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Sample records for atomic beam source

  1. Atomic oxygen beam source for erosion simulation

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    A device for production of low-energy (5-10 eV) neutral atomic beams for surface modification studies, which recreates the flux of atomic oxygen in LEO, is described. The beam is produced by acceleration of plasma ions onto a negatively biased plate of high-Z metal; the ions are neutralized and reflected by the surface, retaining a large fraction of their incident kinetic energy, forming a beam of atoms. The device is based on a magnetically confined (3-4 kG) coaxial plasma source and the atom energy can be varied by adjusting the bias voltage. The source provides a neutral flux of roughly 5 x 10 to the 16th/sq cm/s at a distance of 10 cm and a fluence of roughly 10 to the 21st/sq cm in five hours. The source has been characterized with plasma diagnostics and by measuring the energy of an atomic argon beam using a mass spectrometer. Samples of carbon film, carbon-based paint, Kapton, Mylar, and Teflon exposed to atomic O beams show erosion quite similar to those observed in orbit on the Space Shuttle.

  2. A new atomic beam source: The ''candlestick''

    NASA Astrophysics Data System (ADS)

    Hau, Lene Vestergaard; Golovchenko, J. A.; Burns, Michael M.

    1994-12-01

    The design of a novel-type of atomic beam source which provides for long term, stable operation at high emission rates is reported. The heart of the design is the ``candlestick'' where liquid source material is transported by capillary action to a localized hot emission region. A surrounding cavity kept at the melting point for the source material shields the vacuum chamber walls from this region. The atomic beam escaping from the source is collimated, and uncollimated atoms are transported back to the liquid reservoir at the bottom of the ``candlestick'' by capillary action. This design has advantages over traditional oven designs: localized heating provides for large emission rates under high vacuum conditions, collimation is combined with recycling and conservation of source material, and the use of capillarity allows any orientation of the beam source. The source has been tested with sodium, and we believe that the design is useful for a broad range of applications including thin-film evaporation, molecular beam epitaxy, and semiconductor surface doping. With the low thermal mass of the emission section, the source could be optimized for pulsed mode operation. Furthermore, it is anticipated that the design ideas presented here could form the basis for a supersonic source with very high Mach numbers.

  3. Atomic oxygen beam source for erosion simulation

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    A device for the production of low energy (3 to 10 eV) neutral atomic beams for surface modification studies is described that reproduces the flux of atomic oxygen in low Earth orbit. The beam is produced by the acceleration of plasma ions onto a negatively biased plate of high-Z metal; the ions are neutralized and reflected by the surface, retaining some fraction of their incident kinetic energy, forming a beam of atoms. The plasma is generated by a coaxial RF exciter which produces a magnetically-confined (4 kG) plasma column. At the end of the column, ions fall through the sheath to the plate, whose bias relative to the plasma can be varied to adjust the beam energy. The source provides a neutral flux approximately equal to 5 x 10(exp 16)/sq cm at a distance of 9 cm and a fluence approximately equal to 10(exp 20)/sq cm in five hours. The composition and energy of inert gas beams was diagnosed using a mass spectometer/energy analyzer. The energy spectra of the beams demonstrate energies in the range 5 to 15 eV, and qualitatively show expected dependences upon incident and reflecting atom species and potential drop. Samples of carbon film, carbon-based paint, Kapton, mylar, and teflon exposed to atomic O beams show erosion quite similar to that observed in orbit on the space shuttle.

  4. Studies on Beam Formation in an Atomic Beam Source

    SciTech Connect

    Nass, A.; Steffens, E.; Stancari, M.

    2009-08-04

    Atomic beam sources (ABS) are widely used workhorses producing polarized atomic beams for polarized gas targets and polarized ion sources. Although they have been used for decades the understanding of the beam formation processes is crude. Models were used more or less successfully to describe the measured intensity and beam parameters. ABS's are also foreseen for future experiments, such as PAX [1]. An increase of intensity at a high polarization would be beneficial. A direct simulation Monte-Carlo method (DSMC)[2] was used to describe the beam formation of a hydrogen or deuterium beam in an ABS. For the first time a simulation of a supersonic gas expansion on a molecular level for this application was performed. Beam profile and Time-of-Flight measurements confirmed the simulation results. Furthermore a new method of beam formation was tested, the Carrier Jet method [3], based on an expanded beam surrounded by an over-expanded carrier jet.

  5. Method for producing uranium atomic beam source

    DOEpatents

    Krikorian, Oscar H.

    1976-06-15

    A method for producing a beam of neutral uranium atoms is obtained by vaporizing uranium from a compound UM.sub.x heated to produce U vapor from an M boat or from some other suitable refractory container such as a tungsten boat, where M is a metal whose vapor pressure is negligible compared to that of uranium at the vaporization temperature. The compound, for example, may be the uranium-rhenium compound, URe.sub.2. An evaporation rate in excess of about 10 times that of conventional uranium beam sources is produced.

  6. The HERMES Polarized Atomic Beam Source

    SciTech Connect

    Nass, A.

    2003-07-30

    The atomic beam source (ABS) provides nuclear polarized hydrogen or deuterium atoms for the HERMES target at flow rates of about 6.5 {center_dot} 1016H-vector/s (hydrogen in two hyperfine substates) and 6.0 {center_dot} 1016D-vector/s (deuterium in three hyperfine substates). The degree of dissociation of 93% for H (95% for D) at the entrance of the storage cell and the nuclear polarization of around 0.97 (H) and 0.92 (D) have been found to be constant within a a couple of percent over the whole running period of the HERMES experiment. A new dissociator (MWD) based on a microwave discharge at 2.45 GHz has been developed and installed into the HERMES-ABS in 2000. Since the velocity distribution of the MWD differs from that of the RFD the intensity could be increased further with a modified sextupole magnet system. For this purpose the way for a new start generator for sextupole tracking calculations was opened. Monte-Carlo simulations were successfully used to describe the gas expansion between nozzle, skimmer and collimator. A new type of beam monitor was used to study the beam formation after the nozzle.

  7. Cold atomic beam ion source for focused ion beam applications

    SciTech Connect

    Knuffman, B.; Steele, A. V.; McClelland, J. J.

    2013-07-28

    We report measurements and modeling of an ion source that is based on ionization of a laser-cooled atomic beam. We show a high brightness and a low energy spread, suitable for use in next-generation, high-resolution focused ion beam systems. Our measurements of total ion current as a function of ionization conditions support an analytical model that also predicts the cross-sectional current density and spatial distribution of ions created in the source. The model predicts a peak brightness of 2 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1} and an energy spread less than 0.34 eV. The model is also combined with Monte-Carlo simulations of the inter-ion Coulomb forces to show that the source can be operated at several picoamperes with a brightness above 1 × 10{sup 7} A m{sup −2} sr{sup −1} eV{sup −1}. We estimate that when combined with a conventional ion focusing column, an ion source with these properties could focus a 1 pA beam into a spot smaller than 1 nm. A total current greater than 5 nA was measured in a lower-brightness configuration of the ion source, demonstrating the possibility of a high current mode of operation.

  8. A Compact, High-Flux Cold Atom Beam Source

    NASA Technical Reports Server (NTRS)

    Kellogg, James R.; Kohel, James M.; Thompson, Robert J.; Aveline, David C.; Yu, Nan; Schlippert, Dennis

    2012-01-01

    The performance of cold atom experiments relying on three-dimensional magneto-optical trap techniques can be greatly enhanced by employing a highflux cold atom beam to obtain high atom loading rates while maintaining low background pressures in the UHV MOT (ultra-high vacuum magneto-optical trap) regions. Several techniques exist for generating slow beams of cold atoms. However, one of the technically simplest approaches is a two-dimensional (2D) MOT. Such an atom source typically employs at least two orthogonal trapping beams, plus an additional longitudinal "push" beam to yield maximum atomic flux. A 2D atom source was created with angled trapping collimators that not only traps atoms in two orthogonal directions, but also provides a longitudinal pushing component that eliminates the need for an additional push beam. This development reduces the overall package size, which in turn, makes the 2D trap simpler, and requires less total optical power. The atom source is more compact than a previously published effort, and has greater than an order of magnitude improved loading performance.

  9. A concentrated radioactive beam source for atom cooling and trapping

    SciTech Connect

    Maddi, J.; Dinneen, T.; Ghiorso, A.; Gould, H.

    1996-05-01

    The authors describe a novel oven to obtain concentrated beams of radioactive atoms. The Orthotropic oven works by ionizing atoms on its interior walls and electrostatically concentrating them on a neutralizer. Once neutralized the atoms can escape from the oven and form a narrow beam. Atoms that fail to escape become ionized again and repeat the cycle. The authors demonstrate the operation of this oven using {sup 221}Fr and compare both the theoretical and experimental efficiency of this source with standard effusive and channeled ovens.

  10. Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments

    DOE R&D Accomplishments Database

    Sibener, S. J.; Buss, R. J.; Lee, Y. T.

    1978-05-01

    A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 10{sup 17} atom sr{sup -1} sec{sup -1}. A brief discussion of the reaction dynamics of 0 + IC1 ..-->.. I0 + C1 is also presented.

  11. Design of Transversal Phase Space Meter for Atomic Hydrogen Beam Source

    NASA Astrophysics Data System (ADS)

    Belov, A. S.

    2016-02-01

    For optimization of polarized atomic beam sources apparatus it is important to have detailed information about characteristics of sources of hydrogen atoms, especially, taking into account present intensity limitations of polarized atomic beam sources. Usually, longitudinal velocity distribution of hydrogen atoms produced by RF dissociator is measured while transversal phase space of unpolarized atomic hydrogen beams was not measured up to now. In this work we report and discuss a design of transversal phase space meter for pulsed atomic hydrogen beam source. The meter design is based on “two slits” method which is well known from ion beam technique. Specific feature of the meter are movable sensitive detector of hydrogen atoms and molecules.

  12. Hypervelocity supersonic nozzle beam source of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Freedman, A.; Unkel, W.; Silver, J.; Kolb, C.

    1984-01-01

    A hypervelocity source of atomic oxygen was developed. Dissociation of molecular oxygen is accomplished by injection into a flow of helium and/or argon which has been heated in a commercial plasma torch. Atomic velocities of up to 4 kms(-1) were produced; recent improvements offer the possibility of even higher velocities. This source was utilized in studies of translational-to-vibrational energy transfer in carbon dioxide and in an investigation of the shuttle glow effect.

  13. High-intensity pulsed source of polarized protons with an atomic beam

    SciTech Connect

    Belov, A.S.; Esin, S.K.; Kubalov, S.A.; Kuzik, V.E.; Stepanov, A.A.; Yakushev, V.P.

    1985-10-25

    A source of polarized protons with a beam current up to 2.5 mA in the pulse, a degree of polarization 0.78 +- 0.01, a current pulse length of 120 ..mu..s, and a repetition frequency of 1 Hz is described. This is the first source of polarized protons which makes use of the charge exchange of polarized hydrogen atoms with ions of a deuterium plasma.

  14. Optimization of ion-atomic beam source for deposition of GaN ultrathin films

    SciTech Connect

    Mach, Jindřich Kolíbal, Miroslav; Zlámal, Jakub; Voborny, Stanislav; Bartošík, Miroslav; Šikola, Tomáš; Šamořil, Tomáš

    2014-08-15

    We describe the optimization and application of an ion-atomic beam source for ion-beam-assisted deposition of ultrathin films in ultrahigh vacuum. The device combines an effusion cell and electron-impact ion beam source to produce ultra-low energy (20–200 eV) ion beams and thermal atomic beams simultaneously. The source was equipped with a focusing system of electrostatic electrodes increasing the maximum nitrogen ion current density in the beam of a diameter of ≈15 mm by one order of magnitude (j ≈ 1000 nA/cm{sup 2}). Hence, a successful growth of GaN ultrathin films on Si(111) 7 × 7 substrate surfaces at reasonable times and temperatures significantly lower (RT, 300 °C) than in conventional metalorganic chemical vapor deposition technologies (≈1000 °C) was achieved. The chemical composition of these films was characterized in situ by X-ray Photoelectron Spectroscopy and morphology ex situ using Scanning Electron Microscopy. It has been shown that the morphology of GaN layers strongly depends on the relative Ga-N bond concentration in the layers.

  15. Bright focused ion beam sources based on laser-cooled atoms

    NASA Astrophysics Data System (ADS)

    McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

    2016-03-01

    Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review, we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.

  16. Bright focused ion beam sources based on laser-cooled atoms

    PubMed Central

    McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

    2016-01-01

    Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future. PMID:27239245

  17. An ultra-low energy (30-200 eV) ion-atomic beam source for ion-beam-assisted deposition in ultrahigh vacuum.

    PubMed

    Mach, Jindrich; Samoril, Tomás; Voborný, Stanislav; Kolíbal, Miroslav; Zlámal, Jakub; Spousta, Jirí; Dittrichová, Libuse; Sikola, Tomás

    2011-08-01

    The paper describes the design and construction of an ion-atomic beam source with an optimized generation of ions for ion-beam-assisted deposition under ultrahigh vacuum (UHV) conditions. The source combines an effusion cell and an electron impact ion source and produces ion beams with ultra-low energies in the range from 30 eV to 200 eV. Decreasing ion beam energy to hyperthermal values (≈10(1) eV) without loosing optimum ionization conditions has been mainly achieved by the incorporation of an ionization chamber with a grid transparent enough for electron and ion beams. In this way the energy and current density of nitrogen ion beams in the order of 10(1) eV and 10(1) nA/cm(2), respectively, have been achieved. The source is capable of growing ultrathin layers or nanostructures at ultra-low energies with a growth rate of several MLs/h. The ion-atomic beam source will be preferentially applied for the synthesis of GaN under UHV conditions. PMID:21895238

  18. New source of MeV negative ion and neutral atom beams.

    PubMed

    Ter-Avetisyan, S; Braenzel, J; Schnürer, M; Prasad, R; Borghesi, M; Jequier, S; Tikhonchuk, V

    2016-02-01

    The scenario of "electron-capture and -loss" was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities. PMID:26932016

  19. New source of MeV negative ion and neutral atom beams

    NASA Astrophysics Data System (ADS)

    Ter-Avetisyan, S.; Braenzel, J.; Schnürer, M.; Prasad, R.; Borghesi, M.; Jequier, S.; Tikhonchuk, V.

    2016-02-01

    The scenario of "electron-capture and -loss" was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities.

  20. Candlestick rubidium beam source

    NASA Astrophysics Data System (ADS)

    Walkiewicz, M. R.; Fox, P. J.; Scholten, R. E.

    2000-09-01

    We describe a long-lived, bright and intense rubidium atomic beam source based on a previously published recirculating candlestick design for sodium, with several modifications and enhancements. The device operates for thousands of hours without maintenance, with brightness of 1.9×1022 m-2 s-1 sr-1.

  1. High flux source of cold rubidium atoms

    NASA Astrophysics Data System (ADS)

    Slowe, Christopher; Vernac, Laurent; Hau, Lene Vestergaard

    2005-10-01

    We report on the production of a continuous, slow, and cold beam of Rb87 atoms with an extremely high flux of 3.2×1012atoms/s, a transverse temperature of 3mK, and a longitudinal temperature of 90mK. We describe the apparatus created to generate the atom beam. Hot atoms are emitted from a rubidium candlestick atomic beam source and transversely cooled and collimated by a 20cm long atomic collimator section, boosting overall beam flux by a factor of 50. The Rb atomic beam is then decelerated and longitudinally cooled by a 1m long Zeeman slower.

  2. Progress on producing polarized negative hydrogen ions by the ETHZ polarized ion source using the atomic beam method

    NASA Astrophysics Data System (ADS)

    Schmelzbach, P. A.; Grüebler, W.

    1983-03-01

    The progress on the ETHZ polarized negative hydrogen ion source, based on the atomic beam method, is described. Particular improvements have been made in the double charge exchange from positive to negative hydrogen ions. At present the source produces over 100 μA H+ ions, which yields 5-6 μA polarized negative hydrogen ions. These ions have been accelerated, in a EN tandem accelerator. A record current of 2-3 μA of polarized deuterons with 89% polarization could be focused through a 3 mm diameter collimator on a target. Further improvements incorporating presently available techniques are discussed. It is shown that 50-100 μA of polarized H- and D- ions can be produced with this type of source.

  3. Production, formation, and transport of high-brightness atomic hydrogen beam studies for the relativistic heavy ion collider polarized source upgrade

    SciTech Connect

    Kolmogorov, A. Stupishin, N.; Atoian, G.; Ritter, J.; Zelenski, A.; Davydenko, V.; Ivanov, A.

    2014-02-15

    The RHIC polarized H{sup −} ion source had been successfully upgraded to higher intensity and polarization by using a very high brightness fast atomic beam source developed at BINP, Novosibirsk. In this source the proton beam is extracted by a four-grid multi-aperture ion optical system and neutralized in the H{sub 2} gas cell downstream from the grids. The proton beam is extracted from plasma emitter with a low transverse ion temperature of ∼0.2 eV which is formed by plasma jet expansion from the arc plasma generator. The multi-hole grids are spherically shaped to produce “geometrical” beam focusing. Proton beam formation and transport of atomic beam were experimentally studied at test bench.

  4. Production, formation, and transport of high-brightness atomic hydrogen beam studies for the relativistic heavy ion collider polarized source upgrade.

    PubMed

    Kolmogorov, A; Atoian, G; Davydenko, V; Ivanov, A; Ritter, J; Stupishin, N; Zelenski, A

    2014-02-01

    The RHIC polarized H(-) ion source had been successfully upgraded to higher intensity and polarization by using a very high brightness fast atomic beam source developed at BINP, Novosibirsk. In this source the proton beam is extracted by a four-grid multi-aperture ion optical system and neutralized in the H2 gas cell downstream from the grids. The proton beam is extracted from plasma emitter with a low transverse ion temperature of ∼0.2 eV which is formed by plasma jet expansion from the arc plasma generator. The multi-hole grids are spherically shaped to produce "geometrical" beam focusing. Proton beam formation and transport of atomic beam were experimentally studied at test bench. PMID:24593468

  5. Production, formation, and transport of high-brightness atomic hydrogen beam studies for the relativistic heavy ion collider polarized source upgrade

    NASA Astrophysics Data System (ADS)

    Kolmogorov, A.; Atoian, G.; Davydenko, V.; Ivanov, A.; Ritter, J.; Stupishin, N.; Zelenski, A.

    2014-02-01

    The RHIC polarized H- ion source had been successfully upgraded to higher intensity and polarization by using a very high brightness fast atomic beam source developed at BINP, Novosibirsk. In this source the proton beam is extracted by a four-grid multi-aperture ion optical system and neutralized in the H2 gas cell downstream from the grids. The proton beam is extracted from plasma emitter with a low transverse ion temperature of ˜0.2 eV which is formed by plasma jet expansion from the arc plasma generator. The multi-hole grids are spherically shaped to produce "geometrical" beam focusing. Proton beam formation and transport of atomic beam were experimentally studied at test bench.

  6. An orthotropic source of thermal atoms

    SciTech Connect

    Dinneen, T.; Ghiorso, A.; Gould, H.

    1995-07-01

    A source of thermal atoms that emits 100% of its atoms into a narrow beam with small angular divergence is described. It uses both surface ionization and surface neutralization in conjunction with electric fields to selectively emit a highly directional (orthotropic) beam of neutral atoms. The ion recycling process can be modulated electronically and lends itself to scanning. This orthotropic source is ideal for the efficient use of rare atomic species, well suited for atomic clocks, essential in the efficient delivery of radioactive atoms to optical traps, and has potential to produce ultra high intensity beams of stable atoms.

  7. An orthotropic source of thermal atoms

    SciTech Connect

    Dinneen, T.; Ghiorso, A.; Gould, H.

    1995-06-01

    A highly efficient source that produces a narrow beam of neutral atoms at thermal velocity with small angular divergence is described. It uses a high work function interior surface to evaporate alkali atoms as ions and a low work function neutralizer, biased to collect the ions and evaporated them as neutral atoms. The neutralizer is located opposite an exit aperture so that the beam characteristics are determined by the geometry of the neutralizer and aperture. The orthotropic source is especially well suited for atomic clocks and for efficient loading of short lived radioactive alkali atoms into an optical trap.

  8. Pulsed ion beam source

    DOEpatents

    Greenly, John B.

    1997-01-01

    An improved pulsed ion beam source having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center.

  9. A continuous cold atomic beam interferometer

    SciTech Connect

    Xue, Hongbo; Feng, Yanying Yan, Xueshu; Jiang, Zhikun; Chen, Shu; Wang, Xiaojia; Zhou, Zhaoying

    2015-03-07

    We demonstrate an atom interferometer that uses a laser-cooled continuous beam of {sup 87}Rb atoms having velocities of 10–20 m/s. With spatially separated Raman beams to coherently manipulate the atomic wave packets, Mach–Zehnder interference fringes are observed at an interference distance of 2L = 19 mm. The apparatus operates within a small enclosed area of 0.07 mm{sup 2} at a bandwidth of 190 Hz with a deduced sensitivity of 7.8×10{sup −5} rad/s/√(Hz) for rotations. Using a low-velocity continuous atomic source in an atom interferometer enables high sampling rates and bandwidths without sacrificing sensitivity and compactness, which are important for applications in real dynamic environments.

  10. Numerical study of the characteristics of the ion and fast atom beams in an end-Hall ion source

    SciTech Connect

    Oudini, N.; Garrigues, L.; Hagelaar, G. J. M.; Boeuf, J. P.

    2012-10-15

    An end-Hall ion source is a cylindrical magnetized device of few centimeters in length able to generate an ion beam with a current of typically 1 A and ion energies in the range of 100 eV. This ion source does not use acceleration grids, has a relatively large ion beam divergence, and is well suited for ion assisted deposition processes. In this paper, a self-consistent two-dimensional quasi-neutral model of an end-Hall ion source is used to understand the parameters controlling the characteristics of the extracted. The model results underline the role of charge exchange collisions on beam properties. The calculated energy distribution functions reveal the existence of groups of slow ions and fast neutrals. Ion mean energy corresponds to roughly 60% of the discharge voltage, while the root mean square deviation from the mean energy corresponds to about 33% of the discharge voltage, as in experiments. The influence of the position of the electron emitting source on the ion angular distribution is also shown.

  11. Pulsed ion beam source

    DOEpatents

    Greenly, J.B.

    1997-08-12

    An improved pulsed ion beam source is disclosed having a new biasing circuit for the fast magnetic field. This circuit provides for an initial negative bias for the field created by the fast coils in the ion beam source which pre-ionize the gas in the source, ionize the gas and deliver the gas to the proper position in the accelerating gap between the anode and cathode assemblies in the ion beam source. The initial negative bias improves the interaction between the location of the nulls in the composite magnetic field in the ion beam source and the position of the gas for pre-ionization and ionization into the plasma as well as final positioning of the plasma in the accelerating gap. Improvements to the construction of the flux excluders in the anode assembly are also accomplished by fabricating them as layered structures with a high melting point, low conductivity material on the outsides with a high conductivity material in the center. 12 figs.

  12. ATOMIC BEAM STUDIES IN THE RHIC H-JET POLARIMETER.

    SciTech Connect

    MAKDISI,Y.; ZELENSKI,A.; GRAHAM,D.; KOKHANOVSKI,S.; MAHLER,G.; NASS,A.; RITTER,J.; ZUBETS,V.; ET AL.

    2005-01-28

    The results of atomic beam production studies are presented. Improved cooling of the atoms before jet formation in the dissociator cold nozzle apparently reduces the atomic beam velocity spread and improves beam focusing conditions. A carefully designed sextupole separating (and focusing) magnet system takes advantage of the high brightness source. As a result a record beam intensity of a 12.4 {center_dot} 10{sup 16} atoms/s was obtained within 10 mm acceptance at the collision point. The results of the polarization dilution factor measurements (by the hydrogen molecules at the collision point) are also presented.

  13. Compact, Continuous Beam Cold Atom Clock for Space Applications

    NASA Astrophysics Data System (ADS)

    Buell, Walter

    2000-06-01

    Highly stable atomic frequency standards are of increasing importance for a variety of space applications, ranging from communication to navigation and time transfer to tests of fundamental science. The requirements for an atomic clock vary significantly depending on the application, and for many space systems compactness and robust design are at a premium and stability dominates over absolute accuracy. We report on progress with our design for a compact Cs beam atomic clock suitable for space applications and featuring a cold atomic beam source based on a single beam, conical mirror MOT with a hole at the apex to produce a low velocity high flux atomic beam. This cold atomic beam is then used in a laser-pumped Ramsey clock, with the clock signal derived from either a microwave C-field or alternatively by Raman resonance between the Ramsey fields. The cold atom source produces a continuous beam, which relaxes requirements on the local oscillator as compared with pulsed sources. In order to reduce light shifts from the MOT light and improve signal-to-noise, the atomic beam is optically deflected and transversely cooled upon exiting the MOT's conical reflector. We estimate that the shot-noise-limited stability achievable with this physics package can be two to three orders of magnitude better than current cesium beam atomic clocks used in space applications. We present our latest experimental progress towards a working frequency standard.

