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Sample records for mev ion bombardment

  1. Effects produced in GaAs by MeV ion bombardment

    International Nuclear Information System (INIS)

    Wie, C.R.

    1985-01-01

    The first part of this thesis presents work performed on the ionizing energy beam induced adhesion enhancement of thin (approx.500 A) Au films on GaAs substrates. The ionizing beam, employed in the present thesis, is the MeV ions (i.e., 16 O, 19 F, and 35 Cl), with energies between 1 and 20 MeV. Using the Scratch test for adhesion measurement, and ESCA for chemical analysis of the film substrate interface, the native oxide layer at the interface is shown to play an important role in the adhesion enhancement by the ionizing radiation. A model is discussed that explains the experimental data on the dependence of adhesion enhancement on the energy which was deposited into electronic processes at the interface. The second part of the thesis presents research results on the radiation damage in GaAs crystals produced by MeV ions. Lattice parameter dilatation in the surface layers of the GaAs crystals becomes saturated after a high dose bombardment at room temperature. The strain produced by nuclear collisions is shown to relax partially due to electronic excitation (with a functional dependence on the nuclear and electronic stopping power of bombarding ions. Data on the GaAs and GaP crystals suggest that low temperature recovery stage defects produce major crystal distortion

  2. Comparison of secondary ion emission induced in silicon oxide by MeV and KeV ion bombardment

    International Nuclear Information System (INIS)

    Allali, H.; Nsouli, B.; Thomas, J.P.; Szymczak, W.; Wittmaack, K.

    1993-09-01

    The surface and near-surface composition of SiO 2 layers, has been investigated by negative secondary ion emission mass spectrometry (SIMS) using MeV and KeV ion bombardment in combination with time-of-flight (TOF) mass analysis. The spectra recorded in the mass range 0-100 u are dominated by surface impurities, notably hydrocarbons and silicon polyanions incorporating H and OH entities. The characteristic (fragmentation) patterns are quite different for light and high-velocity ion impact. In high-velocity TOF-SIMS analysis of P-doped layers, prepared by chemical vapour deposition (CVD), the mass lines at 63 and 79 u are very prominent and appear to correlate with the phosphorus concentration (PO 2 and PO 3 , respectively). It is shown, however, that for unambiguous P analysis one has to use dynamic SIMS or high mass resolution. (author) 11 refs., 5 figs

  3. Exfoliation on stainless steel and inconel produced by 0.8-4 MeV helium ion bombardment

    International Nuclear Information System (INIS)

    Paszti, F.; Mezey, G.; Pogany, L.; Fried, M.; Manuaba, A.; Kotai, E.; Lohner, T.; Pocs, L.

    1982-11-01

    Trying to outline the energy dependence of surface deformations such as exfoliation and flaking on candidate CTR first-wall materials, stainless steel and two types of inconels were bombarded by 0.8, 1 and 4 MeV helium ions. All the bombarded spots could be characterized by by large exfoliations covering almost the total implanted area. No spontaneous rupture was observed except on one type of inconel where flaking took place right after reaching the critical dose. After mechanical opening of the formations, similar inner morphology was found as in our previous studies on gold. (author)

  4. Surface Morphologies of Ti and Ti-Al-V Bombarded by 1.0-MeV Au+ Ions

    Science.gov (United States)

    Garcia, M. A.; Rickards, J.; Cuerno, R.; Trejo-Luna, R.; Cañetas-Ortega, J.; de la Vega, L. R.; Rodríguez-Fernández, L.

    2017-12-01

    Ion implantation is known to enhance the mechanical properties of biomaterials such as, e.g., the wear resistance of orthopedic joints. Increasing the surface area of implants may likewise improve their integration with, e.g., bone tissue, which requires surface features with sizes in the micron range. Ion implantation of biocompatible metals has recently been demonstrated to induce surface ripples with wavelengths of a few microns. However, the physical mechanisms controlling the formation and characteristics of these patterns are yet to be understood. We bombard Ti and Ti-6Al-4V surfaces with 1.0-MeV Au+ ions. Analysis by scanning electron and atomic force microscopies shows the formation of surface ripples with typical dimensions in the micron range, with potential indeed for biomedical applications. Under the present specific experimental conditions, the ripple properties are seen to strongly depend on the fluence of the implanted ions while being weakly dependent on the target material. Moreover, by examining experiments performed for incidence angle values θ =8 ° , 23°, 49°, and 67°, we confirm the existence of a threshold incidence angle for (ripple) pattern formation. Surface indentation is also used to study surface features under additional values of θ , agreeing with our single-angle experiments. All properties of the surface structuring process are very similar to those found in the production of surface nanopatterns under low-energy ion bombardment of semiconductor targets, in which the stopping power is dominated by nuclear contributions, as in our experiments. We consider a continuum model that combines the effects of various physical processes as originally developed in that context, with parameters that we estimate under a binary-collision approximation. Notably, reasonable agreement with our experimental observations is achieved, even under our high-energy conditions. Accordingly, in our system, ripple formation is determined by mass

  5. Surface temperature measurements for ion-bombarded Si and GaAs at 1.0 to 2.0 MeV

    International Nuclear Information System (INIS)

    Lowe, L.F.; Kennedy, J.K.; Davies, D.E.; Deane, M.L.; Eyges, L.J.

    1975-01-01

    Surface temperatures of ion-bombarded silicon and gallium arsenide have been measured using an infrared detector. Ion beams of N + , N + 2 , O + , O + 2 , C + , CO + , and H + were used at energies from 1--2.0 MeV and at current densities up to 12 μAcenter-dotcm/sup -2/. No temperature dependence was found on ion species, energy, or current. The change in temperature depended only on beam power, target material, and sample mounting technique. With proper mounting temperature increases of 20 degreeC for silicon and 65 degreeC for gallium arsenide were observed for a beam power density of 1.0 Wcenter-dotcm/sup -2/

  6. Ion emission in solids bombarded with Aun+ (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range

    International Nuclear Information System (INIS)

    Wehbe, Nimer

    2006-06-01

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry

  7. Surface roughening under ion bombardment

    International Nuclear Information System (INIS)

    Bhatia, C.S.

    1982-01-01

    Ion bombardment can cause roughening of a surface. Inadequate step coverage and poor adhesion of films on such surfaces are of concern. An extreme case of surface roughening results in cone formation under ion bombardment. The results of the investigation, using scanning electron microscopy, is discussed in terms of the role of (a) embedded particles, (b) impurities and (c) surface migration in cone formation on the target surface. (Auth.)

  8. Disordering and amorphization of Zr3Al by 3.8 MeV Zr3+ ion bombardment

    International Nuclear Information System (INIS)

    Chen, F.C.; Ardell, A.J.

    1991-01-01

    The ordered intermetallic compound Zr 3 Al was irradiated with 3. 8 MeV Zr 3+ ions at various fluences up to 5 x 10 12 tons/mm 2 at a temperature of 250 degrees C and the irradiation- induced microstructures were investigated by transmission electron microscopy. Disordering began at the lowest dose, 0.0033 dpa, and complete loss of chemical long-range order occurred at a dose of 0.33 dpa. The onset of amorphization was also observed at this dose. Electron diffraction patterns from irradiated samples showed satellite reflections along in thin foils in [100] orientation and streaking along in foils oriented [011]. These diffraction effects are attributed to the presence of irradiation-induced microstructural defects that, when imaged in dark field, resemble rows of dislocation loops. A model of these arrays of loops, which are suggested to have Burgers vectors of the Frank type, is proposed. The model accounts for the contrast effects observed in the images and the streaking and satellites seen in the diffraction patterns. At the highest dose, 1.6 dpa, a new phase, Zr 5 Al 3 , appeared unexpectedly, most likely as a consequence of irradiation-induced solute segregation

  9. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    An historical overview of the main advances in the understanding of bombardment-induced surface topography is presented. The implantation and sputtering mechanisms which are relevant to ion bombardment modification of surfaces and consequent structural, electronic and compositional changes are described. Descriptions of plasma and ion-beam sputtering-induced film formation, primary ion-beam deposition, dual beam techniques, cluster of molecule ion-beam deposition, and modification of thin film properties by ion bombardment during deposition are presented. A detailed account is given of the analytical and computational modelling of topography from the viewpoint of first erosion theory. Finally, an account of the possible application and/or importance of textured surfaces in technologies and/or experimental techniques not considered in previous chapters is presented. refs.; figs.; tabs

  10. Secondary ion emission from cleaned surfaces bombarded by 100 MeV accelerator beams at the GSI Darmstadt

    International Nuclear Information System (INIS)

    Wien, K.; Becker, O.; Guthier, W.; Knippelberg, W.; Koczon, P.

    1988-01-01

    The 1.4 MeV/n beam facility for the UNILAC/GSI has been used to study secondary ion emission from surfaces cleaned under UHV conditions by ion etching or cleaving of crystals. The desorption phenomena observed by means of TOF mass spectrometry can be classified as follows: (1) Clean metal surfaces emit metal ions being ejected by atomic collisions cascades. Electronic excitation of surface states seems to support ionization. (2) The desorption of contaminants adsorbed at the metal surface is strongly correlated with the electronic energy loss of the projectiles - even, if the content of impurities is very low. (3) Ion formation at the epitaxial surface of fluoride crystals as CaF 2 , MgF 2 and NaF is initiated by the electronic excitation of the crystal. At high beam energies the mass spectrum is dominated by a series of cluster ions. These cluster ions disappear below a certain energy deposit threshold, whereas small atomic ions are observed over the whole energy range

  11. Effects of MeV Si ions bombardment on the thermoelectric generator from SiO{sub 2}/SiO{sub 2} + Cu and SiO{sub 2}/SiO{sub 2} + Au nanolayered multilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Chacha, J., E-mail: chacha_john79@hotmail.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Smith, C., E-mail: cydale@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States); Pugh, M., E-mail: marcuspughp@yahoo.com [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Colon, T. [Department of Mechanical Engineering, Alabama A and M University, Normal, AL (United States); Heidary, K., E-mail: kaveh.heidary@aamu.edu [Department of Electrical Engineering, Alabama A and M University, Normal, AL (United States); Johnson, R.B., E-mail: barry@w4wb.com [Department of Physics, Alabama A and M University, Normal, AL (United States); Ila, D., E-mail: ila@cim.aamu.edu [Center for Irradiation of Materials, Alabama A and M University, Normal, AL (United States); Department of Physics, Alabama A and M University, Normal, AL (United States)

    2011-12-15

    The defects and disorder in the thin films caused by MeV ions bombardment and the grain boundaries of these nanoscale clusters increase phonon scattering and increase the chance of an inelastic interaction and phonon annihilation. We prepared the thermoelectric generator devices from 100 alternating layers of SiO{sub 2}/SiO{sub 2} + Cu multi-nano layered superlattice films at the total thickness of 382 nm and 50 alternating layers of SiO{sub 2}/SiO{sub 2} + Au multi-nano layered superlattice films at the total thickness of 147 nm using the physical vapor deposition (PVD). Rutherford Backscattering Spectrometry (RBS) and RUMP simulation have been used to determine the stoichiometry of the elements of SiO{sub 2}, Cu and Au in the multilayer films and the thickness of the grown multi-layer films. The 5 MeV Si ions bombardments have been performed using the AAMU-Center for Irradiation of Materials (CIM) Pelletron ion beam accelerator to make quantum (nano) dots and/or quantum (quantum) clusters in the multilayered superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity. To characterize the thermoelectric generator devices before and after Si ion bombardments we have measured Seebeck coefficient, cross-plane electrical conductivity, and thermal conductivity in the cross-plane geometry for different fluences.

  12. Ion bombardment modification of surfaces

    International Nuclear Information System (INIS)

    Auciello, O.

    1984-01-01

    Ion bombardment-induced modification of surfaces may be considered one of the significant scientific and technological developments of the last two decades. The understanding acquired concerning the underlying mechanisms of several phenomena occurring during ion-surface interactions has led to applications within different modern technologies. These include microelectronics, surface acoustical and optical technologies, solar energy conversion, thin film technology, ion implantation metallurgy, nuclear track technology, thermonuclear fusion, vacuum technology, cold welding technology, biomedicine (implantology). It has become clear that information on many relevant advances, regarding ion bombardment modification of surfaces is dispersed among journals involving fields sometimes not clearly related. This may result, in some cases, in a loss of the type of interdisciplinary exchange of ideas, which has proved to be so fruitful for the advancement of science and technology. This book has been planned in an attempt to collect at least some of today's relevant information about the experimental and theoretical knowledge related to surface modification and its application to technology. (Auth.)

  13. Characterization techniques for ion bombarded insulators

    International Nuclear Information System (INIS)

    Borders, J.A.

    1987-01-01

    The chapter gives a comprehensive review of the experimental methods for the analysis of ion-bombarded insulators including optical and structural methods, resonance, energetic ion methods, and surface techniques. 48 refs.; 34 figs

  14. Secondary ion emission from ultra-thin oxide layers bombarded by energetic (MeV) heavy ions: depth of origin and layer homogeneity

    International Nuclear Information System (INIS)

    Allali, H.; Nsouli, B.; Thomas, J.P.; Cabaud, B.; Fuchs, G.; Hoareau, A.; Treilleux, M.; Danel, J.S.

    1993-09-01

    The escape depth of the secondary ions resulting from electronic sputtering of fast heavy ions in inorganic thin films has been investigated. Chromium layers deposited onto SiO 2 substrate as well as SiO x layers deposited onto chromium substrate have been characterized by secondary ion emission mass spectrometry (SIMS) in combination with time-of-flight (TOF) mass analysis (also referred as HSF-SIMS). These crossed experiments lead to a value around 1 nm for SiO x layers and 0.5 nm for Cr layers. On the other hand, HSF-SIMS can be used to correlate the intensity of the secondary ion emission to the film coverage rate and (or) the morphology of particular films like those produced by Low Energy Cluster Beam Deposition (LECBD). Using Sb deposits, the non-linear relationship between ion emission and coverage is interpreted in terms of sputtering enhancement in the individual supported clusters. (author) 22 refs., 9 figs., 1 tab

  15. Anomalous microstructural changes in III-nitrides under ion bombardment

    International Nuclear Information System (INIS)

    Kucheyev, S.O.; Williams, J.S.; Jagadish, C.

    2002-01-01

    Full text: Group-III nitrides (GaN, AlGaN, and InGaN) are currently a 'hot topic' in the physics and material research community due to very important technological applications of these materials in (opto)electronics. In the fabrication of III-nitride-based devices, ion bombardment represents a very attractive processing tool. However, ion-beam-produced lattice disorder and its undesirable consequences limit technological applications of ion implantation. Hence, studies of ion-beam-damage processes in Ill-nitrides are not only physically interesting but also technologically important. In this study, wurtzite GaN, AlGaN, and InGaN films exposed to ion bombardment under a wide range of irradiation conditions are studied by a combination of transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy dispersive x-ray spectrometry (EDS), atomic force microscopy (AFM), cathodoluminescence (CL), and Rutherford backscattering/channeling (RBS/C) spectrometry. Results show that, unlike the situation for mature semiconductors such as Si and GaAs, Ill-nitrides exhibit a range of intriguing behavior involving extreme microstructural changes under ion bombardment. In this presentation, the following aspects are discussed: (i) formation of lattice defects during ion bombardment, (ii) ion-beam-induced phase transformations, (iii) ion-beam-produced stoichiometric imbalance and associated material decomposition, and (iv) an application of charging phenomena during ESEM imaging for studies of electrical isolation in GaN by MeV light ion irradiation. Emphasis is given to the (powerful) application of electron microscopy techniques for the understanding of physical processes occurring in Ill-nitrides under ion bombardment. Copyright (2002) Australian Society for Electron Microscopy Inc

  16. Ion bombardment and disorder in amorphous silicon

    International Nuclear Information System (INIS)

    Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

    1997-01-01

    The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects

  17. Compositional changes during ion bombardment

    International Nuclear Information System (INIS)

    Rehn, L.E.

    1988-09-01

    Ion irradiation initiates several processes that can alter the composition of the target. This presentation provides an overview of our current understanding of these kinetics processes, which include implantation, sputtering, displacement mixing, radiation-enhanced diffusion, and radiation-induced segregation. The latter two effects can alter the target composition to depths that are substantially greater than the projected ion range. 45 refs., 8 figs

  18. Magnetoresistance and ion bombardment induced magnetic patterning

    International Nuclear Information System (INIS)

    Hoeink, V.

    2008-01-01

    In this thesis the combination of the magnetic patterning of the unidirectional anisotropy and the tunnel magnetoresistance effect is investigated. In my diploma thesis, it has been shown that it is in principle possible to use the magnetic patterning by ion bombardment to magnetically structure the pinned layer in magnetic tunnel junctions (MTJs) with alumina barrier. Furthermore, it has been shown that the side effects which have been observed after this treatment can be at least reduced by an additional heating step. Starting from this point, the applicability of ion bombardment induced magnetic patterning (IBMP) in general and the combination of IBMP and MTJs in particular is investigated and new applications are developed. (orig.)

  19. Ion bombardment techniques - recent developments in SIMS

    International Nuclear Information System (INIS)

    Konarski, P.; Miśnik, M.

    2013-01-01

    We present a short review of cluster ion bombardment technique recently applied in SIMS. Many advantages of using cluster ion beams are specified over monoatomic ion species. Cluster ions open really new perspectives especially in organic based structures analysis. Nevertheless cluster ions are not the perfect solution and still new ideas of ion erosion in SIMS are needed. Another issue discussed is 'storing matter' technique applied for quantitative analysis in SIMS. Simple idea of sputter deposition of eroded material onto rotating substrate and then analysing the stored material allows to avoid strong matrix effects in SIMS. Presented are the results performed in Tele and Radio Research Institute, Warszawa, Poland. These are the first results of ‘storing matter’ technique performed in one analytical chamber of SIMS instrument. (authors)

  20. Electron emission from Inconel under ion bombardment

    International Nuclear Information System (INIS)

    Alonso, E.V.; Baragiola, R.A.; Ferron, J.; Oliva-Florio, A.

    1979-01-01

    Electron yields from clean and oxidized Inconel 625 surfaces have been measured for H + ,H 2 + ,He + ,O + and Ar + ions at normal incidence in the energy range 1.5 to 40 keV. These measurements have been made under ultrahigh vacuum and the samples were freed of surface contaminants by bombarding with high doses of either 20 keV H 2 + or 30 keV Ar + ions. Differences in yields of oxidized versus clean surfaces are explained in terms of differences in the probability that electrons internally excited escape upon reaching the surface. (author)

  1. Adhesion of silver films to ion-bombarded alumina

    International Nuclear Information System (INIS)

    Erck, R.A.; Fenske, G.R.

    1990-01-01

    This paper reports on silver films deposited on alumina substrates using ion bombardment. Adhesion strength was measured as a function of deposition conditions, sputter-cleaning time, and bombarding ion species, using a pull-type adhesion tester. Argon- and argon/oxygen-ion sputtering produced large increases in adhesion strength, with the greatest increases occurring for oxygen-ion bombardment. Adhesion strength increased monotonically as a function of ion sputtering time. At a given deposition rate, further enhancement of adhesion is seen with concurrent ion bombardment

  2. Study on evolution of gases from fluoropolymer films bombarded with heavy ions

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Zimmerman, Robert Lee; Budak, Satilmis; Ila, Daryush

    2008-01-01

    Ion beam bombardment provides a unique way of material modification by inducing a high degree of localized electronic excitation. The ion track, or affected volume along the ion path through the material is related to the total damage and possible structural changes. Here we study the evolution of gases emitted by poly(tetrafluorethylene-co-perfluoro-(propyl vinyl ether)) (PFA) fluoropolymer bombarded with MeV gold ions. The gas was monitored by a residual gas analyzer (RGA), as a function of the ion fluence. Micro-Raman, atomic force microscopy and optical absorption were used to analyze the chemical structure changes and sputtering yield

  3. Modification of thin film properties by ion bombardment during deposition

    International Nuclear Information System (INIS)

    Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

    1984-01-01

    Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. Examples of thin film property modification by ion bombardment during deposition, including effects which are primarily compositional as well as those which are primarily structural are presented. The examples demonstrate the usefulness of ion beam techniques in identifying and controlling the fundamental deposition parameters. 68 refs.; 15 figs.; 1 table

  4. Modification of thin film properties by ion bombardment during deposition

    International Nuclear Information System (INIS)

    Harper, J.M.E.; Cuomo, J.J.; Gambino, R.J.; Kaufman, H.R.

    1984-01-01

    Many thin film deposition techniques involve some form of energetic particle bombardment of the growing film. The degree of bombardment greatly influences the film composition, structure and other properties. While in some techniques the degree of bombardment is secondary to the original process design, in recent years more deposition systems are being designed with the capability for controlled ion bombardment of thin films during deposition. The highest degree of control is obtained with ion beam sources which operate independently of the vapor source providing the thin film material. Other plasma techniques offer varying degrees of control of energetic particle bombardment. Deposition methods involving ion bombardment are described, and the basic processes with which film properties are modified by ion bombardment are summarized. (Auth.)

  5. Cesium ion bombardment of metal surfaces

    International Nuclear Information System (INIS)

    Tompa, G.S.

    1986-01-01

    The steady state cesium coverage due to cesium ion bombardment of molybdenum and tungsten was studied for the incident energy range below 500 eV. When a sample is exposed to a positive ion beam, the work function decreases until steady state is reached with a total dose of less than ≅10 16 ions/cm 2 , for both tungsten and molybdenum. A steady state minimum work function surface is produced at an incident energy of ≅100 eV for molybdenum and at an incident energy of ≅45 eV for tungsten. Increasing the incident energy results in an increase in the work function corresponding to a decrease in the surface coverage of cesium. At incident energies less than that giving the minimum work function, the work function approaches that of cesium metal. At a given bombarding energy the cesium coverage of tungsten is uniformly less than that of molybdenum. Effects of hydrogen gas coadsorption were also examined. Hydrogen coadsorption does not have a large effect on the steady state work functions. The largest shifts in the work function due to the coadsorption of hydrogen occur on the samples when there is no cesium present. A theory describing the steady-state coverage was developed is used to make predictions for other materials. A simple sticking and sputtering relationship, not including implantation, cannot account for the steady state coverage. At low concentrations, cesium coverage of a target is proportional to the ratio of (1 - β)/γ where β is the reflection coefficient and γ is the sputter yield. High coverages are produced on molybdenum due to implantation and low backscattering, because molybdenum is lighter than cesium. For tungsten the high backscattering and low implantation result in low coverages

  6. Cleaning of diffusion bonding surface by argon ion bombardment treatment

    International Nuclear Information System (INIS)

    Wang, Airu; Ohashi, Osamu; Yamaguchi, Norio; Aoki, Masanori; Higashi, Yasuo; Hitomi, Nobuteru

    2003-01-01

    The specimens of oxygen-free high conductivity copper, SUS304L stainless steel and pure iron were treated by argon ion bombardment and then were bonded by diffusion bonding method. The effects of argon ion bombardment treatment on faying surface morphology, tensile strength of bonding joints and inclusions at the fracture surface were investigated. The results showed that argon ion bombardment treatment was effective to remove the oxide film and contamination at the faying surface and improve the quality of joints. The tensile strength of the bonded joints was improved, and minimum bonding temperature to make the metallic bonding at the interface was lowered by argon ion bombardment treatment. At the joints with argon ion bombardment treatment, ductile fractured surface was seen and the amount of inclusions was obviously decreased

  7. Effects of low and high energy ion bombardment on ETFE polymer

    Science.gov (United States)

    Minamisawa, R. A.; De Almeida, A.; Abidzina, V.; Parada, M. A.; Muntele, I.; Ila, D.

    2007-04-01

    The polymer ethylenetetrafluoroethylene (ETFE) is used as anti-adherent coatings for food packages and radiation dosimeters. In this work, we compare the damage induced in ETFE bombarded with 100 keV Si ions with that induced by 1 MeV proton bombardment. The damage depends on the type, energy and intensity of the irradiation. Irradiated films were analyzed with optical absorption photospectrometry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy to determine the chemical nature of the structural changes caused by ion irradiation. Computer simulations were performed to evaluate the radiation damage.

  8. Modification of Polymer Materials by Ion Bombardment: Case Studies

    International Nuclear Information System (INIS)

    Bielinski, D. M.; Jagielski, J.; Lipinski, P.; Pieczynska, D.; Ostaszewska, U.; Piatkowska, A.

    2009-01-01

    The paper discusses possibility of application of ion beam bombardment for modification of polymers. Changes to composition, structure and morphology of the surface layer produced by the treatment and their influence on engineering and functional properties of wide range of polymer materials are presented. Special attention has been devoted to modification of tribological properties. Ion bombardment results in significant reduction of friction, which can be explained by increase of hardness and wettability of polymer materials. Hard but thin enough skin does not result in cracking but improves their abrasion resistance. Contrary to conventional chemical treatment ion beam bombardment works even for polymers hardly susceptible to modification like silicone rubber or polyolefines.

  9. Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

    International Nuclear Information System (INIS)

    Sone, Kazuho; Shiraishi, Kensuke

    1975-04-01

    The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage. (auth.)

  10. Calculations on displacement damage and its related parameters for heavy ion bombardment in reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Sone, K; Shiraishi, K

    1975-04-01

    The depth distribution of displacement damage expressed in displacements per atom (DPA) in reactor materials such as Mo, Nb, V, Fe and Ni bombarded by energetic nitrogen, argon and self ions with incident energy below 2 MeV was calculated following the theory developed by Lindhard and co-workers for the partition of energy as an energetic ion slowing down. In this calculation, energy loss due to electron excitation was taken into account for the atomic collision cascade after the primary knock-on process. Some parameters indispensable for the calculation such as energy loss rate, damage efficiency, projected range and its straggling were tabulated as a function of incident ion energy of 20 keV to 2 MeV. The damage and parameters were also calculated for 2 MeV nickel ions bombarding Fe targets. In this case, the DPA value is of 40--75% overestimated in a calculation disregarding electronic energy loss for primary knock-on atoms. The formula proposed in this report is significant for calculations on displacement damage produced by heavy ion bombardment as a simulation of high fluence fast neutron damage.

  11. Computer simulation of the topography evolution on ion bombarded surfaces

    CERN Document Server

    Zier, M

    2003-01-01

    The development of roughness on ion bombarded surfaces (facets, ripples) on single crystalline and amorphous homogeneous solids plays an important role for example in depth profiling techniques. To verify a faceting mechanism based not only on sputtering by directly impinging ions but also on the contribution of reflected ions and the redeposition of sputtered material a computer simulation has been carried out. The surface in this model is treated as a two-dimensional line segment profile. The model describes the topography evolution on ion bombarded surfaces including the growth mechanism of a facetted surface, using only the interplay of reflected and primary ions and redeposited atoms.

  12. Adhesion of evaporated titanium films to ion-bombarded polyethylene

    International Nuclear Information System (INIS)

    Bodoe, P.; Sundgren, J.

    1986-01-01

    Ti films were deposited onto high-density polyethylene (HDPE) samples by electron-beam evaporation. Prior to film deposition the samples were in situ pretreated by Ar ion bombardment using a sputter ion gun. The adhesion of the films, determined as the pull strength required for film failure, was measured as a function of ion dose. HDPE substrates processed at two different temperatures were examined. The adhesion of the Ti films to HDPE samples processed at roughly-equal150 0 C increased with the ion dose to a steady-state value corresponding to the cohesive strength of the HDPE substrate. The adhesion to the samples processed at roughly-equal200 0 C increased to a maximum and then decreased for further ion bombardment to a level of the same order as that for films deposited onto as-prepared samples. The effects of the ion bombardment upon the HDPE surface chemistry were examined by means of x-ray photoelectron spectroscopy (XPS). The ion bombardment resulted in dehydrogenation and cross linking of the surface region and for prolonged ion bombardment, a graphitelike surface was obtained. The film/substrate interface as well as the initial Ti film growth were examined by XPS analysis. A chemical interaction which resulted in Ti--C bonds was observed at the interface. The Ti film growth followed a pronounced three-dimensional growth mode on as-prepared surfaces whereas the ion bombardment resulted in a change toward a more two-dimensional growth mode. The difference in adhesion behavior for the two types of HDPE substrates was found to be due to a difference in the amounts of low molecular weight products present within the substrates

  13. Considerations about projectile and target X-rays induced during heavy ion bombardment

    Science.gov (United States)

    Fernandes, F.; Bauer, D. V.; Duarte, A.; Ferrari, T. M.; Niekraszewicz, L. A. B.; Amaral, L.; Dias, J. F.

    2018-02-01

    In this work we present some results concerning the X-rays emitted by heavy ions during target bombardment. In this case, Cl4+ and Cl5+ ions with energies from 4 MeV to 10 MeV were employed to irradiate vitreous carbon planchets. Moreover, total X-ray production cross sections of titanium X-rays induced by chlorine ions were obtained as well for the same energy range. Only inner shell transitions were considered in the present work. The titanium target consisted of a thin film deposited over vitreous carbon planchets. The results indicate that the projectile X-ray yields increase as a function of the bombarding energy for the present energy range. Effects due to projectile charge state appears to be of minor importance at these low ion velocities. It is shown that a simple exponential function can represent the continuum background of such complex spectra. The chlorine transition rates Kβ/Kα obtained from chlorine acting as a projectile interacting with a carbon target are about half the value when compared to the chlorine Kβ/Kα ratios obtained when a LiCl target is bombarded with C+ and C3+ ions with energies from 2 MeV to 6 MeV. As far as the total X-ray production cross sections of Ti induced by chlorine ions are concerned, the ECPSSR theory underestimates the Ti total X-rays production cross sections by several orders of magnitude. The role of electron capture and possible mechanisms responsible for these effects are discussed.

  14. Catalytic oxidation of silicon by cesium ion bombardment

    International Nuclear Information System (INIS)

    Souzis, A.E.; Huang, H.; Carr, W.E.; Seidl, M.

    1991-01-01

    Results for room-temperature oxidation of silicon using cesium ion bombardment and low oxygen exposure are presented. Bombardment with cesium ions is shown to allow oxidation at O 2 pressures orders of magnitude smaller than with noble gas ion bombardment. Oxide layers of up to 30 A in thickness are grown with beam energies ranging from 20--2000 eV, O 2 pressures from 10 -9 to 10 -6 Torr, and total O 2 exposures of 10 0 to 10 4 L. Results are shown to be consistent with models indicating that initial oxidation of silicon is via dissociative chemisorption of O 2 , and that the low work function of the cesium- and oxygen-coated silicon plays the primary role in promoting the oxidation process

  15. Ion bombardment induced ripple topography on amorphous solids

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Paton, F.; Williams, J.S.

    1977-01-01

    Earlier studies of the ion bombardment induced ripple morphology on the surfaces of amorphous solids when compared with geomorphological effects are shown to possess many similar features. The present study, with 40 keV Ar + ion bombarded Si suggests that analogies are incomplete, however, and that greater similarities with the process of macroscopic sandblasting (corrosion) exist. It is shown that the genesis of wave like structures on Si is from isolated features, which have the appearance of ripple trains, which are faceted. It is suggested that these features result from particle flux enhancement processes near surface dimples generated by stress induced surface lifting. (author)

  16. Ion emission in solids bombarded with Au{sub n}{sup +} (n = 1 - 9) clusters accelerated within the 0.15 - 1.25 MeV energy range; Emission ionique des solides a l'impact d'agregats Au{sub n}{sup +} (n=1-9) acceleres entre 0,15 et 1,25 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Wehbe, Nimer [Universite Claude Bernard Lyon-I, 43 boulevard du 11 Novembre 1918, 69622 Villeurbanne cedex (France)

    2006-06-15

    This experimental work is devoted to the study of the ion emission in solids at the impact of gold clusters of energies within 0.15 to 1.25 MeV range. The physics of ion-solid collisions and the theoretical models of sputtering of solids under ion bombardment are presented in the first chapter. The chapter no. 2 deals with the description of the experimental setup. The study of a gold target allowed to evidence the role of the size and energy of the clusters in determining the emission intensity and the mass distribution of the ions. The 4. chapter gives results from the study of cesium iodide in which the intense emission of CsI clusters could be investigated quantitatively due to multiplicity measurements. Finally, the chapter no. 5 was devoted to the study of a biologic molecule, the phenylalanine, and of a pesticide molecule, chlorosulfuron. This work evidenced the importance of clusters for surface analyses by mass spectrometry.

  17. Electron emission from molybdenum under ion bombardment

    International Nuclear Information System (INIS)

    Ferron, J.; Alonso, E.V.; Baragiola, R.A.; Oliva-Florio, A.

    1981-01-01

    Measurements are reported of electron emission yields of clean molybdenum surfaces under bombardment with H + , H 2 + , D + , D 2 + , He + , N + , N 2 + , O + , O 2 + , Ne + , Ar + , Kr + and Xe + in the wide energy range 0.7-60.2 keV. The clean surfaces were produced by inert gas sputtering under ultrahigh vacuum. The results are compared with those predicted by a core-level excitation model. The disagreement found when using correct values for the energy levels of Mo is traced to wrong assumptions in the model. A substantially improved agreement with experiment is obtained using a model in which electron emission results from the excitation of valence electrons from the target by the projectiles and fast recoiling target atoms. (author)

  18. Ion bombardment effect on surface state of metal

    International Nuclear Information System (INIS)

    Vaulin, E.P.; Georgieva, N.E.; Martynenko, T.P.

    1990-01-01

    The effect of slow argon ion bombardment on the surface microstructure of polycrystalline copper as well as the effect of surface state on sputtering of D-16 polycrystalline alloy are experimentally studied. Reduction of copper surface roughness is observed. It is shown that the D-16 alloy sputtering coefficient is sensitive to the surface state within the limits of the destructed surface layer

  19. Ion bombardment simulation: a review related to fusion radiation damage

    International Nuclear Information System (INIS)

    Brimhall, J.L.

    1975-01-01

    Prime emphasis is given to reviewing the ion bombardment data on the refractory metals molybdenum, niobium and vanadium which have been proposed for use in advanced fusion devices. The temperature and dose dependence of the void parameters are correlated among these metals. The effect of helium and hydrogen gas on the void parameters is also included. The similarities and differences of the response of these materials to high dose, high temperature radiation damage are evaluated. Comparisons are made with results obtained from stainless steel and nickel base alloys. The ion bombardment data is then compared and correlated, as far as possible, with existing neutron data on the refractory metals. The theoretically calculated damage state produced by neutrons and ions is also briefly discussed and compared to experimental data wherever possible. The advantages and limitations of ion simulation in relation to fusion radiation damage are finally summarized

  20. Destruction of C60 films by boron ion bombardment

    International Nuclear Information System (INIS)

    Ren Zhongmin; Du Yuancheng; Ying Zhifeng; Xiong Xiaxing; Li Fuming

    1995-01-01

    C 60 films are bombarded by 100 keV boron ion beams at doses ranging from 3x10 14 to 1x10 16 /cm 2 . The bombarded films are analyzed using Fourier transform infrared spectroscopy (FTIR), Raman spectra and X-ray diffraction (XRD) measurements. Most C 60 soccer-balls in the implanted region in the films are found to be broken at a dose over 1x10 15 /cm 2 , while at a dose less than 6x10 14 /cm 2 a few C 60 molecules remain undestroyed and maintain some crystal structure. The results of the analyses suggest a complete disintegration of a C 60 molecule under B + bombardment. ((orig.))

  1. Ion bombardment damage in a modified Fe-9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Farrell, K.; Lee, E.H.

    1984-01-01

    A normalized-and-tempered Fe-9Cr-1Mo steel, with small Nb and V additions, was bombarded with 4-MeV iron ions to 100 dpa at 400, 450, 500, 550, and 600 0 C. Major damage feature was dislocation tangles which coarsened with increasing bombardment temperature. Sparse cavities were heterogeneously distributed at 500 and 550 0 C. Incorporation of helium and deuterium simultaneously in the bombardments at rates of 10 and 45 appM/dpa, respectively, introduced very high concentrations of small cavities at all temperatures, many of them on grain boundaries. These cavities were shown to be promoted by helium. A small fraction of the matrix cavities exhibited bias-driven growth at 500 and 550 0 C, with swelling 0 C higher than the peak swelling temperature found in neutron irradiations, which is compatible with the higher damage rate used in the ion bombardments. High concentrations of subgrain boundaries and dislocations resulting from the heat treatment, and unbalanced cavity and dislocation sink strengths in the damage structures contribute to the swelling resistance. Such resistance may not be permanent. High densities of bubbles on grain boundaries indicate a need for helium embrittlement tests

  2. Development of pits and cones on ion bombarded copper

    International Nuclear Information System (INIS)

    Tanovic, L.A.; Carter, G.; Nobes, M.J.; Whitton, I.L.; Williams, J.S.

    1980-01-01

    The formation of pits and cones on Ar ion bombarded copper has been studied. Carefully polished surfaces of large grained 99.999% pure copper crystals have been bombarded at normal incidence with 40 keV argon ions. The cone formation has been investigated for annealed and non-annealed crystals at room temperature and at 30 K and in the case of monocrystal and polycrystal samples. Although in the most other studies the presence of impurities is as a necessary condition for generation of cones and pits the obtained experimental results show that under certain conditions these features are formed on clean surfaces. It is shown that the dominant parameter in the production of cones on copper is the crystal orientation [ru

  3. Thermo-mechanical design aspects of mercury bombardment ion thrusters.

    Science.gov (United States)

    Schnelker, D. E.; Kami, S.

    1972-01-01

    The mechanical design criteria are presented as background considerations for solving problems associated with the thermomechanical design of mercury ion bombardment thrusters. Various analytical procedures are used to aid in the development of thruster subassemblies and components in the fields of heat transfer, vibration, and stress analysis. Examples of these techniques which provide computer solutions to predict and control stress levels encountered during launch and operation of thruster systems are discussed. Computer models of specific examples are presented.

  4. Emission of positive oxygen ions from ion bombardment of adsorbate-covered metal surfaces

    International Nuclear Information System (INIS)

    Kaurin, M.G.

    1989-01-01

    During ion bombardment of metal surfaces, collision cascades can result in the emission of sputtered secondary ions. Recent experiments, however, have suggested that the emission of positive ions of electronegative adsorbates can result from electronic processes rather than from processes involving elastic collisions. This dissertation presents the results of experiments studying the emission of positive oxygen ions from oxygen- and carbon-monoxide-covered transition metal surfaces during bombardment by 25-250 keV ions of neon, argon, and krypton. The systems studied may be grouped into four categories. For a nickel substrate with adsorbed oxygen, the emission of positive oxygen ions proceeds through collision cascades. For titanium and niobium with adsorbed oxygen, the emission of positive oxygen ions is proportional to the primary ion velocity, consistent with emission from electronic processes; for a given primary ion velocity, the oxygen ion yield is independent of primary ion species. For substrates of molybdenum and tungsten, the oxygen yield is proportional to primary ion velocity, but the yield also depends on the primary ion species for a given primary ion velocity in a manner that is consistent with emission resulting from electronic processes. For these two groups, except for titanium, the yields during neon ion bombardment do not extrapolate (assuming linearity with primary ion velocity) to a nonzero value at zero beam velocity. The magnitude of the oxygen ion yields from these targets is not consistent with that expected if the emission were induced by secondary electrons emitted during the ion bombardment

  5. Study of associated gamma from niobium under 14. 9 MeV neutron bombardments

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Hongyu; Yan Yiming; Fan Guoying; Lan Liqiac; Sun Suxu; Wang Qi; Hua Ming; Han Chongzhen; Liu Shuzhenn; Rong Yaning; and others

    1989-02-01

    The gamma ray spectra from niobium under 14.9 MeV neutron bombardments were measured by means of a pulsed /ital T/(/ital d/, /ital n/)/sup 4/He neutron source, associated particle method, Ge(Li) detector and time-of-flight technique at 7 angles between 30/degree/ and 140/degree/. 79 gamma lines were determined by a high resolution gamma spectrum analysis program, and reaction types and transition levels of 62 lines were roughly assigned. There were 40 ones of 79 lines, which were first found in reactions induced by neutrons. The differential cross sections of every gamma line at 7 angles were determined. It is shown that associated gamma ray emissions from this reaction are basically isotropic.

  6. Direct evidence for a thermal effect of Ar+ ion bombardment in a conventional sputtering mode

    International Nuclear Information System (INIS)

    Okuyama, F.; Fujimoto, Y.

    1986-01-01

    Evidence is presented that the Ar + ion bombardment for sputtering in Auger electron spectroscopy can heat the target up to 2000 0 C if the target has poor heat conduction. Polycrystalline microneedles of Cr exhibited spherical tips after being exposed to 3 keV Ar + ions, proving that the needle tips were melted by impacting Ar + ions. Microneedles of Mo ion bombarded under the same condition were bent plastically, which perhaps reflects the thermal annealing of the needles during ion bombardment

  7. Surface damage studies of ETFE polymer bombarded with low energy Si ions (≤100 keV)

    International Nuclear Information System (INIS)

    Minamisawa, Renato Amaral; Almeida, Adelaide De; Budak, Satilmis; Abidzina, Volha; Ila, Daryush

    2007-01-01

    Surface studies of ethylenetetrafluoroethylene (ETFE), bombarded with Si in a high-energy tandem Pelletron accelerator, have recently been reported. Si ion bombardment with a few MeV to a few hundred keV energies was shown to be sufficient to produce damage on ETFE film. We report here the use of a low energy implanter with Si ion energies lower than 100 keV, to induce changes on ETFE films. In order to determine the radiation damage, ETFE bombarded films were simulated with SRIM software and analyzed with optical absorption photometry (OAP), Raman and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to show quantitatively the physical and chemical property changes. Carbonization occurs following higher dose implantation, and hydroperoxides were formed following dehydroflorination of the polymer

  8. Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@thep-center.org [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2014-05-01

    Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms.

  9. Ultra-low-energy (<10 eV/u) ion beam bombardment effect on naked DNA

    International Nuclear Information System (INIS)

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

    2014-01-01

    Highlights: • Decelerated ultra-low energy ion beam bombarded naked DNA. • DNA form change induced by ion bombardment was investigated. • N-ion bombardment at 32 eV induced DNA single and double strand breaks. • Ar-ion bombardment at a-few-hundreds eV induced DNA single strand break. - Abstract: Since ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range, it is very interesting to know effects from ultra-low-energy ion interaction with DNA for understanding ion-beam-induced genetic mutation. Tens-keV Ar- and N-ion beams were decelerated to ultra-low energy ranging from 20 to 100 eV, or only a few to 10 eV/u, to bombard naked plasmid DNA. The bombarded DNA was analyzed using gel electrophoresis for DNA form changes. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks after bombarded by tens-eV ion beam. N-ion beam was found more effective in inducing DNA change and mutation than Ar-ion beam. The study demonstrated that the ion bombardment with energy as low as several-tens eV was able to break DNA strands and thus potentially to cause genetic modification of biological cells. The experimental results were discussed in terms of direct atomic collision between the ions and DNA atoms

  10. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    Energy Technology Data Exchange (ETDEWEB)

    Thopan, P.; Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Suwannakachorn, D. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuldyuld@gmail.com [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells.

  11. An ion beam deceleration lens for ultra-low-energy ion bombardment of naked DNA

    International Nuclear Information System (INIS)

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

    2013-01-01

    Highlights: ► An ion beam deceleration lens was designed and constructed. ► The deceleration lens was installed and tested. ► The decelerated ion beam energy was measured using an electrical field. ► Decelerated ultra-low-energy ion beam bombarded naked DNA. ► Ion beam with energy of a few tens of eV could break DNA strands. -- Abstract: Study of low-energy ion bombardment effect on biological living materials is of significance. High-energy ion beam irradiation of biological materials such as organs and cells has no doubt biological effects. However, ion energy deposition in the ion-bombarded materials dominantly occurs in the low-energy range. To investigate effects from very-low-energy ion bombardment on biological materials, an ion beam deceleration lens is necessary for uniform ion energy lower than keV. A deceleration lens was designed and constructed based on study of the beam optics using the SIMION program. The lens consisted of six electrodes, able to focus and decelerate primary ion beam, with the last one being a long tube to obtain a parallel uniform exiting beam. The deceleration lens was installed to our 30-kV bioengineering-specialized ion beam line. The final decelerated-ion energy was measured using a simple electrostatic field to bend the beam to range from 10 eV to 1 keV controlled by the lens parameters and the primary beam condition. In a preliminary test, nitrogen ion beam at 60 eV decelerated from a primary 20-keV beam bombarded naked plasmid DNA. The original DNA supercoiled form was found to change to relaxed and linear forms, indicating single or double strand breaks. The study demonstrated that the ion bombardment with energy as low as several-tens eV was possible to break DNA strands and thus potential to cause genetic modification of biological cells

  12. Model to estimate fractal dimension for ion-bombarded materials

    Energy Technology Data Exchange (ETDEWEB)

    Hu, A., E-mail: hu77@purdue.edu; Hassanein, A.

    2014-03-15

    Comprehensive fractal Monte Carlo model ITMC-F (Hu and Hassanein, 2012 [1]) is developed based on the Monte Carlo ion bombardment simulation code, i.e., Ion Transport in Materials and Compounds (ITMC) code (Hassanein, 1985 [2]). The ITMC-F studies the impact of surface roughness on the angular dependence of sputtering yield. Instead of assuming material surfaces to be flat or composed of exact self-similar fractals in simulation, we developed a new method to describe the surface shapes. Random fractal surfaces which are generated by midpoint displacement algorithm and support vector machine algorithm are combined with ITMC. With this new fractal version of ITMC-F, we successfully simulated the angular dependence of sputtering yield for various ion-target combinations, with the input surface roughness exponent directly depicted from experimental data (Hu and Hassanein, 2012 [1]). The ITMC-F code showed good agreement with the experimental data. In advanced, we compare other experimental sputtering yield with the results from ITMC-F to estimate the surface roughness exponent for ion-bombarded material in this research.

  13. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Energy Technology Data Exchange (ETDEWEB)

    Semsang, Nuananong, E-mail: nsemsang@gmail.com [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, LiangDeng [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: ► Ion beam bombarded rice seeds in vacuum. ► Studied seed survival from the ion bombardment. ► Determined various antioxidant enzyme activities and lipid peroxidation level. ► Discussed vacuum, ion species and ion energy effects. ► Attributed the changes to free radical formation due to ion bombardment. -- Abstract: Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29–60 keV and ion fluences of 1 × 10{sup 16} ions cm{sup −2}. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  14. MeV ion induced damage production and accumulation in silicon

    International Nuclear Information System (INIS)

    Suzuki, Motoyuki; Okazaki, Makoto; Shin, Kazuo; Takagi, Ikuji; Yoshida, Koji

    1993-01-01

    Measurement and analysis were made for radiation damages in silicon induced by MeV ions. A single crystal silicon was bombarded by 800 keV O + and 700 keV Si + with the dose from 2x10 15 up to 8x10 15 cm -2 . And defects induced by the ion bombardments were observed by the channeling method. Some new modifications were made to the analysis of the channeling RBS spectrum so that the accuracy of the unfolded defect distribution may be improved. A new model of point-defect clustering and amorphous formation was proposed, which well reproduced the observed defect distribution in silicon. (author)

  15. Induction of antioxidant enzyme activity and lipid peroxidation level in ion-beam-bombarded rice seeds

    Science.gov (United States)

    Semsang, Nuananong; Yu, LiangDeng

    2013-07-01

    Low-energy ion beam bombardment has been used to mutate a wide variety of plant species. To explore the indirect effects of low-energy ion beam on biological damage due to the free radical production in plant cells, the increase in antioxidant enzyme activities and lipid peroxidation level was investigated in ion-bombarded rice seeds. Local rice seeds were bombarded with nitrogen or argon ion beams at energies of 29-60 keV and ion fluences of 1 × 1016 ions cm-2. The activities of the antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST) and lipid peroxidation level were assayed in the germinated rice seeds after ion bombardment. The results showed most of the enzyme activities and lipid peroxidation levels in both the argon and nitrogen bombarded samples were higher than those in the natural control. N-ion bombardment could induce higher levels of antioxidant enzyme activities in the rice samples than the Ar-ion bombardment. Additional effects due to the vacuum condition were found to affect activities of some antioxidant enzymes and lipid peroxidation level. This study demonstrates that ion beam bombardment and vacuum condition could induce the antioxidant enzyme activity and lipid peroxidation level which might be due to free radical production in the bombarded rice seeds.

  16. Continuum radiation emitted from transition metals under ion bombardment

    International Nuclear Information System (INIS)

    El Boujlaidi, A.; Kaddouri, A.; Ait El Fqih, M.; Hammoum, K.; Aouchiche, H.

    2012-01-01

    Optical emission of transition metals has been studied during 5 keV Kr + ions bombardment within and without oxygen atmosphere in the colliding chamber. The observed spectra consist of a series of discrete lines superimposed on a broad continuum. Generally, the emission intensity was influenced by the presence of oxygen giving rise to transient effects as well as to an increase in the line intensity. The behaviours of spectral lines were successfully explained in term of electron-transfer process between the excited sputtered atom and the solid surface. In this work, we have focused our study on the continuous radiation emitted during ion bombardment. The experimental results suggest that the continuum emission depends on the nature of metal and very probably related to its electronic structure. The collective deactivation of 3d-shell electrons appears to play a role in the emission of this radiation. The observed enhancement in the presence of oxygen is probably due to a significant contribution of the oxide molecules. (authors)

  17. Light ions cyclotron bombardment to simulate fast neutron radiation damage in nuclear materials

    International Nuclear Information System (INIS)

    Segura, E.; Lucki, G.; Aguiar, D.

    1984-01-01

    The applicability and limitations of the use of cyclotron light ions bombardment to simulate the effects of the neutron irradiation are presented. Light ions with energies of about 10 MeV are capable to produce homogeneous damage in specimens suitable for measuring bulk mechanical properties although their low damage rate of 10 -5 dpa.sec -1 limit the dose range to a few dpa. On the other hand, cyclotron alpha particle implantation provides a fast and convenient way of introducing helium with a minimum of side effects so that we can take advantage of this technique to get better understanding of the mechanism by which this insoluble gas produces high temperature embrittlement. Some experimental details such as dimensions and cooling techniques are described. Finally a description of the infrastructure for cyclotron alpha particle implantation and a creep-test facility of the Division of Radiation Damage at IPEN-CNEN/SP are presented. (Author) [pt

  18. Facies of ion bombarded surfaces of brittle materials

    International Nuclear Information System (INIS)

    Primak, W.

    1975-12-01

    Materials were bombarded by protons, deuterons, and helium ions. The materials investigated were quartz; glasses; carbides and borides (SiC, B 4 C, TiB 2 ); oxides and nitrides (magnorite, sapphire, spinel, Al 2 O 3 , Si 3 N 4 , ZrO 2 , BaTiO 3 ); and miscellaneous (graphite, LiNbO 3 , copper). Oberservations were of growth, reflectivity, blistering, surface ablation, and swelling. Calculations were made of the effects of a layer, of its gradual transformation, and of the introduction of a gas. It is concluded that: Radiation blistering is not a primary process. Observations of blister formation and exfoliation cannot be used to calculate the surface ablation rate. The primary process is the development of a microporous layer which causes swelling. Visible blisters are caused by fracturing by transverse stresses in this layer and may occur during the bombardment, or in some cases, much later, in storage. There is no evidence of extreme gas pressures in the blisters. When blisters develop, they may be stable under continued bombardment for a dose many times that at which they formed. The swelling is a better index of the effects than is the blistering, and must be associated in most cases with permeability to the gas. Behavior with protons and deuterons is similar, with helium different. All but quartz, vitreous silica, and Pyrex are impervious to hydrogen and deuterium; only dense barium crown glass, carbides, borides, oxides, and nitrides are impervious to helium. Quartz shows swelling caused by conversion to a vitreous product of much lower density but no porosity, while for the others, most of the swelling and surface growth is caused by porosity. Surface ablation by the blistering process may be reduced by initial porosity or by initial or subsequent surface fissuring. However, for impervious materials, surface damage by the introduction of porosity would continue

  19. Experiments on secondary ion emission with multicharged keV ion bombardement

    International Nuclear Information System (INIS)

    Della Negra, S.; Depauw, J.; Joret, H.; Le Beyec, Y.; Schweikert, E.A.

    1987-01-01

    An electron cyclotron resonance ion source was used to study the influence of the incident charge state of keV ions on secondary ion emission. The experiments were run with 18 keV Arn+ (1 < n < 11) beams produced by a minimafios source. Various types of targets were bombarded by the ion beam and the sputtered ionized species were identified by time of flight mass spectrometry. The experimental arrangement is detailed and preliminary results are indicated

  20. Chemical changes in titanate surfaces induced by Ar+ ion bombardment

    International Nuclear Information System (INIS)

    Gonzalez-Elipe, A.R.; Fernandez, A.; Espinos, J.P.; Munuera, G.; Sanz, J.M.

    1992-01-01

    The reduction effects and compositional changes induced by 3.5 keV Ar + bombardment of several titanates (i.e. SrTiO 3 , Al 2 TiO 5 and NiTiO 3 ) have been quantitatively investigated by XPS. In all the samples studied here the original Ti 4+ species were reduced to lower oxidation states (i.e. Ti 3+ and Ti 2+ ), although to a lesser extent than in pure TiO 2 . On the contrary, whereas Sr 2+ and Al 3+ seem to remain unaffected by Ar + bombardment, in agreement with the behaviour of the respective oxides (i.e. SrO and Al 2 O 3 ), Ni 2+ appears more easily reducible to Ni o in NiTiO 3 than in NiO. In addition, other specific differences were observed between the titanates, which reveal the existence of interesting chemical effects related to the presence of the different counter-ions in the titanates. In the case of Al 2 TiO 5 , its Ar + -induced decomposition to form TiO 2 + Al 2 O 3 could be followed by XPS. (Author)

  1. Ion bombardment effects on surface states in selected oxide systems: rutile and alkaline earth titanates

    International Nuclear Information System (INIS)

    Gruen, D.M.

    1978-01-01

    In this paper, the nature of the surface states of n-type TiO 2 and SrTiO 3 is discussed and the role of ion bombardment in modifying the properties of these states is elucidated. Insofar as possible, the interrelationships between oxide nonstoichiometry, surface states, ion bombardment effects and photoelectrolysis are explored

  2. Annealing of defects in indium antimonide after ion bombardment

    International Nuclear Information System (INIS)

    Bogatyrev, V.A.; Kachurin, G.A.

    1977-01-01

    Indium antimonide electric properties are investigated after ion bombardment of different mass (with energy of 60 and 300 keV) and isochrone annealing in the 20-450 deg C temperature range. It is shown that 100-150 deg C n- type stable layers are formed after proton irradiation at room temperature only. Indium antimonide exposure by average mass ions under the same conditions and also by helium ions of 300 keV energy brings to p-type layer formation with high hole concentration. Subsequent heating at the temperature over 150 deg C results in electron conductivity of irradiated layers. Electron volume density and mobility efficiency reaches 10 18 cm -3 and 10 4 cm 2 /Vs respectively. N-type formed layers are stable up to 350 deg C allowing its usage for n-p transition formation admitting thermal treatment. Analysis is given of defect behaviour peculiarities depending upon the irradiation and annealing conditions. Hole conductivity in irradiated indium antimonide is supposed to be stipulated by regions of disorder, while electron conductivity - by relatively simpler disorders

  3. Particle-In-Cell/Monte Carlo Simulation of Ion Back Bombardment in Photoinjectors

    International Nuclear Information System (INIS)

    Qiang, Ji; Corlett, John; Staples, John

    2009-01-01

    In this paper, we report on studies of ion back bombardment in high average current dc and rf photoinjectors using a particle-in-cell/Monte Carlo method. Using H 2 ion as an example, we observed that the ion density and energy deposition on the photocathode in rf guns are order of magnitude lower than that in a dc gun. A higher rf frequency helps mitigate the ion back bombardment of the cathode in rf guns

  4. Systematic analysis of neutron yields from thick targets bombarded by heavy ions and protons with moving source model

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Takashi; Kurosawa, Tadahiro; Nakamura, Takashi E-mail: nakamura@cyric.tohoku.ac.jp

    2002-03-21

    A simple phenomenological analysis using the moving source model has been performed on the neutron energy spectra produced by bombarding thick targets with high energy heavy ions which have been systematically measured at the Heavy-Ion Medical Accelerator (HIMAC) facility (located in Chiba, Japan) of the National Institute of Radiological Sciences (NIRS). For the bombardment of both heavy ions and protons in the energy region of 100-500 MeV per nucleon, the moving source model incorporating the knock-on process could be generally successful in reproducing the measured neutron spectra within a factor of two margin of accuracy. This phenomenological analytical equation is expressed having several parameters as functions of atomic number Z{sub p}, mass number A{sub p}, energy per nucleon E{sub p} for projectile, and atomic number Z{sub T}, mass number A{sub T} for target. By inputting these basic data for projectile and target into this equation we can easily estimate the secondary neutron energy spectra at an emission angle of 0-90 deg. for bombardment with heavy ions and protons in the aforementioned energy region. This method will be quite useful to estimate the neutron source term in the neutron shielding design of high energy proton and heavy ion accelerators.

  5. L-subshell ionization studies of Au for α-particle and lithium-ion bombardment

    International Nuclear Information System (INIS)

    Dhal, B.B.; Nandi, T.; Padhi, H.C.; Trautmann, D.

    1995-01-01

    L-subshell ionization of Au has been investigated for α-particle and lithium-ion bombardments with energies 0.54-1.74 MeV u -1 and 0.65-1.44 MeV u -1 , respectively. Comparison of experimental x-ray production cross sections with the predictions of the ECPSSR and SCA theories shows reasonably good agreement for L α and L β x-rays, whereas for L γ and L γ1+5 the ECPSSR theory underestimates the cross sections by about 60% for both α-particle and lithium-ion impact, and the SCA theory agrees reasonably well. The ECPSSR theory underestimates the L 1 - and L 2 -subshell ionization cross sections and gives good agreement for the L 3 -subshell, whereas the SCA theory overestimates the L 3 -subshell ionization cross sections and gives good agreement for L 1 and L 2 . The experimental data for the total-ionization cross sections are within 25% of the predictions of both the theories. (Author)

  6. Direct and Recoil-Induced Electron Emission from Ion-Bombarded Solids

    DEFF Research Database (Denmark)

    Holmen, G.; Svensson, B.; Schou, Jørgen

    1979-01-01

    The kinetic emission of secondary electrons from ion-bombarded solid surfaces is split into two contributions, a direct one caused by ionizing collisions between the bombarding ion and target atoms, and an indirect one originating from ionizing collisions undergone by recoil atoms with other target...... atoms. The direct contribution, which has been treated by several authors in previous studies, shows a behavior that is determined primarily by the electronic stopping power of the bombarding ion, while the indirect contribution is nonproportionally related to the nuclear stopping power. This latter...

  7. Preliminary report into the effects of nitrogen ion bombardment treatment on mustard seeds

    International Nuclear Information System (INIS)

    Smith, C.W.; Al-Hashmi, S.A.R.; Ahmed, N.A.G.; Pollard, M.

    1988-01-01

    Mustard seeds have been subjected to nitrogen ion bombardment. A range of conditions was found within which there was an enhancement in the growth of seedlings from the ion bombardment treated seeds relative to those grown from control seeds. Scanning electron microscopy was used to examine seeds after treatment. It appeared that there had been an etching of the seed coating by the ion bombardment. This view was supported by experiments which showed that the rate of capillary water uptake by the treated seeds had been enhanced. (author)

  8. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.D., E-mail: yuld@thep-center.org [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sangwijit, K. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Phanchaisri, B. [Institute of Science and Technology Research, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongkumkoon, P. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Singkarat, S. [Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand); Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Anuntalabhochai, S. [Molecular Biology Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2014-05-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence.

  9. Mechanisms of ion-bombardment-induced DNA transfer into bacterial E. coli cells

    International Nuclear Information System (INIS)

    Yu, L.D.; Sangwijit, K.; Prakrajang, K.; Phanchaisri, B.; Thongkumkoon, P.; Thopan, P.; Singkarat, S.; Anuntalabhochai, S.

    2014-01-01

    Highlights: • Ion bombardment could induce DNA transfer into E. coli cells. • The DNA transfer induction depended on ion energy and fluence. • The mechanism was associated with the bacterial cell envelope structure. • A mechanism phase diagram was proposed to summarize the mechanism. - Abstract: As a useful ion beam biotechnology, ion-bombardment-induced DNA transfer into bacterial Escherichia coli (E. coli) cells has been successfully operated using argon ions. In the process ion bombardment of the bacterial cells modifies the cell envelope materials to favor the exogenous DNA molecules to pass through the envelope to enter the cell. The occurrence of the DNA transfer induction was found ion energy and fluence dependent in a complex manner. At ion energy of a few keV and a few tens of keV to moderate fluences the DNA transfer could be induced by ion bombardment of the bacterial cells, while at the same ion energy but to high fluences DNA transfer could not be induced. On the other hand, when the ion energy was medium, about 10–20 keV, the DNA transfer could not be induced by ion bombardment of the cells. The complexity of the experimental results indicated a complex mechanism which should be related to the complex structure of the bacterial E. coli cell envelope. A phase diagram was proposed to interpret different mechanisms involved as functions of the ion energy and fluence

  10. Auger emission from solid surfaces bombarded with ions

    International Nuclear Information System (INIS)

    Grizzi, Oscar.

