WorldWideScience

Sample records for reflected pickup ions

  1. Inner Source Pickup Ions Observed by Ulysses

    Science.gov (United States)

    Gloeckler, G.

    2016-12-01

    The existence of an inner source of pickup ions close to the Sun was proposed in order to explain the unexpected discovery of C+ in the high-speed polar solar wind. Here I report on detailed analyses of the composition and the radial and latitudinal variations of inner source pickup ions measured with the Solar Wind Ion Composition Spectrometer on Ulysses from 1991 to 1998, approaching and during solar minimum. We find that the C+ intensity drops off with radial distance R as R-1.53, peaks at mid latitudes and drops to its lowest value in the ecliptic. Not only was C+ observed, but also N+, O+, Ne+, Na+, Mg+, Ar+, S+, K+, CH+, NH+, OH+, H2O+, H3O+, MgH+, HCN+, C2H4+, SO+ and many other singly-charged heavy ions and molecular ions. The measured velocity distributions of inner source pickup C+ and O+ indicate that these inner source pickup ions are most likely produced by charge exchange, photoionization and electron impact ionization of neutrals close to the Sun (within 10 to 30 solar radii). Possible causes for the unexpected latitudinal variations and the neutral source(s) producing the inner source pickup ions as well as plausible production mechanisms for inner source pickup ions will be discussed.

  2. MAVEN Pickup Ion Constraints on Mars Neutral Escape

    Science.gov (United States)

    Rahmati, A.; Larson, D. E.; Cravens, T.; Lillis, R. J.; Dunn, P.; Halekas, J. S.; McFadden, J. P.; Mitchell, D. L.; Thiemann, E.; Connerney, J. E. P.; DiBraccio, G. A.; Espley, J. R.; Eparvier, F. G.

    2017-12-01

    Mars is currently losing its atmosphere mainly due to the escape of neutral hydrogen and oxygen. Directly measuring the rate of escaping neutrals is difficult, because the neutral density in the Mars exosphere is dominated, up to several Martian radii, by atoms that are gravitationally bound to the planet. Neutral atoms in the Martian exosphere, however, can get ionized, picked up, and accelerated by the solar wind motional electric field and energized to energies high enough for particle detectors to measure them. The MAVEN SEP instrument detects O+ pickup ions that are created at altitudes where the escaping part of the exosphere is dominant. Fluxes of these ions reflect neutral densities in the distant exosphere of Mars, allowing us to constrain neutral oxygen escape rates. The MAVEN SWIA and STATIC instruments measure pickup H+ and O+ created closer to Mars; comparisons of these data with models can be used to constrain exospheric hot O and thermal H densities and escape rates. In this work, pickup ion measurements from SEP, SWIA, and STATIC, taken during the first 3 Earth years of the MAVEN mission, are compared to the outputs of a pickup ion model to constrain the variability of neutral escape at Mars. The model is based on data from six MAVEN instruments, namely, MAG providing magnetic field used in calculating pickup ion trajectories, SWIA providing solar wind velocity as well as 3D pickup H+ and O+ spectra, SWEA providing solar wind electron spectrum used in electron impact ionization rate calculations, SEP providing pickup O+ spectra, STATIC providing mass resolved 3D pickup H+ and O+ spectra, and EUVM providing solar EUV spectra used in photoionization rate calculations. A variability of less than a factor of two is observed in hot oxygen escape rates, whereas thermal escape of hydrogen varies by an order of magnitude with Mars season. This hydrogen escape variability challenges our understanding of the H cycle at Mars, but is consistent with other

  3. Pick-up ion energization at the termination shock

    Energy Technology Data Exchange (ETDEWEB)

    Gary, S Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Wu, Pin [BOSTON UNIV.; Schwadron, N A [BOSTON UNIV.

    2009-01-01

    One-dimensional hybrid simulations are used to investigate how pickup ions are energized at the perpendicular termination shock. Contrary to previous models based on pickup ion energy gain by repeated crossings of the shock front (shock surfing) or due to a reforming shock front, the present simulations show that pickup ion energy gain involves a gyro-phasedependent interaction with the inhomogeneous motional electric field at the shock. The process operates at all relative concentrations of pickup ion density.

  4. Cometary pick-up ions observed near Giacobini-Zinner

    Science.gov (United States)

    Gloeckler, G.; Hovestadt, D.; Ipavich, F. M.; Scholer, M.; Klecker, B.

    1986-01-01

    The number and energy density of cometary water-group ions observed near Comet Giacobini-Zinner are derived using the rest-frame distribution functions. The data reveal that density profiles of inbound and outbound passes and their shape correlate with pick-up ion production model predictions. The lose rate and production rate of water-group cometary molecules calculated from predicted and measured density profiles are 2 x 10 to the -6th/sec and 2.6 x 10 to the 28th/sec respectively. The shapes of the distribution functions are examined to study the solar wind/cometary ions interaction process.

  5. Cassini CAPS Identification of Pickup Ion Compositions at Rhea

    Science.gov (United States)

    Desai, R. T.; Taylor, S. A.; Regoli, L. H.; Coates, A. J.; Nordheim, T. A.; Cordiner, M. A.; Teolis, B. D.; Thomsen, M. F.; Johnson, R. E.; Jones, G. H.; Cowee, M. M.; Waite, J. H.

    2018-02-01

    Saturn's largest icy moon, Rhea, hosts a tenuous surface-sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing CO2+ during both the R1 and R1.5 encounters. Accounting for this nongyrotropy, we show that these possess comparable along-track densities of ˜2 × 10-3 cm-3. Negatively charged pickup ions, also detected during R1, are surprisingly shown as consistent with mass 26 ± 3 u which we suggest are carbon-based compounds, such as CN-, C2H-, C2-, or HCO-, sputtered from carbonaceous material on the moon's surface. The negative ions are calculated to possess along-track densities of ˜5 × 10-4 cm-3 and are suggested to derive from exogenic compounds, a finding consistent with the existence of Rhea's dynamic CO2 exosphere and surprisingly low O2 sputtering yields. These pickup ions provide important context for understanding the exospheric and surface ice composition of Rhea and of other icy moons which exhibit similar characteristics.

  6. Pick-Up Ion Instabilities at Planetary Magnetospheres

    Science.gov (United States)

    Strangeway, Robert J.; Sharber, James (Technical Monitor)

    2001-01-01

    This effort involved the analysis of low frequency waves as observed by the Galileo spacecraft near the Galilean moon, Io. Io is a significant source of material, especially SO2, and various products of dissociation, and further these atoms and molecules are readily ionized. The initial velocity of the ions is essentially that of the neutral species, i.e., the Keplerian velocity. The plasma, on the other hand is co-rotating, and there is a differential flow of the order 57 km/s between the plasma and the neutral particles. Thus pick-up ion instabilities are Rely to occur within the Jovian magnetosphere. Indeed, magnetometer observations from the Galileo spacecraft clearly show ion cyclotron waves that have been identified with a large variety of plasma species, such as O+, S++ (which has the same gyro-frequency as O+), S+, and SO2+. Typically, however, the dominant frequency is near the SO2+ gyro-frequency. The research effort was originally planned to be a team effort between Robert J. Strangeway as the Principal Investigator, and Debbie Huddleston, who was an Assistant Research Geophysicist at UCLA. Unfortunately, Dr. Huddleston took a position within Industry. The effort was therefore descoped, and Dr. Strangeway instead pursued a collaboration with Dr. Xochitl Blanco-Cano, of the Instituto de Geofisica, Universidad Nacional Autonoma de Mexico. This has proved to be a productive collaboration, with several papers and publications arising out of the effort. The magnetic field oscillations near lo generally fall into two types: ion cyclotron waves, with frequencies near an ion gyro-frequency, and lower frequency mirror-mode waves. The ion cyclotron waves are mainly transverse, and frequently propagate along the ambient magnetic field. The mirror-mode waves are compressional waves, and they have essentially zero frequency in the plasma rest frame. One of the purposes of our investigation is to understand what controls the types of wave modes that occur, since both

  7. ENERGETIC NEUTRAL ATOMS: AN ADDITIONAL SOURCE FOR HELIOSPHERIC PICKUP IONS

    International Nuclear Information System (INIS)

    Bochsler, Peter; Moebius, Eberhard

    2010-01-01

    Recently, Schwadron and McComas discussed the possibility of inner source pickup particles originating from the ionization of energetic neutral atoms (ENAs), based on new data from the IBEX mission. This proposition has some interesting features, namely, it might be able to explain why inner source pickup ions (PUIs) have a composition resembling solar abundances and show no indication of overabundance of refractory elements, although this should be expected, if the conventional explanation of solar wind-dust interaction for the origin of this heliospheric component were correct. In this Letter, we explore further consequences for ENA-related PUIs and investigate their velocity distributions. We conclude that this model will not reproduce the observed velocity distributions of inner source PUIs and point out a substantial deviation in their composition. However, it seems likely that the ionization of ENAs as observed with IBEX could contribute a significant amount of heliospheric suprathermal tail ions. Some possible consequences of our investigation for heliospheric particle populations are briefly discussed.

  8. Imprints from the solar cycle on the helium atom and helium pickup ion distributions

    Directory of Open Access Journals (Sweden)

    D. Rucinski

    Full Text Available Neutral interstellar helium atoms penetrate into the solar system almost unaffected by gas–plasma interactions in the heliospheric interface region, and thus can be considered as carriers of original information on the basic parameters (like density, temperature, bulk velocity of the Very Local Interstellar Medium (VLISM. Such information can nowadays be derived from analysis of data obtained from different experimental methods: in situ measurements of He atoms (Ulysses, observations of the solar backscattered He 584 A radiation (EUVE, in situ measurements of He + pickup ions (AMPTE, Ulysses, Wind, SOHO, ACE. In view of the current coordinated international ISSI campaign devoted to the study of the helium focusing cone structure and its evolution, we analyze expected variations of neutral He density, of He + pickup fluxes and of their phase space distributions at various phases of the solar activity cycle based on a realistic time-dependent modelling of the neutral helium and He + pickup ion distributions, which reflect solar cycle-induced variations of the photoionization rate. We show that the neutral helium density values are generally anticorrelated with the solar activity phase and in extreme cases (near the downwind axis the maximum-to-minimum density ratio may even exceed factors of ~ 3 at 1 AU. We also demonstrate that in the upwind hemisphere (at 1 AU and beyond the He + fluxes are correlated with the solar cycle activity, whereas on the downwind side the maximum of the expected flux up to distances of ~ 3 AU occurs around solar minimum epoch, and only further away does the correlation with solar activity become positive. Finally, we present the response of the phase space distribution spectra of He + pickup ions (in the solar wind frame for different epochs of the solar cycle and heliocentric distances from 1 to 5 AU covering the range of Ulysses, Wind and ACE observations.

    Key words. Solar physics, astrophysics and astronomy

  9. Imprints from the solar cycle on the helium atom and helium pickup ion distributions

    Directory of Open Access Journals (Sweden)

    D. Rucinski

    2003-06-01

    Full Text Available Neutral interstellar helium atoms penetrate into the solar system almost unaffected by gas–plasma interactions in the heliospheric interface region, and thus can be considered as carriers of original information on the basic parameters (like density, temperature, bulk velocity of the Very Local Interstellar Medium (VLISM. Such information can nowadays be derived from analysis of data obtained from different experimental methods: in situ measurements of He atoms (Ulysses, observations of the solar backscattered He 584 A radiation (EUVE, in situ measurements of He + pickup ions (AMPTE, Ulysses, Wind, SOHO, ACE. In view of the current coordinated international ISSI campaign devoted to the study of the helium focusing cone structure and its evolution, we analyze expected variations of neutral He density, of He + pickup fluxes and of their phase space distributions at various phases of the solar activity cycle based on a realistic time-dependent modelling of the neutral helium and He + pickup ion distributions, which reflect solar cycle-induced variations of the photoionization rate. We show that the neutral helium density values are generally anticorrelated with the solar activity phase and in extreme cases (near the downwind axis the maximum-to-minimum density ratio may even exceed factors of ~ 3 at 1 AU. We also demonstrate that in the upwind hemisphere (at 1 AU and beyond the He + fluxes are correlated with the solar cycle activity, whereas on the downwind side the maximum of the expected flux up to distances of ~ 3 AU occurs around solar minimum epoch, and only further away does the correlation with solar activity become positive. Finally, we present the response of the phase space distribution spectra of He + pickup ions (in the solar wind frame for different epochs of the solar cycle and heliocentric distances from 1 to 5 AU covering the range of Ulysses, Wind and ACE observations.Key words. Solar physics, astrophysics and astronomy

  10. Determination of interstellar pickup ion distributions in the solar wind with SOHO and Cluster

    Directory of Open Access Journals (Sweden)

    E. Möbius

    1996-05-01

    Full Text Available Over the last 10 years, the experimental basis for the study of the local interstellar medium has been substantially enhanced by the direct detection of interstellar pickup ions and of interstellar neutral helium within the heliosphere. Pickup ions can be studied for a wide range of interstellar species. However, currently the accuracy of the method to determine the parameters of the interstellar medium, namely neutral density, temperature and relative velocity, is hampered by two problems: (1 In most cases the crucial ionization rates are not available from simultaneous measurements and (2 the transport of the pickup ions in the interplanetary medium substantially modifies the measured spatial distribution of the ions. In this study we will discuss how the enhanced capabilities of the instrumentation on SOHO and Cluster in combination with ongoing efforts to model the pickup ion distributions will lead to a significant improvement over the coming years.

  11. INTERSTELLAR PICKUP ION PRODUCTION IN THE GLOBAL HELIOSPHERE AND HELIOSHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Florinski, V.; Guo, X., E-mail: yw0009@uah.edu [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35805 (United States)

    2016-11-20

    Interstellar pickup ions (PUIs) play a significant part in mediating the solar wind (SW) interaction with the interstellar medium. In this paper, we examine the details of spatial variation of the PUI velocity distribution function (VDF) in the SW by solving the PUI transport equation. We assume the PUI distribution is isotropic resulting from strong pitch-angle scattering by wave–particle interaction. A three-dimensional model combining the MHD treatment of the background SW and neutrals with a kinetic treatment of PUIs throughout the heliosphere and the surrounding local interstellar medium has been developed. The model generates PUI power-law tails via second-order Fermi process. We analyze how PUIs transform across the heliospheric termination shock and obtain the PUI phase space distribution in the inner heliosheath including continuing velocity diffusion. Our simulated PUI spectra are compared with observations made by New Horizons , Ulysses , Voyager 1, 2 , and Cassini , and a satisfactory agreement is demonstrated. Some specific features in the observations, for example, a cutoff of PUI VDF at v = V {sub SW} and a f ∝ v {sup -5} tail in the reference frame of the SW, are well represented by the model.

  12. Probing the Martian Exosphere and Neutral Escape Using Pickup Ions Measured by MAVEN

    Science.gov (United States)

    Rahmati, A.; Larson, D. E.; Cravens, T.; Halekas, J. S.; Lillis, R. J.; McFadden, J. P.; Mitchell, D. L.; Thiemann, E.; Connerney, J. E. P.; Dunn, P.; DiBraccio, G. A.; Espley, J. R.; Eparvier, F. G.; Jakosky, B. M.

    2016-12-01

    Soon after the MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft started orbiting Mars in September 2014, the SEP (Solar Energetic Particle), SWIA (Solar Wind Ion Analyzer), and STATIC (Supra-Thermal and Thermal Ion Composition) instruments onboard the spacecraft started detecting planetary pickup ions. SEP can measure energetic (>50 keV) oxygen pickup ions, the source of which is the extended hot oxygen exosphere of Mars. Model results show that these pickup ions originate from tens of Martian radii upstream of Mars and are energized by the solar wind motional electric field as they gyrate back towards Mars. SEP is blind to pickup hydrogen, as the low energy threshold for detection of hydrogen in SEP is 20 keV; well above the maximum pickup hydrogen energy, which is four times the solar wind proton energy. SWIA and STATIC, on the other hand, can detect both pickup oxygen and pickup hydrogen with energies below 30 keV and created closer to Mars. During the times when MAVEN is outside the Martian bow shock and in the upstream undisturbed solar wind, the solar wind velocity measured by SWIA and the solar wind (or interplanetary) magnetic field measured by the MAG (magnetometer) instrument can be used to model pickup oxygen and hydrogen fluxes near Mars. Solar wind flux measurements of the SWIA instrument are used in calculating charge-exchange frequencies, and data from the EUVM (Extreme Ultraviolet Monitor) and SWEA (Solar Wind Electron Analyzer) instruments are also used in calculating photo-ionization and electron impact frequencies of neutral species in the Martian exosphere. By comparing SEP, SWIA, and STATIC measured pickup ion fluxes with model results, the Martian thermal hydrogen and hot oxygen neutral densities can be probed outside the bow shock, which would place constraints on estimates of oxygen and hydrogen neutral escape rates. We will present model-data comparisons of pickup ions measured outside the Martian bow shock. Our analysis reveals an

  13. Revisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2007-01-01

    Full Text Available We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear or nonlinear energy diffusion (Fermi-2 acceleration induced by counterflowing ambient waves. In the up-to-now literature connected with the convection of pick-up ions by the solar wind only adiabatic cooling of these ions is considered which in the solar wind frame takes care of filling the gap between the injection energy and energies of the thermal bulk of solar wind ions. Here we reinvestigate the basics of the theory behind this assumption of adiabatic pick-up ion reactions and correlated predictions derived from it. We then compare it with the new assumption of a pure magnetic cooling of pick-up ions simply resulting from their being convected in an interplanetary magnetic field which decreases in magnitude with increase of solar distance. We compare the results for pick-up ion distribution functions derived along both ways and can point out essential differences of observational and diagnostic relevance. Furthermore we then include stochastic acceleration processes by wave-particle interactions. As we can show, magnetic cooling in conjunction with diffusive acceleration by wave-particle interaction allows for an unbroken power law with the unique power index γ=−5 beginning from lowest velocities up to highest energy particles of about 100 KeV which just marginally can be in resonance with magnetoacoustic turbulences. Consequences for the resulting pick-up ion pressures are also analysed.

  14. Revisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2008-01-01

    Full Text Available We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear or nonlinear energy diffusion (Fermi-2 acceleration induced by counterflowing ambient waves. In the up-to-now literature connected with the convection of pick-up ions by the solar wind only adiabatic cooling of these ions is considered which in the solar wind frame takes care of filling the gap between the injection energy and energies of the thermal bulk of solar wind ions. Here we reinvestigate the basics of the theory behind this assumption of adiabatic pick-up ion reactions and correlated predictions derived from it. We then compare it with the new assumption of a pure magnetic cooling of pick-up ions simply resulting from their being convected in an interplanetary magnetic field which decreases in magnitude with increase of solar distance. We compare the results for pick-up ion distribution functions derived along both ways and can point out essential differences of observational and diagnostic relevance. Furthermore we then include stochastic acceleration processes by wave-particle interactions. As we can show, magnetic cooling in conjunction with diffusive acceleration by wave-particle interaction allows for an unbroken power law with the unique power index γ=−5 beginning from lowest velocities up to highest energy particles of about 100 KeV which just marginally can be in resonance with magnetoacoustic turbulences. Consequences for the resulting pick-up ion pressures are also analysed.

  15. Oxygen Pickup Ions Measured by MAVEN Outside the Martian Bow Shock

    Science.gov (United States)

    Rahmati, A.; Cravens, T.; Larson, D. E.; Lillis, R. J.; Dunn, P.; Halekas, J. S.; Connerney, J. E. P.; Eparvier, F. G.; Thiemann, E.; Mitchell, D. L.; Jakosky, B. M.

    2015-12-01

    The MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft entered orbit around Mars on September 21, 2014 and has since been detecting energetic oxygen pickup ions by its SEP (Solar Energetic Particles) and SWIA (Solar Wind Ion Analyzer) instruments. The oxygen pickup ions detected outside the Martian bowshock and in the upstream solar wind are associated with the extended hot oxygen exosphere of Mars, which is created mainly by the dissociative recombination of molecular oxygen ions with electrons in the ionosphere. We use analytic solutions to the equations of motion of pickup ions moving in the undisturbed upstream solar wind magnetic and motional electric fields and calculate the flux of oxygen pickup ions at the location of MAVEN. Our model calculates the ionization rate of oxygen atoms in the exosphere based on the hot oxygen densities predicted by Rahmati et al. (2014), and the sources of ionization include photo-ionization, charge exchange, and electron impact ionization. The photo-ionization frequency is calculated using the FISM (Flare Irradiance Spectral Model) solar flux model, based on MAVEN EUVM (Extreme Ultra-Violet Monitor) measurements. The frequency of charge exchange between a solar wind proton and an oxygen atom is calculated using MAVEN SWIA solar wind proton flux measurements, and the electron impact ionization frequency is calculated based on MAVEN SWEA (Solar Wind Electron Analyzer) solar wind electron flux measurements. The solar wind magnetic field used in the model is from the measurements taken by MAVEN MAG (magnetometer) in the upstream solar wind. The good agreement between our predicted pickup oxygen fluxes and the MAVEN SEP and SWIA measured ones confirms detection of oxygen pickup ions and these model-data comparisons can be used to constrain models of hot oxygen densities and photochemical escape flux.

  16. Survey of pickup ion signatures in the vicinity of Titan using CAPS/IMS

    Science.gov (United States)

    Regoli, L. H.; Coates, A. J.; Thomsen, M. F.; Jones, G. H.; Roussos, E.; Waite, J. H.; Krupp, N.; Cox, G.

    2016-09-01

    Pickup ion detection at Titan is challenging because ion cyclotron waves are rarely detected in the vicinity of the moon. In this work, signatures left by freshly produced pickup heavy ions (m/q ˜ 16 to m/q ˜ 28) as detected in the plasma data by the Cassini Plasma Spectrometer/Ion Mass Spectrometer (CAPS/IMS) instrument on board Cassini are analyzed. In order to discern whether these correspond to ions of exospheric origin, one of the flybys during which the reported signatures were observed is investigated in detail. For this purpose, ion composition data from time-of-flight measurements and test particle simulations to constrain the ions' origin are used. After being validated, the detection method is applied to all the flybys for which the CAPS/IMS instrument gathered valid data, constraining the region around the moon where the signatures are observed. The results reveal an escape region located in the anti-Saturn direction as expected from the nominal corotation electric field direction. These findings provide new constraints for the area of freshly produced pickup ion escape, giving an approximate escape rate of 3.3-2+3×1023 ions· s-1.

  17. Sodium Pick-Up Ion Observations in the Solar Wind Upstream of Mercury

    Science.gov (United States)

    Jasinski, J. M.; Raines, J. M.; Slavin, J. A.; Regoli, L. R.; Murphy, N.

    2018-05-01

    We present the first observations of sodium pick-up ions upstream of Mercury’s magnetosphere. From these observations we infer properties of Mercury’s sodium exosphere and implications for the solar wind interaction with Mercury’s magnetosphere.

  18. Pickup Ions in the Plasma Environments of Mars, Comets, and Enceladus

    Science.gov (United States)

    Cravens, T.; Rahmati, A.; Sakai, S.; Madanian, H.; Larson, D. E.; Lillis, R. J.; Halekas, J. S.; Goldstein, R.; Burch, J. L.; Clark, G. B.; Jakosky, B. M.

    2015-12-01

    Ions created within a flowing plasma by ionization of neutrals respond to the electric and magnetic fields associated with the flow becoming what are called pick-up ions (PUI). PUI play an important role in many solar system plasma environments and affect the energy and momentum balance of the plasma flow. PUI have been observed during several recent space missions and PUI data will be compared and interpreted using models. Pick-up oxygen ions were observed in the solar wind upstream of Mars by the Solar Energetic Particle (SEP) and Solar Wind Ion Analyzer (SWIA) instruments on NASA's MAVEN (Mars Atmosphere and Volatile EvolutioN) spacecraft. The pick-up oxygen ions are created when atoms in the hot corona are ionized by solar radiation and charge exchange with solar wind protons. The ion fluxes measured by SEP can constrain the oxygen escape rate from Mars. PUI were also been detected at distances of 10 - 100 km from the nucleus of comet 67P/Churyumov- Gerasimenko (67P/CG) by plasma instruments (IES and ICA) onboard the Rosetta Orbiter when the comet was at 3 AU. The newly-born cometary ions are accelerated by the solar wind motional electric field but remain un-magnetized, as suggested by pre-encounter models (Rubin et al., 2014). The inner magnetosphere of Saturn and the water plume of the icy satellite Enceladus provide a third example of PUI. H2O+ ions created by ionization of neutral water producing ions that are picked-up by the co-rotating magnetospheric plasma flow. These ions then undergo a complex interaction with the plume gas including collisions that convert most H2O+ ions to H3O+, as measured by the Ion and Neutral Mass Spectrometer (INMS) onboard the Cassini spacecraft.

  19. Comparative pick-up ion distributions at Mars and Venus: Consequences for atmospheric deposition and escape

    Science.gov (United States)

    Curry, Shannon M.; Luhmann, Janet; Ma, Yingjuan; Liemohn, Michael; Dong, Chuanfei; Hara, Takuya

    2015-09-01

    Without the shielding of a substantial intrinsic dipole magnetic field, the atmospheres of Mars and Venus are particularly susceptible to similar atmospheric ion energization and scavenging processes. However, each planet has different attributes and external conditions controlling its high altitude planetary ion spatial and energy distributions. This paper describes analogous test particle simulations in background MHD fields that allow us to compare the properties and fates, precipitation or escape, of the mainly O+ atmospheric pick-up ions at Mars and Venus. The goal is to illustrate how atmospheric and planetary scales affect the upper atmospheres and space environments of our terrestrial planet neighbors. The results show the expected convection electric field-related hemispheric asymmetries in both precipitation and escape, where the degree of asymmetry at each planet is determined by the planetary scale and local interplanetary field strength. At Venus, the kinetic treatment of O+ reveals a strong nightside source of precipitation while Mars' crustal fields complicate the simple asymmetry in ion precipitation and drive a dayside source of precipitation. The pickup O+ escape pattern at both Venus and Mars exhibits low energy tailward escape, but Mars exhibits a prominent, high energy 'polar plume' feature in the hemisphere of the upward convection electric field while the Venus ion wake shows only a modest poleward concentration. The overall escape is larger at Venus than Mars (2.1 ×1025 and 4.3 ×1024 at solar maximum, respectively), but the efficiency (likelihood) of O+ escaping is 2-3 times higher at Mars. The consequences of these comparisons for pickup ion related atmospheric energy deposition, loss rates, and detection on spacecraft including PVO, VEX, MEX and MAVEN are considered. In particular, both O+ precipitation and escape show electric field controlled asymmetries that grow with energy, while the O+ fluxes and energy spectra at selected spatial

  20. VOYAGER OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS: 2–6 au

    International Nuclear Information System (INIS)

    Aggarwal, Poornima; Taylor, David K.; Smith, Charles W.; Joyce, Colin J.; Fisher, Meghan K.; Isenberg, Philip A.; Vasquez, Bernard J.; Schwadron, Nathan A.; Cannon, Bradford E.; Richardson, John D.

    2016-01-01

    We report observations by the Voyager 1 and 2 spacecraft of low-frequency magnetic waves excited by newborn interstellar pickup ions H + and He + during 1978–1979 when the spacecraft were in the range from 2 to 6.3 au. The waves have the expected association with the cyclotron frequency of the source ions, are left-hand polarized in the spacecraft frame, and have minimum variance directions that are quasi-parallel to the local mean magnetic field. There is one exception to this in that one wave event that is excited by pickup H + is right-hand polarized in the spacecraft frame, but similar exceptions have been reported by Cannon et al. and remain unexplained. We apply the theory of Lee and Ip that predicts the energy spectrum of the waves and then compare growth rates with turbulent cascade rates under the assumption that turbulence acts to destroy the enhanced wave activity and transport the associated energy to smaller scales where dissipation heats the background plasma. As with Cannon et al., we find that the ability to observe the waves depends on the ambient turbulence being weak when compared with growth rates, thereby allowing sustained wave growth. This analysis implies that the coupled processes of pitch-angle scattering and wave generation are continuously associated with newly ionized pickup ions, despite the fact that the waves themselves may not be directly observable. When waves are not observed, but wave excitation can be argued to be present, the wave energy is simply absorbed by the turbulence at a rate that prevents significant accumulation. In this way, the kinetic process of wave excitation by scattering of newborn ions continues to heat the plasma without producing observable wave energy. These findings support theoretical models that invoke efficient scattering of new pickup ions, leading to turbulent driving in the outer solar wind and in the IBEX ribbon beyond the heliopause.

  1. VOYAGER OBSERVATIONS OF MAGNETIC WAVES DUE TO NEWBORN INTERSTELLAR PICKUP IONS: 2–6 au

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Poornima [Electrical Engineering Department, Cooper Union, New York, NY 10003 (United States); Taylor, David K. [Rensselaer Polytechnic Institute, Troy, NH 12180 (United States); Smith, Charles W.; Joyce, Colin J.; Fisher, Meghan K.; Isenberg, Philip A.; Vasquez, Bernard J.; Schwadron, Nathan A. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 (United States); Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, FL 32306 (United States); Richardson, John D., E-mail: neema2000@gmail.com, E-mail: daves@orol.org, E-mail: Charles.Smith@unh.edu, E-mail: cjl46@wildcats.unh.edu, E-mail: mkl54@wildcats.unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: N.Schwadron@unh.edu, E-mail: bc13h@my.fsu.edu, E-mail: jdr@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 37-655, Cambridge, MA 02139 (United States)

    2016-05-10

    We report observations by the Voyager 1 and 2 spacecraft of low-frequency magnetic waves excited by newborn interstellar pickup ions H{sup +} and He{sup +} during 1978–1979 when the spacecraft were in the range from 2 to 6.3 au. The waves have the expected association with the cyclotron frequency of the source ions, are left-hand polarized in the spacecraft frame, and have minimum variance directions that are quasi-parallel to the local mean magnetic field. There is one exception to this in that one wave event that is excited by pickup H{sup +} is right-hand polarized in the spacecraft frame, but similar exceptions have been reported by Cannon et al. and remain unexplained. We apply the theory of Lee and Ip that predicts the energy spectrum of the waves and then compare growth rates with turbulent cascade rates under the assumption that turbulence acts to destroy the enhanced wave activity and transport the associated energy to smaller scales where dissipation heats the background plasma. As with Cannon et al., we find that the ability to observe the waves depends on the ambient turbulence being weak when compared with growth rates, thereby allowing sustained wave growth. This analysis implies that the coupled processes of pitch-angle scattering and wave generation are continuously associated with newly ionized pickup ions, despite the fact that the waves themselves may not be directly observable. When waves are not observed, but wave excitation can be argued to be present, the wave energy is simply absorbed by the turbulence at a rate that prevents significant accumulation. In this way, the kinetic process of wave excitation by scattering of newborn ions continues to heat the plasma without producing observable wave energy. These findings support theoretical models that invoke efficient scattering of new pickup ions, leading to turbulent driving in the outer solar wind and in the IBEX ribbon beyond the heliopause.

  2. Interaction of intersteller pick-up ions with the solar wind

    International Nuclear Information System (INIS)

    Mobius, E.; Klecker, B.; Hovestadt, D.; Scholer, M.

    1988-01-01

    The interaction of interstellar pick-up ions with the solar wind is studied by comparing a model for the velocity distribution function of pick-up ions with actual measurements of He + ions in the solar wind. The model includes the effects of pitch-angle diffusion due to interplanetary Alfven waves, adiabatic deceleration in the expanding solar wind and the radial variation of the source function. It is demonstrated that the scattering mean free path is in the range ≤0.1 AU and that energy diffusion can be neglected as compared with adiabatic deceleration. The effects of adiabatic focusing, of the radial variation of the neutral density and of an variation of the solar wind velocity with distance from the Sun are investigated. With the correct choice of these parameters the authors can model the measured energy spectra of the pick-up ions does not vary with the solar wind velocity and the direction of the interplanetary magnetic field for a given local neutral gas density and ionization rate. Therefore, the comparison of the model distributions with the measurements leads to a quantitative determination of the local interstellar gas density

  3. A MEASUREMENT OF THE ADIABATIC COOLING INDEX FOR INTERSTELLAR HELIUM PICKUP IONS IN THE INNER HELIOSPHERE

    International Nuclear Information System (INIS)

    Saul, Lukas; Wurz, Peter; Kallenbach, Reinald

    2009-01-01

    Interstellar neutral gas enters the inner heliosphere where it is ionized and becomes the pickup ion population of the solar wind. It is often assumed that this population will subsequently cool adiabatically, like an expanding ideal gas due, to the divergent flow of the solar wind. Here, we report the first independent measure of the effective adiabatic cooling index in the inner heliosphere from SOHO CELIAS measurements of singly charged helium taken during times of perpendicular interplanetary magnetic field. We use a simple adiabatic transport model of interstellar pickup helium ions, valid for the upwind region of the inner heliosphere. The time averaged velocity spectrum of helium pickup ions measured by CELIAS/CTOF is fit to this model with a single free parameter which indicates an effective cooling rate with a power-law index of γ = 1.35 ± 0.2. While this average is consistent with the 'ideal-gas' assumption of γ = 1.5, the analysis indicates that such an assumption will not apply in general, and that due to observational constraints further measurements are necessary to constrain the cooling process. Implications are discussed for understanding the transport processes in the inner heliosphere and improving this measurement technique.

  4. Modeling and Observation of Interstellar He+ Pickup Ions in the Inner Heliosphere

    Science.gov (United States)

    Chen, Junhong

    Interstellar pickup ions constitute a charged particle population that originates from interstellar neutrals inside the heliosphere. They are produced by photoionization, charge exchange with solar wind ions, and electron impact ionization (EI). Once ionized, they are picked up by the interplanetary magnetic field (IMF) and rapidly swept outward with the solar wind. Typically, pickup ion distributions have been described in terms of a velocity distribution function that evolves through fast pitch angle scattering followed by adiabatic cooling during radial transport in the reference frame of the solar wind [e.g., Vasyliunas & Siscoe, 1976, VS76 hereafter]. In the VS76 model, the slope of the isotropic velocity distributions is controlled by the combination of the ionization rate and the cooling process. Thus far, for the cooling index that relates the slope of the velocity distribution to the radial transport and expansion of the pickup ions a constant value of 3/2 has been widely used. The implicit assumptions to arrive at this value are immediate PUI isotropization due to pitch angle scattering and solar wind expansion with the square of the distance from the Sun. Any experimental determination of the cooling index depends on the knowledge of the ionization rate and its spatial variation, as well as solar wind and interplanetary conditions. In this thesis, we study their influences on the PUI cooling index and separate them by making use of the two complementary helium PUI data sets from SWICS instrument on the ACE spacecraft, and PLASTIC instrument on STEREO spacecraft. We use the pickup ion observations from ACE SIWCS in the last solar cycle to determine the cooling index, and the possible effects of the electron impact ionization on the determination of the cooling index. With pickup ion observations from STEREO PLASTIC, we determine how solar wind expansion patterns affect the cooling index. We find that the cooling index varies substantially with solar

  5. Seasonal variation of Martian pick-up ions: Evidence of breathing exosphere

    Science.gov (United States)

    Yamauchi, M.; Hara, T.; Lundin, R.; Dubinin, E.; Fedorov, A.; Sauvaud, J.-A.; Frahm, R. A.; Ramstad, R.; Futaana, Y.; Holmstrom, M.; Barabash, S.

    2015-12-01

    The Mars Express (MEX) Ion Mass Analyser (IMA) found that the detection rate of the ring-like distribution of protons in the solar wind outside of the bow shock to be quite different between Mars orbital summer (around perihelion) and orbital winter (around aphelion) for four Martian years, while the north-south asymmetry is much smaller than the perihelion-aphelion difference. Further analyses using eight years of MEX/IMA solar wind data between 2005 and 2012 has revealed that the detection frequency of the pick-up ions originating from newly ionized exospheric hydrogen with certain flux strongly correlates with the Sun-Mars distance, which changes approximately every two years. Variation due to the solar cycle phase is not distinguishable partly because this effect is masked by the seasonal variation under the MEX capability of plasma measurements. This finding indicates that the variation in solar UV has a major effect on the formation of the pick-up ions, but this is not the only controlling factor.

  6. Comet 73P Measurements of Solar Wind Interactions, Cometary Ion Pickup, and Spatial Distribution

    Science.gov (United States)

    Gilbert, J. A.; Lepri, S. T.; Rubin, M.; Combi, M. R.; Zurbuchen, T.

    2015-12-01

    Several fragments of Comet 73P/Schwassmann-Wachmann 3 passed near the Earth following a 2006 disintegration episode. Unique measurements regarding the charge state composition and the elemental abundances of both cometary and heliospheric plasma were made during this time by both the ACE/SWICS and Wind/STICS sensors. As the solar wind passed through the neutral cometary coma, it experienced charge exchange that was observed as an increase in the ratio of He+/He++. In addition, particles originating from fragments trailing the major cometary objects were ionized and picked up by the solar wind. The cometary material can be identified by the concentrations of water-group pickup ions having a mass-per-charge ratio of 16-18 amu/e, indicating that these are actively sublimating fragments. Here we present an analysis of cometary composition, spatial distribution, directionality, and heliospheric interactions with a focus on Helium, Carbon (C/O), and water-group ions.

  7. Challenges in the determination of the interstellar flow longitude from the pickup ion cutoff

    Science.gov (United States)

    Taut, A.; Berger, L.; Möbius, E.; Drews, C.; Heidrich-Meisner, V.; Keilbach, D.; Lee, M. A.; Wimmer-Schweingruber, R. F.

    2018-03-01

    Context. The interstellar flow longitude corresponds to the Sun's direction of movement relative to the local interstellar medium. Thus, it constitutes a fundamental parameter for our understanding of the heliosphere and, in particular, its interaction with its surroundings, which is currently investigated by the Interstellar Boundary EXplorer (IBEX). One possibility to derive this parameter is based on pickup ions (PUIs) that are former neutral ions that have been ionized in the inner heliosphere. The neutrals enter the heliosphere as an interstellar wind from the direction of the Sun's movement against the partially ionized interstellar medium. PUIs carry information about the spatial variation of their neutral parent population (density and flow vector field) in their velocity distribution function. From the symmetry of the longitudinal flow velocity distribution, the interstellar flow longitude can be derived. Aim. The aim of this paper is to identify and eliminate systematic errors that are connected to this approach of measuring the interstellar flow longitude; we want to minimize any systematic influences on the result of this analysis and give a reasonable estimate for the uncertainty. Methods: We use He+ data measured by the PLAsma and SupraThermal Ion Composition (PLASTIC) sensor on the Solar TErrestrial RElations Observatory Ahead (STEREO A) spacecraft. We analyze a recent approach, identify sources of systematic errors, and propose solutions to eliminate them. Furthermore, a method is introduced to estimate the error associated with this approach. Additionally, we investigate how the selection of interplanetary magnetic field angles, which is closely connected to the pickup ion velocity distribution function, affects the result for the interstellar flow longitude. Results: We find that the revised analysis used to address part of the expected systematic effects obtains significantly different results than presented in the previous study. In particular

  8. On the Stability of Pick-up Ion Ring Distributions in the Outer Heliosheath

    Science.gov (United States)

    Summerlin, Errol J.; Viñas, Adolfo F.; Moore, Thomas E.; Christian, Eric R.; Cooper, John F.

    2014-10-01

    The "secondary energetic neutral atom (ENA)" hypothesis for the ribbon feature observed by the Interstellar Boundary Explorer (IBEX) posits that the neutral component of the solar wind continues beyond the heliopause and charge exchanges with interstellar ions in the Outer Heliosheath (OHS). This creates pick-up ions that gyrate about the draped interstellar magnetic field (ISMF) lines at pitch angles near 90° on the locus where the ISMF lies tangential to the heliopause and perpendicular to the heliocentric radial direction. This location closely coincides with the location of the ribbon feature according to the prevailing inferences of the ISMF orientation and draping. The locally gyrating ions undergo additional charge exchange and escape as free-flying neutral atoms, many of which travel back toward the inner solar system and are imaged by IBEX as a ribbon tracing out the locus described above. For this mechanism to succeed, the pick-up ions must diffuse in pitch angle slowly enough to permit secondary charge exchange before their pitch angle distribution substantially broadens away from 90°. Previous work using linear Vlasov dispersion analysis of parallel propagating waves has suggested that the ring distribution in the OHS is highly unstable, which, if true, would make the secondary ENA hypothesis incapable of rendering the observed ribbon. In this paper, we extend this earlier work to more realistic ring distribution functions. We find that, at the low densities necessary to produce the observed IBEX ribbon via the secondary ENA hypothesis, growth rates are highly sensitive to the temperature of the beam and that even very modest temperatures of the ring beam corresponding to beam widths of distributions necessary to produce the observed IBEX ENA flux via the secondary ENA hypothesis will be unstable to their own self-generated turbulence.

  9. Modelling of interplanetary pickup ion fluxes and relevance for LISM parameters

    International Nuclear Information System (INIS)

    Fahr, H.J.; Rucinski, D.

    1989-01-01

    It has been known for many years that neutral interstellar atoms enter the solar system from the upwind side and penetrate deep into the inner heliosphere. Helium atoms, in particular, advance towards very small solar distances before they are ionized and then again convected as He - pickup ions outwards with the solar wind. Since these ions were recently detected in space, we concentrate here on calculations of He + production rates and He + fluxes. It is shown that inside 1 a.u., the He - production is essentially determined both by solar e.u.v. photoionization and by electron impact ionization. We calculate He + production rates as a function of space coordinates, taking into account the core-halo structure of the energy distribution of solar wind electrons and their temperature distribution with distance according to relevant solar wind models. For this purpose, a newly developed program to compute He densities was used. In contrast to the production of H + , the He - production rates are found to be higher on the downwind axis than on the upwind axis by a factor of 5. We also determine partial and total He + ion fluxes as a function of solar distance and longitude. It is interesting to note that only the values for total fluxes agree well with the integrated He + fluxes measured by the SULEICA experiment aboard the AMPTE satellite. This indicates that pickup ions under the influence of the intrinsic MHD wave turbulence in the solar wind change their primary seed distribution function by rapid pitch-angle scattering and subsequent adiabatic cooling. To interpret the He + intensity profile along the orbit of the Earth in terms of LISM helium parameters, we point to the need to take into account carefully electron impact ionization in order to prevent misinterpretations. (author)

  10. Heliospheric pick-up ions influencing thermodynamics and dynamics of the distant solar wind

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2002-01-01

    Full Text Available Neutral interstellar H-atoms penetrate into the inner heliosphere and upon the event of ionization are converted into pick-up ions (PUIs. The magnetized solar wind flow incorporates these ions into the plasma bulk and enforces their co-motion. By nonlinear interactions with wind-entrained Alfvén waves, these ions are then processed in the comoving velocity space. The complete pick-up process is connected with forces acting back to the original solar wind ion flow, thereby decelerating and heating the solar wind plasma. As we show here, the resulting deceleration cannot be treated as a pure loading effect, but requires adequate consideration of the action of the pressure of PUI-scattered waves operating by the PUI pressure gradient. Hereby, it is important to take into proper account the stochastic acceleration which PUIs suffer from at their convection out of the inner heliosphere by quasi-linear interactions with MHD turbulences. Only then can the presently reported VOYAGER observations of solar wind decelerations and heatings in the outer heliosphere be understood in view of the most likely values of interstellar gas parameters, such as an H-atom density of 0.12 cm-3 . Solar wind protons (SWPs appear to be globally heated in their motion to larger solar distances. Ascribing the needed heat transfer to the action of suprathermal PUIs, which drive MHD waves that are partly absorbed by SWPs, in order to establish the observed SWP polytropy, we can obtain a quantitative expression for the solar wind proton pressure as a function of solar distance. This expression clearly shows the change from an adiabatic to a quasi-polytropic SWP behaviour with a decreasing polytropic index at increasing distances. This also allows one to calculate the average percentage of initial pick-up energy fed into the thermal proton energy. In a first order evaluation of this expression, we can estimate that about 10% of the initial PUI injection energy is eventually

  11. Dayside pickup oxygen ion precipitation at Venus and Mars: Spatial distributions, energy deposition and consequences

    International Nuclear Information System (INIS)

    Luhmann, J.G.; Kozyra, J.U.

    1991-01-01

    The fluxes and energy spectra of picked-up planetary O + ions incident on the dayside atmospheres of Venus and Mars are calculated using the neutral exposure models of Nagy and Cravens (1988) and the Spreiter and Stahara (1980) gasdynamic model of the magnetosheath electric and magnetic field. Cold (∼10 eV) O + ions are launched from hemispherical grids of starting points covering the daysides of the planets and their trajectories are followed until they either impact the dayside obstacle or cross the terminator plane. The impacting, or precipitating, ion fluxes are weighted according to the altitude of the hemispherical starting point grid in a manner consistent with the exosphere density models and the local photoion production rate. Maps of precipitating ion number flux and energy flux show the asymmetrical distribution of dayside energy deposition expected from this source which is unique to the weakly magnetized planets. Although the associated heating of the atmosphere and ionsphere is found to be negligible compared to that from the usual sources, backscattered or sputtered neutral oxygen atoms are produced at energies exceeding that needed for escape from the gravitational fields of both planets. These neutral winds, driven by pickup ion precipitation, represent a possibly significant loss of atmospheric constituents over the age of the solar system

  12. Determining the Interstellar Wind Longitudinal Inflow Evolution Using Pickup Ions in the Helium Focusing Cone

    Science.gov (United States)

    Spitzer, S. A.; Gilbert, J. A.; Lepri, S. T.

    2017-12-01

    We propose to determine the longitudinal inflow direction of the local interstellar medium through the Heliosphere. This longitudinal inflow direction directly correlates to the longitudinal direction of the helium focusing cone with respect to the Sun. We can calculate this direction by finding the He+ pickup ion density peak as mass spectrometers such as ACE/SWICS, Wind/STICS, and Helios/Micrometeoroid Detector and Analyzer pass through the focusing cone. Mapping from the location of this density peak to the Sun, around which the helium is focused, will directly yield the desired longitudinal direction. We will find this direction for each year since the first measurements in the 1970s through the present and thereby analyze its evolution over time. This poster outlines our proposed method and initial results.

  13. On the stability of pick-up ion ring distributions in the outer heliosheath

    International Nuclear Information System (INIS)

    Summerlin, Errol J.; Viñas, Adolfo F.; Moore, Thomas E.; Christian, Eric R.; Cooper, John F.

    2014-01-01

    The 'secondary energetic neutral atom (ENA)' hypothesis for the ribbon feature observed by the Interstellar Boundary Explorer (IBEX) posits that the neutral component of the solar wind continues beyond the heliopause and charge exchanges with interstellar ions in the Outer Heliosheath (OHS). This creates pick-up ions that gyrate about the draped interstellar magnetic field (ISMF) lines at pitch angles near 90° on the locus where the ISMF lies tangential to the heliopause and perpendicular to the heliocentric radial direction. This location closely coincides with the location of the ribbon feature according to the prevailing inferences of the ISMF orientation and draping. The locally gyrating ions undergo additional charge exchange and escape as free-flying neutral atoms, many of which travel back toward the inner solar system and are imaged by IBEX as a ribbon tracing out the locus described above. For this mechanism to succeed, the pick-up ions must diffuse in pitch angle slowly enough to permit secondary charge exchange before their pitch angle distribution substantially broadens away from 90°. Previous work using linear Vlasov dispersion analysis of parallel propagating waves has suggested that the ring distribution in the OHS is highly unstable, which, if true, would make the secondary ENA hypothesis incapable of rendering the observed ribbon. In this paper, we extend this earlier work to more realistic ring distribution functions. We find that, at the low densities necessary to produce the observed IBEX ribbon via the secondary ENA hypothesis, growth rates are highly sensitive to the temperature of the beam and that even very modest temperatures of the ring beam corresponding to beam widths of <1° are sufficient to damp the self-generated waves associated with the ring beam. Thus, at least from the perspective of linear Vlasov dispersion analysis of parallel propagating waves, there is no reason to expect that the ring distributions necessary to

  14. INTERSTELLAR PICK-UP IONS OBSERVED BETWEEN 11 AND 22 AU BY NEW HORIZONS

    International Nuclear Information System (INIS)

    Randol, B. M.; McComas, D. J.; Schwadron, N. A.

    2013-01-01

    We report new observations by the Solar Wind Around Pluto instrument on the New Horizons spacecraft, which measures energy per charge (E/q) spectra of solar wind and interstellar pick-up ions (PUIs) between 11 AU and 22 AU from the Sun. The data provide an unprecedented look at PUIs as there have been very few measurements of PUIs beyond 10 AU. We analyzed the PUI part of the spectra by comparing them to the classic Vasyliunas and Siscoe PUI model. Our analysis indicates that PUIs are usually well-described by this distribution. We derive parameters relevant to PUI studies, such as the ionization rate normalized to 1 AU. Our result for the average ionization rate between 11 and 12 AU agrees with an independently derived average value found during the same time. Later, we find a general increase in the ionization rate, which is consistent with the increase in solar activity. We also calculate the PUI thermal pressure, which appears to be roughly consistent with previous results. Through fitting of the solar wind proton peaks in our spectra, we derive solar wind thermal pressures. Based on our analysis, we predict a ratio of PUI thermal pressure to solar wind thermal pressure just inside the termination shock to be between 100 and >1000.

  15. A Data-driven Model of the Solar Wind, Interstellar Pickup Ions, and Turbulence Throughout the Interplanetary Space

    Science.gov (United States)

    Kim, T. K.; Kryukov, I.; Pogorelov, N. V.; Elliott, H. A.; Zank, G. P.

    2017-12-01

    The outer heliosphere is an interesting region characterized by the interaction between the solar wind and the interstellar neutral atoms. Having accomplished the mission to Pluto in 2015 and currently on the way to the Kuiper Belt, the New Horizons spacecraft is following the footsteps of the two Voyager spacecraft that previously explored this region lying roughly beyond 30 AU from the Sun. We model the three-dimensional, time-dependent solar wind plasma flow to the outer heliosphere using our own software Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS), which, in addition to the thermal solar wind plasma, takes into account charge exchange of the solar wind protons with interstellar neutral atoms and treats nonthermal ions (i.e., pickup ions) born during this process as a separate fluid. Additionally, MS-FLUKSS allows us to model turbulence generated by pickup ions. We use MS-FLUKSS to investigate the evolution of plasma and turbulent fluctuations along the trajectory of the New Horizons spacecraft using plasma and turbulence parameters from OMNI data as time-dependent boundary conditions at 1 AU for the Reynolds-averaged MHD equations. We compare the model with in situ plasma observations by New Horizons, Voyager 2, and Ulysses. We also compare the model pickup proton parameters with those derived from the Ulysses-SWICS data.

  16. Solar wind heating by an embedded quasi-isothermal pick-up ion fluid

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    Full Text Available It is well known that the solar wind plasma consists of primary ions of solar coronal origin and secondary ions of interstellar origin. Interstellar H-atoms penetrate into the inner heliosphere and when ionized there are converted into secondary ions. These are implanted into the magnetized solar wind flow and are essentially enforced to co-move with this flow. By nonlinear interactions with wind-entrained Alfvén waves the latter are processed in the co-moving velocity space. This pick-up process, however, also causes actions back upon the original solar wind flow, leading to a deceleration, as well as a heating of the solar wind plasma. The resulting deceleration is not only due to the loading effect, but also due to the action of the pressure gradient. To calculate the latter, it is important to take into account the stochastic acceleration that suffers at their convection out of the inner heliosphere by the quasi-linear interactions with MHD turbulences. Only then can the presently reported VOYAGER observations of solar wind decelerations and heatings in the outer heliosphere be understood in terms of the current, most likely values of interstellar gas parameters. In a consistent view of the thermodynamics of the solar wind plasma, which is composed of secondary ions and solar wind protons, we also derive that the latter are globally heated at their motion to larger solar distances. The arising heat transfer is due to the action of suprathermal ions which drive MHD waves that are partially absorbed by solar wind protons and thereby establish their observed quasi-polytropy. We obtain a quantitative expression for the solar wind proton pressure as a function of solar distance. This expression clearly shows the change from an adiabatic to a quasi-polytropic behaviour with a decreasing polytropic index at increasing distances, as has been observed by the VOYAGERS. This also allows one to calculate the average percentage of the intitial energy

  17. Solar wind heating by an embedded quasi-isothermal pick-up ion fluid

    Directory of Open Access Journals (Sweden)

    H. J. Fahr

    2002-10-01

    Full Text Available It is well known that the solar wind plasma consists of primary ions of solar coronal origin and secondary ions of interstellar origin. Interstellar H-atoms penetrate into the inner heliosphere and when ionized there are converted into secondary ions. These are implanted into the magnetized solar wind flow and are essentially enforced to co-move with this flow. By nonlinear interactions with wind-entrained Alfvén waves the latter are processed in the co-moving velocity space. This pick-up process, however, also causes actions back upon the original solar wind flow, leading to a deceleration, as well as a heating of the solar wind plasma. The resulting deceleration is not only due to the loading effect, but also due to the action of the pressure gradient. To calculate the latter, it is important to take into account the stochastic acceleration that suffers at their convection out of the inner heliosphere by the quasi-linear interactions with MHD turbulences. Only then can the presently reported VOYAGER observations of solar wind decelerations and heatings in the outer heliosphere be understood in terms of the current, most likely values of interstellar gas parameters. In a consistent view of the thermodynamics of the solar wind plasma, which is composed of secondary ions and solar wind protons, we also derive that the latter are globally heated at their motion to larger solar distances. The arising heat transfer is due to the action of suprathermal ions which drive MHD waves that are partially absorbed by solar wind protons and thereby establish their observed quasi-polytropy. We obtain a quantitative expression for the solar wind proton pressure as a function of solar distance. This expression clearly shows the change from an adiabatic to a quasi-polytropic behaviour with a decreasing polytropic index at increasing distances, as has been observed by the VOYAGERS. This also allows one to calculate the average percentage of the intitial energy

  18. Investigating Systematic Errors of the Interstellar Flow Longitude Derived from the Pickup Ion Cutoff

    Science.gov (United States)

    Taut, A.; Berger, L.; Drews, C.; Bower, J.; Keilbach, D.; Lee, M. A.; Moebius, E.; Wimmer-Schweingruber, R. F.

    2017-12-01

    Complementary to the direct neutral particle measurements performed by e.g. IBEX, the measurement of PickUp Ions (PUIs) constitutes a diagnostic tool to investigate the local interstellar medium. PUIs are former neutral particles that have been ionized in the inner heliosphere. Subsequently, they are picked up by the solar wind and its frozen-in magnetic field. Due to this process, a characteristic Velocity Distribution Function (VDF) with a sharp cutoff evolves, which carries information about the PUI's injection speed and thus the former neutral particle velocity. The symmetry of the injection speed about the interstellar flow vector is used to derive the interstellar flow longitude from PUI measurements. Using He PUI data obtained by the PLASTIC sensor on STEREO A, we investigate how this concept may be affected by systematic errors. The PUI VDF strongly depends on the orientation of the local interplanetary magnetic field. Recently injected PUIs with speeds just below the cutoff speed typically form a highly anisotropic torus distribution in velocity space, which leads to a longitudinal transport for certain magnetic field orientation. Therefore, we investigate how the selection of magnetic field configurations in the data affects the result for the interstellar flow longitude that we derive from the PUI cutoff. Indeed, we find that the results follow a systematic trend with the filtered magnetic field angles that can lead to a shift of the result up to 5°. In turn, this means that every value for the interstellar flow longitude derived from the PUI cutoff is affected by a systematic error depending on the utilized magnetic field orientations. Here, we present our observations, discuss possible reasons for the systematic trend we discovered, and indicate selections that may minimize the systematic errors.

  19. THE ROLE OF PICKUP IONS ON THE STRUCTURE OF THE VENUSIAN BOW SHOCK AND ITS IMPLICATIONS FOR THE TERMINATION SHOCK

    International Nuclear Information System (INIS)

    Lu Quanming; Shan Lican; Zhang Tielong; Wu Mingyu; Wang Shui; Zank, Gary P.; Yang Zhongwei; Du Aimin

    2013-01-01

    The recent crossing of the termination shock by Voyager 2 has demonstrated the important role of pickup ions (PUIs) in the physics of collisionless shocks. The Venus Express (VEX) spacecraft orbits Venus in a 24 hr elliptical orbit that crosses the bow shock twice a day. VEX provides a unique opportunity to investigate the role of PUIs on the structure of collisionless shocks more generally. Using VEX observations, we find that the strength of the Venusian bow shock is weaker when solar activity is strong. We demonstrate that this surprising anti-correlation is due to PUIs mediating the Venusian bow shock

  20. Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

    OpenAIRE

    Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

    2016-01-01

    We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle from 2002 to 2013 to verify if solar cycle-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection spe...

  1. Background and Pickup Ion Velocity Distribution Dynamics in Titan's Plasma Environment: 3D Hybrid Simulation and Comparison with CAPS T9 Observations

    Science.gov (United States)

    Lipatov, A. S.; Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

    2011-01-01

    In this report we discuss the ion velocity distribution dynamics from the 3D hybrid simulation. In our model the background, pickup, and ionospheric ions are considered as a particles, whereas the electrons are described as a fluid. Inhomogeneous photoionization, electron-impact ionization and charge exchange are included in our model. We also take into account the collisions between the ions and neutrals. The current simulation shows that mass loading by pickup ions H(+); H2(+), CH4(+) and N2(+) is stronger than in the previous simulations when O+ ions are introduced into the background plasma. In our hybrid simulations we use Chamberlain profiles for the atmospheric components. We also include a simple ionosphere model with average mass M = 28 amu ions that were generated inside the ionosphere. The moon is considered as a weakly conducting body. Special attention will be paid to comparing the simulated pickup ion velocity distribution with CAPS T9 observations. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of the Alfve n wing-like structures. The simulation also shows that the ring-like velocity distribution for pickup ions relaxes to a Maxwellian core and a shell-like halo.

