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Sample records for beam induced luminescence

  1. Ion beam induced luminescence analysis of painting pigments

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, A. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy); E-mail: quaranta@ing.unitn.it; Salomon, J. [Centre de Recherche et de Restauration des Musees de France, CNRS UMR 171, rue des Pyramides, 75041 Paris Cedex 01 (France); Dran, J.C. [Centre de Recherche et de Restauration des Musees de France, CNRS UMR 171, rue des Pyramides, 75041 Paris Cedex 01 (France); Tonezzer, M. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy); Della Mea, G. [Universita di Trento, Dipartimento di Ingegneria dei Materiali e, delle Tecnologie Inustriali (DIMTI), via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via Universita 2, I-35020, Legnaro, Padova (Italy)

    2007-01-15

    Ion beam induced luminescence (IBIL) has been exploited for the first time in the analysis of inorganic painting pigments. The elemental constituents of the different compounds have been determined by particle induced X-ray emission (PIXE). The acquisition time of each spectrum ranges from 100 ms to a few seconds, depending on the luminescence intensity. The luminescence features are fingerprints of the different compounds, thus identifying the provenience of pigments of the same nominal composition. Organic varnish layers do not affect the IBIL features, allowing the identification of pigments, like lapis-lazuli, whose identification with PIXE is hindered by the varnish. IBIL proved to be a technique complementary to PIXE in the archeometry and cultural heritage analysis fields.

  2. Ion beam induced luminescence of materials

    CERN Document Server

    Brooks, R

    2001-01-01

    luminescence dead zone at the domain walls. Neodymium-yttrium-aluminium garnet (Nd:YAG) was examined and the spectra measured as a function of temperature to show the evolution of intensity of the narrow line emission from the Nd rare earth. Shifts and changes in the intrinsic UV band in the YAG material were also apparent. Thin films of alumina grown on silica on a silicon substrate, along with some that contained copper nanoclusters were also examined. TRIM software was used to model the rate of excitation within the different layers of the material for the various implant energies and to identify the source of the luminescence profile observed in each case. Evidence of thin film interference fringes was apparent in the spectra by fringe patterns modulated onto the luminescence signal as a function of wavelength and film thickness. Analysis of an alkali feldspar material using IBL, and combined with work done using RL and CL experiments, showed a shift towards lower wavelengths of the main red/IR band with ...

  3. Ion beam induced luminescence characterisation of CVD diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Gonon, P.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

  4. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.B., E-mail: ahmad.rabilal@gmail.com [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); McNeill, F.E., E-mail: fmcneill@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Byun, S.H., E-mail: soohyun@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Prestwich, W.V., E-mail: prestwic@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Seymour, C., E-mail: seymouc@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Mothersill, C.E., E-mail: mothers@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada)

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced 'bystander effects' studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 Multiplication-Sign 10{sup 13} H{sup +}/cm{sup 2} s. The average saturation value for the photon output was found to be 40 Multiplication-Sign 10{sup 6} cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 Multiplication-Sign 10{sup 3}, 10 Multiplication-Sign 10{sup 6}, and 35 Multiplication-Sign 10{sup 6} cps for wavelengths of 280 {+-} 5 nm, 320 {+-} 5 nm and 340 {+-} 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a 'damage cross section' of the order of 10{sup -14} cm{sup 2}. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  5. Ion beam induced luminescence from diamond using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Bettiol, A.A.; Jamieson, D. N.; Prawer, S.; Allen, M.G. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1993-12-31

    Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

  6. Ion beam induced luminescence of germano-silicate optical fiber preform

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Youngwoong; Han, Wontaek [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Markovic, Nikola; Jaksic, Milko [Ruder Boskovic Institute, Zagred (Croatia)

    2014-05-15

    When an optical fiber is exposed to radiation, the attenuation (RIA, Radiation Induced Attenuation) in the optical fiber (OF) is increased because of the color centers which deteriorate the transmission property and generate the absorption loss. In order to understand the radiation induced defect, Ion Beam induced luminescence (IBIL) was introduced to investigate it. IBIL technique is to analyze IR/VIS/UV luminescence related to ion beam interaction with outer shell electrons involved in chemical bonds and structure defects of target atoms. So IBIL is sensitive to its chemical composition and has been used in analysis of material characterization, geological samples and cultural heritage objects. In silica material, four O atoms are surrounding one Si atom in tetrahedral coordination. In this study, the influence of Copper (Cu) and Cerium (Ce) dopants to germano silica core optical fibers were investigated under proton irradiation at RBI using Ion Beam induced luminescence (IBIL) method. To understand the radiation induced defect of optical fibers, IBIL were tested to a germano-silica core fiber under 2 MeV proton irradiation. Although a Cu or Ce dopant was not detected by IBIL technique, the relation between the amount of radiation and luminescence can be established. This experiment showed a potential technique of studying the effects and behavior of additive elements for silica core fiber. To increase the radiation resistance of optical fibers, further investigations are needed, i. e. the proper additives and its contents and an interaction mechanism between Ge-related defects and additives.

  7. Radiation hardness of polysiloxane scintillators analyzed by ion beam induced luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, A., E-mail: quaranta@ing.unitn.i [University of Trento, Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali - DIMTI, Via Mesiano 77, I-38050 Povo, Trento (Italy); INFN, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Carturan, S. [Universita di Padova, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Marchi, T.; Antonaci, A. [INFN, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Scian, C. [Universita di Padova, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Kravchuk, V.L. [Universita di Bologna, Dipartimento di Fisica, Viale Carlo Berti Pichat 6, I-40127 Bologna (Italy); Degerlier, M.; Gramegna, F. [INFN, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Maggioni, G. [Universita di Padova, Laboratori Nazionali di Legnaro, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy)

    2010-10-01

    The radiation hardness of polysiloxane based scintillators has been measured by ion beam induced luminescence (IBIL). The light intensity as a function of the irradiation fluence with an He{sup +} beam at 1.8 MeV (1.0 {mu}A/cm{sup 2}) has been measured on undoped polymers synthesized with different amounts of phenyl units and on polysiloxanes doped with two different dye molecules (BBOT and Lumogen Violet) sensitizing the scintillation yield.

  8. An Ideal System for Analysis and Interpretation of Ion Beam Induced Luminescence

    Science.gov (United States)

    Townsend, P. D.; Crespillo, M. L.

    Luminescence is produced during ion beam implantation or ion-solid interaction for most insulators, and contains rich information. Surprisingly, the information extracted is often far from optimum. Rather than summarizing literature work, the focus here is to design an optimized and feasible target chamber that could offer far more information than what has currently been obtained. Such an improved and multi-probe approach opens a range of options to simultaneously record luminescence spectra generated by the ion beam, explore transient and excited state signals via probes of secondary excitation methods (such as ionisation or photo-stimulation). In addition, one may monitor optical absorption, reflectivity and lifetime dependent features, plus stress and polarization factors. A particularly valuable addition to conventional measurements is to have the ability to modulate both the ion beam and the probes. These features allow separation of transient lifetimes, as well as sensing intermediate steps in the defect formation and/or relaxation, and growth of new phases and nanoparticle inclusions. While luminescence methods are the most sensitive probes of defect and imperfection sites in optically active materials, less work has been performed at controlled low and high temperatures. Measurement with controlled cooling or heating of the samples is effective to reveal phase transitions (both of host and inclusions). Furthermore, simultaneous excitations (e.g. ions and photons) at different temperatures may lead to different end-phase or stale structure under extreme ionization conditions and enable fabrication of unique material structures. References to the existing literature will underline that the overall benefits of studying ion beam induced luminescence can be far more fruitful than that has normally been considered.

  9. Multivariate analysis of Ion Beam Induced Luminescence spectra of irradiated silver ion-exchanged silicate glasses

    Science.gov (United States)

    Valotto, Gabrio; Quaranta, Alberto; Cattaruzza, Elti; Gonella, Francesco; Rampazzo, Giancarlo

    A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag+-Na+ ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks.

  10. Recent developments of ion beam induced luminescence: radiation hardness study of thin film plastic scintillators

    Science.gov (United States)

    Quaranta, Alberto

    2005-10-01

    Ion beam induced luminescence (IBIL) measurements have been performed on thin film scintillators based on polyvinyltoluene (PVT) and 6FDA-DAD and BPDA-3F polyimides with H+ (1.85 MeV) and He+ (1.8-2.2 MeV) ion beams. The radiation hardness of the undoped polymers has been verified to depend mainly on the deposited energy density, polyimides exhibiting a higher resistance with respect to PVT. In PVT a new fluorescence band, attributed to the radical precursors of the network crosslinking, has been observed. The efficiency of doped polymers degradates with a higher rate, depending on the dye intrinsic lability. At high radiation fluences, the relative efficiency to NE102 of doped polyimides scintillators increases owing to the intrinsic host improved resistance.

  11. Investigation of chemical vapour deposition diamond detectors by X- ray micro-beam induced current and X-ray micro-beam induced luminescence techniques

    CERN Document Server

    Olivero, P; Vittone, E; Fizzotti, F; Paolini, C; Lo Giudice, A; Barrett, R; Tucoulou, R

    2004-01-01

    Tracking detectors have become an important ingredient in high-energy physics experiments. In order to survive the harsh detection environment of the Large Hadron Collider (LHC), trackers need to have special properties. They must be radiation hard, provide fast collection of charge, be as thin as possible and remove heat from readout electronics. The unique properties of diamond allow it to fulfill these requirements. In this work we present an investigation of the charge transport and luminescence properties of "detector grade" artificial chemical vapour deposition (CVD) diamond devices developed within the CERN RD42 collaboration, performed by means of X-ray micro-beam induced current collection (XBICC) and X-ray micro- beam induced luminescence (XBIL) techniques. XBICC technique allows quantitative estimates of the transport parameters of the material to be evaluated and mapped with micrometric spatial resolution. In particular, the high resolution and sensitivity of the technique has allowed a quantitati...

  12. Radiation damage mechanisms in CsI(Tl) studied by ion beam induced luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, Alberto [Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali - DIMTI, Universita di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy)], E-mail: quaranta@ing.unitn.it; Gramegna, Fabiana; Kravchuk, Vladimir [Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Scian, Carlo [Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali - DIMTI, Universita di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy)

    2008-06-15

    Ion beam induced luminescence (IBIL) has been used to study the kinetics of defect production under ion beam irradiation in CsI(Tl) crystals with different Tl{sup +} concentrations (250, 560, 3250 and 6500 ppm). The crystals have been irradiated with H{sup +} and {sup 4}He{sup +} at 1.8 MeV. Both the scintillator spectra after irradiation and the intensity decrease at different wavelengths as a function of the fluence have been measured. The emission bands shift to higher wavelengths after irradiation, and the light decrease has been interpolated following a saturation model for the point defect concentration. Crystals with low Tl{sup +} concentrations present the UV emission peak of pure CsI at 300 nm whose intensity during H{sup +} irradiation and reaches a maximum under He{sup +} irradiation. At low Tl{sup +} concentrations the damage rate depends on the ion stopping power, while at higher concentrations it depends on the activator concentration. The results can be interpreted by assuming that the defects affecting the light emission are point defects nearby Tl{sup +} ions.

  13. Fast reconstruction of a bounded ultrasonic beam using acoustically induced piezo-luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Kersemans, Mathias, E-mail: Mathias.Kersemans@UGent.be; Lammens, Nicolas; Degrieck, Joris; Van Paepegem, Wim [Mechanics of Materials and Structures MMS, Department of Materials Science and Engineering, Ghent University, Technologiepark 903, 9052 Zwijnaarde (Belgium); Smet, Philippe F. [LumiLab, Department of Solid State Sciences, Ghent University, Krijgslaan 281-S1, 9000 Gent (Belgium)

    2015-12-07

    We report on the conversion of ultrasound into light by the process of piezo-luminescence in epoxy with embedded BaSi{sub 2}O{sub 2}N{sub 2}:Eu as active component. We exploit this acoustically induced piezo-luminescence to visualize several cross-sectional slices of the radiation field of an ultrasonic piston transducer (f = 3.3 MHz) in both the near-field and the far-field. Simply combining multiple slices then leads to a fast representation of the 3D spatial radiation field. We have confronted the luminescent results with both scanning hydrophone experiments and digital acoustic holography results, and obtained a good correlation between the different approaches.

  14. Preliminary results on time-resolved ion beam induced luminescence applied to the provenance study of lapis lazuli

    Energy Technology Data Exchange (ETDEWEB)

    Czelusniak, C. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Palla, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Pisa and Università di Pisa, Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Massi, M. [Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Carraresi, L.; Giuntini, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Re, A.; Lo Giudice, A. [Dipartimento di Fisica, Università di Torino & INFN Sezione di Torino, Via Giuria 1, 10125 Torino (Italy); Pratesi, G. [Museo di Storia Naturale, Università di Firenze, Via G. La Pira 4, 50121 Firenze (Italy); Mazzinghi, A. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Ruberto, C. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 1, 50019 Sesto Fiorentino, Firenze (Italy); Castelli, L. [Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); and others

    2016-03-15

    This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3 MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430 nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

  15. Preliminary results on time-resolved ion beam induced luminescence applied to the provenance study of lapis lazuli

    Science.gov (United States)

    Czelusniak, C.; Palla, L.; Massi, M.; Carraresi, L.; Giuntini, L.; Re, A.; Lo Giudice, A.; Pratesi, G.; Mazzinghi, A.; Ruberto, C.; Castelli, L.; Fedi, M. E.; Liccioli, L.; Gueli, A.; Mandò, P. A.; Taccetti, F.

    2016-03-01

    This work will present preliminary results concerning the use of time-resolved ion beam induced luminescence applied to provenance studies of lapis lazuli. Measurements were performed at the pulsed beam facility at LABEC laboratory in Florence. Lapis lazuli is a semi-precious gemstone, used as ornament since the early civilizations that can be found in few places on Earth. The importance of this work lies in understanding the origin of various samples of lapis lazuli, from which it may be possible to gain insight into trade routes from ancient times. The samples studied in this work originated from Chile, Afghanistan, Tajikistan, Myanmar, and Siberia. The stones were irradiated with 3 MeV protons and the resulting luminescence was detected by a photomultiplier tube, whose output was acquired using a sampling digitizer VME module (CAEN/V1720). Wavelength discrimination was performed at 430 nm utilizing a range of beam currents. The results showed that, by changing the beam current intensity, one can study different features of lapis lazuli, and this may aid in distinguishing lapis lazuli from different provenances.

  16. In situ ion-beam-induced luminescence analysis for evaluating a micrometer-scale radio-photoluminescence glass dosimeter

    Science.gov (United States)

    Kawabata, Shunsuke; Kada, Wataru; Parajuli, Raj Kumar; Matsubara, Yoshinori; Sakai, Makoto; Miura, Kenta; Satoh, Takahiro; Koka, Masashi; Yamada, Naoto; Kamiya, Tomihiro; Hanaizumi, Osamu

    2016-06-01

    Micrometer-scale responses of radio-photoluminescence (RPL) glass dosimeters to focused ionized particle radiation were evaluated by combining ion-beam-induced luminescence (IBIL) and proton beam writing (PBW) using a 3 MeV focused proton microbeam. RPL phosphate glass dosimeters doped with ionic Ag or Cu activators at concentrations of 0.2 and 0.1% were fabricated, and their scintillation intensities were evaluated by IBIL spectroscopy under a PBW micropatterning condition. Compared with the Ag-doped dosimeter, the Cu-doped dosimeter was more tolerant of the radiation, while the peak intensity of its luminescence was lower, under the precise dose control of the proton microprobe. Proton-irradiated areas were successfully recorded using these dosimeters and their RPL centers were visualized under 375 nm ultraviolet light. The reproduction of the irradiated region by post-RPL imaging suggests that precise estimation of irradiation dose using microdosimeters can be accomplished by optimizing RPL glass dosimeters for various proton microprobe applications in organic material analysis and in micrometer-scale material modifications.

  17. SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

    CERN Document Server

    Gardés, E; Ban-d'Etat, B; Cassimi, A; Durantel, F; Grygiel, C; Madi, T; Monnet, I; Ramillon, J -M; Ropars, F; Lebius, H

    2013-01-01

    We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/\\mu m. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteri...

  18. SPORT: A new sub-nanosecond time-resolved instrument to study swift heavy ion-beam induced luminescence - Application to luminescence degradation of a fast plastic scintillator

    Science.gov (United States)

    Gardés, E.; Balanzat, E.; Ban-d'Etat, B.; Cassimi, A.; Durantel, F.; Grygiel, C.; Madi, T.; Monnet, I.; Ramillon, J.-M.; Ropars, F.; Lebius, H.

    2013-02-01

    We developed a new sub-nanosecond time-resolved instrument to study the dynamics of UV-visible luminescence under high stopping power heavy ion irradiation. We applied our instrument, called SPORT, on a fast plastic scintillator (BC-400) irradiated with 27-MeV Ar ions having high mean electronic stopping power of 2.6 MeV/μm. As a consequence of increasing permanent radiation damages with increasing ion fluence, our investigations reveal a degradation of scintillation intensity together with, thanks to the time-resolved measurement, a decrease in the decay constant of the scintillator. This combination indicates that luminescence degradation processes by both dynamic and static quenching, the latter mechanism being predominant. Under such high density excitation, the scintillation deterioration of BC-400 is significantly enhanced compared to that observed in previous investigations, mainly performed using light ions. The observed non-linear behaviour implies that the dose at which luminescence starts deteriorating is not independent on particles' stopping power, thus illustrating that the radiation hardness of plastic scintillators can be strongly weakened under high excitation density in heavy ion environments.

  19. Ion beam luminescence of Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Khanlary, M. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Department of Physics, Imam Khomeini International University, Qazvin, Iran (Iran, Islamic Republic of); Hole, D.E. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom); Townsend, P.D. [Science and Technology, Pevensey Building, University of Sussex, Brighton BN1 9QH (United Kingdom)]. E-mail: p.d.townsend@sussex.ac.uk

    2005-01-01

    Luminescence recorded during ion beam implantation of Nd:YAG has proved valuable in sensing structural and local crystal field changes caused by waveguide fabrication in this laser material. The relative line intensities from Nd are sensitive to excitation rate and so the spectra differ strongly between H{sup +} and H2+ excitation, with further changes in the examples using He{sup +} and N{sup +} ions. The overall intensities are reduced at lower temperatures, as well as showing variations in relative line patterns. Some suggestions of component lines and weak broad bands are offered in terms of trace rare earth and other impurities.

  20. Towards the differentiation of non-treated and treated corundum minerals by ion-beam-induced luminescence and other complementary techniques.

    Science.gov (United States)

    Calvo del Castillo, H; Deprez, N; Dupuis, T; Mathis, F; Deneckere, A; Vandenabeele, P; Calderón, T; Strivay, D

    2009-06-01

    Differentiation of treated and non-treated gemstones is a chief concern for major jewellery import companies. Low-quality corundum specimens coming from Asia appear to be often treated with heat, BeO or flux in order to enhance their properties as precious minerals. A set of corundum samples, rubies and sapphires from different origins, both treated and non-treated has been analysed at the Centre Européen d'Archéométrie, with ion-beam-induced luminescence (IBIL) and other complementary techniques such as Raman, proton-induced X-ray emission (PIXE), and proton-induced gamma-ray emission (PIGE). IBIL, also known as ionoluminescence, has been used before to detect impurities or defects inside synthetic materials and natural minerals; its use for the discrimination of gemstone simulants or synthetic analogues has been elsewhere discussed (Cavenago-Bignami Moneta, Gemología, Tomo I Piedras preciosas, perlas, corales, marfil. Ediciones Omega, Barcelona, 1991). PIXE has been frequently applied in the archaeometric field for material characterisation and provenance studies of minerals (Hughes, Ruby & sapphire. RWH Publishing, Fallbrook, 1997; Calvo del Castillo et al., Anal Bioanal Chem 387:869-878, 2007; Calligaro et al., NIM-B 189:320-327, 2002) and PIGE complements the elemental analysis by detecting light elements in these materials such as-and lighter than-sodium that cannot be identified with the PIXE technique (Sanchez et al., NIM-B 130:682-686, 1997; Emmett et al., Gems Gemology 39:84-135, 2003). The micro-Raman technique has also been used complementarily to ion beam analysis techniques for mineral characterisation (Novak et al., Appl Surf Sci 231-232:917-920, 2004). The aim of this study is to provide new means for systematic analysis of corundum gemstone-quality mineral, alternative to the traditional gemmologic methods; for this purpose, a Spanish jewellery import company supplied us with a number of natural corundum samples coming from different places

  1. Recent developments of ion beam induced luminescence at the external scanning microbeam facility of the LABEC laboratory in Florence

    Energy Technology Data Exchange (ETDEWEB)

    Colombo, E. [INFN sezione di Torino, via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica and Centro di Eccellenza NIS, Universita di Torino, via P. Giuria 1, 10125 Torino (Italy); Calusi, S. [INFN sezione di Torino, via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica, Universita and INFN Sez.di Firenze, via Sansone 1, 50019 Sesto Fiorentino, Firenze (Italy); Cossio, R. [Dipartimento di Scienze Mineralogiche e Petrologiche, via Valperga Caluso, 35, 10125 Torino (Italy); Giuntini, L. [Dipartimento di Fisica, Universita and INFN Sez.di Firenze, via Sansone 1, 50019 Sesto Fiorentino, Firenze (Italy); Giudice, A. [Dipartimento di Fisica and Centro di Eccellenza NIS, Universita di Torino, via P. Giuria 1, 10125 Torino (Italy); Lo Mando, P.A. [Dipartimento di Fisica, Universita and INFN Sez.di Firenze, via Sansone 1, 50019 Sesto Fiorentino, Firenze (Italy); Manfredotti, C. [INFN sezione di Torino, via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica and Centro di Eccellenza NIS, Universita di Torino, via P. Giuria 1, 10125 Torino (Italy); Massi, M.; Mirto, F.A. [Dipartimento di Fisica, Universita and INFN Sez.di Firenze, via Sansone 1, 50019 Sesto Fiorentino, Firenze (Italy); Vittone, E. [INFN sezione di Torino, via P.Giuria 1, 10125 Torino (Italy); Dipartimento di Fisica and Centro di Eccellenza NIS, Universita di Torino, via P. Giuria 1, 10125 Torino (Italy)], E-mail: vittone@to.infn.it

    2008-04-15

    A new ionoluminescence (IL) apparatus has been successfully installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC in Firenze; the apparatus for photon detection has been fully integrated in the existing ion beam analysis (IBA) set-up, for the simultaneous acquisition of IL and PIXE/PIGE/BS spectra and maps. The potential of the new set-up is illustrated in this paper by some results extracted by the analysis of art objects and advanced semiconductor materials. In particular, the adequacy of the new IBA set-up in the field of cultural heritage is pointed out by the coupled PIXE/IL micro-analysis of a lapis lazuli stone; concerning applications in material science, IL spectra from a N doped diamond sample were acquired and compared with CL analyses to evaluate the relevant sensitivities and the effect of ion damage.

  2. Recent developments of ion beam induced luminescence at the external scanning microbeam facility of the LABEC laboratory in Florence

    Science.gov (United States)

    Colombo, E.; Calusi, S.; Cossio, R.; Giuntini, L.; Giudice, A. Lo; Mandò, P. A.; Manfredotti, C.; Massi, M.; Mirto, F. A.; Vittone, E.

    2008-04-01

    A new ionoluminescence (IL) apparatus has been successfully installed at the external scanning microbeam facility of the 3 MV Tandetron accelerator of the INFN LABEC in Firenze; the apparatus for photon detection has been fully integrated in the existing ion beam analysis (IBA) set-up, for the simultaneous acquisition of IL and PIXE/PIGE/BS spectra and maps. The potential of the new set-up is illustrated in this paper by some results extracted by the analysis of art objects and advanced semiconductor materials. In particular, the adequacy of the new IBA set-up in the field of cultural heritage is pointed out by the coupled PIXE/IL micro-analysis of a lapis lazuli stone; concerning applications in material science, IL spectra from a N doped diamond sample were acquired and compared with CL analyses to evaluate the relevant sensitivities and the effect of ion damage.

  3. Lateral features of Cu(In{sub 0.7}Ga{sub 0.3})Se{sub 2}-heterodiodes in the {mu}m-scale by confocal luminescence and focused light beam induced currents

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, G.H. [Institute of Physics, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg (Germany)]. E-mail: g.h.bauer@uni-oldenburg.de; Guetay, L. [Institute of Physics, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg (Germany)

    2007-05-31

    Polycrystalline Cu(In,Ga)Se{sub 2} films (CIGSe) show substantial local variations of properties not only in regime of 10-100 nm but also in the scale length of few microns. We have analyzed optoelectronic properties of CIGSe heterodiodes by confocal luminescence and focused light beam induced currents (LBIC) versus temperature and excitation level with < 1 {mu}m lateral resolution and we observe a strong dependence of the size of local patterns on excitation flux and a considerable dependence of the yield and the spectral shape of luminescence and of microscopic LBI currents on temperature. From experiments we derive activation energies for rates of non-radiative recombination of (2-7) meV and for minority carrier mobilities of about (60-70) meV. These energies are compared with local variations of band edges resulting from potential fluctuations which are formulated after an approach from literature and which has been fitted to experimental shifts of PL peaks and squeezing of PL spectra versus excitation flux. We estimate tunnel barriers for radiative transitions of trapped electrons of about (30-70) meV. Correlating our different results we attribute the activation energy for minority transport in CIGSe reflecting local variations of the conduction band edge mainly to spatial fluctuations of the optical band gap as a consequence of spatially varying elemental composition, and to variations of splitting of the quasi-Fermi levels introduced by spatially varying defect densities.

  4. Proton induced luminescence of minerals

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H.; Millan, A.; Calderon, T. [Depto. Geologia y Geoquimica, Universidad Autonoma de Madrid, Ctra. Colmenar, km. 15, 28049, Madrid (Spain); Beneitez, P. [Departamento Quimica Fisica Aplicada, Universidad Autonoma de Madrid Cantoblanco, Madrid (Spain); Ruvalcaba S, J.L. [lFUNAM, Circuito de la lnvestigacion Cientifica s/n, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2008-07-01

    This paper presents a summary of Ionoluminescence (IL) for several minerals commonly found in jewellery pieces and/or artefacts of historical interest. Samples including silicates and non-silicates (native elements, halide, oxide, carbonate and phosphate groups) have been excited with a 1.8 MeV proton beam, and IL spectra in the range of 200- 900 nm have been collected for each one using a fiber optic coupled spectrometer. Light emissions have been related to Cr{sup 3+}, Mn{sup 2+} and Pr{sup 3+} ions, as well as intrinsic defects in these minerals. Results show the potential of IL for impurity characterization with high detection limits, local symmetry studies, and the study of the origin of minerals. (Author)

  5. Dehydration-induced luminescence in clay minerals

    Science.gov (United States)

    Coyne, L. M.; Lahav, N.; Lawless, J. G.

    1981-01-01

    Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

  6. Quantitative cone beam X-ray luminescence tomography/X-ray computed tomography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dongmei; Zhu, Shouping, E-mail: zhusp2009@gmail.com; Chen, Xueli; Chao, Tiantian; Cao, Xu; Zhao, Fengjun; Huang, Liyu; Liang, Jimin [Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education and School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China)

    2014-11-10

    X-ray luminescence tomography (XLT) is an imaging technology based on X-ray-excitable materials. The main purpose of this paper is to obtain quantitative luminescence concentration using the structural information of the X-ray computed tomography (XCT) in the hybrid cone beam XLT/XCT system. A multi-wavelength luminescence cone beam XLT method with the structural a priori information is presented to relieve the severe ill-posedness problem in the cone beam XLT. The nanophosphors and phantom experiments were undertaken to access the linear relationship of the system response. Then, an in vivo mouse experiment was conducted. The in vivo experimental results show that the recovered concentration error as low as 6.67% with the location error of 0.85 mm can be achieved. The results demonstrate that the proposed method can accurately recover the nanophosphor inclusion and realize the quantitative imaging.

  7. Luminescence effects of ion-beam bombardment of CdTe surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Olvera, J., E-mail: javier.olvera@uam.e [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Martinez, O. [Optronlab Group, Dpto. Fisica Materia Condensada, Edificio I-D, Universidad de Valladolid, Paseo de Belen 1, 47011 Valladolid (Spain); Plaza, J.L.; Dieguez, E. [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2009-09-15

    In the present work, we report the effect of low-energy ion bombardment on CdTe surfaces. The effect is revealed by FESEM images and photoluminescence (PL) measurements carried out before and after irradiation of CdTe polycrystals by means of an ion-beam sputtering (IBS) system. An important improvement in the luminescence of CdTe was observed in the irradiated areas, related to defect-free surfaces.

  8. Cone Beam X-ray Luminescence Computed Tomography Based on Bayesian Method.

    Science.gov (United States)

    Zhang, Guanglei; Liu, Fei; Liu, Jie; Luo, Jianwen; Xie, Yaoqin; Bai, Jing; Xing, Lei

    2017-01-01

    X-ray luminescence computed tomography (XLCT), which aims to achieve molecular and functional imaging by X-rays, has recently been proposed as a new imaging modality. Combining the principles of X-ray excitation of luminescence-based probes and optical signal detection, XLCT naturally fuses functional and anatomical images and provides complementary information for a wide range of applications in biomedical research. In order to improve the data acquisition efficiency of previously developed narrow-beam XLCT, a cone beam XLCT (CB-XLCT) mode is adopted here to take advantage of the useful geometric features of cone beam excitation. Practically, a major hurdle in using cone beam X-ray for XLCT is that the inverse problem here is seriously ill-conditioned, hindering us to achieve good image quality. In this paper, we propose a novel Bayesian method to tackle the bottleneck in CB-XLCT reconstruction. The method utilizes a local regularization strategy based on Gaussian Markov random field to mitigate the ill-conditioness of CB-XLCT. An alternating optimization scheme is then used to automatically calculate all the unknown hyperparameters while an iterative coordinate descent algorithm is adopted to reconstruct the image with a voxel-based closed-form solution. Results of numerical simulations and mouse experiments show that the self-adaptive Bayesian method significantly improves the CB-XLCT image quality as compared with conventional methods.

  9. Scattering-compensated cone beam x-ray luminescence computed tomography

    Science.gov (United States)

    Gao, Peng; Rong, Junyan; Pu, Huangsheng; Liu, Wenlei; Liao, Qimei; Lu, Hongbing

    2016-04-01

    X-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging with x-ray. It is a dual modality imaging technique based on the principle that some nanophosphors can emit near-infrared (NIR) light when excited by x-rays. The x-ray scattering effect is a great issue in both CT and XLCT reconstruction. It has been shown that if the scattering effect compensated, the reconstruction average relative error can be reduced from 40% to 12% in the in the pencil beam XLCT. However, the scattering effect in the cone beam XLCT has not been proved. To verify and reduce the scattering effect, we proposed scattering-compensated cone beam x-ray luminescence computed tomography using an added leading to prevent the spare x-ray outside the irradiated phantom in order to decrease the scattering effect. Phantom experiments of two tubes filled with Y2O3:Eu3+ indicated that the proposed method could reduce the scattering by a degree of 30% and can reduce the location error from 1.8mm to 1.2mm. Hence, the proposed method was feasible to the general case and actual experiments and it is easy to implement.

  10. A thermo-responsive supramolecular organogel: dual luminescence properties and luminescence conversion induced by Cd(2+).

    Science.gov (United States)

    Ma, Xinxian; Zhang, Jinjin; Tang, Ning; Wu, Jincai

    2014-12-14

    A simple dual luminescent acylhydrazone-functionalized benzimidazole derivative (L) was blended with ethylene glycol affording a thermo-responsive green-light-emitting supramolecular gel (G-gel). This G-gel can convert to a blue-light-emitting gel (B-gel) by strongly increasing the luminescence of the benzimidazole moiety upon addition of one equivalent of Cd(2+).

  11. Electron-beam irradiation effects on luminescence properties in subsurface regions of single-crystalline sapphires treated with and without hydrogen plasma exposures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bo-Hyun [Department of Electrical Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)]. E-mail: bhlee@daiyan.eei.eng.osaka-u.ac.jp; Ito, Toshimichi [Department of Electrical Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

    2007-10-15

    Electron irradiation effects on various insulating sapphires treated with and without hydrogen plasma have been investigated mainly by means of cathodoluminescence (CL) measurements. The samples examined included Be-diffusion-treated natural sapphire (BNS) and two types of synthetic sapphires grown by Verneuil and Czochralski methods. For all the samples examined, on one hand, their CL intensities of the F{sup +}-center-related emission peaked at {approx}3.8 eV rapidly increased with increasing the fluences of keV electrons, and were represented roughly by exponentially saturating curves. There occurred slight blue-shifts of the F{sup +}-center luminescence other than the intensity increases for some of the electron-irradiated specimens, suggesting possible presence of two components for the F{sup +}-center luminescence. On the other hand, a hydrogen plasma exposure to these sapphires resulted in sample-dependent changes in the optical property and in the beam-irradiation effect on the F{sup +}-center CL emission. Such variations were induced most strongly in the BNS sample, whose color changed from orange to pink due to substantial decreases in the absorbance after the hydrogen plasma treatment. Furthermore, the energy positions of both the Cr{sup 3+}-center luminescence peaked at {approx}1.8 eV and its satellite peaks were found to slightly shift for the untreated and H-plasma-treated BNS samples after the electron beam irradiations. Possible origins of these observations are discussed.

  12. Real-time optical-fibre luminescence dosimetry for radiotherapy: physical characteristics and applications in photon beams

    DEFF Research Database (Denmark)

    Aznar, M.C.; Andersen, C.E.; Bøtter-Jensen, L.;

    2004-01-01

    A new optical-fibre radiation dosimeter system, based on radioluminescence and optically stimulated luminescence from carbon-doped aluminium oxide, was developed and tested in clinical photon beams. This prototype offers several features, such as a small detector (1 x 1 x 2 mm), high sensitivity...

  13. Tunneling electron induced luminescence from porphyrin molecules on monolayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Feng; Kuang, Yanmin; Yu, Yunjie; Liao, Yuan; Zhang, Yao; Zhang, Yang; Dong, Zhenchao, E-mail: zcdong@ustc.edu.cn

    2015-01-15

    Using epitaxially grown graphene on Ru(0001) as a decoupling layer, we investigate the evolution of tunneling electron induced luminescence from different number of layers of porphyrin molecules. Light emission spectra and photon maps, acquired via a combined optical setup with scanning tunneling microscopy (STM), indicate that the electronic decoupling effect of a monolayer (ML) graphene alone is still insufficient for generating molecule-specific emission from both the 1st- and 2nd-layer porphyrin molecules. Nevertheless, interestingly, the plasmonic emission is enhanced for the 1st-layer but suppressed for the 2nd-layer in comparison with the plasmonic emission on the monolayer graphene. Intrinsic intramolecular molecular fluorescence occurs at the 3rd-layer porphyrin. Such molecular thickness is about two MLs thinner than previous reports where molecules were adsorbed directly on metals. These observations suggest that the monolayer graphene does weaken the interaction between molecule and metal substrate and contribute to the reduction of nonradiative decay rates. - Highlights: • Showing molecularly resolved photon maps of graphene and porphyrins on it. • Revealing the influence of spacer thickness on molecular electroluminescence. • Graphene does weaken the interaction between molecules and metal substrate.

  14. Laser-induced incandescence of suspended particles as a source of excitation of dye luminescence

    CERN Document Server

    Zelensky, S

    2003-01-01

    The interaction of pulsed YAG-Nd sup 3 sup + laser radiation with submicron light-absorbing particles suspended in an aqueous solution of Rhodamine 6G is investigated experimentally. The experiments demonstrate that the laser-induced incandescence of suspended particles excites the luminescence of the dissolved dye molecules. The mechanism of the luminescence excitation consists in the reabsorption of the thermal radiation within the volume of the sample cell. On the ground of this mechanism of excitation, a method of measurement of the luminescence quantum yield is proposed and realized. The method requires the knowledge of the geometrical parameters of the cell and does not require the use of reference samples.

  15. Quenching the radiation induced luminescence in quartz fibers under light monitoring

    CERN Document Server

    Demenkov, P V; Stepanov, V A; Stepanov, P A

    2002-01-01

    Measurements of the luminescence intensity in the optical fiber with the quartz glass core by the reactor pulsed irradiation in the visible range are carried out. Decrease in the intensity of the radiation-induced luminescence with growth of the sounding light intensity is determined by sounding the light guide by the laser radiation (the wave length of 532 and 632 nm). The decrease in the luminescence intensity takes place by the wave lengths greater, smaller or equal to the sounding light wave length

  16. Photomultiplier nonlinear response in time-domain laser-induced luminescence spectroscopy

    Directory of Open Access Journals (Sweden)

    Leandro José Bossy Schip

    2007-02-01

    Full Text Available A new procedure to find the limiting range of the photomultiplier linear response of a low-cost, digital oscilloscope-based time-resolved laser-induced luminescence spectrometer (TRLS, is presented. A systematic investigation on the instrument response function with different signal input terminations, and the relationship between the luminescence intensity reaching the photomultiplier and the measured decay time are described. These investigations establish that setting the maximum intensity of the luminescence signal below 0.3V guarantees, for signal input terminations equal or higher than 99.7 ohm, a linear photomultiplier response.

  17. Study on Water-Induced Ultra-Weak Luminescence Value of Wheat Kernels

    Directory of Open Access Journals (Sweden)

    Yitao Liang

    2013-09-01

    Full Text Available The wheat kernels were processed by moistened in water. The spontaneous and water-induced luminescence data (photon counts were noted with an ultra-weak luminescence (UWL detector. The following was the features of the data analyzed by the statistical parameters of the spontaneous luminescence and the fitting curves of the water-induced luminescence. The results show that the UWL intensity rises with the moistened time prolonged. It is concluded that the intensity depends on the moistened time mainly. If the moistened kernels owned a more porous structure, in the initial phase of imbibition, a higher UWL emission would be noted. Consequently, the further quantitative research of the relevant could lead a novel testing method about the wheat’s activity and quality.  

  18. The influence of the crystal structure on aggregation-induced luminescence of derivatives of aminobenzoic acid

    Science.gov (United States)

    Nosova, D. A.; Zarochentseva, E. P.; Vysotskaya, S. O.; Klemesheva, N. A.; Korotkov, V. I.

    2014-12-01

    The luminescence of three derivatives of 2-(phenylamino)-benzoic acid (N-phenylanthranilic, mefenamic, and niflumic acids) in benzene solution, in the polycrystalline state, and in the hexamethylbenzene matrix is studied. In the crystalline state, these compounds exhibit intense aggregation-induced luminescence. An increase in luminescence is also observed in the impurity crystal. The hexamethylbenzene crystal lattice restricts the mobility of molecules, thus ensuring the rigidity of the molecular structure of acids, which decreases the efficiency of nonradiative electron energy degradation. The main reason for the increase in the luminescence intensity in the case of fixation in a crystalline matrix is the formation of intramolecular hydrogen bonds and dimers of acid molecules.

  19. Luminescence of yttrium niobium-tantalate doubly activated by europium and/or terbium under X-ray and electron beam excitation

    Energy Technology Data Exchange (ETDEWEB)

    Arellano, I.D., E-mail: arellano@utp.edu.co [Department of Physics, Technological University of Pereira, Vereda La Julita, Pereira (Colombia); Nazarov, M.V. [Institute of Applied Physics, Academy of Sciences of Moldova, Republic of Moldova (Moldova, Republic of); School of Materials and Mineral Resources Engineering Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Cortes, J.A. [Department of Physics, Technological University of Pereira, Vereda La Julita, Pereira (Colombia); Ahmad Fauzi, M.N [School of Materials and Mineral Resources Engineering Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

    2012-09-15

    This paper reports the luminescence emission spectra of Y(Ta,Nb)O{sub 4} activated by rare earth ions such as Eu{sup 3+} and Tb{sup 3+}. The influence of these rare earth ions on the luminescence of yttrium niobium-tantalate phosphors was investigated. The luminescent properties were studied under X-ray and electron beam excitations. Under these excitations, the emission centers of the rare earth activators (Eu{sup 3+},Tb{sup 3+}) were found to contribute efficiently to the overall luminescence. Changing the mol concentration of the incorporated activators resulted in a broad variation of visible photoluminescence. Color cathodoluminescence images showed clearly the dependence of chromaticity on the different activators. With their various luminescence chromaticities, these rare earth activated phosphors are promising materials for solid-state lighting applications as well as for X-ray intensifying screens in medical diagnosis, providing a broad variation of visible photoluminescence from blue to red. - Highlights: Black-Right-Pointing-Pointer The Y(Ta,Nb)O{sub 4} phosphors were activated by rare earth ions such as Eu{sup 3+} and Tb{sup 3+}. Black-Right-Pointing-Pointer The phosphors were studied under X-ray and electron beam excitations. Black-Right-Pointing-Pointer The emission centers contribute efficiently to the overall luminescence. Black-Right-Pointing-Pointer Changing the concentration of the activators resulted in a broad luminescence.

  20. Radiation-induced luminescence in magnesium aluminate spinel crystals and ceramics

    Science.gov (United States)

    Gritsyna, V. T.; Kazarinov, Yu. G.; Kobyakov, V. A.; Reimanis, I. E.

    2006-09-01

    Radioluminescence (RL) and thermoluminescence (TL) in spinel crystals and ceramics were investigated to elucidate the radiation-induced electronic processes in single crystals grown by Verneuil and Czochralski methods as well as transparent and translucent ceramics. Both RL and TL spectra demonstrate a UV-band related to electron-hole recombination luminescence at intrinsic defects; green and red luminescence are identified with emission of Mn 2+- and Cr 3+-ions, respectively. The kinetics of growth of different RL luminescence bands depending on dose at the prolonged X-irradiation shows the competitive character of charge and energy transfer between defects and impurity ions. The dependence of RL intensity on the temperature of the sample was measured in the range of 300-750 K and compared with TL for different emission bands. The variety of maxima in the temperature dependence of RL and in the glow curves of TL measured for different luminescence bands in spinels of different origins and crystalline forms is used to show that charge carrier traps and luminescence centers are not isolated defects but are complexes of defects and impurities. The formation, structure and properties of these complexes depend on the processing conditions.

  1. Focused helium-ion-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Alkemade, P.F.A.; Miro, H. [Delft University of Technology, Kavli Institute of Nanoscience, Delft (Netherlands)

    2014-12-15

    The recent introduction of the helium ion microscope (HIM) offers new possibilities for materials modification and fabrication with spatial resolution below 10 nm. In particular, the specific interaction of He{sup +} ions in the tens of keV energy range with materials - i.e., minimal deflection and mainly energy loss via electronic excitations - renders the HIM a special tool for ion-beam-induced deposition. In this work, an overview is given of all studies of helium-ion-beam-induced deposition (He-IBID) that appeared in the literature before summer 2014. Continuum models that describe the deposition processes are presented in detail, with emphasis on precursor depletion and replenishment. In addition, a Monte Carlo model is discussed. Basic experimental He-IBID studies are critically examined. They show deposition rates of up to 0.1 nm{sup 3}/ion. Analysis by means of a continuum model yields the precursor diffusion constant and the cross sections for beam-induced precursor decomposition and beam-induced desorption. Moreover, it is shown that deposition takes place only in a small zone around the beam impact point. Furthermore, the characterization of deposited materials is discussed in terms of microstructure and resistivity. It is shown that He-IBID material resembles more electron-beam-induced-deposition (EBID) material than Ga-ion-beam-induced-deposition (Ga-IBID) material. Nevertheless, the spatial resolution for He-IBID is in general better than for EBID and Ga-IBID; in particular, proximity effects are minimal. (orig.)

  2. Simulation of beam-induced plasma for the mitigation of beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J.; Wang, G.; Samulyak, R.; Yu, K.; Litvinenko, V.

    2015-05-03

    One of the main challenges in the increase of luminosity of circular colliders is the control of the beam-beam effect. In the process of exploring beam-beam mitigation methods using plasma, we evaluated the possibility of plasma generation via ionization of neutral gas by proton beams, and performed highly resolved simulations of the beam-plasma interaction using SPACE, a 3D electromagnetic particle-in-cell code. The process of plasma generation is modelled using experimentally measured cross-section coefficients and a plasma recombination model that takes into account the presence of neutral gas and beam-induced electromagnetic fields. Numerically simulated plasma oscillations are consistent with theoretical analysis. In the beam-plasma interaction process, high-density neutral gas reduces the mean free path of plasma electrons and their acceleration. A numerical model for the drift speed as a limit of plasma electron velocity was developed. Simulations demonstrate a significant reduction of the beam electric field in the presence of plasma. Preliminary simulations using fully-ionized plasma have also been performed and compared with the case of beam-induced plasma.

  3. Geometric continuum mechanics and induced beam theories

    CERN Document Server

    R Eugster, Simon

    2015-01-01

    This research monograph discusses novel approaches to geometric continuum mechanics and introduces beams as constraint continuous bodies. In the coordinate free and metric independent geometric formulation of continuum mechanics as well as for beam theories, the principle of virtual work serves as the fundamental principle of mechanics. Based on the perception of analytical mechanics that forces of a mechanical system are defined as dual quantities to the kinematical description, the virtual work approach is a systematic way to treat arbitrary mechanical systems. Whereas this methodology is very convenient to formulate induced beam theories, it is essential in geometric continuum mechanics when the assumptions on the physical space are relaxed and the space is modeled as a smooth manifold. The book addresses researcher and graduate students in engineering and mathematics interested in recent developments of a geometric formulation of continuum mechanics and a hierarchical development of induced beam theories.

  4. Ag7+ ion induced modification of morphology, optical and luminescence behaviour of charge compensated CaMoO4 nanophosphor

    Science.gov (United States)

    Dutta, S.; Som, S.; Kunti, A. K.; Sharma, S. K.; Kumar, Vijay; Swart, H. C.; Visser, H. G.

    2016-10-01

    The present paper reports on the swift heavy ion (SHI) induced structural, optical and luminescence properties of CaMoO4:Dy3+/K+ nanophosphor synthesized via hydrothermal route. Herein 100 MeV Ag7+ ion beam was used varying fluence from 1 × 1011 to 1 × 1013 ions/cm2. The depth profile of the Ag7+ ions was estimated using SRIM code. XRD and FESEM results revealed the loss of crystallinity and reduction in particle size after SHI irradiations. The XPS technique confirmed the stability of oxidation states of the elements. Reflectance spectra exhibited a red shift in the absorption band, followed by a decrease in band gap. Decrease in the intensity of the photoluminescence peaks without any change in band positions was also obtained after ion irradiation. The thermoluminescence (TL) characteristics were discussed in detail, and the trapping parameter was calculated. The results were compared on the grounds of linear energy transfer of the irradiated ions.

  5. Induced focusing and conversion of a Gaussian beam into an elliptic Gaussian beam

    Indian Academy of Sciences (India)

    Manoj Mishra; Swapan Konar

    2005-09-01

    We have presented an investigation of the induced focusing in Kerr media of two laser beams, the pump beam and the probe beam, which could be either Gaussian or elliptic Gaussian or a combination of the two. We have used variational formalism to derive relevant beam-width equations. Among several important findings, the finding that a very week probe beam can be guided and focused when power of both beams are well below their individual threshold for self-focusing, is a noteworthy one. It has been found that induced focusing is not possible for laser beams of any wavelength and beam radius. In case both beams are elliptic Gaussian, we have shown that when power of both beams is above a certain threshold value then the effective radius of both beams collapses and collapse distance depends on power. Moreover, it has been found that induced focusing can be employed to convert a circular Gaussian beam into an elliptic Gaussian beam.

  6. Removing Noises Induced by Gamma Radiation in Cerenkov Luminescence Imaging Using a Temporal Median Filter

    Science.gov (United States)

    Li, Yang; Zhan, Yonghua; Kang, Fei; Wang, Jing

    2016-01-01

    Cerenkov luminescence imaging (CLI) can provide information of medical radionuclides used in nuclear imaging based on Cerenkov radiation, which makes it possible for optical means to image clinical radionuclide labeled probes. However, the exceptionally weak Cerenkov luminescence (CL) from Cerenkov radiation is susceptible to lots of impulse noises introduced by high energy gamma rays generating from the decays of radionuclides. In this work, a temporal median filter is proposed to remove this kind of impulse noises. Unlike traditional CLI collecting a single CL image with long exposure time and smoothing it using median filter, the proposed method captures a temporal sequence of CL images with shorter exposure time and employs a temporal median filter to smooth a temporal sequence of pixels. Results of in vivo experiments demonstrated that the proposed temporal median method can effectively remove random pulse noises induced by gamma radiation and achieve a robust CLI image. PMID:27648450

  7. Removing Noises Induced by Gamma Radiation in Cerenkov Luminescence Imaging Using a Temporal Median Filter

    Directory of Open Access Journals (Sweden)

    Xu Cao

    2016-01-01

    Full Text Available Cerenkov luminescence imaging (CLI can provide information of medical radionuclides used in nuclear imaging based on Cerenkov radiation, which makes it possible for optical means to image clinical radionuclide labeled probes. However, the exceptionally weak Cerenkov luminescence (CL from Cerenkov radiation is susceptible to lots of impulse noises introduced by high energy gamma rays generating from the decays of radionuclides. In this work, a temporal median filter is proposed to remove this kind of impulse noises. Unlike traditional CLI collecting a single CL image with long exposure time and smoothing it using median filter, the proposed method captures a temporal sequence of CL images with shorter exposure time and employs a temporal median filter to smooth a temporal sequence of pixels. Results of in vivo experiments demonstrated that the proposed temporal median method can effectively remove random pulse noises induced by gamma radiation and achieve a robust CLI image.

  8. Effect of acoustic, deformation on radiation-induced luminescence of pyrolytic boron nitride

    CERN Document Server

    Kardashev, B K; Plaksin, O A; Stepanov, V A; Stepanov, P A; Chernov, V M

    2001-01-01

    The effect of the ultrasound oscillations with the frequency of approximately 100 kHz on the radiation-induced luminescence on the pyrolytic boron nitride, originating by the protons irradiation (the energy of 8 MeV, the flux of 1.6 x 10 sup 1 sup 2 p/cm s), is studied. The impact of the ultrasound oscillations manifests itself by high deformation amplitudes (approximately 10 sup - sup 4), when the nonlinear, amplitude-dependent ultrasound absorption is observed. The obtained data are explained by the change in the kinetics of recrystallization, induced by irradiation, whereby the disappearance (radiation annealing) of the small angle boundaries occurs

  9. Pressure-induced luminescence of cerium-doped gadolinium gallium garnet crystal

    Science.gov (United States)

    Kaminska, A.; Duzynska, A.; Berkowski, M.; Trushkin, S.; Suchocki, A.

    2012-04-01

    Studies of the spectroscopic properties of Ce3+ dopant in bulk Gd3Ga5O12:Ce crystal under pressure are presented. In spite of strong intershell 4f→5d absorption bands at ambient pressure, the cerium luminescence in Gd3Ga5O12 is entirely quenched even at low temperature. It has been shown that applying pressure allows for recovery of the 5d→4f radiative transitions. Further increase of pressure improves the emission efficiency. This effect is analyzed in terms of two possible phenomena: (i) by pressure-induced electronic crossover of the excited 5d energy level of the Ce3+ with the conduction band bottom of the host crystal, and (ii) by decrease of electron-lattice coupling with increasing pressure, resulting in reduction of the Stokes shift and nonradiative transitions between the low vibrational levels of the 5d state and high vibrational levels of the ground 4f state. The results of high-pressure absorption and luminescence measurements point out that the ambient-pressure luminescence quenching is caused by the donor-like charge transfer processes due to the resonant location of the Ce3+ 5d electronic levels with respect to the host conduction band. In such a situation, the ionization of Ce3+ to Ce4+ occurs, accompanied by large lattice relaxation, which enables the nonradiative recombination to the Ce 4f state. The pressure-induced approach of the conduction-band bottom of the host crystal by the excited 5d energy level of the Ce3+ results in mixing between conduction band states and the 5d state, and the broadband luminescence from this mixed state is observed at pressures from 30 up to about 60 kbar. Then, for pressures exceeding 60 kbar, this luminescence is replaced by the classic Ce3+5d→4f transitions. Using a simple anticrossing model and configuration coordinate model in the appropriate pressure range, quantitative description of the system has been carried out, and the pressure-induced decrease of electron-lattice coupling has been shown.

  10. Determination of average LET of therapeutic proton beams using Al2O3:C optically stimulated luminescence (OSL) detectors.

    Science.gov (United States)

    Sawakuchi, Gabriel O; Sahoo, Narayan; Gasparian, Patricia B R; Rodriguez, Matthew G; Archambault, Louis; Titt, Uwe; Yukihara, Eduardo G

    2010-09-07

    In this work we present a methodology and proof of concept to experimentally determine average linear energy transfer (LET) of therapeutic proton beams using the optically stimulated luminescence (OSL) of small Al(2)O(3):C detectors. Our methodology is based on the fact that the shape of the OSL decay curve of Al(2)O(3):C detectors depends on the LET of the radiation field. Thus, one can use the shape of the OSL decay curves to establish an LET calibration curve, which in turn permits measurements of LET. We performed irradiations at the M D Anderson Cancer Center Proton Therapy Center, Houston (PTCH), with passive scattering beams. We determined the average LET of the passive scattering beams using a validated Monte Carlo model of the PTCH passive scattering nozzle and correlated them with the shape of the OSL decay curve to obtain an LET calibration curve. Using this calibration curve and OSL measurements, we determined the averaged LET at various water-equivalent depths for therapeutic spread-out Bragg peaks and compared the results with averaged LETs determined using the Monte Carlo simulations. Agreement between measured and simulated fluence-averaged LET was within 24% for low energy spread-out Bragg peak (SOBP) fields and within 14% for high energy SOBP fields. Agreement between measured and simulated dose-averaged LET was within 12% for low energy SOBP fields and within 47% for high energy SOBP fields. The data presented in this work demonstrated the correlation between the OSL decay curve shapes and the average LET of the radiation fields, providing proof of concept of the feasibility of using OSL from Al(2)O(3):C detectors to measure average LET of therapeutic proton beams.

  11. Cone beam x-ray luminescence computed tomography reconstruction with a priori anatomical information

    Science.gov (United States)

    Lo, Pei-An; Lin, Meng-Lung; Jin, Shih-Chun; Chen, Jyh-Cheng; Lin, Syue-Liang; Chang, C. Allen; Chiang, Huihua Kenny

    2014-09-01

    X-ray luminescence computed tomography (XLCT) is a novel molecular imaging modality that reconstructs the optical distribution of x-ray-excited phosphor particles with prior informational of anatomical CT image. The prior information improves the accuracy of image reconstruction. The system can also present anatomical CT image. The optical system based on a high sensitive charge coupled device (CCD) is perpendicular with a CT system. In the XLCT system, the xray was adopted to excite the phosphor of the sample and CCD camera was utilized to acquire luminescence emitted from the sample in 360 degrees projection free-space. In this study, the fluorescence diffuse optical tomography (FDOT)-like algorithm was used for image reconstruction, the structural prior information was incorporated in the reconstruction by adding a penalty term to the minimization function. The phosphor used in this study is Gd2O2S:Tb. For the simulation and experiments, the data was collected from 16 projections. The cylinder phantom was 40 mm in diameter and contains 8 mm diameter inclusion; the phosphor in the in vivo study was 5 mm in diameter at a depth of 3 mm. Both the errors were no more than 5%. Based on the results from these simulation and experimental studies, the novel XLCT method has demonstrated the feasibility for in vivo animal model studies.

  12. Characterization of Al2O3 optically stimulated luminescence films for 2D dosimetry using a 6 MV photon beam

    Science.gov (United States)

    Ahmed, M. F.; Shrestha, N.; Schnell, E.; Ahmad, S.; Akselrod, M. S.; Yukihara, E. G.

    2016-11-01

    This work evaluates the dosimetric properties of newly developed optically stimulated luminescence (OSL) films, fabricated with either Al2O3:C or Al2O3:C,Mg, using a prototype laser scanning reader, a developed image reconstruction algorithm, and a 6 MV therapeutic photon beam. Packages containing OSL films (Al2O3:C and Al2O3:C,Mg) and a radiochromic film (Gafchromic EBT3) were irradiated using a 6 MV photon beam using different doses, field sizes, with and without wedge filter. Dependence on film orientation of the OSL system was also tested. Diode-array (MapCHECK) and ionization chamber measurements were performed for comparison. The OSLD film doses agreed with the MapCHECK and ionization chamber data within the experimental uncertainties (response was approximately linear from the MDD up to a few grays (the linearity correction was  response, resolution and dosimetric properties. The negligible background and potential simple calibration make these OSLD films suitable for remote audits. The characterization presented here may motivate further commercial development of a 2D dosimetry system based on the OSL from Al2O3:C or Al2O3:C,Mg.

  13. Red luminescence from strain-induced GaInP quantum dots

    OpenAIRE

    1996-01-01

    The strain of self‐organized InP islands is used to induced quantum dots in near‐surface GaInP/AlGaInP quantum wells. To obtain quantum dotluminescence in a widely tunable wavelength range of 630–700 nm, the composition and thickness of the GaInP quantum well is varied. The effect of different cap layer materials, i.e., GaAs, AlGaAs, GaInP, and AlGaInP on the InP island formation and quantum dotluminescenceproperties is investigated. The luminescence intensity ratio of the quantum dot peak to...

  14. Analysis of beam loss induced abort kicker instability

    Energy Technology Data Exchange (ETDEWEB)

    Zhang W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Pai, C.; Tan, Y.

    2012-05-20

    Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

  15. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERAp beam-loss-monitor system

    Science.gov (United States)

    Wittenburg, Kay

    1994-06-01

    The beam-loss-monitors (BLMs) in the HERA-proton-ring (HERAp) must fulfill the following requirements: They have to measure losses sensitive and fast enough to prevent the superconducting magnets from beam loss induced quenching; the dynamic range of the monitors must exceed several decades in order to measure losses during beam lifetimes of hundreds of hours as well as the much stronger losses that may quench superconducting magnets; they have to be insensitive to the synchrotron radiation of the adjacent electron-ring (HERAe); and their radiation hardness must allow a monitor-lifetime of a few years of HERA operation. These requirements are well satisfied by the HERAp-BLM-System.

  16. Sensitive detection of PDT-induced cell damages with luminescent oxygen nanosensors

    Science.gov (United States)

    Ma, Hong-Ru; Peng, Hong-shang; You, Fang-tian; Ping, Jian-tao; Zhou, Chao; Guo, Lan-ying

    2016-09-01

    In this work luminescent nanosensors specifically created for intracellular oxygen (ic-O2) were utilized to assess photodynamic therapy (PDT) -induced cell damages. Firstly, ic-O2 was demonstrated to be consumed much faster than extracellular O2 with respective O2 nanosensors. Using the ic-O2 nanosensors, PDT-treated cells with different degree of impairment were then resolved according to the oxygen consumption rate (OCR). The evolving trend of cytotoxicity derived from OCRs was in agreement with cell viability obtained from 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Moreover, the direct damage of PDT on cell mitochondria was successfully detected by monitoring respiration instantly after PDT treatment, which is actually beyond the scope of MTT assay. These results suggest that fluorescence sensing of ic-O2-associated cell respiration is promising and even may become a standardized method, complementary to MTT assay, to evaluate PDT-induced cytotoxicity.

  17. Magnetic field induced optical vortex beam rotation

    CERN Document Server

    Shi, Shuai; Zhou, Zhi-Yuan; Li, Yan; Zhang, Wei; Shi, Bao-Sen

    2015-01-01

    Light with orbital angular momentum (OAM) has drawn a great deal of attention for its important applications in the fields of precise optical measurements and high capacity optical communications. Here we adopt a method to study the rotation of a light beam, which is based on magnetic field induced circular birefringence in warm 87Rb atomic vapor. The dependence of the rotation angle to the intensity of the magnetic field makes it appropriate for weak magnetic field measurement. We derive a detail theoretical description that is in well agreement with the experimental observations. The experiment shows here provides a new method for precise measurement of magnetic field intensity and expands the application of OAM-carrying light.

  18. Synthesis, Aggregation Induced Emission and Mechanochromic Luminescence of New β-Diketone Derivatives Bearing Tetraphenylene Moieties.

    Science.gov (United States)

    Shi, Haijie; Liu, Rui; Zhu, Senqiang; Gong, Qiqi; Shi, Hong; Zhu, Xiaolin; Zhu, Hongjun

    2016-11-01

    A series of β-diketone derivatives bearing tetraphenylene (TPE) moieties were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. All compounds exhibit broad absorption bands between 300 and 450 nm, which are assigned to the (1)π-π* transition of the conjugated system mixed intramolecular charge-transfer (ICT) transitions. Meanwhile, the emission of these compounds in solution at room temperature (λ em = 458 ~ 509 nm) can be attributed to the (1)π,π*/(1)ICT state. Introduction of freely rotatable TPE to conventional β-diketone luminophors quenches their light emissions in the solutions, but endows these molecules with aggregation-induced emission (AIE) characteristics in the condensed phase due to the restriction of intramolecular rotation. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these β-diketone derivatives can be tuned by the appended substituents, which would be useful for rational design of AIE compounds with high solid state luminescence performance. Furthermore, these AIE-active compounds exhibited distinct piezofluorochromic properties and switched reversibly upon grinding-fuming. Their photophysical properties have been investigated with the aim to provide a basis for elucidating the structure-property correlations and developing new multi-stimuli responsive luminescent materials.

  19. Focused electron beam induced deposition: A perspective

    Directory of Open Access Journals (Sweden)

    Michael Huth

    2012-08-01

    Full Text Available Background: Focused electron beam induced deposition (FEBID is a direct-writing technique with nanometer resolution, which has received strongly increasing attention within the last decade. In FEBID a precursor previously adsorbed on a substrate surface is dissociated in the focus of an electron beam. After 20 years of continuous development FEBID has reached a stage at which this technique is now particularly attractive for several areas in both, basic and applied research. The present topical review addresses selected examples that highlight this development in the areas of charge-transport regimes in nanogranular metals close to an insulator-to-metal transition, the use of these materials for strain- and magnetic-field sensing, and the prospect of extending FEBID to multicomponent systems, such as binary alloys and intermetallic compounds with cooperative ground states.Results: After a brief introduction to the technique, recent work concerning FEBID of Pt–Si alloys and (hard-magnetic Co–Pt intermetallic compounds on the nanometer scale is reviewed. The growth process in the presence of two precursors, whose flux is independently controlled, is analyzed within a continuum model of FEBID that employs rate equations. Predictions are made for the tunability of the composition of the Co–Pt system by simply changing the dwell time of the electron beam during the writing process. The charge-transport regimes of nanogranular metals are reviewed next with a focus on recent theoretical advancements in the field. As a case study the transport properties of Pt–C nanogranular FEBID structures are discussed. It is shown that by means of a post-growth electron-irradiation treatment the electronic intergrain-coupling strength can be continuously tuned over a wide range. This provides unique access to the transport properties of this material close to the insulator-to-metal transition. In the last part of the review, recent developments in mechanical

  20. Technology basis and perspectives on focused electron beam induced deposition and focused ion beam induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Rius, Gemma, E-mail: rius.gemma@nitech.ac.jp

    2014-12-15

    The main characteristics of focused electron beam induced deposition (FEBID) and focused ion beam induced deposition (FIBID) are presented. FEBID and FIBID are two nanopatterning techniques that allow the fabrication of submicron patterns with nanometer resolution on selected locations of any kind of substrate, even on highly structured supports. The process consists of mask less serial deposition and can be applied to a wide variety of materials, depending strictly on the precursor material source used. The basic mechanism of FEBID and FIBID is the adsorption of volatile precursor molecules onto the sample surface and decomposition of the molecules induced by the energetic electron and ion focused beams. The essential similarities of the two techniques are presented and especial emphasis is dedicated to highlighting their main differences, such as aspects related to resolution, deposition rate, deposits purity, substrate integrity, etc. In both cases, the factors interplay and complex mechanisms are still understood in a qualitative basis, so much work can still be done in terms of modeling and simulating the processes involved in FEBID and FIBID. Current work on FEBID and FIBID is presented through examples of achievements, interesting results and novel approaches.