    1986-01-01

    The Auger electron emission from Be, Na, Mg, Al and Si bombarded with 0,5-20 KeV noble gas ions is studied. Sharp structures of the Auger electron spectra of Na and Be were identified. A Monte Carlo program was adapted to simulate the colision cascade in the solid, inner shell excitations and Auger decays. From the comparision of experimental and simulated Auger intensities, the relative role of symmetric and asymmetric collisions in Be K- and Al L-shell excitation were evaluated. In the case of Be, the discussion of the exciting processes to higher projectile energies was extended. To this end, the simulation to early measurements of Be K X-ray yields was applied. From this analysis, information about the variations of the fluorescence yield and outer-shell occupation numbers of Be with projectile energy was obtained. The study of the shape of the sharp Auger structures and their dependence with the energy and incidence projectile angle gives information about the collisional processes, inner hole lifetimes and Auger decays. From the evaluation of the energy and angular distribution of the excited sputtered atoms and the interaction between them and the metallic-surface, the energy shift distributions in the Auger energies were obtained. From the comparison of these distributions with the experimental atomic peaks, the main causes of the broadening of these peaks were determined. (M.E.L.) [es

  11. Very low-energy and low-fluence ion beam bombardment of naked plasmid DNA

    International Nuclear Information System (INIS)

    Norarat, R.; Semsang, N.; Anuntalabhochai, S.; Yu, L.D.

    2009-01-01

    Ion beam bombardment of biological organisms has been recently applied to mutation breeding of both agricultural and horticultural plants. In order to explore relevant mechanisms, this study employed low-energy ion beams to bombard naked plasmid DNA. The study aimed at simulation of the final stage of the process of the ion beam bombardment of real cells to check whether and how very low-energy and low-fluence of ions can induce mutation. Argon and nitrogen ions at 5 keV and 2.5 keV respectively bombarded naked plasmid DNA pGFP to very low-fluences, an order of 10 13 ions/cm 2 . Subsequently, DNA states were analyzed using electrophoresis. Results provided evidences that the very low-energy and low-fluence ion bombardment indeed altered the DNA structure from supercoil to short linear fragments through multiple double strand breaks and thus induced mutation, which was confirmed by transfer of the bombarded DNA into bacteria Escherichia coli and subsequent expression of the marker gene.

  12. The interpretation of ellipsometric measurements of ion bombardment of noble gases on semiconductor surfaces

    NARCIS (Netherlands)

    Holtslag, A.H.M.; Slager, U.C.; van Silfhout, Arend

    1985-01-01

    Low energy noble gas ion bombardment and thermal desorption studies were carried out on Si(111) and analysed, in situ, using spectroscopic ellipsometry. The amorphous layer thickness and implanted noble gas fraction were calculated.

  13. Topography of InP surface bombarded by O2+ ion beam

    International Nuclear Information System (INIS)

    Sun Zhaoqi

    1997-01-01

    The topography of InP surface bombarded by O 2 + ion beam was investigated. Rippled topographies were observed for bombarded samples, and the data show that the ripple formation starts from a sputtering depth of about 0.4 μm. The wavelength and the disorder of the ripples both increase as the sputtering depth increases. The wavelength of the ripples appears to be sputtering depth dependent rather than sputtering rate dependent. It is confirmed that the ion-beam-induced surface rippling can be effectively suppressed by sample rotation during bombardment

  14. Effect of the ion bombardment on the apparent barrier height in GaAs Schottky junctions

    International Nuclear Information System (INIS)

    Horvath, Zs. J.

    1994-01-01

    The bombardment of the semiconductor with different particles often results in the change of the doping concentration at the semiconductor surface. In this paper the effects of this near-interface concentration change on the apparent and real Schottky barrier heights are discussed. Experimental results obtained in GaAs Schottky junctions prepared on ion-bombarded semiconductor surfaces are analysed, and it is shown that their electrical characteristics are strongly influenced by the near-interface concentration change due to the ion bombardment. (author). 36 refs., 2 figs

  15. Influence of the ion bombardment of O{sub 2} plasmas on low-k materials

    Energy Technology Data Exchange (ETDEWEB)

    Verdonck, Patrick, E-mail: verdonck@imec.be [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Samara, Vladimir [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Goodyear, Alec [Open University, Materials Engineering, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Ferchichi, Abdelkarim; Van Besien, Els; Baklanov, Mikhail R. [IMEC, Kapeldreef 75, 3001 Leuven (Belgium); Braithwaite, Nicholas [Open University, Department of Physics and Astronomy, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2011-10-31

    In this study, special tests were devised in order to investigate the influence of ion bombardment on the damage induced in low-k dielectrics by oxygen plasmas. By placing a sample that suffered a lot of ion bombardment and one which suffered little ion bombardment simultaneously in the same plasma, it was possible to verify that ion bombardment in fact helped to protect the low-k film against oxygen plasma induced damage. Exhaustive analyses (ellipsometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, porosimetry, capacitance-voltage (C-V) measurements, water contact angle analysis) show that ion bombardment induced the formation of a denser top layer in the film, which then hampered further penetration of active oxygen species deeper into the bulk. This was further confirmed by other tests combining capacitively and inductively coupled plasmas. Therefore, it was possible to conclude that, at least for these plasmas, ion bombardment may help to reduce plasma induced damage to low-k materials.

  16. Effect of helium ion bombardment on hydrogen behaviour in stainless steel

    International Nuclear Information System (INIS)

    Guseva, M.I.; Stolyarova, V.G.; Gorbatov, E.A.

    1987-01-01

    The effect of helium ion bombardment on hydrogen behaviour in 12Kh18N10T stainless steel is investigated. Helium and hydrogen ion bombardment was conducted in the ILU-3 ion accelerator; the fluence and energy made up 10 16 -5x10 17 cm -2 , 30 keV and 10 16 -5x10 18 cm -2 , 10 keV respectively. The method of recoil nuclei was used for determination of helium and hydrogen content. Successive implantation of helium and hydrogen ions into 12Kh18N10T stainless steel results in hydrogen capture by defects formed by helium ions

  17. Self-Assembled Gold Nano-Ripple Formation by Gas Cluster Ion Beam Bombardment.

    Science.gov (United States)

    Tilakaratne, Buddhi P; Chen, Quark Y; Chu, Wei-Kan

    2017-09-08

    In this study, we used a 30 keV argon cluster ion beam bombardment to investigate the dynamic processes during nano-ripple formation on gold surfaces. Atomic force microscope analysis shows that the gold surface has maximum roughness at an incident angle of 60° from the surface normal; moreover, at this angle, and for an applied fluence of 3 × 10 16 clusters/cm², the aspect ratio of the nano-ripple pattern is in the range of ~50%. Rutherford backscattering spectrometry analysis reveals a formation of a surface gradient due to prolonged gas cluster ion bombardment, although the surface roughness remains consistent throughout the bombarded surface area. As a result, significant mass redistribution is triggered by gas cluster ion beam bombardment at room temperature. Where mass redistribution is responsible for nano-ripple formation, the surface erosion process refines the formed nano-ripple structures.

  18. Impact of Ion Bombardment on the Structure and Magnetic Properties of Fe78Si13B9 Amorphous Alloy

    Science.gov (United States)

    Wu, Yingwei; Peng, Kun

    2018-06-01

    Amorphous Fe78Si13B9 alloy ribbons were bombarded by ion beams with different incident angles ( θ ). The evolution of the microstructure and magnetic properties of ribbons caused by ion beam bombardment was investigated by x-ray diffraction, transmission electron microscope and vibrating sample magnetometer analysis. Low-incident-angle bombardment led to atomic migration in the short range, and high-incident-angle bombardment resulted in the crystallization of amorphous alloys. Ion bombardment induces magnetic anisotropy and affects magnetic properties. The effective magnetic anisotropy was determined by applying the law of approach to saturation, and it increased with the increase of the ion bombardment angle. The introduction of effective magnetic anisotropy will reduce the permeability and increase the relaxation frequency. Excellent high-frequency magnetic properties can be obtained by selecting suitable ion bombardment parameters.

  19. High Energy Ion Bombardment Simulation Facility at the University of Pittsburgh

    International Nuclear Information System (INIS)

    McGruer, J.N.; Choyke, W.J.; Doyle, N.J.; Spitznagel, J.A.

    1975-01-01

    The High Energy Ion Bombardment Simulation (HEIBS) Facility located at the University of Pittsburgh is now operational. The E-22 tandem accelerator of the Nuclear Physics Laboratory, fitted with a UNIS source, provides the heavy high energy ions. An auxiliary Van de Graaff accelerator is used for the simultaneous production of He ions. Special features of the simulation laboratory are reported

  20. Measurement of electron emission due to energetic ion bombardment in plasma source ion implantation

    Science.gov (United States)

    Shamim, M. M.; Scheuer, J. T.; Fetherston, R. P.; Conrad, J. R.

    1991-11-01

    An experimental procedure has been developed to measure electron emission due to energetic ion bombardment during plasma source ion implantation. Spherical targets of copper, stainless steel, graphite, titanium alloy, and aluminum alloy were biased negatively to 20, 30, and 40 kV in argon and nitrogen plasmas. A Langmuir probe was used to detect the propagating sheath edge and a Rogowski transformer was used to measure the current to the target. The measurements of electron emission coefficients compare well with those measured under similar conditions.

  1. Ion bombardment effects on the fatigue life of stainless steel under simulated fusion first wall conditions

    International Nuclear Information System (INIS)

    Kohse, G.; Harling, O.K.

    1983-01-01

    Pressurized tube specimens have been exposed to simultaneous multi-energy surface ion bombardment, fast neutron irradiation and stress and temperature cycling, in a simulation of a possible fusion reactor first wall environment. After ion bombardments equivalent to months-years of reactor operation and up to 30,000 cycles, no detrimental effects on post-irradiation fatigue life were found. The ion damage is found to enhance surface cracking, but this effect is limited to the several micron surface layer in which the ions are implanted

  2. Angular dependence of secondary ion emission from silicon bombarded with inert gas ions

    International Nuclear Information System (INIS)

    Wittmaack, K.

    1984-01-01

    The emission of positive and negative, atomic and molecular secondary ions sputtered from silicon has been studied under ultrahigh vacuum conditions. The sample was bombarded with 2-12 keV Ar + and Xe + ions at angles of incidence between 0 0 and 60 0 to the surface normal. The angular dependence of the secondary ion intensity as well as the energy spectra of Si + and Si - were found to differ significantly. The effect is attributed mostly do differences in the rate of neutralization. The stability of molecular ions appears to be independent of the charge state. Supporting evidence is provided for the idea that multiply charged secondary ions are due to Auger de-excitation of sputtered atoms in vacuum. (orig.)

  3. Target bombardment by ion beams generated in the Focus experiment

    International Nuclear Information System (INIS)

    Bernard, Alain; Coudeville, Alain; Garconnet, J.-P.; Jolas, A.; Mascureau, J. de; Nazet, Christian.

    1976-01-01

    In a Mather-Focus experiment, it was shown that 80% of the neutron emitted were generated through bombardment. The apparatus was operated with various targets at a distance of 13mm from the anode. In the low pressure regime, a deuteron beam of high energy was produced. Its emission duration was measured using a CD 2 target [fr

  4. Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

    Energy Technology Data Exchange (ETDEWEB)

    Awazu, Kaoru; Yoshida, Hiroyuki [Industrial Research Inst. of Ishikawa (Japan); Watanabe, Hiroshi [Gakushuin Univ., Tokyo (Japan); Iwaki, Masaya; Guzman, L [RIKEN, Saitama (Japan)

    1992-04-15

    A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C{sub 6}H{sub 6} gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10{sup 16} ions cm{sup -2}. The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.).

  5. Effects of ion beam bombardment of carbon thin films deposited onto tungsten carbide and tool steels

    International Nuclear Information System (INIS)

    Awazu, Kaoru; Yoshida, Hiroyuki; Watanabe, Hiroshi; Iwaki, Masaya; Guzman, L.

    1992-01-01

    A study was made of the effects of argon ion bombardment of carbon thin films deposited onto WC and tool steels. Carbon thin film deposition was performed at various temperatures ranging from 200degC to 350degC, using C 6 H 6 gas. Argon ion beam bombardment of the films was carried out at an energy of 150 keV with a dose of 1x10 16 ions cm -2 . The hardness and adhesion of the films were measured by means of Knoop hardness and scratch tests respectively. The structure of the carbon films was estimated by laser Raman spectroscopy, and the relations were investigated between the mechanical properties and the structure of the films. The hardness of carbon thin films increases as their deposition temperature decreases; this tendency corresponds to the increase in amorphous structure estimated by Raman spectra. Argon ion bombardment results in constant hardness and fraction of amorphous structure. Argon ion beam bombardment of films prior to additional carbon deposition may cause the adhesion of the subsequently deposited films to improve. It is concluded that argon ion beam bombardment is useful for improving the properties of carbon films deposited onto WC and tool steels. (orig.)

  6. Evidence of incomplete relaxation in the reaction Ag+40Ar at 288 and 340 MeV bombarding energies

    International Nuclear Information System (INIS)

    Galin, J.; Moretto, L.G.; Babinet, R.; Schmitt, R.; Jared, R.; Thompson, S.G.

    1975-01-01

    The particles emitted in the reaction induced by 40 Ar on natural Ag at 288 and 340 MeV bombarding energy have been studied. The fragments have been identified in atomic number, their kinetic energy distribution and their angular distributions have been measured. The kinetic energy spectra show two components: a high-energy component related to the beam energy, or quasi-elastic component, and a low kinetic energy component, close to the Coulomb energy called relaxed component. The relaxed component is present at all angles and for all particles. The quasi-elastic component is present close to the grazing angle for atomic numbers close to that of the projectile. The relaxed cross section increases with atomic number for Z>9. The increase in cross section is sharper for the lower bombarding energy. The angular distributions are forward peaked, in excess of 1/sin(theta) for all the measured atomic numbers. The forward peaking is larger for particles close in Z to the projectile. The results are interpreted in terms of characteristic times associated with a short-lived intermediate complex. The cross sections and angular distributions are satisfactorily reproduced on the basis of a model accounting for a diffusion process occurring along the mass asymmetry coordinate of the intermediate complex. (Auth.)

  7. Evolution of atomic-scale surface structures during ion bombardment: A fractal simulation

    International Nuclear Information System (INIS)

    Shaheen, M.A.; Ruzic, D.N.

    1993-01-01

    Surfaces of interest in microelectronics have been shown to exhibit fractal topographies on the atomic scale. A model utilizing self-similar fractals to simulate surface roughness has been added to the ion bombardment code TRIM. The model has successfully predicted experimental sputtering yields of low energy (less then 1000 eV) Ar on Si and D on C using experimentally determined fractal dimensions. Under ion bombardment the fractal surface structures evolve as the atoms in the collision cascade are displaced or sputtered. These atoms have been tracked and the evolution of the surface in steps of one monolayer of flux has been determined. The Ar--Si system has been studied for incidence energies of 100 and 500 eV, and incidence angles of 0 degree, 30 degree, and 60 degree. As expected, normally incident ion bombardment tends to reduce the roughness of the surface, whereas large angle ion bombardment increases the degree of surface roughness. Of particular interest though, the surfaces are still locally self-similar fractals after ion bombardment and a steady state fractal dimension is reached, except at large angles of incidence

  8. Effects of low-energy ion beam bombardment on metal oxides

    International Nuclear Information System (INIS)

    Sullivan, J.L.; Saied, S.O.; Choudhury, T.

    1993-01-01

    This paper describes a study of Ar ion bombardment damage in metal oxides. In the energy range 1 to 5 keV, preferential oxygen removal and reduction of the oxides was found to depend on ion current density, but to be independent of beam energy. (author)

  9. Effect of ion beam bombardment on the carbide in M2 steel modified by ion-beam-assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.Y.; Wang, F.J.; Wang, Y.K. (Dept. of Materials Engineering, Dalian Univ. of Technology (China)); Ma, T.C. (National Lab. of Materials Modification by Beam Three, Dalian (China))

    1991-10-30

    Transmission electron microscopy was used to study the effect of nitrogen ion bombardment with different doses on the carbides in M2 high speed steel as the nitrogen ions penetrated into the nitride films during ion-beam-assisted deposition. With different doses of nitrogen, alterations in the morphological characteristics of the carbide M6C at the interface were observed. With lower doses, knitting-like contrast within the carbide showed subboundary structure defects in M6C. With increasing dose, the substructure defects were broken up into small fragments owing to heavy bombardment. The microstructures of carbides at the interface damaged by nitrogen ions are discussed in detail. (orig.).

  10. The surface topography of Inconel, stainless steel and copper after argon ion bombardment

    International Nuclear Information System (INIS)

    Vogelbruch, K.; Vietzke, E.

    1983-01-01

    Energetic particle bombardment of metals is known to change the surface topography. To simulate the behaviour of the first wall of a fusion device under real plasma conditions, we have investigated the surface topography of rotating targets after 30 keV argon ion bombardment at 70deg incident angle by electron scanning micrographs. Under these conditions Inconel 600, 601, 625, stainless steel, and copper showed no cones, pyramids or cliffs, but only etching figures and at higher ion doses relatively flat hills. Thus, it can be concluded, that the influence of energetic particles on the first wall of a fusion reactor is smaller than expected from the results of such sputtering experiments, which have dealt with the formation of surface structures under ion bombardment at constant incident direction. (author)

  11. Alteration of the UV-visible reflectance spectra of H2O ice by ion bombardment

    Science.gov (United States)

    Sack, N. J.; Boring, J. W.; Johnson, R. E.; Baragiola, R. A.; Shi, M.

    1991-01-01

    Satellite in the Jovian and Saturnian system exhibit differences in reflectivity between their 'leading' and 'trailing' surfaces which can affect the local vapor pressure. Since these differences are thought to be due to differences in the flux of bombarding magnetospheric ions, the influence of ion impact on the UV-visible reflectance of water ice surfaces (20-90 K) by keV ion bombardment was studied. An observed decrease in reflectance in the UV is attributed to rearrangement processes that affect the physical microstructure and surface 'roughness'. The ratio in reflectance of bombarded to freshly deposited films is compared to the ratio of the reflectance of the leading and trailing hemispheres for Europa and Ganymede.

  12. InN: Fermi level stabilization by low-energy ion bombardment

    International Nuclear Information System (INIS)

    Piper, L.F.J.; Veal, T.D.; McConville, C.F.; Lu, H.; Schaff, W.J.

    2006-01-01

    The near-surface electronic properties of InN have been investigated with high-resolution electron-energy loss spectroscopy. Low-energy (∝400 eV) nitrogen ion bombardment followed by low temperature annealing (<300 C) was found to dramatically increase the n-type conductivity of InN, close to the surface. This is explained in terms of the formation of amphoteric defects from the ion bombardment and annealing combined with the band structure of InN. Low-energy ion bombardment and annealing is shown to result in a damage-induced, donor-like defect-profile instead of the expected electron accumulation for InN. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. Pt.2. Charge and mass analysis at 217MeV bombarding energy

    International Nuclear Information System (INIS)

    Galin, J.; Gatty, B.; Guerreau, D.; Lefort, M.; Tarrago, X.; Agarwal, S.; Babinet, R.; Cauvin, B.; Girard, J.; Nifenecker, H.

    1977-01-01

    Atomic numbers and masses have been identified for the fragments (12 40 Ar (217MeV) + 197 Au. Even for such a large mass asymmetry in the entrance channel it is shown how difficult it is, for some part of the cross section, to distinguish between a classical deep inelastic phenomenon and the formation of a true compound nucleus followed by symmetric fission. The two reaction mechanisms are then studied separately in a critical way comparing with existing models

  14. Measurement of activation reaction rate distributions in a lead assembly bombarded with 500-MeV protons

    CERN Document Server

    Takada, H; Sasa, T; Tsujimoto, K; Yasuda, H

    2000-01-01

    Reaction rate distributions of various activation detectors such as the /sup nat/Ni(n, x)/sup 58/Co, /sup 197/Au(n,2n)/sup 196/Au, and /sup 197/Au(n,4n)/sup 194/Au reactions were measured to study the production and the transport of spallation neutrons in a lead assembly bombarded with protons of 500 MeV. The measured data were analyzed with the nucleon-meson transport code NMTC/JAERI combined with the MCNP4A code using the nuclide production cross sections based on the JENDL Dosimetry File and those calculated with the ALICE-F code. It was found that the NMTC/JAERI-MCNP4A calculations agreed well with the experiments for the low-energy-threshold reaction of /sup nat/Ni(n, x)/sup 58/Co. With the increase of threshold energy, however, the calculation underestimated the experiments, especially above 20 MeV. The reason for the disagreement can be attributed to the underestimation of the neutron yield in the tens of mega-electron-volt regions by the NMTC/JAERI code. (32 refs).

  15. Experiment and analysis of neutron spectra in a concrete assembly bombarded by 14 MeV neutrons

    International Nuclear Information System (INIS)

    Oishi, Koji; Tomioka, Kazuyuki; Ikeda, Yujiro; Nakamura, Tomoo.

    1988-01-01

    Neutron spectrum in concrete bombarded by 14 MeV neutrons was measured using a miniature NE213 spectrometer and multi-foil activation method. A good agreement between those two experimental methods was obtained within experimental errors. The measured spectrum was compared with calculated ones using two-dimensional transport code DOT3.5 with 125 group structure cross section libraries based on ENDF/B-IV, JENDL-2, and JENDL-3T (the testing version of JENDL-3.) In the D-T neutron peak region, measured and calculated neutron spectra agreed well with each other for those libraries. However, disagreements of about -10 % to +50 % and -30 % to +40 % were obtained in the MeV region and still lower neutron energy range, respectively. As a result, it was concluded that those discrepancies were caused by the overestimation of secondary neutrons emitted by inelastic scattering from O, Si, and/or Ca which were the main components of concrete. (author)

  16. Statistical characterization of surface defects created by Ar ion bombardment of crystalline silicon

    International Nuclear Information System (INIS)

    Ghazisaeidi, M.; Freund, J. B.; Johnson, H. T.

    2008-01-01

    Ion bombardment of crystalline silicon targets induces pattern formation by the creation of mobile surface species that participate in forming nanometer-scale structures. The formation of these mobile species on a Si(001) surface, caused by sub-keV argon ion bombardment, is investigated through molecular dynamics simulation of Stillinger-Weber [Phys. Rev. B 31, 5262 (1985)] silicon. Specific criteria for identifying and classifying these mobile atoms based on their energy and coordination number are developed. The mobile species are categorized based on these criteria and their average concentrations are calculated

  17. Ion bombardment induced surface topography modification of clean and contaminated single crystal Cu and Si

    International Nuclear Information System (INIS)

    Lewis, G.W.; Kiriakides, G.; Carter, G.; Nobes, M.J.

    1982-01-01

    Among the several factors which lead to depth resolution deterioration during sputter profiling, surface morphological modification resulting from local differences of sputtering rate can be important. This paper reports the results of direct scanning, electron microscopic studies obtained quasi-dynamically during increasing fluence ion bombardment of the evolution of etch pit structures on Si and Cu, and how such elaboration may be suppressed. It also reports on the elaboration of contaminant-induced cone generation for different ion species bombardment. The influence of such etch pit and cone generation on achievable depth resolution is assessed. (author)

  18. The influence of ion bombardment on emission properties of carbon materials

    International Nuclear Information System (INIS)

    Chepusov, Alexander; Komarskiy, Alexander; Kuznetsov, Vadim

    2014-01-01

    When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

  19. The influence of ion bombardment on emission properties of carbon materials

    Energy Technology Data Exchange (ETDEWEB)

    Chepusov, Alexander, E-mail: chepusov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Komarskiy, Alexander, E-mail: aakomarskiy@gmail.com [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation); Ural Federal University, 620002, 19 Mira Street, Ekaterinburg (Russian Federation); Kuznetsov, Vadim, E-mail: kuznetsov@iep.uran.ru [The Institute of Electrophysics of the Ural Division of the Russian Academy of Sciences (IEP UD RAS), 620016, 106 Amundsen Street, Ekaterinburg (Russian Federation)

    2014-07-01

    When electric-vacuum device works its cathode surface experiences bombardment with ions of residual gases. Effects of ion bombardment impact on surface of field emission cathodes made of carbon materials may essentially change emission properties of such cathodes. It changes emission start electric field strength, voltage vs. current characteristic of material, its relief and electron structure of the surface layer. Field emission cathode operating mode, variation of radiation doses allow to obtain both good effects: maximal electric current, surface recovery – and negative ones: the worst emission properties and surface destruction, amorphization.

  20. Phenomenology of the plastic flow of amorphous solids induced by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Klaumuenzer, S.; Benyagoub, A.

    1991-01-01

    Amorphous solids exhibit at temperatures far below the glass transition plastic flow when bombarded with fast heavy ions (kinetic energy ∼1 MeV/u). The dimensions perpendicular to the ion beam grow whereas the sample dimension parallel to the ion beam shrinks. The strain tensor describing phenomenologically these dimensional changes is derived from symmetry considerations and compared with experiment. Particular attention is devoted to angular changes, which have not been discussed in this context so far

  1. Excited-atom production by electron and ion bombardment of alkali halides

    International Nuclear Information System (INIS)

    Walkup, R.E.; Avouris, P.; Ghosh, A.P.

    1987-01-01

    We present experimental results on the production of excited atoms by electron and ion bombardment of alkali halides. For the case of electron bombardment, Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the systematic dependence on incident electron current and sample temperature support a model in which the excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. In contrast, for the case of ion bombardment, the excited atoms are directly sputtered from the surface, with velocity distributions characteristic of a collision cascade, and with typical energies of --10 eV

  2. Kinetics of interaction from low-energy-ion bombardment of surfaces

    International Nuclear Information System (INIS)

    Horton, C.C.

    1988-01-01

    The kinetics of interaction from low energy oxygen ion bombardment of carbon and Teflon surfaces have been investigated. The surfaces were bombarded with 4.5 to 93 eV oxygen ions and emitted species were observed with a mass spectrometer. To obtain the kinetic information, the ion beam was square pulse modulated and reaction products were observed as a function of time. The kinetic information is contained in the response of the emitted species to the pulsed ion beam. Oxygen bombardment of carbon produced CO in three parallel branches with each following an adsorption-desorption process. The fast branch, with a rate constants of 12,000/sec, appeared to be sputter induced an was absent below about 19 eV. The medium and slow branches, with rate constants of 850/sec and 45/sec respectively, has little energy dependence and appeared to be due to chemical sputtering from two sites. The ratio of the fraction of the medium branch to that of the slow was constant at 1:3. The bombardment of Teflon produced CF in two parallel branches, with one following a series process and the other an adsorb-desorb process. The rate constant of the other branch were 22,000/sec and 7,000/sec and the rate constant of the other branch was 90/sec. The total signal fell monotonically with decreasing ion energy with the fraction for each branch holding constant at 71% for the series and 29% for the adsorb-desorb

  3. Friction and wear measurements of sputtered MoS/sub x/ films amorphized by ion bombardment

    International Nuclear Information System (INIS)

    Mikkelsen, N.J.; Chevallier, J.; Soerensen, G.; Straede, C.A.

    1988-01-01

    The present study presents an experimental evidence for amorphization of rf sputtered MoS/sub x/ films by ion bombardment. Even at low doses (3 x 10 15 ions/cm 2 ) of 400 keV argon ions a complete amorphization was confirmed by x-ray diffraction analysis and transmission electron microscopy. As a result of the ion bombardment the film density increased 100% to almost the bulk value for MoS 2 . The friction coefficient for ion beam amorphized MoS/sub x/ was measured to be 0.04 in agreement with the values reported for crystalline films but disagreeing considerably with the friction coefficient of 0.4 previously reported for amorphous films

  4. In-Situ atomic force microscopic observation of ion beam bombarded plant cell envelopes

    International Nuclear Information System (INIS)

    Sangyuenyongpipat, S.; Yu, L.D.; Brown, I.G.; Seprom, C.; Vilaithong, T.

    2007-01-01

    A program in ion beam bioengineering has been established at Chiang Mai University (CMU), Thailand, and ion beam induced transfer of plasmid DNA molecules into bacterial cells (Escherichia coli) has been demonstrated. However, a good understanding of the fundamental physical processes involved is lacking. In parallel work, onion skin cells have been bombarded with Ar + ions at energy 25 keV and fluence1-2 x 10 15 ions/cm 2 , revealing the formation of microcrater-like structures on the cell wall that could serve as channels for the transfer of large macromolecules into the cell interior. An in-situ atomic force microscope (AFM) system has been designed and installed in the CMU bio-implantation facility as a tool for the observation of these microcraters during ion beam bombardment. Here we describe some of the features of the in-situ AFM and outline some of the related work

  5. Influence of ion bombardment on growth and properties of PLD created DLC films

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Písařík, Petr; Kocourek, Tomáš; Zemek, Josef; Lukeš, J.

    2013-01-01

    Roč. 110, č. 4 (2013), s. 943-947 ISSN 0947-8396 R&D Projects: GA MŠk LD12069 Institutional research plan: CEZ:AV0Z10100522 Keywords : DLC * ion bombardment * sp3 /sp2 * thin films * PLD Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.694, year: 2013

  6. A note on the random walk theory of recoil movement in prolonged ion bombardment

    International Nuclear Information System (INIS)

    Koponen, Ismo

    1994-01-01

    A characteristic function is derived for the probability distribution of final positions of recoil atoms in prolonged ion bombardment of dense matter. The derivation is done within the framework of Poissonian random walk theory using a jump distribution, which is somewhat more general than those studied previously. ((orig.))

  7. Comparison of Se and Te clusters produced by ion bombardment

    Directory of Open Access Journals (Sweden)

    Trzyna Małgorzata

    2017-01-01

    Full Text Available Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS. It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to ~ 1300 m/z. Local maxima or minima (magic numbers are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  8. Comparison of Se and Te clusters produced by ion bombardment

    Science.gov (United States)

    Trzyna, Małgorzata

    2017-01-01

    Nanostructures based on tellurium and selenium are materials used as components for the manufacturing topological insulators. Therefore it is crucial to precisely characterize these materials. In this work the emission of selenium and tellurium cluster ions, sputtered by Bi+ primary ion guns, was investigated by using Time-of-Flight Secondary Ion Mass Spectrometry (TOF SIMS). It has been found that BixTex and BixSex clusters appear in addition to Sex and Tex clusters in the mass range up to 1300 m/z. Local maxima or minima (magic numbers) are observed in the ion intensity versus a number of atoms per cluster for both positive and negative ions spectra for all types of clusters and primary ions used. These extrema can be attributed to different yield and stability of certain clusters but also to fragmentation of high-mass clusters.

  9. Formation of a highly doped ultra-thin amorphous carbon layer by ion bombardment of graphene

    Science.gov (United States)

    Piotr Michałowski, Paweł; Pasternak, Iwona; Ciepielewski, Paweł; Guinea, Francisco; Strupiński, Włodek

    2018-07-01

    Ion bombardment of graphene leads to the formation of defects which may be used to tune properties of the graphene based devices. In this work, however, we present that the presence of the graphene layer on a surface of a sample has a significant impact on the ion bombardment process: broken sp2 bonds react with the incoming ions and trap them close to the surface of the sample, preventing a standard ion implantation. For an ion bombardment with a low impact energy and significant dose (in the range of 1014 atoms cm‑2) an amorphization of the graphene layer is observed but at the same time, most of the incoming ions do not penetrate the sample but stop at the surface, thus forming a highly doped ultra-thin amorphous carbon layer. The effect may be used to create thin layers containing desired atoms if no other technique is available. This approach is particularly useful for secondary ion mass spectrometry where a high concentration of Cs at the surface of a sample significantly enhances the negative ionization probability, allowing it to reach better detection limits.

  10. Films deposited from reactive sputtering of aluminum acetylacetonate under low energy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Battaglin, Felipe Augusto Darriba; Prado, Eduardo Silva; Cruz, Nilson Cristino da; Rangel, Elidiane Cipriano, E-mail: elidiane@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Caseli, Luciano [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas; Silva, Tiago Fiorini da; Tabacniks, Manfredo Harri [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

    2017-07-15

    Films were deposited from aluminum acetylacetonate (Al(acac)3 ) using a methodology involving reactive sputtering and low energy ion bombardment. The plasma was generated by the application of radiofrequency power to the powder containing electrode and simultaneously, negative pulses were supplied to the electrode where the substrates were attached. It was investigated the effect of the duty cycle of the pulses (Δ) on the properties of the coatings. Association of ion bombardment to the deposition process increased film thickness, structure reticulation and organic content. Ions from the deposition environment were implanted at the film-air interface or underneath it. Morphology and topography were altered depending on Δ. Considering the enhancement of Δ, it affected the flux of ions reaching the depositing interface and then the deposition rate, H content, crosslinking degree and surface microstructure. Alumina groups were detected in the infrared spectra, whereas the precipitation of amorphous alumina was confirmed by X-ray diffraction. (author)

  11. The effect of incidence angle on ion bombardment induced surface topography development on single crystal copper

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Lewis, G.W.; Whitton, J.L.

    1982-01-01

    The fluence dependence of development of microscopic surface features, particularly etch pits, during 9 keV Ar + ion bombardment of (11,3,1) oriented Cu single crystals has been studied employing quasi-dynamic irradiation and observation techniques in a scanning electron microscope-accelerator system. 9 keV ions are observed not to produce crystallographic pyramids under all irradiation conditions for this surface, a very different result from our earlier studies with higher energy ions. The bombardment does elaborate etch pits however, the habits and growth kinetics of which depend upon both polar and azimuthal angles of ion incidence to the surface. The results are explained in terms of differential erosion of crystal planes modified by the presence of pre-existing and irradiation induces extended defects. (orig.)

  12. Ion bombardment induced smoothing of amorphous metallic surfaces: Experiments versus computer simulations

    International Nuclear Information System (INIS)

    Vauth, Sebastian; Mayr, S. G.

    2008-01-01

    Smoothing of rough amorphous metallic surfaces by bombardment with heavy ions in the low keV regime is investigated by a combined experimental-simulational study. Vapor deposited rough amorphous Zr 65 Al 7.5 Cu 27.5 films are the basis for systematic in situ scanning tunneling microscopy measurements on the smoothing reaction due to 3 keV Kr + ion bombardment. The experimental results are directly compared to the predictions of a multiscale simulation approach, which incorporates stochastic rate equations of the Langevin type in combination with previously reported classical molecular dynamics simulations [Phys. Rev. B 75, 224107 (2007)] to model surface smoothing across length and time scales. The combined approach of experiments and simulations clearly corroborates a key role of ion induced viscous flow and ballistic effects in low keV heavy ion induced smoothing of amorphous metallic surfaces at ambient temperatures

  13. Modelling and simulation of surface morphology driven by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Yewande, E.O.

    2006-05-02

    Non-equilibrium surfaces, at nanometer length scales, externally driven via bombardment with energetic particles are known to exhibit well ordered patterns with a variety of applications in nano-technology. These patterns emerge at time scales on the order of minutes. Continuum theory has been quite successful in giving a general picture of the processes that interplay to give the observed patterns, as well as how such competition might determine the properties of the nanostructures. However, continuum theoretical descriptions are ideal only in the asymptotic limit. The only other theoretical alternative, which happens to be more suitable for the characteristic length-and time-scales of pattern formation, is Monte Carlo simulation. In this thesis, surface morphology is studied using discrete solid-on-solid Monte Carlo models of sputtering and surface diffusion. The simulations are performed in the context of the continuum theories and experiments. In agreement with the experiments, the ripples coarsen with time and the ripple velocity exhibits a power-law behaviour with the ripple wavelength, in addition, the exponent was found to depend on the simulation temperature, which suggests future experimental studies of flux dependence. Moreover, a detailed exploration of possible topographies, for different sputtering conditions, corresponding to different materials, was performed. And different surface topographies e.g. holes, ripples, and dots, were found at oblique incidence, without sample rotation. With sample rotation no new topography was found, its only role being to destroy any inherent anisotropy in the system. (orig.)

  14. Effects of uranium bombardment by 20-40 KeV argon ions, Annex 2

    International Nuclear Information System (INIS)

    Nenadovic, T.; Jurela, Z.

    1966-01-01

    This paper shows the results of argon ions interaction with the polycrystal natural uranium. Thin foil of uranium about 200 μ was bombarded by 20-40 KeV argon ions. Coefficients of cathode scattering δ and secondary electrons emission γ were measured, during the process A + →U. The foil was then studied by transmission method and method of single step replica using an electron microscope [sr

  15. Silicon transport in sputter-deposited tantalum layers grown under ion bombardment

    International Nuclear Information System (INIS)

    Gallais, P.; Hantzpergue, J.J.; Remy, J.C.; Roptin, D.

    1988-01-01

    Tantalum was sputter deposited on (111) Si substrate under low-energy ion bombardment in order to study the effects of the ion energy on the silicon transport into the Ta layer. The Si substrate was heated up to 500 0 C during growth. For ion energies up to 180 eV silicon is not transported into tantalum and the growth temperature has no effect. An ion bombardment energy of 280 eV enhances the transport of silicon throughout the tantalum layer. Growth temperatures up to 300 0 C have no effect on the silicon transport which is mainly enhanced by the ion bombardment. For growth temperatures between 300 and 500 0 C, the silicon transport is also enhanced by the thermal diffusion. The experimental depth distribution of silicon is similar to the theoretical depth distribution calculated for the case of an interdiffusion. The ion-enhanced process of silicon transport is characterized by an activation energy of 0.4 eV. Silicon into the layers as-grown at 500 0 C is in both states, amorphous silicide and microcrystalline cubic silicon

  16. MEV Energy Electrostatic Accelerator Ion Beam Emittance Measurement

    OpenAIRE

    I.G. Ignat’ev; M.I. Zakharets; S.V. Kolinko; D.P. Shulha

    2014-01-01

    The testing equipment was designed, manufactured and tried out permitting measurements of total current, current profile and emittance of an ion beam extracted from the ion beam. MeV energy electrostatic accelerator ion H + beam emittance measurement results are presented.

  17. Forming controlled inset regions by ion implantation and laser bombardment

    International Nuclear Information System (INIS)

    Gibbons, J.F.

    1981-01-01

    A semiconductor integrated circuit structure in which the inset regions are ion implanted and laser annealed to maintain substantially the dimensions of the implantation and the method of forming inset implanted regions having controlled dimensions

  18. Fast neutron distributions from Be and C thick targets bombarded with 80 and 160 MeV deuterons

    International Nuclear Information System (INIS)

    Pauwels, N.; Laurent, H.; Clapier, F.; Brandenburg, S.; Beijers, J. P .M.; Zegers, R. G. T.; Lebreton, H.; Saint-Laurent, M.G.; Mirea, M.

    2001-01-01

    Production of fast neutron studies have come to the fore in the past few years because of the great interest for the possible applications of induced fission to produce neutron rich ion beams. In this context, the main objective of the SPIRAL II (Systeme de Production d'Ions Radioactifs Acceleres en Ligne) and PARRNe (Production d'Atomes Radioactifs Riches en Neutrons) R and D projects is the investigation of the feasibility and of the optimum parameters for a neutron rich isotope source. Special attention is dedicated to the energy and angular distributions of the neutrons obtained through deuteron break--up in different types of converters and different incident energies. Analysis and modelling of such behaviors, together with the study of the yields of neutron induced fission, can be used to optimize the productivity of the fissioning target its geometry and designing it accordingly. The present report continues our previous studies realised for 17, 20, 28 and 200 MeV deuteron energies and it is focused on deuteron incident energies of 80 and 160 MeV. In the experiment, the double differential cross section for neutron production induced by 80 and 160 MeV deuterons impinging on thick C and Be targets, in which the incident deuterons were complete stopped, have been measured. The energy of the neutrons was determined from the time--of--flight (TOF) measurement. To obtain an energy resolution of about 4% for the fastest, forward--emitted neutrons, which have approximately beam velocity, the length of the flightpath for the detectors at angles up to 30 angle was chosen to be 6 m. At backward angles, where the neutron energies are lower, a shorter flightpath was chosen. A schematic drawing of the setup is shown. A 100 mm thick Be target and a 70 mm thick C target were used. Results are exemplified with the angular and energy distributions of neutron obtained for Be target at 80 MeV. (authors)

  19. Highly Stripped Ion Sources for MeV Ion Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Hershcovitch, Ady

    2009-06-30

    Original technical objectives of CRADA number PVI C-03-09 between BNL and Poole Ventura, Inc. (PVI) were to develop an intense, high charge state, ion source for MeV ion implanters. Present day high-energy ion implanters utilize low charge state (usually single charge) ion sources in combination with rf accelerators. Usually, a MV LINAC is used for acceleration of a few rnA. It is desirable to have instead an intense, high charge state ion source on a relatively low energy platform (de acceleration) to generate high-energy ion beams for implantation. This de acceleration of ions will be far more efficient (in energy utilization). The resultant implanter will be smaller in size. It will generate higher quality ion beams (with lower emittance) for fabrication of superior semiconductor products. In addition to energy and cost savings, the implanter will operate at a lower level of health risks associated with ion implantation. An additional aim of the project was to producing a product that can lead to long­ term job creation in Russia and/or in the US. R&D was conducted in two Russian Centers (one in Tomsk and Seversk, the other in Moscow) under the guidance ofPVI personnel and the BNL PI. Multiple approaches were pursued, developed, and tested at various locations with the best candidate for commercialization delivered and tested at on an implanter at the PVI client Axcelis. Technical developments were exciting: record output currents of high charge state phosphorus and antimony were achieved; a Calutron-Bemas ion source with a 70% output of boron ion current (compared to 25% in present state-of-the-art). Record steady state output currents of higher charge state phosphorous and antimony and P ions: P{sup 2+} (8.6 pmA), P{sup 3+} (1.9 pmA), and P{sup 4+} (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb{sup 3+} Sb {sup 4 +}, Sb{sup 5+}, and Sb{sup 6+} respectively. Ultimate commercialization goals did not succeed (even though a number of the products like high

  20. Study on the growth of aligned carbon nanotubes controlled by ion bombardment

    International Nuclear Information System (INIS)

    Wang Biben; Zhang Bing; Zheng Kun; Hao Wei; Wang Wanlu; Liao Kejun

    2004-01-01

    Aligned carbon nanotubes were prepared by plasma-enhanced hot filament chemical vapor deposition using CH 4 , H 2 and NH 3 as reaction gases. It was investigated how different negative bias affects the growth of aligned carbon nanotubes. The results indicate that the average diameter of the aligned carbon nanotubes is reduced and the average length of the aligned carbon nanotubes is increased with increasing negative bias. Because of the occurrence of glow discharge, a cathode sheath forms near the substrate surface, and a number of ions are produced in it, and a very strong electrical field builds up near the substrate surface. Under the effect of the field, the strong bombardment of ions on the substrate surface will influence the growth of aligned carbon nanotubes. Combined with related theories, authors have analyzed and discussed the ion bombardment effects on the growth of the aligned carbon nanotudes

  1. Peculiarities of phase transformations in molybdenum-silicon system under ion bombardment

    International Nuclear Information System (INIS)

    Gurskij, L.I.; Zelenin, V.A.; Bobchenok, Yu.L.

    1984-01-01

    The problems of effect of ion bombardment and thermal treatment on the mechanisms of formation of transition layers and structural transformations in the molybdenum-silicon system, where the interface is subjected to ion bombardment through a film of molybdenum, are considered. The method of electron diffraction analysis has been applied to establish that at the molybdenum-silicon interface a transitional region appears during irradiation which has a semiamorphous structure at the doses up to 8x10 14 ion/cm 2 , while at higher doses it transforms into polycrystalline intermediate layer which consists of MoB and the compound close in composition to MoSisub(0.65). Due to thermal treatment for 60873 K a large-grain phase (Mo 3 Si+MoSi 2 ) appears in the transition layer below which a large-grain silicon layer is placed

  2. Investigation of the surface morphology of ion-bombarded biocompatible materials with a SEM and profilograph

    International Nuclear Information System (INIS)

    Kowalski, Z.W.

    1984-01-01

    The surface morphology (topography and roughness) is a very important factor which affects the response of biological tissue to an implant material. The effect of an incident ion beam on surface morphology of various biocompatible materials was studied. All materials were bombarded by Ar + ions at an applied voltage of 7 kV at various incident angles from 0 to 1.4 rad (0 to 80 deg) and at a beam current up to 0.1 mA. The surface topographies of ion-bombarded samples were examined with a Japan Electron Optics Laboratory, model JSM-35, scanning electron microscope. The roughness of the surface was calculated from the shape of a surface profile, which was recorded by a profilograph, the ME 10 (supplied by VEB Carl Zeiss, Jena). (author)

  3. Heavy-ion induced desorption yields of cryogenic surfaces bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Evans, L; Kollmus, H; Küchler, D; Scrivens, R; Severin, D; Wengenroth, M; CERN. Geneva. ATS Department

    2011-01-01

    The ion-induced desorption experiment, installed in the CERN Heavy-Ion Accelerator LINAC 3, has been used to study the dynamic outgassing of cryogenic surfaces. Two different targets, bare and goldcoated copper, were bombarded under perpendicular impact with 4.2 MeV/u Pb54+ ions. Partial pressure rises of H2, CH4, CO, and CO2 and effective desorption yields were measured at 300, 77, and 6.3 K using single shot and continuous ion bombardment techniques. We find that the heavy-ion-induced desorption yield is temperature dependent and investigate the influence of CO gas cryosorbed at 6.3 K. The gain in desorption yield reduction at cryogenic temperature vanishes after several monolayers of CO are cryosorbed on both targets. In this paper we describe the new cryogenic target assembly, the temperature-dependent pressure rise, desorption yield, and gas adsorption measurements.

  4. XPS study of vanadium surface oxidation by oxygen ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Alov, N.; Kutsko, D.; Spirovová, Ilona; Bastl, Zdeněk

    2006-01-01

    Roč. 600, č. 8 (2006), s. 1628-1631 ISSN 0039-6028 R&D Projects: GA ČR GA104/04/0467 Institutional research plan: CEZ:AV0Z40400503 Keywords : vanadium oxide * oxide film * ion-beam oxidation * X-ray photoelectron spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.880, year: 2006

  5. Modification of metallic surfaces by positive ion bombardment

    International Nuclear Information System (INIS)

    Rickards C, J.

    1989-01-01

    Reported are the fundamentals and recent advances in the use of ion implantation techniques and gaseous emissions to modify metal surfaces. The physical phenomena involved, the necessary equipment and some applications which have been successful on an industrial scale are described. (Author). 13 refs, 1 fig

  6. Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD.

    Science.gov (United States)

    Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

    2017-11-24

    In order to confirm the key role of Ar + ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar + ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar + ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar + ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar + ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar + ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar + ion state. As for vertically oriented few-layer graphene (VFG), Ar + ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar + ion bombardment, and these special NCMs are promising in many fields.

  7. Confirming the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials by PECVD

    Science.gov (United States)

    Liu, Yulin; Lin, Jinghuang; Jia, Henan; Chen, Shulin; Qi, Junlei; Qu, Chaoqun; Cao, Jian; Feng, Jicai; Fei, Weidong

    2017-11-01

    In order to confirm the key role of Ar+ ion bombardment in the growth feature of nanostructured carbon materials (NCMs), here we report a novel strategy to create different Ar+ ion states in situ in plasma enhanced chemical vapor deposition (PECVD) by separating catalyst film from the substrate. Different bombardment environments on either side of the catalyst film were created simultaneously to achieve multi-layered structural NCMs. Results showed that Ar+ ion bombardment is crucial and complex for the growth of NCMs. Firstly, Ar+ ion bombardment has both positive and negative effects on carbon nanotubes (CNTs). On one hand, Ar+ ions can break up the graphic structure of CNTs and suppress thin CNT nucleation and growth. On the other hand, Ar+ ion bombardment can remove redundant carbon layers on the surface of large catalyst particles which is essential for thick CNTs. As a result, the diameter of the CNTs depends on the Ar+ ion state. As for vertically oriented few-layer graphene (VFG), Ar+ ions are essential and can even convert the CNTs into VFG. Therefore, by combining with the catalyst separation method, specific or multi-layered structural NCMs can be obtained by PECVD only by changing the intensity of Ar+ ion bombardment, and these special NCMs are promising in many fields.

  8. Structural and magnetic properties of ion-beam bombarded Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.W.; Guo, J.Y.; Lin, S.R.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402 (China); Tsai, C.J. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300 (China); Van Lierop, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg (Canada); Phuoc, N.N.; Suzuki, T. [Information Storage Materials Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan)

    2007-12-15

    A series of [Pt(2 nm)/Co(2 nm)]{sub 10}/Pt(30 nm) multilayers were deposited by using an ion-beam technique. X-ray diffraction and transmission electron microscopy results have shown that as-deposited samples consist of h.c.p. Co and f.c.c. Pt phases. Disordered CoPt{sub 3} phases were developed with increasing End-Hall voltage (V{sub EH}) that induces greater ion-beam bombardment energy during deposition. This indicates that intermixing of Co and Pt increases with ion-beam bombardment. The coercivities (ranging from 100 Oe to 300 Oe) of Co/Pt multilayers decreased with increasing V{sub EH}. After annealing, the formation of CoPt{sub 3} was observed in these ion-beam bombarded samples, resulting in lower coercivities (H{sub c}{proportional_to} 50 Oe). The depressed transition temperature of CoPt{sub 3} for films deposited with the largest V{sub EH} was attributed to distorted CoPt{sub 3} structures that appeared with annealing. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Study of ion-bombardment-induced surface topography of silver by stereophotogrammetric method

    International Nuclear Information System (INIS)

    Fayazov, I.M.; Sokolov, V.N.

    1992-01-01

    The ion-bombardment-induced surface topography of polycrystalline silver was studied using the stereophotogrammetric method. The samples were irradiated with 30keV argon ions at fairly high fluences (> 10 17 ions/cm 2 ). The influence of the inclination angle of the sample in the SEM on the cone shape of a SEM-picture is discussed. To analyse the irradiated surfaces covered with cones, the SEM-stereotechnique is proposed. The measurements of the sample section perpendicular to the incidence plane are also carried out. (author)

  10. Angular and energy dependence of ion bombardment of Mo/Si multilayers

    DEFF Research Database (Denmark)

    Voorma, H.J.; Louis, E.; Bijkerk, F.

    1997-01-01

    The process of ion bombardment is investigated for the fabrication of Mo/Si multilayer x-ray mirrors using e-beam evaporation. The ion treatment is applied immediately after deposition of each of the Si layers to smoothen the layers by removing an additional thickness of the Si layer. In this stu......, the angular dependence of the etch yield, obtained from the in situ reflectivity measurements, is investigated in order o determine the optimal ion beam parameters for the production of multilayer mirrors on curved substrates....

  11. Additional ion bombardment in PVD processes generated by a superimposed pulse bias voltage

    International Nuclear Information System (INIS)

    Olbrich, W.; Kampschulte, G.

    1993-01-01

    The superimposed pulse bias voltage is a tool to apply an additional ion bombardment during deposition in physical vapour deposition (PVD) processes. It is generated by the combination of a d.c. ground voltage and a higher d.c. pulse voltage. Using a superimposed pulse bias voltage in ion-assisted PVD processes effects an additional all-around ion bombardment on the surface with ions of higher energy. Both metal and reactive or inert-gas ions are accelerated to the surface. The basic principles and important characteristics of this newly developed process such as ion fluxes or deposition rates are shown. Because of pulsing the high voltage, the deposition temperature does not increase much. The adhesion, structure, morphology and internal stresses are influenced by these additional ion impacts. The columnar growth of the deposited films could be suppressed by using the superimposed pulse bias voltage without increasing the deposition temperature. Different metallizations (Cr and Cu) produced by arc and sputter ion plating are investigated. Carbon-fibre-reinforced epoxy are coated with PVD copper films for further treatment in electrochemical processes. (orig.)

  12. Low energy Ar ion bombardment damage of Si, GaAs, and InP surfaces

    International Nuclear Information System (INIS)

    Williams, R.S.

    1982-01-01

    Argon bombardment damage to (100) surfaces of Si, GaAs, and InP for sputter ion-gun potentials of 1, 2, and 3 kilovolts was studied using Rutherford backscattering. Initial damage rates and saturation damage levels were determined. Bombardment damage sensitivity increased for the sequence Si, GaAs, and InP. Saturation damage levels for Si and GaAs correspond reasonably to LSS projected range plus standard deviation estimates; damage to InP exceeded this level significantly. For an ion-gun potential of 3 keV, the initial sputter yield of P from an InP surface exceeded the sputter yield of In by four atoms per incident Ar projectile. (author)

  13. Composition and structure of ion-bombardment-induced growth cones on InP

    International Nuclear Information System (INIS)

    Malherbe, J.B.; Lakner, H.; Gries, W.H.

    1991-01-01

    The previously reported effect of low-energy (several keV) ion bombardment on the surface topography of InP was investigated by scanning transmission electron microscopy. Convergent beam electron diffraction patterns of the surface growth 'cones' induced by argon ion bombardment of (100) InP between 7 and 10 keV proved the cones to consist of crystalline InP (and not metallic indium, as has sometimes been claimed). The investigation showed that the irradiated surface region is not rendered completely amorphous but that it recrystallizes from the crystalline/amorphous interface in a columnar growth pattern, often terminating in growth cones protruding above the surface. Weak beam investigations revealed that the overwhelming majority of the cones have the orientation of the substrate. These phenomena were observed at all dose densities from 7 x 10 15 to 2 x 10 17 cm -2 . (author)

  14. Defect production and annihilation in metals through electronic excitation by energetic heavy ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwase, Akihiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    Defect production, radiation annealing and defect recovery are studied in Ni and Cu irradiated with low-energy ({approx}1-MeV) and high-energy ({approx}100-MeV) ions. Irradiation of Ni with {approx}100-MeV ions causes an anomalous reduction, or even a complete disappearance of the stage-I recovery. This result shows that the energy transferred from excited electrons to lattice atoms through the electron-lattice interaction contributes to the annihilation of the stage-I interstitials. This effect is also observed in Ni as a large radiation annealing during 100-MeV heavy ion irradiation. On the other hand, in Cu thin foils, we find the defect production process strongly associated with electron excitation, where the defect production cross section is nearly proportional to S{sub e}{sup 2}. (author)

  15. Engineering catalytic activity via ion beam bombardment of catalyst supports for vertically aligned carbon nanotube growth

    Science.gov (United States)

    Islam, A. E.; Nikolaev, P.; Amama, P. B.; Zakharov, D.; Sargent, G.; Saber, S.; Huffman, D.; Erford, M.; Semiatin, S. L.; Stach, E. A.; Maruyama, B.

    2015-09-01

    Carbon nanotube growth depends on the catalytic activity of metal nanoparticles on alumina or silica supports. The control on catalytic activity is generally achieved by variations in water concentration, carbon feed, and sample placement on a few types of alumina or silica catalyst supports obtained via thin film deposition. We have recently expanded the choice of catalyst supports by engineering inactive substrates like c-cut sapphire via ion beam bombardment. The deterministic control on the structure and chemistry of catalyst supports obtained by tuning the degree of beam-induced damage have enabled better regulation of the activity of Fe catalysts only in the ion beam bombarded areas and hence enabled controllable super growth of carbon nanotubes. A wide range of surface characterization techniques were used to monitor the catalytically active surface engineered via ion beam bombardment. The proposed method offers a versatile way to control carbon nanotube growth in patterned areas and also enhances the current understanding of the growth process. With the right choice of water concentration, carbon feed and sample placement, engineered catalyst supports may extend the carbon nanotube growth yield to a level that is even higher than the ones reported here, and thus offers promising applications of carbon nanotubes in electronics, heat exchanger, and energy storage.

  16. Large area smoothing of surfaces by ion bombardment: fundamentals and applications

    International Nuclear Information System (INIS)

    Frost, F; Fechner, R; Ziberi, B; Voellner, J; Flamm, D; Schindler, A

    2009-01-01

    Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length scales and for the preparation of ultrasmooth surfaces, as an alternative to nanostructuring of various surfaces via self-organization. This requires that in the evolution of the surface topography different relaxation mechanisms dominate over the roughening, and smoothing of initially rough surfaces can occur. This contribution focuses on the basic mechanisms as well as potential applications of surface smoothing using low energy ion beams. In the first part, the fundamentals for the smoothing of III/V semiconductors, Si and quartz glass surfaces using low energy ion beams (ion energy: ≤2000 eV) are reviewed using examples. The topography evolution of these surfaces with respect to different process parameters (ion energy, ion incidence angle, erosion time, sample rotation) has been investigated. On the basis of the time evolution of different roughness parameters, the relevant surface relaxation mechanisms responsible for surface smoothing are discussed. In this context, physical constraints as regards the effectiveness of surface smoothing by direct ion bombardment will also be addressed and furthermore ion beam assisted smoothing techniques are introduced. In the second application-orientated part, recent technological developments related to ion beam assisted smoothing of optically relevant surfaces are summarized. It will be demonstrated that smoothing by direct ion bombardment in combination with the use of sacrificial smoothing layers and the utilization of appropriate broad beam ion sources enables the polishing of various technologically important surfaces down to 0.1 nm root mean square roughness level, showing great promise for large area surface processing. Specific examples are given for ion beam smoothing of different optical surfaces, especially for substrates used for advanced optical applications (e.g., in x-ray optics and components for extreme

  17. Determination of neutron spectra formed by 40-MeV deuteron bombardment of a lithium target with multi-foil activation technique

    CERN Document Server

    Maekawa, F; Wada, M; Wilson, P P H; Ikeda, Y

    2000-01-01

    Neutron flux spectra at an irradiation field produced by a 40-MeV deuteron bombardment on a thick lithium-target at Forschungszentrum Karlsruhe, Germany, have been determined by the multi-foil activation technique. Twenty-seven dosimetry reactions having a wide energy range of threshold energies up to 38 MeV were employed as detectors for the neutron flux spectra extending to 55 MeV. The spectra were adjusted with the SAND-II code with the experimental reaction rates based on an iterative method. The adjusted spectra validated quantitatively the Monte Carlo deuteron-lithium (d-Li) neutron source model code (M sup C DeLi) which was used to calculate initial guess spectra and also has been used for IFMIF nuclear designs. Accuracy of the adjusted spectra was approx 10% that was suitable for successive integral tests of activation cross section data.

  18. Investigation of energy thresholds of atomic and cluster sputtering of some elements under ion bombardment

    CERN Document Server

    Atabaev, B G; Lifanova, L F

    2002-01-01

    Threshold energies of sputtering of negative cluster ions from the Si(111) surface were measured at bombardment by Cs sup + , Rb sup + , and Na sup + ions with energy of 0.1-3.0 keV. These results are compared with the calculations of the similar thresholds by Bohdansky etc. formulas (3) for clusters Si sub n sup - and Cu sub n sup - with n=(1-5) and also for B, C, Al, Si, Fe, Cu atoms. Threshold energies of sputtering for the above elements were also estimated using the data from (5). Satisfactory agreement between the experimental and theoretical results was obtained. (author)

  19. The crystalline-to-amorphous transition in ion-bombarded silicon

    International Nuclear Information System (INIS)

    Mueller, G.; Kalbitzer, S.

    1980-01-01

    Hydrogen-free, but defect-rich a-Si can be obtained by ion bombardment of c-Si. The formation of such material has been studied in detail using carrier-removal measurements in the characterization of the bombardment damage. In order to develop an overall view of the disordering process these data are discussed together with results obtained on similar films by Rutherford back-scattering, electron spin resonance, electron microscopy and optical measurements. It is concluded that amorphous material generally evolves from an intermediate crystalline phase supersaturated with point defects. The transition occurs locally at the sites of energetic ion impacts into critically predamaged crystalline material. As a consequence, an amorphous layer is built up from small clusters with dimensions typically of the order of 50 A. From the net expansion of the bombarded layers it is concluded that regions of lower atomic density are locally present, very likely a consequence of a structural mismatch between individual amorphous clusters. In this way a heterogeneous defect structure may build up in these films which determines their electronic properties. (author)

  20. A model for the build-up of disordered material in ion bombarded Si

    International Nuclear Information System (INIS)

    Nelson, R.S.