  2. 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.

  3. Resonant pickups for non-destructive single-particle detection in heavy-ion storage rings and first experimental results

    International Nuclear Information System (INIS)

    Sanjari, Mohammad Shahab

    2013-01-01

    Nuclear astrophysics studies on highly charged radionuclides benefit from accelerator facilities with storage rings, where exotic nuclides produced with small yields can be efficiently investigated. Currently there are two accelerator facilities capable of storing highly charged heavy ions, GSI in Darmstadt and IMP in Lanzhou. Non-destructive detection methods are often used for in-flight measurements based on frequency analysis. The sensitivity of such detection systems are of primary importance specially when number of stored ions is small. Furthermore, since the exotic nuclides of interest are as a rule short-lived, the detectors must be fast. One common form of such detectors are parallel plate SCHOTTKY monitors, on which particles induce a mirror charge at each passage. This method has been successfully used at ESR experimental storage ring of GSI since 1991. In this work we describe a new resonant SCHOTTKY pickup operating as a high sensitive cavity current monitor which was mounted and commissioned in the ESR early 2010. It was successfully used in several storage ring experiments. A very similar pickup was mounted in CSRe at IMP Lanzhou in 2011. First in-ring tests have been performed and new experimental results are pending. The spectral analysis of acquired signals by the new detector has enabled a broad range of new physics experiments. The theory of operation and first experimental results and future perspectives are presented in this thesis.

  4. Resonant pickups for non-destructive single-particle detection in heavy-ion storage rings and first experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Sanjari, Mohammad Shahab

    2013-04-26

    Nuclear astrophysics studies on highly charged radionuclides benefit from accelerator facilities with storage rings, where exotic nuclides produced with small yields can be efficiently investigated. Currently there are two accelerator facilities capable of storing highly charged heavy ions, GSI in Darmstadt and IMP in Lanzhou. Non-destructive detection methods are often used for in-flight measurements based on frequency analysis. The sensitivity of such detection systems are of primary importance specially when number of stored ions is small. Furthermore, since the exotic nuclides of interest are as a rule short-lived, the detectors must be fast. One common form of such detectors are parallel plate SCHOTTKY monitors, on which particles induce a mirror charge at each passage. This method has been successfully used at ESR experimental storage ring of GSI since 1991. In this work we describe a new resonant SCHOTTKY pickup operating as a high sensitive cavity current monitor which was mounted and commissioned in the ESR early 2010. It was successfully used in several storage ring experiments. A very similar pickup was mounted in CSRe at IMP Lanzhou in 2011. First in-ring tests have been performed and new experimental results are pending. The spectral analysis of acquired signals by the new detector has enabled a broad range of new physics experiments. The theory of operation and first experimental results and future perspectives are presented in this thesis.

  5. Observations of Low-Frequency Magnetic Waves due to Newborn Interstellar Pickup Ions Using ACE, Ulysses, and Voyager Data

    Science.gov (United States)

    Smith, Charles W.; Aggarwal, Poornima; Argall, Matthew R.; Burlaga, Leonard F.; Bzowski, Maciej; Cannon, Bradford E.; Gary, S. Peter; Fisher, Meghan K.; Gilbert, Jason A.; Hollick, Sophia J.; Isenberg, Philip A.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.; Pine, Zackary B.; Richardson, John D.; Schwadron, Nathan A.; Skoug, Ruth M.; Sokół, Justyna M.; Taylor, David K.; Vasquez, Bernard J.

    2017-09-01

    Wave excitation by newborn interstellar pickup ions (PUIs) plays a significant role in theories that attempt to describe IBEX and Voyager observations in the solar wind and heliosheath. The same dynamic processes can be far-reaching and extend into the inner heliosphere to at least 1AU and likely to smaller heliocentric distances. While the high-resolution magnetic field measurements required to study these waves are not yet available in the heliosheath, we have studied a range of available observations and found evidence of waves due to interstellar PUIs using ACE (1998-2015 at 1 AU), Ulysses (1996-2006 at 2 to 5 AU, high and low latitudes) and Voyager (1978-1979 and 2 to 6 AU) observations. Efforts to extend the Voyager observations to 35 AU are ongoing. We have examined these data sets and report on observations of low-frequency waves that result from newborn interstellar pickup H+ and He+ ions. Although not as common as theory originally predicted, we presently have identified 524 independent occurrences. Our conclusion from studying these waves is that they are seen only when the ambient turbulence is sufficiently weak. The instability that generates these waves requires a slow accumulation of wave energy over several to tens of hours to achieve observable wave amplitudes. In regions where the turbulence is moderate to strong, the turbulence absorbs the wave energy before it can reach observable levels and transports the energy to the dissipation scales where it heats the background thermal particles. Only intervals with the weakest turbulence will permit energy accumulation over this time scale. These conditions are most often, but not exclusively, achieved in solar wind rarefaction regions.

  6. Near Earth Inner-Source and Interstellar Pickup Ions Observed with the Hot Plasma Composition Analyzer of the Magnetospheric Multiscale Mission Mms-Hpca

    Science.gov (United States)

    Gomez, R. G.; Fuselier, S. A.; Mukherjee, J.; Gonzalez, C. A.

    2017-12-01

    Pickup ions found near the earth are generally picked up in the rest frame of the solar wind, and propagate radially outward from their point of origin. While propagating, they simultaneously gyrate about the magnetic field. Pickup ions come in two general populations; interstellar and inner source ions. Interstellar ions originate in the interstellar medium, enter the solar system in a neutral charge state, are gravitationally focused on the side of the sun opposite their arrival direction and, are ionized when they travel near the sun. Inner-source ions originate at a location within the solar system and between the sun and the observation point. Both pickup ion populations share similarities in composition and charge states, so measuring of their dynamics, using their velocity distribution functions, f(v)'s, is absolutely essential to distinguishing them, and to determining their spatial and temporal origins. Presented here will be the results of studies conducted with the four Hot Plasma Composition Analyzers of the Magnetospheric Multiscale Mission (MMS-HPCA). These instruments measure the full sky (4π steradians) distribution functions of near earth plasmas at a 10 second cadence in an energy-to-charge range 0.001-40 keV/e. The instruments are also capable of parsing this combined energy-solid angle phase space with 22.5° resolution polar angle, and 11.25° in azimuthal angle, allowing for clear measurement of the pitch angle scattering of the ions.

  7. Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

    Science.gov (United States)

    Huddleston, D. E.; Johnstone, A. D.

    1992-01-01

    The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

  8. Influence of the Interplanetary Convective Electric Field on the Distribution of Heavy Pickup Ions Around Mars

    Science.gov (United States)

    Johnson, B. C.; Liemohn, M. W.; Fränz, M.; Ramstad, R.; Stenberg Wieser, G.; Nilsson, H.

    2018-01-01

    This study obtains a statistical representation of 2-15 keV heavy ions outside of the Martian-induced magnetosphere and depicts their organization by the solar wind convective electric field (ESW). The overlap in the lifetime of Mars Global Surveyor (MGS) and Mars Express (MEX) provides a period of nearly three years during which magnetometer data from MGS can be used to estimate the direction of ESW in order to better interpret MEX ion data. In this paper we use MGS estimates of ESW to express MEX ion measurements in Mars-Sun-Electric field (MSE) coordinates. A new methodological technique used in this study is the limitation of the analysis to a particular instrument mode for which the overlap between proton contamination and plume observations is rare. This allows for confident energetic heavy ion identification outside the induced magnetosphere boundary. On the dayside, we observe high count rates of 2-15 keV heavy ions more frequently in the +ESW hemisphere (+ZMSE) than in the -ESW hemisphere, but on the nightside the reverse asymmetry was found. The results are consistent with planetary origin ions being picked up by the solar wind convective electric field. Though a field of view hole hinders quantification of plume fluxes and velocity space, this new energetic heavy ion identification technique means that Mars Express should prove useful in expanding the time period available to assess general plume loss variation with drivers.

  9. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. I. New observations and linear analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, FL (United States); Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH (United States); Murphy, Neil [Jet Propulsion Laboratory, Mail Stop 180-600, 4800 Oak Grove Drive, Pasadena, CA (United States); Nuno, Raquel G., E-mail: bc13h@my.fsu.edu, E-mail: Charles.Smith@unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: Neil.Murphy@jpl.nasa.gov, E-mail: raquel.nuno@asu.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States)

    2014-04-01

    We have examined Ulysses magnetic field data using dynamic spectrogram techniques that compute wave amplitude, polarization, and direction of propagation over a broad range of frequencies and time. Events were identified that showed a strong polarization signature and an enhancement of power above the local proton gyrofrequency. We perform a statistical study of 502 wave events in an effort to determine when, where, and why they are observed. Most notably, we find that waves arising from newborn interstellar pickup ions are relatively rare and difficult to find. The quantities normally employed in theories of wave growth are neutral atom density and quantities related to their ionization and the subsequent dynamics such as wind speed, solar wind flux, and magnetic field orientation. We find the observations of waves to be largely uncorrelated to these quantities except for mean field direction where quasi-radial magnetic fields are favored and solar wind proton flux where wave observations appear to be favored by low flux conditions which runs contrary to theoretical expectations of wave generation. It would appear that an explanation based on source physics and instability growth rates alone is not adequate to account for the times when these waves are seen.

  10. Pickup Ion Dynamics in the Outer Heliosheath Associated with the Growth of Kelvin-Helmholtz Instability at the Heliopause

    Science.gov (United States)

    Tsubouchi, K.

    2017-12-01

    A discovery of "IBEX ribbon", localized bright emission of energetic neutral atoms, has brought new insights into the plasma environment of its source region beyond the heliosphere. It has been basically established that its geometrical property is associated with the local interstellar magnetic field draped on the heliopause, and pickup ions (PUIs) in the outer heliosheath (OHS) must be its primary source particles. Understanding the PUI dynamics in OHS more in detail is our motivation for this study. We performed two-dimensional hybrid simulations to evaluate the response of PUIs to the structural variation in the heliosheath. We assumed the simulation system such that the background plasma is hot solar wind in the inner heliosheath and cold interstellar plasma in OHS, and the directions of these flows are tangential to the heliopause. Such a situation leads to the growth of Kelvin-Helmholtz instability (KHI), where the plasma mixing and turbulence excitation takes place. We identified that non-stationarity and non-uniformity emerges in the PUI density structure in a specific energy range as KHI process advances. Relevance of these results to the expected observation like IBEX ribbon will be discussed.

  11. Solar cycle variation of interstellar neutral He, Ne, O density and pick-up ions along the Earth's orbit

    Science.gov (United States)

    Sokół, Justyna M.; Bzowski, Maciej; Kubiak, Marzena A.; Möbius, Eberhard

    2016-06-01

    We simulated the modulation of the interstellar neutral (ISN) He, Ne, and O density and pick-up ion (PUI) production rate and count rate along the Earth's orbit over the solar cycle (SC) from 2002 to 2013 to verify if SC-related effects may modify the inferred ecliptic longitude of the ISN inflow direction. We adopted the classical PUI model with isotropic distribution function and adiabatic cooling, modified by time- and heliolatitude-dependent ionization rates and non-zero injection speed of PUIs. We found that the ionization losses have a noticeable effect on the derivation of the ISN inflow longitude based on the Gaussian fit to the crescent and cone peak locations. We conclude that the non-zero radial velocity of the ISN flow and the energy range of the PUI distribution function that is accumulated are of importance for a precise reproduction of the PUI count rate along the Earth orbit. However, the temporal and latitudinal variations of the ionization in the heliosphere, and particularly their variation on the SC time-scale, may significantly modify the shape of PUI cone and crescent and also their peak positions from year to year and thus bias by a few degrees the derived longitude of the ISN gas inflow direction.

  12. Pickup ion processes associated with spacecraft thrusters: Implications for solar probe plus

    Energy Technology Data Exchange (ETDEWEB)

    Clemens, Adam, E-mail: a.j.clemens@qmul.ac.uk; Burgess, David [School of Physics and Astronomy, Queen Mary University of London, London (United Kingdom)

    2016-03-15

    Chemical thrusters are widely used in spacecraft for attitude control and orbital manoeuvres. They create an exhaust plume of neutral gas which produces ions via photoionization and charge exchange. Measurements of local plasma properties will be affected by perturbations caused by the coupling between the newborn ions and the plasma. A model of neutral expansion has been used in conjunction with a fully three-dimensional hybrid code to study the evolution and ionization over time of the neutral cloud produced by the firing of a mono-propellant hydrazine thruster as well as the interactions of the resulting ion cloud with the ambient solar wind. Results are presented which show that the plasma in the region near to the spacecraft will be perturbed for an extended period of time with the formation of an interaction region around the spacecraft, a moderate amplitude density bow wave bounding the interaction region and evidence of an instability at the forefront of the interaction region which causes clumps of ions to be ejected from the main ion cloud quasi-periodically.

  13. Medium-energy ion reflection from solids

    CERN Document Server

    Mashkova, ES

    1985-01-01

    ``Medium-Energy Ion Reflection from Solids'' analyses the results of experimental, theoretical and computer investigations on the process of scattering of ions by solid surfaces. Surface scattering is a relatively young and rapidly developing branch of the physics of atomic collisions and the literature on this subject has rapidly grown.As the first monograph devoted specifically to surface scattering of ions, this book is directed at scientists involved in ion-solid interaction studies.

  14. INTERSTELLAR PICKUP ION ACCELERATION IN THE TURBULENT MAGNETIC FIELD AT THE SOLAR WIND TERMINATION SHOCK USING A FOCUSED TRANSPORT APPROACH

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Junye; Roux, Jakobus A. le; Arthur, Aaron D. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2016-08-01

    We study the physics of locally born interstellar pickup proton acceleration at the nearly perpendicular solar wind termination shock (SWTS) in the presence of a random magnetic field spiral angle using a focused transport model. Guided by Voyager 2 observations, the spiral angle is modeled with a q -Gaussian distribution. The spiral angle fluctuations, which are used to generate the perpendicular diffusion of pickup protons across the SWTS, play a key role in enabling efficient injection and rapid diffusive shock acceleration (DSA) when these particles follow field lines. Our simulations suggest that variation of both the shape ( q -value) and the standard deviation ( σ -value) of the q -Gaussian distribution significantly affect the injection speed, pitch-angle anisotropy, radial distribution, and the efficiency of the DSA of pickup protons at the SWTS. For example, increasing q and especially reducing σ enhances the DSA rate.

  15. On ion injection at quasiparallel shocks

    International Nuclear Information System (INIS)

    Scholer, M.; Kucharek, H.; Kato, C.

    2002-01-01

    A large number of numerical experiments has been performed in order to study the interaction of interstellar pickup protons and helium ions with quasiparallel collisionless shocks. The shocks are modeled by a one-dimensional hybrid simulation method which treats the ions as macroparticles and the electrons as a massless fluid. Solar wind alpha particles and pickup protons are included self-consistently. In addition, the particle splitting method is used for the solar wind ions so that the distribution function can be followed over more than 10 orders of magnitude. A large part of the pickup ion distribution is reflected; the reflection efficiency is very high, and can reach in cases where the pickup ion density is low as much as 50%-60%. The reflection efficiency is almost independent of magnetic field-shock normal angle. This indicates that magnetic mirroring is unimportant and does not lead to larger reflection efficiencies. The reflection efficiency of pickup protons rapidly decreases when the pickup ion density exceeds a few percent of the solar wind density. An addition of 25% pickup protons decreases the reflection coefficient for these ions to ∼10%. This represents the fact that a quasiparallel shock cannot be considered as being uncoupled from the upstream region: at high additions of pickup ions the shock structure is changed in such a way as to reflect less pickup ions. The intensity of diffuse ions upstream of a quasiparallel shock does not depend on the temperature of the core distribution. Within the framework of the present model even solar wind distributions with a hard power law tail do not produce higher intensities of diffuse ions. It is argued that this can be understood by the fact that the intrinsic self-consistency between the processes in the upstream region and at the shock transition determines the injection and reflection properties of the core solar wind distribution

  16. THE IBEX RIBBON AND THE PICKUP ION RING STABILITY IN THE OUTER HELIOSHEATH. II. MONTE-CARLO AND PARTICLE-IN-CELL MODEL RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Niemiec, J. [Institute of Nuclear Physics PAN, Radzikowskiego 152 31-342 Krakow (Poland); Florinski, V.; Heerikhuisen, J. [Department of Space Science and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Nishikawa, K.-I., E-mail: jacek.niemiec@ifj.edu.pl, E-mail: vaf0001@uah.edu, E-mail: jh0004@uah.edu, E-mail: ken-ichi.nishikawa-1@nasa.gov [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2016-08-01

    The nearly circular ribbon of energetic neutral atom (ENA) emission discovered by NASA’s Interplanetary Boundary EXplorer satellite ( IBEX ), is most commonly attributed to the effect of charge exchange of secondary pickup ions (PUIs) gyrating about the magnetic field in the outer heliosheath (OHS) and the interstellar space beyond. The first paper in the series (Paper I) presented a theoretical analysis of the pickup process in the OHS and hybrid-kinetic simulations, revealing that the kinetic properties of freshly injected proton rings depend sensitively on the details of their velocity distribution. It was demonstrated that only rings that are not too narrow (parallel thermal spread above a few km s{sup −1}) and not too wide (parallel temperature smaller than the core plasma temperature) could remain stable for a period of time long enough to generate ribbon ENAs. This paper investigates the role of electron dynamics and the extra spatial degree of freedom in the ring ion scattering process with the help of two-dimensional full particle-in-cell (PIC) kinetic simulations. A good agreement is observed between ring evolution under unstable conditions in hybrid and PIC models, and the dominant modes are found to propagate parallel to the magnetic field. We also present more realistic ribbon PUI distributions generated using Monte Carlo simulations of atomic hydrogen in the global heliosphere and examine the effect of both the cold ring-like and the hot “halo” PUIs produced from heliosheath ENAs on the ring stability. It is shown that the second PUI population enhances the fluctuation growth rate, leading to faster isotropization of the solar-wind-derived ring ions.

  17. Observations from 1 to 6 AU of Low-Frequency Magnetic Waves due to Newborn Interstellar Pickup Ions Using Ulysses, Voyager and ACE Data

    Science.gov (United States)

    Smith, C. W.; Aggarwal, P.; Argall, M. R.; Burlaga, L. F.; Bzowski, M.; Cannon, B. E.; Gary, S. P.; Fisher, M. K.; Gilbert, J. A.; Hollick, S. J.; Isenberg, P. A.; Joyce, C. J.; Murphy, N.; Nuno, R. G.; Pine, Z. B.; Richardson, J. D.; Schwadron, N.; Skoug, R. M.; Sokol, J. M.; Taylor, D. K.; Vasquez, B. J.; Zurbuchen, T.

    2016-12-01

    Wave excitation by newborn interstellar pickup ions (PUIs) play a significant role in theories that attempt to describe IBEX and Voyager observations in the heliosheath as well as solar wind heating. The same dynamic processes can be far-reaching and extend into the inner heliosphere to at least 1AU and likely to smaller heliocentric distances. While the high-resolution magnetic field measurements required to study these waves are not yet available in the heliosheath, we have studied a range of available observations and found evidence of waves due to interstellar PUIs using ACE (1998-2015 at 1 AU), Ulysses (1996-2006 at 2 to 5 AU, high and low latitudes) and Voyager (1978-1979 and 2 to 6 AU) observations. Efforts to extend the Voyager observations to 35 AU are ongoing. We have examined these data sets and report on observations of low-frequency waves that result from newborn interstellar pickup H+ and He+ ions. Although not as common as theory once predicted, we presently have identified 524 independent occurrences. Our conclusion from studying these waves is that they are seen only when the ambient turbulence is sufficiently weak. The instability that leads to the generation of these waves requires a slow accumulation of wave energy over several to tens of hours to achieve the observed wave amplitudes. In regions where the turbulence is moderate to strong, the turbulence consumes the wave energy before it can reach observable levels and transports the energy to the dissipation scales where it heats the background thermal particles. Only intervals with the weakest turbulence will permit energy accumulation over this time scale. These conditions are most often, but not exclusively, achieved in solar wind rarefaction regions.

  18. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, FL 32306 (United States); Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 (United States); Murphy, Neil [Jet Propulsion Laboratory, Mail Stop 180-600, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Nuno, Raquel G., E-mail: bc13h@my.fsu.edu, E-mail: Charles.Smith@unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: cjl46@wildcats.unh.edu, E-mail: Neil.Murphy@jpl.nasa.gov, E-mail: raquel.nuno@asu.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)

    2014-06-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  19. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    International Nuclear Information System (INIS)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

    2014-01-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  20. Electrostatic pickup station

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    Electrostatic pickup station, with 4 interleaved electrodes, to measure beam position in the horizontal and vertical plane. This type is used in the transfer lines leaving the PS (TT2, TT70, TTL2). See also 7904075.

  1. Structure of the Heliotail from Interstellar Boundary Explorer Observations: Implications for the 11-year Solar Cycle and Pickup Ions in the Heliosheath

    Energy Technology Data Exchange (ETDEWEB)

    Zirnstein, E. J.; McComas, D. J. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Heerikhuisen, J.; Zank, G. P.; Pogorelov, N. V. [Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Funsten, H. O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Reisenfeld, D. B. [Department of Physics and Astronomy, University of Montana, Missoula, MT 59812 (United States); Schwadron, N. A., E-mail: ejz@princeton.edu [Southwest Research Institute, San Antonio, TX 78228 (United States)

    2017-02-20

    Interstellar Boundary Explorer ( IBEX ) measurements of energetic neutral atoms (ENAs) from the heliotail show a multi-lobe structure of ENA fluxes as a function of energy between ∼0.71 and 4.29 keV. Below ∼2 keV, there is a single structure of enhanced ENA fluxes centered near the downwind direction. Above ∼2 keV, this structure separates into two lobes, one north and one south of the solar equatorial plane. ENA flux from these two lobes can be interpreted as originating from the fast solar wind (SW) propagating through the inner heliosheath (IHS). Alternatively, a recently published model of the heliosphere suggests that the heliotail may split into a “croissant-like” shape, and that such a geometry could be responsible for the heliotail ENA feature. Here we present results from a time-dependent simulation of the heliosphere that produces a comet-like heliotail, and show that the 11-year solar cycle leads to the formation of ENA lobes with properties remarkably similar to those observed by IBEX . The ENA energy at which the north and south lobes appear suggests that the pickup ion (PUI) temperature in the slow SW of the IHS is ∼10{sup 7} K. Moreover, we demonstrate that the extinction of PUIs by charge-exchange is an essential process required to create the observed global ENA structure. While the shape and locations of the ENA lobes as a function of energy are well reproduced by PUIs that cross the termination shock, the results appear to be sensitive to the form of the distribution of PUIs injected in the IHS.

  2. The Role of Pickup Ion Dynamics Outside of the Heliopause in the Limit of Weak Pitch Angle Scattering: Implications for the Source of the IBEX Ribbon

    Science.gov (United States)

    Zirnstein, E. J.; Heerikhuisen, J.; Dayeh, M. A.

    2018-03-01

    We present a new model of the Interstellar Boundary Explorer (IBEX) ribbon based on the secondary energetic neutral atom (ENA) mechanism, under the assumption that there is negligible pitch angle scattering of pickup ions (PUIs) outside the heliopause. Using the results of an MHD-plasma/kinetic-neutral simulation of the heliosphere, we generate PUIs in the outer heliosheath, solve their transport using guiding center theory, and compute ribbon ENA fluxes at 1 au. We implement several aspects of the PUI dynamics, including (1) parallel motion along the local interstellar magnetic field (ISMF), (2) advective transport with the interstellar plasma, (3) the mirror force acting on PUIs propagating along the ISMF, and (4) betatron acceleration of PUIs as they are advected within an increasing magnetic field toward the heliopause. We find that ENA fluxes at 1 au are reduced when PUIs are allowed to move along the ISMF, and ENA fluxes are reduced even more by the inclusion of the mirror force, which pushes particles away from IBEX lines of sight. Inclusion of advection and betatron acceleration do not result in any significant change in the ribbon. Interestingly, the mirror force reduces the ENA fluxes from the inner edge of the ribbon more than those from its outer edge, effectively reducing the ribbon’s width by ∼6° and increasing its radius projected on the sky. This is caused by the asymmetric draping of the ISMF around the heliopause, such that ENAs from the ribbon’s inner edge originate closer to the heliopause, where the mirror force is strongest.

  3. Electrostatic pickup station

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    Electrostatic pickup station, with 4 electrodes, to measure beam position in the horizontal and vertical plane. This type is used in the transfer lines leaving the PS (TT2, TTL2, TT70). See also 8206063, where the electrode shapes are clearly visible.

  4. AA, stochastic precooling pickup

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The freshly injected antiprotons were subjected to fast stochastic "precooling". In this picture of a precooling pickup, the injection orbit is to the left, the stack orbit to the far right. After several seconds of precooling with the system's kickers (in momentum and in the vertical plane), the precooled antiprotons were transferred, by means of RF, to the stack tail, where they were subjected to further stochastic cooling in momentum and in both transverse planes, until they ended up, deeply cooled, in the stack core. During precooling, a shutter near the central orbit shielded the pickups from the signals emanating from the stack-core, whilst the stack-core was shielded from the violent action of the precooling kickers by a shutter on these. All shutters were opened briefly during transfer of the precooled antiprotons to the stack tail. Here, the shutter is not yet mounted. Precooling pickups and kickers had the same design, except that the kickers had cooling circuits and the pickups had none. Peering th...

  5. Pickup protons at quasi-perpendicular shocks: full particle electrodynamic simulations

    Directory of Open Access Journals (Sweden)

    S. Matsukiyo

    2007-02-01

    Full Text Available We have performed 3 one-dimensional full particle electromagnetic simulations of a quasi-perpendicular shock with the same Alfvén Mach number MA~5, shock normal-magnetic field angle ΘBn=87° and ion and electron beta (particle to magnetic field pressure of 0.1. In the first run we used an ion to electron mass ratio close to the physical one (mi/me=1024. As expected from previous high mass ratio simulations the Modified Two-Stream instability develops in the foot of the shock, and the shock periodically reforms itself. We have then self-consistently included in the simulation 10% pickup protons distributed on a shell in velocity space as a third component. In a run with an unrealistically low mass ratios of 200 the shock still reforms itself; reformation is due to accumulation of specularly reflected particles at the upstream edge of the foot. In a third run including pickup protons we used a mass ratio of 1024. The shock reforms periodically as in the low mass ratio run with a somewhat smaller time constant. The specular reflection of pickup protons results in an increase of the shock potential some distance ahead of the shock foot and ramp. The minimum scale of the cross shock potential during reformation is about 7 electron inertial length λe. We do not find any pickup proton acceleration in the ramp or downstream of the shock beyond the energy which specularly reflected ions gain by the motional electric field of the solar wind during their upstream gyration.

  6. Pickup protons at quasi-perpendicular shocks: full particle electrodynamic simulations

    Directory of Open Access Journals (Sweden)

    S. Matsukiyo

    2007-02-01

    Full Text Available We have performed 3 one-dimensional full particle electromagnetic simulations of a quasi-perpendicular shock with the same Alfvén Mach number MA~5, shock normal-magnetic field angle ΘBn=87° and ion and electron beta (particle to magnetic field pressure of 0.1. In the first run we used an ion to electron mass ratio close to the physical one (mi/me=1024. As expected from previous high mass ratio simulations the Modified Two-Stream instability develops in the foot of the shock, and the shock periodically reforms itself. We have then self-consistently included in the simulation 10% pickup protons distributed on a shell in velocity space as a third component. In a run with an unrealistically low mass ratios of 200 the shock still reforms itself; reformation is due to accumulation of specularly reflected particles at the upstream edge of the foot. In a third run including pickup protons we used a mass ratio of 1024. The shock reforms periodically as in the low mass ratio run with a somewhat smaller time constant. The specular reflection of pickup protons results in an increase of the shock potential some distance ahead of the shock foot and ramp. The minimum scale of the cross shock potential during reformation is about 7 electron inertial length λe. We do not find any pickup proton acceleration in the ramp or downstream of the shock beyond the energy which specularly reflected ions gain by the motional electric field of the solar wind during their upstream gyration.

  7. The Velocity Distribution Of Pickup He+ Measured at 0.3 AU by MESSENGER

    Science.gov (United States)

    Gershman, Daniel J.; Fisk, Lennard A.; Gloeckler, George; Raines, Jim M.; Slavin, James A.; Zurbuchen, Thomas H.; Solomon, Sean C.

    2014-06-01

    During its interplanetary trajectory in 2007-2009, the MErcury Surface, Space ENvrionment, GEochemistry, and Ranging (MESSENGER) spacecraft passed through the gravitational focusing cone for interstellar helium multiple times at a heliocentric distance R ≈ 0.3 AU. Observations of He+ interstellar pickup ions made by the Fast Imaging Plasma Spectrometer sensor on MESSENGER during these transits provide a glimpse into the structure of newly formed inner heliospheric pickup-ion distributions. This close to the Sun, these ions are picked up in a nearly radial interplanetary magnetic field. Compared with the near-Earth environment, pickup ions observed near 0.3 AU will not have had sufficient time to be energized substantially. Such an environment results in a nearly pristine velocity distribution function that should depend only on pickup-ion injection velocities (related to the interstellar gas), pitch-angle scattering, and cooling processes. From measured energy-per-charge spectra obtained during multiple spacecraft observational geometries, we have deduced the phase-space density of He+ as a function of magnetic pitch angle. Our measurements are most consistent with a distribution that decreases nearly monotonically with increasing pitch angle, rather than the more commonly modeled isotropic or hemispherically symmetric forms. These results imply that pitch-angle scattering of He+ may not be instantaneous, as is often assumed, and instead may reflect the velocity distribution of initially injected particles. In a slow solar wind stream, we find a parallel-scattering mean free path of λ || ~ 0.1 AU and a He+ production rate of ~0.05 m-3 s-1 within 0.3 AU.

  8. Reflection of ion acoustic solitons in a plasma having negative ions

    International Nuclear Information System (INIS)

    Chauhan, S.S.; Malik, H.K.; Dahiya, R.P.

    1996-01-01

    Reflection of compressive and rarefactive ion acoustic solitons propagating in an inhomogeneous plasma in the presence of negative ions is investigated. Modified Korteweg endash deVries equations for incident and reflected solitons are derived and solved. The amplitude of incident and reflected solitons increases with negative to positive ion density ratio. With increasing density ratio, reflection of rarefactive solitons is reinforced whereas that of compressive solitons weakened. The rarefactive solitons are found to undergo stronger reflection than the compressive ones. copyright 1996 American Institute of Physics

  9. Reflection properties of hydrogen ions at helium irradiated tungsten surfaces

    International Nuclear Information System (INIS)

    Doi, K; Tawada, Y; Kato, S; Sasao, M; Kenmotsu, T; Wada, M; Lee, H T; Ueda, Y; Tanaka, N; Kisaki, M; Nishiura, M; Matsumoto, Y; Yamaoka, H

    2016-01-01

    Nanostructured W surfaces prepared by He bombardment exhibit characteristic angular distributions of hydrogen ion reflection upon injection of 1 keV H + beam. A magnetic momentum analyzer that can move in the vacuum chamber has measured the angular dependence of the intensity and the energy of reflected ions. Broader angular distributions were observed for He-irradiated tungsten samples compared with that of the intrinsic polycrystalline W. Both intensity and energy of reflected ions decreased in the following order: the polycrystalline W, the He-bubble containing W, and the fuzz W. Classical trajectory Monte Carlo simulations based on Atomic Collision in Amorphous Target code suggests that lower atom density near the surface can make the reflection coefficients lower due to increasing number of collisions. (paper)

  10. Ion Dynamics at Shocks: Ion Reflection and Beam Formation at Quasi-perpendicular Shocks

    International Nuclear Information System (INIS)

    Kucharek, Harald; Moebius, Eberhard

    2005-01-01

    The physics of collisionless shocks is controlled by the ion dynamics. The generation of gyrating ions by reflection as well as the formation of field-aligned ion beams are essential parts of this dynamic. On the one hand reflection is most likely the first interaction of ions with the shock before they undergo the downstream thermalization process. On the other hand field-aligned ion beams, predominately found at the quasi-perpendicular bow shock, propagate into the distant foreshock region and may create wave activity. We revisit ion reflection, the source and basic production mechanism of field-aligned ion beams, by using multi-spacecraft measurements and contrast these observations with existing theories. Finally, we propose an alternative production mechanism

  11. Effects of time-dependent photoionization on interstellar pickup atoms

    International Nuclear Information System (INIS)

    Isenberg, P.A.; Lee, M.A.

    1995-01-01

    We present an analytical model for the density variations of interstellar pickup ions in the solar wind due to a time-dependent variation in the photoionization rate, our model predicts a pickup ion density enhancement lasting for a time of the order of the duration of the increase plus the solar wind convection time to the observation point. If the photoionization rate returns to its initial value, this enhancement is followed by a decreased pickup ion density resulting from a depleted interstellar neutral particle density. In the absence of further variations in the photoionization rate, the pickup ion density recovers on a time which scales as the radial position of the observation point divided by the inflow speed of the neutral particles. Gradual variations in the photoionization rate result in a pickup ion density which tends to track the ionization rate, though the density variations are smoothed and delayed in time due to the solar wind convection of ions picked up at points closer to the Sun. 27 refs., 4 figs

  12. AA precooling pickup

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The freshly injected antiprotons, while circulating on the injection orbit, were subjected to fast stochastic "precooling" for several seconds (in momentum and in the vertical plane). This precooling pickup is being readied by Gerard Laurent for installation in its tank. Precooling PUs and kickers were of identical construction (except for the kickers having cooling circuits), with C-shaped ferrites sandwiched between C-shaped metal plates and couplers at the back of the C. For reasons explained in 8002234, they were also equipped with shutters which closed the open side of the C when there was beam on the injection orbit. For more on precooling see 8020234, 8004064.

  13. Reflection of slow hydrogen and helium ions from solid surfaces

    International Nuclear Information System (INIS)

    Akkerman, A.F.

    1978-01-01

    Some characteristics of the proton and helium ion flux (E < 10 keV), reflected from solid surfaces are presented. A 'condensed walk' scheme, previously used for electron transport calculations, was adapted. Results obtained either by the scheme or by a more detailed 'consequent' scheme agreed closely. The presented data permit calculations of the mean energy of reflected particles and other values for various energy and angular distributions of incident particles. (author)

  14. Dynamic devices - pickups and kickers

    International Nuclear Information System (INIS)

    Lambertson, G.

    1986-08-01

    A given configuration of electrodes may be used either as a pickup or as a kicker; that duality is addressed. Some general relations between longitudinal and transverse effects and between the respones as pickup and as kicker are derived. Dynamic effects are seen to be entirely determined by the longitudinal electric fields in the direction of the beam current when the electrode is excited as a kicker. Response functions that serve as figures of merit are defined. The responses of specific examples of pickups and kickers are analyzed. An approach to the calculation of the transverse variation of coupling over the electrode aperture is preented

  15. Reflection of ion acoustic waves by the plasma sheath

    International Nuclear Information System (INIS)

    Ibrahim, I.; Kuehl, H.H.

    1984-01-01

    The reflection coefficient R for linear monochromatic ion acoustic waves incident on the transonic layer and sheath from the plasma interior is calculated. The treatment differs from previous analyses in that (1) the exact zero-order ion density and velocity profiles for a planar, bounded plasma are used, and the zero-order charge separation is not neglected, and (2) the first-order quantities near the transonic layer are considered in detail, including first-order charge separation, whereby it is found that no coupling to the beam modes exists, and that the functional form of the first-order solution is completely determined. It is shown that the upper bound for Vertical BarRVertical Bar is (1)/(3) . The largest reflection occurs for frequencies which are small compared with the ionization frequency, and generally decreases with increasing frequency. By Fourier superposition, the reflection of a pulse is computed. For a narrow incident pulse, the reflected pulse is greatly distorted and is small compared with the incident pulse. For a broad pulse, the reflected pulse is similar in shape to the incident pulse, and has a magnitude which is approximately (1)/(3) of the incident pulse

  16. High-performance pickups for beam diagnostics. Design, analysis, characterization and implementation

    International Nuclear Information System (INIS)

    Angelovski, Aleksandar

    2015-01-01

    This work introduces the design, analysis, characterization and implementation of high-performance pickups for two beam diagnostic instruments, a Bunch Arrival-time Monitor (BAM) and an Energy Beam Position Monitor (EBPM) at the European XFEL. As a part of the BAM the cone-shaped pickups are proposed along with the corresponding RF-frontend. The designed pickups deliver a beam induced signal with a slope steepness of around 400 mV/ps and a bandwidth of 40 GHz. These signal characteristics are well inside the design requirements, i.e., a slope steepness of 300 mV/ps and more than ten times better compared to the signal from the state-of-the-art pickups. The pickups are installed and commissioned at three accelerator facilities, FLASH at DESY, the quasi-CW SRF accelerator ELBE at the Helmholtz-Zentrum Dresden-Rossendorf and the SwissFEL injector test facility at Paul Scherrer Institute. The obtained measurement results from the installed pickups are in good agreement with the simulations. A comparison between the signal measurements with the cone-shaped pickup and the state-of-the-art is performed at ELBE showing an improvement by a factor of ten. The potential of the pickups for sub-10 fs arrival-time measurements for bunch charges of 20 pC is demonstrated at ELBE and at SwissFEL injector test facility. The introduced coneshaped pickups are the first commercially available pickups with a bandwidth of up to 40 GHz. For the EBPM, a modular pickup structure with two types of planar pickups, microstrip transmission line and grounded coplanar waveguide with perpendicular connectors is investigated. The transition region between the connector and the line is optimized for two substrate materials, alumina and glass with a reflection coefficient better than -20 dB up to 6 GHz.

  17. AA, closed orbit observation pickup

    CERN Multimedia

    1980-01-01

    Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The small ones, like the one we see here, were inserted into the vacuum chamber of the BLG (long and narrow) bending magnets. See also 8001372, 8010042, 8010045

  18. AA, closed orbit observation pickup

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The wide ones (very wide indeed: 70 cm), like the one we see here, were placed inside the vacuum chamber of the wide quadrupoles QFW, at maximum dispersion. See also 8001372, 8001383, 8010045

  19. AA, closed orbit observation pickup

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The wide ones (very wide indeed: 70 cm), like the one we see here, were placed inside the vacuum chamber of the wide quadrupoles, QFW, at maximum dispersion. See also 8001372,8001383, 8010042

  20. AA, closed orbit observation pickup

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    Electrostatic pickups around the circumference of the AA served for the measurement of the closed orbits across the wide momentum range of +- 3% to either side of central orbit. The pickups were of the "shoebox" type, with diagonal cuts, a horizontal and a vertical one mechanically coupled together. They were located where they would not require extra space. The small ones, like the one we see here, were inserted into the vacuum chamber of the BLG (long and narrow) bending magnets. Werner Sax contemplates his achievement. See also 8001383, 8010042, 8010045.

  1. Beam-phase monitoring with non-destructive pickup

    International Nuclear Information System (INIS)

    Bogaty, J.; Clifft, B.E.

    1995-01-01

    An intensity and phase-sensitive capacitive pickup was installed at the entrance to the PII linac. This device is based on an extension of the design of the Beam Current Monitor developed as part of the ATLAS radiation safety system. The purpose of the pickup is to allow the arrival phase of the beam from the ECR source at the entrance to the PII linac to be set to a standard which reproduces previous tune conditions and establishes a standard. The new pickups and associated electronics demonstrated sensitivity well below 1 electrical nanoamp but can handle beam currents of many electrical microamps as well. In addition to phase information, beam current is also measured by the units thus providing a continuous, non-intercepting current readout as well. From the very first use of PII, we established a few open-quotes reference tunesclose quotes for the linac and scaled those tunes for any other beam desired. For such scaling to work properly, the velocity and phase of the beam from the ion source must be fixed and reproducible. In last year's FWP the new ATLAS Master Oscillator System was described. The new system has the ability of easily adjusting the beam arrival phase at the entrance to each of the major sections of the facility - PII, Booster, ATLAS. Our present techniques for establishing the beam arrival phase at the entrance of each of the linac sections are cumbersome and, sometimes, intellectually challenging. The installation of these capacitative pickups at the entrance to each of the linac sections will make the determination and setting of the beam arrival phase direct, simple, and dynamic. This should dramatically shorten our setup time for open-quotes old-tuneclose quotes configurations and increase useful operating hours. Permanent electronics for the PII entrance pickup is under construction

  2. Survey of coherent ion reflection at the quasi-parallel bow shock

    International Nuclear Information System (INIS)

    Onsager, T.G.; Thomsen, M.F.; Gosling, J.T.; Bame, S.J.; Russell, C.T.

    1990-01-01

    Ions coherently reflected off the Earth's bow shock have previously been observed both when the upstream geometry is quasi-perpendicular and when it is quasi-parallel. In the case of quasiperpendicular geometry, the ions are reflected in a nearly specular manner and are quickly carried back into the shock by the convecting magnetic field. In the quasi-parallel geometry, however, near-specularly reflected ions' guiding center velocities would on the average be directed away from the shock, allowing the ions to escape into the upstream region. The conditions under which coherent reflection occurs and the subsequent coupling of the reflected ions to the incoming solar wind plasma are important factors when assessing the contribution of the reflected ions to the downstream temperature increase and the shock structure. The survey presented in this paper, along with previously reported observations, suggests that near-specularly reflected ions are indeed an important aspect of energy dissipation at the Earth's quasi-parallel bow shock. The authors find that (1) cool, coherent, near-specularly reflected ion beams are detected over nearly the full range of upstream plasma paraameters commonly found at the Earth's bow shock; (2) the beams are typically observed only near the shock ramp or some shock-like feature; and (3) the observed beam velocities are almost always consistent with what one would expect for near-specularly reflected ions after only a small fraction of a gyroperiod following reflection. The second and third points indicate that the beams spread very quickly in velocity space. This spread in velocities could be due either to interactions between the beam and incoming solar wind ions or to some initially small velocity spread in the beam

  3. Five Characteristics of China Made Pickup

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    <正> Compared with imported ones, the domestic-made pick-ups have the characteristics as follows: Technology: over the past several years, along with the fierce market competition, the technologies of over 30 pick-up makers in China seem to be mature. Some makers have possessed a production capacity of 30,000 units every

  4. Reflected and diffuse ions backstreaming from the earth's bow shock 1. Basic properties

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.

    1981-01-01

    Plasma data supplied by the ISEE 2 solar wind experiment are used to perform the first extended statistical analysis of the basic moments of the ions backstream from the earth's bow shock. The analysis is based on 3253 ion spectra, corresponding to a total observation time of approx. =87 hours. It turns out that the density and total energy density of the backstream ions are, on the average, equal to approx. =1% and approx. =10% of those of the solar wind, respectively. The distinction between the 'reflected' and 'diffuse' populations has been confirmed and put on a quantitive basis using the ratio A = V /sub B/P/w/sub B/P between the bulk velocity and the rms thermal speed of the ions. The reflected ions are characterized by a bulk velocity V/sub B/P of the order of 2 times the solar wind velocity and by a temperature of approx.7 x 10 6 K. In contrast, the diffuse ions have, on the average, a bulk velocity 1.2 times the solar wind velocity and a temperature of 40 x 10 6 K. Therefore the total energy density of the diffuse ions is approx. =30% larger than that of the reflected ions. Finally, the kinetic and thermal energy densities are distributed quite differently in the two ion populations: in fact, approx. =70% of the total energy density is kinetic for the reflected ions, while this percentage decreases to approx. =20% for the diffuse ions

  5. Characteristics of reflected and diffuse ions upstream from the earth's bow shock

    International Nuclear Information System (INIS)

    Paschmann, G.; Sckopke, N.; Papamastorakis, I.; Asbridge, J.R.; Bame, S.J.; Gosling, J.T.

    1981-01-01

    The distinction between two types of upstream ion populations has been made on the basis of pronounced differences in their distribution functions. The 'reflected' ions represent a fast beam with temperatures typically 1 to 5 times 10 6 K and speeds up to five times the solar wind speed. An important feature of the reflected ion distributions in their strong temperature anisotropy, with T/sub perpendicular/ exceeding T/sub parallel/ by a factor of two to three. In contrast, the 'diffuse' ions occupy a much larger region of phase space, both in energy and angle; their distribution function generally has the form roughly of a circular ridge in 2 dimensions and a spherical shell in 3 dimensions. Accordingly, their temperature is much larger (> or approx. =10 7 K), and their bulk speed typically is smaller than the solar wind speed. Both ion populations have densities of the order of 0.1 cm -3 . At times transitions between the two extremes, represented by the reflected and diffuse ion populations, are observed. These 'intermediate' distributions are cresent shaped, with the center of curvature near the solar wind velocity. This property suggests that the intermediate distributions result from pitch angle scattering of the reflected beams in the solar wind frame and supports the idea that the reflected ions are the origin of the diffuse ions. At times the diffuse ion distributions exhibit considerable structure and rapid temporal variations. Reflected and diffuse ions can also be distinguished by their occurrence as a function of the angle theta between the local shock normal and the interplanetary magnetic field. Whereas the diffuse ions occur predominantly for small theta, the reflected ions are observed most frequently for theta> or approx. =45 0

  6. Comparison between arc drops in ignited thermionic converters with and without ion reflections at the emitter

    International Nuclear Information System (INIS)

    Lundgren, L.

    1985-01-01

    The output performance of two thermionic energy converters is compared. One converter has a normal emitter, working with zero field at the emitter which is close to the optimum working point, and the other has a low work function emitter and ion reflection at the emitter. A simple model of the plasma and the sheaths shows that a converter working with a low work function emitter and ion reflections gives a worse performance than a similar converter with a normal emitter

  7. Alteration of the UV-visible reflectance spectra of H2O ice by ion bombardment

    Science.gov (United States)

    Sack, N. J.; Boring, J. W.; Johnson, R. E.; Baragiola, R. A.; Shi, M.

    1991-01-01

    Satellite in the Jovian and Saturnian system exhibit differences in reflectivity between their 'leading' and 'trailing' surfaces which can affect the local vapor pressure. Since these differences are thought to be due to differences in the flux of bombarding magnetospheric ions, the influence of ion impact on the UV-visible reflectance of water ice surfaces (20-90 K) by keV ion bombardment was studied. An observed decrease in reflectance in the UV is attributed to rearrangement processes that affect the physical microstructure and surface 'roughness'. The ratio in reflectance of bombarded to freshly deposited films is compared to the ratio of the reflectance of the leading and trailing hemispheres for Europa and Ganymede.

  8. Reflection and transmission of ion acoustic waves from a plasma discontinuity

    International Nuclear Information System (INIS)

    Gary, S.P.; Alexeff, I.; Bloomberg, H.W.

    1975-01-01

    Transmission and reflection coefficients are calculated for an ion acoustic wave incident from the upstream direction upon a plasma discontinuity of width much less than the wavelength. In the limit of an infinitely strong discontinuity there is complete in phase reflection. (U.S.)

  9. Influence of copper single crystal structures on the reflection of low energy hydrogen and helium ions

    International Nuclear Information System (INIS)

    Feijen, H.H.W.

    1975-01-01

    A theoretical basis for the 'wedge-focussing' phenomenon is outlined. Investigations have been made to check up to what extent proton reflection can be simulated by using H 2 + or H 3 + as incident ions and analysing the reflected protons. The results of an experimental study of the influence of surface semi-channels on the reflection of low energy ( + , H 2 + and He + ions from copper single crystals with attention to the wedge-focussing effect are presented (G.T.H.)

  10. Reflection and absorption of ion-acoustic waves in a plasma density gradient

    International Nuclear Information System (INIS)

    Ishihara, O.

    1977-01-01

    Plasma is characterized by electrical quasineutrality and the collective behavior. There exists a longitudinal low-frequency wave called an ion-acoustic wave in a plasma. One problem in the experimental study of ion-acoustic waves has been that sometimes they are observed to be reflected from discharge tube walls, and sometimes to be absorbed. Theoretical computation reveals that a velocity gradient produced by a density gradient plays a significant role in the reflection. The velocity gradient produces the subsonic-supersonic transition and long wavelength waves are reflected before reaching the transition while short wavelength waves penetrate over the transition and are absorbed in the supersonic flow plasma

  11. Reflected and diffuse ions backstreaming from the earth's bow shock 2. Origin

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.

    1981-01-01

    The morphology of the foreshock region and the origin of the 'reflected' and 'diffuse' ion populations are investigated for the first time through an extended statistical analysis. Data are supplied by the solar wind experiment on the satellite ISEE 2 in the period November 5 to December 20, 1977. It is confirmed, on a statistical basis, that quasi-perpendicular shock structures generate beams of reflected ions which propagate along the interplanetary magnetic field lines against the incoming solar wind. Diffuse ions are at least in part originated by the disruption of the reflected beams due to some plasma instability, having a growth time of the order of a few tens of seconds. A preliminary energy balance appears to be consistent with the proposed picture of the phenomena occurring in the foreshock region

  12. Impact of helium implantation and ion-induced damage on reflectivity of molybdenum mirrors

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Carrasco, A., E-mail: alvarogc@kth.se [Department of Fusion Plasma Physics, Royal Institute of Technology (KTH), Teknikringen 31, 100 44 Stockholm (Sweden); Petersson, P.; Hallén, A. [Department of Fusion Plasma Physics, Royal Institute of Technology (KTH), Teknikringen 31, 100 44 Stockholm (Sweden); Grzonka, J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, 02-507 Warsaw (Poland); Institute of Electronic Materials Technology, 133 Wolczynska Str., 01-919 Warsaw (Poland); Gilbert, M.R. [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom); Fortuna-Zalesna, E. [Faculty of Materials Science and Engineering, Warsaw University of Technology, 02-507 Warsaw (Poland); Rubel, M. [Department of Fusion Plasma Physics, Royal Institute of Technology (KTH), Teknikringen 31, 100 44 Stockholm (Sweden)

    2016-09-01

    Molybdenum mirrors were irradiated with Mo and He ions to simulate the effect of neutron irradiation on diagnostic first mirrors in next-generation fusion devices. Up to 30 dpa were produced under molybdenum irradiation leading to a slight decrease of reflectivity in the near infrared range. After 3 × 10{sup 17} cm{sup −2} of helium irradiation, reflectivity decreased by up to 20%. Combined irradiation by helium and molybdenum led to similar effects on reflectivity as irradiation with helium alone. Ion beam analysis showed that only 7% of the implanted helium was retained in the first 40 nm layer of the mirror. The structure of the near-surface layer after irradiation was studied with scanning transmission electron microscopy and the extent and size distribution of helium bubbles was documented. The consequences of ion-induced damage on the performance of diagnostic components are discussed.

  13. An algorithm to calculate secondary sputtering by the reflection of ions in two dimensions

    International Nuclear Information System (INIS)

    Smith, R.; Tagg, M.A.

    1986-01-01

    A method for computing the secondary sputtering of ions reflected from two-dimensional surfaces is described. The surface contour is first approximated by a set of line segments and the displacement of these line segments under ion erosion is determined computationally, by summing the contributions of the primary and reflected fluxes. This method can be used as an alternative to the method of characteristics which is normally used to determine primary ion beam effects. Some simple examples are evaluated. These examples illustrate that primary surface erosion theory is not in itself sufficient to explain the topography which can exist on an ion-eroded surface, particularly close to steep-sided structures. (author)

  14. Detection of interstellar pick-up hydrogen in the solar system

    Science.gov (United States)

    Gloeckler, G.; Geiss, J.; Balsiger, H.; Fisk, L. A.; Galvin, A. B.; Ipavich, F. M.; Ogilvie, K. W.; Von Steiger, R.; Wilken, B.

    1993-01-01

    Interstellar hydrogen ionized primarily by the solar wind has been detected by the Solar Wind Ion Composition Spectrometer instrument on the Ulysses spacecraft at a distance of 4.8 AUs from the sun. This 'pick-up' hydrogen is identified by its distinct velocity distribution function, which drops abruptly at twice the local solar wind speed. From the measured fluxes of pick-up protons and singly charged helium, the number densities of neutral hydrogen and helium in the distant regions of the solar system are estimated to be 0.077 +/- 0.015 and 0.013 +/- 0.003 per cu cm, respectively.

  15. Theoretical calculations of the self-reflection coefficients for some species of ions

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Z.M. E-mail: luozm@scu.edu.cn; Gou, C.; Hou, Q

    2002-06-01

    The bipartition model of ion transport has been applied to study the self-reflection coefficients of some species of ion beams which are normally incident to a surface. The computational results has been compared with the results taken from Eckstein and Biersack and the compilation data given by Thomas, Janev and Smith. It was found that there are in reasonable agreement between the results given by the bipartition model and the results given by Monte Carlo method.

  16. Reflectance spectroscopy of PMMA implanted with 50 keV silicon ions

    Energy Technology Data Exchange (ETDEWEB)

    Florian, Bojana [Bulgarian Institute of Metrology, 2 Prof. P. Mutafchiev Str., 1797 Sofia (Bulgaria); Stefanov, Ivan [Department of Quantum Electronics, Faculty of Physics, Sofia University, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria); Hadjichristov, Georgi [Institute of Solid State Physics, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria)

    2009-07-01

    Recently, the modification of the specular reflectivity of PMMA implanted with low-energy (50 keV) silicon ions was studied and nano-clusters formed in PMMA by Si{sup +} implantation were evidenced by Raman spectroscopy and electrical measurements. Further, the optical loss due to off-specular (diffuse) reflectivity of this ion-implanted polymer is also of practical interest for applications such as micro-optical lenses, diffraction gratings, Fresnel lenses, waveguides, etc. We examined both specular and diffuse reflectivity of Si{sup +} implanted PMMA in the UV-Vis-NIR. The effect from Si{sup +} implantation in the dose range 10{sup 14}-10{sup 17} ions/cm{sup 2} is linked to the structure formed in PMMA where the buried ion-implanted layer has a thickness up to 100 nm. As compared to the pristine PMMA, an enhancement of the reflectivity of Si{sup +} implanted PMMA is observed, that is attributed to the modification of the subsurface region of PMMA upon the ion implantation.

  17. Characteristics of the magnetic wall reflection model on ion acceleration in gas-puff z pinch

    International Nuclear Information System (INIS)

    Nishio, M.; Takasugi, K.

    2013-01-01

    The magnetic wall reflection model was examined with the numerical simulation of the trajectory calculation of particles. This model is for the ions accelerated by some current-independent mechanism. The trajectory calculation showed angle dependency of highest velocities of accelerated particles. This characteristics is of the magnetic wall reflection model, not of the other current-independent acceleration mechanism. Thomson parabola measurements of accelerated ions produced in the gas-puff z-pinch experiments were carried out for the verification of the angle dependency. (author)

  18. On the effect of a tangential discontinuity on ions specularly reflected at an oblique shock

    International Nuclear Information System (INIS)

    Burgess, D.

    1989-01-01

    In seeking to explain the events observed close to the Earth's bow shock known as hot, diamagnetic cavities (HDC), or active current sheets (ACS), attention has focused on the microphysics of the interaction of a magnetic field directional discontinuity and a collisionless, supercritical shock. Here the author investigates the case of a tangential discontinuity (TD) convecting into a shock at some arbitrary angle. As a first stage he adopted an approach in which test particles represent ions specularly reflected at the shock front. Widely different behavior is possible depending on the sense of ion gyration relative to the TD. Particles can be injected into the plane of the TD so that they travel upstream trapped close to the TD. This implies that ACS events, presumed to be the result of the interaction of the solar wind with a large density reflected component, are detached from the bow shock. For other geometries, ions interact with the TD but stay close to the shock, implying that ACS events are modifications of the shock. The TD can deprive a limited spatial region of a downstream reflected gyrating ion population (necessary for the quasi-perpendicular supercritical shock to be steady), and so he could anticipate where the shock will not be in equilibrium, and consequently where strong reflection may occur. The detailed behavior of the shock in such a situation must be investigated with self-consistent simulations

  19. Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

    Science.gov (United States)

    Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

    2017-11-01

    The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

  20. Energy reflection coefficient for H+ ions at energies between 10 and 80 keV

    International Nuclear Information System (INIS)

    Chen, C.K.; Bohdansky, J.; Eckstein, W.; Robinson, M.T.

