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Sample records for gev-heavy ion irradiations

  1. Self-aligned nanostructures created by swift heavy ion irradiation

    SciTech Connect

    Gehrke, Hans-Gregor; Nix, Anne-Katrin; Hofsaess, Hans; Krauser, Johann; Trautmann, Christina; Weidinger, Alois

    2010-05-15

    In tetrahedral amorphous carbon (ta-C) swift heavy ions create conducting tracks of about 8 nm in diameter. To apply these nanowires and implement them into nanodevices, they have to be contacted and gated. In the present work, we demonstrate the fabrication of conducting vertical nanostructures in ta-C together with self-aligned gate electrodes. A multilayer assembly is irradiated with GeV heavy ions and subsequently exposed to several selective etching processes. The samples consist of a Si wafer as substrate covered by a thin ta-C layer. On top is deposited a SiN{sub x} film for insulation, a Cr layer as electrode, and finally a polycarbonate film as ion track template. Chemical track etching opens nanochannels in the polymer which are self-aligned with the conducting tracks in ta-C because they are produced by the same ions. Through the pores in the polymer template, the Cr and SiN{sub x} layers are opened by ion beam sputtering and plasma etching, respectively. The resulting structure consists of nanowires embedded in the insulating carbon matrix with a built in gate electrode and has potential application as gated field emission cathode.

  2. Nanoindentation on ion irradiated steels

    NASA Astrophysics Data System (ADS)

    Hosemann, P.; Vieh, C.; Greco, R. R.; Kabra, S.; Valdez, J. A.; Cappiello, M. J.; Maloy, S. A.

    2009-06-01

    Radiation induced mechanical property changes can cause major difficulties in designing systems operating in a radiation environment. Investigating these mechanical property changes in an irradiation environment is a costly and time consuming activity. Ion beam accelerator experiments have the advantage of allowing relatively fast and inexpensive materials irradiations without activating the sample but do in general not allow large beam penetration depth into the sample. In this study, the ferritic/martensitic steel HT-9 was processed and heat treated to produce one specimen with a large grained ferritic microstructure and further heat treated to form a second specimen with a fine tempered martensitic lath structure and exposed to an ion beam and tested after irradiation using nanoindentation to investigate the irradiation induced changes in mechanical properties. It is shown that the HT-9 in the ferritic heat treatment is more susceptible to irradiation hardening than HT-9 after the tempered martensitic heat treatment. Also at an irradiation temperature above 550 °C no detectable hardness increase due to irradiation was detected. The results are also compared to data from the literature gained from the fast flux test facility.

  3. Radioluminescence Investigation Of Ion-irradiated Phosphors

    SciTech Connect

    Jacobsohn, Luiz; Muenchausen, Ross; Bennett, Bryan

    2008-01-01

    Phosphors are materials that emit light under the excitation of incoming radiation. This property is used, among other applications, in radiation detection. Efficient energy transfer from the ionization track to the luminescent centers must occur to yield significant light output. Besides, the investigation of the effects of ion irradiation on the luminescence of phosphors is comparatively unexplored. In this work, we review radioluminescence (RL) investigation of ion-irradiated oxides and oxide phosphors, and present preliminary data on the effects of ion irradiation on the luminescence of intrinsic phosphor Bi{sub 4}Ge{sub 3}0{sub 12} (BGO). Commercial crystals were irradiated, and the irradiation effects characterized by means of RL measurements as a function of temperature, from 10K to room temperature (RT), and optical absorption measurements. Overall, surface modification induced by ion irradiation leads to higher luminescence output.

  4. Li + grafting of ion irradiated polyethylene

    NASA Astrophysics Data System (ADS)

    Švorčík, V.; Rybka, V.; Vacík, J.; Hnatowicz, V.; Öchsner, R.; Ryssel, H.

    1999-02-01

    Foils of oriented polyethylene (PE) were irradiated with 63 keV Ar + and 155 keV Xe + ions to different fluences at room temperature and then doped from water solution of LiCl. The as irradiated and irradiated plus doped samples were examined by IR, EPR and neutron depth profiling (NDP) technique. The sheet resistance was also measured by the standard two points method. After Li salt doping of ion modified layer of PE, a reaction between degraded macromolecules and Li occur and thus a new chemical structure C-Li + is formed. Owing to the presence of these cations on the polymer chain, the irradiated plus doped layer exhibits higher electric conductivity compared to as-irradiated ones.

  5. Ion irradiation effects on metallic nanocrystals

    NASA Astrophysics Data System (ADS)

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C. S.; Foran, G. J.; Cookson, D. J.; Byrne, A. P.; Ridgway, M. C.

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO2. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO2 interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  6. Ion irradiation effects on metallic nanocrystals

    SciTech Connect

    Kluth, P.; Johannessen, B.; Giulian, R.; Schnohr, C.S.; Foran, G.J.; Cookson, D.J.; Byrne, A.P.; Ridgway, M.C.

    2008-04-02

    We have investigated structural and morphological properties of metallic nanocrystals (NCs) exposed to ion irradiation. NCs were characterized by transmission electron microscopy in combination with advanced synchrotron-based analytical techniques, in particular X-ray absorption spectroscopy and small-angle X-ray scattering. A number of different effects were observed depending on the irradiation conditions. At energies where nuclear stopping is predominant, structural disorder/amorphization followed by inverse Ostwald ripening/dissolution due to ion beam mixing was observed for Au and Cu NCs embedded in SiO{sub 2}. The ion-irradiation-induced crystalline to amorphous transition in the NCs, which cannot be achieved in the corresponding bulk metals, was attributed to their initially higher structural energy as compared to bulk material and possibly preferential nucleation of the amorphous phase at the NC/SiO{sub 2} interface. At very high irradiation energies (swift heavy ion irradiation), where the energy loss is nearly entirely due to electronic stopping, a size-dependent shape transformation of the NCs from spheres to rod like shapes was apparent in Au NCs. Our preliminary results are in good agreement with considerations on melting of the NCs in the ion track as one mechanism involved in the shape transformation.

  7. Vibrational spectroscopy of ion-irradiated pentacene

    NASA Astrophysics Data System (ADS)

    Cannia, R.; Strazzulla, G.; Compagnini, G.; Baratta, G. A.

    1994-10-01

    In this paper we present a study of the evolution of the IR and Raman spectrum of pentacene before, during and after irradiation with energetic ion beams, demonstrating the complex chemistry induced by incoming ions. The formation of a "new" aromatic network has been evidenced. Dehydrogenation occurs and the evolution towards what we call an Ion Produced Hydrogenated Amorphous Carbon is a function of the ion dose as well. The results my have noteworthy relevance in astrophysics in view of the presently believed widespread presence of PAHs and their compounds in ours as well as other galaxies.

  8. In situ ion irradiation of zirconium carbide

    NASA Astrophysics Data System (ADS)

    Ulmer, Christopher J.; Motta, Arthur T.; Kirk, Mark A.

    2015-11-01

    Zirconium carbide (ZrC) is a candidate material for use in one of the layers of TRISO coated fuel particles to be used in the Generation IV high-temperature, gas-cooled reactor, and thus it is necessary to study the effects of radiation damage on its structure. The microstructural evolution of ZrCx under irradiation was studied in situ using the Intermediate Voltage Electron Microscope (IVEM) at Argonne National Laboratory. Samples of nominal stoichiometries ZrC0.8 and ZrC0.9 were irradiated in situ using 1 MeV Kr2+ ions at various irradiation temperatures (T = 20 K-1073 K). In situ experiments made it possible to continuously follow the evolution of the microstructure during irradiation using diffraction contrast imaging. Images and diffraction patterns were systematically recorded at selected dose points. After a threshold dose during irradiations conducted at room temperature and below, black-dot defects were observed which accumulated until saturation. Once created, the defect clusters did not move or get destroyed during irradiation so that at the final dose the low temperature microstructure consisted only of a saturation density of small defect clusters. No long-range migration of the visible defects or dynamic defect creation and elimination were observed during irradiation, but some coarsening of the microstructure with the formation of dislocation loops was observed at higher temperatures. The irradiated microstructure was found to be only weakly dependent on the stoichiometry.

  9. Cadmium Nanowire Formation Induced by Ion Irradiation

    SciTech Connect

    Jiang, Weilin; Weber, William J.; Wang, Chong M.; Young, James S.; Boatner, Lynn A.; Lian, Jie; Wang, Lumin; Ewing, Rodney C.

    2005-07-04

    One-dimensional nanostructures, such as nanowires, of semiconductors and metals are of great technological interest due to their potential for many advanced technology applications. Utilization of these materials versus their bulk counterparts will not only allow for device miniaturisation, but also may improve device performance or create new functions. Here we report a novel method for the synthesis of crystalline Cd-nanowires without involving either templates or a “seeded” structure. Ion irradiation at low temperatures (≤ 295 K) has been used to induce material decomposition and phase segregation in a cadmium niobate pyrochlore (Cd2Nb2O7) wafer. During the formation and rupture of the gas-filled blisters in the material, soft metallic Cd is extruded/extracted as nanowires through pores in the exfoliated layer. The entire process may be readily controlled by changing the ion irradiation conditions (e.g., ion species, dose and energy) with minimal thermal constraints.

  10. Swift Heavy Ion Irradiation of Cobalt Nanoparticles

    NASA Astrophysics Data System (ADS)

    Sprouster, D. J.; Giulian, R.; Schnohr, C. S.; Kluth, P.; Araujo, L. L.; Byrne, A. P.; Foran, G. J.; Ridgway, M. C.

    2009-01-01

    It is well known that the electronic energy loss released by swift heavy ions can cause considerable atomic movement in various solids. Here, we present a study of the effects of swift heavy ion irradiation on Co nanoparticles embedded within a silica host matrix. The evolution of the Co nanoparticle crystal phase, structural properties, shape and size has been characterized using a combination of x-ray absorption spectroscopy and transmission electron microscopy. An FCC-to-HCP phase transformation is observed at low fluences, while higher fluences result in significant changes in the short range order and NP shape. After an incubation fluence the nanoparticles deform into ellipsoids, preferentially aligned parallel to the incident beam direction. The threshold diameter for elongation was comparable to the saturation value of the ellipsoid width. We correlate this saturation value with the diameter of the molten track induced in amorphous silica by swift heavy ion irradiation.

  11. Chromosomal instability induced by heavy ion irradiation

    NASA Technical Reports Server (NTRS)

    Limoli, C. L.; Ponnaiya, B.; Corcoran, J. J.; Giedzinski, E.; Morgan, W. F.

    2000-01-01

    PURPOSE: To establish the dose-response relationship for the induction of chromosomal instability in GM10115 cells exposed to high-energy iron ions (1 GeV/nucleon, mean LET 146 keV/microm) and gold ions (11 GeV/nucleon, mean LET 1450 keV/microm). Past work has established that sparsely ionizing X-rays can induce a long-lived destabilization of chromosomes in a dose-dependent manner at an incidence of approximately 3% per gray. The present investigation assesses the capacity of High-Z and High-energy (HZE) particles to elicit this same endpoint. MATERIALS AND METHODS: Clonal populations derived from single progenitor cells surviving heavy-ion irradiation were analyzed cytogenetically to identify those clones showing a persistent destablization of chromosomes. RESULTS: Dose-response data, with a particular emphasis at low dose (< 1.0 Gy), indicate a frequency of approximately 4% per gray for the induction of chromosomal instability in clones derived from single progenitor cells surviving exposure to iron ions. The induction of chromosomal instability by gold ions was, however, less responsive to applied dose, as the observed incidence of this phenotype varied from 0 to 10% over 1-8 Gy. Both iron and gold ions gave dose-dependent increases in the yield of chromosomal aberrations (both chromosome- and chromatid-type) measured at the first mitosis following irradiation, as well as shoulderless survival curves having D0=0.87 and 1.1 Gy respectively. CONCLUSIONS: Based on the present dose-response data, the relative biological effectiveness of iron ions is 1.3 for the induction of chromosomal instability, and this indicates that heavy ions are only slightly more efficient than X-rays at eliciting this delayed phenotype.

  12. Mutation induced with ion beam irradiation in rose

    NASA Astrophysics Data System (ADS)

    Yamaguchi, H.; 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. Local brain heavy ion irradiation induced Immunosuppression

    NASA Astrophysics Data System (ADS)

    Lei, Runhong; Deng, Yulin; Huiyang Zhu, Bitlife.; Zhao, Tuo; Wang, Hailong; Yu, Yingqi; Ma, Hong; Wang, Xiao; Zhuang, Fengyuan; Qing, Hong

    Purpose: To investigate the long term effect of acute local brain heavy ion irradiation on the peripheral immune system in rat model. Methodology: Only the brain of adult male Wistar rats were radiated by heavy ions at the dose of 15 Gy. One, two and three months after irradiation, thymus and spleen were analyzed by four ways. Tunel assay was performed to evaluate the percentage of apoptotic cells in thymus and spleen, level of Inflammatory cytokines (IL-2, IL-6, SSAO, and TNF-α) was detected by ELISA assay, the differentiation of thymus T lymphocyte subsets were measured by flow cytometry and the relative expression levels of genes related to thymus immune cell development were measured by using quantitative real-time PCR. Results: Thymus and spleen showed significant atrophy from one month to three months after irradiation. A high level of apoptosis in thymus and spleen were obtained and the latter was more vulnerable, also, high level of inflammatory cytokines were found. Genes (c-kit, Rag1, Rag2 and Sca1) related to thymus lymphocytes’ development were down-regulated. Conclusion: Local area radiation in the rat brain would cause the immunosuppression, especially, the losing of cell-mediated immune functions. In this model, radiation caused inflammation and then induced apoptosis of cells in the immune organs, which contributed to immunosuppression.

  14. High temperature annealing of ion irradiated tungsten

    DOE PAGESBeta

    Ferroni, Francesco; Yi, Xiaoou; Arakawa, Kazuto; Fitzgerald, Steven P.; Edmondson, Philip D.; Roberts, Steve G.

    2015-03-21

    In this study, transmission electron microscopy of high temperature annealing of pure tungsten irradiated by self-ions was conducted to elucidate microstructural and defect evolution in temperature ranges relevant to fusion reactor applications (500–1200°C). Bulk isochronal and isothermal annealing of ion irradiated pure tungsten (2 MeV W+ ions, 500°C, 1014 W+/cm2) with temperatures of 800, 950, 1100 and 1400°C, from 0.5 to 8 h, was followed by ex situ characterization of defect size, number density, Burgers vector and nature. Loops with diameters larger than 2–3 nm were considered for detailed analysis, among which all loops had View the MathML source andmore » were predominantly of interstitial nature. In situ annealing experiments from 300 up to 1200°C were also carried out, including dynamic temperature ramp-ups. These confirmed an acceleration of loop loss above 900°C. At different temperatures within this range, dislocations exhibited behaviour such as initial isolated loop hopping followed by large-scale rearrangements into loop chains, coalescence and finally line–loop interactions and widespread absorption by free-surfaces at increasing temperatures. An activation energy for the annealing of dislocation length was obtained, finding Ea=1.34±0.2 eV for the 700–1100°C range.« less

  15. High temperature annealing of ion irradiated tungsten

    SciTech Connect

    Ferroni, Francesco; Yi, Xiaoou; Fitzgerald, Steven P.; Edmondson, Philip D.; Roberts, Steve G.

    2015-03-21

    In this study, transmission electron microscopy of high temperature annealing of pure tungsten irradiated by self-ions was conducted to elucidate microstructural and defect evolution in temperature ranges relevant to fusion reactor applications (500–1200°C). Bulk isochronal and isothermal annealing of ion irradiated pure tungsten (2 MeV W+ ions, 500°C, 1014 W+/cm2) with temperatures of 800, 950, 1100 and 1400°C, from 0.5 to 8 h, was followed by ex situ characterization of defect size, number density, Burgers vector and nature. Loops with diameters larger than 2–3 nm were considered for detailed analysis, among which all loops had View the MathML source and were predominantly of interstitial nature. In situ annealing experiments from 300 up to 1200°C were also carried out, including dynamic temperature ramp-ups. These confirmed an acceleration of loop loss above 900°C. At different temperatures within this range, dislocations exhibited behaviour such as initial isolated loop hopping followed by large-scale rearrangements into loop chains, coalescence and finally line–loop interactions and widespread absorption by free-surfaces at increasing temperatures. An activation energy for the annealing of dislocation length was obtained, finding Ea=1.34±0.2 eV for the 700–1100°C range.

  16. Enhanced adhesion from high energy ion irradiation

    NASA Technical Reports Server (NTRS)

    Werner, B. T.; Vreeland, T., Jr.; Mendenhall, M. H.; Qui, Y.; Tombrello, T. A.

    1983-01-01

    It has been found that the adhesion of thin metal films on insulators, semiconductors, and metals could be improved by subjecting the material to a high-energy ion bombardment. Griffith et al. (1982) have first suggested a use of this technique with insulators. The present investigation has the objective to determine the mechanism for the adhesion enhancement. A description is presented of a preliminary transmission electron microscopy (TEM) study of thinned bonded samples of silver on silicon using electron diffraction. It is found that irradiation of a variety of thin film-substrate combinations by heavy ion beams will provide a remarkable improvement in the adherence of the film. The evidence for the mechanism involved in the enhancement of adhesion is discussed.

  17. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation.

    PubMed

    Isozaki, Tetsuro; Fujita, Mayumi; Yamada, Shigeru; Imadome, Kaori; Shoji, Yoshimi; Yasuda, Takeshi; Nakayama, Fumiaki; Imai, Takashi; Matsubara, Hisahiro

    2016-07-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  18. Effects of carbon ion irradiation and X-ray irradiation on the ubiquitylated protein accumulation

    PubMed Central

    ISOZAKI, TETSURO; FUJITA, MAYUMI; YAMADA, SHIGERU; IMADOME, KAORI; SHOJI, YOSHIMI; YASUDA, TAKESHI; NAKAYAMA, FUMIAKI; IMAI, TAKASHI; MATSUBARA, HISAHIRO

    2016-01-01

    C-ion radiotherapy is associated with improved local control and survival in several types of tumors. Although C-ion irradiation is widely reported to effectively induce DNA damage in tumor cells, the effects of irradiation on proteins, such as protein stability or degradation in response to radiation stress, remain unknown. We aimed to compare the effects of C-ion and X-ray irradiation focusing on the cellular accumulation of ubiquitylated proteins. Cells from two human colorectal cancer cell lines, SW620 and SW480, were subjected to C-ion or X-ray irradiation and determination of ubiquitylated protein levels. High levels of ubiquitylated protein accumulation were observed in the C-ion-irradiated SW620 with a peak at 3 Gy; the accumulation was significantly lower in the X-ray-irradiated SW620 at all doses. Enhanced levels of ubiquitylated proteins were also detected in C-ion or X-ray-irradiated SW480, however, those levels were significantly lower than the peak detected in the C-ion-irradiated SW620. The levels of irradiation-induced ubiquitylated proteins decreased in a time-dependent manner, suggesting that the proteins were eliminated after irradiation. The treatment of C-ion-irradiated SW620 with a proteasome inhibitor (epoxomicin) enhanced the cell killing activity. The accumulated ubiquitylated proteins were co-localized with γ-H2AX, and with TP53BP1, in C-ion-irradiated SW620, indicating C-ion-induced ubiquitylated proteins may have some functions in the DNA repair system. Overall, we showed C-ion irradiation strongly induces the accumulation of ubiquitylated proteins in SW620. These characteristics may play a role in improving the therapeutic ratio of C-ion beams; blocking the clearance of ubiquitylated proteins may enhance sensitivity to C-ion radiation. PMID:27175736

  19. Hydrogen retention in ion irradiated steels

    SciTech Connect

    Hunn, J.D.; Lewis, M.B.; Lee, E.H.

    1998-11-01

    In the future 1--5 MW Spallation Neutron Source, target radiation damage will be accompanied by high levels of hydrogen and helium transmutation products. The authors have recently carried out investigations using simultaneous Fe/He,H multiple-ion implantations into 316 LN stainless steel between 50 and 350 C to simulate the type of radiation damage expected in spallation neutron sources. Hydrogen and helium were injected at appropriate energy and rate, while displacement damage was introduced by nuclear stopping of 3.5 MeV Fe{sup +}, 1 {micro}m below the surface. Nanoindentation measurements showed a cumulative increase in hardness as a result of hydrogen and helium injection over and above the hardness increase due to the displacement damage alone. TEM investigation indicated the presence of small bubbles of the injected gases in the irradiated area. In the current experiment, the retention of hydrogen in irradiated steel was studied in order to better understand its contribution to the observed hardening. To achieve this, the deuterium isotope ({sup 2}H) was injected in place of natural hydrogen ({sup 1}H) during the implantation. Trapped deuterium was then profiled, at room temperature, using the high cross-section nuclear resonance reaction with {sup 3}He. Results showed a surprisingly high concentration of deuterium to be retained in the irradiated steel at low temperature, especially in the presence of helium. There is indication that hydrogen retention at spallation neutron source relevant target temperatures may reach as high as 10%.

  20. Surface Modification of Polymer Substrates by Oxygen Ion Irradiation

    SciTech Connect

    Takaoka, G. H.; Ryuto, H.; Araki, R.; Yakushiji, T.

    2008-11-03

    Oxygen cluster ions and/or monomer ions were used for the sputtering and the surface modification of polymers such as polycarbonate (PC) and polyethylene terephthalate (PET). For the case of oxygen cluster ion irradiation, the sputtered depth increased with increase of the acceleration voltage, and the sputtering yield was much larger than that by the monomer ion irradiation. The sputtered particles represented the polymer structure, which indicated that the bond scission by the cluster ion irradiation resulted in an ejection of monomer molecule through the intermolecular collision. On the other hand, for the oxygen monomer ion irradiation, the implanted depth increased with increase of the acceleration voltage, and the bond scission occurred at the deep region through the binary collision with the high energetic ions. Therefore, the sputtering yield for the polymer surfaces decreased, and the sputtering effect became very small. Furthermore, the simultaneous use of oxygen cluster and monomer ions was more effective for oxidation of the PET surfaces rather than the monomer ion irradiation or the cluster ion irradiation. As a result, the contact angle measurement showed that the wettability of the PET surfaces irradiated by the simultaneous use of oxygen cluster and monomer ions was much enhanced.

  1. Modification on graphite due to helium ion irradiation

    NASA Astrophysics Data System (ADS)

    Dutta, N. J.; Mohanty, S. R.; Buzarbaruah, N.

    2016-07-01

    This paper studies the influence of helium ion irradiation on morphological and structural properties of graphite samples. The helium ions emanated from a plasma focus device have been used to irradiate graphite samples by varying the number of ion pulses. The effect of radiation induced changes in morphology and structure are examined by using optical microscopy, atomic force microscopy, transmission electron microscopy along with selected area electron diffraction and x-ray diffraction. A distinct change in the surface topography is marked in the case of the ion irradiated samples when viewed under the optical microscope. The micrographs of the ion irradiated samples confirm mostly rounded and sparely elongated type of structures arising due to intense melting and local ablation accompanied with ejection of graphite melts that depends upon the ion fluence. The atomic force microscopy images also reveal the formation of globules having sizes ∼50-200 nm which are the agglomeration of small individual clusters. Transmission electron micrographs of the ion irradiated samples furnish that the diameter of these individual small clusters are ∼10.4 nm. Moreover, selected area electron diffraction patterns corroborate that the ion irradiated sample retains its crystalline nature, even after exposure to larger helium ion pulses. It is noticed from the x-ray diffraction patterns that some new phases are developed in the case of ion irradiated sample.

  2. Graphitization of polymer surfaces by scanning ion irradiation

    SciTech Connect

    Koval, Yuri

    2014-10-20

    Graphitization of polymer surfaces was performed by low-energy Ar{sup +} and He{sup +} ion irradiation. A method of scanning irradiation was implemented. It was found that by scanning ion irradiation, a significantly higher electrical conductivity in the graphitized layers can be achieved in comparison with a conventional broad-beam irradiation. The enhancement of the conductance becomes more pronounced for narrower and better collimated ion beams. In order to analyze these results in more detail, the temperature dependence of conductance of the irradiated samples was investigated. The results of measurements are discussed in terms of weak localization corrections to conductance in disordered metals. The observed effects can be explained by enlargement of graphitic patches, which was achieved with the scanning ion irradiation method.

  3. Spectroscopic characterization of ion-irradiated multi-layer graphenes

    NASA Astrophysics Data System (ADS)

    Tsukagoshi, Akira; Honda, Shin-ichi; Osugi, Ryo; Okada, Hiraku; Niibe, Masahito; Terasawa, Mititaka; Hirase, Ryuji; Izumi, Hirokazu; Yoshioka, Hideki; Niwase, Keisuke; Taguchi, Eiji; Lee, Kuei-Yi; Oura, Masaki

    2013-11-01

    Low-energy Ar ions (0.5-2 keV) were irradiated to multi-layer graphenes and the damage process, the local electronic states, and the degree of alignment of the basal plane, and the oxidation process upon ion irradiation were investigated by Raman spectroscopy, soft X-ray absorption spectroscopy (XAS) and in situ X-ray photoelectron spectroscopy (XPS). By Raman spectroscopy, we observed two stages similar to the case of irradiated graphite, which should relate to the accumulations of vacancies and turbulence of the basal plane, respectively. XAS analysis indicated that the number of sp2-hybridized carbon (sp2-C) atoms decreased after ion irradiation. Angle-resolved XAS revealed that the orientation parameter (OP) decreased with increasing ion energy and fluence, reflecting the turbulence of the basal plane under irradiation. In situ XPS shows the oxidation of the irradiated multi-layer graphenes after air exposure.

  4. Concurrent in situ ion irradiation transmission electron microscope

    DOE PAGESBeta

    Hattar, K.; Bufford, D. C.; Buller, D. L.

    2014-08-29

    An in situ ion irradiation transmission electron microscope has been developed and is operational at Sandia National Laboratories. This facility permits high spatial resolution, real time observation of electron transparent samples under ion irradiation, implantation, mechanical loading, corrosive environments, and combinations thereof. This includes the simultaneous implantation of low-energy gas ions (0.8–30 keV) during high-energy heavy ion irradiation (0.8–48 MeV). In addition, initial results in polycrystalline gold foils are provided to demonstrate the range of capabilities.

  5. Emulation of reactor irradiation damage using ion beams

    DOE PAGESBeta

    Was, G. S.; Jiao, Z.; Getto, E.; Sun, K.; Monterrosa, A. M.; Maloy, S. A.; Anderoglu, O.; Sencer, B. H.; Hackett, M.

    2014-06-14

    The continued operation of existing light water nuclear reactors and the development of advanced nuclear reactor depend heavily on understanding how damage by radiation to levels degrades materials that serve as the structural components in reactor cores. The first high dose ion irradiation experiments on a ferritic-martensitic steel showing that ion irradiation closely emulates the full radiation damage microstructure created in-reactor are described. Ferritic-martensitic alloy HT9 (heat 84425) in the form of a hexagonal fuel bundle duct (ACO-3) accumulated 155 dpa at an average temperature of 443°C in the Fast Flux Test Facility (FFTF). Using invariance theory as a guide,more » irradiation of the same heat was conducted using self-ions (Fe++) at 5 MeV at a temperature of 460°C and to a dose of 188 displacements per atom. The void swelling was nearly identical between the two irradiation and the size and density of precipitates and loops following ion irradiation are within a factor of two of those for neutron irradiation. The level of agreement across all of the principal microstructure changes between ion and reactor irradiation establishes the capability of tailoring ion irradiation to emulate the reactor-irradiated microstructure.« less

  6. Emulation of reactor irradiation damage using ion beams

    SciTech Connect

    Was, G. S.; Jiao, Z.; Getto, E.; Sun, K.; Monterrosa, A. M.; Maloy, S. A.; Anderoglu, O.; Sencer, B. H.; Hackett, M.

    2014-06-14

    The continued operation of existing light water nuclear reactors and the development of advanced nuclear reactor depend heavily on understanding how damage by radiation to levels degrades materials that serve as the structural components in reactor cores. The first high dose ion irradiation experiments on a ferritic-martensitic steel showing that ion irradiation closely emulates the full radiation damage microstructure created in-reactor are described. Ferritic-martensitic alloy HT9 (heat 84425) in the form of a hexagonal fuel bundle duct (ACO-3) accumulated 155 dpa at an average temperature of 443°C in the Fast Flux Test Facility (FFTF). Using invariance theory as a guide, irradiation of the same heat was conducted using self-ions (Fe++) at 5 MeV at a temperature of 460°C and to a dose of 188 displacements per atom. The void swelling was nearly identical between the two irradiation and the size and density of precipitates and loops following ion irradiation are within a factor of two of those for neutron irradiation. The level of agreement across all of the principal microstructure changes between ion and reactor irradiation establishes the capability of tailoring ion irradiation to emulate the reactor-irradiated microstructure.

  7. Bromate ion removal by HEEB irradiation

    SciTech Connect

    Siddiqui, M.S.; Amy, G.L.; Cooper, W.J.; Nickelsen, M.G.; Kurucz, C.N.; Waite, T.D.

    1996-10-01

    Proposed drinking water regulations will specify a maximum contaminant level of 0.01 mg/L for bromate ion (BrO{sub 3}{sup {minus}}). This study used high-energy electron-beam irradiation to remove BrO{sub 3}{sup {minus}} after formation, when other control strategies are not as effective. BrO{sub 3}{sup {minus}} was reduced to bromide ion (Br{sup {minus}}), with bromine (HOBr/OBr{sup {minus}}) as intermediate. A dose of 60 krads was sufficient to reduce 70 percent of BrO{sub 3}{sup {minus}} from an initial concentration of 100 {micro}g/L. The presence of electron scavengers such as hydrogen peroxide and nitrate significantly reduced BrO{sub 3}{sup {minus}} removal, whereas the addition of the OH radical scavenger such as t-butanol did not affect the removal of BrO{sub 3}{sup {minus}}. This indicates that aqueous electrons (e{sub aq}{sup {minus}}) are mainly responsible for BrO{sub 3}{sup {minus}} destruction. The presence of natural organic matter decreased BrO{sub 3}{sup {minus}} reduction efficiency. The reaction of e{sub aq}{sup {minus}} with various bromine species in water was used to model and simulate experimental data for the destruction of BrO{sub 3}{sup {minus}}. Computer model predictions were in fairly good agreement with the experimental results.

  8. Mechanical property measurements on ion-irradiated metals

    SciTech Connect

    Zinkle, S.J.; Oliver, W.C.

    1986-08-01

    A recently developed mechanical properties microprobe (MPM) has been used to investigate strength and elastic modulus changes in ion-irradiated metals. The indenter load and its displacement are simultaneously monitored while the indentation is being made and also during unloading. Microindentation hardness measurements have been performed on ion-irradiated copper and Cu-0.15% Zr (AMZIRC). The depth dependence of the ion damage has been investigated in selected specimens which were prepared using a cross-section technique. This procedure allows a direct comparison to be made of hardness data from different irradiation depths while the indent size is held constant. The displacement damage associated with ion irradiation caused either hardening or softening, depending on the irradiation conditions and the material.

  9. Enhanced electrochemical etching of ion irradiated silicon by localized amorphization

    SciTech Connect

    Dang, Z. Y.; Breese, M. B. H.; Lin, Y.; Tok, E. S.; Vittone, E.

    2014-05-12

    A tailored distribution of ion induced defects in p-type silicon allows subsequent electrochemical anodization to be modified in various ways. Here we describe how a low level of lattice amorphization induced by ion irradiation influences anodization. First, it superposes a chemical etching effect, which is observable at high fluences as a reduced height of a micromachined component. Second, at lower fluences, it greatly enhances electrochemical anodization by allowing a hole diffusion current to flow to the exposed surface. We present an anodization model, which explains all observed effects produced by light ions such as helium and heavy ions such as cesium over a wide range of fluences and irradiation geometries.

  10. Enhanced electrochemical etching of ion irradiated silicon by localized amorphization

    NASA Astrophysics Data System (ADS)

    Dang, Z. Y.; Breese, M. B. H.; Lin, Y.; Tok, E. S.; Vittone, E.

    2014-05-01

    A tailored distribution of ion induced defects in p-type silicon allows subsequent electrochemical anodization to be modified in various ways. Here we describe how a low level of lattice amorphization induced by ion irradiation influences anodization. First, it superposes a chemical etching effect, which is observable at high fluences as a reduced height of a micromachined component. Second, at lower fluences, it greatly enhances electrochemical anodization by allowing a hole diffusion current to flow to the exposed surface. We present an anodization model, which explains all observed effects produced by light ions such as helium and heavy ions such as cesium over a wide range of fluences and irradiation geometries.

  11. Ion irradiation testing of Improved Accident Tolerant Cladding Materials

    SciTech Connect

    Anderoglu, Osman; Tesmer, Joseph R.; Maloy, Stuart A.

    2014-01-14

    This report summarizes the results of ion irradiations conducted on two FeCrAl alloys (named as ORNL A&B) for improving the accident tolerance of LWR nuclear fuel cladding. After irradiation with 1.5 MeV protons to ~0.5 to ~1 dpa and 300°C nanoindentations were performed on the cross-sections along the ion range. An increase in hardness was observed in both alloys. Microstructural analysis shows radiation induced defects.