  1. Amorphous track modelling of luminescence detector efficiency in proton and carbon beams

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, Leszek; Bassler, Niels

    be seriously hampered by variations in detector efficiency (light output per energy imparted) due to high-LET effects and gradients along the physical size (~mm) of the detector crystals. Amorphous track models (ATMs) such as the Ion-Gamma-Kill (IGK) approach by Katz and co-workers or the ECLaT code by Geiß et...... assumptions in a variety of detectors. The library also includes simple particle transportation or can be interfaced to external transport codes. We applied our code to RL and OSL data from fiber-coupled Al2O3:C-detectors in a proton (nominal energies 10 MeV to 60 MeV) and a carbon beam (270 MeV/u). Results...

  2. Piezoelectrically-induced stress-luminescence phenomenon in CaAl{sub 2}O{sub 4}:Eu{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yongbin [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Wu, Zheng, E-mail: wuzheng@zjnu.cn [College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004 (China); Jia, Yanmin, E-mail: ymjia@zjnu.edu.cn [Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Liu, Yongsheng [Department of Physics, Shanghai University of Electric Power, Shanghai 200090 (China)

    2015-10-15

    Piezoelectrically-induced stress-luminescence in the CaAl{sub 2}O{sub 4}:Eu{sup 2+} was investigated. Blue light that was visible to the naked eye could be observed in the dark when a pulse force of ∼7.7 kN was applied to the sample. The intensity of the stress-luminescence strongly depended on the magnitude of the applied force during a pulse cycle. The intensity decreased with repetitive application of pulse stress and was completely recovered after irradiation with ultraviolet light. It is suggested that the stress-luminescence effect in CaAl{sub 2}O{sub 4}:Eu{sup 2+} arises from the piezoelectrically-induced de-trapping of the charge carriers. A CaAl{sub 2}O{sub 4}:Eu{sup 2+} ceramic that exhibits a stress-luminescence effect has potential applications in smart stress optically-sensing devices. - Highlights: • The strong induced stress-luminescence in CaAl{sub 2}O{sub 4}:Eu{sup 2+} was observed. • The stress-luminescent intensity strongly depends on the magnitude of force. • The stress-luminescence could be completely recovered after the UV irradiation. • The strong stress-luminescent effect is potential in stress-light sensors.

  3. Characterization of Er{sub 2}O{sub 3} ceramic coatings by luminescence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T., E-mail: teru@nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Yoshino, M. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Hishinuma, Y. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Zhang, D. [School of Physical Sciences, The Graduate University for Advanced Studies, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Kada, W. [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki-shi, Gunma 370-1292 (Japan); Sato, F.; Iida, T. [Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871 (Japan); Nagasaki, T. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Muroga, T. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan)

    2011-10-01

    Cathodoluminescence and ion beam induced luminescence measurements were performed on Er{sub 2}O{sub 3} coatings fabricated by the Metal Organic Chemical Vapor Deposition (MOCVD), Metal Organic Decomposition (MOD) and RF sputtering methods to examine relations between luminescence spectra and their crystallinities. In luminescence spectra of all the measurements, peaks were observed in three bands of 380-420 nm, 530-580 nm and 640-690 nm. Cathodoluminescence intensities in the band of 640-690 nm increased with substrate temperatures in the fabrication processes and are considered to be significantly sensitive to the crystallinity. Change in luminescence spectra under ion beam irradiations also supported the relation. By using the relations between the spectra and crystallinities, luminescence measurements would be effective for nondestructive inspection and analysis of Er{sub 2}O{sub 3} coatings with a high spatial resolution.

  4. ZnO Luminescence and scintillation studied via photoexcitation, X-ray excitation, and gamma-induced positron spectroscopy.

    Science.gov (United States)

    Ji, J; Colosimo, A M; Anwand, W; Boatner, L A; Wagner, A; Stepanov, P S; Trinh, T T; Liedke, M O; Krause-Rehberg, R; Cowan, T E; Selim, F A

    2016-08-23

    The luminescence and scintillation properties of ZnO single crystals were studied by photoluminescence and X-ray-induced luminescence (XRIL) techniques. XRIL allowed a direct comparison to be made between the near-band emission (NBE) and trap emissions providing insight into the carrier recombination efficiency in the ZnO crystals. It also provided bulk luminescence measurements that were not affected by surface states. The origin of a green emission, the dominant trap emission in ZnO, was then investigated by gamma-induced positron spectroscopy (GIPS) - a unique defect spectroscopy method that enables positron lifetime measurements to be made for a sample without contributions from positron annihilation in the source materials. The measurements showed a single positron decay curve with a 175 ps lifetime component that was attributed to Zn vacancies passivated by hydrogen. Both oxygen vacancies and hydrogen-decorated Zn vacancies were suggested to contribute to the green emission. By combining scintillation measurements with XRIL, the fast scintillation in ZnO crystals was found to be strongly correlated with the ratio between the defect luminescence and NBE. This study reports the first application of GIPS to semiconductors, and it reveals the great benefits of the XRIL technique for the study of emission and scintillation properties of materials.

  5. ZnO Luminescence and scintillation studied via photoexcitation, X-ray excitation, and gamma-induced positron spectroscopy

    Science.gov (United States)

    Ji, J.; Colosimo, A. M.; Anwand, W.; Boatner, L. A.; Wagner, A.; Stepanov, P. S.; Trinh, T. T.; Liedke, M. O.; Krause-Rehberg, R.; Cowan, T. E.; Selim, F. A.

    2016-08-01

    The luminescence and scintillation properties of ZnO single crystals were studied by photoluminescence and X-ray-induced luminescence (XRIL) techniques. XRIL allowed a direct comparison to be made between the near-band emission (NBE) and trap emissions providing insight into the carrier recombination efficiency in the ZnO crystals. It also provided bulk luminescence measurements that were not affected by surface states. The origin of a green emission, the dominant trap emission in ZnO, was then investigated by gamma-induced positron spectroscopy (GIPS) - a unique defect spectroscopy method that enables positron lifetime measurements to be made for a sample without contributions from positron annihilation in the source materials. The measurements showed a single positron decay curve with a 175 ps lifetime component that was attributed to Zn vacancies passivated by hydrogen. Both oxygen vacancies and hydrogen-decorated Zn vacancies were suggested to contribute to the green emission. By combining scintillation measurements with XRIL, the fast scintillation in ZnO crystals was found to be strongly correlated with the ratio between the defect luminescence and NBE. This study reports the first application of GIPS to semiconductors, and it reveals the great benefits of the XRIL technique for the study of emission and scintillation properties of materials.

  6. Ligand induced circular dichroism and circularly polarized luminescence in CdSe quantum dots.

    Science.gov (United States)

    Tohgha, Urice; Deol, Kirandeep K; Porter, Ashlin G; Bartko, Samuel G; Choi, Jung Kyu; Leonard, Brian M; Varga, Krisztina; Kubelka, Jan; Muller, Gilles; Balaz, Milan

    2013-12-23

    Chiral thiol capping ligands L- and D-cysteines induced modular chiroptical properties in achiral cadmium selenide quantum dots (CdSe QDs). Cys-CdSe prepared from achiral oleic acid capped CdSe by postsynthetic ligand exchange displayed size-dependent electronic circular dichroism (CD) and circularly polarized luminescence (CPL). Opposite CPL signals were measured for the CdSe QDs capped with D- and L-cysteine. The CD profile and CD anisotropy varied with size of CdSe nanocrystals with largest anisotropy observed for CdSe nanoparticles of 4.4 nm. Magic angle spinning solid state NMR (MAS ssNMR) experiments suggested bidentate interaction between cysteine and the surface of CdSe. Time Dependent Density Functional Theory (TDDFT) calculations verified that attachment of L- and D-cysteine to the surface of model (CdSe)13 nanoclusters induces measurable opposite CD signals for the exitonic band of the nanocluster. The origin of the induced chirality is consistent with the hybridization of highest occupied CdSe molecular orbitals with those of the chiral ligand.

  7. Multi-electron beam system for high resolution electron beam induced deposition

    NARCIS (Netherlands)

    Van Bruggen, M.J.

    2008-01-01

    The development of a multi-electron beam system is described which is dedicated for electron beam induced deposition (EBID) with sub-10 nm resolution. EBID is a promising mask-less nanolithography technique which has the potential to become a viable technique for the fabrication of 20-2 nm structure

  8. Compensating tune spread induced by space charge in bunched beams

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.; Wang, G.

    2015-05-03

    The effects of space charge play a significant role in modern-day accelerators, frequently constraining the beam parameters attainable in an accelerator or in an accelerator chain. They also can limit the luminosity of hadron colliders operating either at low energies or with sub-TeV high-brightness hadron beams. The latter is applied for strongly cooled proton and ion beams in eRHIC – the proposed future electron-ion collider at Brookhaven National Laboratory. Using an appropriate electron beam would compensate both the tune shift and the tune spread in the hadron beam in a coasting beam. But these methods cannot compensate space charge tune spread in a bunched hadron beam. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with mismatched longitudinal velocity to compensate the space charge induced tune-shift and tune spread.

  9. Nanopillar growth by focused helium ion-beam-induced deposition

    NARCIS (Netherlands)

    Chen, P.; Veldhoven, E. van; Sanford, C.A.; Salemink, H.W.M.; Maas, D.J.; Smith, D.A.; Rack, P.D.; Alkemade, P.F.A.

    2010-01-01

    A 25 keV focused helium ion beam has been used to grow PtC nanopillars on a silicon substrate by beam-induced decomposition of a (CH3) 3Pt(CPCH3) precursor gas. The ion beam diameter was about 1 nm. The observed relatively high growth rates suggest that el

  10. Soft beams: When capillarity induces axial compression

    Science.gov (United States)

    Neukirch, S.; Antkowiak, A.; Marigo, J.-J.

    2014-01-01

    We study the interaction of an elastic beam with a liquid drop in the case where bending and extensional effects are both present. We use a variational approach to derive equilibrium equations and constitutive relation for the beam. This relation is shown to include a term due to surface energy in addition to the classical Young's modulus term, leading to a modification of Hooke's law. At the triple point where solid, liquid, and vapor phases meet, we find that the external force applied on the beam is parallel to the liquid-vapor interface. Moreover, in the case where solid-vapor and solid-liquid interface energies do not depend on the extension state of the beam, we show that the extension in the beam is continuous at the triple point and that the wetting angle satisfies the classical Young-Dupré relation.

  11. Testing beam-induced quench levels of LHC superconducting magnets

    Science.gov (United States)

    Auchmann, B.; Baer, T.; Bednarek, M.; Bellodi, G.; Bracco, C.; Bruce, R.; Cerutti, F.; Chetvertkova, V.; Dehning, B.; Granieri, P. P.; Hofle, W.; Holzer, E. B.; Lechner, A.; Nebot Del Busto, E.; Priebe, A.; Redaelli, S.; Salvachua, B.; Sapinski, M.; Schmidt, R.; Shetty, N.; Skordis, E.; Solfaroli, M.; Steckert, J.; Valuch, D.; Verweij, A.; Wenninger, J.; Wollmann, D.; Zerlauth, M.

    2015-06-01

    In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam-induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy deposition in the coils is compared to the quench levels predicted by electrothermal models, thus allowing one to validate and improve the models which are used to set beam-dump thresholds on beam-loss monitors for run 2.

  12. Helium ion beam induced growth of hammerhead AFM probes

    NARCIS (Netherlands)

    Nanda, G.; Veldhoven, E. van; Maas, D.J.; Sadeghian Marnani, H.; Alkemade, P.F.A.

    2015-01-01

    The authors report the direct-write growth of hammerhead atomic force microscope (AFM) probes by He+ beam induced deposition of platinum-carbon. In order to grow a thin nanoneedle on top of a conventional AFM probe, the authors move a focused He+ beam during exposure to a PtC precursor gas. In the f

  13. Electron beam induced oxidation of Al–Mg alloy surfaces

    NARCIS (Netherlands)

    Palasantzas, G.; Agterveld, D.T.L. van; Hosson, J.Th.M. De

    2002-01-01

    Electron beam currents of a few nanoamperes, currently used in nanometer scale scanning Auger/electron microscopy, induces severe oxidation of Al–Mg alloy surfaces at room temperature. Auger peak-to-peak oxygen curves for Al–Mg surfaces support the hypothesis that the electron beam creates additiona

  14. Delayed luminescence to monitor programmed cell death induced by berberine on thyroid cancer cells

    Science.gov (United States)

    Scordino, Agata; Campisi, Agata; Grasso, Rosaria; Bonfanti, Roberta; Gulino, Marisa; Iauk, Liliana; Parenti, Rosalba; Musumeci, Francesco

    2014-11-01

    Correlation between apoptosis and UVA-induced ultraweak photon emission delayed luminescence (DL) from tumor thyroid cell lines was investigated. In particular, the effects of berberine, an alkaloid that has been reported to have anticancer activities, on two cancer cell lines were studied. The FTC-133 and 8305C cell lines, as representative of follicular and anaplastic thyroid human cancer, respectively, were chosen. The results show that berberine is able to arrest cell cycle and activate apoptotic pathway as shown in both cell lines by deoxyribonucleic acid fragmentation, caspase-3 cleavage, p53 and p27 protein overexpression. In parallel, changes in DL spectral components after berberine treatment support the hypothesis that DL from human cells originates mainly from mitochondria, since berberine acts especially at the mitochondrial level. The decrease of DL blue component for both cell lines could be related to the decrease of intra-mitochondrial nicotinamide adenine dinucleotide and may be a hallmark of induced apoptosis. In contrast, the response in the red spectral range is different for the two cell lines and may be ascribed to a different iron homeostasis.

  15. Molecular characterization of microbial mutations induced by ion beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ichida, Hiroyuki [Graduate School of Science and Technology, Chiba University, Matsudo, Chiba 271-8510 (Japan); Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan)], E-mail: ichida@riken.jp; Matsuyama, Tomoki [Cellular Biochemistry Laboratory, Discovery Research Institute, RIKEN, Wako, Saitama 351-0198 (Japan); Ryuto, Hiromichi [Accelerator Operation Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Hayashi, Yoriko [Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Fukunishi, Nobuhisa [Accelerator Operation Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Abe, Tomoko [Accelerator Applications Research Group, Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198 (Japan); Koba, Takato [Graduate School of Science and Technology, Chiba University, Matsudo, Chiba 271-8510 (Japan)

    2008-03-01

    A positive selection system for gene disruption using a sucrose-sensitive transgenic rhizobium was established and used for the molecular characterization of mutations induced by ion beam irradiations. Single nucleotide substitutions, insertions, and deletions were found to occur in the sucrose sensitivity gene, sacB, when the reporter line was irradiated with highly accelerated carbon and iron ion beams. In all of the insertion lines, fragments of essentially the same sequence and of approximately 1188 bp in size were identified in the sacB regions. In the deletion lines, iron ions showed a tendency to induce larger deletions than carbon ions, suggesting that higher LET beams cause larger deletions. We found also that ion beams, particularly 'heavier' ion beams, can produce single gene disruptions and may present an effective alternative to transgenic approaches.

  16. Beam-induced quench test of LHC main quadrupole

    CERN Document Server

    Priebe, A; Dehning, B; Effinger, E; Emery, J; Holzer, E B; Kurfuerst, C; Nebot Del Busto, E; Nordt, A; Sapinski, M; Steckert, J; Verweij, A; Zamantzas, C

    2011-01-01

    Unexpected beam loss might lead to a transition of the accelerator superconducting magnet to a normal conducting state. The LHC beam loss monitoring (BLM) system is designed to abort the beam before the energy deposited in the magnet coils reach a quench-provoking level. In order to verify the threshold settings generated by simulation, a series of beam-induced quench tests at various beam energies has been performed. The beam losses are generated by means of an orbital bump peaked in one of main quadrupole magnets (MQ). The analysis includes not only BLM data but also the quench protection system (QPS) and cryogenics data. The measurements are compared to Geant4 simulations of energy deposition inside the coils and corresponding BLM signal outside the cryostat.

  17. Beam induced vacuum measurement error in BEPC II

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When the beam in BEPCII storage ring aborts suddenly, the measured pressure of cold cathode gauges and ion pumps will drop suddenly and decrease to the base pressure gradually. This shows that there is a beam induced positive error in the pressure measurement during beam operation. The error is the difference between measured and real pressures. Right after the beam aborts, the error will disappear immediately and the measured pressure will then be equal to real pressure. For one gauge, we can fit a non-linear pressure-time curve with its measured pressure data 20 seconds after a sudden beam abortion. From this negative exponential decay pumping-down curve, real pressure at the time when the beam starts aborting is extrapolated. With the data of several sudden beam abortions we have got the errors of that gauge in different beam currents and found that the error is directly proportional to the beam current, as expected. And a linear data-fitting gives the proportion coefficient of the equation, which we derived to evaluate the real pressure all the time when the beam with varied currents is on.

  18. In situ luminescence qualification of radiation damage in aluminas: F-aggregation and Al colloids

    Energy Technology Data Exchange (ETDEWEB)

    Malo, M., E-mail: marta.malo@ciemat.es; Moroño, A.; Hodgson, E.R.

    2014-10-15

    Highlights: •Correlation between IBIL and surface electrical degradation. •Potential to remotely monitor degradation of insulating materials. •Possibility for in situ recovery of the insulating properties by thermal annealing. -- Abstract: Recent work for in situ sequential measurement of ion beam induced luminescence and surface electrical conductivity has identified a correlation between surface electrical degradation and the luminescence for aluminas and sapphire during 45 keV He ion bombardment. Detailed measurements for the initial stages of degradation where rapid changes in the luminescence emission bands occur, have now identified processes related to oxygen vacancy (F centre) aggregation and aluminium colloid production as precursors to measurable surface electrical degradation in the irradiated region. This understanding enhances the possibility of using ion beam induced luminescence as a potential monitoring tool for material evolution and insulator surface degradation during irradiation, not only in ITER and future fusion devices, but also in present experimental reactor materials test programmes.

  19. Ion beam induced stress formation and relaxation in germanium

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, T., E-mail: Tobias.Steinbach@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany); Reupert, A.; Schmidt, E.; Wesch, W. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

    2013-07-15

    Ion irradiation of crystalline solids leads not only to defect formation and amorphization but also to mechanical stress. In the past, many investigations in various materials were performed focusing on the ion beam induced damage formation but only several experiments were done to investigate the ion beam induced stress evolution. Especially in microelectronic devices, mechanical stress leads to several unwanted effects like cracking and peeling of surface layers as well as changing physical properties and anomalous diffusion of dopants. To study the stress formation and relaxation process in semiconductors, crystalline and amorphous germanium samples were irradiated with 3 MeV iodine ions at different ion fluence rates. The irradiation induced stress evolution was measured in situ with a laser reflection technique as a function of ion fluence, whereas the damage formation was investigated by means of Rutherford backscattering spectrometry. The investigations show that mechanical stress builds up at low ion fluences as a direct consequence of ion beam induced point defect formation. However, further ion irradiation causes a stress relaxation which is attributed to the accumulation of point defects and therefore the creation of amorphous regions. A constant stress state is reached at high ion fluences if a homogeneous amorphous surface layer was formed and no further ion beam induced phase transition took place. Based on the results, we can conclude that the ion beam induced stress evolution seems to be mainly dominated by the creation and accumulation of irradiation induced structural modification.

  20. Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Borglin, Johan [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Guldbrand, Stina [Department of Physics, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Evenbratt, Hanne [Pharmaceutical Technology, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemigården 4, 412 96 Gothenburg (Sweden); Kirejev, Vladimir; Ericson, Marica B., E-mail: marica.ericson@chem.gu.se [Biomedical Photonics Group, Department of Chemistry and Molecular Biology, University of Gothenburg, Kemivägen 10, 412 96 Gothenburg (Sweden); Grönbeck, Henrik [Department of Applied Physics, Chalmers University of Technology, Kemivägen 9, 412 96 Gothenburg (Sweden)

    2015-12-07

    Gold nanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared (NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10 nm gold nanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that gold nanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region.

  1. Self-assembly of α-6T Molecule on Ag(100) and Related STM Induced Luminescence

    Institute of Scientific and Technical Information of China (English)

    Liu-guo Chen; Chao Zhang; Rui Zhang; Zhen-chao Dong

    2011-01-01

    We have investigated the self-assembly and light emission properties of organic αsexithiophene (α-6T) molecules on Ag(100) under different coverage by scanning tunneling microscopy (STM).At very low coverage,the α-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure.As the coverage is increased,α-6T molecules tend to pack side by side into a denser stripe structure.Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag(100)with the lower-layer stripe pattern serving as a template.Molecular fluorescence for α-6T molecules on Ag(100) at a coverage of five monolayers has been detected by light excitations,which indicates a well decoupled electronic states for the top-layer α-6T molecules.However,the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission.The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules.For intramolecular fluorescence to occur,the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.

  2. Testing beam-induced quench levels of LHC superconducting magnets

    CERN Document Server

    Auchmann, B; Bednarek, M; Bellodi, G; Bracco, C; Bruce, R; Cerutti, F; Chetvertkova, V; Dehning, B; Granieri, P P; Hofle, W; Holzer, E B; Lechner, A; Del Busto, E Nebot; Priebe, A; Redaelli, S; Salvachua, B; Sapinski, M; Schmidt, R; Shetty, N; Skordis, E; Solfaroli, M; Steckert, J; Valuch, D; Verweij, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2015-01-01

    In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with the top beam energies of 3.5 TeV and 4 TeV per proton (from 2012) instead of the nominal 7 TeV. The currents in the superconducting magnets were reduced accordingly. To date only seventeen beam-induced quenches have occurred; eight of them during specially designed quench tests, the others during injection. There has not been a single beam- induced quench during normal collider operation with stored beam. The conditions, however, are expected to become much more challenging after the long LHC shutdown. The magnets will be operating at near nominal currents, and in the presence of high energy and high intensity beams with a stored energy of up to 362 MJ per beam. In this paper we summarize our efforts to understand the quench levels of LHC superconducting magnets. We describe beam-loss events and dedicated experiments with beam, as well as the simulation methods used to reproduce the observable signals. The simulated energy depositio...

  3. Highly Nonlinear Luminescence Induced by Gold Nanoparticles on Glass Surfaces with Continuous-Wave Laser Illumination

    CERN Document Server

    Wu, Yong; Toro, Ligia; Stefani, Enrico

    2015-01-01

    We report on highly nonlinear luminescence being observed from individual spherical gold nanoparticles immobilized on a borosilicate glass surface and illuminated by continuous-wave (CW) lasers with relatively low power. The nonlinear luminescence shows optical super-resolution beyond the diffraction limit in three dimensions compared to the scatting of the excitation laser light. The luminescence intensity from most nanoparticles is proportional to the 5th--7th power of the excitation laser power and has wide excitation and emission spectra across the visible wavelength range. Strong nonlinear luminescence is only observed near the glass surface. High optical nonlinearity excited by low CW laser power is related to a long-lived dark state of the gold nanoparticles, where the excitation light is strongly absorbed. This phenomenon has potential biological applications in super-resolution and deep tissue imaging.

  4. Hard X-ray-induced optical luminescence via biomolecule-directed metal clusters.

    Science.gov (United States)

    Osakada, Yasuko; Pratx, Guillem; Sun, Conroy; Sakamoto, Masanori; Ahmad, Moiz; Volotskova, Olga; Ong, Qunxiang; Teranishi, Toshiharu; Harada, Yoshie; Xing, Lei; Cui, Bianxiao

    2014-04-07

    Here, we demonstrate that biomolecule-directed metal clusters are applicable in the study of hard X-ray excited optical luminescence, promising a new direction in the development of novel X-ray-activated imaging probes.

  5. Persistent luminescence induced by near infra-red photostimulation in chromium-doped zinc gallate for in vivo optical imaging

    Science.gov (United States)

    Sharma, Suchinder K.; Gourier, Didier; Teston, Eliott; Scherman, Daniel; Richard, Cyrille; Viana, Bruno

    2017-01-01

    The analysis of the optical spectroscopy of the Cr3+ doped spinel was initiated by Prof. Georges Boulon more than twenty years ago. More recently persistent luminescence nanoparticles of Cr doped zinc gallate have found interest for in vivo imaging of small animals. Here we evaluated near infra-red (NIR) excitation (or NIR photostimulation) via photo-transfer mechanism as an additional tool for in vivo optical imaging. Investigation of the persistent luminescence induced by NIR photostimulation is studied after either a primary UV (band-to-band excitation) or visible irradiation (direct Cr 3d-3d excitation). UV or visible pre-excited ZnGa2O4:Cr (ZGO:Cr) nanoparticles are kept active during several days thanks to deep traps (with depths 1 eV-1.2 eV) observed in these samples which can be probed through thermally stimulated luminescence (TSL) technique showing glow curve maximums at 470 K and 530 K upon visible light excitation. These deep traps are stable at room temperature but can be emptied by NIR light photostimulation. Experiments were carried out to study the photostimulation induced trapping-detrapping in the ZGO:Cr phosphor. Photostimulation was also tested in vivo for small animal optical imaging to offer new perspectives and modalities.

  6. Multi-electron beam system for high resolution electron beam induced deposition

    OpenAIRE

    Van Bruggen, M.J.

    2008-01-01

    The development of a multi-electron beam system is described which is dedicated for electron beam induced deposition (EBID) with sub-10 nm resolution. EBID is a promising mask-less nanolithography technique which has the potential to become a viable technique for the fabrication of 20-2 nm structures after 2013, as described by the International Technology Roadmap for Semiconductors (ITRS), or can be used for rapid prototyping in research applications. The key point is to combine the throughp...

  7. An efficient ionoluminescence analysis of turquoise gemstone as a weakly luminescent mineral.

    Science.gov (United States)

    Nikbakht, T; Kakuee, O; Lamehi-Rachti, M

    2017-02-21

    The unique ionization pattern of MeV-energy ion beam is applied for efficient luminescence analysis of a collection of natural turquoise samples. The considerable penetration depth of tens of micrometer and enhancement of energy deposition with depth, suggests ionoluminescence as an appropriate technique for studying weakly luminescent minerals. Herein, the luminescence induced in deeper parts of turquoise samples is extracted through their relatively transparent adjacent host stones. The resulting intense spectra reveal the vibrational structure of the broad green luminescence band of turquoise which probably originates from O2(-) centers. Moreover, owing to the applied ionoluminescence approach, red and blue luminescence bands of turquoise were observed which can be ascribed to Fe(3+) ions and UO2(2+) centers respectively. The elemental information of the samples is provided using micro-PIXE analysis technique.

  8. Beam-Induced Damage Mechanisms and their Calculation

    CERN Document Server

    Bertarelli, A

    2016-01-01

    The rapid interaction of highly energetic particle beams with matter induces dynamic responses in the impacted component. If the beam pulse is sufficiently intense, extreme conditions can be reached, such as very high pressures, changes of material density, phase transitions, intense stress waves, material fragmentation and explosions. Even at lower intensities and longer time-scales, significant effects may be induced, such as vibrations, large oscillations, and permanent deformation of the impacted components. These lectures provide an introduction to the mechanisms that govern the thermomechanical phenomena induced by the interaction between particle beams and solids and to the analytical and numerical methods that are available for assessing the response of impacted components. An overview of the design principles of such devices is also provided, along with descriptions of material selection guidelines and the experimental tests that are required to validate materials and components exposed to interactio...

  9. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    2011-01-01

    We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion......-effect on aerosol nucleation using a particle beam under conditions that resemble the Earth's atmosphere. By comparison with ionization using a gamma source we further show that the nature of the ionizing particles is not important for the ion-induced component of the nucleation. This implies that inexpensive...... ionization sources - as opposed to expensive accelerator beams - can be used for investigations of ion-induced nucleation....

  10. Stimulated luminescence of AlN ceramics induced by ultraviolet radiation

    DEFF Research Database (Denmark)

    Trinkler, L.; Bøtter-Jensen, L.; Christensen, P.

    2001-01-01

    Properties of thermally stimulated luminescence (TL) and optically stimulated luminescence (OSL) of the ceramic material A1N-Y2O3 have been studied after exposure to ultraviolet radiation (UVR). The dosemeter material Al2O3 : C has been used for comparative measurements. The spectral sensitivity...... than that of Al2O3 : C in a broad spectral region. The possibility of using A1N-Y2O3 ceramic for UVR dosimetry is discussed. (C) 2001 Elsevier Science Ltd. All rights reserved....

  11. Study of ion beam induced depolymerization using positron annihilation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Puglisi, O. E-mail: opuglisi@dipchi.unict.it; Fragala, M.E.; Lynn, K.G.; Petkov, M.; Weber, M.; Somoza, A.; Dupasquier, A.; Quasso, F

    2001-04-01

    Ion beam induced depolymerization of polymers is a special class of ion beam induced chemical reaction which gives rise to catastrophic 'unzipping' of macromolecules with production of large amounts of the monomer, of the order of many hundreds monomer molecules per each macromolecule. The possible modification of the density at microscopic level prompted us to undertake a study of this effect utilizing positron annihilation techniques in Poly(methylmethacrylate) (PMMA) before and after bombardment with He{sup +} 300 keV ions at 200 deg. C. Preliminary results shown here indicate that before bombardment there is a reproducible dependence of nano-hole distribution on the sample history. Moreover at 200 deg. C we do not detect formation of new cavities as a consequence of the strong depolymerization that occurs under the ion beam. The possible correlation of these findings with transport properties of PMMA at temperature higher than the glass transition temperature will be discussed.

  12. Proximity effect in ion-beam-induced deposition of nanopillars

    NARCIS (Netherlands)

    Chen, P.; Salemink, H.W.M.; Alkemade, P.F.A.

    2009-01-01

    Ion-beam-induced deposition (IBID) is a powerful technique for prototyping three-dimensional nanostructures. To study its capability for this purpose, the authors investigate the proximity effect in IBID of nanopillars. In particular, the changes in shape and dimension of pillars are studied when a

  13. Fabrication of plasmonic nanostructures with electron beam induced deposition

    NARCIS (Netherlands)

    Acar, H.

    2013-01-01

    The work described in this thesis was shaped by the goal---coming up new approaches to fabricate plasmonic materials with electron beam induced deposition (EBID). One-step, bottom-up and direct-write are typical adjectives that are used to indicate the advantageous properties of this technique. Thes

  14. Gold ion beams induced desorption studies for Booster Nuclotron

    Science.gov (United States)

    Kuznetsov, A. B.; Tuzikov, A. V.; Philippov, A. V.

    2016-12-01

    Heavy ions induced pressure rise is one of the machine limits. The calculation results of the gold ion beam 197Au31+ losses due to residual gas interaction in view of desorption of adsorbed particles on the Booster Nuclotron vacuum chamber surface are discussed.

  15. Radiation-induced growth and isothermal decay of infrared-stimulated luminescence from feldspar

    DEFF Research Database (Denmark)

    Guralnik, Benny; Li, Bo; Jain, Mayank

    2015-01-01

    Optically stimulated luminescence (OSL) ages can determine a wide range of geological events or processes, such as the timing of sediment deposition, the exposure duration of a rock surface, or the cooling rate of bedrock. The accuracy of OSL dating critically depends on our capability to describ...

  16. Optimizing Electromagnetically Induced Transparency Signals with Laguerre-Gaussian Beams

    Science.gov (United States)

    Holtfrerich, Matthew; Akin, Tom; Krzyzewski, Sean; Marino, Alberto; Abraham, Eric

    2016-05-01

    We have performed electromagnetically induced transparency in ultracold Rubidium atoms using a Laguerre-Gaussian laser mode as the control beam. Laguerre-Gaussian modes are characterized by a ring type transverse intensity profile and carry intrinsic orbital angular momentum. This angular momentum carried by the control beam can be utilized in optical computing applications which is unavailable to the more common Gaussian laser field. Specifically, we use a Laguerre-Gaussian control beam with a Gaussian probe to show that the linewidth of the transmission spectrum can be narrowed when compared to a Gaussian control beam that has the same peak intensity. We present data extending this work to compare control fields in both the Gaussian and Laguerre-Gaussian modes with constant total power. We have made efforts to find the optical overlap that best minimizes the transmission linewidth while also maintaining signal contrast. This was done by changing the waist size of the control beam with respect to the probe. The best results were obtained when the waist of a Laguerre-Gaussian control beam is equal to the waist of the Gaussian probe resulting in narrow linewidth features.

  17. Luminescence nanothermometry

    Science.gov (United States)

    Jaque, Daniel; Vetrone, Fiorenzo

    2012-07-01

    The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

  18. Limits for Beam-Induced Damage: Reckless or too Cautious?

    CERN Document Server

    Bertarelli, A; Carra, F; Cerutti, F; Dallocchio, A; Mariani, N; Peroni, L; Scapin, M

    2011-01-01

    Accidental events implying direct beam impacts on collimators are of the utmost importance as they may lead to serious limitations of the overall LHC Performance. In order to assess damage threshold of components impacted by high energy density beams, entailing changes of phase and extreme pressures, state-of-the-art numerical simulation methods are required. In this paper, a review of the different dynamic response regimes induced by particle beams is given along with an indication of the most suited tools to treat each regime. Particular attention is paid to the most critical case, that of shock waves, for which standard Finite Element codes are totally unfit. A novel category of numerical tools, named Hydrocodes, has been adapted and used to analyse the consequences of an asynchronous beam abort on Phase 1 Tertiary Collimators (TCT). A number of simulations has been carried out with varying beam energy, number of bunches and bunch sizes allowing to identify different damage levels for the TCT up to catastr...

  19. Limits for Beam Induced Damage: Reckless or too Cautious?

    CERN Document Server

    Bertarelli, A; Carra, F; Cerutti, F; Dallocchio, A; Mariani, N; Peroni, L; Scapin, M

    2011-01-01

    Accidental events implying direct beam impacts on collimators are of the utmost importance as they may lead to serious limitations of the overall LHC Performance. In order to assess damage threshold of components impacted by high energy density beams, entailing changes of phase and extreme pressures, state-of-the-art numerical simulation methods are required. In this paper, a review of the different dynamic response regimes induced by particle beams is given along with an indication of the most suited tools to treat each regime. Particular attention is paid to the most critical case, that of shock waves, for which standard Finite Element codes are totally unfit. A novel category of numerical tools, named Hydrocodes, has been adapted and used to analyse the consequences of an asynchronous beam abort on Phase 1 Tertiary Collimators (TCT). A number of simulations has been carried out with varying beam energy, number of bunches and bunch sizes allowing to identify different damage levels for the TCT up to catastr...

  20. Electron beam induced surface activation of oxide surfaces for nanofabrication

    Energy Technology Data Exchange (ETDEWEB)

    Vollnhals, Florian; Seiler, Steffen; Walz, Marie-Madeleine; Steinrueck, Hans-Peter; Marbach, Hubertus [Lehrstuhl fuer Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen (Germany); Woolcot, Tom; Thornton, Geoff [London Centre for Nanotechnology and Department of Chemistry, University College London (United Kingdom)

    2012-07-01

    The controlled fabrication of structures on the nanoscale is a major challenge in science and engineering. Direct-write techniques like Electron Beam Induced Deposition (EBID) were shown to be suitable tools in this context. Recently, Electron Beam Induced Surface Activation (EBISA) has been introduced as a new focused electron beam technique. In EBISA, a surface, e.g. SiO{sub 2}, is irradiated by a focused electron beam, resulting in an activation of the exposed area. The activated area can then react and decompose precursor gases like iron pentacarbonyl, Fe(CO){sub 5}. This leads to a primary deposit, which continues to grow autocatalytically as long as Fe(CO){sub 5} is supplied, resulting in pure (> 90 % at.), crystalline iron nanostructures. We expand the use of this concept by exploring EBISA to produce metallic nanostructures on TiO{sub 2}(110) in UHV; atomistic insight into the process is obtained via Scanning Tunneling Microscopy (STM) and chemical insight via Auger Electron Spectroscopy (AES).

  1. (d,p)-transfer induced fission of heavy radioactive beams

    CERN Document Server

    Veselsky, Martin

    2012-01-01

    (d,p)-transfer induced fission is proposed as a tool to study low energy fission of exotic heavy nuclei. Primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission offers a possibility for systematic study the low energy fission of heavy exotic nuclei at the ISOLDE.

  2. Alloying of metal nanoparticles by ion-beam induced sputtering

    Science.gov (United States)

    Magudapathy, P.; Srivastava, S. K.; Gangopadhyay, P.; Amirthapandian, S.; Saravanan, K.; Das, A.; Panigrahi, B. K.

    2017-01-01

    Ion-beam sputtering technique has been utilized for controlled synthesis of metal alloy nanoparticles of compositions that can be tuned. Analysis of various experimental results reveals the formation of Ag-Cu alloy nanoparticles on a silica substrate. Surface-plasmon optical resonance positions and observed shifts of Ag Bragg angles in X-ray diffraction pattern particularly confirm formation of alloy nanoparticles on glass samples. Sputtering induced nano-alloying mechanism has been discussed and compared with thermal mixing of Ag and Cu thin films on glass substrates. Compositions and sizes of alloy nanoparticles formed during ion-beam induced sputtering are found to exceed far from the values of thermal mixing.

  3. Luminescence Instrumentation

    DEFF Research Database (Denmark)

    Jain, Mayank; Bøtter-Jensen, Lars

    2014-01-01

    This chapter gives an introduction to instrumentation for stimulated luminescence studies, with special focus on luminescence dating using the natural dosimeters, quartz and feldspars. The chapter covers basic concepts in luminescence detection, and thermal and optical stimulation, and reference...... irradiation. It then briefly describes development of spectrometers in dating applications, and finally gives an overview of recent development in the field directly linked to novel instrumentation. Contents of Paper...

  4. (AEDPH3)·(BtaH): a novel supramolecular plaster with formaldehyde adsorption and formaldehyde/ultraviolet ray-induced luminescence switching performance.

    Science.gov (United States)

    Chen, Shuo-ping; Hu, Le; Zhang, Yu-qin; Deng, Pu; Li, Cong; Chen, Xi; Yuan, Liang-jie

    2012-01-14

    A novel supramolecular plaster, (AEDPH(3))·(BtaH) (1), is synthesised and characterized. The supramolecular plaster is easy to synthesise and process, and displays good mechanical properties. It can adsorb and eliminate formaldehyde (HCHO) with high efficiency and exhibits very interesting HCHO/ultraviolet ray-induced luminescence switching.

  5. Theoretical modeling on the laser induced effect of liquid crystal optical phased beam steering

    Science.gov (United States)

    He, Xiaoxian; Wang, Xiangru; Wu, Liang; Tan, Qinggui; Li, Man; Shang, Jiyang; Wu, Shuanghong; Huang, Ziqiang

    2017-01-01

    Non-mechanical laser beam steering has been reported previously in liquid crystal array devices. To be one of the most promising candidates to be practical non-mechanical laser deflector, its laser induced effect still has few theoretical model. In this paper, we propose a theoretical model to analyze this laser induced effect of LC-OPA to evaluate the deterioration on phased beam steering. The model has three parts: laser induced thermal distribution; temperature dependence of material parameters and beam steering deterioration. After these three steps, the far field of laser beam is obtained to demonstrate the steering performance with the respect to the incident laser beam power and beam waist.

  6. On second harmonic generation and multiphoton-absorption induced luminescence from laser-reshaped silver nanoparticles embedded in glass

    Science.gov (United States)

    Zolotovskaya, S. A.; Tyrk, M. A.; Stalmashonak, A.; Gillespie, W. A.; Abdolvand, A.

    2016-10-01

    Spherical silver nanoparticles (NPs) of 30 nm diameter embedded in soda-lime glass were uniformly reshaped (elongated) after irradiation by a linearly polarised 250 fs pulsed laser operating within the NPs’ surface plasmon resonance band. We observed second harmonic generation (SHG) and multiphoton-absorption-induced luminescence (MAIL) in the embedded laser-reshaped NPs upon picosecond (10 ps) pulsed laser excitation at 1064 nm. A complementary study of SHG and MAIL was conducted in soda-lime glass containing embedded, mechanically-reshaped silver NPs of a similar elongation ratio (aspect ratio) to the laser-reshaped NPs. This supports the notion that the observed difference in SHG and MAIL in the studied nanocomposite systems is due to the shape modification mechanism. The discrete dipole approximation method was used to assess the absorption and scattering cross-sections of the reshaped NPs with different elongation ratios.

  7. On second harmonic generation and multiphoton-absorption induced luminescence from laser-reshaped silver nanoparticles embedded in glass.

    Science.gov (United States)

    Zolotovskaya, S A; Tyrk, M A; Stalmashonak, A; Gillespie, W A; Abdolvand, A

    2016-10-28

    Spherical silver nanoparticles (NPs) of 30 nm diameter embedded in soda-lime glass were uniformly reshaped (elongated) after irradiation by a linearly polarised 250 fs pulsed laser operating within the NPs' surface plasmon resonance band. We observed second harmonic generation (SHG) and multiphoton-absorption-induced luminescence (MAIL) in the embedded laser-reshaped NPs upon picosecond (10 ps) pulsed laser excitation at 1064 nm. A complementary study of SHG and MAIL was conducted in soda-lime glass containing embedded, mechanically-reshaped silver NPs of a similar elongation ratio (aspect ratio) to the laser-reshaped NPs. This supports the notion that the observed difference in SHG and MAIL in the studied nanocomposite systems is due to the shape modification mechanism. The discrete dipole approximation method was used to assess the absorption and scattering cross-sections of the reshaped NPs with different elongation ratios.

  8. Radiation Damage Mechanisms for Luminescence in Eu-doped GaN

    Energy Technology Data Exchange (ETDEWEB)

    Tringe, J W; Castelaz, J M; Felter, T E; Wetzel, C; Talley, C E; Morse, J D; Stevens, C G

    2005-11-01

    Thin films of Eu-doped GaN are irradiated with 500 keV He{sup +} ions to understand radiation damage mechanisms and to quantify luminescence efficiency. Ion beam induced luminescence was monitored spectroscopically as function of fluence. Behavior observed is consistent with simultaneous creation of non-radiative defects and destruction of luminescent centers associated with the 4f-4f core-level transition in Eu{sup 3+}. This model contrasts with a previous description which takes into account only non-radiative defect generation in GaN:Eu. Based on light from a BaF{sub 2} scintillator standard, the luminescent energy generation efficiency of GaN:Eu films doped to {approx}3 x 10{sup 18} cm{sup -3} Eu is estimated to be {approx}0.1%.

  9. Focused Ion Beam Induced Effects on MOS Transistor Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Abramo, Marsha T.; Antoniou, Nicholas; Campbell, Ann N.; Fleetwood, Daniel M.; Hembree, Charles E.; Jessing, Jeffrey R.; Soden, Jerry M.; Swanson, Scot E.; Tangyunyong, Paiboon; Vanderlinde, William E.

    1999-07-28

    We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.

  10. Semiconductor characterization by scanning ion beam induced charge (IBIC) microscopy

    CERN Document Server

    Vittone, E; Olivero, P; Manfredotti, C; Jaksic, M; Giudice, A Lo; Fizzotti, F; Colombo, E

    2016-01-01

    The acronym IBIC (Ion Beam Induced Charge) was coined in early 1990's to indicate a scanning microscopy technique which uses MeV ion beams as probes to image the basic electronic properties of semiconductor materials and devices. Since then, IBIC has become a widespread analytical technique to characterize materials for electronics or for radiation detection, as testified by more than 200 papers published so far in peer-reviewed journals. Its success stems from the valuable information IBIC can provide on charge transport phenomena occurring in finished devices, not easily obtainable by other analytical techniques. However, IBIC analysis requires a robust theoretical background to correctly interpret experimental data. In order to illustrate the importance of using a rigorous mathematical formalism, we present in this paper a benchmark IBIC experiment aimed to test the validity of the interpretative model based on the Gunn's theorem and to provide an example of the analytical capability of IBIC to characteriz...

  11. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    atmospheric conditions using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear and significant contribution from ion induced nucleation and consider this to be an unambiguous observation of the ion-effect on aerosol nucleation using a particle beam under conditions not far......The effect of ions in aerosol nucleation is a subject where much remains to be discovered. That ions can enhance nucleation has been shown by theory, observations, and experiments. However, the exact mechanism still remains to be determined. One question is if the nature of the ionization affects...... the nucleation. This is an essential question since many experiments have been performed using radioactive sources that ionize differently than the cosmic rays which are responsible for the majority of atmospheric ionization. Here we report on an experimental study of sulphuric acid aerosol nucleation under near...

  12. Capillary-force-induced formation of luminescent polystyrene/(rare-earth-doped nanoparticle) hybrid hollow spheres.

    Science.gov (United States)

    Chen, Min; Xie, Lin; Li, Fuyou; Zhou, Shuxue; Wu, Limin

    2010-10-01

    This paper presents a "one-pot" procedure to synthesize polystyrene/(rare-earth-doped nanoparticles) (PS/REDNPs) hybrid hollow spheres via the in situ diffusion of organic core into inorganic shell under strong capillary force. In this approach, when carboxyl-capped PS colloids were deposited by different REDNPs in aqueous medium, such as LaF3:Eu3+, LaF3:Ce3+-Tb3+, and YVO4:Dy3+, PS/REDNPs inorganic-organic hybrid hollow spheres could be directly obtained via the in situ diffusion of core PS chains into the voids between rare-earth-doped nanoparticles through the strong capillary force. Not only is the synthetic procedure versatile and very simple, but also the obtained hybrid hollow spheres are hydrophilic and luminescent and could be directly used in chemical and biological fields.

  13. Volume changes in glass induced by an electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Gavenda, Tadeáš, E-mail: gavendat@vscht.cz [Department of Glass and Ceramics, Institute of Chemical Technology, Technická 5, CZ-166 28 Prague (Czech Republic); Gedeon, Ondrej [Department of Glass and Ceramics, Institute of Chemical Technology, Technická 5, CZ-166 28 Prague (Czech Republic); Jurek, Karel [Institute of Physics, Academy of the Czech Republic, Na Slovance 2, CZ-182 21 Prague (Czech Republic)

    2014-03-01

    Three glasses (float, borosilicate float and Schott D263 glasses) were irradiated by 50 keV electron beams with doses within the range of 0.21–318.5 kC/m{sup 2}. Volume changes induced by electron bombarding were monitored by means of Atomic Force Microscopy. Incubation doses, related to mobility of alkali ions, were measured. Low doses showed compaction of all glasses while higher doses revealed volume inflation, except for borosilicate float glass. Both surfaces of float glass were irradiated and significant differences between them were found.

  14. Volume changes in glass induced by an electron beam

    Science.gov (United States)

    Gavenda, Tadeáš; Gedeon, Ondrej; Jurek, Karel

    2014-03-01

    Three glasses (float, borosilicate float and Schott D263 glasses) were irradiated by 50 keV electron beams with doses within the range of 0.21-318.5 kC/m2. Volume changes induced by electron bombarding were monitored by means of Atomic Force Microscopy. Incubation doses, related to mobility of alkali ions, were measured. Low doses showed compaction of all glasses while higher doses revealed volume inflation, except for borosilicate float glass. Both surfaces of float glass were irradiated and significant differences between them were found.

  15. Correlation between ion induced defects and luminescence properties of K{sub 3}Na(SO{sub 4}){sub 2}: Eu nanophosphor

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, A., E-mail: anjani_physics@yahoo.co [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Sharma, S.K. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Lochab, S.P.; Kanjilal, D. [Inter University Accelerator Center, New Delhi 110 067 (India)

    2011-05-15

    The K{sub 3}Na(SO{sub 4}){sub 2}: Eu phosphor has been prepared by chemical co-precipitation method. X-ray diffraction studies show that K{sub 3}Na(SO{sub 4}){sub 2}: Eu phosphor exhibits hexagonal structure with average particle size of 42 nm. The samples were irradiated with 1.2 MeV Argon ions, with fluences varying between 10{sup 11} and 10{sup 15} ions/cm{sup 2}. Monte Carlo SRIM-2008 Simulation was used for evaluating ion range, ion energy loss and ion induced atomic displacements. Ions having a range of 2.09 {mu}m lose their energy mainly via electronic stopping, by creating large number of defects and activating different trap centers. This results in composite thermoluminescence (TL) glow curves. The growth of lower temperature peak at around 449 K which was linear in the whole studied dose range, might be attributed to the change in trap centers and luminescence centers populations. The observed variation in TL intensity of the higher temperature peak at 533 K is the resultant effect of both increases in density of ion beam tracks and high ionization density. A photoluminescence (PL) emission peak is seen around 415 nm when excited by 310 nm light, due to transition from an excited state of 4f{sup 6}5d configuration to {sup 8}S{sub 7/2} state of Eu{sup 2+} ion. The higher concentration of defects that generate nonradiative states within the band gap is responsible for decrease in PL intensity after irradiation. The composite TL glow peaks were first deconvoluted with GlowFit program and then kinetics parameters of isolated prominent peaks were calculated by the thermoluminescence peak shape and various heating rate methods.

  16. Electron-Beam Induced Transformations of Layered Tin Dichalcogenides.

    Science.gov (United States)

    Sutter, E; Huang, Y; Komsa, H-P; Ghorbani-Asl, M; Krasheninnikov, A V; Sutter, P

    2016-07-13

    By combining high-resolution transmission electron microscopy and associated analytical methods with first-principles calculations, we study the behavior of layered tin dichalcogenides under electron beam irradiation. We demonstrate that the controllable removal of chalcogen atoms due to electron irradiation, at both room and elevated temperatures, gives rise to transformations in the atomic structure of Sn-S and Sn-Se systems so that new phases with different properties can be induced. In particular, rhombohedral layered SnS2 and SnSe2 can be transformed via electron beam induced loss of chalcogen atoms into highly anisotropic orthorhombic layered SnS and SnSe. A striking dependence of the layer orientation of the resulting SnS-parallel to the layers of ultrathin SnS2 starting material, but slanted for transformations of thicker few-layer SnS2-is rationalized by a transformation pathway in which vacancies group into ordered S-vacancy lines, which convert via a Sn2S3 intermediate to SnS. Absence of a stable Sn2Se3 intermediate precludes this pathway for the selenides, hence SnSe2 always transforms into basal plane oriented SnSe. Our results provide microscopic insights into the transformation mechanism and show how irradiation can be used to tune the properties of layered tin chalcogenides for applications in electronics, catalysis, or energy storage.

  17. Photopolymerization-Induced Two-Beam Coupling and Light-Induced Scattering in Polymethyl Methacrylate

    Institute of Scientific and Technical Information of China (English)

    LI Wei; GAO Feng; TANG Bai-Quan; Christian Pruner; ZHANG Xin-Zheng; SHI Yan-Li; XU Jing-Jun; QIAO Hai-Jun; WU Qiang; Romano A. Rupp; LOU Ci-Bo; WANG Zhen-Hua

    2008-01-01

    @@ Light amplification due to two-beam coupling is realized in doped polymethyl methacrylate (PMMA) glasses. A coupling gain as large as 14 cm-1 is obtained. The dynamic behaviour of absorption and light-induced scattering due to the process of photopolymerization are also studied. The results show that the amplification and its dynamic process enable possible applications of PMMA in optical devices.

  18. Beam-induced backgrounds in detectors at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, Adrian

    2008-11-15

    There is general consensus in the high-energy physics community that the next particle collider to be built should be a linear electron-positron accelerator. Such a machine, colliding point-like particles with a well-defined initial state, would be an ideal complement to the Large Hadron Collider (LHC) and would allow high-precision measurements of the new physics phenomena that are likely to be discovered at the TeV energy scale. The most advanced project in that context is the International Linear Collider (ILC), aiming for a centre-of-mass energy of 500 GeV and a luminosity of 2 x 10{sup 34} cm{sup -2}s{sup -1} in its first stage. One of the detector concepts that are currently being developed and studied is the so-called International Large Detector (ILD). A prime feature of the ILD concept is the usage of a Time Projection Chamber (TPC) as the main tracker, which allows to reach the required momentum resolution, but which also has excellent particle identification capabilities and a highly robust and efficient tracking. The beam-beam interaction of the strongly focused particle bunches at the ILC will produce beamstrahlung photons, which can in turn scatter to electron-positron pairs. These pairs are a major source of detector backgrounds. This thesis explains the methods to study the effects of beam-induced electron-positron pair backgrounds with Mokka, a full detector simulation for the ILC that is based on Geant4, and it presents the simulation results for different detector configurations and various small modifications. The main focus of the simulations and their analysis is on the vertex detector and the TPC, but results for the inner silicon trackers and the hadronic calorimeters are shown as well. (orig.)

  19. Luminescent Poly(vinyl alcohol)/Carbon Quantum Dots Composites with Tunable Water-Induced Shape Memory Behavior in Different pH and Temperature Environments.

    Science.gov (United States)

    Yang, Guanghui; Wan, Xuejuan; Liu, Yijin; Li, Rui; Su, Yikun; Zeng, Xierong; Tang, Jiaoning

    2016-12-21

    Luminescent water-induced shape memory polymer (SMP) composites with tunable shape recovery rate are developed by blending poly(vinyl alcohol) (PVA) and carbon quantum dots (CQDs). The oxygen and active hydrogen-rich CQDs can serve as extra physical cross-linking points in PVA via strong hydrogen bonding interaction, which largely improves the shape memory performances of PVA. At room temperature, water can successfully actuate the shape recovery of deformed PVA/CQDs composite. It is demonstrated that this water-induced shape recovery is mainly attributed to the plasticizing effect of water and its competitive hydrogen bonding. Furthermore, a quantitative bending test suggests that the shape recovery time of this water-induced SMP is tunable by altering the environmental pH value and temperature, and a relatively large shape recovery time window (from 20 to 200 s) can be achieved. In addition, the introduction of CQDs endows the PVA/CQDs SMP composites with excellent luminescent property, which makes the shape change of SMP visible under UV light. It should be noted that the mild stimulus condition and tunable shape recovery performances make the luminescent visible PVA/CQDs SMP feasible for diverse biological applications in smart medical devices, stimuli-responsive drug-release, and intelligent sensors in vivo and in vitro.

  20. Energy transfer induced improvement of luminescent efficiency and thermal stability in phosphate phosphor.

    Science.gov (United States)

    Zhao, Yun; Lin, Chun Che; Wei, Yi; Chan, Ting-Shan; Li, Guogang

    2016-02-22

    Ce3+ and Eu2+/Tb3+/Mn2+ ions codoped Ca6BaP4O17 (CBPO) phosphors have been prepared via a high-temperature solid state reaction. The structural refinement indicates that the as-prepared phosphors crystallize in monoclinic phase (C2/m) and there are two Ca sites and one Ba site in host lattice. The doping ions are determined to occupy Ca sites and the emission of Ce3+ and Eu2+ ions at different Ca sites were identified and discussed. Since bright blue and yellow emissions were observed from Ce3+and Eu2+ ions monodoped CBPO under n-UV excitation, respectively. They were codoped into the CBPO for designing energy transfer from Ce3+ to Eu2+ to improve the luminescence efficiency of Eu2+. In addition, Tb3+ ions were added into the CBPO:Ce3+ system for realizing highly efficient green emission. The energy transfer mechanisms from Ce3+ to Eu2+/Tb3+ ions were discussed. Interestingly, the incorporation of Mn2+ ions into the CBPO:Ce3+ system enhanced the blue emission of Ce3+ ions due to the modification of crystal lattice. Finally, the thermal stability of CBPO:Ce3+, Eu2+/Tb3+/Mn2+ phosphors were investigated systematically and corresponding mechanisms were proposed. Based on these results, the as-prepared CBPO:Ce3+, Eu2+/Tb3+/Mn2+ phosphors can act as potential blue, yellow, green, and emission-tunable phosphors for n-UV based white LEDs.

  1. X-ray induced luminescence properties of (Y,Eu)AlO3 single crystals

    Science.gov (United States)

    Kuro, Tomoaki; Nakauchi, Daisuke; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

    2017-02-01

    We investigated photoluminescence, scintillation and dosimeter properties of (Y1-x Eux)AlO3 (x = 0.001, 0.5 and 1) single crystals (hereafter denoted as Eu:YAP for x = 0.001, EYAP for x = 0.5 and EAP for x = 1). The samples were prepared by the Floating Zone method. In photoluminescence (PL), we observed a broad emission around 300-400 nm due to host under excitation of 280 nm, and emissions due to the 4f state transitions of Eu3+ appeared around 590 nm and 615 nm. Scintillation spectra also show emission peaks around 590 and 615 nm due to the 4f state transitions of Eu3+ in all the samples. In addition, emissions around 300-400 nm due to YAP host and around 550-700 nm due to 5d-4f transitions of Eu2+ appeared in Eu:YAP. The PL and scintillation decay time profiles consisted of several exponential decay components. The fast (ns) component group was possibly due to host emission, and especially Eu:YAP demonstrated a very fast PL decay time of 16 ns. The intermediate (μs) component group was due to the 5d-4f transitions of Eu2+. The slow (ms) component group was ascribed to the 4f state transitions of Eu3+ ion. The Eu:YAP sample showed intense thermally-stimulated luminescence (TSL) with peaks at 46, 155, 255 and 443 °C. The intensity was much higher than those of EAP and EYAP. In particular, the peak at 254 °C, which showed the highest intensity, was due to doping with Eu. The TSL dose response function showed a good linearity (R2 > 0.99) over a wide dose range from 0.1 mGy to 100 mGy for Eu:YAP, which showed the highest sensitivity among the present samples.

  2. Fundamental edge broadening effects during focused electron beam induced nanosynthesis

    Directory of Open Access Journals (Sweden)

    Roland Schmied

    2015-02-01

    Full Text Available The present study explores lateral broadening effects of 3D structures fabricated through focused electron beam induced deposition using MeCpPt(IVMe3 precursor. In particular, the scaling behavior of proximity effects as a function of the primary electron energy and the deposit height is investigated through experiments and validated through simulations. Correlated Kelvin force microscopy and conductive atomic force microscopy measurements identified conductive and non-conductive proximity regions. It was determined that the highest primary electron energies enable the highest edge sharpness while lower energies contain a complex convolution of broadening effects. Moreover, it is demonstrated that intermediate energies lead to even more complex proximity effects that significantly reduce lateral edge sharpness and thus should be avoided if desiring high lateral resolution.

  3. A laser beam quality definition based on induced temperature rise.

    Science.gov (United States)

    Miller, Harold C

    2012-12-17

    Laser beam quality metrics like M(2) can be used to describe the spot sizes and propagation behavior of a wide variety of non-ideal laser beams. However, for beams that have been diffracted by limiting apertures in the near-field, or those with unusual near-field profiles, the conventional metrics can lead to an inconsistent or incomplete description of far-field performance. This paper motivates an alternative laser beam quality definition that can be used with any beam. The approach uses a consideration of the intrinsic ability of a laser beam profile to heat a material. Comparisons are made with conventional beam quality metrics. An analysis on an asymmetric Gaussian beam is used to establish a connection with the invariant beam propagation ratio.

  4. Measurements of the luminosity and normalised beam-induced background using the CMS Fast Beam Condition Monitor

    CERN Document Server

    Odell, Nathaniel Jay

    2012-01-01

    The CMS Beam Conditions and Radiation Monitoring system (BRM) is installed to protect the CMS detector from high beam losses and to provide feedback to the LHC and CMS on the beam conditions. The Fast Beam Condition Monitor (BCM1F), one of the sub-detectors in the BRM system, is installed inside the pixel volume close to the beam pipe and consists of two planes of 4 modules each located 1.8 m away from the IP, on both ends. It uses single-crystal CVD diamond sensors, radiation hard front-end electronics and an optical transmission of the signal. It is designed for single particle rate measurements, detecting both machine induced beam background and collision products on a bunch-by-bunch basis. Presented is the implementation of the normalized online beam-induced background measurement and the online instantaneous luminosity measurement. The method for determining the luminosity from the measured rates, including the absolute calibration using the Van der Meer scan, and the measurement performance will be d...

  5. Measurement and Optimization of Metal-Nanoparticle-Induced Luminescence Enhancement Factors in a Crossed-Optical Fiber Configuration

    Directory of Open Access Journals (Sweden)

    Maria Veronica Rigo

    2010-01-01

    Full Text Available A crossed-optical-fiber configuration comprised of silver nanoparticles covalently attached to the core of an optical fiber and labeled with luminescent ruthenium molecules is reported. A second optical fiber was placed at right angle of the fiber containing the nanoparticle/ruthenium, to form a fiber-fiber junction, and it was used to detect the luminescence from the ruthenium molecules bound to the first fiber. To employ the effect of metal-enhanced luminescence, the ruthenium complex was kept at an appropriate distance from the nanoparticles by polyelectrolyte spacer layers. For silver nanospheres, nanotriangles and nanorods and for spacer-layer thicknesses from 2–14 nm luminescence-enhancement factors were determined. A 27-fold luminescence enhancement was found when the ruthenium complex was placed 4 nm from silver nanotriangles. Finally, a calibration curve for the oxygen dependence of luminescence intensities and lifetimes of ruthenium complex is presented suggesting that the oxygen sensing capabilities of the nanoengineered-ruthenium complex are maintained.

  6. Reactions induced by 11Be beam at Rex-Isolde

    Directory of Open Access Journals (Sweden)

    Jeppesen H.

    2011-10-01

    Full Text Available The collision induced by the three Beryllium isotopes, 9,10,11Be, on a 64Zn target were investigated at Ec.m. ≈ 1.4 the Coulomb barrier. The experiments with the radioactive 10,11Be beams were performed at the Rex-Isolde facility at CERN. In the case of 9,10Be, elastic scattering angular distributions were measured whereas, in the 11Be case, the quasielastic scattering angular distribution was obtained. A strong damping of the quasielastic cross-section was observed in the 11Be case, in the angular range around the Coulomb-nuclear interference peak. In this latter case a large total-reaction cross-section is found. Such a cross-section is more than a factor of two larger than the ones extracted in the reactions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the 11Be case could be attributed to transfer and/or break-up events.

  7. The Vibrio fischeri quorum-sensing systems ain and lux sequentially induce luminescence gene expression and are important for persistence in the squid host.

    Science.gov (United States)

    Lupp, Claudia; Urbanowski, Mark; Greenberg, E Peter; Ruby, Edward G

    2003-10-01

    Bacterial quorum sensing using acyl-homoserine lactones (acyl-HSLs) as cell-density dependent signalling molecules is important for the transcriptional regulation of many genes essential in the establishment and the maintenance of bacteria-host associations. Vibrio fischeri, the symbiotic partner of the Hawaiian bobtail squid Euprymna scolopes, possesses two distinct acyl-HSL synthase proteins, LuxI and AinS. Whereas the cell density-dependent regulation of luminescence by the LuxI-produced signal is a well-described phenomenon, and its role in light organ symbiosis has been defined, little is known about the ain system. We have investigated the impact of the V. fischeri acyl-HSL synthase AinS on both luminescence and symbiotic colonization. Through phenotypic studies of V. fischeri mutants we have found that the AinS-signal is the predominant inducer of luminescence expression in culture, whereas the impact of the LuxI-signal is apparent only at the high cell densities occurring in symbiosis. Furthermore, our studies revealed that ainS regulates activities essential for successful colonization of E. scolopes, i.e. the V. fischeri ainS mutant failed to persist in the squid light organ. Mutational inactivation of the transcriptional regulator protein LuxO in the ainS mutant partially or completely reversed all the observed phenotypes, demonstrating that the AinS-signal regulates expression of downstream genes through the inactivation of LuxO. Taken together, our results suggest that the two quorum-sensing systems in V. fischeri, ain and lux, sequentially induce the expression of luminescence genes and possibly other colonization factors.

  8. Focused electron beam induced deposition of magnetic nanostructures

    Science.gov (United States)

    de Teresa, Jose M.