    1984-04-01

    The energy reflection coefficient for H + ions at energies between 10 keV and 80 keV was determined by experiments and by computer calculations. Measurements were made with graphite, Al, Cu, Mo and W. targets. The angle of ion incidence was restricted to 85 0 , 78 0 and 70 0 measured from the surface normal. Calculated data were obtained by two different Monte Carlo computer programs (MARLOWE, TRIM). It was found that both the calculated and the measured data scale with the parameter epsilon cos 2 α, where epsilon is Lindhard's reduced energy and α the angle of incidence for the ions. The measured values are smaller than those calculated. This can be explained by surface roughness which developed during the ion irradiation

  1. New light on ion channel imaging by total internal reflection fluorescence (TIRF) microscopy.

    Science.gov (United States)

    Yamamura, Hisao; Suzuki, Yoshiaki; Imaizumi, Yuji

    2015-05-01

    Ion channels play pivotal roles in a wide variety of cellular functions; therefore, their physiological characteristics, pharmacological responses, and molecular structures have been extensively investigated. However, the mobility of an ion channel itself in the cell membrane has not been examined in as much detail. A total internal reflection fluorescence (TIRF) microscope allows fluorophores to be imaged in a restricted region within an evanescent field of less than 200 nm from the interface of the coverslip and plasma membrane in living cells. Thus the TIRF microscope is useful for selectively visualizing the plasmalemmal surface and subplasmalemmal zone. In this review, we focused on a single-molecule analysis of the dynamic movement of ion channels in the plasma membrane using TIRF microscopy. We also described two single-molecule imaging techniques under TIRF microscopy: fluorescence resonance energy transfer (FRET) for the identification of molecules that interact with ion channels, and subunit counting for the determination of subunit stoichiometry in a functional channel. TIRF imaging can also be used to analyze spatiotemporal Ca(2+) events in the subplasmalemma. Single-molecule analyses of ion channels and localized Ca(2+) signals based on TIRF imaging provide beneficial pharmacological and physiological information concerning the functions of ion channels. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  2. Secondary electron/reflected particle coincidence studies during slow highly charged ion-surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, C.T.; Szilagyi, Z.; Shah, M.B.; McCullough, R.W. [Queen' s Univ., Belfast, Northern Ireland (United Kingdom); Woolsey, J.M. [Stirling Univ. (United Kingdom). DBMS; Trassl, R.; Salzborn, E. [Giessen Univ. (Germany). Inst. fuer Kernphysik

    2001-07-01

    We have measured the secondary electron emission statistics (ES) for 5 keV N{sup q+} (q = 1-4) ions incident at 10 on polycrystalline aluminium, in coincidence with specularly reflected N{sup 0}. In this arrangement the kinetic contribution to secondary electron emission is minimised. The experimental data shows that the coincident electron yield, {gamma}, increases linearly with incident ion charge state. The kinetic emission contribution has also been determined from this data. The ES due to 2 and 4 keV He{sup 2+} impact on polycrystalline aluminium in coincidence with specularly reflected He{sup +} and He{sup 0} have also been determined. The process He{sup 2+} {yields} He{sup 0} yields a larger {gamma} value than the process He{sup 2+} {yields} He{sup +}. (orig.)

  3. Acoustic emission pickup essentially for waveguide

    International Nuclear Information System (INIS)

    Asty, Michel; Saglio, Robert.

    1979-01-01

    Lambda wave length acoustic emission pickup comprising two juxtaposed piezoelectric capsules of equal lambda/2 thickness and with opposite polarization, separated by an electrically insulating foil, the two opposite sides of the capsules being earthed. The electric signal resulting from the acoustic emission is picked up on the two sides facing both sides of the insulating foil and the assembly of the two piezoelectric capsules is mounted on a base insulating it from the structure on which the acoustic emission is being listened to. Application of this pickup to the surveillance of defects in the steel vessels of nuclear reactors, characterized in that it is placed at the end of a metal ultrasonic wave guide the other end of which is welded directly to the vessel [fr

  4. Simulation of ion reflection from a single crystal at grazing angles

    International Nuclear Information System (INIS)

    Karpuzov, D.S.; Armour, D.G.; Evdoimov, I.N.

    1979-01-01

    Features of ion scattering for small angles of incidence, up to about 10 0 from the surface, have been examined for 6 keV Ar + ions in a plane of incidence parallel to the direction in the nickel (110) surface. Ions scattered between the surface layer atoms, either above the surface, or slightly below the surface in the semi-channel make a significant contribution to the reflected beam. The angular dependence of experimentally measured energy spectra can be explained when these scattering events are taken into account. In this region of small elastic energy loss and long path lengths close to the surface, inelastic energy losses assume an important role in determining the energy distribution of the scattered particles. (author)

  5. Temperature effects on the pickup process of water group and hydrogen ions - Extensions of 'A theory for low-frequency waves observed at Comet Giacobini-Zinner' by M. L. Goldstein and H. K. Wong

    Science.gov (United States)

    Brinca, Armando L.; Tsurutani, Bruce T.

    1988-01-01

    Cometary heavy ions can resonantly excite hydromagnetic wave activity with spacecraft frequency spectra strongly deviating from the ion cyclotron frequency. The influence of the newborn particle temperature on this effect is assessed, its relevance to the interpretation of the observations is discussed, and an alternative, more efficient mechanism to generate spacecraft frequencies of the order of the proton cyclotron frequency is suggested.

  6. Electromagnetically-induced nuclear-charge pickup observed in ultra-relativistic Pb collisions

    International Nuclear Information System (INIS)

    Scheidenberger, C.; Aumann, T.; Pshenichnov, I.A.; Russian Academy of Sciences, Moscow

    2002-01-01

    A strong increase of inclusive nuclear-charge pickup cross sections, forming 83 Bi from 158 A GeV 82 Pb ions, is observed in comparison to similar measurements at 10.6 A GeV. From the dependence of these cross sections on target atomic number, this increase is attributed to the electromagnetic process of pion production by equivalent photons. The observed cross sections can be reproduced quantitatively using the recently developed RELDIS code. (orig.)

  7. Analytical model of tilted driver–pickup coils for eddy current nondestructive evaluation

    Science.gov (United States)

    Cao, Bing-Hua; Li, Chao; Fan, Meng-Bao; Ye, Bo; Tian, Gui-Yun

    2018-03-01

    A driver-pickup probe possesses better sensitivity and flexibility due to individual optimization of a coil. It is frequently observed in an eddy current (EC) array probe. In this work, a tilted non-coaxial driver-pickup probe above a multilayered conducting plate is analytically modeled with spatial transformation for eddy current nondestructive evaluation. Basically, the core of the formulation is to obtain the projection of magnetic vector potential (MVP) from the driver coil onto the vector along the tilted pickup coil, which is divided into two key steps. The first step is to make a projection of MVP along the pickup coil onto a horizontal plane, and the second one is to build the relationship between the projected MVP and the MVP along the driver coil. Afterwards, an analytical model for the case of a layered plate is established with the reflection and transmission theory of electromagnetic fields. The calculated values from the resulting model indicate good agreement with those from the finite element model (FEM) and experiments, which validates the developed analytical model. Project supported by the National Natural Science Foundation of China (Grant Nos. 61701500, 51677187, and 51465024).

  8. Reflection of the solar wind ions at the earth's bow shock: energization

    International Nuclear Information System (INIS)

    Bonifazi, C.; Moreno, G.; Russell, C.T.

    1983-01-01

    The energies of the field-aligned proton beams observed upstream of the earth's bow shock are tested, on a statistical basis, against a simple reflection model. The comparison is carried out using both plasma and magnetic field data collected by the ISEE 2 spacecraft. The observations refer to the period from November 5 to December 20, 1977. According to this model, some of the solar wind protons incident upon the earth's shock front when reflected upstream gain energy by displacement parallel to the interplanetary electric field. The energy gained in the reflection can be described as a function of the angles between the interplanetary magnetic field, the solar wind bulk velocity, and the local shock normal. The task of finding these angles, i.e., the expected source point of the reflected ions at the earth's shock front, has been resolved using both the measured magnetic field direction and actual beam trajectory. The latter method, which takes into account the ion drift velocity, leads to a better agreement between theory and observations when far from the shock. In particular, it allows us to check the energies of the field-aligned beams even when they are observed far from the earth's bow shock (at distances up to 10-15 R/sub E/). We confirm, on a statistical basis, the test of the model recently carried out using the Los Alamos National Laboratory/Max-Planck-extraterrestrische observations on ISEE 1 and 2. We infer that reflected beams can sometimes propagate far upstream of the earth's bow shock without changing their energy properties

  9. A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Y., E-mail: yito@riken.jp [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Schury, P. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States); Wada, M.; Naimi, S. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Smorra, C. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Sonoda, T. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mita, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Takamine, A. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoyama Gakuin University, 4-4-25 Shibuya, Shibuya-ku, Tokyo 150-8366 (Japan); Okada, K. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Ozawa, A. [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Wollnik, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States)

    2013-12-15

    Highlights: • Fast cooling time: 2 ms. • High efficiency: ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +}. • 100% Duty cycle with double trap system. -- Abstract: A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +} has been achieved.

  10. A study of charge-pickup interactions by (158A GeV) Pb nuclei

    International Nuclear Information System (INIS)

    Sher, G.; Shahzad, M.I.

    2012-01-01

    Study of the relativistic heavy-ion collision is important to focus on probing phase transitions between hadrons and quark-gluon phases in the extreme conditions of temperature and density of nuclear matter formed in the collisions. These states of nuclear matter are expected to be created in relativistic nuclear collisions with large overlap of interacting nuclei, the Lorentz-boosted Coulomb potential Vc proportional to alpha gamma Z/b of a partner with charge Z is very strong, where b is impact parameter and is the fine structure constant. Either one or both nuclei may be disintegrated by the electromagnetic forces in ultra-peripheral collisions at b = R1 + R2, where R1 and R2 are the nuclear radii. This distinct feature of electromagnetic dissociation makes it possible to study the behavior of nuclear matter under electromagnetic fields. The nuclear charge-pickup ( delta Z = +1) by Pb projectiles at energy 158A GeV interacting with targets Bi, Pb, Cu and Al was investigated using CR39 nuclear track detectors. The target-detector stacks were exposed at CERN SPS beam facility. The projectile and fragments charge states have been identified using the etch-cone lengths for charge-pickup at Z = 83 of residual nuclei. Our measured charge-pickup cross sections (delta Z = +1) are shown. It was observed that for the heavy targets the increase in the cross section is anticipated by substantial contribution of electromagnetic dissociation process of production by virtual photons which is almost negligible at 10.6A GeV. In the light target region, our measured cross sections and charge-pickup cross sections reported at energy 10.6A GeV show dominant nuclear contribution and very small contribution of electromagnetic dissociation term. A strong dependence of charge-pickup cross sections on the target mass number was observed particularly in the heavy targets. (orig./A.B.)

  11. Naturalistic drive cycle synthesis for pickup trucks.

    Science.gov (United States)

    Liu, Zifan; Ivanco, Andrej; Filipi, Zoran

    2015-09-01

    Future pick-up trucks are meeting much stricter fuel economy and exhaust emission standards. Design tradeoffs will have to be carefully evaluated to satisfy consumer expectations within the regulatory and cost constraints. Boundary conditions will obviously be critical for decision making: thus, the understanding of how customers are driving in naturalistic settings is indispensable. Federal driving schedules, while critical for certification, do not capture the richness of naturalistic cycles, particularly the aggressive maneuvers that often shape consumer perception of performance. While there are databases with large number of drive cycles, applying all of them directly in the design process is impractical. Therefore, representative drive cycles that capture the essence of the naturalistic driving should be synthesized from naturalistic driving data. Naturalistic drive cycles are firstly categorized by investigating their micro-trip components, defined as driving activities between successive stops. Micro-trips are expected to characterize underlying local traffic conditions, and separate different driving patterns. Next, the transitions from one vehicle state to another vehicle state in each cycle category are captured with Transition Probability Matrix (TPM). Candidate drive cycles can subsequently be synthesized using Markov Chain based on TPMs for each category. Finally, representative synthetic drive cycles are selected through assessment of significant cycle metrics to identify the ones with smallest errors. This paper provides a framework for synthesis of representative drive cycles from naturalistic driving data, which can subsequently be used for efficient optimization of design or control of pick-up truck powertrains. Manufacturers will benefit from representative drive cycles in several aspects, including quick assessments of vehicle performance and energy consumption in simulations, component sizing and design, optimization of control strategies, and

  12. Reflection and self-sputtering of nickel at oblique angles of ion incidence

    International Nuclear Information System (INIS)

    Hechtl, E.; Eckstein, W.; Roth, J.

    1994-01-01

    Measurement of the erosion yield of a target under ion bombardment using the weight change determines the sum of the sputtering yield and the particle reflection coefficient. The different erosion behavior of a volatile (Kr) and a nonvolatile projectile (Ni) are investigated on a nickel target in the energy range from 60 eV to 10 keV at an incidence angle of 75 . The angular dependence of the erosion yield is studied for 100, 500, and 2500 eV. In comparison with Monte Carlo calculations using the TRIM.SP program it is shown that at low energies ( 1 keV). (orig.)

  13. Vehicle test report: Battronic pickup truck

    Science.gov (United States)

    Price, T. W.; Shain, T. W.; Freeman, R. J.; Pompa, M. F.

    1982-01-01

    An electric pickup truck was tested to characterize certain parameters and to provide baseline data that can be used for the comparison of improved batteries that may be incorporated into the vehicle at a later time. The vehicle tests were concentrated on the electrical drive subsystem; i.e., the batteries, controller, and motor. The tests included coastdowns to characterize the road load and range evaluations for both cyclic and constant speed conditions. A qualitative evaluation of the vehicle's performance was made by comparing its constant speed range performance with other vehicles.

  14. Ford F250 Dedicated CNG Pickup

    International Nuclear Information System (INIS)

    Eudy, Leslie

    1999-01-01

    The U.S. Department of Energy (DOE) is encouraging the use of alternative fuels and alternative fuel vehicles (AFVs). To support this activity, DOE has directed the National Renewable Energy Laboratory (NREL) to conduct projects to evaluate the performance and acceptability of light-duty AFVs. In this study, we tested a pair of 1998 Ford F-250 pickups: one dedicated compressed natural gas (CNG) model and a gasoline model as closely matched as possible. Each vehicle was run through a series of tests to evaluate acceleration, fuel economy, braking, and cold-start capabilities, as well as more subjective performance indicators such as handling, climate control, and noise

  15. Position pickup of the PS Booster

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The beam position around the 4 rings of the PS Booster (originally 800 MeV, now 1.4 GeV), is measured with electrostatic pickups (PU). They consist of a ceramic cylinder forming part of the vacuum chamber, and, in order to save space, they are located inside the multipole lenses. The inside of the ceramic is coated with a metallic layer, into which the form of the electrodes was cut by computer-controlled micro-sandblasting. Each PU has a pair of horizontal and a pair of vertical electrodes, as well as a separate intensity-sensing circular electrode.

  16. Characterization of BPM pickup designs for the HESR rate at FAIR using simulations and numerical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Halama, Arthur; Kamerdzhiev, Vsevolod; Boehme, Christian; Srinivasan, Sudharsan [Forschungszentrum Juelich, IKP-4 (Germany)

    2016-07-01

    The institute of Nuclear Physics 4(IKP-4) of the Research Center Juelich (FZJ) is in charge of building and commissioning the High Energy Storage Ring (HESR) within the international Facility for Antiproton and Ion Research (FAIR) at Darmstadt. Simulations and numerical calculations were performed to characterize the initial beam position pickup design. Capacitive couplings of the electrodes and the behavior of the electrical equivalent circuit were investigated. This made room for changes to the design and performance increase. A prototype of the BPM pickup was constructed and tested on a dedicated test bench. Preliminary results will be presented. In order to gain higher signal levels and higher sensitivity, another suggested design was characterized as well and put into comparison.

  17. Energy Reflection Coefficients for 5-10 keV He Ions Incident on Au, Ag, and Cu

    DEFF Research Database (Denmark)

    Schou, Jørgen; Sørensen, H.; Littmark, U.

    1978-01-01

    The calorimetric deuterium-film method was used for measurements of the energy reflection coefficient γ for normal incidence of 5-10 keV He ions on Cu, Ag and Au. A theoretical calculation of γ by means of transport theory gives fair agreement with the experimental results. The experimental data...... the experimental and theoretical results for the He ions are in acceptable agreement with other experimental and theoretical results. For He ions, the experimental γ-values are 20-30% above the values for hydrogen ions for the same value of ε...

  18. Rapid determination of ions by combined solid-phase extraction--diffuse reflectance spectroscopy

    Science.gov (United States)

    Fritz, James S.; Arena, Matteo P.; Steiner, Steven A.; Porter, Marc D.

    2003-01-01

    We introduce colorimetric solid-phase extraction (C-SPE) for the rapid determination of selected ions. This new technique links the exhaustive concentration of an analyte by SPE onto a membrane disk surface for quantitative measurement with a hand-held diffuse reflectance spectrometer. The concentration/measurement procedure is complete in approximately 1 min and can be performed almost anywhere. This method has been used to monitor iodine and iodide in spacecraft water in the 0.1-5.0 ppm range and silver(I) in the range of 5.0-1000 microg/l. Applications to the trace analysis of copper(II), nickel(II), iron(III) and chromium(VI) are described. Studies on the mechanism of extraction showed that impregnation of the disk with a surfactant as well as a complexing reagent results in uptake of additional water, which markedly improves the extraction efficiency.

  19. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  20. Metal ions diffusion through polymeric matrices: A total reflection X-ray fluorescence study

    International Nuclear Information System (INIS)

    Boeykens, S.; Caracciolo, N.; D'Angelo, M.V.; Vazquez, C.

    2006-01-01

    This work proposes the use of X-ray fluorescence with total reflection geometry to explore the metal ions transport in aqueous hydrophilic polymer solutions. It is centered in the study of polymer concentration influence on ion diffusion. This subject is relevant to various and diverse applications, such as drug controlled release, microbiologic corrosion protection and enhanced oil recovery. It is anticipated that diffusion is influenced by various factors in these systems, including those specific to the diffusing species, such as charge, shape, molecular size, and those related to the structural complexity of the matrix as well as any specific interaction between the diffusing species and the matrix. The diffusion of nitrate salts of Ba and Mn (same charge, different hydrodynamic radii) through water-swollen polymeric solutions and gels in the 0.01% to 1% concentration ranges was investigated. The measurements of the metal concentration were performed by TXRF analysis using the scattered radiation by the sample as internal standard. Results are discussed according to different physical models for solute diffusion in polymeric solutions

  1. Slot-type pickup/kicker for AA stochastic cooling

    CERN Multimedia

    1979-01-01

    A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning, in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. View down the centre of a pickup or kicker. See also 7906189, 7906190, 7906583.

  2. Musical instrument recordings made with a fiber Fabry-Perot cavity: photonic guitar pickup.

    Science.gov (United States)

    Ballard, Nicholas; Paz-Soldan, Daniel; Kung, Peter; Loock, Hans-Peter

    2010-04-10

    A 1 cm long, low-finesse fiber-optic cavity was used as a transducer for the vibrations of the soundboard of an acoustic guitar and of a violin. The reflected light is detected and then amplified and recorded using conventional audio instrumentation. The fiber-optic pickup is found to have a high response range in both amplitude (up to 100 microm displacement) and audio frequency (DC to 20 kHz) and good linearity up to a displacement of 225 microm. The audio noise is found to arise from the fiber-optic cables and, to a lesser extent, from the laser and laser driver.

  3. Kaguya observations of the lunar wake in the terrestrial foreshock: Surface potential change by bow-shock reflected ions

    Science.gov (United States)

    Nishino, Masaki N.; Harada, Yuki; Saito, Yoshifumi; Tsunakawa, Hideo; Takahashi, Futoshi; Yokota, Shoichiro; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

    2017-09-01

    There forms a tenuous region called the wake behind the Moon in the solar wind, and plasma entry/refilling into the wake is a fundamental problem of the lunar plasma science. High-energy ions and electrons in the foreshock of the Earth's magnetosphere were detected at the lunar surface in the Apollo era, but their effects on the lunar night-side environment have never been studied. Here we show the first observation of bow-shock reflected protons by Kaguya (SELENE) spacecraft in orbit around the Moon, confirming that solar wind plasma reflected at the terrestrial bow shock can easily access the deepest lunar wake when the Moon stays in the foreshock (We name this mechanism 'type-3 entry'). In a continuous type-3 event, low-energy electron beams from the lunar night-side surface are not obvious even though the spacecraft location is magnetically connected to the lunar surface. On the other hand, in an intermittent type-3 entry event, the kinetic energy of upward-going field-aligned electron beams decreases from ∼ 80 eV to ∼ 20 eV or electron beams disappear as the bow-shock reflected ions come accompanied by enhanced downward electrons. According to theoretical treatment based on electric current balance at the lunar surface including secondary electron emission by incident electron and ion impact, we deduce that incident ions would be accompanied by a few to several times higher flux of an incident electron flux, which well fits observed downward fluxes. We conclude that impact by the bow-shock reflected ions and electrons raises the electrostatic potential of the lunar night-side surface.

  4. Ranges, Reflection and Secondary Electron Emission for keV Hydrogen Ions Incident on Solid N2

    DEFF Research Database (Denmark)

    Børgesen, P.; Sørensen, H.; Hao-Ming, Chen

    1983-01-01

    Ranges were measured for 0.67–3.3 keV/amu hydrogen and deuterium ions in solid N2. Comparisons with similar results for N2-gas confirm the previously observed large phase effect in the stopping cross section. Measurements of the secondary electron emission coefficient for bulk solid N2 bombarded...... by 0.67–9 keV/amu ions also seem to support such a phase effect. It is argued that we may also extract information about the charge state of reflected projectiles....

  5. Reflections of ions in electrostatic analyzers: A case study with New Horizons/Solar Wind Around Pluto

    International Nuclear Information System (INIS)

    Randol, B. M.; Ebert, R. W.; Allegrini, F.; McComas, D. J.; Schwadron, N. A.

    2010-01-01

    Electrostatic analyzers (ESAs), in various forms, are used to measure plasma in a range of applications. In this article, we describe how ions reflect from the interior surfaces of an ESA, the detection of which constitutes a fundamentally nonideal response of ESAs. We demonstrate this effect by comparing laboratory data from a real ESA-based space instrument, the Solar Wind Around Pluto (SWAP) instrument, aboard the NASA New Horizons spacecraft, to results from a model based on quantum mechanical simulations of particles reflected from the instrument's surfaces combined with simulations of particle trajectories through the instrument's applied electrostatic fields. Thus, we show, for the first time, how reflected ions in ESAs lead to nonideal effects that have important implications for understanding the data returned by these instruments, as well as for designing new low-background ESA-based instruments. Specifically, we show that the response of SWAP widens considerably below a level of 10 -3 of the peak response. Thus, a direct measurement of a plasma distribution with SWAP will have an energy-dependent background on the order of ≤10 -3 of the peak of the signal due to that distribution. We predict that this order of magnitude estimate for the background applies to a large number of ESA-based instruments because ESAs operate using a common principle. However, the exact shape of the energy-dependent response will be different for different instruments. The principle of operation is that ions outside the ideal range of energy-per-charge are deflected into the walls of the ESA. Therefore, we propose that a new design paradigm is necessary to mitigate the effect of ion reflections and thus accurately and directly measure the energy spectrum of a plasma using ESAs. In this article, we build a framework for minimizing the effect of ion reflections in the design of new ESAs. Through the use of existing computer simulation software, a design team can use our method

  6. Interaction of a finite-length ion beam with a background plasma: Reflected ions at the quasi-parallel bow shock

    International Nuclear Information System (INIS)

    Onsager, T.G.; Winske, D.; Thomsen, M.F.

    1991-01-01

    The coupling of a finite-length, field-aligned, ion beam with a uniform background plasma is investigated using one-dimensional hybrid computer simulations. The finite-length beam is used to study the interaction between the incident solar wind and ions reflected from the Earth's quasi-parallel bow shock, where the reflection process may vary with time. The coupling between the reflected ions and the solar wind is relevant to ion heating at the bow shock and possibly to the formation of hot, flow anomalies and re-formation of the shock itself. The authors find that although there are many similarities between the instabilities driven by the finite-length beam and those predicted by linear theory for an infinite, homogeneous beam, there are also some important differences. Consistent with linear theory, the waves which dominate the interaction are the electromagnetic right-hand polarized resonant and nonresonant modes. However, in addition to the instability growth rates, the length of time that the waves are in contact with the beam is also an important factor in determining which wave mode will dominate the interaction. Whereas linear theory predicts the nonresonant mode to have the larger growth rate for the parameters they investigate, with finite-length beam they find that both the nonresonant and resonant modes contribute to the interaction. They find that the interaction will result in strong coupling, where a significant fraction of the available free energy is converted into thermal energy in a short time, provided the beam is sufficiently dense or sufficiently long

  7. A gyrokinetic calculation of transmission and reflection of the fast wave in the ion cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Lashmore-Davies, C.N.; Fuchs, V.; Dendy, R.O.

    1993-01-01

    A full-wave equation has been obtained from the gyrokinetic theory for the fast wave traversing a minority cyclotron resonance [Phys. Fluids B 4, 493 (1992)] with the aid of the fast wave approximation [Phys. Fluids 31, 1614 (1988)]. This theory describes the transmission, reflection, and absorption of the fast wave for arbitrary values of the parallel wave number. For oblique propagation the absorption is due to both ion cyclotron damping by minority ions and mode conversion to the ion Bernstein wave. The results for a 3 He minority in a D plasma indicate that for perpendicular propagation and minority temperatures of a few keV the power lost by the fast wave is all mode converted whereas for minority temperatures ∼100 keV∼30% of the incident power is dissipated by the minority ions due to the gyrokinetic correction. The gyrokinetic correction also results in a significant reduction in the reflection coefficient for low field side incidence when k zLB approx-lt 1 and the minority and hybrid resonances overlap

  8. Charge-pickup of 238U at relativistic energies

    International Nuclear Information System (INIS)

    Rubehn, T.; Bassini, R.; Blaich, T.; Imme, G.; Iori, I.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Moehlenkamp, T.; Moretto, L.G.; Ocker, B.; Pochodzalla, J.; Raciti, G.; Schuettauf, A.; Serfling, V.; Trautmann, W.; Trzcinski, A.; Verde, G.; Woerner, A.; Zude, E.; Zwieglinski, B.

    1995-10-01

    Cross sections for the charge-pickup of 238 U projectiles were measured at E/A=600 and 1000 MeV for seven different targets (Be, C, Al, Cu, In, Au and U). Events with two fission fragments with a sum charge of 93 in the exit channel were selected. Due to the significant excitation energy, the dominant part of produced Np nuclei fission instead of decaying to the ground state by evaporation. The observed cross sections can be well reproduced by intranuclear-cascade-plus-evaporation calculations and, therefore, confirm recent results that no exotic processes are needed to explain charge-pickup processes. (orig.)

  9. Observation of Magnetic Waves Excited by Newborn Interstellar Pickup He+ Observed by the Voyager 2 Spacecraft at 30 au

    Energy Technology Data Exchange (ETDEWEB)

    Argall, Matthew R.; Hollick, Sophia J.; Pine, Zackary B., E-mail: Matthew.Argall@unh.edu, E-mail: sjhollick@hotmail.com, E-mail: zbpine@gmail.com [Physics Department and Space Science Center, Morse Hall, University of New Hampshire, Durham, New Hampshire (United States); and others

    2017-11-01

    We report two observations of magnetic waves due to He{sup +} pickup ions observed by the Voyager 2 spacecraft in mid-1989 to demonstrate that such waves occur as far out as ∼30 au from the Sun. The observations are sufficiently far from planets, interplanetary shocks, and other possible sources of energetic particles to make newborn interstellar He{sup +} the only likely explanation for the source of the waves. Additionally, the low-frequency waves that might be expected for a variety of cometary pickup species are not seen. The events studied here were picked from a preliminary list of ∼300 events that were discovered based on polarization signatures in daily spectrograms of the magnetic field between 1977 and 1990. Analysis of those observations is ongoing. We present an analysis of these two observations using the same techniques we have employed for recently reported observations closer to the Sun.

  10. Image potential effect on the specular reflection coefficient of alkali ions scattered from a nickel surface at low energy

    International Nuclear Information System (INIS)

    Zemih, R.; Boudjema, M.; Benazeth, C.; Boudouma, Y.; Chami, A.C.

    2002-01-01

    The resonant charge exchange in the incoming path of alkali ions scattered at low energy from a polycrystalline nickel surface is studied by using the image effect occurring at glancing incidence (2-10 deg. from the surface plane) and for specular reflection. The part of the experimental artefacts (geometrical factor, surface roughness ...) is extracted from the reflection coefficient of almost completely neutralised projectiles (He + or Ne + ) compared with the coefficient obtained from numerical simulations (TRIM and MARLOWE codes). The present model explains very well the lowering of the reflection coefficient measured at grazing incidence (below 4 deg.). Furthermore, the optimised values of the charge fraction in the incoming path and the image potential are in agreement with the theoretical calculations in the case of Na + /Ni at 4 keV

  11. Ion-sound emission by Langmuir soliton reflected at density barrier

    International Nuclear Information System (INIS)

    El-Ashry, M.Y.

    1989-07-01

    The emission of ion-sound waves by an accelerated Langmuir soliton is studied. The acceleration of the soliton is due to an inhomogeneous density barrier. On the assumption that the kinetic energy of the Langmuir soliton is smaller than the potential energy created by the barrier. The basic equations describing the dynamic behaviour of the soliton and the emission of the ion-sound waves are formulated. The qualitative spatial distributions of the perturbed concentration in the ion-sound waves are analyzed at different characteristic points of the soliton. The energy lost by the soliton, as a result of the emission, is estimated. (author). 6 refs, 4 figs

  12. First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

    Science.gov (United States)

    Dickel, T.; Plaß, W. R.; Ayet San Andres, S.; Ebert, J.; Geissel, H.; Haettner, E.; Hornung, C.; Miskun, I.; Pietri, S.; Purushothaman, S.; Reiter, M. P.; Rink, A.-K.; Scheidenberger, C.; Weick, H.; Dendooven, P.; Diwisch, M.; Greiner, F.; Heiße, F.; Knöbel, R.; Lippert, W.; Moore, I. D.; Pohjalainen, I.; Prochazka, A.; Ranjan, M.; Takechi, M.; Winfield, J. S.; Xu, X.

    2015-05-01

    211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

  13. Water cluster fragmentation probed by pickup experiments

    Czech Academy of Sciences Publication Activity Database

    Huang, Ch.; Kresin, V. V.; Pysanenko, Andriy; Fárník, Michal

    2016-01-01

    Roč. 145, č. 10 (2016), s. 104304 ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA15-12386S Institutional support: RVO:61388955 Keywords : Impact ionization * ions * mass spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.965, year: 2016

  14. Bow shock specularly reflected ions in the presence of low-frequency electromagnetic waves: a case study

    Directory of Open Access Journals (Sweden)

    K. Meziane

    2004-07-01

    Full Text Available An energetic ion (E≤40 event observed by the CLUSTER/CIS experiment upstream of the Earth's bow shock is studied in detail. The ion event is observed in association with quasi-monochromatic ULF MHD-like waves, which we show modulate the ion fluxes. According to three statistical bow shock position models, the Cluster spacecrafts are located at ~0.5 Re from the shock and the averaged bow shock θBn0 is about ~30°. The analysis of the three-dimensional angular distribution indicates that ions propagating roughly along the magnetic field direction are observed at the onset of the event. Later on, the angular distribution is gyrophase-bunched and the pitch-angle distribution is peaked at α0~θBn0, consistent with the specular reflection production mechanism. The analysis of the waves shows that they are left-handed in the spacecraft frame of reference (right-handed in the solar wind frame and propagate roughly along the ambient magnetic field; we have found that they are in cyclotron-resonance with the field-aligned beam observed just upstream. Using properties of the waves and particles, we explain the observed particle flux-modulation in the context of θBn changes at the shock caused by the convected ULF waves. We have found that the high count rates coincide with particles leaving the shock when θBn angles are less than ~40°, consistent with the specular reflection hypothesis as the production mechanism of ions.

  15. Slot-type pickup/kicker for AA stochastic cooling

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. See also 7906190, 7906193.

  16. Power, Space and Resistance: Foucauldian Reading of "The Pickup"

    Science.gov (United States)

    Babapi, Nasrin; Parvaneh, Farid

    2015-01-01

    The present article is an attempt to read Nadin Gordimer's "The Pickup" from the lens of Foucault. It starts with Foucault's assumption that power is everything and any kind of relation in the world is defined through the discourses of power. It discusses the techniques through which the power dominates its authority over the subjects…

  17. Analysis of Pick-Up Development in Punching

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2002-01-01

    The development of pick-up of work piece material on the punch surface with increasing number of strokes during punching of stainless steel sheet is investigated applying Scanning Electron Microscopy (SEM), 3D roughness mapping and measurements of the backstroke force. It is found that pick...

  18. Dynamic devices: A primer on pickups and kickers

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, D.A.; Lambertson, G.R.

    1991-11-01

    A charged-particle beam generates electromagnetic fields which in turn interact with the beam's surroundings. These interactions can produce fields which act back on the beam itself, or, if the surroundings'' are of suitably designed form (e.g., sensing electrodes with electrical connection to the outside world''), can provide information on various properties of the beam; such electrodes are generally known as pickups. Similarly, charged- particle beams respond to the presence of externally imposed electromagnetic fields; devices used to generate such fields are generally known as kickers. As we shall show, the behavior of an electrode system when it functions as a pickup is intimately related to its behavior as a kicker. A number of papers on pickup behavior have appeared in recent years in most of which the primary emphasis has been on beam instrumentation; there have also been several workshops on the subject. There have been several papers which have treated both pickup and kicker behavior of a particular electrode system, but this has been done in the context of discussing a specialized application, such as a stochastic cooling system. The approach in the present paper is similar to that of earlier works by one of the authors, which is to provide a unified treatment of pickup and kicker behavior, and, it is hoped, to give the reader an understanding which is both general and fundamental enough to make the above references easily accessible to him. As implied by the revised title, we have done the re-writing with the non-expert in mind. We have made the introduction both lengthier and more detailed, and done the same with much of the explanatory material and discussion.

  19. Dynamic devices: A primer on pickups and kickers

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, D.A.; Lambertson, G.R.

    1991-11-01

    A charged-particle beam generates electromagnetic fields which in turn interact with the beam`s surroundings. These interactions can produce fields which act back on the beam itself, or, if the ``surroundings`` are of suitably designed form (e.g., sensing electrodes with electrical connection to the ``outside world``), can provide information on various properties of the beam; such electrodes are generally known as pickups. Similarly, charged- particle beams respond to the presence of externally imposed electromagnetic fields; devices used to generate such fields are generally known as kickers. As we shall show, the behavior of an electrode system when it functions as a pickup is intimately related to its behavior as a kicker. A number of papers on pickup behavior have appeared in recent years in most of which the primary emphasis has been on beam instrumentation; there have also been several workshops on the subject. There have been several papers which have treated both pickup and kicker behavior of a particular electrode system, but this has been done in the context of discussing a specialized application, such as a stochastic cooling system. The approach in the present paper is similar to that of earlier works by one of the authors, which is to provide a unified treatment of pickup and kicker behavior, and, it is hoped, to give the reader an understanding which is both general and fundamental enough to make the above references easily accessible to him. As implied by the revised title, we have done the re-writing with the non-expert in mind. We have made the introduction both lengthier and more detailed, and done the same with much of the explanatory material and discussion.

  20. Dynamic devices: A primer on pickups and kickers

    International Nuclear Information System (INIS)

    Goldberg, D.A.; Lambertson, G.R.

    1991-11-01

    A charged-particle beam generates electromagnetic fields which in turn interact with the beam's surroundings. These interactions can produce fields which act back on the beam itself, or, if the ''surroundings'' are of suitably designed form (e.g., sensing electrodes with electrical connection to the ''outside world''), can provide information on various properties of the beam; such electrodes are generally known as pickups. Similarly, charged- particle beams respond to the presence of externally imposed electromagnetic fields; devices used to generate such fields are generally known as kickers. As we shall show, the behavior of an electrode system when it functions as a pickup is intimately related to its behavior as a kicker. A number of papers on pickup behavior have appeared in recent years in most of which the primary emphasis has been on beam instrumentation; there have also been several workshops on the subject. There have been several papers which have treated both pickup and kicker behavior of a particular electrode system, but this has been done in the context of discussing a specialized application, such as a stochastic cooling system. The approach in the present paper is similar to that of earlier works by one of the authors, which is to provide a unified treatment of pickup and kicker behavior, and, it is hoped, to give the reader an understanding which is both general and fundamental enough to make the above references easily accessible to him. As implied by the revised title, we have done the re-writing with the non-expert in mind. We have made the introduction both lengthier and more detailed, and done the same with much of the explanatory material and discussion

  1. Ion-bombardment-induced reduction in vacancies and its enhanced effect on conductivity and reflectivity in hafnium nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhiqing; Wang, Jiafu; Hu, Chaoquan; Zhang, Xiaobo; Dang, Jianchen; Gao, Jing; Zheng, Weitao [Jilin University, School of Materials Science and Engineering, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Changchun (China); Zhang, Sam [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Xiaoyi [Chinese Academy of Sciences, Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun (China); Chen, Hong [Jilin University, Department of Control Science and Engineering, Changchun (China)

    2016-08-15

    Although the role of ion bombardment on electrical conductivity and optical reflectivity of transition metal nitrides films was reported previously, the results were controversial and the mechanism was not yet well explored. Here, we show that proper ion bombardment, induced by applying the negative bias voltage (V{sub b}), significantly improves the electrical conductivity and optical reflectivity in rocksalt hafnium nitride films regardless of level of stoichiometry (i.e., in both near-stoichiometric HfN{sub 1.04} and over-stoichiometric HfN{sub 1.17} films). The observed improvement arises from the increase in the concentration of free electrons and the relaxation time as a result of reduction in nitrogen and hafnium vacancies in the films. Furthermore, HfN{sub 1.17} films have always much lower electrical conductivity and infrared reflectance than HfN{sub 1.04} films for a given V{sub b}, owing to more hafnium vacancies because of larger composition deviation from HfN exact stoichiometry (N:Hf = 1:1). These new insights are supported by good agreement between experimental results and theoretical calculations. (orig.)

  2. Comparison of magnetosonic wave and water group ion energy densities at Comet Giacobini-Zinner

    Science.gov (United States)

    Staines, K.; Balogh, A.; Cowley, S. W. H.; Forster, P. M. De F.; Hynds, R. J.; Yates, T. S.; Sanderson, T. R.; Wenzel, K.-P.; Tsurutani, B. T.

    1991-01-01

    Measurements of the Comet Giacobini-Zinner (GZ) are presented to determine to what extent wave-particle scattering redistributed the initial pick-up energy of the ion population. Also examined is the difference between the ion thermal energy and the energy in the magnetic fields of the waves. In spite of uncertainty of about a factor of 2 noted in the pick-up and mass-loaded regions, it is shown that less than approximately 50 percent of the pick-up energy is converted into wave magnetic energy in the inbound pick-up region.

  3. Assessing tether anchor labeling and usability in pickup trucks.

    Science.gov (United States)

    Klinich, Kathleen D; Manary, Miriam A; Malik, Laura A; Flannagan, Carol A; Jermakian, Jessica S

    2018-04-03

    The objective of this study was to investigate vehicle factors associated with child restraint tether use and misuse in pickup trucks and evaluate 4 labeling interventions designed to educate consumers on proper tether use. Volunteer testing was performed with 24 subjects and 4 different pickup trucks. Each subject performed 8 child restraint installations among the 4 pickups using 2 forward-facing restraints: a Britax Marathon G4.1 and an Evenflo Triumph. Vehicles were selected to represent 4 different implementations of tether anchors among pickups: plastic loop routers (Chevrolet Silverado), webbing routers (Ram), back wall anchors (Nissan Frontier), and webbing routers plus metal anchors (Toyota Tundra). Interventions included a diagram label, Quick Response (QR) Code linked to video instruction, coordinating text label, and contrasting text tag. Subjects used the child restraint tether in 93% of trials. However, tether use was completely correct in only 9% of trials. An installation was considered functional if the subject attached the tether to a tether anchor and had a tight installation (ignoring routing and head restraint position); 28% of subjects achieved a functional installation. The most common installation error was attaching the tether hook to the anchor/router directly behind the child restraint (near the top of the seatback) rather than placing the tether through the router and attaching it to the anchor in the adjacent seating position. The Nissan Frontier, with the anchor located on the back wall of the cab, had the highest rate of correct installations but also had the highest rate of attaching the tether to components other than the tether anchor (seat adjustor, child restraint storage hook, around head restraint). None of the labeling interventions had a significant effect on correct installation; not a single subject scanned the QR Code to access the video instruction. Subjects with the most successful installations spent extensive time

  4. In-depth study of in-trap high-resolution mass separation by transversal ion ejection from a multi-reflection time-of-flight device.

    Science.gov (United States)

    Fischer, Paul; Knauer, Stefan; Marx, Gerrit; Schweikhard, Lutz

    2018-01-01

    The recently introduced method of ion separation by transversal ejection of unwanted species in electrostatic ion-beam traps and multi-reflection time-of-flight devices has been further studied in detail. As this separation is performed during the ion storage itself, there is no need for additional external devices such as ion gates or traps for either pre- or postselection of the ions of interest. The ejection of unwanted contaminant ions is performed by appropriate pulses of the potentials of deflector electrodes. These segmented ring electrodes are located off-center in the trap, i.e., between one of the two ion mirrors and the central drift tube, which also serves as a potential lift for capturing incoming ions and axially ejecting ions of interest after their selection. The various parameters affecting the selection effectivity and resolving power are illustrated with tin-cluster measurements, where isotopologue ion species provide mass differences down to a single atomic mass unit at ion masses of several hundred. Symmetric deflection voltages of only 10 V were found sufficient for the transversal ejection of ion species with as few as three deflection pulses. The duty cycle, i.e., the pulse duration with respect to the period of ion revolution, has been varied, resulting in resolving powers of up to several tens of thousands for this selection technique.

  5. Hydrogen pickup and redistribution in alpha-annealed Zircaloy-4

    International Nuclear Information System (INIS)

    Kammenzind, B.F.; Franklin, D.G.; Duffin, W.J.; Peters, H.R.

    1996-01-01

    Zircaloy-4, which is widely used as a core structural material in Pressurized-Water Reactors (PWR), picks up hydrogen during service. Hydrogen solubility in Zircaloy-4 is low and hydrides precipitate after the Zircaloy-4 matrix becomes supersaturated with hydrogen. These hydrides embrittle the Zircaloy-4. To study hydrogen pickup and concentration, a postirradiation nondestructive radiographic technique for measuring hydrogen concentration was developed and qualified. Experiments on hydrogen pickup were conducted in the Advanced Test Reactor (ATR). Ex-reactor tests were conducted to determine the conditions for which hydrogen would dissolve, migrate, and precipitate. Finally, a phenomenological model for hydrogen diffusion was indexed to the data. This presentation describes the equipment and the model, presents the results of experiments, and compares the model predictions to experimental results

  6. Slot-type pickup/kicker for AA stochastic cooling

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    A "slotted transmission line" was used for both pickups and kickers of the cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. Here we see the slotted electrodes partly pulled out of the outer casing. See also 7906189, 7906581X, 7896193.

  7. A model for hydrogen pickup for BWR cladding materials

    International Nuclear Information System (INIS)

    Hede, G.; Kaiser, U.

    2001-01-01

    It has been observed that rod elongation is driven by the hydrogen pickup but not by corrosion as such. Based on this a non-destructive method to determine clad hydrogen concentration has been developed. The method is based on the observation that there are three different mechanisms behind the rod growth: the effect of neutron irradiation on the Zircaloy microstructure, the volume increase of the cladding as an effect of hydride precipitation and axial pellet-cladding-mechanical-interaction (PCMI). The derived correlation is based on the experience of older cladding materials, inspected at hot-cell laboratories, that obtained high hydrogen levels (above 500 ppm) at lower burnup (assembly burnup below 50 MWd/kgU). Now this experience can be applied, by interpolation, on more modern cladding materials with a burnup beyond 50 MWd/kgU by analysis of the rod growth database of the respective cladding materials. Hence, the method enables an interpolation rather than an extrapolation of present day hydrogen pickup database, which improves the reliability and accuracy. Further, one can get a good estimate of the hydrogen pickup during an ongoing outage based on a non-destructive method. Finally, rod growth measurements are normally performed for a large population of rods, hence giving a good statistics compared to examination of a few rods at a hot cell. (author)

  8. Fluororeflectometer for measuring the emission, excitation, reflection and transmission of materials doped with active ions

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Duverger, Aldo S., E-mail: aldo@cifus.uson.mx [Departamento de Física, Universidad de Sonora, Apdo. Postal 5-88, Hermosillo, Sonora 83000, México (Mexico); García-Llamas, Raúl, E-mail: ragal@cifus.uson.mx [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, Hermosillo, Sonora 83000, México (Mexico); Aceves, R., E-mail: raceves@cifus.uson.mx [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, Hermosillo, Sonora 83000, México (Mexico)

    2013-04-15

    The design and construction of a new hybrid instrument, which is named a fluororeflectometer, for measuring the radiation from materials doped with rare earth atoms is presented. This instrument operates in two modes. In the XL-λ mode, the instrument measures the luminescence and excitation spectra of the samples. In the RT-λ mode, the instrument measures the specular reflection and transmission spectra of thick or thin films. A photomultiplier (UV-enhanced photodiode) is used when the XL-λ (RT-λ) mode is in operation. The angle of incidence on the sample and the angle of the detected emission can be changed in both modes; the first one is changed manually and the last one is changed automatically. The reflection and transmission spectra from slabs of KCl:Eu{sup 2+} were measured to test the RT-λ mode. These data were fitted using Lorentz-type dispersion for the material, and the densities for each Eu absorption bands were obtained. In the XL-λ mode, the luminescence and excitation spectra from a slab and thin film of KCl:Eu{sup 2+} were obtained. The sensitivity of the instrument enables the luminescence from thin films with thicknesses as low as 3 μm to be measured; in this case, the signal barely exceeded the noise. The emission spectra from a slab of KCl:Eu{sup 2+} for several angles of incidence were measured in the direction parallel to the interfaces of the slab. -- Highlights: ► Develops an instrument for measuring optical properties of phosphors materials. ► Emission, excitation, transmission and reflectance are measured in KCl:Eu{sup 2+} slabs. ► The angular distribution for the emission, measured in situ, is also characterized. ► Its performance was compared with other instruments and good agreement is found. ► Capabilities are found superior to those offered by commercial fluorometers.

  9. Fluororeflectometer for measuring the emission, excitation, reflection and transmission of materials doped with active ions

    International Nuclear Information System (INIS)

    Ramírez-Duverger, Aldo S.; García-Llamas, Raúl; Aceves, R.

    2013-01-01

    The design and construction of a new hybrid instrument, which is named a fluororeflectometer, for measuring the radiation from materials doped with rare earth atoms is presented. This instrument operates in two modes. In the XL-λ mode, the instrument measures the luminescence and excitation spectra of the samples. In the RT-λ mode, the instrument measures the specular reflection and transmission spectra of thick or thin films. A photomultiplier (UV-enhanced photodiode) is used when the XL-λ (RT-λ) mode is in operation. The angle of incidence on the sample and the angle of the detected emission can be changed in both modes; the first one is changed manually and the last one is changed automatically. The reflection and transmission spectra from slabs of KCl:Eu 2+ were measured to test the RT-λ mode. These data were fitted using Lorentz-type dispersion for the material, and the densities for each Eu absorption bands were obtained. In the XL-λ mode, the luminescence and excitation spectra from a slab and thin film of KCl:Eu 2+ were obtained. The sensitivity of the instrument enables the luminescence from thin films with thicknesses as low as 3 μm to be measured; in this case, the signal barely exceeded the noise. The emission spectra from a slab of KCl:Eu 2+ for several angles of incidence were measured in the direction parallel to the interfaces of the slab. -- Highlights: ► Develops an instrument for measuring optical properties of phosphors materials. ► Emission, excitation, transmission and reflectance are measured in KCl:Eu 2+ slabs. ► The angular distribution for the emission, measured in situ, is also characterized. ► Its performance was compared with other instruments and good agreement is found. ► Capabilities are found superior to those offered by commercial fluorometers

  10. Ion heating and energy partition at the heliospheric termination shock: hybrid simulations and analytical model

    Energy Technology Data Exchange (ETDEWEB)

    Gary, S Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Wu, Pin [BOSTON UNIV.; Schwadron, N A [BOSTON UNIV.; Lee, M [UNIV OF NEW HAMPSHIRE

    2009-01-01

    The Los Alamos hybrid simulation code is used to examine heating and the partition of dissipation energy at the perpendicular heliospheric termination shock in the presence of pickup ions. The simulations are one-dimensional in space but three-dimensional in field and velocity components, and are carried out for a range of values of pickup ion relative density. Results from the simulations show that because the solar wind ions are relatively cold upstream, the temperature of these ions is raised by a relatively larger factor than the temperature of the pickup ions. An analytic model for energy partition is developed on the basis of the Rankine-Hugoniot relations and a polytropic energy equation. The polytropic index {gamma} used in the Rankine-Hugoniot relations is varied to improve agreement between the model and the simulations concerning the fraction of downstream heating in the pickup ions as well as the compression ratio at the shock. When the pickup ion density is less than 20%, the polytropic index is about 5/3, whereas for pickup ion densities greater than 20%, the polytropic index tends toward 2.2, suggesting a fundamental change in the character of the shock, as seen in the simulations, when the pickup ion density is large. The model and the simulations both indicate for the upstream parameters chosen for Voyager 2 conditions that the pickup ion density is about 25% and the pickup ions gain the larger share (approximately 90%) of the downstream thermal pressure, consistent with Voyager 2 observations near the shock.

  11. Cation distribution in spinels and its effect on activity pick-up and passivation behaviour

    International Nuclear Information System (INIS)

    Subramanian, H.; Velmurugan, S.; Narasimhan, S.V.

    2000-01-01

    Spinels are found to be the major corrosion products in the primary heat transport system or nuclear reactors. These corrosion products are activated in the core and are picked up on the deposited corrosion product oxides, which lead to the radiation field buildup on out of core surfaces. In order to mitigate this phenomenon, it is extremely important to understand the structural changes that take place in a spinel in the primary heat transport system. Most of the spinels found in reactor systems are mixed spinels. Cation distribution in tetrahedral and octahedral sites of these spinels, which is temperature dependent, will affect the pickup of active metal ions from solution into these spinels. Distribution of cations in simple spinels was estimated by minimising the Gibbs energy change for the migration of ions between tetrahedral and octahedral sites, based on the assumption that it is the configurational entropy change for the process that dominates the distribution. Cation distribution for mixed spinels was also calculated using the same method. Energy demand for the exchange of an aqueous ion with these spinels has been estimated. (author)

  12. High frequency permeameter with semi-rigid pick-up coil

    International Nuclear Information System (INIS)

    Shin, Sung-Yong; Shin, Kwang-Ho . E-mail : khshin@star.ks.ac.kr; Kim, Jong-sung; Kim, Young-Hak; Lim, Sang-Ho; Sa-gong, Geon

    2006-01-01

    In this study, we propose the application of semi-rigid cable loop as a single turn shielded loop pick-up coil for the high frequency permeameter. Since the semi-rigid cable pick-up coil has simple structure, it is very easy to make the pick-up coil with bending and conventional soldering. The permeability of cobalt base amorphous ribbon was investigated using the developed permeameter for demonstrating its performance. The permeability of the amorphous ribbon was driven from the S-parameters measured using a network analyzer and permameter having the semi-rigid pick-up coil

  13. The pick-up mechanism in composite particle emission processes

    International Nuclear Information System (INIS)

    Zhang Jingshang; Yan Shiwei; Wang Cuilan

    1992-01-01

    The pick-up mechanism has been included in the exciton model for the light composite particle emissions. Based on the cluster phase space integration method the formation probabilities of α,d,t, 3 He are obtained. The calculation results of (n,t) cross sections indicate that this theoretical method can reproduce the experimental data nicely. For triton emissions in pre-equilibrium reaction processes, the semi-direct reactions are the dominant terms which are just omitted in the previous model calculation

  14. Laparoscopic ovum pick-up in spotted paca ( Cuniculus pacas )

    OpenAIRE

    Barros,F.F.P.C.; Teixeira,P.P.M.; Uscategui,R.A.R.; Coutinho,L.N.; Brito,M.B.S.; Kawanami,A.E.; Almeida,V.T.; Mariano,R.S.G.; Nociti,R.P.; Machado,M.R.F.; Vicente,W.R.R.

    2016-01-01

    ABSTRACT The aim of this work is study the laparoscopic ovum pick-up (LapOPU) technique in spotted paca, describing surgery details, complications and oocyte recovery rate. Nine healthy adult non-pregnant captive females were used, in a total of 39 procedures. When the surgical plane of anaesthesia was achieved, the females were positioned at 20º Trendelenburg. Three 6mm trocars were placed on right and left inguinal and hypogastric regions. Abdomen was inflated with CO2 and the intra-abdomin...

  15. Embodied intersubjective engagement in mother-infant tactile communication: a cross-cultural study of Japanese and Scottish mother-infant behaviors during infant pick-up.

    Science.gov (United States)

    Negayama, Koichi; Delafield-Butt, Jonathan T; Momose, Keiko; Ishijima, Konomi; Kawahara, Noriko; Lux, Erin J; Murphy, Andrew; Kaliarntas, Konstantinos

    2015-01-01

    This study examines the early development of cultural differences in a simple, embodied, and intersubjective engagement between mothers putting down, picking up, and carrying their infants between Japan and Scotland. Eleven Japanese and ten Scottish mothers with their 6- and then 9-month-old infants participated. Video and motion analyses were employed to measure motor patterns of the mothers' approach to their infants, as well as their infants' collaborative responses during put-down, pick-up, and carry phases. Japanese and Scottish mothers approached their infants with different styles and their infants responded differently to the short duration of separation during the trial. A greeting-like behavior of the arms and hands was prevalent in the Scottish mothers' approach, but not in the Japanese mothers' approach. Japanese mothers typically kneeled before making the final reach to pick-up their children, giving a closer, apparently gentler final approach of the torso than Scottish mothers, who bent at the waist with larger movements of the torso. Measures of the gap closure between the mothers' hands to their infants' heads revealed variably longer duration and distance gap closures with greater velocity by the Scottish mothers than by the Japanese mothers. Further, the sequence of Japanese mothers' body actions on approach, contact, pick-up, and hold was more coordinated at 6 months than at 9 months. Scottish mothers were generally more variable on approach. Measures of infant participation and expressivity indicate more active participation in the negotiation during the separation and pick-up phases by Scottish infants. Thus, this paper demonstrates a culturally different onset of development of joint attention in pick-up. These differences reflect cultures of everyday interaction.

  16. Embodied intersubjective engagement in mother–infant tactile communication: a cross-cultural study of Japanese and Scottish mother–infant behaviors during infant pick-up

    Science.gov (United States)

    Negayama, Koichi; Delafield-Butt, Jonathan T.; Momose, Keiko; Ishijima, Konomi; Kawahara, Noriko; Lux, Erin J.; Murphy, Andrew; Kaliarntas, Konstantinos

    2015-01-01

    This study examines the early development of cultural differences in a simple, embodied, and intersubjective engagement between mothers putting down, picking up, and carrying their infants between Japan and Scotland. Eleven Japanese and ten Scottish mothers with their 6- and then 9-month-old infants participated. Video and motion analyses were employed to measure motor patterns of the mothers’ approach to their infants, as well as their infants’ collaborative responses during put-down, pick-up, and carry phases. Japanese and Scottish mothers approached their infants with different styles and their infants responded differently to the short duration of separation during the trial. A greeting-like behavior of the arms and hands was prevalent in the Scottish mothers’ approach, but not in the Japanese mothers’ approach. Japanese mothers typically kneeled before making the final reach to pick-up their children, giving a closer, apparently gentler final approach of the torso than Scottish mothers, who bent at the waist with larger movements of the torso. Measures of the gap closure between the mothers’ hands to their infants’ heads revealed variably longer duration and distance gap closures with greater velocity by the Scottish mothers than by the Japanese mothers. Further, the sequence of Japanese mothers’ body actions on approach, contact, pick-up, and hold was more coordinated at 6 months than at 9 months. Scottish mothers were generally more variable on approach. Measures of infant participation and expressivity indicate more active participation in the negotiation during the separation and pick-up phases by Scottish infants. Thus, this paper demonstrates a culturally different onset of development of joint attention in pick-up. These differences reflect cultures of everyday interaction. PMID:25774139

  17. The ATLAS beam pick-up based timing system

    International Nuclear Information System (INIS)

    Ohm, C.; Pauly, T.

    2010-01-01

    The ATLAS BPTX stations are composed of electrostatic button pick-up detectors, located 175 m away along the beam pipe on both sides of ATLAS. The pick-ups are installed as a part of the LHC beam instrumentation and used by ATLAS for timing purposes. The usage of the BPTX signals in ATLAS is twofold: they are used both in the trigger system and for LHC beam monitoring. The BPTX signals are discriminated with a constant-fraction discriminator to provide a Level-1 trigger when a bunch passes through ATLAS. Furthermore, the BPTX detectors are used by a stand-alone monitoring system for the LHC bunches and timing signals. The BPTX monitoring system measures the phase between collisions and clock with a precision better than 100 ps in order to guarantee a stable phase relationship for optimal signal sampling in the sub-detector front-end electronics. In addition to monitoring this phase, the properties of the individual bunches are measured and the structure of the beams is determined. On September 10, 2008, the first LHC beams reached the ATLAS experiment. During this period with beam, the ATLAS BPTX system was used extensively to time in the read-out of the sub-detectors. In this paper, we present the performance of the BPTX system and its measurements of the first LHC beams.

  18. Hi-Vision telecine system using pickup tube

    Science.gov (United States)

    Iijima, Goro

    1992-08-01

    Hi-Vision broadcasting, offering far more lifelike pictures than those produced by existing television broadcasting systems, has enormous potential in both industrial and commercial fields. The dissemination of the Hi-Vision system will enable vivid, movie theater quality pictures to be readily enjoyed in homes in the near future. To convert motion film pictures into Hi-Vision signals, a telecine system is needed. The Hi-Vision telecine systems currently under development are the "laser telecine," "flying-spot telecine," and "Saticon telecine" systems. This paper provides an overview of the pickup tube type Hi-Vision telecine system (referred to herein as the Saticon telecine system) developed and marketed by Ikegami Tsushinki Co., Ltd.