  14. Dual-Beam Atom Laser Driven by Spinor Dynamics

    NASA Technical Reports Server (NTRS)

    Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Aveline, David

    2007-01-01

    An atom laser now undergoing development simultaneously generates two pulsed beams of correlated Rb-87 atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry. In this atom-laser apparatus, a Bose-Einstein condensate of about 2 x 10(exp 6) Rb-87 atoms at a temperature of about 120 micro-K is first formed through all-optical means in a relatively weak singlebeam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultrahigh-vacuum magnetooptical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped from an adjoining vacuum chamber, wherein are performed scientific observations of the beams ultimately generated by the atom laser.

  15. Atom beams split by gentle persuasion

    SciTech Connect

    Pool, R.

    1994-02-25

    Two different research teams have taken a big step toward atom interferometry. They have succeeded in splitting atomic beams by using atoms in spin states that neither absorb nor reemit laser light. By proper adjustment of experimental conditions, atoms are changed from one spin state to another, without passing through the intermediary excited state. The atoms in essence absorb momentum from the laser photons, without absorption or emission of photons. The change in momentum deflects atoms in the proper spin state.

  16. Cold Atom Source Containing Multiple Magneto-Optical Traps

    NASA Technical Reports Server (NTRS)

    Ramirez-Serrano, Jaime; Kohel, James; Kellogg, James; Lim, Lawrence; Yu, Nan; Maleki, Lute

    2007-01-01

    An apparatus that serves as a source of a cold beam of atoms contains multiple two-dimensional (2D) magneto-optical traps (MOTs). (Cold beams of atoms are used in atomic clocks and in diverse scientific experiments and applications.) The multiple-2D-MOT design of this cold atom source stands in contrast to single-2D-MOT designs of prior cold atom sources of the same type. The advantages afforded by the present design are that this apparatus is smaller than prior designs.

  17. Transverse laser cooled Lithium atomic beam for plasma edge diagnostics

    NASA Astrophysics Data System (ADS)

    Barthwal, S.; Ajmathulla; Mahender, N.; Vudayagiri, A.; Kumar, A.

    2016-05-01

    We have built a set up to achieve a collimated atomic Lithium beam to be used for plasma edge diagnostics. The collimation is achieved by two-dimensional laser cooling, and such a beam could be very useful to obtain electron density at the edge of a plasma with very high spatial resolution. We present in this manuscript the details of this setup, including details of the oven we designed for the Lithium source. We present the metrics of the beam, including the transverse velocity profile of the atomic beam.

  18. High-brilliance Zeeman-slowed cesium atomic beam

    NASA Astrophysics Data System (ADS)

    Lison, F.; Schuh, P.; Haubrich, D.; Meschede, D.

    2000-01-01

    We have built a Zeeman-slower apparatus which produces a slow and cold cesium atomic beam. The atomic beam has a mean velocity in the range 35-120 m/s and a high atomic current of more than 2×1010 cold atoms/s. A small longitudinal velocity spread was achieved by optimizing the termination of the slowing process. The measured value of less than 1 m/s is consistent with a numerical simulation of the slowing process. With a magnetic lens and a tilted two-dimensional optical molasses stage, the slow atomic beam is transversely compressed, collimated, and deflected. We achieve a transverse temperature below the Doppler limit. The brilliance of this beam has been determined to be 7×1023 atoms s-1m-2 sr-1. By optical pumping the slow atomic beam can be polarized in the outermost magnetic substates F=4,mF=+/-4, of the cesium ground state. This brilliant beam is an ideal source for experiments in atom optics and atom lithography.

  19. Pulsed source of energetic atomic oxygen

    NASA Technical Reports Server (NTRS)

    Caledonia, George E.; Krech, Robert H.

    1987-01-01

    A pulsed high flux source of nearly monoenergetic atomic oxygen was designed, built, and successfully demonstrated. Molecular oxygen at several atmospheres pressure is introduced into an evacuated supersonic expansion nozzle through a pulsed molecular beam valve. An 18 J pulsed CO2 TEA laser is focused to intensities greater than 10(9) W/sq cm in the nozzle throat to generate a laser-induced breakdown. The resulting plasma is heated in excess of 20,000 K by a laser supported detonation wave, and then rapidly expands and cools. Nozzle geometry confines the expansion to provide rapid electron-ion recombination into atomic oxygen. Average O atom beam velocities from 5 to 13 km/s were measured at estimated fluxes to 10(18) atoms per pulse. Preliminary materials testing has produced the same surface oxygen enrichment in polyethylene samples as obtained on the STS-8 mission. Scanning electron microscope examinations of irradiated polymer surfaces reveal an erosion morphology similar to that obtained in low Earth orbit, with an estimated mass removal rate of approx. 10(-24) cu cm/atom. The characteristics of the O atom source and the results of some preliminary materials testing studies are reviewed.

  20. Method for producing an atomic oxygen beam

    NASA Technical Reports Server (NTRS)

    Outlaw, Ronald A. (Inventor)

    1989-01-01

    A method for producing an atomic oxygen beam is provided by the present invention. First, a material 10' is provided which dissociates molecular oxygen and dissolves atomic oxygen into its bulk. Next, molecular oxygen is exposed to entrance surface 11' of material 10'. Next, material 10' is heated by heater 17' to facilitate the permeation of atomic oxygen through material 10' to the UHV side 12'. UHV side 12' is interfaced with an ultra-high vacuum (UHV) environment provided by UHV pump 15'. The atomic oxygen on the UHV side 12' is excited to a non-binding state by exciter 14' thus producing the release of atomic oxygen to form an atomic oxygen beam 35'.

  1. Loss of atomic oxygen in mass spectrometer ion sources.

    NASA Technical Reports Server (NTRS)

    Lake, L. R.; Nier, A. O.

    1973-01-01

    A gas beam consisting of a mixture of atomic and molecular oxygen has been directed at the ion source of a mass spectrometer like those used in sounding rockets for determining the neutral composition of the lower thermosphere. The loss of atomic oxygen on mass spectrometer surfaces was evaluated by flagging the beam in several ways and comparing the experimental results with predicted values. The results obtained suggest that in rocket flights using similar instruments the atomic oxygen densities computed assuming no-loss conditions may be low by a factor of 2.5. Studies made using a beam containing tracer O-18 indicate that carbon dioxide observed when atomic oxygen enters the source is formed in a reaction involving atomic oxygen from the beam and carbon monoxide from the surfaces bombarded.

  2. Relativistic atomic beam spectroscopy II

    SciTech Connect

    1989-12-31

    The negative ion of H is one of the simplest 3-body atomic systems. The techniques we have developed for experimental study of atoms moving near speed of light have been productive. This proposal request continuing support for experimental studies of the H{sup -} system, principally at the 800 MeV linear accelerator (LAMPF) at Los Alamos. Four experiments are currently planned: photodetachment of H{sup -} near threshold in electric field, interaction of relativistic H{sup -} ions with matter, high excitations and double charge escape in H{sup -}, and multiphoton detachment of electrons from H{sup -}.

  3. Relativistic atomic beam spectroscopy II

    SciTech Connect

    1991-12-31

    We are requesting support for a postdoctoral person to participate in H{sup -} studies at Los Alamos. In addition, we are requesting funding for a state-of-the-art YAG laser system that would allow us to obtain data at three times our present rate with improved beam quality.

  4. An MCNPX accelerator beam source

    SciTech Connect

    Durkee, Joe W.; Elson, Jay S.; Jason, Andrew; Johns, Russell C.; Waters, Laurie S.

    2009-06-04

    MCNPX is a powerful Monte Carlo code that can be used to conduct sophisticated radiation-transport simulations involving complex physics and geometry. Although MCNPX possesses a wide assortment of standardized modeling tools, there are instances in which a user's needs can eclipse existing code capabilities. Fortunately, although it may not be widely known, MCNPX can accommodate many customization needs. In this article, we demonstrate source-customization capability for a new SOURCE subroutine as part of our development to enable simulations involving accelerator beams for active-interrogation studies. Simulation results for a muon beam are presented to illustrate the new accelerator-source capability.

  5. Electron beam ion sources and traps (invited)

    NASA Astrophysics Data System (ADS)

    Becker, Reinard

    2000-02-01

    The electron beam method of stepwise ionization to highest charge states has found applications in electron beam ion sources (EBISs) for accelerators and atomic physics collision experiments as well as in electron beam ion traps (EBITs) for x-ray and mass spectroscopy. A dense and almost monoenergetic electron beam provides a unique tool for ionization, because radiative recombination by slow electrons is negligible and charge exchange is almost avoided in ultrahigh vacua. These are essential differences to electron cyclotron resonance ion sources with inevitable low energy electrons and comparatively high gas pressure. The distinction between EBIS and EBIT as genuine devices has become meaningless, because EBISs may work as traps and almost all EBITs are feeding beamlines for external experiments. More interesting is to note the diversification of these devices, which demonstrates that a matured technology is finding dedicated answers for different applications. At present we may distinguish six major lines of development and application: high current EBISs for upcoming hadron colliders, super EBITs in the energy range above 300 keV for quantum electrondynamics tests, inexpensive and small EBISTs for atomic physics studies, a highly efficient EBIS with oscillating electrons, MEDEBIS for tumor therapy with C6+, and charge breeding in facilities for exotic radioactive beams.

  6. Generation of a Cold Atom Beam from a Pyramidal Magneto-Optical Trap

    NASA Technical Reports Server (NTRS)

    Bliss, J. L.; Libbrecht, K. G.; Maleki, Klipstein L.

    2000-01-01

    We have built an atomic beam source utilizing a simple and robust design based on the pyramidal trap geometry of Kim et al. Our design allows use of a single large diameter (\\le20 cm) laser beam to obtain large capture rates of atoms from a background vapor. A small (about 1mm diameter) hole in the retro-optic at the apex of the pyramid provides an extraction column for the atoms. We have operated the apparatus both as a magneto-optical trap (using an auxiliary plug laser beam), and as a cold atomic beam source. The characterization of this large pyramidal beam source will be reported, including an investigation of scaling to very large (10--20cm) high power (about 1W) laser beams which should allow significant improvements in atomic beam flux.

  7. Beam Quality of a Nonideal Atom Laser

    SciTech Connect

    Riou, J.-F.; Guerin, W.; Le Coq, Y.; Fauquembergue, M.; Josse, V.; Bouyer, P.; Aspect, A.

    2006-02-24

    We study the propagation of a noninteracting atom laser distorted by the strong lensing effect of the Bose-Einstein condensate (BEC) from which it is outcoupled. We observe a transverse structure containing caustics that vary with the density within the residing BEC. Using the WKB approximation, Fresnel-Kirchhoff integral formalism, and ABCD matrices, we are able to describe analytically the atom-laser propagation. This allows us to characterize the quality of the nonideal atom-laser beam by a generalized M{sup 2} factor defined in analogy to photon lasers. Finally we measure this quality factor for different lensing effects.

  8. Enabling Nanotechnology with Focused Ion Beams from Laser Cooled Atoms

    NASA Astrophysics Data System (ADS)

    Steele, A. V.; Knuffman, B.; Orloff, J.; Maazouz, M.; McClelland, J. J.

    2011-05-01

    The Magneto-Optical Trap Ion Source (MOTIS) being developed at NIST has the potential to enable numerous advances in nanoscale science. In a MOTIS, atoms are captured into a MOT, photoionized, and accelerated to an energy of a few hundred eV to a few tens of kV. A beam formed in this way can be brought to a tight focus, competitive with the commercial focused ion beam machines deployed widely today. Additionally, the unique characteristics of this source, coupled with the user's choice of ion from the long and growing list of laser-coolable atomic species suggest that the MOTIS has the potential to advance the state of the art in applications such as imaging, nanofabrication, secondary ion mass spectrometry, and others. I will present high-resolution images from our lithium and chromium MOTIS-based focused ion beams and discuss applications which we will pursue with these new tools.

  9. Random sources for cusped beams.

    PubMed

    Li, Jia; Wang, Fei; Korotkova, Olga

    2016-08-01

    We introduce two novel classes of partially coherent sources whose degrees of coherence are described by the rectangular Lorentz-correlated Schell-model (LSM) and rectangular fractional multi-Gaussian-correlated Schell-model (FMGSM) functions. Based on the generalized Collins formula, analytical expressions are derived for the spectral density distributions of these beams propagating through a stigmatic ABCD optical system. It is shown that beams belonging to both classes form the spectral density apex that is much higher and sharper than that generated by the Gaussian Schell-model (GSM) beam with a comparable coherence state. We experimentally generate these beams by using a nematic, transmissive spatial light modulator (SLM) that serves as a random phase screen controlled by a computer. The experimental data is consistent with theoretical predictions. Moreover, it is illustrated that the FMGSM beam generated in our experiments has a better focusing capacity than the GSM beam with the same coherence state. The applications that can potentially benefit from the use of novel beams range from material surface processing, to communications and sensing through random media. PMID:27505746

  10. Laboratory Apparatus Generates Dual-Species Cold Atomic Beam

    NASA Technical Reports Server (NTRS)

    Thompson, Robert; Klipstein, William; Kohel, James; Maleki, Lute; Lundblad, Nathan; Ramirez-Serrano, Jaime; Aveline, Dave; Yu, Nan; Enzer, Daphna

    2004-01-01

    A laser cooling apparatus that generates a cold beam of rubidium and cesium atoms at low pressure has been constructed as one of several intermediate products of a continuing program of research on laser cooling and atomic physics. Laser-cooled atomic beams, which can have temperatures as low as a microkelvin, have been used in diverse applications that include measurements of fundamental constants, atomic clocks that realize the international standard unit of time, atom-wave interferometers, and experiments on Bose-Einstein condensation. The present apparatus is a prototype of one being evaluated for use in a proposed microgravitational experiment called the Quantum Interferometric Test of Equivalence (QuITE). In this experiment, interferometric measurements of cesium and rubidium atoms in free fall would be part of a test of Einstein s equivalence principle. The present apparatus and its anticipated successors may also be useful in other experiments, in both microgravity and normal Earth gravity, in which there are requirements for dual-species atomic beams, low temperatures, and low pressures. The apparatus includes a pyramidal magneto-optical trap in which the illumination is provided by multiple lasers tuned to frequencies characteristic of the two atomic species. The inlet to the apparatus is located in a vacuum chamber that contains rubidium and cesium atoms at a low pressure; the beam leaving through the outlet of the apparatus is used to transfer the atoms to a higher-vacuum (lower-pressure) chamber in which measurements are performed. The pyramidal magneto-optical trap is designed so that the laser cooling forces in one direction are unbalanced, resulting in a continuous cold beam of atoms that leak out of the trap (see figure). The radiant intensity (number of atoms per unit time per unit solid angle) of the apparatus is the greatest of any other source of the same type reported to date. In addition, this is the first such apparatus capable of producing

  11. Atomic physics at the advanced photon source

    SciTech Connect

    Berry, H.G.; Cowan, P.L.; Gemmell, D.S.

    1995-08-01

    Argonne`s 7-GeV synchrotron light source (APS) is expected to commence operations for research early in FY 1996. The Basic Energy Sciences Synchrotron Research Center (BESSRC) is likewise expected to start its research programs at that time. As members of the BESSRC CAT (Collaborative Access Team), we are preparing, together with atomic physicists from the University of Western Michigan, the University of Tennessee, and University of Notre Dame, to initiate a series of atomic physics experiments that exploit the unique capabilities of the APS, especially its high brilliance for photon energies extending from about 3 keV to more than 50 keV. Most of our early work will be conducted on an undulator beam line and we are thus concentrating on various aspects of that beam line and its associated experimental areas. Our group has undertaken responsibilities in such areas as hutch design, evaluation of undulator performance, user policy, interfacing and instrumentation, etc. Initial experiments will probably utilize existing apparatus. We are, however, planning to move rapidly to more sophisticated measurements involving, for example, ion-beam targets, simultaneous laser excitation, and the spectroscopy of emitted photons.

  12. Nanoscale atomic lithography with a cesium atomic beam

    NASA Astrophysics Data System (ADS)

    Lison, F.; Adams, H.-J.; Haubrich, D.; Kreis, M.; Nowak, S.; Meschede, D.

    1997-09-01

    We have demonstrated the lithographic production of a periodic nanostructure by focusing a transversely laser cooled cesium atomic beam with a standing-wave light field. With a self-assembled monolayer used as the resist on a gold surface, exposure to cesium atoms locally changes the wetability. Subsequently a wet-etching process transfers the pattern to the underlying gold film. We have generated lines with a separation of half the wavelength of the cesium D2 line (852 nm) and a width of about 120 nm and covering a large area of approximately 1 mm2.

  13. Development of francium atomic beam for the search of the electron electric dipole moment

    NASA Astrophysics Data System (ADS)

    Sato, Tomoya; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kato, T.; Kawamura, H.; Nataraj, H. S.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

    2014-03-01

    For the measurement of the electron electric dipole moment using Fr atoms, a Fr ion-atom conversion is one of the most critical process. An ion-atom converter based on the "orthotropic" type of Fr source has been developed. This converter is able to convert a few keV Fr ion beam to a thermal atomic beam using a cycle of the surface ionization and neutralization. In this article, the development of the converter is reported.

  14. Beam transport of low temperature atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Kaufman, W. A.

    1993-12-01

    Analytic calculations and particle tracking simulations are presented for a polarized atomic hydrogen beam produced by extraction from an ultra-cold (T=300 mK) helium film coated cell in a large solenoidal magnetic field (12 T). Initial focusing of states 1 and 2 by the solenoidal field and subsequent focusing by a sextupole are examined within the constraints imposed by the requirements of the polarized jet for the experiments NEPTUN and NEPTUN-A at UNK.

  15. Atomic beam scattering from single crystal surfaces

    NASA Astrophysics Data System (ADS)

    Frankl, Daniel R.

    Application of atom-scattering to a variety of surface problems is expanding rapidly, owing in large part to the extreme surface- sensitivity of this probe. Helium is particularly useful because of its low mass and chemical inertness. Beams with velocity spreads of less than one percent and wavelength of the order of one Angstrom can be formed by nozzle expansion. The scattered flux from a clean, well-ordered crystal surface contains elastic and inelastic, coherent and incoherent, components. The coherent elastic component (i.e., the specular and diffracted beams) contains information about the crystallographic structure of the outer- most atomic layer of the crystal and about the interaction potential between the crystal and the scattered particle. The latter manifests itself in the form of resonances between the incoming free-particle state, and the two-dimensional Bloch states bound in the potential well at the surface. Elastic scattering theory has reached the point where the resonance signatures in the various diffracted beams can be predicted accurately. Crystallographic information resides in the diffracted beam intensities. Theoretical interpretation is less well advanced, though some progress has been made with “hard-wall” models. Experimental studies of reconstructed surfaces and chemisorbed overlayers appear very promising. In inelastic scattering, energy resolution has been achieved by both time-of-flight and diffraction methods. High-resolution studies on alkali halide surfaces have led to experimental determination of Rayleighwave dispersion relations over the full Brillouin zone. Preliminary results have also been obtained on some metals.

  16. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    NASA Astrophysics Data System (ADS)

    Chanu, Sapam Ranjita; Rathod, Ketan D.; Natarajan, Vasant

    2016-08-01

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in optical molasses by turning off the MOT magnetic field before the transfer beams are turned on.

  17. An improved high intensity recycling helium-3 beam source

    SciTech Connect

    Hedgeland, H.; Kole, P. R.; Allison, W.; Ellis, J.; Jardine, A. P.

    2009-07-15

    We describe an improved high intensity, recycling, supersonic atomic beam source. Changes address several issues previously limiting performance and reliability of the apparatus, including the use of newly available vacuum pumps and modifications to the recycling system. We achieve a source intensity of 2.5x10{sup 19} atoms/s/sr, almost twice that previously achievable during recycling. Current limits on intensity are discussed.

  18. An improved high intensity recycling helium-3 beam source.

    PubMed

    Hedgeland, H; Kole, P R; Allison, W; Ellis, J; Jardine, A P

    2009-07-01

    We describe an improved high intensity, recycling, supersonic atomic beam source. Changes address several issues previously limiting performance and reliability of the apparatus, including the use of newly available vacuum pumps and modifications to the recycling system. We achieve a source intensity of 2.5 x 10(19) atoms/s/sr, almost twice that previously achievable during recycling. Current limits on intensity are discussed. PMID:19655995

  19. Metastable Krypton Beam Source via Two-Photon Pumping Technique

    SciTech Connect

    Wong, W.W.; Young, L.

    2003-01-01

    Metastable beams of rare gas atoms have wide applications in chemical analysis of samples, as well as in aiding understanding of fundamental processes and physical attributes. Most current sources of metastable rare gas atomic beams, however, are limited in their flux density, which greatly reduces their utility in applications such as low level trace analysis and precision measurements. Previous work has demonstrated feasibility of metastable krypton production via two-photon pumping, and this paper extends that possibility into beam form. Further optimization on this scheme, moreover, promises 100-fold increase of metastable krypton flux density over that of an rf-driven discharge.

  20. Stopping supersonic beams with a series of pulsed electromagnetic coils: an atomic coilgun.

    PubMed

    Narevicius, Edvardas; Libson, Adam; Parthey, Christian G; Chavez, Isaac; Narevicius, Julia; Even, Uzi; Raizen, Mark G

    2008-03-01

    We report the stopping of an atomic beam, using a series of pulsed electromagnetic coils. We use a supersonic beam of metastable neon created in a gas discharge as a monochromatic source of paramagnetic atoms. A series of coils is fired in a timed sequence to bring the atoms to near rest, where they are detected on a microchannel plate. Applications to fundamental problems in physics and chemistry are discussed. PMID:18352704

  1. Stopping Supersonic Beams with a Series of Pulsed Electromagnetic Coils: An Atomic Coilgun

    NASA Astrophysics Data System (ADS)

    Narevicius, Edvardas; Libson, Adam; Parthey, Christian G.; Chavez, Isaac; Narevicius, Julia; Even, Uzi; Raizen, Mark G.

    2008-03-01

    We report the stopping of an atomic beam, using a series of pulsed electromagnetic coils. We use a supersonic beam of metastable neon created in a gas discharge as a monochromatic source of paramagnetic atoms. A series of coils is fired in a timed sequence to bring the atoms to near rest, where they are detected on a microchannel plate. Applications to fundamental problems in physics and chemistry are discussed.

  2. Production of high brightness H- beam by charge exchange of hydrogen atom beam in sodium jet

    SciTech Connect

    Davydenko, V.; Zelenski, A.; Ivanov, A.; Kolmogorov, A.

    2010-11-16

    Production of H{sup -} beam for accelerators applications by charge exchange of high brightness hydrogen neutral beam in a sodium jet cell is experimentally studied in joint BNL-BINP experiment. In the experiment, a hydrogen-neutral beam with 3-6 keV energy, equivalent current up to 5 A and 200 microsecond pulse duration is used. The atomic beam is produced by charge exchange of a proton beam in a pulsed hydrogen target. Formation of the proton beam is performed in an ion source by four-electrode multiaperture ion-optical system. To achieve small beam emittance, the apertures in the ion-optical system have small enough size, and the extraction of ions is carried out from the surface of plasma emitter with a low transverse ion temperature of {approx}0.2 eV formed as a result of plasma jet expansion from the arc plasma generator. Developed for the BNL optically pumped polarized ion source, the sodium jet target with recirculation and aperture diameter of 2 cm is used in the experiment. At the first stage of the experiment H{sup -} beam with 36 mA current, 5 keV energy and {approx}0.15 cm {center_dot} mrad normalized emittance was obtained. To increase H{sup -} beam current ballistically focused hydrogen neutral beam will be applied. The effects of H{sup -} beam space-charge and sodium-jet stability will be studied to determine the basic limitations of this approach.

  3. Note: Design principles of a linear array multi-channel effusive metal-vapor atom source

    SciTech Connect

    Jana, B.; Majumder, A.; Thakur, K. B.; Das, A. K.

    2013-10-15

    Atomic beams can easily be produced by allowing atoms to effuse through a channel. In an earlier investigation [A. Majumder et al., Vacuum 83, 989 (2009)], we had designed, fabricated, and characterized an effusive metal-vapor source using collinear-array of multi-channel. In this note, we describe the theoretical basis of designing the source. Atom density in atomic beam has been estimated using a set of analytical expressions for long-channel operated in transparent mode. Parametric studies on aspect ratio of channel, inter-channel separation, beam width, and vertical distance from the source are carried out. They are useful in providing physical picture and optimizing design parameters.

  4. Programmable solid state atom sources for nanofabrication

    NASA Astrophysics Data System (ADS)

    Han, Han; Imboden, Matthias; Stark, Thomas; Del Corro, Pablo G.; Pardo, Flavio; Bolle, Cristian A.; Lally, Richard W.; Bishop, David J.