    2011-03-01

    Nanopatterning strategies of magnetic materials normally rely on standard techniques such as electron-beam lithography using electron-sensitive resists. Focused electron beam induced deposition (FEBID) is currently being investigated as an alternative single-step route to produce functional magnetic nanostructures. Thus, Co-based and Fe-based precursors have been recently investigated for the growth of magnetic nanostructures by FEBID. In the present contribution, I will give an overview of the existing literature on magnetic nanostructures by FEBID and I will focus on the growth of Co nanostructures by FEBID using Co 2 (CO)8 as precursor gas. The Co content in the nanostructures can reach 95%. Magnetotransport experiments indicate that full metallic behaviour is displayed with relatively low residual resistivity and standard anisotropic magnetoresistance (0.8%). The coercive field of nanowires with changing aspect ratio has been determined in nanowires with width down to 150 nm by means of Magneto-optical Kerr Effect and the magnetization reversal has been imaged by means of Magnetic Force Microscopy, Scanning Transmission X-ray Microscopy as well as Lorentz Microscopy experiments. Nano-Hall probes have been grown with remarkable minimum detectable magnetic flux. Noticeably, it has been found that the domain-wall propagation field is lower than the domain-wall nucleation field in L-shaped nanowires, with potential applications in magnetic logic, sensing and storage. The spin polarization of these Co nanodeposits has been determined through Andreev-Reflection experiments in ferromagnetic-superconducting nanocontacts and amounts to 35%. Recent results obtained in Fe-based nanostructures by FEBID using Fe 2 (CO)9 precursor will be also presented. I acknowledge the collaboration in this field with A. Fernandez-Pacheco, R. Cordoba, L. Serrano, S. Sangiao, L.A. Rodriguez, C. Magen, E. Snoeck, L. Morellon, M.R. Ibarra.

  9. Raman and Luminescence Investigation of Rare Earth Doped Laser-Induced Crystals-in-Glass

    Science.gov (United States)

    Knorr, Brian; Stone, Adam; Jain, Himanshu; Dierolf, Volkmar

    2015-03-01

    Laser induced crystallization of glasses is a highly spatially selective process which has the potential to produce compact, integrated optics within a glass matrix. In LaBGeO5 low temperature Combined Excitation Emission Spectroscopy (CEES) revealed that erbium incorporates into both glass-ceramics and laser-induced crystals-in-glass in predominantly one type of environment (site). The energy levels of this site were quantified. The fluorescence characteristics of the erbium ions in any site in the laser-induced crystals were found to be only weakly influenced by the irradiation conditions during growth. On the other hand, a hidden parameter, potentially boron deficiency-related defects, resulted in a significant change in the incorporation behavior of the erbium ions. Scanning confocal Raman and fluorescence spectroscopy showed that the energies of the Raman modes are shifted and the erbium fluorescence intensity is inhomgeneously distributed, despite the host glass being homogeneously doped, across the cross-sections of laser-induced crystals in glass. These fluctuations within the Raman and fluorescence are spatially correlated, implying that different erbium sites form preferentially at different locations in the crystal cross-section.

  10. Numerical Simulation of the Self-Heating Effect Induced by Electron Beam Plasma in Atmosphere

    Institute of Scientific and Technical Information of China (English)

    邓永锋; 谭畅; 韩先伟; 谭永华

    2012-01-01

    For exploiting advantages of electron beam air plasma in some unusual applications, a Monte Carlo (MC) model coupled with heat transfer model is established to simulate the characteristics of electron beam air plasma by considering the self-heating effect. Based on the model, the electron beam induced temperature field and the related plasma properties are investigated. The results indicate that a nonuniform temperature field is formed in the electron beam plasma region and the average temperature is of the order of 600 K. Moreover, much larger volume pear-shaped electron beam plasma is produced in hot state rather than in cold state. The beam ranges can, with beam energies of 75 keV and 80 keV, exceed 1.0 m and 1.2 m in air at pressure of 100 torr, respectively. Finally, a well verified formula is obtained for calculating the range of high energy electron beam in atmosphere.

  11. Measurement of Tumor Dose Using Optically Stimulated Luminescence Detectors (OSLDs) and Ionization Chambers for Primary and Metastatic Lymph Node Cancers with Head and Neck: Comparison of Beam Spoiler and Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Ok [Dept. of Radiotechnology, Wonkwang Health Science University, Iksan (Korea, Republic of); Lee, Jae Seung [Dept. of Physics, Soonchunhyang University, Seoul (Korea, Republic of); Jeong, Dong Hyeok [Research center, Dongnam Inst. of Radiological and Medical Science, Busan (Korea, Republic of)

    2011-09-15

    This study conducts cross-comparison through verification of treatment planning of using beam spoiler and bolus, according to the dose variation of different tumor bed and metastatic lymph node cancers, against ionization and optically stimulated luminescence detectors(OSLDs), in head and neck radiotherapy. Verification of treatment planning examined the feasibility of inserting detectors through simulated solid dry water slabs under identical irradiated conditions from treatment planning system to measure beam spoiler and 0.5, 1 cm bolus. In addition, two detectors were cross-compared for verification of treatment planning accuracy and reliability within {+-} 2%. The study found that, given a beam spoiler thickness of 0.5 cm and beam spoiler-to-skin distance of 10 cm subjected to optimal dose distribution given for metastatic lymph node cancers, the bolus low-level skin dose was less, and the tumor bed dose reduced slightly. Additionally, two detectors were cross-compared for accuracy within {+-} 1%. Accordingly, The use of beam spoiler was determined that reduces skin side effects and can deliver an optimal dose distribution for tumor, and to apply to future clinical studies should be performed.

  12. Analysis of excitation mechanisms of Ho3+ upconversion luminescence in Ho3+:LiYbF4 (0.2 at %) crystal via photographs of its longitudinal cross sections and via spectral and kinetic characteristics

    Science.gov (United States)

    Kazakov, B. N.; Mikheev, A. V.; Goriev, O. G.; Korableva, S. L.; Semashko, V. V.

    2016-10-01

    The results of a complex analysis of the excitation mechanisms of the up conversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are presented. The spatial distribution of the upconversion luminescence intensity is studied by the photographs of longitudinal cross sections at different positions of the laser beam waist with respect to the sample. The surface power density of the pump laser diode radiation (0.755 W, λ = 933 nm) was changed by focusing the beam (similar to Z-scanning). The dependences of the longitudinal luminescence cross sections, as well as of the spectral and kinetic characteristics of Ho3+ and Yb3+ luminescence, on the position of the laser beam waist are determined. It is found that there exist two different mechanisms of the population of the energy levels of Ho3+ ions from which green and red luminescence occur, namely, cooperative sensitization of luminescence and absorption of induced photon groups (JETP Letters, 102 (5), 279 (2015)). It is shown that the contributions of these mechanisms vary both in time and over the crystal volume. All the observed spatial, spectral, and temporal specific features of the upconversion luminescence of Ho3+:LiYbF4 (0.2 at %) crystal are qualitatively explained.

  13. Efficient manganese luminescence induced by Ce3+-Mn2+ energy transfer in rare earth fluoride and phosphate nanocrystals

    Directory of Open Access Journals (Sweden)

    Ding Yun

    2011-01-01

    Full Text Available Abstract Manganese materials with attractive optical properties have been proposed for applications in such areas as photonics, light-emitting diodes, and bioimaging. In this paper, we have demonstrated multicolor Mn2+ luminescence in the visible region by controlling Ce3+-Mn2+ energy transfer in rare earth nanocrystals [NCs]. CeF3 and CePO4 NCs doped with Mn2+ have been prepared and can be well dispersed in aqueous solutions. Under ultraviolet light excitation, both the CeF3:Mn and CePO4:Mn NCs exhibit Mn2+ luminescence, yet their output colors are green and orange, respectively. By optimizing Mn2+ doping concentrations, Mn2+ luminescence quantum efficiency and Ce3+-Mn2+ energy transfer efficiency can respectively reach 14% and 60% in the CeF3:Mn NCs.

  14. Beam-induced energy deposition issues in the Very Large Hadron Collider

    CERN Document Server

    Mokhov, N V; Foster, G W

    2001-01-01

    Energy deposition issues are extremely important in the Very Large Hadron Collider (VLHC) with huge energy stored in its 20 TeV (Stage-1) and 87.5 TeV (Stage-2) beams. The status of the VLHC design on these topics, and possible solutions of the problems are discussed. Protective measures are determined based on the operational and accidental beam loss limits for the prompt radiation dose at the surface, residual radiation dose, ground water activation, accelerator components radiation damage and quench stability. The beam abort and beam collimation systems are designed to protect accelerator from accidental and operational beam losses, IP region quadrupoles from irradiation by the products of beam-beam collisions, and to reduce the accelerator-induced backgrounds in the detectors. (7 refs).

  15. Effect of boundary conditions and convection on thermally induced motion of beams subjected to internal heating

    Institute of Scientific and Technical Information of China (English)

    MALIK Pravin; KADOLI Ravikiran; GANESAN N.

    2007-01-01

    Numerical exercises are presented on the thermally induced motion of internally heated beams under various heat transfer and structural boundary conditions. The dynamic displacement and dynamic thermal moment of the beam are analyzed taking into consideration that the temperature gradient is independent as well as dependent on the beam displacement. The effect of length to thickness ratio of the beam on the thermally induced vibration is also investigated. The type of boundary conditions has its influence on the magnitude of dynamic displacement and dynamic thermal moment. A sustained thermally induced motion is observed with progress of time when the temperature gradient being evaluated is dependent on the forced convection generated due to beam motion. A finite element method (FEM) is used to solve the structural equation of motion as well as the heat transfer equation.

  16. Electron-beam-induced deposition of platinum at low landing energies

    NARCIS (Netherlands)

    Botman, A.; De Winter, D.A.M.; Mulders, J.J.L.

    2008-01-01

    Electron-beam-induced deposition of platinum from methylcyclopentadienyl-platinum-trimethyl was performed with a focused electron beam at low landing energies, down to 10 eV. The deposition growth rate is maximal at 140 eV, with the process being over ten times more efficient than at 20 kV. No signi

  17. Silicon based light emitters utilizing radiation from dislocations; electric field induced shift of the dislocation-related luminescence

    NARCIS (Netherlands)

    Arguirov, T.; Mchedlidze, T.; Kittler, M.; Reiche, M.; Wilhelm, T.; Hoang, T.; Holleman, J.; Schmitz, J.

    2009-01-01

    Dislocation rich regions can be controllably formed at a certain location inside a silicon wafer. We studied the light emission properties of such regions located in an electric field of a p–n junction under different excitation conditions. It was found that the luminescence spectra of the dislocati

  18. Ion-Induced Beam Instability in an Electron Storage Ring

    Institute of Scientific and Technical Information of China (English)

    LI Yong-Jun; JIN Yu-Ming; LI Wei-Min; LIU Zu-Ping

    2000-01-01

    In a small electron storage ring, such as the Hefei Light Source (HLS) ring, the newly generated ions, which can not escape from the beam potential and then are trapped from turn to turn, will lead to the beam instability. The ions created by the leading bunches can perturb the trailing bunches and also themselves during their subsequent passage, which will make the amplitude of beam oscillation be damped and anti-damped periodically. A computer simulation based on the strong-weak model shows a good agreement with our analytical model using the linear theory.

  19. Pulsed Helium Ion Beam Induced Deposition: A Means to High Growth Rates

    Energy Technology Data Exchange (ETDEWEB)

    Alkemade, Paul F. A. [Delft University of Technology, Delft, Netherlands; Miro, Hozanna [Delft University of Technology, Delft, Netherlands; Van Veldhoven, Emile [TNO Van Leeuwenhoek Laboratory; Maas, Diederick [TNO Van Leeuwenhoek Laboratory; Smith, Daryl [University of Tennessee, Knoxville (UTK); Rack, P. D. [University of Tennessee, Knoxville (UTK)

    2011-01-01

    The sub-nanometer beam of a helium ion microscope was used to study and optimize helium-ion beam induced deposition of PtC nanopillars with the (CH{sub 3}){sub 3}Pt(CPCH{sub 3}) precursor. The beam current, beam dwell time, precursor refresh time, and beam focus have been independently varied. Continuous beam exposure resulted in narrow but short pillars, while pulsed exposure resulted in thinner and higher ones. Furthermore, at short dwell times the deposition efficiency was very high, especially for a defocused beam. Efficiencies were measured up to 20 times the value for continuous exposure conditions. The interpretation of the experimental data was aided by a Monte Carlo simulation of the deposition. The results indicate that two regimes are operational in ion beam induced deposition (IBID). In the first one, the adsorbed precursor molecules originally present in the beam interaction region decompose. After the original precursor layer is consumed, further depletion is averted and growth continues by the supply of molecules via adsorption and surface diffusion. Depletion around the beam impact site can be distinguished from depletion on the flanges of the growing pillars. The Monte Carlo simulations for low precursor surface coverage reproduce measured growth rates, but predict considerably narrower pillars, especially at short dwell times. Both the experiments and the simulations show that the pillar width rapidly increases with increasing beam diameter. Optimal writing strategy, good beam focusing, and rapid beam positioning are needed for efficient and precise fabrication of extended and complex nanostructures by He-IBID.

  20. Analysis of kicker noise induced beam emittance growth

    Energy Technology Data Exchange (ETDEWEB)

    Zhang W.; Sandberg, J.; Ahrens, L.; Blacker, I.M.; Brennan, M.; Blaskiewicz, M.; Fischer, W.; Hahn, H.; Huang, H.; Kling, N.; Lafky, M.; Marr, G.; Mernick, K.; Mi, J.; Minty, M.; Naylor, C.; Roser, T.; Shrey, T.; van Kuik, B.; Zelenski, A.

    2012-05-20

    Over the last few years, physicists have occasionally observed the presence of noise acting on the RHIC beams leading to emittance growth at high beam energies. While the noise was sporadic in the past, it became persistent during the Run-11 setup period. An investigation diagnosed the source as originating from the RHIC dump kicker system. Once identified the issue was quickly resolved. We report in this paper the investigation result, circuit analysis, measured and simulated waveforms, solutions, and future plans.

  1. Spectrum-Induced Changes in Non-Paraxial Property of Ultrashort Pulsed Beam

    Institute of Scientific and Technical Information of China (English)

    陆大全; 胡巍; 杨振军; 郑一周

    2003-01-01

    A spatiotemporal non-paraxial correction to the paraxial solution of ultrashort pulsed beam is obtained by using the Fourier transform and the Taylor expansion. By studying the propagation of an isodiffracting pulsed Gaussian beam with different pulse shapes, we find that there are spectrum-induced changes in the non-paraxial propagation of the pulsed beam. We analyse the influence of pulse spectrum on the non-paraxial property of the ultrashort pulsed beam and explain it base on the paraxial approximation condition.

  2. Numerical simulation of inducing characteristics of high energy electron beam plasma for aerodynamics applications

    Science.gov (United States)

    Yongfeng, DENG; Jian, JIANG; Xianwei, HAN; Chang, TAN; Jianguo, WEI

    2017-04-01

    The problem of flow active control by low temperature plasma is considered to be one of the most flourishing fields of aerodynamics due to its practical advantages. Compared with other means, the electron beam plasma is a potential flow control method for large scale flow. In this paper, a computational fluid dynamics model coupled with a multi-fluid plasma model is established to investigate the aerodynamic characteristics induced by electron beam plasma. The results demonstrate that the electron beam strongly influences the flow properties, not only in the boundary layers, but also in the main flow. A weak shockwave is induced at the electron beam injection position and develops to the other side of the wind tunnel behind the beam. It brings additional energy into air, and the inducing characteristics are closely related to the beam power and increase nonlinearly with it. The injection angles also influence the flow properties to some extent. Based on this research, we demonstrate that the high energy electron beam air plasma has three attractive advantages in aerodynamic applications, i.e. the high energy density, wide action range and excellent action effect. Due to the rapid development of near space hypersonic vehicles and atmospheric fighters, by optimizing the parameters, the electron beam can be used as an alternative means in aerodynamic steering in these applications.

  3. STUDY OF THE BEAM INDUCED RADIATION IN THE CMS DETECTOR AT THE LARGE HADRON COLLIDER

    CERN Document Server

    Singh, Amandeep P; Mokhov, Nikolai; Beri, Suman Bala

    2009-01-01

    point, are most vulnerable to beam-induced radiation. We have recently carried out extensive monte carlo simulation studies using MARS program to estimate particle fluxes and radiation dose in the CMS silicon pixel and strip trackers from proton-proton collisions at $\\sqrt s $=14 TeV and from machine induced background such as beam-gas interactions and beam-halo. We will present results on radiation dose, particle fluxes and spectra from these studies and discuss implications for radiation damage and performance of the CMS silicon tracker detec...

  4. Lateral resolution in focused electron beam-induced deposition: scaling laws for pulsed and static exposure

    Energy Technology Data Exchange (ETDEWEB)

    Szkudlarek, Aleksandra [Empa, Laboratory for Mechanics of Materials and Nanostructures, Thun (Switzerland); AGH University of Science and Technology, Department of Solid State Physics, Faculty of Physics and Applied Computer Science, Krakow (Poland); Szmyt, Wojciech; Kapusta, Czeslaw [AGH University of Science and Technology, Department of Solid State Physics, Faculty of Physics and Applied Computer Science, Krakow (Poland); Utke, Ivo [Empa, Laboratory for Mechanics of Materials and Nanostructures, Thun (Switzerland)

    2014-12-15

    In this work, we review the single-adsorbate time-dependent continuum model for focused electron beam-induced deposition (FEBID). The differential equation for the adsorption rate will be expressed by dimensionless parameters describing the contributions of adsorption, desorption, dissociation, and the surface diffusion of the precursor adsorbates. The contributions are individually presented in order to elucidate their influence during variations in the electron beam exposure time. The findings are condensed into three new scaling laws for pulsed exposure FEBID (or FEB-induced etching) relating the lateral resolution of deposits or etch pits to surface diffusion and electron beam exposure dwell time for a given adsorbate depletion state. (orig.)

  5. Detecting Thermal Barrier Coating Delamination Using Visible and Near-Infrared Luminescence from Erbium-Doped Sublayers

    Science.gov (United States)

    Eldridge, J. I.; Bencic, T. J.; Martin, R. E.; Singh, J.; Wolfe, D. E.

    2007-01-01

    Nondestructive diagnostic tools are needed to monitor early stages of delamination progression in thermal barrier coatings (TBCs) because the risk of delamination induced coating failure will compromise engine performance and safety. Previous work has demonstrated that for TBCs composed of yttria-stabilized zirconia (YSZ), luminescence from a buried europium-doped sublayer can be utilized to identify the location of TBC delamination from the substantially higher luminescence intensity observed from the delaminated regions of the TBC. Luminescence measurements from buried europium-doped layers depend on sufficient transmittance of the 532 nm excitation and 606 nm emission wavelengths through the attenuating undoped YSZ overlayer to produce easily detected luminescence. In the present work, improved delamination indication is demonstrated using erbium-doped YSZ sublayers. For visible-wavelength luminescence, the erbium-doped sublayer offers the advantage of a very strong excitation peak at 517 nm that can be conveniently excited a 514 nm Ar ion laser. More importantly, the erbium-doped sublayer also produces near-infrared luminescence at 1550 nm that is effectively excited by a 980 nm laser diode. Both the 980 nm excitation and the 1550 nm emission are transmitted through the TBC with much less attenuation than visible wavelengths and therefore show great promise for delamination monitoring through thicker or more highly scattering TBCs. The application of this approach for both electron beam physical vapor deposited (EB-PVD) and plasma-sprayed TBCs is discussed.

  6. Anion/Cation(H2PO4- and Fe3+)induced dual luminescence quenching effect based on terbium solid sensor

    Institute of Scientific and Technical Information of China (English)

    TAN

    2010-01-01

    An investigation on the photophysical properties of the newly designed terbium imidazole-4,5-dicarboxylic acid complex encapsulated in the inert matrices(tetraethoxysilane,TEOS)was performed.The composite material was very stable and showed strong green emission in pure water.Interestingly,we discovered that the luminescence of hybrid material was selectively responsive to H2PO4-.1H-NMR and fluorescence spectra supported that the receptor had strong affinity to dihydrogen phosphate.Meanwhile,the luminescence was quenched by Fe3+ when adding different metal ions such as Fe3+,Pd2+,Cd2+,Co2+ and Mn2+ concomitantly.Moreover,thin film was successfully prepared by the same materials and it also exhibited selective recognition behavior to the above two ions.

  7. Turbulence-induced persistence in laser beam wandering

    CERN Document Server

    Zunino, Luciano; Funes, Gustavo; Pérez, Darío G

    2015-01-01

    We have experimentally confirmed the presence of long-memory correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. A laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing detrended fluctuation analysis. This is a very well-known and widely used methodology to unveil memory effects from time series. Results obtained from this experimental analysis allow us to confirm that both coordinates behave as highly persistent signals for strong turbulent intensities. This finding is relevant for a better comprehension and modeling of the turbulence effects in free-space optical communication systems and other applications related to propagation of optical signals in the atmosphere.

  8. RF Cavity Induced Sensitivity Limitations on Beam Loss Monitors

    Science.gov (United States)

    Kastriotou, M.; Degiovanni, A.; Sousa, F. S. Domingues; Effinger, E.; Holzer, E. B.; Quirante, J. L. Navarro; del Busto, E. N.; Tecker, F.; Viganò, W.; Welsch, C. P.; Woolley, B. J.

    Due to the secondary showers generated when a particle hits the vacuum chamber, beam losses at an accelerator may be detected via radiation detectors located near the beam line. Several sources of background can limit the sensitivity and reduce the dynamic range of a Beam Loss Monitor (BLM). This document concentrates on potential sources of background generated near high gradient RF cavities due to dark current and voltage breakdowns. An optical fibre has been installed at an experiment of the Compact Linear Collider (CLIC) Test Facility (CTF3), where a dedicated study of the performance of a loaded and unloaded CLIC accelerating structure is undergoing. An analysis of the collected data and a benchmarking simulation are presented to estimate BLM sensitivity limitations. Moreover, the feasibility for the use of BLMs optimised for the diagnostics of RF cavities is discussed.

  9. Beam Induced Hydrodynamic Tunneling in the Future Circular Collider Components

    Science.gov (United States)

    Tahir, N. A.; Burkart, F.; Schmidt, R.; Shutov, A.; Wollmann, D.; Piriz, A. R.

    2016-08-01

    A future circular collider (FCC) has been proposed as a post-Large Hadron Collider accelerator, to explore particle physics in unprecedented energy ranges. The FCC is a circular collider in a tunnel with a circumference of 80-100 km. The FCC study puts an emphasis on proton-proton high-energy and electron-positron high-intensity frontier machines. A proton-electron interaction scenario is also examined. According to the nominal FCC parameters, each of the 50 TeV proton beams will carry an amount of 8.5 GJ energy that is equivalent to the kinetic energy of an Airbus A380 (560 t) at a typical speed of 850 km /h . Safety of operation with such extremely energetic beams is an important issue, as off-nominal beam loss can cause serious damage to the accelerator and detector components with a severe impact on the accelerator environment. In order to estimate the consequences of an accident with the full beam accidently deflected into equipment, we have carried out numerical simulations of interaction of a FCC beam with a solid copper target using an energy-deposition code (fluka) and a 2D hydrodynamic code (big2) iteratively. These simulations show that, although the penetration length of a single FCC proton and its shower in solid copper is about 1.5 m, the full FCC beam will penetrate up to about 350 m into the target because of the "hydrodynamic tunneling." These simulations also show that a significant part of the target is converted into high-energy-density matter. We also discuss this interesting aspect of this study.

  10. Beam induced electron cloud resonances in dipole magnetic fields

    Science.gov (United States)

    Calvey, J. R.; Hartung, W.; Makita, J.; Venturini, M.

    2016-07-01

    The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. These measurements are supported by both analytical models and computer simulations.

  11. Piezochromic luminescence behaviors of two new benzothiazole-enamido boron difluoride complexes: intra- and inter-molecular effects induced by hydrostatic compression.

    Science.gov (United States)

    Wang, Xiaoqing; Liu, Qingsong; Yan, Hui; Liu, Zhipeng; Yao, Mingguang; Zhang, Qingfu; Gong, Shuwen; He, Weijiang

    2015-05-01

    Two new propeller-shaped benzothiazole-enamide boron difluoride complexes exhibiting piezochromic luminescence upon mechanical grinding or hydrostatic compression were prepared. The two analogues displayed the red shift in luminescence under high pressure, while compound 2 with ICT effects showed a more sensitive piezochromic response at low pressure (<1.5 GPa). The different piezochromic luminescence behaviors of these compounds were investigated.

  12. Locally Resonant Gaps of Phononic Beams Induced by Periodic Arrays of Resonant Shunts

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng-Bing; WEN Ji-Hong; WANG Gang; HAN Xiao-Yun; WEN Xi-Sen

    2011-01-01

    @@ Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams.Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit.Therefore,the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam.However,the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far.In this work,the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment.The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.%Periodic arrays of shunted piezoelectric patches are employed to control the propagation of elastic waves in phononic beams. Each piezo-patch is connected to a single resistance-inductance-capacitance shunting circuit. Therefore, the resonances of the shunting circuits will produce locally resonant gaps in the phononic beam. However, the existence of locally resonant gaps induced by resonant shunts has not been clearly proved by experiment so far. In this work, the locally resonant gap in a piezo-shunted phononic beam is investigated theoretically and verified by experiment. The results prove that resonances of shunting circuits can produce locally resonant gaps in phononic beams.

  13. Beam Induced Hydrodynamic Tunneling in the Future Circular Collider Components

    CERN Document Server

    Tahir, Naeem Ahmad; Schmidt, Rudiger; Shutov, A; Wollmann, Daniel; Piriz, A

    2016-01-01

    A future circular collider (FCC) has been proposed as a post-Large Hadron Collider accelerator, to explore particle physics in unprecedented energy ranges. The FCC is a circular collider in a tunnel with a circumference of 80–100 km. The FCC study puts an emphasis on proton-proton high-energy and electron-positron high-intensity frontier machines. A proton-electron interaction scenario is also examined. According to the nominal FCC parameters, each of the 50 TeV proton beams will carry an amount of 8.5 GJ energy that is equivalent to the kinetic energy of an Airbus A380 (560 t) at a typical speed of 850  km/h . Safety of operation with such extremely energetic beams is an important issue, as off-nominal beam loss can cause serious damage to the accelerator and detector components with a severe impact on the accelerator environment. In order to estimate the consequences of an accident with the full beam accidently deflected into equipment, we have carried out numerical simulations of interaction of a FCC...

  14. Transparency induced by two photon interference in a beam splitter

    Institute of Scientific and Technical Information of China (English)

    Wang Kai-Ge; Yang Guo-Jian

    2004-01-01

    We propose a special two-photon state which is completely transparent in a 50/50 beam splitter. This effect is caused by the destructive two-photon interference and shows the signature of photon entanglement. We find that the symmetry of the two-photon spectrum plays the key role for the properties of two-photon interference.

  15. Metal surface temperature induced by moving laser beams

    NARCIS (Netherlands)

    Römer, G.R.B.E.; Meijer, J.

    1995-01-01

    Whenever a metal is irradiated with a laser beam, electromagnetic energy is transformed into heat in a thin surface layer. The maximum surface temperature is the most important quantity which determines the processing result. Expressions for this maximum temperature are provided by the literature fo

  16. Specific chiral sensing of amino acids using induced circularly polarized luminescence of bis(diimine)dicarboxylic acid europium(III) complexes.

    Science.gov (United States)

    Okutani, Kazuhiro; Nozaki, Koichi; Iwamura, Munetaka

    2014-06-02

    The circularly polarized luminescence (CPL) from [Eu(pda)2](-) (pda = 1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(bda)2](-) (bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) in aqueous solutions containing various amino acids was investigated. The europium(III) complexes exhibited bright-red luminescence assignable to the f-f transition of the Eu(III) ion when irradiated with UV light. Although the luminescence was not circularly polarized in the solid state or in aqueous solutions, in accordance with the achiral crystal structure, the complexes exhibited detectable induced CPL (iCPL) in aqueous solutions containing chiral amino acids. In the presence of L-pyrrolidonecarboxylic acid, both [Eu(pda)2](-) and [Eu(bda)2](-) showed similar iCPL intensity (glum ∼ 0.03 for the (5)D0 → (7)F1 transition at 1 mol·dm(-3) of the amino acid). On the other hand, in the presence of L-histidine or L-arginine, [Eu(pda)2](-) exhibited intense CPL (glum ∼ 0.08 for the (5)D0 → (7)F1 transition at 0.10 mol·dm(-3) of the amino acid), whereas quite weak CPL was observed for [Eu(bda)2](-) under the same conditions (glum amino acids, [Eu(pda)2](-) was found to be a good chiral CPL probe with high sensitivity (about 10(-2) mol·dm(-3)) and high selectivity for L-histidine at pH 3 and for L-arginine at pH 7. The mechanism of iCPL was evaluated by analysis of the fine structures in the luminescence spectra and the amino acid concentration dependence of glum. For the [Eu(pda)2](-)-histidine/arginine systems, the europium(III) complexes possess coordination structures similar to that in the crystal with slight distortion to form a chiral structure due to specific interaction with two zwitterionic amino acids. This mechanism was in stark contrast to that of the europium(III) complex-pyrrolidonecarboxylic acid system in which one amino acid coordinates to the Eu(III) ion to yield an achiral coordination structure.

  17. Acetone and the precursor ligand acetylacetone : distinctly different electron beam induced decomposition?

    NARCIS (Netherlands)

    Warneke, Jonas; Van Dorp, Willem F.; Rudolf, Petra; Stano, Michal; Papp, Peter; Matejcik, Stefan; Borrmann, Tobias; Swiderek, Petra

    2015-01-01

    In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the ga

  18. Limitations and design considerations for donor-acceptor systems in luminescent solar concentrators: the effect of coupling-induced red-edge absorption

    Science.gov (United States)

    MacQueen, Rowan W.; Tayebjee, Murad J. Y.; Webb, James E. A.; Falber, Alexander; Thordarson, Pall; Schmidt, Timothy W.

    2016-06-01

    Luminescent solar concentrators (LSCs) use luminescence and waveguiding to concentrate photons within thin dielectric slabs for use in photovoltaic, lighting, and photobioreactor applications. Donor-acceptor systems of organic chromophores are widely used in LSCs to broaden the sunlight absorption range and attempt to reduce loss-inducing reabsorption by the emitting chromophore. We use raytrace simulations across a large parameter space to model the performance of LSCs containing two novel donor-acceptor trimers based on the perylene moiety. We find that under certain conditions, trimers outperform single-dye LSCs as expected. However, at higher concentrations, a slight increase in red-edge absorption by the trimers increases reabsorption and has a deleterious effect on LSC performance. This underscores the large effect that even small changes in the red edge can have, and may discourage the use of donor-acceptor schemes with high interchromophore coupling that promotes red-edge absorption. Finally, we show that for a LSC-PV pair, selecting a PV cell that is well-matched with the LSC emission spectrum has a large effect on the flux gain of the system, and that the systems studied here are well-matched to emerging PV technologies.

  19. Correlation-induced self-focusing and self-shaping effect of a partially coherent beam

    Institute of Scientific and Technical Information of China (English)

    Yahong Chen; Yangjian Cai

    2016-01-01

    A new specially correlated partially coherent beam named nonuniform multi-Gaussian correlated(NMGC) partially coherent beam is introduced. The correlation functions of such beam in x and y directions are different from each other,i.e., nonuniform correlation function in one direction and multi-Gaussian correlated Schell-model function in the other direction. The propagation properties of an NMGC partially coherent beam in free pace are demonstrated, and we find that the intensity distribution of such beam exhibits self-focusing and self-shifting effect in one direction and self-shaping effect in the other direction on propagation. The correlation-induced self-focusing and self-shaping effect will be useful in some applications, where the high power and shaped laser is required, such as material thermal processing and laser carving.

  20. Focused electron beam induced etching of titanium with XeF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Schoenaker, F J; Cordoba, R; Fernandez-Pacheco, R; Magen, C; Zuriaga-Monroy, C; Ibarra, M R [Instituto de Nanociencia de Aragon, Universidad de Zaragoza, E-50018 Zaragoza (Spain); Stephan, O [Laboratoire de Physique des Solides, CNRS UMR 8502, Universite Paris Sud XI, Batiment 510, F-91405 Orsay (France); De Teresa, J M, E-mail: deteresa@unizar.es [Departamento de Fisica de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain)

    2011-07-01

    Titanium is a relevant technological material due to its extraordinary mechanical and biocompatible properties, its nanopatterning being an increasingly important requirement in many applications. We report the successful nanopatterning of titanium by means of focused electron beam induced etching using XeF{sub 2} as a precursor gas. Etch rates up to 1.25 x 10{sup -3} {mu}m{sup 3} s{sup -1} and minimum pattern sizes of 80 nm were obtained. Different etching parameters such as beam current, beam energy, dwell time and pixel spacing are systematically investigated, the etching process being optimized by decreasing both the beam current and the beam energy. The etching mechanism is investigated by transmission electron microscopy. Potential applications in nanotechnology are discussed.

  1. Electron beam induced modification of poly(ethylene terephthalate) films

    Energy Technology Data Exchange (ETDEWEB)

    Vasiljeva, I.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation)]. E-mail: radiant@skylink.spb.ru; Mjakin, S.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation); Makarov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Krasovsky, A.N. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Varlamov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation)

    2006-10-15

    Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

  2. Chiral Sensing of Various Amino Acids Using Induced Circularly Polarized Luminescence from Europium(III) Complexes of Phenanthroline Dicarboxylic Acid Derivatives.

    Science.gov (United States)

    Uchida, Taka-Aki; Nozaki, Koichi; Iwamura, Munetaka

    2016-09-06

    Circularly polarized luminescence (CPL) was observed from [Eu(dppda)2 ](-) (dppda=4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid) and [Eu(pzpda)2 ](-) (pzpda=pyrazino[2,3-f][1,10]phenanthroline-7,10-dicarboxylic acid) in aqueous solutions containing various amino acids. The selectivity of these complexes towards amino acids enabled them to be used as chiral sensors and their behavior was compared with that of [Eu(pda)2 ](-) (pda=1,10-phenanthroline-2,9-dicarboxylic acid). As these Eu(III) complexes have achiral D2d structures under ordinary conditions, there were no CPL signals in the emission assigned to f-f transitions. However, when the solutions contained particular amino acids they exhibited detectable CPL signals with glum values of about 0.1 (glum =CPL/2 TL; TL=total luminescence). On examining 13 amino acids with these three Eu(III) complexes, it was found that whether an amino acid induced a detectable CPL depended on the Eu(III) complex ligands. For example, when ornithine was used as a chiral agent, only [Eu(dppda)2 ](-) exhibited intense CPL in aqueous solutions of 10(-2)  mol dm(-3) . Steep amino acid concentration dependence suggested that CPL in [Eu(dppda)2 ](-) and [Eu(pzpda)2 ](-) was induced by the association of four or more amino acid molecules, whereas CPL in [Eu(pda)2 ](-) was induced by association of two arginine molecules.

  3. Probe beam-free detection of terahertz wave by electroluminescence induced by intense THz pulse

    Science.gov (United States)

    Shin, J.; Jin, Z.; Nosaka, Y.; Nakazawa, T.; Kodama, R.

    2016-03-01

    Recently, a table-top fs laser system can generate MW terahertz (THz) pulse with its electric field higher than 100 kV/cm can be generated by several schemes. Such a strong THz field can directly drive electrons inside various materials. Here, we demonstrated a direct THz electric field detection method by measuring the electroluminescence induced by intense THz pulse inside commonly available light emitting diode. An intense THz wave obtained by the two-color laser scheme was focused onto LED along with an external DC bias to induce luminescence which we found proportional to the amplitude of the incident THz field. The scheme can be useful to realize a low-cost, probe-free THz detection and imaging system.

  4. Ion beam induced charge characterisation of a silicon microdosimeter using a heavy ion microprobe

    Science.gov (United States)

    Cornelius, Iwan; Siegele, Rainer; Rosenfeld, Anatoly B.; Cohen, David D.

    2002-05-01

    An ion beam induced charge (IBIC) facility has been added to the existing capabilities of the ANSTO heavy ion microprobe and the results of the first measurements are presented. Silicon on insulator (SOI) diode arrays with microscopic junction sizes have recently been proposed as microdosimeters for hadron therapy. A 20 MeV carbon beam was used to perform IBIC imaging of a 10 μm thick SOI device.

  5. Conditions for coherent-synchrotron-radiation-induced microbunching suppression in multibend beam transport or recirculation arcs

    Science.gov (United States)

    Tsai, C.-Y.; Di Mitri, S.; Douglas, D.; Li, R.; Tennant, C.

    2017-02-01

    The coherent synchrotron radiation (CSR) of a high-brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in beam phase space degradation. On one hand, CSR can perturb electron transverse motion in dispersive regions along the beam line and possibly cause emittance growth. On the other hand, the CSR effect on the longitudinal beam dynamics could result in microbunching instability. For transport arcs, several schemes have been proposed to suppress the CSR-induced emittance growth. Correspondingly, a few scenarios have been introduced to suppress CSR-induced microbunching instability, which however mostly aim for linac-based machines. In this paper we provide sufficient conditions for suppression of CSR-induced microbunching instability along transport or recirculation arcs. Examples are presented with the relevant microbunching analyses carried out by our developed semianalytical Vlasov solver [C.-Y. Tsai, D. Douglas, R. Li, and C. Tennant, Linear microbunching analysis for recirculation machines, Phys. Rev. ST Accel. Beams 19, 114401 (2016), 10.1103/PhysRevAccelBeams.19.114401]. The example lattices include low-energy (˜100 MeV ) and high-energy (˜1 GeV ) recirculation arcs, and medium-energy compressor arcs. Our studies show that lattices satisfying the proposed conditions indeed have microbunching gain suppressed. Beam current dependences of maximal CSR microbunching gains are also demonstrated, which should help outline a beam line design for different scales of nominal currents. We expect this analysis can shed light on the lattice design approach that aims to control the CSR-induced microbunching.

  6. Studies on alpha-induced astrophysical reactions using the low-energy RI beam separator CRIB

    Directory of Open Access Journals (Sweden)

    Yamaguchi H.

    2014-03-01

    Full Text Available Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator, which is a low-energy RI beam separator at Center for Nuclear Study (CNS of the University of Tokyo. Two major methods to study them are the α resonant scattering, and direct measurements of (α,p reactions using an active or inactive helium gas target. Among the recent studies at CRIB, the measurement of 7Be+α resonant scattering is discussed.

  7. The influence of radiation-induced defects on thermoluminescence and optically stimulated luminescence of α-Al2O3:C

    Science.gov (United States)

    Nyirenda, A. N.; Chithambo, M. L.

    2017-04-01

    It is known that when α-Al2O3:C is exposed to excessive amounts of ionising radiation, defects are induced within its matrix. We report the influence of radiation-induced defects on the thermoluminescence (TL) and optically stimulated luminescence (OSL) measured from α-Al2O3:C after irradiation to 1000 Gy. These radiation-induced defects are thermally unstable in the region 450-650 °C and result in TL peaks in this range when the TL is measured at 1 °C/s. Heating a sample to 700 °C obliterates the radiation-induced defects, that is, the TL peaks corresponding to the radiation induced defects are no longer observed in the subsequent TL measurements when moderate irradiation doses below 10 Gy are used. The charge traps associated with these radiation-induced defects are more stable than the dosimetric trap when the sample is exposed to either sunlight or 470-nm blue light from LEDs. TL glow curves measured following the defect-inducing irradiation produce a dosimetric peak that is broader and positioned at a higher temperature than observed in glow curves obtained before the heavy irradiation. In addition, sample sensitization/desensitization occurs due to the presence of these radiation-induced defects. Furthermore, both the activation energy and the kinetic order of the dosimetric peak evaluated when the radiation-induced defects are present in the sample are significantly lower in value than those obtained when these defects are absent. The radiation-induced defects also affect the shape and total light sum of the OSL signal as well as the position and width of the resultant residual phototransferred thermoluminescence main peak.

  8. Beam-Induced Multipactoring and Electron-Cloud Effects in Particle Accelerators

    CERN Document Server

    Caspers, Friedhelm; Scandale, Walter; Zimmermann, F

    2009-01-01

    In the beam pipe of high-energy proton or positron accelerators an “electron cloud” can be generated by a variety of processes, e.g. by residual-gas ionization, by photoemission from synchrotron radiation, and, most importantly, by secondary emission via a beam-induced multipactoring process. The electron cloud commonly leads to a degradation of the beam vacuum by several orders of magnitude, to fast beam instabilities, to beam-size increases, and to fast or slow beam losses. At the Large Hadron Collider (LHC), the cloud electrons could also give rise to an additional heat load inside cold superconducting magnets. In addition to the direct heat deposition from incoherently moving electrons, a potential “magnetron effect” has been conjectured, where electrons would radiate coherently when moving in a strong magnetic field under the simultaneous influence of a beam-induced electric “wake” field that may become resonant with the cyclotron frequency. Electron-cloud effects are already being observed w...

  9. Nano-electron beam induced current and hole charge dynamics through uncapped Ge nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, A.; El Hdiy, A.; Troyon, M. [Laboratoire de Recherche en Nanosciences, Bat. 6, case no 15, UFR Sciences, Universite de Reims Champagne Ardenne, 51687 Reims Cedex 2 (France); Amiard, G.; Ronda, A.; Berbezier, I. [IM2NP, Faculte des Sciences et Techniques, Campus de Saint Jerome - Case 142, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)

    2012-04-16

    Dynamics of hole storage in spherical Ge nanocrystals (NCs) formed by a two step dewetting/nucleation process on an oxide layer grown on an n-doped <001> silicon substrate is studied using a nano-electron beam induced current technique. Carrier generation is produced by an electron beam irradiation. The generated current is collected by an atomic force microscope--tip in contact mode at a fixed position away from the beam spot of about 0.5 {mu}m. This distance represents the effective diffusion length of holes. The time constants of holes charging are determined and the effect of the NC size is underlined.

  10. State-space approach to vibration of gold nano-beam induced by ramp type heating

    Institute of Scientific and Technical Information of China (English)

    Hamdy M Youssef; Khaled A Elsibai

    2010-01-01

    In the nanoscale beam, two effects become domineering. One is the non-Fourier effect in heat conduction and the other is the coupling effect between temperature and strain rate. In the present study, a generalized solution for the generalized thermoelastic vibration of gold nano-beam resonator induced by ramp type heating is developed. The solution takes into account the above two effects. State-space and Laplace transform methods are used to determine the lateral vibration, the temperature, the displacement, the stress and the strain energy of the beam. The effects of the relaxation time and the ramping time parameters have been studied.

  11. On compensating tune spread induced by space charge in bunched beams

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko V. N.; Wang, G.

    2014-05-09

    Space charge effects play significant role in modern-day accelerators. These effects frequently constrain attainable beam parameters in an accelerator, or, in an accelerator chain. They also could limit the luminosity of hadron colliders operating either at low energies or with a sub-TeV high brightness hadron beams. The latter is applied for strongly cooled proton and ion beams in eRHIC – the proposed future electron-ion collider at Brookhaven National Laboratory. A number of schemes for compensating space charge effects in a coasting (e.g. continuous) hadron beam were proposed and some of them had been tested. Using a proper transverse profile of the electron beam (or plasma column) for a coasting beam would compensate both the tune shift and the tune spread in the hadron beam. But all of these methods do not address the issue of tune spread compensation of a bunched hadron beam, e.g. the tune shift dependence on the longitudinal position inside the bunch. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with miss-matched longitudinal velocity to compensate the space charge induced tune-shift and tune spread. We present a number of practical examples of such system.

  12. Radiation-induced luminescence from TiO{sub 2} by 10 keV O{sup +}, N{sup +} and Ar{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Sin-iti, E-mail: kitazawa.siniti@jaea.go.j [Naka Fusion Institute, Japan Atomic Energy Agency (JAEA), 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Nuclear Science Research Institute, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Saitoh, Yuichi; Yamamoto, Shunya; Asano, Masaharu [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan); Ishiyama, Shintaro [Nuclear Science Research Institute, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan)

    2009-05-01

    Radiation-induced luminescence (RIL) produced by 10 keV O{sup +}, N{sup +} and Ar{sup +} irradiation at room temperature has been used to study energy transfer in titanium dioxide (TiO{sub 2}) targets. RIL spectra in the UV-visible region show numerous atomic lines and three bands. Two visible bands by crystalline defects and an UV band at 3.9 eV originating from radiation transitions between the Ti{sup 3+} 3d and O{sup 2-} 2 s states in the TiO{sub 2} crystal are observed. The experimental results suggest that the excitations were not mainly produced by transitions from the ground state to excited states but by cascade radiations from higher excited states.

  13. Electron beam induced THz emissions from nanotube array

    Science.gov (United States)

    Kumar, Ashok; Kumar, Pawan

    2016-10-01

    A new scheme of terahertz radiation generation by passing an ultrashort electron bunch over a planar array of nanotube/nanorod across their lengths is proposed and analyzed. The beam pulse exerts a repulsive impulse on the free electron cylinder of each nanorod and displaces them with respect to ion cylinder. After the passage of the pulse, the electron cylinders oscillate at their natural frequency ω p / √{ 2 } (where ω p is the plasma frequency of electrons in each carbon nanotube) acting as phased array dipole antennae, emitting THz radiation.

  14. Defects induced luminescence and tuning of bandgap energy narrowing in ZnO nanoparticles doped with Li ions

    KAUST Repository

    Awan, Saif Ullah

    2014-08-28

    Microstructural and optical properties of Zn1-yLiyO (0.00 ≤y ≤0.10) nanoparticles are investigated. Li incorporation leads to substantial changes in the structural characterization. From micro-structural analysis, no secondary phases or clustering of Li was detected. Elemental maps confirmed homogeneous distribution of Li in ZnO. Sharp UV peak due to the recombination of free exciton and defects based luminescence broad visible band was observed. The transition from the conduction band to Zinc vacancy defect level in photoluminescence spectra is found at 518±2.5nm. The yellow luminescence was observed and attributed to Li related defects in doped samples. With increasing Li doping, a decrease in energy bandgap was observed in the range 3.26±0.014 to 3.17±0.018eV. The bandgap narrowing behavior is explained in terms of the band tailing effect due to structural disorder, carrier-impurities, carrier-carrier, and carrier-phonon interactions. Tuning of the bandgap energy in this class of wide bandgap semiconductor is very important for room temperature spintronics applications and optical devices. © 2014 AIP Publishing LLC.

  15. Robust population transfer in atomic beams induced by Doppler shifts

    Science.gov (United States)

    Unanyan, R. G.

    2016-10-01

    The influence of photon momentum recoil on adiabatic population transfer in an atomic three-level lambda system is studied. It is shown that the Doppler frequency shifts, due to atomic motion, can play an important role in adiabatic population transfer processes of atomic internal states by a pair of laser fields. For the limiting case of slow atoms (Doppler shift much smaller than the photon recoil energy), the atoms occupy the same target state regardless of the order of switching of laser fields, while for the case of fast atoms interacting with the intuitive sequence of pulses, the target state is the intermediate atomic state. Furthermore, it is shown that this novel technique for adiabatic population transfer is related to a level crossing in the bright-intermediate state basis (rather than in the original atomic basis). It is shown that these processes are robust with respect to parameter fluctuations, such as the laser pulse area and the relative spatial offset (delay) of the laser beams. The obtained results can be used for the control of temporal evolution of atomic populations in cold atomic beams by externally adjustable Doppler shifts.

  16. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  17. Quantum Interference of Multiple Beams Induced by Multiple Scattering

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter

    2011-01-01

    We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging.......We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging....

  18. A luminescent nisin biosensor

    Science.gov (United States)

    Immonen, Nina; Karp, Matti

    2006-02-01

    Nisin is a lantibiotic, an antibacterial peptide produced by certain Lactococcus lactis strains that kills or inhibits the growth of other bacteria. Nisin is widely used as a food preservative, and its long-time use suggests that it can be generally regarded as safe. We have developed a method for determining the amount of nisin in food samples that is based on luminescent biosensor bacteria. Bacterial luciferase operon luxABCDE was inserted into plasmid pNZ8048, and the construct was transformed by electroporation into Lc. lactis strain NZ9800, whose ability to produce nisin has been erased by deletion of the gene nisA. The operon luxABCDE has been modified to be functional in gram-positive bacteria to confer a bioluminescent phenotype without the requirement of adding an exogenous substrate. In the plasmid pNZ8048, the operon was placed under control of the nisin-inducible nisA promoter. The chromosomal nisRK genes of Lc. lactis NZ9800 allow it to sense nisin in the environment and relay this signal via signal transduction proteins NisK and NisR to initiate transcription from nisA promoter. In the case of our sensor bacteria, this leads to production of luciferase and, thus, luminescence that can be directly measured from living bacteria. Luminescence can be detected as early as within minutes of induction. The nisin assay described here provides a detection limit in the sub-picogram level per ml, and a linear area between 1 - 1000 pg/ml. The sensitivity of this assay exceeds the performance of all previously published methods.

  19. Using Si-doped diamond plate of sandwich type for spatial profiling of laser beam

    Science.gov (United States)

    Shershulin, V. A.; Samoylenko, S. R.; Sedov, V. S.; Kudryavtsev, O. S.; Ralchenko, V. G.; Nozhkina, A. V.; Vlasov, I. I.; Konov, V. I.

    2017-02-01

    We demonstrated a laser beam profiling method based on imaging of the laser induced photoluminescence of a transparent single-crystal diamond plate. The luminescence at 738 nm is caused by silicon-vacancy color centers formed in the epitaxial diamond film by its doping with Si during CVD growth of the film. The on-line beam monitor was tested for a cw laser emitting at 660 nm wavelength.

  20. Low level RF systems for synchrotrons part II: High Intensity. Compensation of the beam induced effects

    CERN Document Server

    Baudrenghien, P

    2005-01-01

    The high intensity regime is reached when the voltage induced by the beam in the RF cavities is of an amplitude comparable to the desired accelerating voltage. In steady state this beam loading can be compensated by providing extra RF power. Transient beam loading occurs at injection or in the presence of a beam intensity that is not uniform around the ring. The transients are periodic at the revolution frequency. Without correction transient beam loading can be very harmful: The stable phase and bucket area will not be equal for all bunches. Strong beam loading often goes in pair with longitudinal instabilities because the RF cavities are a large contributor to the total ring impedance. The low level systems that reduce the effect of the transient beam loading will also increase the threshold intensity of the longitudinal instability caused by the cavity impedance at the fundamental RF frequency. Four classic methods are presented here: Feedforward, RF feedback, long delay feedback and bunch by bunch feedbac...

  1. Electron Beam Induced Artifacts During in situ TEM Deformation of Nanostructured Metals

    Science.gov (United States)

    Sarkar, Rohit; Rentenberger, Christian; Rajagopalan, Jagannathan

    2015-11-01

    A critical assumption underlying in situ transmission electron microscopy studies is that the electron beam (e-beam) exposure does not fundamentally alter the intrinsic deformation behavior of the materials being probed. Here, we show that e-beam exposure causes increased dislocation activation and marked stress relaxation in aluminum and gold films spanning a range of thicknesses (80-400 nanometers) and grain sizes (50-220 nanometers). Furthermore, the e-beam induces anomalous sample necking, which unusually depends more on the e-beam diameter than intensity. Notably, the stress relaxation in both aluminum and gold occurs at beam energies well below their damage thresholds. More remarkably, the stress relaxation and/or sample necking is significantly more pronounced at lower accelerating voltages (120 kV versus 200 kV) in both the metals. These observations in aluminum and gold, two metals with highly dissimilar atomic weights and properties, indicate that e-beam exposure can cause anomalous behavior in a broad spectrum of nanostructured materials, and simultaneously suggest a strategy to minimize such artifacts.

  2. On Compensating Tune Spread Induced by Space Charge in Bunched Beams

    CERN Document Server

    Litvinenko, Vladimir N

    2014-01-01

    Space charge effects play significant role in modern-day accelerators. These effects frequently constrain attainable beam parameters in an accelerator - or - in an accelerator chain. They also could limit the luminosity of hadron colliders operating either at low energies or with a sub-TeV high brightness hadron beams. A number of schemes for compensating space charge effects in a coasting (e.g. continuous) hadron beam were proposed and some of them had been tested. But all of these methods do not address the issue of tune spread compensation of a bunched hadron beam, e.g. the tune shift dependence on the longitudinal position inside the bunch. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with miss-matched longitudinal velocity to compensate the space charge induced tune-shift and tune spread. We present a number of practical examples of such system.

  3. Experiments on the margin of beam induced quenches a superconducting quadrupole magnet in the LHC

    CERN Document Server

    Bracco, C; Bednarek, M J; Nebot Del Busto, E; Goddard, B; Holzer, E B; Nordt, A; Sapinski, M; Schmidt, R; Solfaroli Camillocci, M; Zerlauth, M

    2012-01-01

    Protection of LHC equipment relies on a complex system of collimators to capture injected and circulating beam in case of LHC kicker magnet failures. However, for specific failures of the injection kickers, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and cannot be excluded during future operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet currents. The results of the experiments are presented.

  4. Field-induced single-ion magnetic behaviour in a highly luminescent Er{sup 3+} complex

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, J.T. [Solid State Group, UCQR, IST/CTN, Instituto Superior Técnico, UTL, Estrada Nacional 10, km 139.7, 2695-066 Bobadela LRS (Portugal); Pereira, L.C.J., E-mail: lpereira@ctn.ist.utl.pt [Solid State Group, UCQR, IST/CTN, Instituto Superior Técnico, UTL, Estrada Nacional 10, km 139.7, 2695-066 Bobadela LRS (Portugal); Martín-Ramos, P. [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, P-3004-516 Coimbra (Portugal); Higher Polytechnic School of Huesca, University of Zaragoza, Carretera Cuarte, s/n, 22071 Huesca (Spain); Ramos Silva, M. [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, P-3004-516 Coimbra (Portugal); Zheng, Y.X.; Liang, X. [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Ye, H.Q. [Materials Research Institute and School of Physics and Astronomy Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Peng, Y. [Materials Research Institute and School of Biological and Chemical, Sciences, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Baker, P.J. [Materials Research Institute and School of Physics and Astronomy Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Wyatt, P.B. [Materials Research Institute and School of Biological and Chemical, Sciences, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Gillin, W.P. [Materials Research Institute and School of Physics and Astronomy Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

    2015-06-15

    The magnetic properties of a perfluorinated Er{sup 3+} complex, with record luminescent properties, have been investigated. [Er(F-TPIP){sub 3}] displays thermally activated slow relaxation of the magnetisation under an applied H{sub DC} field of 500 Oe. The effective relaxation barrier E{sub eff} is found to be 26.8 K (18.6 cm{sup −1}). At zero static field, efficient quantum tunnelling of the magnetization occurs. - Highlights: • Under DC field, slow relaxation of magnetisation occurs with a barrier of 27 K. • Efficient quantum tunnelling of magnetization is displayed at zero static field. • The lifetime value of the {sup 4}I{sub 13/2} multiplet is τ = 0.28 ms. • [Er(F-TPIP){sub 3}] complex can be considered a multifunctional material.

  5. Plasmon-enhanced optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  6. Focused helium and neon ion beam induced etching for advanced extreme ultraviolet lithography mask repair

    NARCIS (Netherlands)

    Gonzalez, Carlos M.; Timilsina, Rajendra; Li, Guoliang; Duscher, Gerd; Rack, Philip D.; Slingenbergh, Winand; van Dorp, Willem F.; De Hosson, Jeff T. M.; Klein, Kate L.; Wu, Huimeng M.; Stern, Lewis A.

    2014-01-01

    The gas field ion microscope was used to investigate helium and neon ion beam induced etching of nickel as a candidate technique for extreme ultraviolet (EUV) lithography mask editing. No discernable nickel etching was observed for room temperature helium exposures at 16 and 30 keV in the dose range

  7. Electron beam induced electronic transport in alkyl amine-intercalated VOx nanotubes

    NARCIS (Netherlands)

    O'Dwyer, C.; Lavayen, V.; Clavijo-Cedeno, C.; Sotomayor Torres, C.M.

    2008-01-01

    The electron beam induced electronic transport in primary alkyl amine-intercalated V2O5 nanotubes is investigated where the organic amine molecules are employed as molecular conductive wires to an aminosilanized substrate surface and contacted to Au interdigitated electrode contacts. The results dem

  8. Three-dimensional Nanostructures Fabricated by Ion-Beam-Induced Deposition

    NARCIS (Netherlands)

    Chen, P.

    2010-01-01

    The direct writing technology known as ion-beam-induced deposition (IBID) has been attracting attention mainly because of its high degree of flexibility of locally prototyping three-dimensional (3D) nanostructures. These high-resolution nanostructures have various research applications. However, no

  9. Investigation of morphological changes in platinum-containing nanostructures created by electron-beam-induced deposition

    NARCIS (Netherlands)

    Botman, A.; Hesselberth, M.; Mulders, J.J.L.

    2008-01-01

    Focused electron-beam-induced deposition (EBID) allows the rapid fabrication of three-dimensional nanodevices and metallic wiring of nanostructures, and is a promising technique for many applications in nanoresearch. The authors present two topics on platinum-containing nanostructures created by EBI

  10. Creating pure nanostructures from electron-beam-induced deposition using purification techniques: a technology perspective

    NARCIS (Netherlands)

    Botman, A.; Mulders, J.J.L.; Hagen, C.W.

    2009-01-01

    The creation of functional nanostructures by electron-beam-induced deposition (EBID) is becoming more widespread. The benefits of the technology include fast ‘point-and-shoot’ creation of three-dimensional nanostructures at predefined locations directly within a scanning electron microscope. One sig

  11. Charging effects during focused electron beam induced deposition of silicon oxide

    NARCIS (Netherlands)

    de Boer, Sanne K.; van Dorp, Willem F.; De Hosson, Jeff Th. M.

    2011-01-01

    This paper concentrates on focused electron beam induced deposition of silicon oxide. Silicon oxide pillars are written using 2, 4, 6, 8, 10-pentamethyl-cyclopenta-siloxane (PMCPS) as precursor. It is observed that branching of the pillar occurs above a minimum pillar height. The branching is attrib

  12. The role of electron-stimulated desorption in focused electron beam induced deposition

    NARCIS (Netherlands)

    van Dorp, Willem F.; Hansen, Thomas W.; Wagner, Jakob B.; De Hosson, Jeff T. M.

    2013-01-01

    We present the results of our study about the deposition rate of focused electron beam induced processing (FEBIP) as a function of the substrate temperature with the substrate being an electron-transparent amorphous carbon membrane. When W(CO)(6) is used as a precursor it is observed that the growth

  13. Roles of secondary electrons and sputtered atoms in ion-beam-induced deposition

    NARCIS (Netherlands)

    Chen, P.; Salemink, H.W.M.; Alkemade, P.F.A.

    2009-01-01

    The authors report the results of investigating two models for ion-beam-induced deposition (IBID). These models describe IBID in terms of the impact of secondary electrons and of sputtered atoms, respectively. The yields of deposition, sputtering, and secondary electron emission, as well as the ener

  14. Electron beam induced oxidation of Ni3Al surfaces : electron flux effects

    NARCIS (Netherlands)

    Koch, S.A.; Palasantzas, G.; Agterveld, D.T.L. van; Hosson, J.Th.M. De

    2002-01-01

    Electron beam irradiation of polycrystalline boron doped Ni3Al (at 300 K and under ultrahigh vacuum conditions) induces fast oxidation. The rate and depth of oxidation initially increase with increasing electron flux as indicated by results from Auger electron spectroscopy. Curves of oxygen developm

  15. Ultrahigh resolution focused electron beam induced processing : the effect of substrate thickness

    NARCIS (Netherlands)

    van Dorp, W. F.; Lazic, I.; Beyer, A.; Goelzhaeuser, A.; Wagner, J. B.; Hansen, T. W.; Hagen, C. W.

    2011-01-01

    It is often suggested that the growth in focused electron beam induced processing (FEBIP) is caused not only by primary electrons, but also (and even predominantly) by secondary electrons (SEs). If that is true, the growth rate for FEBIP can be changed by modifying the SE yield. Results from our Mon

  16. Beam deflection induced by E×B near a linear filament cathode

    Science.gov (United States)

    Zhang, Huashun; Jiang, Jiasheng

    2017-02-01

    Beam deflection induced by E×B near a linear filament cathode in a two grid electron gun is presented theoretically and experimentally. The experimental results are consistent with the calculation based on the theoretical equations. The influences upon performance and design of electron gun with linear filament cathode, which is used broadly in electrocurtain accelerators, are discussed in detail.

  17. Photon Luminescence of the Moon

    Science.gov (United States)

    Wilson, T.L.; Lee, K.T.

    2009-01-01

    Luminescence is typically described as light emitted by objects at low temperatures, induced by chemical reactions, electrical energy, atomic interactions, or acoustical and mechanical stress. An example is photoluminescence created when photons (electromagnetic radiation) strike a substance and are absorbed, resulting in the emission of a resonant fluorescent or phosphorescent albedo. In planetary science, there exists X-ray fluorescence induced by sunlight absorbed by a regolith a property used to measure some of the chemical composition of the Moon s surface during the Apollo program. However, there exists an equally important phenomenon in planetary science which will be designated here as photon luminescence. It is not conventional photoluminescence because the incoming radiation that strikes the planetary surface is not photons but rather cosmic rays (CRs). Nevertheless, the result is the same: the generation of a photon albedo. In particular, Galactic CRs (GCRs) and solar energetic particles (SEPs) both induce a photon albedo that radiates from the surface of the Moon. Other particle albedos are generated as well, most of which are hazardous (e.g. neutrons). The photon luminescence or albedo of the lunar surface induced by GCRs and SEPs will be derived here, demonstrating that the Moon literally glows in the dark (when there is no sunlight or Earthshine). This extends earlier work on the same subject [1-4]. A side-by-side comparison of these two albedos and related mitigation measures will also be discussed.

  18. Ion-beam induced atomic mixing in isotopically controlled silicon multilayers

    Science.gov (United States)

    Radek, M.; Bracht, H.; Liedke, B.; Böttger, R.; Posselt, M.

    2016-11-01

    Implantation of germanium (Ge), gallium (Ga), and arsenic (As) into crystalline and preamorphized isotopically controlled silicon (Si) multilayer structures at temperatures between 153 K and 973 K was performed to study the mechanisms mediating ion-beam induced atomic mixing. Secondary-ion-mass-spectrometry was applied to determine concentration-depth profiles of the stable isotopes before and after ion implantation. The intermixing is analytically described by a depth-dependent displacement function. The maximum displacement is found to depend not only on temperature and microstructure but also on the doping type of the implanted ion. Molecular dynamics calculations evaluate the contribution of cascade mixing, i.e., thermal-spike mixing, to the overall observed atomic mixing. Calculated and experimental results on the temperature dependence of ion-beam mixing in the amorphous and crystalline structures provide strong evidence for ion-beam induced enhanced crystallization and enhanced self-diffusion, respectively. On the other hand, the former process is confirmed by channeling Rutherford backscattering analyses of the amorphous layer thickness remaining after implantation, the latter process is consistently attributed to the formation of highly mobile Si di-interstitials formed under irradiation and in the course of damage annealing. The observed ion-beam mixing in Si is compared to recent results on ion-beam mixing of Ge isotope multilayers that, in contrast to Si, are fully described by thermal-spike mixing only.

  19. Evaluation of source term induced by beam loss in the superconducting linear accelerator at RAON

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Jin; Kim, Su Na; Nam, Shin Woo; Chung, Yon Sei [Rare Isotope Science Project, Institute for Basic Science, Daejeon (Korea, Republic of)

    2014-11-15

    As a new world-class heavy ion accelerator, RAON is able to accelerate heavy ions from proton to uranium with the energy up to -400 MeV/u and produce rare isotopes. These high purity, high intensity, and high energy beams generate the various secondary radiation which will impact on the shielding aspects of the main linear accelerator tunnels. In the main tunnel the secondary neutrons are produced by uniform beam-loss or accident criteria. In this paper evaluations of several source terms induced by beam-loss will be discussed along with the physics model of the Monte Carlo simulation codes. The beam-loss criteria were tested for the evaluation of source term for the main beam line tunnel of the RAON accelerator. It was found that the amount of the secondary neutrons depends on the incident angle of projectile on the beam pipe and the mass and energy of projectile. The influence of selected physics models and libraries of MCNPX and PHITS has been examined. The secondary neutrons were produced most in the CEM and LAQGSM model.

