WorldWideScience

Sample records for high charge optical

  1. Optical conductivity and optical effective mass in a high-mobility organic semiconductor: Implications for the nature of charge transport

    KAUST Repository

    Li, Yuan

    2014-12-03

    We present a multiscale modeling of the infrared optical properties of the rubrene crystal. The results are in very good agreement with the experimental data that point to nonmonotonic features in the optical conductivity spectrum and small optical effective masses. We find that, in the static-disorder approximation, the nonlocal electron-phonon interactions stemming from low-frequency lattice vibrations can decrease the optical effective masses and lead to lighter quasiparticles. On the other hand, the charge-transport and infrared optical properties of the rubrene crystal at room temperature are demonstrated to be governed by localized carriers driven by inherent thermal disorders. Our findings underline that the presence of apparently light carriers in high-mobility organic semiconductors does not necessarily imply bandlike transport.

  2. Optical conductivity and optical effective mass in a high-mobility organic semiconductor: Implications for the nature of charge transport

    KAUST Repository

    Li, Yuan; Yi, Yuanping; Coropceanu, Veaceslav; Bredas, Jean-Luc

    2014-01-01

    We present a multiscale modeling of the infrared optical properties of the rubrene crystal. The results are in very good agreement with the experimental data that point to nonmonotonic features in the optical conductivity spectrum and small optical effective masses. We find that, in the static-disorder approximation, the nonlocal electron-phonon interactions stemming from low-frequency lattice vibrations can decrease the optical effective masses and lead to lighter quasiparticles. On the other hand, the charge-transport and infrared optical properties of the rubrene crystal at room temperature are demonstrated to be governed by localized carriers driven by inherent thermal disorders. Our findings underline that the presence of apparently light carriers in high-mobility organic semiconductors does not necessarily imply bandlike transport.

  3. Production of highly charged ions of argon by optical field ionization in a relativistic laser field

    International Nuclear Information System (INIS)

    Sagisaka, Akito; Akahane, Yutaka; Aoyama, Makoto; Nakano, Fumihiko; Yamakawa, Koichi

    2001-01-01

    We observed the highly charged ions of argon by optical field ionization in a relativistic intensity regime. Charge states up to Ar 15+ were produced at the highest intensity of 800 nm, linearly polarized 20 fs Ti: sapphire laser pulses. The peak intensity of the pulse is determined by comparing the measured ion production curve for Ar 9+ with ADK theory. The results of these measurements of the ionization indicate that the maximum peak intensity is achieved to ∼2x10 19 W/cm 2 . (author)

  4. High Pressure Optical Studies of the Thallous Halides and of Charge-Transfer Complexes

    Science.gov (United States)

    Jurgensen, Charles Willard

    High pressure was used to study the insulator -to-metal transition in sulfur and the thallous halides and to study the intermolecular interactions in charge -transfer complexes. The approach to the band overlap insulator -to-metal transition was studied in three thallous halides and sulfur by optical absorption measurements of the band gap as a function of pressure. The band gap of sulfur continuously decreases with pressure up to the insulator -to-metal transition which occurs between 450 and 485 kbars. The results on the thallous halides indicate that the indirect gap decreases more rapidly than the direct gap; the closing of the indirect gap is responsible for the observed insulator -to-metal transitions. High pressure electronic and vibrational spectroscopic measurements on the solid-state complexes of HMB-TCNE were used to study the intermolecular interactions of charge -transfer complexes. The vibrational frequency shifts indicate that the degree of charge transfer increases with pressure which is independently confirmed by an increase in the molar absorptivity of the electronic charge-transfer peak. Induction and dispersion forces contribute towards a red shift of the charge-transfer peak; however, charge-transfer resonance contributes toward a blue shift and this effect is dominant for the HMB-TCNE complexes. High pressure electronic spectra were used to study the effect of intermolecular interactions on the electronic states of TCNQ and its complexes. The red shifts with pressure of the electronic spectra of TCNQ and (TCNQ)(' -) in polymer media and of crystalline TCNQ can be understood in terms of Van der Waals interactions. None of the calculations which considered intradimer distance obtained the proper behavior for either the charge-transfer of the locally excited states of the complexes. The qualitative behavior of both states can be interpreted as the effect of increased mixing of the locally excited and charge transfer states.

  5. Quantum mechanics of charged particle beam optics

    CERN Document Server

    Khan, Sameen Ahmed

    2018-01-01

    Theory of charged particle beam optics is basic to the design and working of charged particle beam devices from electron microscopes to accelerator machines. Traditionally, the optical elements of the devices are designed and operated based on classical mechanics and classical electromagnetism, and only certain specific quantum mechanical aspects are dealt with separately using quantum theory. This book provides a systematic approach to quantum theory of charged particle beam optics, particularly in the high energy cases such as accelerators or high energy electron microscopy.

  6. Optics of charged particles

    International Nuclear Information System (INIS)

    Wollnik, H.

    1987-01-01

    Suitable for both the specialist and non-specialist, this book develops all statements from first principles. Key chapters of the book focus upon how to design particle-optical systems, the systematics of image abberations, the effects of fringing fields, systematics of beams, and solutions for particle-optical systems. An undergraduate background in physics and mathematics is required for this work

  7. DeVelopment of the high-intensity polarized H- source with proton charge exchange on sodium optically oriented atoms

    International Nuclear Information System (INIS)

    Zelenskij, A.N.; Kokhanovskij, S.A.

    1982-01-01

    The results of experimental study on the source of polarized H - ions at polarized electron capture by proton from optically oriented sodium atoms are presented. Circular-polarized dye laser radiation with lamp pumping is used for polarization of highly dense sodium vapors in the pulsed mode. A facility for polarization measurement in the ion source is described. Dependence of the counting rate of metastables for the right and left circular radiation polarization in respect to wave length is presented. The results of measuring the degree of polarization under change of sodium density are revealed. The measurements have disclosed that obtaining of high polarization degree at 20-30% charge exchange effectiveness is possible but large radiation power is required. Use of a dense charge exchange target provides high effectiveness of hte whole polarization process. Yield of polarized H - ions can approach 10 μA/1 mA of the initial proton current

  8. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    International Nuclear Information System (INIS)

    Kovalenko, Oleksandr

    2015-01-01

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U 90+ beam at the existing storage ring ESR, GSI.

  9. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  10. Geometrical charged-particle optics

    CERN Document Server

    Rose, Harald

    2012-01-01

    This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are...

  11. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.; Abdelghany, Mohamed A.; Elsayed, Mohannad Yomn; Elshurafa, Amro M; Salama, Khaled N.

    2014-01-01

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  12. High Voltage Charge Pump

    KAUST Repository

    Emira, Ahmed A.

    2014-10-09

    Various embodiments of a high voltage charge pump are described. One embodiment is a charge pump circuit that comprises a plurality of switching stages each including a clock input, a clock input inverse, a clock output, and a clock output inverse. The circuit further comprises a plurality of pumping capacitors, wherein one or more pumping capacitors are coupled to a corresponding switching stage. The circuit also comprises a maximum selection circuit coupled to a last switching stage among the plurality of switching stages, the maximum selection circuit configured to filter noise on the output clock and the output clock inverse of the last switching stage, the maximum selection circuit further configured to generate a DC output voltage based on the output clock and the output clock inverse of the last switching stage.

  13. High-frequency conductivity of optically excited charge carriers in hydrogenated nanocrystalline silicon investigated by spectroscopic femtosecond pump–probe reflectivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    He, Wei [University of Birmingham, School of Physics and Astronomy, Birmingham B15 2TT (United Kingdom); Yurkevich, Igor V. [Aston University, Nonlinearity and Complexity Research Group, Birmingham B4 7ET (United Kingdom); Zakar, Ammar [University of Birmingham, School of Physics and Astronomy, Birmingham B15 2TT (United Kingdom); Kaplan, Andrey, E-mail: a.kaplan.1@bham.ac.uk [University of Birmingham, School of Physics and Astronomy, Birmingham B15 2TT (United Kingdom)

    2015-10-01

    We report an investigation into the high-frequency conductivity of optically excited charge carriers far from equilibrium with the lattice. The investigated samples consist of hydrogenated nanocrystalline silicon films grown on a thin film of silicon oxide on top of a silicon substrate. For the investigation, we used an optical femtosecond pump–probe setup to measure the reflectance change of a probe beam. The pump beam ranged between 580 and 820 nm, whereas the probe wavelength spanned 770 to 810 nm. The pump fluence was fixed at 0.6 mJ/cm{sup 2}. We show that at a fixed delay time of 300 fs, the conductivity of the excited electron–hole plasma is described well by a classical conductivity model of a hot charge carrier gas found at Maxwell–Boltzmann distribution, while Fermi–Dirac statics is not suitable. This is corroborated by values retrieved from pump–probe reflectance measurements of the conductivity and its dependence on the excitation wavelength and carrier temperature. The conductivity decreases monotonically as a function of the excitation wavelength, as expected for a nondegenerate charge carrier gas. - Highlights: • We study high‐frequency conductivity of excited hydrogenated nanocrystalline silicon. • Reflectance change was measured as a function of pump and probe wavelength. • Maxwell–Boltzmann transport theory was used to retrieve the conductivity. • The conductivity decreases monotonically as a function of the pump wavelength.

  14. Electro-optical Detection of Charged Particles

    International Nuclear Information System (INIS)

    Lazarus, D.M.

    2001-01-01

    The electric field of charged particles can induce transient changes in the polarization of light that produce sub-picosecond modulation of a laser beam. This is a consequence of the electro-optical effect in which the presence of the electric field in an electro-optical medium produces a change in the index of refraction of the medium resulting in a phase retardation between polarization components parallel and perpendicular to the electric field. We have observed the electro-optical effect due to 10 picosecond electron beam bunches with rise times that were limited by the bandwidth of our data acquisition system. This technology is being applied to particle beam diagnostics and has the potential to produce charged particle detectors combining excellent spatial resolution with unprecedented temporal precision.

  15. Electro-optical detection of charged particles

    International Nuclear Information System (INIS)

    Semertzidis, Y.K.; Castillo, V.; Kowalski, L.; Kraus, D.E.; Larsen, R.; Lazarus, D.M.; Magurno, B.; Nikas, D.; Ozben, C.; Srinivasan-Rao, T.; Tsang, T.

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams

  16. Electro-optical detection of charged particles

    CERN Document Server

    Semertzidis, Y K; Kowalski, L A; Kraus, D E; Larsen, R; Lazarus, D M; Magurno, B; Nikas, D; Ozben, C; Srinivasan-Rao, T; Tsang, Thomas

    2000-01-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO sub 3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  17. Electro-optical detection of charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Semertzidis, Y.K.; Castillo, V.; Kowalski, L.; Kraus, D.E.; Larsen, R.; Lazarus, D.M. E-mail: lazarus@sun2.bnl.gov; Magurno, B.; Nikas, D.; Ozben, C.; Srinivasan-Rao, T.; Tsang, T

    2000-10-01

    We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO{sub 3} crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds good for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

  18. Geometrical charged-particle optics. 2. ed.

    International Nuclear Information System (INIS)

    Rose, Harald

    2013-01-01

    Provides a unique theoretical treatment of charged-particle optics. Displays novel unpublished results on several topics. Provides insight into the properties of charged-particle devices. Treats wave optical properties of the electron. Presents the resolution limit of electron microscopes and novel theoretical treatment of the Stern-Gerlach effect. This second edition is an extended version of the first edition of Geometrical Charged-Particle Optics. The updated reference monograph is intended as a guide for researchers and graduate students who are seeking a comprehensive treatment of the design of instruments and beam-guiding systems of charged particles and their propagation in electromagnetic fields. Wave aspects are included in this edition for explaining electron holography, the Aharanov-Bohm effect and the resolution of electron microscopes limited by diffraction. Several methods for calculating the electromagnetic field are presented and procedures are outlined for calculating the properties of systems with arbitrarily curved axis. Detailed methods are presented for designing and optimizing special components such as aberration correctors, spectrometers, energy filters monochromators, ion traps, electron mirrors and cathode lenses. In particular, the optics of rotationally symmetric lenses, quadrupoles, and systems composed of these elements are discussed extensively. Beam properties such as emittance, brightness, transmissivity and the formation of caustics are outlined. Relativistic motion and spin precession of the electron are treated in a covariant way by introducing the Lorentz-invariant universal time and by extending Hamilton's principle from three to four spatial dimensions where the laboratory time is considered as the fourth pseudo-spatial coordinate. Using this procedure and introducing the self action of the electron, its accompanying electromagnetic field and its radiation field are calculated for arbitrary motion. In addition, the Stern

  19. Quantum memory on a charge qubit in an optical microresonator

    Science.gov (United States)

    Tsukanov, A. V.

    2017-10-01

    A quantum-memory unit scheme on the base of a semiconductor structure with quantum dots is proposed. The unit includes a microresonator with single and double quantum dots performing frequencyconverter and charge-qubit functions, respectively. The writing process is carried out in several stages and it is controlled by optical fields of the resonator and laser. It is shown that, to achieve high writing probability, it is necessary to use high-Q resonators and to be able to suppress relaxation processes in quantum dots.

  20. Mechanisms of charge transfer and redistribution in LaAlO3/SrTiO3 revealed by high-energy optical conductivity.

    Science.gov (United States)

    Asmara, T C; Annadi, A; Santoso, I; Gogoi, P K; Kotlov, A; Omer, H M; Motapothula, M; Breese, M B H; Rübhausen, M; Venkatesan, T; Ariando; Rusydi, A

    2014-04-14

    In condensed matter physics the quasi two-dimensional electron gas at the interface of two different insulators, polar LaAlO3 on nonpolar SrTiO3 (LaAlO3/SrTiO3) is a spectacular and surprising observation. This phenomenon is LaAlO3 film thickness dependent and may be explained by the polarization catastrophe model, in which a charge transfer of 0.5e(-) from the LaAlO3 film into the LaAlO3/SrTiO3 interface is expected. Here we show that in conducting samples (≥ 4 unit cells of LaAlO3) there is indeed a ~0.5e(-) transfer from LaAlO3 into the LaAlO3/SrTiO3 interface by studying the optical conductivity in a broad energy range (0.5-35 eV). Surprisingly, in insulating samples (≤ 3 unit cells of LaAlO3) a redistribution of charges within the polar LaAlO3 sublayers (from AlO2 to LaO) as large as ~0.5e(-) is observed, with no charge transfer into the interface. Hence, our results reveal the different mechanisms for the polarization catastrophe compensation in insulating and conducting LaAlO3/SrTiO3 interfaces.

  1. Surface charge compensation for a highly charged ion emission microscope

    International Nuclear Information System (INIS)

    McDonald, J.W.; Hamza, A.V.; Newman, M.W.; Holder, J.P.; Schneider, D.H.G.; Schenkel, T.

    2003-01-01

    A surface charge compensation electron flood gun has been added to the Lawrence Livermore National Laboratory (LLNL) highly charged ion (HCI) emission microscope. HCI surface interaction results in a significant charge residue being left on the surface of insulators and semiconductors. This residual charge causes undesirable aberrations in the microscope images and a reduction of the Time-Of-Flight (TOF) mass resolution when studying the surfaces of insulators and semiconductors. The benefits and problems associated with HCI microscopy and recent results of the electron flood gun enhanced HCI microscope are discussed

  2. Optical Spectroscopy Of Charged Quantum Dot Molecules

    Science.gov (United States)

    Scheibner, M.; Bracker, A. S.; Stinaff, E. A.; Doty, M. F.; Gammon, D.; Ponomarev, I. V.; Reinecke, T. L.; Korenev, V. L.

    2007-04-01

    Coupling between two closely spaced quantum dots is observed by means of photoluminescence spectroscopy. Hole coupling is realized by rational crystal growth and heterostructure design. We identify molecular resonances of different excitonic charge states, including the important case of a doubly charged quantum dot molecule.

  3. Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

    Science.gov (United States)

    Bracker, A. S.; Stinaff, E. A.; Gammon, D.; Ware, M. E.; Tischler, J. G.; Shabaev, A.; Efros, Al. L.; Park, D.; Gershoni, D.; Korenev, V. L.; Merkulov, I. A.

    2005-02-01

    We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

  4. OPTICALLY BASED CHARGE INJECTION SYSTEM FOR IONIZATION DETECTORS

    International Nuclear Information System (INIS)

    CHEN, H.; CITTERIO, M.; LANNI, F.; LEITE, M.A.L.; RADEKA, V.; RESCIA, S.; TAKAI, H.

    2001-01-01

    An optically coupled charge injection system for ionization based radiation detectors which allows a test charge to be injected without the creation of ground loops has been developed. An ionization like signal from an external source is brought into the detector through an optical fiber and injected into the electrodes by means of a photodiode. As an application example, crosstalk measurements on a liquid Argon electromagnetic calorimeter readout electrodes were performed

  5. Highly Sensitive Optical Receivers

    CERN Document Server

    Schneider, Kerstin

    2006-01-01

    Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

  6. High Collection Nonimaging Optics

    Science.gov (United States)

    Winston, Roland

    1989-07-01

    Nonimaging optics departs from the methods of traditional optical design to develop instead techniques for maximizing the collecting power of concentrating elements and systems. Designs which exceed the concentration attainable with focusing techniques by factors of four or more and approach the theoretical limit are possible (ideal concentrators). The methodology for designing high collection nonirnaging systems is described.

  7. Iron free permanent magnet systems for charged particle beam optics

    International Nuclear Information System (INIS)

    Lund, S.M.; Halbach, K.

    1995-01-01

    The strength and astounding simplicity of certain permanent magnet materials allow a wide variety of simple, compact configurations of high field strength and quality multipole magnets. Here we analyze the important class of iron-free permanent magnet systems for charged particle beam optics. The theory of conventional segmented multipole magnets formed from uniformly magnetized block magnets placed in regular arrays about a circular magnet aperture is reviewed. Practical multipole configurations resulting are presented that are capable of high and intermediate aperture field strengths. A new class of elliptical aperture magnets is presented within a model with continuously varying magnetization angle. Segmented versions of these magnets promise practical high field dipole and quadrupole magnets with an increased range of applicability

  8. Optical patterning of trapped charge in nitrogen-doped diamond

    Science.gov (United States)

    Jayakumar, Harishankar; Henshaw, Jacob; Dhomkar, Siddharth; Pagliero, Daniela; Laraoui, Abdelghani; Manson, Neil B.; Albu, Remus; Doherty, Marcus W.; Meriles, Carlos A.

    2016-08-01

    The nitrogen-vacancy (NV) centre in diamond is emerging as a promising platform for solid-state quantum information processing and nanoscale metrology. Of interest in these applications is the manipulation of the NV charge, which can be attained by optical excitation. Here, we use two-colour optical microscopy to investigate the dynamics of NV photo-ionization, charge diffusion and trapping in type-1b diamond. We combine fixed-point laser excitation and scanning fluorescence imaging to locally alter the concentration of negatively charged NVs, and to subsequently probe the corresponding redistribution of charge. We uncover the formation of spatial patterns of trapped charge, which we qualitatively reproduce via a model of the interplay between photo-excited carriers and atomic defects. Further, by using the NV as a probe, we map the relative fraction of positively charged nitrogen on localized optical excitation. These observations may prove important to transporting quantum information between NVs or to developing three-dimensional, charge-based memories.

  9. Topological charge algebra of optical vortices in nonlinear interactions.

    Science.gov (United States)

    Zhdanova, Alexandra A; Shutova, Mariia; Bahari, Aysan; Zhi, Miaochan; Sokolov, Alexei V

    2015-12-28

    We investigate the transfer of orbital angular momentum among multiple beams involved in a coherent Raman interaction. We use a liquid crystal light modulator to shape pump and Stokes beams into optical vortices with various integer values of topological charge, and cross them in a Raman-active crystal to produce multiple Stokes and anti-Stokes sidebands. We measure the resultant vortex charges using a tilted-lens technique. We verify that in every case the generated beams' topological charges obey a simple relationship, resulting from angular momentum conservation for created and annihilated photons, or equivalently, from phase-matching considerations for multiple interacting beams.

  10. 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.

  11. Mass spectrometer provided with an optical system for separating neutron particles against charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Reeher, J R; Story, M S; Smith, R D

    1977-03-03

    This invention concerns a mass spectrometer with an ion focusing optical system that efficiently separates the charged and neutral particles. It concerns an apparatus that can be used in ionisation areas operating at relatively high pressure (> 10/sup -2/ Torr). The invention relates more particularly to a mass spectrometer with an inlet device for the samples to be identified, a sample ionisation system for forming charged and neutral particles, a mass analyser and an optical system for focusing the ions formed in the mass analyser. The optics include several conducting components of which at least one has sides formed of grids, in the direction of the axis, towards the analyser the optics forming a potential well along the axis. The selected charged particles are focused in the analyser and the remaining particles can escape by the openings in the conducting grids.

  12. Charged current weak interactions at high energy

    International Nuclear Information System (INIS)

    Cline, D.

    1977-01-01

    We review high energy neutrino and antineutrino charged current interactions. An overview of the experimental data is given, including a discussion of the experimental status of the y anomaly. Locality tests, μ-e universality and charge symmetry invariance tests are discussed. Charm production is discussed. The experimental status of trimuon events and possible phenomenological models for these events are presented. (orig.) [de

  13. ECRIS sources for highly charged ions

    International Nuclear Information System (INIS)

    Geller, R.

    1991-01-01

    The so-called Philips ionization gauge ion sources (PIGIS) were used until quite recently in heavy ion accelerators so multiply charged ions could only be obtained by incorporating a stripper to remove electrons. Electron cyclotron resonance ion sources (ECRIS) now dominate as they produce more highly charged ions. (orig.)

  14. Lateral phase drift of the topological charge density in stochastic optical fields

    CSIR Research Space (South Africa)

    Roux, FS

    2012-03-01

    Full Text Available The statistical distributions of optical vortices or topological charge in stochastic optical fields can be inhomogeneous in both transverse directions. Such two-dimensional inhomogeneous vortex or topological charge distributions evolve in a...

  15. Charge transport in highly efficient iridium cored electrophosphorescent dendrimers

    Science.gov (United States)

    Markham, Jonathan P. J.; Samuel, Ifor D. W.; Lo, Shih-Chun; Burn, Paul L.; Weiter, Martin; Bässler, Heinz

    2004-01-01

    Electrophosphorescent dendrimers are promising materials for highly efficient light-emitting diodes. They consist of a phosphorescent core onto which dendritic groups are attached. Here, we present an investigation into the optical and electronic properties of highly efficient phosphorescent dendrimers. The effect of dendrimer structure on charge transport and optical properties is studied using temperature-dependent charge-generation-layer time-of-flight measurements and current voltage (I-V) analysis. A model is used to explain trends seen in the I-V characteristics. We demonstrate that fine tuning the mobility by chemical structure is possible in these dendrimers and show that this can lead to highly efficient bilayer dendrimer light-emitting diodes with neat emissive layers. Power efficiencies of 20 lm/W were measured for devices containing a second-generation (G2) Ir(ppy)3 dendrimer with a 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene electron transport layer.

  16. Highly charged ion trapping and cooling

    International Nuclear Information System (INIS)

    Beck, B. R.; Church, D. A.; Gruber, L.; Holder, J. P.; Schneider, D.; Steiger, J.

    1998-01-01

    In the past few years a cryogenic Penning trap (RETRAP) has been operational at the Electron Beam Ion Trap (EBIT) facility at Lawrence Livermore National Laboratory. The combination of RETRAP and EBIT provides a unique possibility of producing and re-trapping highly charged ions and cooling them to very low temperatures. Due to the high Coulomb potentials in such an ensemble of cold highly charged ions the Coulomb coupling parameter (the ratio of Coulomb potential to the thermal energy) can easily reach values of 172 and more. To study such systems is not only of interest in astrophysics to simulate White Dwarf star interiors but opens up new possibilities in a variety of areas (e.g. laser spectroscopy), cold highly charged ion beams

  17. Charged vortices in high-Tc superconductors

    International Nuclear Information System (INIS)

    Matsuda, Y.; Kumagai, K.

    2002-01-01

    It is well known that a vortex in type II superconductors traps a magnetic flux. Recently the possibility that a vortex can accumulate a finite electric charge as well has come to be realized. The sign and magnitude of the vortex charge not only is closely related to the microscopic electronic structure of the vortex, but also strongly affects the dynamical properties of the vortex. In this chapter we demonstrate that a vortex in high-T c superconductors (HTSC) indeed traps a finite electronic charge, using the high resolution measurements of the nuclear quadrupole frequencies. We then discuss the vortex Hall anomaly whose relation with the vortex charging effect has recently received considerable attention. We show that the sign of the trapped charge is opposite to the sign predicted by the conventional BCS theory and deviation of the magnitude of the charge from the theory is also significant. We also show that the electronic structure of underlying system is responsible for the Hall sign in the vortex state and again the Hall sign is opposite to the sign predicted by the BCS theory. It appears that these unexpected features observed in both electrostatics and dynamics of the vortex may be attributed to the novel electronic structure of the vortex in HTSC. (orig.)

  18. Acoustic charge manipulation in semiconductor nanostructures for optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Voelk, Stefan

    2010-07-30

    Within this thesis, the influence of a surface acoustic wave (SAW) on the luminescence of semiconductor nanostructures is investigated. Beginning with the physics of low-dimensional semiconductor structures, the quantum mechanical and optical properties of quantum dot (QD) systems are discussed. In particular, intrinsic parameters of QDs such as morphology, composition, strain and occupation with carriers are taken into account. Subsequently, the influence of an applied electric field and of externally induced strain are introduced. From this general approach, the discussion is focused to quantum posts (QPs) which are columnar shaped semiconductor nanostructures. In contrast to conventional self-assembled QDs, the height of the QPs can be controlled by the epitaxial growth process. Due to the adjustable height, electronic states and therefore the exciton transition energies can be tailored. Furthermore, QPs are embedded in a matrix-quantum-well structure which has important influence on the carrier dynamic if a SAW is excited on the sample. Mainly, two effects have to be considered regarding the interaction of charge carriers with SAWs: deformation potential coupling and acousto-electric coupling. For the investigated material and used SAW frequencies, acousto-electric coupling dominates the interaction between charges and SAW. For a quantum well (QW) structure, the periodic band modulation dissociates excitons into sequential stripes of electrons and holes which then are conveyed by the SAW. This so called bipolar transport or charge conveyance effect can be used to inject carriers into remote QD structures and has already been demonstrated for QD ensembles. The injection of carriers into individual quantum posts is successfully demonstrated for the first time within this work. The spectrally resolved photoluminescence (PL) data of individual QPs show an unexpected switching of PL lines which cannot be induced by varying other parameters, e.g. the laser intensity

  19. Optical properties of two-dimensional charge density wave materials

    Science.gov (United States)

    Sayers, Charles; Karbassi, Sara; Friedemann, Sven; da Como, Enrico

    Titanium diselenide (TiSe2) is a member of the layered transition metal dichalcogenide (TMD) materials. It exhibits unusual chiral charge ordering below 190 K after undergoing an initial phase transition to a commensurate (2 x 2 x 2) charge density wave (CDW) at 200 K which is enhanced further in the monolayer. Recently, the first evidence of chirality in a CDW system was discovered in this material by scanning tunneling microscopy and time-resolved reflectivity experiments, where separate left and right handed charge-ordered domains were found to exist within a single sample. We have prepared single crystals of 1T-TiSe2 using iodine vapour transport, and confirmed their quality by x-ray analysis and charge transport measurements. Using a combination of polarised optical spectroscopy techniques in the mid to far infrared (4 to 700 meV photon energy), we have measured an anisotropy relating to the CDW gap. We discuss the results on the basis of chiral domains with different handedness and the nature of the CDW transition.

  20. Beta decay of highly charged ions

    International Nuclear Information System (INIS)

    Litvinov, Yuri A; Bosch, Fritz

    2011-01-01

    Beta decay of highly charged ions has attracted much attention in recent years. An obvious motivation for this research is that stellar nucleosynthesis proceeds at high temperatures where the involved atoms are highly ionized. Another important reason is addressing decays of well-defined quantum-mechanical systems, such as one-electron ions where all interactions with other electrons are excluded. The largest modifications of nuclear half-lives with respect to neutral atoms have been observed in beta decay of highly charged ions. These studies can be performed solely at ion storage rings and ion traps, because there high atomic charge states can be preserved for extended periods of time (up to several hours). Currently, all experimental results available in this field originate from experiments at the heavy-ion complex GSI in Darmstadt. There, the fragment separator facility FRS allows the production and separation of exotic, highly charged nuclides, which can then be stored and investigated in the storage ring facility ESR. In this review, we present and discuss in particular two-body beta decays, namely bound-state beta decay and orbital electron capture. Although we focus on experiments conducted at GSI, we will also attempt to provide general requirements common to any other experiment in this context. Finally, we address challenging but not yet performed experiments and we give prospects for the new radioactive beam facilities, such as FAIR in Darmstadt, IMP in Lanzhou and RIKEN in Wako.

  1. First- and second-order charged particle optics

    International Nuclear Information System (INIS)

    Brown, K.L.; Servranckx, R.V.

    1984-07-01

    Since the invention of the alternating gradient principle there has been a rapid evolution of the mathematics and physics techniques applicable to charged particle optics. In this publication we derive a differential equation and a matrix algebra formalism valid to second-order to present the basic principles governing the design of charged particle beam transport systems. A notation first introduced by John Streib is used to convey the essential principles dictating the design of such beam transport systems. For example the momentum dispersion, the momentum resolution, and all second-order aberrations are expressed as simple integrals of the first-order trajectories (matrix elements) and of the magnetic field parameters (multipole components) characterizing the system. 16 references, 30 figures

  2. Optical pumping of electron and nuclear spin in a negatively-charged quantum dot

    Science.gov (United States)

    Bracker, Allan; Gershoni, David; Korenev, Vladimir

    2005-03-01

    We report optical pumping of electron and nuclear spins in an individual negatively-charged quantum dot. With a bias-controlled heterostructure, we inject one electron into the quantum dot. Intense laser excitation produces negative photoluminescence polarization, which is easily erased by the Hanle effect, demonstrating optical pumping of a long-lived resident electron. The electron spin lifetime is consistent with the influence of nuclear spin fluctuations. Measuring the Overhauser effect in high magnetic fields, we observe a high degree of nuclear spin polarization, which is closely correlated to electron spin pumping.

  3. Photoinduced High-Frequency Charge Oscillations in Dimerized Systems

    Science.gov (United States)

    Yonemitsu, Kenji

    2018-04-01

    Photoinduced charge dynamics in dimerized systems is studied on the basis of the exact diagonalization method and the time-dependent Schrödinger equation for a one-dimensional spinless-fermion model at half filling and a two-dimensional model for κ-(bis[ethylenedithio]tetrathiafulvalene)2X [κ-(BEDT-TTF)2X] at three-quarter filling. After the application of a one-cycle pulse of a specifically polarized electric field, the charge densities at half of the sites of the system oscillate in the same phase and those at the other half oscillate in the opposite phase. For weak fields, the Fourier transform of the time profile of the charge density at any site after photoexcitation has peaks for finite-sized systems that correspond to those of the steady-state optical conductivity spectrum. For strong fields, these peaks are suppressed and a new peak appears on the high-energy side, that is, the charge densities mainly oscillate with a single frequency, although the oscillation is eventually damped. In the two-dimensional case without intersite repulsion and in the one-dimensional case, this frequency corresponds to charge-transfer processes by which all the bonds connecting the two classes of sites are exploited. Thus, this oscillation behaves as an electronic breathing mode. The relevance of the new peak to a recently found reflectivity peak in κ-(BEDT-TTF)2X after photoexcitation is discussed.

  4. Precision laser spectroscopy of highly charged ions

    International Nuclear Information System (INIS)

    Kuehl, T.; Borneis, S.; Becker, S.; Dax, A.; Engel, T.; Grieser, R.; Huber, G.; Klaft, I.; Klepper, O.; Kohl, A.; Marx, D.; Meier, K.; Neumann, R.; Schmitt, F.; Seelig, P.; Voelker, L.

    1996-01-01

    Recently, intense beams of highly charged ions have become available at heavy ion cooler rings. The obstacle for producing these highly interesting candidates is the large binding energy of K-shell electrons in heavy systems in excess of 100 keV. One way to remove these electrons is to strip them off by passing the ion through material. In the cooler ring, the ions are cooled to a well defined velocity. At the SIS/ESR complex it is possible to produce, store, and cool highly charged ions up to bare uranium with intensities exceeding 10 8 atoms in the ring. This opens the door for precision laser spectroscopy of hydrogenlike-heavy ions, e.g. 209 Bi 82+ , and allows to examine the interaction of the single electron with the large fields of the heavy nucleus, exceeding any artificially produced electric and magnetic fields by orders of magnitude. In the electron cooler the interaction of electrons and highly charged ions otherwise only present in the hottest plasmas can be studied. (orig.)

  5. High-LET charged particle radiotherapy

    International Nuclear Information System (INIS)

    Castro, J.R.; California Univ., San Francisco, CA

    1991-07-01

    The Department of Radiation Oncology at UCSF Medical Center and the Radiation Oncology Department at UC Lawrence Berkeley Laboratory have been evaluating the use of high LET charged particle radiotherapy in a Phase 1--2 research trial ongoing since 1979. In this clinical trail, 239 patients have received at least 10 Gy (physical) minimum tumor dose with neon ions, meaning that at least one-half of their total treatment was given with high-LET charged particle therapy. Ninety-one patients received all of their therapy with neon ions. Of the 239 patients irradiated, target sites included lesions in the skin, subcutaneous tissues, head and neck such as paranasal sinuses, nasopharynx and salivary glands (major and minor), skull base and juxtaspinal area, GI tract including esophagus, pancreas and biliary tract, prostate, lung, soft tissue and bone. Analysis of these patients has been carried out with a minimum followup period of 2 years

  6. Mechanisms for production of highly charged ions

    International Nuclear Information System (INIS)

    McGuire, J.H.

    1987-01-01

    Various experimental data at high collision velocity are interpreted in terms of direct (D) and rearrangement (R) mechanisms for production of multiply charged ions. We consider double ionization in helium by protons, electrons, heavy ions, antiprotons, positrons and photons. Qualitative differences are discussed in the context of the R and D mechanisms. Multiple ionization in many electron atoms is considered as is simultaneous capture and ionization and fragmentation of methane molecules. Some other theoretical methods are briefly discussed. (orig.)

  7. Lateral diffusion of the topological charge density in stochastic optical fields

    CSIR Research Space (South Africa)

    Roux, FS

    2010-01-01

    Full Text Available Stochastic (i.e. random and quasi-random) optical fields may contain distributions of optical vortices that are represented by non-uniform topological charge densities. Numerical simulations are used to investigate the evolution under free...

  8. Spectroscopy with trapped highly charged ions

    International Nuclear Information System (INIS)

    Beiersdorfer, Peter

    2009-01-01

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed; and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  9. High gradient lens for charged particle beam

    Science.gov (United States)

    Chen, Yu-Jiuan

    2014-04-29

    Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

  10. Highly charged ions generated with intense laser beams

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Jungwirth, Karel; Králiková, Božena; Láska, Leoš; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Hnatowicz, Vladimír; Peřina, Vratislav; Badziak, J.; Parys, P.; Wolowski, J.; Woryna, E.; Szydlowski, A.

    2003-01-01

    Roč. 205, - (2003), s. 355-359 ISSN 0168-583X. [International Symposium on Swift Heavy Ions in Matter /5./. Taormina-Giardini Naxos, 22.05.2002-25.05.2002] R&D Projects: GA MŠk LN00A100 Grant - others:HPRI(XE) CT-1999-00053; IAEA(XE) 11535/RO Institutional research plan: CEZ:AV0Z2043910; CEZ:AV0Z1010921 Keywords : laser-produced plasma * highly charged ions * ion implantation * windowless electron multiplier Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.041, year: 2003

  11. SLC injector simulation and tuning for high charge transport

    International Nuclear Information System (INIS)

    Yeremian, A.D.; Miller, R.H.; Clendenin, J.E.; Early, R.A.; Ross, M.C.; Turner, J.L.; Wang, J.W.

    1992-08-01

    We have simulated the SLC injector from the thermionic gun through the first accelerating section and used the resulting parameters to tune the injector for optimum performance and high charge transport. Simulations are conducted using PARMELA, a three-dimensional ray-trace code with a two-dimensional space-charge model. The magnetic field profile due to the existing magnetic optics is calculated using POISSON, while SUPERFISH is used to calculate the space harmonics of the various bunchers and the accelerator cavities. The initial beam conditions in the PARMELA code are derived from the EGUN model of the gun. The resulting injector parameters from the PARMELA simulation are used to prescribe experimental settings of the injector components. The experimental results are in agreement with the results of the integrated injector model

  12. SLC injector simulation and tuning for high charge transport

    International Nuclear Information System (INIS)

    Yeremian, A.D.; Miller, R.H.; Clendenin, J.E.; Early, R.A.; Ross, M.C.; Turner, J.L.; Wang, J.W.

    1992-01-01

    We have simulated the SLC injector from the thermionic gun through the first accelerating section and used the resulting parameters to tune the injector for optimum performance and high charge transport. Simulations are conducted using PARMELA, a three-dimensional space-charge model. The magnetic field profile due to the existing magnetic optics is calculated using POISSON, while SUPERFISH is used to calculate the space harmonics of the various bunchers and the accelerator cavities. The initial beam conditions in the PARMELA code are derived from the EGUN model of the gun. The resulting injector parameters from the PARMELA simulation are used to prescribe experimental settings of the injector components. The experimental results are in agreement with the results of the integrated injector model. (Author) 5 figs., 7 refs

  13. Adaptive matching of the iota ring linear optics for space charge compensation

    Energy Technology Data Exchange (ETDEWEB)

    Romanov, A. [Fermilab; Bruhwiler, D. L. [RadiaSoft, Boulder; Cook, N. [RadiaSoft, Boulder; Hall, C. [RadiaSoft, Boulder

    2016-10-09

    Many present and future accelerators must operate with high intensity beams when distortions induced by space charge forces are among major limiting factors. Betatron tune depression of above approximately 0.1 per cell leads to significant distortions of linear optics. Many aspects of machine operation depend on proper relations between lattice functions and phase advances, and can be i proved with proper treatment of space charge effects. We implement an adaptive algorithm for linear lattice re matching with full account of space charge in the linear approximation for the case of Fermilab’s IOTA ring. The method is based on a search for initial second moments that give closed solution and, at the same predefined set of goals for emittances, beta functions, dispersions and phase advances at and between points of interest. Iterative singular value decomposition based technique is used to search for optimum by varying wide array of model parameters

  14. Amplified Sensitivity of Nitrogen-Vacancy Spins in Nanodiamonds Using All-Optical Charge Readout.

    Science.gov (United States)

    Hopper, David A; Grote, Richard R; Parks, Samuel M; Bassett, Lee C

    2018-04-23

    Nanodiamonds containing nitrogen-vacancy (NV) centers offer a versatile platform for sensing applications spanning from nanomagnetism to in vivo monitoring of cellular processes. In many cases, however, weak optical signals and poor contrast demand long acquisition times that prevent the measurement of environmental dynamics. Here, we demonstrate the ability to perform fast, high-contrast optical measurements of charge distributions in ensembles of NV centers in nanodiamonds and use the technique to improve the spin-readout signal-to-noise ratio through spin-to-charge conversion. A study of 38 nanodiamonds with sizes ranging between 20 and 70 nm, each hosting a small ensemble of NV centers, uncovers complex, multiple time scale dynamics due to radiative and nonradiative ionization and recombination processes. Nonetheless, the NV-containing nanodiamonds universally exhibit charge-dependent photoluminescence contrasts and the potential for enhanced spin readout using spin-to-charge conversion. We use the technique to speed up a T 1 relaxometry measurement by a factor of 5.

  15. Propagation of optical vortices with fractional topological charge in free space

    Science.gov (United States)

    Ali, Tamelia; Kreminska, Liubov; Golovin, Andrii B.; Crouse, David T.

    2014-10-01

    The behavior of the optical vortices with fractional topological charges in the far-field is assessed through numerical modeling and confirmed by experimental results. The generation of fractional topological charge variations of the phase within a Gaussian beam was achieved by using a liquid crystal spatial light modulator (LCoS SLM). It is shown that a laser beam carrying an optical vortex with a fractional topological charge evolves into a beam with a topological charge of integer value, specifically an integer value closer to the fractional number in the far field. A potential application of this work is for data transmission within optical telecommunication systems.

  16. Electro-Optic Sampling of Transient Electric Fields from Charged Particle Beams

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, Michael James [Rochester U.

    2000-01-01

    The passage of a relativistic charged particle beam bunch through a structure is accompanied by transient electromagnetic fields. By causality, these fields must be behind the bunch, and are called "wakefields." The wakefields act back on the beam, and cause instabilities such as the beam break-up instability, and the headtail instability, which limit the luminosity of linear colliders. The wakefields are particularly important for short bunches with high charge. A great deal of effort is devoted to analytical and numerical calculations of wakefields, and wakefield effects. Experimental numbers are needed. In this thesis, we present measurements of the transient electric fields induced by a short high-charge electron bunch passing through a 6-way vacuum cross. These measurements are performed in the time domain using electro-optic sampling with a time resolution of approximately 5 picoseconds. With different orientations of the electro-optic crystal, we have measured different vector components of the electric field. The Fourier transform of the time-domain data yields the product of the beam impedance with the excitation spectrum of the bunch. Since the bunch length is known from streak camera measurements, the k loss factor is directly obtained. There is reasonably good agreement between the experimental k loss factor with calculations from the code MAFIA. To our knowledge, this is the first direct measurement of the k loss factor for bunch lengths shorter than one millimeter ( nns). We also present results of magnetic bunch compression (using a dipole chicane) of a high-charge photoinjector beam for two different UV laser pulse lengths on the pholocalhode. Al best compression, a 13.87 nC bunch was compressed to 0.66 mm (2.19 ps) rms, or a peak current of 3 kA. Other results from the photoinjeclor are given, and the laser system for pholocalhode excitation and electro-optic sampling is described.

  17. Controlling the net charge on a nanoparticle optically levitated in vacuum

    Science.gov (United States)

    Frimmer, Martin; Luszcz, Karol; Ferreiro, Sandra; Jain, Vijay; Hebestreit, Erik; Novotny, Lukas

    2017-06-01

    Optically levitated nanoparticles in vacuum are a promising model system to test physics beyond our current understanding of quantum mechanics. Such experimental tests require extreme control over the dephasing of the levitated particle's motion. If the nanoparticle carries a finite net charge, it experiences a random Coulomb force due to fluctuating electric fields. This dephasing mechanism can be fully excluded by discharging the levitated particle. Here, we present a simple and reliable technique to control the charge on an optically levitated nanoparticle in vacuum. Our method is based on the generation of charges in an electric discharge and does not require additional optics or mechanics close to the optical trap.

  18. Microscopic kinetic analysis of space-charge induced optical microbunching in a relativistic electron beam

    Directory of Open Access Journals (Sweden)

    Agostino Marinelli

    2010-11-01

    Full Text Available Longitudinal space-charge forces from density fluctuations generated by shot noise can be a major source of microbunching instability in relativistic high brightness electron beams. The gain in microbunching due to this effect is broadband, extending at least up to optical frequencies, where the induced structure on the beam distribution gives rise to effects such as coherent optical transition radiation. In the high-frequency regime, theoretical and computational analyses of microbunching formation require a full three-dimensional treatment. In this paper we address the problem of space-charge induced optical microbunching formation in the high-frequency limit when transverse thermal motion due to finite emittance is included for the first time. We derive an analytical description of this process based on the beam’s plasma dielectric function. We discuss the effect of transverse temperature on the angular distribution of microbunching gain and its connection to the physics of Landau damping in longitudinal plasma oscillations. Application of the theory to a relevant experimental scenario is discussed. The analytical results obtained are then compared to the predictions arising from high resolution three-dimensional molecular dynamics simulations.

  19. Optical absorption in silicon layers in the presence of charge inversion/accumulation or ion implantation

    International Nuclear Information System (INIS)

    Alloatti, L.; Lauermann, M.; Koos, C.; Freude, W.; Sürgers, C.; Leuthold, J.

    2013-01-01

    We determine the optical losses in gate-induced charge accumulation/inversion layers at a Si/SiO 2 interface. Comparison between gate-induced charge layers and ion-implanted thin silicon films having an identical sheet resistance shows that optical losses can be significantly lower for gate-induced layers. For a given sheet resistance, holes produce higher optical loss than electrons. Measurements have been performed at λ = 1550 nm

  20. High sensitivity optical molecular imaging system

    Science.gov (United States)

    An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

    2018-02-01

    Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

  1. Highly charged cyanine fluorophores for trafficking scaffold degradation

    International Nuclear Information System (INIS)

    Owens, Eric A; Alyabyev, Sergey; Henary, Maged; Hyun, Hoon; Kim, Soon Hee; Lee, Jeong Heon; Park, GwangLi; Ashitate, Yoshitomo; Choi, Jungmun; Hong, Gloria H; Choi, Hak Soo; Lee, Sang Jin; Khang, Gilson

    2013-01-01

    Biodegradable scaffolds have been extensively used in the field of tissue engineering and regenerative medicine. However, noninvasive monitoring of in vivo scaffold degradation is still lacking. In order to develop a real-time trafficking technique, a series of meso-brominated near-infrared (NIR) fluorophores were synthesized and conjugated to biodegradable gelatin scaffolds. Since the pentamethine cyanine core is highly lipophilic, the side chain of each fluorophore was modified with either quaternary ammonium salts or sulfonate groups. The physicochemical properties such as lipophilicity and net charge of fluorophores played a key role in the fate of NIR-conjugated scaffolds in vivo after biodegradation. The positively charged fluorophore-conjugated scaffold fragments were found in salivary glands, lymph nodes, and most of the hepatobiliary excretion route. However, halogenated fluorophores intensively accumulated into lymph nodes and the liver. Interestingly, balanced-charged gelatin scaffolds were degraded into urine in a short period of time. These results demonstrate that the noninvasive optical imaging using NIR fluorophores can be useful for the translation of biodegradable scaffolds into the clinic. (paper)

  2. High heat load synchrotron optics

    International Nuclear Information System (INIS)

    Mills, D.M.

    1993-01-01

    Third generation synchrotron radiation sources currently being constructed worldwide will produce x-ray beams of unparalleled power and power density. These high heat fluxes coupled with the stringent dimensional requirements of the x-ray optical components pose a prodigious challenge to designers of x-ray optical elements, specifically x-ray mirrors and crystal monochromators. Although certain established techniques for the cooling of high heat flux components can be directly applied to this problem, the thermal management of high heat load x-ray optical components has several unusual aspects that may ultimately lead to unique solutions. This manuscript attempts to summarize the various approaches currently being applied to this undertaking and to point out the areas of research that require further development

  3. High speed auto-charging system for condenser bank

    International Nuclear Information System (INIS)

    Mizuno, Yasunori; Bito, Fumio; Fujita, Kazuhiko; Sometani, Taro

    1987-01-01

    A current-control type high-speed charging system, which is intended for auto-charging of the condenser bank, is developed. Moreover, the system can also serve to compensate the current leakage from the condenser bank so that the charged voltage can be kept constant. The system consists of a sequence circuit, a charging current control circuit (or auto-charging circuit) and a charging circuit. The auto-charging circuit is characterized by the use of a triac to control the current. The current, controlled by the circuit, is supplied to the condenser bank through a step-up transformer and voltage doubler rectifier circuit. It is demonstrated that the use of the high-speed auto-charging circuit can largely decrease the required charging time, compared to constant voltage charging. In addition, the compensation function is shown to serve effectively for maintaining a constant voltage after the completion of charging. The required charging time is decreases as the charging current increases. The maximum charging current is decided by the rating of the traic and the current rating of the rectifier diode in the secondary circuit. Major components of these circuits have decreased impedances to minimize the effect of noise, so that the possibility of an accident can be eliminated. Other various improvements are made in the grounding circuit and the charging protection circuit in order to ensure safety. (Nogami, K.)

  4. Production of High-Intensity, Highly Charged Ions

    CERN Document Server

    Gammino, S.

    2013-12-16

    In the past three decades, the development of nuclear physics facilities for fundamental and applied science purposes has required an increasing current of multicharged ion beams. Multiple ionization implies the formation of dense and energetic plasmas, which, in turn, requires specific plasma trapping configurations. Two types of ion source have been able to produce very high charge states in a reliable and reproducible way: electron beam ion sources (EBIS) and electron cyclotron resonance ion sources (ECRIS). Multiple ionization is also obtained in laser-generated plasmas (laser ion sources (LIS)), where the high-energy electrons and the extremely high electron density allow step-by-step ionization, but the reproducibility is poor. This chapter discusses the atomic physics background at the basis of the production of highly charged ions and describes the scientific and technological features of the most advanced ion sources. Particular attention is paid to ECRIS and the latest developments, since they now r...

  5. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    Trebus, U.E.

    1989-01-01

    An experiment is described to study highly charged recoil ions on-line to the heavy accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy-ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q = 15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q = 4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q = 6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix

  6. Production, transport and charge capture measurements of highly charged recoil ions

    International Nuclear Information System (INIS)

    Trebus, U.E.

    1989-05-01

    An experiment is described to study highly charged recoil ions on-line to the heavy ion accelerator UNILAC at GSI. The highly charged recoil ions are produced by heavy ion bombardment of a gas target. Subsequently the slow highly charged recoil ions are extracted from the ionization volume, and guided through a beam transport line to a Wien filter for charge state selection and to a collision region to study charge transfer processes. Several experiments were carried out to show the efficient charge state separation. Charge states up to q=15 were observed. When using a retarding field analyzer cross sections for single electron capture were determined for different charge states of Xe q+ for q=4 to 11 and He gas. The experiments demonstrated increasing charge transfer cross sections with increasing charge state q and indicated the effect of near resonant charge capture for q=6. The flexible data acquisition system used, is described and other future experiments, such as for instance in flight ion-trapping are indicated in the appendix. (orig.)

  7. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, Michael F.; Bruhwiler, David L.

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach

  8. High-order space charge effects using automatic differentiation

    International Nuclear Information System (INIS)

    Reusch, M.F.; Bruhwiler, D.L.; Computer Accelerator Physics Conference Williamsburg, Virginia 1996)

    1997-01-01

    The Northrop Grumman Topkark code has been upgraded to Fortran 90, making use of operator overloading, so the same code can be used to either track an array of particles or construct a Taylor map representation of the accelerator lattice. We review beam optics and beam dynamics simulations conducted with TOPKARK in the past and we present a new method for modeling space charge forces to high-order with automatic differentiation. This method generates an accurate, high-order, 6-D Taylor map of the phase space variable trajectories for a bunched, high-current beam. The spatial distribution is modeled as the product of a Taylor Series times a Gaussian. The variables in the argument of the Gaussian are normalized to the respective second moments of the distribution. This form allows for accurate representation of a wide range of realistic distributions, including any asymmetries, and allows for rapid calculation of the space charge fields with free space boundary conditions. An example problem is presented to illustrate our approach. copyright 1997 American Institute of Physics

  9. Specific optical signalling of anions via intramolecular charge transfer pathway based on acridinedione fluorophore

    International Nuclear Information System (INIS)

    Thiagarajan, Viruthachalam; Ramamurthy, Perumal

    2007-01-01

    We present a simple but highly specific acridinedione fluorophore (ADD-1) that acts both as a fluorescent and colorimetric sensor for anions in acetonitrile. The specific optical signalling of ADD-1 is due to the formation of new distinct intramolecular charge transfer (ICT) emitting states in the presence of AcO - (490 nm), H 2 PO 4 - (440 nm), and F - (510 nm) over other anions. Presence of F - shows a colour change that is perceptible to the naked eye, from colourless to an intense fluorescent green due to the deprotonation of acridinedione ring amino hydrogen

  10. High accuracy ion optics computing

    International Nuclear Information System (INIS)

    Amos, R.J.; Evans, G.A.; Smith, R.

    1986-01-01

    Computer simulation of focused ion beams for surface analysis of materials by SIMS, or for microfabrication by ion beam lithography plays an important role in the design of low energy ion beam transport and optical systems. Many computer packages currently available, are limited in their applications, being inaccurate or inappropriate for a number of practical purposes. This work describes an efficient and accurate computer programme which has been developed and tested for use on medium sized machines. The programme is written in Algol 68 and models the behaviour of a beam of charged particles through an electrostatic system. A variable grid finite difference method is used with a unique data structure, to calculate the electric potential in an axially symmetric region, for arbitrary shaped boundaries. Emphasis has been placed upon finding an economic method of solving the resulting set of sparse linear equations in the calculation of the electric field and several of these are described. Applications include individual ion lenses, extraction optics for ions in surface analytical instruments and the design of columns for ion beam lithography. Computational results have been compared with analytical calculations and with some data obtained from individual einzel lenses. (author)

  11. High charge state heavy ion production from a PIG source

    International Nuclear Information System (INIS)

    Bex, L.; Clark, D.J.; Ellsworth, C.E.; Flood, W.S.; Gough, R.A.; Holley, W.R.; Meriwether, J.R.; Morris, D.

    1975-03-01

    The comparison of pulsed vs. dc arc operation for nitrogen and argon shows a shift in charge distribution toward the higher charge states for the pulsed case. Tests with various magnetic field shapes along the arc column show a significant increase in high charge state output for a uniform field compared to the case with a field low at the cathodes. (U.S.)