    2015-06-01

    In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques.In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques. Electronic supplementary information (ESI) available: A document containing further information about device characterization

  5. Generation of a Cold Atom Beam from a Pyramidal Magneto-Optical Trap

    NASA Technical Reports Server (NTRS)

    Kohel, J.; Thompson, R. J.; Seidel, D. J.; Klipstein, W. M.; Maleki, L.; Bliss, J.; Libbrecht, K. G.

    2000-01-01

    Techniques to generate cold atom beams are of great interest in a variety of applications, from atomic frequency standards and atom optics to experimental studies of Bose-Einstein condensation. Cold atom beams have been produced by slowing thermal atomic beams using the Zeeman-slowing technique or chirped lasers, or using laser-cooling techniques to extract a slow atomic beam from the background gas in a low-pressure vapor cell. These laser-cooling techniques include "atomic funnels" or two-dimensional magneto-optical traps, as well as a variation of the conventional vapor cell magneto-optical trap called the "low-velocity intense source" (LVIS). Variations of the LVIS have been realized with unique trap geometries such as conical or pyramidal mirror traps. The present work implements a simple and robust design based on the pyramidal trap geometry and allows use of a single large diameter (beam to obtain large capture rates of atoms from the background vapor. The four 45 deg mirrors are truncated just before the apex of the pyramid, and the 1 sq cm region at the center of the incident laser beam is retro-reflected by lambda /4 plate with a high-reflectance gold coating on the second surface. A small (1 mm diameter) hole in this retro-optic forms an extraction column for the atoms while maintaining a low conductance between the source region and an adjacent UHV chamber.

  6. Continuous beam of laser-cooled Yb atoms

    NASA Astrophysics Data System (ADS)

    Rathod, K. D.; Singh, Alok K.; Natarajan, Vasant

    2013-05-01

    We demonstrate the launching of laser-cooled Yb atoms in a continuous atomic beam. The continuous cold beam has significant advantages over the more-common pulsed fountain, which was also demonstrated by us recently. The cold beam is formed in the following steps: i) atoms from a thermal beam are first Zeeman-slowed to a small final velocity; ii) the slowed atoms are captured in a two-dimensional magneto-optic trap (2D-MOT); and iii) atoms are launched continuously in the vertical direction using two sets of moving-molasses beams, inclined at ±15° to the vertical. The cooling transition used is the strongly allowed {^1S}_0 \\rightarrow {^1P}_1 transition at 399 nm. We capture about 7 × 106 atoms in the 2D-MOT, and then launch them with a vertical velocity of 13 m/s at a longitudinal temperature of 125(6) mK.

  7. Variable energy, high flux, ground-state atomic oxygen source

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara (Inventor); Orient, Otto J. (Inventor)

    1987-01-01

    A variable energy, high flux atomic oxygen source is described which is comprised of a means for producing a high density beam of molecules which will emit O(-) ions when bombarded with electrons; a means of producing a high current stream of electrons at a low energy level passing through the high density beam of molecules to produce a combined stream of electrons and O(-) ions; means for accelerating the combined stream to a desired energy level; means for producing an intense magnetic field to confine the electrons and O(-) ions; means for directing a multiple pass laser beam through the combined stream to strip off the excess electrons from a plurality of the O(-) ions to produce ground-state O atoms within the combined stream; electrostatic deflection means for deflecting the path of the O(-) ions and the electrons in the combined stream; and, means for stopping the O(-) ions and the electrons and for allowing only the ground-state O atoms to continue as the source of the atoms of interest. The method and apparatus are also adaptable for producing other ground-state atoms and/or molecules.

  8. Low energy ion beam dynamics of NANOGAN ECR ion source

    NASA Astrophysics Data System (ADS)

    Kumar, Sarvesh; Mandal, A.

    2016-04-01

    A new low energy ion beam facility (LEIBF) has been developed for providing the mass analyzed highly charged intense ion beams of energy ranging from a few tens of keV to a few MeV for atomic, molecular and materials sciences research. The new facility consists of an all permanent magnet 10 GHz electron cyclotron resonance (ECR) ion source (NANOGAN) installed on a high voltage platform (400 kV) which provides large currents of multiply charged ion beams. Higher emittance at low energy of intense ion beam puts a tremendous challenge to the beam optical design of this facility. The beam line consists of mainly the electrostatic quadrupoles, an accelerating section, analyzing cum switching magnet and suitable beam diagnostics including vacuum components. The accelerated ion beam is analyzed for a particular mass to charge (m/q) ratio as well as guided to three different lines along 75°, 90° and 105° using a large acceptance analyzing cum switching magnet. The details of transverse beam optics to all the beam lines with TRANSPORT and GICOSY beam optics codes are being described. Field computation code, OPERA 3D has been utilized to design the magnets and electrostatic quadrupoles. A theoretical estimation of emittance for optimized geometry of ion source is given so as to form the basis of beam optics calculations. The method of quadrupole scan of the beam is used to characterize the emittance of the final beam on the target. The measured beam emittance increases with m/q ratios of various ion beams similar to the trend observed theoretically.

  9. Caborane beam from ITEP Bernas ion source for semiconductor implanters

    SciTech Connect

    Seleznev, D.; Hershcovitch, A.; Kropachev, G.; Kozlov, A.; Kuibeda, R.; Koshelev, V.; Kulevoy, T.; Jonson, B.; Poole, J.; Alexeyenko, O.; Gurkova, E.; Oks, E.; Gushenets, V.; Polozov, S.; Masunov, E.

    2010-02-01

    A joint research and development of steady state intense boron ion sources for hundreds of electron-volt ion implanters has been in progress for the past 5 years. The difficulties of extraction and transportation of low energy boron beams can be solved by implanting clusters of boron atoms. In Institute for Theoretical and Experimental Physics (ITEP) the Bernas ion source successfully generated the beam of decaborane ions. The carborane (C{sub 2}B{sub 10}H{sub 12}) ion beam is more attractive material due to its better thermal stability. The results of carborane ion beam generation are presented. The result of the beam implantation into the silicon wafer is presented as well.

  10. Scattering of dilute thermal atom clouds on optical Weber beams

    NASA Astrophysics Data System (ADS)

    Hernández-Cedillo, C. L.; Bernon, S.; Hattermann, H.; Fortágh, J.; Jáuregui, R.

    2013-02-01

    We report the experimental observation and a theoretical description of the scattering of free falling dilute thermal clouds of 87Rb atoms by microscopically structured light beams with parabolic-cylindrical symmetry. These structured beams are known in the literature as Weber beams. High-fidelity Weber beams are generated by means of a spatial light modulator and an annular spatial filtering process, which yields a quasipropagation-invariant electromagnetic field in the region of interaction with the atom cloud. The dynamics of the atomic density profile and the phase space distribution of the scattered atoms is explored. A natural dynamical variable of Weber modes is the product of the angular momentum along the axis of propagation of the beam with a component of linear momentum perpendicular to that axis. To pave the way of the understanding about the transfer of this variable, we study the evolution of the analogous atomic variable.

  11. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide

    PubMed Central

    Sadgrove, Mark; Wimberger, Sandro; Nic Chormaic, Síle

    2016-01-01

    We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold 23Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry. PMID:27440516

  12. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide.

    PubMed

    Sadgrove, Mark; Wimberger, Sandro; Nic Chormaic, Síle

    2016-01-01

    We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold (23)Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry. PMID:27440516

  13. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide

    NASA Astrophysics Data System (ADS)

    Sadgrove, Mark; Wimberger, Sandro; Nic Chormaic, Síle

    2016-07-01

    We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold 23Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry.

  14. Metal Ion Sources for Ion Beam Implantation

    SciTech Connect

    Zhao, W. J.; Zhao, Z. Q.; Ren, X. T.

    2008-11-03

    In this paper a theme touched upon the progress of metal ion sources devoted to metal ion beam implantation (MIBI) will be reviewed. A special emphasis will be given to some kinds of ion sources such as ECR, MEVVA and Cluster ion sources. A novel dual hollow cathode metal ion source named DUHOCAMIS will be introduced and discussed.

  15. Versatile atomic force microscopy setup combined with micro-focused X-ray beam

    NASA Astrophysics Data System (ADS)

    Slobodskyy, T.; Zozulya, A. V.; Tholapi, R.; Liefeith, L.; Fester, M.; Sprung, M.; Hansen, W.

    2015-06-01

    Micro-focused X-ray beams produced by third generation synchrotron sources offer new perspective of studying strains and processes at nanoscale. Atomic force microscope setup combined with a micro-focused synchrotron beam allows precise positioning and nanomanipulation of nanostructures under illumination. In this paper, we report on integration of a portable commercial atomic force microscope setup into a hard X-ray synchrotron beamline. Details of design, sample alignment procedure, and performance of the setup are presented.

  16. Versatile atomic force microscopy setup combined with micro-focused X-ray beam

    SciTech Connect

    Slobodskyy, T. Tholapi, R.; Liefeith, L.; Hansen, W.; Zozulya, A. V. Fester, M.; Sprung, M.

    2015-06-15

    Micro-focused X-ray beams produced by third generation synchrotron sources offer new perspective of studying strains and processes at nanoscale. Atomic force microscope setup combined with a micro-focused synchrotron beam allows precise positioning and nanomanipulation of nanostructures under illumination. In this paper, we report on integration of a portable commercial atomic force microscope setup into a hard X-ray synchrotron beamline. Details of design, sample alignment procedure, and performance of the setup are presented.

  17. Continuum source tungsten coil atomic fluorescence spectrometry.

    PubMed

    Gu, Jiyan; Donati, George L; Young, Carl G; Jones, Bradley T

    2011-04-01

    A simple continuum source tungsten coil atomic fluorescence spectrometer is constructed and evaluated. The heart of the system is the atomizer: a low-cost tungsten filament extracted from a 150 W light bulb. The filament is resistively heated with a small, solid-state, constant-current power supply. The atomizer is housed in a glass chamber and purged with a 1 L/min flow of a conventional welding gas mixture: 10% H(2)/Ar. A 25 μL sample aliquot is pipetted onto the tungsten coil, the liquid is dried at low current, and then the atomic vapor is produced by applying a current in the range 3.5-5.5 A. The atomization current does not produce temperatures high enough to excite atomic emission. Radiation from a 300 W xenon lamp is focused through the atomic vapor, exciting atomic fluorescence. Fluorescence signals are collected using a hand-held charge-coupled device (CCD) spectrometer. Simultaneous determination of ten elements (Ag, Bi, Cr, Cu, Ga, In, Mg, Mn, and Tl) results in detection limits in the range 0.3 to 10 ng. The application of higher atomization currents (10 A) leads to straightforward detection of atomic emission signals with no modifications to the instrument. PMID:21396184

  18. Compact 2.45 GHz microwave ion/atom source

    SciTech Connect

    Sakamoto, Y.; Kasuya, T.; Wada, M.; Maeno, S.

    2008-02-15

    Characteristics of a microwave driven 3.4 cm diameter compact ion/atom source equipped with permanent magnets were tested. The source can be mounted to a standard copper gasket flange, and microwave power is supplied through an N-type microwave connector. The ion source plasma was observed through an ion extraction hole with an optical emission spectrometer. Peak height of an optical line spectrum emission corresponding to atomic nitrogen increased in proportion to the microwave input power. Quadrupole mass spectrometer showed that N{sup +} and N{sub 2}{sup +} were the dominant species in the extracted ion beam. Nitrogen ion current density of 0.23 mA/cm{sup 2} was obtained with only 10 W discharge power and 6x10{sup -3} Pa source surrounding pressure.

  19. Novel cryogenic sources for liquid droplet and solid filament beams

    NASA Astrophysics Data System (ADS)

    Grams, Michael P.

    Two novel atomic and molecular beam sources have been created and tested consisting first of a superfluid helium liquid jet, and secondly a solid filament of argon. The superfluid helium apparatus is the second of its kind in the world and uses a modified liquid helium cryostat to inject a cylindrical stream of superfluid helium into vacuum through glass capillary nozzles with diameters on the order of one micron created on-site at Arizona State University. The superfluid beam is an entirely new way to study superfluid behavior, and has many new applications such as superfluid beam-surface scattering, beam-beam scattering, and boundary-free study of superfluidity. The solid beam of argon is another novel beam source created by flowing argon gas through a capillary 50 microns in diameter which is clamped by a small copper plate to a copper block kept at liquid nitrogen temperature. The gas subsequently cools and solidifies plugging the capillary. Upon heating, the solid plug melts and liquid argon exits the capillary and immediately freezes by evaporative cooling. The solid filaments may find application as wall-less cryogenic matrices, or targets for laser plasma sources of extreme UV and soft x-ray sources.

  20. Discrimination of ionic species from broad-beam ion sources

    NASA Technical Reports Server (NTRS)

    Anderson, J. R.

    1993-01-01

    The performance of a broad-beam, three-grid, ion extraction system incorporating radio frequency (RF) mass discrimination was investigated experimentally. This testing demonstrated that the system, based on a modified single-stage Bennett mass spectrometer, can discriminate between ionic species having about a 2-to-1 mass ratio while producing a broad-beam of ions with low kinetic energy (less than 15 eV). Testing was conducted using either argon and krypton ions or atomic and diatomic oxygen ions. A simple one-dimensional model, which ignores magnetic field and space-charge effects, was developed to predict the species separation capabilities as well as the kinetic energies of the extracted ions. The experimental results correlated well with the model predictions. This RF mass discrimination system can be used in applications where both atomic and diatomic ions are produced, but a beam of only one of the species is desired. An example of such an application is a 5 eV atomic oxygen source. This source would produce a beam of atomic oxygen with 5 eV kinetic energy, which would be directed onto a material specimen, to simulate the interaction between the surface of a satellite and the rarefied atmosphere encountered in low-Earth orbit.

  1. Electron beam ion source and electron beam ion trap (invited)

    SciTech Connect

    Becker, Reinard; Kester, Oliver

    2010-02-15

    The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not ''sorcery'' but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

  2. The Electron Beam Ion Source (EBIS)

    ScienceCinema

    Brookhaven Lab

    2010-01-08

    Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

  3. The Electron Beam Ion Source (EBIS)

    SciTech Connect

    Brookhaven Lab

    2009-06-09

    Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

  4. Pattern generation with cesium atomic beams at nanometer scales

    NASA Astrophysics Data System (ADS)

    Kreis, M.; Lison, F.; Haubrich, D.; Meschede, D.; Nowak, S.; Pfau, T.; Mlynek, J.

    1996-12-01

    We have demonstrated that a cesium atomic beam can be used to pattern a gold surface using a self assembling monolayer (SAM) as a resist. A 12.5 μm period mesh was used as a proximity mask for the atomic beam. The cesium atoms locally change the wetability of the SAM, which allows a wet etching reagent to remove the underlying gold in the exposed regions. An edge resolution of better than 100 nm was obtained. The experiment suggests that this method can either be used as a sensitive position detector with nanometer resolution in atom optics, or for nanostructuring in a resist technique.

  5. Demonstration of a cold atom beam splitter on atom chip

    NASA Astrophysics Data System (ADS)

    Jiang, Xiaojun; Li, Xiaolin; Zhang, Haichao; Wang, Yuzhu

    2016-08-01

    We report an experimental demonstration of a new scheme to split cold atoms on an atom chip. The atom chip consists of a U-wire and a Z-wire. The cold atom cloud is initially loaded and prepared in the Z-trap, which is split into two separate parts by switching on the current of the U-wire. The two separate atom clouds have a distance more than one millimeter apart from each other and show almost symmetrical profiles, corresponding to about a 50/50 splitting ratio. Project supported by the State Key Basic Research Program of China (Grant No. 2011CB921504) and the National Natural Science Foundation of China (Grant No. 91536107).

  6. Focused ion beam source method and apparatus

    DOEpatents

    Pellin, Michael J.; Lykke, Keith R.; Lill, Thorsten B.

    2000-01-01

    A focused ion beam having a cross section of submicron diameter, a high ion current, and a narrow energy range is generated from a target comprised of particle source material by laser ablation. The method involves directing a laser beam having a cross section of critical diameter onto the target, producing a cloud of laser ablated particles having unique characteristics, and extracting and focusing a charged particle beam from the laser ablated cloud. The method is especially suited for producing focused ion beams for semiconductor device analysis and modification.

  7. A sputtering derived atomic oxygen source for studying fast atom reactions

    NASA Technical Reports Server (NTRS)

    Ferrieri, Richard A.; Yung, Y. Chu; Wolf, Alfred P.

    1987-01-01

    A technique for the generation of fast atomic oxygen was developed. These atoms are created by ion beam sputtering from metal oxide surfaces. Mass resolved ion beams at energies up to 60 KeV are produced for this purpose using a 150 cm isotope separator. Studies have shown that particles sputtered with 40 KeV Ar(+) on Ta2O5 were dominantly neutral and exclusively atomic. The atomic oxygen also resided exclusively in its 3P ground state. The translational energy distribution for these atoms peaked at ca 7 eV (the metal-oxygen bond energy). Additional measurements on V2O5 yielded a bimodal distribution with the lower energy peak at ca 5 eV coinciding reasonably well with the metal-oxygen bond energy. The 7 eV source was used to investigate fast oxygen atom reactions with the 2-butene stereoisomers. Relative excitation functions for H-abstraction and pi-bond reaction were measured with trans-2-butene. The abstraction channel, although of minor relative importance at thermal energy, becomes comparable to the addition channel at 0.9 eV and dominates the high-energy regime. Structural effects on the specific channels were also found to be important at high energy.

  8. Progress in the MITICA beam source designa)

    NASA Astrophysics Data System (ADS)

    Zaccaria, P.; Agostinetti, P.; Marcuzzi, D.; Pavei, M.; Pilan, N.; Rizzolo, A.; Sonato, P.; Spada, F.; Trevisan, L.

    2012-02-01

    In the framework of the development of the ITER neutral beam (NB) system, a test facility is planned to be built in Padova. A full size prototype of the ITER heating NB injector (MITICA) shall be built and tested at full beam power (17 MW) as per ITER requirements. The design of the MITICA beam source has further progressed following updated optimization and overall integration criteria. In the paper, the major design choices and revisions are presented, together with some results of numerical analyses carried out in order to assess the electrostatic and thermo-mechanical behaviour of the source.

  9. Vacuum ultraviolet laser induced fluorescence on a Si atomic beam

    NASA Technical Reports Server (NTRS)

    O'Brian, T. R.; Lawler, J. E.

    1991-01-01

    A broadly applicable vacuum ultraviolet experiment is described for measuring radiative lifetimes of neutral and singly-ionized atoms in a beam environment to 5-percent accuracy using laser induced fluorescence. First results for neutral Si are reported.

  10. Advanced Light Source beam position monitor

    SciTech Connect

    Hinkson, J.

    1991-10-28

    The Advanced Light Source (ALS) is a synchrotron radiation facility nearing completion at LBL. As a third-generation machine, the ALS is designed to produce intense light from bend magnets, wigglers, and undulators (insertion devices). The facility will include a 50 MeV electron linear accelerator, a 1.5 GeV booster synchrotron, beam transport lines, a 1--2 GeV storage ring, insertion devices, and photon beam lines. Currently, the beam injection systems are being commissioned, and the storage ring is being installed. Electron beam position monitors (BPM) are installed throughout the accelerator and constitute the major part of accelerator beam diagnostics. The design of the BPM instruments is complete, and 50 units have been constructed for use in the injector systems. We are currently fabricating 100 additional instruments for the storage ring. In this paper I discuss engineering fabrication, testing and performance of the beam pickup electrodes and the BPM electronics.

  11. Atomic modeling of the plasma EUV sources

    NASA Astrophysics Data System (ADS)

    Sasaki, Akira; Sunahara, Atsushi; Furukawa, Hiroyuki; Nishihara, Katsunobu; Nishikawa, Takeshi; Koike, Fumihiro; Tanuma, Hajime

    2009-09-01

    We present the development of population kinetics models for tin plasmas that can be employed to design an EUV source for microlithography. The atomic kinetic code is constrained for the requirement that the model must be able to calculate spectral emissivity and opacity that can be used in radiation hydrodynamic simulations. Methods to develop compact and reliable atomic model with an appropriate set of atomic states are discussed. Specifically, after investigation of model dependencies and comparison experiment, we improve the effect of configuration interaction and the treatment of satellite lines. Using the present atomic model we discuss the temperature and density dependencies of the emissivity, as well as conditions necessary to obtain high efficiency EUV power at λ = 13.5 nm.

  12. Ion sources and targets for radioactive beams

    SciTech Connect

    Schiffer, J.P.; Back, B.B.; Ahmad, I.

    1995-08-01

    A high-intensity ISOL-type radioactive beam facility depends critically on the performance of the target/ion source system. We developed a concept for producing high-intensity secondary beams of fission fragments, such as {sup 132}Sn, using a two-part target and ion source combination. The idea involves stopping a 1000-kW beam of 200-MeV deuterons in a target of Be or U to produce a secondary beam of neutrons. Just behind the neutron production target is a second target, typically a porous form of UC, coupled to an ISOL-type ion source. In December 1994, we tested this concept with 200-MeV deuterons at low intensity in an experiment at the NSCL. The yields of characteristic gamma rays were measured and confirmed our predictions.

  13. Metastable atom probe for measuring electron beam density profiles

    NASA Technical Reports Server (NTRS)

    Lockhart, J. M.; Zorn, J. C.

    1972-01-01

    Metastable atom probe was developed for measuring current density in electron beam as function of two arbitrary coordinates, with spatial resolution better than 0.5 mm. Probe shows effects of space charge, magnetic fields, and other factors which influence electron current density, but operates with such low beam densities that introduced perturbation is very small.

  14. NOx reduction by electron beam-produced nitrogen atom injection

    DOEpatents

    Penetrante, Bernardino M.

    2002-01-01

    Deactivated atomic nitrogen generated by an electron beam from a gas stream containing more than 99% N.sub.2 is injected at low temperatures into an engine exhaust to reduce NOx emissions. High NOx reduction efficiency is achieved with compact electron beam devices without use of a catalyst.

  15. Beam current controller for laser ion source

    SciTech Connect

    Okamura, Masahiro

    2014-10-28

    The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

  16. Continuous loading of an atom beam into an optical lattice

    NASA Astrophysics Data System (ADS)

    Ivanov, Vladyslav V.

    I propose a method of deceleration and continuous loading of an atom beam into a far-off-resonance optical lattice. The loading of moving atoms into a conservative far-off-resonance potential requires the removal of the atom's excess kinetic energy. Here this is achieved by the Sisyphus cooling method, where a differential lattice-induced ac Stark shift is utilized. The proposed method is described for the case of ytterbium atoms. Numerical simulations demonstrate the possibility of reaching cold and dense samples in a continuous manner on the example of ytterbium atoms.

  17. Cascaded two-photon spectroscopy of Yb atoms with a transportable effusive atomic beam apparatus.

    PubMed

    Song, Minsoo; Yoon, Tai Hyun

    2013-02-01

    We present a transportable effusive atomic beam apparatus for cascaded two-photon spectroscopy of the dipole-forbidden transition (6s(2)(1)S0↔ 6s7s (1)S0) of Yb atoms. An ohmic-heating effusive oven is designed to have a reservoir volume of 1.6 cm(3) and a high degree of atomic beam collimation angle of 30 mrad. The new atomic beam apparatus allows us to detect the spontaneously cascaded two-photons from the 6s7s(1)S0 state via the intercombination 6s6p(3)P1 state with a high signal-to-noise ratio even at the temperature of 340 °C. This is made possible in our apparatus because of the enhanced atomic beam flux and superior detection solid angle. PMID:23464193

  18. Slowing and Stopping Supersonic Beams with an Atomic Coilgun

    NASA Astrophysics Data System (ADS)

    Libson, Adam; Narevicius, Edvardas; Parthey, Christian G.; Chavez, Isaac; Narevicius, Julia; Even, Uzi; Raizen, Mark G.

    2008-05-01

    We report the stopping of a supersonic beam of metastable neon using an atomic coilgun. The coilgun relies on the Zeeman effect, and uses pulsed magnetic fields of up to 5.2 T to bring atoms from 446 m/s to near rest. Additionally, we have implemented the coilgun to slow a supersonic beam of molecular oxygen from 458 m/s to 238 m/s. This method can be applied to stop and trap any paramagnetic atom or molecule. Future applications will be discussed.

  19. Phase conjugation of a quantum-degenerate atomic fermion beam.

    PubMed

    Search, Chris P; Meystre, Pierre

    2003-09-01

    We discuss the possibility of phase conjugation of an atomic Fermi field via nonlinear wave mixing in an ultracold gas. It is shown that for a beam of fermions incident on an atomic phase-conjugate mirror, a time-reversed backward propagating fermionic beam is generated similar to the case in nonlinear optics. By adopting an operational definition of the phase, we show that it is possible to infer the presence of the phase-conjugate field by the loss of the interference pattern in an atomic interferometer. PMID:14525466

  20. Transverse laser cooling of a thermal atomic beam of dysprosium

    SciTech Connect

    Leefer, N.; Cingoez, A.; Gerber-Siff, B.; Sharma, Arijit; Torgerson, J. R.; Budker, D.