  20. Ion beam induced optical and surface modification in plasmonic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Udai B., E-mail: udaibhansingh123@gmail.com; Gautam, Subodh K.; Kumar, Sunil; Hooda, Sonu; Ojha, Sunil; Singh, Fouran

    2016-07-15

    In present work, ion irradiation induced nanostructuring has been exploited as an efficient and effective tool for synthesis of coupled plasmonics nanostructures by using 1.2 MeV Xe ions on Au/ZnO/Au system deposited on glass substrate. The results are correlated on the basis of their optical absorption, surface morphologies and enhanced sensitivity of evolved phonon modes by using UV Visible spectroscopy, scanning electron microscopy (SEM), and Raman spectroscopy (RS), respectively. Optical absorbance spectra of plasmonic nanostructures (NSs) show a decrease in band gap, which may be ascribed to the formation of defects with ion irradiation. The surface morphology reveals the formation of percolated NSs upon ion irradiation and Rutherford backscattering spectrometry (RBS) study clearly shows the formation of multilayer system. Furthermore, RS measurements on samples are studied to understand the enhanced sensitivity of ion irradiation induced phonon mode at 573 cm{sup −1} along with other modes. As compared to pristine sample, a stronger and pronounced evolution of these phonon modes is observed with further ion irradiation, which indicates localized surface plasmon results with enhanced intensity of phonon modes of Zinc oxide (ZnO) material. Thus, such plasmonic NSs can be used as surface enhanced Raman scattering (SERS) substrates.

  1. Vibration induced sliding: theory and experiment for a beam with a spring-loaded mass

    DEFF Research Database (Denmark)

    Miranda, Erik; Thomsen, Jon Juel

    1998-01-01

    The study sets up a simple model for predicting vibration induced sliding of mass, and provides quantitative experimental evidence for the validity of the model. The results lend confidence to recent theoretical developments on using vibration induced sliding for passive vibration damping......, and contributes to a further understanding of this nonlinear phenomenon. A mathematical model is set up to describe vibration induced sliding for a base-excited cantilever beam with a spring-loaded pointmass. Approximations simplify the model into two nonlinear ordinary differential equations, describing motions...... of the system at near-resonant excitation of a single beam mode. This simplified model is studied numerically and analytically, and tested against laboratory experiments. The experiments provide evidence that the simplified mathematical model retains those features of the real system that are necessary...

  2. Setup for Fission and Evaporation Cross-Section Measurements in Reactions Induced by Secondary Beams

    CERN Document Server

    Hassan, A A; Kalpakchieva, R; Skobelev, N K; Penionzhkevich, Yu E; Dlouhý, Z; Radnev, S; Poroshin, N V

    2002-01-01

    A setup for studying reactions induced by secondary radioactive beams has been constructed. It allows simultaneous measurement of alpha-particle and fission fragment energy spectra. By measuring the alpha-particles, identification of evaporation residues is achieved. A set of three targets can be used so as to ensure sufficient statistics. Two silicon detectors, located at 90 degrees to the secondary beam direction, face each target, thus covering 30 % of the solid angle. This experimental setup is to be used to obtain excitation functions of fusion?fission reactions and of reactions leading to evaporation residue production.

  3. The ultraviolet and blue luminescence properties of ZnO:Zn thin film

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The ultraviolet (UV) and blue luminescence of Zn-rich zinc oxide thin film deposited by electron-beam evaporation have been investigated at room temperature (RT). We observed that the UV and blue electroluminescence (EL) emission band centered around 480 nm which is blue shifted in comparison with that of the ZnO thin film prepared by low pressure metal organic chemical vapor deposition (LP MOCVD). The UV emission is much stronger than blue emission in the photoluminescence (PL) spectra. The field-induced ionization of excited luminescent centers of ZnO:Zn thin film at high electric field and the difference between PL and EL are discussed. The experiments show that the ZnO:Zn thin film provides a hopeful new mechanism to obtain UV and blue emission.

  4. Fibre-Coupling Zig-Zag Beam Deflection Technology for Investigation of Attenuation Process of Laser-Induced Shock Waves

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping; BIAN Bao-Min; LI Zhen-Hua

    2005-01-01

    @@ A novel fibre-coupling zig-zag beam deflection technology is developed to investigate the attenuation process of laser-induced shock waves in air. Utilizing ordinal reflections of probe beams by a pair of parallel mirrors,a zig-zag beam field is formed, which has eleven probe beams in the horizontal plane. When a laser-induced shock wave propagates through the testing field, it causes eleven deflection signals one after another. The whole attenuation process of the shock wave in air can be detected and illuminated clearly on one experimental curve.

  5. Studies on transmitted beam modulation effect from laser induced damage on fused silica optics.

    Science.gov (United States)

    Zheng, Yi; Ma, Ping; Li, Haibo; Liu, Zhichao; Chen, Songlin

    2013-07-15

    UV laser induced damage (LID) on exit surface of fused silica could cause modulation effect to transmitted beam and further influence downstream propagation properties. This paper presents our experimental and analytical studies on this topic. In experiment, a series of measurement instruments are applied, including beam profiler, interferometer, microscope, and optical coherent tomography (OCT). Creating and characterizing of LID on fused silica sample have been implemented. Morphological features are studied based on their particular modulation effects on transmitted beam. In theoretical investigation, analytical modeling and numerical simulation are performed. Modulation effects from amplitude, phase, and size factors are analyzed respectively. Furthermore, we have novelly designed a simplified polygon model to simulate actual damage site with multiform modulation features, and the simulation results demonstrate that the modeling is usable and representative.

  6. Beam induced heat loads on the beam-screens of the twin-bore magnets in the IRs of the HL-LHC

    CERN Document Server

    Iadarola, Giovanni; Rumolo, Giovanni

    2016-01-01

    The expected heat load induced on the beam screens has been evaluated for all the twin-bore magnets in the Insertion Regions (IRs) of the HL-LHC. The contribution from the impedance of the beam screen has been evaluated taking into account the presence of a longitudinal weld in the beam screen and the impact of the temperature and of the magnetic field on the resistivity of the surface. The contribution coming from electron cloud effects has been evaluated for different values of the Secondary Electron Yield of the surface based PyECLOUD build-up simulations.

  7. Nanodot and nanocrystal pattern formation and luminescent properties of BiB{sub 3}O{sub 6} glasses after moderate energy ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Plaza, J.L., E-mail: joseluis.plaza@uam.es [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Martinez, O., E-mail: oscar@fmc.uva.es [GdS-Optronlab, Dpto. Fisica Materia Condensada, Universidad de Valladolid, Edificio I-D, Paseo de Belen 1, 47011 Valladolid (Spain); Hortelano, V., E-mail: vhorsan@gmail.com [GdS-Optronlab, Dpto. Fisica Materia Condensada, Universidad de Valladolid, Edificio I-D, Paseo de Belen 1, 47011 Valladolid (Spain); Bensalah, H., E-mail: bensalahhakima@yahoo.fr [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Dieguez, E., E-mail: ernesto.dieguez@uam.es [Laboratorio de Crecimiento de Cristales, Dpto. de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2012-02-01

    In this work we study the nanopatterning effect on the surface of BIBO glasses by means of Ion Beam Sputtering (IBS), using moderate energy (<5 kV) Ar ions. The analysis, changing the energy of the Ar ions, has demonstrated the formation of nanodots, nanorripples, and nanopyramids. We have also analysed the dependence of the nanopatterns on the sample thickness for the same experimental conditions. The sizes of the nanodots have been analysed by AFM, while their optical properties studied by means of {mu}-Raman/{mu}-photoluminescence techniques.

  8. A comparison of neon versus helium ion beam induced deposition via Monte Carlo simulations.

    Science.gov (United States)

    Timilsina, Rajendra; Smith, Daryl A; Rack, Philip D

    2013-03-22

    The ion beam induced nanoscale synthesis of PtCx (where x ∼ 5) using the trimethyl (methylcyclopentadienyl)platinum(IV) (MeCpPt(IV)Me3) precursor is investigated by performing Monte Carlo simulations of helium and neon ions. The helium beam leads to more lateral growth relative to the neon beam because of its larger interaction volume. The lateral growth of the nanopillars is dominated by molecules deposited via secondary electrons in both the simulations. Notably, the helium pillars are dominated by SE-I electrons whereas the neon pillars are dominated by SE-II electrons. Using a low precursor residence time of 70 μs, resulting in an equilibrium coverage of ∼4%, the neon simulation has a lower deposition efficiency (3.5%) compared to that of the helium simulation (6.5%). At larger residence time (10 ms) and consequently larger equilibrium coverage (85%) the deposition efficiencies of helium and neon increased to 49% and 21%, respectively; which is dominated by increased lateral growth rates leading to broader pillars. The nanoscale growth is further studied by varying the ion beam diameter at 10 ms precursor residence time. The study shows that total SE yield decreases with increasing beam diameters for both the ion types. However, helium has the larger SE yield as compared to that of neon in both the low and high precursor residence time, and thus pillars are wider in all the simulations studied.

  9. Toward sensitive graphene nanoribbon-nanopore devices by preventing electron beam-induced damage.

    Science.gov (United States)

    Puster, Matthew; Rodríguez-Manzo, Julio A; Balan, Adrian; Drndić, Marija

    2013-12-23

    Graphene-based nanopore devices are promising candidates for next-generation DNA sequencing. Here we fabricated graphene nanoribbon-nanopore (GNR-NP) sensors for DNA detection. Nanopores with diameters in the range 2-10 nm were formed at the edge or in the center of graphene nanoribbons (GNRs), with widths between 20 and 250 nm and lengths of 600 nm, on 40 nm thick silicon nitride (SiN(x)) membranes. GNR conductance was monitored in situ during electron irradiation-induced nanopore formation inside a transmission electron microscope (TEM) operating at 200 kV. We show that GNR resistance increases linearly with electron dose and that GNR conductance and mobility decrease by a factor of 10 or more when GNRs are imaged at relatively high magnification with a broad beam prior to making a nanopore. By operating the TEM in scanning TEM (STEM) mode, in which the position of the converged electron beam can be controlled with high spatial precision via automated feedback, we were able to prevent electron beam-induced damage and make nanopores in highly conducting GNR sensors. This method minimizes the exposure of the GNRs to the beam before and during nanopore formation. The resulting GNRs with unchanged resistances after nanopore formation can sustain microampere currents at low voltages (∼50 mV) in buffered electrolyte solution and exhibit high sensitivity, with a large relative change of resistance upon changes of gate voltage, similar to pristine GNRs without nanopores.

  10. Electron-beam induced deposition and autocatalytic decomposition of Co(CO3NO

    Directory of Open Access Journals (Sweden)

    Florian Vollnhals

    2014-07-01

    Full Text Available The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID and electron beam-induced surface activation (EBISA is studied for two precursors: iron pentacarbonyl, Fe(CO5, and cobalt tricarbonyl nitrosyl, Co(CO3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM and scanning transmission X-ray microscopy (STXM, including near edge X-ray absorption fine structure (NEXAFS spectroscopy. It has previously been shown that Fe(CO5 decomposes autocatalytically on Fe seed layers (EBID and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO3NO and compare it to results obtained from Fe(CO5. Co(CO3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures.

  11. Electron-beam induced deposition and autocatalytic decomposition of Co(CO)3NO

    Science.gov (United States)

    Vollnhals, Florian; Drost, Martin; Tu, Fan; Carrasco, Esther; Späth, Andreas; Fink, Rainer H; Steinrück, Hans-Peter

    2014-01-01

    Summary The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID) and electron beam-induced surface activation (EBISA) is studied for two precursors: iron pentacarbonyl, Fe(CO)5, and cobalt tricarbonyl nitrosyl, Co(CO)3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM), including near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It has previously been shown that Fe(CO)5 decomposes autocatalytically on Fe seed layers (EBID) and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO)3NO and compare it to results obtained from Fe(CO)5. Co(CO)3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO)5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO)3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures. PMID:25161851

  12. Electron-beam induced deposition and autocatalytic decomposition of Co(CO)3NO.

    Science.gov (United States)

    Vollnhals, Florian; Drost, Martin; Tu, Fan; Carrasco, Esther; Späth, Andreas; Fink, Rainer H; Steinrück, Hans-Peter; Marbach, Hubertus

    2014-01-01

    The autocatalytic growth of arbitrarily shaped nanostructures fabricated by electron beam-induced deposition (EBID) and electron beam-induced surface activation (EBISA) is studied for two precursors: iron pentacarbonyl, Fe(CO)5, and cobalt tricarbonyl nitrosyl, Co(CO)3NO. Different deposits are prepared on silicon nitride membranes and silicon wafers under ultrahigh vacuum conditions, and are studied by scanning electron microscopy (SEM) and scanning transmission X-ray microscopy (STXM), including near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It has previously been shown that Fe(CO)5 decomposes autocatalytically on Fe seed layers (EBID) and on certain electron beam-activated surfaces, yielding high purity, polycrystalline Fe nanostructures. In this contribution, we investigate the growth of structures from Co(CO)3NO and compare it to results obtained from Fe(CO)5. Co(CO)3NO exhibits autocatalytic growth on Co-containing seed layers prepared by EBID using the same precursor. The growth yields granular, oxygen-, carbon- and nitrogen-containing deposits. In contrast to Fe(CO)5 no decomposition on electron beam-activated surfaces is observed. In addition, we show that the autocatalytic growth of nanostructures from Co(CO)3NO can also be initiated by an Fe seed layer, which presents a novel approach to the fabrication of layered nanostructures.

  13. Strain-dependent conductivity of granular metals prepared by focused particle beam induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, Christina; Baranowski, Markus; Huth, Michael [Physikalisches Institut, Goethe-Universitaet, Frankfurt am Main (Germany); Voelklein, Friedemann [Institut fuer Mikrotechnologien, Hochschule RheinMain, Ruesselsheim (Germany)

    2010-07-01

    We report on the strain-dependence of the electrical conductivity of granular metals prepared by focused particle beam induced deposition. The samples were prepared in a dual-beam electron / Ga ion scanning microscope using selected precursors, such as W(CO){sub 6}. Stripe-like deposits were fabricated on dedicated cantilevers pre-patterned with contact pads made from Cr/Au. The cantilever deflection was induced in-situ by means of a four axes nano-manipulator and the conductivity change was recorded by lock-in technique employing a Wheatstone resistance bridge. Current-voltage characteristics and strain-dependence were measured for samples of various thicknesses and composition. For selected samples time-dependent conductivity data were taken as the samples were slowly exposed to air.

  14. Defect-Related Luminescent Hydroxyapatite-Enhanced Osteogenic Differentiation of Bone Mesenchymal Stem Cells Via an ATP-Induced cAMP/PKA Pathway.

    Science.gov (United States)

    Wang, Chao; Liu, Dandan; Zhang, Cuimiao; Sun, Jiadong; Feng, Weipei; Liang, Xing-Jie; Wang, Shuxiang; Zhang, Jinchao

    2016-05-11

    Novel defect-related hydroxyapatite (DHAP), which combines the advantages of HAP and defect-related luminescence, has the potential application in tissue engineering and biomedical area, because of its excellent capability of monitoring the osteogenic differentiation and material biodegradation. Although the extracellular mechanism of DHAP minerals and PO4(3-) functioning in osteogenic differentiation has been widely studied, the intracellular molecular mechanism through which PO4(3-) mediates osteogenesis of bone mesenchymal stem cells (BMSCs) is not clear. We examined a previously unknown molecular mechanism through which PO4(3-) promoted osteogenesis of BMSCs with an emphasis on adenosine-triphosphate (ATP)-induced cAMP/PKA pathway. Our studies showed that DHAP could be uptaken into lysosome, in which PO4(3-) was released from DHAP, because of the acid environment of lysosome. The released PO4(3-) interacted with ADP to form ATP, and then degraded into adenosine, an ATP metabolite, which interacted with A2b adenosine receptor to activate the cAMP/PKA pathway, resulting in the high expression of osteogenesis-related genes, such as Runx2, BMP-2, and OCN. These findings first revealed the function of ATP-metabolism in bone physiological homeostasis, which may be developed to cure bone metabolic diseases.

  15. Advanced ion beam analysis of materials using ion-induced fast electron

    Energy Technology Data Exchange (ETDEWEB)

    Kudo, Hiroshi; Tanabe, Atsushi; Ishihara, Toyoyuki [Tsukuba Univ., Ibaraki (Japan)] [and others

    1997-03-01

    Recent progress in the study of high-energy shadowing effect using ion-induced electron spectroscopy is reported with emphasis on a possibility of determination of local electronic structure in solids, which has been a difficult problem to approach with other experimental techniques. We demonstrate real-space determination of covalent-bond electron distribution in Si crystal. The analysis technique may provide a new field of ion beam analysis of solids. (author)

  16. ION-BEAM INDUCED GENERATION OF CU ADATOMS ON CU(100)

    NARCIS (Netherlands)

    BREEMAN, M; BOERMA, DO

    1992-01-01

    Low-energy ion scattering was used to study on-beam induced adatom generation during irradiation of a Cu(100) surface with 6 keV Ne ions at a sample temperature of 60 K. It was found that the number of adatoms produced per incoming ion decreases from an average of 3.5 to a saturation level of 1.8 af

  17. Comparative dose evaluations between XVI and OBI cone beam CT systems using Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)

    2013-06-15

    Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.5) CBCT imaging protocols using these two types of dosimeters. Methods: Gafchromic XRQA2 film and nanoDot OSLD dose response curves were generated at different kV imaging settings used by XVI (software version R4.5) and OBI (software version 1.5) CBCT systems. The settings for the XVI system were: 100 kVp/F0 (no filter), 120 kVp/F0, and 120 kVp/F1 (Bowtie filter), and for the OBI system were: 100 kVp/full fan, 125 kVp/full fan, and 125 kVp/half fan. XRQA2 film was calibrated in air to air kerma levels between 0 and 11 cGy and scanned using reflection scanning mode with the Epson Expression 10000 XL flat-bed document scanner. NanoDot OSLDs were calibrated on phantom to surface dose levels between 0 and 14 cGy and read using the inLight{sup TM} MicroStar reader. Both dosimeters were used to measure in field surface and internal doses in a male Alderson Rando Phantom. Results: Dose response curves of XRQA2 film and nanoDot OSLDs at different XVI and OBI CBCT settings were reported. For XVI system, the surface dose ranged between 0.02 cGy in head region during fast head and neck scan and 4.99 cGy in the chest region during symmetry scan. On the other hand, the internal dose ranged between 0.02 cGy in the head region during fast head and neck scan and 3.17 cGy in the chest region during chest M20 scan. The average (internal and external) dose ranged between 0.05 cGy in the head region during fast head and neck scan and 2.41 cGy in the chest region during chest M20 scan. For OBI system, the surface dose ranged between 0.19 cGy in head region during head scan and 4.55 cGy in the pelvis region during

  18. Bifunctional Zn(II)Ln(III) dinuclear complexes combining field induced SMM behavior and luminescence: enhanced NIR lanthanide emission by 9-anthracene carboxylate bridging ligands.

    Science.gov (United States)

    Palacios, María A; Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Pope, Simon J A; Brechin, Euan K; Colacio, Enrique

    2014-02-03

    There were new dinuclear Zn(II)-Ln(III) complexes of general formulas [Zn(μ-L)(μ-OAc)Ln(NO3)2] (Ln(III) = Tb (1), Dy (2), Er (3), and Yb (4)), [Zn(μ-L)(μ-NO3)Er(NO3)2] (5), [Zn(H2O)(μ-L)Nd(NO3)3]·2CH3OH (6), [Zn(μ-L)(μ-9-An)Ln(NO3)2]·2CH3CN (Ln(III) = Tb (7), Dy (8), Er (9), Yb(10)), [Zn(μ-L)(μ-9-An)Yb(9-An)(NO3)3]·3CH3CN (11), [Zn(μ-L)(μ-9-An)Nd(9-An)(NO3)3]·2CH3CN·3H2O (12), and [Zn(μ-L)(μ-9-An)Nd(CH3OH)2(NO3)]ClO4·2CH3OH (13) prepared from the reaction of the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H2L), with ZnX2·nH2O (X = NO3(-) or OAc(-)) salts, Ln(NO3)3·nH2O, and, in some instances, 9-anthracenecarboxylate anion (9-An). In all these complexes, the Zn(II) ions invariably occupy the internal N3O2 site whereas the Ln(III) ions show preference for the O4 external site, giving rise to a Zn(μ-diphenoxo)Ln bridging fragment. Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes 1-4, diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes 8-13. Dy(III) and Er(III) complexes 2, 8 and 3, 5, respectively, exhibit field induced single molecule magnet (SMM) behavior, with Ueff values ranging from 11.7 (3) to 41(2) K. Additionally, the solid-state photophysical properties of these complexes are presented showing that ligand L(2-) is able to sensitize Tb(III)- and Dy(III)-based luminescence in the visible region through an energy transfer process (antenna effect). The efficiency of this process is much lower when NIR emitters such as Er(III), Nd(III), and Yb(III) are considered. When the luminophore 9-anthracene carboxylate is incorporated into these complexes, the NIR luminescence is enhanced which proves the efficiency of this bridging ligand to act as antenna group. Complexes 2, 3, 5, and 8 can be considered as dual materials

  19. Electron beam induced evolution in Au, Ag, and interfaced heterogeneous Au/Ag nanoparticles.

    Science.gov (United States)

    Liu, Yuzi; Sun, Yugang

    2015-08-28

    A sintering process of nanoparticles made of Ag, Au, and interfaced Ag/Au heterodimers was investigated by in situ transmission electron microscopy at room temperature. Such a process is driven by the illumination of a high-energy electron beam accelerated at 200 kV that promotes atom diffusion in the nanoparticles that are in physical contact. Upon electron illumination, adjacent Au nanoparticles gradually merge together to form a larger particle along with the reduction of the surface area despite the fact that orientated attachment is not observed. According to the detailed analysis of the size change of the particles and the contact area, it was found that the nanoparticle fusion process is significantly different from the well-established thermal diffusion mechanism. In addition to the similar fusion process of Au nanoparticles, Ag nanoparticles undergo apparent sublimation induced by knock on damage because the transferred energy from the electron beam to nanoparticles is higher than the surface binding energy of Ag atoms when the electron scattering angle is larger than 112°. The particles with a smaller size diffuse faster. Surface diffusion dominates at the beginning of the fusion process followed by slower lattice diffusion. Electron beam illumination can transform the interfaced Au/Ag dimers to Au@Ag core-shell particles followed by a slow removal of the Ag shells. This process under normal electron beam illumination is a lot faster than the thermally driven process. Both diffusion and sublimation of Ag atoms are dependent on the intensity of the electron beam, i.e., a higher beam intensity is favorable to accelerate both the processes.

  20. Exact analytical solution of shear-induced flexural vibration of functionally graded piezoelectric beam

    Science.gov (United States)

    Sharma, Pankaj; Parashar, Sandeep Kumar

    2016-05-01

    The priority of this paper is to obtain the exact analytical solution for free flexural vibration of FGPM beam actuated using the d15 effect. In piezoelectric actuators, the potential use of d15 effect has been of particular interest for engineering applications since shear piezoelectric coefficient d15 is much higher than the other piezoelectric coupling constants d31 and d33. The applications of shear actuators are to induce and control the flexural vibrations of beams and plates. In this study, a modified Timoshenko beam theory is used where electric potential is assumed to vary sinusoidaly along the thickness direction. The material properties are assumed to be graded across the thickness in accordance with power law distribution. Hamilton`s principle is employed to obtain the equations of motion along with the associated boundary conditions for FGPM beams. Exact analytical solution is derived thus obtained equations of motion. Results for clamped-clamped and clamped-free boundary conditions are presented. The presented result and method shell serve as benchmark for comparing the results obtained from the other approximate methods.

  1. In-beam PET measurement of $^{7}Li^{3+}$ irradiation induced $\\beta^+}$-activity

    CERN Document Server

    Priegnitz, M; Parodi, K; Sommerer, F; Fiedler, F; Enghardt, W

    2008-01-01

    At present positron emission tomography (PET) is the only feasible method of an in situ and non-invasive monitoring of patient irradiation with ions. At the experimental carbon ion treatment facility of the Gesellschaft für Schwerionenforschung (GSI) Darmstadt an in-beam PET scanner has been integrated into the treatment site and lead to a considerable quality improvement of the therapy. Since ions other than carbon are expected to come into operation in future patient treatment facilities, it is highly desirable to extend in-beam PET also to other therapeutic relevant ions, e.g. 7Li. Therefore, by means of the in-beam PET scanner at GSI the β+-activity induced by 7Li3+ ions has been investigated for the first time. Targets of PMMA, water, graphite and polyethylene were irradiated with monoenergetic, pencil-like beams of 7Li3+ with energies between 129.1 A MeV and 205.3 A MeV and intensities ranging from 3.0 × 107 to 1.9 × 108 ions s−1. This paper presents the measured β+-activity profiles as well as d...

  2. Nano-ranged low-energy ion-beam-induced DNA transfer in biological cells

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-15

    Low-energy ion beams at a few tens of keV were demonstrated to be able to induce exogenous macromolecules to transfer into plant and bacterial cells. In the process, the ion beam with well controlled energy and fluence bombarded living cells to cause certain degree damage in the cell envelope in nanoscales to facilitate the macromolecules such as DNA to pass through the cell envelope and enter the cell. Consequently, the technique was applied for manipulating positive improvements in the biological species. This physical DNA transfer method was highly efficient and had less risk of side-effects compared with chemical and biological methods. For better understanding of mechanisms involved in the process, a systematic study on the mechanisms was carried out. Applications of the technique were also expanded from DNA transfer in plant and bacterial cells to DNA transfection in human cancer cells potentially for the stem cell therapy purpose. Low-energy nitrogen and argon ion beams that were applied in our experiments had ranges of 100 nm or less in the cell envelope membrane which was majorly composed of polymeric cellulose. The ion beam bombardment caused chain-scission dominant damage in the polymer and electrical property changes such as increase in the impedance in the envelope membrane. These nano-modifications of the cell envelope eventually enhanced the permeability of the envelope membrane to favor the DNA transfer. The paper reports details of our research in this direction.

  3. Nano-ranged low-energy ion-beam-induced DNA transfer in biological cells

    Science.gov (United States)

    Yu, L. D.; Wongkham, W.; Prakrajang, K.; Sangwijit, K.; Inthanon, K.; Thongkumkoon, P.; Wanichapichart, P.; Anuntalabhochai, S.

    2013-06-01

    Low-energy ion beams at a few tens of keV were demonstrated to be able to induce exogenous macromolecules to transfer into plant and bacterial cells. In the process, the ion beam with well controlled energy and fluence bombarded living cells to cause certain degree damage in the cell envelope in nanoscales to facilitate the macromolecules such as DNA to pass through the cell envelope and enter the cell. Consequently, the technique was applied for manipulating positive improvements in the biological species. This physical DNA transfer method was highly efficient and had less risk of side-effects compared with chemical and biological methods. For better understanding of mechanisms involved in the process, a systematic study on the mechanisms was carried out. Applications of the technique were also expanded from DNA transfer in plant and bacterial cells to DNA transfection in human cancer cells potentially for the stem cell therapy purpose. Low-energy nitrogen and argon ion beams that were applied in our experiments had ranges of 100 nm or less in the cell envelope membrane which was majorly composed of polymeric cellulose. The ion beam bombardment caused chain-scission dominant damage in the polymer and electrical property changes such as increase in the impedance in the envelope membrane. These nano-modifications of the cell envelope eventually enhanced the permeability of the envelope membrane to favor the DNA transfer. The paper reports details of our research in this direction.

  4. Sensitivity Jump of Micro Accelerometer Induced by Micro-fabrication Defects of Micro Folded Beams

    Directory of Open Access Journals (Sweden)

    Zhou Wu

    2016-08-01

    Full Text Available The abnormal phenomenon occurring in sensor calibration is an obstacle to product development but a useful guideline to product improvement. The sensitivity jump of micro accelerometers in the calibrating process is recognized as an important abnormal behavior and investigated in this paper. The characteristics of jumping output in the centrifuge test are theoretically and experimentally analyzed and their underlying mechanism is found to be related to the varied stiffness of supporting beam induced by the convex defect on it. The convex defect is normally formed by the lithography deviation and/or etching error and can result in a jumping stiffness of folded microbeams and further influence the sensitivity when a part of the bending beams is stopped from moving by two surfaces contacting. The jumping level depends on the location of convex and has nothing to do with the contacting properties of beam and defects. Then the location of defect is predicted by theoretical model and simulation and verified by the observation of micro structures under microscopy. The results indicate that the tested micro accelerometer has its defect on the beam with a distance of about 290μm from the border of proof mass block.

  5. Effects of electrons on the shape of nanopores prepared by focused electron beam induced etching

    Science.gov (United States)

    Liebes, Yael; Hadad, Binyamin; Ashkenasy, Nurit

    2011-07-01

    The fabrication of nanometric pores with controlled size is important for applications such as single molecule detection. We have recently suggested the use of focused electron beam induced etching (FEBIE) for the preparation of such nanopores in silicon nitride membranes. The use of a scanning probe microscope as the electron beam source makes this technique comparably accessible, opening the way to widespread fabrication of nanopores. Since the shape of the nanopores is critically important for their performance, in this work we focus on its analysis and study the dependence of the nanopore shape on the electron beam acceleration voltage. We show that the nanopore adopts a funnel-like shape, with a central pore penetrating the entire membrane, surrounded by an extended shallow-etched region at the top of the membrane. While the internal nanopore size was found to depend on the electron acceleration voltage, the nanopore edges extended beyond the primary electron beam spot size due to long-range effects, such as radiolysis and diffusion. Moreover, the size of the peripheral-etched region was found to be less dependent on the acceleration voltage. We also found that chemical etching is the rate-limiting step of the process and is only slightly dependent on the acceleration voltage. Furthermore, due to the chemical etch process the chemical composition of the nanopore rims was found to maintain the bulk membrane composition.

  6. Effects of electrons on the shape of nanopores prepared by focused electron beam induced etching

    Energy Technology Data Exchange (ETDEWEB)

    Liebes, Yael; Ashkenasy, Nurit [Department of Materials Engineering, Ben-Gurion University of the Negev, PO Box 653 Beer-Sheva (Israel); Hadad, Binyamin, E-mail: nurita@bgu.ac.il [The Ilze Kaz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, PO Box 653 Beer-Sheva (Israel)

    2011-07-15

    The fabrication of nanometric pores with controlled size is important for applications such as single molecule detection. We have recently suggested the use of focused electron beam induced etching (FEBIE) for the preparation of such nanopores in silicon nitride membranes. The use of a scanning probe microscope as the electron beam source makes this technique comparably accessible, opening the way to widespread fabrication of nanopores. Since the shape of the nanopores is critically important for their performance, in this work we focus on its analysis and study the dependence of the nanopore shape on the electron beam acceleration voltage. We show that the nanopore adopts a funnel-like shape, with a central pore penetrating the entire membrane, surrounded by an extended shallow-etched region at the top of the membrane. While the internal nanopore size was found to depend on the electron acceleration voltage, the nanopore edges extended beyond the primary electron beam spot size due to long-range effects, such as radiolysis and diffusion. Moreover, the size of the peripheral-etched region was found to be less dependent on the acceleration voltage. We also found that chemical etching is the rate-limiting step of the process and is only slightly dependent on the acceleration voltage. Furthermore, due to the chemical etch process the chemical composition of the nanopore rims was found to maintain the bulk membrane composition.

  7. Investigation of focused ion beam induced damage in single crystal diamond tools

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Zhen [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Luo, Xichun, E-mail: Xichun.Luo@strath.ac.uk [Centre for Precision Manufacturing, Department of Design, Manufacture & Engineering Management, University of Strathclyde, Glasgow G1 1XQ (United Kingdom)

    2015-08-30

    Highlights: • The FIB-induced damage layer should be paid enough attention when shaping the cutting edges of nanoscale diamond tools. • During FIB processing cutting tools made of natural single crystal diamond, the Ga{sup +} collision will create a damage layer around tool tips. • The thicknesses of damaged layer and the level for amorphization of diamond significantly increase with beam energy. • The FIB-induced doping and defects during tool fabrication are responsible for the early detection of tool wear of nanoscale diamond tools. - Abstract: In this work, transmission electron microscope (TEM) measurements and molecular dynamics (MD) simulations were carried out to characterise the focused ion beam (FIB) induced damage layer in a single crystal diamond tool under different FIB processing voltages. The results obtained from the experiments and the simulations are in good agreement. The results indicate that during FIB processing cutting tools made of natural single crystal diamond, the energetic Ga{sup +} collision will create an impulse-dependent damage layer at the irradiated surface. For the tested beam voltages in a typical FIB system (from 8 kV to 30 kV), the thicknesses of the damaged layers formed on a diamond tool surface increased from 11.5 nm to 27.6 nm. The dynamic damage process of FIB irradiation and ion–solid interactions physics leading to processing defects in FIB milling were emulated by MD simulations. The research findings from this study provide the in-depth understanding of the wear of nanoscale multi-tip diamond tools considering the FIB irradiation induced doping and defects during the tool fabrication process.

  8. Characterisation and mitigation of beam-induced backgrounds observed in the ATLAS detector during the 2011 proton-proton run

    CERN Document Server

    Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; Åkesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Andrieux, Marie-Laure; Anduaga, Xabier; Angelidakis, Stylianos; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Ask, Stefan; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Backus Mayes, John; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Balek, Petr; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Behera, Prafulla; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bittner, Bernhard; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges; Blazek, Tomas; Bloch, Ingo; Blocker, Craig; Blocki, Jacek; Blondel, Alain; Blum, Walter; Blumenschein, Ulrike; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Boddy, Christopher Richard; Boehler, Michael; Boek, Jennifer; Boek, Thorsten Tobias; Boelaert, Nele; Bogaerts, Joannes Andreas; Bogdanchikov, Alexander; Bogouch, Andrei; Bohm, Christian; Bohm, Jan; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Bolnet, Nayanka Myriam; Bomben, Marco; Bona, Marcella; Boonekamp, Maarten; Bordoni, Stefania; Borer, Claudia; Borisov, Anatoly; Borissov, Guennadi; Borjanovic, Iris; Borri, Marcello; Borroni, Sara; Bortfeldt, Jonathan; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boterenbrood, Hendrik; Bouchami, Jihene; Boudreau, Joseph; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozovic-Jelisavcic, Ivanka; Bracinik, Juraj; Branchini, Paolo; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Brazzale, Simone Federico; Brelier, Bertrand; Bremer, Johan; Brendlinger, Kurt; Brenner, Richard; Bressler, Shikma; Britton, Dave; Brochu, Frederic; Brock, Ian; Brock, Raymond; Broggi, Francesco; Bromberg, Carl; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, Timothy; Brooks, William; Brown, Gareth; Brown, Heather; Bruce, Roderik; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Brunet, Sylvie; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Buanes, Trygve; Buat, Quentin; Bucci, Francesca; Buchanan, James; Buchholz, Peter; Buckingham, Ryan; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Budick, Burton; Büscher, Volker; Bugge, Lars; Bulekov, Oleg; Bundock, Aaron Colin; Bunse, Moritz; Buran, Torleiv; Burckhart, Helfried; Burdin, Sergey; Burgess, Thomas; Burke, Stephen; Busato, Emmanuel; Bussey, Peter; Buszello, Claus-Peter; Butler, Bart; Butler, John; Buttar, Craig; Butterworth, Jonathan; Buttinger, William; Byszewski, Marcin; Cabrera Urbán, Susana; Caforio, Davide; Cakir, Orhan; Calafiura, Paolo; Calderini, Giovanni; Calfayan, Philippe; Calkins, Robert; Caloba, Luiz; Caloi, Rita; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarri, Paolo; Cameron, David; Caminada, Lea Michaela; Caminal Armadans, Roger; Campana, Simone; Campanelli, Mario; Canale, Vincenzo; Canelli, Florencia; Canepa, Anadi; Cantero, Josu; Cantrill, Robert; Capasso, Luciano; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capriotti, Daniele; Capua, Marcella; Caputo, Regina; Cardarelli, Roberto; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Bryan; Caron, Sascha; Carquin, Edson; Carrillo-Montoya, German D; Carter, Antony; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Cascella, Michele; Caso, Carlo; Castaneda Hernandez, Alfredo Martin; Castaneda-Miranda, Elizabeth; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Cataldi, Gabriella; Catastini, Pierluigi; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Cattani, Giordano; Caughron, Seth; Cavaliere, Viviana; Cavalleri, Pietro; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Cerqueira, Augusto Santiago; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cetin, Serkant Ali; Chafaq, Aziz; Chakraborty, Dhiman; Chalupkova, Ina; Chan, Kevin; Chang, Philip; Chapleau, Bertrand; Chapman, John Derek; Chapman, John Wehrley; Chareyre, Eve; Charlton, Dave; Chavda, Vikash; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Shenjian; Chen, Xin; Chen, Yujiao; Cheng, Yangyang; Cheplakov, Alexander; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Cheung, Sing-Leung; Chevalier, Laurent; Chiefari, Giovanni; Chikovani, Leila; Childers, John Taylor; Chilingarov, Alexandre; Chiodini, Gabriele; Chisholm, Andrew; Chislett, Rebecca Thalatta; Chitan, Adrian; Chizhov, Mihail; Choudalakis, Georgios; Chouridou, Sofia; Christidi, Ilektra-Athanasia; Christov, Asen; Chromek-Burckhart, Doris; Chu, Ming-Lee; Chudoba, Jiri; Ciapetti, Guido; Ciftci, Abbas Kenan; Ciftci, Rena; Cinca, Diane; Cindro, Vladimir; Ciocca, Claudia; Ciocio, Alessandra; Cirilli, Manuela; Cirkovic, Predrag; Citron, Zvi Hirsh; Citterio, Mauro; Ciubancan, Mihai; Clark, Allan G; Clark, Philip James; Clarke, Robert; Cleland, Bill; Clemens, Jean-Claude; Clement, Benoit; Clement, Christophe; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Coffey, Laurel; Cogan, Joshua Godfrey; Coggeshall, James; Cogneras, Eric; Colas, Jacques; Cole, Stephen; Colijn, Auke-Pieter; Collins, Neil; Collins-Tooth, Christopher; Collot, Johann; Colombo, Tommaso; Colon, German; Compostella, Gabriele; Conde Muiño, Patricia; Coniavitis, Elias; Conidi, Maria Chiara; Consonni, Sofia Maria; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conti, Geraldine; Conventi, Francesco; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Copic, Katherine; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Côté, David; Courneyea, Lorraine; Cowan, Glen; Cowden, Christopher; Cox, Brian; Cranmer, Kyle; Crescioli, Francesco; Cristinziani, Markus; Crosetti, Giovanni; Crépé-Renaudin, Sabine; Cuciuc, Constantin-Mihai; Cuenca Almenar, Cristóbal; Cuhadar Donszelmann, Tulay; Cummings, Jane; Curatolo, Maria; Curtis, Chris; Cuthbert, Cameron; Cwetanski, Peter; Czirr, Hendrik; Czodrowski, Patrick; Czyczula, Zofia; D'Auria, Saverio; D'Onofrio, Monica; D'Orazio, Alessia; Da Cunha Sargedas De Sousa, Mario Jose; Da Via, Cinzia; Dabrowski, Wladyslaw; Dafinca, Alexandru; Dai, Tiesheng; Dallapiccola, Carlo; Dam, Mogens; Dameri, Mauro; Damiani, Daniel; Danielsson, Hans Olof; Dao, Valerio; Darbo, Giovanni; Darlea, Georgiana Lavinia; Dassoulas, James; Davey, Will; Davidek, Tomas; Davidson, Nadia; Davidson, Ruth; Davies, Eleanor; Davies, Merlin; Davignon, Olivier; Davison, Adam; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Castro, Stefano; De Cecco, Sandro; de Graat, Julien; De Groot, Nicolo; de Jong, Paul; De La Taille, Christophe; De la Torre, Hector; De Lorenzi, Francesco; de Mora, Lee; De Nooij, Lucie; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; De Zorzi, Guido; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dechenaux, Benjamin; Dedovich, Dmitri; Degenhardt, James; Del Peso, Jose; Del Prete, Tarcisio; Delemontex, Thomas; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delsart, Pierre-Antoine; Deluca, Carolina; Demers, Sarah; Demichev, Mikhail; Demirkoz, Bilge; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Devetak, Erik; Deviveiros, Pier-Olivier; Dewhurst, Alastair; DeWilde, Burton; Dhaliwal, Saminder; Dhullipudi, Ramasudhakar; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Donato, Camilla; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Luise, Silvestro; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Diaz, Marco Aurelio; Diehl, Edward; Dietrich, Janet; Dietzsch, Thorsten; Diglio, Sara; Dindar Yagci, Kamile; Dingfelder, Jochen; Dinut, Florin; Dionisi, Carlo; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; do Vale, Maria Aline Barros; Do Valle Wemans, André; Doan, Thi Kieu Oanh; Dobbs, Matt; Dobos, Daniel; Dobson, Ellie; Dodd, Jeremy; Doglioni, Caterina; Doherty, Tom; Doi, Yoshikuni; Dolejsi, Jiri; Dolenc, Irena; Dolezal, Zdenek; Dolgoshein, Boris; Dohmae, Takeshi; Donadelli, Marisilvia; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dos Anjos, Andre; Dotti, Andrea; Dova, Maria-Teresa; Doxiadis, Alexander; Doyle, Tony; Dressnandt, Nandor; Dris, Manolis; Dubbert, Jörg; Dube, Sourabh; Duchovni, Ehud; Duckeck, Guenter; Duda, Dominik; Dudarev, Alexey; Dudziak, Fanny; Dührssen, Michael; Duerdoth, Ian; Duflot, Laurent; Dufour, Marc-Andre; Duguid, Liam; Dunford, Monica; Duran Yildiz, Hatice; Duxfield, Robert; Dwuznik, Michal; Dydak, Friedrich; Düren, Michael; Ebenstein, William; Ebke, Johannes; Eckweiler, Sebastian; Edmonds, Keith; Edson, William; Edwards, Clive; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Eisenhandler, Eric; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Ellis, Katherine; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Engelmann, Roderich; Engl, Albert; Epp, Brigitte; Erdmann, Johannes; Ereditato, Antonio; Eriksson, Daniel; Ernst, Jesse; Ernst, Michael; Ernwein, Jean; Errede, Deborah; Errede, Steven; Ertel, Eugen; Escalier, Marc; Esch, Hendrik; Escobar, Carlos; Espinal Curull, Xavier; Esposito, Bellisario; Etienne, Francois; Etienvre, Anne-Isabelle; Etzion, Erez; Evangelakou, Despoina; Evans, Hal; Fabbri, Laura; Fabre, Caroline; Fakhrutdinov, Rinat; Falciano, Speranza; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farley, Jason; Farooque, Trisha; Farrell, Steven; Farrington, Sinead; Farthouat, Philippe; Fassi, Farida; Fassnacht, Patrick; Fassouliotis, Dimitrios; Fatholahzadeh, Baharak; Favareto, Andrea; Fayard, Louis; Fazio, Salvatore; Febbraro, Renato; Federic, Pavol; Fedin, Oleg; Fedorko, Wojciech; Fehling-Kaschek, Mirjam; Feligioni, Lorenzo; Feng, Cunfeng; Feng, Eric; Fenyuk, Alexander; Ferencei, Jozef; Fernando, Waruna; Ferrag, Samir; Ferrando, James; Ferrara, Valentina; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filthaut, Frank; Fincke-Keeler, Margret; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Gordon; Fisher, Matthew; Flechl, Martin; Fleck, Ivor; Fleckner, Johanna; Fleischmann, Philipp; Fleischmann, Sebastian; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Fonseca Martin, Teresa; Formica, Andrea; Forti, Alessandra; Fortin, Dominique; Fournier, Daniel; Fowler, Andrew; Fox, Harald; Francavilla, Paolo; Franchini, Matteo; Franchino, Silvia; Francis, David; Frank, Tal; Franklin, Melissa; Franz, Sebastien; Fraternali, Marco; Fratina, Sasa; French, Sky; Friedrich, Conrad; Friedrich, Felix; Froeschl, Robert; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fulsom, Bryan Gregory; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gadfort, Thomas; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Galhardo, Bruno; Gallas, Elizabeth; Gallo, Valentina Santina; Gallop, Bruce; Gallus, Petr; Gan, KK; Gao, Yongsheng; Gaponenko, Andrei; Garberson, Ford; Garcia-Sciveres, Maurice; García, Carmen; García Navarro, José Enrique; Gardner, Robert; Garelli, Nicoletta; Garitaonandia, Hegoi; Garonne, Vincent; Gatti, Claudio; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gauzzi, Paolo; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gazis, Evangelos; Ge, Peng; Gecse, Zoltan; Gee, Norman; Geerts, Daniël Alphonsus Adrianus; Geich-Gimbel, Christoph; Gellerstedt, Karl; Gemme, Claudia; Gemmell, Alistair; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerlach, Peter; Gershon, Avi; Geweniger, Christoph; Ghazlane, Hamid; Ghodbane, Nabil; Giacobbe, Benedetto; Giagu, Stefano; Giakoumopoulou, Victoria; Giangiobbe, Vincent; Gianotti, Fabiola; Gibbard, Bruce; Gibson, Adam; Gibson, Stephen; Gilchriese, Murdock; Gillberg, Dag; Gillman, Tony; Gingrich, Douglas; Ginzburg, Jonatan; Giokaris, Nikos; Giordani, MarioPaolo; Giordano, Raffaele; Giorgi, Francesco Michelangelo; Giovannini, Paola; Giraud, Pierre-Francois; Giugni, Danilo; Giunta, Michele; Gjelsten, Børge Kile; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glazov, Alexandre; Glitza, Karl-Walter; Glonti, George; Goddard, Jack Robert; Godfrey, Jennifer; Godlewski, Jan; Goebel, Martin; Göpfert, Thomas; Goeringer, Christian; Gössling, Claus; Goldfarb, Steven; Golling, Tobias; Gomes, Agostinho; Gomez Fajardo, Luz Stella; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez Silva, Laura; Gonzalez-Sevilla, Sergio; Goodson, Jeremiah Jet; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorfine, Grant; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Goshaw, Alfred; Gosselink, Martijn; Gostkin, Mikhail Ivanovitch; Gough Eschrich, Ivo; Gouighri, Mohamed; Goujdami, Driss; Goulette, Marc Phillippe; Goussiou, Anna; Goy, Corinne; Gozpinar, Serdar; Grabowska-Bold, Iwona; Grafström, Per; Grahn, Karl-Johan; Gramstad, Eirik; Grancagnolo, Francesco; Grancagnolo, Sergio; Grassi, Valerio; Gratchev, Vadim; Grau, Nathan; Gray, Heather; Gray, Julia Ann; Graziani, Enrico; Grebenyuk, Oleg; Greenshaw, Timothy; Greenwood, Zeno Dixon; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grigalashvili, Nugzar; Grillo, Alexander; Grinstein, Sebastian; Gris, Philippe Luc Yves; Grishkevich, Yaroslav; Grivaz, Jean-Francois; Gross, Eilam; Grosse-Knetter, Joern; Groth-Jensen, Jacob; Grybel, Kai; Guest, Daniel; Guicheney, Christophe; Guido, Elisa; Guindon, Stefan; Gul, Umar; Gunther, Jaroslav; Guo, Bin; Guo, Jun; Gutierrez, Phillip; Guttman, Nir; Gutzwiller, Olivier; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haas, Stefan; Haber, Carl; Hadavand, Haleh Khani; Hadley, David; Haefner, Petra; Hahn, Ferdinand; Hajduk, Zbigniew; Hakobyan, Hrachya; Hall, David; Hamacher, Klaus; Hamal, Petr; Hamano, Kenji; Hamer, Matthias; Hamilton, Andrew; Hamilton, Samuel; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Handel, Carsten; Hanke, Paul; Hansen, John Renner; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Peter Henrik; Hansson, Per; Hara, Kazuhiko; Harenberg, Torsten; Harkusha, Siarhei; Harper, Devin; Harrington, Robert; Harris, Orin; Hartert, Jochen; Hartjes, Fred; Haruyama, Tomiyoshi; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hayakawa, Takashi; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; Head, Simon; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heinemann, Beate; Heisterkamp, Simon; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, Robert; Henke, Michael; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Henß, Tobias; Hernandez, Carlos Medina; Hernández Jiménez, Yesenia; Herrberg, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Higón-Rodriguez, Emilio; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirsch, Florian; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hohlfeld, Marc; Holder, Martin; Holmgren, Sven-Olof; Holy, Tomas; Holzbauer, Jenny; Hong, Tae Min; Hooft van Huysduynen, Loek; Horner, Stephan; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huettmann, Antje; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hurwitz, Martina; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibbotson, Michael; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Iengo, Paolo; Igonkina, Olga; Ikegami, Yoichi; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Ince, Tayfun; Inigo-Golfin, Joaquin; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jamin, David Olivier; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Janssen, Jens; Jantsch, Andreas; Janus, Michel; Jared, Richard; Jarlskog, Göran; Jeanty, Laura; Jen-La Plante, Imai; Jennens, David; Jenni, Peter; Loevschall-Jensen, Ask Emil; Jež, Pavel; Jézéquel, Stéphane; Jha, Manoj Kumar; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinnouchi, Osamu; Joergensen, Morten Dam; Joffe, David; Johansen, Marianne; Johansson, Erik; Johansson, Per; Johnert, Sebastian; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Joram, Christian; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Jovin, Tatjana; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Juranek, Vojtech; Jussel, Patrick; Juste Rozas, Aurelio; Kabana, Sonja; Kaci, Mohammed; Kaczmarska, Anna; Kadlecik, Peter; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kalinin, Sergey; Kalinovskaya, Lidia; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kaplon, Jan; Kar, Deepak; Karagounis, Michael; Karakostas, Konstantinos; Karnevskiy, Mikhail; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Mayuko; Kataoka, Yousuke; Katsoufis, Elias; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kayl, Manuel; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Keener, Paul; Kehoe, Robert; Keil, Markus; Kekelidze, George; Keller, John; Kenyon, Mike; Kepka, Oldrich; Kerschen, Nicolas; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharchenko, Dmitri; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klemetti, Miika; Klier, Amit; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Klous, Sander; Kluge, Eike-Erik; Kluge, Thomas; Kluit, Peter; Kluth, Stefan; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Ko, Byeong Rok; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Köneke, Karsten; König, Adriaan; Koenig, Sebastian; Köpke, Lutz; Koetsveld, Folkert; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohn, Fabian; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolachev, Guennady; Kolanoski, Hermann; Kolesnikov, Vladimir; Koletsou, Iro; Koll, James; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kono, Takanori; Kononov, Anatoly; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kreiss, Sven; Krejci, Frantisek; Kretzschmar, Jan; Krieger, Nina; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruse, Mark; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Thorsten; Kuhn, Dietmar; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kummer, Christian; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurata, Masakazu; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwee, Regina; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Labbe, Julien; Lablak, Said; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laisne, Emmanuel; Lambourne, Luke; Lampen, Caleb; Lampl, Walter; Lancon, Eric; Landgraf, Ulrich; Landon, Murrough; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Lanza, Agostino; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Larner, Aimee; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Laycock, Paul; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Michel; Legendre, Marie; Legger, Federica; Leggett, Charles; Lehmacher, Marc; Lehmann Miotto, Giovanna; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Lendermann, Victor; Leney, Katharine; Lenz, Tatiana; Lenzen, Georg; Lenzi, Bruno; Leonhardt, Kathrin; Leontsinis, Stefanos; Lepold, Florian; Leroy, Claude; Lessard, Jean-Raphael; Lester, Christopher; Lester, Christopher Michael; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bo; Li, Haifeng; Li, Ho Ling; Li, Shu; Li, Xuefei; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lichtnecker, Markus; Lie, Ki; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Chuanlei; Liu, Dong; Liu, Hao; Liu, Jianbei; Liu, Lulu; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Lo Sterzo, Francesco; Losty, Michael; Lou, XinChou; Lounis, Abdenour; Loureiro, Karina; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Ludwig, Andreas; Ludwig, Dörthe; Ludwig, Inga; Ludwig, Jens; Luehring, Frederick; Luijckx, Guy; Lukas, Wolfgang; Luminari, Lamberto; Lund, Esben; Lund-Jensen, Bengt; Lundberg, Björn; Lundberg, Johan; Lundberg, Olof; Lundquist, Johan; Lungwitz, Matthias; Lynn, David; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Macina, Daniela; Mackeprang, Rasmus; Madaras, Ronald; Maddocks, Harvey Jonathan; Mader, Wolfgang; Maenner, Reinhard; Maeno, Tadashi; Mättig, Peter; Mättig, Stefan; Magnoni, Luca; Magradze, Erekle; Mahboubi, Kambiz; Mahlstedt, Joern; Mahmoud, Sara; Mahout, Gilles; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Malecki, Piotr; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mameghani, Raphael; Mamuzic, Judita; Manabe, Atsushi; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Manfredini, Alessandro; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mapelli, Alessandro; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marroquim, Fernando; Marshall, Zach; Martens, Kalen; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martin-Haugh, Stewart; Martinez, Mario; Martinez Outschoorn, Verena; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massaro, Graziano; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsunaga, Hiroyuki; Matsushita, Takashi; Mattravers, Carly; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mayne, Anna; Mazini, Rachid; Mazur, Michael; Mazzaferro, Luca; Mazzanti, Marcello; Mc Donald, Jeffrey; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Mechtel, Markus; Medinnis, Mike; Meehan, Samuel; Meera-Lebbai, Razzak; Meguro, Tatsuma; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mendoza Navas, Luis; Meng, Zhaoxia; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer, Joerg; Michal, Sebastien; Micu, Liliana; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Miller, Robert; Mills, Bill; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Moeller, Victoria; Mönig, Klaus; Möser, Nicolas; Mohapatra, Soumya; Mohr, Wolfgang; Moles-Valls, Regina; Molfetas, Angelos; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Moorhead, Gareth; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Morello, Gianfranco; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Mueller, Felix; Mueller, James; Mueller, Klemens; Müller, Thomas; Mueller, Timo; Muenstermann, Daniel; Munwes, Yonathan; Murray, Bill; Mussche, Ido; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nackenhorst, Olaf; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Nanava, Gizo; Napier, Austin; Narayan, Rohin; Nash, Michael; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neusiedl, Andrea; Neves, Ricardo; Nevski, Pavel; Newcomer, Mitchel; Newman, Paul; Nguyen Thi Hong, Van; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Niedercorn, Francois; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsen, Henrik; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Norton, Peter; Novakova, Jana; Nozaki, Mitsuaki; Nozka, Libor; Nugent, Ian Michael; Nuncio-Quiroz, Adriana-Elizabeth; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; O'Brien, Brendan Joseph; O'Neil, Dugan; O'Shea, Val; Oakes, Louise Beth; Oakham, Gerald; Oberlack, Horst; Ocariz, Jose; Ochi, Atsuhiko; Oda, Susumu; Odaka, Shigeru; Odier, Jerome; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohshima, Takayoshi; Okamura, Wataru; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira, Miguel Alfonso; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Orlov, Iliya; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Osuna, Carlos; Otero y Garzon, Gustavo; Ottersbach, John; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Simon; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Paleari, Chiara; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panduro Vazquez, William; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Papadelis, Aras; Papadopoulou, Theodora; Paramonov, Alexander; Paredes Hernandez, Daniela; Park, Woochun; Parker, Michael Andrew; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pashapour, Shabnaz; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pecsy, Martin; Pedraza Lopez, Sebastian; Pedraza Morales, Maria Isabel; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penson, Alexander; Penwell, John; Perantoni, Marcelo; Perez, Kerstin; Perez Cavalcanti, Tiago; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Perrodo, Pascal; Peshekhonov, Vladimir; Peters, Krisztian; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petschull, Dennis; Petteni, Michele; Pezoa, Raquel; Phan, Anna; Phillips, Peter William; Piacquadio, Giacinto; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pinto, Belmiro; Pizio, Caterina; Plamondon, Mathieu; Pleier, Marc-Andre; Plotnikova, Elena; Poblaguev, Andrei; Poddar, Sahill; Podlyski, Fabrice; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polini, Alessandro; Poll, James; Polychronakos, Venetios; Pomeroy, Daniel; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Pretzl, Klaus Peter; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Prudent, Xavier; Przybycien, Mariusz; Przysiezniak, Helenka; Psoroulas, Serena; Ptacek, Elizabeth; Pueschel, Elisa; Purdham, John; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Quadt, Arnulf; Quarrie, David; Quayle, William; Quinonez, Fernando; Raas, Marcel; Radeka, Veljko; Radescu, Voica; Radloff, Peter; Rador, Tonguc; Ragusa, Francesco; Rahal, Ghita; Rahimi, Amir; Rahm, David; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Randrianarivony, Koloina; Rauscher, Felix; Rave, Tobias Christian; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Reinsch, Andreas; Reisinger, Ingo; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rijpstra, Manouk; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Rios, Ryan Randy; Riu, Imma; Rivoltella, Giancesare; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Rocha de Lima, Jose Guilherme; Roda, Chiara; Roda Dos Santos, Denis; Roe, Adam; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosenbaum, Gabriel; Rosenberg, Eli; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rosselet, Laurent; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Ruckstuhl, Nicole; Rud, Viacheslav; Rudolph, Christian; Rudolph, Gerald; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rumyantsev, Leonid; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Rutherfoord, John; Ruzicka, Pavel; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Samset, Björn Hallvard; Sanchez, Arturo; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santamarina Rios, Cibran; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Saraiva, João; Sarangi, Tapas; Sarkisyan-Grinbaum, Edward; Sarrazin, Bjorn; Sarri, Francesca; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Sasao, Noboru; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Sauvan, Jean-Baptiste; Savard, Pierre; Savinov, Vladimir; Savu, Dan Octavian; Sawyer, Lee; Saxon, David; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schäfer, Uli; Schaelicke, Andreas; Schaepe, Steffen; Schaetzel, Sebastian; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R~Dean; Schamov, Andrey; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schneider, Basil; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schroeder, Christian; Schroer, Nicolai; Schultens, Martin Johannes; Schultes, Joachim; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwegler, Philipp; Schwemling, Philippe; Schwienhorst, Reinhard; Schwierz, Rainer; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciacca, Gianfranco; Sciolla, Gabriella; Scott, Bill; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellden, Bjoern; Sellers, Graham; Seman, Michal; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Seuster, Rolf; Severini, Horst; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Sherman, Daniel; Sherwood, Peter; Shimizu, Shima; Shimojima, Makoto; Shin, Taeksu; Shiyakova, Mariya; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Ben Campbell; Smith, Douglas; Smith, Kenway; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snow, Steve; Snow, Joel; Snyder, Scott; Sobie, Randall; Sodomka, Jaromir; Soffer, Abner; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Soni, Nitesh; Sopko, Vit; Sopko, Bruno; Sosebee, Mark; Soualah, Rachik; Soukharev, Andrey; Spagnolo, Stefania; Spanò, Francesco; Spighi, Roberto; Spigo, Giancarlo; Spiwoks, Ralf; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Staude, Arnold; Stavina, Pavel; Steele, Genevieve; Steinbach, Peter; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoerig, Kathrin; Stoicea, Gabriel; Stonjek, Stefan; Strachota, Pavel; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strang, Michael; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Strong, John; Stroynowski, Ryszard; Stugu, Bjarne; Stumer, Iuliu; Stupak, John; Sturm, Philipp; Styles, Nicholas Adam; Soh, Dart-yin; Su, Dong; Subramania, Halasya Siva; Subramaniam, Rajivalochan; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Suzuki, Yuta; Svatos, Michal; Swedish, Stephen; Sykora, Ivan; Sykora, Tomas; Sánchez, Javier; Ta, Duc; Tackmann, Kerstin; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tamsett, Matthew; Tan, Kong Guan; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tardif, Dominique; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tassi, Enrico; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teinturier, Marthe; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tic, Tomáš; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tonoyan, Arshak; Topfel, Cyril; Topilin, Nikolai; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alesandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; True, Patrick; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiakiris, Menelaos; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsung, Jieh-Wen; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuggle, Joseph; Turala, Michal; Turecek, Daniel; Turk Cakir, Ilkay; Turlay, Emmanuel; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Tzanakos, George; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ugland, Maren; Uhlenbrock, Mathias; Uhrmacher, Michael; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Unno, Yoshinobu; Urbaniec, Dustin; Urquijo, Phillip; Usai, Giulio; Uslenghi, Massimiliano; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Vahsen, Sven; Valenta, Jan; Valentinetti, Sara; Valero, Alberto; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Berg, Richard; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Poel, Egge; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; van Vulpen, Ivo; Vanadia, Marco; Vandelli, Wainer; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vassilakopoulos, Vassilios; Vazeille, Francois; Vazquez Schroeder, Tamara; Vegni, Guido; Veillet, Jean-Jacques; Veloso, Filipe; Veness, Raymond; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinek, Elisabeth; Vinogradov, Vladimir; Virchaux, Marc; Virzi, Joseph; Vitells, Ofer; Viti, Michele; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; Volpini, Giovanni; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorwerk, Volker; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Wagner, Wolfgang; Wagner, Peter; Wahlen, Helmut; Wahrmund, Sebastian; Wakabayashi, Jun; Walch, Shannon; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chiho; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Rui; Wang, Song-Ming; Wang, Tan; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; Watanabe, Ippei; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Anthony; Waugh, Ben; Weber, Michele; Weber, Pavel; Webster, Jordan S; Weidberg, Anthony; Weigell, Philipp; Weingarten, Jens; Weiser, Christian; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Werth, Michael; Wessels, Martin; Wetter, Jeffrey; Weydert, Carole; Whalen, Kathleen; White, Andrew; White, Martin; White, Sebastian; Whitehead, Samuel Robert; Whiteson, Daniel; Whittington, Denver; Wicek, Francois; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilhelm, Ivan; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Eric; Williams, Hugh; Willis, William; Willocq, Stephane; Wilson, John; Wilson, Michael Galante; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wong, Wei-Cheng; Wooden, Gemma; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wraight, Kenneth; Wright, Michael; Wrona, Bozydar; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xie, Song; Xu, Chao; Xu, Da; Xu, Lailin; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamazaki, Takayuki; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Un-Ki; Yang, Yi; Yang, Zhaoyu; Yanush, Serguei; Yao, Liwen; Yao, Yushu; Yasu, Yoshiji; Ybeles Smit, Gabriel Valentijn; Ye, Jingbo; Ye, Shuwei; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Rikutaro; Yoshihara, Keisuke; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, Dantong; Yu, Jaehoon; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zajacova, Zuzana; Zanello, Lucia; Zanzi, Daniele; Zaytsev, Alexander; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zendler, Carolin; Zenin, Oleg; Ženiš, Tibor; Zinonos, Zinonas; Zenz, Seth; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhang, Dongliang; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Long; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Ning; Zhou, Yue; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhuravlov, Vadym; Zibell, Andre; Zieminska, Daria; Zimin, Nikolai; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Ziolkowski, Michael; Zitoun, Robert; Živković, Lidija; Zmouchko, Viatcheslav; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zutshi, Vishnu; Zwalinski, Lukasz

    2013-01-01

    This paper presents a summary of beam-induced backgrounds observed in the ATLAS detector and discusses methods to tag and remove background contaminated events in data. Trigger-rate based monitoring of beam-related backgrounds is presented. The correlations of backgrounds with machine conditions, such as residual pressure in the beam-pipe, are discussed. Results from dedicated beam-background simulations are shown, and their qualitative agreement with data is evaluated. Data taken during the passage of unpaired, i.e. non-colliding, proton bunches is used to obtain background-enriched data samples. These are used to identify characteristic features of beam-induced backgrounds, which then are exploited to develop dedicated background tagging tools. These tools, based on observables in the Pixel detector, the muon spectrometer and the calorimeters, are described in detail and their efficiencies are evaluated. Finally an example of an application of these techniques to a monojet analysis is given, which demonstra...

  9. Radiation-Induced Centers in Lead Silicate Glasses Irradiated by Stationary and Pulsed Electron Beams

    Science.gov (United States)

    Zhidkov, I. S.; Zatsepin, A. F.; Konev, S. F.; Cholakh, S. O.

