for the quantum impact parameter instead of the classic approximation. (Author)

  16. A Low energy neutrino factory for large theta(13)

    Energy Technology Data Exchange (ETDEWEB)

    Geer, Steve; Mena, Olga; /Fermilab /Rome U. /INFN, Rome; Pascoli, Silvia; /Durham U., IPPP

    2007-01-01

    If the value of {theta}{sub 13} is within the reach of the upcoming generation of long-baseline experiments, T2K and NOvA, they show that a low-energy neutrino factory, with peak energy in the few GeV range, would provide a sensitive tool to explore CP-violation and the neutrino mass hierarchy. They consider baselines with typical length 1000-1500 km. The unique performance of the low energy neutrino factory is due to the rich neutrino oscillation pattern at energies between 1 and 4 GeV at baselines {Omicron}(1000) km. They perform both a semi-analytical study of the sensitivities and a numerical analysis to explore how well this setup can measure {theta}{sub 13}, CP-violation, and determine the type of mass hierarchy and the {theta}{sub 23} quadrant. A low energy neutrino factory provides a powerful tool to resolve ambiguities and make precise parameter determinations, for both large and fairly small values of the mixing parameter {theta}{sub 13}.

  17. Imaging and background in low-energy gamma ray astronomy

    Science.gov (United States)

    Lei, Fan

    The current status of low energy gamma ray astronomy is reviewed and the conclusion drawn that the next generation of low energy gamma ray telescopes will require high sensitivity, good timing, and spectral resolution. High angular resolution imaging capability is also considered essential. The imaging of low energy gamma rays is hampered by the difficulties encountered in developing high resolution position sensitive detectors. To this end, an improved Rotation Modulation Collimator (RMC) imaging technique, the phoswich multi-pitch RMC, is discussed. This imaging method employs currently available detector and pulse-shape discrimination techniques and is capable of producing images with an angular resolution which is comparable with that of the Coded Aperture Mask (CAM) imaging techniques. The imaging property of this new technique is studied. A comparison of three of the main imaging techniques used in low energy gamma ray astronomy, CAM, Fourier Transform Collimator, and RMC, is performed in terms of both theoretical performances and simulated imaging of the Galactic Center region. A realistic assessment of the possible applications of these three techniques to different types of astronomical Observations is also given. The atmospheric gamma ray radiation was measured by a number of balloon and satellite-borne instruments. A model of this radiation is developed based on the data as measured by a Compton telescope designed by the Max-Planck group. Emission spectra, as predicted by the model, are compared with various observed data, both inside and outside the atmosphere. The sources of background noise in low energy gamma ray telescopes are discussed. A comprehensive model of the background sources is developed and a generalized simulation program is presented which uses a combination of Monte Carlo methods and empirical calculations. Photon, proton, and neutron induced backgrounds are all considered as well as the effects of spacecraft and orbit. The model is

  18. Evaluation of a plane-parallel ionization chamber for low-energy radiotherapy beams

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana Paula; Neves, Lucio Pereira; Santos, William de Souza; Caldas, Linda V.E., E-mail: aperini@ipen.br, E-mail: lpneves@ipen.br, E-mail: wssantos@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    A plane-parallel ionization chamber, with a sensitive volume of 6.3 cm{sup 3}, developed at the Calibration Laboratory of IPEN (LCI), was utilized to verify the possibility of its application in low-energy X-ray beam qualities for radiotherapy (T-qualities). This homemade ion chamber was manufactured using polymethyl methacrylate (PMMA) coated with graphite, and co-axial cables. In order to evaluate the performance of this ionization chamber, some characterization tests were performed: short- and medium-term stability, leakage current, saturation, ion collection efficiency, polarity effect and linearity of response. The maximum value obtained in the short-term stability test was 0.2%, in accordance with the limit value of 0.3% provided by the IEC 60731 standard. The saturation curve was obtained varying the applied voltage from -400 V to +400 V, in steps of 50 V, using the charge collecting time of 20 s. From the saturation curve two other characteristics were analyzed: the polarity effect and the ion collection efficiency, with results within the international recommendations. The leakage current of the ionization chamber was measured in time intervals of 20 minutes, before and after its irradiations, and all the results obtained were in agreement with the IEC 60731 standard. The linearity of response was verified utilizing the T-50(b) radiation quality, and the ionization chamber was exposed to different air kerma rates. The response of the ionization chamber presented a linear behavior. Therefore, all results were considered satisfactory, within international recommendations, indicating that this homemade ionization chamber presents potential routine use in dosimetry of low-energy radiotherapy beams. (author)

  19. Design of the low energy beam transport line between CARIBU and the EBIS charge breeder

    Energy Technology Data Exchange (ETDEWEB)

    Perry, A., E-mail: aperry4@hawk.iit.edu [Argonne National Laboratory, Argonne, IL 60439, USA and Illinois Institute of Technology, Chicago, IL 60616 (United States); Ostroumov, P. N.; Barcikowski, A.; Dickerson, C.; Kondrashev, S. A.; Mustapha, B.; Savard, G. [Argonne National Laboratory, Argonne, IL 60439 (United States)

    2015-01-09

    An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at ATLAS. The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and improve the purity of reaccelerated radioactive ion beams. The EBIS-CB is in the final stage of off-line commissioning. Currently, we are developing a low energy beam transport (LEBT) system to transfer CARIBU beams to the EBIS-CB. As was originally planned, an RFQ cooler-buncher will precede the EBIS-CB. Recently, it was decided to include a multi-reflection time-of-flight (MR-TOF) mass-spectrometer following the RFQ. MR-TOF is a relatively new technology used to purify beams with a mass-resolving power up to 3×10{sup 5} as was demonstrated in experiments at CERN/ISOLDE. Very high purity singly-charged radioactive ion beams will be injected into the EBIS for charge breeding and due to its inherent properties, the EBIS-CB will maintain the purity of the charge bred beams. Possible contamination of residual gas ions will be greatly suppressed by achieving ultra-high vacuum in the EBIS trap. This paper will present and discuss the design of the LEBT and the overall integration of the EBIS-CB into ATLAS.

  20. High flux, narrow bandwidth compton light sources via extended laser-electron interactions

    Science.gov (United States)

    Barty, V P

    2015-01-13

    New configurations of lasers and electron beams efficiently and robustly produce high flux beams of bright, tunable, polarized quasi-monoenergetic x-rays and gamma-rays via laser-Compton scattering. Specifically, the use of long-duration, pulsed lasers and closely-spaced, low-charge and low emittance bunches of electron beams increase the spectral flux of the Compton-scattered x-rays and gamma rays, increase efficiency of the laser-electron interaction and significantly reduce the overall complexity of Compton based light sources.

  1. Engineering and erection of a 300kW high-flux solar simulator

    Science.gov (United States)

    Wieghardt, Kai; Laaber, Dmitrij; Hilger, Patrick; Dohmen, Volkmar; Funken, Karl-Heinz; Hoffschmidt, Bernhard

    2017-06-01

    German Aerospace Center (DLR) is currently constructing a new high-flux solar simulator synlight which shall be commissioned in late 2016. The new facility will provide three separately operated experimental spaces with expected radiant powers of about 300kW / 240kW / 240kW respectively. synlight was presented to the public for the first time at SolarPACES 2015 [1]. Its engineering and erection is running according to plan. The current presentation reports about the engineering and the ongoing erection of the novel facility, and gives an outlook on its new level of possibilities for solar testing and qualification.

  2. Developing effective rockfall protection barriers for low energy impacts

    Science.gov (United States)

    Mentani, Alessio; Giacomini, Anna; Buzzi, Olivier; Govoni, Laura; Gottardi, Guido; Fityus, Stephen

    2016-04-01

    Recently, important progresses have been made towards the development of high capacity rockfall barriers (100 kJ - 8000 kJ). The interest of researchers and practitioners is now turning to the development of fences of minor capacity, whose use becomes essential in areas where rockfall events generally have low intensity and the use of high capacity barriers would be accompanied by excessive costs and high environmental impact. Low energy barriers can also provide a cost-effective solution even in areas where high energies events are expected. Results of full-scale tests are vital to any investigation on the behaviour of these structures. An experimental set-up has been developed at The University of Newcastle (AUS), to investigate the response of low energy rockfall barrier prototypes to low energy impacts. The Australian territory, and in particular New South Wales, is in fact characterised by rockfall events of low-to-medium intensity (50 kJ - 500 kJ) and the need of protection structures working within such energy range, is particularly felt [1]. The experiments involved the impact of a test block onto three spans, low energy barrier prototypes, made of steel structural posts, fully fixed at the base, side cables and a steel meshwork constituted by a double twist hexagonal wire net [2]. Test data enabled the development, calibration and assessment of FE models [3], on which non-linear and dynamic analyses have been performed addressing the effect of the block size. Results have shown that the response of the structure is strongly governed by the net. Data from tests conducted on the sole net and on the entire barrier showed in fact a similar trend, different to what typically observed for high capacity barriers, whose behaviour is also led by the presence of uphill cables and brakes. In particular, the numerical analyses have demonstrated a dependence of the net performance on the block size. In particular, a loss of capacity in the order of 50% occurred as the

  3. EPIDEMIOLOGICAL STUDY OF LOW ENERGY FRACTURES IN REPUBLIC OF ARMENIA

    Directory of Open Access Journals (Sweden)

    S. Saakyan

    2017-01-01

    Full Text Available Until present no data was available inArmeniain respect of incidence of low energy fractures that are typical of osteoporotic locations which consequently did not allow to evaluate the scope of this problem across the country.Purpose of the study – to identify the incidence of low energy fractures in proximal femur, in distal forearm, in proximal humerus and in distal tibia across population ofArmenia aged 50 years and older.Materials and methods. An observing population study was performed in two regions of Armenia during 2011-2013 where the frequency of selected locations in cases of moderate trauma was identified. During 2011-2012 the information was collected based on traumatology service records adding in 2013 other sources including primary level of healthcare due to observed infrequent applications for medical help in cases of trauma. Results. In 2013 the incidence of proximal femur fractures in men was reported as 136 cases per 100 000 of population aged 50 years and older, in women – 201 cases per 100 000. At the same time only 57.7% of patients with proximal femur fractures were admitted to hospital. Distal forearm fractures incidence in men and women was observed correspondingly 56/100 000 and 176/100 000 cases, proximal humerus fractures – 39/100 000 and 86/100 000 cases and distal tibia fractures – 39/100 000 and 86/100 000 cases. The predicted annual number of proximal femur fracture in Armenia amounts to 2067 cases, distal forearm fractures – 1205, proximal humerus fractures – 640.Conclusion. Epidemiological data that was collected for the first time on low energy fractures incidence confirmed the acute osteoporosis issue inArmenia and revealed the problems in organization of medical care for the group of senior patients with injuries.

  4. Low energy electron beam processing of YBCO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chromik, Š., E-mail: stefan.chromik@savba.sk [Institute of Electrical Engineering, SAS, Dúbravská cesta 9, 841 04 Bratislava (Slovakia); Camerlingo, C. [CNR-SPIN, Istituto Superconduttori, Materiali Innovativi e Dispositivi, via Campi Flegrei 34, 80078 Pozzuoli (Italy); Sojková, M.; Štrbík, V.; Talacko, M. [Institute of Electrical Engineering, SAS, Dúbravská cesta 9, 841 04 Bratislava (Slovakia); Malka, I.; Bar, I.; Bareli, G. [Department of Physics, Ben Gurion University of the Negev, P.O.B. 653, 84105 Beer Sheva (Israel); Jung, G. [Department of Physics, Ben Gurion University of the Negev, P.O.B. 653, 84105 Beer Sheva (Israel); Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland)

    2017-02-15

    Highlights: • Improvement of superconducting properties of irradiated bridges under certain conditions. • 30 keV irradiation influence CuO{sub 2} planes as well as oxygen chains. • Direct confirmation of changes in oxygen chains using micro-Raman spectroscopy. • Possibility of electron writing. - Abstract: Effects of low energy 30 keV electron irradiation of superconducting YBa{sub 2}Cu{sub 3}O{sub 7−δ} thin films have been investigated by means of transport and micro-Raman spectroscopy measurements. The critical temperature and the critical current of 200 nm thick films initially increase with increasing fluency of the electron irradiation, reach the maximum at fluency 3 − 4 × 10{sup 20} electrons/cm{sup 2}, and then decrease with further fluency increase. In much thinner films (75 nm), the critical temperature increases while the critical current decreases after low energy electron irradiation with fluencies below 10{sup 20} electrons/cm{sup 2}. The Raman investigations suggest that critical temperature increase in irradiated films is due to healing of broken Cu−O chains that results in increased carrier’s concentration in superconducting CuO{sub 2} planes. Changes in the critical current are controlled by changes in the density of oxygen vacancies acting as effective pinning centers for flux vortices. The effects of low energy electron irradiation of YBCO turned out to result from a subtle balance of many processes involving oxygen removal, both by thermal activation and kick-off processes, and ordering of chains environment by incident electrons.