  12. High Availability in Optical Networks

    Science.gov (United States)

    Grover, Wayne D.; Wosinska, Lena; Fumagalli, Andrea

    2005-09-01

    Call for Papers: High Availability in Optical Networks Submission Deadline: 1 January 2006 The Journal of Optical Networking (JON) is soliciting papers for a feature Issue pertaining to all aspects of reliable components and systems for optical networks and concepts, techniques, and experience leading to high availability of services provided by optical networks. Most nations now recognize that telecommunications in all its forms -- including voice, Internet, video, and so on -- are "critical infrastructure" for the society, commerce, government, and education. Yet all these services and applications are almost completely dependent on optical networks for their realization. "Always on" or apparently unbreakable communications connectivity is the expectation from most users and for some services is the actual requirement as well. Achieving the desired level of availability of services, and doing so with some elegance and efficiency, is a meritorious goal for current researchers. This requires development and use of high-reliability components and subsystems, but also concepts for active reconfiguration and capacity planning leading to high availability of service through unseen fast-acting survivability mechanisms. The feature issue is also intended to reflect some of the most important current directions and objectives in optical networking research, which include the aspects of integrated design and operation of multilevel survivability and realization of multiple Quality-of-Protection service classes. Dynamic survivable service provisioning, or batch re-provisioning is an important current theme, as well as methods that achieve high availability at far less investment in spare capacity than required by brute force service path duplication or 100% redundant rings, which is still the surprisingly prevalent practice. Papers of several types are envisioned in the feature issue, including outlook and forecasting types of treatments, optimization and analysis, new

  13. Highly-correlated charges in polyelectrolyte gels

    Science.gov (United States)

    Sing, Charles; Zwanikken, Johannes; Olvera de La Cruz, Monica

    2013-03-01

    Polyelectrolyte gels are ubiquitous in polymer physics due to their attractive combination of structural and chemical features that permit the realization of ``environmentally responsive'' systems. The conventional conceptual picture of the volume response of these systems is based on a competition between osmotic and elastic effects. We elaborate on this fundamental understanding by including ion correlations through the use of liquid-state integral equation theory. This allows for a statistical mechanical representation of the state of the system that not only surpasses traditional Poisson-Boltzmann theories but also renders structural features in a highly accurate fashion. In particular, the local ion structure is elucidated, allowing for detailed articulation of charge inversion and condensation effects in the context of gel swelling. The inclusion of correlations has a number of ramifications that become apparent, with enhanced gel collapse and excluded volume competitions that give rise to novel and ion-dependent reentrant swelling effects. We expect this rigorous theory to prove instructive in understanding any number of gelated structures, such as chromosomes or designed synthetic materials for drug delivery.

  14. One-and two-dimensional topological charge distributions in stochastic optical fields

    CSIR Research Space (South Africa)

    Roux, FS

    2011-06-01

    Full Text Available The presentation on topological charge distributions in stochastic optical fields concludes that by using a combination of speckle fields one can produce inhomogeneous vortex distributions that allow both analytical calculations and numerical...

  15. Cold highly charged ions in a cryogenic Paul trap

    Energy Technology Data Exchange (ETDEWEB)

    Versolato, O. O., E-mail: oscar.versolato@mpi-hd.mpg.de; Schwarz, M.; Windberger, A.; Ullrich, J. [Max-Planck-Institut fuer Kernphysik (Germany); Schmidt, P. O. [Physikalisch-Technische Bundesanstalt (Germany); Drewsen, M. [University of Aarhus, Department of Physics and Astronomy (Denmark); Crespo Lopez-Urrutia, J. R. [Max-Planck-Institut fuer Kernphysik (Germany)

    2013-03-15

    Narrow optical transitions in highly charged ions (HCIs) are of particular interest for metrology and fundamental physics, exploiting the high sensitivity of HCIs to new physics. The highest sensitivity for a changing fine structure constant ever predicted for a stable atomic system is found in Ir{sup 17 + }. However, laser spectroscopy of HCIs is hindered by the large ({approx} 10{sup 6} K) temperatures at which they are produced and trapped. An unprecedented improvement in such laser spectroscopy can be obtained when HCIs are cooled down to the mK range in a linear Paul trap. We have developed a cryogenic linear Paul trap in which HCIs will be sympathetically cooled by {sup 9}Be{sup + } ions. Optimized optical access for laser light is provided while maintaining excellent UHV conditions. The Paul trap will be connected to an electron beam ion trap (EBIT) which is able to produce a wide range of HCIs. This EBIT will also provide the first experimental input needed for the determination of the transition energies in Ir{sup 17 + }, enabling further laser-spectroscopic investigations of this promising HCI.

  16. High Intensity High Charge State ECR Ion Sources

    CERN Document Server

    Leitner, Daniela

    2005-01-01

    The next-generation heavy ion beam accelerators such as the proposed Rare Isotope Accelerator (RIA), the Radioactive Ion Beam Factory at RIKEN, the GSI upgrade project, the LHC-upgrade, and IMP in Lanzhou require a great variety of high charge state ion beams with a magnitude higher beam intensity than currently achievable. High performance Electron Cyclotron Resonance (ECR) ion sources can provide the flexibility since they can routinely produce beams from hydrogen to uranium. Over the last three decades, ECR ion sources have continued improving the available ion beam intensities by increasing the magnetic fields and ECR heating frequencies to enhance the confinement and the plasma density. With advances in superconducting magnet technology, a new generation of high field superconducting sources is now emerging, designed to meet the requirements of these next generation accelerator projects. The talk will briefly review the field of high performance ECR ion sources and the latest developments for high intens...

  17. Plan charge exchange scattering at high energies

    International Nuclear Information System (INIS)

    Saleem, M.; Bhatti, S.; Fazal-e-Aleem; Rafique, M.

    1980-01-01

    By a phenomenological choice of the residue functions, a very good fit with experiment for the pion-nucleon charge exchange reaction at Fermilab energies is obtained on a simple Regge-pole model using a quadratic rho trajectory and energy-independent parameters

  18. High resolution optical DNA mapping

    Science.gov (United States)

    Baday, Murat

    Many types of diseases including cancer and autism are associated with copy-number variations in the genome. Most of these variations could not be identified with existing sequencing and optical DNA mapping methods. We have developed Multi-color Super-resolution technique, with potential for high throughput and low cost, which can allow us to recognize more of these variations. Our technique has made 10--fold improvement in the resolution of optical DNA mapping. Using a 180 kb BAC clone as a model system, we resolved dense patterns from 108 fluorescent labels of two different colors representing two different sequence-motifs. Overall, a detailed DNA map with 100 bp resolution was achieved, which has the potential to reveal detailed information about genetic variance and to facilitate medical diagnosis of genetic disease.

  19. Si/SiC heterojunction optically controlled transistor with charge compensation layer

    Directory of Open Access Journals (Sweden)

    Pu Hongbin

    2016-01-01

    Full Text Available A novel n-SiC/p-Si/n-Si optically controlled transistor with charge compensation layer has been studied in the paper. The performance of the device is simulated using Silvaco Atlas tools, which indicates excellent performances of the device in both blocking state and conducting state. The device also has a good switching characteristic with 0.54μs as rising time and 0.66μs as falling time. With the charge compensation layer, the breakdown voltage and the spectral response intensity of the device are improved by 90V and 33A/W respectively. Compared with optically controlled transistor without charge compensation layer, the n-SiC/p-Si/n-Si optically controlled transistor with charge compensation layer has a better performance.

  20. Space-charge compensation of highly charged ion beam from laser ion source

    International Nuclear Information System (INIS)

    Kondrashev, S.A.; Collier, J.; Sherwood, T.R.

    1996-01-01

    The problem of matching an ion beam delivered by a high-intensity ion source with an accelerator is considered. The experimental results of highly charged ion beam transport with space-charge compensation by electrons are presented. A tungsten thermionic cathode is used as a source of electrons for beam compensation. An increase of ion beam current density by a factor of 25 is obtained as a result of space-charge compensation at a distance of 3 m from the extraction system. The process of ion beam space-charge compensation, requirements for a source of electrons, and the influence of recombination losses in a space-charge-compensated ion beam are discussed. (author)

  1. High speed all optical networks

    Science.gov (United States)

    Chlamtac, Imrich; Ganz, Aura

    1990-01-01

    An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. The first solution to wavelength division multiplexing (WDM) based WAN networks that overcomes this limitation is presented. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs. The principle of the Lightnet architecture is the construction and use of virtual topology networks, embedded in the original network in the wavelength domain. For this construction Lightnets utilize the new concept of lightpaths which constitute the links of the virtual topology. Lightpaths are all-optical, multihop, paths in the network that allow data to be switched through intermediate nodes using high throughput passive optical switches. The use of the virtual topologies and the associated switching design introduce a number of new ideas, which are discussed in detail.

  2. Optics assembly for high power laser tools

    Science.gov (United States)

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  3. Quantum aspects of charged-particle beam optics

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Sameen Ahmed, E-mail: rohelakhan@yahoo.com [Department of Mathematics and Sciences, College of Arts and Applied Sciences, Dhofar University, Salalah, Sultanate of Oman (Oman)

    2016-06-10

    The classical treatments have been successful in designing numerous charged-particle devices. It is natural to develop a quantum prescription, since all systems are fundamentally quantum mechanical in nature. The quantum theory leads to new insights accompanied with wavelength-dependent contributions. The action of a magnetic quadrupole is derived from the Dirac equation.

  4. Optical absorption of charged excitons in semiconducting carbon nanotubes

    DEFF Research Database (Denmark)

    Rønnow, Troels Frimodt; Pedersen, Thomas Garm; Cornean, Horia

    2012-01-01

    In this article we examine the absorption coefficient of charged excitons in carbon nanotubes. We investigate the temperature and damping dependence of the absorption spectra. We show that the trion peak in the spectrum is asymmetric for temperatures greater than approximately 1 K whereas...

  5. Advancing High Contrast Adaptive Optics

    Science.gov (United States)

    Ammons, M.; Poyneer, L.; GPI Team

    2014-09-01

    A long-standing challenge has been to directly image faint extrasolar planets adjacent to their host suns, which may be ~1-10 million times brighter than the planet. Several extreme AO systems designed for high-contrast observations have been tested at this point, including SPHERE, Magellan AO, PALM-3000, Project 1640, NICI, and the Gemini Planet Imager (GPI, Macintosh et al. 2014). The GPI is the world's most advanced high-contrast adaptive optics system on an 8-meter telescope for detecting and characterizing planets outside of our solar system. GPI will detect a previously unstudied population of young analogs to the giant planets of our solar system and help determine how planetary systems form. GPI employs a 44x44 woofer-tweeter adaptive optics system with a Shack-Hartmann wavefront sensor operating at 1 kHz. The controller uses Fourier-based reconstruction and modal gains optimized from system telemetry (Poyneer et al. 2005, 2007). GPI has an apodized Lyot coronal graph to suppress diffraction and a near-infrared integral field spectrograph for obtaining planetary spectra. This paper discusses current performance limitations and presents the necessary instrumental modifications and sensitivity calculations for scenarios related to high-contrast observations of non-sidereal targets.

  6. Concept for high-charge-state ion induction accelerators

    International Nuclear Information System (INIS)

    Logan, B.G.; Perry, M.D.; Caporaso, G.J.

    1996-01-01

    This work describes a particular concept for ion induction linac accelerators using high-charge-state ions produced by an intense, short pulse laser, and compares the costs of a modular driver system producing 6.5 MJ for a variety of ion masses and charge states using a simple but consistent cost model

  7. Charged dust in planetary magnetospheres: Hamiltonian dynamics and numerical simulations for highly charged grains

    Science.gov (United States)

    Schaffer, L.; Burns, J. A.

    1994-01-01

    We use a combination of analytical and numerical methods to investigate the dynamics of charged dust grains in planetary magnetospheres. Our emphasis is on obtaining results valid for particles that are not necessarily dominated either by gravitational or electromagnetic forces. A Hamiltonian formulation of the problem yields exact results, for all values of charge-to-mass ratio, when we introduce two constraints: particles remain in the equatorial plane and the magnetic field is taken as axially symmetric. In particular, we obtain locations of equilibrium points, the frequencies of stable periodic orbits, the topology of separatrices in phase space, and the rate of longitudinal drift. These results are significant for specific applications: motion in the nearly aligned dipolar field of Saturn, and the trajectories of arbitrarily charged particles in complex magnetic fields for limited periods of time after ejection from parent bodies. Since the model is restrictive, we also use numerical integrations of the full three-dimensional equations of motion and illustrate under what conditions the constrained problem yields reasonable results. We show that a large fraction of the intermediately charged and highly charged (gyrating) particles will always be lost to a planet's atmosphere within a few hundred hours, for motion through tilted-dipole magnetic fields. We find that grains must have a very high charge-to-mass ratio in order to be mirrored back to the ring plane. Thus, except perhaps at Saturn where the dipole tilt is very small, the likely inhabitants of the dusty ring systems are those particles that are either nearly Keplerian (weakly charged) grains or grains whose charges place them in the lower end of the intermediate charge zone. Fianlly, we demonstrate the effect of plasma drag on the orbits of gyrating particles to be a rapid decrease in gyroradius followed by a slow radial evolution of the guiding center.

  8. Charge Exchange of Highly Charged Ne and Mg Ions with H and He

    Science.gov (United States)

    Lyons, D.; Cumbee, R. S.; Stancil, P. C.

    2017-10-01

    Cross sections for single electron capture (SEC), or charge exchange (CX), in collisions of Ne(8-10)+ and Mg(8-12)+ with H and He, are computed using an approximate multichannel Landau-Zener (MCLZ) formalism. Final-state-resolved cross sections for the principal (n), orbital angular momentum (ℓ), and where appropriate, total spin angular momentum (S) quantum numbers are explicitly computed, except for the incident bare ions Ne10+ and Mg12+. In the latter two cases, n{\\ell }-resolution is obtained from analytical ℓ-distribution functions applied to n-resolved MCLZ cross sections. In all cases, the cross sections are computed over the collision energy range 1 meV/u to 50 keV/u with LZ parameters estimated from atomic energies obtained from experiment, theory, or, in the case of high-lying Rydberg levels, estimated with a quantum defect approach. Errors in the energy differences in the adiabatic potentials at the avoided crossing distances give the largest contribution to the uncertainties in the cross sections, which are expected to increase with decreasing cross section magnitude. The energy differences are deduced here with the Olson-Salop-Tauljberg radial coupling model. Proper selection of an ℓ-distribution function for bare ion collisions introduces another level of uncertainty into the results. Comparison is made to existing experimental or theoretical results when available, but such data are absent for most considered collision systems. The n{\\ell }S-resolved SEC cross sections are used in an optically thin cascade simulation to predict X-ray spectra and line ratios that will aid in modeling the X-ray emission in environments where CX is an important mechanism. Details on a MCLZ computational package, Stueckelberg, are also provided.

  9. A high charge state heavy ion beam source for HIF

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.

    1995-04-01

    A high current low emittance high charge state heavy ion beam source is being developed. This is designed to deliver HIF (heavy ion fusion) driver accelerator scale beam. Using high-charge-state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system which consists of the gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 2D beam envelope simulations and experimental feasibility studies' results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector

  10. Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

    International Nuclear Information System (INIS)

    Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

    2011-01-01

    The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

  11. Optically induced charge transport in mesoscopic semiconductor systems; Optisch induzierter Ladungstransport in mesoskopischen Halbleitersystemen

    Energy Technology Data Exchange (ETDEWEB)

    Hof, Klaus-Dieter

    2009-07-13

    In the framework of this thesis optoelectronic processes in a to a quantum-dot contact nanostructured heterostructure were studied. In the experiment thereby by means of a laser in a 2DES heterostructure charge carriers were optically induced in the neighbourhood of a quantum-dot contact. Thereafter their effect on the electronic transport through the quantum-dot contact in the sample is studied. In the planely etched samples the purely electronic conductivity measurements indicate with the conductivity stages a one-dimensional subband quantization. The energetic distance of the subband bottoms amounts up to 5 meV. Furthermore the measurement in the magnetic field shows a transition of the subband structure over magnetoelectric bands to the pure Landau quantization. First photoresponse measurement s show under illumination the effect of an unwanted parallel conductivity. This effect can be suppressed by changed sample design and optimized wafer material. By this photoresponse measurements on the free-sttanding bridge samples and planely etched qunatum-dot contact samples. In low-frequency photoresponse measurements in both sample types the effect of an optically induced conductivity change can be identified. A simple model of the optically induced photoconductivity is introduced, which shows in the framework of a numerical simulation a very good agreement with the measurement data and allows the identification of the experimentally determined time constant. By application of for radiofrequencies suited components the experiment can be performed also at higher-frequent modulation of the optical excitation. Thereby it was proved that the effect of the photoinduced conductivity change because of its relatively high time constant generates for excitations in the MHz range a quasi-static conductivity state and the sample conductivity experiences therefore on a fast time scale no change.

  12. Novel silica surface charge density mediated control of the optical properties of embedded optically active materials and its application for fiber optic pH sensing at elevated temperatures.

    Science.gov (United States)

    Wang, Congjun; Ohodnicki, Paul R; Su, Xin; Keller, Murphy; Brown, Thomas D; Baltrus, John P

    2015-02-14

    Silica and silica incorporated nanocomposite materials have been extensively studied for a wide range of applications. Here we demonstrate an intriguing optical effect of silica that, depending on the solution pH, amplifies or attenuates the optical absorption of a variety of embedded optically active materials with very distinct properties, such as plasmonic Au nanoparticles, non-plasmonic Pt nanoparticles, and the organic dye rhodamine B (not a pH indicator), coated on an optical fiber. Interestingly, the observed optical response to varying pH appears to follow the surface charge density of the silica matrix for all the three different optically active materials. To the best of our knowledge, this optical effect has not been previously reported and it appears universal in that it is likely that any optically active material can be incorporated into the silica matrix to respond to solution pH or surface charge density variations. A direct application of this effect is for optical pH sensing which has very attractive features that can enable minimally invasive, remote, real time and continuous distributed pH monitoring. Particularly, as demonstrated here, using highly stable metal nanoparticles embedded in an inorganic silica matrix can significantly improve the capability of pH sensing in extremely harsh environments which is of increasing importance for applications in unconventional oil and gas resource recovery, carbon sequestration, water quality monitoring, etc. Our approach opens a pathway towards possible future development of robust optical pH sensors for the most demanding environmental conditions. The newly discovered optical effect of silica also offers the potential for control of the optical properties of optically active materials for a range of other potential applications such as electrochromic devices.

  13. Charge ordering phenomena in high temperature superconductors

    International Nuclear Information System (INIS)

    Tassini, Leonardo; Prestel, Wolfgang; Hackl, Rudi; Erb, Andreas; Lambacher, Michael

    2007-01-01

    The electronic Raman effect has been studied in single crystals of Y 1-x Ca x Ba 2 Cu 3 O 6 (Y-123) and La 2-x Sr x CuO 4 (LSCO) at different doping. The experimental results provide evidences of an anomalous contribution to the response at low energies and temperatures. In LSCO the additional excitation is in B 2g symmetry for x = 0.02 and in B 1g symmetry for x = 0.10. In Y-123, we observed the additional feature in B 2g symmetry at 1.5% doping. Mainly on the basis of the selection rules we conclude that the additional peaks are the response of a dynamical charge modulation (stripes) in the two-dimensional CuO 2 planes. The selection rules allow us to determine the orientation of the stripes to be along the diagonal of the CuO 2 planes in Y-123 and LSCO at x = 0.02, and along the principal axes in LSCO at x = 0.10

  14. Novel charge sensitive preamplifier without high-value feedback resistor

    International Nuclear Information System (INIS)

    Xi Deming

    1992-01-01

    A novel charge sensitive preamplifier is introduced. The method of removing the high value feedback resistor, the circuit design and analysis are described. A practical circuit and its measured performances are provided

  15. Improvement of highly charged ion output from an ECR source

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1995-01-01

    The physical limitations of the highly charged ion production in the ECR source is analyzed in this report. General methods to increase the output ion current and the attainable charged states of heavy ions are discussed. Some new ways to improve the output of highly charged ions from the ECR source for heavy ions are proposed. A new library of computer codes for the mathematical simulation of heavy ion production in the ECR ion source is used for numerical experiments to test these ways for improving the operation of the ECR source. (orig.)

  16. Optical engineering for high power laser applications

    International Nuclear Information System (INIS)

    Novaro, M.

    1993-01-01

    Laser facilities for Inertial Confinement Fusion (I.C.F.) experiments require laser and X ray optics able to withstand short pulse conditions. After a brief recall of high power laser system arrangements and of the characteristics of their optics, the authors will present some X ray optical developments

  17. Electron Spin Optical Orientation in Charged Quantum Dots

    Science.gov (United States)

    Shabaev, A.; Gershoni, D.; Korenev, V. L.

    2005-03-01

    We present a theory of nonresonant optical orientation of electron spins localized in quantum dots. This theory explains the negative circularly polarized photoluminescence of singlet trions localized in quantum dots previously observed in experiments where trion polarization changed to negative with time and where the degree of the negative polarization increased with intensity of pumping light. We have shown that this effect can be explained by the accumulation of dark excitons that occurs due to the spin blocking of the singlet trion formation - the major mechanism of dark exciton recombination. The accumulation of dark excitons results from a lack of electrons with a spin matching the exciton polarization. The electron spin lifetime is shortened by a transverse magnetic field or a temperature increase. This takes the block off the dark exciton recombination and restores the positive degree of trion polarization. The presented theory gives good agreement with experimental data.

  18. Probing the vacuum with highly charged ions

    International Nuclear Information System (INIS)

    Bottcher, C.; Strayer, M.R.

    1987-01-01

    The physics of the Fermion vacuum is briefly described, and applied to pair production in heavy ion collisions. We consider in turn low energies (<50 MeV/nucleon), intermediate energies (<5 GeV/nucleon), and ultrahigh energies such as would be produced in a ring collider. At high energies, interesting questions of Lorentz and gauge invariance arise. Finally, some applications to the structure of high Z atoms are examined. 14 refs., 11 figs

  19. Optical and electrical properties of negatively charged aluminium oxynitride films

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Kyungsoo; Jung, Sungwook; Lee, Jeoungin; Lee, Kwangsoo; Kim, Jaehong; Son, Hyukjoo [School of information and communication Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of); Yi, Junsin [School of information and communication Engineering, Sungkyunkwan University, 300 Chunchun-dong, Jangan-gu, Suwon, 440-746 (Korea, Republic of)], E-mail: yi@yurim.ac.kr

    2008-11-03

    Aluminium oxynitride (AlON) thin films were deposited by Radio Frequency (RF) magnetron sputtering on n-type silicon (Si) substrate of (100) orientation using argon (Ar) and oxygen (O{sub 2}) gases at substrate temperature of 450 {sup o}C. To know the change in electrical properties with gases ratio, a deposition was carried out for 140 s with Ar:O{sub 2} ratio changed from 1:3 to 4:3. After that, electrical properties of Metal-Insulator-Semiconductor (MIS) structure with AlON was analyzed. For Ar:O{sub 2} ratios from 1:3 to 4:3, all samples showed characteristics of negative charge. In particular, when Ar:O{sub 2} were 2:3 and 3:3, the value of flatband voltage in normal C-V curve showed above 14 V. The composition of the AlON in the film was investigated using X-ray Photoelectron Spectroscopy (XPS). The flatband voltages (V{sub FB}) in C-V curves were found to depend on compositions. The characteristics of photon energy band gap were obtained by UV/VIS spectrum.

  20. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  1. Atomic physics with highly charged ions

    International Nuclear Information System (INIS)

    Richard, P.

    1991-08-01

    This report discusses: One electron outer shell processes in fast ion-atom collisions; role of electron-electron interaction in two-electron processes; multi-electron processes at low energy; multi-electron processes at high energy; inner shell processes; molecular fragmentation studies; theory; and, JRM laboratory operations

  2. Atomic structure of highly-charged ions. Final report

    International Nuclear Information System (INIS)

    Livingston, A. Eugene

    2002-01-01

    Atomic properties of multiply charged ions have been investigated using excitation of energetic heavy ion beams. Spectroscopy of excited atomic transitions has been applied from the visible to the extreme ultraviolet wavelength regions to provide accurate atomic structure and transition rate data in selected highly ionized atoms. High-resolution position-sensitive photon detection has been introduced for measurements in the ultraviolet region. The detailed structures of Rydberg states in highly charged beryllium-like ions have been measured as a test of long-range electron-ion interactions. The measurements are supported by multiconfiguration Dirac-Fock calculations and by many-body perturbation theory. The high-angular-momentum Rydberg transitions may be used to establish reference wavelengths and improve the accuracy of ionization energies in highly charged systems. Precision wavelength measurements in highly charged few-electron ions have been performed to test the most accurate relativistic atomic structure calculations for prominent low-lying excited states. Lifetime measurements for allowed and forbidden transitions in highly charged few-electron ions have been made to test theoretical transition matrix elements for simple atomic systems. Precision lifetime measurements in laser-excited alkali atoms have been initiated to establish the accuracy of relativistic atomic many-body theory in many-electron systems

  3. Charge collection and charge pulse formation in highly irradiated silicon planar detectors

    International Nuclear Information System (INIS)

    Dezillie, B.; Li, Z.; Eremin, V.

    1998-06-01

    The interpretation of experimental data and predictions for future experiments for high-energy physics have been based on conventional methods like capacitance versus voltage (C-V) measurements. Experiments carried out on highly irradiated detectors show that the kinetics of the charge collection and the dependence of the charge pulse amplitude on the applied bias are deviated too far from those predicted by the conventional methods. The described results show that in highly irradiated detectors, at a bias lower than the real full depletion voltage (V fd ), the kinetics of the charge collection (Q) contains a fast and a slow component. At V = V fd *, which is the full depletion voltage traditionally determined by the extrapolation of the fast component amplitude of q versus bias to the maximum value or from the standard C-V measurements, the pulse has a slow component with significant amplitude. This slow component can only be eliminated by applying additional bias that amounts to the real full depletion voltage (V fd ) or more. The above mentioned regularities are explained in this paper in terms of a model of an irradiated detector with multiple regions. This model allows one to use C-V, in a modified way, as well as TChT (transient charge technique) measurements to determine the V fd for highly irradiated detectors

  4. Ionization of water clusters by fast Highly Charged Ions: Stability, fragmentation, energetics and charge mobility

    International Nuclear Information System (INIS)

    Legendre, S; Maisonny, R; Capron, M; Bernigaud, V; Cassimi, A; Gervais, B; Grandin, J-P; Huber, B A; Manil, B; Rousseau, P; Tarisien, M; Adoui, L; Lopez-Tarifa, P; AlcamI, M; MartIn, F; Politis, M-F; Penhoat, M A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study dissociative ionization of water clusters by impact of fast Ni ions. Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized clusters. An unusual stability of the (H 2 O) 4 H ''+ ion is observed, which could be the signature of the so called ''Eigen'' structure in gas phase water clusters. High charge mobility, responsible for the formation of protonated water clusters that dominate the mass spectrum, is evidenced. These results are supported by CPMD and TDDFT simulations, which also reveal the mechanisms of such mobility.

  5. Strong charge state dependence of H+ and H2+ sputtering induced by slow highly charged ions

    International Nuclear Information System (INIS)

    Kakutani, N.; Azuma, T.; Yamazaki, Y.; Komaki, K.; Kuroki, K.

    1995-01-01

    Secondary ion emission has been studied for very slow ( similar 0.01ν B ) highly charged Ar and N ions bombarding C 60 containing hydrogen as an impurity. It is found that the fragmentations of C 60 are very rare even for Ar 16+ bombardments. On the other hand, the sputtering of H + and H 2 + has been observed to increase drastically as a function of incident charge q like q γ (e.g., γ similar 4.6 for H + sputtering by 500 eV Ar q+ ). (orig.)

  6. Influence of negative charge on the optical properties of a silver sol

    Directory of Open Access Journals (Sweden)

    JOVAN M. NEDELJKOVIC

    2000-03-01

    Full Text Available The effects of negative charge on the optical properties of a silver sol prepared using sodium borohydride as a reductant were studied. The oscillations in the position of the maximum and the intensity of the surface plasmon absorption band were obesrved. The observed effects were explained as a consequence of the fluctuation of the density of free electrons due to the alternate charging and discharging of the silver particles. The charging process involves electron injection from borohydride ions and intermediate species formed during the course of the metal-catalyzed hydrolysis of borohydride ions (BH3OH-, BH2(OH2 and BH(OH3- into the silver particles, while discharge of the silver sol, by reduction of water to hydrogen, limits the attainable negative charge on the particles.

  7. Electron yield from Be-Cu induced by highly charged Xe q+ ions

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Láska, Leoš; Stöckli, M. P.; Fehrenbach, C. W.

    2002-01-01

    Roč. 196, - (2002), s. 61-67 ISSN 0168-583X R&D Projects: GA AV ČR IAA1010105; GA MŠk LN00A100 Institutional research plan: CEZ:AV0Z1010921 Keywords : highly charged ion-induced electron emission * angle impact effect * Be-Cu Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.158, year: 2002

  8. Semiconductor optical amplifier-based all-optical gates for high-speed optical processing

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2000-01-01

    Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulation....... These gates are very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-speed all-optical logic functions...

  9. Penning traps with unitary architecture for storage of highly charged ions

    International Nuclear Information System (INIS)

    Tan, Joseph N.; Guise, Nicholas D.; Brewer, Samuel M.

    2012-01-01

    Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two-magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

  10. Penning traps with unitary architecture for storage of highly charged ions.

    Science.gov (United States)

    Tan, Joseph N; Brewer, Samuel M; Guise, Nicholas D

    2012-02-01

    Penning traps are made extremely compact by embedding rare-earth permanent magnets in the electrode structure. Axially-oriented NdFeB magnets are used in unitary architectures that couple the electric and magnetic components into an integrated structure. We have constructed a two-magnet Penning trap with radial access to enable the use of laser or atomic beams, as well as the collection of light. An experimental apparatus equipped with ion optics is installed at the NIST electron beam ion trap (EBIT) facility, constrained to fit within 1 meter at the end of a horizontal beamline for transporting highly charged ions. Highly charged ions of neon and argon, extracted with initial energies up to 4000 eV per unit charge, are captured and stored to study the confinement properties of a one-magnet trap and a two-magnet trap. Design considerations and some test results are discussed.

  11. Resonance charge exchange mechanism at high and moderate energies

    International Nuclear Information System (INIS)

    Bogdanov, A.V.; Gevorkyan, A.S.

    1984-01-01

    Charge exchange mechanisms at high and medium energies are investigated, ta king the resonance charge exchange of a proton by an hydrogen atom as an example . It is established that there are two classical charge exchange mechanisms rel ated to direct proton knockout from the bound state and one quantum-mechanical mechanism corresponding to the electron tunnelling from one bound state to anoth er. The classical cross-section diverges for two of these mechanisms, and the quasiclassical scattering amplitude must be calculated on the base of a complex classical trajectory. Physical grounds for the choice of such trajectories are discussed and calculations of the Van Vleck determinant for these mechanisms a re presented. Contributions from different mechanisms to the total charge excha nge cross-section are analyzed. A comparison with experimental data and results of other authors is made

  12. Charged particle beam scanning using deformed high gradient insulator

    Science.gov (United States)

    Chen, Yu -Jiuan

    2015-10-06

    Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

  13. Multistage charged particle accelerator, with high-vacuum insulation

    International Nuclear Information System (INIS)

    Holl, P.

    1976-01-01

    A multistage charged-particle accelerator for operating with accelerating voltages higher than 150 kV is described. The device consists essentially of a high-voltage insulator, a source for producing charged particles, a Wehnelt cylinder, an anode, and a post-accelerating tube containing stack-wise positioned post-accelerating electrodes. A high vacuum is used for insulating the parts carrying the high voltages, and at least one cylindrical screen surrounding these parts is interposed between them and the vacuum vessel, which can itself also function as a cylindrical screen

  14. Highly charged atomic physics at HIRFL-CSR

    International Nuclear Information System (INIS)

    Ma Xinwen; Wang Youde; Hou Mingdong; Jin Gengmin

    1996-01-01

    HIRFL-CSR is a proposed electron cooling storage ring optimized to accelerate and store beams of highly charged heavy ions. Several possibilities for advanced atomic physics studies are discussed, such as studies of electron-ion, ion-atoms, photon-ion-electron interactions and high resolution spectroscopy

  15. Highly charged ions: a miniature laboratory for new fundamental science

    International Nuclear Information System (INIS)

    Gillaspy, J.D.

    2002-01-01

    Full text: Highly charged ions are 10-100 times smaller than ordinary atoms, yet they present within themselves a remarkably rich arena for testing fundamental aspects of physics. These tests are based on a precise analysis of the energy distribution of the photons that are emitted as electrons hop between energy levels within the highly charged ions. With sufficiently precise analysis, it may be possible to obtain new information about the structure of the vacuum, the effect of special relativity on many-body correlation, physics beyond the Standard Model, and the fundamental nature of quantum measurements. This talk will review the current state-of-the-art in the spectroscopy of highly charged ions, and give a look towards the future

  16. Charged-particle mutagenesis 2. Mutagenic effects of high energy charged particles in normal human fibroblasts

    Science.gov (United States)

    Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

    1994-01-01

    The biological effects of high Linear Energy Transfer (LET) charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 sq micrometer and 0.09 to 5.56 x 10(exp -3) sq micrometer respectively. The maximum values were obtained by Fe-56 with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(exp -5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

  17. Charged-particle mutagenesis II. Mutagenic effects of high energy charged particles in normal human fibroblasts

    Science.gov (United States)

    Chen, D. J.; Tsuboi, K.; Nguyen, T.; Yang, T. C.

    1994-01-01

    The biological effects of high LET charged particles are a subject of great concern with regard to the prediction of radiation risk in space. In this report, mutagenic effects of high LET charged particles are quantitatively measured using primary cultures of human skin fibroblasts, and the spectrum of induced mutations are analyzed. The LET of the charged particles ranged from 25 KeV/micrometer to 975 KeV/micrometer with particle energy (on the cells) between 94-603 MeV/u. The X-chromosome linked hypoxanthine guanine phosphoribosyl transferase (hprt) locus was used as the target gene. Exposure to these high LET charged particles resulted in exponential survival curves; whereas, mutation induction was fitted by a linear model. The Relative Biological Effect (RBE) for cell-killing ranged from 3.73 to 1.25, while that for mutant induction ranged from 5.74 to 0.48. Maximum RBE values were obtained at the LET of 150 keV/micrometer. The inactivation cross-section (alpha i) and the action cross-section for mutant induction (alpha m) ranged from 2.2 to 92.0 micrometer2 and 0.09 to 5.56 x 10(-3) micrometer2, respectively. The maximum values were obtained by 56Fe with an LET of 200 keV/micrometer. The mutagenicity (alpha m/alpha i) ranged from 2.05 to 7.99 x 10(-5) with the maximum value at 150 keV/micrometer. Furthermore, molecular analysis of mutants induced by charged particles indicates that higher LET beams are more likely to cause larger deletions in the hprt locus.

  18. Photoproduction of charged particle with high transverse momentum

    International Nuclear Information System (INIS)

    Campos Costa Ramos, S.E. de.

    1986-09-01

    Inclusive cross sections of high transverse moment charged pions induced by a high energy photon beam have been measured. These results do not account, neither in slope nor in normalisation, for the VDM component of the photon, evaluated with pion induced data taken in the same experimental conditions after VDM subtraction, excellent agreement is found with QCD calculations up to second order in α s , in an extended cinematic region, different choices of the gluon fragmentation function do not alter this conclusion. Our measures of the inclusive final state charge asymmetries also confirm QCD expectations. 42 refs [fr

  19. HITRAP: A Facility for Experiments with Trapped Highly Charged Ions

    International Nuclear Information System (INIS)

    Quint, W.; Dilling, J.; Djekic, S.; Haeffner, H.; Hermanspahn, N.; Kluge, H.-J.; Marx, G.; Moore, R.; Rodriguez, D.; Schoenfelder, J.; Sikler, G.; Valenzuela, T.; Verdu, J.; Weber, C.; Werth, G.

    2001-01-01

    HITRAP is a planned ion trap facility for capturing and cooling of highly charged ions produced at GSI in the heavy-ion complex of the UNILAC-SIS accelerators and the ESR storage ring. In this facility heavy highly charged ions up to uranium will be available as bare nuclei, hydrogen-like ions or few-electron systems at low temperatures. The trap for receiving and studying these ions is designed for operation at extremely high vacuum by cooling to cryogenic temperatures. The stored highly charged ions can be investigated in the trap itself or can be extracted from the trap at energies up to about 10 keV/q. The proposed physics experiments are collision studies with highly charged ions at well-defined low energies (eV/u), high-accuracy measurements to determine the g-factor of the electron bound in a hydrogen-like heavy ion and the atomic binding energies of few-electron systems, laser spectroscopy of HFS transitions and X-ray spectroscopy

  20. High density thermite mixture for shaped charge ordnance disposal

    Directory of Open Access Journals (Sweden)

    Tamer Elshenawy

    2017-10-01

    Full Text Available The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using cold iso-static pressing technique, which exhibited relatively high density and high burning rate thermite mixture. The produced green product compacted powder mixture was tested against small caliber shaped charge bomblet for neutralization. Theoretical and experimental results showed that the prepared thermite mixture containing 33% of aluminum as a fuel with ferric oxide can be successfully used for shaped charge ordnance disposal.

  1. Design and simulation of ion optics for ion sources for production of singly charged ions

    Science.gov (United States)

    Zelenak, A.; Bogomolov, S. L.

    2004-05-01

    During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

  2. Design and simulation of ion optics for ion sources for production of singly charged ions

    International Nuclear Information System (INIS)

    Zelenak, A.; Bogomolov, S.L.

    2004-01-01

    During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments

  3. Production of highly charged ion beams from ECR ion sources

    International Nuclear Information System (INIS)

    Xie, Z.Q.

    1997-09-01

    Electron Cyclotron Resonance (ECR) ion source development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECR ion sources. So far at cw mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ and U 34+ have been produced from ECR ion sources. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I ≥ 60 enA) also has been achieved. This article will review the ECR ion source progress and discuss key requirement for ECR ion sources to produce the highly charged ion beams

  4. Understanding optically stimulated charge movement in quartz and feldspar using time-resolved measurements

    International Nuclear Information System (INIS)

    Ankjaergaard, C.

    2010-02-01

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) from quartz and feldspar are widely used in accident dosimetry and luminescence dating. In order to improve already existing methods or to develop new methods towards extending the current limits of the technique, it is important to understand the charge movement within these materials. Earlier studies have primarily focussed on examination of the trap behaviour; however, this only tells half of the story as OSL is a combination of charge stimulation and recombination. By using time-resolved OSL (TR-OSL), one can directly examine the recombination route(s), and thus obtain insight into the other half of the process involved in luminescence emission. This thesis studies the TR-OSL and optically stimulated phosphorescence signals from quartz and feldspars spanning several orders of magnitude in time (few ns to the seconds time scale) in order to identify various charge transport mechanisms in the different time regimes. The techniques employed are time-resolved OSL, continuous-wave OSL, TL, optically stimulated exo-electron (OSE) emission and time-resolved OSE. These different techniques are used in combination with variable thermal or optical stimulation energy. The thesis first delves into three main methodological developments, namely (i) research and development of the equipment for TR-OSL measurements, (ii) finding the best method for multiple-exponential analysis of a TR-OSL curve, and (iii) optimisation of the pulsing configuration for the best separation of quartz OSL from a mixed quarts-feldspar sample. It then proceeds to study the different charge transport mechanisms subsequent to an optical stimulation pulse in quartz and feldspars. The results obtained for quartz conclude that the main lifetime component in quartz represents an excited state lifetime of the recombination centre, and the more slowly decaying components on the millisecond to seconds time scale arise from charge recycling

  5. Understanding optically stimulated charge movement in quartz and feldspar using time-resolved measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ankjaergaard, C.

    2010-02-15

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) from quartz and feldspar are widely used in accident dosimetry and luminescence dating. In order to improve already existing methods or to develop new methods towards extending the current limits of the technique, it is important to understand the charge movement within these materials. Earlier studies have primarily focussed on examination of the trap behaviour; however, this only tells half of the story as OSL is a combination of charge stimulation and recombination. By using time-resolved OSL (TR-OSL), one can directly examine the recombination route(s), and thus obtain insight into the other half of the process involved in luminescence emission. This thesis studies the TR-OSL and optically stimulated phosphorescence signals from quartz and feldspars spanning several orders of magnitude in time (few ns to the seconds time scale) in order to identify various charge transport mechanisms in the different time regimes. The techniques employed are time-resolved OSL, continuous-wave OSL, TL, optically stimulated exo-electron (OSE) emission and time-resolved OSE. These different techniques are used in combination with variable thermal or optical stimulation energy. The thesis first delves into three main methodological developments, namely (i) research and development of the equipment for TR-OSL measurements, (ii) finding the best method for multiple-exponential analysis of a TR-OSL curve, and (iii) optimisation of the pulsing configuration for the best separation of quartz OSL from a mixed quarts-feldspar sample. It then proceeds to study the different charge transport mechanisms subsequent to an optical stimulation pulse in quartz and feldspars. The results obtained for quartz conclude that the main lifetime component in quartz represents an excited state lifetime of the recombination centre, and the more slowly decaying components on the millisecond to seconds time scale arise from charge recycling

  6. Electron capture by highly charged ions from surfaces and gases

    Energy Technology Data Exchange (ETDEWEB)

    Allen, F.

    2008-01-11

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar{sup 17+} and Ar{sup 18+} ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu{sup -1}, charge-selected and then decelerated down to 5 eVu{sup -1} for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar{sup 17+} and Ar{sup 18+} ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu{sup -1}, charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar{sup 16+} and Xe{sup 44+} and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  7. Electron capture by highly charged ions from surfaces and gases

    International Nuclear Information System (INIS)

    Allen, F.

    2008-01-01

    In this study highly charged ions produced in Electron Beam Ion Traps are used to investigate electron capture from surfaces and gases. The experiments with gas targets focus on spectroscopic measurements of the K-shell x-rays emitted at the end of radiative cascades following electron capture into Rydberg states of Ar 17+ and Ar 18+ ions as a function of collision energy. The ions are extracted from an Electron Beam Ion Trap at an energy of 2 keVu -1 , charge-selected and then decelerated down to 5 eVu -1 for interaction with an argon gas target. For decreasing collision energies a shift to electron capture into low orbital angular momentum capture states is observed. Comparative measurements of the K-shell x-ray emission following electron capture by Ar 17+ and Ar 18+ ions from background gas in the trap are made and a discrepancy in the results compared with those from the extraction experiments is found. Possible explanations are discussed. For the investigation of electron capture from surfaces, highly charged ions are extracted from an Electron Beam Ion Trap at energies of 2 to 3 keVu -1 , charge-selected and directed onto targets comprising arrays of nanoscale apertures in silicon nitride membranes. The highly charged ions implemented are Ar 16+ and Xe 44+ and the aperture targets are formed by focused ion beam drilling in combination with ion beam assisted thin film deposition, achieving hole diameters of 50 to 300 nm and aspect ratios of 1:5 to 3:2. After transport through the nanoscale apertures the ions pass through an electrostatic charge state analyzer and are detected. The percentage of electron capture from the aperture walls is found to be much lower than model predictions and the results are discussed in terms of a capillary guiding mechanism. (orig.)

  8. Mean charged hadron multiplicities in high-energy collisions

    Energy Technology Data Exchange (ETDEWEB)

    Albini, E [Istituto di Matematica dell' Universita Cattolica di Brescia (Italy); Capiluppi, P; Giacomelli, G; Rossi, A M [Bologna Univ. (Italy). Istituto di Fisica

    1976-03-01

    A collection of mean charged hadron multiplicities per inelastic collision in various high-energy processes is presented. An extensive list of fits of as a function of energy is presented and discussed. As the energy increases the multiplicities for different collisions tend to a unique curve, independent of the type of colliding particles.

  9. Thermal spike analysis of highly charged ion tracks

    International Nuclear Information System (INIS)

    Karlušić, M.; Jakšić, M.

    2012-01-01

    The irradiation of material using swift heavy ion or highly charged ion causes excitation of the electron subsystem at nanometer scale along the ion trajectory. According to the thermal spike model, energy deposited into the electron subsystem leads to temperature increase due to electron–phonon coupling. If ion-induced excitation is sufficiently intensive, then melting of the material can occur, and permanent damage (i.e., ion track) can be formed upon rapid cooling. We present an extension of the analytical thermal spike model of Szenes for the analysis of surface ion track produced after the impact of highly charged ion. By applying the model to existing experimental data, more than 60% of the potential energy of the highly charged ion was shown to be retained in the material during the impact and transformed into the energy of the thermal spike. This value is much higher than 20–40% of the transferred energy into the thermal spike by swift heavy ion. Thresholds for formation of highly charged ion track in different materials show uniform behavior depending only on few material parameters.

  10. The electro-optical and charge transport study of imidazolidin derivative: Quantum chemical investigations

    Directory of Open Access Journals (Sweden)

    Ahmad Irfan

    2016-11-01

    Full Text Available Imidazolidin derivatives gained significant attention in our daily life from better biological activity to the semiconducting materials. The present investigation deals with the in depth study of (Z-2-sulfanylidene-5-(thiophen-2-ylmethylideneimidazolidin-4-one (STMI with respect to their structural, electronic, optical and charge transport properties as semiconducting material. The ground and first excited state geometries were optimized by applying density functional theory (DFT and time dependent DFT, respectively. The light has been shed on the frontier molecular orbitals (FMOs and observed comprehensible intramolecular charge transfer (ICT from the highest occupied molecular orbitals (HOMOs to the lowest unoccupied molecular orbitals (LUMOs. The absorption, emission, ionization potentials (IP, electron affinities (EA, total and partial densities of states and structure-property relationship have been discussed. Finally, hole as well as electron reorganization energies, transfer integrals and intrinsic mobilities have been calculated then charge transport behavior of STMI was discussed, intensively.

  11. Production of highly charged ion beams with SECRAL

    International Nuclear Information System (INIS)

    Sun, L. T.; Zhao, H. W.; Zhang, X. Z.; Feng, Y. C.; Li, J. Y.; Guo, X. H.; Ma, H. Y.; Zhao, H. Y.; Ma, B. H.; Wang, H.; Li, X. X.; Jin, T.; Xie, D. Z.; Lu, W.; Cao, Y.; Shang, Y.

    2010-01-01

    Superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is an all-superconducting-magnet electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged ion beams to meet the requirements of the Heavy Ion Research Facility in Lanzhou (HIRFL). To further enhance the performance of SECRAL, an aluminum chamber has been installed inside a 1.5 mm thick Ta liner used for the reduction of x-ray irradiation at the high voltage insulator. With double-frequency (18+14.5 GHz) heating and at maximum total microwave power of 2.0 kW, SECRAL has successfully produced quite a few very highly charged Xe ion beams, such as 10 e μA of Xe 37+ , 1 e μA of Xe 43+ , and 0.16 e μA of Ne-like Xe 44+ . To further explore the capability of the SECRAL in the production of highly charged heavy metal ion beams, a first test run on bismuth has been carried out recently. The main goal is to produce an intense Bi 31+ beam for HIRFL accelerator and to have a feel how well the SECRAL can do in the production of very highly charged Bi beams. During the test, though at microwave power less than 3 kW, more than 150 e μA of Bi 31+ , 22 e μA of Bi 41+ , and 1.5 e μA of Bi 50+ have been produced. All of these results have again demonstrated the great capability of the SECRAL source. This article will present the detailed results and brief discussions to the production of highly charged ion beams with SECRAL.

  12. Tetracyanidoborates with triply charged rare earth metal cations and their optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Hackbarth, Liisa

    2015-11-24

    The aim of this thesis is the description of the synthesis and characterization of a new group of tetracyanidoborates: tetracyanidoborates with trivalent rare earth metal cations. Their optical properties in the ultraviolet and visible range are also discussed. Common synthetic routes for tetracyanidoborates are adapted and applied to the preparation of the rare earth tetracyanidoborate hydrates. They are accessible with high yields and high purity through a reaction between the tetracyanidoboronic acid and rare earth hydroxides. It is shown that the rare earth tetracyanidoborates form isostructural groups, like the [LRE(H{sub 2}O){sub 5}][B(CN){sub 4}]{sub 3}.0.5 H{sub 2}O, where LRE{sup 3+} is La, Ce, Pr, Nd, Sm, Eu and Gd, the [HRE(H{sub 2}O){sub 7}][B(CN){sub 4}]{sub 3} and the [HRE(H{sub 2}O){sub 8}][B(CN){sub 4}]{sub 3}.3 H{sub 2}O, where HRE{sup 3+} is Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. Furthermore, the coordination number 9 is noticed to be common among the light rare earth cations, whereas the minor coordination number 8 is prevalent for the heavy rare earth cations in their tetracyanidoborates. This different construction of the coordination spheres between light and heavy rare earth cations leads to different structures depending on the energetic efficiency of the structural arrangement. Generally, the rare earth tetracyanidoborate hydrates are found to crystallize in the monoclinic crystal system. Moreover, other different crystal structures are observed depending on the crystallization temperature and the type of coordinated ligands and co-crystallized solvent molecules. The tetracyanidoborate hydrates with triply charged rare earth cations are characterized comprehensively by X-ray diffraction, vibrational spectroscopy, NMR-spectroscopy as well as by thermal analysis. Furthermore, the optical properties of some dehydrated rare earth tetracyanidoborates are investigated by UV-spectroscopy and luminescence measurements. The results of the optical

  13. Tetracyanidoborates with triply charged rare earth metal cations and their optical properties

    International Nuclear Information System (INIS)

    Hackbarth, Liisa

    2015-01-01

    The aim of this thesis is the description of the synthesis and characterization of a new group of tetracyanidoborates: tetracyanidoborates with trivalent rare earth metal cations. Their optical properties in the ultraviolet and visible range are also discussed. Common synthetic routes for tetracyanidoborates are adapted and applied to the preparation of the rare earth tetracyanidoborate hydrates. They are accessible with high yields and high purity through a reaction between the tetracyanidoboronic acid and rare earth hydroxides. It is shown that the rare earth tetracyanidoborates form isostructural groups, like the [LRE(H_2O)_5][B(CN)_4]_3.0.5 H_2O, where LRE"3"+ is La, Ce, Pr, Nd, Sm, Eu and Gd, the [HRE(H_2O)_7][B(CN)_4]_3 and the [HRE(H_2O)_8][B(CN)_4]_3.3 H_2O, where HRE"3"+ is Tb, Dy, Ho, Er, Tm, Yb, Lu and Y. Furthermore, the coordination number 9 is noticed to be common among the light rare earth cations, whereas the minor coordination number 8 is prevalent for the heavy rare earth cations in their tetracyanidoborates. This different construction of the coordination spheres between light and heavy rare earth cations leads to different structures depending on the energetic efficiency of the structural arrangement. Generally, the rare earth tetracyanidoborate hydrates are found to crystallize in the monoclinic crystal system. Moreover, other different crystal structures are observed depending on the crystallization temperature and the type of coordinated ligands and co-crystallized solvent molecules. The tetracyanidoborate hydrates with triply charged rare earth cations are characterized comprehensively by X-ray diffraction, vibrational spectroscopy, NMR-spectroscopy as well as by thermal analysis. Furthermore, the optical properties of some dehydrated rare earth tetracyanidoborates are investigated by UV-spectroscopy and luminescence measurements. The results of the optical measurements indicate that the tetracyanidoborates with rare earth metal cations

  14. ERC sources for the production of highly charged ions (invited)

    International Nuclear Information System (INIS)

    Lyneis, C.M.; Antaya, T.A.

    1990-01-01

    Electron cyclotron resonance ion sources (ECRIS) using rf between 5 and 16 GHz have been developed into stable, reliable sources of highly charged ions produced from a wide range of elements. These devices are currently used as ion sources for cyclotrons, synchrotrons, and heavy-ion linacs for nuclear and relativistic heavy-ion physics. They also serve the atomic physics community as a source of low energy multiply charged ions. In order to improve their performance both with respect to maximum charge state and beam intensity, ECRIS builders are now designing and constructing sources which will operate at frequencies up to 30 GHz. In this article we review the present status of operating ECRIS, review recent experimental measurements on plasma parameters, and look at the technology and potential of sources operating at frequencies up to 30 GHz

  15. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A

    1998-06-01

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1,115 MeV. At about 5 NeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted ut of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models

  16. Vacuum improvements for ultra high charge state ion acceleration

    International Nuclear Information System (INIS)

    Xie, Z.Q.; Lyneis, C.M.; Clark, D.J.; Guy, A.; Lundgren, S.A.

