WorldWideScience

Sample records for beam induced higher

  1. Beam induced RF heating

    CERN Document Server

    Salvant, B; Arduini, G; Assmann, R; Baglin, V; Barnes, M J; Bartmann, W; Baudrenghien, P; Berrig, O; Bracco, C; Bravin, E; Bregliozzi, G; Bruce, R; Bertarelli, A; Carra, F; Cattenoz, G; Caspers, F; Claudet, S; Day, H; Garlasche, M; Gentini, L; Goddard, B; Grudiev, A; Henrist, B; Jones, R; Kononenko, O; Lanza, G; Lari, L; Mastoridis, T; Mertens, V; Métral, E; Mounet, N; Muller, J E; Nosych, A A; Nougaret, J L; Persichelli, S; Piguiet, A M; Redaelli, S; Roncarolo, F; Rumolo, G; Salvachua, B; Sapinski, M; Schmidt, R; Shaposhnikova, E; Tavian, L; Timmins, M; Uythoven, J; Vidal, A; Wenninger, J; Wollmann, D; Zerlauth, M

    2012-01-01

    After the 2011 run, actions were put in place during the 2011/2012 winter stop to limit beam induced radio frequency (RF) heating of LHC components. However, some components could not be changed during this short stop and continued to represent a limitation throughout 2012. In addition, the stored beam intensity increased in 2012 and the temperature of certain components became critical. In this contribution, the beam induced heating limitations for 2012 and the expected beam induced heating limitations for the restart after the Long Shutdown 1 (LS1) will be compiled. The expected consequences of running with 25 ns or 50 ns bunch spacing will be detailed, as well as the consequences of running with shorter bunch length. Finally, actions on hardware or beam parameters to monitor and mitigate the impact of beam induced heating to LHC operation after LS1 will be discussed.

  2. Mutation induction by ion beams in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-04-01

    This review mainly describes study results obtained in the Takasaki ion-beam (IB) irradiation facility (TIARA) on the mutation induction in higher plants. Biological effects like lethality and on budding of IBs (carbon, Ne and Ar) are discussed in relation with their linear energy transfer (LET), relative biological effectiveness and the developmental states in shepherd's-purse and tobacco. Induced mutation by IB are characterized by those findings that the mutation rate by C beam is 1.9 x 10{sup -6}, being 17 times higher than the electron beam, in the shepherd's-purse, that C beam induces larger structural changes than electron beam when examined by molecular mechanism of tt and gl gene mutations, and that mutation spectrum of IB is different from that of {gamma}-ray and is wider. Novel mutants are described on shepherd's-purse (pigment mutants, ultraviolet (UV)-resistant and sensitive ones, and flowering ones), disease-resistant rice, barley and tobacco plants, and flowering plants. IB mutation is possibly useful for solving the problems of environment and foods in future. (N.I.)

  3. Higher-order harmonics of general limited diffraction Bessel beams

    International Nuclear Information System (INIS)

    Ding De-Sheng; Huang Jin-Huang

    2016-01-01

    In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m -th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. (special topic)

  4. Higher-order harmonics of general limited diffraction Bessel beams

    Science.gov (United States)

    Ding, De-Sheng; Huang, Jin-Huang

    2016-12-01

    In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m-th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. Project supported by the National Natural Science Foundation of China (Grant Nos. 11074038 and 11374051).

  5. Generating superpositions of higher order bessel beams [Conference paper

    CSIR Research Space (South Africa)

    Vasilyeu, R

    2009-10-01

    Full Text Available An experimental setup to generate a superposition of higher-order Bessel beams by means of a spatial light modulator and ring aperture is presented. The experimentally produced fields are in good agreement with those calculated theoretically....

  6. Higher harmonics generation in relativistic electron beam with virtual cathode

    Energy Technology Data Exchange (ETDEWEB)

    Kurkin, S. A., E-mail: KurkinSA@gmail.com; Badarin, A. A.; Koronovskii, A. A.; Hramov, A. E. [Saratov State Technical University, Politechnicheskaja 77, Saratov 410028, Russia and Saratov State University, Astrakhanskaja 83, Saratov 410012 (Russian Federation)

    2014-09-15

    The study of the microwave generation regimes with intense higher harmonics taking place in a high-power vircator consisting of a relativistic electron beam with a virtual cathode has been made. The characteristics of these regimes, in particular, the typical spectra and their variations with the change of the system parameters (beam current, the induction of external magnetic field) as well as physical processes occurring in the system have been analyzed by means of 3D electromagnetic simulation. It has been shown that the system under study demonstrates the tendency to the sufficient growth of the amplitudes of higher harmonics in the spectrum of current oscillations in the VC region with the increase of beam current. The obtained results allow us to consider virtual cathode oscillators as promising high power mmw-to-THz sources.

  7. Electron-beam-induced conduction in dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Acris, F C; Davies, P M; Lewis, T J [University Coll. of North Wales, Bangor (UK). School of Electronic Engineering Science

    1976-03-14

    A model for the enhanced conduction induced in dielectric films under electron bombardment while electrically stressed is discussed. It is assumed that the beam produces a virtual electrode at the end of its range in the dielectric and, as a consequence, the induced conduction is shown to depend on the properties of that part of the dielectric beyond the range of the beam. This model has also been discussed recently by Nunes de Oliviera and Gross. In the present treatment, it is shown how the model permits investigation of beam scattering and carrier generation and recombination processes. Experiments on electron-bombardment-induced conduction of thin (72 to 360 nm) films of anodic tantalum oxide are reported and it is shown that the theoretical model provides a very satisfactory explanation of all features of the results including the apparent threshold energy for enhanced conduction.

  8. Beam induced rf cavity transient voltage

    International Nuclear Information System (INIS)

    Kramer, S.L.; Wang, J.M.

    1998-10-01

    The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ω r of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω ο . The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(hω ο t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kinds of longitudinal rigid dipole mode which differs from the conventional Robinson mode

  9. Beam Induced Pressure Rise at RHIC

    CERN Document Server

    Zhang, S Y; Bai, Mei; Blaskiewicz, Michael; Cameron, Peter; Drees, Angelika; Fischer, Wolfram; Gullotta, Justin; He, Ping; Hseuh Hsiao Chaun; Huang, Haixin; Iriso, Ubaldo; Lee, Roger C; Litvinenko, Vladimir N; MacKay, William W; Nicoletti, Tony; Oerter, Brian; Peggs, Steve; Pilat, Fulvia Caterina; Ptitsyn, Vadim; Roser, Thomas; Satogata, Todd; Smart, Loralie; Snydstrup, Louis; Thieberger, Peter; Trbojevic, Dejan; Wang, Lanfa; Wei, Jie; Zeno, Keith

    2005-01-01

    Beam induced pressure rise in RHIC warm sections is currently one of the machine intensity and luminosity limits. This pressure rise is mainly due to electron cloud effects. The RHIC warm section electron cloud is associated with longer bunch spacings compared with other machines, and is distributed non-uniformly around the ring. In addition to the countermeasures for normal electron cloud, such as the NEG coated pipe, solenoids, beam scrubbing, bunch gaps, and larger bunch spacing, other studies and beam tests toward the understanding and counteracting RHIC warm electron cloud are of interest. These include the ion desorption studies and the test of anti-grazing ridges. For high bunch intensities and the shortest bunch spacings, pressure rises at certain locations in the cryogenic region have been observed during the past two runs. Beam studies are planned for the current 2005 run and the results will be reported.

  10. SRF cavity alignment detection method using beam-induced HOM with curved beam orbit

    Science.gov (United States)

    Hattori, Ayaka; Hayano, Hitoshi

    2017-09-01

    We have developed a method to obtain mechanical centers of nine cell superconducting radio frequency (SRF) cavities from localized dipole modes, that is one of the higher order modes (HOM) induced by low-energy beams. It is to be noted that low-energy beams, which are used as alignment probes, are easy to bend in fringe fields of accelerator cavities. The estimation of the beam passing orbit is important because only information about the beam positions measured by beam position monitors outside the cavities is available. In this case, the alignment information about the cavities can be obtained by optimizing the parameters of the acceleration components over the beam orbit simulation to consistently represent the position of the beam position monitors measured at every beam sweep. We discuss details of the orbit estimation method, and estimate the mechanical center of the localized modes through experiments performed at the STF accelerator. The mechanical center is determined as (x , y) =(0 . 44 ± 0 . 56 mm , - 1 . 95 ± 0 . 40 mm) . We also discuss the error and the applicable range of this method.

  11. Characterization of ion beam induced nanostructures

    International Nuclear Information System (INIS)

    Ghatak, J.; Satpati, B.; Umananda, M.; Kabiraj, D.; Som, T.; Dev, B.N.; Akimoto, K.; Ito, K.; Emoto, T.; Satyam, P.V.

    2006-01-01

    Tailoring of nanostructures with energetic ion beams has become an active area of research leading to the fundamental understanding of ion-solid interactions at nanoscale regime and with possible applications in the near future. Rutherford backscattering spectrometry (RBS), high resolution transmission electron microscopy (HRTEM) and asymmetric X-ray Bragg-rocking curve experimental methods have been used to characterize ion-induced effects in nanostructures. The possibility of surface and sub-surface/interface alloying at nano-scale regime, ion-beam induced embedding, crater formation, sputtering yield variations for systems with isolated nanoislands, semi-continuous and continuous films of noble metals (Au, Ag) deposited on single crystalline silicon will be reviewed. MeV-ion induced changes in specified Au-nanoislands on silicon substrate are tracked as a function of ion fluence using ex situ TEM. Strain induced in the bulk silicon substrate surface due to 1.5 MeV Au 2+ and C 2+ ion beam irradiation is determined by using HRTEM and asymmetric Bragg X-ray rocking curve methods. Preliminary results on 1.5 MeV Au 2+ ion-induced effects in nanoislands of Co deposited on silicon substrate will be discussed

  12. Mutation induced with ion beam irradiation in rose

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H. E-mail: yhiroya@nias.affrc.go.jp; Nagatomi, S.; Morishita, T.; Degi, K.; Tanaka, A.; Shikazono, N.; Hase, Y

    2003-05-01

    The effects of mutation induction by ion beam irradiation on axillary buds in rose were investigated. Axillary buds were irradiated with carbon and helium ion beams, and the solid mutants emerged after irradiation by repeated cutting back. In helium ion irradiation, mutations were observed in plants derived from 9 buds among 56 irradiated buds in 'Orange Rosamini' and in plants derived from 10 buds among 61 irradiated buds in 'Red Minimo'. In carbon ion, mutations were observed in plants derived from 12 buds among 88 irradiated buds in 'Orange Rosamini'. Mutations were induced not only in higher doses but also in lower doses, with which physiological effect by irradiation was hardly observed. Irradiation with both ion beams induced mutants in the number of petals, in flower size, in flower shape and in flower color in each cultivar.

  13. Beam induced heating reduction by bunch flattening

    CERN Document Server

    Argyropoulos, T; Esteban Müller, JF; Jakobsen, S; Mastoridis, T; Metral, E; Mounet, N; Papotti, G; Pieloni, T; Salvant, B; Shaposhnikova, E; Timko, H

    2014-01-01

    The main purpose of this MD was to modify the beam induced heating on some critical LHC components by flattening the bunch distribution by applying an RF phase modulation. In this way, the beam spectrum was modified so that the power spectral density is reduced at low frequencies (below 1.1 GHz), which is the band of frequencies where the beam interaction with different component impedances is most critical. We present temperature measurements showing the beneficial effect of this latter distribution on some of the monitored devices. Longitudinal peak detected Schottky spectrum was also acquired during the first part of the MD with the intention of estimating the synchrotron frequency shift due to the reactive part of the longitudinal impedance. In the second part of the MD, an attempt to cure the transverse instability during the beta-squeeze was done by reducing the RF voltage to lengthen the bunches and enhance Landau Damping.

  14. Beam-beam-induced orbit effects at LHC

    International Nuclear Information System (INIS)

    Schaumann, M; Fernandez, R Alemany

    2014-01-01

    For high bunch intensities the long-range beam-beam interactions are strong enough to provoke effects on the orbit. As a consequence the closed orbit changes. The closed orbit of an unperturbed machine with respect to a machine where the beam-beam force becomes more and more important has been studied and the results are presented in this paper

  15. Beam induced transit time signals at SPEAR

    International Nuclear Information System (INIS)

    McConnell, R.A.

    1975-01-01

    Beam induced signals at frequencies related to inter-cavity transit times have been detected at SPEAR. Whether this effect enters significantly into beam instabilities has not yet been determined. Preliminary experiments suggest that under certain conditions at low energy (1.5 GeV) , when μ/sub s/, passes through one of the transit time resonances, some current is lost. Care must be taken, however, not to confuse this effect, if it exists, with synchrobetatron resonances and with an as yet unexplained vertical instability in SPEAR. At high energy (3.7 GeV), no effect has been shown to exist, though detectable signals are present. 2 refs., 2 tabs

  16. (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.

  17. Higher-order harmonics of limited diffraction Bessel beams

    Science.gov (United States)

    Ding; Lu

    2000-03-01

    We investigate theoretically the nonlinear propagation of the limited diffraction Bessel beam in nonlinear media, under the successive approximation of the KZK equation. The result shows that the nth-order harmonic of the Bessel beam, like its fundamental component, is radially limited diffracting, and that the main beamwidth of the nth-order harmonic is exactly 1/n times that of the fundamental.

  18. Time resolved ion beam induced charge collection

    International Nuclear Information System (INIS)

    Sexton W, Frederick; Walsh S, David; Doyle L, Barney; Dodd E, Paul

    2000-01-01

    Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a -.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients

  19. Time resolved ion beam induced charge collection

    Energy Technology Data Exchange (ETDEWEB)

    SEXTON,FREDERICK W.; WALSH,DAVID S.; DOYLE,BARNEY L.; DODD,PAUL E.

    2000-04-01

    Under this effort, a new method for studying the single event upset (SEU) in microelectronics has been developed and demonstrated. Called TRIBICC, for Time Resolved Ion Beam Induced Charge Collection, this technique measures the transient charge-collection waveform from a single heavy-ion strike with a {minus}.03db bandwidth of 5 GHz. Bandwidth can be expanded up to 15 GHz (with 5 ps sampling windows) by using an FFT-based off-line waveform renormalization technique developed at Sandia. The theoretical time resolution of the digitized waveform is 24 ps with data re-normalization and 70 ps without re-normalization. To preserve the high bandwidth from IC to the digitizing oscilloscope, individual test structures are assembled in custom high-frequency fixtures. A leading-edge digitized waveform is stored with the corresponding ion beam position at each point in a two-dimensional raster scan. The resulting data cube contains a spatial charge distribution map of up to 4,096 traces of charge (Q) collected as a function of time. These two dimensional traces of Q(t) can cover a period as short as 5 ns with up to 1,024 points per trace. This tool overcomes limitations observed in previous multi-shot techniques due to the displacement damage effects of multiple ion strikes that changed the signal of interest during its measurement. This system is the first demonstration of a single-ion transient measurement capability coupled with spatial mapping of fast transients.

  20. Electron beam induced conductivity in 'PET' and 'FEP'

    International Nuclear Information System (INIS)

    Walzade, S.J.; Jog, J.P.; Dake, S.B.; Bhoraskar, S.V.

    1983-01-01

    Electron Beam Induced Conductivity (EBIC), classified into EBIC (bulk) and EBIC (surface) have been measured in PET and FEP respectively. The peculiar oscillatory nature of the induced gain versus beam energy variations is explained in terms of the spatial distributions of the trapping centres near the surface of the polymers. (author)

  1. Higher-order-mode damper as beam-position monitors; Higher-Order-Mode Daempfer als Stahllagemonitore

    Energy Technology Data Exchange (ETDEWEB)

    Peschke, C.

    2006-03-15

    In the framework of this thesis a beam-position monitor was developed, which can only because of the signals from the HOM dampers of a linear-accelerator structure determine the beam position with high accuracy. For the unique determination of the beam position in the plane a procedure was developed, which uses the amplitudes and the start-phase difference between a dipole mode and a higher monopole mode. In order tocheck the suitability of the present SBLC-HOM damper as beam position monitor three-dimensional numerical field calculations in the frequency and time range and measurements on the damper cell were performed. For the measurements without beam a beam simulator was constructed, which allows computer-driven measurements with variable depositions of the simulated beam with a resolution of 1.23 {mu}m. Because the complete 6 m long, 180-cell accelerator structure was not available for measurements and could also with the available computers not be three-dimensionally simulated simulated, a one-dimensional equivalent-circuit based model of the multi-cell was studied. The equivalent circuits with 879 concentrated components regards the detuning from cell to cell, the cell losses, the damper losses, and the beam excitation in dependence on the deposition. the measurements and simulations let a resolution of the ready beam-position monitor on the 180-cell in the order of magnitude of 1-10 {mu}m and a relative accuracy smaller 6.2% be expected.

  2. Ion beam induces nitridation of silicon

    International Nuclear Information System (INIS)

    Petravic, M.; Williams, J.S.; Conway, M.

    1998-01-01

    High dose ion bombardment of silicon with reactive species, such as oxygen and nitrogen, has attracted considerable interest due to possible applications of beam-induced chemical compounds with silicon. For example, high energy oxygen bombardment of Si is now routinely used to form buried oxide layers for device purposes, the so called SIMOX structures. On the other hand, Si nitrides, formed by low energy ( 100 keV) nitrogen beam bombardment of Si, are attractive as oxidation barriers or gate insulators, primarily due to the low diffusivity of many species in Si nitrides. However, little data exists on silicon nitride formation during bombardment and its angle dependence, in particular for N 2 + bombardment in the 10 keV range, which is of interest for analytical techniques such as SIMS. In SIMS, low energy oxygen ions are more commonly used as bombarding species, as oxygen provides stable ion yields and enhances the positive secondary ion yield. Therefore, a large body of data can be found in the literature on oxide formation during low energy oxygen bombardment. Nitrogen bombardment of Si may cause similar effects to oxygen bombardment, as nitrogen and oxygen have similar masses and ranges in Si, show similar sputtering effects and both have the ability to form chemical compounds with Si. In this work we explore this possibility in some detail. We compare oxide and nitride formation during oxygen and nitrogen ion bombardment of Si under similar conditions. Despite the expected similar behaviour, some large differences in compound formation were found. These differences are explained in terms of different atomic diffusivities in oxides and nitrides, film structural differences and thermodynamic properties. (author)

  3. Stress-tolerant mutants induced by heavy-ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Abe, Tomoko; Yoshida, Shigeo [Institute of Physical and Chemical Research, Wako, Saitama (Japan); Bae, Chang-Hyu [Sunchon National University, Sunchon (Korea); Ozaki, Takuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Wang, Jing Ming [Akita Prefectural Univ. (Japan)

    2000-07-01

    Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M{sub 1} seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M{sub 3} progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to {sup 14}N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M{sub 1} progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M{sub 1} seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

  4. Stress-tolerant mutants induced by heavy-ion beams

    International Nuclear Information System (INIS)

    Abe, Tomoko; Yoshida, Shigeo; Bae, Chang-Hyu; Ozaki, Takuo

    2000-01-01

    Comparative study was made on mutagenesis in tobacco embryo induced by exposure to EMS (ethyl methane-sulfonate) ion beams during the fertilization cycle. Tobacco embryo cells immediately after pollination were exposed to heavy ion beam and the sensitivity to the irradiation was assessed in each developmental stage and compared with the effects of EMS, a chemical mutagen. Morphologically abnormality such as chlorophyll deficiency was used as a marker. A total of 17 salt-tolerant plants were selected from 3447 M 1 seeds. A cell line showed salt resistance. The cell growth and chlorophyll content were each two times higher than that of WT cells in the medium containing 154 mM NaCl. Seven strains of M 3 progeny of 17 salt-tolerant plants, showed strong resistance, but no salt tolerant progeny were obtained from Xanthi or Ne-ion irradiation. This shows that the sensitivity of plant embryo to this irradiation technique may vary among species. When exposed to 14 N ion beam for 24-108 hours after pollination, various morphological mutants appeared at 18% in M 1 progeny and herbicide tolerant and salt tolerant mutants were obtained. A strong Co-tolerant strain was obtained in two of 17 salt-tolerant strains and a total of 46 tolerant strains (0.2%) were obtained from 22,272 grains of M 1 seeds. In these tolerant strains, the absorption of Co was slightly decreased, but those of Mg and Mn were increased. Mutants induced with ion-beam irradiation have potential not only for practical use in the breeding of stress-tolerant plants but also for gene analysis that will surely facilitate the molecular understanding of the tolerance mechanisms. (M.N.)

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

    Science.gov (United States)

    Ahmad, S. B.; McNeill, F. E.; Byun, S. H.; Prestwich, W. V.; Seymour, C.; Mothersill, C. E.

    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 × 1013 H+/cm2 s. The average saturation value for the photon output was found to be 40 × 106 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 × 103, 10 × 106, and 35 × 106 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 10-14 cm2. 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.

  6. Scrape-off layer-induced beam density fluctuations and their effect on beam emission spectroscopy

    Science.gov (United States)

    Moulton, D.; Marandet, Y.; Tamain, P.; Dif-Pradalier, G.

    2015-07-01

    A statistical model is presented to calculate the magnitude of beam density fluctuations generated by a turbulent scrape-off layer (SOL). It is shown that the SOL can induce neutral beam density fluctuations of a similar magnitude to the plasma density fluctuations in the core, potentially corrupting beam emission spectroscopy measurements. The degree of corruption is quantified by combining simulations of beam and plasma density fluctuations inside a simulated measurement window. A change in pitch angle from the separatrix to the measurement window is found to reduce the effect of beam fluctuations, whose largest effect is to significantly reduce the measured correlation time.

  7. Investigations on ion-beam induced desorption from cryogenic surfaces

    International Nuclear Information System (INIS)

    Maurer, Christoph

    2017-01-01

    A central component of FAIR, the Facility for Antiproton and Ion Research, will be the superconducting heavy ion synchrotron SIS100, which is supposed to provide reliable, high intensity beams for various applications. Its beam intensity is governed by the space charge limit, while the maximum energy is determined by the machine's magnetic rigidity. That means, ions with higher charge state can be accelerated to a higher energy, but with less intensity. For highest intensity beams, intermediate charge states have to be used instead of high charge state ions. This alleviates the issue of space charge but gives rise to dynamic vacuum effects, which also limit beam intensity: beam particles collide with residual gas particles, which leads to charge exchange and their subsequent loss. Impacting on the chamber wall, these ions release adsorbed gas particles. This process is called desorption and leads to a localized increase in pressure, which in turn causes more charge exchange. After a few rounds of self amplification, this can lead to total beam loss. This ''runaway-desorption'' is typically the main beam intensity limiting process for intermediate charge state (heavy) ion beams. The extent of this phenomenon is governed by two factors: the initial beam intensity and the desorption yield. The latter is examined within the scope of this thesis. Special emphasis is placed on the influence of the target's temperature, since the SIS100 will be a superconducting machine with cryogenic vacuum chamber walls. In order to investigate this topic, an experimental setup has been devised, built at the SIS18 and taken into commission. Based on the experience gained during operation, it has been continuously improved and extended. Another central innovation presented in this thesis is the use of gas dynamics simulations for an improved method of data analysis. Using this technique, environmental conditions like the chamber geometry and the connected

  8. Electron beam induced modification of grafted polyamides

    International Nuclear Information System (INIS)

    Timus, D.M.; Brasoveanu, M.M.; Bradley, D.A.; Popov, A.M.

    1998-01-01

    It is well known that irradiation, when applied on its own or in combination with other physical and chemical treatments, can manifest in radiation damage to materials. Radiation processing technology focuses upon producing favourable modification of materials through use of relatively high dose and dose rates. Current interest is in modifying the thermal and electrical properties of textured polymers in an effort to improve safety and wear comfort of clothing. No less important is the production of textiles which are safe to use, both in homes and offices. Present investigations provide additional data in support of findings which show that polyamides, a particular class of textured polymer, are amenable to radiation processing. Accelerated electron beam irradiation of sheets of polyamide fibre results in induced grafting of acrylic and methacrylic acids. The degree of grafting is critically dependent upon irradiation dose and the extent of monomers dilution. Of particular importance is the high correlation which is found between degree of grafting and a decrease in the softening rate of the modified polyamide. A systematic modification of electrical conductivity is also observed. (author)

  9. Higher-order Bessel like beams with z-dependent cone angles

    CSIR Research Space (South Africa)

    Ismail, Y

    2010-08-01

    Full Text Available .64.81.22. Terms of Use: http://spiedl.org/terms Fig.5: Optical design to generate z-dependent Bessel-like beams 4. CONSIDERING A MATHEMATICAL APPROACH TO EXPLAINING Z-DEPENDENT BLB?S The stationary phase method is implemented in order to confirm... on higher-order z-dependent BLB?s [6]. 5. EXPERIMENTALLY GENERATED Z-DEPENDENT BESSEL-LIKE BEAMS From the above in can be deduced that these beams are Bessel-like hence they are so named z-dependent Bessel-like beams. These beams are produced however...

  10. Focused ion beam induced deflections of freestanding thin films

    International Nuclear Information System (INIS)

    Kim, Y.-R.; Chen, P.; Aziz, M. J.; Branton, D.; Vlassak, J. J.

    2006-01-01

    Prominent deflections are shown to occur in freestanding silicon nitride thin membranes when exposed to a 50 keV gallium focused ion beam for ion doses between 10 14 and 10 17 ions/cm 2 . Atomic force microscope topographs were used to quantify elevations on the irradiated side and corresponding depressions of comparable magnitude on the back side, thus indicating that what at first appeared to be protrusions are actually the result of membrane deflections. The shape in high-stress silicon nitride is remarkably flat-topped and differs from that in low-stress silicon nitride. Ion beam induced biaxial compressive stress generation, which is a known deformation mechanism for other amorphous materials at higher ion energies, is hypothesized to be the origin of the deflection. A continuum mechanical model based on this assumption convincingly reproduces the profiles for both low-stress and high-stress membranes and provides a family of unusual shapes that can be created by deflection of freestanding thin films under beam irradiation

  11. 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

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

    Directory of Open Access Journals (Sweden)

    B. Auchmann

    2015-06-01

    Full Text Available 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.

  13. 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.

  14. 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.

  15. Resistance and sheet resistance measurements using electron beam induced current

    International Nuclear Information System (INIS)

    Czerwinski, A.; Pluska, M.; Ratajczak, J.; Szerling, A.; KaPtcki, J.

    2006-01-01

    A method for measurement of spatially uniform or nonuniform resistance in layers and strips, based on electron beam induced current (EBIC) technique, is described. High electron beam currents are used so that the overall resistance of the measurement circuit affects the EBIC signal. During the evaluation, the electron beam is scanned along the measured object, whose load resistance varies with the distance. The variation is compensated by an adjustable resistance within an external circuit. The method has been experimentally deployed for sheet resistance determination of buried regions of lateral confinements in semiconductor laser heterostructures manufactured by molecular beam epitaxy

  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. 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.

  18. Proton beam induced dynamics of tungsten granules

    Science.gov (United States)

    Caretta, O.; Loveridge, P.; O'Dell, J.; Davenne, T.; Fitton, M.; Atherton, A.; Densham, C.; Charitonidis, N.; Efthymiopoulos, I.; Fabich, A.; Guinchard, M.; Lacny, L. J.; Lindstrom, B.

    2018-03-01

    This paper reports the results from single-pulse experiments of a 440 GeV /c proton beam interacting with granular tungsten samples in both vacuum and helium environments. Remote high-speed photography and laser Doppler vibrometry were used to observe the effect of the beam on the sample grains. The majority of the results were derived from a trough containing ˜45 μ m diameter spheres (not compacted) reset between experiments to maintain the same initial conditions. Experiments were also carried out on other open and contained samples for the purposes of comparison both with the 45 μ m grain results and with a previous experiment carried out with sub-250 μ m mixed crystalline tungsten powder in helium [Phys. Rev. ST Accel. Beams 17, 101005 (2014), 10.1103/PhysRevSTAB.17.101005]. The experiments demonstrate that a greater dynamic response is produced in a vacuum than in a helium environment and in smaller grains compared with larger grains. The examination of the dynamics of the grains after a beam impact leads to the hypothesis that the grain response is primarily the result of a charge interaction of the proton beam with the granular medium.

  19. Proton beam induced dynamics of tungsten granules

    Directory of Open Access Journals (Sweden)

    O. Caretta

    2018-03-01

    Full Text Available This paper reports the results from single-pulse experiments of a 440  GeV/c proton beam interacting with granular tungsten samples in both vacuum and helium environments. Remote high-speed photography and laser Doppler vibrometry were used to observe the effect of the beam on the sample grains. The majority of the results were derived from a trough containing ∼45  μm diameter spheres (not compacted reset between experiments to maintain the same initial conditions. Experiments were also carried out on other open and contained samples for the purposes of comparison both with the 45  μm grain results and with a previous experiment carried out with sub-250  μm mixed crystalline tungsten powder in helium [Phys. Rev. ST Accel. Beams 17, 101005 (2014PRABFM1098-440210.1103/PhysRevSTAB.17.101005]. The experiments demonstrate that a greater dynamic response is produced in a vacuum than in a helium environment and in smaller grains compared with larger grains. The examination of the dynamics of the grains after a beam impact leads to the hypothesis that the grain response is primarily the result of a charge interaction of the proton beam with the granular medium.

  20. Higher Order Modes Excitation of Micro Cantilever Beams

    KAUST Repository

    Jaber, Nizar

    2014-05-01

    In this study, we present analytical and experimental investigation of electrically actuated micro cantilever based resonators. These devices are fabricated using polyimide and coated with chrome and gold layers from both sides. The cantilevers are highly curled up due to stress gradient, which is a common imperfection in surface micro machining. Using a laser Doppler vibrometer, we applied a noise signal to experimentally find the first four resonance frequencies. Then, using a data acquisition card, we swept the excitation frequency around the first four natural modes of vibrations. Theoretically, we derived a reduced order model using the Galerkin method to simulate the dynamics of the system. Extensive numerical analysis and computations were performed. The numerical analysis was able to provide good matching with experimental values of the resonance frequencies. Also, we proved the ability to excite higher order modes using partial electrodes with shapes that resemble the shape of the mode of interest. Such micro-resonators are shown to be promising for applications in mass and gas sensing.

  1. 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.

  2. Influence of laser beam profile on electromagnetically induced absorption

    International Nuclear Information System (INIS)

    Cuk, S. M.; Radonjic, M.; Krmpot, A. J.; Nikolic, S. N.; Grujic, Z. D.; Jelenkovic, B. M.

    2010-01-01

    We compared, experimentally and theoretically, Hanle electromagnetically induced absorption (EIA) obtained using Gaussian and Π-shaped laser beams 3 mm in diameter. The study was done by measuring the transmission of a laser locked to the F g =2→F e =3 transition at the D 2 line of 87 Rb in a vacuum cell. EIA linewidths obtained for the two laser profiles were significantly different in the range of laser intensities 1-4 mW/cm 2 . EIA with the Π-shaped laser beam has a broad intensity maximum and linewidths larger than those obtained with the Gaussian beam profile. We also studied Hanle EIA by measuring the transmission of selected segments of the entire laser beam by placing a small movable aperture in front of the detector. Waveforms so obtained in Hanle EIA resonances were strongly influenced both by the radial distance of the transmitted segment from the beam center and by the radial profile of the laser beam. We show that outer regions of Gaussian beam, and central regions of the Π-shaped beam generate the narrowest lines. The different behaviors of EIA owing to different beam profiles revealed by both theory and experiment indicate the importance of the radial profile of the laser beam for proper modeling of coherent effects in alkali metal vapors.

  3. Graphene defects induced by ion beam

    Science.gov (United States)

    Gawlik, Grzegorz; Ciepielewski, Paweł; Baranowski, Jacek; Jagielski, Jacek

    2017-10-01

    The CVD graphene deposited on the glass substrate was bombarded by molecular carbon ions C3+ C6+ hydrocarbon ions C3H4+ and atomic ions He+, C+, N+, Ar+, Kr+ Yb+. Size and density of ion induced defects were estimated from evolution of relative intensities of Raman lines D (∼1350 1/cm), G (∼1600 1/cm), and D‧ (∼1620 1/cm) with ion fluence. The efficiency of defect generation by atomic ions depend on ion mass and energy similarly as vacancy generation directly by ion predicted by SRIM simulations. However, efficiency of defect generation in graphene by molecular carbon ions is essentially higher than summarized efficiency of similar group of separate atomic carbon ions of the same energy that each carbon ion in a cluster. The evolution of the D/D‧ ratio of Raman lines intensities with ion fluence was observed. This effect may indicate evolution of defect nature from sp3-like at low fluence to a vacancy-like at high fluence. Observed ion graphene interactions suggest that the molecular ion interacts with graphene as single integrated object and should not be considered as a group of atomic ions with partial energy.

  4. 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.

    2015-06-25

    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...

  5. Electron beam induced emission from carbon plasmas

    International Nuclear Information System (INIS)

    Whetstone, S.; Kammash, T.

    1989-01-01

    Plasma use as a lasing medium has many potential advantages over conventional techniques including increased power levels and greater wavelength ranges. The basic concept is to heat and then rapidly cool a plasma forcing inversion through bottleneck creation between the recombination reaction populating a given energy level and the subsequent decay processes. Much effort has been devoted to plasmas heated by lasers and pinch devices. The authors are concerned here with electron beam heated plasmas focusing on the CIV 5g-4f transition occurring at 2530 Angstroms. These studies were initiated to provide theoretical support for experiments being performed at the University of Michigan using the Michigan Electron Long-Pulse Beam Accelerator (MELBA)

  6. Stability study of the higher order mode beam position monitors at the Accelerating cavities at FLASH

    CERN Document Server

    Shi, L; Jones., R M

    2014-01-01

    erating cavities at FLASH linac, DESY, are equipped with electronics for beam position monitoring, which are based on HOM signals from special couplers. These monitors provide the beam position without additional vacuum components and at low cost. Moreover, they can be used to align the beam in the cavities to reduce the HOM effects on the beam. However, the HOMBPM (Higher Order Mode based Beam Position Monitor) shows an instability problem over time. In this paper, we will present the status of studies on this issue. Several methods are utilized to calibrate the HOMBPMs. These methods include DLR (Direct Linear Regression), and SVD (Singular Value Decomposition). We found that SVD generally is more suitable for HOMBPM calibration. We focus on the HOMBPMs at 1.3 GHz cavities. Techniques developed here are applicable to 3.9 ...

  7. Silicon radiation detector analysis using back electron beam induced current

    International Nuclear Information System (INIS)

    Guye, R.

    1987-01-01

    A new technique for the observation and analysis of defects in silicon radiation detectors is described. This method uses an electron beam from a scanning electron microscope (SEM) impinging on the rear side of the p + n junction of the silicon detector, which itself is active and detects the electron beam induced current (EBIC). It is shown that this current is a sensitive probe of localized trapping centers, either at the junction surface or somewhere in the volume of the silicon crystal. (orig.)

  8. Effect of beam density and of higher harmonics on beam-plasma interaction

    International Nuclear Information System (INIS)

    Lacina, J.; Krlin, L.; Koerbel, S.

    1974-10-01

    The interaction in a cold electron beam-plasma system is investigated numerically in a density ratio region of nsub(B)/nsub(P) = 2 x 10 -3 to 2 x 10 -2 . The one-dimensional model of a collisionless plasma is used. The time development of the wave with maximal growing rate and its spatial harmonics is studied. The plasma effect is simulated by direct computation of plasma particle trajectories (this being different from the usual plasma simulation by means of a dielectric). The calculations show the following effects of the finite parameter (nsub(B)/nsub(P))sup(1/3): the ratio of the plasma energy to the electric field energy is increased, the damping character of the field and macroscopic amplitudes reveals, and the influence of the second harmonic is not negligible for nsub(B)/nsub(P) >= 10 -2 . (author)

  9. Propagation of high power electromagnetic beam in relativistic magnetoplasma: Higher order paraxial ray theory

    Science.gov (United States)

    Gill, Tarsem Singh; Kaur, Ravinder; Mahajan, Ranju

    2010-09-01

    This paper presents an analysis of self-consistent, steady-state, theoretical model, which explains the ring formation in a Gaussian electromagnetic beam propagating in a magnetoplasma, characterized by relativistic nonlinearity. Higher order terms (up to r4) in the expansion of the dielectric function and the eikonal have been taken into account. The condition for the formation of a dark and bright ring derived earlier by Misra and Mishra [J. Plasma Phys. 75, 769 (2009)] has been used to study focusing/defocusing of the beam. It is seen that inclusion of higher order terms does significantly affect the dependence of the beam width on the distance of propagation. Further, the effect of the magnetic field and the nature of nonlinearity on the ring formation and self-focusing of the beam have been explored.

  10. Propagation of high power electromagnetic beam in relativistic magnetoplasma: Higher order paraxial ray theory

    International Nuclear Information System (INIS)

    Gill, Tarsem Singh; Kaur, Ravinder; Mahajan, Ranju

    2010-01-01

    This paper presents an analysis of self-consistent, steady-state, theoretical model, which explains the ring formation in a Gaussian electromagnetic beam propagating in a magnetoplasma, characterized by relativistic nonlinearity. Higher order terms (up to r 4 ) in the expansion of the dielectric function and the eikonal have been taken into account. The condition for the formation of a dark and bright ring derived earlier by Misra and Mishra [J. Plasma Phys. 75, 769 (2009)] has been used to study focusing/defocusing of the beam. It is seen that inclusion of higher order terms does significantly affect the dependence of the beam width on the distance of propagation. Further, the effect of the magnetic field and the nature of nonlinearity on the ring formation and self-focusing of the beam have been explored.

  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.

    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....

  12. 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...

  13. Electron-beam induced conduction in some polymers

    International Nuclear Information System (INIS)

    Suzuoki, Yasuo; Mizutani, Teruyoshi; Ieda, Masayuki

    1976-01-01

    The charge signal induced by pulsed electron beam consists of two components, i.e. the fast and the slow components. The slow component which corresponds to carrier transport via shallow traps exhibited an asymmetry with respect to the bias field polarity. The asymmetry revealed that the main carriers which drifted via shallow traps were electrons in PET, both electrons and holes in PEN, and holes in PS. TSC spectra of electron-beam induced electrets proved directly the existence of electron shallow traps in PET and both electron and hole traps in PEN. Their trap energies were 0.1 to 0.2 eV. (auth.)

  14. Analysis of warping deformation modes using higher order ANCF beam element

    Science.gov (United States)

    Orzechowski, Grzegorz; Shabana, Ahmed A.

    2016-02-01

    Most classical beam theories assume that the beam cross section remains a rigid surface under an arbitrary loading condition. However, in the absolute nodal coordinate formulation (ANCF) continuum-based beams, this assumption can be relaxed allowing for capturing deformation modes that couple the cross-section deformation and beam bending, torsion, and/or elongation. The deformation modes captured by ANCF finite elements depend on the interpolating polynomials used. The most widely used spatial ANCF beam element employs linear approximation in the transverse direction, thereby restricting the cross section deformation and leading to locking problems. The objective of this investigation is to examine the behavior of a higher order ANCF beam element that includes quadratic interpolation in the transverse directions. This higher order element allows capturing warping and non-uniform stretching distribution. Furthermore, this higher order element allows for increasing the degree of continuity at the element interface. It is shown in this paper that the higher order ANCF beam element can be used effectively to capture warping and eliminate Poisson locking that characterizes lower order ANCF finite elements. It is also shown that increasing the degree of continuity requires a special attention in order to have acceptable results. Because higher order elements can be more computationally expensive than the lower order elements, the use of reduced integration for evaluating the stress forces and the use of explicit and implicit numerical integrations to solve the nonlinear dynamic equations of motion are investigated in this paper. It is shown that the use of some of these integration methods can be very effective in reducing the CPU time without adversely affecting the solution accuracy.

  15. RELAXATION OF BLAZAR-INDUCED PAIR BEAMS IN COSMIC VOIDS

    Energy Technology Data Exchange (ETDEWEB)

    Miniati, Francesco [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Elyiv, Andrii, E-mail: fm@phys.ethz.ch [Institut d' Astrophysique et de Geophysique, Universite de Liege, B-4000 Liege (Belgium)

    2013-06-10

    The stability properties of a low-density ultrarelativistic pair beam produced in the intergalactic medium (IGM) by multi-TeV gamma-ray photons from blazars are analyzed. The problem is relevant for probes of magnetic field in cosmic voids through gamma-ray observations. In addition, dissipation of such beams could considerably affect the thermal history of the IGM and structure formation. We use a Monte Carlo method to quantify the properties of the blazar-induced electromagnetic shower, in particular the bulk Lorentz factor and the angular spread of the pair beam generated by the shower, as a function of distance from the blazar itself. We then use linear and nonlinear kinetic theory to study the stability of the pair beam against the growth of electrostatic plasma waves, employing the Monte Carlo results for our quantitative estimates. We find that the fastest growing mode, like any perturbation mode with even a very modest component perpendicular to the beam direction, cannot be described in the reactive regime. Due to the effect of nonlinear Landau damping, which suppresses the growth of plasma oscillations, the beam relaxation timescale is found to be significantly longer than the inverse Compton loss time. Finally, density inhomogeneities associated with cosmic structure induce loss of resonance between the beam particles and plasma oscillations, strongly inhibiting their growth. We conclude that relativistic pair beams produced by blazars in the IGM are stable on timescales that are long compared with the electromagnetic cascades. There appears to be little or no effect of pair beams on the IGM.

  16. Compositional changes in industrial hemp biomass (Cannabis sativa L.) induced by electron beam irradiation Pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Yong Joo [Department of Biobased Materials, College of Agriculture and Life Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Shin, Soo-Jeong [Department of Wood and Paper Science, College of Agriculture and Life Science, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2011-07-15

    The effects of electron beam irradiation on chemical decomposition of industrial hemp biomass were evaluated at doses of 150, 300, and 450 kGy. The quantity of decomposed components was indirectly estimated by measuring changes in alkaline extraction. The more severe degradation of structural components induced by higher irradiation doses resulted in larger amounts of alkaline extract. Carbohydrate compositional analysis using {sup 1}H-NMR spectroscopy was applied to quantitatively investigate changes in the polysaccharides of the industrial hemp. The xylose peak intensity in the NMR spectra decreased with increasing electron irradiation dose, indicating that xylan was more sensitive to electron beam irradiation than cellulose. -- Highlights: {yields} The more severe degradation of structural components induced by higher irradiation. {yields} Carbohydrate analysis was applied to quantitatively investigate changes in the industrial hemp. {yields} Xylan was more sensitive to electron beam irradiation than cellulose.

  17. Compositional changes in industrial hemp biomass (Cannabis sativa L.) induced by electron beam irradiation Pretreatment

    International Nuclear Information System (INIS)

    Sung, Yong Joo; Shin, Soo-Jeong

    2011-01-01

    The effects of electron beam irradiation on chemical decomposition of industrial hemp biomass were evaluated at doses of 150, 300, and 450 kGy. The quantity of decomposed components was indirectly estimated by measuring changes in alkaline extraction. The more severe degradation of structural components induced by higher irradiation doses resulted in larger amounts of alkaline extract. Carbohydrate compositional analysis using 1 H-NMR spectroscopy was applied to quantitatively investigate changes in the polysaccharides of the industrial hemp. The xylose peak intensity in the NMR spectra decreased with increasing electron irradiation dose, indicating that xylan was more sensitive to electron beam irradiation than cellulose. -- Highlights: → The more severe degradation of structural components induced by higher irradiation. → Carbohydrate analysis was applied to quantitatively investigate changes in the industrial hemp. → Xylan was more sensitive to electron beam irradiation than cellulose.

  18. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    CERN Document Server

    Zhang, P; Baboi, Nicoleta

    2012-01-01

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrum...

  19. Analysis of the beam induced heat loads on the LHC arc beam screens during Run 2

    CERN Document Server

    Iadarola, Giovanni; Dijkstal, Philipp; Mether, Lotta; CERN. Geneva. ATS Department

    2017-01-01

    During Run 2 the Large Hadron Collider (LHC) has been routinely operated with 25 ns bunch spacing. In these conditions large heat loads have been measured on the beam screens of the superconducting magnets, together with other observations indicating that an electron cloud develops in the beam chambers. The analysis of these heat loads has revealed several interesting features allowing to pinpoint peculiar characteristics of the observed beam-induced heating. This document describes the main findings of this analysis including the evolution taking place during the run, the observed dependence on the beam conditions and the results from special tests and dedicated instrumentation. The differences observed in the behavior of the eight LHC arcs are also discussed.

  20. Controlled generation of higher-order Poincaré sphere beams from a laser

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2016-03-01

    Full Text Available . 10: 327-332 Controlled generation of higher-order Poincaré sphere beams from a laser Naidoo D Roux FS Dudley A Litvin I Piccirillo B Marrucci L Forbes A ABSTRACT: The angular momentum of light can be described by positions on a...

  1. Superpositions of higher-order bessel beams and nondiffracting speckle fields

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-08-01

    Full Text Available speckle fields. The paper reports on illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two higher-order Bessel beams. In the case that the phase dependence of the light...

  2. Shape invariant higher-order Bessel-like beams carrying orbital angular momentum

    CSIR Research Space (South Africa)

    Ismail, Y

    2012-09-01

    Full Text Available -1 Journal of Optics September 2012/ Vol. 14 Shape invariant higher-order Bessel-like beams carrying orbital angular momentum Y Ismail1,2, N Khilo3, V Belyi3 and A Forbes1,2 1 School of Physics, University of KwaZulu-Natal, Private Bag X54001...

  3. Superpositions of higher-order bessel beams and nondiffracting speckle fields - (SAIP 2009)

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-07-01

    Full Text Available speckle fields. The paper reports on illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two higher-order Bessel beams. In the case that the phase dependence of the light...

  4. Observations and control of beam instabilities due to higher order modes in Indus-2

    International Nuclear Information System (INIS)

    Arora, Rajiv K.; Prasad, M.; Lad, M.; Hannurkar, P.R.

    2013-01-01

    In a synchrotron radiation source (SRS), the interaction between electron beam spectra and Higher Order Modes (HOMs) of RF cavities may give rise to coupled bunch instabilities. These instabilities may limit beam current and beam lifetime. Indus-2 SRS has four RF cavities equipped with precision temperature controller of cooling system and Higher Order Mode Frequency Shifter (HOMFS) to avoid harmful HOMs. Offline (i.e. without beam) and Online (i.e. with beam) measurements, observations and analysis of HOMs have been performed. Some of the Longitudinal modes such as L1 (∼ 950 MHz), L3 (∼ 1432 MHz), L4 (∼ 1521 MHz), L5 (∼1628 MHz) were observed to be quite prominent at specific operating conditions. Based on these studies, harmful HOMs were identified and suitable methods were evolved to avoid these HOMs. Experiments were performed to achieve high beam current in Indus-2. The precision chiller temperatures and HOMFS positions were set as per theoretical estimates and were further optimized in fine steps during experiments. With the optimized settings, beam current around 200 mA at Injection energy (550 MeV) and 157 mA at 2.5 GeV has been successfully achieved. At these settings of RF cavity water temperature and HOMFS, harmful HOMs were within safe limits during regular operation of Indus-2 at 2.5 GeV/100 mA in user mode for more than one year. In this paper, important observations, analysis and experiments to avoid harmful HOMs of RF cavities are presented. (author)

  5. Electron Beam Induced Functionalization of Fluoropolymers

    International Nuclear Information System (INIS)

    Lappan, U.

    2006-01-01

    Ionizing radiation affects the properties of polymers by chain scission and cross-linking reactions. One process will usually predominate, depending on the chemical structure of the polymer and the irradiation conditions such as temperature and atmosphere. Poly(tetrafluoroethylene) (PTFE) and the perfluorinated copolymers poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) (PFA) undergo predominantly chain scission, if the irradiation is performed at room temperature. This shortcoming is exploited by converting PTFE into low molecular weight micropowders. The irradiation of PTFE in the presence of air results in micropowders functionalized with oxygen-containing groups. The concentration of end groups was investigated by FTIR and 19F solid-state NMR. The data were used to calculate number-average molecular weights. It was demonstrated that PTFE can be cross-linked by irradiation above its crystalline melting temperature in an oxygen-free atmosphere. Evidence for cross-links in PTFE was derived directly from structural information using 19 F solid-state NMR. FEP is understood to undergo cross-linking by irradiation above the glass transition temperature. It was found that also PFA can be branched and cross-linked by irradiation under special conditions. Radiation-induced grafting of styrene into fluoropolymer films and subsequent sulfonation offers an attractive way to prepare proton exchange membranes. Recently, radiation-induced grafting into cross-linked PTFE was reported. Modified FEP, PFA and ETFE films have been used as base material in this study. The modified films have been prepared by irradiation in nitrogen atmosphere at different temperatures up to temperatures above the melting temperature of the fluoropolymer

  6. The future of focused electron beam-induced processing

    International Nuclear Information System (INIS)

    Hagen, C.W.

    2014-01-01

    A perspective is sketched for the field of focused electron beam-induced processing (FEBIP). The FEBIP lithography technique is compared to the very successful resist-based electron beam lithography (EBL) technique. The advantages of FEBIP over EBL are identified, the main advantage being its high spatial resolution. This will enable FEBIP to become an important lithography technique for the fabrication of devices with critical dimension in the range between 1 and 20 nm and serve as a complementary technique to EBL. It will be discussed what needs to be done to achieve this and what the potential applications are. (orig.)

  7. Transverse vibrations of shear-deformable beams using a general higher order theory

    Science.gov (United States)

    Kosmatka, J. B.

    1993-01-01

    A general higher order theory is developed to study the static and vibrational behavior of beam structures having an arbitrary cross section that utilizes both out-of-plane shear-dependent warping and in-plane (anticlastic) deformations. The equations of motion are derived via Hamilton's principle, where the full 3D constitutive relations are used. A simplified version of the general higher-order theory is also presented for beams having an arbitrary cross section that includes out-of-plane shear deformation but assumes that stresses within the cross section and in-plane deformations are negligible. This simplified model, which is accurate for long to moderately short wavelengths, offers substantial improvements over existing higher order theories that are limited to beams with thin rectangular cross sections. The current approach will be very useful in the study of thin-wall closed-cell beams such as airfoil-type sections where the magnitude of shear-related cross-sectional warping is significant.