    1977-01-01

    A new model based on experimental observation is developed for the build-up of disordered material in ion bombarded silicon. The model assumes that disordered zones are created in a background of migrating point defects, these zones then act as neutral sinks for such defects which interact with the zones and cause recrystallization. A simple steady state rate theory is developed to describe the build-up of disordered material with ion dose as a function of temperature. In general the theory predicts two distinct behaviour patterns depending on the temperature and the ion mass, namely a linear build-up with dose to complete disorder for heavy bombarding ions and a build-up to saturation at a relatively low level for light ions such as protons. However, in some special circumstances a transition region is predicted where the build-up of disorder approximately follows a (dose)sup(1/2) relationship before reverting to a linear behaviour at high dose. (author)

  1. Ion bombardment induced topography evolution on low index crystal surfaces of Cu and Pb

    International Nuclear Information System (INIS)

    Tanovic, L.; Tanovic, N.; Carter, G.; Nobes, M.J.

    1993-01-01

    (100), (110) and (111) oriented single crystal surfaces of Cu and Pb have been bombarded with inert gas ions, self ions, ions of the other substrate species and Bi in the energy range 50-150 keV and in the fluence range 10 15 -10 18 ions.cm 2 . The evolving surface topography was observed by scanning electron microscopy. This topography was observed to be strongly influenced by ion species and surface orientation but the habit of the topography was delineated at low fluences and the features increased in size and density with increasing fluence with some mutation to the more stable of the features. As an example Bi and Pb bombardment of (100) Cu leads to little topographic evolution, (110) Cu develops a system of parallel ridges with (100) facets and (111) Cu develops a prismatic surface, each prism possessing (100) facets. These, and the more general, results cannot be explained by surface erosion by sputtering theory alone (this predicts surface stability of the lowest sputtering yield orientation (110), nor by surface free energy density minimisation criteria (this predicts stability of (111) surfaces). It is proposed that the observed topography is most strongly related to the crystallographic form of precipitates of implanted species. (orig.)

  2. High-energy particle emission from galena and pyrite bombarded with Cs and O ions

    International Nuclear Information System (INIS)

    Karpuzov, D.S.; McIntyre, N.S.

    2002-01-01

    The ejection of energetic particles during steady-state ion surface bombardment has been investigated by means of a dynamic computer simulation as well as in a secondary ion mass spectrometry (SIMS)/low-energy ion scattering from surfaces (LEIS) experiment. The emphasis of this comparative study is on the mass dependence of high-energy tails in sputtering and backscattering for the bombardment of galena (PbS) and pyrite (FeS 2 ) with keV energy ion beam of cesium and oxygen. In the experiment, kinetic energy distributions of sputtered secondary ions (S + , Fe + , Pb + , S - ), as well as backscattered or re-sputtered primary ions (Cs + , O + , O - ), have been measured on a modified Cameca IMS-3f magnetic sector mass spectrometer for keV cesium (Cs + ) and oxygen (O 2 + , O - ) bombardment of galena and pyrite. Ejection of high-energy particles, with emission energies of up to ∼40% or up to ∼60% of the bombarding energy for sputtering of the lighter component (S ± ) with cesium or oxygen, respectively, and of up to ∼40% (Cs + ) and ∼80% (O ± ) for backscattering, has been observed for PbS. The computer simulations were based on the well-known MARLOWE code. In order to model the change of the stoichiometry of the binary compounds, dynamic modification of the target composition in the near-surface region was introduced. Cs incorporation was included, and a relative enrichment of the metallic component (Pb, Fe) in the top few layers due to preferential sputtering of sulfur was allowed. The computer simulations provide information on the formation of altered layer under sputter equilibrium as well as on the energy and angular emission distributions of sputtered and backscattered particles in steady-state conditions. Multiple scattering of Cs projectiles and dynamic re-sputtering of cesium that was previously incorporated in the altered near-surface region can be distinguished in the simulation, and matched with the experimental observations. In addition

  3. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10{sup 15} to 10{sup 16} ions/cm{sup 2}. The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  4. Low-energy ion beam bombardment effect on the plant-cell-envelope mimetic membrane for DNA transfer

    International Nuclear Information System (INIS)

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

    2012-01-01

    This study is a systematic analysis of the mechanisms involved in ion-beam induced DNA transfer, an important application of ion beam biotechnology. Cellulose membranes were used to mimic the plant cell envelope. Ion beams of argon (Ar) or nitrogen (N) at an energy of 25 keV bombarded the cellulose membranes at fluences ranging from 10 15 to 10 16 ions/cm 2 . The damage to the ion-beam-bombarded membranes was characterized using infrared spectroscopy, a micro tensile test and scanning electron microscopy (SEM). Chain scission was the dominant radiation damage type in the membrane. DNA diffusion across the membrane was significantly increased after ion beam bombardment. The increase in DNA transfer is therefore attributed to chain scission, which increases the permeability by increasing the number of pores in the membrane.

  5. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu [Accelerator Engineering Corporation, Chiba (Japan)

    2001-11-19

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  6. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    International Nuclear Information System (INIS)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki; Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu

    2001-01-01

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  7. Low temperature magnetron sputter deposition of polycrystalline silicon thin films using high flux ion bombardment

    International Nuclear Information System (INIS)

    Gerbi, Jennifer E.; Abelson, John R.

    2007-01-01

    We demonstrate that the microstructure of polycrystalline silicon thin films depends strongly on the flux of low energy ions that bombard the growth surface during magnetron sputter deposition. The deposition system is equipped with external electromagnetic coils which, through the unbalanced magnetron effect, provide direct control of the ion flux independent of the ion energy. We report the influence of low energy ( + on the low temperature ( + ions to silicon neutrals (J + /J 0 ) during growth by an order of magnitude (from 3 to 30) enables the direct nucleation of polycrystalline Si on glass and SiO 2 coated Si at temperatures below 400 degree sign C. We discuss possible mechanisms for this enhancement of crystalline microstructure, including the roles of enhanced adatom mobility and the formation of shallow, mobile defects

  8. Topography development on selected inert gas and self-ion bombarded Si

    International Nuclear Information System (INIS)

    Vishnyakov, V.; Carter, G.; Goddard, D.T.; Nobes, M.J.

    1995-01-01

    An AFM and SEM study of the topography induced by 20 keV Si + , Ar + and Xe + ion bombardment of Si at 45 o incidence angles and for ion fluences between 10 17 and 10 20 cm -2 has been undertaken at room temperature. All species generate an atomic scale random roughness, the magnitude of which does not increase extensively with ion fluence, suggesting the operation of a local relaxation process. This nanometre scale roughness forms, for Ar and Xe, a background for coarser micrometre scale structures such as pits, chevrons and waves. Apart from isolated etch pits Si + irradiation generates no repetitive micrometre scale structures. Xe + irradiation produces well developed transverse waves while Ar + irradiation results in isolated chevron-like etch pit trains and ripple patches. This latter pattern evolves, with increasing ion fluence, to a corrugated facet structure. The reasons for the different behaviours are still not fully clarified. (author)

  9. Ion Back-Bombardment of GaAs Photocathodes Inside DC High Voltage Electron Guns

    CERN Document Server

    Grames, Joseph M; Brittian, Joshua; Charles, Daniel; Clark, Jim; Hansknecht, John; Lynn Stutzman, Marcy; Poelker, Matthew; Surles-Law, Kenneth E

    2005-01-01

    The primary limitation for sustained high quantum efficiency operation of GaAs photocathodes inside DC high voltage electron guns is ion back-bombardment of the photocathode. This process results from ionization of residual gas within the cathode/anode gap by the extracted electron beam, which is subsequently accelerated backwards to the photocathode. The damage mechanism is believed to be either destruction of the negative electron affinity condition at the surface of the photocathode or damage to the crystal structure by implantation of the bombarding ions. This work characterizes ion formation within the anode/cathode gap for gas species typical of UHV vacuum chambers (i.e., hydrogen, carbon monoxide and methane). Calculations and simulations are performed to determine the ion trajectories and stopping distance within the photocathode material. The results of the simulations are compared with test results obtained using a 100 keV DC high voltage GaAs photoemission gun and beamline at currents up to 10 mA D...

  10. On the modification of metal/ceramic interfaces by low energy ion/atom bombardment during film growth

    International Nuclear Information System (INIS)

    Rigsbee, J.M.; Scott, P.A.; Knipe, R.K.; Hock, V.F.

    1986-01-01

    Elemental Cu and Ti films have been deposited onto ceramic substrates with a plasma-aided physical vapor deposition (ion-plating) process. This paper discusses how the structure and chemistry of the metallic film and the metal/ceramic interface are modified by low energy ion and neutral atom bombardment. Emphasis is placed on determining how low energy ion/neutral atom bombardment affects the strength of the metal/ceramic interface. Analyses of the film, interface and substrate regions have employed scanning Auger microprobe, secondary ion mass spectroscopy, SEM/STEM-energy dispersive X-ray and TEM/STEM imaging and microdiffraction techniques. (Auth.)

  11. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  12. Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

    Energy Technology Data Exchange (ETDEWEB)

    Schmalhorst, Jan; Reiss, Guenter; Hoenik, V. [Thin Films and Nanostructures, Department of Physics, Univ. Bielefeld (Germany); Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology, Kassel Univ. (Germany)

    2007-07-01

    Artificial ferrimagnets (AFi) have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment induced magnetic patterning with He ions on a single layer reference electrode of magnetic tunnel junctions is possible. For some applications a combination of ion bombardment induced magnetic patterning and artificial ferrimagnets as a reference electrode is desirable. The effect of ion bombardment induced magnetic patterning on pinned artificial ferrimagnets with a Ru interlayer which is frequently used in magnetic tunnel junctions as well as pinned AFis with a Cu interlayer has been tested. Special attention has been given to the question whether the antiferromagnetic interlayer exchange coupling can withstand the ion dose necessary to turn the exchange bias.

  13. Low-energy ion bombardment of frozen bacterial spores and its relevance to interplanetary space

    International Nuclear Information System (INIS)

    Tuleta, M.; Gabla, L.; Szkarlat, A.

    2005-01-01

    The panspermia hypothesis is concerned with the dissemination of life in space in the form of simple micro-organisms. During an interplanetary journey the micro-organisms are subjected to the action of, among others, the solar wind. We have simulated experimentally such conditions bombarding frozen bacterial spores with low-energy hydrogen ions. On the basis of the results obtained and our earlier research, a new look at the panspermia hypothesis is discussed. The general conclusion is that unprotected naked spores, their conglomerates and protected spores can survive attack of the solar wind, although to various degrees. (authors)

  14. A theoretical approach to sputtering due to molecular ion bombardment, 1

    International Nuclear Information System (INIS)

    Karashima, Shosuke; Ootoshi, Tsukuru; Kamiyama, Masahide; Kim, Pil-Hyon; Namba, Susumu.

    1981-01-01

    A shock wave model is proposed to explain theoretically the non-linear effects in sputtering phenomena by molecular ion bombardments. In this theory the sputtering processes are separated into two parts; one is due to linear effects and another is due to non-linear effects. The treatment of the linear parts is based on the statistical model by Schwarz and Helms concerning a broad range of atomic collision cascades. The non-linear parts are treated by the model of shock wave due to overlapping cascades, and useful equations to calculate the sputtering yields and the dynamical quantities in the system are derived. (author)

  15. Low-energy ion bombardment of frozen bacterial spores and its relevance to interplanetary space

    Energy Technology Data Exchange (ETDEWEB)

    Tuleta, M.; Gabla, L. [Jagiellonian Univ., Institute of Physics, Cracow (Poland); Szkarlat, A. [Clinical Children' s Hospital of the Jagiellonian Univ., Medical College, Lab. of Microbiology, Cracow (Poland)

    2005-04-01

    The panspermia hypothesis is concerned with the dissemination of life in space in the form of simple micro-organisms. During an interplanetary journey the micro-organisms are subjected to the action of, among others, the solar wind. We have simulated experimentally such conditions bombarding frozen bacterial spores with low-energy hydrogen ions. On the basis of the results obtained and our earlier research, a new look at the panspermia hypothesis is discussed. The general conclusion is that unprotected naked spores, their conglomerates and protected spores can survive attack of the solar wind, although to various degrees. (authors)

  16. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  17. A liquid-like model for the morphology evolution of ion bombarded thin films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, L., E-mail: luca.repetto@unige.it [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Lo Savio, R. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, B. [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, G.; Angeli, E.; Valbusa, U. [Department of Physics and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2015-07-01

    Thin solid films exposed to ion irradiation exhibit a peculiar evolution that can differ substantially from what is observed for bulk samples. The phenomenology of the patterns that self-organize on the substrate is very rich, with morphologies that display several degrees of order upon the modification of initial film characteristics and irradiation parameters. This richness paves the way for the fabrication of novel functional surfaces, but it is also an indication of the complexity of the underlying driving mechanisms. A remarkable simplification for the comprehension of these phenomena can come from the noteworthy similarity of the obtained patterns with those showing up when liquids dewet from their substrates. Here, we analyze the possibility to apply a liquid-like model to explain the morphology evolution of ion bombarded thin films for the whole phenomenology showing up in experiments. In establishing this connection between liquids and ion bombarded thin films, we propose to use also for liquids the insight gained for our system with recent experiments that stress the importance of the substrate topography for the selection of the dewetting mechanism. If confirmed, this result would lead to a reconsideration of the importance of capillary waves in spinodal dewetting, and will help to understand the low reproducibility of the related experimental results.

  18. Conical surface textures formed by ion bombarding 2% Be-Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1991-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form depend strongly on argon energy (from 250 to 1500 eV); argon fluence (10 19 to 10 20 ions cm -2 ); and argon flux (0.1 to 1 mA cm -2 ). The texture morphology depends less strongly on the background ambient (Mo versus graphite), earlier alloy heat treatments and the temperature during bombardment (100 o C and 450 o C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical side-wall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including pulsed power Li + beam anodes; cold cathode field emission devices; optical absorbers and catalysis supports. (author)

  19. Suppression secondary electrons from target surface under pulsed ion beams bombardment

    International Nuclear Information System (INIS)

    Yang Zhen; Peng Yufei; Long Jidong; Lan Chaohui; Dong Pan; Shi Jinshui

    2012-01-01

    The producing mechanism of secondary electrons from target surface under ion beams bombardment is discussed. Several methods to suppress the secondary electrons in special vacuum devices and their advantages and disadvantages are introduced. The ways of using self-bias and curved surface target are proposed and verified in the experiment. The results show that the secondary electrons can be effectively suppressed when the self-bias is larger than 80 V. The secondary electron yield decreases by using curved surface target instead of flat target. The secondary electron yield calculated from the experimental data is about 0.67, which is slightly larger than the value (0.58) from the literature due to the impurities of the ion beam and target surface. The effect of suppressing the electron countercurrent by the self-bias method is analyzed. The result shows that the self-bias method can not only suppress the secondary electrons from target surface under ion beams bombardment, but also suppress the electron countercurrent resulting from the instability of the pulsed power source. (authors)

  20. Conical surface textures formed by ion bombarding 2% Be Cu alloy

    International Nuclear Information System (INIS)

    Panitz, J.K.G.

    1990-01-01

    A homogeneous, micrometer-sized conical surface texture forms on 2% Be-Cu alloy which is bombarded with an argon beam produced by a Kaufman ion source. The dimensions of the features that form strongly depend on: (1) argon energy (from 250 to 1500 eV), (2) fluence (10 19 to 10 20 ions/cm 2 ), and (3) flux (0.1 to 1 mA/cm 2 ). The texture morphology depends less strongly on the background ambient (Mo vs graphite), earlier alloy heat treatments and the temperature during bombardment (100 degree C and 450 degree C). As the texture matures with increasing fluence, the number of large features increases at the expense of the number of small features. The observed relationship between texture formation and ion flux suggests that the evolution of these features is not adequately described by theories predicting that the mature conical sidewall angle is related to the angle of the maximum sputtering yield. These textured surfaces can be coated with other metals for a variety of possible applications including: (1) pulsed power Li+ beam anodes, (2) cold cathode field emission devices, (3) optical absorbers and (4) catalysis supports. 18 refs., 5 figs

  1. Ion induced electron emission statistics under Agm- cluster bombardment of Ag

    Science.gov (United States)

    Breuers, A.; Penning, R.; Wucher, A.

    2018-05-01

    The electron emission from a polycrystalline silver surface under bombardment with Agm- cluster ions (m = 1, 2, 3) is investigated in terms of ion induced kinetic excitation. The electron yield γ is determined directly by a current measurement method on the one hand and implicitly by the analysis of the electron emission statistics on the other hand. Successful measurements of the electron emission spectra ensure a deeper understanding of the ion induced kinetic electron emission process, with particular emphasis on the effect of the projectile cluster size to the yield as well as to emission statistics. The results allow a quantitative comparison to computer simulations performed for silver atoms and clusters impinging onto a silver surface.

  2. 0,01-5 MeV heavy ion accelerators

    International Nuclear Information System (INIS)

    Golubev, V.P.; Ivanov, A.S.; Nikiforov, S.A.; Svin'in, M.P.; Tarvid, G.V.; Troshikhin, A.G.; Fedotov, M.T.

    1983-01-01

    The results of development of an accelerating complex on the base of the UP-2-1 heavy ion charge exchange accelerator and IMPLANT-500 high-voltage heavy ion accelerator are given. The accelerating complex provides overlapping of the 0.01 MeV to 5 MeV energy range at accelerated beam currents of 10 -3 -10 -6 A order. The structural features of accelerators and their basic units and systems are considered. The UP-2-1 accelerator is designed for researches in the field of experimental physics and applied problem solutions. The IMPLANT-500 accelerator is designed for commercial ion-beam facilities with closed loop of silicon plate treatment

  3. The influence of noble-gas ion bombardment on the electrical and optical properties of clean silicon surfaces

    International Nuclear Information System (INIS)

    Martens, J.W.D.

    1980-01-01

    A study of the effect of argon and helium ion bombardment on the electrical and optical properties of the clean silicon (211) surface is described. The objective of the study was to determine the effect of noble gas ions on the density of surface states at the clean silicon surface. (Auth.)

  4. The effects of argon ion bombardment on the corrosion resistance of tantalum

    Science.gov (United States)

    Ramezani, A. H.; Sari, A. H.; Shokouhy, A.

    2017-02-01

    Application of ion beam has been widely used as a surface modification method to improve surface properties. This paper investigates the effect of argon ion implantation on surface structure as well as resistance against tantalum corrosion. In this experiment, argon ions with energy of 30 keV and in doses of 1 × 1017-10 × 1017 ions/cm2 were used. The surface bombardment with inert gases mainly produces modified topography and morphology of the surface. Atomic Force Microscopy was also used to patterned the roughness variations prior to and after the implantation phase. Additionally, the corrosion investigation apparatus wear was applied to compare resistance against tantalum corrosion both before and after ion implantation. The results show that argon ion implantation has a substantial impact on increasing resistance against tantalum corrosion. After the corrosion test, scanning electron microscopy (SEM) analyzed the samples' surface morphologies. In addition, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. The purpose of this paper was to obtain the perfect condition for the formation of tantalum corrosion resistance. In order to evaluate the effect of the ion implantation on the corrosion behavior, potentiodynamic tests were performed. The results show that the corrosion resistance of the samples strongly depends on the implantation doses.

  5. Self-organised nano-structuring of thin oxide-films under swift heavy ion bombardment

    International Nuclear Information System (INIS)

    Bolse, Wolfgang

    2006-01-01

    Surface instabilities and the resulting self-organisation processes play an important role in nano-technology since they allow for large-array nano-structuring. We have recently found that the occurrence of such instabilities in thin film systems can be triggered by energetic ion bombardment and the subsequent self-assembly of the surface can be nicely controlled by fine-tuning of the irradiation conditions. The role of the ion in such processes is of double nature: If the instability is latently present already in the virgin sample, but self-assembly cannot take place because of kinetic barriers, the ion impact may just supply the necessary atomic mobility. On the other hand, the surface may become instable due to the ion beam induced material modifications and further irradiation then results in its reorganisation. In the present paper, we will review recently observed nano-scale self-organisation processes in thin oxide-films induced by the irradiation with swift heavy ions (SHI) at some MeV/amu energies. The first example is about SHI induced dewetting, which is driven by capillary forces already present in the as-deposited samples. The achieved dewetting pattern show an amazing similarity to those observed for liquid polymer films on Si, although in the present case the samples were kept at 80 K and hence have never reached their melting point. The second example is about self-organised lamellae formation driven by planar stresses, which are induced by SHI bombardment under grazing incidence and result in a surface instability and anisotropic plastic deformation (hammering effect). Taking advantage of these effects and modifying the irradiation procedure, we were able to generate more complex structures like NiO-'nano-towers' of 2 μm height and 200 nm in diameter

  6. Radiation-induced segregation in light-ion bombarded Ni-8% Si

    International Nuclear Information System (INIS)

    Packan, N.H.; Heatherly, L.; Kesternich, W.; Schroeder, H.

    1986-01-01

    Tensile specimens 60 μm thick of Ni-8 at. % Si have been bombarded at 475 0 C to doses of 0.1 to 0.3 dpa with either 7 MeV proton or 28 MeV alpha particle beams. Deliberate embrittlement by high temperature (700 0 C) preimplantation of helium was required to produce intergranular fracture. Depth profile sputtering and analysis in a Scanning Auger Microprobe was then used to study radiation-induced segregation of silicon both at the external surfaces and at internal interfaces. The external surfaces exhibited a strongly silicon-enriched zone for the first 10 to 20 nm followed by a broad (approx.200 nm), shallow silicon-depleted region. Segregation of silicon to grain boundaries varied from interface to interface and possibly from region to region on a given interface. In general, however, depth profiles of silicon content with distance from internal boundaries showed no noticeable depletion zone and a more gradual fall-off compared to the profiles from external surfaces. The variations of RIS among boundaries and with type of interface probably reflect, at least in part, intrinsic differences in sink efficiency

  7. L-subshell ionization studies in Au and Bi for 19F and 28Si large-ion bombardment

    International Nuclear Information System (INIS)

    Padhi, H.C.; Dhal, B.B.; Nanal, V.; Prasad, K.G.; Tandon, P.N.; Trautmann, D.

    1996-01-01

    L x-ray production and subshell ionization cross sections of Au and Bi have been measured for the bombardment of 19 F and 28 Si ions in the energy range 30 endash 57 MeV and 36 endash 84 MeV, respectively. Comparison of the Lα x-ray production cross sections of Au with the earlier data by Malhi and Gray [Phys. Rev. A 44, 7199 (1991)] shows reasonable agreement for 19 F impact and their data are consistently higher for 28 Si at all energies. The measured Lα line energy shows a shift towards higher energy, which appears to be proportional to the square of the projectile atomic number at all impact energies. This shift suggests the presence of multiple ionization in the L and M shells with a simultaneous production of four M holes in Au at the impact energy of 3 MeVu -1 of 28 Si. The L-subshell ionization cross sections obtained from the measured x-ray production cross sections have been compared with the semiclassical approximation and perturbed stationary state theory with energy loss, Coulomb deflection, and relativistic correction for the electron motion calculations, which show large deviations for the L 1 subshell. The L 2 - and L 3 -subshell ionization cross sections are underestimated by both the theories by a factor of 1.2 endash 4.0 for 28 Si impact whereas for the 19 F case there is reasonable agreement for the L 3 cross section but the L 2 cross section is underestimated by 20 endash 30%. copyright 1996 The American Physical Society

  8. Immediate fabrication of flower-like graphene oxide by ion beam bombardment

    International Nuclear Information System (INIS)

    Cheng, Junjie; Zhang, Yuanyuan; Zhang, Guilong; Xiong, Shiquan; Pei, Renjun; Cai, Dongqing; Wu, Zhengyan

    2015-01-01

    Graphical abstract: - Highlights: • Ion beam bombardment (IBB) could modify the microstructure of graphene oxide (GO). • IBB could transform a compact multi-layered GO to a few-layered flower-like GO. • IBB could effectively improve the dispersion and the related properties of GO. • The main mechanism was proposed to be the etching and charge effects of IBB. - Abstract: An effective and convenient method using ion beam bombardment (IBB) for separating a multi-layered compact graphene oxide (GO) piece into several small few-layered loose pieces was developed, and it was found that those small GO pieces had formed a flower-like structure. Therein, the main mechanism was proposed to be the etching and charge effects of IBB. This work could provide a facile and promising approach for improving the dispersion and the related properties of GO. Furthermore, X-ray diffraction and Raman spectrum determinations demonstrated that, with the increasing fluence, IBB could effectively decrease the chemical groups in the layers of GO, resulting in the decrease of the layer distance.

  9. Immediate fabrication of flower-like graphene oxide by ion beam bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Junjie [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zhang, Yuanyuan; Zhang, Guilong [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Xiong, Shiquan [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Pei, Renjun, E-mail: rjpei2011@sinano.ac.cn [Division of Nanobiomedicine, Key Laboratory for Nano-Bio Interface Research, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Cai, Dongqing, E-mail: dqcai@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Wu, Zhengyan, E-mail: zywu@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-12-01

    Graphical abstract: - Highlights: • Ion beam bombardment (IBB) could modify the microstructure of graphene oxide (GO). • IBB could transform a compact multi-layered GO to a few-layered flower-like GO. • IBB could effectively improve the dispersion and the related properties of GO. • The main mechanism was proposed to be the etching and charge effects of IBB. - Abstract: An effective and convenient method using ion beam bombardment (IBB) for separating a multi-layered compact graphene oxide (GO) piece into several small few-layered loose pieces was developed, and it was found that those small GO pieces had formed a flower-like structure. Therein, the main mechanism was proposed to be the etching and charge effects of IBB. This work could provide a facile and promising approach for improving the dispersion and the related properties of GO. Furthermore, X-ray diffraction and Raman spectrum determinations demonstrated that, with the increasing fluence, IBB could effectively decrease the chemical groups in the layers of GO, resulting in the decrease of the layer distance.

  10. Study and realisation of an ion source obtained by electronic bombardment - experimentation with phosphorus

    International Nuclear Information System (INIS)

    Schneider, Philippe

    1979-01-01

    This research thesis reports the study and development of an ion source by electronic bombardment. In order to solve some practical difficulties (cathode destruction, source instability, and so on), the design of each component has been very careful, notably for the electron gun. The author first briefly discusses the exiting ionisation processes, gives a list of ion which can be produced, with a focus on phosphorus for which the ionisation cross section is defined and assessed. After an assessment of different ionisation processes, and an indication of performance of the best existing sources, the author explains the choice for a totally different process. In the second part, he describes the experimental device, and particularly the electron gun as its design has been an important part of this research work. The source operation is described and its characteristics and performance are studied. Finally, the author outlines that some improvements are still possible to obtain a totally exploitable source [fr

  11. Erosion of volatile elemental condensed gases by keV electron and light-ion bombardment

    International Nuclear Information System (INIS)

    Schou, J.

    1991-11-01

    Erosion of the most volatile elemental gases by keV electron and light-ion bombardment has been studied at the experimental setup at Risoe. The present work includes frozen neon, argon, krypton, nitrogen, oxygen and three hydrogen isotopes, deuterium, hydrogen deuteride and hydrogen. The yield of these condensed gases has been measured as a function of film thickness and primary energy for almost all combinations of primary particles (1-3 keV electrons, 5-10 keV hydrogen- and helium ions) and ices. These and other existing results show that there are substantial common features for the sputtering of frozen elemental gases. Within the two groups, the solid rare gases and the solid molecular gases, the similarity is striking. The hydrogenic solids deviate in some respects from the other elements. The processes that liberate kinetic energy for the particle ejection in sputtering are characteristic of the specific gas. (au) 3 tabs., 12 ills., 159 refs

  12. An ion accelerator facility for the preparation of nuclear bombardement targets

    International Nuclear Information System (INIS)

    Grime, G.W.; Takacs, J.

    1981-01-01

    As a result of the demand for increasingly complex nuclear bombardment targets in this laboratory, work has started on the construction of a medium-energy accelerator facility capable of preparing targets both by ion implantation and by heavy-ion sputtering. Basic consideration was given in the design to flexibility and simplicity. The ion source chosen was the Harwell sputter ion gun which is capable of producing ions of practically any element at currents up to several hundred μA. This was modified to suit our specific requirement. The acceleration system was constructed to operate at a maximum of 100 kV, and the beam is focussed by a three-cylinder electrostatic lens. The ions are analysed by 50 0 magnet which is capable of a mass dispersion of 7 mm in the target chamber between adjacent mass numbers at mass 100. A slit feedback system is used to stabilise the energy against short-term fluctuations. The system is fitted with two target chambers; one after the magnet and one after the electrostatic lens. The latter is used for applications such as sputtering. Two dimensional scanning is available in both target chambers for ensuring uniformity of implantation over areas larger than the spot size. Using this apparatus, implanted targets of 3 He and 20 Ne have been prepared. In addition high quality films of refractory metals have been sputtered using Ar or Xe beams. (orig.)

  13. Differential production cross sections for charged particles produced by 590 MeV proton bombardment of thin metal targets

    International Nuclear Information System (INIS)

    Howe, S.D.; Cierjacks, S.; Hino, Y.; Raupp, F.; Rainbow, M.T.; Swinhoe, M.T.; Buth, L.

    1981-01-01

    Differential production cross sections have been measured for the reactions (p,p), (p,d), (p,t) and (p,π+-) using the 590 MeV proton beam at SIN. Here we report measurements made on thin targets of aluminium, niobium, lead, and uranium at laboratory angles of 90 0 and 157 0 . The data were taken over a proton energy range of about 50 MeV to 590 MeV. Differential cross sections are reported along with predictions by the intranuclear-cascade/evaporation model as computed by HETC. (orig.)

  14. Pion production from deuterium by the bombardment with polarized protons of 277 and 500 MeV

    International Nuclear Information System (INIS)

    Lolos, G.J.; Auld, E.G.; Giles, G.; Jones, G.; McParland, B.; Ottewell, D.; Walden, P.L.; Zeigler, W.

    1982-11-01

    Analyzing power measurements of the (anti) pd → tπ + reaction are reported at incident proton energies of 277 and 500 MeV. The 277 MeV results span the angular range from 70 0 to 130 0 in the centre of mass while the two 500 MeV measurements at large angles were taken as a check of published results. With the angular distribution of the analyzing power at 277 MeV being now available, an examination of the energy dependence of the analyzing power shows that it exhibits characteristics closely resembling the shape and magnitude of the distribution observed for nuclei in the 9-12 mass range

  15. Ion-bombardment effects on the fatigue life of stainless steel under simulated fusion first-wall conditions

    International Nuclear Information System (INIS)

    Kohse, G.E.

    1983-02-01

    An experiment which uses the MITR-II 5 MW research reactor to simulate several aspects of the anticipated environment of a fusion reactor first wall is described. Pressurized tube specimens are subjected simultaneously to stress and temperature cycling, surface bombardment by energetic helium and lithium ions and bulk irradiation by high-energy neutrons. Analysis of the samples is aimed primarily at determining the behavior of the ion bombarded surface layer, which has a depth of 2.5 μm, with particular reference to possible effects on the fatigue life of the material

  16. Recovery of 201Tl by ion exchange chromatography from proton bombarded thallium cyclotron targets

    International Nuclear Information System (INIS)

    Walt, T.N. van der; Naidoo, C.

    2000-01-01

    A method based on ion exchange chromatography is presented for the recovery of 201 Tl and its precursor 201 Pb from proton bombarded natural thallium cyclotron targets. After bombardment the target is dissolved in diluted nitric acid. Water, hydrazine and ammonium acetate are added to the solution and the lead radioisotopes separated from the thallium by cation exchange chromatography on a Bio-Rex 70 column. The sorbed lead radioisotopes are eluted with dilute nitric acid and the separation repeated on a second Bio-Rex 70 column. After elution of the remaining thallium the column is left for 32 hours and the 201 Tl formed by decay of 201 Pb is eluted with an ammonium acetate solution. The 201 Tl eluate is acidified with a HNO 3 -HBr-Br 2 mixture and the resulting solution is passed through an AG MP-1 anion exchanger column to remove any remaining lead isotopes. The 201 Tl is eluted with a hydrazine solution, the eluate evaporated to dryness and the 201 Tl finally dissolved in an appropriate solution to produce a 201 TlCl solution suitable for medical use. A high quality 201 Tl product is obtained containing ≤ 0.1 μg of Tl/mCi (37 MBq) 201 Tl. The radionuclidic impurities are less than the maximum values specified by the US Pharmacopoeia and the British Pharmacopoeia. (orig.)

  17. The development of cones and associated features on ion bombarded copper

    International Nuclear Information System (INIS)

    Whitton, J.L.; Carter, G.; Nobes, M.J.; Williams, J.S.

    1977-01-01

    Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features, have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other features is a pre-requisite to cone generation in high-purity crystalline substrates. We suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either pre-existing or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (author)

  18. The development of cones and associated features on ion bombarded copper

    International Nuclear Information System (INIS)

    Whitton, J.L.; Williams, J.S.

    1977-01-01

    Observations of ion-bombardment-induced surface modifications on crystalline copper substrates have been made using scanning electron microscopy. The delineation and development of grain boundary edges, faceted and terraced etch pits and small-scale ripple structure, together with the formation of faceted conical features have all been observed on low and high purity polycrystalline substrates. In general, the density of such surface morphological features, although variable from grain to grain, is higher in the proximity of grain boundaries. In particular, cones are only found within regions where other surface erosional features are present and it would appear that the development of these other surface features is a pre-requisite to cone generation in high-purity crystalline substrates. The authors suggest the operation of a defect-induced mechanism of cone formation whereby sputter elaboration of bulk defects (either preexisting or bombardment-induced) leads to the formation and development of surface features which, in turn, may intersect and result in the generation of cones. (Auth.)

  19. Photon emission produced by Kr+ ions bombardment of Cr and Cr2O3 targets

    International Nuclear Information System (INIS)

    Boujlaidi, A. El; Hammoum, K.; Jadoual, L.; Jourdani, R.; Ait El Fqih, M.; Aouchiche, H.; Kaddouri, A.

    2015-01-01

    The sputter induced photon spectroscopy technique was used to study the luminescence spectra of the species sputtered from chromium powder and its oxide Cr 2 O 3 , during 5 keV Kr + ions bombardment in vacuum better than 10 −7 torr. The optical spectra recorded between 350 and 470 nm exhibit discrete lines which are attributed to neutral excited atoms of chromium (Cr I lines). The experiments are also performed under 10 −5 torr ultra pure oxygen partial pressure. The results demonstrate that the measured intensities of the emitted photons are always higher in the presence of oxygen and even higher than those obtained for Cr 2 O 3 target. In the presence of oxygen vapor we assume that an oxide film is formed on the chromium surface which is responsible of the increase of photon emission. This variation in the intensities is correctly explained in the model of electron transfer processes between the excited sputtered atom and the bombarded surface. This model suggests that the structure formed on the Cr surface in the case of oxygenated chromium is closer to that of Cr 2 O 3 oxide

  20. Study of the thermal oxidation of titanium and zirconium under argon ion irradiation in the low MeV range (E = 15 MeV)

    International Nuclear Information System (INIS)

    Do, N.-L.

    2012-01-01

    We have shown that argon ion irradiation between 1 and 15 MeV produces damage on both titanium and zirconium surfaces, taking the form of accelerated oxidation and/or craterization effects, varying as a function of the projectile energy and the annealing atmosphere (temperature and pressure) simulating the environmental conditions of the fuel/cladding interface of PWR fuel rods. Using AFM, we have shown that the titanium and zirconium surface is attacked under light argon ion bombardment at high temperature (up to 500 C) in weakly oxidizing medium (under rarefied dry air pressure ranging from 5,7 10 -5 Pa to 5 10 -3 Pa) for a fixed fluence of about 5 10 14 ions.cm -2 . We observed the formation of nano-metric craters over the whole titanium surface irradiated between 2 and 9 MeV and the whole zirconium surface irradiated at 4 MeV, the characteristics of which vary depending on the temperature and the pressure. In the case of the Ar/Ti couple, the superficial damage efficiency increases when the projectile energy decreases from 9 to 2 MeV. Moreover, whereas the titanium surface seems to be transparent under the 15-MeV ion beam, the zirconium surface exhibits numerous micrometric craters surrounded by a wide halo. The crater characteristics (size and superficial density) differ significantly from that observed both in the low energy range (keV) where the energy losses are controlled by ballistic collisions (Sn) and in the high energy range (MeV - GeV) where the energy losses are controlled by electronic excitations (Se), which was not completely unexpected in this intermediate energy range for which combined Sn - Se stopping power effects are possibly foreseen. Using XPS associated to ionic sputtering, we have shown that there is an irradiation effect on thermal oxidation of titanium, enhanced under the argon ion beam between 2 and 9 MeV, and that there is also an energy effect on the oxide thickness and stoichiometry. The study conducted using Spectroscopic

  1. AES, EELS and TRIM simulation method study of InP(100 subjected to Ar+, He+ and H+ ions bombardment.

    Directory of Open Access Journals (Sweden)

    Abidri B.

    2012-06-01

    Full Text Available Auger Electron Spectroscopy (AES and Electron Energy Loss Spectroscopy (EELS have been performed in order to investigate the InP(100 surface subjected to ions bombardment. The InP(100 surface is always contaminated by carbon and oxygen revealed by C-KLL and O-KLL AES spectra recorded just after introduction of the sample in the UHV spectrometer chamber. The usually cleaning process of the surface is the bombardment by argon ions. However, even at low energy of ions beam (300 eV indium clusters and phosphorus vacancies are usually formed on the surface. The aim of our study is to compare the behaviour of the surface when submitted to He+ or H+ ions bombardment. The helium ions accelerated at 500V voltage and for 45 mn allow removing contaminants but induces damaged and no stoichiometric surface. The proton ions were accelerated at low energy of 500 eV to bombard the InP surface at room temperature. The proton ions broke the In-P chemical bonds to induce the formation of In metal islands. Such a chemical reactivity between hydrogen and phosphorus led to form chemical species such as PH and PH3, which desorbed from the surface. The chemical susceptibly and the small size of H+ advantaged their diffusion into bulk. Since the experimental methods alone were not able to give us with accuracy the disturbed depth of the target by these ions. We associate to the AES and EELS spectroscopies, the TRIM (Transport and Range of Ions in Matter simulation method in order to show the mechanism of interaction between Ar+, He+ or H+ ions and InP and determine the disturbed depth of the target by argon, helium or proton ions.

  2. Comparison of 4.2 MeV Fe+ and 46.5 MeV Ni6+ ion irradiation for the study of void swelling

    International Nuclear Information System (INIS)

    Blamires, N.G.; Worth, J.H.

    1975-11-01

    Void formation in pure nickel and 316 steel containing 10 ppm He has been studied using 4.2 MeV Fe+ ions from the Harwell Van de Graaff accelerator. The dose dependence of swelling in nickel at 525degC and the dose and temperature dependence of swelling in 316 steel is reported. The results are compared with those of other workers, especially those sup(13,14) using 46.5 MeV Ni 6+ ions. In general, there is good agment, except for a marked decrease in swelling of 316 steel at 650degC and 700degC compared with the Ni 6+ bombardment. The reason for this is thought to result from the restricted width of the damaged region in the low energy case which at the high temperatures is comparable with the inter-void spacing. Anomalous void distributions adjacent to grain boundaries are reported and are probably caused by grain boundary movement. Denuded zones at grain boundaries in 316 steel vary in width from approximatly 1300A at 450degC to approximatly 8800A at 700degC. The region adjacent to the surface of the nickel specimens exhibits an abnormally high swelling. Possible explanations are suggested

  3. Energy dependence of angular distributions of sputtered particles by ion-beam bombardment at normal incidence

    International Nuclear Information System (INIS)

    Matsuda, Yoshinobu; Ueda, Yasutoshi; Uchino, Kiichiro; Muraoka, Katsunori; Maeda, Mitsuo; Akazaki, Masanori; Yamamura, Yasunori.

    1986-01-01

    The angular distributions of sputtered Fe-atoms were measured using the laser fluorescence technique during Ar-ion bombardment for energies of 0.6, 1, 2 and 3 keV at normal incidence. The measured cosine distribution at 0.6 keV progressively deviated to an over-cosine distribution at higher energies, and at 3 keV the angular distribution was an overcosine distribution of about 20 %. The experimental results agree qualitatively with calculations by a recent computer simulation code, ACAT. The results are explained by the competition between surface scattering and the effects of primary knock-on atoms, which tend to make the angular distributions over-cosine and under-cosine, respectively. (author)

  4. Dependence of ion - photon emission characteristics on the concentration of implanted atoms of the bombarding beam

    International Nuclear Information System (INIS)

    Belykh, S.F.; Evtukhov, R.N.; Redina, I.V.; Ferleger, V.Kh.

    1989-01-01

    Results of experiment, where Dy + beams, its spraying products emitting intensively optical radiation with continuous spectrum (CSR), are used for tantalum surface bombardment, are presented. The given experiment allowed one to separate the scattered particle CSR contribution and was conducted under controlled beam n atom concentration on the target surface. E 0 energy and j 0 dysprosium ion flux density made up respectively 3.5 keV and 3x10 5 Axcm -2 . The obtained result analysis has shown that a notable dependence of spectrum type on n value is detected. Dy scattered atoms to not emit CSR. The main contribution to CSR is made by sprayed particles, containing dysprosium atoms

  5. Damage structure in Nimonic PE16 alloy ion bombarded to high doses and gas levels

    International Nuclear Information System (INIS)

    Farrell, K.; Packan, N.H.

    1981-01-01

    The Nimonic PE16 alloy in solution-treated-and-aged condition was bombarded simultaneously with nickel ions and α and deuteron beams at 625 0 C to doses of 80 to 313 dpa at He/dpa = 10 and D/dpa = 25. Microstructural changes consisted of the introduction of dislocations and of cavities, and the redistribuion of γ' precipitates to these defects. Cavitational swelling remained below 1%. Cavities were represented by several distinct size classes, the smaller ones believed to be gas bubbles, and some larger ones associated with preferred growth of precipitate. Formation of bubbles at grain boundaries, and large cavities at incoherent twins intensified the possibility of mechanical separation of interfaces under high-gas irradiation conditions

  6. Study of clean and ion bombardment damaged silver single crystal surfaces by work function measurements

    International Nuclear Information System (INIS)

    Chelvayohan, N.

    1982-06-01

    Work function values of the (110), (100) and (111) faces of silver single crystal were measured by the photoelectric emission method and found to be 4.14 +- 0.04 eV, 4.22 +-0.04 eV and 4.46 +- 0.02 eV respectively. Oxygen adsorption on the faces were studied by surface potential measurement. Strong oxygen adsorption was observed on (110) and (100) faces, whereas the (111) face was found to be inert for oxygen adsorption. Oxygen adsorption on the (111) face damaged by argon ion bombardment was also investigated. The above results were compared with those of early reported work function and oxygen adsorption values. (U.K.)

  7. Silicon nanodot formation and self-ordering under bombardment with heavy Bi3 ions

    International Nuclear Information System (INIS)

    Boettger, Roman; Heinig, Karl-Heinz; Bischoff, Lothar; Liedke, Bartosz; Huebner, Rene; Pilz, Wolfgang

    2013-01-01

    Si nanodots of high density and hexagonal short-range order are observed upon normal-incidence bombardment of hot, crystalline Si with Bi 3 + ions having a kinetic energy of a few tens of keV. The heights of nanodots are comparable to their widths of ∝20 nm. The implanted Bi accumulates in tiny Bi nanocrystals in a thin Si top layer which is amorphous due to implantation damage. Light and heavy ions up to Xe cause smoothing of surfaces, but Bi 3 + ions considered here have a much higher mass. Atomistic simulations prove that each Bi 3 + impact deposits an extremely high energy density resulting in a several nanometer large melt pool, which resolidifies within a few hundreds of picoseconds. Experiments confirm that dot patterns form only if the deposited energy density exceeds the threshold for melting. Comparing monatomic and polyatomic Bi ion irradiation, Bi-Si phase separation and preferential ion erosion are ruled out as driving forces of pattern formation. A model based on capillary forces in the melt pool explains the pattern formation consistently. High-density Si nanodots are formed by polyatomic Bi ion irradiation of hot Si surfaces. Each impact causes local transient melt pools smaller than the dots. Hexagonally ordered patterns evolve by self-organization driven by repeated ion-induced melting of tiny volumes. Homogeneously distributed Bi nanocrystals are found in the a-Si film. These nanocrystals are related to particularities of the Si-Bi phase diagram. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Photoluminescence and photoluminescence excitation studies in 80 MeV Ni ion irradiated MOCVD grown GaN

    Energy Technology Data Exchange (ETDEWEB)

    Devaraju, G. [School of Physics, University of Hyderabad, Central University P.O., Hyderabad 500 046 (India); Pathak, A.P., E-mail: appsp@uohyd.ernet.in [School of Physics, University of Hyderabad, Central University P.O., Hyderabad 500 046 (India); Srinivasa Rao, N.; Saikiran, V. [School of Physics, University of Hyderabad, Central University P.O., Hyderabad 500 046 (India); Enrichi, Francesco [Coordinamento Interuniversitario Veneto per le Nanotecnologie (CIVEN), via delle Industrie 5, Marghera, I-30175Venice (Italy); Trave, Enrico [Dipartimento di Chimica Fisica, Universita Ca' Foscari Venezia, Dorsoduro 2137, I-30123 Venice (Italy)

    2011-09-01

    Highlights: {yields} MOCVD grown GaN samples are irradiated with 80 MeV Ni ions at room temperature. {yields} PL and PLE studies have been carried out for band to band, BL and YL emissions. {yields} Ni ions irradiated GaN shows BL band at 450 nm besides YL band. {yields} Radiation annealed Ga vacancies have quenching effect on YL intensity. {yields} We speculated that BL and YL are associated with N and Ga vacancies, respectively. - Abstract: We report damage creation and annihilation under energetic ion bombardment at a fixed fluence. MOCVD grown GaN thin films were irradiated with 80 MeV Ni ions at a fluence of 1 x 10{sup 13} ions/cm{sup 2}. Irradiated GaN thin films were subjected to rapid thermal annealing for 60 s in nitrogen atmosphere to anneal out the defects. The effects of defects on luminescence were explored with photoluminescence measurements. Room temperature photoluminescence spectra from pristine sample revealed presence of band to band transition besides unwanted yellow luminescence. Irradiated GaN does not show any band to band transition but there is a strong peak at 450 nm which is attributed to ion induced defect blue luminescence. However, irradiated and subsequently annealed samples show improved band to band transitions and a significant decrease in yellow luminescence intensity due to annihilation of defects which were created during irradiation. Irradiation induced effects on yellow and blue emissions are discussed.

  9. Microbeam line of MeV heavy ions for materials modification and in-situ analysis

    International Nuclear Information System (INIS)

    Horino, Yuji; Chayahara, Akiyoshi; Kiuchi, Masato; Fujii, Kanenaga; Satoh, Mamoru; Takai, Mikio.

    1990-01-01

    A microbeam line for MeV heavy ions of almost any element has been developed for microion-beam processing such as maskless MeV ion implantation and its in-situ analysis. Beam spot sizes of 4.0 μm x 4.0 μm for 3 MeV C 2+ and 9.6 μm x 4.8 μm for 1.8 MeV Au 2+ beams were obtained. Maskless MeV gold ion implantation to a silicon substrate and in-situ microanalysis before and after ion implantation were demonstrated. (author)

  10. Treatment of PVC using an alternative low energy ion bombardment procedure

    Science.gov (United States)

    Rangel, Elidiane C.; dos Santos, Nazir M.; Bortoleto, José Roberto R.; Durrant, Steven F.; Schreiner, Wido H.; Honda, Roberto Y.; Rangel, Rita de Cássia C.; Cruz, Nilson C.

    2011-12-01

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  11. Treatment of PVC using an alternative low energy ion bombardment procedure

    International Nuclear Information System (INIS)

    Rangel, Elidiane C.; Santos, Nazir M. dos; Bortoleto, José Roberto R.; Durrant, Steven F.; Schreiner, Wido H.; Honda, Roberto Y.; Cássia C Rangel, Rita de; Cruz, Nilson C.

    2011-01-01

    In many applications, polymers have progressively substituted traditional materials such as ceramics, glasses, and metals. Nevertheless, the use of polymeric materials is still limited by their surface properties. Frequently, selective modifications are necessary to suit the surface to a given application. Amongst the most common treatments, plasma immersion ion implantation (PIII) has attracted the attention of many researchers owing to its versatility and practicality. This method, however, requires a power supply to provide high voltage (tens of kV) negative pulses, with a controlled duty cycle, width and frequency. Owing to this, the implementation of PIII on the industrial scale can become economically inviable. In this work, an alternative plasma treatment that enables low energy ion bombardment without the need of a high voltage pulse generator is presented. To evaluate the efficiency of the treatment of polymers, polyvinylchloride, PVC, specimens were exposed to 5 Pa argon plasmas for 3600 s, at excitation powers, P, of between 10 and 125 W. Through contact angle and atomic force microscopy data, the influence of P on the wettability, surface free energy and roughness of the samples was studied. Surface chemical composition was measured by X-ray photoelectron spectroscopy, XPS. To evaluate the effect of aging under atmospheric conditions, contact angle and XPS measurements were performed one and 1334 days after the treatment. The plasma potential and ion density around the driven electrode were determined from Langmuir probe measurements while the self-bias potential was derived with the aid of an oscilloscope. From these data it was possible to estimate the mean energy of ions bombarding the PVC surface. Chlorine, carbon and oxygen contamination were detected on the surface of the as-received PVC. Upon exposure to the plasma, the proportion of chlorine was observed to decrease while that of oxygen increased. Consequently, the wettability and surface energy

  12. Spatial distribution of bremsstrahlung in water and water-iron by 22-MeV electron bombardment measured with activation detectors

    International Nuclear Information System (INIS)

    Nakamura, Takashi; Nishimoto, Takanao; Hirayama, Hideo.

    1977-01-01

    The spatial distributions of bremsstrahlung in water (1 m thick) and water (60 cm thick)-iron (6.3 cm thick) bombarded by 22-MeV electrons were measured by using a new activation method which we developed. These informations are useful for studying shielding, residual activity and radiation damage of accelerator and target materials. From the measured activities, the bremsstrahlung spectra in water were evaluated with the LYRA and the SAND-II unfolding codes. The evaluated spectra were in good agreement with the analytical calculation by the DIBRE code, except for the higher energy ends. The longitudinal and the lateral distributions of bremsstrahlung flux in water were obtained by integrating the evaluated spectra above 8 MeV. The agreement of the experimental and the calculated flux distributions was very good except for a large angle to beam direction. The total photon number crossing a plane normal to the beam axis attenuates exponentially along the axial depth. The iso-flux contour of bremsstrahlung flux was given by interpolating the flux distribution curves. Only the saturated activities of gold detectors were obtained for water-iron in good experimental accuracy. The spatial distribution of gold saturated activities in water-iron clearly shows the attenuating effect due to strong absorption in iron. (auth.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-15

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  15. Data on ionization, excitation, dissociation and dissociative ionization of targets by helium ion bombardments, (1)

    International Nuclear Information System (INIS)

    Oda, Nobuo; Urakawa, Junji

    1984-03-01

    This report presents a compilation of the experimental data on cross sections for the ionization, excitation, dissociation and dissociative ionization processes of targets in helium ion impacts on atoms and molecules under a single collision condition. These measurements were carried out in the energy range from several keV to 3.5 MeV. A systematic survey has been made on the literatures from 1975 to the end of 1982. A list of references is also given, including relevant papers published before 1975. (author)

  16. Diamond-like carbon prepared by pulsed laser deposition with ion bombardment: physical properties

    Science.gov (United States)

    Písařík, P.; Mikšovský, J.; Remsa, J.; Zemek, J.; Tolde, Z.; Jelínek, M.

    2018-01-01

    Diamond-like carbon (DLC) and titanium-doped DLC thin films were prepared by unique hybrid system consisting of pulsed laser deposition, ion source (bombardment) and magnetron sputtering. The influence of deposition parameters (ion energies, deposition pressures and magnetron power) on composition and physical properties was studied. Composition and sp 3/ sp 2 ratio were determined by XPS. sp 3/ sp 2 ratio was in the range from 1.4 to 2.2 for undoped DLC and from 3.4 to 4.8 for Ti-DLC. AFM showed that the layers were smooth, but with small amounts of random droplets. The measurements of the contact angle and determination of surface free energy were made for water, diiodomethane and ethylene glycol. Hardness and reduced Young's modulus varied from 20 to 31 GPa and from 182 to 276 GPa, respectively. Film adhesion was determined by scratch test; L C3 reached 23 N for DLC and 27 N for TiDLC. Optimization of sp 3/ sp 2 ratio, hardness and adhesion to biomedical alloys will advance the DLC coatings usability in the field of implantology.

  17. Effect of Ni +-ION bombardment on nickel and binary nickel alloys

    Science.gov (United States)

    Roarty, K. B.; Sprague, J. A.; Johnson, R. A.; Smidt, F. A.

    1981-03-01

    Pure nickel and four binary nickel alloys have been subjected to high energy Ni ion bombardment at 675, 625 and 525°C. After irradiation, each specimen was studied by transmission electron microscopy. The pure nickel control was found to swell appreciably (1 to 5%) and the Ni-Al and the Ni-Ti samples were found to swell at all temperatures, but to a lesser degree (0.01 to 0.35%). The Ni-Mo contained a significant density of voids only at 525° C, while swelling was suppressed at all temperatures in the Ni-Si alloy. The dislocation structure progressed from loops to tangles as temperature increased in all materials except the Ni-Ti, in which there was an absence of loops at all temperatures. Dislocation densities decreased as temperature increased in all samples. These results do not correlate well with the relative behavior of the same alloys observed after neutron irradiation at 455°C. The differences between these two sets of data appear to be caused by different mechanisms controlling void nucleation in ion and neutron irradiation of these alloys.

  18. Ion-beam bombardment induced texture in nickel substrates for coated high-Tc superconductors

    International Nuclear Information System (INIS)

    Wang, S S; Wu, K; Zhou, Y; Godfrey, A; Meng, J; Liu, M L; Liu, Q; Liu, W; Han, Z

    2003-01-01

    Biaxially textured metal substrates are often used for making YBa 2 Cu 3 O 7-x coated conductors with high critical current density. Generally, specific rolling and high-temperature annealing procedures are required to obtain the biaxial texture for metal substrates. Here, we report on a new method for developing strongly biaxially textured grain structure in rolled nickel tape by argon ion-beam bombardment. X-ray diffraction (XRD) θ-2θ scans have shown that a (200) diffraction peak intensity of the Ni foil processed by ion-beam structure modification (ISM) is two orders of magnitude greater than that of cold-rolled foil, while the (111) and (220) intensities are very weak. In the ISM processed Ni foils, from the rocking curve, the full width at half maximum (FWHM) value of the (200) peak has been found to be less than 5.9 deg., whilst the in-plane FWHM obtained from a pole figure analysis is just 8 deg. We discuss the possible mechanisms leading to the texture changes during ISM. (rapid communication)

  19. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    Science.gov (United States)

    Cernusca, S.; Winter, HP.; Aumayr, F.; Díez Muiño, R.; Juaristi, J. I.

    2003-04-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to "projectile molecular effects" (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  20. MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films

    Science.gov (United States)

    Budak, S.; Heidary, K.; Johnson, R. B.; Colon, T.; Muntele, C.; Ila, D.

    2014-08-01

    The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S2σT/K, where, S and σ denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or σ or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

  1. MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films

    Energy Technology Data Exchange (ETDEWEB)

    Budak, S., E-mail: satilmis.budak@aamu.edu [Department of Electrical Engineering and Computer Science, Alabama A and M University, Huntsville, AL (United States); Heidary, K. [Department of Electrical Engineering and Computer Science, Alabama A and M University, Huntsville, AL (United States); Johnson, R.B.; Colon, T. [Department of Physics, Alabama A and M University, Huntsville, AL (United States); Muntele, C. [Cygnus Scientific Services, Huntsville, AL (United States); Ila, D. [Department of Physics, Fayetteville St. University, Fayetteville, NC (United States)

    2014-08-15

    The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S{sup 2}σT/K, where, S and σ denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or σ or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

  2. Calculation of energy and angular distributions of the bremsstrahlung of 10 MeV electrons bombarding a thick tungsten target

    International Nuclear Information System (INIS)

    Tsovbun, V.I.

    1977-01-01

    Computer calculations have been performed to extend the data available on energy and angular distribution of the 10 MeV electron bremsrahlung into a higher angle region. The ETRAN-16D program developed by R.G.Berger for calculation of electron-photon cascades passing through matter using computers IBM-360 and UNIVAC-1108 was modified to operate with the CDC-6500 computer. A brief summary of the program is provided. An angular distribution of the bremsstrahlung dose absorbed in the air has been also calculated. The results extended into the 90-180 deg region can be used to calculate the biological shield of electron accelerators

  3. Low-energy ion bombardment to tailor the interfacial and mechanical properties of polycrystalline 3C-silicon carbide

    International Nuclear Information System (INIS)

    Liu Fang; Li, Carolina H.; Pisano, Albert P.; Carraro, Carlo; Maboudian, Roya

    2010-01-01

    Low-energy Ar + ion bombardment of polycrystalline 3C-silicon carbide (poly-SiC) films is found to be a promising surface modification method to tailor the mechanical and interfacial properties of poly-SiC. The film average stress decreases as the ion energy and the bombardment time increase. Furthermore, this treatment is found to change the strain gradient of the films from positive to negative values. The observed changes in stress and strain gradient are explained by ion peening and thermal spikes models. In addition, the poly-SiC films show a significant enhancement in corrosion resistance by this treatment, which is attributed to a reduction in surface energy and to an increase in the compressive stress in the near-surface region.

  4. Changes in phase composition and stress state of surface layers of VK20 hard alloy after ion bombardment

    International Nuclear Information System (INIS)

    Platonov, G.L.; Leonov, E.Yu.; Anikin, V.N.; Anikeev, A.I.

    1988-01-01

    Titanium ion bombardment of the surface of the hard VK20 alloy is studied for its effect on variations in the phase and chemical composition of its surface layers. It is stated that ion treatment results in the appearance of the η-phase of Co 6 W 6 C composition in the surface layer of the VK20 alloy, in the increase of distortions and decrease of coherent scattering blocks of the hard alloy carbide phase. Such a bombardment is found to provoke a transition of the plane-stressed state of the hard alloy surface into the volume-stressed state. It is established that ion treatment does not cause an allotropic transition of the cobalt phase α-modification, formed during grinding of the hard alloy, into the β-modification

  5. Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Schulze, P.D.

    1983-01-01

    The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using x-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O 2 , NO, N 2 O, and CO at 300 K and the adsorption of O 2 and D 2 O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O 2 adsorbs dissociatively on ilmenite while D 2 O adsorbs molecularly below 170K. Above 300 K NO, N 2 O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D 2 O was found to be inhibited by predosing the ilmenite with O 2

  6. Ion bombardment and adsorption studies on ilmenite (FeTiO3) by X-ray photoelectron spectroscopy

    Science.gov (United States)

    Schulze, P. D.

    1983-01-01

    The effects of 5 KeV argon and oxygen ion bombardment on FeTiO3 (ilmenite) at low temperatures have been studied using X-ray photoelectron spectroscopy (XPS). Also, using this same technique, the adsorption of O2, NO, N2O, and CO at 300 K and the adsorption of O2 and D2O at 150K have been studied. Argon and oxygen ion bombardment of ilmenite have confirmed earlier studies on metal oxides that argon ions generally reduce the anion species while oxygen ions generally oxidize the anion species. The two iron states involved were Fe sup +2 and Fe sup O. The reduction of Ti sup +4 was not verified although a significant shift in the Ti(2p1,3) binding energies toward the metallic state was observed after oxygen ion bombardment at low temperatures. At temperatures above 150K, O2 adsorbs dissociatively on ilmenite while D2O adsorbs molecularly below 170K. Above 300 K No, N2O, and CO do not appear to adsorb dissociatively. Low temperature adsorption of D2O was found to be inhibited by predosing the ilmenite with O2.

  7. Mechanism of conductivity type conversion in p-Hg1-xCdxTe crystals under low energy ion bombardment

    International Nuclear Information System (INIS)

    Bogoboyashchij, V.V.; Izhnin, I.I.