    1999-01-01

    The installation of a second cryo panel has significantly improved the vacuum in the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. The neutral pressure in the extraction region decreased from 1.2 x 10 -6 down to about 7 x 10 -7 Torr. The vacuum improvement reduces beam loss from charge changing collisions and enhances the cyclotron beam transmission, especially for the high charge state heavy ions. Tests with improved vacuum show the cyclotron transmission increased more than 50% (from 5.7% to 9.0%) for a Xe 27+ at 603 MeV, more than doubled for a Bi 41+ beam (from 1.9% % to 4.6%) at 904 MeV and tripled for a U 47+ beam (from 1.2% to 3.6%) at 1115 MeV. At about 5 MeV/nucleon 92 enA (2.2 pnA) for Bi 41+ and 14 enA (0.3 pnA) for U 47+ were extracted out of the 88-Inch Cyclotron Ion beams with charge states as high as U 64+ have been produced by the LBNL AECR-U ion source and accelerated through the cyclotron for the first time. The beam losses for a variety of ultra high charge state ions were measured as a function of cyclotron pressure and compared with the calculations from the existing models. (authors)

  17. Gingin High Optical Power Test Facility

    International Nuclear Information System (INIS)

    Zhao, C; Blair, D G; Barrigo, P

    2006-01-01

    The Australian Consortium for Gravitational Wave Astronomy (ACIGA) in collaboration with LIGO is developing a high optical power research facility at the AIGO site, Gingin, Western Australia. Research at the facility will provide solutions to the problems that advanced gravitational wave detectors will encounter with extremely high optical power. The problems include thermal lensing and parametric instabilities. This article will present the status of the facility and the plan for the future experiments

  18. Laser focusing of high-energy charged-particle beams

    International Nuclear Information System (INIS)

    Channell, P.J.

    1986-01-01

    It is shown that laser focusing of high-energy charged-particle beams using the inverse Cherenkov effect is well suited for applications with large linear colliders. Very high gradient (>0.5 MG/cm) lenses result that can be added sequentially without AG cancellation. These lenses are swell understood, have small geometric aberrations, and offer the possibility of correlating phase and energy aberrations to produce an achromatic final focus

  19. Optical pumping and negative luminescence polarization in charged GaAs quantum dots

    Science.gov (United States)

    Shabaev, Andrew; Stinaff, Eric A.; Bracker, Allan S.; Gammon, Daniel; Efros, Alexander L.; Korenev, Vladimir L.; Merkulov, Igor

    2009-01-01

    Optical pumping of electron spins and negative photoluminescence polarization are observed when interface quantum dots in a GaAs quantum well are excited nonresonantly by circularly polarized light. Both observations can be explained by the formation of long-lived dark excitons through hole spin relaxation in the GaAs quantum well prior to exciton capture. In this model, optical pumping of resident electron spins is caused by capture of dark excitons and recombination in charged quantum dots. Negative polarization results from accumulation of dark excitons in the quantum well and is enhanced by optical pumping. The dark exciton model describes the experimental results very well, including intensity and bias dependence of the photoluminescence polarization and the Hanle effect.

  20. A Review on Homogeneous Charge Compression Ignition and Low Temperature Combustion by Optical Diagnostics

    Directory of Open Access Journals (Sweden)

    Chao Jin

    2015-01-01

    Full Text Available Optical diagnostics is an effective method to understand the physical and chemical reaction processes in homogeneous charge compression ignition (HCCI and low temperature combustion (LTC modes. Based on optical diagnostics, the true process on mixing, combustion, and emissions can be seen directly. In this paper, the mixing process by port-injection and direct-injection are reviewed firstly. Then, the combustion chemical reaction mechanism is reviewed based on chemiluminescence, natural-luminosity, and laser diagnostics. After, the evolution of pollutant emissions measured by different laser diagnostic methods is reviewed and the measured species including NO, soot, UHC, and CO. Finally, a summary and the future directions on HCCI and LTC used optical diagnostics are presented.

  1. Electron impact ionization of highly charged lithiumlike ions

    International Nuclear Information System (INIS)

    Wong, K.L.

    1992-10-01

    Electron impact ionization cross sections can provide valuable information about the charge-state and power balance of highly charged ions in laboratory and astrophysical plasmas. In the present work, a novel technique based on x-ray measurements has been used to infer the ionization cross section of highly charged lithiumlike ions on the Livermore electron beam ion trap. In particular, a correspondence is established between an observed x ray and an ionization event. The measurements are made at one energy corresponding to approximately 2.3 times the threshold energy for ionization of lithiumlike ions. The technique is applied to the transition metals between Z=22 (titanium, Ti 19+ ) and Z=26 (iron, Fe 23+ ) and to Z=56 (barium, Ba 53+ ). The results for the transition metals, which have an estimated 17-33% uncertainty, are in good overall agreement with a relativistic distorted-wave calculation. However, less good agreement is found for barium, which has a larger uncertainty. Methods for properly accounting for the polarization in the x-ray intensities and for inferring the charge-state abundances from x-ray observations, which were developed for the ionization measurements, as well as an x-ray model that assists in the proper interpretation of the data are also presented

  2. Advanced Functionalities for Highly Reliable Optical Networks

    DEFF Research Database (Denmark)

    An, Yi

    This thesis covers two research topics concerning optical solutions for networks e.g. avionic systems. One is to identify the applications for silicon photonic devices for cost-effective solutions in short-range optical networks. The other one is to realise advanced functionalities in order...... to increase the availability of highly reliable optical networks. A cost-effective transmitter based on a directly modulated laser (DML) using a silicon micro-ring resonator (MRR) to enhance its modulation speed is proposed, analysed and experimentally demonstrated. A modulation speed enhancement from 10 Gbit...... interconnects and network-on-chips. A novel concept of all-optical protection switching scheme is proposed, where fault detection and protection trigger are all implemented in the optical domain. This scheme can provide ultra-fast establishment of the protection path resulting in a minimum loss of data...

  3. Interaction of low-energy highly charged ions with matter

    International Nuclear Information System (INIS)

    Ginzel, Rainer

    2010-01-01

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

  4. High Spectral Density Optical Communication Technologies

    CERN Document Server

    Nakazawa, Masataka; Miyazaki, Tetsuya

    2010-01-01

    The latest hot topics of high-spectral density optical communication systems using digital coherent optical fibre communication technologies are covered by this book. History and meaning of a "renaissance" of the technology, requirements to the Peta-bit/s class "new generation network" are also covered in the first part of this book. The main topics treated are electronic and optical devices, digital signal processing including forward error correction, modulation formats as well as transmission and application systems. The book serves as a reference to researchers and engineers.

  5. Design of a charge sensitive preamplifier on high resistivity silicon

    International Nuclear Information System (INIS)

    Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

    1987-01-01

    A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3μm for silicon drift detectors. 6 refs., 9 figs

  6. ACIGA's high optical power test facility

    International Nuclear Information System (INIS)

    Ju, L; Aoun, M; Barriga, P

    2004-01-01

    Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ∼10 6 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties

  7. Quantum electrodynamical effects in heavy highly-charged ions

    International Nuclear Information System (INIS)

    Yerokhin, V.A.; Artemyev, A.N.; Indelicato, P.; Shabaev, V.M.

    2003-01-01

    The present status of theoretical calculations of QED effects in highly charged ions is reviewed for several important cases: the Lamb shift in heavy H-like ions, the 2p 1/2 -2s transition energy in heavy Li-like ions, and the bound-electron g factor in H-like ions. Theoretical predictions are compared with experimental results. Special attention is paid to the discussion of uncertainties of theoretical predictions

  8. Progress in quantum electrodynamics theory of highly charged ions

    OpenAIRE

    Volotka, A. V.; Glazov, D. A.; Plunien, G.; Shabaev, V. M.

    2013-01-01

    Recent progress in quantum electrodynamics (QED) calculations of highly charged ions is reviewed. The theoretical predictions for the binding energies, the hyperfine splittings, and the g factors are presented and compared with available experimental data. Special attention is paid to tests of bound-state QED at strong field regime. Future prospects for tests of QED at the strongest electric and magnetic fields as well as for determination of the fine structure constant and the nuclear magnet...

  9. Electron capture by highly charged low-velocity ions

    International Nuclear Information System (INIS)

    Cocke, C.L.; Dubois, R.; Justiniano, E.; Gray, T.J.; Can, C.

    1982-01-01

    This paper describes the use of a fast heavy ion beam to produce, by bombardment of gaseous targets, highly-charged low-velocity recoil ions, and the use of these secondary ions in turn as projectiles in studies of electron capture and ionization in low-energy collision systems. The interest in collisions involving low-energy highly-charged projectiles comes both from the somewhat simplifying aspects of the physics which attend the long-range capture and from applications to fusion plasmas, astrophysics and more speculative technology such as the production of X-ray lasers. The ions of interest in such applications should have both electronic excitation and center-of-mass energies in the keV range and cannot be produced by simply stripping fast heavy ion beams. Several novel types of ion source have been developed to produce low-energy highly-charged ions, of which the secondary ion recoil source discussed in this paper is one. (Auth.)

  10. High throughput on-chip analysis of high-energy charged particle tracks using lensfree imaging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Wei; Shabbir, Faizan; Gong, Chao; Gulec, Cagatay; Pigeon, Jeremy; Shaw, Jessica; Greenbaum, Alon; Tochitsky, Sergei; Joshi, Chandrashekhar [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Ozcan, Aydogan, E-mail: ozcan@ucla.edu [Electrical Engineering Department, University of California, Los Angeles, California 90095 (United States); Bioengineering Department, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute (CNSI), University of California, Los Angeles, California 90095 (United States)

    2015-04-13

    We demonstrate a high-throughput charged particle analysis platform, which is based on lensfree on-chip microscopy for rapid ion track analysis using allyl diglycol carbonate, i.e., CR-39 plastic polymer as the sensing medium. By adopting a wide-area opto-electronic image sensor together with a source-shifting based pixel super-resolution technique, a large CR-39 sample volume (i.e., 4 cm × 4 cm × 0.1 cm) can be imaged in less than 1 min using a compact lensfree on-chip microscope, which detects partially coherent in-line holograms of the ion tracks recorded within the CR-39 detector. After the image capture, using highly parallelized reconstruction and ion track analysis algorithms running on graphics processing units, we reconstruct and analyze the entire volume of a CR-39 detector within ∼1.5 min. This significant reduction in the entire imaging and ion track analysis time not only increases our throughput but also allows us to perform time-resolved analysis of the etching process to monitor and optimize the growth of ion tracks during etching. This computational lensfree imaging platform can provide a much higher throughput and more cost-effective alternative to traditional lens-based scanning optical microscopes for ion track analysis using CR-39 and other passive high energy particle detectors.

  11. Status of Charge Exchange Cross Section Measurements for Highly Charged Ions on Atomic Hydrogen

    Science.gov (United States)

    Draganic, I. N.; Havener, C. C.; Schultz, D. R.; Seely, D. G.; Schultz, P. C.

    2011-05-01

    Total cross sections of charge exchange (CX) for C5+, N6+, and O7+ ions on ground state atomic hydrogen are measured in an extended collision energy range of 1 - 20,000 eV/u. Absolute CX measurements are performed using an improved merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source mounted on a high voltage platform. In order to improve the problematic H+ signal collection for these exoergic CX collisions at low relative energies, a new double focusing electrostatic analyzer was installed. Experimental CX data are in good agreement with all previous H-oven relative measurements at higher collision energies. We compare our results with the most recent molecular orbital close-coupling (MOCC) and atomic orbital close-coupling (AOCC) theoretical calculations. Work supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, and the Office of Basic Energy Sciences of the U.S. DoE.

  12. Optical Chirality in Nonlinear Optics: Application to High Harmonic Generation.

    Science.gov (United States)

    Neufeld, Ofer; Cohen, Oren

    2018-03-30

    Optical chirality (OC)-one of the fundamental quantities of electromagnetic fields-corresponds to the instantaneous chirality of light. It has been utilized for exploring chiral light-matter interactions in linear optics, but has not yet been applied to nonlinear processes. Motivated to explore the role of OC in the generation of helically polarized high-order harmonics and attosecond pulses, we first separate the OC of transversal and paraxial beams to polarization and orbital terms. We find that the polarization-associated OC of attosecond pulses corresponds approximately to that of the pump in the quasimonochromatic case, but not in the multichromatic pump cases. We associate this discrepancy with the fact that the polarization OC of multichromatic pumps vary rapidly in time along the optical cycle. Thus, we propose new quantities, noninstantaneous polarization-associated OC, and time-scale-weighted polarization-associated OC, and show that these quantities link the chirality of multichromatic pumps and their generated attosecond pulses. The presented extension to OC theory should be useful for exploring various nonlinear chiral light-matter interactions. For example, it stimulates us to propose a tricircular pump for generation of highly elliptical attosecond pulses with a tunable ellipticity.

  13. Optical Chirality in Nonlinear Optics: Application to High Harmonic Generation

    Science.gov (United States)

    Neufeld, Ofer; Cohen, Oren

    2018-03-01

    Optical chirality (OC)—one of the fundamental quantities of electromagnetic fields—corresponds to the instantaneous chirality of light. It has been utilized for exploring chiral light-matter interactions in linear optics, but has not yet been applied to nonlinear processes. Motivated to explore the role of OC in the generation of helically polarized high-order harmonics and attosecond pulses, we first separate the OC of transversal and paraxial beams to polarization and orbital terms. We find that the polarization-associated OC of attosecond pulses corresponds approximately to that of the pump in the quasimonochromatic case, but not in the multichromatic pump cases. We associate this discrepancy with the fact that the polarization OC of multichromatic pumps vary rapidly in time along the optical cycle. Thus, we propose new quantities, noninstantaneous polarization-associated OC, and time-scale-weighted polarization-associated OC, and show that these quantities link the chirality of multichromatic pumps and their generated attosecond pulses. The presented extension to OC theory should be useful for exploring various nonlinear chiral light-matter interactions. For example, it stimulates us to propose a tricircular pump for generation of highly elliptical attosecond pulses with a tunable ellipticity.

  14. Highly charged ion impact induced nanodefects in diamond

    Energy Technology Data Exchange (ETDEWEB)

    Makgato, T.N., E-mail: thuto.makgato@wits.ac.za [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Microscopy and Microanalysis Unit, University of the Witwatersrand, Johannesburg 2050 (South Africa); Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Centre of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa); Shrivastava, S. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Schenkel, T. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ritter, R.; Kowarik, G.; Aumayr, F. [Institute of Applied Physics, TU Wien-Vienna University of Technology, 1040 Vienna (Austria); Crespo Lopez-Urrutia, J.; Bernitt, S.; Beilmann, C.; Ginzel, R. [Max-Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg (Germany)

    2013-11-01

    We investigate the interaction of slow highly charged ion (SHCI) beams with insulating type Ib diamond (1 1 1) surfaces. Bismuth and Xenon SHCI beams produced using an Electron Beam Ion Trap (EBIT) and an Electron Cyclotron Resonance source (ECR) respectively, are accelerated onto type Ib diamond (1 1 1) surfaces with impact velocities up to ≈0.4 υ{sub Bohr}. SHCIs with charge states corresponding to potential energies between 4.5 keV and 110 keV are produced for this purpose. Atomic Force Microscopy analysis (AFM) of the diamond surfaces following SHCI impact reveals surface morphological modifications characterized as nanoscale craters (nano-craters). To interpret the results from Tapping Mode AFM analysis of the irradiated diamond surfaces we discuss the interplay between kinetic and potential energy in nano-crater formation using empirical data together with Stopping and Range of Ions in Matter (SRIM) Monte Carlo Simulations.

  15. Charge redistribution and properties of high-temperature superconductors

    International Nuclear Information System (INIS)

    Khomskii, D.I.; Kusmartsev, F.V.

    1992-01-01

    We show that in high-T c superconductors (HTSC) with two groups of electrons (e.g., holes in CuO 2 planes and in a ''reservoir'') there should exist a charge redistribution with the temperature: the hole concentration N h in ''active'' superconducting CuO 2 planes increases below T c . This effect may explain structural changes such as the shift of the apical oxygen atom, anomalous thermal expansion, the shift of nuclear quadrupole resonance lines, the change of the positron lifetime, and the modification of the ion channeling below T c . Some other possible consequences of the charge redistribution (the modification of the temperature dependence of a gap Δ and of the ratio 2Δ 0 /T c , the phenomena at a contact of HTSC with normal metals and semiconductors) are discussed

  16. Observation of the Dynamical Inversion of the Topological Charge of an Optical Vortex

    International Nuclear Information System (INIS)

    Molina-Terriza, Gabriel; Recolons, Jaume; Torres, Juan P.; Torner, Lluis; Wright, Ewan M.

    2001-01-01

    We report what is believed to be the first detailed experimental observation of the dynamic inversion of the topological charge of an optical vortex under free-space propagation. The vortex self-transformation occurs through continuous deformation of the noncanonical strength of the corresponding screw wave front dislocation, and is mediated by the occurrence of an extremely sharp turn in a Berry vortex trajectory, which observed at a Freund critical foliation appears as an edge-line dislocation orthogonal to the propagation direction, at a crucial point of the light evolution

  17. Increased-accuracy numerical modeling of electron-optical systems with space-charge

    International Nuclear Information System (INIS)

    Sveshnikov, V.

    2011-01-01

    This paper presents a method for improving the accuracy of space-charge computation for electron-optical systems. The method proposes to divide the computational region into two parts: a near-cathode region in which analytical solutions are used and a basic one in which numerical methods compute the field distribution and trace electron ray paths. A numerical method is used for calculating the potential along the interface, which involves solving a non-linear equation. Preliminary results illustrating the improvement of accuracy and the convergence of the method for a simple test example are presented.

  18. Optical method for mapping the transverse phase space of a charged particle beam

    International Nuclear Information System (INIS)

    Fiorito, R.B.; Shkvarunets, A.G.; O'Shea, P.G.

    2002-01-01

    We are developing an all optical method to map the transverse phase space map of a charged particle beam. Our technique employs OTR interferometry (OTRI) in combination with a scanning pinhole to make local orthogonal (x,y) divergence and trajectory angle measurements as function of position within the transverse profile of the beam. The localized data allows a reconstruction of the horizontal and vertical phase spaces of the beam. We have also demonstrated how single and multiple pinholes can in principle be used to make such measurements simultaneously

  19. Magnetic properties changes of MnAs thin films irradiated with highly charged ions

    OpenAIRE

    Trassinelli , Martino; Gafton , V.; Eddrief , Mahmoud; Etgens , Victor H.; Hidki , S.; Lacaze , Emmanuelle; Lamour , Emily; Luo , X.; Marangolo , Massimiliano; Merot , Jacques; Prigent , Christophe; Reuschl , Regina; Rozet , Jean-Pierre; Steydli , S.; Vernhet , Dominique

    2013-01-01

    International audience; We present the first investigation on the effect of highly charged ion bombardment on a manganese arsenide thin film. The MnAs films, 150~nm thick, are irradiated with 90 keV Ne$^{9+}$ ions with a dose varying from $1.6\\times10^{12}$ to $1.6\\times10^{15}$~ions/cm$^2$. The structural and magnetic properties of the film after irradiation are investigated using different techniques, namely, X-ray diffraction, magneto-optic Kerr effect and magnetic force microscope. Prelim...

  20. Fast charged-coupled device spectrometry using zoom-wavelength optics

    International Nuclear Information System (INIS)

    Carolan, P.G.; Conway, N.J.; Bunting, C.A.; Leahy, P.; OConnell, R.; Huxford, R.; Negus, C.R.; Wilcock, P.D.

    1997-01-01

    Fast charge-coupled device (CCD) detector arrays placed at the output of visible spectrometers are used for multichord Doppler shift analyses on the COMPASS-D and START tokamaks. Unequal magnification in the horizontal and vertical axes allows for optimal matching of throughput and spectral resolution at the CCD detector. This involves cylindrical lenses in an anamorphic mounting. Optical acuity is preserved over a very wide range of wavelengths (220 nm→700 nm) by separate repositioning of all the optical elements which is accomplished by the use of zoom mechanisms. This facilitates rapid changes of wavelength allowing edge and core observations depending on the location of the emitting impurity ions. Changes to the ion temperature and velocity are recorded using 20 chords simultaneously with typical accuracies of Δv i -1 and ΔT i /T i <10% with a time resolution of <1 ms. copyright 1997 American Institute of Physics

  1. Search for highly interacting fractionally charged particles at PEP

    International Nuclear Information System (INIS)

    Wlodzimierz, G.

    1982-01-01

    Fractionally charged, highly interacting particles produced in e + e - annihilation at 20 GeV c.m. energy have been search for. The experiment was performed at the positron electron storage ring (PEP) at the Stanford Linear Accelerator Center (SLAC). The search used in the innermost part of the two-arm Free Quark Search (FQS) detector. This part was called the Thin Front End (TFE) and it covered 1/3 of the full solid angle. Each of its arms consisted of five multiwire proportional chambers (MWPC's), used for tracking and dE/dx measurement, and three hodoscopes of 0.16 cm thick Pilot F scintillator. The total thickness of the five MWPC's and the beam pipe was 0.007 hadronic collision lengths (lambda/sub c/). No candidates for fractionally charged particles were found. Upper limits on R/sub q anti q/ = sigma(e + e - →q anti q)/sigma(e + e - →μμ) are between: (1) 0.7% to 7% for quark interaction lengths (lambda/sub q/) equal to lambda/sub c/ and between 3% and 33% for lambda/sub q/ = 100lambda/sub c/ for Q = 1/3e quark charge and for quark masses up to 13 GeV/c 2 ; (2) 2% to 38% for lambda/sub q/ - lambda/sub c/ and from 7% to 160% for lambda/sub q/ = 100lambda/sub c/ for Q = 2/3e quark charge and for masses up to 8 GeV/c 2 . In the inclusive production channel the upper limits on R/sub q/ = sigma(e + e - →qqX)/sigma(e + e - →μμ) are for charge 1/3e only. R/sub q/ varies from 2% to 11% for lambda/sub q/ = lambda/sub c/ and from 3% to 16% for lambda/sub q/ = 100lambda/sub c/ and for quark masses up to 6.5 GeV/c 2 . These are the first limits on the production of fractionally charged particles with lambda/sub q/ = 100lambda/sub c/

  2. Temperature Dependence of Charge Localization in High-Mobility, Solution-Crystallized Small Molecule Semiconductors Studied by Charge Modulation Spectroscopy

    DEFF Research Database (Denmark)

    Meneau, Aurélie Y. B.; Olivier, Yoann; Backlund, Tomas

    2016-01-01

    In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld-effect tran......In solution-processable small molecule semiconductors, the extent of charge carrier wavefunction localization induced by dynamic disorder can be probed spectroscopically as a function of temperature using charge modulation spectroscopy (CMS). Here, it is shown based on combined fi eld......-effect transistor and CMS measurements as a function of temperature that in certain molecular semiconductors, such as solution-processible pentacene, charge carriers become trapped at low temperatures in environments in which the charges become highly localized on individual molecules, while in some other molecules...

  3. High Optical Access Trap 2.0.

    Energy Technology Data Exchange (ETDEWEB)

    Maunz, Peter Lukas Wilhelm [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-26

    The High Optical Access (HOA) trap was designed in collaboration with the Modular Universal Scalable Ion-trap Quantum Computer (MUSIQC) team, funded along with Sandia National Laboratories through IARPA's Multi Qubit Coherent Operations (MQCO) program. The design of version 1 of the HOA trap was completed in September 2012 and initial devices were completed and packaged in February 2013. The second version of the High Optical Access Trap (HOA-2) was completed in September 2014 and is available at IARPA's disposal.

  4. Anisotropy in highly charged ion induced molecule fragmentation

    International Nuclear Information System (INIS)

    Juhasz, Z.; Sulik, B.; Fremont, F.; Chesnel, J.Y.; Hajaji, A.

    2006-01-01

    Complete text of publication follows. Studying fragmentation processes of biologically relevant molecules due to highly charged ion impact is important to understand radiation damage in biological tissues. Energy spectra of the charged molecule fragments may reveal the different fragmentation patterns meanwhile the angular distributions of the fragments characterize the dependence of fragmentation probability on the initial orientation of the molecule. The research to explore the angular distribution of the molecule fragments has only recently been started[1]. In 2006 we performed measurements at ARIBE facility at GANIL, Caen (France), in order to investigate orientation effects in molecule fragmentation. Fragmentation of H 2 O, C 6 H 6 and CH 4 , which represent different level of symmetry, have been studied by 60 keV N 6+ ion impact. Energy spectra of the charged fragments at different observation angles have been taken. As our example spectra show the different protonic peaks can be attributed to different fragmentation processes. Significant anisotropy can be seen in the different processes. The strongest evidence for the anisotropy can be seen in the spectra of C 6 H 6 , where the spectra appear isotropic in almost the whole observed energy range except one peak, which has a strong angular dependence and is maximal around 90 deg. (author)

  5. Optical Fiber for High-Power Optical Communication

    Directory of Open Access Journals (Sweden)

    Kenji Kurokawa

    2012-09-01

    Full Text Available We examined optical fibers suitable for avoiding such problems as the fiber fuse phenomenon and failures at bends with a high power input. We found that the threshold power for fiber fuse propagation in photonic crystal fiber (PCF and hole-assisted fiber (HAF can exceed 18 W, which is more than 10 times that in conventional single-mode fiber (SMF. We considered this high threshold power in PCF and HAF to be caused by a jet of high temperature fluid penetrating the air holes. We showed examples of two kinds of failures at bends in conventional SMF when the input power was 9 W. We also observed the generation of a fiber fuse under a condition that caused a bend-loss induced failure. We showed that one solution for the failures at bends is to use optical fibers with a low bending loss such as PCF and HAF. Therefore, we consider PCF and HAF to be attractive solutions to the problems of the fiber fuse phenomenon and failures at bends with a high power input.

  6. Small electrostatic storage rings; also for highly charged ions?

    International Nuclear Information System (INIS)

    Moeller, S.P.; Pedersen, U.V.

    2001-01-01

    Two years ago, a small electrostatic storage ring ELISA (electrostatic ion storage ring, Aarhus) was put into operation. The design of this small 7 m circumference ring was based on electrostatic deflection plates and quadrupoles. This is in contrast to the larger ion storage rings, which are based on magnetic focusing and deflection. The result is a small, relatively inexpensive, storage ring being able to store ions of any mass and any charge at low energy ( -11 mbar resulting in storage times of several tens of seconds for singly charged ions. The maximum number of singly charged ions that can be stored is a few 10 7 . Several experiments have already been performed in ELISA. These include lifetime studies of metastable ions and studies of fullerenes and metal-cluster ions. Lasers are also used for excitation of the circulating ions. Heating/cooling of the ring is possible. Cooling of the ring leads to significantly lower pressures, and correspondingly longer lifetimes. A change of the temperature of the vacuum chambers surrounding the ion beam also leads to a change of the spectrum of the black-body radiation, which has a significant influence on weakly bound negative ions. At the time of writing, at least two other electrostatic storage rings are being built, and more are planned. In the following, the electrostatic storage ring ELISA will be described, and results from some of the initial experiments demonstrating the performance will be shown. The relative merits of such a ring, as opposed to the larger magnetic rings and the smaller ion traps will be discussed. The potential for highly charged ions will be briefly mentioned. (orig.)

  7. Structural Arrangement of Water Molecules around Highly Charged Nanoparticles: Molecular Dynamics Simulation

    International Nuclear Information System (INIS)

    Kim, Eunae; Yeom, Min Sun

    2014-01-01

    Molecular dynamics simulations were performed to understand the structural arrangement of water molecules around highly charged nanoparticles under aqueous conditions. The effect of two highly charged nanoparticles on the solvation charge asymmetry has been examined. We calculated the radial distribution functions of the components of water molecules around nanoparticles which have four charge types at two different salt concentrations. Even though the distributions of water molecules surrounding a sodium ion and a chloride ion are hardly affected by the charges of nanoparticles and the salt concentrations, those around highly charged nanoparticles are strongly influenced by the charges of nanoparticles, but hardly by the charges of nanoparticles and salt concentrations. We find that the distributions of hydrogen atoms in water molecules around one highly charged nanoparticle are dependent on the magnitude of the nanoparticle charge

  8. Progress in high index contrast integrated optics

    NARCIS (Netherlands)

    Baets, R.G.F.; Bienstman, P.; Bogaerts, W.; Brouckaert, J.; De Backere, P.; Dumon, P.; Roelkens, G.; Scheerlinck, S.; Smit, M.K.; Taillaert, D.; Van Campenhout, J.; Van Laere, F.; Thourhout, Van D.

    2007-01-01

    A large fraction of the recent innovation in integrated optics is enabled by the use of high index contrast structures and devices. The strong confinement achievable in such devices allows for dramatic performance benefits and downscaling. In this paper the progress in this field is reviewed.

  9. Strong-field relativistic processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Postavaru, Octavian

    2010-12-08

    In this thesis we investigate strong-field relativistic processes in highly charged ions. In the first part, we study resonance fluorescence of laser-driven highly charged ions in the relativistic regime by solving the time-dependent master equation in a multi-level model. Our ab initio approach based on the Dirac equation allows for investigating highly relativistic ions, and, consequently, provides a sensitive means to test correlated relativistic dynamics, bound-state quantum electrodynamic phenomena and nuclear effects by applying coherent light with x-ray frequencies. Atomic dipole or multipole moments may be determined to unprecedented accuracy by measuring the interference-narrowed fluorescence spectrum. Furthermore, we investigate the level structure of heavy hydrogenlike ions in laser beams. Interaction with the light field leads to dynamic shifts of the electronic energy levels, which is relevant for spectroscopic experiments. We apply a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the dipole approximation and takes into account non-dipole effects of retardation and interaction with the magnetic field components of the laser beam. We predicted cross sections for the inter-shell trielectronic recombination (TR) and quadruelectronic recombination processes which have been experimentally confirmed in electron beam ion trap measurements, mainly for C-like ions, of Ar, Fe and Kr. For Kr{sup 30}+, inter-shell TR contributions of nearly 6% to the total resonant photorecombination rate were found. (orig.)

  10. Irradiation of graphene field effect transistors with highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, P.; Kozubek, R.; Madauß, L.; Sonntag, J.; Lorke, A.; Schleberger, M., E-mail: marika.schleberger@uni-due.de

    2016-09-01

    In this work, graphene field-effect transistors are used to detect defects due to irradiation with slow, highly charged ions. In order to avoid contamination effects, a dedicated ultra-high vacuum set up has been designed and installed for the in situ cleaning and electrical characterization of graphene field-effect transistors during irradiation. To investigate the electrical and structural modifications of irradiated graphene field-effect transistors, their transfer characteristics as well as the corresponding Raman spectra are analyzed as a function of ion fluence for two different charge states. The irradiation experiments show a decreasing mobility with increasing fluences. The mobility reduction scales with the potential energy of the ions. In comparison to Raman spectroscopy, the transport properties of graphene show an extremely high sensitivity with respect to ion irradiation: a significant drop of the mobility is observed already at fluences below 15 ions/μm{sup 2}, which is more than one order of magnitude lower than what is required for Raman spectroscopy.

  11. Atomic physics with highly charged ions. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Richard, P.

    1994-08-01

    The study of inelastic collision phenomena with highly charged projectile ions and the interpretation of spectral features resulting from these collisions remain as the major focal points in the atomic physics research at the J.R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas. The title of the research project, ``Atomic Physics with Highly Charged Ions,`` speaks to these points. The experimental work in the past few years has divided into collisions at high velocity using the primary beams from the tandem and LINAC accelerators and collisions at low velocity using the CRYEBIS facility. Theoretical calculations have been performed to accurately describe inelastic scattering processes of the one-electron and many-electron type, and to accurately predict atomic transition energies and intensities for x rays and Auger electrons. Brief research summaries are given for the following: (1) electron production in ion-atom collisions; (2) role of electron-electron interactions in two-electron processes; (3) multi-electron processes; (4) collisions with excited, aligned, Rydberg targets; (5) ion-ion collisions; (6) ion-molecule collisions; (7) ion-atom collision theory; and (8) ion-surface interactions.

  12. Optical high-performance computing: introduction to the JOSA A and Applied Optics feature.

    Science.gov (United States)

    Caulfield, H John; Dolev, Shlomi; Green, William M J

    2009-08-01

    The feature issues in both Applied Optics and the Journal of the Optical Society of America A focus on topics of immediate relevance to the community working in the area of optical high-performance computing.

  13. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

    International Nuclear Information System (INIS)

    2005-01-01

    Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

  14. LISA technologies in new light: exploring alternatives for charge management and optical bench construction

    Science.gov (United States)

    Ciani, Giacomo; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Conklin, John W.; Mueller, Guido

    2015-08-01

    A LISA-like gravitational wave observatory is the choice candidate for ESA's L3 large mission scheduled to launch in 2034. The LISA Test Package (LTP) mission will launch later this year and test many critical technologies needed for such an observatory, among which are picometer interferometry in space and UV charge management of the Test Mass (TM). The design of these subsystems has been frozen many years ago during the final formulation of the LTP mission; since then, the LISA mission concept has evolved and new technologies have become available, making it possible to re-think the way these subsystem are implemented. With the final formulation of the L3 mission still years in the future and the LTP results expected in about one year, now is an ideal time look for areas of possible improvement and explore alternative implementations that can enhance performance, reduce costs or mitigate risks.Recently developed UV LED are lighter, cheaper and more powerful than traditional mercury lamps; in addition, their fast response time can be used to implement AC discharge techniques that can save even more space and power, and provide a more precise control of the charge.The most recent iteration of the mission baseline design allows for eliminating some of the optical components initially deemed essential; paired with the use of polarization multiplexing, this permits a redesign of the optical bench that simplifies the layout and enables a modular approach to machining and assembly, thus reducing the risks and costs associated with the current monolithic design without compromising the picometer stability of the optical path.Leveraging on extensive previous experience with LISA interferometry and the availability of a torsion pendulum-based LISA test-bed, the University of Florida LISA group is working at developing, demonstrating and optimizing both these technologies. I will describe the most recent advancements and results.

  15. Method and apparatus of highly linear optical modulation

    Science.gov (United States)

    DeRose, Christopher; Watts, Michael R.

    2016-05-03

    In a new optical intensity modulator, a nonlinear change in refractive index is used to balance the nonlinearities in the optical transfer function in a way that leads to highly linear optical intensity modulation.

  16. Fiber optics in high dose radiation fields

    International Nuclear Information System (INIS)

    Partin, J.K.

    1985-01-01

    A review of the behavior of state-of-the-art optical fiber waveguides in high dose (greater than or equal to 10 5 rad), steady state radiation fields is presented. The influence on radiation-induced transmission loss due to experimental parameters such as dose rate, total dose, irradiation history, temperature, wavelength, and light intensity, for future work in high dose environments are given

  17. Electromagnetic Charge Radius of the Pion at High Precision

    Science.gov (United States)

    Ananthanarayan, B.; Caprini, Irinel; Das, Diganta

    2017-09-01

    We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.

  18. Performance of the PHIN High Charge Photo Injector

    CERN Document Server

    Petrarca, M; Doebert, S; Dabrowski, A; Divall, M; Fedoseev, V; Lebas, N; Lefevre, T; Losito, R; Egger, D; Mete, O

    2010-01-01

    The high charge PHIN photo injector is studied at CERN as an electron source for the CLIC Test Facility (CTF3) drive beam as an alternative to the present thermionic gun. The objective of PHIN is to demonstrate the feasibility of a laser-based electron source for CLIC. The photo injector operates with a 2.5 cell, 3 GHz RF gun using a Cs2Te photocathode illuminated by UV laser pulses generated by amplifying and frequency quadrupling the signal from a Nd:YLF oscillator running at 1.5GHz. The challenge is to generate a beam structure of 1908 micro bunches with 2.33nC per micro bunch at 1.5GHz leading to a high integrated train charge of 4446nC and nominal beam energy of 5.5MeV with current stability below 1%. In this paper we report and discuss the time resolved transverse and longitudinal beam parameters measurements. The performance of the photo cathodes made at CERN with a peak quantum efficiency of 18 % is shown as well. Laser pointing and amplitude stability results are discussed taking into account correla...

  19. Optical signal processing for enabling high-speed, highly spectrally efficient and high capacity optical systems

    Science.gov (United States)

    Fazal, Muhammad Irfan

    The unabated demand for more capacity due to the ever-increasing internet traffic dictates that the boundaries of the state of the art maybe pushed to send more data through the network. Traditionally, this need has been satisfied by multiple wavelengths (wavelength division multiplexing), higher order modulation formats and coherent communication (either individually or combined together). WDM has the ability to reduce cost by using multiple channels within the same physical fiber, and with EDFA amplifiers, the need for O-E-O regenerators is eliminated. Moreover the availability of multiple colors allows for wavelength-based routing and network planning. Higher order modulation formats increases the capacity of the link by their ability to encode data in both the phase and amplitude of light, thereby increasing the bits/sec/Hz as compared to simple on-off keyed format. Coherent communications has also emerged as a primary means of transmitting and receiving optical data due to its support of formats that utilize both phase and amplitude to further increase the spectral efficiency of the optical channel, including quadrature amplitude modulation (QAM) and quadrature phase shift keying (QPSK). Polarization multiplexing of channels can double capacity by allowing two channels to share the same wavelength by propagating on orthogonal polarization axis and is easily supported in coherent systems where the polarization tracking can be performed in the digital domain. Furthermore, the forthcoming IEEE 100 Gbit/s Ethernet Standard, 802.3ba, provides greater bandwidth, higher data rates, and supports a mixture of modulation formats. In particular, Pol-MUX QPSK is increasingly becoming the industry's format of choice as the high spectral efficiency allows for 100 Gbit/s transmission while still occupying the current 50 GHz/channel allocation of current 10 Gbit/s OOK fiber systems. In this manner, 100 Gbit/s transfer speeds using current fiber links, amplifiers, and filters

  20. Performance improvement of charge trap flash memory by using a composition-modulated high-k trapping layer

    International Nuclear Information System (INIS)

    Tang Zhen-Jie; Li Rong; Yin Jiang

    2013-01-01

    A composition-modulated (HfO 2 ) x (Al 2 O3) 1−x charge trapping layer is proposed for charge trap flash memory by controlling the Al atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated (HfO 2 ) x (Al 2 O 3 ) 1−x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  1. Optical properties of high-Tc superconductors

    International Nuclear Information System (INIS)

    Aspnes, D.E.; Kelly, M.K.

    1989-01-01

    The authors summarize the present status of optical spectroscopy of high-T c superconductors. The optical properties of these materials resemble those of the more common transition metal oxides except for being highly anisotropic in the infrared (IR). This large IR anisotrophy and a need to rely solely on reflectance techniques has hindered progress in obtaining accurate IR data and interpreting these data in terms of microscopic mechanisms. However, experimental consistency is now being approached with single-crystal samples, although interpretations of these data remain controversial and an unequivocal demonstration of a superconducting gap structure has not yet been achieved. The mid IR exhibits an absorption band whose systematics are neither well established nor understood. The situation in the visible-near-ultraviolet (V-NUV) is better, partly because of greatly reduced optical anisotropy and the availability of alternative measurement techniques that are not strongly affected by the lower optical quality of sintered material. As polycrystalline, sintered samples can be prepared relatively easily over wide ranges of composition, doping, and chemical substitution, most work on studying the chemical systematics of these materials has been done in this spectral range and some of the structure that appears here has been positively identified

  2. Space-charge effects in high-energy photoemission

    Energy Technology Data Exchange (ETDEWEB)

    Verna, Adriano, E-mail: adriano.verna@uniroma3.it [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Greco, Giorgia [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Lollobrigida, Valerio [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Scuola Dottorale in Matematica e Fisica, Università Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); Offi, Francesco; Stefani, Giovanni [Dipartimento di Scienze, Università degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy); CNISM Unità di Roma Tre, Via della Vasca Navale 84, I-00146 Roma (Italy)

    2016-05-15

    Highlights: • N-body simulations of interacting photoelectrons in hard X-ray experiments. • Secondary electrons have a pivotal role in determining the energy broadening. • Space charge has negligible effects on the photoelectron momentum distribution. • A simple model provides the characteristic time for energy-broadening mechanism. • The feasibility of time-resolved high-energy experiments with FELs is discussed. - Abstract: Pump-and-probe photoelectron spectroscopy (PES) with femtosecond pulsed sources opens new perspectives in the investigation of the ultrafast dynamics of physical and chemical processes at the surfaces and interfaces of solids. Nevertheless, for very intense photon pulses a large number of photoelectrons are simultaneously emitted and their mutual Coulomb repulsion is sufficiently strong to significantly modify their trajectory and kinetic energy. This phenomenon, referred as space-charge effect, determines a broadening and shift in energy for the typical PES structures and a dramatic loss of energy resolution. In this article we examine the effects of space charge in PES with a particular focus on time-resolved hard X-ray (∼10 keV) experiments. The trajectory of the electrons photoemitted from pure Cu in a hard X-ray PES experiment has been reproduced through N-body simulations and the broadening of the photoemission core-level peaks has been monitored as a function of various parameters (photons per pulse, linear dimension of the photon spot, photon energy). The energy broadening results directly proportional to the number N of electrons emitted per pulse (mainly represented by secondary electrons) and inversely proportional to the linear dimension a of the photon spot on the sample surface, in agreement with the literature data about ultraviolet and soft X-ray experiments. The evolution in time of the energy broadening during the flight of the photoelectrons is also studied. Despite its detrimental consequences on the energy

  3. A modified space charge routine for high intensity bunched beams

    International Nuclear Information System (INIS)

    Lapostolle, P.; Garnett, R.W.; Wangler, T.P.

    1996-01-01

    In 1991 a space charge calculation for bunched beam with a three-dimensional ellipsoid was proposed, replacing the usual SCHEFF routines. It removes the cylindrical symmetry required in SCHEFF and avoids the point to point interaction computation, whose number of simulation points is limited. This routine has now been improved with the introduction of two or three ellipsoids giving a good representation of the complex non-symmetrical form of the bunch (unlike the 3-d ellipsoidal assumption). The ellipsoidal density distributions are computed with a new method, avoiding the difficulty encountered near the centre (the axis in 2-d problems) by the previous method. It also provides a check of the ellipsoidal symmetry for each part of the distribution. Finally, the Fourier analysis reported in 1991 has been replaced by a very convenient Hermite expansion, which gives a simple but accurate representation of practical distributions. Comparisons with other space charge routines have been made, particularly with the ones applying other techniques such as SCHEFF. Introduced in the versatile beam dynamics code DYNAC, it should provide a good tool for the study of the various parameters responsible for the halo formation in high intensity linacs. (orig.)

  4. High resolution optical spectroscopy of air-induced electrical instabilities in n-type polymer semiconductors.

    Science.gov (United States)

    Di Pietro, Riccardo; Sirringhaus, Henning

    2012-07-03

    We use high-resolution charge-accumulation optical spectroscopy to measure charge accumulation in the channel of an n-type organic field-effect transistor. We monitor the degradation of device performance in air, correlate the onset voltage shift with the reduction of charge accumulated in the polymer semiconductor, and explain the results in view of the redox reaction between the polymer, water and oxygen in the accumulation layer. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Towards green high capacity optical networks

    Science.gov (United States)

    Glesk, I.; Mohd Warip, M. N.; Idris, S. K.; Osadola, T. B.; Andonovic, I.

    2011-09-01

    The demand for fast, secure, energy efficient high capacity networks is growing. It is fuelled by transmission bandwidth needs which will support among other things the rapid penetration of multimedia applications empowering smart consumer electronics and E-businesses. All the above trigger unparallel needs for networking solutions which must offer not only high-speed low-cost "on demand" mobile connectivity but should be ecologically friendly and have low carbon footprint. The first answer to address the bandwidth needs was deployment of fibre optic technologies into transport networks. After this it became quickly obvious that the inferior electronic bandwidth (if compared to optical fiber) will further keep its upper hand on maximum implementable serial data rates. A new solution was found by introducing parallelism into data transport in the form of Wavelength Division Multiplexing (WDM) which has helped dramatically to improve aggregate throughput of optical networks. However with these advancements a new bottleneck has emerged at fibre endpoints where data routers must process the incoming and outgoing traffic. Here, even with the massive and power hungry electronic parallelism routers today (still relying upon bandwidth limiting electronics) do not offer needed processing speeds networks demands. In this paper we will discuss some novel unconventional approaches to address network scalability leading to energy savings via advance optical signal processing. We will also investigate energy savings based on advanced network management through nodes hibernation proposed for Optical IP networks. The hibernation reduces the network overall power consumption by forming virtual network reconfigurations through selective nodes groupings and by links segmentations and partitionings.

  6. Experimental investigation on the use of highly charged nanoparticles to improve the stability of weakly charged colloidal system.

    Science.gov (United States)

    Zubir, Mohd Nashrul Mohd; Badarudin, A; Kazi, S N; Misran, Misni; Amiri, Ahmad; Sadri, Rad; Khalid, Solangi

    2015-09-15

    The present work highlighted on the implementation of a unique concept for stabilizing colloids at their incipiently low charge potential. A highly charged nanoparticle was introduced within a coagulated prone colloidal system, serving as stabilizer to resist otherwise rapid flocculation and sedimentation process. A low size asymmetry of nanoparticle/colloid serves as the new topic of investigation in addition to the well-established large size ratio nanoparticle/microparticle study. Highly charged Al2O3 nanoparticles were used within the present research context to stabilize TiO2 and Fe3O4 based colloids via the formation of composite structures. It was believed, based on the experimental evidence, that Al2O3 nanoparticle interact with the weakly charged TiO2 and Fe3O4 colloids within the binary system via absorption and/or haloing modes to increase the overall charge potential of the respective colloids, thus preventing further surface contact via van der Waal's attraction. Series of experimental results strongly suggest the presence of weakly charged colloids in the studied bimodal system where, in the absence of highly charged nanoparticle, experience rapid instability. Absorbance measurement indicated that the colloidal stability drops in accordance to the highly charged nanoparticle sedimentation rate, suggesting the dominant influence of nanoparticles to attain a well-dispersed binary system. Further, it was found that the level of colloidal stability was enhanced with increasing nanoparticle fraction within the mixture. Rheological observation revealed that each hybrid complexes demonstrated behavior reminiscence to water with negligible increase in viscosity which serves as highly favorable condition particularly in thermal transport applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Twisted intra-molecular charge transfer investigations of semiorganic triglycine phosphate single crystal for non linear optical applications

    Science.gov (United States)

    Meera, M. R.; Joselin Beaula, T.; Rayar, S. L.; Bena Jothy, V.

    2017-09-01

    NLO materials are gaining importance in technologies such as optical communication, optical computing and dynamic image processing. Many NLO crystals grown by mixing amino acids with various organic and inorganic acids have been reported in the literature. Hence, glycine mixed semi-organic material will be of special interest as a fundamental building block to develop many complex crystals with improved NLO properties. A semi organic Single crystal of Triglycine Phosphate (TGP) which was grown and spectral analysis have been using FTIR and Raman spectral analysis. Natural Bond Orbital Analysis and the atomic natural charges are also predicted. HOMO LUMO energy gap value suggests the possibility of charge transfer within the molecule.

  8. High power VCSELs for miniature optical sensors

    Science.gov (United States)

    Geske, Jon; Wang, Chad; MacDougal, Michael; Stahl, Ron; Follman, David; Garrett, Henry; Meyrath, Todd; Snyder, Don; Golden, Eric; Wagener, Jeff; Foley, Jason

    2010-02-01

    Recent advances in Vertical-cavity Surface-emitting Laser (VCSEL) efficiency and packaging have opened up alternative applications for VCSELs that leverage their inherent advantages over light emitting diodes and edge-emitting lasers (EELs), such as low-divergence symmetric emission, wavelength stability, and inherent 2-D array fabrication. Improvements in reproducible highly efficient VCSELs have allowed VCSELs to be considered for high power and high brightness applications. In this talk, Aerius will discuss recent advances with Aerius' VCSELs and application of these VCSELs to miniature optical sensors such as rangefinders and illuminators.

  9. Understanding optically stimulated charge movement in quartz and feldspar using time-resolved measurements

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina

    . Although, results are only presented for some quartz and feldspar samples, they were found to be very similar within the each group during the course of this work.Thermoluminescence (TL) and optically stimulated luminescence (OSL) from quartz and feldspar are widely used in accident dosimetry...... stimulation energy. The thesis first delves into three main methodological developments, namely (i) research and development of the equipment for TR-OSL measurements, (ii) finding the best method for multiple-exponential analysis of a TR-OSL curve, and (iii) optimisation of the pulsing configuration...... of the equipment for TR-OSL measurements, (ii) finding the best method for multiple-exponential analysis of a TR-OSL curve, and (iii) optimisation of the pulsing configuration for the best separation of quartz OSL from a mixed quarts-feldspar sample. It then proceeds to study the different charge transport...

  10. High-Resolution Integrated Optical System

    Science.gov (United States)

    Prakapenka, V. B.; Goncharov, A. F.; Holtgrewe, N.; Greenberg, E.

    2017-12-01

    Raman and optical spectroscopy in-situ at extreme high pressure and temperature conditions relevant to the planets' deep interior is a versatile tool for characterization of wide range of properties of minerals essential for understanding the structure, composition, and evolution of terrestrial and giant planets. Optical methods, greatly complementing X-ray diffraction and spectroscopy techniques, become crucial when dealing with light elements. Study of vibrational and optical properties of minerals and volatiles, was a topic of many research efforts in past decades. A great deal of information on the materials properties under extreme pressure and temperature has been acquired including that related to structural phase changes, electronic transitions, and chemical transformations. These provide an important insight into physical and chemical states of planetary interiors (e.g. nature of deep reservoirs) and their dynamics including heat and mass transport (e.g. deep carbon cycle). Optical and vibrational spectroscopy can be also very instrumental for elucidating the nature of the materials molten states such as those related to the Earth's volatiles (CO2, CH4, H2O), aqueous fluids and silicate melts, planetary ices (H2O, CH4, NH3), noble gases, and H2. The optical spectroscopy study performed concomitantly with X-ray diffraction and spectroscopy measurements at the GSECARS beamlines on the same sample and at the same P-T conditions would greatly enhance the quality of this research and, moreover, will provide unique new information on chemical state of matter. The advanced high-resolution user-friendly integrated optical system is currently under construction and expected to be completed by 2018. In our conceptual design we have implemented Raman spectroscopy with five excitation wavelengths (266, 473, 532, 660, 946 nm), confocal imaging, double sided IR laser heating combined with high temperature Raman (including coherent anti-Stokes Raman scattering) and

  11. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    International Nuclear Information System (INIS)

    Panitzsch, Lauri

    2013-01-01

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet (∼45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to other

  12. Spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Panitzsch, Lauri

    2013-02-08

    The experimental determination of the spatial distribution of charged particles along the ion-optical axis in electron cyclotron resonance ion sources (ECRIS) defines the focus of this thesis. The spatial distributions of different ion species were obtained in the object plane of the bending magnet ({approx}45 cm downstream from the plasma electrode) and in the plane of the plasma electrode itself, both in high spatial resolution. The results show that each of the different ion species forms a bloated, triangular structure in the aperture of the plasma electrode. The geometry and the orientation of these structures are defined by the superposition of the radial and axial magnetic fields. The radial extent of each structure is defined by the charge of the ion. Higher charge states occupy smaller, more concentrated structures. The total current density increases towards the center of the plasma electrode. The circular and star-like structures that can be observed in the beam profiles of strongly focused, extracted ion beams are each dominated by ions of a single charge state. In addition, the spatially resolved current density distribution of charged particles in the plasma chamber that impinge on the plasma electrode was determined, differentiating between ions and electrons. The experimental results of this work show that the electrons of the plasma are strongly connected to the magnetic field lines in the source and thus spatially well confined in a triangular-like structure. The intensity of the electrons increases towards the center of the plasma electrode and the plasma chamber, as well. These electrons are surrounded by a spatially far less confined and less intense ion population. All the findings mentioned above were already predicted in parts by simulations of different groups. However, the results presented within this thesis represent the first (and by now only) direct experimental verification of those predictions and are qualitatively transferable to

  13. Highly charged ion based time-of-flight emission microscope

    International Nuclear Information System (INIS)

    Hamza, Alex V.; Barnes, Alan V.; Magee, Ed; Newman, Mike; Schenkel, Thomas; McDonald, Joseph W.; Schneider, Dieter H.

    2000-01-01

    An emission microscope using highly charged ions as the excitation source has been designed, constructed, and operated. A novel ''acorn'' objective lens has been used to simultaneously image electron and secondary ion emission. A resistive anode-position sensitive detector is used to determine the x-y position and time of arrival of the secondary events at the microscope image plane. Contrast in the image can be based on the intensity of the electron emission and/or the presence of particular secondary ions. Spatial resolution of better than 1 μm and mass resolution m/Δm of better than 400 were demonstrated. Background rejection from uncorrelated events of greater than an order of magnitude is also achieved. (c) 2000 American Institute of Physics

  14. Nonlinear energy loss of highly charged heavy ions

    International Nuclear Information System (INIS)

    Zwicknagel, G.Guenter.

    2000-01-01

    For slow, highly charged heavy ions strong coupling effects in the energy transfer from the projectile-ion to an electron target plasma become important. A theoretical description of this nonlinear ion stopping has to go beyond the standard approaches like the dielectric linear response or the binary collision model which are strictly valid only at weak ion-target coupling. Here we outline an improved treatment which is based on a suitable combination of binary collision and linear response contributions. As has been verified for isotropic, nonmagnetized electron plasmas by comparison with simulations, this approach well reproduces the essential features of nonlinear stopping up to moderate coupling strength. Its extension to anisotropic, magnetized electron plasmas basically involves the fully numerical determination of the momentum and energy transfer in binary ion-electron collisions in the presence of a magnetic field. First results of such calculations are presented and discussed

  15. Highly charged ions at rest: The HITRAP project at GSI

    International Nuclear Information System (INIS)

    Herfurth, F.; Beier, T.; Dahl, L.; Eliseev, S.; Heinz, S.; Kester, O.; Kluge, H.-J.; Kozhuharov, C.; Maero, G.; Quint, W.