  19. Beam position pickup for antiprotons to the ISR

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The Antiproton Project, launched for proton-antiproton collisions in the SPS (SPS collider), had a side-line for p-pbar collisions in the ISR. A new transfer line, TT6, was constructed to transport antiprotons from the 26 GeV PS to the injection line TT1 of ISR ring 2. Antiprotons were a scarce commodity. For setting up the lines, beam diagnostic devices in the antiproton path had to work reliably and precisely with just a few low-intensity pilot pules: single bunches of about 2x10**9 antiprotons every few hours. Electrostatic pickup electrodes were used to measure beam position. They could be mounted for measurement in the horizontal plane, as in this picture, or at 90 deg, for the vertical plane.

  20. Receivers for processing electron beam pick-up electrode signals

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    There are several methods of determining the transverse position of the electron beam, based upon sensing either the electric field, the magnetic field, or both. At the NSLS the transverse beam position monitors each consist of a set of four circular electrodes. There are 48 sets of pick-up electrodes in the X-ray ring and 24 in the VUV storage ring for determining the electron orbit, and a few extra sets installed for specialized purposes. When the beam passes between the four electrodes, charge is induced on each electrode, the amount depending upon the distance of the beam from that electrode. If V a , V b , V c and V d given by a difference between pairs of electrodes normalized for variations in beam current by dividing by the sum of electrode voltages. The method of processing these signals depends upon their time structure. The electrons circulating around the vacuum chamber are concentrated in short bunches within stability buckets produced by the accelerating voltage in the RF cavities. The charges induced on the pickup electrodes then are narrow pulses, a fraction of a nanosecond long, and would result in a monopolar voltage pulses if it were not for the impedance of the cable connecting the electrode to the processing apparatus. The capacitance between each electrode and the chamber wall is only a few picofarads and is effectively in parallel with the cable impedance (50 ohms). Thus an appreciable amount of the charge flows off the electrode while the bunch is between the electrodes, resulting in potential of opposite sign as the bunch is leaving the vicinity of the electrode. The resulting signal consists of a series of bipolar pulses, each of less than one nanosecond duration

  1. Ion cyclotron emission calculations using a 2D full wave numerical code

    International Nuclear Information System (INIS)

    Batchelor, D.B.; Jaeger, E.F.; Colestock, P.L.

    1987-01-01

    Measurement of radiation in the HF band due to cyclotron emission by energetic ions produced by fusion reactions or neutral beam injection promises to be a useful diagnostic on large devices which are entering the reactor regime of operation. A number of complications make the modelling and interpretation of such measurements difficult using conventional geometrical optics methods. In particular the long wavelength and lack of high directivity of antennas in this frequency regime make observation of a single path across the plasma into a viewing dump impractical. Pickup antennas effectively see the whole plasma and wall reflection effects are important. We have modified our 2D full wave ICRH code 2 to calculate wave fields due to a distribution of energetic ions in tokamak geometry. The radiation is modeled as due to an ensemble of localized source currents distributed in space. The spatial structure of the coherent wave field is then calculated including cyclotron harmonic damping as compared to the usual procedure of incoherently summing powers of individual radiators. This method has the advantage that phase information from localized radiating currents is globally retained so the directivity of the pickup antennas is correctly represented. Also standing waves and wall reflections are automatically included

  2. MgB{sub 2} magnetometer with a directly coupled pick-up loop

    Energy Technology Data Exchange (ETDEWEB)

    Portesi, C [Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, I-10135 Turin (Italy); Mijatovic, D [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Veldhuis, D [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Brinkman, A [Low Temperature Division and Mesa Research Institute, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Monticone, E [Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, I-10135 Turin (Italy); Gonnelli, R S [INFM, Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Turin (Italy)

    2006-05-15

    In this work, we show the results obtained in the fabrication and characterization of an MgB{sub 2} magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which incorporates two nanobridges as weak links in a superconducting loop. The nanobridges were realized by focused ion beam milling; they were 240 nm wide and had a critical current density of 10{sup 7} A cm{sup -2}. The magnetometer was characterized at different temperatures and also measurements of the noise levels have been performed. The device shows Josephson quantum interference up to 20 K and the calculated effective area at low temperatures was 0.24 mm{sup 2}. The transport properties of the magnetometer allow determining fundamental materials properties of the MgB{sub 2} thin films, such as the penetration depth.

  3. MgB2 magnetometer with a directly coupled pick-up loop

    Science.gov (United States)

    Portesi, C.; Mijatovic, D.; Veldhuis, D.; Brinkman, A.; Monticone, E.; Gonnelli, R. S.

    2006-05-01

    In this work, we show the results obtained in the fabrication and characterization of an MgB2 magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which incorporates two nanobridges as weak links in a superconducting loop. The nanobridges were realized by focused ion beam milling; they were 240 nm wide and had a critical current density of 107 A cm-2. The magnetometer was characterized at different temperatures and also measurements of the noise levels have been performed. The device shows Josephson quantum interference up to 20 K and the calculated effective area at low temperatures was 0.24 mm2. The transport properties of the magnetometer allow determining fundamental materials properties of the MgB2 thin films, such as the penetration depth.

  4. PAL-XFEL cavity beam position monitor pick-up design and beam test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sojeong, E-mail: sojung8681@postech.ac.kr; Park, Young Jung; Kim, Changbum; Kim, Seung Hwan; Shin, Dong Cheol; Han, Jang-Hui; Ko, In Soo

    2016-08-11

    As an X-ray Free Electron Laser, PAL-XFEL is about to start beam commissioning. X-band cavity beam position monitor (BPM) is used in the PAL-XFEL undulator beam line. Prototypes of cavity BPM pick-up were designed and fabricated to test the RF characteristics. Also, the beam test of a cavity BPM pick-up was done in the Injector Test Facility (ITF). In the beam test, the raw signal properties of the cavity BPM pick-up were measured at a 200 pC bunch charge. According to the RF test and beam test results, the prototype cavity BPM pick-up design was confirmed to meet the requirements of the PAL-XFEL cavity BPM system.

  5. In-situ electrochemical impedance spectroscopy measurements of zirconium alloy oxide conductivity: Relationship to hydrogen pickup

    International Nuclear Information System (INIS)

    Couet, Adrien; Motta, Arthur T.; Ambard, Antoine; Livigni, Didier

    2017-01-01

    Highlights: • In-situ electrochemistry on zirconium alloys in 360 °C pure water show oxide layer resistivity changes during corrosion. • A linear relationship is observed between oxide resistivity and instantaneous hydrogen pickup fraction. • The resistivity of the oxide layer formed on Zircaloy-4 (and thus its hydrogen pickup fraction) is higher than on Zr-2.5Nb. - Abstract: Hydrogen pickup during nuclear fuel cladding corrosion is a critical life-limiting degradation mechanism for nuclear fuel. Following a program dedicated to zirconium alloys, corrosion, it has been hypothesized that oxide electronic resistivity determines hydrogen pickup. In-situ electrochemical impedance spectroscopy experiments were performed on Zircaloy-4 and Zr-2.5Nb alloys in 360 °C water. The oxide resistivity was measured as function of time. The results show that as the oxide resistivity increases so does the hydrogen pickup fraction. The resistivity of the oxide layer formed on Zircaloy-4 is higher than on Zr-2.5Nb, resulting in a higher hydrogen pickup fraction of Zircaloy-4, compared to Zr-2.5Nb.

  6. Development of a doorframe-typed swinging seedling pick-up device for automatic field transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Han, H.; Mao, H.; Hu, J.; Tian, K.

    2015-07-01

    A doorframe-typed swing seedling pick-up device for automatic field transplanters was developed and evaluated in a laboratory. The device, consisting of a path manipulator and two grippers, can move the pins slowly to extract seedlings from the tray cells and return quickly to the pick-up point for the next extraction. The path manipulator was constructed with the creative design of type-Ⅱ mechanism combination in series. It consists of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism. The gripper is a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction. The dynamic analysis of the designed seedling pick-up device was simulated with ADAMS software. Being the first prototype, various performance tests under local production conditions were conducted to find out the optimal machine operation parameters and transplant production conditions. As the gripper with multiple fine pins was moved by the swing pick-up device, it can effectively complete the transplanting work cycle of extracting, transferring, and discharging a seedling. The laboratory evaluation showed that the pick-up device equipped with two grippers can extract 80 seedlings/min with a 90% success and a 3% failure in discharging seedlings, using 42-day-old tomato plantlets. The quality of extracting seedlings was satisfactory. (Author)

  7. Single neutron pick-up on {sup 104}Pd

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, M.R.D.; Andre, J.P.A.M. de; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L. [Universidade de Sao Paulo, SP (Brazil). Inst. de Fisica; Ukita, G.M. [Universidade de Santo Amaro, SP (Brazil). Faculdade de Psicologia

    2006-12-15

    Low-lying levels of {sup 103}Pd have been investigated through the (d,t) reaction on {sup 104}Pd, at an incident deuteron energy of 15.0 MeV. Outgoing particles were momentum analyzed by an Enge magnetic spectrograph and detected in nuclear emulsion plates, with an energy resolution of 8 keV. Previous (d,t) work suffered from a much worse resolution than that here achieved. A partial analysis of the data obtained is reported, referring to six out of the fourteen scattering angles for which data were obtained. Angular distributions associated with eight of the thirteen levels seen up to 1.1 MeV of excitation have been compared to DWBA one-neutron pick-up predictions. Both, the attributed excitation energy values and the transferred angular momenta are in excellent agreement with the results of other kind of experiments, as tabulated by the Nuclear Data Sheets. Some peculiar structure characteristics, associated with the yrast 5/2{sup +}, 3/2{sup +} and 7/2{sup +} states found in the Ru chain could be recognized also in {sup 103}Pd, pointing to the possibility of a more global understanding of this transitional mass region. (author)

  8. One-nucleon pickup reactions and compound-nuclear decays

    Science.gov (United States)

    Escher, J. E.; Burke, J. T.; Casperson, R. J.; Hughes, R. O.; Scielzo, N. D.

    2018-05-01

    One-nucleon transfer reactions, long used as a tool to study the structure of nuclei, are potentially valuable for determining reaction cross sections indirectly. This is significant, as many reactions of interest to astrophysics and other applications involve short-lived isotopes and cannot be measured directly. We describe a procedure for obtaining constraints for calculations of neutron capture cross sections using observables from experiments with transfer reactions. As a first step toward demonstrating the method, we outline the theory developments used to properly describe the production of the compound nucleus 88Y* via the one-nucleon pickup reaction 89Y(p,d)88Y* and test the description with data from a recent experiment. We indicate how this development can be used to extract the unknown 87Y(n,γ) cross section from 89Y(p,dγ) data. The example illustrates a more generally applicable method for determining unknown cross sections via a combination of theory and transfer (or inelastic scattering) experiments.

  9. Laparoscopic ovarian biopsy pick-up method for goats.

    Science.gov (United States)

    Brandão, Fabiana A S; Alves, Benner G; Alves, Kele A; Souza, Samara S; Silva, Yago P; Freitas, Vicente J F; Teixeira, Dárcio I A; Gastal, Eduardo L

    2018-02-01

    Biopsy pick-up (BPU) has been considered a safe method to harvest ovarian fragments from live animals. However, no studies have been reported on the use of BPU to collect in vivo ovarian tissue in goats. The goals of this study were: (i) to test different biopsy needle sizes to collect ovarian tissue in situ using the BPU method (Experiment 1), and (ii) to study ovarian tissue features such as preantral follicle density, morphology, class distribution, and stromal cell density in ovarian fragments obtained in vivo through a laparoscopic BPU method (Experiment 2). In Experiment 1, goat ovaries (n = 20) were collected in a slaughterhouse and subjected to in situ BPU. Three needles (16, 18, and 20G) were tested. In Experiment 2, the most efficient biopsy needle from Experiment 1 was used to perform laparoscopic BPU in goats (n = 8). In Experiment 1, the recovery rate was greater (P rate). Overall, 2054 preantral follicles were recorded in 5882 histological sections analyzed. Mean preantral follicular density was 28.4 ± 1.3 follicles per cm 2 . The follicular density differed (P rate in goats. Furthermore, this study described for the first time that goat ovarian biopsy fragments have a high heterogeneity in follicular density, morphology, class distribution, and stromal cell density. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Single neutron pick-up on 104Pd

    International Nuclear Information System (INIS)

    Rodrigues, M.R.D.; Andre, J.P.A.M. de; Borello-Lewin, T.; Horodynski-Matsushigue, L.B.; Duarte, J.L.M.; Rodrigues, C.L.; Ukita, G.M.

    2006-01-01

    Low-lying levels of 103 Pd have been investigated through the (d,t) reaction on 104 Pd, at an incident deuteron energy of 15.0 MeV. Outgoing particles were momentum analyzed by an Enge magnetic spectrograph and detected in nuclear emulsion plates, with an energy resolution of 8 keV. Previous (d,t) work suffered from a much worse resolution than that here achieved. A partial analysis of the data obtained is reported, referring to six out of the fourteen scattering angles for which data were obtained. Angular distributions associated with eight of the thirteen levels seen up to 1.1 MeV of excitation have been compared to DWBA one-neutron pick-up predictions. Both, the attributed excitation energy values and the transferred angular momenta are in excellent agreement with the results of other kind of experiments, as tabulated by the Nuclear Data Sheets. Some peculiar structure characteristics, associated with the yrast 5/2 + , 3/2 + and 7/2 + states found in the Ru chain could be recognized also in 103 Pd, pointing to the possibility of a more global understanding of this transitional mass region. (author)

  11. Pick-up and impact of flexible bodies

    Science.gov (United States)

    Singh, H.; Hanna, J. A.

    2017-09-01

    Picking up, laying down, colliding, rolling, and peeling are partial-contact interactions involving moving discontinuities. We examine the balances of momentum and energy across a moving discontinuity in a string, with allowance for injection or dissipation by singular supplies. We split the energy dissipation according to its invariance properties, discuss analogies with systems of particles and connections with the literature on shocks and phase transition fronts in various bodies, and derive a compatibility relation between supplies of momentum and translation-invariant energy. For a moving contact discontinuity between a string and a smooth rigid plane in the presence of gravity, we find a surprising asymmetry between the processes of picking up and laying down, such that steady-state kinks in geometry and associated jumps in tension are not admissible during pick-up. This prediction is consistent with experimental observations. We briefly discuss related problems including the falling folded chain, peeling of an adhesive tape, and the "chain fountain". Our approach is applicable to the study of impact and locomotion, and to systems such as moored floating structures and some musical instruments that feature vibrating string and cable elements interacting with a surface.

  12. A comparative UV-vis-diffuse reflectance study on the location and interaction of cerium ions in Al- and Zr-pillared montmorillonite clays

    International Nuclear Information System (INIS)

    Rao, G. Ranga; Mishra, Braja Gopal

    2005-01-01

    The environment, location and interaction of the Ce 3+ ions in the micropores of Al- and Zr-pillared clays have been studied by UV-vis-diffuse reflectance spectroscopy (UV-vis-DRS). The DRS spectra show that the chemical environment of the Ce 3+ ions in cerium exchanged clay is different from that of the Al- and Zr-pillared clays. The Al-Ce pillared clays (Al-Ce-PM) show four distinct absorption bands at 224, 263, 294 and 342 nm in the UV region which are attributed to 4f → 5d interconfigurational transitions of Ce 3+ ions associated with alumina pillars. The O 2- → Ce 3+ charge transfer band observed at 263 nm for Ce-exchanged and Al-Ce-PM clays is blue shifted by 10 nm for Ce-Zr-pillared clays (Ce-Zr-PM) due to fully hydrated Ce 3+ ions. The Ce 3+ ions are incorporated in the Al- and Zr-pillars possibly as AlCeO 3 and Ce x Zr 1-x O 2 particles upon heat treatment

  13. How do air ions reflect variations in ionising radiation in the lower atmosphere in a boreal forest?

    Directory of Open Access Journals (Sweden)

    X. Chen

    2016-11-01

    Full Text Available Most of the ion production in the atmosphere is attributed to ionising radiation. In the lower atmosphere, ionising radiation consists mainly of the decay emissions of radon and its progeny, gamma radiation of the terrestrial origin as well as photons and elementary particles of cosmic radiation. These types of radiation produce ion pairs via the ionisation of nitrogen and oxygen as well as trace species in the atmosphere, the rate of which is defined as the ionising capacity. Larger air ions are produced out of the initial charge carriers by processes such as clustering or attachment to pre-existing aerosol particles. This study aimed (1 to identify the key factors responsible for the variability in ionising radiation and in the observed air ion concentrations, (2 to reveal the linkage between them and (3 to provide an in-depth analysis into the effects of ionising radiation on air ion formation, based on measurement data collected during 2003–2006 from a boreal forest site in southern Finland. In general, gamma radiation dominated the ion production in the lower atmosphere. Variations in the ionising capacity came from mixing layer dynamics, soil type and moisture content, meteorological conditions, long-distance transportation, snow cover attenuation and precipitation. Slightly similar diurnal patterns to variations in the ionising capacity were observed in air ion concentrations of the cluster size (0.8–1.7 nm in mobility diameters. However, features observed in the 0.8–1 nm ion concentration were in good connection to variations of the ionising capacity. Further, by carefully constraining perturbing variables, a strong dependency of the cluster ion concentration on the ionising capacity was identified, proving the functionality of ionising radiation in air ion production in the lower atmosphere. This relationship, however, was only clearly observed on new particle formation (NPF days, possibly indicating that charges after

  14. Influence of Reactive Ion Etching on THz Transmission and Reflection Properties of NiCr Film Deposited on a Dielectric Substrate

    Directory of Open Access Journals (Sweden)

    Jun Gou

    2015-06-01

    Full Text Available Enhanced terahertz (THz absorption of NiCr film deposited on a dielectric substrate has been proven by applying a reactive ion etching (RIE treatment to the dielectric film. Nano – scale nickel – chromium (NiCr thin films are deposited on RIE treated silicon dioxide (SiO2 dielectric substrates to study the transmission and reflection characteristics. Experimental results suggest that both transmission and reflection of NiCr film are weakened by the RIE treatment. The most significant decrease of transmission is observed in 1 ~ 4 THz while that of reflection occurs in 1.7 ~ 2.5 THz band. The decrease of both transmission and reflection is more significant for NiCr film with higher thickness. The RIE treatment, which induces nano – scale surface structures and increases the effective surface area of NiCr film, enhances the absorption and weakens the transmission and reflection of THz radiation.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.6131

  15. Laparoscopic ovum pick-up in spotted paca ( Cuniculus pacas

    Directory of Open Access Journals (Sweden)

    F.F.P.C. Barros

    2016-08-01

    Full Text Available ABSTRACT The aim of this work is study the laparoscopic ovum pick-up (LapOPU technique in spotted paca, describing surgery details, complications and oocyte recovery rate. Nine healthy adult non-pregnant captive females were used, in a total of 39 procedures. When the surgical plane of anaesthesia was achieved, the females were positioned at 20º Trendelenburg. Three 6mm trocars were placed on right and left inguinal and hypogastric regions. Abdomen was inflated with CO2 and the intra-abdominal pressure was stablished in 10mmHg. Follicular punctures were performed moving the ovaries with atraumatic forceps. For punctures, an 18-gauge 3.5 inch long needle attached to a vacuum system with pressure not exceeding 65mmHg was used. Oocytes were recovered into 50mL centrifuge tubes with media composed of PBS supplemented with 10 IU/mL of heparin and kept at 36°C. R Software was used for statistical analysis. Data normality distribution (Shapiro test and variances homoscedasticity (Bartlett test were tested and descriptive statistics (mean±SD was used to present the results. It was only possible to perform LapOPU in 30 of 39 laparoscopies (76.92%. The surgical total time was 37.34 ± 18.53 minutes. The total number of visualized follicles, aspirated follicles, and retrieved oocytes were 502, 415, and 155, respectively. And the same parameters per animal were: 14.34 ± 12.23, 11.86 ± 10.03, and 4.43 ± 4.69 respectively. Oocyte recovery rate was 32.56 ± 27.32%. In conclusion, caudal positioning of portals with slight triangulation allows good viewing of the abdominal cavity and eases the manipulation of the ovaries. Thus this described LapOPU technique is feasible in spotted paca and easy to perform.

  16. Preparation of composite micro/nano structure on the silicon surface by reactive ion etching: Enhanced anti-reflective and hydrophobic properties

    Science.gov (United States)

    Zeng, Yu; Fan, Xiaoli; Chen, Jiajia; He, Siyu; Yi, Zao; Ye, Xin; Yi, Yougen

    2018-05-01

    A silicon substrate with micro-pyramid structure (black silicon) is prepared by wet chemical etching and then subjected to reactive ion etching (RIE) in the mixed gas condition of SF6, CHF3 and He. We systematically study the impacts of flow rates of SF6, CHF3 and He, the etching pressure and the etching time on the surface morphology and reflectivity through various characterizations. Meanwhile, we explore and obtain the optimal combination of parameters for the preparation of composite structure that match the RIE process based on the basis of micro-pyramid silicon substrate. The composite sample prepared under the optimum parameters exhibits excellent anti-reflective performance, hydrophobic, self-cleaning and anti-corrosive properties. Based on the above characteristics, the composite micro/nano structure can be applied to solar cells, photodetectors, LEDs, outdoor devices and other important fields.

  17. Time resolved reflectivity measurements of the amorphous-to-gamma and gamma-to-alpha phase transitions in ion-implanted Al2O3

    International Nuclear Information System (INIS)

    McCallum, J.C.; Simpson, T.W.; Mitchell, I.V.

    1994-01-01

    Time resolved optical reflectivity (TRR) has been used to measure the growth kinetics associated with the amorphous-to-gamma and gamma-to-alpha phase transitions in ion-beam amorphised c-axis oriented α-Al 2 O 3 . The optical reflectivity technique allows the recrystallisation behaviour to be monitored dynamically during regrowth so that the growth kinetics associated with the two phase transitions can be measured simply and accurately from a relatively small number of samples. The amorphous-to-gamma and gamma-to-alpha phase transitions were studied over the temperature ranges of 670-770 C and 900-1070 C, respectively. The growth kinetics obtained for the two transitions are compared to previous work. ((orig.))

  18. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor

    International Nuclear Information System (INIS)

    Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba

    1981-01-01

    During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container

  19. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba (Commissariat des Sciences Nucleaires, Kinshasa (Zaire). Centre Regional d' Etudes Nucleaires)

    1981-01-01

    During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container.

  20. Three-dimensional magnetic nanoparticle imaging using small field gradient and multiple pickup coils

    Energy Technology Data Exchange (ETDEWEB)

    Sasayama, Teruyoshi, E-mail: sasayama@sc.kyushu-u.ac.jp; Tsujita, Yuya; Morishita, Manabu; Muta, Masahiro; Yoshida, Takashi; Enpuku, Keiji

    2017-04-01

    We propose a magnetic particle imaging (MPI) method based on third harmonic signal detection using a small field gradient and multiple pickup coils. First, we developed a system using two pickup coils and performed three-dimensional detection of two magnetic nanoparticle (MNP) samples, which were spaced 15 mm apart. In the experiments, an excitation field strength of 1.6 mT was used at an operating frequency of 3 kHz. A DC gradient field with a typical value of 0.2 T/m was also used to produce the so-called field-free line. A third harmonic signal generated by the MNP samples was detected using the two pickup coils, and the samples were then mechanically scanned to obtain field maps. The field maps were subsequently analyzed using the nonnegative least squares method to obtain three-dimensional position information for the MNP samples. The results show that the positions of the two MNP samples were estimated with good accuracy, despite the small field gradient used. Further improvement in MPI performance will be achieved by increasing the number of pickup coils used. - Highlights: • 3D magnetic particle imaging system combining field-free line and two pickup coils. • Imaging method based on third harmonic signal detection and small field gradient. • Nonnegative least squares method for 3D magnetic nanoparticle image reconstruction. • High spatial resolution despite use of small field gradient.

  1. Cometary ion instabilities in the solar wind

    Czech Academy of Sciences Publication Activity Database

    Matteini, L.; Schwartz, S. J.; Hellinger, Petr

    2015-01-01

    Roč. 119, Special Is. (2015), s. 3-12 ISSN 0032-0633 R&D Projects: GA ČR GA15-10057S Institutional support: RVO:67985815 Keywords : cometary plasma * hybrid simulations * pick-up ion instabilities Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.942, year: 2015

  2. Formation of conductive and reflective silver nanolayers on plastic films via ion doping and solid–liquid interfacial reduction at ambient temperature

    International Nuclear Information System (INIS)

    Cui, Guanghui; Wu, Dezhen; Zhao, Yuan; Liu, Wei; Wu, Zhanpeng

    2013-01-01

    Conductive and reflective silver layers on both sides of polyimide films have been prepared by doping silver–ammonia ions into the surfaces of polyimide film, and subsequent solid–liquid interfacial reduction, during which double diffusion of silver ions and newly formed silver crystals occurred between the interfaces of polyimide films and the aqueous reducing surroundings. The newly formed silver nanoparticles could migrate and aggregate onto both sides of substrate films, forming continuous and compact silver layers that result in excellent conductivity, i.e. ∼0.6 and 0.5 Ω/sq on the upside and downside surfaces, respectively. The surface reflectivity could be detected up to 80% on the downside and 90% on the upside surface as well. The effects of the silver contents and reducing conditions on the morphologies and properties have been investigated comprehensively, and the two-side properties differences were discussed. A convictive relationship between the morphologies and properties has been established, providing reliable and general guidance in terms of preparation of inorganic nanoparticles on plastic substrates. This novel and simple strategy can be extended to fabricate many other metal, metal oxide and metal sulfide nanoparticles on plastic substrates, using proper oxidants or sulfions to replace the diverse reductants. The films were characterized by inductively coupled plasma, contact angle measurement, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, four-point probe instrument and ultraviolet spectrophotometry

  3. Single-Commodity Vehicle Routing Problem with Pickup and Delivery Service

    Directory of Open Access Journals (Sweden)

    Goran Martinovic

    2008-01-01

    Full Text Available We present a novel variation of the vehicle routing problem (VRP. Single commodity cargo with pickup and delivery service is considered. Customers are labeled as either cargo sink or cargo source, depending on their pickup or delivery demand. This problem is called a single commodity vehicle routing problem with pickup and delivery service (1-VRPPD. 1-VRPPD deals with multiple vehicles and is the same as the single-commodity traveling salesman problem (1-PDTSP when the number of vehicles is equal to 1. Since 1-VRPPD specializes VRP, it is hard in the strong sense. Iterative modified simulated annealing (IMSA is presented along with greedy random-based initial solution algorithm. IMSA provides a good approximation to the global optimum in a large search space. Experiment is done for the instances with different number of customers and their demands. With respect to average values of IMSA execution times, proposed method is appropriate for practical applications.

  4. Uptake of methanol on mixed HNO3/H2O clusters: An absolute pickup cross section

    Science.gov (United States)

    Pysanenko, A.; Lengyel, J.; Fárník, M.

    2018-04-01

    The uptake of atmospheric oxidized organics on acid clusters is relevant for atmospheric new particle formation. We investigate the pickup of methanol (CH3OH) on mixed nitric acid-water clusters (HNO3)M(H2O)N by a combination of mass spectrometry and cluster velocity measurements in a molecular beam. The mass spectra of the mixed clusters exhibit (HNO3)m(H2O)nH+ series with m = 0-3 and n = 0-12. In addition, CH3OH.(HNO3)m(H2O)nH+ series with very similar patterns appear in the spectra after the methanol pickup. The velocity measurements prove that the undoped (HNO3)m(H2O)nH+ mass peaks in the pickup spectra originate from the neutral (HNO3)M(H2O)N clusters which have not picked up any CH3OH molecule, i.e., methanol has not evaporated upon the ionization. Thus the fraction of the doped clusters can be determined and the mean pickup cross section can be estimated, yielding σs ¯ ≈ 20 Å2. This is compared to the lower estimate of the mean geometrical cross section σg ¯ ≈ 60 Å2 obtained from the theoretical cluster geometries. Thus the "size" of the cluster corresponding to the methanol pickup is at least 3-times smaller than its geometrical size. We have introduced a method which can yield the absolute pickup cross sections relevant to the generation and growth of atmospheric aerosols, as illustrated in the example of methanol and nitric acid clusters.

  5. Capacitively coupled pickup in MCP-based photodetectors using a conductive metallic anode

    Energy Technology Data Exchange (ETDEWEB)

    Angelico, E.; Seiss, T. [Enrico Fermi Institute, University of Chicago, 5640 S Ellis Ave, Chicago, IL 60637 (United States); Adams, B. [Incom, Inc., 294 SouthBridge Rd, Charlton, Massachusetts 01507 (United States); Elagin, A.; Frisch, H.; Spieglan, E. [Enrico Fermi Institute, University of Chicago, 5640 S Ellis Ave, Chicago, IL 60637 (United States)

    2017-02-21

    We have designed and tested a robust 20×20 cm{sup 2} thin metal film internal anode capacitively coupled to an external array of signal pads or micro-strips for use in fast microchannel plate photodetectors. The internal anode, in this case a 10 nm-thick NiCr film deposited on a 96% pure Al{sub 2}O{sub 3} 3 mm-thick ceramic plate and connected to HV ground, provides the return path for the electron cascade charge. The multi-channel pickup array consists of a printed-circuit card or glass plate with metal signal pickups on one side and the signal ground plane on the other. The pickup can be put in close proximity to the bottom outer surface of the sealed photodetector, with no electrical connections through the photodetector hermetic vacuum package other than a single ground connection to the internal anode. Two pickup patterns were tested using a small commercial MCP-PMT as the signal source: 1) parallel 50 Ω 25-cm-long micro-strips with an analog bandwidth of 1.5 GHz, and 2) a 20×20 cm{sup 2} array of 2-dimensional square ‘pads’ with sides of 1.27 cm or 2.54 cm. The rise-time of the fast input pulse is maintained for both pickup patterns. For the pad pattern, we observe 80% of the directly coupled amplitude. For the strip pattern we measure 34% of the directly coupled amplitude on the central strip of a broadened signal. The physical decoupling of the photodetector from the pickup pattern allows easy customization for different applications while maintaining high analog bandwidth.

  6. Otolith oxygen isotopes measured by high-precision secondary ion mass spectrometry reflect life history of a yellowfin sole (Limanda aspera).

    Science.gov (United States)

    Matta, Mary Elizabeth; Orland, Ian J; Ushikubo, Takayuki; Helser, Thomas E; Black, Bryan A; Valley, John W

    2013-03-30

    The oxygen isotope ratio (δ(18)O value) of aragonite fish otoliths is dependent on the temperature and the δ(18)O value of the ambient water and can thus reflect the environmental history of a fish. Secondary ion mass spectrometry (SIMS) offers a spatial-resolution advantage over conventional acid-digestion techniques for stable isotope analysis of otoliths, especially given their compact nature. High-precision otolith δ(18)O analysis was conducted with an IMS-1280 ion microprobe to investigate the life history of a yellowfin sole (Limanda aspera), a Bering Sea species known to migrate ontogenetically. The otolith was cut transversely through its core and one half was roasted to eliminate organic contaminants. Values of δ(18)O were measured in 10-µm spots along three transects (two in the roasted half, one in the unroasted half) from the core toward the edge. Otolith annual growth zones were dated using the dendrochronology technique of crossdating. Measured values of δ(18)O ranged from 29.0 to 34.1‰ (relative to Vienna Standard Mean Ocean Water). Ontogenetic migration from shallow to deeper waters was reflected in generally increasing δ(18)O values from age-0 to approximately age-7 and subsequent stabilization after the expected onset of maturity at age-7. Cyclical variations of δ(18)O values within juvenile otolith growth zones, up to 3.9‰ in magnitude, were caused by a combination of seasonal changes in the temperature and the δ(18)O value of the ambient water. The ion microprobe produced a high-precision and high-resolution record of the relative environmental conditions experienced by a yellowfin sole that was consistent with population-level studies of ontogeny. Furthermore, this study represents the first time that crossdating has been used to ensure the dating accuracy of δ(18)O measurements in otoliths. Copyright © 2013 John Wiley & Sons, Ltd.

  7. Musical instrument pickup based on a laser locked to an optical fiber resonator.

    Science.gov (United States)

    Avino, Saverio; Barnes, Jack A; Gagliardi, Gianluca; Gu, Xijia; Gutstein, David; Mester, James R; Nicholaou, Costa; Loock, Hans-Peter

    2011-12-05

    A low-noise transducer based on a fiber Fabry-Perot (FFP) cavity was used as a pickup for an acoustic guitar. A distributed feedback (DFB) laser was locked to a 25 MHz-wide resonance of the FFP cavity using the Pound-Drever-Hall method. The correction signal was used as the audio output and was preamplified and sampled at up to 96 kHz. The pickup system is largely immune against optical noise sources, exhibits a flat frequency response from the infrasound region to about 25 kHz, and has a distortion-free audio output range of about 50 dB.

  8. Branch-and-Cut-and-Price for the Pickup and Delivery Problem with Time Windows

    DEFF Research Database (Denmark)

    Røpke, Stefan; Cordeau, Jean-Francois

    2009-01-01

    In the pickup and delivery problem with time windows (PDPTW), vehicle routes must be designed to satisfy a set of transportation requests, each involving a pickup and a delivery location, under capacity, time window, and precedence constraints. This paper introduces a new branch......-and-cut-and-price algorithm in which lower bounds are computed by solving through column generation the linear programming relaxation of a set partitioning formulation. Two pricing subproblems are considered in the column generation algorithm: an elementary and a non-elementary shortest path problem. Valid inequalities...

  9. Total external reflection X-ray fluorescence analysis of protein-metal ion interactions in biological systems

    Science.gov (United States)

    Novikova, N. N.; Kovalchuk, M. V.; Yur'eva, E. A.; Konovalov, O. V.; Rogachev, A. V.; Stepina, N. D.; Sukhorukov, V. S.; Tsaregorodtsev, A. D.; Chukhrai, E. S.; Yakunin, S. N.

    2012-09-01

    This paper presents the results of an investigation into hemoglobin-based protein films that were formed on a liquid surface. X-ray standing wave measurements were performed at the ID 10 beamline of the European Synchrotron Radiation Facility (ESRF) and at the Langmuir station of the Kurchatov Synchrotron Radiation Source. It was found that the ability of the protein to bind metal ions is substantially increased due to the conformational rearrangements of protein macromolecules caused by various damaging effects. The elemental composition of protein preparations, which were isolated from children and adults with chronic metabolic diseases accompanied by endogenous intoxication, was analyzed. The results of the investigations offer evidence that an increase in the ligand-binding properties of the protein molecules, which was observed in model experiments using protein films, is a common trait and corresponds to in vivo processes accompanying metabolic disturbances in the body.

  10. Final version of the pick-up wheels in the Pelletron tandem accelerator at Lund

    International Nuclear Information System (INIS)

    Hakansson, K.; Hellborg, R.

    1993-01-01

    A new type of pick-up wheel has been designed and constructed for the charge transport system of the Lund 3UDH Pelletron tandem accelerator. The major improvements compared with older types are a slender design with only one ball bearing and more robust contact pins with a rubber ring between the pinhead and the wheel nave. (orig.)

  11. (p, α) reactions: knock-on(out) or pick-up

    International Nuclear Information System (INIS)

    Gadioli, E.

    1983-01-01

    Nothwithstanding the great lot of data collected starting from the beginning of fifties, it cannot be said that a good degree of knowledge about the (p, α) reaction mechanism has been reached. Experimental data are usually interpreted or on the basis of a pure pick-up or knock-on(out) mechanism, though many results suggest the importance of both mechanism

  12. MgB2 magnetometer with directly coupled pick-up loop

    NARCIS (Netherlands)

    Portesi, C.; Mijatovic, D.; Veldhuis, Dick; Brinkman, Alexander; Monticone, E.; Gonnelli, R.S.

    2006-01-01

    magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which

  13. Comparison of magnetic and electrostatic Schottky pick-up in the CERN AD

    CERN Document Server

    Federmann, S

    2013-01-01

    The present note is intended to exploit the possibility of using a dedicated electrostatic beam pick-up for Schottky diagnostics in the future ELENA ring. A test setup is described allowing the evaluation of its performance compared to the extra low-noise beam current transformer used successfully in the AD. The results of this experiment are summarized and discussed.

  14. 47 CFR 74.431 - Special rules applicable to remote pickup stations.

    Science.gov (United States)

    2010-10-01

    ... occur outside the studio back to studio or production center. The transmitted material shall be intended... system. (b) Remote pickup mobile or base stations may be used for communications related to production..., Hawaii, Puerto Rico, and the Virgin Islands may be used for any purpose related to the programming or...

  15. What Skills and Tactics Are Needed to Play Adult Pick-Up Basketball Games?

    Science.gov (United States)

    Wang, Jianyu; Liu, Wenhao; Moffit, Jeffrey

    2010-01-01

    The purpose of this study was to examine skill levels and performance patterns of regular players of pick-up basketball games. By a survey, 65 participants were identified as regular players and participated in the study. An observational instrument used to analyze game performance of the participants was developed and both content and construct…

  16. Efficient isotope ratio analysis of uranium particles in swipe samples by total-reflection x-ray fluorescence spectrometry and secondary ion mass spectrometry

    International Nuclear Information System (INIS)

    Esaka, Fumitaka; Watanabe, Kazuo; Fukuyama, Hiroyasu; Onodera, Takashi; Esaka, Konomi T.; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu

    2004-01-01

    A new particle recovery method and a sensitive screening method were developed for subsequent isotope ratio analysis of uranium particles in safeguards swipe samples. The particles in the swipe sample were recovered onto a carrier by means of vacuum suction-impact collection method. When grease coating was applied to the carrier, the recovery efficiency was improved to 48±9%, which is superior to that of conventionally-used ultrasoneration method. Prior to isotope ratio analysis with secondary ion mass spectrometry (SIMS), total reflection X-ray fluorescence spectrometry (TXRF) was applied to screen the sample for the presence of uranium particles. By the use of Si carriers in TXRF analysis, the detection limit of 22 pg was achieved for uranium. By combining these methods with SIMS, the isotope ratios of 235 U/ 238 U for individual uranium particles were efficiently determined. (author)

  17. Carbon monoxide poisoning in children riding in the back of pickup trucks.

    Science.gov (United States)

    Hampson, N B; Norkool, D M

    OBJECTIVE - To describe the case characteristics of a series of children poisoned with carbon monoxide while traveling in the back of pickup trucks. DESIGN - Pediatric cases referred for treatment of carbon monoxide poisoning with hyperbaric oxygen between 1986 and 1991 were reviewed. Those cases that occurred during travel in the back of pickup trucks were selected. Clinical follow-up by telephone interview ranged from 2 to 55 months. SETTING - A private, urban, tertiary care center in Seattle, Wash. PATIENTS - Twenty children ranging from 4 to 16 years of age. INTERVENTION - All patients were treated with hyperbaric oxygen. MAIN OUTCOME MEASURES - Characteristics of the poisoning incident and clinical patient outcome. RESULTS - Of 68 pediatric patients treated for accidental carbon monoxide poisoning, 20 cases occurred as children rode in the back of pickup trucks. In 17 of these, the children were riding under a rigid closed canopy on the rear of the truck, while three episodes occurred as children rode beneath a tarpaulin. Average carboxyhemoglobin level on emergency department presentation was 18.2% +/- 2.4% (mean +/- SEM; range, 1.6% to 37.0%). Loss of consciousness occurred in 15 of the 20 children. One child died of cerebral edema, one had permanent neurologic deficits, and 18 had no recognizable sequelae related to the episode. In all cases, the truck exhaust system had a previously known leak or a tail pipe that exited at the rear rather than at the side of the pickup truck. CONCLUSIONS - Carbon monoxide poisoning is a significant hazard for children who ride in the back of pickup trucks. If possible, this practice should be avoided.

  18. Fully stripped heavy ion yield vs energy for Xe and Au ions

    International Nuclear Information System (INIS)

    Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

    1985-01-01

    The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe 54+ and U 92+ data are presented along with predictions for other ions ranging down to Fe 26+ . 11 refs., 3 figs., 1 tab

  19. Fully stripped heavy ion yield vs energy for Xe and Au ions

    Energy Technology Data Exchange (ETDEWEB)

    Thieberger, P.; Wegner, H.E.; Alonzo, J.; Gould, H.; Anholt, R.E.; Meyerhof, W.E.

    1985-01-01

    The Bevalac is now capable of accelerating U-238 ions to approximately 1 GeV/amu and measurements have shown that fully stripped U-238 ions are produced with good yield at these energies. However, knowing the stripping yields at different energies for U-238 does not allow an accurate prediction for other, lower Z projectiles. Consequently, extensive stripping yield measurements were made for Au-197 and Xe-139 ions. In addition to the stripping measurements from the direct Bevalac beam, pickup measurements were also made with specially prepared bare, one electron, and two electron ions. Since many research groups are considering heavy ion storage rings and/or synchrotrons, the pickup cross section for bare ions is important to estimate beam lifetime in terms of the average machine vacuum. Since the Mylar target provides a pickup probability similar to air, a preliminary analysis of the Xe/sup 54 +/ and U/sup 92 +/ data are presented along with predictions for other ions ranging down to Fe/sup 26 +/. 11 refs., 3 figs., 1 tab.

  20. Lifetime measurements in an electrostatic ion beam trap using image charge monitoring

    International Nuclear Information System (INIS)

    Rahinov, Igor; Toker, Yoni; Heber, Oded; Rappaport, Michael; Zajfman, Daniel; Strasser, Daniel; Schwalm, Dirk

    2012-01-01

    A technique for mass-selective lifetime measurements of keV ions in a linear electrostatic ion beam trap is presented. The technique is based on bunching the ions using a weak RF potential and non-destructive ion detection by a pick-up electrode. This method has no mass-limitation, possesses the advantage of inherent mass-selectivity, and offers a possibility of measuring simultaneously the lifetimes of different ion species with no need for prior mass-selection.

  1. The Influence of Pickup Protons, from Interstellar Neutral Hydrogen, on the Propagation of Interplanetary Shocks from the Halloween 2003 Solar Events to ACE and Ulysses: A 3-D MHD Modeling Study

    Science.gov (United States)

    Detman, T. R.; Intriligator, D. S.; Dryer, M.; Sun, W.; Deehr, C. S.; Intriligator, J.

    2012-01-01

    We describe our 3-D, time ]dependent, MHD solar wind model that we recently modified to include the physics of pickup protons from interstellar neutral hydrogen. The model has a time-dependent lower boundary condition, at 0.1 AU, that is driven by source surface map files through an empirical interface module. We describe the empirical interface and its parameter tuning to maximize model agreement with background (quiet) solar wind observations at ACE. We then give results of a simulation study of the famous Halloween 2003 series of solar events. We began with shock inputs from the Fearless Forecast real ]time shock arrival prediction study, and then we iteratively adjusted input shock speeds to obtain agreement between observed and simulated shock arrival times at ACE. We then extended the model grid to 5.5 AU and compared those simulation results with Ulysses observations at 5.2 AU. Next we undertook the more difficult tuning of shock speeds and locations to get matching shock arrival times at both ACE and Ulysses. Then we ran this last case again with neutral hydrogen density set to zero, to identify the effect of pickup ions. We show that the speed of interplanetary shocks propagating from the Sun to Ulysses is reduced by the effects of pickup protons. We plan to make further improvements to the model as we continue our benchmarking process to 10 AU, comparing our results with Cassini observations, and eventually on to 100 AU, comparing our results with Voyager 1 and 2 observations.

  2. Evaluation of strip-line pick-up system for the SPS wideband transverse feedback system

    CERN Document Server

    Kotzian, G; Steinhagen, R J; Valuch, D; Wehrle, U

    2017-01-01

    The proposed SPS Wideband Transverse Feedback sys- tem requires a wide-band pick-up system to be able to de- tect intra-bunch motion within the SPS proton bunches, captured and accelerated in a 200 MHz bucket. We present the electro-magnetic design of transverse beam position pick-up options optimised for installation in the SPS and evaluate their performance reach with respect to direct time domain sampling of the intra-bunch motion. The analy- sis also discusses the achieved subsystem responses of the associated cabling with new low dispersion smooth wall coaxial cables, wide-band generation of intensity and posi- tion signals by means of 180 degree RF hybrids as well as passive techniques to electronically suppress the beam off- set signal, needed to optimise the dynamic range and posi- tion resolution of the planned digital intra-bunch feedback system.

  3. Spin polarization of 34Al fragments produced by nucleon pickup at intermediate energies

    International Nuclear Information System (INIS)

    Turzo, K.; Himpe, P.; Borremans, D.; Mallion, S.; Neyens, G.; Vermeulen, N.; Yordanov, D.; Balabanski, D.L.; Belier, G.; Daugas, J.M.; Georgiev, G.; Oliveira de Santos, F.; Matea, I.; Stodel, Ch.; Penionzhkevich, Yu. E.

    2006-01-01

    The polarization of 34 Al fragments, produced by single neutron pickup from a 9 Be target by a 36 S projectile at 77.5 MeV/nucleon, have been observed at GANIL via the detection of resonantly destroyed β-asymmetry. The reaction-induced polarization is deduced using a tentative spin/parity assignment for the 34 Al ground state. A positive polarization was measured near the peak of the 34 Al yield curve. A kinematical model based on the spectator-participant model for projectile fragmentation reactions has been extended in order to take into account the features of pickup reactions, i.e., the picked-up nucleon having an average momentum equal to the Fermi momentum and aligned along the incident beam direction. The trend-line in the observed spin-orientation is very well reproduced by this model

  4. GRASP with path-relinking for the selective pickup and delivery problem

    DEFF Research Database (Denmark)

    Ho, Sin C.; Szeto, W. Y.

    2016-01-01

    Bike sharing systems are very popular nowadays. One of the characteristics is that bikes are picked up from some surplus bike stations and transported to all deficit bike stations by a repositioning vehicle with limited capacity to satisfy the demand of deficit bike stations. Motivated by this real...... world bicycle repositioning problem, we study the selective pickup and delivery problem, where demand at every delivery node has to be satisfied by the supply collected from a subset of pickup nodes. The objective is to minimize the total travel cost incurred from visiting the nodes. We present a GRASP...... with path-relinking for solving the described problem. Experimental results show that this simple heuristic improves the existing results in the literature with an average improvement of 5.72% using small computing times. The proposed heuristic can contribute to the development of effective and efficient...

  5. Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

    2012-07-01

    The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

  6. Pickup Protons: Comparisons using the Three-Dimensional MHD HHMS-PI model and Ulysses SWICS Measurements

    Science.gov (United States)

    Intriligator, Devrie S.; Detman, Thomas; Gloecker, George; Gloeckler, Christine; Dryer, Murray; Sun, Wei; Intriligator, James; Deehr, Charles

    2012-01-01

    We report the first comparisons of pickup proton simulation results with in situ measurements of pickup protons obtained by the SWICS instrument on Ulysses. Simulations were run using the three dimensional (3D) time-dependent Hybrid Heliospheric Modeling System with Pickup Protons (HHMS-PI). HHMS-PI is an MHD solar wind model, expanded to include the basic physics of pickup protons from neutral hydrogen that drifts into the heliosphere from the local interstellar medium. We use the same model and input data developed by Detman et al. (2011) to now investigate the pickup protons. The simulated interval of 82 days in 2003 2004, includes both quiet solar wind (SW) and also the October November 2003 solar events (the Halloween 2003 solar storms). The HHMS-PI pickup proton simulations generally agree with the SWICS measurements and the HHMS-PI simulated solar wind generally agrees with SWOOPS (also on Ulysses) measurements. Many specific features in the observations are well represented by the model. We simulated twenty specific solar events associated with the Halloween 2003 storm. We give the specific values of the solar input parameters for the HHMS-PI simulations that provide the best combined agreement in the times of arrival of the solar-generated shocks at both ACE and Ulysses. We show graphical comparisons of simulated and observed parameters, and we give quantitative measures of the agreement of simulated with observed parameters. We suggest that some of the variations in the pickup proton density during the Halloween 2003 solar events may be attributed to depletion of the inflowing local interstellar medium (LISM) neutral hydrogen (H) caused by its increased conversion to pickup protons in the immediately preceding shock.

  7. Experimental cross sections for the pickup of electrons by relativistic nuclei

    International Nuclear Information System (INIS)

    Raisbeck, G.M.; Crawford, H.J.; Lindstroem, P.J.; Greiner, D.E.; Beiser, F.S.; Heckman, H.H.

    1977-01-01

    Cross sections for the pickup of electrons in a variety of targets have been measured with beams of 12 C (150, 250, 400 MeV/n), 20 Ne (250, 400, 1050, 2100 MeV/n) and 40 Ar (400, 1050 MeV/n) from the Bevalac accelerator. The interpretation of the results in terms of radiative and non-radiative capture, and the implications for cosmic ray propagation studies are discussed. (author)

  8. Development of 80- and 100- Mile Work Day Cycles Representative of Commercial Pickup and Delivery Operation

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Adam W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kelly, Kenneth J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kresse, John [Cummins; Li, Ke [Cummins

    2018-04-03

    When developing and designing new technology for integrated vehicle systems deployment, standard cycles have long existed for chassis dynamometer testing and tuning of the powertrain. However, to this day with recent developments and advancements in plug-in hybrid and battery electric vehicle technology, no true 'work day' cycles exist with which to tune and measure energy storage control and thermal management systems. To address these issues and in support of development of a range-extended pickup and delivery Class 6 commercial vehicle, researchers at the National Renewable Energy Laboratory in collaboration with Cummins analyzed 78,000 days of operational data captured from more than 260 vehicles operating across the United States to characterize the typical daily performance requirements associated with Class 6 commercial pickup and delivery operation. In total, over 2.5 million miles of real-world vehicle operation were condensed into a pair of duty cycles, an 80-mile cycle and a 100-mile cycle representative of the daily operation of U.S. class 3-6 commercial pickup and delivery trucks. Using novel machine learning clustering methods combined with mileage-based weighting, these composite representative cycles correspond to 90th and 95th percentiles for daily vehicle miles traveled by the vehicles observed. In addition to including vehicle speed vs time drive cycles, in an effort to better represent the environmental factors encountered by pickup and delivery vehicles operating across the United States, a nationally representative grade profile and key status information were also appended to the speed vs. time profiles to produce a 'work day' cycle that captures the effects of vehicle dynamics, geography, and driver behavior which can be used for future design, development, and validation of technology.

  9. First-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Galactic Signal Contamination from Sidelobe Pickup

    Science.gov (United States)

    Barnes, C.; Hill, R. S.; Hinshaw, G.; Page, L.; Bennett, C. L.; Halpern, M.; Jarosik, N.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wollack, E.; Wright, E. L.

    2003-09-01

    Since the Galactic center is ~1000 times brighter than fluctuations in the cosmic microwave background (CMB), CMB experiments must carefully account for stray Galactic pickup. We present the level of contamination due to sidelobes for the first-year CMB maps produced by the Wilkinson Microwave Anisotropy Probe (WMAP) observatory. For each radiometer, full 4π sr antenna gain patterns are determined from a combination of numerical prediction and ground-based and space-based measurements. These patterns are convolved with the WMAP first-year sky maps and observatory scan pattern to generate the expected sidelobe signal contamination, for both intensity and polarized microwave sky maps. When the main beams are outside of the Galactic plane, we find rms values for the expected sidelobe pickup of 15, 2.1, 2.0, 0.3, and 0.5 μK for the K, Ka, Q, V, and W bands, respectively. Except for at the K band, the rms polarized contamination is the Galactic pickup are presented. WMAP is the result of a partnership between Princeton University and the NASA Goddard Space Flight Center. Scientific guidance is provided by the WMAP Science Team.

  10. Ac-loss measurement of coated conductors: The influence of the pick-up coil position

    International Nuclear Information System (INIS)

    Schmidt, Curt

    2008-01-01

    The ac-loss measurement by the magnetization method requires calibration for obtaining absolute values. A convenient way of calibration is the calorimetric measurement which yields, within the measuring accuracy, absolute loss values. In the magnetization measurement the hysteresis loop of sample magnetization which determines the losses is measured via the integration of magnetic flux penetrating a pick-up coil. The ratio of flux integral to magnetization integral and hence the calibration factor is however, for a given pick-up coil geometry, not exactly a constant, but depends on the magnetization current pattern within the sample. Especially for thin tapes in perpendicular external field this effect has to be taken into consideration in order to avoid miss measurements. The relation between measured flux and sample magnetization was calculated for special cases of magnetization current distribution in the sample as a function of the pick-up coil position. Furthermore calibration factors were measured as a function of the ac-field amplitude and the result compared with available theoretical models. A good agreement was found between experiment and theory

  11. Tracked "Pick-Up" Ultrasound for Robot-Assisted Minimally Invasive Surgery.

    Science.gov (United States)

    Schneider, Caitlin; Nguan, Christopher; Rohling, Robert; Salcudean, Septimiu

    2016-02-01

    We present a novel "pick-up" ultrasound transducer for intraabdominal robot-assisted minimally invasive surgery. Such a "pick-up" ultrasound transducer is inserted through an abdominal incision at the beginning of the procedure and remains in the abdominal cavity throughout, eliminating the need for a dedicated port or a patient bedside surgical assistant. The transducer has a handle that can be grasped in a repeatable manner using a da Vinci Prograsp tool, allowing the transducer to be accurately manipulated by the surgeon using the da Vinci Robot. This is one way to enable 3-D tracking of the transducer, and, thus, mapping of the vasculature. The 3-D vascular images can be used to register preoperative CT to intraoperative camera images. To demonstrate the feasibility of the approach, we use an ultrasound vessel phantom to register a CT surface model to extracted ultrasound vessel models. The 3-D vascular phantom images are generated by segmenting B-mode images and tracking the pick-up ultrasound transducer with the da Vinci kinematics, internal electromagnetic sensor, or visible fiducials suitable for camera tracking. Reconstruction results using da Vinci kinematics for tracking give a target registration error of 5.4 ± 1.7 mm.

  12. High-lying neutron hole strengths observed in pick-up reactions

    International Nuclear Information System (INIS)

    Gales, S.

    1980-01-01

    Neutron-hole states in orbits well below the Fermi surface have been observed in a number of medium-heavy nuclei from A=90 to 209 using one nucleon pick-up reactions. The excitation energies, angular distributions of such broad and enhanced structures will be discussed. The fragmentation of the neutron-hole strengths as well as the spreading of such simple mode of excitations into more complex states are compared to recent calculations within the quasiparticle-phonon or the single particle-vibration coupling nuclear models. We report on recent measurements of J for inner-hole states in 89 Zr and 115 Sn 119 Sn using the analyzing power of the (p,d) and (d,t) reactions. Large enhancement of cross-sections are observed at high excitation energy in the study of the (p,t) reactions on Zr, Cd, Sn, Te and Sm isotopes. The systematic features of such high-lying excitation are related to the ones observed in one neutron pick-up experiments. The origin of such concentration of two neutron-hole strengths in Cd and Sn isotopes will be discussed. Preliminary results obtained in the study of the (α, 6 He) reaction at 218 MeV incident energy on 90 Zr, 118 Sn and 208 Pb targets are presented and compared to the (p,t) results. Finally the properties of hole-analog states populated in neutron pick-up reactions (from 90 Zr to 208 Pb) will be presented

  13. A Catalytic Path for Electrolyte Reduction in Lithium-Ion Cells Revealed by in Situ Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy

    KAUST Repository

    Shi, Feifei; Ross, Philip N.; Zhao, Hui; Liu, Gao; Somorjai, Gabor A.; Komvopoulos, Kyriakos

    2015-01-01

    © 2015 American Chemical Society. Although controlling the interfacial chemistry of electrodes in Li-ion batteries (LIBs) is crucial for maintaining the reversibility, electrolyte decomposition has not been fully understood. In this study, electrolyte decomposition on model electrode surfaces (Au and Sn) was investigated by in situ attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Simultaneously obtained ATR-FTIR spectra and cyclic voltammetry measurements show that lithium ethylene dicarbonate and lithium propionate form on the Au electrode at 0.6 V, whereas diethyl 2,5-dioxahexane dicarboxylate and lithium propionate form on the Sn electrode surface at 1.25 V. A noncatalytic reduction path on the Au surface and a catalytic reduction path on the Sn surface are introduced to explain the surface dependence of the overpotential and product selectivity. This represents a new concept for explaining electrolyte reactions on the anode of LIBs. The present investigation shows that catalysis plays a dominant role in the electrolyte decomposition process and has important implications in electrode surface modification and electrolyte recipe selection, which are critical factors for enhancing the efficiency, durability, and reliability of LIBs.

  14. A Catalytic Path for Electrolyte Reduction in Lithium-Ion Cells Revealed by in Situ Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy

    KAUST Repository

    Shi, Feifei

    2015-03-11

    © 2015 American Chemical Society. Although controlling the interfacial chemistry of electrodes in Li-ion batteries (LIBs) is crucial for maintaining the reversibility, electrolyte decomposition has not been fully understood. In this study, electrolyte decomposition on model electrode surfaces (Au and Sn) was investigated by in situ attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Simultaneously obtained ATR-FTIR spectra and cyclic voltammetry measurements show that lithium ethylene dicarbonate and lithium propionate form on the Au electrode at 0.6 V, whereas diethyl 2,5-dioxahexane dicarboxylate and lithium propionate form on the Sn electrode surface at 1.25 V. A noncatalytic reduction path on the Au surface and a catalytic reduction path on the Sn surface are introduced to explain the surface dependence of the overpotential and product selectivity. This represents a new concept for explaining electrolyte reactions on the anode of LIBs. The present investigation shows that catalysis plays a dominant role in the electrolyte decomposition process and has important implications in electrode surface modification and electrolyte recipe selection, which are critical factors for enhancing the efficiency, durability, and reliability of LIBs.