  5. Low-energy electron scattering from molecules, biomolecules and surfaces

    CERN Document Server

    Carsky, Petr

    2011-01-01

    Since the turn of the 21st century, the field of electron molecule collisions has undergone a renaissance. The importance of such collisions in applications from radiation chemistry to astrochemistry has flowered, and their role in industrial processes such as plasma technology and lighting are vital to the advancement of next generation devices. Furthermore, the development of the scanning tunneling microscope highlights the role of such collisions in the condensed phase, in surface processing, and in the development of nanotechnology.Low-Energy Electron Scattering from Molecules, Biomolecule

  6. Validation of GPUMCD for low-energy brachytherapy seed dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hissoiny, Sami; Ozell, Benoit; Despres, Philippe; Carrier, Jean-Francois [Ecole polytechnique de Montreal, Departement de genie informatique et genie logiciel, 2500 chemin de Polytechnique, Montreal, QC, H3T 1J4 (Canada); Departement de radio-oncologie, Centre hospitalier universitaire de Quebec (CHUQ), 11 Cote du Palais, Quebec, QC, G1R 2J6 (Canada); Departement de physique, Universite de Montreal, Montreal, QC (Canada) and Departement de radio-oncologie and Centre de recherche du CHUM, Centre hospitalier de l' Universite de Montreal (CHUM), Montreal, QC, H2L 4M1 (Canada)

    2011-07-15

    Purpose: To validate GPUMCD, a new package for fast Monte Carlo dose calculations based on the GPU (graphics processing unit), as a tool for low-energy single seed brachytherapy dosimetry for specific seed models. As the currently accepted method of dose calculation in low-energy brachytherapy computations relies on severe approximations, a Monte Carlo based approach would result in more accurate dose calculations, taking in to consideration the patient anatomy as well as interseed attenuation. The first step is to evaluate the capability of GPUMCD to reproduce low-energy, single source, brachytherapy calculations which could ultimately result in fast and accurate, Monte Carlo based, brachytherapy dose calculations for routine planning. Methods: A mixed geometry engine was integrated to GPUMCD capable of handling parametric as well as voxelized geometries. In order to evaluate GPUMCD for brachytherapy calculations, several dosimetry parameters were computed and compared to values found in the literature. These parameters, defined by the AAPM Task-Group No. 43, are the radial dose function, the 2D anisotropy function, and the dose rate constant. These three parameters were computed for two different brachytherapy sources: the Amersham OncoSeed 6711 and the Imagyn IsoStar IS-12501. Results: GPUMCD was shown to yield dosimetric parameters similar to those found in the literature. It reproduces radial dose functions to within 1.25% for both sources in the 0.5< r <10 cm range. The 2D anisotropy function was found to be within 3% at r = 5 cm and within 4% at r = 1 cm. The dose rate constants obtained were within the range of other values reported in the literature.Conclusion: GPUMCD was shown to be able to reproduce various TG-43 parameters for two different low-energy brachytherapy sources found in the literature. The next step is to test GPUMCD as a fast clinical Monte Carlo brachytherapy dose calculations with multiple seeds and patient geometry, potentially providing

  7. Our clinical experience in low-energy laser medical treatments

    Science.gov (United States)

    Antipa, Ciprian; Bruckner, Ion I.; Crangulescu, Nicolae; Moldovan, Corneliu I.; Podoleanu, Adrian G.; Stanciulescu, Viorica; Ionescu, Elena

    1996-05-01

    In clinical research the efficiency of low-energy laser (LEL) therapy remains controversial. We present here some of the most important results of our clinical experience in this field. We summarize our opinions about the LEL effects in rheumatic diseases, in chronic pelvic inflammatory disorders, in the treatment of some dermatological disorders, and in the recovery of the distal forearm nerve from traumatic lesion after surgical suture. We conclude that these results may be important evidence for the real clinical efficiency of the LEL.

  8. Characterization of a free air ionization chamber for low energies

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Natalia F.; Xavier, Marcos; Vivolo, Vitor; Caldas, Linda V.E., E-mail: nsilva@ipen.br, E-mail: mxavier@ipen.br, E-mail: vivolo@ipen.br, E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Free air ionization chambers are used by most primary metrology laboratories as primary standards of the quantities air kerma and exposure in X-ray beams. The free air ionization chamber for low energies of the Calibration Laboratory (LCI) of IPEN showed in a characterization test a problem in the set responsible for the variation of its sensitive volume. After a modification in the support of the micrometers used for the movement of the internal cylinder and the establishment of a new alignment system protocol, the tests were redone. The objective of this work was to present the results obtained in the new condition. (author)

  9. Low energy electron beams for industrial and environmental applications

    CERN Document Server

    Skarda, Vlad

    2017-01-01

    EuCARD-2 Workshop, 8-9 December 2016, Warsaw, Poland. Organizers: Science and Technology Facilities Council, UK CERN - The European Organization for Nuclear Research, Switzerland, Institute of Nuclear Chemistry and Technology, Poland, Fraunhofer Institute for Electron Beam and Plasma Technology, Germany, Warsaw University of Technology, Poland. An article presents short information about EuCARD-2 Workshop “Low energy electron beams for industrial and environmental applications”, which was held in December 2016 in Warsaw. Objectives, main topics and expected output of meeting are described. List of organizers is included.

  10. Early forest fire detection using low-energy hydrogen sensors

    Directory of Open Access Journals (Sweden)

    K. Nörthemann

    2013-11-01

    Full Text Available Most huge forest fires start in partial combustion. In the beginning of a smouldering fire, emission of hydrogen in low concentration occurs. Therefore, hydrogen can be used to detect forest fires before open flames are visible and high temperatures are generated. We have developed a hydrogen sensor comprising of a metal/solid electrolyte/insulator/semiconductor (MEIS structure which allows an economical production. Due to the low energy consumption, an autarkic working unit in the forest was established. In this contribution, first experiments are shown demonstrating the possibility to detect forest fires at a very early stage using the hydrogen sensor.

  11. Low-energy house in Sisimiut - Data overview

    Energy Technology Data Exchange (ETDEWEB)

    Hvidthoeft Delff Andersen, P.; Rode, C.; Madsen, Henrik

    2013-08-15

    Experiments with persistently exciting heat inputs are a fundamental tool in identification of heat dynamics in buildings. The Low-energy house in Sisimiut, Greenland, provides an advanced experimental setup with frequent measurements of temperatures, heat inputs, and much more. This paper presents an overview of data collected since the installation of the new measurement and control system. Focus is on heat dynamics so only data related to that will be shown. 5 experiments have been conducted. They are described, and resulting data is shown. (Author)

  12. Characterization of low energy radioactive beams using direct reactions

    DEFF Research Database (Denmark)

    Johansen, J.G.; Fraser, M.A.; Bildstein, V.

    2013-01-01

    We demonstrate a new technique to determine the beam structure of low energy radioactive beams using coincidence events from a direct reaction. The technique will be described and tested using Geant4 simulations. We use the technique to determine for the first time the width, divergence and energy...... of an accelerated radioactive beam produced at ISOLDE. We use data from an experiment with an 11Be beam incident on a deuteron target producing 10Be from a (d,t) reaction. The T-REX Si detector array was used for particle detection, but the technique is applicable for other setups....

  13. Study on electron beam in a low energy plasma focus

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Muhammad Zubair, E-mail: mzubairkhan-um76@yahoo.com [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur, Malaysia and Department of Physics, Federal Urdu University of Arts, Science and Technology, 45320 Islamabad (Pakistan); Ling, Yap Seong; San, Wong Chiow [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-03-05

    Electron beam emission was investigated in a low energy plasma focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the electron beam. XR100CR X-ray spectrometer was used to explore the impact of the electron beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of electron beam is exceptionally notable with two different approaches using lead target inside hollow anode in our plasma focus device.

  14. Collisions between low-energy antihydrogen and atoms

    CERN Document Server

    Armour, E A G; Liu, Y; Martin, G D R

    2004-01-01

    Antihydrogen is currently the subject of great interest as cold H has recently been prepared at CERN by the ATHENA and ATRAP projects. This work is described elsewhere in this volume. In this paper, we describe a calculation that we have carried out recently for very low-energy HH scattering using the Kohn variational method and including three rearrangement channels in addition to the elastic channel. We also consider the He-H system and give a progress report on the calculation that we are currently carrying out for this system.

  15. Combining high-scale inflation with low-energy SUSY

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Stefan [Basel Univ. (Switzerland). Dept. of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg-Institut; Dutta, Koushik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Halter, Sebastian [Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg-Institut

    2011-12-15

    We propose a general scenario for moduli stabilization where low-energy supersymmetry can be accommodated with a high scale of inflation. The key ingredient is that the stabilization of the modulus field during and after inflation is not associated with a single, common scale, but relies on two different mechanisms. We illustrate this general scenario in a simple example, where during inflation the modulus is stabilized with a large mass by a Kaehler potential coupling to the field which provides the inflationary vacuum energy via its F-term. After inflation, the modulus is stabilized, for instance, by a KKLT superpotential. (orig.)

  16. Low-energy features of a 1-tev higgs sector

    CERN Document Server

    Appelquist, Thomas

    1979-01-01

    It seems very likely that the Higgs sector of a spontaneously broken gauge theory could be heavy (M = 1 TeV) and strongly interacting. By exploiting the intimate connection of such theories to nonlinear a models, it is possible to show under quite general conditions what sort of impact the heavy Higgs sector can have on low energy experiments (E << 1 TeV). In this talk, the techniques and results will be summar- ized for an SU(2) gauge theory, The analysis of the Weinberg-Salam and other realistic theories will appear in a forthcoming paper.

  17. Low-energy universality in three-body models

    CERN Document Server

    Delfino, A; Tomio, L

    2000-01-01

    We study the low-energy universality observed in three-body models through a scale-independent approach. From the already estimated infinite number of three-body excited energy states, which happen in the limit when the energy of the subsystem goes to zero, we are able to identify the lower energies of the helium trimers as possible examples of Thomas-Efimov states. By considering this example, we illustrate the usefulness of a scaling function, which we have defined. The approach is applied to bosonic systems of three identical particles, and also to the case where two kinds of particles are present. (author)

  18. Low-energy sputterings with the Monte Carlo Program ACAT

    Science.gov (United States)

    Yamamura, Y.; Mizuno, Y.

    1985-05-01

    The Monte Carlo program ACAT was developed to determine the total sputtering yields and angular distributions of sputtered atoms in physical processes. From computer results of the incident-energy dependent sputterings for various ion-target combinations the mass-ratio dependence and the bombarding-angle dependence of sputtering thresholds was obtained with the help of the Matsunami empirical formula for sputtering yields. The mass-ratio dependence of sputtering thresholds is in good agreement with recent theoretical results. The threshold energy of light-ion sputtering is a slightly increasing function of angle of incidence, while that of heavy-ion sputtering has a minimum value near theta = 60 deg. The angular distributions of sputtered atoms are also calculated for heavy ions, medium ions, and light ions, and reasonable agreements between calculated angular distributions and experimental results are obtained.

  19. Final report of the HFIR (High Flux Isotope Reactor) irradiation facilities improvement project

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, B.H.; Thoms, K.R.; West, C.D.

    1987-09-01

    The High-Flux Isotope Reactor (HFIR) has outstanding neutronics characteristics for materials irradiation, but some relatively minor aspects of its mechanical design severely limited its usefulness for that purpose. In particular, though the flux trap region in the center of the annular fuel elements has a very high neutron flux, it had no provision for instrumentation access to irradiation capsules. The irradiation positions in the beryllium reflector outside the fuel elements also have a high flux; however, although instrumented, they were too small and too few to replace the facilities of a materials testing reactor. To address these drawbacks, the HFIR Irradiation Facilities Improvement Project consisted of modifications to the reactor vessel cover, internal structures, and reflector. Two instrumented facilities were provided in the flux trap region, and the number of materials irradiation positions in the removable beryllium (RB) was increased from four to eight, each with almost twice the available experimental space of the previous ones. The instrumented target facilities were completed in August 1986, and the RB facilities were completed in June 1987.

  20. Advanced Multiphysics Thermal-Hydraulics Models for the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Prashant K [ORNL; Freels, James D [ORNL

    2015-01-01

    Engineering design studies to determine the feasibility of converting the High Flux Isotope Reactor (HFIR) from using highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel are ongoing at Oak Ridge National Laboratory (ORNL). This work is part of an effort sponsored by the US Department of Energy (DOE) Reactor Conversion Program. HFIR is a very high flux pressurized light-water-cooled and moderated flux-trap type research reactor. HFIR s current missions are to support neutron scattering experiments, isotope production, and materials irradiation, including neutron activation analysis. Advanced three-dimensional multiphysics models of HFIR fuel were developed in COMSOL software for safety basis (worst case) operating conditions. Several types of physics including multilayer heat conduction, conjugate heat transfer, turbulent flows (RANS model) and structural mechanics were combined and solved for HFIR s inner and outer fuel elements. Alternate design features of the new LEU fuel were evaluated using these multiphysics models. This work led to a new, preliminary reference LEU design that combines a permanent absorber in the lower unfueled region of all of the fuel plates, a burnable absorber in the inner element side plates, and a relocated and reshaped (but still radially contoured) fuel zone. Preliminary results of estimated thermal safety margins are presented. Fuel design studies and model enhancement continue.

  1. [Treatment of acute lithium intoxication with high-flux haemodialysis membranes].

    Science.gov (United States)

    Peces, R; Fernández, E J; Regidor, D; Peces, C; Sánchez, R; Montero, A; Selgas, R

    2006-01-01

    Lithium carbonate is commonly prescribed for the treatment of bipolar (manic-depressive) disorders. However, because of its narrow therapeutic index an excessive elevation of serum lithium concentration, either during chronic maintenance therapy or after an acute overdose, can result in serious toxicity. In addition to supportive care, the established treatment of severe lithium toxicity is haemodialysis. Conventional haemodialysis can reduce serum lithium rapidly, but post-dialysis rebound elevations with recurrent toxicity have been documented in old publications. High-flux membranes should be capable of removing more lithium per hour of haemodialysis, but published values are not available. We report here three patients with acute lithium intoxication who were treated successfully with bicarbonate and high-flux haemodialysis membranes. Our patients presented with a severe degree of intoxication, based on the amount of drug ingested, the initial serum lithium level, the severity of neurologic symptoms and systemic manifestations. Two patients developed acute renal failure probably as a result of volume depletion since it was rapidly reversible by haemodialysis and infusion therapy. In addition, consecutive haemodialysis sessions and improvement of renal function allowed a rapid decrease in serum lithium levels without haemodynamic instability or rebound elevations in lithium concentration. The effectiveness of the procedure in these cases can be attributed to the use of bicarbonate dialysate and high-efficiency dialysers. This is the first report describing the effect of high-efficiency dialysers on lithium pharmacokinetic. Using this technique the elimination rate of lithium was found to be greater than previously reported with haemodialysis.