    2005-01-01

    A decelerator will be installed at GSI in order to provide and study bare heavy nuclei or heavy nuclei with only few electrons at very low energies or even at rest. Highly-charged ions will be produced by stripping at relativistic energies. After electron cooling and deceleration in the Experimental Storage Ring the ions are ejected out of the storage ring at 4 MeV/u and further decelerated in a combination of an IH and RFQ structure. Finally, they are injected into a Penning trap where the ions are cooled to 4 K. From here, the ions can be transferred in a quasi dc or in a pulsed mode to different experimental setups. This article describes the technical concepts of this project as well as planned key experiments

  16. High cumulants of conserved charges and their statistical uncertainties

    Science.gov (United States)

    Li-Zhu, Chen; Ye-Yin, Zhao; Xue, Pan; Zhi-Ming, Li; Yuan-Fang, Wu

    2017-10-01

    We study the influence of measured high cumulants of conserved charges on their associated statistical uncertainties in relativistic heavy-ion collisions. With a given number of events, the measured cumulants randomly fluctuate with an approximately normal distribution, while the estimated statistical uncertainties are found to be correlated with corresponding values of the obtained cumulants. Generally, with a given number of events, the larger the cumulants we measure, the larger the statistical uncertainties that are estimated. The error-weighted averaged cumulants are dependent on statistics. Despite this effect, however, it is found that the three sigma rule of thumb is still applicable when the statistics are above one million. Supported by NSFC (11405088, 11521064, 11647093), Major State Basic Research Development Program of China (2014CB845402) and Ministry of Science and Technology (MoST) (2016YFE0104800)

  17. X-ray radiography with highly charged ions

    Science.gov (United States)

    Marrs, Roscoe E.

    2000-01-01

    An extremely small (1-250 micron FWHM) beam of slow highly charged ions deexciting on an x-ray production target generates x-ray monochromatic radiation that is passed through a specimen and detected for imaging. The resolution of the x-ray radiograms is improved and such detection is achieved with relatively low dosages of radiation passing through the specimen. An apparatus containing an electron beam ion trap (and modifications thereof) equipped with a focusing column serves as a source of ions that generate radiation projected onto an image detector. Electronic and other detectors are able to detect an increased amount of radiation per pixel than achieved by previous methods and apparati.

  18. High-resolution CT of lesions of the optic nerve

    International Nuclear Information System (INIS)

    Peyster, R.G.; Hoover, E.D.; Hershey, B.L.; Haskin, M.E.

    1983-01-01

    The optic nerves are well demonstrated by high-resolution computed tomography. Involvement of the optic nerve by optic gliomas and optic nerve sheath meningiomas is well known. However, nonneoplastic processes such as increased intracranial pressure, optic neuritis, Grave ophthalmopathy, and orbital pseudotumor may also alter the appearance of the optic nerve/sheath on computed tomography. Certain clinical and computed tomographic features permit distinction of these nonneoplastic tumefactions from tumors

  19. On adiabatic pair potentials of highly charged colloid particles

    Science.gov (United States)

    Sogami, Ikuo S.

    2018-03-01

    Generalizing the Debye-Hückel formalism, we develop a new mean field theory for adiabatic pair potentials of highly charged particles in colloid dispersions. The unoccupied volume and the osmotic pressure are the key concepts to describe the chemical and thermodynamical equilibrium of the gas of small ions in the outside region of all of the colloid particles. To define the proper thermodynamic quantities, it is postulated to take an ensemble averaging with respect to the particle configurations in the integrals for their densities consisting of the electric potential satisfying a set of equations that are derived by linearizing the Poisson-Boltzmann equation. With the Fourier integral representation of the electric potential, we calculate first the internal electric energy of the system from which the Helmholtz free energy is obtained through the Legendre transformation. Then, the Gibbs free energy is calculated using both ways of the Legendre transformation with respect to the unoccupied volume and the summation of chemical potentials. The thermodynamic functions provide three types of pair potentials, all of which are inversely proportional to the fraction of the unoccupied volume. At the limit when the fraction factor reduces to unity, the Helmholtz pair potential turns exactly into the well known Derjaguin-Landau-Verwey-Overbeek repulsive potential. The Gibbs pair potential possessing a medium-range strong repulsive part and a long-range weak attractive tail can explain the Schulze-Hardy rule for coagulation in combination with the van der Waals-London potential and describes a rich variety of phenomena of phase transitions observed in the dilute dispersions of highly charged particles.

  20. Behavioral Model of High Performance Camera for NIF Optics Inspection

    International Nuclear Information System (INIS)

    Hackel, B M

    2007-01-01

    The purpose of this project was to develop software that will model the behavior of the high performance Spectral Instruments 1000 series Charge-Coupled Device (CCD) camera located in the Final Optics Damage Inspection (FODI) system on the National Ignition Facility. NIF's target chamber will be mounted with 48 Final Optics Assemblies (FOAs) to convert the laser light from infrared to ultraviolet and focus it precisely on the target. Following a NIF shot, the optical components of each FOA must be carefully inspected for damage by the FODI to ensure proper laser performance during subsequent experiments. Rapid image capture and complex image processing (to locate damage sites) will reduce shot turnaround time; thus increasing the total number of experiments NIF can conduct during its 30 year lifetime. Development of these rapid processes necessitates extensive offline software automation -- especially after the device has been deployed in the facility. Without access to the unique real device or an exact behavioral model, offline software testing is difficult. Furthermore, a software-based behavioral model allows for many instances to be running concurrently; this allows multiple developers to test their software at the same time. Thus it is beneficial to construct separate software that will exactly mimic the behavior and response of the real SI-1000 camera

  1. KOP program for calculating cross sections of neutron and charged particle interactions with atomic nuclei using the optical model

    International Nuclear Information System (INIS)

    Grudzevich, O.D.; Zelenetskij, A.V.; Pashchenko, A.B.

    1986-01-01

    The last version of the KOP program for calculating cross sections of neutron and charged particle interaction with atomic nuclei within the scope of the optical model is described. The structure and program organization, library of total parameters of the optical potential, program identificators and peculiarities of its operation, input of source data and output of calculational results for printing are described in detail. The KOP program is described in Fortran- and adapted for EC-1033 computer

  2. High ion charge states in a high-current, short-pulse, vacuum ARC ion sources

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1996-01-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1-4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several μs) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  3. High ion charge states in a high-current, short-pulse, vacuum arc ion source

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.; MacGill, R.; Dickinson, M.

    1995-09-01

    Ions of the cathode material are formed at vacuum arc cathode spots and extracted by a grid system. The ion charge states (typically 1--4) depend on the cathode material and only little on the discharge current as long as the current is low. Here the authors report on experiments with short pulses (several micros) and high currents (several kA); this regime of operation is thus approaching a more vacuum spark-like regime. Mean ion charge states of up to 6.2 for tungsten and 3.7 for titanium have been measured, with the corresponding maximum charge states of up to 8+ and 6+, respectively. The results are discussed in terms of Saha calculations and freezing of the charge state distribution

  4. Advances in imaging and electron physics optics of charged particle analyzers

    CERN Document Server

    Hawkes, Peter W

    2011-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. Contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Invaluable reference and guide for physicists, engineers and mathematicians.

  5. Advances in imaging and electron physics optics of charged particle analyzers

    CERN Document Server

    Hawkes, Peter W

    2011-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. * Contributions from leading international scholars and industry experts * Discusses hot topic areas and presents current and future research trends * Invaluable reference and guide for physicists, engineers and mathematicians.

  6. High speed all-silicon optical modulator

    International Nuclear Information System (INIS)

    Marris-Morini, Delphine; Le Roux, Xavier; Pascal, Daniel; Vivien, Laurent; Cassan, Eric; Fedeli, Jean Marc; Damlencourt, Jean Francois; Bouville, David; Palomo, Jose; Laval, Suzanne

    2006-01-01

    Electrorefractive effect is experimentally demonstrated in an all-silicon optical structure. A highly doped Si P + layer is embedded in the intrinsic region of a PIN diode integrated in a SOI waveguide. Holes are confined at equilibrium around the P + layer. By applying a reverse bias to the diode, electrical field sweeps the carriers out of the active region. Free carrier concentration variations are responsible for local refractive index variations leading to an effective index variation of the waveguide optical mode and to an optical absorption variation. As a figure of merit, the product V π L π , determined from the measured effective index variation, is equal to 3.1 V cm. Furthermore, the device performances have theoretically been investigated. Estimations show that V π L π as small as 1 V cm are feasible using optimized structures. Response times lower than 2 ps are predicted, which gives the possibility to achieve very high-speed modulation. Furthermore, a temperature increases from 300 to 400 K does not change the index variation amplitude, and despite the carrier mobility reduction, response times are still lower than 2 ps

  7. High-definition optical coherence tomography

    DEFF Research Database (Denmark)

    Boone, Marc; Norrenberg, Sarah; Jemec, Gregor

    2013-01-01

    to those described for reflectance confocal microscopy but with the advantages not only to visualize individual cells up to a depth of 570 μm but also in both slice and en face mode. An adapted algorithmic method for pattern analysis of common inflammatory skin diseases could be proposed. This new......High-definition optical coherence tomography (HD-OCT) is a non-invasive technique for morphological investigation of tissue with cellular resolution filling the imaging gap between reflectance confocal microscopy and conventional optical coherence tomography. The aim of this study is first...... dermatitis. Additional studies to test the sensitivity and specificity of the proposed algorithm for pattern analysis are essential. The other categories of Ackerman's pattern recognition need to be evaluated. This study provides a set of morphological features generated by HD-OCT imaging very similar...

  8. Narrow optical linewidths and spin pumping on charge-tunable close-to-surface self-assembled quantum dots in an ultrathin diode

    Science.gov (United States)

    Löbl, Matthias C.; Söllner, Immo; Javadi, Alisa; Pregnolato, Tommaso; Schott, Rüdiger; Midolo, Leonardo; Kuhlmann, Andreas V.; Stobbe, Søren; Wieck, Andreas D.; Lodahl, Peter; Ludwig, Arne; Warburton, Richard J.

    2017-10-01

    We demonstrate full charge control, narrow optical linewidths, and optical spin pumping on single self-assembled InGaAs quantum dots embedded in a 162.5 -nm -thin diode structure. The quantum dots are just 88 nm from the top GaAs surface. We design and realize a p -i -n -i -n diode that allows single-electron charging of the quantum dots at close-to-zero applied bias. In operation, the current flow through the device is extremely small resulting in low noise. In resonance fluorescence, we measure optical linewidths below 2 μ eV , just a factor of 2 above the transform limit. Clear optical spin pumping is observed in a magnetic field of 0.5 T in the Faraday geometry. We present this design as ideal for securing the advantages of self-assembled quantum dots—highly coherent single-photon generation, ultrafast optical spin manipulation—in the thin diodes required in quantum nanophotonics and nanophononics applications.

  9. High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems

    International Nuclear Information System (INIS)

    Ghazi, M.E.

    2002-01-01

    Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd

  10. Charge state distributions from highly charged ions channeled at a metal surface

    International Nuclear Information System (INIS)

    Folkerts, L.; Meyer, F.W.; Schippers, S.

    1994-01-01

    The vast majority of the experimental work in the field of multicharged ion-surface interactions, to date, has focused on x-ray and particularly on electron emission. These experiments include measurements of the total electron yield, the emission statistics of the electrons, and, most of all, the electron energy distributions. So far, little attention has been paid to the fate of the multicharged projectile ions after the scattering. To our knowledge, the only measurement of the charge state distribution of the scattered ions is the pioneering experiment of de Zwart et al., who measured the total yield of scattered 1+, 2+, and 3+ ions as a function of the primary charge state q (q = 1--11) for 20 key Ne, Ar, and Kr ions after reflection from a polycrystalline tungsten target. Their main finding is the sudden onset of scattered 3+ ions when inner-shell vacancies are present in the primary particles. This suggests that a certain fraction of the inner-shell vacancies survives the entire collision event, and decays via autoionization on the outgoing path. Since the projectiles scattered in the neutral charge state could not be detected in the experiment of de Zwart et al., they were not able to provide absolute charge state fractions. In our present experiment, we focus on the scattered projectiles, measuring both the final charge state and the total scattering angle with a single 2D position sensitive detector (PSD). This method gives us the number of positive, as well as neutral and negative, scattered ions, thus allowing us to extract absolute charge state fractions. Using a well-prepared single Au(110) crystal and a grazing incidence geometry, we were able to observe surface channeling along the [001] channels

  11. High-order beam optics - an overview

    International Nuclear Information System (INIS)

    Heighway, E.A.

    1989-01-01

    Beam-transport codes have been around for as long as thirty years and high order codes, second-order at least, for close to twenty years. Before this period of design-code development, there was considerable high-order treatment, but it was almost entirely analytical. History has a way of repeating itself, and the current excitement in the field of high-order optics is based on the application of Lie algebra and the so-called differential algebra to beam-transport codes, both of which are highly analytical in foundation. The author will describe some of the main design tools available today, giving a little of their history, and will conclude by trying to convey some of the excitement in the field through a brief description of Lie and differential algebra. 30 refs., 7 figs., 1 tab

  12. STM and transport measurements of highly charged ion modified materials

    International Nuclear Information System (INIS)

    Pomeroy, J.M.; Grube, H.; Perrella, A.C.; Gillaspy, J.D.

    2007-01-01

    Careful measurements of highly charged ions (HCIs) colliding with gases and surfaces have provided glimpses of intense electronic interactions, but a comprehensive model for the interaction mechanisms, time scales, and resultant nano-features that bridges materials systems is yet to be realized. At the National Institute of Standards and Technology (NIST) electron beam ion trap (EBIT) facility, new apparatus is now connected to the HCI beamline to allow preparation of clean, atomically flat surfaces of single crystals, e.g. gold, tungsten and silicon, and deposition and patterning of thin films, e.g. high resistivity oxides, ferromagnetic metals, normal metals and superconductors. Experiments reported here focus on the electronic and morphological structure of HCI induced nano-features. Current activities are focused on using in situ scanning tunneling microscope (STM) on Au(1 1 1) and (separately) ex situ transport measurements to study electronic properties within HCI modified magnetic multilayer systems. Specifically, we are fabricating magnetic multilayers similar to magnetic tunnel junctions (MTJs) (important in advanced magnetic field sensors and superconducting Josephson junction devices) and using HCIs to adjust critical electronic properties. The electrical response of the tunnel junction to HCIs provides a novel approach to performing HCI-induced nanostructure ensemble measurements

  13. High-Order Dielectric Metasurfaces for High-Efficiency Polarization Beam Splitters and Optical Vortex Generators

    Science.gov (United States)

    Guo, Zhongyi; Zhu, Lie; Guo, Kai; Shen, Fei; Yin, Zhiping

    2017-08-01

    In this paper, a high-order dielectric metasurface based on silicon nanobrick array is proposed and investigated. By controlling the length and width of the nanobricks, the metasurfaces could supply two different incremental transmission phases for the X-linear-polarized (XLP) and Y-linear-polarized (YLP) light with extremely high efficiency over 88%. Based on the designed metasurface, two polarization beam splitters working in high-order diffraction modes have been designed successfully, which demonstrated a high transmitted efficiency. In addition, we have also designed two vortex-beam generators working in high-order diffraction modes to create vortex beams with the topological charges of 2 and 3. The employment of dielectric metasurfaces operating in high-order diffraction modes could pave the way for a variety of new ultra-efficient optical devices.

  14. Effects of High Temperature and Thermal Cycling on the Performance of Perovskite Solar Cells: Acceleration of Charge Recombination and Deterioration of Charge Extraction

    KAUST Repository

    Sheikh, Arif D.

    2017-09-18

    In this work, we investigated the effects of high operating temperature and thermal cycling on the photovoltaic performance of perovskite solar cells (PSCs) with a typical mesostructured (m)-TiO2-CH3NH3PbI3-xClx-spiro-OMeTAD architecture. After carrying out temperature-dependent grazing incidence wide-angle X-ray scattering (GIWAXS), in-situ X-ray diffraction (XRD) and optical absorption experiments, thermal durability of PSCs was tested by subjecting the devices to repetitive heating to 70 °C and cooling to room temperature (20 °C). An unexpected regenerative effect was observed after the first thermal cycle; the average power conversion efficiency (PCE) increased by approximately 10 % in reference to the as-prepared device. This increase of PCE was attributed to the heating-induced improvement of crystallinity and p-doping in the hole-transporter, Spiro-OMeTAD, which promotes the efficient extraction of photo-generated carriers. However, further thermal cycles produced a detrimental effect on the photovoltaic performance of PSCs with short-circuit current and fill factor degrading faster than the open-circuit voltage. Similarly, the photovoltaic performance of PSCs degraded at high operation temperatures; both short-circuit current and open-circuit voltage decreased with increasing temperature, but the temperature-dependent trend of fill factor was opposite. Our impedance spectroscopy analysis revealed a monotonous increase of charge transfer resistance and a concurrent decrease of charge recombination resistance with increasing temperature, indicating high recombination of charge carriers. Our results revealed that both thermal cycling and high temperatures produce irreversible detrimental effects on the PSC performance due to the deteriorated interfacial photo-carrier extraction. The present findings suggest that development of robust charge transporters and proper interface engineering are critical for the deployment of perovskite photovoltaics in harsh

  15. Excitation and ionization of highly charged ions by electron impact

    International Nuclear Information System (INIS)

    Sampson, D.H.

    1989-01-01

    Two approaches for very rapid calculation of atomic data for high temperature plasma modeling have been developed. The first uses hydrogenic basis states and has been developed and applied in many papers discussed in previous progress reports. Hence, it is only briefly discussed here. The second is a very rapid, yet accurate, fully relativistic approach that has been developed over the past two or three years. It is described in more detail. Recently it has been applied to large scale production of atomic data. Specifically, it has been used to calculate relativistic distorted wave collision strengths and oscillator strengths for the following: all transitions from the ground level to the n=3 and 4 excited levels in the 71 Neon-like ions with nuclear charge number Z in the range 22 ≤ Z ≤ 92; all transitions among the 2s 1/2 , 2p 1/2 and 2p 3/2 levels and from them to all nlj levels with n=3,4 and 5 in the 85 Li-like ions with 8 ≤ Z ≤ 92; all transitions among the 3s 1/2 , 3p 3/2 , 3d 3/2 and 3d 5/2 levels and from them to all nlj levels with n=4 and 5 in the 71 Na-like ions with 22 ≤ Z ≤ 92; and all transitions among 4s 1/2 , 4p 1/2 , 4p 3/2 , 4d 3/2 , 4d 5/2 , 4f 5/2 and 4f 7/2 levels and from them to all nlj levels with n=5 in the 33 Cu-like ions with 60 ≤ Z ≤ 92. Also the program has been extended to give cross-sections for excitation to specific magnetic sublevels of the target ion by an electron beam and very recently it has been extended to give relativistic distorted wave cross sections for ionization of highly charged ions by electron impact

  16. On the investigation of electronic defect states in ZnO thin films by space charge spectroscopy with optical excitation

    Science.gov (United States)

    Schmidt, Matthias; Wenckstern, Holger von; Pickenhain, Rainer; Grundmann, Marius

    2012-09-01

    Electronic defect states in a n-type conducting zinc oxide thin film sample were investigated by means of space charge spectroscopy focussing on levels in the midgap region as well as on hole traps. To overcome the experimental difficulties arising from the wide bandgap and the lack of p-type conduction, optical excitation was employed to measure the emission of trapped charge carriers from these levels. Therefore - besides deep-level transient spectroscopy measurements - photo-capacitance, optically chopped photo-current, minority carrier transient spectroscopy, and optical capacitance-voltage experiments were conducted. In doing so, a midgap level labelled T4, and hole traps labelled TH1 and TH2 were detected. In the case of T4 and TH1 the photo-ionisation cross-section spectra were determined.

  17. Analysis on the Effect of Sensor Views in Image Reconstruction Produced by Optical Tomography System Using Charge-Coupled Device.

    Science.gov (United States)

    Jamaludin, Juliza; Rahim, Ruzairi Abdul; Fazul Rahiman, Mohd Hafiz; Mohd Rohani, Jemmy

    2018-04-01

    Optical tomography (OPT) is a method to capture a cross-sectional image based on the data obtained by sensors, distributed around the periphery of the analyzed system. This system is based on the measurement of the final light attenuation or absorption of radiation after crossing the measured objects. The number of sensor views will affect the results of image reconstruction, where the high number of sensor views per projection will give a high image quality. This research presents an application of charge-coupled device linear sensor and laser diode in an OPT system. Experiments in detecting solid and transparent objects in crystal clear water were conducted. Two numbers of sensors views, 160 and 320 views are evaluated in this research in reconstructing the images. The image reconstruction algorithms used were filtered images of linear back projection algorithms. Analysis on comparing the simulation and experiments image results shows that, with 320 image views giving less area error than 160 views. This suggests that high image view resulted in the high resolution of image reconstruction.

  18. Study of proton polarization in charge exchange process on optically oriented sodium atoms

    International Nuclear Information System (INIS)

    Zelenskij, A.N.; Kokhanovskij, S.A.

    1984-01-01

    Using high-power adjustable dye lasers for electron spin orientation in a charge-exchange target enables to significantly increase the proton polarization efficiency. A device is described that permits to avoid growth of the polarized proton beam emittance in a charge-exchange process in a strong magnetic field. The devise main feature is the use of an intensive source of neutral hydrogen atoms and the presence of a helium additional charge-exchange target which actualy is a proton ''source''. The helium charge-exchange cell is placed in the same magnetic field of a solenoid where a cell with oriented sodium is placed, a polarized electron being captured by a proton in the latter cell. In this case the beam at the solenoid inlet and outlet is in a neutral state; emittance growth related to the effect of end magnetic fields is not observed. The device after all prouduces polarized protons, their polarization degree is measured and the effect of various factors on polarization degree is studied. The description of the laser source and laser system is given. Measurement results have shown the beam intensity of neutral 7 keV atoms which passed through a polarizer to be 2 mA. The proton current doesn't depend. On the beeld fin the region of chrge exchange for the 8 kGs magnetic field. The degree of sodium polarization was 80% and polarized proton current approximately 70 μA at a temperature of the polarized sodium cell corresponding to the density of sodium vapar approximately 3x10 13 at/cm 2

  19. Energy of charged states in the acetanilide crystal: Trapping of charge-transfer states at vacancies as a possible mechanism for optical damage

    Science.gov (United States)

    Tsiaousis, D.; Munn, R. W.

    2004-04-01

    Calculations for the acetanilide crystal yield the effective polarizability (16.6 Å3), local electric field tensor, effective dipole moment (5.41 D), and dipole-dipole energy (-12.8 kJ/mol). Fourier-transform techniques are used to calculate the polarization energy P for a single charge in the perfect crystal (-1.16 eV); the charge-dipole energy WD is zero if the crystal carries no bulk dipole moment. Polarization energies for charge-transfer (CT) pairs combine with the Coulomb energy EC to give the screened Coulomb energy Escr; screening is nearly isotropic, with Escr≈EC/2.7. For CT pairs WD reduces to a term δWD arising from the interaction of the charge on each ion with the change in dipole moment on the other ion relative to the neutral molecule. The dipole moments calculated by density-functional theory methods with the B3LYP functional at the 6-311++G** level are 3.62 D for the neutral molecule, changing to 7.13 D and 4.38 D for the anion and cation, relative to the center of mass. Because of the large change in the anion, δWD reaches -0.9 eV and modifies the sequence of CT energies markedly from that of Escr, giving the lowest two CT pairs at -1.98 eV and -1.41 eV. The changes in P and WD near a vacancy are calculated; WD changes for the individual charges because the vacancy removes a dipole moment and modifies the crystal dielectric response, but δWD and EC do not change. A vacancy yields a positive change ΔP that scatters a charge or CT pair, but the change ΔWD can be negative and large enough to outweigh ΔP, yielding traps with depths that can exceed 150 meV for single charges and for CT pairs. Divacancies yield traps with depths nearly equal to the sum of those produced by the separate vacancies and so they can exceed 300 meV. These results are consistent with a mechanism of optical damage in which vacancies trap optically generated CT pairs that recombine and release energy; this can disrupt the lattice around the vacancy, thereby favoring

  20. Equilibrium charge state distributions of high energy heavy ions

    International Nuclear Information System (INIS)

    Clark, R.B.; Grant, I.S.; King, R.; Eastham, D.A.; Joy, T.

    1976-01-01

    Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)

  1. IBSIMU: A three-dimensional simulation software for charged particle optics

    Energy Technology Data Exchange (ETDEWEB)

    Kalvas, T.; Tarvainen, O.; Ropponen, T.; Steczkiewicz, O.; Aerje, J. [Department of Physics, University of Jyvaeskylae, Jyvaeskylae 40500 (Finland); Clark, H. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States)

    2010-02-15

    A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equation solver based on fast stabilized biconjugate gradient method with ILU0 preconditioner for solving electrostatic fields. A generally accepted nonlinear plasma model is used for plasma extraction. Magnetic fields can be imported to the simulations from other programs. The particle trajectories are solved using adaptive Runge-Kutta method. Steady-state and time-dependent problems can be modeled in cylindrical coordinates, two-dimensional (slit) geometry, or full 3D. The code is used via C++ programming language for versatility but it features an interactive easy-to-use postprocessing tool for diagnosing fields and particle trajectories. The open source distribution and public documentation make the code well suited for scientific use. IBSIMU has been used for modeling the 14 GHz ECR ion source extraction and for designing a four-electrode extraction for a 2.45 GHz microwave ion source at Jyvaeskylae. A grid extraction has also been designed for producing large uniform beam for creating conditions similar to solar wind. The code has also been used to design a H{sup -} extraction with electron dumping for the Cyclotron Institute of Texas A and M University.

  2. Two-photon processes in highly charged ions

    International Nuclear Information System (INIS)

    Jahrsetz, Thorsten

    2015-01-01

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  3. Quantum interference in laser spectroscopy of highly charged lithiumlike ions

    Science.gov (United States)

    Amaro, Pedro; Loureiro, Ulisses; Safari, Laleh; Fratini, Filippo; Indelicato, Paul; Stöhlker, Thomas; Santos, José Paulo

    2018-02-01

    We investigate the quantum interference induced shifts between energetically close states in highly charged ions, with the energy structure being observed by laser spectroscopy. In this work, we focus on hyperfine states of lithiumlike heavy-Z isotopes and quantify how much quantum interference changes the observed transition frequencies. The process of photon excitation and subsequent photon decay for the transition 2 s →2 p →2 s is implemented with fully relativistic and full-multipole frameworks, which are relevant for such relativistic atomic systems. We consider the isotopes 79+207Pb and 80+209Bi due to experimental interest, as well as other examples of isotopes with lower Z , namely 56+141Pr and 64+165Ho. We conclude that quantum interference can induce shifts up to 11% of the linewidth in the measurable resonances of the considered isotopes, if interference between resonances is neglected. The inclusion of relativity decreases the cross section by 35%, mainly due to the complete retardation form of the electric dipole multipole. However, the contribution of the next higher multipoles (e.g., magnetic quadrupole) to the cross section is negligible. This makes the contribution of relativity and higher-order multipoles to the quantum interference induced shifts a minor effect, even for heavy-Z elements.

  4. Two-photon processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Jahrsetz, Thorsten

    2015-03-05

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  5. High spatial and temporal resolution charge exchange recombination spectroscopy on the HL-2A tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Y. L.; Yu, D. L., E-mail: yudl@swip.ac.cn; Liu, L.; Cao, J. Y.; Sun, A. P.; Ma, Q.; Chen, W. J.; Liu, Yi; Yan, L. W.; Yang, Q. W.; Duan, X. R.; Liu, Yong [Southwestern Institute of Physics, Chengdu 610041 (China); Ida, K. [National Institute for Fusion Science, Toki 509-5292 (Japan); Hellermann, M. von [ITER Diagnostic Team, IO, Route de Vinon sur Verdon, 13115 St Paul lez Durance (France); FOM-Institute for Plasma physics “Rijnhuizen,” Association EURATOM, Trilateral Euregio Cluster, 3430 BE Nieuwegein (Netherlands)

    2014-10-01

    A 32/64-channel charge exchange recombination spectroscopy (CXRS) diagnostic system is developed on the HL-2A tokamak (R = 1.65 m, a = 0.4 m), monitoring plasma ion temperature and toroidal rotation velocity simultaneously. A high throughput spectrometer (F/2.8) and a pitch-controlled fiber bundle enable the temporal resolution of the system up to 400 Hz. The observation geometry and an optimized optic system enable the highest radial resolution up to ~1 cm at the plasma edge. The CXRS system monitors the carbon line emission (C VI, n = 8–7, 529.06 nm) whose Doppler broadening and Doppler shift provide ion temperature and plasma rotation velocity during the neutral beam injection. The composite CX spectral data are analyzed by the atomic data and analysis structure charge exchange spectroscopy fitting (ADAS CXSFIT) code. First experimental results are shown for the case of HL-2A plasmas with sawtooth oscillations, electron cyclotron resonance heating, and edge transport barrier during the high-confinement mode (H-mode)

  6. High energy particle detectors utilizing cryogenic charge storage

    Energy Technology Data Exchange (ETDEWEB)

    Coon, D; Engels, E Jr; Plants, D; Shepard, P F; Yang, Y [Pittsburgh Univ., PA (USA); Sopira, M; Papania, R [Westinghouse Research and Development Labs., Monroeville, PA (USA)

    1984-09-15

    The mechanism of cryogenic charge storage as a method of particle detection is reviewed. A description of a simple multielement strip detector operated in this mode is given, and partial results on its operating characteristics presented.

  7. Optical studies of high quality synthetic diamond

    International Nuclear Information System (INIS)

    Sharp, S.J.

    1999-01-01

    This thesis is concerned with the study of fundamental and defect induced optical properties of synthetic diamond grown using high pressure, high temperature (HPHT) synthesis or chemical vapour deposition (CVD). The primary technique used for investigation is cathodoluminescence (including imaging and decay-time measurements) in addition to other forms of optical spectroscopy. This thesis is timely in that the crystallinity and purity of synthetic diamond has increased ten fold over the last few years. The diamond exciton emission, which is easily quenched by the presence of defects, is studied in high quality samples in detail. In addition the ability now exists to engineer the isotopic content of synthetic diamond to a high degree of accuracy. The experimental chapters are divided as follows: Chapter 2: High resolution, low temperature spectra reveal a splitting of the free-exciton phonon recombination emission peaks and the bound-exciton zero phonon line. Included are measurements of the variation in intensity and decay-time as a function of temperature. Chapter 3: The shift in energy of the phonon-assisted free-exciton phonon replicas with isotopic content has been measured. The shift is in agreement with the results of interatomic force model for phonon scattering due to isotope disorder. Chapter 4: A study of the shift in energy with isotopic content of the diamond of the GR1 band due to the neutral vacancy has allowed a verification of the theoretical predictions due to the Jahn Teller effect. Chapter 5: The spatial distribution of the free-exciton luminescence is studied in HPHT synthetic and CVD diamond. A variation in intensity with distance from the surface is interpreted as a significant non-radiative loss of excitons to the surface. Chapter 6: The decay-times of all known self-interstitial related centres have been measured in order to calculate the concentration of these centres present in electron irradiated diamond. (author)

  8. The interactions of high-energy, highly charged Xe ions with buckyballs

    International Nuclear Information System (INIS)

    Ali, R.; Berry, H.G.; Cheng, S.

    1994-01-01

    Ionization and fragmentation have been measured for C 60 molecules bombarded by highly charged (up to 35+) xenon ions with energies ranging up to 625 MeV. The observed mass distribution of positively charged fragments is explained in terms of a theoretical model indicating that the total interaction cross section contains roughly equal contributions from (a) excitation of the giant plasmon resonance, and (b) large-energy-transfer processes that lead to multiple fragmentation of the molecule. Preliminary results of measurements on VUV photons emitted in these interactions are also presented

  9. The study towards high intensity high charge state laser ion sources.

    Science.gov (United States)

    Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

    2014-02-01

    As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

  10. High pressure fiber optic sensor system

    Science.gov (United States)

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  11. The character of resonant charge exchange involving highly excited atoms

    International Nuclear Information System (INIS)

    Kosarim, A. V.; Smirnov, B. M.; Capitelli, M.; Laricchiuta, A.

    2012-01-01

    We study the process of resonant charge exchange involving excited helium atoms with the principal quantum number n = 5 colliding with the helium ion in the ground state in the collision energy range from thermal up to 10 eV. This information may be important for the analysis of planet atmospheres containing helium, in particular, for Jupiter’s atmosphere, but our basic interest is the transition from the quantum to classical description of this process, where, due to large cross sections, evaluations of the cross sections are possible. For the chosen process, quantum theory allows determining the cross section as a result of a tunnel electron transition, while classical theory accounts for over-barrier electron transitions. The classical theory additionally requires effective transitions between states with close energies. The analysis of these transitions for helium with n = 5 shows that electron momenta and their projections are mixed for a part of the states, while for other states, the mixing is absent. A simple criterion to separate such states is given. In addition, the main contribution to the cross section of resonant charge exchange follows from tunnel electron transitions. As a result, the quantum theory is better for calculating the cross sections of resonant charge exchange than the classical one and also allows finding the partial cross sections of resonant charge exchange, while the classical approach gives the cross section of resonant charge exchange in a simple manner with the accuracy of 20%.

  12. A High-Performance Optical Memory Array Based on Inhomogeneity of Organic Semiconductors.

    Science.gov (United States)

    Pei, Ke; Ren, Xiaochen; Zhou, Zhiwen; Zhang, Zhichao; Ji, Xudong; Chan, Paddy Kwok Leung

    2018-03-01

    Organic optical memory devices keep attracting intensive interests for diverse optoelectronic applications including optical sensors and memories. Here, flexible nonvolatile optical memory devices are developed based on the bis[1]benzothieno[2,3-d;2',3'-d']naphtho[2,3-b;6,7-b']dithiophene (BBTNDT) organic field-effect transistors with charge trapping centers induced by the inhomogeneity (nanosprouts) of the organic thin film. The devices exhibit average mobility as high as 7.7 cm 2 V -1 s -1 , photoresponsivity of 433 A W -1 , and long retention time for more than 6 h with a current ratio larger than 10 6 . Compared with the standard floating gate memory transistors, the BBTNDT devices can reduce the fabrication complexity, cost, and time. Based on the reasonable performance of the single device on a rigid substrate, the optical memory transistor is further scaled up to a 16 × 16 active matrix array on a flexible substrate with operating voltage less than 3 V, and it is used to map out 2D optical images. The findings reveal the potentials of utilizing [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives as organic semiconductors for high-performance optical memory transistors with a facile structure. A detailed study on the charge trapping mechanism in the derivatives of BTBT materials is also provided, which is closely related to the nanosprouts formed inside the organic active layer. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Toward high throughput optical metamaterial assemblies.

    Science.gov (United States)

    Fontana, Jake; Ratna, Banahalli R

    2015-11-01

    Optical metamaterials have unique engineered optical properties. These properties arise from the careful organization of plasmonic elements. Transitioning these properties from laboratory experiments to functional materials may lead to disruptive technologies for controlling light. A significant issue impeding the realization of optical metamaterial devices is the need for robust and efficient assembly strategies to govern the order of the nanometer-sized elements while enabling macroscopic throughput. This mini-review critically highlights recent approaches and challenges in creating these artificial materials. As the ability to assemble optical metamaterials improves, new unforeseen opportunities may arise for revolutionary optical devices.

  14. A modified space charge routine for high intensity bunched beams

    International Nuclear Information System (INIS)

    Lapostolle, P.; Lombardi, A.M.; Tanke, E.; Valero, S.; Garnett, R.W.; Wangler, T.P.

    1996-01-01

    A new routine and a computer code (DYNAC) for the calculation of space charge densities in a new generation of linear accelerators for various industrial applications is presented. The new beam dynamics method used in this code, employs a set of quasi-Liouvillian equations, allowing beam dynamics computations in long and complex structures for electrons, as well as protons and ions. With this new beam dynamics method, the coordinates of particles are known at any position in the accelerating elements, allowing multistep space charge calculations. (K.A.)

  15. Beamline for low-energy transport of highly charged ions at HITRAP

    International Nuclear Information System (INIS)

    Andelkovic, Z.; Herfurth, F.; Kotovskiy, N.; König, K.; Maaß, B.; Murböck, T.; Neidherr, D.; Schmidt, S.; Steinmann, J.; Vogel, M.; Vorobjev, G.

    2015-01-01

    A beamline for transport of highly charged ions with energies as low as a few keV/charge has been constructed and commissioned at GSI. Complementary to the existing infrastructure of the HITRAP facility for deceleration of highly charged ions from the GSI accelerator, the new beamline connects the HITRAP ion decelerator and an EBIT with the associated experimental setups. Therefore, the facility can now transport the decelerated heavy highly charged ions to the experiments or supply them offline with medium-heavy highly charged ions from the EBIT, both at energies as low as a few keV/charge. Here we present the design of the 20 m long beamline with the corresponding beam instrumentation, as well as its performance in terms of energy and transport efficiency

  16. Energy gaps, valence and conduction charge densities and optical properties of GaAs1‑xPx

    Science.gov (United States)

    Al-Hagan, O. A.; Algarni, H.; Bouarissa, N.; Alhuwaymel, T. F.; Ajmal Khan, M.

    2018-04-01

    The electronic structure and its derived valence and conduction charge distributions along with the optical properties of zinc-blende GaAs1‑xPx ternary alloys have been studied. The calculations are performed using a pseudopotential approach under the virtual crystal approximation (VCA) which takes into account the compositional disorder effect. Our findings are found to be generally in good accord with experiment. The composition dependence of direct and indirect bandgaps showed a clear bandgap bowing. The nature of the gap is found to depend on phosphorous content. The bonding and ionicity of the material of interest have been examined in terms of the anti-symmetric gap and charge densities. The variation in the optical constants versus phosphorous concentration has been discussed. The present investigation may give a useful applications in infrared and visible spectrum light emitters.

  17. Investigation of the energy loss and the charge state of high energy heavy ions in a hydrogen plasma

    International Nuclear Information System (INIS)

    Dietrich, K.G.

    1991-07-01

    For heavy ions with energy of 1.4 to 5.9 MeV/u the energy loss and charge state after transmission through a totally ionized hydrogen plasma are investigated. Plasma target was a Z-pinch device incorporated in the beam optics of the accelerator by a pumping system. In the 20 cm long pinch hydrogen plasmas with densities up to 1.5x10 19 cm -3 and temperatures above 5 eV are produced, with ionization efficiency higher than 99%. The ions pass the plasma on the symmetry axis of the plasma column through small apertures in the electrodes. The energy loss was measured by time-of-flight method, the plasma density by interferometry along the pinch axis. For the first time the ion charge after transmission through the plasma has been determined by a charge spectrometer being a combination of a dipole magnet and a position sensitive detector with high time resolution. A growth of the average charge of heavy ions in plasma higher than the equilibrium charge in cold gas was discovered, caused by a reduction of electron capture by fast heavy ions in ionized matter. The electron loss rates in plasma and cold gas are equal. (orig./AH) [de

  18. Charging of Dust Grains in a Nuclear-Induced Plasma at High Pressures

    International Nuclear Information System (INIS)

    Pal’, A. F.; Starostin, A. N.; Filippov, A. V.

    2001-01-01

    The process of dust-grain charging in plasmas produced by radioactive decay products or spontaneous fission fragments in air and xenon at high pressures is studied numerically in the hydrodynamic approximation. It is shown that, at sufficiently high rates of gas ionization, the dust grains in air are charged by electrons rather than ions, so that the grain charge in air is comparable to that in electropositive gases. The results of numerical calculations based on a complete model agree well with the experimental data. The time evolution of the grain charge is investigated, and the characteristic time scales on which the grains acquire an electric charge are established. The validity of approximate theories of dust-grain charging in electropositive and electronegative gases at high pressures is examined

  19. The interactions of high-energy, highly-charged ions with fullerenes

    International Nuclear Information System (INIS)

    Ali, R.; Berry, H.G.; Cheng, S.

    1996-01-01

    In 1985, Robert Curl and Richard Smalley discovered a new form of carbon, the fullerene, C 60 , which consists of 60 carbon atoms in a closed cage resembling a soccer ball. In 1990, Kritschmer et al. were able to make macroscopic quantities of fullerenes. This has generated intense activity to study the properties of fullerenes. One area of research involves collisions between fullerenes and atoms, ions or electrons. In this paper we describe experiments involving interactions between fullerenes and highly charged ions in which the center-of-mass energies exceed those used in other work by several orders of magnitude. The high values of projectile velocity and charge state result in excitation and decay processes differing significantly from those seen in studies 3 at lower energies. Our results are discussed in terms of theoretical models analogous to those used in nuclear physics and this provides an interesting demonstration of the unity of physics

  20. Measurements of the Properties of Highly-charged high-Z ions

    International Nuclear Information System (INIS)

    Augustine J. Smith, Ph.D.

    2007-01-01

    We had proposed carrying out a systematic experimental investigation of the atomic physics of highly charged, high-Z ions, produced in the Lawrence Livermore National Laboratory LLNL electron beam ion trap (EBIT-I) in its high energy mode, superEBIT. In particular we were going to accurately measure line positions for Δn=0 transitions in few electron high-Z ions; this was meant to enable us to investigate relativistic and quantum electrodynamics QED contributions to the energy levels as well as the nuclear properties of heavy ions. We were also going to measure cross sections for various electron-ion interactions, the degree of polarization of emitted x-rays, and radiation cooling rates of various ionization stages of highly charged, high-Z ions. This would enable us to study fundamental atomic physics of high-Z ions at relativistic electron impact energies and in the intense nuclear fields of highly ionized, high-Z ions. This would extend previous measurements we have carried out to a regime where there is a paucity of good data. These measurements were expected to generate increased theoretical interest and activity in this area. The project will extend a very successful collaboration between Morehouse College (MC) and a national laboratory LLNL, Minority student training and development are major components of the proposal

  1. QED in highly-charged high Z ions - experiments at the storage ring ESR

    International Nuclear Information System (INIS)

    Mokler, P.H.

    1996-01-01

    A survey on the fundamental structure aspects of very heavy few -electron ions, in particular H-like systems, is presented. Special emphasis is given to contribution from quantum-electro-dynamics at strong central potentials. The technical possibilities to produce highly-charged heavy ions are reviewed and the ground-state Lamb-shift experiments performed at the heavy ion storage ring ESR are summarized. A short outlook on further developments in this field is added. (author). 23 refs, 9 figs

  2. Rendering high charge density of states in ionic liquid-gated MoS 2 transistors

    NARCIS (Netherlands)

    Lee, Y.; Lee, J.; Kim, S.; Park, H.S.

    2014-01-01

    We investigated high charge density of states (DOS) in the bandgap of MoS2 nanosheets with variable temperature measurements on ionic liquid-gated MoS2 transistors. The thermally activated charge transport indicates that the electrical current in the two-dimensional MoS 2 nanosheets under high

  3. Ionization of highly charged iodine ions near the Bohr velocity

    International Nuclear Information System (INIS)

    Zhou, Xianming; Cheng, Rui; Lei, Yu; Sun, Yuanbo; Ren, Jieru; Liu, Shidong; Deng, Jiachuan; Zhao, Yongtao; Xiao, Guoqing

    2015-01-01

    We have measured the L-shell X-rays of iodine from the collisions of 3 MeV I q+(q=15,20,22,25,26) ions with an iron target. It is found that the X-ray yield decreases with the increasing initial charge state. The energy of the subshell X-ray has a blue shift, which is independent of the projectile charge state. In addition, the relative intensity ratios of Lβ 1,3,4 and Lβ 2,15 to Lα 1,2 X-ray are obtained and compared with the theoretical calculations. That they are larger than for a singly ionized atom can be understood by the multiple ionization effect of the outer-shell electrons

  4. Peltier effect in multilayered nanopillars under high density charge current

    International Nuclear Information System (INIS)

    Gravier, L; Fukushima, A; Kubota, H; Yamamoto, A; Yuasa, S

    2006-01-01

    From the basic equations of thermoelectricity, we model the thermal regimes that develop in multilayered nanopillar elements experiencing continuous charge currents. The energy conservation principle was applied to all layer-layer and layer-electrode junctions. The obtained set of equations was solved to derive the temperature of each junction. The contribution of the Peltier effect is included in an effective resistance. This model gives satisfactory fits to experimental data obtained on a series of reference nanopillar elements

  5. Superconductivity and charge transfer excitations in high Tc superconductors

    International Nuclear Information System (INIS)

    Balseiro, C.A.; Alascio, B.; Gagliano, E.; Rojo, A.

    1988-01-01

    We present some numerical results to show that in a simple model which includes Cu 3d and O 2p orbitals together with inter and intra atomic correlations pairing between holes can occur due to charge transfer excitations. We present also a simple approximation to derive an effective Hamiltonian containing an interaction between particles which is attractive for some values of the different microscopic parameters

  6. High density thermite mixture for shaped charge ordnance disposal

    OpenAIRE

    Tamer Elshenawy; Salah Soliman; Ahmed Hawass

    2017-01-01

    The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using col...

  7. Charge identification of highly ionizing particles in desensitized nuclear emulsion using high speed read-out system

    International Nuclear Information System (INIS)

    Toshito, T.; Kodama, K.; Yusa, K.; Ozaki, M.; Amako, K.; Kameoka, S.; Murakami, K.; Sasaki, T.; Aoki, S.; Ban, T.; Fukuda, T.; Naganawa, N.; Nakamura, T.; Natsume, M.; Niwa, K.; Takahashi, S.; Kanazawa, M.; Kanematsu, N.; Komori, M.; Sato, S.; Asai, M.; Koi, T.; Fukushima, C.; Ogawa, S.; Shibasaki, M.; Shibuya, H.

    2006-01-01

    We performed an experimental study of charge identification of heavy ions from helium to carbon having energy of about 290MeV/u using an emulsion chamber. Emulsion was desensitized by means of forced fading (refreshing) to expand a dynamic range of response to highly charged particles. For the track reconstruction and charge identification, the fully automated high speed emulsion read-out system, which was originally developed for identifying minimum ionizing particles, was used without any modification. Clear track by track charge identification up to Z=6 was demonstrated. The refreshing technique has proved to be a powerful technique to expand response of emulsion film to highly ionizing particles

  8. TOCUSO: Test of Conceptual Understanding on High School Optics Topics

    Science.gov (United States)

    Akarsu, Bayram

    2012-01-01

    Physics educators around the world often need reliable diagnostic materials to measure students' understanding of physics concept in high school. The purpose of this study is to evaluate a new diagnostic tool on High School Optics concept. Test of Conceptual Understanding on High School Optics (TOCUSO) consists of 25 conceptual items that measures…

  9. Tunability of Open-Shell Character, Charge Asymmetry, and Third-Order Nonlinear Optical Properties of Covalently Linked (Hetero)Phenalenyl Dimers.

    Science.gov (United States)

    Minamida, Yuka; Kishi, Ryohei; Fukuda, Kotaro; Matsui, Hiroshi; Takamuku, Shota; Yamane, Masaki; Tonami, Takayoshi; Nakano, Masayoshi

    2018-02-06

    Tunability of the open-shell character, charge asymmetry, and third-order nonlinear optical (NLO) properties of covalently linked (hetero)phenalenyl dimers are investigated by using the density functional theory method. By changing the molecular species X and substitution position (i, j) for the linker part, a variety of intermonomer distances R and relative alignments between the phenalenyl dimers can be realized from the geometry optimizations, resulting in a wide-range tuning of diradical character y and charge asymmetry. It is found that the static second hyperpolarizabilities along the stacking direction, γ yyyy , are one-order enhanced for phenalenyl dimer systems exhibiting intermediate y, a feature that is in good agreement with the "y-γ correlation". By replacing the central carbon atoms of the phenalenyl rings with a boron or a nitrogen, we have also designed covalently linked heterophenalenyl dimers. The introduction of such a charge asymmetry to the open-shell systems, which leads to closed-shell ionic ground states, is found to further enhance the γ yyyy values of the systems having longer intermonomer distance R with intermediate ionic character, that is, charge asymmetry. The present results demonstrate a promising potential of covalently linked NLO dimers with intermediate open-shell/ionic characters as a new building block of highly efficient NLO systems. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Generation of initial kinetic distributions for simulation of long-pulse charged particle beams with high space-charge intensity

    Directory of Open Access Journals (Sweden)

    Steven M. Lund

    2009-11-01

    Full Text Available Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel—both in terms of low-order rms (envelope properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including the following: the Kapchinskij-Vladimirskij (KV equilibrium, continuous-focusing equilibria with specific detailed examples, and various nonequilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of standard accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear focusing, single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for noncontinuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulations that more precisely probe intrinsic stability properties and machine performance.

  11. High-temperature fiber optic pressure sensor

    Science.gov (United States)

    Berthold, J. W.

    1984-01-01

    Attention is given to a program to develop fiber optic methods to measure diaphragm deflection. The end application is intended for pressure transducers capable of operating to 540 C. In this paper are reported the results of a laboratory study to characterize the performance of the fiber-optic microbend sensor. The data presented include sensitivity and spring constant. The advantages and limitations of the microbend sensor for static pressure measurement applications are described. A proposed design is presented for a 540 C pressure transducer using the fiber optic microbend sensor.

  12. Preparation of cold Mg+ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

    International Nuclear Information System (INIS)

    Cazan, Radu Mircea

    2012-02-01

    The bound electrons in hydrogen-like or lithium-like heavy ions experience extremely strong electric and magnetic fields in the surrounding of the nucleus. Laser spectroscopy of the ground-state hyperfine splitting in the lead region provides a sensitive tool to test strong-field quantum electro dynamics (QED), especially in the magnetic sector. Previous measurements on hydrogen-like systems performed in an electron-beam ion trap (EBIT) or at the experimental storage ring (ESR) were experimentally limited in accuracy due to statistics, the large Doppler broadening and the ion energy. The full potential of the QED test can only be exploited if measurements for hydrogen- and lithium-like ions are performed with accuracy improved by 2-3 orders of magnitude. Therefore, the new Penning trap setup SPECTRAP - dedicated for laser spectroscopy on trapped and cooled highly charged ions - is currently commissioned at GSI Darmstadt. Heavy highly charged ions will be delivered to this trap by the HITRAP facility in the future. SPECTRAP is a cylindrical Penning trap with axial access for external ion injection and radial optical access mounted inside a cold-bore superconducting Helmholtz-type split-coil magnet. To reach the targeted accuracy in laser spectroscopy, an efficient and fast cooling process for the highly charged ions must be employed. This can be realized by sympathetic cooling with a cloud of laser-cooled light ions. Within this thesis work, a laser system and an ion source for the production of such a 24 Mg + ion cloud was developed and commissioned at SPECTRAP. An all-solid-state laser system for the generation of 279.6 nm light was designed and built. It consists of a fiber laser at 1118.5 nm followed by frequency quadrupling using two successive second-harmonic generation stages with actively stabilized ring resonators and nonlinear crystals. The laser system can deliver more than 15 mW of UV laser power under optimal conditions and requires little maintenance

  13. High Performance Graded Index Polymer Optical Fibers

    National Research Council Canada - National Science Library

    Garito, Anthony

    1998-01-01

    ...) plastic optical fibers (POF) and graded index (GI) POFs are reported. A set of criteria and analyses of physical parameters are developed in context to the major issues of POF applications in short-distance communication systems...

  14. Pricing Strategy in Online Retailing Marketplaces of Homogeneous Goods: Should High Reputation Seller Charge More?

    Science.gov (United States)

    Liu, Yuewen; Wei, Kwok Kee; Chen, Huaping

    There are two conflicting streams of research findings on pricing strategy: one is high reputation sellers should charge price premium, while the other is high reputation sellers should charge relatively low price. Motivated by this confliction, this study examines pricing strategy in online retailing marketplace of homogeneous goods. We conduct an empirical study using data collected from a dominant online retailing marketplace in China. Our research results indicate that, in online retailing marketplace of homogeneous goods, high reputation sellers should charge relatively low price, because the consumers of high reputation sellers are more price sensitive than the consumers of low reputation sellers.

  15. High Charge State Ions Extracted from Metal Plasmas in the Transition Regime from Vacuum Spark to High Current Vacuum Arc

    International Nuclear Information System (INIS)

    Yushkov, Georgy Yu.; Anders, A.

    2008-01-01

    Metal ions were extracted from pulsed discharge plasmas operating in the transition region between vacuum spark (transient high voltage of kV) and vacuum arc (arc voltage ∼ 20 V). At a peak current of about 4 kA, and with a pulse duration of 8 (micro)s, we observed mean ion charges states of about 6 for several cathode materials. In the case of platinum, the highest average charge state was 6.74 with ions of charge states as high as 10 present. For gold we found traces of charge state 11, with the highest average charge state of 7.25. At currents higher than 5 kA, non-metallic contaminations started to dominate the ion beam, preventing further enhancement of the metal charge states

  16. Development of Charge Sensitive Preamplifier and Readout Integrate Circuit Board for High Resolution Detector using ASIC Process

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, J. Y.; Kim, J. H.; Park, J. M.; Yang, J. Y.; Kim, K. Y.; Kim, Y. S. [RadTek Co., Daejeon (Korea, Republic of)

    2010-06-15

    - Design of discrete type charge sensitive amplifier for high resolution semi-conductor sensor - Design and develop the test board for the performance of charge sensitive amplifier with sensor - Performance of electrical test for the sensor and charge sensitive amplifier - Development of prototype 8 x 8 array type detector module - Noise equivalent charge test for the charge sensitive amplifier - Design and development of Micro SMD discrete type amplifier applying ASIC procedure - Development of Hybrid type charge sensitive amplifier including shape

  17. A novel chalcone-analogue as an optical sensor based on ground and excited states intramolecular charge transfer: A combined experimental and theoretical study

    International Nuclear Information System (INIS)

    Fayed, Tarek A.

