WorldWideScience

Sample records for atomic source icp-rims

  1. Laser controlled atom source for optical clocks

    Science.gov (United States)

    Kock, Ole; He, Wei; Świerad, Dariusz; Smith, Lyndsie; Hughes, Joshua; Bongs, Kai; Singh, Yeshpal

    2016-11-01

    Precision timekeeping has been a driving force in innovation, from defining agricultural seasons to atomic clocks enabling satellite navigation, broadband communication and high-speed trading. We are on the verge of a revolution in atomic timekeeping, where optical clocks promise an over thousand-fold improvement in stability and accuracy. However, complex setups and sensitivity to thermal radiation pose limitations to progress. Here we report on an atom source for a strontium optical lattice clock which circumvents these limitations. We demonstrate fast (sub 100 ms), cold and controlled emission of strontium atomic vapours from bulk strontium oxide irradiated by a simple low power diode laser. Our results demonstrate that millions of strontium atoms from the vapour can be captured in a magneto-optical trap (MOT). Our method enables over an order of magnitude reduction in scale of the apparatus. Future applications range from satellite clocks testing general relativity to portable clocks for inertial navigation systems and relativistic geodesy.

  2. Cold Atom Source Containing Multiple Magneto-Optical Traps

    Science.gov (United States)

    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.

  3. Stable atomic hydrogen possible application in intense polarized sources

    CERN Document Server

    Niinikoski, T O; Rieubland, Jean Michel

    1982-01-01

    The authors briefly review the status of spin-polarized atomic hydrogen and discuss a possible way of extending the present limit of density. Pulse extraction of stabilized atoms by millimetre wave is proposed as a means of producing polarized atomic beams of uniform velocity and low divergence. It is speculated that these atoms could be used either as jet targets of a conventional type, or as a stored atomic beam target by injecting them into a storage ring intersecting with an accelerator beam. When used in a polarized ion source, the high density of the atomic beam could possibly also improve the ionizer efficiency.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Compact high-flux source of cold sodium atoms

    Science.gov (United States)

    Lamporesi, G.; Donadello, S.; Serafini, S.; Ferrari, G.

    2013-06-01

    We present a compact source of cold sodium atoms suitable for the production of quantum degenerate gases and versatile for a multi-species experiment. The magnetic field produced by permanent magnets allows to simultaneously realize a Zeeman slower and a two-dimensional magneto-optical trap (MOT) within an order of magnitude smaller length than standard sodium sources. We achieve an atomic flux exceeding 4 × 109 atoms/s loaded in a MOT, with a most probable longitudinal velocity of 20 m/s, and a brightness larger than 2.5 × 1012 atoms/s/sr. This atomic source allows us to produce pure Bose-Einstein condensates with more than 107 atoms and a background pressure limited lifetime of 5 min.

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

    Science.gov (United States)

    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.

  7. Characterization of an atomic hydrogen source for charge exchange experiments

    Science.gov (United States)

    Leutenegger, M. A.; Beiersdorfer, P.; Betancourt-Martinez, G. L.; Brown, G. V.; Hell, N.; Kelley, R. L.; Kilbourne, C. A.; Magee, E. W.; Porter, F. S.

    2016-11-01

    We characterized the dissociation fraction of a thermal dissociation atomic hydrogen source by injecting the mixed atomic and molecular output of the source into an electron beam ion trap containing highly charged ions and recording the x-ray spectrum generated by charge exchange using a high-resolution x-ray calorimeter spectrometer. We exploit the fact that the charge exchange state-selective capture cross sections are very different for atomic and molecular hydrogen incident on the same ions, enabling a clear spectroscopic diagnostic of the neutral species.

  8. Narrow linewidth single laser source system for onboard atom interferometry

    CERN Document Server

    Theron, Fabien; Renon, Geoffrey; Bidel, Yannick; Zahzam, Nassim; Cadoret, Malo; Bresson, Alexandre

    2014-01-01

    We present an original compact and robust laser system for atom interferometry based on a frequency-doubled telecom laser. Thanks to an original stabilization architecture on a saturated absorption, we obtain a frequency agile laser system allowing fast tuning of the laser frequency over 1 GHz in few ms using only a single laser source. The different laser frequencies used for atom interferometry are created by changing dynamically the frequency of the laser and by creating sidebands using a phase modulator. 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 compact, much less sensitive to vibrations and thermal fluctuations. This source provides spectral linewidth below 2.5 kHz required for precision atom interferometry, and particularly for an high performance atomic inertial sensor.

  9. Dual-wavelength laser source for onboard atom interferometry

    CERN Document Server

    Ménoret, Vincent; Stern, Guillaume; Zahzam, Nassim; Battelier, Baptiste; Bresson, Alexandre; Landragin, Arnaud; Bouyer, Philippe

    2011-01-01

    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.

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

    Science.gov (United States)

    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.

  11. Narrow linewidth single laser source system for onboard atom interferometry

    Science.gov (United States)

    Theron, Fabien; Carraz, Olivier; Renon, Geoffrey; Zahzam, Nassim; Bidel, Yannick; Cadoret, Malo; Bresson, Alexandre

    2015-01-01

    A compact and robust laser system for atom interferometry based on a frequency-doubled telecom laser is presented. Thanks to the original stabilization architecture on a saturated absorption setup, we obtain a frequency agile laser system allowing fast tuning of the laser frequency over 1 GHz in few ms using a single laser source. The different laser frequencies used for atom interferometry are generated by changing dynamically the frequency of the laser and by creating sidebands using a phase modulator. A laser system for Rubidium 87 atom interferometry using only one laser source based on a frequency-doubled telecom fiber bench is then built. 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 compact and much less sensitive to vibrations and thermal fluctuations. This source provides spectral linewidth below 2.5 kHz, which is required for precision atom interferometry and particularly for a high performance atomic inertial sensor.

  12. Laser sources for precision spectroscopy on atomic strontium.

    Science.gov (United States)

    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.

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

    CERN Document Server

    Rudolph, Jan; 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

    2015-01-01

    Quantum sensors based on coherent matter-waves are precise measurement devices whose ultimate accuracy is achieved with Bose-Einstein condensates (BEC) 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 technological challenge. Here we report on the realization of a miniaturized setup, generating a flux of $4 \\times 10^5$ quantum degenerate $^{87}$Rb atoms every 1.6 s. Ensembles of $1 \\times 10^5$ 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 experiments while offering significantly higher repetition rates. The compact and robust design allows for mobile operation in a variety of...

  14. Microwave discharge as a remote source of neutral oxygen atoms

    Directory of Open Access Journals (Sweden)

    Gregor Primc

    2011-06-01

    Full Text Available The late flowing afterglow of an oxygen plasma was used as a remote source of neutral oxygen atoms. Plasma was created via a microwave discharge in a narrow quartz glass tube with an inner diameter of 6 mm at powers between 50 W and 300 W. The tube was connected to a wider perpendicular tube with an inner diameter of 36 mm. The density of neutral oxygen atoms was measured in the wide tube about 70 cm from the discharge using a classical nickel catalytic probe. The oxygen atom density as a function of gas pressure had a well-defined maximum. The oxygen atom density can be as large as 11 × 1020 m-3. At the lowest power tested (50 W, the maximum was obtained at a pressure of about 30 Pa. However, at higher powers, the maximum shifted to higher pressures. As a result, at 300 W the maximum appeared at 60 Pa. The results can be explained through collision phenomena in gas phase and surfaces in both discharge and flowing afterglow regions, and strong pressure gradients along the narrow tube.

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

    Science.gov (United States)

    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+.

  16. Biprism Electron Interferometry with a Single Atom Tip Source

    CERN Document Server

    Schütz, Georg; Pooch, Andreas; Meier, Simon; Schneeweiss, Philipp; Rauschenbeutel, Arno; Günther, Andreas; Chang, Wei-Tse; Hwang, Ing-Shouh; Stibor, Alexander

    2013-01-01

    Experiments with electron or ion matter waves require a coherent, monochromatic and long-term stable source with high brightness. These requirements are best fulfilled by single atom tip (SAT) field emitters. The performance of an iridium covered W(111) SAT is demonstrated and analyzed for electrons in a biprism interferometer. Furthermore we characterize the emission of the SAT in a separate field electron and field ion microscope and compare it with other emitter types. A new method is presented to fabricate the electrostatic charged biprism wire that separates and combines the matter wave. In contrast to other biprism interferometers the source and the biprism size are well defined within a few nanometers. The setup has direct applications in ion interferometry and Aharonov-Bohm physics.

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

    Science.gov (United States)

    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 10(6) 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 (24)Mg(+).

  18. Creation and recovery of a W(111) single atom gas field ion source.

    Science.gov (United States)

    Pitters, Jason L; Urban, Radovan; Wolkow, Robert A

    2012-04-21

    Tungsten single atom tips have been prepared from a single crystal W(111) oriented wire using the chemical assisted field evaporation and etching method. Etching to a single atom tip occurs through a symmetric structure and leads to a predictable last atom unlike etching with polycrystalline tips. The single atom tip formation procedure is shown in an atom by atom removal process. Rebuilds of single atom tips occur on the same crystalline axis as the original tip such that ion emission emanates along a fixed direction for all tip rebuilds. This preparation method could be utilized and developed to prepare single atom tips for ion source development.

  19. Feasibility of filter atomization in high-resolution continuum source atomic absorption spectrometry

    Science.gov (United States)

    Heitmann, Uwe; Becker-Ross, Helmut; Katskov, Dmitri

    2006-03-01

    A prototype spectrometer for high-resolution continuum source atomic absorption spectrometry (HR-CS AAS), built at ISAS Berlin, Germany, was combined with a graphite filter atomizer (GFA), earlier developed at TUT, Pretoria, South Africa. The furnace and auto-sampler units from a commercial AA spectrometer, model AAS vario 6 (Analytik Jena AG, Jena, Germany), were employed in the instrument. Instead of conventional platform tube, the GFA was used to provide low measurement susceptibility to interferences and short determination cycle. The GFA was modified according to the design of the furnace unit and optimal physical parameters of its components (filter and collector) found. Afterwards, optimal GFA was replicated and tested to outline analytical performances of the HR-CS GFA AA spectrometer in view of prospects of multi-element analysis. In particular, reproducibility of performances, repeatability of analytical signals, lifetime, temperature limit and duration of the measurement cycle were examined, and elements available for determination justified. The results show that the peak area of the atomic absorption signal is reproduced in various GFA copies within ± 4% deviation range. The GFA can stand temperatures of 2800 °C with 6 s hold time for 55 temperature cycles, and 2700 °C (8 s) for about 200 cycles. Only the external tube is prone to destruction while the filter and collector do not show any sign of erosion caused by temperature or aggressive matrix. Analytical signals are affected insignificantly by tube aging. Repeatability of the peak area remains within 1.1-1.7% RSD over more than hundred determination cycles. Peak areas are proportional to the sample volume of injected organic and inorganic liquids up to at least 50 μL. The drying stage is combined with hot sampling and cut down to 15-20 s. The list of metals available for determination with full vapor release includes Al, Co, Cr, Ni, Pt as well as more volatile metals. Characteristic masses at

  20. Noncontact atomization of droplets using an aerial ultrasonic source with two vibrating plates

    Science.gov (United States)

    Endo, Arisa; Yanagimoto, Miduki; Asami, Takuya; Miura, Hikaru

    2015-07-01

    For use in mass spectrometry, we investigated the noncontact atomization of droplets using a rectangular transverse vibrating plate ultrasonic source. To determine the atomization properties of the ultrasonic source, we examined the sound pressure distribution of the standing wave acoustic field formed and observed the behavior of the atomized particles in the acoustic field. We determined the relationship between sound pressure and the conditions and location where atomization occurs with the variations in droplet surface tension and viscosity using three different compounds: water, ethanol, and glycerin. Furthermore, we clarifies the distribution of particle diameters in atomized water.

  1. Multi-channel tunable source for atomic sensors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR will establish the feasibility of developing compact, robust, integrated components suitable for atomic interferometry. AdvR's design is enabled by...

  2. Laser Source for Atomic Gravity Wave Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop an Atom Interferometry-based gravity wave detector (vs Optical Interferometry). Characterize a high power laser. Use Goddard Space Flight Center Mission...

  3. Loading of a fountain clock with an enhanced Low-Velocity Intense Source of atoms

    CERN Document Server

    Dobrev, Georgi; Weyers, Stefan

    2016-01-01

    We present experimental work for improved atom loading in the optical molasses of a caesium fountain clock, employing a low-velocity intense source of atoms (LVIS) [Lu et al., Phys. Rev. Lett. 77, 3331 (1996)], which we modified by adding a "dark" state pump laser. With this modification the atom source has a mean flux of $4 \\times 10^{8}$ atoms/s at a mean atom velocity of $8.6$ m/s. Compared to fountain operation using background gas loading, we achieved a significant increase of the loaded and detected atom number by a factor of 40. Operating the fountain clock with a total number of detected atoms $N_{\\mathrm{at}}=2.9 \\times 10^6$ in the quantum projection noise-limited regime, a frequency instability $\\sigma_y\\left(1\\text{s}\\right)=2.7 \\times 10^{-14}$ was demonstrated.

  4. A New ECR Ion Source for Atomic Physics Research at IMP

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new Electron Cyclotron Resonance (ECR) ion source (LECR3-Lanzhou Electron Cyclotron Resonance ion source No.3) was constructed this year. The main purpose of this source is to provide highly charged ion beams for atomic physics and surface physics research. The design of this ion source is based on the IMP 14.5 GHz ECR ion source (LECR2-Lanzhou Electron Cyclotron Resonance ion source No.2) with double RF heating

  5. Alternate Funding Sources for the International Atomic Energy Agency

    Energy Technology Data Exchange (ETDEWEB)

    Toomey, Christopher; Wyse, Evan T.; Kurzrok, Andrew J.; Swarthout, Jordan M.

    2012-09-04

    Since 1957, the International Atomic Energy Agency (IAEA) has worked to ensure the safe and responsible promotion of nuclear technology throughout the world. The IAEA operates at the intersection of the Nuclear Nonproliferation Treaty’s (NPT) fourth and third articles, which guarantee Parties to the Treaty the right to peaceful uses of nuclear technology, provided those activities are placed under safeguards verified by the IAEA. However, while the IAEA has enjoyed substantial success and prestige in the international community, there is a concern that its resources are being stretched to a point where it may no longer be possible to execute its multifaceted mission in its entirety. As noted by the Director General (DG) in 2008, demographics suggest that every aspect of the IAEA’s operations will be in higher demand due to increasing reliance on non-carbon-based energy and the concomitant nonproliferation, safety, and security risks that growth entails. In addition to these nuclear energy concerns, the demand for technical developmental assistance in the fields of food security, resource conservation, and human health is also predicted to increase as the rest of the world develops. Even with a 100% value-for-money rating by the U.S. Office of Management and Budget (OMB) and being described as an “extraordinary bargain” by the United Nations Secretary-General’s High-level Panel on Threats, Challenges and Change, real budget growth at the Agency has been limited to zero-real growth for a better part of the last two decades. Although the 2012 regular budget (RB) received a small increase for most programs, the 2013 RB has been set at zero-real growth. As a result, the IAEA has had to defer infrastructure investments, which has hindered its ability to provide the public goods its Members seek, decreased global security and development opportunities, and functionally transformed the IAEA into a charity, dependent on extrabudgetary (EB) contributions to sustain

  6. Characterization of a velocity-tunable 87Rb cold atomic source with a high-speed imaging technology

    Institute of Scientific and Technical Information of China (English)

    Feng Yan-Ying; Zhu Chang-Xing; Wang Xiao-Jia; Xue Hong-Bo; Ye Xiong-Ying; Zhou Zhao-Ying

    2009-01-01

    This paper has developed and characterized a method to produce a velocity-tunable 87Rb cold atomic source for atomic interferometry application.Using a high speed fluorescence imaging technology,it reports that the dynamic process of the atomic source formation is observed and the source performances including the flux and the initial velocity axe characterized.A tunable atomic source with the initial velocity of 1.4~2.6 m/s and the atomic source flux of 2×108~6×109 atoms/s has been obtained with the built experimental setup.

  7. Optical Pumping of Metastable Helium Atoms in Polarized Electron Sources

    Science.gov (United States)

    Brissaud, I.

    1995-04-01

    In this paper we present a comparison between the Orsay and Rice University polarized electron sources. Different explanations of the polarization degradation are discussed for the two cases. For the Rice source radiation, trapping can account for the observed reduction in polarization because of the high absorption cross sections associated with the D1 transition. Some improvements are proposed that might increase the electron polarization.

  8. Optical Pumping of Metastable Helium Atoms in Polarized Electron Sources

    OpenAIRE

    1995-01-01

    In this paper we present a comparison between the Orsay and Rice University polarized electron sources. Different explanations of the polarization degradation are discussed for the two cases. For the Rice source radiation, trapping can account for the observed reduction in polarization because of the high absorption cross sections associated with the D1 transition. Some improvements are proposed that might increase the electron polarization.

  9. A Simulator for Producing of High Flux Atomic Oxygen Beam by Using ECR Plasma Source

    Institute of Scientific and Technical Information of China (English)

    Shuwang DUO; Meishuan LI; Yaming ZHANG

    2004-01-01

    In order to study the atomic oxygen corrosion of spacecraft materials in low earth orbit environment, an atomic oxygen simulator was established. In the simulator, a 2.45 GHz microwave source with maximum power of 600 W was launched into the circular cavity to generate ECR (electron cyclotron resonance) plasma. The oxygen ion beam moved onto a negatively biased Mo plate under the condition of symmetry magnetic mirror field confine, then was neutralized and reflected to form oxygen atom beam. The properties of plasma density, electron temperature, plasma space potential and ion incident energy were characterized. The atomic oxygen beam flux was calibrated by measuring the mass loss rate of Kapton during the atomic 5~30 eV and a cross section of φ80 mm could be obtained under the operating pressure of 10-1~10-3 Pa. Such a high flux source can provide accelerated simulation tests of materials and coatings for space applications.

  10. A cost-effective high-flux source of cold ytterbium atoms

    Science.gov (United States)

    Song, Bo; Zou, Yueyang; Zhang, Shanchao; Cho, Chang-woo; Jo, Gyu-Boong

    2016-10-01

    We report a cost-effective way to prepare high-flux slow ytterbium atoms with extremely low-power 399-nm light suitable for the production of quantum degenerate ytterbium gases. By collimating an atomic beam through an array of micro-capillary tubes, we obtain a bright atomic beam through the Zeeman slower operating at low light power of only 15 mW for the source. We achieve the loading rate of 2 × 107 s-1 into the intercombination magneto-optical trap (MOT) and a sufficient steady-state MOT atom number of 2 × 108 for 174Yb atoms. Our apparatus highlights an efficient method to obtain slow ytterbium atoms using a simple low-power 399-nm laser system.

  11. Development of Laser Light Sources for Trapping Radioactive Francium Atoms Toward Tests of Fundamental Symmetries

    Science.gov (United States)

    Harada, Ken-ichi; Ezure, Saki; Hayamizu, Tomohiro; Kato, Ko; Kawamura, Hirokazu; Inoue, Takeshi; Arikawa, Hiroshi; Ishikawa, Taisuke; Aoki, Takahiro; Uchiyama, Aiko; Itoh, Masatoshi; Ando, Shun; Aoki, Takatoshi; Hatakeyama, Atsushi; Hatanaka, Kichiji; Imai, Kenichi; Murakami, Tetsuya; Shimizu, Yasuhiro; Sato, Tomoya; Wakasa, Tomotsugu; Yoshida, Hidetomo P.; Sakemi, Yasuhiro

    We have developed laser light sources and a magneto-optical trap system for cooling and trapping radioactive francium (Fr) atoms. Because Fr is the heaviest alkali element, a Fr atom exhibits high sensitivity to symmetry violation effects such as atomic parity nonconservation (APNC) and the electron electric dipole moment (eEDM). A laser cooling and trapping technique reduces the systematic errors due to the Doppler effect and the motion-induced magnetic field effect caused by the velocity of atoms. Thus, optically cooled and trapped Fr atoms are among a few promising candidates considered for APNC and eEDM measurements. Frequency stabilization of laser light is required for any stable measurement involving trapped radioactive atoms, including Fr. Since the hyperfine splitting in iodine molecules (127I2) is close to the resonance frequency of the Fr D2 line, we performed frequency modulation spectroscopy of hyperfine structures of I2.

  12. Integrated MEMS mass sensor and atom source for a ``Fab on a Chip''

    Science.gov (United States)

    Han, Han; Imboden, Matthias; Stark, Thomas; Bishop, David

    2014-03-01

    ``Fab on a Chip'' is a new concept suggesting that the semiconductor fabrication facility can be integrated into a single silicon chip for nano-manufacturing. Such a chip contains various MEMS devices which can work together, operating in a similar way as a conventional fab does, to fabricate nano-structures. Here we present two crucial ``Fab on a chip'' components: the MEMS mass sensor and atomic evaporation source. The mass sensor is essentially a parallel plate capacitor with one suspended plate. When incident atoms deposit on the suspended plate, the mass change of the plate can be measured by detecting the resonant frequency shift. Using the mass sensor, a mass resolution of 3 fg is achieved. The MEMS evaporation source consists of a polysilicon plate suspended by two electrical leads with constrictions. By resistively heating the plate, this device works as a tunable atom flux source. By arranging many of these devices into an array, one can build a multi-element atom evaporator. The mass sensor and atom source are integrated so that the mass sensor is used to monitor and characterize the atomic flux. A material source and a sensor to monitor the fabrication are two integral components for our ``Fab on a Chip.''

  13. Sparse cortical source localization using spatio-temporal atoms.

    Science.gov (United States)

    Korats, Gundars; Ranta, Radu; Le Cam, Steven; Louis-Dorr, Valérie

    2015-01-01

    This paper addresses the problem of sparse localization of cortical sources from scalp EEG recordings. Localization algorithms use propagation model under spatial and/or temporal constraints, but their performance highly depends on the data signal-to-noise ratio (SNR). In this work we propose a dictionary based sparse localization method which uses a data driven spatio-temporal dictionary to reconstruct the measurements using Single Best Replacement (SBR) and Continuation Single Best Replacement (CSBR) algorithms. We tested and compared our methods with the well-known MUSIC and RAP-MUSIC algorithms on simulated realistic data. Tests were carried out for different noise levels. The results show that our method has a strong advantage over MUSIC-type methods in case of synchronized sources.

  14. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  15. Stimulated Raman Adiabatic Passage for Improved Performance of a Cold Atom Electron and Ion Source

    CERN Document Server

    Sparkes, B M; Taylor, R J; Spiers, R W; McCulloch, A J; Scholten, R E

    2016-01-01

    We experimentally implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold atom electron and ion source, leading to a peak efficiency of 85%, a 1.7 times improvement in excitation probability relative to incoherent pulsed-laser excitation. Using streak measurements and pulsed electric field ionization of the Rydberg atoms we demonstrate electron bunches with duration of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, while using coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single ion source.

  16. Single-Shot Electron Diffraction using a Cold Atom Electron Source

    CERN Document Server

    Speirs, Rory W; Nugent, Keith A; Sparkes, Benjamin M; Scholten, Robert E

    2015-01-01

    Cold atom electron sources are a promising alternative to traditional photocathode sources for use in ultrafast electron diffraction due to greatly reduced electron temperature at creation, and the potential for a corresponding increase in brightness. Here we demonstrate single-shot, nanosecond electron diffraction from monocrystalline gold using cold electron bunches generated in a cold atom electron source. The diffraction patterns have sufficient signal to allow registration of multiple single-shot images, generating an averaged image with significantly higher signal-to-noise ratio than obtained with unregistered averaging. Reflection high-energy electron diffraction (RHEED) was also demonstrated, showing that cold atom electron sources may be useful in resolving nanosecond dynamics of nanometre scale near-surface structures.

  17. A surface-patterned chip as a strong source of ultracold atoms for quantum technologies

    Science.gov (United States)

    Nshii, C. C.; Vangeleyn, M.; Cotter, J. P.; Griffin, P. F.; Hinds, E. A.; Ironside, C. N.; See, P.; Sinclair, A. G.; Riis, E.; Arnold, A. S.

    2013-05-01

    Laser-cooled atoms are central to modern precision measurements. They are also increasingly important as an enabling technology for experimental cavity quantum electrodynamics, quantum information processing and matter-wave interferometry. Although significant progress has been made in miniaturizing atomic metrological devices, these are limited in accuracy by their use of hot atomic ensembles and buffer gases. Advances have also been made in producing portable apparatus that benefits from the advantages of atoms in the microkelvin regime. However, simplifying atomic cooling and loading using microfabrication technology has proved difficult. In this Letter we address this problem, realizing an atom chip that enables the integration of laser cooling and trapping into a compact apparatus. Our source delivers ten thousand times more atoms than previous magneto-optical traps with microfabricated optics and, for the first time, can reach sub-Doppler temperatures. Moreover, the same chip design offers a simple way to form stable optical lattices. These features, combined with simplicity of fabrication and ease of operation, make these new traps a key advance in the development of cold-atom technology for high-accuracy, portable measurement devices.

  18. Error sources in atomic force microscopy for dimensional measurements: Taxonomy and modeling

    DEFF Research Database (Denmark)

    Marinello, F.; Voltan, A.; Savio, E.

    2010-01-01

    This paper aimed at identifying the error sources that occur in dimensional measurements performed using atomic force microscopy. In particular, a set of characterization techniques for errors quantification is presented. The discussion on error sources is organized in four main categories......: scanning system, tip-surface interaction, environment, and data processing. The discussed errors include scaling effects, squareness errors, hysteresis, creep, tip convolution, and thermal drift. A mathematical model of the measurement system is eventually described, as a reference basis for errors...

  19. Stimulated Raman adiabatic passage for improved performance of a cold-atom electron and ion source

    Science.gov (United States)

    Sparkes, B. M.; Murphy, D.; Taylor, R. J.; Speirs, R. W.; McCulloch, A. J.; Scholten, R. E.

    2016-08-01

    We implement high-efficiency coherent excitation to a Rydberg state using stimulated Raman adiabatic passage in a cold-atom electron and ion source. We achieve an efficiency of 60% averaged over the laser excitation volume with a peak efficiency of 82%, a 1.6 times improvement relative to incoherent pulsed-laser excitation. Using pulsed electric field ionization of the Rydberg atoms we create electron bunches with durations of 250 ps. High-efficiency excitation will increase source brightness, crucial for ultrafast electron diffraction experiments, and coherent excitation to high-lying Rydberg states could allow for the reduction of internal bunch heating and the creation of a high-speed single-ion source.

  20. Solar ions in the heliosheath: a possible new source of heavy neutral atoms

    CERN Document Server

    Grzedzielski, S; Bzowski, M; Izmodenov, V

    2006-01-01

    We show that multiply ionized coronal C, N, O, Mg, Si, S ions carried by the solar wind and neutralized by consecutive electron captures from neutral interstellar atoms constitute an important new source of neutral atoms in the inner heliosheath, with energies up to ~ 1 keV/n. In the model we developed, the heavy ions are treated as test particles carried by hydrodynamic plasma flow (with a Monte-Carlo description of interstellar neutrals) and undergoing all relevant atomic processes determining the evolution of all charge-states of considered species (radiative and dielectronic recombination, charge exchange, photo-, and electron impact ionization). The total strength of the source is from ~10^6 g/s for S to ~10^8 g/s for O, deposited as neutrals below the heliopause. These atoms should provide, as they drift to supersonic wind region, important sources of PUIs and eventually ACRs, especially for species that are excluded from entering the heliosphere because of their ionization in the LISM. The expected cor...

  1. Interfacing transitions of different alkali atoms and telecom bands using one narrowband photon pair source

    CERN Document Server

    Schunk, Gerhard; Strekalov, Dmitry V; Förtsch, Michael; Sedlmeir, Florian; Schwefel, Harald G L; Göbelt, Manuela; Christiansen, Silke; Leuchs, Gerd; Marquardt, Christoph

    2015-01-01

    Photon-atom coupling, in particular for proposed quantum repeater schemes, requires pure and versatile sources of quantum light. Here we demonstrate coupling to alkali dipole transitions in the near-infrared with a tunable source of photon pairs generated via spontaneous parametric down-conversion in a whispering-gallery mode resonator (WGMR). We have developed novel wavelength tuning mechanisms, which allow for a coarse step-wise central wavelength tuning from 790 nm to 1630 nm as well as continuous tuning with MHz resolution. We demonstrate the compatibility of our source with atomic transitions, such as the D1 line of rubidium at 795 nm (idler at 1608 nm) and cesium at 895\\,nm (idler at 1312 nm). At the cesium D1 transition, we exemplarily show a continuous scanning of the signal wavelength over the Doppler-broadened absorption line, and finally a heralded single photon spectroscopy of the atomic decay. Providing this flexibility in connecting various atomic transitions with telecom wavelengths, we demonst...

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

    Science.gov (United States)

    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

  3. A compact 3.5-dB squeezed light source with atomic ensembles

    CERN Document Server

    Bao, Guzhi; Chen, Bing; Guo, Jinxian; Shen, Heng; Chen, Liqing; Zhang, Weiping

    2015-01-01

    We reported a compact squeezed light source consisting of an diode laser near resonant on 87Rb optical D1 transition and an warm Rubidium vapor cell. The -4dB vacuum squeezing at 795 nm via nonlinear magneto-optical rotation was observed when applying the magnetic field orthogonal to the propagation direction of the light beam. This compact squeezed light source can be potentially utilized in the quantum information protocols such as quantum repeater and memory, and quantum metrology such as atomic magnetometer.

  4. An all-solid-state laser source at 671 nm for cold atom experiments with lithium

    CERN Document Server

    Eismann, Ulrich; Canalias, Carlota; Zukauskas, Andrius; Trénec, Gérard; Vigué, Jacques; Chevy, Frédéric; Salomon, Christophe

    2011-01-01

    We present an all solid-state narrow line-width laser source emitting $670\\,\\mathrm{mW}$ output power at $671\\,\\mathrm{nm}$ delivered in a diffraction-limited beam. The source is based on a frequency-doubled diode-end-pumped ring laser operating on the ${^4F}_{3/2} \\rightarrow {^4I}_{13/2}$ transition in Nd:YVO$_4$. By using periodically-poled potassium titanyl phosphate (ppKTP) in an external build-up cavity, doubling efficiencies of up to 86% are obtained. Tunability of the source over $100\\,\\rm GHz$ is accomplished. We demonstrate the suitability of this robust frequency-stabilized light source for laser cooling of lithium atoms. Finally a simplified design based on intra-cavity doubling is described and first results are presented.

  5. Low-resolution continuum source simultaneous multi-element electrothermal atomic absorption spectrometry: steps into practice

    Energy Technology Data Exchange (ETDEWEB)

    Katskov, Dmitri, E-mail: katskovda@tut.ac.za

    2015-03-01

    The theory and practical problems of continuum source simultaneous multi-element electrothermal atomic absorption spectrometry (SMET AAS) are discussed by the example of direct analysis of underground water. The experimental methodology is based on pulse vaporization of the sample in a fast heated graphite tube and measurement of transient absorption of continuum spectrum radiation from D{sub 2} and Xe lamps within 200–400 nm wavelengths range with a low resolution spectral instrument and linear charge-coupled device. The setup permits the acquisition of 200 spectra during 1 s atomization pulse. Respective data matrix absorbance vs wavelength/time is employed for the quantification of elements in the sample. The calculation algorithm developed includes broad band and continuum background correction, linearization of function absorbance vs. concentration of atomic vapor and integration of thus modified absorbance at the resonance lines of the elements to be determined. Practical application shows that the method can be employed for the direct simultaneous determination of about 20 elements above microgram per liter level within 3–5 orders of the magnitude concentration range. The investigated sources of measurement errors are mainly associated with the atomization and vapor transportation problems, which are aggravated for the simultaneous release of major and minor sample constituents. Respective corrections concerning the selection of analytical lines, optimal sampling volume, matrix modification and cleaning of the atomizer have been introduced in the SMET AAS analytical technology. Under the optimized experimental conditions the calibration curves in Log-Log coordinates for all the investigated analytes in the single or multi-element reference solutions are approximated by the first order equations. The use of these equations as permanent characteristics of the setup enables instant quantification of Al, Ca, Co, Cr, Cu, Fe, Mg, Mn and Ni in the underground

  6. Nanoscale displacement of the image of an atomic source of radiation

    Institute of Scientific and Technical Information of China (English)

    Xin Li; Jie Shu; Henk F. Arnoldus

    2009-01-01

    Light emitted by an atomic source of radiation appears to travel along a straight line (ray) from the location of the source to the observer in the far field. However, when the energy flow pattern of the radiation is resolved with an accuracy better than an optical wavelength, it turns out that the field lines are usually curved. We consider electric dipole radiation, a prime example of which is the radiation emitted by an atom during an electronic transition, and we show that the field lines of energy flow are in general curves. Near the location of the dipole, the field lines exhibit a vortex structure, and in the far field they approach a straight line. The spatial extension of the vortex in the optical near field is of nanoscale dimension. Due to the rotation of the field lines near the source, the asymptotic limit of a field line is not exactly in the radially outward direction and as a consequence, the image in the far field is slightly shifted. This sub-wavelength displacement of the image of the source should be amenable to experimental observation with contemporary nanoscale-precision techniques.

  7. A=225 implantation for $^{221}$Fr source for TRIUMF atom trap

    CERN Multimedia

    The FrPNC Collaboration is mounting an atom trap for parity violation experiments and precision spectroscopy on francium atoms at TRIUMF's ISAC facility. We would like to use ISOLDE's capability of simultaneously implanting A=225 (while another experiment runs online) to make a long-lived source feeding $^{221}$Fr for tests of the trap. $^{225}$Ra $\\beta$-decays to $^{225}$Ac, which then $\\alpha$-decays, producing 100 keV $^{221}$Fr t$_{1/2}$= 4.8 minute recoils. The implanted A=225 source would be shipped to TRIUMF, where it would be held for several minutes at a time a few mm from the same yttrium foil that normally receives the ISAC beam. SRIM calculations imply that 20% of the $^{221}$Fr will be implanted in a 1 cm diameter spot on the yttrium. Then the yttrium foil is moved to the trap and heated to release the Fr atoms, just as in normal ISAC online operation. A test implantation will be done at 10$^{7}$/sec production for 1 day, testing whether carbon cracking on the implantation foil in the mass separ...

  8. The polarized H and D atomic beam source for ANKE at COSY-Jülich

    Energy Technology Data Exchange (ETDEWEB)

    Mikirtychyants, M., E-mail: m.mikirtychyants@fz-juelich.de [Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich (Germany); High Energy Physics Department, St.Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation); Engels, R. [Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich (Germany); Grigoryev, K. [Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich (Germany); High Energy Physics Department, St.Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation); Kleines, H. [Zentrallabor für Elektronik, Forschungszentrum Jülich, 52425 Jülich (Germany); Kravtsov, P. [High Energy Physics Department, St.Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation); Lorenz, S. [Physikalisches Institut, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen (Germany); Nekipelov, M. [Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich (Germany); High Energy Physics Department, St.Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation); Nelyubin, V. [High Energy Physics Department, St.Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation); Rathmann, F.; Sarkadi, J. [Institut für Kernphysik, Forschungszentrum Jülich, 52425 Jülich (Germany); and others

    2013-09-01

    A polarized atomic beam source was developed for the polarized internal storage-cell gas target at the magnet spectrometer ANKE of COSY-Jülich. The intensities of the beams injected into the storage cell, measured with a compression tube, are 7.5×10{sup 16} hydrogen atoms/s (two hyperfine states) and 3.9×10{sup 16} deuterium atoms/s (three hyperfine states). For the hydrogen beam the achieved vector polarizations are p{sub z}≈±0.92. For the deuterium beam, the obtained combinations of vector and tensor (p{sub zz}) polarizations are p{sub z}≈±0.90 (with a constant p{sub zz}≈+0.86), and p{sub zz}=+0.90 or p{sub zz}=−1.71 (both with vanishing p{sub z}). The paper includes a detailed technical description of the apparatus and of the investigations performed during the development. This source has been very successfully used for single and double polarization measurements at ANKE as well as for studies of the polarization of recombining hydrogen molecules.

  9. Informal proposal for an Atomic Physics Facility at the National Synchrotron Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Jones, K.W.; Johnson, B.M.; Meron, M.

    1986-01-01

    An Atomic Physics Facility (APF) for experiments that will use radiation from a superconducting wiggler on the NSLS X-13 port is described. The scientific justification for the APF is given and the elements of the facility are discussed. It is shown that it will be possible to conduct a uniquely varied set of experiments that can probe most aspects of atomic physics. A major component of the proposal is a heavy-ion storage ring capable of containing ions with energies of about 10 MeV/nucleon. The ring can be filled with heavy ions produced at the BNL MP Tandem Laboratory or from independent ion-source systems. A preliminary cost estimate for the facility is presented.

  10. A surface-patterned chip as a strong source of ultra-cold atoms for quantum technologies

    CERN Document Server

    Nshii, C C; Cotter, J P; Griffin, P F; Hinds, E A; Ironside, C N; See, P; Sinclair, A G; Riis, E; Arnold, A S

    2013-01-01

    Laser cooled atoms are central to modern precision measurements. They are also increasingly important as an enabling technology for experimental cavity quantum electrodynamics, quantum information processing and matter wave interferometry. Although significant progress has been made in miniaturising atomic metrological devices, these are limited in accuracy by their use of hot atomic ensembles and buffer gases. Advances have also been made in producing portable apparatus that benefit from the advantages of atoms in the microKelvin regime. However, simplifying atomic cooling and loading using microfabrication technology has proved difficult. In this letter we address this problem, realising an atom chip that enables the integration of laser cooling and trapping into a compact apparatus. Our source delivers ten thousand times more atoms than previous magneto-optical traps with microfabricated optics and, for the first time, can reach sub-Doppler temperatures. Moreover, the same chip design offers a simple way t...

  11. Atomic Layer Deposition Al2O3 Thin Films in Magnetized Radio Frequency Plasma Source

    Science.gov (United States)

    Li, Xingcun; Chen, Qiang; Sang, Lijun; Yang, Lizhen; Liu, Zhongwei; Wang, Zhenduo

    Self-limiting deposition of aluminum oxide (Al2O3) thin films were accomplished by the plasma-enhanced chemical vapor deposition using trimethyl aluminum (TMA) and O2 as precursor and oxidant, respectively, where argon was kept flowing in whole deposition process as discharge and purge gas. In here we present a novel plasma source for the atomic layer deposition technology, magnetized radio frequency (RF) plasma. Difference from the commercial RF source, magnetic coils were amounted above the RF electrode, and the influence of the magnetic field strength on the deposition rate and morphology are investigated in detail. It concludes that a more than 3 Å/ purging cycle deposition rate and the good quality of ALD Al2O3 were achieved in this plasma source even without extra heating. The ultra-thin films were characterized by including Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectric spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The high deposition rates obtained at ambient temperatures were analyzed after in-situ the diagnostic of plasmas by Langmuir probe.

  12. Numerical analysis of atomic density distribution in arc driven negative ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T., E-mail: t.yamamoto@ppl.appi.keio.ac.jp; Shibata, T.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan); Kashiwagi, M.; Hanada, M. [Japan Atomic Energy Agency (JAEA), 801-1 Mukouyama, Naka 311-0193 (Japan); Sawada, K. [Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)

    2014-02-15

    The purpose of this study is to calculate atomic (H{sup 0}) density distribution in JAEA 10 ampere negative ion source. A collisional radiative model is developed for the calculation of the H{sup 0} density distribution. The non-equilibrium feature of the electron energy distribution function (EEDF), which mainly determines the H{sup 0} production rate, is included by substituting the EEDF calculated from 3D electron transport analysis. In this paper, the H{sup 0} production rate, the ionization rate, and the density distribution in the source chamber are calculated. In the region where high energy electrons exist, the H{sup 0} production and the ionization are enhanced. The calculated H{sup 0} density distribution without the effect of the H{sup 0} transport is relatively small in the upper region. In the next step, the effect should be taken into account to obtain more realistic H{sup 0} distribution.

  13. Continuous-wave, single-frequency 229 nm laser source for laser cooling of cadmium atoms

    CERN Document Server

    Kaneda, Yushi; Merzlyak, Yevgeny; Yamaguchi, Atsushi; Hayashida, Keitaro; Ohmae, Noriaki; Katori, Hidetoshi

    2016-01-01

    Continuous-wave output at 229 nm for the application of laser cooling of Cd atoms was generated by the 4th harmonic using two successive second harmonic generation stages. Employing a single-frequency optically pumped semiconductor laser as a fundamental source, 0.56 W of output at 229 nm was observed with a 10-mm long, Brewster-cut BBO crystal in an external cavity with 1.62 W of 458 nm input. Conversion efficiency from 458 nm to 229 nm was more than 34%. By applying a tapered amplifier as a fundamental source, we demonstrated magneto-optical trapping of all stable Cd isotopes including isotopes $^{111}$Cd and $^{113}$Cd, which are applicable to optical lattice clocks.

  14. Suppression of Emittance Growth Using a Shaped Cold Atom Electron and Ion Source

    Science.gov (United States)

    Thompson, D. J.; Murphy, D.; Speirs, R. W.; van Bijnen, R. M. W.; McCulloch, A. J.; Scholten, R. E.; Sparkes, B. M.

    2016-11-01

    We demonstrate precise control of charged particle bunch shape with a cold atom electron and ion source to create bunches with linear and, therefore, reversible Coulomb expansion. Using ultracold charged particles enables detailed observation of space-charge effects without loss of information from thermal diffusion, unambiguously demonstrating that shaping in three dimensions can result in a marked reduction of Coulomb-driven emittance growth. We show that the emittance growth suppression is accompanied by an increase in bunch focusability and brightness, improvements necessary for the development of sources capable of coherent single-shot ultrafast electron diffraction of noncrystalline objects, with applications ranging from femtosecond chemistry to materials science and rational drug design.

  15. Hydrogen atom temperature measured with wavelength-modulated laser absorption spectroscopy in large scale filament arc negative hydrogen ion source

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, H., E-mail: nakano@nifs.ac.jp; Goto, M.; Tsumori, K.; Kisaki, M.; Ikeda, K.; Nagaoka, K.; Osakabe, M.; Takeiri, Y.; Kaneko, O. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 5095292 (Japan); Nishiyama, S.; Sasaki, K. [Graduate school of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 0608628 (Japan)

    2015-04-08

    The velocity distribution function of hydrogen atoms is one of the useful parameters to understand particle dynamics from negative hydrogen production to extraction in a negative hydrogen ion source. Hydrogen atom temperature is one of the indicators of the velocity distribution function. To find a feasibility of hydrogen atom temperature measurement in large scale filament arc negative hydrogen ion source for fusion, a model calculation of wavelength-modulated laser absorption spectroscopy of the hydrogen Balmer alpha line was performed. By utilizing a wide range tunable diode laser, we successfully obtained the hydrogen atom temperature of ∼3000 K in the vicinity of the plasma grid electrode. The hydrogen atom temperature increases as well as the arc power, and becomes constant after decreasing with the filling of hydrogen gas pressure.

  16. A low phase noise microwave source for atomic spin squeezing experiments in 87Rb

    CERN Document Server

    Chen, Zilong; Weiner, Joshua M; Thompson, James K; 10.1063/1.3700247

    2012-01-01

    We describe and characterize a simple, low cost, low phase noise microwave source that operates near 6.800 GHz for agile, coherent manipulation of ensembles of 87Rb. Low phase noise is achieved by directly multiplying a low phase noise 100 MHz crystal to 6.8 GHz using a non-linear transmission line and filtering the output with custom band-pass filters. The fixed frequency signal is single sideband modulated with a direct digital synthesis frequency source to provide the desired phase, amplitude, and frequency control. Before modulation, the source has a single sideband phase noise near -140 dBc/Hz in the range of 10 kHz to 1 MHz offset from the carrier frequency and -130 dBc/Hz after modulation. The resulting source is estimated to contribute added spin-noise variance 16 dB below the quantum projection noise level during quantum nondemolition measurements of the clock transition in an ensemble 7x10^5 87Rb atoms.

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

    CERN Document Server

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

    2015-01-01

    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 uK 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. Never...

  18. Are the sungrazing comets the inner source of pickup ions and energetic neutral atoms?

    CERN Document Server

    Bzowski, M

    2004-01-01

    We show arguments that at least part of the inner source of pickup ions and energetic neutral atoms (~ 1 keV) might be the material released by sungrazing comets.Based on the monthly apparition statistics we postulate that the actual number of sungrazing comets may be even higher than observed. We point out that an overwhelming majority of the observed sungrazers belong to the Kreutz group of comets which follow tightly clumped orbits and break up at $\\sim 40 - 4$ solar radii in a well defined region. The material released from these comets should be (after ionization) at least an important portion of the inner source of pickup ions. We suggest that PUI from the cometary source should be accompanied by an increased level of ENA of similar energy. We indicate time intervals during the year when the cometary PUI should be observed from a spacecraft at Earth's orbit (basically, from the end of July till the end of the year) and show three time intervals, when they should be observable by Ulysses (since launch ti...

  19. Hydroxyl radical electrochemically generated with water as the complete atom source and its environmental application

    Institute of Scientific and Technical Information of China (English)

    CONG YanQing; WU ZuCheng; LI YuQiong

    2007-01-01

    The most reactive hydroxyl radical(·OH) was generated by electrochemical approach with safe water as the complete atom source. The direct evidence for ·OH formation was obtained by electron spin resonance method. The powerful ·OH electrochemically generated could effectively degrade organic pollutants and reduce the toxicity of wastewater. Electrochemical disinfection by ·OH was considerably efficient even without the aid of active chlorine. Bacteria inactivation of 99.99% was achieved for contact time of 30 min and current density of 5 mA.cm-2. In comparison with active chlorine, ·OH is rather attractive as a promising environmentally benign disinfectant and opens a new route for microbial inactivation.

  20. An open source/real-time atomic force microscope architecture to perform customizable force spectroscopy experiments.

    Science.gov (United States)

    Materassi, Donatello; Baschieri, Paolo; Tiribilli, Bruno; Zuccheri, Giampaolo; Samorì, Bruno

    2009-08-01

    We describe the realization of an atomic force microscope architecture designed to perform customizable experiments in a flexible and automatic way. Novel technological contributions are given by the software implementation platform (RTAI-LINUX), which is free and open source, and from a functional point of view, by the implementation of hard real-time control algorithms. Some other technical solutions such as a new way to estimate the optical lever constant are described as well. The adoption of this architecture provides many degrees of freedom in the device behavior and, furthermore, allows one to obtain a flexible experimental instrument at a relatively low cost. In particular, we show how such a system has been employed to obtain measures in sophisticated single-molecule force spectroscopy experiments [Fernandez and Li, Science 303, 1674 (2004)]. Experimental results on proteins already studied using the same methodologies are provided in order to show the reliability of the measure system.

  1. I.C.E.: An Ultra-Cold Atom Source for Long-Baseline Interferometric Inertial Sensors in Reduced Gravity

    CERN Document Server

    Varoquaux, Gaël; Chaibi, Walid; Clément, Jean-François; Carraz, Olivier; Brantut, Jean Philippe; Nyman, Robert A; Santos, Franck Pereira Dos; Mondin, Linda; Rouzé, Michel; Bidel, Yannick; Bresson, Alexandre; Landragin, Arnaud; Bouyer, Philippe

    2007-01-01

    The accuracy and precision of current atom-interferometric inertialsensors rival state-of-the-art conventional devices using artifact-based test masses . Atomic sensors are well suited for fundamental measurements of gravito-inertial fields. The sensitivity required to test gravitational theories can be achieved by extending the baseline of the interferometer. The I.C.E. (Interf\\'erom\\'etrie Coh\\'erente pour l'Espace) interferometer aims to achieve long interrogation times in compact apparatus via reduced gravity. We have tested a cold-atom source during airplane parabolic flights. We show that this environment is compatible with free-fall interferometric measurements using up to 4 second interrogation time. We present the next-generation apparatus using degenerate gases for low release-velocity atomic sources in space-borne experiments.

  2. Application of atomic and nuclear techniques to the study of inhomogeneities in electrodeposited {alpha}-particle sources

    Energy Technology Data Exchange (ETDEWEB)

    Martin Sanchez, A. E-mail: ams@unex.es; Nuevo, M.J.; Jurado Vargas, M.; Diaz Bejarano, J.; Silva, M.F. da; Roldan Garcia, C.; Paul, A.; Ferrero Calabuig, J.L.; Mendez Vilas, A.; Juanes Barber, D

    2002-05-01

    Three {alpha}-particle sources made by different methods of electrodeposition were analysed using {alpha}-particle spectrometry, Rutherford backscattering (RBS), and atomic force microscopy (AFM) on several surface zones. The thickness and homogeneity of these sources was studied using RBS, and the results were analysed jointly with those obtained with {alpha}-particle spectrometry and AFM techniques. The comparison of the electrodeposition methods showed that the most homogeneous electrodeposited zones corresponded to the source made with a stirring cathode.