  2. SPring-8 BL41XU, a high-flux macromolecular crystallography beamline

    Science.gov (United States)

    Hasegawa, Kazuya; Shimizu, Nobutaka; Okumura, Hideo; Mizuno, Nobuhiro; Baba, Seiki; Hirata, Kunio; Takeuchi, Tomoyuki; Yamazaki, Hiroshi; Senba, Yasunori; Ohashi, Haruhiko; Yamamoto, Masaki; Kumasaka, Takashi

    2013-01-01

    SPring-8 BL41XU is a high-flux macromolecular crystallography beamline using an in-vacuum undulator as a light source. The X-rays are monochromated by a liquid-nitrogen-cooling Si double-crystal monochromator, and focused by Kirkpatrick–Baez mirror optics. The focused beam size at the sample is 80 µm (H) × 22 µm (V) with a photon flux of 1.1 × 1013 photons s−1. A pinhole aperture is used to collimate the beam in the range 10–50 µm. This high-flux beam with variable size provides opportunities not only for micro-crystallography but also for data collection effectively making use of crystal volume. The beamline also provides high-energy X-rays covering 20.6–35.4 keV which allows ultra-high-resolution data to be obtained and anomalous diffraction using the K-edge of Xe and I. Upgrade of BL41XU for more rapid and accurate data collection is proceeding. Here, details of BL41XU are given and an outline of the upgrade project is documented. PMID:24121338

  3. Association of Beta-2 Microglobulin with Inflammation and Dislipidemia in High-Flux Membrane Hemodialysis Patients.

    Science.gov (United States)

    Topçiu-Shufta, Valdete; Miftari, Ramë; Haxhibeqiri, Valdete; Haxhibeqiri, Shpend

    2016-10-01

    Higher than expected cardiovascular mortality in hemodialysis patients, has been attributed to dyslipidemia as well as inflammation. Beta2-Microglobulin (β2M) is an independent predictor of outcome for hemodialysis patients and a representative substance of middle molecules. In 40 patients in high-flux membrane hemodialysis, we found negative correlation of β2M with high density lipoprotein (r=-0.73, p<0.001) and albumin (r= -0.53, p<0.001) and positive correlation with triglycerides (r=0.69, p<0.001), parathyroid hormone (r=0.58, p < 0.05) and phosphorus (r= 0.53, p<0.001). There was no correlation of β2M with C- reactive protein (CRP) and interleukin-6 (IL-6). During the follow-up period of three years, 6 out of 40 patients have died from cardiovascular events. In high-flux membrane hemodialysis patients, we observed a significant relationship of β2M with dyslipidemia and mineral bone disorders, but there was no correlation with inflammation.

  4. Direct synthesis of ultrathin SOI structure by extremely low-energy oxygen implantation

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp; Yachida, Gosuke; Inoue, Kodai; Toyohara, Taiga; Nakata, Jyoji [Department of mathematics and physics, Kanagawa University, 2946, Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2016-06-15

    We performed extremely low-energy {sup 16}O{sup +} implantation at 10 keV (R{sub p} ∼ 25 nm) followed by annealing aiming at directly synthesizing an ultrathin Si layer separated by a buried SiO{sub 2} layer in Si(001) substrates, and then investigated feasible condition of recrystallization and stabilization of the superficial Si and the buried oxide layer by significantly low temperature annealing. The elemental compositions were analyzed by Rutherford backscattering (RBS) and secondary ion mass spectroscopy (SIMS). The crystallinity of the superficial Si layer was quantitatively confirmed by ananlyzing RBS-channeling spectra. Cross-sectional morphologies and atomic configurations were observed by transmission electron microscope (TEM). As a result, we succeeded in directly synthesizing an ultrathin single-crystalline silicon layer with ≤20 nm thick separated by a thin buried stoichiometric SiO{sub 2} layer with ≤20 nm thick formed by extremely low-energy {sup 16}O{sup +} implantation followed by surprisingly low temperature annealing at 1050{sup ∘} C.

  5. Dynamic molecular structure retrieval from low-energy laser-induced electron diffraction spectra

    Science.gov (United States)

    Vu, Dinh-Duy T.; Phan, Ngoc-Loan T.; Hoang, Van-Hung; Le, Van-Hoang

    2017-12-01

    A recently developed quantitative rescattering theory showed that a laser-free elastic cross section can be separated from laser-induced electron diffraction (LIED) spectra. Based upon this idea, Blaga et al investigated the possibility of reconstructing molecular structure from LIED spectra (2012 Nature 483 7388). In the above study, an independent atoms model (IAM) was used to interpret high-energy electron–molecule collisions induced by a mid-infrared laser. Our research aims to extend the application range of this structural retrieval method to low-energy spectra induced by more common near-infrared laser sources. The IAM is insufficient in this case, so we switch to a more comprehensive model—the multiple scattering (MS) theory. From the original version concerning only neutral targets, we upgrade the model so that it is compatible with electron–ion collisions at low energy. With available LIED experiment data of CO2 and O2, the upgraded MS is shown to be greatly effective as a tool for molecular imaging from spectra induced by a near-infrared laser. The captured image is at about 2 fs after the ionization, shorter than the period 4–6 fs by using the mid-infrared laser in Blaga’s experiment.

  6. Semiconductor applications of plasma immersion ion implantation ...

    Indian Academy of Sciences (India)

    Many semiconductor integrated circuit manufacturing processes require high dose of implantation at very low energies. Conventional beam line ion implantation system suffers from low beam current at low energies, therefore, cannot be used economically for high dose applications. Plasma immersion ion implantation (PIII) ...

  7. Development of a low energy micro sheet forming machine

    Science.gov (United States)

    Razali, A. R.; Ann, C. T.; Shariff, H. M.; Kasim, N. I.; Musa, M. A.; Ahmad, A. F.

    2017-10-01

    It is expected that with the miniaturization of materials being processed, energy consumption is also being `miniaturized' proportionally. The focus of this study was to design a low energy micro-sheet-forming machine for thin sheet metal application and fabricate a low direct current powered micro-sheet-forming machine. A prototype of low energy system for a micro-sheet-forming machine which includes mechanical and electronic elements was developed. The machine was tested for its performance in terms of natural frequency, punching forces, punching speed and capability, energy consumption (single punch and frequency-time based). Based on the experiments, the machine can do 600 stroke per minute and the process is unaffected by the machine's natural frequency. It was also found that sub-Joule of power was required for a single stroke of punching/blanking process. Up to 100micron thick carbon steel shim was successfully tested and punched. It concludes that low power forming machine is feasible to be developed and be used to replace high powered machineries to form micro-products/parts.

  8. Low-energy housing estate 'SUNDAYS'

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, W.; Fink, C.; Thuer, A. [AEE - Arbeitsgemeinschaft Erneuerbare Energie, Gleisdorf (Austria)

    2000-07-01

    The low-energy housing estate 'SUNDAYS' was developed with the goal to find a prefabricated building standard with normal cost but very low energy demand. As a demonstration project in Gleisdorf / Styria six terraced houses and one office building were realised. The energy concept includes high insulation standard, passive solar gains by a conservatory and earth to air heat exchanger, active solar gains using thermal collectors and also biomass operating a pellets-boiler. A central waste air ventilator sucks the air out of the rooms and therefore fresh air comes into the conservatory directly or pre-warmed resp. pre-cooled through the earth to air heat exchanger. The remaining space-heating demand is covered by a low-temperature wall- and floor heating system. Results of the first measuring period in the office building showed a total energy demand covered by biomass and electricity of 35 kWh for each m{sup 2} of heated net floor space. (au)

  9. Development of Low Energy Gap and Fully Regioregular Polythienylenevinylene Derivative

    Directory of Open Access Journals (Sweden)

    Tanya M. S. David

    2014-01-01

    Full Text Available Low energy gap and fully regioregular conjugated polymers find its wide use in solar energy conversion applications. This paper will first briefly review this type of polymers and also report synthesis and characterization of a specific example new polymer, a low energy gap, fully regioregular, terminal functionalized, and processable conjugated polymer poly-(3-dodecyloxy-2,5-thienylene vinylene or PDDTV. The polymer exhibited an optical energy gap of 1.46 eV based on the UV-vis-NIR absorption spectrum. The electrochemically measured highest occupied molecular orbital (HOMO level is −4.79 eV, resulting in the lowest unoccupied molecular orbital (LUMO level of −3.33 eV based on optical energy gap. The polymer was synthesized via Horner-Emmons condensation and is fairly soluble in common organic solvents such as tetrahydrofuran and chloroform with gentle heating. DSC showed two endothermic peaks at 67°C and 227°C that can be attributed to transitions between crystalline and liquid states. The polymer is thermally stable up to about 300°C. This polymer appears very promising for cost-effective solar cell applications.

  10. Low energy probes of PeV scale sfermions

    Energy Technology Data Exchange (ETDEWEB)

    Altmannshofer, Wolfgang; Harnik, Roni; Zupan, Jure

    2013-11-27

    We derive bounds on squark and slepton masses in mini-split supersymmetry scenario using low energy experiments. In this setup gauginos are at the TeV scale, while sfermions are heavier by a loop factor. We cover the most sensitive low energy probes including electric dipole moments (EDMs), meson oscillations and charged lepton flavor violation (LFV) transitions. A leading log resummation of the large logs of gluino to sfermion mass ratio is performed. A sensitivity to PeV squark masses is obtained at present from kaon mixing measurements. A number of observables, including neutron EDMs, mu->e transitions and charmed meson mixing, will start probing sfermion masses in the 100 TeV-1000 TeV range with the projected improvements in the experimental sensitivities. We also discuss the implications of our results for a variety of models that address the flavor hierarchy of quarks and leptons. We find that EDM searches will be a robust probe of models in which fermion masses are generated radiatively, while LFV searches remain sensitive to simple-texture based flavor models.

  11. The high-flux effect on deuterium retention in TiC and TaC doped tungsten at high temperatures

    Science.gov (United States)

    Zibrov, Mikhail; Bystrov, Kirill; Mayer, Matej; Morgan, Thomas W.; Kurishita, Hiroaki

    2017-10-01

    Samples made of tungsten (W) doped either with titanium carbide (W-1.1TiC) or tantalum carbide (W-3.3TaC) were exposed to a low-energy (40 eV/D), high-flux (1.8-5 × 1023 D/m2s) deuterium (D) plasma at temperatures of about800 K, 1050 K, and 1250 K to a fluence of about1 × 1027 D/m2. The deuterium (D) inventory in the samples was examined by nuclear reaction analysis and thermal desorption spectroscopy. At 800 K the D bulk concentrations and total D inventories in W-1.1TiC and W-3.3TaC were more than one order of magnitude higher compared to that in pure polycrystalline W. At 1050 K and 1250 K the D concentrations in all types of samples were very low (≤10-5 at. fr.); however the D inventories in W-1.1TiC were significantly higher compared to those in W-3.3TaC and pure W. It is suggested that D trapping inside the carbide precipitates and at their boundaries is essential at high temperatures and high incident fluxes, especially in W-1.1TiC.

  12. Ion-beam technologies

    Energy Technology Data Exchange (ETDEWEB)

    Fenske, G.R. [Argonne National Lab., IL (United States)

    1993-01-01

    This compilation of figures and diagrams reviews processes for depositing diamond/diamond-like carbon films. Processes addressed are chemical vapor deposition (HFCVD, PACVD, etc.), plasma vapor deposition (plasma sputtering, ion beam sputtering, evaporation, etc.), low-energy ion implantation, and hybrid processes (biased sputtering, IBAD, biased HFCVD, etc.). The tribological performance of coatings produced by different means is discussed.

  13. A low energy accumulation stage for a beta-beam facility

    CERN Document Server

    Källberg, Anders; Lindroos, Mats

    2006-01-01

    The EU supported EURISOL Design Study encompasses a beta-beam facility for neutrino physics. Intense electron (anti-)neutrino beams are in such a machine generated through the decay of radioactive ions in a high energy storage ring. The two main candidate isotopes for the generation of a neutrino and an antineutrino beam are 6He and 18Ne. The intensities required are hard to reach, in particular for the neon case. A possible solution to increase the intensity is to use an accumulator ring with an electron cooler. Critical parameters such as cooling times and current limitations due to space charge and tune shifts are presently being optimized. We will in this presentation give an overview of the low energy accumulation stage and review recent work on this option.

  14. Mimicking bipolar sextupole power supplies for low-energy operations at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Montag, C.; Bruno, D.; Jain, A.; Robert-Demolaize, G.; Satogata, T.; Tepikian, S.

    2011-03-28

    RHIC operated at energies below the nominal ion injection energy of E=9.8 GeV/u in 2010. Earlier test runs and magnet measurements indicated that all defocusing sextupole unipolar power supplies should be reversed to provide the proper sign of chromaticity. However, vertical chromaticity at E=3.85 GeV/u with this power supply configuration was still not optimal. This uncertainty inspired a new machine configuration where only half of the defocusing sextupole power supplies were reversed, taking advantage of the flexibility of the RHIC nonlinear chromaticity correction system to mimic bipolar sextupoles. This configuration resulted in a 30 percent luminosity gain and eliminated the need for further polarity changes for later 2010 low energy physics operations. Here we describe the background to this problem, operational experience, and RHIC online model changes to implement this solution.

  15. Low-energy electron diffraction experiment, theory and surface structure determination

    CERN Document Server

    Hove, Michel A; Chan, Chi-Ming

    1986-01-01

    Surface crystallography plays the same fundamental role in surface science which bulk crystallography has played so successfully in solid-state physics and chemistry. The atomic-scale structure is one of the most important aspects in the understanding of the behavior of surfaces in such widely diverse fields as heterogeneous catalysis, microelectronics, adhesion, lubrication, cor­ rosion, coatings, and solid-solid and solid-liquid interfaces. Low-Energy Electron Diffraction or LEED has become the prime tech­ nique used to determine atomic locations at surfaces. On one hand, LEED has yielded the most numerous and complete structural results to date (almost 200 structures), while on the other, LEED has been regarded as the "technique to beat" by a variety of other surface crystallographic methods, such as photoemission, SEXAFS, ion scattering and atomic diffraction. Although these other approaches have had impressive successes, LEED has remained the most productive technique and has shown the most versatility...