  8. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    International Nuclear Information System (INIS)

    Zhang, Pei

    2013-02-01

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  9. Beam position diagnostics with higher order modes in third harmonic superconducting accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei

    2013-02-15

    Higher order modes (HOM) are electromagnetic resonant fields. They can be excited by an electron beam entering an accelerating cavity, and constitute a component of the wakefield. This wakefield has the potential to dilute the beam quality and, in the worst case, result in a beam-break-up instability. It is therefore important to ensure that these fields are well suppressed by extracting energy through special couplers. In addition, the effect of the transverse wakefield can be reduced by aligning the beam on the cavity axis. This is due to their strength depending on the transverse offset of the excitation beam. For suitably small offsets the dominant components of the transverse wakefield are dipole modes, with a linear dependence on the transverse offset of the excitation bunch. This fact enables the transverse beam position inside the cavity to be determined by measuring the dipole modes extracted from the couplers, similar to a cavity beam position monitor (BPM), but requires no additional vacuum instrumentation. At the FLASH facility in DESY, 1.3 GHz (known as TESLA) and 3.9 GHz (third harmonic) cavities are installed. Wakefields in 3.9 GHz cavities are significantly larger than in the 1.3 GHz cavities. It is therefore important to mitigate the adverse effects of HOMs to the beam by aligning the beam on the electric axis of the cavities. This alignment requires an accurate beam position diagnostics inside the 3.9 GHz cavities. It is this aspect that is focused on in this thesis. Although the principle of beam diagnostics with HOM has been demonstrated on 1.3 GHz cavities, the realization in 3.9 GHz cavities is considerably more challenging. This is due to the dense HOM spectrum and the relatively strong coupling of most HOMs amongst the four cavities in the third harmonic cryo-module. A comprehensive series of simulations and HOM spectra measurements have been performed in order to study the modal band structure of the 3.9 GHz cavities. The dependencies of

  10. Electron-beam-induced conduction in polyethylene terephthalate films

    Energy Technology Data Exchange (ETDEWEB)

    Beckley, L M; Lewis, T J; Taylor, D M [University Coll. of North Wales, Bangor (UK). School of Electronic Engineering Science

    1976-06-21

    Measurements are reported of electron-beam-induced conduction in thin polyethylene terephthalate (PET) films for electron energies up to 10 keV. The ratio of induced dielectric current to incident beam current (the gain) is orders of magnitude less than unity over practically the whole range of beam penetration. This result is quite unlike that normally found for inorganic dielectrics where the gain will exceed unity and reach a maximum at or near full penetration. In spite of the very different gain characteristics it is shown that the model recently proposed by Nunes de Oliviera and Gross (J. App. Phys.; 46:3132 (1975)), and by Aris et al (IEE Conf. Publ. No.129.; 267 (1975) and J. Phys. C. Solid State Phys.; 9:797 (1976)) and applied to mica and tantalum oxide respectively is also applicable to PET. Use is made of the known carrier mobility and lifetime data for this polymer and it is shown that very large space-charge distortions of the field can be produced by the beam which may well account for the frequent sample failure experienced during the experiments. The work supports suggestions by earlier workers that the current in unirradiated PET is electrode limited and predicts the maximum (space-charge limited) current likely to occur in this polymer.

  11. 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...

  12. Initial operation of the LEDA beam-induced fluorescence diagnostic

    International Nuclear Information System (INIS)

    Kamperschroer, James H.; Gurd, Pamela A.; Martinez, Derwin G.; Gilpatrick, J. Douglas; Shurter, R. Bradford; Stettler, Matthew W.; Madsen, David W.; O'Hara, James F.; Sage, Joan; Schaefer, Timothy L.

    2000-01-01

    A diagnostic based on beam-induced fluorescence has been developed and used to examine the expanded beam in the High-Energy Beam Transport (HEBT) section of the Low Energy Demonstration Accelerator (LEDA). The system consists of a camera, a gas injector, a spectrometer, and a control system. Gas is injected to provide a medium for the beam to excite, the camera captures the resulting image of the fluorescing gas, and the spectrometer measures the spectrum of the emitted light. EPICS was used to control the camera and acquire and store images. Data analysis is presently being performed offline. A Kodak DCS420m professional CCD camera is the primary component of the optical system. InterScience, Inc. modified the camera with the addition of a gain of 4000 image intensifier, thereby producing an intensified camera with a sensitivity of ∼0.5 milli-lux. Light is gathered with a 1 '' format, 16-160 mm, Computar zoom lens. This lens is attached to the camera via a Century Precision Optics relay lens. Images obtained using only hydrogen from the beam stop exhibited features not yet understood. Images with good signal-to-noise ratio were obtained with the injection of sufficient nitrogen to raise the HEBT pressure to 2-8x10 -6 torr. Two strong nitrogen lines, believed to be of the first negative group of N 2 + , were identified at 391 and 428 nm

  13. Atomistic modeling of ion beam induced amorphization in silicon

    International Nuclear Information System (INIS)

    Pelaz, Lourdes; Marques, Luis A.; Lopez, Pedro; Santos, Ivan; Aboy, Maria; Barbolla, Juan

    2005-01-01

    Ion beam induced amorphization in Si has attracted significant interest since the beginning of the use of ion implantation for the fabrication of Si devices. Nowadays, a renewed interest in the modeling of amorphization mechanisms at atomic level has arisen due to the use of preamorphizing implants and high dopant implantation doses for the fabrication of nanometric-scale Si devices. In this work, we briefly describe the existing phenomenological and defect-based amorphization models. We focus on the atomistic model we have developed to describe ion beam induced amorphization in Si. In our model, the building block for the amorphous phase is the bond defect or IV pair, whose stability increases with the number of surrounding IV pairs. This feature explains the regrowth behavior of different damage topologies and the kinetics of the crystalline to amorphous transition. The model provides excellent quantitative agreement with experimental results

  14. A critical literature review of focused electron beam induced deposition

    International Nuclear Information System (INIS)

    Dorp, W. F. van; Hagen, C. W.

    2008-01-01

    An extensive review is given of the results from literature on electron beam induced deposition. Electron beam induced deposition is a complex process, where many and often mutually dependent factors are involved. The process has been studied by many over many years in many different experimental setups, so it is not surprising that there is a great variety of experimental results. To come to a better understanding of the process, it is important to see to which extent the experimental results are consistent with each other and with the existing model. All results from literature were categorized by sorting the data according to the specific parameter that was varied (current density, acceleration voltage, scan patterns, etc.). Each of these parameters can have an effect on the final deposit properties, such as the physical dimensions, the composition, the morphology, or the conductivity. For each parameter-property combination, the available data are discussed and (as far as possible) interpreted. By combining models for electron scattering in a solid, two different growth regimes, and electron beam induced heating, the majority of the experimental results were explained qualitatively. This indicates that the physical processes are well understood, although quantitatively speaking the models can still be improved. The review makes clear that several major issues remain. One issue encountered when interpreting results from literature is the lack of data. Often, important parameters (such as the local precursor pressure) are not reported, which can complicate interpretation of the results. Another issue is the fact that the cross section for electron induced dissociation is unknown. In a number of cases, a correlation between the vertical growth rate and the secondary electron yield was found, which suggests that the secondary electrons dominate the dissociation rather than the primary electrons. Conclusive evidence for this hypothesis has not been found. Finally

  15. Laser induced focusing for over-dense plasma beams

    International Nuclear Information System (INIS)

    Schmidt, Peter; Boine-Frankenheim, Oliver; Mulser, Peter

    2015-01-01

    The capability of ion acceleration with high power, pulsed lasers has become an active field of research in the past years. In this context, the radiation pressure acceleration (RPA) mechanism has been the topic of numerous theoretical and experimental publications. Within that mechanism, a high power, pulsed laser beam hits a thin film target. In contrast to the target normal sheath acceleration, the entire film target is accelerated as a bulk by the radiation pressure of the laser. Simulations predict heavy ion beams with kinetic energy up to GeV, as well as solid body densities. However, there are several effects which limit the efficiency of the RPA: On the one hand, the Rayleigh-Taylor-instability limits the predicted density. On the other hand, conventional accelerator elements, such as magnetic focusing devices are too bulky to be installed right after the target. Therefore, we present a new beam transport method, suitable for RPA-like/over-dense plasma beams: laser induced focusing

  16. Ion beam induced fluorescence imaging in biological systems

    International Nuclear Information System (INIS)

    Bettiol, Andrew A.; Mi, Zhaohong; Vanga, Sudheer Kumar; Chen, Ce-belle; Tao, Ye; Watt, Frank

    2015-01-01

    Imaging fluorescence generated by MeV ions in biological systems such as cells and tissue sections requires a high resolution beam (<100 nm), a sensitive detection system and a fluorescent probe that has a high quantum efficiency and low bleaching rate. For cutting edge applications in bioimaging, the fluorescence imaging technique needs to break the optical diffraction limit allowing for sub-cellular structure to be visualized, leading to a better understanding of cellular function. In a nuclear microprobe this resolution requirement can be readily achieved utilizing low beam current techniques such as Scanning Transmission Ion Microscopy (STIM). In recent times, we have been able to extend this capability to fluorescence imaging through the development of a new high efficiency fluorescence detection system, and through the use of new novel fluorescent probes that are resistant to ion beam damage (bleaching). In this paper we demonstrate ion beam induced fluorescence imaging in several biological samples, highlighting the advantages and challenges associated with using this technique

  17. Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

    International Nuclear Information System (INIS)

    Nikolić, S N; Radonjić, M; Krmpot, A J; Lučić, N M; Zlatković, B V; Jelenković, B M

    2013-01-01

    Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a Π laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 . (paper)

  18. Experimental investigation of coupling between widely spaced modes of a beam using higher-order spectra

    International Nuclear Information System (INIS)

    Khan, K.A.

    2001-01-01

    Experimental studies related to a thin isotropic steel beam are presented. The beam was harmonically excited along its axis creating a situation of parametric excitation. A possible two-to-one internal resonance was considered between the third and fourth modes of the beam with an external resonance of its fourth mode. The coupling phenomenon responsible for transfer of energy from high frequency modes to a widely spaced low frequency mode was studied by using conventional tools and higher-order spectra (third-order spectrum (bispectrum) and fourth-order spectrum (trispectrum)). Pointwise dimensions of the attractors were examined to ascertain their chaotic character. The potential of higher-order spectra in detecting the quadratic and cubic phase couplings among the participating modes during bifurcations, periodically modulated motions, and chaotically modulated motions was also examined. The experimental results are provided in the form of power spectra, fractal dimensions, bispectra, bicoherence spectra, and trispectrum. Experimental observations of transitions from periodic to periodically modulated to chaotically-modulated motions are also presented. (author)

  19. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

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

    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...... 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...

  20. Ion and laser beam induced metastable alloy formation

    International Nuclear Information System (INIS)

    Westendorp, J.F.M.

    1986-01-01

    This thesis deals with ion and laser beam induced thin film mixing. It describes the development of an Ultra High Vacuum apparatus for deposition, ion irradiation and in situ analysis of thin film sandwiches. This chamber has been developed in close collaboration with High Voltage Engineering Europa. Thin films can be deposited by an e-gun evaporator. The atom flux is monitored by a quadrupole mass spectrometer. A comparison is made between ion beam and laser mixing of Cu with Au and Cu with W. The comparison provides a better understanding of the relative importance of purely collisional mixing, the role of thermodynamic effects and the contribution of diffusion due to defect generation and migration. (Auth.)

  1. Ion-beam induced structure modifications in amorphous germanium

    International Nuclear Information System (INIS)

    Steinbach, Tobias

    2012-01-01

    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 ε 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 μm 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 ε e HRF =(10.5±1.0) kev nm -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 ε e S a =(12±2) keV nm -1 for the first time extracted for a Ge the characteristic linear behaviour of the

  2. Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator

    Directory of Open Access Journals (Sweden)

    W. An

    2013-10-01

    Full Text Available Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

  3. Preservation of beam loss induced quenches, beam lifetime and beam loss measurements with the HERA-p beam-loss-monitor system

    International Nuclear Information System (INIS)

    Wittenburg, K.

    1994-01-01

    The beam-loss-monitors (BLMs) in the HERA-Proton-ring (HERAp) must fulfil 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. (orig.)

  4. Optically induced rotation of Rayleigh particles by vortex beams with different states of polarization

    International Nuclear Information System (INIS)

    Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Lei, Ming; Yang, Yanlong

    2016-01-01

    Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles. - Highlights: • States of polarization of vortex beams affect the optically induced orbital motion of particles. • The dependences of the force and orbital torque on the topological charge, the size and the absorptivity of particles were calculated. • Focused vortex beams with circular, radial or azimuthal polarizations induce a uniform orbital motion on particles. • Particles experience a non-uniform orbital motion in the focused linearly polarized vortex beam. • The circularly polarized vortex beam is a superior candidate for rotating particles.

  5. Temperature distribution induced by electron beam in a closed cavity

    International Nuclear Information System (INIS)

    Molhem, A.G.; Soulayman, S.Sh.

    2004-01-01

    In order to investigate heat transfer phenomena induced by EB in a closed cavity an experimental arrangement, which allows generating and focusing an electron beam in to closed cavity within 1 mm in diameter and measuring temperature all over any perpendicular section to the EB, is used for this purpose. Experimental data show that the radial distribution of current density and temperature is normal with pressure and location dependent parameters. Moreover, there is two distinguishable regions in the EB: one is central while the other surrounds the first one. (orig.)

  6. Soft X-ray beam induced current technique

    Energy Technology Data Exchange (ETDEWEB)

    Watts, B; Ade, H [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Queen, D; Hellman, F [Department of Physics, University of California, Berkeley, CA 94720 (United States); Kilcoyne, A L D; Tyliszczak, T, E-mail: benjamin.watts@gmail.co [Advanced Light Source, Lawrence Berkeley Nat. Lab., Berkeley, CA 94720 (United States)

    2009-09-01

    Direct mapping of the charge transport efficiency of polymer solar cell devices using a soft X-ray beam induced current (SoXBIC) method is described. By fabricating a polymer solar cell on an x-ray transparent substrate, we demonstrate the ability to map polymer composition and nanoscale structure within an operating solar cell device and to simultaneously measure the local charge transport efficiency via the short-circuit current. A simple model is calculated and compared to experimental SoXBIC data of a PFB:F8BT bulk-heterojunction device in order to gain greater insight into the device operation and physics.

  7. Electron-beam-induced fracture of Kevlar single fibers

    International Nuclear Information System (INIS)

    Dickinson, J.T.; Jensen, L.C.; Klakken, M.L.

    1986-01-01

    We examine the unique situation involving the exposure of polymers to both electron bombardment and mechanical stress. Under certain conditions, crack formation, crack growth, and fracture can occur due to this combination of stimuli. These studies relate to the performance of a number of materials under hostile environments such as space, plasma, and propulsion systems. In this paper we present our initial measurements on the response of single Kevlar fibers loaded in tension to bombardment by 3-keV electrons. We present evidence that the resulting electron-beam-induced fracture is due to bond breaking

  8. Weak-beam electron microscopy of radiation-induced segregation

    International Nuclear Information System (INIS)

    Saka, H.

    1983-01-01

    The segregation of solute atoms to dislocations during irradiation by 1 MeV electrons in a HVEM was studied by measuring the dissociation width of extended dislocations in Cu-5.1 at.%Si, Cu-5.3 at.%Ge, Ag-9.4 at.% In and Ag-9.6 at.%Al alloys. 'Weak-beam' electron microscopy was used. In Cu-Si (oversized solute), Cu-Ge (oversize) and Ag-Al (undersize), solute enrichment was observed near dislocations, while in Ag-In (oversize) solute depletion was observed. The results are discussed in terms of current mechanisms for radiation-induced segregation. (author)

  9. Chromosome aberrations induced by 135 MeV of carbon and neon beams by PRC

    International Nuclear Information System (INIS)

    Ohara, Hiroshi; Minamihisamatu, Masako; Kanai, Tatsuaki; Eguchi-Kasai, Kiyomi; Itsukaichi, Hiromi; Fukutsu, Kumiko; Yatagai, Fumio; Sato, Kohki.

    1993-01-01

    Radiation-induced chromosome aberration can be an indicator of the radiation lesions in irradiated cells. Many studies on chromosome aberration induced by X-ray and γ - ray have indicated that the dose response of the aberration can be fitted to a quadratic equation, Y = αD + βD 2 , and it becomes linear as the LET of beams increases. The main subject of this study was some quantification of chromosomal aberration induced by 135 MeV/n carbon and neon beams produced by the RRC, the operation of which increasingly became useful for the studies on heavy ion biology. The results will meet with some of the radiobiological features connected to the specific action of charged particles. The materials used, the experimental method and the results are reported. Four curves of the dose response for the production of dicentric and ring types of aberration induced by carbon and neon beams and four different dose average LETs are given. Aberration production rate became higher as LET increased. Chromosome aberration can be quantified as an indicator of radiation lesions in the case of high LET particle radiation. (K.I.)

  10. Experimental generation and application of the superposition of higher-order Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-07-01

    Full Text Available Academy of Sciences of Belarus 4 School of Physics, University of Stellenbosch Presented at the 2009 South African Institute of Physics Annual Conference University of KwaZulu-Natal Durban, South Africa 6-10 July 2009 Page 2 © CSIR 2008... www.csir.co.za Generation of Bessel Fields: • METHOD 1: Ring Slit Aperture • METHOD 2: Axicon Adaptation of method 1 to produce superpositions of higher-order Bessel beams: J. Durnin, J.J. Miceli and J.H. Eberly, Phys. Rev. Lett. 58 1499...

  11. Numerical Simulations for the Beam-Induced Electron Cloud in the LHC Beam Screen

    CERN Document Server

    Brüning, Oliver Sim

    1998-01-01

    The following work summarises simulation results obtained at CERN for the beam-induced electron cloud and looks at possible cures for the heat load in the LHC beam screen. The synchrotron radiation in the LHC creates a continuous flow of photoelectrons. These electrons are accelerated by the electric field of the bunch and hit the vacuum chamber on the opposite side of the beam pipe where they crea te secondary electrons which are again accelerated by the next bunch. For a large secondary emission yield the above mechanism leads to an exponential growth of the electron cloud which is limited by space charge forces. The simulations use a two-dimensional mesh for the space charge calculations and include the effect of image charges on the vacuum chamber wall. Depending on the quantum yield for the production of photoelectrons, the secondary emission yield and the reflectivity, the heat load can vary from 0.1 W/m to more than 15 W/m.

  12. 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

    1997-12-31

    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.

  13. 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.

  14. Analysis of charged particle induced reactions for beam monitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Surendra Babu, K. [IOP, Academia Sinica, Taipe, Taiwan (China); Lee, Young-Ouk [Nuclear Data Evaluation Laboratory, Korea Atomic Energy Research Institute (Korea, Republic of); Mukherjee, S., E-mail: smukherjee_msuphy@yahoo.co.in [Department of Physics, Faculty of Science, M.S. University of Baroda, Vadodara 390 002 (India)

    2012-07-15

    The reaction cross sections for different residual nuclides produced in the charged particle (p, d, {sup 3}He and {alpha}) induced reactions were calculated and compared with the existing experimental data which are important for beam monitoring and medical diagnostic applications. A detailed literature compilation and comparison were made on the available data sets for the above reactions. These calculations were carried out using the statistical model code TALYS up to 100 MeV, which contains Kalbach's latest systematic for the emission of complex particles and complex particle-induced reactions. All optical model calculations were performed by ECIS-03, which is built into TALYS. The level density, optical model potential parameters were adjusted to get the better description of experimental data. Various pre-equilibrium models were used in the present calculations with default parameters.

  15. Ion beam induced effects on the ferromagnetism in Pd nanoparticles

    International Nuclear Information System (INIS)

    Kulriya, P. K.; Mehta, B. R.; Agarwal, D. C.; Agarwal, Kanika; Kumar, Praveen; Shivaprasad, S. M.; Avasthi, D. K.

    2012-01-01

    Present study demonstrates the role of metal-insulator interface and ion irradiation induced defects on the ferromagnetic properties of the non-magnetic materials. Magnetic properties of the Pd nanoparticles(NPs) embedded in the a-silica matrix synthesized using atom beam sputtering technique, were determined using SQUID magnetometry measurements which showed that ferromagnetic response of Pd increased by 3.5 times on swift heavy ion(SHI) irradiation. The ferromagnetic behavior of the as-deposited Pd NPs is due to strain induced by the surrounding matrix and modification in the electronic structure at the Pd-silica interface as revealed by insitu XRD and XPS investigations, respectively. The defects created by the SHI bombardment are responsible for enhancement of the magnetization in the Pd NPs.

  16. On induced action for conformal higher spins in curved background

    Energy Technology Data Exchange (ETDEWEB)

    Beccaria, Matteo, E-mail: matteo.beccaria@le.infn.it [Dipartimento di Matematica e Fisica Ennio De Giorgi, Università del Salento & INFN, Via Arnesano, 73100 Lecce (Italy); Tseytlin, Arkady A., E-mail: tseytlin@imperial.ac.uk [The Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2017-06-15

    We continue the investigation of the structure of the action for a tower of conformal higher spin fields in non-trivial 4d background metric recently discussed in Grigoriev and Tseytlin (2016). The action is defined as an induced one from path integral of a conformal scalar field in curved background coupled to higher spin fields. We analyze in detail the dependence of the quadratic part of the induced action on the spin 1 and spin 3 fields, determining the presence of a curvature-dependent mixed spin 1–3 term. One consequence is that the pure spin 3 kinetic term cannot be gauge-invariant on its own beyond the leading term in small curvature expansion. We also compute the non-zero contribution of the 1–3 mixing term to the conformal anomaly c-coefficient. One is thus to determine all such mixing terms before addressing the question of possible vanishing of the total c-coefficient in the conformal higher spin theory.

  17. On induced action for conformal higher spins in curved background

    Directory of Open Access Journals (Sweden)

    Matteo Beccaria

    2017-06-01

    Full Text Available We continue the investigation of the structure of the action for a tower of conformal higher spin fields in non-trivial 4d background metric recently discussed in Grigoriev and Tseytlin (2016 [15]. The action is defined as an induced one from path integral of a conformal scalar field in curved background coupled to higher spin fields. We analyze in detail the dependence of the quadratic part of the induced action on the spin 1 and spin 3 fields, determining the presence of a curvature-dependent mixed spin 1–3 term. One consequence is that the pure spin 3 kinetic term cannot be gauge-invariant on its own beyond the leading term in small curvature expansion. We also compute the non-zero contribution of the 1–3 mixing term to the conformal anomaly c-coefficient. One is thus to determine all such mixing terms before addressing the question of possible vanishing of the total c-coefficient in the conformal higher spin theory.

  18. Laser Induced Breakdown Spectroscopy Based on Single Beam Splitting and Geometric Configuration for Effective Signal Enhancement

    Science.gov (United States)

    Yang, Guang; Lin, Qingyu; Ding, Yu; Tian, Di; Duan, Yixiang

    2015-01-01

    A new laser induced breakdown spectroscopy (LIBS) based on single-beam-splitting (SBS) and proper optical geometric configuration has been initially explored in this work for effective signal enhancement. In order to improve the interaction efficiency of laser energy with the ablated material, a laser beam operated in pulse mode was divided into two streams to ablate/excite the target sample in different directions instead of the conventional one beam excitation in single pulse LIBS (SP-LIBS). In spatial configuration, the laser beam geometry plays an important role in the emission signal enhancement. Thus, an adjustable geometric configuration with variable incident angle between the two splitted laser beams was constructed for achieving maximum signal enhancement. With the optimized angles of 60° and 70° for Al and Cu atomic emission lines at 396.15 nm and 324.75 nm respectively, about 5.6- and 4.8-folds signal enhancements were achieved for aluminum alloy and copper alloy samples compared to SP-LIBS. Furthermore, the temporal analysis, in which the intensity of atomic lines in SP-LIBS decayed at least ten times faster than the SBS-LIBS, proved that the energy coupling efficiency of SBS-LIBS was significantly higher than that of SP-LIBS. PMID:25557721

  19. Generalized melting criterion for beam-induced amorphization

    International Nuclear Information System (INIS)

    Lam, N. Q.; Okamoto, Paul R.

    1993-09-01

    Recent studies have shown that the mean-square static atomic displacements provide a generic measure of the enthalpy stored in the lattice in the form of chemical and topological disorder, and that the effect of the displacements on the softening of shear elastic constants is identical to that of heating. This finding lends support to a generalized form of the Lindemann phenomenological melting criterion and leads to a natural interpretion of crystalline-to-amorphous transformations as defect-induced melting of metastable crystals driven beyond a critical state of disorder where the melting temperature falls below the glass-transition temperature. Application of the generalized Lindemann criterion to both the crystalline and amorphous phases indicates that the enthalpies of the two phases become identical when their shear moduli become equal. This thermo-elastic rule provides a basis for predicting the relative susceptibility of compounds to amorphization in terms of their elastic properties as measured by Debye temperatures. The present approach can explain many of the basic findings on beam-induced amorphization of intermetallic compounds as well as amorphous phase formation associated with ion implantation, ion-beam mixing and other solid-state processes

  20. Ion beam induced surface graphitization of CVD diamond for x-ray beam position monitor applications

    International Nuclear Information System (INIS)

    Liu, Chian; Shu, D.; Kuzay, T.M.; Wen, L.; Melendres, C.A.; Argonne National Lab., IL

    1996-01-01

    The Advanced Photon Source at ANL is a third-generation synchrotron facility that generates powerful x-ray beams on its undulator beamlines. It is important to know the position and angle of the x- ray beam during experiments. Due to very high heat flux levels, several patented x-ray beam position monitors (XBPM) exploiting chemical vapor deposition (CVD) diamond have been developed. These XBPMs have a thin layer of low-atomic-mass metallic coating so that photoemission from the x rays generate a minute but measurable current for position determination. Graphitization of the CVD diamond surface creates a very thin, intrinsic and conducting layer that can stand much higher temperatures and minimal x-ray transmission losses compared to the coated metallic layers. In this paper, a laboratory sputter ion source was used to transform selected surfaces of a CVD diamond substrate into graphite. The effect of 1-5 keV argon ion bombardment on CVD diamond surfaces at various target temperatures from 200 to 500 C was studied using Auger electron spectroscopy and in-situ electrical resistivity measurements. Graphitization after the ion bombardment has been confirmed and optimum conditions for graphitization studied. Raman spectroscopy was used to identify the overall diamond structure in the bulk of CVD diamond substrate after the ion bombardments. It was found that target temperature plays an important role in stability and electrical conductivity of the irradiated CVD diamonds

  1. Higher-order paraxial theory of the propagation of ring rippled laser beam in plasma: Relativistic ponderomotive regime

    International Nuclear Information System (INIS)

    Purohit, Gunjan; Rawat, Priyanka; Chauhan, Prashant; Mahmoud, Saleh T.

    2015-01-01

    This article presents higher-order paraxial theory (non-paraxial theory) for the ring ripple formation on an intense Gaussian laser beam and its propagation in plasma, taking into account the relativistic-ponderomotive nonlinearity. The intensity dependent dielectric constant of the plasma has been determined for the main laser beam and ring ripple superimposed on the main laser beam. The dielectric constant of the plasma is modified due to the contribution of the electric field vector of ring ripple. Nonlinear differential equations have been formulated to examine the growth of ring ripple in plasma, self focusing of main laser beam, and ring rippled laser beam in plasma using higher-order paraxial theory. These equations have been solved numerically for different laser intensities and plasma frequencies. The well established experimental laser and plasma parameters are used in numerical calculation. It is observed that the focusing of the laser beams (main and ring rippled) becomes fast in the nonparaxial region by expanding the eikonal and other relevant quantities up to the fourth power of r. The splitted profile of laser beam in the plasma is observed due to uneven focusing/defocusing of the axial and off-axial rays. The growths of ring ripple increase when the laser beam intensity increases. Furthermore, the intensity profile of ring rippled laser beam gets modified due to the contribution of growth rate

  2. 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.)

  3. Beam-induced backgrounds in detectors at the ILC

    International Nuclear Information System (INIS)

    Vogel, Adrian

    2008-11-01

    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 34 cm -2 s -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.)

  4. An optimized nanoparticle separator enabled by electron beam induced deposition

    International Nuclear Information System (INIS)

    Fowlkes, J D; Rack, P D; Doktycz, M J

    2010-01-01

    Size-based separations technologies will inevitably benefit from advances in nanotechnology. Direct-write nanofabrication provides a useful mechanism for depositing/etching nanoscale elements in environments otherwise inaccessible to conventional nanofabrication techniques. Here, electron beam induced deposition was used to deposit an array of nanoscale features in a 3D environment with minimal material proximity effects outside the beam-interaction region. Specifically, the membrane component of a nanoparticle separator was fabricated by depositing a linear array of sharply tipped nanopillars, with a singular pitch, designed for sub-50 nm nanoparticle permeability. The nanopillar membrane was used in a dual capacity to control the flow of nanoparticles in the transaxial direction of the array while facilitating the sealing of the cellular-sized compartment in the paraxial direction. An optimized growth recipe resulted which (1) maximized the growth efficiency of the membrane (which minimizes proximity effects) and (2) preserved the fidelity of the spacing between nanopillars (which maximizes the size-based gating quality of the membrane) while (3) maintaining sharp nanopillar apexes for impaling an optically transparent polymeric lid critical for device sealing.

  5. Depletion region surface effects in electron beam induced current measurements

    Energy Technology Data Exchange (ETDEWEB)

    Haney, Paul M.; Zhitenev, Nikolai B. [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Yoon, Heayoung P. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Gaury, Benoit [Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Maryland NanoCenter, University of Maryland, College Park, Maryland 20742 (United States)

    2016-09-07

    Electron beam induced current (EBIC) is a powerful characterization technique which offers the high spatial resolution needed to study polycrystalline solar cells. Current models of EBIC assume that excitations in the p-n junction depletion region result in perfect charge collection efficiency. However, we find that in CdTe and Si samples prepared by focused ion beam (FIB) milling, there is a reduced and nonuniform EBIC lineshape for excitations in the depletion region. Motivated by this, we present a model of the EBIC response for excitations in the depletion region which includes the effects of surface recombination from both charge-neutral and charged surfaces. For neutral surfaces, we present a simple analytical formula which describes the numerical data well, while the charged surface response depends qualitatively on the location of the surface Fermi level relative to the bulk Fermi level. We find that the experimental data on FIB-prepared Si solar cells are most consistent with a charged surface and discuss the implications for EBIC experiments on polycrystalline materials.

  6. An optimized nanoparticle separator enabled by electron beam induced deposition

    Science.gov (United States)

    Fowlkes, J. D.; Doktycz, M. J.; Rack, P. D.

    2010-04-01

    Size-based separations technologies will inevitably benefit from advances in nanotechnology. Direct-write nanofabrication provides a useful mechanism for depositing/etching nanoscale elements in environments otherwise inaccessible to conventional nanofabrication techniques. Here, electron beam induced deposition was used to deposit an array of nanoscale features in a 3D environment with minimal material proximity effects outside the beam-interaction region. Specifically, the membrane component of a nanoparticle separator was fabricated by depositing a linear array of sharply tipped nanopillars, with a singular pitch, designed for sub-50 nm nanoparticle permeability. The nanopillar membrane was used in a dual capacity to control the flow of nanoparticles in the transaxial direction of the array while facilitating the sealing of the cellular-sized compartment in the paraxial direction. An optimized growth recipe resulted which (1) maximized the growth efficiency of the membrane (which minimizes proximity effects) and (2) preserved the fidelity of the spacing between nanopillars (which maximizes the size-based gating quality of the membrane) while (3) maintaining sharp nanopillar apexes for impaling an optically transparent polymeric lid critical for device sealing.

  7. Monte Carlo modeling of ion beam induced secondary electrons

    Energy Technology Data Exchange (ETDEWEB)

    Huh, U., E-mail: uhuh@vols.utk.edu [Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840 (United States); Cho, W. [Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996-2100 (United States); Joy, D.C. [Biochemistry & Cellular & Molecular Biology, University of Tennessee, Knoxville, TN 37996-0840 (United States); Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2016-09-15

    Ion induced secondary electrons (iSE) can produce high-resolution images ranging from a few eV to 100 keV over a wide range of materials. The interpretation of such images requires knowledge of the secondary electron yields (iSE δ) for each of the elements and materials present and as a function of the incident beam energy. Experimental data for helium ions are currently limited to 40 elements and six compounds while other ions are not well represented. To overcome this limitation, we propose a simple procedure based on the comprehensive work of Berger et al. Here we show that between the energy range of 10–100 keV the Berger et al. data for elements and compounds can be accurately represented by a single universal curve. The agreement between the limited experimental data that is available and the predictive model is good, and has been found to provide reliable yield data for a wide range of elements and compounds. - Highlights: • The Universal ASTAR Yield Curve was derived from data recently published by NIST. • IONiSE incorporated with the Curve will predict iSE yield for elements and compounds. • This approach can also handle other ion beams by changing basic scattering profile.

  8. Recirculating beam-breakup thresholds for polarized higher-order modes with optical coupling

    Directory of Open Access Journals (Sweden)

    Georg H. Hoffstaetter

    2007-04-01

    Full Text Available Here we will derive the general theory of the beam-breakup (BBU instability in recirculating linear accelerators with coupled beam optics and with polarized higher-order dipole modes. The bunches do not have to be at the same radio-frequency phase during each recirculation turn. This is important for the description of energy recovery linacs (ERLs where beam currents become very large and coupled optics are used on purpose to increase the threshold current. This theory can be used for the analysis of phase errors of recirculated bunches, and of errors in the optical coupling arrangement. It is shown how the threshold current for a given linac can be computed and a remarkable agreement with tracking data is demonstrated. General formulas are then analyzed for several analytically solvable problems: (a Why can different higher order modes (HOM in one cavity couple and why can they then not be considered individually, even when their frequencies are separated by much more than the resonance widths of the HOMs? For the Cornell ERL as an example, it is noted that optimum advantage is taken of coupled optics when the cavities are designed with an x-y HOM frequency splitting of above 50 MHz. The simulated threshold current is then far above the design current of this accelerator. To justify that the simulation can represent an actual accelerator, we simulate cavities with 1 to 8 modes and show that using a limited number of modes is reasonable. (b How does the x-y coupling in the particle optics determine when modes can be considered separately? (c How much of an increase in threshold current can be obtained by coupled optics and why does the threshold current for polarized modes diminish roughly with the square root of the HOMs’ quality factors. Because of this square root scaling, polarized modes with coupled optics increase the threshold current more effectively for cavities that have rather large HOM quality factors, e.g. those without very

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

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pankaj, E-mail: psharma@rtu.ac.in; Parashar, Sandeep Kumar, E-mail: parashar2@yahoo.com [Mechanical Engineering Department, Rajasthan Technical University, Kota (India)

    2016-05-06

    The priority of this paper is to obtain the exact analytical solution for free flexural vibration of FGPM beam actuated using the d{sub 15} effect. In piezoelectric actuators, the potential use of d{sub 15} effect has been of particular interest for engineering applications since shear piezoelectric coefficient d15 is much higher than the other piezoelectric coupling constants d{sub 31} and d{sub 33}. 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.

  10. Electron backscatter diffraction studies of focused ion beam induced phase transformation in cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Jones, H.G., E-mail: helen.jones@npl.co.uk [National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom); Day, A.P. [Aunt Daisy Scientific Ltd, Claremont House, High St, Lydney GL15 5DX (United Kingdom); Cox, D.C. [National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom); Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2016-10-15

    A focused ion beam microscope was used to induce cubic to hexagonal phase transformation in a cobalt alloy, of similar composition to that of the binder phase in a hardmetal, in a controlled manner at 0°, 45° and 80° ion incident angles. The cobalt had an average grain size of ~ 20 μm, allowing multiple orientations to be studied, exposed to a range of doses between 6 × 10{sup 7} and 2 × 10{sup 10} ions/μm{sup 2}. Electron backscatter diffraction (EBSD) was used to determine the original and induced phase orientations, and area fractions, before and after the ion beam exposure. On average, less phase transformation was observed at higher incident angles and after lower ion doses. However there was an orientation effect where grains with an orientation close to (111) planes were most susceptible to phase transformation, and (101) the least, where grains partially and fully transformed at varying ion doses. - Highlights: •Ion-induced phase change in FCC cobalt was observed at multiple incidence angles. •EBSD was used to study the relationship between grain orientation and transformation. •Custom software analysed ion dose and phase change with respect to grain orientation. •A predictive capability of ion-induced phase change in cobalt was enabled.

  11. 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.

  12. Neutralized ion beam modification of cellulose membranes for study of ion charge effect on ion-beam-induced DNA transfer

    Science.gov (United States)

    Prakrajang, K.; Sangwijit, K.; Anuntalabhochai, S.; Wanichapichart, P.; Yu, L. D.

    2012-02-01

    Low-energy ion beam biotechnology (IBBT) has recently been rapidly developed worldwide. Ion-beam-induced DNA transfer is one of the important applications of IBBT. However, mechanisms involved in this application are not yet well understood. In this study plasma-neutralized ion beam was applied to investigate ion charge effect on induction of DNA transfer. Argon ion beam at 7.5 keV was neutralized by RF-driven plasma in the beam path and then bombarded cellulose membranes which were used as the mimetic plant cell envelope. Electrical properties such as impedance and capacitance of the membranes were measured after the bombardment. An in vitro experiment on plasmid DNA transfer through the cellulose membrane was followed up. The results showed that the ion charge input played an important role in the impedance and capacitance changes which would affect DNA transfer. Generally speaking, neutral particle beam bombardment of biologic cells was more effective in inducing DNA transfer than charged ion beam bombardment.

  13. A critical discussion of the vacancy diffusion model of ion beam induced epitaxial crystallization

    International Nuclear Information System (INIS)

    Heera, V.

    1989-01-01

    A simple vacancy diffusion model of ion beam induced epitaxial crystallization of silicon including divacancy formation is developed. The model reproduces some of the experimental findings, as e.g. the dose rate dependence of the crystallization rate. However, the measured activation energy of the ion beam induced epitaxial crystallization cannot be accounted for by vacancy diffusion alone. (author)

  14. Nucleation mechanisms in high energy ion beam induced dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Michael; Garmatter, Daniel; Ferhati, Redi; Amirthapandian, Sankarakumar; Bolse, Wolfgang [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart (Germany)

    2011-07-01

    Solid coatings, when heated above their melting points, often break up by forming small round holes, which then grow, coalesce and finally turn the initially contiguous film into a pattern of isolated droplets. Such dewetting has been intensively studied using thin polymer films on Si. Three different hole nucleation mechanisms were discovered: homogeneous (spontaneous) nucleation, heterogeneous nucleation at defects, and spinodal dewetting by self-amplifying capillary waves. We have recently found that swift heavy ion (SHI) irradiation of thin oxide films on Si results in similar dewetting patterns, even though the films were kept far below their melting points. Using our new in-situ SEM at the UNILAC accelerator of GSI, we were now able to identify the mechanisms behind this SHI induced dewetting phenomenon. By varying the film thickness and introducing defects at the interface, we can directly address the hole nucleation processes. Besides homogeneous and heterogeneous nucleation, we also found a process, which very much resembles the spinodal mechanism found for liquid polymers, although in the present case the instable wavy surface is not generated by capillary waves, but by ion beam induced stresses.

  15. Beam-induced temperature changes in HVEM irradiations

    International Nuclear Information System (INIS)

    Garner, F.A.; Thomas, L.E.; Gelles, D.S.

    1975-01-01

    The peak value of the temperature distribution induced by energy loss of 1.0 MeV electrons in traversing a typical HVEM irradiation specimen can be very substantial. The origin and various features of this distribution were analyzed for a variety of specimen geometries. The major parametric dependencies are shown to be relatively independent of specimen geometry, however, and allow the definition of a scaling relationship that can be employed to predict temperature rises in materials that cannot be measured directly. The use of this scaling relationship requires that the experimenter minimize perturbations of the heat flow due to proximity of the central hole in the specimen. An experimental method of determining directly the magnitude and distribution of beam-induced temperature profiles was developed which utilizes the order-disorder transformation in Fe 3 Al and Cu 3 Au. Scaling of experimentally determined temperature changes leads to more realistic estimates of the total temperature rise than are currently available in various literature tabulations. The factors which determine the optimum selection of irradiation parameters for a given experiment are also discussed

  16. Higher brightness beams from the SPS for the HL-LHC era

    CERN Document Server

    AUTHOR|(CDS)2085448; Bracco, Chiara (CERN)

    The need to push the LHC beyond its limits and increase the deliverable luminosity to the experiments by about one order of magnitude has driven the ongoing injector and HL-LHC upgrades. The higher luminosity requires to increase the beam brightness, which directly translates in the need to adapt the different machine protection systems. Among all the foreseen upgrades, the transfer line collimators (TCDI) and the LHC injection protection systems will be revised. In particular, the guaranteed protection is evaluated in this Ph D work, together with the specification for the minimum shielded aperture in case of injection failures. A detailed model is also developed which insures a more reliable and efficient procedure for the validation of the TCDI setup within the required accuracy. The physics beyond colliders will also be pushed over its current limits in the HL-LHC era. SHiP, a new proposed fixed target experiment served by the SPS is under study. The unprecedented level of requested protons on target per ...

  17. Tunable atom-light beam splitter using electromagnetically induced transparency

    Science.gov (United States)

    Zhu, Xinyu; Wen, Rong; Chen, J. F.

    2018-06-01

    With electromagnetically induced transmission (EIT), an optical field can be converted into collective atomic excitation and stored in the atomic medium through switching off the strong-coupling field adiabatically. By varying the power of the coupling pulse, we can control the ratio between the transmitted optical field and the stored atomic mode. We use a cloud of cold 85Rb atoms prepared in magneto-optical trap as the experimental platform. Based on a model of EIT dark-state polariton, we consider the real case where the atomic medium has a finite length. The theoretical calculation gives numerical results that agree well with the experimental data. The results show that the ratio can be changed approximately from 0 to 100%, when the maximum power of the coupling pulse (the pulse length is 100 ns) varies from 0 to 20 mW, in the cold atomic ensemble with an optical depth of 40. This process can be used to achieve an atom-light hybrid beam splitter with tunable splitting ratio and thus find potential application in interferometric measurement and quantum information processing.

  18. The influence of beam divergence on ion-beam induced surface patterns

    International Nuclear Information System (INIS)

    Kree, R.; Yasseri, T.; Hartmann, A.K.

    2009-01-01

    We present a continuum theory and a Monte Carlo model of self-organized surface pattern formation by ion-beam sputtering including effects of beam profiles. Recently, it has turned out that such secondary ion-beam parameters may have a strong influence on the types of emerging patterns. We first discuss several cases, for which beam profiles lead to random parameters in the theory of pattern formation. Subsequently we study the evolution of the averaged height profile in continuum theory and find that the typical Bradley-Harper scenario of dependence of ripple patterns on the angle of incidence can be changed qualitatively. Beam profiles are implemented in Monte Carlo simulations, where we find generic effects on pattern formation. Finally, we demonstrate that realistic beam profiles, taken from experiments, may lead to qualitative changes of surface patterns.

  19. Compensation of head-on beam-beam induced resonance driving terms and tune spread in the Relativistic Heavy Ion Collider

    Directory of Open Access Journals (Sweden)

    W. Fischer

    2017-09-01

    Full Text Available A head-on beam-beam compensation scheme was implemented for operation in the Relativistic Heavy Ion Collider (RHIC at Brookhaven National Laboratory [Phys. Rev. Lett. 115, 264801 (2015PRLTAO0031-900710.1103/PhysRevLett.115.264801]. The compensation consists of electron lenses for the reduction of the beam-beam induced tune spread, and a lattice for the minimization of beam-beam generated resonance driving terms. We describe the implementations of the lattice and electron lenses, and report on measurements of lattice properties and the effect of the electron lenses on the hadron beam.

  20. Intense heavy ion beam-induced effects in carbon-based stripper foils

    Energy Technology Data Exchange (ETDEWEB)

    Kupka, Katharina

    2016-08-15

    Amorphous carbon or carbon-based stripper foils are commonly applied in accelerator technology for electron stripping of ions. At the planned facility for antiproton and ion research (FAIR) at the Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt, thin carbon stripper foils provide an option for directly delivering ions of intermediate charge states to the heavy ion synchrotron, SIS 18, in order to mitigate space charge limitations during high-intensity operation. In case of desired high end-energies in the synchrotron, a second stripping process by a thicker carbon foil provides ions of higher charge states for injection into the SIS18. High beam intensities and a pulsed beam structure as foreseen at FAIR pose new challenges to the stripper foils which experience enhanced degradation by radiation damage, thermal effects, and stress waves. In order to ensure reliable accelerator operation, radiation-hard stripper foils are required. This thesis aims to a better understanding of processes leading to degradation of carbon-based thin foils. Special focus is placed on ion-beam induced structure and physical property changes and on the influence of different beam parameters. Irradiation experiments were performed at the M3-beamline of the universal linear accelerator (UNILAC) at GSI, using swift heavy ion beams with different pulse lengths and repetition rates. Tested carbon foils were standard amorphous carbon stripper foils produced by the GSI target laboratory, as well as commercial amorphous and diamond-like carbon foils and buckypaper foils. Microstructural changes were investigated with various methods such as optical microscopy, scanning electron microscopy (SEM), profilometry and chromatic aberration measurements. For the investigation of structural changes X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), in-situ Fourier-transform infrared spectroscopy (FTIR) and small angle X

  1. Intense heavy ion beam-induced effects in carbon-based stripper foils

    International Nuclear Information System (INIS)

    Kupka, Katharina

    2016-08-01

    Amorphous carbon or carbon-based stripper foils are commonly applied in accelerator technology for electron stripping of ions. At the planned facility for antiproton and ion research (FAIR) at the Helmholtzzentrum fuer Schwerionenforschung (GSI), Darmstadt, thin carbon stripper foils provide an option for directly delivering ions of intermediate charge states to the heavy ion synchrotron, SIS 18, in order to mitigate space charge limitations during high-intensity operation. In case of desired high end-energies in the synchrotron, a second stripping process by a thicker carbon foil provides ions of higher charge states for injection into the SIS18. High beam intensities and a pulsed beam structure as foreseen at FAIR pose new challenges to the stripper foils which experience enhanced degradation by radiation damage, thermal effects, and stress waves. In order to ensure reliable accelerator operation, radiation-hard stripper foils are required. This thesis aims to a better understanding of processes leading to degradation of carbon-based thin foils. Special focus is placed on ion-beam induced structure and physical property changes and on the influence of different beam parameters. Irradiation experiments were performed at the M3-beamline of the universal linear accelerator (UNILAC) at GSI, using swift heavy ion beams with different pulse lengths and repetition rates. Tested carbon foils were standard amorphous carbon stripper foils produced by the GSI target laboratory, as well as commercial amorphous and diamond-like carbon foils and buckypaper foils. Microstructural changes were investigated with various methods such as optical microscopy, scanning electron microscopy (SEM), profilometry and chromatic aberration measurements. For the investigation of structural changes X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), in-situ Fourier-transform infrared spectroscopy (FTIR) and small angle X

  2. Vortex phase-induced changes of the statistical properties of a partially coherent radially polarized beam.

    Science.gov (United States)

    Guo, Lina; Chen, Yahong; Liu, Xianlong; Liu, Lin; Cai, Yangjian

    2016-06-27

    Partially coherent radially polarized (PCRP) beam was introduced and generated in recent years. In this paper, we investigate the statistical properties of a PCRP beam embedded with a vortex phase (i.e., PCRP vortex beam). We derive the analytical formula for the cross-spectral density matrix of a PCRP vortex beam propagating through a paraxial ABCD optical system and analyze the statistical properties of a PCRP vortex beam focused by a thin lens. It is found that the statistical properties of a PCRP vortex beam on propagation are much different from those of a PCRP beam. The vortex phase induces not only the rotation of the beam spot, but also the changes of the beam shape, the degree of polarization and the state of polarization. We also find that the vortex phase plays a role of resisting the coherence-induced degradation of the intensity distribution and the coherence-induced depolarization. Furthermore, we report experimental generation of a PCRP vortex beam for the first time. Our results will be useful for trapping and rotating particles, free-space optical communications and detection of phase object.

  3. Ion beam induced defects in solids studied by optical techniques

    International Nuclear Information System (INIS)

    Comins, J.D.; Amolo, G.O.; Derry, T.E.; Connell, S.H.; Erasmus, R.M.; Witcomb, M.J.

    2009-01-01

    Optical methods can provide important insights into the mechanisms and consequences of ion beam interactions with solids. This is illustrated by four distinctly different systems. X- and Y-cut LiNbO 3 crystals implanted with 8 MeV Au 3+ ions with a fluence of 1 x 10 17 ions/cm 2 result in gold nanoparticle formation during high temperature annealing. Optical extinction curves simulated by the Mie theory provide the average nanoparticle sizes. TEM studies are in reasonable agreement and confirm a near-spherical nanoparticle shape but with surface facets. Large temperature differences in the nanoparticle creation in the X- and Y-cut crystals are explained by recrystallisation of the initially amorphised regions so as to recreate the prior crystal structure and to result in anisotropic diffusion of the implanted gold. Defect formation in alkali halides using ion beam irradiation has provided new information. Radiation-hard CsI crystals bombarded with 1 MeV protons at 300 K successfully produce F-type centres and V-centres having the I 3 - structure as identified by optical absorption and Raman studies. The results are discussed in relation to the formation of interstitial iodine aggregates of various types in alkali iodides. Depth profiling of I 3 - and I 5 - aggregates created in RbI bombarded with 13.6 MeV/A argon ions at 300 K is discussed. The recrystallisation of an amorphous silicon layer created in crystalline silicon bombarded with 100 keV carbon ions with a fluence of 5 x 10 17 ions/cm 2 during subsequent high temperature annealing is studied by Raman and Brillouin light scattering. Irradiation of tin-doped indium oxide (ITO) films with 1 MeV protons with fluences from 1 x 10 15 to 250 x 10 15 ions/cm -2 induces visible darkening over a broad spectral region that shows three stages of development. This is attributed to the formation of defect clusters by a model of defect growth and also high fluence optical absorption studies. X-ray diffraction studies show

  4. Ion beam induced defects in solids studied by optical techniques

    Science.gov (United States)

    Comins, J. D.; Amolo, G. O.; Derry, T. E.; Connell, S. H.; Erasmus, R. M.; Witcomb, M. J.

    2009-08-01

    Optical methods can provide important insights into the mechanisms and consequences of ion beam interactions with solids. This is illustrated by four distinctly different systems. X- and Y-cut LiNbO 3 crystals implanted with 8 MeV Au 3+ ions with a fluence of 1 × 10 17 ions/cm 2 result in gold nanoparticle formation during high temperature annealing. Optical extinction curves simulated by the Mie theory provide the average nanoparticle sizes. TEM studies are in reasonable agreement and confirm a near-spherical nanoparticle shape but with surface facets. Large temperature differences in the nanoparticle creation in the X- and Y-cut crystals are explained by recrystallisation of the initially amorphised regions so as to recreate the prior crystal structure and to result in anisotropic diffusion of the implanted gold. Defect formation in alkali halides using ion beam irradiation has provided new information. Radiation-hard CsI crystals bombarded with 1 MeV protons at 300 K successfully produce F-type centres and V-centres having the I3- structure as identified by optical absorption and Raman studies. The results are discussed in relation to the formation of interstitial iodine aggregates of various types in alkali iodides. Depth profiling of I3- and I5- aggregates created in RbI bombarded with 13.6 MeV/A argon ions at 300 K is discussed. The recrystallisation of an amorphous silicon layer created in crystalline silicon bombarded with 100 keV carbon ions with a fluence of 5 × 10 17 ions/cm 2 during subsequent high temperature annealing is studied by Raman and Brillouin light scattering. Irradiation of tin-doped indium oxide (ITO) films with 1 MeV protons with fluences from 1 × 10 15 to 250 × 10 15 ions/cm -2 induces visible darkening over a broad spectral region that shows three stages of development. This is attributed to the formation of defect clusters by a model of defect growth and also high fluence optical absorption studies. X-ray diffraction studies show

  5. Beam-induced heat loads on the beam screens of the inner triplets for the HL-LHC

    CERN Document Server

    Skripka, Galina; CERN. Geneva. ATS Department

    2018-01-01

    The expected heat load induced on the beam screens has been evaluated for the triplet assemblies in the four experimental Insertion Regions (IRs) of the HL-LHC. The contribution from electron cloud effects has been estimated using PyECLOUD macroparticle simulations. The presence of a surface treatment for the reduction of the Secondary Electron Yield has been taken into account. The contribution from the impedance of the beam screen has been evaluated taking into account the impact of the temperature and of the magnetic field on the resistivity of the surface.