    2015-08-01

    Radiation-induced centers formed in heavy flint glasses irradiated by electron beams are investigated by the methods of optical and EPR spectroscopy. It is revealed that stable and short-living optical absorption centers of close natures are formed under irradiation by fast electrons. A correlation is established between the stable optical absorption bands and the EPR signals interpreted as signals of the (Pb2+)/h+ hole centers. The shortliving color centers are formed due to short-term distortion of the O-Pb bonds, and the stable centers are formed due to the spatial separation, thermalization, and subsequent stabilization of excited electrons and holes in tails of the localized states. Irradiation by electron beams leads to a change in the spectral characteristics of the fundamental absorption edge and, in particular, of the Urbach energy that determines the degree of structural disorder.

  10. Electron-stimulated purification of platinum nanostructures grown via focused electron beam induced deposition

    Directory of Open Access Journals (Sweden)

    Brett B. Lewis

    2015-04-01

    Full Text Available Platinum–carbon nanostructures deposited via electron beam induced deposition from MeCpPt(IVMe3 are purified during a post-deposition electron exposure treatment in a localized oxygen ambient at room temperature. Time-dependent studies demonstrate that the process occurs from the top–down. Electron beam energy and current studies demonstrate that the process is controlled by a confluence of the electron energy loss and oxygen concentration. Furthermore, the experimental results are modeled as a 2nd order reaction which is dependent on both the electron energy loss density and the oxygen concentration. In addition to purification, the post-deposition electron stimulated oxygen purification process enhances the resolution of the EBID process due to the isotropic carbon removal from the as-deposited materials which produces high-fidelity shape retention.

  11. Swift Heavy Ion Beam-induced Recrystallisation of Buried Silicon Nitride Layer (Review Paper

    Directory of Open Access Journals (Sweden)

    T. Som

    2009-07-01

    Full Text Available Studies on MeV heavy ion beam-induced epitaxial crystallisation of a buried silicon nitride layer are reported. Transmission electron micrographs and selected area diffraction patterns have been used to study the recrystallisation of an ion beam-synthesised layer. Complete recrystallisation of the silicon nitride layer having good quality interfaces with the top- and the substrate-Si has been obsorved. Recrystallisation is achieved at significantly lower temperatures of 100 and 200OC for oxygen and silver ions, respectively. The fact that recrystallisation is achieved at the lowest temperature for the oxygen ions is discussed on the basis of energy loss processes.Defence Science Journal, 2009, 59(4, pp.351-355, DOI:http://dx.doi.org/10.14429/dsj.59.1533

  12. Ion-beam-induced nanodots formation from Au/Si thin films on quartz surface

    Energy Technology Data Exchange (ETDEWEB)

    Datta, D.P.; Siva, V.; Singh, A. [School of Physical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Jatni - 752050, Odisha (India); Joshi, S.R. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, Odisha (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Sahoo, P.K., E-mail: pratap.sahoo@niser.ac.in [School of Physical Sciences, National Institute of Science Education and Research (NISER), Bhubaneswar, Jatni - 752050, Odisha (India)

    2016-07-15

    We report the synthesis of Si nanodots on quartz surface using ion irradiation. When a bi-layer of ultrathin Au and Si on quartz surface is irradiated by 500 keV Xe-ion beam, the bi-layer spontaneously transforms into nanodots at a fluence of 5 × 10{sup 14} ions cm{sup −2}. The spatial density and diameter of the nanodots are reduced with increase in applied ion fluence. The nanostructures exhibit photoluminescence in the visible range at room temperature where the intensity and wavelength depends upon ion fluence. The observed evolution seems to be correlated to ion beam mixing induced silicide formation at Au–Si interface.

  13. A Novel Contactless Method for Characterization of Semiconductors: Surface Electron Beam Induced Voltage in Scanning Electron Microscopy

    Institute of Scientific and Technical Information of China (English)

    朱世秋; E.I.RAU; 杨富华; 郑厚植

    2002-01-01

    We present a novel contactless and nondestructive method called the surface electron beam induced voltage (SEBIV) method for characterizing semiconductor materials and devices. The SEBIV method is based on the detection of the surface potential induced by electron beams of scanning electron microscopy (SEM). The core part of the SEBIV detection set-up is a circular metal detector placed above the sample surface. The capacitance between the circular detector and whole surface of the sample is estimated to be about 0.64pf. It is large enough for the detection of the induced surface potential. The irradiation mode of electron beam (e-beam) influences the signal generation. When the e-beam irradiates on the surface of semiconductors continuously, a differential signal is obtained. The real distribution of surface potentials can be obtained when a pulsed e-beam with a fixed frequency is used for irradiation and a lock-in amplifier is employed for detection. The polarity of induced potential depends on the structure of potential barriers and surface states of samples. The contrast of SEBIV images in SEM changes with irradiation time and e-beam intensity.

  14. Ion-beam induced structure modifications in amorphous germanium; Ionenstrahlinduzierte Strukturmodifikationen in amorphem Germanium

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, Tobias

    2012-05-03

    Object of the present thesis was the systematic study of ion-beam induced structure modifications in amorphous germanium (a-Ge) layers due to low- (LEI) and high-energetic (SHI) ion irradiation. The LEI irradiation of crystalline Ge (c-Ge) effects because the dominating nuclear scattering of the ions on the solid-state atoms the formation of a homogeneous a-Ge Layer. Directly on the surface for fluences of two orders of magnitude above the amorphization fluence the formation of stable cavities independently on the irradiation conditions was observed. For the first time for the ion-beam induced cavity formation respectively for the steady expansion of the porous layer forming with growing fluence a linear dependence on the energy {epsilon}{sub n} deposed in nuclear processes was detected. Furthermore the formation of buried cavities was observed, which shows a dependence on the type of ions. While in the c-Ge samples in the range of the high electronic energy deposition no radiation defects, cavities, or plastic deformations were observed, the high electronic energy transfer in the 3.1 {mu}m thick pre-amorphized a-Ge surface layers leads to the formation of randomly distributed cavities. Basing on the linear connection between cavity-induced vertical volume expansion and the fluence determined for different energy transfers for the first time a material-specific threshold value of {epsilon}{sub e}{sup HRF}=(10.5{+-}1.0) kev nm{sup -1} was determined, above which the ion-beam induced cavity formation in a-Ge sets on. The anisotropic plastic deformation of th a-Ge layer superposed at inclined SHI irradiation on the cavity formation was very well described by an equation derived from the viscoelastic Maxwell model, but modified under regardment of the experimental results. The positive deformation yields determined thereby exhibit above a threshold value for the ion-beam induced plastic deformation {epsilon}{sub e}{sup S{sub a}}=(12{+-}2) keV nm{sup -1} for the first

  15. Luminescence techniques: Instrumentation and methods

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.

    1997-01-01

    This paper describes techniques, instruments and methods used in luminescence dating and environmental dosimetry in many laboratories around the world. These techniques are based on two phenomena - thermally stimulated luminescence and optically stimulated luminescence. The most commonly used...... luminescence stimulation and detection techniques are reviewed and information is given on recent developments in instrument design and on the stale of the art in luminescence measurements and analysis. (C) 1998 Elsevier Science Ltd. All rights reserved....

  16. Numerical Simulation on Expansion Process of Ablation Plasma Induced by Intense Pulsed Ion Beam

    Institute of Scientific and Technical Information of China (English)

    TAN Chang; LIU Yue; WANG Xiao-Gang; MA Teng-Cai

    2006-01-01

    We present a one-dimensional time-dependent numerical model for the expansion process of ablation plasmainduced by intense pulsed ion beam(IPIB).The evolutions of density,velocity,temperature,and pressure of theablation plasma of the aluminium target are obtained.The numerical results are well in agreement with therelative experimental data.It is shown that the expansion process of ablation plasma induced by IPIB includesstrongly nonlinear effects and that shock waves appear during the propagation of the ablation plasma.

  17. Spectroscopic Evidence for Exceptional Thermal Contribution to Electron-Beam Induced Fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, Marissa A.; Haynor, Ben; Aloni, Shaul; Ogletree, D. Frank; Wong, H.-S. Philip; Urban, Jeffrey J.; Milliron, Delia J.

    2010-11-16

    While electron beam induced fragmentation (EBIF) has been reported to result in the formation of nanocrystals of various compositions, the physical forces driving this phenomenon are still poorly understood. We report EBIF to be a much more general phenomenon than previously appreciated, operative across a wide variety of metals, semiconductors and insulators. In addition, we leverage the temperature dependent bandgap of several semiconductors to quantify -- using in situ cathodoluminescence spectroscopy -- the thermal contribution to EBIF, and find extreme temperature rises upwards of 1000K.

  18. Monitoring Delamination of Thermal Barrier Coatings by Near-Infrared and Upconversion Luminescence Imaging

    Science.gov (United States)

    Eldridge, J. I.; Martin, R. E.; Singh, Jogender; Wolfe, Doug E.

    2008-01-01

    Previous work has demonstrated that TBC delamination can be monitored by incorporating a thin luminescent sublayer that produces greatly increased luminescence intensity from delaminated regions of the TBC. Initial efforts utilized visible-wavelength luminescence from either europium or erbium doped sublayers. This approach exhibited good sensitivity to delamination of electron-beam physical-vapor-deposited (EB-PVD) TBCs, but limited sensitivity to delamination of the more highly scattering plasma-sprayed TBCs due to stronger optical scattering and to interference by luminescence from rare-earth impurities. These difficulties have now been overcome by new strategies employing near-infrared (NIR) and upconversion luminescence imaging. NIR luminescence at 1550 nm was produced in an erbium plus ytterbium co-doped yttria-stabilized zirconia (YSZ) luminescent sublayer using 980-nm excitation. Compared to visible-wavelength luminescence, these NIR emission and excitation wavelengths are much more weakly scattered by the TBC and therefore show much improved depth-probing capabilities. In addition, two-photon upconversion luminescence excitation at 980 nm wavelength produces luminescence emission at 562 nm with near-zero fluorescence background and exceptional contrast for delamination indication. The ability to detect TBC delamination produced by Rockwell indentation and by furnace cycling is demonstrated for both EB-PVD and plasma-sprayed TBCs. The relative strengths of the NIR and upconversion luminescence methods for monitoring TBC delamination are discussed.

  19. Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL

    CERN Document Server

    Herrera-Martínez, Adonai

    The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

  20. Temperature elevation profile inside the rat brain induced by a laser beam

    Science.gov (United States)

    Ersen, Ali; Abdo, Ammar; Sahin, Mesut

    2014-01-01

    The thermal effect may be a desired outcome or a concerning side effect in laser-tissue interactions. Research in this area is particularly motivated by recent advances in laser applications in diagnosis and treatment of neurological disorders. Temperature as a side effect also limits the maximum power of optical transfer and harvesting of energy in implantable neural prostheses. The main objective was to investigate the thermal effect of a near-infrared laser beam directly aimed at the brain cortex. A small, custom-made thermal probe was inserted into the rat brain to make direct measurements of temperature elevations induced by a free-air circular laser beam. The time dependence and the spatial distribution of the temperature increases were studied and the maximum allowable optical power was determined to be 2.27 W/cm2 for a corresponding temperature increase of 0.5°C near the cortical surface. The results can be extrapolated for other temperature elevations, where the margin to reach potentially damaging temperatures is more relaxed, by taking advantage of linearity. It is concluded that the thermal effect depends on several factors such as the thermal properties of the neural tissue and of its surrounding structures, the optical properties of the particular neural tissue, and the laser beam size and shape. Because so many parameters play a role, the thermal effect should be investigated for each specific application separately using realistic in vivo models.

  1. Coded-aperture imaging using photo-induced reconfigurable aperture arrays for mapping terahertz beams

    CERN Document Server

    Kannegulla, Akash; Rahman, Syed; Fay, Patrick; Xing, Huili Grace; Cheng, Li-Jing; Liu, Lei

    2013-01-01

    We report terahertz coded-aperture imaging using photo-induced reconfigurable aperture arrays on a silicon wafer. The coded aperture was implemented using programmable illumination from a commercially available digital light processing projector. At 590 GHz, each of the array element apertures can be optically turned on and off with a modulation depth of 20 dB and a modulation rate of ~1.3 KHz. Prototype demonstrations of 4 by 4 coded-aperture imaging using Hadamard coding have been performed and this technique has been successfully applied to mapping THz beams by using a 6 by 6 aperture array at 590 GHz. The imaging results agree closely with theoretical calculations based on Gaussian beam transformation, demonstrating that this technique is promising for realizing real-time and low-cost terahertz cameras for many applications. The reported approach provides a simple but powerful means to visualize THz beams, which is highly desired in quasi-optical system alignment, quantum-cascade laser design and characte...

  2. The controlled fabrication of nanopores by focused electron-beam-induced etching

    Science.gov (United States)

    Yemini, M.; Hadad, B.; Liebes, Y.; Goldner, A.; Ashkenasy, N.

    2009-06-01

    The fabrication of nanometric holes within thin silicon-based membranes is of great importance for various nanotechnology applications. The preparation of such holes with accurate control over their size and shape is, thus, gaining a lot of interest. In this work we demonstrate the use of a focused electron-beam-induced etching (FEBIE) process as a promising tool for the fabrication of such nanopores in silicon nitride membranes and study the process parameters. The reduction of silicon nitride by the electron beam followed by chemical etching of the residual elemental silicon results in a linear dependence of pore diameter on electron beam exposure time, enabling accurate control of nanopore size in the range of 17-200 nm in diameter. An optimal pressure of 5.3 × 10-6 Torr for the production of smaller pores with faster process rates, as a result of mass transport effects, was found. The pore formation process is also shown to be dependent on the details of the pulsed process cycle, which control the rate of the pore extension, and its minimal and maximal size. Our results suggest that the FEBIE process may play a key role in the fabrication of nanopores for future devices both in sensing and nano-electronics applications.

  3. The controlled fabrication of nanopores by focused electron-beam-induced etching

    Energy Technology Data Exchange (ETDEWEB)

    Yemini, M; Ashkenasy, N [Department of Materials Engineering, Ben-Gurion University of the Negev, PO Box 653 Beer-Sheva (Israel); Hadad, B; Goldner, A [The Weiss Family Laboratory for Nano-Scale Systems, Ben-Gurion University of the Negev, PO Box 653 Beer-Sheva (Israel); Liebes, Y [Department of Biotechnology Engineering, Ben-Gurion University of the Negev, PO Box 653 Beer-Sheva (Israel)], E-mail: nurita@bgu.ac.il

    2009-06-17

    The fabrication of nanometric holes within thin silicon-based membranes is of great importance for various nanotechnology applications. The preparation of such holes with accurate control over their size and shape is, thus, gaining a lot of interest. In this work we demonstrate the use of a focused electron-beam-induced etching (FEBIE) process as a promising tool for the fabrication of such nanopores in silicon nitride membranes and study the process parameters. The reduction of silicon nitride by the electron beam followed by chemical etching of the residual elemental silicon results in a linear dependence of pore diameter on electron beam exposure time, enabling accurate control of nanopore size in the range of 17-200 nm in diameter. An optimal pressure of 5.3 x 10{sup -6} Torr for the production of smaller pores with faster process rates, as a result of mass transport effects, was found. The pore formation process is also shown to be dependent on the details of the pulsed process cycle, which control the rate of the pore extension, and its minimal and maximal size. Our results suggest that the FEBIE process may play a key role in the fabrication of nanopores for future devices both in sensing and nano-electronics applications.

  4. Reaction mechanisms in collisions induced by $^{8}$B beam close to the barrier

    CERN Multimedia

    The aim of the proposed experiment is to investigate the reaction dynamics of proton-halo induced collisions at energies around the Coulomb barrier where coupling to continuum effects are expected to be important. We propose to measure the $^{8}$B + $^{64}$Zn elastic scattering angular distribution together with the measurement, for the first time, of p - $^{7}$Be coincidences coming from transfer and/or break-up of $^{8}$B. The latter will allow a better understanding of the relative contribution of elastic $\\textit{vs}$ non-elastic break-up in reactions induced by extremely weakly-bound nuclei. We believe that with the availability of the post accelerated $^{8}$B beam at REX-ISOLDE we will be able to collect for the first time high quality data for the study of such an important topic.

  5. Microbeam Studies of Diffusion Time Resolved Ion Beam Induced Charge Collection from Stripe-Like Junctions

    Energy Technology Data Exchange (ETDEWEB)

    GUO,B.N.; BOUANANI,M.E.; RENFROW,S.N.; WALSH,DAVID S.; DOYLE,BARNEY L.; ATON,T.J.; SMITH,E.B.; BAUMANN,R.C.; DUGGAN,J.L.; MCDANIEL,F.D.

    2000-06-14

    To design more radiation tolerant Integrated Circuits (ICs), it is essential to create and test accurate models of ionizing radiation induced charge collection dynamics within microcircuits. A new technique, Diffusion Time Resolved Ion Beam Induced Charge Collection (DTRIBICC), is proposed to measure the average arrival time of the diffused charge at the junction. Specially designed stripe-like junctions were experimentally studied using a 12 MeV carbon microbeam with a spot size of 1 {micro}m. The relative arrival time of ion-generated charge is measured along with the charge collection using a multiple parameter data acquisition system. The results show the importance of the diffused charge collection by junctions, which is especially significant in accounting for Multiple Bit Upset (MBUs) in digital devices.

  6. Swift heavy ion induced structural and luminescence characterization of Y₂O₃:Eu³⁺ phosphor: a comparative study.

    Science.gov (United States)

    Som, S; Sharma, S K; Lochab, S P

    2014-08-01

    We report a comparative study on structural and thermoluminescence modifications of Y2O3:Eu(3+) phosphor induced by 150 MeV Ni(7+), 120 MeV Ag(9+) and 110 MeV Au(8+) swift heavy ions (SHI) in the fluence range 1 × 10(11) to 1 × 10(13) ions/cm(2). X-Ray diffraction and transition electron microscopy studies confirm the loss of crystallinity of the phosphors after ion irradiation, which is greater in the case of Au ion irradiation. Structural refinement using the Rietveld method yields the various structural parameters of ion-irradiated phosphors. Thermoluminescence glow curves of ion-irradiated phosphors show a small shift in the position of the peaks, along with an increase in intensity with ion fluence. Stopping range of ions in Matter (SRIM) calculations were performed to correlate the change in thermoluminescence properties of various ion-irradiated phosphors. It shows that the defects created by 110 MeV Au(8+) ions are greater in number. Trapping parameters of ion-irradiated phosphors were calculated from thermoluminescence data using various glow curve analysis methods.

  7. Beam-induced radiation in the compact muon solenoid tracker at the Large Hadron Collider

    Indian Academy of Sciences (India)

    A P Singh; P C Bhat; N V Mokhov; S Beri

    2010-05-01

    The intense radiation environment at the Large Hadron Collider, CERN at a design energy of $\\sqrt{s} = 14$ TeV and a luminosity of 1034 cm−2S−1 poses unprecedented challenges for safe operation and performance quality of the silicon tracker detectors in the CMS and ATLAS experiments. The silicon trackers are crucial for the physics at the LHC experiments, and the inner layers, being situated only a few centimeters from the interaction point, are most vulnerable to beam-induced radiation. We have recently carried out extensive Monte Carlo simulation studies using MARS program to estimate particle fluxes and radiation dose in the CMS silicon pixel and strip trackers from proton–proton collisions at $\\sqrt{s} = 14$ TeV and from machine-induced background such as beam–gas interactions and beam halo. We will present results on radiation dose, particle fluxes and spectra from these studies and discuss implications for radiation damage and performance of the CMS silicon tracker detectors.

  8. Electron beam induced synthesis of uranium dioxide nanoparticles: Effect of solvent composition

    Science.gov (United States)

    Rath, M. C.; Keny, S. J.; Naik, D. B.

    2016-09-01

    The effect of various compositions of solvents was investigated on the electron beam induced synthesis of uranium dioxide, UO2 nanoparticles. The synthesis was carried out at different pHs from 2 to 7 in the aqueous solutions containing 10 mM uranyl nitrate and 10% 2-propanol. The formation of UO2 nanoparticles was found to occur only in the pH range from 2.5 to 3.7. Experiments were also carried out in the aqueous solutions containing various other alcohols (10% v/v) such as methanol, ethanol, 1-propanol, 1-butanol or tert-butanol as well as in solutions containing 10 mM sodium formate at pH 3.4. The formation of UO2 nanoparticles in the aqueous solutions was found to occur only in the presence of ethanol, 1-propanol, 2-propanol or 1-butanol. It is therefore confirmed that the electron beam induced synthesis of UO2 nanoparticles strongly depends on the solvent compositions as well as the pH of the medium.

  9. Direct-write deposition and focused-electron-beam-induced purification of gold nanostructures.

    Science.gov (United States)

    Belić, Domagoj; Shawrav, Mostafa M; Gavagnin, Marco; Stöger-Pollach, Michael; Wanzenboeck, Heinz D; Bertagnolli, Emmerich

    2015-02-04

    Three-dimensional gold (Au) nanostructures offer promise in nanoplasmonics, biomedical applications, electrochemical sensing and as contacts for carbon-based electronics. Direct-write techniques such as focused-electron-beam-induced deposition (FEBID) can provide such precisely patterned nanostructures. Unfortunately, FEBID Au traditionally suffers from a high nonmetallic content and cannot meet the purity requirements for these applications. Here we report exceptionally pure pristine FEBID Au nanostructures comprising submicrometer-large monocrystalline Au sections. On the basis of high-resolution transmission electron microscopy results and Monte Carlo simulations of electron trajectories in the deposited nanostructures, we propose a curing mechanism that elucidates the observed phenomena. The in situ focused-electron-beam-induced curing mechanism was supported by postdeposition ex situ curing and, in combination with oxygen plasma cleaning, is utilized as a straightforward purification method for planar FEBID structures. This work paves the way for the application of FEBID Au nanostructures in a new generation of biosensors and plasmonic nanodevices.

  10. Direct-Write Fabrication of Cellulose Nano-Structures via Focused Electron Beam Induced Nanosynthesis

    Science.gov (United States)

    Ganner, Thomas; Sattelkow, Jürgen; Rumpf, Bernhard; Eibinger, Manuel; Reishofer, David; Winkler, Robert; Nidetzky, Bernd; Spirk, Stefan; Plank, Harald

    2016-09-01

    In many areas of science and technology, patterned films and surfaces play a key role in engineering and development of advanced materials. Here, we introduce a new generic technique for the fabrication of polysaccharide nano-structures via focused electron beam induced conversion (FEBIC). For the proof of principle, organosoluble trimethylsilyl-cellulose (TMSC) thin films have been deposited by spin coating on SiO2 / Si and exposed to a nano-sized electron beam. It turns out that in the exposed areas an electron induced desilylation reaction takes place converting soluble TMSC to rather insoluble cellulose. After removal of the unexposed TMSC areas, structured cellulose patterns remain on the surface with FWHM line widths down to 70 nm. Systematic FEBIC parameter sweeps reveal a generally electron dose dependent behavior with three working regimes: incomplete conversion, ideal doses and over exposure. Direct (FT-IR) and indirect chemical analyses (enzymatic degradation) confirmed the cellulosic character of ideally converted areas. These investigations are complemented by a theoretical model which suggests a two-step reaction process by means of TMSC → cellulose and cellulose → non-cellulose material conversion in excellent agreement with experimental data. The extracted, individual reaction rates allowed the derivation of design rules for FEBIC parameters towards highest conversion efficiencies and highest lateral resolution.

  11. In situ growth optimization in focused electron-beam induced deposition

    Directory of Open Access Journals (Sweden)

    Paul M. Weirich

    2013-12-01

    Full Text Available We present the application of an evolutionary genetic algorithm for the in situ optimization of nanostructures that are prepared by focused electron-beam-induced deposition (FEBID. It allows us to tune the properties of the deposits towards the highest conductivity by using the time gradient of the measured in situ rate of change of conductance as the fitness parameter for the algorithm. The effectiveness of the procedure is presented for the precursor W(CO6 as well as for post-treatment of Pt–C deposits, which were obtained by the dissociation of MeCpPt(Me3. For W(CO6-based structures an increase of conductivity by one order of magnitude can be achieved, whereas the effect for MeCpPt(Me3 is largely suppressed. The presented technique can be applied to all beam-induced deposition processes and has great potential for a further optimization or tuning of parameters for nanostructures that are prepared by FEBID or related techniques.

  12. Laser marking on soda-lime glass by laser-induced backside wet etching with two-beam interference

    Science.gov (United States)

    Nakazumi, Tomoka; Sato, Tadatake; Narazaki, Aiko; Niino, Hiroyuki

    2016-09-01

    For crack-free marking of glass materials, a beam-scanning laser-induced backside wet etching (LIBWE) process by a beam spot with a fine periodic structure was examined. The fine periodic structure was produced within a beam spot by means of a Mach-Zehnder interferometer incorporated to the optical setup for the beam-scanning LIBWE. A fine structure with a period of 9 µm was observed within the microstructures with a diameter of ca. 40 µm fabricated by a laser shot under double-beam irradiation, and they could be homogeneously fabricated within an area of 800  ×  800 µm. The area filled with the microstructures, including fine periodic structures, could be observed in high contrast under a diffuse, on-axis illumination that was used in commercial QR code readers.

  13. Beam Energy Scaling of Ion-Induced Electron Yield from K+ Ions Impact on Stainless Steel Surfaces

    CERN Document Server

    Kireeff-Covo, Michel; Barnard, John J; Bieniosek, Frank; Celata, C M; Cohen, Ronald; Friedman, Alex; Grote, D P; Kwan, Joe W; Lund, Steven M; Molvik, Arthur; Seidl, Peter; Vay, Jean-Luc; Vujic, Jasmina L; Westenskow, Glen

    2005-01-01

    The cost of accelerators for heavy-ion inertial fusion energy (HIF) can be reduced by using the smallest possible clearance between the beam and the wall from the beamline. This increases beam loss to the walls, generating ion-induced electrons that could be trapped by beam space charge potential into an "electron cloud," which can cause degradation or loss of the ion beam. In order to understand the physical mechanism of production of ion-induced electrons we have measured impact of K+ ions with energies up to 400 KeV on stainless steel surfaces near grazing incidence, using the ion source test stand (STS-500) at LLNL. The electron yield will be discussed and compared with experimental measurements from 1 MeV K+ ions in the High-Current Experiment at LBNL.*

  14. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess)

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Gil-Hah, E-mail: khkim@chungbuk.ac.kr [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2012-01-15

    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii. - Highlights: > Electron beam irradiation inhibited normal development of the leaf miner. > Electron beam irradiation inhibited normal reproduction of the leaf miner. > Electron beam irradiation increased levels of DNA damage. > Electron beam irradiation induced p53 stability.

  15. High aspect ratio AFM Probe processing by helium-ion-beam induced deposition.

    Science.gov (United States)

    Onishi, Keiko; Guo, Hongxuan; Nagano, Syoko; Fujita, Daisuke

    2014-11-01

    A Scanning Helium Ion Microscope (SHIM) is a high resolution surface observation instrument similar to a Scanning Electron Microscope (SEM) since both instruments employ finely focused particle beams of ions or electrons [1]. The apparent difference is that SHIMs can be used not only for a sub-nanometer scale resolution microscopic research, but also for the applications of very fine fabrication and direct lithography of surfaces at the nanoscale dimensions. On the other hand, atomic force microscope (AFM) is another type of high resolution microscopy which can measure a three-dimensional surface morphology by tracing a fine probe with a sharp tip apex on a specimen's surface.In order to measure highly uneven and concavo-convex surfaces by AFM, the probe of a high aspect ratio with a sharp tip is much more necessary than the probe of a general quadrangular pyramid shape. In this paper we report the manufacture of the probe tip of the high aspect ratio by ion-beam induced gas deposition using a nanoscale helium ion beam of SHIM.Gas of platinum organic compound was injected into the sample surface neighborhood in the vacuum chamber of SHIM. The decomposition of the gas and the precipitation of the involved metal brought up a platinum nano-object in a pillar shape on the normal commercial AFM probe tip. A SHIM system (Carl Zeiss, Orion Plus) equipped with the gas injection system (OmniProbe, OmniGIS) was used for the research. While the vacuum being kept to work, we injected platinum organic compound ((CH3)3(CH3C5H4)Pt) into the sample neighborhood and irradiated the helium ion beam with the shape of a point on the apex of the AFM probe tip. It is found that we can control the length of the Pt nano-pillar by irradiation time of the helium ion beam. The AFM probe which brought up a Pt nano-pillar is shown in Figure 1. It is revealed that a high-aspect-ratio Pt nano-pillar of ∼40nm diameter and up to ∼2000 nm length can be grown. In addition, for possible heating

  16. Interpreting effects of structure variations induced by temperature and pressure on luminescence spectra of platinum(II) bis(dithiocarbamate) compounds.

    Science.gov (United States)

    Poirier, Stéphanie; Roberts, Ryan J; Le, Debbie; Leznoff, Daniel B; Reber, Christian

    2015-04-20

    Luminescence spectra of two square-planar dithiocarbamate complexes of platinum(II) with different steric bulk, platinum(II) bis(dimethyldithiocarbamate) (Pt(MeDTC)2) and platinum(II) bis(di(o-pyridyl)dithiocarbamate) (Pt(dopDTC)2), are presented at variable temperature and pressure. The spectra show broad d-d luminescence transitions with maxima at approximately 13500 cm(-1) (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt(dopDTC)2. Luminescence maxima of Pt(MeDTC)2 shift to higher energy as temperature increases by +320 cm(-1) for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm(-1) on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt(dopDTC)2 shift in the opposite direction by -460 cm(-1) for a temperature increase by 200 K. The bandwidth of approximately 2900 cm(-1) does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 ± 3 and +11 ± 1 cm(-1)/kbar, for Pt(MeDTC)2 and Pt(dopDTC)2, respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt(MeDTC)2.

  17. Polarization-dependent single-beam laser-induced grating-like effects on titanium films

    Energy Technology Data Exchange (ETDEWEB)

    Camacho-Lopez, Santiago [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico)], E-mail: camachol@cicese.mx; Evans, Rodger [Departamento de Optica, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Km 107 Carretera Tijuana-Ensenada, Ensenada, Baja California 22860 (Mexico); Escobar-Alarcon, Luis [Departamento de Fisica, Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, Mexico DF 11801 (Mexico); Camacho-Lopez, Miguel A. [Facultad de Medicina, Universidad Autonoma del Estado de Mexico, Paseo Tollocan s/n, esq. Jesus Carranza, Toluca, Estado de Mexico 50120 (Mexico); Camacho-Lopez, Marco A. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Tollocan s/n, esq. Paseo Colon, Toluca, Estado de Mexico, 50110 (Mexico)

    2008-12-30

    In this paper we present results on polarization-dependent laser-induced effects on titanium (Ti) thin films. We irradiated the titanium films, in ambient air, using a nanosecond Nd:YAG laser (532 nm, 9 ns pulse duration, 10 Hz). Using a series of pulses of fluence well below the ablation threshold, it was possible to form grating-like structures, whose grooves run parallel to the linear polarization of the incident beam. No grating-like structures were obtained when circularly polarized light was used. Our results revealed the remarkable formation of tiny (100 nm and even smaller diameter) craters, which self-arrange quasi-periodically along the ridges (never on the valleys) of the grating-like structure. Optical and scanning electron microscopy were used to study the laser-induced changes on the surface of the titanium films. Micro-Raman spectroscopy was used to analyze the irradiated areas on the titanium films. The Raman analysis demonstrated that the grooves in the grating-like structure, build up from the laser-induced oxidation of titanium. This is the first time, to the best of our knowledge, that periodic surface structures are reported to be induced below the ablation threshold regime, with the grooves made of crystalline metal oxide, in this case TiO{sub 2} in the well-known Rutile phase. The laser irradiated areas on the film acquired selective (upon recording polarization) holographic reflectance.

  18. Purity and resistivity improvements for electron-beam-induced deposition of Pt

    Energy Technology Data Exchange (ETDEWEB)

    Mulders, J.J.L. [FEI Company, Eindhoven (Netherlands)

    2014-12-15

    Electron-beam-induced deposition (EBID) of platinum is used by many researchers. Its main application is the formation of a protective layer and the ''welding material'' for making a TEM lamella with a focused ion beam thinning process. For this application, the actual composition of the deposition is less relevant, and in practice, both the mechanical strength and the conductivity are sufficient. Another important application is the creation of an electrical connection to nanoscale structures such as nano-wires and graphene. To serve as an electrical contact, the resistivity of the Pt deposited structure has to be sufficiently low. Using the commonly used precursor MeCpPtMe{sub 3} for deposition, the resistivity as created by the basic process is 10{sup +5}-10{sup +6} higher than the value for bulk Pt, which is 10.6 μΩ cm. The reason for this is the high abundance of carbon in the deposition. To improve the deposition process, much attention has been given by the research community to parameter optimization, to ex situ or in situ removal of carbon by anneal steps, to prevention of carbon deposition by use of a carbon-free precursor, to electron beam irradiation under a high flux of oxygen and to the combination with other techniques such as atomic layer deposition (ALD). In the latter technique, the EBID structures are used as a 1-nm-thick seed layer only, while the ALD is used to selectively add pure Pt. These techniques have resulted in a low resistivity, today approaching the 10-150 μΩ cm, while the size and shape of the structure are preserved. Therefore, now, the technique is ready for application in the field of contacting nano-wires. (orig.)

  19. Focused-electron-beam-induced processing (FEBIP) for emerging applications in carbon nanoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, Andrei G. [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA (United States); Georgia Institute of Technology, Parker H. Petit Institute for Bioengineering and Bioscience, Atlanta, GA (United States); Kim, Songkil; Henry, Mathias [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA (United States); Kulkarni, Dhaval; Tsukruk, Vladimir V. [Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta, GA (United States)

    2014-07-27

    Focused-electron-beam-induced processing (FEBIP), a resist-free additive nanomanufacturing technique, is an actively researched method for ''direct-write'' processing of a wide range of structural and functional nanomaterials, with high degree of spatial and time-domain control. This article attempts to critically assess the FEBIP capabilities and unique value proposition in the context of processing of electronics materials, with a particular emphasis on emerging carbon (i.e., based on graphene and carbon nanotubes) devices and interconnect structures. One of the major hurdles in advancing the carbon-based electronic materials and device fabrication is a disjoint nature of various processing steps involved in making a functional device from the precursor graphene/CNT materials. Not only this multi-step sequence severely limits the throughput and increases the cost, but also dramatically reduces the processing reproducibility and negatively impacts the quality because of possible between-the-step contamination, especially for impurity-susceptible materials such as graphene. The FEBIP provides a unique opportunity to address many challenges of carbon nanoelectronics, especially when it is employed as part of an integrated processing environment based on multiple ''beams'' of energetic particles, including electrons, photons, and molecules. This avenue is promising from the applications' prospective, as such a multi-functional (electron/photon/molecule beam) enables one to define shapes (patterning), form structures (deposition/etching), and modify (cleaning/doping/annealing) properties with locally resolved control on nanoscale using the same tool without ever changing the processing environment. It thus will have a direct positive impact on enhancing functionality, improving quality and reducing fabrication costs for electronic devices, based on both conventional CMOS and emerging carbon (CNT/graphene) materials. (orig.)

  20. Localized surface grafting reactions on carbon nanofibers induced by gamma and e-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Evora, M.C., E-mail: cecilia@ieav.cta.br [Institute for Advanced Studies-IEAV/DCTA, Av. Cel Jose Alberto Albano do Amarante, 1-Putim, 12228-001 São Jose dos Campos, SP (Brazil); Araujo, J.R., E-mail: jraraujo@inmetro.gov.br [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Ferreira, E.H.M. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil); Strohmeier, B.R. [Thermo Fisher Scientific, 5225 Verona Road, Madison, WI 53711 (United States); Silva, L.G.A., E-mail: lgasilva@ipen.br [Institute for Nuclear and Energy Research- IPEN, Av. Prof lineu Prestes, 2242- Cidade Universitaria, 05508-000 SP (Brazil); Achete, C.A. [Instituto Nacional de Metrologia, Qualidade e Tecnologia, Av. Nossa Sra. das Graças, 50, 25250-020 Duque de Caxias, RJ (Brazil)

    2015-04-30

    Graphical abstract: - Highlights: • Methodology for the functionalization of carbon nanofibers was investigated. • Two radiation sources were used to promote grafting reactions: gamma and electron beam. • We report the optimum inhibitor concentration to achieve the functionalization. • Surface of carbon nanofibers showed an increase of oxygen content after irradiation. • The radiation-induced graphitization did not damage the overall sp{sup 2} structure. - Abstract: Electron beam and gamma-ray irradiation have potential application to modify the carbon fiber nanostructures in order to produce useful defects in the graphitic structure and create reactive sites. In this study, the methodology to functionalize carbon nanofiber (CNF), via a radiation process and using acrylic acid as a source of oxygen functional groups, was investigated. The samples were submitted to a direct grafting radiation process with electron beam and gamma-ray source. Several parameters were changed such as: acrylic acid concentration, radiation dose and percentage of inhibitor necessary to achieve functionalization, with higher percentage of oxygen functional groups on CNF surface, and better dispersion. The better results achieved were when mixing CNF in a solution of acrylic acid with 6% of inhibitor (FeSO{sub 4}·7H{sub 2}O) and irradiated at 100 kGy. The samples were characterized by X-ray photoelectron spectroscopy and the surface composition (atomic%) showed a significant increase of oxygen content for the samples after irradiation. Also, the dispersion of the functionalized CNF in water was stable during months which may be a good indication that the functionalization process of CNF via ionizing radiation was successful.

  1. Quantitative luminescence imaging system

    Science.gov (United States)

    Batishko, C. R.; Stahl, K. A.; Fecht, B. A.

    The goal of the Measurement of Chemiluminescence project is to develop and deliver a suite of imaging radiometric instruments for measuring spatial distributions of chemiluminescence. Envisioned deliverables include instruments working at the microscopic, macroscopic, and life-sized scales. Both laboratory and field portable instruments are envisioned. The project also includes development of phantoms as enclosures for the diazoluminomelanin (DALM) chemiluminescent chemistry. A suite of either phantoms in a variety of typical poses, or phantoms that could be adjusted to a variety of poses, is envisioned. These are to include small mammals (rats), mid-sized mammals (monkeys), and human body parts. A complete human phantom that can be posed is a long-term goal of the development. Taken together, the chemistry and instrumentation provide a means for imaging rf dosimetry based on chemiluminescence induced by the heat resulting from rf energy absorption. The first delivered instrument, the Quantitative Luminescence Imaging System (QLIS), resulted in a patent, and an R&D Magazine 1991 R&D 100 award, recognizing it as one of the 100 most significant technological developments of 1991. The current status of the project is that three systems have been delivered, several related studies have been conducted, two preliminary human hand phantoms have been delivered, system upgrades have been implemented, and calibrations have been maintained. Current development includes sensitivity improvements to the microscope-based system; extension of the large-scale (potentially life-sized targets) system to field portable applications; extension of the 2-D large-scale system to 3-D measurement; imminent delivery of a more refined human hand phantom and a rat phantom; rf, thermal and imaging subsystem integration; and continued calibration and upgrade support.

  2. Wakefield-Induced Ionization injection in beam-driven plasma accelerators

    CERN Document Server

    de la Ossa, A Martinez; Streeter, M J V; Osterhoff, J

    2015-01-01

    We present a detailed analysis of the features and capabilities of Wakefield-Induced Ionization (WII) injection in the blowout regime of beam driven plasma accelerators. This mechanism exploits the electric wakefields to ionize electrons from a dopant gas and trap them in a well-defined region of the accelerating and focusing wake phase, leading to the formation of high-quality witness-bunches. The electron-beam drivers must feature high-peak currents ($I_b^0\\gtrsim 8.5~\\mathrm{kA}$) and a duration comparable to the plasma wavelength to excite plasma waves in the blowout regime and enable WII injection. In this regime, the disparity of the magnitude of the electric field in the driver region and the electric field in the rear of the ion cavity allows for the selective ionization and subsequent trapping from a narrow phase interval. The witness bunches generated in this manner feature a short duration and small values of the normalized transverse emittance ($k_p\\sigma_z \\sim k_p\\epsilon_n \\sim 0.1$). In additi...

  3. Single-crystal nanowires grown via electron-beam-induced deposition

    Science.gov (United States)

    Klein, K. L.; Randolph, S. J.; Fowlkes, J. D.; Allard, L. F.; Meyer, H. M., III; Simpson, M. L.; Rack, P. D.

    2008-08-01

    Electron-beam-induced deposition (EBID) is a useful technique for direct-writing of three-dimensional dielectric, semiconductor, and metallic materials with nanoscale precision and resolution. The EBID process, however, has been limited in many cases because precursor byproducts (typically from organic precursors like W(CO)6) are incorporated into the deposited material resulting in contaminated and amorphous structures. In this work, we have investigated the structure and composition of EBID tungsten nanostructures as-deposited from a tungsten hexafluoride (WF6) precursor. High resolution transmission electron microscopy, electron diffraction and electron spectroscopy were employed to determine the effects that the electron beam scanning conditions have on the deposit characteristics. The results show that slow, one-dimensional lateral scanning produces textured β-tungsten nanowire cores surrounded by an oxide secondary layer, while stationary vertical growth leads to single-crystal [100]-oriented W3O nanowires. Furthermore we correlate how the growth kinetics affect the resultant nanowire structure and composition.

  4. Single-crystal nanowires grown via electron-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Klein, K L; Randolph, S J; Simpson, M L; Rack, P D [Materials Science and Engineering Department, University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996 (United States); Fowlkes, J D [Center for Nanophase Materials Sciences Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831 (United States); Allard, L F; III, H M Meyer [Materials Science and Technology Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831 (United States)], E-mail: prack@utk.edu

    2008-08-27

    Electron-beam-induced deposition (EBID) is a useful technique for direct-writing of three-dimensional dielectric, semiconductor, and metallic materials with nanoscale precision and resolution. The EBID process, however, has been limited in many cases because precursor byproducts (typically from organic precursors like W(CO){sub 6}) are incorporated into the deposited material resulting in contaminated and amorphous structures. In this work, we have investigated the structure and composition of EBID tungsten nanostructures as-deposited from a tungsten hexafluoride (WF{sub 6}) precursor. High resolution transmission electron microscopy, electron diffraction and electron spectroscopy were employed to determine the effects that the electron beam scanning conditions have on the deposit characteristics. The results show that slow, one-dimensional lateral scanning produces textured {beta}-tungsten nanowire cores surrounded by an oxide secondary layer, while stationary vertical growth leads to single-crystal [100]-oriented W{sub 3}O nanowires. Furthermore we correlate how the growth kinetics affect the resultant nanowire structure and composition.

  5. Cobalt-based magnetic nanostructures grown by focused-electron-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Begun, Evgeniya; Schwenk, Johannes; Porrati, Fabrizio; Huth, Michael [Physikalisches Institut, Goethe-Universitaet, D-60438 Frankfurt am Main (Germany)

    2011-07-01

    The fabrication of magnetic nanostructures by means of the direct-writing technique focused-electron-beam-induced deposition (FEBID) is an alternative to more conventional lithographic methods. We have grown magnetic cobalt structures by FEBID using the precursor dicobaltoctacarbonyl Co{sub 2}(CO){sub 8}. The obtained structures have a large metal content of about 85 at.% as compared to other metal-based deposits grown by the same technique, such as tungsten-based structures with 34 at.% maximum tungsten content and platin-based structures with about 24 at.% maximum platin content. We present a growth strategy for cobalt structures with tunable metal content. In particular, we show the influence of different combinations of electron-beam energy and current, the dwell time and the refresh time on the deposit composition, which was determined by energy-dispersive X-ray spectroscopy (EDX) at 5 keV. First results of magnetotransport measurements on these cobalt-based structures are presented.

  6. Fe:O:C grown by focused-electron-beam-induced deposition: magnetic and electric properties

    Energy Technology Data Exchange (ETDEWEB)

    Lavrijsen, R; Schoenaker, F J; Ellis, T H; Barcones, B; Kohlhepp, J T; Swagten, H J M; Koopmans, B [Department of Applied Physics, Center for NanoMaterials and COBRA Research Institute, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Cordoba, R; Ibarra, M R [Instituto de Nanociencia de Aragon, Universidad de Zaragoza, E-50009 Zaragoza (Spain); De Teresa, J M; Magen, C [Departamento de Fisica de la Materia Condensada, Universidad de Zaragoza, E-50009 Zaragoza (Spain); Trompenaars, P; Mulders, J J L, E-mail: r.lavrijsen@tue.nl, E-mail: deteresa@unizar.es [FEI Electron Optics, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands)

    2011-01-14

    We systematically study the effect of oxygen content on the magneto-transport and microstructure of Fe:O:C nanowires deposited by focused-electron-beam-induced (FEBID) deposition. The Fe/O ratio can be varied with an Fe content varying between {approx} 50 and 80 at.% with overall low C content ({approx}16 {+-} 3 at.%) by adding H{sub 2}O during the deposition while keeping the beam parameters constant as measured by energy dispersive x-ray (EDX) spectroscopy. The room-temperature magnetic properties for deposits with an Fe content of 66-71 at.% are investigated using the magneto-optical Kerr effect (MOKE) and electric magneto-transport measurements. The nanostructure of the deposits is investigated through cross-sectional high-resolution transmission electron microscopy (HRTEM) imaging, allowing us to link the observed magneto-resistance and resistivity to the transport mechanism in the deposits. These results demonstrate that functional magnetic nanostructures can be created, paving the way for new magnetic or even spintronics devices.

  7. Evidence against a universal electron-beam-induced virtual temperature in graphene

    Science.gov (United States)

    Börner, Pia; Kaiser, Ute; Lehtinen, Ossi

    2016-04-01

    The continuous electron bombardment of a sample during transmission electron microscopy (TEM) drives atomic-scale transformations. In earlier studies the transformations appeared to proceed as if the sample was held at an elevated temperature, and, indeed, the hypothesis of an electron-beam-induced virtual temperature has gained traction in the scientific community. However, the sample is not significantly heated by the electron beam, meaning the processes are not activated by thermal vibrations. Instead, individual collisions between the electrons and the target atoms, and/or excitations of the electronic system, lead to the observed transformations. It is not a priori clear what virtual temperature can be assigned to the conditions under the electron irradiation, or even if such a temperature can be defined at all. Here, we attempt to measure the virtual temperature, specific to this system, by comparing the relative population of the three different divacancy defect states in single-layer graphene to the Boltzmann distribution using calculated energy levels of the defect states. The experiment is conducted using aberration-corrected high-resolution TEM at an acceleration voltage of 80 kV. Atomistic simulations are used to learn about the energetics of the defects. We find that the measured populations cannot be fitted to the Boltzmann distribution, and consequently no universal virtual temperature can be assigned to the system.

  8. Various categories of defects after surface alloying induced by high current pulsed electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Dian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Tang, Guangze, E-mail: oaktang@hit.edu.cn [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Xinxin [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Gu, Le [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Mingren [School of Material Science & Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Liqin [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-10-01

    Highlights: • Four kinds of defects are found during surface alloying by high current electron beam. • Exploring the mechanism how these defects appear after irradiation. • Increasing pulsing cycles will help to get good surface quality. • Choosing proper energy density will increase surface quality. - Abstract: High current pulsed electron beam (HCPEB) is an attractive advanced materials processing method which could highly increase the mechanical properties and corrosion resistance. However, how to eliminate different kinds of defects during irradiation by HCPEB especially in condition of adding new elements is a challenging task. In the present research, the titanium and TaNb-TiW composite films was deposited on the carburizing steel (SAE9310 steel) by DC magnetron sputtering before irradiation. The process of surface alloying was induced by HCPEB with pulse duration of 2.5 μs and energy density ranging from 3 to 9 J/cm{sup 2}. Investigation of the microstructure indicated that there were several forms of defects after irradiation, such as surface unwetting, surface eruption, micro-cracks and layering. How the defects formed was explained by the results of electron microscopy and energy dispersive spectroscopy. The results also revealed that proper energy density (∼6 J/cm{sup 2}) and multi-number of irradiation (≥50 times) contributed to high quality of alloyed layers after irradiation.

  9. Fractal parameterization analysis of ferroelectric domain structure evolution induced by electron beam irradiation

    Science.gov (United States)

    Maslovskaya, A. G.; Barabash, T. K.

    2017-01-01

    The article presents some results of fractal analysis of ferroelectric domain structure images visualized with scanning electron microscope (SEM) techniques. The fractal and multifractal characteristics were estimated to demonstrate self-similar organization of ferroelectric domain structure registered with static and dynamic contrast modes of SEM. Fractal methods as sensitive analytical tools were used to indicate degree of domain structure and domain boundary imperfections. The electron irradiation-induced erosion effect of ferroelectric domain boundaries in electron beam-stimulated polarization current mode of SEM is characterized by considerable raising of fractal dimension. For dynamic contrast mode of SEM there was revealed that complication of domain structure during its dynamics is specified by increase in fractal dimension of images and slight raising of boundary fractal dimension.

  10. Induced photonuclear interaction by Rhodotron-TT200 10 MeV electron beam

    Indian Academy of Sciences (India)

    Farshid Tabbakh; Mojtaba Mostajab Aldaavati; Mahdieh Hoseyni; Khadijeh Rezaee Ebrahim Saraee

    2012-02-01

    In this paper the photonuclear interaction induced by 10 MeV electron beam generating high-intensity neutrons is studied. Since the results depend on the target material, the calculations are performed for Pb, Ta and W targets which have high , in a simple geometry. MCNPX code has been used to simulate the whole process. Also, the results of photon generation has been compared with the experimental results to evaluate the reliability of the calculation. The results show that the obtained neutron flux can reach up to 1012 n/cm2 /s with average energies of 0.9 MeV, 0.4 MeV and 0.9 MeV for these three elements respectively with the maximum heat deposited as 3000 W/c3,4500 W/c3 and 6000 W/c3.

  11. Study of laser-induced plasma shock waves by the probe beam deflection technique

    Institute of Scientific and Technical Information of China (English)

    Yan Qian; Jian Lu; Xiaowu Ni

    2009-01-01

    Laser probe beam deflection technique is used for the analysis of laser-induced plasma shock waves in air and distilled water.The temporal and spatial variations of the parameters on shock fronts are studied as funotions of focal lens position and laser energy.The influences of the characteristics of media are investigated on the well-designed experimental setup.It is found that the shock wave in distilled water attenuates to an acoustic wave faster than in air under the same laser energy.Good agreement is obtained between our experimental results and those attained with other techniques.This technique is versatile,economic,and simple to implement,being a pronmising diagnostic tool for pulsed laser processing.

  12. Resonant antineutrino induced electron capture with low energy bound-beta beams

    CERN Document Server

    Oldeman, R G C; Saitta, B

    2009-01-01

    Antineutrino induced electron capture is a resonant process that can have a larg e cross-section for beams of monochromatic antineutrinos. We calculate the cross-section of this process and investigate an experimental setup where monochromatic antineutrinos are produced from the bound-beta decay of fully ionized radioactive atoms in a storage ring. If the energy between the source and the target is well matched, the cross-sections can be significantly larger than the cross-sections of commonly used non-resonant processes. The rate that can be achieved at a small distance between the source and two targets of $10^3$ kg is up to one interaction per $8 .3\\cdot10^{18}$ decaying atoms. For a source-target distance corresponding to the first atmospheric neutrino osc illation maximum, the largest rate is one interaction per $3.2\\cdot10^{21}$ decaying atoms.

  13. Three-dimensional core-shell ferromagnetic nanowires grown by focused electron beam induced deposition

    Science.gov (United States)

    Pablo-Navarro, Javier; Magén, César; María de Teresa, José

    2016-07-01

    Functional nanostructured materials often rely on the combination of more than one material to confer the desired functionality or an enhanced performance of the device. Here we report the procedure to create nanoscale heterostructured materials in the form of core-shell nanowires by focused electron beam induced deposition (FEBID) technologies. In our case, three-dimensional (3D) nanowires (nanostructures to demonstrate that the morphology of the shell is conserved during Pt coating, the surface oxidation is suppressed or confined to the Pt layer, and the average magnetization of the core is strengthened up to 30%. The proposed approach paves the way to the fabrication of 3D FEBID nanostructures based on the smart alternate deposition of two or more materials combining different physical properties or added functionalities.

  14. Solar cell evaluation using electron beam induced current with the large chamber scanning electron microscope

    Science.gov (United States)

    Wink, Tara; Kintzel, Edward; Marienhoff, Peter; Klein, Martin

    2012-02-01

    An initial study using electron beam induced current (EBIC) to evaluate solar cells has been carried out with the large chamber scanning electron microscope (LC-SEM) at the Western Kentucky University Nondestructive Analysis Center. EBIC is a scanning electron microscope technique used for the characterization of semiconductors. To facilitate our studies, we developed a Solar Amplification System (SASY) for analyzing current distribution and defects within a solar cell module. Preliminary qualitative results will be shown for a solar cell module that demonstrates the viability of the technique using the LC-SEM. Quantitative EBIC experiments will be carried out to analyze defects and minority carrier properties. Additionally, a well-focused spot of light from an LED mounted at the side of the SEM column will scan the same area of the solar cell using the LC-SEM positioning system. SASY will then output the solar efficiency to be compared with the minority carrier properties found using EBIC.

  15. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures

    KAUST Repository

    Mughal, Asad Jahangir

    2014-01-01

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material\\'s luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon. This journal is

  16. Band-gap engineering by molecular mechanical strain-induced giant tuning of the luminescence in colloidal amorphous porous silicon nanostructures.

    Science.gov (United States)

    Mughal, A; El Demellawi, J K; Chaieb, Sahraoui

    2014-12-14

    Nano-silicon is a nanostructured material in which quantum or spatial confinement is the origin of the material's luminescence. When nano-silicon is broken into colloidal crystalline nanoparticles, its luminescence can be tuned across the visible spectrum only when the sizes of the nanoparticles, which are obtained via painstaking filtration methods that are difficult to scale up because of low yield, vary. Bright and tunable colloidal amorphous porous silicon nanostructures have not yet been reported. In this letter, we report on a 100 nm modulation in the emission of freestanding colloidal amorphous porous silicon nanostructures via band-gap engineering. The mechanism responsible for this tunable modulation, which is independent of the size of the individual particles and their distribution, is the distortion of the molecular orbitals by a strained silicon-silicon bond angle. This mechanism is also responsible for the amorphous-to-crystalline transformation of silicon.

  17. Luminescence from Porous Silicon

    Directory of Open Access Journals (Sweden)

    A. Gupta

    1998-01-01

    Full Text Available Recent observations of photoluminescene (PL and electroluminescence (EL from poroussilicon (PS have prompted many theoretical and experimental studies. Bulk crystalline Si is anindirect band gap material in which .recombination is dominated by non-radiative processes.Therefore, it cannot be used as light-emitting component in Si circuits. PS is a new material formed byanodisation ofsingle crystal Si wafers in hydro fluoric (liF solution. Luminescence from this materialis being explored for technological applications all over the world. The mechanism of luminescence isstill not well-understood. Several models have been proposed but still the facts about the strong lightemission at room temperature are unknown. This paper presents a review of the fabrication process andstudies on luminescent properties of PS. A hybrid model based on quantum confinement of carriers inthe nanometer size Si crystallites having a large number of surface states is suggested to explain theobserved properties.

  18. Magnetic and fluorescent Gd2O3:Yb3+/Ln3+ nanoparticles for simultaneous upconversion luminescence/MR dual modal imaging and NIR-induced photodynamic therapy

    OpenAIRE

    LIU Jun; Huang, Long; Tian, Xiumei; Chen, Xiaoming; Shao, Yuanzhi; Xie, Fukang; Chen, Dihu; Li, Li

    2016-01-01

    The development of upconversion nanoparticles (UCNs) for theranostics application is a new strategy toward the accurate diagnosis and efficient treatment of cancer. Here, magnetic and fluorescent lanthanide-doped gadolinium oxide (Gd2O3) UCNs with bright upconversion luminescence (UCL) and high longitudinal relaxivity (r 1) are used for simultaneous magnetic resonance imaging (MRI)/UCL dual-modal imaging and photodynamic therapy (PDT). In vitro and in vivo MRI studies show that these products...

  19. Electron-beam irradiation induced transformation of Cu2(OH)3NO3 nanoflakes into nanocrystalline CuO

    Science.gov (United States)

    Padhi, S. K.; Gottapu, S. N.; Krishna, M. Ghanashyam

    2016-05-01

    The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural transformation that validate CHN modification. High-resolution transmission electron microscopy imaging of e-beam irradiated regions unambiguously supports the growth of CuO nanoparticles (11.8(3.2) nm in diameter). This study demonstrates e-beam irradiation induced CHN depletion, subsequent nucleation and growth of nanocrystalline CuO regions well embedded in the parent burnt porous matrix which can be useful for miniaturized sensing applications. NaBH4 induced room temperature reduction of CHN to elemental Cu and its printability on paper was also demonstrated.The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural

  20. Magnetic and fluorescent Gd2O3:Yb(3+)/Ln(3+) nanoparticles for simultaneous upconversion luminescence/MR dual modal imaging and NIR-induced photodynamic therapy.

    Science.gov (United States)

    Liu, Jun; Huang, Long; Tian, Xiumei; Chen, Xiaoming; Shao, Yuanzhi; Xie, Fukang; Chen, Dihu; Li, Li

    The development of upconversion nanoparticles (UCNs) for theranostics application is a new strategy toward the accurate diagnosis and efficient treatment of cancer. Here, magnetic and fluorescent lanthanide-doped gadolinium oxide (Gd2O3) UCNs with bright upconversion luminescence (UCL) and high longitudinal relaxivity (r1) are used for simultaneous magnetic resonance imaging (MRI)/UCL dual-modal imaging and photodynamic therapy (PDT). In vitro and in vivo MRI studies show that these products can serve as good MRI contrast agents. The bright upconversion luminescence of the products allows their use as fluorescence nanoprobes for live cells imaging. We also utilized the luminescence-emission capability of the UCNs for the activation of a photosensitizer to achieve significant PDT results. To the best of our knowledge, this study is the first use of lanthanide-doped Gd2O3 UCNs in a theranostics application. This investigation provides a useful platform for the development of Gd2O3-based UCNs for clinical diagnosis, treatment, and imaging-guided therapy of cancer.

  1. Determination of uranium(VI) sorbed species in calcium silicate hydrate phases: a laser-induced luminescence spectroscopy and batch sorption study.

    Science.gov (United States)

    Tits, Jan; Geipel, Gerhard; Macé, Nathalie; Eilzer, Manuela; Wieland, Erich

    2011-07-01

    Batch sorption experiments and time-resolved luminescence spectroscopy investigations were carried out to study the U(VI) speciation in calcium silicate hydrates for varying chemical conditions representing both fresh and altered cementitious environments. U(VI) uptake was found to be fast and sorption distribution ratios (R(d) values) were very high indicating strong uptake by the C-S-H phases. In addition a strong dependence of pH and solid composition (Ca:Si mol ratio) was observed. U(VI) luminescence spectroscopy investigations showed that the U(VI) solid speciation continuously changed over a period up to 6 months in contrast to the fast sorption kinetics observed in the batch sorption studies. Decay profile analysis combined with factor analysis of series of spectra of U(VI)-C-S-H suspensions, recorded with increasing delay times, revealed the presence of four luminescent U(VI) species in C-S-H suspensions, in agreement with the batch sorption data. Along with the aqueous UO(2)(OH)(4)(2-) species and a Ca-uranate precipitate, two different sorbed species were identified which are either bound to silanol groups on the surface or incorporated in the interlayer of the C-S-H structure.

  2. Magnetic and fluorescent Gd2O3:Yb3+/Ln3+ nanoparticles for simultaneous upconversion luminescence/MR dual modal imaging and NIR-induced photodynamic therapy

    Science.gov (United States)

    Liu, Jun; Huang, Long; Tian, Xiumei; Chen, Xiaoming; Shao, Yuanzhi; Xie, Fukang; Chen, Dihu; Li, Li

    2017-01-01

    The development of upconversion nanoparticles (UCNs) for theranostics application is a new strategy toward the accurate diagnosis and efficient treatment of cancer. Here, magnetic and fluorescent lanthanide-doped gadolinium oxide (Gd2O3) UCNs with bright upconversion luminescence (UCL) and high longitudinal relaxivity (r1) are used for simultaneous magnetic resonance imaging (MRI)/UCL dual-modal imaging and photodynamic therapy (PDT). In vitro and in vivo MRI studies show that these products can serve as good MRI contrast agents. The bright upconversion luminescence of the products allows their use as fluorescence nanoprobes for live cells imaging. We also utilized the luminescence-emission capability of the UCNs for the activation of a photosensitizer to achieve significant PDT results. To the best of our knowledge, this study is the first use of lanthanide-doped Gd2O3 UCNs in a theranostics application. This investigation provides a useful platform for the development of Gd2O3-based UCNs for clinical diagnosis, treatment, and imaging-guided therapy of cancer. PMID:28031709

  3. Radiation induced currents in parallel plate ionization chambers: measurement and Monte Carlo simulation for megavoltage photon and electron beams.

    Science.gov (United States)

    Abdel-Rahman, Wamied; Seuntjens, Jan P; Verhaegen, Frank; Podgorsak, Ervin B

    2006-09-01

    Polarity effects in ionization chambers are caused by a radiation induced current, also known as Compton current, which arises as a charge imbalance due to charge deposition in electrodes of ionization chambers. We used a phantom-embedded extrapolation chamber (PEEC) for measurements of Compton current in megavoltage photon and electron beams. Electron contamination of photon beams and photon contamination of electron beams have a negligible effect on the measured Compton current. To allow for a theoretical understanding of the Compton current produced in the PEEC effect we carried out Monte Carlo calculations with a modified user code, the COMPTON/ EGSnrc. The Monte Carlo calculated COMPTON currents agree well with measured data for both photon and electron beams; the calculated polarity correction factors, on the other hand, do not agree with measurement results. The conclusions reached for the PEEC can be extended to parallel-plate ionization chambers in general.

  4. Refractive index changes induced by sheet beams with various intensity distributions in LiNbO3:Fe crystal

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Peng; ZHAO; Jianlin; XU; Honglai; SUN; Yidong; YANG

    2005-01-01

    According to the Kukhtarev equations and a simplified model based on the photovoltaic charge carriers transport mechanism, the distributions of the index changes (DICs) in LiNbO3:Fe crystals induced by sheet beams with various intensity profiles are theoretically analyzed. The numerically simulated results coincide with the analytic expressions deduced from the simplified model. The DICs in a LiNbO3:Fe crystal induced by sheet beams with rectangular, Gaussian and square law profiles are measured by using the interferometric method. By employing the analytic expressions, the experimental data points are well fitted. By utilizing the angular spectrum theory and the ray equation, the uniformities of the intensity profiles of the writing beams along the propagation directions and the influences of the self-defocusing effect of the crystal are numerically simulated, respectively. The results show that the experimental results are reliable. The numerically simulated method and the analytic expressions can be both employed to predict the DICs induced by sheet beams with various light intensity profiles. Furthermore, utilizing writing beams with proper intensity profiles, any desired index distributions could be obtained.

  5. Suppression of Space Charge Induced Beam Halo in Nonlinear Focusing Channel

    CERN Document Server

    Batygin, Yuri K; Kurennoy, Sergey; Li, Chao

    2016-01-01

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.

  6. Suppression of space charge induced beam halo in nonlinear focusing channel

    Science.gov (United States)

    Batygin, Yuri K.; Scheinker, Alexander; Kurennoy, Sergey; Li, Chao

    2016-04-01

    An intense non-uniform particle beam exhibits strong emittance growth and halo formation in focusing channels due to nonlinear space charge forces of the beam. This phenomenon limits beam brightness and results in particle losses. The problem is connected with irreversible distortion of phase space volume of the beam in conventional focusing structures due to filamentation in phase space. Emittance growth is accompanied by halo formation in real space, which results in inevitable particle losses. A new approach for solving a self-consistent problem for a matched non-uniform beam in two-dimensional geometry is discussed. The resulting solution is applied to the problem of beam transport, while avoiding emittance growth and halo formation by the use of nonlinear focusing field. Conservation of a beam distribution function is demonstrated analytically and by particle-in-cell simulation for a beam with a realistic beam distribution.