  15. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...

  16. Water group ion distributions in the midcometosheath of comet Halley

    Science.gov (United States)

    Huddleston, D. E.; Neugebauer, M.; Goldstein, Bruce E.

    1993-01-01

    In the midcometosheath of comet Halley (1 x 10(exp 5) to 2 x 10(exp 5) km from the nucleus) the center-of-mass plasma frame is approximately the bulk flow velocity of the cometary ions, and the Alfven wave speed is an appreciable fraction of the flow speed. Here, the peaks of the water group ion distributions observed by the Giotto ion mass spectrometer are at velocities consistently below the expected pickup speed. It is shown that this effect is consistent with the scattering of the new pickup ions onto a bispherical shell distribution. The model does not fit the data inside approximately 1.2 x 10(exp 5) km, however, possibly as a result of the growing importance of collisions or the presence of other processes such as scattering on obliquely propagating magnetosonic waves.

  17. Simulation study of wave phenomena from the sheath region in single frequency capacitively coupled plasma discharges; field reversals and ion reflection

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S.; Turner, M. M. [National Centre for Plasma Science and Technology, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)

    2013-07-15

    Capacitively coupled radio-frequency (RF) discharges have great significance for industrial applications. Collisionless electron heating in such discharges is important, and sometimes is the dominant mechanism. This heating is usually understood to originate in a stochastic interaction between electrons and the electric fields. However, other mechanisms may also be important. There is evidence of wave emission with a frequency near the electron plasma frequency, i.e., ω{sub pe}, from the sheath region in collisionless capacitive RF discharges. This is the result of a progressive breakdown of quasi-neutrality close to the electron sheath edge. These waves are damped in a few centimeters during their propagation from the sheath towards the bulk plasma. The damping occurs because of the Landau damping or some related mechanism. This research work reports that the emission of waves is associated with a field reversal during the expanding phase of the sheath. Trapping of electrons near to this field reversal region is observed. The amplitude of the wave increases with increasing RF current density amplitude J(tilde sign){sub 0} until some maximum is reached, beyond which the wave diminishes and a new regime appears. In this new regime, the density of the bulk plasma suddenly increases because of ion reflection, which occurs due to the presence of strong field reversal near sheath region. Our calculation shows that these waves are electron plasma waves. These phenomena occur under extreme conditions (i.e., higher J(tilde sign){sub 0} than in typical experiments) for sinusoidal current waveforms, but similar effects may occur with non-sinusoidal pulsed waveforms for conditions of experimental interest, because the rate of change of current is a relevant parameter. The effect of electron elastic collisions on plasma waves is also investigated.

  18. An assessment of the waterside corrosion and hydrogen pick-up in the zircaloy-2 pressure tubes of PHWR

    International Nuclear Information System (INIS)

    Sah, D.N.

    1992-01-01

    In view of the deleterious effect of hydriding on the operating life of zircaloy-2 pressure tubes in PHWRs there is an urgent need for the assessment of the status of the pressure tubes with respect to corrosion and hydrogen pick-up in the operating PHWRs. A model has been developed for analysing the waterside corrosion and hydrogen pick-up in the zircaloy-2 pressure tubes under reactor operating conditions. This model predicts the axial profiles of oxide layer thickness and hydrogen pick-up in the pressure tubes as a function of the operating time of the reactor. The prediction of hydrogen pick-up by the model in the F-10 pressure tube of RAPS-I have been found to be in good agreement with the measured value of hydrogen content. This report gives a brief description of the model and its predictions on the present status of hydrogen pick-up in the pressure tubes of lead reactor RAPS-II. (author). 6 refs., 5 figs., 2 tabs

  19. On measuring the UNK SC-dipole bending strength with rotating pick-up coil

    International Nuclear Information System (INIS)

    Smirnov, N.L.; Tikhov, A.V.

    1993-01-01

    The experience in measuring the SC-dipole bending strength with the spotting method shown this measurement to be the most complicated and expensive. A convenient and simple method of rotating pick-up coil, which can not provide the required accuracy, may be used for this measurement combined with NMR measurements in the dipole central part. The physical ground and description of the method are given in the paper. The analysis of the errors and measurement results of the SPDMI SC-dipoles are presented. 9 refs..; 7 figs

  20. An experimental study of odd mass promethium isotopes using proton stripping and pickup reactions

    International Nuclear Information System (INIS)

    Straume, O.

    1979-11-01

    Odd Pm isotopes have been studied by one proton pick-up and stripping reactions. Spin assignment and spectroscopic factors have been obtained for a number of energy levels. In the stripping reactions, the relative cross-sections have been measured with an unusually high precision by the use of a target of natural neodymium. The spectroscopic strengths have been extracted using standard distorted wave methods. The nuclear structures of these promethium isotopes fall into three categories. The spherical approach seems valid for 143 Pm and 145 Pm and the deformed regime covers 151 Pm and 153 Pm, while 147 Pm and 149 Pm remain as transitional nuclei. (Auth.)

  1. Testbeam Studies on Pick-Up in Sensors with Embedded Pitch Adapters

    CERN Document Server

    Rehnisch, Laura; The ATLAS collaboration

    2018-01-01

    Embedded pitch adapters are an alternative solution to external pitch adapters widely used to facilitate the wire-bonding step when connecting silicon strip sensors and readout electronics of different pitch. The pad-pitch adaption can be moved into the sensor fabrication step by implementing a second layer of metal tracks, connected by vias to the primary metal layer of sensor strips. Such a solution, however, might bear the risk of performance losses introduced by various phenomena. One of these effects, the undesired capacitive coupling between the silicon bulk and this second metal layer (pick-up) has been investigated in photon testbeam measurements. For a worst-case embedded pitch adapter design, expected to be maximally susceptible to pick-up, a qualitative analysis has visualized the effect as a function of the location on the second metal layer structure. It was further found that the unwanted effect decreases towards expected values for operating thresholds of the binary readout used. Suggestions fo...

  2. New formulation and branch-and-cut algorithm for the pickup and delivery traveling salesman problem with multiple stacks: new formulation and branch-and-cut algorithm

    NARCIS (Netherlands)

    Sampaio Oliveira, A.H.; Urrutia, S.

    2017-01-01

    In this paper, we consider the pickup and delivery traveling salesman problem with multiple stacks in which a single vehicle must serve a set of customer requests defined by a pair of pickup and delivery destinations of an item. The vehicle contains a fixed number of stacks, where each item is

  3. Isotopic and velocity distributions of {sub 83}Bi produced in charge-pickup reactions of {sup 208}{sub 82}PB at 1 A GeV

    Energy Technology Data Exchange (ETDEWEB)

    Kelic, A.; Schmidt, K.H.; Enqvist, T. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (DE)] [and others

    2004-07-01

    Isotopically resolved cross sections and velocity distributions have been measured in charge-pickup reactions of 1 A GeV {sup 208}Pb with proton, deuterium and titanium target. The total and partial charge-pickup cross sections in the reactions {sup 208}Pb + {sup 1}H and {sup 208}Pb + {sup 2}H are measured to be the same in the limits of the error bars. A weak increase in the total charge-pickup cross section is seen in the reaction of {sup 208}Pb with the titanium target. The measured velocity distributions show different contributions - quasi-elastic scattering and {delta}-resonance excitation - to the charge-pickup production. Data on total and partial charge-pickup cross sections from these three reactions are compared with other existing data and also with model calculations based on the coupling of different intra-nuclear cascade codes and an evaporation code. (orig.)

  4. The role of charge-exchange cross-section for pickup protons and neutrals in the inner heliosheath

    Science.gov (United States)

    Chalov, S. V.

    2018-06-01

    The process of deceleration of the solar wind downstream of the termination shock is studied on the basis of a one-dimensional multi-component model. It is assumed that the solar wind consists of thermal protons, electrons and interstellar pickup protons. The protons interact with interstellar hydrogen atoms by charge-exchange. Two cases are considered. In the first one, the charge-exchange cross-section for thermal protons and hydrogen atoms is the same as for pickup protons and atoms. Under this condition, there is a strong dependence of the solar wind velocity on the downstream temperature of pickup protons. When the proton temperature is close to 10 keV, the change in the velocity with the distance from the termination shock is similar to that measured on the Voyager 1 spacecraft: linear velocity decrease is accompanied by an extended transition region with near-zero velocity. However, with a more careful approach to the choice of the charge-exchange cross-section, the situation changes dramatically. The strong dependence of the solar wind speed on the pickup proton temperature disappears and the transition region in the heliosheath disappears as well, at least at reasonable distances from the TS.

  5. An adaptive large neighborhood search heuristic for the pickup and delivery problem with time Windows and scheduled lines

    NARCIS (Netherlands)

    Ghilas, V.; Demir, E.; van Woensel, T.

    2016-01-01

    The Pickup and Delivery Problem with Time Windows and Scheduled Lines (PDPTW-SL) concerns scheduling a set of vehicles to serve freight requests such that a part of the journey can be carried out on a scheduled public transportation line. Due to the complexity of the problem, which is NP-hard, we

  6. 49 CFR 1242.76 - Administration; pickup and delivery, marine line haul, and rail substitute service; loading...

    Science.gov (United States)

    2010-10-01

    ... haul, and rail substitute service; loading, unloading and local marine; protective services; freight... SEPARATION OF COMMON OPERATING EXPENSES BETWEEN FREIGHT SERVICE AND PASSENGER SERVICE FOR RAILROADS 1 Operating Expenses-Transportation § 1242.76 Administration; pickup and delivery, marine line haul, and rail...

  7. An Inventory-Routing Problem with Pickups and Deliveries Arising in the Replenishment of Automated Teller Machines

    NARCIS (Netherlands)

    van Anholt, Roel G.; Coelho, Leandro C.; Laporte, Gilbert; Vis, Iris F. A.

    The purpose of this paper is to introduce, model, and solve a rich multiperiod inventory-routing problem with pickups and deliveries motivated by the replenishment of automated teller machines in the Netherlands. Commodities can be brought to and from the depot, as well as being exchanged among

  8. An inventory-routing problem with pickups and deliveries arising in the replenishment of automated teller machines

    NARCIS (Netherlands)

    Van Anholt, Roel G.; Coelho, Leandro C.; Laporte, Gilbert; Vis, Iris F.A.

    2016-01-01

    The purpose of this paper is to introduce, model, and solve a rich multiperiod inventory-routing problem with pickups and deliveries motivated by the replenishment of automated teller machines in the Netherlands. Commodities can be brought to and from the depot, as well as being exchanged among

  9. Review of theoretical conceptions on regimes of oxidation and hydrogen pickup in Zr-alloys

    International Nuclear Information System (INIS)

    Likhanskii, V.; Evdokimov, I.

    2008-01-01

    In this paper the following issues are presented: 1) Experimental observations published in the journals on corrosion regimes of zirconium alloys of various compositions both for ex-pile oxidation experiments and for in-pile operating conditions of the materials. Factors experimentally stated on the effect of alloying composition, microstructure and texture on the rate of uniform corrosion and susceptibility of alloys to nodular corrosion. 2) Phenomenological models existing in publications, which describe conditions of uniform and nodular corrosion for Zr-alloys of various composition and microstructures, effect of irradiation and oxidizing medium; 3) Experimental data and phenomenological models describing regimes of hydrogen absorption in zirconium alloys; 4) Examples of application of physical models in explaining regimes, peculiarities of oxidation and hydrogen pickup for zirconium claddings of various alloying composition and microstructure

  10. Automatic pickup of arrival time of channel wave based on multi-channel constraints

    Science.gov (United States)

    Wang, Bao-Li

    2018-03-01

    Accurately detecting the arrival time of a channel wave in a coal seam is very important for in-seam seismic data processing. The arrival time greatly affects the accuracy of the channel wave inversion and the computed tomography (CT) result. However, because the signal-to-noise ratio of in-seam seismic data is reduced by the long wavelength and strong frequency dispersion, accurately timing the arrival of channel waves is extremely difficult. For this purpose, we propose a method that automatically picks up the arrival time of channel waves based on multi-channel constraints. We first estimate the Jaccard similarity coefficient of two ray paths, then apply it as a weight coefficient for stacking the multichannel dispersion spectra. The reasonableness and effectiveness of the proposed method is verified in an actual data application. Most importantly, the method increases the degree of automation and the pickup precision of the channel-wave arrival time.

  11. Ship Routing with Pickup and Delivery for a Maritime Oil Transportation System: MIP Modeland Heuristics

    DEFF Research Database (Denmark)

    Rodrigues, Vinicius Picanco; Morabito, Reinaldo; Yamashita, Denise

    2016-01-01

    This paper examines a ship routing problem with pickup and delivery and time windowsfor maritime oil transportation, motivated by the production and logistics activities of an oil companyoperating in the Brazilian coast. The transportation costs from offshore platforms to coastal terminalsare...... application of two tailor-made MIP heuristics, based on relax-and-fix and timedecomposition procedures. The model minimizes fuel costs of a heterogeneous fleet of oil tankersand costs related to freighting contracts. The model also considers company-specific constraints foroffshore oil transportation....... Computational experiments based on the mathematical models and therelated MIP heuristics are presented for a set of real data provided by the company, which confirmthe potential of optimization-based methods to find good solutions for problems of moderate sizes....

  12. Simulated annealing with restart strategy for the blood pickup routing problem

    Science.gov (United States)

    Yu, V. F.; Iswari, T.; Normasari, N. M. E.; Asih, A. M. S.; Ting, H.

    2018-04-01

    This study develops a simulated annealing heuristic with restart strategy (SA_RS) for solving the blood pickup routing problem (BPRP). BPRP minimizes the total length of the routes for blood bag collection between a blood bank and a set of donation sites, each associated with a time window constraint that must be observed. The proposed SA_RS is implemented in C++ and tested on benchmark instances of the vehicle routing problem with time windows to verify its performance. The algorithm is then tested on some newly generated BPRP instances and the results are compared with those obtained by CPLEX. Experimental results show that the proposed SA_RS heuristic effectively solves BPRP.

  13. A Mutualism Quantum Genetic Algorithm to Optimize the Flow Shop Scheduling with Pickup and Delivery Considerations

    Directory of Open Access Journals (Sweden)

    Jinwei Gu

    2015-01-01

    Full Text Available A mutualism quantum genetic algorithm (MQGA is proposed for an integrated supply chain scheduling with the materials pickup, flow shop scheduling, and the finished products delivery. The objective is to minimize the makespan, that is, the arrival time of the last finished product to the customer. In MQGA, a new symbiosis strategy named mutualism is proposed to adjust the size of each population dynamically by regarding the mutual influence relation of the two subpopulations. A hybrid Q-bit coding method and a local speeding-up method are designed to increase the diversity of genes, and a checking routine is carried out to ensure the feasibility of each solution; that is, the total physical space of each delivery batch could not exceed the capacity of the vehicle. Compared with the modified genetic algorithm (MGA and the quantum-inspired genetic algorithm (QGA, the effectiveness and efficiency of the MQGA are validated by numerical experiments.

  14. Study of the continuum in heavy ion inelastic spectra by light particle coincidence measurements

    International Nuclear Information System (INIS)

    Scarpaci, J.A.; Blumenfeld, Y.; Chomaz, P.; Frascaria, N.; Garron, J.P.; Roynette, J.C.; Suomijarvi, T.; Van der Woude, A.; Alamanos, N.; Fernandez, B.; Gillibert, A.; Van der Woude, A.; Lepine, A.

    1990-01-01

    The continuum in heavy ion inelastic spectra contains, in addition to the excitation of target nucleus states, contributions from pick-up break-up and knock out reactions. In the case of the 40 Ca + 40 Ca collision at 50 MeV/N these contributions are separated and their relative importance assessed by the measurement of light charged particles in coincidence with the inelastically scattered fragments. The pick-up break-up contribution is found to make up less than half of the cross section at high excitation energies, conversely, the knock out process is important

  15. Beam emittance measurements on multicusp ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Sarstedt, M.; Lee, Y.; Leung, K.N. [and others

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 {mu}m patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma.

  16. Beam emittance measurements on multicusp ion sources

    International Nuclear Information System (INIS)

    Sarstedt, M.; Lee, Y.; Leung, K.N.

    1995-08-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 μm patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf-pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of an rf-generated plasma

  17. Resonant interactions between cometary ions and low frequency electromagnetic waves

    Science.gov (United States)

    Thorne, Richard M.; Tsurutani, Bruce T.

    1987-01-01

    The conditions for resonant wave amplification in a plasma with a ring-beam distribution which is intended to model pick-up ions in a cometary environment are investigated. The inclination between the interplanetary field and the solar wind is found to play a crucial role in governing both the resonant frequency and the growth rate of any unstable mode. It is suggested that the low-frequency MHD mode should experience the most rapid amplification for intermediate inclination. In the frame of the solar wind, such waves should propagate along the field in the direction upstream toward the sun with a phase speed lower than the beaming velocity of the pick-up ions. This mechanism may account for the presence of the interior MHD waves noted by satellites over a region surrounding comets Giacobini-Zinner and Halley.

  18. Lubricant Film Breakdown and Material Pick-Up in Sheet Forming of Advanced High Strength Steels and Stainless Steels when Using Environmental Friendly Lubricants

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Olsson, M.; Bay, Niels

    2014-01-01

    chemically with the tool and workpiece material forming thin films, which adhere strongly to the surfaces and reduce the tendency to metal-metal contact and material pick-up. Production tests of new, environmentally benign tribo-systems are, however, costly and laboratory tests are preferred as a preliminary...... the tribological performance, i.e. tendency to material pick-up and galling, of the evaluated tribo-systems. Moreover the SEM analysis shows that different workpiece materials result in different types of material pick-up....

  19. The effect of minor alloying elements on oxidation and hydrogen pickup in Zr-2.5Nb

    International Nuclear Information System (INIS)

    Ploc, R.A.

    2002-01-01

    In CANDU reactors, fuel and coolant are contained in horizontal pressure tubes made of Zr-2.5 wt% Nb alloy. In the past decade, the effect of more than 20 impurity elements, in various concentrations, on oxidation and deuterium pickup (at 300 o C, pD = 10.5, Li 2 O) have been investigated in over 70 Zr-2.5Nb alloys. The studies were performed using non-consumable arc-melted alloy logs that were rolled and made into corrosion coupons and corroded in autoclaves. This study represents one of the largest collections of previously unpublished data on the effect of impurity elements on oxide film growth and deuterium pickup in a zirconium alloy. Elements such as Al, Ti, Mn, and Pt, to name but a few, were found to significantly accelerate the corrosion process. Some elements, such as tin, had a positive effect on oxidation (lowers the rate of oxide film development) and a negative effect on hydrogen pickup (increases pickup). Three parameters were important to the corrosion process, namely, microstructure, surface finish, and synergistic interactions between the impurity elements. The above studies culminated in two response surface analyses (RSA). The first was conducted on the effect of C and Fe on oxygen and deuterium pickup in Zr-2.5Nb drop castings corroded at 325 o C in CANDU conditions. The second study was performed in autoclaves at 300 o C on the affect of four impurity elements, C, Fe, Cr, and Si, in Zr-2.5Nb micro-tubes, which possess the same microstructure as full-size pressure tubes. The first RSA revealed a quadratic dependence of corrosion on C and Fe concentrations, with an optimum resistance at about 30 ppm (wt) C and 1100 ppm (wt) Fe. This has been partially confirmed by out-reactor corrosion of Zr-2.5Nb-Fe micro-pressure tubes. Trends in- and out-reactor were similar for oxidation but different in magnitude for deuterium pickup. There is no linear dependence on the Fe concentration in-reactor, implying that Fe and C form a complex. The second RSA

  20. The effect of minor alloying elements on oxidation and hydrogen pickup in Zr-2.5Nb

    International Nuclear Information System (INIS)

    Ploc, R.A.

    2002-01-01

    In CANDU reactors, fuel and coolant are contained in horizontal pressure tubes made of Zr-2.5 wt% Nb alloy. In the past decade, the effect of more than 20 impurity elements, in various concentrations, on oxidation and deuterium pickup (at 300 deg C, pD = 10.5, Li 2 O) have been investigated in over 70 Zr-2.5Nb alloys. The studies were performed using non-consumable arc-melted alloy logs that were rolled and made into corrosion coupons and corroded in autoclaves. This study represents one of the largest collections of previously unpublished data on the effect of impurity elements on oxide film growth and deuterium pickup in a zirconium alloy. Elements such as Al, Ti, Mn, and Pt, to name but a few, were found to significantly accelerate the corrosion process. Some elements, such as tin, had a positive effect on oxidation (lowers the rate of oxide film development) and a negative effect on hydrogen pickup (increases pickup). Three parameters were important to the corrosion process, namely, microstructure, surface finish, and synergistic interactions between the impurity elements. The above studies culminated in two response surface analyses (RSA). The first was conducted on the effect of C and Fe on oxygen and deuterium pickup in Zr-2.5Nb drop castings corroded at 325 deg C in CANDU conditions. The second study was performed in autoclaves at 300 deg C on the affect of four impurity elements, C, Fe, Cr, and Si, in Zr-2.5Nb micro-tubes, which possess the same microstructure as full-size pressure tubes. The first RSA revealed a quadratic dependence of corrosion on C and Fe concentrations, with an optimum resistance at about 30 ppm (wt) C and 1100 ppm (wt) Fe. This has been partially confirmed by out-reactor corrosion of Zr-2.5Nb-Fe micro-pressure tubes. Trends in- and out-reactor were similar for oxidation but different in magnitude for deuterium pickup. There is no linear dependence on the Fe concentration in-reactor, implying that Fe and C form a complex. The second

  1. Water-Group Ion Distributions in the Mid-Cometosheath of Comet Halley

    Science.gov (United States)

    Huddleston, D. E.; Neugebauer, M.; Goldstein, B. E.

    1993-01-01

    In the mid-cometosheath of comet Halley (1-2x10^5 km from the nucleus) the center- of-mass plasma frame is approximately the bulk flow velocity of the cometary ions, and the Alfven wave speed is an appreciable fraction of the flow speed. Here, the peaks of the water-group ion distributions observed by the Giotto Ion Mass Spectrometer are at velocities consistently below the expected pickup speed. It is shown that this effect is consistent with the scattering of the new pickup ions onto a bispherical shell distribution. The model does not fit the data inside similar 1.2x10^5 km however, possibly as a result of the growing importance of collisions or the presence of other processes such as scattering on obliquely-propagating magnetosonic waves.

  2. The Reflective Learning Continuum: Reflecting on Reflection

    Science.gov (United States)

    Peltier, James W.; Hay, Amanda; Drago, William

    2005-01-01

    The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research that considers reflection within the context of both the marketing and general business education literature. This article describes the use of an instrument that can be used to measure four identified levels of a…

  3. Polarization of {sup 23}Ne, {sup 24m,25}Al and {sup 28}P produced through single nucleon pickup and charge-exchange reactions at 100 AMeV

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsubo, T., E-mail: tohtsubo@np.gs.niigata-u.ac.jp; Hirano, H.; Takahashi, S. [Niigata Univ. (Japan); Matsuta, K.; Mihara, M.; Fukuda, M. [Osaka Univ. (Japan); Nagatomo, T. [RIKEN (Japan); Izumikawa, T. [Niigata Univ., RI Center (Japan); Momota, S. [Kochi Univ. of Tech. (Japan); Nishimura, D.; Komurasaki, J.; Ishikawa, D. [Osaka Univ. (Japan); Zhou, D. M.; Zheng, Y. N.; Zhu, S. Y. [China Institute of Atomic Energy (China); Kitagawa, A.; Kanazawa, M.; Torikoshi, M.; Sato, S. [Inage-ku, NIRS (Japan); Minamisono, T. [Fukui Univ. of Tech. (Japan)

    2007-11-15

    We measured the polarization of the {beta}-emitting {sup 23}Ne (I{sup {pi}} 5/2{sup +}, T{sub 1/2} = 37.24 s) and {sup 25}Al(I{sup {pi}} = 5/2{sup +}, T{sub 1/2} = 7.18 s) produced through the one nucleon pickup reactions and {sup 24m}Al(I{sup {pi}} = 1{sup +}, T{sub 1/2} 131 ms, E{sub ex} = 426 keV) and {sup 28}P(I{sup {pi}} = 3{sup +}, T{sub 1/2} = 270 ms) produced through charge-exchange reactions in the intermediate energy heavy ion collisions. We compared them with those from the projectile fragmentation process. The larger polarization seems to persistently be positive throughout the momentum distribution, and sharper momentum distributions suggest that nuclear friction mechanism is responsible for the polarization phenomena.

  4. Calculation of deuterium retention, re-emission and reflection from a tungsten material under D+ ions irradiation with ACAT-DIFFUSE code

    International Nuclear Information System (INIS)

    Ono, T.; Kenmotsu, T.; Muramoto, T.; Kawamura, T.

    2009-01-01

    We calculated, with a dynamic Monte Carlo code ACAT-DIFFUSE, fluxes of thermal D 2 re-emission, reflection and segregated self-sputtering of D from a D + implanted wrought tungsten material during a time sequence of l00 eV D + implantation, post-implanted isothermal out-gassing and thermal desorption spectroscopy. The obtained result was in good agreement with an existing experiment if two different trap sites with de-trapping energy of 0.85 eV and 2.2 eV and density fraction of 0.05 D/W and 0.01 D/W were assumed to exist. The re-emission, reflection and self-sputtering fluxes in the implantation period were shown to be almost comparable. The integrated deuterium flux released in the same period was estimated. The amount of deuterium retained at 300 K was nearly six times higher than that at 473 K, which reflects the result that mobile atoms and atoms trapped in 0.85 eV trap existed abundantly at 300 K but scarcely at 473 K.

  5. Review of high excitation energy structures in heavy ion collisions: target excitations and three body processes

    International Nuclear Information System (INIS)

    Frascaria, N.

    1987-09-01

    A review of experimental results on high excitation energy structures in heavy ion inelastic scattering is presented. The contribution to the spectra of the pick-up break-up mechanism is discussed in the light of the data obtained with light heavy ion projectiles. Recent results obtained with 40 Ar beams at various energies will show that target excitations contribute strongly to the measured cross section

  6. Exact Solutions to the Symmetric and Asymmetric Vehicle Routing Problem with Simultaneous Delivery and Pick-Up

    Directory of Open Access Journals (Sweden)

    Julia Rieck

    2013-05-01

    Full Text Available In reverse logistics networks, products (e.g., bottles or containers have to be transported from a depot to customer locations and, after use, from customer locations back to the depot. In order to operate economically beneficial, companies prefer a simultaneous delivery and pick-up service. The resulting Vehicle Routing Problem with Simultaneous Delivery and Pick-up (VRPSDP is an operational problem, which has to be solved daily by many companies. We present two mixed-integer linear model formulations for the VRPSDP, namely a vehicle-flow and a commodity-flow model. In order to strengthen the models, domain-reducing preprocessing techniques, and effective cutting planes are outlined. Symmetric benchmark instances known from the literature as well as new asymmetric instances derived from real-world problems are solved to optimality using CPLEX 12.1.

  7. The Multi-commodity One-to-one Pickup-and-delivery Traveling Salesman Problem with Path Duration Limits

    DEFF Research Database (Denmark)

    Plum, Christian Edinger Munk; Pisinger, David; Salazar-González, Juan-José

    2012-01-01

    The design of container shipping networks is an important real world problem, with assets and operational costs in billions of dollars. To guide the optimal deployment of the ships, a single vessel roundtrip is considered by minimizing operational costs and flowing the best paying cargo under...... commercial constraints. Inspiration for formulation and solution method is taken from the rich research done within pickup and delivery problems. The problem, the multicommodity one-toone pickup and delivery traveling salesman problem with path duration limits is, to the best of out knowledge, considered...... for the first time. An arc flow and a path flow model are presented. A Branch and Cut and Price solution method is proposed and implemented....

  8. The effect of Fe and C in modifying deuterium pickup in Zr-2.5Nb: a response surface analysis

    International Nuclear Information System (INIS)

    Ploc, R.A.

    2001-03-01

    A Response Surface Analysis of the effect of iron and carbon in Zr-2.5Nb-Fe/C drop-castings has shown that iron and carbon have at least a quadratic, synergistic relationship on oxidation and deuterium pickup. Tests were performed in the Halden test reactor and associated autoclave for 208 days at 598 K (325 o C). The synergism explains why pressure tube data have limited value when attempting to deduce the effect of impurity elements on pick up. Out- and in-reactor pick up were similar in trend and magnitude except for the in-reactor deuterium pickup, which was about one-quarter of that out-reactor. Minimum in-reactor deuterium ingress is predicted for 30 ppm (wt) carbon and approximately 1,100 ppm (wt) of iron. Out-reactor optimal values are similar but with slightly higher iron values. (author)

  9. High-performance integrated pick-up circuit for SPAD arrays in time-correlated single photon counting

    Science.gov (United States)

    Acconcia, Giulia; Cominelli, Alessandro; Peronio, Pietro; Rech, Ivan; Ghioni, Massimo

    2017-05-01

    The analysis of optical signals by means of Single Photon Avalanche Diodes (SPADs) has been subject to a widespread interest in recent years. The development of multichannel high-performance Time Correlated Single Photon Counting (TCSPC) acquisition systems has undergone a fast trend. Concerning the detector performance, best in class results have been obtained resorting to custom technologies leading also to a strong dependence of the detector timing jitter from the threshold used to determine the onset of the photogenerated current flow. In this scenario, the avalanche current pick-up circuit plays a key role in determining the timing performance of the TCSPC acquisition system, especially with a large array of SPAD detectors because of electrical crosstalk issues. We developed a new current pick-up circuit based on a transimpedance amplifier structure able to extract the timing information from a 50-μm-diameter custom technology SPAD with a state-of-art timing jitter as low as 32ps and suitable to be exploited with SPAD arrays. In this paper we discuss the key features of this structure and we present a new version of the pick-up circuit that also provides quenching capabilities in order to minimize the number of interconnections required, an aspect that becomes more and more crucial in densely integrated systems.

  10. A Combination of Meta-heuristic and Heuristic Algorithms for the VRP, OVRP and VRP with Simultaneous Pickup and Delivery

    Directory of Open Access Journals (Sweden)

    Maryam Ashouri

    2017-07-01

    Full Text Available Vehicle routing problem (VRP is a Nondeterministic Polynomial Hard combinatorial optimization problem to serve the consumers from central depots and returned back to the originated depots with given vehicles. Furthermore, two of the most important extensions of the VRPs are the open vehicle routing problem (OVRP and VRP with simultaneous pickup and delivery (VRPSPD. In OVRP, the vehicles have not return to the depot after last visit and in VRPSPD, customers require simultaneous delivery and pick-up service. The aim of this paper is to present a combined effective ant colony optimization (CEACO which includes sweep and several local search algorithms which is different with common ant colony optimization (ACO. An extensive numerical experiment is performed on benchmark problem instances addressed in the literature. The computational result shows that suggested CEACO approach not only presented a very satisfying scalability, but also was competitive with other meta-heuristic algorithms in the literature for solving VRP, OVRP and VRPSPD problems. Keywords: Meta-heuristic algorithms, Vehicle Routing Problem, Open Vehicle Routing Problem, Simultaneously Pickup and Delivery, Ant Colony Optimization.

  11. Preliminary Specifications for the PS Pick-ups Amplifier to be used in the Transverse Damping System

    CERN Document Server

    Belleman, J; CERN. Geneva. AB Department

    2003-01-01

    The pick-up amplification stage to be used for the CODD in the PS is presently under redesign. It appears that the constraints for the circuit are very similar to those of the transverse feedback project. The AB/BDI group and in particular its PI section has kindly agreed to fulfil the RF group constraints so as to obtain a common design with a common control interface. The reliability aspect is not treated here. Nevertheless radiation has been considered. At the locations foreseen for the pick-ups (SS 2, 94, 98), the annual dose measured on the vacuum chamber (ref: CERN-TIS-2002-06-TE) is about 1000 Gray per year. This value is to be compared to the 100 Gy considered as the critical dose for electronic circuits. The radiation problem has been solved for the CODD pick-ups using distance and shield (active circuits 2 meters below the floor composed of concrete slabs). The same lay out will be applied for the dampers with the drawback of the capacitive plates being loaded with a low impedance -5 meters long- ca...

  12. Normative values and the effects of age, gender, and handedness on the Moberg Pick-Up Test.

    Science.gov (United States)

    Amirjani, Nasim; Ashworth, Nigel L; Gordon, Tessa; Edwards, David C; Chan, K Ming

    2007-06-01

    The Moberg Pick-Up Test is a standardized test for assessing hand dexterity. Although reduction of sensation in the hand occurs with aging, the effect of age on a subject's performance of the Moberg Pick-Up Test has not been examined. The primary goal of this study was to examine the impact of aging and, secondarily, the impact of gender and handedness, on performance of the Moberg Pick-Up Test in 116 healthy subjects. The average time to complete each of the four subsets of the test was analyzed using the Kruskal-Wallis, Mann-Whitney U, and Wilcoxon signed-rank tests. The results show that hand dexterity of the subjects was significantly affected by age, with young subjects being the fastest and elderly subjects the slowest. Women accomplished the test faster than men, and task performance with the dominant hand was faster than with the non-dominant hand. Use of normative values established based on age and gender is a valuable objective tool to gauge hand function in patients with different neurologic disorders.

  13. Reflective photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lentine, Anthony L.; Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Goeke, Ronald S.

    2018-03-06

    A photovoltaic module includes colorized reflective photovoltaic cells that act as pixels. The colorized reflective photovoltaic cells are arranged so that reflections from the photovoltaic cells or pixels visually combine into an image on the photovoltaic module. The colorized photovoltaic cell or pixel is composed of a set of 100 to 256 base color sub-pixel reflective segments or sub-pixels. The color of each pixel is determined by the combination of base color sub-pixels forming the pixel. As a result, each pixel can have a wide variety of colors using a set of base colors, which are created, from sub-pixel reflective segments having standard film thicknesses.

  14. Model based optimization of driver-pickup separation for eddy current measurement of gap

    Science.gov (United States)

    Klein, G.; Morelli, J.; Krause, T. W.

    2018-04-01

    The fuel channels in CANDU® (CANada Deuterium Uranium) nuclear reactors consist of a pressure tube (PT) contained within a larger diameter calandria tube (CT). The separation between the tubes, known as the PT-CT gap, ensures PT hydride blisters, which could lead to potential cracking of the PT, do not develop. Therefore, accurate measurements are required to confirm that contact between PT and CT is not imminent. Gap measurement uses an eddy current probe. However this probe is sensitive to lift-off variations, which can adversely affect estimated gap. A validated analytical flat plate model of eddy current response to gap was used to examine the effect of driver-pickup spacing on lift-off and response to gap at a frequency of 4 kHz, which is used for in-reactor measurements. This model was compared against, and shown to have good agreement with, a COMSOL® finite element method (FEM) model. The optimum coil separation, which included the constraint of coil size, was found to be 11 mm, resulting in a phase response between lift-off and response to change in gap of 66°. This work demonstrates the advantages of using analytical models for optimizing coil designs for measurement of parameters that may negatively influence the outcome of an inspection measurement.

  15. Critically safe volume vacuum pickup for use in wet or dry cleanup of radioactive enclosures

    International Nuclear Information System (INIS)

    Zeren, J.D.

    1993-01-01

    A physical compact vacuum pickup device of critically safe volume and geometric shape is provided for use in radioactive enclosures, such as a small glove box, to facilitate manual cleanup of either wet or dry radioactive material. The device is constructed and arranged so as to remain safe when filled to capacity with plutonium-239 oxide. Two fine mesh filter bags are supported on the exterior of a rigid fine mesh stainless steel cup. This assembly is sealed within, and spaced from, the interior walls of a stainless steel canister. An air inlet communicates with the interior of the canister. A modified conventional vacuum head is physically connected to, and associated with, the interior of the mesh cup. The volume of the canister, as defined by the space between the mesh cup and the interior walls of the canister, forms a critically safe volume and geometric shape for dry radioactive particles that are gathered within the canister. A critically safe liquid volume is maintained by operation of a suction terminating float valve, and/or by operation of redundant vacuum check/liquid drain valves and placement of the air inlet. 5 figures

  16. Testbeam Studies on Pick-Up in Sensors with Embedded Pitch Adapters

    CERN Document Server

    Rehnisch, Laura; The ATLAS collaboration

    2017-01-01

    For silicon strip sensors, the tracking information specifications can lead to challenging requirements for wire bonding. A common strategy is to use external pitch adapters to facilitate this step in the production of detector modules. A novel approach previously discussed in [1], is to implement the pitch adapters in the sensor, by embedding a second layer of metal tracks. The use of these embedded pitch adapters (EPAs) decouples the bond pad layout of the sensor from its implant layout by moving the adaption to the sensor production step. This solution, however, can yield the risk of performance losses due to the increase of inter-strip capacitance, or unwanted capacitive coupling between the metal layers (cross-talk) or the silicon bulk and the second metal layer (pick-up). In the prototyping stage of the ATLAS tracker end-cap upgrade, where different bond-pad layouts on sensor and readout chip lead to extremely challenging wire-bonding conditions, sensors with different geometries of EPA implementations ...

  17. Electron Cloud Buildup Characterization Using Shielded Pickup Measurements and Custom Modeling Code at CESRTA

    CERN Document Server

    Crittenden, James A

    2013-01-01

    The Cornell Electron Storage Ring Test Accelerator experimental program includes investigations into electron cloud buildup, applying various mitigation techniques in custom vacuum chambers. Among these are two 1.1-m-long sections located symmetrically in the east and west arc regions. These chambers are equipped with pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of small holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. Carbon-coated, TiN-coated and uncoated aluminum chambers have been tested. Electron and positron beams of 2.1, 4.0 and 5.3 GeV with a variety of bunch populations and spacings in steps of 4 and 14 ns have been used. Here we report on results from the ECLOUD modeling code which highlight the sensitivity of these measurements to the physical phenomena determining cloud buildup such as the photoelectron produ...

  18. Ship Routing with Pickup and Delivery for a Maritime Oil Transportation System: MIP Model and Heuristics

    Directory of Open Access Journals (Sweden)

    Vinícius P. Rodrigues

    2016-09-01

    Full Text Available This paper examines a ship routing problem with pickup and delivery and time windows for maritime oil transportation, motivated by the production and logistics activities of an oil company operating in the Brazilian coast. The transportation costs from offshore platforms to coastal terminals are an important issue in the search for operational excellence in the oil industry, involving operations that demand agile and effective decision support systems. This paper presents an optimization approach to address this problem, based on a mixed integer programming (MIP model and a novel and exploratory application of two tailor-made MIP heuristics, based on relax-and-fix and time decomposition procedures. The model minimizes fuel costs of a heterogeneous fleet of oil tankers and costs related to freighting contracts. The model also considers company-specific constraints for offshore oil transportation. Computational experiments based on the mathematical models and the related MIP heuristics are presented for a set of real data provided by the company, which confirm the potential of optimization-based methods to find good solutions for problems of moderate sizes.

  19. Longitudinal beam diagnostic from a distributed electrostatic pick-up in CERN's ELENA ring

    CERN Document Server

    Angoletta, M E; Federmann, S; Molendijk, J; Sanchez-Quesada, J; Secouet, P J; Søby, L; Pedersen, F; Timmins, M

    2013-01-01

    The CERN Extra Low ENergy Antiproton (ELENA) Ring is a new synchrotron that will be commissioned in 2016 to further decelerate the antiprotons coming from CERN’s Antiproton Decelerator (AD). Required longitudinal diagnostics include the intensity measurement for bunched and debunched beam and the measurement of Dp/p to assess the electron cooling performance. A novel method for the calculation of these parameters is proposed for ELENA, where signals from the twenty electrostatic Pick-Ups (PU) used for orbit measurements will be combined to improve the signal-to-noise ratio. This requires that the signals be digitally down-converted, rotated and summed so that the many electrostatic PUs will function as a single, distributed PU from the processing system viewpoint. This method includes some challenges and will not be used as the baseline longitudinal diagnostics for the initial ELENA operation. This paper gives an overview of the hardware and digital signal processing involved, as well as of the challenges t...

  20. Proton Heating by Pick-up Ion Driven Cyclotron Waves in the Outer Heliosphere: Hybrid Expanding Box Simulations

    Czech Academy of Sciences Publication Activity Database

    Hellinger, Petr; Trávníček, Pavel M.

    2016-01-01

    Roč. 832, č. 1 (2016), 32/1-32/7 ISSN 0004-637X Institutional support: RVO:67985815 Keywords : solar wind * instabilities * plasmas Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.533, year: 2016

  1. Proton heating by pick-up ion driven cyclotron waves in the outer heliosphere: Hybrid expanding box simulations

    Czech Academy of Sciences Publication Activity Database

    Hellinger, Petr; Trávníček, P. M.

    2016-01-01

    Roč. 832, č. 1 (2016) ISSN 0004-637X Institutional support: RVO:68378289 Keywords : solar wind * instabilities * plasmas Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 5.533, year: 2016 http://iopscience.iop.org/article/10.3847/0004-637X/832/1/32/pdf

  2. Calculation of deuterium retention in, re-emission and reflection from a tungsten material under D+ ions irradiation with ACAT-DIFFUSE

    International Nuclear Information System (INIS)

    Ono, T.; Muramoto, T.; Kenmotsu, T.; Kawamura, T.

    2008-08-01

    We calculated, with a dynamic Monte Carlo code ACAT-DIFFUSE, fluxes of thermal D 2 re-emission, reflection and self-sputtering from a wrought tungsten material during a time sequence of 100 eV D + implantation, post-implanted isothermal out-gassing and thermal desorption spectroscopy. The obtained result agreed well with an existing experiment, where diffusion was considered in the calculations from the beginning of implantation. The three fluxes in the implantation period were shown to be almost comparable. The integrated deuterium flux released in the same period was estimated. The depth profiles of deuterium retained at 300 K in that period indicate that, while their maximum locations did not move, the profiles were broadened out because of fast diffusion. The amount of deuterium retained at 300 K was one order of magnitude higher than that at 473 K. (author)

  3. Enhanced Schottky signals from electron-cooled, coasting beams in a heavy-ion storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, C., E-mail: claude.krantz@mpi-hd.mpg.d [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Blaum, K.; Grieser, M. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Litvinov, Yu.A. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany); Repnow, R.; Wolf, A. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2011-02-11

    Measurements at the Test Storage Ring of the Max-Planck-Institut fuer Kernphysik in Heidelberg (Germany) have shown that the signal amplitude induced in a Schottky-noise pickup electrode by a coasting electron-cooled ion beam can be greatly enhanced by exposure of the latter to a perturbing radiofrequency signal which is detuned from the true beam revolution frequency. The centre frequencies obtained from harmonic analysis of the observed pickup signal closely follow those imposed on the ions by the electron cooling force. The phenomenon can be exploited to measure the true revolution frequency of ion beams of very low intensity, whose pure Schottky noise is too weak to be measurable under normal circumstances.

  4. Gamma irradiation testing of prototype ITER in-vessel magnetic pick-up coils

    International Nuclear Information System (INIS)

    Vermeeren, Ludo; Leysen, Willem

    2013-01-01

    Highlights: ► We tested five prototype ITER in-vessel coils up to a gamma dose of 72 MGy. ► Before and after irradiation thermal tests were also performed from 30 °C till 130 °C. ► The continuity resistances and the insulation resistances were continuously monitored. ► The observed behavior of all coils was satisfactory in all conditions. ► For the further design the mechanical robustness should be taken into account. -- Abstract: To fulfill the requirements for ITER in-vessel magnetic diagnostics, several coil prototypes have been developed, aiming at minimizing the disturbing effects of temperature gradients and radiation induced phenomena. As a first step in the radiation resistance testing of these prototypes, an in-situ high dose rate gamma radiation test on a selection of prototypes was performed. The aim of this test was to get a first experimental feedback regarding the behavior of the pick-up coil prototypes under radiation. Five prototypes (a coil wound with glass-insulated copper wire, two LTCC coils and two HTCC coils) were irradiated at a dose rate of 46 kGy/h up to a total dose of 72 MGy and at a temperature of 50 °C. During the irradiation, the continuity resistances and the insulation resistances were continuously measured. Before and after irradiation reference data were recorded as a function of temperature (from 30 °C to 130 °C). This paper includes the results of the temperature and irradiation tests and a discussion of the behavior of the prototype coils in terms of electrical and mechanical properties

  5. Minimum pickup velocity (U{sub pu}) of nanoparticles in gas–solid pneumatic conveying

    Energy Technology Data Exchange (ETDEWEB)

    Anantharaman, Aditya [Nanyang Technological University, School of Chemical and Biomedical Engineering (Singapore); Ommen, J. Ruud van [Delft University of Technology, Department of Chemical Engineering (Netherlands); Chew, Jia Wei, E-mail: JChew@ntu.edu.sg [Nanyang Technological University, School of Chemical and Biomedical Engineering (Singapore)

    2015-12-15

    This paper is the first systematic study of the pneumatic conveying of nanoparticles. The minimum pickup velocity, U{sub pu}, of six nanoparticle species of different materials [i.e., silicon dioxide (SiO{sub 2}), aluminum oxide (Al{sub 2}O{sub 3}), and titanium dioxide (TiO{sub 2})] and surfaces (i.e., apolar and polar) was determined by the weight loss method. Results show that (1) due to relative lack of hydrogen bonding, apolar nanoparticles had higher mass loss values at the same velocities, mass loss curves with accentuated S-shaped profiles, and lower U{sub pu} values, (2) among the three species, SiO{sub 2}, which has the lowest Hamaker coefficient, exhibited the greatest discrepancy between apolar and polar surfaces with respect to both mass loss curves and U{sub pu} values, (3) U{sub mf,polar}/U{sub mf,apolar} was between 1 and 3.5 times that of U{sub pu,polar}/U{sub pu,apolar} due to greater extents of hydrogen bonding associated with U{sub mf}, (4) U{sub pu} values were at least an order-of-magnitude lower than that expected from the well-acknowledged U{sub pu} correlation (Kalman et al., Powder Technol 160:103–113, 2005) due to agglomeration, (5) although nanoparticles should be categorized as Zone III (Kalman et al. 2005) (or Geldart group C, Powder Technol 7:285–292, 1973), the nanoparticles, and primary and complex agglomerates agreed more with the Zone I (or Geldart group B) correlation.

  6. Sub-cellular Electrical Heterogeneity Revealed by Loose Patch Recording Reflects Differential Localization of Sarcolemmal Ion Channels in Intact Rat Hearts

    Directory of Open Access Journals (Sweden)

    Igor V. Kubasov

    2018-02-01

    Full Text Available The cardiac action potential (AP is commonly recoded as an integral signal from isolated myocytes or ensembles of myocytes (with intracellular microelectrodes and extracellular macroelectrodes, respectively. These signals, however, do not provide a direct measure of activity of ion channels and transporters located in two major compartments of a cardiac myocyte: surface sarcolemma and the T-tubule system, which differentially contribute to impulse propagation and excitation-contraction (EC coupling. In the present study we investigated electrical properties of myocytes within perfused intact rat heart employing loose patch recording with narrow-tip (2 μm diameter extracellular electrodes. Using this approach, we demonstrated two distinct types of electric signals with distinct waveforms (single peak and multi-peak AP; AP1 and AP2, respectively during intrinsic pacemaker activity. These two types of waveforms depend on the position of the electrode tip on the myocyte surface. Such heterogeneity of electrical signals was lost when electrodes of larger pipette diameter were used (5 or 10 μm, which indicates that the electric signal was assessed from a region of <5 μm. Importantly, both pharmacological and mathematical simulation based on transverse (T-tubular distribution suggested that while the AP1 and the initial peak of AP2 are predominantly attributable to the fast, inward Na+ current in myocyte's surface sarcolemma, the late components of AP2 are likely representative of currents associated with L-type Ca2+ channel and Na+/Ca2+ exchanger (NCX currents which are predominantly located in T-tubules. Thus, loose patch recording with narrow-tip pipette provides a valuable tool for studying cardiac electric activity on the subcellular level in the intact heart.

  7. Personal Reflections

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Personal Reflections. Articles in Resonance – Journal of Science Education. Volume 6 Issue 3 March 2001 pp 90-93 Personal Reflections. Why did I opt for Career in Science? Jayant V Narlikar · More Details Fulltext PDF. Volume 9 Issue 8 August 2004 pp 89-89 ...

  8. Reflection groups

    International Nuclear Information System (INIS)

    Eggermont, G.

    2006-01-01

    In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward

  9. Reflection ciphers

    DEFF Research Database (Denmark)

    Boura, Christina; Canteaut, Anne; Knudsen, Lars Ramkilde

    2017-01-01

    study the necessary properties for this coupling permutation. Special care has to be taken of some related-key distinguishers since, in the context of reflection ciphers, they may provide attacks in the single-key setting.We then derive some criteria for constructing secure reflection ciphers...

  10. Quantifying Reflection

    DEFF Research Database (Denmark)

    Alcock, Gordon Lindsay

    2013-01-01

    ´ These are all based on Blooms taxonomy and levels of competence and form a major part of individual student and group learning portfolios. Key Words :Project-Based learning, Reflective Portfolios, Self assessment, Defining learning gains, Developing learning strategies , Reflections on and for learning....... It contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning......This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark...

  11. Listing of 502 Times When the Ulysses Magnetic Fields Instrument Observed Waves Due to Newborn Interstellar Pickup Protons

    International Nuclear Information System (INIS)

    Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

    2017-01-01

    In two earlier publications we analyzed 502 intervals of magnetic waves excited by newborn interstellar pickup protons that were observed by the Ulysses spacecraft. Due to the considerable effort required in identifying these events, we provide a list of the times for the 502 wave event intervals previously identified. In the process, we provide a brief description of how the waves were found and what their properties are. We also remind the reader of the conditions that permit the waves to reach observable levels and explain why the waves are not seen more often.

  12. Micromanipulation and pick-up system for X-Ray diffraction characterization of micrometer-sized single particles

    International Nuclear Information System (INIS)

    Takeichi, Y; Inami, N; Saito, K; Otori, H; Sagayama, R; Kumai, R; Ono, K; Ueno, T

    2014-01-01

    We describe a micromanipulation and pick-up system for preparing a micrometer-sized single particle for X-ray diffraction characterization. Combining a microgripper based on microelectromechanical systems, piezo-motor-driven linear stages, and a gamepad, the system provides precise and intuitive handling of the object. Single-crystal X-ray diffraction measurements of Sm-Fe-N permanent magnet were performed using this system. We also describe a method to distinguish crystallographically homogeneous particles found in powder-form samples.

  13. Vehicle Routing Problem with Time Windows and Simultaneous Delivery and Pick-Up Service Based on MCPSO

    Directory of Open Access Journals (Sweden)

    Xiaobing Gan

    2012-01-01

    Full Text Available This paper considers two additional factors of the widely researched vehicle routing problem with time windows (VRPTW. The two factors, which are very common characteristics in realworld, are uncertain number of vehicles and simultaneous delivery and pick-up service. Using minimization of the total transport costs as the objective of the extension VRPTW, a mathematic model is constructed. To solve the problem, an efficient multiswarm cooperative particle swarm optimization (MCPSO algorithm is applied. And a new encoding method is proposed for the extension VRPTW. Finally, comparing with genetic algorithm (GA and particle swarm optimization (PSO algorithm, the MCPSO algorithm performs best for solving this problem.

  14. The Hydrogen Pickup Behavior for Zirconium-based Alloys in Various Out-of-pile Corrosion Test Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aomi, M.; Etoh, Y.; Ishimoto, S.; Une, K. [Nippon Nuclear Fuel Development, Co., Ltd., 2163 Narita-cho, Oarai-machi, Ibaraki-ken, 311-1313 (Japan); Ito, K. [Global Nuclear Fuel Japan Co., Ltd., 3-1 Uchikawa 2-chome, Yokosuka-shi, Kanagawa-ken, 239-0836 (Japan)

    2009-06-15

    An acceleration of hydrogen absorption in zirconium alloy claddings at high burnups is one of the most important issues limiting the fuel performance from the viewpoint of cladding integrity. In this context, advanced cladding materials with higher corrosion resistant and lower hydrogen absorption properties have been widely searched in various organizations. In this study, four kinds of zirconium-based alloys, whose in-pile data had been acquired [1,2] were subjected to comprehensive out-of-pile corrosion tests with various temperature and atmosphere conditions in order to investigate the correlation between in-pile and out-of-pile corrosion and hydrogen pick-up behavior, i.e. Zry-2, GNF-Ziron (Zry-2-based alloy with {approx}0.25 wt % of Fe), Hi-FeNi Zircaloy (Zry-2-based alloy with {approx}0.25 wt % of Fe and {approx}0.1 wt% Ni), and VB (Zr-based alloy containing Sn, Cr, and {approx}0.5 wt % of Fe). All the alloys were annealed in RXA condition. The out-of-pile corrosion tests were carried out in three different conditions of 400 deg. C steam, 475 deg. C supercritical water, and 290 deg. C LiOH aqueous solution. In addition to these alloys, several Zry-2-based alloys with various iron contents were tested in 290 deg. C LiOH aqueous solution. Among the four corrosion conditions, the 290 deg. C LiOH aqueous solution test well screened the hydrogen pick-up behavior of the alloys. The hydrogen absorption decreased with higher iron contents in the alloys in both the out-of-pile and in-pile conditions. Especially, the distinct suppression of hydrogen absorption was observed for VB with the highest iron content. The similar dependence of iron content on the hydrogen pick-up fraction was also obtained for the Zry-2-based alloys with different iron contents, which were corroded in the 290 deg. C LiOH aqueous solution condition. As for the corrosion behavior in the 290 deg. C LiOH aqueous solution condition, the weight gains of Zry-2, GNF-Ziron and VB followed the 1

  15. Listing of 502 Times When the Ulysses Magnetic Fields Instrument Observed Waves Due to Newborn Interstellar Pickup Protons

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, Florida (United States); Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire (United States); Murphy, Neil [Jet Propulsion Laboratory, Mail Stop 180-600, 4800 Oak Grove Drive, Pasadena, California (United States); Nuno, Raquel G., E-mail: bc13h@my.fsu.edu, E-mail: Charles.Smith@unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: Colin.Joyce@unh.edu, E-mail: Neil.Murphy@jpl.nasa.gov, E-mail: rgnuno@ucla.edu [Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA (United States)

    2017-05-01

    In two earlier publications we analyzed 502 intervals of magnetic waves excited by newborn interstellar pickup protons that were observed by the Ulysses spacecraft. Due to the considerable effort required in identifying these events, we provide a list of the times for the 502 wave event intervals previously identified. In the process, we provide a brief description of how the waves were found and what their properties are. We also remind the reader of the conditions that permit the waves to reach observable levels and explain why the waves are not seen more often.

  16. Two-proton pickup studies with the (6Li,8B) reaction

    Energy Technology Data Exchange (ETDEWEB)

    Weisenmiller, R.B.

    1976-12-03

    The (/sup 6/Li,/sup 8/B) reaction has been investigated on targets of /sup 26/Mg, /sup 24/Mg, /sup 16/O, /sup 13/C, /sup 12/C, /sup 11/B, /sup 10/B, and /sup 9/Be at a bombarding energy of 80.0 MeV, and on targets of /sup 16/O, /sup 12/C, /sup 9/Be, /sup 7/Li, and /sup 6/Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this reaction resembles that of the analogous (p,t) reaction. Additionally, these data demonstrate the dominance of spatially symmetric transfer of the two protons. On T/sub z/ greater than 0 targets the (/sup 6/Li,/sup 8/B) reaction was employed to locate two previously unreported levels (at 7.47 +- 0.05 MeV and 8.86 +- 0.07 MeV) in the T/sub z/ = 2 nuclide /sup 24/Ne and to establish the low-lying 1p-shell states in the T/sub z/ = /sup 3///sub 2/ nuclei /sup 11/Be, /sup 9/Li, and /sup 7/He. However, no evidence was seen for any narrow levels in the T/sub z/ = /sup 3///sub 2/ nuclide /sup 5/H nor for any narrow excited states in /sup 7/He. The angular distributions reported here are rather featureless and decrease monotonically with increasing angle. This behavior can be shown by a semi-classical reaction theory to be a consequence of the reaction kinematics. A semi-classical approach also suggests that the kinematic term in the transition matrix element is only weakly dependent upon the angular momentum transfer (which is consistent with simple Distorted Wave Born Approximation calculations). However, only qualitative agreement was obtained between the observed relative transition yields and semi-classical predictions, using the two-nucleon coefficients of fractional parentage of Cohen and Kurath, probably due to the limitations of the semi-classical reaction theory.

  17. Two-proton pickup studies with the (6Li,8B) reaction

    International Nuclear Information System (INIS)

    Weisenmiller, R.B.