    2010-04-15

    A thermal atomic beam of dysprosium atoms is cooled using the 4f{sup 10}6s{sup 2}(J=8){yields}4f{sup 10}6s6p(J=9) transition at 421 nm. The cooling is done via a standing light wave orthogonal to the atomic beam. Efficient transverse cooling to the Doppler limit is demonstrated for all observable isotopes of dysprosium. Branching ratios to metastable states are demonstrated to be <5x10{sup -4}. A scheme for enhancement of the nonzero-nuclear-spin-isotope cooling and a method for direct identification of possible trap states are proposed.

  1. Ion and atomic beams for controlled thermonuclear fusion and technological applications

    NASA Astrophysics Data System (ADS)

    Gabovich, Mark Davydovich; Pleshivtsev, Nikolai Vasil'evich; Semashko, Nikolai Nikolaevich

    The physical principles of the generation, focusing, and transporting of heavy-current ion and atomic beams are examined, with attention given to plasma sources of hydrogen, deuterium, inert gas, and refractory metal ions. The main characteristics of ion sputtering are discussed, as are various industrial applications of ion beams, such as surface cleaning, ion-beam machining, grinding, etching, and deposition of ion-sputtered coatings. Also discussed are the possibilities of improving the physicochemical and mechanical properties of steels through ion alloying, ion-beam microanalysis of surfaces, and production of complex profiles of submicron size.

  2. A high-flux BEC source for mobile atom interferometers

    NASA Astrophysics Data System (ADS)

    Rudolph, Jan; Herr, Waldemar; Grzeschik, Christoph; Sternke, Tammo; Grote, Alexander; Popp, Manuel; Becker, Dennis; Müntinga, Hauke; Ahlers, Holger; Peters, Achim; Lämmerzahl, Claus; Sengstock, Klaus; Gaaloul, Naceur; Ertmer, Wolfgang; Rasel, Ernst M.

    2015-06-01

    Quantum sensors based on coherent matter-waves are precise measurement devices whose ultimate accuracy is achieved with Bose-Einstein condensates (BECs) in extended free fall. This is ideally realized in microgravity environments such as drop towers, ballistic rockets and space platforms. However, the transition from lab-based BEC machines to robust and mobile sources with comparable performance is a challenging endeavor. Here we report on the realization of a miniaturized setup, generating a flux of 4× {{10}5} quantum degenerate 87Rb atoms every 1.6 s. Ensembles of 1× {{10}5} atoms can be produced at a 1 Hz rate. This is achieved by loading a cold atomic beam directly into a multi-layer atom chip that is designed for efficient transfer from laser-cooled to magnetically trapped clouds. The attained flux of degenerate atoms is on par with current lab-based BEC experiments while offering significantly higher repetition rates. Additionally, the flux is approaching those of current interferometers employing Raman-type velocity selection of laser-cooled atoms. The compact and robust design allows for mobile operation in a variety of demanding environments and paves the way for transportable high-precision quantum sensors.

  3. Positronium beam scattering from atoms and molecules

    NASA Astrophysics Data System (ADS)

    Garner, A. J.; Özen, A.; Laricchia, G.

    1998-08-01

    Production techniques and applications of positronium beams in the energy range ˜10-100 eV are reviewed. Recent positronium-gas cross-section results for He, Ar, H 2 and O 2 measured at UCL are discussed and compared to theoretical calculations and other relevant experimental data.

  4. Pseudo ribbon metal ion beam source

    SciTech Connect

    Stepanov, Igor B. Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-02-15

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  5. Research in atomic and applied physics using a 6-GeV synchrotron source

    SciTech Connect

    Jones, K.W.

    1985-12-01

    The Division of Atomic and Applied Physics in the Department of Applied Science at Brookhaven National Laboratory conducts a broad program of research using ion beams and synchrotron radiation for experiments in atomic physics and nuclear analytical techniques and applications. Many of the experiments would benefit greatly from the use of high energy, high intensity photon beams from a 6-GeV synchrotron source. A survey of some of the specific scientific possibilities is presented.

  6. Neutral beam source commercialization study. Final report

    SciTech Connect

    King, H.J.

    1980-06-01

    The basic tasks of this Phase II project were to: generate a set of design drawings suitable for quantity production of sources of this design; fabricate a functional neutral beam source incorporating as many of the proposed design changes as proved feasible; and document the procedures and findings developed during the contract. These tasks have been accomplished and represent a demonstrated milestone in the industrialization of this complete device.

  7. Laser-induced fluorescence of metal-atom impurities in a neutral beam

    SciTech Connect

    Burrell, C.F.; Pyle, R.V.; Sabetimani, Z.; Schlachter, A.S.

    1984-10-01

    The need to limit impurities in fusion devices to low levels is well known. We have investigated, by the technique of laser-induced fluorescence, the concentration of heavy-metal atoms in a neutral beam caused by their evaporation from the hot filaments in a conventional high-current multifilament hydrogen-ion source.

  8. Resonant Ionization Laser Ion Source for Radioactive Ion Beams

    SciTech Connect

    Liu, Yuan; Beene, James R; Havener, Charles C; Vane, C Randy; Gottwald, T.; Wendt, K.; Mattolat, C.; Lassen, J.

    2009-01-01

    A resonant ionization laser ion source based on all-solid-state, tunable Ti:Sapphire lasers is being developed for the production of pure radioactive ion beams. It consists of a hot-cavity ion source and three pulsed Ti:Sapphire lasers operating at a 10 kHz pulse repetition rate. Spectroscopic studies are being conducted to develop ionization schemes that lead to ionizing an excited atom through an auto-ionization or a Rydberg state for numerous elements of interest. Three-photon resonant ionization of 12 elements has been recently demonstrated. The overall efficiency of the laser ion source measured for some of these elements ranges from 1 to 40%. The results indicate that Ti:Sapphire lasers could be well suited for laser ion source applications. The time structures of the ions produced by the pulsed lasers are investigated. The information may help to improve the laser ion source performance.

  9. Etching Semiconductors With Beams Of Reactive Atoms

    NASA Technical Reports Server (NTRS)

    Minton, Timothy K.; Giapis, Konstantinos P.; Moore, Teresa A.

    1995-01-01

    Method of etching semiconductors with energetic beams of electrically neutral, but chemically reactive, species undergoing development. Enables etching of straight walls into semiconductor substrates at edges of masks without damage to underlying semiconductor material. In addition to elimination of charge damage, technique reduces substrate bombardment damage because translational energy of neutral species in range 2-12 eV, below damage threshold of many semiconductor materials. Furthermore, low-energy neutrals cause no mask erosion allowing for etching features with very high aspect ratios.

  10. Molecular beam studies of hot atom chemical reactions: Reactive scattering of energetic deuterium atoms

    SciTech Connect

    Continetti, R.E.; Balko, B.A.; Lee, Y.T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H/sub 2/ /minus/> DH + H and the substitution reaction D + C/sub 2/H/sub 2/ /minus/> C/sub 2/HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible. 18 refs., 9 figs.

  11. Molecular Beam Studies of Hot Atom Chemical Reactions: Reactive Scattering of Energetic Deuterium Atoms

    DOE R&D Accomplishments Database

    Continetti, R. E.; Balko, B. A.; Lee, Y. T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H{sub 2} -> DH + H and the substitution reaction D + C{sub 2}H{sub 2} -> C{sub 2}HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible.

  12. A compact source for bunches of singly charged atomic ions

    NASA Astrophysics Data System (ADS)

    Murböck, T.; Schmidt, S.; Andelkovic, Z.; Birkl, G.; Nörtershäuser, W.; Vogel, M.

    2016-04-01

    We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 106 Mg+ ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg+ ions for sympathetic cooling of highly charged ions by laser-cooled 24Mg+.

  13. Electron-beam multicharge ion source IMI-2

    NASA Astrophysics Data System (ADS)

    Abdul'manov, V. G.; Dement'ev, E. N.; Miginskaya, E. G.; Mironenko, L. A.; Pirogov, O. V.; Tomilov, V. P.; Tsukanov, V. M.

    2000-08-01

    The main parameters of the electron beam multicharge ion source IMI-2 are given. Experimental results are also given. The IMI-2 electron-beam system (EBS) includes a short-focus electron gyn with a spherical cathode of diameter 16 mm and curvature radius of 9.5 mm. The perveance of the gun is 1,6 (mu) A/V3/2. The electron beam current can reach 2.5 A. An electrostatic and magnetic beam compression of ~103 allows one to obtain a density of the electron beam of not less than ~103 A/cm2 on a 30 cm length. A specific method of dosed injection of the atoms of solid-state elements to an ion trap by means of local pulse deflection of the electron beam was used in the facility 1. The electron-beam ion source (EBIS) IMI-2, Fig. 1, has a vertical design with an electron gun in the top section. The electron gun is mounted in a vacuum chamber of diameter 160 mm and length 500 mm. The vacuum chamber having a drift structure is inside the classical water-cooled solenoid with a completely closed magnetic circuit. An electron collector, an ion line, and a magnetic analyzer are located in the lower section of the facility. Like IMI-1 7-9, IMI-2 2-6 was also designed at the Budker Institute of Nuclear Physics for production of multicharge beams of gaseous and solid elements. In the EBS parameters, IMI-2 is intermediate between first-generation EBIS and those that can be used at acceleration complexes developed at the present time.

  14. Evaporation of an atomic beam on a material surface

    SciTech Connect

    Reinaudi, G.; Lahaye, T.; Couvert, A.; Wang, Z.; Guery-Odelin, D.

    2006-03-15

    We report on the implementation of evaporative cooling of a magnetically guided beam by adsorption on a ceramic surface. We use a transverse magnetic field to shift locally the beam towards the surface, where atoms are selectively evaporated. With a 5-mm-long ceramic piece, we gain a factor of 1.5{+-}0.2 on the phase-space density. Our results are consistent with a 100% efficiency of this evaporation process. The flexible implementation that we have demonstrated, combined with the very local action of the evaporation zone, makes this method particularly suited for the evaporative cooling of a beam.

  15. Plasma heating with multi-MeV neutral atom beams

    SciTech Connect

    Grisham, L.R.; Post, D.E.; Mikkelsen, D.R.; Eubank, H.P.

    1981-10-01

    We explore the utility and feasibility of neutral beams of greater than or equal to 6 AMU formed from negative ions, and also of D/sup 0/ formed from D/sup -/. The negative ions would be accelerated to approx. 1 to 2 MeV/AMU and neutralized, whereupon the neutral atoms would be used to heat and, perhaps, to drive current in magnetically confined plasmas. Such beams appear feasible and offer the promise of significant advantages relative to conventional neutral beams based on positive deuterium ions at approx. 150 keV.

  16. Application of an atomic oxygen beam facility to the investigation of shuttle glow chemistry

    NASA Technical Reports Server (NTRS)

    Arnold, G. S.; Peplinski, D. R.

    1985-01-01

    A facility for the investigation of the interactions of energetic atomic oxygen with solids is described. The facility is comprised of a four chambered, differentially pumped molecular beam apparatus which can be equipped with one of a variety of sources of atomic oxygen. The primary source is a dc arc heated supersonic nozzle source which produces a flux of atomic oxygen in excess of 10 to the 15th power sq cm/sec at the target, at a velocity of 3.5 km/sec. Results of applications of this facility to the study of the reactions of atomic oxygen with carbon and polyimide films are briefly reviewed and compared to data obtained on various flights of the space shuttle. A brief discussion of possible application of this facility to investigation of chemical reactions which might contribute to atmosphere induced vehicle glow is presented.

  17. SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.

    SciTech Connect

    KESSELMAN,M.; DAWSON,W.C.

    2002-05-06

    This paper will discuss the present electronics design for the beam current monitor system to be used throughout the Spallation Neutron Source (SNS) under construction at Oak Ridge National Laboratory. The beam is composed of a micro-pulse structure due to the 402.5MHz RF, and is chopped into mini-pulses of 645ns duration with a 300ns gap, providing a macro-pulse of 1060 mini-pulses repeating at a 60Hz rate. Ring beam current will vary from about 15ma peak during studies, to about 50Amps peak (design to 100 amps). A digital approach to droop compensation has been implemented and initial test results presented.

  18. Guiding cold atoms in a hollow laser beam

    NASA Astrophysics Data System (ADS)

    Xu, Xinye; Minogin, V. G.; Lee, Kwanil; Wang, Yuzhu; Jhe, Wonho

    1999-12-01

    The theory of atom guiding in a far blue-detuned hollow laser beam (HLB) is developed for the dipole interaction scheme described by a three-level Λ model. The complete kinetic description of atomic motion based on the Fokker-Planck equation for the atomic distribution function is presented. The dipole gradient force, radiation pressure force, and momentum diffusion tensor are then derived. It is found that even for a far-detuned laser beam, the optical potential for a three-level Λ atom is not generally reduced to a sum of two independent potentials associated with the two two-level interactions in the Λ scheme. The theory developed here is also compared with the experimental guiding of cold 85Rb atoms in the HLB. The experimental results are found to be in good agreement with the Monte Carlo simulations based on the three-level Λ model. We observe that the guiding efficiency depends strongly on the intensity and the detuning of the HLB and the initial temperature of atoms. In particular, the experimental results show that, at small detunings, the guiding efficiency is deteriorated strongly by the radiation pressure force. The Monte Carlo simulations also indicate that the efficiency of guiding versus detuning depends strongly on the direction of the HLB propagation with respect to that of atomic motion. Under optimal conditions, the guiding efficiency was found to be about 20%.

  19. Neutral Atom Lithography Using a Bright Metastable Helium Beam

    NASA Astrophysics Data System (ADS)

    Allred, Claire; Reeves, Jason; Corder, Chris; Metcalf, Harold

    2009-05-01

    We have performed neutral atom lithography using a bright beam of metastable 2^3S1 Helium (He*) that is collimated with the bichromatic force, followed by three optical molasses velocity compression stages. Because bichromatic collimation makes such an intense He* beam, our exposure time is measured in minutes instead of hours. We have exploited the focusing and channeling of the He* beam into lines by the dipole force the atoms experience while traversing a standing wave of λ = 1083 nm light tuned 500 MHz below the 2^3S1-> 2^3P2 transition. Focused He* atoms damage the molecules of a self assembled monolayer (SAM) of nonanethiol by depositing their 20 eV of internal energy on its surface. The undisturbed SAM then protects a 200 å,ayer of gold that has been evaporated onto a prepared Silicon wafer from a wet chemical etch. Samples created with this method have an edge resolution of 63 nm that was observed using an atomic force microscope. The lines are separated by λ/2 and cover the entire exposed length of the substrate, about 3 mm. They are about 3 mm long, corresponding to about twice the beam waist of the laser standing wave. Thus there are ˜6 x10^3 lines of length ˜1500 λ. These results agree with our numerical simulations of the experiment.

  20. Production of pulsed atomic oxygen beams via laser vaporization methods

    NASA Technical Reports Server (NTRS)

    Brinza, David E.; Coulter, Daniel R.; Liang, Ranty H.; Gupta, Amitava

    1987-01-01

    Energetic pulsed atomic oxygen beams were generated by laser-driven evaporation of cryogenically frozen ozone/oxygen films and thin films of indium-tin oxide (ITO). Mass and energy characterization of beams from the ozone/oxygen films were carried out by mass spectrometry. The peak flux, found to occur at 10 eV, is estimated from this data to be 3 x 10(20) m(-2) s(-1). Analysis of the time-of-flight data indicates a number of processes contribute to the formation of the atomic oxygen beam. The absence of metastable states such as the 2p(3) 3s(1) (5S) level of atomic oxygen blown off from ITO films is supported by the failure to observe emission at 777.3 nm from the 2p(3) 3p(1) (5P sub J) levels. Reactive scattering experiments with polymer film targets for atomic oxygen bombardment are planned using a universal crossed molecular beam apparatus.

  1. Production of pulsed atomic oxygen beams via laser vaporization methods

    NASA Technical Reports Server (NTRS)

    Brinza, David E.; Coulter, Daniel R.; Liang, Ranty H.; Gupta, Amitava

    1986-01-01

    The generation of energetic pulsed atomic oxygen beams by laser-driven evaporation of cryogenically frozen ozone/oxygen films and thin indium-tin oxide (ITO) films is reported. Mass spectroscopy is used in the mass and energy characterization of beams from the ozone/oxygen films, and a peak flux of 3 x 10 to the 20th/sq m per sec at 10 eV is found. Analysis of the time-of-flight data suggests that several processes contribute to the formation of the oxygen beam. Results show the absence of metastable states such as the 2p(3)3s(1)(5S) level of atomic oxygen blown-off from the ITO films. The present process has application to the study of the oxygen degradation problem of LEO materials.

  2. Neutral atomic oxygen beam produced by ion charge exchange for Low Earth Orbital (LEO) simulation

    NASA Technical Reports Server (NTRS)

    Banks, Bruce; Rutledge, Sharon; Brdar, Marko; Olen, Carl; Stidham, Curt

    1987-01-01

    A low energy neutral atomic oxygen beam system was designed and is currently being assembled at the Lewis Research Center. The system utilizes a 15 cm diameter Kaufman ion source to produce positive oxygen ions which are charge exchange neutralized to produce low energy (variable from 5 to 150 eV) oxygen atoms at a flux simulating real time low Earth orbital conditions. An electromagnet is used to direct only the singly charged oxygen ions from the ion source into the charge exchange cell. A retarding potential grid is used to slow down the oxygen ions to desired energies prior to their charge exchange. Cryogenically cooled diatomic oxygen gas in the charge exchange cell is then used to transfer charge to the oxygen ions to produce a neutral atomic oxygen beam. Remaining non-charge exchanged oxygen ions are then swept from the beam by electromagnetic or electrostatic deflection depending upon the desired experiment configuration. The resulting neutral oxygen beam of 5 to 10 cm in diameter impinges upon target materials within a sample holder fixture that can also provide for simultaneous heating and UV exposure during the atomic oxygen bombardment.

  3. Photoionization research on atomic beams. 2: The photoionization cross section of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Comes, F. J.; Speier, F.; Elzer, A.

    1982-01-01

    An experiment to determine the absolute value of the photo-ionization cross section of atomic oxygen is described. The atoms are produced in an electrical discharge in oxygen gas with 1% hydrogen added. In order to prevent recombination a crossed beam technique is employed. The ions formed are detected by a time-of-flight mass spectrometer. The concentration of oxygen atoms in the beam is 57%. The measured photoionization cross section of atomic oxygen is compared with theoretical data. The results show the participation of autoionization processes in ionization. The cross section at the autoionizing levels detected is considerably higher than the absorption due to the unperturbed continuum. Except for wavelengths where autoionization occurs, the measured ionization cross section is in fair agreement with theory. This holds up to 550 A whereas for shorter wavelengths the theoretical values are much higher.

  4. Atomic Beam Scattering Methods to Study Overlayer Structures and H-Surface Interaction Relevant to Astrophysics

    NASA Astrophysics Data System (ADS)

    Lin, Jingsu

    In this thesis we present results of experimental methods for studying surface structures of ultra-thin films and describe a new apparatus to study the recombination of atomic hydrogen on well characterized low temperature surface using atomic and molecular beam methods. We have used atomic beam scattering (ABS) to characterize the growth of mercury and lead overlayers on Cu(001) surface. The structures of ordered phases have been identified using ABS and low-energy electron diffraction (LEED). A model to analyze diffraction data from these phases is presented. The new apparatus we are going to describe includes a high performance atomic hydrogen source using radio-frequency (RF) dissociation. The dissociation efficiency can be as high as 90% in the optimized pressure range. An atomic hydrogen beam line has been added to our ultra-high vacuum (UHV) scattering apparatus. We have also designed and constructed a low temperature sample manipulator for experiments at liquid helium temperatures. The manipulator has one degree of freedom of rotation and the capability of heating the sample to 700K and cooling down to 12K. The first sample studied was a single graphite surface. We have used a He beam to characterize the sample surface and to monitor deposition of H on the sample surface in real time. A series of "adsorption curves" have been obtained at different temperature and doses. We found that at temperatures below 16K, both H and H_2 have formed a partial layer on the surface. From adsorption curve, we deduce that the initial sticking coefficient for H is about 0.06 when surface at 16K. When the H beam is interrupted, the He specularly reflected beam recovers partially, indicating that hydrogen atoms desorb, while others remain on the surface. The residual coverage of H is estimated to be about 2% of a monolayer.

  5. Neutral Atom Lithography Using a Bright Metastable Helium Beam

    NASA Astrophysics Data System (ADS)

    Shean, Claire; Reeves, Jason; Metcalf, Harold

    2008-05-01

    We have performed neutral atom lithography using a bright beam of metastable Helium (He*) that is collimated with the bichromatic force followed by two Doppler molasses velocity compression stages. We have previously demonstrated this lithography method using a metal grid to project its image on a self assembled monolayer (SAM) of nonanethiol. The open areas of the grid allow incident He* to damage the SAM molecules by depositing their 20 eV of internal energy on the surface. The undisturbed SAM regions then protect a gold coated Silicon wafer from a wet chemical etch. Samples created with this method have an edge resolution of 63 nm that was observed using an atomic force microscope. We have now achieved focusing of the He* beam into lines by the dipole force that the atoms experience while traversing a standing wave of λ = 1083 nm light tuned 500 MHz above the 2^3S1-->2^3P2 transition. The lines are separated by λ/2 and their length is comparable to the laser beam waist. Because bichromatic collimation makes such an intense He* beam, our exposure time can be as short as 10 minutes.

  6. SLC polarized beam source electron optics design

    SciTech Connect

    Eppley, K.R.; Lavine, T.L.; Early, R.A.; Herrmannsfeldt, W.B.; Miller, R.H.; Schultz, D.C.; Spencer, C.M.; Yeremian, A.D.

    1991-05-01

    This paper describes the design of the beam-line from the polarized electron gun to the linac injector in the Stanford Linear Collider (SLC). The polarized electron source is a GaAs photocathode, requiring 10{sup {minus}11}-Torr-range pressure for adequate quantum efficiency and longevity. The photocathode is illuminated by 3-nsec-long laser pulses. The quality of the optics for the 160-kV beam is crucial since electron-stimulated gas desorption from beam loss in excess of 0.1% of the 20-nC pulses may poison the photocathode. Our design for the transport line consists of a differential pumping region isolated by a pair of valves. Focusing is provided by a pair of Helmholtz coils and by several iron-encased solenoidal lenses. Our optics design is based on beam transport simulations using 2{1/2}-D particle-in-cell codes to model the gun and to solve the fully-relativistic time-dependent equations of motion in three dimensions for electrons in the presence of azimuthally symmetric electromagnetic fields. 6 refs., 6 figs.

  7. LASER COOLING: Cold atomic beams of high brightness

    NASA Astrophysics Data System (ADS)

    Rozhdestvensky, Yu V.

    2004-11-01

    The possibility is studied for obtaining intense cold atomic beams by using the Renyi entropy to optimise the laser cooling process. It is shown in the case of a Gaussian velocity distribution of atoms, the Renyi entropy coincides with the density of particles in the phase space. The optimisation procedure for cooling atoms by resonance optical radiation is described, which is based on the thermodynamic law of increasing the Renyi entropy in time. Our method is compared with the known methods for increasing the laser cooling efficiency such as the tuning of a laser frequency in time and a change of the atomic transition frequency in an inhomogeneous transverse field of a magnetic solenoid.

  8. Hyperthermal atomic oxygen source for near-space simulation experiments

    SciTech Connect

    Dodd, James A.; Baker, Paul M.; Hwang, Eunsook S.; Sporleder, David; Stearns, Jaime A.; Chambreau, Steven D.; Braunstein, Matthew; Conforti, Patrick F.

    2009-09-15

    A hyperthermal atomic oxygen (AO) beam facility has been developed to investigate the collisions of high-velocity AO atoms with vapor-phase counterflow. Application of 4.5 kW, 2.4 GHz microwave power in the source chamber creates a continuous discharge in flowing O{sub 2} gas. The O{sub 2} feedstock is introduced into the source chamber in a vortex flow to constrain the plasma to the center region, with the chamber geometry promoting resonant excitation of the TM{sub 011} mode to localize the energy deposition in the vicinity of the aluminum nitride (AlN) expansion nozzle. The approximately 3500 K environment serves to dissociate the O{sub 2}, resulting in an effluent consisting of 40% AO by number density. Downstream of the nozzle, a silicon carbide (SiC) skimmer selects the center portion of the discharge effluent, prior to the expansion reaching the first shock front and rethermalizing, creating a beam with a derived 2.5 km s{sup -1} velocity. Differential pumping of the skimmer chamber, an optional intermediate chamber and reaction chamber maintains a reaction chamber pressure in the mid-10{sup -6} to mid-10{sup -5} Torr range. The beam has been characterized with regard to total AO beam flux, O{sub 2} dissociation fraction, and AO spatial profile using time-of-flight mass spectrometric and Kapton-H erosion measurements. A series of reactions AO+C{sub n}H{sub 2n} (n=2-4) has been studied under single-collision conditions using mass spectrometric product detection, and at higher background pressure detecting dispersed IR emissions from primary and secondary products using a step-scan Michelson interferometer. In a more recent AO crossed-beam experiment, number densities and predicted IR emission intensities have been modeled using the direct simulation Monte Carlo technique. The results have been used to guide the experimental conditions. IR emission intensity predictions are compared to detected signal levels to estimate absolute reaction cross sections.