  6. The status and new trends of ion beam induced charge technique

    International Nuclear Information System (INIS)

    Lu Rongrong; Qiu Huiyuan; Zhu Dezhang

    2002-01-01

    Ion beam induced charge technique (IBIC) with low beam current (fA level) and high efficiency is a new development of nuclear microscopy. It has been widely applied to the fields of semiconductor and microelectronic materials. The principle and the experimental method of the IBIC technique were described and reviewed its status and new trends were reviewed

  7. Electron beam induced fluorescence measurements of the degree of hydrogen dissociation in hydrogen plasmas

    NARCIS (Netherlands)

    Smit, C.; Brussaard, G.J.H.; de Beer, E.C.M.; Schram, D.C.; Sanden, van de M.C.M.

    2004-01-01

    The degree of dissociation of hydrogen in a hydrogen plasma has been measured using electron beam induced fluorescence. A 20 kV, 1 mA electron beam excites both the ground state H atom and H2 molecule into atomic hydrogen in an excited state. From the resulting fluorescence the degree of

  8. A proposal for study of ion-beam induced chemical reactions using JAERI tandem accelerator

    International Nuclear Information System (INIS)

    1985-11-01

    Problems in ion-beam induced chemical reactions using JAERI Tandem Accelerator were discussed. Research philosophy, some proposed experiments which are based on measurements during ion-beam bombardment, and main features of the experimental apparatus are briefly described in this report. (author)

  9. THE EFFECTS OF ELECTRON-BEAM-INDUCED ELECTRIC FIELD ON THE GENERATION OF LANGMUIR TURBULENCE IN FLARING ATMOSPHERES

    International Nuclear Information System (INIS)

    Zharkova, Valentina V.; Siversky, Taras V.

    2011-01-01

    The precipitation of an electron beam injected into the solar atmosphere is studied for the generation of Langmuir wave turbulence in the presence of collisional and Ohmic losses. The system of quasi-linear time-dependent kinetic equations describing the evolution of beams and Langmuir waves is solved by using the summary approximation method. It is found that at upper atmospheric levels the self-induced electric field suppresses the generation of Langmuir turbulence to very small regions below injection. With further precipitation into deeper atmosphere the initial single power-law distributions of beam electrons are transformed into energy distributions with maxima at lower energies formed by collisional and Ohmic energy depletion. The electrons with lower energies (<20 keV) generate on large spatial scales intense low-hybrid and high-hybrid Langmuir waves with well-defined patterns in the corona while higher energy electrons generate moderate low-hybrid waves in the chromosphere. The maximum wave density appears at the maximum of the ambient density. The self-induced electric field reduces the level and makes the regions with low-hybrid Langmuir turbulence narrower in the corona and upper chromosphere. The higher the beam energy flux or its self-induced electric field, the narrower the regions with Langmuir turbulence. High-hybrid Langmuir waves in the form of multiple patterns in space (in the corona) and energy (below 20 keV) are found to be generated only by a very intense electron beam. The number of patterns in both dimensions is also shown to be significantly reduced by the self-induced electric field.

  10. Intensity-gradient induced Sisyphus cooling of a single atom in a localized hollow-beam trap

    International Nuclear Information System (INIS)

    Yin, Yaling; Xia, Yong; Ren, Ruimin; Du, Xiangli; Yin, Jianping

    2015-01-01

    In order to realize a convenient and efficient laser cooling of a single atom, we propose a simple and promising scheme to cool a single neutral atom in a blue-detuned localized hollow-beam trap by intensity-gradient induced Sisyphus cooling, and study the dynamic process of the intensity-gradient cooling of a single 87 Rb atom in the localized hollow-beam trap by using Monte-Carlo simulations. Our study shows that a single 87 Rb atom with a temperature of 120 μK from a magneto-optical trap (MOT) can be directly cooled to a final temperature of 4.64 μK in our proposed scheme. We also investigate the dependences of the cooling results on the laser detuning δ of the localized hollow-beam, the power RP 0 of the re-pumping laser beam, the sizes of both the localized hollow-beam and the re-pumping beam, and find that there is a pair of optimal cooling parameters (δ and RP 0 ) for an expected lowest temperature, and the cooling results strongly depend on the size of the re-pumping beam, but weakly depend on the size of the localized hollow-beam. Finally, we further study the cooling potential of our localized hollow-beam trap for the initial temperature of a single atom, and find that a single 87 Rb atom with an initial temperature of higher than 1 mK can also be cooled directly to about 6.6 μK. (paper)

  11. Underling modification in ion beam induced Si wafers

    International Nuclear Information System (INIS)

    Hazra, S.; Chini, T.K.; Sanyal, M.K.; Grenzer, J.; Pietsch, U.

    2005-01-01

    Subsurface (amorphous-crystalline interface) structure of keV ion beam modified Si(001) wafers was studied for the first time using non-destructive technique and compared with that of the top one. Ion-beam modifications of the Si samples were done using state-of-art high-current ion implanter facility at Saha Institute of Nuclear Physics by changing energy, dose and angle of incidence of the Ar + ion beam. To bring out the underlying modification depth-resolved x-ray grazing incidence diffraction has been carried out using synchrotron radiation facility, while the structure of the top surface was studied through atomic force microscopy

  12. Selective excitation of higher-radial-order Laguerre-Gaussian beams using a solid-state digital laser

    CSIR Research Space (South Africa)

    Bell, Teboho

    2017-01-01

    Full Text Available Filter (LF) was introduced to only transmit 1064 nm and block the 808 nm pump. The laser beam was transmitted out of the cavity through an output coupler mirror (M3 on Figure 1) and was 1:1 relay imaged using two 125 mm lenses (L3 and L4) to a Photon...; Published December 30, 2016 Citation: Bell T, Ngcobo S (2016) Selective Excitation of Higher-radial-order Laguerre-Gaussian Beams Using a Solid-state Digital Laser. J Laser Opt Photonics 3: 144. doi: 10.4172/2469-410X.1000144 Copyright: © 2016 Bell T, et...

  13. Surface Resistance Measurements and Estimate of the Beam-Induced Resistive Wall Heating of the LHC Dipole Beam Screen

    CERN Document Server

    Caspers, Friedhelm; Ruggiero, F; Tan, J

    1999-01-01

    An estimate of the resistive losses in the LHC beam screen is given from cold surface resistance measurements using the shielded pair technique, with particular emphasis on the effect of a high magnetic field. Two different copper coating methods, namely electro-deposition and co-lamination, have been evaluated. Experimental data are compared with theories including the anomalous skin effect and the magneto-resistance effect. It is shown whether the theory underestimates or not the losses depends strongly on the RRR value, on the magnetic field and on the surface characteristics. In the pessimistic case and for nominal machine parameters, the estimated beam-induced resistive wall heating can be as large as 260 mW/m for two circulating beams.

  14. Transverse Space-Charge Field-Induced Plasma Dynamics for Ultraintense Electron-Beam Characterization

    Directory of Open Access Journals (Sweden)

    R. Tarkeshian

    2018-05-01

    Full Text Available Similarly to laser or x-ray beams, the interaction of sufficiently intense particle beams with neutral gases will result in the creation of plasma. In contrast to photon-based ionization, the strong unipolar field of a particle beam can generate a plasma where the electron population receives a large initial momentum kick and escapes, leaving behind unshielded ions. Measuring the properties of the ensuing Coulomb exploding ions—such as their kinetic energy distribution, yield, and spatial distribution—can provide information about the peak electric fields that are achieved in the electron beams. Particle-in-cell simulations and analytical models are presented for high-brightness electron beams of a few femtoseconds or even hundreds of attoseconds, and transverse beam sizes on the micron scale, as generated by today’s free electron lasers. Different density regimes for the utilization as a potential diagnostics are explored, and the fundamental differences in plasma dynamical behavior for e-beam or photon-based ionization are highlighted. By measuring the dynamics of field-induced ions for different gas and beam densities, a lower bound on the beam charge density can be obtained in a single shot and in a noninvasive way. The exponential dependency of the ionization yield on the beam properties can provide unprecedented spatial and temporal resolution, at the submicrometer and subfemtosecond scales, respectively, offering a practical and powerful approach to characterizing beams from accelerators at the frontiers of performance.

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

    Science.gov (United States)

    Deng, Yongfeng; Jiang, Jian; Han, Xianwei; Tan, Chang; Wei, Jianguo

    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.

  16. Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities

    Directory of Open Access Journals (Sweden)

    A. H. Lumpkin

    2018-06-01

    Full Text Available We report the direct observations of submacropulse beam centroid oscillations correlated with higher order modes (HOMs which were generated by off-axis electron beam steering in TESLA-type superconducting rf cavities. The experiments were performed at the Fermilab Accelerator Science and Technology (FAST facility using its unique configuration of a photocathode rf gun injecting beam into two separated nine-cell cavities in series with corrector magnets and beam position monitors (BPMs located before, between, and after them. Oscillations of ∼100  kHz in the vertical plane and ∼380  kHz in the horizontal plane with up to 600-μm amplitudes were observed in a 3-MHz micropulse repetition rate beam with charges of 100, 300, 500, and 1000  pC/b. However, the effects were much reduced at 100  pC/b. The measurements were based on HOM detector circuitry targeting the first and second dipole passbands, rf BPM bunch-by-bunch array data, imaging cameras, and a framing camera. Calculations reproduced the oscillation frequencies of the phenomena in the vertical case. In principle, these fundamental results may be scaled to cryomodule configurations of major accelerator facilities.

  17. Tunable atomic force microscopy bias lithography on electron beam induced carbonaceous platforms

    Directory of Open Access Journals (Sweden)

    Narendra Kurra

    2013-09-01

    Full Text Available Tunable local electrochemical and physical modifications on the carbonaceous platforms are achieved using Atomic force microscope (AFM bias lithography. These carbonaceous platforms are produced on Si substrate by the technique called electron beam induced carbonaceous deposition (EBICD. EBICD is composed of functionalized carbon species, confirmed through X-ray photoelectron spectroscopy (XPS analysis. AFM bias lithography in tapping mode with a positive tip bias resulted in the nucleation of attoliter water on the EBICD surface under moderate humidity conditions (45%. While the lithography in the contact mode with a negative tip bias caused the electrochemical modifications such as anodic oxidation and etching of the EBICD under moderate (45% and higher (60% humidity conditions respectively. Finally, reversible charge patterns are created on these EBICD surfaces under low (30% humidity conditions and investigated by means of electrostatic force microscopy (EFM.

  18. Beam-induced pressure variations in a TFTR neutral-beam injector

    International Nuclear Information System (INIS)

    Willis, J.E.; Berkner, K.H.

    1981-10-01

    In neutral-beam injection systems either all or part of the gas flow into the neutralizer comes from the plasma source. When the beam is switched on, ions from the plasma source, which used to contribute to the gas flow, are converted to an energetic beam and are pumped away: hence reducing the gas input to the neutralizer. The large volume of the neutralizer and its high conductance damp out rapid changes; for example, when the gas to the source is first turned on, there is a 230 msec exponential rise time associated with pressure in the neutralizer. The neutralizer in turn acts as a source of gas to the first chamber and the first chamber to the second and so on. Beam dumps become additional sources of gas in the second chamber and target tank as gas molecules are collisionally desorbed from the surface of the dump. A simple analytical model (the equivalent of an electrical RC circuit) of the volumes and conductances of the system has been used to describe the pressure variations. The use of time dependent sources terms in the model gives an estimate of the desorption rate from the dumps and its time variation during a beam pulse

  19. 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

    1994-12-31

    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.

  20. Analysis of mutagenic effects induced by carbon beams at different LET in a red yeast strain

    International Nuclear Information System (INIS)

    Sun Haining; Wang Jufang; Ma Shuang; Lu Dong; Wu Xin; Li Wenjian

    2011-01-01

    To evaluate inactive and mutagenic effects of carbon beam at different LET, the inactivation cross section and mutation cross section induced by carbon beams of different LET values were investigated in a red yeast strain Rhodotorula glutinis AY 91015. It was found that the maximum inactivation cross section of 4.37μm 2 , which was very close to the average nucleus cross section, was at LET of 120.0 keV/μm. The maximum mutation cross section was at LET of 96.0 keV/μm. Meanwhile, the highest mutagenicity of carbon ion was found around 58.2 keV/μm. It implied that the most efficient LET to induce mutation in survival yeasts was 58.2 keV/μm, which corresponded to energy of 35 MeV/u carbon beam. The most effective carbon beam to induce inactivation and mutation located at different energy region. (authors)

  1. 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.

  2. Study on THz wave generation from air plasma induced by quasi-square Airy beam

    Science.gov (United States)

    Zhang, Shijing; Zhang, Liangliang; Jiang, Guangtong; Zhang, Cunlin; Zhao, Yuejin

    2018-01-01

    Terahertz (THz) wave has attracted considerable attention in recent years because of its potential applications. The intense THz waves generated from air plasma induced by two-color femtosecond laser are widely used due to its high generation efficiency and broad frequency bandwidth. The parameters of the laser change the distribution of the air plasma, and then affect the generation of THz wave. In this research, we investigate the THz wave generation from air plasma induced by quasi-square Airy beam. Unlike the common Gauss beam, the quasi-square Airy beam has ability to autofocus and to increase the maximum intensity at the focus. By using the spatial light modulator (SLM), we can change the parameters of phase map to control the shape of the Airy beam. We obtain the two-color laser field by a 100-um-thick BBO crystal, then use a Golay detector to record THz wave energy. By comparing terahertz generation at different modulation depths, we find that terahertz energy produced by quasi-square Airy beam is up to 3.1 times stronger than that of Gauss beam with identical laser energy. In order to understand the influence of quasi-square Airy beam on the BBO crystal, we record THz wave energy by changing the azimuthal angle of BBO crystal with Gauss beam and Airy beam at different modulation depths. We find that the trend of terahertz energy with respect to the azimuthal angle of the BBO crystal keeps the same for different laser beams. We believe that the quasi-square Airy beam or other auto focusing beam can significantly improve the efficiency of terahertz wave generation and pave the way for its applications.

  3. Turbulence-induced persistence in laser beam wandering.

    Science.gov (United States)

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

    2015-07-01

    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.

  4. Beam induced hydrodynamic tunneling in the future circular collider components

    Directory of Open Access Journals (Sweden)

    N. A. Tahir

    2016-08-01

    Full Text Available 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.

  5. 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.

  6. Laser induced fluorescence spectroscopy in atomic beams of radioactive nuclides

    International Nuclear Information System (INIS)

    Rebel, H.; Schatz, G.

    1982-01-01

    Measurements of the resonant scattering of light from CW tunable dye lasers, by a well collimated atomic beam, enable hyperfine splittings and optical isotope shifts to be determined with high precision and high sensitivity. Recent off-line atomic beam experiments with minute samples, comprising measurements with stable and unstable Ba, Ca and Pb isotopes are reviewed. The experimental methods and the analysis of the data are discussed. Information on the variation of the rms charge radii and on electromagnetic moments of nuclei in long isotopic chains is presented. (orig.) [de

  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. Stability of higher-order longitudinal modes in a bunched beam without mode coupling

    International Nuclear Information System (INIS)

    Satoh, K.

    1981-05-01

    The theory of longitudinal instabilities of bunched beams was proposed by F. Sacherer. Starting from the Vlasov equation, he derived the integral equation for the perturbed distribution function. While the general method to solve the integral equation was given by Sacherer, a number of other papers discussing longitudinal bunched beam instability have also been published. Here we want to propose another formalism with which we can treat the integral equation without mode coupling for the case of a Gaussian bunch. We then generalize the formalism for the other bunch distributions, and derive a practical method to analyze the instability for the case of a parabolic bunch. While the solution of the Sacherer equation that we find is not new, we present another approach to solve it. Since the integral equation for the transverse instability is similar to that for the longitudinal instability, this formalism is also useful for the transverse case. 12 figs., 4 figs

  9. Impact of large beam-induced heat loads on the transient operation of the beam screens and the cryogenic plants of the Future Circular Collider (FCC)

    Science.gov (United States)

    Correia Rodrigues, H.; Tavian, L.

    2017-12-01

    The Future Circular Collider (FCC) under study at CERN will produce 50-TeV high-energy proton beams. The high-energy particle beams are bent by 16-T superconducting dipole magnets operating at 1.9 K and distributed over a circumference of 80 km. The circulating beams induce 5 MW of dynamic heat loads by several processes such as synchrotron radiation, resistive dissipation of beam image currents and electron clouds. These beam-induced heat loads will be intercepted by beam screens operating between 40 and 60 K and induce transients during beam injection. Energy ramp-up and beam dumping on the distributed beam-screen cooling loops, the sector cryogenic plants and the dedicated circulators. Based on the current baseline parameters, numerical simulations of the fluid flow in the cryogenic distribution system during a beam operation cycle were performed. The effects of the thermal inertia of the headers on the helium flow temperature at the cryogenic plant inlet as well as the temperature gradient experienced by the beam screen has been assessed. Additionally, this work enabled a thorough exergetic analysis of different cryogenic plant configurations and laid the building-block for establishing design specification of cold and warm circulators.

  10. Observation of helium flow induced beam orbit oscillations at RHIC

    International Nuclear Information System (INIS)

    Montag, C.; Bonati, R.; Brennan, J.M.; Butler, J.; Cameron, P.; Ganetis, G.; He, P.; Hirzel, W.; Jia, L.X.; Koello, P.; Louie, W.; McIntyre, G.; Nicoletti, A.; Rank, J.; Roser, T.; Satogata, T.; Schmalzle, J.; Sidi-Yekhlef, A.; Sondericker, J.; Tallerico, T.

    2006-01-01

    Horizontal beam orbit jitter at frequencies around 10 Hz has been observed at RHIC for several years. The distinct frequencies of this jitter have been found at superconducting low-beta quadrupole triplet magnets around the ring, where they coincide with mechanical vibration modes of the cold masses. Recently, we have identified liquid helium flow as the driving force of these oscillations

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

    CERN Document Server

    AUTHOR|(CDS)2083092; Burkart, Florian; 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...

  12. Laser beam shaping for studying thermally induced damage

    CSIR Research Space (South Africa)

    Masina, BN

    2011-08-01

    Full Text Available into a flat-top beam profile by using a diffractive optical element as a phase element in conjunction with a Fourier transforming lens. In this paper, they have successfully demonstrated temperature profiles across the diamond tool surface using two laser...

  13. 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.

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

    International Nuclear Information System (INIS)

    Evora, M.C.; Araujo, J.R.; Ferreira, E.H.M.; Strohmeier, B.R.; Silva, L.G.A.; Achete, C.A.

    2015-01-01

    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 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 4 ·7H 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

  15. 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.)

  16. Is low-energy-ion bombardment generated X-ray emission a secondary mutational source to ion-beam-induced genetic mutation?

    Energy Technology Data Exchange (ETDEWEB)

    Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (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); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Thopan, P.; Yaopromsiri, C. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Detected X-ray emission from metal, plastic and biological samples. ► Characteristic X-ray emission was detected from metal but not from non-metals. ► Low-energy ion bombarded bacteria held in different sample holders. ► Bacteria held in metal holder had higher mutation rate than in plastic holder. ► Ion-beam-induced X-ray from biological sample is not a basic mutation source. -- Abstract: Low-energy ion beam biotechnology has achieved tremendous successes in inducing crop mutation and gene transfer. However, mechanisms involved in the related processes are not yet well understood. In ion-beam-induced mutation, ion-bombardment-produced X-ray has been proposed to be one of the secondary mutation sources, but the speculation has not yet been experimentally tested. We carried out this investigation to test whether the low-energy ion-beam-produced X-ray was a source of ion-beam-induced mutation. In the investigation, X-ray emission from 29-keV nitrogen- or argon- ion beam bombarded bacterial Escherichia coli (E. coli) cells held in a metal or plastic sample holder was in situ detected using a highly sensitive X-ray detector. The ion beam bombarded bacterial cells held in different material holders were observed for mutation induction. The results led to a conclusion that secondary X-ray emitted from ion-beam-bombarded biological living materials themselves was not a, or at least a negligible, mutational source, but the ion-beam-induced X-ray emission from the metal that made the sample holder could be a source of mutation.

  17. Is low-energy-ion bombardment generated X-ray emission a secondary mutational source to ion-beam-induced genetic mutation?

    International Nuclear Information System (INIS)

    Thongkumkoon, P.; Prakrajang, K.; Thopan, P.; Yaopromsiri, C.; Suwannakachorn, D.; Yu, L.D.

    2013-01-01

    Highlights: ► Detected X-ray emission from metal, plastic and biological samples. ► Characteristic X-ray emission was detected from metal but not from non-metals. ► Low-energy ion bombarded bacteria held in different sample holders. ► Bacteria held in metal holder had higher mutation rate than in plastic holder. ► Ion-beam-induced X-ray from biological sample is not a basic mutation source. -- Abstract: Low-energy ion beam biotechnology has achieved tremendous successes in inducing crop mutation and gene transfer. However, mechanisms involved in the related processes are not yet well understood. In ion-beam-induced mutation, ion-bombardment-produced X-ray has been proposed to be one of the secondary mutation sources, but the speculation has not yet been experimentally tested. We carried out this investigation to test whether the low-energy ion-beam-produced X-ray was a source of ion-beam-induced mutation. In the investigation, X-ray emission from 29-keV nitrogen- or argon- ion beam bombarded bacterial Escherichia coli (E. coli) cells held in a metal or plastic sample holder was in situ detected using a highly sensitive X-ray detector. The ion beam bombarded bacterial cells held in different material holders were observed for mutation induction. The results led to a conclusion that secondary X-ray emitted from ion-beam-bombarded biological living materials themselves was not a, or at least a negligible, mutational source, but the ion-beam-induced X-ray emission from the metal that made the sample holder could be a source of mutation

  18. Summary and presentation of the international workshop on beam induced energy deposition (issues, concerns, solutions)

    International Nuclear Information System (INIS)

    Soundranayagam, R.

    1991-11-01

    This report discusses: energy deposition and radiation shielding in antriproton source at FNAL; radiation issues/problems at RHIC; radiation damage to polymers; radiation effects on optical fibre in the SSC tunnel; capabilities of the Brookhaven Radiation Effects Facility; the SSC interaction region; the FLUKA code system, modifications, recent extension and experimental verification; energy particle transport calculations and comparisons with experimental data; Los Alamos High Energy Transport code system; MCNP features and applications; intercomparison of Monte Carlo codes designed for simulation of high energy hadronic cascades; event generator, DTUJET-90 and DTUNUC; Preliminary hydrodynamic calculations of beam energy deposition; MESA code calculations of material response to explosive energy deposition; Smooth particle hydrodynamic; hydrodynamic effects and mass depletion phenomena in targets; beam dump: Beam sweeping and spoilers; Design considerations to mitigate effects of accidental beam dump; SSC beam abort and absorbed; beam abort system of SSC options; unconventional scheme for beam spoilers; low β quadrupoles: Energy deposition and radioactivation; beam induces energy deposition in the SSC components; extension of SSC-SR-1033 approach to radioactivation in LHC and SSC detectors; energy deposition in the SSC low-β IR-quads; beam losses and collimation in the LHC; and radiation shielding around scrapers

  19. Transmutation prospect of long-lived nuclear waste induced by high-charge electron beam from laser plasma accelerator

    Science.gov (United States)

    Wang, X. L.; Xu, Z. Y.; Luo, W.; Lu, H. Y.; Zhu, Z. C.; Yan, X. Q.

    2017-09-01

    Photo-transmutation of long-lived nuclear waste induced by a high-charge relativistic electron beam (e-beam) from a laser plasma accelerator is demonstrated. A collimated relativistic e-beam with a high charge of approximately 100 nC is produced from high-intensity laser interaction with near-critical-density (NCD) plasma. Such e-beam impinges on a high-Z convertor and then radiates energetic bremsstrahlung photons with flux approaching 1011 per laser shot. Taking a long-lived radionuclide 126Sn as an example, the resulting transmutation reaction yield is the order of 109 per laser shot, which is two orders of magnitude higher than obtained from previous studies. It is found that at lower densities, a tightly focused laser irradiating relatively longer NCD plasmas can effectively enhance the transmutation efficiency. Furthermore, the photo-transmutation is generalized by considering mixed-nuclide waste samples, which suggests that the laser-accelerated high-charge e-beam could be an efficient tool to transmute long-lived nuclear waste.

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

    International Nuclear Information System (INIS)

    Vasiljeva, I.V.; Mjakin, S.V.; Makarov, A.V.; Krasovsky, A.N.; Varlamov, A.V.

    2006-01-01

    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)

  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. Orbital angular momentum mode of Gaussian beam induced by atmospheric turbulence

    Science.gov (United States)

    Cheng, Mingjian; Guo, Lixin; Li, Jiangting; Yan, Xu; Dong, Kangjun

    2018-02-01

    Superposition theory of the spiral harmonics is employed to numerical study the transmission property of the orbital angular momentum (OAM) mode of Gaussian beam induced by atmospheric turbulence. Results show that Gauss beam does not carry OAM at the source, but various OAM modes appear after affected by atmospheric turbulence. With the increase of atmospheric turbulence strength, the smaller order OAM modes appear firstly, followed by larger order OAM modes. The beam spreading of Gauss beams in the atmosphere enhance with the increasing topological charge of the OAM modes caused by atmospheric turbulence. The mode probability density of the OAM generated by atmospheric turbulence decreases, and peak position gradually deviate from the Gauss beam spot center with the increase of the topological charge. Our results may be useful for improving the performance of long distance laser digital spiral imaging system.

  3. Photorefractive Axicon: Study of Light-induced Effect by Bessel Beam in Photorefractive Crystal

    International Nuclear Information System (INIS)

    Vieira, T A; Gesualdi, M R R; Zamboni-Rached, M; Muramatsu, M

    2011-01-01

    In this work, we present the theoretical and computational study of the original analysis of the light-induced effects by Bessel beams in photorefractive crystals. Modern applications of these beams as: metrological, alignment of optical systems, optical tweezers, non linear optics, optical communication, and others, becoming a very interesting substitute for a Gaussian beam when this is subject to diffraction and dispersion effects to large distance propagation. On the other hand, the photorefractive crystals are very important materials for applications in non-linear optics, holographic storage, interferometry and optical information processing. We perform an analysis of the index refraction modulation generated by Bessel beam in photorefractive medium discussing the possibility this optical material to control and generation of Bessel beam properties.

  4. Ultrafast Melting of Carbon Induced by Intense Proton Beams

    International Nuclear Information System (INIS)

    Pelka, A.; Guenther, M. M.; Harres, K.; Otten, A.; Roth, M.; Gregori, G.; Gericke, D. O.; Vorberger, J.; Glenzer, S. H.; Kritcher, A. L.; Heathcote, R.; Li, B.; Neely, D.; Kugland, N. L.; Niemann, C.; Makita, M.; Riley, D.; Mithen, J.; Schaumann, G.; Schollmeier, M.

    2010-01-01

    Laser-produced proton beams have been used to achieve ultrafast volumetric heating of carbon samples at solid density. The isochoric melting of carbon was probed by a scattering of x rays from a secondary laser-produced plasma. From the scattering signal, we have deduced the fraction of the material that was melted by the inhomogeneous heating. The results are compared to different theoretical approaches for the equation of state which suggests modifications from standard models.

  5. Beam diagnostics for Laser-induced proton generation at KAERI

    International Nuclear Information System (INIS)

    Kim, Dong Heun; Park, Seong Hee; Jeong, Young Uk; Lee, Ki Tae; Chan, Young Ho; Lee, Byung Cheol; Yoo, Byeong Duk

    2005-01-01

    With an advent of femto-second lasers, a laseraccelerated ion generation has been world-widely studied for medical and nuclear applications. It is known that protons with the energy from several tens MeV to a few hundreds MeV require for a cancer therapy and nuclear reaction. Even though, up to present, the maximum energy of laser-accelerated proton is about 60 MeV, it is expected that the energy of protons generated can be obtained at least up to 150 MeV. According to theoretical and experimental works, it turns out the energy distribution and the flux of ions strongly depends on the intensity of a fs laser at a target. However, physics on laser-plasma interaction is still not clear. The precise measurements of parameters of a fs laser and ions are important to figure out the physics and develop the theoretical interpretation. Typically, beam diagnostic system includes measurements and/or monitoring of the temporal and spatial profiles of lasers at the target as well as the energy spectrum and density profile of protons, which are critical for the analysis of mechanism and the characterization of protons generated. We fabricated and installed the target chamber for laser-accelerated proton generation and are now integrating beam diagnostic system. For laser diagnostics, beam monitoring and alignment system has been installed. For a charged particle, CR-39 detectors, Thomson parabola spectrometer, and Si charged particle detectors are installed for density profile and energy spectrum. In this paper, we discuss the laser beam monitoring and alignment system. We also estimates expected spectrum of protons from Thomson parabola spectrometer, depending on the parameters of protons

  6. Behavioral changes induced by single and multiple electron beam pulses

    International Nuclear Information System (INIS)

    Pease, V.P.; McNulty, P.J.

    1985-01-01

    The effects of single, and low-dose, high-dose-rate and multiple electron beam pulses on passive avoidance behavior in mice were studied. Passive avoidance was measured by recording the time that an animal took to enter a chamber from a narrow platform. There were four conditions in the experiment: (1) no shock no radiation-control, (2) radiation only, (3) shock only, and (4) radiation plus shock. Forty animals were run for each data point. Dose rate was held constant at 9 x 10/sup 7/ rads/sec. Average doses for the two single pulses were 7.18 and 8.72 rads. The average total dose for a 25 pulse per second condition was 324.0 rads. The differences between the single versus multiple pulse radiation-only conditions were significant with longer avoidance latencies in the multiple pulse condition. Avoidance latencies were also significantly longer in the shock plus radiation condition for the multiple beam pulse than the single pulse. It is concluded that single and multiple electron beam pulses significantly effect behavior, in this case producing avoidance

  7. Electrical Characterisation of electron beam exposure induced Defects in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Danga, Helga T., E-mail: helga.danga@up.ac.za; Auret, Francois D.; Coelho, Sergio M.M.; Diale, Mmantsae

    2016-01-01

    The defects introduced in epitaxially grown p-type silicon (Si) during electron beam exposure were electrically characterised using deep level transient spectroscopy (DLTS) and high resolution Laplace-DLTS. In this process, Si samples were first exposed to the conditions of electron beam deposition (EBD) without metal deposition. This is called electron beam exposure (EBE) herein. After 50 minutes of EBE, nickel (Ni) Schottky contacts were fabricated using the resistive deposition method. The defect level observed using the Ni contacts had an activation energy of H(0.55). This defect has an activation energy similar to that of the I-defect. The defect level is similar to that of the HB4, a boron related defect. DLTS depth profiling revealed that H(0.55) could be detected up to a depth of 0.8 μm below the junction. We found that exposing the samples to EBD conditions without metal deposition introduced a defect which was not introduced by the EBD method. We also observed that the damage caused by EBE extended deeper into the material compared to that caused by EBD.

  8. Cooperative effect of ultraviolet and near-infrared beams in laser-induced condensation

    Energy Technology Data Exchange (ETDEWEB)

    Matthews, M.; Henin, S.; Pomel, F.; Kasparian, J.; Wolf, J.-P. [Université de Genève, GAP-Biophotonics, Chemin de Pinchat 22, 1211 Geneva 4 (Switzerland); Théberge, F.; Daigle, J.-F. [Defence R and D Canada Valcartier, 2459 de la Bravoure Blvd., Quebec (Qc) G3J 1X5 (Canada); Lassonde, P.; Kieffer, J.-C. [INRS-EMT, 1650 Lionel Boulet Blvd., Varennes, Quebec (Qc) J3X1S2 (Canada)

    2013-12-23

    We demonstrate the cooperative effect of near infrared (NIR) and ultraviolet (UV) beams on laser-induced condensation. Launching a UV laser after a NIR pulse yields up to a 5-fold increase in the production of nanoparticles (25–300 nm) as compared to a single NIR beam. This cooperative effect exceeds the sum of those from the individual beams and occurs for delays up to 1 μs. We attribute it to the UV photolysis of ozone created by the NIR pulses. The resulting OH radicals oxidize NO{sub 2} and volatile organic compounds, producing condensable species.

  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. Beam energy spread in FERMI(at)elettra gun and linac induced by intrabeam scattering

    International Nuclear Information System (INIS)

    Zholents, Alexander A; Zholents, Alexander A; Zolotorev, Max S.; Penco, Giuseppe

    2008-01-01

    Intrabeam scattering (IBS) of electrons in the pre-cathode area in the electron guns know in the literature as Boersh effect is responsible for a growth of the electron beam energy spread there. Albeit most visible within the electron gun where the electron beam density is large and the energy spread is small, the IBS acts all along the entire electron beam pass through the Linac. In this report we calculate the energy spread induced by IBS in the FERMI(at)elettra electron gun

  11. 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.

  12. Effectiveness of trimethylopropane trimethacrylate for the electron-beam-irradiation-induced cross-linking of polylactic acid

    International Nuclear Information System (INIS)

    Ng, Hon-Meng; Bee, Soo-Tueen; Ratnam, C.T.; Sin, Lee Tin; Phang, Yee-Yao; Tee, Tiam-Ting; Rahmat, A.R.

    2014-01-01

    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

  13. Dose-response relationship for chromosomal aberrations induced in human lymphocytes by 18 MeV electron beam irradiation

    International Nuclear Information System (INIS)

    Lashin, E.A.; Elaasar, E.M.; Moustafa, H.F.; Bakir, Y.Y.; Al Zenki, S.D.

    1990-01-01

    Dose response curves for lymphocyte chromosome aberration frequencies using X- and gamma radiation became an important and reliable indicator as biological dosimeter especially in radiation accidents and occupational over exposures. Nowadays electron beam therapy is frequently used for their advantages in cases of tumours under or near to the body surface. Dose-response curves for these electron beams are rarely published. Human peripheral blood lymphocytes were in vitro irradiated with various low and high doses (0.1 Gy to 4.9 Gy) of 18 MeV electron beams to utilize such a dose-response curve using chromosomal aberration frequencies as a biological indicator. Then we compared the biological curve with physically obtained curves normally used in planning for radiotherapy treatment. It is interesting to find a significant difference between both of them. The biological curve is generally higher in value and the aberrations induced by 93% of a dose is significantly higher and deeper in site than those aberrations induced by the 100% dose calculated physically. If the above observation is confirmed by detailed studies, it would be of importance to the radiotherapist to plan for isodose curves according to biological determinations. (author)

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

    International Nuclear Information System (INIS)

    Olivero, P.; Manfredotti, C.; 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 quantitative study of the inhomogeneity of the charge transport parameter defined as the product of mobility and lifetime for both electron and holes. XBIL represents a technique complementary to ion beam induced luminescence (IBIL), which has already been used by our group, since X-ray energy loss profile in the material is different from that of MeV ions. X-ray induced luminescence maps have been performed simultaneously with induced photocurrent maps, to correlate charge transport and induced luminescence properties of diamond. Simultaneous XBICC and XBIL maps exhibit features of partial complementarity that have been interpreted on the basis of considerations on radiative and non-radiative recombination processes which compete with charge transport efficiency

  15. Decursin reduce radio-resistance of hypoxic regions under the proton beam therapy by induced HIF-1α degradation

    International Nuclear Information System (INIS)

    Jung, Myung Hwan; Kim, Kye Ryung

    2013-01-01

    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

  16. 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

  17. Electron-beam induced current characterization of back-surface field solar cells using a chopped scanning electron microscope beam

    Science.gov (United States)

    Luke, K. L.; Cheng, L.-J.

    1984-01-01

    A chopped electron beam induced current (EBIC) technique for the chacterization of back-surface field (BSF) solar cells is presented. It is shown that the effective recombination velocity of the low-high junction forming the back-surface field of BSF cells, in addition to the diffusion length and the surface recombination velocity of the surface perpendicular to both the p-n and low-high junctions, can be determined from the data provided by a single EBIC scan. The method for doing so is described and illustrated. Certain experimental considerations taken to enhance the quality of the EBIC data are also discussed.

  18. Prospects for measuring GMN in CLAS with higher CEBAF beam energies

    International Nuclear Information System (INIS)

    Brooks, W.

    1994-01-01

    The possibility exists for extending a planned measurement of the neutron magnetic form factor to higher values of momentum transfer. The theoretical interest and the experimental method are described. Problems associated with higher Q 2 measurements are discussed. It is concluded that measurements of moderate precision may be possible up to a Q 2 of 8-9.5 GeV 2 , more than doubling the range of the data currently available

  19. An effective method for detection and analysis of DNA damage induced by heavy-ion beams

    International Nuclear Information System (INIS)

    Kazama, Y.; Saito, H.; Fujiwara, M.; Matsuyama, T.; Hayashi, Y.; Ryuto, H.; Fukunishi, N.; Abe, T.

    2007-01-01

    We have developed an efficient system to detect and analyze DNA mutations induced by heavy-ion beams in Arabidopsis thaliana. In this system, a stable transgenic Arabidopsis line that constitutively expresses a yellow fluorescent protein (YFP) by a single-copy gene at a genomic locus was constructed and irradiated with heavy-ion beams. The YFP gene is a target of mutagenesis, and its loss of function or expression can easily be detected by the disappearance of YFP signals in planta under microscopy. With this system, a sup(12)Csup(6+)- induced mutant with single deletion and multiple base changes was isolated

  20. Development of a new light collection and detection system optimized for ion beam induced fluorescence microscopy

    International Nuclear Information System (INIS)

    Vanga, Sudheer Kumar; Mi, Zhaohong; Koh, Long Cheng; Tao, Ye; Bettiol, Andrew A.; Watt, Frank

    2015-01-01

    Ion beam induced fluorescence microscopy is a new imaging technique which has the potential to achieve sub-50 nm spatial resolution fluorescence images. Currently the resolution of the technique has been limited to around 150 nm mainly because of inefficient collection and detection of emitted photons from the sample. To overcome this limitation, a new light collection system based on a custom made parabolic mirror is employed to enhance the fluorescence collection. The custom made mirror is designed so as to obtain both structural (scanning transmission ion microscopy) and ion beam induced fluorescence imaging simultaneously. The design and characterization of the parabolic mirror is discussed in detail

  1. Soft-edged magnet models for higher-order beam-optics map codes

    International Nuclear Information System (INIS)

    Walstrom, P.L.

    2004-01-01

    Continuously varying surface and volume source-density distributions are used to model magnetic fields inside of cylindrical volumes. From these distributions, a package of subroutines computes on-axis generalized gradients and their derivatives at arbitrary points on the magnet axis for input to the numerical map-generating subroutines of the Lie-algebraic map code Marylie. In the present version of the package, the magnet menu includes: (1) cylindrical current-sheet or radially thick current distributions with either open boundaries or with a surrounding cylindrical boundary with normal field lines (which models high-permeability iron), (2) Halbach-type permanent multipole magnets, either as sheet magnets or as radially thick magnets, (3) modeling of arbitrary fields inside a cylinder by use of a fictitious current sheet. The subroutines provide on-axis gradients and their z derivatives to essentially arbitrary order, although in the present third- and fifth-order Marylie only the zeroth through sixth derivatives are needed. The formalism is especially useful in beam-optics applications, such as magnetic lenses, where realistic treatment of fringe-field effects is needed

  2. Status of higher order mode beam position monitors in 3.9 GHz superconducting accelerating cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M; Flisgen, T; Van Rienen, U; Shinton, I R R

    2013-01-01

    Higher order mode (HOM) beam position monitors (BPM) are being developed for the 3.9 GHz third harmonic superconducting accelerating cavities at FLASH. The transverse beam position in a cavity can be determined utilizing beam-excited HOMs based on dipole components. The existing couplers used for HOM suppression provide necessary signals. The diagnostics principle is similar to a cavity BPM, but requires no additional vacuum instruments on the linac. The challenges of HOM-BPM for 3.9 GHz cavities lie in the dense HOM spectrum arising from the coupling of the majority HOMs amongst the four cavities in the cryo-module ACC39. HOMs with particularly promising diagnostics features were evaluated using a spectrum analyzer and custom-built test electronics with various data analysis techniques, data reduction was focused on. After careful theoretical and experimental assessment of the HOM spectrum, multi-cavity modes in the region of 5 GHz were chosen to provide a global position over the complete module with superi...

  3. Ion beam induced epitaxy in Ge- and B- coimplanted silicon

    International Nuclear Information System (INIS)

    Hayashi, N.; Hasegawa, M.; Tanoue, H.; Takahashi, H.; Shimoyama, K.; Kuriyama, K.

    1992-01-01

    The epitaxial regrowth of amorphous surface layers in and Si substrate has been studied under irradiation with 400 keV Ar + ions at the temperature range from 300 to 435degC. The amorphous layers were obtained by Ge + implantation, followed by B + implantation. The ion beam assisted epitaxy was found to be sensitive to both the substrate orientation and the implanted Ge concentration, and the layer-by-layer epitaxial regrowth seemed to be precluded in Si layers with high doses of Ge implants, e.g., 2.5 x 10 15 ions/cm 2 . Electrical activation of implanted dopant B was also measured in the recrystallized Si layer. (author)

  4. Ion beam induced nanosized Ag metal clusters in glass

    International Nuclear Information System (INIS)

    Mahnke, H.-E.; Schattat, B.; Schubert-Bischoff, P.; Novakovic, N.

    2006-01-01

    Silver metal clusters have been formed in soda lime glass by high-energy heavy-ion irradiation at ISL. The metal cluster formation was detected with X-ray absorption spectroscopy (EXAFS) in fluorescence mode, and the shape of the clusters was imaged with transmission electron microscopy. While annealing in reducing atmosphere alone, leads to the formation of metal clusters in Ag-containing glasses, where the Ag was introduced by ion-exchange, such clusters are not very uniform in size and are randomly distributed over the Ag-containing glass volume. Irradiation with 600-MeV Au ions followed by annealing, however, results in clusters more uniform in size and arranged in chains parallel to the direction of the ion beam

  5. Chemically Induced Phase Transformation in Austenite by Focused Ion Beam

    Science.gov (United States)

    Basa, Adina; Thaulow, Christian; Barnoush, Afrooz

    2014-03-01

    A highly stable austenite phase in a super duplex stainless steel was subjected to a combination of different gallium ion doses at different acceleration voltages. It was shown that contrary to what is expected, an austenite to ferrite phase transformation occurred within the focused ion beam (FIB) milled regions. Chemical analysis of the FIB milled region proved that the gallium implantation preceded the FIB milling. High resolution electron backscatter diffraction analysis also showed that the phase transformation was not followed by the typical shear and plastic deformation expected from the martensitic transformation. On the basis of these observations, it was concluded that the change in the chemical composition of the austenite and the local increase in gallium, which is a ferrite stabilizer, results in the local selective transformation of austenite to ferrite.

  6. Measurement scheme of kicker impedances via beam-induced voltages of coaxial cables

    Energy Technology Data Exchange (ETDEWEB)

    Shobuda, Yoshihiro, E-mail: yoshihiro.shobuda@j-parc.jp [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Irie, Yoshiro [KEK, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Toyama, Takeshi; Kamiya, Junichiro [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Watanabe, Masao [Ministry of Education, Culture, Sports, Science and Technology, 3-2-2 Kasumigaseki, Chiyoda, Tokyo 100-8959 (Japan)

    2013-06-11

    A new theory, which satisfies the causality condition, is developed to describe impedances of kicker magnets with coaxial cables. The theoretical results well describe measurement results, which are obtained by standard wire methods. On the other hand, when beams pass through the kicker, voltages are induced at the terminals of coaxial cables. In other words, by analyzing the voltages, the kicker impedance for the beams can be obtained. The observed impedances are consistent with the theoretical results. The theory describes the impedance for non-relativistic beams, as well. The theoretical, simulation and measurement results indicate that the horizontal kicker impedance is drastically reduced by the non-relativistic effect. -- Highlights: ► We develop an innovative method to measure kicker impedance including power cable. ► By analyzing voltages at the ends of coaxial cables, the impedance is derived. ► The horizontal impedance is reduced as the beam becomes non-relativistic.

  7. 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.

  8. Electronic transitions in quantum dots and rings induced by inhomogeneous off-centered light beams.

    Science.gov (United States)

    Quinteiro, G F; Lucero, A O; Tamborenea, P I

    2010-12-22

    We theoretically investigate the effect of inhomogeneous light beams with (twisted light) and without (plane-wave light) orbital angular momentum on semiconductor-based nanostructures, when the symmetry axes of the beam and the nanostructure are displaced parallel to each other. Exact analytical results are obtained by expanding the off-centered light field in terms of the appropriate light modes centered around the nanostructure. We demonstrate how electronic transitions involving the transfer of different amounts of orbital angular momentum are switched on and off as a function of the separation between the axes of the beam and the system. In particular, we show that even off-centered plane-wave beams induce transitions such that the angular momenta of the initial and final states are different.

  9. 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

  10. Ion beam induced charge and cathodoluminescence imaging of response uniformity of CVD diamond radiation detectors

    CERN Document Server

    Sellin, P J; Galbiati, A; Maghrabi, M; Townsend, P D

    2002-01-01

    The uniformity of response of CVD diamond radiation detectors produced from high quality diamond film, with crystallite dimensions of >100 mu m, has been studied using ion beam induced charge imaging. A micron-resolution scanning alpha particle beam was used to produce maps of pulse height response across the device. The detectors were fabricated with a single-sided coplanar electrode geometry to maximise their sensitivity to the surface region of the diamond film where the diamond crystallites are highly ordered. High resolution ion beam induced charge images of single crystallites were acquired that demonstrate variations in intra-crystallite charge transport and the termination of charge transport at the crystallite boundaries. Cathodoluminescence imaging of the same crystallites shows an inverse correlation between the density of radiative centres and regions of good charge transport.

  11. Modeling of Low Frequency MHD Induced Beam Ion Transport In NSTX

    International Nuclear Information System (INIS)

    Gorelenkov, N.N.; Medley, S.S.

    2004-01-01

    Beam ion transport in the presence of low frequency MHD activity in National Spherical Tokamak Experiment (NSTX) plasma is modeled numerically and analyzed theoretically in order to understand basic underlying physical mechanisms responsible for the observed fast ion redistribution and losses. Numerical modeling of the beam ions flux into the NPA in NSTX shows that after the onset of low frequency MHD activity high energy part of beam ion distribution, E b > 40keV, is redistributed radially due to stochastic diffusion. Such diffusion is caused by high order harmonics of the transit frequency resonance overlap in the phase space. Large drift orbit radial width induces such high order resonances. Characteristic confinement time is deduced from the measured NPA energy spectrum and is typically ∼ 4msec. Considered MHD activity may induce losses on the order of 10% at the internal magnetic field perturbation (delta)B/B = Ο (10 -3 ), which is comparable to the prompt orbit losses

  12. Radioprotective efficacy of bisarylidene cyclopentanone on electron beam radiation induced oxidative stress in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Darshan Raj, C.G.; Sarojini, B.K.; Musthafa Khaleel, V.; Ramesh, S.R.; Ramakrishna, M.K.; Narayana, B.; Sanjeev, Ganesh

    2010-01-01

    Present study was carried out for evaluating the radioprotective effect of bischalcone (2E, 5E) - 2,5-bis (3-methoxy-4-hydroxy-benzylidene) cyclopentanone (curcumin analog (CA)), on electron beam radiation induced oxidative stress in Drosophila melanogaster adults. The oxidative stress markers and antioxidants included superoxide dismutase (SOD) and catalase (CAT). The oxidative stress was induced at 1.5 Gy. (author)

  13. 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

  14. Crosslinking of oriented polyethylene by electron beam radiation. Influence of morphology induced by drawing

    International Nuclear Information System (INIS)

    Aerle, N.A.J.M. van; Crevecoeur, G.; Lemstra, P.J.

    1988-01-01

    The influence of drawing on the crosslinking efficiency for electron beam radiation is reported for solution-crystallized ultra-high molecular weight polyethylene. A maximum in crosslinking efficiency is found at a draw ratio of approximately five, indicating an optimum morphology for inducing crosslinks during the hot-drawing process. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Huashun; Jiang, Jiasheng

    2017-02-21

    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.

  16. The rational design of a Au(I) precursor for focused electron beam induced deposition

    NARCIS (Netherlands)

    Marashdeh, Ali; Tiesma, Thiadrik; van Velzen, Niels J. C.; Harder, Sjoerd; Havenith, Remco W. A.; De Hosson, Jeff T. M.; van Dorp, Willem F.

    2017-01-01

    Au(I) complexes are studied as precursors for focused electron beam induced processing (FEBIP). FEBIP is an advanced direct-write technique for nanometer-scale chemical synthesis. The stability and volatility of the complexes are characterized to design an improved precursor for pure Au deposition.

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

    International Nuclear Information System (INIS)

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

    1984-10-01

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

  18. 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

  19. Towards high purity nanostructures from electron beam induced deposition of platinum

    NARCIS (Netherlands)

    Botman, A.P.J.M.

    2009-01-01

    Electron beam induced deposition (EBID) is a novel nanofabrication technique allowing the rapid prototyping of three-dimensional nanodevices and the metallic wiring of nanostructures, and is a promising technique for many applications in nanoresearch. EBID is a process wherein a precursor molecule

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

    DEFF Research Database (Denmark)

    van Dorp, Willem F; Lazic, Ivan; Beyer, André

    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 ...

  1. 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.