  3. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Reininger, Charlotte; Woodfield, Kellie [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States); Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M. [Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA 30332 (United States); Farnsworth, Paul B., E-mail: paul_farnsworth@byu.edu [Brigham Young University, Department of Chemistry and Biochemistry, Provo, UT 84602 (United States)

    2014-10-01

    The absolute number densities of helium atoms in the 2s {sup 3}S{sub 1} metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 10{sup 12} cm{sup −3} and 0.011 × 10{sup 12} cm{sup −3}, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 10{sup 12} cm{sup −3} and 0.97 × 10{sup 12} cm{sup −3} were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges. - Highlights: • We determine He metastable number densities for four plasma types • The highest number densities were observed in a dielectric barrier discharge • No helium metastable atoms were observed downstream from the exits of glow discharges.

  4. Absolute number densities of helium metastable atoms determined by atomic absorption spectroscopy in helium plasma-based discharges used as ambient desorption/ionization sources for mass spectrometry

    Science.gov (United States)

    Reininger, Charlotte; Woodfield, Kellie; Keelor, Joel D.; Kaylor, Adam; Fernández, Facundo M.; Farnsworth, Paul B.

    2014-10-01

    The absolute number densities of helium atoms in the 2s 3S1 metastable state were determined in four plasma-based ambient desorption/ionization sources by atomic absorption spectroscopy. The plasmas included a high-frequency dielectric barrier discharge (HF-DBD), a low temperature plasma (LTP), and two atmospheric-pressure glow discharges, one with AC excitation and the other with DC excitation. Peak densities in the luminous plumes downstream from the discharge capillaries of the HF-DBD and the LTP were 1.39 × 1012 cm- 3 and 0.011 × 1012 cm- 3, respectively. Neither glow discharge produced a visible afterglow, and no metastable atoms were detected downstream from the capillary exits. However, densities of 0.58 × 1012 cm- 3 and 0.97 × 1012 cm- 3 were measured in the interelectrode regions of the AC and DC glow discharges, respectively. Time-resolved measurements of metastable atom densities revealed significant random variations in the timing of pulsed absorption signals with respect to the voltage waveforms applied to the discharges.

  5. Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function.

    Science.gov (United States)

    Koga, S; Shibata, T; Terasaki, R; Kameyama, N; Hatayama, A; Bacal, M; Tsumori, K

    2012-02-01

    In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H(-) production on the PG surface. We have developed a neutral (H(2) molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H(2) and H transport in a NIFS-R&D ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eV < E < 30 eV is important for the dissociation rate of H(2) molecules by the electron impact collision and the resultant H atom flux on the PG.

  6. Determination of effective atomic numbers, effective electrons numbers, total atomic cross-sections and buildup factor of some compounds for different radiation sources

    Science.gov (United States)

    Levet, A.; Özdemir, Y.

    2017-01-01

    The photon interaction parameters such as mass attenuation coefficient, effective atomic number, effective electron density, buildup factor have been measured for Fe(NO3)3, V4O2, NaCO3·H2O, C6H5FeO7·H2O and CuCI compounds using 137Ba, 157Gd and 241Am γ-rays sources in stable geometry. The mass attenuation coefficients have been determined experimentally via Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) system and theoretically by using WinXCom computer program. Then, effective atomic numbers, Zeff, and electron densities, Neff, have been calculated by using the mass attenuation coefficients. The obtained values of effective atomic numbers have been compared with the ones calculated according to a different approach proposed by Hine and the calculated ones from theory. Also, photon buildup factors were obtained by changing collimator diameters in the different photon energies. We observed that the buildup factor increased as the collimator diameter increased for all sources used.

  7. Collisional Decoherence in Trapped-Atom Interferometers that use Nondegenerate Sources

    Science.gov (United States)

    2009-01-22

    atomic cloud experiences a nonuniform potential during the interferometer cycle, the density echoes will be shifted relative to the initial modula- tion...verify the analytic model. 15. SUBJECT TERMS Topside ionosphere Electron density Ionospheric model Altitude profile 16. SECURITY CLASSIFICATION OF: a...sensitive free space atom in- terferometers, the atomic clouds travel up to 10 meters [21. The large scale of free space interferometers limits their

  8. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    DEFF Research Database (Denmark)

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.;

    2012-01-01

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...... is capable of loading 90 of a magneto-optical trap (MOT) in less than 7 s while maintaining a low vacuum pressure of 10 -11 Torr. The transverse velocity components of the atomic beam are measured to be within typical capture velocities of a rubidium MOT. Finally, we show that the atomic beam can be turned...

  9. Atomic physics with hard X-rays from high brilliance synchrotron light sources

    Energy Technology Data Exchange (ETDEWEB)

    Southworth, S.; Gemmell, D.

    1996-08-01

    A century after the discovery of x rays, the experimental capability for studying atomic structure and dynamics with hard, bright synchrotron radiation is increasing remarkably. Tempting opportunities arise for experiments on many-body effects, aspects of fundamental photon-atom interaction processes, and relativistic and quantum-electrodynamic phenomena. Some of these possibilities are surveyed in general terms.

  10. Production of rare-earth atomic negative ion beams in a cesium-sputter-type negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Davis, V.T. [Test Support Division, Defense Threat Reduction Agency, West Desert Test Center, Dugway, UT 84022-5000 (United States)]. E-mail: vernon.davis@us.army.mil; Covington, A.M. [Department of Physics, University of Nevada, MS 220, Reno, NV 89557-0058 (United States); Duvvuri, S.S. [Department of Physics, University of Nevada, MS 220, Reno, NV 89557-0058 (United States); Kraus, R.G. [Department of Physics, University of Nevada, MS 220, Reno, NV 89557-0058 (United States); Emmons, E.D. [Department of Physics, University of Nevada, MS 220, Reno, NV 89557-0058 (United States); Kvale, T.J. [Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Thompson, J.S. [Department of Physics, University of Nevada, MS 220, Reno, NV 89557-0058 (United States)

    2007-08-15

    The desire to study negative ion structure and negative ion-photon interactions has spurred the development of ion sources for use in research and industry. The many different types of negative ion sources available today differ in their characteristics and abilities to produce anions of various species. Thus the importance of choosing the correct type of negative ion source for a particular research or industrial application is clear. In this study, the results of an investigation on the production of beams composed of negatively-charged rare-earth ions from a cylindrical-cathode-geometry, cesium-sputter-type negative ion source are presented. Beams of atomic anions have been observed for most of the first-row rare-earth elements, with typical currents ranging from hundreds of picoamps to several nanoamps.

  11. Source of slow lithium atoms from Ne or H2 matrix isolation sublimation.

    Science.gov (United States)

    Sacramento, R L; Alves, B X; Almeida, D T; Wolff, W; Li, M S; Cesar, C L

    2012-04-21

    We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from cryogenic matrices of solid neon or molecular hydrogen. The Li atoms are implanted into the Ne or H(2) matrices--grown onto a sapphire substrate--by laser ablation of a solid Li or LiH precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms. With a NiCr film resistor deposited directly onto the sapphire substrate we are able to transfer high instantaneous power to the matrix, thus reaching a fast sublimation regime. In this regime the Li atoms can get entrained in the released matrix gas, and we were also able to achieve matrix sublimation times down to 10 μs for both H(2) or Ne matrix, enabling us to proceed with the trapping of the species of our interest such as atomic hydrogen, lithium, and molecules. The sublimation of the H(2) matrix, with its large center-of-mass velocity, provides evidence for a new regime of one-dimensional thermalization. The laser ablated Li seems to penetrate the H(2) matrix deeper than it does in Ne.

  12. Investigation of an alternating current plasma as an element selective atomic emission detector for high-resolution capillary gas chromatography and as a source for atomic absorption and atomic emission spectrometry

    Science.gov (United States)

    Ombaba, Jackson M.

    This thesis deals with the construction and evaluation of an alternating current plasma (ACP) as an element-selective detector for high resolution capillary gas chromatography (GC) and as an excitation source for atomic absorption spectrometry (AAS) and atomic emission spectrometry (AES). The plasma, constrained in a quartz discharge tube at atmospheric pressure, is generated between two copper electrodes and utilizes helium as the plasma supporting gas. The alternating current plasma power source consists of a step-up transformer with a secondary output voltage of 14,000 V at a current of 23 mA. The device exhibits a stable signal because the plasma is self-seeding and reignites itself every half cycle. A tesla coil is not required to commence generation of the plasma if the ac voltage applied is greater than the breakdown voltage of the plasma-supporting gas. The chromatographic applications studied included the following: (1) the separation and selective detection of the organotin species, tributyltin chloride (TBT) and tetrabutyltin (TEBT), in environmental matrices including mussels (Mvutilus edullus) and sediment from Boston Harbor, industrial waste water and industrial sludge, and (2) the detection of methylcyclopentadienyl manganesetricarbonyl (MMT) and similar compounds used as gasoline additives. An ultrasonic nebulizer (common room humidifier) was utilized as a sample introduction device for aqueous solutions when the ACP was employed as an atomization source for atomic absorption spectrometry and as an excitation source for atomic emission spectrometry. Plasma diagnostic parameters studied include spatial electron number density across the discharge tube, electronic, excitation and ionization temperatures. Interference studies both in absorption and emission modes were also considered. Figures of merits of selected elements both in absorption and emission modes are reported. The evaluation of a computer-aided optimization program, Drylab GC, using

  13. Physics of non-steady state diffusion of lightweight atoms in a heavy atom matrix. Introducing an open-source tool for simulated-experiments in fluid mechanics

    CERN Document Server

    Serrano-López, Roberto; Tapia-Júdez, Oscar; Fradera, Jorge

    2013-01-01

    The practice-based learning methodologies offer to undergraduate professors different ways to illustrate certain general physic principles. Traditional experimental workbenches have been extensively used during decades for academic lessons in order to complete theoretical dissertations or lectures, aiming at assuring an adequate understanding. The high cost of materials and laboratory equipment, the excessive preparation time, and the difficulty for carrying out offsite-campus replications by students, are disadvantages that can discourage of trying new kinds of experimental tasks. This paper gives insight of simulated experiment possibilities through an open-source-based computational suite in teaching fluid mechanics. Physics underlying diffusion of a light specie in a heavier atom matrix, as function of time and position, were explained to students as an example to teach them the Fick's Second Law expression. We present a docent step-by-step programme, scheduled in three sessions. The expected solution is ...

  14. High-resolution continuum source electrothermal atomic absorption spectrometry: Linearization of the calibration curves within a broad concentration range

    Energy Technology Data Exchange (ETDEWEB)

    Katskov, Dmitri, E-mail: katskovda@tut.ac.za [Tshwane University of Technology, Chemistry Department, Pretoria 0001 (South Africa); Hlongwane, Miranda [Tshwane University of Technology, Chemistry Department, Pretoria 0001 (South Africa); Heitmann, Uwe [German Aerospace Center, Rose-Luxemburg Str. 2, 10178 Berlin (Germany); Florek, Stefan [ISAS-Leibniz-Institut fuer Analytische Wissenschaften e.V., Albert-Einstein-Str. 9,12489 Berlin (Germany)

    2012-05-15

    The calculation algorithm suggested provides linearization of the calibration curves in high-resolution continuum source electrothermal atomic absorption spectrometry. The algorithm is based on the modification of the function wavelength-integrated absorbance vs. concentration of analyte vapor in the absorption volume. According to the suggested approach, the absorption line is represented by a triangle for low and trapezium for high analyte vapor concentration in the absorption volume. The respective semi-empirical formulas include two linearization parameters, which depend on properties of the absorption line and characteristics of the atomizer and spectrometer. The parameters can be approximately evaluated from the theory and determined in practice from the original broad-range calibration curve. The parameters were found and the proposed calculation algorithm verified in the experiments on direct determination of Ag, Cd, Cu, Fe, Mn and Pb in the solutions within a concentration ranges from 0.15 to 625 {mu}g{center_dot}L{sup -1} using tube, platform tube and filter furnace atomizers. The use of various atomizers, lines, elements and atomization temperatures made possible the simulation of various practical analytical conditions. It was found that the algorithm and optimal linearization parameters made it possible to obtain for each line and atomizer linear approximations of the calibration curves within 3-4 orders of magnitude with correlation coefficients close to 0.999. The algorithm makes possible to employ a single line for the direct element determination over a broad concentration range. The sources of errors and the possibility of a priori theoretical evaluation of the linearization parameters are discussed. - Highlights: Black-Right-Pointing-Pointer New calculation algorithm for HR-CS ET AAS measurements was proposed and applied. Black-Right-Pointing-Pointer The suggested formulas include two parameters to be determined experimentally. Black

  15. Interfacing transitions of different alkali atoms and telecom bands using one narrowband photon pair source

    DEFF Research Database (Denmark)

    Schunk, Gerhard; Vogl, Ulrich; Strekalov, Dmitry V.;

    2015-01-01

    Quantum information technology strongly relies on the coupling of optical photons with narrowband quantum systems, such as quantum dots, color centers, and atomic systems. This coupling requires matching the optical wavelength and bandwidth to the desired system, which presents a considerable pro...

  16. Femtosecond electron diffraction. Next generation electron sources for atomically resolved dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Hirscht, Julian

    2015-08-15

    Three instruments for femtosecond electron diffraction (FED) experiments were erected, partially commissioned and used for first diffraction experiments. The Relativistic Electron Gun for Atomic Exploration (REGAE) was completed by beamline elements including supports, a specimen chamber and dark current or electron beam collimating elements such that the commissioning process, including first diffraction experiments in this context, could be started. The temporal resolution of this machine is simulated to be 25 fs (fwhm) short, while a transverse coherence length of 30 nm (fwhm) is feasible to resolve proteins on this scale. Whether this machine is capable of meeting these predictions or whether the dynamics of the electron beam will stay limited by accelerator components, is not finally determined by the end of this work, because commissioning and improvement of accelerator components is ongoing. Simultaneously, a compact DC electron diffraction apparatus, the E-Gun 300, designed for solid and liquid specimens and a target electron energy of 300 keV, was built. Fundamental design issues of the high potential carrying and beam generating components occurred and are limiting the maximum potential and electron energy to 120 keV. Furthermore, this is limiting the range of possible applications and consequently the design and construction of a brand new instrument began. The Femtosecond Electron Diffraction CAmera for Molecular Movies (FED-CAMM) bridges the performance problems of very high electric potentials and provides optimal operational conditions for all applied electron energies up to 300 keV. The variability of gap spacings and optimized manufacturing of the high voltage electrodes lead to the best possible electron pulse durations obtainable with a compact DC setup, that does not comprise of rf-structures. This third apparatus possesses pulse durations just a few tenth femtoseconds apart from the design limit of the highly relativistic REGAE and combines the

  17. Analysis of H atoms in a negative ion source plasma with the non-equilibrium electron energy distribution function

    Energy Technology Data Exchange (ETDEWEB)

    Koga, S.; Shibata, T.; Terasaki, R.; Kameyama, N.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Bacal, M. [LPP, Ecole Polytechnique, Palaiseau, UPMC, Universite PARIS-SUD 11, UMR CNRS 7648 (France); Tsumori, K. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

    2012-02-15

    In negative ion sources for the neutral beam injection, it is important to calculate H atom flux onto the plasma grid (PG) surface for the evaluation of H{sup -} production on the PG surface. We have developed a neutral (H{sub 2} molecules and H atoms) transport code. In the present study, the neutral transport code is applied to the analysis of the H{sub 2} and H transport in a NIFS-R and D ion source in order to calculate the flux onto the PG surface. Taking into account non-equilibrium feature of the electron energy distribution function (EEDF), i.e., the fast electron component, we have done the neutral transport simulation. The results suggest that the precise evaluation of the EEDF, especially in the energy range 15 eV < E < 30 eV is important for the dissociation rate of H{sub 2} molecules by the electron impact collision and the resultant H atom flux on the PG.

  18. Thermodynamics of various F420 coenzyme models as sources of electrons, hydride ions, hydrogen atoms and protons in acetonitrile.

    Science.gov (United States)

    Xia, Ke; Shen, Guang-Bin; Zhu, Xiao-Qing

    2015-06-14

    32 F420 coenzyme models with alkylation of the three different N atoms (N1, N3 and N10) in the core structure (XFH(-)) were designed and synthesized and the thermodynamic driving forces (defined in terms of the molar enthalpy changes or the standard redox potentials in this work) of the 32 XFH(-) releasing hydride ions, hydrogen atoms and electrons, the thermodynamic driving forces of the 32 XFH˙ releasing protons and hydrogen atoms and the thermodynamic driving forces of XF(-)˙ releasing electrons in acetonitrile were determined using titration calorimetry and electrochemical methods. The effects of the methyl group at N1, N3 and N10 and a negative charge on N1 and N10 atoms on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were examined; the results show that seating arrangements of the methyl group and the negative charge have remarkably different effects on the thermodynamic properties of the F420 coenzyme models and their related reaction intermediates. The effects of the substituents at C7 and C8 on the six thermodynamic driving forces of the F420 coenzyme models and their related reaction intermediates were also examined; the results show that the substituents at C7 and C8 have good Hammett linear free energy relationships with the six thermodynamic parameters. Meanwhile, a reasonable determination of possible reactions between members of the F420 family and NADH family in vivo was given according to a thermodynamic analysis platform constructed using the elementary step thermodynamic parameter of F420 coenzyme model 2FH(-) and NADH model MNAH releasing hydride ions in acetonitrile. The information disclosed in this work can not only fill a gap in the chemical thermodynamics of F420 coenzyme models as a class of very important organic sources of electrons, hydride ions, hydrogen atoms and protons, but also strongly promote the fast development of the chemistry and applications of F420 coenzyme.

  19. Get Your Atoms in Order--An Open-Source Implementation of a Novel and Robust Molecular Canonicalization Algorithm.

    Science.gov (United States)

    Schneider, Nadine; Sayle, Roger A; Landrum, Gregory A

    2015-10-26

    Finding a canonical ordering of the atoms in a molecule is a prerequisite for generating a unique representation of the molecule. The canonicalization of a molecule is usually accomplished by applying some sort of graph relaxation algorithm, the most common of which is the Morgan algorithm. There are known issues with that algorithm that lead to noncanonical atom orderings as well as problems when it is applied to large molecules like proteins. Furthermore, each cheminformatics toolkit or software provides its own version of a canonical ordering, most based on unpublished algorithms, which also complicates the generation of a universal unique identifier for molecules. We present an alternative canonicalization approach that uses a standard stable-sorting algorithm instead of a Morgan-like index. Two new invariants that allow canonical ordering of molecules with dependent chirality as well as those with highly symmetrical cyclic graphs have been developed. The new approach proved to be robust and fast when tested on the 1.45 million compounds of the ChEMBL 20 data set in different scenarios like random renumbering of input atoms or SMILES round tripping. Our new algorithm is able to generate a canonical order of the atoms of protein molecules within a few milliseconds. The novel algorithm is implemented in the open-source cheminformatics toolkit RDKit. With this paper, we provide a reference Python implementation of the algorithm that could easily be integrated in any cheminformatics toolkit. This provides a first step toward a common standard for canonical atom ordering to generate a universal unique identifier for molecules other than InChI.

  20. An open source digital servo for atomic, molecular, and optical physics experiments.

    Science.gov (United States)

    Leibrandt, D R; Heidecker, J

    2015-12-01

    We describe a general purpose digital servo optimized for feedback control of lasers in atomic, molecular, and optical physics experiments. The servo is capable of feedback bandwidths up to roughly 1 MHz (limited by the 320 ns total latency); loop filter shapes up to fifth order; multiple-input, multiple-output control; and automatic lock acquisition. The configuration of the servo is controlled via a graphical user interface, which also provides a rudimentary software oscilloscope and tools for measurement of system transfer functions. We illustrate the functionality of the digital servo by describing its use in two example scenarios: frequency control of the laser used to probe the narrow clock transition of (27)Al(+) in an optical atomic clock, and length control of a cavity used for resonant frequency doubling of a laser.

  1. Femtosecond Electron Diffraction: Next generation electron sources for atomically resolved dynamics

    OpenAIRE

    Hirscht, Julian

    2015-01-01

    Three instruments for femtosecond electron diffraction (FED) experiments were erected, partially commissioned and used for first diffraction experiments. The Relativistic Electron Gun for Atomic Exploration (REGAE) was completed by beamline elements including supports, a specimen chamber and dark current or electron beam collimating elements such that the commissioning process, including first diffraction experiments in this context, could be started. The temporal resolution of this machine i...

  2. Hypervelocity Oxygen Source for the Study of Atom-Surface Interactions.

    Science.gov (United States)

    1987-04-01

    conclusions. Based on two space shuttle flights (STS-5 and STS-8), they have established that carbon based composites, polymers and organic films have...under single collision conditions. The most popular technique for studying "hot atom chemistry" today involves photodissociating precursor molecules to...ultraviolet solar flux. Recent results indicate for instance, that silicon dioxide , normally quite inert to further reaction, can be made unstable by 4 4-5

  3. Spectral aspects of the determination of Si in organic and aqueous solutions using high-resolution continuum source or line source flame atomic absorption spectrometry

    Science.gov (United States)

    Kowalewska, Zofia; Pilarczyk, Janusz; Gościniak, Łukasz

    2016-06-01

    High-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was applied to reveal and investigate spectral interference in the determination of Si. An intensive structured background was observed in the analysis of both aqueous and xylene solutions containing S compounds. This background was attributed to absorption by the CS molecule formed in the N2O-C2H2 flame. The lines of the CS spectrum at least partially overlap all five of the most sensitive Si lines investigated. The 251.611 nm Si line was demonstrated to be the most advantageous. The intensity of the structured background caused by the CS molecule significantly depends on the chemical form of S in the solution and is the highest for the most-volatile CS2. The presence of O atoms in an initial S molecule can diminish the formation of CS. To overcome this S effect, various modes of baseline fitting and background correction were evaluated, including iterative background correction (IBC) and utilization of correction pixels (WRC). These modes were used either independently or in conjunction with least squares background correction (LSBC). The IBC + LSBC mode can correct the extremely strong interference caused by CS2 at an S concentration of 5% w:w in the investigated solution. However, the efficiency of this mode depends on the similarity of the processed spectra and the correction spectra in terms of intensity and in additional effects, such as a sloping baseline. In the vicinity of the Si line, three lines of V were recorded. These lines are well-separated in the HR-CS FAAS spectrum, but they could be a potential source of overcorrection when using line source flame atomic absorption spectrometry (LS FAAS). The expected signal for the 251.625 nm Fe line was not registered at 200 mg L- 1 Fe concentration in the solution, probably due to the diminished population of Fe atoms in the high-temperature flame used. The observations made using HR-CS FAAS helped to establish a "safe" level

  4. Analyzing Capabilities of Commercial and Open-Source Routers to Implement Atomic BGP

    Directory of Open Access Journals (Sweden)

    A. Cvjetić

    2010-06-01

    Full Text Available The paper analyzes implementations of BGP protocol on commercial and open-source routers and presents how some existing BGP extensions and routing table isolation mechanisms may be used to solve issues found in standard BGP implementation.

  5. Atomic processes and equation of state of high Z plasmas for EUV sources and their effects on the spatial and temporal evolution of the plasmas

    Science.gov (United States)

    Sasaki, Akira; Sunahara, Atushi; Furukawa, Hiroyuki; Nishihara, Katsunobu; Nishikawa, Takeshi; Koike, Fumihiro

    2016-03-01

    Laser-produced plasma (LPP) extreme ultraviolet (EUV) light sources have been intensively investigated due to potential application to next-generation semiconductor technology. Current studies focus on the atomic processes and hydrodynamics of plasmas to develop shorter wavelength sources at λ = 6.x nm as well as to improve the conversion efficiency (CE) of λ = 13.5 nm sources. This paper examines the atomic processes of mid-z elements, which are potential candidates for λ = 6.x nm source using n=3-3 transitions. Furthermore, a method to calculate the hydrodynamics of the plasmas in terms of the initial interaction between a relatively weak prepulse laser is presented.

  6. Continuous-wave, single-frequency 229  nm laser source for laser cooling of cadmium atoms.

    Science.gov (United States)

    Kaneda, Yushi; Yarborough, J M; Merzlyak, Yevgeny; Yamaguchi, Atsushi; Hayashida, Keitaro; Ohmae, Noriaki; Katori, Hidetoshi

    2016-02-15

    Continuous-wave output at 229 nm for the application of laser cooling of Cd atoms was generated by the fourth harmonic using two successive second-harmonic generation stages. Employing a single-frequency optically pumped semiconductor laser as a fundamental source, 0.56 W of output at 229 nm was observed with a 10-mm long, Brewster-cut BBO crystal in an external cavity with 1.62 W of 458 nm input. Conversion efficiency from 458 nm to 229 nm was more than 34%. By applying a tapered amplifier (TA) as a fundamental source, we demonstrated magneto-optical trapping of all stable Cd isotopes including isotopes Cd111 and Cd113, which are applicable to optical lattice clocks.

  7. Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Yueh [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Wei-Tse; Chen, Yi-Sheng; Hwu, En-Te; Chang, Chia-Seng; Hwang, Ing-Shouh, E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Hsu, Wei-Hao [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2016-03-15

    In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.

  8. The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules

    CERN Document Server

    Hutzler, Nicholas R; Doyle, John M

    2011-01-01

    Beams of atoms and molecules are stalwart tools for spectroscopy and studies of collisional processes. The supersonic expansion technique can create cold beams of many species of atoms and molecules. However, the resulting beam is typically moving at a speed of 300-600 m/s in the lab frame, and for a large class of species has insufficient flux (i.e. brightness) for important applications. In contrast, buffer gas beams can be a superior method in many cases, producing cold and relatively slow molecules in the lab frame with high brightness and great versatility. There are basic differences between supersonic and buffer gas cooled beams regarding particular technological advantages and constraints. At present, it is clear that not all of the possible variations on the buffer gas method have been studied. In this review, we will present a survey of the current state of the art in buffer gas beams, and explore some of the possible future directions that these new methods might take.

  9. Determination of silicon and aluminum in silicon carbide nanocrystals by high-resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Dravecz, Gabriella; Bencs, László; Beke, Dávid; Gali, Adam

    2016-01-15

    The determination of Al contaminant and the main component Si in silicon carbide (SiC) nanocrystals with the size-distribution of 1-8nm dispersed in an aqueous solution was developed using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS). The vaporization/atomization processes were investigated in a transversally heated graphite atomizer by evaporating solution samples of Al and Si preserved in various media (HCl, HNO3). For Si, the best results were obtained by applying a mixture of 5µg Pd plus 5µg Mg, whereas for Al, 10µg Mg (each as nitrate solution) was dispensed with the samples, but the results obtained without modifier were found to be better. This way a maximum pyrolysis temperature of 1200°C for Si and 1300°C for Al could be used, and the optimum (compromise) atomization temperature was 2400°C for both analytes. The Si and Al contents of different sized SiC nanocrystals, dispersed in aqueous solutions, were determined against aqueous (external) calibration standards. The correlation coefficients (R values) of the calibrations were found to be 0.9963 for Si and 0.9991 for Al. The upper limit of the linear calibration range was 2mg/l Si and 0.25mg/l Al. The limit of detection was 3µg/l for Si and 0.5µg/l for Al. The characteristic mass (m0) was calculated to be 389pg Si and 6.4pg Al. The Si and Al content in the solution samples were found to be in the range of 1.0-1.7mg/l and 0.1-0.25mg/l, respectively.

  10. Resolved atomic lines reveal outflows in two ultraluminous X-ray sources

    CERN Document Server

    Pinto, Ciro; Fabian, Andrew C

    2016-01-01

    Ultraluminous X-ray sources are extragalactic, off-nucleus, point sources in galaxies with an X-ray luminosity above 3x10^39 erg/s, thought to be powered by accretion onto a compact object. Possible explanations include accretion onto neutron stars with strong magnetic fields, stellar-mass black holes ( 5 sigma, and blueshifted (~0.2c) absorption lines (5 sigma) in the high-resolution X-ray spectrum of the ultraluminous X-ray source NGC 1313 X-1. In a similar source, NGC 5408 X-1, we also detect emission lines at rest and blueshifted absorption. The blueshifted absorption lines must occur in a fast outflowing gas, whereas the emission lines originate in slow-moving gas around the source. We conclude that the compact object is surrounded by powerful winds with an outflow velocity of about 0.2c as predicted by models of accreting supermassive black holes and hyper-accreting stellar mass black holes.

  11. On the possibility of observable signatures of leptonic onium atoms from astrophysical sources

    CERN Document Server

    Ellis, S C

    2015-01-01

    The formation of Ps in our Galaxy is well measured, and has led to important and unanswered questions on the origin of the positrons. In principle it should be possible to form analogous systems from mu and tau leptons, viz. true muonium and true tauonium. However the probability of formation for these systems is greatly reduced due to the intrinsically short lifetimes of the mu and tau leptons. Likewise, the decay of the atoms is hastened by the high probability of the constituent particles decaying. Nevertheless, if significant numbers of mu and tau pairs are produced in high energy astrophysical environments there may be significant production of true muonium and true tauonium, despite the small probabilities. This paper addresses this possibility. We have calculated the pair production spectra of mu and tau leptons from photon-photon annihilation and electron-positron annihilation in astrophysical environments. We have computed the cross-sections for radiative recombination and direct annihilation of the ...

  12. New oxygen radical source using selective sputtering of oxygen atoms for high rate deposition of TiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, Yoji; Lei, Hao; Hoshi, Yoichi [Department of Electronics and Information Technology, Tokyo Polytechnic University, Kanagawa 243-0297 (Japan); State Key Laboratory for Corrosion and Protection, Surface Engineering of Materials Division, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Department of Electronics and Information Technology, Tokyo Polytechnic University, Kanagawa 243-0297 (Japan)

    2012-11-15

    We have developed a new oxygen radical source based on the reactive sputtering phenomena of a titanium target for high rate deposition of TiO{sub 2} films. In this oxygen radical source, oxygen radicals are mainly produced by two mechanisms: selective sputter-emission of oxygen atoms from the target surface covered with a titanium oxide layer, and production of high-density oxygen plasma in the space near the magnetron-sputtering cathode. Compared with molecular oxygen ions, the amount of atomic oxygen radicals increased significantly with an increase in discharge current so that atomic oxygen radicals were mainly produced by this radical source. It should be noted that oxygen atoms were selectively sputtered from the target surface, and titanium atoms sputter-emitted from the target cathode were negligibly small. The amount of oxygen radicals supplied from this radical source increased linearly with increasing discharge current, and oxygen radicals of 1 Multiplication-Sign 10{sup 15} atoms/s/cm{sup 2} were supplied to the substrate surface at a discharge current of 1.2 A. We conclude that our newly developed oxygen radical source can be a good tool to achieve high rate deposition and to control the structure of TiO{sub 2} films for many industrial design applications.

  13. The Decline of the Atom and the Rise of the Sun as Future Energy Sources

    Science.gov (United States)

    Bockris, J. O'M.

    1973-01-01

    Examines the various energy sources likely to be developed in the near future, and suggests that the only satisfactory solution lies in the development of solar energy and an associated non-polluting "hydrogen economy." Concludes that Australia has ideal conditions and the technical expertise to lead in solar energy research. (JR)

  14. In-source laser spectroscopy of polonium isotopes: From atomic physics to nuclear structure

    CERN Multimedia

    Rothe, S

    2014-01-01

    The Resonance Ionization Laser Ion Source RILIS [1] at the CERN-ISOLDE on-line radioactive ion beam facility is essential for ion beam production for the majority of experiments, but it is also powerful tool for laser spectroscopy of rare isotopes. A series of experiments on in-source laser spectroscopy of polonium isotopes [2, 3] revealed the nuclear ground state properties of 191;211;216;218Po. However, limitations caused by the isobaric background of surface-ionized francium isotopes hindered the study of several neutron rich polonium isotopes. The development of the Laser Ion Source and Trap (LIST) [4] and finally its integration at ISOLDE has led to a dramatic suppression of surface ions. Meanwhile, the RILIS laser spectroscopy capabilities have advanced tremendously. Widely tunable titanium:sapphire (Ti:Sa) lasers were installed to complement the established dye laser system. Along with a new data acquisition system [5], this more versatile laser setup enabled rst ever laser spectroscopy of the radioact...

  15. [Determination of trace elements in new food sources by flame atomic absorption spectrophotometry].

    Science.gov (United States)

    Liu, Li E; Ding, Li; Qi, Min; Han, Xiu Li; Zhang, Hong-Quan

    2007-07-01

    Samples were digested by HNO3 + HClO4. Flame atomic absorption spectrophotometry (FAAS) was successfully used to determine copper, zinc and iron in new resource food. Under our experimental conditions, the recovery ratio was 94.66%-108.80%; the precision was 0.71%-4.78%. This method of measuring elements is convenient, rapid and accurate. The results showed that there are profitable elements, such as copper, zinc and iron in new resourse food in Henan province. By F test and SNK test, the content sequence of metal elements was found as follows: copper, Chrysanthemum morifolium Ramat = Silkworm pupa > flowers of Pueraria lobata Ohwin = Wheat germ = Codonopsis lanceolata = roots of Pueraria lobata Ohwi > Opuntia dillenii Haw. Zinc, Opuntia dillenii Haw > Silkworm pupa = flowers of Pueraria lobata Ohwi = roots of Pueraria lobata Ohwi = Wheat germ = Codonopsis lanceolata = Chrysanthemum morifolium Ramat. Iron, Silkworm pupa = C hrysanthemum morifolium Ramat = roots of Pueraria lobata Ohwi > flowers of Pueraria lobata Ohwi = Wheat germ = Codonopis lanceolata = Opuntia dillenii Haw.

  16. Supersonic Fe beam source for chromatic aberration-free laser focusing of atoms

    CERN Document Server

    Bosch, R C M; Van der Straten, P; Leeuwen, K A H

    2002-01-01

    A monochromatic Fe beam is generated by heated supersonic expansion of argon seeded with Fe vapor. At a nozzle temperature of 1930 K and 800 torr argon inlet pressure the Fe beam has an axial velocity spread of 8% and intensity of 3 x 10 sup 1 sup 5 s sup - sup 1 sr sup - sup 1 , corresponding to a deposition rate of 10 nm/h at 150 mm from the nozzle. The two-chamber alumina crucibles are chemically stable for liquid Fe. With 400 mm sup 3 Fe we have operated for more than 200 hours without reloading. The power consumption at 1930 K is 750 W. Temperature stability at constant power (without feedback) is better than 30 K. The source is intended for deposition of nano-structures by laser focusing of the Fe beam. The small axial velocity spread virtually eliminates the increase in focal spot size due to chromatic aberration. (authors)

  17. Aspects of the competition between atom-field and field-environment couplings under the influence of an external source in dispersive Jaynes-Cummings model

    CERN Document Server

    De Faria, J G P

    2002-01-01

    We give a fully description of the dynamics of an atom dispersively coupled to a field mode in a dissipative environment fed by an external source. The competition between the unitary atom-field (which leads to entanglement) and the dissipative field-environment couplings are investigated in detail. We find the time evolution of the global atom-field system for any initial state and we show that atom-field steady state is at most classically correlated. For an initial state chosen, we evaluate the purity loss of the global system and of atomic and field subsystems as a function of time. We find that the source will tend to compensate for the dissipation of the field intensity and to accelerate decoherence of the global and atomic states. Moreover, we show that the degree of entanglement of the atom-field state, for the particular initial state chosen, can be completely quantified by concurrence. Analytical expression for time evolution of the concurrence is given.

  18. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  19. Suppression of single cesium atom heating in a microscopic optical dipole trap for demonstration of an 852nm triggered single-photon source

    CERN Document Server

    Liu, Bei; He, Jun; Wang, Junmin

    2016-01-01

    We investigate single cesium (Cs) atom heating owing to the momentum accumulation process induced by the resonant pulsed excitation in a microscopic optical dipole trap formed by a strongly focused 1064 nm laser beam. The heating depends on the trap frequency which restricts the maximum repetition rate of pulsed excitation. We experimentally verify the heating of a single atom and then demonstrate how to suppress it with an optimized pulsed excitation/cooling method. The typical trap lifetime of single Cs atom is extended from 108 +/- 6 us to 2536 +/- 31 ms, and the corresponding number of excitation increases from ~ 108 to ~ 360000. In applying this faster cooling method, we use the trapped single Cs atom as a triggered single-photon source at an excitation repetition rate of 10 MHz. The second-order intensity correlations of the emitted single photons are characterized by implementing Hanbury Brown and Twiss setup, and clear anti-bunching effect has been observed.

  20. Unusual calibration curves observed for iron using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Welz, Bernhard, E-mail: w.bernardo@terra.com.b [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Instituto Nacional de Ciencia e Tecnologia do CMPq-INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador-BA (Brazil); Santos, Lisia M.G. dos [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Instituto Nacional de Controle de Qualidade em Saude-INCQS-Fiocruz, 21040-900 Rio de Janeiro-RJ (Brazil); Araujo, Rennan G.O. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900 Florianopolis-SC (Brazil); Departamento de Quimica, Universidade Federal de Sergipe, 49100-000 Sao Cristovao-SE (Brazil); Jacob, Silvana do C. [Instituto Nacional de Controle de Qualidade em Saude-INCQS-Fiocruz, 21040-900 Rio de Janeiro-RJ (Brazil); Vale, Maria Goreti R. [Instituto Nacional de Ciencia e Tecnologia do CMPq-INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador-BA (Brazil); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre-RS (Brazil); Okruss, Michael; Becker-Ross, Helmut [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-Department Berlin, 12489 Berlin (Germany)

    2010-03-15

    The simultaneous determination of cadmium and iron in plant and soil samples has been investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry. The primary cadmium resonance line at 228.802 nm and an adjacent secondary iron line at 228.726 nm, which is within the spectral interval covered by the charge-coupled device (CCD) array detector, have been used for the investigations. Due to the very high iron content in most of the soil samples the possibility has been investigated to reduce the sensitivity and extend the working range by using side pixels for measurement at the line wings instead of the line core. It has been found that the calibration curves measured at all the analytically useful pixels of this line consisted of two linear parts with distinctly different slopes. This effect has been independent of the positioning of the wavelength, i.e., if the Cd line or the Fe line was in the center of the CCD array. The most likely explanation for this unusual behavior is a significant difference between the instrument width DELTAlambda{sub Instr} and the absorption line width DELTAlambda{sub Abs}, which is quite pronounced in the case of Fe. Using both parts of the calibration curves and simultaneous measurement at the line center and at the wings made it possible to extend the working range for the iron determination to more than three orders of magnitude.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kolmogorov, A., E-mail: anton.kolmogorov@gmail.com; Stupishin, N. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation); Atoian, G.; Ritter, J.; Zelenski, A. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Davydenko, V.; Ivanov, A. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation)

    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.

  2. Setup and proof of principle of SAPIS (Stored Atoms Polarized Ion Source), a novel source of polarized H{sup -}/D{sup -} ions; Aufbau und Funktionsnachweis von SAPIS (Stored Atoms Polarized Ion Source), einer neuartigen Quelle polarisierter H{sup -}/D{sup -}-Ionen

    Energy Technology Data Exchange (ETDEWEB)

    Emmerich, R.

    2007-02-14

    The objective of this work was the setup and the proof-of-principle of a new type of negative polarized hydrogen or deuterium ion source, which is based on the charge-exchange reaction (vector)H{sup 0}+Cs{sup 0}{yields}(vector)H{sup -}+Cs{sup +}, as for instance the Colliding-Beams-Source (CBS) at the Cooler Synchrotron COSY in Juelich. In contrast to the CBS, the use of a storage cell for the charge-exchange region promises an increase in H{sup -} current by at least an order of magnitude without considerable polarization losses. For these purposes, a new laboratory was equipped and both a polarized hydrogen/deuterium atomic beam source and an intense neutral cesium-beam source have been build-on. A Lambshift polarimeter, which allows the measurement of the nuclear polarization of the atomic as well as ionic beams, was completed with the construction of a new spin-filter. After commissioning and optimizing each of these sources, a storage cell was developed and installed in the charge-exchange region with a magnetic field. Additionally, components for the extraction, detection and analysis of the negative ion beam were installed. Following the decisive proof of principle, investigation of the properties of the storage cell, especially as to H recombination and depolarisation, was begun. Furthermore, a number of software programs was developed for the control and monitoring of different components of the sources as well as a universal measuring software for the complete installation, including the measurement and calculation of the beam polarization. At the same time, the remote control system of the Cologne source of polarized ions LASCO at the FN tandem accelerator was completely modernized. (orig.)

  3. Initial evaluation and comparison of plasma damage to atomic layer carbon materials using conventional and low T{sub e} plasma sources

    Energy Technology Data Exchange (ETDEWEB)

    Jagtiani, Ashish V.; Miyazoe, Hiroyuki; Chang, Josephine; Farmer, Damon B.; Engel, Michael; Neumayer, Deborah; Han, Shu-Jen; Engelmann, Sebastian U., E-mail: suengelm@us.ibm.com; Joseph, Eric A. [IBM, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Boris, David R.; Hernández, Sandra C.; Walton, Scott G. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Lock, Evgeniya H. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2016-01-15

    The ability to achieve atomic layer precision is the utmost goal in the implementation of atomic layer etch technology. Carbon-based materials such as carbon nanotubes (CNTs) and graphene are single atomic layers of carbon with unique properties and, as such, represent the ultimate candidates to study the ability to process with atomic layer precision and assess impact of plasma damage to atomic layer materials. In this work, the authors use these materials to evaluate the atomic layer processing capabilities of electron beam generated plasmas. First, the authors evaluate damage to semiconducting CNTs when exposed to beam-generated plasmas and compare these results against the results using typical plasma used in semiconductor processing. The authors find that the beam generated plasma resulted in significantly lower current degradation in comparison to typical plasmas. Next, the authors evaluated the use of electron beam generated plasmas to process graphene-based devices by functionalizing graphene with fluorine, nitrogen, or oxygen to facilitate atomic layer deposition (ALD). The authors found that all adsorbed species resulted in successful ALD with varying impact on the transconductance of the graphene. Furthermore, the authors compare the ability of both beam generated plasma as well as a conventional low ion energy inductively coupled plasma (ICP) to remove silicon nitride (SiN) deposited on top of the graphene films. Our results indicate that, while both systems can remove SiN, an increase in the D/G ratio from 0.08 for unprocessed graphene to 0.22 to 0.26 for the beam generated plasma, while the ICP yielded values from 0.52 to 1.78. Generally, while some plasma-induced damage was seen for both plasma sources, a much wider process window as well as far less damage to CNTs and graphene was observed when using electron beam generated plasmas.

  4. Application of atomic absorption spectrometry with continuous light source to analyze selected metals important for human health in different parts of oranges

    Directory of Open Access Journals (Sweden)

    Szwerc Wojciech

    2014-09-01

    Full Text Available The publication describes the application of high-resolution continuum source atomic absorption spectrometry (H-R CS AAS to determine some physiologically essential and toxic elements occurring in citrus fruits of different origins. Before analysis, the samples were mineralized using a mixture of deionized water and 69% nitric acid 3:1 (v/v in high pressure microwave digestion at 188°C during one hour.

  5. Effective atomic numbers and electron densities of some human tissues and dosimetric materials for mean energies of various radiation sources relevant to radiotherapy and medical applications

    Science.gov (United States)

    Kurudirek, Murat

    2014-09-01

    Effective atomic numbers, Zeff, and electron densities, neff, are convenient parameters used to characterise the radiation response of a multi-element material in many technical and medical applications. Accurate values of these physical parameters provide essential data in medical physics. In the present study, the effective atomic numbers and electron densities have been calculated for some human tissues and dosimetric materials such as Adipose Tissue (ICRU-44), Bone Cortical (ICRU-44), Brain Grey/White Matter (ICRU-44), Breast Tissue (ICRU-44), Lung Tissue (ICRU-44), Soft Tissue (ICRU-44), LiF TLD-100H, TLD-100, Water, Borosilicate Glass, PAG (Gel Dosimeter), Fricke (Gel Dosimeter) and OSL (Aluminium Oxide) using mean photon energies, Em, of various radiation sources. The used radiation sources are Pd-103, Tc-99, Ra-226, I-131, Ir-192, Co-60, 30 kVp, 40 kVp, 50 kVp (Intrabeam, Carl Zeiss Meditec) and 6 MV (Mohan-6 MV) sources. The Em values were then used to calculate Zeff and neff of the tissues and dosimetric materials for various radiation sources. Different calculation methods for Zeff such as the direct method, the interpolation method and Auto-Zeff computer program were used and agreements and disagreements between the used methods have been presented and discussed. It has been observed that at higher Em values agreement is quite satisfactory (Dif.<5%) between the adopted methods.

  6. A HBAR-oscillator-based 4.596~GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    CERN Document Server

    Daugey, Thomas; Martin, Gilles; Boudot, Rodolphe

    2015-01-01

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596~GHz frequency source. A 2.298~GHz signal, generated by an oscillator constructed around a thermally-controlled two-port AlN-sapphire HBAR resonator with a Q-factor of 24000 at 68$^{\\circ}$C, is frequency multiplied by 2 to 4.596~GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency (TCF) of the HBAR is measured to be $-23$~ppm/$^{\\circ}$C at 2.298~GHz. The measured phase noise of the 4.596~GHz source is $-105$~dBrad$^2$/Hz at 1~kHz offset and $-150$~dBrad$^2$/Hz at 100~kHz offset. The 4.596~GHz output signal is used as a local oscillator (LO) in a laboratory-prototype Cs microcell-based coherent population trapping (CPT) atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter (VCPS) implemented in the 2.298~GHz HBAR-oscillator loop, preventing the need for a high-power-consuming...

  7. Solar wind He pickup ions as source of tens-of-keV/n neutral He atoms observed by the HSTOF/SOHO detector

    CERN Document Server

    Grzedzielski, S; Czechowski, A; Hilchenbach, M

    2013-01-01

    Context. The HSTOF instrument on board SOHO satellite measures since 1996, during periods of low solar activity, weak fluxes of He atoms of 28-58 keV/n (helium energetic neutral atoms - He ENA). The probable source region is the inner heliosheath. Aims. Understand the emission mechanism of He ENA based on knowledge of heliosheath spatial extent and plasma content resulting from Voyager 1 & 2 measurements in the period posterior to termination shock crossings. Methods. He ENA are generated by charge-exchange neutralization of energetic helium ions on interstellar neutral H and He. Energy spectra of helium ions in the heliosheath are calculated by following the evolution of their velocity distribution functions when carried by, and undergoing binary interactions with, plasma constituents of a background flow whose particle populations are modeled to approximately render post-termination shock Voyager data. Results. The observed HSTOF He ENA form a higher energy part of general heliospheric He ENA fluxes and...

  8. The identification of autoionizing states of atomic chromium for the resonance ionization laser ion source of the ISOLDE radioactive ion beam facility

    Science.gov (United States)

    Day Goodacre, T.; Chrysalidis, K.; Fedorov, D. V.; Fedosseev, V. N.; Marsh, B. A.; Molkanov, P. L.; Rossel, R. E.; Rothe, S.; Seiffert, C.

    2017-03-01

    This paper presents the results of an investigation into autoionizing states of atomic chromium, in the service of the resonance ionization laser ion source (RILIS): the principal ion source of the ISOLDE radioactive ion beam facility based at CERN. The multi-step resonance photo-ionization process enables element selective ionization which, in combination with mass separation, allows isotope specific selectivity in the production of radioactive ion beams at ISOLDE. The element selective nature of the process requires a multi-step "ionization scheme" to be developed for each element. Using the method of in-source resonance ionization spectroscopy, an optimal three-step, three-resonance photo-ionization scheme originating from the 3d5(6S)4s a7S3 atomic ground state has been developed for chromium. The scheme uses an ionizing transition to one of the 15 newly observed autoionizing states reported here. Details of the spectroscopic studies are described and the new ionization scheme is summarized.

  9. New Directions in X-Ray Light Sources or Fiat Lux: what's under the dome and watching atoms with x-rays (LBNL Summer Lecture Series)

    Energy Technology Data Exchange (ETDEWEB)

    Falcone, Roger

    2008-07-15

    Summer Lecture Series 2008: Molecular movies of chemical reactions and material phase transformations need a strobe of x-rays, the penetrating light that reveals how atoms and molecules assemble in chemical and biological systems and complex materials. Roger Falcone, Director of the Advanced Light Source,will discuss a new generation of x ray sources that will enable a new science of atomic dynamics on ultrafast timescales.

  10. Growth of cubic III-nitrides by gas source MBE using atomic nitrogen plasma: GaN, AlGaN and AlN

    Science.gov (United States)

    Okumura, H.; Hamaguchi, H.; Koizumi, T.; Balakrishnan, K.; Ishida, Y.; Arita, M.; Chichibu, S.; Nakanishi, H.; Nagatomo, T.; Yoshida, S.