  12. Heavy-ion irradiation induced diamond formation in carbonaceous materials.

    SciTech Connect

    Daulton, T. L.

    1999-01-08

    The basic mechanisms of metastable phase formation produced under highly non-equilibrium thermodynamic conditions within high-energy particle tracks are investigated. In particular, the possible formation of diamond by heavy-ion irradiation of graphite at ambient temperature is examined. This work was motivated, in part, by earlier studies which discovered nanometer-grain polycrystalline diamond aggregates of submicron-size in uranium-rich carbonaceous mineral assemblages of Precambrian age. It was proposed that the radioactive decay of uranium formed diamond in the fission particle tracks produced in the carbonaceous minerals. To test the hypothesis that nanodiamonds can form by ion irradiation, fine-grain polycrystalline graphite sheets were irradiated with 400 MeV Kr ions. The ion irradiated graphite (and unirradiated graphite control) were then subjected to acid dissolution treatments to remove the graphite and isolate any diamonds that were produced. The acid residues were then characterized by analytical and high-resolution transmission electron microscopy. The acid residues of the ion-irradiated graphite were found to contain ppm concentrations of nanodiamonds, suggesting that ion irradiation of bulk graphite at ambient temperature can produce diamond.

  13. The effects of swift heavy-ion irradiation on helium-ion-implanted silicon

    NASA Astrophysics Data System (ADS)

    Li, B. S.; Du, Y. Y.; Wang, Z. G.; Shen, T. L.; Li, Y. F.; Yao, C. F.; Sun, J. R.; Cui, M. H.; Wei, K. F.; Zhang, H. P.; Shen, Y. B.; Zhu, Y. B.; Pang, L. L.

    2014-10-01

    Cross-sectional transmission electron microscopy (XTEM) was used to study the effects of irradiation with swift heavy ions on helium-implanted silicon. <1 0 0>-oriented silicon wafers were implanted with 30 keV helium to a dose of 3 × 1016 He+/cm2 at 600 K. Subsequently, the helium-implanted Si wafers were irradiated with 792 MeV argon ions. The He bubbles and extended defects in the wafers were examined via XTEM analysis. The results reveal that the mean diameter of the He bubbles increases upon Ar-ion irradiation, while the number density of the He bubbles decreases. The microstructure of the He bubbles observed after Ar-ion irradiation is comparable to that observed after annealing at 1073 K for 30 min. Similarly, the mean size of the extended defects, i.e., Frank loops, increases after Ar-ion irradiation. Possible mechanisms are discussed.

  14. Neurite outgrowth on fluorinated polyimide film micropatterned by ion irradiation

    NASA Astrophysics Data System (ADS)

    Okuyama, Y.; Sato, M.; Nagaoka, S.; Kawakami, H.; Suzuki, Y.; Iwaki, M.

    2003-05-01

    In this study, we investigated neurite outgrowth on a fluorinated polyimide film micropatterned by ion irradiation. We used the fluorinated polyimide because of its excellent thermal and mechanical properties and biocompatibility. Rattus norvegicus chromaphin (PC12) cells were used for in vitro studies. The polyimide films were irradiated with He +, Ne + or Kr + at 1 × 10 14 ions/cm 2 using an ion-beam mask. The lines in the mask were 120 and 160 μm wide and 120-160 μm apart. PC12 cells were selectively adhered on the polyimide film micropatterned by Kr +-irradiation. However, the neurite length on the film irradiated by Kr + was shorter than that determined in the film irradiated by He +. On the other hand, neurite outgrowth on the polyimide film micropatterned by He +-irradiation was at least 100 μm in length. This initial study indicated the enhanced outgrowth of PC12 cells on the fluorinated polyimide film micropatterned by ion irradiation.

  15. Sputtering of HOPG under high-dose ion irradiation

    NASA Astrophysics Data System (ADS)

    Borisov, A. M.; Mashkova, E. S.; Nemov, A. S.; Virgiliev, Yu. S.

    2007-03-01

    The dependences of sputtering yield Y of highly oriented pyrolytic graphite under high fluences (1018-1019 ion/cm2) 30 keV N2+ irradiation at ion incidence angles from θ = 0 (normal incidence) to θ = 80° at room temperature (RT) and T = 400 °C have been measured to trace the radiation damage influence on angular behavior of sputtering yield. A difference has been found between angular dependences of sputtering yields at RT, when the irradiation leads to a high degree of disorder, and at temperatures, larger than the temperature Ta responsible for annealing the radiation damage at continuous ion bombardment.

  16. Anomalous Plastic Deformation and Sputtering of Ion Irradiated Silicon Nanowires

    PubMed Central

    2015-01-01

    Silicon nanowires of various diameters were irradiated with 100 keV and 300 keV Ar+ ions on a rotatable and heatable stage. Irradiation at elevated temperatures above 300 °C retains the geometry of the nanostructure and sputtering can be gauged accurately. The diameter dependence of the sputtering shows a maximum if the ion range matches the nanowire diameter, which is in good agreement with Monte Carlo simulations based on binary collisions. Nanowires irradiated at room temperature, however, amorphize and deform plastically. So far, plastic deformation has not been observed in bulk silicon at such low ion energies. The magnitude and direction of the deformation is independent of the ion-beam direction and cannot be explained with mass-transport in a binary collision cascade but only by collective movement of atoms in the collision cascade with the given boundary conditions of a high surface to volume ratio. PMID:25951108

  17. Characterization of swift heavy ion irradiation damage in ceria

    SciTech Connect

    Yablinsky, Clarissa; Devanathan, Ram; Pakarinen, Janne; Gan, Jian; Severin, Daniel; Trautmann, Christina; Allen, T. R.

    2015-05-14

    We have examined microstructural evolution in irradiated ceria (CeO2) using swift heavy ion irradiation, electron microscopy, and atomistic simulation. CeO2, a UO2 fuel surrogate, was irradiated with gold ions at an energy of 1 GeV to fluences up to 1x1014 ions/cm2. Transmission electron microscopy accompanied by electron energy loss spectroscopy showed that the ion tracks were of similar size at all fluences, and that there was no chemical change in the ion track core. Classical molecular dynamics simulations of thermal spikes in CeO2 with energy deposition of 12 and 36 keV/nm show damage consisting of isolated point defects at the lower energy and defect clusters at 36 keV/nm, with no amorphization at either energy. Inferences are drawn from modeling about density changes in the ion track and the formation of interstitial loops that shed light on features observed by electron microscopy of swift heavy ion irradiated ceria.

  18. University of Wisconsin Ion Beam Laboratory: A facility for irradiated materials and ion beam analysis

    SciTech Connect

    Field, K. G.; Wetteland, C. J.; Cao, G.; Maier, B. R.; Gerczak, T. J.; Kriewaldt, K.; Sridharan, K.; Allen, T. R.; Dickerson, C.; Field, C. R.

    2013-04-19

    The University of Wisconsin Ion Beam Laboratory (UW-IBL) has recently undergone significant infrastructure upgrades to facilitate graduate level research in irradiated materials phenomena and ion beam analysis. A National Electrostatics Corp. (NEC) Torodial Volume Ion Source (TORVIS), the keystone upgrade for the facility, can produce currents of hydrogen ions and helium ions up to {approx}200 {mu}A and {approx}5 {mu}A, respectively. Recent upgrades also include RBS analysis packages, end station developments for irradiation of relevant material systems, and the development of an in-house touch screen based graphical user interface for ion beam monitoring. Key research facilitated by these upgrades includes irradiation of nuclear fuels, studies of interfacial phenomena under irradiation, and clustering dynamics of irradiated oxide dispersion strengthened steels. The UW-IBL has also partnered with the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) to provide access to the irradiation facilities housed at the UW-IBL as well as access to post irradiation facilities housed at the UW Characterization Laboratory for Irradiated Materials (CLIM) and other ATR-NSUF partner facilities. Partnering allows for rapid turnaround from proposed research to finalized results through the ATR-NSUF rapid turnaround proposal system. An overview of the UW-IBL including CLIM and relevant research is summarized.

  19. Dislocation loop evolution under ion irradiation in austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Etienne, A.; Hernández-Mayoral, M.; Genevois, C.; Radiguet, B.; Pareige, P.

    2010-05-01

    A solution annealed 304 and a cold worked 316 austenitic stainless steels were irradiated from 0.36 to 5 dpa at 350 °C using 160 keV Fe ions. Irradiated microstructures were characterized by transmission electron microscopy (TEM). Observations after irradiation revealed the presence of a high number density of Frank loops. Size and number density of Frank loops have been measured. Results are in good agreement with those observed in the literature and show that ion irradiation is able to simulate dislocation loop microstructure obtained after neutron irradiation. Experimental results and data from literature were compared with predictions from the cluster dynamic model, MFVIC (Mean Field Vacancy and Interstitial Clustering). It is able to reproduce dislocation loop population for neutron irradiation. Effects of dose rate and temperature on the loop number density are simulated by the model. Calculations for ion irradiations show that simulation results are consistent with experimental observations. However, results also show the model limitations due to the lack of accurate parameters.

  20. Raman measurements in silica glasses irradiated with energetic ions

    SciTech Connect

    Saavedra, R. Martin, P.; Vila, R.; León, M.; Jiménez-Rey, D.; Girard, S.; Boukenter, A.; Ouerdane, Y.

    2014-10-21

    Ion irradiation with energetic He{sup +} (2.5 MeV), O{sup 4+} (13.5 MeV), Si{sup 4+} (24.4 MeV) and Cu{sup 7+} (32.6 MeV) species at several fluences (from 5 × 10{sup 12} to 1.65 × 10{sup 15} ion/cm{sup 2}) were performed in three types of SiO{sub 2} glasses with different OH content (KU1, KS-4V and Infrasil 301). After ion implantation the Raman spectra were measured and compared with the spectra of unirradiated samples. Irradiated samples of the three fused silica grades exhibit changes in the broad and asymmetric R-band (ω{sub 1} around 445 cm{sup −1}), in D{sub 1} (490 cm−1) and D{sub 2} (605 cm{sup −1}) bands associated to small-membered rings. The D{sub 2} band shows an increase with increasing fluences for different ions, indicating structural changes. Raman spectra of ion-irradiated samples were compared with the spectra of neutron irradiated samples at fluences 10{sup 17} n/cm{sup 2} and 1018 n/cm{sup 2}. Macroscopic surface cracking was detected, mainly at fluences corresponding to deposited energies between 10{sup 23} eV/cm{sup 3} and 10{sup 24} eV/cm{sup 3} (after ion beam shutdown)

  1. Amorphization of embedded Cu nanocrystals by ion irradiation

    NASA Astrophysics Data System (ADS)

    Johannessen, B.; Kluth, P.; Llewellyn, D. J.; Foran, G. J.; Cookson, D. J.; Ridgway, M. C.

    2007-02-01

    While bulk crystalline elemental metals cannot be amorphized by ion irradiation in the absence of chemical impurities, the authors demonstrate that finite-size effects enable the amorphization of embedded Cu nanocrystals. The authors form and compare the atomic-scale structure of the polycrystalline, nanocrystalline, and amorphous phases, present an explanation for the extreme sensitivity to irradiation exhibited by nanocrystals, and show that low-temperature annealing is sufficient to return amorphized material to the crystalline form.

  2. Reduction and structural modification of zirconolite on He+ ion irradiation

    NASA Astrophysics Data System (ADS)

    Gupta, Merry; Kulriya, P. K.; Shukla, Rishabh; Dhaka, R. S.; Kumar, Raj; Ghumman, S. S.

    2016-07-01

    The immobilization of minor actinides and alkaline-earth metal is a major concern in nuclear industry due to their long-term radioactive contribution to the high level waste (HLW). Materials having zirconolite, pyrochlore, and perovskite structure are promising candidates for immobilization of HLW. The zirconolite which exhibits high radiation stability and corrosion resistance behavior is investigated for its radiation stability against alpha particles in the present study. CaZrTi2O7 pellets prepared using solid state reaction techniques, were irradiated with 30 keV He+ ions for the ion fluence varying from 1 × 1017 to 1 × 1021 ions/m2. Scanning electron microscopy (SEM) images of the un-irradiated sample exhibited well separated grains with average size of about 6.8 μm. On the ion irradiation, value of the average grains size was about 7.1 μm, and change in the microstructure was insignificant. The X-ray photoelectron spectroscopy (XPS) studies showed a shift in the core level peak position (of Ca 2p, Ti 2p and Zr 3d) towards lower binding energy with respect to pristine sample as well as loss of oxygen was also observed for sample irradiated with the ion fluence of 1 × 1020 ions/m2. These indicate a decrease in co-ordination number and the ionic character of Msbnd O bond. Moreover, core level XPS signal was not detected for sample irradiated with ion fluence of 1 × 1021 ions/m2, suggesting surface damage of the sample at this ion fluence. However, X-ray diffraction (XRD) studies showed that zirconolite was not amorphized even on irradiation up to a fluence order of 1 × 1021 ion/m2. But, significant decrease in peak intensity due to creation of defects and a marginal positive peak shift due to tensile strain induced by irradiation, were observed. Thus, XRD along with XPS investigation suggests that reduction, decrease in co-ordination number, and increase in covalency are responsible for the radiation damage in zirconolite.

  3. Ion irradiation of ammonia/carbon dioxide mixtures

    NASA Astrophysics Data System (ADS)

    Lv, X. Y.; Boduch, P.; Ding, J. J.; Domaracka, A.; Langlinay, T.; Palumbo, M. E.; Rothard, H.; Strazzulla, G.

    2013-09-01

    We present new experimental results on the thermal and ion irradiation processing of ammonia/carbon dioxide frozen mixtures. Mixtures deposited at low T (16 K) have then been warmed up to 160 K. During warm up complex chemical reactions occur leading to the formation of new molecules and, in particular, of ammonium carbamate. Other samples have been irradiated with 144 keV S9+ ions. Also in this case new chemical species are formed among which CO and OCN-. The results are discussed in the light of their relevance to understand the effects of different processes going on in the variegated superficial and sub-superficial layers of Enceladus.

  4. Surface modification of multilayer graphene using Ga ion irradiation

    SciTech Connect

    Wang, Quan; Shao, Ying; Ge, Daohan; Ren, Naifei; Yang, Qizhi

    2015-04-28

    The effect of Ga ion irradiation intensity on the surface of multilayer graphene was examined. Using Raman spectroscopy, we determined that the irradiation caused defects in the crystal structure of graphene. The density of defects increased with the increase in dwell times. Furthermore, the strain induced by the irradiation changed the crystallite size and the distance between defects. These defects had the effect of doping the multilayer graphene and increasing its work function. The increase in work function was determined using contact potential difference measurements. The surface morphology of the multilayer graphene changed following irradiation as determined by atomic force microscopy. Additionally, the adhesion between the atomic force microscopy tip and sample increased further indicating that the irradiation had caused surface modification, important for devices that incorporate graphene.

  5. Diamond structure recovery during ion irradiation at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Deslandes, Alec; Guenette, Mathew C.; Belay, Kidane; Elliman, Robert G.; Karatchevtseva, Inna; Thomsen, Lars; Riley, Daniel P.; Lumpkin, Gregory R.

    2015-12-01

    CVD diamond is irradiated by 5 MeV carbon ions, with each sample held at a different temperature (300-873 K) during irradiations. The defect structures resulting from the irradiations are evident as vacancy, interstitial and amorphous carbon signals in Raman spectra. The observed variation of the full width at half maximum (FWHM) and peak position of the diamond peak suggests that disorder in the diamond lattice is reduced for high temperature irradiations. The dumbbell interstitial signal is reduced for irradiations at 873 K, which suggests this defect is unstable at these temperatures and that interstitials have migrated to crystal surfaces. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy results indicate that damage to the diamond structure at the surface has occurred for room temperature irradiations, however, this structure is at least partially recovered for irradiations performed at 473 K and above. The results suggest that, in a high temperature irradiation environment such as a nuclear fusion device, in situ annealing of radiation-created defects can maintain the diamond structure and prolong the lifetime of diamond components.

  6. Tailoring the properties of copper nanowires by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Kumar, Narinder; Kumar, Rajesh; Kumar, Sushil; Chakarvarti, S. K.

    2016-02-01

    In the present paper, we investigated the change in the properties of copper nanowires under the irradiance of 80 MeV Si7+ ion beam. The nanowires were electrodeposited in the cylindrical pores of the track-etched polycarbonate membranes. The phase, morphology and optical absorbance of the fabricated nanowires were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible spectroscopy, respectively. The XRD study showed a face centered cubic crystal structure of copper nanowires. Further measurements with FESEM revealed that nanowires were continuous, aligned with uniform diameter having high aspect ratio. The XRD spectra of irradiated nanowires indicated an improved crystalinity at low ion fluences while it declines at higher ion fluences. The optical absorbance properties of the irradiated copper nanowires were also examined. The absorption spectra exhibited a peak at 568 nm which was attributed to the surface plasmon resonance. A significant increase in absorbance after irradiation accounts for the possibility of defects formation. The electrical properties measured from I-V characteristics showed an increase in resistivity of irradiated nanowires.

  7. Effects of Ga ion-beam irradiation on monolayer graphene

    NASA Astrophysics Data System (ADS)

    Wang, Quan; Mao, Wei; Ge, Daohan; Zhang, Yanmin; Shao, Ying; Ren, Naifei

    2013-08-01

    The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

  8. Effects of Ga ion-beam irradiation on monolayer graphene

    SciTech Connect

    Wang, Quan; Mao, Wei; Zhang, Yanmin; Shao, Ying; Ren, Naifei; Ge, Daohan

    2013-08-12

    The effects of Ga ion on the single layer graphene (SLG) have been studied by Raman spectroscopy (RS), SEM, and field-effect characterization. Under vacuum conditions, Ga ion-irradiation can induce disorders and cause red shift of 2D band of RS, rather than lattice damage in high quality SLG. The compressive strain induced by Ga ion decreases the crystalline size in SLG, which is responsible for the variation of Raman scattering and electrical properties. Nonlinear out-put characteristic and resistance increased are also found in the I-V measurement. The results have important implications during CVD graphene characterization and related device fabrication.

  9. Gel behavior of keV ion irradiated polystyrene

    SciTech Connect

    Calcagno, L.; Foti, G.; Licciardello, A.; Puglisi, O.

    1988-10-17

    Among the chemical and physical modifications induced by ion bombardment of polymers, the solubility changes are very important because of technological application for lithography in microelectronic devices. Solubility changes due to the occurrence of crosslinkings have been followed on monodisperse and polydisperse polystyrene after ion irradiations (10/sup 11/--10/sup 14/ ions/cm/sup 2/, keV energy). By using the Inokuty gel theory (M. Inokuti J. Appl. Phys. 38, 2999 (1963)), the chemical yield (crosslinking/eV) has been determined for different molecular weights and molecular weight distributions.

  10. Irradiation hardening of ODS ferritic steels under helium implantation and heavy-ion irradiation

    NASA Astrophysics Data System (ADS)

    Zhang, Hengqing; Zhang, Chonghong; Yang, Yitao; Meng, Yancheng; Jang, Jinsung; Kimura, Akihiko

    2014-12-01

    Irradiation hardening of ODS ferritic steels after multi-energy He-ion implantation, or after irradiation with energetic heavy ions including Xe and Bi-ions was investigated with nano-indentation technique. Three kinds of high-Cr ODS ferritic steels including the commercial MA956 (19Cr-3.5Al), the 16Cr-0.1Ti and the 16Cr-3.5Al-0.1Zr were used. Data of nano-hardness were analyzed with an approach based on Nix-Gao model. The depth profiles of nano-hardness can be understood by the indentation size effect (ISE) in specimens of MA956 implanted with multi-energy He-ions or irradiated with 328 MeV Xe ions, which produced a plateau damage profile in the near-surface region. However, the damage gradient overlaps the ISE in the specimens irradiated with 9.45 Bi ions. The dose dependence of the nano-hardness shows a rapid increase at low doses and a slowdown at higher doses. An 1/2-power law dependence on dpa level is obtained. The discrepancy in nano-hardness between the helium implantation and Xe-ion irradiation can be understood by using the average damage level instead of the peak dpa level. Helium-implantation to a high dose (7400 appm/0.5 dpa) causes an additional hardening, which is possibly attributed to the impediment of motion dislocations by helium bubbles formed in high concentration in specimens.

  11. Ion irradiation effects on the exchange bias in IrMn/Co films

    SciTech Connect

    Schafer, D.; Grande, P. L.; Pereira, L. G.; Geshev, J.

    2011-01-15

    The present work reports on the influence of ion irradiation in exchange-coupled bilayers. Magnetron-sputtered IrMn{sub 4}/Co films were irradiated with 40 keV He{sup +} ions and the dependence of their magnetic properties was studied as function of ion fluence and current used during the irradiations. The effects of ion damage and electronic excitation were also studied through additional irradiations with H{sup +} and Ne{sup +} ions. The results show a clear dependence of the exchange-bias field on the defects caused by the ion bombardment. No correlations with other irradiation effects were observed.

  12. Micromechanical tests of ion irradiated materials: Atomistic simulations and experiments

    SciTech Connect

    Shin, C.; Jin, H. H.; Kwon, J.

    2012-07-01

    We investigated irradiation effects on Fe-Cr binary alloys by using a nano-indentation combined with a continuous stiffness measurement (CSM) technique. We modeled the nano-indentation test by using a finite element method. We could extract the intrinsic hardness and the yield stress of an irradiation hardened region by using a so-called inverse method. SiC micro-pillars of various sizes were fabricated by mask and inductively coupled plasma etching technique and compressed by using flat punch nano-indentation. Compressive fracture strength showed a clear specimen size effect. Brittle-to-Ductile transition at room temperature was observed as the specimen size decreases. The effect of irradiation on the fracture strength of SiC micro-pillars was evaluated by performing ion irradiation with Si ions. We have performed molecular dynamics simulations of nano-indentation and nano-pillar compression tests. Radiation effect was observed which is found to be due to the interaction of dislocations nucleated by spherical indenter with pre-existing radiation defects (voids). These atomistic simulations are expected to significantly contribute to the investigation of the fundamental deformation mechanism of small scale irradiated materials. (authors)

  13. Characterization of swift heavy ion irradiation damage in ceria

    SciTech Connect

    Yablinsky, Clarissa A.; Devanathan, Ram; Pakarinen, Janne; Gan, Jian; Severin, Daniel; Trautmann, Christina; Allen, Todd R.

    2015-03-04

    Swift heavy ion induced radiation damage is investigated for ceria (CeO2), which serves as a UO2 fuel surrogate. Microstructural changes resulting from an irradiation with 940 MeV gold ions of 42 keV/nm electronic energy loss are investigated by means of electron microscopy accompanied by electron energy loss spectroscopy showing that there exists a small density reduction in the ion track core. While chemical changes in the ion track are not precluded, evidence of them was not observed. Classical molecular dynamics simulations of thermal spikes in CeO2 with an energy deposition of 12 and 36 keV/nm show damage consisting of isolated point defects at 12 keV/nm, and defect clusters at 36 keV/nm, with no amorphization at either energy. Furthermore, inferences are drawn from modeling about density changes in the ion track and the formation of interstitial loops that shed light on features observed by electron microscopy of swift heavy ion irradiated ceria.

  14. Characterization of swift heavy ion irradiation damage in ceria

    SciTech Connect

    Yablinsky, Clarissa A.; Devanathan, Ram; Pakarinen, Janne; Gan, Jian; Severin, Daniel; Trautmann, Christina; Allen, Todd R.

    2015-03-04

    Swift heavy ion induced radiation damage is investigated for ceria (CeO2), which serves as a UO2 fuel surrogate. Microstructural changes resulting from an irradiation with 940 MeV gold ions of 42 keV/nm electronic energy loss are investigated by means of electron microscopy accompanied by electron energy loss spectroscopy showing that there exists a small density reduction in the ion track core. While chemical changes in the ion track are not precluded, evidence of them was not observed. Classical molecular dynamics simulations of thermal spikes in CeO2 with an energy deposition of 12 and 36 keV/nm show damage consisting of isolated point defects at 12 keV/nm, and defect clusters at 36 keV/nm, with no amorphization at either energy. Inferences are drawn from modeling about density changes in the ion track and the formation of interstitial loops that shed light on features observed by electron microscopy of swift heavy ion irradiated ceria.

  15. Characterization of swift heavy ion irradiation damage in ceria

    DOE PAGESBeta

    Yablinsky, Clarissa A.; Devanathan, Ram; Pakarinen, Janne; Gan, Jian; Severin, Daniel; Trautmann, Christina; Allen, Todd R.

    2015-03-04

    Swift heavy ion induced radiation damage is investigated for ceria (CeO2), which serves as a UO2 fuel surrogate. Microstructural changes resulting from an irradiation with 940 MeV gold ions of 42 keV/nm electronic energy loss are investigated by means of electron microscopy accompanied by electron energy loss spectroscopy showing that there exists a small density reduction in the ion track core. While chemical changes in the ion track are not precluded, evidence of them was not observed. Classical molecular dynamics simulations of thermal spikes in CeO2 with an energy deposition of 12 and 36 keV/nm show damage consisting of isolatedmore » point defects at 12 keV/nm, and defect clusters at 36 keV/nm, with no amorphization at either energy. Furthermore, inferences are drawn from modeling about density changes in the ion track and the formation of interstitial loops that shed light on features observed by electron microscopy of swift heavy ion irradiated ceria.« less

  16. In-situ high temperature irradiation setup for temperature dependent structural studies of materials under swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Kulriya, P. K.; Kumari, Renu; Kumar, Rajesh; Grover, V.; Shukla, R.; Tyagi, A. K.; Avasthi, D. K.

    2015-01-01

    An in-situ high temperature (1000 K) setup is designed and installed in the materials science beam line of superconducting linear accelerator at the Inter-University Accelerator Centre (IUAC) for temperature dependent ion irradiation studies on the materials exposed with swift heavy ion (SHI) irradiation. The Gd2Ti2O7 pyrochlore is irradiated using 120 MeV Au ion at 1000 K using the high temperature irradiation facility and characterized by ex-situ X-ray diffraction (XRD). Another set of Gd2Ti2O7 samples are irradiated with the same ion beam parameter at 300 K and simultaneously characterized using in-situ XRD available in same beam line. The XRD studies along with the Raman spectroscopic investigations reveal that the structural modification induced by the ion irradiation is strongly dependent on the temperature of the sample. The Gd2Ti2O7 is readily amorphized at an ion fluence 6 × 1012 ions/cm2 on irradiation at 300 K, whereas it is transformed to a radiation-resistant anion-deficient fluorite structure on high temperature irradiation, that amorphized at ion fluence higher than 1 × 1013 ions/cm2. The temperature dependent ion irradiation studies showed that the ion fluence required to cause amorphization at 1000 K irradiation is significantly higher than that required at room temperature irradiation. In addition to testing the efficiency of the in-situ high temperature irradiation facility, the present study establishes that the radiation stability of the pyrochlore is enhanced at higher temperatures.

  17. Comparison of Deuterium Retention for Ion-irradiated and Neutron-irradiated Tungsten

    SciTech Connect

    Yasuhisa Oya; Masashi Shimada; Makoto Kobayashi; Takuji Oda; Masanori Hara; Hideo Watanabe; Yuji Hatano; Pattrick Calderoni; Kenji Okuno

    2011-12-01

    The behavior of D retention for Fe{sup 2+}-irradiated tungsten with a damage of 0.025-3 dpa was compared with that for neutron-irradiated tungsten with 0.025 dpa. The D{sub 2} thermal desorption spectroscopy (TDS) spectra for Fe{sup 2+}-irradiated tungsten consisted of two desorption stages at 450 and 550 K, while that for neutron-irradiated tungsten was composed of three stages and an addition desorption stage was found at 750 K. The desorption rate of the major desorption stage at 550K increased as the displacement damage increased due to Fe{sup 2+} irradiation increasing. In addition, the first desorption stage at 450K was found only for damaged samples. Therefore, the second stage would be based on intrinsic defects or vacancy produced by Fe{sup 2+} irradiation, and the first stage should be the accumulation of D in mono-vacancy and the activation energy would be relatively reduced, where the dislocation loop and vacancy is produced. The third one was found only for neutron irradiation, showing the D trapping by a void or vacancy cluster, and the diffusion effect is also contributed to by the high full-width at half-maximum of the TDS spectrum. Therefore, it can be said that the D{sub 2} TDS spectra for Fe{sup 2+}-irradiated tungsten cannot represent that for the neutron-irradiated one, indicating that the deuterium trapping and desorption mechanism for neutron-irradiated tungsten is different from that for the ion-irradiated one.

  18. Late degeneration in rabbit tissues after irradiation by heavy ions

    NASA Technical Reports Server (NTRS)

    Lett, J. T.; Cox, A. B.; Keng, P. C.; Lee, A. C.; Su, C. M.; Bergtold, D. S.

    1980-01-01

    Results are presented for investigations of the late effects of heavy-ion irradiation on rabbit tissues which were undertaken to assess the hazards associated with the long-term exposure of humans to heavy ions in space during such activities as the construction of solar power stations or voyages to Mars. White rabbits approximately six weeks old were exposed to various doses of collimated beams of 400-MeV/n Ne ions, 570 MeV/n Ar ions and Co-60 gamma rays directed through both eyes, and the responses of the various tissues (hair follicles, skin, cornea, lens, retina, Harderian glands, bone and forebrain) were examined. Proliferating tissues are found to exhibit high damage levels in the early and late periods following irradiation, while terminally differentiating tissues repond to radiation most intensely in the late period, years after irradiation, with no intermediate recovery. The results obtained from rabbits are used to predict the occurrence of late tissue degeneration in the central nervous system, terminally differentiating systems and stem cells of humans one or more decades following exposure to radiation levels anticipated during long-duration space flights. The studies also indicate that tissues may be prematurely aged in the sense that tissue life spans may be shortened without the development of malignancies.

  19. Low energy argon ion irradiation surface effects on triglycine sulfate

    NASA Astrophysics Data System (ADS)

    Aragó, Carmen; Plaza, José L.; Marqués, Manuel I.; Gonzalo, Julio A.

    2013-09-01

    An experimental study of the effects of low energy (1-2 keV) argon ion (Ar+) irradiation on Triglycine Sulfate (TGS) has been performed. Ferroelectric parameters, such as the Curie temperature TC determined from the dielectric constant peaks ɛ(T), or the remnant polarization Pr, and coercive field Ec, obtained from the hysteresis loops, show interesting differences between samples irradiated in ferroelectric and paraelectric phases, respectively. The radiation damage seems to be superficial, as observed by AFM microscope, and the surface alteration in both phases becomes eventually notorious when the radiation dosage increases.

  20. Magnetization and susceptibility of ion-irradiated granular magnetite films

    SciTech Connect

    Jiang, W.; McCloy, J. S.; Lea, A. S.; Sundararajan, J. A.; Yao, Q.; Qiang, Y.

    2011-04-01

    Porous granular films of magnetite (Fe{sub 3}O{sub 4}) with grains of {approx}3 nm in size were prepared using a state-of-the-art nanocluster deposition system. The films are initially superparamagnetic but become magnetized following Si{sup 2+} ion irradiation. A significant increase in the grain size and a dramatic change in the microstructure are observed. There are dipolar interactions between the nanoparticles in both the unirradiated and irradiated films. The in-phase alternating current magnetic susceptibility of the unirradiated film shows a blocking temperature of {approx}150 K, depending on frequency. A broadened Verwey transition for the irradiated film occurs at {approx}75 K, above which the susceptibility exhibits unusual behavior: a nearly linear decrease with decreasing temperature. There are irreversible domain rotations in the irradiated film during zero-field cooling and warming cycles between 10 and 300 K. The observed behavior of the irradiated granular films is quite distinct from that of metallic nanostructures after irradiation, and is due to the dramatic change in microstructures.

  1. Metastable hydronium ions in UV-irradiated ice

    SciTech Connect

    Moon, Eui-Seong; Kang, Heon

    2012-11-28

    We show that the irradiation of UV light (10-11 eV) onto an ice film produces metastable hydronium (H{sub 3}O{sup +}) ions in the ice at low temperatures (53-140 K). Evidence of the presence of metastable hydronium ions was obtained by experiments involving adsorption of methylamine onto UV-irradiated ice films and hydrogen-deuterium (H/D) isotopic exchange reaction. The methylamine adsorption experiments showed that photogenerated H{sub 3}O{sup +} species transferred a proton to the methylamine arriving at the ice surface, thus producing the methyl ammonium ion, which was detected by low energy sputtering method. The H{sub 3}O{sup +} species induced the H/D exchange of water, which was monitored through the detection of water isotopomers on the surface by using the Cs{sup +} reactive ion scattering method. Thermal and temporal stabilities of H{sub 3}O{sup +} and its proton migration activity were examined. The lifetime of the hydronium ions in the amorphized ice was greater than 1 h at {approx}53 K and decreased to {approx}5 min at 140 K. Interestingly, a small portion of hydronium ions survived for an extraordinarily long time in the ice, even at 140 K. The average migration distance of protons released from H{sub 3}O{sup +} in the ice was estimated to be about two water molecules at {approx}54 K and about six molecules at 100 K. These results indicate that UV-generated hydronium ions can be efficiently stabilized in low-temperature ice. Such metastable hydronium ions may play a significant role in the acid-base chemistry of ice particles in interstellar clouds.