    2006-01-01

    Steady-state absorption and emission spectroscopic techniques as well as semiempirical quantum calculations at the AM1 and ZINDO/S levels have been used to investigate the intramolecular charge transfer (ICT) behaviour of a novel chalcone namely; 1-(2-pyridyl)-5-(4-dimethylaminophenyl)-penta-2,4-diene-1-one, DMAC. The ground state DMAC has a significant ICT character and a great sensitivity to the hydrogen bond donating ability of the medium as reflected from the change of the absorption spectra in pure and mixed organic solvents. On the other hand, its excited singlet state exhibits high ICT characters as manifested by the drastic solvatochromic effects. These results are consistent with the data of charge density calculations in both the ground and excited state, which indicates enhancement of the charge transfer from the dimethyl-amino group to the carbonyl oxygen upon excitation. Also, the dipole moment calculations indicates a highly dipolar excited singlet state (Δμ eg = 15.5 D). The solvent dependence of the fluorescence quantum yield of DMAC was interpreted on the basis of positive and negative solvatokinetic as well as the hydrogen bonding effects. Incorporation of the 2-pyridyl group in the chemical structure of the present DMAC led to design of a potential optical sensor for probing acidity of the medium and metal cations such as Zn 2+ , Cd 2+ and Hg 2+ . This was concluded from the high acidochromic and metallochromic behaviour of DMAC on adding such cations to its acetonitrile solutions

  18. Production of Highly Charged Pharmaceutical Aerosols Using a New Aerosol Induction Charger.

    Science.gov (United States)

    Golshahi, Laleh; Longest, P Worth; Holbrook, Landon; Snead, Jessica; Hindle, Michael

    2015-09-01

    Properly charged particles can be used for effective lung targeting of pharmaceutical aerosols. The objective of this study was to characterize the performance of a new induction charger that operates with a mesh nebulizer for the production of highly charged submicrometer aerosols to bypass the mouth-throat and deliver clinically relevant doses of medications to the lungs. Variables of interest included combinations of model drug (albuterol sulfate) and charging excipient (NaCl) as well as strength of the charging field (1-5 kV/cm). Aerosol charge and size were measured using a modified electrical low pressure impactor system combined with high performance liquid chromatography. At the approximate mass median aerodynamic diameter (MMAD) of the aerosol (~0.4 μm), the induction charge on the particles was an order of magnitude above the field and diffusion charge limit. The nebulization rate was 439.3 ± 42.9 μl/min, which with a 0.1% w/v solution delivered 419.5 ± 34.2 μg of medication per minute. A new correlation was developed to predict particle charge produced by the induction charger. The combination of the aerosol induction charger and predictive correlations will allow for the practical generation and control of charged submicrometer aerosols for targeting deposition within the lungs.

  19. Amorphous silicon rich silicon nitride optical waveguides for high density integrated optics

    DEFF Research Database (Denmark)

    Philipp, Hugh T.; Andersen, Karin Nordström; Svendsen, Winnie Edith

    2004-01-01

    Amorphous silicon rich silicon nitride optical waveguides clad in silica are presented as a high-index contrast platform for high density integrated optics. Performance of different cross-sectional geometries have been measured and are presented with regards to bending loss and insertion loss...

  20. Charge transport in poly(p-phenylene vinylene) at low temperature and high electric field

    NARCIS (Netherlands)

    Katsouras, I.; Najafi, A.; Asadi, K.; Kronemeijer, A. J.; Oostra, A. J.; Koster, L. J. A.; de Leeuw, D. M.; Blom, P. W. M.

    Charge transport in poly(2-methoxy, 5-(2'-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV)-based hole-only diodes is investigated at high electric fields and low temperatures using a novel diode architecture. Charge carrier densities that are in the range of those in a field-effect transistor are

  1. Ion sources development at GANIL for radioactive beams and high charge state ions

    International Nuclear Information System (INIS)

    Leroy, R.; Barue, C.; Canet, C.; Dupuis, M.; Flambard, J.L.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Lecesne, N.; Leherissier, P.; Lemagnen, F.; Pacquet, J.Y.; Pellemoine-Landre, F.; Rataud, J.P.; Saint-Laurent, M.G.; Villari, A.C.C.; Maunoury, L.

    2001-01-01

    The GANIL laboratory has in charge the production of ion beams for nuclear and non nuclear physics. This article reviews the last developments that are underway in the fields of radioactive ion beam production, increase of the metallic ion intensities and production of highly charges ion beams. (authors)

  2. Solar photovoltaic charging of high voltage nickel metal hydride batteries using DC power conversion

    Science.gov (United States)

    Kelly, Nelson A.; Gibson, Thomas L.

    There are an increasing number of vehicle choices available that utilize batteries and electric motors to reduce tailpipe emissions and increase fuel economy. The eventual production of electricity and hydrogen in a renewable fashion, such as using solar energy, can achieve the long-term vision of having no tailpipe environmental impact, as well as eliminating the dependence of the transportation sector on dwindling supplies of petroleum for its energy. In this report we will demonstrate the solar-powered charging of the high-voltage nickel-metal hydride (NiMH) battery used in the GM 2-mode hybrid system. In previous studies we have used low-voltage solar modules to produce hydrogen via the electrolysis of water and to directly charge lithium-ion battery modules. Our strategy in the present work was to boost low-voltage PV voltage to over 300 V using DC-DC converters in order to charge the high-voltage NiMH battery, and to regulate the battery charging using software to program the electronic control unit supplied with the battery pack. A protocol for high-voltage battery charging was developed, and the solar to battery charging efficiency was measured under a variety of conditions. We believe this is the first time such high-voltage batteries have been charged using solar energy in order to prove the concept of efficient, solar-powered charging for battery-electric vehicles.

  3. High-frequency acoustic charge transport in GaAs nanowires

    NARCIS (Netherlands)

    Büyükköse, S.; Hernandez-Minguez, A.; Vratzov, B.; Somaschini, C.; Geelhaar, L.; Riechert, H.; van der Wiel, Wilfred Gerard; Santos, P.V.

    2014-01-01

    The oscillating piezoelectric fields accompanying surface acoustic waves are able to transport charge carriers in semiconductor heterostructures. Here, we demonstrate high-frequency (above 1 GHz) acoustic charge transport in GaAs-based nanowires deposited on a piezoelectric substrate. The short

  4. Fast optical signal processing in high bit rate OTDM systems

    DEFF Research Database (Denmark)

    Poulsen, Henrik Nørskov; Jepsen, Kim Stokholm; Clausen, Anders

    1998-01-01

    As all-optical signal processing is maturing, optical time division multiplexing (OTDM) has also gained interest for simple networking in high capacity backbone networks. As an example of a network scenario we show an OTDM bus interconnecting another OTDM bus, a single high capacity user...

  5. Highly confined ions store charge more efficiently in supercapacitors

    Science.gov (United States)

    Merlet, C.; Péan, C.; Rotenberg, B.; Madden, P. A.; Daffos, B.; Taberna, P.-L.; Simon, P.; Salanne, M.

    2013-10-01

    Liquids exhibit specific properties when they are adsorbed in nanoporous structures. This is particularly true in the context of supercapacitors, for which an anomalous increase in performance has been observed for nanoporous electrodes. This enhancement has been traditionally attributed in experimental studies to the effect of confinement of the ions from the electrolyte inside sub-nanometre pores, which is accompanied by their partial desolvation. Here we perform molecular dynamics simulations of realistic supercapacitors and show that this picture is correct at the microscopic scale. We provide a detailed analysis of the various environments experienced by the ions. We pick out four different adsorption types, and we, respectively, label them as edge, planar, hollow and pocket sites upon increase of the coordination of the molecular species by carbon atoms from the electrode. We show that both the desolvation and the local charge stored on the electrode increase with the degree of confinement.

  6. Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

    Energy Technology Data Exchange (ETDEWEB)

    Ligorio, G.; Nardi, M. V. [Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor Str. 6, 12489 Berlin (Germany); Steyrleuthner, R.; Neher, D. [Institute of Physics and Astronomy, Universität Potsdam, Karl-Liebknecht Str. 24, 14476 Potsdam (Germany); Ihiawakrim, D. [Institut de Physique et de Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, BP 43, 67034 Strasbourg, Cedex2 (France); Crespo-Monteiro, N.; Brinkmann, M. [Institut Charles Sadron CNRS, 23 rue du Loess, 67034 Strasbourg (France); Koch, N., E-mail: norbert.koch@physik.hu-berlin.de [Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor Str. 6, 12489 Berlin (Germany); Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Erneuerbare Energien, Albert-Einstein Str. 15, 12489 Berlin (Germany)

    2016-04-11

    We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 10{sup 4} due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contrast to the previous speculations, electrical bistability in such devices was not observed.

  7. Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

    International Nuclear Information System (INIS)

    Ligorio, G.; Nardi, M. V.; Steyrleuthner, R.; Neher, D.; Ihiawakrim, D.; Crespo-Monteiro, N.; Brinkmann, M.; Koch, N.

    2016-01-01

    We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 10 4 due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contrast to the previous speculations, electrical bistability in such devices was not observed.

  8. Metal nanoparticle mediated space charge and its optical control in an organic hole-only device

    OpenAIRE

    Ligorio, G.; Nardi, M. V.; Steyrleuthner, Robert; Ihiawakrim, D.; Crespo-Monteiro, N.; Brinkmann, M.; Neher, D.; Koch, N.

    2017-01-01

    We reveal the role of localized space charges in hole-only devices based on an organic semiconductor with embedded metal nanoparticles (MNPs). MNPs act as deep traps for holes and reduce the current density compared to a device without MNPs by a factor of 104 due to the build-up of localized space charge. Dynamic MNPs charged neutrality can be realized during operation by electron transfer from excitons created in the organic matrix, enabling light sensing independent of device bias. In contr...

  9. Experimental characterization of the Hitrap Cooler trap with highly charged ions.

    OpenAIRE

    Fedotova, Svetlana

    2013-01-01

    The HITRAP (Highly charged Ions TRAP)facility is being set up and commissioned at GSI, Darmstadt. It will provide heavy, highly charged ions at low velocities to high-precision atomic physics experiments. Within this work the Cooler trap- the key element of the HITRAP facility was tested. The Cooler trap was assembled, aligned, and commissioned in trapping experiments with ions from off-line sources.The work performed within the scope of this thesis provided the baseline for further operation...

  10. High-resolution X-ray spectra from low-temperature, highly charged ions

    International Nuclear Information System (INIS)

    Beiersdorfer, P.

    1996-09-01

    The electron beam ion traps (EBIT) at Livermore were designed for studying the x-ray emission of highly charged ions produced and excited by a monoenergetic electron beam. The precision with which the x-ray emission can be analyzed has recently been increased markedly when it became possible to decouple the temperature of the ions from the energy of the electron beam by several orders of magnitude. By adjusting the trap parameters, ion temperatures as low as 15.8±4.4 eV for Ti 20+ and 59.4±9.9 eV for Cs 45+ were achieved. These temperatures were more than two orders of magnitude lower than the energy of the multi-keV electron beam used for the production and excitation of the ions. A discussion of the techniques used to produce and study low-temperature highly charged ions is presented in this progress report. The low ion temperatures enabled measurements heretofore impossible. As an example, a direct observation of the natural line width of fast electric dipole allowed x-ray transitions is described. From the observed natural line width and b making use of the time-energy relations of the uncertainty principle we were able to determine a radiative transition rate of 1.65 fs for the 2p-3d resonance transition in neonlike Cs 45+ . A brief discussion of other high-precision measurements enabled by our new technique is also given

  11. On the nature of high field charge transport in reinforced silicone dielectrics: Experiment and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanhui, E-mail: huangy12@rpi.edu; Schadler, Linda S. [Department of Material Science and Engineering, Rensselaer Polytechnic Institute, 110 8th street, Troy, New York 12180 (United States)

    2016-08-07

    The high field charge injection and transport properties in reinforced silicone dielectrics were investigated by measuring the time-dependent space charge distribution and the current under dc conditions up to the breakdown field and were compared with the properties of other dielectric polymers. It is argued that the energy and spatial distribution of localized electronic states are crucial in determining these properties for polymer dielectrics. Tunneling to localized states likely dominates the charge injection process. A transient transport regime arises due to the relaxation of charge carriers into deep traps at the energy band tails and is successfully verified by a Monte Carlo simulation using the multiple-hopping model. The charge carrier mobility is found to be highly heterogeneous due to the non-uniform trapping. The slow moving electron packet exhibits a negative field dependent drift velocity possibly due to the spatial disorder of traps.

  12. A high charge state heavy ion beam source for heavy ion fusion

    International Nuclear Information System (INIS)

    Eylon, S.; Henestroza, E.

    1996-01-01

    A high current, low emittance, high charge state heavy ion beam source is being developed. This is designed to deliver a heavy ion fusion (HIF) driver accelerator scale beam. Using a high charge state beam in a driver accelerator for HIF may increase the acceleration efficiency, leading to a reduction in the driver accelerator size and cost. The proposed source system, which consists of a gas beam electron stripper followed by a high charge state beam separator, can be added to existing single charge state, low emittance, high brightness ion sources and injectors. We shall report on the source physics design using 3D beam simulations and experimental feasibility study results using a neutral gas stripper and a beam separator at the exit of the LBL 2 MV injector. (orig.)

  13. Theoretical studies of optics and charge transport in organic conducting oligomers and polymers: Rational design of improved transparent and conducting polymers

    Science.gov (United States)

    Hutchison, Geoffrey Rogers

    Theoretical studies on a variety of oligo- and polyheterocycles elucidate their optical and charge transport properties, suggesting new, improved transparent conductive polymers. First-principles calculations provide accurate methodologies for predicting both optical band gaps of neutral and cationic oligomers and intrinsic charge transfer rates. Multidimensional analysis reveals important motifs in chemical tailorability of oligoheterocycle optical and charge transport properties. The results suggest new directions for design of novel materials. Using both finite oligomer and infinite polymer calculations, the optical band gaps in polyheterocycles follow a modified particle-in-a-box formalism, scaling approximately as 1/N (where N is the number of monomer units) in short chains, saturating for long chains. Calculations demonstrate that band structure changes upon heteroatom substitution, (e.g., from polythiophene to polypyrrole) derive from heteroatom electron affinity. Further investigation of chemical variability in substituted oligoheterocycles using multidimensional statistics reveals the interplay between heteroatom and substituent in correlations between structure and redox/optical properties of neutral and cationic species. A linear correlation between band gaps of neutral and cationic species upon oxidation of conjugated oligomers, shows redshifts of optical absorption for most species and blueshifts for small band gap species. Interstrand charge-transport studies focus on two contributors to hopping-style charge transfer rates: internal reorganization energy and the electronic coupling matrix element. Statistical analysis of chemical variability of reorganization energies in oligoheterocycles proves the importance of reorganization energy in determining intrinsic charge transfer rates (e.g., charge mobility in unsubstituted oligothiophenes). Computed bandwidths across several oligothiophene crystal packing motifs show similar electron and hole bandwidths

  14. General mechanism involved in subwavelength optics of conducting microstructures: charge-oscillation-induced light emission and interference.

    Science.gov (United States)

    Huang, Xian-Rong; Peng, Ru-Wen

    2010-04-01

    Interactions between light and conducting microstructures or nanostructures can result in a variety of novel phenomena, but their underlying mechanisms have not been completely understood. From calculations of surface charge density waves on conducting gratings and by comparing them with classical surface plasmons, we revealed a general yet concrete picture regarding the coupling of light to free electron oscillation on structured conducting surfaces that can lead to oscillating subwavelength charge patterns (i.e., structured surface plasmons). New wavelets emitted from these light sources then destructively interfere to form evanescent waves. This principle, usually combined with other mechanisms, is mainly a geometrical effect that can be universally involved in light scattering from all periodic and non-periodic structures containing free electrons. This picture may provide clear guidelines for developing conductor-based nano-optical devices.

  15. Optical interconnect technologies for high-bandwidth ICT systems

    Science.gov (United States)

    Chujo, Norio; Takai, Toshiaki; Mizushima, Akiko; Arimoto, Hideo; Matsuoka, Yasunobu; Yamashita, Hiroki; Matsushima, Naoki

    2016-03-01

    The bandwidth of information and communication technology (ICT) systems is increasing and is predicted to reach more than 10 Tb/s. However, an electrical interconnect cannot achieve such bandwidth because of its density limits. To solve this problem, we propose two types of high-density optical fiber wiring for backplanes and circuit boards such as interface boards and switch boards. One type uses routed ribbon fiber in a circuit board because it has the ability to be formed into complex shapes to avoid interfering with the LSI and electrical components on the board. The backplane is required to exhibit high density and flexibility, so the second type uses loose fiber. We developed a 9.6-Tb/s optical interconnect demonstration system using embedded optical modules, optical backplane, and optical connector in a network apparatus chassis. We achieved 25-Gb/s transmission between FPGAs via the optical backplane.

  16. A high-performance channel engineered charge-plasma-based MOSFET with high-κ spacer

    Science.gov (United States)

    Shan, Chan; Wang, Ying; Luo, Xin; Bao, Meng-tian; Yu, Cheng-hao; Cao, Fei

    2017-12-01

    In this paper, the performance of graded channel double-gate MOSFET (GC-DGFET) that utilizes the charge-plasma concept and a high-κ spacer is investigated through 2-D device simulations. The results demonstrate that GC-DGFET with high-κ spacer can effectively improve the ON-state driving current (ION) and reduce the OFF-leakage current (IOFF). We find that reduction of the initial energy barrier between the source and channel is the origin of this ION enhancement. The reason for the IOFF reduction is identified to be the extension of the effective channel length owing to the fringing field via high-κ spacers. Consequently, these devices offer enhanced performance by reducing the total gate-to-gate capacitance (Cgg) and decreasing the intrinsic delay (τ).

  17. High-resolution retinal imaging using adaptive optics and Fourier-domain optical coherence tomography

    Science.gov (United States)

    Olivier, Scot S.; Werner, John S.; Zawadzki, Robert J.; Laut, Sophie P.; Jones, Steven M.

    2010-09-07

    This invention permits retinal images to be acquired at high speed and with unprecedented resolution in three dimensions (4.times.4.times.6 .mu.m). The instrument achieves high lateral resolution by using adaptive optics to correct optical aberrations of the human eye in real time. High axial resolution and high speed are made possible by the use of Fourier-domain optical coherence tomography. Using this system, we have demonstrated the ability to image microscopic blood vessels and the cone photoreceptor mosaic.

  18. Simulations of Beam Optics and Bremsstrahlung for High Intensity and Brightness Channeling Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, J. [Sokendai, Tsukuba; Piot, P. [NIU, DeKalb; Sen, T. [Fermilab

    2018-04-12

    This paper presents X-ray spectra of channeling radiation expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations for a range of bunch charges. We estimate the X-ray spectra including bremsstrahlung background. We discuss how the electron beam distributions after the diamond crystal are affected by channeling. We discuss an X-ray detector system to avoid pile-up effects during high charge operations.

  19. HIAF: New opportunities for atomic physics with highly charged heavy ions

    Science.gov (United States)

    Ma, X.; Wen, W. Q.; Zhang, S. F.; Yu, D. Y.; Cheng, R.; Yang, J.; Huang, Z. K.; Wang, H. B.; Zhu, X. L.; Cai, X.; Zhao, Y. T.; Mao, L. J.; Yang, J. C.; Zhou, X. H.; Xu, H. S.; Yuan, Y. J.; Xia, J. W.; Zhao, H. W.; Xiao, G. Q.; Zhan, W. L.

    2017-10-01

    A new project, High Intensity heavy ion Accelerator Facility (HIAF), is currently being under design and construction in China. HIAF will provide beams of stable and unstable heavy ions with high energies, high intensities and high quality. An overview of new opportunities for atomic physics using highly charged ions and radioactive heavy ions at HIAF is given.

  20. High energy laser optics manufacturing: a preliminary study

    International Nuclear Information System (INIS)

    Baird, E.D.

    1980-07-01

    This report presents concepts and methods, major conclusions, and major recommendations concerning the fabrication of high energy laser optics (HELO) that are to be machined by the Large Optics Diamond Turning Machine (LODTM) at the Lawrence Livermore National Laboratory (LLNL). Detailed discussions of concepts and methods proposed for metrological operations, polishing of reflective surfaces, mounting of optical components, construction of mirror substrates, and applications of coatings are included

  1. High Temperature Thermosetting Polyimide Nanocomposites Prepared with Reduced Charge Organoclay

    Science.gov (United States)

    Campbell, Sandi; Liang, Margaret I.

    2005-01-01

    The naturally occurring sodium and calcium cations found in bentonite clay galleries were exchanged with lithium cations. Following the cation exchange, a series of reduced charge clays were prepared by heat treatment of the lithium bentonite at 130 C, 150 C, or 170 C. Inductively coupled plasma (ICP) analysis showed that heating the lithium clay at elevated temperatures reduced its cation exchange capacity. Ion exchange of heat-treated clays with either a protonated alkyl amine or a protonated aromatic diamine resulted in decreasing amounts of the organic modifier incorporated into the lithium clay. The level of silicate dispersion in a thermosetting polyimide matrix was dependent upon the temperature of Li-clay heat treatment as well as the organic modification. In general, clays treated at 150 C or 170 C, and exchanged with protonated octadcylamine or protonated 2,2'-dimethlybenzidine (DMBZ) showed a higher degree of dispersion than clays treated at 130 C, or exchanged with protonated dodecylamine. Dynamic mechanical analysis showed little change in the storage modulus or T(sub g) of the nanocomposites compared to the base resin. However, long term isothermal aging of the samples showed a significant decrease in the resin oxidative weight loss. Nanocomposite samples aged in air for 1000 hours at 288 C showed of to a decrease in weight loss compared to that of the base resin. This again was dependent on the temperature at which the Li-clay was heated and the choice of organic modification.

  2. High sensitivity optical measurement of skin gloss

    NARCIS (Netherlands)

    Ezerskaia, A.; Ras, Arno; Bloemen, Pascal; Pereira, S.F.; Urbach, Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between

  3. Floquet Engineering of Optical Solenoids and Quantized Charge Pumping along Tailored Paths in Two-Dimensional Chern Insulators

    Science.gov (United States)

    Wang, Botao; Ünal, F. Nur; Eckardt, André

    2018-06-01

    The insertion of a local magnetic flux, as the one created by a thin solenoid, plays an important role in gedanken experiments of quantum Hall physics. By combining Floquet engineering of artificial magnetic fields with the ability of single-site addressing in quantum gas microscopes, we propose a scheme for the realization of such local solenoid-type magnetic fields in optical lattices. We show that it can be employed to manipulate and probe elementary excitations of a topological Chern insulator. This includes quantized adiabatic charge pumping along tailored paths inside the bulk, as well as the controlled population of edge modes.

  4. Characterization and control of wafer charging effects during high-current ion implantation

    International Nuclear Information System (INIS)

    Current, M.I.; Lukaszek, W.; Dixon, W.; Vella, M.C.; Messick, C.; Shideler, J.; Reno, S.

    1994-02-01

    EEPROM-based sense and memory devices provide direct measures of the charge flow and potentials occurring on the surface of wafers during ion beam processing. Sensor design and applications for high current ion implantation are discussed

  5. A new method of removing the high value feedback resistor in the charge sensitive preamplifier

    International Nuclear Information System (INIS)

    Xi Deming

    1993-01-01

    A new method of removing the high value feedback resistor in the charge sensitive preamplifier is introduced. The circuit analysis of this novel design is described and the measured performances of a practical circuit are provided

  6. The importance of charge-transfer interactions in determining chromophoric dissolved organic matter (CDOM) optical and photochemical properties.

    Science.gov (United States)

    Sharpless, Charles M; Blough, Neil V

    2014-04-01

    Absorption of sunlight by chromophoric dissolved natural organic matter (CDOM) is environmentally significant because it controls photic zone depth and causes photochemistry that affects elemental cycling and contaminant fate. Both the optics (absorbance and fluorescence) and photochemistry of CDOM display unusual properties that cannot easily be ascribed to a superposition of individual chromophores. These include (i) broad, unstructured absorbance that decreases monotonically well into the visible and near IR, (ii) fluorescence emission spectra that all fall into a single envelope regardless of the excitation wavelength, and (iii) photobleaching and photochemical quantum yields that decrease monotonically with increasing wavelength. In contrast to a simple superposition model, these phenomena and others can be reasonably well explained by a physical model in which charge-transfer interactions between electron donating and accepting chromophores within the CDOM control the optical and photophysical properties. This review summarizes current understanding of the processes underlying CDOM photophysics and photochemistry as well as their physical basis.

  7. A Large Aperture, High Energy Laser System for Optics and Optical Component Testing

    International Nuclear Information System (INIS)

    Nostrand, M.C.; Weiland, T.L.; Luthi, R.L.; Vickers, J.L.; Sell, W.D.; Stanley, J.A.; Honig, J.; Auerbach, J.; Hackel, R.P.; Wegner, P.J.

    2003-01-01

    A large aperture, kJ-class, multi-wavelength Nd-glass laser system has been constructed at Lawrence Livermore National Lab which has unique capabilities for studying a wide variety of optical phenomena. The master-oscillator, power-amplifier (MOPA) configuration of this ''Optical Sciences Laser'' (OSL) produces 1053 nm radiation with shaped pulse lengths which are variable from 0.1-100 ns. The output can be frequency doubled or tripled with high conversion efficiency with a resultant 100 cm 2 high quality output beam. This facility can accommodate prototype hardware for large-scale inertial confinement fusion lasers allowing for investigation of integrated system issues such as optical lifetime at high fluence, optics contamination, compatibility of non-optical materials, and laser diagnostics

  8. Atomic physics of highly charged ions in an electron beam ion trap

    International Nuclear Information System (INIS)

    Marrs, R.E.

    1990-07-01

    Two electron beam ion traps are in use at LLNL for the purpose of studying the properties of very highly charged ions and their interactions with electrons. This paper reviews the operation of the traps and discusses recent experiments in three areas: precision transition energy measurements in the limit of very high ion charge, dielectronic recombination measurements for the He-like isoelectronic sequence, and measurements of x-ray polarization. 22 refs., 11 figs., 1 tab

  9. Acceleration of high charge density electron beams in the SLAC linac

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Clendenin, J.E.; Jobe, R.K.; Lueth, V.G.; Millich, A.; Ross, M.C.; Seeman, J.T.; Stiening, R.F.

    1984-01-01

    The SLAC Linear Collider (SLC) will require both electron and positron beams of very high charge density and low emittance to be accelerated to about 50 GeV in the SLAC 3-km linac. The linac is in the process of being improved to meet this requirement. The program to accelerate an electron beam of high charge density through the first third of the SLC linac is described and the experimental results are discussed. 7 references, 5 figures

  10. The effect of temperature on guiding of slow highly charged ions through a mesoscopic glass capillary

    International Nuclear Information System (INIS)

    Bereczky, R J; Tökési, K; Kowarik, G; Ladinig, F; Schrempf, D; Aumayr, F

    2012-01-01

    We present first temperature dependent transmission measurements of slow highly charged ions through a single, straight Duran glass capillary with a high aspect ratio. By changing the temperature of the glass capillary the electrical conductivity of the Duran can be varied by several orders of magnitude. This held the promise to investigate the effect of conductivity on particle transport (build-up and removal of charge patches) through capillaries in more details.

  11. Charged particle tracking in high multiplicity events at RHIC

    International Nuclear Information System (INIS)

    Foley, K.J.; Love, W.A.

    1985-01-01

    It is generally accepted that the ability to track some fraction of the charged particles produced in heavy ion collisions is very desirable. At a very minimum, one must detect the occurance of multiple interactions in a single crossing. The very tight beam structure at RHIC does not favor time separation, so the location of separate vertices seems the best solution. The limits of tracking large numbers of tracks in a solid angle approaching 4π have been explored. A model detector considered is a 2.5 m radius TPC, a true 3D tracking device. In order to estimate the particle density of a function of production angle, five Hijet Au-Au central events were used to deduce the particle density distribution as a function of polar angle. An important feature of a tracking detector is the effective ''pixel'' size - the area within which two tracks cannot be resolved. In a TPC with multistep avalanche chamber readout this is approximately 3 mm x 3 mm or approx.0.1 cm 2 . Using this pixel size we have calculated the radius at which the number of particles/pixel is 0.01 and 0.1. With the exception of the region very near the beam expect these distributions aren't expected to change very much with the application of a low (approx. 0.5 tesla) magnetic field. While the actual reconstruction efficiency will depend on the fine details of the apparatus and reconstruction program, the 1% fill fraction is safe for efficiencies in the 80 to 90% region. Tracking is found to be feasible at pseudorapidities up to 3

  12. Innovative on board payload optical architecture for high throughput satellites

    Science.gov (United States)

    Baudet, D.; Braux, B.; Prieur, O.; Hughes, R.; Wilkinson, M.; Latunde-Dada, K.; Jahns, J.; Lohmann, U.; Fey, D.; Karafolas, N.

    2017-11-01

    For the next generation of HighThroughPut (HTP) Telecommunications Satellites, space end users' needs will result in higher link speeds and an increase in the number of channels; up to 512 channels running at 10Gbits/s. By keeping electrical interconnections based on copper, the constraints in term of power dissipation, number of electrical wires and signal integrity will become too demanding. The replacement of the electrical links by optical links is the most adapted solution as it provides high speed links with low power consumption and no EMC/EMI. But replacing all electrical links by optical links of an On Board Payload (OBP) is challenging. It is not simply a matter of replacing electrical components with optical but rather the whole concept and architecture have to be rethought to achieve a high reliability and high performance optical solution. In this context, this paper will present the concept of an Innovative OBP Optical Architecture. The optical architecture was defined to meet the critical requirements of the application: signal speed, number of channels, space reliability, power dissipation, optical signals crossing and components availability. The resulting architecture is challenging and the need for new developments is highlighted. But this innovative optically interconnected architecture will substantially outperform standard electrical ones.

  13. ACADEMIC TRAINING: Probing nature with high precision; particle traps, laser spectroscopy and optical combs

    CERN Multimedia

    Françoise Benz

    2002-01-01

    17, 18, 19 June LECTURE SERIES from 11.00 to 12.00 hrs - Auditorium, bldg. 500 Probing nature with high precision; particle traps, laser spectroscopy and optical combs by G. GABRIELSE / Harvard University, USA Experiments with atomic energy scales probe nature and its symmetries with exquisite precision. Particle traps allow the manipulation of single charged particles for months at a time, allow the most accurate comparison of theory and experiment, and promise to allow better measurement of fundamental quantities like the fine structure constant. Ions and atoms can be probed with lasers that are phase locked to microwave frequency standards via optical combs, thus calibrating optical sources in terms of the official cesium second. A series of three lectures will illustrate what can be measured and discuss key techniques.  ACADEMIC TRAINING Françoise Benz Tel. 73127 francoise.benz@cern.ch

  14. Ion temperatures in HIP-1 and SUMMA from charge-exchange neutral optical emission spectra

    Science.gov (United States)

    Patch, R. W.; Lauver, M. R.

    1976-01-01

    Ion temperatures were obtained from observations of the H sub alpha, D sub alpha, and He 587.6 nm lines emitted from hydrogen, deuterium, and helium plasmas in the SUMMA and HIP-1 mirror devices at Lewis Research Center. Steady state discharges were formed by applying a radially inward dc electric field between cylindrical or annular anodes and hollow cathodes located at the peaks of the mirrors. The ion temperatures were found from the Doppler broadening of the charge-exchange components of spectral lines. A statistical method was developed for obtaining scaling relations of ion temperature as a function of current, voltage, and magnetic flux density. Derivations are given that take into account triangular monochromator slit functions, loss cones, and superimposed charge-exchange processes. In addition, the Doppler broadening was found to be sensitive to the influence of drift on charge-exchange cross section. The effects of finite ion-cyclotron radius, cascading, and delayed emission are reviewed.

  15. High sensitivity optical measurement of skin gloss

    OpenAIRE

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F.; Urbach, H. Paul; Varghese, Babu

    2017-01-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the...

  16. Charge-state correlated cross sections for the production of low-velocity highly charged Ne ions by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Gray, T.J.; Cocke, C.L.; Justiniano, E.

    1980-01-01

    We report measured cross sections for the collisional production of highly charged low-velocity Ne recoil ions resulting from the bombardment of a thin Ne gas target by highly charged 1-MeV/amu C, N, O, and F projectiles. The measurements were made using time-of-flight techniques which allowed the simultaneous identification of the final charge state of both the low-velocity recoil ion and the high-velocity projectile for each collision event. For a given incident-projectile charge state, the recoil charge-state distribution is very dependent upon the final charge state of the projectile. Single- and double-electron capture events by incident bare nuclei and projectile K-shell ionization during the collision cause large shifts in the recoil charge-state distributions toward higher charge states. A previously proposed energy-deposition model is modified to include the effects of projectile charge-changing collisions during the collision for bare and hydrogenlike projectiles and is used to discuss the present experimental results

  17. Optical signal processing techniques and applications of optical phase modulation in high-speed communication systems

    Science.gov (United States)

    Deng, Ning

    In recent years, optical phase modulation has attracted much research attention in the field of fiber optic communications. Compared with the traditional optical intensity-modulated signal, one of the main merits of the optical phase-modulated signal is the better transmission performance. For optical phase modulation, in spite of the comprehensive study of its transmission performance, only a little research has been carried out in terms of its functions, applications and signal processing for future optical networks. These issues are systematically investigated in this thesis. The research findings suggest that optical phase modulation and its signal processing can greatly facilitate flexible network functions and high bandwidth which can be enjoyed by end users. In the thesis, the most important physical-layer technology, signal processing and multiplexing, are investigated with optical phase-modulated signals. Novel and advantageous signal processing and multiplexing approaches are proposed and studied. Experimental investigations are also reported and discussed in the thesis. Optical time-division multiplexing and demultiplexing. With the ever-increasing demand on communication bandwidth, optical time division multiplexing (OTDM) is an effective approach to upgrade the capacity of each wavelength channel in current optical systems. OTDM multiplexing can be simply realized, however, the demultiplexing requires relatively complicated signal processing and stringent timing control, and thus hinders its practicability. To tackle this problem, in this thesis a new OTDM scheme with hybrid DPSK and OOK signals is proposed. Experimental investigation shows this scheme can greatly enhance the demultiplexing timing misalignment and improve the demultiplexing performance, and thus make OTDM more practical and cost effective. All-optical signal processing. In current and future optical communication systems and networks, the data rate per wavelength has been approaching

  18. High-speed charge-to-time converter ASIC for the Super-Kamiokande detector

    Energy Technology Data Exchange (ETDEWEB)

    Nishino, H., E-mail: nishino@post.kek.j [Institute for Cosmic Ray Research, University of Tokyo, Chiba 277-8582 (Japan); Awai, K.; Hayato, Y.; Nakayama, S.; Okumura, K.; Shiozawa, M.; Takeda, A. [Institute for Cosmic Ray Research, University of Tokyo, Chiba 277-8582 (Japan); Ishikawa, K.; Minegishi, A. [Iwatsu Test Instruments Corporation, Tokyo 168-8511 (Japan); Arai, Y. [The Institute of Particle and Nuclear Studies, KEK, Ibaraki 305-0801 (Japan)

    2009-11-11

    A new application-specific integrated circuit (ASIC), the high-speed charge-to-time converter (QTC) IWATSU CLC101, provides three channels, each consisting of preamplifier, discriminator, low-pass filter, and charge integration circuitry, optimized for the waveform of a photomultiplier tube (PMT). This ASIC detects PMT signals using individual built-in discriminators and drives output timing signals whose width represents the integrated charge of the PMT signal. Combined with external input circuits composed of passive elements, the QTC provides full analog signal processing for the detector's PMTs, ready for further processing by time-to-digital converters (TDCs). High-rate (>1MHz) signal processing is achieved by short-charge-conversion-time and baseline-restoration circuits. Wide-range charge measurements are enabled by offering three gain ranges while maintaining a short cycle time. QTC chip test results show good analog performance, with efficient detection for a single photoelectron signal, four orders of magnitude dynamic range (0.3mVapprox3V; 0.2approx2500pC), 1% charge linearity, 0.2 pC charge resolution, and 0.1 ns timing resolution. Test results on ambient temperature dependence, channel isolation, and rate dependence also meet specifications.

  19. High-speed charge-to-time converter ASIC for the Super-Kamiokande detector

    International Nuclear Information System (INIS)

    Nishino, H.; Awai, K.; Hayato, Y.; Nakayama, S.; Okumura, K.; Shiozawa, M.; Takeda, A.; Ishikawa, K.; Minegishi, A.; Arai, Y.

    2009-01-01

    A new application-specific integrated circuit (ASIC), the high-speed charge-to-time converter (QTC) IWATSU CLC101, provides three channels, each consisting of preamplifier, discriminator, low-pass filter, and charge integration circuitry, optimized for the waveform of a photomultiplier tube (PMT). This ASIC detects PMT signals using individual built-in discriminators and drives output timing signals whose width represents the integrated charge of the PMT signal. Combined with external input circuits composed of passive elements, the QTC provides full analog signal processing for the detector's PMTs, ready for further processing by time-to-digital converters (TDCs). High-rate (>1MHz) signal processing is achieved by short-charge-conversion-time and baseline-restoration circuits. Wide-range charge measurements are enabled by offering three gain ranges while maintaining a short cycle time. QTC chip test results show good analog performance, with efficient detection for a single photoelectron signal, four orders of magnitude dynamic range (0.3mV∼3V; 0.2∼2500pC), 1% charge linearity, 0.2 pC charge resolution, and 0.1 ns timing resolution. Test results on ambient temperature dependence, channel isolation, and rate dependence also meet specifications.

  20. Novel simulation method of space charge effects in electron optical systems including emission of electrons

    Czech Academy of Sciences Publication Activity Database

    Zelinka, Jiří; Oral, Martin; Radlička, Tomáš

    2018-01-01

    Roč. 184, JAN (2018), s. 66-76 ISSN 0304-3991 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : space charge * self-consistent simulation * aberration polynomial * electron emission Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.843, year: 2016

  1. Transient optical studies of charge recombination dynamics in a polymer/fullerene composite at room temperature

    NARCIS (Netherlands)

    Montanari, Ivan; Nogueira, Ana F.; Nelson, Jenny; Durrant, James R.; Winder, Christoph; Loi, Maria Antonietta; Sariciftci, Niyazi Serdar; Brabec, Christoph

    2002-01-01

    The recombination kinetics of photogenerated charge carriers in a composite of poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1-4-phenylene vinylene], (MDMO–PPV) and the functionalised fullerene 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 are investigated at room temperature by transient absorption

  2. Overview on collision processes of highly charged ions with atoms present status and problems

    International Nuclear Information System (INIS)

    Janev, R.K.

    1983-05-01

    This paper provides a brief discussion on the present status of the collision physics of highly charged ions with atoms. The emphasis is on the main achievements in understanding and describing the most important collision processes, and as charge transfer, ionization and Auger-type processes, and even more on those open problems which, due either to their scientific or practical importance, represent challenges to current research in this field. The paper concentrates on general ideas and problems whose development and solutions have advanced or will advance our basic understanding of the collision dynamics of multiply charged ions with atoms

  3. Charge Carrier Dynamics and pH Effect on Optical Properties of Anionic and Cationic Porphyrin-Graphene Oxide Composites

    Science.gov (United States)

    Bajjou, O.; Bakour, A.; Khenfouch, M.; Baitoul, M.; Mothudi, B.; Maaza, M.; Faulques, E.

    2018-02-01

    Composites of graphene oxide (GO) functionalized with Sn(V) tetrakis (4-pyridyl)porphyrin (SnTPyP2+) and meso-tetrakis(4-phenylsulfonic acid)porphyrin (H4TPPS4 2- ) were prepared at different pH values.Successful synthesis of water-soluble stable suspension of GO-SnTPyP2+ and GO-H4TPPS4 2-was confirmed using various spectroscopic techniques, including scanning electronic microscopy (SEM), Raman spectroscopy, and ultraviolet-visible (UV-Vis) absorption. Variation of the pH was found to strongly influence the optical properties of the GO-SnTPyP2+ and GO-H4TPPS4 2-composites, as demonstrated by the UV-Vis absorption results. Steady-state photoluminescence (PL) and time-resolved PL (TRPL) results for both composites showed PL quenching and decrease in the exciton mean lifetime, suggesting strong excited-state interactions between the different components. Moreover, charge carrier dynamics study revealed that insertion of GO into both porphyrin derivatives led to faster mean lifetime for excitons with a slight advantage in the case of the cationic porphyrin-GO composite, making it a better choice for charge separation applications thanks to the higher efficiency of charge/energy transfer interactions.

  4. High speed all-optical networks

    Science.gov (United States)

    Chlamtac, Imrich

    1993-01-01

    An inherent problem of conventional point-to-point WAN architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. This report presents the first solution to WDM based WAN networks that overcomes this limitation. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs.

  5. Charge exchange processes of high energy heavy ions channeled in crystals

    International Nuclear Information System (INIS)

    Andriamonje, S.; Dural, J.; Toulemonde, M.; Groeneveld, K.O.; Maier, R.; Quere, Y.

    1990-01-01

    The interaction of moving ions with single crystals is very sensitive to the orientation of the incident beam with respect to the crystalline directions of the target. The experiments show that high energy heavy ion channeling deeply modifies the slowing down and charge exchange processes. In this review, we describe the opportunity offered by channeling conditions to study the charge exchange processes. Some aspects of the charge exchange processes with high energy channeled heavy ions are selected from the extensive literature published over the past few years on this subject. Special attention is given to the work performed at the GANIL facility on the study of Radiative Electron Capture (REG), Electron Impact Ionisation (EII), and convoy electron emission. Finally we emphasize the interest of studying resonant charge exchange processes such as Resonant Coherent Excitation (RCE), Resonant Transfer and Excitation (RTE) or Dielectronic Recombination (DR) and the recently proposed Nuclear Excitation by Electron Capture (NEEC)

  6. Benchmark of Space Charge Simulations and Comparison with Experimental Results for High Intensity, Low Energy Accelerators

    CERN Document Server

    Cousineau, Sarah M

    2005-01-01

    Space charge effects are a major contributor to beam halo and emittance growth leading to beam loss in high intensity, low energy accelerators. As future accelerators strive towards unprecedented levels of beam intensity and beam loss control, a more comprehensive understanding of space charge effects is required. A wealth of simulation tools have been developed for modeling beams in linacs and rings, and with the growing availability of high-speed computing systems, computationally expensive problems that were inconceivable a decade ago are now being handled with relative ease. This has opened the field for realistic simulations of space charge effects, including detailed benchmarks with experimental data. A great deal of effort is being focused in this direction, and several recent benchmark studies have produced remarkably successful results. This paper reviews the achievements in space charge benchmarking in the last few years, and discusses the challenges that remain.

  7. New Architecture of Optical Interconnect for High-Speed Optical Computerized Data Networks (Nonlinear Response

    Directory of Open Access Journals (Sweden)

    El-Sayed A. El-Badawy

    2008-02-01

    Full Text Available Although research into the use of optics in computers has increased in the last and current decades, the fact remains that electronics is still superior to optics in almost every way. Research into the use of optics at this stage mirrors the research into electronics after the 2nd World War. The advantages of using fiber optics over wiring are the same as the argument for using optics over electronics in computers. Even through totally optical computers are now a reality, computers that combine both electronics and optics, electro-optic hybrids, have been in use for some time. In the present paper, architecture of optical interconnect is built up on the bases of four Vertical-Cavity Surface- Emitting Laser Diodes (VCSELD and two optical links where thermal effects of both the diodes and the links are included. Nonlinear relations are correlated to investigate the power-current and the voltage-current dependences of the four devices. The good performance (high speed of the interconnect is deeply and parametrically investigated under wide ranges of the affecting parameters. The high speed performance is processed through three different effects, namely the device 3-dB bandwidth, the link dispersion characteristics, and the transmitted bit rate (soliton. Eight combinations are investigated; each possesses its own characteristics. The best architecture is the one composed of VCSELD that operates at 850 nm and the silica fiber whatever the operating set of causes. This combination possesses the largest device 3-dB bandwidth, the largest link bandwidth and the largest soliton transmitted bit rate. The increase of the ambient temperature reduces the high-speed performance of the interconnect

  8. High sensitivity optical measurement of skin gloss.

    Science.gov (United States)

    Ezerskaia, Anna; Ras, Arno; Bloemen, Pascal; Pereira, Silvania F; Urbach, H Paul; Varghese, Babu

    2017-09-01

    We demonstrate a low-cost optical method for measuring the gloss properties with improved sensitivity in the low gloss regime, relevant for skin gloss properties. The gloss estimation method is based on, on the one hand, the slope of the intensity gradient in the transition regime between specular and diffuse reflection and on the other on the sum over the intensities of pixels above threshold, derived from a camera image obtained using unpolarized white light illumination. We demonstrate the improved sensitivity of the two proposed methods using Monte Carlo simulations and experiments performed on ISO gloss calibration standards with an optical prototype. The performance and linearity of the method was compared with different professional gloss measurement devices based on the ratio of specular to diffuse intensity. We demonstrate the feasibility for in-vivo skin gloss measurements by quantifying the temporal evolution of skin gloss after application of standard paraffin cream bases on skin. The presented method opens new possibilities in the fields of cosmetology and dermatopharmacology for measuring the skin gloss and resorption kinetics and the pharmacodynamics of various external agents.

  9. An inexpensive high-temperature optical fiber thermometer

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Allred, David D.

    2017-01-01

    An optical fiber thermometer consists of an optical fiber whose tip is coated with a highly conductive, opaque material. When heated, this sensing tip becomes an isothermal cavity that emits like a blackbody. This emission is used to predict the sensing tip temperature. In this work, analytical and experimental research has been conducted to further advance the development of optical fiber thermometry. An inexpensive optical fiber thermometer is developed by applying a thin coating of a high-temperature cement onto the tip of a silica optical fiber. An FTIR spectrometer is used to detect the spectral radiance exiting the fiber. A rigorous mathematical model of the irradiation incident on the detection system is developed. The optical fiber thermometer is calibrated using a blackbody radiator and inverse methods are used to predict the sensing tip temperature when exposed to various heat sources. - Highlights: • An inexpensive coating for an optical fiber thermometer sensing tip is tested. • Inverse heat transfer methods are used to estimate the sensing tip temperature. • An FTIR spectrometer is used as the detector to test the optical fiber thermometer using various heat sources.

  10. Moment-Preserving Computational Approach for High Energy Charged Particle Transport

    Science.gov (United States)

    2016-05-16

    posed, but with modified cross sections such that the resulting single-event Monte Carlo simulation is computationally efficient (minutes vs . days...configurations, which are all characteristics of real world applications. In other words , it is possible to simulate real, physical phenomena using charged...0 < 0.95) ~ 1 2() ≫ 1, (3) Demonstrating that scattering is highly forward peaked. Thus, the picture of charged particle interactions

  11. Search for Fractionally Charged Nuclei in High-Energy Oxygen-Lead Collisions

    CERN Multimedia

    2002-01-01

    We propose to use stacks of CR-39 plastic track detectors to look for fractionally charged projectile fragments produced in collisions of high-energy oxygen, sulfur, and calcium nuclei with a lead target. The expected charge resolution is @s^z~=~0.06e for fragments with 17e/3~@$<$~Z~@$<$~23e/3. We request that two target + stack assemblies be exposed to 1~x~10|5 oxygen nuclei at maximum available energy.

  12. Gain reduction due to space charge at high counting rates in multiwire proportional chambers

    International Nuclear Information System (INIS)

    Smith, G.C.; Mathieson, E.

    1986-10-01

    Measurements with a small MWPC of gas gain reduction, due to ion space charge at high counting rates, have been compared with theoretical predictions. The quantity ln(q/q 0 )/(q/q 0 ), where (q/q 0 ) is the relative reduced avalanche charge, has been found to be closely proportional to count rate, as predicted. The constant of proportionality is in good agreement with calculations made with a modified version of the original, simplified theory

  13. Evaporative cooling of highly charged ions in EBIT [Electron Beam Ion Trap]: An experimental realization

    International Nuclear Information System (INIS)

    Schneider, M.B.; Levine, M.A.; Bennett, C.L.; Henderson, J.R.; Knapp, D.A.; Marrs, R.E.

    1988-01-01

    Both the total number and trapping lifetime of near-neon-like gold ions held in an electron beam ion trap have been greatly increased by a process of 'evaporative cooling'. A continuous flow of low-charge-state ions into the trap cools the high-charge-state ions in the trap. Preliminary experimental results using titanium ions as a coolant are presented. 8 refs., 6 figs., 2 tabs

  14. High-temperature polyimide coating for optical fibres

    Energy Technology Data Exchange (ETDEWEB)

    Semjonov, S L; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Sapozhnikov, D A; Erin, D Yu; Zabegaeva, O N; Kushtavkina, I A; Vygodskii, Ya S [A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow (Russian Federation); Nishchev, K N [N.P. Ogarev Mordovia State University, Saransk (Russian Federation)

    2015-04-30

    We present our first results on the fabrication of new, high-performance polyimide coatings. The key components of the coatings are polyimides containing various cardo and/or fluoroalkylene groups, which allows the coatings to retain their high-temperature stability and facilitates the storage of the starting polymer and the optical fibre coating process owing to the good solubility of such copolymers in many organic solvents. Annealing for 30 s, 1 h and 24 h at temperatures of 430, 350 and 300 °C, respectively, reduces the strength of optical fibres having such coating by no more than 10%. (optical fibres)

  15. Magneto-optical system for high speed real time imaging

    Science.gov (United States)

    Baziljevich, M.; Barness, D.; Sinvani, M.; Perel, E.; Shaulov, A.; Yeshurun, Y.

    2012-08-01

    A new magneto-optical system has been developed to expand the range of high speed real time magneto-optical imaging. A special source for the external magnetic field has also been designed, using a pump solenoid to rapidly excite the field coil. Together with careful modifications of the cryostat, to reduce eddy currents, ramping rates reaching 3000 T/s have been achieved. Using a powerful laser as the light source, a custom designed optical assembly, and a high speed digital camera, real time imaging rates up to 30 000 frames per seconds have been demonstrated.

  16. Charge fluctuations in high-electron-mobility transistors: a review

    International Nuclear Information System (INIS)

    Green, F.

    1993-01-01

    The quasi-two-dimensional carrier population, free to move within a near-perfect crystalline matrix, is the key to remarkable improvements in signal gain, current density and quiet operation. Current-fluctuation effects are central to all of these properties. Some of these are easily understood within linear-response theory, but other fluctuation phenomena are less tractable. In particular, nonequilibrium noise poses significant theoretical challenges, both descriptive and predictive. This paper examines a few of the basic physical issues which motivate device-noise theory. The structure and operation of high-electron-mobility transistor are first reviewed. The recent nonlinear fluctuation theory of Stanton and Wilkins (1987) help to identify at least some of the complicated noise physics which can arise when carriers in GaAs-like conduction bands are subjected to high fields. Simple examples of fluctuation-dominated behaviour are discussed, with numerical illustrations. 20 refs., 9 figs

  17. Application of Beyond Bound Decoding for High Speed Optical Communications

    DEFF Research Database (Denmark)

    Li, Bomin; Larsen, Knud J.; Vegas Olmos, Juan José

    2013-01-01

    This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB.......This paper studies the application of beyond bound decoding method for high speed optical communications. This hard-decision decoding method outperforms traditional minimum distance decoding method, with a total net coding gain of 10.36 dB....

  18. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  19. Development of a Sweetness Sensor for Aspartame, a Positively Charged High-Potency Sweetener

    Directory of Open Access Journals (Sweden)

    Masato Yasuura

    2014-04-01

    Full Text Available Taste evaluation technology has been developed by several methods, such as sensory tests, electronic tongues and a taste sensor based on lipid/polymer membranes. In particular, the taste sensor can individually quantify five basic tastes without multivariate analysis. However, it has proven difficult to develop a sweetness sensor, because sweeteners are classified into three types according to the electric charges in an aqueous solution; that is, no charge, negative charge and positive charge. Using membrane potential measurements, the taste-sensing system needs three types of sensor membrane for each electric charge type of sweetener. Since the commercially available sweetness sensor was only intended for uncharged sweeteners, a sweetness sensor for positively charged high-potency sweeteners such as aspartame was developed in this study. Using a lipid and plasticizers, we fabricated various lipid/polymer membranes for the sweetness sensor to identify the suitable components of the sensor membranes. As a result, one of the developed sensors showed responses of more than 20 mV to 10 mM aspartame and less than 5 mV to any other taste. The responses of the sensor depended on the concentration of aspartame. These results suggested that the developed sweetness sensor had high sensitivity to and high selectivity for aspartame.