  2. Effect of solubility parameter of monomers on electron beam induced graft-polymerization onto polyethylene films

    International Nuclear Information System (INIS)

    Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

    1991-01-01

    Electron beam induced graft-polymerization by the mutual irradiation technique of monomers with different solubility parameters δ onto low density polyethylene films (LDPE) and high density polyethylene films (HDPE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic ratios of surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of monomers, and grafting rates onto LDPE were larger than those onto HDPE. Graft chain contents on surface, which were evaluated in terms of surface tensions and atomic ratios of the surface, increased with increasing δ of monomers, and graft chain contents on surface of HDPE were higher than those of LDPE. It is assumed that mutual solubility of PE and monomers, i.e., infiltration of monomers into PE during graft-polymerization influence grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

  3. Effect of solubility parameter of solvents on electron beam induced graft-polymerization onto polyethylene films

    International Nuclear Information System (INIS)

    Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

    1992-01-01

    Electron beam induced graft-polymerization by the mutual irradiation technique of methyl methacrylate (MMA) and methacrylic acid (MAAc) blended with solvents, which have different solubility parameters δ, onto high density polyethylene films (PE) were investigated at high dose rates (25 Mrad per second). Graft-polymerization mechanisms were discussed on the basis of grafting rates, surface tensions, atomic rations on the surface by XPS, and SEM images of the grafted films. Grafting rates decreased with increasing δ of solvents, and grafting rates for MMA were larger than those for MAAc. Graft chain contents on the surface, which were evaluated in terms of surface tensions and atomic ratios on the surface, increased with increasing δ of solvents, and graft chain contents on the surface of MAAc grafted PE were higher than those of MMA grafted PE. It is assumed that mutual solubility of PE and solvents (monomer solutions), i.e., infiltration of monomer solutions into PE during graft-polymerization, influenced grafting rates and graft sites in films. In case of high mutual solubility, grafting rates were large and graft sites spread from the surface into bulk. On the other hand, in case of low mutual solubility, grafting rates were small and graft sites localized on the surface of films. (author)

  4. Suspended tungsten-based nanowires with enhanced mechanical properties grown by focused ion beam induced deposition

    Science.gov (United States)

    Córdoba, Rosa; Lorenzoni, Matteo; Pablo-Navarro, Javier; Magén, César; Pérez-Murano, Francesc; María De Teresa, José

    2017-11-01

    The implementation of three-dimensional (3D) nano-objects as building blocks for the next generation of electro-mechanical, memory and sensing nano-devices is at the forefront of technology. The direct writing of functional 3D nanostructures is made feasible by using a method based on focused ion beam induced deposition (FIBID). We use this technique to grow horizontally suspended tungsten nanowires and then study their nano-mechanical properties by three-point bending method with atomic force microscopy. These measurements reveal that these nanowires exhibit a yield strength up to 12 times higher than that of the bulk tungsten, and near the theoretical value of 0.1 times the Young’s modulus (E). We find a size dependence of E that is adequately described by a core-shell model, which has been confirmed by transmission electron microscopy and compositional analysis at the nanoscale. Additionally, we show that experimental resonance frequencies of suspended nanowires (in the MHz range) are in good agreement with theoretical values. These extraordinary mechanical properties are key to designing electro-mechanically robust nanodevices based on FIBID tungsten nanowires.

  5. 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.

  6. Ion-beam-induced reactions in metal-thin-film-/BP system

    International Nuclear Information System (INIS)

    Kobayashi, N.; Kumashiro, Y.; Revesz, P.; Mayer, J.W.

    1989-01-01

    Ion-beam-induced reactions in Ni thin films on BP(100) have been investigated and compared with the results of the thermal reaction. The full reaction of Ni layer with BP induced by energetic heavy ion bombardments (600 keV Xe) was observed at 200degC and the formation of the crystalline phase corresponding to a composition of Ni 4 BP was observed. Amorphous layer with the same composition was formed by the bombardments below RT. For thermally annealed samples the reaction of the Ni layer on BP started at temperatures between 350degC and 400degC and full reaction was observed at 450degC. Metal-rich ternary phase or mixed binary phase is thought to be the first crystalline phase formed both in the ion-beam-induced and in the thermally induced reactions. The crystalline phase has the same composition and X-ray diffraction pattern both for ion-beam-induced and thermal reactions. Linear dependence of the reacted thickness on the ion fluence was also observed. The authors would like to express their sincere gratitude to Jian Li and Shi-Qing Wang for X-ray diffraction measurements at Cornell University. One of the authors (N.K.) acknowledge the Agency of Science and Technology of Japan for the financial support of his stay at Cornell. We also acknowledge Dr. H. Tanoue at ETL for his help in ion bombardment experiments. (author)

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

    International Nuclear Information System (INIS)

    Jung, Hyunkyu; Kim, Jongyeol; Lee, Namho; Kim, Youngwoong; Han, Wontaek; Markovic, Nikola; Jaksic, Milko

    2014-01-01

    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

  8. Proton beam characterization by proton-induced acoustic emission: simulation studies

    International Nuclear Information System (INIS)

    Jones, K C; Witztum, A; Avery, S; Sehgal, C M

    2014-01-01

    Due to their Bragg peak, proton beams are capable of delivering a targeted dose of radiation to a narrow volume, but range uncertainties currently limit their accuracy. One promising beam characterization technique, protoacoustic range verification, measures the acoustic emission generated by the proton beam. We simulated the pressure waves generated by proton radiation passing through water. We observed that the proton-induced acoustic signal consists of two peaks, labeled α and γ, with two originating sources. The α acoustic peak is generated by the pre-Bragg peak heated region whereas the source of the γ acoustic peak is the proton Bragg peak. The arrival time of the α and γ peaks at a transducer reveals the distance from the beam propagation axis and Bragg peak center, respectively. The maximum pressure is not observed directly above the Bragg peak due to interference of the acoustic signals. Range verification based on the arrival times is shown to be more effective than determining the Bragg peak position based on pressure amplitudes. The temporal width of the α and γ peaks are linearly proportional to the beam diameter and Bragg peak width, respectively. The temporal separation between compression and rarefaction peaks is proportional to the spill time width. The pressure wave expected from a spread out Bragg peak dose is characterized. The simulations also show that acoustic monitoring can verify the proton beam dose distribution and range by characterizing the Bragg peak position to within ∼1 mm. (paper)

  9. Electron beam exposure mechanisms in hydrogen silsesquioxane investigated by vibrational spectroscopy and in-situ electron beam induced desorption

    Energy Technology Data Exchange (ETDEWEB)

    Olynick, D.L.; Cord, B.; Schipotinin, A.; Ogletree, D.F.; Schuck, P.J.

    2009-11-13

    Hydrogen Silsesquioxane (HSQ) is used as a high-resolution resist with resolution down below 10nm half-pitch. This material or materials with related functionalities could have widespread impact in nanolithography and nanoscience applications if the exposure mechanism was understood and instabilities controlled. Here we have directly investigated the exposure mechanism using vibrational spectroscopy (both Raman and Fourier transform Infrared) and electron beam desorption spectrocscopy (EBDS). In the non-networked HSQ system, silicon atoms sit at the corners of a cubic structure. Each silicon is bonded to a hydrogen atom and bridges 3 oxygen atoms (formula: HSiO3/2). For the first time, we have shown, via changes in the Si-H2 peak at ~;;2200 cm -1 in the Raman spectra and the release of SiHx products in EBID, that electron-bam exposed materials crosslinks via a redistribution reaction. In addition, we observe the release of significantly more H2 than SiH2 during EBID, which is indicative of additional reaction mechanisms. Additionally, we compare the behavior of HSQ in response to both thermal and electron-beam induced reactions.

  10. Site control technique for quantum dots using electron beam induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Iizuka, Kanji; Jung, JaeHun; Yokota, Hiroshi [Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro, Minami-saitama, Saitama 3458501 (Japan)

    2014-05-15

    To develop simple and high throughput sit definition technique for quantum dots (QDs), the electron beam induced deposition (EBID) method was used as desorption guide of phosphorus atoms form InP substrate. As the results one or a few indium (In) droplets (DLs) were created in the carbon grid pattern by thermal annealing at a temperature of 450°C for 10 min in the ultra high vacuum condition. The size of In DLs was larger than QDs, but arsenide DLs by molecular beam in growth chamber emitted wavelength of 1.028μm at 50K by photoluminescence measurement.

  11. Site control technique for quantum dots using electron beam induced deposition

    International Nuclear Information System (INIS)

    Iizuka, Kanji; Jung, JaeHun; Yokota, Hiroshi

    2014-01-01

    To develop simple and high throughput sit definition technique for quantum dots (QDs), the electron beam induced deposition (EBID) method was used as desorption guide of phosphorus atoms form InP substrate. As the results one or a few indium (In) droplets (DLs) were created in the carbon grid pattern by thermal annealing at a temperature of 450°C for 10 min in the ultra high vacuum condition. The size of In DLs was larger than QDs, but arsenide DLs by molecular beam in growth chamber emitted wavelength of 1.028μm at 50K by photoluminescence measurement

  12. Setup for fission and evaporation cross-section measurements in reactions induced by secondary beams

    International Nuclear Information System (INIS)

    Hassan, A.A.; Luk'yanov, S.M.; Kalpakchieva, R.; Skobelev, N.K.; Penionzhkevich, Yu.Eh.; Dlouhy, 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 α-particle and fission fragment energy spectra. By measuring the α-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

  13. Multi-bunch energy spread induced by beam loading in standing wave structure

    International Nuclear Information System (INIS)

    Ferrario, M.; Tazzioli, F.

    1995-04-01

    The interaction of a relativistic beam with the modes of the TM 010 pass-band of a multicell cavity does not cause any problem: although all the modes are excited by the RF (radiofrequency) generator, resulting in different cell excitations during the cavity filling and the beam pulse, the net accelerating field exhibits negligible fluctuations from bunch to bunch. However, when the beam is not fully relativistic, this is no more true. The phase slippage occurring in the first cells, between the non relativistic beam and the lower pass-band modes, produces an effective enhancement of the shunt impedances, which is usually negligible for a relativistic beam in a well tuned cavity. Moreover, the voltage jumps (amplitude and phase) occurring at each bunch passage, as well as the beam detuning caused by the off-crest bunches, vary from cell to cell. These effects enhance dramatically the fluctuation of the accelerating voltage, with a dominant beating provided by the pass-band mode nearest to the pi-mode. The induced beam energy spread has been estimated by the help of two distinct codes, developed at Frascati (Italy) and (Saclay), with results in good agreement. While an interaction integral is computed at each bunch passage, the cavity refilling is calculated by solving coupled differential equations of the modes of the pass-band, driven by a generator linked to one end-cell. It is shown also that the intermode coupling arises from the external Q of the drive end-cell, and not from the wall losses. For illustration, the authors applied the method to the beam-loading problem in the SC capture cavity of the low charge injector of the TESLA test facility installed at DESY

  14. Investigations on ion-beam induced desorption from cryogenic surfaces; Untersuchungen zu ionenstrahlinduzierter Desorption von kryogenen Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Christoph

    2017-07-03

    A central component of FAIR, the Facility for Antiproton and Ion Research, will be the superconducting heavy ion synchrotron SIS100, which is supposed to provide reliable, high intensity beams for various applications. Its beam intensity is governed by the space charge limit, while the maximum energy is determined by the machine's magnetic rigidity. That means, ions with higher charge state can be accelerated to a higher energy, but with less intensity. For highest intensity beams, intermediate charge states have to be used instead of high charge state ions. This alleviates the issue of space charge but gives rise to dynamic vacuum effects, which also limit beam intensity: beam particles collide with residual gas particles, which leads to charge exchange and their subsequent loss. Impacting on the chamber wall, these ions release adsorbed gas particles. This process is called desorption and leads to a localized increase in pressure, which in turn causes more charge exchange. After a few rounds of self amplification, this can lead to total beam loss. This ''runaway-desorption'' is typically the main beam intensity limiting process for intermediate charge state (heavy) ion beams. The extent of this phenomenon is governed by two factors: the initial beam intensity and the desorption yield. The latter is examined within the scope of this thesis. Special emphasis is placed on the influence of the target's temperature, since the SIS100 will be a superconducting machine with cryogenic vacuum chamber walls. In order to investigate this topic, an experimental setup has been devised, built at the SIS18 and taken into commission. Based on the experience gained during operation, it has been continuously improved and extended. Another central innovation presented in this thesis is the use of gas dynamics simulations for an improved method of data analysis. Using this technique, environmental conditions like the chamber geometry and the connected

  15. Nonlinear propagation of a spatially incoherent laser beam: self-induced smoothing and reduction of scattering instabilities

    International Nuclear Information System (INIS)

    Maximov, A.V.; Ourdev, I.G.; Rozmus, W.; Capjack, C.E.; Mounaix, Ph.; Huller, S.; Pesme, D.; Tikhonchuk, V.T.; Divol, L.

    2000-01-01

    It is shown that plasma-induced angular spreading and spectral broadening of a spatially incoherent laser beam correspond to increased spatial and temporal incoherence of the laser light. The spatial incoherence is characterized by an effective beam f-number, decreasing in space along the direction of light propagation. Plasma-induced beam smoothing can influence laser-plasma interaction physics. In particular, decreasing the correlation time of the propagating laser light may dramatically reduce the levels of backward stimulated Brillouin and Raman scattering inside the plasma. Also, the decrease of the laser beam effective f-number reduces the reflectivity of backward stimulated Brillouin scattering. (authors)

  16. Threshold stoichiometry for beam induced nitrogen depletion of SiN

    International Nuclear Information System (INIS)

    Timmers, H.; Weijers, T.D.M.; Elliman, R.G.; Uribasterra, J.; Whitlow, H.J.; Sarwe, E.-L.

    2002-01-01

    Measurements of the stoichiometry of silicon nitride films as a function of the number of incident ions using heavy ion elastic recoil detection (ERD) show that beam-induced nitrogen depletion depends on the projectile species, the beam energy, and the initial stoichiometry. A threshold stoichiometry exists in the range 1.3>N/Si≥1, below which the films are stable against nitrogen depletion. Above this threshold, depletion is essentially linear with incident fluence. The depletion rate correlates non-linearly with the electronic energy loss of the projectile ion in the film. Sufficiently long exposure of nitrogen-rich films renders the mechanism, which prevents depletion of nitrogen-poor films, ineffective. Compromising depth-resolution, nitrogen depletion from SiN films during ERD analysis can be reduced significantly by using projectile beams with low atomic numbers

  17. Modeling of beam-induced damage of the LHC tertiary collimators

    Directory of Open Access Journals (Sweden)

    E. Quaranta

    2017-09-01

    Full Text Available Modern hadron machines with high beam intensity may suffer from material damage in the case of large beam losses and even beam-intercepting devices, such as collimators, can be harmed. A systematic method to evaluate thresholds of damage owing to the impact of high energy particles is therefore crucial for safe operation and for predicting possible limitations in the overall machine performance. For this, a three-step simulation approach is presented, based on tracking simulations followed by calculations of energy deposited in the impacted material and hydrodynamic simulations to predict the thermomechanical effect of the impact. This approach is applied to metallic collimators at the CERN Large Hadron Collider (LHC, which in standard operation intercept halo protons, but risk to be damaged in the case of extraction kicker malfunction. In particular, tertiary collimators protect the aperture bottlenecks, their settings constrain the reach in β^{*} and hence the achievable luminosity at the LHC experiments. Our calculated damage levels provide a very important input on how close to the beam these collimators can be operated without risk of damage. The results of this approach have been used already to push further the performance of the present machine. The risk of damage is even higher in the upgraded high-luminosity LHC with higher beam intensity, for which we quantify existing margins before equipment damage for the proposed baseline settings.

  18. Modeling of beam-induced damage of the LHC tertiary collimators

    Science.gov (United States)

    Quaranta, E.; Bertarelli, A.; Bruce, R.; Carra, F.; Cerutti, F.; Lechner, A.; Redaelli, S.; Skordis, E.; Gradassi, P.

    2017-09-01

    Modern hadron machines with high beam intensity may suffer from material damage in the case of large beam losses and even beam-intercepting devices, such as collimators, can be harmed. A systematic method to evaluate thresholds of damage owing to the impact of high energy particles is therefore crucial for safe operation and for predicting possible limitations in the overall machine performance. For this, a three-step simulation approach is presented, based on tracking simulations followed by calculations of energy deposited in the impacted material and hydrodynamic simulations to predict the thermomechanical effect of the impact. This approach is applied to metallic collimators at the CERN Large Hadron Collider (LHC), which in standard operation intercept halo protons, but risk to be damaged in the case of extraction kicker malfunction. In particular, tertiary collimators protect the aperture bottlenecks, their settings constrain the reach in β* and hence the achievable luminosity at the LHC experiments. Our calculated damage levels provide a very important input on how close to the beam these collimators can be operated without risk of damage. The results of this approach have been used already to push further the performance of the present machine. The risk of damage is even higher in the upgraded high-luminosity LHC with higher beam intensity, for which we quantify existing margins before equipment damage for the proposed baseline settings.

  19. Analysis of radiation pressure force exerted on a biological cell induced by high-order Bessel beams using Debye series

    International Nuclear Information System (INIS)

    Li, Renxian; Ren, Kuan Fang; Han, Xiang'e; Wu, Zhensen; Guo, Lixin; Gong, Shuxi

    2013-01-01

    Debye series expansion (DSE) is employed to the analysis of radiation pressure force (RPF) exerted on biological cells induced by high-order Bessel beams (BB). The beam shape coefficients (BSCs) for high-order Bessel beams are calculated using analytical expressions obtained by the integral localized approximation (ILA). Different types of cells, including a real Chinese Hamster Ovary (CHO) cell and a lymphocyte which are respectively modeled by a coated and five-layered sphere, are considered. The RPF induced by high-order Bessel beams is compared with that by Gaussian beams and zeroth-order Bessel beams, and the effect of different scattering processes on RPF is studied. Numerical calculations show that high-order Bessel beams with zero central intensity can also transversely trap particle in the beam center, and some scattering processes can provide longitudinal pulling force. -- Highlights: ► BSCs for high-order Bessel beam (HOBB) is derived using ILA. ► DSE is employed to study the RPF induced by HOBB exerted on multilayered cells. ► RPF is decided by radius relative to the interval of peaks in intensity profile. ► HOBB can also transversely trap high-index particle in the vicinity of beam axis. ► RPF for some scattering processes can longitudinally pull particles back

  20. 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.

  1. 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.

  2. Radioactive ion beams produced by neutron-induced fission at ISOLDE

    CERN Document Server

    Catherall, R; Gilardoni, S S; Köster, U

    2003-01-01

    The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

  3. Proteome Changes in Maize Embryo (Zea mays L) Induced by Ion Beam Implantation Treatment

    International Nuclear Information System (INIS)

    Li Yongliang; Qin Guangyong; Huo Yuping; Tian Shuangqi; Tang Jihua

    2009-01-01

    Low energy ion beam implantation was applied to the maize (Zea mays L) embryo proteome using two-dimensional gel electrophoresis. Protein profile analysis detected more than 1100 protein spots, 72 of which were determined to be expressed differently in the treated and control (not exposed to ion beam implantation) embryos. Of the 72 protein spots, 53 were up-regulated in the control and 19 were more abundantly expressed in the ion beam-treated embryos. The spots of up- or down-regulated proteins were identified by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Among the identified proteins, 11 were up-regulated in the treated embryos. Four of these up-regulated proteins were antioxidant molecules, three were related to stress response, two to sugar metabolism and two were associated with heat shock response. Of the five proteins up-regulated in the control embryos, three were functionally related to carbohydrate metabolism; the functions of the remaining two proteins were unknown. The data collected during this study indicate that treatment of maize embryos with low energy ion beam implantation induces changes in stress tolerance enzymes/proteins, possibly as a result of alterations in metabolism. (ion beam bioengineering)

  4. Decomposition of organic pollutants in industrial Effluent induced by advanced oxidation process with Electron beam irradiation

    International Nuclear Information System (INIS)

    Duarte, C.L.; Sampa, M.H.O.; Rela, P.R.; Oikawa, H.; Silveira, C.G.

    2001-01-01

    Advanced Oxidation Process (AOP) by electron beam irradiation induce the decomposition of pollutants in industrial effluent. Experiments were conducted using a Radiation Dynamics Electron Beam Accelerator with 1.5 MeV energy and 37 Kew power. Experiments were conducted using samples from a Governmental Wastewater Treatment Plant (WTP) that receives about 20% of industrial wastewater, with the objective of use the electrons beam technology to destroy the refractory organic pollutants. Samples from WTP main Industrial Receiver Unit influent (IRU), Coarse Bar Screens effluent (CBS), Medium Bar Screens effluent (MBS), Primary Sedimentation effluent (PS) and Final Effluent (FE), were collected and irradiated in the electron beam accelerator in a batch system. The delivered doses were 5.0kGy, 10.0kGy and 20.0kGy. The electron beam irradiation showed be efficient on destroying the organic compounds delivered in these effluents mainly chloroform, dichloroethane, methyl isobutyl ketone, benzene, toluene, xylene, phenol. The necessary dose to remove 90% of the most organic compounds from industry effluent was 20 kGy. The removal of organic compounds from this complex mixture were described by the destruction G value (Gd) that were obtained for those compounds in different initial concentration and compared with literature

  5. Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter.

    Science.gov (United States)

    Li, Peng; Han, Yu; Wang, Wenxin; Liu, Yanju; Jin, Peng; Leng, Jinsong

    2017-03-09

    Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a thermally induced optical beam-power splitter concept based on a shape memory polystyrene film with programmable micropatterns. The smooth film exhibits excellent transparency with a transmittance of 95% in the visible spectrum and optical stability during a continuous heating process up to 90 °C. By patterning double sided shape memory polystyrene film into erasable and switchable micro-groove gratings, the transmission light switches from one designed light divided directions and beam-power distribution to another because of the optical diffraction effect of the shape changing micro gratings during the whole thermal activated recovery process. The experimental and theoretical results demonstrate a proof-of-principle of the beam-power splitter. Our results can be adapted to further extend the applications of micro/nanophotonic devices and implement new features in the nanophotonics.

  6. HOM (higher-order mode) test of the storage ring single-cell cavity with a 20-MeV e- beam for the Advanced Photon Source (APS)

    International Nuclear Information System (INIS)

    Song, J.; Kang, Y.W.; Kustom, R.

    1993-01-01

    To test the effectiveness of damping techniques of the APS storage ring single-cell cavity, a beamline has been designed and assembled to use the ANL Chemistry Division linac beam (20-MeV, FWHM of 20 ps). A single-cell cavity will be excited by the electron beam to investigate the effect on higher-order modes (HOMs) with and without coaxial dampers (H-loop damper, E-probe damper), and wideband aperture dampers. In order for the beam to propagate on- and off-center of the cavity, the beamline consists of two sections -- a beam collimating section and a cavity measurement section -- separated by two double Aluminum foil windows. RF cavity measurements were made with coupling loops and E-probes. The results are compared with both the TBCI calculations and 'cold' measurements with the bead-perturbation method. The data acquisition system and beam diagnostics will be described in a separate paper

  7. Statistical methods for transverse beam position diagnostics with higher order modes in third harmonic 3.9 GHz superconducting accelerating cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei, E-mail: pei.zhang@desy.de [School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg (Germany); Cockcroft Institute of Science and Technology, Daresbury WA4 4AD (United Kingdom); Baboi, Nicoleta [Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, D-22607 Hamburg (Germany); Jones, Roger M. [School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Cockcroft Institute of Science and Technology, Daresbury WA4 4AD (United Kingdom)

    2014-01-11

    Beam-excited higher order modes (HOMs) can be used to provide beam diagnostics. Here we focus on 3.9 GHz superconducting accelerating cavities. In particular we study dipole mode excitation and its application to beam position determinations. In order to extract beam position information, linear regression can be used. Due to a large number of sampling points in the waveforms, statistical methods are used to effectively reduce the dimension of the system, such as singular value decomposition (SVD) and k-means clustering. These are compared with the direct linear regression (DLR) on the entire waveforms. A cross-validation technique is used to study the sample independent precisions of the position predictions given by these three methods. A RMS prediction error in the beam position of approximately 50 μm can be achieved by DLR and SVD, while k-means clustering suggests 70 μm.

  8. Statistical methods for transverse beam position diagnostics with higher order modes in third harmonic 3.9 GHz superconducting accelerating cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M

    2014-01-01

    Beam-excited higher order modes (HOM) can be used to provide beam diagnostics. Here we focus on 3.9 GHz superconducting accelerating cavities. In particular we study dipole mode excitation and its application to beam position determinations. In order to extract beam position information, linear regression can be used. Due to a large number of sampling points in the waveforms, statistical methods are used to effectively reduce the dimension of the system, such as singular value decomposition (SVD) and k-means clustering. These are compared with the direct linear regression (DLR) on the entire waveforms. A cross-validation technique is used to study the sample independent precisions of the position predictions given by these three methods. A RMS prediction error in the beam position of approximately 50 micron can be achieved by DLR and SVD, while k-means clustering suggests 70 micron.

  9. Beam-induced damage to the Tevatron components and what has been done about it

    International Nuclear Information System (INIS)

    Mokhov, N.V.; Czarapata, P.C.; Drozhdin, A.I.; Still, D.A.; Samulyak, R.V.

    2007-01-01

    A beam-induced damage to the Tevatron collimators happened in December 2003 was induced by a failure in the CDF Roman Pot detector positioning during the collider run. Possible scenarios of this failure resulted in an excessive halo generation and superconducting magnet quench have been studied via realistic simulations using the STRUCT and MARS14 codes. It is shown that the interaction of a misbehaved proton beam with the collimators result in a rapid local heating and a possible damage. A detailed consideration is given to the ablation process for the collimator material taking place in high vacuum. It is shown that ablation of tungsten (primary collimator) and stainless steel (secondary collimator) jaws results in creation of a groove in the jaw surface as was observed after the December's accident. The actions undertaken to avoid such an accident in future are described in detail. (author)

  10. Beam-induced damage to the Tevatron components and what has been done about it

    International Nuclear Information System (INIS)

    Mokhov, N.V.; Czarapata, P.C.; Drozhdin, A.I.; Still, D.A.; Samulyak, R.V.

    2006-01-01

    A beam-induced damage to the Tevatron collimators happened in December 2003 was induced by a failure in the CDF Roman Pot detector positioning during the collider run. Possible scenarios of this failure resulted in an excessive halo generation and superconducting magnet quench have been studied via realistic simulations using the STRUCT and MARS14 codes. It is shown that the interaction of a misbehaved proton beam with the collimators result in a rapid local heating and a possible damage. A detailed consideration is given to the ablation process for the collimator material taking place in high vacuum. It is shown that ablation of tungsten (primary collimator) and stainless steel (secondary collimator) jaws results in creation of a groove in the jaw surface as was observed after the December's accident. The actions undertaken to avoid such an accident in future are described in detail

  11. Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

    International Nuclear Information System (INIS)

    Lu Dong; Li Wenjian; Wu Xin; Wang Jufang; Ma Shuang; Liu Qingfang; He Jinyu; Jing Xigang; Ding Nan; Dai Zhongying; Zhou Jianping

    2010-01-01

    Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20 Ne 10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

  12. Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae

    Science.gov (United States)

    Lu, Dong; Li, Wenjian; Wu, Xin; Wang, Jufang; Ma, Shuang; Liu, Qingfang; He, Jinyu; Jing, Xigang; Ding, Nan; Dai, Zhongying; Zhou, Jianping

    2010-12-01

    Yeast strain Saccharomyces cerevisiae was irradiated with different doses of 85 MeV/u 20Ne10+ to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Gy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T→G and T→C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation.

  13. 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)

  14. LDPC coding for QKD at higher photon flux levels based on spatial entanglement of twin beams in PDC

    International Nuclear Information System (INIS)

    Daneshgaran, Fred; Mondin, Marina; Bari, Inam

    2014-01-01

    Twin beams generated by Parametric Down Conversion (PDC) exhibit quantum correlations that has been effectively used as a tool for many applications including calibration of single photon detectors. By now, detection of multi-mode spatial correlations is a mature field and in principle, only depends on the transmission and detection efficiency of the devices and the channel. In [2, 4, 5], the authors utilized their know-how on almost perfect selection of modes of pairwise correlated entangled beams and the optimization of the noise reduction to below the shot-noise level, for absolute calibration of Charge Coupled Device (CCD) cameras. The same basic principle is currently being considered by the same authors for possible use in Quantum Key Distribution (QKD) [3, 1]. The main advantage in such an approach would be the ability to work with much higher photon fluxes than that of a single photon regime that is theoretically required for discrete variable QKD applications (in practice, very weak laser pulses with mean photon count below one are used).The natural setup of quantization of CCD detection area and subsequent measurement of the correlation statistic needed to detect the presence of the eavesdropper Eve, leads to a QKD channel model that is a Discrete Memoryless Channel (DMC) with a number of inputs and outputs that can be more than two (i.e., the channel is a multi-level DMC). This paper investigates the use of Low Density Parity Check (LDPC) codes for information reconciliation on the effective parallel channels associated with the multi-level DMC. The performance of such codes are shown to be close to the theoretical limits.

  15. Electrical, structural, and bonding changes induced in silicon by H, Ar, and Kr ion-beam etching

    International Nuclear Information System (INIS)

    Singh, R.; Fonash, S.J.; Ashok, S.; Caplan, P.; Shappirio, J.; Hage-Ali, M.; Ponpon, J.

    1983-01-01

    A study to elucidate the role of processing-induced changes in Si, subjected to ion-beam etching has been made. It is shown that these changes can be related to the primary ion beam used in ion-beam etching. Using ESR, trivalently bonded Si has been shown to be present. Fe and Cr have been found to be the main contaminants. An annealing study revealed that the damage can be annealed out at relatively high temperatures

  16. A new route to nanoscale tomographic chemical analysis: Focused ion beam-induced auger electron spectrosocpy

    Science.gov (United States)

    Parvaneh, Hamed

    This research project is aimed to study the application of ion-induced Auger electron spectroscopy (IAES) in combination with the characteristics of focused ion beam (FIB) microscopy for performing chemical spectroscopy and further evaluate its potential for 3-dimensional chemical tomography applications. The mechanism for generation of Auger electrons by bombarding ions is very different from its electron induced counterpart. In the conventional electron-induced Auger electron spectroscopy (EAES), an electron beam with energy typically in the range 1-10kV is used to excite inner-shell (core) electrons of the solid. An electron from a higher electron energy state then de-excites to fill the hole and the extra energy is then transferred to either another electron, i.e. the Auger electron, or generation of an X-ray (photon). In both cases the emitting particles have charac-teristic energies and could be used to identify the excited target atoms. In IAES, however, large excitation cross sections can occur by promotion of in-ner shell electrons through crossing of molecular orbitals. Originally such phenomenological excitation processes were first proposed [3] for bi-particle gas phase collision systems to explain the generation of inner shell vacancies in violent collisions. In addition to excitation of incident or target atoms, due to a much heavier mass of ions compared to electrons, there would also be a substantial momentum transfer from the incident to the target atoms. This may cause the excited target atom to recoil from the lattice site or alternatively sputter off the surface with the possibility of de-excitation while the atom is either in motion in the matrix or traveling in vacuum. As a result, one could expect differences between the spectra induced by incident electrons and ions and interpretation of the IAE spectra requires separate consideration of both excitation and decay processes. In the first stage of the project, a state-of-the-art mass

  17. Beam-induced depolarisation at the HERMES transversely polarised hydrogen target

    International Nuclear Information System (INIS)

    Tait, P.

    2006-01-01

    This thesis describes the polarised hydrogen target of the HERMES experiment at DESY in Hamburg. The HERMES target is based on hyperfine-splitting of hydrogen in an external magnetic field and provides nuclear-polarised hydrogen for the HERMES experiment. Particular emphasis is placed on the phenomenon of beam-induced depolarisation. The HERA electron beam consists of short bunches which produce a high-frequency magnetic field. A Fourier analysis of these bunches leads to a series of harmonics, based on the fundamental frequency of roughly 10.4 MHz, which can cause a transition between hyperfine states of the target atoms. Only through careful setting of the external magnetic field is it possible to avoid these transitions and the resulting depolarisation of the target gas. Measurements of these resonances were made during the first HERMES run 1995-2000. The target region was modified in 2001 to allow HERMES to use hydrogen polarised perpendicularly to the direction of the electron beam. This modification gave HERMES access to the so-called 'Transversity' distribution for the first time, but also allows additional resonances in the target, which were previously forbidden by selection rules. The measurement and minimisation of these 'Sigma resonances' are presented. A distinctive feature of the HERMES experiment is its novel storage cell which allows target atoms to make multiple passes of the HERA beam. An exact description of beam-induced depolarisation must therefore consider the geometry of the storage cell and the distribution of the magnetic field throughout the cell. Calculations of the depolarisation can be made by solving the time-dependent Schroedinger equation using first-order perturbation theory. A simple analytical model and a molecular-flow Monte-Carlo are used to predict the exact shape of the resonances. The first measurements of the resonances with a transverse magnetic holding field are presented and compared with the simulations. (orig.)

  18. Electron beam instabilities in gyrotron beam tunnels

    International Nuclear Information System (INIS)

    Pedrozzi, M.; Alberti, S.; Hogge, J.P.; Tran, M.Q.; Tran, T.M.

    1997-10-01

    Electron beam instabilities occurring in a gyrotron electron beam can induce an energy spread which might significantly deteriorate the gyrotron efficiency. Three types of instabilities are considered to explain the important discrepancy found between the theoretical and experimental efficiency in the case of quasi-optical gyrotrons (QOG): the electron cyclotron maser instability, the Bernstein instability and the Langmuir instability. The low magnetic field gradient in drift tubes of QOG makes that the electron cyclotron maser instability can develop in the drift tube at very low electron beam currents. Experimental measurements show that with a proper choice of absorbing structures in the beam tunnel, this instability can be suppressed. At high beam currents, the electrostatic Bernstein instability can induce a significant energy spread at the entrance of the interaction region. The induced energy spread scales approximately linearly with the electron beam density and for QOG one observes that the beam density is significantly higher than the beam density of an equivalent cylindrical cavity gyrotron. (author) figs., tabs., refs

  19. Flux threshold measurements of He-ion beam induced nanofuzz formation on hot tungsten surfaces

    International Nuclear Information System (INIS)

    Meyer, F W; Hijazi, H; Bannister, M E; Unocic, K A; Garrison, L M; Parish, C M

    2016-01-01

    We report measurements of the energy dependence of flux thresholds and incubation fluences for He-ion induced nano-fuzz formation on hot tungsten surfaces at UHV conditions over a wide energy range using real-time sample imaging of tungsten target emissivity change to monitor the spatial extent of nano-fuzz growth, corroborated by ex situ SEM and FIB/SEM analysis, in conjunction with accurate ion-flux profile measurements. The measurements were carried out at the multicharged ion research facility (MIRF) at energies from 218 eV to 8.5 keV, using a high-flux deceleration module and beam flux monitor for optimizing the decel optics on the low energy MIRF beamline. The measurements suggest that nano-fuzz formation proceeds only if a critical rate of change of trapped He density in the W target is exceeded. To understand the energy dependence of the observed flux thresholds, the energy dependence of three contributing factors: ion reflection, ion range and target damage creation, were determined using the SRIM simulation code. The observed energy dependence can be well reproduced by the combined energy dependences of these three factors. The incubation fluences deduced from first visual appearance of surface emissivity change were (2–4) × 10 23 m −2 at 218 eV, and roughly a factor of 10 less at the higher energies, which were all at or above the displacement energy threshold. The role of trapping at C impurity sites is discussed. (paper)

  20. H2O2-induced higher order chromatin degradation: A novel ...

    Indian Academy of Sciences (India)

    Unknown

    mediator of oxidative stress, can also cause genomic damage indirectly. Thus, H2O2 at pathologically relevant concentrations rapidly induces higher order chromatin degradation (HOCD), i.e. enzymatic ... clease works through a single strand scission mechanism ... a great mutagenic risk to the surviving cells, because en-.

  1. 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.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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.

  3. Proteome Changes in Maize Embryo (Zea mays L) Induced by Ion Beam Implantation Treatment

    Science.gov (United States)

    Li, Yongliang; Tang, Jihua; Qin, Guangyong; Huo, Yuping; Tian, Shuangqi

    2009-08-01

    Low energy ion beam implantation was applied to the maize (Zea mays L) embryo proteome using two-dimensional gel electrophoresis. Protein profile analysis detected more than 1100 protein spots, 72 of which were determined to be expressed differently in the treated and control (not exposed to ion beam implantation) embryos. Of the 72 protein spots, 53 were up-regulated in the control and 19 were more abundantly expressed in the ion beam-treated embryos. The spots of up- or down-regulated proteins were identified by matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS). Among the identified proteins, 11 were up-regulated in the treated embryos. Four of these up-regulated proteins were antioxidant molecules, three were related to stress response, two to sugar metabolism and two were associated with heat shock response. Of the five proteins up-regulated in the control embryos, three were functionally related to carbohydrate metabolism; the functions of the remaining two proteins were unknown. The data collected during this study indicate that treatment of maize embryos with low energy ion beam implantation induces changes in stress tolerance enzymes/proteins, possibly as a result of alterations in metabolism.

  4. 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...

  5. A study of beam position diagnostics with beam-excited dipole higher order modes using a downconverter test electronics in third harmonic 3.9 GHz superconducting accelerating cavities at FLASH

    International Nuclear Information System (INIS)

    Zhang, P.; Baboi, N.; Lorbeer, B.; Wamsat, T.; Eddy, N.; Fellenz, B.; Wendt, M.; Jones, R.M.

    2012-08-01

    Beam-excited higher order modes (HOM) in accelerating cavities contain transverse beam position information. Previous studies have narrowed down three modal options for beam position diagnostics in the third harmonic 3.9 GHz cavities at FLASH. Localized modes in the beam pipes at approximately 4.1 GHz and in the fifth cavity dipole band at approximately 9 GHz were found, that can provide a local measurement of the beam position. In contrast, propagating modes in the first and second dipole bands between 4.2 and 5.5 GHz can reach a better resolution. All the options were assessed with a specially designed test electronics built by Fermilab. The aim is to de ne a mode or spectral region suitable for the HOM electronics. Two data analysis techniques are used and compared in extracting beam position information from the dipole HOMs: direct linear regression and singular value decomposition. Current experiments suggest a resolution of 50 m accuracy in predicting local beam position using modes in the fifth dipole band, and a global resolution of 20 m over the complete module. Based on these results we decided to build a HOM electronics for the second dipole band and the fifth dipole band, so that we will have both high resolution measurements for the whole module, and localized measurements for individual cavity. The prototype electronics is being built by Fermilab and planned to be tested in FLASH by the end of 2012.

  6. A study of beam position diagnostics with beam-excited dipole higher order modes using a downconverter test electronics in third harmonic 3.9 GHz superconducting accelerating cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, P. [Manchester Univ. (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Baboi, N.; Lorbeer, B.; Wamsat, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Eddy, N.; Fellenz, B.; Wendt, M. [Fermi National Accelerator Lab., Batavia, IL (United States); Jones, R.M. [Manchester Univ. (United Kingdom); The Cockcroft Institute, Daresbury (United Kingdom)

    2012-08-15

    Beam-excited higher order modes (HOM) in accelerating cavities contain transverse beam position information. Previous studies have narrowed down three modal options for beam position diagnostics in the third harmonic 3.9 GHz cavities at FLASH. Localized modes in the beam pipes at approximately 4.1 GHz and in the fifth cavity dipole band at approximately 9 GHz were found, that can provide a local measurement of the beam position. In contrast, propagating modes in the first and second dipole bands between 4.2 and 5.5 GHz can reach a better resolution. All the options were assessed with a specially designed test electronics built by Fermilab. The aim is to de ne a mode or spectral region suitable for the HOM electronics. Two data analysis techniques are used and compared in extracting beam position information from the dipole HOMs: direct linear regression and singular value decomposition. Current experiments suggest a resolution of 50 m accuracy in predicting local beam position using modes in the fifth dipole band, and a global resolution of 20 m over the complete module. Based on these results we decided to build a HOM electronics for the second dipole band and the fifth dipole band, so that we will have both high resolution measurements for the whole module, and localized measurements for individual cavity. The prototype electronics is being built by Fermilab and planned to be tested in FLASH by the end of 2012.

  7. Study of muon-induced neutron production using accelerator muon beam at CERN

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Y.; Lin, C. J.; Ochoa-Ricoux, J. P. [Lawrence Berkeley National Laboratory, Berkeley, California (United States); Draeger, E.; White, C. G. [Illinois Institute of Technology, Chicago, Illinois (United States); Luk, K. B.; Steiner, H. [Lawrence Berkeley National Laboratory, Berkeley, California (United States); Department of Physics, University of California, Berkeley, California (United States)

    2015-08-17

    Cosmogenic muon-induced neutrons are one of the most problematic backgrounds for various underground experiments for rare event searches. In order to accurately understand such backgrounds, experimental data with high-statistics and well-controlled systematics is essential. We performed a test experiment to measure muon-induced neutron production yield and energy spectrum using a high-energy accelerator muon beam at CERN. We successfully observed neutrons from 160 GeV/c muon interaction on lead, and measured kinetic energy distributions for various production angles. Works towards evaluation of absolute neutron production yield is underway. This work also demonstrates that the setup is feasible for a future large-scale experiment for more comprehensive study of muon-induced neutron production.

  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; 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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; 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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; 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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; 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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; Medina Hernandez, Carlos; 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 Thomas; 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; 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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; 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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

    2013-07-17

    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. 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.

  10. Pulsed ion-beam induced nucleation and growth of Ge nanocrystals on SiO2

    International Nuclear Information System (INIS)

    Stepina, N. P.; Dvurechenskii, A. V.; Armbrister, V. A.; Kesler, V. G.; Novikov, P. L.; Gutakovskii, A. K.; Kirienko, V. V.; Smagina, Zh. V.; Groetzschel, R.

    2007-01-01

    Pulsed low-energy (200 eV) ion-beam induced nucleation during Ge deposition on thin SiO 2 film was used to form dense homogeneous arrays of Ge nanocrystals. The ion-beam action is shown to stimulate the nucleation of Ge nanocrystals when being applied after thin Ge layer deposition. Temperature and flux variation was used to optimize the nanocrystal size and array density required for memory device. Kinetic Monte Carlo simulation shows that ion impacts open an additional channel of atom displacement from a nanocrystal onto SiO 2 surface. This results both in a decrease in the average nanocrystal size and in an increase in nanocrystal density

  11. Optimization of laser-plasma injector via beam loading effects using ionization-induced injection

    Science.gov (United States)

    Lee, P.; Maynard, G.; Audet, T. L.; Cros, B.; Lehe, R.; Vay, J.-L.

    2018-05-01

    Simulations of ionization-induced injection in a laser driven plasma wakefield show that high-quality electron injectors in the 50-200 MeV range can be achieved in a gas cell with a tailored density profile. Using the PIC code Warp with parameters close to existing experimental conditions, we show that the concentration of N2 in a hydrogen plasma with a tailored density profile is an efficient parameter to tune electron beam properties through the control of the interplay between beam loading effects and varying accelerating field in the density profile. For a given laser plasma configuration, with moderate normalized laser amplitude, a0=1.6 and maximum electron plasma density, ne 0=4 ×1018 cm-3 , the optimum concentration results in a robust configuration to generate electrons at 150 MeV with a rms energy spread of 4% and a spectral charge density of 1.8 pC /MeV .

  12. Electron Beam Induced Radiation Damage of the Semiconductor Radiation Detector based on Silicon

    International Nuclear Information System (INIS)

    Kim, Han Soo; Kim, Yong Kyun; Park, Se Hwan; Haa, Jang Ho; Kang, Sang Mook; Chung, Chong Eun; Cho, Seung Yeon; Park, Ji Hyun; Yoon, Tae Hyung

    2005-01-01

    A Silicon Surface Barrier (SSB) semiconductor detector which is generally used to detect a charged particle such as an alpha particle was developed. The performance of the developed SSB semiconductor detector was measured with an I-V curve and an alpha spectrum. The response for an alpha particle was measured by Pu-238 sources. A SSB semiconductor detector was irradiated firstly at 30sec, at 30μA and secondly 40sec, 40μA with a 2MeV pulsed electron beam generator in KAERI. And the electron beam induced radiation damage of a homemade SSB detector and the commercially available PIN photodiode were investigated. An annealing effect of the damaged SSB and PIN diode detector were also investigated using a Rapid Thermal Annealing (RTA). This data may assist in designing the silicon based semiconductor radiation detector when it is operated in a high radiation field such as space or a nuclear power plant

  13. Effect of storage conditions on graft of polypropylene non-woven fabric induced by electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Young; Jeun, Joon Pyo; Kang, Phil Hyun [Radiation Research Dvision for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup(Korea, Republic of)

    2015-05-15

    In this study, we fabricated effect of storage conditions on graft of polypropylene (PP) non-woven fabric induced by electron beam. The electron beam irradiations on PP non-woven fabric were carried out over a range of irradiation doses from 25 to 100 kGy to make free radicals on fabric surface. The radical measurement was established by electron spin resonance (ESR) for confirming the changes of the alkyl radical and peroxy radical according to effect of storage time, storage temperature and atmosphere. It was observed that the free radicals were increased with irradiation dose and decreased with storage time due to the continuous oxidation. However, the radical extinction was significantly delayed due to reduced mobility of radicals at extremely low temperature. The degree of graft based on the analysis of ESR was investigated. The conditions of graft reaction were set at a temperature: 60 degrees Celcius, reaction time: 6 hours and styrene monomer concentration: 20 wt%.

  14. Ferroelectric properties of Pb(Zr,Ti)O3 films under ion-beam induced strain

    Science.gov (United States)

    Lee, Jung-Kun; Nastasi, Michael

    2012-11-01

    The influence of an ion-beam induced biaxial stress on the ferroelectric and dielectric properties of Pb(Zr,Ti)O3 (PZT) films is investigated using the ion beam process as a novel approach to control external stress. Tensile stress is observed to decrease the polarization, permittivity, and ferroelectric fatigue resistance of the PZT films whose structure is monoclinic. However, a compressive stress increases all of them in monoclinic PZT films. The dependence of the permittivity on stress is found not to follow the phenomenological theory relating external forces to intrinsic properties of ferroelectric materials. Changes in the ferroelectric and dielectric properties indicate that the application of a biaxial stress modulates both extrinsic and intrinsic properties of PZT films. Different degrees of dielectric non-linearity suggests the density and mobility of non-180o domain walls, and the domain switching can be controlled by an applied biaxial stress and thereby influence the ferroelectric and dielectric properties.

  15. Electron-beam-irradiation-induced crystallization of amorphous solid phase change materials

    Science.gov (United States)

    Zhou, Dong; Wu, Liangcai; Wen, Lin; Ma, Liya; Zhang, Xingyao; Li, Yudong; Guo, Qi; Song, Zhitang

    2018-04-01

    The electron-beam-irradiation-induced crystallization of phase change materials in a nano sized area was studied by in situ transmission electron microscopy and selected area electron diffraction. Amorphous phase change materials changed to a polycrystalline state after being irradiated with a 200 kV electron beam for a long time. The results indicate that the crystallization temperature strongly depends on the difference in the heteronuclear bond enthalpy of the phase change materials. The selected area electron diffraction patterns reveal that Ge2Sb2Te5 is a nucleation-dominated material, when Si2Sb2Te3 and Ti0.5Sb2Te3 are growth-dominated materials.

  16. Xe ion beam induced rippled structures on differently oriented single-crystalline Si surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan [Forschungszentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, PO Box 510119, 01314 Dresden (Germany); Biermanns, Andreas; Pietsch, Ullrich, E-mail: A.Hanisch@fzd.d [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany)

    2010-03-24

    We report on Xe{sup +} induced ripple formation at medium energy on single-crystalline silicon surfaces of different orientations using substrates with an intentional miscut from the [0 0 1] direction and a [1 1 1] oriented wafer. The ion beam incidence angle with respect to the surface normal was kept fixed at 65{sup 0} and the ion beam projection was parallel or perpendicular to the [1 1 0] direction. By a combination of atomic force microscopy, x-ray diffraction and high-resolution transmission electron microscopy we found that the features of the surface and subsurface rippled structures such as ripple wavelength and amplitude and the degree of order do not depend on the surface orientation as assumed in recent models of pattern formation for semiconductor surfaces. (fast track communication)

  17. Analysis of art objects by means of ion beam induced luminescence

    International Nuclear Information System (INIS)

    Quaranta, A; Dran, J C; Salomon, J; Pivin, J C; Vomiero, A; Tonezzer, M; Maggioni, G; Carturan, S; Mea, G Della

    2006-01-01

    The impact of energetic ions on solid samples gives rise to the emission of visible light owing to the electronic excitation of intrinsic defects or extrinsic impurities. The intensity and position of the emission features provide information on the nature of the luminescence centers and on their chemical environments. This makes ion beam induced luminescence (IBIL) a useful complement to other ion beam analyses, like PIXE, in the cultural heritage field in characterizing the composition and the provenience of art objects. In the present paper, IBIL measurements have been performed on inorganic pigments for underlying the complementary role played by IBIL in the analysis of artistic works. Some blue and red pigment has been presented as case study

  18. A simulation study of electron-cloud instability and beam-induced multipacting in the LHC

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1997-02-01

    In the LHC beam pipe, photoemission and secondary emission give rise to a quasi-stationary electron cloud, which is established after a few bunch passages. The response of this electron cloud to a transversely displaced bunch resembles a short-range wakefield and can cause a fast instability. In addition, beam-induced multipacting of the electrons may lead to an enhanced gas desorption and an associated pressure increase. In this paper the authors report preliminary simulation results of the electron-cloud build-up both in a dipole magnet and in a straight section of the LHC at top energy. The effective wakefield created by the electron cloud translates into an instability rise time of about 25 ms horizontally and 130 ms vertically. This rise time is not much larger than that of the resistive-wall instability at injection energy

  19. DNA damage and chromosome aberration induced by heavy-ion beams

    International Nuclear Information System (INIS)

    Takakura, Kahoru; Funada, Aya; Aoki, Mizuho; Furusawa, Yoshiya

    2003-01-01

    The aim of this study is to clarify the relation between cell death and chromosomal aberration in cultured human cells (human salivary gland (HSG) tumor cells and GM05389 human normal fibroblasts) irradiated with heavy ion beams on the basis of linear energy transfer (LET) values. The LET dependences of cell death were observed for the both cells by the method of colony assay. The LET dependences of the chromosomal aberrations, breaks and gaps, isochromatid breaks and exchanges were also observed for the both cells using the premature chromosome condensation (PCC) method. From these results it is suggested that exchange formation is essential for the cell death caused by heavy ion beam irradiation. It is suspected that the densely ionizing track structure of hight LET heavy ions inhibits the effective repair in the chromatid breaks and isochromatid breaks and finally induce much exchange in the cells, which should be essential cause of cell death. (author)

  20. 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

  1. Improved single particle potential for transport model simulations of nuclear reactions induced by rare isotope beams

    International Nuclear Information System (INIS)

    Xu Chang; Li Baoan

    2010-01-01

    Taking into account more accurately the isospin dependence of nucleon-nucleon interactions in the in-medium many-body force term of the Gogny effective interaction, new expressions for the single-nucleon potential and the symmetry energy are derived. Effects of both the spin (isospin) and the density dependence of nuclear effective interactions on the symmetry potential and the symmetry energy are examined. It is shown that they both play a crucial role in determining the symmetry potential and the symmetry energy at suprasaturation densities. The improved single-nucleon potential will be useful for more accurate simulation of nuclear reactions induced by rare-isotope beams within transport models.