    1998-06-01

    Cubic GaN, AlGaN and AlN epilayers were grown on 3C-SiC(0 0 1) substrates by gas source molecular beam epitaxy using radio-frequency N 2 plasma containing atomic nitrogen species. Due to the enhancement of growth rate by this plasma source, cubic GaN epilayers with the thickness of several micrometers were obtained, and the quality of epilayers was so much improved that they showed an X-ray diffraction peak width as small as 9 min. Cubic Al xGa 1- xN and cubic AlN epilayers were also grown, and the variations of X-ray diffraction peak position and emission energy were observed according to the Al content.

  11. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    Energy Technology Data Exchange (ETDEWEB)

    Daugey, Thomas; Friedt, Jean-Michel; Martin, Gilles; Boudot, Rodolphe [FEMTO-ST, CNRS, UFC, 26 chemin de l’Epitaphe 25030 Besançon Cedex (France)

    2015-11-15

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad{sup 2}/Hz at 1 kHz offset and −150 dB rad{sup 2}/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10{sup −9} at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10{sup −11} τ{sup −1/2} up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance.

  12. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang

    2002-01-01

    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  13. Atoms Talking to SQUIDs

    CERN Document Server

    Hoffman, J E; Kim, Z; Wood, A K; Anderson, J R; Dragt, A J; Hafezi, M; Lobb, C J; Orozco, L A; Rolston, S L; Taylor, J M; Vlahacos, C P; Wellstood, F C

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  14. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  15. Heliosphere for a wide range of interstellar magnetic field strengths as a source of energetic neutral atoms

    CERN Document Server

    Czechowski, A; McComas, D J

    2015-01-01

    Observations of the energetic neutral atoms (ENAs) of heliospheric origin by IBEX differ from expectations based on heliospheric models. It was proposed that the structure of the heliosphere may be similar to the "two-stream" model derived in 1961 by Parker for the case of strong interstellar magnetic field. Using MHD simulations, we examine possible structure of the heliosphere for a wide range of interstellar magnetic field strengths, with different choices of interstellar medium and solar wind parameters. For the model heliospheres, we calculate the fluxes of ENAs created in the inner heliosheath, and compare with IBEX observations. We find that the plasma flow in the model heliospheres for strong interstellar field ($\\sim$20 $\\mu$G) has a "two-stream" structure, which remains visible down to $\\sim$5 $\\mu$G. The obtained ENA flux distribution show the features similar to the "split tail" effect observed by IBEX. In our model, the main cause of this effect is the two component (fast and slow) solar wind str...

  16. Simultaneous determination of iron and nickel in fluoropolymers by solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Soares, Bruno M; Santos, Rafael F; Bolzan, Rodrigo C; Muller, Edson I; Primel, Ednei G; Duarte, Fabio A

    2016-11-01

    This paper reports the development of a method of simultaneous determination of iron and nickel in fluoropolymers by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) with direct solid sampling. In order to carry out simultaneous measurements, both the main resonance line of nickel (232.003nm) and the adjacent secondary line of iron (232.036nm) were monitored in the same spectral window. The proposed method was optimized with a perfluoroalkoxy (PFA) sample and was applied to the determination of iron and nickel in fluorinated ethylene propylene (FEP) and modified polytetrafluoroethylene (PTFE-TFM) samples. Pyrolysis and atomization temperatures, as well as the use of Pd and H2 (during pyrolysis) as chemical modifiers, were carefully investigated. Compromise temperatures for pyrolysis and atomization of both analytes were achieved at 800 and 2300°C, respectively, using only 0.5Lmin(-1) H2 as chemical modifier during pyrolysis. Calibration curves were performed with aqueous standards by using a single solution which contained both analytes. Limits of detection were 221 and 9.6ngg(-1) for iron and nickel, respectively. Analyte concentrations in all samples ranged from 3.53 to 12.4µgg(-1) for iron and from 37 to 78ngg(-1) for nickel, with relative standard deviation less than 19%. Accuracy was evaluated by comparing these results with those obtained by inductively coupled plasma mass spectrometry after sample digestion by microwave-induced combustion and no significant statistical difference was observed.

  17. Monitoring and Method development of Hg in Istanbul Airborne Particulates by Solid Sampling Continuum Source-High Resolution Electrothermal Atomic Absorption Spectromerty

    Directory of Open Access Journals (Sweden)

    Soydemir E.

    2014-07-01

    Full Text Available In this work, a method has been developed and monitoring for the determination of mercury in PM2.5 airborne particulates by solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry. The PM2.5 airborne particulates were collected on quartz filters using high volume samplers (500 L/min in Istanbul (Turkey for 96 hours every month in one year. At first, experimental conditions as well as the validation tests were optimized using collected filter. For this purpose, the effects of atomization temperature, amount of sample intoduced in to the furnace, addition of acids and/or KMnO4 on the sample, covering of graphite tube and platform or using of Ag nanoparticulates, Au nanoparticulates, and Pd solutions on the accuracy and precision were investigated. After optimization of the experimental conditions, the mercury concentrations were determined in the collected filter. The filters with PM2.5 airborne particulates were dried, divided into small fine particles and then Hg concentrations were determined directly. In order to eliminate any error due to the sensitivity difference between aqueous standards and solid samples, the quantification was performed using solid calibrants. The limit of detection, based on three times the standard deviations for ten atomizations of an unused filter, was 30 ng/g. The Hg content was dependent on the sampling site, season etc, ranging from

  18. H2 Molecular Clusters with Embedded Molecules and Atoms as the Source of the Diffuse Interstellar Bands

    Science.gov (United States)

    Bernstein, L. S.; Clark, F. O.; Lynch, D. K.

    2013-05-01

    We suggest that the diffuse interstellar bands (DIBs) arise from absorption lines of electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion ("seed"), embedded in a single-layer shell of H2 molecules. Less abundant variants of the cluster, including two seed molecules and/or a two-layer shell of H2 molecules, may also occur. The lines are broadened, blended, and wavelength-shifted by interactions between the seed and surrounding H2 shell. We refer to these clusters as contaminated H2 clusters (CHCs). We show that CHC spectroscopy matches the diversity of observed DIB spectral profiles and provides good fits to several DIB profiles based on a rotational temperature of 10 K. CHCs arise from ~centimeter-sized, dirty H2 ice balls, called contaminated H2 ice macro-particles (CHIMPs), formed in cold, dense, giant molecular clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Attractive interactions, arising from Van der Waals and ion-induced dipole potentials, between the seeds and H2 molecules enable CHIMPs to attain centimeter-sized dimensions. When an ultraviolet (UV) photon is absorbed in the outer layer of a CHIMP, it heats the icy matrix and expels CHCs into the ISM. While CHCs are quickly destroyed by absorbing UV photons, they are replenished by the slowly eroding CHIMPs. Since CHCs require UV photons for their release, they are most abundant at, but not limited to, the edges of UV-opaque molecular clouds, consistent with the observed, preferred location of DIBs. An inherent property of CHCs, which can be characterized as nanometer size, spinning, dipolar dust grains, is that they emit in the radio-frequency region. We also show that the CHCs offer a natural explanation for the anomalous microwave emission feature in the ~10-100 GHz spectral region.

  19. A comparative study on electrical characteristics of crystalline AlN thin films deposited by ICP and HCPA-sourced atomic layer deposition

    Science.gov (United States)

    Altuntas, Halit; Bayrak, Turkan

    2016-12-01

    In this work, we aimed to investigate the effects of two different plasma sources on the electrical properties of low-temperature plasma-assisted atomic layer deposited (PA-ALD) AlN thin films. To compare the electrical properties, 50 nm thick AlN films were grown on p-type Si substrates at 200 °C by using an inductively coupled RF-plasma (ICP) and a stainless steel hollow cathode plasma-assisted (HCPA) ALD systems. Al/AlN/p-Si metal-insulator-semiconductor (MIS) capacitor devices were fabricated and capacitance versus voltage (C-V) and current-voltage (I-V) measurements performed to assess the basic important electrical parameters such as dielectric constant, effective charge density, flat-band voltage, breakdown field, and threshold voltage. In addition, structural properties of the films were presented and compared. The results show that although HCPA-ALD deposited AlN thin films has structurally better and has a lower effective charge density (N eff ) value than ICP-ALD deposited AlN films, those films have large leakage current, low dielectric constant, and low breakdown field. This situation was attributed to the involvement of Si atoms into the AlN layers during the HCPA-ALD processing leads to additional current path at AlN/Si interface and might impair the electrical properties.

  20. Evaluation of solid sampling for determination of Mo, Ni, Co, and V in soil by high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Babos, Diego Victor; Barros, Ariane Isis; Ferreira, Edilene Cristina; Neto, José Anchieta Gomes

    2017-04-01

    New methods are proposed for the determination of Mo, Ni, Co, and V in soils using high-resolution continuum source graphite furnace atomic absorption spectrometry with direct solid sampling. Cobalt and V were simultaneously determined, and different analytical lines of Ni and V were monitored to adjust sensitivity for each sample. Accuracy was checked by means of soil certified reference materials, and also by flame atomic absorption spectrometry as comparative technique. The results for Mo, Ni, Co, and V found by proposed methods were in agreement with certified values and with those obtained by the comparative technique at 95% confidence level. The concentrations found in different soil samples were in the ranges 0.19-1.84 mg kg- 1 (Mo), 9.2-22.7 mg kg- 1 (Ni), 1.1-10.7 mg kg- 1 (Co), and 35.6-426.1 mg kg- 1 (V). The relative standard deviations were in the ranges 3.2-10% (Mo), 2.8-9.8% (Ni), 4.0-9.2% (Co), and 1.2-8.0% (V). The limits of quantification for Mo, Ni, Co, and V were 0.027, 0.071, 0.15, and 1.43 ng, respectively.

  1. Investigating effects of sample pretreatment on protein stability using size-exclusion chromatography and high-resolution continuum source atomic absorption spectrometry.

    Science.gov (United States)

    Rakow, Tobias; El Deeb, Sami; Hahne, Thomas; El-Hady, Deia Abd; AlBishri, Hassan M; Wätzig, Hermann

    2014-09-01

    In this study, size-exclusion chromatography and high-resolution atomic absorption spectrometry methods have been developed and evaluated to test the stability of proteins during sample pretreatment. This especially includes different storage conditions but also adsorption before or even during the chromatographic process. For the development of the size exclusion method, a Biosep S3000 5 μm column was used for investigating a series of representative model proteins, namely bovine serum albumin, ovalbumin, monoclonal immunoglobulin G antibody, and myoglobin. Ambient temperature storage was found to be harmful to all model proteins, whereas short-term storage up to 14 days could be done in an ordinary refrigerator. Freezing the protein solutions was always complicated and had to be evaluated for each protein in the corresponding solvent. To keep the proteins in their native state a gentle freezing temperature should be chosen, hence liquid nitrogen should be avoided. Furthermore, a high-resolution continuum source atomic absorption spectrometry method was developed to observe the adsorption of proteins on container material and chromatographic columns. Adsorption to any container led to a sample loss and lowered the recovery rates. During the pretreatment and high-performance size-exclusion chromatography, adsorption caused sample losses of up to 33%.

  2. A comparative study on electrical characteristics of crystalline AlN thin films deposited by ICP and HCPA-sourced atomic layer deposition

    Science.gov (United States)

    Altuntas, Halit; Bayrak, Turkan

    2017-03-01

    In this work, we aimed to investigate the effects of two different plasma sources on the electrical properties of low-temperature plasma-assisted atomic layer deposited (PA-ALD) AlN thin films. To compare the electrical properties, 50 nm thick AlN films were grown on p-type Si substrates at 200 °C by using an inductively coupled RF-plasma (ICP) and a stainless steel hollow cathode plasma-assisted (HCPA) ALD systems. Al/AlN/ p-Si metal-insulator-semiconductor (MIS) capacitor devices were fabricated and capacitance versus voltage ( C- V) and current-voltage ( I- V) measurements performed to assess the basic important electrical parameters such as dielectric constant, effective charge density, flat-band voltage, breakdown field, and threshold voltage. In addition, structural properties of the films were presented and compared. The results show that although HCPA-ALD deposited AlN thin films has structurally better and has a lower effective charge density ( N eff ) value than ICP-ALD deposited AlN films, those films have large leakage current, low dielectric constant, and low breakdown field. This situation was attributed to the involvement of Si atoms into the AlN layers during the HCPA-ALD processing leads to additional current path at AlN/Si interface and might impair the electrical properties.

  3. Evaluation of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for direct determination of chromium in medicinal plants

    Energy Technology Data Exchange (ETDEWEB)

    Virgilio, Alex; Nobrega, Joaquim A. [Department of Chemistry, Federal University of Sao Carlos, Post Office Box 676, 13560-970, Sao Carlos-SP (Brazil); Rego, Jardes F. [Department of Analytical Chemistry, Institute of Chemistry, Sao Paulo State University-UNESP, Post Office Box 355, 14801-970, Araraquara-SP (Brazil); Neto, Jose A. Gomes, E-mail: anchieta@iq.unesp.br [Department of Analytical Chemistry, Institute of Chemistry, Sao Paulo State University-UNESP, Post Office Box 355, 14801-970, Araraquara-SP (Brazil)

    2012-12-01

    A method for Cr determination in medicinal plants using direct solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry was developed. Modifiers were dispensable. Pyrolysis and atomization temperatures were 1500 Degree-Sign C and 2400 Degree-Sign C, respectively. Slopes of calibration curves (50-750 pg Cr, R{sup 2} > 0.999) using aqueous and solid standards coincides in 96%, indicated feasibility of aqueous calibration for solid sampling of medicinal plants. Accuracy was checked by analysis of four plant certified reference materials. Results were in agreement at 95% confidence level with certified and non-certified values. Ten samples of medicinal plants were analyzed and Cr contents were in the 1.3-17.7 {mu}g g{sup -1} Cr range. The highest RSD (n = 5) was 15.4% for the sample Melissa officinalis containing 13.9 {+-} 2.1 {mu}g g{sup -1} Cr. The limit of detection was 3.3 ng g{sup -1} Cr. - Highlights: Black-Right-Pointing-Pointer Direct solid sampling is first time employed for Cr in plant materials. Black-Right-Pointing-Pointer Calibration curves with liquids and solids are coincident. Black-Right-Pointing-Pointer Microanalysis of plants for Cr is validated by reference materials. Black-Right-Pointing-Pointer The proposed HR-CS GF AAS method is environmental friendly.

  4. Evaluation of solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry for direct determination of chromium in medicinal plants

    Science.gov (United States)

    Virgilio, Alex; Nóbrega, Joaquim A.; Rêgo, Jardes F.; Neto, José A. Gomes

    2012-12-01

    A method for Cr determination in medicinal plants using direct solid sampling graphite furnace high-resolution continuum source atomic absorption spectrometry was developed. Modifiers were dispensable. Pyrolysis and atomization temperatures were 1500 °C and 2400 °C, respectively. Slopes of calibration curves (50-750 pg Cr, R2 > 0.999) using aqueous and solid standards coincides in 96%, indicated feasibility of aqueous calibration for solid sampling of medicinal plants. Accuracy was checked by analysis of four plant certified reference materials. Results were in agreement at 95% confidence level with certified and non-certified values. Ten samples of medicinal plants were analyzed and Cr contents were in the 1.3-17.7 μg g- 1 Cr range. The highest RSD (n = 5) was 15.4% for the sample Melissa officinalis containing 13.9 ± 2.1 μg g- 1 Cr. The limit of detection was 3.3 ng g- 1 Cr.

  5. Small Atomic Orbital Basis Set First-Principles Quantum Chemical Methods for Large Molecular and Periodic Systems: A Critical Analysis of Error Sources.

    Science.gov (United States)

    Sure, Rebecca; Brandenburg, Jan Gerit; Grimme, Stefan

    2016-04-01

    In quantum chemical computations the combination of Hartree-Fock or a density functional theory (DFT) approximation with relatively small atomic orbital basis sets of double-zeta quality is still widely used, for example, in the popular B3LYP/6-31G* approach. In this Review, we critically analyze the two main sources of error in such computations, that is, the basis set superposition error on the one hand and the missing London dispersion interactions on the other. We review various strategies to correct those errors and present exemplary calculations on mainly noncovalently bound systems of widely varying size. Energies and geometries of small dimers, large supramolecular complexes, and molecular crystals are covered. We conclude that it is not justified to rely on fortunate error compensation, as the main inconsistencies can be cured by modern correction schemes which clearly outperform the plain mean-field methods.

  6. Development of a compact thermal lithium atom beam source for measurements of electron velocity distribution function anisotropy in electron cyclotron resonance plasmas.

    Science.gov (United States)

    Nishioka, T; Shikama, T; Nagamizo, S; Fujii, K; Zushi, H; Uchida, M; Iwamae, A; Tanaka, H; Maekawa, T; Hasuo, M

    2013-07-01

    The anisotropy of the electron velocity distribution function (EVDF) in plasmas can be deduced from the polarization of emissions induced by anisotropic electron-impact excitation. In this paper, we develop a compact thermal lithium atom beam source for spatially resolved measurements of the EVDF anisotropy in electron cyclotron resonance (ECR) plasmas. The beam system is designed such that the ejected beam has a slab shape, and the beam direction is variable. The divergence and flux of the beam are evaluated by experiments and calculations. The developed beam system is installed in an ECR plasma device with a cusp magnetic field, and the LiI 2s-2p emission (670.8 nm) is observed in low-pressure helium plasma. The two-dimensional distributions of the degree and direction of the polarization in the LiI emission are measured by a polarization imaging system. The evaluated polarization distribution suggests the spatial variation of the EVDF anisotropy.

  7. Detailed study of an efficient blue laser source by second-harmonic generation in a semimonolithic cavity for the cooling of strontium atoms.

    Science.gov (United States)

    Klappauf, Bruce G; Bidel, Yannick; Wilkowski, David; Chanelière, Thierry; Kaiser, Robin

    2004-04-20

    We have constructed a blue laser source consisting of an amplified, grating tuned diode laser that is frequency doubled by a KNbO3 crystal in a compact standing wave cavity and produces as much as 200 mW of internal second-harmonic power. We have analyzed the unusual characteristics of this standing wave cavity to clarify the advantages and disadvantages of this configuration as an alternative to a ring cavity for second-harmonic generation. We emphasize its efficiency and stability and the fact that it has an inherent walk-off compensation, similar to twin crystal configurations. We demonstrate its utility for laser cooling and trapping of earth alkalis by stabilizing the laser to the 461-nm transition of strontium, using a heat pipe, and then forming a magneto-optic trap of strontium from a Zeeman-slowed atomic beam.

  8. Detailed Study of an Efficient Blue Laser Source by Second-Harmonic Generation in a Semimonolithic Cavity for the Cooling of Strontium Atoms

    Science.gov (United States)

    Klappauf, Bruce G.; Bidel, Yannick; Wilkowski, David; Chanelière, Thierry; Kaiser, Robin

    2004-04-01

    We have constructed a blue laser source consisting of an amplified, grating tuned diode laser that is frequency doubled by a KNbO3 crystal in a compact standing wave cavity and produces as much as 200 mW of internal second-harmonic power. We have analyzed the unusual characteristics of this standing wave cavity to clarify the advantages and disadvantages of this configuration as an alternative to a ring cavity for second-harmonic generation. We emphasize its efficiency and stability and the fact that it has an inherent walk-off compensation, similar to twin crystal configurations. We demonstrate its utility for laser cooling and trapping of earth alkalis by stabilizing the laser to the 461-nm transition of strontium, using a heat pipe, and then forming a magneto-optic trap of strontium from a Zeeman-slowed atomic beam.

  9. Inactivation of Penicillium digitatum Spores by a High-Density Ground-State Atomic Oxygen-Radical Source Employing an Atmospheric-Pressure Plasma

    Science.gov (United States)

    Iseki, Sachiko; Hashizume, Hiroshi; Jia, Fengdong; Takeda, Keigo; Ishikawa, Kenji; Ohta, Takayuki; Ito, Masafumi; Hori, Masaru

    2011-11-01

    Penicillium digitatum spores were inactivated using an oxygen-radical source that supplies only neutral oxygen radicals. Vacuum ultraviolet absorption spectroscopy was used to measure the ground-state atomic oxygen [O (3Pj)] densities and they were estimated to be in the range of 1014-1015 cm-3. The inactivation rate of P. digitatum spores was correlated with the O (3Pj) density. The result indicates that O (3Pj) is the dominant species in the inactivation. The inactivation rate constant of P. digitatum spores by O (3Pj) was estimated to be on the order of 10-17 cm3 s-1 from the measured O (3Pj) densities and inactivation rates.

  10. Sources

    OpenAIRE

    2015-01-01

    SOURCES MANUSCRITES Archives nationales Rôles de taille 1768/71 Z1G-344/18 Aulnay Z1G-343a/02 Gennevilliers Z1G-340/01 Ivry Z1G-340/05 Orly Z1G-334c/09 Saint-Remy-lès-Chevreuse Z1G-344/18 Sevran Z1G-340/05 Thiais 1779/80 Z1G-391a/18 Aulnay Z1G-380/02 Gennevilliers Z1G-385/01 Ivry Z1G-387b/05 Orly Z1G-388a/09 Saint-Remy-lès-Chevreuse Z1G-391a/18 Sevran Z1G-387b/05 Thiais 1788/89 Z1G-451/18 Aulnay Z1G-452/21 Chennevières Z1G-443b/02 Gennevilliers Z1G-440a/01 Ivry Z1G-452/17 Noiseau Z1G-445b/05 ...

  11. Determination of mercury in airborne particulate matter collected on glass fiber filters using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sampling

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Rennan G.O., E-mail: rgoa01@terra.com.br [Laboratorio de Quimica Analitica Ambiental, Departamento de Quimica, Universidade Federal de Sergipe, Campus Sao Cristovao, 49.100-000, Sao Cristovao, SE (Brazil); Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Vignola, Fabiola; Castilho, Ivan N.B. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Borges, Daniel L.G.; Welz, Bernhard [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, SC (Brazil); Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Vale, Maria Goreti R. [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, RS (Brazil); Smichowski, Patricia [Comision Nacional de Energia Atomica (CNEA) and Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina); Ferreira, Sergio L.C. [Instituto Nacional de Ciencia e Tecnologia do CNPq, INCT de Energia e Ambiente, Universidade Federal da Bahia, 40170-115 Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal da Bahia, 40170-290, Salvador, BA (Brazil); Becker-Ross, Helmut [Leibniz-Institut fuer Analytische Wissenschaften-ISAS-e.V., Department Berlin, 12489 Berlin (Germany)

    2011-05-15

    A study has been undertaken to assess the capability of high-resolution continuum source graphite furnace atomic absorption spectrometry for the determination of mercury in airborne particulate matter (APM) collected on glass fiber filters using direct solid sampling. The main Hg absorption line at 253.652 nm was used for all determinations. The certified reference material NIST SRM 1648 (Urban Particulate Matter) was used to check the accuracy of the method, and good agreement was obtained between published and determined values. The characteristic mass was 22 pg Hg. The limit of detection (3{sigma}), based on ten atomizations of an unexposed filter, was 40 ng g{sup -1}, corresponding to 0.12 ng m{sup -3} in the air for a typical air volume of 1440 m{sup 3} collected within 24 h. The limit of quantification was 150 ng g{sup -1}, equivalent to 0.41 ng m{sup -3} in the air. The repeatability of measurements was better than 17% RSD (n = 5). Mercury concentrations found in filter samples loaded with APM collected in Buenos Aires, Argentina, were between < 40 ng g{sup -1} and 381 {+-} 24 ng g{sup -1}. These values correspond to a mercury concentration in the air between < 0.12 ng m{sup -3} and 1.47 {+-} 0.09 ng m{sup -3}. The proposed procedure was found to be simple, fast and reliable, and suitable as a screening procedure for the determination of mercury in APM samples.

  12. Determinations of Sb and Mo in Cairo's dust using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

    Science.gov (United States)

    Shaltout, Abdallah A.; Welz, Bernhard; Castilho, Ivan N. B.

    2013-12-01

    The present work describes the determination of Sb and Mo in dust deposited on tree leaves using direct solid sample analysis. Nineteen air particulate samples were collected from different districts of Cairo and surrounding cities. Since some samples have been taken from places less exposed to the pollution factors, the present study allows the comparison of air quality between high and low polluted areas. High-resolution continuum source graphite furnace atomic absorption spectrometry has been investigated, using direct solid sample analysis. The optimum pyrolysis and atomization temperatures for Sb were found to be 800 °C and 1900 °C, and 1200 °C and 2650 °C, respectively for Mo. The limits of detection and quantification for both, Sb and Mo, were 15 μg g-1 and 50 ng g-1, respectively. The characteristic mass at was found to be m0 = 38 pg for Sb (217.582 nm) and m0 = 28 pg for Mo (313.259 nm). The results obtained for three certified reference materials of urban particulate matter confirmed the validity of the investigated method. The content of Sb varied between 213 ± 1.3 μg g-1 and 1117 ± 230 μg g-1 with an average of 667 ± 339 μg g-1. On the other hand, the Mo content varied from 113 ± 2.3 μg g-1 to 361 ± 51 μg g-1 and its average value equals 190 ± 62 μg g-1.

  13. Direct and simultaneous determination of Cr and Fe in crude oil using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dittert, Ingrid M. [Departamento de Quimica, Universidade Federal de Santa Catarina, Campus Universitario, Trindade, 88040-900, Florianopolis, SC (Brazil); Silva, Jessee S.A. [Centro Federal de Educacao Tecnologica de Santa Catarina, Florianopolis, SC (Brazil); Araujo, Rennan G.O. [Departamento de Quimica, Universidade Federal de Santa Catarina, Campus Universitario, Trindade, 88040-900, Florianopolis, SC (Brazil)], E-mail: rgoa01@terra.com.br; Curtius, Adilson J.; Welz, Bernhard [Departamento de Quimica, Universidade Federal de Santa Catarina, Campus Universitario, Trindade, 88040-900, Florianopolis, SC (Brazil); Becker-Ross, Helmut [ISAS, Institute for Analytical Sciences, Department of Interface Spectroscopy, Albert-Einstein-Str. 9, 12489 Berlin (Germany)

    2009-06-15

    A simple, fast and sensitive direct method for the simultaneous determination of Cr and Fe in crude oil samples is proposed using high-resolution continuum source graphite furnace atomic absorption spectrometry. No sample preparation is used except for a 10-minute homogenization in an ultrasonic bath. Aliquots of 0.1-4 mg of the samples are weighed onto solid sampling platforms and analyzed directly using aqueous standards for calibration. The simultaneous determination was possible because there is a secondary Fe line at 358.120 nm in the vicinity of the most sensitive Cr line at 357.868 nm, and both absorption lines were within the wavelength interval covered by the linear charge-coupled device array detector. It has also been of advantage that the sensitivity ratio between the two analytical lines corresponded roughly to the concentration ratio of the two elements found in crude oil, and that both analytes have very similar volatility, so that no compromises had to be made regarding pyrolysis and atomization temperatures. Two oil reference materials have been analyzed and the results were in agreement with the certified or reported values. Characteristic masses of 3.6 pg and 0.5 ng were obtained for Cr and Fe, respectively. The limits of detection (3{sigma}, n = 10) were 1 {mu}g kg{sup - 1} for Cr and 0.6 mg kg{sup - 1} for Fe, and the precision, expressed as the relative standard deviation, ranged from 4 to 20%, which is often acceptable for a rapid direct analytical procedure. Five crude oils samples were analyzed.

  14. Direct and simultaneous determination of Cr and Fe in crude oil using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Dittert, Ingrid M.; Silva, Jessee S. A.; Araujo, Rennan G. O.; Curtius, Adilson J.; Welz, Bernhard; Becker-Ross, Helmut

    2009-06-01

    A simple, fast and sensitive direct method for the simultaneous determination of Cr and Fe in crude oil samples is proposed using high-resolution continuum source graphite furnace atomic absorption spectrometry. No sample preparation is used except for a 10-minute homogenization in an ultrasonic bath. Aliquots of 0.1-4 mg of the samples are weighed onto solid sampling platforms and analyzed directly using aqueous standards for calibration. The simultaneous determination was possible because there is a secondary Fe line at 358.120 nm in the vicinity of the most sensitive Cr line at 357.868 nm, and both absorption lines were within the wavelength interval covered by the linear charge-coupled device array detector. It has also been of advantage that the sensitivity ratio between the two analytical lines corresponded roughly to the concentration ratio of the two elements found in crude oil, and that both analytes have very similar volatility, so that no compromises had to be made regarding pyrolysis and atomization temperatures. Two oil reference materials have been analyzed and the results were in agreement with the certified or reported values. Characteristic masses of 3.6 pg and 0.5 ng were obtained for Cr and Fe, respectively. The limits of detection (3 σ, n = 10) were 1 µg kg - 1 for Cr and 0.6 mg kg - 1 for Fe, and the precision, expressed as the relative standard deviation, ranged from 4 to 20%, which is often acceptable for a rapid direct analytical procedure. Five crude oils samples were analyzed.

  15. A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bechlin, Marcos André; Fortunato, Felipe Manfroi; Moutinho da Silva, Ricardo; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta, E-mail: anchieta@iq.unesp.br

    2014-11-01

    The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500–5000 mg L{sup −1} N (r = 0.9994), 100–2000 mg L{sup −1} P (r = 0.9946), and 100–2500 mg L{sup −1} K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO{sub 3}{sup −}-N), 95–103% (NH{sub 4}{sup +}-N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively. - Highlights: • A single technique is proposed to analyze NPK fertilizer. • HR-CS FAAS is proposed for the first time for N, P and K determination in fertilizers. • The method employs the same sample preparation and dilution for the three analytes. • Addition of H{sub 2}O{sub 2} allows analysis of fertilizers with different nitrogen species. • Proposal provides advantages over traditional methods in terms of cost and time.

  16. Direct determination of chromium in infant formulas employing high-resolution continuum source electrothermal atomic absorption spectrometry and solid sample analysis.

    Science.gov (United States)

    Silva, Arlene S; Brandao, Geovani C; Matos, Geraldo D; Ferreira, Sergio L C

    2015-11-01

    The present work proposed an analytical method for the direct determination of chromium in infant formulas employing the high-resolution continuum source electrothermal atomic absorption spectrometry combined with the solid sample analysis (SS-HR-CS ET AAS). Sample masses up to 2.0mg were directly weighted on a solid sampling platform and introduced into the graphite tube. In order to minimize the formation of carbonaceous residues and to improve the contact of the modifier solution with the solid sample, a volume of 10 µL of a solution containing 6% (v/v) H2O2, 20% (v/v) ethanol and 1% (v/v) HNO3 was added. The pyrolysis and atomization temperatures established were 1600 and 2400 °C, respectively, using magnesium as chemical modifier. The calibration technique was evaluated by comparing the slopes of calibration curves established using aqueous and solid standards. This test revealed that chromium can be determined employing the external calibration technique using aqueous standards. Under these conditions, the method developed allows the direct determination of chromium with limit of quantification of 11.5 ng g(-1), precision expressed as relative standard deviation (RSD) in the range of 4.0-17.9% (n=3) and a characteristic mass of 1.2 pg of chromium. The accuracy was confirmed by analysis of a certified reference material of tomato leaves furnished by National Institute of Standards and Technology. The method proposed was applied for the determination of chromium in five different infant formula samples. The chromium content found varied in the range of 33.9-58.1 ng g(-1) (n=3). These samples were also analyzed employing ICP-MS. A statistical test demonstrated that there is no significant difference between the results found by two methods. The chromium concentrations achieved are lower than the maximum limit permissible for chromium in foods by Brazilian Legislation.

  17. Investigation of spectral interferences in the determination of lead in fertilizers and limestone samples using high-resolution continuum source graphite furnace atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; François, Luciane L.; Jesus, Alexandre de [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Dessuy, Morgana B., E-mail: mbdessuy@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Andrade, Jailson B. de [Instituto Nacional de Ciência e Tecnologia do CNPq — INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil)

    2014-11-01

    In the present work, spectral interferences on the determination of lead in fertilizer and limestone samples were investigated using high-resolution continuum source graphite furnace atomic absorption spectrometry at the main analytical lines: 217.001 and 283.306 nm. For these investigations, samples were introduced into the furnace as slurry together with a mixture of Pd and Mg as chemical modifier. Spectral interferences were observed for some samples at both analytical lines. In order to verify whether a wet digestion procedure would avoid these interferences, a reference method for wet digestion of fertilizers was employed as an alternative sample preparation procedure. However, the same interferences were also observed in the digested samples. In order to identify and eliminate the fine-structured background using a least-squares background correction, reference spectra were generated using the combination of different species. The use of the latter technique allowed the elimination of spectral interferences for most of the investigated samples, making possible the determination of lead in fertilizer and limestone samples free of interferences. The best results were found using a reference spectrum of NH{sub 4}H{sub 2}PO{sub 4} at 217.001 nm, and a mixture of H{sub 2}SO{sub 4} + Ca and HNO{sub 3} + Ca at the 283.306 nm line. The accuracy of the method was evaluated using a certified reference material “Trace Elements in Multi-Nutrient Fertilizer”. Similar results were obtained using line source graphite furnace atomic absorption spectrometry with Zeeman-effect background correction, indicating that the latter technique was also capable to correct the spectral interferences, at least in part. - Highlights: • Spectral interferences on the determination of lead in fertilizers and limestone. • The analytical lines at 217.001 nm and 283.306 nm using HR-CS GF AAS. • Various combinations of compounds were used to create reference spectra. • LSBC

  18. Method development for the determination of cadmium in fertilizer samples using high-resolution continuum source graphite furnace atomic absorption spectrometry and slurry sampling

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Aline R. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia do CNPq-INCT de Energia e Ambiente, Universidade Federal de Bahia, Salvador, BA (Brazil); Becker, Emilene M. [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Lequeux, Celine [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Universite de Rennes 1, Rennes (France); Vale, Maria Goreti R., E-mail: mgrvale@ufrgs.br [Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciencia e Tecnologia do CNPq-INCT de Energia e Ambiente, Universidade Federal de Bahia, Salvador, BA (Brazil); Ferreira, Sergio L.C. [Instituto Nacional de Ciencia e Tecnologia do CNPq-INCT de Energia e Ambiente, Universidade Federal de Bahia, Salvador, BA (Brazil); Instituto de Quimica, Universidade Federal da Bahia, Salvador, Bahia 40170-290 (Brazil); Welz, Bernhard [Instituto Nacional de Ciencia e Tecnologia do CNPq-INCT de Energia e Ambiente, Universidade Federal de Bahia, Salvador, BA (Brazil); Departamento de Quimica, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil)

    2011-07-15

    The determination of cadmium (Cd) in fertilizers is of major interest, as this element can cause growth problems in plants, and also affect animals and humans. High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) with charge-coupled device (CCD) array detection overcomes several of the limitations encountered with conventional line source AAS, especially the problem of accurate background measurement and correction. In this work an analytical method has been developed to determine Cd in fertilizer samples by HR-CS GF AAS using slurry sampling. Both a mixture of 10 {mu}g Pd + 6 {mu}g Mg in solution and 400 {mu}g of iridium as permanent modifier have been investigated and aqueous standards were used for calibration. Pyrolysis and atomization temperatures were 600 {sup o}C and 1600 {sup o}C for the Pd-Mg modifier, and 500 deg. C and 1600 deg. C for Ir, respectively. The results obtained for Cd in the certified reference material NIST SRM 695 (Trace Elements in Multi-Nutrient Fertilizer) of 16.7 {+-} 1.3 {mu}g g{sup -1} and 16.4 {+-} 0.75 {mu}g g{sup -1} for the Pd-Mg and Ir modifier, respectively, were statistically not different from the certified value of 16.9 {+-} 0.2 {mu}g g{sup -1} on a 95% confidence level; however, the results obtained with the Ir modifier were significantly lower than those for the Pd-Mg modifier for most of the samples. The characteristic mass was 1.0 pg for the Pd-Mg modifier and 1.1 pg Cd for the Ir modifier, and the correlation coefficients (R{sup 2}) of the calibration were > 0.99. The instrumental limits of detection were 7.5 and 7.9 ng g{sup -1}, and the limits of quantification were 25 and 27 ng g{sup -1} for Pd-Mg and Ir, respectively, based on a sample mass of 5 mg. The cadmium concentration in the investigated samples was between 0.07 and 5.5 {mu}g g{sup -1} Cd, and hence below the maximum value of 20 {mu}g g{sup -1} Cd permitted by Brazilian legislation.

  19. Fast arsenic speciation in water by on-site solid phase extraction and high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Mihucz, Victor G.; Bencs, László; Koncz, Kornél; Tatár, Enikő; Weiszburg, Tamás; Záray, Gyula

    2017-02-01

    A method of high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS-GFAAS), combined with on-site separation/solid phase extraction (SPE) has been developed for the speciation of inorganic As (iAs) in geothermal and drinking water samples. The HR-CS-GFAAS calibration curves were linear up to 200 μg/L As, but using second order polynomial fitting, accurate calibration could be performed up to 500 μg/L. It has been demonstrated that sample pH should not be higher than 8 for an accurate speciation of As(V) with a recovery of ≈ 95%. Geothermal water had fairly high salt content (≈ 2200 mg/L) due to the presence of chlorides and sulfates at mg/L levels. Therefore, a two-fold dilution of these types of samples before SPE is recommended, especially, for total As determinations, when the As concentration is as high as 400 μg/L. For drinking water, sampled from public wells with records of As concentrations higher than the 10 μg/L in the past, the reduction of As contamination below the WHO's health limit value could be observed. However, the electrical conductivity was close to 2500 μS/cm, i.e., the guideline limit for drinking water, which was due to their higher chloride content. The proposed fit-for-purpose SPE-HR-CS-GFAAS method could be a candidate for screening drinking water quality.

  20. Validated method for the determination of platinum from a liposomal source (SPI-77) in human plasma using graphite furnace Zeeman atomic absorption spectrometry.

    Science.gov (United States)

    Meerum Terwogt, J M; Tibben, M M; Welbank, H; Schellens, J H; Beijnen, J H

    2000-02-01

    A sensitive analytical method based on flameless atomic absorption spectrometry with Zeeman correction has been validated for the quantitative determination in human plasma of platinum originating from cisplatin in a liposomal source, SPI-77. The performance of the method was acceptable over a sample concentration range of 0. 125-1.25 micromol platinum/L and the lower limit of quantification was determined to be 1.25 micromol platinum/L in undiluted clinical samples. The performance data of the assay were investigated using both a calibration curve with carboplatin in plasma ultrafiltrate and diluted human plasma samples spiked with SPI-77. The recoveries, between-day and the within-day precisions of both methods of calibration were not significantly different allowing carboplatin ultrafiltrate calibration standards to be used to quantify platinum derived from SPI-77 in human plasma. Apparently, the liposomal formulation had no significant influence on the determination of platinum. The usefulness of the presented method was demonstrated in a phase I clinical and pharmacokinetic study. In addition, in vitro experiments were carried out to determine the distribution of SPI-77 in blood. The results indicated that platinum from SPI-77 mainly concentrates in plasma and that binding to and/or endocytosis in red blood cells is negligible.

  1. Determination of lead, cadmium, copper, and nickel in the tonghui river of beijing, china, by cloud point extraction-high resolution continuum source graphite furnace atomic absorption spectrometry.

    Science.gov (United States)

    Ren, Ting; Zhao, Li-Jiao; Sun, Bo-Si; Zhong, Ru-Gang

    2013-11-01

    Heavy metal contamination of water has become an important problem in recent years. Most hazardous heavy metals exist in environmental water in trace or ultra-trace amounts, which requires establishing highly sensitive analytical methods. In this research, quantitative analyses were performed using high-resolution continuum source graphite furnace atomic absorption spectrometry combined with cloud point extraction (CPE) to determine Pb, Cd, Cu, and Ni levels in environmental surface water. By optimizing the CPE conditions, the enrichment factors were 29 for Pb, Cd, and Cu and 25 for Ni. The limits of detection (LOD) were 0.080, 0.010, 0.035, and 0.014 μg L for Pb, Cd, Cu, and Ni, respectively. The sensitivity of the method is comparable with those reported in previous investigations using various methods and improves outcome by 2 to 3 orders of magnitude compared with the LODs of the current national standard methods of China. Our method was used to determine Pb, Cd, Cu, and Ni in 55 water samples collected from the Tonghui River, which is the principal river in the urban area of Beijing, China. The results indicated that the distributions of the four heavy metals in the Tonghui River were related with the environments. The levels of Pb and Ni exhibit increasing trends along the river from upstream to downstream possibly due to the existence of some chemical factories in the downstream area. Lead, Cd, Cu, and Ni averaged 13.9, 0.8, 46.8, and 38.5%, respectively, of the total amount of the determined heavy metals. The levels of the four heavy metals conformed to the Environmental Quality Standards for Surface Water (Grade I) of China. This work provides a reliable quantitative method to determine trace-amount heavy metals in water, which lays a foundation for establishing standards and regulations for environmental water protection.

  2. Ultrasound-assisted single-drop microextraction for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Jorge S.; Anunciação, Taiana A. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Brandão, Geovani C. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); INCT de Energia e Ambiente, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Dantas, Alailson F. [Departamento de Química Analítica, Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, Bahia 40170-280 (Brazil); Lemos, Valfredo A. [Laboratório de Química Analítica (LQA), Universidade Estadual do Sudoeste da Bahia, Campus de Jequié, Jequié, Bahia 45506-191 (Brazil); and others

    2015-05-01

    This work presents an ultrasound-assisted single-drop microextraction procedure for the determination of cadmium in vegetable oils using high-resolution continuum source electrothermal atomic absorption spectrometry. Some initial tests showed that the best extraction efficiency was obtained when using ultrasound instead of mechanical agitation, indicating that acoustic cavitation improved the extraction process. Nitric, hydrochloric and acetic acids were evaluated for use in the extraction process, and HNO{sub 3} gave the best results. A two-level full-factorial design was applied to investigate the best conditions for the extraction of Cd from the oil samples. The influences of the sonication amplitude, time and temperature of the extraction were evaluated. The results of the design revealed that all of the variables had a significant effect on the experimental results. Afterward, a Box–Behnken design was applied to determine the optimum conditions for the determination of cadmium in vegetable oil samples. According to a multivariate study, the optimum conditions were as follows: sonication amplitude of 60%, extraction time of 15 min, extraction temperature of 46 °C and 0.1 mol L{sup −1} HNO{sub 3} as the extractor solution. Under optimized conditions, the developed method allows for the determination of Cd in oil samples with a limit of quantification of 7.0 ng kg{sup −1}. Addition and recovery experiments were performed in vegetable oil samples to evaluate the accuracy of the method, and the recoveries obtained varied from 90% to 115%. The samples were also analyzed after the acid digestion procedure, and the paired t-test (95% confidence level) did not show significant differences from the proposed method. - Highlights: • The determination of cadmium in vegetable oils was developed using UA-SDME. • HR-CS ET-AAS was employed as a detection technique with direct drop sampling. • The procedure allowed for a reduction in the consumption of reagents and

  3. Determination of Pb (Lead, Cd (Cadmium, Cr (Chromium, Cu (Copper, and Ni (Nickel in Chinese tea with high-resolution continuum source graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Wen-Si Zhong

    2016-01-01

    Full Text Available The contents of lead, cadmium, chromium, copper, and nickel were determined in 25 tea samples from China, including green, yellow, white, oolong, black, Pu'er, and jasmine tea products, using high-resolution continuum source graphite furnace atomic absorption spectrometry. The methods used for sample preparation, digestion, and quantificational analysis were established, generating satisfactory analytical precisions (represented by relative standard deviations ranging from 0.6% to 2.5% and recoveries (98.91–101.32%. The lead contents in tea leaves were 0.48–10.57 mg/kg, and 80% of these values were below the maximum values stated by the guidelines in China. The contents of cadmium and chromium ranged from 0.01 mg/kg to 0.39 mg/kg and from 0.27 mg/kg to 2.45 mg/kg, respectively, remaining in compliance with the limits stipulated by China's Ministry of Agriculture. The copper contents were 7.73–63.71 mg/kg; only 64% of these values complied with the standards stipulated by the Ministry of Agriculture. The nickel contents ranged from 2.70 mg/kg to 13.41 mg/kg. Consequently, more attention must be paid to the risks of heavy metal contamination in tea. The quantitative method established in this work lays a foundation for preventing heavy metal toxicity in human from drinking tea and will help establish regulations to control the contents of heavy metals in tea.

  4. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  5. Atomic energy

    CERN Multimedia

    1996-01-01

    Interviews following the 1991 co-operation Agreement between the Department of Atomic Energy (DAE) of the Government of India and the European Organization for Nuclear Research (CERN) concerning the participation in the Large Hadron Collider Project (LHC) . With Chidambaram, R, Chairman, Atomic Energy Commission and Secretary, Department of Atomic Energy, Department of Atomic Energy (DAE) of the Government of India and Professor Llewellyn-Smith, Christopher H, Director-General, CERN.

  6. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  7. Modeling of neutrals in the Linac4 H{sup −} ion source plasma: Hydrogen atom production density profile and H{sub α} intensity by collisional radiative model

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, T., E-mail: t.yamamoto@ppl.appi.keio.ac.jp; Shibata, T.; Ohta, M.; Yasumoto, M.; Nishida, K.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Yokohama 223-8522 (Japan); Mattei, S.; Lettry, J. [CERN, 1211 Geneva 23 (Switzerland); Sawada, K. [Faculty of Engineering, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan); Fantz, U. [Max-Plank-Instutut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

    2014-02-15

    To control the H{sup 0} atom production profile in the H{sup −} ion sources is one of the important issues for the efficient and uniform surface H{sup −} production. The purpose of this study is to construct a collisional radiative (CR) model to calculate the effective production rate of H{sup 0} atoms from H{sub 2} molecules in the model geometry of the radio-frequency (RF) H{sup −} ion source for Linac4 accelerator. In order to validate the CR model by comparison with the experimental results from the optical emission spectroscopy, it is also necessary for the model to calculate Balmer photon emission rate in the source. As a basic test of the model, the time evolutions of H{sup 0} production and the Balmer H{sub α} photon emission rate are calculated for given electron energy distribution functions in the Linac4 RF H{sup −} ion source. Reasonable test results are obtained and basis for the detailed comparisons with experimental results have been established.

  8. Accurate Atom Counting in Mesoscopic Ensembles

    CERN Document Server

    Hume, D B; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-01-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  9. Accurate Atom Counting in Mesoscopic Ensembles

    Science.gov (United States)

    Hume, D. B.; Stroescu, I.; Joos, M.; Muessel, W.; Strobel, H.; Oberthaler, M. K.

    2013-12-01

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  10. Accurate atom counting in mesoscopic ensembles.

    Science.gov (United States)

    Hume, D B; Stroescu, I; Joos, M; Muessel, W; Strobel, H; Oberthaler, M K

    2013-12-20

    Many cold atom experiments rely on precise atom number detection, especially in the context of quantum-enhanced metrology where effects at the single particle level are important. Here, we investigate the limits of atom number counting via resonant fluorescence detection for mesoscopic samples of trapped atoms. We characterize the precision of these fluorescence measurements beginning from the single-atom level up to more than one thousand. By investigating the primary noise sources, we obtain single-atom resolution for atom numbers as high as 1200. This capability is an essential prerequisite for future experiments with highly entangled states of mesoscopic atomic ensembles.

  11. Topics in atomic physics

    CERN Document Server

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

  12. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  13. Imaging an atomic beam using fluorescence

    Institute of Scientific and Technical Information of China (English)

    Ming He(何明); Jin Wang(王谨); Mingsheng Zhan(詹明生)

    2003-01-01

    A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed by a commercial CCD-camera, which is corresponding to the atomic state and velocity distribution. The detection scheme has a great utilization in the experiments of cold atoms and atomic optics.

  14. A trapped atom interferometer with ultracold Sr atoms

    CERN Document Server

    Zhang, Xian; Mazzoni, Tommaso; Poli, Nicola; Tino, Guglielmo M

    2016-01-01

    We report on a trapped atom interferometer based on Bragg diffraction and Bloch oscillations with alkaline-earth-metal atoms. We use a Ramsey-Bord\\'e Bragg interferometer with $^{88}$Sr atoms combined with Bloch oscillations to extend the interferometer time. Thanks to a long coherence time for Bloch oscillations of $^{88}$Sr atoms, we observed interference up to 1 s evolution time in the lattice. A detailed study of decoherence sources during the Bloch phase is also presented. While still limited in sensitivity by lattice lifetime and beam inhomogeneity this result opens the way to high contrast trapped interferometers with extended interrogation time.

  15. Nanoscale infrared (IR) spectroscopy and imaging of structural lipids in human stratum corneum using an atomic force microscope to directly detect absorbed light from a tunable IR laser source.