  9. Hyperthermal atomic oxygen source for near-space simulation experiments.

    PubMed

    Dodd, James A; Baker, Paul M; Hwang, Eunsook S; Sporleder, David; Stearns, Jaime A; Chambreau, Steven D; Braunstein, Matthew; Conforti, Patrick F

    2009-09-01

    A hyperthermal atomic oxygen (AO) beam facility has been developed to investigate the collisions of high-velocity AO atoms with vapor-phase counterflow. Application of 4.5 kW, 2.4 GHz microwave power in the source chamber creates a continuous discharge in flowing O(2) gas. The O(2) feedstock is introduced into the source chamber in a vortex flow to constrain the plasma to the center region, with the chamber geometry promoting resonant excitation of the TM(011) mode to localize the energy deposition in the vicinity of the aluminum nitride (AlN) expansion nozzle. The approximately 3500 K environment serves to dissociate the O(2), resulting in an effluent consisting of 40% AO by number density. Downstream of the nozzle, a silicon carbide (SiC) skimmer selects the center portion of the discharge effluent, prior to the expansion reaching the first shock front and rethermalizing, creating a beam with a derived 2.5 km s(-1) velocity. Differential pumping of the skimmer chamber, an optional intermediate chamber and reaction chamber maintains a reaction chamber pressure in the mid-10(-6) to mid-10(-5) Torr range. The beam has been characterized with regard to total AO beam flux, O(2) dissociation fraction, and AO spatial profile using time-of-flight mass spectrometric and Kapton-H erosion measurements. A series of reactions AO+C(n)H(2n) (n=2-4) has been studied under single-collision conditions using mass spectrometric product detection, and at higher background pressure detecting dispersed IR emissions from primary and secondary products using a step-scan Michelson interferometer. In a more recent AO crossed-beam experiment, number densities and predicted IR emission intensities have been modeled using the direct simulation Monte Carlo technique. The results have been used to guide the experimental conditions. IR emission intensity predictions are compared to detected signal levels to estimate absolute reaction cross sections. PMID:19791929

  10. MULTIPLE ELECTRON BEAM ION PUMP AND SOURCE

    DOEpatents

    Ellis, R.E.

    1962-02-27

    A vacuum pump is designed which operates by ionizing incoming air and by withdrawing the ions from the system by means of electrical fields. The apparatus comprises a cylindrical housing communicable with the vessel to be evacuated and having a thin wall section in one end. Suitable coils provide a longitudinal magnetic field within the cylinder. A broad cathode and an anode structure is provided to establish a plurality of adjacent electron beams which are parallel to the cylinder axis. Electron reflector means are provided so that each of the beams constitutes a PIG or reflex discharge. Such structure provides a large region in which incoming gas molecules may be ionized by electron bombardment. A charged electrode assembly accelerates the ions through the thin window, thereby removing the gas from the system. The invention may also be utilized as a highly efficient ion source. (AEC)

  11. High-resolution spectral analysis of light from neutral beams and ion source plasmas

    SciTech Connect

    McNeill, D H; Kim, J

    1980-05-01

    The spectral distributions of Balmer alpha emission from 7- and 22-cm-diam neutral hydrogen beams have been measured with a Fabry-Perot interferometer to obtain information on the beam energy, divergence, and species composition. Results of these measurements are compared with other data on the beam properties to evaluate high-resolution spectroscopy as a beam diagnostic technique. Measurements on ion source plasmas and on beam-produced background plasmas yield average neutral atom energies of approximately 0.3 and 2.5 eV, respectively.

  12. Kinetics of the evaporative cooling of an atomic beam

    SciTech Connect

    Lahaye, Thierry; Guery-Odelin, David

    2006-06-15

    We compare two distinct models of evaporative cooling of a magnetically guided atomic beam: a continuous one, consisting in approximating the atomic distribution function by a truncated equilibrium distribution, and a discrete-step one, in which the evaporation process is described in terms of successive steps consisting in a truncation of the distribution followed by rethermalization. Calculations are performed for the semilinear potential relevant for experiments. We show that it is possible to map one model onto the other, allowing us to infer, for the discrete-step model, the rethermalization kinetics, which turns out to be strongly dependent upon the shape of the confining potential.

  13. Cold-atom dynamics in crossed-laser-beam waveguides

    SciTech Connect

    Torrontegui, E.; Muga, J. G.; Echanobe, J.; Ruschhaupt, A.; Guery-Odelin, D.

    2010-10-15

    We study the dynamics of neutral cold atoms in an L-shaped crossed-beam optical waveguide formed by two perpendicular red-detuned lasers of different intensities and a blue-detuned laser at the corner. The motion in one sense is optimized, and the motion in the other sense may be suppressed even if it is energetically allowed. Quantum and classical simulations are performed and give similar results. Complemented with a vibrational cooling process we find a range of parameters for which this setting works as a one-way device or 'atom diode'.

  14. Optical beam deflection noncontact atomic force microscope optimized with three-dimensional beam adjustment mechanism

    NASA Astrophysics Data System (ADS)

    Yokoyama, Kousuke; Ochi, Taketoshi; Uchihashi, Takayuki; Ashino, Makoto; Sugawara, Yasuhiro; Suehira, Nobuhito; Morita, Seizo

    2000-01-01

    We present a design and performance of an optical beam deflection noncontact atomic force microscope (nc-AFM). The optical deflection detection system can be optimized by the three-dimensional beam position adjustment mechanism (the slider which mounts laser diode module, the spherical rotors with mirror and the cylinder which mounts quadrant photodiode) using inertial stepping motors in an ultrahigh vacuum (UHV). The samples and cantilevers are easily exchanged in UHV. The performance of the instrument is demonstrated with the atomically resolved nc-AFM images for various surfaces such as Si(111)7×7, Cu(111), TiO2(110), and thymine/highly oriented pyrolytic graphite.

  15. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, David G.

    1993-01-01

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  16. Particle beam generator using a radioactive source

    DOEpatents

    Underwood, D.G.

    1993-03-30

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  17. Acoustic source for generating an acoustic beam

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian

    2016-05-31

    An acoustic source for generating an acoustic beam includes a housing; a plurality of spaced apart piezo-electric layers disposed within the housing; and a non-linear medium filling between the plurality of layers. Each of the plurality of piezoelectric layers is configured to generate an acoustic wave. The non-linear medium and the plurality of piezo-electric material layers have a matching impedance so as to enhance a transmission of the acoustic wave generated by each of plurality of layers through the remaining plurality of layers.

  18. Spallation neutron source beam loss monitor system

    NASA Astrophysics Data System (ADS)

    Gassner, D.; Witkover, R.; Cameron, P.; Power, J.

    2000-11-01

    The Spallation Neutron Source facility to be built at ORNL is designed to accumulate 2×1014 protons at 1.0 GeV and deliver them to the experimental target in one bunch at 60 Hz. To achieve this goal and protect the machine from excessive radiation activation, an uncontrolled loss criteria of 1 part in 104 (1 W/m) has been specified. Measured losses will be conditioned to provide machine tuning data, a beam abort trigger, and logging of loss history. The design of the distributed loss monitor system utilizing argon-filled glass ionization chambers and scintillator-photomultipliers will be presented.

  19. Neutral atom beam technique enhances bioactivity of PEEK

    NASA Astrophysics Data System (ADS)

    Khoury, Joseph; Kirkpatrick, Sean R.; Maxwell, Melissa; Cherian, Raymond E.; Kirkpatrick, Allen; Svrluga, Richard C.

    2013-07-01

    Polyetheretherketone (PEEK) is currently gaining popularity in orthopedic and spinal applications but has potential drawbacks in use. PEEK is biocompatible, similar in elasticity to bone, and radiolucent; however, it has been shown to be inert and does not integrate well with bone. Recent efforts have focused on increasing the bioactivity of PEEK by modifying the surface to improve the bone-implant interface. We have employed a novel Accelerated Neutral Atom Beam technique (ANAB) to enhance the bioactivity of PEEK. ANAB employs an intense beam of cluster-like packets of accelerated unbonded neutral argon (Ar) gas atoms. These beams are created by first producing a highly energetic Gas Cluster Ion Beam (GCIB) comprised of van der Waals bonded Ar atoms, then transferring energy to the clusters so as to cause release of most of the interatomic bonds, and finally deflecting away the remaining electrically charged cluster cores of still bonded atoms. We identified that ANAB treatment of PEEK results in nanometer scale surface modifications as well as increased surface hydrophilicity. Human osteoblasts seeded onto the surface of ANAB-treated PEEK exhibited enhanced growth as compared to control PEEK as evidenced by cell proliferation assays and microscopy. This increase in bioactivity resulted in cell proliferation levels comparable to native titanium. An in vivo study using a rat calvarial critical size defect model revealed enhanced osseointegration where bone tissue formation was evident only on the ANAB treated PEEK. Taken together, these data suggest that ANAB treatment of PEEK has the potential to enhance its bioactivity, resulting in bone formation and significantly decreasing osseointegration time of orthopedic and spinal implants.

  20. X-ray spectra from the Cornell Electron-Beam Ion Source (CEBIS I)

    SciTech Connect

    Johnson, B.M.; Jones, K.W.; Kostroun, V.O.; Ghanbari, E.; Janson, S.W.

    1985-01-01

    Radiation emitted from the Cornell electron beam ion source (CEBIS I) has been surveyed with a Si(Li) x-ray detector. These spectra can be used to estimate backgrounds from electron bremsstrahlung and to evaluate the feasibility of atomic physics experiments using the CEBIS I source in this configuration. 1 ref., 2 figs.

  1. Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

    2010-01-01

    Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

  2. A source of translationally cold molecular beams

    NASA Astrophysics Data System (ADS)

    Sarkozy, Laszlo C.

    Currently the fields studying or using molecules with low kinetic energies are experiencing an unprecedented growth. Astronomers and chemists are interested in chemical reactions taking place at temperatures below or around 20 K, spectroscopists could make very precise measurements on slow molecules and molecular physicists could chart the potential energy surfaces more accurately. And the list continues. All of these experiments need slow molecules, with kinetic energies from around 10 cm-1 down to 0. Several designs of cold sources have already been made. The most interesting ones are presented. This work describes the design and the testing of a cold source based on the collisional cooling technique: the molecules of interest are cooled well below their freezing point by a precooled buffer gas. This way condensation is avoided. The source is a copper cell cooled to 4.2 K by an external liquid helium bath. The cell is filled with cold buffer gas (helium). The molecules of choice (ammonia) are injected through a narrow tube in the middle of the cell. The cold molecules leave the cell through a 1 millimeter hole. Two versions of pulsing techniques have been employed: a shutter blade which covers the source hole and opens it only for short moments, and a chopper that modulates the beam further downstream. Both produced pulse lengths around 1 millisecond. The source is tested in an experiment in which the emerging molecules are focused and detected. Time of flight technique is used to measure the kinetic energies. Two detectors have been employed: a microwave cavity to analyze the state of the molecules in the beam, and a mass spectrometer to measure the number density of the particles. The molecules coming out of the source hole are formed into a beam by an electrostatic quadrupole state selector. The quantum mechanical aspects and the elements of electrodynamics involved in the focusing are described. A computer simulation program is presented, which helped

  3. An Atmospheric Atomic Oxygen Source for Cleaning Smoke Damaged Art Objects

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Norris, Mary Jo

    1998-01-01

    Soot and other carbonaceous combustion products deposited on the surfaces of porous ceramic, stone, ivory and paper can be difficult to remove and can have potentially unsatisfactory results using wet chemical and/or abrasive cleaning techniques. An atomic oxygen source which operates in air at atmospheric pressure, using a mixture of oxygen and helium, has been developed to produce an atomic oxygen beam which is highly effective in oxidizing soot deposited on surfaces by burning candles made of paraffin, oil or rendered animal fat. Atomic oxygen source operating conditions and the results of cleaning soot from paper, gesso, ivory, limestone and water color-painted limestone are presented,

  4. Surface damage correction, and atomic level smoothing of optics by Accelerated Neutral Atom Beam (ANAB) Processing

    NASA Astrophysics Data System (ADS)

    Walsh, M.; Chau, K.; Kirkpatrick, S.; Svrluga, R.

    2014-10-01

    Surface damage and surface contamination of optics has long been a source of problems for laser, lithography and other industries. Nano-sized surface defects may present significant performance issues in optical materials for deep UV and EUV applications. The effects of nanometer sized surface damage (scratches, pits, and organics) on the surface of optics made of traditional materials and new more exotic materials is a limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, zinc sulfide, BK7 and others presents a unique set of challenges. Exogenesis Corporation, using its proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and contamination and leaves many material surfaces with roughness typically around one angstrom. This process technology has been demonstrated on nonlinear crystals, and various other high-end optical materials. This paper describes the ANAB technology and summarizes smoothing results for various materials that have been processed with ANAB. All surface measurement data for the paper was produced via AFM analysis. Exogenesis Corporation's ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply normal forces associated with traditional polishing techniques. ANAB efficiently removes surface contaminants, nano-scale scratches, bumps and other asperities under low energy physical sputtering conditions as the removal action proceeds. ANAB may be used to remove a precisely controlled, uniform thickness of material without any increase of surface roughness, regardless of the total amount of material removed. The ANAB process does not

  5. Search for Off-Diagonal Density Matrix Elements for Atoms in a Supersonic Beam

    NASA Astrophysics Data System (ADS)

    Rubenstein, Richard A.; Dhirani, Al-Amin; Kokorowski, David A.; Roberts, Tony D.; Smith, Edward T.; Smith, Winthrop W.; Bernstein, Herbert J.; Lehner, Jana; Gupta, Subhadeep; Pritchard, David E.

    1999-03-01

    We demonstrate the absence of off-diagonal elements for the density matrix of a supersonic Na atomic beam, thus showing that there are no coherent wave packets emerging from this source. We used a differentially detuned separated oscillatory field longitudinal interferometer to search for off-diagonal density matrix elements in the longitudinal energy/momentum basis. Our study places a stringent lower bound on their possible size over an off-diagonal energy range from 0 to 100 kHz.

  6. Versatile compact atomic source for high-resolution dual atom interferometry

    SciTech Connect

    Mueller, T.; Wendrich, T.; Gilowski, M.; Jentsch, C.; Rasel, E. M.; Ertmer, W.

    2007-12-15

    We present a compact {sup 87}Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a two-dimensional (2D) -MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our source generates a high atomic flux (>10{sup 10} atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e., temperature, absolute velocity, and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.

  7. High intensity muon beam source for neutrino beam experiments

    NASA Astrophysics Data System (ADS)

    Kamal Sayed, Hisham

    2015-09-01

    High intensity muon beams are essential for Muon accelerators like Neutrino Factories and Muon Colliders. In this study we report on a global optimization of the muon beam production and capture based on end-to-end simulations of the Muon Front End. The study includes the pion beam production target geometry, capture field profile, and forming muon beam into microbunches for further acceleration. The interplay between the transverse and longitudinal beam dynamics during the capture and transport of muon beam is evaluated and discussed. The goal of the optimization is to provide a set of design parameters that delivers high intensity muon beam that could be fit within the acceptance of a muon beam accelerator.

  8. Reactions of carbon atoms in pulsed molecular beams

    SciTech Connect

    Reisler, H.

    1993-12-01

    This research program consists of a broad scope of experiments designed to unravel the chemistry of atomic carbon in its two spin states, P and D, by using well-controlled initial conditions and state-resolved detection of products. Prerequisite to the proposed studies (and the reason why so little is known about carbon atom reactions), is the development of clean sources of carbon atoms. Therefore, in parallel with the studies of its chemistry and reaction dynamics, the authors continuously explore new, state-specific and efficient ways of producing atomic carbon. In the current program, C({sup 3}P) is produced via laser ablation of graphite, and three areas of study are being pursued: (i) exothermic reactions with small inorganic molecules (e.g., O{sub 2}, N{sub 2}O, NO{sub 2}) that can proceed via multiple pathways; (ii) the influence of vibrational and translational energy on endothermic reactions involving H-containing reactants that yield CH products (e.g., H{sub 2}O H{sub 2}CO); (iii) reactions of C({sup 3}P) with free radicals (e.g., HCO, CH{sub 3}O). In addition, the authors plan to develop a source of C({sup 1}D) atoms by exploiting the pyrolysis of diazotetrazole and its salts in the ablation source. Another important goal involves collaboration with theoreticians in order to obtain relevant potential energy surfaces, rationalize the experimental results and predict the roles of translational and vibrational energies.

  9. Development of broad beam ion sources at CSSAR

    NASA Astrophysics Data System (ADS)

    Feng, Y. C.; You, D. W.; Kuang, Y. Z.

    1994-04-01

    High-energy and intense beam current broad beam ion sources have been developed for ion implantation and dynamic recoil mixing at CSSAR. The sources can be operated over beam energy and current ranges of 3-120 keV and 5-70 mA, respectively. For sputter coating of thin films, a series of focusing beam ion sources with different structures has also been developed. The energy and current range from 1-10 keV and 100-350 mA for different applications. For some applications, low-energy (below 100 eV) ion beams are required. CSSAR has developed a 6-cm-diam broad beam ion source. The source can be operated at beam energy 10-70 eV, and the beam current 15-80 mA has been extracted. Typical structures and operational data are given for the sources mentioned above. Recently a new type of broad beam metal ion source (Electron Beam Evaporation Metal Ion Source EBE) is being studied. Ion beams of several kinds of materials such as C, W, Ta, Mo, Cr, Ti, B, Cu, etc. have been extracted from the source. Typical operation conditions and ion yields are given in this paper.

  10. Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

    SciTech Connect

    Haaf, G. ten; Wouters, S. H. W.; Vredenbregt, E. J. D.; Mutsaers, P. H. A.; Geer, S. B. van der

    2014-12-28

    Focused ion beams are indispensable tools in the semiconductor industry because of their ability to image and modify structures at the nanometer length scale. Here, we report on performance predictions of a new type of focused ion beam based on photo-ionization of a laser cooled and compressed atomic beam. Particle tracing simulations are performed to investigate the effects of disorder-induced heating after ionization in a large electric field. They lead to a constraint on this electric field strength which is used as input for an analytical model which predicts the minimum attainable spot size as a function of, amongst others, the flux density of the atomic beam, the temperature of this beam, and the total current. At low currents (I < 10 pA), the spot size will be limited by a combination of spherical aberration and brightness, while at higher currents, this is a combination of chromatic aberration and brightness. It is expected that a nanometer size spot is possible at a current of 1 pA. The analytical model was verified with particle tracing simulations of a complete focused ion beam setup. A genetic algorithm was used to find the optimum acceleration electric field as a function of the current. At low currents, the result agrees well with the analytical model, while at higher currents, the spot sizes found are even lower due to effects that are not taken into account in the analytical model.

  11. Note: Proof of principle of a new type of cluster beam source with potential for scale-up

    NASA Astrophysics Data System (ADS)

    Palmer, R. E.; Cao, L.; Yin, F.

    2016-04-01

    We introduce a new type of cluster beam source based on the assembly of (metal) clusters within a condensed (rare gas) matrix. The "Matrix Assembly Cluster Source" employs an ion beam to enhance collisions between metal atoms in the matrix and to sputter out clusters to form a beam. We demonstrate the formation and deposition of gold and silver nanoclusters with mean size tunable from a few atoms to a few thousand atoms. The cluster flux is equivalent to a current nanoAmp regime but potentially scalable to milliAmps, which would open up a number of interesting experiments and applications.

  12. Note: Proof of principle of a new type of cluster beam source with potential for scale-up.

    PubMed

    Palmer, R E; Cao, L; Yin, F

    2016-04-01

    We introduce a new type of cluster beam source based on the assembly of (metal) clusters within a condensed (rare gas) matrix. The "Matrix Assembly Cluster Source" employs an ion beam to enhance collisions between metal atoms in the matrix and to sputter out clusters to form a beam. We demonstrate the formation and deposition of gold and silver nanoclusters with mean size tunable from a few atoms to a few thousand atoms. The cluster flux is equivalent to a current nanoAmp regime but potentially scalable to milliAmps, which would open up a number of interesting experiments and applications. PMID:27131719

  13. Low-energy beam transport studies supporting the Spallation Neutron Source 1-MW beam operationa

    SciTech Connect

    Han, Baoxi; Kalvas, T.; Tarvainen, O.; Welton, Robert F; Murray Jr, S N; Pennisi, Terry R; Santana, Manuel; Stockli, Martin P

    2012-01-01

    The H- injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the Spallation Neutron Source 1-MW beam operation with ~38 mA beam current in the linac at 60 Hz with a pulse length of up to ~1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: 1) inconsistent dependence of the post-RFQ beam current on the ion source tilt angle, and 2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  14. He-diamond interaction probed by atom beam scattering

    NASA Astrophysics Data System (ADS)

    Vidali, G.; Frankl, D. R.

    1983-02-01

    A 4He atomic beam was used to probe the He-C (diamond) interaction. Selective adsorption features have been measured and three energy levels identified: 6.4, 3.0, and 1.1 meV with a standard deviation of 0.1 meV. Diffraction patterns showed weak diffraction up to the second order; a corrugation parameter of 0.021 Å was obtained with the use of a hard-wall model in the eikonal approximation. An extensive study of surface preparation was carried out and the results of 4He diffraction for different methods of surface cleaning are reported.

  15. The development of the high intensity electron cyclotron resonance ion source at China Institute of Atomic Energy.

    PubMed

    Tang, B; Ma, R; Ma, Y; Chen, L; Huang, Q; Liang, H; Cui, B; Jiang, W

    2014-02-01

    High-current microwave ion source has been under development over 15 years for accelerator driven sub-critical system research at China Institute of Atomic Energy, and the beam intensity higher than 140 mA proton beam is produced by this ion source with long lifetime and high reliability. The emittance of high intensity continue-wave and pulse beam is measured on a test-bench in the laboratory. Based on the good performance of this proton ion source, a new 120 mA deuterium ion source is proposed for a high intensity neutron generator. The ion source details and status will be presented. PMID:24593490

  16. The status of the Electron Beam Ion Sources

    SciTech Connect

    Stockli, M.P.

    1990-12-31

    More than twenty years after its invention, 13 examples of the Electron Beam Ion Sources (EBIS) are in operation worldwide. The substantial progress in operation and insight, achieved over the last few years, made the EBISes become reliable tools for the production of beams of very highly charged, low-energy ions. For example, 8 EBISes produce bare argon on a standard basis. The successful production of hydrogen-like xenon presents the ions with the highest ionization energy, whereas the production of Th80+ presents the highest achieved charge state. Several synchrotrons are fed by EBIS injectors, taking advantage of the EBIS batch mode production, which yields the highest charge states. A few EBISes are used for ion source development. However, most of the EBISes` efforts are directed to research the physics of highly charged ions. Some of those are used to study the electron--ion interaction inside the source. But normally, most EBISes deliver the ions for external experiments, which so far concentrate on the recombination of the highly charged ions with atoms, molecules and surfaces. The ions are typically produced at a potential of 1 to a few kilovolts per charge; but in most cases, the EBIS is mounted on a high voltage platform or is followed by an RFQ, and therefore can generate ion energies from a few hundred volts up to a few hundred kilovolts per charge. The delivered beams have a low emittance and a low energy spread, which is an advantage for high-resolution experiments. This paper presents briefly all operational EBISes, their capabilities, their achievements, and their contribution to physics research. 5 figs., 1 tab., 59 refs.

  17. The status of the Electron Beam Ion Sources

    SciTech Connect

    Stockli, M.P.

    1990-01-01

    More than twenty years after its invention, 13 examples of the Electron Beam Ion Sources (EBIS) are in operation worldwide. The substantial progress in operation and insight, achieved over the last few years, made the EBISes become reliable tools for the production of beams of very highly charged, low-energy ions. For example, 8 EBISes produce bare argon on a standard basis. The successful production of hydrogen-like xenon presents the ions with the highest ionization energy, whereas the production of Th80+ presents the highest achieved charge state. Several synchrotrons are fed by EBIS injectors, taking advantage of the EBIS batch mode production, which yields the highest charge states. A few EBISes are used for ion source development. However, most of the EBISes' efforts are directed to research the physics of highly charged ions. Some of those are used to study the electron--ion interaction inside the source. But normally, most EBISes deliver the ions for external experiments, which so far concentrate on the recombination of the highly charged ions with atoms, molecules and surfaces. The ions are typically produced at a potential of 1 to a few kilovolts per charge; but in most cases, the EBIS is mounted on a high voltage platform or is followed by an RFQ, and therefore can generate ion energies from a few hundred volts up to a few hundred kilovolts per charge. The delivered beams have a low emittance and a low energy spread, which is an advantage for high-resolution experiments. This paper presents briefly all operational EBISes, their capabilities, their achievements, and their contribution to physics research. 5 figs., 1 tab., 59 refs.