  7. Environmental analysis based on luminescence in organized supramolecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Santana Rodriguez, J.J.; Betancort Rodriguez, J.R. [University of Las Palmas de G.C., Department of Chemistry, Faculty of Marine Sciences, Las Palmas (Spain); Halko, R. [Comenius University, Department of Analytical Chemistry, Faculty of Natural Sciences, Bratislava (Slovakia); Aaron, J.J. [Universite Paris 7-Denis Diderot, ITODYS, Paris (France)

    2006-06-15

    The use of organized supramolecular systems - including micellar media and cyclodextrin inclusion complexes - combined with luminescence techniques in the study and determination of compounds and elements of environmental interest from 1990 to 2005 is reviewed. Analyses of environmental samples performed using fluorescence, photochemically induced fluorescence and phosphorescence spectroscopy as well as liquid chromatography, capillary electrophoresis and flow injection with luminescence detection in the presence of these organized media are described in detail. (orig.)

  8. Study of the beam-induced neutron flux and required shielding for DIANA

    Energy Technology Data Exchange (ETDEWEB)

    Best, Andreas, E-mail: abest1@nd.edu [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Couder, Manoel [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Famiano, Michael [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States); Lemut, Alberto [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Wiescher, Michael [Department of Physics and The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States)

    2013-11-01

    Low energy accelerators in underground locations have emerged as a powerful tool for the measurement of critical nuclear reactions for the study of energy production and element synthesis in astrophysics. While cosmic ray induced background is substantially reduced, beam induced background on target impurities and depositions on target and collimator materials remain a matter of serious concern. The Dual Ion Accelerator for Nuclear Astrophysics (DIANA) is proposed to operate as a low-level background facility in an underground location. One of the main goals of DIANA is the study of neutron sources in stellar helium burning. For these experiments DIANA is a neutron radiation source which may affect other nearby low background level experiments. We therefore investigated the required laboratory layout to attenuate the neutron flux generated in a worst-case scenario to a level below the natural background in the underground environment. Detailed Monte Carlo calculations of the neutron propagation in the laboratory show that a neutron flux many orders of magnitude above expected values gets attenuated below the natural background rate using a 1 m thick water-shielded door as well as an emergency access/egress maze.

  9. Latent tracks in sapphire induced by 20-MeV fullerene beams

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, S.M.; Bonardi, N.; Canut, B. [Departement de Physique des Materiaux (UMR CNRS 5586), Universite Claude Bernard Lyon I, 69622 Villeurbanne Cedex (France); Della-Negra, S. [Institut de Physique Nucleaire, CNRS-IN2P3, 91406 Orsay (France)

    1998-01-01

    Single crystals of {alpha}-Al{sub 2}O{sub 3} were irradiated with 20-MeV fullerene beams in a fluence range from 1.0{times}10{sup 10} to 2.2{times}10{sup 11} C{sub 60}{sup +}cm{sup {minus}2}. The cluster electronic stopping power (dE/dx){sub e} was approximately 62keVnm{sup {minus}1}. Two complementary techniques were employed to assess the modifications induced by these irradiations: Rutherford-backscattering spectrometry in channeling geometry (RBS-C) and transmission electron microscopy (TEM). The disorder induced by electronic processes is clearly determined by the RBS-C analysis. A damage cross section A{sub e} of about 2.2{times}10{sup {minus}12}cm{sup 2} has been extracted from the disorder kinetics, which corresponds to a track radius of {approx}8.5nm. From lattice-disorder profiling, a maximal decorrelation length of the C{sub 60} clusters in the crystal was estimated to be {approx}150nm. TEM micrographs exhibit cylindrical latent tracks formed around the projectile trajectory, while the high-resolution observations evidence the amorphization of sapphire in the core of these tracks. The present results have been interpretated within a model of high locally deposited energy densities in the cluster irradiation regime. {copyright} {ital 1998} {ital The American Physical Society}

  10. Room Temperature Ion-Beam-Induced Recrystallization and Large Scale Nanopatterning.

    Science.gov (United States)

    Satpati, Biswarup; Ghosh, Tanmay

    2015-02-01

    We have studied ion-induced effects in the near-surface region of two eutectic systems. Gold and Silver nanodots on Silicon (100) substrate were prepared by thermal evaporation under high vacuum condition at room temperature (RT) and irradiated with 1.5 MeV Au2+ ions at flux ~1.25 x 10(11) ions cm-2 s-1 also at RT. These samples were characterized using cross-sectional transmission electron microscopy (XTEM) and associated techniques. We have observed that gold act as catalysis in the recrystallization process of ion-beam-induced amorphous Si at room temperature and also large mass transport up to a distance of about 60 nm into the substrate. Mass transport is much beyond the size (~ 6-20 nm) of these Au nanodots. Ag nanoparticles with diameter 15-45 nm are half-way embedded into the Si substrate and does not stimulate in recrystallization. In case of Au nanoparticles upon ion irradiation, mixed phase formed only when the local composition and transient temperature during irradiation is sufficient to cause mixing in accordance with the Au-Si stable phase diagram. Spectroscopic imaging in the scanning TEM using spatially resolved electron energy loss spectroscopy provides one of the few ways to measure the real-space nanoscale mixing.

  11. Study on Nanostructures Induced by High-Current Pulsed Electron Beam

    Directory of Open Access Journals (Sweden)

    Bo Gao

    2012-01-01

    Full Text Available Four techniques using high-current pulsed electron beam (HCPEB were proposed to obtain surface nanostructure of metal and alloys. The first method involves the distribution of several fine Mg nanoparticles on the top surface of treated samples by evaporation of pure Mg with low boiling point. The second technique uses superfast heating, melting, and cooling induced by HCPEB irradiation to refine the primary phase or the second phase in alloys to nanosized uniform distributed phases in the matrix, such as the quasicrystal phase Mg30Zn60Y10 in the quasicrystal alloy Mg67Zn30Y3. The third technique involves the refinement of eutectic silicon phase in hypereutectic Al-15Si alloys to fine particles with the size of several nanometers through solid solution and precipitation refinement. Finally, in the deformation zone induced by HCPEB irradiation, the grain size can be refined to several hundred nanometers, such as the grain size of the hypereutectic Al-15Si alloys in the deformation zone, which can reach ~400 nm after HCPEB treatment for 25 pulses. Therefore, HCPEB technology is an efficient way to obtain surface nanostructure.

  12. Structural changes and relaxations monitored by luminescence.

    Science.gov (United States)

    Wang, Y; Yang, B; Townsend, P D

    2013-01-01

    Luminescence data have often been used to study imperfections and to characterize lattice distortions because the signals are sensitive to changes of structure and composition. Previous studies have included intentionally added probe ions such as rare earth ions to sense distortions in local crystal fields caused by modified structural environments. An under-exploited extension of this approach was to use luminescence to monitor crystalline phase changes. A current overview of this new and powerful technique shows that continuous scanning of the sample temperatures immediately offered at least three types of signatures for phase transitions. Because of high sensitivity, luminescence signals were equally responsive to structural changes from inclusions and nanoparticles. These coupled to the host material via long-range interactions and modified the host signals. Two frequently observed examples that are normally overlooked are from nanoparticle inclusions of water and CO2. Examples also indicated that phase transitions were detected in more diverse materials such as superconductors and fullerenes. Finally, luminescence studies have shown that in some crystalline examples, high dose ion implantation of surface layers could induce relaxations and/or structural changes of the entire underlying bulk material. This was an unexpected result and therefore such a possibility has not previously been explored. However, the implications for ion implication are significant and could be far more general than the examples mentioned here.

  13. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    2001-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible luminescenc

  14. Electron-beam irradiation induced transformation of Cu2(OH)3NO3 nanoflakes into nanocrystalline CuO.

    Science.gov (United States)

    Padhi, S K; Gottapu, S N; Krishna, M Ghanashyam

    2016-06-07

    The transmission electron microscope electron-beam (TEM e-beam) as a material modification tool has been demonstrated. The material modification is realised in the high-resolution TEM mode (largest condenser aperture, 150 μm, and 200 nm spot size) at a 200 keV beam energy. The Cu2(OH)3NO3 (CHN) nanoflakes used in this study were microwave solution processed that were layered single crystals and radiation sensitive. The single domain CHN flakes disintegrate into a large number of individual CuO crystallites within a 90 s span of time. The sequential bright-field, dark-field, and selected area electron diffraction modes were employed to record the evolved morphology, microstructural changes, and structural transformation that validate CHN modification. High-resolution transmission electron microscopy imaging of e-beam irradiated regions unambiguously supports the growth of CuO nanoparticles (11.8(3.2) nm in diameter). This study demonstrates e-beam irradiation induced CHN depletion, subsequent nucleation and growth of nanocrystalline CuO regions well embedded in the parent burnt porous matrix which can be useful for miniaturized sensing applications. NaBH4 induced room temperature reduction of CHN to elemental Cu and its printability on paper was also demonstrated.

  15. NanoSQUID magnetometry of individual cobalt nanoparticles grown by focused electron beam induced deposition

    Science.gov (United States)

    Martínez-Pérez, M. J.; Müller, B.; Schwebius, D.; Korinski, D.; Kleiner, R.; Sesé, J.; Koelle, D.

    2017-02-01

    We demonstrate the operation of low-noise nano superconducting quantum interference devices (SQUIDs) based on the high critical field and high critical temperature superconductor YBa2Cu3O7 (YBCO) as ultra-sensitive magnetometers for single magnetic nanoparticles (MNPs). The nanoSQUIDs exploit the Josephson behavior of YBCO grain boundaries and have been patterned by focused ion beam milling. This allows us to precisely define the lateral dimensions of the SQUIDs so as to achieve large magnetic coupling between the nanoloop and individual MNPs. By means of focused electron beam induced deposition, cobalt MNPs with a typical size of several tens of nm have been grown directly on the surface of the sensors with nanometric spatial resolution. Remarkably, the nanoSQUIDs are operative over extremely broad ranges of applied magnetic field (-1 T \\lt {μ }0H\\lt 1 T) and temperature (0.3 K \\lt T\\lt 80 K). All these features together have allowed us to perform magnetization measurements under different ambient conditions and to detect the magnetization reversal of individual Co MNPs with magnetic moments (1-30) × {10}6 {μ }{{B}}. Depending on the dimensions and shape of the particles we have distinguished between two different magnetic states yielding different reversal mechanisms. The magnetization reversal is thermally activated over an energy barrier, which has been quantified for the (quasi) single-domain particles. Our measurements serve to show not only the high sensitivity achievable with YBCO nanoSQUIDs, but also demonstrate that these sensors are exceptional magnetometers for the investigation of the properties of individual nanomagnets.

  16. Parameters Optimization of Laser-Induced Breakdown Spectroscopy Experimental Setup for the Case with Beam Expander

    Science.gov (United States)

    Wang, Xin; Zhang, Lei; Fan, Juanjuan; Li, Yufang; Gong, Yao; Dong, Lei; Ma, Weiguang; Yin, Wangbao; Jia, Suotang

    2015-11-01

    Improvement of measurement precision and repeatability is one of the issues currently faced by the laser-induced breakdown spectroscopy (LIBS) technique, which is expected to be capable of precise and accurate quantitative analysis. It was found that there was great potential to improve the signal quality and repeatability by reducing the laser beam divergence angle using a suitable beam expander (BE). In the present work, the influences of several experimental parameters for the case with BE are studied in order to optimize the analytical performances: the signal to noise ratio (SNR) and the relative standard deviation (RSD). We demonstrate that by selecting the optimal experimental parameters, the BE-included LIBS setup can give higher SNR and lower RSD values of the line intensity normalized by the whole spectrum area. For validation purposes, support vector machine (SVM) regression combined with principal component analysis (PCA) was used to establish a calibration model to realize the quantitative analysis of the ash content. Good agreement has been found between the laboratory measurement results from the LIBS method and those from the traditional method. The measurement accuracy presented here for ash content analysis is estimated to be 0.31%, while the average relative error is 2.36%. supported by the 973 Program of China (No. 2012CB921603), National Natural Science Foundation of China (Nos. 61475093, 61127017, 61178009, 61108030, 61378047, 61275213, 61475093, and 61205216), the National Key Technology R&D Program of China (No. 2013BAC14B01), the Shanxi Natural Science Foundation (Nos. 2013021004-1 and 2012021022-1), the Shanxi Scholarship Council of China (Nos. 2013-011 and 2013-01), and the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi, China

  17. High resolution laser beam induced current images under trichromatic laser radiation: approximation to the solar irradiation.

    Science.gov (United States)

    Navas, F J; Alcántara, R; Fernández-Lorenzo, C; Martín-Calleja, J

    2010-03-01

    A laser beam induced current (LBIC) map of a photoactive surface is a very useful tool when it is necessary to study the spatial variability of properties such as photoconverter efficiency or factors connected with the recombination of carriers. Obtaining high spatial resolution LBIC maps involves irradiating the photoactive surface with a photonic beam with Gaussian power distribution and with a low dispersion coefficient. Laser emission fulfils these characteristics, but against it is the fact that it is highly monochromatic and therefore has a spectral distribution different to solar emissions. This work presents an instrumental system and procedure to obtain high spatial resolution LBIC maps in conditions approximating solar irradiation. The methodology developed consists of a trichromatic irradiation system based on three sources of laser excitation with emission in the red, green, and blue zones of the electromagnetic spectrum. The relative irradiation powers are determined by either solar spectrum distribution or Planck's emission formula which provides information approximate to the behavior of the system if it were under solar irradiation. In turn, an algorithm and a procedure have been developed to be able to form images based on the scans performed by the three lasers, providing information about the photoconverter efficiency of photovoltaic devices under the irradiation conditions used. This system has been checked with three photosensitive devices based on three different technologies: a commercial silicon photodiode, a commercial photoresistor, and a dye-sensitized solar cell. These devices make it possible to check how the superficial quantum efficiency has areas dependent upon the excitation wavelength while it has been possible to measure global incident photon-to-current efficiency values approximating those that would be obtained under irradiation conditions with sunlight.

  18. Potential For Laser-Induced Microbunching Studies with the 3-MHZ-Rate Electron Beams at ASTA

    CERN Document Server

    Lumpkin, A H; Byrd, J M; Wilcox, R B

    2014-01-01

    Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the ASTA facility. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the...

  19. Controlling electron beam-induced structure modifications and cation exchange in cadmium sulfide–copper sulfide heterostructured nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Haimei [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sadtler, Bryce; Habenicht, Carsten [Department of Chemistry, University of California, Berkeley, CA 94720 (United States); Freitag, Bert [FEI Company, P.O. Box 80066, KA 5600 Eindhoven (Netherlands); Alivisatos, A. Paul [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Department of Chemistry, University of California, Berkeley, CA 94720 (United States); Kisielowski, Christian, E-mail: CFKisielowski@lbl.gov [National Center for Electron Microcopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Joint Center for Artificial Photosynthesis, Berkeley, CA 94720 (United States)

    2013-11-15

    The atomic structure and interfaces of CdS/Cu{sub 2}S heterostructured nanorods are investigated with the aberration-corrected TEAM 0.5 electron microscope operated at 80 kV and 300 kV applying in-line holography and complementary techniques. Cu{sub 2}S exhibits a low-chalcocite structure in pristine CdS/Cu{sub 2}S nanorods. Under electron beam irradiation the Cu{sub 2}S phase transforms into a high-chalcocite phase while the CdS phase maintains its wurtzite structure. Time-resolved experiments reveal that Cu{sup +}–Cd{sup 2+} cation exchange at the CdS/Cu{sub 2}S interfaces is stimulated by the electron beam and proceeds within an undisturbed and coherent sulfur sub-lattice. A variation of the electron beam current provides an efficient way to control and exploit such irreversible solid-state chemical processes that provide unique information about system dynamics at the atomic scale. Specifically, we show that the electron beam-induced copper–cadmium exchange is site specific and anisotropic. A resulting displacement of the CdS/Cu{sub 2}S interfaces caused by beam-induced cation interdiffusion equals within a factor of 3–10 previously reported Cu diffusion length measurements in heterostructured CdS/Cu{sub 2}S thin film solar cells with an activation energy of 0.96 eV. - Highlights: • Heterostructured nanorods were investigated at atomic resolution showing that they are free of extended defects. • Beam–sample interactions are controlled by current and voltage variations to provide pristine crystal structures. • Beam-induced migration of heterointerfaces are measured time-resolved and compared with Cu diffusion coefficients. • Beam–sample interaction overwrite possible signal improvements that can be expected by sample cooling.

  20. Evidence of liquid phase during laser-induced periodic surface structures formation induced by accumulative ultraviolet picosecond laser beam

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, T. T. D.; Petit, A.; Semmar, N., E-mail: nadjib.semmar@univ-orleans.fr [GREMI, UMR7344, CNRS/University of Orleans, 14 rue d' Issoudun, BP6744, 45067 Orleans Cedex 2 (France); Vayer, M. [ICMN, UMR 7374, CNRS/University of Orleans, 1b rue de la Ferollerie, CS 40059, 45071 Orleans Cedex (France); Sauldubois, A. [CME, UFR Sciences, University of Orleans, 1 Rue de Chartres, BP 6759, 45067 Orleans Cedex 2 (France)

    2015-11-09

    Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10 Hz, and 30 mJ/cm{sup 2}). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation. Atomic Force Microscopy (AFM) analyses have shown the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phase during the LIPSS formation in the picosecond regime.

  1. Evidence of liquid phase during laser-induced periodic surface structures formation induced by accumulative ultraviolet picosecond laser beam

    Science.gov (United States)

    Huynh, T. T. D.; Vayer, M.; Sauldubois, A.; Petit, A.; Semmar, N.

    2015-11-01

    Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10 Hz, and 30 mJ/cm2). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation. Atomic Force Microscopy (AFM) analyses have shown the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phase during the LIPSS formation in the picosecond regime.

  2. Synthesis of nanowires via helium and neon focused ion beam induced deposition with the gas field ion microscope.

    Science.gov (United States)

    Wu, H M; Stern, L A; Chen, J H; Huth, M; Schwalb, C H; Winhold, M; Porrati, F; Gonzalez, C M; Timilsina, R; Rack, P D

    2013-05-03

    The ion beam induced nanoscale synthesis of platinum nanowires using the trimethyl (methylcyclopentadienyl)platinum(IV) (MeCpPt(IV)Me3) precursor is investigated using helium and neon ion beams in the gas field ion microscope. The He(+) beam induced deposition resembles material deposited by electron beam induced deposition with very small platinum nanocrystallites suspended in a carbonaceous matrix. The He(+) deposited material composition was estimated to be 16% Pt in a matrix of amorphous carbon with a large room-temperature resistivity (∼3.5 × 10(4)-2.2 × 10(5) μΩ cm) and temperature-dependent transport behavior consistent with a granular material in the weak intergrain tunnel coupling regime. The Ne(+) deposited material has comparable composition (17%), however a much lower room-temperature resistivity (∼600-3.0 × 10(3) μΩ cm) and temperature-dependent electrical behavior representative of strong intergrain coupling. The Ne(+) deposited nanostructure has larger platinum nanoparticles and is rationalized via Monte Carlo ion-solid simulations which show that the neon energy density deposited during growth is much larger due to the smaller ion range and is dominated by nuclear stopping relative to helium which has a larger range and is dominated by electronic stopping.

  3. Ongoing characterization of the forced electron beam induced arc discharge ion source for the selective production of exotic species facility

    Energy Technology Data Exchange (ETDEWEB)

    Manzolaro, M., E-mail: mattia.manzolaro@lnl.infn.it; Andrighetto, A.; Monetti, A.; Scarpa, D.; Rossignoli, M.; Vasquez, J.; Corradetti, S.; Calderolla, M.; Prete, G. [INFN, Laboratori Nazionali di Legnaro, Viale dell’Universita’ 2 - 35020 Legnaro, Padova,Italy (Italy); Meneghetti, G. [Department of Industrial Engineering, University of Padova, Via Venezia 1 - 35131 Padova (Italy)

    2014-02-15

    An intense research and development activity to finalize the design of the target ion source system for the selective production of exotic species (SPES) facility (operating according to the isotope separation on line technique) is at present ongoing at Legnaro National Laboratories. In particular, the characterization of ion sources in terms of ionization efficiency and transversal emittance is currently in progress, and a preliminary set of data is already available. In this work, the off-line ionization efficiency and emittance measurements for the SPES forced electron beam induced arc discharge ion source in the case of a stable Ar beam are presented in detail.

  4. Reaction dynamics induced by the radioactive ion beam 7Be on medium-mass and heavy targets

    Science.gov (United States)

    Mazzocco, M.; Boiano, A.; Boiano, C.; La Commara, M.; Manea, C.; Parascandolo, C.; Pierroutsakou, D.; Stefanini, C.; Strano, E.; Torresi, D.; Acosta, L.; Di Meo, P.; Fernandez-Garcia, J. P.; Glodariu, T.; Grebosz, J.; Guglielmetti, A.; Keeley, N.; Lay, J. A.; Marquinez-Duran, G.; Martel, I.; Mazzocchi, C.; Molini, P.; Nicoletto, M.; Pakou, A.; Parkar, V. V.; Rusek, K.; Sánchez-Benítez, A. M.; Sandoli, M.; Sava, T.; Sgouros, O.; Signorini, C.; Silvestri, R.; Soramel, F.; Soukeras, V.; Stiliaris, E.; Stroe, L.; Toniolo, N.; Zerva, K.

    2015-10-01

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam 7Be (Sα = 1.586 MeV) on medium-mass (58Ni) and heavy (208Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×105 pps 7Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  5. Reflection High-Energy Electron Diffraction Beam-Induced Structural and Property Changes on WO3 Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Du, Yingge; Zhang, Hongliang; Varga, Tamas; Chambers, Scott A.

    2014-08-08

    Reduction of transition metal oxides can greatly change their physical and chemical properties. Using deposition of WO3 as a case study, we demonstrate that reflection high-energy electron diffraction (RHEED), a surface-sensitive tool widely used to monitor thin-film deposition processes, can significantly affect the cation valence and physical properties of the films through electron-beam induced sample reduction. The RHEED beam is found to increase film smoothness during epitaxial growth of WO3, as well as change the electronic properties of the film through preferential removal of surface oxygen.

  6. Thermal conductivity of graphene with defects induced by electron beam irradiation

    Science.gov (United States)

    Malekpour, Hoda; Ramnani, Pankaj; Srinivasan, Srilok; Balasubramanian, Ganesh; Nika, Denis L.; Mulchandani, Ashok; Lake, Roger K.; Balandin, Alexander A.

    2016-07-01

    We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ~7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 1010 cm-2 to 1.8 × 1011 cm-2 the thermal conductivity decreases from ~(1.8 +/- 0.2) × 103 W mK-1 to ~(4.0 +/- 0.2) × 102 W mK-1 near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ~400 W mK-1. The thermal conductivity dependence on the defect density is

  7. Study of Thermo-Mechanical Effects Induced in Solids by High Energy Particle Beams: Analytical and Numerical Methods

    CERN Document Server

    Dallocchio, Alessandro; Kurtyka, T; Bertarelli, A

    2008-01-01

    Requirements of modern nuclear physics entail big efforts in the field of particle accelerator technology in order to build powerful machines providing particle beams at higher and higher energies; in this context, the Large Hadron Collider represents the future for particle physics. The LHC stores 360 MJ for each circulating beam; this large amount of energy is potentially destructive for accelerator equipments having direct interaction with particles; the need to handle high thermal loads bestows strategic importance to the study of thermo-mechanical problems in accelerator devices. The aim of this work is the study of thermo-mechanical effects induced in solids by high energy particle beams. Development of facilities devoted to the experimental test of accelerator equipments in real working conditions presents several technical difficulties and high cost; the importance of developing reliable methods and accurate models that could be efficiently applied during the design phase of the most critical particle...

  8. Raman study of localized recrystallization of amorphous silicon induced by laser beam

    KAUST Repository

    Tabet, Nouar A.

    2012-06-01

    The adoption of amorphous silicon based solar cells has been drastically hindered by the low efficiency of these devices, which is mainly due to a low hole mobility. It has been shown that using both crystallized and amorphous silicon layers in solar cells leads to an enhancement of the device performance. In this study the crystallization of a-Si prepared by PECVD under various growth conditions has been investigated. The growth stresses in the films are determined by measuring the curvature change of the silicon substrate before and after film deposition. Localized crystallization is induced by exposing a-Si films to focused 532 nm laser beam of power ranging from 0.08 to 8 mW. The crystallization process is monitored by recording the Raman spectra after various exposures. The results suggest that growth stresses in the films affect the minimum laser power (threshold power). In addition, a detailed analysis of the width and position of the Raman signal indicates that the silicon grains in the crystallized regions are of few nm diameter. © 2012 IEEE.

  9. Nitrogen as a carrier gas for regime control in focused electron beam induced deposition

    Directory of Open Access Journals (Sweden)

    Wachter Stefan

    2014-01-01

    Full Text Available This work reports on focused electron beam induced deposition (FEBID using a custom built gas injection system (GIS equipped with nitrogen as a gas carrier. We have deposited cobalt from Co2(CO8, which is usually achieved by a heated GIS. In contrast to a heated GIS, our strategy allows avoiding problems caused by eventual temperature gradients along the GIS. Moreover, the use of the gas carrier enables a high control over process conditions and consequently the properties of the synthesized nanostructures. Chemical composition and growth rate are investigated by energy dispersive X-ray spectroscopy (EDX and atomic force microscopy (AFM, respectively. We demonstrate that the N2 flux is strongly affecting the deposit growth rate without the need of heating the precursor in order to increase its vapour pressure. Particularly, AFM volume estimation of the deposited structures showed that increasing the nitrogen resulted in an enhanced deposition rate. The wide range of achievable precursor fluxes allowed to clearly distinguish between precursor- and electron-limited regime. With the carrier-based GIS an optimized deposition procedure with regards to the desired deposition regime has been enabled

  10. Fabrication of PEFC membrane based on perfluorinated polymer using quantum beam induced grafting technique

    Science.gov (United States)

    Oshima, Akihiro; Sato, Yukiko; Shiraki, Fumiya; Mitani, Naohiro; Fujii, Kazuki; Oshima, Yuji; Fujita, Hajime; Washio, Masakazu

    2011-02-01

    The performance of a polymer electrolyte fuel cell (PEFC) is affected by the interfacial property between the proton exchange membrane (PEM) and the electrodes. Thus, development of well-laminated membrane electrode assemblies (MEAs) has been carried out. The hybrid PEM, consisting of perfluoro-sulfonic acid (PFSA) ionomer and sulfonated polystyrene grafted tetrafluoroethylene-co-hexafluoropropylene (sulfonated PS-g-FEP) synthesized by the soft electron beam (soft-EB) induced grafting method, was fabricated by mixing sulfonated PS-g-FEP with PFSA ionomer, which is coated on the interface of the PEM and the electrodes. The obtained hybrid PEM was characterized in terms of water uptake, ion exchange capacity, polarization performance and electrochemical impedance. The ion exchange capacity (IEC) of the hybrid PEM was 1.0-1.2 meq/g. The polarization curve and electrochemical impedance of the hybrid PEM was analyzed. As a result, the ionic conductivity was 0.16 S/cm and is the highest in the tested PEMs. The maximum power density is about 1.0 W/cm 2 with low humidity (relative humidity RH: 16%), which is 1.5 times higher than that of commercially available Nafion ® 112.

  11. Fabrication of PEFC membrane based on perfluorinated polymer using quantum beam induced grafting technique

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Akihiro, E-mail: akoshima@sanken.osaka-u.ac.j [Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Sato, Yukiko; Shiraki, Fumiya; Mitani, Naohiro; Fujii, Kazuki; Oshima, Yuji; Fujita, Hajime; Washio, Masakazu [Research Institute for Science and Engineering (RISE), Waseda University, 3-4-1 Okubo, Shinjuku 169-8555 (Japan)

    2011-02-15

    The performance of a polymer electrolyte fuel cell (PEFC) is affected by the interfacial property between the proton exchange membrane (PEM) and the electrodes. Thus, development of well-laminated membrane electrode assemblies (MEAs) has been carried out. The hybrid PEM, consisting of perfluoro-sulfonic acid (PFSA) ionomer and sulfonated polystyrene grafted tetrafluoroethylene-co-hexafluoropropylene (sulfonated PS-g-FEP) synthesized by the soft electron beam (soft-EB) induced grafting method, was fabricated by mixing sulfonated PS-g-FEP with PFSA ionomer, which is coated on the interface of the PEM and the electrodes. The obtained hybrid PEM was characterized in terms of water uptake, ion exchange capacity, polarization performance and electrochemical impedance. The ion exchange capacity (IEC) of the hybrid PEM was 1.0-1.2 meq/g. The polarization curve and electrochemical impedance of the hybrid PEM was analyzed. As a result, the ionic conductivity was 0.16 S/cm and is the highest in the tested PEMs. The maximum power density is about 1.0 W/cm{sup 2} with low humidity (relative humidity RH: 16%), which is 1.5 times higher than that of commercially available Nafion 112.

  12. Radiation induced microstructures in ODS 316 austenitic steel under dual-beam ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He Ken [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L3N6, Ontario (Canada); Yao, Zhongwen, E-mail: yaoz@me.queensu.ca [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L3N6, Ontario (Canada); Zhou, Zhangjian; Wang, Man [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Kaitasov, Odile [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, Orsay 91405 (France); Daymond, Mark R. [Department of Mechanical and Materials Engineering, Queen’s University, Kingston K7L3N6, Ontario (Canada)

    2014-12-15

    An ODS 316 austenitic steel was fabricated and irradiated using dual ion beams (1 MeV Kr{sup +} and 15 keV He{sup +}) with in-situ transmission electron microscope (TEM) observation. Cavities formed at a low dose in samples irradiated with simultaneous helium injection. It was found that Y–Ti–O particles acted as strong traps for cavity formation at low doses. Helium exhibited a significant effect on cavity development. Cavities were also preferentially nucleated along grain boundaries, phase boundaries and twin boundaries. Irradiation induced lattice defects mainly consisted of small 1/2〈1 1 0〉 perfect loops and 1/3〈1 1 1〉 Frank loops. An increment of helium injection rate also greatly enhanced the Frank loop growth. Small (<10 nm) Y–Ti–O particles were found to be unstable after irradiation to high doses. M{sub 23}C{sub 6} precipitates were observed after irradiation and helium might play a major role in their formation.

  13. Highly conductive and pure gold nanostructures grown by electron beam induced deposition

    Science.gov (United States)

    Shawrav, Mostafa M.; Taus, Philipp; Wanzenboeck, Heinz D.; Schinnerl, M.; Stöger-Pollach, M.; Schwarz, S.; Steiger-Thirsfeld, A.; Bertagnolli, Emmerich

    2016-09-01

    This work introduces an additive direct-write nanofabrication technique for producing extremely conductive gold nanostructures from a commercial metalorganic precursor. Gold content of 91 atomic % (at. %) was achieved by using water as an oxidative enhancer during direct-write deposition. A model was developed based on the deposition rate and the chemical composition, and it explains the surface processes that lead to the increases in gold purity and deposition yield. Co-injection of an oxidative enhancer enabled Focused Electron Beam Induced Deposition (FEBID)—a maskless, resistless deposition method for three dimensional (3D) nanostructures—to directly yield pure gold in a single process step, without post-deposition purification. Gold nanowires displayed resistivity down to 8.8 μΩ cm. This is the highest conductivity achieved so far from FEBID and it opens the possibility of applications in nanoelectronics, such as direct-write contacts to nanomaterials. The increased gold deposition yield and the ultralow carbon level will facilitate future applications such as the fabrication of 3D nanostructures in nanoplasmonics and biomolecule immobilization.

  14. Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide

    Science.gov (United States)

    Riazanova, A. V.; Costanzi, B. N.; Aristov, A. I.; Rikers, Y. G. M.; Mulders, J. J. L.; Kabashin, A. V.; Dahlberg, E. Dan; Belova, L. M.

    2016-03-01

    Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10-6 in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm-1. The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

  15. Spatial chemistry evolution during focused electron beam-induced deposition: origins and workarounds

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Robert; Geier, Barbara [Graz Centre for Electron Microscopy, Graz (Austria); Plank, Harald [Graz Centre for Electron Microscopy, Graz (Austria); Graz University of Technology, Institute for Electron Microscopy and Nanoanalysis, Graz (Austria)

    2014-12-15

    The successful application of functional nanostructures, fabricated via focused electron-beam-induced deposition (FEBID), is known to depend crucially on its chemistry as FEBID tends to strong incorporation of carbon. Hence, it is essential to understand the underlying mechanisms which finally determine the elemental composition after fabrication. In this study we focus on these processes from a fundamental point of view by means of (1) varying electron emission on the deposit surface; and (2) changing replenishment mechanism, both driven by the growing deposit itself. First, we revisit previous results concerning chemical variations in nanopillars (with a quasi-1D footprint) depending on the process parameters. In a second step we expand the investigations to deposits with a 3D footprint which are more relevant in the context of applications. Then, we demonstrate how technical setups and directional gas fluxes influence final chemistries. Finally, we put the findings in a bigger context with respect to functionalities which demonstrates the crucial importance of carefully set up fabrication processes to achieve controllable, predictable and reproducible chemistries for FEBID deposits as a key element for industrially oriented applications. (orig.)

  16. Surface Nanostructure Formations in an AISI 316L Stainless Steel Induced by Pulsed Electron Beam Treatment

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2015-01-01

    Full Text Available High current pulsed electron beam (HCPEB is an efficient technique for surface modifications of metallic materials. In the present work, the formations of surface nanostructures in an AISI 316L stainless steel induced by direct HCPEB treatment and HCPEB alloying have been investigated. After HCPEB Ti alloying, the sample surface contained a mixture of the ferrite and austenite phases with an average grain size of about 90 nm, because the addition of Ti favors the formation of ferrite. In contrast, electron backscattered diffraction (EBSD analyses revealed no structural refinement on the direct HCPEB treated sample. However, transmission electron microscope (TEM observations showed that fine cells having an average size of 150 nm without misorientations, as well as nanosized carbide particles, were formed in the surface layer after the direct HCPEB treatment. The formation of nanostructures in the 316L stainless steel is therefore attributed to the rapid solidification and the generation of different phases other than the steel substrate in the melted layer.

  17. Control of luminescence from pygmy shark (Squaliolus aliae) photophores.

    Science.gov (United States)

    Claes, Julien M; Ho, Hsuan-Ching; Mallefet, Jérôme

    2012-05-15

    The smalleye pygmy shark (Squaliolus aliae) is a dwarf pelagic shark from the Dalatiidae family that harbours thousands of tiny photophores. In this work, we studied the organisation and physiological control of these photogenic organs. Results show that they are mainly situated on the ventral side of the shark, forming a homogeneous ventral photogenic area that appears well suited for counterillumination, a well-known camouflage technique of pelagic organisms. Isolated ventral skin patches containing photophores did not respond to classical neurotransmitters and nitric oxide but produced light after melatonin (MT) application. Prolactin and α-melanocyte-stimulating hormone inhibited this hormonally induced luminescence as well as the spontaneous luminescence from the photogenic tissue. The action of MT seems to be mediated by binding to the MT(2) receptor subtype, as the MT(2) receptor agonist 4P-PDOT inhibited the luminescence induced by this hormone. Binding to this receptor probably decreases the intracellular cAMP concentration because forskolin inhibited spontaneous and MT-induced luminescence. In addition, a GABA inhibitory tonus seems to be present in the photogenic tissue as well, as GABA inhibited MT-induced luminescence and the application of bicuculline provoked luminescence from S. aliae photophores. Similarly to what has been found in Etmopteridae, the other luminous shark family, the main target of the luminescence control appears to be the melanophores covering the photocytes. Results suggest that bioluminescence first appeared in Dalatiidae when they adopted a pelagic style at the Cretaceous/Tertiary boundary, and was modified by Etmopteridae when they started to colonize deep-water niches and rely on this light for intraspecific behaviours.

  18. Carbon-ion beam irradiation kills X-ray-resistant p53-null cancer cells by inducing mitotic catastrophe.

    Directory of Open Access Journals (Sweden)

    Napapat Amornwichet

    Full Text Available BACKGROUND AND PURPOSE: To understand the mechanisms involved in the strong killing effect of carbon-ion beam irradiation on cancer cells with TP53 tumor suppressor gene deficiencies. MATERIALS AND METHODS: DNA damage responses after carbon-ion beam or X-ray irradiation in isogenic HCT116 colorectal cancer cell lines with and without TP53 (p53+/+ and p53-/-, respectively were analyzed as follows: cell survival by clonogenic assay, cell death modes by morphologic observation of DAPI-stained nuclei, DNA double-strand breaks (DSBs by immunostaining of phosphorylated H2AX (γH2AX, and cell cycle by flow cytometry and immunostaining of Ser10-phosphorylated histone H3. RESULTS: The p53-/- cells were more resistant than the p53+/+ cells to X-ray irradiation, while the sensitivities of the p53+/+ and p53-/- cells to carbon-ion beam irradiation were comparable. X-ray and carbon-ion beam irradiations predominantly induced apoptosis of the p53+/+ cells but not the p53-/- cells. In the p53-/- cells, carbon-ion beam irradiation, but not X-ray irradiation, markedly induced mitotic catastrophe that was associated with premature mitotic entry with harboring long-retained DSBs at 24 h post-irradiation. CONCLUSIONS: Efficient induction of mitotic catastrophe in apoptosis-resistant p53-deficient cells implies a strong cancer cell-killing effect of carbon-ion beam irradiation that is independent of the p53 status, suggesting its biological advantage over X-ray treatment.

  19. Luminescence dating of Netherlands’ sediments

    OpenAIRE

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we review: 1) the development of the methodology; 2) tests of the reliability of luminescence dating on Netherlands’ sediments; and 3) geological applications of the method in the Netherlands. Our review shows that optically stimulated luminescence dating of quartz grains using the single aliquot regenerative dose method yi...

  20. Radiation on luminescent properties of quartz glasses and fiber light pipes

    CERN Document Server

    Abdurakhmanov, B S; Gulamova, R R; Alimov, R; Yuldashev, B S; Ashurov, M K; Rustamov, I R

    2002-01-01

    Paper contains the results of investigation into X-ray luminescence of KI and KU-1 quartz glasses and of various composition and size quartz fiber light pipes (FLP) gamma-irradiated within 10 sup 2 -10 sup 7 Gy dose range. On the basis of analysis of X-ray luminescence spectra of glasses and FLP and comparison of the experimental data one detected in spectra two luminescence bands within 410, 450-470 nm range. One determined dose dependences of X-ray luminescence intensity of every of these bands of luminescence and hypothesized about the nature of the relevant centers. The protective role of OH-groups in the process of radiation-induced generation of luminescence centres under gamma-irradiation of quartz glasses and FLP was confirmed experimentally

  1. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  2. ON THE BEAM INDUCED QUASI-INSTABILITY TRANSFORMATION OF THE DAMPED APERIODIC MODE IN THE INTERGALACTIC MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Kolberg, U.; Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- and Astrophysik, Ruhr-Universität, Bochum (Germany); Yoon, P. H., E-mail: uk@tp4.rub.de, E-mail: rsch@tp4.rub.de, E-mail: yoonp@umd.edu [IPST, University of Maryland, College Park, Maryland 20742-2431 (United States)

    2016-02-01

    Highly relativistic electron–positron pair beams considerably affect the spontaneously emitted field fluctuations in the unmagnetized intergalactic medium (IGM). In view of the considered small density ratio of beam and background plasma, a perturbative treatment is employed in order to derive the spectral balance equations for the fluctuating fields from first principles of plasma kinetic theory that are covariantly correct within the limits of special relativity. They self-consistently account for the competing effects of spontaneous and induced emission and absorption in the perturbed thermal plasma. It is found that the presence of the beam transforms the growth rate of the dominating transverse damped aperiodic mode into an effective growth rate that displays positive values in certain spectral regions if beam velocity and wave vector are perpendicular or almost perpendicular to each other. This corresponds to a quasi-instability that induces an amplification of the fluctuations for these wavenumbers. Such an effect can greatly influence the cosmic magnetogenesis as it affects the strengths of the spontaneously emitted magnetic seed fields in the IGM, thereby possibly lowering the required growth time and effectivity of any further amplification mechanism such as an astrophysical dynamo.

  3. On the Beam Induced Quasi-instability Transformation of the Damped Aperiodic Mode in the Intergalactic Medium

    Science.gov (United States)

    Kolberg, U.; Schlickeiser, R.; Yoon, P. H.

    2016-02-01

    Highly relativistic electron-positron pair beams considerably affect the spontaneously emitted field fluctuations in the unmagnetized intergalactic medium (IGM). In view of the considered small density ratio of beam and background plasma, a perturbative treatment is employed in order to derive the spectral balance equations for the fluctuating fields from first principles of plasma kinetic theory that are covariantly correct within the limits of special relativity. They self-consistently account for the competing effects of spontaneous and induced emission and absorption in the perturbed thermal plasma. It is found that the presence of the beam transforms the growth rate of the dominating transverse damped aperiodic mode into an effective growth rate that displays positive values in certain spectral regions if beam velocity and wave vector are perpendicular or almost perpendicular to each other. This corresponds to a quasi-instability that induces an amplification of the fluctuations for these wavenumbers. Such an effect can greatly influence the cosmic magnetogenesis as it affects the strengths of the spontaneously emitted magnetic seed fields in the IGM, thereby possibly lowering the required growth time and effectivity of any further amplification mechanism such as an astrophysical dynamo.

  4. Decursin reduce radio-resistance of hypoxic regions under the proton beam therapy by induced HIF-1α degradation

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Myung Hwan; Kim, Kye Ryung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-10-15

    Protons induce cancer-cell apoptosis in vitro and block blood vessel formation in vivo through the generation of reactive oxygen species (ROS). The fact that proton severely inhibits blood vessel development in zebrafish embryos suggests a higher sensitivity of vascular endothelial cells to proton beam. Decursin, a coumarin compound, was originally isolated from Angelica gigas Nakai (Dang Gui). A. gigas root has been traditionally used in Korean folk medicine for the treatment of anemia and other common diseases. In previous reports, decursin was reported to exhibit anti-tumor activity against various cancer cells and to inhibit the activities of the androgen and androgen-receptor (AR) signaling pathway in prostate cancer, induction of cell cycle arrest and apoptosis in various cancer cells, such as prostate, breast, bladder, and colon cancer cells. Decursin also inhibits VEGF-induced angiogenesis through the suppression of the VEGFR-2-signaling pathway. However, the mechanism of decursin mediates change of HIF-1α activities is not clear. In this research, we identified regulations of the HIF-1α and the anti-angiogenesis effects of decursin in proton-beam-irradiated human lung cancer, prostate cancer and Hepatic cancer cells. We investigated the underlying mechanisms of positive effects of protonbeam-induced anti-angiogenesis. Our data indicate that the groups co-treated with decursin and a proton-beam had significant reduced HIF-1α activity compared with the groups treated with only a proton beam under the hypoxic condition caused by DFX(desferrioxamine). Decursin was found to induced HIF-1α degradation. Therefore, we suggest that decursin may be a potential candidate for use as a sensitizer for proton-beaminduced cell apoptosis. Here we have shown that decursin successfully reduced HIF-1α stability under hypoxic condition by induced desferrioxamine. We showed novel candidates for anti-angiogenic compound, decursin, leading to complete inhibition of radio

  5. Novel Mechano-Luminescent Sensors Based on Piezoelectric/Electroluminescent Composites

    Directory of Open Access Journals (Sweden)

    Yunzhang Fang

    2011-04-01

    Full Text Available A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

  6. The role of low-energy electrons in focused electron beam induced deposition: four case studies of representative precursors

    Directory of Open Access Journals (Sweden)

    Rachel M. Thorman

    2015-09-01

    Full Text Available Focused electron beam induced deposition (FEBID is a single-step, direct-write nanofabrication technique capable of writing three-dimensional metal-containing nanoscale structures on surfaces using electron-induced reactions of organometallic precursors. Currently FEBID is, however, limited in resolution due to deposition outside the area of the primary electron beam and in metal purity due to incomplete precursor decomposition. Both limitations are likely in part caused by reactions of precursor molecules with low-energy (3, Pt(PF34, Co(CO3NO, and W(CO6. Through these case studies, it is evident that this combination of studies can provide valuable insight into potential mechanisms governing deposit formation in FEBID. Although further experiments and new approaches are needed, these studies are an important stepping-stone toward better understanding the fundamental physics behind the deposition process and establishing design criteria for optimized FEBID precursors.

  7. Determination of the fission barrier height in fission of heavy radioactive beams induced by the (d,p)-transfer

    CERN Multimedia

    A theoretical framework is described, allowing to determine the fission barrier height using the observed cross sections of fission induced by the (d,p)-transfer with accuracy, which is not achievable in another type of low-energy fission of neutron-deficient nuclei, the $\\beta$-delayed fission. The primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission of...

  8. Luminescence properties of Si-containing porous matrix–PbS nanoparticle systems

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, S. A., E-mail: satarasov@mail.ru; Aleksandrova, O. A.; Lamkin, I. A.; Maksimov, A. I.; Maraeva, E. V.; Mikhailov, I. I.; Moshnikov, V. A. [St. Petersburg State Electrotechnical University “LETI” (Russian Federation); Musikhin, S. F. [St. Petersburg State Polytechnic University (Russian Federation); Nalimova, S. S.; Permyakov, N. V.; Spivak, Yu. M.; Travkin, P. G. [St. Petersburg State Electrotechnical University “LETI” (Russian Federation)

    2015-12-15

    The luminescence properties of systems that contain lead-sulfide nanoparticles deposited onto substrates fabricated from porous silicon, oxidized porous silicon, and porous (tin-oxide)–(silicon-oxide) layers are studied. It is shown that the structure and composition of the matrix induce a strong effect on the luminescence spectra of colloidal quantum dots, defining their emission wavelength.

  9. Controlling the visible luminescence in hydrothermal ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Lem, Laurent L.C.; Phillips, Matthew R.; Ton-That, Cuong, E-mail: Cuong.Ton-That@uts.edu.au

    2014-10-15

    Cathodoluminescence spectra have been measured in hydrothermal and hydrogen-doped ZnO at different excitation densities and temperatures to investigate the emission efficiencies of near-band-edge (NBE), green and yellow luminescence bands. The NBE intensity depends linearly on the electron beam excitation as expected for excitonic recombination character. The intensities of the green and yellow bands are highly dependent not only on the excitation density but also on temperature. At high excitation densities ZnO exhibits dominant green emission at room temperature; the intensity of the green band can be further controlled by doping ZnO with hydrogen, which passivates green luminescence centers. Conversely at small excitation densities (< 0.1 nA) and low temperatures the visible luminescence from ZnO is predominantly yellow due to the abundance of Li in hydrothermal ZnO. The results are explained by differences in the recombination kinetics and the relative concentrations of the green and yellow centers, and illustrate that single-color emission can be achieved in ZnO by adjusting the excitation power and temperature. - Highlights: • Hydrothermal ZnO crystals are analyzed by cathodoluminescence spectroscopy. • Intensities of luminescence bands are highly dependent on excitation density. • Visible luminescence is influenced by temperature and hydrogen dopants. • Emission efficiencies are explained by recombination kinetics of defects.

  10. Influence of solution parameters on europium(III), α-Al2O3, and humic acid interactions: Macroscopic and time-resolved laser-induced luminescence data

    Science.gov (United States)

    Janot, Noémie; Benedetti, Marc F.; Reiller, Pascal E.

    2013-12-01

    Speciation of Eu(III) in the presence of purified Aldrich humic acid (PAHA) and/or α-Al2O3 has been studied by time-resolved luminescence spectroscopy as a function of pH, ionic strength and PAHA concentration. The comparisons of macroscopic and spectroscopic data (adsorption, spectra, and decay times analyses) between the ternary system, i.e., Eu(III)/PAHA/α-Al2O3, and the corresponding binary systems are comprehensively presented. As expected, results show almost no influence of ionic strength on Eu(III) adsorption onto α-Al2O3. However, in the binary Eu(III)/PAHA system, it is clearly shown that variations of electrolyte concentration, which modify PAHA conformation, influence the symmetry of the humic-bound Eu(III) at pH ⩾ 7. In the ternary system, adsorption of both Eu(III) and PAHA onto the surface decreases with ionic strength. At I = 0.01 M NaClO4, Eu(III) luminescence decay is much faster than at I = 0.1 M NaClO4. This is most likely due to the lower surface concentration of PAHA at lower ionic strength, leading to a less constrained environment for Eu(III) ions. At high pH, luminescence spectra are different at the two ionic strengths studied. Concerning the influence of PAHA concentration, spectroscopic results show that in the binary Eu(III)/PAHA system complete complexation of 1 μM Eu(III) is reached for 16 mgPAHA l-1 at pH 4, and for lower PAHA concentrations at higher pH. At the same PAHA concentration, asymmetry ratios are comparable between the binary Eu(III)/PAHA system and the ternary system between pH 4 and 7.7. This means that the presence of mineral surface has almost no influence on Eu(III) environment symmetry below pH 8; hence, under these acid to neutral pH conditions, the occurrence of Eu(III)-bridged humic surface complexes is not likely. In the ternary system, at different pH, luminescence decay times of Eu(III) increase with PAHA concentration. They are much higher in the ternary system than in the binary Eu(III)/PAHA system

  11. New luminescent materials and filters for Luminescent Solar Concentrators

    NARCIS (Netherlands)

    De Boer, D.K.G.; Ronda, C.R.; Keur, W.C.; Meijerink, A.

    2012-01-01

    In a Luminescent Solar Concentrator (LSC), short-wavelength light isconverted by a luminescent material into long-wavelength light, which is guided towards a photovoltaic cell. In principle, an LSC allows for high concentration, but in practice this is prevented by lossmechanisms like limited sunlig

  12. Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

    OpenAIRE

    Onofre, A.; Castro, Nuno Filipe Silva Fernandes; ATLAS Collaboration

    2016-01-01

    This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge a...

  13. Micro-vibrating spatial filters-induced beam positioning stability in large laser system

    Institute of Scientific and Technical Information of China (English)

    Fang Liu; Jianqiang Zhu; Jia Xu; Quanyuan Shan; Kun Xiao; Xuejie Zhang

    2012-01-01

    A dynamic beam propagation model of micro-vibrating spatial filters in inertial confinement fusion (ICF) facilities is built based on the additional beam in SG-Ⅱ facility.The transfer matrix is then deduced,and the sensitivities of the beam positioning to the pellet in the target area to the vibrations of every spatial filter are analyzed,which indicates that the vibrations of spatial filters in the pre-amplify zone has less effects on beam positioning stability at the target.In addition,the vibrations of spatial filters in the main amplify zone dominates the beam positioning stability of the target,especially the vibration of the spatial filter SF7.

  14. Drift-kink instability induced by beam ions in field-reversed configurations

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Kazumi; Horiuchi, Ritoku; Sato, Tetsuya [National Inst. for Fusion Science, Toki, Gifu (Japan)

    1999-04-01

    The drift-kink instability in field-reversed configurations with a beam component is investigated by means of a three-dimensional particle simulation. The unstable mode with the toroidal mode number n=4 grows with the rate {gamma} {approx} 0.1 - 1.0{omega}{sub ci} for a strong beam current and deforms the plasma profile along the beam orbit in the vicinity of the field-null line. This mode is nonlinearly saturated as a result of the relaxation of current profile. Both the saturation level and the growth rate tend to increase as the ratio of the beam current to the plasma current I{sub b}/I{sub p} increases. It is also found that there is a threshold value of the beam velocity {upsilon}{sub b} {approx} {upsilon}{sub Ti} (ion thermal velocity) for the excitation of the instability. (author)

  15. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Hon-Meng [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Bee, Soo-Tueen, E-mail: beest@utar.edu.my [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2014-01-15

    Highlights: • Investigation of trimethylopropane trimethacrylate (TMPTMA) on electron beam irradiated PLA. • Irradiated PLA blends were weakened by incorporation of high amount of TMPTMA. • TMPTMA interacts with polymer free radicals to build crosslinking network. -- Abstract: The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3–5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25–250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

  16. Ion beam induced charge collection (IBICC) from integrated circuit test structures using a 10 MeV carbon microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Guo, B.N.; Bouanani, M.E.; Duggan, J.L.; McDaniel, F.D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, Denton, Texas 76203 (United States); Doyle, B.L.; Walsh, D.S. [Ion Beam Materials Research Laboratory, Sandia National Laboratories, MS 1056, PO Box 5800, Albuquerque, New Mexico 87185 (United States)] Aton, T.J. [Silicon Technology Development, Texas Instruments Inc., PO Box 650311, MS 3704, Dallas, Texas 75265 (United States)

    1999-06-01

    As feature sizes of Integrated Circuits (ICs) continue to shrink, the sensitivity of these devices, particularly SRAMs and DRAMs, to natural radiation is increasing. In this paper, the Ion Beam Induced Charge Collection (IBICC) technique is utilized to simulate neutron-induced Si recoil effects in ICs. The IBICC measurements, conducted at the Sandia National Laboratories, employed a 10 MeV carbon microbeam with 1{mu}m diameter spot to scan test structures on specifically designed ICs. With the aid of IC layout information, an analysis of the charge collection efficiency from different test areas is presented. {copyright} {ital 1999 American Institute of Physics.}

  17. B-site ordered double perovskite LaBa1-xSrxZnSbO6 (0 ≤ x ≤ 1): Sr(2+)-doping-induced symmetry evolution and structure-luminescence correlations.

    Science.gov (United States)

    Jiang, Pengfei; Zhou, Zhengyang; Gao, Wenliang; Cong, Rihong; Yang, Tao

    2016-03-07

    The study of perovskites has been active for a long time. Here, we rationally designed and prepared a double perovskite, LaBaZnSbO6, by selecting Zn(2+) and Sb(5+) with large size and charge differences, and, indeed, complete B-site ordering can be achieved. Careful study using powder X-ray diffraction data pinpointed its space group to be I2/m, which has rarely been seen in double perovskites. Thereafter, an interesting observation of Sr(2+)-doping-induced symmetry evolution from I2/m to P21/n was confirmed in the complete solid solutions LaBa1-xSrxZnSbO6, where the tilting system also transferred from a(-)a(-)c(0) to a(-)a(-)c(+). The transition boundary is around x = 0.4. It can also be visualized by the variation of θ (defined as c/[(a + b)/2]), which is associated with the anisotropic shrinkage of the unit cell lattice and indeed shows a minimum at x = 0.4. Such a successive modulation of both the structural symmetry and the average La/Ba/Sr-O bond distances (revealed by Rietveld refinements) motivated us to study the Eu(3+) luminescence in La0.95Eu0.05Ba1-xSrxZnSbO6. Interestingly, the maximum of charge transfer absorption of Eu(3+) shows a precise changing tendency with the A-O bond distances along with the Sr(2+) doping, clearly revealing the structure-luminescence correlations.

  18. High-purity 3D nano-objects grown by focused-electron-beam induced deposition

    Science.gov (United States)

    Córdoba, Rosa; Sharma, Nidhi; Kölling, Sebastian; Koenraad, Paul M.; Koopmans, Bert

    2016-09-01

    To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ˜50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core-shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices.

  19. Measurement of Production Cross Sections of Neodymium induced by Proton Beam

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Sungchul; Kim, Kwangsoo; Kim, Guinyun [Kyungpook National Univ., Daegu (Korea, Republic of); Song, Taeyung; Lee, Youngouk [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Neodymium (Nd) which is the second most abundant rare earth elements is used as a cryocooler and the permanent magnet. In addition, it can be used as a target material for the production of medically important radioisotopes such as {sup 140}Nd and {sup 149}Pm as well as the research of biomedical filed via positron emission tomography. Thus, the characteristics of radionuclides produced from the Nd for application in various fields are necessary to study. In view of this, the production cross sections of the Nd induced by proton beam were determined by the well-known stacked-foil activation method. The {sup 149}Pm radionuclide in this research was measured using the proton energy of 45 MeV at the KIRAMS. Furthermore, the production cross section of {sup 149}Nd produced from the {sup nat}Nd reaction was also measured to understand the contribution for the production of {sup 149}Pm. Longer-lived {sup 149}Pm (53.08 h) is formed by both direct {sup nat}Nd reaction and the decay of {sup 149}Nd. The production cross sections of {sup 149}Pm and {sup 149}Nd from the present work in {sup nat}Nd reaction are compared with those from the literature and those calculated theoretically by TALYS 1.4 code. The production cross sections of {sup 149}Pm and {sup 149}Nd from the {sup nat}Nd reactions within the proton energies of 5.08 ∼ 44.72 MeV were determined from present work. It was found that the produced data show a good agreement with other measured data. However, it can be seen that there are slight differences in the high energy region. Moreover, in order to obtain the independent production cross sections of radionuclides, the contribution by a parent radionuclide needs to be researched.

  20. Ion-beam-induced modifications in the structural and electrical properties of copper oxide selenite nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Pallavi, E-mail: prana.phy@gmail.com; Chauhan, R.P.

    2015-04-15

    Highlights: •Nanowires were synthesized via template-assisted electrodeposition method. •Copper oxide selenite nanowires were irradiated with 160 MeV, Ni{sup +12} ion beam. •XRD confirmed no change in phase of irradiated nanowires. •Electrical resistivity of nanowires was found to decrease with the ion fluence. -- Abstract: Irradiation with swift heavy ions (SHIs) with energy in the MeV range is a unique tool for engineering the properties of materials. In this context, the objective of the present work is to study the conduction of charge carriers in pre- and post-ion-irradiated semiconducting nanowires. Copper oxide selenite nanowires were synthesized using a template-assisted electrodeposition technique from an aqueous solution of 0.8 M CuSO{sub 4}·5H{sub 2}O and 8 mM SeO{sub 2}. The synthesized nanowires were observed to have a monoclinic structure with linear I–V characteristics (IVC). The effect of irradiation with 160 MeV Ni{sup +12} ions on the properties of the copper oxide selenite nanowires was investigated for fluences varying from 10{sup 11} to 10{sup 13} ions/cm{sup 2}. XRD spectra confirmed no change in the phase of the swift-heavy-ion-irradiated nanowires, but a modification in the orientation of the planes was observed that depended on the ion fluence. The electrical resistivity of the semiconducting nanowires also varied with the ion fluence. Simultaneous irradiation-induced modifications to the electro-chemical potential gradient and the granular properties of the material may have been the origin of the alteration in the structural and electrical properties of the nanowires.

  1. Electron postgrowth irradiation of platinum-containing nanostructures grown by electron-beam-induced deposition from Pt(PF3)4

    NARCIS (Netherlands)

    Botman, A.; Hagen, C.W.; Li, J.; Thiel, B.L.; Dunn, K.A.; Mulders, J.J.L.; Randolph, S.; Toth, M.

    2009-01-01

    The material grown in a scanning electron microscope by electron beam-induced deposition (EBID) using Pt(PF3)4 precursor is shown to be electron beam sensitive. The effects of deposition time and postgrowth electron irradiation on the microstructure and resistivity of the deposits were assessed by t

  2. Environmental TEM Study of Electron Beam Induced Electrochemistry of Pr0.64Ca0.36MnO3 Catalysts for Oxygen Evolution

    DEFF Research Database (Denmark)

    Mildner, Stephanie; Beleggia, Marco; Mierwaldt, Daniel

    2015-01-01

    Environmental transmission electron microscopy (ETEVI) studies offer great potential for gathering atomic scale information on the electronic state of electrodes in contact with reactants. It also poses big challenges due to the impact of the high energy electron beam. In this article, we present...... of beam induced potentials is an important step for future controlled electrochemical experiments in an ETEM....

  3. High energy muon induced radioactive nuclides in nickel plate and its use for 2-D muon-beam image profile

    Energy Technology Data Exchange (ETDEWEB)

    Kurebayashi, Y. [Graduate School of Science and Engineering, Yamagata University, Yamagata 990-8560 (Japan); Sakurai, H., E-mail: sakurail@sci.kj.yamagata-u.ac.jp [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Takahashi, Y. [Graduate School of Science and Engineering, Yamagata University, Yamagata 990-8560 (Japan); Doshita, N. [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Kikuchi, S. [Graduate School of Science and Engineering, Yamagata University, Yamagata 990-8560 (Japan); Tokanai, F. [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Horiuchi, K. [Graduate School of Science and Technology, Hirosaki University, 3, Bunkyo-chou, Hirosaki 036-8561, Aomori (Japan); Tajima, Y. [Institute of Arts and Sciences, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Oe, T. [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Sato, T. [Graduate School of Science and Engineering, Yamagata University, Yamagata 990-8560 (Japan); Gunji, S. [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Inui, E. [Faculty of Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Kondo, K. [Department of Physics, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Iwata, N. [Dept. of Earth and Environmental Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata 990-8560 (Japan); Sasaki, N. [Graduate School of Science and Technology, Hirosaki University, 3, Bunkyo-chou, Hirosaki 036-8561, Aomori (Japan); Matsuzaki, H. [Micro Analysis Laboratory, Tandem accelerator (MALT), The University Museum, The University of Tokyo, 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-0032 (Japan); Kunieda, S. [Nuclear Data Center, Japan Atomic Energy Agency, Tokai-mura, Naka-gun 319-1195, Ibaraki (Japan)

    2015-11-01

    Target materials were exposed to a muon beam with an energy of 160 GeV/c at the COMPASS experiment line in CERN-SPS to measure the production cross-sections for muon-induced radionuclides. A muon imager containing four nickel plates, each measuring 100 mm×100 mm, exposed to the IP plate successfully detected the muon beam image during an irradiation period of 33 days. The contrasting density rate of the nickel plate was (5.2±0.7)×10{sup –9} PSL/muon per one-day exposure to IP. The image measured 122 mm and 174 mm in horizontal and vertical lengths, respectively, in relation to the surface of the base, indicating that 50±6% of the muon beam flux is confined to an area of 18% of the whole muon beam. The number of muons estimated from the PSL value in the total beam image area (0.81±0.1)×10{sup 13} was comparable to the total muon counts of the ion-chamber at the M2 beam line in the CERN-SPS. The production cross-sections of Cr-51, Mn-54, Co-56, Co-57, and Co-58 in nickel were 0.19±0.08, 0.34±0.06, 0.5±0.05, 3.44±0.07, 0.4±0.03 in the unit of mb, respectively, reducing muon associated particles effects. They are approximately 10 times smaller than that a proceeding study by Heisinger et al.

  4. Luminescence dating of Netherland's sediments

    NARCIS (Netherlands)

    Wallinga, J.; Davids, F.; Dijkmans, J.W.A.

    2007-01-01

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments;

  5. Experimental study of electron beam induced removal of H/sub 2/S from geothermal fluids

    Energy Technology Data Exchange (ETDEWEB)

    Helfritch, D.J.; Singhvi, R.; Evans, R.D.; Reynolds, W.E.

    1983-09-01

    The treatment of geothermal steam by electron beam irradiation is a potential alternative method of H/sub 2/S removal which can be applied upstream or downstream and has no chemical requirements. The experimental work reported here examines the effectiveness of electron beam treatment of geothermal fluids. These fluids are produced by combining the constituents in a heated cell, which contains an electron beam transparent window. Irradiation of the contents and subsequent chemical analysis allows an evaluation of effectiveness. These results are used for a commercial feasibility assessment.

  6. Deconvolution of the luminescence and magnetic circularly polarized luminescence spectra of the lowest excited states of Ru(bpy)2 + 3

    Science.gov (United States)

    Krausz, Elmars; Moran, Grainne

    1989-01-01

    The luminescence and magnetic circular polarized luminescence (MCPL) spectra of Ru(bpy)2+3 in poly-(vinyl-alcohol) solid solutions are analyzed in terms of a three level model of the lowest excited states. The individual luminescence and MCPL profiles of the three states are obtained, for the first time, by careful deconvolution of the temperature dependent spectra. The temperature dependence of the MCPL spectra in the 1.5-60 K range can be quite accurately accounted for by the superposition of strong (temperature independent) B terms from each of the states of relative magnitudes ≈4:1:-0.1. A comparison of the very different luminescence and MCPL spectral profiles of the transitions arising from the three individual states provides insights into the unusual and apparently vibronically induced processes dominant in Ru(bpy)2+3 luminescence for all three electronic states.