  20. Development of a sweetness sensor for aspartame, a positively charged high-potency sweetener.

    Science.gov (United States)

    Yasuura, Masato; Tahara, Yusuke; Ikezaki, Hidekazu; Toko, Kiyoshi

    2014-04-23

    Taste evaluation technology has been developed by several methods, such as sensory tests, electronic tongues and a taste sensor based on lipid/polymer membranes. In particular, the taste sensor can individually quantify five basic tastes without multivariate analysis. However, it has proven difficult to develop a sweetness sensor, because sweeteners are classified into three types according to the electric charges in an aqueous solution; that is, no charge, negative charge and positive charge. Using membrane potential measurements, the taste-sensing system needs three types of sensor membrane for each electric charge type of sweetener. Since the commercially available sweetness sensor was only intended for uncharged sweeteners, a sweetness sensor for positively charged high-potency sweeteners such as aspartame was developed in this study. Using a lipid and plasticizers, we fabricated various lipid/polymer membranes for the sweetness sensor to identify the suitable components of the sensor membranes. As a result, one of the developed sensors showed responses of more than 20 mV to 10 mM aspartame and less than 5 mV to any other taste. The responses of the sensor depended on the concentration of aspartame. These results suggested that the developed sweetness sensor had high sensitivity to and high selectivity for aspartame.

  1. High-speed optical feeder-link system using adaptive optics

    Science.gov (United States)

    Arimoto, Yoshinori; Hayano, Yutaka; Klaus, Werner

    1997-05-01

    We propose a satellite laser communication system between a ground station and a geostationary satellite, named high- speed optical feeder link system. It is based on the application of (a) high-speed optical devices, which have been developed for ground-based high-speed fiber-optic communications, and (b) the adaptive optics which compensates wavefront distortions due to atmospheric turbulences using a real time feedback control. A link budget study shows that a system with 10-Gbps bit-rate are available assuming the state-of-the-art device performance of the Er-doped fiber amplifier. We further discuss preliminary measurement results of the atmospheric turbulence at the telescope site in Tokyo, and present current study on the design of the key components for the feeder-link laser transceiver.

  2. Multi-frequency inversion-charge pumping for charge separation and mobility analysis in high-k/InGaAs metal-oxide-semiconductor field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Djara, V.; Cherkaoui, K.; Negara, M. A.; Hurley, P. K., E-mail: paul.hurley@tyndall.ie [Tyndall National Institute, University College Cork, Dyke Parade, Cork (Ireland)

    2015-11-28

    An alternative multi-frequency inversion-charge pumping (MFICP) technique was developed to directly separate the inversion charge density (N{sub inv}) from the trapped charge density in high-k/InGaAs metal-oxide-semiconductor field-effect transistors (MOSFETs). This approach relies on the fitting of the frequency response of border traps, obtained from inversion-charge pumping measurements performed over a wide range of frequencies at room temperature on a single MOSFET, using a modified charge trapping model. The obtained model yielded the capture time constant and density of border traps located at energy levels aligned with the InGaAs conduction band. Moreover, the combination of MFICP and pulsed I{sub d}-V{sub g} measurements enabled an accurate effective mobility vs N{sub inv} extraction and analysis. The data obtained using the MFICP approach are consistent with the most recent reports on high-k/InGaAs.

  3. High Bandwidth Optical Links for Micro-Satellite Support

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Wilson, Keith E. (Inventor); Coste, Keith (Inventor)

    2016-01-01

    A method, systems, apparatus and device enable high bandwidth satellite communications. An onboard tracking detector, installed in a low-earth orbit satellite, detects a position of an incoming optical beam received/transmitted from a first ground station of one or more ground stations. Tracker electronics determine orientation information of the incoming optical beam based on the position. Control electronics receive the orientation information from the tracker electronics, and control a waveguide drive electronics. The waveguide drive electronics control a voltage that is provided to an electro-optic waveguide beam steering device. The electro-optic waveguide beam steering device steers an outgoing optical beam to one of the one or more ground stations based on the voltage.

  4. Ultra-high Frequency Linear Fiber Optic Systems

    CERN Document Server

    Lau, Kam

    2011-01-01

    This book provides an in-depth treatment of both linear fiber-optic systems and their key enabling devices. It presents a concise but rigorous treatment of the theory and practice of analog (linear) fiber-optics links and systems that constitute the foundation of Hybrid Fiber Coax infrastructure in present-day CATV distribution and cable modem Internet access. Emerging applications in remote fiber-optic feed for free-space millimeter wave enterprise campus networks are also described. Issues such as dispersion and interferometric noise are treated quantitatively, and means for mitigating them are explained. This broad but concise text will thus be invaluable not only to students of fiber-optics communication but also to practicing engineers. To the second edition of this book important new aspects of linear fiber-optic transmission technologies are added, such as high level system architectural issues, algorithms for deriving the optimal frequency assignment, directly modulated or externally modulated laser t...

  5. Optical spatial differentiator based on subwavelength high-contrast gratings

    Science.gov (United States)

    Dong, Zhewei; Si, Jiangnan; Yu, Xuanyi; Deng, Xiaoxu

    2018-04-01

    An optical spatial differentiator based on subwavelength high-contrast gratings (HCGs) is proposed experimentally. The spatial differentiation property of the subwavelength HCG is analyzed by calculating its spatial spectral transfer function based on the periodic waveguide theory. By employing the FDTD solutions, the performance of the subwavelength HCG spatial differentiator was investigated numerically. The subwavelength HCG differentiator with the thickness at the nanoscale was fabricated on the quartz substrate by electron beam lithography and Bosch deep silicon etching. Observed under an optical microscope with a CCD camera, the spatial differentiation of the incident field profile was obtained by the subwavelength HCG differentiator in transmission without Fourier lens. By projecting the images of slits, letter "X," and a cross on the subwavelength HCG differentiator, edge detections of images were obtained in transmission. With the nanoscale HCG structure and simple optical implementation, the proposed optical spatial differentiator provides the prospects for applications in optical computing systems and parallel data processing.

  6. Electron transfer and decay processes of highly charged iodine ions

    International Nuclear Information System (INIS)

    Sakaue, Hiroyuki A.; Danjo, Atsunori; Hosaka, Kazumoto

    2005-01-01

    In the present experimental work we have investigated multi-electron transfer processes in I q+ (q=10, 15, 20 and 25) + Ne, Ar, Kr and Xe collisions at 1.5q keV energy. The branching ratios between Auger and radiative decay channels have been measured in decay processes of multiply excited states formed by multi-electron transfer collisions. It has been shown that, in all the multi-electron transfer processes investigated, the Auger decays are far dominant over the radiative decay processes and the branching ratios are clearly characterized by the average principal quantum number of the initial excited states of projectile ions. We could express the branching ratios in high Rydberg states formed in multi-electron transfer processes by using the decay probability of one Auger electron emission. (author)

  7. X-ray transitions in highly charged neonlike ions

    International Nuclear Information System (INIS)

    Beiersdorfer, P.; von Gjoeler, S.; Bitter, M.

    1987-11-01

    Wavelength measurements of n=3 to n=2 transitions in neonlike Xe 44+ , La 47+ , Nd 50+ , and Eu 53+ have been made using a high-resolution Bragg-crystal spectrometer on the Princeton Large Torus tokamak. The measurements cover the wavelength regions 2.00 to 3.00 (angstrom) and include the electric dipole, and the electric and magnetic quadrupole transitions. The measured wavelengths are compared to energy levels obtained from a multiconfigurational Dirac-Fock calculation. Systematic differences between the experimental and theoretical values are found, which vary smoothly with atomic number. The magnitude of the differences depends on the particular type of transition and ranges from -2.8 eV to +2.2 eV. Inclusion of electron correlation corrections due to ground state correlations and (super) Coster-Kronig type fluctuations in the theoretical energies is shown to reduce the differences for some but not all types of transitions

  8. Uncharted Frontiers in the Spectroscopy of Highly Charged Ions

    CERN Document Server

    Beiersdorfer, P; Crespo, J; Kim, S H; Neill, P; Utter, S; Widmann, K

    2000-01-01

    The development of novel techniques is critical for maintaining a state-of-the-art core competency in atomic physics and readiness for evolving programmatic needs. We have carried out a three-year effort to develop novel spectroscopic instrumentation that added new dimensions to our capabilities for measuring energy levels, radiative transition probabilities, and electron-ion excitation processes. The new capabilities created were in areas that heretofore had been inaccessible to scientific scrutiny and included high-resolution spectroscopy of hard x rays, femtosecond lifetime measurements, measurements of transition probabilities of long-lived metastable levels, polarization spectroscopy, ultra-precise determinations of energy levels, and the establishment of absolute wavelength standards in x-ray spectroscopy. Instrumentation developed during the period included a transmission-type crystal spectrometer, a flat-field EUV spectrometer, and the development and deployment of absolutely calibrated monolithic cry...

  9. Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency

    Science.gov (United States)

    Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A.; Chen, Ying-Cheng

    2018-05-01

    Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

  10. Simulation of Space Charge Effects in Electron Optical System Based on the Calculations of Current Density

    Czech Academy of Sciences Publication Activity Database

    Zelinka, Jiří; Oral, Martin; Radlička, Tomáš

    2015-01-01

    Roč. 21, S4 (2015), s. 246-251 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : electron optical system * calculations of current density Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.730, year: 2015

  11. Beam dynamics of mixed high intensity highly charged ion Beams in the Q/A selector

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.H., E-mail: zhangxiaohu@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yuan, Y.J.; Yin, X.J.; Qian, C.; Sun, L.T. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Du, H.; Li, Z.S.; Qiao, J.; Wang, K.D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H.W.; Xia, J.W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2017-06-11

    Electron cyclotron resonance (ECR) ion sources are widely used in heavy ion accelerators for their advantages in producing high quality intense beams of highly charged ions. However, it exists challenges in the design of the Q/A selection systems for mixed high intensity ion beams to reach sufficient Q/A resolution while controlling the beam emittance growth. Moreover, as the emittance of beam from ECR ion sources is coupled, the matching of phase space to post accelerator, for a wide range of ion beam species with different intensities, should be carefully studied. In this paper, the simulation and experimental results of the Q/A selection system at the LECR4 platform are shown. The formation of hollow cross section heavy ion beam at the end of the Q/A selector is revealed. A reasonable interpretation has been proposed, a modified design of the Q/A selection system has been committed for HIRFL-SSC linac injector. The features of the new design including beam simulations and experiment results are also presented.

  12. High pressure study of high temperatures superconductors: Material base, universal Tc-behavior, and charge transfer

    International Nuclear Information System (INIS)

    Chu, C.W.; Hor, P.H.; Lin, J.G.; Xiong, Q.; Huang, Z.J.; Meng, R.L.; Xue, Y.Y.; Jean, Y.C.

    1991-01-01

    The superconducting transition temperature (T c ) has been measured in YBa 2 Cu 3 O 6.7 , YBa 2 Cu 3 O 7 , Y 2 Ba 4 Cu 7 O 15 , YBa 2 Cu 4 O 8 , Tl 2 Ba 2 Ca n-1 Cu n O n+4-δ , La 2-x Sr x CuO 4 , and La 2-x Ba x CuO 4 under high pressures. The pressure effect on the positron lifetime (τ) has also been determined in the first four compounds. Based on these and other high pressure data, the authors suggest that (1) all known cuprate high temperature superconductors (HTS's) may be no more than mere modifications of either 214-T, 214-T', 123, or a combination of 214-T' and 123, (2) a nonmonotonic T c -behavior may govern the T c -variation of all hole cuprate HTS's and (3) pressure can induce charge transfer leading to a T c -change. The implications of these suggestions will also be discussed

  13. Evaporation and discharge dynamics of highly charged multicomponent droplets generated by electrospray ionization.

    Science.gov (United States)

    Grimm, Ronald L; Beauchamp, J L

    2010-01-28

    We investigate the Rayleigh discharge and evaporation dynamics of highly charged two-component droplets consisting principally of methanol with 2-methoxyethanol, tert-butanol, or m-nitrobenzyl alcohol. A phase Doppler anemometer (PDA) characterizes droplets generated by electrospray ionization (ESI) according to size, velocity, and charge as they move through a uniform electric field within an ion mobility spectrometer (IMS). Repeated field reversals result in droplet "ping-pong" through the PDA. This generates individual droplet histories of solvent evaporation behavior and the dynamics of charge loss to progeny droplets during Rayleigh discharge events. On average, methanol droplets discharge at 127% their Rayleigh limit of charge, q(R), and release 25% of the net charge. Charge loss from methanol/2-methoxyethanol droplets behaves similarly to pure 2-methoxyethanol droplets which release approximately 28% of their net charge. Binary methanol droplets containing up to 50% tert-butanol discharge at a lower percent q(R) than pure methanol and release a greater fraction of their net charge. Mixed 99% methanol/1% m-nitrobenzyl alcohol droplets possess discharge characteristics similar to those of methanol. However, droplets of methanol containing 2% m-nitrobenzyl evaporate down to a fixed size and charge that remains constant with no observable discharges. Quasi-steady-state evaporation models accurately describe observed evaporation phenomena in which methanol/tert-butanol droplets evaporate at a rate similar to that of pure methanol and methanol/2-methoxyethanol droplets evaporate at a rate similar to that of 2-methoxyethanol. We compare these results to previous Rayleigh discharge experiments and discuss the implications for binary solvents in electrospray mass spectrometry (ESI-MS) and field-induced droplet ionization mass spectrometry (FIDI-MS).

  14. Review of highly charged heavy ion production with electron cyclotron resonance ion source (invited)

    International Nuclear Information System (INIS)

    Nakagawa, T.

    2014-01-01

    The electron cyclotron resonance ion source (ECRIS) plays an important role in the advancement of heavy ion accelerators and other ion beam applications worldwide, thanks to its remarkable ability to produce a great variety of intense highly charged heavy ion beams. Great efforts over the past decade have led to significant ECRIS performance improvements in both the beam intensity and quality. A number of high-performance ECRISs have been built and are in daily operation or are under construction to meet the continuously increasing demand. In addition, comprehension of the detailed and complex physical processes in high-charge-state ECR plasmas has been enhanced experimentally and theoretically. This review covers and discusses the key components, leading-edge developments, and enhanced ECRIS performance in the production of highly charged heavy ion beams

  15. A High-Level Functional Architecture for GNSS-Based Road Charging Systems

    DEFF Research Database (Denmark)

    Zabic, Martina

    2011-01-01

    , a short introduction is provided followed by a presentation of the system engineering methodology to illustrate how and why system architectures can be beneficial for GNSS-based road charging systems. Hereafter, a basic set of system functions is determined based on functional system requirements, which...... charging systems, it is important to highlight the overall system architecture which is the framework that defines the basic functions and important concepts of the system. This paper presents a functional architecture for GNSS-based road charging systems based on the concepts of system engineering. First...... defines the necessary tasks that these systems must accomplish. Finally, this paper defines the system functionalities; and provides a generic high-level functional architecture for GNSS-based road charging systems....

  16. Practical Approaches to Mitigation of Specimen Charging in High-Resolution Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Young-Min Kim

    2010-09-01

    Full Text Available Specimen charging that is associated with the electron bombardment on the sample is a practical hindrance to high-resolution transmission electron microscopy (HRTEM analysis because it causes a severe loss of resolution in either diffraction or image data. Conductive thin film deposition on an insulating specimen has been proposed as an effective approach to the mitigation of the specimen charging; however, this method is generally not useful in HRTEM imaging of materials because the deposited film induces another artifact in the HRTEM image contrast. In this study, we propose practical methods to mitigate the specimen charging that takes place during the HRTEM of materials. For bulk-type specimens prepared by either an ion-thinning or focused-ion beam (FIB process, a plasma cleaning treatment is significantly effective in eliminating the charging phenomenon. In the case of low-dimensional nanomaterials such as nanowires and nanoparticles, the plasma cleaning is not feasible; however, the charging effect can be effectively eliminated by adjusting the electron illumination condition. The proposed methods facilitate a decrease in the buildup of specimen charging, thereby enhancing the quality of high-resolution images significantly.

  17. Techniques for enhancing the performance of high charge state ECR ion sources

    International Nuclear Information System (INIS)

    Xie, Z.Q.

    1999-01-01

    Electron Cyclotron Resonance ion source (ECRIS), which produces singly to highly charged ions, is widely used in heavy ion accelerators and is finding applications in industry. It has progressed significantly in recent years thanks to a few techniques, such as multiple-frequency plasma heating, higher mirror magnetic fields and a better cold electron donor. These techniques greatly enhance the production of highly charged ions. More than 1 emA of He 2+ and O 6+ , hundreds of eμA of O 7+ , Ne 8+ , Ar 12+ , more than 100 eμA of intermediate heavy ions with charge states up to Ne 9+ , Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ and Kr 18+ , tens of eμA of heavy ions with charge states up to Xe 28+ , Au 35+ , Bi 34+ and U 34+ were produced at cw mode operation. At an intensity of about 1 eμA, the charge states for the heavy ions increased up to Xe 36+ , Au 46+ , Bi 47+ and U 48+ . More than an order of magnitude enhancement of fully stripped argon ions was achieved (I≥0.1 and h;eμA). Higher charge state ions up to Kr 35+ , Xe 46+ and U 64+ at low intensities were produced for the first time from an ECRIS. copyright 1999 American Institute of Physics

  18. Ultrafast electron microscopy: Instrument response from the single-electron to high bunch-charge regimes

    Science.gov (United States)

    Plemmons, Dayne A.; Flannigan, David J.

    2017-09-01

    We determine the instrument response of an ultrafast electron microscope equipped with a conventional thermionic electron gun and absent modifications beyond the optical ports. Using flat, graphite-encircled LaB6 cathodes, we image space-charge effects as a function of photoelectron-packet population and find that an applied Wehnelt bias has a negligible effect on the threshold levels (>103 electrons per pulse) but does appear to suppress blurring at the upper limits (∼105 electrons). Using plasma lensing, we determine the instrument-response time for 700-fs laser pulses and find that single-electron packets are laser limited (1 ps), while broadening occurs well below the space-charge limit.

  19. Extraction Compression and Acceleration of High Line Charge Density Ion Beams

    CERN Document Server

    Henestroza, Enrique; Grote, D P; Peters, Craig; Yu, Simon

    2005-01-01

    HEDP applications require high line charge density ion beams. An efficient method to obtain this type of beams is to extract a long pulse, high current beam from a gun at high energy, and let the beam pass through a decelerating field to compress it. The low energy beam bunch is loaded into a solenoid and matched to a Brillouin flow. The Brillouin equilibrium is independent of the energy if the relationship between the beam size (a), solenoid magnetic field strength (B) and line charge density is such that (Ba)2

  20. New experimental initiatives using very highly charged ions from an 'electron beam ion trap'

    International Nuclear Information System (INIS)

    Schneider, D.

    1996-01-01

    A short review of the experimental program in highly-charged heavy ion physics conducted at the Lawrence Livermore National Laboratory Electron Beam Ion Trap (EBIT) facility is presented. The heavy-ion research, involving ions up to fully stripped U 92+ , includes precision x-ray spectroscopy and lifetime studies, electron impact ionization and excitation cross section measurements. The investigations of ion-surface interactions following the impact of high-Z highly charged ions on surfaces are aimed to study the neutralization dynamics effecting the ion and the response of the surface as well. (author)

  1. Charge-exchange-induced formation of hollow atoms in high-intensity laser-produced plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rosmej, F.B. [TU-Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Faenov, A.Ya.; Pikuz, T.A.; Magunov, A.I.; Skobelev, I.Yu. [Multicharged Ions Spectra Data Center of VNIIFTRI, Mendeleevo (Russian Federation); Auguste, T.; D' Oliveira, P.; Hulin, S.; Monot, P. [Commissariat a lEnergie Atomique DSM/DRECAM/SPAM, Gif-Sur-Yvette Cedex (France); Andreev, N.E.; Chegotov, M.V.; Veisman, M.E. [High Energy Density Research Centre, Institute of High Temperatures of Russian Academy of Sciences, Moscow (Russian Federation)

    1999-03-14

    For the first time registration of high-resolution soft x-ray emission and atomic data calculations of hollow-atom dielectronic satellite spectra of highly charged nitrogen have been performed. Double-electron charge-exchange processes from excited states are proposed for the formation of autoionizing levels nln'l' in high-intensity laser-produced plasmas, when field-ionized ions penetrate into the residual gas. Good agreement is found between theory and experiment. Plasma spectroscopy with hollow ions is proposed and a temperature diagnostic for laser-produced plasmas in the long-lasting recombining regime is developed. (author). Letter-to-the-editor.

  2. Optical Characteristics of a Multichannel Hybrid Integrated Light Source for Ultra-High-Bandwidth Optical Interconnections

    Directory of Open Access Journals (Sweden)

    Takanori Shimizu

    2015-11-01

    Full Text Available The optical characteristics of a multi-channel hybrid integrated light source were described for an optical interconnection with a bandwidth of over 10 Tbit/s. The power uniformity of the relative intensity of a 1000-channel light source was shown, and the minimum standard deviation s of the optical power of the 200 output ports at each 25-channel laser diode (LD array was estimated to be 0.49 dB. This hybrid integrated light source is expected to be easily adaptable to a photonics-electronics convergence system for ultra-high-bandwidth interchip interconnections.

  3. Charge-sign-clustering observed in high-multiplicity, high-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Takahashi, Y.; Gregory, J.C.; Hayashi, T.

    1989-01-01

    Charge-sign distribution in 200 GeV/amu heavy-ion collisions is studied with the Magnetic-Interferometric-Emulsion-Chamber (MAGIC) for central collision events in 16 O + Pb and 32 S + Pb interactions. Charge-sign clustering is observed in most of the fully-analyzed events. A statistical 'run-test' is performed for each measured event, which shows significant deviation from a Gaussian distribution (0,1) expected for random-charge distribution. Candidates of charge clusters have 5 - 10 multiplicity of like-sign particles, and are often accompanied by opposite-sign clusters. Observed clustering of identical charges is more significant in the fragmentation region than in the central region. Two-particle Bose-Einstein interference and other effects are discussed for the run-test examination. (author)

  4. Recent progress on high-speed optical transmission

    Directory of Open Access Journals (Sweden)

    Jianjun Yu

    2016-05-01

    Full Text Available The recently reported high spectral efficiency (SE and high-baud-rate signal transmission are all based on digital coherent optical communications and digital signal processing (DSP. DSP simplifies the reception of advanced modulation formats and also enables the major electrical and optical impairments to be processed and compensated in the digital domain, at the transmitter or receiver side. In this paper, we summarize the research progress on high-speed signal generation and detection and also show the progress on DSP for high-speed signal detection. We also report the latest progress on multi-core and multi-mode multiplexing.

  5. High-throughput proteomics : optical approaches.

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, George S.

    2008-09-01

    Realistic cell models could greatly accelerate our ability to engineer biochemical pathways and the production of valuable organic products, which would be of great use in the development of biofuels, pharmaceuticals, and the crops for the next green revolution. However, this level of engineering will require a great deal more knowledge about the mechanisms of life than is currently available. In particular, we need to understand the interactome (which proteins interact) as it is situated in the three dimensional geometry of the cell (i.e., a situated interactome), and the regulation/dynamics of these interactions. Methods for optical proteomics have become available that allow the monitoring and even disruption/control of interacting proteins in living cells. Here, a range of these methods is reviewed with respect to their role in elucidating the interactome and the relevant spatial localizations. Development of these technologies and their integration into the core competencies of research organizations can position whole institutions and teams of researchers to lead in both the fundamental science and the engineering applications of cellular biology. That leadership could be particularly important with respect to problems of national urgency centered around security, biofuels, and healthcare.

  6. Scalable Active Optical Access Network Using Variable High-Speed PLZT Optical Switch/Splitter

    Science.gov (United States)

    Ashizawa, Kunitaka; Sato, Takehiro; Tokuhashi, Kazumasa; Ishii, Daisuke; Okamoto, Satoru; Yamanaka, Naoaki; Oki, Eiji

    This paper proposes a scalable active optical access network using high-speed Plumbum Lanthanum Zirconate Titanate (PLZT) optical switch/splitter. The Active Optical Network, called ActiON, using PLZT switching technology has been presented to increase the number of subscribers and the maximum transmission distance, compared to the Passive Optical Network (PON). ActiON supports the multicast slot allocation realized by running the PLZT switch elements in the splitter mode, which forces the switch to behave as an optical splitter. However, the previous ActiON creates a tradeoff between the network scalability and the power loss experienced by the optical signal to each user. It does not use the optical power efficiently because the optical power is simply divided into 0.5 to 0.5 without considering transmission distance from OLT to each ONU. The proposed network adopts PLZT switch elements in the variable splitter mode, which controls the split ratio of the optical power considering the transmission distance from OLT to each ONU, in addition to PLZT switch elements in existing two modes, the switching mode and the splitter mode. The proposed network introduces the flexible multicast slot allocation according to the transmission distance from OLT to each user and the number of required users using three modes, while keeping the advantages of ActiON, which are to support scalable and secure access services. Numerical results show that the proposed network dramatically reduces the required number of slots and supports high bandwidth efficiency services and extends the coverage of access network, compared to the previous ActiON, and the required computation time for selecting multicast users is less than 30msec, which is acceptable for on-demand broadcast services.

  7. Space charge inhibition effect of nano-Fe{sub 3}O{sub 4} on improvement of impulse breakdown voltage of transformer oil based on improved Kerr optic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qing, E-mail: yangqing@cqu.edu.cn; Yu, Fei; Sima, Wenxia [State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Shapingba District, Chongqing, 400044 (China); Zahn, Markus [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2015-09-15

    Transformer oil-based nanofluids (NFs) with 0.03 g/L Fe{sub 3}O{sub 4} nanoparticle content exhibit 11.2% higher positive impulse breakdown voltage levels than pure transformer oils. To study the effects of the Fe{sub 3}O{sub 4} nanoparticles on the space charge in transformer oil and to explain why the nano-modified transformer oil exhibits improved impulse breakdown voltage characteristics, the traditional Kerr electro-optic field mapping technique is improved by increasing the length of the parallel-plate electrodes and by using a photodetector array as a high light sensitivity device. The space charge distributions of pure transformer oil and of NFs containing Fe{sub 3}O{sub 4} nanoparticles can be measured using the improved Kerr electro-optic field mapping technique. Test results indicate a significant reduction in space charge density in the transformer oil-based NFs with the Fe{sub 3}O{sub 4} nanoparticles. The fast electrons are captured by the nanoparticles and are converted into slow-charged particles in the NFs, which then reduce the space charge density and result in a more uniform electric field distribution. Streamer propagation in the NFs is also obstructed, and the breakdown strengths of the NFs under impulse voltage conditions are also improved.

  8. High-Order Modulation for Optical Fiber Transmission

    CERN Document Server

    Seimetz, Matthias

    2009-01-01

    Catering to the current interest in increasing the spectral efficiency of optical fiber networks by the deployment of high-order modulation formats, this monograph describes transmitters, receivers and performance of optical systems with high-order phase and quadrature amplitude modulation. In the first part of the book, the author discusses various transmitter implementation options as well as several receiver concepts based on direct and coherent detection, including designs of new structures. Hereby, both optical and electrical parts are considered, allowing the assessment of practicability and complexity. In the second part, a detailed characterization of optical fiber transmission systems is presented, regarding a wide range of modulation formats. It provides insight in the fundamental behavior of different formats with respect to relevant performance degradation effects and identifies the major trends in system performance.

  9. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.

    2016-05-16

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  10. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dö rling, Bernhard; Ashraf, Raja Shahid; Goñ i, Alejandro R.; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C.; Campoy-Quiles, Mariano; Nelson, Jenny

    2016-01-01

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  11. Compact, Energy-Efficient High-Frequency Switched Capacitor Neural Stimulator With Active Charge Balancing.

    Science.gov (United States)

    Hsu, Wen-Yang; Schmid, Alexandre

    2017-08-01

    Safety and energy efficiency are two major concerns for implantable neural stimulators. This paper presents a novel high-frequency, switched capacitor (HFSC) stimulation and active charge balancing scheme, which achieves high energy efficiency and well-controlled stimulation charge in the presence of large electrode impedance variations. Furthermore, the HFSC can be implemented in a compact size without any external component to simultaneously enable multichannel stimulation by deploying multiple stimulators. The theoretical analysis shows significant benefits over the constant-current and voltage-mode stimulation methods. The proposed solution was fabricated using a 0.18 μm high-voltage technology, and occupies only 0.035 mm 2 for a single stimulator. The measurement result shows 50% peak energy efficiency and confirms the effectiveness of active charge balancing to prevent the electrode dissolution.

  12. Review of high bandwidth fiber optics radiation sensors

    International Nuclear Information System (INIS)

    Lyons, P.B.

    1985-01-01

    This paper summarizes the use of fiber optics or guided optical systems for radiation sensors. It is limited a passive systems wherein electrical is not required at the sensor location. However, electrically powered light sources, receivers and/or recorders may still be required for detection and data storage in sensor system operation. This paper emphasizes sensor technologies that permit high bandwidth measurements of transient radiation levels, and will also discuss several low bandwidth applications. 60 refs

  13. ACIGA's high optical power test facility

    Energy Technology Data Exchange (ETDEWEB)

    Ju, L [School of Physics, University of Western Australia, Perth (Australia); Aoun, M [Computer and Information Science, Edith Cowan University, Perth (Australia); Barriga, P [School of Physics, University of Western Australia, Perth (Australia)] [and others

    2004-03-07

    Advanced laser interferometer detectors utilizing more than 100 W of laser power and with {approx}10{sup 6} W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties.

  14. Concept and design of charged particle optics using energy Fourier plane collimation

    Science.gov (United States)

    Yang, Guojun; Wei, Tao; Zhang, Zhuo; He, Xiaozhong; Zhang, Xiaoding; Li, Yiding; Shi, Jinshui

    2014-09-01

    Charged particle radiography has become a promising new approach in the field of transmission radiography because of the invention of the magnetic imaging lens. The using of the imaging lens makes it possible for thick objects to get significantly improved transmission radiography. Currently, the conventional charged particle radiography only uses the information of the flux attenuation and the angular scattering of the transmitted particles to determine the properties of the sample. However, the energy loss of the incident particles introduced by ionizations throughout the object limits the spatial resolution of the image because of the chromatic blur. In this paper a new concept of imaging lens that uses the information of the energy loss is proposed. With a specially designed imaging lens, the information of the energy loss could result in apparent contrast in the final image. This design procedure of the energy loss imaging lens is presented, and a preliminary design is verified by numerical simulations. Experimental demonstration is also expected on a cyclotron at the Institute of Fluid Physics, CAEP.

  15. Concept and design of charged particle optics using energy Fourier plane collimation

    Directory of Open Access Journals (Sweden)

    Guojun Yang

    2014-09-01

    Full Text Available Charged particle radiography has become a promising new approach in the field of transmission radiography because of the invention of the magnetic imaging lens. The using of the imaging lens makes it possible for thick objects to get significantly improved transmission radiography. Currently, the conventional charged particle radiography only uses the information of the flux attenuation and the angular scattering of the transmitted particles to determine the properties of the sample. However, the energy loss of the incident particles introduced by ionizations throughout the object limits the spatial resolution of the image because of the chromatic blur. In this paper a new concept of imaging lens that uses the information of the energy loss is proposed. With a specially designed imaging lens, the information of the energy loss could result in apparent contrast in the final image. This design procedure of the energy loss imaging lens is presented, and a preliminary design is verified by numerical simulations. Experimental demonstration is also expected on a cyclotron at the Institute of Fluid Physics, CAEP.

  16. High-k shallow traps observed by charge pumping with varying discharging times

    International Nuclear Information System (INIS)

    Ho, Szu-Han; Chen, Ching-En; Tseng, Tseung-Yuen; Chang, Ting-Chang; Lu, Ying-Hsin; Lo, Wen-Hung; Tsai, Jyun-Yu; Liu, Kuan-Ju; Wang, Bin-Wei; Cao, Xi-Xin; Chen, Hua-Mao; Cheng, Osbert; Huang, Cheng-Tung; Chen, Tsai-Fu

    2013-01-01

    In this paper, we investigate the influence of falling time and base level time on high-k bulk shallow traps measured by charge pumping technique in n-channel metal-oxide-semiconductor field-effect transistors with HfO 2 /metal gate stacks. N T -V high level characteristic curves with different duty ratios indicate that the electron detrapping time dominates the value of N T for extra contribution of I cp traps. N T is the number of traps, and I cp is charge pumping current. By fitting discharge formula at different temperatures, the results show that extra contribution of I cp traps at high voltage are in fact high-k bulk shallow traps. This is also verified through a comparison of different interlayer thicknesses and different Ti x N 1−x metal gate concentrations. Next, N T -V high level characteristic curves with different falling times (t falling time ) and base level times (t base level ) show that extra contribution of I cp traps decrease with an increase in t falling time . By fitting discharge formula for different t falling time , the results show that electrons trapped in high-k bulk shallow traps first discharge to the channel and then to source and drain during t falling time . This current cannot be measured by the charge pumping technique. Subsequent measurements of N T by charge pumping technique at t base level reveal a remainder of electrons trapped in high-k bulk shallow traps

  17. Ultra-high accuracy optical testing: creating diffraction-limitedshort-wavelength optical systems

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman,Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli,Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-08-03

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-{angstrom} and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date.

  18. Ultra-high accuracy optical testing: creating diffraction-limited short-wavelength optical systems

    International Nuclear Information System (INIS)

    Goldberg, Kenneth A.; Naulleau, Patrick P.; Rekawa, Senajith B.; Denham, Paul E.; Liddle, J. Alexander; Gullikson, Eric M.; Jackson, KeithH.; Anderson, Erik H.; Taylor, John S.; Sommargren, Gary E.; Chapman, Henry N.; Phillion, Donald W.; Johnson, Michael; Barty, Anton; Soufli, Regina; Spiller, Eberhard A.; Walton, Christopher C.; Bajt, Sasa

    2005-01-01

    Since 1993, research in the fabrication of extreme ultraviolet (EUV) optical imaging systems, conducted at Lawrence Berkeley National Laboratory (LBNL) and Lawrence Livermore National Laboratory (LLNL), has produced the highest resolution optical systems ever made. We have pioneered the development of ultra-high-accuracy optical testing and alignment methods, working at extreme ultraviolet wavelengths, and pushing wavefront-measuring interferometry into the 2-20-nm wavelength range (60-600 eV). These coherent measurement techniques, including lateral shearing interferometry and phase-shifting point-diffraction interferometry (PS/PDI) have achieved RMS wavefront measurement accuracies of 0.5-1-(angstrom) and better for primary aberration terms, enabling the creation of diffraction-limited EUV optics. The measurement accuracy is established using careful null-testing procedures, and has been verified repeatedly through high-resolution imaging. We believe these methods are broadly applicable to the advancement of short-wavelength optical systems including space telescopes, microscope objectives, projection lenses, synchrotron beamline optics, diffractive and holographic optics, and more. Measurements have been performed on a tunable undulator beamline at LBNL's Advanced Light Source (ALS), optimized for high coherent flux; although many of these techniques should be adaptable to alternative ultraviolet, EUV, and soft x-ray light sources. To date, we have measured nine prototype all-reflective EUV optical systems with NA values between 0.08 and 0.30 (f/6.25 to f/1.67). These projection-imaging lenses were created for the semiconductor industry's advanced research in EUV photolithography, a technology slated for introduction in 2009-13. This paper reviews the methods used and our program's accomplishments to date

  19. Spectral evolution of soft x-ray emission from optically thin, high electron temperature platinum plasmas

    Directory of Open Access Journals (Sweden)

    Hiroyuki Hara

    2017-08-01

    Full Text Available The soft x-ray spectra of heavy element plasmas are frequently dominated by unresolved transition array (UTA emission. We describe the spectral evolution of an intense UTA under optically thin conditions in platinum plasmas. The UTA was observed to have a peak wavelength around 4.6 nm at line-of-sight averaged electron temperatures less than 1.4 keV at electron densities of (2.5–7.5 × 1013 cm−3. The UTA spectral structure was due to emission from 4d–4f transitions in highly charged ions with average charge states of q = 20–40. A numerical simulation successfully reproduced the observed spectral behavior.

  20. High-Throughput Block Optical DNA Sequence Identification.

    Science.gov (United States)

    Sagar, Dodderi Manjunatha; Korshoj, Lee Erik; Hanson, Katrina Bethany; Chowdhury, Partha Pratim; Otoupal, Peter Britton; Chatterjee, Anushree; Nagpal, Prashant

    2018-01-01

    Optical techniques for molecular diagnostics or DNA sequencing generally rely on small molecule fluorescent labels, which utilize light with a wavelength of several hundred nanometers for detection. Developing a label-free optical DNA sequencing technique will require nanoscale focusing of light, a high-throughput and multiplexed identification method, and a data compression technique to rapidly identify sequences and analyze genomic heterogeneity for big datasets. Such a method should identify characteristic molecular vibrations using optical spectroscopy, especially in the "fingerprinting region" from ≈400-1400 cm -1 . Here, surface-enhanced Raman spectroscopy is used to demonstrate label-free identification of DNA nucleobases with multiplexed 3D plasmonic nanofocusing. While nanometer-scale mode volumes prevent identification of single nucleobases within a DNA sequence, the block optical technique can identify A, T, G, and C content in DNA k-mers. The content of each nucleotide in a DNA block can be a unique and high-throughput method for identifying sequences, genes, and other biomarkers as an alternative to single-letter sequencing. Additionally, coupling two complementary vibrational spectroscopy techniques (infrared and Raman) can improve block characterization. These results pave the way for developing a novel, high-throughput block optical sequencing method with lossy genomic data compression using k-mer identification from multiplexed optical data acquisition. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Interaction of slow highly-charged ions with metals and insulators

    International Nuclear Information System (INIS)

    Yamazaki, Y.

    2007-01-01

    Interaction of slow highly charged ions with insulator as well as metallic surfaces is discussed. In addition to the usual flat surface targets, studies with thin foils having a multitude of straight holes of ∼100 nm in diameter (micro-capillary foil) are introduced, which provide various unique information on the above surface interaction. In the case of an insulator micro-capillary foil, a so-called guiding effect was observed, where slow highly charged ions can transmit through the capillary tunnel keeping their initial charge state even when the capillary axis is tilted against the incident beam. A similar guiding effect has recently been found for slow highly-charged ions transmitted through a single tapered glass capillary. In both cases, the guiding effects are expected to be governed by a self-organized charging and discharging of the inner-wall of the insulator capillary. One of the prominent features of this guiding effect with the tapered capillary is the formation of a nano-size beam, which can be applied in various fields of science including surface nano-modification/analysis, nano-surgery of living cells, etc

  2. Observation of visible and uv magnetic dipole transitions in highly charged xenon and barium

    International Nuclear Information System (INIS)

    Morgan, C.A.; Serpa, F.G.; Takacs, E.; Meyer, E.S.; Gillaspy, J.D.; Sugar, J.; Roberts, J.R.; Brown, C.M.; Feldman, U.

    1995-01-01

    We have observed an unusual transition which is predicted to result in visible and near-uv emission from very highly charged titaniumlike ions spanning the entire upper half of the periodic table. Measurements of the wavelengths of the 3d 4 D 2 - 5 D 3 transitions in Ba +34 and Xe +32 are in surprisingly poor agreement with ab initio calculations. This work was carried out in an electron beam ion trap and demonstrates that such a device can be an important tool for visible spectroscopy of highly charged ions

  3. Possible Diamond-Like Nanoscale Structures Induced by Slow Highly-Charged Ions on Graphite (HOPG)

    Energy Technology Data Exchange (ETDEWEB)

    Sideras-Haddad, E.; Schenkel, T.; Shrivastava, S.; Makgato, T.; Batra, A.; Weis, C. D.; Persaud, A.; Erasmus, R.; Mwakikunga, B.

    2009-01-06

    The interaction between slow highly-charged ions (SHCI) of different charge states from an electron-beam ion trap and highly oriented pyrolytic graphite (HOPG) surfaces is studied in terms of modification of electronic states at single-ion impact nanosizeareas. Results are presented from AFM/STM analysis of the induced-surface topological features combined with Raman spectroscopy. I-V characteristics for a number of different impact regions were measured with STM and the results argue for possible formation of diamond-like nanoscale structures at the impact sites.

  4. Modelling of prompt losses of high energy charged particles in Tokamaks

    International Nuclear Information System (INIS)

    Dillner, Oe.; Anderson, D.; Hamnen, H.; Lisak, M.

    1990-01-01

    A simple analytical expression for the total prompt loss fraction of high energy charged particles in an axisymmetric Tokamak is derived. The results are compared with predictions obtained from numerical simulations and show good agreement. An application is made to sawtooth induced changes in the losses of fusion generated high energy charged particles. Particular emphasis is given to the importance of sawtooth induced profile changes of the background ion densities and temperature as well as to redistribution of particles which have accumulated during the sawtooth rise but are being lost by redistribution at the sawtooth crash. (au)

  5. X-ray emission in slow highly charged ion-surface collisions

    International Nuclear Information System (INIS)

    Watanabe, H; Abe, T; Fujita, Y; Sun, J; Takahashi, S; Tona, M; Yoshiyasu, N; Nakamura, N; Sakurai, M; Yamada, C; Ohtani, S

    2007-01-01

    X-rays emitted in the collisions of highly charged ions with a surface have been measured to investigate dissipation schemes of their potential energies. While 8.1% of the potential energy was dissipated in the collisions of He-like I ions with a W surface, 29.1% has been dissipated in the case of He-like Bi ions. The x-ray emissions play significant roles in the dissipation of the potential energies in the interaction of highly charged heavy ions with the surface

  6. Improvement of highly charged ion production in the ECR source of heavy ions

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1996-01-01

    Some physical limitations of the highly charged ion production in the ECR source are analyzed in this report. A few possible ways to improve the output of highly charged ions from the ECR source for heavy ions are proposed. A new library of computer codes for the numerical simulation of heavy ion production in the ECR ion source is used to examine these ways to improve the ECR source operation according to the CERN program of heavy ion acceleration. copyright 1996 American Institute of Physics

  7. Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

    Science.gov (United States)

    Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

    2013-01-01

    We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

  8. Possibility of resonant capture of antiprotons by highly charged hydrogenlike ions

    International Nuclear Information System (INIS)

    Genkin, M.; Lindroth, E.

    2009-01-01

    Recently, an experimental setup was proposed by Lapierre et al. which would allow antiprotons and highly charged ions to collide repeatedly in an electron beam ion trap (EBIT) due to a nested trap configuration. As mentioned by the authors, such a setup may open the possibility to study antiproton capture into well-defined states through a resonant process which involves simultaneous electron excitation. In the present work, we give some theoretical estimations of the feasibility of that process. It appears that the exotic dielectronic-like process of resonant anti-proton capture in highly charged ions does not seem to be completely out of reach

  9. Emulsifier-free emulsion polymerization produces highly charged, monodisperse particles for near infrared photonic crystals.

    Science.gov (United States)

    Reese, Chad E; Asher, Sanford A

    2002-04-01

    We have developed emulsifier-free, emulsion polymerization recipes for the synthesis of highly charged, monodisperse latex particles of diameters between 500 and 1100 nm. These latexes consist of poly[styrene-(co-2-hydroxyethyl methacrylate)] spherical particles whose surfaces are functionalized with sulfate and carboxylic acid groups. These highly charged, monodisperse particles readily self-assemble into robust, three-dimensionally ordered crystalline colloidal array photonic crystals that Bragg diffract light in the near infrared spectral region. By altering the particle number density, the diffraction wavelength can be tuned from approximately 1000 to approximately 4000 nm.

  10. Generation of annular, high-charge electron beams at the Argonne wakefield accelerator

    Science.gov (United States)

    Wisniewski, E. E.; Li, C.; Gai, W.; Power, J.

    2012-12-01

    We present and discuss the results from the experimental generation of high-charge annular(ring-shaped)electron beams at the Argonne Wakefield Accelerator (AWA). These beams were produced by using laser masks to project annular laser profiles of various inner and outer diameters onto the photocathode of an RF gun. The ring beam is accelerated to 15 MeV, then it is imaged by means of solenoid lenses. Transverse profiles are compared for different solenoid settings. Discussion includes a comparison with Parmela simulations, some applications of high-charge ring beams,and an outline of a planned extension of this study.

  11. High quality-factor optical resonators

    International Nuclear Information System (INIS)

    Henriet, Rémi; Salzenstein, Patrice; Coillet, Aurélien; Saleh, Khaldoun; Chembo, Yanne K; Ristic, Davor; Ferrari, Maurizio; Mortier, Michel; Rasoloniaina, Alphonse; Dumeige, Yannick; Féron, Patrice; Cibiel, Gilles; Llopis, Olivier

    2014-01-01

    Various resonators are investigated for microwave photonic applications. Micro-sphere, disk and fiber ring resonators were designed, realized and characterized. Obtained quality factors are as high as Q = 10 10 . (paper)

  12. Ultra-high-speed Optical Signal Processing using Silicon Photonics

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Ji, Hua; Jensen, Asger Sellerup

    with a photonic layer on top to interconnect them. For such systems, silicon is an attractive candidate enabling both electronic and photonic control. For some network scenarios, it may be beneficial to use optical on-chip packet switching, and for high data-density environments one may take advantage...... of the ultra-fast nonlinear response of silicon photonic waveguides. These chips offer ultra-broadband wavelength operation, ultra-high timing resolution and ultra-fast response, and when used appropriately offer energy-efficient switching. In this presentation we review some all-optical functionalities based...... on silicon photonics. In particular we use nano-engineered silicon waveguides (nanowires) [1] enabling efficient phasematched four-wave mixing (FWM), cross-phase modulation (XPM) or self-phase modulation (SPM) for ultra-high-speed optical signal processing of ultra-high bit rate serial data signals. We show...

  13. Electronic structure and optical properties of AIN under high pressure

    International Nuclear Information System (INIS)

    Li Zetao; Dang Suihu; Li Chunxia

    2011-01-01

    We have calculated the electronic structure and optical properties of Wurtzite structure AIN under different high pressure with generalized gradient approximation (GGA) in this paper. The total energy, density of state, energy band structure and optical absorption and reflection properties under high pressure are calculated. By comparing the changes of the energy band structure, we obtained AIN phase transition pressure for 16.7 GPa, which is a direct band structure transforming to an indirect band structure. Meanwhile, according to the density of states distribution and energy band structure, we analyzed the optical properties of AIN under high-pressure, the results showed that the absorption spectra moved from low-energy to high-energy. (authors)

  14. Determination of energy band diagram and charge carrier mobility of white emitting polymer from optical, electrical and impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Sarjidan, M.A., E-mail: mohd.arif@um.edu.my; Mohd Mokhtar, H.A.; Abd Majid, W.H., E-mail: q3haliza@um.edu.my

    2015-03-15

    A single-layer white polymer light-emitting device (WPLED) has been fabricated using spin coating technique. The device was constructed as ITO/PEDOT:PSS(50 nm)/SPW-111(50 nm)/LiF(1 nm)/Al(100 nm). Indium tin oxide (ITO) and poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate (PEDOT:PSS) are used as the transparent anode. SPW-111 is fabricated as a white emissive layer and lithium fluoride (LiF) and aluminum (Al) are used as reflecting cathode. Energy band diagram of the device was estimated from a combination of ultraviolet–visible (UV–vis) and current–voltage (J–V) analyses. Charge carrier mobility (μ) of PLED was evaluated using negative differential susceptance (−ΔB) method from impedance spectroscopy (IS) analysis. The calculated μ of the SPW-111 device is in the magnitude of 10{sup −6} cm{sup 2}/V/s. - Highlights: • Single layer PLED has been fabricated with spin-coating technique and device performance has been evaluated. • Energy band diagram of the SPW-111 is estimated from optical and electrical analyses. • Charge carrier mobility of the SPW-111 materials is obtained by impedance spectroscopy.

  15. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    International Nuclear Information System (INIS)

    Haseroth, Helmut; Hora, Heinrich; Regensburg Inst. of Tech.

    1996-01-01

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10 11 C 4+ ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ''hot'' electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author)

  16. Physical mechanisms leading to high currents of highly charged ions in laser-driven ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Haseroth, Helmut [European Organization for Nuclear Research, Geneva (Switzerland); Hora, Heinrich [New South Wales Univ., Kensington, NSW (Australia)]|[Regensburg Inst. of Tech. (Germany). Anwenderzentrum

    1996-12-31

    Heavy ion sources for the big accelerators, for example, the LHC, require considerably more ions per pulse during a short time than the best developed classical ion source, the electron cyclotron resonance (ECR) provides; thus an alternative ion source is needed. This can be expected from laser-produced plasmas, where dramatically new types of ion generation have been observed. Experiments with rather modest lasers have confirmed operation with one million pulses of 1 Hz, and 10{sup 11} C{sup 4+} ions per pulse reached 2 GeV/u in the Dubna synchrotron. We review here the complexities of laser-plasma interactions to underline the unique and extraordinary possibilities that the laser ion source offers. The complexities are elaborated with respect to keV and MeV ion generation, nonlinear (ponderomotive) forces, self-focusing, resonances and ``hot`` electrons, parametric instabilities, double-layer effects, and the few ps stochastic pulsation (stuttering). Recent experiments with the laser ion source have been analyzed to distinguish between the ps and ns interaction, and it was discovered that one mechanism of highly charged ion generation is the electron impact ionization (EII) mechanism, similar to the ECR, but with so much higher plasma densities that the required very large number of ions per pulse are produced. (author).

  17. DC space-charge induced frequency up-shift in a quasi-optical gyrotron

    International Nuclear Information System (INIS)

    Alberti, S.; Tran, M.Q.; Tran, T.M.

    1990-10-01

    Recent experiments on a 100GHz quasi-optical gyrotron have shown that for a large resonator set-up the observed frequency up-shift between the starting current and a current of 10A corresponds to a shift of 4-5 longitudinal modes. In this Letter it is shown that the interpretation of this frequency up-shift should involve the current dependent electron beam voltage depression in the beam tunnel and the interaction region for both the single-mode and multi-mode time evolution codes. (author) 7 refs., 5 figs., 1 tab

  18. Optical High Harmonic Generation in C60

    Science.gov (United States)

    Zhang, Guoping

    2005-03-01

    C60 et al. Physical Review Letters Physical Review B High harmonic generation (HHG) requires a strong laser field, but in a relatively weak laser field is sufficient. Numerical results presented here show while its low order harmonics result from the laser field, its high order ones are mainly from the multiple excitations. Since high order harmonics directly correlate electronic transitions, the HHG spectrum accurately measures transition energies. Therefore, is not only a promising material for HHG, but may also present an opportunity to develop HHG into an electronic structure probing tool. References: G. P. Zhang, 91, 176801 (2003); G. P. Zhang and T. F. George, 68, 165410 (2003); P. B. Corkum, 71, 1994 (1993); G. P. Zhang and Thomas F. George, 93, 147401 (2004); H. Niikura ,ature 417, 917 (2002); ibid. 421, 826 (2003); Y. Mairesse ,cience 302, 1540 (2003); A. Baltuska ,ature 421, 611 (2003).

  19. Aberrations due to solenoid focusing of a multiply charged high-current ion beam

    CERN Document Server

    Grégoire, G; Lisi, N; Schnuriger, J C; Scrivens, R; Tambini, J

    2000-01-01

    At the output of a laser ion source, a high current of highly charged ions with a large range of charge states is available. The focusing of such a beam by magnetic elements causes a nonlinear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the three dimensional software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses. (5 refs).

  20. The longitudinal space charge problem in the high current linear proton accelerators

    International Nuclear Information System (INIS)

    Lustfeld, H.

    1984-01-01

    In a linear proton accelerator peak currents of 200 mA lead to high space charge densities and the resultant space charge forces reduce the effective focussing considerably. In particular the longitudinal focussing is affected. A new concept based on linear theory is proposed that restricts the influence of the space charge forces on the longitudinal focussing by increasing a, the mean transverse bunch radius, as a proportional(βγ)sup(3/8). This concept is compared with other concepts for the Alvarez (1 MeV - 100 MeV) and for the high energy part (100 MeV - 1100 MeV) of the SNQ linear accelerator. (orig.)

  1. The development of fluorides for high power laser optics

    Science.gov (United States)

    Ready, J. F.; Vora, H.

    1980-07-01

    The laser assisted thermonuclear fusion program has need for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride possesses a combination of optical properties which are of use. Single crystalline LiF is limited by low mechanical strength. The technique of press forging to increase the mechanical strength is investigated. LiF single crystals were press forged over the temperature range 300 - 600 deg C to produce fine grained polycrystalline material. Optical homogenity at 633, stress birefringence, scattering at 633, residual absorption over the spectral range 339 - 3800 nm, and laser damage thresholds for 1 ns, 1064 nm and 700 ps, 266 nm laser pulses are evaluated. Single crystals can be press forged without seriously degrading their optical properties. Yield strength in compression, proportional limit and fracture strength in 3 and 4 point bending, fracture energy, and threshold for microyield are discussed.

  2. High-energy nuclear optics of polarized particles

    CERN Document Server

    Baryshevsky, Vladimir G

    2012-01-01

    The various phenomena caused by refraction and diffraction of polarized elementary particles in matter have opened up a new research area in the particle physics: nuclear optics of polarized particles. Effects similar to the well-known optical phenomena such as birefringence and Faraday effects, exist also in particle physics, though the particle wavelength is much less than the distance between atoms of matter. Current knowledge of the quasi-optical effects, which exist for all particles in any wavelength range (and energies from low to extremely high), will enable us to investigate different properties of interacting particles (nuclei) in a new aspect. This pioneering book will provide detailed accounts of quasi-optical phenomena in the particle polarization, and will interest physicists and professionals in experimental particle physics.