  2. Temperature measurements during high flux ion beam irradiations.

    PubMed

    Crespillo, M L; Graham, J T; Zhang, Y; Weber, W J

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au(3+) ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 10(12) cm(-2) s(-1). Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect. PMID:26931879

  3. Mutagenic effects of heavy ion irradiation on rice seeds

    NASA Astrophysics Data System (ADS)

    Xu, Xue; Liu, Binmei; Zhang, Lili; Wu, Yuejin

    2012-11-01

    Three varieties of rice seeds were subjected to irradiation using low-energy and medium-energy ions. The damage and mutations induced by the ions were examined. In addition, genetic analysis and gene mapping of spotted leaf (spl) mutants were performed. Low-energy ions had no significant influence on germination, survival or seedling height, except for the survival of Nipponbare. Medium-energy ions had a significant influence on germination and survival but had no significant effect on seedling height. In the low-energy group, among 60,000 M2 plants, 2823 putative morphological mutants were found, and the mutation frequency was approximately 4.71%. In the medium-energy group, 3132 putative morphological mutants were found, and the mutation frequency was approximately 5.22%. Five spl mutants (spl29-spl33) were obtained by ion irradiation, and the heredity of the spl mutants was stable. The characteristics of the spl mutants were found, by genetic analysis and preliminary mapping, to be controlled by a single recessive gene, and spl30 and spl33 were found to be new lesion-mimic mutants.

  4. Temperature measurements during high flux ion beam irradiations

    DOE PAGESBeta

    Crespillo, Miguel L.; Graham, Joseph T.; Zhang, Yanwen; Weber, William J.

    2016-02-16

    A systematic study of the ion beam heating effect was performed in a temperature range of –170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm–2 s–1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggestsmore » that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. Furthermore, a simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beamanalysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.« less

  5. Temperature measurements during high flux ion beam irradiations

    NASA Astrophysics Data System (ADS)

    Crespillo, M. L.; Graham, J. T.; Zhang, Y.; Weber, W. J.

    2016-02-01

    A systematic study of the ion beam heating effect was performed in a temperature range of -170 to 900 °C using a 10 MeV Au3+ ion beam and a Yttria stabilized Zirconia (YSZ) sample at a flux of 5.5 × 1012 cm-2 s-1. Different geometric configurations of beam, sample, thermocouple positioning, and sample holder were compared to understand the heat/charge transport mechanisms responsible for the observed temperature increase. The beam heating exhibited a strong dependence on the background (initial) sample temperature with the largest temperature increases occurring at cryogenic temperatures and decreasing with increasing temperature. Comparison with numerical calculations suggests that the observed heating effect is, in reality, a predominantly electronic effect and the true temperature rise is small. A simple model was developed to explain this electronic effect in terms of an electrostatic potential that forms during ion irradiation. Such an artificial beam heating effect is potentially problematic in thermostated ion irradiation and ion beam analysis apparatus, as the operation of temperature feedback systems can be significantly distorted by this effect.

  6. He ion irradiation damage to Al/Nb multilayers

    SciTech Connect

    Misra, Amit; Li, Nan; Martin, M S; Anderoglu, Osman; Shao, L; Wang, H; Zhang, X

    2009-01-01

    We investigated the evolution of microstructure and mechanical properties of sputter-deposited Al/Nb multilayers with individual layer thickness, h, of 1-200 nm, subjected to helium ion irradiations: 100 keV He{sup +} ions with a dose of 6 x 10{sup 16}/cm{sup 2}. Helium bubbles, 1-2 nm in diameter, were observed. When h is greater than 25 nm, hardnesses of irradiated multilayers barely change, whereas radiation hardening is more significant at smaller h. Transmission electron microscopy and scanning transmission electron microscopy studies reveal the formation of a thin layer of Nb{sub 3}Al intermetallic along the Al/Nb interface as a consequence of radiation induced intermixing. The dependence of radiation hardening on h is interpreted by using a composite model considering the formation of the hard Nb{sub 3}Al intermetallic layer.

  7. Heavy ion tracks in polycarbonate. Comparison with a heavy ion irradiated model compound (diphenyl carbonate)

    NASA Astrophysics Data System (ADS)

    Ferain, E.; Legras, R.

    1993-09-01

    The chemical modifications induced by energetic heavy ion irradiation of polycarbonate (PC) film are determined by GPC, HPLC, ESR, TGA, IR and UV spectrophotometry. The main results of the irradiation are creation of radicals, chain scission, cross-linking and appearance of new chemical groups in the main polymer chain. As far as the creation of new groups is concerned, they are determined by means of a model compound of PC: the diphenyl carbonate (DPC). The following compounds are identified after energetic heavy ion irradiation of DPC: salicylic acid, phenol, 4,4'-biphenol, 2,4'-biphenol, 2,2'-biphenol, 4-phenoxyphenol, 2-phenoxyphenol, phenyl ether, phenyl benzoate, phenyl salicylate, 2-phenylphenol and 2-phenoxyphenyl benzoate. A similarity between the heavy ion irradiation and a heat treatment has also been established with DPC. On the basis of these results, we try to give an explanation of the preferential attack along the tracks of the irradiated film. Also, an explanation of the well-known beneficial effect of an UV exposition of the irradiated film on the selectivity of this preferential chemical attack is suggested.

  8. Track Structure in DNA Irradiated with Heavy Ions

    SciTech Connect

    Bowman, Michael K.; Becker, David; Sevilla, Michael D.; Zimbrick, John D.

    2005-04-01

    The spatial properties of trapped radicals produced in heavy ion-irradiated solid DNA at 77 K have been probed using pulsed Electron Paramagnetic Double Resonance (PELDOR or DEER) techniques. Salmon testes DNA hydrated to twelve water molecules per nucleotide was irradiated with 40Ar ions of energy 100 MeV/nucleon and LET ranging from 300 to 400 keV/?. Irradiated samples were maintained at cryogenic temperature at all times. PELDOR measurements were made using a refocused echo detection sequence that allows dipolar interaction between trapped radicals to be observed. The EPR spectrum is attributed to electron loss/gain DNA base radicals and neutral carbon-centered radicals that likely arise from sugar damage. We find a radical concentration of 13.5*1018 cm-3 in the tracks and a track radius of 6.79 nm. The cross section of these tracks is 144 nm2 yielding a lineal radical density of 2.6 radicals/nm. Based upon the yields previously determined for particles having calculated LET values of 300-400 keV/mm and our measured lineal density, we obtain an LET of 270 keV/mm, which is in good agreement with the calculated range of values. These measurements of radical density and spatial extent provide the first direct experimental determination of track characteristics in irradiated DNA.

  9. Development of an ion beam alignment system for real-time scanning tunneling microscope observation of dopant-ion irradiation

    SciTech Connect

    Kamioka, Takefumi; Sato, Kou; Kazama, Yutaka; Watanabe, Takanobu; Ohdomari, Iwao

    2008-07-15

    An ion beam alignment system has been developed in order to realize real-time scanning tunneling microscope (STM) observation of 'dopant-ion' irradiation that has been difficult due to the low emission intensity of the liquid-metal-ion-source (LMIS) containing dopant atoms. The alignment system is installed in our original ion gun and STM combined system (IG/STM) which is used for in situ STM observation during ion irradiation. By using an absorbed electron image unit and a dummy sample, ion beam alignment operation is drastically simplified and accurized. We demonstrate that sequential STM images during phosphorus-ion irradiation are successfully obtained for sample surfaces of Si(111)-7x7 at room temperature and a high temperature of 500 deg. C. The LMIS-IG/STM equipped with the developed ion beam alignment system would be a powerful tool for microscopic investigation of the dynamic processes of ion irradiation.

  10. Light ion irradiation for unfavorable soft tissue sarcoma

    SciTech Connect

    Linstadt, D.; Castro, J.R.; Phillips, T.L.; Petti, P.L.; Collier, J.M.; Daftari, I.; Schoethaler, R.; Rayner, A.

    1990-09-01

    Between 1978 and 1989, 32 patients with unfavorable soft tissue sarcoma underwent light ion (helium, neon) irradiation with curative intent at Lawrence Berkeley Laboratory. The tumors were located in the trunk in 22 patients and head and neck in 10. Macroscopic tumor was present in 22 at the time of irradiation. Two patients had tumors apparently induced by previous therapeutic irradiation. Follow-up times for surviving patients ranged from 4 to 121 months (median 27 months). The overall 3-year actuarial local control rate was 62%; the corresponding survival rate was 50%. The 3-year actuarial control rate for patients irradiated with macroscopic tumors was 48%, while none of the patients with microscopic disease developed local recurrence (100%). The corresponding 3-year actuarial survival rates were 40% (macroscopic) and 78% (microscopic). Patients with retroperitoneal sarcoma did notably well; the local control rate and survival rate were 64% and 62%, respectively. Complications were acceptable; there were no radiation related deaths, while two patients (6%) required operations to correct significant radiation-related injuries. These results appear promising compared to those achieved by low -LET irradiation, and suggest that this technique merits further investigation.

  11. Effects of ion irradiation on solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Cheng, Jeremy

    The solid oxide fuel cell (SOFC) is an electrochemical device that converts chemical to electrical energy. It is usually based around an oxide conducting ceramic electrolyte that requires temperatures above 800°C to operate. There are many advantages to lowering this operation temperature such as more gas sealing options and more efficient startup. One of the key limitations is in the transport of ions across the electrolyte. The most common electrolyte material used is Yttria-Stabilized Zirconia (YSZ). The ionic conductivity can be greatly affected by grain boundaries, dislocations, and point defects. In this study, dislocations were introduced by heavy ion irradiation. Irradiation with Xe+ or Ar+ produced a large number of point defects and dislocations via a mechanism similar to Frank partial dislocation formation. The dislocation density was on the order of 1012/cm2 and the Burgers vector was 1/2<110>. Heat treatment at temperatures from 800-1400°C changed the defect structure, eliminated point defects, and allowed dislocations to react and grow. Thin films of YSZ were deposited on silicon substrates using pulsed laser deposition (PLD). Films deposited on a metallized substrate were polycrystalline while films deposited directly onto conductive silicon could be epitaxially grown. Ion irradiation caused the film conductivity to drop by a factor of 2-3 due to additional point defects in the film. Heat treatment removed these point defects allowing the conductivity to recover. A novel method was developed to produce freestanding YSZ membranes without a silicon substrate by using the Focused Ion Beam (FIB). Thick, single-crystal YSZ pieces were thinned using in-situ X-Ray Energy Dispersive Spectroscopy (EDS) for end point detection. The final membranes were single crystal, less than 350nm thick, and pinhole free. IV curves and impedance measurements were made after irradiation and heat treatment. The conductivity showed similar trends to the PLD deposited thin

  12. Characterization of polymeric films subjected to lithium ion beam irradiation

    SciTech Connect

    Gary S. Groenewold; W. Roger Cannon; Paul A. Lessing; Recep Avci; Muhammedin Deliorman; Mark Wolfenden; Doug W. Akers; J. Keith Jewell

    2013-02-01

    Two different polymeric materials that are candidate materials for use as binders for mixed uranium–plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H2O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C–O and C–C bonds, which furnish radical intermediates that react by radical recombination with Hradical dot and OHradical dot. Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp2 carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H2O or a H2O–methanol solution, and hence the bulk of the material could not be analyzed using electrospray. However a series of oligomers was leached from the bulk material that produced ion series in the ESI-MS analyses that were identified octylphenyl ethoxylate oligomers. Upon Li ion bombardment, these shifted to a lower average molecular weight, but more importantly showed the emergence of three new ion series that are being formed as a result of radiation damage. Surface analysis of the paraffinic polymers using SIMS produced spectra that were

  13. Characterization of polymeric films subjected to lithium ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Groenewold, Gary S.; Cannon, W. Roger; Lessing, Paul A.; Avci, Recep; Deliorman, Muhammedin; Wolfenden, Mark; Akers, Doug W.; Jewell, J. Keith; Zuck, Larry D.

    2013-02-01

    Two different polymeric materials that are candidate materials for use as binders for mixed uranium-plutonium oxide nuclear fuel pellets were subjected to Li ion beam irradiation, in order to simulate intense alpha irradiation. The materials (a polyethylene glycol 8000 and a microcrystalline wax) were then analyzed using a combination of mass spectrometry (MS) approaches and X-ray photoelectron spectroscopy (XPS). Samples of the irradiated PEG materials were dissolved in H2O and then analyzed using electrospray ionization-MS, which showed the formation of a series of small oligomers in addition to intact large PEG oligomers. The small oligomers were likely formed by radiation-induced homolytic scissions of the C-O and C-C bonds, which furnish radical intermediates that react by radical recombination with Hrad and OHrad . Surface analysis using SIMS revealed a heterogeneous surface that contained not only PEG-derived polymers, but also hydrocarbon-based entities that are likely surface contaminants. XPS of the irradiated PEG samples indicated the emergence of different carbon species, with peak shifts suggesting the presence of sp2 carbon atoms. Analysis of the paraffinic film using XPS showed the emergence of oxygen on the surface of the sample, and also a broadening and shifting of the C1s peak, demonstrating a change in the chemistry on the surface. The paraffinic film did not dissolve in either H2O or a H2O-methanol solution, and hence the bulk of the material could not be analyzed using electrospray. However a series of oligomers was leached from the bulk material that produced ion series in the ESI-MS analyses that were identified octylphenyl ethoxylate oligomers. Upon Li ion bombardment, these shifted to a lower average molecular weight, but more importantly showed the emergence of three new ion series that are being formed as a result of radiation damage. Surface analysis of the paraffinic polymers using SIMS produced spectra that were wholly dominated by

  14. Ion irradiation damage in ilmenite at 100 K

    SciTech Connect

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.; Nord, G.L. Jr.

    1997-10-01

    A natural single crystal of ilmenite (FeTiO{sub 3}) was irradiated at 100 K with 200 keV Ar{sup 2+}. Rutherford backscattering spectroscopy and ion channeling with MeV He{sup +} ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 {times} 10{sup 15} Ar{sup 2+} cm{sup {minus}2}, considerable near-surface He{sup +} ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO{sub 3}) and spinel (MgAl{sub 2}O{sub 4}) to explore factors that may influence radiation damage response in oxides.

  15. Ion irradiation damage in ilmenite under cryogenic conditions

    SciTech Connect

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.; Nord, G.L. Jr.

    1996-11-01

    A natural single crystal of ilmenite was irradiated at 100 K with 200 keV Ar{sup 2+}. Rutherford backscattering spectroscopy and ion channeling with 2 MeV He{sup +} ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 {times} 10{sup 15} Ar{sup 2+} cm{sup {minus}2}, considerable near-surface He{sup +} ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 mm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO{sub 3}) and spinel (MgAl{sub 2}O{sub 4}) to explore factors that may influence radiation damage response in oxides.

  16. Ion irradiation damage in ilmenite at 100 K

    USGS Publications Warehouse

    Mitchell, J.N.; Yu, N.; Devanathan, R.; Sickafus, K.E.; Nastasi, M.A.; Nord, G.L., Jr.

    1997-01-01

    A natural single crystal of ilmenite (FeTiO3) was irradiated at 100 K with 200 keV Ar2+. Rutherford backscattering spectroscopy and ion channeling with 2 MeV He+ ions were used to monitor damage accumulation in the surface region of the implanted crystal. At an irradiation fluence of 1 ?? 1015 Ar2+/cm2, considerable near-surface He+ ion dechanneling was observed, to the extent that ion yield from a portion of the aligned crystal spectrum reached the yield level of a random spectrum. This observation suggests that the near-surface region of the crystal was amorphized by the implantation. Cross-sectional transmission electron microscopy and electron diffraction on this sample confirmed the presence of a 150 nm thick amorphous layer. These results are compared to similar investigations on geikielite (MgTiO3) and spinel (MgAl2O4) to explore factors that may influence radiation damage response in oxides.

  17. The Irradiation Performance and Microstructural Evolution in 9Cr-2W Steel Under Ion Irradiation

    NASA Astrophysics Data System (ADS)

    Alsagabi, Sultan; Charit, Indrajit; Pasebani, Somayeh

    2016-02-01

    Grade 92 steel (9Cr-2W) is a ferritic-martensitic steel with good mechanical and thermal properties. It is being considered for structural applications in Generation IV reactors. Still, the irradiation performance of this alloy needs more investigation as a result of the limited available data. The irradiation performance investigation of Grade 92 steel would contribute to the understanding of engineering aspects including feasibility of application, economy, and maintenance. In this study, Grade 92 steel was irradiated by iron ion beam to 10, 50, and 100 dpa at 30 and 500 °C. In general, the samples exhibited good radiation damage resistance at these testing parameters. The radiation-induced hardening was higher at 30 °C with higher dislocation density; however, the dislocation density was less pronounced at higher temperature. Moreover, the irradiated samples at 30 °C had defect clusters and their density increased at higher doses. On the other hand, dislocation loops were found in the irradiated sample at 50 dpa and 500 °C. Further, the irradiated samples did not show any bubble or void.

  18. Reflection properties of hydrogen ions at helium irradiated tungsten surfaces

    NASA Astrophysics Data System (ADS)

    Doi, K.; Tawada, Y.; Lee, H. T.; Kato, S.; Tanaka, N.; Sasao, M.; Kisaki, M.; Nishiura, M.; Matsumoto, Y.; Kenmotsu, T.; Wada, M.; Ueda, Y.; Yamaoka, H.

    2016-02-01

    Nanostructured W surfaces prepared by He bombardment exhibit characteristic angular distributions of hydrogen ion reflection upon injection of 1 keV H+ beam. A magnetic momentum analyzer that can move in the vacuum chamber has measured the angular dependence of the intensity and the energy of reflected ions. Broader angular distributions were observed for He-irradiated tungsten samples compared with that of the intrinsic polycrystalline W. Both intensity and energy of reflected ions decreased in the following order: the polycrystalline W, the He-bubble containing W, and the fuzz W. Classical trajectory Monte Carlo simulations based on Atomic Collision in Amorphous Target code suggests that lower atom density near the surface can make the reflection coefficients lower due to increasing number of collisions.

  19. Modification of embedded Cu nanoparticles: Ion irradiation at room temperature

    NASA Astrophysics Data System (ADS)

    Johannessen, B.; Kluth, P.; Giulian, R.; Araujo, L. L.; Llewellyn, D. J.; Foran, G. J.; Cookson, D. J.; Ridgway, M. C.

    2007-04-01

    Cu nanoparticles (NPs) with an average diameter of ∼25 Å were synthesized in SiO2 by ion implantation and thermal annealing. Subsequently, the NPs were exposed to ion irradiation at room temperature simultaneously with a bulk Cu reference film. The ion species/energy was varied to achieve different values for the nuclear energy loss. The short-range atomic structure and average NP diameter were measured by means of extended X-ray absorption fine structure spectroscopy and small angle X-ray scattering, respectively. Transmission electron microscopy yielded complementary results. The short-range order of the Cu films remained unchanged consistent with the high regeneration rate of bulk elemental metals. For the NP samples it was found that increasing nuclear energy loss yielded gradual dissolution of NPs. Furthermore, an increased structural disorder was observed for the residual NPs.

  20. Study of ion-irradiated tungsten in deuterium plasma

    NASA Astrophysics Data System (ADS)

    Khripunov, B. I.; Gureev, V. M.; Koidan, V. S.; Kornienko, S. N.; Latushkin, S. T.; Petrov, V. B.; Ryazanov, A. I.; Semenov, E. V.; Stolyarova, V. G.; Danelyan, L. S.; Kulikauskas, V. S.; Zatekin, V. V.; Unezhev, V. N.

    2013-07-01

    Experimental study aimed at investigation of neutron induced damage influence on fusion reactor plasma facing materials is reported. Displacement damage was produced in tungsten by high-energy helium and carbon ions at 3-10 MeV. The reached level of displacement damage ranged from several dpa to 600 dpa. The properties of the irradiated tungsten were studied in steady-state deuterium plasma on the LENTA linear divertor simulator. Plasma exposures were made at 250 eV of ion energy to fluence 1021-1022 ion/сm2. Erosion dynamics of the damaged layer and deuterium retention were observed. Surface microstructure modifications and important damage of the 5 μm layer shown. Deuterium retention in helium-damaged tungsten (ERD) showed its complex behavior (increase or decrease) depending on implanted helium quantity and the structure of the surface layer.

  1. Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces

    SciTech Connect

    Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S.; Sofferman, D. L.; Beskin, I.

    2013-08-12

    We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport.

  2. Observation and mechanism of local oxygen reordering induced by high-energy heavy-ion (U{sup +}, Au{sup +}, Xe{sup +}) irradiation in the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}

    SciTech Connect

    Yan, Y.; Kirk, M.A.

    1998-03-01

    Transmission electron microscopy study reveals that high-energy ({gt}1GeV) heavy-ion (U{sup +}, Au{sup +}, Xe{sup +}) irradiation in the c-axis direction of high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} leads to the formation of aligned columnar defects, which are usually amorphous, and the associated volume expansion causes strain in surrounding matrix. Lobed {open_quotes}bow-tie{close_quotes} contrast is observed in both the [001] zone axis bright field and the high-resolution images of the regions surrounding the amorphous columns, the direction of which is rotated 90{degree} across a typical pre-existing twin boundary in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. Our study shows that this contrast is caused by local oxygen reordering in the ab planes that gives a 90{degree} reorientation of the orthorhombic unit cell in the affected area. The mechanism of resulting oxygen reordering in the ab planes for this area is reported here. A qualitative result on the form, the position, and the size of the oxygen reordering region distributed around an isolated track and between two or more tracks, is related to the orientation of the Cu-O chain direction of matrix and the energy of incident ions. {copyright} {ital 1998} {ital The American Physical Society}

  3. Microstructure of RERTR DU-Alloys Irradiated with Krypton Ions

    SciTech Connect

    J. Gan; D. Keiser; D. Wachs; B. Miller; T. Allen; M. Kirk; J. Rest

    2009-11-01

    Fuel development for reduced enrichment research and test reactor (RERTR) program is tasked with the development of new low enrichment uranium fuels that can be employed to replace existing high enrichment uranium fuels currently used in many research and test reactors worldwide. Radiation stability of the interaction product formed at fuel-matrix interface has a strong impact on fuel performance. Three depleted uranium alloys are cast that consist of the following 5 phases of interest to be investigated: U(Si,Al)3, (U,Mo)(Si,Al)3, UMo2Al20, U6Mo4Al43 and UAl4. Irradiation of TEM disc samples with 500 keV Kr ions at 200?C to high doses up to ~100 dpa were conducted using an intermediate voltage electron microscope equipped with an ion accelerator. The irradiated microstructure of the 5 phases is characterized using transmission electron microscopy. The results will be presented and the implication of the observed irradiated microstructure on the fuel performance will be discussed.

  4. Heavy ion irradiation effects of brannerite-type ceramics

    NASA Astrophysics Data System (ADS)

    Lian, J.; Wang, L. M.; Lumpkin, G. R.; Ewing, R. C.

    2002-05-01

    Brannerite, UTi 2O 6, occurs in polyphase Ti-based, crystalline ceramics that are under development for plutonium immobilization. In order to investigate radiation effects caused by α-decay events of Pu, a 1 MeV Kr + irradiation on UTi 2O 6, ThTi 2O 6, CeTi 2O 6 and a more complex material, composed of Ca-containing brannerite and pyrochlore, was performed over a temperature range of 25-1020 K. The ion irradiation-induced crystalline-to-amorphous transformation was observed in all brannerite samples. The critical amorphization temperatures of the different brannerite compositions are: 970 K, UTi 2O 6; 990 K, ThTi 2O 6; 1020 K, CeTi 2O 6. The systematic increase in radiation resistance from Ce-, Th- to U-brannerite is related to the difference of mean atomic mass of A-site cation in the structure. As compared with the pyrochlore structure-type, brannerite phases are more susceptible to ion irradiation-induced amorphization. The effects of structure and chemical compositions on radiation resistance of brannerite-type and pyrochlore-type ceramics are discussed.

  5. Swift heavy ion irradiation reduces porous silicon thermal conductivity

    NASA Astrophysics Data System (ADS)

    Massoud, M.; Canut, B.; Newby, P.; Frechette, L.; Chapuis, P. O.; Bluet, J. M.

    2014-12-01

    While the electrical conductivity of semiconductors can be easily changed over order of magnitudes (8 in silicon) by playing on the doping, the thermal conductivity (TC) control is a challenging issue. Nevertheless, numerous applications require TC control in Si down to 1 W m-1 K-1. Among them, there are thermal insulation requirements in MEMS, thermal management issues in 3D packaging or TC reduction for thermoelectric applications. Towards this end, the formation of nanoporous Si by electrochemical anodisation is efficient. Nevertheless, in this case the material is too fragile for MEMS application or even to withstand CMOS technological processes. In this work, we show that ion irradiation in the electronic regime is efficient for reducing TC in meso-porous Si (PSi), which is more mechanically robust than the nanoporous PSi. We have studied three different mass to energy ratios (238U at 110 MeV and 130Xe at 91 MeV and 29 MeV) with fluences ranging from 1012 cm-2 to 7 × 1013 cm-2. The sample properties, after irradiation, have been measured by infrared spectroscopy, Raman spectroscopy and scanning electron microscopy. The TC has been measured using scanning thermal microscopy. Although, bulk Si is insensitive to ion interaction in the electronic regime, we have observed the amorphisation of the PSi resulting in a TC reduction even for the low dose and energy. For the highest irradiation dose a very important reduction factor of four was obtained.

  6. Swift heavy ion irradiation of Pt nanocrystals: I. shape transformation and dissolution

    SciTech Connect

    Giulian, R.; Araujo, L.L.; Kluth, P.; Sprouster, D.J.; Schnohr, C.S.; Byrne, A.P.; Ridgway, M.C.

    2014-09-24

    We report on the effects of swift heavy ion irradiation of embedded Pt nanocrystals (NCs), which change from spheres to prolate spheroids to rods upon irradiation. Using a broad range of ion irradiation energies and NC mean sizes we demonstrate that the elongation and dissolution processes are energy and size dependent, attaining comparable levels of shape transformation and dissolution upon a given energy density deposited in the matrix. The NC shape transformation remains operative despite discontinuous ion tracks in the matrix and exhibits a constant threshold size for elongation. In contrast, for ion irradiations in which the ion tracks are continuous, the threshold size for elongation is clearly energy dependent.

  7. Electron cyclotron resonance ion source related development work for heavy-ion irradiation tests

    SciTech Connect

    Koivisto, H.; Suominen, P.; Tarvainen, O.; Virtanen, A.; Parkkinen, A.

    2006-03-15

    The European Space Agency (ESA) uses the facilities at the Accelerator Laboratory (Department of Physics, University of Jyvaeskylae: JYFL) for heavy-ion irradiation tests of electronic components. Electron cyclotron resonance ion source related development work has been carried out in order to meet the requirements set by the project. During the irradiation tests several beam changes are performed during the day. Therefore, the time needed for the beam changes has to be minimized. As a consequence, a beam cocktail having nearly the same m/q ratio is used. This makes it possible a quick tuning of the cyclotron to select the required ion for the irradiation. In addition to this requirement, very high charge states for the heavy elements are needed to reach a penetration depth of 100 {mu}m in silicon. In this article we present some procedures to optimize the ion source operation. We also present results of the first three-frequency heating tests. The main frequency of 14 GHz was fed from a klystron and both secondary frequencies were launched from a traveling-wave tube amplifier (TWTA). Two separate frequency generators were used simultaneously to provide different signals for the TWTA. During the test an improvement of about 20% was observed for {sup 84}Kr{sup 25+} and {sup 129}Xe{sup 30+} ion beams when the third frequency was applied.

  8. Surface ripple evolution by argon ion irradiation in polymers

    NASA Astrophysics Data System (ADS)

    Goyal, Meetika; Aggarwal, Sanjeev; Sharma, Annu

    2016-03-01

    In this report, an attempt has been made to investigate the morphological evolution of nanoscale surface ripples on aliphatic (polypropylene, PP) and aromatic (polyethylene terephthalate, PET) polymeric substrates irradiated with 50 keV Ar+ ions. The specimens were sputtered at off normal incidence of 30° with 5 × 1016 Ar+ cm-2. The topographical features and structural behavior of the specimens were studied using Atomic Force Microscopy (AFM) and UV-Visible spectroscopy techniques, respectively. The Stopping and Range of Ions in Matter simulations were performed to calculate sputtering yield of irradiated PP and PET polymers. Sputtering yield of carbon atoms has been found to be smaller for PP (0.40) as compared to PET (0.73), which is attributed to the different structures of two polymers. AFM analysis demonstrates the evolution of ripple like features with amplitude (2.50 nm) and wavelength (690 nm) on PET while that of lower amplitude (1.50 nm) and higher wavelength (980 nm) on PP specimen. The disorder parameter (Urbach energy) has been found to increase significantly from 0.30 eV to 1.67 eV in case of PP as compared to a lesser increase from 0.35 eV to 0.72 eV in case of PET as revealed by UV-Visible characterization. A mutual correlation between ion beam sputtering induced topographical variations with that of enhancement in the disorder parameter of the specimens has been discussed.

  9. Compaction of microporous amorphous solid water by ion irradiation.

    PubMed

    Raut, U; Teolis, B D; Loeffler, M J; Vidal, R A; Famá, M; Baragiola, R A

    2007-06-28

    We have studied the compaction of vapor-deposited amorphous solid water by energetic ions at 40 K. The porosity was characterized by ultraviolet-visible spectroscopy, infrared spectroscopy, and methane adsorption/desorption. These three techniques provide different and complementary views of the structural changes in ice resulting from irradiation. We find that the decrease in internal surface area of the pores, signaled by infrared absorption by dangling bonds, precedes the decrease in the pore volume during irradiation. Our results imply that impacts from cosmic rays can cause compaction in the icy mantles of the interstellar grains, which can explain the absence of dangling bond features in the infrared spectrum of molecular clouds. PMID:17614568

  10. Development of an Ion Beam Irradiation System for Liquid Crystal Alignment Layer Production

    SciTech Connect

    Matsumoto, Takeshi; Kinoshita, Yuko; Tanii, Masahiro; Tatemichi, Junichi; Konishi, Masashi; Naito, Masao

    2008-11-03

    Ion beam irradiation was employed to produce alignment layers for liquid crystal (LC) displays. The alignment characteristics were compared with those by the conventional rubbing method. Ion incident angle to the films played an important role in LC sample optical qualities. A new ion irradiation method to realize a multi-domain structure for a wide viewing angle was demonstrated.

  11. QUB Low Energy Ion-Ices Irradiation Experiment

    NASA Astrophysics Data System (ADS)

    Muntean, A.; Field, T.; Hunniford, A.; McCullough, B.; Konanoff, J.; Millar, T.

    2011-05-01

    Ion processing plays an important role in the chemical and physical modification of ice surfaces in astrophysical environments. This experimental project supported by the LASSIE ITN, led by Dr Tom Field, will investigate irradiation of astrophysical ice analogues by singly and multiply charged ion analogues of cosmic rays. Singly or multiply charged ions of either gaseous or solid elements are produced by a compact permanent magnet Electron Cyclotron Resonance (ECR) ion source attached to a ''floating beamline'' accelerator. Charge (q) to mass analysed ion beams in the energy range from a few 100 eV to 5xq keV are directed into a dedicated experimental chamber containing a temperature controlled (6K - 300K) cryostatically cooled sample of an astrophysical ice analogue. Current diagnostics include a differentially pumped, high resolution, quadrupole mass spectrometer mounted in ''line of sight'' of the ion impact area of the ice sample In a preliminary collaborative experiment with the groups of Prof Nigel Mason (Open University, UK) and Prof Elisabetta Palumbo (INAF-Osservatorio Astrofisico di Catania. Italy) and using a cryostat and FTIR spectrometer provided by Prof Nigel Mason we studied the interaction of 4 keV C+ and C2+ ions with H2O ices at 30K AND 90K. The most significant species formed in these interactions was 13CO2, the yield of which, with singly charged ions, could be explained by the competition between a formation and a destruction mechanism. In the case of doubly charged ions, explanation of the CO2 yield required additional formation and destruction mechanisms which were considered to be a result of the additional potential energy possessed by the projectile ions. These results also showed the influence of sample temperature and morphology. It is clear that for both singly and doubly charged projectile ions, the yield of 13CO2 was greater at 30K than at 90K. This effect has been observed elsewhere and has been assigned to the greater porosity of

  12. Systematic Ion Irradiation Experiments to Olivine: Comparison with Space Weathered Rims of Itokawa Regolith Particles

    NASA Astrophysics Data System (ADS)

    Matsumoto, T.; Tsuchiyama, A.; Watanabe, N.; Yasuda, K.; Miyake, A.; Nakauchi, Y.; Okada, T.; Abe, M.; Yada, T.; Uesugi, M.; Karouji, Y.; Nakato, A.; Hashiguschi, M.; Kumagai, K.