  18. New results in atomic physics at the Advanced Light Source

    SciTech Connect

    Schlachter, A.S.

    1995-01-01

    The Advanced Light Source is the world's first low-energy third-generation synchrotron radiation source. It has been running reliably and exceeding design specifications since it began operation in October 1993. It is available to a wide community of researchers in many scientific fields, including atomic and molecular science and chemistry. Here, new results in atomic physics at the Advanced Light Source demonstrate the opportunities available in atomic and molecular physics at this synchrotron light source. The unprecedented brightness allows experiments with high flux, high spectral resolution, and nearly 100% linear polarization.

  19. Source fabrication and lifetime for Li+ ion beams extracted from alumino-silicate sources.

    PubMed

    Roy, Prabir K; Greenway, Wayne G; Kwan, Joe W

    2012-04-01

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm(2) have been measured from lithium alumino-silicate ion sources at a temperature of ∼1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm(2), and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ∼40 h at ∼1275 °C, when pulsed at 0.05 Hz and with pulse length of ∼6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. The source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses. PMID:22559528

  20. Source fabrication and lifetime for Li{sup +} ion beams extracted from alumino-silicate sources

    SciTech Connect

    Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.

    2012-04-15

    A space-charge-limited beam with current densities (J) exceeding 1 mA/cm{sup 2} have been measured from lithium alumino-silicate ion sources at a temperature of {approx}1275 deg. C. At higher extraction voltages, the source appears to become emission limited with J{>=} 1.5 mA/cm{sup 2}, and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, {<=}0.25 mm thick, has a measured lifetime of {approx}40 h at {approx}1275 deg. C, when pulsed at 0.05 Hz and with pulse length of {approx}6 {mu}s each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. The source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

  1. Cold beam of isotopically pure Yb atoms by deflection using 1D-optical molasses

    NASA Astrophysics Data System (ADS)

    Rathod, K. D.; Singh, P. K.; Natarajan, Vasant

    2014-09-01

    We demonstrate generation of an isotopically pure beam of laser-cooled Yb atoms by deflection using 1D-optical molasses. Atoms in a collimated thermal beam are first slowed using a Zeeman Slower. They are then subjected to a pair of molasses beams inclined at $45^\\circ$ with respect to the slowed atomic beam. The slowed atoms are deflected and probed at a distance of 160 mm. We demonstrate selective deflection of the bosonic isotope $^{174}$Yb, and the fermionic isotope $^{171}$Yb. Using a transient measurement after the molasses beams are turned on, we find a longitudinal temperature of 41 mK.

  2. Coherence and its application in the beam-foil light source

    NASA Technical Reports Server (NTRS)

    Liu, C. H.; Bashkin, S.

    1974-01-01

    The beam-foil light source is shown to be very useful in spectroscopic work. Not only the lifetimes of highly excited, multiply charged atoms can be measured in a straightforward way, but also the fine-structure and hyperfine-structure separations and the Lande factors can be obtained due to the fact that the coherent excitations are created in the impulsive beam-foil collision. The theories suggested to explain the origin of coherence are presently incomplete.

  3. Thermal beam of metastable krypton atoms produced by optical excitation

    SciTech Connect

    Ding, Y.; Hu, S.-M.; Bailey, K.; Davis, A. M.; Dunford, R. W.; Lu, Z.-T.; O'Connor, T. P.; Young, L.

    2007-02-15

    A room-temperature beam of krypton atoms in the metastable 5s[3/2]{sub 2} level is demonstrated via an optical excitation method. A Kr-discharge lamp is used to produce vacuum ultraviolet photons at 124 nm for the first-step excitation from the ground level 4p{sup 6} {sup 1}S{sub 0} to the 5s[3/2]{sub 1} level. An 819 nm Ti:sapphire laser is used for the second-step excitation from 5s[3/2]{sub 1} to 5s[3/2]{sub 2} followed by a spontaneous decay to the 5s[3/2]{sub 2} metastable level. A metastable atomic beam with an angular flux density of 3x10{sup 14} s{sup -1} sr{sup -1} is achieved at the total gas flow rate of 0.01 cm{sup 3}/s at STP (or 3x10{sup 17} at./s). The dependences of the flux on the gas flow rate, laser power, and lamp parameters are investigated.

  4. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    SciTech Connect

    Sacramento, R. L.; Alves, B. X.; Silva, B. A.; Wolff, W.; Cesar, C. L.; Oliveira, A. N.; Li, M. S.

    2015-07-15

    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H{sub 2} are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  5. Advancing atomic nanolithography: cold atomic Cs beam exposure of alkanethiol self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    O'Dwyer, C.; Gay, G.; Viaris de Lesegno, B.; Weiner, J.; Mützel, M.; Haubrich, D.; Meschede, D.; Ludolph, K.; Georgiev, G.; Oesterschulze, E.

    2005-01-01

    We report the results of a study into the quality of functionalized surfaces for nanolithographic imaging. Self-assembled monolayer (SAM) coverage, subsequent post-etch pattern definition and minimum feature size all depend on the quality of the Au substrate used in atomic nanolithographic experiments. We find sputtered Au substrates yield much smoother surfaces and a higher density of {111} oriented grains than evaporated Au surfaces. A detailed study of the self-assembly mechanism using molecular resolution AFM and STM has shown that the monolayer is composed of domains with sizes typically of 5-25 nm, and multiple molecular domains can exist within one Au grain. Exposure of the SAM to an optically-cooled atomic Cs beam traversing a two-dimensional array of submicron material masks ans also standing wave optical masks allowed determination of the minimum average Cs dose (2 Cs atoms per SAM molecule) and the realization of < 50 nm structures. The SAM monolayer contains many non-uniformities such as pin-holes, domain boundaries and monoatomic depressions which are present in the Au surface prior to SAM adsorption. These imperfections limit the use of alkanethiols as a resist in atomic nanolithography experiments. These studies have allowed us to realize an Atom Pencil suitable for deposition of precision quantities of material at the microand nanoscale to an active surface.

  6. Fabrication of electron beam deposited tip for atomic-scale atomic force microscopy in liquid.

    PubMed

    Miyazawa, K; Izumi, H; Watanabe-Nakayama, T; Asakawa, H; Fukuma, T

    2015-03-13

    Recently, possibilities of improving operation speed and force sensitivity in atomic-scale atomic force microscopy (AFM) in liquid using a small cantilever with an electron beam deposited (EBD) tip have been intensively explored. However, the structure and properties of an EBD tip suitable for such an application have not been well-understood and hence its fabrication process has not been established. In this study, we perform atomic-scale AFM measurements with a small cantilever and clarify two major problems: contaminations from a cantilever and tip surface, and insufficient mechanical strength of an EBD tip having a high aspect ratio. To solve these problems, here we propose a fabrication process of an EBD tip, where we attach a 2 μm silica bead at the cantilever end and fabricate a 500-700 nm EBD tip on the bead. The bead height ensures sufficient cantilever-sample distance and enables to suppress long-range interaction between them even with a short EBD tip having high mechanical strength. After the tip fabrication, we coat the whole cantilever and tip surface with Si (30 nm) to prevent the generation of contamination. We perform atomic-scale AFM imaging and hydration force measurements at a mica-water interface using the fabricated tip and demonstrate its applicability to such an atomic-scale application. With a repeated use of the proposed process, we can reuse a small cantilever for atomic-scale measurements for several times. Therefore, the proposed method solves the two major problems and enables the practical use of a small cantilever in atomic-scale studies on various solid-liquid interfacial phenomena. PMID:25697199

  7. Description and analysis of a vacuum ultraviolet atomic line source.

    PubMed

    Kikuchi, T T

    1971-06-01

    An intense vacuum uv atomic line source excited in a 2450-MHz microwave discharge cavity is described and analyzed. Additional features are a clean spectrum, very little window deterioration, little or no self-absorption, and easily interchangeable parts. (For the O-atom source only the 1300-A triplet shows up over the 1200-A to 1650-A region.) This source is suitable for the detection of various species by absorption measurement in fast occurring events such as those in ballistic ranges and shock tubes. Atomic line shape theory is used to analyze an O-atom line source with intensity ratios I(1306A): I(1305A): I(1302A):1:2.9:4.5. This source is described by a 2700 +/- 200 K temperature and certain self-absorption parameters as deduced from the measurement of their intensity ratios and their transmission characteristics through known concentrations of O-atoms. A good theoretical fit to the measured transmission validates the assumed uniform source temperature and excitation for the analysis. An f value (f = 0.052 +/- 0.005) for the O-atom 1300-A triplet absorption and a collision diameter of 5.5 +/- 1.0 A between the O-atom and the nitrogen molecule were determined in the course of this study. PMID:20111107

  8. BEAM TRANSPORT AND STORAGE WITH COLD NEUTRAL ATOMS AND MOLECULES

    SciTech Connect

    Walstrom, Peter L.

    2012-05-15

    A large class of cold neutral atoms and molecules is subject to magnetic field-gradient forces. In the presence of a field, hyperfine atomic states are split into several Zeeman levels. The slopes of these curves vs. field are the effective magnetic moments. By means of optical pumping in a field, Zeeman states of neutral lithium atoms and CaH molecules with effective magnetic moments of nearly {+-} one Bohr magneton can be selected. Particles in Zeeman states for which the energy increases with field are repelled by increasing fields; particles in states for which the energy decreases with field are attracted to increasing fields. For stable magnetic confinement, field-repelled states are required. Neutral-particle velocities in the present study are on the order of tens to hundreds of m/s and the magnetic fields needed for transport and injection are on the order of in the range of 0.01-1T. Many of the general concepts of charged-particle beam transport carry over into neutral particle spin-force optics, but with important differences. In general, the role of bending dipoles in charged particle optics is played by quadrupoles in neutral particle optics; the role of quadrupoles is played by sextupoles. The neutralparticle analog of charge-exchange injection into storage rings is the use of lasers to flip the state of particles from field-seeking to field-repelled. Preliminary tracking results for two neutral atom/molecule storage ring configurations are presented. It was found that orbit instabilities limit the confinment time in a racetrack-shaped ring with discrete magnetic elements with drift spaces between them; stable behavior was observed in a toroidal ring with a continuous sextupole field. An alternative concept using a linear sextupole or octupole channel with solenoids on the ends is presently being considered.

  9. Atom trap for 221Fr from 225Ac ion beam implantation

    NASA Astrophysics Data System (ADS)

    Tandecki, M.; Behr, J. A.; Pearson, M. R.; Zhang, J.; Orozco, L.; Collister, R.; Gwinner, G.; Gomez, E.; Aubin, S.

    2012-10-01

    A neutral atom trap for francium parity violation experiments is being set up at TRIUMF. The half-lives of the longest isotopes are minutes, which mostly will be produced by the online mass separator of the ISAC facility. For systematic error studies for precision measurements, it can help to have a longer-lived source. ^221Fr is produced by t1/2=10 day ^225Ac α decay, and has been trapped at JILA [Z.-T. Lu PRL 79 994 (1997)]. Our approach would implant the mass-separated ^225Ac beam produced by ISAC at 1x10^7/s for a day after the production proton beam is turned off. The scheme to be tested: 30 keV ^225Ac beam is implanted in tantalum for a day; the sample is held in front of an yttrium foil (normally used to stop a mass-separated Fr beam) for 1 minute; 100 keV ^221Fr recoils escape and implant in the yttrium; tantalum is withdrawn, yttrium is moved to trap and heated; cycle repeats. First tests are planned for September, and one goal is precise measurements of atomic hyperfine splittings sensitive to the spatial distribution of nuclear magnetism.

  10. An atomic beam of 6Li — 7Li for high resolution spectroscopy from matrix isolation sublimation

    NASA Astrophysics Data System (ADS)

    Oliveira, A. N.; Sacramento, R. L.; Silva, B. A.; Uhlmann, F. O.; Wolff, W.; Cesar, C. L.

    2016-07-01

    We propose the Matrix Isolation Sublimation (MlSu) technique for generating cold lithium atoms for the measurement of the 6Li - 7Li isotope shift in D1 and D2 transitions. The technique is capable of generating cold 6Li and 7Li beams at 4 K with forward velocity of 125 m/s. Using this beam we offer a distinguished source of lithium atoms for transitions measurements, adding a new possibility to make high resolution spectroscopy towards improving the experimental checks of the theory.

  11. Single-beam three-axis atomic magnetometer

    NASA Astrophysics Data System (ADS)

    Huang, Haichao; Dong, Haifeng; Chen, Lin; Gao, Yang

    2016-08-01

    A single-beam atomic magnetometer being operated near zero-field and measuring three-axis fields simultaneously is demonstrated. We produce a rotating field on the x-0-y plane with the frequency of 90 Hz and a modulation field in the z axis at 130 Hz. The rotating field enables a nonzero z axis output when the transverse fields are zeroed using feedback systems. Based on the phase difference of π / 2 , x and y axes fields can be measured using one lock-in amplifier. Magnetic field sensitivities of 300 fT/Hz1/2 in x and y axes and 3 pT/Hz1/2 in the z axis are achieved.

  12. Multiscale modeling of electron beam and substrate interaction: a new heat source model

    NASA Astrophysics Data System (ADS)

    Yan, Wentao; Smith, Jacob; Ge, Wenjun; Lin, Feng; Liu, Wing Kam

    2015-08-01

    An electron beam is a widely applied processing tool in welding and additive manufacturing applications. The heat source model of the electron beam acts as the basis of thermal simulations and predictions of the micro-structures and mechanical properties of the final products. While traditional volumetric and surface heat flux models were developed previously based on the observed shape of the molten pool produced by the beam, a new heat source model with a physically informed foundation has been established in this work. The new model was developed based on Monte Carlo simulations performed to obtain the distribution of absorbed energy through electron-atom collisions for an electron beam with a kinetic energy of 60 keV hitting a Ti-6Al-4V substrate. Thermal simulations of a moving electron beam heating a solid baseboard were conducted to compare the differences between the new heat source model, the traditional surface flux model and the volumetric flux model. Although the molten pool shapes with the three selected models were found to be similar, the predicted peak temperatures were noticeably different, which will influence the evaporation, recoil pressure and molten pool dynamics. The new heat source model was also used to investigate the influence of a static electron beam on a substrate. This investigation indicated that the new heat source model could scientifically explain phenomena that the surface and volumetric models cannot, such as eruption and explosion during electron beam processing.

  13. Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency.

    PubMed

    Hanada, M; Kojima, A; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R

    2016-02-01

    In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications. PMID:26932050

  14. Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency

    NASA Astrophysics Data System (ADS)

    Hanada, M.; Kojima, A.; Tobari, H.; Nishikiori, R.; Hiratsuka, J.; Kashiwagi, M.; Umeda, N.; Yoshida, M.; Ichikawa, M.; Watanabe, K.; Yamano, Y.; Grisham, L. R.

    2016-02-01

    In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications.

  15. Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation.

    PubMed

    Majumder, A; Dikshit, B; Bhatia, M S; Mago, V K

    2008-09-01

    State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data. PMID:19044405

  16. Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

    SciTech Connect

    Majumder, A.; Dikshit, B.; Bhatia, M. S.; Mago, V. K.

    2008-09-15

    State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.

  17. Cooling of cesium atomic beam with light from spectrally broadened diode lasers

    NASA Astrophysics Data System (ADS)

    Chan, Yat; Bhaskar, Natarajan D.

    1995-12-01

    We have used spectrally broadened counterpropagating radiation from tunable diode lasers to cool an atomic beam of cesium. This produces a continuous beam of cold atoms. The injection current to the single-mode diode laser is modulated at 10 MHz, resulting in spectrally broadened light for atomic cooling and optical pumping. The atomic beam is probed with a weak single-mode laser. This is a simple and relatively inexpensive method for producing a continuous supply of cold atoms. Copyright (c) 1995 Optical Society of America

  18. Gyrotron and its Electron Beam Source: A Review

    NASA Astrophysics Data System (ADS)

    Singh, Udaybir; Kumar, Nitin; Sinha, AK

    2012-10-01

    Microwave occupies a glorious position in the electromagnetic spectrum and in that there are a number of devices in this frequency regime which are capable of high power operations. Among them, gyrotron has proven to be an efficient source for radio frequency (RF) generation at high power level and up to very high frequency. The gyrotron consists of several components like electron beam source, interaction structure, quasi-optical launcher, collector, RF window, magnet system, etc. All the components have their distinct role in the function of the device. Among them, electron beam source also called magnetron injection gun (MIG) is the generator of electron beam and it is very essential that MIG should produce and provide electron beam suitable for the beam-wave interaction at the interaction structure for the effective power growth. The paper presents the introduction of a microwave tube, gyrotron and its components alongwith review of the previous work, the background and the applications. The functions of various components of a gyrotron are discussed with particular highlighting on the electron beam emission from the electron beam source and the beam-wave interaction for power growth in the device. A review on different types of gyrotron electron beam sources is also presented.

  19. BEAM INSTRUMENTATION FOR THE SPALLATION NEUTRON SOURCE RING.

    SciTech Connect

    WITKOVER,R.L.; CAMERON,P.R.; SHEA,T.J.; CONNOLLY,R.C.; KESSELMAN,M.

    1999-03-29

    The Spallation Neutron Source (SNS) will be constructed by a multi-laboratory collaboration with BNL responsible for the transfer lines and ring. [1] The 1 MW beam power necessitates careful monitoring to minimize un-controlled loss. This high beam power will influence the design of the monitors in the high energy beam transport line (HEBT) from linac to ring, in the ring, and in the ring-to-target transfer line (RTBT). The ring instrumentation must cover a 3-decade range of beam intensity during accumulation. Beam loss monitoring will be especially critical since un-controlled beam loss must be kept below 10{sup -4}. A Beam-In-Gap (BIG) monitor is being designed to assure out-of-bucket beam will not be lost in the ring.

  20. BEAM LOSS MITIGATION IN THE OAK RIDGE SPALLATION NEUTRON SOURCE

    SciTech Connect

    Plum, Michael A

    2012-01-01

    The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and compare the design vs. the loss-minimized equipment parameters.

  1. Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    NASA Astrophysics Data System (ADS)

    Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

    2013-10-01

    Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

  2. Operating characteristics of a new ion source for KSTAR neutral beam injection system

    NASA Astrophysics Data System (ADS)

    Kim, Tae-Seong; Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

    2014-02-01

    A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

  3. An electron cyclotron resonance ion source based low energy ion beam platform.

    PubMed

    Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

    2008-02-01

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed. PMID:18315202

  4. Operating characteristics of a new ion source for KSTAR neutral beam injection system

    SciTech Connect

    Kim, Tae-Seong Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

    2014-02-15

    A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

  5. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Han, B. X.; Welton, R. F.; Murray, S. N. Jr.; Pennisi, T. R.; Santana, M.; Stockli, M. P.; Kalvas, T.; Tarvainen, O.

    2012-02-15

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  6. Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

    SciTech Connect

    Kalvas, T.; Welton, Robert F; Pennisi, Terry R

    2012-01-01

    The H{sup -} injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with {approx}38 mA beam current in the linac at 60 Hz with a pulse length of up to {approx}1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.

  7. Preparation of state purified beams of He, Ne, C, N, and O atoms

    NASA Astrophysics Data System (ADS)

    Jankunas, Justin; Reisyan, Kevin S.; Osterwalder, Andreas

    2015-03-01

    The production and guiding of ground state and metastable C, N, and O atoms in a two-meter-long, bent magnetic guide are described. Pure beams of metastable He(3S1) and Ne(3P2), and of ground state N(4S3/2) and O(3P2) are obtained using an Even-Lavie valve paired with a dielectric barrier discharge or electron bombardment source. Under these conditions no electronically excited C, N, or O atoms are observed at the exit of the guide. A general valve with electron impact excitation creates, in addition to ground state atoms, electronically excited C(3P2; 1D2) and N(2D5/2; 2P3/2) species. The two experimental conditions are complimentary, demonstrating the usefulness of a magnetic guide in crossed or merged beam experiments such as those described in Henson et al. [Science 338, 234 (2012)] and Jankunas et al. [J. Chem. Phys. 140, 244302 (2014)].

  8. Preparation of state purified beams of He, Ne, C, N, and O atoms

    SciTech Connect

    Jankunas, Justin; Reisyan, Kevin S.; Osterwalder, Andreas

    2015-03-14

    The production and guiding of ground state and metastable C, N, and O atoms in a two-meter-long, bent magnetic guide are described. Pure beams of metastable He({sup 3}S{sub 1}) and Ne({sup 3}P{sub 2}), and of ground state N({sup 4}S{sub 3/2}) and O({sup 3}P{sub 2}) are obtained using an Even-Lavie valve paired with a dielectric barrier discharge or electron bombardment source. Under these conditions no electronically excited C, N, or O atoms are observed at the exit of the guide. A general valve with electron impact excitation creates, in addition to ground state atoms, electronically excited C({sup 3}P{sub 2}; {sup 1}D{sub 2}) and N({sup 2}D{sub 5/2}; {sup 2}P{sub 3/2}) species. The two experimental conditions are complimentary, demonstrating the usefulness of a magnetic guide in crossed or merged beam experiments such as those described in Henson et al. [Science 338, 234 (2012)] and Jankunas et al. [J. Chem. Phys. 140, 244302 (2014)].

  9. Efficient magnetic guiding and deflection of atomic beams with moderate velocities

    NASA Astrophysics Data System (ADS)

    Goepfert, A.; Lison, F.; Schütze, R.; Wynands, R.; Haubrich, D.; Meschede, D.

    We have studied guidance and deflection of a beam of cesium atoms by a strong toroidal magnetic quadrupole field. The beam guide is made from permanent magnets sustaining a radial field gradient of 2.8 T/cm. Atoms with moderate longitudinal velocities ranging from 30 m/s to 70 m/s were inserted across the 10-mm-diameter aperture of a 24.5° arc with radius 300 mm. We have measured transmission and beam divergence and find good agreement with ray-tracing calculations and analytical estimates. The magnetic beam guide allows for 100% transmission of heavy atoms over large angles.

  10. Method and apparatus for producing a thermal atomic oxygen beam

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

    1994-01-01

    Atomic oxygen atoms are routed to a material through a sufficiently tortuous path so that vacuum ultraviolet radiation is obstructed from arriving at the surface of the material. However, the material surface continues to be exposed to the atomic oxygen.

  11. Dual-wavelength laser source for onboard atom interferometry.

    PubMed

    Ménoret, V; Geiger, R; Stern, G; Zahzam, N; Battelier, B; Bresson, A; Landragin, A; Bouyer, P

    2011-11-01

    We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components, which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto-optical trap in microgravity during parabolic flights. PMID:22048340

  12. Atomic physics at the Argonne PII ECR (electron cyclotron resonance) Ion Source

    SciTech Connect

    Dunford, R.W.; Berry, H.G.; Billquist, P.J.; Pardo, R.C.; Zabransky, B.J.; Bakke, E.; Groeneveld, K.O.; Hass, M.; Raphaelian, M.L.A.

    1987-01-01

    An atomic physics beam line has been set up at the Argonne PII ECR Ion Source. The source is on a 350-kV high-voltage platform which is a unique feature of particular interest in work on atomic collisions. We describe our planned experimental program which includes: measurement of state-selective electron-capture cross sections, studies of doubly-excited states, precision spectroscopy of few-electron ions, tests of quantum electrodynamics, and studies of polarization transfer using optically pumped polarized alkali targets. The first experiments will be measurements of cross sections for electron capture into specific nl subshells in ion-atom collisions. Our method is to observe the characteristic radiation emitted after capture using a VUV spectrometer. Initial data from these experiments are presented. 12 refs., 4 figs.

  13. Automation of neutral beam source conditioning with artificial intelligence techniques

    SciTech Connect

    Johnson, R.R.; Canales, T.W.; Lager, D.L.

    1985-01-01

    This paper describes a system that automates neutral beam source conditioning. The system achieves this with artificial intelligence techniques. The architecture of the system is presented followed by a description of its performance.

  14. Crossed-molecular-beams reactive scattering of oxygen atoms

    SciTech Connect

    Baseman, R.J.

    1982-11-01

    The reactions of O(/sup 3/P) with six prototypical unsaturated hydrocarbons, and the reaction of O(/sup 1/D) with HD, have been studied in high-resolution crossed-molecular-beams scattering experiments with mass-spectrometric detection. The observed laboratory-product angular and velocity distributions unambiguously identify parent-daughter ion pairs, distinguish different neutral sources of the same ion, and have been used to identify the primary products of the reactions. The derived center-of-mass product angular and translational energy distributions have been used to elucidate the detailed reaction dynamics. These results demonstrate that O(/sup 3/P)-unsaturated hydrocarbon chemistry is dominated by single bond cleavages, leading to radical products exclusively.