  3. Highly Stretchable, Strain Sensing Hydrogel Optical Fibers.

    Science.gov (United States)

    Guo, Jingjing; Liu, Xinyue; Jiang, Nan; Yetisen, Ali K; Yuk, Hyunwoo; Yang, Changxi; Khademhosseini, Ali; Zhao, Xuanhe; Yun, Seok-Hyun

    2016-12-01

    A core-clad fiber made of elastic, tough hydrogels is highly stretchable while guiding light. Fluorescent dyes are easily doped into the hydrogel fiber by diffusion. When stretched, the transmission spectrum of the fiber is altered, enabling the strain to be measured and also its location. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Phase shift PWM with double two-switch bridge for high power capacitor charging

    International Nuclear Information System (INIS)

    Karandikar, U.S.; Singh, Yashpal; Thakurta, A.C.

    2013-01-01

    Pulse power supply systems working at higher voltage and high repetition rate demands for higher power from capacitor chargers. Capacitor charging requirement become more challenging in such cases. In pulse power circuits, energy storage capacitor should be charged to its desired voltage before the next switching occurs. It is discharged within a small time, delivering large pulse power. A capacitor charger has to work with wide load variation repeatedly. Many schemes are used for this purpose. The proposed scheme aims at reducing stresses on switches by reducing peak current and their evils. A high voltage power supply is designed for capacitor charging. The proposed scheme is based on a Phase-Shifted PWM without using any extra component to achieve soft switching. Indirect constant average current capacitor charging is achieved with a simple control scheme. A double two-switch bridge is proposed to enhance reliability. Power supply has been developed to charge a capacitor of 50 μF to 2.5 kV at 25 Hz. (author)

  5. High-frequency asymptotics of the emission spectrum of moving charged particles in classical electrodynamics

    International Nuclear Information System (INIS)

    Abbasov, I.I.; Bolotovskij, B.M.; Davydov, V.A.

    1986-01-01

    Electromagnetic radiation appears as a result of a charged particle movement in free space and also in heterogeneous and non-stationary medium. The radiation spectrum depends on the charged particle motion law, as well as on the law of the medium property chage in space and time. The asymptotics of radiation spectrum, i.e. behaviour of spectral intensity at high frequencies, is studied. It is shown that if a charged particle moves along smooth trajectory or if the change in the medium properties takes place accordng to the law described by a smooth function, the radiation spectrum at high frequencies decreases according to exponential law. Thus, radiation spectrum of a charged particle moving along a smooth trajectory in the medium with gradual heterogeneity and (or) instability is rapidly cut, starting from a certain frequency value. The smooth trajectory means that the charge moves according to the law r = r(t), where vector-function r(t) is continuous with all its derivatives. In much the same way the medium with gradual heterogeneities (or with gradual instability) is described by the functions which are continuous with all their derivatives of any order. The method permitting to determine the upper boundary of radiation spectra is presented

  6. Development of Discrete Power Supply with Charge Pump Method for High Powered Sonar System

    Directory of Open Access Journals (Sweden)

    Kristian Ismail

    2012-07-01

    Full Text Available Power supply is one of the electronic devices that can provide electric energy for electronic systems or other systems. There are several types of power supplies that can be applied depend on the requirement and functions. One example is the use of power supply for sonar systems. Sonar system is a device which can be used to detect a target under water. The sonar system is an electronic circuit that requires a power supply with specific characteristics when the sonar functions as a transmitter and a receiver in the specific span time (when on and the specific lag time (when off. This paper discusses the design of power supply for high-powered sonar systems with discrete methods in which high power supply is only applied when the acoustic waves radiated under water. Charge pump was used to get the appropriate output voltage from lower input voltage. Charge pump utilized a combination of series and parallel connections of capacitors. The working mode of this power supply used the lag time as the calculation of time to charge charge pump capacitors in parallel while the span time was used for the calculation of discharging the charge pump capacitors in series.

  7. Production of highly charged ion beams from electron cyclotron resonance ion sources (invited)

    International Nuclear Information System (INIS)

    Xie, Z.Q.

    1998-01-01

    Electron cyclotron resonance ion source (ECRIS) development has progressed with multiple-frequency plasma heating, higher mirror magnetic fields, and better technique to provide extra cold electrons. Such techniques greatly enhance the production of highly charged ions from ECRISs. So far at continuous wave (CW) mode operation, up to 300 eμA of O 7+ and 1.15 emA of O 6+ , more than 100 eμA of intermediate heavy ions for charge states up to Ar 13+ , Ca 13+ , Fe 13+ , Co 14+ , and Kr 18+ , and tens of eμA of heavy ions with charge states to Kr 26+ , Xe 28+ , Au 35+ , Bi 34+ , and U 34+ were produced from ECRISs. At an intensity of at least 1 eμA, the maximum charge state available for the heavy ions are Xe 36+ , Au 46+ , Bi 47+ , and U 48+ . An order of magnitude enhancement for fully stripped argon ions (I≥60enA) were also achieved. This article will review the ECR ion source progress and discuss key requirement for ECRISs to produce the highly charged ion beams. copyright 1998 American Institute of Physics

  8. EBIT spectroscopy of highly charged heavy ions relevant to hot plasmas

    Science.gov (United States)

    Nakamura, Nobuyuki

    2013-05-01

    An electron beam ion trap (EBIT) is a versatile device for studying highly charged ions. We have been using two types of EBITs for the spectroscopic studies of highly charged ions. One is a high-energy device called the Tokyo-EBIT, and another is a compact low-energy device called CoBIT. Complementary use of them enables us to obtain spectroscopic data for ions over a wide charge-state range interacting with electrons over a wide energy range. In this talk, we present EBIT spectra of highly charged ions for tungsten, iron, bismuth, etc., which are relevant to hot plasmas. Tungsten is considered to be the main impurity in the ITER (the next generation nuclear fusion reactor) plasma, and thus its emission lines are important for diagnosing and controlling the ITER plasma. We have observed many previously unreported lines to supply the lack of spectroscopic data of tungsten ions. Iron is one of the main components of the solar corona, and its spectra are used to diagnose temperature, density, etc. The diagnostics is usually done by comparing observed spectra with model calculations. An EBIT can provide spectra under a well-defined condition; they are thus useful to test the model calculations. Laser-produced bismuth plasma is one of the candidates for a soft x-ray source in the water window region. An EBIT has a narrow charge state distribution; it is thus useful to disentangle the spectra of laser-produced plasma containing ions with a wide charge-state range. Performed with the support and under the auspices of the NIFS Collaboration Research program (NIFS09KOAJ003) and JSPS KAKENHI Number 23246165, and partly supported by the JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics.

  9. Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

    Science.gov (United States)

    Higuchi, Yoshinori; Nelson, Gregory A.; Vazquez, Marcelo; Laskowitz, Daniel T.; Slater, James M.; Pearlstein, Robert D.

    2002-01-01

    Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. METHODS: Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. ROTAROD TEST: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. OPEN FIELD TEST: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. MORRIS WATER MAZE: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. CONCLUSIONS: These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the CNS. ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process.

  10. Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

    International Nuclear Information System (INIS)

    Higuchi, Yoshinori; Nelson, G.A.; Slater, J.M.; Pearlstein, R.D.; Laskowitz, D.T.

    2002-01-01

    Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. Rotarod test: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. Open field test: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. Morris water maze: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the central nervous system (CNS). ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process. (author)

  11. Apolipoprotein E expression and behavioral toxicity of high charge, high energy (HZE) particle radiation

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Yoshinori; Nelson, G.A.; Slater, J.M.; Pearlstein, R.D. [Loma Linda Univ., CA (United States). Medical Center; Vazquez, M. [Brookhaven National Lab., Upton, NY (United States); Laskowitz, D.T. [Duke Univ., Durham, NC (United States). Medical Center

    2002-12-01

    Apolipoprotein E (apoE) is a lipid binding protein that plays an important role in tissue repair following brain injury. In the present studies, we have investigated whether apoE affects the behavioral toxicity of high charge, high energy (HZE) particle radiation. Sixteen male apoE knockout (KO) mice and sixteen genetically matched wild-type (WT) C57BL mice were used in this experiment. Half of the KO and half of the WT animals were irradiated with 600 MeV/amu iron particles (2 Gy whole body). The effect of irradiation on motor coordination and stamina (Rotarod test), exploratory behavior (open field test), and spatial working and reference memory (Morris water maze) was assessed. Rotarod test: Performance was adversely affected by radiation exposure in both KO and WT groups at 30 d after irradiation. By 60 d after radiation, the radiation effect was lost in WT, but still apparent in irradiated KO mice. Open field test: Radiation reduced open field exploratory activity 14, 28, 56, 84, and 168 d after irradiation of KO mice, but had no effect on WT mice. Morris water maze: Radiation adversely affected spatial working memory in the KO mice, but had no discernible effect in the WT mice as assessed 180 d after irradiation. In contrast, irradiated WT mice showed marked impairment of spatial reference memory in comparison to non-irradiated mice, while no effect of radiation was observed in KO mice. These studies show that apoE expression influences the behavioral toxicity of HZE particle radiation and suggest that apoE plays a role in the repair/recovery from radiation injury of the central nervous system (CNS). ApoE deficiency may exacerbate the previously reported effects of HZE particle radiation in accelerating the brain aging process. (author)

  12. Fast optical detecting media based on semiconductor nanostructures for recording images obtained using charges of free photocarriers

    International Nuclear Information System (INIS)

    Kasherininov, P. G.; Tomasov, A. A.; Beregulin, E. V.

    2011-01-01

    Available published data on the properties of optical recording media based on semiconductor structures are reviewed. The principles of operation, structure, parameters, and the range of application for optical recording media based on MIS structures formed of photorefractive crystals with a thick layer of insulator and MIS structures with a liquid crystal as the insulator (the MIS LC modulators), as well as the effect of optical bistability in semiconductor structures (semiconductor MIS structures with nanodimensionally thin insulator (TI) layer, M(TI)S nanostructures). Special attention is paid to recording media based on the M(TI)S nanostructures promising for fast processing of highly informative images and to fabrication of optoelectronic correlators of images for noncoherent light.

  13. Classical/quantum correspondence in state selective charge transfer and excitation reactions involving highly charged ions and hydrogen

    International Nuclear Information System (INIS)

    Purkait, M

    2009-01-01

    State selective charge transfer and excitation cross sections for collisions of Ne q+ (q = 1-10) with atomic hydrogen are calculated within the framework of Classical Trajectory Monte Carlo (CTMC) method and Boundary Corrected Continuum Intermediate State (BCCIS) approximation.

  14. Initial observations of high-charge, low-emittance electron beams at HIBAF (High Brightness Accelerator FEL)

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H.; Feldman, R.B.; Carsten, B.E.; Feldman, D.W.; Sheffield, R.L.; Stein, W.E.; Johnson, W.J.; Thode, L.E.; Bender, S.C.; Busch, G.E.

    1990-01-01

    We report our initial measurements of bright (high-charge, low-emittance) electron beams generated at the Los Alamos High Brightness Accelerator FEL (HIBAF) Facility. Normalized emittance values of less than 50 {pi} mm-mrad for charges ranging from 0.7 to 8.7 nC were obtained for single micropulses at a y-waist and at an energy of 14.7 MeV. These measurements were part of the commissioning campaign on the HIBAF photoelectric injector. Macropulse measurements have also been performed and are compared with PARMELA simulations. 5 refs., 8 figs., 3 tabs.

  15. Secondary-electron yield from Au induced by highly charged Ta ions

    Czech Academy of Sciences Publication Activity Database

    Krása, Josef; Láska, Leoš; Stöckli, M. P.; Fry, D.

    2001-01-01

    Roč. 173, - (2001), s. 281-286 ISSN 0168-583X R&D Projects: GA AV ČR IAA1010819 Institutional research plan: CEZ:AV0Z1010914 Keywords : highly charged ion-surface interaction * ion-induced electron emission * angle impact effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.041, year: 2001

  16. Simple heuristic derivation of some charge-transfer probabilities at asymptotically high incident velocities

    International Nuclear Information System (INIS)

    Spruch, L.; Shakeshaft, R.

    1984-01-01

    For asymptotically high incident velocities we provide simple, heuristic, almost classical, derivations of the cross section for forward charge transfer, and of the ratio of the cross section for capture to the elastic-scattering cross section for the projectile scattered through an angle close to π/3

  17. Analysis and design of a charge pump circuit for high output current applications

    NARCIS (Netherlands)

    van Steenwijk, Gijs; van Steenwijk, Gijs; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans

    1993-01-01

    A charge pump circuit has been developed that can deliver high currents even for a system supply voltage of 3 V. The circuit consists of capacitances, connected by MOS switches. The influence of the on-resistance of the switches on the circuit's output resistance has been analysed. The switches are

  18. Spectroscopy of highly charged tungsten ions with Electron Beam Ion Traps

    International Nuclear Information System (INIS)

    Sakaue, Hiroyuki A.; Kato, Daiji; Morita, Shigeru; Murakami, Izumi; Yamamoto, Norimasa; Ohashi, Hayato; Yatsurugi, Junji; Nakamura, Nobuyuki

    2013-01-01

    We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra is investigated of electron energies from 490 to 1440 eV. Previously unreported lines are presented in the EUV range, and some of them are identified by comparing the wavelengths with theoretical calculations. (author)

  19. EUV spectrum of highly charged tungsten ions in electron beam ion trap

    International Nuclear Information System (INIS)

    Sakaue, H.A.; Kato, D.; Murakami, I.; Nakamura, N.

    2016-01-01

    We present spectra of highly charged tungsten ions in the extreme ultra-violet (EUV) by using electron beam ion traps. The electron energy dependence of spectra was investigated for electron energy from 540 to 1370 eV. Previously unreported lines were presented in the EUV range, and comparing the wavelengths with theoretical calculations identified them. (author)

  20. Techniques and mechanisms applied in electron cyclotron resonance sources for highly charged ions

    NARCIS (Netherlands)

    Drentje, AG

    Electron cyclotron resonance ion sources are delivering beams of highly charged ions for a wide range of applications in many laboratories. For more than two decades, the development of these ion sources has been to a large extent an intuitive and experimental enterprise. Much effort has been spent

  1. Fundamental processes determining the highly charged ion production in ECR ion sources

    International Nuclear Information System (INIS)

    Shirkov, G.D.

    1992-01-01

    The ion confinement and loss conditions in the open magnetic traps have been analyzed in this article. In EGRIS the the ions are confined in the negative potential well. The simultaneous application of ion cooling and pulse regime is proposed for pulse injection of highly charged ions in heavy ion accelerators and storage rings. 14 refs.; 3 figs

  2. Prospects for Parity Non-conservation Experiments with Highly Charged Heavy Ions

    OpenAIRE

    Maul, M.; Schäfer, A.; Greiner, W.; Indelicato, P.

    1996-01-01

    We discuss the prospects for parity non-conservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with two to five electrons are calculated. We investigate two-photon-transitions and the possibility to observe interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  3. Prospects for parity-nonconservation experiments with highly charged heavy ions

    OpenAIRE

    Maul, Martin; Schäfer, Andreas; Greiner, Walter; Indelicato, Paul

    2006-01-01

    We discuss the prospects for parity-nonconservation experiments with highly charged heavy ions. Energy levels and parity mixing for heavy ions with 2–5 electrons are calculated. We investigate two-photon transitions and the possibility of observing interference effects between weak-matrix elements and Stark matrix elements for periodic electric field configurations.

  4. Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

    International Nuclear Information System (INIS)

    Radeka, V.; Rescia, S.; Rehn, L.A.; Manfredi, P.F.; Speziali, V.

    1991-11-01

    The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFET) suggest that a monolithic preamplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described

  5. Nanometer-size surface modification produced by single, low energy, highly charged ions

    International Nuclear Information System (INIS)

    Stockli, M.P.

    1994-01-01

    Atomically flat surfaces of insulators have been bombarded with low energy, highly charged ions to search for nanometer-size surface modifications. It is expected that the high electron deficiency of highly charged ions will capture and/or remove many of the insulator's localized electrons when impacting on an insulating surface. The resulting local electron deficiency is expected to locally disintegrate the insulator through a open-quotes Coulomb explosionclose quotes forming nanometer-size craters. Xe ions with charge states between 10+ and 45+ and kinetic energies between 0 and 10 keV/q were obtained from the KSU-CRYEBIS, a CRYogenic Electron Beam Ion Source and directed onto various insulating materials. Mica was favored as target material as atomically flat surfaces can be obtained reliably through cleaving. However, the authors observations with an atomic force microscope have shown that mica tends to defoliate locally rather than disintegrate, most likely due to the small binding forces between adjacent layers. So far the authors measurements indicate that each ion produces one blister if the charge state is sufficiently high. The blistering does not seem to depend very much on the kinetic energy of the ions

  6. Enhanced intersystem crossing via a high energy charge transfer state in a perylenediimide-perylenemonoimide dyad

    NARCIS (Netherlands)

    Veldman, D.; Chopin-Cado, S.M.A; Meskers, S.C.J.; Janssen, R.A.J.

    2008-01-01

    The electronic relaxation processes of a photoexcited linear perylenediimide-perylenemonoimide (PDI-PMI) acceptor-donor dyad were studied. PDI-PMI serves as a model compound for donor-acceptor systems in photovoltaic devices and has been designed to have a high-energy PDI--PMI + charge transfer (CT)

  7. Hall mobility of free charge carriers in highly compensated p-Germanium

    International Nuclear Information System (INIS)

    Gavrilyuk, V.Yi.; Kirnas, Yi.G.; Balakyin, V.D.

    2000-01-01

    Hall mobility of free charge carriers in initial detectors Ge (Ga) is studied. It is established that an increase in the compensation factor results in the enlargement of Hall mobility in germanium highly compensated by introduction of Li ions during their drift in an electrical field

  8. Optical design of high power excimer laser system

    International Nuclear Information System (INIS)

    Zhang Yongsheng; Zhao Jun; Ma Lianying; Yi Aiping; Liu Jingru

    2011-01-01

    Image relay and angular multiplexing,which should be considered together in the design of high power excimer laser system, is reviewed. It's important to select proper illumination setup and laser beam shaping techniques. Given the complex and special angular multiplexing scheme in high power excimer laser systems, some detailed conceptual layout schemes are given in the paper. After a brief description of lens array and reflective telescope objective, which combine the incoming beams to a common focus, a new schematic layout which uses the final targeting optics and one optical delay line array, to realize multiplexing and de-multiplexing simultaneously is first proposed in the paper. (authors)

  9. High-speed photodetectors in optical communication system

    Science.gov (United States)

    Zhao, Zeping; Liu, Jianguo; Liu, Yu; Zhu, Ninghua

    2017-12-01

    This paper presents a review and discussion for high-speed photodetectors and their applications on optical communications and microwave photonics. A detailed and comprehensive demonstration of high-speed photodetectors from development history, research hotspots to packaging technologies is provided to the best of our knowledge. A few typical applications based on photodetectors are also illustrated, such as free-space optical communications, radio over fiber and millimeter terahertz signal generation systems. Project supported by the Preeminence Youth Fund of China (No. 61625504).

  10. Charge transfer and excitation in high-energy ion-atom collisions

    International Nuclear Information System (INIS)

    Schlachter, A.S.; Berkner, K.H.; McDonald, R.J.

    1986-11-01

    Coincidence measurements of charge transfer and simultaneous projectile electron excitation provide insight into correlated two-electron processes in energetic ion-atom collisions. Projectile excitation and electron capture can occur simultaneously in a collision of a highly charged ion with a target atom; this process is called resonant transfer and excitation (RTE). The intermediate excited state which is thus formed can subsequently decay by photon emission or by Auger-electron emission. Results are shown for RTE in both the K shell of Ca ions and the L shell of Nb ions, for simultaneous projectile electron loss and excitation, and for the effect of RTE on electron capture

  11. Charged Particle Production in High Q2 Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-01-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, $\\xp$, of charged final state hadrons are measured in deep-inelastic $\\ep$ scattering at high $Q^2$ in the Breit frame of reference. The analysis covers the range of photon virtuality $100 < Q^2 < 20 000 \\GeV^{2}$. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher $Q^{2}$ and to the full range of $\\xp$. The results are compared with $e^+e^-$ annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process.

  12. Charged particle production in high Q deep-inelastic scattering at HERA

    Science.gov (United States)

    H1 Collaboration; Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Avila, K. B. Cantun; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Trevino, A. Vargas; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-10-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, x, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q in the Breit frame of reference. The analysis covers the range of photon virtuality 100

  13. Charged particle production in high Q2 deep-inelastic scattering at HERA

    Science.gov (United States)

    Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Avila, K. B. Cantun; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Trevino, A. Vargas; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; H1 Collaboration

    2007-10-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, xp, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q2 in the Breit frame of reference. The analysis covers the range of photon virtuality 100

  14. Optically active charge transfer in hybrids of Alq3 nanoparticles and MoS2 monolayer

    Science.gov (United States)

    Ghimire, Ganesh; Dhakal, Krishna P.; Neupane, Guru P.; Jo, Seong Gi; Kim, Hyun; Seo, Changwon; Lee, Young Hee; Joo, Jinsoo; Kim, Jeongyong

    2017-05-01

    Organic/inorganic hybrid structures have been widely studied because of their enhanced physical and chemical properties. Monolayers of transition metal dichalcogenides (1L-TMDs) and organic nanoparticles can provide a hybridization configuration between zero- and two-dimensional systems with the advantages of convenient preparation and strong interface interaction. Here, we present such a hybrid system made by dispersing π-conjugated organic (tris (8-hydroxyquinoline) aluminum(III)) (Alq3) nanoparticles (NPs) on 1L-MoS2. Hybrids of Alq3 NP/1L-MoS2 exhibited a two-fold increase in the photoluminescence of Alq3 NPs on 1L-MoS2 and the n-doping effect of 1L-MoS2, and these spectral and electronic modifications were attributed to the charge transfer between Alq3 NPs and 1L-MoS2. Our results suggested that a hybrid of organic NPs/1L-TMD can offer a convenient platform to study the interface interactions between organic and inorganic nano objects and to engineer optoelectronic devices with enhanced performance.

  15. Solution processable semiconductor thin films: Correlation between morphological, structural, optical and charge transport properties

    Science.gov (United States)

    Isik, Dilek

    This Ph.D. thesis is a result of multidisciplinary research bringing together fundamental concepts in thin film engineering, materials science, materials processing and characterization, electrochemistry, microfabrication, and device physics. Experiments were conducted by tackling scientific problems in the field of thin films and interfaces, with the aim to correlate the morphology, crystalline structure, electronic structure of thin films with the functional properties of the films and the performances of electronic devices based thereon. Furthermore, novel strategies based on interfacial phenomena at electrolyte/thin film interfaces were explored and exploited to control the electrical conductivity of the thin films. Three main chemical systems were the object of the studies performed during this Ph.D., two types of organic semiconductors (azomethine-based oligomers and polymers and soluble pentacene derivatives) and one metal oxide semiconductor (tungsten trioxide, WO3). To explore the morphological properties of the thin films, atomic force microscopy was employed. The morphological properties were further investigated by hyperspectral fluorescence microscopy and tentatively correlated to the charge transport properties of the films. X-ray diffraction (Grazing incidence XRD, GIXRD) was used to investigate the crystallinity of the film and the effect of the heat treatment on such crystallinity, as well as to understand the molecular arrangement of the organic molecules in the thin film. The charge transport properties of the films were evaluated in thin film transistor configuration. For electrolyte gated thin film transistors, time dependent transient measurements were conducted, in parallel to more conventional transistor characterizations, to explore the specific effects played on the gating by the anion and cation constituting the electrolyte. The capacitances of the electrical double layers at the electrolyte/WO3 interface were obtained from

  16. The application of the signal flow graph method to charged-particle optics - the formula derivation of a three-sector isotope separator

    International Nuclear Information System (INIS)

    Lu Hongyou; Zhao Zhiyong; Sun Quinren

    1987-01-01

    A brief introduction of the Signal Flow Graph (SFG) method is given. The application of it to charged-particle optics (CPO) is described. The method has the advantages of simplicity, visualisation and computerisation. An example of the application of SFG is given for the design of a three-sector electromagnetic isotope separator. (orig.)

  17. Process techniques of charge transfer time reduction for high speed CMOS image sensors

    International Nuclear Information System (INIS)

    Cao Zhongxiang; Li Quanliang; Han Ye; Qin Qi; Feng Peng; Liu Liyuan; Wu Nanjian

    2014-01-01

    This paper proposes pixel process techniques to reduce the charge transfer time in high speed CMOS image sensors. These techniques increase the lateral conductivity of the photo-generated carriers in a pinned photodiode (PPD) and the voltage difference between the PPD and the floating diffusion (FD) node by controlling and optimizing the N doping concentration in the PPD and the threshold voltage of the reset transistor, respectively. The techniques shorten the charge transfer time from the PPD diode to the FD node effectively. The proposed process techniques do not need extra masks and do not cause harm to the fill factor. A sub array of 32 × 64 pixels was designed and implemented in the 0.18 μm CIS process with five implantation conditions splitting the N region in the PPD. The simulation and measured results demonstrate that the charge transfer time can be decreased by using the proposed techniques. Comparing the charge transfer time of the pixel with the different implantation conditions of the N region, the charge transfer time of 0.32 μs is achieved and 31% of image lag was reduced by using the proposed process techniques. (semiconductor devices)

  18. Ionization and fragmentation of water clusters by fast highly charged ions

    International Nuclear Information System (INIS)

    Adoui, L; Cassimi, A; Gervais, B; Grandin, J-P; Guillaume, L; Maisonny, R; Legendre, S; Tarisien, M; Lopez-Tarifa, P; Alcami, M; Martin, F; Politis, M-F; Penhoat, M-A Herve du; Vuilleumier, R; Gaigeot, M-P; Tavernelli, I

    2009-01-01

    We study the dissociative ionization of water clusters by impact of 12 MeV/u Ni 25+ ions. Cold target recoil ion momentum spectroscopy (COLTRIMS) is used to obtain information about stability, energetics and charge mobility of the ionized water clusters. An unusual stability of the H 9 O + 4 ion is observed, which could be the signature of the so-called Eigen structure in gas-phase water clusters. From the analysis of coincidences between charged fragments, we conclude that charge mobility is very high and is responsible for the formation of protonated water clusters, (H 2 O) n H + , that dominate the mass spectrum. These results are supported by Car-Parrinello molecular dynamics and time-dependent density functional theory simulations, which also reveal the mechanisms of such mobility.

  19. Demonstration of cathode emittance dominated high bunch charge beams in a DC gun-based photoinjector

    Energy Technology Data Exchange (ETDEWEB)

    Gulliford, Colwyn, E-mail: cg248@cornell.edu; Bartnik, Adam, E-mail: acb20@cornell.edu; Bazarov, Ivan; Dunham, Bruce; Cultrera, Luca [CLASSE, Cornell University, 161 Synchrotron Drive Ithaca, New York 14853-8001 (United States)

    2015-03-02

    We present the results of transverse emittance and longitudinal current profile measurements of high bunch charge (≥100 pC) beams produced in the DC gun-based Cornell energy recovery linac photoinjector. In particular, we show that the cathode thermal and core beam emittances dominate the final 95% and core emittances measured at 9–9.5 MeV. Additionally, we demonstrate excellent agreement between optimized 3D space charge simulations and measurement, and show that the quality of the transverse laser distribution limits the optimal simulated and measured emittances. These results, previously thought achievable only with RF guns, demonstrate that DC gun based photoinjectors are capable of delivering beams with sufficient single bunch charge and beam quality suitable for many current and next generation accelerator projects such as Energy Recovery Linacs and Free Electron Lasers.

  20. Charge- and transverse momentum dependence of correlations in proton-proton interactions at very high energies

    International Nuclear Information System (INIS)

    Hofmann, W.

    1977-07-01

    The charge- and momentum dependence of correlations between secondaries emitted in pp-collisions at √s = 52 GeV was investigated using the Split-Field-Magnet spectrometer at the CERN Intersecting Storage Rings (ISR). For nondiffractive inelastic events the central particle production is characterized by local conservation of charge and global compensation of transverse momenta. Strong short range correlations due to cluster decay and Bose-Einstein effects are observed. A consistent description of the correlations is given in the framework of cluster models. Local conservation of charge is also detected in events, where a particle of high transverse momentum is produced. The observations are in good agreement with the predictions of a simple quark parton model. (orig.) [de

  1. High-energy behavior of the charge-transfer cross section in the eikonal approximation

    International Nuclear Information System (INIS)

    Dewangan, D.P.

    1982-01-01

    In the now popular version of the eikonal theory of charge transfer, the eikonal wave function does not satisfy the proper boundary conditions and the charge-transfer amplitude is uncertain by an undefined phase factor. The inclusion of the internuclear potential in a consistent way, in the eikonal theory overcomes theses difficulties. However, it also changes the high-energy asymptotic form of proton-hydrogen charge-transfer cross section from sigma/sub eik/ approx.(23/48) sigma/sub BK/ by a small amount to sigma/sub G/approx.(20.109/48)sigma/sub BK/ where sigma/sub BK/ is the Brinkman-Kramers cross section

  2. Beam transport optics for high-power laser systems

    International Nuclear Information System (INIS)

    Taylor, J.R.

    1995-01-01

    Beam transport optics receive output energy from the laser cavity and deliver it to the work site. Depending on the application, this may require a few simple elements or large complex systems. Collection of the laser energy depends on the spatial and temporal energy distribution as well as the wavelength and polarization of the laser cavity and output coupler. Transport optics can perform a variety of functions, including beam formatting, frequency doubling, and distribution to one or more work sites while maintaining or even improving the beam quality. The beam may be delivered to work sites as focused spots or images, projected to distant targets, or propagated through various media for sensing or photochemical processing. Design may involve optical modeling of the system, including diffraction effects and thermal management. A Gaussian beam profile is often used for convenience in modeling. When deviations from this ideal profile need to be considered, it is necessary to characterize the laser beam in detail. Design of the transport system requires understanding of the interaction of the laser energy with optical materials and components. Practical considerations include mounting the optics without stress and with the stability suitable for the intended application. Requirements for beam direction, stability, size, shape, and quality dictate the design approach for each specific situation. Attention also must be given to reliability, environmental, and commercial requirements. Damage to optics in high-power laser systems is a common concern. Environmental problems such as atmospheric turbulence, contamination by dust or vapor from the work site or other sources, or absorption of water vapor can directly degrade beam quality. Other potentially significant optical performance effects may result from instability and aging of the optics, temperature, humidity, pressure, transmitted vibration, and contamination from the work site or other sources

  3. Characterizing the optical properties of human brain tissue with high numerical aperture optical coherence tomography.

    Science.gov (United States)

    Wang, Hui; Magnain, Caroline; Sakadžić, Sava; Fischl, Bruce; Boas, David A

    2017-12-01

    Quantification of tissue optical properties with optical coherence tomography (OCT) has proven to be useful in evaluating structural characteristics and pathological changes. Previous studies primarily used an exponential model to analyze low numerical aperture (NA) OCT measurements and obtain the total attenuation coefficient for biological tissue. In this study, we develop a systematic method that includes the confocal parameter for modeling the depth profiles of high NA OCT, when the confocal parameter cannot be ignored. This approach enables us to quantify tissue optical properties with higher lateral resolution. The model parameter predictions for the scattering coefficients were tested with calibrated microsphere phantoms. The application of the model to human brain tissue demonstrates that the scattering and back-scattering coefficients each provide unique information, allowing us to differentially identify laminar structures in primary visual cortex and distinguish various nuclei in the midbrain. The combination of the two optical properties greatly enhances the power of OCT to distinguish intricate structures in the human brain beyond what is achievable with measured OCT intensity information alone, and therefore has the potential to enable objective evaluation of normal brain structure as well as pathological conditions in brain diseases. These results represent a promising step for enabling the quantification of tissue optical properties from high NA OCT.

  4. High speed manyframe optical methods for plasma diagnostics

    International Nuclear Information System (INIS)

    Erokhin, A.A.; Shikanov, A.S.; Sklizkov, G.V.; Zakharenkov, Yu.A.; Zorev, N.N.

    1979-01-01

    A complex of active optical plasma and strong ionized shock wave diagnostics is described. The complex consisted of a specially developed high speed manyframe systems of shadow, schlieren and interferometric photography. The comparison of results obtained by a simultaneous registration of investigated object by means of different optical methods allowed us to determine optimal employment range for the methods. The sensitivity, temporal and space resolution of each optical method under conditions of high probe radiation refraction are discussed. The application boundaries of these methods for ionized shock wave investigation were found to depend on the shock wave front width. The methods described were used for the study of laser-produced plasma phenomena, occuring in the experiments on powerful nine-channel laser installation ''Kalmar''. (author)

  5. Workshop on high heat load x-ray optics

    International Nuclear Information System (INIS)

    1990-01-01

    A workshop on ''High Heat Load X-Ray Optics'' was held at Argonne National Laboratory on August 3--5, 1989. The object of this workshop was to discuss recent advances in the art of cooling x-ray optics subject to high heat loads from synchrotron beams. The cooling of the first optical element in the intense photon beams that will be produced in the next generation of synchrotron sources is recognized as one of the major challenges that must be faced before one will be able to use these very intense beams in future synchrotron experiments. Considerable advances have been made in this art during the last few years, but much work remains to be done before the heating problem can be said to be completely solved. Special emphasis was placed on recent cooling experiments and detailed ''finite element'' and ''finite difference'' calculations comparing experiment with theory and extending theory to optimize performance

  6. Band structure and optical properties of highly anisotropic LiBa2[B10O16(OH)3] decaborate crystal

    International Nuclear Information System (INIS)

    Smok, P.; Kityk, I.V.; Berdowski, J.

    2003-01-01

    The band structure (BS), charge density distribution and linear-optical properties of the anisotropic crystal LiBa 2 [B 10 O 16 (OH) 3 ] (LBBOH) are calculated using a self-consistent norm-conserving pseudopotential method within the framework of the local-density approximation theory. A high anisotropy of the band energy gap (4.22 eV for the E parallel b, 4.46 eV for the E parallel c) and giant birefringence (up to 0.20) are found. Comparison of the theoretically calculated and the experimentally measured polarised spectra of the imaginary part of the dielectric susceptibility ε 2 shows a good agreement. The anisotropy of the charge density distribution, BS dispersion and of the optical spectra originate from anisotropy between the 2p z B-2p z O and 2p y,x B-2p y,y O bonding orbitals. The observed anisotropy in the LBBOH is principally different from that of β-BaB 2 O 4 (BBO) single crystals. In the LBBOH single crystals the anisotropy of optical and charge density distribution is caused by different projection of the orbitals originating from particular borate clusters on the particular crystallographic axes, contrary to the BBO, where the anisotropy is caused prevailingly by a different local site symmetry of oxygen within the borate planes. The observed anisotropy is analysed in terms of the band energy dispersion and space charge density distribution

  7. Measurement of the topological charge and index of vortex vector optical fields with a space-variant half-wave plate.

    Science.gov (United States)

    Liu, Gui-Geng; Wang, Ke; Lee, Yun-Han; Wang, Dan; Li, Ping-Ping; Gou, Fangwang; Li, Yongnan; Tu, Chenghou; Wu, Shin-Tson; Wang, Hui-Tian

    2018-02-15

    Vortex vector optical fields (VVOFs) refer to a kind of vector optical field with an azimuth-variant polarization and a helical phase, simultaneously. Such a VVOF is defined by the topological index of the polarization singularity and the topological charge of the phase vortex. We present a simple method to measure the topological charge and index of VVOFs by using a space-variant half-wave plate (SV-HWP). The geometric phase grating of the SV-HWP diffracts a VVOF into ±1 orders with orthogonally left- and right-handed circular polarizations. By inserting a polarizer behind the SV-HWP, the two circular polarization states project into the linear polarization and then interfere with each other to form the interference pattern, which enables the direct measurement of the topological charge and index of VVOFs.

  8. High temperature cathodic charging of hydrogen in zirconium alloys and iron and nickel base alloys

    International Nuclear Information System (INIS)

    John, J.T.; De, P.K.; Gadiyar, H.S.

    1990-01-01

    These investigations lead to the development of a new technique for charging hydrogen into metals and alloys. In this technique a mixture of sulfates and bisulfates of sodium and potassium is kept saturated with water at 250-300degC in an open pyrex glass beaker and electrolysed using platinum anode and the material to be charged as the cathode. Most of the studies were carried out on Zr alloys. It is shown that because of the high hydrogen flux available at the surface and the high diffusivity of hydrogen in metals at these temperatures the materials pick up hydrogen faster and more uniformly than the conventional electrolytic charging at room temperature and high temperature autoclaving in LiOH solutions. Chemical analysis, metallographic examination and XRD studies confirm this. This technique has been used to charge hydrogen into many iron and nickel base austentic alloys, which are very resistant to hydrogen pick up and to H-embrittlement. Since this involved a novel method of electrolysing water, the hydrogen/deuterium isotopic ratio has been studied. At this temperatures the D/H ratio in the evolved hydrogen gas was found to be closer to the value in the liquid water, which means a smaller separation factor. This confirm the earlier observation that separation factor decreases with increase of temperature. (author). 16 refs., 21 fi gs., 6 tabs

  9. Super TOF secondary ion mass spectroscopy using very highly charged primary ions up to Th70+

    International Nuclear Information System (INIS)

    Briere, M.A.; Schenkel, T.; Schneider, D.

    1995-01-01

    The LLNL Electron Beam Ion Trap (EBIT) has made low emittance beams of slow highly charged ions available for ion-solid interaction studies. Such interactions feature the dominance of electronic over collisional effects, and the shock waves generated by the ionized target atoms can desorb large numbers of large molecular species from the surface. This paper presents the first systematic study of the sputtering process due to the incidence of slow very highly charged ions; Th 70+ ions are extracted from EBIT at 7 keV * q and directed onto thin SiO 2 films on Si. Results suggest secondary ion yields of up to 25 per incident ion for Th 70+ (secondary ion yield is increased over that for singly or moderately charged ions). Correlations of the negative, positive, and negative cluster ion yields show promise for application of highly charged ion induced sputtering for enhanced sensitivity and quantitative (absolute) SIMS analysis of deep submicron scale surface layers and polymeric and biomolecular material analysis

  10. Active x-ray optics for high resolution space telescopes

    Science.gov (United States)

    Doel, Peter; Atkins, Carolyn; Brooks, D.; Feldman, Charlotte; Willingale, Richard; Button, Tim; Rodriguez Sanmartin, Daniel; Meggs, Carl; James, Ady; Willis, Graham; Smith, Andy

    2017-11-01

    The Smart X-ray Optics (SXO) Basic Technology project started in April 2006 and will end in October 2010. The aim is to develop new technologies in the field of X-ray focusing, in particular the application of active and adaptive optics. While very major advances have been made in active/adaptive astronomical optics for visible light, little was previously achieved for X-ray optics where the technological challenges differ because of the much shorter wavelengths involved. The field of X-ray astronomy has been characterized by the development and launch of ever larger observatories with the culmination in the European Space Agency's XMM-Newton and NASA's Chandra missions which are currently operational. XMM-Newton uses a multi-nested structure to provide modest angular resolution ( 10 arcsec) but large effective area, while Chandra sacrifices effective area to achieve the optical stability necessary to provide sub-arc second resolution. Currently the European Space Agency (ESA) is engaged in studies of the next generation of X-ray space observatories, with the aim of producing telescopes with increased sensitivity and resolution. To achieve these aims several telescopes have been proposed, for example ESA and NASA's combined International X-ray Observatory (IXO), aimed at spectroscopy, and NASA's Generation-X. In the field of X-ray astronomy sub 0.2 arcsecond resolution with high efficiency would be very exciting. Such resolution is unlikely to be achieved by anything other than an active system. The benefits of a such a high resolution would be important for a range of astrophysics subjects, for example the potential angular resolution offered by active X-ray optics could provide unprecedented structural imaging detail of the Solar Wind bowshock interaction of comets, planets and similar objects and auroral phenomena throughout the Solar system using an observing platform in low Earth orbit. A major aim of the SXO project was to investigate the production of thin

  11. Active optics: off axis aspherics generation for high contrast imaging

    Science.gov (United States)

    Hugot, E.; Laslandes, M.; Ferrari, M.; Vives, S.; Moindrot, S.; El Hadi, K.; Dohlen, K.

    2017-11-01

    Active Optics methods, based on elasticity theory, allow the aspherisation of optical surfaces by stress polishing but also active aspherisation in situ. Researches in this field will impact the final performance and the final cost of any telescope or instrument. The stress polishing method is well suited for the superpolishing of aspheric components for astronomy. Its principle relies on spherical polishing with a full-sized tool of a warped substrate, which becomes aspherical once unwarped. The main advantage of this technique is the very high optical quality obtained either on form or on high spatial frequency errors. Furthermore, the roughness can be decreased down to a few angstroms, thanks the classical polishing with a large pitch tool, providing a substantial gain on the final scientific performance, for instance on the contrast on coronagraphic images, but also on the polishing time and cost. Stress polishing is based on elasticity theory, and requires an optimised deformation system able to provide the right aspherical form on the optical surface during polishing. The optical quality of the deformation is validated using extensive Finite Element Analysis, allowing an estimation of residuals and an optimisation of the warping harness. We describe here the work realised on stress polishing of toric mirrors for VLT-SPHERE and then our actual work on off axis aspherics (OAA) for the ASPIICS-Proba3 mission for solar coronagraphy. The ASPIICS optical design made by Vives et al is a three mirrors anastigmat including a concave off axis hyperboloid and a convex off axis parabola (OAP). We are developing a prototype in order to demonstrate the feasibility of this type of surface, using a multi-mode warping harness (Lemaitre et al). Furthermore, we present our work on variable OAP, meaning the possibility to adjust the shape of a simple OAP in situ with a minimal number of actuators, typically one actuator per optical mode (Focus, Coma and Astigmatism

  12. Radiative recombination of highly charged ions: Enhanced rates at low energies

    International Nuclear Information System (INIS)

    Frank, A.; Mueller, A.; Haselbauer, J.; Schennach, S.; Spies, W.; Uwira, O.; Wagner, M.

    1992-01-01

    In a single-pass merged-beams experiment employing a dense cold electron target recombination of highly charged ions is studied. Unexpected high recombination rates are observed at low energies E cm in the electron-ion center-of-mass frame. In particular, theoretical estimates for radiative recombination are dramatically exceeded by the experimental recombination rates at E cm =0 eV for U 28+ and for Au 25+ ions. Considerable rate enhancement is also observed for Ar 15+ . This points to a general phenomenon which has to be interpreted as a consequence of high electron densities, low electron beam temperatures, high ion charge states and presence of strong magnetic fields. (orig.)

  13. The electrical charging of inactive aerosols in high ionised atmosphere, the electrical charging of artificial beta radioactive aerosols; Le processus de charge electrique: des aerosols non radioactifs en milieu fortement ionise, des aerosols radioactifs artificiels emetteurs beta

    Energy Technology Data Exchange (ETDEWEB)

    Gensdarmes, F

    2000-07-01

    The electrical properties of aerosols greatly influence their transport and deposition in a containment. In a bipolar ionic atmosphere, a neutral electric charge on aerosols is commonly assumed. However, many studies report a different charge distribution in some situations, like highly ionised atmosphere or in the case of radioactive aerosols. Such situations could arise from a hypothetical accident in a nuclear power plant. Within the framework of safety studies which are carried out at IPSN, our aims were the study of electrical properties of aerosols in highly ionised atmosphere, and the study of artificial radioactive aerosols, in order to suggest experimental validation of available theories. For this purpose, we designed an experimental device that allows us to measure non-radioactive aerosol charge distribution under high gamma irradiation, up to 10{sup 4} Gy/h. With our experimental device we also studied the properties of small ions in the medium. Our results show a variation of the charge distribution in highly ionised atmosphere. The charge increases with the dose of gamma ray. We have related this variation with the one of the small ions in the gases, according to theoretical prediction. However, the model overestimates slightly our experimental results. In the case of the radioactive aerosols, we have designed an original experimental device, which allows us to study the charge distribution of a {sup 137}Cs aerosol. Our results show that the electric charging of such aerosols is strongly dependent on evolution parameters in a containment. So, our results underline a great enhancement of self-charging of particles which are sampled in a confined medium. Our results are qualitatively in agreement with the theoretical model; nevertheless the latter underestimates appreciably the self-charging, owing to the fact that wall effects are not taken into account. (author)

  14. 2KJ/S 1KV, 25HZ PRR capacitor charging power supply with twin phase shifted primary windings to achieve high charge transfer rate and stability

    International Nuclear Information System (INIS)

    Kelkar, Y.; Singh, Y.P.; Thakurta, A.C.

    2013-01-01

    The capacitor charging power supply (CCPS) was developed to charge bank of 150uF energy storage capacitor (15uf , 10 nos in parallel) upto 1kV in 35 ms exhibiting a peak charging power of 2 kJ/s at a repetition rate of 25 pps. A CCPS observes a large change in load variations at the output. Initially the capacitor will act as a short circuit so the topology must be such that it should withstand short circuit condition repetitively. The High Voltage capacitor charging power supply consist of two identical full bridge resonant converters feeding to two primary windings of a transformer with rectified secondary connected to capacitor load. Topology selection is based on the fact that the series resonant converter with switching frequency f s , below 50% of the resonant frequency f r (f s ≤ 0.5 f r ) act as a current source. (author)

  15. Synthetic high-charge organomica: effect of the layer charge and alkyl chain length on the structure of the adsorbed surfactants.

    Science.gov (United States)

    Pazos, M Carolina; Castro, Miguel A; Orta, M Mar; Pavón, Esperanza; Valencia Rios, Jesús S; Alba, María D

    2012-05-15

    A family of organomicas was synthesized using synthetic swelling micas with high layer charge (Na(n)Si(8-n)Al(n)Mg(6)F(4)O(20)·XH(2)O, where n = 2, 3, and 4) exchanged with dodecylammonium and octadecylammonium cations. The molecular arrangement of the surfactant was elucidated on the basis on XRD patterns and DTA. The ordering conformation of the surfactant molecules into the interlayer space of micas was investigated by (13)C, (27)Al, and (29)Si MAS NMR. The arrangement of alkylammonium ions in these high-charge synthetic micas depends on the combined effects of the layer charge of the mica and the chain length of the cation. In the organomicas with dodecylammonium, a transition from a parallel layer to a bilayer-paraffin arrangement is observed when the layer charge of the mica increases. However, when octadecylammonium is the interlayer cation, the molecular arrangement of the surfactant was found to follow the bilayer-paraffin model for all values of layer charge. The amount of ordered conformation all-trans is directly proportional of layer charge.

  16. ASIC-enabled High Resolution Optical Time Domain Reflectometer

    Science.gov (United States)

    Skendzic, Sandra

    Fiber optics has become the preferred technology in communication systems because of what it has to offer: high data transmission rates, immunity to electromagnetic interference, and lightweight, flexible cables. An optical time domain reflectometer (OTDR) provides a convenient method of locating and diagnosing faults (e.g. break in a fiber) along a fiber that can obstruct crucial optical pathways. Both the ability to resolve the precise location of the fault and distinguish between two discrete, closely spaced faults are figures of merit. This thesis presents an implementation of a high resolution OTDR through the use of a compact and programmable ASIC (application specific integrated circuit). The integration of many essential OTDR functions on a single chip is advantageous over existing commercial instruments because it enables small, lightweight packaging, and offers low power and cost efficiency. Furthermore, its compactness presents the option of placing multiple ASICs in parallel, which can conceivably ease the characterization of densely populated fiber optic networks. The OTDR ASIC consists of a tunable clock, pattern generator, precise timer, electrical receiver, and signal sampling circuit. During OTDR operation, the chip generates narrow electrical pulse, which can then be converted to optical format when coupled with an external laser diode driver. The ASIC also works with an external photodetector to measure the timing and amplitude of optical reflections in a fiber. It has a 1 cm sampling resolution, which allows for a 2 cm spatial resolution. While this OTDR ASIC has been previously demonstrated for multimode fiber fault diagnostics, this thesis focuses on extending its functionality to single mode fiber. To validate this novel approach to OTDR, this thesis is divided into five chapters: (1) introduction, (2) implementation, (3), performance of ASIC-based OTDR, (4) exploration in optical pre-amplification with a semiconductor optical amplifier, and

  17. A high precision recipe for correcting images distorted by a tapered fiber optic

    International Nuclear Information System (INIS)

    Islam, M Sirajul; Kitchen, M J; Lewis, R A; Uesugi, K

    2010-01-01

    Images captured with a tapered fiber optic camera show significant spatial distortion mainly because the spatial orientation of the fiber bundles is not identical at each end of the taper. We present three different techniques for the automatic distortion correction of images acquired with a charge-coupled device (CCD) camera bonded to a tapered optical fiber. In this paper we report - (i) comparison of various methods for distortion correction (ii) extensive quantitative analysis of the techniques and (iii) experiments carried out using a high resolution fiber optic camera. A pinhole array was used to find control points in the distorted image space. These control points were then associated with their known true coordinates. To apply geometric correction, three different approaches were investigated - global polynomial fitting, local polynomial fitting and triangulated interpolation. Sub-pixel accuracy was achieved in all approaches, but the experimental results reveal that the triangulated interpolation gave the most satisfactory result for the distortion correction. The effect of proper alignment of the mask with the fiber optic taper (FOT) camera was also investigated. It was found that the overall dewarping error is minimal when the mask is almost parallel to the CCD.

  18. High speed all optical logic gates based on quantum dot semiconductor optical amplifiers.

    Science.gov (United States)

    Ma, Shaozhen; Chen, Zhe; Sun, Hongzhi; Dutta, Niloy K

    2010-03-29

    A scheme to realize all-optical Boolean logic functions AND, XOR and NOT using semiconductor optical amplifiers with quantum-dot active layers is studied. nonlinear dynamics including carrier heating and spectral hole-burning are taken into account together with the rate equations scheme. Results show with QD excited state and wetting layer serving as dual-reservoir of carriers, as well as the ultra fast carrier relaxation of the QD device, this scheme is suitable for high speed Boolean logic operations. Logic operation can be carried out up to speed of 250 Gb/s.

  19. Soliton-based ultra-high speed optical communications

    Indian Academy of Sciences (India)

    All these facts are the outcome of research on optical solitons in fibers in spite of the fact that the commonly used RZ format is not always called a soliton format. The overview presented here attempts to incorporate the role of soliton-based communications research in present day ultra-high speed communications.

  20. High speed electro optic polymer micro-ringresonator

    NARCIS (Netherlands)

    Leinse, Arne; Diemeer, Mart; Driessen, A.

    2004-01-01

    An electro-optic polymer micro-ring resonator for high speed modulation was designed, realized and characterized. The design of layer-stack and electrodes was done such that modulation frequencies up till 1 GHz should be possible. The device consists of a ridge waveguide, defined in a negative

  1. Optical Illusions: A Presentation for High School Mathematics Students.

    Science.gov (United States)

    Brandes, Louis Grant

    1983-01-01

    Optical illusions are assumed to be of interest to high school mathematics students. The article indicates how a topic can be both educational and entertaining. Readers are invited to try to construct some illusions on their own, and to see if they can classify them. (MP)

  2. Development of Smart Optical Gels with Highly Magnetically Responsive Bicelles.

    Science.gov (United States)

    Isabettini, Stéphane; Stucki, Sandro; Massabni, Sarah; Baumgartner, Mirjam E; Reckey, Pernille Q; Kohlbrecher, Joachim; Ishikawa, Takashi; Windhab, Erich J; Fischer, Peter; Kuster, Simon

    2018-03-14

    Hydrogels delivering on-demand tailorable optical properties are formidable smart materials with promising perspectives in numerous fields, including the development of modern sensors and switches, the essential quality criterion being a defined and readily measured response to environmental changes. Lanthanide ion (Ln 3+ )-chelating bicelles are interesting building blocks for such materials because of their magnetic responsive nature. Imbedding these phospholipid-based nanodiscs in a magnetically aligned state in gelatin permits an orientation-dependent retardation of polarized light. The resulting tailorable anisotropy gives the gel a well-defined optical signature observed as a birefringence signal. These phenomena were only reported for a single bicelle-gelatin pair and required high magnetic field strengths of 8 T. Herein, we demonstrate the versatility and enhance the viability of this technology with a new generation of aminocholesterol (Chol-NH 2 )-doped bicelles imbedded in two different types of gelatin. The highly magnetically responsive nature of the bicelles allowed to gel the anisotropy at commercially viable magnetic field strengths between 1 and 3 T. Thermoreversible gels with a unique optical signature were generated by exposing the system to various temperature conditions and external magnetic field strengths. The resulting optical properties were a signature of the gel's environmental history, effectively acting as a sensor. Solutions containing the bicelles simultaneously aligning parallel and perpendicular to the magnetic field directions were obtained by mixing samples chelating Tm 3+ and Dy 3+ . These systems were successfully gelled, providing a material with two distinct temperature-dependent optical characteristics. The high degree of tunability in the magnetic response of the bicelles enables encryption of the gel's optical properties. The proposed gels are viable candidates for temperature tracking of sensitive goods and provide

  3. High-k shallow traps observed by charge pumping with varying discharging times

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Szu-Han; Chen, Ching-En; Tseng, Tseung-Yuen [Department of Electronics Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Tainan, Taiwan (China); Lu, Ying-Hsin; Lo, Wen-Hung; Tsai, Jyun-Yu; Liu, Kuan-Ju [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Wang, Bin-Wei; Cao, Xi-Xin [Department of Embedded System Engineering, Peking University, Beijing, P.R.China (China); Chen, Hua-Mao [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Cheng, Osbert; Huang, Cheng-Tung; Chen, Tsai-Fu [Device Department, United Microelectronics Corporation, Tainan Science Park, Taiwan (China)

    2013-11-07

    In this paper, we investigate the influence of falling time and base level time on high-k bulk shallow traps measured by charge pumping technique in n-channel metal-oxide-semiconductor field-effect transistors with HfO{sub 2}/metal gate stacks. N{sub T}-V{sub high} {sub level} characteristic curves with different duty ratios indicate that the electron detrapping time dominates the value of N{sub T} for extra contribution of I{sub cp} traps. N{sub T} is the number of traps, and I{sub cp} is charge pumping current. By fitting discharge formula at different temperatures, the results show that extra contribution of I{sub cp} traps at high voltage are in fact high-k bulk shallow traps. This is also verified through a comparison of different interlayer thicknesses and different Ti{sub x}N{sub 1−x} metal gate concentrations. Next, N{sub T}-V{sub high} {sub level} characteristic curves with different falling times (t{sub falling} {sub time}) and base level times (t{sub base} {sub level}) show that extra contribution of I{sub cp} traps decrease with an increase in t{sub falling} {sub time}. By fitting discharge formula for different t{sub falling} {sub time}, the results show that electrons trapped in high-k bulk shallow traps first discharge to the channel and then to source and drain during t{sub falling} {sub time}. This current cannot be measured by the charge pumping technique. Subsequent measurements of N{sub T} by charge pumping technique at t{sub base} {sub level} reveal a remainder of electrons trapped in high-k bulk shallow traps.