    2000-01-01

    Conditions giving rise to accelerated diffusion of Hg under bombardment of p-Hg 1-x Cd x Te by low-energy particles are analyzed and probable mechanisms of the phenomenon are suggested, permitting qualitative and quantitative agreement with experimental data. Analysis indicates that basic regularities of p-n-conversion during Hg 0.8 Cd 0.2 Te crystal bombardment by neutralized ions can be easily explained in the framework of traditional notions of mercury chemical diffusion in this material. The regularities stem from specific features of defect formation in Hg 0.8 Cd 0.2 Te, on the one hand, and from a high concentration of intrinsic electrons and holes, screening effectively the defective layer electric field, on the other hand. The high rate of conversion during ion bombardment compared with the rate of conversion during annealing in mercury vapors can be explained by the fact that a great number of nonequilibrium interstitial atoms of mercury, by far exceeding the value during thermal annealing, is crated near the surface of the crystal bombarded [ru

  8. The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

    International Nuclear Information System (INIS)

    Li, Li; Liu, Honglin; Zou, Lin; Ding, Wanyu; Ju, Dongying; Chai, Weiping

    2013-01-01

    The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

  9. The effect of oxygen ion beam bombardment on the properties of tin indium oxide/polyethylene terephthalate complex

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li; Liu, Honglin; Zou, Lin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Ding, Wanyu, E-mail: dwysd_2000@163.com [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116028 (China); Ju, Dongying [Department of Material Science and Engineering, Saitama Institute of Technology, Fukaya 369-0293 (Japan); Chai, Weiping [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)

    2013-10-31

    The tin indium oxide (ITO) films were deposited onto the polyethylene terephthalate (PET) surface that has been bombarded by an O ion beam. The variation of the O bombardment time resulted in the production of ITO/PET complex with different properties. Characterization by four-point probe measurement after the bending fatigue test showed that the adhesion property of the ITO/PET complex could be improved by the increase of O bombardment time while little change of electrical resistivity was observed. Scanning electron microscopy results showed that after the bending fatigue test, the nano scale seams and micro scale trenches appeared at the surface of the ITO/PET complex. The former was only the cracks of ITO film, which has little influence on the continuity and electrical resistivity of ITO film. On the contrary, the micro scale trenches were caused by the peeling off of ITO chips at the cracks, which mainly influenced the continuity and electrical resistivity of ITO film. With the increase of O bombardment time, the number and length of the micro scale trenches decreased. X-ray photoelectron spectrometry characterization showed that with the increase of O bombardment time, parts of the methylene C bonds were transformed into C=O bonds, which could be broken to form C-O-In(Sn) bonds at the initial stage of ITO film growth. By these C-O-In(Sn) crosslink bonds, the ITO film could adhere well onto the PET and the ITO/PET complex display better anti-bending fatigue property. Finally, in the context of the application of the ITO/PET complex as a flexible electrode substrate, the present work reveals a simple way to crosslink them, as well as the physicochemical mechanism happening at the interface of complex. - Highlights: • Polyethylene terephthalate (PET) surface was bombarded by N ions. • Tin indium oxide (ITO) film was deposited on bombarded PET surface. • By bombardment, methylene C bond on PET surface was broken and replaced by C=O bond. • C=O bond was

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

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

  12. Identification and imaging of modern paints using Secondary Ion Mass Spectrometry with MeV ions

    DEFF Research Database (Denmark)

    Bogdanović Radović, Iva; Siketić, Zdravko; Jembrih-Simbürger, Dubravka

    2017-01-01

    Secondary Ion Mass Spectrometry using MeV ion excitation was applied to analyse modern paint materials containing synthetic organic pigments and binders. It was demonstrated that synthetic organic pigments and binder components with molecular masses in the m/z range from 1 to 1200 could be identi......Secondary Ion Mass Spectrometry using MeV ion excitation was applied to analyse modern paint materials containing synthetic organic pigments and binders. It was demonstrated that synthetic organic pigments and binder components with molecular masses in the m/z range from 1 to 1200 could...... be identified in different paint samples with a high efficiency and in a single measurement. Different ways of mounting of mostly insulating paint samples were tested prior to the analysis in order to achieve the highest possible yield of pigment main molecular ions. As Time-of-Flight mass spectrometer for Me......V Secondary Ion Mass Spectrometry is attached to the heavy ion microprobe, molecular imaging on cross-sections of small paint fragments was performed using focused ions. Due to the fact that molecules are extracted from the uppermost layer of the sample and to avoid surface contamination, the paint samples...

  13. The reaction 12C + 12C at bombarding energies from 5 to 10 MeV per nucleon

    International Nuclear Information System (INIS)

    Morsad, A.

    1986-01-01

    The reaction 12 C + 12 C has been studied for energies ranging from E LAB = 60 to 120 MeV. The excitation functions and angular distributions were obtained for the elastic (0 + , 0 + ) and inelastic (2 + , 0 + ), (2 + , 2 + ) channels as well as for the transfer channels of one and two nucleons. For the transfer reactions, the feeding of the final bound states was very selective. Narrow correlated structures were found in the transfer and especially in the elastic and inelastic channels. In this energy range, there appears to be a transition from surface transparency to interference phenomena. The optical model in its simplest form is unable to describe the elastic scattering at large angles. This has been interpreted as a consequence of the coupling between the elastic and inelastic channels which is particularly strong of these energies. 80 refs [fr

  14. DC and RF ion accelerators for MeV energies

    International Nuclear Information System (INIS)

    Urbanus, W.H.

    1990-01-01

    This thesis deals with the transport and acceleration of intense ion beams in single-ended Van de Graaff accelerators and the multiple beam rf accelerator MEQALAC (Multiple Electrostatic Quadrupole Array Linear Accelerator). Ch. 2 discusses several beam-envelope calculation techniques and describes the ion-optical components of a 1 MV, high-current, heavy-ion implantation facility and a 2 MV facility for analyzing purposes. The X-ray level of these accelerators is kept low, such that no shielding is needed, by keeping the energy of the secondary electrons sufficiently low, which is accomplished by a suppression system of small permanent magnets built in the acceleration tubes (ch. 3). Ch.'s 4,5 and 6 cover various aspects of stage II of the MEQALAC project. This stage deals with the parallel acceleration of four high-current N + beams from 40 keV to 1 MeV. Acceleration takes place in 32 rf gaps which are part of a modified interdigital H-resonator. In between the accelerating gaps, small electrostatic quadrupoles are mounted, which oppose the space charge forces of the intense ion beams. The lenses are arranged in a periodic focusing structure. A bucket-type plasma ion source is used, which produces both N + and N 2 + ions. In between the ion source and the MEQALAC section, a Low Energy Beam Transport (LEBT) section is mounted which provides for the drift space for a buncher. The latter device transforms the extracted dc beams into bunched beams which are accepted by the MEQALAC section. In ch. 4 the transport of ion beams that contain both N + and N 2 + ions, so-called mixed beams, through the LEBT section is discussed and equations for the current limit of a mixed beam are derived. Bunching of mixed N + , N 2 + beams is discussed in ch. 5. Multichannel acceleration of N + ions with the MEQALAC is discussed in ch. 6. (author). 122 refs.; 67 figs.; 1 tab

  15. Ejection of fast recoil atoms from solids under ion bombardment (medium-energy ion scattering by solid surfaces: Pt. 3)

    International Nuclear Information System (INIS)

    Dodonoy, A.I.; Mashkova, E.S.; Molchanov, V.A.

    1989-01-01

    This paper is the third part of our review surface scattering. Part I, which was devoted to the scattering of ions by the surfaces of disordered solids, was published in 1972; Part II, concerning scattering by crystal surfaces, was published in 1974. Since the publication of these reviews the material contained in them has become obsolete in many respects. A more recent account of the status of the problem has been given in a number of studies, including the book by E.S. Mashkova and V.A. Molchanov, Medium-Energy Ion Scattering by Solid Surfaces (Atomizdat, Moscow, 1980), than extended version of which was published by North-Holland in 1985. We note, however, that at the time these reviews were written the study of fast recoil atoms had not been carried out systematically; the problem was studied only as a by-product of surface scattering and sputtering. For this reason, in the above-mentioned works and in other reviews the data relating to recoil atoms were considered only occasionally. In recent years there have appeared a number of works - theoretical, experimental and computer -specially devoted to the study of the ejection of recoil atoms under ion bombardment. A number of interesting effects, which are due to the crystal structure of the target, have been discovered. It therefore, appeared desirable to us to systematize the available material and to present it as Part III of our continuing review. (author)

  16. Production of Oxidants by Ion Bombardment of Icy Moons in the Outer Solar System

    Directory of Open Access Journals (Sweden)

    Philippe Boduch

    2011-01-01

    Full Text Available Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc. of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

  17. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M L; Roberts, A; Nugent, K; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  18. Focussed MeV ion beam implanted waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Von Bibra, M.L.; Roberts, A.; Nugent, K.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Single mode buried optical waveguides have been fabricated in fused silica by MeV proton implantation using a focussed hydrogen ion beam. The technique has the potential to direct write waveguide devices and produce multi-layered structures, without the need for intermediate steps such as mask fabrication or layered depositions. A micron resolution Confocal Raman Spectrometer has been used to map the distribution of atomic vacancies that forms the waveguiding region. The results are compared with theoretical calculations. Losses of 3 dB cm{sup -1} have been measured in unannealed samples, which decreases to less than 0.5 dB cm{sup -1} after annealing at 500 degrees Celsius. We describe methods for determining the refractive index distribution of single mode buried waveguides from their output intensity distributions via an inversion of the scalar wave equation. (authors). 5 figs.

  19. Influence of keV-He ion bombardment on the magnetic properties of Co/Pd multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Mueglich, Nicolas; Buhl, Oliver; Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel (Germany); Hellwig, Olav [San Jose Research Center, HGST, A Western Digital Company, CA (United States)

    2013-07-01

    Thin films of ferromagnetic Co separated by Pd films with thicknesses in the first ferromagnetic maximum of interlayer exchange coupling are magnetically dominated by perpendicular-to-plane anisotropy and labyrinth stripe domain patterns in remanence. During the magnetization reversal of such a multilayer system domain nucleation and domain wall movement can be observed for different external magnetic fields H. The influence of keV-He ion bombardment on the microstructure of the system and its resultant decrease of magnetic anisotropy has been investigated by vibrating sample magnetometry, polar magneto-optical Kerr effect and magnetic force microscopy. It is shown that areas of ferromagnetic in-plane anisotropy are created due to the ion bombardement and that the system shows an increasing quotient of superparamagnetism in the deeper layers of the multilayersystem.

  20. Compositional disordering of GaAs/AlGaAs multiple quantum wells using ion bombardment at elevated temperatures

    International Nuclear Information System (INIS)

    Anderson, K.K.; Donnelly, J.P.; Wang, C.A.; Woodhouse, J.D.; Haus, H.A.

    1988-01-01

    A new method has been developed for compositional mixing of heterostructures by ion bombardment at elevated temperatures. Complete mixing of a 1-μm-thick GaAs/AlGaAs 40-period multiple quantum well layer has been achieved by bombardment with 380 keV Ne + ions for 1 h with the sample at 700 0 C. This temperature is much lower than the annealing temperatures used in other vacancy-enhanced disordering techniques, and even lower temperatures and shorter durations should be possible. Compositional disordering is verified by sputter-profile Auger electron spectroscopy and transmission electron microscopy. Complete mixing is also demonstrated by optical transmission spectra of the disordered material, which exhibit the same band edge as a uniform alloy with the average aluminum mole fraction of the multiple quantum well layer

  1. Temperature effect on the formation of a relief of diamond-like carbon coatings and its modification by ion bombardment

    International Nuclear Information System (INIS)

    Rubshtein, A.P.; Trakhtenberg, I.Sh.; Yugov, V.A.; Vladimirov, A.B.; Plotnikov, S.A.; Ponosov, Yu.S

    2006-01-01

    Using the method of pulsed arc sputtering of a graphite target the diamond-like coatings (DLC) ∼1.5 μm thick are deposited on a steel R6M5 substrate. The relief of the coatings obtained under various temperature conditions is investigated. Variations of carbon DLC surfaces are followed after their bombardment with accelerated argon or chemically active oxygen ions. Argon ion bombardment is established to be preferred for producing a smoothed-out DLC relief. It is shown that a DLC relief should be taken into account when measuring microhardness. It is recommended that transformation of interatomic bonds in irradiated subsurface layers be taken into consideration if information index of methods applied constitutes several monolayers [ru

  2. Selective laser-induced photochemical dry etching of semiconductors controlled by ion-bombardment-induced damage

    International Nuclear Information System (INIS)

    Ashby, C.I.H.; Myers, D.R.; Vook, F.L.

    1987-01-01

    When a photochemical dry etching process requires direct participation of photogenerated carriers in the chemical reaction, it is sensitive to the electronic properties of the semiconductor. For such solid-excitation-based dry etching processes, the balance between reaction and carrier recombination rates determines the practical utility of a particular reaction for device fabrication. The distance from the surface at which the photocarriers are generated by light adsorption is determined by the absorption coefficient. In the absence of an external bias potential, only those carriers formed within a diffusion length of the surface space-charge region will have an opportunity to drive the dry etching reaction. When the absorption coefficient is high, most of the photons generate carriers within a diffusion length from the surface space-charge region, and the etching rate is largely determined by the balance between the rate of the carrier-driven reaction and the surface recombination velocity. When the recombination rate of free carriers in the bulk of the semiconductor is high, the effective diffusion length is reduced and fewer of the carriers generated in the subsurface region ever reach the surface. An important effect of ion bombardment is the creation of many lattice defects that increase the rate of recombination of electrons and holes. When a sufficient number of defects, which act as recombination sites, are formed during ion implantation, the recombination of photogenerated carriers at these defects in the subsurface region can greatly reduce the number of carriers which can reach the surface and drive a photochemical etching reaction

  3. Ion bombardment induced damage in silicon carbide studied by ion beam analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, E.; Kotai, E. [Magyar Tudomanyos Akademia, Budapest (HU). Research Inst. for Particle and Nuclear Physics (RIPNP); Khanh, N.Q.; Horvath, Z.E.; Lohner, T.; Battistig, G.; Zolnai, Z.; Gyulai, J. [Research Inst. for Technical Physics and Materials Science, Budapest (Hungary)

    2001-07-01

    Damage created by implantation of Al{sup +} ions into 4H-SiC is characterized using backscattering spectrometry in combination with channeling. The measurability of the damage profile in the carbon sublattice was demonstrated using the 4260 keV {sup 12}C({alpha},{alpha}){sup 12}C resonance. To create disorder, Al{sup +} ions with energy of 200 keV and 350 keV were implanted at room temperature. As an independent method, cross-sectional transmission electron microscopy was used to study the damage structure in irradiated 4H-SiC. (orig.)

  4. Diamond-like carbon layers modified by ion bombardment during growth and researched by Resonant Ultrasound Spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Kocourek, Tomáš; Jelínek, Miroslav; Písařík, Petr; Remsa, Jan; Janovská, Michaela; Landa, Michal; Zemek, Josef; Havránek, Vladimír

    2017-01-01

    Roč. 417, Sep (2017), s. 213-217 ISSN 0169-4332 R&D Projects: GA ČR(CZ) GA15-05864S Institutional support: RVO:68378271 ; RVO:61388998 ; RVO:61389005 Keywords : in-situ ion bombardment * pulsed laser deposition * diamond-like carbon * hybrid technology * flm modification Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.387, year: 2016

  5. Anomalous time-of-flight distributions observed for argon implanted in silicon and resputtered by Ar+-ion bombardment

    International Nuclear Information System (INIS)

    van Veen, G.N.A.; Sanders, F.H.M.; Dieleman, J.; van Veen, A.; Oostra, D.J.; de Vries, A.E.

    1986-01-01

    A Si substrate is bombarded by 3-keV Ar + ions. From time-of-flight spectra of resputtered Ar neutrals at various target temperatures, we conclude that Ar-bubble formation takes place in the amorphized-Si top layer. The bubbles form and open during etching. The average kinetic energy of the Ar atoms is in agreement with the calculated average potential energy of the Ar atoms inside the bubbles

  6. Determination of intensity and energy spectrum of neutrons by bombardment of thallium-203 thick target and its copper substrate with 28.5 MeV protons

    International Nuclear Information System (INIS)

    Hajiloo, N.; Raisali, Gh.; Hamidi, S.; Aslani, Gh.

    2007-01-01

    In this research we have determined neutrons spectrum and the intensity that produced from thallium target bombardment. We have applied SRIM and ALICE computer codes to thallium target and its copper substrate for 145 μA of 28.5 MeV incident proton beam from cyclotron Cyclone30. Because of the energy degradation of protons while passing through the thallium target and its copper substrate, the average energy of protons in different depths has been calculated by using SRIM computer code. Then, by applying ALICE computer code for each sub-layer, the neutron production cross sections and their energy spectrum have been calculated to determine the total neutron intensity and spectrum. Using the calculated neutron intensity of 1.22x10 13 n/s as the source, the equivalent dose rate at the distance 6 meters from the target has been calculated by MCNP computer code and the result has been compared with the measured value. The Pb 201 activity has also been calculated as 13.5 Curies. The measured Pb 201 activity by Curie meter CAPINTEC CRC-712 is 13.1 Ci which is in reasonable agreement with the calculated value, bearing in mind the uncertainties in the proposed models and the measurements

  7. Potential energy effects and diffusion in the relaxed components of the reaction 197Au + 40Ar at 288 and 340 MeV bombarding energies

    International Nuclear Information System (INIS)

    Moretto, L.G.; Galin, J.; Babinet, R.; Fraenkel, Z.; Schmitt, R.; Jared, R.; Thompson, S.G.

    1976-01-01

    The fragments emitted in the reaction between 197 Au and 40 Ar at 288 and 340 MeV bombarding energies have been studied. The fragments have been identified in atomic number up to Z = 32 by means of an E-ΔE telescope. The kinetic energy distributions, the cross sections and the angular distributions have been measured for each Z. The kinetic energy distributions show the typical quasielastic and relaxed components; the Z-distributions show a smooth increase in the cross section with increasing Z, interrupted at relatively forward angles by a fairly sharp peak close to Z = 18. The angular distributions are forward peaked in excess of 1/sin theta for atomic numbers as large as Z approximately 30, as far as twelve atomic number units above the projectile; this is at variance with other reactions like Ag+ 20 Ne, where the angular distributions become 1/sin(theta) four or five atomic number units above the projectile. This is interpreted in terms of an enhanced diffusion towards symmetry, possibly promoted by the potential energy in the intermediate complex corresponding to two fragments in contact. (Auth.)

  8. Doubly versus singly positively charged oxygen ions back-scattered from a silicon surface under dynamic O2+ bombardment

    International Nuclear Information System (INIS)

    Franzreb, Klaus; Williams, Peter; Loerincik, Jan; Sroubek, Zdenek

    2003-01-01

    Mass-resolved (and emission-charge-state-resolved) low-energy ion back-scattering during dynamic O 2 + bombardment of a silicon surface was applied in a Cameca IMS-3f secondary ion mass spectrometry (SIMS) instrument to determine the bombarding energy dependence of the ratio of back-scattered O 2+ versus O + . While the ratio of O 2+ versus O + drops significantly at reduced bombarding energies, O 2+ back-scattered from silicon was still detectable at an impact energy (in the lab frame) as low as about 1.6 keV per oxygen atom. Assuming neutralization prior to impact, O 2+ ion formation in an asymmetric 16 O→ 28 Si collision is expected to take place via 'collisional double ionization' (i.e. by promotion of two outer O 2p electrons) rather than by the production of an inner-shell (O 2s or O 1s) core hole followed by Auger-type de-excitation during or after ejection. A molecular orbital (MO) correlation diagram calculated for a binary 'head-on' O-Si collision supports this interpretation

  9. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    Science.gov (United States)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-02-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the CO, C-C and CC groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME.

  10. FTIR and Vis-FUV real time spectroscopic ellipsometry studies of polymer surface modifications during ion beam bombardment

    International Nuclear Information System (INIS)

    Laskarakis, A.; Gravalidis, C.; Logothetidis, S.

    2004-01-01

    The continuously increasing application of polymeric materials in many scientific and technological fields has motivated an extensive use of polymer surface treatments, which modify the physical and chemical properties of polymer surfaces leading to surface activation and promotion of the surface adhesion. Fourier transform IR spectroscopic ellipsometry (FTIRSE) and phase modulated ellipsometry (PME) in the IR and Vis-FUV spectral regions respectively have been employed for in situ and real time monitoring of the structural changes on the polymer surface obtained by Ar + ion bombardment. The polymers were industrially supplied polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) membranes. The Ar + ion bombardment has found to change the chemical bonding of the films and especially the amount of the C-O, C-C and C-C groups. The detailed study of the FTIRSE spectra reveals important information about the effect of the Ar + ion bombardment on each of the above bonding groups. Also, the modification of the characteristic features, attributed to electronic transitions in specific bonds of PET and PEN macromolecules, has been studied using PME

  11. Ion peening and stress relaxation induced by low-energy atom bombardment of covalent solids

    International Nuclear Information System (INIS)

    Koster, Monika; Urbassek, Herbert M.

    2001-01-01

    Using molecular-dynamics simulation, we study the buildup and relaxation of stress induced by low-energy (≤150 eV) atom bombardment of a target material. The effect is brought out most clearly by using an initially compressed specimen. As target material, we employ Si, based on the Tersoff potential. By varying the bond strength in the potential, we can specifically study its effect on damage production and stress changes. We find that in general, stress is relaxed by the atom bombardment; only for low bombarding energies and strong bonds, atom bombardment increases stress. We rationalize this behavior by considering the role of energized atoms and of recoil-implanted target atoms

  12. Monte Carlo simulation for neutron yield produced by bombarding thick targets with high energy heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Yoon, Moo Hyun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2013-04-15

    One of radiation shielding issues at heavy-ion accelerator facilities is to estimate neutron production by primary heavy ions. A few Monte Carlo transport codes such as FLUKA and PHITS can work with primary heavy ions. Recently IBS/RISP((Rare Isotope Science Project) started to design a high-energy, high-power rare isotope accelerator complex for nuclear physics, medical and material science and applications. There is a lack of experimental and simulated data about the interaction of major beam, {sup 238}U with materials. For the shielding design of the end of first accelerating section section, we calculate a differential neutron yield using the FLUKA code for the interaction of 18.5 MeV/u uranium ion beam with thin carbon stripper of 1.3 μm). The benchmarking studies were also done to prove the yield calculation for 400 MeV/n {sup 131}Xe and other heavy ions. In this study, the benchmarking for Xe-C, Xe-Cu, Xe-Al, Xe-Pb and U-C, other interactions were performed using the FLUKA code. All of results show that the FLUKA can evaluate the heavy ion induced reaction with good uncertainty. For the evaluation of neutron source term, the calculated neutron yields are shown in Fig. 2. The energy of Uranium ion beam is only 18.5 MeV/u, but the energy of produced secondary neutrons was extended over 100 MeV. So the neutron shielding and the damage by those neutrons is expected to be serious. Because of thin stripper, the neutron intensity at forward direction was high. But the the intensity of produced secondary photons was relatively low and mostly the angular property was isotropic. For the detail shielding design of stripper section of RISP rare istope accelerator, the benchmarking study and preliminary evaluation of neutron source term from uranium beam have been carried out using the FLUKA code. This study is also compared with the evaluation results using the PHITS code performed coincidently. Both studies shows that two monte carlo codes can give a good results for

  13. A 1MeV, 1A negative ion accelerator test facility

    International Nuclear Information System (INIS)

    Hanada, M.; Dairaku, M.; Inoue, T.; Miyamoto, K.; Ohara, Y.; Okumura, Y.; Watanabe, K.; Yokoyama, K.

    1995-01-01

    For the Proof-of-Principle test of negative ion acceleration up to 1 MeV, the beam energy required for ITER, a negative ion test facility named MeV Test Facility (MTF) and an ion source/accelerator have been designed and constructed. They are designed to produce a 1 MeV H- beam at a low source pressure of 0.13Pa. The MTF has a power supply system, which constituts of a 1MV, 1A, 60 s Cockcroft-Walton type dc high energy generator and power supplies for negative ion generation and extraction (ion source power supplies). The negative ion source/accelerator is composed of a cesiated volume source and a 5-stage, multi-aperture, electrostatic accelerator. The MTF and the ion source/accelerator have been completed, and the accelertion test up to 1 MeV of the H- ions has started. (orig.)

  14. Influence of ion bombardment on structure and properties of TiZrN thin film

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yu-Wei, E-mail: james722@itrc.narl.org.tw [Instrument Technology Research Center, National Applied Research Laboratories Taiwan (China); Huang, Jia-Hong; Yu, Ge-Ping [Department of Engineering and System Science, National Tsing Hua University, Taiwan (China); Hsiao, Chien-Nan; Chen, Fong-Zhi [Instrument Technology Research Center, National Applied Research Laboratories, Taiwan (China)

    2015-11-01

    Highlights: • (Ti,Zr)N thin films were produced using dual guns with Ti and Zr targets. • Ti{sub 0.5}Zr{sub 0.5}N shows excellent hardness of 37.8 GPa with exhibiting (1 1 1) preferred orientation. • Resistivity is inverse proportional to the packing density. • Hardness is proportional to the packing density. - Abstract: The study is focused on the characterization of TiZrN thin film by controlling the behavior of ion bombardment. Thin films are grown using radio frequency magnetron sputtering process on Si wafer. The negative bias voltage ranging from −20 V to −130 V was applied to the substrate. The ion current density increases rapidly as substrate bias is lower than −60 V, then slightly increases as the critical value about −60 V is exceeded. At the substrate bias of −60 V, the ion current density is close to 0.56 mA/cm{sup 2}. The resistivity measured by four-point probe decreases from conditions −20 V to −60 V and then increases for substrate bias increases from −60 V to −130 V. The resistivity of TiZrN films is contributed from the packing factor. The N/TiZr ratios about 1 were measured by Rutherford backscattering spectrometer, and the packing factors of TiZrN films can also be obtained by the results of RBS. Field Emission scanning electron microscope (FEG-SEM) is used to characterize the thickness and structure of the deposited TiZrN film. X-ray diffraction (XRD) is used to determine the preferred orientation and lattice parameter. The precursor results of XRD show that all the coating samples exhibited (1 1 1) preferred orientation, and the hardness values of TiZrN films were ranging from 20 to 40 GPa. To sum up the precursor studies, the TiZrN films which can improve the properties from TiN and ZrN is a new ceramic material with higher potential. Following the advance process and analysis research, the structure and properties can be correlated and as a reference for industry application.

  15. Radiation effects in zinc oxide: zinc under bombardment with KeV ions

    International Nuclear Information System (INIS)

    Hastings, J.W.L.

    1967-01-01

    The energy loss, light output, depth of deterioration and the deterioration constant have been determined as a function of energy for various atomic projectiles impinging upon samples of a powdered Zn:Zn phosphor at energies below 105 KeV. The energy loss was observed as a reduction in the light output when projectiles traversed thin regions of previously damaged phosphor. The energy losses for heavier projectiles ( 14 N, 40 Ar, 84 Kr), relative to hydrogen, were found to be lower than those predicted for an amorphous stopping medium. The light output for a given projectile was found to be approximately proportional to the amount of energy lost in electronic collisions. When a phosphor is subjected to prolonged bombardment by heavy ions the deterioration depth is fairly well defined and its value was determined by a measurement of the energy loss of a hydrogen beam in traversing the damaged region. The depths are very large, are proportional to the projectile velocity and seem to be determined to a significant degree by electronic stopping. The deterioration constant, C, is a measure of the ability of a projectile to deteriorate a phosphor and its value is proportional to the number of defects introduced in unit distance along the trajectory of the projectile. The constant was determined from measurements of the efficiencies η, and η o , of partly damaged and undamaged phosphor, respectively, using the observed relationship, C (η/η o - 1) n -1 where n is the irradiation dose. The relative magnitudes of the C values for 14 N, 40 Ar were found to be in agreement with measured nuclear energy loss cross sections for these projectiles. (author)

  16. Momentum transfer with light ions at energies from 70 MeV to 1000 MeV

    International Nuclear Information System (INIS)

    Saint Laurent, F.; Conjeaud, M.; Dayras, R.; Harar, S.; Oeschler, H.; Volant, C.

    1982-01-01

    Angular correlations of fission fragments induced by bombarding a 232 Th target with protons, deuterons and alpha particles of energies from 70 MeV to 1000 MeV have been measured. They give information about the forward momentum imparted to the fissioning nuclei. We present the average values of the transferred linear momentum ([p vertical stroke vertical stroke ]) as a function of the incident energy and propose a classification into three regimes of dominating processes leading to fission: (I) low-energy behaviour, for E/A less than 10 MeV/u [p vertical stroke vertical stroke ]/psub(i) approx. equal to 1. (II) Between 10 MeV/u and about 70 MeV/u, [p vertical stroke vertical stroke ]/psub(i) decreases progressively down to 0.5 but remains proportional to the projectile mass. (III) The region between 70 MeV/u and about 1000 MeV/u corresponds to a transition region where the projectiles, whatever their masses, tend to transfer the same momentum. (orig.)

  17. Identification and imaging of modern paints using Secondary Ion Mass Spectrometry with MeV ions

    Science.gov (United States)

    Bogdanović Radović, Iva; Siketić, Zdravko; Jembrih-Simbürger, Dubravka; Marković, Nikola; Anghelone, Marta; Stoytschew, Valentin; Jakšić, Milko

    2017-09-01

    Secondary Ion Mass Spectrometry using MeV ion excitation was applied to analyse modern paint materials containing synthetic organic pigments and binders. It was demonstrated that synthetic organic pigments and binder components with molecular masses in the m/z range from 1 to 1200 could be identified in different paint samples with a high efficiency and in a single measurement. Different ways of mounting of mostly insulating paint samples were tested prior to the analysis in order to achieve the highest possible yield of pigment main molecular ions. As Time-of-Flight mass spectrometer for MeV Secondary Ion Mass Spectrometry is attached to the heavy ion microprobe, molecular imaging on cross-sections of small paint fragments was performed using focused ions. Due to the fact that molecules are extracted from the uppermost layer of the sample and to avoid surface contamination, the paint samples were not embedded in the resin as is usually done when imaging of paint samples using different techniques in the field of cultural heritage.

  18. Si-nanoparticle synthesis using ion implantation and MeV ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Chulapakorn, T.; Wolff, M.; Primetzhofer, D.; Possnert, G. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Sychugov, I.; Suvanam, S.S.; Linnros, J. [Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden); Hallen, A. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Royal Institute of Technology, School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden)

    2015-12-15

    A dielectric matrix with embedded Si-nanoparticles may show strong luminescence depending on nanoparticles size, surface properties, Si-excess concentration and matrix type. Ion implantation of Si ions with energies of a few tens to hundreds of keV in a SiO{sub 2} matrix followed by thermal annealing was identified as a powerful method to form such nanoparticles. The aim of the present work is to optimize the synthesis of Si-nanoparticles produced by ion implantation in SiO{sub 2} by employing MeV ion irradiation as an additional annealing process. The luminescence properties are measured by spectrally resolved photoluminescence including PL lifetime measurement, while X-ray reflectometry, atomic force microscopy and ion beam analysis are used to characterize the nanoparticle formation process. The results show that the samples implanted at 20%-Si excess atomic concentration display the highest luminescence and that irradiation of 36 MeV {sup 127}I ions affects the luminosity in terms of wavelength and intensity. It is also demonstrated that the nanoparticle luminescence lifetime decreases as a function of irradiation fluence. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    International Nuclear Information System (INIS)

    Cernusca, S.; Winter, H.P.; Aumayr, F.; Diez Muino, R.; Juaristi, J.I.

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials

  20. Molecular projectile effects for kinetic electron emission from carbon- and metal-surfaces bombarded by slow hydrogen ions

    CERN Document Server

    Cernusca, S; Aumayr, F; Diez-Muino, R; Juaristi, J I

    2003-01-01

    Total yields for kinetic electron emission (KE) have been determined for impact of hydrogen monomer-, dimer- and trimer-ions (impact energy <10 keV) on atomically clean surfaces of carbon-fiber inforced graphite used as first-wall armour in magnetic fusion devices. The data are compared with KE yields for impact of same projectile ions on atomically clean highly oriented pyrolytic graphite and polycrystalline gold. We discuss KE yields for the different targets if bombarded by equally fast molecular and atomic ions in view to 'projectile molecular effects' (different yields per proton for equally fast atomic and molecular ions), which are expected from calculated electronic projectile energy losses in these target materials.

  1. Development and evolution of biaxial texture of rolled nickel tapes by ion beam bombardment for high Tc coated conductors

    International Nuclear Information System (INIS)

    Wang, S.S.; Wu, K.; Shi, K.; Liu, Q.; Han, Z.

    2004-01-01

    High quality YBa 2 Cu 3 O 7-x films on metallic substrates with high critical current densities well over 10 6 A/cm 2 can be prepared by the rolling assisted biaxially textured substrates (RABiTS) method. Nickel or its alloys have been used as biaxially textured substrates formed through a specific rolling and high temperature annealing procedures. In this paper, we report a newly developed process for developing biaxial texture in rolled Ni tape by argon ion beam bombardment. It is named the ion-beam structure modification (ISM) process. In the ISM processed Ni foils, X-ray diffraction ω scans showed the full width-half maximum (FWHM) value of the (2 0 0) peak was 5.7 deg. . And the electron back scattering diffraction (EBSP) analysis based on scanning electron microscopy showed good {1 0 0} cubic orientation and the mean grain size was determined as about 25 μm. The texture evolution of rolled Ni foils during ISM process is reported also. For ISM process, local temperature elevation and distribution arises from the ion bombardment, coupled with anisotropic incident ion penetration and propagation as a result of channeling effects in the metal lattice, are expected to play the major roles in the development of grain reorientation in the Ni foil. Due to the simplicity and efficiency of the ISM process, the technique shows a great promise for application in the industrial scale production of long-lengths of superconductor tapes

  2. Improvement of the wear resistance of electroplated Au-Ni coatings by Zr ion bombardment of Ni-B sublayer

    International Nuclear Information System (INIS)

    Lyazgin, Alexander; Shugurov, Artur; Sergeev, Viktor; Neufeld, Vasily; Panin, Alexey; Shesterikov, Evgeny

    2015-01-01

    The effect of bombardment of the Ni-B sublayer by Zr ion beams on the surface morphology and tribomechanical properties of Au-Ni coatings was investigated. It was found that the treatment has no significant effect on the surface roughness and grain size of the Au-Ni coatings, while it provides essential reducing of their friction coefficient and improvement of wear resistance. It is shown that increased wear resistance of these coatings was caused by their strain hardening resulted from localization of plastic strain. The optimal Zr fluence were determined that provide the maximum reduction of linear wear of the coatings

  3. Structural, thermal and optical behavior of 84 MeV oxygen and 120 MeV silicon ions irradiated PES

    International Nuclear Information System (INIS)

    Samra, Kawaljeet Singh; Thakur, Sonika; Singh, Lakhwant

    2011-01-01

    In order to study structural, thermal and optical behavior, thin flat samples of polyethersulfone were irradiated with oxygen and silicon ions. The changes in properties were analyzed using different techniques viz: X-ray diffraction, thermo-gravimetric analysis, Fourier transform infrared, UV-visible and photoluminescence spectroscopy. A noticeable increase in the intensity of X-ray diffraction peaks was observed after irradiation with 84 MeV oxygen ions at low and medium fluences, which may be attributed to radiation-induced cross-linking in polymer. Fourier transform infrared and thermo-gravimetric analysis corroborated the results of X-ray diffraction analysis. No noticeable change in the Fourier transform infrared spectra of oxygen ion irradiated polyethersulfone were observed even at the highest fluence of 1 x 10 13 ions cm -2 , but after irradiation with silicon ions, a reduction in intensity of almost all characteristic bands was revealed. An increase in the activation energy of decomposition of polyethersulfone was observed after irradiation with 84 MeV oxygen ions up to medium fluences but degradation was revealed at higher fluences. Similar trends were observed by photoluminescence analysis.

  4. Nano-scale pattern formation on the surface of HgCdTe produced by ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.B.; Gudymenko, A.I.; Kladko, V.P.; Korchevyi, A.A.; Savkina, R.K.; Sizov, F.F.; Udovitska, R.S. [V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kiev (Ukraine)

    2015-08-15

    Presented in this work are the results concerning formation of nano-scale patterns on the surface of a ternary compound Hg{sub 1-x}Cd{sub x}Te (x ∝ 0.223). Modification of this ternary chalcogenide semiconductor compound was performed using the method of oblique-incidence ion bombardment with silver ions, which was followed by low-temperature treatment. The energy and dose of implanted ions were 140 keV and 4.8 x 10{sup 13} cm{sup -2}, respectively. Atomic force microscopy methods were used for the surface topography characterization. The structural properties of MCT-based structure was analyzed using double and triple crystal X-ray diffraction to monitor the disorder and strain of the implanted region as a function of processing conditions. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  6. Modeling of metal nanocluster growth on patterned substrates and surface pattern formation under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Numazawa, Satoshi

    2012-11-01

    are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multi-dimensional Boolean valued functions in three dimensional lattice space. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. The third topic is the formation of ripple structures on ion bombarded semiconductor surfaces treated in the first topic as the prepatterned substrate of the metallic deposition. This intriguing phenomenon has been known since the 1960's and various theoretical approaches have been explored. These previous models are discussed and a new non-linear model is formulated, based on the local atomic flow and associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important and it is shown that in this case, certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results including some analytic solutions of the nonlinear equation of motions are in very good agreement with experimental observation.

  7. Formation of Amino Acid Precursors by Bombardment of Interstellar Ice Analogs with High Energy Heavy Ions

    Science.gov (United States)

    Kobayashi, Kensei; Mita, Hajime; Yoshida, Satoshi; Shibata, Hiromi; Enomoto, Shingo; Matsuda, Tomoyuki; Fukuda, Hitoshi; Kondo, Kotaro; Oguri, Yoshiyuki; Kebukawa, Yoko

    2016-07-01

    A wide variety of organic compounds have been detected in extraterrestrial bodies. It has been recognized that carbonaceous chondrites contain pristine amino acids [1]. There are several scenarios of the formation of such extraterrestrial amino acids or their precursors. Greenberg proposed a scenario that complex organic compounds were formed in interstellar ices in dense clouds, which were brought into solar system small bodies when the solar system was formed [2]. The ice mantles of interstellar dust particles (ISDs) in dense clouds are composed of H2O, CO, CH3OH, CH4, CO2, NH3, etc. In order to verify the scenario, a number of laboratory experiments have been conducted where interstellar ice analogs were irradiated with high-energy particles [3,4] or UV [5,6], and formation of complex organic compounds including amino acid precursors were detected in the products. Though ion-molecular reactions in gaseous phase and surface reactions on the ice mantles have been studied intensively, much less works on cosmic rays-induced reaction have been reported. In order to study possible formation of complex molecules in interstellar ices, frozen mixtures of water, methanol and ammonia with various mixing ratios were irradiated with high-energy heavy ions such as carbon ions (290 MeV/u) and neon ions (400 MeV/u) from HIMAC, NIRS, Japan. For comparison, gaseous mixtures of water, ammonia, carbon monoxide, carbon dioxide, and/or methane were irradiated with protons (2.5 MeV) from a Tandem accelerator, Tokyo Tech, Japan. Amino acids in the products were determined by cation exchange HPLC after acid hydrolysis. Products, both before and after acid hydrolysis, were also characterized by FT-IR and other techniques. Amino acids were detected in the hydrolyzed products after mixture of CH3OH, NH3 and H2O with various mixing ratios were irradiated with heavy ions, including when their mixing ratio was set close to the reported value of the interstellar ices (10:1:37). In the HIMAC

  8. Polymerization of solid C60 under C60 cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 95, - (2009), s. 867-873 ISSN 0947-8396 R&D Projects: GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : fulleren * cluster * bombardment * polymerization Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.595, year: 2009 http://www.springerlink.com/content/0947-8396

  9. Electron and ion currents relevant to accurate current integration in MeV ion backscattering spectrometry

    International Nuclear Information System (INIS)

    Matteson, S.; Nicolet, M.A.

    1979-01-01

    The magnitude and characteristics of the currents which flow in the target and the chamber of an MeV ion backscattering spectrometer are examined. Measured energy distributions and the magnitude of high-energy secondary electron currents are reported. An empirical universal curve is shown to fit the energy distribution of secondary electrons for several combinations of ion energy, targets and ion species. The magnitude of tertiary electron currents which arise at the vacuum vessel walls is determined for various experimental situations and is shown to be non-negligible in many cases. An experimental arrangement is described which permits charge integrations to 1% arruracy without restricting access to the target as a Faraday cage does. (Auth.)

  10. Production of Mg and Al Auger electrons by noble gas ion bombardment of Mg and Al surfaces. [3 KeV, electron promotion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrante, J; Pepper, S V [National Aeronautics and Space Administration, Cleveland, Ohio (USA). Lewis Research Center

    1976-08-01

    In this letter the relative production efficiency of Mg and Al Auger electrons by He, Ne, Ar, Kr and Xe ion bombardment as a function of ion energy (<=3 keV) is reported. Some comments on the interpretation of the results in terms of electron promotion are also given.

  11. Enhancement of sp3 hybridized C in amorphous carbon films by Ar ion bombardment and Si incorporation

    International Nuclear Information System (INIS)

    Jung, Hae-Suk; Park, Hyung-Ho; Mendieta, I.R.; Smith, D.A.

    2003-01-01

    We report an effective method of increasing the sp 3 hybridization fraction in sputtered amorphous carbon (a-C) film by the combination of Ar ion bombardment and Si incorporation. In the deposition of an a-C film, Ar ion bombardment by controlling the applied bias voltage plays a role in creating high stress in film and causes the local bonding configuration to change to a sp 3 hybridized bond. Simultaneously, the incorporated Si in an a-C network breaks the sp 2 hybridized bonded ring and promotes the formation of a sp 3 hybridized bond. This enhancement of the sp 3 hybridized bonding characteristic is maximized for an a-C film with 23 at. % of Si and 100-150 V of applied bias voltage. In this region, the increase of resistivity, optical band gap, and mechanical hardness of a-C is attributed to the reduction of the sp 2 hybridized bonded ring and increased fraction of the sp 3 hybridized bond. However, at a higher bias voltage above 150 V, the enhancement effect is reduced due to the resputtering and thermally activated reconversion of a sp 3 to a sp 2 hybridized bond

  12. Ion-bombardment-induced reduction in vacancies and its enhanced effect on conductivity and reflectivity in hafnium nitride films

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Zhiqing; Wang, Jiafu; Hu, Chaoquan; Zhang, Xiaobo; Dang, Jianchen; Gao, Jing; Zheng, Weitao [Jilin University, School of Materials Science and Engineering, Key Laboratory of Mobile Materials, MOE, and State Key Laboratory of Superhard Materials, Changchun (China); Zhang, Sam [Nanyang Technological University, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Wang, Xiaoyi [Chinese Academy of Sciences, Key Laboratory of Optical System Advanced Manufacturing Technology, Changchun Institute of Optics, Fine Mechanics and Physics, Changchun (China); Chen, Hong [Jilin University, Department of Control Science and Engineering, Changchun (China)

    2016-08-15

    Although the role of ion bombardment on electrical conductivity and optical reflectivity of transition metal nitrides films was reported previously, the results were controversial and the mechanism was not yet well explored. Here, we show that proper ion bombardment, induced by applying the negative bias voltage (V{sub b}), significantly improves the electrical conductivity and optical reflectivity in rocksalt hafnium nitride films regardless of level of stoichiometry (i.e., in both near-stoichiometric HfN{sub 1.04} and over-stoichiometric HfN{sub 1.17} films). The observed improvement arises from the increase in the concentration of free electrons and the relaxation time as a result of reduction in nitrogen and hafnium vacancies in the films. Furthermore, HfN{sub 1.17} films have always much lower electrical conductivity and infrared reflectance than HfN{sub 1.04} films for a given V{sub b}, owing to more hafnium vacancies because of larger composition deviation from HfN exact stoichiometry (N:Hf = 1:1). These new insights are supported by good agreement between experimental results and theoretical calculations. (orig.)

  13. Properties of TiN coatings deposited by the method of condensation with ion bombardment accompanied by high-energy ion beam

    International Nuclear Information System (INIS)

    Obrezkov, O.I.; Vershok, B.A.; Dormashev, A.B.; Margulev, I.Ya.; Molchanova, S.A.; Andreev, E.S.; Dervuk, V.V.

    2002-01-01

    Vacuum-sputtering adapted commercial facility based coating of stainless steel with titanium nitride followed two procedures: ion bombardment condensation (IBC) and IBC under simultaneous effect of ion beam (IB). The deposition rate was equal to 0.1 μm min -1 ; the investigated coatings were characterized by 2.5 μm depth. Comparison analysis of features and characteristics of the specimens, as well as, full-scale tests of a coated cutting tool enabled to make conclusions about advantages of application of IB assisted IBC technology in contrast to the reference IBC technology [ru

  14. Structural changes IN THE Kh20N45M4B nickel alloys and THE Kh16N15M3B steel due to helium ion bombardment

    International Nuclear Information System (INIS)

    Kalin, B.A.; Chernikov, U.N.; Chernov, I.I.; Kozhevnikov, O.A.; Shishkin, G.N.; Yakushin, V.L.

    1986-01-01

    Using transmission electron microscopy, x-ray structural analysis, and the thermal desorption techniques, the authors carried out a detailed study of the structural and phase changes, defect formation, and helium accumulation in the He + -bombarded 16-15 austenitic steels and 20-45 nickel alloys. Microstructure of the bombarded specimens was studied using the methods of transmission electron microscopy of thin foils in the EVM-100, and EM-301G electron microscopes. Results of x-ray studies on the bombarded specimens are presented. The conducted studies show that bombardment of structural materials with light ions can lead to significant structural damages and changes in the chemical and phase composition of the surface layer. The possible mechanisms of the changes in the chemical and phase composition include selective sputtering and radiation-induced accelerated diffusion of elements in the field of internal lateral stresses developing during the He + implantation process

  15. Anisotropic deformation of metallo-dielectric core-shell colloids under MeV ion irradiation

    International Nuclear Information System (INIS)

    Penninkhof, J.J.; Dillen, T. van; Roorda, S.; Graf, C.; Blaaderen, A. van; Vredenberg, A.M.; Polman, A.

    2006-01-01

    We have studied the deformation of metallo-dielectric core-shell colloids under 4 MeV Xe, 6 and 16 MeV Au, 30 MeV Si and 30 MeV Cu ion irradiation. Colloids of silica surrounded by a gold shell, with a typical diameter of 400 nm, show anisotropic plastic deformation under MeV ion irradiation, with the metal flowing conform the anisotropically deforming silica core. The 20 nm thick metal shell imposes a mechanical constraint on the deforming silica core, reducing the net deformation strain rate compared to that of pure silica. In colloids consisting of a Au core and a silica shell, the silica expands perpendicular to the ion beam, while the metal core shows a large elongation along the ion beam direction, provided the silica shell is thick enough (>40 nm). A minimum electronic energy loss of 3.3 keV/nm is required for shape transformation of the metal core. Silver cores embedded in a silica shell show no elongation, but rather disintegrate. Also in planar SiO 2 films, Au and Ag colloids show entirely different behavior under MeV irradiation. We conclude that the deformation model of core-shell colloids must include ion-induced particle disintegration in combination with thermodynamical effects, possibly in combination with mechanical effects driven by stresses around the ion tracks

  16. Anisotropic deformation of metallo-dielectric core shell colloids under MeV ion irradiation

    Science.gov (United States)

    Penninkhof, J. J.; van Dillen, T.; Roorda, S.; Graf, C.; van Blaaderen, A.; Vredenberg, A. M.; Polman, A.

    2006-01-01

    We have studied the deformation of metallo-dielectric core-shell colloids under 4 MeV Xe, 6 and 16 MeV Au, 30 MeV Si and 30 MeV Cu ion irradiation. Colloids of silica surrounded by a gold shell, with a typical diameter of 400 nm, show anisotropic plastic deformation under MeV ion irradiation, with the metal flowing conform the anisotropically deforming silica core. The 20 nm thick metal shell imposes a mechanical constraint on the deforming silica core, reducing the net deformation strain rate compared to that of pure silica. In colloids consisting of a Au core and a silica shell, the silica expands perpendicular to the ion beam, while the metal core shows a large elongation along the ion beam direction, provided the silica shell is thick enough (>40 nm). A minimum electronic energy loss of 3.3 keV/nm is required for shape transformation of the metal core. Silver cores embedded in a silica shell show no elongation, but rather disintegrate. Also in planar SiO2 films, Au and Ag colloids show entirely different behavior under MeV irradiation. We conclude that the deformation model of core-shell colloids must include ion-induced particle disintegration in combination with thermodynamical effects, possibly in combination with mechanical effects driven by stresses around the ion tracks.

  17. Influence of both ion bombardment and chemical treatment processes on the electrical conductivity of PVC/poly aniline composites

    International Nuclear Information System (INIS)

    Gad, E.A.M.; Ashour, A.H.; Abdel-Hamid, H.M.; Sayed, W.M.

    1999-01-01

    In this article the changes in the electrical conductivity of PVC/poly aniline composites, as temperature consecutively increases, have been measured. The measurement were taken with correspondence to a control series of the composites under two processes:A. Composite samples bombarded with Ar + ions with fluence 2.44 x 10 13 beam ions /cm 2 ., sec 4 of 4 ke V beam energy where argon atoms can induce defects in the surface layer take place. Composite samples treated chemically with concentrated H 2 SO 4 as dopant which reacts with nitrogen atom in aniline. The measurements were also, done with the composites as the ratio of poly(aniline) stepped upward

  18. Uranium targets sandwiched between carbon layers for use on target wheels and on a Wobbler in heavy-ion bombardments

    International Nuclear Information System (INIS)

    Folger, H.; Hartmann, W.; Klemm, J.; Thalheimer, W.

    1989-01-01

    Uranium layers of ≅ 0.4 mg/cm 2 are evaporated by means of a 6 kW electron-beam gun onto 0.04 mg/cm 2 thick carbon films in a high-vacuum process; a protecting layer of ≅ 0.01 mg/cm 2 of carbon is added in the same vacuum cycle. The evaporation- and deposition yields are discussed and measurements of target characteristics are described. C/U/C sandwich targets in the shape of a sector of an annulus are prepared for use on rotating target wheels of 155 mm radius to be bombarded with a pulsed beam of heavy ions. One type of circular targets of 20 mm in diameter is mounted to a target wobbler. Both, wheel and wobbler, distribute the intensity of the heavy-ion beam to a larger area to reduce radiation damages. Examples of target applications will be mentioned. (orig.)

  19. X-ray diffraction study of stress relaxation in cubic boron nitride films grown with simultaneous medium-energy ion bombardment

    International Nuclear Information System (INIS)

    Abendroth, B.; Gago, R.; Eichhorn, F.; Moeller, W.

    2004-01-01

    Relaxation of the intrinsic stress of cubic boron nitride (cBN) thin films has been studied by x-ray diffraction (XRD) using synchrotron light. The stress relaxation has been attained by simultaneous medium-energy ion bombardment (2-10 keV) during magnetron sputter deposition, and was confirmed macroscopically by substrate curvature measurements. In order to investigate the stress-release mechanisms, XRD measurements were performed in in-plane and out-of-plane geometry. The analysis shows a pronounced biaxial state of compressive stress in the cBN films grown without medium-energy ion bombardment. This stress is partially released during the medium-energy ion bombardment. It is suggested that the main path for stress relaxation is the elimination of strain within the cBN grains due to annealing of interstitials

  20. Influence of helium-ion bombardment on the surface properties of pure and ammonia-adsorbed water thin films

    International Nuclear Information System (INIS)

    Kondo, M.; Shibata, T.; Kawanowa, H.; Gotoh, Y.; Souda, R.

    2005-01-01

    The influence of the ion bombardment on the surface properties of water-ice films has been investigated. The films are irradiated with 1.5 keV He + ions and analyzed sequentially on the basis of time-of-flight secondary-ion mass spectrometry (TOF-SIMS). In order to minimize any temperature-induced effects, the measurements were made at 15 K. The damage of the films, as estimated from the H/D exchange between NH 3 and the D 2 O ice and the intermixing of NH 3 with the H 2 18 O ice, is recognized at the fluence above 2 x 10 14 ions/cm 2 . The sputtering yield of the D 2 O ice is determined as 0.9 ± 0.2 molecules per incoming He + ion. The temperature-programmed TOF-SIMS analysis of the water-ice films has been completed within the fluence of 5.8 x 10 12 ions/cm 2 , so that no appreciable damage of the film should be induced during the measurement

  1. Search for diffusion of counter-passing MeV ions in the TFTR tokamak

    International Nuclear Information System (INIS)

    Zweben, S.J.; Boivin, R.; Chang, C.S.; Hammett, G.; Mynick, H.E.

    1991-07-01

    Confinement studies of MeV ions will play an important role in the research leading to burning plasmas in tokamaks, since any significant radial transport of MeV alpha particles will affect the heating rate or heating profiles of these plasmas. Because the energy, gyroradius, and collisionality of these MeV ions is very different from that of the background plasma, their transport rates cannot be assumed equal to those of the bulk plasma ions. Note that the desired confinement time for 3.5 MeV alphas is set by their thermalization time, which can be up to τ th,α ∼1 sec for the steady-state phase of ITER, requiring D 2 /sec. This is equivalent to over ∼100,000 alpha particle transits of the torus. 28 refs., 24 figs., 2 tabs

  2. XRD study of yttria stabilized zirconia irradiated with 7.3 MeV Fe, 10 MeV I, 16 MeV Au, 200 MeV Xe and 2.2 GeV Au ions

    Energy Technology Data Exchange (ETDEWEB)

    Nakano, K.; Yoshizaki, H. [Department of Materials Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Saitoh, Y. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Ishikawa, N. [Tokai Research and Development Center, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Iwase, A., E-mail: iwase@mtr.osakafu-u.ac.jp [Department of Materials Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan)

    2016-03-01

    To simulate energetic neutron irradiation effects, yttria-stabilized zirconia (YSZ) which is one of the major materials for electrical corrosion potential sensors (ECP sensors) was irradiated with heavy ions at energies ranging from 7.3 MeV to 2.2 GeV. Ion irradiation effects on the lattice structure were analyzed using the X-ray diffraction (XRD). The increase in lattice constant was induced by the ion irradiation. It was dominated by the elastic collision process and not by the electronic excitation process. The lattice disordering which was observed as a broadening of XRD peaks was also induced by the irradiation especially for 200 MeV Xe ion irradiation. The present result suggests that the expansion and/or the disordering of YSZ lattice induced by energetic neutrons may affect the durability of a joint interface between a metal housing and YSZ membrane for the usage of ECP sensors in nuclear power reactors.

  3. Spin and isospin characteristics of the excited states of 36Ar through the reaction 32S(α,γ)36Ar in the bombarding energy range E/sub α/ = 4 to 5 MeV

    International Nuclear Information System (INIS)

    Chakrabarty, D.R.; Eswaran, M.A.; Ragoowansi, N.L.

    1983-01-01

    The α capture reaction 32 S(α,γ) 36 Ar was studied in the bombarding energy range of E/sub α/ = 4.13 to 5.00 MeV corresponding to the excitation energy range of E/sub x/ = 10.31 to 11.08 MeV in 36 Ar. Seven resonances have been located and their resonance strengths determined. Two of the resonances decay predominantly to the ground state while the other five decay predominantly to the first excited state of 36 Ar. Angular distribution measurements of the predominant decay gamma ray have been performed and the spin and parity of all the resonances assigned. The isospin of two of the resonances have been assigned as T = 0 while T = 1 has been assigned for three others. Evidence has been obtained for the operation of the isospin selection rule for the dipole (E1 and M1) and quadrupole (E2) gamma decay

  4. Cluster ion-surface interactions: from meV to MeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Nordlund, Kai; Meinander, Kristoffer; Jaervi, Tommi T.; Peltola, Jarkko; Samela, Juha [Accelerator Laboratory, University of Helsinki (Finland)

    2008-07-01

    The nature of cluster ion-surface interactions changes dramatically with the kinetic energy of the incoming cluster species. In this talk I review some of our recent work on the nature of cluster-surface interactions spanning an energy range from a few MeV/cluster to about 1 MeV/cluster and cluster sizes in the range of 10 - 1000 atoms/cluster. In the energy range of a few MeV/cluster ion, the kinetic energy of the incoming ion is insignificant compared to the energy gained when the surface potential energy at the cluster-surface interface is released and partly translated into kinetic energy. Even in this energy regime I show that surprisingly drastic effects can occur. When the energy of the incoming cluster is raised to a few eV/atom, the kinetic energy of the incoming cluster starts to affect the deposition. It will cause the cluster to entirely reform on impact. When the energy is raised to the range of keV's/cluster, the clusters start to penetrate the sample, fairly similar to conventional ion implantation. However, in dense targets the cluster ions may stick close to each other long enough to cause a significant enhancement of the heat spike in the material. Finally, I show that at kinetic energies around 1 MeV/cluster the cluster enhancement of the heat spike may lead to dramatic surface effects.

  5. MeV ion loss during 3He minority heating in TFTR

    International Nuclear Information System (INIS)

    Zweben, S.J.; Hammett, G.; Boivin, R.; Phillips, C.; Wilson, R.

    1992-01-01

    The loss of MeV ions during 3 He ICRH minority heating experiments has been measured using scintillator detectors near the wall of TFTR. The observed MeV ion losses to the bottom (90 degrees poloidal) detector are generally consistent with the expected first-orbit loss of D- 3 He alpha particle fusion products, with an inferred global reaction rate up to ∼10 16 reactions/sec. A qualitatively similar but unexpectedly large loss occurs 45 degrees poloidally below the outer midplane. This additional loss might be due to ICRH tail ions or to ICRH wave-induced loss of previously confined fusion products

  6. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, N.

    1979-01-01

    The surface damage of cold worked and annealed polycrystalline Nb irradiated at room temperature with He + ions sequentially at different energies over the range from 0.5 keV to 1.8 MeV has been investigated. The individual energy and the dose of the He + ion was chosen to match the theoretically calculated He + ion spectrum expected in the Tokamak T-20. In one set of irradiations, targets were irradiated at Kurchatov Institute starting with 0.5 keV 4 He + ions and extending up to 90 keV in eleven steps. Subsequently, the same area was irradiated at ANL starting at 150 keV and increased in eight steps up to 1.8 MeV. The irradiations were carried out for a total dose of 5.0 C/cm 2 . In another set of irradiations the sequence was reversed. Scanning electron microscopy results show formation of blisters and exfoliation. For the same dose the broad energy implant (due to sequential irradiation) appears to decrease the blister diameter and density as compared to irradiation with monoenergetic He + ions at a given energy (in the energy range considered). Some estimates of surface erosion yields due to blistering are given

  7. Energy and dose characteristics of ion bombardment during pulsed laser deposition of thin films under pulsed electric field

    International Nuclear Information System (INIS)

    Fominski, V.Yu.; Nevolin, V.N.; Smurov, I.

    2004-01-01

    Experiments on pulsed laser deposition of Fe films on Si substrates were performed with the aim to analyze the role of factors determining the formation of an energy spectrum and a dose of ions bombarding the film in strong pulsed electric fields. The amplitude of the high-voltage pulse (-40 kV) applied to the substrate and the laser fluence at the Fe target were fixed during the deposition. Owing to the high laser fluence (8 J/cm 2 ) at a relatively low power (20 mJ), the ionization of the laser plume was high, but the Fe vapor pressure near the substrate was low enough to avoid arcing. Electric signals from a target exposed to laser radiation were measured under different conditions (at different delay times) of application of electric pulses. The Si(100) substrates were analyzed using Rutherford ion backscattering/channeling spectrometry. The ion implantation dose occurred to be the highest if the high-voltage pulse was applied at a moment of time when the ion component of the plume approached the substrate. In this case, the implanted ions had the highest energy determined by the amplitude of the electric pulse. An advance or delay in applying a high-voltage pulse caused the ion dose and energy to decrease. A physical model incorporating three possible modes of ion implantation was proposed for the interpretation of the experimental results. If a laser plume was formed in the external field, ions were accelerated from the front of the dense plasma, and the ion current depended on the gas-dynamic expansion of the plume. The application of a high-voltage pulse, at the instant when the front approached the substrate, maintained the mode that was characteristic of the traditional plasma immersion ion implantation, and the ion current was governed by the dynamics of the plasma sheath in the substrate-to-target gap. In the case of an extremely late application of a high-voltage pulse, ions retained in the entire volume of the experimental chamber (as a result of the

  8. A comparative study of 30MeV boron4+ and 60MeV oxygen8+ ion irradiated Si NPN BJTs

    International Nuclear Information System (INIS)

    Kumar, M. Vinay; Krishnaveni, S.; Yashoda, T.; Dinesh, C. M.; Krishnakumar, K. S.; Jayashree, B.; Ramani

    2015-01-01

    The impact of 30MeV boron 4+ and 60MeV oxygen 8+ ion irradiation on electrical characteristics of 2N3773 Si NPN Bipolar junction transistors (BJTs) is reported in the present study. The transistors were decapped and irradiated at room temperature. Gummel characteristics, DC current gain and Capacitance-voltage (C-V) characteristics were studied before and after irradiation at different fluences. DC current gain has decreased significantly in both boron and oxygen ion irradiation. Also the value of capacitance decreased 3-4 times with increase in fluence. Both 30MeV boron ion and 60MeV oxygen ion induced similar extent of degradation in electrical characteristics of the transistor

  9. Transmission property and its applications of MeV ion beams with various capillaries

    International Nuclear Information System (INIS)

    Fujita, N; Ishii, K; Ogawa, H

    2012-01-01

    In order to clarify transmission properties of an ion beam extracted with various capillaries into the air, we have measured intensity distributions for the core and the halo components of MeV ion beams using various capillaries. In addition, we have performed in-air-RBS and in-air-PIXE from the point of the application. At the conference, progress report of transmission properties of ion beams with various capillaries and its applications will be presented.