    2015-11-01

    We performed H and He ion irradiation experiments using olivine fragments, in order to reveal formation time-scales of space weathered rims and formation processes of blisters by solar wind irradiation.

  13. DNA damage in mammalian cells following heavy-ion irradiation

    SciTech Connect

    Rosander, K.; Frankel, K.A.; Cerda, H.; Phillips, M.H.; Lo, E.H.; Fabrikant, I.; Fabrikant, J.I.; Levy, R.P.

    1989-09-01

    In our laboratory we have been investigating DNA damage and repair in the endothelial and oligodendroglial cells of the mouse brain after irradiation using two different types of heavy ions, helium and neon. The method used, the unwinding technique with subsequent staining of the DNA with acridine orange, has been proven to be useful for nondividing cells and analysis using a microscope photometric technique. Our primary goal has been to obtain a measure of RBE, in the dose range used in clinical treatment of various brain disorders using heavy charged particle radiosurgery. 12 refs., 5 figs.

  14. Ion formation in laser-irradiated cesium vapor

    NASA Astrophysics Data System (ADS)

    Mahmoud, M. A.; Gamal, Y. E. E.; Abd El-Rahman, H. A.

    2006-11-01

    We study theoretically the formation of Cs and Cs2+ during cw laser radiation resonant with 6s-7p transition of Cs atomic vapor. This is done by numerically solving rate equations for the evolution of atomic state and electron populations. The results of calculations for the atomic and molecular ions density at different values of laser power clarified that the associative ionization and Penning ionization process play an important role for producing the Cs2+ and Cs, respectively, during the plasma formation. Also, the results showed that laser power of the order of 150 mW and 40 50 ns irradiation time are optimal in producing a fully ionized plasma.

  15. Nanocrystalline zirconia can be amorphized by ion irradiation.

    PubMed

    Meldrum, A; Boatner, L A; Ewing, R C

    2002-01-14

    Nanocrystalline composites are finding applications in high-radiation environments due to their excellent mechanical and electronic properties. We show, however, that at the smallest particle sizes, radiation damage effects can be so strongly enhanced that under the right conditions, materials that have never been made amorphous can become highly susceptible to irradiation-induced amorphization. Because light-weight, high-strength nanocomposites are potential materials for spacecraft shielding and sensor systems, these fundamental results have significant implications for the design and selection of materials to be used in environments where a large ion flux will be encountered. PMID:11801024

  16. SNMS characterization of ion irradiated GaAs surfaces

    NASA Astrophysics Data System (ADS)

    Scandurra, A.; Licciardello, A.; Torrisi, A.; Weigert, R.; Puglisi, O.

    1996-09-01

    This study deals with the phenomena that influence the relative intensity of the sputtered neutral yields when altered layers of GaAs are analysed by using sputtered neutral mass spectrometry (SNMS) technique. The altered layers were obtained by irradiation with He +, Ne +, Ar +, Kr +, Xe + and O 2+ ions of various energies, in order to explore different nuclear stopping power regimes. The main result is a considerable change both of the absolute and relative yields of As and Ga as a function of the bombarding time, type and energy of primary ions. The absolute variation in the sputtered neutral signal is probably related with the amorphization of the outer layers. The relative variation in the yield of As with respect to Ga is not due to true preferential sputtering but to surface segregation followed by removal of the segregated species during the bombardment.

  17. Uniform behavior of insulators irradiated by swift heavy ions

    NASA Astrophysics Data System (ADS)

    Szenes, G.

    2015-07-01

    Ion induced Re track radii are derived from a universal relation Θ(r) without involving any materials parameter apart from the melting point Tm. The effect is related to the formation of identical ion-induced temperature distributions in track forming insulators for =Se / N = constant, where Se, and N are the electronic stopping power and the atomic density. Based on Θ(r), an Re2 - / (Tm -Tir) plot is applied where the experimental curves coincide for various insulators without adjustable parameters (Tir - temperature of irradiation). The analysis extends to all track-forming insulators studied up until now. The application of the equilibrium value of Tm is justified in thermal spike calculations. The physical meaning of the condition =Se / N = constant is discussed. Θ(r) may be valid in those insulators as well in which tracks are not induced. The Fourier equation is not valid under spike conditions.

  18. Neovascular glaucoma after helium ion irradiation for uveal melanoma

    SciTech Connect

    Kim, M.K.; Char, D.H.; Castro, J.L.; Saunders, W.M.; Chen, G.T.; Stone, R.D.

    1986-02-01

    Neovascular glaucoma developed in 22 of 169 uveal melanoma patients treated with helium ion irradiation. Most patients had large melanomas; no eyes containing small melanomas developed anterior segment neovascularization. The mean onset of glaucoma was 14.1 months (range, 7-31 months). The incidence of anterior segment neovascularization increased with radiation dosage; there was an approximately three-fold increase at 80 GyE versus 60 GyE of helium ion radiation (23% vs. 8.5%) (P less than 0.05). Neovascular glaucoma occurred more commonly in larger tumors; the incidence was not affected by tumor location, presence of subretinal fluid, nor rate of tumor regression. Fifty-three percent of patients had some response with intraocular pressures of 21 mmHg or less to a combination of antiglaucoma treatments.

  19. Anderson localization of graphene by helium ion irradiation

    NASA Astrophysics Data System (ADS)

    Naitou, Y.; Ogawa, S.

    2016-04-01

    Irradiation of a single-layer graphene (SLG) with accelerated helium ions (He+) controllably generates defect distributions, which create a charge carrier scattering source within the SLG. We report direct experimental observation of metal-insulator transition in SLG on SiO2/Si substrates induced by Anderson localization. This transition was investigated using scanning capacitance microscopy by monitoring the He+ dose conditions on the SLG. The experimental data show that a defect density of more than ˜1.2% induced Anderson localization. We also investigated the localization length by determining patterned placement of the defects and estimated the length to be several dozen nanometers. These findings provide valuable insight for patterning and designing graphene-based nanostructures using helium ion microscopy.

  20. Formation of long-range ordered quantum dots arrays in amorphous matrix by ion beam irradiation

    SciTech Connect

    Buljan, M.; Bogdanovic-Radovic, I.; Karlusic, M.; Desnica, U. V.; Radic, N.; Dubcek, P.; Drazic, G.; Salamon, K.; Bernstorff, S.; Holy, V.

    2009-08-10

    We demonstrate the production of a well ordered three-dimensional array of Ge quantum dots in amorphous silica matrix. The ordering is achieved by ion beam irradiation and annealing of a multilayer film. Structural analysis shows that quantum dots nucleate along the direction of the ion beam used for irradiation, while the mutual distance of the quantum dots is determined by the diffusion properties of the multilayer material rather than the distances between traces of ions that are used for irradiation.

  1. The change of microstructure and thermal properties in ion irradiated carbon nanotube mats as a function of ion penetration depth

    SciTech Connect

    Aitkaliyeva, A.; Shao, L.

    2013-02-11

    A stack of three carbon nanotube (CNT) mats was irradiated with 3 MeV He ions. The change in structural and thermal properties of individual mats as a function of ion penetration depth was characterized using electron microscopy and laser flash techniques. Ion irradiation can enhance thermal conductivity of the mats by introducing inter-tube displacements, which improve phonon transport across adjacent nanotubes. The enhancement, however, is reduced at higher damage levels due to the increasing phonon-defect scattering within the tubes. This study demonstrates the feasibility of using ion irradiation to manipulate thermal transport in carbon nanotubes.

  2. Application of ion scattering spectroscopy to measurement of surface potential of MgO thin film under ion irradiation

    SciTech Connect

    Nagatomi, T.; Kuwayama, T.; Takai, Y.; Yoshino, K.; Morita, Y.; Kitagawa, M.; Nishitani, M.

    2008-02-25

    An experimental approach was proposed for the measurement of the surface potential (SP) induced on an insulator surface during ion irradiation by ion scattering spectroscopy (ISS). The resultant ISS spectra obtained for a MgO thin film of 600 nm thickness on a Si substrate under 950 eV He{sup +} irradiation revealed that the surface is positively charged by approximately 230 V. In addition, the onset energy of a secondary ion peak indicated a SP of approximately 205 V. The present results confirmed that ISS is an effective technique for measuring the SP during ion irradiation.

  3. Ion irradiation induced disappearance of dislocations in a nickel-based alloy

    NASA Astrophysics Data System (ADS)

    Chen, H. C.; Li, D. H.; Lui, R. D.; Huang, H. F.; Li, J. J.; Lei, G. H.; Huang, Q.; Bao, L. M.; Yan, L.; Zhou, X. T.; Zhu, Z. Y.

    2016-06-01

    Under Xe ion irradiation, the microstructural evolution of a nickel based alloy, Hastelloy N (US N10003), was studied. The intrinsic dislocations are decorated with irradiation induced interstitial loops and/or clusters. Moreover, the intrinsic dislocations density reduces as the irradiation damage increases. The disappearance of the intrinsic dislocations is ascribed to the dislocations climb to the free surface by the absorption of interstitials under the ion irradiation. Moreover, the in situ annealing experiment reveals that the small interstitial loops and/or clusters induced by the ion irradiation are stable below 600 °C.

  4. The discrepancies in multistep damage evolution of yttria-stabilized zirconia irradiated with different ions

    SciTech Connect

    Yang, Tengfei; Taylor, Caitlin A.; Kong, Shuyan; Wang, Chenxu; Zhang, Yanwen; Huang, Xuejun; Xue, Jianming; Yan, Sha; Wang, Yugang

    2013-01-01

    This paper reports a comprehensive investigation of structural damage in yttria-stabilized zirconia irradiated with different ions over a wide fluence range. A similar multistep damage accumulation exists for the irradiations of different ions, but the critical doses for occurrence of second damage step, characterized by a faster increase in damage fraction, and the maximum elastic strain at the first damage step are varied and depend on ion mass. For irradiations of heavier ions, the second damage step occurs at a higher dose with a lower critical elastic strain. Furthermore, larger extended defects were observed in the irradiations of heavy ions at the second damage step. Associated with other experiment results and multistep damage accumulation model, the distinct discrepancies in the damage buildup under irradiations of different ions were interpreted by the effects of electronic excitation, energy of primary knock-on atom and chemistry contributions of deposited ions.

  5. Track formation and dislocation loop interaction in spinel irradiated with swift heavy ions

    NASA Astrophysics Data System (ADS)

    Zinkle, S. J.; Skuratov, V. A.

    1998-05-01

    The microstructure of polycrystalline stoichiometric magnesium aluminate spinel (MgAl 2O 4) has been examined by cross-section electron microscopy following 430 MeV Kr + or 614 MeV Xe + ion irradiation near room temperature up to a fluence of 1.1 × 10 16 ions/m 2. In addition, the microstructure was examined for two spinel specimens which had been preirradiated with either 2 MeV Al + ions or 3.6 MeV Fe + ions and subsequently irradiated with 430 MeV Kr + ions. The Al + and Fe + preirradiated specimens contained a high density (10 21-10 23 m -3) of interstitial dislocation loops with diameters between 5 and 30 nm prior to the swift heavy ion irradiation. Near-continuous latent ion tracks were observed in all of the specimens irradiated with swift heavy ions. The swift heavy ions also appeared to efficiently destroy pre-existing dislocation loops with diameters <5 nm, whereas larger loops remained intact following the swift heavy ion irradiation. The swift heavy ions caused structural disordering of the octahedral cautions, but did not appear to produce amorphous cores in the ion tracks. The disordered ion track diameters were ˜2.0 and ˜2.6 nm for the 430 MeV Kr and 614 MeV Xe ion irradiations, respectively.

  6. Simulation of alpha decay of actinides in iron phosphate glasses by ion irradiation

    NASA Astrophysics Data System (ADS)

    Dube, Charu L.; Stennett, Martin C.; Gandy, Amy S.; Hyatt, Neil C.

    2016-03-01

    A surrogate approach of ion beam irradiation is employed to simulate alpha decay of actinides in iron phosphate nuclear waste glasses. Bismuth and helium ions of different energies have been selected for simulating glass matrix modification owing to radiolysis and ballistic damage due to recoil atoms. Structural modification and change in coordination number of network former were probed by employing Reflectance Fourier-Transform Infrared (FT-IR), and Raman spectroscopies as a consequence of ion irradiation. Depolymerisation is observed in glass sample irradiated at intermediate energy of 2 MeV. Helium blisters of micron size are seen in glass sample irradiated at low helium ion energy of 30 keV.

  7. Amorphisation of boron carbide under slow heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Gosset, D.; Miro, S.; Doriot, S.; Moncoffre, N.

    2016-08-01

    Boron carbide B4C is widely used as a neutron absorber in nuclear plants. Most of the post-irradiation examinations have shown that the structure of the material remains crystalline, in spite of very high atomic displacement rates. Here, we have irradiated B4C samples with 4 MeV Au ions with different fluences at room temperature. Transmission electron microscopy (TEM) and Raman spectroscopy have been performed. The Raman analyses show a high structural disorder at low fluence, around 10-2 displacements per atoms (dpa). However, the TEM observations show that the material remains crystalline up to a few dpa. At high fluence, small amorphous areas a few nanometers large appear in the damaged zone but the long range order is preserved. Moreover, the size and density of the amorphous zones do not significantly grow when the damage increases. On the other hand, full amorphisation is observed in the implanted zone at a Au concentration of about 0.0005. It can be inferred from those results that short range and long range damages arise at highly different fluences, that heavy ions implantation has drastic effects on the structure stability and that in this material self-healing mechanisms are active in the damaged zone.

  8. Detection of DNA damage induced by heavy ion irradiation in the individual cells with comet assay

    NASA Astrophysics Data System (ADS)

    Wada, S.; Natsuhori, M.; Ito, N.; Funayama, T.; Kobayashi, Y.

    2003-05-01

    Investigating the biological effects of high-LET heavy ion irradiation at low fluence is important to evaluate the risk of charged particles. Especially it is important to detect radiation damage induced by the precise number of heavy ions in the individual cells. Thus we studied the relationship between the number of ions traversing the cell and DNA damage produced by the ion irradiation. We applied comet assay to measure the DNA damage in the individual cells. Cells attached on the ion track detector CR-39 were irradiated with ion beams at TIARA, JAERI-Takasaki. After irradiation, the cells were stained with ethidium bromide and the opposite side of the CR-39 was etched. We observed that the heavy ions with higher LET values induced the heavier DNA damage. The result indicated that the amount of DNA damage induced by one particle increased with the LET values of the heavy ions.

  9. Modifications of optical properties of PC/ABS by dual ions beam irradiation

    NASA Astrophysics Data System (ADS)

    Park, Jae-Won; Lee, Jae-Sang; Lee, Byung-hoon; Kim, Min-kyu; Moon, Byung-Sik; Lee, Chan-Young; Choi, Byung-Ho

    2013-03-01

    Polycarbonate (PC)/acrylonitrile butadien styrene (ABS) blends used in the inner parts of automobiles require a glossy and metallic colored optical property. Such a surface can be produced by ion beam irradiation, but the surface treated by a single ion species irradiation tends to be degraded upon a long term exposure under UV and visible lights, which includes the loss of glossiness and the delamination of the irradiated layer. Such degradations can be prevented or greatly reduced by a combined irradiation of heavy and light ions such as N and He ions. This may be attributable to a graded interface between the irradiation affected layer and the base materials by overlapping penetration depths of the heavy and light ions. This work is motivated by an effort to substitute the conventional Cr plating process with the ion beam process in the automobile industry.

  10. Characterisation of dual ion beam irradiated yttria-stabilised zirconia by specific analytical techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Yanwen; Wang, Xu; Liu, Shiyi; Tang, Meixiong; Zhao, Ziqiang

    2015-01-01

    The combined effect of dual ion beam irradiated yttria-stabilized zirconia was investigated through Rutherford backscattering spectrometry/channeling (RBS/C), high resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Compared with other experimental results of single ion beam irradiation, a multistep damage accumulation model can also explain the irradiation effects of dual ion beam. Irradiation damage created by Ar + He ions are simply additive and no synergy effect has been observed. The variation trends of step height and displacement damage are similar. The synergic effects of displacement damage between heavy recoil atoms and α-particle in nuclear waste matrices will not cause more serious damage than the sum of two kinds of ions. The two experimental damage peaks are consistent with those calculated using stopping and range of ions in matter (SRIM). Phase stability and irradiation resistance is further confirmed by high resolution transmission electron microscopy (HRTEM).

  11. Crystal-amorphous-silicon interface kinetics under ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Priolo, F.; La Ferla, A.; Spinella, C.; Rimini, E.; Campisano, S. U.; Ferla, G.

    1990-01-01

    Our recent work on ion-beam-assisted epitaxial growth of amorphous Si layers on single crystal substrates is reviewed. The crystallization was induced by a 600 keV Kr2+ beam at a dose rate of 1×1012/cm2 · s. During irradiations the samples were mounted on a resistively heated copper block whose temperature was maintained constant in the range 250-450°C. The planar motion of the crystal-amorphous interface was monitored in situ by dynamic reflectivity measurements. This technique allows the ion-induced growth rate to be measured with a very high precision. We have observed that this growth rate scales linearly with the energy deposited into elastic collisions at the crystal-amorphous interface by the impinging ions. Moreover, the rate shows an Arrhenius temperature dependence with a well defined activation energy of 0.32±0.05 eV. The dependence of this process on substrate orientation and on impurities either dissolved in the amorphous layer or present at very high concentration at the crystal-amorphous interface is also discussed.

  12. Crystal-amorphous-silicon interface kinetics under ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Priolo, F.; La Ferla, A.; Spinella, C.; Rimini, E.; Campisano, S. U.; Ferla, G.

    1989-11-01

    Our recent work on ion-beam-assisted epitaxial growth of amorphous Si layers on single crystal substrates is reviewed. The crystallization was induced by a 600 keV Kr 2+ beam at a dose rate of 1×10 12/cm 2 · s. During irradiations the samples were mounted on a resistively heated copper block whose temperature was maintained constant in the range 250-450°C. The planar motion of the crystal-amorphous interface was monitored in situ by dynamic reflectivity measurements. This technique allows the ion-induced growth rate to be measured with a very high precision. We have observed that this growth rate scales linearly with the energy deposited into elastic collisions at the crystal-amorphous interface by the impinging ions. Moreover, the rate shows an Arrhenius temperature dependence with a well defined activation energy of 0.32±0.05 eV. The dependence of this process on substrate orientation and on impurities either dissolved in the amorphous layer or present at very high concentration at the crystal-amorphous interface is also discussed.

  13. High temperature ion irradiation effects in MAX phase ceramics

    SciTech Connect

    Clark, D. W.; Zinkle, Steven J.; Patel, Maulik K.; Parish, Chad M.

    2015-12-24

    The family of layered carbides and nitrides known as MAX phase ceramics combine many attractive properties of both ceramics and metals due to their nanolaminate crystal structure and are promising potential candidates for application in future nuclear reactors. This research examines the effects of energetic heavy ion (5.8 MeV Ni) irradiations on polycrystalline samples of Ti3SiC2, Ti3AlC2, and Ti2AlC. The irradiation conditions consisted of midrange ion doses between 10 and 30 displacements per atom at temperatures of 400 and 700⁰C, conditions relevant to application in future nuclear reactors and a relatively un-explored regime for this new class of materials. Following irradiation, a comprehensive analysis of radiation response properties was compiled using grazing incidence X-ray diffraction (XRD), nanoindentation, scanning electron microcopy (SEM), and transmission electron microscopy (TEM). In all cases, XRD and TEM analyses confirm the materials remain fully crystalline although the intense atomic collisions induce significant damage and disorder into the layered crystalline lattice. X-ray diffraction and nanoindentation show this damage is manifest in anisotropic swelling and hardening at all conditions and in all materials, with the aluminum based MAX phase exhibiting significantly more damage than their silicon counterpart. In all three materials there is little damage dependence on dose, suggesting saturation of radiation damage at levels below 10 displacements per atom, and significantly less retained damage at higher temperatures, suggesting radiation defect annealing. SEM surface analysis showed significant grain boundary cracking and loss of damage tolerance properties in the aluminum-based MAX phase irradiated at 400⁰C, but not in the silicon counterpart. TEM analysis of select samples suggest that interstitials are highly mobile while vacancies are immobile and that all three materials are

  14. High temperature ion irradiation effects in MAX phase ceramics

    DOE PAGESBeta

    Clark, D. W.; Zinkle, Steven J.; Patel, Maulik K.; Parish, Chad M.

    2015-12-24

    The family of layered carbides and nitrides known as MAX phase ceramics combine many attractive properties of both ceramics and metals due to their nanolaminate crystal structure and are promising potential candidates for application in future nuclear reactors. This research examines the effects of energetic heavy ion (5.8 MeV Ni) irradiations on polycrystalline samples of Ti3SiC2, Ti3AlC2, and Ti2AlC. The irradiation conditions consisted of midrange ion doses between 10 and 30 displacements per atom at temperatures of 400 and 700⁰C, conditions relevant to application in future nuclear reactors and a relatively un-explored regime for this new class of materials. Followingmore » irradiation, a comprehensive analysis of radiation response properties was compiled using grazing incidence X-ray diffraction (XRD), nanoindentation, scanning electron microcopy (SEM), and transmission electron microscopy (TEM). In all cases, XRD and TEM analyses confirm the materials remain fully crystalline although the intense atomic collisions induce significant damage and disorder into the layered crystalline lattice. X-ray diffraction and nanoindentation show this damage is manifest in anisotropic swelling and hardening at all conditions and in all materials, with the aluminum based MAX phase exhibiting significantly more damage than their silicon counterpart. In all three materials there is little damage dependence on dose, suggesting saturation of radiation damage at levels below 10 displacements per atom, and significantly less retained damage at higher temperatures, suggesting radiation defect annealing. SEM surface analysis showed significant grain boundary cracking and loss of damage tolerance properties in the aluminum-based MAX phase irradiated at 400⁰C, but not in the silicon counterpart. TEM analysis of select samples suggest that interstitials are highly mobile while vacancies are immobile and that all three materials are in the so-called point defect swelling regime

  15. Energetic Ion and Electron Irradiation of the Icy Galilean Satellites

    NASA Technical Reports Server (NTRS)

    Cooper, John F.; Johnson, Robert E.; Mauk, Barry H.; Garrett, Henry B.; Gehrels, Neil

    2001-01-01

    Galileo Orbiter measurements of energetic ions (20 keV to 100 MeV) and electrons (20-700 keV) in Jupiter's magnetosphere are used, in conjunction with the JPL electron model (less than 40 MeV), to compute irradiation effects in the surface layers of Europa, Ganymede, and Callisto. Significant elemental modifications are produced on unshielded surfaces to approximately centimeter depths in times of less than or equal to 10(exp 6) years, whereas micrometer depths on Europa are fully processed in approximately 10 years. Most observations of surface composition are limited to optical depths of approximately 1 mm, which are indirect contact with the space environment. Incident flux modeling includes Stormer deflection by the Ganymede dipole magnetic field, likely variable over that satellite's irradiation history. Delivered energy flux of approximately 8 x 10(exp 10) keV/square cm-s at Europa is comparable to total internal heat flux in the same units from tidal and radiogenic sources, while exceeding that for solar UV energies (greater than 6 eV) relevant to ice chemistry. Particle energy fluxes to Ganymede's equator and Callisto are similar at approximately 2-3 x 10(exp 8) keV/square cm-s with 5 x 10(exp 9) at Ganymede's polar cap, the latter being comparable to radiogenic energy input. Rates of change in optical reflectance and molecular composition on Europa, and on Ganymede's polar cap, are strongly driven by energy from irradiation, even in relatively young regions. Irradiation of nonice materials can produce SO2 and CO2, detected on Callisto and Europa, and simple to complex hydrocarbons. Iogenic neutral atoms and meteoroids deliver negligible energy approximately 10(exp 4-5) keV/square cm-s but impacts of the latter are important for burial or removal of irradiation products. Downward transport of radiation produced oxidants and hydrocarbons could deliver significant chemical energy into the satellite interiors for astrobiological evolution in putative sub

  16. Ion-chain interaction in keV ion-beam-irradiated polystyrene

    SciTech Connect

    Calcagno, L.; Foti, G.; Licciardello, A.; Puglisi, O.

    1987-09-21

    Molecular weight distribution has been measured in monodisperse polystyrene film (MW = 9 000 amu) after ion bombardment, in the ion fluence range 10/sup 11/--10/sup 13/ ions/cm/sup 2/. The chosen beams are 100 keV He, 200 keV Ne, and 400 keV Ar. The experimental data have been interpreted in terms of a simple statistical model for cross-links. The chemical yield is found to be very high and equal to 0.30, about a factor of 10 higher than the values given in the literature for gamma irradiation (M. Dole, in The Radiation Chemistry of Macromolecules (Academic, New York, 1973), Vol. 2, Chap. 5, p. 57).

  17. Defect studies in ion irradiated AlGaN

    SciTech Connect

    Jagielski, Jacek; Thome, Lionel; Zhang, Yanwen; Wang, Chong M.; Turos, Andrzej; Nowicki, L.; Pagowska, K.; Jozwik, I.

    2010-06-01

    Defects created in Al0.4Ga0.6N crystals by 320 keV Ar ion irradiation were studied by using RBS/C and TEM techniques. One of the main aims of the work was to use a new version of McChasy, a Monte – Carlo simulation code of backscattering spectra, for the analysis of experimental results obtained for a dislocations-containing crystal. Transmission Electron Microscopy technique was used to get a better insight into dislocation and dislocation loop geometries in order to restrict the range of parameters used in simulations. RBS/C analysis was performed in a 1.5 MeV – 3 MeV energy range in order to check if MC simulations correctly reproduce backscattering spectra at different energies.

  18. Sympathetic ophthalmia complicating helium ion irradiation of a choroidal melanoma

    SciTech Connect

    Fries, P.D.; Char, D.H.; Crawford, J.B.; Waterhouse, W.

    1987-11-01

    Sympathetic ophthalmia was diagnosed 49 months after helium ion irradiation of a left choroidal melanoma. The patient maintained good vision until 18 months after therapy, when she developed neovascular glaucoma. This complication required multiple therapeutic procedures, including topical anti-inflammatory and antiglaucomatous drops, 360 degrees peripheral panretinal cryoblation, and a single 180 degrees application of inferior cyclocryotherapy over a 2 1/2-year period. Four weeks after the cyclocryotherapy, inflammation was noted in both eyes, and, one month later, enucleation of the left sympathogenic eye was performed. Serial histopathologic sections showed a full-thickness, fibrovascular, scleral scar and tantalum marker ring suture without uveal incarceration. Penetrating surgical trauma, a uveal melanoma, and multiple nonpenetrating treatments resulted in the development of sympathetic ophthalmia.

  19. MeV single-ion beam irradiation of mammalian cells using the Surrey vertical nanobeam, compared with broad proton beam and X-ray irradiations

    NASA Astrophysics Data System (ADS)

    Prakrajang, K.; Jeynes, J. C. G.; Merchant, M. J.; Kirkby, K.; Kirkby, N.; Thopan, P.; Yu, L. D.

    2013-07-01

    As a part of a systematic study on mechanisms involved in physical cancer therapies, this work investigated response of mammalian cells to ultra-low-dose ion beam irradiation. The ion beam irradiation was performed using the recently completed nanobeam facility at the Surrey Ion Beam Centre. A scanning focused vertical ion nano-beam was applied to irradiate Chinese hamster V79 cells. The V79 cells were irradiated in two different beam modes, namely, focused single ion beam and defocused scanning broad ion beam of 3.8-MeV protons. The single ion beam was capable of irradiating a single cell with a precisely controlled number of the ions to extremely low doses. After irradiation and cell incubation, the number of surviving colonies as a function of the number of the irradiating ions was measured for the cell survival fraction curve. A lower survival for the single ion beam irradiation than that of the broad beam case implied the hypersensitivity and bystander effect. The ion-beam-induced cell survival curves were compared with that from 300-kV X-ray irradiation. Theoretical studies indicated that the cell death in single ion irradiation mainly occurred in the cell cycle phases of cell division and intervals between the cell division and the DNA replication. The success in the experiment demonstrated the Surrey vertical nanobeam successfully completed.

  20. Concurrent in situ ion irradiation transmission electron microscope

    SciTech Connect

    Hattar, K.; Bufford, D. C.; Buller, D. L.

    2014-08-29

    An in situ ion irradiation transmission electron microscope has been developed and is operational at Sandia National Laboratories. This facility permits high spatial resolution, real time observation of electron transparent samples under ion irradiation, implantation, mechanical loading, corrosive environments, and combinations thereof. This includes the simultaneous implantation of low-energy gas ions (0.8–30 keV) during high-energy heavy ion irradiation (0.8–48 MeV). In addition, initial results in polycrystalline gold foils are provided to demonstrate the range of capabilities.

  1. Effect of ion irradiation on the properties multi-element plasma coatings

    NASA Astrophysics Data System (ADS)

    Eremin, E. N.; Syzdykova, A. S.; Guchenko, S. A.; Yurov, V. M.; Gyngazova, M. S.

    2016-02-01

    The paper presents the results of the study of ion irradiation on the properties of multi-element plasma coatings. The coatings were bombarded by argon ions using heavy current ion source with a hollow cathode. After ion irradiation, the structure and physical properties of the coatings change, however, the nature of the changes is different for different coatings. To predict the behavior of the coating exposed to irradiation is virtually impossible. Therefore, structural studies and investigation of physical properties of the coatings to determine their functional characteristics are to be conducted.

  2. Secondary particle tracks generated by ion beam irradiation

    NASA Astrophysics Data System (ADS)

    García, Gustavo

    2015-05-01

    The Low Energy Particle Track Simulation (LEPTS) procedure is a powerful complementary tool to include the effect of low energy electrons and positrons in medical applications of radiation. In particular, for ion-beam cancer treatments provides a detailed description of the role of the secondary electrons abundantly generated around the Bragg peak as well as the possibility of using transmuted positron emitters (C11, O15) as a complement for ion-beam dosimetry. In this study we present interaction probability data derived from IAM-SCAR corrective factors for liquid environments. Using these data, single electron and positron tracks in liquid water and pyrimidine have been simulated providing information about energy deposition as well as the number and type of interactions taking place in any selected ``nanovolume'' of the irradiated area. In collaboration with Francisco Blanco, Universidad Complutense de Madrid; Antonio Mu noz, Centro de Investigaciones Energéticas Medioambientales y Tecnológicas and Diogo Almeida, Filipe Ferreira da Silva, Paulo Lim ao-Vieira, Universidade Nova de Lisboa. Supported by the Spanish and Portuguese governments.

  3. Area-selective formation of Si nanocrystals by assisted ion-beam irradiation during dual-ion-beam deposition

    SciTech Connect

    Kim, Jae Kwon; Cha, Kyu Man; Kang, Jung Hyun; Kim, Yong; Yi, Jae-Yel; Chung, Tae Hun; Bark, Hong Jun

    2004-08-30

    We investigate the effect of Ar-ion-beam irradiation during the deposition of SiO{sub x} films by dual-ion-beam deposition system. Ion-beam irradiation effectively increases the oxygen content, x, in SiO{sub x} films indicative of the preferential sputtering of Si phase as compared to SiO{sub 2} phase in SiO{sub x} films. We observe the intense photoluminescence from nonirradiated sample after postdeposition annealing at 1100 deg. C indicating the formation of Si nanocrystals as shown by a cross-sectional transmission electron microscope. However, the increased oxygen content in ion-beam-irradiated sample results in small optical volume of small Si nanocrystals not sufficient for yielding appreciable photoluminescence intensity after postdeposition annealing. The property is utilized for achieving the area-selective formation of Si nanocrytals by inserting a shadow mask in assist ion beam during deposition.

  4. Surface Hardness Improvement of PMMA by Low Energy Ion Irradiation and Electron Irradiation

    NASA Astrophysics Data System (ADS)

    Sakurabayashi, Yuya; Masaki, Takahiro; Iwao, Toru; Yumoto, Motoshige

    Surface modification of PMMA(polymethylmethacrylate) was carried out by irradiation of low energy ion and/or electron, which is expected to improve the surface hardness by introduction of a thin modified layer. Surface hardness was measured by using the nanoindentation test. To clarify the structure and the properties of the modified layer, depth profiles of composition and chemical bonds were analyzed using XPS(X-ray photoelectron spectroscopy). Forming cross-linking structure that contributed to the surface hardness was analyzed using dyeing method. From these results, it was confirmed that surface hardness increased and existence of cross-linking structure. It was suggested that the existence of the structure brought about the increase of surface hardness, and showed the utility of the dyeing method.

  5. Effects of ion irradiation on the residual stresses in Cr thin films

    NASA Astrophysics Data System (ADS)

    Misra, A.; Fayeulle, S.; Kung, H.; Mitchell, T. E.; Nastasi, M.