    Science.gov (United States)

    Marcott, Curtis; Lo, Michael; Kjoller, Kevin; Domanov, Yegor; Balooch, Guive; Luengo, Gustavo S

    2013-06-01

    An atomic force microscope (AFM) and a tunable infrared (IR) laser source have been combined in a single instrument (AFM-IR) capable of producing ~200-nm spatial resolution IR spectra and absorption images. This new capability enables IR spectroscopic characterization of human stratum corneum at unprecendented levels. Samples of normal and delipidized stratum corneum were embedded, cross-sectioned and mounted on ZnSe prisms. A pulsed tunable IR laser source produces thermomechanical expansion upon absorption, which is detected through excitation of contact resonance modes in the AFM cantilever. In addition to reducing the total lipid content, the delipidization process damages the stratum corneum morphological structure. The delipidized stratum corneum shows substantially less long-chain CH2 -stretching IR absorption band intensity than normal skin. AFM-IR images that compare absorbances at 2930/cm (lipid) and 3290/cm (keratin) suggest that regions of higher lipid concentration are located at the perimeter of corneocytes in the normal stratum corneum.

  16. Atomic entanglement and decoherence

    Science.gov (United States)

    Genes, Claudiu

    The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new "unravelling" is proposed, that employs the detection of photon number in a single

  17. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  18. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  19. Atomic Beam Merging and Suppression of Alkali Contaminants in Multi Body High Power Targets: Design and Test of Target and Ion Source Prototypes at ISOLDE

    CERN Document Server

    Bouquerel, Elian J A; Lettry, J; Stora, T

    2009-01-01

    The next generation of high power ISOL-facilities will deliver intense and pure radioactive ion beams. Two key issues of developments mandatory for the forthcoming generation of ISOL target-ion source units are assessed and demonstrated in this thesis. The design and production of target and ion-source prototypes is described and dedicated measurements at ISOLDE-CERN of their radioisotope yields are analyzed. The purity of short lived or rare radioisotopes suffer from isobaric contaminants, notably alkalis which are highly volatile and easily ionized elements. Therefore, relying on their chemical nature, temperature controlled transfer lines were equipped with a tube of quartz that aimed at trapping these unwanted elements before they reached the ion source. The successful application yields high alkali-suppression factors for several elements (ie: 80, 82mRb, 126, 142Cs, 8Li, 46K, 25Na, 114In, 77Ga, 95, 96Sr) for quartz temperatures between 300ºC and 1100ºC. The enthalpies of adsorption on quartz were measu...

  20. An electrostatic ion pump with nanostructured Si field emission electron source and Ti particle collectors for supporting an ultra-high vacuum in miniaturized atom interferometry systems

    Science.gov (United States)

    Basu, Anirban; Velásquez-García, Luis F.

    2016-12-01

    We report a field emission-based, magnetic-less ion pump architecture for helping maintain a high vacuum within a small chamber that is compatible with miniaturized cold-atom interferometry systems. A nanostructured silicon field emitter array, with each nano-sharp tip surrounded by a self-aligned proximal gate electrode, is used to generate a surplus of electrons that cause impact ionization of gas molecules. A two-stage cylindrical electron collector, made of titanium, is used to increase the travel distance of the electrons, augmenting the ionization probability; gas ionization is subsequently followed by gettering of the ions by a negatively charged, annular-shaped titanium electrode. A proof-of-concept pump prototype was characterized using a 25 cm3 stainless steel vacuum chamber backed up by an external turbomolecular pump, a diaphragm pump, and a standard ion pump. Pumping action was observed with the electrostatic pump operating alone after an initial rapid rise of the chamber pressure due to electron/ion scrubbing. In addition, running the electrostatic pump in combination with the standard ion pump results in a lower vacuum level compared to the vacuum level produced by the standard ion pump acting alone. A proposed reduced-order model accurately predicts the functional dependence of the pressure versus time data and provides a good estimate of the characteristic pumping time constant inferred from the experiments.

  1. Design, fabrication and performance evaluation of a 22-channel direct reading atomic emission spectrometer using inductively coupled plasma as a source of excitation

    Indian Academy of Sciences (India)

    R P Shukla; S S Bhattacharya; D V Udupa; T Jayasekharan; P P Khanna; S M Marathe; Sampath Kumar; M N Patil; S V G Ravindranath; Sandeep Guha; M B Guhagarkar; A P Roy

    2000-02-01

    The indigenous design, fabrication and performance evaluation of a polychromator, using inductively coupled plasma (ICP) as a source of excitation, are described. A concave holographic grating is used asthe dispersing element and a Paschen-Runge mount is chosen to focus the spectra over a wide range along the Rowland circle. Twenty-two exitslits, mounted along the circle, precisely correspond to the wavelengths used for determination of up to twenty elements present in the plasma. Radiations emerging from the exit slits are detected by photomultiplier tubes placed behind them. The photomultipliersignal isrecorded by an electronic system consisting of an integrator and a PC-based data acquisition system. The performance of the spectrometer has been evaluated with an ICP excitation source. Synthetic standards in deionized water containing a mixture of twenty impurities have been analysed. Typical determination limits observed for elements range from sub-ppm to ppm levels. All the elements present as impurities can be detected simultaneously. It is also observed that each element has a different emitting region in the ICP flame for which the maximum signal to the background is obtained. The determination limits obtained corresponding to these zones are the lowest. A study of the sensitive emitting zones for several elements has been carried out and the results are demonstrated by photographs of the ICP flame. The study will help in achieving the minimum value of determination limitfor an impurity element.

  2. Programmable atom-photon quantum interface

    Science.gov (United States)

    Kurz, Christoph; Eich, Pascal; Schug, Michael; Müller, Philipp; Eschner, Jürgen

    2016-06-01

    We present the implementation of a programmable atom-photon quantum interface, employing a single trapped +40Ca ion and single photons. Depending on its mode of operation, the interface serves as a bidirectional atom-photon quantum-state converter, as a source of entangled atom-photon states, or as a quantum frequency converter of single photons. The interface lends itself particularly to interfacing ions with spontaneous parametric down-conversion-based single-photon or entangled-photon-pair sources.

  3. Evaluation of two-stage system for neutron measurement aiming at increase in count rate at Japan Atomic Energy Agency-Fusion Neutronics Source

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, K., E-mail: shinohara.koji@jaea.go.jp; Ochiai, K.; Sukegawa, A. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Ishii, K.; Kitajima, S. [Department of Quantum Science and Energy Engineering, Tohoku University, Sendai, Miyagi 980-8579 (Japan); Baba, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Sasao, M. [Organization for Research Initiatives and Development, Doshisha University, Kyoto 602-8580 (Japan)

    2014-11-15

    In order to increase the count rate capability of a neutron detection system as a whole, we propose a multi-stage neutron detection system. Experiments to test the effectiveness of this concept were carried out on Fusion Neutronics Source. Comparing four configurations of alignment, it was found that the influence of an anterior stage on a posterior stage was negligible for the pulse height distribution. The two-stage system using 25 mm thickness scintillator was about 1.65 times the count rate capability of a single detector system for d-D neutrons and was about 1.8 times the count rate capability for d-T neutrons. The results suggested that the concept of a multi-stage detection system will work in practice.

  4. The effect of oxygen source on atomic layer deposited Al{sub 2}O{sub 3} as blocking oxide in metal/aluminum oxide/nitride/oxide/silicon memory capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaou, Nikolaos, E-mail: n.nikolaou@imel.demokritos.gr [Department of Microelectronics, NCSR “Demokritos”, 153 10 Athens (Greece); Department of Physics, University of Patras, 265 04 Patras (Greece); Ioannou-Sougleridis, Vassilios; Dimitrakis, Panagiotis; Normand, Pascal [Department of Microelectronics, NCSR “Demokritos”, 153 10 Athens (Greece); Skarlatos, Dimitrios [Department of Physics, University of Patras, 265 04 Patras (Greece); Giannakopoulos, Konstantinos [Department of Microelectronics, NCSR “Demokritos”, 153 10 Athens (Greece); Kukli, Kaupo [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland); Institute of Physics, University of Tartu, Riia 142, EE-51014 Tartu (Estonia); Niinistö, Jaakko; Ritala, Mikko; Leskelä, Markku [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland)

    2013-04-30

    This work explores the electrical properties of Al{sub 2}O{sub 3} films formed by atomic layer deposition (ALD) using different oxygen sources (water and ozone) and trimethylaluminium (TMA). The as-deposited Al{sub 2}O{sub 3} layers were used as blocking oxides in metal (Pt)–alumina–nitride–oxide–silicon memory capacitors. The capacitance–voltage characteristics of the devices with Al{sub 2}O{sub 3} deposited with the ozone–TMA and water–TMA processes showed almost identical capacitance equivalent thicknesses in accordance with transmission electron microscopy imaging which revealed similar dielectric layer thicknesses between the two gate stacks. At high negative gate voltages the water-TMA devices exhibited higher leakage currents than the ozone-TMA devices. This effect had a direct impact on the attainable memory window, due to the limited erase performance of the capacitors and the extended erase-saturation effect. These findings indicate that the ALD chemistry and in particular the oxygen source is a crucial factor which determines the electrical behavior of the as-deposited Al{sub 2}O{sub 3} films, and therefore the performance of the memory stacks. These differences are attributed to the different trap distributions either in space or energy within the Al{sub 2}O{sub 3} layers. - Highlights: ► Al{sub 2}O{sub 3} films were formed by atomic layer deposition using H{sub 2}O and O{sub 3} as oxygen sources. ► Al{sub 2}O{sub 3} layers were used as blocking oxides in charge trapping memory capacitors. ► At high negative voltages, H{sub 2}O-based samples exhibit higher leakage current density. ► The H{sub 2}O-based samples have a limited ability to remove trapped electrons. ► Oxygen source differentiates the electrical behavior of as-deposited Al{sub 2}O{sub 3} layers.

  5. Precision Control of Cold Rubidium Atoms

    Science.gov (United States)

    Nic Chormaic, Síle; Deasy, Kieran; Morrissey, Michael; Shortt, Brian; Yarovitskiy, Alexander

    2005-10-01

    Research interest in designing sources of cold atoms has significantly increased during the past 10 years with the development of suitable laser sources for magneto-optical trapping and the further mastering of evaporative cooling in order to achieve Bose-Einstein condensation. The magneto-optical trap is now viewed as a standard research facility worldwide and has opened up many exciting research directions in atomic physics. One area of interest is that of combining spherical microcavities with cold atomic sources in order to achieve efficient photon exchange between the cavity and atom for further understandings of cavity quantum electrodynamics. This could eventually lead to atom entanglement via photon exchange, which would have implications for quantum logic design. However, initial attempts to achieve such interactions have been hindered by inadequate control and manipulation of the cold atom source. Here, we present work on designing and building an ultra-stable source of magneto-optically cooled rubidium atoms with a temperature in the tens of μK range. We present a suitable experimental arrangement including details on the ultra-high vacuum chamber, the laser systems being used, and the source of rubidium vapor. We discuss some future directions for the research, including diffraction of atoms from gratings and micron-sized objects and parameter control of the atom cloud.

  6. Atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, A.E.; Kukla, K.; Cheng, S. [Univ. of Toledo, OH (United States)] [and others

    1995-08-01

    In a collaboration with the Atomic Physics group at Argonne and the University of Toledo, the Atomic Physics group at the University of Notre Dame is measuring the fine structure transition energies in highly-charged lithium-like and helium-like ions using beam-foil spectroscopy. Precise measurements of 2s-2p transition energies in simple (few-electron) atomic systems provide stringent tests of several classes of current atomic- structure calculations. Analyses of measurements in helium-like Ar{sup 16+} have been completed, and the results submitted for publication. A current goal is to measure the 1s2s{sup 3}S{sub 1} - 1s2p{sup 3}P{sub 0} transition wavelength in helium-like Ni{sup 26+}. Measurements of the 1s2s{sup 2}S{sub 1/2} - 1s2p{sup 2}P{sub 1/2,3/2} transition wavelengths in lithium-like Kr{sup 33+} is planned. Wavelength and lifetime measurements in copper-like U{sup 63+} are also expected to be initiated. The group is also participating in measurements of forbidden transitions in helium-like ions. A measurement of the lifetime of the 1s2s{sup 3}S{sub 1} state in Kr{sup 34+} was published recently. In a collaboration including P. Mokler of GSI, Darmstadt, measurements have been made of the spectral distribution of the 2E1 decay continuum in helium-like Kr{sup 34+}. Initial results have been reported and further measurements are planned.

  7. The Atomic orbitals of the topological atom

    OpenAIRE

    Ramos-Cordoba, Eloy; Salvador Sedano, Pedro

    2013-01-01

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These c...

  8. Exotic atoms and their electron shell

    Energy Technology Data Exchange (ETDEWEB)

    Simons, L.M.; Abbot, D.; Bach, B.; Bacher, R.; Badertscher, A.; Bluem, P.; DeCecco, P.; Eades, J.; Egger, J.; Elsener, K.; Gotta, D.; Hauser, P.; Heitlinger, K.; Horvath, D.; Kottmann, F.; Morenzoni, E.; Missimer, J.; Reidy, J.J.; Siegel, R.; Taqqu, D.; Viel, D. (Paul Scherrer Inst., Villigen (Switzerland) Coll. of William and Mary, Williamsburg, VA (United States) Kernforschungszentrum Karlsruhe GmbH, Inst. fuer Kernphysik, Karlsruhe (Germany) Inst. fuer Experimentelle Kernphysik, Univ. Karlsruhe (Germany) CERN, Geneva (Switzerland) Forschungszentrum Juelich GmbH, Inst. fuer Kernphysik (Germany) KFKI Research Inst. for Particle and Nuclear Physics, Budapest (Hungary) Univ. Pisa (Italy) INFN - Pisa (Italy) ETH Zuerich, Villigen (Switzerland) Physics Dept., Univ. of Mississippi, University, MS (United States))

    1994-04-01

    Progress in the field of exotic atoms seems to increase proportionally with the number of exotic atoms produced and the increase in energy resolution with which the transition energies are determined. Modern experiments use high resolution crystal spectrometers or even aim at laser spectroscopy. The accuracy of these methods is limited by the interaction of the exotic atoms with their surroundings. The most important source of errors is the energy shift caused by the not well known status of the atomic electron shell. A novel method to eliminate these sources of error is presented and the possibilities for further high precision experiments is outlined. (orig.)

  9. Exotic atoms and their electron shell

    Science.gov (United States)

    Simons, L. M.; Abbot, D.; Bach, B.; Bacher, R.; Badertscher, A.; Blüm, P.; DeCecco, P.; Eades, J.; Egger, J.; Elsener, K.; Gotta, D.; Hauser, P.; Heitlinger, K.; Horváth, D.; Kottmann, F.; Morenzoni, E.; Missimer, J.; Reidy, J. J.; Siegel, R.; Taqqu, D.; Viel, D.

    1994-04-01

    Progress in the field of exotic atoms seems to increase proportionally with the number of exotic atoms produced and the increase in energy resolution with which the transition energies are determined. Modern experiments use high resolution crystal spectrometers or even aim at laser spectroscopy. The accuracy of these methods is limited by the interaction of the exotic atoms with their surroundings. The most important source of errors is the energy shift caused by the not well known status of the atomic electron shell. A novel method to eliminate these sources of error is presented and the possibilities for further high precision experiments is outlined.

  10. High-altitude atomic nitrogen densities

    Science.gov (United States)

    Oran, E. S.; Strobel, D. F.; Mauersberger, K.

    1978-01-01

    Theoretical calculations of the seasonal and diurnal variations of atomic nitrogen are compared with measurements made by the open source neutral mass spectrometer on the AE-C satellite. With the simultaneous measurements of molecular nitrogen and atomic oxygen densities as input, model calculations of odd nitrogen densities predict the same trends in atomic nitrogen as those observed. From these comparisons it is inferred that horizontal transport significantly reduces the diurnal variation of atomic nitrogen. Estimates are given of the sensitivity of atomic nitrogen densities to variations in the photoelectron flux, the neutral temperatures, and the neutral winds.

  11. Atomic magnetometer

    Science.gov (United States)

    Schwindt, Peter [Albuquerque, NM; Johnson, Cort N [Albuquerque, NM

    2012-07-03

    An atomic magnetometer is disclosed which uses a pump light beam at a D1 or D2 transition of an alkali metal vapor to magnetically polarize the vapor in a heated cell, and a probe light beam at a different D2 or D1 transition to sense the magnetic field via a polarization rotation of the probe light beam. The pump and probe light beams are both directed along substantially the same optical path through an optical waveplate and through the heated cell to an optical filter which blocks the pump light beam while transmitting the probe light beam to one or more photodetectors which generate electrical signals to sense the magnetic field. The optical waveplate functions as a quarter waveplate to circularly polarize the pump light beam, and as a half waveplate to maintain the probe light beam linearly polarized.

  12. High Atom Number in Microsized Atom Traps

    Science.gov (United States)

    2015-12-14

    Final Performance Report on ONR Grant N00014-12-1-0608 High atom number in microsized atom traps for the period 15 May 2012 through 14 September...TYPE Final Technical Report 3. DATES COVERED (From - To) 05/15/2012-09/14/2012 4. TITLE AND SUBTITLE High atom number in microsized atom traps...forces for implementing a small-footprint, large-number atom -chip instrument. Bichromatic forces rely on absorption and stimulated emission to produce

  13. Understanding the mechanisms of interfacial reactions during TiO2 layer growth on RuO2 by atomic layer deposition with O2 plasma or H2O as oxygen source

    Science.gov (United States)

    Chaker, A.; Szkutnik, P. D.; Pointet, J.; Gonon, P.; Vallée, C.; Bsiesy, A.

    2016-08-01

    In this paper, TiO2 layers grown on RuO2 by atomic layer deposition (ALD) using tetrakis (dimethyla-mino) titanium (TDMAT) and either oxygen plasma or H2O as oxygen source were analyzed using X-ray diffraction (XRD), Raman spectroscopy, and depth-resolved X-ray Photoelectron spectroscopy (XPS). The main objective is to investigate the surface chemical reactions mechanisms and their influence on the TiO2 film properties. The experimental results using XRD show that ALD deposition using H2O leads to anatase TiO2 whereas a rutile TiO2 is obtained when oxygen-plasma is used as oxygen source. Depth-resolved XPS analysis allows to determine the reaction mechanisms at the RuO2 substrate surface after growth of thin TiO2 layers. Indeed, the XPS analysis shows that when H2O assisted ALD process is used, intermediate Ti2O3 layer is obtained and RuO2 is reduced into Ru as evidenced by high resolution transmission electron microscopy. In this case, there is no possibility to re-oxidize the Ru surface into RuO2 due to the weak oxidation character of H2O and an anatase TiO2 layer is therefore grown on Ti2O3. In contrast, when oxygen plasma is used in the ALD process, its strong oxidation character leads to the re-oxidation of the partially reduced RuO2 following the first Ti deposition step. Consequently, the RuO2 surface is regenerated, allowing the growth of rutile TiO2. A surface chemical reaction scheme is proposed that well accounts for the observed experimental results.

  14. High-energy atomic physics

    CERN Document Server

    Drukarev, Evgeny G

    2016-01-01

    This self-contained text introduces readers to the field of high-energy atomic physics - a new regime of photon-atom interactions in which the photon energies significantly exceed the atomic or molecular binding energies, and which opened up with the recent advent of new synchrotron sources. From a theoretical point of view, a small-parameter characteristic of the bound system emerged, making it possible to perform analytic perturbative calculations that can in turn serve as benchmarks for more powerful numerical computations. The first part of the book introduces readers to the foundations of this new regime and its theoretical treatment. In particular, the validity of the small-parameter perturbation expansion and of the lowest-order approximation is critically reviewed. The following chapters then apply these insights to various atomic processes, such as photoionization as a many-body problem, dominant mechanisms for the production of ions at higher energies, Compton scattering and ionization accompanied b...

  15. Investigation of systematic errors of metastable "atomic pair" number

    CERN Document Server

    Yazkov, V

    2015-01-01

    Sources of systematic errors in analysis of data, collected in 2012, are analysed. Esti- mations of systematic errors in a number of “atomic pairs” fr om metastable π + π − atoms are presented.

  16. Advanced Light Source (ALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Light Source (ALS), a world leader in soft x-ray science, generates light in the wavelengths needed for examining the atomic and electronic structure of...

  17. Theoretical Calculations of Atomic Data for Spectroscopy

    Science.gov (United States)

    Bautista, Manuel A.

    2000-01-01

    Several different approximations and techniques have been developed for the calculation of atomic structure, ionization, and excitation of atoms and ions. These techniques have been used to compute large amounts of spectroscopic data of various levels of accuracy. This paper presents a review of these theoretical methods to help non-experts in atomic physics to better understand the qualities and limitations of various data sources and assess how reliable are spectral models based on those data.

  18. The atomic orbitals of the topological atom.

    Science.gov (United States)

    Ramos-Cordoba, Eloy; Salvador, Pedro; Mayer, István

    2013-06-07

    The effective atomic orbitals have been realized in the framework of Bader's atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure.

  19. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  20. Conduction of molecular electronic devices: Qualitative insights through atom-atom polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Stuyver, T.; Fias, S., E-mail: sfias@vub.ac.be; De Proft, F.; Geerlings, P. [ALGC, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussel (Belgium); Fowler, P. W. [Department of Chemistry, University of Sheffield, Sheffield S3 7HF (United Kingdom)

    2015-03-07

    The atom-atom polarizability and the transmission probability at the Fermi level, as obtained through the source-and-sink-potential method for every possible configuration of contacts simultaneously, are compared for polycyclic aromatic compounds. This comparison leads to the conjecture that a positive atom-atom polarizability is a necessary condition for transmission to take place in alternant hydrocarbons without non-bonding orbitals and that the relative transmission probability for different configurations of the contacts can be predicted by analyzing the corresponding atom-atom polarizability. A theoretical link between the two considered properties is derived, leading to a mathematical explanation for the observed trends for transmission based on the atom-atom polarizability.

  1. Conduction of molecular electronic devices: qualitative insights through atom-atom polarizabilities.

    Science.gov (United States)

    Stuyver, T; Fias, S; De Proft, F; Fowler, P W; Geerlings, P

    2015-03-07

    The atom-atom polarizability and the transmission probability at the Fermi level, as obtained through the source-and-sink-potential method for every possible configuration of contacts simultaneously, are compared for polycyclic aromatic compounds. This comparison leads to the conjecture that a positive atom-atom polarizability is a necessary condition for transmission to take place in alternant hydrocarbons without non-bonding orbitals and that the relative transmission probability for different configurations of the contacts can be predicted by analyzing the corresponding atom-atom polarizability. A theoretical link between the two considered properties is derived, leading to a mathematical explanation for the observed trends for transmission based on the atom-atom polarizability.

  2. Trace elements determination in high salinity petroleum produced formation water by high-resolution continuum source graphite furnace atomic absorption spectrometry after matrix separation using Chelex-100 Registered-Sign resin

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Aline Soares [Departamento de Geoquimica, Universidade Federal Fluminense, Outeiro Sao Joao Batista s/n, Centro, Niteroi/RJ, 24020-150 (Brazil); Departamento de Quimica Analitica, Universidade Federal do Rio de Janeiro Av. Athos da Silveira Ramos 149, Centro de Tecnologia, Bloco A, Cidade Universitaria, Rio de Janeiro/RJ, 21941-909 (Brazil); Santelli, Ricardo Erthal, E-mail: santelli@iq.ufrj.br [Departamento de Geoquimica, Universidade Federal Fluminense, Outeiro Sao Joao Batista s/n, Centro, Niteroi/RJ, 24020-150 (Brazil); Departamento de Quimica Analitica, Universidade Federal do Rio de Janeiro Av. Athos da Silveira Ramos 149, Centro de Tecnologia, Bloco A, Cidade Universitaria, Rio de Janeiro/RJ, 21941-909 (Brazil)

    2012-05-15

    This study describes a procedure used for the determination of trace metals (Co, Cu, Mn, Ni and Pb) in high salinity petroleum produced formation water (PFW) employing high-resolution continuum source graphite furnace atomic absorption spectrometry for detection and Chelex-100 Registered-Sign resin for matrix elimination and analytes preconcentration. Using 15.0 mL of PFW for the separation/preconcentration, detection limits of 0.006, 0.07, 0.03, 0.08 and 0.02 {mu}g L{sup -1} were obtained for Co, Cu, Mn, Ni and Pb, respectively. The accuracy of the proposed method was evaluated by analyzing three seawater certified reference materials and by recovery tests, and the data indicate that the methodology can be successfully applied to this kind of samples. The precision values, expressed as relative standard deviation (% RSD, n = 10) for 2.0 {mu}g L{sup -1}, were found to be 3.5, 4.0, 9.0, 5.3 and 5.9 for Co, Cu, Mn, Ni and Pb, respectively. The proposed procedure was applied for the determination of these metals in medium and high salinity PFW samples obtained from Brazilian offshore petroleum exploration platforms. - Highlights: Black-Right-Pointing-Pointer Petroleum-produced formation water were analyzed for Co, Cu, Mn, Ni and Pb determination. Black-Right-Pointing-Pointer In batch analyte preconcentration/matrix separation using Chelex-100 Registered-Sign was used. Black-Right-Pointing-Pointer Detection limits between 0.006 and 0.08 {mu}g L{sup -1} were found by using HR-CS-GFAAS. Black-Right-Pointing-Pointer Trace elements characterization is possible using the developed method. Black-Right-Pointing-Pointer Maximum trace element concentrations found could support future Brazilian directives.

  3. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  4. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  5. Isolating and moving single atoms using silicon nanocrystals

    Science.gov (United States)

    Carroll, Malcolm S.

    2010-09-07

    A method is disclosed for isolating single atoms of an atomic species of interest by locating the atoms within silicon nanocrystals. This can be done by implanting, on the average, a single atom of the atomic species of interest into each nanocrystal, and then measuring an electrical charge distribution on the nanocrystals with scanning capacitance microscopy (SCM) or electrostatic force microscopy (EFM) to identify and select those nanocrystals having exactly one atom of the atomic species of interest therein. The nanocrystals with the single atom of the atomic species of interest therein can be sorted and moved using an atomic force microscope (AFM) tip. The method is useful for forming nanoscale electronic and optical devices including quantum computers and single-photon light sources.

  6. Classical simulation of atomic beam focusing and deposition for atom lithography

    Institute of Scientific and Technical Information of China (English)

    Xianzhong Chen(陈献忠); Hanmin Yao(姚汉民); Xunan Chen(陈旭南)

    2004-01-01

    We start from the intensity distribution of a standing wave (SW) laser field and deduce the classical equation of atomic motion. The image distortion is analyzed using transfer function approach. Atomic flux density distribution as a function of propagation distance is calculated based on Monte-Carlo scheme and trajectory tracing method. Simulation results have shown that source imperfection, especially beam spread, plays an important role in broadening the feature width, and the focus depth of atom lens for real atomic source is longer than that for perfect source. The ideal focal plane can be easily determined by the variation of atomic density at the minimal potential of the laser field as a function of traveling distance.

  7. Realisation of a Frequency Standard Using an Atomic Fountain

    CERN Document Server

    Michaud, A; Zetie, K P; Cooper, C J; Hillenbrand, G; Lorent, V; Steane, A; Foot, C J

    2005-01-01

    We report the realisation and preliminary study of a frequency standard using a fountain of laser cooled caesium atoms. Our apparatus uses a magneto-optical trap as a source of cold atoms and optical pumping to prepare the atoms in the correct state before they enter the microwave cavity.

  8. Determination of palladium, platinum and rhodium in used automobile catalysts and active pharmaceutical ingredients using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

    Energy Technology Data Exchange (ETDEWEB)

    Resano, Martín, E-mail: mresano@unizar.es [Department of Analytical Chemistry, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Flórez, María del Rosario [Department of Analytical Chemistry, Aragón Institute of Engineering Research (I3A), University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Queralt, Ignasi [Institute of Earth Sciences Jaume Almera ICTJA-CSIC, Sole Sabarís s/n, 08028 Barcelona (Spain); Marguí, Eva [Department of Chemistry, Faculty of Sciences, Universitat de Girona, Campus Montilivi s/n, 17071 Girona (Spain)

    2015-03-01

    This work investigates the potential of high-resolution continuum source graphite furnace atomic absorption spectrometry for the direct determination of Pd, Pt and Rh in two samples of very different nature. While analysis of active pharmaceutical ingredients is straightforward and it is feasible to minimize matrix effects, to the point that calibration can be carried out against aqueous standard solutions, the analysis of used automobile catalysts is more challenging requiring the addition of a chemical modifier (NH{sub 4}F·HF) to help in releasing the analytes, a more vigorous temperature program and the use of a solid standard (CRM ERM®-EB504) for calibration. However, in both cases it was possible to obtain accurate results and precision values typically better than 10% RSD in a fast and simple way, while only two determinations are needed for the three analytes, since Pt and Rh can be simultaneously monitored in both types of samples. Overall, the methods proposed seem suited for the determination of these analytes in such types of samples, offering a greener and faster alternative that circumvents the traditional problems associated with sample digestion, requiring a small amount of sample only (0.05 mg per replicate for catalysts, and a few milligrams for the pharmaceuticals) and providing sufficient sensitivity to easily comply with regulations. The LODs achieved were 6.5 μg g{sup −1} (Pd), 8.3 μg g{sup −1} (Pt) and 9.3 μg g{sup −1} (Rh) for catalysts, which decreased to 0.08 μg g{sup −1} (Pd), 0.15 μg g{sup −1} (Pt) and 0.10 μg g{sup −1} (Rh) for pharmaceuticals. - Highlights: • Solid sampling HR CS GFAAS permits the fast and direct determination of Pd, Pt and Rh. • 2 determinations suffice for the 3 elements (2 of them can be measured simultaneously). • Samples as different as car catalysts and pharmaceuticals can be accurately analyzed. • Aqueous standards (pharmaceuticals) or a solid CRM (catalysts) is used for calibration.

  9. Atom Lithography with a Chromium Atomic Beam

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-Tao; LI Tong-Bao

    2006-01-01

    @@ Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. We design an experiment setup to fabricate chromium nanolines by depositing an atomic beam of 52 Cr through an off-resonant laser standing wave with the wavelength of 425.55 nm onto a silicon substrate. The resulting nanolines exhibit a period of 215 ± 3 nm with height of 1 nm.

  10. Atomic Batteries: Energy from Radioactivity

    OpenAIRE

    Kumar, Suhas

    2015-01-01

    With alternate, sustainable, natural sources of energy being sought after, there is new interest in energy from radioactivity, including natural and waste radioactive materials. A study of various atomic batteries is presented with perspectives of development and comparisons of performance parameters and cost. We discuss radioisotope thermal generators, indirect conversion batteries, direct conversion batteries, and direct charge batteries. We qualitatively describe their principles of operat...

  11. Effusive Atomic Oven Nozzle Design Using a Microcapillary Array

    CERN Document Server

    Senaratne, Ruwan; Geiger, Zachary A; Fujiwara, Kurt M; Lebedev, Vyacheslav; Weld, David M

    2014-01-01

    We present a simple and inexpensive design for a multichannel effusive oven nozzle which provides improved atomic beam collimation and thus extended oven lifetimes. Using this design we demonstrate an atomic lithium source suitable for trapped-atom experiments. At a nozzle temperature of 525$^{\\circ}$C the total atomic beam flux directly after the nozzle is $1.2 \\times 10^{14}$ atoms per second with a peak beam intensity greater than $5.0 \\times 10^{16}$ atoms per second per steradian. This suggests an oven lifetime of several centuries of continuous operation.

  12. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  13. Comparison of trimethylgallium and triethylgallium as “Ga” source materials for the growth of ultrathin GaN films on Si (100) substrates via hollow-cathode plasma-assisted atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Alevli, Mustafa, E-mail: mustafaalevli@marmara.edu.tr [Department of Physics, Marmara University, Göztepe Kadıköy, 34722 İstanbul (Turkey); Haider, Ali; Kizir, Seda; Leghari, Shahid A.; Biyikli, Necmi, E-mail: biyikli@unam.bilkent.edu.tr [Institute of Materials Science and Nanotechnology, Bilkent University, Bilkent, 06800 Ankara, Turkey and National Nanotechnology Research Center (UNAM), Bilkent University, Bilkent, 06800 Ankara (Turkey)

    2016-01-15

    GaN films grown by hollow cathode plasma-assisted atomic layer deposition using trimethylgallium (TMG) and triethylgallium (TEG) as gallium precursors are compared. Optimized and saturated TMG/TEG pulse widths were used in order to study the effect of group-III precursors. The films were characterized by grazing incidence x-ray diffraction, atomic force microscopy, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry. Refractive index follows the same trend of crystalline quality, mean grain, and crystallite sizes. GaN layers grown using TMG precursor exhibited improved structural and optical properties when compared to GaN films grown with TEG precursor.

  14. Presenting the Bohr Atom.

    Science.gov (United States)

    Haendler, Blanca L.

    1982-01-01

    Discusses the importance of teaching the Bohr atom at both freshman and advanced levels. Focuses on the development of Bohr's ideas, derivation of the energies of the stationary states, and the Bohr atom in the chemistry curriculum. (SK)

  15. Atomic Storage States

    Institute of Scientific and Technical Information of China (English)

    汪凯戈; 朱诗尧

    2002-01-01

    We present a complete description of atomic storage states which may appear in the electromagnetically induced transparency (EIT). The result shows that the spatial coherence has been included in the atomic collective operators and the atomic storage states. In some limits, a set of multimode atomic storage states has been established in correspondence with the multimode Fock states of the electromagnetic field. This gives a better understanding of the fact that, in BIT, the optical coherent information can be preserved and recovered.

  16. Single Atom Plasmonic Switch

    OpenAIRE

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individ...

  17. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P.; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C.; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  18. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  19. Atomic Bremsstrahlung: retrospectives, current status and perspectives

    OpenAIRE

    Amusia, M. Ya.

    2005-01-01

    We describe here the Atomic bremsstrahlung - emission of continuous spectrum electromagnetic radiation, which is generated in collisions of particles that have internal deformable structure that includes positively and negatively charged constituents. The deformation of one of or both colliding partners induces multiple, mainly dipole, time-dependent electrical moments that become a source of radiation. The history of Atomic bremsstrahlung invention is presented and it's unusual in comparison...

  20. Atom column indexing: atomic resolution image analysis through a matrix representation.

    Science.gov (United States)

    Sang, Xiahan; Oni, Adedapo A; LeBeau, James M

    2014-12-01

    Here, we report the development of an approach to map atomic resolution images into a convenient matrix representation. Through the combination of two-dimensional Gaussian fitting and the projective standard deviation, atom column locations are projected onto two noncollinear reference lattice vectors that are used to assign each a unique (i, j) matrix index. By doing so, straightforward atomic resolution image analysis becomes possible. Using practical examples, we demonstrate that the matrix representation greatly simplifies categorizing atom columns to different sublattices. This enables a myriad of direct analyses, such as mapping atom column properties and correlating long-range atom column pairs. MATLAB source code can be downloaded from https://github.com/subangstrom/aci.

  1. 1982 bibliography of atomic and molecular processes

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Gregory, D.C.; Kirkpatrick, M.I.; McDaniel, E.W.; McKnight, R.H.; Meyer, F.W.; Morgan, T.J.; Phaneuf, R.A. (comps.)

    1984-05-01

    This annotated bibliography includes papers on atomic and molecular processes published during 1982. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  2. 1984 Bibliography of atomic and molecular processes

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howard, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

    1985-04-01

    This annotated bibliography includes papers on atomic and molecular processes published during 1984. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  3. 1985 bibliography of atomic and molecular processes

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, C.F.; Gilbody, H.B.; Gregory, D.C.; Griffin, P.M.; Havener, C.C.; Howald, A.M.; Kirkpatrick, M.I.; McDaniel, E.W.; Meyer, F.W.; Morgan, T.J. (comps.)

    1986-06-01

    This annotated bibliography includes papers on atomic and molecular processes published during 1985. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  4. Bibliography of atomic and molecular processes, 1983

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, C.F.; Crandall, D.H.; Gilbody, H.B.; Gregory, D.C.; Kirkpatrick, M.I.; McDaniel, E.W.; McKnight, R.H.; Meyer, F.W.; Morgan, T.J.; Phaneuf, R.A. (comps.)

    1984-10-01

    This annotated bibliography includes papers on atomic and molecular processes published during 1983. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing, the entries are indexed according to the categories and according to reactants within each subcategory.

  5. Double Photoionization of Atomic Oxygen

    Science.gov (United States)

    Wickramarathna, Madhushani; Gorczyca, Thomas; Ballance, Connor; Stolte, Wayne

    2016-05-01

    Double photoionization of atomic oxygen was first measured at Aladdin, a second-generation synchrotron source, at lower resolution (Angel and Samson, PRA, 38, 5573, 1988). Here we present new experimental and theoretical results for the direct double photoionization of atomic oxygen. The experiment was performed at the Advanced Light Source for photon energies near the double-ionization threshold, revealing rich resonance structures converging to multiple single-ionization thresholds. State-of-the-art calculations were performed using the R-matrix with pseudostates (RMPS) method (P. G. Burke, R-matrix Theory of Atomic Collisions, Springer 2011) as implemented by Gorczya and Badnell (JPB, 30, 3897, 1997), and recently applied, in a converged representation, to the double photoionization of helium (T. W. Gorczyca et al., JPB, 46, 195201, 2013). The much-larger calculation required for oxygen, due to the many target state symmetries compared to helium, necessitated a parallel RMPS approach. Comparison between theoretical and experimental results shows overall qualitative agreement but also some puzzling discrepancies: experimental features that are not reproduced by the RMPS calculations.

  6. Atomic switches: atomic-movement-controlled nanodevices for new types of computing

    Directory of Open Access Journals (Sweden)

    Takami Hino, Tsuyoshi Hasegawa, Kazuya Terabe, Tohru Tsuruoka, Alpana Nayak, Takeo Ohno and Masakazu Aono

    2011-01-01

    Full Text Available Atomic switches are nanoionic devices that control the diffusion of metal cations and their reduction/oxidation processes in the switching operation to form/annihilate a metal atomic bridge, which is a conductive path between two electrodes in the on-state. In contrast to conventional semiconductor devices, atomic switches can provide a highly conductive channel even if their size is of nanometer order. In addition to their small size and low on-resistance, their nonvolatility has enabled the development of new types of programmable devices, which may achieve all the required functions on a single chip. Three-terminal atomic switches have also been developed, in which the formation and annihilation of a metal atomic bridge between a source electrode and a drain electrode are controlled by a third (gate electrode. Three-terminal atomic switches are expected to enhance the development of new types of logic circuits, such as nonvolatile logic. The recent development of atomic switches that use a metal oxide as the ionic conductive material has enabled the integration of atomic switches with complementary metal-oxide-semiconductor (CMOS devices, which will facilitate the commercialization of atomic switches. The novel characteristics of atomic switches, such as their learning and photosensing abilities, are also introduced in the latter part of this review.

  7. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  8. Cold-atom Inertial Sensor without Deadtime

    CERN Document Server

    Fang, Bess; Savoie, Denis; Venon, Bertrand; Alzar, Carlos L Garrido; Geiger, Remi; Landragin, Arnaud

    2016-01-01

    We report the operation of a cold-atom inertial sensor in a joint interrogation scheme, where we simultaneously prepare a cold-atom source and operate an atom interferometer in order to eliminate dead times. Noise aliasing and dead times are consequences of the sequential operation which is intrinsic to cold-atom atom interferometers. Both phenomena have deleterious effects on the performance of these sensors. We show that our continuous operation improves the short-term sensitivity of atom interferometers, by demonstrating a record rotation sensitivity of $100$ nrad.s$^{-1}/\\sqrt{\\rm Hz}$ in a cold-atom gyroscope of $11$ cm$^2$ Sagnac area. We also demonstrate a rotation stability of $1$ nrad.s$^{-1}$ after $10^4$ s of integration, improving previous results by an order of magnitude. We expect that the continuous operation will allow cold-atom inertial sensors with long interrogation time to reach their full sensitivity, determined by the quantum noise limit.

  9. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  10. Molecular photons interfaced with alkali atoms.

    Science.gov (United States)

    Siyushev, Petr; Stein, Guilherme; Wrachtrup, Jörg; Gerhardt, Ilja

    2014-05-01

    Future quantum communication will rely on the integration of single-photon sources, quantum memories and systems with strong single-photon nonlinearities. Two key parameters are crucial for the single-photon source: a high photon flux with a very small bandwidth, and a spectral match to other components of the system. Atoms or ions may act as single-photon sources--owing to their narrowband emission and their intrinsic spectral match to other atomic systems--and can serve as quantum nonlinear elements. Unfortunately, their emission rates are still limited, even for highly efficient cavity designs. Single solid-state emitters such as single organic dye molecules are significantly brighter and allow for narrowband photons; they have shown potential in a variety of quantum optical experiments but have yet to be interfaced with other components such as stationary memory qubits. Here we describe the optical interaction between Fourier-limited photons from a single organic molecule and atomic alkali vapours, which can constitute an efficient quantum memory. Single-photon emission rates reach up to several hundred thousand counts per second and show a high spectral brightness of 30,000 detectable photons per second per megahertz of bandwidth. The molecular emission is robust and we demonstrate perfect tuning to the spectral transitions of the sodium D line and efficient filtering, even for emitters at ambient conditions. In addition, we achieve storage of molecular photons originating from a single dibenzanthanthrene molecule in atomic sodium vapour. Given the large set of molecular emission lines matching to atomic transitions, our results enable the combination of almost ideal single-photon sources with various atomic vapours, such that experiments with giant single-photon nonlinearities, mediated, for example, by Rydberg atoms, become feasible.

  11. Atomic homodyne detection of weak atomic transitions.

    Science.gov (United States)

    Gunawardena, Mevan; Elliott, D S

    2007-01-26

    We have developed a two-color, two-pathway coherent control technique to detect and measure weak optical transitions in atoms by coherently beating the transition amplitude for the weak transition with that of a much stronger transition. We demonstrate the technique in atomic cesium, exciting the 6s(2)S(1/2) --> 8s(2)S(1/2) transition via a strong two-photon transition and a weak controllable Stark-induced transition. We discuss the enhancement in the signal-to-noise ratio for this measurement technique over that of direct detection of the weak transition rate, and project future refinements that may further improve its sensitivity and application to the measurement of other weak atomic interactions.

  12. The Software Atom

    CERN Document Server

    Javanainen, Juha

    2016-01-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  13. The Software Atom

    Science.gov (United States)

    Javanainen, Juha

    2017-03-01

    By putting together an abstract view on quantum mechanics and a quantum-optics picture of the interactions of an atom with light, we develop a corresponding set of C++ classes that set up the numerical analysis of an atom with an arbitrary set of angular-momentum degenerate energy levels, arbitrary light fields, and an applied magnetic field. As an example, we develop and implement perturbation theory to compute the polarizability of an atom in an experimentally relevant situation.

  14. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  15. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1995-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is promarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  16. Atomicity in Electronic Commerce,

    Science.gov (United States)

    1996-01-01

    tremendous demand for the ability to electronically buy and sell goods over networks. Electronic commerce has inspired a large variety of work... commerce . It then briefly surveys some major types of electronic commerce pointing out flaws in atomicity. We pay special attention to the atomicity...problems of proposals for digital cash. The paper presents two examples of highly atomic electronic commerce systems: NetBill and Cryptographic Postage Indicia.

  17. Dephasing in an atom

    OpenAIRE

    2011-01-01

    When an atom in vacuum is near a surface of a dielectric the energy of a fluctuating electromagnetic field depends on a distance between them resulting, as known, in the force called van der Waals one. Besides this fluctuation phenomenon there is one associated with formation of a mean electric field which is equivalent to an order parameter. In this case atomic electrons are localized within atomic distances close to the atom and the total ground state energy is larger, compared to the bare ...

  18. Laser trapping of {sup 21}Na atoms

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Zheng-Tian

    1994-09-01

    This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, {sup 21}Na atoms were produced by bombarding {sup 24}Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The {sup 21}Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined.

  19. Stout: Cloudy's Atomic and Molecular Database

    CERN Document Server

    Lykins, M L; Kisielius, R; Chatzikos, M; Porter, R L; van Hoof, P A M; Williams, R J R; Keenan, F P; Stancil, P C

    2015-01-01

    We describe a new atomic and molecular database we developed for use in the spectral synthesis code Cloudy. The design of Stout is driven by the data needs of Cloudy, which simulates molecular, atomic, and ionized gas with kinetic temperatures 2.8 K < T < 1e10 K and densities spanning the low to high-density limits. The radiation field between photon energies $10^{-8}$ Ry and 100 MeV is considered, along with all atoms and ions of the lightest 30 elements, and ~100 molecules. For ease of maintenance, the data are stored in a format as close as possible to the original data sources. Few data sources include the full range of data we need. We describe how we fill in the gaps in the data or extrapolate rates beyond their tabulated range. We tabulate data sources both for the atomic spectroscopic parameters and for collision data for the next release of Cloudy. This is not intended as a review of the current status of atomic data, but rather a description of the features of the database which we will build ...

  20. Phase shift in atom interferometry due to spacetime curvature

    CERN Document Server

    Asenbaum, Peter; Kovachy, Tim; Brown, Daniel D; Hogan, Jason M; Kasevich, Mark A

    2016-01-01

    We present a single-source dual atom interferometer and utilize it as a gradiometer for precise gravitational measurements. The macroscopic separation between interfering atomic wave packets (as large as 16 cm) reveals the interplay of recoil effects and gravitational curvature from a nearby Pb source mass. The gradiometer baseline is set by the laser wavelength and pulse timings, which can be measured to high precision. Using a long drift time and large momentum transfer atom optics, the gradiometer reaches a resolution of $3 \\times 10^{-9}$ s$^{-2}$ per shot and measures a 1 rad phase shift induced by the source mass.

  1. A cold 87Rb atomic beam

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Jia; Feng Yan-Ying; Xue Hong-Bo; Zhou Zhao-Ying; Zhang Wen-Dong

    2011-01-01

    We demonstrate an experimental setup for the production of a beam source of cold 87Rb atoms.The atoms are extracted from a trapped cold atomic cloud in an unbalanced three-dimensional magneto-optical trap.Via a radiation pressure difference generated by a specially designed leak tunnel along one trapping laser beam,the atoms are pushed out continuously with low velocities and a high flux.The most-probable velocity in the beam is varied from 9 m/s to 19 m/s by varying the detuning of the trapping laser beams in the magneto-optical trap and the flux can be tuned up to 4× 109 s-1 by increasing the intensity of the trapping beams.We also present a simple model for describing the dependence of the beam performance on the magneto-optical trap trapping laser intensity and the detuning.

  2. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  3. Simultaneous magneto-optical trapping of lithium and ytterbium atoms towards production of ultracold polar molecules

    CERN Document Server

    Okano, M; Muramatsu, M; Doi, K; Uetake, S; Takasu, Y; Takahashi, Y

    2009-01-01

    We have successfully implemented the first simultaneous magneto-optical trapping (MOT) of lithium ($^6$Li) and ytterbium ($^{174}$Yb) atoms, towards production of ultracold polar molecules of LiYb. For this purpose, we developed the dual atomic oven which contains both atomic species as an atom source and successfully observed the spectra of the Li and Yb atoms in the atomic beams from the dual atomic oven. We constructed the vacuum chamber including the glass cell with the windows made of zinc selenium (ZnSe) for the CO$_2$ lasers, which are the useful light sources of optical trapping for evaporative and sympathetic cooling. Typical atom numbers and temperatures in the compressed MOT are 7$\\times10^3$ atoms, 640 $\\mu$K for $^6$Li, 7$\\times10^4$ atoms and 60 $\\mu$K for $^{174}$Yb, respectively.

  4. Greek Atomic Theory.

    Science.gov (United States)

    Roller, Duane H. D.

    1981-01-01

    Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)

  5. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  6. Atomic Scale Plasmonic Switch.

    Science.gov (United States)

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  7. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  8. Standard Formats for Atomic Data: the APED

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R K; Brickhouse, N S; Liedahl, D A; Raymond, J C

    2001-06-05

    Standardized formats for atomic data used in calculating emission from a collisionally-ionized plasma are described. The formats use the astronomical-standard FITS format, and are extendible to other purposes, such as photoionization data. The formats emphasize storing references to the original data source and keeping the data in as-received form, to aid in checking against the original literature.

  9. Maximally Atomic Languages

    Directory of Open Access Journals (Sweden)

    Janusz Brzozowski

    2014-05-01

    Full Text Available The atoms of a regular language are non-empty intersections of complemented and uncomplemented quotients of the language. Tight upper bounds on the number of atoms of a language and on the quotient complexities of atoms are known. We introduce a new class of regular languages, called the maximally atomic languages, consisting of all languages meeting these bounds. We prove the following result: If L is a regular language of quotient complexity n and G is the subgroup of permutations in the transition semigroup T of the minimal DFA of L, then L is maximally atomic if and only if G is transitive on k-subsets of 1,...,n for 0 <= k <= n and T contains a transformation of rank n-1.