  16. Nanoscale patterning of complex magnetic nanostructures by reduction with low-energy protons.

    Science.gov (United States)

    Kim, Sanghoon; Lee, Soogil; Ko, Jungho; Son, Jangyup; Kim, Minseok; Kang, Shinill; Hong, Jongill

    2012-09-01

    Techniques that can produce patterns with nanoscale details on surfaces have a central role in the development of new electronic, optical and magnetic devices and systems. High-energy ion irradiation can produce nanoscale patterns on ferromagnetic films by destroying the structure of layers or interfaces, but this approach can damage the film and introduce unwanted defects. Moreover, ferromagnetic nanostructures that have been patterned by ion irradiation often interfere with unpatterned regions through exchange interactions, which results in a loss of control over magnetization switching. Here, we demonstrate that low-energy proton irradiation can pattern an array of 100-nm-wide single ferromagnetic domains by reducing [Co(3)O(4)/Pd](10) (a paramagnetic oxide) to produce [Co/Pd](10) (a ferromagnetic metal). Moreover, there are no exchange interactions in the final superlattice, and the ions have a minimal impact on the overall structure, so the interfaces between alternate layers of cobalt (which are 0.6 nm thick) and palladium (1.0 nm) remain intact. This allows the reduced [Co/Pd](10) superlattice to produce a perpendicular magnetic anisotropy that is stronger than that observed in the metallic [Co/Pd](10) superlattices we prepared for reference. We also demonstrate that our non-destructive approach can reduce CoFe(2)O(4) to metallic CoFe.

  17. Nonlinear and long-term beam dynamics in low energy storage rings

    Directory of Open Access Journals (Sweden)

    A. I. Papash

    2013-06-01

    Full Text Available Electrostatic storage rings operate at very low energies in the keV range and have proven to be invaluable tools for atomic and molecular physics. Because of the mass independence of electric rigidity, these machines are able to store a wide range of different particles, from light ions to heavy singly charged biomolecules, opening up unique research opportunities. However, earlier measurements have shown strong limitations in maximum beam intensity, fast decay of the stored ion current, and reduced beam lifetime. The nature of these effects has not been fully understood and an improved understanding of the physical processes influencing beam motion and stability in such rings is needed. In this paper, a comprehensive study into nonlinear and long-term beam dynamics studies is presented on the examples of a number of existing and planned electrostatic storage rings using the BETACOOL, OPERA-3D, and MAD-X simulation software. A detailed investigation into ion kinetics, under consideration of effects from electron cooling and multiple scattering of the beam on a supersonic gas jet target, is carried out and yields a consistent explanation of the physical effects in a whole class of storage rings. The lifetime, equilibrium momentum spread, and equilibrium lateral spread during collisions with the target are estimated. In addition, the results from experiments at the Test Storage Ring, where a low-intensity beam of CF^{+} ions at 93  keV/u has been shrunk to extremely small dimensions, are reproduced. Based on these simulations, the conditions for stable ring operation with an extremely low-emittance beam are presented. Finally, results from studies into the interaction of 3–30 keV ions with a gas jet target are summarized.

  18. White paper on nuclear astrophysics and low-energy nuclear physics, Part 2: Low-energy nuclear physics

    Science.gov (United States)

    Carlson, Joe; Carpenter, Michael P.; Casten, Richard; Elster, Charlotte; Fallon, Paul; Gade, Alexandra; Gross, Carl; Hagen, Gaute; Hayes, Anna C.; Higinbotham, Douglas W.; Howell, Calvin R.; Horowitz, Charles J.; Jones, Kate L.; Kondev, Filip G.; Lapi, Suzanne; Macchiavelli, Augusto; McCutchen, Elizabeth A.; Natowitz, Joe; Nazarewicz, Witold; Papenbrock, Thomas; Reddy, Sanjay; Riley, Mark A.; Savage, Martin J.; Savard, Guy; Sherrill, Bradley M.; Sobotka, Lee G.; Stoyer, Mark A.; Betty Tsang, M.; Vetter, Kai; Wiedenhoever, Ingo; Wuosmaa, Alan H.; Yennello, Sherry

    2017-05-01

    Over the last decade, the Low-Energy Nuclear Physics (LENP) and Nuclear Astrophysics (NAP) communities have increasingly organized themselves in order to take a coherent approach to resolving the challenges they face. As a result, there is a high level of optimism in view of the unprecedented opportunities for substantial progress. In preparation of the 2015 US Nuclear Science Long Range Plan (LRP), the two American Physical Society Division of Nuclear Physics town meetings on LENP and NAP were held jointly on August 21-23, 2014, at Texas A&M, College Station, in Texas. These meetings were co-organized to take advantage of the strong synergy between the two fields. The present White Paper attempts to communicate the sense of great anticipation and enthusiasm that came out of these meetings. A unanimously endorsed set of joint resolutions condensed from the individual recommendations of the two town meetings were agreed upon. The present LENP White Paper discusses the above and summarizes in detail for each of the sub-fields within low-energy nuclear physics, the major accomplishments since the last LRP, the compelling near-term and long-term scientific opportunities plus the resources needed to achieve these goals, along with the scientific impact on, and interdisciplinary connections to, other fields.

  19. Low-energy and very-low energy total cross sections for electron collisions with N2

    Science.gov (United States)

    Kitajima, Masashi; Kishino, Takaya; Okumura, Takuma; Kobayashi, Naomasa; Sayama, Atsushi; Mori, Yuma; Hosaka, Kouichi; Odagiri, Takeshi; Hoshino, Masamitsu; Tanaka, Hiroshi

    2017-06-01

    Absolute grand total cross sections for electron scattering from N2 are obtained in the energy range from 20 eV down to 5 meV with very narrow electron energy width of 9 meV using the threshold-photoelectron source. Total cross sections obtained in the present study are compared with the previous experimentally obtained results. At the very-low energy region below 50 meV, the present total cross sections are somewhat smaller than those reported by the Aarhus group [S.V. Hoffmann et al., Rev. Sci. Instrum. 73, 4157 (2002)], which has been the only experimental work that provided the total cross sections in the very-low energy region. The energy positions of the peaks in the total cross sections due to the 2Πg shape resonance are obtained with higher accuracy, due to the improved uncertainty of the energy position in the present measurement compared to the previous works. The resonance structure in the total cross sections due to the Feshbach resonances of N2 at around 11.5 eV are also observed. Analysis of the resonant structure was carried out in order to determine the values of resonance width of Feshbach resonances of N2. Contribution to the Topical Issue: "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

  20. Before the Ring: synthesis of linear organic molecules in astrophysical ices by low energy electron impact

    Science.gov (United States)

    Huels, Michael A.; Bass Andrew, D.; Mirsaleh-Kohan, Nasrin; Sanche, Leon

    The question of the origin for the building blocks of life, either synthesized here on earth, or in space [1], has been the subject of much debate, experimental investigation, or astronomical observation, much of it stimulated by the early experiments of Miller [2], and subsequent space radiation related variations thereof [3-5]. And while the precise details of the formation of even the simplest biomolecules that make up life on earth still remain shrouded inmystery, one of the notions that persist throughout the debate is that the building blocks of life, such as amino-acids, or even the cyclic components of RNA and DNA, or other cyclic hydrocarbons (e.g. PHAs), where synthesized via radiolysis [6] either in the earths proto-atmosphere, its early oceans, or in the near interstellar space surrounding the early earth. Here we provide experimental evidence for the hypothesis that interactions of low energy secondary electrons and ions, formed during the radiolysis of matter, with atoms and molecules in the medium, may have played, and may still play an important role in the chemical transformation of astrophysical or planetary surface ices [7], where they lead to the synthesis of more complex chemical species from less complex, naturally occurring components. We report the synthesis and desorption of new chemical species from simple molecular surface ices, containing CH4 / CD4 , C2 D2 , O2 , CO, CO2 , or N2 in various combination mixtures, irradiated by low energy (life's most basic cyclic molecular components in planetary, or astrophysical surface ices that are continuously subjected to the types of space radiations (UV, X-or -ray, or heavy ions) that can generate such low energy secondary electrons. [Funded by NSERC and Canadian Space Agency] [1] P. Ehrenfreund, S. Rasmussen, J. Cleaves, L. Chen, Astrobiology 6 (2006) 490. [2] (a) S.L. Miller, Science 117 (1953) 528; (b) S.L. Miller, J. Am. Chem. Soc. 77 (1955) 2351. [3] (a) M.H. Morre, R.L. Hudson, Icarus 140

  1. Structural biology facilities at Brookhaven National Laboratory`s high flux beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korszun, Z.R.; Saxena, A.M.; Schneider, D.K. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    The techniques for determining the structure of biological molecules and larger biological assemblies depend on the extent of order in the particular system. At the High Flux Beam Reactor at the Brookhaven National Laboratory, the Biology Department operates three beam lines dedicated to biological structure studies. These beam lines span the resolution range from approximately 700{Angstrom} to approximately 1.5{Angstrom} and are designed to perform structural studies on a wide range of biological systems. Beam line H3A is dedicated to single crystal diffraction studies of macromolecules, while beam line H3B is designed to study diffraction from partially ordered systems such as biological membranes. Beam line H9B is located on the cold source and is designed for small angle scattering experiments on oligomeric biological systems.

  2. Development of a Scale Model for High Flux Isotope Reactor Cycle 400

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Dan [ORNL

    2012-03-01

    The development of a comprehensive SCALE computational model for the High Flux Isotope Reactor (HFIR) is documented and discussed in this report. The SCALE model has equivalent features and functionality as the reference MCNP model for Cycle 400 that has been used extensively for HFIR safety analyses and for HFIR experiment design and analyses. Numerical comparisons of the SCALE and MCNP models for the multiplication constant, power density distribution in the fuel, and neutron fluxes at several locations in HFIR indicate excellent agreement between the results predicted with the two models. The SCALE HFIR model is presented in sufficient detail to provide the users of the model with a tool that can be easily customized for various safety analysis or experiment design requirements.

  3. Model for luminescent response of scintillation detectors at low energies; Modelo para la respuesta luminiscente de detectores de centelleo a bajas energias

    Energy Technology Data Exchange (ETDEWEB)

    Cruz G, H.S.; Michaelian P, K.; Menchaca R, A.; Martinez D, A.; Belmont M, E. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    In this work it was used the induced luminescence by incident energetic ions model over a material proposed by K. Michaelian and A. Menchaca (1) which was changed the classic impact parameter for one quantum so seeing whether this one improve or not the model to experimental data at low energies. (Author)

  4. Modeling energy flexibility of low energy buildings utilizing thermal mass

    DEFF Research Database (Denmark)

    Foteinaki, Kyriaki; Heller, Alfred; Rode, Carsten

    2016-01-01

    In the future energy system a considerable increase in the penetration of renewable energy is expected, challenging the stability of the system, as both production and consumption will have fluctuating patterns. Hence, the concept of energy flexibility will be necessary in order for the consumption...... to match the production patterns, shifting demand from on-peak hours to off-peak hours. Buildings could act as flexibility suppliers to the energy system, through load shifting potential, provided that the large thermal mass of the building stock could be utilized for energy storage. In the present study...... the load shifting potential of an apartment of a low energy building in Copenhagen is assessed, utilizing the heat storage capacity of the thermal mass when the heating system is switched off for relieving the energy system. It is shown that when using a 4-hour preheating period before switching off...

  5. NRV web knowledge base on low-energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Karpov, V., E-mail: karpov@jinr.ru; Denikin, A. S. [Joint Institute for Nuclear Research (Russian Federation); Alekseev, A. P. [Chuvash State University (Russian Federation); Zagrebaev, V. I.; Rachkov, V. A.; Naumenko, M. A.; Saiko, V. V. [Joint Institute for Nuclear Research (Russian Federation)

    2016-09-15

    Principles underlying the organization and operation of the NRV web knowledge base on low-energy nuclear physics (http://nrv.jinr.ru) are described. This base includes a vast body of digitized experimental data on the properties of nuclei and on cross sections for nuclear reactions that is combined with a wide set of interconnected computer programs for simulating complex nuclear dynamics, which work directly in the browser of a remote user. Also, the current situation in the realms of application of network information technologies in nuclear physics is surveyed. The potential of the NRV knowledge base is illustrated in detail by applying it to the example of an analysis of the fusion of nuclei that is followed by the decay of the excited compound nucleus formed.

  6. Search for low Energy solar Axions with CAST

    CERN Document Server

    Cantatore, Giovanni; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B.; Borghi, S.; Boydag, F.S.; Brauninger, H.; Cantatore, G.; Carmona, J.M.; Cebrian, S.; Cetin, S.A.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Dogan, O.B.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Fischer, H.; Franz, J.; Galan, J.; Gazis, E.; Geralis, T.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hasinoff, M.; Heinsius, F.H.; Hikmet, I.; Hoffmann, D.H.H.; Irastorza, I.G.; Jacoby, J.; Jakovcic, K.; Kang, D.; Karageorgopoulou, T.; Karuza, M.; Konigsmann, Kay; Kotthaus, R.; Krcmar, M.; Kousouris, K.; Kuster, M.; Lakic, B.; Lasseur, C.; Liolios, A.; Ljubicic, A.; Lozza, V.; Lutz, G.; Luzon, G.; Miller, D.; Morales, A.; Morales, J.; Niinikoski, T.; Nordt, A.; Ortiz, A.; Papaevangelou, T.; Pivovaroff, M.; Placci, A.; Raiteri, G.; Raffelt, G.; Riege, H.; Rodriguez, A.; Ruz, J.; Savvidis, I.; Semertzidis, Y.; Serpico, P.; Solanki, S.K.; Soufli, R.; Stewart, L.; Tsagri, M.; van Bibber, K.; Villar, J.; Vogel, J.; Walckiers, L.; Zioutas, K.

    2008-01-01

    We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.