  2. Ion desorption induced by charged particle beams: mechanisms and mass spectroscopy

    International Nuclear Information System (INIS)

    Silveira, E.F. da; Schweikert, E.A.

    1988-01-01

    Surface analysis, through desorption, induced by fast particles, is presented and discussed. The stopping of projectils is essentially made by collisions with the target electrons. The desorbed particles are generally emmited with kinetic energy from 0.1 to 20 eV. Mass, charge, velocity and emission angle give information about the surface components, its structure as well as beam-solid interaction processes. Time-of-flight mass spectroscopy of desorbed ions, determine the mass of organic macromolecules and biomolecules. (A.C.A.S.) [pt

  3. Time-resolved ion beam induced charge collection (TRIBICC) in micro-electronics

    International Nuclear Information System (INIS)

    Schoene, H.; Walsh, D.S.; Sexton, F.W.; Doyle, B.L.; Aurand, J.F.; Dodd, P.E.; Flores, R.S.; Wing, N.

    1998-01-01

    The entire current transient induced by single 12 MeV Carbon ions was measured at a 5GHz analog bandwidth. A focused ion micro-beam was used to acquire multiple single ion transients at multiple locations of a single CMOS transistor. The current transients reveal clear and discernible contributions of drift and diffusive charge collection. Transients measured for drain and off-drain ion strikes compare well to 3D DAVINCI calculations. Estimates are presented for the drift assisted funneling charge collection depth

  4. Impurity mapping in sulphide minerals using Time-resolved Ion Beam Induced Current imaging

    International Nuclear Information System (INIS)

    Laird, Jamie S.; Johnson, Brett C.; Ganesan, Kumaravelu; Kandasamy, Sasikaran; Davidson, Garry; Borg, Stacey; Ryan, Chris G.

    2010-01-01

    The semiconducting properties and charge transport within natural minerals like pyrite are postulated to drive certain geochemical processes which can lead to precious metal ore genesis. In this paper we outline electrical measurements on mineral samples and present spatio-temporally resolved Ion Beam Induced Charge or Current studies on a Schottky pyrite junction. Au-Schottky contacts were fabricated in regions selected by thermoelectric and 4-point probe resistivity measurements. The complexity in charge transport due to impurity variations results in imaging contrast which is deemed important for fluid electrochemistry. The relevance of understanding charge collection in pyrite in the context of complex geochemical processes is briefly discussed.

  5. 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.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    The electron beam induced electronic transport in primary alkyl amine-intercalated V 2 O 5 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 demonstrate that the high conductivity of the nanotubes is related to the non-resonant tunnelling through the amine molecules and a reduced polaron hopping conduction through the vanadium oxide itself. Both nanotube networks and individual nanotubes exhibit similarly high conductivities where the minority carrier transport is bias dependent and nanotube diameter invariant. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Higher order mode spectra and the dependence of localized dipole modes on the transverse beam position in third harmonic superconducting cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei [Manchester Univ. (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Baboi, Nicoleta [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jones, Roger M. [The Cockcroft Institute, Daresbury (United Kingdom)

    2012-06-15

    An electron beam entering an accelerating cavity excites a wakefield. This wakefield can be decomposed into a series of multi-poles or modes. The dominant component of the transverse wakefield is dipole. This report summarizes the higher order mode (HOM) signals of the third harmonic cavities of FLASH measured at various stages: transmission measurements in the single cavity test stand at Fermilab, at CMTB (Cryo- Module Test Bench) and at FLASH, and beam-excited measurements at FLASH. Modes in the first two dipole bands and the fifth dipole band have been identified using a global Lorentzian fit technique. The beam-pipe modes at approximately 4 GHz and some modes in the fifth dipole band have been observed as localized modes, while the first two dipole bands, containing some strong coupling cavity modes, propagate. This report also presents the dependence of the localized dipole modes on the transverse beam position. Linear dependence for various modes has been observed. This makes them suitable for beam position diagnostics. These modes, together with some propagating, strong coupling modes, have been considered in the design of a dedicated electronics for beam diagnostics with HOMs for the third harmonic cavities.

  8. Honest signaling in trust interactions: smiles rated as genuine induce trust and signal higher earning opportunities

    OpenAIRE

    Centorrino, S.; Djemai, E.; Hopfensitz, A.; Milinski, M.; Seabright, P.

    2015-01-01

    We test the hypothesis that smiles perceived as honest serve as a signal that has evolved to induce cooperation in situations requiring mutual trust. Potential trustees (84 participants from Toulouse, France) made two video clips averaging around 15 seconds for viewing by potential senders before the latter decided whether to ‘send’ or ‘keep’ a lower stake (4 euros) or higher stake (8 euros). Senders (198 participants from Lyon, France) made trust decisions with respect to the recorded clips....

  9. The detection of electron-beam-induced current in junctionless semiconductor

    International Nuclear Information System (INIS)

    Tan, Chee Chin; Ong, Vincent K. S.

    2010-01-01

    The scanning electron microscope is a versatile tool and its electron beam techniques have been widely used in semiconductor material and device characterizations. One of these electron beam techniques is the electron-beam-induced current (EBIC) technique. One of the limitations of the conventional EBIC technique is that it requires charge collecting junctions which may not be readily available in junctionless samples such as bare substrates unless some special sample preparation procedure such as the fabrication of a diffused junction is done on the junctionless sample. In this paper, the technique of detecting EBIC current in junctionless samples with the use of a two-point probe is presented. It is found that the EBIC current is independent from its physical parameter when the sample thickness is greater than 4L; the width to the right of probe 2 and the width to the left of probe 1 are greater than 2L and 8L, respectively. The parameters affecting this technique of detecting the EBIC current such as the depth of the generation volume, probe spacing, and the applied bias are also discussed in this paper. A commercially available two-dimensional device simulator was used to verify this technique.

  10. Microstructural changes in silicon induced by patterning with focused ion beams of Ga, Si and Au

    International Nuclear Information System (INIS)

    Chee, See Wee; Kammler, Martin; Balasubramanian, Prabhu; Reuter, Mark C.; Hull, Robert; Ross, Frances M.

    2013-01-01

    We use focused beams of Ga + , Au + and Si ++ ions to induce local microstructural changes in single crystal silicon. The ions were delivered as single spot pulses into thin Si membranes that could subsequently be imaged and annealed in situ in a transmission electron microscope. For each ion, the focused ion beam implantation created an array of amorphous regions in the crystalline membrane. Annealing causes solid phase epitaxial regrowth to take place, but we show that the resulting microstructure depends on the ion species. For Ga + and Au + , precipitates remain after recrystallization, while for Si ++ , dislocation loops form around the periphery of each implanted spot. We attribute these loops to defects formed during solid phase epitaxial regrowth, with controlled placement of the loops possible. - Highlights: ► Ga + , Au + and Si ++ were implanted into thin membranes of Si. ► Samples were imaged and annealed in situ in a transmission electron microscope. ► Focused ion beam implantation created an array of amorphous spots. ► After recrystallization, precipitates form for Ga + and Au + , dislocation loops for Si ++ . ► Controlled placement of the dislocation loops possible

  11. Investigation of the extraction of short diffusion lengths from simulated electron-beam induced current

    Energy Technology Data Exchange (ETDEWEB)

    Wee, D.; Parish, G.; Nener, B. [Microelectronics Research Group, The University of Western Australia, 35 Stirling Highway, 6009 Crawley (Perth) (Australia)

    2010-10-15

    This paper reports on the investigations via 2-D simulation into the accuracy of diffusion length extraction from scanning electron-beam induced current measurements when the diffusion length, L is very short. L is extracted by using the direct method proposed by Chan et al.[1] and later refined by Kurniawan and Ong[2] to take finite junction depth into account. The 2-D simulations were undertaken using Synopsys {sup registered} Sentaurus TCAD and a realistic electron-hole pair generation volume was created using CASINO v2.42[3], a Monte Carlo Scanning Electron Microscope interaction simulation software, and imported into Sentaurus. The voltage and diameter of the electron beam and diffusion length and surface recombination velocity of the semiconductor materials were varied in the simulations to determine the errors in the diffusion length extracted from the EBIC signals as a function of these parameters. The results of the simulation show that the accuracy of the method proposed in[1] is reasonably accurate and that the beam voltage and spot size do not have significant effects on the accuracy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Investigation of the extraction of short diffusion lengths from simulated electron-beam induced current

    International Nuclear Information System (INIS)

    Wee, D.; Parish, G.; Nener, B.

    2010-01-01

    This paper reports on the investigations via 2-D simulation into the accuracy of diffusion length extraction from scanning electron-beam induced current measurements when the diffusion length, L is very short. L is extracted by using the direct method proposed by Chan et al.[1] and later refined by Kurniawan and Ong[2] to take finite junction depth into account. The 2-D simulations were undertaken using Synopsys registered Sentaurus TCAD and a realistic electron-hole pair generation volume was created using CASINO v2.42[3], a Monte Carlo Scanning Electron Microscope interaction simulation software, and imported into Sentaurus. The voltage and diameter of the electron beam and diffusion length and surface recombination velocity of the semiconductor materials were varied in the simulations to determine the errors in the diffusion length extracted from the EBIC signals as a function of these parameters. The results of the simulation show that the accuracy of the method proposed in[1] is reasonably accurate and that the beam voltage and spot size do not have significant effects on the accuracy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. High energy Xe{sup +} ion beam induced ripple structures on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hanisch, Antje; Grenzer, Joerg; Facsko, Stefan; Winkler, Ingolf [Forschungszentrum Dresden-Rossendorf, Institute for Ion Beam Physics and Materials Research, Dresden (Germany); Biermanns, Andreas; Grigorian, Souren; Pietsch, Ullrich [University of Siegen (Germany). Institute of Physics

    2008-07-01

    Ion beam bombardment on semiconductor surfaces leads to well-defined morphological structures in the nanoscale range. Due to the impact of ions a self-organized wave-like surface structure develops. Ion bombardment causes an amorphization of a surface-adjacent layer of several nanometers and creates a periodical structure on the surface as well as at the amorphous-crystalline interface. We investigate the dependence of the periodicity on the crystallography of (100) silicon bombarded with Xe{sup +} ions, the ion beam incidence and the azimutal angle of the sample surface. So far we found that the ripple wavelength scales with the ion energy in a range of 5 to 70 keV. In order to understand the initiation of the ripple formation we also ask the question which role the initial surface structure plays. Therefore we investigate the formation of ripples on pre-structured and rough surfaces such as wafers with an intentional miscut. Therefore, we not only introduce a certain initial roughness but also vary the orientation of the (100) lattice plane in respect to the surface. We distinguish between ion beam induced surface effects (sputter erosion) and the influence of the crystalline Si lattice (strain) on the ripple formation.

  14. Beam-induced heating / bunch length / RF and lessons for 2012

    International Nuclear Information System (INIS)

    Metral, E.

    2012-01-01

    Beam-induced heating has been observed here and there during the 2011 run when the bunch/beam intensity was increased and/or the bunch length was reduced. These observations are first reviewed before mentioning the recent news/work performed during the shutdown. In fact, several possible sources of heating exist and only the RF heating (i.e. coming from the real part of the longitudinal impedance of the machine components) is discussed in some detail in the present paper: 1) comparing the case of a Broad-Band (BB) vs. a Narrow-Band (NB) impedance; 2) discussing the beam spectrum; 3) reminding the usual solutions to avoid/minimize the RF heating; 4) reviewing the different heat transfer mechanisms; 5) mentioning that the synchronous phase shift is a measurement of the power loss and effective impedance. The three current 'hot' topics for the LHC performance, which are the VMTSA, TDI and MKI, are then analyzed in detail and some lessons for 2012 (and after) are finally drawn

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

    International Nuclear Information System (INIS)

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

    2009-01-01

    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 x 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.

  16. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    International Nuclear Information System (INIS)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-01-01

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm 2 and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO 2 lasers

  17. A System for Measuring Defect Induced Beam Modulation on Inertial Confinement Fusion-class Laser Optics

    Energy Technology Data Exchange (ETDEWEB)

    Runkel, M; Hawley-Fedder, R; Widmayer, C; Williams, W; Weinzapfel, C; Roberts, D

    2005-10-18

    A multi-wavelength laser based system has been constructed to measure defect induced beam modulation (diffraction) from ICF class laser optics. The Nd:YLF-based modulation measurement system (MMS) uses simple beam collimation and imaging to capture diffraction patterns from optical defects onto an 8-bit digital camera at 1053, 527 and 351 nm. The imaging system has a field of view of 4.5 x 2.8 mm{sup 2} and is capable of imaging any plane from 0 to 30 cm downstream from the defect. The system is calibrated using a 477 micron chromium dot on glass for which the downstream diffraction patterns were calculated numerically. Under nominal conditions the system can measure maximum peak modulations of approximately 7:1. An image division algorithm is used to calculate the peak modulation from the diffracted and empty field images after the baseline residual light background is subtracted from both. The peak modulation can then be plotted versus downstream position. The system includes a stage capable of holding optics up to 50 pounds with x and y translation of 40 cm and has been used to measure beam modulation due to solgel coating defects, surface digs on KDP crystals, lenslets in bulk fused silica and laser damage sites mitigated with CO{sub 2} lasers.

  18. Chemotherapy-Induced Fatigue Correlates With Higher Fatigue Scores Before Treatment.

    Science.gov (United States)

    Araújo, José Klerton Luz; Giglio, Adriana Del; Munhoz, Bruna Antenusse; Fonseca, Fernando Luiz Affonso; Cruz, Felipe Melo; Giglio, Auro Del

    2017-06-01

    Cancer chemotherapy can induce fatigue in about 20% to 30% of patients. So far, there is very little information as to the predictors of chemotherapy-induced fatigue (CIF). We evaluated potential predictors of CIF in a sample of patients with cancer with several types of solid tumors scheduled to receive chemotherapy according to institutional protocols. Before their first and second chemotherapy cycles, patients answered to the Brief Fatigue Inventory (BFI), Chalder, Mini Nutritional Assessment (MNA), Stress thermometer, and HADS questionnaires as well as provided blood samples for inflammatory markers. We evaluated 52 patients, 37 (71%) were female and mean age was 53 years. The most common tumors were breast cancer 21 (40%) and gastrointestinal tumors 12 (23%). Although 14 (25.2%) patients had an increase in their fatigue BFI scores equal or above 3 points from baseline, we observed no significant overall differences between BFI scores before and after chemotherapy. The only 2 factors associated with an increase of 3 points in the BFI scores after chemotherapy were race and higher baseline BFI levels. By multivariate analysis, overall BFI and Chalder scores after chemotherapy also correlated significantly with their respective baseline scores before treatment. HADS scores before treatment correlated with overall BFI scores postchemotherapy, whereas MNA scores before chemotherapy and female sex correlated with higher Chalder scores after treatment. We conclude that fatigue induced by chemotherapy is common and consistently associated with higher fatigue scores before treatment. Screening for fatigue before chemotherapy may help to identify patients who are prone to develop CIF.

  19. 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.

  20. Gain analysis of higher-order-mode amplification in a dielectric-implanted multi-beam traveling wave structure

    Energy Technology Data Exchange (ETDEWEB)

    Gee, Anthony; Shin, Young-Min

    2013-01-01

    A multi-beam traveling wave amplifier designed with an overmoded staggered double grating array was examined by small signal analysis combined with simulation. Eigenmode and S-parameter analyses show that the 2cm long slow wave structure (SWS) has 1-5dB insertion loss over the passband (TM31 mode) with ~28% cold bandwidth. Analytic gain calculation indicates that in the SWS, TM31-mode is amplified with 15–20 dB/beam at 64–84GHz with three elliptical beams of 10kV and 150mA/beam, which was compared with particle-in-cell (PIC) simulations. PIC analysis on the analysis of instability with zero-input driving excitations demonstrated that background noises and non-operating lower order modes are noticeably suppressed by implanting equidistant dielectric absorbers; the overmoded structure only allowed the desired 3rd order mode to propagate in the structure. The designed circuit structure can be widely applied to multi-beam devices for high power RF generation.

  1. Gain analysis of higher-order-mode amplification in a dielectric-implanted multi-beam traveling wave structure

    International Nuclear Information System (INIS)

    Gee, Anthony; Shin, Young-Min

    2013-01-01

    A multi-beam traveling wave amplifier designed with an overmoded staggered double grating array was examined by small signal analysis combined with simulation. Eigenmode and S-parameter analyses show that the 2 cm long slow wave structure (SWS) has 1–5 dB insertion loss over the passband (TM 31 mode) with ∼28% cold bandwidth. Analytic gain calculation indicates that in the SWS, TM 31 -mode is amplified with 15–20 dB/beam at 64–84 GHz with three elliptical beams of 10 kV and 150 mA/beam, which was compared with particle-in-cell (PIC) simulations. PIC analysis on the analysis of instability with zero-input driving excitations demonstrated that background noises and non-operating lower order modes are noticeably suppressed by implanting equidistant dielectric absorbers; the overmoded structure only allowed the desired 3rd order mode to propagate in the structure. The designed circuit structure can be widely applied to multi-beam devices for high power RF generation

  2. Study of the thermal effect on silicon surface induced by ion beam from plasma focus device

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Z., E-mail: pscientific5@aec.org.sy [Scientific Service Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Ahmad, M. [IBA Laboratory, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Chemistry Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic); Al-Hawat, Sh.; Akel, M. [Physics Department, Atomic Energy Commission of Syria, P.O. Box: 6091, Damascus (Syrian Arab Republic)

    2017-04-01

    Structural modifications in form of ripples and cracks are induced by nitrogen ions from plasma focus on silicon surface. The investigation of such structures reveals correlation between ripples and cracks formation in peripheral region of the melt spot. The reason of such correlation and structure formation is explained as result of thermal effect. Melting and resolidification of the center of irradiated area occur within one micro second of time. This is supported by a numerical simulation used to investigate the thermal effect induced by the plasma focus ion beams on the silicon surface. This simulation provides information about the temperature profile as well as the dynamic of the thermal propagation in depth and lateral directions. In accordance with the experimental observations, that ripples are formed in latter stage after the arrival of last ion, the simulation shows that the thermal relaxation takes place in few microseconds after the end of the ion beam arrival. Additionally, the dependency of thermal propagation and relaxation on the distance of the silicon surface from the anode is presented.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    Agostino Marinelli

    2010-11-01

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

  5. Nonlinear thermally induced distortions of a laser beam in a cryogenic disk amplifier

    International Nuclear Information System (INIS)

    Vyatkin, A G; Khazanov, Efim A

    2009-01-01

    Taking into account the temperature dependences of the heat conductivity, the refractive index, and the thermal expansion coefficient, we calculated the temperature, elastic stresses, a thermally induced lens and depolarisation of a beam in a cryogenic disk amplifier (an Yb:YAG disk placed between a copper cylinder and a sapphire disk cooled by liquid nitrogen). When the active element (the thickness is 0.6 mm, the orientation is [001], the atomic concentration of Yb is 10%) is pumped by radiation from a diode laser (the beam diameter is 6 mm), the temperature does not exceed 140 K for the heat release power of 100 W. In this case, elastic stresses in the active element are six times lower than the maximum permissible value. The focal distance of the thermally induced lens is 5.5 m and the depolarisation rate is 0.038% per two passes through the active element. Although the heat conductivity of the active element rapidly decreases with temperature, the thermal load can be increased by 1.5-2 times when the dimensions of the active element remain constant. (active media)

  6. Nature of gallium focused ion beam induced phase transformation in 316L austenitic stainless steel

    International Nuclear Information System (INIS)

    Babu, R. Prasath; Irukuvarghula, S.; Harte, A.; Preuss, M.

    2016-01-01

    The microstructural evolution and chemistry of the ferrite phase (α), which transforms from the parent austenite phase (γ) of 316L stainless steel during gallium (Ga) ion beam implantation in Focused Ion Beam (FIB) instrument was systematically studied as a function of Ga"+ ion dose and γ grain orientations. The propensity for initiation of γ → α phase transformation was observed to be strongly dependent on the orientation of the γ grain with respect to the ion beam direction and correlates well with the ion channelling differences in the γ orientations studied. Several α variants formed within a single γ orientation and the sputtering rate of the material, after the γ → α transformation, is governed by the orientation of α variants. With increased ion dose, there is an evolution of orientation of the α variants towards a variant of higher Ga"+ channelling. Unique topographical features were observed within each specific γ orientation that can be attributed to the orientation of defects formed during the ion implantation. In most cases, γ and α were related by either Kurdjumov-Sachs (KS) or Nishiyama-Wassermann (NW) orientation relationship (OR) while in few, no known OR's were identified. While our results are consistent with gallium enrichment being the cause for the γ → α phase transformation, some observations also suggest that the strain associated with the presence of gallium atoms in the lattice has a far field stress effect that promotes the phase transformation ahead of gallium penetration.

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

    International Nuclear Information System (INIS)

    Camacho-Lopez, Santiago; Evans, Rodger; Escobar-Alarcon, Luis; Camacho-Lopez, Miguel A.; Camacho-Lopez, Marco A.

    2008-01-01

    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 2 in the well-known Rutile phase. The laser irradiated areas on the film acquired selective (upon recording polarization) holographic reflectance

  8. 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.

  9. 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.

  10. Radiation-induced decomposition and enzymatic hydrolysis of cellulose. [Electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Kumakura, M; Kaetsu, I

    1978-08-01

    Preirradiation as a means for solubilization of cellulosic raw materials, such as rice straw, wheat straw, chaff, and sawdust, with subsequent cellulase treatment was investigated. The results showed that electron beam irradiation caused a slow increase in the reducing sugar formation with increasing dose above 1 x 10/sup 8/ R. It then increased more rapidly in the dose range between 1 x 10/sup 8/ and 5 x 10/sup 8/ R. Reducing sugar formation in samples irradiated after fine mechanical crushing was higher than that in samples crushed after irradiation. (JSR)

  11. Assessment of electron beam-induced abnormal development and DNA damage in Spodoptera litura (F.) (Lepidoptera: Noctuidae)

    International Nuclear Information System (INIS)

    Yun, Seung- Hwan; Lee, Seon-Woo; Koo, Hyun-Na; Kim, Gil- Hah

    2014-01-01

    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. - Highlights: • Electron beam irradiation induced abnormal development of the cutworm. • Electron beam irradiation induced the sterility of the cutworm. • Electron beam irradiation increased levels of DNA damage. • DNA damage by high irradiation exposure was not completely repaired

  12. Cell killing and chromosomal aberration induced by heavy-ion beams in cultured human tumor cells

    International Nuclear Information System (INIS)

    Takakura, K.; Funada, A.; Mohri, M.; Lee, R.; Aoki, M.; Furusawa, Y.; Gotoh, E.

    2003-01-01

    Full text: To clarify the relation between cell death and chromosomal aberration in cultured human tumor cells irradaited with heavy-ion beams. The analyses were carried out on the basis of the linear energy transfer (LET) values of heavy ion beams as radiation source. Exponentially growing human tumor cells, Human Salivary Gland Tumor cells (HSG cells), were irradiated with various high energy heavy ions, such as 13 keV/micrometer carbon (C) ions as low LET charged particle radiation source, 120 keV/ micrometer carbon (C) ions and 440 keV/micrometer iron (Fe) ions as high LET charged particle radiation sources.The cell death was analysed by the colony formation method, and the chromosomal aberration and its repairing kinetics was analysed by prematurely chromosome condensation method (PCC method) using calyculin A. Chromatid-type breaks, isochromatid breaks and exchanges were scored for the samples from the cells keeping with various incubation time after irradiation. The LET dependence of the cell death was similar to that of the chromosome exchange formation after 12 hours incubation. A maximum peak was around 120 keV/micrometer. However it was not similar to the LET dependence of isochromatid breaks or chromatid breaks after 12 hours incubation. These results suggest that the exchanges formed in chromosome after irradiation should be one of essential causes to lead the cell death. The different quality of induced chromosome damage between high-LET and low-LET radiation was also shown. About 89 % and 88 % chromatid breaks induced by X rays and 13 keV/micrometer C ions were rejoined within 12 hours of post-irradiation, though only 71% and 58 % of chromatid breaks induced by 120 keV/micrometer C ions and 440 keV/micrometer Fe ions were rejoined within 12 hours of post-irradiation

  13. Abaca/polyester nonwoven fabric functionalization for metal ion adsorbent synthesis via electron beam-induced emulsion grafting

    International Nuclear Information System (INIS)

    Madrid, Jordan F.; Ueki, Yuji; Seko, Noriaki

    2013-01-01

    A metal ion adsorbent was developed from a nonwoven fabric trunk material composed of both natural and synthetic polymers. A pre-irradiation technique was used for emulsion grafting of glycidyl methacrylate (GMA) onto an electron beam irradiated abaca/polyester nonwoven fabric (APNWF). The dependence of degree of grafting (Dg), calculated from the weight of APNWF before and after grafting, on absorbed dose, reaction time and monomer concentration were evaluated. After 50 kGy irradiation with 2 MeV electron beam and subsequent 3 h reaction with an emulsion consisting of 5% GMA and 0.5% polyoxyethylene sorbitan monolaurate (Tween 20) surfactant in deionized water at 40 °C, a grafted APNWF with a Dg greater than 150% was obtained. The GMA-grafted APNWF was further modified by reaction with ethylenediamine (EDA) in isopropyl alcohol at 60 °C to introduce amine functional groups. After a 3 h reaction with 50% EDA, an amine group density of 2.7 mmole/gram adsorbent was achieved based from elemental analysis. Batch adsorption experiments were performed using Cu 2+ and Ni 2+ ions in aqueous solutions with initial pH of 5 at 30 °C. Results show that the adsorption capacity of the grafted adsorbent for Cu 2+ is four times higher than Ni 2+ ions. - Highlights: • An amine type adsorbent from abaca/polyester nonwoven fabric was synthesized. • Pre-irradiation method was used in grafting glycidyl methacrylate on nonwoven fabric. • Radiation-induced grafting was performed with monomer in emulsion state. • The calculated adsorption capacity for Cu 2+ is four times higher than Ni 2+ ions. • Grafted adsorbent can remove Cu 2+ faster than a chemically similar commercial resin

  14. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    International Nuclear Information System (INIS)

    Wang Jufang; Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian

    2010-01-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1 ) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1 . The mutation cross section saturated when LET was higher than 58.2 keV μm -1 . Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1 . The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  15. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Science.gov (United States)

    Wang, Jufang; Lu, Dong; Wu, Xin; Sun, Haining; Ma, Shuang; Li, Renmin; Li, Wenjian

    2010-09-01

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV μm -1) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV μm -1. The mutation cross section saturated when LET was higher than 58.2 keV μm -1. Meanwhile, the highest RBE i for inactivation located at 120.0 keV μm -1 and the highest RBE m for mutation was at 58.2 keV μm -1. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  16. Inactive and mutagenic effects induced by carbon beams of different LET values in a red yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jufang, E-mail: jufangwang@impcas.ac.c [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China); Lu Dong; Wu Xin; Sun Haining; Ma Shuang; Li Renmin; Li Wenjian [Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road No. 509, Lanzhou 730000 (China)

    2010-09-15

    To evaluate biological action of microorganism exposed to charged particles during the long distance space exploration, induction of inactivation and mutation in a red yeast strain Rhodotorula glutinis AY 91015 by carbon beams of different LET values (14.9-120.0 keV {mu}m{sup -1}) was investigated. It was found that survival curves were exponential, and mutation curves were linear for all LET values. The dependence of inactivation cross section on LET approached saturation near 120.0 keV {mu}m{sup -1}. The mutation cross section saturated when LET was higher than 58.2 keV {mu}m{sup -1}. Meanwhile, the highest RBE{sub i} for inactivation located at 120.0 keV {mu}m{sup -1} and the highest RBE{sub m} for mutation was at 58.2 keV {mu}m{sup -1}. The experiments imply that the most efficient mutagenic part of the depth dose profile of carbon ion is at the plateau region with intermediate LET value in which energy deposited is high enough to induce mutagenic lesions but too low to induce over kill effect in the yeast cells.

  17. Spontaneous and stimulated emission induced by an electron, electron bunch, and electron beam in a plasma

    International Nuclear Information System (INIS)

    Kuzelev, M V; Rukhadze, A A

    2008-01-01

    Two fundamental mechanisms - the Cherenkov effect and anomalous Doppler effect - underlying the emission by an electron during its superluminal motion in medium are considered. Cherenkov emission induced by a single electron and a small electron bunch is spontaneous. In the course of spontaneous Cherenkov emission, the translational motion of an electron is slowed down and the radiation energy grows linearly with time. As the number of radiating electrons increases, Cherenkov emission becomes stimulated. Stimulated Cherenkov emission represents a resonance beam instability. This emission process is accompanied by longitudinal electron bunching in the beam or by the breaking of an electron bunch into smaller bunches, in which case the radiation energy grows exponentially with time. In terms of the longitudinal size L e of the electron bunch there is a transition region λ e 0 -1 between the spontaneous and stimulated Cherenkov effects, where λ is the average radiation wavelength, and δ 0 is the dimensionless (in units of the radiation frequency) growth rate of the Cherenkov beam instability. The range to the left of this region is dominated by spontaneous emission, whereas the range to the right of this region is dominated by stimulated emission. In contrast to the Vavilov-Cherenkov effect, the anomalous Doppler effect should always (even for a single electron) be considered as stimulated, because it can only be explained by accounting for the reverse action of the radiation field on the moving electron. During stimulated emission in conditions where anomalous Doppler effect shows itself, an electron is slowed down and spins up; in this case, the radiation energy grows exponentially with time. (reviews of topical problems)

  18. 6 MeV pulsed electron beam induced surface and structural changes in polyimide

    Energy Technology Data Exchange (ETDEWEB)

    Mathakari, Narendra L.; Bhoraskar, Vasant N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Dhole, Sanjay D., E-mail: sanjay@physics.unipune.ernet.i [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India)

    2010-04-15

    Thin films of polyimide (PMDA-ODA, Kapton) having 50 mum thickness were irradiated with 6 MeV pulsed electron beam. The bulk and surface properties of pristine and irradiated samples were characterized by several techniques such as stress-strain measurements, Fourier Transform Infrared (FTIR), UV-vis spectroscopy, contact angle, atomic force microscopy (AFM) and profilometry. The tensile strength, percentage elongation and strain energy show an enhancement from pristine value of 73-89 MPa, 10-22% and 4.75-14.2 MJ/m{sup 3} respectively at the maximum fluence of 4 x 10{sup 15} electrons/cm{sup 2}. This signifies that polyimide being an excessively aromatic polymer is crosslinked due to high-energy electron irradiation. In surface properties, the contact angle shows a significant decrease from 59 deg. to 32 deg. indicating enhancement in hydrophilicity. This mainly attributes to surface roughening, which is due to the electron beam induced sputtering. The surface roughening is confirmed in AFM and profilometry measurements. The AFM images clearly show that surface roughness increases after electron irradiation. Moreover, the roughness average (R{sub a}) as measured from surface profilograms is found to increase from 0.06 to 0.1. The FTIR and UV-vis spectra do not show noticeable changes as regards to scissioning of bonds and the oxidation. This work leads to a definite conclusion that 6 MeV pulsed electron beam can be used to bring about desired changes in surface as well as bulk properties of polyimide, which is considered to be a high performance space quality polymer.

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

    International Nuclear Information System (INIS)

    Fedorov, Andrei G.; Kim, Songkil; Henry, Mathias; Kulkarni, Dhaval; Tsukruk, Vladimir V.

    2014-01-01

    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. Electron beam-induced Fries rearrangement of arylsulfonamides and arylsulfonates in the crystalline state

    International Nuclear Information System (INIS)

    Kato, Jun; Yuasa, Kanako; Yamashita, Takashi; Maekawa, Yasunari; Yoshida, Masaru

    2003-01-01

    Electron beam (EB)-induced reactions of organic crystals containing a carbonyl or a sulfonyl group have been investigated. The EB irradiation of benzenesulfonanilide (BSA) in the crystalline state induced the Fries rearrangement to yield o- and p-aminodiphenylsulfones as the major and minor products, respectively. Several BSA derivatives also had the same reactivity, while benzanilide as the corresponding carbonyl compound did not rearrange under the same conditions. These results showed that the S-N bond could be cleaved selectively by EB irradiation but the C-N bond couldn't, which could take place only by the use of EB. The EB irradiation of phenyl p-toluenesulfonate (PTS) crystals gave not only Fries-type products but also the oxidation product. By comparing with the reactivity of liquid phenyl benzenesulfonate, the EB-induced Fries rearrangement was suggested to proceed under crystalline lattice restrictions. The G-values of arylsulfonamides and arylsulfonates were in the range of ca. 1-2 molecules per 100 eV of absorbed energy. This is the first Fries rearrangement via direct excitation by EB irradiation. (author)

  1. Focused-ion-beam induced interfacial intermixing of magnetic bilayers for nanoscale control of magnetic properties

    International Nuclear Information System (INIS)

    Burn, D M; Atkinson, D; Hase, T P A

    2014-01-01

    Modification of the magnetic properties in a thin-film ferromagnetic/non-magnetic bilayer system by low-dose focused ion-beam (FIB) induced intermixing is demonstrated. The highly localized capability of FIB may be used to locally control magnetic behaviour at the nanoscale. The magnetic, electronic and structural properties of NiFe/Au bilayers were investigated as a function of the interfacial structure that was actively modified using focused Ga + ion irradiation. Experimental work used MOKE, SQUID, XMCD as well as magnetoresistance measurements to determine the magnetic behavior and grazing incidence x-ray reflectivity to elucidate the interfacial structure. Interfacial intermixing, induced by low-dose irradiation, is shown to lead to complex changes in the magnetic behavior that are associated with monotonic structural evolution of the interface. This behavior may be explained by changes in the local atomic environment within the interface region resulting in a combination of processes including the loss of moment on Ni and Fe, an induced moment on Au and modifications to the spin-orbit coupling between Au and NiFe. (paper)

  2. A novel efficient coupled polynomial field interpolation scheme for higher order piezoelectric extension mode beam finite elements

    International Nuclear Information System (INIS)

    Sulbhewar, Litesh N; Raveendranath, P

    2014-01-01

    An efficient piezoelectric smart beam finite element based on Reddy’s third-order displacement field and layerwise linear potential is presented here. The present formulation is based on the coupled polynomial field interpolation of variables, unlike conventional piezoelectric beam formulations that use independent polynomials. Governing equations derived using a variational formulation are used to establish the relationship between field variables. The resulting expressions are used to formulate coupled shape functions. Starting with an assumed cubic polynomial for transverse displacement (w) and a linear polynomial for electric potential (φ), coupled polynomials for axial displacement (u) and section rotation (θ) are found. This leads to a coupled quadratic polynomial representation for axial displacement (u) and section rotation (θ). The formulation allows accommodation of extension–bending, shear–bending and electromechanical couplings at the interpolation level itself, in a variationally consistent manner. The proposed interpolation scheme is shown to eliminate the locking effects exhibited by conventional independent polynomial field interpolations and improve the convergence characteristics of HSDT based piezoelectric beam elements. Also, the present coupled formulation uses only three mechanical degrees of freedom per node, one less than the conventional formulations. Results from numerical test problems prove the accuracy and efficiency of the present formulation. (paper)

  3. 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.

  4. An electron beam induced current study of gallium nitride and diamond materials

    International Nuclear Information System (INIS)

    Cropper, A.D.; Moore, D.J.; Scott, C.S.; Green, R.

    1995-01-01

    The continual need for microelectronic devices that operate under severe electronic and environmental conditions (high temperature, high frequency, high power, and radiation tolerance) has sustained research in wide bandgap semiconductor materials. The properties suggest these wide-bandgap semiconductor materials have tremendous potential for military and commercial applications. High frequency bipolar transistors and field effect transistors, diodes, and short wavelength optical devices have been proposed using these materials. Although research efforts involving the study of transport properties in Gallium Nitride (GaN) and Diamond have made significant advances, much work is still needed to improve the material quality so that the electrophysical behavior of device structures can be further understood and exploited. Electron beam induced current (EBIC) measurements can provide a method of understanding the transport properties in Gallium Nitride (GaN) and Diamond. This technique basically consists of measuring the current or voltage transient response to the drift and diffusion of carriers created by a short-duration pulse of radiation. This method differs from other experimental techniques because it is based on a fast transient electron beam probe created from a high speed, laser pulsed photoemission system

  5. Electron-cloud instabilities and beam-induced multipacting in the LHC and in the VLHC

    International Nuclear Information System (INIS)

    Zimmermann, F.

    1997-10-01

    In the beam pipe of the Large Hadron Collider (LHC), photoemission and secondary emission give rise to a quasi-stationary electron cloud, which is established after a few buncn passages. The response of this electron cloud to a transversely displaced bunch resembles a short-range wakefield and can cause a fast instability. In additoin, beam-induced multipacting of the electrons may lead to an enhanced gas desorption and an associated pressure increase. In this paper the authors report preliminary simulation results of the electron-cloud build-up both in a dipole magnet and in a straight section of the LHC at top energy. The effective wakefield created by the electron cloud translates into an instability rise time of about 40 ms horizontally and 500 ms vertically. This rise time is not much larger than that of the resistive-wall instability at injection energy. Similar simulation studies show that the instability rise time for the proposed Very Large Hadron Collider (VLHC) is about 3--4 s in both trasnverse planes. The smaller growth rate in the VLHC, as compared with the LHC, is primarily due to the much lower bunch population

  6. Immunization with avian metapneumovirus harboring chicken Fc induces higher immune responses.

    Science.gov (United States)

    Paudel, Sarita; Easwaran, Maheswaran; Jang, Hyun; Jung, Ho-Kyoung; Kim, Joo-Hun; Shin, Hyun-Jin

    2016-07-15

    In this study, we evaluated the immune responses of avian metapneumovirus harboring chicken Fc molecule. Stable Vero cells expressing chicken Fc chimera on its surface (Vero-cFc) were established, and we confirmed that aMPV grown in Vero-cFc incorporated host derived chimera Fc into the aMPV virions. Immunization of chicken with aMPV-cFc induced higher level of antibodies and inflammatory cytokines; (Interferon (IFN)-γ and Interleukin (IL)-1β) compared to those of aMPV. The increased levels of antibodies and inflammatory cytokines in chicken immunized with aMPV-cFc were statistically significantly (p<0.05) to that of aMPV and control. The aMPV-cFc group also generated the highest neutralizing antibody response. After challenges, chickens immunized with aMPV-cFc showed much less pathological signs in nasal turbinates and trachea so that we could confirm aMPV-cFc induced higher protection than that of aMPV. The greater ability of aMPV harboring chicken Fc to that of aMPV presented it as a possible vaccine candidate. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Kinetic theory of beam-induced plasmas generalised to sophisticated atomic structures

    International Nuclear Information System (INIS)

    Peyraud-Cuenca, Nelly

    1987-01-01

    We present an analytic kinetic model available for all particle-beam-induced atomic plasmas, without any restriction on the distribution of electronic levels. The method is an iteration of the already known solution available only for the distribution of atomic levels as in the rare gases. We recall a universal atomic kinetic model which, independently of its applications to the study of efficient laser systems, might be a first step in the analytic investigation of molecular problems. Then, the iteration is systematically applied to all possible atomic structures whose number is increased by the non-local character of inelastic processes. We deduce a general analytic representation of the 'tail' of the electron distribution function as a ratio between non-local source terms and a combination of inelastic cross sections, from which we exhibit a physical interpretation and essential scaling laws. The theory is applied to sodium which is an important element in the research of efficient laser systems. (author)

  8. Electron-beam-induced current study of small-angle grain boundaries in multicrystalline silicon

    International Nuclear Information System (INIS)

    Chen, J.; Sekiguchi, T.; Xie, R.; Ahmet, P.; Chikyo, T.; Yang, D.; Ito, S.; Yin, F.

    2005-01-01

    Recombination activity of small-angle grain boundaries (SA GBs) in multicrystalline silicon (mc-Si) was studied by means of electron-beam-induced current (EBIC) technique. In the as-grown mc-Si, the EBIC contrasts of special Σ and random GBs were weak at both 300 and 100 K, whereas those of SA GBs were weak (<3%) at 300 K and strong (30-40%) at 100 K. In the contaminated mc-Si, SA GBs showed stronger EBIC contrast than Σ and R GBs at 300 K. It is indicated that SA GBs possess high density of shallow levels and are easily contaminated with Fe compared to other GBs

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

    DEFF Research Database (Denmark)

    van Dorp, Willem F.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

    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 growt......, the majority desorbs from the surface rather than dissociates to contribute to the deposit. It is important to take this into account during FEBIP experiments, for instance when determining fundamental process parameters such as the activation energy for desorption....... experiments compared to literature values is consistent with earlier findings by other authors. The discrepancy is attributed to electron-stimulated desorption, which is known to occur during electron irradiation. The data suggest that, of the W(CO)6 molecules that are affected by the electron irradiation...

  10. Field effect transistors and photodetectors based on nanocrystalline graphene derived from electron beam induced carbonaceous patterns

    International Nuclear Information System (INIS)

    Kurra, Narendra; Bhadram, Venkata Srinu; Narayana, Chandrabhas; Kulkarni, G U

    2012-01-01

    We describe a transfer-free method for the fabrication of nanocrystalline graphene (nc-graphene) on SiO 2 substrates directly from patterned carbonaceous deposits. The deposits were produced from the residual hydrocarbons present in the vacuum chamber without any external source by using an electron beam induced carbonaceous deposition (EBICD) process. Thermal treatment under vacuum conditions in the presence of Ni catalyst transformed the EBIC deposit into nc-graphene patterns, confirmed using Raman and TEM analysis. The nc-graphene patterns have been employed as an active p-type channel material in a field effect transistor (FET) which showed a hole mobility of ∼90 cm 2 V −1 s −1 . The nc-graphene also proved to be suitable material for IR detection. (paper)

  11. TEM study of the ion beam induced damage during 14 kev P+ implantation in silicon

    International Nuclear Information System (INIS)

    Rubanov, S.; Tamanyan, G.; Hudson, F.; Jamieson, D.N.; McCallum, J.C.; Prawer, S.

    2005-01-01

    The proposed silicon-based quantum computer architecture comprises an array of phosphorus donor atoms (qubits) positioned with nanometre accuracy beneath the surface of a semiconductor host, using a single ion implantation technique. The average depth of the implanted ions (the projected range R p ), lateral range R p 1, and the distribution of ions about that depth can be approximated as two-dimensional Gaussian with standard deviation ΔR p and ΔR p 1 (lateral straggle). Using transmission electron microscopy (TEM) we studied ion beam induced damage after 14 keV P + implantation in Si. The TEM images allowed us to compare the depth of the amorphous cluster formation to R p , R p 1, ΔR p 1 calculated from SRIM and hence determine evidence for the limitation on the accuracy of the position of the implanted ions imposed by straggling. (author). 4 refs., 3 figs

  12. Effects of focused ion beam induced damage on the plasticity of micropillars

    International Nuclear Information System (INIS)

    El-Awady, Jaafar A.; Woodward, Christopher; Dimiduk, Dennis M.; Ghoniem, Nasr M.

    2009-01-01

    The hardening effects of focused ion beam (FIB) induced damage produced during the fabrication of micropillars are examined by introducing a surface layer of nanosized obstacles into a dislocation dynamics simulation. The influence of the depth and strength of the obstacles as a function of pillar diameter is assessed parametrically. We show that for a selected set of sample sizes between 0.5 and 1.0 μm, the flow strength can increase by 10-20 %, for an obstacle strength of 750 MPa, and damage depth of 100 nm. On the other hand, for sizes larger and smaller than this range, the effect of damage is negligible. Results show that the obstacles formed during the FIB milling may be expected to alter the microstructure of micropillars, however, they have a negligible effect on the observed size-strength scaling laws.

  13. 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

    a further enhancement due to their annihilation at the end of the path. The work presented here aimed to establish and validate an experimental procedure for the quantification of plasmid and genomic DNA damage resulting from antiproton exposure. Immunocytochemistry was used to assess DNA damage in directly......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 offer...... and indirectly exposed human fibroblasts irradiated in both plateau and Bragg peak regions of a 126 MeV antiproton beam at CERN. Cells were stained post irradiation with an anti-γ-H2AX antibody. Quantification of the γ-H2AX foci-dose relationship is consistent with a linear increase in the Bragg peak region...

  14. Effects on cuytoskeleton system in pollen tube of pinus thunbergii induced by ion beam implantation

    International Nuclear Information System (INIS)

    Huang Qunce; Liang Qiuxia; Li Guopin

    2008-01-01

    The damage of the cytoskeleton system in the pollen and the pollen tube of Pinus thunbergii induced by ion beam implantation were researched. The results showed that the disorganization of the micro-tubules in the pollen tube was produced by N + implantation. The abnormal states of the pollen tube in morphology were very correlative with the abnormality of the cytoskeleton system. N + implantation was responsible for morphological abnormalities in the pollen tubes. There was a distinct correlation between the damage effects and the ion implantation dose. The add of dose caused more obvious damage effects. Furthermore, the state of the cytoskeleton system in the pollen tube was influenced by the ion implantation. The impact grade depended also on the ion implantation dose. (authors)

  15. Radiation-Induced Graft Polymerization: Gamma Radiation and Electron Beam Technology for Materials Development

    International Nuclear Information System (INIS)

    Madrid, Jordan F.; Cabalar, Patrick Jay; Lopez, Girlie Eunice; Abad, Lucille V.

    2015-01-01

    The formation of functional hybrid materials by attaching polymer chains with advantageous tailored properties to the surface of a base polymer with desirable bulk character is an attractive application of graft copolymerization. Radiation-induced graft polymerization (RIGP) has been a popular approach for surface modification of polymers because of its merits over conventional chemical processes. RIGP, which proceeds primarily via free radical polymerization process, has the advantages such as simplicity, low cost, control over process and adjustment of the materials composition and structure. RIGP can be performed using either electron beam or gamma radiation and it can be applied to both synthetic and natural polymers. These merits make RIGP a popular research topic worldwide. Moreover, the materials synthesized and produced via RIGP has found applications, and were proposed to produce continuous impact, in the fields of medicine, agriculture, pollution remediation, rare earth and valuable metals recovery, fuel cell membrane synthesis and catalysis to name a few. From 2012 our group has performed electron beam and gamma radiation-induced graft polymerization of various monomers onto polymers of natural and synthetic origins (e.g. monomers - glycidyl methacrylate, styrene, acrylonitrile, N,N-dimethylaminoethyl methacrylate; base polymers – polyethylene/polypropylene nonwoven fabric, polypropylene nonwoven fabric pineapple fibers, cellulose nonwoven fabric microcrystalline cellulose). We tested these grafted materials for heavy metals (Pb, Ni, Cu) and organic molecule removal from aqueous solutions and E. coli activity (using reversible addition fragmentation chain transfer RAFT mediated grafting). The results clearly showed the success of materials modified via FIGP in these applications. Currently, we are studying the applications of grafted materials on treatment of waste waters from tanning industry, value addition to abaca nonwoven fabrics cell sheet

  16. The mouse beam walking assay offers improved sensitivity over the mouse rotarod in determining motor coordination deficits induced by benzodiazepines.

    Science.gov (United States)

    Stanley, Joanna L; Lincoln, Rachael J; Brown, Terry A; McDonald, Louise M; Dawson, Gerard R; Reynolds, David S

    2005-05-01

    The mouse rotarod test of motor coordination/sedation is commonly used to predict clinical sedation caused by novel drugs. However, past experience suggests that it lacks the desired degree of sensitivity to be predictive of effects in humans. For example, the benzodiazepine, bretazenil, showed little impairment of mouse rotarod performance, but marked sedation in humans. The aim of the present study was to assess whether the mouse beam walking assay demonstrates: (i) an increased sensitivity over the rotarod and (ii) an increased ability to predict clinically sedative doses of benzodiazepines. The study compared the effects of the full benzodiazepine agonists, diazepam and lorazepam, and the partial agonist, bretazenil, on the mouse rotarod and beam walking assays. Diazepam and lorazepam significantly impaired rotarod performance, although relatively high GABA-A receptor occupancy was required (72% and 93%, respectively), whereas beam walking performance was significantly affected at approximately 30% receptor occupancy. Bretazenil produced significant deficits at 90% and 53% receptor occupancy on the rotarod and beam walking assays, respectively. The results suggest that the mouse beam walking assay is a more sensitive tool for determining benzodiazepine-induced motor coordination deficits than the rotarod. Furthermore, the GABA-A receptor occupancy values at which significant deficits were determined in the beam walking assay are comparable with those observed in clinical positron emission tomography studies using sedative doses of benzodiazepines. These data suggest that the beam walking assay may be able to more accurately predict the clinically sedative doses of novel benzodiazepine-like drugs.

  17. Antigenotoxic potential of Asparagus racemosus root extract against electron beam radiation induced micronuclei formation in Swiss albino mice

    International Nuclear Information System (INIS)

    Bhandary, B. Satheesh Kumar; Sharmila, K.P.; Suchetha Kumari, N.; Bhat, Vadish S.; Shetty, Jayaram; Peter, Alex John; Jose, Jerish M.; Fernandes, Ronald

    2016-01-01

    To evaluate the antigenotoxic potential of Asparagus Racemosus Root ethanolic extract (ARE) against electron beam radiation induced micronuclei formation in Swiss albino mice. Micronucleus assay was performed in the bone marrow of Swiss albino mice according to the method of Hosseinimehr et al., 2003. The experimental animals were orally administered 200 mg/kg body weight of ARE once daily for 15 consecutive days. At the end of experimental period, the animals were euthanized and the bone marrow was collected from the femur. Control (C), Radiation control (RC) and drug control (DC) group was also maintained. The number of radiation induced Micronucleated Polychromatic Erythrocytes (MnPCE) and Micronucleated Normochromatic Erythrocytes were decreased in the ARE treated mice which was statistically significant (p<0.05) compared to radiation control group. Present findings demonstrate the antigenotoxic potential of ARE against electron beam radiation induced micronuclei formation which may be attributed to scavenging of radiation-induced free radicals

  18. Contribution of Higher-Order Dispersion to Nonlinear Electron-Acoustic Solitary Waves in a Relativistic Electron Beam Plasma System

    International Nuclear Information System (INIS)

    Zahran, M.A.; El-Shewy, E.K.