    1976-01-01

    The ( 6 Li, 8 B) reaction has been investigated on targets of 26 Mg, 24 Mg, 16 O, 13 C, 12 C, 11 B, 10 B, and 9 Be at a bombarding energy of 80.0 MeV, and on targets of 16 O, 12 C, 9 Be, 7 Li, and 6 Li at a bombarding energy of 93.3 MeV. Only levels consistent with direct, single-step two-proton pickup reaction mechanisms were observed to be strongly populated. On T/sub z/ = 0 targets, the spectroscopic selectivity of this reaction resembles that of the analogous (p,t) reaction. Additionally, these data demonstrate the dominance of spatially symmetric transfer of the two protons. On T/sub z/ greater than 0 targets the ( 6 Li, 8 B) reaction was employed to locate two previously unreported levels (at 7.47 +- 0.05 MeV and 8.86 +- 0.07 MeV) in the T/sub z/ = 2 nuclide 24 Ne and to establish the low-lying 1p-shell states in the T/sub z/ = 3 / 2 nuclei 11 Be, 9 Li, and 7 He. However, no evidence was seen for any narrow levels in the T/sub z/ = 3 / 2 nuclide 5 H nor for any narrow excited states in 7 He. The angular distributions reported here are rather featureless and decrease monotonically with increasing angle. This behavior can be shown by a semi-classical reaction theory to be a consequence of the reaction kinematics. A semi-classical approach also suggests that the kinematic term in the transition matrix element is only weakly dependent upon the angular momentum transfer (which is consistent with simple Distorted Wave Born Approximation calculations). However, only qualitative agreement was obtained between the observed relative transition yields and semi-classical predictions, using the two-nucleon coefficients of fractional parentage of Cohen and Kurath, probably due to the limitations of the semi-classical reaction theory

  18. Reflectance Modeling

    Science.gov (United States)

    Smith, J. A.; Cooper, K.; Randolph, M.

    1984-01-01

    A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.

  19. Automatic detection of lift-off and touch-down of a pick-up walker using 3D kinematics.

    Science.gov (United States)

    Grootveld, L; Thies, S B; Ogden, D; Howard, D; Kenney, L P J

    2014-02-01

    Walking aids have been associated with falls and it is believed that incorrect use limits their usefulness. Measures are therefore needed that characterize their stable use and the classification of key events in walking aid movement is the first step in their development. This study presents an automated algorithm for detection of lift-off (LO) and touch-down (TD) events of a pick-up walker. For algorithm design and initial testing, a single user performed trials for which the four individual walker feet lifted off the ground and touched down again in various sequences, and for different amounts of frame loading (Dataset_1). For further validation, ten healthy young subjects walked with the pick-up walker on flat ground (Dataset_2a) and on a narrow beam (Dataset_2b), to challenge balance. One 88-year-old walking frame user was also assessed. Kinematic data were collected with a 3D optoelectronic camera system. The algorithm detected over 93% of events (Dataset_1), and 95% and 92% in Dataset_2a and b, respectively. Of the various LO/TD sequences, those associated with natural progression resulted in up to 100% correctly identified events. For the 88-year-old walking frame user, 96% of LO events and 93% of TD events were detected, demonstrating the potential of the approach. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Reflective optics

    CERN Document Server

    Korsch, Dietrich

    1991-01-01

    This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc

  1. Negative ion sources

    International Nuclear Information System (INIS)

    Ishikawa, Junzo; Takagi, Toshinori

    1983-01-01

    Negative ion sources have been originally developed at the request of tandem electrostatic accelerators, and hundreds of nA to several μA negative ion current has been obtained so far for various elements. Recently, the development of large current hydrogen negative ion sources has been demanded from the standpoint of the heating by neutral particle beam injection in nuclear fusion reactors. On the other hand, the physical properties of negative ions are interesting in the thin film formation using ions. Anyway, it is the present status that the mechanism of negative ion action has not been so fully investigated as positive ions because the history of negative ion sources is short. In this report, the many mechanisms about the generation of negative ions proposed so far are described about negative ion generating mechanism, negative ion source plasma, and negative ion generation on metal surfaces. As a result, negative ion sources are roughly divided into two schemes, plasma extraction and secondary ion extraction, and the former is further classified into the PIG ion source and its variation and Duoplasmatron and its variation; while the latter into reflecting and sputtering types. In the second half of the report, the practical negative ion sources of each scheme are described. If the mechanism of negative ion generation will be investigated more in detail and the development will be continued under the unified know-how as negative ion sources in future, the development of negative ion sources with which large current can be obtained for any element is expected. (Wakatsuki, Y.)

  2. Analysis of trace and mineral elements in vanilla pods from the region of S.A.V.A using total reflection X-ray fluorescence, atomic absorption and ion chromatography techniques

    International Nuclear Information System (INIS)

    Be, K.

    2013-01-01

    In the case of studies of food security, - arsenic, cobalt, chromium, copper, iron, manganese, nickel, rubidium, selenium, strontium, titanium, zinc - cadmium, lead - are almost always analyzed. Guide values are used to express the level of quality in matter of consumption. Analytical laboratories of Madagascar-INSTN outline usually their research on quantifying those elements by using two different analytical methods, the Total Reflection X-Ray Fluorescence for the first twelve metals and the Atomic Absorption Spectrometry dedicated to lead and cadmium. Supplementary analysis is carried out for the quantification of essential mineral elements such as calcium, magnesium and potassium by using Ion Chromatograph. The aim of this study was to set up the analysis of the above mentioned elements in vanilla pods collected from Sambava, Antalaha and Andapa for a routine use. After all the parameters were established, the validation was particularly focused on the limits of detection and quantification and the accuracy of each element. The used methods fulfil the scope of application needed and are easy to use in routine. [fr

  3. Developments at an electrostatic cryogenic storage ring for electron-cooled keV energy ion beams

    International Nuclear Information System (INIS)

    Vogel, Stephen

    2016-01-01

    This work is devoted to final setup activities and the commissioning of an electrostatic cryogenic storage ring (CSR) at the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg. The first cryogenic operation of CSR in 2015 has been documented and characterized using a set of non-destructive beam diagnostic tools developed within this work. These are (1) the current pick-up system for the determination of the current of the stored ion beam and its velocity, (2) a position pick-up system for measuring the transverse position of the ion beam center at six symmetric locations of the storage ring circumference, and (3) a Schottky pick-up system for the monitoring of coasting ion beams. Despite the requirements imposed by the cryogenic operation, the developed diagnostic system demonstrated its full functionality. First characterizations of the storage ring properties and the performance of the diagnostic system are presented. Based on previous work, an electron cooling system for CSR has been developed and largely realized. With the implementation into CSR in 2016, the electron cooler will enhance the storage ring into a unique experimental facility for electron-ion collision studies. With this CSR is on the track to become the first cryogenic storage ring featuring actively cooled ion beams.

  4. Reflective Efficacy

    Directory of Open Access Journals (Sweden)

    Carla Bagnoli

    2018-04-01

    Full Text Available The purpose of this paper is to highlight some difficulties of Neil Sinhababu’s Humean theory of agency, which depend on his radically reductivist approach, rather than to his Humean sympathies. The argument is that Sinhababu’s theory builds upon a critique of reflective agency which is based on equivocation and misunderstandings of the Kantian approach. Ultimately, the objection is that his reductivist view is unequipped to address the rclassical problems of rational deliberation and agential authority.

  5. Trajectory bending and energy spreading of charged ions in time-of-flight telescopes used for ion beam analysis

    International Nuclear Information System (INIS)

    Laitinen, Mikko; Sajavaara, Timo

    2014-01-01

    Carbon foil time pick-up detectors are widely used in pairs in ion beam applications as time-of-flight detectors. These detectors are suitable for a wide energy range and for all ions but at the lowest energies the tandem effect limits the achievable time of flight and therefore the energy resolution. Tandem effect occurs when an ion passes the first carbon foil of the timing detector and its charge state is changed. As the carbon foil of the first timing detector has often a non-zero voltage the ion can accelerate or decelerate before and after the timing detector. The combination of different charge state properties before and after the carbon foil now induces spread to the measured times of flight. We have simulated different time pick-up detector orientations, voltages, ions and ion energies to examine the tandem effect in detail and found out that the individual timing detector orientation and the average ion charge state have a very small influence to the magnitude of the tandem effect. On the other hand, the width of the charge state distribution for particular ion and energy in the first carbon foil, and the carbon foil voltage contributes linearly to the magnitude of the tandem effect. In the simulations low energy light ion trajectories were observed to bend in the electric fields of the first timing gate, and the magnitude of this bending was studied. It was found out that 50–150 keV proton trajectories can even bend outside the second timing gate

  6. Integration of agglutination assay for protein detection in microfluidic disc using Blu-ray optical pickup unit and optical fluid scanning

    DEFF Research Database (Denmark)

    Uddin, Rokon; Burger, Robert; Donolato, Marco

    2015-01-01

    We present a novel strategy for thrombin detection by combining a magnetic bead based agglutination assay and low-cost microfluidic disc. The detection method is based on an optomagnetic readout system implemented using a Blu-ray optical pickup unit (OPU) as main optoelectronic component. The ass...

  7. On Reflection

    DEFF Research Database (Denmark)

    Blasco, Maribel

    2012-01-01

    produces: that the self is accessible and transcendable, that reflexivity is universal across space and time, and that the self can act as its own remedial change agent or ‘inner consultant.’ I argue that because reflexivity is understood in many different ways, attention to definition is crucial, both...... on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view...

  8. Inspiring Reflections

    DEFF Research Database (Denmark)

    Muchie, Mammo

    2011-01-01

    A numberof Chris Freeman's colleagues were asked to reflect on what they thought describes his life and work in a few words. Some of the colleagues replied including former SPRU students that were taught or supervised by Chris Freeman. Their views on what they thought were Chris Freeman's defining...... life is not free from fluctuations, cycles, disruptions, crises and destructions both human and ecological. Innovation research ought to position itself to address environmental, financial and economic crises. The third is innovation research for development by addressing not only poverty erdaication...

  9. Reflective Writing

    DEFF Research Database (Denmark)

    Ahrenkiel Jørgensen, Andriette

    2016-01-01

    In Breve fra min Have (Letters from my Garden), the Swedish landscape architect, Sven-Ingvar Andersson, produces dialogues about his garden to a wide circle of friends, colleagues, deceased and still living acquaintances such as Karen Blixen, Gertrude Stein, C. Th. Sørensen, Albrecht Dürer, Peter...... Høeg etetera. The dialogues work as a tool of reflection in terms of providing opportunity to examine his own beliefs, to explore the possible reasons for engaging in a particular activity. On the basis of Sven-Ingvar Andersson’s book a teaching program at the Aarhus School of Architecture provides...

  10. Reflective Packaging

    Science.gov (United States)

    1994-01-01

    The aluminized polymer film used in spacecraft as a radiation barrier to protect both astronauts and delicate instruments has led to a number of spinoff applications. Among them are aluminized shipping bags, food cart covers and medical bags. Radiant Technologies purchases component materials and assembles a barrier made of layers of aluminized foil. The packaging reflects outside heat away from the product inside the container. The company is developing new aluminized lines, express mailers, large shipping bags, gel packs and insulated panels for the building industry.

  11. Proton pickup from /sup 27/Al via the (n,d) reaction at 56. 3 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Brady, F P; Shepard, J R; King, N S.P.; McNaughton, M W; Wang, J C [California Univ., Davis (USA)

    1977-09-26

    Energy spectra of deuterons from the /sup 27/Al(n,d)/sup 26/Mg reaction due to 56.3 MeV neutrons incident have been measured for 10/sup 0/ <= thetasub(c.m.) <= 55 /sup 0/. The angular distributions for the excitations observed at 0.0, 1.81, and 4.33 MeV are quite well described by DWBA calculations and yield spectroscopic factors in agreement with shell model calculations; but with calculations based on the rotational model, the agreement is less satisfactory particularly for the 4.33 MeV level. For the states at 7.86 and 9.16 MeV the fits, assuming p-shell pick-up, are only fair. Comparison with /sup 27/Al(d,/sup 3/He)/sup 26/Mg measurements shows that the deduced spectroscopic factors for the two reactions agree quite well.

  12. Design of a PC Based Pressure Indicator Using Inductive Pick-up Type Transducer and Bourdon Tube Sensor

    Directory of Open Access Journals (Sweden)

    S. C. BERA

    2009-08-01

    Full Text Available Bourdon tube is a mechanical type pressure sensor and the bourdon gauge measures gauge pressure of a process pipe line or a process tank. But it is a local indicator and special costlier techniques are required to transmit the reading of bourdon gauge to a remote distance. In the present paper, a very simple inductive pick-up type technique has been developed to transmit the reading of bourdon gauge to a remote distance in the form of 1-5 Volt D.C. signal. This signal has been optically isolated to design a PC based pressure indicator using Labtech Note Book Pro software. The theoretical analysis of the whole technique has been presented in the paper. The instrument developed using this technique has been experimentally tested and the experimental results are reported in the paper. A good linearity and repeatability of the instrument has been observed.

  13. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  14. HTS planar gradiometer consisting of SQUID with multi-turn input coil and large pickup coil made of GdBCO coated conductor

    International Nuclear Information System (INIS)

    Tsukamoto, Akira; Adachi, Seiji; Oshikubo, Yasuo; Hato, Tsunehiro; Enpuku, Keiji; Sugisaki, Masaki; Arai, Eiichi; Tanabe, Keiichi

    2013-01-01

    Highlights: ► We fabricated a large HTS gradiometer with 350-mm-long baseline. ► A 6-turn gradiometric planar pickup was made of a HTS coated conductor. ► A 26-turn HTS input coil chip was stacked on a HTS thin film gradiometer chip. ► A mechanical balancing structure was also implemented. ► The fabricated gradiometer showed a gradient field noise of 0.8 fT/cm Hz 1/2 . -- Abstract: We have investigated the fabrication of a high-temperature superconducting (HTS) gradiometer with long baseline for geophysical applications. The proof-of-concept gradiometer using a 1-turn pickup coil made of a GdBa 2 Cu 3 O y coated conductor (GCC) and 5.5-turn input coil integrated on a SQUID was fabricated in our previous work. In this study, we have optimized the device structure to improve the frequency response, gradient field sensitivity and gradiometer balance. The fabricated flux transformer consists of a 6-turn planar gradiometric pickup coil and a 26-turn input coil made of an HTS thin film. A low-melting-point alloy was used to connect polished Ag surfaces of the CGG pickup coil and Au pads of the input coil. An HTS SQUID was formed on another substrate and stacked on the input coil. A mechanical balancing structure using three pieces of GCC as a superconducting shield was also implemented. The fabricated gradiometer showed a gradient field noise of 0.8 fT/cm Hz 1/2 in the white noise regions, a gradiometer balance of 1/142, and a cutoff frequency of 9 Hz corresponding to a 2 mΩ contact resistance between the pickup coil and the input coil

  15. Cometary water-group ions in the region surrounding Comet Giacobini-Zinner - Distribution functions and bulk parameter estimates

    Science.gov (United States)

    Staines, K.; Balogh, A.; Cowley, S. W. H.; Richardson, I. G.; Sanderson, T. R.; Tsurutani, B. T.

    1991-01-01

    The bulk parameters (number density and thermal energy density) of cometary water-group ions in the region surrounding Comet Giacobini-Zinner have been derived using data from the EPAS instrument on the ICE spacecraft. The derivation is based on the assumption that the pick-up ion distribution function is isotropic in the frame of the bulk flow, an approximation which has previously been shown to be reasonable within about 400,000 km of the comet nucleus along the spacecraft trajectory. The transition between the pick-up and mass-loaded regions occurs at the cometary shock, which was traversed at a cometocentric distance of about 100,000 km along the spacecraft track. Examination of the ion distribution functions in this region, transformed to the bulk flow frame, indicates the occurrence of a flattened distribution in the vicinity of the local pick-up speed, and a steeply falling tail at speeds above, which may be approximated as an exponential in ion speed.

  16. Simulated orbits of heavy planetary ions at Mars for different IMF configurations

    Science.gov (United States)

    Curry, Shannon; Luhmann, Janet; Livi, Roberto; Hara, Takuya; Dong, Chuanfei; Ma, Yingjuan; McFadden, James; Bougher, Stephen

    2014-11-01

    We present simulated detections of O+, O2+ and CO2+ ions at Mars along a virtual orbit in the Mars space environment. Planetary pick-up ions are formed through the direct interaction of the solar wind with the neutral upper atmosphere, causing the newly created ions to be picked up and accelerated by the background convective electric field. Because previous missions such as Mars Global Surveyor (MGS) and Mars Express (MEX) have not been able to measure the interplanetary magnetic field (IMF) components simultaneously with plasma measurements, the response of heavy planetary pick-up ions to changes in the IMF has not been well characterized. Using a steady-state multi-species MHD model to provide the background electric and magnetic fields, the Mars Test Particle (MTP) simulation can trace each of these particles along field lines in near-Mars space and construct virtual ion detections from a spacecraft orbit. Specifically, we will present energy-time spectrograms and velocity space distributions (VSDs) for a selection of orbits during different IMF configurations and solar cycle conditions. These simulated orbits have broader implications for how to measure ion escape. Using individual particle traces, the origin and trajectories of different ion populations can be analyzed in order to assess how and where they contribute to the total atmospheric escape rate, which is a major objective of the upcoming MAVEN mission.

  17. Reflected Glory

    Science.gov (United States)

    2011-02-01

    The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and

  18. Ion-ion collisions

    International Nuclear Information System (INIS)

    Salzborn, Erhard; Melchert, Frank

    2000-01-01

    Collisions between ions belong to the elementary processes occurring in all types of plasmas. In this article we give a short overview about collisions involving one-electron systems. For collisions involving multiply-charged ions we limit the discussion to one specific quasi-one-electron system. (author)

  19. MAVEN Observations of Escaping Planetary Ions from the Martian Atmosphere: Mass, Velocity, and Spatial Distributions

    Science.gov (United States)

    Dong, Yaxue; Fang, Xiaohua; Brain, D. A.; McFadden, James P.; Halekas, Jasper; Connerney, Jack

    2015-04-01

    The Mars-solar wind interaction accelerates and transports planetary ions away from the Martian atmosphere through a number of processes, including ‘pick-up’ by electromagnetic fields. The MAVEN spacecraft has made routine observations of escaping planetary ions since its arrival at Mars in September 2014. The SupraThermal And Thermal Ion Composition (STATIC) instrument measures the ion energy, mass, and angular spectra. It has detected energetic planetary ions during most of the spacecraft orbits, which are attributed to the pick-up process. We found significant variations in the escaping ion mass and velocity distributions from the STATIC data, which can be explained by factors such as varying solar wind conditions, contributions of particles from different source locations and different phases during the pick-up process. We also study the spatial distributions of different planetary ion species, which can provide insight into the physics of ion escaping process and enhance our understanding of atmospheric erosion by the solar wind. Our results will be further interpreted within the context of the upstream solar wind conditions measured by the MAVEN Solar Wind Ion Analyzer (SWIA) instrument and the magnetic field environment measured by the Magnetometer (MAG) instrument. Our study shows that the ion spatial distribution in the Mars-Sun-Electric-Field (MSE) coordinate system and the velocity space distribution with respect to the local magnetic field line can be used to distinguish the ions escaping through the polar plume and those through the tail region. The contribution of the polar plume ion escape to the total escape rate will also be discussed.

  20. Comparative study of ion cyclotron waves at Mars, Venus and Earth

    Science.gov (United States)

    Wei, H. Y.; Russell, C. T.; Zhang, T. L.; Blanco-Cano, X.

    2011-08-01

    Ion cyclotron waves are generated in the solar wind when it picks up freshly ionized planetary exospheric ions. These waves grow from the free energy of the highly anisotropic distribution of fresh pickup ions, and are observed in the spacecraft frame with left-handed polarization and a wave frequency near the ion's gyrofrequency. At Mars and Venus and in the Earth's polar cusp, the solar wind directly interacts with the planetary exospheres. Ion cyclotron waves with many similar properties are observed in these diverse plasma environments. The ion cyclotron waves at Mars indicate its hydrogen exosphere to be extensive and asymmetric in the direction of the interplanetary electric field. The production of fast neutrals plays an important role in forming an extended exosphere in the shape and size observed. At Venus, the region of exospheric proton cyclotron wave production may be restricted to the magnetosheath. The waves observed in the solar wind at Venus appear to be largely produced by the solar-wind-Venus interaction, with some waves at higher frequencies formed near the Sun and carried outward by the solar wind to Venus. These waves have some similarity to the expected properties of exospherically produced proton pickup waves but are characterized by magnetic connection to the bow shock or by a lack of correlation with local solar wind properties respectively. Any confusion of solar derived waves with exospherically derived ion pickup waves is not an issue at Mars because the solar-produced waves are generally at much higher frequencies than the local pickup waves and the solar waves should be mostly absorbed when convected to Mars distance as the proton cyclotron frequency in the plasma frame approaches the frequency of the solar-produced waves. In the Earth's polar cusp, the wave properties of ion cyclotron waves are quite variable. Spatial gradients in the magnetic field may cause this variation as the background field changes between the regions in which

  1. Inelastic heavy ion scattering on 90Zr and 208Pb at intermediate energies

    International Nuclear Information System (INIS)

    Blumenfeld, Y.; Beaumel, D.; Chomaz, P.; Frascaria, N.; Garron, J.P.; Jacmart, J.C.; Roynette, J.C.; Scarpaci, J.A.; Suomijarvi, T.

    1988-01-01

    Heavy ion inelastic scattering has been investigated using the SPEG spectrometer at GANIL. It is shown that the use of such a high resolution spectrometer allows a quantitative study of the giant resonances excited in heavy ion collisions. The contribution of the pick-up break-up mechanism to the high excitation energy region (E > 30 MeV) is then discussed. Recent results obtained with 40 Ar beams at two different incident energies show that target excitations are also present in this energy region

  2. Structure of Ion Outflow in the Martian Magnetotail

    Science.gov (United States)

    McFadden, J. P.; Mitchell, D.; Luhmann, J. G.; Connerney, J. E. P.; Jakosky, B. M.

    2017-12-01

    The Suprathermal And Thermal Ion Composition (STATIC) sensor on the MAVEN spacecraft provides a detailed look at the structure of ion outflow in the Martian magnetotail including ion composition, energization, and flow. Mars' magnetotail contains a mixture of cold (multi-species ions, tailward-moving cold multi-species ions, suprathermal ions of a few tens of eV, warm (about 100 eV) proton populations, and heavy (primarily O+) pickup ions at energies from 1 to 10 keV which may display several simultaneous peaks in energy flux. The cold tailward-moving ions represent a significant fraction of the Martian ion loss, perhaps comparable to loses from molecular oxygen dissociation. The suprathermal tail that accompanies the cold ions varies greatly and provides clues to ion escape. The warm protons, on first examination, appear to be of sheath origin, displaying a similar energy distribution and accompanied by a tenuous warm population at M/Q=2 (which could be either solar wind alphas or molecular hydrogen ions of ionospheric origin). STATIC produces a weak ghost peak at M/Q=11-12 when observing molecular hydrogen ions, but not alphas, often allowing the instrument to distinguish the source of protons. Measurements show the warm protons are of ionospheric origin in the central tail and transition to sheath plasma in the umbra. Energetic (1-10 keV) pickup oxygen in the magnetotail is produced on the nightside, near the pole where the IMF convection electric field points toward the planet, the same hemisphere where sputtering occurs. When two spectral peaks are observed, these tailward-moving ions differ in direction by relatively small angles (about 20 degrees). These peaks can persist for tens of minutes indicating approximately time-stationary acceleration, and therefore acceleration in potential fields. Magnetotail structure and geometry can be inferred not only from the local magnetic field, but also from the measured electron distributions which indicate source

  3. Design developments for the ITER in-Vessel equilibrium pick-up Coils and Halo current Sensors

    International Nuclear Information System (INIS)

    Chitarin, G; Grando, L.; Pomaro, N.; Peruzzo, S.; Taccon, C.

    2006-01-01

    The ITER magnetic diagnostics must provide essential information to be used both for plasma diagnostic purposes, and as feedback signals for the machine control loops. Some of the sensors have to be installed in a hostile environment characterized by severe neutron irradiation and plasma heat loads, which can reduce the sensor lifetime (due to mechanical and electrical damage) and also generate undesired DC signals, which might compromise the accuracy of the measurements obtained by time-integration. The paper is focused on the design development and optimization of a typical in-vessel tangential pick-up Coil. The work is aimed to achieve the required measurement precision in spite of Radiation Induced Electromotive Force (RIEMF) and Radiation Induced Thermo-Electric Sensitivity (RITES), which have recently been documented to take place in Mineral Insulated Cables (MIC). To this purpose, a substantial reduction of the thermal gradient and the maximum temperature due to nuclear heating in the pick-up coils is considered necessary. Within the limits of several heavy engineering constraints, a new concept of magnetic pick up coil has been developed. A winding made of a ceramic-coated conductor (instead of a MIC) and '' impregnated '' with ceramic filler is proposed. Different material choices for the coil support structure have been investigated. Similar issues are related to the Halo Sensor design. The possibility of replacing the circular tubes used as support of the Rogowski coils with a ceramic support in order to avoid the non-linear effect of the magnetic material has also been studied. The replacement of the MIC of the winding with a ceramic-coated wire is also investigated in order to increase of the effective area of the sensor. The paper includes also a critical review of each stage of the measurement chain (probes, cabling, conditioning electronics and data acquisition) in order to assess the compliance with the overall system precision that is required for

  4. Develop and pilot test smart phone/tablet app for paratransit demand-response passenger pick-up alerts to assist passengers with disabilities and reduce no-shows and dwell times.

    Science.gov (United States)

    2016-12-01

    This research produced an arrival notification system for paratransit passengers with disabilities. Almost all existing curb-to-curb paratransit services have significantly large pick-up time window ranging from 20 to 40 minutes from the scheduled ti...

  5. MAVEN SupraThermal and Thermal Ion Compostion (STATIC) Instrument

    Science.gov (United States)

    McFadden, J. P.; Kortmann, O.; Curtis, D.; Dalton, G.; Johnson, G.; Abiad, R.; Sterling, R.; Hatch, K.; Berg, P.; Tiu, C.; Gordon, D.; Heavner, S.; Robinson, M.; Marckwordt, M.; Lin, R.; Jakosky, B.

    2015-12-01

    The MAVEN SupraThermal And Thermal Ion Compostion (STATIC) instrument is designed to measure the ion composition and distribution function of the cold Martian ionosphere, the heated suprathermal tail of this plasma in the upper ionosphere, and the pickup ions accelerated by solar wind electric fields. STATIC operates over an energy range of 0.1 eV up to 30 keV, with a base time resolution of 4 seconds. The instrument consists of a toroidal "top hat" electrostatic analyzer with a 360° × 90° field-of-view, combined with a time-of-flight (TOF) velocity analyzer with 22.5° resolution in the detection plane. The TOF combines a -15 kV acceleration voltage with ultra-thin carbon foils to resolve H+, He^{++}, He+, O+, O2+, and CO2+ ions. Secondary electrons from carbon foils are detected by microchannel plate detectors and binned into a variety of data products with varying energy, mass, angle, and time resolution. To prevent detector saturation when measuring cold ram ions at periapsis (˜10^{1 1} eV/cm2 s sr eV), while maintaining adequate sensitivity to resolve tenuous pickup ions at apoapsis (˜103 eV/cm2 s sr eV), the sensor includes both mechanical and electrostatic attenuators that increase the dynamic range by a factor of 103. This paper describes the instrument hardware, including several innovative improvements over previous TOF sensors, the ground calibrations of the sensor, the data products generated by the experiment, and some early measurements during cruise phase to Mars.

  6. Ion implantation

    International Nuclear Information System (INIS)

    Dearnaley, Geoffrey

    1975-01-01

    First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

  7. Phenotypic correlations between ovum pick-up in vitro production traits and pregnancy rates in Zebu cows.

    Science.gov (United States)

    Vega, W H O; Quirino, C R; Serapião, R V; Oliveira, C S; Pacheco, A

    2015-07-03

    The growth of the Gyr breed in Brazil in terms of genetic gain for milk, along with conditions for market, has led to the use of ovum pick-up in vitro production (OPU-IVP) as a leader in biotechnology for the multiplication of genetic material. The aim of this study was to investigate phenotypic correlations between OPU-IVP-linked characteristics and pregnancy rates registered in an embryo transfer program using Gyr cows as oocyte donors. Data collected from 211 OPU sessions and 298 embryo transfers during the years 2012 and 2013 were analyzed and statistical analysis was performed. Estimates of simple Pearson correlations were calculated for NVcoc and PVcoc (number and proportion of viable cumulus-oocyte complexes, respectively); NcleavD4 and PcleavD4 (number and proportion of cleaved embryos on day 4 of culture, respectively); NTembD7 and PTembD7 (number and proportion of transferable embryos on day 7 of culture, respectively); NPrD30 and PPrD30 (number and proportion of pregnancies 30 days after transfer, respectively); and NPrD60 and PPrD60 (number and proportion of pregnancies 60 days after transfer, respectively). Moderate to moderately high correlations were found for all numerical characteristics, suggesting these as the most suitable parameters for selection of oocyte donors in Gyr programs. NVcoc is proposed as a selection trait due to positive correlations with percentage traits and pregnancy rates 30 and 60 days after transfer.

  8. Location-Routing Problem with Simultaneous Home Delivery and Customer’s Pickup for City Distribution of Online Shopping Purchases

    Directory of Open Access Journals (Sweden)

    Lin Zhou

    2016-08-01

    Full Text Available With the increasing interest in online shopping, the Last Mile delivery is regarded as one of the most expensive and pollutive—and yet the least efficient—stages of the e-commerce supply chain. To address this challenge, a novel location-routing problem with simultaneous home delivery and customer’s pickup is proposed. This problem aims to build a more effective Last Mile distribution system by providing two kinds of service options when delivering packages to customers. To solve this specific problem, a hybrid evolution search algorithm by combining genetic algorithm (GA and local search (LS is presented. In this approach, a diverse population generation algorithm along with a two-phase solution initialization heuristic is first proposed to give high quality initial population. Then, advantaged solution representation, individual evaluation, crossover and mutation operations are designed to enhance the evolution and search efficiency. Computational experiments based on a large family of instances are conducted, and the results obtained indicate the validity of the proposed model and method.

  9. Medium-energy electrons and heavy ions in Jupiter's magnetosphere - Effects of lower hybrid wave-particle interactions

    Science.gov (United States)

    Barbosa, D. D.

    1986-01-01

    A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.

  10. Nucleation and growth of defects in heavy-ion and electron-bombarded metals. Final report for the period ending February 29, 1980

    International Nuclear Information System (INIS)

    Kulcinski, G.L.

    1983-04-01

    He preinjection was found to be essential in nucleating voids in high-purity Al. Interstitial pickup in high-purity V was found to be important even under good vacuum (10 - 6 to 10 - 7 torr). Voids were found to form in V down to 200 0 C. A model was tested against rdiation disordering/ordering in Cu 3 Au. Disordering in CuPd was studied. A small negative heavy ion source (SNICS) was developed for the tandem accelerator

  11. A laser ablation ion source for the FRS ion catcher

    Energy Technology Data Exchange (ETDEWEB)

    Rink, Ann-Kathrin; Ebert, Jens; Petrick, Martin; Reiter, Pascal [Justus Liebig Universitaet Giessen (Germany); Dickel, Timo; Geissel, Hans; Plass, Wolfgang; Scheidenberger, Christoph [Justus Liebig Universitaet Giessen (Germany); GSI, Darmstadt (Germany); Purushothamen, Sivaji [GSI, Darmstadt (Germany)

    2013-07-01

    The FRS Ion Catcher was developed to serve as test bench for the low energy branch of the Super FRS to slow down exotic nuclei and prepare them for further measurements/ experiments. It consists of a cryogenic stopping cell to thermalise the ions, a diagnostic unit for stopping cell characterisation and various radiofrequency quadrupole structures to guide the ions to the Multiple-Reflection Time-of-Flight Mass Spectrometer for mass measurements, α spectroscopy and isobar separation. To characterise the extraction times of the stopping cell, which is one of the main performance parameters of such a cell, a laser ablation ion source has been develped and tested. This ion source provides a sharply defined starting point of the ions for the extraction time measurement. In the future this source will provide reference ions to calibrate the mass spectrometer for accurate mass measurements.

  12. Hot magnetospheric O+ and cold ion behavior in magnetopause reconnection: Cluster observations

    Science.gov (United States)

    Wang, S.; Kistler, L. M.; Mouikis, C. G.; Liu, Y.; Genestreti, K. J.

    2014-12-01

    In reconnection, the presence of heavy ions like O+ increases the ion mass density reducing the fluid's Alfvén speed. In addition, it may modify the reconnection structure, which can also change the reconnection rate. However, because O+ ions have a larger Larmor radii than H+ ions at the same velocity, they may not be fully entrained in the reconnection flow and may have kinetic effects other than just increasing the mass density. In this study, for the first time, the ion velocity distribution functions of H+ and O+ from one magnetopause reconnection event with a strong guide field are analyzed to determine in detail the behavior of the different ion populations. We show that the hot magnetospheric O+ ions, along with the hot magnetospheric H+ ions almost fully participate in the reconnection exhaust flows. Finite Larmor radius effects are also apparent and control how far the ions extend on the magnetosheath side. Ion signatures consistent with heating after being picked up in the reconnection exhaust flow are observed in the H+ and O+ distribution functions. The dynamics of the cold magnetospheric ions depends on where they enter the reconnection region. If they enter the reconnection region at the downstream separatrix, they will be taken away by the magnetic field in an adiabatic way as analyzed by Drake et al. (2009a); if they enter close to the diffusion region, they behave as pick-up ions.

  13. Challenging Narcissus, or Reflecting on Reflecting.

    Science.gov (United States)

    Achilles, C. M.

    The concept of reflective practice and teaching people to be reflective practitioners is examined. The document begins with a look at professional knowledge according to three prominent professionals in the educational administration field: Schon, Schein, and Achilles. "Reflective" strategies that could be incorporated into courses and…

  14. A comb-sampling method for enhanced mass analysis in linear electrostatic ion traps

    Energy Technology Data Exchange (ETDEWEB)

    Greenwood, J. B.; Kelly, O.; Calvert, C. R.; Duffy, M. J.; King, R. B.; Belshaw, L.; Graham, L.; Alexander, J. D.; Williams, I. D. [Centre for Plasma Physics, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Bryan, W. A. [Department of Physics, Swansea University, Swansea SA2 8PP (United Kingdom); Turcu, I. C. E.; Cacho, C. M.; Springate, E. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2011-04-15

    In this paper an algorithm for extracting spectral information from signals containing a series of narrow periodic impulses is presented. Such signals can typically be acquired by pickup detectors from the image-charge of ion bunches oscillating in a linear electrostatic ion trap, where frequency analysis provides a scheme for high-resolution mass spectrometry. To provide an improved technique for such frequency analysis, we introduce the CHIMERA algorithm (Comb-sampling for High-resolution IMpulse-train frequency ExtRAaction). This algorithm utilizes a comb function to generate frequency coefficients, rather than using sinusoids via a Fourier transform, since the comb provides a superior match to the data. This new technique is developed theoretically, applied to synthetic data, and then used to perform high resolution mass spectrometry on real data from an ion trap. If the ions are generated at a localized point in time and space, and the data is simultaneously acquired with multiple pickup rings, the method is shown to be a significant improvement on Fourier analysis. The mass spectra generated typically have an order of magnitude higher resolution compared with that obtained from fundamental Fourier frequencies, and are absent of large contributions from harmonic frequency components.

  15. Methane Group Ions in Saturn’s Outer Magnetosphere?

    Science.gov (United States)

    Sittler, E. C.; Hartle, R. E.; Cooper, J. F.; Johnson, R. E.; Smith, H.; Shappirio, M.; Reisenfeld, D. B.

    2009-12-01

    Yelle et al. [2008] have estimated from Cassini Ion Neutral Mass Spectrometer (INMS) measurements that methane is escaping from Titan’s upper atmosphere at the rate of 2.5-3.0×109 mol/cm2/s and in order to explain this loss rate Strobel [2008] has proposed a hydrodynamic escape model to explain such high loss rates. This translates to loss of 2.8×1027 methane mol/s. The consequence of this work is the formation of a methane torus around Saturn which will dissociate to CH3 and other fragments of methane. The CH3 will then become ionized to form CH3+ with pickup energies ≈ keV after which it can be detected by the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS). Up till now the ion composition within Saturn’s outer magnetosphere in the vicinity of Titan’s orbit have yielded negative results with water group ions W+ dominating. The water group ions probably result from the emission of fast neutrals from the Enceladus torus via charge exchange reactions but still gravitationally bound to Saturn [see Johnson et al., 2005 and Sittler et al. 2006] and then become ionized in the outer magnetosphere as ~≈keV pickup ions. The CAPS IMS produces two ion composition data products, one called Straight Through (ST) and the other Linear Electric Field (LEF). The first has a higher sensitivity, while the latter has a greater discrimination in time-of-flight (TOF). For ST data O+ and CH4+ have similar TOF with the primary discriminator being the O- fragment which appears at a different TOF than for mass 16 ions. One can also look for other discriminators called ghost peaks. In case of LEF W+ ions produce TOF peak close to that for atomic O+ and the methane will produce TOF close to that for atomic C+ which has a significantly different(shorter) TOF than O+. We will be reporting on our continual search for methane ions within Saturn’s outer magnetosphere. References: 1. Yelle, R. V., J. Cui and I.C.F. Müller-Wodarg, JGR, 2008. 2. Strobel, D. F., Icarus

  16. A reflecting time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Tang, X

    1991-01-01

    The design, construction and operation of a reflecting time-of-flight mass spectrometer and the details of the ion mirror are discussed. The principle of velocity focusing with a single-stage ion mirror and the effect of the acceleration region are discussed. The performance of the reflecting instrument is described. Its detection limit is illustrated by observation of [M + H][sup +] ions from [approximately]5-35 femtomoles of various peptides. The factors that affect the resolution are discussed. The principle and operation of the reflecting instrument as a tandem mass spectrometer is described; this involves correlated detection of neutral and ionized fragments. The efficiency, resolution, sensitivity, and mass determination of daughter ions by this method are discussed. Methods of sample preparation are described. By using a nitrocellulose substrate, organic molecular ions as large as bovine insulin (MW 5733) were detected for the first time with low energy (keV) ion bombardment of a solid surface. Many daughter ion spectra resulting from metastable decay of parent ions have been studied. Secondary ions [(CsI)[sub n]Cs][sup +] with n up to [approximately]50 were detected; all clusters were found to be metastable, with most lifetimes <100 [mu]s, and for n>10 the daughter ions are dominant in the mass spectrum. Peptides of mass up to [approximately]2000 u have been studied with the correlated method; the daughter ion spectra were found to be strongly influenced by the identity of the bound cation (H[sup +], Na[sup +], K[sup +], or Ag[sup +]). Many daughter ions formed by known reactions yield structure and sequence information about the peptides. In addition, the [M + Na][sup +] and [M + Ag][sup +] ions decompose by a previously unreported pathway, namely, rearrangement of a C-terminal carboxyl oxygen onto the daughter ion containing the N-terminus. Both the reflected spectra and daughter ion spectra were found useful in peptide sequencing.

  17. Biomolecular ions in superfluid helium nanodroplets

    International Nuclear Information System (INIS)

    Gonzalez Florez, Ana Isabel

    2016-01-01

    droplets has been recorded. The experimental results show well resolved spectra, which are in good agreement with theoretical calculations. Moreover, the weakly interacting nature of helium droplets is confirmed by the excellent agreement obtained with the available gas-phase data. Using standard gas-phase mass spectrometry techniques allows to study the molecular ions as a function of charge state. As a result, the role of the interplay between Coulomb repulsion and hydrogen bonding in the secondary structure of the target molecules can be investigated. For this purpose, the infrared spectra of the proteins ubiquitin and cytochrome c embedded in helium droplets were recorded. The experimental results are interpreted in terms of a charge induced unzipping of the proteins, where a structural transition from helical into extended C 5 -type hydrogen bonded structures occurs. This interpretation is supported by simple energy considerations, as well as by quantum chemical calculations on model peptides. The transition in secondary structure observed here is most likely universal for isolated proteins in the gas phase. Embedding positively charged ions inside helium droplets also offers the possibility to directly investigate the intrinsic properties of helium droplets. One fundamental characteristic of helium droplets is their unique ability to pick up the species with which they collide. In order to gain more insight into this process, the presence of an electrical charge was used to accelerate and detect the ion-doped droplets as a function of the mass and size of the dopant. A systematic investigation of the pick-up probability demonstrates the existence of a dopant dependent minimum droplet size below which no pick-up occurs. As a result, different hypotheses and theoretical models are proposed and discussed in order to shed more light into the constraints and limitations of the pick-up process.

  18. Biomolecular ions in superfluid helium nanodroplets

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Florez, Ana Isabel

    2016-07-01

    droplets has been recorded. The experimental results show well resolved spectra, which are in good agreement with theoretical calculations. Moreover, the weakly interacting nature of helium droplets is confirmed by the excellent agreement obtained with the available gas-phase data. Using standard gas-phase mass spectrometry techniques allows to study the molecular ions as a function of charge state. As a result, the role of the interplay between Coulomb repulsion and hydrogen bonding in the secondary structure of the target molecules can be investigated. For this purpose, the infrared spectra of the proteins ubiquitin and cytochrome c embedded in helium droplets were recorded. The experimental results are interpreted in terms of a charge induced unzipping of the proteins, where a structural transition from helical into extended C{sub 5}-type hydrogen bonded structures occurs. This interpretation is supported by simple energy considerations, as well as by quantum chemical calculations on model peptides. The transition in secondary structure observed here is most likely universal for isolated proteins in the gas phase. Embedding positively charged ions inside helium droplets also offers the possibility to directly investigate the intrinsic properties of helium droplets. One fundamental characteristic of helium droplets is their unique ability to pick up the species with which they collide. In order to gain more insight into this process, the presence of an electrical charge was used to accelerate and detect the ion-doped droplets as a function of the mass and size of the dopant. A systematic investigation of the pick-up probability demonstrates the existence of a dopant dependent minimum droplet size below which no pick-up occurs. As a result, different hypotheses and theoretical models are proposed and discussed in order to shed more light into the constraints and limitations of the pick-up process.

  19. Estradiol and luteinizing hormone concentrations in the follicular aspirate during ovum pickup as predictors of in vitro fertilization (IVF outcome

    Directory of Open Access Journals (Sweden)

    Diaa Sarhan

    2017-03-01

    Full Text Available Background: A relationship between ‘oocyte quality’ and follicular fluid hormones is expected, since its formation coincides with the ‘oocyte maturation’ phase. The aim of this study was to find a possible relation between oocyte quality with follicular luteinizing hormone (LH and estradiol (E2 as hormonal parameters of oocyte quality during ovum pickup for intra-cytoplasmic sperm injection (ICSI. Methods: Concentrations of LH and E2 in individual follicular fluid samples obtained during assisted reproduction treatment were related to oocyte nuclear maturation, fertilization and embryo grading. E2 and LH differences between individual groups of oocytes and embryos were calculated using the paired Student’s t test and ANOVA test. Results: Follicular E2 levels showed a significant positive correlation with oocyte nuclear maturation, fertilization and embryo grading being higher in follicles whose oocytes had matured nucleus (475 ± 142.9 ng/ml vs. 332 ± 76.4 ng/ml, P value <0.001, normally fertilized (502.5 ± 131.3 ng/ml vs. 339.8 ± 78.3 ng/ml, P value <0.001 and developed into good quality embryos (596.9 ± 72.4 ng/ml grade A vs. 511.7 ± 73 ng/ml grade B vs. 310.9 ± 57 ng/ml grade C, P value <0.001. However Follicular LH was only positively correlated with oocyte nuclear maturation. Conclusions: The local follicular environment may play a key role in the observed differences in oocyte quality. Our results suggest that the use follicular E2 may be of value in the assessment of oocyte quality. If there is a marker for oocyte quality, it would be possible to select oocytes rather than embryos, which may improve selection criteria of the best embryo to transfer, therefore increases success rate of ICSI.

  20. Diffuse ions produced by electromagnetic ion beam instabilities

    International Nuclear Information System (INIS)

    Winske, D.; Leroy, M.M.

    1984-01-01

    The evolution of the electromagnetic ions beam instability driven by the reflected ion component backstreaming away from the earth's how shock into the foreshock region is studied by means computer simulation. The linear the quasi-linear states of the instability are found to be in good agreement with known results for the resonant model propagating parallel to the beam along the magnetic field and with theory developed in this paper for the nonresonant mode, which propagates antiparallel to the beam direction. The quasi-linear stage, which produces large amplitude 8Bapprox.B, sinusoidal transverse waves and ''intermediate'' ion distribution, is terminated by a nonlinear phase in which strongly nonlinear, compressive waves and ''diffuse'' ion distributions are produced. Additional processes by which the diffuse ions are accelerated to observed high energies are not addressed. The results are discussed in terms of the ion distributions and hydromagnetic waves observed in the foreshock of the earth's bow shock and of interplanetary shocks

  1. Charge exchange studies with Gold ions at the Brookhaven Booster and AGS

    International Nuclear Information System (INIS)

    Ahrens, L.A.; Hseuh, H.C.; Roser, T.

    1994-01-01

    Efficient acceleration of Gold ions to ll GeV/nucleon places strong constraints on the vacuum and also on the choice of thickness and material of the necessary stripping foils. Results of a number of detailed experimental studies performed with the Gold beam at the Brookhaven Booster and AGS to determine the relevant electron stripping and pick-up probabilities are presented. Of particular interest is the lifetime of the relatively low energy, partially stripped Gold beam in the Booster and the stripping efficiency to Helium-like AU +77 for injection into the AGS

  2. Energetic particles beyond the heliospheric shock: Anomalous Cosmic Rays (ACRs), Pick-Up Ions (PUIs) and the associated energetic neutral atoms (ENAs)

    International Nuclear Information System (INIS)

    Fichtner, Horst; Czechowski, Andrzej; Fahr, Hans J.; Lay, Guenter

    2000-01-01

    The Voyager 1 spacecraft is expected to encounter the heliospheric termination shock within the next decade. Besides the ongoing discussion how to possibly predict the time of this encounter, there is a growing interest into a more detailed description of the region beyond the heliospheric shock, i.e., the heliosheath. Refinements of the so far rather crude models will facilitate interpretation of forthcoming data. We report on results obtained with our model of the transport of ACRs in the heliosheath. In improvement of earlier approaches it is based on a solar wind background flow computed with a self-consistent large-scale model of the heliosphere. Besides these downstream ACR spectra, which will become accessible for in situ observation as soon as the Voyager spacecraft will have crossed the heliospheric shock, we study the potential of observations of the flux of ENAs to remotely explore the structure of the heliosheath. In particular, as part of a comparison of the various ENA sources, we will address the significance of the contribution of those ENAs resulting from a de-charging of PUIs

  3. Ion Colliders

    CERN Document Server

    Fischer, W

    2014-01-01

    High-energy ion colliders are large research tools in nuclear physics to study the Quark-Gluon-Plasma (QGP). The range of collision energy and high luminosity are important design and operational considerations. The experiments also expect flexibility with frequent changes in the collision energy, detector fields, and ion species. Ion species range from protons, including polarized protons in RHIC, to heavy nuclei like gold, lead and uranium. Asymmetric collision combinations (e.g. protons against heavy ions) are also essential. For the creation, acceleration, and storage of bright intense ion beams, limits are set by space charge, charge change, and intrabeam scattering effects, as well as beam losses due to a variety of other phenomena. Currently, there are two operating ion colliders, the Relativistic Heavy Ion Collider (RHIC) at BNL, and the Large Hadron Collider (LHC) at CERN.

  4. Recoil ions

    International Nuclear Information System (INIS)

    Cocke, C.L.; Olson, R.E.

    1991-01-01

    The collision of a fast moving heavy ion with a neutral atomic target can produce very highly charged but slowly moving target ions. This article reviews experimental and theoretical work on the production and use of recoil ions beyond the second ionization state by beams with specific energies above 0.5 MeV/amu. A brief historical survey is followed by a discussion of theoretical approaches to the problem of the removal of many electrons from a neutral target by a rapid, multiply charged projectile. A discussion of experimental techniques and results for total and differential cross sections for multiple ionization of atomic and molecular targets is given. Measurements of recoil energy are discussed. The uses of recoil ions for in situ spectroscopy of multiply charged ions, for external beams of slow, highly charged ions and in ion traps are reviewed. Some possible future opportunities are discussed. (orig.)

  5. A spin-filter polarimeter for low energy hydrogen and deuterium ion beams

    International Nuclear Information System (INIS)

    Lemieux, S.K.; Clegg, T.B.; Karwowski, H.J.; Thompson, W.J.; Crosson, E.R.

    1993-01-01

    An efficient polarimeter which reveals populations of individual hyperfine states of nuclear-spin-polarized H ± (or D ± ) ion beams has been tested. This device is based on unique properties of a three-level interaction in the 2S 1/2 and 2P 1/2 states of hydrogen (or deuterium) atoms, created when the incident, polarized ion beams undergo electron pickup in cesium vapour. Used on a polarized ion source, its efficiency faciy facilitates both rapid optimization and continual monitoring of parameters that affect the beam polarization. With such sources, and perhaps in applications with polarized gas jet targets, the device has potential for an absolute accuracy of better than 2%. (orig.)

  6. Temperature-reflection I

    DEFF Research Database (Denmark)

    McGady, David A.

    2017-01-01

    -temperature path integrals for quantum field theories (QFTs) should be T-reflection invariant. Because multi-particle partition functions are equal to Euclidean path integrals for QFTs, we expect them to be T-reflection invariant. Single-particle partition functions though are often not invariant under T......In this paper, we revisit the claim that many partition functions are invariant under reflecting temperatures to negative values (T-reflection). The goal of this paper is to demarcate which partition functions should be invariant under T-reflection, and why. Our main claim is that finite...... that T-reflection is unrelated to time-reversal. Finally, we study the interplay between T-reflection and perturbation theory in the anharmonic harmonic oscillator in quantum mechanics and in Yang-Mills in four-dimensions. This is the first in a series of papers on temperature-reflections....

  7. Ion colliders

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions (77Asb1, 81Bou1). The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  8. Ion colliders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.

    2011-12-01

    Ion colliders are research tools for high-energy nuclear physics, and are used to test the theory of Quantum Chromo Dynamics (QCD). The collisions of fully stripped high-energy ions create matter of a temperature and density that existed only microseconds after the Big Bang. Ion colliders can reach higher densities and temperatures than fixed target experiments although at a much lower luminosity. The first ion collider was the CERN Intersecting Storage Ring (ISR), which collided light ions [77Asb1, 81Bou1]. The BNL Relativistic Heavy Ion Collider (RHIC) is in operation since 2000 and has collided a number of species at numerous energies. The CERN Large Hadron Collider (LHC) started the heavy ion program in 2010. Table 1 shows all previous and the currently planned running modes for ISR, RHIC, and LHC. All three machines also collide protons, which are spin-polarized in RHIC. Ion colliders differ from proton or antiproton colliders in a number of ways: the preparation of the ions in the source and the pre-injector chain is limited by other effects than for protons; frequent changes in the collision energy and particle species, including asymmetric species, are typical; and the interaction of ions with each other and accelerator components is different from protons, which has implications for collision products, collimation, the beam dump, and intercepting instrumentation devices such a profile monitors. In the preparation for the collider use the charge state Z of the ions is successively increased to minimize the effects of space charge, intrabeam scattering (IBS), charge change effects (electron capture and stripping), and ion-impact desorption after beam loss. Low charge states reduce space charge, intrabeam scattering, and electron capture effects. High charge states reduce electron stripping, and make bending and acceleration more effective. Electron stripping at higher energies is generally more efficient. Table 2 shows the charge states and energies in the

  9. Liberating Moral Reflection

    Science.gov (United States)

    Horell, Harold D.

    2013-01-01

    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  10. Some calculated (p,α) cross-sections using the alpha particle knock-on and triton pick-up reaction mechanisms: An optimisation of the single-step Feshbach-Kerman-Koonin (FKK) theory

    Energy Technology Data Exchange (ETDEWEB)

    Olise, Felix S.; Ajala, Afis; Olamiyl, Hezekiah B. [Dept. of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife (Nigeria)

    2016-04-15

    The Feshbach-Kerman-Koonin (FKK) multi-step direct (MSD) theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,α) reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core) by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process) and proton-triton (for the pick-up process) interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

  11. Some Calculated (p,α Cross-Sections Using the Alpha Particle Knock-On and Triton Pick-Up Reaction Mechanisms: An Optimisation of the Single-Step Feshbach–Kerman–Koonin (FKK Theory

    Directory of Open Access Journals (Sweden)

    Felix S. Olise

    2016-04-01

    Full Text Available The Feshbach–Kerman–Koonin (FKK multi-step direct (MSD theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,α reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process and proton-triton (for the pick-up process interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

  12. Time-resolved Shielded-Pickup Measurements and Modeling of Beam Conditioning Effects on Electron Cloud Buildup at CesrTA

    CERN Document Server

    Crittenden, J A; Liu, X; Palmer, M A; Santos, S; Sikora, J P; Kato, S; Calatroni, S; Rumolo, G

    2012-01-01

    The Cornell Electron Storage Ring Test Accelerator program includes investigations into electron cloud buildup in vacuum chambers with various coatings. Two 1.1-mlong sections located symmetrically in the east and west arc regions are equipped with BPM-like pickup detectors shielded against the direct beam-induced signal. They detect cloud electrons migrating through an 18-mm-diameter pattern of 0.76 mm-diameter holes in the top of the chamber. A digitizing oscilloscope is used to record the signals, providing time-resolved information on cloud development. We present new measurements of the effect of beam conditioning on a newly-installed amorphous carbon coated chamber, as well as on an extensively conditioned chamber with a diamond-like carbon coating. The ECLOUD modeling code is used to quantify the sensitivity of these measurements to model parameters, differentiating between photoelectron and secondary-electron production processes.

  13. Possible origin and roles of nano-porosity in ZrO2 scales for hydrogen pick-up in Zr alloys

    Science.gov (United States)

    Lindgren, Mikaela; Geers, Christine; Panas, Itai

    2017-08-01

    A mechanistic understanding of Wagnerian build-up and subsequent non-Wagnerian break-down of barrier oxide upon oxidation of zirconium alloys by water is reiterated. Hydrogen assisted build-up of nano-porosity is addressed. Growth of sub-nanometer wide stalactitic pores owing to increasing aggregation of neutral oxygen vacancies offering a means to permeate hydrogen into the alloy is explored by density functional theory. The Wagnerian channel utilizes charge separation allowing charged oxygen vacancies and electrons to move separately from nominal anode to nominal cathode. This process becomes increasingly controlled by the charging of the barrier oxide resulting in sub-parabolic rate law for oxide growth. The break-down of the barrier oxide is understood to be preceded by avalanching hydrogen pick-up in the alloy. Pore mediated diffusion allows water to effectively short circuit the barrier oxide.

  14. Historical aspects of heavy ion radiotherapy

    International Nuclear Information System (INIS)

    Raju, M.R.

    1995-01-01

    This paper presents historical developments of heavy-ion radiotherapy including discussion of HILAC and HIMAC and discussion of cooperation between Japan and the United States, along with personal reflections

  15. ion irradiation

    Indian Academy of Sciences (India)

    Swift heavy ions interact predominantly through inelastic scattering while traversing any polymer medium and produce excited/ionized atoms. Here samples of the polycarbonate Makrofol of approximate thickness 20 m, spin coated on GaAs substrate were irradiated with 50 MeV Li ion (+3 charge state). Build-in ...

  16. Ion microprobes

    International Nuclear Information System (INIS)

    Coles, J.N.; Long, J.V.P.

    1977-01-01

    An ion microprobe is described that has an ion extraction arrangement comprising two separate paths for ions and electrons diverging from a common point. A cone shaped or pyramidal guard electrode surrounds each path the apex angles being equal and coinciding with the said point. The guard electrodes are positioned to lie tangentially to each other and to a planar surface including the said point. An aperture is provided for the two paths at the apexes of both guard electrodes, and electrical connections between the guard electrodes enable the same potential to be applied to both guard electrodes. Means are provided for generating oppositely polarised electric fields within the guard electrodes, together with means for causing a focused ion beam to strike the common point without suffering astigmatism. The means for causing a focused ion beam to strike the said point includes an ion gun for directing an ion beam along one of the paths and means to provide an axial accelerating field there along. Optical viewing means are also provided. Existing designs enable only ions or electrons, but not both, to be extracted at any one time. (U.K.)

  17. Beam position monitor R&D for keV ion beams

    CERN Document Server

    Naveed, S; Nosych, A; Søby,L

    2013-01-01

    Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring (BPM) system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams with a focus on the ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably.

  18. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... without reducing reflection to an effect of the social structures and cultural norms in which it is embedded. Based on the developed theoretical framework, this article analyses how a renaissance ‘mirror for princes’ and contemporary research-based management education mediate reflection. The content...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  19. Apparatus for neutralization of accelerated ions

    International Nuclear Information System (INIS)

    Fink, J.H.; Frank, A.M.

    1979-01-01

    Apparatus is described for neutralization of a beam of accelerated ions, such as hydrogen negative ions (H - ), using relatively efficient strip diode lasers which emit monochromatically at an appropriate wavelength (lambda = 8000 A for H - ions) to strip the excess electrons by photodetachment. A cavity, formed by two or more reflectors spaced apart, causes the laser beams to undergo multiple reflections within the cavity, thus increasing the efficiency and reducing the illumination required to obtain an acceptable percentage (approx. 85%) of neutralization

  20. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  1. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water-reflected (i.e. surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established

  2. Ion implantation

    International Nuclear Information System (INIS)

    Johnson, E.