  15. Simulation of a beam rotation system for a spallation source

    NASA Astrophysics Data System (ADS)

    Reiss, Tibor; Reggiani, Davide; Seidel, Mike; Talanov, Vadim; Wohlmuther, Michael

    2015-04-01

    With a nominal beam power of nearly 1 MW on target, the Swiss Spallation Neutron Source (SINQ), ranks among the world's most powerful spallation neutron sources. The proton beam transport to the SINQ target is carried out exclusively by means of linear magnetic elements. In the transport line to SINQ the beam is scattered in two meson production targets and as a consequence, at the SINQ target entrance the beam shape can be described by Gaussian distributions in transverse x and y directions with tails cut short by collimators. This leads to a highly nonuniform power distribution inside the SINQ target, giving rise to thermal and mechanical stresses. In view of a future proton beam intensity upgrade, the possibility of homogenizing the beam distribution by means of a fast beam rotation system is currently under investigation. Important aspects which need to be studied are the impact of a rotating proton beam on the resulting neutron spectra, spatial flux distributions and additional—previously not present—proton losses causing unwanted activation of accelerator components. Hence a new source description method was developed for the radiation transport code MCNPX. This new feature makes direct use of the results from the proton beam optics code TURTLE. Its advantage to existing MCNPX source options is that all phase space information and correlations of each primary beam particle computed with TURTLE are preserved and transferred to MCNPX. Simulations of the different beam distributions together with their consequences in terms of neutron production are presented in this publication. Additionally, a detailed description of the coupling method between TURTLE and MCNPX is provided.

  16. Detailed atomic modeling of Sn plasmas for the EUV source

    NASA Astrophysics Data System (ADS)

    Sasaki, A.; Sunahara, A.; Nishihawra, K.; Nishikawa, T.; Koike, F.; Tanuma, H.

    2008-05-01

    An atomic model of Sn plasmas is developed to calculate coefficients of radiative transfer, based on the calculated atomic data using the Hullac code. We find that the emission spectrum and conversion efficiency depend critically on the wavelength and spectral structure of the 4d-4f transition arrays. Satellite lines, which have a significant contribution to the emission, are determined after iterative calculations by changing the number of levels in the atomic model. We also correct transition wavelengths through comparison with experiments. Using the present emissivity and opacity, the radiation hydrodynamics simulation will be carried out toward the optimization of the EUV source.

  17. Simulation of the low earth orbital atomic oxygen interaction with materials by means of an oxygen ion beam

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.; Paulsen, Phillip E.; Steuber, Thomas J.

    1989-01-01

    Atomic oxygen is the predominant species in low-Earth orbit between the altitudes of 180 and 650 km. These highly reactive atoms are a result of photodissociation of diatomic oxygen molecules from solar photons having a wavelength less than or equal to 2430A. Spacecraft in low-Earth orbit collide with atomic oxygen in the 3P ground state at impact energies of approximately 4.2 to 4.5 eV. As a consequence, organic materials previously used for high altitude geosynchronous spacecraft are severely oxidized in the low-Earth orbital environment. The evaluation of materials durability to atomic oxygen requires ground simulation of this environment to cost effectively screen materials for durability. Directed broad beam oxygen sources are necessary to evaluate potential spacecraft materials performance before and after exposure to the simulated low-Earth orbital environment. This paper presents a description of a low energy, broad oxygen ion beam source used to simulate the low-Earth orbital atomic oxygen environment. The results of materials interaction with this beam and comparison with actual in-space tests of the same meterials will be discussed. Resulting surface morphologies appear to closely replicate those observed in space tests.

  18. Exotic X-ray Sources from Intermediate Energy Electron Beams

    SciTech Connect

    Chouffani, K.; Wells, D.; Harmon, F.; Jones, J.L.; Lancaster, G.

    2003-08-26

    High intensity x-ray beams are used in a wide variety of applications in solid-state physics, medicine, biology and material sciences. Synchrotron radiation (SR) is currently the primary, high-quality x-ray source that satisfies both brilliance and tunability. The high cost, large size and low x-ray energies of SR facilities, however, are serious limitations. Alternatively, 'novel' x-ray sources are now possible due to new small linear accelerator (LINAC) technology, such as improved beam emittance, low background, sub-Picosecond beam pulses, high beam stability and higher repetition rate. These sources all stem from processes that produce Radiation from relativistic Electron beams in (crystalline) Periodic Structures (REPS), or the periodic 'structure' of laser light. REPS x-ray sources are serious candidates for bright, compact, portable, monochromatic, and tunable x-ray sources with varying degrees of polarization and coherence. Despite the discovery and early research into these sources over the past 25 years, these sources are still in their infancy. Experimental and theoretical research are still urgently needed to answer fundamental questions about the practical and ultimate limits of their brightness, mono-chromaticity etc. We present experimental results and theoretical comparisons for three exotic REPS sources. These are Laser-Compton Scattering (LCS), Channeling Radiation (CR) and Parametric X-Radiation (PXR)

  19. Electron temperature and concentration in a thermal atomic oxygen source

    NASA Technical Reports Server (NTRS)

    Pedrow, Patrick Dennis

    1990-01-01

    A thermal atomic oxygen source for materials screening was built for NASA by Boeing Aerospace. The objective here was to use a microwave interferometer and Langmuir probe to characterize the electron concentration in this thermal atomic oxygen source. Typical operating conditions in the thermal atomic oxygen source were found to produce electron concentrations that were well below the detection threshold of the interferometer (10(exp 8) cm (sup -3)). The researchers calibrated (with the interferometer) the Langmuir probe at an artificially high plasma density and then used the circular and the square Langmuir probes to measure the low electron concentrations that exist during materials exposure tests. Electron concentration was measured as a function of power and position. The electrons were lost to the walls through ambipolar diffusion, and their concentration was accurately described by an equation. The electron concentration was proportional to power squared and decayed exponentially with distance.

  20. The ``Beam Power'' of Classical Double Radio Sources

    NASA Astrophysics Data System (ADS)

    Wan, Lin; Daly, Ruth A.

    1995-12-01

    Powerful extended classical double radio sources are thought to be powered by a highly collimated outflow from an active galactic nucleus (AGN). An important parameter is the beam power or rate at which energy leaves the AGN in the form of a highly collimated outflow and is deposited in the vicinity of the radio hot spot and lobe. This drives a strong shock front into the ambient medium. Important parameters, such as the beam power, may be estimated using the radio properties of the lobe and bridge since these are related to the properties of the shock front. However, this requires detailed multifrequency radio observations of the radio lobes and bridge of the source. There are 2 samples in the published literature with enough radio information to be able to estimate the beam power of very powerful classical double sources; these are the samples of Leahy, Muxlow, and Stephens (1989) and Liu, Pooley, and Riley (1992). Using these samples we were able to estimate beam powers of 14 radio lobes from 8 radio loud quasars, and 27 radio lobes from 14 radio galaxies. The beam powers for these sources will be presented, and differences between radio loud quasars and radio galaxies will be discussed. The relation between the beam power and several quantities such as the radio power, the lobe propagation velocity, the source size, and the source redshift will be presented. The beam power is one of the important ingredients of the characteristic source size that allows classical doubles to be used as a cosmological tool (see the paper of Daly and Guerra at this meeting). The application of the beam power for this purpose will also be discussed.

  1. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOEpatents

    Cross, Jon B.; Cremers, David A.

    1988-01-01

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  2. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOEpatents

    Cross, J.B.; Cremers, D.A.

    1986-01-10

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  3. Fundamental limits on beam stability at the Advanced Photon Source.

    SciTech Connect

    Decker, G. A.

    1998-06-18

    Orbit correction is now routinely performed at the few-micron level in the Advanced Photon Source (APS) storage ring. Three diagnostics are presently in use to measure and control both AC and DC orbit motions: broad-band turn-by-turn rf beam position monitors (BPMs), narrow-band switched heterodyne receivers, and photoemission-style x-ray beam position monitors. Each type of diagnostic has its own set of systematic error effects that place limits on the ultimate pointing stability of x-ray beams supplied to users at the APS. Limiting sources of beam motion at present are magnet power supply noise, girder vibration, and thermal timescale vacuum chamber and girder motion. This paper will investigate the present limitations on orbit correction, and will delve into the upgrades necessary to achieve true sub-micron beam stability.

  4. Proposal of a truncated atomic beam fountain for reduction of collisional frequency shift

    SciTech Connect

    Takamizawa, A.; Yanagimachi, S.; Ikegami, T.; Shirakawa, Y.

    2010-07-15

    We propose an atomic fountain clock with a truncated cold atomic beam to achieve both a low collisional frequency shift and high frequency stability. In this clock, the launching velocity of a cold atomic beam can be swept to reduce the atomic density in the interrogation region for the Ramsey resonance and to increase the atomic density in the detection region. Before the top of the beam arrives at the interrogation region, the cold atomic beam is truncated by turning off the cooling laser beams to remove the unnecessary light shift. The atomic density in the interrogation region is theoretically evaluated to be 0.04 times that in an ordinary atomic fountain with optical molasses for the same number of detected atoms. The frequency stability limit due to quantum projection noise is calculated to reach 6.4x10{sup -14} in 1 s from the number of detected atoms while the fractional collisional shift is estimated to be {approx}{sup -}2x10{sup -16}.

  5. Extracting source parameters from beam monitors on a chopper spectrometer

    SciTech Connect

    Abernathy, Douglas L; Niedziela, Jennifer L; Stone, Matthew B

    2015-01-01

    The intensity distributions of beam monitors in direct-geometry time-of-flight neutron spectrometers provide important information about the instrument resolution. For short-pulse spallation neutron sources in particular, the asymmetry of the source pulse may be extracted and compared to Monte Carlo source simulations. An explicit formula using a Gaussian-convolved Ikeda-Carpenter distribution is given and compared to data from the ARCS instrument at the Spallation Neutron Source.

  6. Development of series H{sup −} multicusp ion source at China Institute of Atomic Energy

    SciTech Connect

    TianJue, Zhang; XianLu, Jia ZhenGuo, Li; Yinlong, Lu; JiuChang, Qin; Xia, Zheng; Hongjuan, Yao; JunQing, Zhong; GaoFeng, Pan; Tao, Ge; Fengping, Guan

    2014-02-15

    The development of H{sup −} multicusp ion sources has been carried out at China Institute of Atomic Energy (CIAE) for more than ten years. The first H{sup −} ion source with 5.2 mA was made in 2002. After improving the configured magnetic field, a H{sup −} ion source of 10 mA was made in 2004, and the beam intensity of 15 mA was obtained in 2008 after further improvements of the filter field. The beam intensity of 18 mA was achieved in 2010 following the in-depth study and optimization on some essential operation conditions. Now a series of H{sup −} cusp sources with different sizes and beam intensity ranging from 3 mA to 18 mA have been successfully developed at CIAE. All the ion sources can fast finish the test on the test stand now, since all the connections are modularized and can fit all kinds of H{sup −} mulitcusp source of CIAE. The development status of the various H{sup −} multicusp ion sources at CIAE are presented in the paper.

  7. A multi-channel tunable source for atomic sensors

    NASA Astrophysics Data System (ADS)

    Bigelow, Matthew S.; Roberts, Tony D.; McNeil, Shirley A.; Hawthorne, Todd; Battle, Phil

    2015-09-01

    We have designed and completed initial testing on a laser source suitable for atomic interferometry from compact, robust, integrated components. Our design is enabled by capitalizing on robust, well-commercialized, low-noise telecom components with high reliability and declining costs which will help to drive the widespread deployment of this system. The key innovation is the combination of current telecom-based fiber laser and modulator technology with periodicallypoled waveguide technology to produce tunable laser light at rubidium D1 and D2 wavelengths (and expandable to other alkalis) using second harmonic generation (SHG). Unlike direct-diode sources, this source is immune to feedback at the Rb line eliminating the need for bulky high-power isolators in the system. In addition, the source has GHz-level frequency agility and in our experiments was found to only be limited by the agility of our RF generator. As a proof-of principle, the source was scanned through the Doppler-broadened Rb D2 absorption line. With this technology, multiple channels can be independently tuned to produce the fields needed for addressing atomic states in atom interferometers and clocks. Thus, this technology could be useful in the development cold-atom inertial sensors and gyroscopes.

  8. A reflex electron beam discharge as a plasma source for electron beam generation

    SciTech Connect

    Murray, C.S.; Rocca, J.J.; Szapiro, B. )

    1988-10-01

    A reflex electron beam glow discharge has been used as a plasma source for the generation of broad-area electron beams. An electron current of 120 A (12 A/cm/sup 2/) was extracted from the plasma in 10 ..mu..s pulses and accelerated to energies greater than 1 keV in the gap between two grids. The scaling of the scheme for the generation of multikiloamp high-energy beams is discussed.

  9. Transverse coupling property of beam from ECR ion sources

    SciTech Connect

    Yang, Y.; Yuan, Y. J.; Sun, L. T.; Feng, Y. C.; Fang, X.; Cao, Y.; Lu, W.; Zhang, X. Z.; Zhao, H. W.

    2014-11-15

    Experimental evidence of the property of transverse coupling of beam from Electron Cyclotron Resonance (ECR) ion source is presented. It is especially of interest for an ECR ion source, where the cross section of extracted beam is not round along transport path due to the magnetic confinement configuration. When the ions are extracted and accelerated through the descending axial magnetic field at the extraction region, the horizontal and vertical phase space strongly coupled. In this study, the coupling configuration between the transverse phase spaces of the beam from ECR ion source is achieved by beam back-tracking simulation based on the measurements. The reasonability of this coupling configuration has been proven by a series of subsequent simulations.

  10. Cold electron sources using laser-cooled atoms

    NASA Astrophysics Data System (ADS)

    McCulloch, Andrew J.; Sparkes, Ben M.; Scholten, Robert E.

    2016-08-01

    Since the first observation of electron diffraction in 1927, electrons have been used to probe the structure of matter. High-brightness sources of thermal electrons have recently emerged that are capable of simultaneously providing high spatial resolving power along with ultrafast temporal resolution, however they are yet to demonstrate the holy grail of single-shot diffraction of non-crystalline objects. The development of the cold atom electron source, based around the ionisation of laser cooled atoms, has the potential to contribute to this goal. Electron generation from laser cooled atoms is in its infancy, but in just ten years has moved from a proposal to a source capable of performing single-shot diffraction imaging of crystalline structures. The high brightness, high transverse coherence length, and small energy spread of cold electron sources are also potentially advantageous for applications ranging from seeding of x-ray free-electron lasers and synchrotrons to coherent diffractive imaging and microscopy. In this review we discuss the context which motivates the development of these sources, the operating principles of the source, and recent experimental results. The achievements demonstrated thus far combined with theoretical proposals to alleviate current bottlenecks in development promise a bright future for these sources.

  11. Characterization of a 5-eV neutral atomic oxygen beam facility

    NASA Technical Reports Server (NTRS)

    Vaughn, J. A.; Linton, R. C.; Carruth, M. R., Jr.; Whitaker, A. F.; Cuthbertson, J. W.; Langer, W. D.; Motley, R. W.

    1991-01-01

    An experimental effort to characterize an existing 5-eV neutral atomic oxygen beam facility being developed at Princeton Plasma Physics Laboratory is described. This characterization effort includes atomic oxygen flux and flux distribution measurements using a catalytic probe, energy determination using a commercially designed quadrupole mass spectrometer (QMS), and the exposure of oxygen-sensitive materials in this beam facility. Also, comparisons were drawn between the reaction efficiencies of materials exposed in plasma ashers, and the reaction efficiencies previously estimated from space flight experiments. The results of this study show that the beam facility is capable of producing a directional beam of neutral atomic oxygen atoms with the needed flux and energy to simulate low Earth orbit (LEO) conditions for real time accelerated testing. The flux distribution in this facility is uniform to +/- 6 percent of the peak flux over a beam diameter of 6 cm.

  12. Absorption spectroscopy characterization measurements of a laser-produced Na atomic beam

    SciTech Connect

    Ching, C.H.; Bailey, J.E.; Lake, P.W.; Filuk, A.B.; Adams, R.G.; McKenney, J.

    1996-06-01

    This work describes a pulsed Na atomic beam source developed for spectroscopic diagnosis of a high-power ion diode on the Particle Beam Fusion Accelerator II. The goal is to produce a {approximately} 10{sup 12}-cm{sup {minus}3}-density Na atomic beam that can be injected into the diode acceleration gap to measure electric and magnetic fields from the Stark and Zeeman effects through laser-induced-fluorescence or absorption spectroscopy. A {approximately} 10 ns fwhm, 1.06 {micro}m, 0.6 J/cm{sup 2} laser incident through a glass slide heats a Na-bearing thin film, creating a plasma that generates a sodium vapor plume. A {approximately} 1 {micro}sec fwhm dye laser beam tuned to 5,890 {angstrom} is used for absorption measurement of the Na I resonant doublet by viewing parallel to the film surface. The dye laser light is coupled through a fiber to a spectrograph with a time-integrated CCD camera. A two-dimensional mapping of the Na vapor density is obtained through absorption measurements at different spatial locations. Time-of-flight and Doppler broadening of the absorption with {approximately} 0.1 {angstrom} spectral resolution indicate that the Na neutral vapor temperature is about 0.5 to 2 eV. Laser-induced-fluorescence from {approximately} 1 {times} 10{sup 12}-cm{sup {minus}3} Na I 3s-3p lines observed with a streaked spectrograph provides a signal level sufficient for {approximately} 0.06 {angstrom} wavelength shift measurements in a mock-up of an ion diode experiment.

  13. Novel oxygen atom source for material degradation studies

    NASA Technical Reports Server (NTRS)

    Krech, R. H.; Caledonia, G. E.

    1988-01-01

    Physical Sciences Inc. (PSI) has developed a high flux pulsed source of energetic (8 km/s) atomic oxygen to bombard specimens in experiments on the aging and degradation of materials in a low earth orbit environment. The proof-of-concept of the PSI approach was demonstrated in a Phase 1 effort. In Phase 2 a large O-atom testing device (FAST-2) has been developed and characterized. Quantitative erosion testing of materials, components, and even small assemblies (such as solar cell arrays) can be performed with this source to determine which materials and/or components are most vulnerable to atomic oxygen degradation. The source is conservatively rated to irradiate a 100 sq cm area sample at greater than 10(exp 17) atoms/s, at a 10 Hz pulse rate. Samples can be exposed to an atomic oxygen fluence equivalent to the on-orbit ram direction exposure levels incident on Shuttle surfaces at 250 km during a week-long mission in a few hours.

  14. Beam measurements on the H- source and Low Energy Beam Transport system for the Spallation Neutron Source

    SciTech Connect

    Thomae, R.; Gough, R.; Keller, R.; Leung, K.N.; Schenkel, T.; Aleksandrov, A.; Stockli, M.; Welton, R.

    2001-09-01

    The ion source and Low Energy Beam Transport section of the front-end systems presently being built by Berkeley Lab are required to provide 50 mA of H - beam current at 6% duty factor (1 ms pulses at 60 Hz) with a normalized rms emittance of less than 0.20 p-mm-mrad. Experimental results, including emittance, chopping, and steering measurements, on the performance of the ion source and LEBT system operated at the demanded beam parameters will be discussed.

  15. ALLIGATOR - An apparatus for ion beam assisted deposition with a broad-beam ion source

    NASA Astrophysics Data System (ADS)

    Wituschek, H.; Barth, M.; Ensinger, W.; Frech, G.; Rück, D. M.; Leible, K. D.; Wolf, G. K.

    1992-04-01

    Ion beam assisted deposition is a versatile technique for preparing thin films and coatings for various applications. Up to now a prototype setup for research purposes has been used in our laboratory. Processing of industrial standard workpieces requires a high current ion source with broad beam and high uniformity for homogeneous bombardment. In this contribution a new apparatus for large area samples will be described. It is named ALLIGATOR (German acronym of facility for ion assisted evaporation on transverse movable or rotary targets). In order to have a wide energy range available two ion sources are used. One delivers a beam energy up to 1.3 keV. The other is suitable for energies from 5 keV up to 40 keV. The ``high-energy'' ion source is a multicusp multiaperture source with 180-mA total current and a beam diameter of 280 mm at the target position.

  16. Measurement of the force on microparticles in a beam of energetic ions and neutral atoms

    SciTech Connect

    Trottenberg, Thomas; Schneider, Viktor; Kersten, Holger

    2010-10-15

    The force on microparticles in an energetic ion beam is investigated experimentally. Hollow glass microspheres are injected into the vertically upward directed beam and their trajectories are recorded with a charge-coupled device camera. The net force on the particles is determined by means of the measured vertical acceleration. The resulting beam pressures are compared with Faraday cup measurements of the ion current density and calorimetric measurements of the beam power density. Due to the neutral gas background, the beam consists, besides the ions, of energetic neutral atoms produced by charge-exchange collisions. It is found that the measured composition of the drag force by an ion and a neutral atom component agrees with a beam model that takes charge-exchange collisions into account. Special attention is paid to the momentum contribution from sputtered atoms, which is shown to be negligible in this experiment, but should become measurable in case of materials with high sputtering yields.

  17. Small radio frequency driven multicusp ion source for positive hydrogen ion beam production

    SciTech Connect

    Perkins, L.T.; Herz, P.R.; Leung, K.N.; Pickard, D.S. )

    1994-04-01

    A compact, 2.5 cm diam rf-driven multicusp ion source has been developed and tested for H[sup +] ion production in pulse mode operation. The source is optimized for atomic hydrogen ion species and extractable current. It is found that hydrogen ion beam current densities in excess of 650 mA/cm[sup 2] can be achieved with H[sup +] species above 80%. The geometry and position of the porcelain-coated copper antenna were found to be of great significance in relation to the efficiency of the ion source.

  18. Antimony-assisted carbonization of Si(111) with solid source molecular beam epitaxy

    SciTech Connect

    Hackley, Justin; Richardson, Christopher J. K.; Sarney, Wendy L.

    2013-11-15

    The carbonization of an antimony-terminated Si (111) surface in a solid source molecular beam epitaxy system is presented. Reflection high-energy electron diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and cross-sectional transmission electron microscopy are used to characterize samples grown with and without antimony termination. It is shown that the antimony-terminated surface promotes the formation of thin, smooth and continuous SiC films at a relatively low temperature of 800 °C.

  19. Cryogenic Microjet Source for Orthotropic Beams of Ultralarge Superfluid Helium Droplets

    NASA Astrophysics Data System (ADS)

    Grisenti, Robert E.; Toennies, J. Peter

    2003-06-01

    Liquid 4He at pressures P0=0.5 30 bars and temperatures T0=1.5 4.2 K is discharged into vacuum through two different 2 μm nozzles. The velocities of the beam of particles obey the Bernoulli equation down to 15 m/sec. With decreasing T0 and increasing P0 the velocity and angular distributions become exceedingly narrow with Δv/v≲1% and Δϑ≲1 mrad. Optical observations indicate that the beam consists of micron-sized droplets (N≳109 atoms). This new droplet source provides opportunities for novel experimental studies of superfluid behavior.

  20. Numerical simulation of ion charge breeding in electron beam ion source

    SciTech Connect

    Zhao, L. Kim, Jin-Soo

    2014-02-15

    The Electron Beam Ion Source particle-in-cell code (EBIS-PIC) tracks ions in an EBIS electron beam while updating electric potential self-consistently and atomic processes by the Monte Carlo method. Recent improvements to the code are reported in this paper. The ionization module has been improved by using experimental ionization energies and shell effects. The acceptance of injected ions and the emittance of extracted ion beam are calculated by extending EBIS-PIC to the beam line transport region. An EBIS-PIC simulation is performed for a Cs charge-breeding experiment at BNL. The charge state distribution agrees well with experiments, and additional simulation results of radial profiles and velocity space distributions of the trapped ions are presented.

  1. Rapid communicationPattern generation with cesium atomic beams at nanometer scales

    NASA Astrophysics Data System (ADS)

    Kreis, M.; Lison, F.; Haubrich, D.; Meschede, D.; Nowak, S.; Pfau, T.; Mlynek, J.

    1996-12-01

    We have demonstrated that a cesium atomic beam can be used to pattern a gold surface using a self assembling monolayer (SAM) as a resist. A 12.5 μm period mesh was used as a proximity mask for the atomic beam. The cesium atoms locally change the wetability of the SAM, which allows a wet etching reagent to remove the underlying gold in the exposed regions. An edge resolution of better than 100 nm was obtained. The experiment suggests that this method can either be used as a sensitive position detector with nanometer resolution in atom optics, or for nanostructuring in a resist technique.

  2. Laser cooling of an indium atomic beam enabled by magnetic fields

    NASA Astrophysics Data System (ADS)

    Klöter, B.; Weber, C.; Haubrich, D.; Meschede, D.; Metcalf, H.

    2008-03-01

    We demonstrate magnetic field enabled optical forces on a neutral indium atomic beam in a light field consisting of five frequencies. The role of dark magnetic ground state sublevels is studied and enables us to cool the atomic beam transversely to near the Doppler limit with laser frequencies tuned above the atomic resonance. The effect of laser cooling can be explained with transient effects in the light potential created by the standing wave light field where the atoms are optically pumped into the dark states and recycled by Larmor precession.