  10. Coaxial airblast atomizers

    Science.gov (United States)

    Hardalupas, Y.; Whitelaw, J. H.

    1993-01-01

    An experimental investigation was performed to quantify the characteristics of the sprays of coaxial injectors with particular emphasis on those aspects relevant to the performance of rocket engines. Measurements for coaxial air blast atomizers were obtained using air to represent the gaseous stream and water to represent the liquid stream. A wide range of flow conditions were examined for sprays with and without swirl for gaseous streams. The parameters varied include Weber number, gas flow rate, liquid flow rate, swirl, and nozzle geometry. Measurements were made with a phase Doppler velocimeter. Major conclusions of the study focused upon droplet size as a function of Weber number, effect of gas flow rate on atomization and spray spread, effect of nozzle geometry on atomization and spread, effect of swirl on atomization, spread, jet recirculation and breakup, and secondary atomization.

  11. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  12. A compact atomic beam based system for Doppler-free laser spectroscopy of Strontium atoms

    OpenAIRE

    Verma, Gunjan; Vishwakarma, Chetan; Dharmadhikari, C. V.; Rapol, Umakant D.

    2016-01-01

    We report the construction of a simple, light weight and compact atomic beam spectroscopy cell for Strontium atoms. The cell is built using glass blowing technique and includes a simple Titanium Sublimation Pump for active pumping of the residual and background gases to maintain ultra-high vacuum. Commercially available and electrically heated dispenser source is used to generate the beam of Sr atoms. We perform spectroscopy on the $5s^2\\ ^1S_0\\longrightarrow 5s\\ 5p\\ ^1P_1$ transition to obta...

  13. Uncertainty Estimates for Theoretical Atomic and Molecular Data

    CERN Document Server

    Chung, H -K; Bartschat, K; Csaszar, A G; Drake, G W F; Kirchner, T; Kokoouline, V; Tennyson, J

    2016-01-01

    Sources of uncertainty are reviewed for calculated atomic and molecular data that are important for plasma modeling: atomic and molecular structure and cross sections for electron-atom, electron-molecule, and heavy particle collisions. We concentrate on model uncertainties due to approximations to the fundamental many-body quantum mechanical equations and we aim to provide guidelines to estimate uncertainties as a routine part of computations of data for structure and scattering.

  14. The Future of Atomic Energy

    Science.gov (United States)

    Fermi, E.

    1946-05-27

    There is definitely a technical possibility that atomic power may gradually develop into one of the principal sources of useful power. If this expectation will prove correct, great advantages can be expected to come from the fact that the weight of the fuel is almost negligible. This feature may be particularly valuable for making power available to regions of difficult access and far from deposits of coal. It also may prove a great asset in mobile power units for example in a power plant for ship propulsion. On the negative side there are some technical limitations to be applicability of atomic power of which perhaps the most serious is the impossibility of constructing light power units; also there will be some peculiar difficulties in operating atomic plants, as for example the necessity of handling highly radioactive substances which will necessitate, at least for some considerable period, the use of specially skilled personnel for the operation. But the chief obstacle in the way of developing atomic power will be the difficulty of organizing a large scale industrial development in an internationally safe way. This presents actually problems much more difficult to solve than any of the technical developments that are necessary, It will require an unusual amount of statesmanship to balance properly the necessity of allaying the international suspicion that arises from withholding technical secrets against the obvious danger of dumping the details of the procedures for an extremely dangerous new method of warfare on a world that may not yet be prepared to renounce war. Furthermore, the proper balance should be found in the relatively short time that will elapse before the 'secrets' will naturally become open knowledge by rediscovery on part of the scientists and engineers of other countries.

  15. Optical Frequency Comb Spectroscopy of Rare Earth Atoms

    Science.gov (United States)

    Swiatlowski, Jerlyn; Palm, Christopher; Joshi, Trinity; Montcrieffe, Caitlin; Jackson Kimball, Derek

    2013-05-01

    We discuss progress in our experimental program to employ optical-frequency-comb-based spectroscopy to understand the complex spectra of rare-earth atoms. We plan to carry out systematic measurements of atomic transitions in rare-earth atoms to elucidate the energy level structure and term assignment and determine presently unknown atomic state parameters. This spectroscopic information is important in view of the increasing interest in rare-earth atoms for atomic frequency standards, in astrophysical investigations of chemically peculiar stars, and in tests of fundamental physics (tests of parity and time-reversal invariance, searches for time variation of fundamental constants, etc.). We are presently studying the use of hollow cathode lamps as atomic sources for two-photon frequency comb spectroscopy. Supported by the National Science Foundation under grant PHY-0958749.

  16. Atomic size zone interaction potential between two ground-state cold atoms

    CERN Document Server

    Wang, Zhaoying; Wu, Yunhan

    2016-01-01

    The complex-source-point model are already used in the exact solution for the urtrashort pulse and nonparaxial beam. In this letter we have used the complex-source-point model to deduce the interaction potential equation for the separation R between two atoms which is comparable with the size of the atoms. We show the result and the characteristics of the numerical calculation. Since the singular point around R=0 is removed by using the complex-source-point model, so that we can obtain the result force around R=0. With the decreasing of the distance between two atoms, the force switches from the electromagnetic force to the strong force by use our equation.

  17. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Science.gov (United States)

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'')...

  18. Status of spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Existing and planned facilities using proton accelerator driven spallation neutron source are reviewed. These include new project of neutron science proposed from Japan Atomic Energy Research Institute. The present status of facility requirement and accelerator technology leads us to new era of neutron science such as neutron scattering research and nuclear transmutation study using very intense neutron source. (author)

  19. Dual-Beam Atom Laser Driven by Spinor Dynamics

    Science.gov (United States)

    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.

  20. Linear atomic quantum coupler

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...

  1. Atomic Structure Theory Lectures on Atomic Physics

    CERN Document Server

    Johnson, Walter R

    2007-01-01

    Atomic Structure Theory is a textbook for students with a background in quantum mechanics. The text is designed to give hands-on experience with atomic structure calculations. Material covered includes angular momentum methods, the central field Schrödinger and Dirac equations, Hartree-Fock and Dirac-Hartree-Fock equations, multiplet structure, hyperfine structure, the isotope shift, dipole and multipole transitions, basic many-body perturbation theory, configuration interaction, and correlation corrections to matrix elements. Numerical methods for solving the Schrödinger and Dirac eigenvalue problems and the (Dirac)-Hartree-Fock equations are given as well. B-spline basis sets are used to carry out sums arising in higher-order many-body calculations. Illustrative problems are provided, together with solutions. FORTRAN programs implementing the numerical methods in the text are included.

  2. Intense Atomic and Molecular Beams via Neon Buffer Gas Cooling

    CERN Document Server

    Patterson, David; Doyle, John M

    2008-01-01

    We realize a continuous guided beam of cold deuterated ammonia with a flux of 3e11 ND3 molecules/s and a continuous free-space beam of cold potassium with a flux of 1e16 K atoms/s. A novel feature of the buffer gas source used to produce these beams is cold neon, which, due to intermediate Knudsen number beam dynamics, produces a forward velocity and low-energy tail that is comparable to much colder helium-based sources. We expect this source to be trivially generalizable to a very wide range of atomic and molecular species with significant vapor pressure below 1000 K. This source has properties that make it a good starting point for laser cooling of molecules or atoms, cold collision studies, trapping, or nonlinear optics in buffer-gas-cooled atomic or molecular gases.

  3. Atomic and molecular supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.

    1997-12-01

    Atomic and molecular physics of supernovae is discussed with an emphasis on the importance of detailed treatments of the critical atomic and molecular processes with the best available atomic and molecular data. The observations of molecules in SN 1987A are interpreted through a combination of spectral and chemical modelings, leading to strong constraints on the mixing and nucleosynthesis of the supernova. The non-equilibrium chemistry is used to argue that carbon dust can form in the oxygen-rich clumps where the efficient molecular cooling makes the nucleation of dust grains possible. For Type Ia supernovae, the analyses of their nebular spectra lead to strong constraints on the supernova explosion models.

  4. Atom probe tomography today

    Directory of Open Access Journals (Sweden)

    Alfred Cerezo

    2007-12-01

    Full Text Available This review aims to describe and illustrate the advances in the application of atom probe tomography that have been made possible by recent developments, particularly in specimen preparation techniques (using dual-beam focused-ion beam instruments but also of the more routine use of laser pulsing. The combination of these two developments now permits atomic-scale investigation of site-specific regions within engineering alloys (e.g. at grain boundaries and in the vicinity of cracks and also the atomic-level characterization of interfaces in multilayers, oxide films, and semiconductor materials and devices.

  5. Physics of the atom

    CERN Document Server

    Wehr, Russell M; Adair, Thomas W

    1984-01-01

    The fourth edition of Physics of the Atom is designed to meet the modern need for a better understanding of the atomic age. It is an introduction suitable for students with a background in university physics and mathematical competence at the level of calculus. This book is designed to be an extension of the introductory university physics course into the realm of atomic physics. It should give students a proficiency in this field comparable to their proficiency in mechanics, heat, sound, light, and electricity.

  6. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  7. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  8. EINSTEIN, SCHROEDINGER, AND ATOM

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-03-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation and the Schrodinger equation as well. The solutions of the Einstein equations describing the stationary states of arbitrary quantum and classical systems with central symmetry have been obtained. Einstein’s atom model has been developed, and proved that atoms and atomic nuclei can be represented as standing gravitational waves

  9. Rydberg atoms in astrophysics

    CERN Document Server

    Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003

    2012-01-01

    Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.

  10. Inside the Hydrogen Atom

    CERN Document Server

    Nowakowski, M; Fierro, D Bedoya; Manjarres, A D Bermudez

    2016-01-01

    We apply the non-linear Euler-Heisenberg theory to calculate the electric field inside the hydrogen atom. We will demonstrate that the electric field calculated in the Euler-Heisenberg theory can be much smaller than the corresponding field emerging from the Maxwellian theory. In the hydrogen atom this happens only at very small distances. This effect reduces the large electric field inside the hydrogen atom calculated from the electromagnetic form-factors via the Maxwell equations. The energy content of the field is below the pair production threshold.

  11. Atomic Hong-Ou-Mandel experiment

    Science.gov (United States)

    Lopes, R.; Imanaliev, A.; Aspect, A.; Cheneau, M.; Boiron, D.; Westbrook, C. I.

    2015-04-01

    Two-particle interference is a fundamental feature of quantum mechanics, and is even less intuitive than wave-particle duality for a single particle. In this duality, classical concepts--wave or particle--are still referred to, and interference happens in ordinary space-time. On the other hand, two-particle interference takes place in a mathematical space that has no classical counterpart. Entanglement lies at the heart of this interference, as it does in the fundamental tests of quantum mechanics involving the violation of Bell's inequalities. The Hong, Ou and Mandel experiment is a conceptually simpler situation, in which the interference between two-photon amplitudes also leads to behaviour impossible to describe using a simple classical model. Here we report the realization of the Hong, Ou and Mandel experiment using atoms instead of photons. We create a source that emits pairs of atoms, and cause one atom of each pair to enter one of the two input channels of a beam-splitter, and the other atom to enter the other input channel. When the atoms are spatially overlapped so that the two inputs are indistinguishable, the atoms always emerge together in one of the output channels. This result opens the way to testing Bell's inequalities involving mechanical observables of massive particles, such as momentum, using methods inspired by quantum optics, and to testing theories of the quantum-to-classical transition. Our work also demonstrates a new way to benchmark non-classical atom sources that may be of interest for quantum information processing and quantum simulation.

  12. Dipolar exchange induced transparency with Rydberg atoms

    Science.gov (United States)

    Petrosyan, David

    2017-03-01

    A three-level atomic medium can be made transparent to a resonant probe field in the presence of a strong control field acting on an adjacent atomic transition to a long-lived state, which can be represented by a highly excited Rydberg state. The long-range interactions between the Rydberg state atoms then translate into strong, non-local, dispersive or absorptive interactions between the probe photons, which can be used to achieve deterministic quantum logic gates and single photon sources. Here we show that long-range dipole–dipole exchange interaction with one or more spins—two-level systems represented by atoms in suitable Rydberg states—can play the role of control field for the optically dense medium of atoms. This induces transparency of the medium for a number of probe photons n p not exceeding the number of spins n s , while all the excess photons are resonantly absorbed upon propagation. In the most practical case of a single spin atom prepared in the Rydberg state, the medium is thus transparent only to a single input probe photon. For larger number of spins n s , all n p ≤ n s photon components of the probe field would experience transparency but with an n p -dependent group velocity.

  13. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1998-01-01

    This volume continues the series'' cutting-edge reviews on developments in this field. Since its invention in the 1920s, electrostatic precipitation has been extensively used in industrial hygiene to remove dust and particulate matter from gases before entering the atmosphere. This combination of electrostatic precipitation is reported upon in the first chapter. Following this, chapter two reviews recent advances in the area of chemical modification in electrothermal atomization. Chapter three consists of a review which deal with advances and uses of electrothermal atomization atomic absorption spectrometry. Flow injection atomic spectroscopy has developed rapidly in recent years and after a general introduction, various aspects of this technique are looked at in chapter four. Finally, in chapter five the use of various spectrometric techniques for the determination of mercury are described.

  14. Atomic & Molecular Interactions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-07-12

    The Gordon Research Conference (GRC) on Atomic & Molecular Interactions was held at Roger Williams University, Bristol, RI. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  15. Atomical Grothendieck categories

    Directory of Open Access Journals (Sweden)

    C. Năstăsescu

    2003-01-01

    Full Text Available Motivated by the study of Gabriel dimension of a Grothendieck category, we introduce the concept of atomical Grothendieck category, which has only two localizing subcategories, and we give a classification of this type of Grothendieck categories.

  16. Atomic Interferometry Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Vertical cavity surface emitting lasers (VCSELs) is a new technology which can be used for developing high performance laser components for atom-based sensors...

  17. Optical atomic magnetometer

    Science.gov (United States)

    Budker, Dmitry; Higbie, James; Corsini, Eric P

    2013-11-19

    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  18. Cavity enhanced atomic magnetometry

    OpenAIRE

    Herbert Crepaz; Li Yuan Ley; Rainer Dumke

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage...

  19. Hirshfeld atom refinement.

    Science.gov (United States)

    Capelli, Silvia C; Bürgi, Hans-Beat; Dittrich, Birger; Grabowsky, Simon; Jayatilaka, Dylan

    2014-09-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly-l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree-Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs) are freely refined without constraints or restraints - even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's), all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules), the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å(2) as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements - an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  20. Atoms, molecules & elements

    CERN Document Server

    Graybill, George

    2007-01-01

    Young scientists will be thrilled to explore the invisible world of atoms, molecules and elements. Our resource provides ready-to-use information and activities for remedial students using simplified language and vocabulary. Students will label each part of the atom, learn what compounds are, and explore the patterns in the periodic table of elements to find calcium (Ca), chlorine (Cl), and helium (He) through hands-on activities.

  1. Theory and applications of atomic and ionic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Mitroy, J [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Safronova, M S [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Clark, Charles W, E-mail: jxm107@rsphysse.anu.edu.a, E-mail: msafrono@udel.ed, E-mail: charles.clark@nist.go [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, MD 20899-8410 (United States)

    2010-10-28

    Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards. (topical review)

  2. Accurate atom-mapping computation for biochemical reactions.

    Science.gov (United States)

    Latendresse, Mario; Malerich, Jeremiah P; Travers, Mike; Karp, Peter D

    2012-11-26

    The complete atom mapping of a chemical reaction is a bijection of the reactant atoms to the product atoms that specifies the terminus of each reactant atom. Atom mapping of biochemical reactions is useful for many applications of systems biology, in particular for metabolic engineering where synthesizing new biochemical pathways has to take into account for the number of carbon atoms from a source compound that are conserved in the synthesis of a target compound. Rapid, accurate computation of the atom mapping(s) of a biochemical reaction remains elusive despite significant work on this topic. In particular, past researchers did not validate the accuracy of mapping algorithms. We introduce a new method for computing atom mappings called the minimum weighted edit-distance (MWED) metric. The metric is based on bond propensity to react and computes biochemically valid atom mappings for a large percentage of biochemical reactions. MWED models can be formulated efficiently as Mixed-Integer Linear Programs (MILPs). We have demonstrated this approach on 7501 reactions of the MetaCyc database for which 87% of the models could be solved in less than 10 s. For 2.1% of the reactions, we found multiple optimal atom mappings. We show that the error rate is 0.9% (22 reactions) by comparing these atom mappings to 2446 atom mappings of the manually curated Kyoto Encyclopedia of Genes and Genomes (KEGG) RPAIR database. To our knowledge, our computational atom-mapping approach is the most accurate and among the fastest published to date. The atom-mapping data will be available in the MetaCyc database later in 2012; the atom-mapping software will be available within the Pathway Tools software later in 2012.

  3. Sources for charged particles; Les sources de particules chargees

    Energy Technology Data Exchange (ETDEWEB)

    Arianer, J.

    1997-09-01

    This document is a basic course on charged particle sources for post-graduate students and thematic schools on large facilities and accelerator physics. A simple but precise description of the creation and the emission of charged particles is presented. This course relies on every year upgraded reference documents. Following relevant topics are considered: electronic emission processes, technological and practical considerations on electron guns, positron sources, production of neutral atoms, ionization, plasma and discharge, different types of positive and negative ion sources, polarized particle sources, materials for the construction of ion sources, low energy beam production and transport. (N.T.).

  4. Effective potentials for atom-atom interaction at low temperatures

    OpenAIRE

    Gao, Bo

    2002-01-01

    We discuss the concept and design of effective atom-atom potentials that accurately describe any physical processes involving only states around the threshold. The existence of such potentials gives hope to a quantitative, and systematic, understanding of quantum few-atom and quantum many-atom systems at relatively low temperatures.

  5. Teleportation of Atomic States for Atoms in a Lambda Configuration

    CERN Document Server

    Guerra, E S

    2004-01-01

    In this article we discuss a scheme of teleportation of atomic states making use of three-level lambda atoms. The experimental realization proposed makes use of cavity QED involving the interaction of Rydberg atoms with a micromaser cavity prepared in a coherent state. We start presenting a scheme to prepare atomic EPR states involving two-level atoms via the interaction of these atoms with a cavity. In our scheme the cavity and some atoms play the role of auxiliary systems used to achieve the teleportation.

  6. Atomic Dipole Traps with Amplified Spontaneous Emission: A Proposal

    CERN Document Server

    Clément, Jean-François; Garreau, Jean Claude; Szriftgiser, Pascal

    2010-01-01

    We propose what we believe to be a novel type of optical source for ultra-cold atomic Far Off-Resonance optical-dipole Traps (FORTs). The source is based on an Erbium Amplified Spontaneous Emission (ASE) source that seeds a high power Erbium Doped Fiber Amplifier (EDFA). The main interest of this source is its very low coherence length, thus allowing an incoherent superposition of several trapping beams without any optical interference. The behavior of the superimposed beams is then a scalar sum greatly simplifying complex configurations. As an illustration, we report an estimation of the intensity noise of this source and an estimation of the atomic excess heating rate for an evaporative cooling experiment application. They are both found to be suitable for cold atoms experiments.

  7. Universal bosonic tetramers of dimer-atom-atom structure

    OpenAIRE

    Deltuva, A.

    2012-01-01

    Unstable four-boson states having an approximate dimer-atom-atom structure are studied using momentum-space integral equations for the four-particle transition operators. For a given Efimov trimer the universal properties of the lowest associated tetramer are determined. The impact of this tetramer on the atom-trimer and dimer-dimer collisions is analyzed. The reliability of the three-body dimer-atom-atom model is studied.

  8. Double diffraction in an atomic gravimeter

    CERN Document Server

    Malossi, Nicola; Merlet, Sébastien; Landragin, Arnaud; Santos, Franck Pereira Dos

    2009-01-01

    We demonstrate the realization of a new scheme for cold atom gravimetry based on the use of double diffraction beamsplitters recently demonstrated in \\cite{Leveque}, where the use of two retro-reflected Raman beams allows symmetric diffraction in $\\pm \\hbar k_{eff}$ momenta. Though in principle restricted to the case of zero Doppler shift, for which the two pairs of Raman beams are simultaneously resonant, we demonstrate that such diffraction pulses can remain efficient on atoms with non zero velocity, such as in a gravimeter, when modulating the frequency of one of the two Raman laser sources. We use such pulses to realize an interferometer insensitive to laser phase noise and some of the dominant systematics. This reduces the technical requirements and would allow the realization of a simple atomic gravimeter. We demonstrate a sensitivity of $1.2\\times10^{-7}g$ per shot.

  9. Photon Bubble Turbulence in Cold Atomic Gases

    CERN Document Server

    Rodrigues, João D; Ferreira, António V; Terças, Hugo; Kaiser, Robin; Mendonça, José T

    2016-01-01

    Turbulent radiation flow is ubiquitous in many physical systems where light-matter interaction becomes relevant. Photon bubbling, in particular, has been identified as the main source of turbulent radiation transport in many astrophysical objects, such as stars and accretion disks. This mechanism takes place when radiation trapping in optically dense media becomes unstable, leading to the energy dissipation from the larger to the smaller bubbles. Here, we report on the observation of photon bubble turbulence in cold atomic gases in the presence of multiple scattering of light. The instability is theoretically explained by a fluid description for the atom density coupled to a diffusive transport equation for the photons, which is known to be accurate in the multiple scattering regime investigated here. We determine the power spectrum of the atom density fluctuations, which displays an unusual $\\sim k^{-4}$ scaling, and entails a complex underlying turbulent dynamics resulting from the formation of dynamical bu...

  10. Single-atom spintronics

    Institute of Scientific and Technical Information of China (English)

    Susan Z. HUA; Matthew R. SULLIVAN; Jason N. ARMSTRONG

    2006-01-01

    Recent work on magnetic quantum point contacts (QPCs) was discussed. Complete magnetoresistance loops across Co QPCs as small as a single atom was measured. The remarkable feature of these QPCs is the rapid oscillatory decay in magnetoresistance with the increase of contact size. In addition,stepwise or quantum magnetoresistance loops are observed,resulting from varying transmission probability of the available discrete conductance channels because the sample is cycled between the ferromagnetic (F) and antiferromagnetic (AF) aligned states. Quantized conductance combined with spin dependent transmission of electron waves gives rise to a multi-channel system with a quantum domain wall acting as a valve,i.e.,a quantum spin-valve. Behavior of a few-atom QPC is built on the behavior of a single-atom QPC and hence the summarization of results as 'single-atom spintronics'. An evolutionary trace of spin-dependent electron transmission from a single atom to bulk is provided,the requisite hallmarks of artefact-free magnetoresistance is established across a QPC - stepwise or quantum magnetoresistance loops and size dependent oscillatory magnetoresistance.

  11. 微波消解-高分辨连续光源原子吸收光谱法测定锁阳和韭菜籽中的重金属元素含量%Determination of Heavy Metal Elements in Cynomorium and Leek Seeds by High Resolution Continuum Source Atomic Absorption Spectrometry with Microwave Digestion

    Institute of Scientific and Technical Information of China (English)

    胡玥; 丁玉竹; 高旭东; 李西波; 邵士俊

    2016-01-01

    The contents of heavy metals ( Cu, Pb, Cd, Cr, As, Hg) in Chinese herbal medicines ( cynomorium and leek seeds) were tested using microwave digestion-high resolution continuum source atomic absorption spectrometry ( HR-CS AAS) . The samples were digested by microwave digestion, and methods were developed for the determination of the contents of Cu by flame atomic absorption spectrometry, Pb, Cd and Cr by graphite furnace atomic absorption spectrometry, As and Hg by hydride generation atomic absorption spectrometry, respectively. The recoveries were 95. 61% ~100. 1%, the relative standard deviations ( RSDs) were 0. 8% ~3. 3%, and the correlation coefficients of R2 were 0. 999. The results showed that the contents of the above-mentioned heavy metal elements in cynomorium and leek seeds were all lower than the permitted values in the standard of “medicinal plants and preparation of green import industry standard” and National food safety standard “limited quantity of pollutants in food”. The established method are simple, rapid, accurate and reliable, and are successfully applied to analyze the contents of heavy metal elements in Chinese herbal medicines.%利用微波消解-高分辨连续光源原子吸收光谱法测定锁阳、韭菜籽两种中药材中铜( Cu)、铅( Pb)、镉( Cd)、铬( Cr)、砷( As)和汞( Hg)的含量.采用微波消解进行样品前处理,火焰原子吸收法测定其中的Cu含量,石墨炉原子吸收法测定Pb、Cd和Cr含量,氢化物发生原子吸收法测定As、Hg含量.方法线性关系良好,相关系数R2大于0.999,加标回收率为95.61%~100.1%,RSD为0.8%~3.3%,测得锁阳和韭菜籽中Cu、Pb、Cd、Cr、As和Hg的含量值均低于《药用植物及制剂进口绿色行业标准》和食品安全国家标准《食品中污染物限量》( GB2762-2012)中规定的限量指标.方法分析速率快、干扰少、精密度高,适用于中药材中重金属含量的测定.

  12. Quantum magnetism through atomic assembly

    NARCIS (Netherlands)

    Spinelli, A.

    2015-01-01

    This thesis presents an experimental study of magnetic structures, composed of only a few atoms. Those structures are first built atom-by-atom and then locally probed, both with a low-temperature STM. The technique that we use to assemble them is vertical atom manipulation, while to study their phy

  13. Sampling the Hydrogen Atom

    Directory of Open Access Journals (Sweden)

    Graves N.

    2013-01-01

    Full Text Available A model is proposed for the hydrogen atom in which the electron is an objectively real particle orbiting at very near to light speed. The model is based on the postulate that certain velocity terms associated with orbiting bodies can be considered as being af- fected by relativity. This leads to a model for the atom in which the stable electron orbits are associated with orbital velocities where Gamma is n /α , leading to the idea that it is Gamma that is quantized and not angular momentum as in the Bohr and other models. The model provides a mechanism which leads to quantization of energy levels within the atom and also provides a simple mechanical explanation for the Fine Struc- ture Constant. The mechanism is closely associated with the Sampling theorem and the related phenomenon of aliasing developed in the mid-20th century by engineers at Bell labs.

  14. The Pre-Service Science Teachers' Mental Models for Concept of Atoms and Learning Difficulties

    Science.gov (United States)

    Kiray, Seyit Ahmet

    2016-01-01

    The purpose of this study is to reveal the pre-service science teachers' difficulties about the concept of atoms. The data was collected from two different sources: The Draw an Atom Test (DAAT) and face-to-face interviews. Draw an atom test (DAAT) were administered to the 142 science teacher candidates. To elaborate the results, the researcher…

  15. Korean atomic bomb victims.

    Science.gov (United States)

    Sasamoto, Yukuo

    2009-01-01

    After colonizing Korea, Japan invaded China, and subsequently initiated the Pacific War against the United States, Britain, and their allies. Towards the end of the war, U.S. warplanes dropped atomic bombs on Hiroshima and Nagasaki, which resulted in a large number of Koreans who lived in Hiroshima and Nagasaki suffering from the effects of the bombs. The objective of this paper is to examine the history of Korea atomic bomb victims who were caught in between the U.S., Japan, the Republic of Korea (South Korea) and the Democratic People's Republic of Korea (North Korea).

  16. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Day, R.D.; Russell, P.E.

    1988-12-01

    The Atomic Force Microscope (AFM) is a recently developed instrument that has achieved atomic resolution imaging of both conducting and non- conducting surfaces. Because the AFM is in the early stages of development, and because of the difficulty of building the instrument, it is currently in use in fewer than ten laboratories worldwide. It promises to be a valuable tool for obtaining information about engineering surfaces and aiding the .study of precision fabrication processes. This paper gives an overview of AFM technology and presents plans to build an instrument designed to look at engineering surfaces.

  17. Hirshfeld atom refinement

    Directory of Open Access Journals (Sweden)

    Silvia C. Capelli

    2014-09-01

    Full Text Available Hirshfeld atom refinement (HAR is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements, repeated until convergence. The importance of this iterative procedure is illustrated via the example of crystalline ammonia. The new HAR method is then applied to X-ray diffraction data of the dipeptide Gly–l-Ala measured at 12, 50, 100, 150, 220 and 295 K, using Hartree–Fock and BLYP density functional theory electron densities and three different basis sets. All positions and anisotropic displacement parameters (ADPs are freely refined without constraints or restraints – even those for hydrogen atoms. The results are systematically compared with those from neutron diffraction experiments at the temperatures 12, 50, 150 and 295 K. Although non-hydrogen-atom ADPs differ by up to three combined standard uncertainties (csu's, all other structural parameters agree within less than 2 csu's. Using our best calculations (BLYP/cc-pVTZ, recommended for organic molecules, the accuracy of determining bond lengths involving hydrogen atoms from HAR is better than 0.009 Å for temperatures of 150 K or below; for hydrogen-atom ADPs it is better than 0.006 Å2 as judged from the mean absolute X-ray minus neutron differences. These results are among the best ever obtained. Remarkably, the precision of determining bond lengths and ADPs for the hydrogen atoms from the HAR procedure is comparable with that from the neutron measurements – an outcome which is obtained with a routinely achievable resolution of the X-ray data of 0.65 Å.

  18. Optically pumped atoms

    CERN Document Server

    Happer, William; Walker, Thad

    2010-01-01

    Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

  19. Atoms in Agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, Thomas S. [University of Tennessee

    1965-01-01

    Agriculture benefits from the applications of research. Radioactive techniques have been used to study soils, plants, microbes, insects, farm animals, and new ways to use and preserve foodstuffs. Radioactive atoms are not used directly by farmers but are used in research directed by the U. S. Department of Agriculture and Atomic Energy Commission, by the agricultural experiment stations of the various states, and by numerous public and private research institutions. From such research come improved materials and methods which are used on the farm.

  20. Development of a compact cold-atom atomic clock based on coherent population trapping

    Science.gov (United States)

    Blanshan, Eric M.

    Field-grade atomic clocks capable of primary standard performance in compact physics packages would be of significant value in a variety of applications ranging from network synchronization and secure communications to GPS hold-over and inertial navigation. A cold-atom coherent population trapping (CACPT) clock featuring laser-cooled atoms and pulsed Ramsey interrogation is a strong candidate for this technology if the principal frequency shifts can be controlled and the performance degradation associated with miniaturization can be overcome. In this thesis, research focused on the development of this type of compact atomic clock is presented. To address the low atom numbers obtained in small cold-atom sources, experiments were performed in which an atomic beam was decelerated with bichromatic stimulated laser forces and loaded into a mm-scale magneto-optical trap, increasing the atom number by a factor of 12.5. A CACPT clock using the high-contrast lin||lin optical interrogation technique was developed and achieved a stability of 7 x 10-13 after one hour of integration. Doppler shifts in the clock are explained using a simple kinematic model and canceled by interrogating the atoms with a counter-propagating CPT configuration. Finally, a thorough characterization of the AC-stark effect in lin||lin CPT was performed. Observed shifts are explained in terms of contributions from coherent CPT-generating couplings and population transfer effects caused by optical pumping from incoherent light. Measurements are compared with existing and new theoretical treatments, and a laser configuration is identified that reduces clock drift from light shifts to less than 10-14 for the current system.

  1. Polarized ion source development at IUCF

    Energy Technology Data Exchange (ETDEWEB)

    Derenchuk, V.; Brown, R.; Wedekind, M. (Indiana University Cyclotron Facility, Bloomington, Indiana 47408 (United States))

    1993-12-05

    The IUCF high intensity polarized ion source (HIPIOS) has been completed and installed in the 600 kV terminal. The design was originally based on the source in operation at TUNL, which employs cold ([similar to]30 K) atomic beam technology and an electron cyclotron resonance ionizer. Development of the reliability and intensity of the atomic beam source will be described. An atomic beam flux of 5.0[times]10[sup 16] atoms/sec is estimated to be incident on the ECR ionizer. Preliminary testing of a multiple grid, high conductance, extraction system on the ECR ionizer has resulted in an extracted current of 500 [mu]A attributable to the atomic beam, as measured 30 cm downstream of the ECR ionizer. After a mass analysis magnet, 245 [mu]A are measured with a normalized emittance of 0.78 [pi]-mm-mrad.

  2. UNIFIED MODEL FOR SPLASH DROPLETS AND SUSPENDED MIST OF ATOMIZED FLOW

    Institute of Scientific and Technical Information of China (English)

    LIU Shi-he; SUN Xiao-fei; LUO Jing

    2008-01-01

    In this article, the unified mathematical model for splash droplets and suspended mist of atomized flow was established, which classifies the atomized sources into the splash source and the suspended source. For the splash source, the Lagrangian method was used to simulate the random motion of splash water droplets, and for the suspended source the theory of air-water two-phase flow was used to simulate the mist flow moving in particle clouds. The rainfall intensity of the atomized flow was obtained by summarizing the rainfall intensities relative to the above two types of atomized sources. Both experimental data and prototype observation data were used for the verification of the mathematical model. For both the distribution of rainfall intensity, and the outer edge of the atomized flow, the simulation results are in agreement with the experimental data or prototype observation data.

  3. Atomism, Pragmatism, Holism.

    Science.gov (United States)

    Miller, John P.

    1986-01-01

    Examines three world views influencing curriculum development--atomism (underpinning competency-based education), pragmatism (promoting inquiry-based approaches), amd holism (associated with confluent or Waldorf education). Holism embodies the perennial philosophy and attempts to integrate cognitive, affective, and transpersonal dimensions,…

  4. Chiral atomically thin films

    Science.gov (United States)

    Kim, Cheol-Joo; Sánchez-Castillo, A.; Ziegler, Zack; Ogawa, Yui; Noguez, Cecilia; Park, Jiwoong

    2016-06-01

    Chiral materials possess left- and right-handed counterparts linked by mirror symmetry. These materials are useful for advanced applications in polarization optics, stereochemistry and spintronics. In particular, the realization of spatially uniform chiral films with atomic-scale control of their handedness could provide a powerful means for developing nanodevices with novel chiral properties. However, previous approaches based on natural or grown films, or arrays of fabricated building blocks, could not offer a direct means to program intrinsic chiral properties of the film on the atomic scale. Here, we report a chiral stacking approach, where two-dimensional materials are positioned layer-by-layer with precise control of the interlayer rotation (θ) and polarity, resulting in tunable chiral properties of the final stack. Using this method, we produce left- and right-handed bilayer graphene, that is, a two-atom-thick chiral film. The film displays one of the highest intrinsic ellipticity values (6.5 deg μm-1) ever reported, and a remarkably strong circular dichroism (CD) with the peak energy and sign tuned by θ and polarity. We show that these chiral properties originate from the large in-plane magnetic moment associated with the interlayer optical transition. Furthermore, we show that we can program the chiral properties of atomically thin films layer-by-layer by producing three-layer graphene films with structurally controlled CD spectra.

  5. Atomic Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1970-01-01

    This booklet tells how scientists observe the particles and electromagnetic radiation that emerges from an atomic nucleus. The equipment used falls into two general categories: counters which count each particle as it passes by, and track detectors, which make a photographic record of the particle's track.

  6. Atomic and Molecular Processes

    Science.gov (United States)

    1980-06-25

    The topics investigated experimentally and theoretically by the Pittsburgh Atomic Sciences Institute with applications to high power laser development and atmospheric IR backgrounds are enumerated. Reports containing the detailed scientific progress in these studies are cited. Finally, a list of the journal articles describing the results of the programs, with full references, is given.

  7. Energy from the Atom.

    Science.gov (United States)

    Smith, Patricia L.

    This curriculum guide was written to supplement fifth and sixth grade science units on matter and energy. It was designed to provide more in-depth material on the atom. The first part, "Teacher Guide," contains background information, biographical sketches of persons in the history of nuclear energy, vocabulary, answer sheets, management sheets…

  8. Atomically Traceable Nanostructure Fabrication.

    Science.gov (United States)

    Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

    2015-07-17

    Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

  9. Atomic physics and reality

    CERN Multimedia

    1985-01-01

    An account of the long standing debate between Niels Bohr and Albert Einstein regarding the validity of the quantum mechanical description of atomic phenomena.With physicts, John Wheeler (Texas), John Bell (CERN), David Rohm (London), Abner Shimony (Boston), Alain Aspect (Paris)

  10. Experiments with Ξ- atoms

    Science.gov (United States)

    Batty, C. J.; Friedman, E.; Gal, A.

    1999-01-01

    Experiments with Ξ- atoms are proposed in order to study the nuclear interaction of Ξ hyperons. The production of Ξ- in the (K-,K+) reaction, the Ξ- stopping in matter, and its atomic cascade are incorporated within a realistic evaluation of the results expected for Ξ- x-ray spectra across the periodic table, using an assumed Ξ-nucleus optical potential Vopt. Several optimal targets for measuring the strong-interaction shift and width of the x-ray transition to the ``last'' atomic level observed are singled out: F, Cl, I, and Pb. The sensitivity of these observables to the parameters of Vopt is considered. The relevance of such experiments is discussed in the context of strangeness -2 nuclear physics and multistrange nuclear matter. Finally, with particular reference to searches for the H dibaryon, the properties of Ξ-d atoms are also discussed. The role of Stark mixing and its effect on S and P state capture of Ξ- by the deuteron together with estimates of the resulting probability for producing the H dibaryon are considered in detail.

  11. Toward atom probe tomography of microelectronic devices

    Science.gov (United States)

    Larson, D. J.; Lawrence, D.; Lefebvre, W.; Olson, D.; Prosa, T. J.; Reinhard, D. A.; Ulfig, R. M.; Clifton, P. H.; Bunton, J. H.; Lenz, D.; Olson, J. D.; Renaud, L.; Martin, I.; Kelly, T. F.

    2011-11-01

    Atom probe tomography and scanning transmission electron microscopy has been used to analyze a commercial microelectronics device prepared by depackaging and focused ion beam milling. Chemical and morphological data are presented from the source, drain and channel regions, and part of the gate oxide region of an Intel® i5-650 p-FET device demonstrating feasibility in using these techniques to investigate commercial chips.

  12. Probing atomic and molecular dynamics from within

    Energy Technology Data Exchange (ETDEWEB)

    Berrah, N. E-mail: berrah@wmich.edu; Bilodeau, R.C.; Ackerman, G.; Bozek, J.D.; Turri, G.; Kukk, E.; Cheng, W.T.; Snell, G

    2004-08-01

    We have investigated with unprecedented levels of detail photodetachment of negative ions and photoionization of molecules using the brightness, spectral resolution, and tunability of the Advanced Light Source at Lawrence Berkeley National Laboratory. In particular, we report here on investigations carried out in K-shell photodetachment of atomic Li{sup -} and He{sup -}. We also report on angular distribution of core-level iodine 4d photoelectrons from the HI molecule. In both cases comparison with calculations is discussed.

  13. Double-well atom trap for fluorescence detection at the Heisenberg limit

    Science.gov (United States)

    Stroescu, Ion; Hume, David B.; Oberthaler, Markus K.

    2015-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single-atom resolution. Such a sensitivity is a prerequisite for quantum metrology at a precision approaching the Heisenberg limit. Our system is based on fluorescence detection of atoms in a hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for single-atom resolution in the atom number difference.

  14. Dielectric barrier discharge source for supersonic beams

    Energy Technology Data Exchange (ETDEWEB)

    Luria, K.; Lavie, N.; Even, U. [Sackler School of Chemistry, Tel Aviv University, Tel Aviv 69978 (Israel)

    2009-10-15

    We present a new excitation source for pulsed supersonic beams. The excitation is based on dielectric barrier discharge in the beam. It produces cold beams of metastable atoms, dissociated neutral atoms from molecular precursors, and both positive and negative ions with high efficiency and reliability.

  15. AtomPy: An Open Atomic Data Curation Environment for Astrophysical Applications

    Directory of Open Access Journals (Sweden)

    Claudio Mendoza

    2014-05-01

    Full Text Available We present a cloud-computing environment, referred to as AtomPy, based on Google-Drive Sheets and Pandas (Python Data Analysis Library DataFrames to promote community-driven curation of atomic data for astrophysical applications, a stage beyond database development. The atomic model for each ionic species is contained in a multi-sheet workbook, tabulating representative sets of energy levels, A-values and electron impact effective collision strengths from different sources. The relevant issues that AtomPy intends to address are: (i data quality by allowing open access to both data producers and users; (ii comparisons of different datasets to facilitate accuracy assessments; (iii downloading to local data structures (i.e., Pandas DataFrames for further manipulation and analysis by prospective users; and (iv data preservation by avoiding the discard of outdated sets. Data processing workflows are implemented by means of IPython Notebooks, and collaborative software developments are encouraged and managed within the GitHub social network. The facilities of AtomPy are illustrated with the critical assessment of the transition probabilities for ions in the hydrogen and helium isoelectronic sequences with atomic number Z ≤ 10.

  16. Atomic Coherent Trapping and Properties of Trapped Atom

    Institute of Scientific and Technical Information of China (English)

    YANG Guo-Jian; XIA Li-Xin; XIE Min

    2006-01-01

    Based on the theory of velocity-selective coherent population trapping, we investigate an atom-laser system where a pair of counterpropagating laser fields interact with a three-level atom. The influence of the parametric condition on the properties of the system such as velocity at which the atom is selected to be trapped, time needed for finishing the coherent trapping process, and possible electromagnetically induced transparency of an altrocold atomic medium,etc., is studied.

  17. 皮带输煤巷中继站尘源特性及全自动气水雾化除尘系统研究%Research on dust source characteristics and automatic air-water atomization dedusting system in the relay station of coal belt roadway

    Institute of Scientific and Technical Information of China (English)

    齐庆杰; 董子文; 汪日生; 周新华; 杨桢

    2015-01-01

    Considering the characteristics of excessively high dust concentration and complex dust source in the re-lay station of high-loading coal belt roadway, and taking the relay station of main incline shaft of Tongxin mine as the research object, the characteristics of dust producing strength, concentration variation, and particle size distri-bution were studied by adopting the combined method of field measurement and experimental analysis.An automat-ic air-water atomization dedusting system based on multi-sensor joint monitoring was designed and developed, and it was applied to the field.The results showed that the dust producing strength of relay station was up to as high as 3.344 ×105 mg/min, giving priority to with respiratory dust, so the pollution was serious.Both the mass concentra-tion of whole dust and respiratory dust were decreased by about 85%with the operation of automatic air-water atom-ization dedusting system, and the dedusting effect was obvious.The system has a good practical popularization.%考虑高负载皮带输煤巷中继站粉尘浓度过高且尘源复杂的特点,以同忻矿主斜井中继站为研究对象,采用现场实测和实验分析相结合的方法对粉尘产生强度、浓度变化、粒径分布等特性进行研究分析,设计研发了基于多种传感器联合监测的全自动气水雾化除尘系统,并应用于现场。结果表明:中继站内粉尘产生强度高达3.344×105 mg/min,且以呼吸性粉尘为主,污染严重;全自动气水雾化除尘系统的运行使得中继站内全尘和呼尘的质量浓度均下降85%左右,降尘效果明显,具有良好的实用推广性。

  18. Intermediate-energy light sources

    CERN Document Server

    Corbett, W

    2003-01-01

    Increasingly, atomic scale information underlies scientific and technological progress in disciplines ranging from pharmaceutical development to materials synthesis to environmental remediation. While a variety of research tools are used to provide atomic scale information, synchrotron radiation has proved invaluable in this quest. The rapid growth of soft- and hard X-ray synchrotron light sources stands as stark testimony to the importance and utility of synchrotron radiation. Starting from just a handful of synchrotron light sources in the early 1970s, this burgeoning field now includes over 70 proposed, in-construction, or operating facilities in 23 countries on five continents. Along the way, synchrotron light facilities have evolved from small laboratories extracting light parasitically from storage rings designed for high-energy physics research to large, dedicated sources using the latest technology to produce extraordinarily bright photon beams. The basic layout of a multi-GeV storage ring light sourc...

  19. Selective single atom detection in a 10/sup 19/ atom background

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, G.S.; Nayfeh, M.H.; Young, J.P.; Payne, M.G.; Grossman, L.W.

    1977-06-01

    A recent energy pathways model for the de-excitation of excited helium gas (Payne et al., J. Chem. Phys. 63, 1422 (1975)) suggested that a key step He(2/sup 1/P) + He(1/sup 1/S) ..-->.. He(2/sup 1/S) + He(1/sup 1/S) had an unusually large cross section. This led to the need to measure the population of He(2/sup 1/S) as a function of time following charged-particle excitation of He(2/sup 1/P). The principle of resonance ionization spectroscopy is explained, and the ratio of He(2/sup 1/S) to direct ionization is shown as a function of laser energy per pulse. Conditions for resonance ionization of atoms in their ground states are described; studies were made of two-photon ionization of Cs--Ar mixtures with the broadened Cs(7p) as an intermediate state. The topic of photodissociation of molecules: time-resolved sources of free atoms is discussed; all of the CsI molecules in the central portion of a laser beam could be dissociated to neutral Cs and I atoms in their ground states. The method is well suited to rather direct measurements of the diffusion of a small number of alkali atoms in various gases and to a remarkably simple determination of the rate of reaction of free atoms with various other atoms or molecules. One-atom detection of Cs in a background of 10/sup 19/ atoms of Ar was demonstrated with a proportional counter. 12 figs. (RWR)

  20. Optical atomic clocks

    CERN Document Server

    Poli, N; Gill, P; Tino, G M

    2014-01-01

    In the last ten years extraordinary results in time and frequency metrology have been demonstrated. Frequency-stabilization techniques for continuous-wave lasers and femto-second optical frequency combs have enabled a rapid development of frequency standards based on optical transitions in ultra-cold neutral atoms and trapped ions. As a result, today's best performing atomic clocks tick at an optical rate and allow scientists to perform high-resolution measurements with a precision approaching a few parts in $10^{18}$. This paper reviews the history and the state of the art in optical-clock research and addresses the implementation of optical clocks in a possible future redefinition of the SI second as well as in tests of fundamental physics.

  1. Rotary cup slurry atomization

    Science.gov (United States)

    Sommer, H. T.; Marnicio, R. J.

    1983-06-01

    The theory of a two-phase flow in a rotating cup atomizer is described. The analysis considers the separation of the solid and liquid media thus realistically modeling the flow of two layers along the inner cup wall: a slurry of increasing solids concentration and a supernatent liquid layer. The analysis is based on the earlier work of Hinze and Milborn (1950) which addressed the flow within a rotary cup for a homogeneous liquid. The superimposition of a settling velocity under conditions of high centrifugal acceleration permits the extended analysis of the separation of the two phases. Appropriate boundary conditions have been applied to the film's free surface and the cup wall and to match the flow characteristics at the liquid-slurry interface. The changing slurry viscosity, increasing nonlinearly with growing solid loading, was also considered. A parameter study illustrates the potential for a cup design to provide optimal slurry and liquid film thicknesses for effective atomization.

  2. Cavity enhanced atomic magnetometry

    CERN Document Server

    Crepaz, Herbert; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  3. Cavity enhanced atomic magnetometry.

    Science.gov (United States)

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-10-20

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  4. Precision control of magneto-optically cooled rubidium atoms (Invited Paper)

    Science.gov (United States)

    Nic Chormaic, S.; Yarovitskiy, A.; Shortt, B.; Deasy, K.; Morrissey, M.

    2005-06-01

    Research interest in designing sources of cold atoms has significantly increased during the past ten years with the development of suitable laser sources for magneto-optical trapping and the further mastering of evaporative cooling in order to achieve Bose-Einstein condensation. The magneto-optical trap is now viewed as a standard research facility worldwide and has opened up many new exciting research directions in atomic physics. One area of interest is that of combining spherical microcavities with cold atomic sources in order to achieve efficient photon exchange between the cavity and atom for further understandings of cavity quantum electrodynamics. This could eventually lead to atom entanglement via photon exchange which would have implications for quantum logic design. However, initial attempts to achieve such interactions have been hindered by inadequate control and manipulation of the cold atom source. Here, we present work on designing and building an ultra-stable source of magneto-optically cooled rubidium atoms with a temperature in the tens of microKelvin range. We discuss the different cooling mechanisms involved in the process and present a suitable experimental arrangement including details on the ultra-high vacuum chamber, the laser systems being used and the source of rubidium vapour. Finally, we discuss some future direction for the research including the diffraction of atoms from gratings and micron-sized objects and the parameter control of the cloud of atoms.

  5. Atomic emission spectroscopy

    Science.gov (United States)

    Andrew, K. H.

    1975-01-01

    The relationship between the Slater-Condon theory and the conditions within the atom as revealed by experimental data was investigated. The first spectrum of Si, Rb, Cl, Br, I, Ne, Ar, and Xe-136 and the second spectrum of As, Cu, and P were determined. Methods for assessing the phase stability of fringe counting interferometers and the design of an autoranging scanning system for digitizing the output of an infrared spectrometer and recording it on magnetic tape are described.