  7. District Heating in Areas with Low Energy Houses

    DEFF Research Database (Denmark)

    Tol, Hakan Ibrahim

    in Denmark. The second case study was aimed at solving another regional energy planning scheme, one concerned with already existing houses, the heat requirements of which were currently being met by use of a natural gas grid or a conventional high-temperature district heating network. The idea considered......-energy houses involved, together with the idea of utilizing booster pumps in the district heating network and (ii) use of network layouts of either a branched (tree-like) or a looped type. The methods developed were applied in a case study, the data of which was provided by the municipality of Roskilde...... houses there being considered for renovation to houses of a low-energy class, and due to the existing heat-supply energy infrastructure there being a natural gas grid. The third case study carried out aimed at developing energy conversion systems based on use of renewable energy sources that were...

  8. Opportunistic Sensor Data Collection with Bluetooth Low Energy

    Directory of Open Access Journals (Sweden)

    Sergio Aguilar

    2017-01-01

    Full Text Available Bluetooth Low Energy (BLE has gained very high momentum, as witnessed by its widespread presence in smartphones, wearables and other consumer electronics devices. This fact can be leveraged to carry out opportunistic sensor data collection (OSDC in scenarios where a sensor node cannot communicate with infrastructure nodes. In such cases, a mobile entity (e.g., a pedestrian or a vehicle equipped with a BLE-enabled device can collect the data obtained by the sensor node when both are within direct communication range. In this paper, we characterize, both analytically and experimentally, the performance and trade-offs of BLE as a technology for OSDC, for the two main identified approaches, and considering the impact of its most crucial configuration parameters. Results show that a BLE sensor node running on a coin cell battery can achieve a lifetime beyond one year while transferring around 10 Mbit/day, in realistic OSDC scenarios.

  9. The Construction of Affordable Low Energy Prefabricated Housing in Denmark

    DEFF Research Database (Denmark)

    Vibæk, Kasper Sánchez; Beim, Anne

    2013-01-01

    . Consideration of all these factors is a precondition for a truly integrated practice and as this chapter demonstrates, innovative project delivery methods founded on the manufacturing of prefabricated buildings contribute to the production of high performance homes that are cost effective to construct, energy......Can prefabrication contribute to the development of high performance homes? To answer this question, this chapter defines high performance in more broadly inclusive terms, acknowledging the technical, architectural, social and economic conditions under which energy consumption and production occur...... efficient to operate and valuable for building communities. Herein discussed are two successful examples of low energy prefabricated housing projects built in Copenhagen Denmark, which embraced both the constraints and possibilities offered by prefabrication....

  10. Improved global alpha-optical model potentials at low energies

    CERN Document Server

    Demetriou, P; Goriely, S

    2002-01-01

    Many nuclear astrophysics applications involve radiative alpha-particle captures, alpha decays and alpha-particle transfer reactions. Theoretical estimates of the corresponding reaction rates within the framework of the statistical model of Hauser-Feshbach remain highly uncertain due to the poor knowledge of the alpha-nucleus optical model potential, especially at low energies far below the Coulomb barrier. In the present paper we propose a new global alpha-optical potential that takes into account the strong energy dependence and nuclear structure effects that characterize the alpha-nucleus interaction. The real part of the potential is calculated using a double-folding procedure over the M3Y effective nucleon-nucleon interaction. A Woods-Saxon potential is used for the imaginary potential where now a new parameterization is introduced to describe its energy dependence. The influence of purely volume absorption or volume plus surface absorption on the description of the experimental data is investigated. Fin...

  11. Sustainable Heating/Cooling for Low Energy Buildings

    DEFF Research Database (Denmark)

    Krajčík, M.; Olesen, Bjarne W.; Petráš, D.

    2012-01-01

    with high accuracy and under well defined boundary conditions, which can be further verified by field measurements or used for validation of a computer simulation. A set of experimental studies of air distribution, ventilation effectiveness and thermal environment were carried out in a simulated room heated....../cooled and ventilated by different concepts, at various boundary conditions, differing in supply air temperature, floor temperature, simulated heat gain/heat loss, nominal air change rate and positions of air terminal devices. The experimental room simulated corresponds to a residential room or a single office room...... located in a low-energy building. Procedures and indicators that can be successfully used for experimental investigations of indoor environment are described and a sample of measured data is reported....

  12. Contact angle patterns on low-energy surfaces.

    Science.gov (United States)

    David, Robert; Neumann, A Wilhelm

    2014-04-01

    It is well-known that on a given low-energy solid surface, the contact angles of different organic liquids follow a regular pattern. The experimental evidence for this, and semi-empirical equations describing the pattern, are reviewed. Theoretical and computational efforts to explain the pattern are discussed, and a simplified analytical approach is presented. The main pattern of contact angles is seen to arise from two factors: a common combining rule for liquid-solid molecular interactions, and the reduced density of liquid molecules adjacent to a lower-energy solid surface. Irregular departures from the main pattern are due to chemical effects originating in molecular structure. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Five low energy phosphorene allotropes constructed through gene segments recombination

    Science.gov (United States)

    He, Chaoyu; Zhang, Chunxiao; Tang, Chao; Ouyang, Tao; Li, Jin; Zhong, Jianxin

    2017-04-01

    Based on the crystal structures of the previously proposed low energy η-P and θ-P, five new phosphorene allotropes were predicted through gene segments recombination method. These five new phosphorene allotropes are confirmed dynamically stable and energetically more favorable than their parents (η-P and θ-P). Especially, the XX-XX type G1-P is confirmed energetically more favorable than most of all the previously proposed phosphorene allotropes, including black phosphorene and blue phosphorene, which is highly expected to be synthesized in future experiment through vapor deposition or epitaxial growth method like blue β-P. The calculated results also show that such a new promising phosphorene allotrope G1-P is a potential candidate for application in nano-electronics according to its middle band gap of about 1.491 eV from DFT-HSE06 calculation.

  14. Comparison of different windows for low-energy houses

    Directory of Open Access Journals (Sweden)

    Juras Peter

    2017-01-01

    Full Text Available This paper deals with an outcome of long-term experimental measurement of windows suitable for low-energy or zero houses. Three different windows are evaluated since 2011 in the Laboratory of the Department of Building Engineering and Urban Planning, Faculty of Civil Engineering, University of Zilina. All windows have implemented triple glazing, but with various frame type. Two frames are made from plastic and one from wood. The plastic frames differ from each other with use of thermal insulation inside one of mentioned frames. The test room has adjustable indoor boundary conditions and is exposed to real outdoor climate conditions measured through the own detached experimental weather station. Temperatures and heat fluxes are continuously measured on glazings and frames. This paper compares the windows by the requirements of Slovak standard on the inner surface temperatures and differences of the thermal transmittance for glazing and sash.

  15. Heavy neutrino threshold effects in low energy phenomenology

    CERN Document Server

    Leontaris, George K; Ross, Graham G

    1995-01-01

    Right handed neutrinos with mass of {\\cal O} \\; (10^{12}-10^{13}) GeV are required to implement the see-saw mechanism and generate neutrino masses capable of playing a role in structure formation. Moreover models of fermion masses often relate the Yukawa couplings involving these neutrinos to the up-quark Yukawa couplings. Here we study the effects of such couplings on the radiative corrections to quark masses. We find that b-\\tau equality at M_{GUT} may still give the correct m_b/m_{\\tau}-- ratio at low energies, but only if there is large \\mu-\\tau mixing in the charged leptonic sector. We propose specific mass matrix ``textures'' dictated by a U(1) family symmetry whose structure preserves m_b=m_{\\tau} at M_{GUT}. In these schemes, due to the large \

  16. NRV web knowledge base on low-energy nuclear physics

    Science.gov (United States)

    Karpov, A. V.; Denikin, A. S.; Naumenko, M. A.; Alekseev, A. P.; Rachkov, V. A.; Samarin, V. V.; Saiko, V. V.; Zagrebaev, V. I.

    2017-07-01

    The paper describes the principles of organization and operation of the NRV web knowledge base on low-energy nuclear physics (http://nrv.jinr.ru/) which integrates a large amount of digitized experimental data on the properties of nuclei and nuclear reaction cross sections with a wide range of computational programs for modeling of nuclear properties and various processes of nuclear dynamics which work directly in the browser of a remote user. The paper also gives an overview of the current situation in the field of application of network information technologies in nuclear physics. The features of the NRV knowledge base are illustrated in detail on the example of the analysis of nucleon transfer reactions within the distorted wave Born approximation.

  17. Modeling of human movement monitoring using Bluetooth Low Energy technology.

    Science.gov (United States)

    Mokhtari, G; Zhang, Q; Karunanithi, M

    2015-01-01

    Bluetooth Low Energy (BLE) is a wireless communication technology which can be used to monitor human movements. In this monitoring system, a BLE signal scanner scans signal strength of BLE tags carried by people, to thus infer human movement patterns within its monitoring zone. However to the extent of our knowledge one main aspect of this monitoring system which has not yet been thoroughly investigated in literature is how to build a sound theoretical model, based on tunable BLE communication parameters such as scanning time interval and advertising time interval, to enable the study and design of effective and efficient movement monitoring systems. In this paper, we proposed and developed a statistical model based on Monte-Carlo simulation, which can be utilized to assess impacts of BLE technology parameters in terms of latency and efficiency, on a movement monitoring system, and can thus benefit a more efficient system design.

  18. Bluetooth low energy: wireless connectivity for medical monitoring.

    Science.gov (United States)

    Omre, Alf Helge

    2010-03-01

    Electronic wireless sensors could cut medical costs by enabling physicians to remotely monitor vital signs such as blood pressure, blood glucose, and blood oxygenation while patients remain at home. According to the IDC report "Worldwide Bluetooth Semiconductor 2008-2012 Forecast," published November 2008, a forthcoming radio frequency communication ("wireless connectivity") standard, Bluetooth low energy, will link wireless sensors via radio signals to the 70% of cell phones and computers likely to be fitted with the next generation of Bluetooth wireless technology, leveraging a ready-built infrastructure for data transmission. Analysis of trends indicated by this data can help physicians better manage diseases such as diabetes. The technology also addresses the concerns of cost, compatibility, and interoperability that have previously stalled widespread adoption of wireless technology in medical applications. (c) 2010 Diabetes Technology Society.

  19. Opportunistic Sensor Data Collection with Bluetooth Low Energy.

    Science.gov (United States)

    Aguilar, Sergio; Vidal, Rafael; Gomez, Carles

    2017-01-23

    Bluetooth Low Energy (BLE) has gained very high momentum, as witnessed by its widespread presence in smartphones, wearables and other consumer electronics devices. This fact can be leveraged to carry out opportunistic sensor data collection (OSDC) in scenarios where a sensor node cannot communicate with infrastructure nodes. In such cases, a mobile entity (e.g., a pedestrian or a vehicle) equipped with a BLE-enabled device can collect the data obtained by the sensor node when both are within direct communication range. In this paper, we characterize, both analytically and experimentally, the performance and trade-offs of BLE as a technology for OSDC, for the two main identified approaches, and considering the impact of its most crucial configuration parameters. Results show that a BLE sensor node running on a coin cell battery can achieve a lifetime beyond one year while transferring around 10 Mbit/day, in realistic OSDC scenarios.

  20. Low-energy structure of four-dimensional superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Zwirner, F.

    1988-05-01

    The N = 1, d = 4 supergravity theories derived as the low-energy limit of four-dimensional superstrings are discussed, focusing on the properties of their effective potentials. Gauge symmetry breaking is possible along several flat directions. A class of superpotential modifications is introduced, which describes supersymmetry breaking with vanishing cosmological constant and Str M{sup 2} = 0 at any minimum of the tree level potential. Under more restrictive assumptions, there are minima with broken supersymmetry at which also Str f(M{sup 2}) = 0 for any function f, so that the whole one-loop cosmological constant vanishes. This result is interpreted in terms of a new discrete boson-fermion symmetry, relating particles whose helicities differ by 3/2, e.g., the graviton and the dilatino.' 21 refs.

  1. Formation of tetradecane nanoemulsion by low-energy emulsification methods

    Energy Technology Data Exchange (ETDEWEB)

    Schalbart, P. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto M5S 3E5 (Canada); Kawaji, M. [Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto M5S 3E5 (Canada); Department of Mechanical Engineering, City College of New York, New York, NY 10032 (United States); Fumoto, K. [Graduate School of Science and Technology, Hirosaki University, Bunkyo-cho, Hirosaki 036-8561 (Japan)

    2010-12-15

    Compared with conventional single-phase heat transfer fluids such as chilled water for air conditioning applications, the apparent specific heat of phase change emulsions in the phase change temperature range is greatly increased, thus offering attractive opportunities for heat transfer enhancement as well as thermal energy transportation and storage. Milky white oil-in-water (O/W) emulsions have been formed in the system water/Tween60 + Span60/tetradecane by using several emulsification routes among the low-energy emulsification methods (e.g., phase inversion temperature method). The best emulsification routes for good stability of the resulting emulsions have been determined. Thermal analyses indicated promising properties of phase change nanoemulsions for thermal storage and transport applications. (author)

  2. Low Energy Reaction cell for advanced space power applications

    Science.gov (United States)

    Miley, George H.; Rice, Eric

    2001-02-01

    Power units using Low Energy Reactions (LENRs) are under study as a radical new approach to power units that could potentially replace nuclear and chemical power sources for a number of space applications. These cells employ thin metallic films (order of 500 Å, using variously Ni, Pd and Ti) as cathodes with various electrolytes such as 0.5-1 molar lithium sulfate in light water. Power densities exceeding 10 W/cm3 in the thin-films have been achieved. An ultimate goal is to incorporate this thin-film technology into a ``tightly packed'' cell design where the film material occupies ~20% of the total cell volume. If this is achieved, overall power densities of ~20 W/cm3 appear feasible, opening the way to a number of potential applications ranging from distributed power units in spacecraft to advanced propulsion. .

  3. Inflation scenario driven by a low energy physics inflaton

    Science.gov (United States)

    Ferreira, J. G.; Pires, C. A. de S.; Rodrigues, J. G.; Rodrigues da Silva, P. S.