  7. Luminescent macrocyclic lanthanide complexes

    Science.gov (United States)

    Raymond, Kenneth N [Berkeley, CA; Corneillie, Todd M [Campbell, CA; Xu, Jide [Berkeley, CA

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  8. Stored Luminescence Computed Tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Ge

    2013-01-01

    The phosphor nanoparticles made of doped semiconductors, pre-excited by well-collimated X-ray radiation, were recently reported for their light emission upon NIR light stimulation. The characteristics of X-ray energy storage and NIR stimulated emission is highly desirable to design targeting probes and improve molecular and cellular imaging. Here we propose stored luminescence computed tomography (SLCT), perform realistic numerical simulation, and demonstrate a much-improved spatial resolution in a preclinical research context. The future opportunities are also discussed along this direction.

  9. Simulation of temperature and thermally induced stress of human tooth under CO2 pulsed laser beams using finite element method.

    Science.gov (United States)

    Sabaeian, Mohammad; Shahzadeh, Mohammadreza

    2015-02-01

    The authors report the simulation of temperature distribution and thermally induced stresses of human tooth under CO2 pulsed laser beam. A detailed tooth structure comprising enamel, dentin, and pulp with realistic shapes and thicknesses were considered, and a numerical method of finite element was adopted to solve time-dependent bio-heat and stress equations. The realistic boundary conditions of constant temperature for those parts embedded in the gingiva and heat flux condition for those parts out of the gingiva were applied. The results which were achieved as a function of energy density (J/cm(2)) showed when laser beam is irradiated downward (from the top of the tooth), the temperature and thermal stresses decrease quickly as a function of depth that is a result of strong absorption of CO2 beams by enamel. This effect is so influential that one can use CO2 beams to remove micrometer layers while underlying tissues, especially the pulp, are safe from thermal effects.

  10. Particle manipulation with acoustic vortex beam induced by a brass plate with spiral shape structure

    Science.gov (United States)

    Wang, Tian; Ke, Manzhu; Li, Weiping; Yang, Qian; Qiu, Chunyin; Liu, Zhengyou

    2016-09-01

    In this work, we give direct demonstration of acoustic radiation force and acoustic torque on particles exerted by an acoustic vortex beam, which is realized by an acoustic artificial structure plate instead of traditional transducer arrays. First, the first order acoustic vortex beam, which has the distinctive features of a linear and continuous phase variation from -π to π around its propagation axis and a magnitude null at its core, is obtained through one single acoustic source incident upon a structured brass plate with Archimedean spiral grating engraved on the back surface. Second, annular self-patterning of polystyrene particles with a radius of 90 μm is realized in the gradient field of this acoustic vortex beam. In addition, we further exhibit acoustic angular momentum transfer to an acoustic absorptive matter, which is verified by a millimeter-sized polylactic acid disk self-rotating in water in the acoustic field of the generated vortex beam.

  11. Low energy ion beam induced changes in structural and thermal properties of polycarbonate

    Science.gov (United States)

    Reheem, A. M. Abdel; Atta, A.; Maksoud, M. I. A. Abdel

    2016-10-01

    The aim of the present study is extended for obtaining relation between the collision of ion beam with polycarbonate polymer (PC) and the introduced modification of technological applications. Polycarbonate films are irradiated by a 6 keV argon ion beam extracted from locally design cold cathode ion source with different ion fluences. The films are characterized using X-ray Diffraction (XRD), Mechanical tester, Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The increase in ion beam irradiation leads to an increase in the tensile strength and reduction in elongation at break for PC. TGA Analysis shows that the thermal decomposition temperature of irradiated polycarbonate changes with ion fluence. The DSC graphs show improvements in thermal stability with increase in the activation energy after ion beam irradiation. Ion penetration depths and distributions of scattered atoms are calculated using SRIM Monte Carlo simulation programs.

  12. Pressure-induced Pr{sup 3+} {sup 3}P{sub 0} luminescence in cubic Y{sub 2}O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Alok M. [GE Global Research, One Research Circle, Niskayuna 12309, NY (United States); Renero-Lecuna, Carlos [MALTA CONSOLIDER Team – Dpto. Física Aplicada, Facultad de Ciencias, Universidad de Cantabria, Santander 39005 (Spain); Santamaría-Pérez, David [MALTA CONSOLIDER Team – Dpto. Químico Física, Facultad de Ciencias Químicas, Universidad Complutense Madrid, E-28040 Madrid (Spain); Rodríguez, Fernando [MALTA CONSOLIDER Team – DCITIMAC, Facultad de Ciencias, Universidad de Cantabria, Santander 39005 (Spain); Valiente, Rafael, E-mail: valientr@unican.es [MALTA CONSOLIDER Team – Dpto. Física Aplicada, Facultad de Ciencias, Universidad de Cantabria, Santander 39005 (Spain)

    2014-02-15

    An explanation for the puzzling absence of luminescence from the Pr{sup 3+} {sup 3}P{sub J[=0,1,2]} states in C-Ln{sub 2}O{sub 3} (cubic; Ln{sup 3+}=Lu{sup 3+}, Y{sup 3+}, Gd{sup 3+}) family of materials is provided by conducting a study of the emission properties of C-Y{sub 2}O{sub 3}:Pr{sup 3+} under applied hydrostatic pressure. Above 7 GPa, electronic transitions from the Pr{sup 3+} {sup 3}P{sub J[=0,1,2]} states are observed in the emission spectrum of C-Y{sub 2}O{sub 3}:Pr{sup 3+} at room temperature and below. The experimental data reveal that the crystal-field split Pr{sup 3+} 4f{sup 1}5d{sup 1} configuration is located entirely within the host lattice conduction band and that the promotion of the electron to the Pr{sup 3+} 4f{sup 1}5d{sup 1} state produces a self-trapped exciton-like state with the configuration, [Pr{sup 4+}+e{sub CB}], where e{sub CB} indicates an electron in the host lattice conduction band. Upon excitation, the exciton-like state bypasses the upper emitting {sup 3}P{sub J[=0,1,2]} states and directly feeds the lower emitting {sup 1}D{sub 2} state. This explains the absence of optical transitions from the Pr{sup 3+} {sup 3}P{sub J[=0,1,2]} states in the emission spectrum of C-Y{sub 2}O{sub 3}:Pr{sup 3+} at ambient pressure. At high pressures, emission transitions from the Pr{sup 3+} {sup 3}P{sub J[=0,1,2]} states are observed because of the localization of the Pr{sup 3+} 4f{sup 1}5d{sup 1} state to below the host lattice conduction band edge. -- Highlights: • Explanation for the complete absence of luminescence from the Pr{sup 3+} {sup 3}P{sub J} state in cubic Ln{sub 2}O{sub 3} sesquioxides. • By high pressure experiments, we have associated the absence of Pr{sup 3+} {sup 3}P{sub J} emission to the presence of an exciton state • The exciton state bypasses the upper emitting {sup 3}P{sub J} states and directly feeds the lower emitting {sup 1}D{sub 2} state. • Apart from the fundamental interest, this finding is relevantly

  13. Velocity distribution measurements in atomic beams generated using laser induced back-ablation

    CERN Document Server

    Denning, A; Lee, S; Ammonson, M; Bergeson, S D

    2008-01-01

    We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

  14. Beam-loss-induced electrical stress test on CMS Silicon Strip Modules

    CERN Document Server

    Fahrer, M; Hartmann, F; Heier, S; MacPherson, A; Muller, T H; Weiler, T h

    2004-01-01

    Based on simulated LHC beam loss scenarios, fully depleted CMS silicon tracker modules and sensors were exposed to 42 ns-long beam spills of approximately 10**1**1 protons per spill at the PS at CERN. The ionisation dose was sufficient to short circuit the silicon sensors. The dynamic behaviour of bias voltage, leakage currents and voltages over coupling capacitors were monitored during the impact. Results of pre- and post-qualification as well as the dynamic behaviour are shown.

  15. A compact micro-beam system using a tapered glass capillary for proton-induced X-ray radiography

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Jun [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)], E-mail: jhasegaw@nr.titech.ac.jp; Shiba, Shigeki; Fukuda, Hitoshi; Oguri, Yoshiyuki [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

    2008-05-15

    A compact micro-beam system, containing a tapered glass capillary tube with a tip diameter on the order of 10 {mu}m, was constructed to examine the applicability of capillary-generated micro-beams to high-contrast radiography based on proton-induced quasi-monochromatic X-rays. The transport efficiency of swift protons (2-3 MeV) through the capillary was examined as a function of the capillary tilt angle and the capillary tip diameter. We obtained transport efficiencies of approximately three times larger than would be expected from the geometrical shape of the capillary. This enhancement indicates that a focusing effect occurred in the capillary. A metallic thin foil was irradiated with the micro-beam and quasi-monochromatic X-rays were produced. By calculating the X-ray yields induced by proton bombardment in the foil and comparing them with the X-ray counts observed at the detector, the throughput efficiency of the X-ray imaging system was evaluated. We demonstrated magnification radiography of a small object to show that a spatial resolution on the order of 10 {mu}m was achievable in our system.

  16. The nature of unusual luminescence in natural calcite, CaCO3

    Energy Technology Data Exchange (ETDEWEB)

    Gaft, M.; Nagli, L.; Panczer, G.; Waychunas, G.; Porat, N.

    2008-11-01

    The unusual luminescence of particular varieties of natural pink calcite (CaCO{sub 3}) samples was studied by laser-induced time-resolved luminescence spectroscopy at different temperatures. The luminescence is characterized by intense blue emission under short-wave UV lamp excitation with an extremely long decay time, accompanied by pink-orange luminescence under long wave UV excitation. Our investigation included optical absorption, natural thermostimulated luminescence (NTL) and Laser-Induced Breakdown Spectroscopy (LIBS) studies. Two luminescence centers were detected: a narrow violet band, with {lambda}{sub max} = 412 nm, {Delta} = 45 nm, two decay components of {tau}{sub 1} = 5 ns and {tau}{sub 2} = 7.2 ms, accompanied by very long afterglow, and an orange emission band with {lambda}{sub max} = 595 nm, {Delta} = 90 nm and {tau} = 5 ns. Both luminescence centers are thermally unstable with the blue emission disappearing after heating at 500 C, and the orange emission disappearing after heating at different temperatures starting from 230 C, although sometimes it is stable up to 500 C in different samples. Both centers have spectral-kinetic properties very unusual for mineral luminescence, which in combination with extremely low impurity concentrations, prevent their identification with specific impurity related emission. The most likely explanation of these observations may be the presence of radiation-induced luminescence centers. The long violet afterglow is evidently connected with trapped charge carrier liberation, with their subsequent migration through the valence band and ultimate recombination with a radiation-induced center responsible for the unusual violet luminescence.

  17. Oxygen partial pressure induced effects on the microstructure and the luminescence properties of pulsed laser deposited TiO2 thin films

    Directory of Open Access Journals (Sweden)

    A. K. Kunti

    2017-01-01

    Full Text Available In this work, the influence of oxygen partial pressure on structural, morphological, and optical properties of TiO2 thin films grown on fused quartz substrate at different oxygen partial pressure by pulsed laser deposition were examined. X-Ray diffraction (XRD patterns show the formation of TiO2 anatase phase deposited at high oxygen pressure. Atomic Force Microscopy (AFM reveals that surface roughness of the films increases with oxygen pressure. Variation of surface morphology of films with increasing oxygen partial pressure was studied by AFM. It is observed that energy band gap of the films increases from 3.27 eV to 3.52 eV with the increase of oxygen pressure and is attributed to the decrease of oxygen defects. TiO2 thin films exhibited blue emission under the excitation of 320 nm wavelength. De-convoluted photoluminescence (PL peaks showed that defect states are responsible for visible emission in TiO2 thin films. The intensity of PL emission associated with oxygen vacancies decreases with increasing oxygen pressure. Photometric characteristic analysis shows that the films deposited 1x10-4 mbar oxygen pressure exhibited intense blue emission with high luminescence efficacy of radiation.

  18. Electron-Beam-Induced Antiphase Boundary Reconstructions in a ZrO2-LSMO Pillar-Matrix System.

    Science.gov (United States)

    Zhou, Dan; Sigle, Wilfried; Kelsch, Marion; Habermeier, Hanns-Ulrich; van Aken, Peter A

    2016-09-14

    The availability of aberration correctors for the probe-forming lenses makes simultaneous modification and characterization of materials down to atomic scale inside a transmission electron microscopy (TEM) realizable. In this work, we report on the electron-beam-induced reconstructions of three types of antiphase boundaries (APBs) in a probe-aberration-corrected TEM. With the utilization of high-angle annular dark-field scanning transmission electron microscopy (STEM), annular bright-field STEM, and electron energy-loss spectroscopy, the motion of both heavy element Mn and light element O atomic columns under moderate electron beam irradiation are revealed at atomic resolution. Besides, Mn segregated in the APBs was observed to have reduced valence states which can be directly correlated with oxygen loss. Charge states of the APBs are finally discussed on the basis of these experimental results. This study provides support for the design of radiation-engineering solid-oxide fuel cell materials.

  19. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Science.gov (United States)

    Marcak, Adrian; Corbella, Carles; de los Arcos, Teresa; von Keudell, Achim

    2015-10-01

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  20. Note: Ion-induced secondary electron emission from oxidized metal surfaces measured in a particle beam reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marcak, Adrian; Corbella, Carles, E-mail: carles.corbella@rub.de; Keudell, Achim von [Research Group Reactive Plasmas, Ruhr-University Bochum, 44801 Bochum (Germany); Arcos, Teresa de los [Technical and Macromolecular Chemistry, Paderborn University, 33098 Paderborn (Germany)

    2015-10-15

    The secondary electron emission of metals induced by slow ions is characterized in a beam chamber by means of two coaxial semi-cylindrical electrodes with different apertures. The voltages of the outer electrode (screening), inner electrode (collector), and sample holder (target) were set independently in order to measure the effective yield of potential and kinetic electron emissions during ion bombardment. Aluminum samples were exposed to quantified beams of argon ions up to 2000 eV and to oxygen atoms and molecules in order to mimic the plasma-surface interactions on metallic targets during reactive sputtering. The variation of electron emission yield was correlated to the ion energy and to the oxidation state of Al surfaces. This system provides reliable measurements of the electron yields in real time and is of great utility to explore the fundamental surface processes during target poisoning occurring in reactive magnetron sputtering applications.

  1. High-resolution electron-beam-induced-current study of the defect structure in GaN epilayers

    CERN Document Server

    Shmidt, N M; Usikov, A S; Yakimov, E B; Zavarin, E E

    2002-01-01

    Electron-beam-induced-current (EBIC) investigations of GaN structures grown by metal-organic chemical vapour deposition on (0001) sapphire substrates have been carried out. It is shown that the widths of the EBIC profiles for individual extended defects can be as small as about 100 nm. This width is observed to decrease with decreasing diffusion length and/or with increasing electron beam energy. The high spatial resolution is explained by the small diffusion length in the samples under study. The diffusion length is small even in structures with dislocation densities of about 10 sup 8 cm sup - sup 3 and carrier mobilities of about 600 cm sup 2 V sup - sup 1 s sup - sup 1 at 300 K and 1800 cm sup 2 V sup - sup 1 s sup - sup 1 at 125 K.

  2. Reaction dynamics induced by the radioactive ion beam {sup 7}Be on medium-mass and heavy targets

    Energy Technology Data Exchange (ETDEWEB)

    Mazzocco, M., E-mail: marco.mazzocco@pd.infn.it; Stefanini, C.; Strano, E.; Torresi, D.; Lay, J. A.; Molini, P.; Soramel, F. [Dipartimento di Fisica e Astronomia, Università di Padova, via F. Marzolo 8, I-35131 Padova (Italy); INFN-Sezione di Padova, via F. Marzolo 8, I-35131 Padova (Italy); Boiano, A.; Parascandolo, C.; Pierroutsakou, D.; Di Meo, P. [INFN-Sezione di Napoli, via Cintia, I-80126, Napoli (Italy); Boiano, C. [INFN-Sezione di Milano, via Celoria 16, I-20133, Napoli (Italy); La Commara, M.; Sandoli, M.; Silvestri, R. [INFN-Sezione di Napoli, via Cintia, I-80126, Napoli (Italy); Dipartimento di Fisica, Università di Napoli “Federico II”, via Cintia, I-80126, Napoli (Italy); Manea, C.; Nicoletto, M. [INFN-Sezione di Padova, via F. Marzolo 8, I-35131 Padova (Italy); Acosta, L. [Departamento de Fìsica Aplicada, Universidad de Huelva, Campus de El Carmen, E-21071 Huelva (Spain); INFN-Sezione di Catania, via Santa Sofia 64, I-95123, Catania (Italy); Fernandez-Garcia, J. P. [INFN-Sezione di Catania, via Santa Sofia 64, I-95123, Catania (Italy); Glodariu, T. [National Institute for Physics and Nuclear Engineering (NIPNE), 30 Reactorului St., 077125 Magurele (Romania); and others

    2015-10-15

    We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam {sup 7}Be (S{sub α} = 1.586 MeV) on medium-mass ({sup 58}Ni) and heavy ({sup 208}Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×10{sup 5} pps {sup 7}Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems.

  3. Beam Induced Ferrite Heating of the LHC Injection Kickers and Proposals for Improved Cooling

    CERN Document Server

    Barnes, M J; Calatroni, S; Day, H; Ducimetière, L; Garlaschè, M; Gomes Namora, V; Mertens, V; Sobiech, Z; Taborelli, M; Uythoven, J; Weterings, W

    2013-01-01

    The two LHC injection kicker systems produce an integrated field strength of 1.3 T·m with a flattop duration variable up to 7860 ns, and rise and fall times of less than 900 ns and 3000 ns, respectively. A beam screen is placed in the aperture of each magnet, which consists of a ceramic tube with conductors in the inner wall. The conductors provide a path for the beam image current and screen the ferrite yoke against wakefields. Recent LHC operation, with high intensity beam stable for many hours, resulted in significant heating of both the ferrite yoke and beam impedance reduction ferrites. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the ferrite yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. Thermal measurement data has been analysed, a thermal model developed and emissivity measurements carried out. Various measures to improve the ferrite cooling have...

  4. Crack-induced debonding failure in fiber reinforced plastics (FRP) strengthened concrete beams: Experimental and theoretical analysis

    Science.gov (United States)

    Pan, Jinlong

    External bonding of FRP plates to the tension substrate of RC beams has been accepted as an efficient and effective technique for flexural strengthening. In this thesis, different problems related to crack-induced debonding of the FRP plate in the flexural strengthened concrete beams have been investigated. FRP strengthened RC beam may fail by FRP debonding from the bottom of a major flexural crack in the span. This kind of failure is studied with the direct shear test in the present research work. Our experimental investigation focuses on the effect of concrete composition on the bond behavior between FRP and concrete. Based on the test results, the bond capacity of the specimen is found to be governed by the concrete surface tensile strength, aggregate size and aggregate content. Then, the neural network is employed to derive an empirical expression for the interfacial fracture energy in terms of concrete surface tensile strength and aggregate content. Using the empirical equation, simulated bond capacity is in good agreement with experimental results. In the FRP strengthened RC beams, debonding of the FRP plate often occurs under the presence of multiple cracks along the span. In the present thesis, experimental and theoretical investigations are performed to study the effect of multiple secondary cracks on the debonding behavior and ultimate load capacity. A new analytical model for FRP debonding under multiple cracks has been developed. The effect of the multiple secondary cracks on the shear softening in the debonded zone is explicitly considered in the model. Using the new model, the simulated values of ultimate load when debonding occurs are in good agreement with measured values. In the FRP strengthened RC beams, concrete cover separation or plate end debonding can be avoided by applying tapers at the FRP plate end. In this situation, it is easier for FRP debonding to be induced by a major flexural crack close to the support. To study the effect of the

  5. Luminescence decay of porous silicon

    Science.gov (United States)

    Chen, X.; Uttamchandani, D.; Sander, D.; O'Donnell, K. P.

    1993-04-01

    The luminescence decay pattern of porous silicon samples prepared by electrochemical etching is characterised experimentally by a non-exponential profile, a strong dependence on temperature and an absence of spectral diffusion. We describe this luminescence as carrier-dopping-assisted recombination. Following the correlation function approach to non-dispersive transport developed by Scher and co-workers [Physics Today 41 (1991) 26], we suggest a simple derivation of analytical functions which accurately describes the anomalous luminescence decay of porous silicon, and show that this model includes exponential and Kohlrausch [Pogg. Ann. Phys. 119 (1863) 352] (stretched-exponential) relaxations as special cases.

  6. Ordered SrTiO3 Nanoripples Induced by Fo cused Ion Beam

    Institute of Scientific and Technical Information of China (English)

    Jiang Wu; Gang Chen; Zhaoquan Zeng; Shibin Li; Xingliang Xu; Zhiming M Wang; Gregory J Salamo

    2012-01-01

    Ordered nanoripples on the niobium-doped SrTiO3 surfaces were fabricated through focused ion beam bombardment. The surface morphology of the SrTiO3 nanoripples was characterized using in situ focused ion beam/scanning electron microscopy. The well-aligned SrTiO3 nanostructures were obtained under optimized ion irradiation conditions. The characteristic wavelength was measured as about 210 nm for different ion beam currents. The relationship between the ion irradiation time and current and SrTiO3 surface morphology was analyzed. The presented method will be an effective supplement for fabrication of SrTiO3 nanostructures that can be used for ferroelectric and electronic applications.

  7. Phase-transition oscillations induced by a strongly focused laser beam

    Science.gov (United States)

    Devailly, Clémence; Crauste-Thibierge, Caroline; Petrosyan, Artyom; Ciliberto, Sergio

    2015-11-01

    We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at Tc=306.6 K and volume fraction ϕc=12.8 % [Crauste et al., arXiv:1310.6720, 2013]. We describe the dynamical properties of the oscillations, which are produced by a competition between various effects: the local accumulation of PMMA produced by the laser beam, thermophoresis, and nonlinear diffusion. We show that the main properties of this kind of oscillations can be reproduced in the Landau theory for a binary mixture in which a local driving mechanism, simulating the laser beam, is introduced.

  8. Luminescent and Non-Luminescent Solar Concentrators: Challenges andd Progress

    NARCIS (Netherlands)

    De Boer, D.K.G.

    2012-01-01

    Luminescent concentrators would allow for high concentration if losses by reabsorption and escape could be minimized. We present new phosphors and filters that facilitate this. Another type of lightguide-based concentrators, diffraction-based, is discussed as well.

  9. Temperature lags of luminescence measurements in a commercial luminescence reader

    Energy Technology Data Exchange (ETDEWEB)

    Kitis, George [Aristotle University of Thessaloniki, Nuclear Physics Laboratory, 54124 Thessaloniki (Greece); Kiyak, Nafiye G. [ISIK University, Faculty of Science and Arts, Physics Department, Sile, 34980 Istanbul (Turkey); Polymeris, George S., E-mail: gspolymeris@ankara.edu.tr [Ankara University, Institute of Nuclear Sciences, Beşevler, 06100 Ankara (Turkey)

    2015-09-15

    The temperature recorded in thermoluminescence and optically stimulated luminescence equipments is not the temperature of the sample but that of the heating element on which the thermocouple is attached. Depending upon the rate of heating, a temperature difference appears between the samples and the heating element, termed as temperature lag, which could have serious effects on the curve shapes and trapping parameters. In the present work the temperature lag effect is studied in a newly developed luminescence equipment measuring both thermoluminescence and optically stimulated luminescence. It is found that the temperature lag could be large for heating rates above 2 K/s and it is strongly dependent upon the sample holder. A simple approximation method is proposed in order to both predict as well as correct for temperature lag effects in luminescence measurements.

  10. Non-rigid image registration to reduce beam-induced blurring of cryo-electron microscopy images

    Energy Technology Data Exchange (ETDEWEB)

    Karimi Nejadasl, Fatemeh; Karuppasamy, Manikandan [Leiden University Medical Center, PO Box 9600, 2300RC Leiden (Netherlands); Newman, Emily R.; McGeehan, John E. [University of Portsmouth, Portsmouth PO1 2DY (United Kingdom); Ravelli, Raimond B. G., E-mail: raimond.nl@gmail.com [Leiden University Medical Center, PO Box 9600, 2300RC Leiden (Netherlands)

    2013-01-01

    Cryo-electron microscopy images of vitrified large macromolecular complexes can become blurred due to beam-induced specimen alterations. Exposure series are examined, and rigid and non-rigid image registration schemes are applied to reduce such blurring. The typical dose used to record cryo-electron microscopy images from vitrified biological specimens is so high that radiation-induced structural alterations are bound to occur during data acquisition. Integration of all scattered electrons into one image can lead to significant blurring, particularly if the data are collected from an unsupported thin layer of ice suspended over the holes of a support film. Here, the dose has been fractioned and exposure series have been acquired in order to study beam-induced specimen movements under low dose conditions, prior to bubbling. Gold particles were added to the protein sample as fiducial markers. These were automatically localized and tracked throughout the exposure series and showed correlated motions within small patches, with larger amplitudes of motion vectors at the start of a series compared with the end of each series. A non-rigid scheme was used to register all images within each exposure series, using natural neighbor interpolation with the gold particles as anchor points. The procedure increases the contrast and resolution of the examined macromolecules.

  11. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    Science.gov (United States)

    Ng, Hon-Meng; Bee, Soo-Tueen; Ratnam, C. T.; Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting; Rahmat, A. R.

    2014-01-01

    The purpose of this research was to investigate the effects of various loading levels of trimethylopropane trimethacrylate (TMPTMA) on the properties of polylactic acid (PLA) cross-linked via electron-beam irradiation. PLA was compounded with 3-5 wt.% of TMPTMA to induce cross-linking upon subjection to electron-beam irradiation doses of 25-250 kGy. The physical properties of the PLA samples were characterised by means of X-ray diffraction, gel fraction and scanning electron microscopy analyses on fractured surfaces after tensile tests. The presence of TMPTMA in PLA was found to effectively increase the crystallite size and gel fraction. However, higher loading levels of TMPTMA could compromise the properties of the PLA/TMPTMA samples, indicating that a larger amount of monomer free radicals might promote degradation within the substantially cross-linked amorphous phase. Irradiation-induced cross-linking in the samples could improve the cross-linking density while decreasing the elongation and interfering with the crystallisation. These effects are caused by the intensive irradiation-induced chain scission that is responsible for the deterioration of the mechanical and crystalline properties of the samples.

  12. Modeling of the intermolecular Force-Induced Adhesion in Freestanding Nanostructures Made of Nano-beams

    Directory of Open Access Journals (Sweden)

    Alireza Yekrangi

    2015-11-01

    Full Text Available Among the intermolecular interactions, the Casimir and van der Waals forces are the most important forces that highly affect the behavior of nanostructures. This paper studies the effect of such forces on the adhesion of cantilever freestanding nanostructures. The nanostructures are made of a freestanding nano-beam which is suspended between two upper and lower conductive surfaces. The linear spring model is applied to derive the elastic force. The Lumped Parameter Model (LPM is used to obtain constitutive equations of the systems. The maximum length of the nano-beam which prevents the adhesion is computed. Results of this study are useful for design and development of miniature devices.

  13. Studies of Beam Induced Electron Cloud Resonances in Dipole Magnetic Fields

    CERN Document Server

    Calvey, J R; Makita, J; Venturini, M

    2016-01-01

    The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring (CESR). These measurements are supported by both analytical models and computer simulations.

  14. Energy dependence measurement of small-type optically stimulated luminescence (OSL) dosimeter by means of characteristic X-rays induced with general diagnostic X-ray equipment.

    Science.gov (United States)

    Takegami, Kazuki; Hayashi, Hiroaki; Okino, Hiroki; Kimoto, Natsumi; Maehata, Itsumi; Kanazawa, Yuki; Okazaki, Tohru; Hashizume, Takuya; Kobayashi, Ikuo

    2016-01-01

    For X-ray inspections by way of general X-ray equipment, it is important to measure an entrance-skin dose. Recently, a small optically stimulated luminescence (OSL) dosimeter was made commercially available by Landauer, Inc. The dosimeter does not interfere with the medical images; therefore, it is expected to be a convenient detector for measuring personal exposure doses. In an actual clinical situation, it is assumed that X-rays of different energies will be detected by a dosimeter. For evaluation of the exposure dose measured by a dosimeter, it is necessary to know the energy dependence of the dosimeter. Our aim in this study was to measure the energy dependence of the OSL dosimeter experimentally in the diagnostic X-ray region. Metal samples weighing several grams were irradiated and, in this way, characteristic X-rays having energies ranging from 8 to 85 keV were generated. Using these mono-energetic X-rays, the dosimeter was irradiated. Simultaneously, the fluence of the X-rays was determined with a CdTe detector. The energy-dependent efficiency of the dosimeter was derived from the measured value of the dosimeter and the fluence. Moreover, the energy-dependent efficiency was calculated by Monte-Carlo simulation. The efficiency obtained in the experiment was in good agreement with that of the simulation. In conclusion, our proposed method, in which characteristic X-rays are used, is valuable for measurement of the energy dependence of a small OSL dosimeter in the diagnostic X-ray region.

  15. Luminescent hyperbolic metasurfaces

    Science.gov (United States)

    Smalley, J. S. T.; Vallini, F.; Montoya, S. A.; Ferrari, L.; Shahin, S.; Riley, C. T.; Kanté, B.; Fullerton, E. E.; Liu, Z.; Fainman, Y.

    2017-01-01

    When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells.

  16. Nanoscale Soldering of Positioned Carbon Nanotubes using Highly Conductive Electron Beam Induced Gold Deposition

    DEFF Research Database (Denmark)

    Madsen, Dorte Nørgaard; Mølhave, Kristian; Mateiu, Ramona Valentina

    2003-01-01

    We have developed an in-situ method for controlled positioning of carbon nanotubes followed by highly conductive contacting of the nanotubes, using electron beam assisted deposition of gold. The positioning and soldering process takes place inside an Environmental Scanning Electron Microscope (E...

  17. Interpretation of electron beam induced charging of oxide layers in a transistor studied using electron holography

    DEFF Research Database (Denmark)

    Ubaldi, F; Pozzi, G; Kasama, Takeshi;

    2010-01-01

    Off-axis electron holography has been used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope using focused ion beam milling. In reconstructed phase images, regions of silicon oxide that are located...

  18. Simulation-aided investigation of beam hardening induced errors in CT dimensional metrology

    DEFF Research Database (Denmark)

    Tan, Ye; Kiekens, Kim; Welkenhuyzen, Frank

    2013-01-01

    Industrial X-ray CT systems are increasingly used as dimensional measuring machines. However, micron level accuracy is not always achievable yet. The measurement accuracy is influenced by many factors, such as workpiece properties, X-ray settings, beam hardening and calibration methods [1-4]. Since...

  19. Electron-beam-induced deformations of SiO2 nanostructures

    NARCIS (Netherlands)

    Storm, A.J.; Chen, J.H.; Ling, X.S.; Zandbergen, H.W.; Dekker, C.

    2005-01-01

    The imaging beam of a transmission electron microscope can be used to fine tune critical dimensions in silicon oxide nanostructures. This technique is particularly useful for the fabrication of nanopores with single-nanometer precision, down to 2 nm. We report a detailed study on the effect of elect

  20. Wavefront-sensor-induced beam size error: physical mechanism, sensitivity-analysis and correction method

    NARCIS (Netherlands)

    Koek, W.D.; Zwet, E.J. van

    2015-01-01

    When using a commonly-used quadri-wave lateral shearing interferometer wavefront sensor (QWLSI WFS) for beam size measurements on a high power CO2 laser, artefacts have been observed in the measured irradiance distribution. The grating in the QWLSI WFS not only generates the diffracted first orders

  1. Requirements for sulfur in cell density-independent induction of luminescence in Vibrio fischeri under nutrient-starved conditions.

    Science.gov (United States)

    Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

    2012-04-01

    Despite the universal requirement for sulfur in living organisms, it is not known whether the luminescence of Vibrio fischeri is sulfur-dependent and how sulfur affects the intensity of its luminescence. In this study, we investigated the requirement for sulfur in V. fischeri luminescence under nutrient-starved conditions. Full induction of V. fischeri luminescence required MgSO(4); in artificial seawater cultures that lacked sufficient MgSO(4), its luminescence was not fully induced. This induction of luminescence was not dependent on autoinduction because the cell density of V. fischeri did not reach the critical threshold concentration. In addition to MgSO(4), this cell density-independent luminescence was induced or maintained by nontoxic concentrations of l-cysteine, sulfate, sulfite, and thiosulfate. Moreover, the addition of N -3-oxo-hexanoyl homoserine lactone and N -octanoyl homoserine lactone, which are known autoinducers in V. fischeri, did not induce luminescence under these conditions. This result suggested that the underlying mechanism of luminescence may be different from the known autoinduction mechanism.

  2. Lanthanide-based luminescence biolabelling.

    Science.gov (United States)

    Sy, Mohamadou; Nonat, Aline; Hildebrandt, Niko; Charbonnière, Loïc J

    2016-04-14

    Luminescent lanthanide complexes display unrivalled spectroscopic properties, which place them in a special category in the luminescent toolbox. Their long-lived line-like emission spectra are the cornerstones of numerous analytical applications ranging from ultrasensitive homogeneous fluoroimmunoassays to the study of molecular interactions in living cells with multiplexed microscopy. However, achieving such minor miracles is a result of years of synthetic efforts and spectroscopic studies to understand and gather all the necessary requirements for the labels to be efficient. This feature article intends to survey these criteria and to discuss some of the most important examples reported in the literature, before explaining in detail some of the applications of luminescent lanthanide labels to bioanalysis and luminescence microscopy. Finally, the emphasis will be put on some recent applications that hold great potential for future biosensing.

  3. Assessment of electron beam-induced abnormal development and DNA damage in Spodoptera litura (F.) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    Yun, Seung-Hwan; Lee, Seon-Woo; Koo, Hyun-Na; Kim, Gil-Hah

    2014-03-01

    The armyworm, Spodoptera litura (F.) is a polyphagous and important agricultural pest worldwide. In this study, we examined the effect of electron beam irradiation on developmental stages, reproduction, and DNA damage of S. litura. Eggs (0-24 h old), larvae (3rd instar), pupae (3 days old after pupation), and adults (24 h after emergence) were irradiated with electron beam irradiation of six levels between 30 and 250 Gy. When eggs were irradiated with 100 Gy, egg hatching was completely inhibited. When the larvae were irradiated, the larval period was significantly delayed, depending on the doses applied. At 150 Gy, the fecundity of adults that developed from irradiated pupae was entirely inhibited. However, electron beam irradiation did not induce the instantaneous death of S. litura adults. Reciprocal crosses between irradiated and unirradiated moths demonstrated that females were more radiosensitive than males. We also conducted the comet assay immediately after irradiation and over the following 5 days period. Severe DNA fragmentation in S. litura cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. However, at more than 100 Gy, DNA damage was not fully recovered.

  4. Quantitative comparison of suitability of various beams for range monitoring with induced beta+ activity in hadron therapy.

    Science.gov (United States)

    Inaniwa, Taku; Tomitani, Takehiro; Kohno, Toshiyuki; Kanai, Tatsuaki

    2005-03-21

    In radiation therapy with hadron beams, it is important to evaluate the range of incident ions and the deposited dose distribution in a patient body for the effective utilization of such properties as the dose concentration and the biological effect around the Bragg peak. However, there is some ambiguity in determining this range because of a conversion error from the x-ray CT number to the charged particle range. This is because the CT number is related to x-ray absorption coefficients, while the ion range is determined by the electron density of the substance. Using positron emitters produced in the patient body through fragmentation reactions during the irradiation has been proposed to overcome this problem. The activity distribution in the patient body can be deduced by detecting pairs of annihilation gamma rays emitted from the positron emitters, and information about the range of incident ions can be obtained. In this paper, we propose a quantitative comparison method to evaluate the mean range of incident ions and monitor the activity distribution related to the deposited dose distribution. The effectiveness of the method was demonstrated by evaluating the range of incident ions using the maximum likelihood estimation (MLE) method and Fisher's information was calculated under realistic conditions for irradiations with several kinds of ions. From the calculated Fisher's information, we compared the relative advantages of initial beams to determine the range of incident ions. The (16)O irradiation gave the most information among the stable heavy ions when we measured the induced activity for 500 s and 60 s just after the irradiation. Therefore, under these conditions, we concluded that the (16)O beam was the optimum beam to monitor the activity distribution and to evaluate the range. On the other hand, if the positron emitters were injected directly as a therapeutic beam, the (15)O irradiation gave the most information. Although the relative advantages of

  5. Mn2+induced luminescence regulation and enhancement of Lu-based nanocrystals%锰离子对镥基纳米晶体的荧光调控与增强

    Institute of Scientific and Technical Information of China (English)

    何恩节; 郑海荣; 高伟; 鹿盈; 李俊娜; 魏映; 王灯; 朱刚强

    2013-01-01

    Transformation from Lu-based nanocrystals in hexagonal and cubic mixed phases to pure cubic phase was observed through adjusting the doping concentration of Mn2+. The mechanism for the phase transformation was discussed in detail. Studies on the time and frequency domain spectra indicated that the semi-pure red emissions in cubic Na5Lu9F32: 40%Mn2+, 20%Yb3+, 2%Ln3+(Ln=Er3+, Ho3+) nanocrystals were caused by a two-step energy transfer between Mn2+and Ln3+ions. After incorporating of Mn2+ions into the host lattices, the local symmetry around the luminescent ion was reduced, which induced the increase of radiative rates for transitions that were mainly contributed by electric dipole radiations. Considerable enhancements in upconversion and downconversion luminescence were accompanied. The result of the current study has great application potential in bioimaging and solar cells.%通过调控Mn2+的掺杂浓度,在镥基纳米晶体成功地实现了六方、四方混合相到纯四方相的相位转变,并详细讨论了其相变机理。时域和频域光谱的分析表明,立方相Na5Lu9F32:40%Mn2+,20%Yb3+,2%Ln3+(Ln=Er3+, Ho3+)纳米晶体内的准纯红色荧光发射主要由Mn2+和Ln3+之间的两步能量转移引起。 Mn2+掺杂后引起了发光离子附近局域对称性的降低,使得电偶极跃迁的辐射速率明显增加,进而导致了上转换、下转换荧光的极大增强。该研究结果在生物荧光成像、太阳能电池效率的提高方面具备潜在的、广阔的应用前景。

  6. Confocal luminescence microscopy study of defect-domain wall interaction in lithium niobate and its application to light-induced domain engineering

    Science.gov (United States)

    Sandmann, Christian

    Understanding the mutual interaction of extrinsic and intrinsic defects with the ferroelectric domain walls of LiNbO3 is the key to achieve domain patterns on the sub-micron scale. For that reason the influence of domain inversion on the Er3+ defect was investigated in a detailed study, in which energetic shifts and changes in the intensity ratio of individual Er3+ sites were found. The results led to an improved model describing the Er3+ defect in LiNbO3 and to the introduction of a concept of an atomistic probe. This atomistic probe allows the determination of the orientation of the ferroelectric axis by means of optical spectroscopy and allows three-dimensional imaging of domain structures with high spatial resolution without topographic artifacts. For this purpose a confocal luminescence microscope was developed, adapted to allow investigation at low temperature and applied electric fields. Based on the concept of an atomistic probe, the interaction of Er and Ti dopants was investigated, and significant spectral broadening and line shifting were found. Calibrating these changes to the [Ti4+]-concentration allows imaging of [Ti4+]-profiles, as found in integrated optical devices. The [Ti4+]-concentration profile can be imaged without artifacts caused by topology, intensity fluctuations, or variations in the [Er3+]-concentration profile. A novel approach was introduced for directly writing ferroelectric domain patterns into LiNbO3 substrates using the confocal microscope to focus visible light from an argon ion laser to a diffraction limited spot. It was shown that space charge fields, created by light with a wavelength of 488nm, can reduce the external applied field needed for domain inversion by up to 30%. So far, structures with a period down to 8mum have been demonstrated. In-situ experiments during domain inversion demonstrated the possibility to monitor the domain inversion process in-situ with a temporal resolution of up to t = 7ms. It could be

  7. In-air broad beam ionoluminescence microscopy as a tool for rocks and stone artworks characterisation.

    Science.gov (United States)

    Lo Giudice, Alessandro; Re, Alessandro; Angelici, Debora; Calusi, Silvia; Gelli, Nicla; Giuntini, Lorenzo; Massi, Mirko; Pratesi, Giovanni

    2012-07-01

    Broad beam ionoluminescence (IL) microscopy is a promising technique for the non-destructive characterisation of rocks and stone objects. Luminescence imaging by means of broad ion beams has been sporadically used by other authors but, to our knowledge, its potential has not yet been fully investigated, neither in geological science nor in other fields. The in-air broad beam IL microscope was developed and installed at the INFN-LABEC external microbeam in Florence. Similar to the cathodoluminescence (CL) microscope, the apparatus exploits a CCD colour camera collecting images (few square millimetres wide, with ~10-μm spatial resolution) of the luminescence emitted by the sample hit by a defocused megaelectron volt (MeV) proton beam. The main differences with the well-established and widespread CL are the possibility of working in air (no sampling or conductive coatings required) and the possibility of combining the analysis with microbeam analysis, such as, for example, μ-IL and μ-PIXE (particle-induced X-ray emission). To show the potential of the technique, IL images of thin sections of lapis lazuli are compared with those obtained by means of an in-vacuum cold CL. An application to the study of stone artworks is also reported. This technique and apparatus will provide a valuable help for interdisciplinary applications, e.g. in geological sciences and in the cultural heritage field.

  8. Formation Mechanism of Micropores on the Surface of Pure Aluminum Induced by High-Current Pulsed Electron Beam Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZOU Yang; CAI Jie; WAN Ming-Zhen; LV Peng; GUAN Qing-Feng

    2011-01-01

    The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained. It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation. The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along gra,in boundaries and/or dislocations towards the irradiated surface. It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.%The mechanism of micropores formed on the surface of polycrystalline pure aluminum under high-current pulsed electron beam (HCPEB) irradiation is explained.It is discovered that dispersed micropores with sizes of 0.1-1μm on the irradiated surface of pure aluminum can be successfully fabricated after HCPEB irradiation.The dominant formation mechanism of the surface micropores should be attributed to the formation of supersaturation vacancies within the near surface during the HCPEB irradiation and the migration of vacancies along grain boundaries and/or dislocations towards the irradiated surface.It is expected that the HCPEB technique will become a new method for the rapid synthesis of surface porous materials.High-current pulsed electron beams (HCPEBs)have attracted much attention in the field of material surface modification.[1-7] During the transient bombardment process a high energy (108-109 W·cm-2) is deposited only in a very thin layer (less than tens of micrometers) within a very short time (a few microseconds) and thereby causes ultrafast heating and cooling on the irradiated surface of materials.The dynamic stress fields induced in these processes can induce intense deformation on the material surface.

  9. Estimation of luminescence lifetime in frequency domain

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Xu Zheng; Zhao Su-Ling; Lou Zhi-Dong; Yang Sheng-Yi; Xu Xu-Rong

    2006-01-01

    Absorption is the origin of luminescence. But it must be noticed that the lifetime of luminescence might reversely influence the rate of absorption. In this paper, it is reported that the luminescence intensity of copper and manganese changes with the driving frequency at constant voltage. The variation of luminescent intensity depends only on the lifetime of luminescence but not on the type of quenching or other factors. Generally the rate of absorption is dominantly determined by the material property and the lifetime of luminescence centres, the absorption of shorter lifetime centre will be larger than that of the longer lifetime centre at the same excited condition.

  10. Interactions between bicarbonate, potassium, and magnesium, and sulfur-dependent induction of luminescence in Vibrio fischeri.

    Science.gov (United States)

    Tabei, Yosuke; Era, Mariko; Ogawa, Akane; Morita, Hiroshi

    2012-06-01

    In spite of its central importance in research efforts, the relationship between seawater compounds and bacterial luminescence has not previously been investigated in detail. Thus, in this study, we investigated the effect of cations (Na(+) , K(+) , NH(4) (+) , Mg(2+) , and Ca(2+) ) and anions (Cl(-) , HCO(3) (-) , CO(3) (2-) , and NO(3) (-) ) on the induction of both inorganic (sulfate, sulfite, and thiosulfate) and organic (L-cysteine and L-cystine) sulfur-dependent luminescence in Vibrio fischeri. We found that HCO(3) (-) (bicarbonate) and CO(3) (2-) (carbonate), in the form of various compounds, had a stimulatory effect on sulfur-dependent luminescence. The luminescence induced by bicarbonate was further promoted by the addition of magnesium. Potassium also increased sulfur-dependent luminescence when sulfate or thiosulfate was supplied as the sole sulfur source, but not when sulfite, L-cysteine, or L-cystine was supplied. The positive effect of potassium was accelerated by the addition of magnesium and/or calcium. Furthermore, the additional supply of magnesium improved the induction of sulfite- or L-cysteine-dependent luminescence, but not the l-cystine-dependent type. These results suggest that sulfur-dependent luminescence of V. fischeri under nutrient-starved conditions is mainly controlled by bicarbonate, carbonate, and potassium. In addition, our results indicate that an additional supply of magnesium is effective for increasing V. fischeri luminescence.

  11. Laser-Bioplasma Interaction: The Blood Type Transmutation Induced by Multiple Ultrashort Wavelength Laser Beams

    Science.gov (United States)

    Stefan, V. Alexander

    2015-11-01

    The interaction of ultrashort wavelength multi laser beams with the flowing blood thin films leads to the transmutation of the blood types A, B, and AB into O type. This is a novel mechanism of importance for the transfusion medicine. Laser radiation is in resonance with the eigen-frequency modes of the antigen proteins and forces the proteins to parametrically oscillate until they get kicked out from the surface. The stripping away of antigens is done by the scanning-multiple-lasers of a high repetition rate in the blue-purple frequency domain. The guiding-lasers are in the red-green frequency domain. The laser force, (parametric interaction with the antigen eigen-oscillation), upon the antigen protein molecule must exceed its weight. The scanning laser beam is partially reflected as long as the antigen(s) is not eliminated. The process of the protein detachment can last a few minutes. Supported by Nikola Tesla Labs., Stefan University.

  12. Recent studies of the electron cloud induced beam instability at the Los Alamos PSR

    Energy Technology Data Exchange (ETDEWEB)

    Macek, Robert James [Los Alamos National Laboratory; Mc Crady, Rodney C [Los Alamos National Laboratory; Rybarcyk, Lawrence J [Los Alamos National Laboratory; Zaugg, Thomas J [Los Alamos National Laboratory

    2010-12-09

    Recent beam studies have demonstrated that a stable beam with the standard production bunch width of 290 ns and near the e-p instability threshold will become unstable when the bunch width is shortened significantly. This was not the case years earlier when the ring rf operated at the 72.000 integer subharmonic of the Linac bunch frequency. The present operating frequency is set at the 72.070 non-integer subharmonic and appears to be responsible for the recently observed 'short pulse instability phenomenon'. Experimental characteristics of the short pulse instability are presented along with comparisons to the instability under 72.000 subharmonic operating conditions.

  13. Recent studies of the electron cloud induced beam instability at the Los Alamos PSR

    Energy Technology Data Exchange (ETDEWEB)

    Macek, Robert James [Los Alamos National Laboratory; Mc Crady, Rodney C [Los Alamos National Laboratory; Rybarcyk, Lawrence J [Los Alamos National Laboratory; Zaugg, Thomas J [Los Alamos National Laboratory; Holmes, Jeffrey A [SNS, ORNL

    2011-01-06

    Recent beam studies have demonstrated that a stable beam with the standard production bunch width of 290 ns and near the e-p instability threshold will become unstable when the bunch width is shortened significantly. This was not the case years earlier when the ring rf operated at the 72.000 integer subharmonic of the Linac bunch frequency. The present operating frequency is set at the 72.070 non-integer subharmonic and appears to be responsible for the recently observed 'short pulse instability phenomenon'. Experimental characteristics of the short pulse instability are presented along with comparisons to the instability under 72.000 subharmonic operating conditions.

  14. Langmuir Wave Electric Fields Induced by Electron Beams in the Heliosphere

    CERN Document Server

    Reid, Hamish A S

    2016-01-01

    Solar electron beams responsible for type III radio emission generate Langmuir waves as they propagate out from the Sun. The Langmuir waves are observed via in-situ electric field measurements. These Langmuir waves are not smoothly distributed but occur in discrete clumps, commonly attributed to the turbulent nature of the solar wind electron density. Exactly how the density turbulence modulates the Langmuir wave electric fields is understood only qualitatively. Using weak turbulence simulations, we investigate how solar wind density turbulence changes the probability distribution functions, mean value and variance of the beam-driven electric field distributions. Simulations show rather complicated forms of the distribution that are dependent upon how the electric fields are sampled. Generally the higher magnitude of density fluctuations reduce the mean and increase the variance of the distribution in a consistent manor to the predictions from resonance broadening by density fluctuations. We also demonstrate ...

  15. Calculation of electron-beam induced displacement in thin films by using parameter-reduced formulas

    Science.gov (United States)

    Yan, Qiang; Chen, Di; Wang, Qingyu; Li, Zhongyu; Shao, Lin

    2017-03-01

    Based on the Mott cross sections of relativistic electron collisions with atoms, we calculate displacement creation by electron beams of arbitrary energies (up to 100 MeV) in thin films of arbitrary atomic numbers (up to Z = 90). In a comparison with Mont Carlo full damage cascade simulations, we find that total number of displacements in a film can be accurately estimated as the product of average displacements created per collision and average collision numbers in the film. To calculate average displacements per electron-atom collision, energy transfer from Mott cross section is combined with NRT model. To calculate collision numbers, mean deflection angles and multi-scattering theory are combined to extract collision number dependence on film thickness. For each key parameter, parameter-reduced formulas are obtained from data fitting. The fitting formulas provide a quick and accurate method to estimate radiation damage caused by electron beams.

  16. Studies of the Machine Induced Background, simulations for the design of the Beam Condition Monitor and implementation of the Inclusive $\\phi$ Trigger at the LHCb experiment at CERN

    CERN Document Server

    Lieng, Magnus

    2011-01-01

    LHCb is one of the four major experiments of the LHC at CERN, built to perform precision measurements of CP violation and rare decays. In order to protect the sensitive elements of the experiment from adverse beam conditions the Beam Condition Monitor has been created. Such conditions increase the particle flux arriving from the LHC, known as Machine Induced Background. These particles interfere with the experiment, for example through the physics trigger. In this thesis software development and simulations for the design and validation of the Beam Condition Monitor is shown, ranging from LHCb-specific algorithm implementation to beam dump threshold determination. Furthermore, software development in order to attain a complete simulation chain of machine induced background is shown. The results of these simulations are compared to early data collected at LHCb. Lastly, the development and implementation of the Inclusive $\\phi$ trigger line for the High Level Trigger is presented. This line aims to reconstruct ...

  17. DYNAMICS OF IONIZATION-ENHANCED SPECTRAL EXPANSION IN WATER INDUCED BY AN INTENSE FEMTOSECOND LASER BEAM

    Institute of Scientific and Technical Information of China (English)

    WANG SHU-FENG; QIN YUAN-DONG; YANG HONG; WANG DAN-LING; ZHU CHANG-JUN; GONG QI-HUANG

    2001-01-01

    The dynamic process of white-continuum generation in water was investigated by the pump-probe technique with a femtosecond intense laser at 805nm. The spectrum width of the probe beam was broadened at the blue side and varied with different delay times. This blueshift was attributed to the ionization-enhanced optical nonlinearity, in which both the multi-photon ionization and avalanche ionization had an effect.

  18. Zakharov simulations of beam-induced turbulence in the auroral ionosphere

    Science.gov (United States)

    Akbari, H.; Guio, P.; Hirsch, M. A.; Semeter, J. L.

    2016-05-01

    Recent detections of strong incoherent scatter radar echoes from the auroral F region, which have been explained as the signature of naturally produced Langmuir turbulence, have motivated us to revisit the topic of beam-generated Langmuir turbulence via simulation. Results from one-dimensional Zakharov simulations are used to study the interaction of ionospheric electron beams with the background plasma at the F region peak. A broad range of beam parameters extending by more than 2 orders of magnitude in average energy and electron number density is considered. A range of wave interaction processes, from a single parametric decay, to a cascade of parametric decays, to formation of stationary density cavities in the condensate region, and to direct collapse at the initial stages of turbulence, is observed as we increase the input energy to the system. The effect of suprathermal electrons, produced by collisional interactions of auroral electrons with the neutral atmosphere, on the dynamics of Langmuir turbulence is also investigated. It is seen that the enhanced Landau damping introduced by the suprathermal electrons significantly weakens the turbulence and truncates the cascade of parametric decays.

  19. Error-Induced Beam Degradation in Fermilab's Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sung-Young Phil [Univ. of Rochester, NY (United States)

    2008-01-01

    In Part I, three independent models of Fermilab's Booster synchrotron are presented. All three models are constructed to investigate and explore the effects of unavoidable machine errors on a proton beam under the influence of space-charge effects. The first is a stochastic noise model. Electric current fluctuations arising from power supplies are ubiquitous and unavoidable and are a source of instabilities in accelerators of all types. A new noise module for generating the Ornstein-Uhlenbeck (O-U) stochastic noise is first created and incorporated into the existing Object-oriented Ring Beam Injection and Tracking (ORBIT-FNAL) package. After being convinced with a preliminary model that the noise, particularly non-white noise, does matter to beam quality, we proceeded to measure directly current ripples and common-mode voltages from all four Gradient Magnet Power Supplies (GMPS). Then, the current signals are Fourier-analyzed. Based upon the power spectra of current signals, we tune up the Ornstein-Uhlnbeck noise model. As a result, we are able to closely match the frequency spectra between current measurements and the modeled O-U stochastic noise. The stochastic noise modeled upon measurements is applied to the Booster beam in the presence of the full space-charge effects. This noise model, accompanied by a suite of beam diagnostic calculations, manifests that the stochastic noise, impinging upon the beam and coupled to the space-charge effects, can substantially enhance the beam degradation process throughout the injection period. The second model is a magnet misalignment model. It is the first time to utilize the latest beamline survey data for building a magnet-by-magnet misalignment model. Given as-found survey fiducial coordinates, we calculate all types of magnet alignment errors (station error, pitch, yaw, roll, twists, etc.) are implemented in the model. We then follow up with statistical analysis to understand how each type of alignment errors are

  20. Error-Induced Beam Degradation in Fermilab's Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sung-Young Phil [Univ. of Rochester, NY (United States)

    2008-01-01

    In Part I, three independent models of Fermilab's Booster synchrotron are presented. All three models are constructed to investigate and explore the effects of unavoidable machine errors on a proton beam under the influence of space-charge effects. The first is a stochastic noise model. Electric current fluctuations arising from power supplies are ubiquitous and unavoidable and are a source of instabilities in accelerators of all types. A new noise module for generating the Ornstein-Uhlenbeck (O-U) stochastic noise is first created and incorporated into the existing Object-oriented Ring Beam Injection and Tracking (ORBIT-FNAL) package. After being convinced with a preliminary model that the noise, particularly non-white noise, does matter to beam quality, we proceeded to measure directly current ripples and common-mode voltages from all four Gradient Magnet Power Supplies (GMPS). Then, the current signals are Fourier-analyzed. Based upon the power spectra of current signals, we tune up the Ornstein-Uhlnbeck noise model. As a result, we are able to closely match the frequency spectra between current measurements and the modeled O-U stochastic noise. The stochastic noise modeled upon measurements is applied to the Booster beam in the presence of the full space-charge effects. This noise model, accompanied by a suite of beam diagnostic calculations, manifests that the stochastic noise, impinging upon the beam and coupled to the space-charge effects, can substantially enhance the beam degradation process throughout the injection period. The second model is a magnet misalignment model. It is the first time to utilize the latest beamline survey data for building a magnet-by-magnet misalignment model. Given as-found survey fiducial coordinates, we calculate all types of magnet alignment errors (station error, pitch, yaw, roll, twists, etc.) are implemented in the model. We then follow up with statistical analysis to understand how each type of alignment errors are

  1. Thon rings from amorphous ice and implications of beam-induced Brownian motion in single particle electron cryo-microscopy.

    Science.gov (United States)

    McMullan, G; Vinothkumar, K R; Henderson, R

    2015-11-01

    We have recorded dose-fractionated electron cryo-microscope images of thin films of pure flash-frozen amorphous ice and pre-irradiated amorphous carbon on a Falcon II direct electron detector using 300 keV electrons. We observe Thon rings [1] in both the power spectrum of the summed frames and the sum of power spectra from the individual frames. The Thon rings from amorphous carbon images are always more visible in the power spectrum of the summed frames whereas those of amorphous ice are more visible in the sum of power spectra from the individual frames. This difference indicates that while pre-irradiated carbon behaves like a solid during the exposure, amorphous ice behaves like a fluid with the individual water molecules undergoing beam-induced motion. Using the measured variation in the power spectra amplitude with number of electrons per image we deduce that water molecules are randomly displaced by a mean squared distance of ∼1.1 Å(2) for every incident 300 keV e(-)/Å(2). The induced motion leads to an optimal exposure with 300 keV electrons of 4.0 e(-)/Å(2) per image with which to observe Thon rings centred around the strong 3.7 Å scattering peak from amorphous ice. The beam-induced movement of the water molecules generates pseudo-Brownian motion of embedded macromolecules. The resulting blurring of single particle images contributes an additional term, on top of that from radiation damage, to the minimum achievable B-factor for macromolecular structure determination.

  2. Turning on the Light: Lessons from Luminescence

    Science.gov (United States)

    O'Hara, Patricia B.; Engelson, Carol; St. Peter, Wayne

    2005-01-01

    Some of the processes by which light is emitted without a simultaneous change in temperature are discussed and is classified as luminescence or cold light. Luminescent processes include triboluminescence, fluorescence, phosphorescence, chemiluminescence, and bioluminescence.

  3. Luminescence sensitivity changes in quartz

    CERN Document Server

    Wintle, A G

    1999-01-01

    In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

  4. Electron Induced Surface Reactions of cis-Pt(CO)2Cl2: A Route to Focused Electron Beam Induced Deposition of Pure Pt Nanostructures.

    Science.gov (United States)

    Spencer, Julie A; Wu, Yung-Chien; McElwee-White, Lisa; Fairbrother, D Howard

    2016-07-27

    Using mechanistic data from surface science studies on electron-induced reactions of organometallic precursors, cis-Pt(CO)2Cl2 (1) was designed specifically for use in focused electron beam induced deposition (FEBID) of Pt nanostructures. Electron induced decomposition of adsorbed 1 under ultrahigh vacuum (UHV) conditions proceeds through initial CO loss as determined by in situ X-ray photoelectron spectroscopy and mass spectrometry. Although the Pt-Cl bonds remain intact during the initial decomposition step, larger electron doses induce removal of the residual chloride through an electron-stimulated desorption process. FEBID structures created from cis-Pt(CO)2Cl2 under steady state deposition conditions in an Auger spectrometer were determined to be PtCl2, free of carbon and oxygen. Coupled with the electron stimulated removal of chlorine demonstrated in the UHV experiments, the Auger deposition data establish a route to FEBID of pure Pt. Results from this study demonstrate that structure-activity relationships can be used to design new precursors specifically for FEBID.

  5. Method of measuring luminescence of a material

    Science.gov (United States)

    Miller, Steven D.

    2015-12-15

    A method of measuring luminescence of a material is disclosed. The method includes applying a light source to excite an exposed material. The method also includes amplifying an emission signal of the material. The method further includes measuring a luminescent emission at a fixed time window of about 10 picoseconds to about 10 nanoseconds. The luminescence may be radio photoluminescence (RPL) or optically stimulated luminescence (OSL).

  6. Ion irradiation effect of alumina and its luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Yasushi; Yamamoto, Shunya; Naramoto, Hiroshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; My, N.T.

    1997-03-01

    The luminescence spectra of single crystalline alpha-alumina and ruby which has 0.02% of Cr{sub 2}O{sub 3} as a impurity, induced by 200 keV He{sup +} and Ar{sup +} irradiation were measured at room temperature as a function of irradiation dose. The analysis of the measured spectra showed the existence of three main luminescence features in the wavelength region of 250 to 350 nm, namely anionic color centers, F-center at 411 nm and F{sup +}-center at 330 nm and a band observed around 315 nm. As alpha-alumina was irradiated with He{sup +}, F-center and F{sup +}-center luminescence grew and decayed, but the behaviors of those were different from each other. It seems that a concentration quenching occurred on the F-center luminescence in the dose range above 1x10{sup 14} He/cm{sup 2}. Furthermore, F-center luminescence was strongly suppressed in ruby, compared with that in alumina. On the other hand, the luminescence band around 315 nm appeared only in the early stage of irradiation and did not show its growth part. The dose dependent behavior was similar to that of Cr{sup 3+} emission at 695 nm (R-line) in ruby in both cases of He{sup +} and Ar{sup +} irradiation. Based on the experimental results mentioned above, the processes of defect formation and excitation in alumina in the early stage of ion irradiation will be discussed. (author)

  7. Characterizing a multi-MeV e-beam induced plasma through visible spectroscopy and imaging

    Science.gov (United States)

    D'Almeida, Thierry; Ribiere, Maxime; Maisonny, Rémi; Ritter, Sandra; Plouhinec, Damien; Auriel, Gérard

    2016-10-01

    High energy electrons interaction and propagation mechanisms in solid targets have a broad range of applications in high energy density physics. The latter include fast ignition for inertial fusion research, production of ultra-high mechanical stress levels, plasma interactions with e-beam particles in electron diodes, radiative hydrodynamic models...This paper presents the results from recent experiments conducted on the multi-MeV generator ASTERIX operated at CEA-Gramat. This high flux density electron beam was launched from an aluminum cathode onto an aluminum-tantalum target for voltage and current of 2.4 MeV and 55 kA, respectively. A set of optical diagnostics were fielded in all of the experiments, including a UV-visible spectrometers and a fast imaging. The imaging data obtained during the experiment allowed for the ablated species velocity to be determined. based on spectroscopic analysis, the light emission was attributed to aluminum and tantalum excited atoms and ions. The analysis of this time-integrated spectrum based on radiative transfer model clearly unveiled two distinct regions of the plasma over its expansion: a hot core surrounded by a cold vapor. A quantitative analysis of these results is presented.

  8. Simulation of beam-induced plasma in gas-filled rf cavities

    Science.gov (United States)

    Yu, Kwangmin; Samulyak, Roman; Yonehara, Katsuya; Freemire, Ben

    2017-03-01

    Processes occurring in a radio-frequency (rf) cavity, filled with high pressure gas and interacting with proton beams, have been studied via advanced numerical simulations. Simulations support the experimental program on the hydrogen gas-filled rf cavity in the Mucool Test Area (MTA) at Fermilab, and broader research on the design of muon cooling devices. space, a 3D electromagnetic particle-in-cell (EM-PIC) code with atomic physics support, was used in simulation studies. Plasma dynamics in the rf cavity, including the process of neutral gas ionization by proton beams, plasma loading of the rf cavity, and atomic processes in plasma such as electron-ion and ion-ion recombination and electron attachment to dopant molecules, have been studied. Through comparison with experiments in the MTA, simulations quantified several uncertain values of plasma properties such as effective recombination rates and the attachment time of electrons to dopant molecules. Simulations have achieved very good agreement with experiments on plasma loading and related processes. The experimentally validated code space is capable of predictive simulations of muon cooling devices.

  9. Langmuir wave electric fields induced by electron beams in the heliosphere

    Science.gov (United States)

    Reid, Hamish A. S.; Kontar, Eduard P.

    2017-01-01

    Solar electron beams responsible for type III radio emission generate Langmuir waves as they propagate out from the Sun. The Langmuir waves are observed via in situ electric field measurements. These Langmuir waves are not smoothly distributed but occur in discrete clumps, commonly attributed to the turbulent nature of the solar wind electron density. Exactly how the density turbulence modulates the Langmuir wave electric fields is understood only qualitatively. Using weak turbulence simulations, we investigate how solar wind density turbulence changes the probability distribution functions, mean value and variance of the beam-driven electric field distributions. Simulations show rather complicated forms of the distribution that are dependent upon how the electric fields are sampled. Generally the higher magnitude of density fluctuations reduce the mean and increase the variance of the distribution in a consistent manor to the predictions from resonance broadening by density fluctuations. We also demonstrate how the properties of the electric field distribution should vary radially from the Sun to the Earth and provide a numerical prediction for the in situ measurements of the upcoming Solar Orbiter and Solar Probe Plus spacecraft.