  4. Optically Addressed Nanostructures for High Density Data Storage

    Science.gov (United States)

    2005-10-14

    beam to sub-wavelength resolutions. X. Refereed Journal Publications I. M. D. Stenner , D. J. Gauthier, and M. A. Neifeld, "The speed of information in a...profiles for high-density optical data storage," Optics Communications, Vol.253, pp.56-69, 2005. 5. M. D. Stenner , D. J. Gauthier, and M. A. Neifeld, "Fast...causal information transmission in a medium with a slow group velocity," Physical Review Letters, Vol.94, February 2005. 6. M. D. Stenner , M. A

  5. Development of high-index optical coating for security holograms

    Science.gov (United States)

    Ahmed, Nadir A. G.

    2000-10-01

    Over the past few years security holograms have grown into a complex business to prevent counterfeiting of security cards, banknotes and the like. Rapid advances in holographic technology have led to a growing requirement for optical materials and coating methods to produce such holograms at reasonable costs. These materials have specific refractive indices and are used to fabricate semi- transparent holograms. The present paper describes a coating process to deposit optical coating on flexible films inside a vacuum web metallizer for the production of high quality semi-transparent holograms.

  6. Development of fluorides for high power laser optics

    International Nuclear Information System (INIS)

    Ready, J.F.; Vora, H.

    1980-07-01

    The laser-assisted thermonuclear fusion program has significant needs for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride (LiF) possesses a combination of optical properties which are of potential use. Single-crystalline LiF is limited by low mechanical strength. In this program, we investigated the technique of press-forging to increase the mechanical strength. LiF single crystals were press-forged over the temperature range 300 to 600 0 C to produce fine-grained polycrystalline material

  7. Charge exchange (p,n) reactions to the isobaric analog states of high Z nuclei: 73< or =Z< or =92

    International Nuclear Information System (INIS)

    Hansen, L.F.; Grimes, S.M.; Poppe, C.H.; Wong, C.

    1983-01-01

    Differential cross sections have been measured for the (p,n) reaction to the isobaric analog states of 181 Ta, 197 Au, 209 Bi, 232 Th, and 238 U at an incident energy of 27 MeV. Because of the importance of collective effects in this mass region, coupled-channel calculations have been carried out in the analysis of the data. Optical potentials obtained from the Lane model for the charge exchange reaction have been used in the simultaneous analysis of coupled proton and neutron channels. The sensitivity of the calculations to the different couplings between the levels and to the magnitude of the isovector potentials, V 1 and W 1 , is discussed. The good agreement obtained between the measured and calculated (p,n) angular distributions to the analog state confirms the validity of the Lane formalism for high-Z nuclei (Z> or =50). Elastic neutron differential cross sections inferred from the coupled-channel analysis are compared with measurements available in the literature in the energy range 7--8 MeV. The results of these calculations agree with the measured values as well as the results of calculations made using global neutron optical potential parameters optimized to fit neutron data

  8. Properties of Laser-Produced Highly Charged Heavy Ions for Direct Injection Scheme

    CERN Document Server

    Sakakibara, Kazuhiko; Hayashizaki, Noriyosu; Ito, Taku; Kashiwagi, Hirotsugu; Okamura, Masahiro

    2005-01-01

    To accelerate highly charged intense ion beam, we have developed the Direct Plasma Injection Scheme (DPIS) with laser ion source. In this scheme an ion beam from a laser ion source is injected directly to a RFQ linac without a low energy beam transport (LEBT) and the beam loss in the LEBT can be avoided. We achieved high current acceleration of carbon ions (60mA) by DPIS with the high current optimized RFQ. As the next setp we will use heavier elements like Ag, Pb, Al and Cu as target in LIS (using CO2, Nd-YAG or other laser) for DPIS and will examine properties of laser-produced plasma (the relationship of between charge state and laser power density, the current dependence of the distance from the target, etc).

  9. Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

    Science.gov (United States)

    Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

    2018-02-01

    We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

  10. Study on high gain broadband optical parametric chirped pulse amplification

    International Nuclear Information System (INIS)

    Zhang, S.K.; Fujita, M.; Yamanaka, C.; Yoshida, H.; Kodama, R.; Fujita, H.; Nakatsuka, M.; Izawa, Y.

    2000-01-01

    Optical parametric chirped pulse amplification has apparent advantages over the current schemes for high energy ultrashort pulse amplification. High gain in a single pass amplification, small B-integral, low heat deposition, high contrast ratio and, especially the extremely broad gain bandwidth with large-size crystals available bring people new hope for over multi-PW level at which the existing Nd:glass systems suffered difficulties. In this paper we present simulation and experimental studies for a high gain optical parametric chirped pulse amplification system which may be used as a preamplifier to replace the current complicated regenerative system or multi-pass Ti:sapphire amplifiers. Investigations on the amplification bandwidth and gain with BBO are performed. Analysis and discussions are also given. (author)

  11. Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

    2016-11-01

    Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

  12. High-Density Near-Field Optical Disc Recording

    Science.gov (United States)

    Shinoda, Masataka; Saito, Kimihiro; Ishimoto, Tsutomu; Kondo, Takao; Nakaoki, Ariyoshi; Ide, Naoki; Furuki, Motohiro; Takeda, Minoru; Akiyama, Yuji; Shimouma, Takashi; Yamamoto, Masanobu

    2005-05-01

    We developed a high-density near-field optical recording disc system using a solid immersion lens. The near-field optical pick-up consists of a solid immersion lens with a numerical aperture of 1.84. The laser wavelength for recording is 405 nm. In order to realize the near-field optical recording disc, we used a phase-change recording media and a molded polycarbonate substrate. A clear eye pattern of 112 GB capacity with 160 nm track pitch and 50 nm bit length was observed. The equivalent areal density is 80.6 Gbit/in2. The bottom bit error rate of 3 tracks-write was 4.5× 10-5. The readout power margin and the recording power margin were ± 30.4% and ± 11.2%, respectively.

  13. High numerical aperture imaging by using multimode fibers with micro-fabricated optics

    KAUST Repository

    Bianchi, Silvio; Rajamanickam, V.; Ferrara, Lorenzo; Di Fabrizio, Enzo M.; Di Leonardo, Roberto; Liberale, Carlo

    2014-01-01

    Controlling light propagation into multimode optical fibers through spatial light modulators provides highly miniaturized endoscopes and optical micromanipulation probes. We increase the numerical aperture up to nearly 1 by micro-optics fabricated on the fiber-end.

  14. Optical control system for high-voltage terminals

    International Nuclear Information System (INIS)

    Bicek, J.J.

    1978-01-01

    An optical control system for the control of devices in the terminal of an electrostatic accelerator includes a laser that is modulated by a series of preselected codes produced by an encoder. A photodiode receiver is placed in the laser beam at the high-voltage terminal of an electrostatic accelerator. A decoder connected to the photodiode decodes the signals to provide control impulses for a plurality of devices at the high voltage of the terminal

  15. All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

    2016-01-01

    We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

  16. Self-Assembling of Tetradecylammonium Chain on Swelling High Charge Micas (Na-Mica-3 and Na-Mica-2): Effect of Alkylammonium Concentration and Mica Layer Charge.

    Science.gov (United States)

    Pazos, M Carolina; Cota, Agustín; Osuna, Francisco J; Pavón, Esperanza; Alba, María D

    2015-04-21

    A family of tetradecylammonium micas is synthesized using synthetic swelling micas with high layer charge (Na(n)Si(8-n)Al(n)Mg6F4O20·XH2O, where n = 2 and 3) exchanged with tetradecylammonium cations. The molecular arrangement of the surfactant is elucidated on the basis of XRD patterns and DTA. The ordering conformation of the surfactant molecules into the interlayer space of micas is investigated by IR/FT, (13)C, (27)Al, and (29)Si MAS NMR. The structural arrangement of the tetradecylammonium cation in the interlayer space of high-charge micas is more sensitive to the effect of the mica layer charge at high concentration. The surfactant arrangement is found to follow the bilayer-paraffin model for all values of layer charge and surfactant concentration. However, at initial concentration below the mica CEC, a lateral monolayer is also observed. The amount of ordered conformation all-trans is directly proportional to the layer charge and surfactant concentration.

  17. Novel Highly Sensitive Protein Sensors Based on Tapered Optical Fibres Modified with Au-Based Nanocoatings

    Directory of Open Access Journals (Sweden)

    Aitor Urrutia

    2016-01-01

    Full Text Available Novel protein sensors based on tapered optical fibres modified with Au coatings deposited using two different procedures are proposed. Au-based coatings are deposited onto a nonadiabatic tapered optical fibre using (i a novel facile method composed of layer-by-layer deposition consisting of polycation (poly(allylamine hydrochloride, PAH and negatively charged SiO2 nanoparticles (NPs followed by the deposition of the charged Au NPs and (ii the sputtering technique. The Au NPs and Au thin film surfaces are then modified with biotin in order to bind streptavidin (SV molecules and detect them. The sensing principle is based on the sensitivity of the transmission spectrum of the device to changes in the refractive index of the coatings induced by the SV binding to the biotin. Both sensors showed high sensitivity to SV, with the lowest measured concentration levels below 2.5 nM. The calculated binding constant for the biotin-SV pair was 2.2×10-11 M−1 when a tapered fibre modified with the LbL method was used, with a limit of detection (LoD of 271 pM. The sensor formed using sputtering had a binding constant of 1.01×10-10 M−1 with a LoD of 806 pM. These new structures and their simple fabrication technique could be used to develop other biosensors.

  18. Operating modes of high-Tc composite superconductors and thermal runaway conditions under current charging

    International Nuclear Information System (INIS)

    Romanovskii, V R; Watanabe, K

    2006-01-01

    The operating thermal and electric modes of a high-T c superconducting composite in partially and fully penetrated states induced by the charging current are investigated. They were studied under conditions in which the current charging rate, the volume fraction of the superconductor in a composite or the temperature of the cooling bath were changed. The transient behaviour of the voltage-current dependence, which is characteristic during stable and unstable increases in electric field inside the composite under a continuous current charging, is discussed. Simulations were done using zero- and one-dimensional steady and unsteady thermoelectric models with a power equation describing the virgin voltage-current characteristic of a superconductor. It is found that some thermoelectric trends underlie the shape of the voltage-current characteristic of the high-T c superconducting composite. These have to be considered during experiments in which the critical or quench currents are defined. First, in the initial stage of the fully penetrated regime (in the low voltage range), the electric field distribution does not have a uniform character. These states depend on the volume fraction of the superconductor and the current charging rate: the higher these quantities, the higher the heterogeneity of the electric field. Second, during the stable over-critical regime (in the high voltage range) occurring in complete penetration modes, the evolution of the electric field may depend on the relevant temperature increase of a composite according to the corresponding increase in its temperature-dependent heat capacity. Consequently, the shape of the voltage-current characteristic of a composite high-T c superconductor during continuous current charging, both before and after thermal runaway, has only a positive slope. Moreover, it is proved that the growth of the fully penetrated part of the voltage-current characteristic becomes less intensive when the current charging rate or the

  19. Laboratory X-ray Studies with Trapped Highly Charged Ions Using Synchrotrons and Free-electron Lasers

    Science.gov (United States)

    Crespo López-Urrutia, José R.

    2018-06-01

    Laboratory studies on highly charged ions (HCI) using electron beam ion traps (EBITs) can cover all charge states and chemical elements found in astrophysical sources. Since their introduction in 1986, a wealth of emission measurements from the optical to the x-ray range has been carried out by different groups. In most of the work, electron-impact excitation was the driving mechanism, and high resolution spectrometers were used for the diagnostic of the emitted radiation. Other recent studies included x-ray emission following charge exchange, a mechanism which is present in many astrophysical environments and can help explain some of the unknown spectral features at 3.55 keV.In the last decade, excitation and photoionization have also been investigated by exposing HCI trapped in an EBIT to intense, monochromatic radiation from free-electron lasers and synchrotron sources. Here, advanced monochromators in powerful undulator beamlines allowed us to work at photon energies from 50 eV to 15 keV while resolving the natural linewidths of x-ray transitions like the Kα complex of Fe up to the highest charge states, and to measure the oscillator strengths of, e. g., the neonlike Fe16+ spectrum. Photoionization studies have been performed for those species as well. Very recently, our novel compact EBIT with an off-axis electron gun allows for simultaneously using the photon beam downstream, enabling exact wavelength determinations referenced to HCI with accurately calculable transitions. We have performed a recalibration of the molecular and atomic oxygen soft x-ray absorption lines in the 500 eV range with an uncertainty estimate of 30 meV. This revealed a 600 meV calibration error that propagated through the literature for decades with the consequence of a 200 km/s misfit of the velocity in interstellar oxygen absorbers. Other possibilities for the compact EBIT are investigations of resonant photorecombination processes with excellent energy resolution. With the

  20. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    Directory of Open Access Journals (Sweden)

    H. W. Zhao

    2017-09-01

    Full Text Available The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24–28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of ^{40}Ar^{12+} and ^{129}Xe^{26+} have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL, China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24+18  GHz heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  1. Intense highly charged ion beam production and operation with a superconducting electron cyclotron resonance ion source

    Science.gov (United States)

    Zhao, H. W.; Sun, L. T.; Guo, J. W.; Lu, W.; Xie, D. Z.; Hitz, D.; Zhang, X. Z.; Yang, Y.

    2017-09-01

    The superconducting electron cyclotron resonance ion source with advanced design in Lanzhou (SECRAL) is a superconducting-magnet-based electron cyclotron resonance ion source (ECRIS) for the production of intense highly charged heavy ion beams. It is one of the best performing ECRISs worldwide and the first superconducting ECRIS built with an innovative magnet to generate a high strength minimum-B field for operation with heating microwaves up to 24-28 GHz. Since its commissioning in 2005, SECRAL has so far produced a good number of continuous wave intensity records of highly charged ion beams, in which recently the beam intensities of 40Ar+ and 129Xe26+ have, for the first time, exceeded 1 emA produced by an ion source. Routine operations commenced in 2007 with the Heavy Ion accelerator Research Facility in Lanzhou (HIRFL), China. Up to June 2017, SECRAL has been providing more than 28,000 hours of highly charged heavy ion beams to the accelerator demonstrating its great capability and reliability. The great achievement of SECRAL is accumulation of numerous technical advancements, such as an innovative magnetic system and an efficient double-frequency (24 +18 GHz ) heating with improved plasma stability. This article reviews the development of SECRAL and production of intense highly charged ion beams by SECRAL focusing on its unique magnet design, source commissioning, performance studies and enhancements, beam quality and long-term operation. SECRAL development and its performance studies representatively reflect the achievements and status of the present ECR ion source, as well as the ECRIS impacts on HIRFL.

  2. Van-de-Graaf accelerator operation with laser source of highly-charged heavy ions

    International Nuclear Information System (INIS)

    Barabash, L.S.; Golubev, A.A.; Koshkarev, S.G.; Krechet, K.I.; Sharkov, B.Y.; Shumshurov, A.V.

    1988-01-01

    Multicharged ions (Z = +1 divided-by +10) of practically any elements of the periodical table have been generated by the laser source based on a simple in operation and fabrication laser. One of the features of the laser source is that the energy needed for plasma heating is transported to the target from a great distance. In this case the target can be placed under high voltage or in a magnetic field. These advantages of the laser source are particularly important for its application in the Van-de-Graaf accelerator, where absence of resonance units allows to accelerate ions with any charge-to-mass ratio. The goal of this paper consists in designing a laser source of highly- charged heavy ions in the Van-de-Graaf accelerator and in measuring charge spectra of the accelerated ion beam. The peculiarities of this accelerator are taken into account in the discussion of the source scheme. Such peculiarities include potential up to 5 MV on the high-voltage conductor, where the ion source is placed, and high up to 15 atm gas environment pressure

  3. Charge injection engineering of ambipolar field-effect transistors for high-performance organic complementary circuits.

    Science.gov (United States)

    Baeg, Kang-Jun; Kim, Juhwan; Khim, Dongyoon; Caironi, Mario; Kim, Dong-Yu; You, In-Kyu; Quinn, Jordan R; Facchetti, Antonio; Noh, Yong-Young

    2011-08-01

    Ambipolar π-conjugated polymers may provide inexpensive large-area manufacturing of complementary integrated circuits (CICs) without requiring micro-patterning of the individual p- and n-channel semiconductors. However, current-generation ambipolar semiconductor-based CICs suffer from higher static power consumption, low operation frequencies, and degraded noise margins compared to complementary logics based on unipolar p- and n-channel organic field-effect transistors (OFETs). Here, we demonstrate a simple methodology to control charge injection and transport in ambipolar OFETs via engineering of the electrical contacts. Solution-processed caesium (Cs) salts, as electron-injection and hole-blocking layers at the interface between semiconductors and charge injection electrodes, significantly decrease the gold (Au) work function (∼4.1 eV) compared to that of a pristine Au electrode (∼4.7 eV). By controlling the electrode surface chemistry, excellent p-channel (hole mobility ∼0.1-0.6 cm(2)/(Vs)) and n-channel (electron mobility ∼0.1-0.3 cm(2)/(Vs)) OFET characteristics with the same semiconductor are demonstrated. Most importantly, in these OFETs the counterpart charge carrier currents are highly suppressed for depletion mode operation (I(off) 0.1-0.2 mA). Thus, high-performance, truly complementary inverters (high gain >50 and high noise margin >75% of ideal value) and ring oscillators (oscillation frequency ∼12 kHz) based on a solution-processed ambipolar polymer are demonstrated.

  4. Multifunctional hybrid diode: Study of photoresponse, high responsivity, and charge injection mechanisms

    Science.gov (United States)

    Singh, Jitendra; Singh, R. G.; Gautam, Subodh K.; Singh, Fouran

    2018-05-01

    A multifunctional hybrid heterojunction diode is developed on porous silicon and its current density-voltage characteristics reveal a good rectification ratio along with other superior parameters such as ideality factor, barrier height and series resistance. The diode also functions as an efficient photodiode to manifest high photosensitivity with high responsivity under illumination with broadband solar light, UV light, and green light. The diode is also carefully scrutinized for its sensitivity and repeatability over many cycles under UV and green light and is found to have a quick response and extremely fast recovery times. The notable responsivity is attributed to the generation of high density of excitons in the depletion region by the absorption of incident photons and their separation by an internal electric field besides an additional photocurrent due to the charging of polymer chains. The mechanisms of generation, injection and transport of charge carriers are explained by developing a schematic energy band diagram. The transport phenomenon of carriers is further investigated from room temperature down to a very low temperature of 10 K. An Arrhenius plot is made to determine the Richardson constant. Various diode parameters as mentioned above are also determined and the dominance of the transport mechanism of charge carriers in different temperature regimes such as diffusion across the junction and/or quantum tunneling through the barriers are explained. The developed multifunction heterojunction hybrid diodes have implications for highly sensitive photodiodes in the UV and visible range of electromagnetic spectrum that can be very promising for efficient optoelectronic devices.

  5. Fragile charge order in the nonsuperconducting ground state of the underdoped high-temperature superconductors.

    Science.gov (United States)

    Tan, B S; Harrison, N; Zhu, Z; Balakirev, F; Ramshaw, B J; Srivastava, A; Sabok-Sayr, S A; Sabok, S A; Dabrowski, B; Lonzarich, G G; Sebastian, Suchitra E

    2015-08-04

    The normal state in the hole underdoped copper oxide superconductors has proven to be a source of mystery for decades. The measurement of a small Fermi surface by quantum oscillations on suppression of superconductivity by high applied magnetic fields, together with complementary spectroscopic measurements in the hole underdoped copper oxide superconductors, point to a nodal electron pocket from charge order in YBa2Cu3(6+δ). Here, we report quantum oscillation measurements in the closely related stoichiometric material YBa2Cu4O8, which reveals similar Fermi surface properties to YBa2Cu3(6+δ), despite the nonobservation of charge order signatures in the same spectroscopic techniques, such as X-ray diffraction, that revealed signatures of charge order in YBa2Cu3(6+δ). Fermi surface reconstruction in YBa2Cu4O8 is suggested to occur from magnetic field enhancement of charge order that is rendered fragile in zero magnetic fields because of its potential unconventional nature and/or its occurrence as a subsidiary to more robust underlying electronic correlations.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ginzel, Rainer

    2010-06-09

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

  7. Exploring charge density analysis in crystals at high pressure: data collection, data analysis and advanced modelling.

    Science.gov (United States)

    Casati, Nicola; Genoni, Alessandro; Meyer, Benjamin; Krawczuk, Anna; Macchi, Piero

    2017-08-01

    The possibility to determine electron-density distribution in crystals has been an enormous breakthrough, stimulated by a favourable combination of equipment for X-ray and neutron diffraction at low temperature, by the development of simplified, though accurate, electron-density models refined from the experimental data and by the progress in charge density analysis often in combination with theoretical work. Many years after the first successful charge density determination and analysis, scientists face new challenges, for example: (i) determination of the finer details of the electron-density distribution in the atomic cores, (ii) simultaneous refinement of electron charge and spin density or (iii) measuring crystals under perturbation. In this context, the possibility of obtaining experimental charge density at high pressure has recently been demonstrated [Casati et al. (2016). Nat. Commun. 7, 10901]. This paper reports on the necessities and pitfalls of this new challenge, focusing on the species syn-1,6:8,13-biscarbonyl[14]annulene. The experimental requirements, the expected data quality and data corrections are discussed in detail, including warnings about possible shortcomings. At the same time, new modelling techniques are proposed, which could enable specific information to be extracted, from the limited and less accurate observations, like the degree of localization of double bonds, which is fundamental to the scientific case under examination.

  8. Optical spin-to-orbital angular momentum conversion in ultra-thin metasurfaces with arbitrary topological charges

    Energy Technology Data Exchange (ETDEWEB)

    Bouchard, Frédéric; De Leon, Israel; Schulz, Sebastian A.; Upham, Jeremy; Karimi, Ebrahim, E-mail: ekarimi@uottawa.ca [Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5 Canada (Canada); Boyd, Robert W. [Department of Physics, University of Ottawa, 25 Templeton, Ottawa, Ontario K1N 6N5 Canada (Canada); Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

    2014-09-08

    Orbital angular momentum associated with the helical phase-front of optical beams provides an unbounded “space” for both classical and quantum communications. Among the different approaches to generate and manipulate orbital angular momentum states of light, coupling between spin and orbital angular momentum allows a faster manipulation of orbital angular momentum states because it depends on manipulating the polarisation state of light, which is simpler and generally faster than manipulating conventional orbital angular momentum generators. In this work, we design and fabricate an ultra-thin spin-to-orbital angular momentum converter, based on plasmonic nano-antennas and operating in the visible wavelength range that is capable of converting spin to an arbitrary value of orbital angular momentum ℓ. The nano-antennas are arranged in an array with a well-defined geometry in the transverse plane of the beam, possessing a specific integer or half-integer topological charge q. When a circularly polarised light beam traverses this metasurface, the output beam polarisation switches handedness and the orbital angular momentum changes in value by ℓ=±2qℏ per photon. We experimentally demonstrate ℓ values ranging from ±1 to ±25 with conversion efficiencies of 8.6% ± 0.4%. Our ultra-thin devices are integratable and thus suitable for applications in quantum communications, quantum computations, and nano-scale sensing.

  9. Optical spin-to-orbital angular momentum conversion in ultra-thin metasurfaces with arbitrary topological charges

    International Nuclear Information System (INIS)

    Bouchard, Frédéric; De Leon, Israel; Schulz, Sebastian A.; Upham, Jeremy; Karimi, Ebrahim; Boyd, Robert W.

    2014-01-01

    Orbital angular momentum associated with the helical phase-front of optical beams provides an unbounded “space” for both classical and quantum communications. Among the different approaches to generate and manipulate orbital angular momentum states of light, coupling between spin and orbital angular momentum allows a faster manipulation of orbital angular momentum states because it depends on manipulating the polarisation state of light, which is simpler and generally faster than manipulating conventional orbital angular momentum generators. In this work, we design and fabricate an ultra-thin spin-to-orbital angular momentum converter, based on plasmonic nano-antennas and operating in the visible wavelength range that is capable of converting spin to an arbitrary value of orbital angular momentum ℓ. The nano-antennas are arranged in an array with a well-defined geometry in the transverse plane of the beam, possessing a specific integer or half-integer topological charge q. When a circularly polarised light beam traverses this metasurface, the output beam polarisation switches handedness and the orbital angular momentum changes in value by ℓ=±2qℏ per photon. We experimentally demonstrate ℓ values ranging from ±1 to ±25 with conversion efficiencies of 8.6% ± 0.4%. Our ultra-thin devices are integratable and thus suitable for applications in quantum communications, quantum computations, and nano-scale sensing.

  10. Compact and high-resolution optical orbital angular momentum sorter

    Directory of Open Access Journals (Sweden)

    Chenhao Wan

    2017-03-01

    Full Text Available A compact and high-resolution optical orbital angular momentum (OAM sorter is proposed and demonstrated. The sorter comprises a quadratic fan-out mapper and a dual-phase corrector positioned in the pupil plane and the Fourier plane, respectively. The optical system is greatly simplified compared to previous demonstrations of OAM sorting, and the performance in resolution and efficiency is maintained. A folded configuration is set up using a single reflective spatial light modulator (SLM to demonstrate the validity of the scheme. The two phase elements are implemented on the left and right halves of the SLM and connected by a right-angle prism. Experimental results demonstrate the high resolution of the compact OAM sorter, and the current limit in efficiency can be overcome by replacing with transmissive SLMs and removing the beam splitters. This novel scheme paves the way for the miniaturization and integration of high-resolution OAM sorters.

  11. High-throughput optical system for HDES hyperspectral imager

    Science.gov (United States)

    Václavík, Jan; Melich, Radek; Pintr, Pavel; Pleštil, Jan

    2015-01-01

    Affordable, long-wave infrared hyperspectral imaging calls for use of an uncooled FPA with high-throughput optics. This paper describes the design of the optical part of a stationary hyperspectral imager in a spectral range of 7-14 um with a field of view of 20°×10°. The imager employs a push-broom method made by a scanning mirror. High throughput and a demand for simplicity and rigidity led to a fully refractive design with highly aspheric surfaces and off-axis positioning of the detector array. The design was optimized to exploit the machinability of infrared materials by the SPDT method and a simple assemblage.

  12. Nanoscale transformation of sp2 to sp3 of graphite by slow highly charged ion irradiation

    International Nuclear Information System (INIS)

    Meguro, T.; Hida, A.; Koguchi, Y.; Miyamoto, S.; Yamamoto, Y.; Takai, H.; Maeda, K.; Aoyagi, Y.

    2003-01-01

    Nanoscale transformation of electronic states by highly charged ion (HCI) impact on graphite surfaces is described. The high potential energy of slow HCI, which induces multiple emission of electrons from the surface, provides a strong modification of the electronic states of the local area upon graphite surfaces. The HCI impact and the subsequent surface treatment either by electron injection from a scanning tunneling microscopy tip or by He-Cd laser irradiation induce a localized transition from sp 2 to sp 3 hybridization in graphite, resulting in the formation of nanoscale diamond-like structures (nanodiamond) at the impact region. From Raman spectroscopic measurements on sp 2 related peaks, it is found that the HCI irradiation creates vacancy complexes in contrast to ions having a lower charge state, which generate single vacancies. It is of interest that a single impact of HCI creates one nanodiamond structure, suggesting potential applications of HCI in nanoscale material processing

  13. Near UV-visible line emission from tungsten highly-charged ions in Large Helical Device

    International Nuclear Information System (INIS)

    Kato, D.; Sakaue, H.A.; Murakami, I.; Goto, M.; Oishi, T.; Morita, S.; Fujii, K.; Nakamura, N.; Koike, F.; Sasaki, Akira; Ding, X.-B.; Dong, C.-Z.

    2015-01-01

    Wavelengths of emission lines from tungsten highly-charged ions have been precisely measured in near UV-visible range (320 - 356 nm and 382 - 402 nm) at Large Helical Device (LHD) by tungsten pellet injection. The tungsten emission lines were assigned based on its line-integrated intensity profiles on a poloidal cross section. The ground-term magnetic-dipole (M1) lines of W 26+,27+ and an M1 line of a metastable excited state of W 28+ , whose wavelengths have been determined by measurements using electron-beam-ion-traps (EBITs), are identified in the LHD spectra. The present results partially compliment wavelength data of tungsten highly-charged ions in the near UV-visible range. (author)

  14. The Frankfurt ECRIS-RFQ facility for materials research with highly charged ions

    International Nuclear Information System (INIS)

    Stiebing, K.; Streitz, H.; Schmidt, L.; Schremmer, A.; Bethge, K.; Schmidt-Boecking, H.; Schempp, A.; Bessler, U.; Beller, P.; Madlung, J.

    1996-01-01

    The new accelerator for the production of highly charged heavy ions, presently installed at the Institut fuer Kernphysik consists of a 14 GHz ECR source in combination with an variable-energy RFQ post-accelerator. It is designed to deliver highly charged ions in the energy range between 1 keV/u (the ECRIS beam) and 100-200 keV/u with the (variable-energy radio frequency quadrupole) VE-RFQ. Investigations of transient processes with ns time constants will be possible by a single bunch system. Another attractive feature for materials research is the combination with ion beams from the 7 MV Van de Graaff. The status of the project and first results of beam measurements will be pre sented. (orig.)

  15. High-speed scattering of charged and uncharged particles in general relativity

    International Nuclear Information System (INIS)

    Westphal, K.

    1985-01-01

    After a brief consideration of the high-speed scattering of two point charges high-speed scattering is thoroughly discussed for a charged particle by a fixed mass and of two uncharged particles of comparable masses. Perturbation technique is used over Minkowski spacetime in the de Donder gauge and the field equations and the resulting equations of motion (which take the reaction of the particles' quasistatic self-field into account) are solved by iteration. The obtained energy-momentum conservation laws allow the computation of second-order corrections for the scattering angle and the cross section. The asymptotic structure of the far-field indicates synchrotron radiation (electromagnetic and gravitational, respectively) which causes an energy loss whose reaction on the motion is briefly considered in the low-velocity limit including bound motion. (For neutral particles this is a third-order effect.) (author)

  16. High-energy charged particle bursts in the near-Earth space as earthquake precursors

    Directory of Open Access Journals (Sweden)

    S. Yu. Aleksandrin

    2003-02-01

    Full Text Available The experimental data on high-energy charged particle fluxes, obtained in various near-Earth space experiments (MIR orbital station, METEOR-3, GAMMA and SAMPEX satellites were processed and analyzed with the goal to search for particle bursts. Particle bursts have been selected in every experiment considered. It was shown that the significant part of high-energy charged particle bursts correlates with seismic activity. Moreover, the particle bursts are observed several hours before strong earthquakes; L-shells of particle bursts and corresponding earthquakes are practically the same. Some features of a seismo-magnetosphere connection model, based on the interaction of electromagnetic emission of seismic origin and radiation belt particles, were considered. Key words. Ionospheric physics (energetic particles, trapped; energetic particles, precipitating; magnetosphere-ionosphere interactions

  17. On-chip high-voltage generator design design methodology for charge pumps

    CERN Document Server

    Tanzawa, Toru

    2016-01-01

    This book provides various design techniques for switched-capacitor on-chip high-voltage generators, including charge pump circuits, regulators, level shifters, references, and oscillators.  Readers will see these techniques applied to system design in order to address the challenge of how the on-chip high-voltage generator is designed for Flash memories, LCD drivers, and other semiconductor devices to optimize the entire circuit area and power efficiency with a low voltage supply, while minimizing the cost.  This new edition includes a variety of useful updates, including coverage of power efficiency and comprehensive optimization methodologies for DC-DC voltage multipliers, modeling of extremely low voltage Dickson charge pumps, and modeling and optimum design of AC-DC switched-capacitor multipliers for energy harvesting and power transfer for RFID.

  18. Charge exchange as a recombination mechanism in high-temperature plasmas

    International Nuclear Information System (INIS)

    Hulse, R.A.; Post, D.E.; Mikkelsen, D.R.

    1980-03-01

    Charge exchange with neutral hydrogen is examined as a recombination mechanism for multi-charged impurity ions present in high-temperature fusion plasmas. At sufficiently low electron densities, fluxes of atomic hydrogen produced by either the injection of neutral heating beams or the background of thermal neutrals can yield an important or even dominant recombination process for such ions. Equilibrium results are given for selected impurity elements showing the altered ionization balance and radiative cooling rate produced by the presence of various neutral populations. A notable result is that the stripping of impurities to relatively non-radiative ionization states with increasing electron temperature can be postponed or entirely prevented by the application of intense neutral beam heating power. A time dependent calculation modelling the behavior of iron in recent PLT tokamak high power neutral beam heating experiments is also presented

  19. Two and three electron Auger transitions in collisions of highly-charged ions with surfaces

    International Nuclear Information System (INIS)

    Moretto-Capelle, P.; Bordenave-Montesquieu, A.; Benoit-Cattin, P.; Andriamonje, S.; Andrae, H.J.

    1991-01-01

    The Auger electron spectra from Ar 9+ approaching at 265 eV a Si or metal surface in vacua of 10 -5 Pa or UHV are identical. Experiments on atomic physics in front of surfaces are thus possible in standard vacuum. N 7+ approaching a surface at 1000 eV penetrates with great probability into the bulk and gives rise to K 2 L 2 L double Auger lines, observed for the first time with low energy highly charged ions. (orig.)

  20. The charge deposition in the numerical simulation of high-current beam

    International Nuclear Information System (INIS)

    Wang Shijun

    1987-01-01

    A new method of charge deposition of high-current beam, conservation-map method, is given. THe advantages of Neil's and other various methods are adopted. The mistake of Neil's method and the limitation of other various methods is discarded. So the method is accurate without additional assumption. The method not only applies to the case of steady laminar flow but also applies to the case of steady non-laminar flow

  1. Charge-coupled devices for particle detection with high spatial resolution

    International Nuclear Information System (INIS)

    Farley, F.J.; Damerell, C.J.S.; Gillman, A.R.; Wickens, F.J.

    1980-10-01

    The results of a study of the possible application of a thin microelectronic device (the charge-coupled device) to high energy physics as particle detectors with good spatial resolution which can distinguish between tracks emerging from the primary vertex and those from secondary vertices due to the decay of short lived particles with higher flavours, are reported. Performance characteristics indicating the spatial resolution, particle discrimination, time resolution, readout time and lifetime of such detectors have been obtained. (U.K.)

  2. K-Vacancy Production in the Collision of Highly Charged Relativistic Ions With Heavy Atoms

    OpenAIRE

    KHABIBULLAEV, P. K.

    2014-01-01

    A general expression for the cross section of the inelastic collision of relativistic highly charged ion with heavy (relativistic) atoms is obtained using the generalized eikonal approximation. In the ultrarelativistic limit, the obtained formula coincides with a known exact one. As an application of the obtained result, probability and cross section of the K-vacany production in the U92+ - U91+ collision are calculated.

  3. Advancement of highly charged ion beam production by superconducting ECR ion source SECRAL (invited)

    International Nuclear Information System (INIS)

    Sun, L.; Lu, W.; Zhang, W. H.; Feng, Y. C.; Qian, C.; Ma, H. Y.; Zhang, X. Z.; Zhao, H. W.; Guo, J. W.; Yang, Y.; Fang, X.

    2016-01-01

    At Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), the superconducting Electron Cyclotron Resonance (ECR) ion source SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) has been put into operation for about 10 years now. It has been the main working horse to deliver intense highly charged heavy ion beams for the accelerators. Since its first plasma at 18 GHz, R&D work towards more intense highly charged ion beam production as well as the beam quality investigation has never been stopped. When SECRAL was upgraded to its typical operation frequency 24 GHz, it had already showed its promising capacity of very intense highly charged ion beam production. And it has also provided the strong experimental support for the so called scaling laws of microwave frequency effect. However, compared to the microwave power heating efficiency at 18 GHz, 24 GHz microwave heating does not show the ω 2 scale at the same power level, which indicates that microwave power coupling at gyrotron frequency needs better understanding. In this paper, after a review of the operation status of SECRAL with regard to the beam availability and stability, the recent study of the extracted ion beam transverse coupling issues will be discussed, and the test results of the both TE 01 and HE 11 modes will be presented. A general comparison of the performance working with the two injection modes will be given, and a preliminary analysis will be introduced. The latest results of the production of very intense highly charged ion beams, such as 1.42 emA Ar 12+ , 0.92 emA Xe 27+ , and so on, will be presented

  4. Space charge and wake field analysis for a high brightness electron source

    International Nuclear Information System (INIS)

    Parsa, Z.

    1991-01-01

    We present a brief overview of the formalism used, and some simulation results for transverse and longitudinal motion of a bunch of particles moving through a cavity (e.g., the Brookhaven National Laboratory high brightness photocathode gun), including effects of the accelerating field, space charge forces (e.g., arising from the interaction of the cavity surface and the self field of the bunch). 3 refs., 12 figs

  5. Extreme ultraviolet spectroscopy of highly charged argon ions at the Berlin EBIT

    International Nuclear Information System (INIS)

    Biedermann, C; Radtke, R; Fussmann, G; Allen, F I

    2007-01-01

    Extreme ultraviolet radiation from highly charged argon was investigated at the Berlin Electron Beam Ion Trap with a 2 m grazing incidence spectrometer. Lines in the wavelength range 150 to 660 A originating from C-like Ar 12+ to Li-like Ar 15+ ions have been identified and are compared with database information from solar line lists and predictions. Line ratios for the observed resonance, intercombination and forbidden lines offer important diagnostic capabilities for low density, hot plasmas

  6. High-energy charged particles in space at one astronomical unit

    International Nuclear Information System (INIS)

    Feynman, J.; Gabriel, S.B.

    1996-01-01

    Single-event effects and many other spacecraft anomalies are caused by positively charged high-energy particles impinging on the vehicle and its component parts. Here, the authors review the current knowledge of the interplanetary particle environment in the energy ranges that are most important for these effects. State-of-the-art engineering models are described briefly along with comments on the future work required in this field

  7. How nonlinear optics can merge interferometry for high resolution imaging

    Science.gov (United States)

    Ceus, D.; Reynaud, F.; Tonello, A.; Delage, L.; Grossard, L.

    2017-11-01

    High resolution stellar interferometers are very powerful efficient instruments to get a better knowledge of our Universe through the spatial coherence analysis of the light. For this purpose, the optical fields collected by each telescope Ti are mixed together. From the interferometric pattern, two expected information called the contrast Cij and the phase information φij are extracted. These information lead to the Vij, called the complex visibility, with Vij=Cijexp(jφij). For each telescope doublet TiTj, it is possible to get a complex visibility Vij. The Zernike Van Cittert theorem gives a relationship between the intensity distribution of the object observed and the complex visibility. The combination of the acquired complex visibilities and a reconstruction algorithm allows imaging reconstruction. To avoid lots of technical difficulties related to infrared optics (components transmission, thermal noises, thermal cooling…), our team proposes to explore the possibility of using nonlinear optical techniques. This is a promising alternative detection technique for detecting infrared optical signals. This way, we experimentally demonstrate that frequency conversion does not result in additional bias on the interferometric data supplied by a stellar interferometer. In this presentation, we report on wavelength conversion of the light collected by each telescope from the infrared domain to the visible. The interferometric pattern is observed in the visible domain with our, so called, upconversion interferometer. Thereby, one can benefit from mature optical components mainly used in optical telecommunications (waveguide, coupler, multiplexer…) and efficient low-noise detection schemes up to the single-photon counting level.

  8. HIGH RESOLUTION OPTICAL AND NIR SPECTRA OF HBC 722

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong-Eun; Park, Sunkyung [School of Space Research, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701 (Korea, Republic of); Green, Joel D.; Cochran, William D. [Department of Astronomy, University of Texas at Austin, TX (United States); Kang, Wonseok; Lee, Sang-Gak [National Youth Space Center, 200 Deokheungyangjjok-gil, Dongil-myeon, Goheung-gun, Jeollanam-do 548-951 (Korea, Republic of); Sung, Hyun-Il, E-mail: jeongeun.lee@khu.ac.kr, E-mail: sunkyung@khu.ac.kr, E-mail: joel@astro.as.utexas.edu, E-mail: wdc@astro.as.utexas.edu, E-mail: wskang@kywa.or.kr, E-mail: sanggak@kywa.or.kr, E-mail: hisung@kasi.re.kr [Korea Astronomy and Space Science Institute, 776 Daedeok-daero, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

    2015-07-01

    We present the results of high resolution (R ≥ 30,000) optical and near-IR spectroscopic monitoring observations of HBC 722, a recent FU Orionis object that underwent an accretion burst in 2010. We observed HBC 722 in the optical/near-IR with the Bohyunsan Optical Echelle Spectrograph, Hobby–Eberly Telescope-HRS, and Immersion Grating Infrared Spectrograph, at various points in the outburst. We found atomic lines with strongly blueshifted absorption features or P Cygni profiles, both evidence of a wind driven by the accretion. Some lines show a broad double-peaked absorption feature, evidence of disk rotation. However, the wind-driven and disk-driven spectroscopic features are anti-correlated in time; the disk features became strong as the wind features disappeared. This anti-correlation might indicate that the rebuilding of the inner disk was interrupted by the wind pressure during the first 2 years. The half-width at half-depth of the double-peaked profiles decreases with wavelength, indicative of the Keplerian rotation; the optical spectra with the disk feature are fitted by a G5 template stellar spectrum convolved with a rotation velocity of 70 km s{sup −1} while the near-IR disk features are fitted by a K5 template stellar spectrum convolved with a rotation velocity of 50 km s{sup −1}. Therefore, the optical and near-IR spectra seem to trace the disk at 39 and 76 R{sub ⊙}, respectively. We fit a power-law temperature distribution in the disk, finding an index of 0.8, comparable to optically thick accretion disk models.

  9. Improved charge-coupled device detectors for high-speed, charge exchange spectroscopy studies on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Burrell, K.H.; Gohil, P.; Groebner, R.J.; Kaplan, D.H.; Robinson, J.I.; Solomon, W.M.

    2004-01-01

    Charge exchange spectroscopy is one of the key ion diagnostics on the DIII-D tokamak. It allows determination of ion temperature, poloidal and toroidal velocity, impurity density, and radial electric field E r throughout the plasma. For the 2003 experimental campaign, we replaced the intensified photodiode array detectors on the central portion of the DIII-D charge exchange spectroscopy system with advanced charge-coupled device (CCD) detectors mounted on faster (f/4.7) Czerny-Turner spectrometers equipped with toroidal mirrors. The CCD detectors are improved versions of the ones installed on our edge system in 1999. The combination improved the photoelectron signal level by about a factor of 20 and the signal to noise by a factor of 2-8, depending on the absolute signal level. The new cameras also allow shorter minimum integration times while archiving to PC memory: 0.552 ms for the slower, lower-read noise (15 e) readout mode and 0.274 ms in the faster, higher-read noise (30 e) mode

  10. Channel mobility degradation and charge trapping in high-k/metal gate NMOSFETs

    International Nuclear Information System (INIS)

    Mathew, Shajan; Bera, L.K.; Balasubramanian, N.; Joo, M.S.; Cho, B.J.

    2004-01-01

    NMOSFETs with Metalo-Organic Chemical Vapor Deposited (MOCVD) HfAlO gate dielectric and TiN metal gate have been fabricated. Channel electron mobility was measured using the split-CV method and compared with SiO 2 devices. All high-k devices showed lower mobility compared with SiO 2 reference devices. High-k MOSFETs exhibited significant charge trapping and threshold instability. Threshold voltage recovery with time was studied on devices with oxide/nitride interfacial layer between high-k film and silicon substrate

  11. Proceedings of the workshop on opportunities for atomic physics using slow, highly-charged ions

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The study of atomic physics with highly-charged ions is an area of intense activity at the present time because of a convergence of theoretical interest and advances in experimental techniques. The purpose of the Argonne ''Workshop on Opportunities for Atomic Physics Using Slow, Highly-Charged Ions'' was to bring together atomic, nuclear, and accelerator physicists in order to identify what new facilities would be most useful for the atomic physics community. The program included discussion of existing once-through machines, advanced ion sources, recoil ion techniques, ion traps, and cooler rings. One of the topics of the Workshop was to discuss possible improvement to the ANL Tandem-Linac facility (ATLAS) to enhance the capability for slowing down ions after they are stripped to a high-charge state (the Accel/Decel technique). Another topic was the opportunity for atomic physics provided by the ECR ion source which is being built for the Uranium Upgrade of ATLAS. 18 analytics were prepared for the individual papers in this volume.

  12. Experiments with highly-charged heavy-ions performed at the storage ring ESR

    International Nuclear Information System (INIS)

    Mokler, P.H.

    1992-01-01

    The new heavy ion accelerator facility SIS/ESR was inaugurated in April 1990. During 1991 the experimental storage ring, ESR, has been commissioned. Highly-charged heavy ions from O 8+ up to Bi 82+ were successfully accumulated, cooled, and stored in the ring. Now all highly-charged, heavy ions can be provided for experiments at comfortable storage times and at energies roughly between 100 and 500 MeV/u. A report on the achievements and on the first experimental results will be given. For the experiments, special emphasis is put on capture processes in the electron cooler, i.e. on radiative and dielectronic recombination processes as well as on capture events of bound target electrons from a gas jet. In this case, the capture leads either directly (REC) or by cascading to X-ray emission, which is also exploited for a precision spectroscopy of the structure of the heaviest ions. Another exciting topic is the radioactive decay of highly charged ions: For instance the β-decay into bound atomic states, which is not possible for neutral atoms, was studied for stored naked Dy ions. (orig.)

  13. Proceedings of the workshop on opportunities for atomic physics using slow, highly-charged ions

    International Nuclear Information System (INIS)

    1987-01-01

    The study of atomic physics with highly-charged ions is an area of intense activity at the present time because of a convergence of theoretical interest and advances in experimental techniques. The purpose of the Argonne ''Workshop on Opportunities for Atomic Physics Using Slow, Highly-Charged Ions'' was to bring together atomic, nuclear, and accelerator physicists in order to identify what new facilities would be most useful for the atomic physics community. The program included discussion of existing once-through machines, advanced ion sources, recoil ion techniques, ion traps, and cooler rings. One of the topics of the Workshop was to discuss possible improvement to the ANL Tandem-Linac facility (ATLAS) to enhance the capability for slowing down ions after they are stripped to a high-charge state (the Accel/Decel technique). Another topic was the opportunity for atomic physics provided by the ECR ion source which is being built for the Uranium Upgrade of ATLAS. 18 analytics were prepared for the individual papers in this volume

  14. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Single ion induced surface nanostructures: a comparison between slow highly charged and swift heavy ions.

    Science.gov (United States)

    Aumayr, Friedrich; Facsko, Stefan; El-Said, Ayman S; Trautmann, Christina; Schleberger, Marika

    2011-10-05

    This topical review focuses on recent advances in the understanding of the formation of surface nanostructures, an intriguing phenomenon in ion-surface interaction due to the impact of individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by the formation of a surface nanostructure. More recently, a similar nanometric surface effect has been revealed for the impact of individual, very slow but highly charged ions. While swift ions transfer their large kinetic energy to the target via ionization and electronic excitation processes (electronic stopping), slow highly charged ions produce surface structures due to potential energy deposited at the top surface layers. Despite the differences in primary excitation, the similarity between the nanostructures is striking and strongly points to a common mechanism related to the energy transfer from the electronic to the lattice system of the target. A comparison of surface structures induced by swift heavy ions and slow highly charged ions provides a valuable insight to better understand the formation mechanisms. © 2011 IOP Publishing Ltd

  16. Atomic physics and synchrotron radiation: The production and accumulation of highly charged ions

    International Nuclear Information System (INIS)

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

    1986-01-01

    Synchrotron radiation can be used to produce highly-charged ions, and to study photoexcitation and photoionization for ions of virtually any element in the periodic table. To date, with few exceptions, atomic physics studies have been limited to rare gases and a few metal vapors, and to photoexcitation energies in the VUV region of the electromagnetic spectrum. These limitations can now be overcome using photons produced by high-brightness synchrotron storage rings, such as the x-ray ring at the National Synchrotron Light Source (NSLS) at Brookhaven. Furthermore, calculations indicate that irradiation of an ion trap with an intense energetic photon beam will result in a viable source of highly-charged ions that can be given the name PHOBIS: the PHOton Beam Ion Source. Promising results, which encourage the wider systematic use of synchrotron radiation in atomic physics research, have been obtained in recent experiments on VUV photoemission and the production and storage of multiply-charged ions. 26 refs., 4 figs., 1 tab

  17. Optical performance monitoring in high-speed optical fiber communication systems

    Science.gov (United States)

    Yu, Changyuan; Yang, Jing; Hu, Junhao; Zhang, Banghong

    2011-11-01

    Optical performance monitoring (OPM) becomes an attractive topic as the rapid growth of data rate in optical communication networks. It provides improved operation of the high capacity optical transmission systems. Among the various impairments, chromatic dispersion (CD) is one of major factors limiting the transmission distance in high-speed communication systems. Polarization-mode dispersion (PMD) also becomes a degrading effect in the system with data rate larger than 40 Gbit/s. In this paper, we summarize several CD and PMD monitoring methods based on RF spectrum analysis and delay-tap sampling. By using a narrow band fiber Bragg grating (FBG) notch filter, centered at 10 GHz away from the optical carrier, 10-GHz RF power can be used as a CD-insensitive PMD monitoring signal. By taking the 10-GHz RF power ratio of non-filtered and filtered signal, PMD-insensitive CD monitoring can be achieved. If the FBG notch filter is placed at optical carrier, the RF clock power ratio between non-filtered and filtered signal is also a PMDinsensitive CD monitoring parameter, which has larger RF power dynamic range and better measurement resolution. Both simulation and experiment results show that the proposed methods are efficient on measuring CD and PMD values in 57-Gbit/s D8PSK systems. Delay-tap sampling is another efficient method of measuring residual CD. Amplitude ratio of asynchronous delay-tap sampling plot decreases with CD monotonously, and the amplitude ratio can be obtained by using low bandwidth balanced receiver. The simulated results show that our method is efficient on residual CD measurement in 50-Gbit/s 50% RZ DQPSK systems with a 12-GHz balanced receiver. Since no modification on the transmitter or receiver is required, the proposed scheme is simple and cost effective.

  18. Adaptive optics with pupil tracking for high resolution retinal imaging.

    Science.gov (United States)

    Sahin, Betul; Lamory, Barbara; Levecq, Xavier; Harms, Fabrice; Dainty, Chris

    2012-02-01

    Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics.

  19. High charge state metal ion production in vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1994-01-01

    The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

  20. Field test investigation of high sensitivity fiber optic seismic geophone

    Science.gov (United States)

    Wang, Meng; Min, Li; Zhang, Xiaolei; Zhang, Faxiang; Sun, Zhihui; Li, Shujuan; Wang, Chang; Zhao, Zhong; Hao, Guanghu

    2017-10-01

    Seismic reflection, whose measured signal is the artificial seismic waves ,is the most effective method and widely used in the geophysical prospecting. And this method can be used for exploration of oil, gas and coal. When a seismic wave travelling through the Earth encounters an interface between two materials with different acoustic impedances, some of the wave energy will reflect off the interface and some will refract through the interface. At its most basic, the seismic reflection technique consists of generating seismic waves and measuring the time taken for the waves to travel from the source, reflect off an interface and be detected by an array of geophones at the surface. Compared to traditional geophones such as electric, magnetic, mechanical and gas geophone, optical fiber geophones have many advantages. Optical fiber geophones can achieve sensing and signal transmission simultaneously. With the development of fiber grating sensor technology, fiber bragg grating (FBG) is being applied in seismic exploration and draws more and more attention to its advantage of anti-electromagnetic interference, high sensitivity and insensitivity to meteorological conditions. In this paper, we designed a high sensitivity geophone and tested its sensitivity, based on the theory of FBG sensing. The frequency response range is from 10 Hz to 100 Hz and the acceleration of the fiber optic seismic geophone is over 1000pm/g. sixteen-element fiber optic seismic geophone array system is presented and the field test is performed in Shengli oilfield of China. The field test shows that: (1) the fiber optic seismic geophone has a higher sensitivity than the traditional geophone between 1-100 Hz;(2) The low frequency reflection wave continuity of fiber Bragg grating geophone is better.