    2017-11-01

    It is a longstanding desire of cosmologists, and particle physicists as well, to connect inflation to low energy physics, culminating, for instance, in what is known as Higgs inflation. The condition for the standard Higgs boson playing the role of the inflaton, and driving sucessfully inflation, is that it couples nonminimally with gravity. Nevertheless, cosmological constraints impose that the nonminimal coupling be large. This causes the loss of perturbative unitarity in a scale of energy far below the Planck one. Our aim in this work is to point out that inflaton potential containing a particular type of trilinear coupling involving the inflaton may circumvent this problem by realizing Higgs inflation with tiny nonminimal coupling of the inflaton with gravity. We then develop the idea within a toy model and implement it in the inverse type-II seesaw mechanism for small neutrinos masses.

  4. Low-energy house in Sisimiut - Measurement equipment

    Energy Technology Data Exchange (ETDEWEB)

    Hvidthoeft Delff Andersen, P.; Rode, C.; Madsen, Henrik

    2013-08-15

    This paper documents the measurement equipment in a low-energy house in Sisimiut, Greenland. Detailed measurements are being taken on energy consumption, indoor temperatures, floor heating, ventilation, open/closed state of doors and windows, and indoors climate. Equipped with a central control unit, experiments can be designed in order to study heat dynamics of the building. It is described how to plan and execute such experiments in one apartment in the building. The building also features both a solar thermal system and extra buffer tank facilitating testing of storage strategies on the power generated by the solar thermal system. A weather station equipped with thermometer, pyranometer and anemometer is installed on the building as well. Finally, it is described how to retrieve data from an SQL server which is configured to take monthly backups. R functions have been implemented to fetch and prepare the data for time series analysis. Examples are given on the use of these. (Author)

  5. Low energy properties of the two-impurity Anderson model

    Science.gov (United States)

    Zhu, Lijun; Zhu, Jian-Xin

    2010-03-01

    We investigate the low energy properties of the two-impurity Anderson model with the complete-Fock-space numerical renormalization group method. From the calculated spectral function, correlation functions and self-energy, two energy scales are identified, as onsets of the Kondo resonance and the Fermi liquid behaviors. With the tuning of the RKKY interaction, the latter is uniformly suppressed to zero in the particle-hole symmetric case, resembling the Jones-Varma quantum critical point. In cases with the particle-hole asymmetry, an inter-impurity hybridization term is generated, which turns the quantum critical point into a crossover. Similar behaviors are found with either a direct hopping term or a local magnetic field, to lift the parity or spin degeneracies, respectively. Application to the Anderson lattice model is also presented.

  6. Low-energy photoelectron transmission through aerosol overlayers

    Science.gov (United States)

    Amanatidis, Stavros; Yoder, Bruce L.; Signorell, Ruth

    2017-06-01

    The transmission of low-energy (squalane, squalene, and di-ethyl-hexyl-sebacate shells. The photoelectrons are exclusively formed in the core of the particles by two-photon ionization. The total photoelectron yield recorded as a function of shell thicknesses (1-80 nm) shows a bi-exponential attenuation. For all substances, the damping parameter for shell thicknesses below 15 nm lies around 8 to 9 nm and is tentatively assigned to the electron attenuation length at electron kinetic energies of ≲1 eV. The significantly larger damping parameters for thick shells (>20 nm) are presumably a consequence of distorted core-shell structures. A first comparison of aerosol and traditional thin film overlayer methods is provided.

  7. Low energy electron attenuation lengths in core-shell nanoparticles.

    Science.gov (United States)

    Jacobs, Michael I; Kostko, Oleg; Ahmed, Musahid; Wilson, Kevin R

    2017-05-24

    A velocity map imaging spectrometer is used to measure photoemission from free core-shell nanoparticles, where a salt core is coated with a liquid hydrocarbon shell (i.e. squalane). By varying the radial thickness of the hydrocarbon shell, electron attenuation lengths (EALs) are determined by measuring the decay in photoemission intensity from the salt core. In squalane, electrons with kinetic energy (KE) above 2 eV are found to have EALs of 3-5 nm, whereas electrons with smaller KE (15 nm. These results (in the context of other energy-resolved EAL measurements) suggest that the energy dependent behavior of low energy electrons is similar in dielectrics when KE > 2 eV. At this energy the EALs do not appear to exhibit strong energy dependence. However, at very low KE (<2 eV), the EALs diverge and appear to be extremely material dependent.

  8. Optimization of design parameters of low-energy buildings

    Science.gov (United States)

    Vala, Jiří; Jarošová, Petra

    2017-07-01

    Evaluation of temperature development and related consumption of energy required for heating, air-conditioning, etc. in low-energy buildings requires the proper physical analysis, covering heat conduction, convection and radiation, including beam and diffusive components of solar radiation, on all building parts and interfaces. The system approach and the Fourier multiplicative decomposition together with the finite element technique offers the possibility of inexpensive and robust numerical and computational analysis of corresponding direct problems, as well as of the optimization ones with several design variables, using the Nelder-Mead simplex method. The practical example demonstrates the correlation between such numerical simulations and the time series of measurements of energy consumption on a small family house in Ostrov u Macochy (35 km northern from Brno).

  9. [Low-energy laser therapy in medial tibial stress syndrome].

    Science.gov (United States)

    Nissen, L R; Astvad, K; Madsen, L

    1994-12-05

    The effect of low-energy laser therapy on shin splints was examined in a randomized study with an unblinded design. Constripts from the Jutland Dragoon regiment with shin splints were given either active laser treatment (40 mW in 60 sec per cm tender tibia edge) or placebo laser. All patients were exempted from normal duty concerning activities like running and march. Forty-nine patients participated in the study, 23 in the laser group and 26 in the control group. From the start the study was designed to be double-blind, but by accident the code was broken towards the end of the study. We found no significant differences between the groups regarding pain visual analog score and readiness to return to active duty after 14 days.

  10. Performance Evaluation of Bluetooth Low Energy: A Systematic Review.

    Science.gov (United States)

    Tosi, Jacopo; Taffoni, Fabrizio; Santacatterina, Marco; Sannino, Roberto; Formica, Domenico

    2017-12-13

    Small, compact and embedded sensors are a pervasive technology in everyday life for a wide number of applications (e.g., wearable devices, domotics, e-health systems, etc.). In this context, wireless transmission plays a key role, and among available solutions, Bluetooth Low Energy (BLE) is gaining more and more popularity. BLE merges together good performance, low-energy consumption and widespread diffusion. The aim of this work is to review the main methodologies adopted to investigate BLE performance. The first part of this review is an in-depth description of the protocol, highlighting the main characteristics and implementation details. The second part reviews the state of the art on BLE characteristics and performance. In particular, we analyze throughput, maximum number of connectable sensors, power consumption, latency and maximum reachable range, with the aim to identify what are the current limits of BLE technology. The main results can be resumed as follows: throughput may theoretically reach the limit of ~230 kbps, but actual applications analyzed in this review show throughputs limited to ~100 kbps; the maximum reachable range is strictly dependent on the radio power, and it goes up to a few tens of meters; the maximum number of nodes in the network depends on connection parameters, on the network architecture and specific device characteristics, but it is usually lower than 10; power consumption and latency are largely modeled and analyzed and are strictly dependent on a huge number of parameters. Most of these characteristics are based on analytical models, but there is a need for rigorous experimental evaluations to understand the actual limits.

  11. Performance Evaluation of Bluetooth Low Energy: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Jacopo Tosi

    2017-12-01

    Full Text Available Small, compact and embedded sensors are a pervasive technology in everyday life for a wide number of applications (e.g., wearable devices, domotics, e-health systems, etc.. In this context, wireless transmission plays a key role, and among available solutions, Bluetooth Low Energy (BLE is gaining more and more popularity. BLE merges together good performance, low-energy consumption and widespread diffusion. The aim of this work is to review the main methodologies adopted to investigate BLE performance. The first part of this review is an in-depth description of the protocol, highlighting the main characteristics and implementation details. The second part reviews the state of the art on BLE characteristics and performance. In particular, we analyze throughput, maximum number of connectable sensors, power consumption, latency and maximum reachable range, with the aim to identify what are the current limits of BLE technology. The main results can be resumed as follows: throughput may theoretically reach the limit of ~230 kbps, but actual applications analyzed in this review show throughputs limited to ~100 kbps; the maximum reachable range is strictly dependent on the radio power, and it goes up to a few tens of meters; the maximum number of nodes in the network depends on connection parameters, on the network architecture and specific device characteristics, but it is usually lower than 10; power consumption and latency are largely modeled and analyzed and are strictly dependent on a huge number of parameters. Most of these characteristics are based on analytical models, but there is a need for rigorous experimental evaluations to understand the actual limits.

  12. Photon energy-fluence correction factor in low energy brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Paula C.G.; Yoriyaz, Hélio [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Vijande, Javier; Giménez-Alventosa, Vicent; Ballester, Facundo, E-mail: pacrisguian@gmail.com [Department of Atomic, Molecular, and Nuclear Physics and Instituto de Física Corpuscular (UV-CSIC), University of Valencia (Spain)

    2017-07-01

    The AAPM TG-43 brachytherapy dosimetry formalism has become a standard for brachytherapy dosimetry worldwide; it implicitly assumes that charged-particle equilibrium (CPE) exists for the determination of absorbed dose to water at different locations. At the time of relating dose to tissue and dose to water, or vice versa, it is usually assumed that the photon fluence in water and in tissues are practically identical, so that the absorbed dose in the two media can be related by their ratio of mass energy-absorption coefficients. The purpose of this work is to study the influence of photon energy-fluence in different media and to evaluate a proposal for energy-fluence correction factors for the conversion between dose-to-tissue (D{sub tis}) and dose-to-water (D{sub w}). State-of-the art Monte Carlo (MC) calculations are used to score photon fluence differential in energy in water and in various human tissues (muscle, adipose and bone) in two different codes, MCNP and PENELOPE, which in all cases include a realistic modeling of the {sup 125}I low-energy brachytherapy seed in order to benchmark the formalism proposed. A correction is introduced that is based on the ratio of the water-to-tissue photon energy-fluences using the large-cavity theory. In this work, an efficient way to correlate absorbed dose to water and absorbed dose to tissue in brachytherapy calculations at clinically relevant distances for low-energy photon emitting seed is proposed. The energy-fluence based corrections given in this work are able to correlate absorbed dose to tissue and absorbed dose to water with an accuracy better than 0.5% in the most critical cases. (author)

  13. Performance of low-temperature district heating for low-energy houses

    DEFF Research Database (Denmark)

    Brand, Marek; Dalla Rosa, Alessandro; Svendsen, Svend

    2010-01-01

    houses, which was previously developed and reported in the project “Development and demonstration of low-energy district heating for low energy housing” [EFP, 2007]. Two different concepts of low energy district heating substations are tested, and measurements of their performance aim to document......A Low Energy District Heating (LEDH) network supplying district heating water with temperature 50°C was built in Lærkehaven-Lystrup, Denmark, as a part of the ongoing “Energy Technology Development and Demonstration Programme” [EUDP, 2008] focused on “CO2-reduction in low energy buildings...... and communities by implementation of low temperature district heating systems”. The network supplies 40 detached Low Energy Houses built in accordance with the requirements of the Danish low energy class 1. The project aims to test and evaluate in real conditions the concept of LEDH for the supply of low energy...

  14. Final Technical Report Project: Low-Energy Photonuclear Studies at HIGS and Lund

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Gerald [George Washington Univ., Washington, DC (United States)

    2017-06-15

    This report summarizes a program of low-energy photonuclear studies at MAX-Lab in Lund (Sweden) and at the High Intensity Gamma Source (HIGS) at Duke University. A major emphasis has been on Compton scattering from deuterium in order to determine the electric and magnetic polarizabilities of the neutron. The studies at Lund utilized unpolarized photons at Egamma = 62-115 MeV to measure differential cross sections. The studies at HIGS utilized polarized and unpolarized photon beams (both linear and circular) at Egamma < 90 MeV. Polarization observables will be exploited to improve our understanding of the electric and magnetic polarizabilities, and in particular, double-polarization observables (using polarized targets) will be measured in the future to provide new information about the spin polarizabilities of the nucleon. The MAX-Lab experiments (using unpolarized photons) focused on an approved PAC proposal for Compton scattering on the deuteron aimed at making a precise determination of the electromagnetic polarizabilities of the neutron. At MAX-Lab we had three of the largest NaI detectors in the world, each capable of ~2% energy resolution. We have completed our measurements in two separate tagged photon energy ranges which overlap each other (62-97 MeV and 90-115 MeV) and the results of these experiments have been published. The photon beam at the High Intensity Gamma Source (HIGS) has several distinct advantages that make it unique: (1) ultra-high photon flux, ultimately reaching 100 MHz, (2) 100% linearly polarized photon beam, as well as circular polarization, (3) monoenergetic beam, with ~2% energy resolution, and (4) extremely low-background beam environment. Exploiting the high flux and polarization capabilities of the HIGS photon beam is central in the series of experiments being performed at this facility. Very little data exist on Compton scattering using polarized photons. We will exploit clear sensitivities in the polarization observables to the

  15. Resonances in low-energy electron elastic scattering from Fullerenes C60 through C92

    Science.gov (United States)

    Felfli, Zineb; Msezane, Alfred

    2017-04-01

    The electron affinity (EA) provides a stringent test of theory when the calculated and measured EAs are compared. A strong motivation for the fundamental investigations of low-energy electron elastic scattering from the selected fullerenes C60, C70, C74, C80, C82, C84 and C92 is the availability of high quality measured EAs. The Regge pole calculated electron elastic total cross sections for these fullerenes are found to be characterized generally by Ramsauer-Townsend (R-T) minima, shape resonances and dramatically sharp resonances manifesting stable negative ion formation. The extracted binding energies for the resultant anions agree excellently with the measured EAs of the fullerenes listed above, giving great credence to the Regge pole method and confirming that fullerenes behave like ``big atoms''. Common among all these fullerenes is the appearance of their ground state negative ions at their second R-T minima, similarly to the atomic Au case. This work was supported by U.S. DOE, Basic Energy Sciences, Office of Energy Research.

  16. A study of the isomeric dependence of low-energy (attachment: Perfluoroalkanes

    Science.gov (United States)

    Spyrou, S. M.; Hunter, S. R.; Christophorou, L. G.