  10. Heavy Ion Beams Induce Survivin Expression in Human Hepatoma SMMC-7721 Cells More Effectively than X-rays

    Institute of Scientific and Technical Information of China (English)

    Li GONG; Xiaodong JIN; Qiang LI; Jiangtao LIU; Lizhe AN

    2007-01-01

    High linear energy transfer (LET) heavy ion radiation is more effective in inducing biological damage than low-LET X-rays or γ-rays. Heavy ion beam provides good dose localization (Bragg peak) in critical cancer tissue and gives higher relative biological effectiveness in cell killing across the dose peak, so high-LET heavy ion beam is superior to low-LET radiation in cancer treatment. Survivin, as a member of the inhibitor of apoptosis protein family, might help cancerous cells to overcome the G2/M apoptotic checkpoint and favor the aberrant progression of transformed cells through mitosis. Survivin expression in the human hepatoma SMMC-7721 cell line after exposure to low-LET X-ray and high-LET carbon ion irradiation was investigated in this study. Compared with X-ray irradiation, the carbon ion beam clearly caused G2/M arrest and promoted the expression of the survivin gene in a dose-dependent manner. Clonogenic survival assay showed that SMMC-7721 cells were more radiosensitive to the high-LET carbon ions than to the X-rays, and the radiosensitivity was promoted after treatment with specific survivin short interfering RNA. Differential survivin expression at both transcriptional and translational levels was found for SMMC-7721 cells following low- and high-LET irradiation. The overexpression of survivin in SMMC-7721 cells is probably an important reason why the cancerous cells have radioresistance to strong stimulus such as dense ionizing high-LET radiation. However, the direct killing effect on cancerous cells by high-LET radiation might be more significant than the apoptosis inhibition through the overexpression of survivin following heavy ion irradiation.

  11. Self absorption in luminescent solar concentrators

    NARCIS (Netherlands)

    Krumer, Z.

    2014-01-01

    Luminescent solar concentrators are photovoltaic devices made of thin transparent material, in which luminescent particles are dispersed. The incident light enters the device through its large facets and is subsequently absorbed by the luminescent particles, which re-emit it whilst changing its dire

  12. Nitric oxide in the control of luminescence from lantern shark (Etmopterus spinax) photophores.

    Science.gov (United States)

    Claes, Julien M; Krönström, Jenny; Holmgren, Susanne; Mallefet, Jérôme

    2010-09-01

    Photophores (photogenic organs) of the lantern shark Etmopterus spinax are under hormonal control, with prolactin (PRL) and melatonin (MT) triggering the light emission. Differential sensitivity to these hormones in adult individuals suggests, however, that the luminescence of this shark is controlled by an additional mechanism. In this study, different techniques were used to investigate a potential modulator of E. spinax luminescence - nitric oxide (NO). NO synthase (NOS)-like immunoreactivity (IR) was found in the photocytes (photogenic cells) of the photophores. In addition, acetylated tubulin IR also supported the presence of nerves running through the photogenic tissue and innervating different structural elements of the photophores: photocytes, pigmented cells from the iris-like structure and lens cells. Pharmacological experiments confirmed a modulatory action of NO on the hormonally induced luminescence: NO donors sodium nitroprusside (SNP) and hydroxylamine decreased the time to reach the maximum amplitude (TL(max)) of MT-induced luminescence while these substances decreased the maximum amplitude of PRL-induced luminescence (and also the TL(max) in the case of SNP). The small impact of the NOS inhibitor l-NAME on hormonally induced luminescence suggests that NO is only produced on demand. The cGMP analogue 8BrcGMP mimicked the effects of NO donors suggesting that the effects of NO are mediated by cGMP.

  13. Cavity-induced phase stability to decelerate a fast molecular beam via feedback-controlled time-varying optical pumps

    CERN Document Server

    Lan, Zhihao

    2014-01-01

    We have identified a novel phase stability mechanism from the intracavity field-induced self-organization of a fast-moving molecular beam into travelling molecular packets in the bad cavity regime, which is then used to decelerate the molecular packets by feedback-controlled time-varying laser pumps to the cavity. We first applied the linear stability analysis to derive an expression for this self-organization in the adiabatic limit and show that the self-organization of the beam leads to the formation of travelling molecular packets, which in turn function as a dynamic Bragg grating, thus modulating periodically the intracavity field by superradiant scattering of the pump photons. The modulation encodes the position information of the molecular packets into the output of the intracavity field instantaneously. We then applied time-varying laser pumps that are automatically switched by the output of the intracavity field to slow down the molecular packets via a feedback mechanism and found that most of the mol...

  14. High speed, intermediate resolution, large area laser beam induced current imaging and laser scribing system for photovoltaic devices and modules

    Science.gov (United States)

    Phillips, Adam B.; Song, Zhaoning; DeWitt, Jonathan L.; Stone, Jon M.; Krantz, Patrick W.; Royston, John M.; Zeller, Ryan M.; Mapes, Meghan R.; Roland, Paul J.; Dorogi, Mark D.; Zafar, Syed; Faykosh, Gary T.; Ellingson, Randy J.; Heben, Michael J.

    2016-09-01

    We have developed a laser beam induced current imaging tool for photovoltaic devices and modules that utilizes diode pumped Q-switched lasers. Power densities on the order of one sun (100 mW/cm2) can be produced in a ˜40 μm spot size by operating the lasers at low diode current and high repetition rate. Using galvanostatically controlled mirrors in an overhead configuration and high speed data acquisition, large areas can be scanned in short times. As the beam is rastered, focus is maintained on a flat plane with an electronically controlled lens that is positioned in a coordinated fashion with the movements of the mirrors. The system can also be used in a scribing mode by increasing the diode current and decreasing the repetition rate. In either mode, the instrument can accommodate samples ranging in size from laboratory scale (few cm2) to full modules (1 m2). Customized LabVIEW programs were developed to control the components and acquire, display, and manipulate the data in imaging mode.

  15. High speed, intermediate resolution, large area laser beam induced current imaging and laser scribing system for photovoltaic devices and modules.

    Science.gov (United States)

    Phillips, Adam B; Song, Zhaoning; DeWitt, Jonathan L; Stone, Jon M; Krantz, Patrick W; Royston, John M; Zeller, Ryan M; Mapes, Meghan R; Roland, Paul J; Dorogi, Mark D; Zafar, Syed; Faykosh, Gary T; Ellingson, Randy J; Heben, Michael J

    2016-09-01

    We have developed a laser beam induced current imaging tool for photovoltaic devices and modules that utilizes diode pumped Q-switched lasers. Power densities on the order of one sun (100 mW/cm(2)) can be produced in a ∼40 μm spot size by operating the lasers at low diode current and high repetition rate. Using galvanostatically controlled mirrors in an overhead configuration and high speed data acquisition, large areas can be scanned in short times. As the beam is rastered, focus is maintained on a flat plane with an electronically controlled lens that is positioned in a coordinated fashion with the movements of the mirrors. The system can also be used in a scribing mode by increasing the diode current and decreasing the repetition rate. In either mode, the instrument can accommodate samples ranging in size from laboratory scale (few cm(2)) to full modules (1 m(2)). Customized LabVIEW programs were developed to control the components and acquire, display, and manipulate the data in imaging mode.

  16. Towards a single step process to create high purity gold structures by electron beam induced deposition at room temperature

    Science.gov (United States)

    Mansilla, C.; Mehendale, S.; Mulders, J. J. L.; Trompenaars, P. H. F.

    2016-10-01

    Highly pure metallic structures can be deposited by electron beam induced deposition and they have many important applications in different fields. The organo-metallic precursor is decomposed and deposited under the electron beam, and typically it is purified with post-irradiation in presence of O2. However, this approach limits the purification to the surface of the deposit. Therefore, ‘in situ’ purification during deposition using simultaneous flows of both O2 and precursor in parallel with two gas injector needles has been tested and verified. To simplify the practical arrangements, a special concentric nozzle has been designed allowing deposition and purification performed together in a single step. With this new device metallic structures with high purity can be obtained more easily, while there is no limit on the height of the structures within a practical time frame. In this work, we summarize the first results obtained for ‘in situ’ Au purification using this concentric nozzle, which is described in more detail, including flow simulations. The operational parameter space is explored in order to optimize the shape as well as the purity of the deposits, which are evaluated through scanning electron microscope and energy dispersive x-ray spectroscopy measurements, respectively. The observed variations are interpreted in relation to other variables, such as the deposition yield. The resistivity of purified lines is also measured, and the influence of additional post treatments as a last purification step is studied.

  17. A luminescent nanocrystal stress gauge

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Charina; Koski, Kristie; Olson, Andrew; Alivisatos, Paul

    2010-10-25

    Microscale mechanical forces can determine important outcomes ranging from the site of material fracture to stem cell fate. However, local stresses in a vast majority of systems cannot be measured due to the limitations of current techniques. In this work, we present the design and implementation of the CdSe/CdS core/shell tetrapod nanocrystal, a local stress sensor with bright luminescence readout. We calibrate the tetrapod luminescence response to stress, and use the luminescence signal to report the spatial distribution of local stresses in single polyester fibers under uniaxial strain. The bright stress-dependent emission of the tetrapod, its nanoscale size, and its colloidal nature provide a unique tool that may be incorporated into a variety of micromechanical systems including materials and biological samples to quantify local stresses with high spatial resolution.

  18. Micro-modulated luminescence tomography

    CERN Document Server

    Cong, Wenxiang; Wang, Chao; Wang, Ge

    2013-01-01

    Imaging depth of optical microscopy has been fundamentally limited to millimeter or sub-millimeter due to light scattering. X-ray microscopy can resolve spatial details of few microns deeply inside a sample but the contrast resolution is still inadequate to depict heterogeneous features at cellular or sub-cellular levels. To enhance and enrich biological contrast at large imaging depth, various nanoparticles are introduced and become essential to basic research and molecular medicine. Nanoparticles can be functionalized as imaging probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+ nanoparticles were recently synthesized to facilitate luminescence energy storage with x-ray pre-excitation and the subsequently stimulated luminescence emission by visible/near-infrared (NIR) light. In this paper, we suggest a micro-modulated luminescence tomography (MLT) approach to quantify a nanophosphor distribution in a thick biological sample with high resolution. Our numerical simulation studies demonst...

  19. Plasmonic Gold Helices for the visible range fabricated by oxygen plasma purification of electron beam induced deposits

    CERN Document Server

    Haverkamp, Caspar; Jäckle, Sara; Manzoni, Anna; Christiansen, Silke

    2016-01-01

    Electron beam induced deposition (EBID) currently provides the only direct writing technique for truly three-dimensional nanostructures with geometrical features below 50 nm. Unfortunately, the depositions from metal-organic precursors suffer from a substantial carbon content. This hinders many applications, especially in plasmonics where the metallic nature of the geometric surfaces is mandatory. To overcome this problem a post-deposition treatment with oxygen plasma at room temperature was investigated for the purification of gold containing EBID structures. Upon plasma treatment, the structures experience a shrinkage in diameter of about 18 nm but entirely keep their initial shape. The proposed purification step results in a core-shell structure with the core consisting of mainly unaffected EBID material and a gold shell of about 20 nm in thickness. These purified structures are plasmonically active in the visible wavelength range as shown by dark field optical microscopy on helical nanostructures. Most no...

  20. Surface Nanocrystallization of 3Cr13 Stainless Steel Induced by High-Current Pulsed Electron Beam Irradiation

    Directory of Open Access Journals (Sweden)

    Zhiyong Han

    2013-01-01

    Full Text Available The nanocrystalline surface was produced on 3Cr13 martensite stainless steel surface using high-current pulsed electron beam (HCPEB technique. The structures of the nanocrystallized surface were characterized by X-ray diffraction and electron microscopy. Two nanostructures consisting of fine austenite grains (50–150 nm and very fine carbides precipitates are formed in melted surface layer after multiple bombardments via dissolution of carbides and crater eruption. It is demonstrated that the dissolution of the carbides and the formation of the supersaturated Fe (C solid solution play a determining role on the microstructure evolution. Additionally, the formation of fine austenite structure is closely related to the thermal stresses induced by the HCPEB irradiation. The effects of both high carbon content and high value of stresses increase the stability of the austenite, which leads to the complete suppression of martensitic transformation.

  1. Study on the effect of beam propagation through atmospheric turbulence on standoff nanosecond laser induced breakdown spectroscopy measurements.

    Science.gov (United States)

    Laserna, J J; Reyes, R Fernández; González, R; Tobaria, L; Lucena, P

    2009-06-08

    We report on an experimental study of the effect of atmospheric turbulence on laser induced breakdown spectroscopy (LIBS) measurements. The characteristics of the atmosphere dictate specific performance constraints to this technology. Unlike classical laboratory LIBS systems where the distance to the sample is well known and characterized, LIBS systems working at several tens of meters to the target have specific atmospheric propagation conditions that cause the quality of the LIBS signals to be affected to a significant extent. Using a new LIBS based sensor system fitted with a nanosecond laser emitting at 1064 nm, propagation effects at distances of up to 120 m were investigated. The effects observed include wander and scintillation in the outgoing laser beam and in the return atomic emission signal. Plasmas were formed on aluminium targets. Average signal levels and signal fluctuations are measured so the effect of atmospheric turbulence on LIBS measurements is quantified.

  2. 2p1v states populated in 135Te from 9Be induced reactions with a 132Sn beam

    Energy Technology Data Exchange (ETDEWEB)

    Allmond, James M [ORNL; Stuchbery, Andrew E [ORNL; Brown, Alex [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University; Beene, James R [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Gross, Carl J [ORNL; Liang, J Felix [ORNL; Padilla-Rodal, Elizabeth [Universidad Nacional Autonoma de Mexico (UNAM); Radford, David C [ORNL; Varner Jr, Robert L [ORNL; Ayres, A. [University of Tennessee, Knoxville (UTK); Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Bey, A. [University of Tennessee, Knoxville (UTK); Bingham, C. R. [University of Tennessee, Knoxville (UTK); Howard, Meredith E [ORNL; Jones, K. L. [University of Tennessee, Knoxville (UTK); Manning, Brett M [ORNL; Mueller, Paul Edward [ORNL; Nesaraja, Caroline D [ORNL; Pain, Steven D [ORNL; Peters, William A [ORNL; Ratkiewicz, Andrew J [ORNL; Schmitt, Kyle [University of Tennessee, Knoxville (UTK); Shapira, Dan [ORNL; Smith, Michael Scott [ORNL; Stone, N. J. [University of Tennessee, Knoxville (UTK); Stracener, Daniel W [ORNL; Yu, Chang-Hong [ORNL

    2014-01-01

    Gamma-ray transitions in $^{134}$\\textrm{Te}, $^{135}$\\textrm{Te}, and $^{136}$\\textrm{Te} were measured from $^{9}$\\textrm{Be} induced reactions with a radioactive $^{132}$\\textrm{Sn} beam at a sub-Coulomb barrier energy of $3$~MeV per nucleon using particle-$\\gamma$ coincidence spectroscopy. The transitions were selected by gating on alpha-like particles in a \\textrm{CsI} detector following a combination of ($^{9}$\\textrm{Be},$\\alpha 1n$), ($^{9}$\\textrm{Be},$\\alpha 2n$), and ($^{9}$\\textrm{Be},$\\alpha 3n$) reactions. Distorted wave Born approximation calculations suggest little to no contribution from the ($^{9}$\\textrm{Be},$^{7}$\\textrm{He}), ($^{9}$\\textrm{Be},$^{6}$\\textrm{He}), and ($^{9}$\\textrm{Be},$^{5}$\\textrm{He}) direct reactions. Gamma-ray transitions from previously known $2^+\\otimes \

  3. Laser-beam-induced current mapping evaluation of porous silicon-based passivation in polycrystalline silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Rabha, M. Ben; Bessais, B. [Laboratoire de Nanomateriaux et des Systemes pour l' Energie, Centre de Recherches et des Technologies de l' Energie - Technopole de Borj-Cedria BP 95, 2050 Hammam-Lif (Tunisia); Dimassi, W.; Bouaicha, M.; Ezzaouia, H. [Laboratoire de photovoltaique, des semiconducteurs et des nanostructures, Centre de Recherches et des Technologies de l' Energie - Technopole de Borj-Cedria BP 95, 2050 Hammam-Lif (Tunisia)

    2009-05-15

    In the present work, we report on the effect of introducing a superficial porous silicon (PS) layer on the performance of polycrystalline silicon (pc-Si) solar cells. Laser-beam-induced current (LBIC) mapping shows that the PS treatment on the emitter of pc-Si solar cells improves their quantum response and reduce the grain boundaries (GBs) activity. After the porous silicon treatment, mapping investigation shows an enhancement of the LBIC and the internal quantum efficiency (IQE), due to an improvement of the minority carrier diffusion length and the passivation of recombination centers at the GBs as compared to the reference substrate. It was quantitatively shown that porous silicon treatment can passivate both the grains and GBs. (author)

  4. Impurity heterogeneity in natural pyrite and its relation to internal electric fields mapped using remote laser beam induced current

    Energy Technology Data Exchange (ETDEWEB)

    Laird, Jamie S., E-mail: csirojamie@gmail.com [CSIRO, Earth Science and Resource Engineering, Clayton, Victoria (Australia); Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); School of Physics, University of Melbourne, Parkville 3010, Victoria (Australia); Large, Ross [Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); Ryan, Chris G. [CSIRO, Earth Science and Resource Engineering, Clayton, Victoria (Australia); Centre of Excellence in Ore Deposits (CODES), University of Tasmania, Hobart, Tasmania (Australia); School of Physics, University of Melbourne, Parkville 3010, Victoria (Australia)

    2013-07-01

    Regions of band-bending in naturally occurring semiconducting sulfides are thought to drive electrochemical reactions with passing fluids. Metal bearing fluids within the right pH range interact with the electric fields at the surface resulting in precious metal ore genesis, even in under-saturated solutions. Metal reduction at the surface occurs via field assisted electron transfer from the semiconductor bulk to the ion in solution via surface states. Better understanding the role these regions and their texturing play on nucleating ore growth requires imaging of electric field distributions near the sulfide surface and correlation with underlying elemental heterogeneity. In this paper we discuss PIXE measurements made on the CSIRO Nuclear Microprobe and correlate elemental maps with laser beam induced current maps of the electric field distribution.

  5. Distribution of products in polymer materials induced by ion-beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Masaki; Kudoh, Hisaaki; Sasuga, Tsuneo; Seguchi, Tadao [Japan Atomic Energy Research Inst., Tokyo (Japan); Hama, Yoshimasa; Hamanaka, Ken-ichi; Matsumoto, Hideya

    1997-03-01

    The depth profile of double bond formed in low density polyethylene (LDPE) sheet by ion beams irradiation was observed by a micro FT-IR spectrometer in order to investigate the linear energy transfer (LET) dependency on radiation effects to polymer materials. The distribution of double bond formation in LDPE by irradiation of light ions as H+ was found to be same with the dose distribution calculated from TRIM code, and the yield was also same with that by gamma-rays irradiation, which means that the LET dependency is very small. However, the distribution of double bond to depth was much different from the calculated depth-dose in heavy ions irradiation as Ar and Kr. Then, the dose evaluation was difficult from the TRIM code calculation for heavy ions. (author)

  6. Radiation reaction induced spiral attractors in ultra-intense colliding laser beams

    CERN Document Server

    Gong, Z; Shou, Y R; Qiao, B; Chen, C E; Xu, F R; He, X T; Yan, X Q

    2016-01-01

    The radiation reaction effects on electron dynamics in counter-propagating circularly polarized laser beams are investigated through the linearization theorem and the results are in great agreement with numeric solutions. For the first time, the properties of fixed points in electron phase-space were analyzed with linear stability theory, showing that center nodes will become attractors if the classical radiation reaction is considered. Electron dynamics are significantly affected by the properties of the fixed points and the electron phase-space densities are found to be increasing exponentially near the attractors. The density growth rates are derived theoretically and further verified by particle-in-cell simulations, which can be detected in experiments to explore the effects of radiation reaction qualitatively. The attractor can also facilitate to realize a series of nanometer-scaled flying electron slices via adjusting the colliding laser frequencies.

  7. Induced radioactivity in the target station and decay tunnel from a 4MW proton beam

    CERN Document Server

    Agosteo, S; Otto, T; Silari, Marco

    2003-01-01

    An important aspect of a future CERN Neutrino Factory is the material activation arising from a 2.2 GeV, 4 MW proton beam striking a mercury target. A first estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump has been performed by the Monte Carlo hadronic cascade code FLUKA. The aim is both to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which will have to be disposed of after the facility has ceased operation. This paper discusses the first results of such calculations.

  8. Texture-Induced Anisotropy in an Inconel 718 Alloy Deposited Using Electron Beam Freeform Fabrication

    Science.gov (United States)

    Tayon, W.; Shenoy, R.; Bird, R.; Hafley, R.; Redding, M.

    2014-01-01

    A test block of Inconel (IN) 718 was fabricated using electron beam freeform fabrication (EBF(sup 3)) to examine how the EBF(sup 3) deposition process affects the microstructure, crystallographic texture, and mechanical properties of IN 718. Tests revealed significant anisotropy in the elastic modulus for the as-deposited IN 718. Subsequent tests were conducted on specimens subjected to a heat treatment designed to decrease the level of anisotropy. Electron backscatter diffraction (EBSD) was used to characterize crystallographic texture in the as-deposited and heat treated conditions. The anisotropy in the as-deposited condition was strongly affected by texture as evidenced by its dependence on orientation relative to the deposition direction. Heat treatment resulted in a significant improvement in modulus of the EBF(sup 3) product to a level nearly equivalent to that for wrought IN 718 with reduced anisotropy; reduction in texture through recrystallization; and production of a more homogeneous microstructure.

  9. Intermediate Crack Induced Debonding in Concrete Beams Strengthened with CFRP Plates - An Experimental Study

    DEFF Research Database (Denmark)

    Rusinowski, Piotr Michal; Täljsten, Björn

    2009-01-01

    , ductility and even durability. Design of structural strengthening applications using externally bonded FRP composites is usually based on conventional design approaches with improvement to account for the presence and characteristics of the FRP material. Non-conventional design issues that are specific...... of the strengthening method. End-peeling has governed a large interest and several debonding models have been presented. However, interfacial peeling at flexural cracks has not attained the same focus – even though this debonding failure is most likely more common. This paper presents laboratory tests of concrete...... beams strengthened in flexure with CFRP epoxy bonded plates. Wrapping with CFRP sheets was applied in order to try to localize the failure initiation. Concrete cracking as well as debonding initiation and propagation was possible to observe with help of advanced optical measuring system and high speed...

  10. Interpretation of electron beam induced charging of oxide layers in a transistor studied using electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Ubaldi, F; Pozzi, G [Department of Physics, University of Bologna, 40127 Bologna (Italy); Kasama, T; Dunin-Borkowski, R E [Center for Electron Nanoscopy, Technical University of Denmark, Lyngby (Denmark); McCartney, M R [Department of Physics, Arizona State University, Tempe, AZ 85287-1504 (United States); Newcomb, S B, E-mail: ubaldi@bo.imm.cnr.i [Sonsam Limited, Glebe Laboratories, Newport, Co. Tipperary (Ireland)

    2010-02-01

    Off-axis electron holography has been used to characterize a linear array of transistors, which was prepared for examination in cross-sectional geometry in the transmission electron microscope using focused ion beam milling. In reconstructed phase images, regions of silicon oxide that are located between metal contacts show unexpected elliptical phase contours centered several hundreds of nm from the specimen edge. The experimental images are compared with simulations performed using three-dimensional calculations of the electrostatic potential inside and outside the specimen, which take into account the mean inner potential of the specimen and the perturbed vacuum reference wave. The simulations suggest that the oxide layers contain a uniform volume density of positive charge and that the elliptical contours result from the combined effect of the electrostatic potential in the specimen and the external electrostatic fringing field.

  11. Unveiling the optical properties of a metamaterial synthesized by electron-beam-induced deposition

    CERN Document Server

    Woźniak, Paweł; Brönstrup, Gerald; Banyer, Peter; Christiansen, Silke; Leuchs, Gerd

    2015-01-01

    The direct writing using a focused electron beam allows for fabricating truly three-dimensional structures of sub-wavelength dimensions in the visible spectral regime. The resulting sophisticated geometries are perfectly suited for studying light-matter interaction at the nanoscale. Their overall optical response will strongly depend not only on geometry but also on the optical properties of the deposited material. In case of the typically used metal-organic precursors, the deposits show a substructure of metallic nanocrystals embedded in a carbonaceous matrix. Since gold-containing precursor media are especially interesting for optical applications, we experimentally determine the effective permittivity of such an effective material. Our experiment is based on spectroscopic measurements of planar deposits. The retrieved permittivity shows a systematic dependence on the gold particle density and cannot be sufficiently described using the common Maxwell-Garnett approach for effective medium.

  12. Changes in the chemical structure of polytetrafluoroethylene induced by electron beam irradiation in the molten state

    CERN Document Server

    Lappan, U; Lunkwitz, K

    2000-01-01

    Polytetrafluoroethylene (PTFE) was exposed to electron beam radiation at elevated temperature above the melting point under nitrogen atmosphere and in vacuum for comparison. Fourier-transform infrared (FTIR) spectroscopy was used to study the changes in the chemical structure. The irradiation under nitrogen atmosphere leads to the same structures as described recently for PTFE irradiated in vacuum. Trifluoromethyl branches and double bond structures were detected. The concentrations of terminal and internal double bonds are higher after irradiation under nitrogen than in vacuum. Annealing experiments have shown that the thermal oxidative stability of the radiation-modified PTFE is reduced compared to unirradiated PTFE. The reason are the formation of unstable structures such as double bonds.

  13. Microstructure Analysis of HPb59-1 Brass Induced by High Current Pulsed Electron Beam

    Science.gov (United States)

    Lyu, Jike; Gao, Bo; Hu, Liang; Lu, Shuaidan; Tu, Ganfeng

    2016-08-01

    In this paper, the effects of high current pulsed electron beam (HCPEB) on the microstructure evolution of casting HPb59-1 (Cu 57.1 mass%, Pb 1.7 mass% and Zn balance) alloy were investigated. The results showed a "wavy" surface which was formed with Pb element existing in the forms of stacking block and microparticles on the top surface layer after treatment. Nanocrystalline structures including Pb grains and two phases (α and β) were formed on the top remelted layer and their sizes were all less than 100 nm. The disordered β phase was generated in the surface layer after HCPEB treatment, which is beneficial for the improvement of surface properties. Meanwhile, there was a large residual stress on the alloy surface, along with the appearance of microcracks, and the preferred orientations of grains also changed.

  14. In-beam quality assurance using induced β+ activity in hadrontherapy: a preliminary physical requirements study using Geant4

    Science.gov (United States)

    Lestand, L.; Montarou, G.; Force, P.; Pauna, N.

    2012-10-01

    Light and heavy ions particle therapy, mainly by means of protons and carbon ions, represents an advantageous treatment modality for deep-seated and/or radioresistant tumours. An in-beam quality assurance principle is based on the detection of secondary particles induced by nuclear fragmentations between projectile and target nuclei. Three different strategies are currently under investigation: prompt γ rays imaging, proton interaction vertex imaging and in-beam positron emission tomography. Geant4 simulations have been performed first in order to assess the accuracy of some hadronic models to reproduce experimental data. Two different kinds of data have been considered: β+-emitting isotopes and prompt γ-ray production rates. On the one hand simulations reproduce experimental β+ emitting isotopes production rates to an accuracy of 24%. Moreover simulated β+ emitting nuclei production rate as a function of depth reproduce well the peak-to-plateau ratio of experimental data. On the other hand by tuning the tolerance factor of the photon evaporation model available in Geant4, we reduce significantly prompt γ-ray production rates until a very good agreement is reached with experimental data. Then we have estimated the total amount of induced annihilation photons and prompt γ rays for a simple treatment plan of ∼1 physical Gy in a homogenous equivalent soft tissue tumour (6 cm depth, 4 cm radius and 2 cm wide). The average annihilation photons emitted during a 45 s irradiation in a 4 π solid angle are ∼2 × 106 annihilation photon pairs and 108 single prompt γ whose energy ranges from a few keV to 10 MeV.

  15. In-beam quality assurance using induced β(+) activity in hadrontherapy: a preliminary physical requirements study using Geant4.

    Science.gov (United States)

    Lestand, L; Montarou, G; Force, P; Pauna, N

    2012-10-21

    Light and heavy ions particle therapy, mainly by means of protons and carbon ions, represents an advantageous treatment modality for deep-seated and/or radioresistant tumours. An in-beam quality assurance principle is based on the detection of secondary particles induced by nuclear fragmentations between projectile and target nuclei. Three different strategies are currently under investigation: prompt γ rays imaging, proton interaction vertex imaging and in-beam positron emission tomography. Geant4 simulations have been performed first in order to assess the accuracy of some hadronic models to reproduce experimental data. Two different kinds of data have been considered: β(+)-emitting isotopes and prompt γ-ray production rates. On the one hand simulations reproduce experimental β(+) emitting isotopes production rates to an accuracy of 24%. Moreover simulated β(+) emitting nuclei production rate as a function of depth reproduce well the peak-to-plateau ratio of experimental data. On the other hand by tuning the tolerance factor of the photon evaporation model available in Geant4, we reduce significantly prompt γ-ray production rates until a very good agreement is reached with experimental data. Then we have estimated the total amount of induced annihilation photons and prompt γ rays for a simple treatment plan of ∼1 physical Gy in a homogenous equivalent soft tissue tumour (6 cm depth, 4 cm radius and 2 cm wide). The average annihilation photons emitted during a 45 s irradiation in a 4 π solid angle are ∼2 × 10(6) annihilation photon pairs and 10(8) single prompt γ whose energy ranges from a few keV to 10 MeV.

  16. Preliminary study about frequencies of unstable chromosome alterations induced by gamma beam and neutron-gamma mixed field

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Mariana E.; Souza, Priscilla L.G.; Brandao, Jose Odinilson de C.; Santos, Joelan A.L.; Vilela, Eudice C.; Lima, Fabiana F. [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Calixto, Merilane S.; Santos, Neide [Universidade Federal de Pernanmbuco (CCB/UFPE), Recife, PE (Brazil). Centro de Ciencias Biologicas. Dept. de Genetica

    2011-07-01

    The estimate on approximate dose in exposed individual can be made through conventional cytogenetic analysis of dicentric, this technique has been used to support physical dosimetry. It is important to estimate the absorbed dose in case of accidents with the aim of developing an appropriate treatment and biological dosimetry can be very useful in case where the dosimetry is unavailable. Exposure to gamma and neutron radiation leads to the same biological effects such as chromosomal alterations and cancer. However, neutrons cause more genetic damage, such as mutation or more structural damage, such as chromosome alterations. The aim of research is to compare frequencies of unstable chromosome alterations induced by a gamma beam with those from neutron-gamma mixed field. Two blood samples were obtained from one healthy donor and irradiated at different sources. The first sample was exposed to mixed field neutron-gamma sources {sup 241}AmBe at the Neutron Calibration Laboratory (NCL - CRCN/NE - PE - Brazil) and the second one was exposed to {sup 137}Cs gamma rays at {sup 137}Cs Laboratory (CRCN/NE - PE - Brazil), both exposures resulting in an absorbed dose of 0.66Gy. Mitotic metaphase cells were obtained by lymphocyte culture for chromosomal analysis and slides were stained with Giemsa 5%. These preliminary results showed a similarity in associated dicentrics frequency per cell (0.041 and 0.048) after {sup 137}Cs and {sup 241}AmBe sources irradiations, respectively. However, it was not observed centric rings frequency per cell (0.0 and 0.027). This study will be continue to verify the frequencies of unstable chromosome alterations induced by only gamma beam and neutron-gamma mixed field. (author)

  17. Electron beam-induced immobilization of laccase on porous supports for waste water treatment applications.

    Science.gov (United States)

    Jahangiri, Elham; Reichelt, Senta; Thomas, Isabell; Hausmann, Kristin; Schlosser, Dietmar; Schulze, Agnes

    2014-08-08

    The versatile oxidase enzyme laccase was immobilized on porous supports such as polymer membranes and cryogels with a view of using such biocatalysts in bioreactors aiming at the degradation of environmental pollutants in wastewater. Besides a large surface area for supporting the biocatalyst, the aforementioned porous systems also offer the possibility for simultaneous filtration applications in wastewater treatment. Herein a "green" water-based, initiator-free, and straightforward route to highly reactive membrane and cryogel-based bioreactors is presented, where laccase was immobilized onto the porous polymer supports using a water-based electron beam-initiated grafting reaction. In a second approach, the laccase redox mediators 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and syringaldehyde were cross-linked instead of the enzyme via electron irradiation in a frozen aqueous poly(acrylate) mixture in a one pot set-up, yielding a mechanical stable macroporous cryogel with interconnected pores ranging from 10 to 50 µm in size. The membranes as well as the cryogels were characterized regarding their morphology, chemical composition, and catalytic activity. The reactivity towards waste- water pollutants was demonstrated by the degradation of the model compound bisphenol A (BPA). Both membrane- and cryogel-immobilized laccase remained highly active after electron beam irradiation. Apparent specific BPA removal rates were higher for cryogel- than for membrane-immobilized and free laccase, whereas membrane-immobilized laccase was more stable with respect to maintenance of enzymatic activity and prevention of enzyme leakage from the carrier than cryogel-immobilized laccase. Cryogel-immobilized redox mediators remained functional in accelerating the laccase-catalyzed BPA degradation, and especially ABTS was found to act more efficiently in immobilized than in freely dissolved state.

  18. Electron Beam-Induced Immobilization of Laccase on Porous Supports for Waste Water Treatment Applications

    Directory of Open Access Journals (Sweden)

    Elham Jahangiri

    2014-08-01

    Full Text Available The versatile oxidase enzyme laccase was immobilized on porous supports such as polymer membranes and cryogels with a view of using such biocatalysts in bioreactors aiming at the degradation of environmental pollutants in wastewater. Besides a large surface area for supporting the biocatalyst, the aforementioned porous systems also offer the possibility for simultaneous filtration applications in wastewater treatment. Herein a “green” water-based, initiator-free, and straightforward route to highly reactive membrane and cryogel-based bioreactors is presented, where laccase was immobilized onto the porous polymer supports using a water-based electron beam-initiated grafting reaction. In a second approach, the laccase redox mediators 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS and syringaldehyde were cross-linked instead of the enzyme via electron irradiation in a frozen aqueous poly(acrylate mixture in a one pot set-up, yielding a mechanical stable macroporous cryogel with interconnected pores ranging from 10 to 50 µm in size. The membranes as well as the cryogels were characterized regarding their morphology, chemical composition, and catalytic activity. The reactivity towards waste- water pollutants was demonstrated by the degradation of the model compound bisphenol A (BPA. Both membrane- and cryogel-immobilized laccase remained highly active after electron beam irradiation. Apparent specific BPA removal rates were higher for cryogel- than for membrane-immobilized and free laccase, whereas membrane-immobilized laccase was more stable with respect to maintenance of enzymatic activity and prevention of enzyme leakage from the carrier than cryogel-immobilized laccase. Cryogel-immobilized redox mediators remained functional in accelerating the laccase-catalyzed BPA degradation, and especially ABTS was found to act more efficiently in immobilized than in freely dissolved state.

  19. Luminescent materials and their applications

    CERN Document Server

    Virk, Hardev Singh

    2015-01-01

    It is pertinent to note that Luminescence phenomenon has once again occupied a central stage with the announcement of Nobel Prize in October 2014 to three Japanese scientists. The discovery of Galium Nitride proved to be a revolutionary step forward in creation of Blue LEDs. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources. The Volume under reference consists of 9 Chapters, written by experts in the area of Luminescent Materials. First 5 Chapters are contributed as Review Papers and the last 4 are based on Research Papers.Chapter

  20. Decreasing luminescence lifetime of evaporating phosphorescent droplets

    Science.gov (United States)

    van der Voort, D. D.; Dam, N. J.; Sweep, A. M.; Kunnen, R. P. J.; van Heijst, G. J. F.; Clercx, H. J. H.; van de Water, W.

    2016-12-01

    Laser-induced phosphorescence has been used extensively to study spray dynamics. It is important to understand the influence of droplet evaporation in the interpretation of such measurements, as it increases luminescence quenching. By suspending a single evaporating n-heptane droplet in an acoustic levitator, the properties of lanthanide-complex europium-thenoyltrifluoroacetone-trioctylphosphine oxide (Eu-TTA-TOPO) phosphorescence are determined through high-speed imaging. A decrease was found in the measured phosphorescence decay coefficient (780 → 200 μs) with decreasing droplet volumes (10-9 → 10-11 m3) corresponding to increasing concentrations (10-4 → 10-2 M). This decrease continues up to the point of shell-formation at supersaturated concentrations. The diminished luminescence is shown not to be attributable to triplet-triplet annihilation, quenching between excited triplet-state molecules. Instead, the pure exponential decays found in the measurements show that a non-phosphorescent quencher, such as free TTA/TOPO, can be attributable to this decay. The concentration dependence of the phosphorescence lifetime can therefore be used as a diagnostic of evaporation in sprays.

  1. Influence of cations and anions on the induction of cell density-independent luminescence in Photorhabdus luminescens.

    Science.gov (United States)

    Tabei, Yosuke; Ogawa, Akane; Era, Mariko; Ninomiya, Junko; Morita, Hiroshi

    2013-03-01

    Bioluminescence is emitted by various living organisms, including bacteria. While the induction mechanism in marine luminescent bacteria, such as Vibrio fischeri and V. harveyi, has been well characterized, this mechanism has not been studied in detail in the non-marine luminescent bacterium Photorhabdus luminescens. Therefore, we investigated the effect of cations and anions on the induction of luminescence by P. luminescens. Cultivation of cells in an inorganic salts solution (ISS) containing KCl, CaCl2 , MgCl2 , NaHCO3 , and MgSO4 resulted in a rapid increase in luminescence intensity. Moreover, the induction of luminescence in the ISS medium was not dependent on cell density, since cell densities remained unchanged during 48 h. Furthermore, we found that compounds containing K(+) , Mg(2+) , and HCO3(-) were necessary to induce cell density-independent luminescence. The intensity of luminescence per cell cultured in medium containing KCl, MgCl2 , and NaHCO3 was approximately 100-fold higher than that cultured in NB. In contrast, when cells actively grew in normal growth condition, the intensity of luminescence per cell was not increased even in the presence of K(+) , Mg(2+) , and HCO3(-) . Thus, these results suggest that the luminescence of P. luminescens is regulated by 2 independent cell density-dependent and -independent mechanisms.

  2. Low current beam techniques

    Energy Technology Data Exchange (ETDEWEB)

    Saint, A.; Laird, J.S.; Bardos, R.A.; Legge, G.J.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Nishijima, T.; Sekiguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan).

    1993-12-31

    Since the development of Scanning Transmission Microscopy (STIM) imaging in 1983 many low current beam techniques have been developed for the scanning (ion) microprobe. These include STIM tomography, Ion Beam Induced Current, Ion Beam Micromachining and Microlithography and Ionoluminense. Most of these techniques utilise beam currents of 10{sup -15} A down to single ions controlled by beam switching techniques This paper will discuss some of the low beam current techniques mentioned above, and indicate, some of their recent applications at MARC. A new STIM technique will be introduced that can be used to obtain Z-contrast with STIM resolution. 4 refs., 3 figs.

  3. Multicolored luminescent CdS nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The observation of efficient blue, green, orange and red luminescence from CdS nanocrystals made by using a reverse micelle method was reported. The blue luminescence about 480 nm is attributed to the radiative recombination of electron-hole pairs.The red luminescence around 650 nm is due to the radiative recombination of the exciton trapped in the nanocrystal surface defect states. The combination of different portion of band-edge emission and surface trap state emission results in green and orange luminescence for the nanocrystals. The CdS nanocrystals with efficient multicolored luminescence may find potential application in full color displays and biolabelings.

  4. Luminescence in the fluoride-containing phosphate-based glasses: A possible origin of their high resistance to nanosecond pulse laser-induced damage

    Science.gov (United States)

    Wang, Pengfei; Lu, Min; Gao, Fei; Guo, Haitao; Xu, Yantao; Hou, Chaoqi; Zhou, Zhiwei; Peng, Bo

    2015-02-01

    Fusion power offers the prospect of an almost inexhaustible source of energy for future generations. It was reported that fusion fuel gains exceeding unity on the National Ignition Facility (NIF) were achieved, but so far great deal of scientific and engineering challenges have to be overcome for realizing fusion power generation. There is a bottleneck for color-separation gratings in NIF and other similar inertial confinement fusion (ICF) lasers. Here we show a series of high performance phosphate-based glasses that can transmit the third harmonic frequency (3ω) laser light with high efficiency meanwhile filter the fundamental (1ω) and the second harmonic frequency (2ω) laser lights through direct absorption, and especially they exhibit excellent damage threshold induced by nanosecond pulse laser compared with that of the fused silica used in NIF. Yellowish-orange fluorescence emits during the laser-material interaction process, and it can be tailored through regulating the glass structure. Study on its structural origin suggests that the fluorescence emission is a key factor that conduces to the high laser-induced damage resistance of these glasses. The results also indicated the feasibility of utilizing these high performance glasses in novel color separation optics, allowing novel design for the final optics assembly in ICF lasers.

  5. Luminescence in the fluoride-containing phosphate-based glasses: a possible origin of their high resistance to nanosecond pulse laser-induced damage.

    Science.gov (United States)

    Wang, Pengfei; Lu, Min; Gao, Fei; Guo, Haitao; Xu, Yantao; Hou, Chaoqi; Zhou, Zhiwei; Peng, Bo

    2015-02-26

    Fusion power offers the prospect of an almost inexhaustible source of energy for future generations. It was reported that fusion fuel gains exceeding unity on the National Ignition Facility (NIF) were achieved, but so far great deal of scientific and engineering challenges have to be overcome for realizing fusion power generation. There is a bottleneck for color-separation gratings in NIF and other similar inertial confinement fusion (ICF) lasers. Here we show a series of high performance phosphate-based glasses that can transmit the third harmonic frequency (3ω) laser light with high efficiency meanwhile filter the fundamental (1ω) and the second harmonic frequency (2ω) laser lights through direct absorption, and especially they exhibit excellent damage threshold induced by nanosecond pulse laser compared with that of the fused silica used in NIF. Yellowish-orange fluorescence emits during the laser-material interaction process, and it can be tailored through regulating the glass structure. Study on its structural origin suggests that the fluorescence emission is a key factor that conduces to the high laser-induced damage resistance of these glasses. The results also indicated the feasibility of utilizing these high performance glasses in novel color separation optics, allowing novel design for the final optics assembly in ICF lasers.

  6. Zeeman Electromagnetically Induced Transparency with crossed pump and probe beams: Small angle dependence

    Science.gov (United States)

    Campbell, Kaleb; Madkhaly, Samaya; de Medeiros, Dillon; Bali, Samir; Macklin Quantum Information Sciences Collaboration

    2016-05-01

    Progress toward undergraduate oriented experiments on image storage in room-temperature atomic vapor using Electromagnetically Induced Transparency is described. Using a scanning longitudinal magnetic field technique we diagnose and suppress stray magnetic fields and polarization impurity. We consider the pump-probe angular dependence of the EIT signal but at much smaller angles of less than a milliradian.

  7. Analyses on Radiation Effects in Solid Amino Acids Induced by Low Energy Fe~+ Ion Beams

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Radiation effects in Solid samples of L(+)-cysteine and L(+)-cysteine hydroehloride monohydrate induced by 110 keV Fe~+ion implantation were characterized with FTIR, ESR,HPLC and ESI-FTMS.It was validated that solid samples of the irradiated amino acids were damaged to a certain extent,and some new groups or molecular products formed.

  8. Experimental setup and first measurement of DNA damage induced along and around an antiproton beam

    DEFF Research Database (Denmark)

    Kavanagh, J. N.; Currell, F. J.; Timson, D. J.;

    2010-01-01

    Radiotherapy employs ionizing radiation to induce lethal DNA lesions in cancer cells while minimizing damage to healthy tissues. Due to their pattern of energy deposition, better therapeutic outcomes can, in theory, be achieved with ions compared to photons. Antiprotons have been proposed to offe...

  9. SU-E-T-211: Induced Release of Nanocarrier Encapsulated Chemotherapeutic Drugs Using Proton Radiotherapy Beams

    Energy Technology Data Exchange (ETDEWEB)

    Polf, J; Jackson, I [University of Maryland School of Medicine, Baltimore, MD (United States); Ranjan, A; Fernando, R [Oklahoma State University, Stillwater, OK (United States); Zheng, Y [Procure Proton Therapy Center, Oklahoma City, OK (United States)

    2014-06-01

    Purpose: The purpose of this work was to develop and validate an open source independent MU dose calculation software for S and S IMRT based in the algorithm proposed by Kung et.al. Methods: Treatment plans were done using Iplan v4.5 BrainLAB TPS and S and S IMRT modality. A 6MV photon beam produced by a Primus linear accelerator equipped with an Optifocus MLC was used. TPS dose calculation algorithms were pencil beam and Monte Carlo. 230 IMRT treatments plans were selected for the study. The software was written under MALTLAB environment. Treatment plans were imported by the software using RTP format. Field fluences were reconstructed adding all segments.The algorithm implemented in the software calculates the dose at a reference point as the sum of primary and scatter dose. The primary dose is obtained by masking the fluence map with a circle of radius 1cm. The scatter dose is obtained through a shaped ring mask around the previous circle with a thickness of 0.5cm; the rings are increased one after another with constant thickness until cover the entire map of influence. The dosimetric parameters Sc, Sp and TPR vary depending on radio, the transmission effect of the MLC, inverse square law and dose profile are used for the calculation. Results: The average difference between measured and independent calculated dose was 0.4% ± 2.2% [−6.8%, 6.4%]. For 91% of the studied plans the difference was less than 3%. The difference between the measured and TPS dose with pencilbeam algorithm was 2.6% ± 1.41% [−2.0%, 5.6%] and Monte Carlo algorithm was 0.4% ± 1.5% [−4.9%, 3.7%]. The differences obtained are comparable to that obtained with the ionization chamber and TPS. Conclusion: The developed software is suitable for use in S and S IMRT dose calculation. This application is open and can be downloading under request.

  10. The new external microbeam facility at the 5 MV Tandetron accelerator laboratory in Madrid: beam characterisation and first results

    Energy Technology Data Exchange (ETDEWEB)

    Enguita, Olga E-mail: olga.enguita@uam.es; Fernandez-Jimenez, M.T.; Garcia, G.; Climent-Font, A.; Calderon, T.; Grime, G.W

    2004-06-01

    This paper describes the new external microbeam on the 15 deg. beamline of the 5 MV Tandetron accelerator recently installed at the CMAM in Madrid. The focusing and beam extraction system was supplied by Oxford Microbeams Ltd. and consists of a high precision quadrupole doublet with an interchangeable Kapton window exit nozzle and front-viewing video microscope. The sample is positioned in the beam using a stepper motor stage. The beam current and beam profile have been determined under different experimental conditions. A simple method based on the signal processing of ion-induced luminescence from quartz targets has been used to determine the beam profile in two dimensions simultaneously, without scanning. This is the first step in the development of a real time beam profile monitoring system, which could be used as part of an automated beam focusing procedure. The beam line will be primarily devoted to archaeometry and cultural heritage studies. As an example we report the characterisation of two Tang appearance antique porcelains.

  11. Determination of Kinetic Parameters and Metal Ions in Urea-Urease System Based on the Biochemical Reaction Heat Induced Laser Beam Deflection

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new analytical method for the determination of urea-urease system based on biochemical reaction heat induced laser beam deflection is presented in this paper. With the method, the Michaelis constant (Km) of urease and apparent inhibition constant (Ki) of some metal ion inhibitors were measured respectively. This method was also used for the quantitative determination of metal ions with satisfactory result.

  12. TH-C-17A-09: Direct Visualization and Monitoring of Medical Radiation Beams in Air

    Energy Technology Data Exchange (ETDEWEB)

    Fahimian, B; Ceballos, A; Turkcan, S; Kapp, D; Pratx, G [Stanford University, Stanford, CA (United States)

    2014-06-15

    Purpose: Radiation therapy errors are rare but potentially catastrophic. Recent fatal incidents could have been avoided by utilizing real-time methods of monitoring delivery of radiation during treatment. However, few existing methods are practical enough to be used routinely. The study presents the first experimental demonstration of a novel non-perturbing method of monitoring radiation therapy through the phenomena of air scintillation. Methods: Monitoring of radiation delivery was devised by leveraging the phenomena of nitrogen excitation in air by ionizing radiation. The excitation induced weak luminescence in the 300–400 nm range, a process called air scintillation. An electron-multiplication charge-coupled device camera (f/0.95 lens; 440 nm shortpass) was set-up in a clinical treatment vault and was used to capture air scintillation images of kilovoltage and megavoltage beams. Monte Carlo simulations were performed to determine the correlation of radiation dose to air scintillation. Results: Megavoltage beams from a Varian Clinac 21EX and kilovoltage beams from an orthovoltage unit (50 kVp, 30 mA) were visualized with a relatively short exposure time (10 s). Cherenkov luminescence produced in a plastic transparent phantom did not interfere with detection of air scintillation. The image intensity displayed an inverse intensity falloff (r{sup 2} = 0.89) along the central axis and was proportional to dose rate (r{sup 2} = 0.9998). As beam energy increased, the divergence of the imaged beam decreased. Last, air scintillation was visualized during a simulated total skin irradiation electron treatment. Conclusion: Air scintillation can be clinically detected to monitor a radiation beam in an inexpensive and non-perturbing manner. This new method is advantageous in monitoring for gross delivery and uniquely capable of wide area in a single acquisition, such as the case for online verification of total body / skin / lymphoid irradiation treatments.

  13. Measurement of air and nitrogen fluorescence light yields induced by electron beam for UHECR experiments

    CERN Document Server

    Colin, P; Grebenyuk, V; Naumov, D; Nédélec, P; Nefedov, Y; Onofre, A; Porokhovoi, S; Sabirov, B; Tkatchev, L G

    2006-01-01

    Most of the Ultra High Energy Cosmic Ray (UHECR) experiments and projects (HiRes, AUGER, TA, EUSO, TUS,...) use air fluorescence to detect and measure extensive air showers (EAS). The precise knowledge of the Fluorescence Light Yield (FLY) is of paramount importance for the reconstruction of UHECR. The MACFLY - Measurement of Air Cherenkov and Fluorescence Light Yield - experiment has been designed to perform such FLY measurements. In this paper we will present the results of FLY in the 290-440 nm wavelength range for dry air and pure nitrogen, both excited by electrons with energy of 1.5 MeV, 20 GeV and 50 GeV. The experiment uses a 90Sr radioactive source for low energy measurement and a CERN SPS electron beam for high energy. We find that the FLY is proportional to the deposited energy (E_d) in the gas and we show that the air fluorescence properties remain constant independently of the electron energy. At the reference point: atmospheric dry air at 1013 hPa and 23C, the ratio FLY/E_d=17.6 photon/MeV with ...

  14. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Science.gov (United States)

    SCHWARTZ, João Paulo; RAVELI, Taísa Boamorte; ALMEIDA, Kélei Cristina de Mathias; SCHWARTZ-FILHO, Humberto Osvaldo; RAVELI, Dirceu Barnabé

    2015-01-01

    Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT). Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years) with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0) and after Herbst treatment (T1). All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%. Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders. Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance. PMID:26537718

  15. Fabrication of SiGe quantum devices by electron-beam induced damage

    Science.gov (United States)

    Ryan, Joseph M.; Broers, Alec N.; Paul, Douglas J.; Pepper, Michael; Whall, Terry E.; Fernández, Juan M.; Joyce, Bruce A.

    1997-01-01

    The effects of electron beam irradiation damage has been investigated in Si/SiGe heterostructures. The damage to SiGe two-dimensional hole gases (2DHGs) was measured as a function of accelerating voltage and electron dose. For 40 keV electrons at a dose of 2 Cm-2(typical PMMA resist values), the material properties were not significantly altered. For 100 keV and higher energy electrons, the irradiated material became more resistive at 300 K as the electron energies were increased. The material became highly resistive at low temperatures and froze out at between 20 and 30 K. The 2DHGs also became more resistive at 300 K when the irradiation dose was increased. A number of narrow channel devices were fabricated on high mobility SiGe two-dimensional electron gases (2DEGs) using the damage technique and gated using Schottky gates. Plateaux were observed in the conductance as a function of gate voltage. Random telegraph signals (RTSs) were observed from a 10μm-wide Hall bar irradiated with 300 keV electrons at a dose of105C m-2

  16. Cone beam computed tomography study of apical root resorption induced by Herbst appliance

    Directory of Open Access Journals (Sweden)

    João Paulo SCHWARTZ

    2015-10-01

    Full Text Available Objective This study evaluated the frequency of root resorption during the orthodontic treatment with Herbst appliance by Cone Beam Computed Tomography (CBCT.Material and Methods The sample comprised 23 patients (11 men, 12 women; mean ages 15.76±1.75 years with Class II division 1 malocclusion, treated with Herbst appliance. CBCT was obtained before treatment (T0 and after Herbst treatment (T1. All the dental roots, except third molars, were evaluated, and apical root resorption was determined using the axial guided navigation method. Paired t-tests and Wilcoxon T Test were used to compare the dependent samples in parametric and nonparametric cases, respectively. Chi-Square Test with Yates’ correction was used to evaluate the relationship between apical root resorption and gender. Results were considered at a significance level of 5%.Results Apical resorption was detected by CBCT in 57.96% of 980 roots that underwent Herbst appliance treatment. All patients had minimal resorption and there was no statistical significance between the genders.Conclusion CBCT three-dimensional evaluation showed association between Herbst appliance and minimal apical root resorption, mostly in the anchoring teeth, without clinical significance.

  17. Effects of Ion Irradiation on Seedlings Growth Monitored by Ultraweak Delayed Luminescence

    Science.gov (United States)

    Abe, Tomoko; Cirrone, Giuseppe A. P.; Cuttone, Giacomo; Gulino, Marisa; Musumeci, Francesco; Romano, Francesco; Ryuto, Hiromichi; Scordino, Agata

    2016-01-01

    The optical technique based on the measurement of delayed luminescence emitted from the biological samples has demonstrated its ability to provide valid and predictive information on the functional status of various biological systems. We want to extend this technique to study the effect of ionizing radiation on biological systems. In particular we are interested in the action of ion beams, used for therapeutic purposes or to increase the biological diversity. In general, the assessment of the damage that radiation produces both in the target objects and in the surrounding tissues, requires considerable time because is based on biochemical analysis or on the examination of the evolution of the irradiated systems. The delayed luminescence technique could help to simplify this investigation. We have so started our studies performing irradiations of some relatively simple vegetable models. In this paper we report results obtained from mung bean (Vigna radiata) seeds submitted to a 12C ion beam at the energy of 62 MeV/nucleon. The dry seeds were irradiated at doses from 50 to 7000 Gy. The photoinduced delayed luminescence of each seed before and after ion irradiation was measured. The growth of seedlings after irradiation was compared with that of untreated seeds. A growth reduction on increasing the dose was registered. The results show strong correlations between the ion irradiation dose, seeds growth and delayed luminescence intensity. In particular, the delayed luminescence intensity is correlated by a logistic function to the seedlings elongation and, after performing a suitable measurement campaign based on blind tests, it could become a tool able to predict the growth of seeds after ion irradiation. Moreover these results demonstrate that measurements of delayed luminescence could be used as a fast and non-invasive technique to check the effects of ion beams on relatively simple biological systems. PMID:27936220

  18. Controlling plasmon-enhanced luminescence

    NARCIS (Netherlands)

    Mertens, H.

    2007-01-01

    Plasmons are collective oscillations of the free electrons in a metal or an ionized gas. Plasmons dominate the optical properties of noble-metal nanoparticles, which enables a variety of applications. This thesis focuses on plasmon-enhanced luminescence of silicon quantum dots (Si QDs) and optically

  19. Simulation of ion beam induced current in radiation detectors and microelectronic devices.

    Energy Technology Data Exchange (ETDEWEB)

    Vizkelethy, Gyorgy

    2009-10-01

    Ionizing radiation is known to cause Single Event Effects (SEE) in a variety of electronic devices. The mechanism that leads to these SEEs is current induced by the radiation in these devices. While this phenomenon is detrimental in ICs, this is the basic mechanism behind the operation of semiconductor radiation detectors. To be able to predict SEEs in ICs and detector responses we need to be able to simulate the radiation induced current as the function of time. There are analytical models, which work for very simple detector configurations, but fail for anything more complex. On the other end, TCAD programs can simulate this process in microelectronic devices, but these TCAD codes costs hundreds of thousands of dollars and they require huge computing resources. In addition, in certain cases they fail to predict the correct behavior. A simulation model based on the Gunn theorem was developed and used with the COMSOL Multiphysics framework.

  20. Ion Beam Induced Charge Collection (IBICC) from Integrated Circuit Test Structures Using a 10 MeV Carbon Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Aton, T.J.; Doyle, B.L.; Duggan, J.L.; El Bouanani, M.; Guo, B.N.; McDaniel, F.D.; Renfrow, S.N.; Walsh, D.S.

    1998-11-18

    As future sizes of Integrated Circuits (ICs) continue to shrink the sensitivity of these devices, particularly SRAMs and DRAMs, to natural radiation is increasing. In this paper, the Ion Beam Induced Charge Collection (IBICC) technique is utilized to simulate neutron-induced Si recoil effects in ICS. The IBICC measurements, conducted at the Sandia National Laboratories employed a 10 MeV carbon microbeam with 1pm diameter spot to scan test structures on specifically designed ICS. With the aid of layout information, an analysis of the charge collection efficiency from different test areas is presented. In the present work a 10 MeV Carbon high-resolution microbeam was used to demonstrate the differential charge collection efficiency in ICS with the aid of the IC design Information. When ions strike outside the FET, the charge was only measured on the outer ring, and decreased with strike distance from this diode. When ions directly strike the inner and ring diodes, the collected charge was localized to these diodes. The charge for ions striking the gate region was shared between the inner and ring diodes. I The IBICC measurements directly confirmed the interpretations made in the earlier work.

  1. New Opportunities for Lanthanide Luminescence

    Institute of Scientific and Technical Information of China (English)

    Jean-Claude G. Bünzli; Steve Comby; Anne-Sophie Chauvin; Caroline D. B. Vandevyver

    2007-01-01

    Trivalent lanthanide ions display fascinating optical properties. The discovery of the corresponding elements and their first industrial uses were intimately linked to their optical properties. This relationship has been kept alive until today when many high-technology applications of lanthanide-containing materials such as energy-saving lighting devices, displays, optical fibers and amplifiers, lasers, responsive luminescent stains for biomedical analyses and in cellulo sensing and imaging, heavily rely on the brilliant and pure-color emission of lanthanide ions. In this review we first outlined the basics of lanthanide luminescence with emphasis on f-f transitions, the sensitization mechanisms, and the assessment of the luminescence efficiency of lanthanide-containing emissive molecular edifices. Emphasis was then put on two fast developing aspects of lanthanide luminescence: materials for telecommunications and light emitting diodes, and biomedical imaging and sensing. Recent advances in NIR-emitting materials for plastic amplifiers and waveguides were described, together with the main solutions brought by researchers to minimize non-radiative deactivation of excited states. The demonstration in 1999 that erbium tris(8-hydroxyquinolinate) displayed a bright green emission suitable for organic light emitting diodes (OLEDs) was followed by realizing that in OLEDs, 25% of the excitation energy leads to singlet states and 75% to triplet states. Since lanthanide ions are good triplet quenchers, they now also play a key role in the development of these lighting devices. Luminescence analyses of biological molecules are among the most sensitive analytical techniques known. The long lifetime of the lanthanide excited states allows time-resolved spectroscopy to be used, suppressing the sample autofluorescence and reaching very low detection limits. Not only visible lanthanide sensors are now ubiquitously provided in medical diagnosis and in cell imaging, but the

  2. Surface-acoustic-wave-driven luminescence from a lateral p-n junction

    Science.gov (United States)

    Gell, J. R.; Atkinson, P.; Bremner, S. P.; Sfigakis, F.; Kataoka, M.; Anderson, D.; Jones, G. A. C.; Barnes, C. H. W.; Ritchie, D. A.; Ward, M. B.; Norman, C. E.; Shields, A. J.

    2006-12-01

    The authors report surface-acoustic-wave-driven luminescence from a lateral p-n junction formed by molecular beam epitaxy regrowth of a modulation doped GaAs /AlGaAs quantum well on a patterned GaAs substrate. Surface-acoustic-wave-driven transport is demonstrated by peaks in the electrical current and light emission from the GaAs quantum well at the resonant frequency of the transducer. This type of junction offers high carrier mobility and scalability. The demonstration of surface-acoustic-wave luminescence is a significant step towards single-photon applications in quantum computation and quantum cryptography.

  3. Beam-loss induced pressure rise of Large Hadron Collider collimator materials irradiated with 158 GeV/u $In^{49+}$ ions at the CERN Super Proton Synchrotron

    CERN Document Server

    Mahner, Edgar; Hansen, Jan; Page, Eric; Vincke, H

    2004-01-01

    During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 10/sup 4/ to 10/sup 7/ molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for Large Hadron Collider (LHC) ion operation. In 2003, a desorption experiment was installed at the super proton synchrotron to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN (low carbon with nitrogen) stainless steel were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental ...

  4. Beam-Loss Induced Pressure Rise of LHC Collimator Materials Irradiated with 158 GeV/u $In^{49+}$ Ions at the CERN SPS

    CERN Document Server

    Mahner, Edgar; Hansen, Jan; Page, Eric; Vincke, Helmut H

    2004-01-01

    During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 1044 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measure-ment of heavy-ion induced molecular desorption in the GeV/u energy range is important for LHC ion operation. In 2003, a desorption experiment was installed at the SPS to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN stainless steel, were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental set-up, the results of the pressure rise measurements are presented, and the deri...

  5. Beam-loss induced pressure rise of Large Hadron Collider collimator materials irradiated with 158 GeV/u In49+ ions at the CERN Super Proton Synchrotron

    Science.gov (United States)

    Mahner, E.; Efthymiopoulos, I.; Hansen, J.; Page, E.; Vincke, H.

    2004-10-01

    During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 104 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for Large Hadron Collider (LHC) ion operation. In 2003, a desorption experiment was installed at the Super Proton Synchrotron to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316LN (low carbon with nitrogen) stainless steel were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental setup, the results of the pressure rise measurements are presented, and the derived desorption yields are compared with data from other experiments.

  6. Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

    Science.gov (United States)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arduini, G.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barranco Navarro, L.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez, J.; Benitez Garcia, J. 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G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2016-05-01

    This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown; in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β* are studied.

  7. Thermally induced formation of metastable nanocomposites in amorphous Cr-Zr-O thin films deposited using reactive ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Rafaja, David, E-mail: rafaja@ww.tu-freiberg.de [Institute of Materials Science, Freiberg University of Technology, D-09599 Freiberg (Germany); Wüstefeld, Christina [Institute of Materials Science, Freiberg University of Technology, D-09599 Freiberg (Germany); Abrasonis, Gintautas [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Braeunig, Stefan [Institute of Materials Science, Freiberg University of Technology, D-09599 Freiberg (Germany); Baehtz, Carsten [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Hanzig, Florian; Dopita, Milan [Institute of Materials Science, Freiberg University of Technology, D-09599 Freiberg (Germany); Krause, Matthias [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Gemming, Sibylle [Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, D-01314 Dresden (Germany); Institute of Physics, Technische Universität Chemnitz, D-09126 Chemnitz (Germany)

    2016-08-01

    Successive crystallization of amorphous Cr-Zr-O thin films, formation of the (Cr,Zr){sub 2}O{sub 3}/(Zr,Cr)O{sub 2} nanocomposites and the th