    2008-01-01

    The nonlinear properties of solitary wave structures are reported in an unmagnetized collisionless plasma comprising of cold relativistic electron fluid, Maxwellian hot electrons, relativistic electron beam, and stationary ions. The Korteweg--de Vries (KdV) equation has been derived using a reductive perturbation theory. As the wave amplitude increases, the width and velocity of the soliton deviate from the prediction of the KdV equation i.e. the breakdown of the KdV approximation. On the other hand, to overcome this weakness we extend our analysis to obtain the KdV equation with fifth-order dispersion term. The solution of the resulting equation has been obtained

  19. Pressure control of a proton beam-irradiated water target through an internal flow channel-induced thermosyphon.

    Science.gov (United States)

    Hong, Bong Hwan; Jung, In Su

    2017-07-01

    A water target was designed to enhance cooling efficiency using a thermosyphon, which is a system that uses natural convection to induce heat exchange. Two water targets were fabricated: a square target without any flow channel and a target with a flow channel design to induce a thermosyphon mechanism. These two targets had the same internal volume of 8 ml. First, visualization experiments were performed to observe the internal flow by natural convection. Subsequently, an experiment was conducted to compare the cooling performance of both water targets by measuring the temperature and pressure. A 30-MeV proton beam with a beam current of 20 μA was used to irradiate both targets. Consequently, the target with an internal flow channel had a lower mean temperature and a 50% pressure drop compared to the target without a flow channel during proton beam irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Local deposition of high-purity Pt nanostructures by combining electron beam induced deposition and atomic layer deposition

    NARCIS (Netherlands)

    Mackus, A.J.M.; Mulders, J.J.L.; Sanden, van de M.C.M.; Kessels, W.M.M.

    2010-01-01

    An approach for direct-write fabrication of high-purity platinum nanostructures has been developed by combining nanoscale lateral patterning by electron beam induced deposition (EBID) with area-selective deposition of high quality material by atomic layer deposition (ALD). Because virtually pure,

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

    Czech Academy of Sciences Publication Activity Database

    Aad, G.; Abajyan, T.; Abbott, B.; Böhm, Jan; Chudoba, Jiří; Gallus, Petr; Gunther, Jaroslav; Jakoubek, Tomáš; Juránek, Vojtěch; Kepka, Oldřich; Kupčo, Alexander; Kůs, Vlastimil; Lokajíček, Miloš; Marčišovský, Michal; Mikeštíková, Marcela; Myška, Miroslav; Němeček, Stanislav; Růžička, Pavel; Schovancová, Jaroslava; Šícho, Petr; Staroba, Pavel; Svatoš, Michal; Taševský, Marek; Tic, Tomáš; Valenta, J.; Vrba, Václav

    2013-01-01

    Roč. 8, Jul (2013), s. 1-58 ISSN 1748-0221 R&D Projects: GA MŠk(CZ) LG13009 Institutional support: RVO:68378271 Keywords : background * induced * semiconductor detector * pixel * muon * spectrometer * jet * single production * ATLAS * calorimeter * new physics * beam Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.526, year: 2013

  2. Role of lutein in alleviating the effects of electron beam radiation induced hematological and biochemical changes in Swiss albino mice

    International Nuclear Information System (INIS)

    Vidya, V.; Krishna, A.P.; Patil, Shrikant; Fernandes, Ronald

    2016-01-01

    Lutein is a naturally occurring xanthophyll pigment derived from α-carotene. It is abundantly present in Tagetes erecta L. (marigold) and also present in a few vegetables, fruits and in animal sources. Lutein was evaluated for its protective role in electron beam radiation induced damages in Swiss albino mice. The drug was optimized for its radioprotective activity

  3. 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.

  4. Electron beam induced cationic polymerization of epoxy resins. Dependence of Tg on conversion

    International Nuclear Information System (INIS)

    Degrand, H.; Cazaux, F.; Coqueret, X.

    2002-01-01

    Complete text of publication follows. The high-energy radiation curing of monomer blends polymerizing by a free radical or by a cationic mechanism receives increasing attention in the perspective of high performance composite materials. In the present work, we have focused our attention on epoxy formulations as models of the matrices polymerizing by a cationic mechanism that could be used in fiber-reinforced composites for aerospace applications. We have examined the progress of the electron beam (EB) induced polymerization of diglycidylether of bisphenol A (DGEBA) in the presence of a diaryliodonium salt (DAIS) by FTIR spectroscopy and by dynamic mechanical thermal analysis (DMA). The obtained results allow to draw the gradual increase of the temperature for the network thermomechanical transition (T a , associated with the glass transition temperature T g ) over a broad range of conversion (p) and reveal a peculiar behavior at high conversion. In this domain (p > 0.90), the material's T g is shown to decrease when conversion approaches unity. Moreover, the post-irradiation thermal treatment of the materials, that generally yields effective 'dark curing', appears to induce a decrease of T g , with an amplitude correlated with the amount of DAIS in the formulation. Owing to the particular nature of the propagating centers in cationic polymerisation, the thermal relaxation of ionic clusters trapped in the glassy matrix can be reasonably invoked as a possible cause for this behavior

  5. Importance of beam-beam tune spread to collective beam-beam instability in hadron colliders

    International Nuclear Information System (INIS)

    Jin Lihui; Shi Jicong

    2004-01-01

    In hadron colliders, electron-beam compensation of beam-beam tune spread has been explored for a reduction of beam-beam effects. In this paper, effects of the tune-spread compensation on beam-beam instabilities were studied with a self-consistent beam-beam simulation in model lattices of Tevatron and Large Hodron Collider. It was found that the reduction of the tune spread with the electron-beam compensation could induce a coherent beam-beam instability. The merit of the compensation with different degrees of tune-spread reduction was evaluated based on beam-size growth. When two beams have a same betatron tune, the compensation could do more harm than good to the beams when only beam-beam effects are considered. If a tune split between two beams is large enough, the compensation with a small reduction of the tune spread could benefit beams as Landau damping suppresses the coherent beam-beam instability. The result indicates that nonlinear (nonintegrable) beam-beam effects could dominate beam dynamics and a reduction of beam-beam tune spread by introducing additional beam-beam interactions and reducing Landau damping may not improve the stability of beams

  6. Fate of induced mutations in higher plants with special emphasis on sexually reproducing species

    International Nuclear Information System (INIS)

    Cornu, Andre

    1978-01-01

    A mutation induced in a plant somatic cell has to overcome quite many difficulties before being isolated and utilized as a marker in a mutated line. If induced in a meristem, three conditions must be fulfilled for the mutation to be transmitted to the subsequent generation: it must be compatible with normal cell multiplication, it must be located in a cell mass that will provide an inflorescence, and it must be in the sporogenetic layer (t2). Under these conditions, or if it is induced in a gamete or in a zygote, the mutation enters a first cycle of sexual reproduction. Meiosis and the subsequent haploid phase constitute severe screening steps for many chromosome aberrations. Studies on Petunia performed by means of marker genes show that male and female gametic viabilities are drastically impaired by deletions. However, a deficient chromosome can be transmitted when the losss of information is compensated for by homologous information as, for example, diploid gametes from tetraploids or disomic gametes resulting from non-disjunction. If partial or complete sterility, whether sporo- or gametophytic, is avoided, then the mutation can be transmitted to the next generation in heterozygous state. When becoming homozygous, the mutation may have effects such that its use can be most difficult. This is the case when this mutation causes rather early lethality or severe sterility. Thus, in higher plants, one faces several cases of powerful and efficient selection against mutations. On the basis of experiments carried out on Petunia, the per locus mutation rate of practical interest ranges between I and 5/10000M 1 plants. Practical conclusions are drawn about which organ should be treated, which mutagen at what dose should be used according to the scope of the research undertaken [fr

  7. Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

    Directory of Open Access Journals (Sweden)

    Guocai Li

    Full Text Available Neisseria gonorrhoeae (N. gonorrhoeae outer membrane protein reduction modifiable protein (Rmp has strong immunogenicity. However, anti-Rmp antibodies block rather than preserve the antibacterial effects of protective antibodies, which hampers the development of vaccines for gonococcal infections. We herein constructed an Rmp deletion mutant strain of N. gonorrhoeae by gene homologous recombination. The 261-460 nucleotide residues of Rmp gene amplified from N. gonorrhoeae WHO-A strain were replaced with a kanamycin-resistant Kan gene amplified from pET-28a. The resultant hybridized DNA was transformed into N. gonorrhoeae WHO-A strain. PCR was used to screen the colonies in which wild-type Rmp gene was replaced with a mutant gene fragment. Western blotting revealed that the Rmp deletion mutant strain did not express Rmp protein. Rmp deletion did not alter the morphological and Gram staining properties of the mutant strain that grew slightly more slowly than the wild-type one. Rmp gene mutated stably throughout 25 generations of passage. Antibody-mediated complement-dependent cytotoxicity assay indicated that the antibodies induced by the mutant strain had evidently higher bactericidal activities than those induced by the wild-type strain. Further modification of the Rmp deletion mutant strain is still required in the development of novel live attenuated vaccines for gonorrhea by Opa genes deletion or screening of phenotypic variant strains that do not express Opa proteins.

  8. 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.

  9. 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.

  10. 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.

  11. Images of paraffin monolayer crystals with perfect contrast: minimization of beam-induced specimen motion

    Science.gov (United States)

    Glaeser, R.M.; McMullan, G.; Faruqi, A.R.; Henderson, R.

    2013-01-01

    Quantitative analysis of electron microscope images of organic and biological two-dimensional crystals has previously shown that the absolute contrast reached only a fraction of that expected theoretically from the electron diffraction amplitudes. The accepted explanation for this is that irradiation of the specimen causes beam-induced charging or movement, which in turn causes blurring of the image due to image or specimen movement. In this paper, we used three different approaches to try to overcome this image-blurring problem for monolayer crystals of paraffin. Our first approach was to use an extreme form of spotscan imaging, in which a single image was assembled on film by the successive illumination of up to 50,000 spots each of diameter around 7nm. The second approach was to use the Medipix II detector with its zero-noise readout to assemble a time-sliced series of images of the same area in which each frame from a movie with up to 400 frames had an exposure of only 500 electrons. In the third approach, we simply used a much thicker carbon support film to increase the physical strength and conductivity of the support. Surprisingly, the first two methods involving dose fractionation respectively in space or time produced only partial improvements in contrast whereas the third approach produced many virtually perfect images, in which the absolute contrast predicted from the electron diffraction amplitudes was observed in the images. We conclude that it is possible to obtain consistently almost perfect images of beam-sensitive specimens if they are attached to an appropriately strong and conductive support, but great care is needed in practice and the problem of how best to image ice-embedded biological structures in the absence of a strong, conductive support film requires more work. PMID:21185452

  12. A comparison of ion beam measurements by retarding field energy analyzer and laser induced fluorescence in helicon plasma devices

    Energy Technology Data Exchange (ETDEWEB)

    Gulbrandsen, N., E-mail: njal.gulbrandsen@uit.no; Fredriksen, Å. [Department of Physics and Technology, UiT The Arctic University of Norway, 9037 Tromsø (Norway); Carr, J. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States); Department of Physics, Texas Lutheran University, Seguin, Texas 78155 (United States); Scime, E. [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506 (United States)

    2015-03-15

    Both Laser-Induced Fluorescence (LIF) and Retarding Field Energy Analyzers (RFEA) have been applied to the investigation of beams formed in inductively coupled helicon plasmas. While the LIF technique provides a direct measurement of the velocity distribution in the plasma, the RFEA measures ion flux as a function of a retarding potential. In this paper, we present a method to compare the two techniques, by converting the LIF velocity distribution to an equivalent of a RFEA measurement. We applied this method to compare new LIF and RFEA measurements in two different experiments; the Hot Helicon Experiment (HELIX) - Large Experiment on Instabilities and Anisotropies (LEIA) at West Virginia University and Njord at University of Tromsø. We find good agreement between beam energies of the two methods. In agreement with earlier observations, the RFEA is found to measure ion beams with densities too low for the LIF to resolve. In addition, we present measurements of the axial development of the ion beam in both experiments. Beam densities drop exponentially with distance from the source, both in LIF and RFEA measurements. The effective quenching cross section from LIF in LEIA is found to be σ{sub b,*}=4×10{sup −19} m{sup 2}, and the effective beam collisional cross sections by RFEA in Njord to be σ{sub b}=1.7×10{sup −18} m{sup 2}.

  13. Quantitative assessment of the ion-beam irradiation induced direct damage of nucleic acid bases through FTIR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qing, E-mail: huangq@ipp.ac.cn [Key Laboratory of Ion Beam Bio-engineering, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China); University of Science and Technology of China, Hefei 230029, Anhui (China); Su, Xi; Yao, Guohua; Lu, Yilin; Ke, Zhigang; Liu, Jinghua; Wu, Yuejin; Yu, Zengliang [Key Laboratory of Ion Beam Bio-engineering, Institute of Technical Biology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences (China)

    2014-07-01

    Energetic particles exist ubiquitously in nature, and when they hit DNA molecules in organisms, they may induce critical biological effects such as mutation. It is however still a challenge to measure directly and quantitatively the damage imposed by the energetic ions on target DNA molecules. In this work we attempted to employ Fourier transformation infrared (FTIR) spectroscopy to assess the ion-induced direct damage of four nucleic acid bases, namely, thymine (T), cytosine (C), guanine (G), and adenine (A), which are the building blocks of DNA molecules. The samples were prepared as thin films, irradiated by argon ion-beams at raised ion fluences, and in the meantime measured by FTIR spectroscopy for the damage in a quasi-in-situ manner. It was found that the low-energy ion-beam induced radiosensitivity of the four bases shows the sequence G > T > C > A, wherein the possible mechanism was also discussed.

  14. Electron and photon-beam induced reactions of adsorbed disilane: Low-temperature thin-film growth

    International Nuclear Information System (INIS)

    Bozso, F.; Avouris, Ph.

    1991-01-01

    Electrons and photons of sufficient energy can cause fragmentation and desorption of adsorbed molecules or fragments of them, by inducing electronic excitations to dissociative states. The surface species after such excitations are mostly of highly reactive radical character, which readily react with the substrate and with other molecular or radical species in the adsorbed layer. This paper discusses the adsorption, thermal and electron/photon-beam induced reactions of disilane, oxygen and ammonia on Si(111)-7x7, and the electron/photon-induced growth of silicon, silicon dioxide and silicon nitride films at 100K

  15. Prospects for measuring G{sub M{sub N}} in CLAS with higher CEBAF beam energies

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, W. [CEBAF, Newport News, VA (United States)

    1994-04-01

    The possibility exists for extending a planned measurement of the neutron magnetic form factor to higher values of momentum transfer. The theoretical interest and the experimental method are described. Problems associated with higher Q{sup 2} measurements are discussed. It is concluded that measurements of moderate precision may be possible up to a Q{sup 2} of 8-9.5 GeV{sup 2}, more than doubling the range of the data currently available.

  16. MOLECULAR BEAM STUDIES OF IR LASER INDUCED MULTIPHOTON DISSOCIATION AND VIBRATIONAL PREDISSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yuan T.; Shen, Y. Ron

    1980-06-01

    The advancement of crossed molecular beam methods, modern spectroscopy and laser technology allows us to observe chemical reactions on atomic and molecular levels in great detail. After a brief history of crossed molecular beams studies, the author describes and discusses the universal molecular beam apparatus and gives examples of crossed molecular beam studies. The crossed beam technique is compared to other techniques used to provide microscopic information on reaction dynamics. Application of crossed laser and molecular beam studies to the problem of IR multiphoton dissociation of polyatomic molecules is discussed. Study of vibrational predissociation of hydrogen-bonded and van der Waals molecular clusters are discussed. Future cases that the author considers worth pursuing that could benefit from the collisionless environment of molecular beams are enumerated.

  17. 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.

  18. Soccer small-sided games in young players: rule modification to induce higher physiological responses

    Directory of Open Access Journals (Sweden)

    J Halouani

    2017-04-01

    Full Text Available The aim of this study was to identify the physiological responses of 3 forms of players’ numbers during two different games rules of small-sided games (SSG: stop-ball vs. small-goals rules. Eighteen youth amateur soccer players (age 13.5±0.7 years; height 168.9±6.1cm; body mass 63.1±7.7 kg participated in this study and performed 3 SSGs with varying players’ number (2vs.2; 3vs.3 and 4vs.4: stop-ball SSG (SB-SSG vs. small-goals SSG (SG-SSG in a randomized and counter-balanced order on a constant pitch dimension (20×25m. The players performed 4×4 min SSG with 2-min of passive recovery in-between. Heart rate (HR, (expressed in bpm and % HRmax, lactate ([La-], and rating of perceived exertion (RPE were collected during each session. SB-SSG induced the higher HR values in comparison with the SG-SSG for the 3 game formats (2vs.2; 3vs.3 and 4vs.4. Also, compared with SG-SSG, SB-SSG induced the higher HR values during 2vs.2 compared with 4vs.4 games rules (178 vs. 174 and 175 vs. 171 bpm, respectively. However, the SB-SSG was more intense compared with SG-SSG in the 2 vs. 2 game rule compared with the two others (3 vs.3 and 4 vs. 4 for [La-] and RPE (7.58 vs. 7; 7.25 vs. 6.75 and 6.5 vs. 6.16 mmol ∙ L-1, and 7.75 vs. 7.33; 7.41 vs. 7.08 and 7.16 vs. 6.83, respectively. Therefore, the use of 2 vs. 2 and 3 vs. 3 SSG with SB-SSG seems to represent an alternative to coaches to increase cardiovascular and metabolic demands in youth soccer players.

  19. Soccer small-sided games in young players: rule modification to induce higher physiological responses

    Science.gov (United States)

    Chtourou, H; Dellal, A; Chaouachi, A; Chamari, K

    2017-01-01

    The aim of this study was to identify the physiological responses of 3 forms of players’ numbers during two different games rules of small-sided games (SSG: stop-ball vs. small-goals rules). Eighteen youth amateur soccer players (age 13.5±0.7 years; height 168.9±6.1cm; body mass 63.1±7.7 kg) participated in this study and performed 3 SSGs with varying players’ number (2vs.2; 3vs.3 and 4vs.4): stop-ball SSG (SB-SSG) vs. small-goals SSG (SG-SSG) in a randomized and counter-balanced order on a constant pitch dimension (20×25m). The players performed 4×4 min SSG with 2-min of passive recovery in-between. Heart rate (HR), (expressed in bpm and % HRmax), lactate ([La-]), and rating of perceived exertion (RPE) were collected during each session. SB-SSG induced the higher HR values in comparison with the SG-SSG for the 3 game formats (2vs.2; 3vs.3 and 4vs.4). Also, compared with SG-SSG, SB-SSG induced the higher HR values during 2vs.2 compared with 4vs.4 games rules (178 vs. 174 and 175 vs. 171 bpm, respectively). However, the SB-SSG was more intense compared with SG-SSG in the 2 vs. 2 game rule compared with the two others (3 vs.3 and 4 vs. 4) for [La-] and RPE (7.58 vs. 7; 7.25 vs. 6.75 and 6.5 vs. 6.16 mmol ∙ L-1, and 7.75 vs. 7.33; 7.41 vs. 7.08 and 7.16 vs. 6.83, respectively). Therefore, the use of 2 vs. 2 and 3 vs. 3 SSG with SB-SSG seems to represent an alternative to coaches to increase cardiovascular and metabolic demands in youth soccer players. PMID:28566810

  20. The analysis of dynamic characteristics and wind-induced displacement response of space Beam String Structure

    Directory of Open Access Journals (Sweden)

    Chen Yong Jian

    2018-01-01

    Full Text Available The Beam String Structure structural system, also called BSS, has the advantages of lighter dead weight and greater flexibility. The wind load is the main design control factor. The dynamic characteristics and wind-induced displacement response of BSS are studied by the finite element method. The roof structure of the stadium roof of the Fuzhou Olympic Sports Center is the engineering background. 1The numerical model was built by ANSYS, by shape finding, determine the initial stress state of structural members such as external cables; 2From the analysis of dynamic characteristics, the main mode of vibration is the vibration of cables; 3The wind speed spectrum of MATLAB generation structure is obtained by AR method, the structural response of the structure under static wind load and fluctuating wind load is calculated. From the analysis result, considering the equivalent static wind load of BSS , the design of adverse wind is not safe, and the fluctuating wind load should be taken into account.

  1. 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.

  2. Methods of optimising ion beam induced charge collection of polycrystalline silicon photovoltaic cells

    International Nuclear Information System (INIS)

    Witham, L.C.G.; Jamieson, D.N.; Bardos, R.A.

    1998-01-01

    Ion Beam Induced Charge (IBIC) is a valuable method for the mapping of charge carrier transport and recombination in silicon solar cells. However performing IBIC analysis of polycrystalline silicon solar cells is problematic in a manner unlike previous uses of IBIC on silicon-based electronic devices. Typical solar cells have a surface area of several square centimeters and a p-n junction thickness of only few microns. This means the cell has a large junction capacitance in the many nanoFarads range which leads to a large amount of noise on the preamplifier inputs which typically swamps the transient IBIC signal. The normal method of improving the signal-to-noise (S/N) ratio by biasing the junction is impractical for these cells as the low-quality silicon used leads to a large leakage current across the device. We present several experimental techniques which improve the S/N ratio which when used together should make IBIC analysis of many low crystalline quality devices a viable and reliable procedure. (authors)

  3. Experimental setup and first measurement of DNA damage induced along and around an antiproton beam

    International Nuclear Information System (INIS)

    Kavanagh, J.N.; Currell, F.J.; Prise, K.M.; Schettino, G.; Currell, F.J.; Timson, D.J.; Holzscheiter, M.H.; Bassler, N.; Herrmann, R.

    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 offer a further enhancement due to their annihilation at the end of the path. The work presented here aimed to establish and validate an experimental procedure for the quantification of plasmid and genomic DNA damage resulting from antiproton exposure. Immunocytochemistry was used to assess DNA damage in directly and indirectly exposed human fibroblasts irradiated in both plateau and Bragg peak regions of a 126 MeV antiproton beam at CERN. Cells were stained post irradiation with an anti-γ-H2AX antibody. Quantification of the γ-H2AX foci-dose relationship is consistent with a linear increase in the Bragg peak region. A qualitative analysis of the foci detected in the Bragg peak and plateau region indicates significant differences highlighting the different severity of DNA lesions produced along the particle path. Irradiation of desalted plasmid DNA with 5 Gy antiprotons at the Bragg peak resulted in a significant portion of linear plasmid in the resultant solution. (authors)

  4. Electron beam induced graft-polymerization of methyl methacrylate onto polyethylene films at high dose rates

    International Nuclear Information System (INIS)

    Mori, Koji; Koshiishi, Kenji; Masuhara, Ken-ichi

    1991-01-01

    Electron beam induced graft-polymerization by the mutual irradiation technique of methyl methacrylate on the surface of low density polyethylene films (LD) and high density polyethylene films (HD) was investigated at high dose rates over 10 Mrad per second. Graft-polymerization mechanisms were discussed on the basis of O 2 permeability, tensile strength, elongation at break, and surface tension of the grafted films. As the degree of grafting increased, the O 2 permeability of LD decreased, while that of HD little changed at the grafting up to 4 ∼ 5 %. This indicates that the grafting occurred in the amorphous regions for LD and occurred in the amorphous regions in the neighborhood of crystalline regions for HD. For HD, when the degree of the grafting surpassed 4 ∼ 5 %, the O 2 permeability, tensile strength, elongation at break, and surface tension decreased with an increase in the degree of grafting. It was assumed that rapid grafting in the amorphous regions in the neighborhood of crystalline regions caused the increase in local temperature by the heat of polymerization, and the viscosity of polyethylene in the amorphous regions decreased with an increase in temperature. As a result, the graft chains, which formed micro domain structure, condensed in the amorphous regions and the domain increased in size. (author)

  5. Kinetic Transition of Crystal Morphology from Nanoparticles to Dendrites during Electron Beam Induced Deposition of Gold

    Science.gov (United States)

    Park, Jeung Hun; Schneider, Nicholas; Bau, Haim; Kodambaka, Suneel; Ross, Frances

    2015-03-01

    We studied the kinetic transition from compact nanoparticle to dendritic morphology during electron beam-induced Au deposition using in situ liquid cell-based transmission electron microcopy. Radiolysis of water by electrons generates radicals and molecular species. Hydrated electrons and hydrogen and hydroxide radicals can act as reducing agents and initiate the reduction of the water-soluble precursor, HAuCl4, resulting in the precipitation of Au as nanostructures. We tracked nucleation, growth, and morphological transition of Au from movies recorded in situ, as a function of irradiated dose and liquid thickness. We identified several distinct regimes that depend on the irradiation time: (1) nucleation; (2) linear volumetric growth; (3) formation of dendritic structures; (4) coalescence and dissolution. A diffusion and reaction model for the radiolytic species and metal ions in the confined geometry of the irradiated volume is used to understand the nucleation sites and morphological transitions. We finally describe how nanoparticles can be made to grow in a stepwise manner by switching the supply of Au ions on and off electrochemically, and discuss possibilities for creating more complex nanostructures. This research was partially funded by the National Science Foundation (DMR-1310639, CMMI-1129722, and CBET-1066573).

  6. Electron-beam-induced welding of 3D nano-objects from beneath

    International Nuclear Information System (INIS)

    Moskalenko, A V; Burbridge, D J; Viau, G; Gordeev, S N

    2007-01-01

    Exposure of a sample to the electron beam in a scanning electron microscope (SEM) results in the growth of a film of amorphous carbon due to decomposition of hydrocarbon molecules, which are always present in small quantities in the SEM chamber. This growth is induced mainly by secondary electrons backscattered by atoms of both the sample and substrate. We show that, because the secondary electrons are spread beyond the exposed area, this deposit can be grown in areas of geometric shadow and therefore can be used for bonding of different complex 3D nano-objects to a substrate. This is demonstrated by welding 100 nm Fe-Co-Ni nanoparticles to the surface of 2D graphite. The tip of an atomic force microscope was used to probe the mechanical properties of the formed nanostructures. We observed that, for layers thicker than 25 nm, the nanoparticle is bonded so strongly that it is easier to break the particle than to separate it from the substrate

  7. The characterization of high quality multicrystalline silicon by the electron beam induced current method

    International Nuclear Information System (INIS)

    Chen, J; Sekiguchi, T; Nara, S; Yang, D

    2004-01-01

    Multicrystalline silicon (mc-Si) manufactured by a multi-stage solidification control casting method has been characterized by the electron beam induced current (EBIC) method. The average diffusion length of the ingot was over 250 μm, which was much longer than that of conventional mc-Si. The EBIC study revealed that the electrical activities of grain boundaries (GBs) varied with the ingot position due to the impurity contamination level. The main impurity detected was iron. The concentration of iron in the central position was much lower than that at the bottom and top positions. GBs in the central position showed no significant EBIC contrast at 300 K, suggesting low contamination level. GBs in the top and bottom positions, however, showed strong EBIC contrast at 300 K, suggesting high contamination level. At 100 K, a denuded zone with bright contrast developed around GBs in the top and bottom positions. The existence of the denuded zone suggested that impurities were gettered at the GBs. It was considered that the variation of the diffusion length in the ingot was related to the variation of recombination activities of GBs in the different positions, which mainly depended on the impurity contamination

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

    KAUST Repository

    Tabet, Nouar A.; Al-Sayoud, Abduljabar; Said, Seyed; Yang, Xiaoming; Yang, Yang; Syed, Ahad A.; Diallo, Elhadj; Wang, Zhihong; Wang, Xianbin; Johlin, Eric; Simmons, Christine; Buonassisi, Tonio

    2012-01-01

    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. 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.

  10. Positron lifetime measurements and positron-annihilation induced auger electron spectroscpy using slow positron beams; Teisoku yodenshi bimu wo mochiita yodenshi jumyo sokutei oyobi yodenshi shometsu reiki oje denshi bunko

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, R. [Electrotechnical Lab., Tsukuba (Japan)

    1996-02-20

    Slow positron beam with less than several eV can be controlled freely such as accelerating, throttling the beam size, shortening the pulse or making pulse with short time width and so forth. These low positron beams are applied to various measurements like Doppler broadening measurement of annihilation {gamma} rays or lifetime measurement of positron, and secondary particle measurements using positron microscope, positron electron ray diffraction, flight time method and so forth. In particular, these recent years, high intensity slow positron beams were possible using accelerators like electron linac and its application is increasing. In this report, pulse shortening method for high intensity slow positron beam, and incidence energy variable positron lifetime measurement method using this slow pulsed beam and flight time type positron-annihilation-induced auger electron spectroscopy are outlined. In future, these measurements can be possible to carry out with high resolution and also with high counting rate if higher intensity monochromatic excellent positron beam than present one is produced. 31 refs., 5 figs.

  11. Comparison of laser-induced surface damage density measurements with small and large beams: toward representativeness

    International Nuclear Information System (INIS)

    Lamaignere, Laurent; Dupuy, Gabriel; Donval, Thierry; Grua, Pierre; Bercegol, Herve

    2011-01-01

    Pulsed laser damage density measurements obtained with diverse facilities are difficult to compare, due to the interplay of numerous parameters, such as beam area and pulse geometry, which, in operational large beam conditions, are very different from laboratory measurements. This discrepancy could have a significant impact; if so, one could not even pretend that laser damage density control is a real measurement process. In this paper, this concern is addressed. Tests with large beams of centimeter size on a high-power laser facility have beam performed according to a parametric study and are compared to small beam laboratory tests. It is shown that laser damage densities obtained with large and small beams are equal, within calculated error bars.

  12. Inhibition of crossed-beam energy transfer induced by expansion-velocity fluctuations

    Science.gov (United States)

    Neuville, C.; Glize, K.; Loiseau, P.; Masson-Laborde, P.-E.; Debayle, A.; Casanova, M.; Baccou, C.; Labaune, C.; Depierreux, S.

    2018-04-01

    Crossed-beam energy transfer between three laser beams has been experimentally investigated in a flowing plasma. Time-evolution measurements of the amplification of a first beam by a second beam highlighted the inhibition of energy transfer by hydrodynamic modifications of the plasma in the crossing volume due to the propagation of a third beam. According to 3D simulations and an analytical model, it appears that the long-wavelength expansion-velocity fluctuations produced by the propagation of the third beam in the crossing volume are responsible for this mitigation of energy transfer. This effect could be a cause of the over-estimation of the amount of the transferred energy in indirect-drive inertial confinement fusion experiments. Besides, tuning such long-wavelength fluctuations could be a way to completely inhibit CBET at the laser entrance holes of hohlraums.

  13. Images of paraffin monolayer crystals with perfect contrast: Minimization of beam-induced specimen motion

    International Nuclear Information System (INIS)

    Glaeser, R.M.; McMullan, G.; Faruqi, A.R.; Henderson, R.

    2011-01-01

    Quantitative analysis of electron microscope images of organic and biological two-dimensional crystals has previously shown that the absolute contrast reached only a fraction of that expected theoretically from the electron diffraction amplitudes. The accepted explanation for this is that irradiation of the specimen causes beam-induced charging or movement, which in turn causes blurring of the image due to image or specimen movement. In this paper, we used three different approaches to try to overcome this image-blurring problem in monolayer crystals of paraffin. Our first approach was to use an extreme form of spotscan imaging, in which a single image was assembled on film by the successive illumination of up to 50,000 spots, each of a diameter of around 7 nm. The second approach was to use the Medipix II detector with its zero-noise readout to assemble a time-sliced series of images of the same area in which each frame from a movie with up to 400 frames had an exposure of only 500 electrons. In the third approach, we simply used a much thicker carbon support film to increase the physical strength and conductivity of the support. Surprisingly, the first two methods involving dose fractionation in space or time produced only partial improvements in contrast whereas the third approach produced many virtually perfect images, where the absolute contrast predicted from the electron diffraction amplitudes was observed in the images. We conclude that it is possible to obtain consistently almost perfect images of beam-sensitive specimens if they are attached to an appropriately strong and conductive support; however great care is needed in practice and the problem remains of how to best image ice-embedded biological structures in the absence of a strong, conductive support film. -- Research Highlights: →Three ideas were tested to improve the contrast of images of an organic specimen. →High-resolution images of paraffin on thick carbon films can have perfect contrast

  14. Images of paraffin monolayer crystals with perfect contrast: Minimization of beam-induced specimen motion

    Energy Technology Data Exchange (ETDEWEB)

    Glaeser, R.M. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); McMullan, G.; Faruqi, A.R. [MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH (United Kingdom); Henderson, R., E-mail: rh15@mrc-lmb.cam.ac.uk [MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH (United Kingdom)

    2011-01-15

    Quantitative analysis of electron microscope images of organic and biological two-dimensional crystals has previously shown that the absolute contrast reached only a fraction of that expected theoretically from the electron diffraction amplitudes. The accepted explanation for this is that irradiation of the specimen causes beam-induced charging or movement, which in turn causes blurring of the image due to image or specimen movement. In this paper, we used three different approaches to try to overcome this image-blurring problem in monolayer crystals of paraffin. Our first approach was to use an extreme form of spotscan imaging, in which a single image was assembled on film by the successive illumination of up to 50,000 spots, each of a diameter of around 7 nm. The second approach was to use the Medipix II detector with its zero-noise readout to assemble a time-sliced series of images of the same area in which each frame from a movie with up to 400 frames had an exposure of only 500 electrons. In the third approach, we simply used a much thicker carbon support film to increase the physical strength and conductivity of the support. Surprisingly, the first two methods involving dose fractionation in space or time produced only partial improvements in contrast whereas the third approach produced many virtually perfect images, where the absolute contrast predicted from the electron diffraction amplitudes was observed in the images. We conclude that it is possible to obtain consistently almost perfect images of beam-sensitive specimens if they are attached to an appropriately strong and conductive support; however great care is needed in practice and the problem remains of how to best image ice-embedded biological structures in the absence of a strong, conductive support film. -- Research Highlights: {yields}Three ideas were tested to improve the contrast of images of an organic specimen. {yields}High-resolution images of paraffin on thick carbon films can have perfect

  15. 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.

  16. Observation of laser-induced elastic waves in agar skin phantoms using a high-speed camera and a laser-beam-deflection probe.

    Science.gov (United States)

    Laloš, Jernej; Gregorčič, Peter; Jezeršek, Matija

    2018-04-01

    We present an optical study of elastic wave propagation inside skin phantoms consisting of agar gel as induced by an Er:YAG (wavelength of 2.94 μm) laser pulse. A laser-beam-deflection probe is used to measure ultrasonic propagation and a high-speed camera is used to record displacements in ablation-induced elastic transients. These measurements are further analyzed with a custom developed image recognition algorithm utilizing the methods of particle image velocimetry and spline interpolation to determine point trajectories, material displacement and strain during the passing of the transients. The results indicate that the ablation-induced elastic waves propagate with a velocity of 1 m/s and amplitudes of 0.1 mm. Compared to them, the measured velocities of ultrasonic waves are much higher, within the range of 1.42-1.51 km/s, while their amplitudes are three orders of magnitude smaller. This proves that the agar gel may be used as a rudimental skin and soft tissue substitute in biomedical research, since its polymeric structure reproduces adequate soft-solid properties and its transparency for visible light makes it convenient to study with optical instruments. The results presented provide an insight into the distribution of laser-induced elastic transients in soft tissue phantoms, while the experimental approach serves as a foundation for further research of laser-induced mechanical effects deeper in the tissue.

  17. Beam diagnostics

    International Nuclear Information System (INIS)

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-01-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the open-quotes Boosterclose quotes and open-quotes ATLASclose quotes linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates

  18. Significant efficiency enhancement in thin film solar cells using laser beam-induced graphene transparent conductive electrodes

    OpenAIRE

    Thekkekara, L. V.; Cai, Bouyan

    2018-01-01

    Thin film solar cells have been attractive for decades in advanced green technology platforms due to its possibilities to be integrated with buildings and on-chip applications. However, the bottleneck issues involved to consider the current solar cells as a major electricity source includes the lower efficiencies and cost-effectiveness. We numerically demonstrate the concept of the absorption enhancement in thin-film amorphous silicon solar cells using the laser beam-induced graphene material...

  19. PH-Induced Nanosegregation of Ritonavir to Lyotropic Liquid Crystal of Higher Solubility Than Crystalline Polymorphs

    International Nuclear Information System (INIS)

    Rodriguez-Spong, B.; Acciacca, A.; Fleisher, D.; Rodriguez-Hornedo, N.

    2009-01-01

    Birefringent spherical vesicles of ritonavir (RTV) are formed by increasing the pH of aqueous solutions from 1 to 3 or to 7 and by addition of water to ethanol solutions at room temperature. Increasing the pH creates supersaturation levels of 30--400. Upon this change in pH, the solutions become translucent, implying that some kind of RTV assembly was formed. Small spherical vesicles of narrow size distribution are detectable only after a few hours by optical microscopy. The vesicles show similar X-ray diffraction patterns and differential scanning calorimetry (DSC) behavior to amorphous RTV prepared by melt-quenching crystalline RTV. Examination by polarized optical microscopy suggests that these are lyotropic liquid crystalline (LLC) assemblies. Small-angle X-ray scattering and synchrotron X-ray diffraction further support the presence of orientational order that is associated with a nematic structure. RTV self-organizes into various phases as a result of the supersaturation created in aqueous solutions. The LLC vesicles do not fuse but slowly transform to the polymorphs of RTV (in days), Form I and finally Form II. Amorphous RTV in aqueous suspension also undergoes a transformation to a mesophase of similar morphology. Transformation pathways are consistent with measured dissolution rates and solubilities: amorphous > LLC >> Form I > Form II. The dissolution and solubility of LLC is slightly lower than that of the amorphous phase and about 20 times higher than that of Form II. RTV also self-assembles at the air/water interface as indicated by the decrease in surface tension of aqueous solutions. This behavior is similar to that of amphiphilic molecules that induce LLC formation.

  20. Plasma waves and electric discharges induced by a beam from a high-latitude satellite

    International Nuclear Information System (INIS)

    Kuns, G.; Koen, G.

    1985-01-01

    Using P78-2 satellite measurements of characteristics of space probe charging in synchronous orbit are carried out. A particle beam generation system including electron and ion guns was part of the satellite equipment. Electric charge analyser placed aboard the satellite in course of electron and ion beam generation recorded plasma waves and electric discharges

  1. 3D magnetic nanostructures grown by focused electron and ion beam induced deposition

    Science.gov (United States)

    Fernandez-Pacheco, Amalio

    Three-dimensional nanomagnetism is an emerging research area, where magnetic nanostructures extend along the whole space, presenting novel functionalities not limited to the substrate plane. The development of this field could have a revolutionary impact in fields such as electronics, the Internet of Things or bio-applications. In this contribution, I will show our recent work on 3D magnetic nanostructures grown by focused electron and ion beam induced deposition. This 3D nano-printing techniques, based on the local chemical vapor deposition of a gas via the interaction with electrons and ions, makes the fabrication of complex 3D magnetic nanostructures possible. First, I will show how by exploiting different growth regimes, suspended Cobalt nanowires with modulated diameter can be patterned, with potential as domain wall devices. Afterwards, I will show recent results where the synthesis of Iron-Gallium alloys can be exploited in the field of artificial multiferroics. Moreover, we are developing novel methodologies combining physical vapor deposition and 3D nano-printing, creating Permalloy 3D nanostrips with controllable widths and lengths up to a few microns. This approach has been extended to more complex geometries by exploiting advanced simulation growth techniques combining Monte Carlo and continuum model methods. Throughout the talk, I will show the methodology we are following to characterize 3D magnetic nanostructures, by combining magneto-optical Kerr effect, scanning probe microscopy and electron and X-R magnetic imaging, and I will highlight some of the challenges and opportunities when studying these structures. I acknowledge funding from EPSRC and the Winton Foundation.

  2. Low-Temperature Electron Beam-Induced Transformations of Cesium Lead Halide Perovskite Nanocrystals

    Science.gov (United States)

    2017-01-01

    Cesium lead halide perovskite (CsPbX3, with X = Br, Cl, I) nanocrystals have been found to undergo severe modifications under the high-energy electron beam irradiation of a transmission electron microscope (80/200 keV). In particular, in our previous work, together with halogen desorption, Pb2+ ions were found to be reduced to Pb0 and then diffused to form lead nanoparticles at temperatures above −40 °C. Here, we present a detailed irradiation study of CsPbBr3 nanocrystals at temperatures below −40 °C, a range in which the diffusion of Pb0 atoms/clusters is drastically suppressed. Under these conditions, the irradiation instead induces the nucleation of randomly oriented CsBr, CsPb, and PbBr2 crystalline domains. In addition to the Br desorption, which accompanies Pb2+ reduction at all the temperatures, Br is also desorbed from the CsBr and PbBr2 domains at low temperatures, leading to a more pronounced Br loss, thus the final products are mainly composed of Cs and Pb. The overall transformation involves the creation of voids, which coalesce upon further exposure, as demonstrated in both nanosheets and nanocuboids. Our results show that although low temperatures hinder the formation of Pb nanoparticles in CsPbBr3 nanocrystals when irradiated, the nanocrystals are nevertheless unstable. Consequently, we suggest that an optimum combination of temperature range, electron energy, and dose rate needs to be carefully chosen for the characterization of halide perovskite nanocrystals to minimize both the Pb nanoparticle formation and the structural decomposition. PMID:28983524

  3. Electron beam induced deposition of silacyclohexane and dichlorosilacyclohexane: the role of dissociative ionization and dissociative electron attachment in the deposition process

    Directory of Open Access Journals (Sweden)

    Ragesh Kumar T P

    2017-11-01

    Full Text Available We present first experiments on electron beam induced deposition of silacyclohexane (SCH and dichlorosilacyclohexane (DCSCH under a focused high-energy electron beam (FEBID. We compare the deposition dynamics observed when growing pillars of high aspect ratio from these compounds and we compare the proximity effect observed for these compounds. The two precursors show similar behaviour with regards to fragmentation through dissociative ionization in the gas phase under single-collision conditions. However, while DCSCH shows appreciable cross sections with regards to dissociative electron attachment, SCH is inert with respect to this process. We discuss our deposition experiments in context of the efficiency of these different electron-induced fragmentation processes. With regards to the deposition dynamics, we observe a substantially faster growth from DCSCH and a higher saturation diameter when growing pillars with high aspect ratio. However, both compounds show similar behaviour with regards to the proximity effect. With regards to the composition of the deposits, we observe that the C/Si ratio is similar for both compounds and in both cases close to the initial molecular stoichiometry. The oxygen content in the DCSCH deposits is about double that of the SCH deposits. Only marginal chlorine is observed in the deposits of from DCSCH. We discuss these observations in context of potential approaches for Si deposition.

  4. Hypervelocity dust impact craters on photovoltaic devices imaged by ion beam induced charge

    International Nuclear Information System (INIS)

    Yang, Changyi; Wu, Yiyong; Lv, Gang; Rubanov, Sergey; Jamieson, David N.

    2015-01-01

    Hypervelocity dust has a speed of greater than 5 km/s and is a significant problem for equipment deployed in space such as satellites because of impacts that damage vulnerable components. Photovoltaic (PV) arrays are especially vulnerable because of their large surface area and the performance can be degraded owing to the disruption of the structure of the junction in the cells making up the array. Satellite PV arrays returned to Earth after service in orbit reveal a large number of craters larger than 5 μm in diameter arising from hypervelocity dust impacts. Extensive prior work has been done on the analysis of the morphology of craters in PV cells to understand the origin of the micrometeoroid that caused the crater and to study the corresponding mechanical damage to the structure of the cell. Generally, about half the craters arise from natural micrometeoroids, about one third from artificial Al-rich debris, probably from solid rocket exhausts, and the remainder from miscellaneous sources both known and unknown. However to date there has not been a microscopic study of the degradation of the electrical characteristics of PV cells exposed to hypervelocity dust impacts. Here we present an ion beam induced charge (IBIC) pilot study by a 2 MeV He microbeam of craters induced on a Hamamatsu PIN diode exposed to artificial hypervelocity Al dust from a dust accelerator. Numerous 5–30 μm diameter craters were identified and the charge collection efficiency of the crater and surrounds mapped with IBIC with bias voltages between 0 and 20 V. At highest bias, it was found the efficiency of the crater had been degraded by about 20% compared to the surrounding material. The speed distribution achieved in the Al dust accelerator was peaked at about 4 km/s compared to 11–68 km/s for dust encountered in low Earth orbit. We are able to extrapolate the charge collection efficiency degradation rate of unbiased cells in space based on our current measurements and the

  5. Hypervelocity dust impact craters on photovoltaic devices imaged by ion beam induced charge

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Changyi [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Wu, Yiyong; Lv, Gang [National Key Laboratory of Materials Behavior and Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin (China); Rubanov, Sergey [Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010 (Australia); Jamieson, David N., E-mail: d.jamieson@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia)

    2015-04-01

    Hypervelocity dust has a speed of greater than 5 km/s and is a significant problem for equipment deployed in space such as satellites because of impacts that damage vulnerable components. Photovoltaic (PV) arrays are especially vulnerable because of their large surface area and the performance can be degraded owing to the disruption of the structure of the junction in the cells making up the array. Satellite PV arrays returned to Earth after service in orbit reveal a large number of craters larger than 5 μm in diameter arising from hypervelocity dust impacts. Extensive prior work has been done on the analysis of the morphology of craters in PV cells to understand the origin of the micrometeoroid that caused the crater and to study the corresponding mechanical damage to the structure of the cell. Generally, about half the craters arise from natural micrometeoroids, about one third from artificial Al-rich debris, probably from solid rocket exhausts, and the remainder from miscellaneous sources both known and unknown. However to date there has not been a microscopic study of the degradation of the electrical characteristics of PV cells exposed to hypervelocity dust impacts. Here we present an ion beam induced charge (IBIC) pilot study by a 2 MeV He microbeam of craters induced on a Hamamatsu PIN diode exposed to artificial hypervelocity Al dust from a dust accelerator. Numerous 5–30 μm diameter craters were identified and the charge collection efficiency of the crater and surrounds mapped with IBIC with bias voltages between 0 and 20 V. At highest bias, it was found the efficiency of the crater had been degraded by about 20% compared to the surrounding material. The speed distribution achieved in the Al dust accelerator was peaked at about 4 km/s compared to 11–68 km/s for dust encountered in low Earth orbit. We are able to extrapolate the charge collection efficiency degradation rate of unbiased cells in space based on our current measurements and the

  6. Study on isoenzymes and SDS-PAGE of the electron beam induced mutant of gladiolus 'Beauty Queen'

    International Nuclear Information System (INIS)

    Zhang Zhiwei; Wang Dan; Zhang Dongxue

    2007-01-01

    In order to test the feasibility of electron beam induced mutation on Gladiolus and the effects of various doses of electron beam on flower traits, the corms of gladiolus 'Beauty Queen' were irradiated by electron beam with different doses. Flower-colour and inflorescence mutants (M1' and M2')were obtained, respectively at the doses of 40 Gy and l60 Gy. The two mutants and the parent (CK) and those irradiated with same doses (40 Gy and 160 Gy) were studied. The isozymes of POD, CAT, AMY and EST were tested, it shows that isozymes patterns of gladiolus irradiated at the doses of 40 Gy and 160 Gy a similar to CK, but the mutants' bands were added or absent compared to CK. Based on band types of isozymes, the cluster analysis was carried out and dendrogram generated using SPSS software version 11.5, it indicates that they may be divided into three groups: CK group (CK, gladiolus irradiated at the doses of 40 Gy and 160 Gy), M1' group and M2' group. The bands of protein subunit were analyzed by SDS- PAGE, it shows protein expression is obviously inhibited by electron beam irradiation. But three different protein bands were found in the two mutants, and their molecular weights were 96 kDa, 115.4 kDa, 137.2 kDa, respectively. These special proteins may have relation with regulation and control flower-color and inflorescence. The results indicate that electron beam irradiation is an effective way for inducing flower-color and flower-shape mutants. (authors)

  7. Electron beam induced deposition of silacyclohexane and dichlorosilacyclohexane : The role of dissociative ionization and dissociative electron attachment in the deposition process

    NARCIS (Netherlands)

    Ragesh Kumar, T. P.; Hari, S.; Damodaran, Krishna K.; Ingólfsson, Oddur; Hagen, C.W.

    2017-01-01

    We present first experiments on electron beam induced deposition of silacyclohexane (SCH) and dichlorosilacyclohexane (DCSCH) under a focused high-energy electron beam (FEBID). We compare the deposition dynamics observed when growing pillars of high aspect ratio from these compounds and we

  8. High energy muon induced radioactive nuclides in nickel plate and its use for 2-D muon-beam image profile

    International Nuclear Information System (INIS)

    Kurebayashi, Y.; Sakurai, H.; Takahashi, Y.; Doshita, N.; Kikuchi, S.; Tokanai, F.; Horiuchi, K.; Tajima, Y.; Oe, T.; Sato, T.; Gunji, S.; Inui, E.; Kondo, K.; Iwata, N.; Sasaki, N.; Matsuzaki, H.; Kunieda, S.

    2015-01-01

    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 –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 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

  9. Determination of the secondary energy from the electron beam with a flattening foil by computer. Percentage depth dose curve fitting using the specific higher order polynomial

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, H [Kyushu Univ., Beppu, Oita (Japan). Inst. of Balneotherapeutics

    1980-09-01

    A computer program written in FORTRAN is described for determining the secondary energy of the electron beam which passed through a flattening foil, using a time-sharing computer service. The procedure of this program is first to fit the specific higher order polynomial to the measured percentage depth dose curve. Next, the practical range is evaluated by the point of intersection R of the line tangent to the fitted curve at the inflection point P and the given dose E, as shown in Fig. 2. Finally, the secondary energy corresponded to the determined practical range can be obtained by the experimental equation (2.1) between the practial range R (g/cm/sup 2/) and the electron energy T (MeV). A graph for the fitted polynomial with the inflection points and the practical range can be plotted on a teletype machine by request of user. In order to estimate the shapes of percentage depth dose curves correspond to the electron beams of different energies, we tried to find some specific functional relationships between each coefficient of the fitted seventh-degree equation and the incident electron energies. However, exact relationships could not be obtained for irreguarity among these coefficients.

  10. Thermo-mechanical vibration analysis of a single-walled carbon nanotube embedded in an elastic medium based on higher-order shear deformation beam theory

    International Nuclear Information System (INIS)

    Ebrahimi, Farzad; Salari, Erfan

    2015-01-01

    In this study, the thermal effect on the free vibration characteristics of embedded Single-walled carbon nanotubes (SWCNTs) based on the size-dependent Reddy higher order shear deformation beam theory subjected to in-plane thermal loading is investigated by presenting a Navier-type solution and employing a semi-analytical Differential transform method (DTM) for the first time. In addition, the exact nonlocal Reddy beam theory solution presented here should be useful to engineers designing nanoelectromechanical devices. The small scale effect is considered based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton's principle, and they are solved by applying DTM. Numerical results reveal that the proposed modeling and semi-analytical approach can provide more accurate frequency results of the SWCNTs compared to analytical results and some cases in the literature. The detailed mathematical derivations are presented, and numerical investigations are performed, whereas emphasis is placed on investigating the effect of several parameters such as small-scale effects, boundary conditions, mode number, thickness ratio, temperature change, and Winkler spring modulus on the natural frequencies of the SWCNTs in detail. The vibration behavior of SWCNTs is significantly influenced by these effects. Results indicate that the inclusion of size effect results in a decrease in nanobeam stiffness and leads to a decrease in natural frequency. Numerical results are presented to serve as benchmarks for future analyses of SWCNTs.