    1998-08-01

    Cr films sputtered onto {100} Si substrates at room temperature were found to be under residual tension, as revealed by wafer curvature measurements. A 150 nm thick Cr film was bombarded with 300 keV Ar ions after deposition. The intrinsic residual tensile stress increased slightly and then decreased with further increase in the ion dose. For ion doses >1×1015ions/cm2, the stress in the film became compressive and increased with increasing dose. Transmission electron microscopy revealed that the grain boundaries in as-deposited Cr have columnar porosity. A Cr film, ion irradiated to a dose of 5×1015ions/cm2, showed no grain boundary porosity. The changes in the residual stress during ion irradiation are explained by considering Ar incorporation in the film and the manner in which irradiation may change the interatomic distances and forces.

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

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

    2012-09-01

    A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag(+)-Na(+) ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks. PMID:22571943

  8. Deuterium ion irradiation induced precipitation in Fe-Cr alloy: Characterization and effects on irradiation behavior

    NASA Astrophysics Data System (ADS)

    Liu, P. P.; Yu, R.; Zhu, Y. M.; Zhao, M. Z.; Bai, J. W.; Wan, F. R.; Zhan, Q.

    2015-04-01

    A new phase was found to precipitate in a Fe-Cr model alloy after 58 keV deuterium ion irradiation at 773 K. The nanoscale radiation-induced precipitate was studied systematically using high resolution transmission electron microscopy (HRTEM), image simulation and in-situ ultrahigh voltage transmission electron microscopy (HVEM). B2 structure is proposed for the new Cr-rich phase, which adopts a cube-on-cube orientation relationship with regard to the Fe matrix. Geometric phase analysis (GPA) was employed to measure the strain fields around the precipitate and this was used to explain its characteristic 1-dimensional elongation along the <1 0 0> Fe direction. The precipitate was stable under subsequent electron irradiation at different temperatures. We suggest that the precipitate with a high interface-to-volume ratio enhances the radiation resistance of the material. The reason for this is the presence of a large number of interfaces between the precipitate and the matrix, which may greatly reduce the concentration of point defects around the dislocation loops. This leads to a significant decrease in the growth rate.

  9. Influence of high energy ion irradiation on the field emission characteristics of CVD diamond films

    NASA Astrophysics Data System (ADS)

    Koinkar, P. M.; Khairnar, R. S.; Khan, S. A.; Gupta, R. P.; Avasthi, D. K.; More, M. A.

    2006-03-01

    The field emission characteristics of ion-irradiated CVD diamond thin film deposited on silicon substrate has been studied. The diamond thin films, synthesized by hot filament chemical vapor deposition (HFCVD) method, were irradiated by high energy (100 MeV) silver ion (107Ag+ with charge state 9) in the fluence range of 3 × 1011-1 × 1013 ions/cm2. The CVD diamond films were characterized by Raman spectroscopy. The Raman spectra of irradiated samples clearly reveal structural damage due to ion irradiation, which is observed to be fluence dependent. However complete graphitization is not observed. The field emission current-voltage (I-V) characteristics were recorded in 'diode' configuration at base pressure ∼1 × 10-8 mbar. Upon ion irradiation the field emission current is observed to increase with the reduction in the threshold voltage, required to draw 1 μA current. The results indicate that ion irradiation leads to better emission characteristics and the structural damage caused by ion irradiation plays a significant role in emission behavior of CVD diamond films.

  10. Hydride Ions, HCO+ and Ionizing Irradiation in Star Forming Region

    NASA Astrophysics Data System (ADS)

    Benz, Arnold O.; Bruderer, Simon; van Dishoeck, Ewine

    2016-06-01

    Hydrides are fundamental precursor molecules in cosmic chemistry and many hydride ions have become observable in high quality for the first time thanks to the Herschel Space Observatory. Ionized hydrides, such as CH+ and OH+ and also HCO+ affect the chemistry of molecules such as water. They also provide complementary information on irradiation by far UV (FUV) or X-rays and gas temperature.We explore hydrides of the most abundant heavier elements in an observational survey covering star forming regions with different mass and evolutionary state. Twelve YSOs were observed with HIFI on Herschel in 6 spectral settings providing fully velocity-resolved line profiles. The YSOs include objects of low (Class 0 and I), intermediate, and high mass, with luminosities ranging from 4 Ls to 2 105 Ls.The targeted lines of CH+, OH+, H2O+, and C+ are detected mostly in blue-shifted absorption. H3O+ and SH+ are detected in emission and only toward some high-mass objects. For the low-mass YSOs the column density ratios of CH+/OH+ can be reproduced by simple chemical models implying an FUV flux of 2 – 400 times the ISRF at the location of the molecules. In two high-mass objects, the UV flux is 20 – 200 times the ISRF derived from absorption lines, and 300 – 600 ISRF using emission lines. Upper limits for the X-ray luminosity can be derived from H3O+ observations for some low-mass objects.If the FUV flux required for low-mass objects originates at the central protostar, a substantial FUV luminosity, up to 1.5 Ls, is required. For high-mass regions, the FUV flux required to produce the observed molecular ratios is smaller than the unattenuated flux expected from the central object(s) at the Herschel beam radius. This is consistent with an FUV flux reduced by circumstellar extinction or by bloating of the protostar.The ion molecules are proposed to form in FUV irradiated cavity walls that are shocked by the disk wind. The shock region is turbulent, broadening the lines to some 1

  11. First multicharged ion irradiation results from the CUEBIT facility at Clemson University

    SciTech Connect

    Shyam, R.; Kulkarni, D. D.; Field, D. A.; Srinadhu, E. S.; Harriss, J. E.; Cutshall, D. B.; Harrell, W. R.; Sosolik, C. E.

    2015-01-09

    A new electron beam ion trap (EBIT) based ion source and beamline were recently commissioned at Clemson University to produce decelerated beams of multi- to highly-charged ions for surface and materials physics research. This user facility is the first installation of a DREEBIT-designed superconducting trap and ion source (EBIS-SC) in the U.S. and includes custom-designed target preparation and irradiation setups. An overview of the source, beamline, and other facilities as well as results from first measurements on irradiated targets are discussed here. Results include extracted charge state distributions and first data on a series of irradiated metal-oxide-semiconductor (MOS) device targets. For the MOS devices, we show that voltage-dependent capacitance can serve as a record of the electronic component of ion stopping power for an irradiated, encapsulated oxide target.

  12. Structure evolution of mesoporous silica SBA-15 and MCM-41 under swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Lou, Y.; Toquer, G.; Dourdain, S.; Rey, C.; Grygiel, C.; Simeone, D.; Deschanels, X.

    2015-12-01

    Two types of mesoporous silica pellets, SBA-15 and MCM-41, were prepared and irradiated by 20Ne 278 MeV (max. fluence = 2.5 × 1014 ion/cm2) and 36Ar 493 MeV beams (max. fluence = 1 × 1013 ion/cm2). Irradiated and non-irradiated samples were characterized by nitrogen adsorption/desorption analysis, small angle X-ray scattering, and infrared spectrometry. The different behaviours of the two materials under different conditions are observed and discussed. We point out that SBA-15 is more robust than MCM-41 under irradiation.

  13. Damage growth in Si during self-ion irradiation: A study of ion effects over an extended energy range

    SciTech Connect

    Holland, O.W.; El-Ghor, M.K.; White, C.W.

    1989-01-01

    Damage nucleation/growth in single-crystal Si during ion irradiation is discussed. For MeV ions, the rate of growth as well as the damage morphology are shown to vary widely along the track of the ion. This is attributed to a change in the dominant, defect-related reactions as the ion penetrates the crystal. The nature of these reactions were elucidated by studying the interaction of MeV ions with different types of defects. The defects were introduced into the Si crystal prior to high-energy irradiation by self-ion implantation at a medium energy (100 keV). Varied damage morphologies were produced by implanting different ion fluences. Electron microscopy and ion-channeling measurements, in conjunction with annealing studies, were used to characterize the damage. Subtle changes in the predamage morphology are shown to result in markedly different responses to the high-energy irradiation, ranging from complete annealing of the damage to rapid growth. These divergent responses occur over a narrow range of dose (2--3 /times/ 10/sup 14/ cm/sup /minus/2/) of the medium-energy ions; this range also marks a transition in the growth behavior of the damage during the predamage implantation. A model is proposed which accounts for these observations and provides insight into ion-induced growth of amorphous layers in Si and the role of the amorphous/crystalline interface in this process. 15 refs, 9 figs.

  14. Fabrication of a TEM sample of ion-irradiated material using focused ion beam microprocessing and low-energy Ar ion milling.

    PubMed

    Jin, Hyung-Ha; Shin, Chansun; Kwon, Junhyun

    2010-01-01

    Cross-section-view TEM samples of ion-irradiated material are successfully fabricated using a focused ion beam (FIB) system and low-energy Ar ion milling. Ga ion-induced damages in FIB processing are reduced remarkably by the means of low-energy Ar ion milling. There are optimized ion milling conditions for the reduction and removal of the secondary artifacts such as defects and ripples. Incident angles and accelerated voltages are especially more important factors on the preservation of a clean surface far from secondary defects and surface roughing due to Ga and Ar ion bombardment. PMID:20484144

  15. Impact of high dose krypton ion irradiation on corrosion behavior of laser beam welded zircaloy-4

    SciTech Connect

    Wan Qian . E-mail: wanqian99@tsinghua.org.cn; Bai Xinde; Zhang Xiangyu

    2006-02-02

    In order to study the effect of krypton ion irradiation on the aqueous corrosion behavior of laser beam welded zircaloy-4 (LBWZr4), the butt weld joint of zircaloy-4 was made by means of a carbon dioxide laser, subsequently the LBWZr4 samples were irradiated with Kr ions using an accelerator at an energy of 300 keV, with a dose range from 1 x 10{sup 15} to 3 x 10{sup 16} ions/cm{sup 2} at about 150 deg. C. Three-sweep potentiodynamic polarization measurement was employed to evaluate the aqueous corrosion behavior of Kr-irradiated LBWZr4 in a 0.5 M H{sub 2}SO{sub 4} solution. Scanning electron microscopy (SEM) was used to examine the surface topography of the Kr-irradiated LBWZr4 after the potentiodynamic polarization measurement. Transmission electron microscopy was employed to examine the change of microstructures in the irradiated surface. The polarization tests showed that compared with the passive current density of the as-received LBWZr4, the Kr-irradiated LBWZr4 is much lower; however, with the irradiation dose increasing from 1 x 10{sup 15} to 3 x 10{sup 16} ions/cm{sup 2}, the passive current density, closely related to the surface corrosion resistance, increased remarkably. The mechanism of the corrosion behavior transformation was due to the recrystallization of the amorphous phase induced by the lower ion irradiation.

  16. Microstructural evolution in nickel alloy C-276 after Ar-ion irradiation at elevated temperature

    SciTech Connect

    Jin, Shuoxue; He, Xinfu; Li, Tiecheng; Ma, Shuli; Tang, Rui; Guo, Liping

    2012-10-15

    In present work, the irradiation damage in nickel-base alloy C-276 irradiated with Ar-ions was studied. Specimens of C-276 alloy were subjected to an irradiation of Ar-ions (with 120 keV) to dose levels of 6 and 10 dpa at 300 and 550 Degree-Sign C, respectively. The size distributions and densities of dislocation loops caused by irradiation were investigated with transmission electron microscopy. Irradiation hardening due to the formation of the loops was calculated using the dispersed barrier-hardening model, showing that irradiation hardening was greatest at 300 Degree-Sign C/6 dpa. The microstructure evolution induced by Ar-ion irradiation (0-10 dpa) in nickel-base alloy C-276 has been studied using a multi-scale modeling code Radieff constructed based on rate theory, and the size of dislocation loops simulated by Radieff was in good agreement with the experiment. - Highlights: Black-Right-Pointing-Pointer High density of dislocation loops appeared after Ar ions irradiation. Black-Right-Pointing-Pointer Irradiation hardening due to the formation of loops was calculated by the DBH model. Black-Right-Pointing-Pointer Size of loops simulated by Radieff was in good agreement with the experiment.

  17. The effect of electron beam irradiation on silver-sodium ion exchange in silicate glasses

    NASA Astrophysics Data System (ADS)

    Sidorov, Alexander I.; Prosnikov, Mikhail A.

    2016-04-01

    It is shown experimentally that electron irradiation of sodium-silicate glasses makes possible the control of the subsequent ion exchange Ag+ ↔ Na+ process in a salt melt. The reason of this effect is the negatively charged regions formation in a glass volume during electron irradiation. The electric field, produced by these regions in glass volume, results in positive Na+ ions field migration into them. The spatial redistribution of Na+ ions results in the decrease of the ion exchange efficiency, or the ion exchange can be even blocked. This led to the decrease of the luminescence intensity of neutral silver molecular clusters in the irradiated zone, and effect on the silver nanoparticles formation during the subsequent thermal treatment. The observed effects can be used for the control of ion exchange processes during integrated optics devices fabrication, and for the electron-beam recording of optical information.

  18. Comparison of UV and high-energy ion irradiation of methanol:ammonia ice

    NASA Astrophysics Data System (ADS)

    Muñoz Caro, G. M.; Dartois, E.; Boduch, P.; Rothard, H.; Domaracka, A.; Jiménez-Escobar, A.

    2014-06-01

    Aims: The main goal of this work is to compare the effects induced in ices of astrophysical relevance by high-energy ions, simulating cosmic rays, and by vacuum ultraviolet (UV) photons. Methods: This comparison relies on in situ infrared spectroscopy of irradiated CH3OH:NH3 ice. Swift heavy ions were provided by the GANIL accelerator. The source of UV was a microwave-stimulated hydrogen flow discharge lamp. The deposited energy doses were similar for ion beams and UV photons to allow a direct comparison. Results: A variety of organic species was detected during irradiation and later during ice warm-up. These products are common to ion and UV irradiation for doses up to a few tens of eV per molecule. Only the relative abundance of the CO product, after ice irradiation, was clearly higher in the ion irradiation experiments. Conclusions: For some ice mixture compositions, the irradiation products formed depend only weakly on the type of irradiation, swift heavy ions, or UV photons. This simplifies the chemical modeling of energetic ice processing in space.

  19. Spectroscopic study of energetic helium-ion irradiation effects on nuclear graphite tiles

    NASA Astrophysics Data System (ADS)

    Kim, Do Wan; Lee, K. W.; Choi, D. M.; Noh, S. J.; Kim, H. S.; Lee, Cheol Eui

    2016-02-01

    Helium ion-irradiation effects on the nuclear graphite tiles were studied in order to understand the structural modifications and damages that can be produced by fusion reaction in tokamaks. The surface morphological changes due to increasing dose of the irradiation were examined by the field-effect scanning electron microscopy, and X-ray photoelectron spectroscopy elucidated the changes in the shallow surface bonding configurations caused by the energetic irradiation. Raman spectroscopy revealed the structural defects and diamond-like carbon sites that increased with increasing irradiation dose, and the average inter-defect distance was found from the Raman peak intensities as a function of the irradiation dose.

  20. Investigations of structural, dielectric and optical properties on silicon ion irradiated glycine monophosphate single crystals

    NASA Astrophysics Data System (ADS)

    Kanagasekaran, T.; Mythili, P.; Bhagavannarayana, G.; Kanjilal, D.; Gopalakrishnan, R.

    2009-08-01

    The 50 MeV silicon ion irradiation induced modifications on structural, optical and dielectric properties of solution grown glycine monophosphate (GMP) crystals were studied. The high-resolution X-ray diffraction study shows the unaltered value of integrated intensity on irradiation. The dielectric constant as a function of frequency and temperature was studied. UV-visible studies reveal the decrease in bandgap values on irradiation and presence of F-centers. The fluorescence spectrum shows the existence of some energy levels, which remains unaffected after irradiation. The scanning electron micrographs reveal the defects formed on irradiation.

  1. Investigation of the effect of low energy ion beam irradiation on mono-layer graphene

    SciTech Connect

    Xu, Yijun; II. Physikalisches Institut, Universität Göttingen, Friedrich- Hund- Platz 1, 37077 Göttingen; State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 ; Zhang, Kun; Brüsewitz, Christoph; Hofsäss, Hans Christian; Wu, Xuemei; State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050

    2013-07-15

    In this paper, the effect of low energy irradiation on mono-layer graphene was studied. Mono-layer graphene films were irradiated with B, N and F ions at different energy and fluence. X-ray photoelectron spectroscopy indicates that foreign ions implanted at ion energies below 35 eV could dope into the graphene lattice and form new chemical bonds with carbon atoms. The results of Raman measurement indicate that ion beam irradiation causes defects and disorder to the graphene crystal structure, and the level of defects increases with increasing of ion energy and fluence. Surface morphology images also prove that ion beam irradiation creates damages to graphene film. The experiment results suggest that low-energy irradiation with energies of about 30 eV and fluences up to 5·10{sup 14} cm{sup −2} could realize small amount of doping, while introducing weak damage to graphene. Low energy ion beam irradiation, provides a promising approach for controlled doping of graphene.

  2. Grain growth and size distribution in ion-irradiated chemical vapor deposited amorphous silicon

    SciTech Connect

    Spinella, C.; Lombardo, S.; Campisano, S. U.

    1989-07-10

    The amorphous to polycrystal transition in chemical vapor deposited (CVD) amorphous silicon has been studied at 450 /degree/C under Kr ion beam irradiation. The average grain size increases linearly with the ion dose, and the grain size distribution is very narrow compared to thermally grown grains. These results are consistent with the presence of crystal seeds in CVD material. All these seeds can grow simultaneously under ion beam irradiation. For layers completely preamorphized by Ge/sup +/ implantation, no ion beam induced nucleation is observed.

  3. Nano-porosity in GaSb induced by swift heavy ion irradiation

    SciTech Connect

    Kluth, P. Schnohr, C. S.; Giulian, R.; Araujo, L. L.; Lei, W.; Rodriguez, M. D.; Afra, B.; Bierschenk, T.; Ridgway, M. C.; Sullivan, J.; Weed, R.; Li, W.; Ewing, R. C.

    2014-01-13

    Nano-porous structures form in GaSb after ion irradiation with 185 MeV Au ions. The porous layer formation is governed by the dominant electronic energy loss at this energy regime. The porous layer morphology differs significantly from that previously reported for low-energy, ion-irradiated GaSb. Prior to the onset of porosity, positron annihilation lifetime spectroscopy indicates the formation of small vacancy clusters in single ion impacts, while transmission electron microscopy reveals fragmentation of the GaSb into nanocrystallites embedded in an amorphous matrix. Following this fragmentation process, macroscopic porosity forms, presumably within the amorphous phase.

  4. Effect of 100MeV oxygen ion irradiation on silicon NPN power transistor

    SciTech Connect

    Kumar, M. Vinay; Krishnakumar, K. S.; Dinesh, C. M.; Krishnaveni, S.; Ramani

    2012-06-05

    The radiation response of npn Bipolar junction transistor (BJT) has been examined for 100 MeV O{sup 7+} ion. Key electrical properties like Gummel characteristics, dc current gain and capacitance-voltage of 100MeV O{sup 7+} ion irradiated transistor were studied before and after irradiation. The device was decapped and the electrical characterizations were performed at room temperature. Base current is observed to be more sensitive than collector current and gain appears to be degraded with ion fluence, also considerable degradation in C-V characteristics is observed and doping concentration is found to be increased along with the increase in ion fluence.

  5. Effect of Swift Heavy Ion Irradiation on Lithium Zinc Silicate Glasses: A Photoluminescence Study

    SciTech Connect

    Jogad, M. S.; Jogad, R. M.; Sudarsan, V.; Krishna, P. S. R.; Kothiyal, G. P.

    2011-07-15

    Lithium zinc silicate glasses with and without copper were prepared by melt-quench method and their luminescence characteristics after swift heavy ion irradiation has been investigated. Based on these studies it is established that both these glasses contain colour centres and the luminescence from such centres get significantly quenched once these samples get irradiated with 100 MeV swift heavy Ag{sup +} ions with a fluence of 10{sup 13} ions/cm{sup 2} at room temperature. Trapping of the charge carriers by the increased defect concentration brought about by irradiation is responsible for the decrease in the luminescence intensity from the irradiated samples. Copper in these glasses mainly exists as Cu{sup +} ions as revealed by the broad emission around 500 nm.

  6. Investigation of Current Spike Phenomena During Heavy Ion Irradiation of NAND Flash Memories

    NASA Technical Reports Server (NTRS)

    Oldham, Timothy R.; Berg, Melanie; Friendlich, Mark; Wilcox, Ted; Seidleck, Christina; LaBel, Kenneth A.; Irom, Farokh; Buchner, Steven P.; McMorrow, Dale; Mavis, David G.; Eaton, Paul H.; Castillo, James

    2011-01-01

    A series of heavy ion and laser irradiations were performed to investigate previously reported current spikes in flash memories. High current events were observed, however, none matches the previously reported spikes. Plausible mechanisms are discussed.

  7. Irradiation system of ions (H-Xe) for biological studies near the Bragg peak

    NASA Astrophysics Data System (ADS)

    Konishi, Teruaki; Yasuda, Nakahiro; Takeyasu, Akihiro; Ishizawa, Sachi; Fujisaki, Takashi; Matsumoto, Kenichi; Furusawa, Yoshiya; Sato, Yukio; Hieda, Kotaro

    2005-11-01

    We have developed a new system for irradiating biological samples in air with ions from H to Xe below 6.0MeV/nucleon near the Bragg peak. The irradiation system can provide ion beams with 20-mm diameter of which the central area of 100mm2 is uniform in fluence rate within a standard deviation of ±10%. For each ion, the linear energy transfer is selectable by irradiation positions in air, from the lowest at the surface of a vacuum window to the highest at the Bragg peak, for example, from 281 to 977 keV/μm for C ions. A wide range of fluence rates, 10-3-104ions/μm2/s, can be provided by the system, which makes it possible to irradiate a variety of biological samples with different target sizes, from small plasmid DNA to living mammalian cells. The ion fluence irradiated to each sample is calculated from the output of the secondary electron monitor using the linear relationship between the output and ion fluence measured at the sample position by CR-39 track detectors. Survival curves and visualization of NBS1 foci for human cells are presented as examples of preliminary experiments using C ions near the Bragg peak.

  8. Irradiation system of ions (H-Xe) for biological studies near the Bragg peak

    SciTech Connect

    Konishi, Teruaki; Yasuda, Nakahiro; Takeyasu, Akihiro; Ishizawa, Sachi; Fujisaki, Takashi; Matsumoto, Kenichi; Furusawa, Yoshiya; Sato, Yukio; Hieda, Kotaro

    2005-11-15

    We have developed a new system for irradiating biological samples in air with ions from H to Xe below 6.0 MeV/nucleon near the Bragg peak. The irradiation system can provide ion beams with 20-mm diameter of which the central area of 100 mm{sup 2} is uniform in fluence rate within a standard deviation of {+-}10%. For each ion, the linear energy transfer is selectable by irradiation positions in air, from the lowest at the surface of a vacuum window to the highest at the Bragg peak, for example, from 281 to 977 keV/{mu}m for C ions. A wide range of fluence rates, 10{sup -3}-10{sup 4} ions/{mu}m{sup 2}/s, can be provided by the system, which makes it possible to irradiate a variety of biological samples with different target sizes, from small plasmid DNA to living mammalian cells. The ion fluence irradiated to each sample is calculated from the output of the secondary electron monitor using the linear relationship between the output and ion fluence measured at the sample position by CR-39 track detectors. Survival curves and visualization of NBS1 foci for human cells are presented as examples of preliminary experiments using C ions near the Bragg peak.

  9. Structural, Dielectric and Temperature Dependent Raman Spectroscopic Studies on Swift Heavy Ion Irradiated Tgs Crystals

    NASA Astrophysics Data System (ADS)

    Bajpai, P. K.; Shah, Deepak; Kumar, Ravi; Kumar, Ashok; Katiyar, R. S.

    2011-11-01

    Polar cleavage surface of tri-glycine sulphate (TGS) of important room temperature ferroelectric crystal irradiated with 100 MeV oxygen ion beam are characterized to understand the effect of irradiation on structural, dielectric and vibrational modes of the crystal. X-ray diffraction results show lattice parameters a and b in monoclinic unit cell decrease with increasing fluence, whereas parameter `c' increases. However, the irradiated crystal remains in monoclinic phase. Dielectric anomaly peak value associated with paraelectric—ferroelectric phase transition gets reduce with irradiation and Tc shift towards lower temperature. A comparison of the Raman spectra of unirradiated crystal with those irradiated in both paraelectric and ferroelectric phase reveals the molecular ion getting distorted as a result of irradiation.

  10. Study of phase transitions in NbN ultrathin films under composite ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Prikhodko, K.; Gurovich, B.; Dement'eva, M.

    2016-04-01

    This work demonstrates implementation of Selective Displacement of Atoms (SDA) technique to change the crystal structure and atomic composition of thin superconductive film of NbN under low dose composite ion beam irradiation. All structure investigations were performed using High Resolution Transmission Electron Microscopy (HRTEM) technique by the analysis of Fourier transformation of bright field HRTEM images. It was found that composite ion beam irradiation induces the formation of niobium oxynitrides phases.

  11. Application of ion beam irradiated ePTFE to repair small vessel injuries

    NASA Astrophysics Data System (ADS)

    Takahashi, N.; Suzuki, Y.; Ujiie, H.; Hori, T.; Iwaki, M.; Yamada, T.

    2007-04-01

    In surgery, bleeding from small injured vessels often requires prompt hemostasis without occlusion. This study evaluated the usefulness of 0.06 mm thick ion beam irradiated ePTFE sheets to repair small holes in vessels. Both surfaces of ePTFE sheets were irradiated with a 150 keV-Ar+ beam with fluences of 5 × 1014 ions/cm2. A small hole up to 2 mm in diameter was created in the common carotid artery of a rabbit. The defect was wrapped with an ion beam irradiated or non-irradiated ePTFE sheet. Fibrin glue was used to fix the ePTFE sheets to the common carotid artery. Hemostasis was instantly obtained with ion beam irradiated ePTFE but was rather difficult when using a non-irradiated ePTFE sheet. Three weeks after implantation, no occlusion was observed. Histological examination showed that the ePTFE sheets functioned as a scaffold for vessel wall regeneration. Thin ion beam irradiated ePTFE would be useful in vascular surgery.

  12. Oxide shell reduction and magnetic property changes in core-shell Fe nanoclusters under ion irradiation

    SciTech Connect

    Sundararajan, Jennifer A.; Kaur, Maninder; Qiang, You; Jiang, Weilin; McCloy, John S.

    2014-05-07

    Ion irradiation effects are studied on the Fe-based core-shell nanocluster (NC) films with core as Fe and shell as Fe{sub 3}O{sub 4}/Fe{sub 3}N. These NC films were deposited on Si substrates to thickness of ∼0.5 μm using a NC deposition system. The films were irradiated at room temperature with 5.5 MeV Si{sup 2+} ions to ion fluences of 10{sup 15} and 10{sup 16} ions/cm{sup 2}. It is found that the irradiation induces grain growth, Fe valence reduction in the shell, and crystallization or growth of Fe{sub 3}N. The film retained its Fe-core and its ferromagnetic properties after irradiation. The nature and mechanism of oxide shell reduction and composition dependence after irradiation were studied by synthesizing additional NC films of Fe{sub 3}O{sub 4} and FeO + Fe{sub 3}N and irradiating them under the same conditions. The presence of nanocrystalline Fe is found to be a major factor for the oxide shell reduction. The surface morphologies of these films show dramatic changes in the microstructures due to cluster growth and agglomeration as a result of ion irradiation.

  13. Magnetic patterning of Fe/Cr/Fe(001) trilayers by Ga{sup +} ion irradiation

    SciTech Connect

    Blomeier, S.; Hillebrands, B.; Demidov, V.E.; Demokritov, S.O.; Reuscher, B.; Brodyanski, A.; Kopnarski, M.

    2005-11-01

    Magnetic patterning of antiferromagnetically coupled epitaxial Fe (10 nm)/Cr (0.7 nm)/Fe (10 nm) (001) trilayers by irradiation with 30 keV Ga{sup +} ions was studied by means of atomic force microscopy, magnetic force microscopy, and Kerr magnetometry. It was found that within a fluence range of (1.25-5)x10{sup 16} ions/cm{sup 2} a complete transition from antiferromagnetic to ferromagnetic coupling between the two Fe layers can be achieved. The magnetization reversal processes of the nonirradiated, antiferromagnetically coupled areas situated close to the irradiated areas were studied with lateral resolution. Evidence for a lateral coupling mechanism between the magnetic moments of the irradiated and nonirradiated areas was found. Special attention was paid to preserve the flatness of the irradiated samples. Depending on the fluence, topographic steps ranging from +1.5 to -2 nm between the nonirradiated and irradiated areas were observed. At lower fluences the irradiation causes an increase of the surface height, while for higher fluences the height decreases. It was found that for the particular fluence of 2.7x10{sup 16} ions/cm{sup 2} no height difference between the irradiated and nonirradiated areas occurs. The results suggest that the irradiation of Fe/Cr/Fe trilayers with midenergy ions is an innovative method for magnetic patterning, preserving the initial smoothness of the sample.

  14. Magnetoimpedance studies on ion irradiated Co33Fe33Ni7Si7B20 ribbons

    NASA Astrophysics Data System (ADS)

    Kotagiri, Ganesh; Markandeyulu, G.; Thulasiram, K. V.; Fernandes, W. A.; Misra, D.; Tribedi, L. C.

    2016-04-01

    Magnetoimpedance (MI) effect was studied on amorphous Co33Fe33Ni7Si7B20 ribbons that were irradiated with N+1, Ar+2 and Xe+5 ions, at energy of 75 keV. The (MI)m [maximum MI in each case] values are 9.4% and 11%, 9.9% and 6.5%, the largest, for the as-quenched and N+1, Ar+2 and Xe+5 ion irradiated ribbons respectively, at 2 MHz. The (MI)m value of the N+1 ion irradiated ribbon was observed to be the highest, due to an induced in-plane transverse magnetic anisotropy. The saturation magnetizations of the ion-irradiated ribbons are not seen to change with respect to that of the as-quenched ribbon; a small increase in the Ms was observed only upon irradiation with Xe5+ ions. The interaction between the large number of domains, with large uniaxial anisotropy led to large (MI)m values, at frequencies above 8 MHz in the Ar+2 ion irradiated ribbon.

  15. Electrical properties of irradiated PVA film by using ion/electron beam

    NASA Astrophysics Data System (ADS)

    Abdelrahman, M. M.; Osman, M.; Hashhash, A.

    2016-02-01

    Ion/electron beam bombardment has shown great potential for improving the surface properties of polymers. Low-energy charged (ion/electron) beam irradiation of polymers is a good technique to modify properties such as electrical conductivity, structural behavior, and their mechanical properties. This paper reports on the effect of nitrogen and electron beam irradiation on the electrical properties of polyvinyl alcohol (PVA) films. PVA films of 4 mm were exposed to a charged (ion/electron) beam for different treatment times (15, 30, and 60 minutes); the beam was produced from a dual beam source using nitrogen gas with the other ion/electron source parameters optimized. The dielectric loss tangent tan δ , electrical conductivity σ , and dielectric constant ɛ ^' } in the frequency range 100 Hz-100 kHz were measured at room temperature. The variation of dielectric constant and loss tangent as a function of frequency was also studied at room temperature. The dielectric constant was found to be strongly dependent on frequency for both ion and electron beam irradiation doses. The real (ɛ ^' }) and imaginary (ɛ ^' ' }) parts of the dielectric constant decreased with frequency for all irradiated and non-irradiated samples. The AC conductivity showed an increase with frequency for all samples under the influence of both ion and electron irradiation for different times. Photoluminescence (PL) spectral changes were also studied. The formation of clusters and defects (which serve as non-radiative centers on the polymer surface) is confirmed by the decrease in the PL intensity.

  16. Electrical properties of irradiated PVA film by using ion/electron beam

    NASA Astrophysics Data System (ADS)

    Abdelrahman, M. M.; Osman, M.; Hashhash, A.

    2016-02-01

    Ion/electron beam bombardment has shown great potential for improving the surface properties of polymers. Low-energy charged (ion/electron) beam irradiation of polymers is a good technique to modify properties such as electrical conductivity, structural behavior, and their mechanical properties. This paper reports on the effect of nitrogen and electron beam irradiation on the electrical properties of polyvinyl alcohol (PVA) films. PVA films of 4 mm were exposed to a charged (ion/electron) beam for different treatment times (15, 30, and 60 minutes); the beam was produced from a dual beam source using nitrogen gas with the other ion/electron source parameters optimized. The dielectric loss tangent tan δ , electrical conductivity σ , and dielectric constant \\varepsilon ^' } in the frequency range 100 Hz-100 kHz were measured at room temperature. The variation of dielectric constant and loss tangent as a function of frequency was also studied at room temperature. The dielectric constant was found to be strongly dependent on frequency for both ion and electron beam irradiation doses. The real (\\varepsilon ^' }) and imaginary (\\varepsilon ^' ' }) parts of the dielectric constant decreased with frequency for all irradiated and non-irradiated samples. The AC conductivity showed an increase with frequency for all samples under the influence of both ion and electron irradiation for different times. Photoluminescence (PL) spectral changes were also studied. The formation of clusters and defects (which serve as non-radiative centers on the polymer surface) is confirmed by the decrease in the PL intensity.