  6. Atom Interferometry Progress

    Science.gov (United States)

    1990-04-19

    Casher effect . RECENT PUBLICATION Atom Optics, David W. Keith and David E. Pritchard, New frontiers in QED and Quantumoptics, (Plenum Press, New York...frequencies (< 10 Hz) where the passive system is least effective . The reduction of relative motion provided by the active system will allow us to use much...experimental objective will probably be a demonstration of Berry’s phase with bosons. Another possibility would be an improved measurement of the Aharonov

  7. Artificial Rydberg atom

    Energy Technology Data Exchange (ETDEWEB)

    Joe, Yong S. [Center for Computational Nanoscience, Department of Physics and Astronomy, Ball State University, Muncie, IN 47306 (United States)], E-mail: ysjoe@bsu.edu; Mkrtchian, Vanik E. [Institute for Physical Research, Armenian Academy of Sciences, Ashtarak-2, 378410, Republic of Armenia (Armenia); Lee, Sun H. [Center for Computational Nanoscience, Department of Physics and Astronomy, Ball State University, Muncie, IN 47306 (United States)

    2009-03-02

    We analyze bound states of an electron in the field of a positively charged nanoshell. We find that the binding and excitation energies of the system decrease when the radius of the nanoshell increases. We also show that the ground and the first excited states of this system have remarkably the same properties of the highly excited Rydberg states of a hydrogen-like atom, i.e., a high sensitivity to the external perturbations and long radiative lifetimes.

  8. Strange exotic atoms

    Science.gov (United States)

    Friedman, E.

    1998-08-01

    Exotic atoms of K- and Σ- are analyzed using density-dependent optical potentials constrained by a low-density limit. Emphasis is placed on radial sensitivities of the real potential. A potential depth of 180MeV inside nuclei is confirmed for K-. For Σ- a shallow attractive potential outside the nuclear surface becomes repulsive in the interior. The information content of limited data sets is demonstrated.

  9. Atomic lighthouse effect.

    Science.gov (United States)

    Máximo, C E; Kaiser, R; Courteille, Ph W; Bachelard, R

    2014-11-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease in magnetic field efficiency.

  10. The Atomic Lighthouse Effect

    CERN Document Server

    Máximo, C E; Courteille, Ph W; Bachelard, R

    2014-01-01

    We investigate the deflection of light by a cold atomic cloud when the light-matter interaction is locally tuned via the Zeeman effect using magnetic field gradients. This "lighthouse" effect is strongest in the single-scattering regime, where deviation of the incident field is largest. For optically dense samples, the deviation is reduced by collective effects, as the increase in linewidth leads to a decrease of the magnetic field efficiency.

  11. Real and Hybrid Atomic Orbitals.

    Science.gov (United States)

    Cook, D. B.; Fowler, P. W.

    1981-01-01

    Demonstrates that the Schrodinger equation for the hydrogenlike atom separates in both spheroconal and prolate spheroidal coordinates and that these separations provide a sound theoretical basis for the real and hybrid atomic orbitals. (Author/SK)

  12. Into the atom and beyond

    CERN Multimedia

    1989-01-01

    Magnifying an atom to football pitch size. The dense nucleus, carrying almost all the atomic mass, is much smaller than the ball. The players (the electrons) would see something about the size of a marble!

  13. Ghost imaging with atoms

    Science.gov (United States)

    Khakimov, R. I.; Henson, B. M.; Shin, D. K.; Hodgman, S. S.; Dall, R. G.; Baldwin, K. G. H.; Truscott, A. G.

    2016-12-01

    Ghost imaging is a counter-intuitive phenomenon—first realized in quantum optics—that enables the image of a two-dimensional object (mask) to be reconstructed using the spatio-temporal properties of a beam of particles with which it never interacts. Typically, two beams of correlated photons are used: one passes through the mask to a single-pixel (bucket) detector while the spatial profile of the other is measured by a high-resolution (multi-pixel) detector. The second beam never interacts with the mask. Neither detector can reconstruct the mask independently, but temporal cross-correlation between the two beams can be used to recover a ‘ghost’ image. Here we report the realization of ghost imaging using massive particles instead of photons. In our experiment, the two beams are formed by correlated pairs of ultracold, metastable helium atoms, which originate from s-wave scattering of two colliding Bose-Einstein condensates. We use higher-order Kapitza-Dirac scattering to generate a large number of correlated atom pairs, enabling the creation of a clear ghost image with submillimetre resolution. Future extensions of our technique could lead to the realization of ghost interference, and enable tests of Einstein-Podolsky-Rosen entanglement and Bell’s inequalities with atoms.

  14. Zitterbewegung in Cold Atoms

    Science.gov (United States)

    Penteado, Poliana; Egues, J. Carlos

    2013-03-01

    In condensed matter systems, the coupling between spatial and spin degrees of freedom through the spin-orbit (SO) interaction offers the possibility of manipulating the electron spin via its orbital motion. The proposal by Datta and Das of a `spin transistor' for example, highlights the use of the SO interaction to control the electron spin via electrical means. Recently, arrangements of crossed lasers and magnetic fields have been used to trap and cool atoms in optical lattices and also to create light-induced gauge potentials, which mimic the SO interactions in real solids. In this work, we investigate the Zitterbewegung in cold atoms by starting from the effective SO Hamiltonian derived in Ref.. Cross-dressed atoms as effective spins can provide a proper setting in which to observe this effect, as the relevant parameter range of SO strengths may be more easily attainable in this context. We find a variety of peculiar Zitterbewegung orbits in real and pseudo-spin spaces, e.g., cycloids and ellipses - all of which obtained with realistic parameters. This work is supported by FAPESP, CAPES and CNPq.

  15. Cold Strontium Ion Source for Ion Interferometry

    Science.gov (United States)

    Jackson, Jarom; Durfee, Dallin

    2015-05-01

    We are working on a cold source of Sr Ions to be used in an ion interferometer. The beam will be generated from a magneto-optical trap (MOT) of Sr atoms by optically ionizing atoms leaking out a carefully prepared hole in the MOT. A single laser cooling on the resonant transition (461 nm) in Sr should be sufficient for trapping, as we've calculated that losses to the atom beam will outweigh losses to dark states. Another laser (405 nm), together with light from the trapping laser, will drive a two photon transition in the atom beam to an autoionizing state. Supported by NSF Award No. 1205736.

  16. Design of a dual species atom interferometer for space

    CERN Document Server

    Schuldt, Thilo; Krutzik, Markus; Bote, Lluis Gesa; Gaaloul, Naceur; Hartwig, Jonas; Ahlers, Holger; Herr, Waldemar; Posso-Trujillo, Katerine; Rudolph, Jan; Seidel, Stephan; Wendrich, Thijs; Ertmer, Wolfgang; Herrmann, Sven; Kubelka-Lange, André; Milke, Alexander; Rievers, Benny; Rocco, Emanuele; Hinton, Andrew; Bongs, Kai; Oswald, Markus; Franz, Matthias; Hauth, Matthias; Peters, Achim; Bawamia, Ahmad; Wicht, Andreas; Battelier, Baptiste; Bertoldi, Andrea; Bouyer, Philippe; Landragin, Arnaud; Massonnet, Didier; Lévèque, Thomas; Wenzlawski, Andre; Hellmig, Ortwin; Windpassinger, Patrick; Sengstock, Klaus; von Klitzing, Wolf; Chaloner, Chris; Summers, David; Ireland, Philip; Mateos, Ignacio; Sopuerta, Carlos F; Sorrentino, Fiodor; Tino, Guglielmo M; Williams, Michael; Trenkel, Christian; Gerardi, Domenico; Chwalla, Michael; Burkhardt, Johannes; Johann, Ulrich; Heske, Astrid; Wille, Eric; Gehler, Martin; Cacciapuoti, Luigi; Gürlebeck, Norman; Braxmaier, Claus; Rasel, Ernst

    2014-01-01

    Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species $^{85}$Rb/$^{87}$Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry...

  17. High-resolution adaptive imaging of a single atom

    Science.gov (United States)

    Wong-Campos, J. D.; Johnson, K. G.; Neyenhuis, B.; Mizrahi, J.; Monroe, C.

    2016-09-01

    Optical imaging systems are used extensively in the life and physical sciences because of their ability to non-invasively capture details on the microscopic and nanoscopic scales. Such systems are often limited by source or detector noise, image distortions and human operator misjudgement. Here, we report a general, quantitative method to analyse and correct these errors. We use this method to identify and correct optical aberrations in an imaging system for single atoms and realize an atomic position sensitivity of ˜0.5 nm Hz-1/2 with a minimum uncertainty of 1.7 nm, allowing the direct imaging of atomic motion. This is the highest position sensitivity ever measured for an isolated atom and opens up the possibility of performing out-of-focus three-dimensional particle tracking, imaging of atoms in three-dimensional optical lattices or sensing forces at the yoctonewton (10-24 N) scale.

  18. Light-shift measurement and suppression in atomic spin gyroscope.

    Science.gov (United States)

    Fang, Jiancheng; Wan, Shuangai; Chen, Yao; Li, Rujie

    2012-11-01

    We present a method to determine and suppress the light shift in an atomic spin gyroscope. This method doesn't require additional drive source or frequency modulation, and it is based on the dynamics of an atomic spin gyroscope to determine a clean curve as a function of the frequency of the pump beam that predicts the zero light shift. We experimentally validate the method in a Cs-(129)Xe atomic spin gyroscope and verify the results through numerical simulations. This method can also be applied to an atomic spin magnetometer based on the spin-exchange relaxation-free exchange that experiences light shift. The method is useful for atomic spin devices because it can improve long-term performance and reduce the influence of the laser.

  19. MAGIA - using atom interferometry to determine the Newtonian gravitational constant

    Energy Technology Data Exchange (ETDEWEB)

    Stuhler, J; Fattori, M; Petelski, T; Tino, G M [Dipartimento di Fisica and LENS, Universita di Firenze, INFN - Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino (Finland), Italy

    2003-04-01

    We describe our experiment MAGIA (misura accurata di G mediante interferometria atomica), in which we will use atom interferometry to perform a high precision measurement of the Newtonian gravitational constant G. Free-falling laser-cooled atoms in a vertical atomic fountain will be accelerated due to the gravitational potential of nearby source masses (SMs). Detecting this acceleration with techniques of Raman atom interferometry will enable us to assign a value to G. To suppress systematic effects we will implement a double-differential measurement. This includes launching two atom clouds in a gradiometer configuration and moving the SMs to different vertical positions. We briefly summarize the general idea of the MAGIA experiment and put it in the context of other high precision G-measurements. We present the current status of the experiment and report on analyses of the expected measurement accuracy.

  20. Current Trends in Atomic Spectroscopy.

    Science.gov (United States)

    Wynne, James J.

    1983-01-01

    Atomic spectroscopy is the study of atoms/ions through their interaction with electromagnetic radiation, in particular, interactions in which radiation is absorbed or emitted with an internal rearrangement of the atom's electrons. Discusses nature of this field, its status and future, and how it is applied to other areas of physics. (JN)

  1. Problems with packaged sources in foreign countries

    Energy Technology Data Exchange (ETDEWEB)

    Abeyta, Cristy L [Los Alamos National Laboratory; Matzke, James L [Los Alamos National Laboratory; Zarling, John [Los Alamos National Laboratory; Tompkin, J. Andrew [Los Alamos National Laboratory

    2010-01-01

    The Global Threat Reduction Initiative's (GTRI) Off-Site Source Recovery Project (OSRP), which is administered by the Los Alamos National Laboratory (LANL), removes excess, unwanted, abandoned, or orphan radioactive sealed sources that pose a potential threat to national security, public health, and safety. In total, GTRI/OSRP has been able to recover more than 25,000 excess and unwanted sealed sources from over 825 sites. In addition to transuranic sources, the GTRI/OSRP mission now includes recovery of beta/gamma emitting sources, which are of concern to both the U.S. government and the International Atomic Energy Agency (IAEA). This paper provides a synopsis of cooperative efforts in foreign countries to remove excess and unwanted sealed sources by discussing three topical areas: (1) The Regional Partnership with the International Atomic Energy Agency; (2) Challenges in repatriating sealed sources; and (3) Options for repatriating sealed sources.

  2. 1979 bibliography of atomic and molecular processes. [Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-08-01

    This annotated bibliography lists 2146 works on atomic and molecular processes reported in publications dated 1979. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center, Oak Ridge National Laboratory, to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors.

  3. Deriving static atomic multipoles from the electrostatic potential.

    Science.gov (United States)

    Kramer, Christian; Bereau, Tristan; Spinn, Alexander; Liedl, Klaus R; Gedeck, Peter; Meuwly, Markus

    2013-12-23

    The description of molecular systems using multipolar electrostatics calls for automated methods to fit the necessary parameters. In this paper, we describe an open-source software package that allows fitting atomic multipoles (MTPs) from the ab initio electrostatic potential by adequate atom typing and judicious assignment of the local axis system. By enabling the simultaneous fit of several molecules and/or conformations, the package addresses issues of parameter transferability and lack of sampling for buried atoms. We illustrate the method by studying a series of small alcohol molecules, as well as various conformations of protonated butylamine.

  4. 1978 bibliography of atomic and molecular processes. [Bibliography

    Energy Technology Data Exchange (ETDEWEB)

    1980-03-01

    This annotated bibliography lists 2557 works on atomic and molecular processes reported in publications dated 1978. Sources include scientific journals, conference proceedings, and books. Each entry is designated by one or more of the 114 categories of atomic and molecular processes used by the Controlled Fusion Atomic Data Center to classify data. Also indicated is whether the work was experimental or theoretical, what energy range was covered, what reactants were investigated, and the country of origin of the first author. Following the bibliographical listing are indexes of reactants and authors.

  5. Atomic multiwave interferometer for Aharonov-Casher-phase measurements

    Science.gov (United States)

    Zhou, Min-Kang; Zhang, Ke; Duan, Xiao-Chun; Ke, Yi; Shao, Cheng-Gang; Hu, Zhong-Kun

    2016-02-01

    We present an atomic multiwave interferometer with magnetic sublevels to precisely determine the Aharonov-Casher (AC) geometric phase. Simulations show that this interferometer has sharper fringes than a normal two-wave interferometer, which means a higher phase resolution can be achieved. Moreover, atoms evolving in a single hyperfine structure state make the interferometer insensitive to the dc Stark phase shift. This dc Stark shift is one of the main noise sources in AC phase measurements. The constraint of the photon rest mass is also discussed when using this atomic interferometer to measure the Aharonov-Casher phase.

  6. Polarized ion source operation at IUCF

    Energy Technology Data Exchange (ETDEWEB)

    Derenchuk, V. [Indiana University Cyclotron Facility, Bloomington, Indiana 47408 (United States); Belov, A. [Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, 117312, Russian Federation (Russian Federation); Brown, R.; Collins, J.; Sowinski, J.; Stephenson, E.; Wedekind, M. [Indiana University Cyclotron Facility, Bloomington, Indiana 47408 (United States)

    1995-07-15

    The IUCF high intensity polarized ion source (HIPIOS), based on the source in operation at TUNL (1) and employing cold ({similar_to}30 K) atomic beam technology with an electron cyclotron resonance ionizer, has recently delivered beam to the first users. The results of the development work required to make the source operate reliably, with reasonable beam parameters are described. Methods used to measure the polarization and possible sources of unpolarized background are also discussed.

  7. Detection of Sulfur Dioxide in Preserved Fruits with High Resolution Continuum Source Atomic Absorption Spectrometry Assisted with Distillation%蒸馏-高分辨连续光源原子吸收光谱法测定果脯中二氧化硫

    Institute of Scientific and Technical Information of China (English)

    祖文川; 汪雨; 张裕祥; 李冰宁; 刘聪; 任敏

    2016-01-01

    硫在富燃空气‐乙炔火焰中可以形成CS双原子分子。CS双原子分子的吸收轮廓与原子光谱吸收类似,因此可以利用原子吸收光谱方法进行定量分析。建立了高分辨连续光源原子吸收光谱法分析果脯中二氧化硫含量的方法。果脯中的二氧化硫经酸化、蒸馏、过氧化氢氧化等过程转变为硫酸根,通过连续光源原子吸收光谱法检测。对影响二氧化硫检测灵敏度的乙炔流量、火焰高度等仪器参数进行了优化,并考察了样品中硫酸根、硫代硫酸根等不同形态硫对二氧化硫分析的干扰。优化条件下,在257.961 nm波长的检出限为52.4 mg · kg -1;相对标准偏差小于10%。应用于北京市售果脯样品二氧化硫含量测定,平均回收率在85.7%~115.7%之间。该方法具有准确快速、干扰少等优点,拓宽了原子吸收光谱法的应用范围。%The CS diatomic molecules can be transformed from sulfur in fuel‐rich air acetylene flame .The absorbance of CS can be detected with atomic absorption spectrometry as the CS line profile is similar to the atomic absorption .A novel method was established to detect the sulfur dioxide in preserved fruits with high resolution continuum source atomic absorption spectrometry . The sulfate ions can be transformed from the SO2 in preserved fruits after the experience of acidity ,distillation and oxidation with H2 O2 .The instrumental parameters influencing on the sensitivity of SO 2 determination were optimized ,including the veloci‐ty of acetylene ,the flame height ,etc .And the interference of different S species ,such as SO2 -4 ,S2 O2 -3 ,etc on the SO2 recovery was observed .In the optimal conditions ,the limit of detection under the wavelength of 257.961 nm was 52.4 mg · kg -1 ,and the relative standard deviation was below 10% .The average spiked recoveries between 85.7% and 115.7% were achieved when this method was used for real preserved

  8. Effects of dark atom excitations

    CERN Document Server

    Cudell, Jean-René; Wallemacq, Quentin

    2014-01-01

    New stable quarks and charged leptons may exist and be hidden from detection, as they are bound by Coulomb interaction in neutral dark atoms of composite dark matter. This possibility leads to fundamentally new types of indirect effects related to the excitation of such dark atoms followed by their electromagnetic de-excitation. Stable -2 charged particles, bound to primordial helium in O-helium (OHe) atoms, represent the simplest model of dark atoms. Here we consider the structure of OHe atomic levels which is a necessary input for the indirect tests of such composite dark matter scenarios, and we give the spectrum of electromagnetic transitions from the levels excited in OHe collisions.

  9. Atom lens without chromatic aberrations

    CERN Document Server

    Efremov, Maxim A; Schleich, Wolfgang P

    2012-01-01

    We propose a lens for atoms with reduced chromatic aberrations and calculate its focal length and spot size. In our scheme a two-level atom interacts with a near-resonant standing light wave formed by two running waves of slightly different wave vectors, and a far-detuned running wave propagating perpendicular to the standing wave. We show that within the Raman-Nath approximation and for an adiabatically slow atom-light interaction, the phase acquired by the atom is independent of the incident atomic velocity.

  10. Topics in atomic collision theory

    CERN Document Server

    Geltman, Sydney; Brueckner, Keith A

    1969-01-01

    Topics in Atomic Collision Theory originated in a course of graduate lectures given at the University of Colorado and at University College in London. It is recommended for students in physics and related fields who are interested in the application of quantum scattering theory to low-energy atomic collision phenomena. No attention is given to the electromagnetic, nuclear, or elementary particle domains. The book is organized into three parts: static field scattering, electron-atom collisions, and atom-atom collisions. These are in the order of increasing physical complexity and hence necessar

  11. Doping of Semiconducting Atomic Chains

    Science.gov (United States)

    Toshishige, Yamada; Kutler, Paul (Technical Monitor)

    1997-01-01

    Due to the rapid progress in atom manipulation technology, atomic chain electronics would not be a dream, where foreign atoms are placed on a substrate to form a chain, and its electronic properties are designed by controlling the lattice constant d. It has been shown theoretically that a Si atomic chain is metallic regardless of d and that a Mg atomic chain is semiconducting or insulating with a band gap modified with d. For electronic applications, it is essential to establish a method to dope a semiconducting chain, which is to control the Fermi energy position without altering the original band structure. If we replace some of the chain atoms with dopant atoms randomly, the electrons will see random potential along the chain and will be localized strongly in space (Anderson localization). However, if we replace periodically, although the electrons can spread over the chain, there will generally appear new bands and band gaps reflecting the new periodicity of dopant atoms. This will change the original band structure significantly. In order to overcome this dilemma, we may place a dopant atom beside the chain at every N lattice periods (N > 1). Because of the periodic arrangement of dopant atoms, we can avoid the unwanted Anderson localization. Moreover, since the dopant atoms do not constitute the chain, the overlap interaction between them is minimized, and the band structure modification can be made smallest. Some tight-binding results will be discussed to demonstrate the present idea.

  12. Heat transport through atomic contacts.

    Science.gov (United States)

    Mosso, Nico; Drechsler, Ute; Menges, Fabian; Nirmalraj, Peter; Karg, Siegfried; Riel, Heike; Gotsmann, Bernd

    2017-02-06

    Heat transport and dissipation at the nanoscale severely limit the scaling of high-performance electronic devices and circuits. Metallic atomic junctions serve as model systems to probe electrical and thermal transport down to the atomic level as well as quantum effects that occur in one-dimensional (1D) systems. Whereas charge transport in atomic junctions has been studied intensively in the past two decades, heat transport remains poorly characterized because it requires the combination of a high sensitivity to small heat fluxes and the formation of stable atomic contacts. Here we report heat-transfer measurements through atomic junctions and analyse the thermal conductance of single-atom gold contacts at room temperature. Simultaneous measurements of charge and heat transport reveal the proportionality of electrical and thermal conductance, quantized with the respective conductance quanta. This constitutes a verification of the Wiedemann-Franz law at the atomic scale.

  13. Atomic mechanics of solids

    CERN Document Server

    MacPherson, A K

    1990-01-01

    This volume brings together some of the presently available theoretical techniques which will be useful in the design of solid-state materials. At present, it is impossible to specify the atomic composition of a material and its macroscopic physical properties. However, the future possibilities for such a science are being laid today. This is coming about due to the development of fast, cheap computers which will be able to undertake the calculations which are necessary.Since this field of science is fairly new, it is not yet quite clear which direction of analysis will eventually prov

  14. Atom Probe Tomography 2012

    Science.gov (United States)

    Kelly, Thomas F.; Larson, David J.

    2012-08-01

    In the world of tomographic imaging, atom probe tomography (APT) occupies the high-spatial-resolution end of the spectrum. It is highly complementary to electron tomography and is applicable to a wide range of materials. The current state of APT is reviewed. Emphasis is placed on applications and data analysis as they apply to many fields of research and development including metals, semiconductors, ceramics, and organic materials. We also provide a brief review of the history and the instrumentation associated with APT and an assessment of the existing challenges in the field.

  15. Atomic data for fusion

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, H.T.; Kirkpatrick, M.I.; Alvarez, I.; Cisneros, C.; Phaneuf, R.A. (eds.); Barnett, C.F.

    1990-07-01

    This report provides a handbook of recommended cross-section and rate-coefficient data for inelastic collisions between hydrogen, helium and lithium atoms, molecules and ions, and encompasses more than 400 different reactions of primary interest in fusion research. Published experimental and theoretical data have been collected and evaluated, and the recommended data are presented in tabular, graphical and parametrized form. Processes include excitation and spectral line emission, charge exchange, ionization, stripping, dissociation and particle interchange reactions. The range of collision energies is appropriate to applications in fusion-energy research.

  16. Achieving atomic resolution

    Directory of Open Access Journals (Sweden)

    John Spence

    2002-04-01

    Full Text Available The discovery of the nanotube in 19915 by high resolution electron microscopy (HREM, following closely on the discovery of fullerenes, has initiated a new field of science known as nanoscience. (In fact the fullerene buckyball itself was first observed in 1980, by HREM1. While nanoscience now spans many disciplines, from molecular biology to quantum computing, for all of them, the HREM technique has become the indispensable tool for analyzing the atomic structure of individual bulk nanostructural elements. However this method has long been the technique of choice whenever questions of microstructural characterization arise in materials science.

  17. Chip-Scale Magnetic Source of Cold Atoms

    Science.gov (United States)

    2013-06-01

    30 3.7 The transistor motherboard and the 100 pin breakout board. . . . . . . . . . . . 31 3.8 The full structure of the slowing chip...a separate motherboard of 60 N-channel IRLB3813PbF International Rectifier MOSFET transistors. These transistors will be turned on and off by...60 wires from the slowing chip were soldered to a motherboard of 60 transistors, lined up in two rows of 30 on a 0.1 inch grid perforated prototyping

  18. Future Gravitational Wave Detectors Based on Atom Interferometry

    CERN Document Server

    Geiger, Remi

    2016-01-01

    We present the perspective of using atom interferometry for gravitational wave (GW) detection in the mHz to about 10 Hz frequency band. We focus on light-pulse atom interferometers which have been subject to intense developments in the last 25 years. We calculate the effect of the GW on the atom interferometer and present in details the atomic gradiometer configuration which has retained more attention recently. The principle of such a detector is to use free falling atoms to measure the phase of a laser, which is modified by the GW. We highlight the potential benefits of using atom interferometry compared to optical interferometry as well as the challenges which remain for the realization of an atom interferometry based GW detector. We present some of the important noise sources which are expected in such detectors and strategies to cirucumvent them. Experimental techniques related to cold atom interferometers are briefly explained. We finally present the current progress and projects in this rapidly evolvin...

  19. Large-angle illumination STEM: Toward three-dimensional atom-by-atom imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Ryo, E-mail: ishikawa@sigma.t.u-tokyo.ac.jp [Institute of Engineering Innovation, University of Tokyo, Tokyo 113-8656 (Japan); Lupini, Andrew R. [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hinuma, Yoyo [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Pennycook, Stephen J. [Department of Materials Science and Engineering, The University of Tennessee, 328 Ferris Hall, Knoxville, TN 37996 (United States)

    2015-04-15

    To fully understand and control materials and their properties, it is of critical importance to determine their atomic structures in all three dimensions. Recent revolutionary advances in electron optics – the inventions of geometric and chromatic aberration correctors as well as electron source monochromators – have provided fertile ground for performing optical depth sectioning at atomic-scale dimensions. In this study we theoretically demonstrate the imaging of top/sub-surface atomic structures and identify the depth of single dopants, single vacancies and the other point defects within materials by large-angle illumination scanning transmission electron microscopy (LAI-STEM). The proposed method also allows us to measure specimen properties such as thickness or three-dimensional surface morphology using observations from a single crystallographic orientation. - Highlights: • We theoretically demonstrate 3D near-atomic depth resolution imaging by large-angle illumination STEM. • This method can be useful to identify the depth of single dopants, single vacancies within materials. • This method can be useful to determine reconstructed surface atomic structures.

  20. High precision spectroscopy of pionic and antiprotonic atoms; Spectroscopie de precision des atomes pioniques et antiprotoniques

    Energy Technology Data Exchange (ETDEWEB)

    El-Khoury, P

    1998-04-15

    The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)

  1. Magneto-Optical Trapping of Holmium Atoms

    CERN Document Server

    Miao, J; Stratis, G; Saffman, M

    2014-01-01

    We demonstrate sub-Doppler laser cooling and magneto-optical trapping of the rare earth element Holmium. Atoms are loaded from an atomic beam source and captured in six-beam $\\sigma_+ - \\sigma_-$ molasses using a strong $J=15/2 \\leftrightarrow J=17/2$ cycling transition at $\\lambda=410.5~\\rm nm$. Due to the small difference in hyperfine splittings and Land\\'e $g$-factors in the lower and upper levels of the cooling transition the MOT is self-repumped without additional repump light, and deep sub-Doppler cooling is achieved with the magnetic trap turned on. We measure the leakage out of the cycling transition to metastable states and find a branching ratio $\\sim 10^{-5}$ which is adequate for state resolved measurements on hyperfine encoded qubits.

  2. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  3. Ghost Imaging with Atoms

    CERN Document Server

    Khakimov, R I; Shin, D K; Hodgman, S S; Dall, R G; Baldwin, K G H; Truscott, A G

    2016-01-01

    Ghost imaging is a technique -- first realized in quantum optics -- in which the image emerges from cross-correlation between particles in two separate beams. One beam passes through the object to a bucket (single-pixel) detector, while the second beam's spatial profile is measured by a high resolution (multi-pixel) detector but never interacts with the object. Neither detector can reconstruct the image independently. However, until now ghost imaging has only been demonstrated with photons. Here we report the first realisation of ghost imaging of an object using massive particles. In our experiment, the two beams are formed by correlated pairs of ultracold metastable helium atoms, originating from two colliding Bose-Einstein condensates (BECs) via $s$-wave scattering. We use the higher-order Kapitza-Dirac effect to generate the large number of correlated atom pairs required, enabling the creation of a ghost image with good visibility and sub-millimetre resolution. Future extensions could include ghost interfe...

  4. Teori Atom menurut Asy’ariyyah

    Directory of Open Access Journals (Sweden)

    Hasan Syadzili

    2015-09-01

    Full Text Available Al-Asy’ariyyah is one of school of thought in Islam came from the hand of Abu Hasan al-Asy’ari. Asy’ari’s pattern of thought tried to harmonize of both ratio and text implicating the concept of universe as thing constituted from number of atom and accident. This concept had been criticized by several figures. However, al-Asy’ariyyah assert that Allah created something in the way of atom to show His power. In addition, they consistently contend by their ontological view that God’s will is the foundation of the regularity and harmony of this universe. This opinion is important to be known came in the middle of three large school of thought: school of Salafiyah initiated by Imam Ahmad bin Hanbal known by their highly textual method in the making of text as source and instrument to understand Islam; second, school of Islamic philosophy that comprehend aqidah based on ratio as the only source of knowledge; and third, school of Mu’tazilite combine between ratio and text while making ratio as a determinant if the text founded contradict with the rational truth. So al-Asy’ariyyah give a form to their thought dynamically with several features mentioned. According to al-As’ariyyah, the reality of body or thing consists of atom known as al-juz’u alladzi la yatajazza’. This theory is improved later by al-Asy’ariyyah in order to reduce the universe to regular subjectivities which led to God’s will that qadim thus encouraging human to put a faith God as only cause of everything exists. This paper will examine carefully the theory of atom in the view of al-Asy’ariyyah, also present a discussion about the divinity that happen between the mutakallims.

  5. Atom-by-atom assembly of defect-free one-dimensional cold atom arrays

    Science.gov (United States)

    Endres, Manuel; Bernien, Hannes; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R.; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D.

    2016-11-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a platform for the deterministic preparation of regular one-dimensional arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of more than 50 atoms in less than 400 milliseconds. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach may enable controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  6. Source Water Protection Contaminant Sources

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Simplified aggregation of potential contaminant sources used for Source Water Assessment and Protection. The data is derived from IDNR, IDALS, and US EPA program...

  7. A kilobyte rewritable atomic memory

    Science.gov (United States)

    Kalff, F. E.; Rebergen, M. P.; Fahrenfort, E.; Girovsky, J.; Toskovic, R.; Lado, J. L.; Fernández-Rossier, J.; Otte, A. F.

    2016-11-01

    The advent of devices based on single dopants, such as the single-atom transistor, the single-spin magnetometer and the single-atom memory, has motivated the quest for strategies that permit the control of matter with atomic precision. Manipulation of individual atoms by low-temperature scanning tunnelling microscopy provides ways to store data in atoms, encoded either into their charge state, magnetization state or lattice position. A clear challenge now is the controlled integration of these individual functional atoms into extended, scalable atomic circuits. Here, we present a robust digital atomic-scale memory of up to 1 kilobyte (8,000 bits) using an array of individual surface vacancies in a chlorine-terminated Cu(100) surface. The memory can be read and rewritten automatically by means of atomic-scale markers and offers an areal density of 502 terabits per square inch, outperforming state-of-the-art hard disk drives by three orders of magnitude. Furthermore, the chlorine vacancies are found to be stable at temperatures up to 77 K, offering the potential for expanding large-scale atomic assembly towards ambient conditions.

  8. Can Atomic Force Microscopy Achieve Atomic Resolution in Contact Mode?

    Science.gov (United States)

    Jarvis, M. R.; Pérez, Rubén; Payne, M. C.

    2001-02-01

    Atomic force microscopy operating in the contact mode is studied using total-energy pseudopotential calculations. It is shown that, in the case of a diamond tip and a diamond surface, it is possible for a tip terminated by a single atom to sustain forces in excess of 30 nN. It is also shown that imaging at atomic resolution may be limited by blunting of the tip during lateral scanning.

  9. Recognizing nitrogen dopant atoms in graphene using atomic force microscopy

    DEFF Research Database (Denmark)

    van der Heijden, Nadine J.; Smith, Daniel; Calogero, Gaetano

    2016-01-01

    Doping graphene by heteroatoms such as nitrogen presents an attractive route to control the position of the Fermi level in the material. We prepared N-doped graphene on Cu(111) and Ir(111) surfaces via chemical vapor deposition of two different molecules. Using scanning tunneling microscopy images...... as a benchmark, we show that the position of the dopant atoms can be determined using atomic force microscopy. Specifically, the frequency shift-distance curves Delta f(z) acquired above a N atom are significantly different from the curves measured over a C atom. Similar behavior was found for N-doped graphene...

  10. Can atom-surface potential measurements test atomic structure models?

    Science.gov (United States)

    Lonij, Vincent P A; Klauss, Catherine E; Holmgren, William F; Cronin, Alexander D

    2011-06-30

    van der Waals (vdW) atom-surface potentials can be excellent benchmarks for atomic structure calculations. This is especially true if measurements are made with two different types of atoms interacting with the same surface sample. Here we show theoretically how ratios of vdW potential strengths (e.g., C₃(K)/C₃(Na)) depend sensitively on the properties of each atom, yet these ratios are relatively insensitive to properties of the surface. We discuss how C₃ ratios depend on atomic core electrons by using a two-oscillator model to represent the contribution from atomic valence electrons and core electrons separately. We explain why certain pairs of atoms are preferable to study for future experimental tests of atomic structure calculations. A well chosen pair of atoms (e.g., K and Na) will have a C₃ ratio that is insensitive to the permittivity of the surface, whereas a poorly chosen pair (e.g., K and He) will have a ratio of C₃ values that depends more strongly on the permittivity of the surface.

  11. Atomic Data: Division B / Commission 14 / Working Group Atomic Data

    CERN Document Server

    Nave, Gillian; Zhao, Gang

    2015-01-01

    This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text. Comprehensive lists of references for atomic spectra can be found in the NIST Atomic Spectra Bibliographic Databases http://physics.nist.gov/asbib.

  12. A double-well atom trap for fluorescence detection at the Heisenberg limit

    CERN Document Server

    Stroescu, Ion; Oberthaler, Markus K

    2014-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single atom resolution. Such a sensitivity is a prerequisite for going beyond quantum metrology with spin-squeezed states. Our system is based on fluorescence detection of atoms in a novel hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for the exact determination of the atom number difference.

  13. Single atoms on demand for cavity QED experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, I.

    2007-09-06

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

  14. Cold-atom gravimetry with a Bose-Einstein condensate

    Energy Technology Data Exchange (ETDEWEB)

    Debs, J. E.; Altin, P. A.; Barter, T. H.; Doering, D.; Dennis, G. R.; McDonald, G.; Close, J. D.; Robins, N. P. [Australian Centre for Quantum Atom Optics and Department of Quantum Science, Australian National University, Canberra 0200 (Australia); Anderson, R. P. [School of Physics, Monash University, Melbourne 3800 (Australia)

    2011-09-15

    We present a cold-atom gravimeter operating with a sample of Bose-condensed {sup 87}Rb atoms. Using a Mach-Zehnder configuration with the two arms separated by a two-photon Bragg transition, we observe interference fringes with a visibility of (83{+-}6)% at T=3 ms. We exploit large momentum transfer (LMT) beam splitting to increase the enclosed space-time area of the interferometer using higher-order Bragg transitions and Bloch oscillations. We also compare fringes from condensed and thermal sources and observe a reduced visibility of (58{+-}4)% for the thermal source. We suspect the loss in visibility is caused partly by wave-front aberrations, to which the thermal source is more susceptible due to its larger transverse momentum spread. Finally, we discuss briefly the potential advantages of using a coherent atomic source for LMT, and we present a simple mean-field model to demonstrate that with currently available experimental parameters, interaction-induced dephasing will not limit the sensitivity of inertial measurements using freely falling, coherent atomic sources.

  15. Optical nanofibres and neutral atoms

    CERN Document Server

    Nieddu, Thomas; Chormaic, Sile Nic

    2015-01-01

    Optical nanofibres are increasingly being used in cold atom experiments due to their versatility and the clear advantages they have when developing all-fibred systems for quantum technologies. They provide researchers with a method of overcoming the Rayleigh range for achieving high intensities in a focussed beam over a relatively long distance, and can act as a noninvasive tool for probing cold atoms. In this review article, we will briefly introduce the theory of mode propagation in an ultrathin optical fibre and highlight some of the more significant theoretical and experimental progresses to date, including the early work on atom probing, manipulation and trapping, the study of atom-dielectric surface interactions, and the more recent observation of nanofibre-mediated nonlinear optics phenomena in atomic media. The functionality of optical nanofibres in relation to the realisation of atom-photon hybrid quantum systems is also becoming more evident as some of the earlier technical challenges are surpassed ...

  16. Variational electrodynamics of Atoms

    CERN Document Server

    De Luca, Jayme

    2013-01-01

    We study extrema with velocity discontinuities for the variational electromagnetic two-body problem. Along $C^2$ segments, these broken extrema satisfy the Euler-Lagrange equations of the variational principle, which are neutral differential delay equations with state-dependent deviating arguments. At points where accelerations are not defined and velocities are discontinuous, broken extrema satisfy Weierstrass-Erdmann corner conditions that energies and momenta are continuous. Here we construct periodic broken extrema near the $C^{\\infty}$ two-body circular orbits, using piecewise-defined $C^2$ solutions of the neutral differential delay equations along regular segments and a variational approximation for the boundary-layer segments. Broken periodic extrema with an integer number of corner points bifurcate from a discrete set of circular orbits, with scales defined by the Weierstrass-Erdmann corner conditions. We consider the three cases of hydrogen, muonium and positronium atoms. In each case the broken ext...

  17. Einstein's Hydrogen Atom

    CERN Document Server

    Kim, Y S

    2011-01-01

    In 1905, Einstein formulated his special relativity for point particles. For those particles, his Lorentz covariance and energy-momentum relation are by now firmly established. How about the hydrogen atom? It is possible to perform Lorentz boosts on the proton assuming that it is a point particle. Then what happens to the electron orbit? The orbit could go through an elliptic deformation, but it is not possible to understand this problem without quantum mechanics, where the orbit is a standing wave leading to a localized probability distribution. Is this concept consistent with Einstein's Lorentz covariance? Dirac, Wigner, and Feynman contributed important building blocks for understanding this problem. The remaining problem is to assemble those blocks to construct a Lorentz-covariant picture of quantum bound states based on standing waves. It is shown possible to assemble those building blocks using harmonic oscillators.

  18. Atomic Basic Blocks

    Science.gov (United States)

    Scheler, Fabian; Mitzlaff, Martin; Schröder-Preikschat, Wolfgang

    Die Entscheidung, einen zeit- bzw. ereignisgesteuerten Ansatz für ein Echtzeitsystem zu verwenden, ist schwierig und sehr weitreichend. Weitreichend vor allem deshalb, weil diese beiden Ansätze mit äußerst unterschiedlichen Kontrollflussabstraktionen verknüpft sind, die eine spätere Migration zum anderen Paradigma sehr schwer oder gar unmöglich machen. Wir schlagen daher die Verwendung einer Zwischendarstellung vor, die unabhängig von der jeweils verwendeten Kontrollflussabstraktion ist. Für diesen Zweck verwenden wir auf Basisblöcken basierende Atomic Basic Blocks (ABB) und bauen darauf ein Werkzeug, den Real-Time Systems Compiler (RTSC) auf, der die Migration zwischen zeit- und ereignisgesteuerten Systemen unterstützt.

  19. Atomic transportation via carbon nanotubes.

    Science.gov (United States)

    Wang, Quan

    2009-01-01

    The transportation of helium atoms in a single-walled carbon nanotube is reported via molecular dynamics simulations. The efficiency of the atomic transportation is found to be dependent on the type of the applied loading and the loading rate as well as the temperature in the process. Simulations show the transportation is a result of the van der Waals force between the nanotube and the helium atoms through a kink propagation initiated in the nanotube.

  20. Nonlinear dynamics in atom optics

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wenyu; Dyrting, S.; Milburn, G.J. [Queensland Univ., St. Lucia, QLD (Australia). Dept. of Physics

    1996-12-31

    In this paper theoretical work on classical and quantum nonlinear dynamics of cold atoms is reported. The basic concepts in nonlinear dynamics are reviewed and then applied to the motion of atoms in time-dependent standing waves and to the atomic bouncer. The quantum dynamics for the cases of regular and chaotic classical dynamics is described. The effect of spontaneous emission and external noise is also discussed. 104 refs., 1 tab., 21 figs.

  1. Inertial measurement using atom interferometry

    Institute of Scientific and Technical Information of China (English)

    JIA; Aiai; YANG; Jun; YAN; Shuhua; LUO; Yukun; HU; Qingqing; WEI; Chunhua; LI; Zehuan

    2015-01-01

    The recent advances of atom interferometer and its application in precision inertial measurement are review ed. The principle,characteristics and implementation of atom interferometer are introduced and it can be used to measure gravitational acceleration,gravity gradient and rotation for its high sensitivity. We also present the principle,structure and new progress of gravimeter,gravity gradiometer and gyroscope based on atom interferometer.

  2. Atomic laser-beam finder.

    Science.gov (United States)

    Viering, Kirsten; Medellin, David; Mo, Jianyong; Raizen, Mark G

    2012-11-05

    We report on an experimental method to align a laser beam to a cloud of atoms trapped in a magneto-optical trap (MOT). We show how balanced lock-in detection leads to a very sensitive method to align the laser beam to the atoms in the plane perpendicular to the propagation direction. This provides a very reliable and fast way of aligning laser beams to atoms trapped in a MOT.

  3. Ion-atom hybrid systems

    CERN Document Server

    Willitsch, Stefan

    2014-01-01

    The study of interactions between simultaneously trapped cold ions and atoms has emerged as a new research direction in recent years. The development of ion-atom hybrid experiments has paved the way for investigating elastic, inelastic and reactive collisions between these species at very low temperatures, for exploring new cooling mechanisms of ions by atoms and for implementing new hybrid quantum systems. The present lecture reviews experimental methods, recent results and upcoming developments in this emerging field.

  4. Nuclear effects in atomic transitions

    OpenAIRE

    Pálffy, Adriana

    2011-01-01

    Atomic electrons are sensitive to the properties of the nucleus they are bound to, such as nuclear mass, charge distribution, spin, magnetization distribution, or even excited level scheme. These nuclear parameters are reflected in the atomic transition energies. A very precise determination of atomic spectra may thus reveal information about the nucleus, otherwise hardly accessible via nuclear physics experiments. This work reviews theoretical and experimental aspects of the nuclear effects ...

  5. Bloch oscillations in atom interferometry

    CERN Document Server

    Cladé, Pierre

    2014-01-01

    In Paris, we are using an atom interferometer to precisely measure the recoil velocity of an atom that absorbs a photon. In order to reach a high sensitivity, many recoils are transferred to atoms using the Bloch oscillations technique. In this lecture, I will present in details this technique and its application to high precision measurement. I will especially describe in details how this method allows us to perform an atom recoil measurement at the level of $1.3 \\times 10^{-9}$. This measurement is used in the most precise determination of the fine structure constant that is independent of quantum electrodynamics.

  6. Similarity of atoms in molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cioslowski, J.; Nanayakkara, A. (Florida State Univ., Tallahassee, FL (United States))

    1993-12-01

    Similarity of atoms in molecules is quantitatively assessed with a measure that employs electron densities within respective atomic basins. This atomic similarity measure does not rely on arbitrary assumptions concerning basis functions or 'atomic orbitals', is relatively inexpensive to compute, and has straightforward interpretation. Inspection of similarities between pairs of carbon, hydrogen, and fluorine atoms in the CH[sub 4], CH[sub 3]F, CH[sub 2]F[sub 2], CHF[sub 3], CF[sub 4], C[sub 2]H[sub 2], C[sub 2]H[sub 4], and C[sub 2]H[sub 6] molecules, calculated at the MP2/6-311G[sup **] level of theory, reveals that the atomic similarity is greatly reduced by a change in the number or the character of ligands (i.e. the atoms with nuclei linked through bond paths to the nucleus of the atom in question). On the other hand, atoms with formally identical (i.e. having the same nuclei and numbers of ligands) ligands resemble each other to a large degree, with the similarity indices greater than 0.95 for hydrogens and 0.99 for non-hydrogens. 19 refs., 6 tabs.

  7. HPAM: Hirshfeld partitioned atomic multipoles

    Science.gov (United States)

    Elking, Dennis M.; Perera, Lalith; Pedersen, Lee G.

    2012-02-01

    An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank l on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole moments and the electrostatic potential (ESP) surrounding a molecule with their reference ab initio values. In general, the HD-I atomic charges/multipoles are found to better reproduce ab initio electrostatic properties over HD atomic charges/multipoles. A systematic increase in precision for reproducing ab initio electrostatic properties is demonstrated by increasing the atomic multipole rank from l=0 (atomic charges) to l=4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank l are shown to exactly reproduce ab initio molecular multipole moments of rank L for L⩽l. In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only ( l=0) are compared with reference ab initio values. Significant errors in reproducing ab initio molecular dipole moments are found if only HD or HD-I atomic charges used. Program summaryProgram title: HPAM Catalogue identifier: AEKP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License v2 No. of lines in distributed program, including test data, etc.: 500 809 No. of bytes in distributed program, including test data, etc.: 13 424 494 Distribution format: tar.gz Programming language: C Computer: Any Operating system: Linux RAM: Typically, a few hundred megabytes Classification: 16.13 External routines: The program requires 'formatted checkpoint' files obtained from the Gaussian 03 or Gaussian 09 quantum chemistry program. Nature of problem: An ab initio

  8. Atomic, molecular, and optical physics charged particles

    CERN Document Server

    Dunning, F B

    1995-01-01

    With this volume, Methods of Experimental Physics becomes Experimental Methods in the Physical Sciences, a name change which reflects the evolution of todays science. This volume is the first of three which will provide a comprehensive treatment of the key experimental methods of atomic, molecular, and optical physics; the three volumes as a set will form an excellent experimental handbook for the field. The wide availability of tunable lasers in the pastseveral years has revolutionized the field and lead to the introduction of many new experimental methods that are covered in these volumes. Traditional methods are also included to ensure that the volumes will be a complete reference source for the field.

  9. Multi-sensor magnetoencephalography with atomic magnetometers

    Science.gov (United States)

    Johnson, Cort N.; Schwindt, P. D. D.; Weisend, M.

    2013-09-01

    The authors have detected magnetic fields from the human brain with two independent, simultaneously operating rubidium spin-exchange-relaxation-free magnetometers. Evoked responses from auditory stimulation were recorded from multiple subjects with two multi-channel magnetometers located on opposite sides of the head. Signal processing techniques enabled by multi-channel measurements were used to improve signal quality. This is the first demonstration of multi-sensor atomic magnetometer magnetoencephalography and provides a framework for developing a non-cryogenic, whole-head magnetoencephalography array for source localization.

  10. Atomic, molecular, and optical physics electromagnetic radiation

    CERN Document Server

    Dunning, F B; Lucatorto, Thomas

    1997-01-01

    Combined with Volumes 29A and 29B, this volume is a comprehensive treatment of the key experimental methods of atomic, molecular, and optical physics, as well as an excellent experimental handbook for the field. Thewide availability of tunable lasers in the past several years has revolutionized the field and lead to the introduction of many new experimental methods that are covered in these volumes. Traditional methods are also included to ensure that the volumes will be a complete reference source for the field.

  11. Linear Atom Guides: Guiding Rydberg Atoms and Progress Toward an Atom Laser

    Science.gov (United States)

    Traxler, Mallory A.