    1985-07-01

    The attachment of low-energy (parent anions (autodetachment lifetimes τa >10-6 s) and dissociative attachment fragment anions were observed for these molecules in the mass spectrometric study. The relative cross sections for negative ion formation and the τa of the long-lived parent anions were measured as a function of electron energy in the mass spectrometric study. The absolute total electron attachment rate constants as a function of the mean electron energy have been measured in the swarm study and used to calculate the total electron attachment cross sections as a function of electron energy. Both studies have shown a strong dependence of dissociative and nondissociative electron attachment processes on the structure of the molecules studied. For neo-C5F12, the predominant anion is the fragment C4F-9. In contrast, for i-C4F10, i-C5F12, c-C4F8, and c-C5F10, the parent anions are stronger than any of the fragment anions. Energetic considerations have been employed to identify fragmentation mechanisms of the negative ion states (NISs) leading to the formation of the observed fragment anions and to deduce some thermochemical data. The positions of the NISs, the observed differences in the cross sections for parent and fragment anion formation, and the types of the fragment anions formed for the various molecules are discussed.

  17. ACADEMIC TRAINING: Low Energy Experiments that Measure Fundamental Constants and Test Basic Symmetries

    CERN Multimedia

    Françoise Benz

    2002-01-01

    17, 18, 19 , 21 June LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Low Energy Experiments that Measure Fundamental Constants and Test Basic Symmetries by G. GABRIELSE / Professor of Physics and Chair of the Harvard Physics Department, Spokesperson for the ATRAP Collaboration Lecture 1: Particle Traps: the World's Tiniest Accelerators A single elementary particle, or a single ion, can be confined in a tiny accelerator called a particle trap. A single electron was held this way for more than ten months, and antiprotons for months. Mass spectroscopy of exquisite precision is possible with such systems. CERN's TRAP Collaboration thereby compared the charge-to-mass ratios of the antiproton and proton to a precision of 90 parts per trillion, by far the most stringent CPT test done with a baryon system. The important ratio of the masses of the electron and proton have been similarly measured, as have a variety of ions masses, and the neutron mass is most accurately known from such measurements. An i...

  18. Deuterium retention in tungsten and tungsten-tantalum alloys exposed to high-flux deuterium plasmas

    NARCIS (Netherlands)

    Zayachuk, Y.; Hoen, M. H. J. 't; van Emmichoven, P. A. Zeijlma; Uytdenhouwen, I.; Van Oost, G.

    2012-01-01

    A direct comparison of deuterium retention in samples of tungsten and two grades of tungsten-tantalum alloys-W-1% Ta and W-5% Ta, exposed to deuterium plasmas (ion flux similar to 10(24) m(-2) s(-1), ion energy at the biased target similar to 50 eV) at the plasma generator Pilot-PSI was performed

  19. Review of lattice results concerning low energy particle physics

    CERN Document Server

    Colangelo, Gilberto; Juttner, Andreas; Lellouch, Laurent; Leutwyler, Heinrich; Lubicz, Vittorio; Necco, Silvia; Sachrajda, Christopher T; Simula, Silvano; Vladikas, Anastassios; Wenger, Urs; Wittig, Hartmut

    2011-01-01

    We review lattice results relevant for pion and kaon physics with the aim of making them easily accessible to the particle physics community. Specifically, we review the determination of the light-quark masses, the form factor f_+(0), relevant for the semileptonic K -> pi transition at zero momentum transfer as well as the ratio f_K/f_pi of decay constants and discuss the consequences for the elements V_{us} and V_{ud} of the CKM matrix. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2)_LxSU(2)_R and SU(3)_LxSU(3)_R Chiral Perturbation Theory and review the determination of the B_K parameter of neutral kaon mixing. We introduce quality criteria and use these when forming averages. Although subjective and imperfect, these criteria may help the reader to judge different aspects of current lattice computations. Our main results are summarized in section 1.2, but we stress the importance of the detailed discussion that underlies these results and constitute...

  20. Analysis of Latency Performance of Bluetooth Low Energy (BLE Networks

    Directory of Open Access Journals (Sweden)

    Keuchul Cho

    2014-12-01

    Full Text Available Bluetooth Low Energy (BLE is a short-range wireless communication technology aiming at low-cost and low-power communication. The performance evaluation of classical Bluetooth device discovery have been intensively studied using analytical modeling and simulative methods, but these techniques are not applicable to BLE, since BLE has a fundamental change in the design of the discovery mechanism, including the usage of three advertising channels. Recently, there several works have analyzed the topic of BLE device discovery, but these studies are still far from thorough. It is thus necessary to develop a new, accurate model for the BLE discovery process. In particular, the wide range settings of the parameters introduce lots of potential for BLE devices to customize their discovery performance. This motivates our study of modeling the BLE discovery process and performing intensive simulation. This paper is focused on building an analytical model to investigate the discovery probability, as well as the expected discovery latency, which are then validated via extensive experiments. Our analysis considers both continuous and discontinuous scanning modes. We analyze the sensitivity of these performance metrics to parameter settings to quantitatively examine to what extent parameters influence the performance metric of the discovery processes.

  1. Wettability Modification of Nanomaterials by Low-Energy Electron Flux

    Directory of Open Access Journals (Sweden)

    Torchinsky I

    2009-01-01

    Full Text Available Abstract Controllable modification of surface free energy and related properties (wettability, hygroscopicity, agglomeration, etc. of powders allows both understanding of fine physical mechanism acting on nanoparticle surfaces and improvement of their key characteristics in a number of nanotechnology applications. In this work, we report on the method we developed for electron-induced surface energy and modification of basic, related properties of powders of quite different physical origins such as diamond and ZnO. The applied technique has afforded gradual tuning of the surface free energy, resulting in a wide range of wettability modulation. In ZnO nanomaterial, the wettability has been strongly modified, while for the diamond particles identical electron treatment leads to a weak variation of the same property. Detailed investigation into electron-modified wettability properties has been performed by the use of capillary rise method using a few probing liquids. Basic thermodynamic approaches have been applied to calculations of components of solid–liquid interaction energy. We show that defect-free, low-energy electron treatment technique strongly varies elementary interface interactions and may be used for the development of new technology in the field of nanomaterials.

  2. High-Resolution Measurements of Low-Energy Conversion Electrons

    CERN Multimedia

    Gizon, A; Putaux, J

    2002-01-01

    Measurements of low-energy internal conversion electrons have been performed with high energy resolution in some N = 105 odd and odd-odd nuclei using a semi-circular spectrograph associated to a specific tape transport system. These experiments aimed to answer the following questions~: \\begin{itemize} \\item Do M3 isomeric transitions exist in $^{183}$Pt and $^{181}$Os, isotones of $^{184}$Au~? \\item Are the neutron configurations proposed to describe the isomeric and ground states of $^{184}$Au right or wrong~? \\item Does it exist an isomeric state in $^{182}$Ir, isotone of $^{181}$Os, $^{183}$Pt and $^{184}$Au~? \\item What are the spin and parity values of the excited states of $^{182}$Ir~? \\end{itemize} In $^{183}$Pt, the 35.0 keV M3 isomeric transition has been clearly observed and the reduced transition probability has been determined. The deduced hindrance factor is close to that observed in the neighbouring odd-odd $^{184}$Au nucleus. This confirms the neutron configurations previously proposed for the ...

  3. Ultra-low-energy analog straintronics using multiferroic composites

    Science.gov (United States)

    Roy, Kuntal

    2014-03-01

    Multiferroic devices, i.e., a magnetostrictive nanomagnet strain-coupled with a piezoelectric layer, are promising as binary switches for ultra-low-energy digital computing in beyond Moore's law era [Roy, K. Appl. Phys. Lett. 103, 173110 (2013), Roy, K. et al. Appl. Phys. Lett. 99, 063108 (2011), Phys. Rev. B 83, 224412 (2011), Scientific Reports (Nature Publishing Group) 3, 3038 (2013), J. Appl. Phys. 112, 023914 (2012)]. We show here that such multiferroic devices, apart from performing digital computation, can be also utilized for analog computing purposes, e.g., voltage amplification, filter etc. The analog computing capability is conceived by considering that magnetization's mean orientation shifts gradually although nanomagnet's potential minima changes abruptly. Using tunneling magnetoresistance (TMR) measurement, a continuous output voltage while varying the input voltage can be produced. Stochastic Landau-Lifshitz-Gilbert (LLG) equation in the presence of room-temperature (300 K) thermal fluctuations is solved to demonstrate the analog computing capability of such multiferroic devices. This work was supported in part by FAME, one of six centers of STARnet, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.

  4. Low energy consumption vortex wave flow membrane bioreactor.

    Science.gov (United States)

    Wang, Zhiqiang; Dong, Weilong; Hu, Xiaohong; Sun, Tianyu; Wang, Tao; Sun, Youshan

    2017-11-01

    In order to reduce the energy consumption and membrane fouling of the conventional membrane bioreactor (MBR), a kind of low energy consumption vortex wave flow MBR was exploited based on the combination of biofilm process and membrane filtration process, as well as the vortex wave flow technique. The experimental results showed that the vortex wave flow state in the membrane module could be formed when the Reynolds number (Re) of liquid was adjusted between 450 and 1,050, and the membrane flux declined more slowly in the vortex wave flow state than those in the laminar flow state and turbulent flow state. The MBR system was used to treat domestic wastewater under the condition of vortex wave flow state for 30 days. The results showed that the removal efficiency for CODcr and NH3-N was 82% and 98% respectively, and the permeate quality met the requirement of 'Water quality standard for urban miscellaneous water consumption (GB/T 18920-2002)'. Analysis of the energy consumption of the MBR showed that the average energy consumption was 1.90 ± 0.55 kWh/m3 (permeate), which was only two thirds of conventional MBR energy consumption.

  5. The low-energy frontier of particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckel, Joerg [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-02-15

    Most embeddings of the Standard Model into a more unified theory, in particular the ones based on supergravity or superstrings, predict the existence of a hidden sector of particles which have only very weak interactions with the visible sector Standard Model particles. Some of these exotic particle candidates (such as e.g. ''axions'', ''axion-like particles'' and ''hidden U(1) gauge bosons'') may be very light, with masses in the sub-eV range, and have very weak interactions with photons. Correspondingly, these very weakly interacting sub-eV particles (WISPs) may lead to observable effects in experiments (as well as in astrophysical and cosmological observations) searching for light shining through a wall, for changes in laser polarisation, for non-linear processes in large electromagnetic fields and for deviations from Coulomb's law. We present the physics case and a status report of this emerging low-energy frontier of fundamental physics. (orig.)

  6. E1 and M1 strength functions at low energy

    Science.gov (United States)

    Schwengner, Ronald; Massarczyk, Ralph; Bemmerer, Daniel; Beyer, Roland; Junghans, Arnd R.; Kögler, Toni; Rusev, Gencho; Tonchev, Anton P.; Tornow, Werner; Wagner, Andreas

    2017-09-01

    We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.

  7. Low energy observables and exclusive production with the ATLAS Detector

    CERN Document Server

    Martin, Tim; The ATLAS collaboration

    2017-01-01

    Low energy phenomena have been studied in detail at the LHC, providing important input for improving models of non-perturbative QCD effects. The ATLAS collaboration has performed several new measurements in this sector: We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV. The results are corrected for detector effects and compared to predictions from various Monte Carlo generators. In addition, we present studies on the correlated hadron production, as they are an important source for information on the early stages of hadron formation. In particular, an analysis of the momentum difference between charged hadrons in high–energy proton–proton collisions is performed in order to study coherent particle production. The results are compared to the predictions of a helical QCD string fragmenting model. In the absence of forward proton tagging, exclusive processes can be distinguished in the ...

  8. Collisions of low-energy electrons with cyclohexane.

    Science.gov (United States)

    Barbosa, Alessandra Souza; Bettega, Márcio H F

    2014-12-28

    We report calculated cross sections for elastic scattering of low-energy electrons by cyclohexane (c-C6H12). We employed the Schwinger multichannel method implemented with norm-conserving pseudopotentials in the static-exchange and static-exchange plus polarization approximations, for impact energies up to 30 eV. We compare our calculated integral cross section with experimental total cross sections available in the literature. We also compare our calculated differential cross sections (DCSs) with experimental results for benzene and experimental and theoretical results for 1,4-dioxane, in order to investigate the similarities between those molecules under electron collisions. Although benzene is a cyclic six-carbon molecule, as cyclohexane, we found that the differential cross sections of the latter are more similar to those of 1,4-dioxane than those of benzene. These similarities suggest that the geometry may play an important role in the behavior of the DCSs of these molecules. Our integral cross section displays a broad structure at around 8.5 eV, in agreement with the total cross section experimental data of 8 eV and vibrational excitation data of 7.5 eV. The present integral cross section also shows the presence of a Ramsauer-Townsend minimum at around 0.12 eV. In general, our integral cross section shows a qualitative agreement with the experimental total cross section.