  17. Low energy Ar+ ion beam irradiation effects on Si ripple pattern.

    PubMed

    Pahlovy, Shahjada A; Yanagimoto, Kazuma; Miyamoto, Iwao

    2011-02-01

    Etching of surfaces by ion beam sputtering is widely used to pattern surfaces. Recent studies using the high-spatial-resolution capability of the scanning tunneling microscope, atomic force microscope and SEM (Scanning Electron Microscopy) disclose in fact that ion bombardment creates repetitive structures at micro-nanometre scale, waves (ripples), checkerboards or pyramids. The phenomenon is related to the interaction between ion erosion and diffusion of adatoms (vacancies), which causes surface re-organization. In this paper we investigated the ripple pattern formation on Si substrates by low energy Ar+ ion bombardment and the dose effect on ripple size. We also briefly discussed the irradiation effects (at normal incidence) on ripple pattern for different irradiation time. Finally, based on Bradley and Harper (BH) theory we proposed a model to understand the mechanism of ripple pattern change due to Ar+ ion beam irradiation. PMID:21456140

  18. Positron annihilation Doppler broadening spectroscopy study on Fe-ion irradiated NHS steel

    NASA Astrophysics Data System (ADS)

    Zhu, Huiping; Wang, Zhiguang; Gao, Xing; Cui, Minghuan; Li, Bingsheng; Sun, Jianrong; Yao, Cunfeng; Wei, Kongfang; Shen, Tielong; Pang, Lilong; Zhu, Yabin; Li, Yuanfei; Wang, Ji; Song, Peng; Zhang, Peng; Cao, Xingzhong

    2015-02-01

    In order to study the evolution of irradiation-induced vacancy-type defects at different irradiation fluences and temperatures, a new type of ferritic/martensitic (F/M) steel named NHS (Novel High Silicon) was irradiated by 3.25 MeV Fe-ion at room temperature and 723 K to fluences of 4.3 × 1015 and 1.7 × 1016 ions/cm2. After irradiation, vacancy-type defects were investigated with variable-energy positron beam Doppler broadening spectra. Energetic Fe-ions produced a large number of vacancy-type defects in the NHS steel, but one single main type of vacancy-type defect was observed in both unirradiated and irradiated samples. The concentration of vacancy-type defects decreased with increasing temperature. With the increase of irradiation fluence, the concentration of vacancy-type defects increased in the sample irradiated at RT, whereas for the sample irradiated at 723 K, it decreased. The enhanced recombination between vacancies and excess interstitial Fe atoms from deeper layers, and high diffusion rate of self-interstitial atoms further improved by diffusion via grain boundary and dislocations at high temperature, are thought to be the main reasons for the reversed trend of vacancy-type defects between the samples irradiated at RT and 723 K.

  19. Conduction mechanisms in ion-irradiated InGaAs layers

    SciTech Connect

    Joulaud, L.; Mangeney, J.; Chimot, N.; Crozat, P.; Fishman, G.; Bourgoin, J.C.

    2005-03-15

    The electrical and optical properties of H{sup +}- and Au{sup +}-irradiated InGaAs layers were studied using Hall-effect, van der Pauw, and relaxation-time measurements. Comparing the different results allows us to obtain information on the nature of the defects created by these two irradiations. Proton irradiation introduces donor-acceptor paired defects. Gold-ion irradiation creates neutral defect clusters and ionized point defects. The carrier mobilities in all of the irradiated materials are degraded, decreasing with increasing irradiation dose. A scattering model taking into account the paired defects is developed and the mobility evolution calculated from this model agrees with the experimental data of both annealed and unannealed samples. The photocurrent spectra reveal a metallic conduction in the band gap in the case of light-ion irradiation, while such type of conduction does not appear for heavy-ion irradiation. This metallic conduction is a consequence of band tailing induced by shallow defects and vanishes when the material is annealed at 400 deg. C. The proton irradiation-induced defects appear to be related to the EL-2-like defects.

  20. Enhancement of band gap and photoconductivity in gamma indium selenide due to swift heavy ion irradiation

    SciTech Connect

    Sreekumar, R.; Jayakrishnan, R.; Sudha Kartha, C.; Vijayakumar, K. P.; Khan, S. A.; Avasthi, D. K.

    2008-01-15

    {gamma}-In{sub 2}Se{sub 3} thin films prepared at different annealing temperatures ranging from 100 to 400 deg. C were irradiated using 90 MeV Si ions with a fluence of 2x10{sup 13} ions/cm{sup 2}. X-ray diffraction analysis proved that there is no considerable variation in structural properties of the films due to the swift heavy ion irradiation. However, photosensitivity and sheet resistance of the samples increased due to irradiation. It was observed that the sample, which had negative photoconductivity, exhibited positive photoconductivity, after irradiation. The negative photoconductivity was due to the combined effect of trapping of photoexcited electrons, at traps 1.42 and 1.26 eV, above the valence band along with destruction of the minority carriers, created during illumination, through recombination. Photoluminescence study revealed that the emission was due to the transition to a recombination center, which was 180 meV above the valence band. Optical absorption study proved that the defects present at 1.42 and 1.26 eV were annealed out by the ion beam irradiation. This allowed photoexcited carriers to reach conduction band, which resulted in positive photoconductivity. Optical absorption study also revealed that the band gap of the material could be increased by ion beam irradiation. The sample prepared at 400 deg. C had a band gap of 2 eV and this increased to 2.8 eV, after irradiation. The increase in optical band gap was attributed to the annihilation of localized defect bands, near the conduction and valence band edges, on irradiation. Thus, by ion beam irradiation, one could enhance photosensitivity as well as the optical band gap of {gamma}-In{sub 2}Se{sub 3}, making the material suitable for applications such as window layer in solar cells.

  1. Enhancement of band gap and photoconductivity in gamma indium selenide due to swift heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Sreekumar, R.; Jayakrishnan, R.; Sudha Kartha, C.; Vijayakumar, K. P.; Khan, S. A.; Avasthi, D. K.

    2008-01-01

    γ-In2Se3 thin films prepared at different annealing temperatures ranging from 100to400°C were irradiated using 90MeV Si ions with a fluence of 2×1013ions/cm2. X-ray diffraction analysis proved that there is no considerable variation in structural properties of the films due to the swift heavy ion irradiation. However, photosensitivity and sheet resistance of the samples increased due to irradiation. It was observed that the sample, which had negative photoconductivity, exhibited positive photoconductivity, after irradiation. The negative photoconductivity was due to the combined effect of trapping of photoexcited electrons, at traps 1.42 and 1.26eV, above the valence band along with destruction of the minority carriers, created during illumination, through recombination. Photoluminescence study revealed that the emission was due to the transition to a recombination center, which was 180meV above the valence band. Optical absorption study proved that the defects present at 1.42 and 1.26eV were annealed out by the ion beam irradiation. This allowed photoexcited carriers to reach conduction band, which resulted in positive photoconductivity. Optical absorption study also revealed that the band gap of the material could be increased by ion beam irradiation. The sample prepared at 400°C had a band gap of 2eV and this increased to 2.8eV, after irradiation. The increase in optical band gap was attributed to the annihilation of localized defect bands, near the conduction and valence band edges, on irradiation. Thus, by ion beam irradiation, one could enhance photosensitivity as well as the optical band gap of γ-In2Se3, making the material suitable for applications such as window layer in solar cells.

  2. Ordered arrangement of irradiation-induced defects of polycrystalline tungsten irradiated with low-energy hydrogen ions

    NASA Astrophysics Data System (ADS)

    Ni, Weiyuan; Yang, Qi; Fan, Hongyu; Liu, Lu; Berthold, Tobias; Benstetter, Günther; Liu, Dongping

    2015-09-01

    Low-energy (20-520 eV) hydrogen ion irradiations were performed at W surface temperature of 373-1073 K and a fluence ranging from 5.0 × 1023 to 1.0 × 1025/m2. Conductive atomic force microscopy (CAFM) as a nondestructive analytical technique was successfully used to detect irradiation-induced defects in polycrystalline W. The size and density of these nanometer-sized defects were strongly dependent on the fluence of hydrogen ions. Both ion energy (E) and temperature (T) play a crucial role in determining the ordering of nanometer-sized defects. Ordered arrangements were formed at relatively high E and T. This can be attributed to the stress-driven ripple effect of defect growth at crystal grains, resulting in the movement of W lattice along one certain crystal planes.

  3. Hydrogen transport through oxide metal surface under atom and ion irradiation

    NASA Astrophysics Data System (ADS)

    Begrambekov, L.; Dvoychenkova, O.; Evsin, A.; Kaplevsky, A.; Sadovskiy, Ya; Schitov, N.; Vergasov, S.; Yurkov, D.

    2014-11-01

    Both the latest and earlier achieved results on gas exchange processes on metal surfaces (including stainless steel, titanium, zirconium, tungsten with deposited aluminum oxide coating) under hydrogen atom or plasma irradiation with occasional oxygen impurity are presented in the paper. Mechanisms and regularities of these processes are discussed. It is demonstrated that surface oxide layer properties as a diffusion barrier strongly depend on external influence on the surface. In particular, it is revealed that low energy hydrogen ion irradiation could slow down hydrogen desorption from metals. Hydrogen atom or ion irradiation combined with simultaneous oxygen admixture accelerates hydrogen desorption from metals.

  4. Silver ion beam irradiation effects on poly(lactide-co-glycolide) (PLGA)/clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Kaur, Manpreet; Singh, Surinder; Mehta, Rajeev

    2014-12-01

    Swift heavy ions induced modification of thin films of blends of poly(lactide-co-glycolide) (PLGA) (50:50) with organically modified nanoclay (Cloisite® 30B) has been studied, using optical, structural and surface morphological analysis. Presence of nanoclay is found to enhance the properties of this degradable copolymer by reducing the rate of degradation even at high irradiation fluence. Optical and structural analysis of the polymer nanocomposites suggests that both the cross-linking and chain scission phenomenon are caused by swift heavy ion irradiation. XRD measurements show intercalation of PLGA in the clay galleries. Surface morphology of a nanocomposite indicates significant changes after irradiation at various fluences.

  5. Magnetic patterning using ion irradiation for highly ordered CoPt alloys with perpendicular anisotropy

    SciTech Connect

    Abes, M.; Venuat, J.; Muller, D.; Carvalho, A.; Schmerber, G.; Beaurepaire, E.; Dinia, A.; Pierron-Bohnes, V.

    2004-12-15

    We used a combination of ion irradiation and e-beam lithography to magnetically pattern an ordered CoPt alloy with strong perpendicular magnetic anisotropy. Ion irradiation disorders the alloy and strongly reduces the magnetic anisotropy. Magnetic force microscopy showed a regular array of 1 {mu}m{sup 2} square dots with perpendicular anisotropy separated by 1 {mu}m large ranges with in-plane anisotropy. This is further confirmed by magnetic measurements, which showed that arrays protected by a 200 nm Pt layer present the same coercive field and the same perpendicular anisotropy as before irradiation. This is promising for applications in magnetic recording technologies.

  6. Precipitate evolution in ion-irradiated HCM12A

    NASA Astrophysics Data System (ADS)

    Jiao, Z.; Was, G. S.

    2012-06-01

    Precipitate evolution in HCM12A following proton irradiations to 3, 7 and 10 dpa at 400 °C, or following Fe++ irradiations to 100 and 500 dpa at 500 °C was studied. Ni/Si/Mn-rich precipitates were irradiation-induced and their nucleation was closely related to the local enrichment of Ni, Si and Mn at sinks such as dislocations due to radiation induced segregation. The composition of Ni/Si/Mn-rich precipitates evolved with irradiation dose and was different from that of the G-phase reported in irradiated ferritic-martensitic alloys. Nucleation of Cu-rich precipitates saturated after 3 dpa at 400 °C and coarsened at higher dose. Irradiation enhanced the precipitation of Cu-rich precipitates at 400 °C but suppressed the nucleation at 500 °C. Partial dissolution of Cu-rich precipitates must have occurred at 500 dpa at 500 °C as the volume fraction was smaller at 500 dpa than that at 100 dpa. Cr-rich precipitates were irradiation enhanced and were observed under irradiation at 400 °C but not observed at 500 °C due to the increase in Cr solubility with temperature. The evolution of Cr-rich precipitates with irradiation dose was likely related to the complex redistribution of Cr among chromium carbides, grain boundaries and matrix under irradiation. Radiation-induced Cr-rich carbides were observed following Fe++ irradiation to 500 dpa at 500 °C.

  7. Irradiation influence on Mylar and Makrofol induced by argon ions in a plasma immersion ion implantation system

    NASA Astrophysics Data System (ADS)

    Hassan, A.; El-Saftawy, A. A.; Aal, S. A. Abd El; Ghazaly, M. El

    2015-08-01

    Mylar and Makrofol polycarbonate polymers were irradiated by Ar ions in a plasma immersion ion implantation (PIII) system. The surface wettability of both polymers was investigated by employing the contact angle method. The measured contact angles were found to depend on the surface layer properties. Good wetting surfaces were found to depend not only on surface roughness but also on its chemistry that analyzed by Fourier transform infrared (FTIR) spectroscopy. Surfaces topography and roughness was investigated and correlated to their surface energy which studied with the aid of acid-base model for evaluating the improvement of surface wettability after irradiation. PIII improves polymers surface properties efficiently in a controllable way.

  8. Studies on PAN-based carbon fibers irradiated by Ar+ ion beams.

    PubMed

    Park, Soo-Jin; Seo, Min-Kang; Kim, Hak-Yong; Lee, Douk-Rae

    2003-05-15

    In this work, the effects of Ar+ ion beam irradiation on carbon fibers were studied using tensile and surface analytical techniques. The single-fiber pull-out test was executed in order to characterize the fiber/epoxy matrix interfacial adhesion. The Ar+ ion beam was irradiated using an ion-assisted reaction (IAR) method in reactive gas conditions under an oxygen environment with 1 x 10(16) ions/cm(2) Ar+ ion dose (ID), 6 sccm blown gas flow rate, and different ion beam energy intensities. From the experimental results, both the interfacial shear strength (IFSS) and fracture toughness (Gi) were found to increase with increasing Ar+ ion irradiation intensity. This was probably due to the fact that Ar+ ion beam irradiation on carbon fibers was effective in altering their surface physical chemistry and structural morphology, resulting in improved interfacial adhesion in the fiber/epoxy matrix. The reliability of single-fiber pull-out test data could be improved by statistical analysis using the Weibull distribution, which served to predict the variation of the mechanical interfacial properties in a composite system. PMID:16256547

  9. Oxide Shell Reduction and Magnetic Property Changes in Core-Shell Fe Nanoclusters under Ion Irradiation

    SciTech Connect

    Sundararajan, Jennifer A.; Kaur, Maninder; Jiang, Weilin; McCloy, John S.; Qiang, You

    2014-02-12

    Ion irradiation effects are studied on the Fe-based core-shell nanocluster (NC) films with core as Fe and shell as Fe3O4/FeO. These NC films were were deposited on Si substrates to thickness of ~0.5 micrometers using a NC deposition system. The films were irradiated at room temperature with 5.5 MeV Si2+ ions to ion fluences of 1015 and 1016 ions/cm2. It is found that the irradiation induces grain growth, Fe valence reduction in the shell, and crystallization of Fe3N. The nature and mechanism of oxide shell reduction and composition dependence after irradiation were studied by synthesizing additional NC films of Fe3O4 and FeO+Fe3N and irradiating them under the same conditions. The presence of nanocrystalline Fe is found to be a major factor for the oxide shell reduction. The surface morphologies of these films show dramatic changes in the microstructures due to cluster growth and agglomeration as a result of ion irradiation.

  10. Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

    SciTech Connect

    Zinkle, S.J.; Snead, L.L.

    1995-12-31

    Polycrystalline Al2O3, magnesium aluminate spinel (MgAl2O4), MgO, Si3N4, and SiC were irradiated with various ions at 200-450 K, and microstructures were examined following irradiation using cross-section TEM. Amorphization was not observed in any of the irradiated oxide ceramics, despsite damage energy densities up to {similar_to}7 keV/atom (70 displacements per atom). On the other hand, SiC readily amorphized after damage levels of {similar_to}0.4 dpa at room temperature (RT). Si3N4 exhibited intermediate behavior; irradiation with Fe{sup 2+} ions at RT produced amorphization in the implanted ion region after damage levels of {similar_to}1 dpa. However, irradiated regions outside the implanted ion region did not amorphize even after damage levels > 5 dpa. The amorphous layer in the Fe-implanted region of Si3N4 did not appear if the specimen was simultaneoulsy irradiated with 1-MeV He{sup +} ions at RT. By comparison with published results, it is concluded that the implantation of certain chemical species has a pronounced effect on the amorphization threshold dose of all five materials. Intense ionizing radiation inhibits amorphization in Si3N4, but does not appear to significantly influence the amorphization of SiC.

  11. Ion irradiation induced defect evolution in Ni and Ni-based FCC equiatomic binary alloys

    DOE PAGESBeta

    Jin, Ke; Zhang, Yanwen; Bei, Hongbin

    2016-01-01

    In order to explore the chemical effects on radiation response of alloys with multi-principal elements, defect evolution under Au ion irradiation was investigated in the elemental Ni, equiatomic NiCo and NiFe alloys. Single crystals were successfully grown in an optical floating zone furnace and their (100) surfaces were irradiated with 3 MeV Au ions at fluences ranging from 1 × 1013 to 5 × 1015 ions cm–2 at room temperature. The irradiation-induced defect evolution was analyzed by using ion channeling technique. Experiment shows that NiFe is more irradiation-resistant than NiCo and pure Ni at low fluences. With continuously increasing themore » ion fluences, damage level is eventually saturated for all materials but at different dose levels. The saturation level in pure Ni appears at relatively lower irradiation fluence than the alloys, suggesting that damage accumulation slows down in the alloys. Here, under high-fluence irradiations, pure Ni has wider damage ranges than the alloys, indicating that defects in pure Ni have high mobility.« less

  12. Ion irradiation induced defect evolution in Ni and Ni-based FCC equiatomic binary alloys

    SciTech Connect

    Jin, Ke; Zhang, Yanwen; Bei, Hongbin

    2016-01-01

    In order to explore the chemical effects on radiation response of alloys with multi-principal elements, defect evolution under Au ion irradiation was investigated in the elemental Ni, equiatomic NiCo and NiFe alloys. Single crystals were successfully grown in an optical floating zone furnace and their (100) surfaces were irradiated with 3 MeV Au ions at fluences ranging from 1 × 1013 to 5 × 1015 ions cm–2 at room temperature. The irradiation-induced defect evolution was analyzed by using ion channeling technique. Experiment shows that NiFe is more irradiation-resistant than NiCo and pure Ni at low fluences. With continuously increasing the ion fluences, damage level is eventually saturated for all materials but at different dose levels. The saturation level in pure Ni appears at relatively lower irradiation fluence than the alloys, suggesting that damage accumulation slows down in the alloys. Here, under high-fluence irradiations, pure Ni has wider damage ranges than the alloys, indicating that defects in pure Ni have high mobility.

  13. Ion irradiation induced defect evolution in Ni and Ni-based FCC equiatomic binary alloys

    NASA Astrophysics Data System (ADS)

    Jin, K.; Bei, H.; Zhang, Y.

    2016-04-01

    In order to explore the chemical effects on radiation response of alloys with multi-principal elements, defect evolution under Au ion irradiation was investigated in the elemental Ni, equiatomic NiCo and NiFe alloys. Single crystals were successfully grown in an optical floating zone furnace and their (100) surfaces were irradiated with 3 MeV Au ions at fluences ranging from 1 × 1013 to 5 × 1015 ions cm-2 at room temperature. The irradiation-induced defect evolution was analyzed by using ion channeling technique. Experiment shows that NiFe is more irradiation-resistant than NiCo and pure Ni at low fluences. With continuously increasing the ion fluences, damage level is eventually saturated for all materials but at different dose levels. The saturation level in pure Ni appears at relatively lower irradiation fluence than the alloys, suggesting that damage accumulation slows down in the alloys. Under high-fluence irradiations, pure Ni has wider damage ranges than the alloys, indicating that defects in pure Ni have high mobility.

  14. Amorphization resistance of nano-engineered SiC under heavy ion irradiation

    DOE PAGESBeta

    Imada, Kenta; Ishimaru, Manabu; Xue, Haizhou; Zhang, Yanwen; Shannon, Steven C.; Weber, William J.

    2016-06-19

    Silicon carbide (SiC) with a high-density of planar defects (hereafter, ‘nano-engineered SiC’) and epitaxially-grown single-crystalline 3C-SiC were simultaneously irradiated with Au ions at room temperature, in order to compare their relative resistance to radiation-induced amorphization. Furthermore, it was found that the local threshold dose for amorphization is comparable for both samples under 2 MeV Au ion irradiation; whereas, nano-engineered SiC exhibits slightly greater radiation tolerance than single crystalline SiC under 10 MeV Au irradiation. Under 10 MeV Au ion irradiation, the dose for amorphization increased by about a factor of two in both nano-engineered and single crystal SiC due tomore » the local increase in electronic energy loss that enhanced dynamic recovery.« less

  15. Amorphization resistance of nano-engineered SiC under heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Imada, Kenta; Ishimaru, Manabu; Xue, Haizhou; Zhang, Yanwen; Shannon, Steven C.; Weber, William J.

    2016-09-01

    Silicon carbide (SiC) with a high-density of planar defects (hereafter, 'nano-engineered SiC') and epitaxially-grown single-crystalline 3C-SiC were simultaneously irradiated with Au ions at room temperature, in order to compare their relative resistance to radiation-induced amorphization. It was found that the local threshold dose for amorphization is comparable for both samples under 2 MeV Au ion irradiation; whereas, nano-engineered SiC exhibits slightly greater radiation tolerance than single crystalline SiC under 10 MeV Au irradiation. Under 10 MeV Au ion irradiation, the dose for amorphization increased by about a factor of two in both nano-engineered and single crystal SiC due to the local increase in electronic energy loss that enhanced dynamic recovery.

  16. Resistivity and phonon softening in ion-irradiated epitaxial gold films

    SciTech Connect

    Kaestle, G.; Mueller, T.; Boyen, H.-G.; Klimmer, A.; Ziemann, P.

    2004-12-15

    The influence of ion irradiation-induced defects on the temperature dependence of the resistivity of epitaxial, thin (25 nm), and ultrathin (7 nm) gold films was investigated. To include surface scattering properly, the analysis was performed with the classical size-effect model of Fuchs-Sondheimer. Values for the residual resistivity, the specularity parameter p, and the Debye temperature were obtained. It turned out that ion irradiation not only leads to an expected increase of the resistivity but also to a modification of electron-phonon scattering. With increasing defect density, the effective Debye temperature was significantly reduced. This reduction was less pronounced for He{sup +} as compared to Ar{sup +} irradiation pointing towards vacancy clustering in the latter case. In ultrathin films (7 nm), the Debye temperature is reduced already in the as-prepared state due to an increased surface-to-volume ratio, and ion irradiation-induced defects do not lead to a further reduction.

  17. Tailoring nonlinear optical properties of Bi2Se3 through ion irradiation.

    PubMed

    Tan, Yang; Guo, Zhinan; Shang, Zhen; Liu, Fang; Böttger, Roman; Zhou, Shengqiang; Shao, Jundong; Yu, Xuefeng; Zhang, Han; Chen, Feng

    2016-01-01

    The nonlinear optical property of topological insulator bismuth selenide (Bi2Se3) is found to be well-tailored through ion irradiation by intentionally introducing defects. The increase of the optical modulation depth sensitively depends on the careful selection of the irradiation condition. By implementing the ion irradiated Bi2Se3 film as an optical saturable absorber device for the Q-switched wave-guide laser, an enhanced laser performance has been obtained including narrower pulse duration and higher peak power. Our work provides a new approach of tailoring the nonlinear optical properties of materials through ion irradiation, a well-developed chip-technology, which could find wider applicability to other layered two-dimensional materials beyond topological insulators, such as graphene, MoS2, black phosphours etc. PMID:26888223

  18. Tailoring nonlinear optical properties of Bi2Se3 through ion irradiation

    PubMed Central

    Tan, Yang; Guo, Zhinan; Shang, Zhen; Liu, Fang; Böttger, Roman; Zhou, Shengqiang; Shao, Jundong; Yu, Xuefeng; Zhang, Han; Chen, Feng

    2016-01-01

    The nonlinear optical property of topological insulator bismuth selenide (Bi2Se3) is found to be well-tailored through ion irradiation by intentionally introducing defects. The increase of the optical modulation depth sensitively depends on the careful selection of the irradiation condition. By implementing the ion irradiated Bi2Se3 film as an optical saturable absorber device for the Q-switched wave-guide laser, an enhanced laser performance has been obtained including narrower pulse duration and higher peak power. Our work provides a new approach of tailoring the nonlinear optical properties of materials through ion irradiation, a well-developed chip-technology, which could find wider applicability to other layered two-dimensional materials beyond topological insulators, such as graphene, MoS2, black phosphours etc. PMID:26888223

  19. Tailoring nonlinear optical properties of Bi2Se3 through ion irradiation

    NASA Astrophysics Data System (ADS)

    Tan, Yang; Guo, Zhinan; Shang, Zhen; Liu, Fang; Böttger, Roman; Zhou, Shengqiang; Shao, Jundong; Yu, Xuefeng; Zhang, Han; Chen, Feng

    2016-02-01

    The nonlinear optical property of topological insulator bismuth selenide (Bi2Se3) is found to be well-tailored through ion irradiation by intentionally introducing defects. The increase of the optical modulation depth sensitively depends on the careful selection of the irradiation condition. By implementing the ion irradiated Bi2Se3 film as an optical saturable absorber device for the Q-switched wave-guide laser, an enhanced laser performance has been obtained including narrower pulse duration and higher peak power. Our work provides a new approach of tailoring the nonlinear optical properties of materials through ion irradiation, a well-developed chip-technology, which could find wider applicability to other layered two-dimensional materials beyond topological insulators, such as graphene, MoS2, black phosphours etc.

  20. Grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation

    SciTech Connect

    Zhang Yanwen; Jiang Weilin; Wang Chongmin; Edmondson, Philip D.; Zhu Zihua; Gao Fei; Namavar, Fereydoon; Lian Jie; Weber, William J.

    2010-11-01

    Grain growth, oxygen stoichiometry, and phase stability of nanostructurally stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au-ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with irradiation dose to {approx}30 nm at {approx}35 dpa. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from {approx}2.0 for the as-deposited films to {approx}1.65 after irradiation to {approx}35 dpa. The loss of oxygen suggests a significant increase in oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.

  1. Optical and structural properties of 100 MeV Fe9+ ion irradiated InP

    NASA Astrophysics Data System (ADS)

    Dubey, R. L.; Dubey, S. K.; Bodhane, S. P.; Kanjilal, D.

    2016-05-01

    Single crystal InP samples were irradiated with 100 MeV Fe9+ ions for ion fluences 1x1012 and 1x1013 cm-2. Optical properties of irradiated InP was investigated by Spectroscopic Ellipsometry and UV-VIS-NIR spectroscopy. The optical parameters like, refractive index, extinction coefficient, absorption coefficient is found to be fluence dependent near the surface as well as near the projected range. Small change in the optical parameters near the surface region as investigated by Spectroscopic Ellipsometry indicatesthat the surfaces of irradiated InP are similar to non-irradiated InP. This is also supported by RBS/C measurements. The UV-VIS-NIR study revealed the decrease in the band gap and increase in the defect concentration in the irradiated sample as a result of nuclear energy loss.

  2. Enhancement of impact-induced mechanoluminescence by swift heavy ion irradiation

    SciTech Connect

    Zhan, T. Z.; Terasawa, Y.; Xu, C. N.; Yamada, H.; Zhang, L.; Iwase, H.; Kawai, M.

    2012-01-02

    In this Letter, we report a strategy using swift heavy ion (SHI) irradiation to enhance the impact-induced mechanoluminescence (ML) in ML materials. The impact-induced ML intensity of CaSrAl{sub 2}Si{sub 2}O{sub 8}:Eu{sup 2+} was enhanced by about one order of magnitude by using SHI irradiation. Furthermore, the enhancement was found to depend on electronic stopping power and irradiation fluence. The density of traps of a type suitable for impact-induced ML is considered to be increased by the SHI irradiation, resulting in the impact-induced ML enhancement.

  3. Selected degradation reactions in polyethylene irradiated with Ar + and Xe + ions

    NASA Astrophysics Data System (ADS)

    Pros̆ková, K.; S̆vorc̆ík, V.; Rybka, V.; Hnatowicz, V.

    2000-04-01

    Polyethylene (PE) was irradiated with 63 keV Ar + and 156 keV Xe + ions ( RP=100 nm for both ions) to the fluences from 1×10 13 to 3×10 15 cm -2. Degradation processes in the PE surface layer, modified by the ion irradiation, were characterized by measuring depth profiles of residual hydrogen and incorporated oxygen (RBS/ERD techniques), free radical concentration (EPR) and conjugated double bond concentration (UV-VIS). Dehydrogenation due to release of a part of volatile degradation products was observed. Interactions among free radicals, produced along the ion path, result in a creation of new, conjugated double bonds. Some of free radicals react with oxygen coming from ambient atmosphere in the ion implanter and in this way, oxidized structures are produced. Dehydrogenation of PE chains and degradation of oxidized structures, appear to be related to the energy locally deposited via ion electronic energy loss.

  4. Fabrication of Pt nanoparticle incorporated polymer nanowires by high energy ion and electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Tsukuda, Satoshi; Takahasi, Ryouta; Seki, Shu; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shun-Ichiro

    2016-01-01

    Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including H2PtCl6. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and H2PtCl6. However, increasing the amount of H2PtCl6 led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.

  5. Ion-irradiation enhanced epitaxial growth of sol-gel TiO2 films

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Kun; Jung, Hyun Suk; Wang, Yongqiang; Theodore, N. David; Alford, Terry L.; Nastasi, Michael

    2011-04-01

    We report the epitaxial growth of sol-gel TiO2 films by using ion-irradiation enhanced synthesis. Our present study shows that the ion-beam process can provide highly crystalline TiO2 even at 350°C. Nuclear energy deposition at amorphous/crystalline interface plays a dominant role in the epitaxial growth of the films at the reduced temperature via a defect-migration mechanism. In addition, the ion irradiation allows for increasing the film density by balancing the crystallization rate and the escape rate of organic components.

  6. Improvement in both giant magnetoresistance and exchange bias through hydrogen ion irradiation at low energy

    SciTech Connect

    Shim, Jaechul; Han, Yoonsung; Lee, Jinwon; Hong, Jongill

    2008-09-01

    Irradiation of IrMn-based spin valves with 550 eV hydrogen ions increased their giant magnetoresistance and exchange bias by 20% and 60%, respectively. This significant enhancement stems from the strong (111) texture and small mosaic spread of the IrMn antiferromagnet that resulted from the microstructural reconstruction caused by the energy transfer during the bombardment by hydrogen ions, as well as by the narrow dispersion in the exchange bias. Irradiation with the hydrogen ion at low energy can improve the properties of spin valves without resulting in undue degradation in the performance or the microstructure.

  7. High energy ion irradiation induced surface patterning on a SiO2 glass substrate

    NASA Astrophysics Data System (ADS)

    Srivastava, S. K.; Ganesan, K.; Gangopadhyay, P.; Panigrahi, B. K.; Nair, K. G. M.; Tyagi, A. K.

    2014-11-01

    Experimental results about formation of self-organized surface patterns on a silica glass substrate due to irradiations with high energy Au ions at various angles of incidences have been reported in this paper. Pattern formations are found to vary significantly from theoretical predictions. Orientation, growth of ripples and ripple characteristics observed here do not conform to established results of low energy heavy-ion irradiation studies. High energy Au ion-induced effects (e.g., surface stress, mass redistribution and surface current) have been suitably invoked to explain observed phenomena.

  8. Refractive index dispersion of swift heavy ion irradiated BFO thin films using Surface Plasmon Resonance technique

    NASA Astrophysics Data System (ADS)

    Paliwal, Ayushi; Sharma, Savita; Tomar, Monika; Singh, Fouran; Gupta, Vinay

    2016-07-01

    Swift heavy ion irradiation (SHI) is an effective technique to induce defects for possible modifications in the material properties. There is growing interest in studying the optical properties of multiferroic BiFeO3 (BFO) thin films for optoelectronic applications. In the present work, BFO thin films were prepared by sol-gel spin coating technique and were irradiated using the 15 UD Pelletron accelerator with 100 MeV Au9+ ions at a fluence of 1 × 1012 ions cm-2. The as-grown films became rough and porous on ion irradiation. Surface Plasmon Resonance (SPR) technique has been identified as a highly sensitive and powerful technique for studying the optical properties of a dielectric material. Optical properties of BFO thin films, before and after irradiation were studied using SPR technique in Otto configuration. Refractive index is found to be decreasing from 2.27 to 2.14 on ion irradiation at a wavelength of 633 nm. Refractive index dispersion of BFO thin film (from 405 nm to 633 nm) before and after ion radiation was examined.