  10. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range

    International Nuclear Information System (INIS)

    Vidovic, Z.

    1997-06-01

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H 0 , H 2 + and H 3 + projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H 2 + and H 3 + polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

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

    International Nuclear Information System (INIS)

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

    2016-01-01

    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. (paper)

  12. Influence of substrate pre-treatments by Xe{sup +} ion bombardment and plasma nitriding on the behavior of TiN coatings deposited by plasma reactive sputtering on 100Cr6 steel

    Energy Technology Data Exchange (ETDEWEB)

    Vales, S., E-mail: sandra.vales@usp.br [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Brito, P., E-mail: ppbrito@gmail.com [Pontifícia Universidade Católica de Minas Gerais (PUC-MG), Av. Dom José Gaspar 500, 30535-901 Belo Horizonte, MG (Brazil); Pineda, F.A.G., E-mail: pipe8219@gmail.com [Universidade de São Paulo (USP), Escola de Engenharia de São Carlos, Av. Trabalhador São Carlense 400, São Carlos, SP CEP 13566-590 (Brazil); Ochoa, E.A., E-mail: abigail_ochoa@hotmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Droppa, R., E-mail: roosevelt.droppa@ufabc.edu.br [Universidade Federal do ABC (UFABC), Av. dos Estados, 5001, Santo André, SP CEP 09210-580 (Brazil); Garcia, J., E-mail: jose.garcia@sandvik.com [Sandvik Coromant R& D, Lerkrogsvägen 19, SE-12680, Stockholm (Sweden); Morales, M., E-mail: monieriz@gmail.com [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); Alvarez, F., E-mail: alvarez@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campus Universitário Zeferino Vaz, Barão Geraldo, Campinas, SP CEP 13083-970 (Brazil); and others

    2016-07-01

    In this paper the influence of pre-treating a 100Cr6 steel surface by Xe{sup +} ion bombardment and plasma nitriding at low temperature (380 °C) on the roughness, wear resistance and residual stresses of thin TiN coatings deposited by reactive IBAD was investigated. The Xe{sup +} ion bombardment was carried out using a 1.0 keV kinetic energy by a broad ion beam assistance deposition (IBAD, Kaufman cell). The results showed that in the studied experimental conditions the ion bombardment intensifies nitrogen diffusion by creating lattice imperfections, stress, and increasing roughness. In case of the combined pre-treatment with Xe{sup +} ion bombardment and subsequent plasma nitriding, the samples evolved relatively high average roughness and the wear volume increased in comparison to the substrates exposed to only nitriding or ion bombardment. - Highlights: • Effect of Xe ion bombardment and plasma nitriding on TiN coatings was investigated. • Xe ion bombardment with 1.0 KeV increases nitrogen retention in plasma nitriding. • 1.0 KeV ion impact energy causes sputtering, thus increasing surface roughness. • TiN coating wear is minimum after plasma nitriding due to lowest roughness.

  13. M-subshell ionization of U by light-ion bombardment

    International Nuclear Information System (INIS)

    Jesus, A.P.; Ribeiro, J.P.

    1988-01-01

    M X-rays of U were produced by proton, deuteron and alpha-particle bombardment in the energy range of 0.20-1.00 MeV/u. N 6.7 →M 5 ((M subα)),N 6 →M 4 (M β ), N 5 →M 3 (M γ ), N 4 →M 2 and N 2 →M 1 line yields were obtained from a least-squares fit to the spectra and used to convert M X-ray production into M-subshell ionization cross sections. The uncertainty induced by the atomic parameters (X-ray fluorescence yields, Coster-Kronig and radiative transition rates) used in the conversion is discussed. The subshell ionization cross sections are then compared to PWBA values corrected for Coulomb deflection and energy loss according to Brandt and Lapicki, to the semiclassical theoretical values of Kocbach and to relativistic PWBA results, corrected for Coulomb and binding effects, of Chen et al. Intrashell transitions induced by the projectile and multiple ionization are suggested as causes of disagreement between theory and experiment, especially for alpha-particles. It is concluded that theory must go beyond the simple picture of the first-order pertubation approximation to explain M-subshell results and the care must be taken in the choice of wave functions. (author) [pt

  14. Measurements of secondary neutrons producted from thick targets bombarded by heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kurosawa, T.; Nakamura, T. [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center; Nakao, N.; Shibata, T.; Uwamino, Y.; Nakanishi, N.; Fukumura, A.; Kumamoto, Y.

    1997-03-01

    We measured neutron angular and energy distributions from high energy heavy ions stopping in targets of carbon, aluminum, copper and lead at HIMAC. These spectra are much harder for the lighter target nucleus like carbon. This means that the momentum transfer in the forward direction from heavy ion beam to lighter nuclei is much higher than that to heavier nuclei. (author)

  15. High-resolution Auger spectroscopy on 79 MeV Ar5+, 89 MeV Ar6+, and 136 MeV Ar7+ ions after excitation by helium

    International Nuclear Information System (INIS)

    Schneider, T.

    1988-01-01

    In this thesis the atomic structure of highly excited Ar 6+ and Ar 7+ ions was studied. For this 79 MeV Ar 5+ , 89 MeV Ar 6+ , and 136 MeV Ar 7+ ions of a heavy ion accelerator were excited by a He gas target to autoionizing states and the Auger electrons emitted in the decay were measured in highly-resolving state. The spectra were taken under an observational angle of zero degree relative to the beam axis in order to minimize the kinematical broadening of the Auger lines. (orig./HSI) [de

  16. Successive ionization of positive ions of carbon and nitrogen by electron bombardment

    International Nuclear Information System (INIS)

    Donets, E.D.; Ilyushchenko, V.I.

    Experimental studies of deep ionization of heavy ions are described. The applications of such studies in atomic physics, plasma physics and space physics are discussed. Investigations using intersecting ion-electron beams, shifted beams and ion trap sources are described, and data are presented for multi-charged ions of carbon, oxygen and nitrogen. A detailed description of the development of the IEL (electron beam ionizer) source, and the KRION (cryogenic version) source is given, and further data for the multiple ionization of carbon and nitrogen are given for charge states up to C 6+ and N 7+ . The advantages and disadvantages of the KRION source are discussed, and preliminary studies of a new torroidal ion trap source (HIRAC) are presented. (11 figs, 57 refs) (U.S.)

  17. MD simulation of atomic displacements in metals and metallic bilayers under low energy ion bombardment at 300 K

    International Nuclear Information System (INIS)

    Kornich, G.V.; Betz, G.; Bazhin, A.I.

    1999-01-01

    MD simulations of 100 eV Ar ion bombardment of (1 0 0) Ni and Al as well as Al/Ni bilayer crystals at 300 K have been performed and compared to previous calculations at 0 K. The Al/Ni bilayer crystal consisted of one Al layer on a (1 0 0) Ni substrate. Sputtering yields for Ni and Al/Ni show no temperature dependence, while for Al a pronounced increase with temperature was observed. The contributions of different mechanisms to the production of surface and bulk defects are discussed. The mean square displacement (MSD) of atoms is in all cases larger at 300 K as compared to 0 K. The larger MSD at 300 K is mainly due to an increase in lateral (perpendicular to the ion beam) motion of displaced atoms. Similar the number of atomic jumps, in which an atom leaves its original Wigner-Seitz cell, increases in all cases with temperature. For the pure elements the production of bulk vacancies and interstitials decreases with temperature, but the number of surface vacancies and ad-atoms increases with temperature. For the bilayer system practically no temperature dependence for defects was observed

  18. On the defect structure due to low energy ion bombardment of graphite

    Science.gov (United States)

    Marton, D.; Bu, H.; Boyd, K. J.; Todorov, S. S.; Al-Bayati, A. H.; Rabalais, J. W.

    1995-03-01

    Graphite surfaces cleaved perpendicular to the c axis have been irradiated with low doses of Ar + ions at 50 eV kinetic energy and perpendicular incidence. Scanning tunneling micrographs (STM) of these irradiated surfaces exhibited dome-like features as well as point defects. These dome-like features retain undisturbed graphite periodicity. This finding is attributed to the stopping of ions between the first and second graphite sheets. The possibility of doping semiconductors at extremely shallow depths is raised.

  19. The change of corrosion resistance of metals after bombardment by inert gas ions

    International Nuclear Information System (INIS)

    Vasil'ev, M.A.; Panarin, V.E.; Kosyachkov, A.A.

    2002-01-01

    Work functions of electrons and secondary ions of iron and oxygen from the surface of pure iron specimens pre-irradiated by argon ions were studied experimentally. One made use of the determined dependences in the experiments to passivate surface of low-carbon steel using the BULAT type commercial facilities. The designed extra device for those facilities ensured the required irradiation doses (equal to 10 17 atom x cm -2 ) resulting in improvement of steel corrosion resistance by several times [ru

  20. Short-range order in InSb amorphized under ion bombardment

    International Nuclear Information System (INIS)

    Pavlov, P.V.; Tetel'baum, D.I.; Gerasimov, A.I.

    1979-01-01

    The investigation of short-range order is carried out in polycrystal InSb films, irradiated with Ne + ions with E=150 keV and with the 2x10 15 ion/cm 2 dose. The data are obtained testifying to the film amorphization, the cause of which is the defect storage but not the local melting. Stability of the obtained amorphous phase at the room temperature is noted

  1. Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients

    International Nuclear Information System (INIS)

    Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W.

    1990-01-01

    The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, [M + H]+, or of alkali ions, [M + Na]+ and [M + 39K]+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX

  2. Depth distribution of damage in copper irradiated with MeV, Ni and He ions

    International Nuclear Information System (INIS)

    Narayan, J.; Noggle, T.S.; Oen, O.S.

    1975-01-01

    Transmission electron microscopy was used to study radiation damage as a function of depth caused by 58 and 4-MeV 58 Ni and 1-MeV He ions in copper single crystals at ambient temperature. The experimental damage density vs penetration depth distributions were compared with calculations based on the atomic collision theory of Lindhard et al. (LSS). For 58-MeV Ni ions, the calculated damage profile using the theoretical LSS value of the electronic stopping parameter (k = 0.167) agrees well with experiment. However, for 4-MeV Ni ions it is necessary to use k = 0.12 to get agreement with the experimental data. In the case of 1-MeV He, the depth location of the calculated damage peak is in good agreement with experiment when the electronic stopping determined by Chu and Powers is used whereas it is about 15 percent too close to the surface using the tables of Northcliffe and Schilling. (auth)

  3. Study of tapered glass capillary focusing MeV ion beam

    International Nuclear Information System (INIS)

    Gong Zhiyu; Yan Sha; Ma Hongji; Nie Rui; Xue Jianming; Wang Yugang

    2012-01-01

    In recent years, tapered glass capillary ion beam focusing is developing rapidly. It is attractive for simple, compact, low cost and easy use. However, the focusing mechanism for MeV ion beams is still indistinct. We present several experimental results of focusing 2 MeV He + beam. Ion beams were focused by tapered glass capillaries with various outlet inner diameters from several micron to hundred micron. The current densities, angle divergences and energy spectra of the transmitted ion beams are measured. The results proved that 2 MeV He + ions can focused and guided by our capillaries. The energy spectra show that a great part of transmitted ions experienced obvious energy loss, which is different from results of others research groups. We discussed the reason and charged it to the larger incident angle. Considered the incident ions with larger incident angle, the charge will distribute in a layer of micro meter depth in the capillary’s inner wall, but not the surface. The energy loss and many other spectra characters can be explained in this way.

  4. Secondary ions produced from condensed rare gas targets under highly charged MeV/amu heavy ion bombardment

    International Nuclear Information System (INIS)

    Tawara, H.; Tonuma, T.; Kumagai, H.; Matsuo, T.

    1994-01-01

    Secondary ions produced from condensed rare gas targets are observed under MeV/amu, highly charged, heavy ion impact. The intensities of the observed cluster ions decrease smoothly as the cluster sizes become large but show some discontinuities at particular sizes of cluster ions. This seems to be closely related to the stabilities of cluster ion structures. It is also noted that very few doubly charged or practically no triply/higher charged ions have been observed, in sharp contrast to that of some condensed molecular targets. (orig.)

  5. A comparison between the irradiation damage response of spinel and zirconia due to Xe ion bombardment

    International Nuclear Information System (INIS)

    Sickafus, K.E.; Wetteland, C.J.; Baker, N.P.; Yu Ning; Devanathan, R.; Nastasi, M.; Bordes, N.

    1998-01-01

    The mechanical properties of Xe-implanted spinel and cubic zirconia surfaces, as determined by nano-indentation measurements, are distinct and the differences can be related to their microstructures. Upon Xe 2+ ion irradiation to high dose at cryogenic temperature (120 K), the Young's modulus of irradiated spinel falls dramatically until the modulus is only about 3/4 the un-irradiated value. The maximum modulus occurs concurrent with the formation of a metastable crystalline phase of spinel. The subsequent elastic softening at higher Xe 2+ doses is an indication of the onset of amorphization of the spinel. Xe-implanted zirconia surfaces behave differently, in all cases showing almost no change in elastic modulus with increasing Xe 2+ ion dose. This is consistent with microstructural observations of Xe-implanted zirconia crystals which, unlike spinel, show no change in crystal structure with increasing ion dose. The hardness of both spinel and zirconia increases slightly for low Xe 2+ ion doses. At higher doses, zirconia shows little change in hardness, while the hardness of the implanted spinel falls by more than a factor of two. The initial increase in hardness of both spinel and zirconia is consistent with point defect accumulation and the precipitation of small interstitial clusters, while the drop in hardness of spinel at high Xe 2+ ion doses is due to the formation of an amorphous phase. (orig.)

  6. Effect of N4+ and C4+ ion beam bombardment on the optical and structural characteristics of ethylene-norbornene copolymer (TOPAS)

    International Nuclear Information System (INIS)

    Siljegovic, M.; Kacarevic-Popovic, Z.M.; Krkljes, A.N.; Stojanovic, Z.; Jovanovic, Z.M.

    2011-01-01

    Ion bombardment is a suitable tool to modify the optical properties of polymers. In the present study the effect of ion bombardment on the optical absorption of ethylene-norbornene copolymer (TOPAS) was studied using ultraviolet-visible (UV-Vis) and Raman spectroscopy. Polymer samples were bombarded with 60 keV C 4+ and N 4+ ion beams to various fluences ranging from 1.0 x 10 13 to 1.0 x 10 16 cm -2 . The indirect and direct band gaps have been determined. The values of direct band gaps have been found to be greater than the corresponding values of the indirect band gaps. Activation energy has been investigated as the function of ion fluences. The number of carbon atoms per conjugated length is determined according to modified Tauc's equation. The correlation between the optical band gap, activation energy for optical transition and the number of carbon atoms per conjugated length as well as chemical structure changes induced by ion beams irradiation have been discussed in the case of ethylene-norbornene copolymer.

  7. MeV ion-beam analysis of optical data storage films

    Science.gov (United States)

    Leavitt, J. A.; Mcintyre, L. C., Jr.; Lin, Z.

    1993-01-01

    Our objectives are threefold: (1) to accurately characterize optical data storage films by MeV ion-beam analysis (IBA) for ODSC collaborators; (2) to develop new and/or improved analysis techniques; and (3) to expand the capabilities of the IBA facility itself. Using H-1(+), He-4(+), and N-15(++) ion beams in the 1.5 MeV to 10 MeV energy range from a 5.5 MV Van de Graaff accelerator, film thickness (in atoms/sq cm), stoichiometry, impurity concentration profiles, and crystalline structure were determined by Rutherford backscattering (RBS), high-energy backscattering, channeling, nuclear reaction analysis (NRA) and proton induced X-ray emission (PIXE). Most of these techniques are discussed in detail in the ODSC Annual Report (February 17, 1987), p. 74. The PIXE technique is briefly discussed in the ODSC Annual Report (March 15, 1991), p. 23.

  8. Contrast of dry and water-saturated arabidopsis seeds irradiated by MeV energy ions

    International Nuclear Information System (INIS)

    Mei Tao; Qin Huaili; Xue Jianming; Wang Yugang

    2007-01-01

    The dry and water-saturated seeds of Arabidopsis thaliana were irradiated by H + ions with 6.5 MeV in atmosphere. The ion fluence used in this experiment was in the range of 4 x 10 9 -1 x 10 14 ions/cm 2 . According to the structure of the seed and TRIM simulation, the ions with the energy of 6.5 MeV can penetrate the whole seed. The experiment shows that the fluence-response curves for the dry seeds and water-saturated seeds had distinct shoulders and reduced rapidly. The experimental results show that the water-imbibed seeds were more sensitive than the dry seeds and the reason is from free radicals reaction. A model has been constructed, and primely simulates the experiment data. (authors)

  9. Amorphization and recrystallization in MeV ion implanted InP crystals

    International Nuclear Information System (INIS)

    Xiong, F.; Nieh, C.W.; Jamieson, D.N.; Vreeland, T. Jr.; Tombrello, T.A.

    1988-01-01

    A comprehensive study of MeV- 15 N-ion-implanted InP by a variety of analytical techniques has revealed the physical processes involved in MeV ion implantation into III-V compound semiconductors as well as the influence of post-implantation annealing. It provides a coherent picture of implant distribution, structural transition, crystalline damage, and lattice strain in InP crystals induced by ion implantation and thermal annealing. The experimental results from the different measurements are summarized in this report. Mechanisms of amorphization by implantation and recrystallization through annealing in MeV-ion-implanted InP are proposed and discussed in light of the results obtained

  10. Theoretical study of cylindrical energy analyzers for MeV range heavy ion beam probes

    International Nuclear Information System (INIS)

    Fujisawa, A.; Hamada, Y.

    1993-07-01

    A cylindrical energy analyzer with drift spaces is shown to have a second order focusing for beam incident angle when the deflection angle is properly chosen. The analyzer has a possibility to be applied to MeV range heavy ion beam probes, and will be also available for accurate particle energy measurements in many other fields. (author)

  11. Suppression of X-radiation from 2 MeV ion electrostatic accelerator

    International Nuclear Information System (INIS)

    Ignat'ev, I.G.; Miroshnichenko, V.I.; Sirenko, A.M.; Storizhko, V.E.

    2008-01-01

    The paper presents results concerning studies of X-radiation from 2 MeV ion electrostatic accelerator 'Sokol' used for nuclear microprobe analysis. The radiation protection system of the accelerator was developed and tested. Tests of the system of the accelerator show that it reduces doses rate by two orders of magnitude

  12. Effects of high-energy (MeV) ion implantation of polyester films

    International Nuclear Information System (INIS)

    Ueno, Keiji; Matsumoto, Yasuyo; Nishimiya, Nobuyuki; Noshiro, Mitsuru; Satou, Mamoru

    1991-01-01

    The effects of high-energy ion beam irradiation on polyester (PET) films using a 3 MeV tandem-type ion beam accelerator were studied. O, Ni, Pt, and Au as ion species were irradiated at 10 14 -10 15 ions/cm 2 on 50 μm thick PET films. Physical properties and molecular structure changes were studied by the surface resistivity measurements and RBS. The surface resistivity decreases with an increase in irradiation dose. At 10 15 ions/cm 2 irradiation, the surface resistivity is 10 8 Ω/□. According to RBS and XPS analyses, some carbon and oxygen atoms in the PET are replaced by implanted ions and the -C=O bonds are destroyed easily by the ion beam. (orig.)

  13. Secondary ion emission from metal surfaces bombarded by 0.5-10 keV protons and hydrogens

    International Nuclear Information System (INIS)

    Kitamura, Akira; Yano, Syukuro

    1978-01-01

    Secondary ion emission coefficients by bombardment of 0.5 - 10 keV protons K 11 and atomic hydrogens K 01 on copper, stainless steel, molybdenum and evaporated gold surfaces have been measured in a moderate vacuum. Results are summarized as follows; 1) There is no significant difference between K 11 and K 01 . 2) Differences in K 11 and K 11 between different samples of the same material and between the sample before baking-out and the same sample after baking-out are of the order of several tens of percent. 3) The incident particle energy E sub(max) at which K 11 and K 01 have the maximum value lies in the keV region, and increases with the target mass. According to the fact that E sub(max) differs substantially from the energy at which the elastic stopping power has the maximum value, a characteristic length l is introduced and calculated to be of the order of hundreds of A; the factor exp (-x/l) represents the degree of contribution of collision at depth x to K 11 or K 01 . (author)

  14. The influence of ion energy, target temperature, dose rate and crystal order on the shape of bombardment induced pyramids on copper crystals

    International Nuclear Information System (INIS)

    Tanovic, L.; Whitton, J.L.; Kofod, S.

    1978-01-01

    Following recent studies of energetic ion bombardment of copper, which established the conditions necessary for the production of cones/pyramids, investigations have been extended to include the effects of change in ion energy, target temperature and dose rate. In addition, the authors have attempted a detailed analysis of the influence of sample crystal orientation on the final form of pyramids and have investigated the stability of the pyramids as a function of the total dose. These experiments, as in earlier work, have been done using very pure copper, mass-analyzed ion beams and free of any metal contamination from, for example, defining apertures. (Auth.)

  15. Origin of Si(LMM) Auger Electron Emission from Silicon and Si-Alloys by keV Ar+ Ion Bombardment

    Science.gov (United States)

    Iwami, Motohiro; Kim, Su Chol; Kataoka, Yoshihide; Imura, Takeshi; Hiraki, Akio; Fujimoto, Fuminori

    1980-09-01

    Si(LMM) Auger electrons emitted from specimens of pure silicon and several Si-alloys (Ni-Si, Pd-Si and Cu-Si) under keV Ar+ ion bombardment, were examined. In the Auger spectra from all specimens studied there were four peaks at energies of 92, 86, 76 and 66 eV. The Auger signal intensity varied considerably with both the incident angle and the energy of the primary ion beam. It is proposed that the Auger electrons are emitted from silicon atoms (or ions) just beneath the specimen surface but free from the bulk network.

  16. Origin of Si(LMM) Auger electron emission from silicon and Si-alloys by keV Ar/sup +/ ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Iwami, M; Kim, S; Kataoka, Y; Imura, T; Hiraki, A [Osaka Univ., Suita (Japan). Faculty of Engineering

    1980-09-01

    Si(LMM) Auger electrons emitted from specimens of pure silicon and several Si-alloys (Ni-Si, Pd-Si and Cu-Si) under keV Ar/sup +/ ion bombardment, were examined. In the Auger spectra from all specimens studied there were four peaks at energies of 92, 86, 76 and 66 eV. The Auger signal intensity varied considerably with both the incident angle and the energy of the primary ion beam. It is proposed that the Auger electrons are emitted from silicon atoms (or ions) just beneath the specimen surface but free from the bulk network.

  17. Secondary ion yield changes in Si and GaAs due to topography changes during O+2 or Cs+ ion bombardment

    International Nuclear Information System (INIS)

    Stevie, F.A.; Kahora, P.M.; Simons, D.S.; Chi, P.

    1988-01-01

    Changes in secondary ion yields of matrix and dopant species have been correlated with changes in surface topography during O + 2 bombardment of Si and GaAs. In Si, profiles were measured in (100) wafers at 6- and 8-keV impact energy. At 6 keV, a yield increase of about 70% occurred for Si + over a depth range of 2.5 to 3.5 μm, with changes in other species ranging from a decrease of ∼20% for Si + 3 to an increase of more than 25% for O + . The development of a rippled surface topography was observed in scanning electron micrographs over the same depth range. Similar effects occurred over a 3--5 μm depth range for 8-keV ions, and in (111) silicon at a depth of 3 to 4 μm for 6-keV ions. No differences were noted between p- and n-type silicon, or implanted and unimplanted silicon. In GaAs, profiles were measured in (100) wafers at 2.5-, 5.5-, and 8-keV impact energies. At 8 keV, a yield increase of about 70% was found for GaO + in the range 0.6--1.0 μm, with smaller changes for other matrix species. At 5.5 keV, similar effects were observed, but over a depth interval of 0.3 to 0.7 μm. No yield changes were detected at 2.5-keV impact energy. The yield changes at the higher energies were again correlated with the onset of changes in topography. No change in ion yield or surface topography was noted for Cs + bombardment of Si or GaAs. The topography and ion yield changes are affected by the angle of incidence and, for Si, the oxygen coverage. The results show that the practice of normalizing secondary ion mass spectrometry dopant profiles to a matrix signal must be modified for situations where matrix yield changes occur

  18. Energy loss and straggling of MeV ions through biological samples

    International Nuclear Information System (INIS)

    Ma Lei; Wang Yugang; Xue Jianming; Chen Qizhong; Zhang Weiming; Zhang Yanwen

    2007-01-01

    Energy loss and energy straggling of energetic ions through natural dehydrated biological samples were investigated using transmission technique. Biological samples (onion membrane, egg coat, and tomato coat) with different mass thickness were studied, together with Mylar for comparison. The energy loss and energy straggling of MeV H and He ions after penetrating the biological and Mylar samples were measured. The experimental results show that the average energy losses of MeV ions through the biological samples are consistent with SRIM predictions; however, large deviation in energy straggling is observed between the measured results and the SRIM predictions. Taking into account inhomogeneity in mass density and structure of the biological sample, an energy straggling formula is suggested, and the experimental energy straggling values are well predicted by the proposed formula

  19. Development of an MeV ion beam lithography system in Jyvaeskylae

    Energy Technology Data Exchange (ETDEWEB)

    Gorelick, Sergey [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland)]. E-mail: Sergey.Gorelick@phys.jyu.fi; Ylimaeki, Tommi [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Sajavaara, Timo [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Laitinen, Mikko [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Sagari, A.R.A. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland); Whitlow, Harry J. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FIN-40014 (Finland)

    2007-07-15

    A lithographic facility for writing patterns with ion beams from cyclotron beams is under development for the Jyvaeskylae cyclotron. Instead of focusing and deflecting the beam with electrostatic and magnetic fields a different approach is used. Here a small rectangular beam spot is defined by the shadow of a computer-controlled variable aperture in close proximity to the sample. This allows parallel exposure of rectangular pattern elements of 5-500 {mu}m side with protons up to 6 MeV and heavy ions ({sup 20}Ne, {sup 85}Kr) up to few 100 MeV. Here we present a short overview of the system under construction and development of the aperture design, which is a critical aspect for all ion beam lithography systems.

  20. Surface structural determination of UO2(111) using MeV ions

    International Nuclear Information System (INIS)

    Thompson, K.A.; Ellis, W.P.; Taylor, T.N.; Valone, S.M.; Maggiore, C.J.

    1983-01-01

    The UO 2 (111) surface was studied using MeV ions incident along the and directions. In addition, this surface was well characterized by LEED and Auger analysis. A resonance at 3.05 MeV for 4 He elastic scattering from 16 O made it possible to study the surface peaks for uranium and oxygen simultaneously. By combining previous surface studies with detailed analysis of the surface peaks and rocking curves for this compound material, an outward relaxation of 0.19 A +- 0.01 A was determined for uranium

  1. 120 MeV Ag ion induced effects in Au/HfO2/Si MOSCAPs

    Science.gov (United States)

    Manikanthababu, N.; Prajna, K.; Pathak, A. P.; Rao, S. V. S. Nageswara

    2018-05-01

    HfO2/Si thinfilms were deposited by RF sputtering technique. 120 MeV Ag ion irradiation has been used to study the electrical properties of Au/HfO2/Si MOSCAPs. SHI (120 MeV Ag) induced annealing, defects creation and intermixing effects on the electrical properties of these systems have been studied. Here, we have observed that the high electronic excitation can cause a significant reduction of leakage currents in these MOSCAP devices. Various quantum mechanical tunneling phenomenon has been observed from the I-V characteristics.

  2. Moessbauer of phase separation in FeNi multilayers under ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, L.; Paesano, A.; Brueckman, M.E. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Scorzelli, R.B.; Dominguez, A.B. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Shinjo, T.; Ono, T.; Hosoito, N. [Kyoto Univ. (Japan). Inst. for Chemical Research

    1997-01-01

    We investigated the effect of noble gas irradiation (He, Ne, Ar and Xe) on the Fe-Ni multilayers with a very thin modulation and nominal composition in the invar region Fe{sub 0.63} Ni{sub 0.37}. The evaluation of the formation/stability of the Fe-Ni phases formed under irradiation with different ions and doses was followed by conversion electron Moessbauer spectroscopy (CEMS). (author). 21 refs., 4 figs., 2 tabs.; e-mail: scorza at novell.cat.cbpf.br.

  3. Study of beryllium redeposition under bombardment by high intensity -low energy- hydrogen ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Gureev, V.M.; Guseva, M.I.; Danelyan, L.S. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)] [and others

    1998-01-01

    The results of studying the erosion of beryllium under an effect of intense ion fluxes with the energy of 250 eV, at the fluences {approx}10{sup 2}1 cm{sup -2}, at the MAGRAS-stand are given. The operating conditions under which a practically-complete redeposition of the sputtered beryllium upon the target surface were experimentally-realized. A change in the microstructure of a beryllium target under sputtering and redeposition is analyzed. Some technological applications are considered. (author)

  4. Thin film adhesion modification by MeV ions

    International Nuclear Information System (INIS)

    Sugden, S.

    1991-08-01

    The adhesion of thin films, and in particular the way in which such adhesion may be improved by irradiation, is rather poorly understood. The radiation enhanced adhesion effect has been investigated through the use of Ultra High Vacuum sample preparation, analysis and irradiation techniques, in order to gain control over surface and interface composition. In the systems studied, Au on Ta, Au on Si and Ag on Si, films deposited on atomically clean surfaces show good adhesion, and no evidence of enhancement due to irradiation is observed in the case of such clean interfaces. The results are entirely consistent with radiation enhanced adhesion being due to radiolytic effects on contaminant containing layers at the film/substrate interface. In addition, on silicon substrates the observations highlight the superiority of thermal cleaning over low energy sputtering as a route for producing a clean surface. A model of the radiation enhanced adhesion observations for dirty interface systems is developed, which takes into account the two dimensional nature of the ion energy deposition process. All the observations on such systems are broadly consistent with an activation energy for the process of approximately 5 eV. This value is sufficiently large to bring about chemical bonding rearrangement at the critical film/substrate interface. (Author)

  5. Silicide formation by Ar/sup +/ ion bombardment of Pd/Si

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R Y; Whang, C N; Kim, H K; Smith, R J

    1988-08-01

    Palladium films, 45 nm thick, evaporated on to Si(111) were irradiated to various doses with 78 keV Ar/sup +/ ions to promote silicide formation. Rutherford backscattering spectroscopy (RBS) shows that intermixing has occurred across the Pd/Si interface at room temperature. The mixing behaviour is increased with dose which coincides well with the theoretical model of cascade mixing. The absence of deep RBS tails for palladium and the small area of this for silicon spectra indicate that short-range mixing occurs. From the calculated damage profiles computed with TRIM code, the dominant diffusion species is found to be silicon atoms in the Pd/Si system. It is also found that the initial compound formed by Ar/sup +/ irradiation is Pd/sub 2/Si which increases with dose. At a dose of 1 x 10/sup 16/ Ar/sup +/ cm/sup -2/, a 48 nm thickness of Pd/sub 2/Si was formed by ion-beam mixing at room temperature.

  6. Reducing the impurity incorporation from residual gas by ion bombardment during high vacuum magnetron sputtering

    International Nuclear Information System (INIS)

    Rosen, Johanna; Widenkvist, Erika; Larsson, Karin; Kreissig, Ulrich; Mraz, Stanislav; Martinez, Carlos; Music, Denis; Schneider, J. M.

    2006-01-01

    The influence of ion energy on the hydrogen incorporation has been investigated for alumina thin films, deposited by reactive magnetron sputtering in an Ar/O 2 /H 2 O environment. Ar + with an average kinetic energy of ∼5 eV was determined to be the dominating species in the plasma. The films were analyzed with x-ray diffraction, x-ray photoelectron spectroscopy, and elastic recoil detection analysis, demonstrating evidence for amorphous films with stoichiometric O/Al ratio. As the substrate bias potential was increased from -15 V (floating potential) to -100 V, the hydrogen content decreased by ∼70%, from 9.1 to 2.8 at. %. Based on ab initio calculations, these results may be understood by thermodynamic principles, where a supply of energy enables surface diffusion, H 2 formation, and desorption [Rosen et al., J. Phys.: Condens. Matter 17, L137 (2005)]. These findings are of importance for the understanding of the correlation between ion energy and film composition and also show a pathway to reduce impurity incorporation during film growth in a high vacuum ambient

  7. Ion desorption from solid surfaces under slow (KeV) and fast (MeV) ion sputtering. Influence of the charge state and of the incidence angle on the input channel

    International Nuclear Information System (INIS)

    Joret, H.

    1990-06-01

    Solid surfaces of organic and inorganic materials have been bombarded by fast heavy ions (several MeV). It is shown that the charge state of the projectile has a strong influence on the atomic and molecular ion desorption yield. Experimental studies proved that molecular ions can be emitted intact from deep layers underneath the surface (volume emission) with the existence of a crater emission. On the other hand light ions like H(+), H(+)-2, H(+)-3 are emitted from the surface of the solid in a time around 10 -16 second. The H(+) depends on the incident charge state g-i. When using slow ions (keV) the same dependence was observed for the first time and compared to the fast ion results. The equilibrum charge state of fast ions passing through solids was measured. The influence of the angle of incidence was investigated. Langmuir-Blodgett films of fatty acid were used. A geometrical model is developed for the 50 angstroms layer [fr

  8. Nucleation of diamond by pure carbon ion bombardment--a transmission electron microscopy study

    International Nuclear Information System (INIS)

    Yao, Y.; Liao, M.Y.; Wang, Z.G.; Lifshitz, Y.; Lee, S.

    2005-01-01

    A cross-sectional high-resolution transmission electron microscopy (HRTEM) study of a film deposited by a 1 keV mass-selected carbon ion beam onto silicon held at 800 deg. C is presented. Initially, a graphitic film with its basal planes perpendicular to the substrate is evolving. The precipitation of nanodiamond crystallites in upper layers is confirmed by HRTEM, selected area electron diffraction, and electron energy loss spectroscopy. The nucleation of diamond on graphitic edges as predicted by Lambrecht et al. [W. R. L. Lambrecht, C. H. Lee, B. Segall, J. C. Angus, Z. Li, and M. Sunkara, Nature, 364 607 (1993)] is experimentally confirmed. The results are discussed in terms of our recent subplantation-based diamond nucleation model

  9. Nonlinear Amplitude Evolution During Spontaneous Patterning of Ion-Bombarded Si(001)

    International Nuclear Information System (INIS)

    Chason, Eric; Erlebacher, Jonah; Aziz, Michael J.; Floro, Jerold A.; Sinclair, Michael B.

    1999-01-01

    The time evolution of the amplitude of periodic nanoscale ripple patterns formed on Ar+ sputtered Si(OOl ) surfaces was examined using a recently developed in situ spectroscopic technique. At sufficiently long times, we find that the amplitude does not continue to grow exponentially as predicted by the standard Bradley-Harper sputter rippling model. In accounting for this discrepancy, we rule out effects related to the concentration of mobile species, high surface curvature, surface energy anisotropy, and ion-surface interactions. We observe that for all wavelengths the amplitude ceases to grow when the width of the topmost terrace of the ripples is reduced to approximately 25 nm. This observation suggests that a short circuit relaxation mechanism limits amplitude . growth. A strategy for influencing the ultimate ripple amplitude is discussed

  10. Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vorlíček, Vladimír; Dejneka, Alexandr; Chvostová, Dagmar; Jäger, Aleš; Vacík, Jiří; Jastrabík, Lubomír; Naramoto, H.; Narumi, K.

    2013-01-01

    Roč. 98, SI (2013), s. 49-55 ISSN 0042-207X R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : energetic cluster s * silicon * surface modification * amorphization * nanostructure * Raman scattering * ion channeling Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 1.426, year: 2013 http://ac.els-cdn.com/S0042207X13001759/1-s2.0-S0042207X13001759-main.pdf?_tid=04e9c946-21dd-11e3-b076-00000aacb361&acdnat=1379672070_859355b2850a09ac74bc8ff413e35dda

  11. Application of alpha spectrometry to the discovery of new elements by heavy-ion-beam bombardment

    International Nuclear Information System (INIS)

    Nitschke, J.M.

    1983-05-01

    Starting with polonium in 1898, α-spectrometry has played a decisive role in the discovery of new, heavy elements. For even-even nuclei, α-spectra have proved simple to interpret and exhibit systematic trends that allow extrapolation to unknown isotopes. The early discovery of the natural α-decay series led to the very powerful method of genetically linking the decay of new elements to the well-established α-emission of daughter and granddaughter nuclei. This technique has been used for all recent discoveries of new elements including Z = 109. Up to mendelevium (Z = 101), thin samples suitable for α-spectrometry were prepared by chemical methods. With the advent of heavy-ion accelerators new sample preparation methods emerged. These were based on the large momentum transfer associated with heavy-ion reactions, which produced energetic target recoils that, when ejected from the target, could be thermalized in He gas. Subsequent electrical deposition or a He-jet technique yielded samples that were not only thin enough for α-spectroscopy, but also for α- and #betta#-recoil experiments. Many variations of these methods have been developed and are discussed. For the synthesis of element 106 an aerosol-based recoil transport technique was devised. In the most recent experiments, α-spectrometry has been coupled with the magnetic analysis of the recoils. The time from production to analysis of an isotope has thereby been reduced to 10 - 6 s; while it was 10 - 1 to 10 0 s for He-jets and 10 1 to 10 3 s for rapid chemical separations. Experiments are now in progress to synthesize super heavy elements (SHE) and to analyze them with these latest techniques. Again, α-spectrometry will play a major role since the expected signature for the decay of a SHE is a sequence of α-decays followed by spontaneous fission

  12. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Science.gov (United States)

    Rupprechter, G.; Kaichev, V. V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V. I.

    2004-07-01

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H 2 mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH xO species as precursors for CO bond cleavage and that the formation of CH xO is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  13. CO dissociation and CO hydrogenation on smooth and ion-bombarded Pd(1 1 1): SFG and XPS spectroscopy at mbar pressures

    Energy Technology Data Exchange (ETDEWEB)

    Rupprechter, G.; Kaichev, V.V.; Unterhalt, H.; Morkel, M.; Bukhtiyarov, V.I

    2004-07-31

    The CO dissociation probability on transition metals is often invoked to explain the product distribution (selectivity) of catalytic CO hydrogenation. Along these lines, we have investigated CO adsorption and dissociation on smooth and ion-bombarded Pd(1 1 1) at pressures up to 1 mbar using vibrational sum frequency generation (SFG) and X-ray photoelectron spectroscopy (XPS). Under high pressure, CO adsorbate structures were observed that were identical to high-coverage structures in UHV. On ion-bombarded surfaces an additional species was detected which was attributed to CO bridge bonded to defect (low-coordinated) sites. On both surfaces, no indications of CO dissociation were found even after hours of 0.1 mbar CO exposure. However, exposing CO/H{sub 2} mixtures to ion-bombarded Pd(1 1 1) produced carbonaceous deposits suggesting CH{sub x}O species as precursors for C---O bond cleavage and that the formation of CH{sub x}O is facilitated by surface defects. The relevance of the observations for CO hydrogenation on Pd catalysts is discussed.

  14. STIM with energy loss contrast: An imaging modality unique to MeV ions

    International Nuclear Information System (INIS)

    Lefevre, H.W.; Schofield, R.M.S.; Bench, G.S.; Legge, G.J.F.

    1991-01-01

    Scanning transmission ion microscopy (STIM) through measurement of energy loss of individual ions is a quantitative imaging technique with several unique capabilities. The uniqueness derives conjointly from the large penetration with small scattering of MeV ions in low-Z specimens, from the simple relationship between energy loss and projected or areal density, and from the almost 100% efficiency with which one obtains pixel data from individual ions. Since contrast is in energy loss and not in numbers of events, the statistics of energy loss straggling affects the image but the statistics of counting does not. Small scattering makes it possible to observe details within transparent specimens. High efficiency makes it possible to collect large data sets for computed tomography, stereo, or high-definition imaging with a small radiation dose. High efficiency allows one to minimize aberrations by use of small apertures, to achieve good precision in the determination of areal density, or even to image live biological specimens in air since only one or a few ions per pixel are required. This paper includes a bibliography on STIM with MeV ions, it discusses the accuracy that one can achieve in the areal density coloring of a pixel with data from one or a few ions, and it supplements that review with recent examples from the Melbourne and the Eugene microprobes. (orig.)

  15. Measurement of neutron spectra generated from bombardment of 4 to 24 MeV protons on a thick 9Be target and estimation of neutron yields

    International Nuclear Information System (INIS)

    Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P.; Sunil, C.; Bandyopadhyay, T.; Sharma, S. C.; Ramjilal,; Ninawe, N. G.; Gupta, A. K.

    2014-01-01

    A systematic study on the measurement of neutron spectra emitted from the interaction of protons of various energies with a thick beryllium target has been carried out. The measurements were carried out in the forward direction (at 0° with respect to the direction of protons) using CR-39 detectors. The doses were estimated using the in-house image analyzing program autoTRAK-n, which works on the principle of luminosity variation in and around the track boundaries. A total of six different proton energies starting from 4 MeV to 24 MeV with an energy gap of 4 MeV were chosen for the study of the neutron yields and the estimation of doses. Nearly, 92% of the recoil tracks developed after chemical etching were circular in nature, but the size distributions of the recoil tracks were not found to be linearly dependent on the projectile energy. The neutron yield and dose values were found to be increasing linearly with increasing projectile energies. The response of CR-39 detector was also investigated at different beam currents at two different proton energies. A linear increase of neutron yield with beam current was observed

  16. Investigation of (n, 2n) reaction and fission rates in iron-shielded uranium samples bombarded by 14.9 MeV neutrons

    International Nuclear Information System (INIS)

    Shani, G.

    1976-01-01

    The effect of the thickness of iron shielding on the (n, 2n) reaction rate in a fusion reactor (hybrid) blanket is investigated. The results are compared with the fission rate-dependence. Samples of natural uranium are irradiated with 14 MeV neutrons, with iron slabs of various thickness between the neutron generator target and the samples. Both reactions are threshold reactions but the fact that the 238 U (n, 2n) reaction threshold is at 6 MeV and that of fission is at 2 MeV makes the ratio between the two very much geometry-dependent. Two geometrical effects take place, the 1/r 2 and the build-up. While the build-up affects the (n, 2n) reaction rate, the fission rate is affected more by the 1/r 2 effect. The reason is that both elastic and inelastic scattering end up with neutrons with energy above fission threshold, while only elastic scattering brings high energy neutrons to the sample and causes (n, 2n) reaction. A comparison is made with calculated results where the geometrical effects do not exist. (author)

  17. Directional effect on coloration in LiF crystal by H{sup +} and H{sub 2}{sup +} ion bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Mingle, Gan; Naramoto, Hiroshi; Aoki, Yasushi; Yamamoto, Shunya; Jianer, Zeng; Takeshita, Hidefumi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    In the present paper, the first results are reported about the coloration in LiF crystals induced by bombardments of single hydrogen ions (H{sup +}) and molecular hydrogen ions (H{sub 2}{sup +}) with the same velocity under the <100> aligned and random conditions. For the single hydrogen ion irradiation, the coloration is rather simple. The F-type color center absorption under the <100> aligned condition becomes larger than that under the random condition with the dose increase because of larger fraction of electronic energy loss under channeling condition. On the contrary, the coloration for the molecular ions does not show big channeling effect. In the low dose region some difference can be seen but the difference of coloration is not observed any more with the dose increase. The pronounced coloration for molecular ions under the channeling condition is observed in comparison with that for single ions. (author)

  18. Influence of ion bombardment on structural and electrical properties of SiO2 thin films deposited from O2/HMDSO inductively coupled plasmas under continuous wave and pulsed modes

    International Nuclear Information System (INIS)

    Bousquet, A.; Goullet, A.; Leteinturier, C.; Granier, A.; Coulon, N.

    2008-01-01

    Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO 2 -like film deposited from oxygen/hexa-methyl-di-siloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment. (authors)

  19. Experimental and theoretical studies of bombardment induced surface morphology changes

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.; Williams, J.S.

    1980-01-01

    In this review results of experimental and theoretical studies of solid surface morphology changes due to ion bombardment are discussed. An attempt is undertaken to classify the observed specific features of a structure, generated by ion bombardment [ru

  20. Vacancy production in molybdenum by low energy light ion bombardment: computer simulation

    International Nuclear Information System (INIS)

    Hou, M.; Veen, A. van; Caspers, L.M.; Ypma, M.R.

    1983-01-01

    A comparison is made of the room temperature vacancy production measured with THDS (thermal helium desorption spectrometry) and the Frenkel pair production calculated in the binary collision approximation with MARLOWE for 0.5 to 3 keV He + ions and 1.5 keV protons injected into a Mo(110) crystal. Using the distributions of Frenkel pair separation distances calculated with MARLOWE for various values of the displacement threshold Esub(d), the experimental data are matched by selecting a cut-off radius Rsub(c) so that for separations larger than Rsub(c) the Frenkel pairs survive recombination. It became apparent that all experimental data could be reasonably described by a pair of parameters Esub(d) = 33 eV and Rsub(c) = 3.7 a 0 (a 0 is the lattice cell edge unit). The value of Esub(d) we found is close to the experimentally determined threshold energy for permanent displacements in Mo. A detailed analysis of the recombination process using the MARLOWE results shows that the found cut-off radius corresponds with an effective recombination radius Rsub(o) = 2.8 a 0 . In the literature lower (theoretical) values of Rsub(o) = 1.4 - 2.1 a 0 are quoted for correlated recombination of single Frenkel pairs in molybdenum. (orig.)

  1. Ion shaking in the 200 MeV XLS-ring

    International Nuclear Information System (INIS)

    Bozoki, E.; Kramer, S.L.

    1992-01-01

    It has been shown that ions, trapped inside the beam's potential, can be removed by the clearing electrodes when the amplitude of the ion oscillation is increased by vertically shaking the ions. We will report on a similar experiment in the 200 Mev XLS ring. The design of the ion clearing system for the ring and the first results obtained, were already reported. In the present series of experiments, RF voltage was applied on a pair of vertical strip-lines. The frequency was scanned in the range of the ion (from H 2 to CO 2 ) bounce frequencies in the ring (1--10 MHz). The response of the beam size, vertical betatron tune and lifetime was studied

  2. Accelerator based synthesis of hydroxyapatite by MeV ion implantation

    International Nuclear Information System (INIS)

    Rautray, Tapash R.; Narayanan, R.; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-01-01

    Accelerator based MeV ion implantation of Ca 2+ and P 2+ into the titanium substrate to form hydroxyapatite (HA) has been carried out. Calcium hydroxide was formed after heating the calcium implanted titanium in air at 80 o C for 3 h. Upon subsequent annealing for 5 min at 600 o C HA was formed on the surface. Penetration depth of the HA layer in this method is much higher as compared to keV ion implantation. By elemental analysis, Ca/P ratio of the HA was found to be 1.76 which is higher than the ideal 1.67. This higher Ca/P ratio is attributed to the higher penetration depth of the MeV technique used.

  3. Changes of electronic properties of p-GaN(0 0 0 1) surface after low-energy N+-ion bombardment

    Science.gov (United States)

    Grodzicki, M.; Mazur, P.; Ciszewski, A.

    2018-05-01

    The p-GaN(0 0 0 1) crystal with a relatively low acceptor concentration of 5 × 1016 cm-3 is used in these studies, which are carried out in situ under ultrahigh vacuum (UHV) by ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED). The p-GaN(0 0 0 1)-(1 × 1) surface is achieved by thermal cleaning. N+-ion bombardment by a 200 eV ion beam changes the surface stoichiometry, enriches it with nitrogen, and disorders it. Such modified surface layer inverts its semiconducting character from p- into n-type. The electron affinity for the already cleaned p-GaN surface and that just after bombardment shows a shift from 2.2 eV to 3.2 eV, as well as an increase of band bending at the vacuum/surface interface from 1.4 eV to 2.5 eV. Proper post-bombardment heating of the sample restores the initial atomic order of the modified layer, leaving its n-type semiconducting character unchanged. The results of the measurements are discussed based on two types of surface states concepts.

  4. Charge collection efficiency degradation induced by MeV ions in semiconductor devices: Model and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Vittone, E., E-mail: ettore.vittone@unito.it [Department of Physics, NIS Research Centre and CNISM, University of Torino, via P. Giuria 1, 10125 Torino (Italy); Pastuovic, Z. [Centre for Accelerator Science (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2234 (Australia); Breese, M.B.H. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Garcia Lopez, J. [Centro Nacional de Aceleradores (CNA), Sevilla University, J. Andalucia, CSIC, Av. Thomas A. Edison 7, 41092 Sevilla (Spain); Jaksic, M. [Department for Experimental Physics, Ruder Boškovic Institute (RBI), P.O. Box 180, 10002 Zagreb (Croatia); Raisanen, J. [Department of Physics, University of Helsinki, Helsinki 00014 (Finland); Siegele, R. [Centre for Accelerator Science (ANSTO), Locked bag 2001, Kirrawee DC, NSW 2234 (Australia); Simon, A. [International Atomic Energy Agency (IAEA), Vienna International Centre, P.O. Box 100, 1400 Vienna (Austria); Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Vizkelethy, G. [Sandia National Laboratories (SNL), PO Box 5800, Albuquerque, NM (United States)

    2016-04-01

    Highlights: • We study the electronic degradation of semiconductors induced by ion irradiation. • The experimental protocol is based on MeV ion microbeam irradiation. • The radiation induced damage is measured by IBIC. • The general model fits the experimental data in the low level damage regime. • Key parameters relevant to the intrinsic radiation hardness are extracted. - Abstract: This paper investigates both theoretically and experimentally the charge collection efficiency (CCE) degradation in silicon diodes induced by energetic ions. Ion Beam Induced Charge (IBIC) measurements carried out on n- and p-type silicon diodes which were previously irradiated with MeV He ions show evidence that the CCE degradation does not only depend on the mass, energy and fluence of the damaging ion, but also depends on the ion probe species and on the polarization state of the device. A general one-dimensional model is derived, which accounts for the ion-induced defect distribution, the ionization profile of the probing ion and the charge induction mechanism. Using the ionizing and non-ionizing energy loss profiles resulting from simulations based on the binary collision approximation and on the electrostatic/transport parameters of the diode under study as input, the model is able to accurately reproduce the experimental CCE degradation curves without introducing any phenomenological additional term or formula. Although limited to low level of damage, the model is quite general, including the displacement damage approach as a special case and can be applied to any semiconductor device. It provides a method to measure the capture coefficients of the radiation induced recombination centres. They can be considered indexes, which can contribute to assessing the relative radiation hardness of semiconductor materials.

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  6. 130 MeV Au ion irradiation induced dewetting on In2Te3 thin film

    International Nuclear Information System (INIS)

    Matheswaran, P.; Abhirami, K.M.; Gokul, B.; Sathyamoorthy, R.; Prakash, Jai; Asokan, K.; Kanjilal, D.

    2012-01-01

    Highlights: ► In 2 Te 3 phase formed from In/Te bilayer by 130 MeV Au ion irradiation. ► Lower fluence results mixed phases with initial state of dewetting. ► At higher fluence, In 2 Te 3 phase with complete dewetting pattern is formed. ► Thermal spike model is used to explain the inter face mixing phenomena. ► SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 × 10 13 ions/cm 2 . At the higher fluence of 3 × 10 13 ions/cm 2 , dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

  7. GXRD study of 100 MeV Fe9+ ion irradiated indium phosphide

    International Nuclear Information System (INIS)

    Dubey, R.L.; Dubey, S.K.; Kachhap, N.K.; Kanjilal, D.

    2014-01-01

    Swift heavy ions with MeV to GeV kinetic energy offer unique possibilities of modifying material properties. Each projectile passing through the target material causes loss of its energy by ion-electrons and ion-atoms interaction with the target material. The consequence of formal one is to change in surface properties and latter to produces damage deep in the target material near the projected range of projectile. In the present work, indium phosphide samples were irradiated at 100 MeV 56 Fe 9+ ions with different fluences varying from 1x10 12 to 1x10 14 ions cm -2 using the 15UD Pelletron facilities at Inter University Accelerator Centre (IUAC), New Delhi. Grazing angle X-ray diffraction technique was used to investigate the structural properties of irradiated indium phosphide at different depths. The GXRD spectra of non-irradiated and irradiated samples were recorded at different grazing angle i.e 1°, 2°, 3°, 4° and 5° to get the structural information over the projected range. The detailed result will be presented and discussed in the conference. (author)

  8. The emittance and brightness characteristics of negative ion sources suitable for MeV ion implantation

    International Nuclear Information System (INIS)

    Alton, G.D.

    1987-01-01

    This paper provides the description and beam properties of ion sources suitable for use with ion implantation devices. Particular emphasis is placed on the emittance and brightness properties of state-of-the-art, high intensity, negative ion sources based on the cesium ion sputter principle

  9. Imaging of single cells and tissue using MeV ions

    International Nuclear Information System (INIS)

    Watt, F.; Bettiol, A.A.; Kan, J.A. van; Ynsa, M.D.; Ren Minqin; Rajendran, R.; Cui Huifang; Sheu, F.-S.; Jenner, A.M.

    2009-01-01

    With the attainment of sub-100 nm high energy (MeV) ion beams, comes the opportunity to image cells and tissue at nano-dimensions. The advantage of MeV ion imaging is that the ions will penetrate whole cells, or relatively thick tissue sections, without any significant loss of resolution. In this paper, we demonstrate that whole cells (cultured N2A neuroblastoma cells ATCC) and tissue sections (rabbit pancreas tissue) can be imaged at sub-100 nm resolutions using scanning transmission ion microscopy (STIM), and that sub-cellular structural details can be identified. In addition to STIM imaging we have also demonstrated for the first time, that sub-cellular proton induced fluorescence imaging (on cultured N2A neuroblastoma cells ATCC) can also be carried out at resolutions of 200 nm, compared with 300-400 nm resolutions achieved by conventional optical fluorescence imaging. The combination of both techniques offers a potentially powerful tool in the quest for elucidating cell function, particularly when it should be possible in the near future to image down to sub-50 nm.

  10. MeV ion beam interaction with polymer films containing cross-linking agents

    International Nuclear Information System (INIS)

    Evelyn, A. L.

    1999-01-01

    Polymer films containing cross linking enhancers were irradiated with MeV alpha particles to determine the effects of MeV ion beam interaction on these materials. The contributed effects from the electronic and nuclear stopping powers were separated by irradiating stacked thin films of polyvinyl chloride (PVC), polystyrene (PS) and polyethersulfone (PES). This layered system allowed most of the effects of the electronic energy deposited to be experienced by the first layers and the last layers to receive most of the effects of the nuclear stopping power. RGA, Raman microprobe analysis, RBS and FTIR measured changes in the chemical structures of the irradiated films. The characterization resolved the effects of the stopping powers on the PVC, PS and PES and the results were compared with those from previously studied polymers that did not contain any cross linking agents

  11. A Monte Carlo simulation code for calculating damage and particle transport in solids: The case for electron-bombarded solids for electron energies up to 900 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang [College of Nuclear Science and Technology, Harbin Engineering University, Harbin 150001 (China); Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2017-03-15

    Current popular Monte Carlo simulation codes for simulating electron bombardment in solids focus primarily on electron trajectories, instead of electron-induced displacements. Here we report a Monte Carol simulation code, DEEPER (damage creation and particle transport in matter), developed for calculating 3-D distributions of displacements produced by electrons of incident energies up to 900 MeV. Electron elastic scattering is calculated by using full-Mott cross sections for high accuracy, and primary-knock-on-atoms (PKAs)-induced damage cascades are modeled using ZBL potential. We compare and show large differences in 3-D distributions of displacements and electrons in electron-irradiated Fe. The distributions of total displacements are similar to that of PKAs at low electron energies. But they are substantially different for higher energy electrons due to the shifting of PKA energy spectra towards higher energies. The study is important to evaluate electron-induced radiation damage, for the applications using high flux electron beams to intentionally introduce defects and using an electron analysis beam for microstructural characterization of nuclear materials.

  12. Energy loss of carbon transmitted 1-MeV H2+ ions

    International Nuclear Information System (INIS)

    Fritz, M.; Kimura, K.; Susuki, Y.; Mannami, M.

    1994-01-01

    Energy losses of 1-MeV H 2 + ions passing through carbon foils of 2-8 μg/cm 2 thickness have been measured and show besides the linear increase with target thickness a 0.4 keV offset. The stopping power derived from the observed energy losses is 1.15 times as large as the sum of the stopping powers for two single H + of the same velocity. Calculations of the stopping powers for H 2 + ions and diprotons, using first Born approximation, indicate that the H 2 + ions lose the binding electron upon entrance into the foil, traverse the target as diprotons and recapture target electrons at the exit surface, a scenario also supported by the 0.4 keV offset at zero thickness. (author)

  13. New source of MeV negative ion and neutral atom beams

    Energy Technology Data Exchange (ETDEWEB)

    Ter-Avetisyan, S., E-mail: sargis@gist.ac.kr [Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 500-712 (Korea, Republic of); Department of Physics and Photon Science, GIST, Gwangju 500-712 (Korea, Republic of); Braenzel, J.; Schnürer, M. [Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin 12489 (Germany); Prasad, R. [Institute for Laser and Plasma Physics, Heinrich Heine University, Duesseldorf 40225 (Germany); Borghesi, M. [School of Mathematics and Physics, The Queen’s University of Belfast, Belfast BT7-1NN (United Kingdom); Jequier, S.; Tikhonchuk, V. [Centre Lasers Intenses et Applications, CEA, CNRS, University of Bordeaux, 33405 Talence (France)

    2016-02-15

    The scenario of “electron-capture and -loss” was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities.

  14. New source of MeV negative ion and neutral atom beams

    International Nuclear Information System (INIS)

    Ter-Avetisyan, S.; Braenzel, J.; Schnürer, M.; Prasad, R.; Borghesi, M.; Jequier, S.; Tikhonchuk, V.

    2016-01-01

    The scenario of “electron-capture and -loss” was recently proposed for the formation of negative ion and neutral atom beams with MeV kinetic energies. However, it does not explain why the formation of negative ions in a liquid spray is much more efficient than with an isolated atom. The role of atomic excited states in the charge-exchange processes is considered, and it is shown that it cannot account for the observed phenomena. The processes are more complex than the single electron-capture and -loss approach. It is suggested that the shell effects in the electronic structure of the projectile ion and/or target atoms may influence the capture/loss probabilities

  15. Measurement and modelling of the radiation damage of silicon by MeV Ag ions

    International Nuclear Information System (INIS)

    Lindner, J.K.N.; Eder, J.; Stritzker, B.