    1986-01-01

    It is the purpose of the present paper to give a review of surface alloy processing by ion implantation. However, rather than covering this vast subject as a whole, the survey is confined to a presentation of the microstructures that can be found in metal surfaces after ion implantation. The presentation is limited to alloys processed by ion implantation proper, that is to processes in which the alloy compositions are altered significantly by direct injection of the implanted ions. The review is introduced by a presentation of the processes taking place during development of the fundamental event in ion implantation - the collision cascade, followed by a summary of the various microstructures which can be formed after ion implantation into metals. This is compared with the variability of microstructures that can be achieved by rapid solidification processing. The microstructures are subsequently discussed in the light of the processes which, as the implantations proceed, take place during and immediately after formation of the individual collision cascades. These collision cascades define the volumes inside which individual ions are slowed down in the implanted targets. They are not only centres for vigorous agitation but also the sources for formation of excess concentrations of point defects, which will influence development of particular microstructures. A final section presents a selection of specific structures which have been observed in different alloy systems. (orig./GSCH)

  3. High-resolution ion pulse ionization chamber with air filling for the {sup 222}Rn decays detection

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilyuk, Yu.M.; Gangapshev, A.M.; Gezhaev, A.M.; Etezov, R.A.; Kazalov, V.V.; Kuzminov, V.V. [Baksan Neutrino Observatory,Institute for Nuclear Research RAS, 361609 Neutrino (Russian Federation); Panasenko, S.I. [V.N.Karazin Kharkiv National University, 61022 Kharkiv (Ukraine); Ratkevich, S.S., E-mail: ssratk@gmail.com [V.N.Karazin Kharkiv National University, 61022 Kharkiv (Ukraine); Tekueva, D.A.; Yakimenko, S.P. [Baksan Neutrino Observatory,Institute for Nuclear Research RAS, 361609 Neutrino (Russian Federation)

    2015-11-21

    The construction and characteristics of the cylindrical ion pulse ionization chamber (CIPIC) with a working volume of 3.2 L are described. The chamber is intended to register α-particles from the {sup 222}Rn and its daughter's decays in the filled air sample. The detector is less sensitive to electromagnetic pick-ups and mechanical noises. The digital pulse processing method is proposed to improve the energy resolution of the ion pulse ionization chamber. An energy resolution of 1.6% has been achieved for the 5.49 MeV α-line. The dependence of the energy resolution on high voltage and working media pressure has been investigated and the results are presented. - Highlights: • The construction and characteristics of the cylindrical ion pulse ionization chamber (CIPIC) with a working volume of 3.2 L are described. • The chamber is intended to register alpha-particles from {sup 222}Rn and its daughter's decays in the filled air sample. • The detector is less sensitive to electromagnetic pick-ups and mechanical noises. • An energy resolution of 1.6% has been achieved for the 5.49 MeV alpha-line. The dependence of the energy resolution on high voltage and working media pressure have been investigated and the results are presented.

  4. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina

    2011-01-01

    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...

  5. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2016-01-01

    will take a look at the establishing of the modern self and possibilities of self-reflection, too. My examples will be from the so-called dark-selfies and from a new selfie form, which merge the present with the previous progressing into the future. I will discuss the media reflections as loos and/or gain...

  6. Reflection: A Socratic approach.

    Science.gov (United States)

    Van Seggelen-Damen, Inge C M; Van Hezewijk, René; Helsdingen, Anne S; Wopereis, Iwan G J H

    2017-12-01

    Reflection is a fuzzy concept. In this article we reveal the paradoxes involved in studying the nature of reflection. Whereas some scholars emphasize its discursive nature, we go further and underline its resemblance to the self-biased dialogue Socrates had with the slave in Plato's Meno . The individual and internal nature of the reflection process creates difficulty for studying it validly and reliably. We focus on methodological issues and use Hans Linschoten's view of coupled systems to identify, analyze, and interpret empirical research on reflection. We argue that researchers and research participants can take on roles in several possible system couplings. Depending on who controls the manipulation of the stimulus, who controls the measuring instrument, who interprets the measurement and the response, different types of research questions can be answered. We conclude that reflection may be validly studied by combining different couplings of experimenter, manipulation, stimulus, participant, measurement, and response.

  7. Longitudinal schottky spectra of a bunched Ne10+ ion beam at the CSRe

    International Nuclear Information System (INIS)

    Wen Weiqiang; Ma Xinwen; Zhang Dacheng

    2013-01-01

    The longitudinal Schottky spectra of a radio-frequency (RF) bunched and electron cooled 22Ne 10+ ion beam at 70 MeV/u have been studied by a newly installed resonant Schottky pick-up at the experimental cooler storage ring (CSRe), at IMP. For an RF-bunched ion beam, a longitudinal momentum spread of Δp/p=1.6 × 10 -5 has been reached with less than 107 stored ions. The reduction of momentum spread compared with a coasting ion beam was observed from Schottky noise signal of the bunched ion beam. In order to prepare the future laser cooling experiment at the CSRe, the RF-bunching power was modulated at 25 th , 50 th and 75 th harmonic of the revolution frequency, effective bunching amplitudes were extracted from the Schottky spectrum analysis. Applications of Schottky noise for measuring beam lifetime with ultra-low intensity of ion beams are presented, and it is relevant to upcoming experiments on laser cooling of relativistic heavy ion beams and nuclear physics at the CSRe. (authors)

  8. Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

    International Nuclear Information System (INIS)

    Charles Doret, S; Amini, Jason M; Wright, Kenneth; Volin, Curtis; Killian, Tyler; Ozakin, Arkadas; Denison, Douglas; Hayden, Harley; Pai, C-S; Slusher, Richart E; Harter, Alexa W

    2012-01-01

    Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled dc electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on dc electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains. (paper)

  9. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

  10. Computer simulation of the topography evolution on ion bombarded surfaces

    CERN Document Server

    Zier, M

    2003-01-01

    The development of roughness on ion bombarded surfaces (facets, ripples) on single crystalline and amorphous homogeneous solids plays an important role for example in depth profiling techniques. To verify a faceting mechanism based not only on sputtering by directly impinging ions but also on the contribution of reflected ions and the redeposition of sputtered material a computer simulation has been carried out. The surface in this model is treated as a two-dimensional line segment profile. The model describes the topography evolution on ion bombarded surfaces including the growth mechanism of a facetted surface, using only the interplay of reflected and primary ions and redeposited atoms.

  11. The Reflective Foundation

    DEFF Research Database (Denmark)

    Lunde Jørgensen, Ida

    Private foundations and cultural philanthropy by élites is viewed with increasing skepticism in recent years, begging the question of the extent to which foundations reflect on their role vis a vis wider societal norms. Through the prism of the New Carlsberg Foundation, financed by the brewery...... Carlsberg A/S, the paper seeks to elucidate the way in which one culturally significant foundation from Denmark has reflected on - and legitimated - its work and investments at critical moments in the past decades. The paper indicates a foundation with a high degree of reflection on the wider societal...

  12. Clinic Attendance for Antiretroviral Pills Pick-Up among HIV-Positive People in Nepal: Roles of Perceived Family Support and Associated Factors

    Science.gov (United States)

    Kikuchi, Kimiyo; Ghimire, Mamata; Shibanuma, Akira; Pant, Madhab Raj; Poudel, Krishna C.; Jimba, Masamine

    2016-01-01

    Introduction HIV-positive people’s clinic attendance for medication pick-up is critical for successful HIV treatment. However, limited evidence exists on it especially in low-income settings such as Nepal. Moreover, the role of family support in clinic attendance remains under-explored. Therefore, this study was conducted to examine the association between perceived family support and regular clinic attendance and to assess factors associated with regular clinic attendance for antiretroviral pills pick-up among HIV-positive individuals in Nepal. Methods A cross-sectional study was conducted among 423 HIV-positive people in three districts of Nepal. Clinic attendance was assessed retrospectively for the period of 12 months. To assess the factors associated, an interview survey was conducted using a semi-structured questionnaire from July to August, 2015. Multiple logistic regression models were used to assess the factors associated with regular clinic attendance. Results Of 423 HIV-positive people, only 32.6% attended the clinics regularly. They were more likely to attend them regularly when they received high family support (AOR = 3.98, 95% CI = 2.29, 6.92), participated in support programs (AOR = 1.68, 95% CI = 1.00, 2.82), and had knowledge on the benefits of antiretroviral therapy (AOR = 2.62, 95% CI = 1.15, 5.99). In contrast, they were less likely to attend them regularly when they commuted more than 60 minutes to the clinics (AOR = 0.53, 95% CI = 0.30, 0.93), when they self-rated their health status as being very good (AOR = 0.13, 95% CI = 0.04, 0.44), good (AOR = 0.14, 95% CI = 0.04, 0.46), and fair (AOR = 0.21, 95% CI = 0.06, 0.70). Conclusion HIV-positive individuals are more likely to attend the clinics regularly when they receive high family support, know the benefits of antiretroviral therapy, and participate in support programs. To improve clinic attendance, family support should be incorporated with HIV care programs in resource limited settings

  13. Clinic Attendance for Antiretroviral Pills Pick-Up among HIV-Positive People in Nepal: Roles of Perceived Family Support and Associated Factors.

    Science.gov (United States)

    Ayer, Rakesh; Kikuchi, Kimiyo; Ghimire, Mamata; Shibanuma, Akira; Pant, Madhab Raj; Poudel, Krishna C; Jimba, Masamine

    2016-01-01

    HIV-positive people's clinic attendance for medication pick-up is critical for successful HIV treatment. However, limited evidence exists on it especially in low-income settings such as Nepal. Moreover, the role of family support in clinic attendance remains under-explored. Therefore, this study was conducted to examine the association between perceived family support and regular clinic attendance and to assess factors associated with regular clinic attendance for antiretroviral pills pick-up among HIV-positive individuals in Nepal. A cross-sectional study was conducted among 423 HIV-positive people in three districts of Nepal. Clinic attendance was assessed retrospectively for the period of 12 months. To assess the factors associated, an interview survey was conducted using a semi-structured questionnaire from July to August, 2015. Multiple logistic regression models were used to assess the factors associated with regular clinic attendance. Of 423 HIV-positive people, only 32.6% attended the clinics regularly. They were more likely to attend them regularly when they received high family support (AOR = 3.98, 95% CI = 2.29, 6.92), participated in support programs (AOR = 1.68, 95% CI = 1.00, 2.82), and had knowledge on the benefits of antiretroviral therapy (AOR = 2.62, 95% CI = 1.15, 5.99). In contrast, they were less likely to attend them regularly when they commuted more than 60 minutes to the clinics (AOR = 0.53, 95% CI = 0.30, 0.93), when they self-rated their health status as being very good (AOR = 0.13, 95% CI = 0.04, 0.44), good (AOR = 0.14, 95% CI = 0.04, 0.46), and fair (AOR = 0.21, 95% CI = 0.06, 0.70). HIV-positive individuals are more likely to attend the clinics regularly when they receive high family support, know the benefits of antiretroviral therapy, and participate in support programs. To improve clinic attendance, family support should be incorporated with HIV care programs in resource limited settings. Service providers should also consider

  14. Effect of frequency of clinic visits and medication pick-up on antiretroviral treatment outcomes: a systematic literature review and meta-analysis.

    Science.gov (United States)

    Mutasa-Apollo, Tsitsi; Ford, Nathan; Wiens, Matthew; Socias, Maria Eugenia; Negussie, Eyerusalem; Wu, Ping; Popoff, Evan; Park, Jay; Mills, Edward J; Kanters, Steve

    2017-07-21

    Expanding and sustaining antiretroviral therapy (ART) coverage may require simplified HIV service delivery strategies that concomitantly reduce the burden of care on the health system and patients while ensuring optimal outcomes. We conducted a systematic review to assess the impact of reduced frequency of clinic visits and drug dispensing on patient outcomes. As part of the development process of the World Health Organization antiretroviral (ARV) guidelines, we systematically searched medical literature databases for publications up to 30 August 2016. Information was extracted on trial characteristics, patient characteristics and the following outcomes: mortality, morbidity, treatment adherence, retention, patient and provider acceptability, cost and patients exiting the programme. When feasible, conventional pairwise meta-analyses were conducted. Results and discussion Of 6443 identified citations, 21 papers, pertaining to 16 studies, were included in this review, with 11 studies contributing to analyses. Although analyses were feasible, they were limited by the sparse evidence base, despite the importance of the research area, and relatively low quality. Comparative analyses of eight studies reporting on frequency of clinic visits showed that less frequent clinic visits led to higher odds of being retained in care (odds ratio [OR]: 1.90; 95% CI: 1.21-2.99). No differences were found with respect to viral failure, morbidity or mortality; however, most estimates were favourable to reduced clinic visits. Reduced frequency of ARVs pick-ups showed a trend towards better retention (OR: 1.93; 95% CI: 0.62-6.04). Strategies using community support tended to have better outcomes; however, their implementation varied, particularly by location. External validity may be questionable. Our systematic review suggests that reduction of clinical visits (and likely ARVs pick-ups) may improve clinical outcomes, and that they are a viable option to relieve health systems and reduce

  15. Experimental study of regenerative desiccant integrated solar dryer with and without reflective mirror

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, V. [Department of Mechanical Engineering, Sathyabama University, Chennai, 600 119 (India); Natarajan, E. [Institute for Energy Studies, College of Engineering, Anna University, Chennai, 600 025 (India)

    2007-06-15

    An indirect forced convection with desiccant integrated solar dryer has been built and tested. The main parts are: a flat plate solar air collector, a drying chamber, desiccant bed and a centrifugal blower. The system is operated in two modes, sunshine hours and off sunshine hours. During sun shine hours the hot air from the flat plate collector is forced to the drying chamber for drying the product and simultaneously the desiccant bed receives solar radiation directly and through the reflected mirror. In the off sunshine hours, the dryer is operated by circulating the air inside the drying chamber through the desiccant bed by a reversible fan. The dryer is used to dry 20 kg of green peas and pineapple slices. Drying experiments were conducted with and without the integration of desiccant unit. The effect of reflective mirror on the drying potential of desiccant unit was also investigated. With the inclusion of reflective mirror, the drying potential of the desiccant material is increased by 20% and the drying time is reduced. The drying efficiency of the system varies between 43% and 55% and the pick-up efficiency varies between 20% and 60%, respectively. Approximately in all the drying experiments 60% of moisture is removed by air heated using solar energy and the remainder by the desiccant. The inclusion of reflective mirror on the desiccant bed makes faster regeneration of the desiccant material. (author)

  16. Seasonal soybean crop reflectance

    Science.gov (United States)

    Lemaster, E. W. (Principal Investigator); Chance, J. E.

    1983-01-01

    Data are presented from field measurements of 1980 including 5 acquisitions of handheld radiometer reflectance measurements, 7 complete sets of parameters for implementing the Suits mode, and other biophysical parameters to characterize the soybean canopy. LANDSAT calculations on the simulated Brazilian soybean reflectance are included along with data collected during the summer and fall on 1981 on soybean single leaf optical parameters for three irrigation treatments. Tests of the Suits vegetative canopy reflectance model for the full hemisphere of observer directions as well as the nadir direction show moderate agreement for the visible channels of the MSS and poor agreement in the near infrared channel. Temporal changes in the spectral characteristics of the single leaves were seen to occur as a function of maturity which demonstrates that the absorptance of a soybean single leaf is more a function of thetransmittancee characteristics than the seasonally consistent single leaf reflectance.

  17. Wave reflections from breakwaters

    OpenAIRE

    Dickson, William S.

    1994-01-01

    A new method is presented for estimating the reflection of a random, multi-directional sea from a coastal structure. The technique is applicable to an array of wave gauges of arbitrary geometry deployed seaward of the reflector. An expansion for small oblique wave incidence angles is used to derive an approximate relationship between measured array cross-spectra and a small number of parameters that describe the incident wave properties and the reflectivity of the structure. Model tests with ...

  18. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  19. Thoughts on Reflection (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2010-06-01

    Full Text Available There has been some acknowledgement in the published literature that reflection is a crucial element of the evidence based library and information practice (EBLIP model we have adopted (Booth 2004, 2006; Grant 2007; Helliwell 2007. As we work through a problem and try to incorporate the best available evidence into our decision making, reflection is required at several stages, including the very identification of the problem through to our assessment of the process itself and what we have learned in order to inform future practice. However, reflection and reflective writing have not fully been integrated into the process we espouse, and very little has been done to look more closely at this element of the model and how it can be integrated into professional learning.In a recently published research article, Sen (2010 confirms the relationship between reflection and several aspects of professional practice. These include critical review and decision making, two aspects that are tied closely to the evidence based process. Sen notes: Students were more likely to show evidence of learning, self‐development, the ability to review issues crucially, awareness of their own mental functions, ability to make decision [sic] and being empowered when they had mastered the art of reflective practice and the more deeply analytical reflective writing. (p.84 EBLIP (the journal tries to incorporate elements of reflection within the articles we publish. While we clearly believe in the need for our profession to do quality research and publish that research so that it can be accessible to practitioners, we also know that research cannot be looked at in isolation. Our evidence summaries are one way of reflecting critically on previously published research, and in the same vein, our classics bring older research studies back to the foreground. This work needs to continue to be discussed and looked at for its impact on our profession.More directly, the Using

  20. Heteroditopic receptors for ion-pair recognition.

    Science.gov (United States)

    McConnell, Anna J; Beer, Paul D

    2012-05-21

    Ion-pair recognition is a new field of research emerging from cation and anion coordination chemistry. Specific types of heteroditopic receptor designs for ion pairs and the complexity of ion-pair binding are discussed to illustrate key concepts such as cooperativity. The importance of this area of research is reflected by the wide variety of potential applications of ion-pair receptors, including applications as membrane transport and salt solubilization agents and sensors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Conditioning of BPM pickup signals for operations of the Duke storage ring with a wide range of single-bunch current

    Science.gov (United States)

    Xu, Wei; Li, Jing-Yi; Huang, Sen-Lin; Z. Wu, W.; Hao, H.; P., Wang; K. Wu, Y.

    2014-10-01

    The Duke storage ring is a dedicated driver for the storage ring based oscillator free-electron lasers (FELs), and the High Intensity Gamma-ray Source (HIGS). It is operated with a beam current ranging from about 1 mA to 100 mA per bunch for various operations and accelerator physics studies. High performance operations of the FEL and γ-ray source require a stable electron beam orbit, which has been realized by the global orbit feedback system. As a critical part of the orbit feedback system, the electron beam position monitors (BPMs) are required to be able to precisely measure the electron beam orbit in a wide range of the single-bunch current. However, the high peak voltage of the BPM pickups associated with high single-bunch current degrades the performance of the BPM electronics, and can potentially damage the BPM electronics. A signal conditioning method using low pass filters is developed to reduce the peak voltage to protect the BPM electronics, and to make the BPMs capable of working with a wide range of single-bunch current. Simulations and electron beam based tests are performed. The results show that the Duke storage ring BPM system is capable of providing precise orbit measurements to ensure highly stable FEL and HIGS operations.

  2. Creation, Identity and Reflection

    Directory of Open Access Journals (Sweden)

    Alina Beatrice Cheşcă

    2015-05-01

    Full Text Available The paper “Creation, Identity and Reflection” approaches the identification in the “mirror” of reality with creation, in other words seeking the authors’ identity in the reflected images. Reflection means attempting to find oneself, the mirror being the main principle of creation. Many characters become interesting only when they step into the world beyond the mirror, when their faces are doubled by the other self or when their selves are returned by other characters. The narcissistic concept of the mirror, i.e. the reflection in the mirror and the representation of the mirror itself, is a recurrent one in literature, but the reflection of the self which is not the self (as it is a reflection does not necessarily appear in a mirror or in a photograph or portrait. Sometimes, the not-self is returned to the self by another person or character. As far as Oscar Wilde’s theories are concerned, the main idea is that people are interesting for their masks, not for their inner nature. What Wilde calls “inner nature” is the characters’ un-reflected self and the mask is the reflection, the self in the mirror. Some characters’ relationships develop within a fiction that they dramatically try to preserve and protect with the risk of suffering. They refuse to take off the masks which define them in the others’ minds and hearts; the narcissistic individuals (both artists and characters seek and love their own image which they project upon facts, thus creating a fictive realm.

  3. A Substantial Plume of Escaping Planetary Ions in the MSE Northern Hemisphere Observed by MAVEN

    Science.gov (United States)

    Dong, Y.; Fang, X.; Brain, D. A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.; Curry, S.; Harada, Y.; Luhmann, J. G.; Jakosky, B. M.

    2015-12-01

    The Mars-solar wind interaction accelerates and transports planetary ions away from Mars through a number of processes, including pick-up by the electromagnetic fields. The Mars Atmospheric and Volatile EvolutioN (MAVEN) spacecraft has frequently detected strong escaping planetary ion fluxes in both tailward and upstream solar wind motional electric field directions since the beginning of its science phase in November 2014. Our statistical study using three-month MAVEN data from November 2014 through February 2015 illustrates a substantial plume-like escaping planetary ion population organized by the upstream electric field with strong fluxes widely distributed in the northern hemisphere of the Mars-Sun-Electric-field (MSE) coordinate system, which is generally consistent with model predictions. The plume constitutes an important planetary ion escape channel from the Martian atmosphere in addition to the tailward escape. The >25eV O+ escape rate through the plume is estimated to be ~35% of the tailward escape and ~25% of the total escape. We will compare the dynamics of the plume and tailward escaping ions based on their velocity-space distributions with respect to the electromagnetic fields. We will also discuss the variations of the plume characteristics between different ion species (O+, O2+, and CO2+) and from the effect of different solar wind and interplanetary magnetic field (IMF) conditions.

  4. Ion channeling

    International Nuclear Information System (INIS)

    Erramli, H.; Blondiaux, G.

    1994-01-01

    Channeling phenomenon was predicted, many years ago, by stark. The first channeling experiments were performed in 1963 by Davies and his coworkers. Parallely Robinson and Oen have investigated this process by simulating trajectories of ions in monocrystals. This technique has been combined with many methods like Rutherford Backscattering Spectrometry (R.B.S.), Particles Induced X-rays Emission (P.I.X.E) and online Nuclear Reaction (N.R.A.) to localize trace elements in the crystal or to determine crystalline quality. To use channeling for material characterization we need data about the stopping power of the incident particle in the channeled direction. The ratios of channeled to random stopping powers of silicon for irradiation in the direction have been investigated and compared to the available theoretical results. We describe few applications of ion channeling in the field of materials characterization. Special attention is given to ion channeling combined with Charged Particle Activation Analysis (C.P.A.A.) for studying the behaviour of oxygen atoms in Czochralski silicon lattices under the influence of internal gettering and in different gaseous atmospheres. Association between ion channeling and C.P.A.A was also utilised for studying the influence of the growing conditions on concentration and position of carbon atoms at trace levels in the MOVPE Ga sub (1-x) Al sub x lattice. 6 figs., 1 tab., 32 refs. (author)

  5. Ion source

    International Nuclear Information System (INIS)

    1977-01-01

    The specifications of a set of point-shape electrodes of non-corrodable material that can hold a film of liquid material of equal thickness is described. Contained in a jacket, this set forms an ion source. The electrode is made of tungsten with a glassy carbon layer for insulation and an outer layer of aluminium-oxide ceramic material

  6. Diagnostics for studies of novel laser ion acceleration mechanisms

    OpenAIRE

    Senje, Lovisa; Yeung, Mark; Aurand, Bastian; Kuschel, Stephan; Rödel, Christian; Wagner, Florian; Li, Kun; Dromey, Brendan; Bagnoud, Vincent; Neumayer, Paul; Roth, Markus; Wahlström, Claes-Göran; Zepf, Matthew; Kuehl, Thomas; Jung, Daniel

    2014-01-01

    Diagnostic for investigating and distinguishing different laser ion acceleration mechanisms has been developed and successfully tested. An ion separation wide angle spectrometer can simultaneously investigate three important aspects of the laser plasma interaction: (1) acquire angularly resolved energy spectra for two ion species, (2) obtain ion energy spectra for multiple species, separated according to their charge to mass ratio, along selected axes, and (3) collect laser radiation reflecte...

  7. Biology Reflective Assessment Curriculum

    Science.gov (United States)

    Bayley, Cheryl Ann

    Often students and educators view assessments as an obligation and finality for a unit. In the current climate of high-stakes testing and accountability, the balance of time, resources and emphasis on students' scores related to assessment have been slanted considerably toward the summative side. This tension between assessment for accountability and assessment to inform teaching strains instruction and educators' ability to use that information to design learning opportunities that help students develop deeper conceptual understanding. A substantive body of research indicates that formative and reflective assessment can significantly improve student learning. Biology Reflective Assessment Curriculum (BRAC) examines support provided for high school science students through assessment practices. This investigation incorporates the usage of reflective assessments as a guiding practice for differentiated instruction and student choice. Reflective assessment is a metacognitive strategy that promotes self-monitoring and evaluation. The goals of the curriculum are to promote self-efficacy and conceptual understanding in students learning biology through developing their metacognitive awareness. BRAC was implemented in a high school biology classroom. Data from assessments, metacognitive surveys, self-efficacy surveys, reflective journals, student work, a culminating task and field notes were used to evaluate the effectiveness of the curriculum. The results suggest that students who develop their metacognitive skills developed a deeper conceptual understanding and improved feelings of self-efficacy when they were engaged in a reflective assessment unit embedded with student choice. BRAC is a tool for teachers to use assessments to assist students in becoming metacognitive and to guide student choice in learning opportunities.

  8. Novel wave/ion beam interaction approach to isotope separation

    International Nuclear Information System (INIS)

    Post, R.F.; Lowder, R.S.; Schwager, L.A.; Barr, W.L.; Warner, B.E.

    1993-02-01

    Numerical simulations and experimental studies have been made related to the possibility of employing an externally imposed electrostatic potential wave to separate isotopes. This wave/ion interaction is a sensitive function of the wave/ion difference velocity and for the appropriate wave amplitude and wave speed, a lighter faster isotope will be reflected by the wave to a higher energy while leaving heavier, slower isotopes virtually undisturbed in energy -- allowing subsequent ion separation by simple energy discrimination. In these experiments, a set of some 200 individual, electrodes, which surrounded a microamp beam of neon ions, was used to generate the wave. Measurements of the wave amplitudes needed for ion reflection and measurements of the final energies of those reflected ions are consistent with values expected from simple kinetic arguments and with the more detailed results of numeric simulations

  9. Ion-ion collisions and ion storage rings

    International Nuclear Information System (INIS)

    Mowat, J.R.

    1988-01-01

    Improved understanding of fundamental ion-ion interactions is expected to emerge from research carried out with ion storage rings. In this short survey the significant advantages and unique features that make stored ions useful targets for collision experiments are reviewed and discussed. It is pointed out that improvements to existing ion-ion experiments, as well as qualitatively new experiments, should occur over the next few years as ion storage rings become available for atomic physics. Some new experiments are suggested which are difficult if not impossible with present-day technology, but which seem feasible at storage rings facilities. (orig.)

  10. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2018-01-01

    Reflecting has a double meaning, mirroring and thinking. The seminar will investigate how these two meanings intervene in each other. As we perceive we are already in pre-refectory state, and thinking involves a lot of not only thoughts, but also of senses and sensing, wherefrom our thoughts star...

  11. Worship, Reflection, Empirical Research

    OpenAIRE

    Ding Dong,

    2012-01-01

    In my youth, I was a worshipper of Mao Zedong. From the latter stage of the Mao Era to the early years of Reform and Opening, I began to reflect on Mao and the Communist Revolution he launched. In recent years I’ve devoted myself to empirical historical research on Mao, seeking the truth about Mao and China’s modern history.

  12. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...

  13. Reflections on 21 years

    International Nuclear Information System (INIS)

    Eklund, S.; Mandel, H.; Teller, E.

    1977-01-01

    Personal reflections after twenty one years of nuclear power are presented by a number of those who were international figures in the nuclear energy field during that period. Lessons learnt, achievements, prospects and predictions for the future are discussed in eleven brief surveys. (U.K.)

  14. Reflection by Porro Prisms

    Science.gov (United States)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  15. Value reflected health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete

    2011-01-01

    This article examines the impact of a value-reflected approach in health education by demonstrating the nature of professional competence development connected to this approach. It is based on findings from two three-year health educational development projects carried out by school health nurses...... develop pedagogical competences in health education improving school childrens’ health....

  16. Reflection on Political Representation

    DEFF Research Database (Denmark)

    Kusche, Isabel

    2017-01-01

    This article compares how Members of Parliament in the United Kingdom and Ireland reflect on constituency service as an aspect of political representation. It differs from existing research on the constituency role of MPs in two regards. First, it approaches the question from a sociological viewp...

  17. Onward: Reflections on Mentoring

    Science.gov (United States)

    Williams, Kimberley Buster

    2018-01-01

    The author has been blessed with great mentors throughout her career. When she was invited to participate in the Leadership University of Mary Washington (UMW), a mentoring program at her institution, she did not hesitate to say yes. In this article, the author shares her reflections on mentoring.

  18. Interferometric reflection moire

    Science.gov (United States)

    Sciammarella, Cesar A.; Combell, Olivier

    1995-06-01

    A new reflection moire technique is introduced in this paper. The basic equations that relate the measurement of slopes to the basic geometric and optical parameters of the system are derived. The sensitivity and accuracy of the method are discussed. Examples of application to the study of silicon wafers and electronic chips are given.

  19. Reflection on robotic intelligence

    NARCIS (Netherlands)

    Bartneck, C.

    2006-01-01

    This paper reflects on the development or robots, both their physical shape as well as their intelligence. The later strongly depends on the progress made in the artificial intelligence (AI) community which does not yet provide the models and tools necessary to create intelligent robots. It is time

  20. Reflections on "La Esperanza"

    Science.gov (United States)

    Cortez, Anita

    2007-01-01

    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early…

  1. Reflecting on Writing Autobiography

    Science.gov (United States)

    Begg, Andy

    2011-01-01

    The following reflections relate to the reasons for and an approach to an autobiographic task, the notions that underpin it, and some thoughts about the quality and value of such a project. The focus was on the ways one views curriculum change over time; and the intention was to provide an example that others may sense as either familiar or at…

  2. Reflections on the Field.

    Science.gov (United States)

    Kauffman, James M.

    2003-01-01

    Reflections on the field of special education offer six ideas: (1) the value of science; (2) the continuing value of separate and special education for some students; (3) the continuing importance of prevention; (4) the importance of academic instruction; (5) the importance of social justice for the poor; and (6) a renewed emphasis on human…

  3. Reflections, 15 Years Later

    Science.gov (United States)

    Knox, George

    2016-01-01

    George Knox reflects on his 15-year career as president of Labette Community College in Parsons, Kansas. Knox writes that, as a first-time president coming into a brand new system, he was very fortunate to have many seasoned presidents and mentors in Kansas and from the American Association of Community Colleges' (AACC) Presidents Academy. He says…

  4. Investigating Global Ion and Neutral Atom Populations with IBEX and Voyager

    Science.gov (United States)

    Florinski, Vladimir

    2016-01-01

    The main objective of this project was to investigate pickup ion (PUI) production in the solar wind and heliosheath (the region between the termination shock and the heliopause) and compute the distributed energetic neutral atom fluxes throughout the helioshpere. The simulations were constrained by comparing the model output against observations from Ulysses, New Horizons, Voyager 1 and 2, and IBEX space probes. As evidenced by the number of peer reviewed journal publications resulting from the project (13 plus three submitted) and their citation rate (156 citations over three years), the project has made a lasting contribution to the field. The outcome is a significant improvement of our understanding of the pickup ion production and distribution in the distant heliosphere. The team has accomplished the entire set of tasks A-H set forth in the proposal. Namely, the transport modeling framework has been augmented with two populations of pickup ions (PUIs), the boundary conditions for the plasma and interstellar neutral hydrogen were verified against Ulysses and New Horizons PUI and an optimal set of velocity diffusion parameters established. The multi-component fluxes of PUIs were computed and isotropic velocity distributions generated for each cell in the computer simulation that covered the heliosphere from 1.5 AU to the heliopause. The distributions were carefully compared with in situ measurements at 3 AU (Ulysses), 12 AU (New Horizons), and 80-90 AU (Voyager 1 and 2) as well as those inferred from ENA fluxes measured by Cassini and IBEX (Wu et al., 2016). Some examples of modeldata comparison are shown in Figure 1. We have used coupled MHD-plasma and kinetic-neutral code to investigate the likely range of plasma and magnetic field parameters in the local interstellar medium (LISM), based on the assumption that the shape of the IBEX ribbon could be used to determine the orientation of the interstellar magnetic field. While the magnetic field is believed to be

  5. Enhanced electron/fuel-ion equilibration through impurity ions: Studies applicable to NIF and Omega

    Science.gov (United States)

    Petrasso, R. D.; Sio, H.; Kabadi, N.; Lahmann, B.; Simpson, R.; Parker, C.; Frenje, J.; Gatu Johnson, M.; Li, C. K.; Seguin, F. H.; Rinderknecht, H.; Casey, D.; Grabowski, P.; Graziani, F.; Taitano, W.; Le, A.; Chacon, L.; Hoffman, N.; Kagan, G.; Simakov, A.; Zylstra, A.; Rosenberg, M.; Betti, R.; Srinivasan, B.; Mancini, R.

    2017-10-01

    In shock-driven exploding-pushers, a platform used extensively to study multi-species and kinetic effects, electrons and fuel ions are far out of equilibrium, as reflected by very different temperatures. However, impurity ions, even in small quantities, can couple effectively to the electrons, because of a Z2 dependence, and in turn, impurity ions can then strongly couple to the fuel ions. Through this mechanism, electrons and fuel-ions can equilibrate much faster than they otherwise would. This is a quantitative issue, depending upon the amount and Z of the impurity. For NIF and Omega, we consider the role of this process. Coupled non-linear equations, reflecting the temperatures of the three species, are solved for a range of conditions. Consideration is also given to ablatively driven implosions, since impurities can similarly affect the equilibration. This work was supported in part by DOE/NNSA DE-NA0002949 and DE-NA0002726.

  6. Being a reflective teacher——reflection on group management

    Institute of Scientific and Technical Information of China (English)

    Pan; Lehui

    2015-01-01

    <正>Introduction According to Pollard and Triggs(1997),reflective teaching is a process through which the capacity to make such professional judgments can be developed and maintained.Then what is a reflective teacher?Reflective teacher is someone who reflects systematically on her practice in a constant attempt to improve

  7. Ethical reflection and psychotherapy.

    Science.gov (United States)

    Vyskocilová, Jana; Prasko, Jan

    2013-01-01

    Theories of ethics and ethical reflection may be applied to both theory and practice in psychotherapy. There is a natural affinity between ethics and psychotherapy. Psychotherapy practice is concerned with human problems, dilemmas and emotions related to both one's own and other people's values. Ethics is also concerned with dilemmas in human thinking and with how these dilemmas reflect other individuals' values. Philosophical reflection itself is not a sufficient basis for the ethics of psychotherapy but it may aid in exploring attitudes related to psychotherapy, psychiatry and health care. PubMed, Web of Science and Scopus databases were searched for articles containing the keywords "psychotherapy", "ethics", "therapeutic relationship" and "supervision". The search was conducted by repeating the terms in various combinations without language or time restrictions. Also included were data from monographs cited in reviews. The resulting text is a review with conclusions concerning ethical aspects of psychotherapy. The ability to behave altruistically, sense for justice and reciprocity and mutual help are likely to be genetically determined as dispositions to be later developed by upbringing or to be formed or deformed by upbringing. Early experiences lead to formation of ethical attitudes which are internalized and then applied to both one's own and other people's behavior. Altruistic behavior has a strong impact on an individual's health and its acceptance may positively influence the pathophysiological mechanisms underlying numerous diseases. Ethical theory and reflection, however, may be applied to both theory and practice of psychotherapy in a conscious, targeted and thoughtful manner. In everyday practice, psychotherapists and organizations must necessarily deal with conscious conflicts between therapeutic possibilities, clients' wishes, their own as well as clients' ideas and the real world. Understanding one's own motives in therapy is one of the aims of a

  8. An analysis of plasma ion toroidal rotation during large amplitude MHD activity in JET

    International Nuclear Information System (INIS)

    Snipes, J.A.; Esch, H.P.L. de; Lazzaro, E.; Stork, D.; Hellermann, M. von; Galvao, R.; Hender, T.C.; Zasche, D.

    1989-01-01

    A detailed study of plasma ion toroidal rotation in JET during large amplitude MHD activity has revealed a strong viscous force that couples plasma ions to MHD modes. Depending on the MHD modes present, this force can couple across all of the plasma cross section, across only the central region, roughly within the q=1 surface, or across only the outer region outside the q=1.5 surface. The force acts to flatten the ion toroidal rotation frequency profile, measured by the JET active charge exchange spectroscopy diagnostic, across the coupled region of plasma. The frequency of rotation in this region agrees with the MHD oscillation frequency measured by magnetic pick-up coils at the wall. The strength of the force between the ions and modes becomes evident during high power NBI when the mode locks and drags the ion toroidal rotation frequency to zero, within the errors of the measurements. The present theories of plasma rotation either ignore MHD effects entirely, consider only moderate n toroidal field ripple, or low n ripple effects. (author) 7 refs., 3 figs

  9. Electron capture in ion atom and ion-ion collisions

    International Nuclear Information System (INIS)

    Barat, M.

    1986-01-01

    Electron capture (EC) by positive ions in collision with various targets has remained one of the most important subjects of research since the early 30's. From a theoretical point of view, EC is obviously a coupled 3-body problem: at least two cores and an active electron that jumps between them. Practical interest in EC arose in a variety of fields. Recently a renewed interest arose from the physics of thermonuclear fusion, where capture by highly charged ionic impurities were found to be an important process in tokamak devices. For that reasons, a number of reviews were devoted to this subject during the past years, including lectures given in various NATO advanced science institutes. The aim of this lecture is not at all to add a new review to this list, but (i) to summarize the very basis of the present theoretical approaches at low and moderate collision energy, (ii) to pinpoint some crucial difficulties in the theoretical treatment, (iii) to select specific examples which, to the taste of the author, reflect some present practical interest, or some significant advances. 48 references, 38 figures, 1 table

  10. Bragg reflection program

    International Nuclear Information System (INIS)

    Lynn, J.W.

    This user's guide to the Bragg Reflection Program (BRP) is in the nature of an informal report. The general purpose of BRP is to scan a series of Bragg reflections automatically in order to obtain profiles and integrated intensities. The program is used in conjunction with the SUPERVISOR and READ packages, and the procedures for using it are similar to those for the Triple-Axis Control program. All the general features of the system, SUPERVISOR and READ packages as described in the Spectrometer Control Systems User's Guide are preserved. The presentation assumes that the reader is familiar with these. Sections are given on the READ package, execution and use, error messages, and output. A few sample problems are shown. (1 figure) (U.S.)

  11. Reflections on Active Networking

    Science.gov (United States)

    2005-01-01

    with a Software Switch for Active Networks ”. We had initially called the project “ SoftSwitch ”, but after some concerns David Farber raised that this...Reflections on Active Networking Jonathan M. Smith CIS Department, University of Pennsylvania jms@cis.upenn.edu Abstract Interactions among...telecommunications networks , computers, and other peripheral devices have been of interest since the earliest distributed computing systems. A key

  12. Clinical linguistics: conversational reflections.

    Science.gov (United States)

    Crystal, David

    2013-04-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference participants during that time.

  13. Superradiance or total reflection?

    CERN Document Server

    László, András

    2014-01-01

    Numerical evolution of massless scalar fields on Kerr background is studied. The initial data specifications are chosen to have compact support separated from the ergoregion and to yield nearly monochromatic incident wave packets. The initial data is also tuned to maximize the effect of superradiance. Evidences are shown indicating that instead of the anticipated energy extraction from black hole the incident radiation fail to reach the ergoregion rather it suffers a nearly perfect reflection.

  14. Ion Beam Extraction by Discrete Ion Focusing

    DEFF Research Database (Denmark)

    2010-01-01

    An apparatus (900) and methods are disclosed for ion beam extraction. In an implementation, the apparatus includes a plasma source (or plasma) (802) and an ion extractor (804). The plasma source is adapted to generate ions and the ion extractor is immersed in the plasma source to extract a fracti...

  15. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  16. Reflection Revisited: The Class Collage

    Science.gov (United States)

    Sommers, Jeff

    2011-01-01

    Through the regular use of what Donald Schon has termed reflection-in-action and reflection-on-action, students can learn to improve their "reflection-in-presentation," in Kathleen Blake Yancey's term. Students are often asked to do this type of reflection-in-presentation as a capstone to first-year or basic writing courses. However, a number of…

  17. Reflection as Self-Assessment

    Science.gov (United States)

    Pappas, Marjorie L.

    2010-01-01

    In this article, the author discusses how reflection can be used as self-assessment. Reflection involves not only thinking about a learning experience, but also questioning parts of the experience. Reflection is thinking about what one knows from the learning experience, what one might do differently the next time. Reflection is wondering about…

  18. Inelastic collisions of heavy ions and their reaction mechanisms; Collisions inelastiques d'ions lourds et mecanismes de reaction

    Energy Technology Data Exchange (ETDEWEB)

    Scarpaci, J.A

    2004-06-01

    This work is dedicated to the study of inelastic collisions of heavy ions. Most experiments took place in Ganil facility. The 2 first chapters introduce the notion of inelastic scattering of heavy ions. The third chapter deals with target excitation, giant monopolar or dipolar or quadrupolar resonances ant the multi-phonon concept and presents relevant experimental results from the Ca{sup 40} + Ca{sup 40} nuclear reaction at 50 MeV/A. The fourth chapter is dedicated to nuclear processes involved in inelastic collisions: pick-up break-up mechanisms, the angular distribution of emitted protons and the towing mode. These notions are applied to the reaction Zr{sup 90}(Ar{sup 40}, Ar{sup 40}'). The fifth chapter presents the solving of the time dependent Schroedinger equation (TDSE) applied to the wave function of a particle plunged in a variable potential. TDSE solving is applied to the break-up of Be{sup 11}. These calculations have been validated by comparing them with experimental results from the nuclear reaction Ti{sup 48}(Be{sup 11}, Be{sup 10} + n + {gamma}) that is described in the chapter 6. The last chapter presents the advantages of inelastic scattering considered as a tool to study exotic nuclei.

  19. Particle reflection along the magnetic field in nonlinear magnetosonic pulses

    Science.gov (United States)

    Ohsawa, Yukiharu

    2017-11-01

    Reflection of electrons and positrons in oblique, nonlinear magnetosonic pulses is theoretically analyzed. With the use of the parallel pseudo potential F, which is the integral of the parallel electric field along the magnetic field, a simple equation for reflection conditions is derived, which shows that reflection along the magnetic field is caused by two forces: one arising from the parallel pseudo potential multiplied by the particle charge and the other from the magnetic mirror effect. The two forces push electrons in the opposite directions. In compressive solitons, in which the magnetic field is intensified, electrons with large magnetic moments can be reflected by the magnetic mirror effect, whereas in rarefactive solitons, in which the magnetic field is weaker than outside, electrons with small magnetic moments can be reflected by the parallel pseudo potential. Although F is basically positive and large in shock waves, it occasionally becomes negative in some regions behind the shock front in nonstationary wave evolution. These negative spikes of F can reflect electrons. In contrast to the case of electrons, the two forces push positrons in the same direction. For this reason, compressive solitons in an electron-positron-ion plasma reflect a large fraction of positrons compared with electrons, whereas rarefactive solitons will reflect no positrons. A shock wave can reflect a majority of positrons with its large F. However, in a pure electron-positron plasma, in which F becomes zero, positron reflection will rarely occur.

  20. ION GUN

    Science.gov (United States)

    Dandl, R.A.

    1961-10-24

    An ion gun is described for the production of an electrically neutral ionized plasma. The ion gun comprises an anode and a cathode mounted in concentric relationship with a narrow annulus between. The facing surfaces of the rear portions of the anode and cathode are recessed to form an annular manifold. Positioned within this manifold is an annular intermediate electrode aligned with the an nulus between the anode and cathode. Gas is fed to the manifold and an arc discharge is established between the anode and cathode. The gas is then withdrawn from the manifold through the annulus between the anode and cathode by a pressure differential. The gas is then ionized by the arc discharge across the annulus. The ionized gas is withdrawn from the annulus by the combined effects of the pressure differential and a collimating magnetic field. In a 3000 gauss magnetic field, an arc voltage of 1800 volts, and an arc current of 0.2 amp, a plasma of about 3 x 10/sup 11/ particles/cc is obtained. (AEC)

  1. Heavy ions

    CERN Multimedia

    CERN. Geneva; Antinori, Federico

    2001-01-01

    Colliding two heavy nuclei at ultrarelativistic energies allows to create in the laboratory a bulk system with huge density, pressure and temperature and to study its properties. It is estimated that in Pb-Pb collisions at CERN-SPS we reach over an appreciable volume an energy density which exceeds by more than a factor 20 that of normal nuclear matter. At such densities, the hadrons are so closely packed that they interpenetrate; novel physics phenomena are expected to appear. QCD predicts that under such conditions a phase transition from a system composed of colourless hadrons to a Quark-Gluon Plasma (QGP) should occur. A rich ultrarelativistic heavy-ion physics programme is under way both at BNL-AGS and at CERN-SPS since 1986. The results obtained so far have led CERN to officially announce evidence for a new state of matter last year. A long-range programme of heavy-ion physics at higher energies is under way (BNL-RHIC) and in preparation (CERN-LHC). These lectures are meant as an introduction to the phy...

  2. Heavy ions

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit

    2002-01-01

    Colliding two heavy nuclei at ultrarelativistic energies allows to create in the laboratory a bulk system with huge density, pressure and temperature and to study its properties. It is estimated that in Pb-Pb collisions at CERN-SPS we reach over an appreciable volume an energy density which exceeds by more than a factor 20 that of normal nuclear matter. At such densities, the hadrons are so closely packed that they interpenetrate; novel physics phenomena are expected to appear. QCD predicts that under such conditions a phase transition from a system composed of colourless hadrons to a Quark-Gluon Plasma (QGP) should occur. A rich ultrarelativistic heavy-ion physics programme is under way both at BNL-AGS and at CERN-SPS since 1986. The results obtained so far have led CERN to officially announce evidence for a new state of matter last year. A long-range programme of heavy-ion physics at higher energies is under way (BNL-RHIC) and in preparation (CERN-LHC). These lectures are meant as an introduction to the phy...

  3. Seismic reflection imaging, accounting for primary and multiple reflections

    Science.gov (United States)

    Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel

    2015-04-01

    Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are

  4. A fiberoptic reflection oximeter.

    Science.gov (United States)

    Landsman, M L; Knop, N; Kwant, G; Mook, G A; Zijlstra, W G

    1978-03-20

    A catheter tip oximeter is described consisting of a cardiac catheter containing optical fibers, and incandescent light source, a light detection unit and a processing unit. Half of the optical fibers guide the light to the blood at the tip of the catheter, the other half the backscattered (reflected) light to the detection unit. The detection unit contains a dichroic mirror, transmitting most of the light with lambda less than 800 nm and reflecting most of the light with lambda greater than 900 nm, thus splitting the light into two beams. These pass through interference filters with nominal wavelengths of 640 and 920 nm respectively, and are focused on silicium barrier layer photocells. The photocell signals are amplified and fed into a divider giving the ratio of measuring (R640) and compensating (R920) photocell output. The relationship between log R640/R920 and oxygen saturation is represented by a slightly curved line. The relation may be linearized by subtracting a constant voltage from the divided output before taking the logarithm. The slope of the calibration line is dependent on the total haemoglobin concentration. Nonetheless an average calibration line can be used between 70 and 100% oxygen saturation. For 78 measurements of pig blood samples in this range (haemoglobin concentration between 96 and 161 g.1(-1)), the standard deviation of the difference between the fiberoptic oximeter and a Radiometer OSM1 oxygen saturation meter was 1.9% saturation, for 152 samples over the entire saturation range the standard deviation of the difference was 3.1% saturation. The influence of the flow velocity of blood on the light reflection depends on wavelength as well as on oxygen saturation. Therefore, complete compensation for the flow effect is not possible by simple means.

  5. Reflections on preventive medicine.

    Science.gov (United States)

    Miettinen, Olli S

    2014-10-01

    Having thought much about medicine in my career-long effort to understand it and the research for its advancement, I have come to views rather different form the now-prevailing ones in respect to what preventive medicine is about; what epidemiology is in relation to preventive medicine; what distinguishes preventive medicine in preventive healthcare at large; the relation of preventive medicine to public health; the concept of health promotion; and also the core principles of preventive medicine. All of these views I set forth in this article, for the readers' critical reflection. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Measurement of the mean radial position of a lead ion beam in the CERN PS

    CERN Document Server

    Belleman, J; González, J; Johnston, S; Schulte, E C; Thivent, E

    1996-01-01

    The intensity of the lead ion beam in the PS, nominally 4×108 charges of Pb53+ per bunch, is too low for the closed orbit measurement system. However, for successful acceleration it is sufficient to know the mean radial position (MRP). A system was thus designed for simultaneous acquisition of revolution frequency and magnetic field. The frequency measurement uses a direct digital synthesiser (DDS), phase-locked to the beam signal from a special high-sensitivity pick-up. The magnetic field is obtained from the so-called B-train. From these two values, the MRP is calculated. The precision depends on the frequency measurement and on the accuracy of the value for the magnetic field. Furthermore, exact knowledge of the transition energy is essential. This paper describes the hardware and software developed for the MRP system, and discusses the issue of calibration, with a proton beam, of the B measurement.

  7. Transfer reactions with very heavy ions. Quarterly report 3. quarter 1987

    International Nuclear Information System (INIS)

    Juutinen, Sakari.

    1988-03-01

    This thesis deals with the reaction mechanism of the few-nucleon transfer reactions between the 58 Ni projectiles and the Dy targets. A series of transfer experiments utilizing the particle-γ coincidence technique was performed. Particle detection was used to give the scattering angles of two reaction products and the reaction channel was selected by the discrete γ-rays in the Ge detectors. Total γ-ray energy and multiplicity distributions were measured by the Spin Spectrometer. Total γ-ray energy and multiplicity distributions, γ-ray spectra obtained by the Ge and NaI detectors and angular distributions of the projectile-like ions are discussed. For one- and two-neutron transfer the experimental results provide direct evidence of a cold mechanism populating high-spin states near the yrast line. A schematic model for the transfer mechanism is proposed. This model accounts for the prominent features of one- and two-neutron pickup

  8. Matter reflects Antimatter

    CERN Document Server

    Bianconi, A.; Cristiano, A.; Leali, M.; Lodi Rizzini, E.; Venturelli, L.; Zurlo, N.

    2008-01-01

    It is common belief that the interaction between antimatter and ordinary solid matter is dominated by annihilation. However, non-destructive processes may play a relevant role too. One century ago E. Rutherford wrote about the "diffuse reflection" of alpha and beta particles by thin layers of different metals: "The observations ... of Geiger and Marsden on the scattering of alpha rays indicate that some of the alpha particles must suffer a deflexion of more than a right angle at a single encounter.... It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative". Although the theory of electromagnetic scattering is in first approximation independent of the relative sign of the colliding particles, in the case where projectile antiprotons are shot against a wall of solid matter the Rutherford diffuse reflection mechanism competes with the annihilation process. So it is not obvious at all that a relevant part of an antiproton beam...

  9. Reflection, Interrogatory, Provocation

    International Nuclear Information System (INIS)

    Carnes, W.E.

    2016-01-01

    This invited paper advances a framing context for considering next steps in HOF and organizational culture in light of the presentations and discussions that occur during the conference. Many of the contributions during the conference will represent results of scholarly research, structured investigations, or formal organizational improvement efforts. This contribution is intended as informal reflection by a 40-year nuclear veteran on themes from other presentations considering questions such as: ''Where do we think we are?, Are we better off as an industry based on what we have done?, Where do we think we need to go?, What do we think we need to do?, and, Why do we think these things?'' Our coming together on this occasion marks 30 years since the publication of INSAG-l. As we reflect on the past, perhaps it is time to pose a series of questions. Are we sustainers of a mature technology that is in some places declining and being replaced by other energy sources? If we consider nuclear a mature technology, should we focus most on operational excellence with renewed attention to managing the unexpected? Or, is innovation still a vital part of our industry?

  10. Diagnostics for studies of novel laser ion acceleration mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Senje, Lovisa; Aurand, Bastian; Wahlström, Claes-Göran [Department of Physics, Lund University, P. O. Box 118, S-221 00 Lund (Sweden); Yeung, Mark; Kuschel, Stephan; Rödel, Christian [Helmholtz-Institut Jena, D-07743 Jena (Germany); Wagner, Florian; Roth, Markus [Technische Universität Darmstadt, D-64289 Darmstadt (Germany); Li, Kun; Neumayer, Paul [ExtreMe Matter Institut, D-64291 Darmstadt (Germany); Dromey, Brendan; Jung, Daniel [Department of Physics and Astronomy, Queen' s University, Belfast BT7 1NN (United Kingdom); Bagnoud, Vincent [Helmholtz-Institut Jena, D-07743 Jena (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Zepf, Matthew [Helmholtz-Institut Jena, D-07743 Jena (Germany); Department of Physics and Astronomy, Queen' s University, Belfast BT7 1NN (United Kingdom); Kuehl, Thomas [ExtreMe Matter Institut, D-64291 Darmstadt (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt (Germany); Universität Mainz, D-55099 Mainz (Germany)

    2014-11-15

    Diagnostic for investigating and distinguishing different laser ion acceleration mechanisms has been developed and successfully tested. An ion separation wide angle spectrometer can simultaneously investigate three important aspects of the laser plasma interaction: (1) acquire angularly resolved energy spectra for two ion species, (2) obtain ion energy spectra for multiple species, separated according to their charge to mass ratio, along selected axes, and (3) collect laser radiation reflected from and transmitted through the target and propagating in the same direction as the ion beam. Thus, the presented diagnostic constitutes a highly adaptable tool for accurately studying novel acceleration mechanisms in terms of their angular energy distribution, conversion efficiency, and plasma density evolution.

  11. Diagnostics for studies of novel laser ion acceleration mechanisms

    International Nuclear Information System (INIS)

    Senje, Lovisa; Aurand, Bastian; Wahlström, Claes-Göran; Yeung, Mark; Kuschel, Stephan; Rödel, Christian; Wagner, Florian; Roth, Markus; Li, Kun; Neumayer, Paul; Dromey, Brendan; Jung, Daniel; Bagnoud, Vincent; Zepf, Matthew; Kuehl, Thomas

    2014-01-01

    Diagnostic for investigating and distinguishing different laser ion acceleration mechanisms has been developed and successfully tested. An ion separation wide angle spectrometer can simultaneously investigate three important aspects of the laser plasma interaction: (1) acquire angularly resolved energy spectra for two ion species, (2) obtain ion energy spectra for multiple species, separated according to their charge to mass ratio, along selected axes, and (3) collect laser radiation reflected from and transmitted through the target and propagating in the same direction as the ion beam. Thus, the presented diagnostic constitutes a highly adaptable tool for accurately studying novel acceleration mechanisms in terms of their angular energy distribution, conversion efficiency, and plasma density evolution

  12. Radiation induced currents in mineral-insulated cables and in pick-up coils: model calculations and experimental verification in the BR1 reactor

    Science.gov (United States)

    Vermeeren, Ludo; Leysen, Willem; Brichard, Benoit

    2018-01-01

    Mineral-insulated (MI) cables and Low-Temperature Co-fired Ceramic (LTCC) magnetic pick-up coils are intended to be installed in various position in ITER. The severe ITER nuclear radiation field is expected to lead to induced currents that could perturb diagnostic measurements. In order to assess this problem and to find mitigation strategies models were developed for the calculation of neutron-and gamma-induced currents in MI cables and in LTCC coils. The models are based on calculations with the MCNPX code, combined with a dedicated model for the drift of electrons stopped in the insulator. The gamma induced currents can be easily calculated with a single coupled photon-electron MCNPX calculation. The prompt neutron induced currents requires only a single coupled neutron-photon-electron MCNPX run. The various delayed neutron contributions require a careful analysis of all possibly relevant neutron-induced reaction paths and a combination of different types of MCNPX calculations. The models were applied for a specific twin-core copper MI cable, for one quad-core copper cable and for silver conductor LTCC coils (one with silver ground plates in order to reduce the currents and one without such silver ground plates). Calculations were performed for irradiation conditions (neutron and gamma spectra and fluxes) in relevant positions in ITER and in the Y3 irradiation channel of the BR1 reactor at SCK•CEN, in which an irradiation test of these four test devices was carried out afterwards. We will present the basic elements of the models and show the results of all relevant partial currents (gamma and neutron induced, prompt and various delayed currents) in BR1-Y3 conditions. Experimental data will be shown and analysed in terms of the respective contributions. The tests were performed at reactor powers of 350 kW and 1 MW, leading to thermal neutron fluxes of 1E11 n/cm2s and 3E11 n/cm2s, respectively. The corresponding total radiation induced currents are ranging from

  13. Exposure of in-pram babies to airborne particles during morning drop-in and afternoon pick-up of school children.

    Science.gov (United States)

    Kumar, Prashant; Rivas, Ioar; Sachdeva, Lovish

    2017-05-01

    In-pram babies are more susceptible to air pollution effects, yet studies assessing their exposure are limited. We measured size-resolved particle mass (PMC; 0.25-32 μm) and number (PNC; 0.2-1 μm) concentrations on a 2.7 km route. The instruments were placed inside a baby pram. The route passed through 4 traffic intersections (TIs) and a bus stand. A total of ∼87 km road length was covered through 64 trips, made during school drop-in (morning) and pick-up (afternoon) hours. The objectives were to assess PMC and PNC exposure to in-pram babies at different route segments, understand their physicochemical characteristics and exposure differences between in-pram babies and adults carrying them. Over 5-fold variability (14.1-78.2 μg m -3 ) was observed in PMCs. Small-sized particles, including ultrafine particles, were always higher by 66% (PM 1 ), 29% (PM 2.5 ) and 31% (PNC) during the morning than afternoon. Coarse particles (PM 2.5-10 ) showed an opposite trend with 70% higher concentration during afternoon than morning. TIs emerged as pollution hotspots for all the particle types. For example, PM 2.5 , PM 2.5-10 and PNCs during the morning (afternoon) at TIs were 7 (10)%, 19 (10)% and 68 (62)% higher, respectively, compared with the rest of the route. Bus stand was also a section of enhanced exposure to PNC and PM 2.5 , although not so much for PM 2.5-10 . EDX analyses revealed Cl, Na and Fe as dominant elements. Road salt might be a source of NaCl due to de-icing during the measurements while Fe contributed by non-exhaust emissions from brake abrasion. The respiratory deposition rates imitated the trend of PMC, with higher doses of coarse and fine particles during the afternoon and morning runs, respectively. Special protection measures during conveyance of in-pram babies, especially at pollution hotspots such as traffic intersections and bus stands, could help to limit their exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

    International Nuclear Information System (INIS)

    Okuyama, F.; Fujimoto, Y.