    In this thesis, I explore a variety of experiments within linear, two-wire, magnetic atom guides. Experiments include guiding of Rydberg atoms; transferring between states while keeping the atoms contained within the guide; and designing, constructing, and testing a new experimental apparatus. The ultimate goal of the atom guiding experiments is to develop a continuous atom laser. The guiding of 87Rb 59D5/2 Rydberg atoms is demonstrated. The evolution of the atoms is driven by the combined effects of dipole forces acting on the center-of-mass degree of freedom as well as internal-state transitions. Time delayed microwave and state-selective field ionization, along with ion detection, are used to investigate the evolution of the internal-state distribution as well as the Rydberg atom motion while traversing the guide. The observed decay time of the guided-atom signal is about five times that of the initial state. A population transfer between Rydberg states contributes to this lengthened lifetime, and also broadens the observed field ionization spectrum. The population transfer is attributed to thermal transitions and, to a lesser extent, initial state-mixing due to Rydberg-Rydberg collisions. Characteristic signatures in ion time-of-flight signals and spatially resolved images of ion distributions, which result from the coupled internal-state and center-of-mass dynamics, are discussed. Some groups have used a scheme to make BECs where atoms are optically pumped from one reservoir trap to a final state trap, irreversibly transferring those atoms from one trap to the other. In this context, transfer from one guided ground state to another is studied. In our setup, before the atoms enter the guide, they are pumped into the | F = 1, mF = --1> state. Using two repumpers, one tuned to the F = 1 → F' = 0 transition (R10) and the other tuned to the F = 1 → F' = 2 transition (R12), the atoms are pumped between these guided states. Magnetic reflections within the guide

  12. A Quantum Model of Atoms (the Energy Levels of Atoms).

    Science.gov (United States)

    Rafie, Francois

    2001-01-01

    Discusses the model for all atoms which was developed on the same basis as Bohr's model for the hydrogen atom. Calculates the radii and the energies of the orbits. Demonstrates how the model obeys the de Broglie's hypothesis that the moving electron exhibits both wave and particle properties. (Author/ASK)

  13. Introduction to light forces, atom cooling, and atom trapping

    OpenAIRE

    Savage, Craig,

    1995-01-01

    This paper introduces and reviews light forces, atom cooling and atom trapping. The emphasis is on the physics of the basic processes. In discussing conservative forces the semi-classical dressed states are used rather than the usual quantized field dressed states.

  14. Intermolecular atom-atom bonds in crystals - a chemical perspective.

    Science.gov (United States)

    Thakur, Tejender S; Dubey, Ritesh; Desiraju, Gautam R

    2015-03-01

    Short atom-atom distances between molecules are almost always indicative of specific intermolecular bonding. These distances may be used to assess the significance of all hydrogen bonds, including the C-H⋯O and even weaker C-H⋯F varieties.

  15. Reactions of carbon atoms in pulsed molecular beams

    Energy Technology Data Exchange (ETDEWEB)

    Reisler, H. [Univ. of Southern California, Los Angeles (United States)

    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.

  16. Bright Solitons in an Atomic Tunnel Array with Either Attractive or Repulsive Atom-Atom Interactions

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-Xue; YOU Jun; WU Ying

    2004-01-01

    @@ Taking a coherent state representation, we derive the nonlinear Schrodinger-type differential-difference equations from the quantized model of an array of traps containing Bose-Einstein condensates and linked by the tunnelling process among the adjacent traps. It is shown that no matter whether two-body interactions among atoms are repulsive or attractive, a nearly uniform atom distribution can evolve into a bright soliton-type localized ensemble of atoms and a lump of atom distribution can also be smeared out by redistributing atoms among traps under appropriate initial phase differences of atoms in adjacent traps. These two important features originate from the tailoring effect of the initial phase conditions in coherent tunnelling processes, which differs crucially from the previous tailoring effect coming mainly from the periodicity of optical lattices.

  17. Principles and calibration of collinear photofragmentation and atomic absorption spectroscopy

    Science.gov (United States)

    Sorvajärvi, Tapio; Toivonen, Juha

    2014-06-01

    The kinetics of signal formation in collinear photofragmentation and atomic absorption spectroscopy (CPFAAS) are discussed, and theoretical equations describing the relation between the concentration of the target molecule and the detected atomic absorption in case of pure and impure samples are derived. The validity of the equation for pure samples is studied experimentally by comparing measured target molecule concentrations to concentrations determined using two other independent techniques. Our study shows that CPFAAS is capable of measuring target molecule concentrations from parts per billion (ppb) to hundreds of parts per million (ppm) in microsecond timescale. Moreover, the possibility to extend the dynamic range to cover eight orders of magnitude with a proper selection of fragmentation light source is discussed. The maximum deviation between the CPFAAS technique and a reference measurement technique is found to be less than 5 %. In this study, potassium chloride vapor and atomic potassium are used as a target molecule and a probed atom, respectively.

  18. Heralded single photon absorption by a single atom

    CERN Document Server

    Piro, Nicolas; Schuck, Carsten; Almendros, Marc; Huwer, Jan; Ghosh, Joyee; Haase, Albrecht; Hennrich, Markus; Dubin, Francois; Eschner, Jürgen

    2010-01-01

    The emission and absorption of single photons by single atomic particles is a fundamental limit of matter-light interaction, manifesting its quantum mechanical nature. At the same time, as a controlled process it is a key enabling tool for quantum technologies, such as quantum optical information technology [1, 2] and quantum metrology [3, 4, 5, 6]. Controlling both emission and absorption will allow implementing quantum networking scenarios [1, 7, 8, 9], where photonic communication of quantum information is interfaced with its local processing in atoms. In studies of single-photon emission, recent progress includes control of the shape, bandwidth, frequency, and polarization of single-photon sources [10, 11, 12, 13, 14, 15, 16, 17], and the demonstration of atom-photon entanglement [18, 19, 20]. Controlled absorption of a single photon by a single atom is much less investigated; proposals exist but only very preliminary steps have been taken experimentally such as detecting the attenuation and phase shift o...

  19. Multi-channel atomic magnetometer for magnetoencephalography: a configuration study.

    Science.gov (United States)

    Kim, Kiwoong; Begus, Samo; Xia, Hui; Lee, Seung-Kyun; Jazbinsek, Vojko; Trontelj, Zvonko; Romalis, Michael V

    2014-04-01

    Atomic magnetometers are emerging as an alternative to SQUID magnetometers for detection of biological magnetic fields. They have been used to measure both the magnetocardiography (MCG) and magnetoencephalography (MEG) signals. One of the virtues of the atomic magnetometers is their ability to operate as a multi-channel detector while using many common elements. Here we study two configurations of such a multi-channel atomic magnetometer optimized for MEG detection. We describe measurements of auditory evoked fields (AEF) from a human brain as well as localization of dipolar phantoms and auditory evoked fields. A clear N100m peak in AEF was observed with a signal-to-noise ratio of higher than 10 after averaging of 250 stimuli. Currently the intrinsic magnetic noise level is 4fTHz(-1/2) at 10Hz. We compare the performance of the two systems in regards to current source localization and discuss future development of atomic MEG systems.

  20. Atomsk: A tool for manipulating and converting atomic data files

    Science.gov (United States)

    Hirel, Pierre

    2015-12-01

    We present a libre, Open Source command-line program named Atomsk, that aims at creating and manipulating atomic systems for the purposes of ab initio calculations, classical atomistic calculations, and visualization, in the areas of computational physics and chemistry. The program can run on GNU/Linux, Apple Mac OS X, and Microsoft Windows platforms. Many file formats are supported, allowing for easy conversion of atomic configuration files. The command-line options allow to construct supercells, insert point defects (vacancies, interstitials), line defects (dislocations, cracks), plane defects (stacking faults), as well as other transformations. Several options can be applied consecutively, allowing for a comprehensive workflow from a unit cell to the final atomic system. Some modes allow to construct complex structures, or to perform specific analysis of atomic systems.

  1. New trends in atomic and molecular physics advanced technological applications

    CERN Document Server

    2013-01-01

    The field of Atomic and Molecular Physics (AMP) has reached significant advances in high–precision experimental measurement techniques. The area covers a wide spectrum ranging from conventional to new emerging multi-disciplinary areas like physics of highly charged ions (HCI), molecular physics, optical science, ultrafast laser technology etc. This book includes the important topics of atomic structure, physics of atomic collision, photoexcitation, photoionization processes, Laser cooling and trapping, Bose Einstein condensation and advanced technology applications of AMP in the fields of astronomy , astrophysics , fusion, biology and nanotechnology. This book is useful for researchers, professors, graduate, post graduate and PhD students dealing with atomic and molecular physics. The book has a wide scope with applications in neighbouring fields like plasma physics, astrophysics, cold collisions, nanotechnology and future fusion energy sources like ITER (international Thermonuclear Experimental Reactor) To...

  2. AJAC: Atomic data calculation tool in Python

    Institute of Scientific and Technical Information of China (English)

    Amani Tahat; Jordi Marti; Kaher Tahat; Ali Khwaldeh

    2013-01-01

    In this work,new features and extensions of a currently used online atomic database management system are reported.A multiplatform flexible computation package is added to the present system,to allow the calculation of various atomic radiative and collisional processes,based on simplifying the use of some existing atomic codes adopted from the literature.The interaction between users and data is facilitated by a rather extensive Python graphical user interface working online and could be installed in personal computers of different classes.In particular,this study gives an overview of the use of one model of the package models (i.e.,electron impact collisional excitation model).The accuracy of computing capability of the electron impact collisional excitation in the adopted model,which follows the distorted wave approximation approach,is enhanced by implementing the Dirac R-matrix approximation approach.The validity and utility of this approach are presented through a comparison of the current computed results with earlier available theoretical and experimental results.Finally,the source code is made available under the general public license and being distributed freely in the hope that it will be useful to a wide community of laboratory and astrophysical plasma diagnostics.

  3. X-ray holography with atomic resolution

    Science.gov (United States)

    Tegze, Miklós; Faigel, Gyula

    1996-03-01

    DIFFRACTION methods for crystallographic structure determination suffer from the so-called 'phase problem'; a diffraction pattern provides intensity but not phase information for the scattered beams, and therefore cannot be uniquely inverted to obtain the crystal structure of a sample. Holographic methods1, on the other hand, offer a means of extracting both intensity and phase information. To be useful for crystallographic applications, holography must be implemented with radiation of sufficiently small wavelength to resolve atomic-scale features2. One method, electron-emission holography3-9, uses electron waves and is a powerful tool for studying surface structure; but it cannot image the internal structure of solids because of complications arising from the highly anisotropic nature of electron scattering processes. A proposed alternative method uses X-rays2,10-13, which scatter more isotropically than electrons. Here we demonstrate the efficacy of atomic-scale X-ray holography by obtaining direct images of the three-dimensional arrangement of strontium atoms in the cubic perovskite SrTiO3. With more intense synchrotron sources for illumination, and with the development of improved X-ray detectors, X-ray holography should become a powerful general technique for unambiguous structure determination in condensed matter systems.

  4. Atom lasers: Production, properties and prospects for precision inertial measurement

    Energy Technology Data Exchange (ETDEWEB)

    Robins, N.P., E-mail: nick.robins@anu.edu.au; Altin, P.A.; Debs, J.E.; Close, J.D.

    2013-08-20

    We review experimental progress on atom lasers out-coupled from Bose–Einstein condensates, and consider the properties of such beams in the context of precision inertial sensing. The atom laser is the matter-wave analogue of the optical laser. Both devices rely on Bose-enhanced scattering to produce a macroscopically populated trapped mode that is output-coupled to produce an intense beam. In both cases, the beams often display highly desirable properties such as low divergence, high spectral flux and a simple spatial mode that make them useful in practical applications, as well as the potential to perform measurements at or below the quantum projection noise limit. Both devices display similar second-order correlations that differ from thermal sources. Because of these properties, atom lasers are a promising source for application to precision inertial measurements.

  5. Atomic toposes and countable categoricity

    OpenAIRE

    Caramello, Olivia

    2008-01-01

    We give a model-theoretic characterization of the class of geometric theories classified by an atomic topos having enough points; in particular, we show that every complete geometric theory classified by an atomic topos is countably categorical. Some applications are also discussed.

  6. A criterion for atomicity revisited

    NARCIS (Netherlands)

    Hesselink, Wim H.

    2007-01-01

    Concurrent and reactive programs are specified by their behaviours in the presence of a nondeterministic environment. In a natural way, this gives a specification (ARW) of an atomic variable. Several implementations of atomic variables by lower level primitives are known. A few years ago, we formula

  7. The Theory of Atom Lasers

    OpenAIRE

    Ballagh, R.; Savage, C. M.

    2000-01-01

    We review the current theory of atom lasers. A tutorial treatment of second quantisation and the Gross-Pitaevskii equation is presented, and basic concepts of coherence are outlined. The generic types of atom laser models are surveyed and illustrated by specific examples. We conclude with detailed treatments of the mechanisms of gain and output coupling.

  8. Bohmian picture of Rydberg atoms

    Indian Academy of Sciences (India)

    Partha Ghose; Manoj K Samal; Animesh Datta

    2002-08-01

    Unlike the previous theoretical results based on standard quantum mechanics that established the nearly elliptical shapes for the centre-of-mass motion in Rydberg atoms using numerical simulations, we show analytically that the Bohmian trajectories in Rydberg atoms are nearly elliptical.

  9. Hard sphere model of atom

    CERN Document Server

    Tsekov, R

    2014-01-01

    The finite size effect of electron and nucleus is accounted for in the model of atom. Due to their hard sphere repulsion the energy of the 1s orbital decreases and the corrections amount up to 8 % in Uranium. Several models for boundary conditions on the atomic nucleus surface are discussed as well.

  10. Manipulating collective quantum states of ultracold atoms by probing

    DEFF Research Database (Denmark)

    Wade, Andrew Christopher James

    2015-01-01

    nature of the measurement interaction and backaction is yet to be realised. This dissertation is concerned with ultracold atoms and their control via fully quantum mechanical probes. Nonclassical, squeezed and entangled states of matter and single photon sources are important for fundamental studies...

  11. Atomic spectroscopy and radiative processes

    CERN Document Server

    Landi Degl'Innocenti, Egidio

    2014-01-01

    This book describes the basic physical principles of atomic spectroscopy and the absorption and emission of radiation in astrophysical and laboratory plasmas. It summarizes the basics of electromagnetism and thermodynamics and then describes in detail the theory of atomic spectra for complex atoms, with emphasis on astrophysical applications. Both equilibrium and non-equilibrium phenomena in plasmas are considered. The interaction between radiation and matter is described, together with various types of radiation (e.g., cyclotron, synchrotron, bremsstrahlung, Compton). The basic theory of polarization is explained, as is the theory of radiative transfer for astrophysical applications. Atomic Spectroscopy and Radiative Processes bridges the gap between basic books on atomic spectroscopy and the very specialized publications for the advanced researcher: it will provide under- and postgraduates with a clear in-depth description of theoretical aspects, supported by practical examples of applications.

  12. Relativistic effects in atom gravimeters

    Science.gov (United States)

    Tan, Yu-Jie; Shao, Cheng-Gang; Hu, Zhong-Kun

    2017-01-01

    Atom interferometry is currently developing rapidly, which is now reaching sufficient precision to motivate laboratory tests of general relativity. Thus, it is extremely significant to develop a general relativistic model for atom interferometers. In this paper, we mainly present an analytical derivation process and first give a complete vectorial expression for the relativistic interferometric phase shift in an atom interferometer. The dynamics of the interferometer are studied, where both the atoms and the light are treated relativistically. Then, an appropriate coordinate transformation for the light is performed crucially to simplify the calculation. In addition, the Bordé A B C D matrix combined with quantum mechanics and the "perturbation" approach are applied to make a methodical calculation for the total phase shift. Finally, we derive the relativistic phase shift kept up to a sensitivity of the acceleration ˜1 0-14 m/s 2 for a 10 -m -long atom interferometer.

  13. Atom mapping with constraint programming.

    Science.gov (United States)

    Mann, Martin; Nahar, Feras; Schnorr, Norah; Backofen, Rolf; Stadler, Peter F; Flamm, Christoph

    2014-01-01

    Chemical reactions are rearrangements of chemical bonds. Each atom in an educt molecule thus appears again in a specific position of one of the reaction products. This bijection between educt and product atoms is not reported by chemical reaction databases, however, so that the "Atom Mapping Problem" of finding this bijection is left as an important computational task for many practical applications in computational chemistry and systems biology. Elementary chemical reactions feature a cyclic imaginary transition state (ITS) that imposes additional restrictions on the bijection between educt and product atoms that are not taken into account by previous approaches. We demonstrate that Constraint Programming is well-suited to solving the Atom Mapping Problem in this setting. The performance of our approach is evaluated for a manually curated subset of chemical reactions from the KEGG database featuring various ITS cycle layouts and reaction mechanisms.

  14. Metal-carbon clusters: The origin of the delayed atomic ion

    Science.gov (United States)

    Davis, K. M.; Peppernick, S. J.; Castleman, A. W.

    2006-04-01

    Studies of the emission of electrons from excited metal-carbon cluster systems that include the Met-Car (M8C12, where M is Ti, Zr, and V) also have revealed the evolution of a delayed atomic ion. The source of the delayed atomic ion, which involves the emission of ionized atoms on the microsecond time scale, is the focus of this investigation. By studying the delayed ionization of mixed zirconium and titanium carbon complexes produced in a laser vaporization source coupled to a time-of-flight mass spectrometer, for the first time both the zirconium and titanium delayed atomic ions were observed to be emitted in the same experiment. These studies allowed a determination that the source of the delayed atomic ion is an excited metal dicarbide. A plausible mechanism involving the excitation of a high Rydberg state of the metal dicarbide prior to an excited ion pair separation is proposed.

  15. Comparative Sensitivities of Gravitational Wave Detectors Based on Atom Interferometers and Light Interferometers

    Science.gov (United States)

    Baker, John G.; Thorpe, J. I.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe. Whether this potential advantage outweighs the additional complexity associated with including atom interferometers will require further study.

  16. Atoms in astrophysics

    CERN Document Server

    Eissner, W; Hummer, D; Percival, I

    1983-01-01

    It is hard to appreciate but nevertheless true that Michael John Seaton, known internationally for the enthusiasm and skill with which he pursues his research in atomic physics and astrophysics, will be sixty years old on the 16th of January 1983. To mark this occasion some of his colleagues and former students have prepared this volume. It contains articles that de­ scribe some of the topics that have attracted his attention since he first started his research work at University College London so many years ago. Seaton's association with University College London has now stretched over a period of some 37 years, first as an undergraduate student, then as a research student, and then, successively, as Assistant Lecturer, Lecturer, Reader, and Professor. Seaton arrived at University College London in 1946 to become an undergraduate in the Physics Department, having just left the Royal Air Force in which he had served as a navigator in the Pathfinder Force of Bomber Command. There are a number of stories of ho...

  17. Design and fabrication of diffractive atom chips for laser cooling and trapping

    CERN Document Server

    Cotter, J P; Griffin, P F; Rabey, I M; Docherty, K; Riis, E; Arnold, A S; Hinds, E A

    2016-01-01

    It has recently been shown that optical reflection gratings fabricated directly into an atom chip provide a simple and effective way to trap and cool substantial clouds of atoms [1,2]. In this article we describe how the gratings are designed and micro-fabricated and we characterise their optical properties, which determine their effectiveness as a cold atom source. We use simple scalar diffraction theory to understand how the morphology of the gratings determines the power in the diffracted beams.

  18. A New Atom Trap The Annular Shell Atom Trap (ASAT)

    CERN Document Server

    Pilloff, H S; Pilloff, Herschel S.; Horbatsch, Marko

    2002-01-01

    In the course of exploring some aspects of atom guiding in a hollow, optical fiber, a small negative potential energy well was found just in front of the repulsive or guiding barrier. This results from the optical dipole and the van der Waals potentials. The ground state for atoms bound in this negative potential well was determined by numerically solving the Schrodinger eq. and it was found that this negative well could serve as an atom trap. This trap is referred to as the Annular Shell Atom Trap or ASAT because of the geometry of the trapped atoms which are located in the locus of points defining a very thin annular shell just in front of the guiding barrier. A unique feature of the ASAT is the compression of the atoms from the entire volume to the volume of the annular shell resulting in a very high density of atoms in this trap. This trap may have applications to very low temperatures using evaporative cooling and possibly the formation of BEC. Finally, a scheme is discussed for taking advantage of the d...

  19. The Atomic and Nuclear Physics of Atomic EDMs

    Science.gov (United States)

    Chupp, Timothy

    2016-09-01

    Atomic Electric-Dipole-Moment (EDM) measurements employ low-energy atomic and precision-measurement techniques to measure the effects of elementary particle forces that affect the distribution of charge and mass in the nucleus, which is probed by the atomic electrons. Experiments and their interpretation strongly overlap atomic and nuclear physics in the experimental and theoretical problems presented. On the experimental side, the atomic EDM couples to electric fields while the magnetic dipole moment couples to magnetic fields requiring exquisite control and characerization of the magnetic fields. Measuring the tiny frequency shifts requires clock-comparisons and a large signal-to-noise ratio for frequency resolution much smaller than the linewidths, which are lmitied by observation times. To address the experimental challenges, I will discuss systematic effects related to magnetic fields and techniques of magnetometry and co-magntometery as well as optical pumping and related techniques that enhance signal-to-noise. I will also address the interpretation of atomic EDMs in terms of a set of low-energy parameters that relate to effective-field-theory coefficients, and I will empshaize the need for improved calculations from both atomic-theory and nuclear theory.

  20. Manipulating nanoscale atom-atom interactions with cavity QED

    CERN Document Server

    Pal, Arpita; Deb, Bimalendu

    2016-01-01

    We theoretically explore manipulation of interactions between excited and ground state atoms at nanoscale separations by cavity quantum electrodynamics (CQED). We develop an adiabatic molecular dressed state formalism and show that it is possible to generate Fano-Feshbach resonances between ground and long-lived excited-state atoms inside a cavity. The resonances are shown to arise due to non-adiabatic coupling near a pseudo-crossing between the dressed state potentials. We illustrate our results with a model study using fermionic $^{171}$Yb atoms in a two-modal cavity. Our study is important for manipulation of interatomic interactions at low energy by cavity field.

  1. Designing Zeeman slower for strontium atoms - towards optical atomic clock

    CERN Document Server

    Bober, Marcin; Gawlik, Wojciech

    2010-01-01

    We report on design and construction of a Zeeman slower for strontium atoms which will be used in an optical atomic clock experiment. The paper describes briefly required specifications of the device, possible solutions, and concentrates on the chosen design. The magnetic field produced by the built Zeeman slower has been measured and compared with the simulations. The system consisting of an oven and Zeeman slower are designed to produce an atomic beam of 10-12 s-1 flux and final velocity of ~30 m/s.

  2. Designing Zeeman slower for strontium atoms - towards optical atomic clock

    OpenAIRE

    Bober, Marcin; Zachorowski, Jerzy; Gawlik, Wojciech

    2010-01-01

    We report on design and construction of a Zeeman slower for strontium atoms which will be used in an optical atomic clock experiment. The paper describes briefly required specifications of the device, possible solutions, and concentrates on the chosen design. The magnetic field produced by the built Zeeman slower has been measured and compared with the simulations. The system consisting of an oven and Zeeman slower are designed to produce an atomic beam of 10-12 s-1 flux and final velocity of...

  3. Microchip-Based Trapped-Atom Clocks

    CERN Document Server

    Vuletic, Vladan; Schleier-Smith, Monika H

    2011-01-01

    This is a chapter of a recently published book entitled Atom Chips, edited by Jakob Reichel and Vladan Vuletic. The contents of this chapter include: Basic Principles; Atomic-Fountain versus Trapped-Atom Clocks; Optical-Transition Clocks versus Microwave Clocks; Clocks with Magnetically Trapped Atoms--Fundamental Limits and Experimental Demonstrations; Readout in Trapped-Atom Clocks; and Spin Squeezing.

  4. Atoms to electricity. [Booklet

    Energy Technology Data Exchange (ETDEWEB)

    1987-11-01

    This booklet explains the basic technology of nuclear fission power reactors, the nuclear fuel cycle and the role of nuclear energy as one of the domestic energy resources being developed to help meet our national energy demand. Nuclear power accounted for over 16 percent of the US electric energy supply in 1986 and was second only to coal as a source of our electric power. In the 1990s, nuclear energy is expected to provide almost 20 percent of the Nation's electricity. 38 figs., 5 tabs.

  5. An atom-by-atom assembler of defect-free arbitrary 2d atomic arrays

    CERN Document Server

    Barredo, Daniel; Lienhard, Vincent; Lahaye, Thierry; Browaeys, Antoine

    2016-01-01

    Large arrays of individually controlled atoms trapped in optical tweezers are a very promising platform for quantum engineering applications. However, to date, only disordered arrays have been demonstrated, due to the non-deterministic loading of the traps. Here, we demonstrate the preparation of fully loaded, two-dimensional arrays of up to 50 microtraps each containing a single atom, and arranged in arbitrary geometries. Starting from initially larger, half-filled matrices of randomly loaded traps, we obtain user-defined target arrays at unit filling. This is achieved with a real-time control system and a moving optical tweezers that performs a sequence of rapid atom moves depending on the initial distribution of the atoms in the arrays. These results open exciting prospects for quantum engineering with neutral atoms in tunable geometries.

  6. Development of atomic-beam resonance method to measure the nuclear moments of unstable nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, T., E-mail: sugimoto@ribf.riken.jp [SPring-8 (Japan); Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan); Kawamura, H.; Murata, J. [Rikkyo University, Department of Physics (Japan); Nagae, D.; Shimada, K. [Tokyo Institute of Technology, Department of Physics (Japan); Ueno, H.; Yoshimi, A. [RIKEN Nishina Center (Japan)

    2008-01-15

    We have been working on the development of a new technique of atomic-beam resonance method to measure the nuclear moments of unstable nuclei. In the present study, an ion-guiding system to be used as an atomic-beam source have been developed.

  7. Atomic Force Microscope Operation

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation (large file) This animation is a scientific illustration of the operation of NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA. The AFM is used to image the smallest Martian particles using a very sharp tip at the end of one of eight beams. The beam of the AFM is set into vibration and brought up to the surface of a micromachined silicon substrate. The substrate has etched in it a series of pits, 5 micrometers deep, designed to hold the Martian dust particles. The microscope then maps the shape of particles in three dimensions by scanning them with the tip. At the end of the animation is a 3D representation of the AFM image of a particle that was part of a sample informally called 'Sorceress.' The sample was delivered to the AFM on the 38th Martian day, or sol, of the mission (July 2, 2008). The image shows four round pits, only 5 microns in depth, that were micromachined into the silicon substrate. A Martian particle only one micrometer, or one millionth of a meter, across is held in the upper left pit. The rounded particle shown at the highest magnification ever seen from another world is a particle of the dust that cloaks Mars. Such dust particles color the Martian sky pink, feed storms that regularly envelop the planet and produce Mars' distinctive red soil. The AFM was developed by a Swiss-led consortium, with Imperial College London producing the silicon substrate that holds sampled particles. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  8. Role of the atom-atom scattering length and of symmetrization in unidimensional ultracold atom-diatom collisions

    Energy Technology Data Exchange (ETDEWEB)

    Quemener, G.; Launay, J.M. [Rennes-1 Univ., Institut de Physique de Rennes, UMR CNRS 6251, 35 (France); Quemener, G. [Nevada Las Vegas niv., Dept. of Chemistry, NV (United States); Honvault, P. [University of Franche-Comte, Institut UTINAM, UMR CNRS 6213, 25 - Besancon (France)

    2008-08-15

    The role of the atom-atom scattering length and of the symmetrization in ultracold atom-diatom collisions in one dimension is presented. For an ultracold atom-diatom collision and for a diatomic molecule in its highest vibrational state, inelastic rate coefficients vanish for a system composed of fermionic atoms as the atom-atom scattering length increases whereas they do not for a system composed of bosonic atoms. The differences come from the symmetrization of the wavefunction of the systems. We explain these differences by comparing the shape of the effective potentials of the atom-diatom approach. For the fermionic system, we use a zero-range interaction to model the adiabatic energies and we give a lower estimate of the atom-diatom scattering length as a function of the atom-atom scattering length. (authors)

  9. Neutron imaging of radioactive sources

    Science.gov (United States)

    Hameed, F.; Karimzadeh, S.; Zawisky, M.

    2008-08-01

    Isotopic neutron sources have been available for more than six decades. At the Atomic Institute in Vienna, operating a 250 kW TRIGA reactor, different neutron sources are in use for instrument calibration and fast neutron applications but we have only little information about their construction and densities. The knowledge of source design is essential for a complete MCNP5 modeling of the experiments. Neutron radiography (NR) and neutron tomography (NT) are the best choices for the non-destructive inspection of the source geometry and homogeneity. From the transmission analysis we gain information about the shielding components and the densities of the radio-isotopes in the cores. Three neutron sources, based on (alpha, n) reaction, have been investigated, two 239PuBe sources and one 241AmBe source. In the NR images the internal structure was clearly revealed using high-resolving scintillation and imaging plate detectors. In one source tablet a crack was detected which causes asymmetric neutron emission. The tomography inspection of strong absorbing materials is more challenging due to the low beam intensity of 1.3x105 n/cm2s at our NT instrument, and due to the beam hardening effect which requires an extension of reconstruction software. The tomographic inspection of a PuBe neutron source and appropriate measures for background and beam hardening correction are presented.

  10. Classical approach in atomic physics

    Science.gov (United States)

    Solov'ev, E. A.

    2011-12-01

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincaré section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well.

  11. Classical approach in atomic physics

    Energy Technology Data Exchange (ETDEWEB)

    Solov' ev, E.A. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

    2011-12-15

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincare section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormalization group symmetry, criterion of accuracy and so on are reviewed as well. (author)

  12. A linear atomic quantum coupler

    Energy Technology Data Exchange (ETDEWEB)

    El-Orany, Faisal A A [Department of Mathematics and computer Science, Faculty of Science, Suez Canal University 41522, Ismailia (Egypt); Wahiddin, M R B, E-mail: el_orany@hotmail.co, E-mail: faisal.orany@mimos.m, E-mail: mridza@mimos.m [Cyberspace Security Laboratory, MIMOS Berhad, Technology Park Malaysia, 57000 Kuala Lumpur (Malaysia)

    2010-04-28

    In this paper we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of which includes a localized atom. These waveguides are placed close enough to allow exchange of energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way as the Jaynes-Cummings model (JCM) and with the atom-mode system in the second waveguide via the evanescent wave. We present the Hamiltonian for this system and deduce its wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional coupler the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit a long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions the system can yield the results of the two-mode JCM.

  13. An ultracold low emittance electron source

    CERN Document Server

    Xia, G; Murray, A J; Bellan, L; Bertsche, W; Appleby, R B; Mete, O; Chattopadhyay, S

    2014-01-01

    Ultracold atom-based electron sources have recently been proposed as an alternative to the conventional photo-injectors or thermionic electron guns widely used in modern particle accelerators. The advantages of ultracold atom-based electron sources lie in the fact that the electrons extracted from the plasma (created from near threshold photo-ionization of ultracold atoms) have a very low temperature, i.e. down to tens of Kelvin. Extraction of these electrons has the potential for producing very low emittance electron bunches. These features are crucial for the next generation of particle accelerators, including free electron lasers, plasma-based accelerators and future linear colliders. The source also has many potential direct applications, including ultrafast electron diffraction (UED) and electron microscopy, due to its intrinsically high coherence. In this paper, the basic mechanism of ultracold electron beam production is discussed and our new research facility for an ultracold, low emittance electron s...

  14. Etalon-induced baseline drift and correction in atom flux sensors based on atomic absorption spectroscopy

    Science.gov (United States)

    Du, Yingge; Chambers, Scott A.

    2014-10-01

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific real-time flux sensing and control. The ultimate sensitivity and performance of these sensors are strongly affected by baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability, which has not been previously considered, and cannot be corrected using existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5% which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.

  15. Etalon-induced Baseline Drift And Correction In Atom Flux Sensors Based On Atomic Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge; Chambers, Scott A.

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific, real-time flux sensing and control. The ultimate sensitivity and performance of the sensors are strongly affected by the long-term and short term baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability which has not been previously considered or corrected by existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5%, which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.

  16. Etalon-induced baseline drift and correction in atom flux sensors based on atomic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge, E-mail: yingge.du@pnnl.gov [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Chambers, Scott A. [Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

    2014-10-20

    Atom flux sensors based on atomic absorption (AA) spectroscopy are of significant interest in thin film growth as they can provide unobtrusive, element specific real-time flux sensing and control. The ultimate sensitivity and performance of these sensors are strongly affected by baseline drift. Here we demonstrate that an etalon effect resulting from temperature changes in optical viewport housings is a major source of signal instability, which has not been previously considered, and cannot be corrected using existing methods. We show that small temperature variations in the fused silica viewports can introduce intensity modulations of up to 1.5% which in turn significantly deteriorate AA sensor performance. This undesirable effect can be at least partially eliminated by reducing the size of the beam and tilting the incident light beam off the viewport normal.

  17. Development of atomic spectroscopy technologies - Hyperfine structure of 2 period atoms using optogalvanic effects

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Nam Ic [Hankuk University of foreign studies, Seoul (Korea)

    2000-03-01

    The source of anomalous broad linewidth of 3{sup 3}P{sub 1},{sub 2},{sub 3}-3{sup 3}D{sub 2},{sub 3},4(3s') transition was explained. The broad optogalvanic spectrum was consisted of two gaussian peaks of different linewidths, and they are separated by 250 MHz. The Narrow peak, which has linewidth of room temperature, is from oxygen atoms already separated, and the shifted broad peak, which has linewidth corresponding to a temperature of 9000 K, is from weakly bound molecular ions. Obtained hyperfine spectrum of fluorine atom at the expected frequency, was too weak to analyze hyperfine structure constants. Microwave discharge might be necessary for higher density of excited state. 16 refs., 11 figs. (Author)

  18. Atomic Data: Division B / Commission 14 / Working Group Atomic Data

    OpenAIRE

    Nave, Gillian; Nahar, Sultana; Zhao, Gang

    2015-01-01

    This report summarizes laboratory measurements of atomic wavelengths, energy levels, hyperfine and isotope structure, energy level lifetimes, and oscillator strengths. Theoretical calculations of lifetimes and oscillator strengths are also included. The bibliography is limited to species of astrophysical interest. Compilations of atomic data and internet databases are also included. Papers are listed in the bibliography in alphabetical order, with a reference number in the text. Comprehensive...

  19. Quantum Repeaters and Atomic Ensembles

    DEFF Research Database (Denmark)

    Borregaard, Johannes

    a previous protocol, thereby enabling fast local processing, which greatly enhances the distribution rate. We then move on to describe our work on improving the stability of atomic clocks using entanglement. Entanglement can potentially push the stability of atomic clocks to the so-called Heisenberg limit......, which is the absolute upper limit of the stability allowed by the Heisenberg uncertainty relation. It has, however, been unclear whether entangled state’s enhanced sensitivity to noise would prevent reaching this limit. We have developed an adaptive measurement protocol, which circumvents this problem...... based on atomic ensembles....

  20. Quantum Electronics for Atomic Physics

    CERN Document Server

    Nagourney, Warren

    2010-01-01

    Quantum Electronics for Atomic Physics provides a course in quantum electronics for researchers in atomic physics. The book covers the usual topics, such as Gaussian beams, cavities, lasers, nonlinear optics and modulation techniques, but also includes a number of areas not usually found in a textbook on quantum electronics. It includes such practical matters as the enhancement of nonlinear processes in a build-up cavity, impedance matching into a cavity, laser frequencystabilization (including servomechanism theory), astigmatism in ring cavities, and atomic/molecular spectroscopic techniques

  1. Observation of relativistic antihydrogen atoms

    Science.gov (United States)

    Blanford, Glenn Delfosse, Jr.

    1997-09-01

    An observation of relativistic antihydrogen atoms is reported in this dissertation. Experiment 862 at Fermi National Accelerator Laboratory observed antihydrogen atoms produced by the interaction of a circulating beam of high momentum (3 production is outlined within. The cross section corresponds to the process where a high momentum antiproton causes e+e/sp- pair creation near a nucleus with the e+ being captured by the antiproton. Antihydrogen is the first atom made exclusively of antimatter to be detected. The observation experiment's results are the first step towards an antihydrogen spectroscopy experiment which would measure the n = 2 Lamb shift and fine structure.

  2. Review of atomic mass formula

    Energy Technology Data Exchange (ETDEWEB)

    Tachibana, Takahiro [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering

    1997-07-01

    Wapstra and Audi`s Table is famous for evaluation of experimental data of atomic nuclear masses (1993/1995 version) which estimated about 2000 kinds of nuclei. The error of atomic mass of formula is 0.3 MeV-0.8 MeV. Four kinds of atomic mass formula: JM (Jaenecke and Masson), TUYY (Tachibana, Uno, Yamada and Yamada), FRDM (Moeller, Nix, Myers and Swiatecki) and ETFSI (Aboussir, Pearson, Dutta and Tondeur) and their properties (number of parameter and error etc.) were explained. An estimation method of theoretical error of mass formula was presented. It was estimated by the theoretical error of other surrounding nuclei. (S.Y.)

  3. Dimer-atom-atom recombination in the universal four-boson system

    OpenAIRE

    Deltuva, A.

    2012-01-01

    The dimer-atom-atom recombination process in the system of four identical bosons with resonant interactions is studied. The description uses the exact Alt, Grassberger and Sandhas equations for the four-particle transition operators that are solved in the momentum-space framework. The dimer-dimer and atom-trimer channel contributions to the ultracold dimer-atom-atom recombination rate are calculated. The dimer-atom-atom recombination rate greatly exceeds the three-atom recombination rate.

  4. Atoms for space

    Energy Technology Data Exchange (ETDEWEB)

    Buden, D.

    1990-10-01

    Nuclear technology offers many advantages in an expanded solar system space exploration program. These cover a range of possible applications such as power for spacecraft, lunar and planetary surfaces, and electric propulsion; rocket propulsion for lunar and Mars vehicles; space radiation protection; water and sewage treatment; space mining; process heat; medical isotopes; and self-luminous systems. In addition, space offers opportunities to perform scientific research and develop systems that can solve problems here on Earth. These might include fusion and antimatter research, using the Moon as a source of helium-3 fusion fuel, and manufacturing perfect fusion targets. In addition, nuclear technologies can be used to reduce risk and costs of the Space Exploration Initiative. 1 fig.

  5. Contemporary Aspects of Atomic Physics

    Science.gov (United States)

    Knott, R. G. A.

    1972-01-01

    The approach generally used in writing undergraduate textbooks on Atomic and Nuclear Physics presents this branch as historical in nature. Describes the concepts of astrophysics, plasma physics and spectroscopy as contemporary and intriguing for modern scientists. (PS)

  6. Rydberg atoms: Two to tango

    Science.gov (United States)

    Löw, Robert

    2014-12-01

    The old adage that you can't tango alone is certainly true for humans. But recent experiments show that it may also be applicable to Rydberg atoms, which keep a beat through the coherent exchange of energy.

  7. Quantum information with Rydberg atoms

    DEFF Research Database (Denmark)

    Saffman, Mark; Walker, T.G.; Mølmer, Klaus

    2010-01-01

    qubits. The availability of a strong long-range interaction that can be coherently turned on and off is an enabling resource for a wide range of quantum information tasks stretching far beyond the original gate proposal. Rydberg enabled capabilities include long-range two-qubit gates, collective encoding...... of multiqubit registers, implementation of robust light-atom quantum interfaces, and the potential for simulating quantum many-body physics. The advances of the last decade are reviewed, covering both theoretical and experimental aspects of Rydberg-mediated quantum information processing.......Rydberg atoms with principal quantum number n»1 have exaggerated atomic properties including dipole-dipole interactions that scale as n4 and radiative lifetimes that scale as n3. It was proposed a decade ago to take advantage of these properties to implement quantum gates between neutral atom...

  8. Resonance Radiation and Excited Atoms

    Science.gov (United States)

    Mitchell, Allan C. G.; Zemansky, Mark W.

    2009-06-01

    1. Introduction; 2. Physical and chemical effects connected with resonance radiation; 3. Absorption lines and measurements of the lifetime of the resonance state; 4. Collision processes involving excited atoms; 5. The polarization of resonance radiation; Appendix; Index.

  9. Magnetoelectric Jones Dichroism in Atoms

    CERN Document Server

    Budker, D

    2003-01-01

    The authors suggest that atomic experiments measuring the interference between magnetic-dipole and electric-field-induced electric-dipole transition amplitudes may provide a valuable system to study magnetoelectric Jones effects.

  10. Imaging techniques: Nanoparticle atoms pinpointed

    Science.gov (United States)

    Farle, Michael

    2017-02-01

    The locations of atoms in a metallic alloy nanoparticle have been determined using a combination of electron microscopy and image simulation, revealing links between the particle's structure and magnetic properties. See Letter p.75

  11. $T^3$-interferometer for atoms

    CERN Document Server

    Zimmermann, M; Roura, A; Schleich, W P; DeSavage, S A; Davis, J P; Srinivasan, A; Narducci, F A; Werner, S A; Rasel, E M

    2016-01-01

    The quantum mechanical propagator of a massive particle in a linear gravitational potential derived already in 1927 by Earle H. Kennard \\cite{Kennard,Kennard2} contains a phase that scales with the third power of the time $T$ during which the particle experiences the corresponding force. Since in conventional atom interferometers the internal atomic states are all exposed to the same acceleration $a$, this $T^3$-phase cancels out and the interferometer phase scales as $T^2$. In contrast, by applying an external magnetic field we prepare two different accelerations $a_1$ and $a_2$ for two internal states of the atom, which translate themselves into two different cubic phases and the resulting interferometer phase scales as $T^3$. We present the theoretical background for, and summarize our progress towards experimentally realizing such a novel atom interferometer.

  12. Crowd Sourcing.

    Science.gov (United States)

    Baum, Neil

    2016-01-01

    The Internet has contributed new words and slang to our daily vernacular. A few terms, such as tweeting, texting, sexting, blogging, and googling, have become common in most vocabularies and in many languages, and are now included in the dictionary. A new buzzword making the rounds in industry is crowd sourcing, which involves outsourcing an activity, task, or problem by sending it to people or groups outside a business or a practice. Crowd sourcing allows doctors and practices to tap the wisdom of many instead of relying only on the few members of their close-knit group. This article defines "crowd sourcing," offers examples, and explains how to get started with this approach that can increase your ability to finish a task or solve problems that you don't have the time or expertise to accomplish.

  13. Laser ion source for particle accelerators

    CERN Document Server

    Sherwood, T R

    1995-01-01

    There is an interest in accelerating atomic nuclei to produce particle beams for medical therapy, atomic and nuclear physics, inertial confinement fusion and particle physics. Laser Ion Sources, in which ions are extracted from plasma created when a high power density laser beam pulse strikes a solid surface in a vacuum, are not in common use. However, some new developments in which heavy ions have been accelerated show that such sources have the potential to provide the beams required for high-energy accelerator systems.

  14. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-01-01

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th[sup 80+] and Xe[sup 53+]. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  15. The physics of Electron Beam Ion Sources

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, M.P.; Cocke, C.L.

    1990-12-31

    There are 13 Electron Beam Ion Sources in operation which produce highly charged ions, up to Th{sup 80+} and Xe{sup 53+}. Most of the sources are used to study these ions under electron impact or when recombining with gaseous or solid targets. That provides an insight into the atomic physics of these highly charged ions and into the physics of the plasma in which such ions can be found. This paper reviews the present knowledge of atomic processes, important in the production of such ions with an EBIS.

  16. Generalized Liquid Film Atomization Theory

    Institute of Scientific and Technical Information of China (English)

    HeraldoS.Couto; DemetrioBastos-Netto

    2000-01-01

    The increase of the fuel burning area required by most practical combustion processes in order to guarantee the minimum energy density rate release for their start up and operation is normally achieved by the proper choice among several existing types of atomizers.For instance.impinging and multi-impinging jets atomizers are used in rocket combustion chambers.while splash-plate atomizers find their use when wall film cooling is required.Pressure swirl atomizers,either of simplex or duplex kind,along with Y-jet or SPider Jet atomizers are used in industrial applications and in turbine combustion chambers.Notice.however,that all the types of atomizing devices listed above have one point in common:they are of pre-filming kind.i.e.,befor the droplet spray is generated,a liquid film is formed.This liquid film is broken into unstable ligaments which contract under the action of surface tension forming the droplets.Once the film thickness is estimated.the droplets'SMD(Sauter Mean Diameter)can be calculated.yielding a crucial prameter for the combustion chamber design.However,although this mechanism of droplet fromation has been under study for several decades.most of the available results.are based upon experimental data.valid for a special type of atomizer under the given sepcific conditions only.This work offers a generalized theory for theoretically estimating the SMD of sprays generated by liquid pre-filming atomizers in gereral.

  17. Decoherence Spectroscopy for Atom Interferometry

    Directory of Open Access Journals (Sweden)

    Raisa Trubko

    2016-08-01

    Full Text Available Decoherence due to photon scattering in an atom interferometer was studied as a function of laser frequency near an atomic resonance. The resulting decoherence (contrast-loss spectra will be used to calibrate measurements of tune-out wavelengths that are made with the same apparatus. To support this goal, a theoretical model of decoherence spectroscopy is presented here along with experimental tests of this model.

  18. New Developments in Atom Interferometry

    Science.gov (United States)

    1992-07-01

    interferometers can be applied to a number of experiments in fundamental physics: tests of quantum mechanics such as the Aharonov - Casher effect (6), measurement of...qualitatively new types of experiments involving inertial effects , studies of atomic and molecular properties, tests of basic quantum physics, and may ultimately...laser light as the beam splitters. Atom interferometers will make possible qualitatively new types of experiments involving inertial effects , studies of

  19. Atom gravimeters and gravitational redshift

    CERN Document Server

    Wolf, Peter; Borde, Christian J; Reynaud, Serge; Salomon, Christophe; Cohen-Tannoudji, Claude; 10.1038/nature09340

    2010-01-01

    In a recent paper, H. Mueller, A. Peters and S. Chu [A precision measurement of the gravitational redshift by the interference of matter waves, Nature 463, 926-929 (2010)] argued that atom interferometry experiments published a decade ago did in fact measure the gravitational redshift on the quantum clock operating at the very high Compton frequency associated with the rest mass of the Caesium atom. In the present Communication we show that this interpretation is incorrect.

  20. Atom as a "Dressed" Nucleus

    CERN Document Server

    Kalitvianski, V

    2008-01-01

    It is shown that electrostatic potential of atomic nucleus seen by a fast charged projectile at short distances is quite smeared due to nucleus motion around the atomic center of inertia. For example, the size of positive charge cloud in the Hydrogen ground state is much larger than the proper proton size. It is even bigger for the target atom in an excited state. Therefore the elastic scattering at large angles is generally weaker than the Rutherford one. In other words, the resulting elastic interaction with an atom at short distances is softer than the Colombian one due to a natural cutoff. In addition, the large angle scattering leads to the target atom excitations due to hitting the nucleus (inelastic processes). It is also shown that the Rutherford cross section is in fact the inclusive rather than the elastic one. These results are analogous to the QED ones. The difference and the value of the presented below non relativistic atomic calculations is in non perturbatively (exact) dressing that immediatel...

  1. Optical nanofibres and neutral atoms

    Science.gov (United States)

    Nieddu, Thomas; Gokhroo, Vandna; Chormaic, Síle Nic

    2016-05-01

    Optical nanofibres are increasingly being used in cold atom experiments due to their versatility and the clear advantages they have when developing all-fibred systems for quantum technologies. They provide researchers with a method of overcoming the Rayleigh range for achieving high intensities in a focussed beam over a relatively long distance, and can act as a noninvasive tool for probing cold atoms. In this review article, we will briefly introduce the theory of mode propagation in an ultrathin optical fibre and highlight some of the more significant theoretical and experimental progresses to date, including the early work on atom probing, manipulation and trapping, the study of atom-dielectric surface interactions, and the more recent observation of nanofibre-mediated nonlinear optics phenomena in atomic media. The functionality of optical nanofibres in relation to the realisation of atom-photon hybrid quantum systems is also becoming more evident as some of the earlier technical challenges are surpassed and, recently, several schemes to implement optical memories have been proposed. We also discuss some possible directions where this research field may head, in particular, in relation to the use of optical nanofibres that can support higher-order modes with an associated orbital angular momentum.

  2. Applications of atom interferometry - from ground to space

    Science.gov (United States)

    Schubert, Christian; Rasel, Ernst Maria; Gaaloul, Naceur; Ertmer, Wolfgang

    2016-07-01

    Atom interferometry is utilized for the measurement of rotations [1], accelerations [2] and for tests of fundamental physics [3]. In these devices, three laser light pulses separated by a free evolution time coherently manipulate the matter waves which resembles the Mach-Zehnder geometry in optics. Atom gravimeters demonstrated an accuracy of few microgal [2,4], and atom gradiometers showed a noise floor of 30 E Hz^{-1/2} [5]. Further enhancements of atom interferometers are anticipated by the integration of novel source concepts providing ultracold atoms, extending the free fall time of the atoms, and enhanced techniques for coherent manipulation. Sources providing Bose-Einstein condensates recently demontrated a flux compatible with precision experiments [6]. All of these aspects are studied in the transportable quantum gravimeter QG-1 and the very long baseline atom interferometry teststand in Hannover [7] with the goal of surpassing the microgal regime. Going beyond ground based setups, the QUANTUS collaboration exploits the unique features of a microgravity environment in drop tower experiments [8] and in a sounding rocket mission. The payloads are compact and robust atom optics experiments based on atom chips [6], enabling technology for transportable sensors on ground as a byproduct. More prominently, they are pathfinders for proposed satellite missions as tests of the universality of free fall [9] and gradiometry based on atom interferometers [10]. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM1552-1557 (QUANTUS-IV-Fallturm) and by the Deutsche Forschungsgemeinschaft in the framework of the SFB 1128 geo-Q. [1] PRL 114 063002 2015 [2] Nature 400 849 1999 [3] PRL 112 203002 2014 [4] NJP 13 065026 2011 [5] PRA 65 033608 2002 [6] NJP 17 065001 2015 [7] NJP 17 035011 2015 [8] PRL 110 093602 2013 [9

  3. Photothermal imaging of damage and undercutting to gold-coated Kapton samples exposed to atomic oxygen

    Science.gov (United States)

    Williams, A. W.; Wood, N. J.