  9. Review of lattice results concerning low-energy particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, S. [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Aoki, Y. [Nagoya University, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya (Japan); Brookhaven National Laboratory, RIKEN BNL Research Center, Upton, NY (United States); Bernard, C. [Washington University, Department of Physics, Saint Louis, MO (United States); Blum, T. [Brookhaven National Laboratory, RIKEN BNL Research Center, Upton, NY (United States); University of Connecticut, Physics Department, Storrs, CT (United States); Colangelo, G.; Leutwyler, H.; Necco, S.; Wenger, U. [Institut fuer theoretische Physik, Universitaet Bern, Albert Einstein Center for Fundamental Physics, Bern (Switzerland); Della Morte, M. [University of Southern Denmark, CP3-Origins and Danish IAS, Odense M (Denmark); IFIC (CSIC), Paterna (Spain); Duerr, S. [Bergische Universitaet Wuppertal, Wuppertal (Germany); Juelich Supercomputing Center, Juelich (Germany); El-Khadra, A.X. [University of Illinois, Department of Physics, Urbana, IL (United States); Fukaya, H.; Onogi, T. [Osaka University, Department of Physics, Osaka (Japan); Horsley, R. [University of Edinburgh, School of Physics, Edinburgh (United Kingdom); Juettner, A.; Sachrajda, C.T. [University of Southampton, School of Physics and Astronomy, Southampton (United Kingdom); Kaneko, T. [High Energy Accelerator Research Organization (KEK), Ibaraki (Japan); Laiho, J. [University of Glasgow, SUPA, Department of Physics and Astronomy, Glasgow (United Kingdom); Syracuse University, Department of Physics, Syracuse, New York (United States); Lellouch, L. [Aix-Marseille Universite, CNRS, CPT, UMR 7332, Marseille (France); Universite de Toulon, CNRS, CPT, UMR 7332, La Garde (France); Lubicz, V. [Universita Roma Tre, Dipartimento di Matematica e Fisica, Rome (Italy); Sezione di Roma Tre, INFN, Rome (Italy); Lunghi, E. [Indiana University, Physics Department, Bloomington, IN (United States); Pena, C. [Universidad Autonoma de Madrid, Instituto de Fisica Teorica UAM/CSIC and Departamento de Fisica Teorica, Madrid (Spain); Sharpe, S.R. [University of Washington, Physics Department, Seattle, WA (United States); Simula, S. [Sezione di Roma Tre, INFN, Rome (Italy); Sommer, R. [NIC rate at DESY, Zeuthen (Germany); Water, R.S.V. de [Fermi National Accelerator Laboratory, Batavia, IL (United States); Vladikas, A. [Universita di Roma Tor Vergata, INFN, Sezione di Tor Vergata, c/o Dipartimento di Fisica, Rome (Italy); Wittig, H. [University of Mainz, PRISMA Cluster of Excellence, Institut fuer Kernphysik and Helmholtz Institute Mainz, Mainz (Germany); Collaboration: FLAG Working Group

    2014-09-15

    We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the lightquark masses, the form factor f{sub +}(0), arising in semileptonic K → π transition at zero momentum transfer, as well as the decay-constant ratio f{sub K}/f{sub π} of decay constants and its consequences for the CKM matrix elements V{sub us} and V{sub ud}. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2){sub L} x SU(2){sub R} andSU(3)L{sub L} x SU(3){sub R} Chiral Perturbation Theory and review the determination of the BK parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on D- and B-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant α{sub s}. (orig.)

  10. Sgoldstino-less inflation and low energy SUSY breaking

    Science.gov (United States)

    Argurio, Riccardo; Coone, Dries; Heurtier, Lucien; Mariotti, Alberto

    2017-07-01

    We assess the range of validity of sgoldstino-less inflation in a scenario of low energy supersymmetry breaking. We first analyze the consistency conditions that an effective theory of the inflaton and goldstino superfields should satisfy in order to be faithfully described by a sgoldstino-less model. Enlarging the scope of previous studies, we investigate the case where the effective field theory cut-off, and hence also the sgoldstino mass, are inflaton-dependent. We then introduce a UV complete model where one can realize successfully sgoldstino-less inflation and gauge mediation of supersymmetry breaking, combining the α-attractor mechanism and a weakly coupled model of spontaneous breaking of supersymmetry. In this class of models we find that, given current limits on superpartner masses, the gravitino mass has a lower bound of the order of the MeV, i.e. we cannot reach very low supersymmetry breaking scales. On the plus side, we recognize that in this framework, one can derive the complete superpartner spectrum as well as compute inflation observables, the reheating temperature, and address the gravitino overabundance problem. We then show that further constraints come from collider results and inflation observables. Their non trivial interplay seems a staple feature of phenomenological studies of supersymmetric inflationary models.

  11. Dynamics of anion-molecule reactions at low energy

    Energy Technology Data Exchange (ETDEWEB)

    Mikosch, J.

    2007-11-15

    Anion-molecule reactions must find their way through deeply bound entrance and exit channel complexes separated by a central barrier. This results in low reaction rates and rich dynamics since direct pathways compete with the formation of transient intermediates. In this thesis we examine the probability of proton transfer to a small anion and transient lifetimes of a thermoneutral bimolecular nucleophilic substitution (S{sub N}2) reaction at well defined variable temperature down to 8 Kelvin in a multipole trap. The observed strong inverse temperature dependence is attributed to the deficit of available quantum states in the entrance channel at decreasing temperature. Furthermore we investigate scattering dynamics of S{sub N}2 reactions at defined relative energy between 0.4 and 10 eV by crossed beam slice imaging. A weakly exothermic reaction with high central barrier proceeds via an indirect, complex-mediated mechanism at low relative energies featuring high internal product excitation in excellent quantitative agreement with a statistical model. In contrast, direct backward scattering prevails for higher energies with product velocities close to the kinematical cutoff. For a strongly exothermic reaction, competing S{sub N}2-, dihalide- and proton transfer-channels are explored which proceed by complex mediation for low energy and various rebound-, grazing- and collision induced bond rupture-mechanisms at higher energy. From our data and a collaboration with theory we identify a new indirect roundabout S{sub N}2 mechanism involving CH{sub 3}-rotation. (orig.)

  12. Review of lattice results concerning low-energy particle physics.

    Science.gov (United States)

    Aoki, S; Aoki, Y; Bernard, C; Blum, T; Colangelo, G; Della Morte, M; Dürr, S; El-Khadra, A X; Fukaya, H; Horsley, R; Jüttner, A; Kaneko, T; Laiho, J; Lellouch, L; Leutwyler, H; Lubicz, V; Lunghi, E; Necco, S; Onogi, T; Pena, C; Sachrajda, C T; Sharpe, S R; Simula, S; Sommer, R; Van de Water, R S; Vladikas, A; Wenger, U; Wittig, H

    We review lattice results related to pion, kaon, [Formula: see text]- and [Formula: see text]-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor [Formula: see text], arising in semileptonic [Formula: see text] transition at zero momentum transfer, as well as the decay-constant ratio [Formula: see text] of decay constants and its consequences for the CKM matrix elements [Formula: see text] and [Formula: see text]. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of [Formula: see text] and [Formula: see text] Chiral Perturbation Theory and review the determination of the [Formula: see text] parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on [Formula: see text]- and [Formula: see text]-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant [Formula: see text].

  13. Analysis of latency performance of bluetooth low energy (BLE) networks.

    Science.gov (United States)

    Cho, Keuchul; Park, Woojin; Hong, Moonki; Park, Gisu; Cho, Wooseong; Seo, Jihoon; Han, Kijun

    2014-12-23

    Bluetooth Low Energy (BLE) is a short-range wireless communication technology aiming at low-cost and low-power communication. The performance evaluation of classical Bluetooth device discovery have been intensively studied using analytical modeling and simulative methods, but these techniques are not applicable to BLE, since BLE has a fundamental change in the design of the discovery mechanism, including the usage of three advertising channels. Recently, there several works have analyzed the topic of BLE device discovery, but these studies are still far from thorough. It is thus necessary to develop a new, accurate model for the BLE discovery process. In particular, the wide range settings of the parameters introduce lots of potential for BLE devices to customize their discovery performance. This motivates our study of modeling the BLE discovery process and performing intensive simulation. This paper is focused on building an analytical model to investigate the discovery probability, as well as the expected discovery latency, which are then validated via extensive experiments. Our analysis considers both continuous and discontinuous scanning modes. We analyze the sensitivity of these performance metrics to parameter settings to quantitatively examine to what extent parameters influence the performance metric of the discovery processes.

  14. Early Forest Fire Detection Using Low Energy Hydrogen Sensors

    Directory of Open Access Journals (Sweden)

    Jürgen Müller

    2016-08-01

    Full Text Available The North-east German Lowlands is a region with one of the highest forest fire risks in Europe. In order to keep damage levels as low as possible, it is important to have an effective early warning system. Such a system is being developed on the basis of a hydrogen sensor, which makes it possible to detect a smouldering forest fire before the development of open flames. The prototype hydrogen sensor produced at the Humboldt University Berlin has a metal/ solid electrolyte/insulator/ semiconductor (MEIS structure, which allows cost-effective production. Due to the low energy consumption, an autarchic working unit could be installed in the forest. Field trials have shown that it is possible to identify a forest fire in its early stages when hydrogen concentrations are still low. A significant change in the signal due to a fire was measured at a distance of about 100m. In view of the potential impacts of climate change, the innovative pre-ignition warning system is an important early diagnosis and monitoring module for the protection of the forests.

  15. Inelastic pion scattering by /sup 13/C at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in /sup 13/C at an incident energy of 65 MeV. The data include results from both ..pi../sup +/ and ..pi../sup -/ measurements. In addition, ..pi../sup -/ measurements were made at T/sub ..pi../ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2/sup +/ state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs.

  16. Testing SO(10)-inspired leptogenesis with low energy neutrino experiments

    CERN Document Server

    Di Bari, Pasquale

    2011-01-01

    We extend the results of a previous analysis of ours showing that, when both heavy and light flavour effects are taken into account, successful minimal (type I + thermal) leptogenesis with SO(10)-inspired relations is possible. Barring fine tuned choices of the parameters, these relations enforce a hierarchical RH neutrino mass spectrum that results into a final asymmetry dominantly produced by the next-to-lightest RH neutrino decays (N_2 dominated leptogenesis). We present the constraints on the whole set of low energy neutrino parameters. Allowing a small misalignment between the Dirac basis and the charged lepton basis as in the quark sector, the allowed regions enlarge and the lower bound on the reheating temperature gets relaxed to values as low as ~ 10^10 GeV. It is confirmed that for normal ordering (NO) there are two allowed ranges of values for the lightest neutrino mass: m_1 \\simeq (1-5)\\times 10^-3 eV and m_1\\simeq (0.03-0.1) eV. For m_1\\lesssim 0.01 eV the allowed region in the plane theta_13-thet...

  17. Low energy electron bombardment induced surface contamination of Ru mirrors

    Science.gov (United States)

    Al-Ajlony, A.; Kanjilal, A.; Catalfano, M.; Harilal, S. S.; Hassanein, A.; Rice, B.

    2012-03-01

    The impact of secondary electrons induced contamination of the Ru surface was investigated. Mirror-like Ru sample was bombarded with low energy (100 eV) electrons and the change in surface chemistry was investigated using X-ray photoelectron spectroscopy (XPS).Along with XPS studies the corresponding effect on in-situ EUV reflectivity was examined by exposing the Ru surface to photons at a wavelength of 13.5 nm in an ultrahigh vacuum chamber. Detailed XPS analyses showed a sudden increase in carbon concentrations on the Ru surface in the first 60 min, followed by a slow but linear growth in carbon concentration. In parallel, a noticeable decrease in water content was observed during the time of electrons irradiation along with slight oxidation of pure Ru surface. All chemical changes were discussed in terms of the electrons bombardment mediated dissociation of water and hydrocarbon molecules. A time dependent EUV reflectivity measurements show insignificant change in reflectivity up to 510 min of electrons bombardment. The impact of water molecules on the Ru surface and the accumulation of carbon through dissociation of residual hydrocarbons is discussed in details.

  18. AES based secure low energy adaptive clustering hierarchy for WSNs

    Science.gov (United States)

    Kishore, K. R.; Sarma, N. V. S. N.

    2013-01-01

    Wireless sensor networks (WSNs) provide a low cost solution in diversified application areas. The wireless sensor nodes are inexpensive tiny devices with limited storage, computational capability and power. They are being deployed in large scale in both military and civilian applications. Security of the data is one of the key concerns where large numbers of nodes are deployed. Here, an energy-efficient secure routing protocol, secure-LEACH (Low Energy Adaptive Clustering Hierarchy) for WSNs based on the Advanced Encryption Standard (AES) is being proposed. This crypto system is a session based one and a new session key is assigned for each new session. The network (WSN) is divided into number of groups or clusters and a cluster head (CH) is selected among the member nodes of each cluster. The measured data from the nodes is aggregated by the respective CH's and then each CH relays this data to another CH towards the gateway node in the WSN which in turn sends the same to the Base station (BS). In order to maintain confidentiality of data while being transmitted, it is necessary to encrypt the data before sending at every hop, from a node to the CH and from the CH to another CH or to the gateway node.

  19. A low energy neutrino factory with non-magnetic detectors

    CERN Document Server

    Huber, Patrick

    2008-01-01

    We show that a very precise neutrino/anti-neutrino event separation is not mandatory to cover the physics program of a low energy neutrino factory and thus non-magnetized detectors like water Cerenkov or liquid Argon detectors can be used. We point out, that oscillation itself strongly enhances the signal to noise ratio of a wrong sign muon search, provided there is sufficiently accurate neutrino energy reconstruction. Further, we argue that apart from a magnetic field, other means to distinguish neutrino from anti-neutrino events (at least statistically) can be explored. Combined with the fact that non-magnetic detectors potentially can be made very big, we show that modest neutrino/anti-neutrino separations at the level of 50% to 90% are sufficient to obtain good sensitivity to CP violation and the neutrino mass hierarchy for $\\sin^22\\theta_{13}>10^{-3}$. These non-magnetized detectors have a rich physics program outside the context of a neutrino factory, including topics like supernova neutrinos and proton...

  20. Low-energy-electron scattering by CH3CN

    Science.gov (United States)

    Maioli, Leticia S.; Bettega, Márcio H. F.

    2017-12-01

    We report integral and differential cross sections for the elastic scattering of low-energy electrons by methyl cyanide (CH3CN), also known as acetonitrile. The cross sections were computed using the Schwinger multichannel method implemented with pseudopotentials. The fixed-nuclei scattering calculations were performed in the static-exchange and static-exchange plus polarization approximations for energies up to 15 eV. In our calculations with polarization effects, we found a π * shape resonance at around 2.22 eV and a broad structure associated to a σ * shape resonance at around 7 eV. The low-lying resonance was assigned to the electron capture by the two-fold degenerate π * orbital of the E symmetry of C 3 v group; the second was assigned to a σ * shape resonance in the A 1 symmetry. We compared our cross sections with theoretical results and experimental data available in the literature, and in general we found good agreement for the positions of the two resonances.