  11. Evaluation of the oxidative stress induced by the electron beam radiation on various organs of Swiss Albino mice - in-vivo study

    International Nuclear Information System (INIS)

    Vishakh, R.; Moodithaya, Shailaja S.; Suchetha Kumari, N.; Sanjeev, Ganesh

    2014-01-01

    Radiation is one of the important threats in the modern world. Though the radiation injuries by natural means is very less common, advancement in the nuclear warfare research had increased the threat of radiation induced damage to biological system. Since years researchers are in search of a novel radio-protector, but without complete success. The reason behind may be its toxicity in higher doses. All the above research challenges lead many researchers to investigate radiation induced damage. Most of the studies had been done to investigate radiation induced damage in the lethal dose of radiation. But less work had been done to study the effect of radiation on tissues at sublethal dose. Therefore this study aims to evaluate the effect of radiation on the various organs in mice model. Swiss albino mice of 6 to 8 weeks old were divided into 2 groups i.e., Control, Radiation control with 6 mice in each group. 6 Gy sub lethal dose of electron beam radiation was used as radiation source. The liver, kidney and brain were dissected and used for biochemical analysis. The significant decrease in total antioxidant levels were observed in Liver and Kidney of irradiated mice, Glutathione levels were found to be decreased in Liver, Kidney and Brain, Glutathione S - transferase levels were found to be significantly decreased in Liver and Brain, Catalase activity was found to be decreased in Liver, Super oxide dismutase activity was found to be significantly decreased in Liver, Kidney and Brain homogenates when compared with the tissue homogenates of control group. From the results we can conclude that the liver is the most sensitive organ for the electron beam radiation induced oxidative stress when compared with Kidney and Brain. (author)

  12. In-beam study of the rotational states in actinides after alpha-induced nuclear reactions

    International Nuclear Information System (INIS)

    Hardt, K.

    1983-01-01

    In the experiments described in this thesis the ground state rotational bands of a whole series of actinide isotopes has been studied by means of α-induced nuclear reactions. The rotational bands studied in the even isotopes could be identified up to a spin of about 16 (h/2π). With this data it was now possible to establish a broad systematic of the rotational energies up to relatively high angular momenta. Also in the odd isotopes 233 U and 239 Pu it was possible to follow the ground state rotational bands up to higher spins and to compare them with predictions of the rotational model. By means of the (α,α'2n) reaction the nuclei 230 Th and especially 228 Th could by populated. (orig./HSI) [de

  13. 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.

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

    International Nuclear Information System (INIS)

    Czelusniak, C.; Palla, L.; Massi, M.; Carraresi, L.; Giuntini, L.; Re, A.; Lo Giudice, A.; Pratesi, G.; Mazzinghi, A.; Ruberto, C.; Castelli, L.

    2016-01-01

    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.

  15. Observation of the dynamics of magnetic nanoparticles induced by a focused laser beam by using dark-field microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Hai-Dong, E-mail: dhdong@scau.edu.cn [Department of Applied Physics, College of Science, South China Agricultural University, Guangzhou 510642 (China); Li, Guang-Can [Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006 (China); Li, Hai [Department of Applied Physics, College of Science, South China Agricultural University, Guangzhou 510642 (China)

    2014-08-01

    The dynamics of Fe{sub 3}O{sub 4} magnetic nanoparticles under the irradiation of a tightly focused laser beam was investigated by using a high-intensity dark-field microscopy. A depletion region of magnetic nanoparticles was found at the center of the laser beam where the dissipative force (absorption and scattering forces) dominated the dynamics of the magnetic nanoparticles. In contrast, the dynamics of magnetic nanoparticles was dominated by thermal and mass diffusions at the edge of the laser beam where the dissipative force was negligible. In addition, the transient variation in the concentration of magnetic nanoparticles was characterized by recording the transient scattering light intensity. The coefficients of thermal diffusion, mass diffusion and the Soret effect for this kind of magnetic nanoparticles were successfully extracted by using this technique. - Highlights: • The dynamics of magnetic nanoparticles induced by a focused laser beam was investigated by using dark-field microscopy. • The experimental results revealed that the dynamics of magnetic nanoparticles was dominated by different mechanisms. • A convenient technique to measure the Soret coefficient of nanoparticles was provided.

  16. Flame retardant cotton fabrics by electron beam-induced polymerization of vinyl phosphonate oligomer

    International Nuclear Information System (INIS)

    Sawai, Takeshi; Ametani, Kazuo; Enomoto, Ichiro

    1988-01-01

    Vinyl phosphonate oligomer is presently used commercially as a cellulosic flame retardant in conjugation with N-methylol acrylamide, using a persulfate catalyst and a thermal cure. This combination can also be cured at room temperature with electron beams, as can the vinyl phosphonate alone. For the textile application, fixation of flame retardants by electron beams with low energy is one of the most promising applications. For the purpose of preparing flame resistant cotton fabrics such as bed sheets and pajamas, flame retardant curing of vinyl phosphonate oligomer on cotton fabrics was examined using electron beams from a self-sealed electron beam processor and gamma rays from a 60 Co source. A joint investigation was undertaken by the Tokyo Metropolitan Textile Research Institute and Tokyo Metropolitan Isotope Research Center to determine the feasibility of curing vinyl phosphonate oligomer on the cotton fabrics for textile finishing. (author)

  17. Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

    Directory of Open Access Journals (Sweden)

    Toppi M.

    2016-01-01

    Full Text Available Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

  18. Novel Programmable Shape Memory Polystyrene Film: A Thermally Induced Beam-power Splitter

    OpenAIRE

    Peng Li; Yu Han; Wenxin Wang; Yanju Liu; Peng Jin; Jinsong Leng

    2017-01-01

    Micro/nanophotonic structures that are capable of optical wave-front shaping are implemented in optical waveguides and passive optical devices to alter the phase of the light propagating through them. The beam division directions and beam power distribution depend on the design of the micro/nanostructures. The ultimate potential of advanced micro/nanophotonic structures is limited by their structurally rigid, functional singleness and not tunable against external impact. Here, we propose a th...

  19. Investigations in thermal fields and stress fields induced by electron beam welding

    International Nuclear Information System (INIS)

    Basile, G.

    1979-12-01

    This document presents the thermal study of electron beam welding and identifies stresses and strains from welding: description of the operating principles of the electron gun and characterization of various welding parameters, examination of the temperature fields during electron beam welding development of various mathematic models and comparison with experimental results, measurement and calculation of stresses and strains in the medium plane of the welding assembly, residual stresses analysis [fr

  20. Nanoscale-Barrier Formation Induced by Low-Dose Electron-Beam Exposure in Ultrathin MoS2 Transistors.

    Science.gov (United States)

    Matsunaga, Masahiro; Higuchi, Ayaka; He, Guanchen; Yamada, Tetsushi; Krüger, Peter; Ochiai, Yuichi; Gong, Yongji; Vajtai, Robert; Ajayan, Pulickel M; Bird, Jonathan P; Aoki, Nobuyuki

    2016-10-05

    Utilizing an innovative combination of scanning-probe and spectroscopic techniques, supported by first-principles calculations, we demonstrate how electron-beam exposure of field-effect transistors, implemented from ultrathin molybdenum disulfide (MoS 2 ), may cause nanoscale structural modifications that in turn significantly modify the electrical operation of these devices. Quite surprisingly, these modifications are induced by even the relatively low electron doses used in conventional electron-beam lithography, which are found to induce compressive strain in the atomically thin MoS 2 . Likely arising from sulfur-vacancy formation in the exposed regions, the strain gives rise to a local widening of the MoS 2 bandgap, an idea that is supported both by our experiment and by the results of first-principles calculations. A nanoscale potential barrier develops at the boundary between exposed and unexposed regions and may cause extrinsic variations in the resulting electrical characteristics exhibited by the transistor. The widespread use of electron-beam lithography in nanofabrication implies that the presence of such strain must be carefully considered when seeking to harness the potential of atomically thin transistors. At the same time, this work also promises the possibility of exploiting the strain as a means to achieve "bandstructure engineering" in such devices.

  1. Study of the production of neutron-rich isotope beams issuing from fissions induced by fast neutrons

    International Nuclear Information System (INIS)

    Lau, Ch.

    2000-01-01

    This work is a contribution to the PARRNe project (production of radioactive neutron-rich isotopes). This project is based on the fission fragments coming from the fission of 238-uranium induced by fast neutrons. The fast neutron flux is produced by the collisions of deutons in a converter. Thick targets of uranium carbide and liquid uranium targets have been designed in order to allow a quick release of fission fragments. A device, able to trap on a cryogenic thimble rare gas released by the target, has allowed the production of radioactive nuclei whose half-life is about 1 second. This installation has been settled to different deuton accelerators in the framework of the European collaboration SPIRAL-2. A calibration experiment has proved the feasibility of fixing an ISOL-type isotope separator to a 15 MV tandem accelerator, this installation can provide 500 nA deutons beams whose energy is 26 MeV and be a valuable tool for studying fast-neutron induced fission. Zinc, krypton, rubidium, cadmium, iodine, xenon and cesium beams have been produced in this installation. The most intense beams reach 10000 nuclei by micro-coulomb for 26 MeV deutons. An extra gain of 2 magnitude orders can be obtained by using a more specific ion source and by increasing the thickness of the target. Another extra gain of 2 magnitude orders involves 100 MeV deutons

  2. Effect of an ultrafast laser induced plasma on a relativistic electron beam to determine temporal overlap in pump–probe experiments

    Energy Technology Data Exchange (ETDEWEB)

    Scoby, Cheyne M., E-mail: scoby@physics.ucla.edu [UCLA Department of Physics, 475 Portola Plaza, Los Angeles, CA 90095-1547 (United States); Li, R.K.; Musumeci, P. [UCLA Department of Physics, 475 Portola Plaza, Los Angeles, CA 90095-1547 (United States)

    2013-04-15

    In this paper we report on a simple and robust method to measure the absolute temporal overlap of the laser and the electron beam at the sample based on the effect of a laser induced plasma on the electron beam transverse distribution, successfully extending a similar method from keV to MeV electron beams. By pumping a standard copper TEM grid to form the plasma, we gain timing information independent of the sample under study. In experiments discussed here the optical delay to achieve temporal overlap between the pump electron beam and probe laser can be determined with ∼1ps precision.

  3. Effect of an ultrafast laser induced plasma on a relativistic electron beam to determine temporal overlap in pump–probe experiments

    International Nuclear Information System (INIS)

    Scoby, Cheyne M.; Li, R.K.; Musumeci, P.

    2013-01-01

    In this paper we report on a simple and robust method to measure the absolute temporal overlap of the laser and the electron beam at the sample based on the effect of a laser induced plasma on the electron beam transverse distribution, successfully extending a similar method from keV to MeV electron beams. By pumping a standard copper TEM grid to form the plasma, we gain timing information independent of the sample under study. In experiments discussed here the optical delay to achieve temporal overlap between the pump electron beam and probe laser can be determined with ∼1ps precision

  4. Electron beam induced modifications in flexible biaxially oriented polyethylene terephthalate sheets: Improved mechanical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, N. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Koiry, S.P. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Singh, A., E-mail: asb_barc@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Tillu, A.R. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Jha, P.; Samanta, S.; Debnath, A.K. [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Aswal, D.K., E-mail: dkaswal@yahoo.com [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Mondal, R.K. [Radiation Technology Development Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India); Acharya, S.; Mittal, K.C. [Accelerator & Pulse Power Division, Bhabha Atomic Research Centre, Mumbai, 400 085 (India)

    2017-03-01

    In the present work, we have studied the effects of electron beam irradiation (with dose ranging from 2 to 32 kGy) on mechanical and electrical properties of biaxially oriented polyethylene terephthalate (BOPET) sheets. The sol-gel analysis, Fourier transformation infra-red (FTIR), X-ray photoelectron spectroscopy (XPS) characterizations of the irradiated BOPET sheets suggest partial cross-linking of PET chains through the diethylene glycol (DEG). The mechanical properties of BOPET, such as, tensile strength, Young's modulus and electrical resistivity shows improvement with increasing dose and saturate for doses >10 kGy. The improved mechanical properties and high electrical resistivity of electron beam modified BOPET sheets may have additional advantages in applications, such as, packaging materials for food irradiation, medical product sterilization and electronic industries. - Graphical abstract: Irradiation of BOPET by electron beam leads to the formation of diethylene glycol that crosslink's the PET chains, resulting in improved mechanical properties and enhanced electrical resistivity. - Highlights: • BOPET exhibit improved tensile strength/Young's modulus after e-beam exposure. • Electrical resistivity of BOPET increases after e-beam exposure. • Cross-linking of PET chains through diethylene glycol was observed after e-beam exposure.

  5. Electron-beam induced structural and function change of microbial peroxiredoxin

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S. H.; An, B. C.; Lee, S. S.; Lee, E. M.; Chung, B. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-03-15

    Pseudomonas aerogenes peroxiredoxin (PaPrx) has dual functions acting as thioredoxin (Trx)-dependent peroxidase and molecular chaperone. The function of PaPrx is controlled by its structural status. In this study, we examined the effect of electron beam on structural modification related to chaperone activity. When irradiated electron beam at 1 kGy, the structural and functional changes of PaPrx were initiated. The enhanced chaperone activity was increased about 3- 40 4-fold at 2 kGy compared with non-irradiated, while the peroxidase activity was decreased. We also investigated the influence of the electron beam on protein physical property factors such as hydrophobicity and secondary structure. The exposure of hydrophobic domains reached a peak at 2 kGy of electron beam and then dose-dependently decreased with increasing electron beam irradiation. In addition, the electron beam irradiated PaPrx significantly increased exposure of {beta}-sheet and random coil elements on the protein surface whereas exposure of {alpha}-helix and turn elements was decreased. Our results suggest that highly enhanced chaperone activity could be applied to use in bio-engineering system and various industrial applications.

  6. Electron-beam induced structural and function change of microbial peroxiredoxin

    International Nuclear Information System (INIS)

    Hong, S. H.; An, B. C.; Lee, S. S.; Lee, E. M.; Chung, B. Y.

    2012-01-01

    Pseudomonas aerogenes peroxiredoxin (PaPrx) has dual functions acting as thioredoxin (Trx)-dependent peroxidase and molecular chaperone. The function of PaPrx is controlled by its structural status. In this study, we examined the effect of electron beam on structural modification related to chaperone activity. When irradiated electron beam at 1 kGy, the structural and functional changes of PaPrx were initiated. The enhanced chaperone activity was increased about 3- 40 4-fold at 2 kGy compared with non-irradiated, while the peroxidase activity was decreased. We also investigated the influence of the electron beam on protein physical property factors such as hydrophobicity and secondary structure. The exposure of hydrophobic domains reached a peak at 2 kGy of electron beam and then dose-dependently decreased with increasing electron beam irradiation. In addition, the electron beam irradiated PaPrx significantly increased exposure of β-sheet and random coil elements on the protein surface whereas exposure of α-helix and turn elements was decreased. Our results suggest that highly enhanced chaperone activity could be applied to use in bio-engineering system and various industrial applications

  7. Thon rings from amorphous ice and implications of beam-induced Brownian motion in single particle electron cryo-microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McMullan, G., E-mail: gm2@mrc-lmb.cam.ac.uk; Vinothkumar, K.R.; Henderson, R.

    2015-11-15

    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{sup 2} for every incident 300 keV e{sup −}/Å{sup 2}. The induced motion leads to an optimal exposure with 300 keV electrons of 4.0 e{sup −}/Å{sup 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. - Highlights: • Thon rings can be seen from amorphous ice. • Radiation damage to amorphous ice randomly displaces water molecules. • Each incident 300 keV e{sup −}/Å{sup 2} displaces water molecules on average by ∼1 Å. • Macromolecules embedded in amorphous ice undergo beam induced Brownian motion.

  8. A new Arabidopsis mutant induced by ion beams affects flavonoid synthesis with spotted pigmentation in testa

    International Nuclear Information System (INIS)

    Tanaka, A.; Tano, S.; Chantes, T.; Yokota, Y.; Shikazono, N.; Watanabe, H.

    1997-01-01

    A new stable mutant of Arabidopsis thaliana with a spotted pigment in the seed coat, named anthocyanin spotted testa (ast), was induced by carbon ion irradiation. The spotted pigmentation of ast mutant was observed in immature seeds from 1-2 days after flowering (DAF), at the integument of the ovule, and spread as the seed coat formed. Anthocyanin accumulation was about 6 times higher in ast mutant than in the wild-type at 6 DAF of the immature seeds, but was almost the same in mature dry seeds. A higher anthocyanin accumulation was not observed in the seedlings, leaves or floral buds of ast mutant compared with the wild-type, which suggests that a high accumulation of anthocyanins is specific to the seed coat of the immature ast seeds. Reciprocal crosses between ast mutant and the wild-type indicated that ast is a single recessive gene mutation and segregates as a delayed inheritance. The results of crossing with tt7 and ttg mutants also confirmed that the AST gene is probably a regulatory locus that controls flavonoid biosynthesis. A mapping analysis revealed that the gene is located on chromosome I and is closely linked to the SSLP DNA marker nga280 with a distance of 3.2 cM. AST has been registered as a new mutant of Arabidopsis

  9. Dopamine mediated iron release from ferritin is enhanced at higher temperatures: Possible implications for fever-induced Parkinson's disease

    International Nuclear Information System (INIS)

    Babincova, Melania; Babinec, Peter

    2005-01-01

    A new molecular mechanism is proposed to explain the pathogenesis of fever-induced Parkinson's disease. This proposal is based on dopamine and 6-hydroxydopamine-mediated free iron release from ferritin magnetic nanoparticles, which is enhanced at higher temperatures, and which may lead to substantial peroxidation and injury of lipid biomembranes of the substantia nigra in the brain

  10. Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

    2005-01-01

    Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

  11. Development of a PIXE (Particle Induced X-ray Emission) analysis device using an extracted proton beam

    International Nuclear Information System (INIS)

    Saidi, A.

    1989-01-01

    The experimental device described allows the extention of the PIXE (Particle Induced X-ray Emission) method to the analysis, by means of proton beams, of solid or liquid samples, which can not be analyzed under vacuum conditions. The homogeneity of the surfaces to be analysed and elements (in the atmosphere) which absorb X-rays must be taken into account. Liquid samples do not need special care. The results show that: at high energies, the extracted beam sensibility is of the same order of magnitude as those obtained under vacuum; at low energies, the performance under vacuum conditions is better. The particles energy losses, at the exit membrane and in the outer atmosphere, decrease the X-rays production efficiency [fr

  12. Superresolution beams

    CSIR Research Space (South Africa)

    Ngcobo, S

    2011-11-01

    Full Text Available The transformation of a Gaussian beam (GB) into a symmetrical higher order TEMp0 Laguerre Gaussian beam (LGB) intensity distribution of which is further rectified and transformed into a Gaussian intensity distribution in the plane of a converging...

  13. Beam-Beam Effects

    International Nuclear Information System (INIS)

    Herr, W; Pieloni, T

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities

  14. Study on the proton-induced X-ray emission(PIXE) using external proton beam

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, M. Y.; Yoon, J. C.; Park, K. J. [Seoul Natioanl University, Seoul (Korea, Republic of)

    2008-04-15

    We intend to develop a system that can extract a proton beam into air for a qualitative, and quantitative PIXE analysis up to ppm(percent per million) composition. When such an R and D is accomplished, first it is possible to get equipped with a system for PIXE and PIGmE, second, it is possible to contribute to an academic progress by the study for physical properties of matter through an nuclear science methods when the comparison between the measurement and the calculated quantities, and third, it is possible to contribute to a multi-disciplinary researches by the measurements of the samples for which it is hard to get the SRM for the samples. We intend to develop methods to measure the beam current for an air-borne proton beam, and to minimize the energy and current loss of the beam. We intend to acquire a set of PIXE data for rare-earth metals and transient metals, to form a basic database for the analysis for various samples for which it is hard to get the SRM. Developed PIXE beamline can extract the beam diameter up to 5mm, and beam intensity in the range 0.5nA to 10nA variable. sustaining the vacuum better than 10{sup -6} mtorr. Necessary detection system and methodology are complete. As the application of the present research achievements, we studied the analysis of aerosol composition, the appraisal of the cultural heritages, and a feasibility study for a proton beam writing. It is expected to become possible to analyse the compositions of the gems, the elemental compositions of the food, the discrimination of the traditional ink and the modern ink on the documents, the evaluation of the documents by the analysis of the elemental composition of the stamps, The analysis of the paper with respect to the date and the quality, the analysis of the color, and the core bored samples

  15. Concrete cover cracking with reinforcement corrosion of RC beam during chloride-induced corrosion process

    International Nuclear Information System (INIS)

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2010-01-01

    This paper deals with the evolution of the corrosion pattern based on two beams corroded by 14 years (beam B1CL1) and 23 years (beam B2CL1) of conservation in a chloride environment. The experimental results indicate that, at the cracking initiation stage and the first stage of cracking propagation, localized corrosion due to chloride ingress is the predominant corrosion pattern and pitting corrosion is the main factor that influences the cracking process. As corrosion cracking increases, general corrosion develops rapidly and gradually becomes predominant in the second stage of cracking propagation. A comparison between existing models and experimental results illustrates that, although Vidal et al.'s model can better predict the reinforcement corrosion of beam B1CL1 under localized corrosion, it cannot predict the corrosion of beam B2CL1 under general corrosion. Also, Rodriguez's model, derived from the general corrosion due to electrically accelerated corrosion experiments, cannot match natural chloride corrosion irrespective of whether corrosion is localized or general. Thus, for natural general corrosion in the second stage of cracking propagation, a new model based on the parameter of average steel cross-section loss is put forward to predict steel corrosion from corrosion cracking.

  16. Investigation of the depth profile of ion beam induced nanopatterns on Si with simultaneous metal incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, Behnam; Arezki, Bahia; Biermanns, Andreas; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Siegen (Germany); Cornejo, Marina; Frost, Frank [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2011-07-01

    Ion beam sputtering of semiconductor surfaces can modify the surface and produce a diversity of surface topographies such as periodic ripples or dot structures depended on sputtering parameters. Well ordered nanostructured surfaces have widely technological applications. Recent experiments have shown that the incorporation of metallic impurity atoms during the sputtering process plays a crucial role in pattern formation on the surfaces. These findings offer a new degree of freedom to control pattern formation. In this contribution we report on surface patterning due to Kr ion beam erosion on silicon surfaces with simultaneous Fe and Cr incorporation. We used X-ray reflectivity (XRR) to determine the depth profiles of metal ions as function of ion beam divergence angles and the mean incidence angle of the ions with respect to the surface normal. Depth profiles are correlated with degree of pattern formation determined by AFM. We show that the mean penetration depth and concentration of metal ions depends on the divergence angle of Kr beam provided by Kaufman source which supports the assumption that metal ions are created due to parasitic interaction of the Kr beam with the steel plate lining. The evaluated depth profile by XRR is in good agreement with SIMS and RBS results.

  17. 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...

  18. Simulation-aided investigation of beam hardening induced errors in CT dimensional metrology

    DEFF Research Database (Denmark)

    Tan, Ye; Kiekens, Kim; Welkenhuyzen, Frank

    2014-01-01

    are mutually correlated, it remains challenging to interpret measurement results and to identify the distinct error sources. Since simulations allow isolating the different affecting factors, they form a useful complement to experimental investigations. Dewulf et al (2012 CIRP Ann. Manuf. Technol. 61 495......–8) investigated the influence of beam hardening correction parameters on the diameter of a calibrated steel pin in different experimental set-ups. It was clearly shown that an inappropriate beam hardening correction can result in significant dimensional errors. This paper confirms these results using simulations...... of a pin surrounded by a stepped cylinder: a clear discontinuity in the measured diameter of the inner pin is observed where it enters the surrounding material. The results are expanded with an investigation of the beam hardening effect on the measurement results for both inner and outer diameters...

  19. Protective role of Carica papaya (Linn.) in electron beam radiation induced hematological and cytogenetic damages in Swiss albino mice

    International Nuclear Information System (INIS)

    Yogish Somayaji, T.; Suchetha Kumari, N.

    2014-01-01

    Carica papaya (Linn.) is known to possess various biomedical applications. It has remarkable antioxidant properties. The main objective of the study was to evaluate the leaf extracts of Carica papaya (Linn.) on hematologic and cytogenetic changes occurring due to irradiation of mice to sub-lethal doses of Electron Beam Radiation (EBR). Analysis of hematological changes occurring due to irradiation of mice to sub-lethal doses of EBR, and the effects of Carica papaya (Linn.) extract on the same. The Assessment of hematopoietic stress by spleen colony forming unit and spleen body weight index. The analysis of cell proliferation and immunomodulation with response to the effects of Carica papaya (Linn.) extract by estimation of IL-6. The estimation of serum total antioxidants, lipid peroxidation and analyzing the activities of enzymes like SOD, ALP, and AST. Male Swiss albino mice were fed orally with papaya aqueous leaf extract for 15 days. They were irradiated with a whole body dose of 6 Gy Electron Beam radiation. The mice were dissected for liver, kidney, bone marrow, spleen and brain. The hematological studies were done using blood cell count in an automated cell counter. The biochemical estimations like urea, creatinine, SGOT, SGPT, Total Protein, Albumin, Bilirubin were done using the serum and homogenates. The total antioxidant capacity, the antioxidant enzymes were estimated. The Interleukin-6 levels were estimated in serum to assess immune modulation. The results show a decrease in the hematological parameters in radiated animals. The papaya treated groups have shown modulation in the hematological parameters. The extract has also reduced the suppression of the bone marrow induced by radiation. The radiation induced liver damage is also reduced in papaya treated groups. The aqueous extract of Carica papaya (Linn.) has shown protective effects in electron beam radiation induced tissue damages in Swiss Albino mice (author)

  20. RBEs and cytogenetic hereditary effects induced by neutron beams in mice

    International Nuclear Information System (INIS)

    Du Zeji; Li Yanyi; Liu Degui

    1994-01-01

    The RBEs and cytogenetic hereditary effects of different dose of neutron beams on chromosome aberrations and micronuclei of bone marrow cells in mice were observed. The results indicated that micronuclei frequency of occurrence and chromosome aberration frequency caused by neutrons increased with doses. The relationship was feasible to Y aD n . The lower energy of neutrons had the smaller value of RBE. RBE determined by CSACR were larger than that by MNCF. RBEs decreased with increasing of neutron doses, especially within the low range of doses. There was a linear relationship between CSACR and MNCF caused by neutron beams and γ-ray

  1. Tuning the shape and damage in ion-beam induced ripples on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Biermanns, Andreas; Pietsch, Ullrich [Universitaet Siegen, Festkoerperphysik, 57068 Siegen (Germany); Hanisch, Antje; Grenzer, Joerg [Helmholtz-Zentrum Dresden-Rossendorf, Institut fuer Ionenstrahlphysik und Materialforschung, P.O. Box 510119, 01314 Dresden (Germany); Metzger, Till Hartmut [ESRF, 6 rue Jules Horowitz, BP220, 38043 Grenoble Cedex (France)

    2011-11-15

    We investigate the influence of ion beam parameters on the ripple formation on Si(001) surfaces after bombardment with Xe{sup +} ions of 25 keV kinetic energy using a scanning ion beam system. By combining grazing incidence X-ray diffraction, small angle scattering and X-ray reflectivity, we show that during ion irradiation with 70 off-normal angle of incidence, changing the size of the irradiated area leads to an increased number of defects at the interface towards crystalline material. At 65 angle of incidence, the ripple amplitude grows. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Fabrication of FeSi and Fe{sub 3}Si compounds by electron beam induced mixing of [Fe/Si]{sub 2} and [Fe{sub 3}/Si]{sub 2} multilayers grown by focused electron beam induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Porrati, F.; Sachser, R.; Huth, M. [Physikalisches Institut, Goethe-Universität, Max-von-Laue-Str. 1, D-60438 Frankfurt am Main (Germany); Gazzadi, G. C. [S3 Center, Nanoscience Institute-CNR, Via Campi 213/a, 41125 Modena (Italy); Frabboni, S. [S3 Center, Nanoscience Institute-CNR, Via Campi 213/a, 41125 Modena (Italy); FIM Department, University of Modena and Reggio Emilia, Via G. Campi 213/a, 41125 Modena (Italy)

    2016-06-21

    Fe-Si binary compounds have been fabricated by focused electron beam induced deposition by the alternating use of iron pentacarbonyl, Fe(CO){sub 5}, and neopentasilane, Si{sub 5}H{sub 12} as precursor gases. The fabrication procedure consisted in preparing multilayer structures which were treated by low-energy electron irradiation and annealing to induce atomic species intermixing. In this way, we are able to fabricate FeSi and Fe{sub 3}Si binary compounds from [Fe/Si]{sub 2} and [Fe{sub 3}/Si]{sub 2} multilayers, as shown by transmission electron microscopy investigations. This fabrication procedure is useful to obtain nanostructured binary alloys from precursors which compete for adsorption sites during growth and, therefore, cannot be used simultaneously.

  3. Preparation of New Adsorbent Containing Hydroxamic Acid Groups by Electron Beam-Induced Grafting for Metal Ion Adsorption

    International Nuclear Information System (INIS)

    Suwanmala, Phiriyatorn; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

    2007-08-01

    Full text: A new adsorbent containing hydroxamic acid groups was synthesized by electron beam-induced graft copolymerization of methyl acrylate (MA) onto nonwoven fabric composed of polyethylene-coated polypropylene fiber. Conversion of ester groups of the grafted copolymer into the hydroxamic groups was performed by treatment with an alkaline solution of hydroxylamine (HA). Adsorbent containing hydroxamic acid groups can adsorb 99% of UO2 2+ , 98% of V5+, 97% of Pb2+ and 96% of Al3+ at pH, 5, 4, 6, and 4, respectively, after coming into contact with 100 ppb metal solution for 24 h

  4. A three-dimensional relaxation model for calculation of atomic mixing and topography changes induces by ion beams

    International Nuclear Information System (INIS)

    Collins, R.; Perez-Martin, A.M.C.; Dominguez-Vazquez, J.; Jimenez-Rodriguez, J.J.

    1994-01-01

    A simple model for three-dimensional material relaxation associated with atomic mixing is presented. The relaxation of the solid to accommodate the extra effective displacement volume Ω of an implanted or relocated atom is modelled by treating the surrounding solid as an incompressible medium. This leads to a tractable general formalism which can be used to predict implant distribution and changes in surface topography induced by ion beams, both in monatomic and multicomponent targets. The two-component case is discussed in detail. (orig.)

  5. Auger electron spectroscopy analysis of high metal content micro-structures grown by electron beam induced deposition

    International Nuclear Information System (INIS)

    Cicoira, F.; Hoffmann, P.; Olsson, C.O.A.; Xanthopoulos, N.; Mathieu, H.J.; Doppelt, P.

    2005-01-01

    An auger electron spectroscopy study was carried out on Rh-containing micro-structures grown by electron beam induced deposition (EBID) of the iso-structural and iso-electronic precursors [RhCl(PF 3 ) 2 ] 2 and [RhCl(CO) 2 ] 2 . A material containing between 55 and 60 at.% Rh was obtained from both precursors. The chemical composition of structures grown from the two different precursors indicates a similar decomposition mechanism. Deposits grown from [RhCl(PF 3 ) 2 ] 2 showed a chemical composition independent of electron energy and electron dose in the investigated range of conditions

  6. Higher sensitivity to cadmium induced cell death of basal forebrain cholinergic neurons: A cholinesterase dependent mechanism

    International Nuclear Information System (INIS)

    Del Pino, Javier; Zeballos, Garbriela; Anadon, María José; Capo, Miguel Andrés; Díaz, María Jesús; García, Jimena; Frejo, María Teresa

    2014-01-01

    Cadmium is an environmental pollutant, which is a cause of concern because it can be greatly concentrated in the organism causing severe damage to a variety of organs including the nervous system which is one of the most affected. Cadmium has been reported to produce learning and memory dysfunctions and Alzheimer like symptoms, though the mechanism is unknown. On the other hand, cholinergic system in central nervous system (CNS) is implicated on learning and memory regulation, and it has been reported that cadmium can affect cholinergic transmission and it can also induce selective toxicity on cholinergic system at peripheral level, producing cholinergic neurons loss, which may explain cadmium effects on learning and memory processes if produced on central level. The present study is aimed at researching the selective neurotoxicity induced by cadmium on cholinergic system in CNS. For this purpose we evaluated, in basal forebrain region, the cadmium toxic effects on neuronal viability and the cholinergic mechanisms related to it on NS56 cholinergic mourine septal cell line. This study proves that cadmium induces a more pronounced, but not selective, cell death on acetylcholinesterase (AChE) on cholinergic neurons. Moreover, MTT and LDH assays showed a dose dependent decrease of cell viability in NS56 cells. The ACh treatment of SN56 cells did not revert cell viability reduction induced by cadmium, but siRNA transfection against AChE partially reduced it. Our present results provide new understanding of the mechanisms contributing to the harmful effects of cadmium on the function and viability of neurons, and the possible relevance of cadmium in the pathogenesis of neurodegenerative diseases

  7. Development of a Higher Order Laminate Theory for Modeling Composites with Induced Strain Actuators

    Science.gov (United States)

    Chattopadhyay, Aditi; Seeley, Charles E.

    1996-01-01

    A refined higher order plate theory is developed to investigate the actuation mechanism of piezoelectric materials surface bonded or embedded in composite laminates. The current analysis uses a displacement field which accurately accounts for transverse shear stresses. Some higher order terms are identified by using the conditions that shear stresses vanish at all free surfaces. Therefore, all boundary conditions for displacements and stresses are satisfied in the present theory. The analysis is implemented using the finite element method which provides a convenient means to construct a numerical solution due to the discrete nature of the actuators. The higher order theory is computationally less expensive than a full three dimensional analysis. The theory is also shown to agree well with published experimental results. Numerical examples are presented for composite plates with thicknesses ranging from thin to very thick.

  8. Beam-induced back-streaming electron suppression analysis for an accelerator type neutron generator designed for 40Ar/39Ar geochronology.

    Science.gov (United States)

    Waltz, Cory; Ayllon, Mauricio; Becker, Tim; Bernstein, Lee; Leung, Ka-Ngo; Kirsch, Leo; Renne, Paul; Bibber, Karl Van

    2017-07-01

    A facility based on a next-generation, high-flux D-D neutron generator has been commissioned and it is now operational at the University of California, Berkeley. The current generator designed for 40 Ar/ 39 Ar dating of geological materials produces nearly monoenergetic 2.45MeV neutrons at outputs of 10 8 n/s. The narrow energy range is advantageous relative to the 235 U fission spectrum neutrons due to (i) reduced 39 Ar recoil energy, (ii) minimized production of interfering argon isotopes from K, Ca, and Cl, and (iii) reduced total activity for radiological safety and waste generation. Calculations provided show that future conditioning at higher currents and voltages will allow for a neutron output of over 10 10 n/s, which is a necessary requirement for production of measurable quantities of 39 Ar through the reaction 39 K(n,p) 39 Ar. A significant problem encountered with increasing deuteron current was beam-induced electron backstreaming. Two methods of suppressing secondary electrons resulting from the deuterium beam striking the target were tested: the application of static electric and magnetic fields. Computational simulations of both techniques were done using a finite element analysis in COMSOL Multiphysics ® . Experimental tests verified these simulations. The most reliable suppression was achieved via the implementation of an electrostatic shroud with a voltage offset of -800V relative to the target. Copyright © 2017. Published by Elsevier Ltd.

  9. Higher-order geodesic deviation for charged particles and resonance induced by gravitational waves

    Science.gov (United States)

    Heydari-Fard, M.; Hasani, S. N.

    We generalize the higher-order geodesic deviation for the structure-less test particles to the higher-order geodesic deviation equations of the charged particles [R. Kerner, J. W. van Holten and R. Colistete Jr., Class. Quantum Grav. 18 (2001) 4725]. By solving these equations for charged particles moving in a constant magnetic field in the spacetime of a gravitational wave, we show for both cases when the gravitational wave is parallel and perpendicular to the constant magnetic field, a magnetic resonance appears at wg = Ω. This feature might be useful to detect the gravitational wave with high frequencies.

  10. Beam-induced radiation in the compact muon solenoid tracker at the ...

    Indian Academy of Sciences (India)

    This will lead to very high particle fluxes and energy deposition in detector components which may cause .... MARS was developed 30 years ago, for fast inclusive as ... fluences beyond 1 × 1015 cm−2 for minimum ionizing protons [6]. So we expect ... Generically speaking MIB originate from losses of the beam particles [7] ...

  11. Angular Dependence of the Ion-Induced Secondary Electron Emission for He+ and Ga+ Beams

    NARCIS (Netherlands)

    Castaldo, V.; Withagen, J.; Hagen, C.; Kruit, P.; Van Veldhoven, E.

    2011-01-01

    In recent years, novel ion sources have been designed and developed that have enabled focused ion beam machines to go beyond their use as nano-fabrication tools. Secondary electrons are usually taken to form images, for their yield is high and strongly dependent on the surface characteristics, in

  12. Mega-electron-volt ion beam induced anisotropic plasmon resonance of silver nanocrystals in glass

    NARCIS (Netherlands)

    Penninkhof, JJ; Polman, A; Sweatlock, LA; Maier, SA; Atwater, HA; Vredenberg, AM; Kooi, BJ; Sweatlock, Luke A.; Maier, Stefan A.

    2003-01-01

    30 MeV Si ion beam irradiation of silica glass containing Ag nanocrystals causes alignment of Ag nanocrystals in arrays along the ion tracks. Optical transmission measurements show a large splitting of the surface plasmon resonance bands for polarizations longitudinal and transversal to the arrays.

  13. Large flexibility of high aspect ratio carbon nanostructures fabricated by electron-beam-induced deposition

    Energy Technology Data Exchange (ETDEWEB)

    Beard, J D; Gordeev, S N, E-mail: jdb28@bath.ac.uk [Department of Physics, University of Bath, Bath BA2 7AY (United Kingdom)

    2010-11-26

    The mechanical properties of free-standing electron beam deposited amorphous carbon structures have been studied using atomic force microscopy. The fabricated carbon blades are found to be extraordinarily flexible, capable of undergoing vertical deflection up to {approx} 75% of their total length without inelastic deformation. The elastic bending modulus of these structures was calculated to be 28 {+-} 10 GPa.

  14. Shock loads induced on metal structures by LHC proton beams: modelling of thermo-mechanical effects

    CERN Document Server

    Peroni, L; Dallocchio, A; Bertarelli, A

    2011-01-01

    In this work, the numerical simulations of the LHC high energy particle beam impact against a metal structure are performed using the commercial FEM code LS-DYNA. The evaluation of thermal loads on the hit material is performed using a statistical code, called FLUKA, based on the Monte-Carlo method, which returns an energy map on a particular geometry (taking into account all the particles in the cascade generated by the interaction between the proton beam and the target). The FLUKA results are then used as input for thermo-structural studies. The first step of this work is the validation of the numerical procedure on a simple geometry for two different materials (copper and tungsten) and constitutive material models. In particular, the high energy particle impact is examined on a facially irradiated cylindrical bar: the beam hits the component directly on the centre of the basis. Then the final step is the study of the impact on a real structure with an energy beam of 5 TeV (the next target in the energy val...

  15. Modelling of pulsed electron beam induced graphite ablation: Sublimation versus melting

    Science.gov (United States)

    Ali, Muddassir; Henda, Redhouane

    2017-12-01

    Pulsed electron beam ablation (PEBA) has recently emerged as a very promising technique for the deposition of thin films with superior properties. Interaction of the pulsed electron beam with the target material is a complex process, which consists of heating, phase transition, and erosion of a small portion from the target surface. Ablation can be significantly affected by the nature of thermal phenomena taking place at the target surface, with subsequent bearing on the properties, stoichiometry and structure of deposited thin films. A two stage, one-dimensional heat conduction model is presented to describe two different thermal phenomena accounting for interaction of a graphite target with a polyenergetic electron beam. In the first instance, the thermal phenomena are comprised of heating, melting and vaporization of the target surface, while in the second instance the thermal phenomena are described in terms of heating and sublimation of the graphite surface. In this work, the electron beam delivers intense electron pulses of ∼100 ns with energies up to 16 keV and an electric current of ∼400 A to a graphite target. The temperature distribution, surface recession velocity, ablated mass per unit area, and ablation depth for the graphite target are numerically simulated by the finite element method for each case. Based on calculation findings and available experimental data, ablation appears to occur mainly in the regime of melting and vaporization from the surface.

  16. 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

  17. Higher incidence of Epstein-Barr virus-induced lymphocyte transformation in multiple sclerosis

    DEFF Research Database (Denmark)

    Tørring, Caroline Winther; Andreasen, Charlotte; Gehr, Nikolaj

    2014-01-01

    Objectives Epstein–Barr virus (EBV) infection is associated with multiple sclerosis (MS), and EBV may transform lymphoblastoid cell lines more frequently in MS patients than controls, but it is not clear whether this reflects a higher viral load or an enhanced ability to reactivate EBV. Material...

  18. Relativistically Induced Transparency Acceleration (RITA) - laser-plasma accelerated quasi-monoenergetic GeV ion-beams with existing lasers?

    Science.gov (United States)

    Sahai, Aakash A.

    2013-10-01

    Laser-plasma ion accelerators have the potential to produce beams with unprecedented characteristics of ultra-short bunch lengths (100s of fs) and high bunch-charge (1010 particles) over acceleration length of about 100 microns. However, creating and controlling mono-energetic bunches while accelerating to high-energies has been a challenge. If high-energy mono-energetic beams can be demonstrated with minimal post-processing, laser (ω0)-plasma (ωpe) ion accelerators may be used in a wide-range of applications such as cancer hadron-therapy, medical isotope production, neutron generation, radiography and high-energy density science. Here we demonstrate using analysis and simulations that using relativistic intensity laser-pulses and heavy-ion (Mi ×me) targets doped with a proton (or light-ion) species (mp ×me) of trace density (at least an order of magnitude below the cold critical density) we can scale up the energy of quasi-mono-energetically accelerated proton (or light-ion) beams while controlling their energy, charge and energy spectrum. This is achieved by controlling the laser propagation into an overdense (ω0 RITA). Desired proton or light-ion energies can be achieved by controlling the velocity of the snowplow, which is shown to scale inversely with the rise-time of the laser (higher energies for shorter pulses) and directly with the scale-length of the plasma density gradient. Similar acceleration can be produced by controlling the increase of the laser frequency (Chirp Induced Transparency Acceleration, ChITA). Work supported by the National Science Foundation under NSF- PHY-0936278. Also, NSF-PHY-0936266 and NSF-PHY-0903039; the US Department of Energy under DEFC02-07ER41500, DE- FG02-92ER40727 and DE-FG52-09NA29552.

  19. Studies of the beam-beam interaction for the LHC

    International Nuclear Information System (INIS)

    Krishnagopal, S.; Furman, M.A.; Turner, W.C.

    1999-01-01

    The authors have used the beam-beam simulation code CBI to study the beam-beam interaction for the LHC. We find that for nominal LHC parameters, and assuming only one bunch per beam, there are no collective (coherent) beam-beam instabilities. We have investigated the effect of sweeping one of the beams around the other (a procedure that could be used as a diagnostic for head-on beam-beam collisions). We find that this does not cause any problems at the nominal current, though at higher currents there can be beam blow-up and collective beam motion. consequence of quadrupole collective effects

  20. Protective effect of Asparagus racemosus root extract against lethal total - body electron beam radiation induced damage in Swiss albino mice

    International Nuclear Information System (INIS)

    Sharmila, K.P.; Bhandary, B. Satheesh Kumar; Suchetha Kumari, N.; Bhat, Vadish S.; Shetty, Jayaram; Peter, Alex John; Jose, Jerish M.; Fernandes, Ronald

    2016-01-01

    To investigate the protective effect of Asparagus Racemosus Root ethanolic extract (ARE) in Swiss albino mice against acute lethal total - body Electron beam irradiation. Swiss Albino mice were used for the assessment of radiation induced sickness and 30 day survival analysis. Survival studies were determined using the Kaplan-Meier survival curves. The maximum survival was observed in the experimental mice pretreated with 200 mg/kg.b.wt. of ARE which also reduced the radiation sickness characteristics. This dose was considered as an optimal dose for radioprotection. Treatment of mice with ARE before irradiation delayed the onset of mortality as compared with the untreated irradiated controls. Present findings demonstrate the potential of ARE in mitigating radiation-induced mortality, which may be attributed to its free radical scavenging and increased antioxidant potential

  1. Ion species dependence of the implantation-induced defects in ZnO studied by a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Naramoto, H.

    2007-01-01

    In this work, we implanted B + , O + , Al + , and P + ions into ZnO with energy of 50-380 keV and total doses of 4 x 10 15 cm -2 for each ion. The implantation-induced defects and their thermal recovery were studied using a slow positron beam. Vacancy clusters are produced in all the implanted samples. It is found that the thermal recovery of these vacancies induced by different ions shows much difference. In case of B + and Al + -implantation, the vacancy clusters agglomerate to much larger size and might evolve to microvoids during annealing. However, for O + and P + ions, which are heavier than B + and Al + , the vacancies show a much weaker agglomeration process. The mechanism of such difference is discussed. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. On the possibility of a quantum bremsstrahlung induced self-modulation of a relativistic beam channeling in crystals

    International Nuclear Information System (INIS)

    Vysotskij, V.I.; Vorontsov, V.I.; Kuz'min, R.N.

    1987-01-01

    Physical predictions and quantitative estimations of a new physical effect - the phenomenon of quantum bremsstrahlung induced selfmodulation of a fast beam channeling in the crystals are considered and carried out. The occurrence of induced self-modulation results from nonstationary interference of proper waves of a channeled particle in the range of mutual coherence and with account of difference of selective bremsstrahlung losses of these waves. The modulation frequency for superrelativistic particles is shown to lie within the range from soft X-ray to hard gamma range. It proceeds from the estimations that modulation at these frequencies is preserved within the limits of macroscopically large ranges after the crystal attaining several meters. The maximum frequency of modulation for nonrelativistic heavy particles (protons) corresponds to the optical range

  3. Electron-beam-induced post-grafting polymerization of acrylic acid onto the surface of Kevlar fibers

    Science.gov (United States)

    Xu, Lu; Hu, Jiangtao; Ma, Hongjuan; Wu, Guozhong

    2018-04-01

    The surface of Kevlar fibers was successfully modified by electron beam (EB)-induced post-grafting of acrylic acid (AA). The generation of radicals in the fibers was confirmed by electron spin resonance (ESR) measurements, and the concentration of radicals was shown to increase as the absorbed dose increased, but decrease with increasing temperature. The influence of the synthesis conditions on the degree of grafting was also investigated. The surface microstructure and chemical composition of the modified Kevlar fibers were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The SEM images revealed that the surface of the grafted fibers was rougher than those of the pristine and irradiated fibers. XPS analysis confirmed an increase in C(O)OH groups on the surface of the Kevlar fibers, suggesting successful grafting of AA. These results indicate that EB-induced post-grafting polymerization is effective for modifying the surface properties of Kevlar fibers.

  4. Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy.

    Science.gov (United States)

    Eftekhari, Mohammad; Anbiaei, Robabeh; Zamani, Hanie; Fallahi, Babak; Beiki, Davood; Ameri, Ahmad; Emami-Ardekani, Alireza; Fard-Esfahani, Armaghan; Gholamrezanezhad, Ali; Seid Ratki, Kazem Razavi; Roknabadi, Alireza Momen

    2015-01-01

    Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right-sided cancer. To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring) were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT) to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions) over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol) was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed) and 36 patients with right-sided cancer (controls)] were enrolled. Dose-volume histogram (DVH) [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46). In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03) and anterolateral (17.1% versus 2.8%, P=0.049) walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS) of>3 was observed in twelve cases (34.3%), while in five of the controls (13.9%),(Odds ratio=1.3). There was no significant difference between the groups regarding left ventricular ejection fraction. The risk of radiation induced myocardial perfusion abnormality in patients treated with CRT on the

  5. Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

    Directory of Open Access Journals (Sweden)

    Mohammad Eftekhari

    2015-01-01

    Full Text Available Objective(s: Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right–sided cancer. Methods: To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. Results: A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed and 36 patients with right-sided cancer (controls] were enrolled. Dose-volume histogram (DVH [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46. In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03 and anterolateral (17.1% versus 2.8%, P=0.049 walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS of>3 was observed in twelve cases (34.3%, while in five of the controls (13.9%,(Odds ratio=1.3. There was no significant difference between the groups regarding left ventricular ejection fraction. Conclusion: The risk of radiation induced myocardial

  6. In situ observation of electron beam-induced phase transformation of CaCO3 to CaO via ELNES at low electron beam energies.

    Science.gov (United States)

    Golla-Schindler, Ute; Benner, Gerd; Orchowski, Alexander; Kaiser, Ute

    2014-06-01

    It is demonstrated that energy-filtered transmission electron microscope enables following of in situ changes of the Ca-L2,3 edge which can originate from variations in both local symmetry and bond lengths. Low accelerating voltages of 20 and 40 kV slow down radiation damage effects and enable study of the start and finish of phase transformations. We observed electron beam-induced phase transformation of single crystalline calcite (CaCO3) to polycrystalline calcium oxide (CaO) which occurs in different stages. The coordination of Ca in calcite is close to an octahedral one streched along the direction. Changes during phase transformation to an octahedral coordination of Ca in CaO go along with a bond length increase by 5 pm, where oxygen is preserved as a binding partner. Electron loss near-edge structure of the Ca-L2,3 edge show four separated peaks, which all shift toward lower energies during phase transformation at the same time the energy level splitting increases. We suggest that these changes can be mainly addressed to the change of the bond length on the order of picometers. An important pre-condition for such studies is stability of the energy drift in the range of meV over at least 1 h, which is achieved with the sub-Ångström low-voltage transmission electron microscope I prototype microscope.

  7. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, H.; Raynaud, C.; Bevilacqua, P.; Tournier, D.; Planson, D. [Ampère Laboratory - UMR 5005, 21, Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Vergne, B. [Franco-Allemand Institute of Saint-Louis ISL, 5, Rue du Général Cassagnou, 68300 Saint-Louis (France)

    2014-02-24

    Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption.

  8. Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

    International Nuclear Information System (INIS)

    Hamad, H.; Raynaud, C.; Bevilacqua, P.; Tournier, D.; Planson, D.; Vergne, B.