  9. Strain-dependent Damage in Mouse Lung After Carbon Ion Irradiation

    SciTech Connect

    Moritake, Takashi; Fujita, Hidetoshi; Yanagisawa, Mitsuru; Nakawatari, Miyako; Imadome, Kaori; Nakamura, Etsuko; Iwakawa, Mayumi; Imai, Takashi

    2012-09-01

    Purpose: To examine whether inherent factors produce differences in lung morbidity in response to carbon ion (C-ion) irradiation, and to identify the molecules that have a key role in strain-dependent adverse effects in the lung. Methods and Materials: Three strains of female mice (C3H/He Slc, C57BL/6J Jms Slc, and A/J Jms Slc) were locally irradiated in the thorax with either C-ion beams (290 MeV/n, in 6 cm spread-out Bragg peak) or with {sup 137}Cs {gamma}-rays as a reference beam. We performed survival assays and histologic examination of the lung with hematoxylin-eosin and Masson's trichrome staining. In addition, we performed immunohistochemical staining for hyaluronic acid (HA), CD44, and Mac3 and assayed for gene expression. Results: The survival data in mice showed a between-strain variance after C-ion irradiation with 10 Gy. The median survival time of C3H/He was significantly shortened after C-ion irradiation at the higher dose of 12.5 Gy. Histologic examination revealed early-phase hemorrhagic pneumonitis in C3H/He and late-phase focal fibrotic lesions in C57BL/6J after C-ion irradiation with 10 Gy. Pleural effusion was apparent in C57BL/6J and A/J mice, 168 days after C-ion irradiation with 10 Gy. Microarray analysis of irradiated lung tissue in the three mouse strains identified differential expression changes in growth differentiation factor 15 (Gdf15), which regulates macrophage function, and hyaluronan synthase 1 (Has1), which plays a role in HA metabolism. Immunohistochemistry showed that the number of CD44-positive cells, a surrogate marker for HA accumulation, and Mac3-positive cells, a marker for macrophage infiltration in irradiated lung, varied significantly among the three mouse strains during the early phase. Conclusions: This study demonstrated a strain-dependent differential response in mice to C-ion thoracic irradiation. Our findings identified candidate molecules that could be implicated in the between-strain variance to early

  10. New Ion Beam Materials Laboratory for Materials Modification and Irradiation Effects Research

    SciTech Connect

    Zhang, Yanwen; Crespillo, Miguel L; Xue, Haizhou; Jin, Ke; Chen, Chien-Hung; Fontana, Cristiano L; Graham, Dr. Joseph T.; Weber, William J

    2014-11-01

    A new multifunctional ion beam materials laboratory (IBML) has been established at the University of Tennessee, in partnership with Oak Ridge National Laboratory. The IBML is currently equipped with two ion sources, a 3 MV tandem accelerator, three beamlines and three endstations. The IBML is primarily dedicated to fundamental research on ion-solid interaction, ion beam analysis, ion beam modification, and other basic and applied research on irradiation effects in a wide range of materials. An overview of the IBML facility is provided, and experimental results are reported to demonstrate the specific capabilities.

  11. The ionization potentials of atomic ions in laser-irradiated Ar, Kr and Xe clusters

    NASA Astrophysics Data System (ADS)

    Gets, A. V.; Krainov, V. P.

    2006-04-01

    The ionization potentials of atomic ions in laser-irradiated Ar, Kr and Xe clusters are derived as functions of electron temperature. These potentials decrease significantly compared to the case of the isolated atomic ions because of the screening effect by the atomic ions and electrons inside the cluster. The results can be used for derivations of inner ionization by impact collisions of hot electrons with atomic ions and by the static Coulomb field of the ionized cluster. The broadening of atomic states by the quasistatic Holtsmark field of atomic ions is also considered.

  12. New ion beam materials laboratory for materials modification and irradiation effects research

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Crespillo, M. L.; Xue, H.; Jin, K.; Chen, C. H.; Fontana, C. L.; Graham, J. T.; Weber, W. J.

    2014-11-01

    A new multifunctional ion beam materials laboratory (IBML) has been established at the University of Tennessee, in partnership with Oak Ridge National Laboratory. The IBML is currently equipped with two ion sources, a 3 MV tandem accelerator, three beamlines and three endstations. The IBML is primarily dedicated to fundamental research on ion-solid interaction, ion beam analysis, ion beam modification, and other basic and applied research on irradiation effects in a wide range of materials. An overview of the IBML facility is provided, and experimental results are reported to demonstrate the specific capabilities.

  13. Pattern-induced magnetic anisotropy in FePt thin films by ion irradiation

    SciTech Connect

    Jaafar, M.; Sanz, R.; McCord, J.; Jensen, J.; Schaefer, R.; Vazquez, M.; Asenjo, A.

    2011-03-01

    The magnetic properties of FePt thin films have been modified by exposing the samples to irradiation of 4 MeV Cl{sup 2+} ions. Patterned magnetic films, without modified topographical profile, were fabricated by irradiating the films through a shadowing micrometric mask. The structural changes, ascribed to the ion-beam-induced amorphization of the thin films, promote the modification of the magnetic anisotropy. In particular, the out-of-plane component of the magnetization decreases simultaneously with an enhancement of in-plane anisotropy by increasing ion fluence. Moreover, the nonirradiated regions present unexpected anisotropic behavior owing to the stray field of the irradiated regions. The control of this effect, which can have unwished consequences for the patterning of magnetic properties by ion bombardment, needs to be suitably addressed.

  14. Ion irradiation of carbonaceous chondrites as a simulation of space weathering on C-complex asteroids

    NASA Astrophysics Data System (ADS)

    Lantz, C.; Brunetto, R.; Barucci, M. A.; Bachelet, C.; Baklouti, D.; Bourçois, J.; Dartois, E.; Duprat, J.; Duret, P.; Engrand, C.; Godard, M.; Ledu, D.; Mivumbi, O.; Fornasier, S.

    2015-10-01

    We are investigating the effects of space weathering on primitive asteroids using ion irradiation on their meteoritic analogs. To do so, we exposed several carbonaceous chondrites (CV Allende, COs Lancé and Frontier Mountain 95002, CM Mighei, CI Alais, and ungrouped Tagish Lake) to 40 keV He+ ions as a simulation of solar wind irradiation using fluences up to 6.1016 ions/cm2 (implantation platform IRMA at CSNSM Orsay). As a test for our new experimental setup, we also studied samples of olivine and diopside. We confirm the reddening and darkening trends on S-type objects, but carbonaceous chondrites present a continuum of behaviors after ion irradiation as a function of the initial albedo and carbon content: from red to blue and from dark to bright.

  15. Ion irradiation of graphene on Ir(111): From trapping to blistering

    NASA Astrophysics Data System (ADS)

    Herbig, Charlotte; Åhlgren, E. Harriet; Valerius, Philipp; Schröder, Ulrike A.; Martínez-Galera, Antonio J.; Arman, Mohammad A.; Kotakoski, Jani; Knudsen, Jan; Krasheninnikov, Arkady V.; Michely, Thomas

    Graphene grown epitaxially on Ir(111) is irradiated with low energy noble gas ions and the processes induced by atomic collision and subsequent annealing are analyzed using scanning tunneling microscopy, low energy electron diffraction, X-ray photoelectron diffraction and thermal desorption spectroscopy. Upon room temperature ion irradiation graphene amorphizes and recovers its crystalline structure during annealing. The energetic noble gas projectiles are trapped with surprisingly high efficiency under the graphene cover up to extremely high temperatures beyond 1300K. The energy, angle, and ion species dependence of trapping are quantified. At elevated temperatures the trapped gas forms well developed and highly pressurized blisters under the graphene cover. We use molecular dynamics simulations and ab initio calculations to elucidate the trapping mechanism and its thermal robustness. Similar trapping and blistering are observed after ion irradiation of a single layer of hexagonal boron nitride on Ir(111) and we speculate on the generality of the observed phenomena.

  16. Magnetic reversal in ion-irradiated FePt thin films

    NASA Astrophysics Data System (ADS)

    Mougin, A.; Ferré, J.; Plantevin, O.; Cruguel, H.; Fortuna, F.; Bernas, H.; Marty, A.; Beigné, C.; Samson, Y.

    2010-09-01

    Previous work on ion irradiation control of FePt thin film magnetic anisotropy is extended to ultrathin films (2-10 nm). The effects of 30 keV He ion irradiation on the magnetic properties are explored as a function of ion fluence and film thickness. Depending on their growth conditions, the thinnest films exhibit different magnetic properties. Although this affects their final magnetic behaviour, we show that after irradiation at 300 °C the easy magnetization axis may rotate entirely from in-plane to out-of-plane at very low fluences, e.g. 2 × 1013 He+ cm-2 on 5 nm thick film. This demonstrates the extreme sensitivity of the magnetic anisotropy to ion-induced local L10 ordering. Under these conditions, ultrathin films may exhibit perfectly square hysteresis loops with 100% remanent magnetization and low coercivity.

  17. Producing metastable nanophase with sharp interface by means of focused ion beam irradiation

    SciTech Connect

    Barna, Arpad; Kotis, Laszlo; Labar, Janos; Osvath, Zoltan; Toth, Attila L.; Menyhard, Miklos; Zalar, Anton; Panjan, Peter

    2009-02-15

    Amorphous carbon/nickel double layers were irradiated by 30 keV Ga{sup +} ions via focused ion beam. The effect of irradiation on the concentration distribution of all constituents was studied by Auger electron spectroscopy depth profiling and cross sectional transmission electron microscopy, while the morphology change of the sample was determined by atomic force microscopy. The Ga{sup +} ion irradiation results in the formation of metastable Ni{sub 3}C layer with a uniform thickness. The C/Ni{sub 3}C and Ni{sub 3}C/Ni interfaces were found to be sharp up to a fluence of 200 Ga{sup +} ions/nm{sup 2}.

  18. 84 MeV C-ions irradiation effects on Zr-45Ti-5Al-3V alloy

    NASA Astrophysics Data System (ADS)

    Wang, Weipeng; Li, Zhengcao; Zhang, Zhengjun; Zhang, Chonghong

    2014-09-01

    Newly developed Zr-45Ti-5Al-3V alloy were irradiated by 84 MeV carbon ions with doses of 4 * 1015 ions/cm2 and 12 * 1015 ions/cm2, respectively. XRD, SEM, TEM, SAD and tensile tests were performed to study the microstructural evolution and mechanical properties modification upon high energy carbon ion irradiation. XRD patterns show no phase change while the diffraction peak position and intensity vary with irradiation doses. Tensile tests verify monotonic change of alloy strengths and elongations upon irradiation. Microstructure observations of the irradiated samples reveal the irradiation-induced precipitation of (Zr,Ti)3C2, which was believed contributing to the alloy hardening. Superlattice was discovered by the SAD patterns of original and irradiated samples and the high energy C-ions implantation was demonstrated to promote the disorder-order transition by introducing lattice defects.

  19. Ion irradiation induced solid-state amorphous reaction in Ni/Ti multilayers

    NASA Astrophysics Data System (ADS)

    Milosavljević, Momir; Toprek, Dragan; Obradović, Marko; Grce, Ana; Peruško, Davor; Dražič, Goran; Kovač, Janez; Homewood, Kevin P.

    2013-03-01

    The effects of Ar ion irradiation on interfacial reactions induced in Ni/Ti multilayers were investigated. Structures consisting of 10 alternate Ni (˜26 nm) and Ti (˜20 nm) layers of a total thickness ˜230 nm were deposited by ion sputtering on Si (1 0 0) wafers. Argon irradiations were done at 180 keV, to the doses of 1-6 × 1016 ions/cm2, the samples being held at room temperature. The projected implanted ion range is 86 ± 36 nm, maximum energy loss is closer to the surface, and maximum displacements per atom (dpa) from 47 to 284 for Ni and 26 to 156 for Ti. Characterizations of samples were performed by transmission electron microscopy (TEM) and Rutherford backscattering spectrometry (RBS). It is shown that ion irradiation induced a progressed intermixing in the mostly affected zone already for the lowest dose, the thickness of the mix increasing linearly with the irradiation dose. The mixed phase is fully amorphous, starting with a higher concentration of Ni (which is the diffusing species) from the initial stages, and saturating at Ni:Ti˜66:34. A thick amorphous layer (˜127 nm) formed towards the surface region of the structure for the irradiation dose of 4 × 1016 ions/cm2 remains stable with increasing the dose to 6 × 1016 ions/cm2, which introduces up to 6-7 at.% of Ar within the mix. The results are discussed in light of the existing models. They can be interesting for introducing a selective and controlled solid-state reaction and towards further studies of ion irradiation stability of amorphous Ni-Ti phase.

  20. TEM, XRD and nanoindentation characterization of Xenon ion irradiation damage in austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Huang, H. F.; Li, J. J.; Li, D. H.; Liu, R. D.; Lei, G. H.; Huang, Q.; Yan, L.

    2014-11-01

    Cross-sectional and bulk specimens of a 20% cold-worked 316 austenitic stainless steel (CW 316 SS) has been characterized by TEM, XRD and nanoindentation to determine the microstructural evolution and mechanical property changes of 316 SS after irradiation with 7 MeV Xe26+ ions. TEM results reveal the presence of dislocation loops with a number density of approximately 3 × 1022 m-3 and sizes between 3 to 10 nm due to the collapse of vacancy rich cores inside displacement cascades. Peak broadening observed in XRD diffraction patters reveal systematic changes to lattice parameters due to irradiation. The calculated indentation values in irradiated 316 SS were found to be much higher in comparison to the unirradiated specimen, indicating the dose dependent effect of irradiation on hardness. The relationship between irradiation induced microstructural evolution and the changes to the mechanical properties of CW 316 SS are discussed in the context of fluence and irradiation temperature.

  1. MeV Au Ion Irradiation in Silicon and Nanocrystalline Zirconia Film Deposited on Silicon Substrate

    SciTech Connect

    Chang, Yongqin; Zhang, Yanwen; Zhu, Zihua; Edmondson, Philip D.; Weber, William J.

    2012-09-01

    Nanocrystalline zirconia (ZrO2) film with thickness of 305 nm deposited on a silicon substrate was irradiated with 2 MeV Au ions to different fluences at different temperatures. The implanted ion profiles were measured by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and simulated using the stopping and range of ions inmatter (SRIM) code, respectively. The experimental results show that a large fraction of the incident Au ions penetrates through the ZrO2 film and are deposited into the Si substrate. At the interface of ZrO2 and Si, a sudden decrease of Au concentration is observed due to the much larger scattering cross section of Au in ZrO2 than in Si. The depth profile of the Au ions is measured in both the ZrO2 films and the Si substrates, and the results show that the Au distribution profiles do not exhibit a dependence on irradiation temperature. The local Au concentration increases proportionally with the irradiation fluence, suggesting that no thermal or irradiation-induced redistribution of the implanted Au ions. However, the Au concentration in the ZrO2 films, as determined by SIMS, is considerably lower than that predicted by the SRIM results, and the penetration depth from the SIMS measurements is much deeper than that from the SRIM predictions. These observations can be explained by an overestimation of the electronic stopping power, used in the SRIM program, for heavy incident ions in light targets. Over-estimation of the heavy-ion electronic stopping power may lead to errors in local dose calculation and underestimation of the projected range of slow heavy ions in targets that contain light elements. A quick estimate based on a reduced target density may be used to compensate the overestimation of the electronic stopping power in the SRIM program to provide better ion profile prediction.

  2. The loss of boron in ultra-shallow boron implanted Si under heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Pelicon, P.; El Bouanani, M.; Prasad, G. V. R.; Razpet, A.; Simcic, J.; Guo, B. N.; Birt, D.; Duggan, J. L.; McDaniel, F. D.

    2006-08-01

    Heavy ion impact has been known to cause a loss of light elements from the near-surface region of the irradiated sample. One of the possible approaches to a better understanding of the processes responsible for the release of specific elements is to irradiate shallow-implanted samples, which exhibit a well-known depth distribution of the implanted species. In this work, the samples studied were produced by implantation of Si wafers with 11 B at implantation energies of 250 and 500 eV and fluence of 1.0x10(15) atoms/cm 2 . Elastic Recoil Detection Analysis was applied to monitor the remnant boron fluence in the sample. Irradiation of the samples by a 14.2 (MeVF4+)-F-19 beam resulted in a slow decrease of boron remnant fluence with initial loss rates of the order of 0.05 B atom per impact ion. Under irradiation with 12 (MeVS3+)-S-32 ions, the remnant boron fluence in Si decreased exponentially with a much faster loss rate of boron and became constant after a certain heavy ion irradiation dose. A simple model, which assumes a finite desorption range and corresponding depletion of the near-surface region, was used to describe the observations. The depletion depths under the given irradiation conditions were calculated from the measured data.

  3. Microstructural evolution of RPV steels under proton and ion irradiation studied by positron annihilation spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Wu, Y. C.; Liu, X. B.; Wang, R. S.; Nagai, Y.; Inoue, K.; Shimizu, Y.; Toyama, T.

    2015-03-01

    The microstructural evolution of reactor pressure vessel (RPV) steels induced by proton and heavy ion irradiation at low temperature (∼373 K) has been investigated using positron annihilation spectroscopy (PAS), atom probe tomography (APT), transmission electron microscopy (TEM) and nanoindentation. The PAS results indicated that both proton and heavy ion irradiation produce a large number of matrix defects, which contain small-size defects such as vacancies, vacancy-solute complexes, dislocation loops, and large-size vacancy clusters. In proton irradiated RPV steels, the size and number density of vacancy cluster defects increased rapidly with increasing dose due to the migration and agglomeration of vacancies. In contrast, for Fe ion irradiated steels, high density, larger size vacancy clusters can be easily induced at low dose, showing saturation in PAS response with increasing dose. No clear precipitates, solute-enriched clusters or other forms of solute segregation were observed by APT. Furthermore, dislocation loops were observed by TEM after 1.0 dpa, 240 keV proton irradiation, and an increase of the average nanoindentation hardness was found. It is suggested that ion irradiation produces many point defects and vacancy cluster defects, which induce the formation of dislocation loops and the increase of nanoindentation hardness.

  4. Grain Growth and Phase Stability of Nanocrystalline Cubic Zirconia under Ion Irradiation

    SciTech Connect

    Zhang, Yanwen; Jiang, Weilin; Wang, Chongmin; Namavar, Fereydoon; Edmondson, Philip D.; Zhu, Zihua; Gao, Fei; Lian, Jie; Weber, William J

    2010-01-01

    Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. The loss of oxygen suggests a significant increase of oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.

  5. Disorder and cluster formation during ion irradiation of Au nanoparticles in SiO2

    NASA Astrophysics Data System (ADS)

    Kluth, P.; Johannessen, B.; Foran, G. J.; Cookson, D. J.; Kluth, S. M.; Ridgway, M. C.

    2006-07-01

    Au nanoparticles (NPs) have been formed by ion beam synthesis in 600nm thin SiO2 . Subsequently the NPs were irradiated with 2.3MeV Sn ions at liquid nitrogen temperature. Samples were analyzed using extended x-ray absorption fine structure (EXAFS) spectroscopy and small angle x-ray scattering (SAXS) as a function of Sn irradiation dose. Transmission electron microscopy shows that the NPs largely retain their spherical shape upon irradiation. However, we observe a reduction in average NP size and a concomitant significant narrowing of the size distribution with increasing irradiation dose as consistent with inverse Ostwald ripening. At lower irradiation doses, significant structural disorder is apparent with an effective bond length expansion as consistent with amorphous material. At higher irradiation doses, EXAFS measurements indicate dissolution of a significant fraction of Au from the NPs into the SiO2 matrix (as monomers) and the formation of small Au clusters (dimers, trimers, etc.). We estimate the volume fraction of such monomers/clusters. Ion irradiation thus yields disordering then dissolution of Au NPs.

  6. Physical and biological properties of the ion beam irradiated PMMA-based composite films

    NASA Astrophysics Data System (ADS)

    Shanthini, G. M.; Martin, Catherine Ann; Sakthivel, N.; Veerla, Sarath Chandra; Elayaraja, K.; Lakshmi, B. S.; Asokan, K.; Kanjilal, D.; Kalkura, S. Narayana

    2015-02-01

    Polymethyl methacrylate (PMMA) and PMMA-hydroxyapatite (PMMA-HAp) composite films, prepared by the solvent evaporation method were irradiated with 100 MeV Si7+ ions. Crystallographic, morphological and the functional groups of the pristine and irradiated samples were studied using glancing incident X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) respectively. SEM reveals the creation of pores, along with an increase in porosity and cluster size on irradiation. Decrease in crystalline nature and crystallite size with an increase in ion fluence was observed from GIXRD patterns. The surface roughness and the wettability of the material were also enhanced, which could favour the cell-material interaction. The irradiated samples adsorbed significantly greater amount of proteins than pristine. Also, irradiation does not produce any toxic byproducts or leachants, and maintains the viability of 3T3 cells. The response of the irradiated samples towards biomedical applications was demonstrated by the improved antimicrobial activity, haemocompatibility and cytocompatibility. Swift heavy ion irradiation (SHI) could be an effective tool to modify and engineer the surface properties of the polymers to enhance the biocompatibility.

  7. Morphological and biochemical responses of Oryza sativa L. (cultivar MR219) to ion beam irradiation*

    PubMed Central

    Ling, Anna Pick Kiong; Ung, Ying Chian; Hussein, Sobri; Harun, Abdul Rahim; Tanaka, Atsushi; Yoshihiro, Hase

    2013-01-01

    Objective: Heavy ion beam, which has emerged as a new mutagen in the mutation breeding of crops and ornamental plants, is expected to result in the induction of novel mutations. This study investigates the morphological and biochemical responses of Oryza sativa toward different doses of carbon ion beam irradiation. Methods: In this study, the dry seeds of O. sativa were irradiated at 0, 20, 40, 60, 80, 100, and 120 Gy, followed by in-vitro germination under controlled conditions. Morphological and biochemical studies were conducted to investigate the morphological and physiological responses of O. sativa towards ion beam irradiation. Results: The study demonstrated that low doses (10 Gy) of ion beam have a stimulating effect on the height, root length, and fresh weight of the plantlets but not on the number of leaves. Meanwhile, doses higher than 10 Gy caused reductions in all the morphological parameters studied as compared to the control samples. The highest total soluble protein content [(2.11±0.47) mg/g FW] was observed in plantlets irradiated at 20 Gy. All irradiated plantlets were found to have 0.85% to 58.32% higher specific activity of peroxidase as compared to the control samples. The present study also revealed that low doses of ion beam (10 and 20 Gy) had negligible effect on the total chlorophyll content of O. sativa plantlets while 40 Gy had a stimulating effect on the chlorophyll content. Plantlets irradiated between 40 to 120 Gy were shown to be 0.38% to 9.98% higher in total soluble nitrogen content which, however, was not significantly different from the control samples. Conclusions: Carbon ion beam irradiation administered at low to moderate doses of 10 to 40 Gy may induce O. sativa mutants with superior characteristics. PMID:24302713

  8. TiO2 films photocatalytic activity improvements by swift heavy ions irradiation

    NASA Astrophysics Data System (ADS)

    Rafik, Hazem; Mahmoud, Izerrouken; Mohamed, Trari; Abdenacer, Benyagoub

    2014-08-01

    TiO2 thin films synthesized by sol-gel on glass substrates are irradiated by 90 MeV Xe ions at various fluences and room temperature under normal incidence. The structural, electrical, optical and surface topography properties before and after Xe ions irradiation are investigated. X-ray diffraction (XRD) reveals that the crystallinity is gradually destroyed, and the films become amorphous above 5×1012 ions/cm2. The band gap is not affected by Xe ions irradiation as evidenced from the optical measurements. By contrast, the conductivity increases with raising Xe fluence. The energy band diagram established from the electrochemical characterization shows the feasibility of TiO2 films for the photo-electrochemical chromate reduction. Xe ion irradiation results in enhanced photocatalytic activity in aquatic medium, evaluated by the reduction of Cr(VI) into trivalent state. TiO2 films irradiated at 1013 Xe/cm2 exhibit the highest photoactivity; 69% of chromate (10 ppm) is reduced at pH ~3 after 4 h of exposure to sunlight (1120 mW cm-2) with a quantum yield of 0.06%.

  9. Modeling injected interstitial effects on void swelling in self-ion irradiation experiments

    NASA Astrophysics Data System (ADS)

    Short, M. P.; Gaston, D. R.; Jin, M.; Shao, L.; Garner, F. A.

    2016-04-01

    Heavy ion irradiations at high dose rates are often used to simulate slow and expensive neutron irradiation experiments. However, many differences in the resultant modes of damage arise due to unique aspects of heavy ion irradiation. One such difference was recently shown in pure iron to manifest itself as a double peak in void swelling, with both peaks located away from the region of highest displacement damage. In other cases involving a variety of ferritic alloys there is often only a single peak in swelling vs. depth that is located very near the ion-incident surface. We show that these behaviors arise due to a combination of two separate effects: 1) suppression of void swelling due to injected interstitials, and 2) preferential sinking of interstitials to the ion-incident surface, which are very sensitive to the irradiation temperature and displacement rate. Care should therefore be used in collection and interpretation of data from the depth range outside the Bragg peak of ion irradiation experiments, as it is shown to be more complex than previously envisioned.

  10. Influence of irradiation spectrum and implanted ions on the amorphization of ceramics

    SciTech Connect

    Zinkle, S.J.; Snead, L.L.

    1996-04-01

    Amorphization cannot be tolerated in ceramics proposed for fusion energy applications due to the accompanying large volume change ({approx} 15% in SiC) and loss of strength. Ion beam irradiations at temperatures between 200 K and 450 K were used to examine the likelihood of amorphization in ceramics being considered for the structure (SiC) and numerous diagnostic and plasma heating systems (MgAl{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, MgO, Si{sub 3}N{sub 4}) in fusion energy systems. The microstructures were examined following irradiation using cross-section transmission electron microscopy. The materials in this study included ceramics with predominantly covalent bonding (SiC, Si{sub 3}N{sub 4}) and predominantely ionic bonding (MgAl{sub 2}O{sub 4}, Al{sub 2}O{sub 3}, MgO). The samples were irradiated with a variety of ion beams (including some simultaneous dual ion beam irradiations) in order to investigate possible irradiation spectrum effects. The ion energies were >0.5 MeV in all cases, so that the displacement damage effects could be examined in regions well separated from the implanted ion region.

  11. Biodamage via shock waves initiated by irradiation with ions.

    PubMed

    Surdutovich, Eugene; Yakubovich, Alexander V; Solov'yov, Andrey V

    2013-01-01

    Radiation damage following the ionising radiation of tissue has different scenarios and mechanisms depending on the projectiles or radiation modality. We investigate the radiation damage effects due to shock waves produced by ions. We analyse the strength of the shock wave capable of directly producing DNA strand breaks and, depending on the ion's linear energy transfer, estimate the radius from the ion's path, within which DNA damage by the shock wave mechanism is dominant. At much smaller values of linear energy transfer, the shock waves turn out to be instrumental in propagating reactive species formed close to the ion's path to large distances, successfully competing with diffusion. PMID:23411473

  12. Preparation of ion-track membranes of poly( p-phenylene terephthalamide): Control of pore shape by irradiation with different ion beams

    NASA Astrophysics Data System (ADS)

    Suzuki, Yasuyuki; Yamaki, Tetsuya; Koshikawa, Hiroshi; Asano, Masaharu; Voss, Kay-Obbe; Neumann, Reinhard; Yoshida, Masaru

    2007-07-01

    The preparation of ion-track membranes of thermally stable poly( p-phenylene terephthalamide) (PPTA) was performed by ion beam irradiation followed by chemical etching with a sodium hypochlorite solution. Cylindrical pores were observed in the membrane irradiated with 197Au and 238U ions at an energy of 11.1 MeV/n. In contrast, funnel shape pores appeared in the membrane irradiated with 84Kr, 102Ru and 129Xe ion at energies of 6.2, 3.6 and 3.5 MeV/n, respectively. The 197Au and 238U ion irradiation was found to exhibit more than four times larger sensitivity to the track etching under the same etching conditions. Consequently, the pore shape can be controlled by the masses and energies of the irradiated ions, in close relation to the etching sensitivity of the track.

  13. Space Plasma Ion Processing of Ilmenite in the Lunar Soil: Insights from In-Situ TEM Ion Irradiation Experiments

    NASA Technical Reports Server (NTRS)

    Christoffersen, R.; Keller, L. P.

    2007-01-01

    Space weathering on the moon and asteroids results largely from the alteration of the outer surfaces of regolith grains by the combined effects of solar ion irradiation and other processes that include deposition of impact or sputter-derived vapors. Although no longer considered the sole driver of space weathering, solar ion irradiation remains a key part of the space weathering puzzle, and quantitative data on its effects on regolith minerals are still in short supply. For the lunar regolith, previous transmission electron microscope (TEM) studies performed by ourselves and others have uncovered altered rims on ilmenite (FeTiO3) grains that point to this phase as a unique "witness plate" for unraveling nanoscale space weathering processes. Most notably, the radiation processed portions of these ilmenite rims consistently have a crystalline structure, in contrast to radiation damaged rims on regolith silicates that are characteristically amorphous. While this has tended to support informal designation of ilmenite as a "radiation resistant" regolith mineral, there are to date no experimental data that directly and quantitatively compare ilmenite s response to ion radiation relative to lunar silicates. Such data are needed because the radiation processed rims on ilmenite grains, although crystalline, are microstructurally and chemically complex, and exhibit changes linked to the formation of nanophase Fe metal, a key space weathering process. We report here the first ion radiation processing study of ilmenite performed by in-situ means using the Intermediate Voltage Electron Microscope- Tandem Irradiation facility (IVEM-Tandem) at Argonne National Laboratory. The capability of this facility for performing real time TEM observations of samples concurrent with ion irradiation makes it uniquely suited for studying the dose-dependence of amorphization and other changes in irradiated samples.

  14. Heavy ion irradiation induced dislocation loops in AREVA's M5® alloy

    NASA Astrophysics Data System (ADS)

    Hengstler-Eger, R. M.; Baldo, P.; Beck, L.; Dorner, J.; Ertl, K.; Hoffmann, P. B.; Hugenschmidt, C.; Kirk, M. A.; Petry, W.; Pikart, P.; Rempel, A.

    2012-04-01

    Pressurized water reactor (PWR) Zr-based alloy structural materials show creep and growth under neutron irradiation as a consequence of the irradiation induced microstructural changes in the alloy. A better scientific understanding of these microstructural processes can improve simulation programs for structural component deformation and simplify the development of advanced deformation resistant alloys. As in-pile irradiation leads to high material activation and requires long irradiation times, the objective of this work was to study whether ion irradiation is an applicable method to simulate typical PWR neutron damage in Zr-based alloys, with AREVA's M5® alloy as reference material. The irradiated specimens were studied by electron backscatter diffraction (EBSD), positron Doppler broadening spectroscopy (DBS) and in situ transmission electron microscopy (TEM) at different dose levels and temperatures. The irradiation induced microstructure consisted of - and -type dislocation loops with their characteristics corresponding to typical neutron damage in Zr-based alloys; it can thus be concluded that heavy ion irradiation under the chosen conditions is an excellent method to simulate PWR neutron damage.

  15. Response of nanostructured ferritic alloys to high-dose heavy ion irradiation

    SciTech Connect

    Parish, Chad M.; White, Ryan M.; LeBeau, James M.; Miller, Michael K.

    2014-02-01

    A latest-generation aberration-corrected scanning/transmission electron microscope (STEM) is used to study heavy-ion-irradiated nanostructured ferritic alloys (NFAs). Results are presented for STEM X-ray mapping of NFA 14YWT irradiated with 10 MeV Pt to 16 or 160 dpa at -100°C and 750°C, as well as pre-irradiation reference material. Irradiation at -100°C results in ballistic destruction of the beneficial microstructural features present in the pre-irradiated reference material, such as Ti-Y-O nanoclusters (NCs) and grain boundary (GB) segregation. Irradiation at 750°C retains these beneficial features, but indicates some coarsening of the NCs, diffusion of Al to the NCs, and a reduction of the Cr-W GB segregation (or solute excess) content. Ion irradiation combined with the latest-generation STEM hardware allows for rapid screening of fusion candidate materials and improved understanding of irradiation-induced microstructural changes in NFAs.

  16. Dynamical response of helium bubble motion to irradiation with high-energy self-ions in aluminum at high temperature.

    SciTech Connect

    Ono, K.; Miyamoto, M.; Arakawa, K.; Birtcher, R. C.; Materials Science Division; Shimane Univ.; Osaka Univ.

    2009-02-21

    Brownian-type motion of helium bubbles in aluminum and its dynamical response to irradiation with 100-keV Al{sup +} ions at high temperatures has been studied using in situ irradiation and transmission electron microscopy. It is found that, for most bubbles, the Brownian-type motion is retarded under irradiation, while the mobility returns when the irradiation is stopped. In contrast, under irradiation, a small number of bubbles display exceptionally rapid motion associated with the change in bubble size. These effects are discussed in terms of the dynamical interaction of helium bubbles with cascade damage formed by the high-energy self-ion irradiation.