    1999-01-01

    Depth profiles of the radiation damage produced by 4 MeV Ag ions in Si(111) at temperatures of 210--450 K are studied by optical reflectivity depth profiling and TEM for doses between 10 12 and 10 15 Ag/cm 2 . For high implantation temperatures, the depth of maximum damage is shown to be dose dependent. Point defect diffusion is shown to result in long tails of defect depth profiles. High-temperature amorphization is observed to proceed via the formation and bridge-like coalescence of isolated amorphous volumina. The damage at the depth of the maximum in the nuclear stopping power is described as a function of dose and temperature by the Hecking model. The model parameters and a comparison with those obtained for lighter ions reflect the particular properties of heavy ion collision cascades

  16. Enhanced photoelectrochemical properties of 100 MeV Si8+ ion irradiated barium titanate thin films

    International Nuclear Information System (INIS)

    Solanki, Anjana; Choudhary, Surbhi; Satsangi, Vibha R.; Shrivastav, Rohit; Dass, Sahab

    2013-01-01

    Highlights: ► Effect of 100 MeV Si 8+ ion irradiation on photoelectrochemical (PEC) properties of BaTiO 3 thin films was studied. ► Films were deposited on Indium doped Tin Oxide (ITO) coated glass by sol–gel spin coating technique. ► Optimal irradiation fluence for best PEC response was 5 × 10 11 ion cm −2 . ► Maximum photocurrent density was observed to be 0.7 mA cm −2 at 0.4 V/SCE. ► Enhanced photo-conversion efficiency was due to maximum negative flatband potential, donor density and lowest resistivity. -- Abstract: Effects of high electronic energy deposition on the structure, surface topography, optical property and photoelectrochemical behavior of barium titanate (BaTiO 3 ) thin films were investigated by irradiating films with 100 MeV Si 8+ ions at different ion fluences in the range of 1 × 10 11 –2 × 10 13 ions cm −2 . BaTiO 3 thin films were deposited on indium tin oxide coated glass substrate by sol gel spin coating method. Irradiation induced modifications in the films were analyzed using the results from XRD, SEM, cross sectional SEM, AFM and UV–Vis spectrometry. Maximum photocurrent density of 0.7 mA cm −2 at 0.4 V/SCE and applied bias hydrogen conversion efficiency (ABPE) of 0.73% was observed for BaTiO 3 film irradiated at 5 × 10 11 ions cm −2 , which can be attributed to maximum negative value of the flatband potential and donor density and lowest resistivity

  17. Distributions of neutron yields and doses around a water phantom bombarded with 290-MeV/nucleon and 430-MeV/nucleon carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, D., E-mail: satoh.daiki@jaea.go.jp [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kajimoto, T. [Hiroshima University, Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-8527 (Japan); Shigyo, N.; Itashiki, Y.; Imabayashi, Y. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Koba, Y.; Matsufuji, N. [National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba 263-8555 (Japan); Sanami, T. [High Energy Accelerator Research Organization, Oho-cho, Tsukuba-shi, Ibaraki 305-0801 (Japan); Nakao, N. [Shimizu Corporation, Etchujima, Koto-ku, Tokyo 135-8530 (Japan); Uozumi, Y. [Kyushu University, Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2016-11-15

    Double-differential neutron yields from a water phantom bombarded with 290-MeV/nucleon and 430-MeV/nucleon carbon ions were measured at emission angles of 15°, 30°, 45°, 60°, 75°, and 90°, and angular distributions of neutron yields and doses around the phantom were obtained. The experimental data were compared with results of the Monte-Carlo simulation code PHITS. The PHITS results showed good agreement with the measured data. On the basis of the PHITS simulation, we estimated the angular distributions of neutron yields and doses from 0° to 180° including thermal neutrons.

  18. Determining the stereochemical structures of molecular ions by ''Coulomb-explosion'' techniques with fast (MeV) molecular ion beams

    International Nuclear Information System (INIS)

    Gemmell, D.S.

    1980-01-01

    Recent studies on the dissociation of fast (MeV) molecular ion beams in thin foils suggest a novel alternative approach to the determination of molecular ion structures. In this article we review some recent high-resolution studies on the interactions of fast molecular ion beams with solid and gaseous targets and indicate how such studies may be applied to the problem of determining molecular ion structures. The main features of the Coulomb explosion of fast-moving molecular ion projectiles and the manner in which Coulomb-explosion techniques may be applied to the problem (difficult to attack by more conventional means) of determining the stereochemical structures of molecular ions has been described in this paper. Examples have been given of early experiments designed to elicit structure information. The techniques are still in their infancy, and it is to be expected that as both the technology and the analysis are refined, the method will make valuable contributions to the determination of molecular ion structures

  19. Anti-biofilm efficacy of 100 MeV gold ion irradiated polycarbonate against Salmonella typhi

    Science.gov (United States)

    Joshi, R. P.; Hareesh, K.; Bankar, A.; Sanjeev, G.; Asokan, K.; Kanjilal, D.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D.

    2017-12-01

    Polycarbonate (PC) films were irradiated by 100 MeV gold (Au7+) ions and characterized to study changes in its optical, chemical, surface morphology and thermal properties. UV-Visible spectroscopic results revealed the decrease in the optical band gap of PC after ion irradiation due to chain scission mainly at the carbonyl group which is corroborated by Fourier Transform Infrared spectroscopic results. X-ray diffractogram study showed decrease in crystallinity of PC film after irradiation. Scanning electron microscopic results showed the micropores formation in PC which results in surface roughening. Differential scanning calorimetric results revealed decrease in glass transition temperature indicating the decrease in molecular weight of PC corroborated by rheometric studies. PC films irradiated by 100 MeV Au7+ ions showed increased anti-biofilm activity against the human pathogen, Salmonella typhi (S. typhi). Morphology of S. typhi was changed due to stress of Au7+ irradiated PC. Cells length was increased with increasing fluences. The average cell length, cell volume and surface area was increased significantly (PBiofilm formation was inhibited ≈ 20% at lower fluence and 96% at higher fluence, which observed to be enhanced anti-biofilm activity in Au7+ irradiated PC.

  20. A gas ionisation Direct-STIM detector for MeV ion microscopy

    International Nuclear Information System (INIS)

    Norarat, Rattanaporn; Guibert, Edouard; Jeanneret, Patrick; Dellea, Mario; Jenni, Josef; Roux, Adrien; Stoppini, Luc; Whitlow, Harry J.

    2015-01-01

    Direct-Scanning Transmission Ion Microscopy (Direct-STIM) is a powerful technique that yields structural information in sub-cellular whole cell imaging. Usually, a Si p-i-n diode is used in Direct-STIM measurements as a detector. In order to overcome the detrimental effects of radiation damage which appears as a broadening in the energy resolution, we have developed a gas ionisation detector for use with a focused ion beam. The design is based on the ETH Frisch grid-less off-axis Geiger–Müller geometry. It is developed for use in a MeV ion microscope with a standard Oxford Microbeams triplet lens and scanning system. The design has a large available solid angle for other detectors (e.g. proton induced fluorescence). Here we report the performance for imaging ReNcells VM with μm resolution where energy resolutions of <24 keV fwhm could be achieved for 1 MeV protons using isobutane gas

  1. Applications of focused MeV light ion beams for high resolution channeling contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, D N; Breese, M B.H.; Prawer, S; Dooley, S P; Allen, M G; Bettiol, A A; Saint, A [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Ryan, C G [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1994-12-31

    The technique of Nuclear Microscopy, utilizing a focused ion probe of typically MeV H{sup +} or He{sup +} ions, can produce images where the contrast depends on typical Ion Beam Analysis (lBA) processes. The probe forming lens system usually utilizes strong focusing, precision magnetic quadrupole lenses and the probe is scanned over the target to produce images. Originally, this imaging technique was developed to utilize backscattered particles with incident beam currents typically of a few nA, and the technique became known as Channeling Contrast Microscopy (CCM). Recently, the technique has been developed further to utilize the forward scattering of ions incident along a major crystal axis in thin crystals. This technique is known as Channeling Scanning Transmission Ion Microscopy (CSTIM). Since nearly all incident ions are detected, CSTIM is highly efficient and very low beam currents are sufficient for imaging, typically as low as a few fA. This allows probes as small as 50 nm to be used. In this paper we briefly review the recent applications of these emerging techniques to a variety of single crystal materials (authors). 13 refs., 5 figs.

  2. Applications of focused MeV light ion beams for high resolution channeling contrast imaging

    Energy Technology Data Exchange (ETDEWEB)

    Jamieson, D.N.; Breese, M.B.H.; Prawer, S.; Dooley, S.P.; Allen, M.G.; Bettiol, A.A.; Saint, A. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Ryan, C.G. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1993-12-31

    The technique of Nuclear Microscopy, utilizing a focused ion probe of typically MeV H{sup +} or He{sup +} ions, can produce images where the contrast depends on typical Ion Beam Analysis (lBA) processes. The probe forming lens system usually utilizes strong focusing, precision magnetic quadrupole lenses and the probe is scanned over the target to produce images. Originally, this imaging technique was developed to utilize backscattered particles with incident beam currents typically of a few nA, and the technique became known as Channeling Contrast Microscopy (CCM). Recently, the technique has been developed further to utilize the forward scattering of ions incident along a major crystal axis in thin crystals. This technique is known as Channeling Scanning Transmission Ion Microscopy (CSTIM). Since nearly all incident ions are detected, CSTIM is highly efficient and very low beam currents are sufficient for imaging, typically as low as a few fA. This allows probes as small as 50 nm to be used. In this paper we briefly review the recent applications of these emerging techniques to a variety of single crystal materials (authors). 13 refs., 5 figs.

  3. The real potential continuous ambiguity for 90 MeV Li ions

    International Nuclear Information System (INIS)

    Cook, J.; Barnwell, J.M.; Clarke, N.M.; Griffiths, R.J.

    1980-01-01

    The features of discrete and continuous ambiguities in the real phenomenological optical potential are clarified. The continuous ambiguity in the real potential for the scattering of 90 MeV 6 Li and 7 Li ions from 27 Al is investigated. For 6 Li the ambiguity is of Igo (Phys. Rev. Lett.; 1: 72 (1958) and Phys. Rev.; 115: 1665 (1959)) type but for 7 Li it is of Vrsup(n) = constant type. The implications of this are that 7 Li is less strongly absorbed than 6 Li. (author)

  4. Backscattering/transmission of 2 MeV He{sup ++} ions quantitative correlation study

    Energy Technology Data Exchange (ETDEWEB)

    Berec, V., E-mail: bervesn@gmail.com [Institute of Nuclear Sciences Vinca, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Germogli, G.; Mazzolari, A.; Guidi, V. [INFN Sezione di Ferrara and Dipartimento di Fisica e Scienze della Terra, Via Saragat 1, 44100 Ferrara (Italy); De Salvador, D. [Dipartimento di Fisica, Università di Padova, Via Marzolo n.8, 35131 Padova (Italy); INFN Laboratori Nazionali di Legnaro, Viale Università 2, 35020 Legnaro, PD (Italy); Bacci, L. [INFN Laboratori Nazionali di Legnaro, Viale Università 2, 35020 Legnaro, PD (Italy)

    2015-07-15

    In this work we report on detailed findings of planar channeling oscillations of 2 MeV He{sup ++} particles in (1 1 0) silicon crystal. The exact correlation and coherence mechanism between confined particles oscillating trajectories are analyzed theoretically and experimentally in backscattering/transmission geometry. Regular patterns of channeled He{sup ++} ion planar oscillations are shown to be dominated by the crystal harmonic-oscillator potential and multiple scattering effect. For the first time it was shown that under the planar channeling conditions trajectories of positively charged particles exhibit observable correlation dynamics, including the interference effect. Quantitative estimation of channeling efficiency is performed using path integral method.

  5. Diffusion of alpha-like MeV ions in TFTR

    International Nuclear Information System (INIS)

    Boivin, R.L.; Zweben, S.J.; Chang, C.S.; Hammett, G.; Mynick, H.E.; White, R.B.

    1991-01-01

    Single particle confinement of alpha particles is of crucial importance in reactor-grade tokamaks like BPX and ITER. Besides the well-known process of first-orbit losses, mechanisms that could lead to significant loss of alpha particles are turbulence-induced diffusion and toroidal field ripple stochastic diffusion. These two mechanisms have been separately studied in TFTR using two different detectors (one at the bottom of the machine and the other near the outer midplane) which can detect escaping charged fusion products, namely the 1 MeV triton and the 3 MeV proton in D-D plasmas (and also the 3.5 MeV alpha in D-T). The main difficulty in this type of experiment lies in the necessity of distinguishing the diffusion process from the always-present first-orbit loss-process. In this paper, we show how these two processes can be distinguished using the pitch-angle discrimination of the detectors. The pitch-angle is defined here as the angle of the particle trajectory with respect to the toroidal direction and so is a measure of the ion magnetic moment, μ. Results obtained at the midplane would be the first reported evidence of TF ripple diffusion in a tokamak. (author) 3 refs., 2 figs

  6. Design study of prototype accelerator and MeV test facility for demonstration of 1 MeV, 1 A negative ion beam production

    International Nuclear Information System (INIS)

    Inoue, Takashi; Hanada, Masaya; Miyamoto, Kenji; Ohara, Yoshihiro; Okumura, Yoshikazu; Watanabe, Kazuhiro; Maeno, Shuichi.

    1994-08-01

    In fusion reactors such as ITER, a neutral beam injector of MeV class beam energy and several tens MW class power is required as one of candidates of heating and current drive systems. However, the beam energy of existing high power accelerators are one order of magnitude lower than the required value. In order to realize a neutral beam injector for the fusion reactor, 'Proof-of-Principle' of such high energy acceleration is a critical issue at a reactor relevant beam current and pulse length. An accelerator and an accelerator facility which are necessary to demonstrate the Proof-of-Principle acceleration of negative ion beams up to 1 MeV, have been designed in the present study. The accelerator is composed of a cesium-volume type ion source and a multi-stage electrostatic acceleration system [Prototype Accelerator]. A negative hydrogen ion beam with the current of about one ampere (1 A) can be accelerated up to 1 MeV at a low operating pressure. Two types of acceleration system, a multi-multi type and a multi-single type, have been studied. The test facility has sufficient capability for the test of the Prototype Accelerator [MeV Test Facility]. The dc high voltage generator for negative ion acceleration is a Cockcroft-Walton type and capable of delivering 1 A at 1 MV (=1 MW) for 60 s. High voltage components including Prototype Accelerator are installed in a SF 6 vessel pressurized at 6 kg/cm 2 to overcome high voltage gradients. The vessel and the beamline are installed in a X-ray shield. (author)

  7. 100 MeV silver ions induced defects and modifications in silica glass

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, Vijay S.; Deore, Avinash V.; Dahiwale, S.S. [Department of Physics, University of Pune, Pune 411007 (India); Kanjilal, D. [Inter University Accelerator Centre, New Delhi 110067 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D., E-mail: sanjay@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India)

    2014-07-15

    Highlights: •Study of silver ion induced defects and modifications in silica glass. •Variation in oxygen deficiency centres (ODA-II) and nonbridging oxygen hole centres (NBOHC). •Study of structural damage in terms of Urbach energy. -- Abstract: A few silica glass samples having 1 cm{sup 2} area and 0.1 cm thickness were irradiated with 100 MeV energy Ag{sup 7+} ions for the fluences ranging from 1 × 10{sup 12} ions/cm{sup 2} to 5 × 10{sup 13} ions/cm{sup 2}. The optical properties and the corresponding induced defects were characterised by the techniques such as UV–Visible, Photoluminescence (PL), Fourier transform infrared (FTIR), and Electron spin resonance (ESR) spectroscopy. The UV–Visible absorption spectra show two peaks, one at 5 eV and another weak peak at 5.8 eV. A peak observed at 5.0 eV corresponds to B{sub 2} band (oxygen deficiency in SiO{sub 2} network) and the peak at 5.8 eV is due to the paramagnetic defects like E′ centre. The intensities of these peaks found to be increased with increase in ion fluence. It attributes to the increase in the concentration of E′ centres and B{sub 2} band respectively. In addition, the optical band gap energy, Urbach energy and the defects concentration have been calculated using Urbach plot. The optical band gap found to be decreased from 4.65 eV to 4.39 eV and the Urbach energy found to be increased from 60 meV to 162 meV. The defect concentration of nonbridging oxygen hole centres (NBOHC) and E′ centres are found to be increased to 1.69 × 10{sup 13} cm{sup −3} and 3.134 × 10{sup 14} cm{sup −3} respectively. In PL spectra, the peak appeared at 1.92 eV and 2.7 eV envisage the defects of nonbridging oxygen hole centres and B{sub 2α} oxygen deficient centres respectively. ESR spectra also confirms the existence of E′ and NBOHC centres. FTIR spectra shows scissioning of Si-O-Si bonds and the formation of Si-H and Si-OH bonds, which supports to the co-existence of the defects induced by Ag

  8. Structural disorder in sapphire induced by 90.3 MeV xenon ions

    International Nuclear Information System (INIS)

    Kabir, A.; Meftah, A.; Stoquert, J.P.; Toulemonde, M.; Monnet, I.; Izerrouken, M.

    2010-01-01

    In our previous work , we have evidenced, using RBS-C, two effects in the aluminium sublattice of sapphire irradiated with 90.3 MeV xenon ions: a partial disorder creation that saturates at ∼40% followed above a threshold fluence by a highly disordered layer appearing behind the surface. In this work, by RBS-C analysis of the oxygen sublattice, we have observed only one regime of partial disorder creation that saturates at ∼60% in tracks of cross-section double of that found for the aluminium sublattice. Complementary analysis by X-ray diffraction shows that the lattice strain increases with the fluence until a maximum is reached about 7.5 x 10 12 ions/cm 2 . For higher fluences, strain decreases first indicating a little stress relaxation in the material and tends afterwards, to remain constant. This stress relaxation is found to be related to the aluminium sublattice high disorder.

  9. Effects of high energy (MeV) ion beam irradiation on polyethylene terephthalate

    International Nuclear Information System (INIS)

    Singh, Nandlal; Sharma, Anita; Avasthi, D.K.

    2003-01-01

    Irradiation effects of 50 MeV Li 3+ ion beams in polyethylene terephthalate (PET) films were studied with respect to their structural and electrical properties by using Fourier transform infrared (FTIR) spectroscopy and ac electrical measurement in the frequency range: 50-100 kHz at different temperatures of 30-150 deg. C. It is found that ac resistivity of PET decreases as frequency increases. The temperature dependencies of dielectric loss tangent exhibit a peak (T g ) at 60 deg. C. The capacitance value of irradiated PET is almost temperature independent and ones increases with an increasing of lithium fluence. FTIR spectra show various bands related to C-H, C-O, C-O-C molecular bonds and groups which get modified or break down due to ion beam irradiation

  10. RBS cross-section of MeV ions channeling in crystals from quantum theory

    International Nuclear Information System (INIS)

    Den Besten, J.L.; Jamieson, D.N.; Spizzirri, P.G.; Allen, L.J.

    1999-01-01

    We present an alternative approach to describing Rutherford Backscattered (RBS) angular yield scans. The Bloch wave method to formulate the cross-section is a fundamental approach originating from Schrodinger's equation. This quantum formulation is often used when describing various aspects of electron diffraction including Backscattering, EDX and TEM but has seen little application to the very short wavelength regime of MeV ions. It offers several significant advantages. Great freedom is given to crystal properties and structure in the theory allowing a fundamental insight into the channeling phenomena and hence the crystal itself. We have calculated both planar and axial channeling scans and these maps are shown to be in good agreement to their experimental counterparts. There is excellent correlation between the theoretical and experimental results for both χ min and Ψ 1/2 . Further investigation is required into the area of absorption or dechanneling. This phenomenon requires different mechanisms for electron and ion scattering differ greatly

  11. Structure Characterization of Modified Polyimide Films Irradiated by 2 MeV Si Ions

    International Nuclear Information System (INIS)

    Tian-Xiang, Chen; Shu-De, Yao; Kun, Wang; Huan, Wang; Zhi-Bo, Ding; Di, Chen

    2009-01-01

    Structures of polyimide (6051) films modified by irradiation of 2.0 MeV Si ions with different fluences are studied in detail. Variations of the functional groups in polyimide are investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. The results indicate that the functional groups can be destroyed gradually with the increasing ion fluence. The variations of structure and element contents are characterized by x-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy (XPS). The results indicate that the contents of N and O decrease significantly compared with the original samples, some graphite-like and carbon-rich phases are formed in the process of irradiation

  12. 75 MeV boron ion irradiation studies on Si PIN photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakara Rao, Y.P.; Praveen, K.C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India); Rejeena Rani, Y. [Integrated Circuits Division, Bharat Electronics Limited, Bangalore 560013, Karnataka (India); Tripathi, Ambuj [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Gnana Prakash, A.P., E-mail: gnanap@hotmail.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570006 (India)

    2013-12-01

    The highly sensitive silicon PIN photodiodes were fabricated to use in radiation environments. The Si PIN photodiodes are coated with 150 nm silicon dioxide (SiO{sub 2}) as anti-reflective (AR) coating. The presence of AR coating on the performance of irradiated PIN photodiodes is studied up to a total dose of 10 Mrad. The effects of 75 MeV boron (B{sup 5+}) ions and {sup 60}Co gamma radiation on the I–V, C–V and spectral responses of PIN photodiodes were studied systematically to understand the radiation tolerance of the devices. The 75 MeV B{sup 5+} irradiation results are compared with {sup 60}Co gamma irradiated results in the same dose range for 1 mm × 1 mm and 10 mm × 10 mm active area PIN photodiodes. The irradiation results show that the ion irradiated PIN photodiodes show more degradation when compared {sup 60}Co gamma irradiated devices. The irradiation results are presented in this paper and the possible mechanism behind the degradation of photodiodes is also discussed in the paper.

  13. Nanoconstructive bombardment

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J [VSW Ion Beam Systems, Warrington (UK)

    1990-06-01

    Ion beams with energies as low as a few eV can be used, in the very clean environment of an ultra-high vacuum system, to achieve the fine control for atomic-scale experiments. They are becoming widely used in nanotechnology. Recent advances in beam quality, overcoming the mutual repulsion of the ions, have meant that mass-analysed low energy ion beams have been developed around the world for a variety of applications in material science, and physics. The structure of such devices is outlined and possible future applications noted. (U.K.).

  14. Formation mechanism and yield of molecules ejected from ZnS, CdS, and FeS2 during ion bombardment

    International Nuclear Information System (INIS)

    Nikzad, S.; Calaway, W.F.; Pellin, M.J.; Young, C.E.; Gruen, D.M.; Tombrello, T.A.

    1994-01-01

    Neutral species ejected from single crystals of ZnS, CdS, and FeS 2 during ion bombardment by 3 keV Ar + were detected by laser post-ionization followed by time-of-flight mass spectrometry. While metal atoms (Fe, Zn, Cd) and S 2 were the dominant species observed, substantial amounts of S, FeS, Zn 2 , ZnS, Cd 2 , and CdS were also detected. The experimental results demonstrate that molecules represent a larger fraction of the sputtered yield than was previously believed from secondary ion mass spectrometry experiments. In addition, the data suggest that the molecules are not necessarily formed from adjacent atoms in the solid and that a modified form of the recombination model could provide a mechanism for their formation

  15. High energy (MeV) ion-irradiated π-conjugated polyaniline: Transition from insulating state to carbonized conducting state

    International Nuclear Information System (INIS)

    Park, S.K.; Lee, S.Y.; Lee, C.S.; Kim, H.M.; Joo, J.; Beag, Y.W.; Koh, S.K.

    2004-01-01

    High energy (MeV) C 2+ , F 2+ , and Cl 2+ ions were irradiated onto π-conjugated polyaniline emeraldine base (PAN-EB) samples. The energy of an ion beam was controlled to a range of 3-4.5 MeV, with the ion dosage varying from 1x10 12 to 1x10 16 ions/cm 2 . The highest dc conductivity (σ dc ) at room temperature was measured to be ∼60 S/cm for 4.5 MeV Cl 2+ ion-irradiated PAN-EB samples with a dose of 1x10 16 ions/cm 2 . We observed the transition of high energy ion-irradiated PAN-EB samples from insulating state to conducting state as a function of ion dosage based on σ dc and its temperature dependence. The characteristic peaks of the Raman spectrum of the PAN-EB samples were reduced, while the D-peak (disordered peak) and the G peak (graphitic peak) appeared as the ion dose increased. From the analysis of the D and G peaks of the Raman spectra of the systems compared to multiwalled carbon nanotubes, ion-irradiated graphites, and annealed carbon films, the number of the clusters of hexagon rings with conducting sp 2 -bonded carbons increased with ion dosage. We also observed the increase in the size of the nanocrystalline graphitic domain of the systems with increasing ion dosage. The intensity of normalized electron paramagnelic resonance signal also increased in correlation with ion dose. The results of this study demonstrate that π-conjugated pristine PAN-EB systems changed from insulating state to carbonized conducting state through high energy ion irradiation with high ion dosage

  16. Experimental and Calculated Effectiveness of a Radiochromic Dye Film to Stopping 21 MeV 7Li- and 64 MeV 16O Ions

    DEFF Research Database (Denmark)

    Olsen, Kjeld J; Hansen, Johnny

    1984-01-01

    Relative radiation effectiveness, RE, of 21 MeV 7Li and 64 MeV 16O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a δ-ray theory for heavy charged...... particles developed by Katz et al. The experiment was designed to test calculations particularly in the Bragg-peak region of the slowing down particles where significant deviation between theory and experiment was found. Fitting of the characteristic D37 dose and the size of the radiation sensitive element...... in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the δ-ray spectrum...

  17. Heavy-ion induced desorption of a TiZrV coated vacuum chamber bombarded with 5 MeV/u Ar8+ beam at grazing incidence

    International Nuclear Information System (INIS)

    Hedlund, E.; Malyshev, O. B.; Westerberg, L.; Krasnov, A.; Semenov, A. S.; Leandersson, M.; Zajec, B.; Kollmus, H.; Bellachioma, M. C.; Bender, M.; Kraemer, A.; Reich-Sprenger, H.

    2009-01-01

    TiZrV nonevaporable getter (NEG) coated vacuum chambers is a new vacuum technology which is already used in many particle accelerators worldwide. This coating is also of interest for heavy-ion accelerator vacuum chambers. Heavy-ion desorption yields from an activated as well as a CO saturated NEG coated tube have been measured with 5 MeV/u Ar 8+ beam. The sticking probability of the NEG film was obtained by using the partial pressure ratios on two sides of the NEG coated tube. These ratios were compared to results of modeling of the experimental setup with test particle Monte Carlo and angular coefficient methods. The partial pressures inside the saturated NEG coated tube bombarded with heavy ions were up to 20 times larger than those inside the activated one. However, the partial pressure of methane remained the same. The value of the total desorption yield from the activated NEG coated tube is 2600 molecules/ion. The desorption yields after saturation for CH 4 , H 2 , and CO 2 were found to be very close to the yields measured after the activation, while CO increased by up to a factor of 5. The total desorption yield for the saturated tube is up to 7000 molecules/ion. The large value of the desorption yield of the activated NEG coated tube, an order of magnitude higher than the desorption yield from a stainless steel tube at normal incident angle, could be explained by the grazing incident angle

  18. Calibration of BAS-TR image plate response to high energy (3-300 MeV) carbon ions

    Science.gov (United States)

    Doria, D.; Kar, S.; Ahmed, H.; Alejo, A.; Fernandez, J.; Cerchez, M.; Gray, R. J.; Hanton, F.; MacLellan, D. A.; McKenna, P.; Najmudin, Z.; Neely, D.; Romagnani, L.; Ruiz, J. A.; Sarri, G.; Scullion, C.; Streeter, M.; Swantusch, M.; Willi, O.; Zepf, M.; Borghesi, M.

    2015-12-01

    The paper presents the calibration of Fuji BAS-TR image plate (IP) response to high energy carbon ions of different charge states by employing an intense laser-driven ion source, which allowed access to carbon energies up to 270 MeV. The calibration method consists of employing a Thomson parabola spectrometer to separate and spectrally resolve different ion species, and a slotted CR-39 solid state detector overlayed onto an image plate for an absolute calibration of the IP signal. An empirical response function was obtained which can be reasonably extrapolated to higher ion energies. The experimental data also show that the IP response is independent of ion charge states.

  19. Diagnosis by proton bombardment

    International Nuclear Information System (INIS)

    Steward, V.W.; Koehler, A.M.

    1976-01-01

    Beams of monoenergetic protons or other charged ions are passed through the living human body to detect abnormalities and obstructions in body tissue, which abnormalities and obstructions are visualized as density variations in the particle image emerging from the body part under investigation. The particles used are preferably protons having an energy of 100 to 300 MeV, more especially 200 to 300 MeV. The method is of use in detecting inter alia tumors, blood clots, infarcts, soft tissue lesions and multiple sclerosis in patients without exposure to high radiation dosages. 6 claims, 2 drawing figures

  20. Experimental studies of the break-up of 156 MeV 6Li-ions at extreme forward angles using the Karlsruhe magnetic spectrograph 'Little John'

    International Nuclear Information System (INIS)

    Jelitto, H.

    1987-05-01

    6 Li-induced break-up reactions have been investigated at reaction angles in extreme forward direction including O 0 with the Karlsruhe Magnetic Spectrograph 'Little John'. The experiments were characterized by the minimization of the high experimental background that dominates at small emission angles. Inclusive alpha-particle and deuteron spectra from the bombardement of 12 C- and 208 Pb-targets with 156 MeV 6 Li-ions have been measured. Below the grazing angle the Coulomb interaction shows a distinct influence on the angular distributions of the fragments. A simple spectator-model and a more realistic description within the DWBA-formalism largely allows a reproduction of the data. In the light of the reverse reaction α + d → 6 Li + γ at small α-d-relative energies, which is of considerable interest for astrophysics, a particle-particle-coincidence measurement with θ α = 5 0 and θ d = -2 0 has been performed. The result could be reproduced reasonably well by a simple Monte-Carlo-simulation. Beside the treatment of a physical problem this work deals with the start-up of the magnetic spectrograph and the clarification of spectrograph specific questions concerning the data reduction. (orig.) [de

  1. Stopping power of liquid water for carbon ions in the energy range between 1 MeV and 6 MeV

    International Nuclear Information System (INIS)

    Rahm, J M; Baek, W Y; Rabus, H; Hofsäss, H

    2014-01-01

    The stopping power of liquid water was measured for the first time for carbon ions in the energy range between 1 and 6 MeV using the inverted Doppler shift attenuation method. The feasibility study carried out within the scope of the present work shows that this method is well suited for the quantification of the controversial condensed phased effect in the stopping power for heavy ions in the intermediate energy range. The preliminary results of this work indicate that the stopping power of water for carbon ions with energies prevailing in the Bragg-peak region is significantly lower than that of water vapor. In view of the relatively high uncertainty of the present results, a new experiment with uncertainties less than the predicted difference between the stopping powers of both water phases is planned. (paper)

  2. High repetition rate laser-driven MeV ion acceleration at variable background pressures

    Science.gov (United States)

    Snyder, Joseph; Ngirmang, Gregory; Orban, Chris; Feister, Scott; Morrison, John; Frische, Kyle; Chowdhury, Enam; Roquemore, W. M.

    2017-10-01

    Ultra-intense laser-plasma interactions (LPI) can produce highly energetic photons, electrons, and ions with numerous potential real-world applications. Many of these applications will require repeatable, high repetition targets that are suitable for LPI experiments. Liquid targets can meet many of these needs, but they typically require higher chamber pressure than is used for many low repetition rate experiments. The effect of background pressure on the LPI has not been thoroughly studied. With this in mind, the Extreme Light group at the Air Force Research Lab has carried out MeV ion and electron acceleration experiments at kHz repetition rate with background pressures ranging from 30 mTorr to >1 Torr using a submicron ethylene glycol liquid sheet target. We present these results and provide two-dimensional particle-in-cell simulation results that offer insight on the thresholds for the efficient acceleration of electrons and ions. This research is supported by the Air Force Office of Scientific Research under LRIR Project 17RQCOR504 under the management of Dr. Riq Parra and Dr. Jean-Luc Cambier. Support was also provided by the DOD HPCMP Internship Program.

  3. 100 MeV Ag{sup 7+} ion induced physicochemical changes in isotactic polypropylene

    Energy Technology Data Exchange (ETDEWEB)

    Mathakari, N.L. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Kanjilal, D. [Inter University Accelerator Center, New Delhi (India); Bhoraskar, V.N. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India); Dhole, S.D. [Microtron Accelerator Laboratory, Department of Physics, University of Pune, Ganeshkhind, Pune 411007, Maharashtra (India)], E-mail: sanjay@physics.unipune.ernet.in

    2008-04-15

    Thin films of isotactic polypropylene having 500 {mu}m thickness were irradiated with 100 MeV Ag{sup 7+} ions at the fluences varying from 10{sup 11} to 5 x 10{sup 12} ions/cm{sup 2}. The properties such as chemical, optical, structural and surface morphology were characterized by techniques namely FTIR, UV-visible, photoluminescence, XRD, SEM and contact angle method. The FTIR spectra show the scissioning of C-H and C-C bonds, whereas, in photoluminescence, the intensities of the peaks at 440 and 480 nm in emission spectra and at 236 nm in excitation spectra observed to be decreased with increase in ion fluence. This may be due to the decomposition of luminescent centers. The UV-visible spectra also show a remarkable red shift from 218 to 367 nm and the subsequent large reduction in the optical band gap from 5.37 to 3.39 eV. This attributes to the carbonization or graphitization of polypropylene. On the contrary, the intensities of XRD peaks, particularly the peak due to 1 1 0 planes, shows sufficient enhancement which signifies overall increase in crystallinity. This ascribes to relief in the local strain on the crystallites due to scissioning of tie molecules in the amorphous zones. The contact angle has increased from 78 deg. to 97 deg. which reveals the absence of hydrophilic functional groups, carbonization and surface roughening. The result is also supported by SEM analysis.

  4. Depth distribution of carrier lifetime in 65 MeV oxygen ion irradiated silicon wafers

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, N.S. [Ecotopia Science Institute, Division of Energy Science, Nagoya University, Nagoya (Japan); Dahiwale, S.S. [Department of Physics, University of Pune, Pune 411 007 (India); Kanjilal, D. [Nuclear Science Centre, New Delhi (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411 007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411 007 (India)]. E-mail: sanjay@physics.unipune.ernet.in

    2006-03-15

    CZ-grown, n-doped crystalline Si(1 1 1) of resistivity 60 {omega} cm and 140 {omega} cm were irradiated with 65 MeV energy oxygen ions, in the fluence range of 2 x 10{sup 1}-10{sup 14} ions/cm{sup 2}. The depth and spatial profile of excess minority carrier recombination time {tau} (lifetime) was measured using photoconductive decay (PCD) method. Lifetime measurements were carried out before the stopping range of impinging ions. Results show a monotonous decrease in lifetime with fluence, which is attributed to defect creation mechanism by electronic energy loss based on the thermal spike model. Also, surface modification is expected with a small loss in crystalline quality. This surface is considered to be a multi-crystalline surface with large grain boundaries that act as trapping sites for excess holes in n-Si(1 1 1). Annealing of the irradiated samples showed a near complete recovery at 750 deg. C for a period of 1 h.

  5. Investigations on 40 MeV Li3+ ions irradiated GaN epilayers

    International Nuclear Information System (INIS)

    Suresh Kumar, V.; Kumar, J.; Kanjilal, D.; Asokan, K.; Mohanty, T.; Tripathi, A.; Rossi, Francisca; Zappettini, A.; Lazzarani, L.; Ferrari, C.

    2008-01-01

    The Metal Organic Chemical Vapour Deposition (MOCVD) grown n-type Gallium nitride (GaN) layers on sapphire (0 0 0 1) substrates have been irradiated at low and room temperatures with 40 MeV Li 3+ ions at the fluence of 1 x 10 13 ions cm -2 . Irradiated samples were characterised by using X-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy and atomic force microscopy (AFM). XRD results show that the formation of Ga 2 O 3 has been observed upon irradiation. This is due to interface mixing of GaN/Al 2 O 3 , at both temperatures. Also the GaN (0 0 0 2) peak splits into two at low temperature irradiation. PL measurements show a yellow emission band shift towards blue band side upon irradiation at 77 K. Raman studies indicate that the lattice disorder is high at room temperature irradiation compared to low temperature irradiation. AFM images indicate the increasing surface roughness after ion irradiation at room temperature when compared to pristine GaN and low temperature irradiated GaN. These observations are discussed in detail with the use of complementary techniques

  6. Magnetic properties of a stainless steel irradiated with 6 MeV Xe ions

    Science.gov (United States)

    Xu, Chaoliang; Liu, Xiangbing; Qian, Wangjie; Li, Yuanfei

    2017-11-01

    Specimens of austenitic stainless steel were irradiated with 6 MeV Xe ions at room temperature to 2, 7, 15 and 25 dpa. The vibrating sample magnetometer (VSM), grazing incidence X-ray diffraction (GIXRD) and positron annihilation lifetime spectroscopy (PLS) were carried out to analysis the magnetic properties and microstructural variations. The magnetic hysteresis loops indicated that higher irradiation damage causes more significant magnetization phenomenon. The equivalent saturated magnetization Mes and coercive force Hc were obtained from magnetic hysteresis loops. It is indicated that the Mes increases with irradiation damage. While Hc increases first to 2 dpa and then decreases continuously with irradiation damage. The different contributions of irradiation defects and ferrite precipitates on Mes and Hc can explain these phenomena.

  7. Restoration of an electrical breakdown Terahertz emitter by 2 MeV He+ ion implantation

    International Nuclear Information System (INIS)

    Yang kang; Ma Mingwang; Chen Xiliang; Zhu Zhiyong

    2009-01-01

    The irradiation of solids by energetic particles may cause extensive displacement cascades and point defects (vacancies and interstitials), and can be widely used for material modification. In order to repair an electrical breakdown photoconductive antenna (PCA), we irradiated the (100)-oriented, low-temperature (LT) grown GaAs substrate with 10 16 /cm 2 of 2 MeV helium ions. After being implanted, electric resistance of the PCA has increased from 800 Ω to 60 ΜΩ. The irradiated PCA exhibits improvements in the output power in comparison with the electrical breakdown PCA and its signal intensity has increased from 2 nA to 8 nA. Accordingly, its output power has become more than one order of magnitude higher than that before irradiation. The frequency range of PCA has obviously improvement. (authors)

  8. Fragment ion distribution in charge-changing collisions of 2-MeV Si ions with C60

    Science.gov (United States)

    Itoh, A.; Tsuchida, H.; Miyabe, K.; Majima, T.; Nakai, Y.

    2001-09-01

    We have measured positive fragment ions produced in collisions of 2 MeV Siq+ (q=0, 1, 2, 4) projectiles with a C60 molecular target. The measurement was performed with a time-of-flight coincidence method between fragment ions and charge-selected outgoing projectiles. For all the charge-changing collisions investigated here, the mass distribution of small fragment ions C+n (n=1-12) can be approximated fairly well by a power-law form of n-λ as a function of the cluster size n. The power λ derived from each mass distribution is found to change strongly according to different charge-changing collisions. As a remarkable experimental finding, the values of λ(loss) in electron loss collisions are almost the same for the same final charge states k irrespective of the initial charge q, exhibiting a nearly perfect linear relationship with k. We also performed calculations of the projectile ionization on the basis of the semiclassical approximation and obtained inelastic energy deposition for individual collision processes. The estimated energy deposition is found to have a simple correlation with the experimentally determined values of λ(loss).

  9. Si(LMM) Auger electron emission from Si alloys by keV Ar/sup +/ ion bombardment, new effect and application

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, A; Kim, S; Imura, T; Iwami, M [Osaka Univ., Suita (Japan). Faculty of Engineering

    1979-09-01

    Si(LMM) Auger spectra excited by keV ion bombardment were studied in Si alloyed with several elements (Au, Cu, Pd, Ni, C, and H). The spectra differed completely from those of pure Si. The main characteristics are (1) the spectra are composed of two well-separated peaks (88 and 92 eV) called the atomic-like peak (88 eV) and the bulk-like peak (92 eV); and (2) the atomic-like peak is enhanced with respect to the bulk-like peak, and this enhancement becomes more obvious as the concentration of partner elements of the alloys are increased. The possible application of the present phenomena is proposed as a technique for detecting the homogeneity of Si alloy films in the three-dimensional sense - as an example, the three-dimensional distribution of hydrogen in hydrogenated amorphous silicon (a-Si-H).

  10. Suppression of self-organized surface nanopatterning on GaSb/InAs multilayers induced by low energy oxygen ion bombardment by using simultaneously sample rotation and oxygen flooding

    Science.gov (United States)

    Beainy, Georges; Cerba, Tiphaine; Bassani, Franck; Martin, Mickaël; Baron, Thierry; Barnes, Jean-Paul

    2018-05-01

    Time of flight secondary ion mass spectrometry (ToF-SIMS) is a well-adapted analytical method for the chemical characterization of concentration profiles in layered or multilayered materials. However, under ion beam bombardment, initially smooth material surface becomes morphologically unstable. This leads to abnormal secondary ion yields and depth profile distortions. In this contribution, we explore the surface topography and roughening evolution induced by O2+ ion bombardment on GaSb/InAs multilayers. We demonstrate the formation of nanodots and ripples patterning according to the ion beam energy. Since the latter are undesirable for ToF-SIMS analysis, we managed to totally stop their growth by using simultaneously sample rotation and oxygen flooding. This unprecedented coupling between these two latter mechanisms leads to a significant enhancement in depth profiles resolution.

  11. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vidovic, Z

    1997-06-15

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  12. Secondary electron emission of thin carbon foils under the impact of hydrogen atoms, ions and molecular ions, under energies within the MeV range; Multiplicite des electrons secondaires emis par des cibles minces de carbone sous l'impact de projectiles H0, H2+, H3+ d'energie de l'ordre du MeV

    Energy Technology Data Exchange (ETDEWEB)

    Vidovic, Z

    1997-06-15

    This work focuses on the study of the emission statistics of secondary electrons from thin carbon foils bombarded with H{sup 0}, H{sub 2}{sup +} and H{sub 3}{sup +} projectiles in the 0.25-2.2 MeV energy range. The phenomenon of secondary electron emission from solids under the impact of swift ions is mainly due to inelastic interactions with target electrons. The phenomenological and theoretical descriptions, as well as a summary of the main theoretical models are the subject of the first chapter. The experimental set-up used to measure event by event the electron emission of the two faces of a thin carbon foil traversed by an energetic projectile is described in the chapter two. In this chapter are also presented the method and algorithms used to process experimental spectra in order to obtain the statistical distribution of the emitted electrons. Chapter three presents the measurements of secondary electron emission induced by H atoms passing through thin carbon foils. The secondary electron yields are studied in correlation with the emergent projectile charge state. We show the peculiar role of the projectile electron, whether it remains or not bound to the incident proton. The fourth chapter is dedicated to the secondary electron emission induced by H{sub 2}{sup +} and H{sub 3}{sup +} polyatomic ions. The results are interpreted in terms of collective effects in the interactions of these ions with solids. The role of the proximity of the protons, molecular ion fragments, upon the amplitude of these collective effects is evidenced from the study of the statistics of forward emission. These experiences allowed us to shed light on various aspects of atom and polyatomic ion inter-actions with solid surfaces. (author)

  13. Measurement of ion species produced due to bombardment of 450 eV N{sub 2}{sup +} ions with hydrocarbons-covered surface of tungsten: Formation of tungsten nitride

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Bhatt, P. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Kumar, A. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Singh, B.K.; Singh, B.; Prajapati, S. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Shanker, R., E-mail: shankerorama@gmail.com [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India)

    2016-08-01

    A laboratory experiment has been performed to study the ions that are produced due to collisions of 450 eV N{sub 2}{sup +} ions with a hydrocarbons-covered surface of polycrystalline tungsten at room temperature. Using a TOF mass spectrometry technique, the product ions formed in these collisions have been detected, identified and analyzed. Different ion–surface reaction processes, namely, neutralization, reflection, surface induced dissociation, surface induced chemical reactions and desorption are observed and discussed. Apart from the presence of desorbed aliphatic hydrocarbon and other ions, the mass spectra obtained from the considered collisions show the formation and sputtering of tungsten nitride (WN). A layer of WN on tungsten surface is known to decrease the sputtering of bulk tungsten in fusion devices more effectively than when the tungsten is bombarded with other seeding gases (He, Ar). It is further noted that there is a negligible diffusion of N in the bulk tungsten at room temperature.

  14. 160 MeV Ni12+ ion irradiation effects on the dielectric properties of polyaniline nanotubes

    International Nuclear Information System (INIS)

    Hazarika, J.; Nath, Chandrani; Kumar, A.

    2012-01-01

    We report on the dielectric properties and a.c. conductivity studies of CSA doped polyaniline nanotubes. Nanotubes of 47–100 nm diameter, were synthesized by the self-assembly method and irradiated using Ni 12+ ions of 160 MeV energy with fluences of 1 × 10 10 , 5 × 10 10 , 1 × 10 11 and 3 × 10 11 ions/cm 2 . X-ray diffraction studies reveal an increase in the degree of crystallinity and consequently, the extent of order of the nanotubes with increasing fluence, but show a lower degree of crystallinity at higher fluence. The decrease in d-spacing for the (100) reflections with fluence is ascribed to the decrease in the tilt angle of the aligned polymer chains. A significant change was seen after irradiation in dielectric and electrical properties which may be correlated with the increased carrier concentration and structural modifications in the polymer films. The surface conductivity of films increases with increasing fluence, which also decreases at higher fluence. The a.c. conduction mechanism for the nanotubes could be explained in terms of correlated barrier hopping model. The existence of polarons as the major charge carriers in the present nanotube system was confirmed by the low values of polaron binding energy, found to decrease with fluence. The hopping distance increases with fluence indicating that the hopping probability increases with fluence.

  15. Charge-state distribution in close collisions of 3 MeV C2+ ions with Ag and Au atoms

    NARCIS (Netherlands)

    Boerma, D.O; Arnoldbik, W.M.; Kabachnik, N.M.; Khodyrev, V.A.

    The charge-state distributions of 3 MeV carbon ions scattered over angles of 40 degrees and 60 degrees from sub-monolayers of Ag and Au atoms evaporated on a substrate and from thick layers of Ag and Au have been measured. A close similarity of the charge distributions in all cases is interpreted as

  16. Fluctuation Induced Conductivity Studies of 100 MeV Oxygen Ion Irradiated Pb Doped Bi-2223 Superconductors

    NARCIS (Netherlands)

    Banerjee, Tamalika; Kumar, Ravi; Kanjilal, D.; Ramasamy, S.

    2000-01-01

    We report on 100 MeV oxygen ion irradiation in Pb doped Bi-2223 superconductors. Resistivity measurements reveal that both grains as well as the grain boundaries are affected by such irradiation. An analysis of the excess conductivity has been made within the framework of Aslamazov-Larkin (AL) and

  17. Influence of helium-ion bombardment on the optical properties of ZnO nanorods/p-GaN light-emitting diodes

    Science.gov (United States)

    Alvi, Naveed Ul Hassan; Hussain, Sajjad; Jensen, Jen; Nur, Omer; Willander, Magnus

    2011-12-01

    Light-emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods grown by vapor-liquid-solid catalytic growth method were irradiated with 2-MeV helium (He+) ions. The fabricated LEDs were irradiated with fluencies of approximately 2 × 1013 ions/cm2 and approximately 4 × 1013 ions/cm2. Scanning electron microscopy images showed that the morphology of the irradiated samples is not changed. The as-grown and He+-irradiated LEDs showed rectifying behavior with the same I-V characteristics. Photoluminescence (PL) measurements showed that there is a blue shift of approximately 0.0347 and 0.082 eV in the near-band emission (free exciton) and green emission of the irradiated ZnO nanorods, respectively. It was also observed that the PL intensity of the near-band emission was decreased after irradiation of the samples. The electroluminescence (EL) measurements of the fabricated LEDs showed that there is a blue shift of 0.125 eV in the broad green emission after irradiation and the EL intensity of violet emission approximately centered at 398 nm nearly disappeared after irradiations. The color-rendering properties show a small decrease in the color-rendering indices of 3% after 2 MeV He+ ions irradiation.

  18. Conceptual study of a heavy-ion-ERDA spectrometer for energies below 6 MeV

    Science.gov (United States)

    Julin, Jaakko; Sajavaara, Timo

    2017-09-01

    Elastic recoil detection analysis (ERDA) is a well established technique and it offers unique capabilities in thin film analysis. Simultaneous detection and depth profiling of all elements, including hydrogen, is possible only with time-of-flight ERDA. Bragg ionization chambers or ΔE - E detectors can also be used to identify the recoiling element if sufficiently high energies are used. The chief limitations of time-of-flight ERDA are the beam induced sample damage and the requirement of a relatively large accelerator. In this paper we propose a detector setup, which could be used with 3 MeV to 6 MeV medium heavy beams from either a single ended accelerator (40Ar) or from a tandem accelerator (39K). The detector setup consists of two timing detectors and a gas ionization chamber energy detector. Compared to use of very heavy low energy ions the hydrogen recoils with this beam have sufficient energy to be detected with current gas ionization chamber energy detector. To reduce the beam induced damage the proposed detector setup covers a solid angle larger than 1 msr, roughly an order of magnitude improvement over most time-of-flight ERDA setups. The setup could be used together with a small accelerator to be used for light element analysis of approximately 50 nm films. The concept is tested with 39K beam from a 1.7 MV Pelletron tandem accelerator with the Jyväskylä ToF-ERDA setup. In addition to the measurements effects related to low energies and increase in the solid angle are simulated with Monte Carlo methods.

  19. Capacitance-voltage investigation of silicon photodiodes damaged by MeV energy light ions

    International Nuclear Information System (INIS)

    Kalinka, G.; Simon, A.; Novak, M.; Kiss, A.Z.

    2006-01-01

    Complete text of publication follows. Nuclear radiation creates not only deep centers, but in addition influences shallow dopant concentration in semiconductors, as well. At a given temperature the maximum frequency a center can respond to depends on its energy level, therefore the capacitance-voltage (C-V) characteristics of radiation damaged semiconductor diodes should ideally be measured as function of frequency in order to obtain the physical and energy depth distribution of ionized centers [1,2]. In our experiments C-V plots of MeV energy ion irradiated photodiodes were taken at fixed 1 kHz frequency, which is low enough to be sensitive at room temperature to some of the deep levels expected. During, for example, an irradiation with 5.5 MeV α particles the capacitance of a p + nn + diode increased significantly at low voltages, but showed rather small changes at higher ones. The former turned out to be merely related to a decrease of the built in voltage, corresponding to a lifetime to relaxation type transition of the semiconductor [3]. Rescaling C-V data for this change, the remaining, actual capacitance changes could be interpreted as related to nuclear recoil caused damage located around the end of particle tracks. C-V technique has also been used for follow up investigation of spontaneous self annealing at room temperature of irradiated samples. This is shown here by plotting capacitance data normalized to their virgin values as function of depletion depth for irradiation with 430 keV protons, whose range is about 5 μm. The sensitivity of the method is illustrated for low fluence of 6.5 MeV oxygen, whose range is 5 μm, too, and where the normalization is now made to data taken one week after the irradiation. Acknowledgement This work was supported by the Hungarian Research and Technology Innovation Fund and the Croatian Ministry of Science, Education and Sports within the framework of the Hungarian-Croatian Intergovernmental Science and Technology Co

  20. Ion beam synthesis of IrSi3 by implantation of 2 MeV Ir ions

    International Nuclear Information System (INIS)

    Sjoreen, T.P.; Chisholm, M.F.; Hinneberg, H.J.

    1992-11-01

    Formation of a buried IrSi 3 layer in (111) oriented Si by ion implantation and annealing has been studied at an implantation energy of 2 MeV for substrate temperatures of 450--550C. Rutherford backscattering (RBS), ion channeling and cross-sectional transmission electron microscopy showed that a buried epitaxial IrSi 3 layer is produced at 550C by implanting ≥ 3.4 x 10 17 Ir/cm 2 and subsequently annealing for 1 h at 1000C plus 5 h at 1100C. At a dose of 3.4 x 10 17 Ir/cm 2 , the thickness of the layer varied between 120 and 190 nm and many large IrSi 3 precipitates were present above and below the film. Increasing the dose to 4.4 x 10 17 Ir/cm 2 improved the layer uniformity at the expense of increased lattice damage in the overlying Si. RBS analysis of layer formation as a function of substrate temperature revealed the competition between the mechanisms for optimizing surface crystallinity vs. IrSi 3 layer formation. Little apparent substrate temperature dependence was evident in the as-implanted state but after annealing the crystallinity of the top Si layer was observed to deteriorate with increasing substrate temperature while the precipitate coarsening and coalescence improved

  1. Studies on the bombardment of condensed molecular gases at liquid-He temperatures by keV electrons and light ions

    International Nuclear Information System (INIS)

    Boergesen, P.

    1982-09-01

    Films of solid H 2 , D 2 and N 2 were irradiated with keV electrons and ions. Stopping cross sections and ranges of 0.3-10 keV/amu light ions in solid H 2 and D 2 are in good agreement with experimental and theoretical data on gaseous targets. In contrast, both stopping cross section and range measurements in solid N 2 suggest that the stopping here is only about half of that in N 2 -gas. This ''phase-effect'' is further supported by secondary emission measurements. Secondary electron emission coefficients for 2-10 keV H 1 + , H 2 + , H 3 + , D 3 + , D 2 H + , 4 He + , 14 N + and 20 Ne + incident on solids H 2 , D 2 and N 2 are in reasonable agreement with previous results for electron-incidence. The rather large erosion yields for 1-3 keV electrons incident on solid D 2 depend strongly on target thickness (for thin films), but weakly on energy. Bulk yields for 2 keV electrons were approximately 8 H 2 /electron, approximately 4 D 2 /electron and approximately 0.5 N 2 /electron. Secondary ion emission during ion bombardment seems to be predominantly reflected projectiles in the case of N 2 -targets, while it may be explained as sputtered particles from H 2 - and D 2 -targets. Preliminary results on the erosion of solid H 2 and D 2 by keV light ions indicate very large erosion yields (approx. 400 H 2 /atom for 2 keV protons) increasing strongly with energy. (Auth.)

  2. Doubly versus Singly Positively Charged Oxygen Ions Back-Scattering from a Silicon Surface under Dynamic O2+ Bombardment

    Czech Academy of Sciences Publication Activity Database

    Franzreb, K.; Williams, P.; Lörinčík, Jan; Šroubek, Zdeněk

    203-204, 1/4 (2003), s. 39-42 ISSN 0169-4332 Institutional research plan: CEZ:AV0Z2067918; CEZ:AV0Z4040901 Keywords : low-energy ion scattering * doubly charged ions * molecular orbital Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.284, year: 2003

  3. Secondary emission from a CuBe target due to bombardment with parent and fragment ions of ammonia and phosphine

    International Nuclear Information System (INIS)

    Maerk, T.D.

    1977-01-01

    The secondary electron emission of the first dynode of a CuBe alloy sixteen dynode electron multiplier has been studied in the course of electron impact ionization studies of ammonia and phosphine. Relative secondary electron emission coefficients have been obtained for the singly and doubly charged parent and fragment ions of ammonia, ammonia-d 3 , phosphine and phosphine-d 3 for kinetic energies of 5,25 and 10,5 keV. It has been found, that in general deuterated ions have smaller γ coefficients, that ammonia ions have larger γ coefficients than corresponding phosphine ions, and that the γ coefficients increase with the complexity of the ion under study. (Auth.)

  4. Development of the integrated control system for the microwave ion source of the PEFP 100-MeV proton accelerator

    Science.gov (United States)

    Song, Young-Gi; Seol, Kyung-Tae; Jang, Ji-Ho; Kwon, Hyeok-Jung; Cho, Yong-Sub

    2012-07-01

    The Proton Engineering Frontier Project (PEFP) 20-MeV proton linear accelerator is currently operating at the Korea Atomic Energy Research Institute (KAERI). The ion source of the 100-MeV proton linac needs at least a 100-hour operation time. To meet the goal, we have developed a microwave ion source that uses no filament. For the ion source, a remote control system has been developed by using experimental physics and the industrial control system (EPICS) software framework. The control system consists of a versa module europa (VME) and EPICS-based embedded applications running on a VxWorks real-time operating system. The main purpose of the control system is to control and monitor the operational variables of the components remotely and to protect operators from radiation exposure and the components from critical problems during beam extraction. We successfully performed the operation test of the control system to confirm the degree of safety during the hardware performance.

  5. Net sputtering rate due to hot ions in a Ne-Xe discharge gas bombarding an MgO layer

    International Nuclear Information System (INIS)

    Ho, S.; Tamakoshi, T.; Ikeda, M.; Mikami, Y.; Suzuki, K.

    2011-01-01

    An analytical method is developed for determining net sputtering rate for an MgO layer under hot ions with low energy ( h i , above a threshold energy of sputtering, E th,i , multiplied by a yield coefficient. The threshold energy of sputtering is determined from dissociation energy required to remove an atom from MgO surface multiplied by an energy-transfer coefficient. The re-deposition rate of the sputtered atoms is calculated by a diffusion simulation using a hybridized probabilistic and analytical method. These calculation methods are combined to analyze the net sputtering rate. Maximum net sputtering rate due to the hot neon ions increases above the partial pressure of 4% xenon as E h Ne becomes higher and decreases near the partial pressure of 20% xenon as ion flux of neon decreases. The dependence due to the hot neon ions on partial pressure and applied voltage agrees well with experimental results, but the dependence due to the hot xenon ions deviates considerably. This result shows that the net sputtering rate is dominated by the hot neon ions. Maximum E h Ne (E h Ne,max = 5.3 - 10.3 eV) is lower than E th,Ne (19.5 eV) for the MgO layer; therefore, weak sputtering due to the hot neon ions takes place. One hot neon ion sputters each magnesium and each oxygen atom on the surface and distorts around a vacancy. The ratio of the maximum net sputtering rate is approximately determined by number of the ions at E h i,max multiplied by an exponential factor of -E th,i /E h i,max .

  6. Monte Carlo simulation of channeled and random profiles of heavy ions implanted in silicon at high energy (1.2 MeV)

    International Nuclear Information System (INIS)

    Mazzone, A.M.

    1987-01-01

    In order to study channeling effects and implants of heavy ions with energy of few MeV in silicon, ion distributions are calculated with a Monte Carlo method for axial [(001) axis], planar, and nominally random directions for As + and P + ions implanted into silicon with energies in the range 100 keV to 2 MeV. The calculation indicates an appreciable channeling at the higher energy only for the (001) axis and the (110) planes. For heavy ions with energy in the MeV range the subsidence of channeling into major channels and the disappearance of minor channels are shown

  7. In situ MeV ion beam analysis of ceramic surfaces modified by 100-400 keV ion irradiation

    International Nuclear Information System (INIS)

    Weber, W.J.; Yu, N.; Sickafus, K.E.

    1995-05-01

    This paper describes use of the in situ ion beam analysis facility developed at Los Alamos National Laboratory for the study of irradiation effects in ceramic materials. In this facility, an analytical beamline of 3 MV tandem accelerator and an irradiation bean-dine of 200 kV ion implanter are connected at 60 degrees to a common target chamber. This facility provides a fast, efficient, and quantitative measurement tool to monitor changes of composition and crystallinity of materials irradiated by 100-400 keV ions, through sequential measurement of backscattering events of MeV ions combined with ion channeling techniques. We will describe the details of the in situ ion beam analysis and ion irradiation and discuss some of the important issues and their solutions associated with the in situ experiment. These issues include (1) the selection of axial ion channeling direction for the measurement of radiation damage; (2) surface charging and charge collection for data acquisition; (3) surface sputtering during ion irradiation; (4) the effects of MeV analytical beam on the materials; and (5) the sample heating effect on ion beam analysis

  8. Light-Ion Production in the Interaction of 96 MeV Neutrons with Silicon

    International Nuclear Information System (INIS)

    Tippawan, U.; Dangtip, S.; Pomp, S.; Atac, A.; Bergenwall, B.; Blomgren, J.; Hildebrand, A.; Johansson, C.; Klug, J.; Mermod, P.; Oesterlund, M.; Nilsson, L.; Elmgren, K.; Olsson, N.; Jonsson, O.; Prokofiev, A.V.; Renberg, P.-U.; Nadel-Turonski, P.; Corcalciuc, V.; Watanabe, Y.

    2005-01-01

    Radiation effects induced by terrestrial cosmic rays in microelectronics, on board aircrafts as well as at sea level, have recently attracted much attention. The most important particle radiation is due to spallation neutrons, created in the atmosphere by cosmic-ray protons. When, e.g., an electronic memory circuit is exposed to neutron radiation, charged particles can be produced in a nuclear reaction. The charge released by ionization can cause a flip of the memory content in a bit, which is called a single-event upset (SEU). This induces no hardware damage to the circuit, but unwanted re-programming of memories, CPUs, etc., can have consequences for the reliability, and ultimately also for the safety of the system.Data on energy and angular distributions of the secondary particles produced by neutrons in silicon nuclei are essential input for analyses and calculation of SEU rate. In this work, double-differential cross sections of inclusive light-ion (p, d, t, 3He and α) production in silicon, induced by 96 MeV neutrons, are presented. Energy distributions are measured at eight laboratory angles from 20 deg. to 160 deg. in steps of 20 deg. Deduced energy-differential and production cross sections are reported as well. Experimental cross sections are compared to theoretical reaction model calculations and existing experimental data in the literature

  9. Strain buildup in GaAs due to 100 MeV Ag ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Shramana; Bhaumik, Sudipta; Panda, Jaya Kumar [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721 302 (India); Ojha, Sunil [Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Dhar, Achintya [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721 302 (India); Kabiraj, D. [Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Roy, Anushree, E-mail: anushree@phy.iitkgp.ernet.in [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721 302 (India)

    2013-12-01

    The formation of strained layers and a non-monotonic evolution of strain in high energy (100 MeV) silver ion (Ag{sup 7+}) irradiated undoped semi-insulating GaAs are observed and analyzed using Raman scattering and high resolution X-ray diffraction (HRXRD) measurements. At low fluence, compressively strained layers are formed, whereas, with increase in fluence both compressive and tensile strains appear as observed from HRXRD measurements. Further, at low fluence, the change in compressive strain with increase in fluence is found to be sharper than what is observed at higher fluence, thereby suggesting a critical fluence value, beyond which there is a simultaneous generation and annihilation of vacancy type defects. The initial blue shift and subsequent relative red shift beyond above critical fluence in the Raman peak also qualitatively reveal non-monotonic evolution of strain in this case. Finally, we demonstrate the sensitivity of Raman spectroscopy in detecting the decrease in lattice ordering in the crystal in the low fluence regime, below the detection limit of Rutherford back-scattering channeling (c-RBS) measurements.