    1996-09-01

    In this paper we describe the design and construction of a laser-based photothermal imaging system, which we have used to evaluate damage to gold-coated Kapton samples that have been exposed to atomic oxygen in a laboratory atomic oxygen source. This exposure simulates the erosive effects of atomic oxygen on spacecraft materials in low Earth orbits. In particular, thermal wave imaging studies have been carried out for materials that are susceptible to atomic oxygen erosion. The photothermal imaging method is sensitive to invisible subsurface features such as the delamination of barrier coatings used to protect vulnerable substrates.

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

    Directory of Open Access Journals (Sweden)

    Sato Tomoya

    2014-03-01

    Full Text Available 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.

  5. Atom interferometry with lithium atoms: theoretical analysis and design of an interferometer, applications; Interferometrie atomique avec l'atome de lithium: analyse theorique et construction d'un interferometre, applications

    Energy Technology Data Exchange (ETDEWEB)

    Champenois, C

    1999-12-01

    This thesis is devoted to studies which prepared the construction of an atom Mach-Zehnder interferometer. In such an interferometer, the propagating waves are spatially separated, and the internal state of the atom is not modified. The beam-splitters are diffraction gratings, consisting of standing optical waves near-resonant with an atomic transition. We use the Bloch functions to define the atom wave inside the standing wave grating and thus explain the diffraction process in different cases. We developed a nearly all-analytical model for the propagation of an atom wave inside a Mach-Zehnder interferometer. The contrast of the signal is studied for many cases: phase or amplitude gratings, effects of extra paths, effects of the main mismatches, monochromatic or lightly polychromatic sources. Finally, we discuss three interferometric measurements we think very interesting. The first, the index of refraction of gas for atomic waves, is studied in detail, with numerical simulations. The other measures we propose deal with the electrical properties of lithium. We discuss the ultimate limit for the measure of the static electric polarizability of lithium by atomic interferometry. Then, we discuss how one could measure the possible charge of the lithium atom. We conclude that an optically cooled and collimated atom beam would improve precision. (author)

  6. Fracture source

    Directory of Open Access Journals (Sweden)

    2003-07-01

    Full Text Available The fracture properties of many different types of fibers are covered in a timely new book that will prove to be a tremendous source of information and references for researchers in the wide and diverse field of fibers and composites, says Bill Clegg.

  7. Atomic force microscopy of atomic-scale ledges and etch pits formed during dissolution of quartz

    Science.gov (United States)

    Gratz, A. J.; Manne, S.; Hansma, P. K.

    1991-01-01

    The processes involved in the dissolution and growth of crystals are closely related. Atomic force microscopy (AFM) of faceted pits (called negative crystals) formed during quartz dissolution reveals subtle details of these underlying physical mechanisms for silicates. In imaging these surfaces, the AFM detected ledges less than 1 nm high that were spaced 10 to 90 nm apart. A dislocation pit, invisible to optical and scanning electron microscopy measurements and serving as a ledge source, was also imaged. These observations confirm the applicability of ledge-motion models to dissolution and growth of silicates; coupled with measurements of dissolution rate on facets, these methods provide a powerful tool for probing mineral surface kinetics.

  8. Atom-by-Atom Construction of a Quantum Device.

    Science.gov (United States)

    Petta, Jason R

    2017-03-28

    Scanning tunneling microscopes (STMs) are conventionally used to probe surfaces with atomic resolution. Recent advances in STM include tunneling from spin-polarized and superconducting tips, time-domain spectroscopy, and the fabrication of atomically precise Si nanoelectronics. In this issue of ACS Nano, Tettamanzi et al. probe a single-atom transistor in silicon, fabricated using the precision of a STM, at microwave frequencies. While previous studies have probed such devices in the MHz regime, Tettamanzi et al. probe a STM-fabricated device at GHz frequencies, which enables excited-state spectroscopy and measurements of the excited-state lifetime. The success of this experiment will enable future work on quantum control, where the wave function must be controlled on a time scale that is much shorter than the decoherence time. We review two major approaches that are being pursued to develop spin-based quantum computers and highlight some recent progress in the atom-by-atom fabrication of donor-based devices in silicon. Recent advances in STM lithography may enable practical bottom-up construction of large-scale quantum devices.

  9. Radiation Tolerant Low Power Precision Time Source Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The availability of small, low power atomic clocks is now a reality for ground-based and airborne navigation systems. Kernco's Low Power Precision Time Source...

  10. Quantum Phases of Atom-Molecule Mixtures of Fermionic Atoms

    Science.gov (United States)

    Lopez, Nicolas; Tsai, Shan-Wen

    2009-11-01

    Cold atom experiments have observed atom-molecule mixtures by tuning the interactions between particles.footnotetextM.L. Olsen, J. D. Perreault, T. D. Cumby, and D. S. Jin, Phys. Rev. A 80, 030701(R) (2009) We study many particle interactions by examaning a simple model that describes the destruction of fermionic atom pairs to form single bosonic molecules and vice versa. A set of functional Renomalization Group equationsfootnotetextR. Shankar, Rev. Mod. Phys., Vol 66 No. 1, January 1994^,footnotetextS.W. Tsai, A.H. Castro Neto, R. Shankar, D.K. Campbell, Phys. Rev. B 72, 054531 (2005) describing these processes are set up and solved numerically. The Self Energy of the fermions are attained as a function of frequency and we search for frequency dependent instabilities that could denote a transition from a disordered liquid to a BCS phase. (Financial support from NSF DMR-084781 and UC-Lab Fees Research Program.)

  11. Atomic-cascade experiment with detection of the recoil atom

    Energy Technology Data Exchange (ETDEWEB)

    Huelga, S.F. (Dept. de Fisica, Univ. de Oviedo (Spain)); Ferrero, M. (Dept. de Fisica, Univ. de Oviedo (Spain)); Santos, E. (Dept. de Fisica Moderna, Univ. de Cantabria (Spain))

    1994-07-20

    Bell's inequalities cannot be violated in atomic-cascade experiments, even with ideal apparatus, due to the three-body character of the atomic decay. Here we propose a new experiment that would block this loophole by means of a suitable selection of an ensemble of photon pairs. A threshold value for the quantum efficiency is found which may allow the discrimination between quantum mechanics and local-hidden-variables theories. Experimental requirements for performing such a test are discussed. (orig.).

  12. Emission of fast non-Maxwellian hydrogen atoms in low-density laboratory plasma

    Science.gov (United States)

    Brandt, Christian; Marchuk, Oleksandr; Pospieszczyk, Albrecht; Dickheuer, Sven

    2017-03-01

    The source of strong and broad emission of the Balmer-α line in mixed plasmas of hydrogen (or deuterium) and noble gases in front of metallic surfaces is a subject of controversial discussion of many plasma types. In this work the excitation source of the Balmer lines is investigated by means of optical emission spectroscopy in the plasma device PSI-2. Neutral fast non-Maxwellian hydrogen atoms are produced by acceleration of hydrogen ions towards an electrode immersed into the plasma. By variation of the electrode potential the energy of ions and in turn of reflected fast atoms can be varied in the range of 40-300 eV. The fast atoms in front of the electrode are observed simultaneously by an Echelle spectrometer (0.001 nm/channel) and by an imaging spectrometer (0.01 nm/channel) up to few cm in the plasma. Intense excitation channels of the Balmer lines are observed when hydrogen is mixed with argon or with krypton. Especially in Ar-H and Ar-D mixed plasmas the emission of fast hydrogen atoms is very strong. Intermixing hydrogen with other noble gases (He, Ne or Xe) one observes the same effect however the emission is one order of magnitude less compared to Kr-H or Kr-D plasmas. It is shown, that the key process, impacting this emission, is the binary collision between the fast neutral hydrogen atom and the noble gas atom. Two possible sources of excitation are discussed in details: one is the excitation of hydrogen atoms by argon atoms in the ground state and the second one is the process of the so-called excitation transfer between the metastable states of noble gases and hydrogen. In the latter case the atomic data for excitation of Balmer lines are still not available in literature. Further experimental investigations are required to conclude on the source process of fast atom emission.

  13. Near-Heisenberg-limited atomic clocks in the presence of decoherence.

    Science.gov (United States)

    Borregaard, J; Sørensen, A S

    2013-08-30

    The ultimate stability of atomic clocks is limited by the quantum noise of the atoms. To reduce this noise it has been suggested to use entangled atomic ensembles with reduced atomic noise. Potentially this can push the stability all the way to the limit allowed by the Heisenberg uncertainty relation, which is denoted the Heisenberg limit. In practice, however, entangled states are often more prone to decoherence, which may prevent reaching this performance. Here we present an adaptive measurement protocol that in the presence of a realistic source of decoherence enables us to get near-Heisenberg-limited stability of atomic clocks using entangled atoms. The protocol may thus realize the full potential of entanglement for quantum metrology despite the detrimental influence of decoherence.

  14. Modeling non local thermodynamic equilibrium plasma using the Flexible Atomic Code data

    CERN Document Server

    Han, Bo; Salzmann, David; Zhao, Gang

    2015-01-01

    We present a new code, RCF("Radiative-Collisional code based on FAC"), which is used to simulate steady-state plasmas under non local thermodynamic equilibrium condition, especially photoinization dominated plasmas. RCF takes almost all of the radiative and collisional atomic processes into rate equation to interpret the plasmas systematically. The Flexible Atomic Code (FAC) supplies all the atomic data RCF needed, which insures calculating completeness and consistency of atomic data. With four input parameters relating to the radiation source and target plasma, RCF calculates the population of levels and charge states, as well as potentially emission spectrum. In preliminary application, RCF successfully reproduces the results of a photoionization experiment with reliable atomic data. The effects of the most important atomic processes on the charge state distribution are also discussed.

  15. Continuous Cold-atom Inertial Sensor with $1\\ \\text{nrad.s}^{-1}$ Rotation Stability

    CERN Document Server

    Dutta, I; Fang, B; Venon, B; Alzar, C L Garrido; Geiger, R; Landragin, A

    2016-01-01

    We report the operation of a cold-atom inertial sensor which continuously captures the rotation signal. Using a joint interrogation scheme, where we simultaneously prepare a cold-atom source and operate an atom interferometer (AI) enables us to eliminate the dead times. We show that such continuous operation improves the short-term sensitivity of AIs, and demonstrate a rotation sensitivity of $100\\ \\text{nrad.s}^{-1}.\\text{Hz}^{-1/2}$ in a cold-atom gyroscope of $11 \\ \\text{cm}^2$ Sagnac area. We also demonstrate a rotation stability of $1 \\ \\text{nrad.s}^{-1}$ at $10^4$ s of integration time, which establishes the record for atomic gyroscopes. The continuous operation of cold-atom inertial sensors will enable to benefit from the full sensitivity potential of large area AIs, determined by the quantum noise limit.

  16. Direct observation of chiral currents and magnetic reflection in atomic flux lattices

    CERN Document Server

    An, Fangzhao Alex; Gadway, Bryce

    2016-01-01

    The prospect of studying topologically nontrivial phases with the precision and control of atomic physics has driven the development of many techniques for engineering artificial magnetic fields and spin-orbit interactions in atomic gases. Recently, the idea of engineering nontrivial topology through the use of discrete internal (or external) atomic states as effective "artificial dimensions" has garnered attraction for its versatility and promise of immunity from sources of heating. Here, we directly engineer tunable artificial gauge fields through the local control of tunneling phases in an effectively two-dimensional manifold of discrete atomic momentum states. We demonstrate the ability to engineer homogeneous artificial gauge fields of arbitrary value, directly imaging the site-resolved dynamics of induced chiral currents. We furthermore engineer the first inhomogeneous artificial gauge fields for cold atoms, enabling the observation of magnetic reflection of atoms incident upon a step-like variation of ...

  17. Effects of atomic hydrogen and deuterium exposure on high polarization GaAs photocathodes

    Energy Technology Data Exchange (ETDEWEB)

    M. Baylac; P. Adderley; J. Brittian; J. Clark; T. Day; J. Grames; J. Hansknecht; M. Poelker; M. Stutzman; A. T. Wu; A. S. Terekhov

    2005-12-01

    Strained-layer GaAs and strained-superlattice GaAs photocathodes are used at Jefferson Laboratory to create high average current beams of highly spin-polarized electrons. High electron yield, or quantum efficiency (QE), is obtained only when the photocathode surface is atomically clean. For years, exposure to atomic hydrogen or deuterium has been the photocathode cleaning technique employed at Jefferson Laboratory. This work demonstrates that atomic hydrogen cleaning is not necessary when precautions are taken to ensure that clean photocathode material from the vendor is not inadvertently dirtied while samples are prepared for installation inside photoemission guns. Moreover, this work demonstrates that QE and beam polarization can be significantly reduced when clean high-polarization photocathode material is exposed to atomic hydrogen from an rf dissociator-style atomic hydrogen source. Surface analysis provides some insight into the mechanisms that degrade QE and polarization due to atomic hydrogen cleaning.

  18. Continuous Cold-Atom Inertial Sensor with 1  nrad/sec Rotation Stability.

    Science.gov (United States)

    Dutta, I; Savoie, D; Fang, B; Venon, B; Garrido Alzar, C L; Geiger, R; Landragin, A

    2016-05-06

    We report the operation of a cold-atom inertial sensor which continuously captures the rotation signal. Using a joint interrogation scheme, where we simultaneously prepare a cold-atom source and operate an atom interferometer (AI), enables us to eliminate the dead times. We show that such continuous operation improves the short-term sensitivity of AIs, and demonstrate a rotation sensitivity of 100  nrad/sec/sqrt[Hz] in a cold-atom gyroscope of 11  cm^{2} Sagnac area. We also demonstrate a rotation stability of 1  nrad/sec at 10^{4}  sec of integration time, which represents the state of the art for atomic gyroscopes. The continuous operation of cold-atom inertial sensors will lead to large area AIs at their full sensitivity potential, determined by the quantum noise limit.

  19. Single mode quadrature entangled light from room temperature atomic vapour

    CERN Document Server

    Wasilewski, W; Jensen, K; Madsen, L S; Krauter, H; Polzik, E S

    2009-01-01

    We analyse a novel squeezing and entangling mechanism which is due to correlated Stokes and anti-Stokes photon forward scattering in a multi-level atom vapour. Following the proposal we present an experimental demonstration of 3.5 dB pulsed frequency nondegenerate squeezed (quadrature entangled) state of light using room temperature caesium vapour. The source is very robust and requires only a few milliwatts of laser power. The squeezed state is generated in the same spatial mode as the local oscillator and in a single temporal mode. The two entangled modes are separated by twice the Zeeman frequency of the vapour which can be widely tuned. The narrow-band squeezed light generated near an atomic resonance can be directly used for atom-based quantum information protocols. Its single temporal mode characteristics make it a promising resource for quantum information processing.

  20. Cooperative scattering and radiation pressure force in dense atomic clouds

    Energy Technology Data Exchange (ETDEWEB)

    Bachelard, R. [University of Nova Gorica, School of Applied Sciences, Vipavska 11c SI-5270 Ajdovscina (Slovenia); Piovella, N. [Dipartimento di Fisica, Universita Degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy); Courteille, Ph. W. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, 13560-970 Sao Carlos, SP (Brazil)

    2011-07-15

    Atomic clouds prepared in ''timed Dicke'' states, i.e. states where the phase of the oscillating atomic dipole moments linearly varies along one direction of space, are efficient sources of superradiant light emission [Scully et al., Phys. Rev. Lett. 96, 010501 (2006)]. Here, we show that, in contrast to previous assertions, timed Dicke states are not the states automatically generated by incident laser light. In reality, the atoms act back on the driving field because of the finite refraction of the cloud. This leads to nonuniform phase shifts, which, at higher optical densities, dramatically alter the cooperative scattering properties, as we show by explicit calculation of macroscopic observables, such as the radiation pressure force.

  1. Biological atomism and cell theory.

    Science.gov (United States)

    Nicholson, Daniel J

    2010-09-01

    Biological atomism postulates that all life is composed of elementary and indivisible vital units. The activity of a living organism is thus conceived as the result of the activities and interactions of its elementary constituents, each of which individually already exhibits all the attributes proper to life. This paper surveys some of the key episodes in the history of biological atomism, and situates cell theory within this tradition. The atomistic foundations of cell theory are subsequently dissected and discussed, together with the theory's conceptual development and eventual consolidation. This paper then examines the major criticisms that have been waged against cell theory, and argues that these too can be interpreted through the prism of biological atomism as attempts to relocate the true biological atom away from the cell to a level of organization above or below it. Overall, biological atomism provides a useful perspective through which to examine the history and philosophy of cell theory, and it also opens up a new way of thinking about the epistemic decomposition of living organisms that significantly departs from the physicochemical reductionism of mechanistic biology.

  2. Light element opacities from ATOMIC

    Science.gov (United States)

    Colgan, J.; Kilcrease, D. P.; Magee, N. H.; Armstrong, G. S. J.; Abdallah, J.; Sherrill, M. E.; Fontes, C. J.; Zhang, H. L.; Hakel, P.

    2013-06-01

    We present new calculations of local-thermodynamic-equilibrium (LTE) light element opacities from the Los Alamos ATOMIC code. ATOMIC is a multi-purpose code that can generate LTE or non-LTE quantities of interest at various levels of approximation. A program of work is currently underway to compute new LTE opacity data for all elements H through Zn. New opacity tables for H through Ne are complete, and a new Fe opacity table will be available soon. Our calculations, which include fine-structure detail, represent a systematic improvement over previous Los Alamos opacity calculations using the LEDCOP legacy code. Our opacity calculations incorporate atomic structure data computed from the CATS code, which is based on Cowan's atomic structure codes, and photoionization cross section data computed from the Los Alamos ionization code GIPPER. We make use of a new equation-of-state (EOS) model based on the chemical picture. ATOMIC incorporates some physics packages from LEDCOP and also includes additional physical processes, such as improved free-free cross sections and additional scattering mechanisms. In this report, we briefly discuss the physics improvements included in our new opacity calculations and present comparisons of our new opacities with other work for C, O, and Fe at selected conditions.

  3. Efficient transfer of francium atoms

    Science.gov (United States)

    Aubin, Seth; Behr, John; Gorelov, Alexander; Pearson, Matt; Tandecki, Michael; Collister, Robert; Gwinner, Gerald; Shiells, Kyle; Gomez, Eduardo; Orozco, Luis; Zhang, Jiehang; Zhao, Yanting; FrPNC Collaboration

    2016-05-01

    We report on the progress of the FrPNC collaboration towards Parity Non Conservation Measurements (PNC) using francium atoms at the TRIUMF accelerator. We demonstrate efficient transfer (higher than 40%) to the science vacuum chamber where the PNC measurements will be performed. The transfer uses a downward resonant push beam from the high-efficiency capture magneto optical trap (MOT) towards the science chamber where the atoms are recaptured in a second MOT. The transfer is very robust with respect to variations in the parameters (laser power, detuning, alignment, etc.). We accumulate a growing number of atoms at each transfer pulse (limited by the lifetime of the MOT) since the push beam does not eliminate the atoms already trapped in the science MOT. The number of atoms in the science MOT is on track to meet the requirements for competitive PNC measurements when high francium rates (previously demonstrated) are delivered to our apparatus. The catcher/neutralizer for the ion beam has been tested reliably to 100,000 heating/motion cycles. We present initial tests on the direct microwave excitation of the ground hyperfine transition at 45 GHz. Support from NSERC and NRC from Canada, NSF and Fulbright from USA, and CONACYT from Mexico.

  4. Laser spectroscopy of atomic radium

    Energy Technology Data Exchange (ETDEWEB)

    Groot, Alexander; Jungmann, Klaus; Santra, Bodhaditya; Willmann, Lorenz; Wilschut, Hans W. [KVI, University of Groningen (Netherlands)

    2009-07-01

    The heavy alkaline earth elements radium (Ra) offers a unique sensitivity to a parity and time reversal violating permanent electric dipole moments (EDM). In particular, Ra exhibits the largest known atomic enhancements factors for EDMs. The intrinsic sensitivity arises from the specific atomic and nuclear structure of Ra. All Ra isotopes with nuclear spin I are radioactive. The lifetimes are shorter than 15 d. Several Ra isotopes are available at the TRI{mu}P facility at KVI. For the exploitation of the sensitivity Ra atoms have to be collected in a neutral atom trap. The main laser cooling is done on the strong {sup 1}S{sub 0}-{sup 1}P{sub 1} transition at 482.7 nm, similar to the laser cooling and trapping of the chemical homologue barium. Laser spectroscopy of the strong {sup 1}S{sub 0}-{sup 1}P{sub 1} transitions is presented. The light at this wavelength is provided by frequency doubling of a Ti:sapphire laser in a KNbO{sub 3} crystal. Of particular interest is the decay branching of the excited state to the metastable D-states. Such measurements are indispensable input for current atomic structure calculations, which are necessary for the analysis of a EDM measurement using Ra.

  5. Atomic memory access hardware implementations

    Science.gov (United States)

    Ahn, Jung Ho; Erez, Mattan; Dally, William J

    2015-02-17

    Atomic memory access requests are handled using a variety of systems and methods. According to one example method, a data-processing circuit having an address-request generator that issues requests to a common memory implements a method of processing the requests using a memory-access intervention circuit coupled between the generator and the common memory. The method identifies a current atomic-memory access request from a plurality of memory access requests. A data set is stored that corresponds to the current atomic-memory access request in a data storage circuit within the intervention circuit. It is determined whether the current atomic-memory access request corresponds to at least one previously-stored atomic-memory access request. In response to determining correspondence, the current request is implemented by retrieving data from the common memory. The data is modified in response to the current request and at least one other access request in the memory-access intervention circuit.

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

    CERN Document Server

    Chanu, Sapam Ranjita; Natarajan, Vasant

    2016-01-01

    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.

  7. Chameleon dark energy and atom interferometry

    Science.gov (United States)

    Elder, Benjamin; Khoury, Justin; Haslinger, Philipp; Jaffe, Matt; Müller, Holger; Hamilton, Paul

    2016-08-01

    Atom interferometry experiments are searching for evidence of chameleon scalar fields with ever-increasing precision. As experiments become more precise, so too must theoretical predictions. Previous work has made numerous approximations to simplify the calculation, which in general requires solving a three-dimensional nonlinear partial differential equation. This paper calculates the chameleonic force using a numerical relaxation scheme on a uniform grid. This technique is more general than previous work, which assumed spherical symmetry to reduce the partial differential equation to a one-dimensional ordinary differential equation. We examine the effects of approximations made in previous efforts on this subject and calculate the chameleonic force in a setup that closely mimics the recent experiment of Hamilton et al. Specifically, we simulate the vacuum chamber as a cylinder with dimensions matching those of the experiment, taking into account the backreaction of the source mass, its offset from the center, and the effects of the chamber walls. Remarkably, the acceleration on a test atomic particle is found to differ by only 20% from the approximate analytical treatment. These results allow us to place rigorous constraints on the parameter space of chameleon field theories, although ultimately the constraint we find is the same as the one we reported in Hamilton et al. because we had slightly underestimated the size of the vacuum chamber. This computational technique will continue to be useful as experiments become even more precise and will also be a valuable tool in optimizing future searches for chameleon fields and related theories.

  8. Innershell Photoionization Studies of Neutral Atomic Nitrogen

    CERN Document Server

    Stolte, W C; Lindle, D W; Sant'Anna, M M; Savin, D W

    2014-01-01

    Innershell ionization of a $1s$ electron by either photons or electrons is important for X-ray photoionized objects such as active galactic nuclei and electron-ionized sources such as supernova remnants. Modeling and interpreting observations of such objects requires accurate predictions for the charge state distribution (CSD) which results as the $1s$-hole system stabilizes. Due to the complexity of the complete stabilization process, few modern calculations exist and the community currently relies on 40-year-old atomic data. Here, we present a combined experimental and theoretical study for innershell photoionization of neutral atomic nitrogen for photon energies of $403-475$~eV. Results are reported for the total ion yield cross section, for the branching ratios for formation of N$^+$, N$^{2+}$, and N$^{3+}$, and for the average charge state. We find significant differences when comparing to the data currently available to the astrophysics community. For example, while the branching ratio to N$^{2+}$ is so...

  9. Trapping fermionic and bosonic helium atoms

    NARCIS (Netherlands)

    Stas, R.J.W.

    2005-01-01

    This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof

  10. Comparison of atom interferometers and light interferometers as space-based gravitational wave detectors.

    Science.gov (United States)

    Baker, John G; Thorpe, J I

    2012-05-25

    We consider a class of proposed gravitational-wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, noninertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g., multiple-arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and, in principle, favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  11. Comparison of Atom Interferometers and Light Interferometers as Space-Based Gravitational Wave Detectors

    Science.gov (United States)

    Baker, John G.

    2012-01-01

    We consider a class of proposed gravitational wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, non-inertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g. multiple arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

  12. Chameleon Dark Energy and Atom Interferometry

    CERN Document Server

    Elder, Benjamin; Haslinger, Philipp; Jaffe, Matt; Müller, Holger; Hamilton, Paul

    2016-01-01

    Atom interferometry experiments are searching for evidence of chameleon scalar fields with ever-increasing precision. As experiments become more precise, so too must theoretical predictions. Previous work has made numerous approximations to simplify the calculation, which in general requires solving a 3-dimensional nonlinear partial differential equation (PDE). In this paper, we introduce a new technique for calculating the chameleonic force, using a numerical relaxation scheme on a uniform grid. This technique is more general than previous work, which assumed spherical symmetry to reduce the PDE to a 1-dimensional ordinary differential equation (ODE). We examine the effects of approximations made in previous efforts on this subject, and calculate the chameleonic force in a set-up that closely mimics the recent experiment of Hamilton et al. Specifically, we simulate the vacuum chamber as a cylinder with dimensions matching those of the experiment, taking into account the backreaction of the source mass, its o...

  13. Conductivity of an atomically defined metallic interface.

    Science.gov (United States)

    Oliver, David J; Maassen, Jesse; El Ouali, Mehdi; Paul, William; Hagedorn, Till; Miyahara, Yoichi; Qi, Yue; Guo, Hong; Grütter, Peter

    2012-11-20

    A mechanically formed electrical nanocontact between gold and tungsten is a prototypical junction between metals with dissimilar electronic structure. Through atomically characterized nanoindentation experiments and first-principles quantum transport calculations, we find that the ballistic conduction across this intermetallic interface is drastically reduced because of the fundamental mismatch between s wave-like modes of electron conduction in the gold and d wave-like modes in the tungsten. The mechanical formation of the junction introduces defects and disorder, which act as an additional source of conduction losses and increase junction resistance by up to an order of magnitude. These findings apply to nanoelectronics and semiconductor device design. The technique that we use is very broadly applicable to molecular electronics, nanoscale contact mechanics, and scanning tunneling microscopy.

  14. Surface Acoustic Wave Atomizer and Electrostatic Deposition

    Science.gov (United States)

    Yamagata, Yutaka

    A new methodology for fabricating thin film or micro patters of organic/bio material using surface acoustic wave (SAW) atomizer and electrostatic deposition is proposed and characteristics of atomization techniques are discussed in terms of drop size and atomization speed. Various types of SAW atomizer are compared with electrospray and conventional ultrasonic atomizers. It has been proved that SAW atomizers generate drops as small as electrospray and have very fast atomization speed. This technique is applied to fabrication of micro patterns of proteins. According to the result of immunoassay, the specific activity of immunoglobulin was preserved after deposition process.

  15. Response functions of atom gravimeters

    CERN Document Server

    Nagornyi, V D

    2012-01-01

    Atom gravimeters are equivalent to non-multi-level corner-cube gravimeters in translating the gravity signal into the measurement result. This enables description of atom gravimeters as LTI systems. The system's impulse responses by acceleration, velocity, and displacement are found to have the shape of triangle, meander, and the Dirac comb resp. The effects of inhomogeneous gravity field are studied for constant and linear vertical gradients and self-attraction of the instrument. For the constant gradient the effective measurement height is below the top of the trajectory at 1/6 and 7/24 of its length for the fountain and the release types of the instruments resp. The analysis is expanded to the gravimeters implementing the Bloch oscillations at the apex of the trajectory. In filtering the vibrations these instruments are equivalent to the first-order low-pass filters, while other atom gravimeters are equivalent to the second-order low-pass filters.

  16. Cavity QED with many atoms

    CERN Document Server

    Martini, U

    1999-01-01

    We have studied the interaction of an arbitrary number Z of atoms with a quantized damped resonator mode. In order to reduce the dimension of the system we employed a symmetrized density operator description. These density operators are analogous to angular momentum eigenstates which are usually referred to as Dicke states.In this symmetric basis the dimension of the atomic system is only 1/6(Z+1)(Z+2)(Z+3) in contrast to 4 sup Z without symmetrization. We have shown that the symmetry is not broken by spontaneous emission. A simple analytical expression for the matrix elements of the complete Liouville operator with respect to the Dicke states was found. Using these results we are able to study the interaction of the atoms with a resonator mode without any further approximations.

  17. Atomic horror deal; Atom-Deal des Grauens

    Energy Technology Data Exchange (ETDEWEB)

    May, Hanne

    2010-10-15

    The German government is opting out of the decided nuclear phaseout and will ensure good profits for operators of nuclear power plants. Complex contracts and the disregard of safety regulations will result in a continued atomic energy policy, even beyond the next elections and in disrespect of democratic procedures and bodies. (orig.)

  18. The Atom and the Ocean, Understanding the Atom Series.

    Science.gov (United States)

    Hull, E. W. Seabrook

    Included is a brief description of the characteristics of the ocean, its role as a resource for food and minerals, its composition and its interactions with land and air. The role of atomic physics in oceanographic exploration is illustrated by the use of nuclear reactors to power surface and submarine research vessels and the design and use of…

  19. Atomically resolved graphitic surfaces in air by atomic force microscopy.

    Science.gov (United States)

    Wastl, Daniel S; Weymouth, Alfred J; Giessibl, Franz J

    2014-05-27

    Imaging at the atomic scale using atomic force microscopy in biocompatible environments is an ongoing challenge. We demonstrate atomic resolution of graphite and hydrogen-intercalated graphene on SiC in air. The main challenges arise from the overall surface cleanliness and the water layers which form on almost all surfaces. To further investigate the influence of the water layers, we compare data taken with a hydrophilic bulk-silicon tip to a hydrophobic bulk-sapphire tip. While atomic resolution can be achieved with both tip materials at moderate interaction forces, there are strong differences in force versus distance spectra which relate to the water layers on the tips and samples. Imaging at very low tip-sample interaction forces results in the observation of large terraces of a naturally occurring stripe structure on the hydrogen-intercalated graphene. This structure has been previously reported on graphitic surfaces that are not covered with disordered adsorbates in ambient conditions (i.e., on graphite and bilayer graphene on SiC, but not on monolayer graphene on SiC). Both these observations indicate that hydrogen-intercalated graphene is close to an ideal graphene sample in ambient environments.

  20. Super-Coulombic atom-atom interactions in hyperbolic media

    CERN Document Server

    Cortes, Cristian L

    2016-01-01

    Dipole-dipole interactions which govern phenomena like cooperative Lamb shifts, superradiant decay rates, Van der Waals forces, as well as resonance energy transfer rates are conventionally limited to the Coulombic near-field. Here, we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic (QED) interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a Super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media and propose practical implementations with phonon-polaritonic hexagonal boron nitride in the infrared spectral range and plasmonic super-lattice structures in the visible range. Our work paves the way for the control of cold atoms in hyperbolic media and the study of many-body atomic states where optical phonons mediate qua...

  1. Optimized absorption imaging of mesoscopic atomic clouds

    Science.gov (United States)

    Muessel, Wolfgang; Strobel, Helmut; Joos, Maxime; Nicklas, Eike; Stroescu, Ion; Tomkovič, Jiří; Hume, David B.; Oberthaler, Markus K.

    2013-10-01

    We report on the optimization of high-intensity absorption imaging for small Bose-Einstein condensates. The imaging calibration exploits the linear scaling of the quantum projection noise with the mean number of atoms for a coherent spin state. After optimization for atomic clouds containing up to 300 atoms, we find an atom number resolution of atoms, mainly limited by photon shot noise and radiation pressure.

  2. Microfabrication of gold wires for atom guides

    OpenAIRE

    Kukharenka, Elena; Moktadir, Zak; Kraft, Michael; Abdelsalam, M.E.; Bagnall, Darren; Vale, C.; Jones, M. P. A.; Hinds, E.A.

    2004-01-01

    Miniaturised atom optics is a new field allowing the control of cold atoms in microscopic magnetic traps and waveguides. Using microstructures (hereafter referred to as atom chips), the control of cold atoms on the micrometer scale becomes possible. Applications range from integrated atom interferometers to the realisation of quantum gates. The implementation of such structures requires high magnetic field gradients.\\ud The motivation of this work was to develop a suitable fabrication process...

  3. Charge Qubit-Atom Hybrid

    CERN Document Server

    Yu, Deshui; Hufnagel, C; Kwek, L C; Amico, Luigi; Dumke, R

    2016-01-01

    We investigate a novel hybrid system of a superconducting charge qubit interacting directly with a single neutral atom via electric dipole coupling. Interfacing of the macroscopic superconducting circuit with the microscopic atomic system is accomplished by varying the gate capacitance of the charge qubit. To achieve strong interaction, we employ two Rydberg states with an electric-dipole-allowed transition, which alters the polarizability of the dielectric medium of the gate capacitor. Sweeping the gate voltage with different rates leads to a precise control of hybrid quantum states. Furthermore, we show a possible implementation of a universal two-qubit gate.

  4. Atoms, Radiation, and Radiation Protection

    CERN Document Server

    Turner, James E

    2007-01-01

    Atoms, Radiation, and Radiation Protection offers professionals and advanced students a comprehensive coverage of the major concepts that underlie the origins and transport of ionizing radiation in matter. Understanding atomic structure and the physical mechanisms of radiation interactions is the foundation on which much of the current practice of radiological health protection is based. The work covers the detection and measurement of radiation and the statistical interpretation of the data. The procedures that are used to protect man and the environment from the potential harmful effects of

  5. Atomic Manipulation on Metal Surfaces

    Science.gov (United States)

    Ternes, Markus; Lutz, Christopher P.; Heinrich, Andreas J.

    Half a century ago, Nobel Laureate Richard Feynman asked in a now-famous lecture what would happen if we could precisely position individual atoms at will [R.P. Feynman, Eng. Sci. 23, 22 (1960)]. This dream became a reality some 30 years later when Eigler and Schweizer were the first to position individual Xe atoms at will with the probe tip of a low-temperature scanning tunneling microscope (STM) on a Ni surface [D.M. Eigler, E.K. Schweizer, Nature 344, 524 (1990)].

  6. Spatial confinement of muonium atoms

    Science.gov (United States)

    Khaw, K. S.; Antognini, A.; Prokscha, T.; Kirch, K.; Liszkay, L.; Salman, Z.; Crivelli, P.

    2016-08-01

    We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into a vacuum from mesoporous silica reflects between two SiO2 confining surfaces separated by 1 mm. From the data, one can extract that the reflection probability on the confining surfaces kept at 100 K is about 90% and the reflection process is well described by a cosine law. This technique enables new experiments with this exotic atomic system and is a very important step towards a measurement of the 1 S -2 S transition frequency using continuous-wave laser spectroscopy.

  7. Spatial confinement of muonium atoms

    CERN Document Server

    Khaw, K S; Prokscha, T; Kirch, K; Liszkay, L; Salman, Z; Crivelli, P

    2016-01-01

    We report the achievement of spatial confinement of muonium atoms (the bound state of a positive muon and an electron). Muonium emitted into vacuum from mesoporous silica is forced to bounce back and forth between two SiO$_2$ confining surfaces separated by 1 mm. From the data, one can extract that the reflection on the confining surfaces is well described by a cosine law. This technique opens up a way to perform new experiments with this exotic atomic system and is a very important step towards a measurement of the 1S-2S transition frequency using continuous wave laser spectroscopy.

  8. Sub-Angstrom Atomic-Resolution Imaging of Heavy Atoms to Light Atoms

    Energy Technology Data Exchange (ETDEWEB)

    O' Keefe, Michael A.; Shao-Horn, Yang

    2003-05-23

    Three decades ago John Cowley and his group at ASU achieved high-resolution electron microscope images showing the crystal unit cell contents at better than 4Angstrom resolution. Over the years, this achievement has inspired improvements in resolution that have enabled researchers to pinpoint the positions of heavy atom columns within the cell. More recently, this ability has been extended to light atoms as resolution has improved. Sub-Angstrom resolution has enabled researchers to image the columns of light atoms (carbon, oxygen and nitrogen) that are present in many complex structures. By using sub-Angstrom focal-series reconstruction of the specimen exit surface wave to image columns of cobalt, oxygen, and lithium atoms in a transition metal oxide structure commonly used as positive electrodes in lithium rechargeable batteries, we show that the range of detectable light atoms extends to lithium. HRTEM at sub-Angstrom resolution will provide the essential role of experimental verification for the emergent nanotech revolution. Our results foreshadow those to be expected from next-generation TEMs with Cs-corrected lenses and monochromated electron beams.

  9. Source rock

    OpenAIRE

    Abubakr F. Makky; Mohamed I. El Sayed; Ahmed S. Abu El-Ata; Ibrahim M. Abd El-Gaied; Mohamed I. Abdel-Fattah; Zakaria M. Abd-Allah

    2014-01-01

    West Beni Suef Concession is located at the western part of Beni Suef Basin which is a relatively under-explored basin and lies about 150 km south of Cairo. The major goal of this study is to evaluate the source rock by using different techniques as Rock-Eval pyrolysis, Vitrinite reflectance (%Ro), and well log data of some Cretaceous sequences including Abu Roash (E, F and G members), Kharita and Betty formations. The BasinMod 1D program is used in this study to construct the burial history ...

  10. Ion microscopy based on laser-cooled cesium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Viteau, M.; Reveillard, M.; Kime, L.; Rasser, B.; Sudraud, P. [Orsay Physics, TESCAN Orsay, 95 Avenue des Monts Auréliens – ZA Saint-Charles – 13710 Fuveau (France); Bruneau, Y.; Khalili, G.; Pillet, P.; Comparat, D. [Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Bât. 505, 91405 Orsay (France); Guerri, I. [Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Fioretti, A., E-mail: andrea.fioretti@ino.it [Istituto Nazionale di Ottica, INO-CNR, U.O.S. ”Adriano Gozzini”, via Moruzzi 1, 56124 Pisa (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, CNISM, Sezione di Pisa, 56127 Pisa (Italy); Ciampini, D.; Allegrini, M.; Fuso, F. [Dipartimento di Fisica, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Istituto Nazionale di Ottica, INO-CNR, U.O.S. ”Adriano Gozzini”, via Moruzzi 1, 56124 Pisa (Italy); Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, CNISM, Sezione di Pisa, 56127 Pisa (Italy)

    2016-05-15

    We demonstrate a prototype of a Focused Ion Beam machine based on the ionization of a laser-cooled cesium beam and adapted for imaging and modifying different surfaces in the few-tens nanometer range. Efficient atomic ionization is obtained by laser promoting ground-state atoms into a target excited Rydberg state, then field-ionizing them in an electric field gradient. The method allows obtaining ion currents up to 130 pA. Comparison with the standard direct photo-ionization of the atomic beam shows, in our conditions, a 40-times larger ion yield. Preliminary imaging results at ion energies in the 1–5 keV range are obtained with a resolution around 40 nm, in the present version of the prototype. Our ion beam is expected to be extremely monochromatic, with an energy spread of the order of the eV, offering great prospects for lithography, imaging and surface analysis. - Highlights: • We realize a Focused Ion Beam with an ionic source based on laser cooled cesium atoms. • Ionization involves excitation of the laser cooled atoms to Rydberg states. • We use the cesium FIB system to image different materials. • We use the cesium FIB to produce permanent modifications on surfaces. • In the present configuration, the focused probe size of the cesium FIB prototype is about 300 nm for beam energies in the 2–5 keV range.

  11. Prospects of Optical Single Atom Detection for Nuclear Astrophysics

    Science.gov (United States)

    Singh, Jaideep

    2015-10-01

    We will discuss the prospects of optically detecting single atoms captured in a cryogenic thin film of a noble gas such as neon. This proposed detection scheme, when coupled with a recoil separator, could be used to measure rare nuclear reactions relevant for nuclear astrophysics. In particular, we will focus on the 22Ne(α, n)25Mg reaction, which is an important source of neutrons for the s-process. Noble gas solids are an attractive medium because they are optically transparent and provide efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Atoms embedded inside of noble gas solids have a fluorescence spectrum that is often significantly shifted from its absorption spectrum. This makes possible the detection of individual fluorescence photons against a background of intense excitation light, which can be suppressed using the appropriate optical filters. We will report on our efforts to optically detect single Yb atoms in solid Ne. Yb is an ideal candidate for initial studies because it emits a strong green fluorescence when excited by blue light and it has an atomic structure that very closely resembles that of Mg. This work is supported by funds from Michigan State University.

  12. Photonic, Electronic and Atomic Collisions

    Science.gov (United States)

    Fainstein, Pablo D.; Lima, Marco Aurelio P.; Miraglia, Jorge E.; Montenegro, Eduardo C.; Rivarola, Roberto D.

    2006-11-01

    Plenary. Electron collisions - past, present and future / J. W. McConkey. Collisions of slow highly charged ions with surfaces / J. Burgdörfer ... [et al.]. Atomic collisions studied with "reaction-microscopes" / R. Moshammer ... [et al.]. Rydberg atoms: a microscale laboratory for studying electron-molecule tnteractions / F. B. Dunning -- Collisions involvintg photons. Quantum control of photochemical reaction dynamics and molecular functions / M. Yamaki ... [et al.]. Manipulating and viewing Rydberg wavepackets / R. R. Jones. Angle-resolved photoelectrons as a probe of strong-field interactions / M. Vrakking. Ultracold Rydberg atoms in a structured environment / I. C. H. Liu and J. M. Rost. Synchrotron-radiation-based recoil ion momentum spectroscopy of laser cooled and trapped cesium atoms / L. H. Coutinho. Reconstruction of attosecond pulse trains / Y. Mairesse ... [et al.]. Selective excitation of metastable atomic states by Femto- and attosecond laser pulses / A. D. Kondorskiy. Accurate calculations of triple differential cross sections for double photoionization of the hygrogen molecule / W. Vanroose ... [et al.]. Double and triple photoionization of Li and Be / J. Colgan, M. S. Pindzola and F. Robicheaux. Few/many body dynamics in strong laser fields / J. Zanghellini and T. Brabec. Rescattering-induced effects in electron-atom scattering in the presence of a circularly polarized laser field / A. V. Flegel ... [et al.]. Multidimensional photoelectron spectroscopy / P. Lablanquie ... [et al.]. Few photon and strongly driven transitions in the XUV and beyond / P. Lambropoulos, L. A. A. Nikolopoulos and S. I. Themelis. Ionization dynamics of atomic clusters in intense laser pulses / U. Saalmann and J. M. Rost. On the second order autocorrelation of an XUV attosecond pulse train / E. P. Benis ... [et al.]. Evidence for rescattering in molecular dissociation / I. D. Williams ... [et al.]. Photoionizing ions using synchrotron radiation / R. Phaneuf. Photo double

  13. Control of atomic transition rates via laser light shaping

    CERN Document Server

    Jauregui, R

    2015-01-01

    A modular systematic analysis of the feasibility of modifying atomic transition rates by tailoring the electromagnetic field of an external coherent light source is presented. The formalism considers both the center of mass and internal degrees of freedom of the atom, and all properties of the field: frequency, angular spectrum, and polarization. General features of recoil effects for internal forbidden transitions are discussed. A comparative analysis of different structured light sources is explicitly worked out. It includes spherical waves, Gaussian beams, Laguerre-Gaussian beams, and propagation invariant beams with closed analytical expressions. It is shown that increments in the order of magnitude of the transition rates for Gaussian and Laguerre-Gaussian beams, with respect to those obtained in the paraxial limit, requires waists of the order of the wavelength, while propagation invariant modes may considerably enhance transition rates under more favorable conditions. For transitions that can be natura...

  14. Hanbury Brown and Twiss and other atom-atom correlations: advances in quantum atom optics

    CERN Document Server

    CERN. Geneva

    2008-01-01

    Fifty years ago, two astronomers, R. Hanbury Brown and R. Q. Twiss, invented a new method to measure the angular diameter of stars, in spite of the atmospheric fluctuations. Their proposal prompted a hot debate among physicists : how might two particles (photons), emitted independently (at opposite extremities of a star) , behave in a correlated way when detected ? It was only after the development of R Glauber's full quantum analysis that the effect was understood as a two particle quantum interference effect. From a modern perspective, it can be viewed as an early example of the amazing properties of pairs of entangled particles. The effect has now been observed with bosonic and fermionic atoms, stressing its fully quantum character. After putting these experiments in a historical perspective, I will present recent results, and comment on their significance. I will also show how our single atom detection scheme has allowed us to demonstrate the creation of atom pairs by non linear mixing of matter wa...

  15. Influence of atom-photon correlations on atom-atom entanglement

    CERN Document Server

    Lastra, F

    2009-01-01

    The electronic entanglement between two atoms is obtained including the effects of photon recoil, for the case when quantum dispersion can be neglected during the atomic excited-state lifetime. Different from previous treatments using common or statistically independent reservoirs, a continuous transition between these limits is observed, that depends on the inter-atomic distance and degree of localization. The occurance of entanglement sudden death and birth as predicted by the presented Wigner-Weisskopf theory deviates from previous results using master equations in Born-Markov approximation. Moreover, the creation of a dark state is predicted, which manifests itself by a stationary entanglement that even may be created from an initially separable state.

  16. Atomism from Newton to Dalton.

    Science.gov (United States)

    Schofield, Robert E.

    1981-01-01

    Indicates that although Newton's achievements were rooted in an atomistic theory of matter resembling aspects of modern nuclear physics, Dalton developed his chemical atomism on the basis of the character of the gross behavior of substances rather than their particulate nature. (Author/SK)

  17. Spectroscopy, Understanding the Atom Series.

    Science.gov (United States)

    Hellman, Hal

    This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

  18. Atoms at the Science Fair

    Energy Technology Data Exchange (ETDEWEB)

    LeCompte, Robert G. [AEC Division of Technical Information; Wood, Burrell L. [AEC Division of Special Projects

    1968-01-01

    The United States Atomic Energy Commission has prepared this booklet to help young science fair exhibitors, their science teachers, project counselors, and parents. The booklet suggests some of the numerous nuclear topics on which students can base meaningful science projects. It offers all exhibitors advice on how to plan, design, and construct successful exhibits.

  19. Die sonderbare Welt der Atome

    CERN Multimedia

    Greschik, Stefan

    2003-01-01

    Is a Pinhead small? Or a grain of sand? The components of our world are still infinitely much tinier. Come with us in the dimensions, in that of the giant bacteria and even of atoms large like solar systems (3½ pages)

  20. Investigations into ultrasound induced atomization.

    Science.gov (United States)

    Ramisetty, Kiran A; Pandit, Aniruddha B; Gogate, Parag R

    2013-01-01

    The present work deals with measurements of the droplet size distribution in an ultrasonic atomizer using photographic analysis with an objective of understanding the effect of different equipment parameters such as the operating frequency, power dissipation and the operating parameters such as the flow rate and liquid properties on the droplet size distribution. Mechanistic details about the atomization phenomena have also been established using photographic analysis based on the capture of the growth of the instability and sudden ejection of droplets with high velocity. Velocity of these droplets has been measured by capturing the motion of droplets as streaks. It has been observed that the droplet size decreases with an increase in the frequency of atomizer. Droplet size distribution was found to change from the narrow to wider range with an increase in the intensity of ultrasound. The drop size was found to decrease with an increase in the fluid viscosity. The current work has clearly highlighted the approach for the selection of operating parameters for achieving a desired droplet size distribution using ultrasonic atomization and has also established the controlling mechanisms for the formation of droplet. An empirical correlation for the prediction of the droplet size has been developed based on the liquid and equipment operating properties.