  17. Development of an ion microbeam system for irradiating single plant cell[s].

    PubMed

    Yokota, Yuichiro; Funayama, Tomoo; Kobayashi, Yasuhiko; Sakashita, Tetsuya; Wada, Seiichi; Hase, Yoshihiro; Shikazono, Naoya; Tanaka, Atsushi; Inoue, Masayoshi

    2003-12-01

    An ion microbeam system for irradiating single plant cells was developed to analyze exact biological effects of ion beams. Tobacco BY-2 protoplasts were used as a model of single plant cells. Protoplasts were cultured in thin agarose medium on a specially designed irradiation-vessel, which has a CR-39 nuclear track detector (a 100-micrometer thick sheet). The colony formation rate of unirradiated protoplasts was 22.7 +/- 6.7% (mean +/- SE of 3 different experiments) after a month of culture. Protoplasts were irradiated with programmed numbers of 18.3 MeV/u carbon ions that had been collimated by a 20-micrometer phi micro-aperture. After the irradiation, the positions within the protoplasts that were hit with ions were accurately determined by etching the CR-39 sheet in 13.4M KOH solution at 27 degrees centigrade for 9 h. The hit rate of the carbon ion microbeam, i.e., the percent of the ion particles that hit the protoplast that they were aimed at, was 56.9 +/- 2.4% (mean +/- SE of 7 different replications). PMID:15136752

  18. Measurement of ion species in high current ECR H+/D+ ion source for IFMIF (International Fusion Materials Irradiation Facility)

    NASA Astrophysics Data System (ADS)

    Shinto, K.; Senée, F.; Ayala, J.-M.; Bolzon, B.; Chauvin, N.; Gobin, R.; Ichimiya, R.; Ihara, A.; Ikeda, Y.; Kasugai, A.; Kitano, T.; Kondo, K.; Marqueta, A.; Okumura, Y.; Takahashi, H.; Valette, M.

    2016-02-01

    Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H+) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D+) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H+ ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H+/D+ ratio estimated by the emittance monitor was more than 90% at those extraction currents.

  19. Formation of diamond in carbon onions under MeV ion irradiation

    NASA Astrophysics Data System (ADS)

    Wesolowski, P.; Lyutovich, Y.; Banhart, F.; Carstanjen, H. D.; Kronmüller, H.

    1997-10-01

    Spherical carbon onions are generated by irradiating graphitic carbon soot with Ne+ ions of 3 MeV energy. Under continued irradiation, a transformation of their cores to cubic diamond crystals is observed. In comparison to earlier electron irradiation experiments, the yield of diamond is much higher. The output of the irradiation experiment is characterized by electron microscopy and electron energy loss spectroscopy. Knock-on displacements of carbon atoms by Ne+ ions are assumed to be responsible for a self-compression of the onions, leading to the nucleation of diamond in their cores. The increased diamond yield is explained by the higher displacement cross-section, the higher energy transfer, and the higher total beam current on the specimen.

  20. Surface reformation and electro-optical characteristics of liquid crystal alignment layers using ion beam irradiation

    SciTech Connect

    Oh, Byeong-Yun; Lee, Kang-Min; Kim, Byoung-Yong; Kim, Young-Hwan; Han, Jin-Woo; Han, Jeong-Min; Lee, Sang-Keuk; Seo, Dae-Shik

    2008-09-15

    The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies were investigated as a substitute for rubbing technology. Various pretilt angles were created on the IB-irradiated polyimide (PI) surfaces after IB irradiation, but the Ar ions did not alter the morphology on the PI surface, indicating that the pretilt angle was not due to microgrooves. The chemical bonding states of the IB-irradiated PI surfaces were analyzed in detail by x-ray photoelectron spectroscopy to verify the compositional behavior for the LC alignment. Chemical structure analysis showed that the alignment ability of LCs was due to the preferential reorientation of the carbon network due to the breaking of C=O double bonds in the imide ring parallel to the incident IB direction. The potential of applying nonrubbing technology to display devices was further supported by the superior electro-optical characteristics compared to rubbed PI.

  1. Formation of diamond in carbon onions under MeV ion irradiation

    SciTech Connect

    Wesolowski, P.; Lyutovich, Y.; Banhart, F.; Carstanjen, H.D.; Kronmueller, H.

    1997-10-01

    Spherical carbon onions are generated by irradiating graphitic carbon soot with Ne{sup +} ions of 3 MeV energy. Under continued irradiation, a transformation of their cores to cubic diamond crystals is observed. In comparison to earlier electron irradiation experiments, the yield of diamond is much higher. The output of the irradiation experiment is characterized by electron microscopy and electron energy loss spectroscopy. Knock-on displacements of carbon atoms by Ne{sup +} ions are assumed to be responsible for a self-compression of the onions, leading to the nucleation of diamond in their cores. The increased diamond yield is explained by the higher displacement cross-section, the higher energy transfer, and the higher total beam current on the specimen. {copyright} {ital 1997 American Institute of Physics.}

  2. Characterization of biodegradable polymers irradiated with swift heavy ions

    NASA Astrophysics Data System (ADS)

    Salguero, N. G.; del Grosso, M. F.; Durán, H.; Peruzzo, P. J.; Amalvy, J. I.; Arbeitman, C. R.; García Bermúdez, G.

    2012-02-01

    In view of their application as biomaterials, there is an increasing interest in developing new methods to induce controlled cell adhesion onto polymeric materials. The critical step in all these methods involves the modification of polymer surfaces, to induce cell adhesion, without changing theirs degradation and biocompatibility properties. In this work two biodegradable polymers, polyhydroxybutyrate (PHB) and poly- L-lactide acid (PLLA) were irradiated using carbon and sulfur beams with different energies and fluences. Pristine and irradiated samples were degradated by immersion in a phosphate buffer at pH 7.0 and then characterized. The analysis after irradiation and degradation showed a decrease in the contact angle values and changes in their crystallinity properties.

  3. Mutation induction in bacteria after heavy ion irradiation

    NASA Technical Reports Server (NTRS)

    Horneck, G.; Kozubek, S.

    1994-01-01

    From a compilation of experimental data on the mutagenic effects of heavy ions in bacteria, main conclusions have been drawn as follows: (1) The mutagenic efficacy of heavy ions in bacteria depends on physical and biological variables. Physical variables are the radiation dose, energy and charge of the ion; the biological variables are the bacterial strain, the repair genotype of bacteria, and the endpoint investigated (type of mutation, induction of enzymes related to mutagenesis); (2) The responses on dose or fluence are mainly linear or linear quadratic. The quadratic component, if found for low LET radiation, is gradually reduced with increasing LET; (3) At low values of Z and LET the cross section of mutation induction sigma m (as well as SOS response, sigma sos. and lambda phage induction, sigma lambda versus LET curves can be quite consistently described by a common function which increases up to approximately 100 keV/mu m. For higher LET values, the sigma(m) versus LET curves show the so-called 'hooks' observed also for other endpoints; (4) For light ions (Z is less than or equal to 4), the cross sections mostly decrease with increasing ion energy, which is probably related to the decrease of the specific energy departed by the ion inside the sensitive volume (cell). For ions in the range of Z = 10, sigma(m) is nearly independent on the ion energy. For heavier ions (Z is greater than or equal to 16), sigma(m) increases with the energy up to a maximum or saturation around 10 MeV/u. The increment becomes steeper with increasing atomic number of the ion. It correlates with the increasing track radius of the heavy ion; (5) The mutagenic efficiency per lethal event changes slightly with ion energy, if Z is small indicating a rough correlation between cellular lethality and mutation induction, only. For ions of higher Z this relation increases with energy, indicating a change in the 'mode' of radiation action from 'killing-prone' to 'mutation-prone'; and (6

  4. Characterization of high energy Xe ion irradiation effects in single crystal molybdenum with depth-resolved synchrotron microbeam diffraction

    NASA Astrophysics Data System (ADS)

    Yun, Di; Miao, Yinbin; Xu, Ruqing; Mei, Zhigang; Mo, Kun; Mohamed, Walid; Ye, Bei; Pellin, Michael J.; Yacout, Abdellatif M.

    2016-04-01

    Microbeam X-ray diffraction experiments were conducted at beam line 34-ID of the Advanced Photon Source (APS) on fission fragment energy Xe heavy ion irradiated single crystal Molybdenum (Mo). Lattice strain measurements were obtained with a depth resolution of 0.7 μm, which is critical in resolving the peculiar heterogeneity of irradiation damage associated with heavy ion irradiation. Q-space diffraction peak shift measurements were correlated with lattice strain induced by the ion irradiations. Transmission electron microscopy (TEM) characterizations were performed on the as-irradiated materials as well. Nanometer sized Xe bubble microstructures were observed via TEM. Molecular Dynamics (MD) simulations were performed to help interpret the lattice strain measurement results from the experiment. This study showed that the irradiation effects by fission fragment energy Xe ion irradiations can be collaboratively understood with the depth resolved X-ray diffraction and TEM measurements under the assistance of MD simulations.

  5. Evaluation of hardening behaviors in ion-irradiated Fe-9Cr and Fe-20Cr alloys by nanoindentation technique

    NASA Astrophysics Data System (ADS)

    Li, Shilei; Wang, Yanli; Dai, Xianyuan; Liu, Fang; Li, Jinyu; Wang, Xitao

    2016-09-01

    The ion irradiation hardening behaviors of Fe-9 wt% Cr and Fe-20 wt% Cr model alloys were investigated by nanoindentation technique. The specimens were irradiated with 3 MeV Fe11+ ions at room temperature up to 1 and 5 dpa for Fe-9Cr alloy and 1 and 2.5 for Fe-20Cr alloy. The ratio of average hardness in the same depth of irradiated and unirradiated (Hirr. av/Hunirr. av) was used to determine the critical indentation depth hcrit to eliminate the softer substrate effect. The Nix-Gao model was used to explain the indentation size effect. Irradiation hardening is clearly observed in both Fe-9Cr alloy and Fe-20Cr alloy after ion irradiation. The differences of ISE and irradiation hardening behaviors between Fe-9Cr and Fe-20Cr alloys are considered to be due to their different microstructures and microstructural evolution under ion irradiation.

  6. Protective effects of shikonin on brain injury induced by carbon ion beam irradiation in mice.

    PubMed

    Gan, Lu; Wang, Zhen Hua; Zhang, Hong; Zhou, Rong; Sun, Chao; Liu, Yang; Si, Jing; Liu, Yuan Yuan; Wang, Zhen Guo

    2015-02-01

    Radiation encephalopathy is the main complication of cranial radiotherapy. It can cause necrosis of brain tissue and cognitive dysfunction. Our previous work had proved that a natural antioxidant shikonin possessed protective effect on cerebral ischemic injury. Here we investigated the effects of shikonin on carbon ion beam induced radiation brain injury in mice. Pretreatment with shikonin significantly increased the SOD and CAT activities and the ratio of GSH/GSSG in mouse brain tissues compared with irradiated group (P<0.01), while obviously reduced the MDA and PCO contents and the ROS levels derived from of the brain mitochondria. The shikonin also noticeably improved the spatial memory deficits caused by carbon ion beam irradiation. All results demonstrated that shikonin could improve the irradiated brain injury which might resulted from its modulation effects on the oxidative stress induced by the 12C6+ ion beam. PMID:25716567

  7. Manipulation of transport hysteresis on graphene field effect transistors with Ga ion irradiation

    SciTech Connect

    Wang, Quan; Liu, Shuai; Ren, Naifei

    2014-09-29

    We have studied the effect of Ga ion irradiation on the controllable hysteretic behavior of graphene field effect transistors fabricated on Si/SO{sub 2} substrates. The various densities of defects in graphene were monitored by Raman spectrum. It was found that the Dirac point shifted to the positive gate voltage constantly, while the hysteretic behavior was enhanced first and then weakened, with the dose of ion irradiation increasing. By contrasting the trap charges density induced by dopant and the total density of effective trap charges, it demonstrated that adsorbate doping was not the decisive factor that induced the hysteretic behavior. The tunneling between the defect sites induced by ion irradiation was also an important cause for the hysteresis.

  8. Particle irradiation and electron work function: Fe single crystal bombarded with Ar+ ions

    NASA Astrophysics Data System (ADS)

    Horváth, Ákos; Nagy, Norbert; Schiller, Robert

    2016-07-01

    Accelerated Ar+ ions of 30 keV energy were used to mimic the effect of fast neutrons on Fe single crystal. Both Monte-Carlo calculations and X-ray Photoelectron Spectroscopy (XPS) measurements indicated that the fast ions did not alter the surface causing damage only at several nm depth. The change in the electrode potential, characteristic also to corrosion processes, was determined by the Kelvin method of work function measurement in order to avoid any post-irradiation process. Irradiation with fluences between 5×1014 and 6×1015 cm-2 decreased the electrode potential of the sample by about 60 mV in qualitative agreement with earlier results about the work functions of Fe single crystal and polycrystalline sample. Thus ion irradiation turns the interior of the single crystal into a disordered, polycrystalline substance increasing the crystal's readiness to be corroded.

  9. Swift heavy ion irradiation of metal containing tetrahedral amorphous carbon films

    NASA Astrophysics Data System (ADS)

    Karaseov, P. A.; Protopopova, V. S.; Karabeshkin, K. V.; Shubina, E. N.; Mishin, M. V.; Koskinen, J.; Mohapatra, S.; Tripathi, A.; Avasthi, D. K.; Titov, A. I.

    2016-07-01

    Thin carbon films were grown at room temperature on (0 0 1) n-Si substrate using dual cathode filtered vacuum arc deposition system. Graphite was used as a source of carbon atoms and separate metallic electrode was simultaneously utilized to introduce Ni or Cu atoms. Films were irradiated by 100 MeV Ag7+ ions to fluences in the range 1 × 1010-3 × 1011 cm-2. Rutherford backscattering spectroscopy, Raman scattering, scanning electron microscopy and atomic force microscopy in conductive mode were used to investigate film properties and structure change under irradiation. Some conductive channels having metallic conductivity type were found in the films. Number of such channels is less than number of impinged ions. Presence of Ni and Cu atoms increases conductivity of those conductive channels. Fluence dependence of all properties studied suggests different mechanisms of swift heavy ion irradiation-induced transformation of carbon matrix due to different chemical effect of nickel and copper atoms.

  10. Localized dose delivering by ion beam irradiation for experimental trial of establishing brain necrosis model.

    PubMed

    Takata, Takushi; Kondo, Natsuko; Sakurai, Yoshinori; Tanaka, Hiroki; Hasegawa, Takashi; Kume, Kyo; Suzuki, Minoru

    2015-11-01

    Localized dose delivery techniques to establish a brain radiation necrosis model are described. An irradiation field was designed by using accelerated protons or helium ions with a spread-out Bragg peak. Measurement of the designed field confirmed that a high dose can be confined to a local volume of an animal brain. The irradiation techniques described here are very useful for establishing a necrosis model without existence of extraneous complications. PMID:26454176

  11. Nanoindentation creep study on an ion beam irradiated oxide dispersion strengthened alloy

    NASA Astrophysics Data System (ADS)

    Huang, Zijing; Harris, Adrian; Maloy, Stuart A.; Hosemann, Peter

    2014-08-01

    Oxide dispersion strengthened (ODS) alloys are considered advanced structural materials for nuclear application due to their radiation tolerance and creep resistance. Ion beam irradiation is used to study the property changes due to displacement damage. In this work 1 dpa displacement damage in an ODS was produced followed by a nanoindentation creep study at temperatures up to 600 °C to evaluate the changes in mechanical properties due to irradiation. Converted yield strength (YS) and creep related parameters are reported.

  12. Tamped, split fuel-layer ion-beam target

    SciTech Connect

    Meeker, D.J.; Bangerter, R.O.

    1981-01-01

    A double shelled, split fuel layer target with an outer hydro tamper surrounding the low Z absorber has been designed for ion beam drivers. Results from 1-D computer calculations predict a 5 GeV heavy ion beam could produce gains in excess of 200. The behavior of this target as a function of ion range, tamper thickness and spot size has been studied.

  13. Comprehensive identification of mutations induced by heavy-ion beam irradiation in Arabidopsis thaliana.

    PubMed

    Hirano, Tomonari; Kazama, Yusuke; Ishii, Kotaro; Ohbu, Sumie; Shirakawa, Yuki; Abe, Tomoko

    2015-04-01

    Heavy-ion beams are widely used for mutation breeding and molecular biology. Although the mutagenic effects of heavy-ion beam irradiation have been characterized by sequence analysis of some restricted chromosomal regions or loci, there have been no evaluations at the whole-genome level or of the detailed genomic rearrangements in the mutant genomes. In this study, using array comparative genomic hybridization (array-CGH) and resequencing, we comprehensively characterized the mutations in Arabidopsis thaliana genomes irradiated with Ar or Fe ions. We subsequently used this information to investigate the mutagenic effects of the heavy-ion beams. Array-CGH demonstrated that the average number of deleted areas per genome were 1.9 and 3.7 following Ar-ion and Fe-ion irradiation, respectively, with deletion sizes ranging from 149 to 602,180 bp; 81% of the deletions were accompanied by genomic rearrangements. To provide a further detailed analysis, the genomes of the mutants induced by Ar-ion beam irradiation were resequenced, and total mutations, including base substitutions, duplications, in/dels, inversions, and translocations, were detected using three algorithms. All three resequenced mutants had genomic rearrangements. Of the 22 DNA fragments that contributed to the rearrangements, 19 fragments were responsible for the intrachromosomal rearrangements, and multiple rearrangements were formed in the localized regions of the chromosomes. The interchromosomal rearrangements were detected in the multiply rearranged regions. These results indicate that the heavy-ion beams led to clustered DNA damage in the chromosome, and that they have great potential to induce complicated intrachromosomal rearrangements. Heavy-ion beams will prove useful as unique mutagens for plant breeding and the establishment of mutant lines. PMID:25690092

  14. Large scale silver nanowires network fabricated by MeV hydrogen (H+) ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Honey, S.; Naseem, S.; Ishaq, A.; Maaza, M.; Bhatti, M. T.; Wan, D.

    2016-04-01

    A random two-dimensional large scale nano-network of silver nanowires (Ag-NWs) is fabricated by MeV hydrogen (H+) ion beam irradiation. Ag-NWs are irradiated under H+ ion beam at different ion fluences at room temperature. The Ag-NW network is fabricated by H+ ion beam-induced welding of Ag-NWs at intersecting positions. H+ ion beam induced welding is confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Moreover, the structure of Ag NWs remains stable under H+ ion beam, and networks are optically transparent. Morphology also remains stable under H+ ion beam irradiation. No slicings or cuttings of Ag-NWs are observed under MeV H+ ion beam irradiation. The results exhibit that the formation of Ag-NW network proceeds through three steps: ion beam induced thermal spikes lead to the local heating of Ag-NWs, the formation of simple junctions on small scale, and the formation of a large scale network. This observation is useful for using Ag-NWs based devices in upper space where protons are abandoned in an energy range from MeV to GeV. This high-quality Ag-NW network can also be used as a transparent electrode for optoelectronics devices. Project supported by the National Research Foundation of South Africa (NRF), the French Centre National pour la Recherche Scientifique, iThemba-LABS, the UNESCO-UNISA Africa Chair in Nanosciences & Nanotechnology, the Third World Academy of Science (TWAS), Organization of Women in Science for the Developing World (OWSDW), the Abdus Salam ICTP via the Nanosciences African Network (NANOAFNET), and the Higher Education Commission (HEC) of Pakistan.

  15. Grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation

    SciTech Connect

    Zhang, Yanwen; Jiang, Weilin; Wang, Chong M.; Namavar, Fereydoon; Edmondson, Philip D.; Zhu, Zihua; Gao, Fei; Lian, Jie; Weber, William J.

    2010-11-10

    Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized zirconia (NSZ) in pure cubic phase are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that thermal grain growth is not activated and defect-stimulated grain growth is the dominating mechanism. While cubic phase is perfectly retained and no new phases are identified after the high-dose irradiations, reduction of oxygen in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. Significant increase of oxygen vacancies in nanocrystalline zirconia suggests substantially enhanced oxygen diffusion under ion irradiation, a materials behavior far from equilibrium. The oxygen deficiency may be essential in stabilizing cubic phase to larger grain sizes.

  16. Evaluation of radiation hardening in ion-irradiated Fe based alloys by nanoindentation

    NASA Astrophysics Data System (ADS)

    Liu, Xiangbing; Wang, Rongshan; Ren, Ai; Jiang, Jing; Xu, Chaoliang; Huang, Ping; Qian, Wangjie; Wu, Yichu; Zhang, Chonghong

    2014-01-01

    Nanoindentation in combination with ion irradiation offers the possibility to quantify irradiation hardening due to radiation damage. Irradiation experiments for Fe-1.0wt.%Cu alloys, China A508-3 steels, and 16MND5 steels were carried out at about 100 °C by proton and Fe-ions with the energy of 240 keV, 3 MeV respectively. The constant stiffness measurement (CSM) with a diamond Berkovich indenter was used to obtain the depth profile of hardness. The results showed that under 240 keV proton irradiation (peak damage up to 0.5 dpa), Fe-1.0wt.%Cu alloys exhibited the largest hardening (∼55%), 16MND5 steels resided in medium hardening (∼46%), and China A508-3(2) steels had the least hardening (∼10%). Under 3 MeV Fe ions irradiation (peak damage up to 1.37 dpa), both China A508-3(1) and 16MND5 steels showed the same hardening (∼26%). The sequence of irradiation tolerance for these materials is China A508-3(2) > 16MND5 ≈ China A508-3(1) > Fe-1.0wt.%Cu. Based on the determination of the transition depth, the nominal hardness H0irr was also calculated by Kasada method.

  17. Cation disordering in magnesium aluminate spinel crystals induced by electron or ion irradiation

    NASA Astrophysics Data System (ADS)

    Soeda, Takeshi; Matsumura, Syo; Kinoshita, Chiken; Zaluzec, Nestor J.

    2000-12-01

    Structural changes in magnesium aluminate spinel (MgO · nAl 2O 3) single crystals, which were irradiated with 900 keV electrons or 1 MeV Ne + ions at 873 K, were examined by electron channeling enhanced X-ray microanalysis. Unirradiated MgO · Al 2O 3 has a tendency to form the normal spinel configuration, where Mg 2+ ions and Al 3+ ions occupy mainly the tetrahedral and the octahedral sites, respectively. Electron irradiation induces simple cation disordering between the tetrahedral sites and the octahedral sites in MgO · Al 2O 3. In addition to cation disordering, slight evacuation of cations from the tetrahedral sites to the octahedral sites occurs in a peak-damaged area in MgO · Al 2O 3 irradiated with Ne + ions. In contrast, cation disordering is suppressed in MgO · 2.4Al 2O 3 irradiated with electrons. The structural vacancies, present in the non-stoichiometric compound, appear to be effective in promoting irradiation damage recovery through interstitial-vacancy recombination.

  18. Nanoscale patterning of CrPt3 magnetic thin films by using ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Suharyadi, Edi; Oshima, Daiki; Kato, Takeshi; Iwata, Satoshi

    We have successfully fabricated planar patterned CrPt3 ordered L12 alloy films by Kr+ ion irradiation. Planar-patterned CrPt3 nanodots with various bit sizes from 200 nm to 50 nm were successfully fabricated by 30 keV Kr+ ion irradiation at a dose of 2 × 1014 ions/cm2, where e-beam lithography was used for creating the resist mask. We have confirmed that the nanofabrication process didn't change the magnetic properties of CrPt3 ordered L12 alloy films. As-prepared film exhibited perpendicular hysteresis loop with the coercivity of 5.5 kOe. The typical perpendicular maze domain structure with the stripe structure was clearly seen in as-prepared CrPt3 film. Magnetic force microscopy (MFM) images of patterned CrPt3 nanodots indicated that each un-irradiated bit consists of localized perpendicular magnetic domain structures, which corresponds to perpendicular magnetization direction. Nanodots with bit size ⩽80 nm show either dark or bright contrast, suggesting single domain structure. No magnetic contrast in irradiated space is due to the suppressing of the magnetization by Kr+ ion irradiation.

  19. Effect of swift heavy ion irradiation on bare and coated ZnS quantum dots

    SciTech Connect

    Chowdhury, S. Hussain, A.M.P.; Ahmed, G.A.; Singh, F.; Avasthi, D.K.; Choudhury, A.

    2008-12-01

    The present study compares structural and optical modifications of bare and silica (SiO{sub 2}) coated ZnS quantum dots under swift heavy ion (SHI) irradiation. Bare and silica coated ZnS quantum dots were prepared following an inexpensive chemical route using polyvinyl alcohol (PVA) as the dielectric host matrix. X-ray diffraction (XRD) and transmission electron microscopy (TEM) study of the samples show the formation of almost spherical ZnS quantum dots. The UV-Vis absorption spectra reveal blue shift relative to bulk material in absorption energy while photoluminescence (PL) spectra suggests that surface state and near band edge emissions are dominating in case of bare and coated samples, respectively. Swift heavy ion irradiation of the samples was carried out with 160 MeV Ni{sup 12+} ion beam with fluences 10{sup 12} to 10{sup 13} ions/cm{sup 2}. Size enhancement of bare quantum dots after irradiation has been indicated in XRD and TEM analysis of the samples which has also been supported by optical absorption spectra. However similar investigations on irradiated coated quantum dots revealed little change in quantum dot size and emission. The present study thus shows that the coated ZnS quantum dots are stable upon SHI irradiation compared to the bare one.

  20. Phase stability in thermally-aged CASS CF8 under heavy ion irradiation

    NASA Astrophysics Data System (ADS)

    Li, Meimei; Miller, Michael K.; Chen, Wei-Ying

    2015-07-01

    The stability of the microstructure of a cast austenitic stainless steel (CASS), before and after heavy ion irradiation, was investigated by atom probe tomography (APT). A CF8 ferrite-austenite duplex alloy was thermally aged at 400 °C for 10,000 h. After this treatment, APT revealed nanometer-sized G-phase precipitates and Fe-rich α and Cr-enriched α‧ phase separated regions in the ferrite. The thermally-aged CF8 specimen was irradiated with 1 MeV Kr ions to a fluence of 1.88 × 1019 ions/m2 at 400 °C. After irradiation, APT analysis revealed a strong spatial/dose dependence of the G-phase precipitates and the α-α‧ spinodal decomposition in the ferrite. For the G-phase precipitates, the number density increased and the mean size decreased with increasing dose, and the particle size distribution changed considerably under irradiation. The inverse coarsening process can be described by recoil resolution. The amplitude of the α-α‧ spinodal decomposition in the ferrite was apparently reduced after heavy ion irradiation.

  1. Effect of swift heavy ion irradiation on single- and multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Olejniczak, Andrzej; Skuratov, Vladimir A.

    2014-05-01

    The effect of irradiation with swift heavy ions on the structure and properties of carbon nanotubes was investigated by Raman spectroscopy. It was found that disordering of the system occurred mainly at the surface. No ordering phenomena have been observed over a whole range of both fluences and electronic stopping powers studied. The disorder parameter (i.e., the ratio of the D and G band intensities (ID/IG)) increases non-linearly with the irradiation dose, showing a tendency to saturate at high fluences. The increase in the disorder parameter upon irradiation was proportional to the square root of the ion fluence. The radiation stability of the few-walled nanotubes was ca. 1.6 higher than that of the single-walled ones. The irradiation with both the Xe and Kr ions leads to essentially the same increase in the ID/IG ratio with respect to the deposited electronic energy density. In the case of the Ar ion irradiation, the observed increase in the ID/IG ratio is much lower, suggesting that the electronic stopping power threshold for defects creation in carbon nanotubes is lower than that for graphite.

  2. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation.

    PubMed

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  3. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

    NASA Astrophysics Data System (ADS)

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  4. Silicon ion irradiation effects on the magnetic properties of ion beam synthesized CoPt phase

    SciTech Connect

    Balaji, S.; Amirthapandian, S.; Panigrahi, B. K.; Mangamma, G.; Kalavathi, S.; Gupta, Ajay; Nair, K. G. M.

    2012-06-05

    Ion beam mixing of Pt/Co bilayers using self ion (Pt{sup +}) beam results in formation of CoPt phase. Upon ion beam annealing the ion mixed samples using 4 MeV Si{sup +} ions at 300 deg. C, diffusion of Co towards the Pt/Co interface is observed. The Si{sup +} ion beam rotates the magnetization of the CoPt phase from in plane to out of plane of the film.

  5. Silicon Carbide Power Device Performance Under Heavy-Ion Irradiation

    NASA Technical Reports Server (NTRS)

    Lauenstein, Jean-Marie; Casey, Megan; Topper, Alyson; Wilcox, Edward; Phan, Anthony; Ikpe, Stanley; LaBel, Ken

    2015-01-01

    Heavy-ion induced degradation and catastrophic failure data for SiC power MOSFETs and Schottky diodes are examined to provide insight into the challenge of single-event effect hardening of SiC power devices.

  6. Efficient modification of floral traits by heavy-ion beam irradiation on transgenic Torenia.

    PubMed

    Ohtsubo, Norihiro; Sasaki, Katsutomo; Aida, Ryutaro; Ryuto, Hiromichi; Ichida, Hiroyuki; Hayashi, Yoriko; Abe, Tomoko

    2012-01-01

    While heavy-ion beam irradiation is becoming popular technology for mutation breeding in Japan, the combination with genetic manipulation makes it more convenient to create greater variation in plant phenotypes. We have succeeded in producing over 200 varieties of transgenic torenia (Torenia fournieri Lind.) from over 2,400 regenerated plants by this procedure in only 2 years. Mutant phenotypes were observed mainly in flowers and showed wide variation in colour and shape. Higher mutation rates in the transgenics compared to those in wild type indicate the synergistic effect of genetic manipulation and heavy-ion beam irradiation, which might be advantageous to create greater variation in floral traits. PMID:22351017

  7. Combined High Pressure and Heavy-Ion Irradiation: a Novel Approach

    SciTech Connect

    Lang, M.; Zhang, F; Lian, J; Trautmann, C; Neumann, R; Ewing, R

    2009-01-01

    Swift heavy-ion irradiations of a wide variety of materials have been used to modify and manipulate the properties of solids at the nanoscale. Recently, these high-energy irradiations have been successfully combined with high-pressure experiments. Based on results obtained for zircon (ZrSiO{sub 4}), this paper introduces this new experimental approach involving diamond anvil cells and large ion-accelerator facilities. This technique provides a wide spectrum of geoscience applications from nanoscale simulations of fission-track formation under crustal conditions to phase transitions of radiation-damaged minerals resulting from meteorite impact.

  8. Positron annihilation lifetime characterization of oxygen ion irradiated rutile TiO2

    NASA Astrophysics Data System (ADS)

    Luitel, Homnath; Sarkar, A.; Chakrabarti, Mahuya; Chattopadhyay, S.; Asokan, K.; Sanyal, D.

    2016-07-01

    Ferromagnetic ordering at room temperature has been induced in rutile phase of TiO2 polycrystalline sample by O ion irradiation. 96 MeV O ion induced defects in rutile TiO2 sample has been characterized by positron annihilation spectroscopic techniques. Positron annihilation results indicate the formation of cation vacancy (VTi, Ti vacancy) in these irradiated TiO2 samples. Ab initio density functional theoretical calculations indicate that in TiO2 magnetic moment can be induced either by creating Ti or O vacancies.

  9. Optical waveguides in Yb:SBN crystals fabricated by swift C3+ ion irradiation

    NASA Astrophysics Data System (ADS)

    Liu, Guiyuan; Dong, Ningning; Wang, Jun; Akhmadaliev, Shavkat; Zhou, Shengqiang; Chen, Feng

    2016-01-01

    We report on the fabrication of optical planar waveguides supporting both the TE and TM confinements in Yb:SBN crystal by swift C3+ ions irradiation. A combination of the micro-photoluminescence and micro-Raman investigations have evidenced the presence of lattice distortion, damage and disordering of the SBN network along the ion irradiation path, with these effects being at the basis of the refractive index modification. The enhanced micro-photoluminescence and micro-Raman intensity in the waveguide volumes show the potential application of the obtained waveguides as active laser gain media.

  10. Interaction of deuterium with vacancies induced by ion irradiation in W

    NASA Astrophysics Data System (ADS)

    Xu, Q.; Sato, K.; Cao, X. Z.; Zhang, P.; Wang, B. Y.; Yoshiie, T.; Watanabe, H.; Yoshida, N.

    2013-11-01

    The tritium inventory in plasma-facing materials (PFMs) is an important issue in fusion reactors. Tungsten (W), which is a candidate PFM, has a very low solubility for hydrogen isotopes, but intrinsic and radiation-induced defects can retain a significant amount of hydrogen. A positron annihilation technique was used to investigate the interactions between deuterium (D) and vacancies in W irradiated by Cu ions. The results indicated that vacancies were formed in W after Cu ion irradiation, and that D atoms were trapped by these vacancies.