  10. Evaluation of electon and nuclear bremsstrahlung in heavy ion collisions

    International Nuclear Information System (INIS)

    Gippner, P.

    1975-01-01

    The detection of quasimolecular X-ray continua provides the possibility of investigating the electron shells of quasimolecules transiently formed during adiabatic heavy ion-atomic collision. The contribution of the electron and nuclear bremsstrahlung to quasimolecular X-ray continua observed in bombarding various targets with 65 and 96 MeV Nb ions were estimated

  11. Alpha-heavy-ion angular correlations from /sup 28/Si + /sup 12/C. [84 to 91. 5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Ost, R; Cole, A J [Institut des Sciences Nucleaires, 38 - Grenoble (France); Clover, M R; Fulton, B R; Sikora, B [Rochester Univ., NY (USA). Nuclear Structure Research Lab.

    1980-06-01

    Alpha particles have been measured in coincidence with heavy recoil nuclei from the /sup 28/Si + /sup 12/C reaction. At Esub(lab) = 87 MeV angular correlations for alphas between 15/sup 0/ and 55/sup 0/ and heavy ions at angles -9/sup 0/, -12/sup 0/ and -15/sup 0/ have been taken. An excitation function of coincidence events with THETAsub(..cap alpha..) = 30/sup 0/ and THETAsub(HI) = -12/sup 0/ has been measured for 84 MeV < Esub(lab) < 91.5 MeV. The results are well described by a statistical-model calculation for compound nucleus decay. No evidence is found for additional processes.

  12. High energy (MeV) ion beam modifications of sputtered MoS2 coatings on sapphire

    International Nuclear Information System (INIS)

    Bhattacharya, R.S.; Rai, A.K.; Erdemir, A.

    1991-01-01

    The present article reports on the results of our investigations of high-energy (MeV) ion irradiation on the microstructural and tribological properties of dc magnetron sputtered MoS 2 films. Films of thicknesses 500-7500 A were deposited on NaCl, Si and sapphire substrates and subsequently ion irradiated by 2 MeV Ag + ions at a dose of 5x10 15 cm -2 . Scanning and transmission electron microscopy. Rutherford backscattering and X-ray diffraction techniques were utilized to study the structural, morphological and compositional changes of the film due to ion irradiation. The friction coefficient and sliding life were determined by pin-on-disc tests. Both as-deposited and ion-irradiated films were found to be amorphous having a stoichiometry of MoS 1.8 . A low friction coefficient in the range 0.03-0.04 was measured for both as-deposited and ion-irradiated films. However, the sliding life of ion-irradiated film was found to increase more than tenfold compared to as-deposited films indicating improved bonding at the interface. (orig.)

  13. Experimental and calculated effectiveness of a radiochromic dye film to stopping 21 MeV 7Li and 64 MeV 16O ions

    International Nuclear Information System (INIS)

    Olsen, K.J.; Hansen, J.W.

    1984-01-01

    Relative radiation effectiveness, RE, of 21 MeV 7 Li and 64 MeV 16 O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a delta-ray theory for heavy charged particles developed by Katz et al. The experiment was designed to test calculations particularly in the Bragg-peak region of the slowing down particles where significant deviation between theory and experiment was found. Fitting of the characteristic D 37 dose and the size of the radiation sensitive element in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the delta-ray spectrum and the slowing down spectrum of electrons from low-LET radiation, and partly from approximations in the calculated distribution of energy deposition of the delta-rays. (orig.)

  14. Effect of radical species density and ion bombardment during ashing of extreme ultralow-κ interlevel dielectric materials

    International Nuclear Information System (INIS)

    Worsley, M. A.; Bent, S. F.; Fuller, N. C. M.; Tai, T. L.; Doyle, J.; Rothwell, M.; Dalton, T.

    2007-01-01

    The significance of ion impact and radical species density on ash-induced modification of an extreme ultralow-κ interlevel dielectric (ILD) material (κ 2 and Ar/N 2 dual frequency capacitive discharges is determined by combining plasma diagnostics, modeling of the ion angular distribution function, and material characterization such as angle resolved x-ray photoelectron spectroscopy. Radical species density was determined by optical emission actinometry under the same conditions and in the same reactor in a previous study by the present authors. ILD modification is observed and correlated with changes in the plasma for a range of pressures (5-60 mTorr), bias powers (0-350 W), and percent Ar in the source gas (0%, 85%). For the Ar/O 2 discharge, extensive modification of the ILD sidewall was observed for significant ion scattering conditions, whereas minimal modification of the ILD sidewall was observed under conditions of minimal or no ion scattering. Further, for an identical increase in the O-radical density (∼ an order of magnitude), a different degree of modification was induced at the ILD trench bottom surface depending on whether pressure or percent Ar was used to increase the radical density. The different degrees of modification seemingly correlated with the relative changes in the ion current for increasing pressure or percent Ar. For the Ar/N 2 discharge, reduced damage of the ILD sidewall and trench bottom surfaces was observed for increasing pressure (increasing N-radical density) and decreasing ion current to both surfaces. It is, thus, proposed that the mechanism for modification of the porous ILD is dominated by the creation of reactive sites by ion impact under the present conditions. A detailed discussion of the results which support this proposal is presented

  15. EPR and cathodoluminescence of defects in diamond irradiated by nickel ions with energy of 335 MeV

    International Nuclear Information System (INIS)

    Varichenko, V.S.; Martinovich, V.A.; Filipp, A.Z.; Didyk, A.Yu.

    1995-01-01

    Defect production in natural diamond irradiated by 335 MeV Ni ions within a dose range of 5·10 12 - 5·10 14 cm -2 has been studied by EPR and cathodoluminescence techniques. It is shown that the high energy ion irradiation leads to the appearance of modified track like one-dimensional structures with nontetrahedral coordination of atoms. A mechanism of microwave conductivity in modified structures of irradiated samples discussed in frame of a model of mobile quasi-particles of corresponding paramagnetic centres. Peculiarities of concentration distributions of paramagnetic centres corresponding to ion-modified structures and cathodoluminescence centres through the irradiated layer are connected with track channeling and stopped of a part of ions because of their elastic collisions with lattice atoms during ion stopping. (author). 18 refs., 5 figs

  16. 0.5 to 6 MeV Ar ion induced X-ray emission in view to analytical application

    International Nuclear Information System (INIS)

    Tenorio Castilleros, M.D.

    1979-01-01

    A study of the X-ray emission induced by 0.5 to 6 MeV Ar ions has been realized in view of multielemental analytical applications. The historical development of the use of heavy ion induced X-ray emission in analysis and the theoretical background of inner-shell ionization in heavy ion-atom collisions are described. The emission of non characteristic X-rays and the effects related to the penetration of heavy ions in matter are also related. The experimental part contains a description of the experimental devices and of the X-ray spectra fitting method. Thick target yields as a function of the target Z and the Ar ion energy are reported. The analytical possibilities are examined and an application to the analysis of Si and Cl in cadmium telluride crystals is given [fr

  17. Role of Ion Bombardment, Film Thickness and Temperature of Annealing on PEC Activity of Very-thin Film Hematite .

    Czech Academy of Sciences Publication Activity Database

    Kment, Š.; Čada, M.; Hubička, Z.; Krýsa, J.; Kmentová, Hana; Olejníček, J.; Zlámalová Cílová, Z.; Zbořil, R.

    2016-01-01

    Roč. 41, č. 27 (2016), s. 11547-11557 ISSN 0360-3199. [International Conference on Hydrogen Energy /1./. Aveiro, 20.07.2015-22.07.2015] Institutional support: RVO:67985858 Keywords : ion flux density * hematite photoanode * thin films Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.582, year: 2016

  18. Charge-state distributions of 100, 175, 275, and 352 MeV gold ions emerging from thin carbon foils

    International Nuclear Information System (INIS)

    Martin, J.A.; Auble, R.L.; Erb, K.A.; Jones, C.M.; Olsen, D.K.

    1985-01-01

    These measurements were undertaken as a consequence of our failure early this year to accelerate Au +46 ions in the Oak Ridge Isochronous Cyclotron using an injected beam of 352 MeV 197 Au +17 from the 25 MV tandem accelerator. Following that unsuccessful test, we made a preliminary measurement of the charge-state distribution of 352 MeV 197 Au ions emerging from a carbon foil using the bending magnet that is a part of the cyclotron beam injection system. The measured mean charge was approx.38.5, about 4.5 charge-states lower than predicted by the Sayer semi-empirical formula. The measurements reported here were done more precisely and systematically confirm that preliminary result. 12 refs., 5 figs., 4 tabs

  19. Charge-state distributions of 100, 175, 275, and 352 MeV gold ions emerging from thin carbon foils

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.A.; Auble, R.L.; Erb, K.A.; Jones, C.M.; Olsen, D.K.

    1985-01-01

    These measurements were undertaken as a consequence of our failure early this year to accelerate Au/sup +46/ ions in the Oak Ridge Isochronous Cyclotron using an injected beam of 352 MeV /sup 197/Au/sup +17/ from the 25 MV tandem accelerator. Following that unsuccessful test, we made a preliminary measurement of the charge-state distribution of 352 MeV /sup 197/Au ions emerging from a carbon foil using the bending magnet that is a part of the cyclotron beam injection system. The measured mean charge was approx.38.5, about 4.5 charge-states lower than predicted by the Sayer semi-empirical formula. The measurements reported here were done more precisely and systematically confirm that preliminary result. 12 refs., 5 figs., 4 tabs.

  20. K-shell x-ray production cross sections of selected elements Al to Ni for 4. 0 to 38. 0 MeV /sup 10/B ions. [Cross sections, 4. 0 to 38 MeV, binding energy, electron capture decay, PWBA, energy shifts, multiple ionization

    Energy Technology Data Exchange (ETDEWEB)

    Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

    1976-01-01

    K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident /sup 10/B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The K..beta../K..cap alpha.. x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for /sup 10/B bombardment of target elements in the range 21 less than or equal to Z/sub 2/ less than or equal to 28.

  1. Stripping of 1.04 MeV per nucleon krypton ions in high molecular weight vapours

    International Nuclear Information System (INIS)

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

    1976-01-01

    Equilibrium charge state distributions have been measured for 1.04 MeV per nucleon krypton ions in heavy vapours with molecular weights from 462 to 6500. Non-equilibrium data are presented for the heaviest vapour. A maximum increase of 0.8 in the mean charge is found relative to a conventional diatomic gas but the pressures required are two orders of magnitude less. (Auth.)

  2. Neutron radiation field due to 6.6 MeV/amu 58Ni ions bombarding a thick Cu target

    International Nuclear Information System (INIS)

    Aleinikov, V.E.; Cherevatenko, A.P.; Clapier, F.B.; Tsovbun, V.I.

    1985-01-01

    The angular distribution of the dose equivalent rate and neutron spectra were obtained using the Bonner sphere spectrometry method. The quality factor was measured by a tissue-equivalent Rem-2 chamber at several angles. The agreement between the results of the measurements and an empirical parameterisation of the angular distribution is satisfactory. The total yield is estimated to be 1.6+-0.4x10 -3 neutrons per heavy ion. (author)

  3. Nonlinear optical waveguides produced by MeV ion implantation in LiNbO3

    International Nuclear Information System (INIS)

    Sarkisov, S.S.; Curley, M.J.; Williams, E.K.; Ila, D.; Svetchnikov, V.L.; Zandbergen, H.W.; Zykov, G.A.; Banks, C.; Wang, J.-C.; Poker, D.B.; Hensley, D.K.

    2000-01-01

    We analyze microstructure, linear and nonlinear optical properties of planar waveguides produced by implantation of MeV Ag ions into LiNbO 3 . Linear optical properties are described by the parameters of waveguide propagation modes and optical absorption spectra. Nonlinear properties are described by the nonlinear refractive index. Operation of the implanted crystal as an optical waveguide is due to modification of the linear refractive index of the implanted region. The samples as implanted do not show any light-guiding. The implanted region has amorphous and porous microstructure with the refractive index lower than the substrate. Heat treatment of the implanted samples produces planar light-guiding layer near the implanted surface. High-resolution electron microscopy reveals re-crystallization of the host between the surface and the nuclear stopping region in the form of randomly oriented crystalline grains. They make up a light-guiding layer isolated from the bulk crystal by the nuclear stopping layer with low refractive index. Optical absorption of the sample as implanted has a peak at 430 nm. This peak is due to the surface plasmon resonance in nano-clusters of metallic silver. Heat treatment of the samples shifts the absorption peak to 545 nm. This is more likely due to the increase of the refractive index back to the value for the crystalline LiNbO 3 . The nonlinear refractive index of the samples at 532 nm (of the order of 10 -10 cm 2 W -1 ) was measured with the Z-scan technique using a picosecond laser source. Possible applications of the waveguides include ultra-fast photonic switches and modulators

  4. Electron angular distributions in He single ionization impact by H2+ ions at 1 MeV

    International Nuclear Information System (INIS)

    Zhang Shaofeng; Ma Xinwen; Suske, J; Fischer, D; Kuehnel, K U; Voitkiv, A; Najjaril, B; Krauss, A; Moshammer, R; Ullrich, J; Hagmann, S

    2009-01-01

    For the first time we investigated in a kinematically complete experiment the ionization of helium in collisions with H 2 + -molecular ions at 1 MeV. Using two separate detectors, the orientation of the projectile H 2 + -molecular ions was determined at the instance of the collision. The electron angular distribution was measured by a R eaction Microscope . The observed structures are found in agreement with theoretical calculations, indicating that the ionized electron of He shows a slight preferential emission direction parallel to the molecular axis.

  5. Dose as a function of radial distance from a 930 MeV 4He ion beam

    International Nuclear Information System (INIS)

    Varma, M.N.; Paretzke, H.; Baum, J.W.; Lyman, J.T.; Howard, J.

    1975-01-01

    A unique mesh wall ionization chamber (approximating a wall-less ionization chamber) was used to measure dose as a function of radial distance from a 930 MeV 4 He ion beam in air. Measurements were made at distances from about 10 to 40 cm from the ion path. This represents simulated distances of approximately 102 to 404 μm in tissue having a density of 1 g/cm 3 . Experimental values are compared with theoretical calculations, and probable causes of differences found are discussed. (auth)

  6. Damage of niobium surfaces caused by bombardment with 4He+ ions of different energies typical for T-20

    International Nuclear Information System (INIS)

    Guseva, M.I.; Gusev, V.; Martynenko, Yu.V.; Das, S.K.; Kaminsky, M.

    1979-01-01

    The aim of the present studies was to study surface damage due to blistering of both annealed and cold-worked niobium (a candidate first wall material for keV) irradiated sequentially with 4 He + ions with energies of 0.5 to 1800 keV for a total dose of 5.0 C/cm 2 . A typical surface of cold-worked Nb after irradiations with 4 He + ions with increasing energy from 0.5 to 90 keV is shown. The blister diameters range from 0.1 μm to 3 μm, and most of the blisters have exfoliated. The blisters fall into several size classes, the two most dominant ones having most probable blister diameters of approx. 0.27 μm and approx. 2.0 μm. The skin thickness of the larger blisters was measured to be approx. 0.23 μm. Also shown is the same area after irradiation with 150-1800-keV 4 He + irradiation for a dose of 0.66 C/cm 2 . A few additional blisters can be seen. A cold-worked Nb surface that was irradiated only with 150-1800-keV 4 He + ions is also shown. It is seen that prior irradiation with 0.5-90-keV 4 He + helped in significantly reducing blistering. For a total dose of 0.5 C/cm 2 , the erosion yield due to helium blistering of Nb ranges from (5.4 +- 2.0) x 10 -3 to (1.5 +- 0.7) x 10 -2 atoms/ion. For the cold-worked Nb target the results indicate clearly that the 4 He + implantations for the energy range from 0.5 to 90 keV help to reduce both the density and diameter of blisters formed by subsequent He-implantation for the energy ranging from 150 to 1800 keV. 2 figures

  7. 120 MeV Ni Ion beam induced modifications in poly (ethylene terephthalate) used in commercial bottled water

    International Nuclear Information System (INIS)

    Kumar, Vijay; Sonkawade, R. G.; Ali, Yasir; Dhaliwal, A. S.

    2012-01-01

    We report the effects of heavy ion irradiation on the optical, structural, and chemical properties of polyethylene terephthalate (PET) film used in commercial bottled water. PET bottles were exposed with 120 MeV Ni ions at fluences varying from 3 x 10 10 to 3 x 10 12 ion/cm 2 . The modifications so induced were analyzed by using UV-Vis, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Substantial decrease in optical band gap is observed with the increase in ion fluence. In the FTIR spectra, most of bands are decreased due the degradation of the molecular structure. XRD measurements show the decrease in peak intensity, which reflects the loss of crystallinity after irradiation.

  8. Ion-source dependence of the distributions of internuclear separations in 2-MeV HeH+ beams

    International Nuclear Information System (INIS)

    Kanter, E.P.; Gemmell, D.S.; Plesser, I.; Vager, Z.

    1981-01-01

    Experiments involving the use of MeV molecular-ion beams have yielded new information on atomic collisions in solids. A central part of the analyses of such experiments is a knowledge of the distribution of internuclear separations contained in the incident beam. In an attempt to determine how these distributions depend on ion-source gas conditions, we have studied foil-induced dissociations of H 2+ , H 3+ , HeH + , and OH 2+ ions. Although changes of ion-source gas compositions and pressure were found to have no measurable influence on the vibrational state populations of the beams reaching our target, for HeH + we found that beams produced in our rf source were vibrationally hotter than beams produced in a duoplasmatron. This was also seen in studies of neutral fragments and transmitted molecules

  9. Physico-chemical modification of polyethersulphone induced by high energy proton, C+ and Ne6+ ions

    International Nuclear Information System (INIS)

    Vinodh Kumar, S.; Biswavarathi, V.; Jal, P.; Dey, K.; Krishna, J.B.M.; Saha, A.

    2004-01-01

    Polyehersulphone (PES) was irradiated with 4 MeV proton, 3.6 MeV C + and 145 MeV Ne 6+ ions at different ion fluences. The ion induced spectral changes were analyzed by UV-visible and fluorescence spectroscopy. The increase in optical absorption, which shifts gradually from near UV to the visible region with increase in fluence for the three different types of bombarding ions was observed. A significant loss in fluorescence intensity with increase in fluence for three different ions was observed. (author)

  10. Optical, structural, and chemical properties of CR-39 implanted with 5.2 MeV doubly charged carbon ions

    Science.gov (United States)

    Ali, Dilawar; Butt, M. Z.; Ishtiaq, Mohsin; Waqas Khaliq, M.; Bashir, Farooq

    2016-11-01

    Poly-allyl-diglycol-carbonate (CR-39) specimens were irradiated with 5.2 MeV doubly charged carbon ions using Pelletron accelerator. Ion dose was varied from 5 × 1013 to 5 × 1015 ions cm-2. Optical, structural, and chemical properties were investigated by UV-vis spectroscopy, x-ray diffractometer, and FTIR/Raman spectroscopy, respectively. It was found that optical absorption increases with increasing ion dose. Absorption edge shifts from UV region to visible region. The measured opacity values of pristine and ion implanted CR-39 range from 0.0519 to 4.7959 mm-1 following an exponential growth (9141%) with the increase in ion dose. The values of direct and indirect band gap energy decrease exponentially with an increase in ion dose by 59% and 71%, respectively. However, average refractive index in the visible region increases from 1.443 to 2.864 with an increase in ion dose, by 98%. A linear relation between band gap energy and crystallite size was observed. Both the number of carbon atoms in conjugation length and the number of carbon atoms per cluster increase linearly with the increase in ion dose. FTIR spectra showed that on C+2 ions irradiation, the intensity of all bands decreases gradually without appearance of any new band, indicating degradation of polymer after irradiation. Raman spectra revealed that the density of -CH2- group decreases on C+2 ions irradiation. However, the structure of CR-39 is completely destroyed on irradiation with ion dose 1 × 1015 and 5 × 1015 ions cm-2.

  11. K-shell x-ray production cross sections of selected elements Al to Ni for 4.0 to 38.0 MeV 10B ions

    International Nuclear Information System (INIS)

    Monigold, G.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Rice, R.; Miller, P.D.

    1976-01-01

    K-Shell x-ray production cross sections for the target elements Sc, Ti, V, Mn, Fe, Co, and Ni were measured for incident 10 B ions over the energy range 4.0 to 38.0 MeV. The cross section data were compared to the theoretical predictions of the binary encounter approximation (BEA); the plane wave born approximation (PWBA); and the PWBA modified to include corrections for increased binding energy (B), Coulomb deflection of the incident ion (C), orbital perturbation due to polarization (P), and relativistic effects (R). In addition, fluorescence yield variations (W/sub K/) and contributions to the cross sections from electron capture (EC) were included. It was found that the predictions of the fully modified PWBA with contributions from electron capture and fluorescence yield variations included provided the best fit to the experimental data over the entire energy range for each target element. The Kβ/Kα x-ray intensity ratios were compared to theoretical values that assume single hole ionization, and the x-ray energy shifts presented as a function of the energy of the incident ion. These two measurements provided confirmation of the occurrence of multiple ionization for 10 B bombardment of target elements in the range 21 less than or equal to Z 2 less than or equal to 28

  12. Effect of 1.2 MeV argon ions irradiation on magnetic properties of ZnO

    International Nuclear Information System (INIS)

    Mishra, D.K.; Mohapatra, Jyoshnarani; Mahato, Banashree; Kumar, P.; Mitra, Amitav; Singh, S.K.; Kanjilal, D.

    2013-01-01

    Room temperature ferromagnetism in 1.2 MeV argon ions irradiated polycrystalline ZnO has been observed. The magnetic contribution in form of saturation magnetization is higher in sample irradiated with ion fluence of 1 × 10 15 ions/cm 2 . However, annealing of the defects at higher fluences of 5 × 10 15 ions/cm 2 reduce the magnetic contribution in comparison to the magnetic contribution of the lower fluences. The X-ray diffraction reveals that the degree of crystallinity decreases with the increase of ion fluences upto 1 × 10 15 ions/cm 2 and further it increases at a fluence of 5 × 10 15 ions/cm 2 . The inhomogeneous arrangement of grains and changes in their sizes with increasing ion fluences decrease the magnetic ordering of the system. The electron probe microstructure analyses and micro-Raman spectra of irradiated samples show in-homogeneity in zinc and oxygen ratio which is one of the causes to show ferromagnetism.

  13. Search for superheavy elements in the bombardment of 248Cm with 48Ca

    International Nuclear Information System (INIS)

    Hulet, E.K.; Lougheed, R.W.; Wild, J.F.; Landrum, J.H.; Stevenson, P.C.; Ghiorso, A.; Nitschke, J.M.; Otto, R.J.; Morrissey, D.J.; Baisden, P.A.; Gavin, B.F.; Lee, D.; Silva, R.J.; Fowler, M.M.; Seaborg, G.T.

    1977-01-01

    We have searched for superheavy elements 110 to 116 with half-lives between 10 4 and 10 8 s in fractions chemically separated after each of a series of bombardments of 248 Cm made with 267-MeV 48 Ca ions. After 6 months of α and spontaneous-fission counting, our results provide no persuasive evidence for the presence of super-heavy elements. The most plausible explanation for not finding the superheavy elements is that they have either short half-lives or very small formation cross sections

  14. Effect of Carbon Concentration on the Sputtering of Carbon-Rich SiC Bombarded by Helium Ions

    Directory of Open Access Journals (Sweden)

    Xinghao Liang

    2018-02-01

    Full Text Available Silicon carbide (SiC is considered as an important material for nuclear engineering due to its excellent properties. Changing the carbon content in SiC can regulate and control its elastic and thermodynamic properties, but a simulation study of the effect of carbon content on the sputtering (caused by the helium ions of SiC is still lacking. In this work, we used the Monte-Carlo and molecular dynamics simulation methods to study the effects of carbon concentration, incidence energy, incident angle, and target temperature on the sputtering yield of SiC. The results show that the incident ions’ energy and angle have a significant effect on sputtering yield of SiC when the carbon concentration in SiC is around 62 at %, while the target temperature has a little effect on the sputtering yield of SiC. Our work might provide theoretical support for the experimental research and engineering application of carbon fiber-reinforced SiC that be used as the plasma-facing material in tokamak fusion reactors.

  15. Spatial variation in void volume during charged particle bombardment: the effects of injected interstitials

    International Nuclear Information System (INIS)

    Lee, E.H.; Mansur, L.K.; Yoo, M.H.

    1979-01-01

    Experimental observations of the void volume at several depths along the range of 4 MeV Ni ions in 316 stainless steel are reported. The specimens were first preconditioned by neutron irradiation at temperatures of 450 and 584 0 C to fluences of approximately 8 x 10 26 n/m -2 . The void volume after ion bombardment to 60 dpa at the peak damage depth is significantly lower at the peak damage depth than in the region between that and the free surface. The ratio of the step height to void volume at the depth of peak energy deposition between regions masked from and exposed to the beam is strongly dependent on bombardment temperature. The reduction of void volume near the peak damage depth is larger for the 584 0 C than for the 450 0 C preconditioned material. These observations are consistent with recent theoretical results which account for the injection of the bombarding ions as self-interstitials. The theory necessary to understand the effect is developed

  16. Charge steering of laser plasma accelerated fast ions in a liquid spray — creation of MeV negative ion and neutral atom beams

    International Nuclear Information System (INIS)

    Schnürer, M.; Abicht, F.; Priebe, G.; Braenzel, J.; Prasad, R.; Borghesi, M.; Andreev, A.; Nickles, P. V.; Jequier, S.; Tikhonchuk, V.; Ter-Avetisyan, S.

    2013-01-01

    The scenario of “electron capture and loss” has been recently proposed for the formation of negative ion and neutral atom beams with up to MeV kinetic energy [S. Ter-Avetisyan, et al., Appl. Phys. Lett. 99, 051501 (2011)]. Validation of these processes and of their generic nature is here provided in experiments where the ion source and the interaction medium have been spatially separated. Fast positive ions accelerated from a laser plasma source are sent through a cold spray where their charge is changed. Such formed neutral atom or negative ion has nearly the same momentum as the original positive ion. Experiments are released for protons, carbon, and oxygen ions and corresponding beams of negative ions and neutral atoms have been obtained. The electron capture and loss phenomenon is confirmed to be the origin of the negative ion and neutral atom beams. The equilibrium ratios of different charge components and cross sections have been measured. Our method is general and allows the creation of beams of neutral atoms and negative ions for different species which inherit the characteristics of the positive ion source

  17. Spin-flip (p,n) reactions on 26Mg, 54Fe, and 56Fe at selected proton bombarding energies in the range of 17 to 25 MeV

    International Nuclear Information System (INIS)

    Aron, D.L.

    1985-06-01

    New data are presented for the 26 Mg(p,n) 26 Al reaction at E/sub p/ = 19.12 and 24.97 MeV, for the 54 Fe(p,n) 54 Co reaction at E/sub p/ = 17.20, 18.60, and 24.60 MeV, and for the 56 Fe(p,n) 56 Co reaction at E/sub p/ = 19.12 and 24.59 MeV. Data were taken with the LLNL Cyclograaff at 16 angles from 3.5 0 to 159.0 0 . A large detector at 23.8 0 with a long neutron flight path collected high resolution spectra. This large detector also collected separate 0 0 high resolution data on the 26 Mg and 56 Fe(p,n) reactions at E/sub p/ = 19 MeV. Absolute differential (p,n) cross sections were extracted for 1 + states in 26 Al, 54 Co, and 56 Co, for the 0 + isobaric analong state (IAS) in 54 Co and 56 Co, for a 2 + state in each residual nucleus, and for the 0.199 MeV 7 + state of 54 Co. No new experimental states were identified. Only relative cross sections were extracted at 0 0 . Experimental angle-integrated cross sections were obtained for all but one state. DWBA79 was used, with the G-matrix effective nucleon-nucleon interaction of Bertsch et al. (with the central triplet-odd component V/sub to/ = O) and the Livermore shell model wave functions to calculate differential (p,n) cross sections to 1 + states and to the 54 Co and 56 Co IAS. Normalization of the DWBA angle-integrated cross sections to measurements for the 54 Co and 56 Co IAS (at E/sub p/ = 24.6 MeV) yielded the renormalized V/sub tau/ = 21.4 +- 2.1 MeV. Normalization of the DWBA angle-integrated cross sections to measurements for the 24.6 MeV 54 Co and 56 Co 1 + states, coupled with the normalization of the wave functions to previously experimentally determined GT strength, yield the renormalized V/sub sigmatau/ = 12.3 +- 1.2 MeV. The experimental Gamow-Teller strength B(GT)/sub exp./ of the T = 1 26 Al state at 9.44 MeV was found to be 0.69; B(GT)/sub exp/ of the T = 1 26 Al state at 10.47 MeV was found to be 0.39

  18. Beam-envelope calculations of space-charge loaded beams in MeV dc ion-implantation facilities

    International Nuclear Information System (INIS)

    Urbanus, W.H.; Bannenberg, J.G.; Doorn, S.; Saris, F.W.; Koudijs, R.; Dubbelman, P.; Koelewijn, W.

    1989-01-01

    MeV dc ion accelerators are being developed that can deliver a beam current up to several hundred micro-amperes. At the low-energy part of the accelerator, the beam transport is space-charge dominated rather than emittance dominated. A system of differential equations has been derived, based on the Kapchinski-Vladimirski equations, which describe the envelope of a space-charge loaded ion beam, taking a longitudinal electrical field in an accelerating tube into account. The equations have been used to design the accelerator of a high-current 1 MV heavy-ion implantation facility. Furthermore, the design of a 2 MV accelerator is presented, which is used for analyzing techniques such as RBS and PIXE. Both facilities are based on single-ended Van de Graaff accelerators. (orig.)

  19. Experimental study of secondary ion emission from bombarded surfaces by heavy ions at nucleon energy between 0.1 and 5 MeV/u

    International Nuclear Information System (INIS)

    Lorthiois, I.

    1983-03-01

    A time of flight mass spectrometer associated with 252 Cf has been built in the laboratory and used to identify organic and biological molecules. A few number of examples is shown. The complex interaction processes between primary ions and several kinds of materials can be more easily studied by using heavy ions from an accelerator. The mass of the primary ions, its velocity and its state charge are known parameters wich can be varied in these experiments. The desorption yields have been measured simultaneously with other parameters (velocity of the primary ions, number of emitted electrons). The velocity dependance of the yield shows the existence of a maximum around 1 cm/ns and no direct correlations have been found between the yield curves and the electronic stopping power (dE/dx). Experimental results are presented for several types of primary ions (Cu, Kr, Ag) and of material deposits [fr

  20. Secondary electron emission from 0.5--2.5-MeV protons and deuterons

    International Nuclear Information System (INIS)

    Thornton, T.A.; Anno, J.N.

    1977-01-01

    Measurement of the secondary electron currents leaving Al, V, Fe, 316 stainless steel, Nb, and Mo foils undergoing 0.5--2.5-MeV proton and deuteron bombardment were made to determine the secondary electron emission ratios for these ions. The measured secondary electron yields were of the order of 1.0, with the deuterons producing generally higher yields than the protons

  1. Tokamak ion temperature and poloidal field diagnostics using 3 MeV protons

    International Nuclear Information System (INIS)

    Heidbrink, W.W.; Strachan, J.D.

    1984-10-01

    The 3 MeV protons created by d(d,p)t fusion reactions in a moderately sized tokamak leave the plasma on trajectories determined by the position of their birth and by the poloidal magnetic field. Pitch-angle resolution of the escaping 3 MeV protons can separately resolve the spatial distribution of the d(d,p)t fusion reactions and the poloidal field distribution inside the tokamak. These diagnostic techniques have been demonstrated on PLT with an array of collimated surface barrier detectors

  2. Effect of 50 MeV Li3+ ion irradiation on electrical characteristics of high speed NPN power transistor

    International Nuclear Information System (INIS)

    Dinesh, C.M.; Ramani; Radhakrishna, M.C.; Dutt, R.N.; Khan, S.A.; Kanjilal, D.

    2008-01-01

    Silicon NPN overlay RF power high speed commercial bipolar junction transistors (BJTs) find applications in military, space and communication equipments. Here we report the effect of 50 MeV Li 3+ ion irradiation in the fluence range 1 x 10 11 -1.8 x 10 12 ions cm -2 on NPN power transistor. The range (R), electronic energy loss (S e ), nuclear energy loss (S n ), total ionizing dose (TID) and total displacement damage (D d ) in the silicon target are calculated from TRIM Monte Carlo Code. Output resistance is 3.568 x 10 4 Ω for unirradiated device and it increases to 6 x 10 7 Ω as the fluence is increased from 1 x 10 11 to 1.8 x 10 12 ions cm -2 . The capacitance of the emitter-base junction of the transistor decreases and dielectric loss of the emitter-base junction increases with increase in ion fluence. The built in voltage of the unirradiated sample is 0.5 V and it shifts to 0.4 V after irradiation at fluence of 1.8 x 10 12 ions cm -2 and the corresponding doping density reduced to 5.758 x 10 16 cm -3 . The charge carrier removal rate varies linearly with the increase in ion fluence

  3. Heavy-ion induced desorption yields of amorphous carbon films bombarded with 4.2 MeV/u lead ions

    CERN Document Server

    Mahner, E; Küchler, D; Scrivens, R; Costa Pinto, P; Yin Vallgren, C; Bender, M

    2011-01-01

    During the past decade, intense experimental studies on the heavy-ion induced molecular desorption were performed in several particle accelerator laboratories worldwide in order to understand and overcome large dynamic pressure rises caused by lost beam ions. Different target materials and various coatings were studied for desorption and mitigation techniques were applied to heavy-ion accelerators. For the upgrade of the CERN injector complex, a coating of the Super Proton Synchrotron (SPS) vacuum system with a thin film of amorphous carbon is under study to mitigate the electron cloud effect observed during SPS operation with the nominal proton beam for the Large Hadron Collider (LHC). Since the SPS is also part of the heavy-ion injector chain for LHC, dynamic vacuum studies of amorphous carbon films are important to determine their ion induced desorption yields. At the CERN Heavy Ion Accelerator (LINAC 3), carbon-coated accelerator-type stainless steel vacuum chambers were tested for desorption using 4.2 Me...

  4. 130 MeV Au ion irradiation induced dewetting on In{sub 2}Te{sub 3} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Matheswaran, P.; Abhirami, K.M.; Gokul, B. [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Sathyamoorthy, R., E-mail: rsathya1959@gmail.com [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Prakash, Jai [Department of Chemistry, M.M.H. College, Ghaziabad 201001 (India); Asokan, K.; Kanjilal, D. [Materials Science Division, Inter University Accelerator Centre, New Delhi 110067 (India)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer In{sub 2}Te{sub 3} phase formed from In/Te bilayer by 130 MeV Au ion irradiation. Black-Right-Pointing-Pointer Lower fluence results mixed phases with initial state of dewetting. Black-Right-Pointing-Pointer At higher fluence, In{sub 2}Te{sub 3} phase with complete dewetting pattern is formed. Black-Right-Pointing-Pointer Thermal spike model is used to explain the inter face mixing phenomena. Black-Right-Pointing-Pointer SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 Multiplication-Sign 10{sup 13} ions/cm{sup 2}. At the higher fluence of 3 Multiplication-Sign 10{sup 13} ions/cm{sup 2}, dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

  5. TL response of Eu activated LiF nanocubes irradiated by 85 MeV carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Salah, Numan, E-mail: nsalah@kau.edu.sa [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alharbi, Najlaa D. [Sciences Faculty for Girls, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Habib, Sami S. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Lochab, S.P. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2015-09-01

    Carbon ions were found to be effective for cancer treatment. These heavy ions have a high relative biological effectiveness compared to those of photons. They have higher linear energy transfer and sharper Bragg peak with a very excellent local tumor control. However, the dose of these swift heavy ions needs to be measured with great accuracy. Lithium fluoride (LiF) is a highly sensitive phosphor widely used for radiation dosimetry. In this work Eu activated LiF nanocubes were exposed to 85 MeV C{sup 6+} ion beam and evaluated for their thermoluminescence (TL) response. Pellet forms of this nanomaterial were exposed to these ions in the fluence range 10{sup 9}–10{sup 13} ions/cm{sup 2}. The obtained result shows a prominent TL glow peak at around 320 °C, which is different than that induced by gamma rays. This glow peak exhibits a linear response in the range 10{sup 9}–10{sup 12} ions/cm{sup 2}, corresponding to the equivalent absorbed doses 0.273–273 kGy. The absorbed doses, penetration depths and main energy loss were calculated using TRIM code based on the Monte Carlo simulation. The supralinearity function and stopping power in this nanomaterial were also studied. The modification induced in the glow curve structure as a result of changing irradiation type might be utilized to use LiF:Eu nanocubes as a dosimeter for mixed filed radiations. Moreover, the wide linear response of LiF:Eu nanocubes along with the low fading are another imperative results suggesting that this nanomaterial might be a good candidate for carbon ions dosimetry.

  6. TL response of Eu activated LiF nanocubes irradiated by 85 MeV carbon ions

    International Nuclear Information System (INIS)

    Salah, Numan; Alharbi, Najlaa D.; Habib, Sami S.; Lochab, S.P.

    2015-01-01

    Carbon ions were found to be effective for cancer treatment. These heavy ions have a high relative biological effectiveness compared to those of photons. They have higher linear energy transfer and sharper Bragg peak with a very excellent local tumor control. However, the dose of these swift heavy ions needs to be measured with great accuracy. Lithium fluoride (LiF) is a highly sensitive phosphor widely used for radiation dosimetry. In this work Eu activated LiF nanocubes were exposed to 85 MeV C 6+ ion beam and evaluated for their thermoluminescence (TL) response. Pellet forms of this nanomaterial were exposed to these ions in the fluence range 10 9 –10 13 ions/cm 2 . The obtained result shows a prominent TL glow peak at around 320 °C, which is different than that induced by gamma rays. This glow peak exhibits a linear response in the range 10 9 –10 12 ions/cm 2 , corresponding to the equivalent absorbed doses 0.273–273 kGy. The absorbed doses, penetration depths and main energy loss were calculated using TRIM code based on the Monte Carlo simulation. The supralinearity function and stopping power in this nanomaterial were also studied. The modification induced in the glow curve structure as a result of changing irradiation type might be utilized to use LiF:Eu nanocubes as a dosimeter for mixed filed radiations. Moreover, the wide linear response of LiF:Eu nanocubes along with the low fading are another imperative results suggesting that this nanomaterial might be a good candidate for carbon ions dosimetry

  7. Physical and chemical changes induced by 70 MeV carbon ions in polyvinylidene difluoride (PVDF) polymer

    International Nuclear Information System (INIS)

    Virk, H.S.; Chandi, P.S.; Srivastava, A.K.

    2001-01-01

    Physical and chemical changes induced by 70 MeV carbon ions ( 12 C 5+ ) have been investigated in bulk polyvinylidene fluoride (PVDF) polymer. The induced changes have been studied with respect to their optical, chemical and structural response using UV-visible, FTIR and XRD techniques. The ion fluences ranging from 2.5x10 11 to 9x10 13 ions cm -2 have been used to study the irradiation effects. It has been observed that at the fluence of 9x10 13 ions cm -2 the PVDF sample became brittle and practically it was not possible to handle it for any further measurements. The recorded UV-visible spectra show that the optical absorption increases with increasing fluence, indicating maximum absorption at 200 nm. An interesting feature of UV-visible spectra is that dips change into peaks and vice versa with increase of fluence. In the FTIR spectra, development of new peaks at 1714 and 3692 cm -1 along with disappearance of peaks at 2363 and 3025 cm -1 and shifting of peak at 2984-2974 cm -1 have been observed due to high energy irradiation, indicating the chemical changes induced by 12 C 5+ . The diffraction pattern of PVDF indicates that this polymer is semi-crystalline in nature; a large decrease in the diffraction intensity indicates decrease in crystallinity. Increase in crystallite size has also been observed due to heavy ion irradiation

  8. Microstructure and Nano-Hardness of 10 MeV Cl-Ion Irradiated T91 Steel

    International Nuclear Information System (INIS)

    Hu Jing; Wang Xianping; Gao Yunxia; Zhuang Zhong; Zhang Tao; Fang Qianfeng; Liu Changsong

    2015-01-01

    Hardening and elemental segregation of T91 martenstic steel irradiated by 10 MeV Cl ions to doses from 0.06 dpa to 0.83 dpa were investigated with the nanoindentation technique and transmission electron microscopy (TEM). The results demonstrated that the irradiation hardening was closely related with irradiation dose. By increasing the dose, the hardness increased rapidly at first from the initial value of 3.15 GPa before irradiation, and then tended to saturate at a value of 3.58 GPa at the highest dose of 0.83 dpa. Combined with TEM observation, the mechanism of hardening was preliminary attributed to the formation of M(Fe,Cr) 2 3C 6 carbides induced by the high energy Cl-ion irradiation. (paper)

  9. Radiative Auger effect in ion-atom collisions

    International Nuclear Information System (INIS)

    Richard, P.; Oltjen, J.; Jamison, K.A.; Kauffman, R.L.; Woods, C.W.; Hall, J.M.

    1975-01-01

    The radiative Auger effect, RAE, is observed for Al and Si bombarded by 1-2MeV H + . This is the first observation of the RAE X-ray edge using ion excitation. The K-L 23 L 23 RAE edge energy and the relative intensity are in agreement with the previously reported electron and photon induced spectra. (Auth.)

  10. The repetitive flaking of Inconel 625 by 100 keV helium bombardment

    International Nuclear Information System (INIS)

    Whitton, J.L.; Chen, H.M.; Littmark, U.

    1981-01-01

    Repetitive flaking of Inconel 625 occurs with ion bombardment doses of > than 10 18 100 keV helium ions cm -2 , with up to 39 exfoliations being observed after bombardment with 3 x 10 19 ions cm -2 . The thickness of the flakes, measured by scanning electron microscopy, is some 30% greater than when measured by Rutherford backscattering (RBS) of 1.8 MeV helium ions. These RBS measurements compare well with the thickness of the remaining layers in the resultant craters and to the most probable range of the 100 keV helium. The area of the flakes is dictated by the grain boundaries, and when one flake is ejected, the adjacent grains are prevented from doing so since there now exists an escape route for the injected helium. A strong dose rate dependence is observed; decreasing the beam current from 640 μA cm -2 to 64 μA cm -2 results in a factor 20 fewer flakes being exfoliated (for the same total dose of 3 x 10 19 ions cm -2 ). Successive flakes decrease in area, suggesting that eventually a cratered, but stable, surface will result with the only erosion being by the much less effective mechanism of sputtering. (orig.)

  11. Charge-state distribution of MeV He ions scattered from the surface atoms

    International Nuclear Information System (INIS)

    Kimura, Kenji; Ohtsuka, Hisashi; Mannami, Michihiko

    1993-01-01

    The charge-state distribution of 500-keV He ions scattered from a SnTe (001) surface has been investigated using a new technique of high-resolution high-energy ion scattering spectroscopy. The observed charge-state distribution of ions scattered from the topmost atomic layer coincides with that of ions scattered from the subsurface region and does not depend on the incident charge state but depends on the exit angle. The observed exit-angle dependence is explained by a model which includes the charge-exchange process with the valence electrons in the tail of the electron distribution at the surface. (author)

  12. Electronic excitation effects on secondary ion emission in highly charged ion-solid interaction

    International Nuclear Information System (INIS)

    Sekioka, T.; Terasawa, M.; Mitamura, T.; Stoeckli, M.P.; Lehnert, U.; Fehrenbach, C.

    2001-01-01

    In order to investigate the secondary ion emission from the surface of conductive materials bombarded by highly charged heavy ions, we have done two types of experiments. First, we have measured the yield of the sputtered ions from the surface of solid targets of conductive materials (Al, Si, Ni, Cu) bombarded by Xe q+ (q=15-44) at 300 keV (v p =0.30 a.u) and at 1.0 MeV (v p =0.54 a.u). In view of the secondary ion yields as a function of the potential energy of the projectile, the increase rates below q=35, where the potential energy amounts to 25.5 keV, were rather moderate and showed a prominent increase above q=35. These phenomena were rather strong in the case of the metal targets. Second, we have measured the energy dependence of the yield of the sputtered ions from the surface of solid targets of conductive materials (C, Al) bombarded by Xe q+ (q=30,36,44) between 76 keV (v p =0.15 a.u) and 6.0 MeV (v p =1.3 a.u). A broad enhancement of the secondary ion yield has been found for Al target bombarded by Xe 44+ . From these experimental results, the electronic excitation effects in conductive materials for impact of slow highly charged heavy ions bearing high potential energy is discussed

  13. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Laird, J S; Bardos, R A; Saint, A; Moloney, G M; Legge, G F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1994-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  14. Meqalac Results - Multichannel Rf Acceleration of Nitrogen-Ions to 1 Mev

    NARCIS (Netherlands)

    Wojke, R. G. C.; Bannenberg, J. G.; Vijftigschild, A. J. M.; Giskes, F. G.; Ficke, H. G.; Klein, H.; Thomae, R. W.; Schempp, A.; Weis, T.; van Amersfoort, P. W.; Urbanus, W. H.

    1991-01-01

    In the MEQALAC (Multiple Electrostatic Quadrupole Linear Accelerator) multiple N+ ion beams are accelerated in 32 rf gaps, which are part of a modified interdigital-H-resonator operating at 25 MHz. The transverse focusing of the intense ion beams is achieved by means of sets of miniaturized

  15. Scanning deep level transient spectroscopy using an MeV ion microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Laird, J.S.; Bardos, R.A.; Saint, A.; Moloney, G.M.; Legge, G.F.J. [Melbourne Univ., Parkville, VIC (Australia)

    1993-12-31

    Traditionally the scanning ion microprobe has given little or no information regarding the electronic structure of materials in particular semiconductors. A new imaging technique called Scanning Ion Deep Level Transient Spectroscopy (SIDLTS) is presented which is able to spatially map alterations in the band gap structure of materials by lattice defects or impurities. 3 refs., 2 figs.

  16. Production of C, N, O, and Ne ions by pulsed ion source and acceleration of these ions in the cyclotron

    International Nuclear Information System (INIS)

    Nakajima, Hisao; Kohara, Shigeo; Kageyama, Tadashi; Kohno, Isao

    1977-01-01

    The heavy ion source, of electron bombarded hot cathode type, is usually operated by applying direct current for arc discharge. In order to accelerate Ne 6+ ion in the cyclotron, a pulsed operation of this source was attempted. Ne 6+ and O 6+ ions were accelerated successfully up to 160 MeV and more than 0.1 μA of these ion were extracted from the cyclotron. C 5+ , Ne 7+ and 22 Ne 6+ ions were also extracted with a modest intensity of beam. The intensity of C 4+ , N 4+ , N 5+ , and O 5+ ions was increased about ten times. (auth.)

  17. Effect of 120 MeV Ag{sup 9+} ion irradiation of YCOB single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Arun Kumar, R., E-mail: rarunpsgtech@yahoo.com [Crystal Growth Centre, Anna University, Chennai 600 025 (India); Department of Basic Sciences - Physics Division, PSG College of Technology, Coimbatore 641 004 (India); Dhanasekaran, R. [Crystal Growth Centre, Anna University, Chennai 600 025 (India)

    2012-09-15

    Single crystals of yttrium calcium oxy borate (YCOB) grown from boron-tri-oxide flux were subjected to swift heavy ion irradiation using silver Ag{sup 9+} ions from the 15 UD Pelletron facility at Inter University Accelerator Center, New Delhi. The crystals were irradiated at 1 Multiplication-Sign 10{sup 13}, 5 Multiplication-Sign 10{sup 13} and 1 Multiplication-Sign 10{sup 14} ions/cm{sup 2} fluences at room temperature and with 5 Multiplication-Sign 10{sup 13} ions/cm{sup 2} fluence at liquid nitrogen temperature. The pristine and the irradiated samples were characterized by glancing angle X-ray diffraction, UV-Vis-NIR and photoluminescence studies. From the characterization studies performed on the samples, it is inferred that the crystals irradiated at liquid nitrogen temperature had fewer defects compared to the crystals irradiated at room temperature and the defects increased when the ion fluence was increased at room temperature.

  18. Heavy ion elastic and quasi-elastic scattering above E/A = 30 MeV

    International Nuclear Information System (INIS)

    Barrette, J.

    1986-05-01

    At high energy, heavy-ion elastic scattering probes the ion-ion potential in a large domain much inside the strong absorption radius. This results in a more precise determination of the real part of the nuclear potential and a consistent picture of its evolution with energy begins to emerge. It is relatively similar to that observed in light ion scattering. Even if the inelastic angular distributions seem to contain less refractive or interior contribution, coupled channel effects from these states are still important at least up to 20 MeV/n. Heavy-ion induced transfer reactions to discrete states have small cross sections but present a very strong selectivity for states with the highest available spin and could thus provide new and interesting spectroscopic information

  19. Doubly coherent production of π- by 3He ions of 910 MeV

    International Nuclear Information System (INIS)

    Aslanides, E.; Fassnacht, P.; Hibou, F.; Chiavassa, E.; Dellacasa, G.; Gallio, M.; Musso, A.; Bressani, T.; Puddu, G.

    1979-01-01

    The inclusive pion spectrum from the reaction 3 He+ 6 Li → π - +X at 910 MeV was measured at 0 0 with moderate resolution up to the kinematic limit of the two-body final-state reaction. A first analysis shows that the production of high-energy pions cannot be explained by the NN → NNπ process using conventional nucleon momentum distributions. At the end of the spectrum a clear deviation from the general falloff slope is observed and attributed to the doubly coherent reaction 3 He+ 6 Li → 9 C+π -

  20. Ion heating up to 1 MeV range with higher harmonic ICRF wave on JT-60U

    International Nuclear Information System (INIS)

    Nemoto, M.; Kusama, Y.; Hamamatsu, K.; Kimura, H.; Fujii, T.; Moriyama, S.; Saigusa, M.; Afanassiev, V.I.

    1997-01-01

    The properties of protons under accleration by an ion cyclotron range of frequency (ICRF) waves with the second to fourth hydrogen harmonics have been investigated in the JT-60U tokamak at the Japan Atomic Energy Research Institute (JAERI). Protons have been accelerated up to 1 MeV in the presence of an ICRF wave of fixed frequency, neutral beams (NB), and a fixed toroidal magnetic field which is scanned through several plasma discharges. The tail temperature of the protons, which is evaluated in the range 0.32-0.86 MeV, has been observed to increase in the second to third harmonics, however increase of the tail temperature in the third to fourth harmonics has not been observed clearly. Furthermore, the dependence of tail temperature on the harmonic number has been found to be in qualitative agreement with results from a simulation code analysis based upon the one-dimensional Fokker-Planck equation coupled with the kinetic wave equation. Experimental values for the stored energy of the accelerated ions have shown, however, that the response of stored energy to changes in absorbed ICRF power is much stronger than the response to changes in harmonic number. Also, the incremental energy confinement times for heating discharges matching the third and fourth harmonics (3 ω CH) and 4 ω CH) of hydrogen have been observed to be less than half that for those matching the second harmonic. It has been found that suppression of the absorbed ICRF power accompanied with the occurence of cavity resonance in the 3ω CH and 4ω CH heating discharges reduces the stored energy of the accelerated ions and the incremental energy confinement time. (Author)

  1. Simulation of the channelling of ions from MeV C60 in crystalline solids

    International Nuclear Information System (INIS)

    Fetterman, A; Sinclair, L; Tanushev, N; Tombrello, T; Nardi, E

    2007-01-01

    Simulations were performed describing the motion and breakup of energetic C 60 ions interacting with crystalline targets. A hybrid algorithm was used that employs a binary collision model for the scattering of the carbon ions by the atoms of the solid, and molecular dynamics for the Coulomb interactions of the 60 carbon ions with one another. For the case of yttrium iron garnet (YIG), directions such as [1 1 0], [1 0 0], [0 1 0] and [0 0 1] demonstrate channelling for a large fraction of the C ions. For directions such as [1 1 1], [2 1 1] and [7 5 3] the trajectories show no more channelling than for random directions. The effects of tilt, shielding and wake-field interactions were investigated for YIG and α-quartz

  2. Charge state and incident energy dependence of K X-ray emission as a function of target thickness for 50-165 MeV Cu ions incident on 11-250 μg/cm2 Cu

    International Nuclear Information System (INIS)

    Momoi, T.; Shima, K.; Umetani, K.; Moriyama, M.; Ishihara, T.; Mikumo, T.

    1986-01-01

    Thin self-supporting Cu targets in 11-250 μg/cm 2 thickness were bombarded with 50-165 MeV Cu sup(qi + ) ions (7 + )+Cu. From the observed K X-ray yields, K-shell vacancy production cross sections averaged over the target thickness t of projectile sigmasub(KV) and target sigmasup(*)sub(KV) were separately derived taking into account the fluorescence yield that can be estimated from the Ksub(α) X-ray energy shift. When the values of sigmasub(KV) and sigmasup(*)sub(KV) are extrapolated to zero foil thickness, the K shell vacancy formed in the collision has been found to be equally shared between projectile and target in a single collision. With the increase of penetration depth, however, the values of sigmasup(*)sub(KV) are greater than those of sigmasub(KV) presumably due to electron transfer of a target K electron to the projectile K vacancy. The evolution process of projectile excited states as a function of target thickness and the resulting variation of projectile and target K X-ray emissions are discussed. (orig.)

  3. Radiation-induced effects in MgO single crystal by 200 keV and 1 MeV Ni ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ryohei; Nakai, Yoshihiro; Hamaguchi, Dai [Kyoto Inst. of Tech. (Japan); and others

    1997-03-01

    MgO(100) single crystals were implanted with 1.0 MeV and 200 keV Ni ions between 10{sup 15} and 10{sup 17} ions/cm{sup 2} at room temperature. Before and after thermal annealing the radiation damage and the lattice location of implanted Ni ions were analyzed by using Rutherford backscattering spectrometry with channeling and optical absorption measurements. For 1.0 MeV Ni ions, the disorder of Mg atoms increased slowly with ion dose near surface region, while it increased sharply and saturated with ion dose from 2x10{sup 16} ions/cm{sup 2} near ion range. The radiation damage was recovered and implanted Ni ions diffused to the whole of crystal and occupied substitutional positions after 1400degC annealing. For 200 keV Ni ions, the disorder of Mg atoms increased with dose near ion range and had a maximum at about 5x10{sup 16} ions/cm{sup 2}. This tendency agrees with the behavior of color centers obtained from optical measurements. For thermal annealing the radiation damage did not change during 500degC annealing, but the aggregate centers appeared after 300degC annealing. (author)

  4. Measurement of excitation yields of low energy prompt γ-ray from proton bombardment of Cr-foils with energies ranging between 1.0 and 3.0 MeV

    International Nuclear Information System (INIS)

    Goncharov, A.

    2014-01-01

    The goal of this work is measurement of differential cross sections for the production of 378 keV γ-rays from the reactions 52 Cr(p,γ1) 53 Mn and 53 Cr(p,nγ1) 53 Mn for proton energies ranging between 1.0 and 3.0 MeV at the laboratory angle of 90° using foils with thickness ∼1.9×10 18 at/cm 2 (∼ 0.23 μm) of nat Cr.

  5. Polypropylene compositional evolution under 3.5 MeV He{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Abdesselam, M., E-mail: abdesselam_m@yahoo.fr [Faculte de Physique, USTHB, BP32, El Alia, 16111 BEZ (Algeria); Muller, D. [InESS, UMR7163, 23 rue du Loess, BP20, F-67037 Strasbourg Cedex 02 (France); Djebara, M.; Chami, A.C. [Faculte de Physique, USTHB, BP32, El Alia, 16111 BEZ (Algeria); Montgomery, P. [InESS, UMR7163, 23 rue du Loess, BP20, F-67037 Strasbourg Cedex 02 (France)

    2012-05-01

    A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 {mu}m in thickness. The fluence ranges from 2 Multiplication-Sign 10{sup 12} to 3.5 Multiplication-Sign 10{sup 15} cm{sup -2}. The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C({alpha}, {alpha})C) and hydrogen elastic recoil detection (H({alpha}, H){alpha}), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of {approx}5 Multiplication-Sign 10{sup 13} He{sup +} cm{sup -2}. The carbon depletion levels off at a fluence of {approx}5 Multiplication-Sign 10{sup 14} He{sup +} cm{sup -2} approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 Multiplication-Sign 10{sup -16} cm{sup 2}, respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He{sup +} beam is made.

  6. Polypropylene compositional evolution under 3.5 MeV He+ ion irradiation

    International Nuclear Information System (INIS)

    Abdesselam, M.; Muller, D.; Djebara, M.; Chami, A.C.; Montgomery, P.

    2012-01-01

    A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 μm in thickness. The fluence ranges from 2 × 10 12 to 3.5 × 10 15 cm −2 . The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C(α, α)C) and hydrogen elastic recoil detection (H(α, H)α), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of ∼5 × 10 13 He + cm −2 . The carbon depletion levels off at a fluence of ∼5 × 10 14 He + cm −2 approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 × 10 −16 cm 2 , respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He + beam is made.

  7. Polypropylene compositional evolution under 3.5 MeV He+ ion irradiation

    Science.gov (United States)

    Abdesselam, M.; Muller, D.; Djebara, M.; Chami, A. C.; Montgomery, P.

    2012-05-01

    A helium beam at 3.5 MeV was used to induce damage in thin polypropylene film of 5.1 μm in thickness. The fluence ranges from 2 × 1012 to 3.5 × 1015 cm-2. The evolution of the atomic composition (C and H) as a function of the fluence was investigated in situ by forward elastic scattering (C(α, α)C) and hydrogen elastic recoil detection (H(α, H)α), respectively. The helium beam was used at the same time for irradiation and analysis. In respect to the high sensitivity of the polypropylene to radiation damage, the beam current was kept at very low intensity of 0.5 nA. The mass loss becomes significant above a fluence of ˜5 × 1013 He+ cm-2. The carbon depletion levels off at a fluence of ˜5 × 1014 He+ cm-2 approximately while hydrogen loss continues to be present along the whole of the studied fluence range. The final carbon and hydrogen losses, at the highest fluence, are around 17% and 48% of their initial contents, respectively. Satisfactory fits to the release curves have been obtained in the framework of the bulk molecular recombination model (BMR). The deduced hydrogen and carbon release cross sections are 7.8 and 65.2 × 10-16 cm2, respectively. A comparison with our previous measurements of polyethylene terephthalate (PET) film irradiated with 3.7 MeV He+ beam is made.

  8. Effect of 100 MeV swift heavy ions [silver (Ag8+)] on morphological and electrical properties of polypyrrole

    Science.gov (United States)

    Kaur, Amarjeet; Dhillon, Anju; Avasthi, D. K.

    2009-10-01

    Polypyrrole (PPY) films were prepared by the electrochemical polymerization technique. The fully undoped samples were irradiated with different fluences ranging from 1010 to 1012 ions/cm2 of 100 MeV silver (Ag8+) ions. In order to explain the effect of these radiations, a comparative study of samples before and after irradiation was performed by using various techniques such as surface electron microscopy, atomic force microscopy, and X-ray diffraction. With an increase in fluence, the surface structure of PPY films becomes smoother, and the conductivity increases by two orders, which has been explained in light of reordering of polymer chains. The temperature dependence of the dc conductivity of irradiated as well as unirradiated samples has been investigated at 77-300 K. The charge transport properties before and after irradiation are retained although conductivity increases. It has been proposed that swift heavy ion irradiation affects the interchain conductivity. The conductivity of irradiated samples is stable under atmospheric conditions for more than 9 months. The present investigations open up the scope for the applicability of irradiated conducting polymers as microstructures with defined conductivity for sensor applications.

  9. Effect of 100 MeV swift heavy ions [silver (Ag8+)] on morphological and electrical properties of polypyrrole

    International Nuclear Information System (INIS)

    Kaur, Amarjeet; Dhillon, Anju; Avasthi, D. K.

    2009-01-01

    Polypyrrole (PPY) films were prepared by the electrochemical polymerization technique. The fully undoped samples were irradiated with different fluences ranging from 10 10 to 10 12 ions/cm 2 of 100 MeV silver (Ag 8+ ) ions. In order to explain the effect of these radiations, a comparative study of samples before and after irradiation was performed by using various techniques such as surface electron microscopy, atomic force microscopy, and X-ray diffraction. With an increase in fluence, the surface structure of PPY films becomes smoother, and the conductivity increases by two orders, which has been explained in light of reordering of polymer chains. The temperature dependence of the dc conductivity of irradiated as well as unirradiated samples has been investigated at 77-300 K. The charge transport properties before and after irradiation are retained although conductivity increases. It has been proposed that swift heavy ion irradiation affects the interchain conductivity. The conductivity of irradiated samples is stable under atmospheric conditions for more than 9 months. The present investigations open up the scope for the applicability of irradiated conducting polymers as microstructures with defined conductivity for sensor applications.