    1986-01-01

    Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

  15. Reflection and Non-Reflection of Particle Wavepackets

    Science.gov (United States)

    Cox, Timothy; Lekner, John

    2008-01-01

    Exact closed-form solutions of the time-dependent Schrodinger equation are obtained, describing the propagation of wavepackets in the neighbourhood of a potential. Examples given include zero reflection, total reflection and partial reflection of the wavepacket, for the sech[superscript 2]x/a, 1/x[superscript 2] and delta(x) potentials,…

  16. Reflecting Contemporary Design Research

    DEFF Research Database (Denmark)

    Engholm, Ida

    2017-01-01

    In recent years, design research has been the object of growing attention in universities and academies throughout the world. The present paper addresses the heterogeneous character of design research and the current need for reflection on the various approaches and interests. For this purpose......, the paper follows two steps. First, it proposes a categorization of the field in the form of a position model. The paper’s underlying assumption is that design research as a discipline exists in many different forms that cannot necessarily be brought together under one common academic research tradition......; instead it is necessary to attempt to define the field in order to initiate discussions about what constitutes the various research bases for design. Second, the paper discusses the implication for future design research when it is an interdisciplinary field that involves many disciplines, mindsets...

  17. The Reflective Methodologists

    DEFF Research Database (Denmark)

    Kjær, Bjørg

    2013-01-01

    In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways. In this ......In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways...... in which the practical sense and tacit knowledge are related to questions of power and social actors’ strategies for positioning themselves within a social space. This demands a particular focus on the historical effect of the concept of ‘the reflective practitioner’ as a symbolic marker of identity...

  18. Reflections on SLAP

    International Nuclear Information System (INIS)

    Cooke, Roger

    1997-01-01

    The SLAP data bases represent a major step forward in the reliability analysis of passive components. The present reflections are motivated by draft documentation for SLAP and have profited greatly from discussions with the SLAP team. We collect a number of remarks and suggestions: The use of event and failure fields to organize the data seems sensible and feasible, from a data analysis viewpoint. Influence factors, i. e. environmental influences which are affected by plant operations, are clearly important yet very difficult to accommodate in any straightforward data analysis methodology. We would welcome a serious effort to estimate the exposure in the various exposure cells. These estimates would not be based on failure records, but on knowledge of plant design and operations. Quantitative expert judgement might be a viable alternative to a massive review of all plants in the SLAP data base

  19. Reflections on Conformal Spectra

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  20. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson

    2012-11-01

    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  1. Reflections on Student Persistence

    Directory of Open Access Journals (Sweden)

    Vincent Tinto

    2017-07-01

    Full Text Available The Feature for this issue Reflections on Student Persistence has been prepared by Professor Vincent Tinto, Distinguished University Professor Emeritus at Syracuse University, United States of America (USA and a longtime friend and supporter of STARS. Vincent explores the case for motivation to be considered as a significant aspect of the tertiary student psyche by drawing on theoretical frameworks, research and practical experiences related to the issue. He synthesises this extensive, detailed, rich but often somewhat impenetrable data into a trilogy of clear and credible key dimensions of the motivation construct student self efficacy, sense of belonging and perceived value of the curriculum. This interpretation of the literature is a personal but informed reflection and is a timely piece which highlights the breadth and profundity of the presentations at this year's conference in Adelaide, Australia where students in all their diversity are central to our focus on enhancing the student experience. In this opening article, Vincent refers directly to the STARS papers selected for this Conference issue of the Journal which also address the importance of student persistence, self-efficacy and building the sense of belonging within their own institutional communities (Fernandes, Ford, Rayner & Pretorius; Kahu, Nelson, & Picton; McFarlane, Spes-Skrbis & Taib; Naylor; Smallhorn. Echoing his position on social justice and his advocacy for underserved students, Vincent reminds us that educational equity gaps still exist, and he encourages us to see the issue of persistence through the eyes of the students to support their perseverance and completion and thereby help reduce educational disadvantage.

  2. Ion beam monitoring

    International Nuclear Information System (INIS)

    McKinney, C.R.

    1980-01-01

    An ion beam analyzer is specified, having an ion source for generating ions of a sample to be analyzed, means for extracting the sample ions, means for focusing the sample ions into a beam, separation means positioned along the ion beam for selectively deflecting species of ions, and means for detecting the selected species of ions. According to the specification, the analyzer further comprises (a) means for disabling at least a portion of the separation means, such that the ion beam from the source remains undeflected; (b) means located along the path of the undeflected ion beam for sensing the sample ions; and (c) enabling means responsive to the sensing means for automatically re-enabling the separation means when the sample ions reach a predetermined intensity level. (author)

  3. Reflective Practices for Teacher Education

    Directory of Open Access Journals (Sweden)

    Paulus Kuswandono

    2017-01-01

    Full Text Available Studies on reflective practice in teacher education are increasingly getting more attention at least in the last 2 decades. This article discusses concepts of reflection and how it is implemented in educating pre-service teachers on their early stage of professional learning. The purposes of doing the reflection for pre-service teachers are not only for illuminating their professional learning experiences, but also to critically reflect their vocation as teachers, including the values which may be dictated to them through rigid regulations. Reflection in teacher education is crucial as it connects well with learning in that learners use reflection to exercise their mind and to evaluate their learning experiences. Besides, this article also highlights some perceived difficulties to implement reflective practice, as well as ways how to promote reflection.   DOI: https://doi.org/10.24071/llt.2012.150102

  4. Guided and Unguided Student Reflections

    OpenAIRE

    Matheson, Amanda; Wood, Laura; Franklin, Scott V.

    2017-01-01

    Self-reflection is important metacognitive skill, enabling students to build coherence into their learning and embed content in a broader context. While various pedagogical techniques exist to encourage student reflection, little research has examined the differences between formally guided, partially guided and unguided reflections. This study focuses on student responses to online Guided Reflection Forms (GRFs) from students in a first-semester non-physics class and, separately, a sophomore...

  5. Students’ Learning through Reflective Journaling

    OpenAIRE

    Alvyda Liuolienė; Regina Metiūnienė

    2011-01-01

    The aim of the article is to get acquainted with the types of journals used in education to help students to learn. The paper presents some ways of fostering student’s learning through reflective journaling. It also describes the key aspects of a new method ARRIVE cycle in connection with teachers preparation to use reflective journals in a classroom. The article also presents self-assessment in reflective journaling and students’ need to self-evaluate their learning process. Reflective journ...

  6. Mode conversion of fast Alfvacute en waves at the ion endash ion hybrid resonance

    International Nuclear Information System (INIS)

    Ram, A.K.; Bers, A.; Schultz, S.D.; Fuchs, V.

    1996-01-01

    Substantial radio-frequency power in the ion-cyclotron range of frequencies can be effectively coupled to a tokamak plasma from poloidal current strap antennas at the plasma edge. If there exists an ion endash ion hybrid resonance inside the plasma, then some of the power from the antenna, delivered into the plasma by fast Alfvacute en waves, can be mode converted to ion-Bernstein waves. In tokamak confinement fields the mode-converted ion-Bernstein waves can damp effectively and locally on electrons [A. K. Ram and A. Bers, Phys. Fluids B 3, 1059 (1991)]. The usual mode-conversion analysis that studies the propagation of fast Alfvacute en waves in the immediate vicinity of the ion endash ion hybrid resonance is extended to include the propagation and reflection of the fast Alfvacute en waves on the high magnetic-field side of the ion endash ion hybrid resonance. It is shown that there exist plasma conditions for which the entire fast Alfvacute en wave power incident on the ion endash ion hybrid resonance can be converted to ion-Bernstein waves. In this extended analysis of the mode conversion process, the fast Alfvacute en waves can be envisioned as being coupled to an internal plasma resonator. This resonator extends from the low magnetic-field cutoff near the ion endash ion hybrid resonance to the high magnetic-field cutoff. The condition for 100% mode conversion corresponds to a critical coupling of the fast Alfvacute en waves to this internal resonator. As an example, the appropriate plasma conditions for 100% mode conversion are determined for the Tokamak Fusion Test Reactor (TFTR) [R. Majeski et al., Proceedings of the 11th Topical Conference on RF Power in Plasmas, Palm Springs (American Institute of Physics, New York, 1995), Vol. 355, p. 63] experimental parameters. copyright 1996 American Institute of Physics

  7. Steady state ion acceleration by a circularly polarized laser pulse

    International Nuclear Information System (INIS)

    Zhang Xiaomei; Shen Baifei; Cang Yu; Li Xuemei; Jin Zhangying; Wang Fengchao

    2007-01-01

    The steady state ion acceleration at the front of a cold solid target by a circularly polarized flat-top laser pulse is studied with one-dimensional particle-in-cell (PIC) simulation. A model that ions are reflected by a steady laser-driven piston is used by comparing with the electrostatic shock acceleration. A stable profile with a double-flat-top structure in phase space forms after ions enter the undisturbed region of the target with a constant velocity

  8. Electrostatic ion confinement in a magnetic mirror field

    International Nuclear Information System (INIS)

    Nishida, Y.; Kawamata, S.; Ishii, K.

    1976-08-01

    The electrostatic ion stoppering at the mirror point is demonstrated experimentally in a magnetic mirror field. The ion losses from the mirror throat are decreased to about 15% of the initial losses in a rather high plasma density (10 10 0 13 cm -3 ). It is discussed as a confinement mechanism of ions that particles are reflected back adiabatically at the throat of the magnetic mirror field supplemented by DC electric field. (auth.)

  9. Reflection in Russian Educational Psychology.

    Science.gov (United States)

    Nelissen, Jo M. C.; Tomic, Welko

    This paper discusses the cultural-historical school founded by Vygotsky, Luria, and Leontiev as the theoretical background of Russian educational psychologists who have been studying how children learn to reflect. Two approaches to reflection are examined within the cultural-historical tradition: first, reflection--like other higher psychological…

  10. Reflective Practice: Origins and Interpretations

    Science.gov (United States)

    Reynolds, Michael

    2011-01-01

    The idea of reflection is central to the theory and practice of learning--especially learning which is grounded in past or current experience. This paper proposes a working definition of reflection and reviews its origins and recent developments. The author also provides an account of "critical reflection", including its rationale and…

  11. Teachers’ way of reflecting

    DEFF Research Database (Denmark)

    Lund, Lea

    2016-01-01

    This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose of t......’ reflections on practice. Based on this model, the paper provides a proposal regarding how to work with teachers’ professional development and learning processes. Educational implications and future research directions are discussed.......This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose...... of the Danish study was to investigate and understand teachers’ classroom experiences using Fenstermacher’s approach to develop a practical argument, as these classroom experiences are regarded as a potential source of learning for teachers. A three-level scale model from the study describes the teach-ers...

  12. Recoil ion spectroscopy with heavy ions

    International Nuclear Information System (INIS)

    Beyer, H.F.; Mann, R.

    1984-01-01

    This chapter examines the production of very high charge state ions in single ion-atom collisions. Topics considered include some aspects of highly ionized atoms, experimental approaches, the production of highly charged target ions (monoatomic targets, recoil energy distribution, molecular fragmentation, outer-shell rearrangement, lifetime measurements, a comparison of projectile-, target-, and plasma-ion stripping), and secondary collision experiments (selective electron capture, potential applications). The heavy-ion beams for the described experiments were provided by accelerators such as tandem Van de Graaff facility and the UNILAC

  13. Pattern formation on Ge by low energy ion beam erosion

    International Nuclear Information System (INIS)

    Teichmann, Marc; Lorbeer, Jan; Frost, Frank; Rauschenbach, Bernd; Ziberi, Bashkim

    2013-01-01

    Modification of nanoscale surface topography is inherent to low-energy ion beam erosion processes and is one of the most important fields of nanotechnology. In this report a comprehensive study of surface smoothing and self-organized pattern formation on Ge(100) by using different noble gases ion beam erosion is presented. The investigations focus on low ion energies (⩽ 2000 eV) and include the entire range of ion incidence angles. It is found that for ions (Ne, Ar) with masses lower than the mass of the Ge target atoms, no pattern formation occurs and surface smoothing is observed for all angles of ion incidence. In contrast, for erosion with higher mass ions (Kr, Xe), ripple formation starts at incidence angles of about 65° depending on ion energy. At smaller incident angles surface smoothing occurs again. Investigations of the surface dynamics for specific ion incidence angles by changing the ion fluence over two orders of magnitude gives a clear evidence for coarsening and faceting of the surface pattern. Both observations indicate that gradient-dependent sputtering and reflection of primary ions play crucial role in the pattern evolution, just at the lowest accessible fluences. The results are discussed in relation to recently proposed redistributive or stress-induced models for pattern formation. In addition, it is argued that a large angular variation of the sputter yield and reflected primary ions can significantly contribute to pattern formation and evolution as nonlinear and non-local processes as supported by simulation of sputtering and ion reflection. (paper)

  14. Surface negative ion production in ion sources

    International Nuclear Information System (INIS)

    Belchenko, Y.

    1993-01-01

    Negative ion sources and the mechanisms for negative ion production are reviewed. Several classes of sources with surface origin of negative ions are examined in detail: surface-plasma sources where ion production occurs on the electrode in contact with the plasma, and ''pure surface'' sources where ion production occurs due to conversion or desorption processes. Negative ion production by backscattering, impact desorption, and electron- and photo-stimulated desorption are discussed. The experimental efficiencies of intense surface negative ion production realized on electrodes contacted with hydrogen-cesium or pure hydrogen gas-discharge plasma are compared. Recent modifications of surface-plasma sources developed for accelerator and fusion applications are reviewed in detail

  15. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 1 covers papers on the advances of gas phase ion chemistry. The book discusses the advances in flow tubes and the measurement of ion-molecule rate coefficients and product distributions; the ion chemistry of the earth's atmosphere; and the classical ion-molecule collision theory. The text also describes statistical methods in reaction dynamics; the state selection by photoion-photoelectron coincidence; and the effects of temperature and pressure in the kinetics of ion-molecule reactions. The energy distribution in the unimolecular decomposition of ions, as well

  16. Surface generation of negative hydrogen ion beams

    International Nuclear Information System (INIS)

    Bommel, P.J.M. van.

    1984-01-01

    This thesis describes investigations on negative hydrogen ion sources at the ampere level. Formation of H - ions occurs when positive hydrogen ions capture two electrons at metal surfaces. The negative ionization probability of hydrogen at metal surfaces increases strongly with decreasing work function of the surface. The converters used in this study are covered with cesium. Usually there are 'surface plasma sources' in which the hydrogen source plasma interacts with a converter. In this thesis the author concentrates upon investigating a new concept that has converters outside the plasma. In this approach a positive hydrogen ion beam is extracted from the plasma and is subsequently reflected from a low work function converter surface. (Auth.)

  17. Effect of reflective practice education on self-reflection, insight, and reflective thinking among experienced nurses: a pilot study.

    Science.gov (United States)

    Asselin, Marilyn E; Fain, James A

    2013-01-01

    A mixed-method study was conducted to determine whether nurses' participation in a reflective practice continuing education program using a structured reflection model makes a difference in nurses' self-reflection, insight, and reflective thinking about clinical practice situations. Findings suggested that use of structured reflection using question cues, written narratives, and peer-facilitated reflection increased nurses' engagement in self-reflection and enhanced reflective thinking in practice. Including reflective practice education in novice orientation and preceptor training may be beneficial.

  18. Laser ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Bykovskij, Yu

    1979-02-01

    The characteristics a laser source of multiply-ionized ions are described with regard to the interaction of laser radiation and matter, ion energy spectrum, angular ion distribution. The amount of multiple-ionization ions is evaluated. Out of laser source applications a laser injector of multiple-ionization ions and nuclei, laser mass spectrometry, laser X-ray microradiography, and a laser neutron generators are described.

  19. Demystifying the reflective clinical journal

    International Nuclear Information System (INIS)

    Milinkovic, Danielle; Field, Nikki

    2005-01-01

    Student learning on clinical placement is a complex issue and cannot be defined solely by just doing things. Reflection during clinical practice is essential if the student is going to learn from the experience. Therefore it is important for educators to include as part of clinical education programs learning strategies that encourage reflection. The reflective clinical journal is an educational tool that is employed by the School of Medical Radiation Sciences at the University of Sydney to encourage reflection of undergraduate radiation therapy students whilst on clinical placement. This discussion paper explores the key concepts of reflection and the reflective clinical journal. Due to the paucity of information about this issue in radiation therapy the literature reviewed is from across all areas of the health sciences

  20. "Ion" B-Dot and Faraday Cup Results Located Inside The Cathode Knob Of The Self Magnetic Pinch (Smp) Diode (A New Diagnostic For Diode Behavior?)

    Energy Technology Data Exchange (ETDEWEB)

    Mazarakis, Michael G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kiefer, Mark L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leckbee, Joshua J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nielsen, Dan S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ziska, Derek [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-08-01

    This paper describes our effort to measure the back-streaming ions emitted from the target x-ray convertor and thus estimate the ion contribution to the A-K gap bipolar current flow. Knowing the ion contribution is quite important in order to calculate the expected x-ray dose and compare it with the actual measurements. Our plans were first to measure the total ion current using B-dot monitors, Rogowski coils, and Faraday cups and then to utilize filtered Faraday cups and time of flight techniques to identify and measure the various ionic species. The kinetic energy (velocities) of the ions should help evaluate the actual voltage applied at the anode-cathode (A-K) gap. LSP simulations found that the most prominent ions are protons and carbon single plus (C+). For an 8-MV A-K voltage, the estimated proton current back-streaming through an 1 cm in diameter hollow cathode tip was on the average 3 kA and the carbon current 0.7 kA. Since only a small fraction of the ions will make it through the cylindrical aperture, the corresponding total currents were calculated to be respectively 25kA for proton and 7 kA for carbon ions, a quite substantial contribution to the total bipolar beam current. Hence, approximately only 10% of the total back-streaming ionic currents could make it through the hollow cathode tip aperture. Unfortunately the diagnostic cables connecting the Faraday cup and the B-dot monitors to the screen room scopes experienced a large amount of charge pick-up that obliterated our effort to directly measure those relatively small currents. However, we succeeded in measuring those currents indirectly with activation techniques [Contribution of the back-streaming ions to the self-magnetic pinch (SMP) diode Current., M. G. Mazarakis, M. G. Mazarakis, M. E. Cuneo, S. D. Fournier, M. D. Johnston, M. L. Kiefer, J. J. Leckbee, D. S. Nielsen, B.V.Oliver, M. E. Sceiford, S. C. Simpson, T. J. Renk, C. L. Ruiz, T. J. Webb, and D. Ziska. Subitted for publication.]. In

  1. Comparison of the bidirectional reflectance distribution function of various surfaces

    International Nuclear Information System (INIS)

    Fernandez, R.; Seasholtz, R.G.; Oberle, L.G.; Kadambi, J.R.

    1989-01-01

    This paper describes the development and use of a system to measure the bidirectional reflectance distribution function (BRDF) of various surfaces. The BRDF measurements are to be used in the analysis and design of optical measurement systems such as laser anemometers. An Ar-ion laser (514 nm) was the light source. Preliminary results are presented for eight samples: two glossy black paints, two flat black paints, black glass, sand-blasted Al, unworked Al, and a white paint. A BaSO4 white reflectance standard was used as the reference sample throughout the tests. 8 refs

  2. Ion Beam Propulsion Study

    Science.gov (United States)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  3. Source of the backstreaming ion beams in the foreshock region

    International Nuclear Information System (INIS)

    Tanaka, M.; Goodrich, C.C.; Winske, D.; Papadopoulos, K.

    1983-01-01

    A new source mechanism is proposed for the 'reflected' ion beams observed in the foreshock region of the earth's bow shock. In our model the beams originate in the magnetosheath downstream of the qausi-perpendicular portion of the shock. The quasi-perpendicular shock transition is characterized by two downstream ion populations including high-energy gyrating ions in addition to the directly transmitted anisotropic ions. We show by particle simulations that this highly anisotropic downstream ion distribution (T/sub perpendicular//T/sub parallel/ >>1) can excite electromagnetic ion cyclotron waves which, in turn, pitch angle scatter the gyrating ions in a few ion gyroperiods. As a result, some ions acquire large parallel velocities and move fast enough along the convecting downstream magnetic field to escape back across the bow shock into the upstream region. The distribution of escaping ions calculated by using the pitch-angle-scattered ions, as a source, becomes a beam with a large temperature anisotropy T/sub perpendicular/ approx.3--5 T/sub parallel/ and a mean velocity along the magnetic field of about twice that of the solar wind velocity. A significant result is the presence of the maximum angle theta/sub n/B = theta/sub c/ above which no ions can escape, where theta/sub n/B is the angle between the shock normal and the interplanetary magnetic field. A wide peak of constant escaping ion flux is formed below theta/sub c/ whose number density is 1--2% of that of the solar wind. These results are in general agreement with the ISEE observations of the 'reflected' ions

  4. Berlin Reflectance Spectral Library (BRSL)

    Science.gov (United States)

    Henckel, D.; Arnold, G.; Kappel, D.; Moroz, L. V.; Markus, K.

    2017-09-01

    The Berlin Reflectance Spectral Library (BRSL) provides a collection of reflectance spectra between 0.3 and 17 µm. It was originally dedicated to support space missions to small solar system bodies. Meanwhile the library includes selections of biconical reflectance spectra for spectral data analysis of other planetary bodies as well. The library provides reference spectra of well-characterized terrestrial analogue materials and meteorites for interpretation of remote sensing reflectance spectra of planetary surfaces. We introduce the BRSL, summarize the data available, and access to use them for further relevant applications.

  5. Students’ Learning through Reflective Journaling

    Directory of Open Access Journals (Sweden)

    Alvyda Liuolienė

    2011-04-01

    Full Text Available The aim of the article is to get acquainted with the types of journals used in education to help students to learn. The paper presents some ways of fostering student’s learning through reflective journaling. It also describes the key aspects of a new method ARRIVE cycle in connection with teachers preparation to use reflective journals in a classroom. The article also presents self-assessment in reflective journaling and students’ need to self-evaluate their learning process. Reflective journaling as central to students’ self-evaluation is described as a means of fostering metacognition.

  6. Studies of the Reflection, Refraction and Internal Reflection of Light

    Science.gov (United States)

    Lanchester, P. C.

    2014-01-01

    An inexpensive apparatus and associated experiments are described for studying the basic laws of reflection and refraction of light at an air-glass interface, and multiple internal reflections within a glass block. In order to motivate students and encourage their active participation, a novel technique is described for determining the refractive…

  7. Cultivating Reflective Practitioners in Technology Preparation: Constructing TPACK through Reflection

    Directory of Open Access Journals (Sweden)

    Liangyue Lu

    2013-12-01

    Full Text Available Teaching is a complex profession, which is further complicated by the integration of technology into classrooms. Reflection can help teachers unpack the complexity in their practice. Reflection can be an effective instructional strategy in helping preservice teachers develop technological pedagogical content knowledge (TPACK, the complex and dynamic knowledge necessary for effective technology integration into instruction. In this study, reflective activities were integrated into a Learning By Design (LBD environment, which was created to help preservice teachers develop TPACK. This paper investigated the participants’ TPACK development and examined how reflection helped them construct TPACK. Through content analysis of the participants’ reflective journals, the researcher found that the preservice teachers developed initial TPACK awareness. However, their reflection in technology knowledge and the content aspects of TPACK were limited and superficial. Interviews with the participants showed reflection helped the preservice teachers remember what they learned by describing and elaborating on their in-class experiences, pushed them to think about how to apply what they learned in their future classrooms, and helped them become more reflective and open-minded about using technology in classrooms. Finally, the researcher discussed this study’s implications for teacher educators and researchers.

  8. Reflection and Reflective Practice Discourses in Coaching: A Critical Analysis

    Science.gov (United States)

    Cushion, Christopher J.

    2018-01-01

    Reflection and reflective practice is seen as an established part of coaching and coach education practice. It has become a "taken-for-granted" part of coaching that is accepted enthusiastically and unquestioningly, and is assumed to be "good" for coaching and coaches. Drawing on sociological concepts, a primarily Foucauldian…

  9. Postgraduate Education to Support Organisation Change: A Reflection on Reflection

    Science.gov (United States)

    Stewart, Jim; Keegan, Anne; Stevens, Pam

    2008-01-01

    Purpose: This paper aims to explore how teaching and assessing reflective learning skills can support postgraduate practitioners studying organisational change and explores the challenges for tutors in assessing these journals. Design/methodology/approach: Assessment criteria were developed from the literature on reflective practice and…

  10. Ion beam induced stress formation and relaxation in germanium

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, T., E-mail: Tobias.Steinbach@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Reupert, A.; Schmidt, E.; Wesch, W. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2013-07-15

    Ion irradiation of crystalline solids leads not only to defect formation and amorphization but also to mechanical stress. In the past, many investigations in various materials were performed focusing on the ion beam induced damage formation but only several experiments were done to investigate the ion beam induced stress evolution. Especially in microelectronic devices, mechanical stress leads to several unwanted effects like cracking and peeling of surface layers as well as changing physical properties and anomalous diffusion of dopants. To study the stress formation and relaxation process in semiconductors, crystalline and amorphous germanium samples were irradiated with 3 MeV iodine ions at different ion fluence rates. The irradiation induced stress evolution was measured in situ with a laser reflection technique as a function of ion fluence, whereas the damage formation was investigated by means of Rutherford backscattering spectrometry. The investigations show that mechanical stress builds up at low ion fluences as a direct consequence of ion beam induced point defect formation. However, further ion irradiation causes a stress relaxation which is attributed to the accumulation of point defects and therefore the creation of amorphous regions. A constant stress state is reached at high ion fluences if a homogeneous amorphous surface layer was formed and no further ion beam induced phase transition took place. Based on the results, we can conclude that the ion beam induced stress evolution seems to be mainly dominated by the creation and accumulation of irradiation induced structural modification.

  11. The Heavy Ion Sensor (HIS) Onboard Solar Orbiter (SOLO): Calibration Results and Science Outlook

    Science.gov (United States)

    Livi, S. A.; Lepri, S. T.; Raines, J. M.; Galvin, A.; Kistler, L. M.; Allegrini, F.; Ogasawara, K.; Collier, M. R.

    2017-12-01

    The HIS sensor has been designed and optimized to study heavy ions in the solar wind, suprathermal particles, and pickup ions in the range 0.5 to 75keV/e. This instrument will allow for unprecedented data collection of particle characteristics near the Sun at various heliolatitudes during both the quiet and active phases of the solar cycle. The close proximity and the quasi-corotation will allow for determination of the source regions on the sun for the observed events. As a result of the measurements HIS will take, we will be able to: link events on the surface of the Sun with structures in the interplanetary medium; determine the extent of gravitational settling in the expansion region of the solar wind; identify interplanetary shocks and characterize their spatial and temporal evolution; characterize the power spectra of density and velocity uctuations upstream and downstream of shocks; study the heating and dissipation mechanisms at shocks at various radial distances and latitudes; and identify the mechanisms that heat thermal solar wind ions near shocks and determine the energy partition at shocks. During the course of 2016 and 2017 HIS has been calibrated at the facility of SwRI and University of Bern, using a large energy range (0.1-450 keV), multiple masses (H-Fe), as well as charge states (1-6). The results show that HIS will meet or exceed all necessary requirements to fullfill its ambitious scientific goals.

  12. Ubuntu feminism: Tentative reflections

    Directory of Open Access Journals (Sweden)

    Drucilla Cornell

    2015-06-01

    Full Text Available The starting-point for the article is to provide a brief background on the Ubuntu Project that Prof. Drucilla Cornell convened in 2003; most notably the interviews conducted in Khayamandi, the support of a sewing collective, and the continued search to launch an Ubuntu Women�s Centre. The article will reflect on some of the philosophical underpinnings of ubuntu, whereafter debates in Western feminism will be revisited. Ubuntu feminism is suggested as a possible response to these types of feminisms. The authors support an understanding of ubuntu as critique and ubuntu feminism accordingly as a critical intervention that recalls a politics of refusal. The article ends by raising the importance of thinking about spatiality through ubuntu, and vice versa. It may seem strange to title an article Ubuntu feminism when feminism itself has often been identified as a European or Western idea. But, this article will argue that ubuntu offers conceptions of transindividuality and ways of social belonging that could respond in a meaningful way to some of European feminism�s own dilemmas and contradictions. Famously, one of the most intense debates in feminism was between those who defended an ethic of care in a relational view of the self, on one side, and those feminists who held on to more traditional conceptions of justice, placing an emphasis on individuality and autonomy, on the other side. The authors will suggest that ubuntu could address this tension in feminism. Thus, in this article the focus will not simply be on ubuntu, in order to recognise that there are other intellectual heritages worthy of consideration, other than those in Europe and the United States. It will also take a next step in arguing that ubuntu may be a better standpoint entirely from which to continue thinking about what it means to be a human being, as well as how to conceive of the integral interconnection human beings all have with one another. This connection through

  13. Ion sources for heavy ion fusion

    International Nuclear Information System (INIS)

    Yu, S.S.; Eylon, S.; Chupp, W.

    1995-09-01

    The development of ion sources for heavy ion fusion will be reported with particular emphasis on a recently built 2 MV injector. The new injector is based on an electrostatic quadrupole configuration, and has produced pulsed K + ions of 950 mA peak from a 6.7 inch curved alumino silicate source. The ion beam has reached 2.3 MV with an energy flatness of ±0.2% over 1 micros. The measured normalized edge emittance of less than 1 π mm-mr is close to the source temperature limit. The design, construction, performance, and comparisons with three-dimensional particle-in-cell simulations will be described

  14. Electromagnetic ion beam instability upstream of the earth's bow shock

    International Nuclear Information System (INIS)

    Gary, S.P.; Gosling, J.T.; Forslund, D.W.

    1981-01-01

    The linear theory of the electromagnetic ion beam instability for arbitrary angles of propagation has been studied. The parameters considered in the theory are typical of the solar wind upstream of the earth's bow shock when a 'reflected' proton beam is present. Maximum growth occurs for propagation parallel to the ambient field B, but this instability also displays significant growth at wave-vectors oblique to B, Oblique, unstable modes seem to be the likely source of the compressive magnetic fluctuations recently observed in conjunction with 'diffuse' ion population. An energetic ion beam does not directly give rise to linear growth of either ion acoustic or whistler mode instabilities

  15. Compton profiles by inelastic ion-electron scattering

    International Nuclear Information System (INIS)

    Boeckl, H.; Bell, F.

    1983-01-01

    It is shown that Compton profiles (CP) can be measured by inelastic ion-electron scattering. Within the impulse approximation the binary-encounter peak (BEP) reflects the CP of the target atom whereas the electron-loss peak (ELP) is given by projectile CP's. Evaluation of experimental data reveals that inelastic ion-electron scattering might be a promising method to supply inelastic electron or photon scattering for the determination of target CP's. The measurement of projectile CP's is unique to ion scattering since one gains knowledge about wave-function effects because of the high excitation degree of fast heavy-ion projectiles

  16. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  17. Ethical Reflections on Becoming Teachers

    Science.gov (United States)

    Joseph, Pamela Bolotin

    2016-01-01

    This study analyzes narratives written in a culminating graduate seminar on reflective practice by 36 new secondary teachers who were asked to consider their moral beliefs, moral values and system of ethics as they reflected on their recent student teaching experiences. The findings explore how the participants depicted their constructed moral…

  18. Flexible Bistable Cholesteric Reflective Displays

    Science.gov (United States)

    Yang, Deng-Ke

    2006-03-01

    Cholesteric liquid crystals (ChLCs) exhibit two stable states at zero field condition-the reflecting planar state and the nonreflecting focal conic state. ChLCs are an excellent candidate for inexpensive and rugged electronic books and papers. This paper will review the display cell structure,materials and drive schemes for flexible bistable cholesteric (Ch) reflective displays.

  19. Neutron reflectivity of electrodeposited thin magnetic films

    International Nuclear Information System (INIS)

    Cooper, Joshaniel F.K.; Vyas, Kunal N.; Steinke, Nina-J.; Love, David M.; Kinane, Christian J.; Barnes, Crispin H.W.

    2014-01-01

    Highlights: • Electrodeposited magnetic bi-layers were measured by polarised neutron reflectivity. • When growing a CoNiCu alloy from a single bath a Cu rich region is initially formed. • This Cu rich region is formed in the first layer but not subsequent ones. • Ni deposition is inhibited in thin film growth and Co deposits anomalously. • Alloy magnetism and neutron scattering length give a self-consistent model. - Abstract: We present a polarised neutron reflectivity (PNR) study of magnetic/non-magnetic (CoNiCu/Cu) thin films grown by single bath electrodeposition. We find that the composition is neither homogeneous with time, nor consistent with bulk values. Instead an initial, non-magnetic copper rich layer is formed, around 2 nm thick. This layer is formed by the deposition of the dilute, but rapidly diffusing, Cu 2+ ions near the electrode surface at the start of growth, before the region is depleted and the deposition becomes mass transport limited. After the region has been depleted, by growth etc., this layer does not form and thus may be prevented by growing a copper buffer layer immediately preceding the magnetic layer growth. As has been previously found, cobalt deposits anomalously compared to nickel, and even inhibits Ni deposition in thin films. The layer magnetisation and average neutron scattering length are fitted independently but both depend upon the alloy composition. Thus these parameters can be used to check for model self-consistency, increasing confidence in the derived composition

  20. Reflection measurements for luminescent powders

    Science.gov (United States)

    Kroon, R. E.

    2018-04-01

    Luminescent materials are useful in applications varying from lighting and display technologies to document security features and medical research, amongst many others. Measurement of the excitation range is an important consideration, and absorption bands are often determined from a decrease in the measured diffuse reflectance of the material using a ultraviolet-visible (UV-vis) spectrophotometer with an integrating sphere. Such a system may provide questionable results when used to measure the reflectance of a luminescence material, which is demonstrated for a Tb doped silica phosphor, because the system cannot differentiate between the reflected light and luminescence. It is shown that more reliable results are achieved for this phosphor by measuring the reflectance using a synchronous zero-offset scan in a fluorescence spectrometer equipped with an integrating sphere. This method is therefore recommended instead of traditional reflectance measurements using a UV-vis spectrophotometer for luminescent powders.

  1. Ions and light

    CERN Document Server

    Bowers, Michael T

    2013-01-01

    Gas Phase Ion Chemistry, Volume 3: Ions and Light discusses how ions are formed by electron impact, ion-molecule reactions, or electrical discharge. This book discusses the use of light emitted by excited molecules to characterize either the chemistry that formed the excited ion, the structure of the excited ion, or both.Organized into 10 chapters, this volume begins with an overview of the extension of the classical flowing afterglow technique to include infrared and chemiluminescence and laser-induced fluorescence detection. This text then examines the experiments involving molecules that ar

  2. Níveis de ruído emitidos por uma recolhedora-trilhadora de feijão Evaluation of noise levels emitted by a bean pick-up machine

    Directory of Open Access Journals (Sweden)

    Luiz H. Souza

    2004-12-01

    Full Text Available Foram avaliados os níveis de ruído emitido por uma recolhedora-trilhadora de feijão. Empregou-se o delineamento experimental em blocos casualizados, com quatro repetições e esquema de parcelas subdivididas. Utilizaram-se três declividades do terreno (0 a 10; 10 a 20 e 20 a 30% e três velocidades de operação (2,0; 2,5 e 3,0 km h-1 para compor as parcelas e subparcelas, respectivamente. Os dados foram interpretados pela análise de variância (teste F e as médias comparadas pelo teste de Tukey, a 5% de probabilidade. Os níveis de ruído determinados ultrapassaram o limite de 85 dBA para oito horas de exposição diária estabelecido pela NR-15. Ocorreu aumento do nível de ruído com o incremento da declividade e com a diminuição da velocidade de trabalho.The noise levels of a bean pick-up machine were evaluated. The experimental procedure consisted of randomized blocks, with four repetitions, with subdivided plots. The plots were composed by the declivity of 0-10; 10-20 and 20-30%. The Bean Pickup Machine velocities were 2.0; 2.5 and 3.0 km h-1. The data were interpreted by the variation analyze. The averages were compared using the Tukey test at 5% of probability. The noise levels were superior to the 85 dBA limit for eight hours of daily exposure. This is established by the NR-15 (Brasilian Legislation on Insalubrity. There was an increase in the noise levels with the declivity increment and with velocity decrease.

  3. Nonlinear MHD waves and discontinuities in the Martian magnetosheath. Observations and 2D bi-ion MHD simulations

    Science.gov (United States)

    Sauer, K.; Dubinin, E.; Baumgärtel, K.

    1998-09-01

    The characteristic scale of the Martian magnetosheath is less than the pick-up gyroradius of oxygen ions. This leads to admissible differential motion of protons and heavies and a strong coupling between both ion fluids. 2D bi-ion MHD simulations reveal many new interesting features in such Large Larmour Radius systems. The formation of an ion-composition boundary, which separates both plasmas, and structuring of the transition from proton dominated plasma of the solar wind origin to massive planetary plasma are the main features of the interaction. A comprehensive multi-instrument study of Martian plasma environment and the comparison with theoretical modelling initiated in the framework of the Visiting Science Programme of the International Space Science Institute (ISSI) in Bern (Switzerland) gives confirmation that Mars interacts with the solar wind like a comet which has a outgassing rate near to that of Grigg-Skjellerup. The results may also be relevant for small bodies which are surrounded by a neutral gas atmosphere (icy moons, asteroids, Mercury).

  4. Negative-ion states

    International Nuclear Information System (INIS)

    Compton, R.N.

    1982-01-01

    In this brief review, we discuss some of the properties of atomic and molecular negative ions and their excited states. Experiments involving photon reactions with negative ions and polar dissociation are summarized. 116 references, 14 figures

  5. Quadrupole Ion Traps

    Indian Academy of Sciences (India)

    to do precision spectroscopic measurements on these ions. ... Bonn, investigated the non-magnetic quadrupole mass filter, .... the details of which will be discussed in the subse- ... the radial plane the ion undergoes a circular motion with the.

  6. Negative ion detachment processes

    International Nuclear Information System (INIS)

    Champion, R.L.; Doverspike, L.D.

    1990-10-01

    This paper discusses the following topics: H - and D - collisions with atomic hydrogen; collisional decomposition of SF 6 - ; two-electron loss processes in negative ion collisions; associative electron detachment; and negative ion desorption from surfaces

  7. Ion sources in AMS

    International Nuclear Information System (INIS)

    Iyer, Indira S.

    1997-01-01

    Accelerator Mass Spectrometry (AMS) entails the sputtering of various samples in an ion source followed by high precision mass analysis of the sputtered ion species in a Tandem Electrostatic Accelerator. A brief account is given

  8. Single Cathode Ion Thruster

    Data.gov (United States)

    National Aeronautics and Space Administration — Objective is to design an electrostatic ion thruster that is more efficient, simpler, and lower cost than the current gridded ion thruster. Initial objective is to...

  9. Applications of decelerated ions

    International Nuclear Information System (INIS)

    Johnson, B.M.

    1985-03-01

    Many facilities whose sole purpose had been to accelerate ion beams are now becoming decelerators as well. The development and current status of accel-decel operations is reviewed here. Applications of decelerated ions in atomic physics experiments are discussed

  10. Fundamentals of ion exchange

    International Nuclear Information System (INIS)

    Townsend, R.P.

    1993-01-01

    In this paper the fundamentals of ion exchange mechanisms and their thermodynamics are described. A range of ion exchange materials is considered and problems of communication and technology transfer between scientists working in the field are discussed. (UK)

  11. Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold.

    Science.gov (United States)

    Petoral, Rodrigo M; Björefors, Fredrik; Uvdal, Kajsa

    2006-11-23

    Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

  12. Resonating rays in ion-ion scattering from an optical potential

    International Nuclear Information System (INIS)

    Farhan, A.R.; Stoyanov, B.J.; Nagl, A.; Uberall, H.; de Llano, M.

    1986-01-01

    The amplitude of ion-ion scattering, described, e.g., by an optical potential, separates into a ''surface-wave'' part (which, as shown before, may give rise to resonances) and a ''geometrical-ray'' part. The amplitude as alternately expressed here by the Wentzel-Kramers-Brillouin approximation resolves into an externally reflected ''barrier wave'' and into ''internal'' or ''penetrating rays'' that undergo an internal reflection together with possible additional multiple reflections. Our numerical calculations show that resonances also occur in the penetrating rays, which take place when a characteristic equation is satisfied. The geometrical meaning of the latter is determined by the optical path length of penetration being an integer multiple of π, plus a 1/2π caustic phase jump, and an extra phase shift due to barrier penetration

  13. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  14. Ion mobility spectrometry

    CERN Document Server

    Eiceman, GA

    2005-01-01

    Key Developments for Faster, More Precise Detection Capabilities Driven by the demand for the rapid and advanced detection of explosives, chemical and biological warfare agents, and narcotics, ion mobility spectrometry (IMS) undergone significant refinements in technology, computational capabilities, and understanding of the principles of gas phase ion chemistry and mobility. Beginning with a thorough discussion of the fundamental theories and physics of ion mobility, Ion Mobility Spectrometry, Second Edition describes the recent advances in instrumentation and newly

  15. Intense ion beam generator

    International Nuclear Information System (INIS)

    Humphries, S. Jr.; Sudan, R.N.

    1977-01-01

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation

  16. Effect of nuclear track on reflectivity for insulating material

    International Nuclear Information System (INIS)

    Liu Cunxiong; Ni Bangfa; Tian Weizhi; Hu Lian; Xiao Caijin; Wang Pingsheng; Zhang Guiying; Huang Donghui; Lu Peng; Yang Weitao

    2009-01-01

    Polyester and CR-39 samples were irradiated with sulphur ion from HI-13 tandem accelerator. Ultraviolet light with wavelength 360 nm was used to sensitize the polymer before chemical etching by NaOH solution with different temperatures and time duration. The latent track was then developed into nanometer to micrometer pore with certain depth. Samples were coated with thin layer of silver and magnesium fluoride using the vacuum evaporator. The reflectivity and transmission index were measured for all polymer samples, untreated and treated with above-mentioned procedure, within the wavelength of visible light. Solid state nuclear track and coating can reduce reflectivity of tested polymer materials greatly, and the reflectivity can be 1% or lower. (authors)

  17. Ion sources for accelerators

    International Nuclear Information System (INIS)

    Alton, G.D.

    1974-01-01

    A limited review of low charge sate positive and negative ion sources suitable for accelerator use is given. A brief discussion is also given of the concepts underlying the formation and extraction of ion beams. Particular emphasis is placed on the technology of ion sources which use solid elemental or molecular compounds to produce vapor for the ionization process

  18. Negative Ion Density Fronts

    International Nuclear Information System (INIS)

    Igor Kaganovich

    2000-01-01

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas

  19. Nanostructures by ion beams

    Science.gov (United States)

    Schmidt, B.

    Ion beam techniques, including conventional broad beam ion implantation, ion beam synthesis and ion irradiation of thin layers, as well as local ion implantation with fine-focused ion beams have been applied in different fields of micro- and nanotechnology. The ion beam synthesis of nanoparticles in high-dose ion-implanted solids is explained as phase separation of nanostructures from a super-saturated solid state through precipitation and Ostwald ripening during subsequent thermal treatment of the ion-implanted samples. A special topic will be addressed to self-organization processes of nanoparticles during ion irradiation of flat and curved solid-state interfaces. As an example of silicon nanocrystal application, the fabrication of silicon nanocrystal non-volatile memories will be described. Finally, the fabrication possibilities of nanostructures, such as nanowires and chains of nanoparticles (e.g. CoSi2), by ion beam synthesis using a focused Co+ ion beam will be demonstrated and possible applications will be mentioned.

  20. Reflection measurements of microwave absorbers

    Science.gov (United States)

    Baker, Dirk E.; van der Neut, Cornelis A.

    1988-12-01

    A swept-frequency interferometer is described for making rapid, real-time assessments of localized inhomogeneities in planar microwave absorber panels. An aperture-matched exponential horn is used to reduce residual reflections in the system to about -37 dB. This residual reflection is adequate for making comparative measurements on planar absorber panels whose reflectivities usually fall in the -15 to -25 dB range. Reflectivity measurements on a variety of planar absorber panels show that multilayer Jaumann absorbers have the greatest inhomogeneity, while honeycomb absorbers generally have excellent homogeneity within a sheet and from sheet to sheet. The test setup is also used to measure the center frequencies of resonant absorbers. With directional couplers and aperture-matched exponential horns, the technique can be easily applied in the standard 2 to 40 GHz waveguide bands.

  1. Ibuanyidanda (Complementary Reflection), Communalism and ...

    African Journals Online (AJOL)

    Fr. Prof. Asouzu

    Glossary of Igbo Terms and Phrases ihe ahụ na anya ... other words, it is in mutual dependence that the feeling of intimacy found among kindred ..... Complementary Reflection, Communalism and Theory Formulation in African Philosophy 25.

  2. Worldwide Marine Seismic Reflection Profiles

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC maintains a large volume of both Analog and Digital seismic reflection data. Currently only a limited number of lines are available online. Digital data include...

  3. Reflective Methodology: The Beginning Teacher

    Science.gov (United States)

    Templeton, Ronald K.; Siefert, Thomas E.

    1970-01-01

    Offers a variety of specific techniques which will help the beginning teacher to implement reflective methodology and create an inquiry-centered classroom atmosphere, at the same time meeting the many more pressing demands of first-year teaching. (JES)

  4. High-resolution reflection spectroscopy

    International Nuclear Information System (INIS)

    Ducloy, Martial

    1997-01-01

    In this article some recent developments in selective reflection spectroscopy is reviewed and the various ways to extend Doppler free techniques to this spectroscopic field is discussed. Its main feature is to probe atomic gas close to the cell boundaries

  5. Enhanced ion acoustic fluctuations and ion outflows

    Directory of Open Access Journals (Sweden)

    F. R. E. Forme

    1999-02-01

    Full Text Available A number of observations showing enhanced ion acoustic echoes observed by means of incoherent scatter radars have been reported in the literature. The received power is extremely enhanced by up to 1 or 2 orders of magnitude above usual values, and it is mostly contained in one of the two ion acoustic lines. This spectral asymmetry and the intensity of the received signal cannot be resolved by the standard analysis procedure and often causes its failure. As a result, and in spite of a very clear spectral signature, the analysis is unable to fit the plasma parameters inside the regions of ion acoustic turbulence. We present European Incoherent Scatter radar (EISCAT observations of large ion outflows associated with the simultaneous occurrence of enhanced ion acoustic echoes. The ion fluxes can reach 1014 m-2 s-1 at 800 km altitude. From the very clear spectral signatures of these echoes, a method is presented to extract estimates of the electron temperature and the ion drift within the turbulent regions. It is shown that the electron gas is strongly heated up to 11 000 K. Also electron temperature gradients of about 0.02 K/m exist. Finally, the estimates of the electron temperature and of the ion drift are used to study the possible implications for the plasma transport inside turbulent regions. It is shown that strong electron temperature gradients cause enhancement of the ambipolar electric field and can account for the observed ion outflows.Key words. Ionosphere (auroral ionosphere; ionosphere · magnetosphere interactions; plasma waves and instabilities.

  6. Data sets for hydrogen reflection and their use in neutral transport calculations

    International Nuclear Information System (INIS)

    Eckstein, W.; Heifetz, D.B.

    1986-08-01

    A realistic characterization of the interaction of ions and neutral particles with device walls is important for any edge plasma calculation. Present reflection models vary in detail and computational efficiency. This paper presents a data set for the distribution of the reflection coefficient, R N , over reflected energy, polar, and azimuthal angles, as functions of incident polar angle and energy. These results have been computed using a vectorized version of the TRIM Monte Carlo code. The data are stored using an algorithm for reducing the data into three one-dimensional distributions, resulting in a realistic reflection model which can be used very efficiently in plasma edge calculations. (orig.)

  7. Analytic Reflected Lightcurves for Exoplanets

    Science.gov (United States)

    Haggard, Hal M.; Cowan, Nicolas B.

    2018-04-01

    The disk-integrated reflected brightness of an exoplanet changes as a function of time due to orbital and rotational motion coupled with an inhomogeneous albedo map. We have previously derived analytic reflected lightcurves for spherical harmonic albedo maps in the special case of a synchronously-rotating planet on an edge-on orbit (Cowan, Fuentes & Haggard 2013). In this letter, we present analytic reflected lightcurves for the general case of a planet on an inclined orbit, with arbitrary spin period and non-zero obliquity. We do so for two different albedo basis maps: bright points (δ-maps), and spherical harmonics (Y_l^m-maps). In particular, we use Wigner D-matrices to express an harmonic lightcurve for an arbitrary viewing geometry as a non-linear combination of harmonic lightcurves for the simpler edge-on, synchronously rotating geometry. These solutions will enable future exploration of the degeneracies and information content of reflected lightcurves, as well as fast calculation of lightcurves for mapping exoplanets based on time-resolved photometry. To these ends we make available Exoplanet Analytic Reflected Lightcurves (EARL), a simple open-source code that allows rapid computation of reflected lightcurves.

  8. Understanding the anisotropic ion distributions within magnetotail dipolarizing flux bundles

    Science.gov (United States)

    Zhou, X.; Runov, A.; Angelopoulos, V.; Birn, J.

    2017-12-01

    Dipolarizing flux bundles (DFBs), earthward-propagating structures with enhanced northward magnetic field (Bz) component, are usually believed to carry a different plasma population from that in the ambient magnetotail plasma sheet. The ion distribution functions within the DFB, however, are recently found to be largely controlled by the ion adiabaticity parameter κ in the ambient plasma sheet outside the DFBs. According to these observations, the ambient κ values of 2-3 usually correspond to a strong perpendicular anisotropy of suprathermal ions within the DFBs, whereas for lower κ values the ions inside the DFBs become more isotropic. Here we utilize a simple, test-particle model to explore the nature of the anisotropy and its dependence on the ambient κ values. We find that the ion anisotropy originates from successive ion reflections and reentries to the DFBs, during which the ions can be consecutively accelerated in the perpendicular direction by the DFB-carried electric field. This acceleration process may be interrupted, however, when the magnetic field lines are highly curved in the ambient plasma sheet. In this case, the ion trajectories are most stochastic outside the DFB region, which makes the reflected ions less likely to return to the DFBs for another cycle of acceleration; as a consequence, the perpendicular ion anisotropy does not appear. Given that the DFB ions are a free energy source for instabilities when they are injected towards Earth, our simple model (that reproduces most observational features on the anisotropic DFB ion distributions) may shed new lights on the coupling process between the magnetotail and the inner magneosphere.

  9. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.

    2013-12-16

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  10. ION INJECTION AT QUASI-PARALLEL SHOCKS SEEN BY THE CLUSTER SPACECRAFT

    International Nuclear Information System (INIS)

    Johlander, A.; Vaivads, A.; Khotyaintsev, Yu. V.; Retinò, A.; Dandouras, I.

    2016-01-01

    Collisionless shocks in space plasma are known to be capable of accelerating ions to very high energies through diffusive shock acceleration (DSA). This process requires an injection of suprathermal ions, but the mechanisms producing such a suprathermal ion seed population are still not fully understood. We study acceleration of solar wind ions resulting from reflection off short large-amplitude magnetic structures (SLAMSs) in the quasi-parallel bow shock of Earth using in situ data from the four Cluster spacecraft. Nearly specularly reflected solar wind ions are observed just upstream of a SLAMS. The reflected ions are undergoing shock drift acceleration (SDA) and obtain energies higher than the solar wind energy upstream of the SLAMS. Our test particle simulations show that solar wind ions with lower energy are more likely to be reflected off the SLAMS, while high-energy ions pass through the SLAMS, which is consistent with the observations. The process of SDA at SLAMSs can provide an effective way of accelerating solar wind ions to suprathermal energies. Therefore, this could be a mechanism of ion injection into DSA in astrophysical plasmas

  11. Heavy-ion radiography

    International Nuclear Information System (INIS)

    Fabrikant, J.I.; Tobias, C.A.; Holley, W.R.; Benton, E.V.; Woodruff, K.H.; MacFarland, E.W.

    1983-01-01

    High energy, heavy-ion beams offer superior discrimination of tissue electron densities at very low radiation doses. This characteristic has potential for diagnostic medical imaging of neoplasms arising in the soft tissues and organs because it can detect smaller inhomogeneities than x rays. Heavy-ion imaging may also increase the accuracy of cancer radiotherapy planning involving use of accelerated charged particles. In the current physics research program of passive heavy-ion imaging, critical modulation transfer function tests are being carried out in heavy-ion projection radiography and heavy-ion computerized tomography. The research goal is to improve the heavy-ion imaging method until it reaches the limits of its theoretical resolution defined by range straggling, multiple scattering, and other factors involved in the beam quality characteristics. Clinical uses of the imaging method include the application of heavy-ion computerized tomography to heavy-ion radiotherapy planning, to the study of brain tumors and other structures of the head, and to low-dose heavy-ion projection mammography, particularly for women with dense breasts where other methods of diagnosis fail. The ions used are primarily 300 to 570 MeV/amu carbon and neon ions accelerated at the Lawrence Berkeley Laboratory Bevalac

  12. Ion implantation into iron

    International Nuclear Information System (INIS)

    Iwaki, Masaya

    1978-01-01

    The distribution of implanted ions in iron, the friction characteristics and the corrosion of iron were studied. The distribution of Ni or Cr ions implanted into mild steel was measured. The accelerated voltage was 150 keV, and the beam current density was about 2 microampere/cm 2 . The measurement was made with an ion microanalyzer. The measured distribution was compared with that of LSS theory. Deep invasion of Ni was seen in the measured distribution. The distribution of Cr ions was different from the distribution calculated by the LSS theory. The relative friction coefficient of mild steel varied according to the dose of implanted Cu or N ions, and to the accelerating voltage. Formation of compound metals on the surfaces of metals by ion-implantation was investigated for the purpose to prevent the corrosion of metals. The resistance of mild steel in which Ni ions were implanted was larger than that of mild steel without any treatment. (Kato, T.)

  13. Crater formation by single ions, cluster ions and ion "showers"

    CERN Document Server

    Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter

    2011-01-01

    The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...

  14. Optical effects of ion implantation

    International Nuclear Information System (INIS)

    Townsend, P.D.

    1987-01-01

    The review concerns the effects of ion implantation that specifically relate to the optical properties of insulators. Topics which are reviewed include: ion implantation, ion range and damage distributions, colour centre production by ion implantation, high dose ion implantation, and applications for integrated optics. Numerous examples are presented of both diagnostic and industrial examples of ion implantation effects in insulators. (U.K.)

  15. Analytic descriptions of ion cyclotron absorption

    International Nuclear Information System (INIS)

    Bers, A.; Francis, G.; Fuchs, V.; Lashmore-Davies, C.N.; Ram, A.K.

    1987-05-01

    Analysis of energy propagation and absorption in ion-cyclotron heating of tokamak plasmas has relied on numerical solutions of fourth (and sixth) order differential equations for slab models of the plasma (poloidal) cross section. Realistic two-dimensional and fully toroidal geometry analyses would become quite unwieldy. It is shown here that the analysis of the slab model can be simplified considerably. A first-order differential equation is shown to describe the transmission coefficient for the fast wave, and it is solved analytically. A second order differential equation is shown to adequately describe both transmission and reflection. Conditions for ion absorption or mode conversion are derived. Including toroidal effects in propagation, conditions for electron absorption on the mode-converted ion-Bernstein waves are also described analytically

  16. Reflections

    Indian Academy of Sciences (India)

    physics, and to whom he always remained close - his sister Maja. .... moved to Munich at the beginning of 1882, when Albert was barely two years old. ... This was demonstrated during a further change in the sphere of activity of .... As is well known, in Germany one uses the polite form "Sie" for adults and for people who.

  17. Reflections

    Indian Academy of Sciences (India)

    2004-04-01

    Apr 1, 2004 ... journal Current Science, Vol 61, 1991, pp.594-600. It is an ... could be explained as mere imperfections in the fossil record. .... would almost seem that exposure to the rigours of the climate had quickened the pace ... would be interesting to know whether this telescoping effect is the outward manifesta-.

  18. Reflections

    Indian Academy of Sciences (India)

    making computer programs 'human like' by building in learning and ... discussed the problems of control and communication in the living organism and the machine. ... To be effective in warding off disastrous consequences, our understanding.

  19. Reflections

    Indian Academy of Sciences (India)

    not only in linguistics hut also in allied fields, splitting social scientists into t\\VO groups, Chomskyan and others. ... views on language, IlO\\\\"knoVv'Il as 'Standard Theory', generated a ... For the human mind, learning is a kind of reminiscence.

  20. Reflections

    Indian Academy of Sciences (India)

    future seemed secure, and there was such complete harmony of character between ... was at once so taken with the idea that he was able to persuade Hermann Einstein to .... A liberal spirit, undogmatic in matters of religion, brought by both.