    2014-01-01

    Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption

  9. Active control of annular flow-induced vibration of axisymmetric elastic beam by the local gap width control

    International Nuclear Information System (INIS)

    Takada, Shoji; Shintani, Atsuhiko; Ito, Tomohiro; Fujita, Katsuhisa

    2011-01-01

    Flow-induced vibration may occur in the structures such as elastic beams subjected to annular flow in the narrow passage. Once the flow-induced vibration occurs, vibration amplitude becomes larger, consequently it causes a lot of troubles such as fatigue or failure in mechanical structures. In this paper, for the purpose to avoid these troubles, the active control of vibration of an axisymmetric elastic beam subjected to annular flow is investigated. An air-pressured actuator is attached on the surface of the circular cylinder for the vibrational control. As the shape of the actuator changes by control, the gap width in narrow passage changes, which causes the change of the fluid pressure. Therefore, the vibration of the fluid-structure coupled system can be suppressed. The fluid-structure coupled equation based on the Euler-Bernoulli type of partial differential equation and the Navier-Stokes equations is analytically derived including control terms. By applying the optimal control law to the coupled system, the unstable behavior is stabilized. The stability of the coupled system is investigated by eigenvalue analyses of controlled coupled equations. Numerical simulations are performed to investigate the efficiency of the proposed control method. (author)

  10. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  11. Analysis of the degradation induced by focused ion Ga3+ beam for the realization of piezoelectric nanostructures

    International Nuclear Information System (INIS)

    Remiens, D.; Liang, R. H.; Soyer, C.; Deresmes, D.; Troadec, D.; Quignon, S.; Da Costa, A.; Desfeux, R.

    2010-01-01

    Piezoelectric nanostructures (islands of dimensions in the lateral size range 50-500 nm) have been fabricated by focused Ga 3+ ion beam (FIB) etching on PbZr 0.54 Ti 0.46 O 3 thin films obtained by magnetron sputtering. The degradation induced by the etching process is investigated through the evolution of electromechanical activity measured by means of local piezoelectric hysteresis loops produced by piezoresponse force microscopy. The analysis of surface potential is performed by kelvin force microscopy and the measurement of current-voltage curves is carried out by conducting atomic force microscopy. Two kinds of structures, namely one based on crystallized films and the other based on amorphous ones, were studied. In this latter case, the amorphous films are postannealed after etching to obtain crystallized structure. For the structures based on the crystallized and then etched films, no piezoelectric signal was registered that evidences a serious degradation of material induced by Ga 3+ ion implantation. For the structures based on the films etched in amorphous state and then crystallized, the piezoresponse signal was near to that of the reference films (crystallized and not etched) whatever were the ion dose and the island dimensions. Even for very small lateral size (50 nm), no size effect was observed. The island shapes fabricated by Ga 3+ FIB etching process (islands with less than 50 nm lateral size) show a limitation of FIB processing and electron beam lithography seems to be necessary.

  12. The Cancer of the Prostate Risk Assessment (CAPRA) in patients treated with external beam radiation therapy: Evaluation and optimization in patients at higher risk of relapse

    International Nuclear Information System (INIS)

    Halverson, Schuyler; Schipper, Matthew; Blas, Kevin; Lee, Vivien; Sabolch, Aaron; Olson, Karin; Sandler, Howard M.; Feng, Felix Y.; Hamstra, Daniel A.

    2011-01-01

    Background: The Cancer of the Prostate Risk Assessment (CAPRA) was developed to predict freedom from biochemical failure (FFBF) following radical prostatectomy (RP). Its utility following external beam radiation therapy (EBRT) has not been externally evaluated. Methods: A retrospective study of 612 patients treated with dose-escalated EBRT at University of Michigan Medical Center. Results: Compared to the derivation cohort, EBRT treated patients had higher-risk disease (28% with CAPRA of 6–10 vs. 5%, respectively). A total of 114 patients (19%) had BF with 5-year BF ranging from 7% with CAPRA 0–3 to 35% with CAPRA 7–10. For RT patients the risk of BF at 5-year was similar to 4 surgical cohorts for CAPRA scores 0–2 but lower for all CAPRA scores ⩾ 3. The difference favoring RT increased with increasing CAPRA score reaching a 27–50% absolute improved at 5-years for CAPRA scores of 6–10. On multivariate analysis each CAPRA point increased the risk of BF (p < 0.0001) while Gleason pattern 5 in the biopsy also increased BF (p = 0.01) and long-term androgen deprivation therapy (ADT) significantly reduced the risk of BF (p = 0.015). Conclusions: Compared to surgical series the risk of BF was lower with dose-escalated EBRT with the greatest difference at the highest CAPRA scores.

  13. Ion beam modification of sputtered metal nitride thin films: A study of the induced microstructural changes

    International Nuclear Information System (INIS)

    Milosavljevic, M.; Perusko, D.; Popovic, M.; Novakovic, M.

    2008-01-01

    Single CrN and TiN and multilayered AlN/TiN and Al/Ti thin film structures (t = 240-280 nm) deposited on Si were irradiated with 120-200 keV Ar + ions to the fluences ranging from 1 x 10 11 5 to 4 x 10 16 ions/cm 2 . The metallic Al/Ti multilayered structure was also irradiated with high fluence (1- 2 x 10 17 /cm 2 ) nitrogen ions at 200 keV, in order to study interface mixing and formation of nitrides. Single component CrN and TiN thin films were found to grow in the form of a very fine polycrystalline columnar structures. Individual crystal grains were of the order of a few tens of nm in diameter, stretching from the substrate to the surface. After ion irradiation, the layers retain their polycrystalline structure, although the columns become disconnected, the resulting structures consisting of larger grains and nano-particles of the same phase. The implanted samples displayed higher electrical resistivity, presumably due to a higher concentration of point defects and the presence of nano-particles. In Al/Ti and AlN/TiN multilayers irradiated with Ar ions, the as-deposited structures exhibit well-defined, isolated polycrystalline Al and Ti, or AlN and TiN layers, with sharp interfaces. In the metallic system ion irradiation induced interface mixing which progressed with increasing the ion fluence. Mixing was most pronounced at the interfaces that are located around the projected ion range. The multilayered structure was essentially preserved, but the implanted samples exhibit much larger crystal grains. Also, the formation of lamellar columns stretching over a number of individual layers was observed. The AlN/TiN multilayered structures exhibited no measurable interface mixing on Ar irradiation, attributable to the nature of interatomic bonding and to mutual immiscibility of AlN and TiN. High fluence nitrogen ion irradiation of Al/Ti multilayers results in both the introduction of nitrogen into the structures as well as a high level of their intermixing. A

  14. Surface Casimir densities and induced cosmological constant in higher dimensional braneworlds

    International Nuclear Information System (INIS)

    Saharian, Aram A.

    2006-01-01

    We investigate the vacuum expectation value of the surface energy-momentum tensor for a massive scalar field with general curvature coupling parameter obeying the Robin boundary conditions on two codimension one parallel branes in a (D+1)-dimensional background spacetime AdS D 1 +1 xΣ with a warped internal space Σ. These vacuum densities correspond to a gravitational source of the cosmological constant type for both subspaces of the branes. Using the generalized zeta function technique in combination with contour integral representations, the surface energies on the branes are presented in the form of the sum of single-brane and second-brane-induced parts. For the geometry of a single brane both regions, on the left and on the right of the brane, are considered. At the physical point the corresponding zeta functions contain pole and finite contributions. For an infinitely thin brane taking these regions together, in odd spatial dimensions the pole parts cancel and the total zeta function is finite. The renormalization procedure for the surface energies and the structure of the corresponding counterterms are discussed. The parts in the surface densities generated by the presence of the second brane are finite for all nonzero values of the interbrane separation and are investigated in various asymptotic regions of the parameters. In particular, it is shown that for large distances between the branes the induced surface densities give rise to an exponentially suppressed cosmological constant on the brane. The total energy of the vacuum including the bulk and boundary contributions is evaluated by the zeta function technique and the energy balance between separate parts is discussed

  15. Calculation of electron-beam induced displacement in thin films by using parameter-reduced formulas

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Chen, Di [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States); Wang, Qingyu; Li, Zhongyu [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States)

    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. Ultra-long magnetization needle induced by focusing azimuthally polarized beams with a spherical mirror.

    Science.gov (United States)

    Hang, Li; Luo, Kai; Fu, Jian; Chang, Yizhe; Wang, Ying; Chen, Peifeng

    2018-03-20

    Based on extended Richards-Wolf theory for axisymmetric surfaces and the inverse Faraday effect, we propose the generation of a purely longitudinal magnetization needle by focusing Gaussian annular azimuthally polarized beams with a spherical mirror. The needle obtained has a longitudinal length varying hundreds to thousands of wavelengths while keeping the lateral size under 0.4λ, and the corresponding aspect ratio can easily reach more than 2000. It may be the first time that a magnetization needle whose aspect ratio is over 500 has been achieved. The approximate analytical expressions of the magnetization needle are given, and the longitudinal length is tunable by changing the value of the angular thickness and the position of the annular beams.

  17. 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.

  18. Ion-beam-induced aggregation in polystyrene: The influence of the molecular parameters

    International Nuclear Information System (INIS)

    Puglisi, O.; Licciardello, A.; Calcagno, L.; Foti, G.

    1988-01-01

    The formation of an insoluble gel under ion-beam bombardment is governed by ion-beam parameters and target parameters. Here reported is a study of the influence of the target molecular parameters on the sol--gel transition of ion-bombarded polystyrene with particular emphasis for the number-average molecular weight M-bar/sub n/. It is shown that the main parameter is the number of macromolcules of the film so that by adopting a ''corrected'' fluence F/n (ions per macromolecule), the different curves of the various polymers collapse in only one universal curve. The importance of the ''corrected'' fluence is shown also at molecular level and the MWD of the various polymers is similar at equal F/n values. An experimental model is outlined which explains the sol--gel transition on the basis of transition from an isolated-track regime to an overlap regime where the formation of insoluble giant macromolecules occurs

  19. Neutron-induced damage evolution under Beam Raster Scanner conditions for IFMIF

    International Nuclear Information System (INIS)

    Mota, Fernando; Ortiz, Christophe J.; Ibarra, Angel; Vila, Rafael

    2011-01-01

    The formation and evolution of defects in materials irradiated with a homogeneous neutron source and with the Beam Raster Scanner (BRS) solution was investigated. The intensity neutron source fluctuations inherent to the BRS system were determined using the neutron transport McDeLicious code. Defects generated during irradiation were calculated using the binary collision approximation MARLOWE code, using the primary knock-on atom (PKA) energy spectrum resulting from neutron interactions with the material. In order to predict the evolution of defects during irradiation, a Rate Theory model based on ab initio parameters was developed. Our model accounts for the migration of mobile defects, the formation of clusters and their recombination. As an example, we investigated defect evolution in Fe irradiated at room temperature in both beam configurations. Simulation results clearly indicate that the defect evolution expected in the BRS configuration is nearly the same as the one expected in a homogeneous irradiation system.

  20. Electron-beam-induced acoustic-wave enhancement of gaseous combustion

    International Nuclear Information System (INIS)

    Bidwell, S.W.; Bosch, R.A.; Gilgenbach, R.M.

    1989-01-01

    The combustion rate of premixed gases in a closed vessel was increased by injecting a high-current electron beam into the gas mixture within about 20 ms of spark ignition. This effect was observed with the fuels ethylene, methane, ethane, propane, and n-butane. Experimental results provide strong evidence that e-beam excitation of the fundamental longitudinal-acoustic mode of the cylindrical chamber is the mechanism of combustion enhancement. An observable combustion enhancement required that the amplitude of the fluid velocity oscillation in this acoustic mode be greater than or approximately equal to the flame propagation speed and was associated with a wrinkled or cellular flame structure with dimensions on the order of 1/2 cm. These results are in good agreement with values for the threshold acoustic velocity amplitude and dimension of cellular structure predicted for a periodically accelerated flame

  1. Experimental procedures to mitigate electron beam induced artifacts during in situ fluid imaging of nanomaterials

    International Nuclear Information System (INIS)

    Woehl, Taylor J.; Jungjohann, Katherine L.; Evans, James E.; Arslan, Ilke; Ristenpart, William D.; Browning, Nigel D.

    2013-01-01

    Scanning transmission electron microscopy of various fluid and hydrated nanomaterial samples has revealed multiple imaging artifacts and electron beam–fluid interactions. These phenomena include growth of crystals on the fluid stage windows, repulsion of particles from the irradiated area, bubble formation, and the loss of atomic information during prolonged imaging of individual nanoparticles. Here we provide a comprehensive review of these fluid stage artifacts, and we present new experimental evidence that sheds light on their origins in terms of experimental apparatus issues and indirect electron beam sample interactions with the fluid layer. A key finding is that many artifacts are a result of indirect electron beam interactions, such as production of reactive radicals in the water by radiolysis, and the associated crystal growth. The results presented here will provide a methodology for minimizing fluid stage imaging artifacts and acquiring quantitative in situ observations of nanomaterial behavior in a liquid environment

  2. Experimental procedures to mitigate electron beam induced artifacts during in situ fluid imaging of nanomaterials

    Energy Technology Data Exchange (ETDEWEB)

    Woehl, Taylor J., E-mail: tjwoehl@ucdavis.edu [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616 (United States); Jungjohann, Katherine L. [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616 (United States); Evans, James E. [Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616 (United States); Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Arslan, Ilke [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616 (United States); Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Ristenpart, William D. [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616 (United States); Department of Food Science and Technology, University of California, Davis, Davis, CA 95616 (United States); Browning, Nigel D. [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, CA 95616 (United States); Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616 (United States); Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2013-04-15

    Scanning transmission electron microscopy of various fluid and hydrated nanomaterial samples has revealed multiple imaging artifacts and electron beam–fluid interactions. These phenomena include growth of crystals on the fluid stage windows, repulsion of particles from the irradiated area, bubble formation, and the loss of atomic information during prolonged imaging of individual nanoparticles. Here we provide a comprehensive review of these fluid stage artifacts, and we present new experimental evidence that sheds light on their origins in terms of experimental apparatus issues and indirect electron beam sample interactions with the fluid layer. A key finding is that many artifacts are a result of indirect electron beam interactions, such as production of reactive radicals in the water by radiolysis, and the associated crystal growth. The results presented here will provide a methodology for minimizing fluid stage imaging artifacts and acquiring quantitative in situ observations of nanomaterial behavior in a liquid environment.

  3. Intense heavy ion beam-induced temperature effects in carbon-based stripper foils

    International Nuclear Information System (INIS)

    Kupka, K.; Tomut, M.; Simon, P.; Hubert, C.; Romanenko, A.; Lommel, B.; Trautmann, C.

    2015-01-01

    At the future FAIR facility, reliably working solid carbon stripper foils are desired for providing intermediate charge states to SIS18. With the expected high beam intensities, the foils experience enhanced degradation and limited lifetime due to severe radiation damage, stress waves, and thermal effects. This work presents systematic measurements of the temperature of different carbon-based stripper foils (amorphous, diamond-like, and carbon-nanotube based) exposed to 4.8 MeV/u U, Bi, and Au beams of different pulse intensities. Thermal and spectroscopic analyses were performed by means of infrared thermography and Fourier transform infrared spectroscopy. The resulting temperature depends on the foil thickness and strongly increases with increasing pulse intensity and repetition rate. (author)

  4. Optical forces induced behavior of a particle in a non-diffracting vortex beam

    Czech Academy of Sciences Publication Activity Database

    Šiler, Martin; Jákl, Petr; Brzobohatý, Oto; Zemánek, Pavel

    2012-01-01

    Roč. 20, č. 22 (2012), s. 24304-24319 ISSN 1094-4087 R&D Projects: GA ČR GPP205/11/P294; GA MŠk ED0017/01/01; GA MŠk LH12018 Institutional support: RVO:68081731 Keywords : optical vortex beam * tweezers * optical forces Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.546, year: 2012

  5. Estimation of neutral-beam-induced field reversal in MFTF by an approximate scaling law

    International Nuclear Information System (INIS)

    Shearer, J.W.

    1980-01-01

    Scaling rules are derived for field-reversed plasmas whose dimensions are common multiples of the ion gyroradius in the vacuum field. These rules are then applied to the tandem MFTF configuration, and it is shown that field reversal appears to be possible for neutral beam currents of the order of 150 amperes, provided that the electron temperature is at least 500 eV

  6. Functional brain imaging to investigate the higher brain dysfunction induced by diffuse brain injury

    International Nuclear Information System (INIS)

    Nariai, Tadashi; Inaji, Motoki; Ohno, Kikuo; Hiura, Mikio; Ishii, Kenji; Hosoda, Chihiro

    2011-01-01

    Higher brain dysfunction is the major problem of patients who recover from neurotrauma the prevents them from returning to their previous social life. Many such patients do not have focal brain damage detected with morphological imaging. We focused on studying the focal brain dysfunction that can be detected only with functional imaging with positron emission tomography (PET) in relation to the score of various cognition batteries. Patients who complain of higher brain dysfunction without apparent morphological cortical damage were recruited for this study. Thirteen patients with diffuse axonal injury (DAI) or cerebral concussion was included. They underwent a PET study to image glucose metabolism by 18 F-fluorodeoxyglucose (FDG), and central benodiazepine receptor (cBZD-R) (marker of neuronal body) by 11 C-flumazenil, together with cognition measurement by WAIS-R, WMS-R, and WCST etc. PET data were compared with age matched normal controls using statistical parametric mapping (SPM)2. DAI patients had a significant decrease in glucose matabolism and cBZD-R distribution in the cingulated cortex than normal controls. Patients diagnosed with concussion because of shorter consciousness disturbance also had abnormal FDG uptake and cBZD-R distribution. Cognition test scores were variable among patients. Degree of decreased glucose metabolism and cBZD-R distribution in the dominant hemishphere corresponded well to the severity of cognitive disturbance. PET molecular imaging was useful to depict focal cortical dysfunction of neurotrauma patients even when morphological change was not apparent. This method may be promising to clarify the pathophysiology of higher brain dysfunction of patients with diffuse axonal injury or chronic traumatic encephalopathy. (author)

  7. Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams

    International Nuclear Information System (INIS)

    Khan, Inamullah; François, Raoul; Castel, Arnaud

    2014-01-01

    This paper studies the evolution of reinforcement corrosion in comparison to corrosion crack width in a highly corroded reinforced concrete beam. Cracking and corrosion maps of the beam were drawn and steel reinforcement was recovered from the beam to observe the corrosion pattern and to measure the loss of mass of steel reinforcement. Maximum steel cross-section loss of the main reinforcement and average steel cross-section loss between stirrups were plotted against the crack width. The experimental results were compared with existing models proposed by Rodriguez et al., Vidal et al. and Zhang et al. Time prediction models for a given opening threshold are also compared to experimental results. Steel cross-section loss for stirrups was also measured and was plotted against the crack width. It was observed that steel cross-section loss in the stirrups had no relationship with the crack width of longitudinal corrosion cracks. -- Highlights: •Relationship between crack and corrosion of reinforcement was investigated. •Corrosion results of natural process and then corresponds to in-situ conditions. •Comparison with time predicting model is provided. •Prediction of load-bearing capacity from crack pattern was studied

  8. Electron beam induced purification of dilute off gases from industrial processes and automobile tunnels

    International Nuclear Information System (INIS)

    Paur, H.-R.; Maetzing, H.

    1993-01-01

    The electron beam process has proved to be an efficient method for the removal of inorganic pollutants from flue gas. Since it simulates natural processes which occur in the atmospheric photochemistry, it appeared attractive to investigate the potential of the e-beam process to clean off-gases which contain hydrocarbon and inorganic trace components. Such emissions arise from industrial processes and from automobile tunnels. Commercial solvents were vaporized in air and irradiated with energetic electrons (300 keV). CO, CO 2 and aerosol particles were found as products and were determined quantitatively. The aerosol particles can be collected by a gravel bed filter and can be removed by combustion or biological degradation. From experiments and model calculations it was found that the e-beam process is a very economic tool to remove hydrocarbons from large off-gas volumes at initial concentrations of 50-100 mg C/m 3 , and that NO x can be removed very efficiently from tunnel off-gas. (author)

  9. A beamline design and data acquisition with the 20-MeV, 20-ps electron beam for the higher-order mode studies of the APS SR-rf cavities

    International Nuclear Information System (INIS)

    Song, J.; Nassiri, A.; Daly, R.

    1993-01-01

    A beamline has been designed and assembled to use the ANL Chemistry Division 20-MeV electron linac for the testing of higher-order mode excitation and damping in rf cavities. The beamline consists of two sections (a beam collimating section with a 1.5 inches-OD vacuum line, and a cavity test section with a 3 inches-OD vacuum line), separated by two double aluminum foil windows. The beam diagnostics consist of a stripline beam position monitor, integrating current transformers, fluorescent screens, and a Faraday cup. EPICS (Experimental Physics and Industrial Control System) is used for beamline control, monitoring, and data acquisition. Also described is the diagnostic system used for beam image capture and analysis using EPICS-controlled hardware and PV-WAVE software. The rf cavity measurement will be described in a separate paper

  10. Inhibition of DNA repair by whole body irradiation induced nitric oxide leads to higher radiation sensitivity in lymphocytes

    International Nuclear Information System (INIS)

    Sharma, Deepak; Santosh Kumar, S.; Raghu, Rashmi; Maurya, D.K.; Sainis, K.B.

    2007-01-01

    Full text: It is well accepted that the sensitivity of mammalian cells is better following whole body irradiation (WBI) as compared to that following in vitro irradiation. However, the underlying mechanisms are not well understood. Following WBI, the lipid peroxidation and cell death were significantly higher in lymphocytes as compared to that in vitro irradiated lymphocytes. Further, WBI treatment of tumor bearing mice resulted in a significantly higher inhibition of EL-4 cell proliferation as compared to in vitro irradiation of EL-4 cells. The DNA repair was significantly slower in lymphocytes obtained from WBI treated mice as compared to that in the cells exposed to same dose of radiation in vitro. Generation of nitric oxide following irradiation and also its role in inhibition of DNA repair have been reported, hence, its levels were estimated under both WBI and in vitro irradiation conditions. Nitric oxide levels were significantly elevated in the plasma of WBI treated mice but not in the supernatant of in vitro irradiated cells. Addition of sodium nitroprusside (SNP), a nitric oxide donor to in vitro irradiated cells inhibited the repair of DNA damage and sensitized cells to undergo cell death. It also enhanced the radiation-induced functional impairment of lymphocytes as evinced from suppression of mitogen-induced IL-2, IFN-γ and bcl-2 mRNA expression. Administration of N G -nitro-L-arginine-methyl-ester(L-NAME), a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. Our results indicated that nitric oxide plays a role in the higher radiosensitivity of lymphocytes in vivo by inhibiting repair of DNA damage

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

    Indian Academy of Sciences (India)

    phase of the probe pulse are functions of the pump pulse characteristics. Moreover, it has been predicted that a probe pulse that is co-propagating in an enhanced induced phase modulation nonlinear two-dimensional medium in the presence of a pump may be transformed into induced superspikes in space and time [22].

  12. 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 co...

  13. Evaluation of the Induced Activity in Air by the External Proton Beam in the Target Room of the Proton Accelerator Facility of Proton Engineering Frontier Project

    International Nuclear Information System (INIS)

    Lee, Cheol Woo; Lee, Young Ouk; Cho, Young Sik; Ahn, So Hyun

    2007-01-01

    One of the radiological concerns is the worker's exposure level and the concentration of the radionuclides in the air after shutdown, for the safety analysis on the proton accelerator facility. Although, the primary radiation source is the protons accelerated up to design value, all of the radio-nuclide is produced from the secondary neutron and photon induced reaction in air. Because, the protons don't penetrate the acceleration equipment like the DTL tank wall or BTL wall, secondary neutrons or photons are only in the air in the accelerator tunnel building because of the short range of the proton in the materials. But, for the case of the target rooms, external proton beams are occasionally used in the various experiments. When these external proton beams travel through air from the end of the beam transport line to the target, they interact directly with air and produce activation products from the proton induced reaction. The external proton beam will be used in the target rooms in the accelerator facility of the Proton Accelerator Frontier Project (PEFP). In this study, interaction characteristics of the external proton beam with air and induced activity in air from the direct interaction of the proton beam were evaluated

  14. 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. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  15. Combined experimental and numerical investigation of energy harness utilizing vortex induced vibration over half cylinder using piezoelectric beams

    Science.gov (United States)

    Ahmed, Md. Tusher; Hossain, Md. Tanver; Rahman, Md. Ashiqur

    2017-06-01

    Energy harvesting technology has the ability to create self-powered electronic systems that do not rely on battery power for their operation. Wind energy can be converted into electricity via a piezoelectric transducer during the air flow over a cylinder. The vortex-induced vibration over the cylinder causes the piezoelectric beam to vibrate. Thus useful electric energy at the range 0.2-0.3V is found which can be useful for self-powering small electronic devices. In the present study, prototypes of micro-energy harvester with a shape of 65 mm × 37 mm × 0.4 mm are developed and tested for airflow over D-shaped bluff body for diameters of 15, 20 and 28mm in an experimental setup consisting of a long wind tunnel of 57cm × 57cm with variable speeds of the motor for different flow velocities and the experimental setup is connected at the downstream where flow velocity is the maximum. Experimental results show that the velocity and induced voltage follows a regular linear pattern. A maximum electrical potential of 140 mV for velocity of 1.1 ms-1 at a bluff body diameter of 15 mm is observed in the energy harvester that can be applied in many practical cases for self-powering electronic devices. The simulation of this energy harvesting phenomena is then simulated using COMSOLE multi-physics. Diameter of the bluff bodies as well as flow velocity and size of cantilever beam are varied and the experimental findings are found to be in good agreement with the simulated ones. The simulations along with the experimental data show the possibility of generating electricity from vortex induced vibration and can be applied in many practical cases for self-powering electronic devices.

  16. Electron pulsed beam induced processing of thin film surface by Nb3Ge deposited into a stainless steel tape

    International Nuclear Information System (INIS)

    Vavra, I.; Korenev, S.A.

    1988-01-01

    A surface of superconductive thin film of Nb 3 Ge deposited onto a stainless steel tape was processed using the electron beam technique. The electron beam used had the following parameters: beam current density from 400 to 1000 A/cm 2 ; beam energy 100 keV; beam impulse length 300 ns. By theoretical analysis it is shown that the heating of film surface is an adiabatic process. It corresponds to our experimental data and pictures showing a surface remelting due to electron beam influence. After beam processing the superconductive parameters of the film remain unchanged. Roentgenograms have been analysed of Nb 3 Ge film surface recrystallized due to electron beam influence

  17. Sevoflurane Induces DNA Damage Whereas Isoflurane Leads to Higher Antioxidative Status in Anesthetized Rats

    Directory of Open Access Journals (Sweden)

    Thalita L. A. Rocha

    2015-01-01

    Full Text Available Taking into account that there are controversial antioxidative effects of inhalational anesthetics isoflurane and sevoflurane and absence of comparison of genotoxicity of both anesthetics in animal model, the aim of this study was to compare DNA damage and antioxidant status in Wistar rats exposed to a single time to isoflurane or sevoflurane. The alkaline single-cell gel electrophoresis assay (comet assay was performed in order to evaluate DNA damage in whole blood cells of control animals (unexposed; n = 6 and those exposed to 2% isoflurane (n = 6 or 4% sevoflurane (n = 6 for 120 min. Plasma antioxidant status was determined by 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay. There was no statistically significant difference between isoflurane and sevoflurane groups regarding hemodynamic and temperature variables (P > 0.05. Sevoflurane significantly increased DNA damage compared to unexposed animals (P = 0.02. In addition, Wistar rats anesthetized with isoflurane showed higher antioxidative status (MTT than control group (P = 0.019. There were no significant differences in DNA damage or antioxidant status between isoflurane and sevoflurane groups (P > 0.05. In conclusion, our findings suggest that, in contrast to sevoflurane exposure, isoflurane increases systemic antioxidative status, protecting cells from DNA damage in rats.

  18. Post-ion beam induced degradation of copper layers in transmission electron microscopy specimens

    Science.gov (United States)

    Seidel, F.; Richard, O.; Bender, H.; Vandervorst, W.

    2015-11-01

    Copper containing transmission electron microscopy (TEM) specimens frequently show corrosion after focused ion beam (FIB) preparation. This paper reveals that the corrosion product is a Cu-S phase growing over the specimen surface. The layer is identified by energy-dispersive x-ray spectroscopy, and lattice spacing indexing of power spectra patterns. The corrosion process is further studied by TEM on cone-shaped specimens, which are intentionally stored after FIB preparation with S flakes for short time. Furthermore, a protective method against corrosion is developed by varying the time in the FIB vacuum and the duration of a subsequent plasma cleaning.

  19. Ion-implantation induced defects in ZnO studied by a slow positron beam

    International Nuclear Information System (INIS)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A.; Sekiguchi, T.; Suzuki, R.

    2004-01-01

    Introduction and annealing behavior of defects in Al + -implanted ZnO have been studied using an energy variable slow positron beam. Vacancy clusters are produced after Al + -implantation. With increasing ion dose above 10 14 Al + /cm 2 the implanted layer is amorphized. Heat treatment up to 600 C enhances the creation of large voids that allow the positronium formation. The large voids disappear accompanying the recrystallization process by further heat treatment above 600 C. Afterwards, implanted Al impurities are completely activated to contribute to the n-type conduction. The ZnO crystal quality is also improved after recrystallization. (orig.)

  20. Propagation of photons induced by a proton beam in a quartz bar

    International Nuclear Information System (INIS)

    Plaszczynski, S.; Torassa, E.; Wormser, G.; Aleksan, R.; Amadon, A.; Besson, P.; Bourgeois, P.; Monchenault, G.H.; Jarry, P.; Lemaire, M.C.; Lemeur, J.; London, G.; Robert, J.P.

    1996-01-01

    For the BABAR experiment, an amplitude and timing analysis of photons produced by a proton beam in a quartz bar has been performed. The photoelectron yield is obtained for different angles and positions. It is found that the linear speed of propagation of the Cherenkov photons through the bar is well described y internal reflections. The timing analysis reveals also the existence of an unexpected parasite light component, not described by the simulation. However, all the results can be reproduced by adding an isotropic scintillation of about 4 photons/cm in the quartz bar on the trajectory of the primary proton, in 50 % of the cases. (author)

  1. 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...... 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...

  2. Ion-implantation induced defects in ZnO studied by a slow positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Z.Q.; Maekawa, M.; Kawasuso, A. [Japan Atomic Energy Research Institute, Gunma (Japan); Sekiguchi, T. [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan); Suzuki, R. [National Inst. of Advanced Industrial Science and Technology, Tsukuba, Ibaraki (Japan)

    2004-07-01

    Introduction and annealing behavior of defects in Al{sup +}-implanted ZnO have been studied using an energy variable slow positron beam. Vacancy clusters are produced after Al{sup +}-implantation. With increasing ion dose above 10{sup 14} Al{sup +}/cm{sup 2} the implanted layer is amorphized. Heat treatment up to 600 C enhances the creation of large voids that allow the positronium formation. The large voids disappear accompanying the recrystallization process by further heat treatment above 600 C. Afterwards, implanted Al impurities are completely activated to contribute to the n-type conduction. The ZnO crystal quality is also improved after recrystallization. (orig.)

  3. Propagation of photons induced by a proton beam in a quartz bar

    International Nuclear Information System (INIS)

    Plaszczynski, S.; Torassa, E.; Wormser, G.; Aleksan, R.; Amadon, A.; Besson, P.; Bourgeois, P.; Monchenault, G.H.

    1995-01-01

    For the BABAR experiment, an amplitude and timing analysis produced by a proton beam in a quartz bar has been performed. The photoelectron yield is obtained for different angles and positions. It is found that the linear speed of propagation of the Cherenkov photons through the bar is well described by internal reflections. The timing analysis reveals also the existence of an unexpected parasite light component, not described by the simulation. However, all the results can be reproduced by adding an isotopic scintillation of about 4 photons/cm in the quartz bar on the trajectory of the primary proton, in 50 % of the cases. (authors)

  4. Molecular dynamics studies of the ion beam induced crystallization in silicon

    International Nuclear Information System (INIS)

    Marques, L.A.; Caturla, M.J.; Huang, H.

    1995-01-01

    We have studied the ion bombardment induced amorphous-to-crystal transition in silicon using molecular dynamics techniques. The growth of small crystal seeds embedded in the amorphous phase has been monitored for several temperatures in order to get information on the effect of the thermal temperature increase introduced by the incoming ion. The role of ion-induced defects on the growth has been also studied

  5. Electron beam induced strong organic/inorganic grafting for thermally stable lithium-ion battery separators

    Science.gov (United States)

    Choi, Yunah; Kim, Jin Il; Moon, Jungjin; Jeong, Jongyeob; Park, Jong Hyeok

    2018-06-01

    A tailored interface between organic and inorganic materials is of great importance to maximize the synergistic effects from hybridization. Polyethylene separators over-coated with inorganic thin films are the state-of-the art technology for preparing various secondary batteries with high safety. Unfortunately, the organic/inorganic hybrid separators have the drawback of a non-ideal interface, thus causing poor thermal/dimensional stability. Here, we report a straightforward method to resolve the drawback of the non-ideal interface between vapor deposited SiO2 and polyethylene separators, to produce a highly stable lithium-ion battery separator through strong chemical linking generated by direct electron beam irradiation. The simple treatment with an electron beam with an optimized dose generates thermally stable polymer separators, which may enhance battery safety under high-temperature conditions. Additionally, the newly formed Si-O-C or Si-CH3 chemical bonding enhances electrolyte-separator compatibility and thus may provide a better environment for ionic transport between the cathode and anode, thereby leading to better charge/discharge behaviors.

  6. Ion-beam bombardment induced texture in nickel substrates for coated high-Tc superconductors

    International Nuclear Information System (INIS)

    Wang, S S; Wu, K; Zhou, Y; Godfrey, A; Meng, J; Liu, M L; Liu, Q; Liu, W; Han, Z

    2003-01-01

    Biaxially textured metal substrates are often used for making YBa 2 Cu 3 O 7-x coated conductors with high critical current density. Generally, specific rolling and high-temperature annealing procedures are required to obtain the biaxial texture for metal substrates. Here, we report on a new method for developing strongly biaxially textured grain structure in rolled nickel tape by argon ion-beam bombardment. X-ray diffraction (XRD) θ-2θ scans have shown that a (200) diffraction peak intensity of the Ni foil processed by ion-beam structure modification (ISM) is two orders of magnitude greater than that of cold-rolled foil, while the (111) and (220) intensities are very weak. In the ISM processed Ni foils, from the rocking curve, the full width at half maximum (FWHM) value of the (200) peak has been found to be less than 5.9 deg., whilst the in-plane FWHM obtained from a pole figure analysis is just 8 deg. We discuss the possible mechanisms leading to the texture changes during ISM. (rapid communication)

  7. Vertical Growth of Superconducting Crystalline Hollow Nanowires by He+ Focused Ion Beam Induced Deposition.

    Science.gov (United States)

    Córdoba, Rosa; Ibarra, Alfonso; Mailly, Dominique; De Teresa, José Ma

    2018-02-14

    Novel physical properties appear when the size of a superconductor is reduced to the nanoscale, in the range of its superconducting coherence length (ξ 0 ). Such nanosuperconductors are being investigated for potential applications in nanoelectronics and quantum computing. The design of three-dimensional nanosuperconductors allows one to conceive novel schemes for such applications. Here, we report for the first time the use of a He + focused-ion-beam-microscope in combination with the W(CO) 6 precursor to grow three-dimensional superconducting hollow nanowires as small as 32 nm in diameter and with an aspect ratio (length/diameter) of as much as 200. Such extreme resolution is achieved by using a small He + beam spot of 1 nm for the growth of the nanowires. As shown by transmission electron microscopy, they display grains of large size fitting with face-centered cubic WC 1-x phase. The nanowires, which are grown vertically to the substrate, are felled on the substrate by means of a nanomanipulator for their electrical characterization. They become superconducting at 6.4 K and show large critical magnetic field and critical current density resulting from their quasi-one-dimensional superconducting character. These results pave the way for future nanoelectronic devices based on three-dimensional nanosuperconductors.

  8. Spatial control of cell attachment, proliferation, and differentiation using ion-beam induced thin films

    International Nuclear Information System (INIS)

    Tanaka, Toshiyuki; Suzuki, Yoshiaki

    2014-01-01

    Highlights: • Cellular films can be obtained ion-beam irradiation and cell culture. • Film shapes were controlled by patterned irradiation. • Cellular films were firmly attached each other. • Tubular constructions were fabricated by wide-patterned irradiation. • Nerve growth direction was controlled by varying the pattern widths. - Abstract: In this study, cellular films were fabricated by ion-beam irradiation into poly-L-lactic acid sheets and cell culture. The cellular film shapes can be controlled by pattern masks. We performed spatial cell patterning using three types of cells: fibroblasts, endothelial cells, and nerve-like cells. First, multi-layered cellular construct was fabricated by stacking fibroblast cellular films. When three cellular films were stacked and incubated, these films firmly attached to each other. Second, tubular constructs were fabricated by endothelial cell culture on linearly patterned surfaces with wide widths of 80, 120, 160, and 200 μm. The patterned cellular films were rounded into vessel-like structure. The diameters of the constructs depend upon the pattern widths. Finally, we controlled cell attachment and nerve growth of nerve-like cells by using linearly patterned surfaces with narrow widths of 10, 30, and 50 μm. Nerve growth direction was controlled by varying the pattern widths. In the case of 10 μm, the attached cells and nerve growth were straight on the patterned thin films. These cell patterning techniques are expected to have applications in tissue engineering, cell transplantation, and in vitro tissue modeling

  9. Recent advances using electron beam analysis to detect cuticular changes induced by air pollution

    International Nuclear Information System (INIS)

    Krause, C.R.

    1994-01-01

    Invisible or ''hidden injury'', terms from the earliest air quality literature, expressed the diagnostician's frustration in identifying abiotic disease symptoms. Direct visualization was not technically possible until the advent of electron beam analysis (EBA) hardware and software. Electron beam analysis, a combination of scanning electron microscopy (SEM) energy dispersive X-ray analysis (EDXA), and computer-controlled image processing (CCIP) is useful for detecting changes in the cuticle and adjacent cells due to common phytotoxicants. Artifacts, caused by improper specimen preparation, inherent in the high vacuum of SEM and use of hydrated plant samples, fill the literature. Unique methodologies are necessary to interpret the minute changes to plant surfaces caused by a variety of environmental stresses such as sulfur dioxide, ozone, acidic deposition, pesticide residues, NACl, etc. EBA was used to show: the progression of surface alterations that occur to stomata of hybrid poplar (Populus spp.) following exposure to SO 2 and O 3 ; between SO 2 -sensitive and SO 2 -tolerant clones of eastern white pine (Pinus strobus L.). CCIP was especially useful in determining that acidified rain or mist and O 3 do not physically erode existing epicuticular wax of red spruce (Picea rubens Sarg.) as previous literature stated. EBA was used to correlate field and laboratory data showing similar injury to epistomatal wax of red spruce. Improved field emission microscopy and EDXA that offer increased resolution with little sample preparation can provide opportunities to observe cuticular modifications not previously available. (orig.)

  10. Modified electron beam induced current technique for in(Ga)As/InAsSb superlattice infrared detectors

    Science.gov (United States)

    Yoon, N.; Reyner, C. J.; Ariyawansa, G.; Duran, J. M.; Scheihing, J. E.; Mabon, J.; Wasserman, D.

    2017-08-01

    Electron beam induced current (EBIC) measurements provide a powerful tool for characterizing semiconductor based materials and devices. By measuring the current generated by the electron beam of a scanning electron microscope (SEM), EBIC allows us to extract the minority carrier diffusion length (L) and the surface recombination velocity to diffusivity ratio (S/D) of a material. When combined with information on minority carrier lifetime (τ), for instance from time-resolved photoluminescence measurements, the minority carrier mobility of the material can be extracted. However, the EBIC technique relies heavily on the accurate modeling of the carrier generation and collection process. Traditionally, this was achieved using a combination of empirical analytical expressions (and later Monte Carlo simulations) for carrier generation and analytical diffusion/recombination expressions for carrier collection. This approach introduces significant uncertainties into the extracted material parameters. Here, we present a numerical approach to EBIC modeling which improves the spatial resolution of our model, while also retaining information regarding the relative EBIC signal as a function of incident beam energies and currents. We apply this technique to investigate the temperature dependent minority carrier mobility of InAs/InAsSb and InGaAs/InAsSb strained layer superlattice infrared detectors and compare our results to the values obtained using external quantum efficiency measurements of the same samples. Our approach not only allows for an improvement in the uncertainty of the extracted material parameters, but also offers insight into the material and device behavior as a function of nonequilibrium carrier concentration. The technique presented here offers potentially improved characterization of not only infrared detectors, but a range of semiconductor-based devices.

  11. Irradiation With Carbon Ion Beams Induces Apoptosis, Autophagy, and Cellular Senescence in a Human Glioma-Derived Cell Line

    International Nuclear Information System (INIS)

    Jinno-Oue, Atsushi; Shimizu, Nobuaki; Hamada, Nobuyuki; Wada, Seiichi; Tanaka, Atsushi; Shinagawa, Masahiko; Ohtsuki, Takahiro; Mori, Takahisa; Saha, Manujendra N.; Hoque, Ariful S.; Islam, Salequl; Kogure, Kimitaka; Funayama, Tomoo; Kobayashi, Yasuhiko

    2010-01-01

    Purpose: We examined biological responses of human glioma cells to irradiation with carbon ion beams (C-ions). Methods and Materials: A human glioma-derived cell line, NP-2, was irradiated with C-ions. Apoptotic cell nuclei were stained with Hoechst 33342. Induction of autophagy was examined either by staining cells with monodansylcadaverine (MDC) or by Western blotting to detect conversion of microtuble-associated protein light chain 3 (MAP-LC3) (LC3-I) to the membrane-bound form (LC3-II). Cellular senescence markers including induction of senescence-associated β-galactosidase (SA-β-gal) were examined. The mean telomere length of irradiated cells was determined by Southern blot hybridization. Expression of tumor suppressor p53 and cyclin/cyclin-dependent kinase inhibitor p21 WAF1/CIP1 in the irradiated cells was analyzed by Western blotting. Results: When NP-2 cells were irradiated with C-ions at 6 Gy, the major population of the cells died of apoptosis and autophagy. The residual fraction of attached cells ( WAF1/CIP1 was induced in NP-2 cells after irradiation. Furthermore, we found that irradiation with C-ions induced cellular senescence in a human glioma cell line lacking functional p53. Conclusions: Irradiation with C-ions induced apoptosis, autophagy, and cellular senescence in human glioma cells.

  12. 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.

  13. Formation of plasmid DNA strand breaks induced by low-energy ion beam: indication of nuclear stopping effects

    International Nuclear Information System (INIS)

    Chen Yu; Jiang Bingyao; Chen Youshan; Ding Xingzhao; Liu Xianghuai; Chen Ceshi; Guo Xinyou; Yin Guanglin

    1998-01-01

    Plasmid pGEM 3zf(+) was irradiated by nitrogen ion beam with energies between 20 and 100 keV and the fluence kept as 1 x 10 12 ions/cm 2 . The irradiated plasmid was assayed by neutral electrophoresis and quantified by densitometry. The yields of DNA with single-strand and double-strand breaks first increased then decreased with increasing ion energy. There was a maximal yield value in the range of 20-100 keV. The relationship between DNA double-strand breaks (DSB) cross-section and linear energy transfer (LET) also showed a peak-shaped distribution. To understand the physical process during DNA strand breaks, a Monte Carlo calculation code known as TRIM (Transport of Ions in Matter) was used to simulate energy losses due to nuclear stopping and to electronic stopping. It can be assumed that nuclear stopping plays a more important role in DNA strand breaks than electronic stopping in this energy range. The physical mechanisms of DNA strand breaks induced by a low-energy ion beam are also discussed. (orig.)

  14. Impact of filling scheme on beam induced RF heating in CERN LHC and HL-LHC

    CERN Document Server

    AUTHOR|(CDS)2241936; De Vito, Luca; Salvant, Benoit

    At CERN, after the first maintenance cycle (Long Shutdown 1, LS1) of the Large Hadron Collider (LHC), several sectors of the accelerator present a beam-induced heating much larger than expectations. This work compares data measured by cryogenic instrumentation with the expected heat load for various filling schemes and shows that impedance is not reasonably the major cause of the additional heat load. With this aim, the scaling of the power loss is analyzed carefully. In particular the scaling of the computed power loss from beam coupling impedance with the number of bunches is well understood only for a very broad band Impedance and for a very narrow band Impedance in ideal filling schemes that assume that the machine is full of equispaced bunches. This thesis analyzes also this dependence with number of bunches of the impedance of a resonator for a wide range of quality factors and more realistic filling schemes. The commonly assumed scaling with the square of number of bunches for narrow band resonator...

  15. Photoluminescence of radiation-induced color centers in lithium fluoride thin films for advanced diagnostics of proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Piccinini, M., E-mail: massimo.piccinini@enea.it; Ampollini, A.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Vincenti, M. A.; Montereali, R. M. [ENEA, C.R. Frascati, UTAPRAD, Technical Unit for Development and Applications of Radiations, Via E. Fermi 45, 00044 Frascati (Rome) (Italy); Ambrosini, F. [University Sapienza-Roma I, Piazzale Aldo Moro 5, 00185 Rome (Italy); Nichelatti, E. [ENEA, C.R. Casaccia, UTTMAT, Technical Unit for Materials Technologies, Via Anguillarese 301, 00123 S. Maria di Galeria (Rome) (Italy)

    2015-06-29

    Systematic irradiation of thermally evaporated 0.8 μm thick polycrystalline lithium fluoride films on glass was performed by proton beams of 3 and 7 MeV energies, produced by a linear accelerator, in a fluence range from 10{sup 11} to 10{sup 15} protons/cm{sup 2}. The visible photoluminescence spectra of radiation-induced F{sub 2} and F{sub 3}{sup +} laser active color centers, which possess almost overlapping absorption bands at about 450 nm, were measured under laser pumping at 458 nm. On the basis of simulations of the linear energy transfer with proton penetration depth in LiF, it was possible to obtain the behavior of the measured integrated photoluminescence intensity of proton irradiated LiF films as a function of the deposited dose. The photoluminescence signal is linearly dependent on the deposited dose in the interval from 10{sup 3} to about 10{sup 6 }Gy, independently from the used proton energies. This behavior is very encouraging for the development of advanced solid state radiation detectors based on optically transparent LiF thin films for proton beam diagnostics and two-dimensional dose mapping.

  16. Photoluminescence of radiation-induced color centers in lithium fluoride thin films for advanced diagnostics of proton beams

    Science.gov (United States)

    Piccinini, M.; Ambrosini, F.; Ampollini, A.; Picardi, L.; Ronsivalle, C.; Bonfigli, F.; Libera, S.; Nichelatti, E.; Vincenti, M. A.; Montereali, R. M.

    2015-06-01

    Systematic irradiation of thermally evaporated 0.8 μm thick polycrystalline lithium fluoride films on glass was performed by proton beams of 3 and 7 MeV energies, produced by a linear accelerator, in a fluence range from 1011 to 1015 protons/cm2. The visible photoluminescence spectra of radiation-induced F2 and F3+ laser active color centers, which possess almost overlapping absorption bands at about 450 nm, were measured under laser pumping at 458 nm. On the basis of simulations of the linear energy transfer with proton penetration depth in LiF, it was possible to obtain the behavior of the measured integrated photoluminescence intensity of proton irradiated LiF films as a function of the deposited dose. The photoluminescence signal is linearly dependent on the deposited dose in the interval from 103 to about 106 Gy, independently from the used proton energies. This behavior is very encouraging for the development of advanced solid state radiation detectors based on optically transparent LiF thin films for proton beam diagnostics and two-dimensional dose mapping.

  17. Evaluation on effects of chloride-induced deterioration on mechanical properties of RC beams with cracking damage

    International Nuclear Information System (INIS)

    Matsuo, Toyofumi; Matsumura, Takuro; Otsuka, Taku

    2015-01-01

    This paper discusses the influence of chloride-induced deterioration on mechanical properties of aging reinforced concrete (RC) structures and the applicability of the material degradation model that takes reinforcing steel corrosion into consideration for finite element analysis. We conducted the corrosion tests under the simulated tidal environment and the flexural loading tests for the RC beams with cracking damage and initial defects. Then, the experimental results were numerically correlated to validate the devised modeling. The obtained results were summarized as follows: (a) The cracking damage in specimens caused a minor effect on the reinforcing steel corrosion in the case where the thickness of cover concrete was 40 mm and main rebars did not yield before chloride attack. On the other hand the maximum corrosion ratio of the deteriorated part became considerably larger than that of the non-cracking part in the specimens where the cover concrete were removed partially to simulate spalling by the severe corrosion. (b) Based on the test results, we derived the corrosion velocity of reinforcing steel corresponding to cracking damage degrees. (c) In FEM analyses, we showed that the above modeling can estimate the flexural strength of RC beams in consideration of the degradation in elongation performance of reinforcing steel due to corrosion. (author)

  18. Phase measurement and control of pulsed charged beams

    International Nuclear Information System (INIS)

    Lewis, R.N.

    1978-01-01

    A method and system is described that measures and controls the arrival phase of a pulsed ion beam. The repetitive beam pulse passes through and resonantly excites a high-Q structure, tuned to the beam repetition frequency or to a higher harmonic thereof. A reference signal of the same frequency is phase-flipped from -90 0 to +90 0 at a high audio rate and also coupled to the resonator. The low-level output signal, comprised of the vector sum of the beam-induced signal and the phase-flipped reference, is amplified and processed to obtain phase information. The system is usable for beams with average currents as low as a few picoamperes and can be used in the measurement and control of pulsed beam experiments involving timing, the control of beam phase for rf particle accelerators and the nondestructive measurement of beam energy. (Auth.)

  19. Investigation of Fano resonances induced by higher order plasmon modes on a circular nano-disk with an elongated cavity

    KAUST Repository

    Amin, Muhammad Ruhul

    2012-08-10

    In this paper, a planar metallic nanostructure design, which supports two distinct Fano resonances in its extinction cross-section spectrum under normally incident and linearly polarized electromagnetic field, is proposed. The proposed design involves a circular disk embedding an elongated cavity; shifting and rotating the cavity break the symmetry of the structure with respect to the incident field and induce higher order plasmon modes. As a result, Fano resonances are generated in the visible spectrum due to the destructive interference between the sub-radiant higher order modes and super-radiant the dipolar mode. The Fano resonances can be tuned by varying the cavity\\'s width and the rotation angle. An RLC circuit, which is mathematically equivalent to a mass-spring oscillator, is proposed to model the optical response of the nanostructure design.

  20. Electron beam induced coloration and luminescence in layered structure of WO3 thin films grown by pulsed dc magnetron sputtering

    International Nuclear Information System (INIS)

    Karuppasamy, A.; Subrahmanyam, A.

    2007-01-01

    Tungsten oxide thin films have been deposited by pulsed dc magnetron sputtering of tungsten in argon and oxygen atmosphere. The as-deposited WO 3 film is amorphous, highly transparent, and shows a layered structure along the edges. In addition, the optical properties of the as-deposited film show a steplike behavior of extinction coefficient. However, the electron beam irradiation (3.0 keV) of the as-deposited films results in crystallization, coloration (deep blue), and luminescence (intense red emission). The above changes in physical properties are attributed to the extraction of oxygen atoms from the sample and the structural modifications induced by electron bombardment. The present method of coloration and luminescence has a potential for fabricating high-density optical data storage device