  10. 125 MeV Si 9+ ion irradiation of calcium phosphate thin film coated by rf-magnetron sputtering technique

    Science.gov (United States)

    Elayaraja, K.; Joshy, M. I. Ahymah; Suganthi, R. V.; Kalkura, S. Narayana; Palanichamy, M.; Ashok, M.; Sivakumar, V. V.; Kulriya, P. K.; Sulania, I.; Kanjilal, D.; Asokan, K.

    2011-01-01

    Titanium substrate was coated with hydroxyapatite by radiofrequency magnetron sputtering (rf-magnetron sputtering) technique and subjected to swift heavy ion (SHI) irradiation of 125 MeV with Si 9+ at fluences of 1 × 10 10, 1 × 10 11 and 1 × 10 12 ions/cm 2. The glancing incidence X-ray diffraction (GIXRD) analysis confirmed the HAp phase of the irradiated film. There was a considerable decrease in crystallinity and particle size after irradiation. In addition, DRS-UV reflectance spectra revealed a decrease in optical band gap ( Eg) from 5.2 to 4.6 eV. Wettability of biocompatible materials plays an important role in biological cells proliferation for tissue engineering, drug delivery, gene transfer and bone growth. HAp thin films irradiated with 1 × 10 11 ions/cm 2 fluence showed significant increase in wettability. While the SHI irradiated samples exhibited enhanced bioactivity, there was no significant variation in cell viability. Surface roughness, pores and average particle size were analyzed by atomic force microscopy (AFM).

  11. Three-dimensional recoil-ion momentum analyses in 8.7 MeV O7+-He collisions

    International Nuclear Information System (INIS)

    Kambara, T.; Tang, J.Z.; Awaya, Y.

    1995-01-01

    Using high-resolution recoil-ion momentum spectroscopy we have measured the differential cross sections of single-electron capture and target single-ionization processes for 8.7 MeV O 7+ -He collisions as functions of scattering angle. A transverse momentum resolution of ±0.2 au, which corresponds to an angular resolution of about ±1.5x10 -6 rad for the projectile scattering angle, was obtained by intersecting a well collimated O 7+ beam with a target of a supersonic He jet from a pre-cooled gas and by measuring the recoil-ion transverse momentum. For the single capture reaction, information on the n-value of the electron final state in O 6+ (1snl) is obtained from the longitudinal momentum of the recoil ions. In pure single-electron capture, the dominant contributions to capture were found to be those from the n=4 and higher states, whereas single capture accompanied by the ionization of the second target electron mainly populates n=2 to n=4 states. Furthermore, the measured transverse momentum distribution differs significantly between pure single capture and capture with simultaneous ionization. The measured data for the pure capture process compare favourably with theoretical results based on a molecular-state expansion method. Other experimental data are discussed in terms of the classical overbarrier model. (author)

  12. Mechanical properties of MeV ion-irradiated SiC/SiC composites characterized by indentation technique

    International Nuclear Information System (INIS)

    Park, J.Y.; Park, K.H.; Kim, W.; Kishimoto, H.; Kohyama, A.

    2007-01-01

    Full text of publication follows: SiC/SiC composites have been considered as a structural material for advanced fusion concepts. In the core of fusion reactor, those SiC/SiC composites are experienced the complex attacks such as strong neutron, high temperature and transmuted gases. One of the vital data for designing the SiC/SiC composites to the fusion reactor is mechanical properties under the severe neutron irradiation. In this work, various SiC/SiC composites were prepared by the different fabrication processes like CVI (chemical vapor infiltration), WA-CVI (SiC whisker assisted CVI) and hot-pressed method. The expected neutron irradiation was simulated by a silicon self-ion irradiation at a DuET facility; Dual-beam for Energy Technologies, Kyoto University. The irradiation temperature were 600 deg. C and 1200 deg. C, and the irradiation does were 5 dpa and 20 dpa, respectively. The 5.1 MeV Si ions were irradiated to the intrinsic CVI-SiC, SiC whisker reinforced SiC and SiC composites produced by hot-press method. The mechanical properties like hardness, elastic modulus and fracture toughness were characterized by an indentation technique. The ion irradiation caused the increase of the hardness and fracture toughness, which was dependent on the irradiation temperature. SiC whisker reinforcement in the SiC matrix accelerated the increase of the fracture toughness by the ion irradiation. For SiC/SiC composites after the ion irradiation, this work will provide the additional data for the mechanical properties as well as the effect of SiC whisker reinforcement. (authors)

  13. Augmentation of thermoelectric performance of VO2 thin films irradiated by 200 MeV Ag9+-ions

    International Nuclear Information System (INIS)

    Khan, G.R.; Kandasami, A.; Bhat, B.A.

    2016-01-01

    Swift Heavy Ion (SHI) irradiation with 200 MeV Ag 9+ -ion beam at ion fluences of 1E11, 5E11, 1E12, and 5E12 for tuning of electrical transport properties of VO 2 thin films fabricated by so–gel technique on alumina substrates has been demonstrated in the present paper. The point defects created by SHI irradiation modulate metal to insulator phase transition temperature, carrier concentration, carrier mobility, electrical conductivity, and Seebeck coefficient of VO 2 thin films. The structural properties of the films were characterized by XRD and Raman spectroscopy and crystallite size was found to decrease upon irradiation. The atomic force microscopy revealed that the surface roughness of specimens first decreased and then increased with increasing fluence. Both resistance as well as Seebeck coefficient measurements demonstrated that all the samples exhibit metal–insulator phase transition and the transition temperatures decreases with increasing fluence. Hall effect measurements exhibited that carrier concentration increased continuously with increasing fluence which resulted in an increase of electrical conductivity by several orders of magnitude in the insulating phase. Seebeck coefficient in insulating phase remained almost constant in spite of an increase in the electrical conductivity by several orders of magnitude making SHI irradiation an alternative stratagem for augmentation of thermoelectric performance of the materials. The carrier mobility at room temperature decreased up to the beam fluence of 5E11 and then started increasing whereas Seebeck coefficient in metallic state first increased with increasing ion beam fluence up to 5E11 and thereafter decreased. Variation of these electrical transport parameters has been explained in detail. - Highlights: • Thermoelectric properties of VO 2 thin films enhance upon SHI irradiation. • Structural properties show that crystallite size decrease upon SHI irradiation. • Metal–insulator phase

  14. QMD simulation of multifragment production in heavy ion collisions at E/A=600 MeV

    International Nuclear Information System (INIS)

    Begemann-Blaich, M.; Mueller, W.F.J.; Aichelin, J.; Hubele, J.; Imme, G.; Leray, S.; Lindenstruth, V.; Liu, Z.; Lynen, U.; Meijer, R.J.; Milkau, U.; Moroni, A.; Ogilvie, C.A.; Pochodzalla, J.; Raciti, G.; Schuettauf, A.; Stuttge, L.; Tucholski, A.

    1993-04-01

    With the ALADIN forward spectrometer the fragmentation of gold nuclei at 600 MeV per nucleon after interaction with carbon, aluminum, copper and lead targets has been investigated. The results are compared to quantum-molecular-dynamics calculations using soft and hard equations of state as well as soft equation of state with momentum dependent forces. Whereas the QMD has been successfully applied to heavy ion collisions at lower energies, it is not possible to reproduce the fragment distributions and the light particle multiplicities observed in this experiment at relativistic energies. To study the reasons for the discrepancy between the experimental data and the simulations, we investigated the time evolution of the nuclear system after a collision and the disintegration pattern of excited nuclei in the QMD approach. (orig.). 9 figs

  15. Coincidence measurements of slow recoil ions with projectile ions in 42-MeV Arq+-Ar collisions

    International Nuclear Information System (INIS)

    Tonuma, T.; Kumagai, H.; Matsuo, T.; Tawara, H.

    1989-01-01

    Slow Ar recoil-ion production cross sections by projectiles of 1.05-MeV/amu Ar q+ (q=4,6,8,10,12,14) were measured using a projectile-ion--recoil-ion coincidence technique. The present results indicate that the average recoil ion charges left-angle i right-angle increase with increasing the incident projectile charge q and the number of the lost and captured electrons from and/or into projectiles, whereas the projectile charge-changing cross sections for loss ionization decrease steeply with increasing q for low-charge-state projectiles, and those for transfer ionization increase rapidly with increasing q for high-charge-state projectiles. For Ar projectiles with q=10, which corresponds to the equilibrium charge state of Ar projectiles at the present collision energy, the average recoil-ion charges are nearly the same in both loss and transfer ionization, and a pure ionization process plays a much more important role in producing highly charged recoil ions, in contrast to projectile electron loss or transfer processes, which play a role in other projectile charge states

  16. Fundamentals and applications of heavy ion collisions below 10 MeV/ nucleon energies

    CERN Document Server

    Prasad, R

    2018-01-01

    An up-to-date text, covering the concept of incomplete fusion (ICF) in heavy ion (HI) interactions at energies below 10 MeV/nucleon. Important concepts including the exciton model, the Harp Miller and Berne model, Hybrid model, Sum rule model, Hot spot model and promptly emitted particles model are covered in depth. It studies the ICF and PE-emission in heavy ion reactions at low energies using off-beam and in-beam experimental techniques. Theories of complete fusion (CF) of heavy ions based on Compound Nucleus (CN) mechanism of statistical nuclear reactions, details of the Computer code PACE4 based on CN mechanism, pre-equilibrium (PE) emission, modeling of (ICF) and their limits of application are discussed in detail.

  17. Using MDECR-PECVD to study the impact of ion bombardment energy on microstructural properties of μc-Si:H thin film grown from an SiF{sub 4}/H{sub 2} chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Junkang; Florea, Ileana; Bulkin, Pavel V.; Maurice, Jean-Luc; Johnson, Erik V. [LPICM, CNRS, Ecole Polytechnique, Universite Paris Saclay, 91128 Palaiseau (France)

    2016-12-15

    The matrix-distributed electron cyclotron resonance plasma-enhanced chemical vapor deposition (MDECR-PECVD) technique has been shown to achieve high deposition rates for hydrogenated microcrystalline silicon (μc-Si:H) thin film. Due to the fact that plasma is sustained by a microwave discharge, by biasing the substrate holder with additional power supply, one can achieve independent control over the plasma density and the maximum ion bombardment energy (IBE). In this work, we present studies of the impact of IBE on the microstructural properties of the μc-Si:H film deposited by MDECR-PECVD. Insufficient ion bombardment is found to be responsible for the substantial presence of nano-porous regions within the material, resulting in significant post-deposition oxidation. Good agreement between transmission electron microscopy (TEM) Fresnel contrast analysis and the results of infrared absorption and hydrogen effusion measurements for the deposited films suggest that moderate IBE is of vital importance to achieve high quality μc-Si:H. In doing so, denser films with significantly decreased nano-porous regions and better stability are obtained, which is of great interest to optimize the process parameters for solar cell applications. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Measurement of omega, the energy required to create an ion pair, for 150-MeV protons in nitrogen and argon

    International Nuclear Information System (INIS)

    Petti, P.L.

    1985-01-01

    The purpose of this thesis is to provide a 1% measurement of omega, the energy required to produce an ion pair, for 150 MeV protons in various gases. Such a measurement should improve the accuracy of proton ionization chamber dosimetry at the Harvard Cyclotron Laboratory. Currently, no measurements of omega exist in the energy range of 30 to 150 MeV, and present ionization chamber dosimetry at the Cyclotron relies on average values of measurements at lower and higher energies (i.e. for E < 3 MeV and E = 340 MeV). Contrary to theoretical expectations, these low and high energy data differ by as much as 9% in some gases. The results of this investigation demonstrate that the existing high energy data is probably in error, and current proton ionization chamber dosimetry underestimates omega, and hence the proton dose, by 5%

  19. Neutron yields from bombardment of α-particles

    International Nuclear Information System (INIS)

    Nakasima, Ryuzo

    1982-09-01

    The thick target neutron yields from bombardment of <10 MeV α-particles are calculated based on the reaction cross sections. The results for the elements of Z < 15 are compared with existing calculated or measured neutron yield data. For the elements of 16 < Z < 50, elemental or isotopic neutron yields are calculated if the cross section data are available. (author)

  20. Effect of 50 and 80 MeV phosphorous ions on the contribution of interface and oxide state density in n-channel MOSFETs

    Energy Technology Data Exchange (ETDEWEB)

    Shinde, N.S.; Dhole, S.D.; Kanjilal, D.; Bhoraskar, V.N. E-mail: vnb@physics.unipune.ernet.in

    1999-07-02

    n-channel depletion MOS devices were irradiated with 50 and 80 MeV phosphorous ions, with different fluences varying in the range from 10{sup 11} to 10{sup 13} ions/cm{sup 2}. The pre and post irradiation I-V characteristics were measured and the corresponding threshold shift {delta}V{sub TH} was estimated. In both the cases, the drain current I{sub D} and the threshold voltage V{sub TH} were found to decrease with the ion fluence. The increase in the threshold voltage shift {delta}V{sub TH} with the ion fluence, was greater for the devices irradiated with 80 MeV ions than those irradiated with 50 MeV ions. The interface and oxide state densities were determined through the subthreshold voltage measurements. To separate the contributions of oxide and interface states towards the threshold voltage shift, the ion irradiated MOS devices were annealed at 150 deg. C. The threshold shift during annealing initially decreased and later increased with increasing annealing period. The rate of change of the interface states during annealing was higher than that of the oxide states. It was also found that depletion mode (normally ON) MOSFETs switched operation to enhancement mode (normally OFF)

  1. Experimental study of the slowing down of heavy ions at 20 to 100 MeV per nucleon in matter

    International Nuclear Information System (INIS)

    Herault, J.

    1988-01-01

    The measurements of typical parameters on heavy ions penetration through matter presented in this work have been performed at the GANIL accelerator facility, using the LISE magnetic spectrometer from 20 to 100 MeV per nucleon. Two magnetic optical configurations of the spectrometer LISE corresponding respectively to energy and angle analysis, have been used. In the first configuration, the analysis of the energy loss distribution, caused by the interaction of the heavy ions beam with the target material, permit to determine the stopping power and the energy straggling. The stopping power is defined experimentally by the ratio of the average energy loss in the target to the thickness of this one. This quantity has been measured for a set of heavy ions ( 17 O, 40 Ar, 86 Kr and 132 Xe) in gaseous media (H 2 , He, N 2 , Ne, Ar, Kr, Xe, CH 4 , C 4 H 10 , CO 2 and CF 4 ) and compared to semi-empirical tabulations. These determinations are compared to those obtained in solid media to study the evolution of the solid-gas difference. This effect vanishes progressively when the projectile tends to be totally stripped (the charge state becomes identical to the atomic number). The heavy ion energy distributions at the exit of degraders and particularly their full width at half maximum have been measured for various projectiles ( 16 O, 40 Ar, 84 Kr, 86 Kr, 100 Mo and 132 Xe) in solid (Be, C, Al, Si, Ti, Ni, Cu, Ag, Ta, Au and Mylar) and gaseous media (the same as for stopping power determinations). A significant contribution of charge exchange straggling to the energy loss straggling is observed for partially stripped ions. A second optical configuration of the beam line LISE has been used, to obtain an image of heavy ions beams passing through targets for various heavy ions ( 16 O, 17 O, 40 Ar, 86 Kr and 100 Mo) in gaseous and solid media. The scaling law for angular straggling is confirmed and extended over five orders of magnitude [fr

  2. 160 MeV Ni12+ ion irradiation effects on the structural, optical and electrical properties of spherical polypyrrole nanoparticles

    International Nuclear Information System (INIS)

    Hazarika, J.; Kumar, A.

    2014-01-01

    Highlights: • Upon SHI irradiation the average diameters of PPy nanoparticles increases. • Crystallinity of PPy nanoparticles increases with increasing ion fluence. • IR active vibrational bands have different cross sections for SHI irradiation. • Upon SHI irradiation optical band gap energy of PPy nanoparticles decreases. • Upon SHI irradiation thermal stability of PPy nanoparticles increases. -- Abstract: In this study we report 160 MeV Ni 12+ swift heavy ion irradiation induced enhancement in the structural, optical and electrical properties of spherical polypyrrole (PPy) nanoparticles. High resolution transmission electron microscope results show that the pristine PPy nanoparticles have an average diameter of 11 nm while upon irradiation the average diameter increases to 18 nm at the highest ion fluence of 1 × 10 12 ions/cm 2 . X-ray diffraction studies show an enhancement of crystallinity and average crystallite size of PPy nanoparticles with increasing fluence. Studies of Fourier transform infrared spectra suggest the structural modifications of different functional groups upon irradiation. It also reveals that different functional groups have different sensitivity to irradiation. The infrared active N–H vibrational band at 3695 cm −1 is more sensitive to irradiation with a formation cross-section of 5.77 × 10 −13 cm 2 and effective radius of 4.28 nm. The UV–visible absorption spectra of PPy nanoparticles show that the absorption band undergoes a red shift with increasing fluence. Moreover upon irradiation the optical band gap energy decreases and Urbach’s energy increases with fluence. Thermo-gravimetric analysis studies suggest that upon irradiation the thermal stability of PPy nanoparticles increases which may be attributed to their enhanced crystallinity. Current–voltage characteristics of PPy nanoparticles exhibit non-Ohmic, symmetric behavior which increases with fluence

  3. Confirmatory experiments for the United States Department of Energy Accelerator Production of Tritium Program: Neutron, triton and radionuclide production by thick targets of lead and tungsten bombarded by 800 MeV protons

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Cappiello, M.; Ullmann, J.L.; Gavron, A.; King, J.D.; Laird, R.; Mayo, D.; Waters, L.; Zoeller, C.; Staples, P.

    1994-01-01

    Neutron and Triton Production by 800 MeV Protons: The experiments presented in this report were performed in support of the Accelerator Production of Tritium (APT) project at the Los Alamos Weapons Neutron Research (WNR) facility in order to provide data to benchmark and validate physics simulations used in the APT target/blanket design. An experimental apparatus was built that incorporated many of the features of the neutron source region of the 3 He target/blanket. Those features included a tungsten neutron source, flux traps, neutron moderator, lead backstop, lead multiplying annulus, neutron absorbing blanket and a combination neutron de-coupler and tritium producing gas ( 3 He). The experiments were performed in two separate proton irradiations each with approximately 100 nA-hr of 800 MeV protons. The first irradiation was made with a small neutron moderating blanket, allowing the authors to measure tritium production in the 3 He gas by sampling, and counting the amount of tritium. The second irradiation was performed with a large neutron moderating blanket (light water with a 1% manganese sulfate solution) that allowed them to measure both the tritium production in the central region and the total neutron production. The authors did this by sampling and counting the tritium produced and by measuring the activation of the manganese solution. Results of the three tritium production measurements show large disagreements with each other and therefore with the values predicted using the LAHET-MCNP code system. The source of the discrepancies may lie with the sampling system or adsorption on the tungsten surfaces. The authors discuss tests that may resolve that issue. The data for the total neutron production measurement is much more consistent. Those results show excellent agreement between calculation and experiment

  4. 160 MeV Ni{sup 12+} ion irradiation effects on the dielectric properties of polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hazarika, J.; Nath, Chandrani [Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, Assam (India); Kumar, A., E-mail: ask@tezu.ernet.in [Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, Assam (India)

    2012-10-01

    We report on the dielectric properties and a.c. conductivity studies of CSA doped polyaniline nanotubes. Nanotubes of 47-100 nm diameter, were synthesized by the self-assembly method and irradiated using Ni{sup 12+} ions of 160 MeV energy with fluences of 1 Multiplication-Sign 10{sup 10}, 5 Multiplication-Sign 10{sup 10}, 1 Multiplication-Sign 10{sup 11} and 3 Multiplication-Sign 10{sup 11} ions/cm{sup 2}. X-ray diffraction studies reveal an increase in the degree of crystallinity and consequently, the extent of order of the nanotubes with increasing fluence, but show a lower degree of crystallinity at higher fluence. The decrease in d-spacing for the (100) reflections with fluence is ascribed to the decrease in the tilt angle of the aligned polymer chains. A significant change was seen after irradiation in dielectric and electrical properties which may be correlated with the increased carrier concentration and structural modifications in the polymer films. The surface conductivity of films increases with increasing fluence, which also decreases at higher fluence. The a.c. conduction mechanism for the nanotubes could be explained in terms of correlated barrier hopping model. The existence of polarons as the major charge carriers in the present nanotube system was confirmed by the low values of polaron binding energy, found to decrease with fluence. The hopping distance increases with fluence indicating that the hopping probability increases with fluence.

  5. MeV ion irradiation effects on the luminescence properties of Si-implanted SiO{sub 2}-thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chulapakorn, T.; Primetzhofer, D. [Uppsala University, Department of Physics and Astronomy, P.O. Box 516, 751 20 Uppsala (Sweden); Sychugov, I.; Suvanam, S.S.; Linnros, J.; Hallen, A. [Royal Institute of Technology (KTH), School of Information and Communication Technology, P.O. Box Electrum 229, 164 40 Kista (Sweden)

    2016-12-15

    The effects of MeV heavy ion irradiation at varying fluence and flux on excess Si, introduced in SiO{sub 2} by keV ion implantation, are investigated by photoluminescence (PL). From the PL peak wavelength (λ) and decay lifetime (τ), two PL sources are distinguished: (i) quasi-direct recombination of excitons of Si-nanoparticles (SiNPs), appearing after thermal annealing (λ > 720 nm, τ ∝ μs), and (ii) fast-decay PL, possibly due to oxide-related defects (λ ∝ 575-690 nm, τ ∝ ns). The fast-decay PL (ii) observed before and after ion irradiation is induced by ion implantation. It is found that this fast-decay luminescence decreases for higher irradiation fluence of MeV heavy ions. After thermal annealing (forming SiNPs), the SiNP PL is reduced for samples irradiated by MeV heavy ions but found to stabilize at higher level for higher irradiation flux; the (ii) band vanishes as a result of annealing. The results are discussed in terms of the influence of electronic and nuclear stopping powers. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Damage accumulation in MgO irradiated with MeV Au ions at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bachiller-Perea, Diana, E-mail: dianabachillerperea@gmail.com [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, 28049, Madrid (Spain); Dpto. de Física Aplicada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049, Madrid (Spain); Debelle, Aurélien, E-mail: aurelien.debelle@u-psud.fr [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Thomé, Lionel [Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Univ. Paris-Sud, CNRS-IN2P3, Université Paris-Saclay, 91405, Orsay Cedex (France); Behar, Moni [Instituto de Física, Universidade Federal do Rio Grande do Sul, C.P. 15051, 91501-970, Porto Alegre, RS (Brazil)

    2016-09-15

    The damage accumulation process in MgO single crystals under medium-energy heavy ion irradiation (1.2 MeV Au) at fluences up to 4 × 10{sup 14} cm{sup −2} has been studied at three different temperatures: 573, 773, and 1073 K. Disorder depth profiles have been determined through the use of the Rutherford backscattering spectrometry in channeling configuration (RBS/C). The analysis of the RBS/C data reveals two steps in the MgO damage process, irrespective of the temperature. However, we find that for increasing irradiation temperature, the damage level decreases and the fluence at which the second step takes place increases. A shift of the damage peak at increasing fluence is observed for the three temperatures, although the position of the peak depends on the temperature. These results can be explained by an enhanced defect mobility which facilitates defect migration and may favor defect annealing. X-ray diffraction reciprocal space maps confirm the results obtained with the RBS/C technique. - Highlights: • High-temperature MeV-ion irradiated MgO exhibits a two-step damage process. • The occurrence of the second step is delayed with increasing temperature. • The damage level decreases with increasing temperature. • A shift of the damage peak is observed with increasing fluence. • A high defect mobility at high temperatures in MgO is clearly evidenced.

  7. The new generations of power components will depend on neutron and/or electron bombardment techniques

    International Nuclear Information System (INIS)

    Lilen, H.

    1976-01-01

    Neutron and electron bombardment techniques for materials doping, newly introduced in the fabrication of power semiconductor components: diodes, transistors, thyristors, and triacs are briefly outlined. A neutron bombardment of high purity silicon results in a short-lived 31 Si isotope (from 30 Si) decaying into 31 P. The phosphorus with its five peripheral electrons induces a negative doping (N), and the neutron technique gives a homogeneous doping. Furthermore, silicon bombardment with 1 to 2MeV electrons induces micro-ruptures in the lattice, that act as recombination traps reducing carrier lifetimes. Consequently, gold diffusion techniques can be replaced by electron bombardment with a gain in controlling carrier lifetimes [fr

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

    Energy Technology Data Exchange (ETDEWEB)

    Prakrajang, K. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Faculty of Science, Maejo University, Chiang Mai 50290 (Thailand); Jeynes, J.C.G.; Merchant, M.J.; Kirkby, K.; Kirkby, N. [Surrey Ion Beam Center, Faculty of Engineering and Physical Science, University of Surrey, Guildford Surrey, GU2 7XH (United Kingdom); Thopan, P. [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Yu, L.D., E-mail: yuld@fnrf.science.cmu.ac.th [Plasma and Beam Physics Research Facility, Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thailand Center of Excellence in Physics, Commission on Higher Education, 328 Si Ayutthaya Road, Bangkok 10400 (Thailand)

    2013-07-15

    Highlights: •Recently completed nanobeam at the Surrey Ion Beam Centre was used. •3.8-MeV single and broad proton beams irradiated Chinese hamster cells. •Cell survival curves were measured and compared with 300-kV X-ray irradiation. •Single ion irradiation had a lower survival part at ultra-low dose. •It implies hypersensitivity, bystander effect and cell cycle phase of cell death. -- Abstract: 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.

  9. Angle-resolved imaging of single-crystal materials with MeV helium ions

    Energy Technology Data Exchange (ETDEWEB)

    Strathman, M D; Baumann, S [Charles Evans and Associates, Redwood City, CA (United States)

    1992-02-01

    The simplest form of angle-resolved mapping for single-crystal materials is the creation of a channeling angular scan. Several laboratories have expanded this simple procedure to include mapping as a function of two independent tilts. These angle-resolved images are particularly suited to the assessment of crystal parameters including disorder, lattice location of impurities, and lattice stress. This paper will describe the use of the Charles Evans and Associates RBS-400 scattering chamber for acquisition, display, and analysis of angle-resolved images obtained from backscattered helium ions. Typical data acquisition times are 20 min for a {+-}2deg X-Y tilt scan with 2500 pixels (8/100deg resolution), and 10 nC per pixel. In addition, we will present a method for automatically aligning crystals for channeling measurements based on this imaging technology. (orig.).

  10. Energy loss and straggling of MeV Si ions in gases

    Energy Technology Data Exchange (ETDEWEB)

    Vockenhuber, C., E-mail: vockenhuber@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Arstila, K. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Jensen, J. [Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping (Sweden); Julin, J.; Kettunen, H.; Laitinen, M.; Rossi, M.; Sajavaara, T. [Department of Physics, University of Jyväskylä, 40014 Jyväskylä (Finland); Thöni, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Whitlow, H.J. [Institut des Microtechnologies Appliquées Arc, Haute Ecole Arc Ingénierie, 2300 La Chaux-de-Fonds (Switzerland)

    2017-01-15

    We present measurements of energy loss and straggling of Si ions in gases. An energy range from 0.5 to 12 MeV/u was covered using the 6 MV EN tandem accelerator at ETH Zurich, Switzerland, and the K130 cyclotron accelerator facility at the University of Jyväskylä, Finland. Our energy-loss data compare well with calculation based on the SRIM and PASS code. The new straggling measurements support a pronounced peak in He gas at around 4 MeV/u predicted by recent theoretical calculations. The straggling curve structure in the other gases (N{sub 2}, Ne, Ar, Kr) is relatively flat in the covered energy range. Although there is a general agreement between the straggling data and the theoretical calculations, the experimental uncertainties are too large to confirm or exclude the predicted weak multi-peak structure in the energy-loss straggling.

  11. Angle-resolved imaging of single-crystal materials with MeV helium ions

    International Nuclear Information System (INIS)

    Strathman, M.D.; Baumann, S.

    1992-01-01

    The simplest form of angle-resolved mapping for single-crystal materials is the creation of a channeling angular scan. Several laboratories have expanded this simple procedure to include mapping as a function of two independent tilts. These angle-resolved images are particularly suited to the assessment of crystal parameters including disorder, lattice location of impurities, and lattice stress. This paper will describe the use of the Charles Evans and Associates RBS-400 scattering chamber for acquisition, display, and analysis of angle-resolved images obtained from backscattered helium ions. Typical data acquisition times are 20 min for a ±2deg X-Y tilt scan with 2500 pixels (8/100deg resolution), and 10 nC per pixel. In addition, we will present a method for automatically aligning crystals for channeling measurements based on this imaging technology. (orig.)

  12. Ion Beam Materials Analysis and Modifications at keV to MeV Energies at the University of North Texas

    Science.gov (United States)

    Rout, Bibhudutta; Dhoubhadel, Mangal S.; Poudel, Prakash R.; Kummari, Venkata C.; Lakshantha, Wickramaarachchige J.; Manuel, Jack E.; Bohara, Gyanendra; Szilasi, Szabolcs Z.; Glass, Gary A.; McDaniel, Floyd D.

    2014-02-01

    The University of North Texas (UNT) Ion Beam Modification and Analysis Laboratory (IBMAL) has four particle accelerators including a National Electrostatics Corporation (NEC) 9SDH-2 3 MV tandem Pelletron, a NEC 9SH 3 MV single-ended Pelletron, and a 200 kV Cockcroft-Walton. A fourth HVEC AK 2.5 MV Van de Graaff accelerator is presently being refurbished as an educational training facility. These accelerators can produce and accelerate almost any ion in the periodic table at energies from a few keV to tens of MeV. They are used to modify materials by ion implantation and to analyze materials by numerous atomic and nuclear physics techniques. The NEC 9SH accelerator was recently installed in the IBMAL and subsequently upgraded with the addition of a capacitive-liner and terminal potential stabilization system to reduce ion energy spread and therefore improve spatial resolution of the probing ion beam to hundreds of nanometers. Research involves materials modification and synthesis by ion implantation for photonic, electronic, and magnetic applications, micro-fabrication by high energy (MeV) ion beam lithography, microanalysis of biomedical and semiconductor materials, development of highenergy ion nanoprobe focusing systems, and educational and outreach activities. An overview of the IBMAL facilities and some of the current research projects are discussed.

  13. Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag{sup 8+})

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Dhillon, Anju [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Avasthi, D.K. [Inter University Accelerator Center (IUAC), Aruna Asaf Ali Road, New Delhi 110067 (India)

    2013-07-15

    Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10{sup 10} to 10{sup 12} ions cm{sup −2} of 100 MeV silver (Ag{sup 8+}) ions. The temperature dependence of ac conductivity [σ{sub m}(ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag{sup 8+}) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation.

  14. Low frequency alternating current conduction and dielectric relaxation in polypyrrole irradiated with 100 MeV swift heavy ions of silver (Ag8+)

    International Nuclear Information System (INIS)

    Kaur, Amarjeet; Dhillon, Anju; Avasthi, D.K.

    2013-01-01

    Polypyrrole (PPY) films were prepared by electrochemical polymerization technique. The fully undoped samples were irradiated with different radiation fluences ranging from 10 10 to 10 12 ions cm −2 of 100 MeV silver (Ag 8+ ) ions. The temperature dependence of ac conductivity [σ m (ω)], dielectric constant (ε′) and dielectric loss (ε′′) of both irradiated as well as unirradiated samples have been investigated in 77–300 K. There exists typical Debye type dispersion. Giant increase in dielectric constant has been observed for irradiated samples which is attributed to polaronic defects produced during irradiation. - Graphical abstract: Display Omitted - Highlights: • Polypyrrole samples were prepared by electrochemical technique. • The fully undoped samples were irradiated with 100 MeV silver (Ag 8+ ) ions. • Giant increase in dielectric constant in irradiated samples is observed. • Dielectric behaviour is attributed to polaronic defects produced during irradiation

  15. Study on the desorption yield for natural botanic sample induced by energetic heavy ions

    CERN Document Server

    Xue, J M; Du, G H; Yan, S; Zhao, W J

    2002-01-01

    The dependence of desorption yield for the natural botanic sample bombarded with heavy ion on the electronic stopping power (S sub e) and dose has been measured by weighing sample mass before and after irradiation. Primary ions including 50 keV N sup + , 1.5 MeV F sup + , 3.0 MeV F sup 2 sup + , 4.0 MeV F sup 2 sup + and 3.0 MeV Si sup 2 sup + were used in the experiment. Three megaelectron volts of F sup 2 sup + with doses ranging from 4x10 sup 1 sup 5 to 4x10 sup 1 sup 6 ions/cm sup 2 were used in order to investigate the influence of ion dose. A mass spectrum from the sample bombarded with 3 MeV Si sup 2 sup + was also taken for a better understanding of the desorption process. Results show that the natural botanic sample is very easily to be desorpted. The yield of MeV heavy ions can be as high as thousands CH sub 2 O/ion, and significantly depends on both the S sub e and dose. The measured yields increase quickly with S sub e , but drop down with increasing ion dose. These results fit roughly with the pr...

  16. Study on the desorption yield for natural botanic sample induced by energetic heavy ions

    International Nuclear Information System (INIS)

    Xue, J.M.; Wang, Y.G.; Du, G.H.; Yan, S.; Zhao, W.J.

    2002-01-01

    The dependence of desorption yield for the natural botanic sample bombarded with heavy ion on the electronic stopping power (S e ) and dose has been measured by weighing sample mass before and after irradiation. Primary ions including 50 keV N + , 1.5 MeV F + , 3.0 MeV F 2+ , 4.0 MeV F 2+ and 3.0 MeV Si 2+ were used in the experiment. Three megaelectron volts of F 2+ with doses ranging from 4x10 15 to 4x10 16 ions/cm 2 were used in order to investigate the influence of ion dose. A mass spectrum from the sample bombarded with 3 MeV Si 2+ was also taken for a better understanding of the desorption process. Results show that the natural botanic sample is very easily to be desorpted. The yield of MeV heavy ions can be as high as thousands CH 2 O/ion, and significantly depends on both the S e and dose. The measured yields increase quickly with S e , but drop down with increasing ion dose. These results fit roughly with the prediction of the pressure pulse model

  17. Elastic atomic displacements and color center creation in LiF crystals irradiated with 3-, 9- and 12-MeV Au ions

    International Nuclear Information System (INIS)

    Sorokin, M.V.; Papaleo, R.M.; Schwartz, K.

    2009-01-01

    Creation of color centers in LiF under irradiation with 3-12-MeV Au ions was studied. Comparison of experimental data of color center creation with computer simulation of the energy deposition and elastic atomic displacements reveals the role of elastic collisions in defect creation by these ions, which have comparable magnitudes of electronic and elastic stopping. The experimentally measured efficiency of color center creation and that predicted by the simulation of elastic displacements have a similar dependence on the projectile energy. Thus, the color center creation is mainly associated with the elastic collisions, despite the relatively large values of the electronic stopping power for these ions. (orig.)

  18. A Monte Carlo computer code for evaluating energy loss of 10 keV to 10 MeV ions in amorphous silicon materials

    International Nuclear Information System (INIS)

    Erramli, H.; Elbounagui, O.; Misdaq, M.A.; Merzouki, A.

    2007-01-01

    The basic concepts of a computer simulation code for determining the energy loss of ions in the 10 keV to 10 MeV energy range in amorphous silicon materials were presented and discussed. Data obtained were found in good agreement with those obtained by using a SRIM programme. Electronic and nuclear energy losses were evaluated. Variation of the energy loss as a function of the incident ion energy were studied. This new computer code is a good tool for evaluating stopping powers of various materials for light and heavy ions

  19. Peripheral heavy-ion induced reactions at intermediate energies 20MeVMeV

    International Nuclear Information System (INIS)

    Barrette, J.; Berthier, B.; Chavez, E.

    1984-03-01

    Inclusive energy spectra and angular distributions of projectile like fragments in reactions induced by a 44 MeV/nucleon 40 Ar beam bombarding 27 Al and sup(nat)Ti targets show many of the features of high energy fragmentation. However, several aspects such as energy dissipation and production of fragments heavier than the projectile are reminiscent of a low energy behaviour

  20. Correlation between the structure modification and conductivity of 3 MeV Si ion-irradiated polyimide

    International Nuclear Information System (INIS)

    Sun Youmei; Zhu Zhiyong; Li Changlin

    2002-01-01

    The surface modification of the polyimide (PI/Kapton) films was carried out by 3 MeV Si + implantation to fluences ranging from 1x10 12 to 1.25x10 15 ions/cm 2 . Fourier transform infrared (FTIR), Raman and ultraviolet/visible (UV/Vis) spectroscopes were employed to investigate the chemical degradation of function groups in the irradiated layer. FTIR results show that the absorbance of typical function group decreases exponentially as a function of fluence. The damage cross-section of typical bonds of PI was evaluated from the FTIR spectra. Raman analysis shows the absorbed dose for destruction of all function groups is above 218 MGy. The red shifting of the absorption edge from UV to visible reveals the band gap closing which results from increase of the cluster size. The production efficiency of the chromophores was discussed according to UV/Vis analysis. Irradiation dramatically enhances the electrical conductivity and the sheet resistivity in our experiment descends nearly 10 orders of magnitude compared with its intrinsic value

  1. Anomalous heat evolution of deuteron implanted Al on electron bombardment

    International Nuclear Information System (INIS)

    Kamada, K.; Kinoshita, H.; Takahashi, H.

    1994-05-01

    Anomalous heat evolution was observed in deuteron implanted Al foils on 175 keV electron bombardment. Local regions with linear dimension of several 100nm showed simultaneous transformation from single crystalline to polycrystalline structure instantaneously on the electron bombardment, indicating the temperature rise up to more than melting point of Al from room temperature. The amount of energy evolved was more than 180 MeV for each transformed region. The transformation was never observed in proton implanted Al foils. The heat evolution was considered due to a nuclear reaction in D 2 molecular collections. (author)

  2. Use of radial self-field geometry for intense pulsed ion beam generation above 6 MeV on Hermes III.

    Energy Technology Data Exchange (ETDEWEB)

    Renk, Timothy Jerome [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Harper-Slaboszewicz, Victor Jozef [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ginn, William Craig [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mikkelson, Kenneth A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schall, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Gary Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-12-01

    We investigate the generation and propagation of intense pulsed ion beams at the 6 MeV level and above using the Hermes III facility at Sandia National Laboratories. While high-power ion beams have previously been produced using Hermes III, we have conducted systematic studies of several ion diode geometries for the purpose of maximizing focused ion energy for a number of applications. A self-field axial-gap diode of the pinch reflex type and operated in positive polarity yielded beam power below predicted levels. This is ascribed both to power flow losses of unknown origin upstream of the diode load in Hermes positive polarity operation, and to anomalies in beam focusing in this configuration. A change to a radial self-field geometry and negative polarity operation resulted in greatly increased beam voltage (> 6 MeV) and estimated ion current. A comprehensive diagnostic set was developed to characterize beam performance, including both time-dependent and time-integrated measurements of local and total beam power. A substantial high-energy ion population was identified propagating in reverse direction, i.e. from the back side of the anode in the electron beam dump. While significant progress was made in increasing beam power, further improvements in assessing the beam focusing envelope will be required before ultimate ion generation efficiency with this geometry can be completely determined.

  3. Ionic conduction in 70-MeV C5+-ion-irradiated poly(vinylidenefluoride- co-hexafluoropropylene)-based gel polymer electrolytes

    International Nuclear Information System (INIS)

    Saikia, D.; Kumar, A.; Singh, F.; Avasthi, D.K.; Mishra, N.C.

    2005-01-01

    In an attempt to increase the Li + -ion diffusivity, poly(vinylidenefluoride-co-hexafluoropropylene)-(propylene carbonate+diethyl carbonate)-lithium perchlorate gel polymer electrolyte system has been irradiated with 70-MeV C 5+ -ion beam of nine different fluences. Swift heavy-ion irradiation shows enhancement in ionic conductivity at lower fluences and decrease in ionic conductivity at higher fluences with respect to unirradiated gel polymer electrolyte films. Maximum room-temperature (303 K) ionic conductivity is found to be 2x10 -2 S/cm after irradiation with a fluence of 10 11 ions/cm 2 . This interesting result could be attributed to the fact that for a particular ion beam with a given energy, a higher fluence provides critical activation energy for cross linking and crystallization to occur, which results in the decrease in ionic conductivity. X-ray-diffraction results show decrease in the degree of crystallinity upon ion irradiation at low fluences (≤10 11 ions/cm 2 ) and increase in crystallinity at higher fluences (>10 11 ions/cm 2 ). Analysis of Fourier-transform infrared spectroscopy results suggests the bond breaking at a fluence of 5x10 9 ions/cm 2 and cross linking at a fluence of 10 12 ions/cm 2 and corroborate conductivity and x-ray-diffraction results. Scanning electron micrographs exhibit increased porosity of the polymer electrolyte after ion irradiation

  4. Effect of 100 MeV Ag{sup +7} ion irradiation on the bulk and surface magnetic properties of Co–Fe–Si thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hysen, T., E-mail: hysenthomas@gmail.com [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Department of Physics, Christian College, Chengannur, Kerala 689 122 (India); Geetha, P. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Al-Harthi, Salim; Al-Omari, I.A. [Department of Physics, College of Science, Sultan Qaboos University, Al Khod 123 (Oman); Lisha, R. [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India); Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639 798 (Singapore); Sakthikumar, D. [Graduate School of Interdisciplinary New Science, Toyo University, Kawagoe (Japan); Avasthi, D.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Anantharaman, M.R., E-mail: mra@cusat.ac.in [Department of Physics, Cochin University of Science and Technology, Cochin 682 022, Kerala (India)

    2014-12-15

    Thin films of Co–Fe–Si were vacuum evaporated on pre-cleaned float glass substrates employing thermal evaporation. The films were subsequently irradiated with 100 MeV Ag{sup +7} ions at fluences of 1×10{sup 11}, 1×10{sup 12} and 1×10{sup 13} ions/cm{sup 2}. The pristine and irradiated samples were subjected to surface analysis using Atomic Force Microscopy (AFM), Vibrating Sample Magnetometry (VSM) and Magneto Optic Kerr Effect (MOKE) measurements. The as deposited film has a root mean square roughness (Rq) of 8.9 nm and an average roughness of (Ra) 5.6 nm. Irradiation of the as deposited films with 100 MeV Ag{sup 7+} ions modifies the surface morphology. Irradiating with ions at fluences of 1×10{sup 11} ions/cm{sup 2} smoothens the mesoscopic hill-like structures, and then, at 1×10{sup 12} ions/cm{sup 2} new surface structures are created. When the fluence is further increased to 1×10{sup 13} ions/cm{sup 2} an increase in the surface roughness is observed. The MOKE loop of as prepared film indicated a squareness ratio of 0.62. As the film is irradiated with fluences of 1×10{sup 11} ions/cm{sup 2}, 1×10{sup 12} ions/cm{sup 2} and 1×10{sup 13} ions/cm{sup 2} the squareness ratio changes to 0.76, 0.8 and 0.86 respectively. This enhancement in squareness ratio towards 1 is a typical feature when the exchange interaction starts to dominates the inherent anisotropies in the system. The variation in surface magnetisation is explained based on the variations in surface roughness with swift heavy ion (SHI) irradiation. - Highlights: • We have irradiated thermally evaporated Co–Fe–Si thin films on glass substrate with 100 MeV Ag{sup +7} ions using the 15 UD Pelletron Accelerator at IUAC, New Delhi, India. • Surface morphology and magnetic characteristics of the films can be altered with ion irradiation. • It was observed that the variation in surface magnetic properties correlates well with the changes in surface morphology, further reiterating the

  5. Thermal spike model interpretation of sputtering yield data for Bi thin films irradiated by MeV {sup 84}Kr{sup 15+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Mammeri, S. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Ouichaoui, S., E-mail: souichaoui@gmail.com [Université des Sciences et de la Technologie H. Boumediene (USTHB), Faculté de Physique, Laboratoire SNIRM, B.P. 32, El-Alia, 16111 Bab Ezzouar, Algiers (Algeria); Ammi, H. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Pineda-Vargas, C.A. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, CPUT, P.O. Box 1906, Bellville 7535 (South Africa); Dib, A. [Centre de Recherche Nucléaire d’Alger, B.P. 399, 02 Bd. Frantz Fanon, Alger-gare, Algiers (Algeria); Msimanga, M. [iThemba LABS, National Research Foundation, P. Bag 11, Wits 2050, Johannesburg (South Africa); Department of Physics, Tshwane University of Technology, P. Bag X680, Pretoria 001 (South Africa)

    2015-07-01

    A modified thermal spike model initially proposed to account for defect formation in metals within the high heavy ion energy regime is adapted for describing the sputtering of Bi thin films under MeV Kr ions. Surface temperature profiles for both the electronic and atomic subsystems have been carefully evaluated versus the radial distance and time with introducing appropriate values of the Bi target electronic stopping power for multi-charged Kr{sup 15+} heavy ions as well as different target physical proprieties like specific heats and thermal conductivities. Then, the total sputtering yields of the irradiated Bi thin films have been determined from a spatiotemporal integration of the local atomic evaporation rate. Besides, an expected non negligible contribution of elastic nuclear collisions to the Bi target sputtering yields and ion-induced surface effects has also been considered in our calculation. Finally, the latter thermal spike model allowed us to derive numerical sputtering yields in satisfactorily agreement with existing experimental data both over the low and high heavy ion energy regions, respectively, dominated by elastic nuclear collisions and inelastic electronic collisions, in particular with our data taken recently for Bi thin films irradiated by 27.5 MeV Kr{sup 15+} heavy ions. An overall consistency of our model calculation with the predictions of sputtering yield theoretical models within the target nuclear stopping power regime was also pointed out.

  6. CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

    Science.gov (United States)

    Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

    2015-08-01

    Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

  7. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

    International Nuclear Information System (INIS)

    Jeong, Tae Won; Ter-Avetisyan, S.; Singh, P. K.; Kakolee, K. F.; Scullion, C.; Ahmed, H.; Hadjisolomou, P.; Alejo, A.; Kar, S.; Borghesi, M.

    2016-01-01

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles’ impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5–58 MeV carbon ions and for protons in the energy range 2–17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

  8. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

    Science.gov (United States)

    Jeong, Tae Won; Singh, P. K.; Scullion, C.; Ahmed, H.; Kakolee, K. F.; Hadjisolomou, P.; Alejo, A.; Kar, S.; Borghesi, M.; Ter-Avetisyan, S.

    2016-08-01

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles' impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5-58 MeV carbon ions and for protons in the energy range 2-17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

  9. Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Tae Won; Ter-Avetisyan, S. [Center for Relativistic Laser Science, Institute of Basic Science (IBS), Gwangju 61005 (Korea, Republic of); Department of Physics and Photon Science, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Singh, P. K.; Kakolee, K. F. [Center for Relativistic Laser Science, Institute of Basic Science (IBS), Gwangju 61005 (Korea, Republic of); Scullion, C.; Ahmed, H.; Hadjisolomou, P.; Alejo, A.; Kar, S.; Borghesi, M. [School of Mathematics and Physics, The Queen’s University of Belfast, Belfast BT7 1NN (United Kingdom)

    2016-08-15

    The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles’ impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5–58 MeV carbon ions and for protons in the energy range 2–17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energies E ≳ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

  10. Anomalous behavior in temporal evolution of ripple wavelength under medium energy Ar{sup +}-ion bombardment on Si: A case of initial wavelength selection

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Sandeep Kumar [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Cuerno, Rodolfo [Departamento de Matematicas and Grupo Interdisciplinar de Sistemas Complejos (GISC), Universidad Carlos III de Madrid, 28911 Leganes (Spain); Kanjilal, Dinakar [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Som, Tapobrata, E-mail: tsom@iopb.res.in [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

    2016-06-14

    We have studied the early stage dynamics of ripple patterns on Si surfaces, in the fluence range of 1–3 × 10{sup 18} ions cm{sup −2}, as induced by medium energy Ar{sup +}-ion irradiation at room temperature. Under our experimental conditions, the ripple evolution is found to be in the linear regime, while a clear decreasing trend in the ripple wavelength is observed up to a certain time (fluence). Numerical simulations of a continuum model of ion-sputtered surfaces suggest that this anomalous behavior is due to the relaxation of the surface features of the experimental pristine surface during the initial stage of pattern formation. The observation of this hitherto unobserved behavior of the ripple wavelength seems to have been enabled by the use of medium energy ions, where the ripple wavelengths are found to be order(s) of magnitude larger than those at lower ion energies.

  11. Steady State Sputtering Yields and Surface Compositions of Depleted Uranium and Uranium Carbide bombarded by 30 keV Gallium or 16 keV Cesium Ions.

    Energy Technology Data Exchange (ETDEWEB)

    Siekhaus, W. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Teslich, N. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weber, P. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-10-23

    Depleted uranium that included carbide inclusions was sputtered with 30-keV gallium ions or 16-kev cesium ions to depths much greater than the ions’ range, i.e. using steady-state sputtering. The recession of both the uranium’s and uranium carbide’s surfaces and the ion corresponding fluences were used to determine the steady-state target sputtering yields of both uranium and uranium carbide, i.e. 6.3 atoms of uranium and 2.4 units of uranium carbide eroded per gallium ion, and 9.9 uranium atoms and 3.65 units of uranium carbide eroded by cesium ions. The steady state surface composition resulting from the simultaneous gallium or cesium implantation and sputter-erosion of uranium and uranium carbide were calculated to be U₈₆Ga₁₄, (UC)₇₀Ga₃₀ and U₈₁Cs₉, (UC)₇₉Cs₂₁, respectively.

  12. Investigation of the channeling of light ions through gold crystals having thicknesses of several hundreds of angstroms from 0.5 to 2 MeV

    International Nuclear Information System (INIS)

    Poizat, J.C.; Remillieux, J.

    A technique to obtain a few hundred A thick self-supporting gold crystal is described. These crystals have been used to perform three channeling experiments with 0.5 to 2 MeV light ions: i) The wide angle scattering probability as a function of the distance from the crystal surface was studied for a beam of particles incident in planar and axial directions. ii) The influence of channeling on the light emission from crystal-excited atomic beams was investigated. iii) A strong channeling effect was found on the probability of transmission of a molecular beam of H 2 + ions through a thin crystal

  13. Ion tail formation and its effect on 14-MeV neutron generation in D-3He plasmas

    International Nuclear Information System (INIS)

    Matsuura, H.; Nakao, Y.; Kudo, K.

    1992-01-01

    This paper reports on the triton distribution function in D- 3 He plasmas which is distorted from a Maxwellian owing to the presence of a 1.01-MeV birth component. The deuteron-triton reaction rate (i.e., 14-MeV neutron generation rate) in the plasma should be smaller than the values evaluated by assuming a Maxwellian triton distribution. A local Fokker-Planck calculation shows that although the degree of the decrease in 14-MeV neutron generation strongly depends on the plasma conditions and also on the energy loss mechanism, it becomes appreciable in actual burning plasmas

  14. Modification of the microstructure and electronic properties of rutile TiO_2 thin films with 79 MeV Br ion irradiation

    International Nuclear Information System (INIS)

    Rath, Haripriya; Dash, P.; Singh, U.P.; Avasthi, D.K.; Kanjilal, D.; Mishra, N.C.

    2015-01-01

    Modifications induced by 79 MeV Br ions in rutile titanium dioxide thin films, synthesized by dc magnetron sputtering are presented. Irradiations did not induce any new XRD peak corresponding to any other phase. The area and the width of the XRD peaks were considerably affected by irradiation, and peaks shifted to lower angles. But the samples retained their crystallinity at the highest fluence (1 × 10"1"3 ions cm"−"2) of irradiation even though the electronic energy loss of 79 MeV Br ions far exceeds the reported threshold value for amorphization of rutile TiO_2. Fitting of the fluence dependence of the XRD peak area to Poisson equation yielded the radius of ion tracks as 2.4 nm. Ion track radius obtained from the simulation based on the thermal spike model matches closely with that obtained from the fluence dependence of the area under XRD peaks. Williamson–Hall analysis of the XRD spectra indicated broadening and shifting of the peaks are a consequence of irradiation induced defect accumulation leading to microstrains, as was also indicated by Raman and UV–Visible absorption study.

  15. Formation of slab waveguides in eulytine type BGO and CaF{sub 2} crystals by implantation of MeV nitrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Banyasz, I., E-mail: bakonyjako@yahoo.es [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Berneschi, S. [Centro Studi e Ricerche ' Enrico Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); MDF-Lab, ' ' Nello Carrara' ' Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Khanh, N.Q.; Lohner, T. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Lengyel, K. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Fried, M. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Peter, A. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Petrik, P.; Zolnai, Z. [Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Watterich, A. [Department of Crystal Physics, Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Nunzi-Conti, G.; Pelli, S.; Righini, G.C. [MDF-Lab, ' ' Nello Carrara' ' Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2012-09-01

    Ion implantation, compared with other waveguide fabrication methods, has some unique advantages. It has proved to be a universal technique for producing waveguides in most optical materials. The authors of the present article reported fabrication of channel and slab waveguides in an Erbium-doped tungsten tellurite glass by implantation of MeV energy N{sup +} ions. The present article reports successful adaptation of the same technique to the fabrication of slab waveguides in eulytine type bismuth germanate (BGO) and CaF{sub 2} crystals. This is the first report on successful waveguide fabrication in these materials using 3.5 MeV N{sup +} ions at implanted fluences between 5 Multiplication-Sign 10{sup 15} and 4 Multiplication-Sign 10{sup 16} ions/cm{sup 2}. Spectroscopic ellipsometric measurements revealed the existence of guiding structures in both materials. M-line spectroscopic measurements indicated guiding effect in the as-implanted BGO up to 1550 nm and up to 980 nm in the as-implanted CaF{sub 2}. Ion implantation induced the appearance of three peaks in the UV/Vis absorption spectrum of CaF{sub 2}, that can be attributed to colour centres.

  16. Multiple scattering of MeV ions: Comparison between the analytical theory and Monte-Carlo and molecular dynamics simulations

    International Nuclear Information System (INIS)

    Mayer, M.; Arstila, K.; Nordlund, K.; Edelmann, E.; Keinonen, J.

    2006-01-01

    Angular and energy distributions due to multiple small angle scattering were calculated with different models, namely from the analytical Szilagyi theory, the Monte-Carlo code MCERD in binary collision approximation and the molecular dynamics code MDRANGE, for 2 MeV 4 He in Au at backscattering geometry and for 20 MeV 127 I recoil analysis of carbon. The widths and detailed shapes of the distributions are compared, and reasons for deviations between the different models are discussed

  17. Energy dependence of Lα-to-Ll x-ray intensity ratios for Yb and Pb produced by heavy-ion bombardment

    International Nuclear Information System (INIS)

    Gray, T.J.

    1980-01-01

    Measurements of the incident-ion energy dependence of Lα-to-Ll x-ray intensity ratios are reported for protons incident at 0.40 to 2.20 MeV/amu on thin targets of Pb and for 4 He and C ions incident upon Yb. The data are compared to calculations of the Lα-to-Ll ratio which include the effects of alignment of the 2p/sub 3/2/ state of the target

  18. Measurement of the total reaction cross section for interactions between heavy ions (application to the system 12C+12C at 112MeV)

    International Nuclear Information System (INIS)

    Cherkaoui-Tadili, R.

    1982-01-01

    The total reaction cross-section σsub(R) for interactions between heavy ions is predicted to decrease rapidly with the energy of the incident projectile over the energy range 10 MeV/A - 100 MeV/A. We present here an experimental met σsub(R) to test the model based predictions. The method consists in counting the number of all incoming projectiles and the number of out going projectiles that did not interact with the target. The difference between these two numbers corresponds to the number of particles that reacted with the target nuclei and is therefore proportional to σsub(R). Values of σsub(R) have been measured for the system 12 C + 12 C at two incident energies of 112 MeV and 996 MeV. The results of 1444 +- 70 (112 MeV) and 994 +- 50 (996 MeV) show a total reaction cross-section decreasing with energy as predicted from the Glauber model and optical model fits to elastic scattering [fr

  19. Thermoluminescence properties of Al{sub 2}O{sub 3}:Tb nanoparticles irradiated by gamma rays and 85 MeV C{sup 6+} ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Salah, Numan, E-mail: nsalah@kau.edu.sa [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Alharbi, Najlaa D. [Sciences Faculty for Girls, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Habib, Sami S. [Center of Nanotechnology, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Lochab, S.P. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2015-11-15

    Carbon ions beam is recently recognized as an ideal cancer treatment modality, because of its excellent local tumor control. These ions have a high relative biological effectiveness resulting from high linear energy transfer (LET) and their sharp Bragg peak. However, the dose of those energetic ions needs to be measured with great precision using a proper dosimeter. Aluminum Oxide (Al{sub 2}O{sub 3}) is a highly luminescent phosphor widely used for radiation dosimetry using thermoluminesence (TL) technique. In this work nanoparticles of this material activated by different elements like Eu, Tb, Dy, Cu and Ag were evaluated for their TL response to gamma rays irradiation. Tb doped sample is found to be the most sensitive sample, which could be selected for exposure to 85 MeV C{sup 6+} ion beam in the fluence range 10{sup 9}–10{sup 13} ions/cm{sup 2}. The obtained result shows that C ion beam irradiated sample has a simple glow curve structure with a prominent glow peak at around 230 °C. This glow curve has a dosimetric peak better than those induced by gamma rays. This glow peak exhibits a linear response in the range 10{sup 9}–10{sup 11} ions/cm{sup 2}, corresponding to the equivalent absorbed doses 0.285–28.5 kGy. The absorbed doses, penetration depths and main energy loss were calculated using TRIM code based on the Monte Carlo simulation. The wide linear response of Al{sub 2}O{sub 3}:Tb nanoparticles along with the low fading makes this low cost nanomaterial a good candidate for C ion beam dosimetry. - Highlights: • Nanoparticles of Al{sub 2}O{sub 3} doped with Eu, Tb, Dy, Cu and Ag were synthesised. • They were evaluated for their TL response to gamma rays and C ion beam irradiation. • Tb doped sample is the most sensitive sample to gamma rays. • Al{sub 2}O{sub 3}:Tb was exposed to 85 MeV C{sup 6+} ion beam in the fluence range 10{sup 9}-10{sup 13} ions/cm{sup 2}. • The glow peak induced by C ions has a linear response in the range 10{sup 9

  20. Thermoluminescence properties of Al2O3:Tb nanoparticles irradiated by gamma rays and 85 MeV C6+ ion beam

    International Nuclear Information System (INIS)

    Salah, Numan; Alharbi, Najlaa D.; Habib, Sami S.; Lochab, S.P.

    2015-01-01

    Carbon ions beam is recently recognized as an ideal cancer treatment modality, because of its excellent local tumor control. These ions have a high relative biological effectiveness resulting from high linear energy transfer (LET) and their sharp Bragg peak. However, the dose of those energetic ions needs to be measured with great precision using a proper dosimeter. Aluminum Oxide (Al 2 O 3 ) is a highly luminescent phosphor widely used for radiation dosimetry using thermoluminesence (TL) technique. In this work nanoparticles of this material activated by different elements like Eu, Tb, Dy, Cu and Ag were evaluated for their TL response to gamma rays irradiation. Tb doped sample is found to be the most sensitive sample, which could be selected for exposure to 85 MeV C 6+ ion beam in the fluence range 10 9 –10 13 ions/cm 2 . The obtained result shows that C ion beam irradiated sample has a simple glow curve structure with a prominent glow peak at around 230 °C. This glow curve has a dosimetric peak better than those induced by gamma rays. This glow peak exhibits a linear response in the range 10 9 –10 11 ions/cm 2 , corresponding to the equivalent absorbed doses 0.285–28.5 kGy. The absorbed doses, penetration depths and main energy loss were calculated using TRIM code based on the Monte Carlo simulation. The wide linear response of Al 2 O 3 :Tb nanoparticles along with the low fading makes this low cost nanomaterial a good candidate for C ion beam dosimetry. - Highlights: • Nanoparticles of Al 2 O 3 doped with Eu, Tb, Dy, Cu and Ag were synthesised. • They were evaluated for their TL response to gamma rays and C ion beam irradiation. • Tb doped sample is the most sensitive sample to gamma rays. • Al 2 O 3 :Tb was exposed to 85 MeV C 6+ ion beam in the fluence range 10 9 -10 13 ions/cm 2 . • The glow peak induced by C ions has a linear response in the range 10 9 -10 11 ions/cm 2