  3. Beam intensity increases at the intense pulsed neutron source accelerator

    SciTech Connect

    Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6..mu..A (3.25 x 10/sup 12/ protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current.

  4. Final design of the beam source for the MITICA injector.

    PubMed

    Marcuzzi, D; Agostinetti, P; Dalla Palma, M; De Muri, M; Chitarin, G; Gambetta, G; Marconato, N; Pasqualotto, R; Pavei, M; Pilan, N; Rizzolo, A; Serianni, G; Toigo, V; Trevisan, L; Visentin, M; Zaccaria, P; Zaupa, M; Boilson, D; Graceffa, J; Hemsworth, R S; Choi, C H; Marti, M; Roux, K; Singh, M J; Masiello, A; Froeschle, M; Heinemann, B; Nocentini, R; Riedl, R; Tobari, H; de Esch, H P L; Muvvala, V N

    2016-02-01

    The megavolt ITER injector and concept advancement experiment is the prototype and the test bed of the ITER heating and current drive neutral beam injectors, currently in the final design phase, in view of the installation in Padova Research on Injector Megavolt Accelerated facility in Padova, Italy. The beam source is the key component of the system, as its goal is the generation of the 1 MeV accelerated beam of deuterium or hydrogen negative ions. This paper presents the highlights of the latest developments for the finalization of the MITICA beam source design, together with a description of the most recent analyses and R&D activities carried out in support of the design. PMID:26932037

  5. Quasi-Bessel beams from asymmetric and astigmatic illumination sources.

    PubMed

    Müller, Angelina; Wapler, Matthias C; Schwarz, Ulrich T; Reisacher, Markus; Holc, Katarzyna; Ambacher, Oliver; Wallrabe, Ulrike

    2016-07-25

    We study the spatial intensity distribution and the self-reconstruction of quasi-Bessel beams produced from refractive axicon lenses with edge emitting laser diodes as asymmetric and astigmatic illumination sources. Comparing these to a symmetric mono-mode fiber source, we find that the asymmetry results in a transition of a quasi-Bessel beam into a bow-tie shaped pattern and eventually to a line shaped profile at a larger distance along the optical axis. Furthermore, we analytically estimate and discuss the effects of astigmatism, substrate modes and non-perfect axicons. We find a good agreement between experiment, simulation and analytic considerations. Results include the derivation of a maximal axicon angle related to astigmatism of the illuminating beam, impact of laser diode beam profile imperfections like substrate modes and a longitudinal oscillation of the core intensity and radius caused by a rounded axicon tip. PMID:27464190

  6. Tabletop Ultrabright Kiloelectronvolt X-Ray Sources from Xe and Kr Hollow Atom States

    NASA Astrophysics Data System (ADS)

    Sankar, Poopalasingam

    Albert Einstein, the father of relativity, once said, "Look deep into nature, and then you will understand everything better". Today available higher resolution tabletop tool to look deep into matters and living thing is an x-ray source. Although the available tabletop x-rays sources of the 20th century, such as the ones used for medical or dental x-rays are tremendously useful for medical diagnostics and industry, a major disadvantage is that they have low quality skillful brightness, which limits its resolution and accuracy. In the other hand, x-ray free-electrons laser (XFEL) and synchrotron radiation sources provided extreme bright x-rays. However, number of applications of XFEL and synchrotron such as medical and industrials, has been hampered by their size, complexity, and cost. This has set a goal of demonstrating x-ray source with enough brightness for potential applications in an often-called tabletop compact x-ray source that could be operated in university laboratory or hospitals. We have developed two tabletop ultrabright keV x-ray sources, one from a Xe hollow-atom states and the other one from Kr hollow-atom stares with a unique characteristic that makes them complementary to currently-available extreme-light sources; XFEL, and synchrotron x-ray source. Upgraded tabletop ultra-fast KrF* pump-laser interacts with target rare-gas clusters and produces hollow-atom states, which later coherently collapse to the empty inner-shell and thereby generate keV x-ray radiation. The KrF* pump-laser beam is self-focused and forms a self-channel to guide the generated x-ray radiation in the direction of the pump-laser beam to produce directed x-ray beam. Xe (M) x-ray source operates at 1.2-1.6 nm wavelength while the Kr(L) x-ray source operates in 600-800 pm wavelength. System is mounted upon 3 optical-tables (5´x12´) with two KrF amplifiers at a repetition rate of 0.1 Hz. A lower bound for brightness value for both Xe and Kr x-ray sources is 1026 photons s-1mm-2

  7. Effective shielding to measure beam current from an ion source

    SciTech Connect

    Bayle, H.; Delferrière, O.; Gobin, R.; Harrault, F.; Marroncle, J.; Senée, F.; Simon, C.; Tuske, O.

    2014-02-15

    To avoid saturation, beam current transformers must be shielded from solenoid, quad, and RFQ high stray fields. Good understanding of field distribution, shielding materials, and techniques is required. Space availability imposes compact shields along the beam pipe. This paper describes compact effective concatenated magnetic shields for IFMIF-EVEDA LIPAc LEBT and MEBT and for FAIR Proton Linac injector. They protect the ACCT Current Transformers beyond 37 mT radial external fields. Measurements made at Saclay on the SILHI source are presented.

  8. Electron Beam Collimation for the Next Generation Light Source

    SciTech Connect

    Steier, C.; Emma, P.; Nishimura, H.; Papadopoulos, C.; Sannibale, F.

    2013-05-20

    The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the early conceptual design of a collimation system, as well as initial results of simulations to test its effectiveness.

  9. Versatile cold atom source for multi-species experiments

    NASA Astrophysics Data System (ADS)

    Paris-Mandoki, A.; Jones, M. D.; Nute, J.; Wu, J.; Warriar, S.; Hackermüller, L.

    2014-11-01

    We present a dual-species oven and Zeeman slower setup capable of producing slow, high-flux atomic beams for loading magneto-optical traps. Our compact and versatile system is based on electronic switching between different magnetic field profiles and is applicable to a wide range of multi-species experiments. We give details of the vacuum setup, coils, and simple electronic circuitry. In addition, we demonstrate the performance of our system by optimized, sequential loading of magneto-optical traps of lithium-6 and cesium-133.

  10. Versatile cold atom source for multi-species experiments

    SciTech Connect

    Paris-Mandoki, A.; Jones, M. D.; Nute, J.; Warriar, S.; Hackermüller, L.; Wu, J.

    2014-11-15

    We present a dual-species oven and Zeeman slower setup capable of producing slow, high-flux atomic beams for loading magneto-optical traps. Our compact and versatile system is based on electronic switching between different magnetic field profiles and is applicable to a wide range of multi-species experiments. We give details of the vacuum setup, coils, and simple electronic circuitry. In addition, we demonstrate the performance of our system by optimized, sequential loading of magneto-optical traps of lithium-6 and cesium-133.

  11. Laser sources for precision spectroscopy on atomic strontium.

    PubMed

    Poli, N; Ferrari, G; Prevedelli, M; Sorrentino, F; Drullinger, R E; Tino, G M

    2006-04-01

    We present a new laser setup designed for high-precision spectroscopy on laser cooled atomic strontium. The system, which is entirely based on semiconductor laser sources, delivers 200 mW at 461 nm for cooling and trapping atomic strontium from a thermal source, 4 mW at 497 nm for optical pumping from the metastable P23 state, 12 mW at 689 nm on linewidth less than 1 kHz for second-stage cooling of the atomic sample down to the recoil limit, 1.2 W at 922 nm for optical trapping close to the "magic wavelength" for the 0-1 intercombination line at 689 nm. The 689 nm laser was already employed to perform a frequency measurement of the 0-1 intercombination line with a relative accuracy of 2.3 x 10(-11), and the ensemble of laser sources allowed the loading in a conservative dipole trap of multi-isotopes strontium mixtures. The simple and compact setup developed represents one of the first steps towards the realization of a transportable optical standards referenced to atomic strontium. PMID:16527534

  12. Virtual source for a Laguerre-Gauss beam

    NASA Astrophysics Data System (ADS)

    Seshadri, S. R.

    2002-11-01

    A virtual source that generates a cylindrically symmetric Laguerre-Gauss wave of radial mode number n is introduced. An expression is derived for this Laguerre-Gauss wave that in the appropriate limit yields the corresponding Laguerre-Gauss beam. From the spectral representation of the Laguerre-Gauss wave, the first three orders of nonparaxial corrections for the paraxial Laguerre-Gauss beam are determined. On the beam axis, the number of orders of nonvanishing nonparaxial corrections is found to be equal to n.

  13. Random sources for beams with azimuthally varying polarization properties.

    PubMed

    Wang, Fei; Korotkova, Olga

    2016-07-11

    We develop analytical model for statistically stationary sources that radiate beam-like far fields with polarization properties separately controllable in both radial and azimuthal variables. In particular, we demonstrate that for a suitable choice of source parameters a vortex-like far-field distribution of the degree of polarization (DOP) can be obtained. Furthermore, we report the experimental generation of such sources using an optical setup with Mach-Zehnder interferometer having two independent spatial light modulators in its branches. The experimental results agree well with the theoretical predictions. The new class of sources may find uses in imaging, communication and sensing applications based on source polarization diversity. PMID:27410819

  14. Plasma ion sources and ion beam technology inmicrofabrications

    SciTech Connect

    Ji, Lili

    2007-01-01

    For over decades, focused ion beam (FIB) has been playing a very important role in microscale technology and research, among which, semiconductor microfabrication is one of its biggest application area. As the dimensions of IC devices are scaled down, it has shown the need for new ion beam tools and new approaches to the fabrication of small-scale devices. In the meanwhile, nanotechnology has also deeply involved in material science research and bioresearch in recent years. The conventional FIB systems which utilize liquid gallium ion sources to achieve nanometer scale resolution can no longer meet the various requirements raised from such a wide application area such as low contamination, high throughput and so on. The drive towards controlling materials properties at nanometer length scales relies on the availability of efficient tools. In this thesis, three novel ion beam tools have been developed and investigated as the alternatives for the conventional FIB systems in some particular applications. An integrated focused ion beam (FIB) and scanning electron microscope (SEM) system has been developed for direct doping or surface modification. This new instrument employs a mini-RF driven plasma source to generate focused ion beam with various ion species, a FEI two-lens electron (2LE) column for SEM imaging, and a five-axis manipulator system for sample positioning. An all-electrostatic two-lens column has been designed to focus the ion beam extracted from the source. Based on the Munro ion optics simulation, beam spot sizes as small as 100 nm can be achieved at beam energies between 5 to 35 keV if a 5 μm-diameter extraction aperture is used. Smaller beam spot sizes can be obtained with smaller apertures at sacrifice of some beam current. The FEI 2LE column, which utilizes Schottky emission, electrostatic focusing optics, and stacked-disk column construction, can provide high-resolution (as small as 20 nm) imaging capability, with fairly long working distance (25

  15. ATOMIC BEAM POLARIZATION MEASUREMENT OF THE RHIC POLARIZED H-JET TARGET.

    SciTech Connect

    MAKDISI,Y.; NASS,A.; GRAHAM,D.; KPONOU,A.; MAHLER,G.; MENG,W.; RITTER,J.; ET AL.

    2005-01-28

    The RHIC polarized H-Jet measures the polarization of the RHIC proton beam via elastic scattering off a nuclear polarized atomic hydrogen beam. The atomic beam is produced by a dissociator, a beam forming system and sextupole magnets. Nuclear polarization is achieved by exchanging occupation numbers of hyperfine states using high frequency transitions. The polarization was measured using a modified form of a Breit-Rabi polarimeter including focusing magnets and another set of high frequency transitions. The sampling of a large part of the beam and low noise electronics made it possible to measure the polarization to a high degree of accuracy in a very short time period (1 min). Using this system, we measured no depolarization of the atomic beam due to the RF fields of the bunched proton beam. Time-of-Flight measurements were done using a fast chopper and a QMA at the position of the RHIC interaction point to determine the areal density of the atomic beam seen by the RHIC beam.

  16. Status of the hydrogen and deuterium atomic beam polarized target for NEPTUN experiment

    NASA Astrophysics Data System (ADS)

    Balandikov, N. I.; Ershov, V. P.; Fimushkin, V. V.; Kulikov, M. V.; Pilipenko, Yu. K.; Shutov, V. B.

    1995-09-01

    NEPTUN-NEPTUN-A is a polarized experiment at Accelerating and Storage Complex (UNK, IHEP) with two internal targets. Status of the atomic beam polarized target that is being developed at the Joint Institute for Nuclear Research, Dubna is presented.

  17. Chaotic dynamics of dilute thermal atom clouds on stationary optical Bessel beams

    NASA Astrophysics Data System (ADS)

    Castañeda, J. A.; Pérez-Pascual, R.; Jáuregui, R.

    2013-07-01

    We characterize the semiclassical dynamics of dilute thermal atom clouds located in three-dimensional optical lattices generated by stationary optical Bessel beams. The dynamics of the cold atoms is explored in the quasi-Hamiltonian regime that arises using laser beams with far-off resonance detuning. Although the transverse structure of Bessel beams exhibits a complex topological structure, it is found that the longitudinal motion along the main propagation axis of the beam is the detonator of a high sensitivity of the atoms' motion to the initial conditions. This effect would not be properly described by bidimensional models. We show that an experimental implementation can be highly simplified by an analysis of the behaviour of the dynamical system under scale transformations. Experimentally feasible signatures of the chaotic dynamics of the atom clouds are also identified.

  18. Summary of informal workshop on state of ion beam facilities for atomic physics research

    SciTech Connect

    Jones, K.W.; Cocke, C.L.; Datz, S.; Kostroun, V.

    1984-11-13

    The present state of ion beam facilities for atomic physics research in the United States is assessed by means of a questionnaire and informal workshop. Recommendations for future facilities are given. 3 refs.

  19. Compact Gamma-Beam Source for Nuclear Security Technologies

    NASA Astrophysics Data System (ADS)

    Gladkikh, P.; Urakawa, J.

    2015-10-01

    A compact gamma-beam source dedicated to the development of the nuclear security technologies by use of the nuclear resonance fluorescence is described. Besides, such source is a very promising tool for novel technologies of the express cargoes inspection to prevent nuclear terrorism. Gamma-beam with the quanta energies from 0.3MeV to 7.2MeV is generated in the Compton scattering of the "green" laser photons on the electron beam with energies from 90MeV to 430MeV. The characteristic property of the proposed gammabeam source is a narrow spectrum (less than 1%) at high average gamma-yield (of 1013γ/s) due to special operation mode.

  20. A virtual source model for Kilo-voltage cone beam CT: Source characteristics and model validation

    SciTech Connect

    Spezi, E.; Volken, W.; Frei, D.; Fix, M. K.

    2011-09-15

    Purpose: The purpose of this investigation was to study the source characteristics of a clinical kilo-voltage cone beam CT unit and to develop and validate a virtual source model that could be used for treatment planning purposes. Methods: We used a previously commissioned full Monte Carlo model and new bespoke software to study the source characteristics of a clinical kilo-voltage cone beam CT (CBCT) unit. We identified the main particle sources, their spatial, energy and angular distribution for all the image acquisition presets currently used in our clinical practice. This includes a combination of two energies (100 and 120 kVp), two filters (neutral and bowtie), and eight different x-ray beam apertures. We subsequently built a virtual source model which we validated against full Monte Carlo calculations. Results: We found that the radiation output of the clinical kilo-voltage cone beam CT unit investigated in this study could be reproduced with a virtual model comprising of two sources (target and filtration cone) or three sources (target, filtration cone and bowtie filter) when additional filtration was used. With this model, we accounted for more than 97% of the photons exiting the unit. Each source in our model was characterised by a origin distribution in both X and Y directions, a fluence map, a single energy spectrum for unfiltered beams and a two dimensional energy spectrum for bowtie filtered beams. The percentage dose difference between full Monte Carlo and virtual source model based dose distributions was well within the statistical uncertainty associated with the calculations ( {+-} 2%, one standard deviation) in all cases studied. Conclusions: The virtual source that we developed is accurate in calculating the dose delivered from a commercial kilo-voltage cone beam CT unit operating with routine clinical image acquisition settings. Our data have also shown that target, filtration cone, and bowtie filter sources needed to be all included in the model

  1. Pulsed rotating supersonic source for merged molecular beams

    NASA Astrophysics Data System (ADS)

    Sheffield, L.; Hickey, M. S.; Krasovitskiy, V.; Rathnayaka, K. D. D.; Lyuksyutov, I. F.; Herschbach, D. R.

    2012-06-01

    We describe a pulsed rotating supersonic beam source, evolved from an ancestral device [M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001)]. The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, cryocooling, and a shutter gate eliminated the main handicap of the original device in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1-0.6 ms (depending on rotor speed) and containing ˜1012 molecules at lab speeds as low as 35 m/s and ˜1015 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, Cl2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.

  2. Pulsed rotating supersonic source for merged molecular beams

    NASA Astrophysics Data System (ADS)

    Sheffield, Les; Hickey, Mark; Krasovitskiy, Vitaliy; Rathnayaka, Daya; Lyuksyutov, Igor; Herschbach, Dudley

    2012-10-01

    We continue the characterization of a pulsed rotating supersonic beam source. The original device was described by M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001). The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at high-speed to shift the molecular velocity distribution downward or upward over a wide range. Here we consider mostly the slowing mode. Introducing a pulsed gas inlet system, and a shutter gate eliminate the main handicap of the original device in which continuous gas flow imposed high background pressure. The new version provides intense pulses, of duration 0.1--0.6 ms (depending on rotor speed) and containing ˜10^12 molecules at lab speeds as low as 35 m/s and ˜10^15 molecules at 400 m/s. Beams of any molecule available as a gas can be slowed (or speeded); e.g., we have produced slow and fast beams of rare gases, O2, NO2, NH3, and SF6. For collision experiments, the ability to scan the beam speed by merely adjusting the rotor is especially advantageous when using two merged beams. By closely matching the beam speeds, very low relative collision energies can be attained without making either beam very slow.

  3. Neutron fan beam source for neutron radiography purpose

    SciTech Connect

    Le Tourneur, P.; Bach, P.; Dance, W. E.

    1999-06-10

    The development of the DIANE neutron radiography system included a sealed-tube neutron generator for this purpose and the optimization of the system's neutron beam quality in terms of divergence and useful thermal neutron yield for each 14-MeV neutron produced. Following this development, the concept of a DIANE fan beam source is herewith introduced. The goal which drives this design is one of economy: by simply increasing the aperture dimension of a conventional DIANE beam in one plane of its collimator axis to a small-angle, fan-shaped output, the useful beam area for neutron radiography would be substantially increased. Thus with the same source, the throughput, or number of objects under examination at any given time, would be augmented significantly. Presented here are the design of this thermal neutron source and the initial Monte Carlo calculations. Taking into account the experience with the conventional DIANE neutron radiography system, these result are discussed and the potential of and interest in such a fan-beam source are explored.

  4. Ferroelectric Plasma Source for Heavy Ion Beam ChargeNeutralization

    SciTech Connect

    Efthimion, Philip C.; Gilson, Erik P.; Grisham, Larry; Davidson,Ronald C.; Yu, Simon; Waldron, William; Logan, B. Grant

    2005-10-01

    Plasmas are employed as a source of unbound electrons for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length {approx} 0.1-1 m would be suitable. To produce one-meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being developed. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source utilizes the ferroelectric ceramic BaTiO{sub 3} to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic, and high voltage ({approx} 1-5 kV) applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long has produced plasma densities of 5 x 10{sup 11} cm{sup -3}. The source was integrated into the previous Neutralized Transport Experiment (NTX), and successfully charge neutralized the K{sup +} ion beam. Presently, the one-meter source is being fabricated. The source is being characterized and will be integrated into NDCX for charge neutralization experiments.

  5. Long Plasma Source for Heavy Ion Beam Charge Neutralization

    SciTech Connect

    Efthimion, P.C.; Gilson, E.P.; Grisham, L.; Davidson, R.C.; Logan, B.G.; Seidl, P.A.; Waldron, W.

    2008-06-01

    Plasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus them to a small spot size and compress their axial length. The plasma source should operate at low neutral pressures and without strong externally-applied fields. To produce long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients have been developed. The source utilizes the ferroelectric ceramic BaTiO{sub 3} to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic material. High voltage ({approx} 8 kV) is applied between the drift tube and the front surface of the ceramics. A BaTiO{sub 3} source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma in the 5 x 10{sup 10} cm{sup -3} density range. The source was integrated into the NDCX device for charge neutralization and beam compression experiments, and yielded current compression ratios {approx} 120. Present research is developing multi-meter-long and higher density sources to support beam compression experiments for high energy density physics applications.

  6. Fractional adiabatic passage in two-level systems: Mirrors and beam splitters for atomic interferometry

    SciTech Connect

    Bateman, James; Freegarde, Tim

    2007-07-15

    Atom interferometers require atom mirrors and beam splitters that can maintain high fidelity even when experimental parameters vary from the ideal. We address the use of chirped laser pulses to provide such elements via rapid adiabatic passage, and present a prescription for practical pulses that offer controlled adiabaticity throughout. Full- and half-adiabatic pulses, providing mirrors and beam splitters, respectively, are derived, and the latter examined for robustness and suitability for experimental implementations.

  7. Trapping a single atom in a blue detuned optical bottle beam trap.

    PubMed

    Xu, Peng; He, Xiaodong; Wang, Jin; Zhan, Mingsheng

    2010-07-01

    We demonstrate trapping a single rubidium atom in a blue detuned optical bottle beam trap. The trap was formed by a strongly focused blue detuned laser beam, which passes through a computer-generated circular pi phase hologram displayed on a spatial light modulator. Single atoms were loaded from a magneto-optical trap and stored in the optical trap for several seconds. PMID:20596181

  8. High-flux source of low-energy neutral beams using reflection of ions from metals

    NASA Technical Reports Server (NTRS)

    Cuthbertson, John W.; Motley, Robert W.; Langer, William D.

    1992-01-01

    Reflection of low-energy ions from surfaces can be applied as a method of producing high-flux beams of low-energy neutral particles, and is an important effect in several areas of plasma technology, such as in the edge region of fusion devices. We have developed a beam source based on acceleration and reflection of ions from a magnetically confined coaxial RF plasma source. The beam provides a large enough flux to allow the energy distribution of the reflected neutrals to be measured despite the inefficiency of detection, by means of an electrostatic cylindrical mirror analyzer coupled with a quadrupole mass spectrometer. Energy distributions have been measured for oxygen, nitrogen, and inert gas ions incident with from 15 to 70 eV reflected from amorphous metal surfaces of several compositions. For ions of lighter atomic mass than the reflecting metal, reflected beams have peaked energy distributions; beams with the peak at 4-32 eV have been measured. The energy and mass dependences of the energy distributions as well as measurements of absolute flux, and angular distribution and divergence are reported. Applications of the neutral beams produced are described.

  9. Means for obtaining a metal ion beam from a heavy-ion cyclotron source

    DOEpatents

    Hudson, E.D.; Mallory, M.L.

    1975-08-01

    A description is given of a modification to a cyclotron ion source used in producing a high intensity metal ion beam. A small amount of an inert support gas maintains the usual plasma arc, except that it is necessary for the support gas to have a heavy mass, e.g., xenon or krypton as opposed to neon. A plate, fabricated from the metal (or anything that can be sputtered) to be ionized, is mounted on the back wall of the ion source arc chamber and is bombarded by returning energetic low-charged gas ions that fail to cross the initial accelerating gap between the ion source and the accelerating electrode. Some of the atoms that are dislodged from the plate by the returning gas ions become ionized and are extracted as a useful beam of heavy ions. (auth)

  10. Plasma-formed hyperthermal atomic beams for use in thin film fabrication

    NASA Astrophysics Data System (ADS)

    Gilson, E. P.; Cohen, S. A.; Berlinger, B.; Chan, W.

    2013-10-01

    Enhancing the surface mobility of adsorbents during thin-film growth processes is important for creating certain high-quality thin films. Under the auspices of a DARPA program to develop methods for supplying momentum to adsorbates during thin-film formation without using bulk heating, a hyperthermal atomic beam (HAB) was generated and directed at silicon surfaces with patterned coatings of pentacene, gold, and other surrogates for adsorbents relevant to various thin-film coatings. The HAB was created when the plasma from a helicon plasma source struck a tungsten neutralizer plate and was reflected as neutrals. Time averaged HAB fluxes 100 times greater than in previous PPPL HAB sources have been generated. The effect of the HAB on the patterned coatings was measured using atomic force microscopy (AFM). Results are presented on the flux and energy of the HAB for various system pressures, magnetic fields, and neutralizer biases. AFM measurements of the surface topology demonstrate that the HAB energy, species, and integrated flux are all important factors in altering surface mobility. This research is supported by the U.S. Defense Advanced Research Projects Agency.